The present invention relates to a powder coating composition containing as binder one or more than one poly(meth)acrylic resin having free carboxyl groups and, as hardener for these poly(meth)acrylic resins, one or more than one epoxy resin having a molecular weight of up to 1500, wherein the epoxy resins comprise at least 70% by weight of glycidyl esters which are selected from the group consisting of aliphatic and cycloaliphatic polyglycidyl polycarboxylates. More particularly, the present invention relates to a coating composition, which is free of carboxyl-functional polyesters, comprising a binder consisting of one or more than one poly(meth)acrylic resin having free carboxyl groups and, as hardener for the poly(meth)acrylic resin, one or more than one epoxy resin having a molecular weight of up to 1500, wherein the epoxy resin is a cycloaliphatic polyglycidyl polycarboxylate or mixtures thereof.

The present invention relates to powder coating compositions based on solid poly(meth)acrylic resins having free carboxyl groups, i.e. on resins which are obtainable by polymerisation of monomers which contain acrylic monomers and/or methacrylic monomers, as well as to the use thereof as automotive lacquers.
Powder coating compositions based on poly(meth)acrylic resins are used whenever powder coating compositions of such high fastness to weathering and hardness are desired as cannot be achieved with other binder systems customarily used for powder coatings, such as polyesters. Poly(meth)acrylic resins containing specific solid carboxyl groups are, for example, sold commercially as binders for powder coatings which are intended especially for cures with triglycidyl isocyanurate and which give powder coatings having the cited properties (Johnson Wax Speciality Chemicals Product Application Bulletin, Powder Coatings). However, these powder coatings can only be used at temperatures above 160xc2x0 C. because they have only very bad flow at temperatures lower than that, resulting in a pronounced orange peel effect. In spite of good fastness to weathering they are therefore e.g. not suitable for the preparation of automotive lacquers as in this case the coating composition is required to harden at a temperature of at maximum 140-150xc2x0 C. in order not to adversely affect the coats of base lacquer during the hardening of the finishing coating composition coated thereon.
This invention provides a solution for the problem described above by providing special powder coatings based on poly(meth)acrylic resins which harden quickly and completely already at a temperature of 140-150xc2x0 C. and which have good flow properties even at these relatively low temperatures as well as good fastness to weathering. This is achieved by using epoxy resins having a molecular weight of below 1500 as hardeners for powder coatings based on poly(meth)acrylic resins having free carboxyl groups, the epoxy resins containing at least 70% by weight of aliphatic and/or cycloaliphatic polyglycidyl polycarboxylates.
Accordingly, the invention relates to a powder coating composition comprising as binder one or more than one poly(meth)acrylic resin having free carboxyl groups and, as hardeners for these poly(meth)acrylic resins, one or more than one epoxy resin having a molecular weight of up to 1500, in which powder coating composition the epoxy resins contain at least 70% by weight of glycidyl esters which are selected from the group consisting of aliphatic and cycloaliphatic polyglycidyl polycarboxylates. More particularly, the instant invention relates to an improved coating composition, which is free of carboxyl-functional polyesters, comprising a binder consisting of one or more than one poly(meth)acrylic resin having free carboxyl groups and, as hardener for the poly(meth)acrylic resin, one or more than one epoxy resin having a molecular weight of up to 1500, wherein the epoxy resin is a diglycidyl ester of a cycloaliphatic polyglycidyl polycarboxylate or mixtures thereof, the cycloaliphatic polyglycidyl polycarboxylate being selected from the group consisting of diglycidyl hexahydrophthalate, diglycidyl hexahydroisophthalate, diglycidyl hexahydroterephthalate, diglycidyl methylhexahydrophthalate, diglycidyl 2,5-dimethylhexahydrophthalate, diglycidyl N endomethylenehexahydrophthalate, diglycidyl 1,8-decalindicarboxylates, diglycidyl 2,3-decalindicarboxylates, diglycidyl 2,6-decalindicarboxylates, triglycidyl cyclohexanetricarboxylates, tetraglycidyl hexahydromellophanate and tetraglycidyl hexahydropyrromellitate.
In addition to their excellent flow properties, the powder coating compositions according to this invention also have good storability at room temperature or at moderately elevated temperatures, such as in the temperature range from 10 to 40xc2x0 C., and accordingly they also have a good reactivity/stability ratio.
Another advantage achieved in accordance with the present invention is that the powder coating compositions cure, preferably at temperatures in the range of about 100xc2x0 C. to about 150xc2x0 C., to a smooth form. The smoothness of coating surfaces can for example be objectively measured using the xe2x80x9cWave Scanxe2x80x9d profilometer of Byk-Gardner, which is a commercially available portable flow measuring instrument for characterizing xe2x80x9corange peelxe2x80x9d by optically scanning the brightness pattern reflected from a surface when it is irradiated with light emitted from a laser diode. The Byk-Gardner catalogue describing the profilometer is incorporated herein by reference,. The profilometer that is disclosed in U.S. Pat. No. 5,596,412, incorporated herein by reference, provides different measurement parameters, i.e., the parameter xe2x80x9cLong-Wavexe2x80x9d and xe2x80x9cSubnotexe2x80x9d being in particular indicative of the surface roughness and flow properties of the coating systems. A parameter xe2x80x9cLong-Wavexe2x80x9d of less than 50 and a parameter xe2x80x9cSubnotexe2x80x9d of less than 120 measured for a coating derived from a coating composition is, for the purpose of the instant invention, considered to be a sufficiently smooth surface and accordingly of good flow properties shown by said composition. The powder coating compositions according to the instant invention provide such smooth coatings having a parameter xe2x80x9cLong-Wavexe2x80x9d of less than 50, preferably less than 45, and a parameter xe2x80x9cSubnotexe2x80x9d of less than 120, preferably less than 100, even when cured at a temperature of below 160xc2x0 C., in particular at a temperature of about 100xc2x0 to about 150xc2x0 C.
