A description is given of an extrusion process for the preparation of a low-dust stabiliser, using a subcooled melt as granulation liquid, as well as of novel amorphous modifications of different stabilisers, including 2,2xe2x80x2-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol), and of the xcex2-crystalline modification of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole and of the preparation thereof. The novel process affords products which are easy to handle and which are flowable, and the novel modifications have advantages as regards their preparation, processing and their use as stabiliser.

The present invention relates to a process for the preparation of low-dust stabilisers by extruding a subcooled melt, to the use of the products of this process for stabilising organic polymers, to novel amorphous modifications, e.g. of 2,2xe2x80x2-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol), to a novel crystalline modification of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, to a process for its preparation and processing as well as to compositions stabilised therewith.
The development of stabiliser which are low-dust and therefore generally easier to handle has been pursued for some time; specific stabilisers have, inter alia, been mounted on inorganic substrates (e.g. U.S. Pat. No. 5,238,605).
GB-A-2267499 describes the preparation of a mixture of tetraalkylpiperidine type stabilisers of high and low molecular weight by mixing in a melted state.
U.S. Pat. No. 5,597,857 describes a process for the preparation of low-dust stabilisers by extruding a calcium stearate melt; JP-A-59-104348 and EP-A-565184 also propose extruding a melt. DE-A-19541242 proposes pastillising a mixture consisting of crystalline and melted plastic additives.
The use of a regular melt during extrusion is only possible to a limited degree owing to its low viscosity.
Amorphous modifications of individual stabilisers and their use for stabilising organic polymers have already been described, inter alia, in EP-A-278579, U.S. Pat. No. 4,683,326, EP-A-255743, U.S. Pat. No. 5,373,040, U.S. Pat. No. 5,489,636, JP-A-59-104348, U.S. Pat. No. 5,574,166. They are usually prepared by rapidly cooling (chilling) the melt to prevent crystallisation. EP-A-278579 describes the preparation of a partially crystalline stabiliser mixture consisting of amorphous tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane and a crystalline organic phosphite by subcooling the melt.
EP-A-514784 describes the extrusion of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane and the mixtures thereof with inorganic salts of fatty acid salts at temperatures in the melting range.
Surprisingly, it has now been found that the metastable state which is passed during the preparation of low molecular weight amorphous stabilisers, the subcooled melt, is excellently suitable for use as granulation liquid or binder during the extrusion. It is remarkable that the formation of crystalline modifications of the low molecular weight stabilisers is unexpectedly highly inhibited, making it possible to process the plastic extrusion compositions to granules by conventional methods.
Accordingly, this invention relates to a process for the preparation of a low-dust stabiliser, which comprises extruding a subcooled melt of a stabiliser having a molecular weight of 200 to 1500 g/mol, or the plastic composition of the mixture consisting of the subcooled melt of the stabiliser and of a crystalline stabiliser and/or other customary additives. The plastic composition therefore consists of the subcooled melt as homogeneous continuous phase and, where appropriate, of further components dispersed therein (disperse phase(s)).
The processing to marketable, low-dust, flowable and storage-stable forms with good meterability, e.g. for pelletisation, pastillation, melt granulation and compounding, is thus made substantially easier or possible at all. The moulding of the product can, for example, also be carried out before or during the cooling process by dividing the subcooled melt or the mixture, for example by dripping in the liquid state or by dividing in the plastic state with subsequent cooling. The process of this invention therefore also encompasses a process for granulating a stabiliser, which comprises extruding and dividing a subcooled melt of the stabiliser or the plastic compound consisting of the mixture of the subcooled melt of the stabiliser and of crystalline stabiliser and/or other customary additives. Solidification after extrusion gives a low-dust stabiliser, e.g. as granules.
This invention also relates to the granules obtainable by the novel process as well as to the use of a subcooled melt for extruding a stabiliser or stabiliser mixture, in particular for pelletisation, melt granulation or compounding.
The subcooled melt is single-phase and accordingly has only one single glass transition temperature; it can, however, consist of one or several chemical compounds and it preferably consists of 1 to 3 main components. Main components are to be understood as being those compounds, the proportion of which in the subcooled melt is 10% by weight or more, preferably 30% by weight or more. Also important is a subcooled melt which consists mainly, i.e. usually to 60% by weight or more, preferably to 70% by weight or more, of 1 chemical compound (weight always being based on the total weight of the homogeneous subcooled melt).
The amount of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane in the subcooled melt is preferably less than 80% by weight, more preferably from 0-60% by weight. A particularly important process of this invention is that, wherein tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane is not a main component of the subcooled melt.
The molecular weight of the chemical compounds forming the subcooled melt (main components) is usually 300-1200 g/mol, preferably 300-1000 g/mol, particularly preferably 500-1000 g/mol. These chemical compounds are normally one or several organic compounds, for example hydrocarbons containing 6 to 100 carbon atoms and, where appropriate, 1 to 30 hetero atoms, such as O, N, S, P, halogen. The melting point (m.p.) of the chemical compound, which forms a main component, preferably any component present to more than 5% by weight, is usually 130xc2x0 C. or higher, preferably 140xc2x0 C. or higher, more preferably 170xc2x0 C. or higher, and the glass transition temperature (TG) is in the range from 10-120xc2x0 C., preferably from 20-100xc2x0 C. The ratio of glass transition temperature (TG) to melting point (m.p.), each measured in Kelvin (K), is preferably in the range from 0.6 to 0.9; more preferably in the range from 0.65 to 0.85.
The compounds which form the subcooled melt are usually light stabilisers or antioxidants, for example those cited in the list given hereinbelow under the items 1, 2 and 4, provided they meet the stated criteria regarding molecular weight, melting point and glass transition temperature. They preferably belong to the class consisting of UV absorbers, sterically hindered amines (HALS), phenolic antioxidants, phosphites, phosphonites, lactones. In the novel process it is generally possible to use those compounds which, by themselves or as mixtures, are obtainable also in single-phase amorphous form by chilling the melt.
The following compounds are preferably used in the novel process:
1) 2,2xe2x80x2-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol) (CAS reg. No. 103597-45-1) of formula
2) bis(2-methyl-4-hydroxy-5-tert-butylphenyl)sulfide (CAS reg. No. 000096-69-5),
3)
(CAS reg. No. 069851-61-2),
4) N,Nxe2x80x2-bis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionyl)hexamethylenediamine (CAS reg. No. 023128-74-7),
5) 1,3,5-trimethyl-2,4,6-tris(3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxybenzyl)benzene (CAS reg. No. 001709-70-2),
6) 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione (CAS reg. No. 027676-62-6),
7)
(CAS reg. No. 032687-78-8),
8) 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)1,3,5-triazine-2,4,6-(1H,3H,5H)trione (CAS reg. No. 040601-76-1),
9) di(1,2,2,6,6-pentamethylpiperidin-4-yl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate (CAS reg. No. 063843-89-0),
10) 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-bis(1,1-dimethylbenzyl)phenyl)benzotriazole (CAS reg. No. 070321-86-7) of formula
11) 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-di-tert-butylphenyl)benzotriazole (CAS reg. No.003846-71-7);
12) isomeric mixtures (CAS reg. No. 181314-48-7) consisting of about 85% by weight of 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)-benzofuranone and about 15% by weight of 5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone;
13) pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate) (CAS reg. No. 006683-19-8);
14) 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (CAS reg. No. 3864-99-1)
15)
(CAS reg. No. 080410-33-9);
16) tris(2,4-di-tert-butylphenyl)phosphite (CAS reg. No.031570-04-4);
17)
(CAS reg. No. 26741-53-7);
18)
CAS reg. No. 37042-77-6);
19) 2-[2xe2x80x2-hydroxy-3xe2x80x2-(xcex1-xcex1-dimethylbenzyl)-5xe2x80x2-(1,1,3,3-tetramethyl-butyl)phenyl]benzotriazole of formula
(CAS reg. No. 073936-91-1).
The following Table provides the molecular weight (Mw), melting point (m.p.; DSC +4xc2x0 C./min), melt enthalpy (xcex94H), glass transition temperature (Tg; DSC +20xc2x0 C./min) and preferred processing temperature (Tp) of these compounds:
The subcooled melt is conveniently obtained by rapidly cooling a regular melt, the final temperature being below the melting point (m.p.) of the main component, preferably below the regular melting point (m.p.) of the component having the lowest melting point (usually called only melting point hereinafter). The final temperature is preferably in the range of the processing temperature stated further on. The cooling process can be carried out in a manner known per se, for example by introducing a melt to the cooled extruder, melting the stabiliser in the extruder and then transporting the melt into a corresponding cooled zone, or by preparing the subcooled melt outside of the extruder. The melt can result direct from the synthesis of a compound or from melting one or several compounds. The subcooled melt can also be obtained by rapidly melting a solid amorphous compound to a temperature from the glass transition temperature to the melting point of the crystalline modification, preferably in the range of the processing temperature. Depending on the cooling method or cooling speed, the melt can also be processed to an amorphous or partially amorphous product, for example pellets, using a melt screw or extruder.