Poly(meth)acrylic resins having free carboxyl groups can be obtained by copolymerisation of acrylic monomers and/or methacrylic monomers, such as C1-C12alkyl(meth)acrylates, typically methyl(meth)acrylates, ethyl(meth)acrylates, propyl(meth)acrylates, butyl(meth)acrylates, pentyl(meth)acrylates, hexyl(meth)acrylates, octyl(meth)acrylates, 2-ethylhexyl(meth)acrylates, decyl(meth)acrylates and dodecyl(meth)acrylates, C1-C4alkyl(meth)acrylates being preferred, or (meth)acrylamide with acrylic acid and/or methacrylic acid and, optionally, other additional ethylenically unsaturated comonomers, typically vinylaromatics, e.g. styrene, xcex1-methylstyrene, vinyltoluene or also xcex2-halogenated styrenes. This copolymerisation can be carried out according to known methods, for example by dissolving the monomers in suitable organic solvents and thermally reacting them in the presence of a suitable initiator which is soluble in the solvent, such as dicumyl peroxide, as well as in the presence of a suitable chain transfer reactant such as thioglycolic acid (solution polymerisabon), or by suspending and polymerising the monomer mixture together with a solution of the initiator in an organic solvent in water, or also by emulsifying the monomer mixture using surfactants, e.g. sodium lauryl sulfate in water and reacting it in the presence of a water-soluble polymerisation initiator, such as K2S2O8 (emulsion polymerisation). The ready poly(meth)acrylic resin is then isolated in solid form from the solvent or water. The reaction can also be carried out without using solvents or water, for example in accordance with JP-A-Sho 53-140395. Suitable poly(meth)acrylic resins are solid in the temperature range from room temperature (15 to 25xc2x0 C.). They usually have a molecular weight from 1000 to 50000 (medium weight Mw), preferably from 5000 to 20000. The Tg value (glass transition temperature) of the poly(meth)acrylic resins, determined by DSC (heating rate: 10xc2x0 C./minute), is preferably from 40 to 75xc2x0 C. The acid number of the resins, indicated in mg equivalents of KOH per g of poly(meth)acrylic resin, is preferably from 30 to 160, more preferably from 35 to 80.
The aliphatic polyglycidyl polycarboxylates are preferably the aliphatic polyglycidyl polycarboxylates containing 2 to 50, particularly preferably 2 to 20, carbon atoms which may, in addition to the carboxyl groups, also contain other functional groups. Typical examples of suitable aliphatic polycarboxylic acids are oxalic acids, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, subaric acid, azelaic acid or sebacic acid. Hardeners which are also suitable for the purposes of this invention are aliphatic polyglycidyl esters of formula (I) given below, wherein X1, X2, X3, X4, X5 and X6 are each independently of one another a hydrogen atom, a C1-C4alkyl group or a group of formula (II) given below, and A in formula (II) is an alkylene group containing 2 to 4 carbon atoms, preferably an ethylene group, and Y is a hydrogen atom or a methyl group:
Polyglycidyl esters of formula (I) are disclosed, inter alia, in EP-A-0 506 617. Specific examples are glycidyl acetone-1,1,3,3-tetrapropionate and glycidyl pentanone-(3)-2,2,4,4-tetrapropionate.
Preferred aliphatic polyglycidyl polycarboxylates are diglycidyl oxalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, diglycidyl azelate.
Within this description, cycloaliphatic polyglycidyl polycarboxylates are generally understood to mean polyglycidyl polycarboxylates based on a carbon backbone containing one or more than one cycloaliphatic ring and which is free from Cxe2x80x94C multiple bonds or of aromatic groups. The individual cycloaliphatic rings can contain one or more than one substituent, typically C1-C6alkyl, chloro, brorno or hydroxyl substituents and preferably contain 5 to 10 carbon atoms. If the polycarboxylic acid contains two or more cycloaliphatic rings, then these may be fused or linked via suitable atom groups, in particular via straight-chain or branched aliphatic groups of valency 2-6 having e.g. 1 to 30 carbon atoms which may also contain one or more than one hetero atom, typically a sulfur atom, nitrogen atom or, preferably, oxygen atom, as well as substituents, such as chloro, bromo or hydroxyl substituents. Typical examples of such linking groups are those of formula xe2x80x94CH2xe2x80x94, xe2x80x94C(CH3)2xe2x80x94,  greater than CHxe2x80x94,  greater than C(CH3)xe2x80x94,  greater than C less than  or
wherein Q is an organic radical of valency 2-6 containing preferably 2 to 15 carbon atoms which is free from Cxe2x80x94C double bonds. Specific examples of cycloaliphatic polyglycidyl polycarboxylates which are suitable according to this invention are diglycidyl hexahydro-phthalate, diglycidyl hexahydroisophthalate, diglycidyl hexahydroterephthalate, diglycidyl methylhexahydrophthalate, diglycidyl 2,5-dimethylhexahydrophthalate, diglycidyl endomethylenehexahydrophthalate, diglycidyl 1,8-, 2,3- and 2,6-decalindicarboxylates, triglycidyl cyclohexanetricarboxylates, such as triglycidyl hexahydrohemimellitate or, preferably, triglycidyl hexahydrotrimesate as well as triglycidyl hexahydrotrimellitate, tetraglycidyl hexahydromellophanate (cyclohexane-1,2,3,4-tetracarboxylic acid) or tetraglycidyl hexahydro-pyrromellitate (cyclohexane-1,2,4,5-tetracarboxylic acid). Polyglycidyl cydohexanepolycarboxylates, such as triglycidyl 1,2,4 or 1,3,5-cyclohexanetricarboxylates, can, for example, also be obtained in conventional manner from the corresponding cyclohexanepolycarboxylic acids by reaction with epichlorohydrin. Where not commercially available, the cyclohexanepolycarboxylic acids can, for example, be prepared by hydration of the corresponding benzenepolycarboxylic acids in accordance with U.S. Pat. No. 3,444,237.
The cycioaliphatic polyglycidyl esters disclosed in DE-A-23 19 815 and EP-A-0 506 617 are also well suited for the powder coatings of this invention. These have the formula (III) given below, wherein n is an integer from 2 to 9, preferably from 2 to 3, and X1, X2, X3 and X4 are each independently of one another a hydrogen atom, a C1-C4alkyl group or a group of the above-mentioned formula (II):
Illustrative examples of this type of compounds are cyclopentanone-2,2,5,5-tetra(propionic acid glycidyl ester), cydohexanone-2,2,6,6-tetra(propionic acid glycidyl ester) or cyclopentanone-2,2-di(propionic acid glycidyl ester).
Other cycioaliphatic polyglycidyl esters suitable for this invention are the diglycidyl esters of the formula given below, which are also disclosed in EP-A-0 506 607, wherein X7 is an aliphatic or cycloaliphatic polyglycidyl ester of valency m containing 2 to 30 carbon atoms, the carbon chain of which may be interrupted by one or more than one hetero atom, typically a nitrogen atom, sulfur atom or, preferably, oxygen atom and which is unsubstituted or substituted and can contain in particular hydroxyl, chloro or bromo substituents, and wherein m is an integer from 2 to 6, and X8 and X9 are each independently of the other a hydrogen, chloro or bromo atom, a C1-C4alkyl group, or one of X8 or X9 is a group of the formula (V) given below, the other having one of the meanings stated above:
X7 is preferably a di- to quadrivalent radical which is derived from an aliphatic polyalcohol containing 2 to 10 carbon atoms, which may be oligomerised, typically from glycol, glycerol, trimethylolpropane or bis(trimethylolpropane), or from polyether polyols by removal of 2 to 4 hydroxyl groups, or is a di- to quadrivalent, preferably divalent, group having the following molecular structure
wherein X10 and X11 are each independently of the other a hydrogen atom, a C1-C4alkyl group or a cyclohexyl group. X10 and X11 are particularly preferably either a hydrogen atom or a methyl group. Particularly preferred compounds of this structure have the formulae (Gxe2x80x94CH2)3Cxe2x80x94C2H5, (Gxe2x80x94CH2)2C(C2H5)xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94(C2H5)C(CH2xe2x80x94G)2, (Gxe2x80x94CH2)2CH(OH) as well as Gxe2x80x94(C6H4)xe2x80x94C(CH3)2xe2x80x94(C6H4)xe2x80x94G, wherein G corresponds in each case to a group of formula (VI) and X8 is either a hydrogen atom or a group of the above formula (V):
Those powder coatings are preferred which contain the diglycidyl hexahydroterephthalate, triglycidyl 1,2,4cyclohexanetricarboxylate (triglycidyl hexahydrotrimellitate), triglycidyl 1,3,5-cyclohexanetricarboxylate (triglycidyl hexahydrotrimesate) or polyglycidyl compounds of the above formula (III) or (IV).
The powder coating of this invention can of course also comprise mixtures of several aliphatic and/or cycioaliphatic polyglycidyl polycarboxylates. However, the novel powder coating compositions can additionally also contain other solid and/or liquid epoxy resin compounds, if their amount does not exceed 30% by weight of the total amount of epoxy resins in said powder coating composition. This applies in particular also to those epoxy resin compounds which are disclosed in EP-A-0 506 617 and in EP-A-0 536 085, both descriptions of which are regarded as a component of this description, and which are mentioned there as hardeners for powder coatings based on acid polyesters and containing aromatic groups and, in particular, as hardeners for the polyglycidyl esters described therein which contain aromatic groups in the molecule, for example for aromatic polyglycidyl polycarboxylates, such as diglycidyl phthalate, diglycidyl isophthalate or diglycidyl terephthalate, or for triglycidyl trimesate or triglycidyl trimellitate.
However, a particularly advantageous embodiment of the powder coatings of this invention are those compositions wherein the epoxy resins are exclusively glycidyl esters which are selected from the group consisting of aliphatic and cycloaliphatic polyglycidyl polycarboxylates. Epoxy resins which are liquid at room temperature (10 to 25xc2x0 C.) are preferably used in the form of solid mixed phases (solid solutions) that are formed from the liquid epoxy resins which are solid at room temperature, such as described in EP-A-0 536 085.
The powder coating compositions of this invention preferably contain the epoxy resins in such an amount that the ratio of the carboxyl groups of the poly(meth)acrylic resins to the epoxy resin groups is from 0.5:1 to 2:1.
The powder coatings of this invention can additionally also contain further modifiers conventionally used in the coating industry, typically light stabilisers, curing accelerators, dyes, pigments, e.g. titanium dioxide pigment, deaerators, e.g. benzoin, and/or flow control agents. Suitable flow control agents are typically polyvinyl acetals, such as polyvinyl butyral, polyethylene glycol, polyvinyl pyrrolidone, glycerol, acrylic copolymers such as those available under the trademarks Modaflow(copyright) or Acrylron(copyright). As EP-A-0 462 053 discloses, the powder coatings of this invention may also contain solid colloidal condensation polymers consisting of urea or melamine and formaldehyde if the above-mentioned formation of solid solutions should not be utilised for the solidification of liquid epoxy resins.
Powder coatings of this invention can be prepared by simple mixing of the components, conveniently in a ball mill. Another possibility, which is more preferred, comprises fusing, mixing and homogenising the components together, preferably in an extruder such as a Buss Ko-kneader, cooling the product and comminuting it. The powder coating compositions preferably have a particle size in the range from 0.015 to 500 xcexcm, more preferably from 10 to 75 xcexcm. In some cases it may also be expedient to first prepare a masterbatch from part of the binder, the epoxy resins and, optionally, further components, and then mixing and homogenising it in a second step with the remaining binder and the remaining components to give the final powder coating composition.
After application to the object to be coated, the powder coatings are hardened at a temperature of no less than about 100xc2x0 C., preferably in the range from 120 to 140xc2x0 C. Normally about 5 to 60 minutes are required for hardening. Materials suitable for coating are all those which are stable at the temperatures necessary for the cure, in particular ceramic materials and metals. The substrate can already have one or more than one coat of base lacquer which is compatible with the powder coating.
A preferred field of application for compositions of this invention are automotive lacquers which are coated as topmost layer on one or more than one coat of base lacquer which is applied to the automobile first. Accordingly, the invention also relates to the use of the above-described powder coating compositions as automotive lacquer.


A light duty, liquid comprising of at least two different surfactants, lauryol ethylenediaminetriacetate, a zinc inorganic salt and water.

The present invention relates to novel antibacterial light duty liquid cleaning compositions with high foaming and good grease cutting properties.
The prior art is replete with light duty liquid detergent compositions containing nonionic surfactants in combination with anionic and/or betaine surfactants wherein the nonionic detergent is not the major active surfactant. In U.S. Pat. No. 3,658,985 an anionic based shampoo contains a minor amount of a fatty acid alkanolamide. U.S. Pat. No. 3,769,398 discloses a betaine-based shampoo containing minor amounts of nonionic surfactants. This patent states that the low foaming properties of nonionic detergents renders its use in shampoo compositions non-preferred. U.S. Pat. No. 4,329,335 also discloses a shampoo containing a betaine surfactant as the major ingredient and minor amounts of a nonionic surfactant and of a fatty acid mono- or di-ethanolamide. U.S. Pat. No. 4,259,204 discloses a shampoo comprising 0.8 to 20% by weight of an anionic phosphoric acid ester and one additional surfactant which may be either anionic, amphoteric, or nonionic. U.S. Pat. No. 4,329,334 discloses an anionic-amphoteric based shampoo containing a major amount of anionic surfactant and lesser amounts of a betaine and nonionic surfactants.
U.S. Pat. No. 3,935,129 discloses a liquid cleaning composition containing an alkali metal silicate, urea, glycerin, triethanolamine, an anionic detergent and a nonionic detergent. The silicate content determines the amount of anionic and/or nonionic detergent in the liquid cleaning composition. However, the foaming properties of these detergent compositions are not discussed therein.
U.S. Pat. No. 4,129,515 discloses a heavy duty liquid detergent for laundering fabrics comprising a mixture of substantially equal amounts of anionic and nonionic surfactants, alkanolamines and magnesium salts, and, optionally, zwitterionic surfactants as suds modifiers.