It has furthermore been found that the subcooled single-phase melt can surprisingly also contain a smaller proportion of compounds, for example up to 40% by weight, in particular up to 30 or 20% by weight, in dissolved form, the glass transition temperature (TG) of which is below 10xc2x0 C., meaning that they cannot be obtained in amorphous form by chilling processes using customary cooling temperatures up to about 0xc2x0 C.; the precondition being that the glass transition temperature of the resulting phase is above 10xc2x0 C., in particular above 20xc2x0 C. These compounds usually also belong to the group of the light stabilisers or antioxidants as indicated above for the compounds forming the subcooled melt.
The subcooled melt and components which may be dispersed therein form the extrudable plastic composition. The subcooled melt component in the novel extrusion is preferably from 5 to 100% by weight, more preferably from 20 to 100% by weight, most preferably from 50 to 100% by weight, of the plastic composition. Other dispersed components, if present, are preferably crystalline at the processing temperature. Dispersed further components are usually conventional additives, for example the classes and products cited hereinbelow as possible co-additives. It is preferred to use, in particular, phenolic antioxidants, organic phosphites or phosphonites as well as sterically hindered amines.
Extrusion will be understood in this connection as being any process warranting a transport of the plastic composition, often via a screw, with suitable tempering. The plastic composition is usually additionally mixed and/or moulded after passage through a tempered zone, for example to granules, pellets or strands.
The plastic additives (stabilisers) are advantageously processed in a single- or twin-screw extruder. Such extruders are known in the plastics processing industry and are marketed, for example, by Buss (CH), Brabender (DE), Werner and Pfleiderer (DE) or Bxc3xchler (CH).
After or also while the still-soft extruded product is cut and after passage through a die or perforated plate, the granule particles are often cooled. Cooling can be carried out in the form of wet cooling with water (for example in water, via a water film, water ring etc.) or, preferably, with air (for example air film, air vortex etc.), or also combined. Cooling with water requires subsequent dehydration and drying (preferably in a vortex drier or fluidised-bed drier). The technical implementations of these cooling methods are known. Granulation is preferably carried out while the material is still in the plastic state, prior to the actual cooling step, in contrast to the extrusion granulation and grinding process usual in the state of the art.
The processing temperature of the plastic composition is preferably about in the middle between the regular melting point (m.p.) and the glass transition temperature (TG) of the homogeneous phase. The processing temperature is preferably in the range from TMIN to TMAX, where with (m.p.)xe2x88x92(TG)=xcex94:
TMIN=TG+0.2xcex94
TMAX=TG+0.6xcex94;
particularly preferably:
TMIN=TG+0.3xcex94
TMAX=TG+0.5xcex94.
In other of its aspects, this invention relates to granules which are obtainable by the novel process as well as to the use of a subcooled melt of a stabiliser for extrusion, in particular for pelletisation, melt granulation or compounding.
Depending on the implementation and cooling conditions, the novel process affords a crystalline, partially crystalline or completely amorphous product.
Accordingly, this invention also relates to a single-phase amorphous stabiliser comprising 2 or more compounds having have a molecular weight in the range from 300-1000 g/mol.
Novel Amorphous Modifications
This invention also relates to novel amorphous forms of stabiliser, known so far only in their crystalline modification, namely the compounds
1) 2,2xe2x80x2-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol) (CAS reg. No. 103597-45-1) of formula
2) bis(2-methyl-4-hydroxy-5-tert-butylphenyl)sulfide (CAS reg. No. 000096-69-5),
3)
(CAS reg. No. 069851-61-2),
4) N,Nxe2x80x2-bis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionyl)hexamethylenediamine (CAS reg. No. 023128-74-7),
5) 1,3,5-trimethyl-2,4,6-tris(3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxybenzyl)benzene (CAS reg. No. 001709-70-2)
6) 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione (CAS reg. No. 027676-62-6)
7)
(CAS reg. No. 032687-78-8)
8) 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)1,3,5-triazine-2,4,6-(1H,3H,5H)trione (CAS reg. No. 040601-76-1)
9) di(1,2,2,6,6-pentamethylpiperidin-4-yl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate (CAS reg. No. 063843-89-0),
10) 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-bis(1,1-dimethylbenzyl)phenyl)benzotriazole (CAS reg. No. 070321-86-7) of formula
11) 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-di-tert-butylphenyl)benzotriazole (CAS reg. No.003846-71-7);
12) isomeric mixture of 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)benzofuranone and 5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone;
14) 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, synonymous with 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl, phenol (CAS reg. No. 3864-99-1), of formula
18)
(CA-reg. No. 37042-77-6)
Compound 12, an isomeric mixture, has the CAS reg. No.181314-48-7 and consists of about 85% by weight 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)-benzofuranone and about 15% by weight 5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone.
These compounds are at the same time particularly preferred compounds for use in the extrusion process described at the outset.
The cited compounds are effective for stabilising organic material against the harmful action of light, heat and oxygen. Compound (1) and its use has been described, inter alia, in U.S. Pat. Nos. 4,812,498, 4,948,666, 4,681,905, and its preparation in U.S. Pat. Nos. 5,229,521 and 4,812,498; compound (14) is particularly effective as UV absorber and its preparation is described, inter alia, in U.S. Pat. Nos. 4,001,266, 4,041,044, 4,219,480, 4,230,867 and 4,999,433; the known xcex1-modification of compound (14) has, in pure form, a melting point of about 156xc2x0 C. and is commercially available under the trade name Tinuvin(copyright) 327.
The novel amorphous forms of compound 1-12, 14, and 18 give a line-free X-ray diffraction diagram, e.g. with Cu-kxcex1-radiation. They are also characterised by their glass transition temperature (Tg) which, for example in compound 14, is in the range from 20-30xc2x0 C., in particular from 20-25xc2x0 C.
The preparation of the amorphous form of compounds 1-12, 14 and also 18 is conveniently carried out by the novel process or, in particular, by rapidly cooling (chilling) the melt, preferably starting from a temperature of a little above the melting point or higher, typically 1-30xc2x0 C. above the melting point, to a temperature below the glass transition temperature (Tg), for example 20-50xc2x0 C. below Tg.
This can be done in known manner, for example by application to a cooled surface (e.g. a cooling conveyer), introduction into a cooled nonreactive liquid or by cooling in a stream of gas, for example with air or nitrogen. The temperature of the solid or liquid cooling medium is preferably below 100xc2x0 C., in particular below 50xc2x0 C., for example in the range from 0-50xc2x0 C., preferably in the range from 5-20xc2x0 C.; the temperature of the stream of gas used for cooling is preferably 20xc2x0 C. or lower, for example in the range from 0-20xc2x0 C., preferably from 0-10xc2x0 C.
The preparation of the amorphous form of compound 14 is conveniently carried out by rapidly cooling (chilling) a melt of the compound, preferably starting from a temperature of 159xc2x0 C. or more to a temperature of 20xc2x0 C. or lower.
This can be done in known manner, for example by application to a cooled surface, introduction into a cooled nonreactive liquid or by cooling in a stream of gas, for example with air or nitrogen. The temperature of the cooling medium is preferably below 20xc2x0 C., in particular below 10xc2x0 C., for example in the range from xe2x88x9210 to +15xc2x0 C., preferably from xe2x88x925 to +5xc2x0 C.
The amorphous solid so obtained can be comminuted by known methods, for example by grinding, to any desired particle size, the product temperature conveniently being kept below the glass transition temperature.
The novel amorphous modifications are distinguished over the crystalline modifications by a number of advantages, inter alia, in preparation, further processing and use. Rapidly cooling the melt to below the glass transition temperature, for example, results in the heat of crystallisation not being released (in the case of cmpd. (1) about 85-88 J/g), so that less energy needs to be eliminated by cooling and the cooling time of the oxidation-sensitive products can be reduced. The incorporation and distribution in the material to be stabilised is furthermore facilitated by the lack of heat of fusion. The novel modifications are dissolved more easily and homogeneously in, on the one hand, organic solvents, such as lubrication oils, lubricants, urethanes, prepolymers and others and, on the other hand, in the organic material to be stabilised, for example the organic polymer. Thus it is possible to achieve a more uniform distribution in the substrate, to prevent inhomogeneity as well as to obtain good processibility and excellent effectiveness.
In addition, the plastic metastable state of the subcooled melts makes processing in the extruder possible, where either the pure amorphous form can be used or a mixture consisting of the novel amorphous modification and of the customary crystalline form and/or other customary additives.
This invention therefore also relates to a mixture consisting of a subcooled melt or of an amorphous solid of one or several of compounds 1-12, 14, and 18, of a crystalline compound and/or of a customary stabiliser, the proportion of the novel amorphous modification preferably being from 5 to 100% by weight, in particular from 20 to 100% by weight, of the mixture and wherein, in particular, the customary stabiliser can be either solid or also amorphous.
Particularly important are in this connection the amorphous mixtures which usually have the same advantageous application properties as the amorphous single compounds. Many low molecular weight compounds, such as those cited above, are soluble in one another in the melt and are capable of forming eutectic mixtures. In mixtures, the component having the lowest melting point can serve as solvent for one or several other components. Thus it is possible to obtain multicomponent single-phase amorphous mixtures which are distinguished by having only one single glass transition temperature Tg.