U.S. Pat. No. 4,224,195 discloses an aqueous detergent composition for laundering socks or stockings comprising a specific group of nonionic detergents, namely, an ethylene oxide of a secondary alcohol, a specific group of anionic detergents, namely, a sulfuric ester salt of an ethylene oxide adduct of a secondary alcohol, and an amphoteric surfactant which may be a betaine, wherein either the anionic or nonionic surfactant may be the major ingredient.
The prior art also discloses detergent compositions containing all nonionic surfactants as shown in U.S. Pat. Nos. 4,154,706 and 4,329,336 wherein the shampoo compositions contain a plurality of particular nonionic surfactants in order to affect desirable foaming and detersive properties despite the fact that nonionic surfactants are usually deficient in such properties.
U.S. Pat. No. 4,013,787 discloses a piperazine based polymer in conditioning and shampoo compositions which may contain all nonionic surfactant or all anionic surfactant.
U.S. Pat. No. 4,450,091 discloses high viscosity shampoo compositions containing a blend of an amphoteric betaine surfactant, a polyoxybutylenepolyoxyethylene nonionic detergent, an anionic surfactant, a fatty acid alkanolamide and a polyoxyalkylene glycol fatty ester. But, none of the exemplified compositions contain an active ingredient mixture wherein the nonionic detergent is present in major proportion which is probably due to the low foaming properties of the polyoxybutylene polyoxyethylene nonionic detergent.
U.S. Pat. No. 4,595,526 describes a composition comprising a nonionic surfactant, a betaine surfactant, an anionic surfactant and a C12-C14 fatty acid monoethanolamide foam stabilizer.
It has now been found that a high foaming antibacterial light duty liquid cleaning composition can be formulated with at least two surfactants, lauryol ethylene diaminetriacetate, a magnesium inorganic salt, a zinc inorganic salt, an alkali metal inorganic salt, a proton donating agent, and water.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein the novel, high foaming, light duty liquid detergent of this invention comprises at least two surfactants, lauryol ethylene diamine triacetate, a magnesium inorganic salt, a zinc inorganic salt, an alkali metal inorganic salt, a proton donating agent, and water, wherein the composition does not contain an alpha olefin sulfonate surfactant, an alkali metal salt of ethylene diamine tetraacetic acid or hydroxy ethylene diamine tetra acetic acid, a glycol ether solvent, a mono- or di-saccharides a polyoxyalkylene glycol fatty acid, a builder, a polymeric thickener, a clay, abrasive, silicas, tricloscan, alkaline earth metal carbonates, alkyl glycine surfactant or cyclic imidinium surfactant.
The present invention relates to an antibacterial light duty liquid cleaning composition which comprises approximately by weight:
(a) 5% to 55%, more preferably 10% to 45% of at least two surfactants selected from the group consisting of paraffin sulfonate, linear alkyl benzene sulfonates, alkyl sulfate, ethoxylated alkyl ether sulfate, alkyl polyglucoside, amine oxide, ethoxylated nonionics, ethoxylated/propoxylated nonionics, C12-C14 alkyl monoalkanol amides and zwitterionic surfactants and mixtures thereof;
(b) 0.5% to 10% more preferably 0.75% to 8% of lauryol ethylene diamine triacetate;
(c) 0.25% to 10% of a solubilizing agent;
(d) 0.25% to 5% of a magnesium inorganic salt;
(e) 0.25% to 5% of an alkali metal inorganic salt;
(f) 0.01% to 2% of a proton donating agent;
(g) 0.25% to 2% of a zinc inorganic salt; and
(h) the balance being water wherein the composition does not contain a glycol ether solvent, an alpha olefin sulfonate surfactant, sodium citrate, a polyoxyalkylene glycol fatty acid, a mono- or di-saccharides, a builder, a polymeric thickener, a clay, a sodium salt of ethylene diamine tetraacetic acid or hydroxyethylene diamine tetra acetic acid abrasive, silicas, triclosan, alkaline earth metal carbonates, alkyl glycine surfactant or cyclic imidinium surfactant.
The C10-C20 paraffin sulfonates can be used at a concentration of 4 wt. % to 16 wt. %, more preferably 6 wt. % to 14 wt. % in the instant compositions may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744 and 3,372,188 and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
The alkyl polysaccharides surfactants, which are used in conjunction with the aforementioned surfactant have a hydrophobic group containing from about 8 to about 20 carbon atoms, preferably from about 10 to about 16 carbon atoms, most preferably from about 12 to about 14 carbon atoms, and polysaccharide hydrophilic group containing from about 1.5 to about 10, preferably from about 1.5 to about 4, most preferably from about 1.6 to about 2.7 saccharide units (e.g., galactoside, glucoside, fructoside, glucosyl, fructosyl; and/or galactosyl units). Mixtures of saccharide moieties may be used in the alkyl polysaccharide surfactants. The number x indicates the number of saccharide units in a particular alkyl polysaccharide surfactant. For a particular alkyl polysaccharide molecule x can only assume integral values. In any physical sample of alkyl polysaccharide surfactants there will be in general molecules having different x values. The physical sample can be characterized by the average value of x and this average value can assume non-integral values. In this specification the values of x are to be understood to be average values. The hydrophobic group (R) can be attached at the 2-, 3-, or 4-positions rather than at the 1-position, (thus giving e.g. a glucosyl or galactosyl as opposed to a glucoside or galactoside). However, attachment through the 1-position, i.e., glucosides, galactoside, fructosides, etc., is preferred. In the preferred product the additional saccharide units are predominately attached to the previous saccharide unit""s 2-position. Attachment through the 3-, 4-, and 6-positions can also occur. Optionally and less desirably there can be a polyalkoxide chain joining the hydrophobic moiety (R) and the polysaccharide chain. The preferred alkoxide moiety is ethoxide.
Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from about 8 to about 20, preferably from about 10 to about 18 carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to 3 hydroxy groups and/or the polyalkoxide chain can contain up to about 30, preferably less than about 10, alkoxide moieties.
Suitable alkyl polysaccharides are decyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, and octadecyl, di-, tri-, tetra-, penta-, and hexaglucosides, galactosides, lactosides, fructosides, fructosyls, lactosyls, glucosyls and/or galactosyls and mixtures thereof.
The alkyl monosaccharides are relatively less soluble in water than the higher alkyl polysaccharides. When used in admixture with alkyl polysaccharides, the alkyl monosaccharides are solubilized to some extent. The use of alkyl monosaccharides in admixture with alkyl polysaccharides is a preferred mode of carrying out the invention. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.
The preferred alkyl polysaccharides are alkyl polyglucosides having the formula
R2O(CnH2nO)r(Z)x
wherein Z is derived from glucose, R is a hydrophobic group selected from the group consisting of alkyl, alkylphenyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl groups contain from about 10 to about 18, preferably from about 12 to about 14 carbon atoms; n is 2 or 3 preferably 2, r is from 0 to 10, preferable 0; and x is from 1.5 to 8, preferably from 1.5 to 4, most preferably from 1.6 to 2.7. To prepare these compounds a long chain alcohol (R2OH) can be reacted with glucose, in the presence of an acid catalyst to form the desired glucoside. Alternatively the alkyl polyglucosides can be prepared by a two step procedure in which a short chain alcohol (R1OH) can be reacted with glucose, in the presence of an acid catalyst to form the desired glucoside. Alternatively the alkyl polyglucosides can be prepared by a two step procedure in which a short chain alcohol (C1-6) is reacted with glucose or a polyglucoside (x=2 to 4) to yield a short chain alkyl glucoside (x=1 to 4) which can in turn be reacted with a longer chain alcohol (R2OH) to displace the short chain alcohol and obtain the desired alkyl polyglucoside. If this two step procedure is used, the short chain alkylglucosde content of the final alkyl polyglucoside material should be less than 50%, preferably less than 10%, more preferably less than about 5%, most preferably 0% of the alkyl polyglucoside.
The amount of unreacted alcohol (the free fatty alcohol content) in the desired alkyl polysaccharide surfactant is preferably less than about 2%, more preferably less than about 0.5% by weight of the total of the alkyl polysaccharide. For some uses it is desirable to have the alkyl monosaccharide content less than about 10%.
The used herein, xe2x80x9calkyl polysaccharide surfactantxe2x80x9d is intended to represent both the preferred glucose and galactose derived surfactants and the less preferred alkyl polysaccharide surfactants. Throughout this specification, xe2x80x9calkyl polyglucosidexe2x80x9d is used to include alkyl polyglycosides because the stereochemistry of the saccharide moiety is changed during the preparation reaction.
An especially preferred APG glycoside surfactant is APG 625 glycoside manufactured by the Henkel Corporation of Ambler, Pa. APG25 is a nonionic alkyl polyglycoside characterized by the formula:
CnH2n+1O(C6H10O5)xH
wherein n=10 (2%); n=122 (65%); n=14 (21-28%); n=16 (4-8%) and n=18 (0.5%) and x (degree of polymerization)=1.6. APG 625 has: a pH of 6 to 10 (10% of APG 625 in distilled water); a specific gravity at 25xc2x0 C. of 1.1 g/ml; a density at 25xc2x0 C. of 9.1 lbs/gallon; a calculated HLB of 12.1 and a Brookfield viscosity at 35xc2x0 C., 21 spindle, 5-10 RPM of 3,000 to 7,000 cps.
The water-soluble zwitterionic surfactant, which can also be used provides good foaming properties and mildness to the present nonionic based liquid detergent. The zwitterionic surfactant is a water soluble betaine having the general formula:
wherein R1 is an alkyl group having 10 to 20 carbon atoms, preferably 12 to 16 carbon atoms, or the amido radical:
wherein R is an alkyl group having 9 to 19 carbon atoms and a is the integer 1 to 4; R2 and R3 are each alkyl groups having 1 to 3 carbons and preferably 1 carbon; R4 is an alkylene or hydroxyalkylene group having from 1 to 4 carbon atoms and, optionally, one hydroxyl group. Typical alkyldimethyl betaines include decyl dimethyl betaine or 2-(N-decyl-N,N-dimethyl-ammonia) acetate, coco dimethyl betaine or 2-(N-coco N,N-dimethylammonio)acetate, myristyl dimethyl betaine, palmityl dimethyl betaine, lauryl diemethyl betaine, cetyl dimethyl betaine, stearyl dimethyl betaine, etc. The amidobetaines similarly include cocoamidoethylbetaine, cocoamidopropyl betaine and the like. A preferred betaine is coco (C8-C18) amidopropyl dimethyl betaine.
Amine oxide semi-polar nonionic surfactants comprise compounds and mixtures of compounds having the formula:
wherein R1 is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from 8 to 18 carbon atoms, R2 and R3 are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl, and n is from 0 to 10. Particularly preferred are amine oxides of the formula:
wherein R1 is a C12-16 alkyl and R2 and R3 are methyl or ethyl. The above ethylene oxide condensates, amides, and amine oxides are more fully described in U.S. Pat. No. 4,316,824 which is hereby incorporated herein by reference.
The instant composition can contain a mixture of a C12-14 alkyl monoalkanol amide such as lauryl monoalkanol amide and a C12-14 alkyl dialkanol amide such as lauryl diethanol amide or coco diethanol amide.
The water soluble nonionic surfactants utilized in this invention are commercially well known and include the primary aliphatic alcohol ethoxylates, secondary aliphatic alcohol ethoxylates, alkylphenol ethoxylates and ethylene-oxide-propylene oxide condensates on primary alkanols, such a Plurafacs (BASF) and condensates of ethylene oxide with sorbitan fatty acid esters such as the Tweens (ICI). The nonionic synthetic organic detergents generally are the condensation products of an organic aliphatic or alkyl aromatic hydrophobic compound and hydrophilic ethylene oxide groups. Practically any hydrophobic compound having a carboxy, hydroxy, amido, or amino group with a free hydrogen attached to the nitrogen or the oxygen can be condensed with ethylene oxide or with the polyhydration product thereof, polyethylene glycol, to form a water-soluble nonionic detergent. Further, the length of the polyethenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.
The nonionic detergent class includes the condensation products of a higher alcohol (e.g., an alkanol containing about 8 to 18 carbon atoms in a straight or branched chain configuration) condensed with about 5 to 30 moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with about 16 moles of ethylene oxide (EO), tridecanol condensed with about 6 to moles of EO, myristyl alcohol condensed with about 10 moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from 10 to about 14 carbon atoms in length and wherein the condensate contains either about 6 moles of EO per mole of total alcohol or about 9 moles of EO per mole of alcohol and tallow alcohol ethoxylates containing 6 EO to 11 EO per mole of alcohol.
A preferred group of the foregoing nonionic surfactants are the Neodol ethoxylates (Shell Co.), which are higher aliphatic, primary alcohol containing about 9-15 carbon atoms, such as C9-C11 alkanol condensed with 7 to 10 moles of ethylene oxide (Neodol 91-8), C12-13 alkanol condensed with 6.5 moles ethylene oxide (Neodol 23-6.5), C12-15 alkanol condensed with 12 moles ethylene oxide (Neodol 25-12), C14-15 alkanol condensed with 13 moles ethylene oxide (Neodol 45-13), and the like. Such ethoxamers have an HLB (hydrophobic lipophilic balance) value of about 8 to 15 and give good O/W emulsification, whereas ethoxamers with HLB values below 8 contain less than 5 ethyleneoxide groups and tend to be poor emulsifiers and poor detergents.