Owing to the interaction of the individual compounds, the mixture physically has a novel amorphous structure, the Tg value of which can be derived from the Tg values of the individual amorphous modifications and their concentration. Accordingly, it is possible to selectively prepare single-phase microhomogeneous mixtures by mixing these compounds with one another or by admixing other low molecular weight additives, such as the compounds No. 13, 15, 16, 17 which, as is known, also have an amorphous modification. It is even possible to use some additives which are only known in crystalline form, the Tg of which is far below 15xc2x0 C. (e.g. compound bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate) in a small amount. The glass transition temperature can here be adjusted preferably to between 40 and 100xc2x0 C. by skillful combination of the compounds to warrant on the one hand an amorphous stabiliser which melts easily and at low temperature (energetically favourable, advantageous for certain applications) and, on the other hand, good storage stability.
Novel Crystalline Modification of Compound No. 14
It has furthermore been found that a novel crystal modification (xcex2-form; high-temperature modification) can be obtained by equilibrating 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compound No. 14) in a specific temperature range. This crystal modification is distinguished over the conventional xcex1-crystalline form by enhanced performance properties, such as higher bulk density and compacted bulk density, flowability, improved dispersibility in the substrate and less evolution of dust when handled and this modification also constitutes an object of this invention.
The physical properties of the novel xcex2-modifications of compound 14 have a number of differences as compared to the xcex1-modification, some of which have been found to be as follows:
The following Table provides the interplanar spacings determined by X-ray diffraction (Cu-kxcex1-radiation; measurement of the powder diagrams in transmission geometry using a Guinier camera) for the known xcex1-form as well as for the novel xcex2-crystalline form (d, given in xc3x85=10xe2x88x9210 m) and reflection intensities (visually determined):
Characteristic of the xcex2-form are, for example, the reflexes corresponding to the interplanar spacings (d) at d=9.4xc2x710xe2x88x9210 m; at d=4.69xc2x710xe2x88x9210 m; d=3.94xc2x710xe2x88x9210 m and d=3.79xc2x710xe2x88x9210 m (high or medium intensity).
The inventive modification of compound 14 can be obtained by equilibrating the compound at a temperature of above 70xc2x0 C., preferably above 95xc2x0 C., more preferably above 106xc2x0 C., and then cooling it rapidly, preferably to 15-20xc2x0 C. or lower. Suitable for equilibration are, for example, tempering as well as dissolving and/or melting processes with mixing, for example during the extrusion in the novel process. Crystallisation prior to the cooling process gives the xcex2-crystalline form, the amorphous form being obtained otherwise.
The preparation of the xcex2-crystalline form is conveniently carried out by crystallising compound 14 above 70xc2x0 C., typically above 95-106xc2x0 C., preferably above 106xc2x0 C., or by tempering the xcex1-crystalline form in the temperature range from 70xc2x0 C., preferably from 95xc2x0 C., most preferably from 106xc2x0 C., and at a melting point of the xcex1-crystalline form; i.e. typically in the range from 106xc2x0 C. to 155xc2x0 C., preferably from 110C. to 150xc2x0 C., with subsequent rapid cooling of the xcex2-crystalline form obtained typically to 50xc2x0 C. or lower, preferably to 15-30xc2x0 C. or room temperature (20-25xc2x0 C.) or lower.
Crystallisation can be carried out by the customary methods of the art, for example by crystallisation from a solution or subcooled melt of compound which is kept below the melting point, or by cooling a melt.
The cooling process from a temperature of above 70xc2x0 C., such as above 95-106xc2x0 C. or above 156xc2x0 C., to 50xc2x0 C. or room temperature can proceed continuously or discontinuously, the cooling rate being slowed or stopped in the range from 95 to 156xc2x0 C., preferably from 106-150xc2x0 C. The cooling process can usefully also be combined with the moulding of the product, e.g. granulation or pastillation. Typical examples of concrete processes are fluid bed granulation or prilling.
For tempering, the compound is heated either direct or with addition of a suitable solvent, e.g. xylene, toluene or a mixture of xylene and butanol with a sufficiently high boiling point, conveniently for about 20 minutes to 24 hours to a temperature in the cited range. Cooling is then carried out as indicated above.
Suitable solvents are, for example, those having a boiling point which is markedly higher than 95xc2x0 C., in particular higher than 106xc2x0 C., at normal pressure, preferably alcohols or hydrocarbons, such as toluene, xylene or mesitylene or their mixtures. The use of solvents having lower boiling points is also possible, in which case the pressure is usefully increased such that the solvent remains liquid in the cited temperature range. Such solvents can subsequently be removed more easily than the high-boiling solvents mentioned at the outset.
When using a solvent, compound 14 can also be dissolved completely or partially, and the crystallisation of the dissolved components can then be achieved, inter alia, by gentle cooling to the lower range of the cited temperature range, for example to 70-100xc2x0 C., 95-110xc2x0 C. or 106-120xc2x0 C., and/or by removing the solvent by distillation.
The xcex2-crystalline product can, if required, be brought into any other desired form of presentation and particle size by known methods, such as grinding, compressing, extruding or granulating.
The use of mixtures of the novel modifications with one another and with the customary xcex1-crystalline modification has also advantages of the cited kind over the use of the pure xcex1-crystalline modification. The novel mixture consisting of different modifications of compound 14 preferably contains at least 40% by weight, preferably at least 60% by weight, more preferably at least 80% by weight, of xcex2-crystalline and/or amorphous form and not more than 50% by weight, preferably not more than 20% by weight, more preferably not more than 10% by weight, of foreign components (each based on the total weight of the mixture).
Another advantage of the novel xcex2-modification of compound 14 consists in the easier and more homogeneous solubility in, on the one hand, organic solvents, such as lubrication oils, lubricants, urethanes, prepolymers and others and, on the other hand, in the organic material to be stabilised, for example the organic polymer, such that a more uniform distribution is achieved therein, inhomogeneity is prevented and excellent effectiveness is warranted.
The novel modifications of compound 14 are particularly suitable for stabilising organic materials, for example in particular the organic polymers cited hereinbelow, against damage by light, oxygen or heat. The novel modifications are very particularly suitable as light stabilisers (UV absorbers).
Colour-stabilisation of Compound No. 13
Amorphous pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate) (CAS reg. No. 006683-19-8; compound No. 13), which is usually obtained as a colourless powder during synthesis, quickly darkens during storage, the product taking on a greenish to yellow hue (greening). Depending on the storage conditions, in particular on exposure to light and oxygen, this unwanted effect occurs usually after about 4-12 weeks.
The use of mixtures comprising this compound in the novel extrusion process surprisingly shows that in the case of certain additives the colour stability of the amorphous compound 13 is markedly improved and the greening effect is prevented or at least slowed down very much. It is important in this connection that a microhomogeneous amorphous mixture is obtained.
In another of its aspects, this invention therefore also relates to a process for stabilising the colour of amorphous pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate), which comprises admixing a stabiliser of the class consisting of the organic phosphites, phosphonites and/or benzofuran-2-ones to a melt of pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate) and rapidly cooling the mixture so obtained.
The use of a stabiliser of the class consisting of the organic phosphites, phosphonites and/or benzofuran-2-ones for stabilising the colour of amorphous pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate) is another object of this invention.
The compound No. 13 colour-stabilised in this manner forms a microhomogeneous phase together with the stabiliser. The stabiliser component (organic phosphite, phosphonite and/or benzofuran-2-one) in this phase is preferably at least 1% by weight, typically 1-95% by weight, in particular 5-90% by weight, more preferably 5 to 55% by weight.
The cooling process which gives the partially amorphous or, preferably, single-phase amorphous colour-stabilised compound No. 13 can be carried out in the manner described above for the preparation of the novel amorphous modifications.
In this connection, phosphites or organic phosphites will be understood as meaning the compounds of formula P(OR)3, wherein the radicals R are hydrocarbon radicals which may contain hetero atoms, and where a maximum of two of the three radicals R may additionally be hydrogen atoms. Hetero atoms are all atoms with the exception of carbon and hydrogen, in particular the N, O, F, Si, P, S, Cl, Br, Sn and I atoms.
Phosphonites are esters of the phosphonous acid of formula P(OR)2R, wherein R has the meanings given above or may be halogen.
Phosphites or phosphinites preferably used in the inventive process are those, which correspond to one of formulae (1) to (7),
wherein the indices are integers, and
nxe2x80x2 is 2, 3 or 4; p is 1 or 2; q is 2 or 3; r is 4 to 12; y is 1, 2 or 3; and z is 1 to 6;
Axe2x80x2, if nxe2x80x2 or q is 2, is alkylene of 2 to 18 carbon atoms; alkylene of 2 to 12 carbon atoms which is interrupted by xe2x80x94Sxe2x80x94, xe2x80x94Oxe2x80x94 or xe2x80x94NRxe2x80x24xe2x80x94; a radical of one of formula
or phenylene;
Axe2x80x2, if nxe2x80x2 or q is 3, is a radical of formula xe2x80x94CrH2r-1xe2x80x94;
Axe2x80x2, if nxe2x80x2 is 4, is the radical of formula C(CH2)4;
Axe2x80x3 has the meaning of Axe2x80x2, if nxe2x80x2 is 2;
Bxe2x80x2 is a radical of formula xe2x80x94CH2xe2x80x94; xe2x80x94CHRxe2x80x24xe2x80x94; xe2x80x94CRxe2x80x21Rxe2x80x24xe2x80x94; xe2x80x94Sxe2x80x94 or a direct bond; or C5-C7cycloalkylidene; or cyclohexylidene which is substituted by 1 to 4 C1-C4alkyl radicals in position 3, 4 and/or 5;
Dxe2x80x2, if p is 1, is methyl and, if p is 2, is xe2x80x94CH2OCH2xe2x80x94;
Exe2x80x2, if y is 1, is alkyl containing 1 to 18 carbon atoms, a radical of formula xe2x80x94ORxe2x80x2, or halogen;
Exe2x80x2, if y is 2, is a radical of formula xe2x80x94Oxe2x80x94Axe2x80x3xe2x80x94Oxe2x80x94;
Exe2x80x2, if y is 3, is a radical of formula Rxe2x80x24xe2x80x94C(CH2O)3xe2x80x94;
Qxe2x80x2 is the radical of an at least z-valent alcohol or phenol, which radical is bound via the alcoholic or phenolic O-atom(s) to the P-atom(s);
Rxe2x80x21, Rxe2x80x22 and Rxe2x80x23 are each independently of one another alkyl containing 1 to 30 carbon atoms; alkyl containing 1 to 18 carbon atoms, which is substituted by halogen, xe2x80x94COOR4xe2x80x2, xe2x80x94CN or xe2x80x94CONR4xe2x80x2R4xe2x80x2; alkyl containing 2 to 18 carbon atoms, which is interrupted by xe2x80x94Sxe2x80x94, xe2x80x94Oxe2x80x94 or xe2x80x94NRxe2x80x24xe2x80x94; phenyl-C1-C4alkyl; cycloalkyl containing 5 to 12 carbon atoms; phenyl or naphthyl; phenyl or naphthyl, each of which is substituted by halogen, 1 to 3 alkyl radicals or alkoxy radicals containing a total of 1 to 18 carbon atoms or by phenyl-C1-C4alkyl; or a radical of formula
wherein m is an integer from the range of 3 to 6;
Rxe2x80x24, or the radicals R4xe2x80x2, are each independently of one another hydrogen; alkyl containing 1 to 18 carbon atoms; cycloalkyl containing 5 to 12 carbon atoms; or phenylalkyl containing 1 to 4 carbon atoms in the alkyl moiety;
Rxe2x80x25 and Rxe2x80x26 are each independently of the other hydrogen; alkyl containing 1 to 8 carbon atoms, or cycloalkyl containing 5 or 6 carbon atoms;
Rxe2x80x27 and Rxe2x80x28, where q=2, are each independently of the other C1-C4alkyl or are together a 2,3-dehydropentamethylene radical; and
Rxe2x80x27 and Rxe2x80x28, where q=3, are methyl;
the substituents Rxe2x80x214 are each independently of one another hydrogen; alkyl containing 1 to 9 carbon atoms or cyclohexyl;
the substituents Rxe2x80x215 are each independently of one another hydrogen or methyl; and
Rxe2x80x216 is hydrogen or C1-C4alkyl, and in the case where several radicals Rxe2x80x216 are present, the radicals Rxe2x80x216 are identical or different;
Xxe2x80x2 and Yxe2x80x2 are each a direct bond or xe2x80x94Oxe2x80x94; and
Zxe2x80x2 is a direct bond; xe2x80x94CH2xe2x80x94; xe2x80x94C(Rxe2x80x216)2xe2x80x94 or xe2x80x94Sxe2x80x94.
A particularly preferred process is that, wherein the phosphite or phosphonite is one of formula (1), (2), (5) or (6), wherein
nxe2x80x2 is the number 2, and y is the number 1 or 2;
Axe2x80x2 is alkylene containing 2 to 18 carbon atoms; p-phenylene or p-biphenylene;
Exe2x80x2, where y=1, is C1-C18alkyl, xe2x80x94OR1 or fluoro; and where y=2, is p-biphenylene;
Rxe2x80x21, Rxe2x80x22 and Rxe2x80x23 are each independently of one another alkyl containing 1 to 18 carbon atoms; phenyl-C1-C4alkyl; cyclohexyl; phenyl; phenyl which is substituted by 1 to 3 alkyl radicals containing a total of 1 to 18 carbon atoms;
the substituents Rxe2x80x214 are each independently of one another hydrogen or alkyl containing 1 to 9 carbon atoms;
Rxe2x80x215 is hydrogen or methyl;
Xxe2x80x2 is a direct bond;
Yxe2x80x2 is xe2x80x94Oxe2x80x94; and
Zxe2x80x2 is a direct bond or xe2x80x94CH(Rxe2x80x216)xe2x80x94.
Of particular technical interest are those phosphites or phosphonites which are listed hereinafter in the list of possible costabilisers under item 4.
In the novel process those benzofuran-2-ones are preferably used, which correspond to formula (8)
wherein, if n is 1,
R1 is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, dibenzofuryl, chromenyl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, xcex2-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, hydroxy, halogen, amino, C1-C4alkylamino, phenylamino or di(C1-C4alkyl)amino, or R1 is a radical of formula 9
and
if n is 2,
R1 is unsubstituted or C1-C4alkyl- or hydroxy-substituted phenylene or naphthylene; or xe2x80x94R12xe2x80x94Xxe2x80x94R13xe2x80x94,
R2, R3, R4 and R5 are each independently of one another hydrogen, chloro, hydroxy, C1-C25-alkyl, C7-C9phenylalkyl, unsubstituted or C1-C4alkyl-substituted phenyl; unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl; C1-C18alkoxy, C1-C18alkylthio, C1-C4alkylamino, di(C1-C4-alkyl)amino, C1-C25alkanoyloxy, C1-C25alkanoylamino, C3-C25alkenoyloxy; C3-C25alkanoyloxy which is interrupted by oxygen, sulfur or
C6-C9cycloalkylcarbonyloxy, benzoyloxy or C1-C12alkyl-substituted benzoyloxy; or R2 and R3, or R3 and R4, or R4 and R5, together with the linking carbon atoms, are a benzene ring, R4 is additionally xe2x80x94(CH2)pxe2x80x94COR15 or xe2x80x94(CH2)qOH or, if R3, R5 and R6 are hydrogen, R4 is additionally a radical of formula 10
wherein R1 is as defined above for n=1,
R6 is hydrogen or a radical of formula 11
wherein R4 is not a radical of formula 10 and R1 is as defined above for n=1,
R7, R8, R9, R10 and R11 are each independently of one another hydrogen, halogen, hydroxy, C1-C25alkyl; C2-C25alkyl which is interrupted by oxygen, sulfur or
C1-C25alkoxy; C2-C25alkoxy which is interrupted by oxygen, sulfur or
C1-C25alkylthio, C3-C25-alkenyl, C3-C25alkenyloxy, C3-C25alkynyl, C3-C25alkynyloxy, C7-C9phenylalkyl, C7-C9phenylalkoxy, unsubstituted or C1-C4alkyl-substituted phenyl; unsubstituted or C1-C4alkyl-substituted phenoxy; unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkyl; unsubstituted or C1-C4alkyl-substituted C5-C8cycloalkoxy; C1-C4alkylamino, di(C1-C4alkyl)amino, C1-C25alkanoyl; C3-C25alkanoyl which is interrupted by oxygen, sulfur or
C1-C25alkanoyloxy; C3-C25alkanoyloxy which is interrupted by oxygen, sulfur or
C1-C25alkanoylamino, C3-C25alkenoyl; C3-C25alkenoyl which is interrupted by oxygen, sulfur or
C3-C25-alkenoyloxy; C3-C25alkenoyloxy which is interrupted by oxygen, sulfur or
C6-C9-cycloalkylcarbonyl, C6-C9cycloalkylcarbonyloxy, benzoyl or C1-C12alkyl-substituted benzoyl; benzoyloxy or C1-C12alkyl-substituted benzoyloxy;
or
or also, in formula 9, R7 and R8, or R8 and R11, together with the linking carbon atoms, are a benzene ring,
R12 and R13 are each independently of the other unsubstituted or C1-C4alkyl-substituted phenylene or naphthylene,
R14 is hydrogen or C1-C8alkyl,
R5 is hydroxy,       [                  xe2x80x94O        -                          1        r                          M                  r          +                      ]    ,
C1-C18alkoxy or
R16 and R17 are each independently of the other hydrogen, CF3, C1-C12alkyl or phenyl, or R16 and R17, together with the linking carbon atom, are a C5-C8cycloalkylidene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl;
R18 and R19 are each independently of the other hydrogen, C1-C4alkyl or phenyl,
R20 is hydrogen or C1-C4alkyl,
R21 is hydrogen, unsubstituted or C1-C4alkyl-substituted phenyl; C1-C25alkyl; C2-C25alkyl which is interrupted by oxygen, sulfur or
C7-C9phenylalkyl which is unsubstituted or substituted at the phenyl radical by 1 to 3 C1-C4alkyl; C7-C25phenylalkyl which is interrupted by oxygen, sulfur or
which is unsubstituted or substituted at the phenyl radical by 1 to 3 C1-C4alkyl, or R20 and R21, together with the linking carbon atoms, are a C5-C12cycloalkylene ring which is unsubstituted or substituted by 1 to 3 C1-C4alkyl;
R22 is hydrogen or C1-C4alkyl,
R23 is hydrogen, C1-C25alkanoyl, C3-C25alkenoyl; C3-C25alkanoyl which is interrupted by oxygen, sulfur or
C2-C25alkanoyl which is substituted by a di(C1-C6alkyl)phosphonate group; C6-C9cycloalkylcarbonyl, thenoyl, furoyl, benzoyl or C1-C12alkyl-substituted benzoyl;
R24 and R25 are each independently of the other hydrogen or C1-C18alkyl,
R26 is hydrogen or C1-C8alkyl,
R27 is a direct bond, C1-C18alkylene; C2-C18alkylene which is interrupted by oxygen, sulfur or
C2-C18alkenylene, C2-C20alkylidene, C7-C20phenylalkylidene, C5-C8cycloalkylene, C7-C8bicycloalkylene, unsubstituted or C1-C4alkyl-substituted phenylene,
R28 is hydroxy,       [                  xe2x80x94O        -                          1        r                          M                  r          +                      ]    ,
C1-C18alkoxy or
R29 is oxygen, xe2x80x94NHxe2x80x94 or
R30 is C1-C18alkyl or phenyl,
R31 is hydrogen or C1-C18alkyl,
M is an r-valent metal cation,
X is a direct bond, oxygen, sulfur or xe2x80x94NR31xe2x80x94,
n is 1 or 2,
p is 0, 1 or 2,
q is 1, 2, 3, 4, 5 or 6,
r is 1, 2 or 3, and
s is 0, 1 or 2.