Additional satisfactory water soluble alcohol ethylene oxide condensates are the condensation products of a secondary aliphatic alcohol containing 8 to 18 carbon atoms in a straight or branched chain configuration condensed with 5 to 30 moles of ethylene oxide. Examples of commercially available nonionic detergents of the foregoing type are C11-C15 secondary alkanol condensed with either 9 EO (Tergitol 15-S-9) or 12 EO (Tergitol 15-S-12) marketed by Union Carbide.
Other suitable nonionic detergents include the polyethylene oxide condensates of one mole of alkyl phenol containing from about 8 to 18 carbon atoms in a straight- or branched chain alkyl group with about 5 to 30 moles of ethylene oxide. Specific examples of alkyl phenol ethoxylates include nonyl phenol condensed with about 9.5 moles of EO per mole of nonyl phenol, dinonyl phenol condensed with about 12 moles of EO per mole of phenol, dinonyl phenol condensed with about 15 moles of EO per mole of phenol and di-isoctylphenol condensed with about 15 moles of EO per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-630 (nonyl phenol ethoxylate) marketed by GAF Corporation.
Also among the satisfactory nonionic detergents are the water-soluble condensation products of a C8-C20 alkanol with a heteric mixture of ethylene oxide and propylene oxide wherein the weight ratio of ethylene oxide to propylene oxide is from 2.5:1 to 4:1, preferably 2.8:1 to 3.3:1, with the total of the ethylene oxide and propylene oxide (including the terminal ethanol or propanol group) being from 60-85%, preferably 70-80%, by weight. Such detergents are commercially available from BASF-Wyandotte and a particularly preferred detergent is a C10-C16 alkanol condensate with ethylene oxide and propylene oxide, the weight ratio of ethylene oxide to propylene oxide being 3:1 and the total alkoxy content being about 75% by weight.
Condensates of 2 to 30 moles of ethylene oxide with sorbitan mono- and tri-C10-C20 alkanoic acid esters having a HLB of 8 to 15 also may be employed as the nonionic detergent ingredient in the described composition. These surfactants are well known and are available from Imperial Chemical Industries under the Tween trade name. Suitable surfactants include polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (4) sorbitan monostearate, polyoxyethylene (20) sorbitan trioleate and polyoxyethylene (20) sorbitan tristearate.
Other suitable water-soluble nonionic detergents are marketed under the trade name xe2x80x9cPluronics.xe2x80x9d The compounds are formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The molecular weight of the hydrophobic portion of the molecule is of the order of 950 to 4000 and preferably 200 to 2,500. The addition of polyoxyethylene radicals to the hydrophobic portion tends to increase the solubility of the molecule as a whole so as to make the surfactant water-soluble. The molecular weight of the block polymers varies from 1,000 to 15,000 and the polyethylene oxide content may comprise 20% to 80% by weight. Preferably, these surfactants will be in liquid form and satisfactory surfactants are available as grades L 62 and L 64.
The anionic sulfonate surfactants which may be used in the detergent of this invention are water soluble and include the sodium, potassium, ammonium and ethanolammonium salts of linear C8-C16 alkyl benzene sulfonates; C10-C20 paraffin sulfonates, alpha olefin sulfonates containing about 10-24 carbon atoms and C8-C18 alkyl sulfates and mixtures thereof. The preferred anionic sulfonate surfactant is a C12-18 paraffin sulfonate.
The paraffin sulfonates may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744; and 3,372,188; and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
Examples of suitable other sulfonated anionic detergents are the well known higher alkyl mononuclear aromatic sulfonates, such as the higher alkylbenzene sulfonates containing 9 to 18 or preferably 9 to 16 carbon atoms in the higher alkyl group in a straight or branched chain, or C8-15 alkyl toluene sulfonates. A preferred alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a higher content of 3-phenyl (or higher) isomers and a correspondingly lower content (well below 50%) of 2-phenyl (or lower) isomers, such as those sulfonates wherein the benzene ring is attached mostly at the 3 or higher (for example 4, 5, 6 or 7) position of the alkyl group and the content of the isomers in which the benzene ring is attached in the 2 or 1 position is correspondingly low. Preferred materials are set forth in U.S. Pat. No. 3,320,174, especially those in which the alkyls are of 10 to 13 carbon atoms.
The C8-18 ethoxylated alkyl ether sulfate surfactants have the structure
Rxe2x80x94(OCHCH2)nOSOxe2x88x923M+
wherein n is about 1 to about 22 more preferably 1 to 3 and R is an alkyl group having about 8 to about 18 carbon atoms, more preferably 12 to 15 and natural cuts, for example, C12-14 or C12-16 and M is an ammonium cation or a metal cation, most preferably sodium. The ethoxylated alkyl ether sulfate is present in the composition at a concentration of about 2.0 to about 5.0 wt. %, more preferably about 2.5% to 4.5 wt. %.
The ethoxylated alkyl ether sulfate may be made by sulfating the condensation product of ethylene oxide and C8-10 alkanol, and neutralizing the resultant product. The ethoxylated alkyl ether sulfates differ from one another in the number of carbon atoms in the alcohols and in the number of moles of ethylene oxide reacted with one mole of such alcohol. Preferred ethoxylated alkyl ether polyethenoxy sulfates contain 12 to 15 carbon atoms in the alcohols and in the alkyl groups thereof, e.g., sodium myristyl (3 EO) sulfate.
The instant compositions can contain a solubilizing agent at a concentration of 0.25 to 10 wt. %, more preferably 0.5 wt. % to 8 wt. %. The solubilzing agent is selected from the group consisting of C1-C4 alkanols such as ethanols, alkylene glycols such as hexylene glycol, alkali metal halides such as sodium chloride and sodium salts of C1-C3 alkyl substituted benzene sulfonates such as cumene sulfonate or xylene sulfonate and mixtures thereof. The composition can also contain 0.1 wt. % to 4 wt. % of urea.
The proton donating agent is a hydroxy containing organic acid such as hydroxy benzoic acid, citric acid, lactic acid, glycolic acid, salicylic acid or an inorganic acid and mixtures thereof.
The zinc inorganic can be zinc sulfate or zinc halide such as zinc chloride or zinc bromide, wherein zinc chloride is preferred. The alkali metal inorganic salt is an alkali metal halide, wherein sodium chloride is preferred. The magnesium inorganic salt is either magnesium chloride or magnesium sulfate heptahydrate.
The water is present at a concentration of 50 wt. % to 90 wt. %.