Benzofuran-2-ones of particular technical interest are those which are listed hereinafter in the list of possible costabilisers under item 14.
Furthermore, this invention relates to a composition, which comprises
a) pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate), and
b) at least one compound of the benzofuran-2-one type.
The novel compositions contain pentaerythritol-tetrakis(3-[3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl]propionate) (component a) preferably in amorphous form. Particularly preferred compositions are those, which comprise components a and b side by side in the same amorphous phase. The inventive stabiliser compositions usually contain less than 10% by weight of high molecular weight or polymeric components, typically those having a molecular weight of 1500 g/mol or higher; there are mostly no such high molecular weight components present.
Use as Stabiliser for Organic Material
The products of the process of this invention, the novel amorphous compounds, the colour-stabilised compound 13 according to this invention, and also the novel xcex2-crystalline modification of compound 14 are particularly suitable for stabilising organic materials against damage by light, oxygen or heat.
The materials to be stabilised may be, for example, oils, fats, paint systems, cosmetics, photographic materials or biocides. Particularly interesting is the use in polymeric materials, as is the case in plastics, rubbers, coating materials, photographic material or sizes. When used in cosmetic preparations, the material to be protected is often not the preparation itself, but the skin or hair to which the preparation is applied.
Illustrative examples of polymers and other substrates which can be stabilised in this manner are:
1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), (VLDPE) and (ULDPE).
Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:
a) radical polymerisation (normally under high pressure and at elevated temperature).
b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or VIII of the Periodic Table. These metals usually have one or more than one ligand, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either xcfx80- or "sgr"-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(III) chloride, alumina or silicon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups Ia, IIa and/or IIIa of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).
2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).
3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/ ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EM), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides.
4. Hydrocarbon resins (for example C5-C9) including hydrogenated modifications thereof (e.g. tackifiers) and mixtures of polyalkylenes and starch.
5. Polystyrene, poly(p-methylstyrene), poly(xcex1-methylstyrene).
6. Copolymers of styrene or xcex1-methylstyrene with dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkyl methacrylate, styrene/maleic anhydride, styrene/acrylonitrile/methyl acrylate; mixtures of high impact strength of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; and block copolymers of styrene such as styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/ styrene.
7. Graft copolymers of styrene or xcex1-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (or methacrylonitrile) on polybutadiene; styrene, acrylonitrile and methyl methacrylate on polybutadiene; styrene and maleic anhydride on polybutadiene; styrene, acrylonitrile and maleic anhydride or maleimide on polybutadiene; styrene and maleimide on polybutadiene; styrene and alkyl acrylates or methacrylates on polybutadiene; styrene and acrylonitrile on ethylene/propylene/diene terpolymers; styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadiene copolymers, as well as mixtures thereof with the copolymers listed under 6), for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers.
8. Halogen-containing polymers such as polychloroprene, chlorinated rubbers, chlorinated and brominated copolymer of isobutylene-isoprene (halobutyl rubber), chlorinated or sulfochlorinated polyethylene, copolymers of ethylene and chlorinated ethylene, epichlorohydrin homo- and copolymers, especially polymers of halogen-containing vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluride, as well as copolymers thereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers.
9. Polymers derived from xcex1,xcex2-unsaturated acids and derivatives thereof such as polyacrylates and polymethacrylates; polymethyl methacrylates, polyacrylamides and polyacrylonitriles, impact-modified with butyl acrylate.
10. Copolymers of the monomers mentioned under 9) with each other or with other unsaturated monomers, for example acrylonitrile/ butadiene copolymers, acrylonitrile/alkyl acrylate copolymers, acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.
11. Polymers derived from unsaturated alcohols and amines or the acyl derivatives or acetals thereof, for example polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well as their copolymers with olefins mentioned in 1) above.
12. Homopolymers and copolymers of cyclic ethers such as polyalkylene glycols, polyethylene oxide, polypropylene oxide or copolymers thereof with bisglycidyl ethers.
13. Polyacetals such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.
14. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with styrene polymers or polyamides.
15. Polyurethanes derived from hydroxyl-terminated polyethers, polyesters or polybutadienes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as precursors thereof.
16. Polyamides and copolyamides derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and with or without an elastomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing (RIM polyamide systems).
17. Polyureas, polyimides, polyamide-imides, polyetherimids, polyesterimids, polyhydantoins and polybenzimidazoles.
18. Polyesters derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, for example polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates, as well as block copolyether esters derived from hydroxyl-terminated polyethers; and also polyesters modified with polycarbonates or MBS.
19. Polycarbonates and polyester carbonates.
20. Polysulfones, polyether sulfones and polyether ketones.
21. Crosslinked polymers derived from aldehydes on the one hand and phenols, ureas and melamines on the other hand, such as phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.
22. Drying and non-drying alkyd resins.
23. Unsaturated polyester resins derived from copolyesters of saturated and unsaturated dicarboxylic acids with polyhydric alcohols and vinyl compounds as crosslinking agents, and also halogen-containing modifications thereof of low flammability.
24. Crosslinkable acrylic resins derived from substituted acrylates, for example epoxy acrylates, urethane acrylates or polyester acrylates.
25. Alkyd resins, polyester resins and acrylate resins crosslinked with melamine resins, urea resins, isocyanates, isocyanurates, polyisocyanates or epoxy resins.
26. Crosslinked epoxy resins derived from aliphatic, cycloaliphatic, heterocyclic or aromatic glycidyl compounds, e.g. products of diglycidyl ethers of bisphenol A and bisphenol F, which are crosslinked with customary hardeners such as anhydrides or amines, with or without accelerators.
27. Natural polymers such as cellulose, rubber, gelatin and chemically modified homologous derivatives thereof, for example cellulose acetates, cellulose propionates and cellulose butyrates, or the cellulose ethers such as methyl cellulose; as well as rosins and their derivatives.
28. Blends of the aforementioned polymers (polyblends), for example PP/EPDM, polyamide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPO, PBT/PC/ABS or PBT/PET/PC.
This invention therefore also relates to a composition, which comprises
A) an organic material susceptible to oxidative, thermal or/and actinic degradation or build-up, and
B) the amorphous form of one of the compounds No. 1-12, 14, 18, the colour-stabilised amorphous compound 13 and/or the xcex2-crystalline form of the compound 14 as stabiliser, as well as to the use of the amorphous form of one of the compounds No. 1-12, 14, 18, of the colour-stabilised amorphous compound 13 and/or of the xcex2-crystalline form of compound 14 for stabilising organic material against oxidative, thermal or actinic degradation or build-up.
Component B is preferably the amorphous form of one of the compounds No. 1-12, 14, 18 and also the xcex2-crystalline form of compound 14.
The invention also relates to a process for stabilising organic material against thermal, oxidative or/and actinic degradation or build-up, which comprises applying the amorphous form of one of the compounds No. 1-12, 14, 18, the colour-stabilised amorphous compound 13 and/or the xcex2-crystalline form of compound 14 to this material and/or preferably adding them thereto, as well as to the corresponding use. The amorphous form of one of the compounds No. 1-12, 14, 18, the colour-stabilised amorphous compound 13 and/or the xcex2-crystalline form of compound 14 can be used here by itself or as component of a mixture of the amorphous form of one or several compounds No. 1-12, 14, 18, of the colour-stabilised amorphous compound 13 and/or of the xcex2-crystalline form of compound 14 with the conventional crystalline form and/or other conventional additives.