In addition to the previously mentioned essential and optional constituents of the light duty liquid detergent, one may also employ normal and conventional adjuvants, provided they do not adversely affect the properties of the detergent. Thus there may be used a cationic antibacterial agent, coloring agents and perfumes; polyethylene glycol, ultraviolet light absorbers such as the Uvinuls, which are products of GAF Corporation; pH modifiers; etc. The proportion of such adjuvant materials, in total will normally not exceed 15% by weight of the detergent composition, and the percentages of most of such individual components will be a maximum of 5% by weight and preferably less than 2% by weight. Sodium formate or formalin or Quaternium15 (Dowcil75) can be included in the formula as a preservative at a concentration of 0.1 to 4.0 wt. %.
The present light duty liquid detergents such as dishwashing liquids are readily made by simple mixing methods from readily available components which, on storage, do not adversely affect the entire composition. Solubilizing agent such as ethanol, hexylene glycol, sodium chloride and/or sodium xylene or sodium xylene sulfonate are used to assist in solubilizing the surfactants. The viscosity of the light duty liquid composition desirably will be at least 100 centipoises (cps) at room temperature, but may be up to 1,000 centipoises as measured with a Brookfield Viscometer using a number 21 spindle rotating at 20 rpm. The viscosity of the light duty liquid composition may approximate those of commercially acceptable light duty liquid compositions now on the market. The viscosity of the light duty liquid composition and the light duty liquid composition itself remain stable on storage for lengthy periods of time, without color changes or settling out of any insoluble materials. The pH of the composition is about 3 to 8.0. The pH of the composition can be adjusted by the addition of Na2O (caustic soda) to the composition.
The following examples illustrate liquid cleaning compositions of the described invention. Unless otherwise specified, all percentages are by weight. The exemplified compositions are illustrative only and do no limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.

Antibacterial light duty liquid detergent


A thermoplastic composition which may be unvulcanized or vulcanized is provided which comprises a polymer blend of an elastomeric thermoplastic engineering resin and a halogen-containing copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene. A process for preparing a dynamically vulcanized composition is also provided.

1. Field of the Invention
The invention relates to thermoplastic compositions having improved properties and a process for preparing the compositions. Optionally, these blends may be dynamically vulcanized.
2. Description of Information Disclosures
In recent years, there has been a significant commercial interest in polymer blends which have a combination of both elastic and thermoplastic properties. These polymer blends have been given the generic designation of Thermoplastic Olefins (xe2x80x9cTPOxe2x80x9d). They exhibit some of the properties of a cured elastomer as well as the reprocessability of thermoplastic resins. The elastomeric characteristics may be enhanced if one component of the blend is a vulcanizable elastomer which is wholly or partially crosslinked.
U.S. Pat. No. 4,130,534 discloses elastoplastic compositions comprising a blend of a thermoplastic crystalline polyolefin resin and a rubber which may be butyl rubber, chlorobutyl rubber or bromobutyl rubber.
U.S. Pat. No. 4,172,859 discloses a thermoplastic composition containing a polyamide matrix resin and at least one polymer having a specified tensile modulus.
U.S. Pat. No. 4,174,358 discloses a thermoplastic composition containing a polyamide matrix resin and at least one polymer having a specified tensile modulus.
The earliest work in the curing of TPO compositions was by Gessler and Haslett; see U.S. Pat. No. 3,037,954. That patent teaches the concept of xe2x80x9cdynamic curingxe2x80x9d wherein a vulcanizable elastomer is dispersed into a resinous thermoplastic polymer and the elastomer cured while continuously mixing and shearing the polymer blend. The result is a micro-gel dispersion of cured rubber in an uncured matrix of resinous thermoplastic polymer. Gessler""s U.S. Pat. No. 3,037,954 discloses compositions comprising polypropylene and a rubber wherein the rubber may be, butyl rubber, chlorinated butyl rubber, polybutadiene, polychloroprene and polyisobutene. Compositions of about 50 to 95 parts polypropylene and about 5 to 50 parts of rubber are disclosed.
U.S. Pat. No. 4,639,487 discloses a heat shrinkable thermoplastic composition of an ethylene copolymer resin with a dynamically vulcanized halogenated butyl rubber.
Dynamically vulcanized thermoplastic compositions comprising a polyamide and various types of elastomers are known. See, for example, U.S. Pat. No. 4,173,556; U.S. Pat. No. 4,197,379; U.S. Pat. No. 4,207,404; U.S. Pat. No. 4,297,453; U.S. Pat. No. 4,338,413; U.S. Pat. No. 4,348,502; and U.S. Pat. No. 4,419,499.
U.S. Pat. No. 4,287,324 discloses a dynamically vulcanized composition comprising a blend of a crystalline polyester and a cured epichlorohydrin.
U.S. Pat. No. 4,226,953 discloses a dynamically vulcanized composition comprising a blend of styrene-acrylonitrile resin and a nitrile rubber.
U.S. Pat. No. 4,350,794 discloses a polyamide molding and extrusion composition prepared by melt blending a polyamide resin and a polyamide reactive halogen functional elastomer.
There is still a need to improve the properties of uncured and of dynamically vulcanized alloys.
It has now been found that compositions comprising a thermoplastic engineering resin and a halogen-containing copolymer of an isoolefin and a para-alkylstyrene have improved properties, such as higher Vicat softening temperature, lower oil absorption, resistance to compression set, and retention of properties after heat aging. Moreover, these compositions may be stabilized to ultraviolet light exposure without adversely affecting their properties. The compositions may also comprise uncured or dynamically cured elastomers.
In accordance with one embodiment of the invention, there is provided a thermoplastic composition comprising a polymer blend of a thermoplastic engineering resin, and an elastomeric halogen-containing copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene.
In accordance with an other embodiment of the invention, there is provided a thermoplastic composition comprising a vulcanized polymer blend of a thermoplastic engineering resin, and an elastomeric halogen-containing copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene.
The thermoplastic composition of the present invention comprises a blend of a thermoplastic engineering resin, and an elastomeric halogen-containing copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene which may be an unvulcanized composition or which may be statically vulcanized or which may have been subjected to dynamic vulcanization.
The term xe2x80x9cdynamic vulcanizationxe2x80x9d is used herein to connote a vulcanization process in which the engineering resin and a vulcanizable elastomer are vulcanized under conditions of high shear. As a result, the vulcanizable elastomer is simultaneously crosslinked and dispersed as fine particles of a xe2x80x9cmicro gelxe2x80x9d within the engineering resin matrix.
Dynamic vulcanization is effected by mixing the ingredients at a temperature which is at or above the curing temperature of the elastomer in equipment such as roll mills, Banbury(copyright) mixers, continuous mixers, kneaders or mixing extruders, e.g., twin screw extruders. The unique characteristic of the dynamically cured compositions is that, notwithstanding the fact that the elastomer component may be fully cured, the compositions can be processed and reprocessed by conventional rubber processing techniques such as extrusion, injection molding, compression molding, etc. Scrap or flashing can be salvaged and reprocessed.