The amount of the stabiliser (amorphous and, if required, crystalline) to be used in total depends on the organic material to be stabilised and on the intended use of the stabilised material. The novel composition generally comprises, per 100 parts by weight of component A, 0.01 to 15, preferably 0.05 to 10 and, more preferably, 0.1 to 5, parts by weight of the novel stabiliser (novel amorphous modification of one of the compounds No. 1-12, 14, 18, colour-stabilised amorphous compound 13 and/or xcex2-crystalline form of compound 14 or mixture comprising a novel amorphous or xcex2-crystalline modification).
Particularly interesting is the use of the novel stabiliser in synthetic organic polymers as well as corresponding compositions, in particular thermoplastic polymers which are processed at elevated temperatures, for example by extruding, blow moulding, calendering, injection moulding, casting, compressing, sintering, spinning, foaming, soldering, laminating, heat-moulding, and the like.
The organic materials to be protected are preferably natural, semi-synthetic or synthetic organic materials.
The novel stabiliser can be used particularly advantageously in compositions which comprise as component A a synthetic organic polymer, preferably a thermoplastic polymer or a binder for coatings, such as paint systems. Suitable thermoplastic polymers are, for example, polyolefins, preferably polyethylene (PE) and polypropylene (PP), as well as those polymers which contain hetero atoms in the main chain.
In a preferred aspect, this invention also relates to a composition wherein the novel modification is incorporated in a thermoplastic polymer, in a paint binder, in particular one based on an acrylic, alkyd, polyurethane, polyester or polyamide resin or corresponding modified resins, or in a photographic material. The material to be protected (component A) can in this case be a thermoplastic polymer, a paint binder, in particular based on an acrylic, alkyd, polyurethane, polyester or polyamide resin or corresponding modified resins, a photographic material, or a colourant present in this material.
Particularly interesting is also the use of the novel modifications as stabiliser for coatings, for example for paint systems.
The incorporation in the materials to be stabilised can, for example, be carried out by admixing or applying the novel stabiliser and, if required, other additives, by the customary methods of the art. In the case of polymers, in particular of synthetic polymers, the incorporation can be carried out before or after moulding, or by applying the dissolved or dispersed compound to the polymer, if required with subsequent evaporation of the solvent. Elastomers can also be stabilised as latices. Another possibility of incorporating the novel stabiliser in polymers consists in their addition before, during or immediately after the polymerisation of the corresponding monomers or before crosslinking. The amorphous or xcex2-crystalline compound can in this case be added as such or also in encapsulated form (e.g. in waxes, oils or polymers). If the stabiliser is added before or during the polymerisation, it can also serve as chain length regulator (chain terminator) for the polymers.
The novel stabiliser can also be added to the plastics to be stabilised in the form of a master-batch which comprises the stabiliser e.g. in a concentration of 2.5 to 25% by weight.
The incorporation of the novel stabiliser may conveniently be carried out by the following methods:
as emulsion or dispersion (e.g. to latices or emulsion polymers),
as dry mixture before mixing additive components or polymer mixtures,
by direct addition to the processing apparatus (e.g. extruder, internal mixer, etc.)
as solution or melt.
The novel stabiliser is preferably added to the polymer before or after processing, preferably as dry mixture during the mixing of additive components or polymer mixtures, or by direct addition to the processsing apparatus.
Polymer compositions of this invention can be used in different form or can be processed to different products, e.g. foils, fibres, filaments, moulding compositions, profiles, or binders for paint systems, sizes or putties.
In addition to the novel stabiliser, the novel compositions can comprise as additional component (C) one or several conventional additives, such as antioxidants, further light stabilisers, metal deactivators, phosphites or phosphonites. Illustrative examples thereof are:
1. Antioxidants
1.1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-di-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(xcex1-methylcyclohexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1xe2x80x2-methylundec-1xe2x80x2-yl)phenol, 2,4-dimethyl-6-(1xe2x80x2-methylheptadec-1xe2x80x2-yl)phenol, 2,4-dimethyl-6-(1xe2x80x2-methyltridec-1xe2x80x2-yl)phenol and mixtures thereof.
1.2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl-4-nonylphenol.
1.3. Hydroquinones and alkylated hydroquinones, for example 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.
1.4. Tocopherols, for example xcex1-tocopherol, xcex2-tocopherol, xcex3-tocopherol, xcex5-tocopherol and mixtures thereof (Vitamin E).
1.5. Hydroxylated thiodiphenyl ethers, for example 2,2xe2x80x2-thiobis(6-tert-butyl-4-methylphenol), 2,2xe2x80x2-thiobis(4-octylphenol), 4,4xe2x80x2-thiobis(6-tert-butyl-3-methylphenol), 4,4xe2x80x2-thiobis(6-tert-butyl-2-methylphenol), 4,4xe2x80x2-thiobis-(3,6-di-sec-amylphenol), 4,4xe2x80x2-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.
1.6. Alkylidenebisphenols, for example 2,2xe2x80x2-methylenebis(6-tert-butyl-4-methylphenol), 2,2xe2x80x2-methylenebis(6-tert-butyl-4-ethylphenol), 2,2xe2x80x2-methylenebis[4-methyl-6-(xcex1-methylcyclohexyl)phenol], 2,2xe2x80x2-methylenebis(4-methyl-6-cyclohexylphenol), 2,2xe2x80x2-methylenebis(6-nonyl-4-methylphenol), 2,2xe2x80x2-methylenebis(4,6-di-tert-butylphenol), 2,2xe2x80x2-ethylidenebis(4,6-di-tert-butylphenol), 2,2xe2x80x2-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2xe2x80x2-methylenebis[6-(xcex1-methylbenzyl)-4-nonylphenol], 2,2xe2x80x2-methylenebis[6-(xcex1,xcex1-dimethylbenzyl)-4-nonylphenol], 4,4xe2x80x2-methylenebis(2,6-di-tert-butylphenol), 4,4xe2x80x2-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis(3xe2x80x2-tert-butyl-4xe2x80x2-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene, bis[2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.
1.7. O-, N- and S-benzyl compounds, for example 3,5,3xe2x80x2,5xe2x80x2-tetra-tert-butyl-4,4xe2x80x2-dihydroxydibenzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.
1.8. Hydroxybenzylated malonates, for example dioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate, didodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.
1.9. Aromatic hydroxybenzyl compounds, for example 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.
1.10. Triazine compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.
1.11. Benzylphosphonates, for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.
1.12. Acylaminophenols, for example 4-hydroxylauranilide, 4-hydroxystearanilide, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.
1.13. Esters of xcex2-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,Nxe2x80x2-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
1.14. Esters of xcex2-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,Nxe2x80x2-bis-(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
1.15. Esters of xcex2-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,Nxe2x80x2-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,Nxe2x80x2-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.
11.17. Amides of xcex2-(3,5-di-tert-butyl-4-hydroxylphenyl)propionic acid e.g. N,Nxe2x80x2-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide, N,Nxe2x80x2-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide, N,Nxe2x80x2-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide, N,Nxe2x80x2-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide (Naugard(copyright)XL-1 supplied by Uniroyal).
1.18. Ascorbic acid (vitamin C)
1.19. Aminic antioxidants, for example N,Nxe2x80x2-di-isopropyl-p-phenylenediamine, N,Nxe2x80x2-di-sec-butyl-p-phenylenediamine, N,Nxe2x80x2-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,Nxe2x80x2-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,Nxe2x80x2-bis(1-methylheptyl)-p-phenylenediamine, N,Nxe2x80x2-dicyclohexyl-p-phenylenediamine, N,Nxe2x80x2-diphenyl-p-phenylenediamine, N,Nxe2x80x2-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-Nxe2x80x2-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-Nxe2x80x2-phenyl-p-phenylenediamine, N-(1-methylheptyl)-Nxe2x80x2-phenyl-p-phenylenediamine, N-cyclohexyl-Nxe2x80x2-phenyl-p-phenlenediamine, 4-(p-toluenesulfamoyl)diphenylamine, N,Nxe2x80x2-dimethyl-N,Nxe2x80x2-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy diphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, for example p,pxe2x80x2-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylaminomethylphenol, 2,4xe2x80x2-diaminodiphenylmethane, 4,4xe2x80x2-diaminodiphenylmethane, N,N,Nxe2x80x2,Nxe2x80x2-tetramethyl-4,4xe2x80x2-diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane, (o-tolyl)biguanide, bis[4-(1xe2x80x2,3xe2x80x2-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyl-diphenylamines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyldiphenylamines, a mixture of mono- und dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- und dialkylated tert-butyl/tert-octylphenothiazines, a mixture of mono- und dialkylated tert-octyl-phenothiazines, N-allylphenothiazin, N,N,Nxe2x80x2,Nxe2x80x2-tetraphenyl-1,4-diaminobut-2-ene, N,N-bis-(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine, bis(2,2,6,6-tetramethylpiperid-4-yl)-sebacate, 2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.
2. UV absorbers and light stabilisers
2.1. 2-(2xe2x80x2-Hydroxyphenyl)benzotriazoles, for example 2-(2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl)benzotriazole, 2-(3xe2x80x2,5xe2x80x2-di-tert-butyl-2xe2x80x2-hydroxyphenyl)benzotriazole, 2-(5xe2x80x2-tert-butyl-2xe2x80x2-hydroxyphenyl)benzotriazole, 2-(2xe2x80x2-hydroxy-5xe2x80x2-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3xe2x80x2,5xe2x80x2-di-tert-butyl-2xe2x80x2-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3xe2x80x2-tert-butyl- 2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl)-5-chloro-benzotriazole, 2-(3xe2x80x2-sec-butyl-5xe2x80x2-tert-butyl-2xe2x80x2-hydroxyphenyl)benzotriazole, 2-(2xe2x80x2-hydroxy-4xe2x80x2-octyloxyphenyl)benzotriazole, 2-(3xe2x80x2,5xe2x80x2-di-tert-amyl-2xe2x80x2-hydroxyphenyl)benzotrazole, 2-(3xe2x80x2,5xe2x80x2-bis-(xcex1,xcex1-dimethylbenzyl)-2xe2x80x2-hydroxyphenyl)benzotriazole, 2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3xe2x80x2-tert-butyl-5xe2x80x2-[2-(2-ethylhexyloxy)-carbonylethyl]-2xe2x80x2-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2-(3xe2x80x2-tert-butyl-5xe2x80x2-[2-(2-ethylhexyloxy)carbonylethyl]-2xe2x80x2-hydroxyphenyl)benzotriazole, 2-(3xe2x80x2-dodecyl-2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl)benzotriazole, 2-(3xe2x80x2-tert-butyl-2xe2x80x2-hydroxy-5xe2x80x2-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2xe2x80x2-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2-[3xe2x80x2-tert-butyl-5xe2x80x2-(2-methoxycarbonylethyl)-2xe2x80x2-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; [Rxe2x80x94CH2CH2xe2x80x94COOxe2x80x94CH2CH2xe2x80x94]2 where R=3xe2x80x2-tert-butyl-4xe2x80x2-hydroxy-5xe2x80x2-2H-benzotriazol-2-ylphenyl, 2-[2xe2x80x2-hydroxy-3xe2x80x2-(xcex1,xcex1-dimethylbenzyl)-5xe2x80x2-(1,1,3,3-tetramethylbutyl)phenyl]-benzotriazole; 2-[2xe2x80x2-hydroxy-3xe2x80x2-(1,1,3,3-tetramethylbutyl)-5xe2x80x2-(xcex1,xcex1-dimethylbenzyl)phenyl]-benzotriazole.
2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2xe2x80x2,4xe2x80x2-trihydroxy and 2xe2x80x2-hydroxy-4,4xe2x80x2-dimethoxy derivatives.
2.3. Esters of substituted and unsubstituted benzoic acids, as for example 4-tertbutyl-phenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl) resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.
2.4. Acrylates, for example ethyl xcex1-cyano-xcex2,xcex2-diphenylacrylate, isooctyl xcex1-cyano-xcex2,xcex2-diphenylacrylate, methyl xcex1-carbomethoxycinnamate, methyl xcex1-cyano-xcex2-methyl-p-methoxy-cinnamate, butyl xcex1-cyano-xcex2-methyl-p-methoxy-cinnamate, methyl xcex1-carbomethoxy-p-methoxycinnamate and N-(xcex2-carbomethoxy-xcex2-cyanovinyl)-2-methylindoline.
2.5. Nickel compounds, for example nickel complexes of 2,2xe2x80x2-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenyl undecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additional ligands.
2.6. Sterically hindered amines, for example bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensates of N,Nxe2x80x2-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate, 1,1xe2x80x2-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cyclic condensates of N,Nxe2x80x2-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis-(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1 -(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product of N,Nxe2x80x2-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid, N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro [4,5]decane und epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene, N,Nxe2x80x2-bis-formyl-N,Nxe2x80x2-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine, diester of 4-methoxymethylene-malonic acid with 1,2,2,6,6-pentamethyl-4-hydroxypiperidine, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, reaction product of maleic acid anhydride-xcex1-olefin-copolymer with 2,2,6,6-tetramethyl-4-aminopiperidine or 1,2,2,6,6-pentamethyl-4-aminopiperidine.
2.7. Oxamides, for example 4,4xe2x80x2-dioctyloxyoxanilide, 2,2xe2x80x2-diethoxyoxanilide, 2,2xe2x80x2-dioctyloxy-5,5xe2x80x2-di-tert-butoxanilide, 2,2xe2x80x2-didodecyloxy-5,5xe2x80x2-di-tert-butoxanilide, 2-ethoxy-2xe2x80x2-ethyloxanlide, N,Nxe2x80x2-bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2xe2x80x2-ethoxanilide and its mixture with 2-ethoxy-2xe2x80x2-ethyl-5,4xe2x80x2-di-tert-butoxanilide, mixtures of o- and p-methoxy-disubstituted oxanilides and mixtures of o- and p-ethoxy-disubstituted oxanilides.
2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, 2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxy-propoxy)phenyl]-1,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.
3. Metal deactivators, for example N,Nxe2x80x2-diphenyloxamide, N-salicylal-Nxe2x80x2-salicyloyl hydrazine, N,Nxe2x80x2-bis(salicyloyl)hydrazine, N,Nxe2x80x2-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide, oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide, N,Nxe2x80x2-diacetyladipoyl dihydrazide, N,Nxe2x80x2-bis(salicyloyl)oxalyl dihydrazide, N,Nxe2x80x2-bis(salicyloyl)thiopropionyl dihydrazide.
4. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite, diisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4xe2x80x2-biphenylene diphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin, bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite, 2,2xe2x80x2,2xe2x80x3-nitrilo[triethyltris(3,3xe2x80x2,5,5xe2x80x2-tetra-tert-butyl-1,1xe2x80x2-biphenyl-2,2xe2x80x2-diyl)phosphite], 2-ethylhexyl(3,3xe2x80x2,5,5xe2x80x2-tetra-tert-butyl-1,1xe2x80x2-biphenyl-2,2xe2x80x2-diyl)phosphite.
Especially preferred are the following phosphites:
Tris(2,4di-tert-butylphenyl) phosphite (Irgafos(copyright) 168, Ciba-Geigy), tris(nonylphenyl) phosphite,
5. Hydroxylamines, for example N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N-dhexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.
6. Nitrones, for example N-benzyl-alpha-phenyl-nitrone, N-ethyl-alpha-methyl-nitrone, N-octyl-alpha-heptyl-nitrone, N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridcyl-nitrone, N-hexadecyl-alpha-pentadecyl-nitrone, N-octadecyl-alpha-heptadecyl-nitrone, N-hexadecyl-alpha-heptadecyl-nitrone, N-ocatadecyl-alpha-pentadecyl-nitrone, N-heptadecyl-alpha-heptadecyl-nitrone, N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived from N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.
7. Thiosynergists, for example dilauryl thiodipropionate or distearyl thiodipropionate.
8. Peroxide scavengers, for example esters of xcex2-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis(xcex2-dodecylmercapto)propionate.
9. Polyamide stabilisers, for example copper salts in combination with iodides and/or phosphorus compounds and salts of divalent manganese.
10. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali metal salts and alkaline earth metal salts of higher fatty acids, for example, calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or zink pyrocatecholate.
11. Nucleating agents, for example inorganic substances such as talcum, metal oxides such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, preferably, alkaline earth metals; organic compounds such as mono- or polycarboxylic acids and the salts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds such as ionic copolymers (ionomers).
12. Fillers and reinforcing agents, for example calcium carbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite, wood flour and flours or fibers of other natural products, synthetic fibers.
13. Other additives, for example plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents.
14. Benzofuranones and indolinones, for example those disclosed in U.S. Pat. Nos. 4,325,863; 4,338,244; 5,175,312; 5,216,052; 5,252,643; DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839 or EP-A-0591102 or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one, 3,3xe2x80x2-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one], 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butylbenzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.
The type and amount of the further stabilisers added is determined by the type of substrate to be stabilised and by its envisaged use; often, 0.0005-10, for example 0.001-5, preferably 0.01-2.5%, by weight, based on the material to be stabilised, are added.
It is particularly advantageous to use the novel modifications of compounds No. 1, 10, 11 and/or 14 in combination with sterically hindered amines, for example 2,2,6,6-tetralkylpiperidine derivatives. This invention therefore relates to a synergistic stabiliser mixture, which comprises (a) the xcex2-crystalline modification of compound 14 and/or the amorphous modification of compound No. 1, 10, 11, and/or 14, and (b) at least one sterically hindered amine, the salt thereof with any acid or the complex thereof with a metal, as well as to a composition, which comprises
A) an organic material susceptible to oxidative, thermal or/and actinic degradation or build-up,
B) the xcex2-crystalline modification of compound 14 and/or the amorphous modification of compound No. 1, 10, 11, and/or 14, and also
C) a conventional additive of the sterically hindered amine type.
Preferred sterically hindered amines are, for example, those which are given in the above list under item 2.6.
It is also particularly advantageous to use the novel modifications in combination with costabilisers of the 2-(2-hydroxyphenyl)-1,3,5-triazine type, as exemplified in the above list under item 2.8.


An image forming apparatus includes a sensor that is configured to detect a property of a developer material, a transport unit that is operatively in contact with the developer material and that is configured to move the developer material toward a recording medium, and a controller that receives the property of the developer material from the sensor unit and sets a voltage of the transport unit, wherein the voltage is determined based on the property of the developer material received from the sensor.

This disclosure is generally directed to electrostatographic imaging devices. More specifically, this disclosure is directed to reducing or eliminating the image quality defect known as reload.
In the known process of electrostatographic printing, a charge retentive surface, typically known as a photoreceptor, is electrostatically charged and then exposed to a pattern of activating electromagnetic radiation, such as light. The radiation selectively dissipates the charge on the illuminated areas of the charge retentive surface while leaving behind an electrostatic image on the non-illuminated surfaces. The resulting pattern of charged and discharged areas on the photoreceptor form an electrostatic charge pattern, known as a latent image, conforming to the original image.
The latent image is then developed by contacting it with an electrostatically attractable toner. Toner is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the image being produced. The toner image may then be transferred to a substrate or recording medium, and the image is fixed to form a permanent record of the image. Subsequent to development, excess toner left on the charge retentive surface is cleaned from the surface. The process is useful for copying from an original or printing electronically generated or stored originals.
In the operation of electrostatographic printing there arises a defect known as reload. Reload describes a situation where a roller within a development station fails to properly and completely be reloaded with the appropriate amount of toner after one cycle through the development process in preparation for the next cycle. Reload becomes more and more drastic when a machine engaging in electrostatographic image production is used to produce large quantities of images at high speeds.


There is provided a speech encoder for performing an algorithm that comprises obtaining (205) a plurality of open-loop pitch candidates from a current frame of a speech signal, the plurality of open-loop pitch candidates including a first open-loop pitch candidate and a second open-loop pitch candidate; obtaining (205) a voicing information from one or more previous frames; and selecting (280) one of the plurality of open-loop pitch candidates as a final pitch of the current frame using the voicing information from the one or more previous frames. In one aspect, the voicing information from the one or more previous frames includes a previous pitch of the one or more previous frames. In a further aspect, selecting the final pitch of the current frame includes selecting (210) an initial open-loop pitch from that has the maximum long-term correlation value.

1. Field of the Invention
The present invention relates generally to speech coding. More particularly, the present invention relates to open-loop pitch analysis.
2. Related Art
Speech compression may be used to reduce the number of bits that represent the speech signal thereby reducing the bandwidth needed for transmission. However, speech compression may result in degradation of the quality of decompressed speech. In general, a higher bit rate will result in higher quality, while a lower bit rate will result in lower quality. However, modern speech compression techniques, such as coding techniques, can produce decompressed speech of relatively high quality at relatively low bit rates. In general, modern coding techniques attempt to represent the perceptually important features of the speech signal, without preserving the actual speech waveform. Speech compression systems, commonly called codecs, include an encoder and a decoder and may be used to reduce the bit rate of digital speech signals. Numerous algorithms have been developed for speech codecs that reduce the number of bits required to digitally encode the original speech while attempting to maintain high quality reconstructed speech.
In 1996, the Telecommunication Sector of the International Telecommunication Union (ITU-T) adopted a toll quality speech coding algorithm known as the G.729 Recommendation, entitled "Coding of Speech Signals at 8 kbit/s using Conjugate-Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP)," which is hereby incorporated by reference in its entirety into the present application.
FIG. 1 illustrates the speech signal flow in CS-ACELP (Conjugate Structure Algebraic-Code-Excited-Linear-Prediction) encoder 100 of the G.729 Recommendation, as explained therein. The reference numerals adjacent to each block in FIG. 1 indicate section numbers within the G.729 Recommendation that describe the operation and functionality of each block. As shown, the speech signal or input samples 105 enter the high pass & down scale block (described in Section 3.1 of the G.729 Recommendation), where pre-processing 110 is applied to input samples 105 on a frame-by-frame basis. Next, LP analysis 115 and open-loop pitch search 120 are applied to the pre-processed speech signal on a frame-by-frame basis. Following the open-loop pitch search 120, closed-loop pitch search 125 and algebraic search 130 are applied to the speech signal on a subframe-by-subframe basis, as shown in FIG. 1, which results in generating code index output 135.
As illustrated in FIG. 1, open-loop pitch search 120 includes find open-loop pitch delay 124, which is described at Section 3.4 of the G.729 Recommendation. As explained therein, to reduce the complexity of the search for the best adaptive-codebook delay, the search range is limited around a candidate delay Top, obtained from an open-loop pitch analysis. This open-loop pitch analysis is done once per frame (10 ms). The open-loop pitch estimation uses the weighted speech signal sw(n) from compute weighted speech 122, and is implemented as follows.
In the first step, three maxima of correlation:
            R                    (        k        )              =                  ∑                  n          =          0                79                                    sw                                (            n            )                                            sw                                (                          n              -              k                        )                                    where    ,                                    sw                          (          n          )                    =                        s                                (            n            )                          +                              ∑                          i              =              1                                      10                                                                                a              i                                                  y              1              i                                                  s                                            (                                  n                  -                  i                                )                                                    -                              ∑                          i              =              1                        10                                                        a              i                                                  y              2              i                                                  sw                                            (                                  n                  -                  i                                )                                                                    n      =      0        ,    …                      ,    39  are found in the following three ranges:                i=1:80, . . . , 143        i=2:40, . . . , 79        i=3:20, . . . , 39
The retained maxima R(ti), i=1, . . . , 3, are normalized through:
                    R        ′                          (                  t          i                )              =                  R                          (                      t            i                    )                                                  ∑            n                                                        sw              2                                                  (                              n                -                                  t                  i                                            )                                                      i      =      1        ,    …                      ,    3
Next, the winner among the three normalized correlations is selected by favoring the delays with the values in the lower range. This is done by weighting the normalized correlations corresponding to the longer delays. The best open-loop delay Top is determined as follows:
  Top = t1  R′(Top) = R′(t1)  if R′(t2) ≧ 0.85R′(Top)    R′(Top) = R′(t2)    Top = t2  end  if R′(t3) ≧ 0.85R′(Top)R′(Top) = R′(t3)    Top = t3  end
The above-described procedure of dividing the delay range into three sections and favoring the smaller values is used to avoid choosing pitch multiples. The smoothed open-loop pitch track can help stabilize the speech perceptual quality. More specifically, smoothed pitch track can make pitch prediction (pitch estimation for lost frames) easier when applying frame erasure concealment algorithm at the decoder side. The above-described conventional algorithm of the G.729 Recommendation, however, does not provide an optimum result and can be further improved. For example, disadvantageously, the conventional algorithm of the G.729 Recommendation only uses the current frame information to smooth the open-loop pitch track in order to avoid pitch multiples.
Accordingly, there is a need in the art to improve conventional open-loop pitch analysis to obtain a smoother open-loop pitch track for stabilizing the speech perceptual quality.


A method for forming an image sensor device. An alignment mark is formed on or in a substrate with distance from the alignment mark to the substrate edge less than about 3 mm. An array of active photosensing pixels is formed on the substrate. At least one dielectric layer is formed covering the substrate and the array. A color filter photoresist is formed on the least one dielectric layer. Subsequent to removal of the color filter photoresist from the alignment mark, the color filter photoresist is exposed with alignment to the alignment mark.

The invention relates to an electronic device, and more particularly, to an image sensor device.
CMOS image sensor devices are used in a wide variety of, applications, such as digital still camera (DSC) applications. These devices utilize an array of active pixels or image sensor cells, comprising photodiode elements, to collect photo energy for conversion of images to streams of digital data.
FIG. 1 is a cross section of a typical image sensor device. In FIG. 1, a typical image sensor device 100 is illustrated in cross section, comprising a semiconductor substrate 101 having an array of photodiodes 120 therein. Each photodiode 120 comprises, for example, an n-type region 124 in a p-type region 122. Each photodiode 120 is separated from other photodiodes by an array of isolation structures 110, such as shallow trench isolation (STI). Thus, an array of pixels is obtained. The pixels convert incoming light 160 from a light/image source to electrical signals via the photodiodes 124. The substrate 101 is covered by a series of dielectric layers 130, such as an interlevel dielectric (ILD) layer and intermetal dielectric (IMD) layers. A color filter layer 140 overlying the substrate 101 comprises red regions 140a, green regions 140b and blue regions 140c.
FIG. 2 illustrates curves of wavelength versus transmittance of three major colors. In FIG. 2, the blue curve presents extremely low transmittance at a wavelength of about 580 Ř650 Å. Exposure apparatuses, such as steppers, typically use light with wavelength of 633 Å for alignment. Consequently, extremely low transmittance of the blue photoresist of the color filter is likely to cause alignment failure.

Taiwan Semiconductor Manufacturing Co., Ltd.