In the embodiment of the invention in which it is desired to obtain dynamically vulcanized alloys (DVA""s) the alloys are generally prepared by blending together at least one engineering resin and at least one elastomer with curatives and fillers under conditions of dynamic vulcanization.
In preparing the preferred dynamically vulcanized composition of the present invention, at least a portion of one thermoplastic engineering resin is blended with the elastomeric halogen-containing copolymer.
The thermoplastic engineering resins suitable for practice of the present invention may be used singly or in combination and are resins containing nitrogen, oxygen, halogen, sulfur or other groups capable of interacting with an aromatic haloalkyl group. Suitable engineering resins include resins selected from the group consisting of polyamides, polycarbonates, polyesters, polysulfones, polylactones, polyacetals, acrylonitrile-butadiene-styrene resins (ABS), polyphenyleneoxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile resins (SAN), polyimides, styrene maleic anhydride (SMA), aromatic polyketones (PEEK, PEK, and PEKK) and mixtures thereof. Preferred thermoplastic engineering resins are polyamides. The more preferred polyamides are nylon 6 and nylon 11.
Suitable thermoplastic polyamides (nylons) comprise crystalline or resinous, high molecular weight solid polymers including copolymers and terpolymers having recurring amide units within the polymer chain. Polyamides may be prepared by polymerization of one or more epsilon lactams such as caprolactam, pyrrolidione, lauryllactam and aminoundecanoic lactam, or amino acid, or by condensation of dibasic acids and diamines. Both fiber-forming and molding grade nylons are suitable. Examples of such polyamides are polycaprolactam (nylon-6), polylauryllactam (nylon-12), polyhexamethyleneadipamide (nylon-6,6), polyhexamethyleneazelamide (nylon-6,9), polyhexamethylenesebacamide (nylon-6,10), polyhexamethyleneisophthalamide (nylon-6,IP) and the condensation product of 11-aminoundecanoic acid (nylon-11). Additional examples of satisfactory polyamides (especially those having a softening point below 275xc2x0 C.) are described in Kirk-Othmer, Encyclopedia of Chemical Technology, v. 10, page 919, and Encyclopedia of Polymer Science and Technology, Vol. 10, pages 392-414. Commercially available thermoplastic polyamides may be advantageously used in the practice of this invention, with linear crystalline polyamides having a softening point or melting point between 160xc2x0-230xc2x0 C. being preferred.
Suitable thermoplastic polyesters comprise linear, crystalline, high molecular weight solid polymers having recurring
groups including
groups within the polymer chain. The term xe2x80x9clinearxe2x80x9d as used herein in respect to polyester means a polymer in which the recurring ester groups are within the polymer backbone and not pendant therefrom. Linear crystalline polyesters having a softening point above about 50xc2x0 C. are satisfactory, with polyesters having a softening point or melting point above being preferred, with polyesters having a softening point or melting point between 160xc2x0-260xc2x0 C. being more preferred. Saturated linear polyesters (free of olefinic unsaturation) are preferred, however, unsaturated polyesters may be used provided that the rubber, if cross-linked, is cross-linked prior to blending with the polyester or provided that the rubber is dynamically cross-linked with a cross-linking agent that will not significantly induce cross-link formation in the polyester. Cross-linked polyesters are unsatisfactory for the practice of this invention. If significant cross-link formation of the polyester is permitted to occur, the resulting composition is not thermoplastic. Many commercially available thermoplastic linear crystalline polyesters may be advantageously employed in the practice of the invention or they may be prepared by polymerization of one or more dicarboxylic acids, anhydrides or esters and one or more diol. Examples of satisfactory polyesters include poly(trans-1,4-cyclohexylene C2-6 alkane dicarboxylates such as poly(trans-1,4-cyclohexylene succinate) and poly(trans-1,4-cyclohexylene adipate), poly(cis or trans-1,4-cyclohexanedimethylene) C0-2 alkanedicarboxylates such as poly(cis 1,4-cyclohexane-di-methylene)oxalate and poly-(cis 1,4-cyclohexane-di-methylene) succinate, poly(C2-4 alkylene terephthalates) such as polyethyleneterephthalate and polytetramethylene-terephthalate, poly(C2-4 alkylene terephthalates) such as polyethyleneterephthalate and polytetramethylene-terephthalate, poly(C2-4 alkylene isophthalates such as polyethyleneisophthalate and polytetramethylene-isophthalate, poly(p-phenylene C1-3 alkanedicarboxylates such as poly(p-phenylene glutarate) and poly(p-phenylene adipate), poly(p-xylene oxalate), poly(o-xylene oxalate), poly(p-phenylenedi-C1-5 alkylene terephthalates) such as poly(p-phenylenedimethylene terephthalate) and poly(p-phenylene-di-1,4-butylene terephthalate, poly-(C2-10 alkylene 1,2-ethylenedioxy-4,4-dibenzoates) such as poly(ethylene-1,2-ethylenedioxy-4,4-dibenzoates), poly-(tetramethylene-1,2-ethylenedioxy-4,4-dibenzoate) and poly-(hexamethylene-1,2-ethylene-dioxy-4,4-dibenzoate), poly(C3-10 alkylene-4,4-dibenzoates) such as poly(pentamethylene-4,4-dibenzoate), poly(hexamethylene-4,4-dibenzoate and poly(decamethylene-4,4-dibenzoate), poly(C2-10 alkylene-2,6-naphthalene dicarboxylates) such as poly-(ethylene-2,6-naphthalene dicarboxylates) poly(trimethylene-26-naphthalene dicarboxylates) and poly(tetramethylene-2,6-naphthalene dicarboxylates), and poly-(C2-10 alkylene sulfonyl-4,4-dibenzoates) such as poly(octamethylene sulfonyl-4,4-dibenzoate) and poly(decamethylene sulfonyl-4,4-dibenzoate. Addtional examples of satisfactory linear polyesters are described in Encyclopedia of Polymer Science and Technology, Vol. 11, pages 68-73 and Korshak and Vinogradova Polyesters, Pergamon Press, pages 31-64. The disclosures thereof are hereby incorporated herein by reference. Suitable polycarbonates are also commercially available. For suitable segmented poly(ether-co-phthalates) see page 46, rubber World Blue Book, supra. Polylactones such as polycaprolactone are satisfactory in the practice of the invention. Preferred polyesters of the invention are derived from aromatic dicarboxylic acids such as naphthalenic or phthalic acids. More preferred polyesters are poly(alkylene terephthalates) especially polytetramethylene terephthalate), or mixed polyphthalates derived from two or more glycols, two or more phthalic acids, or two or more glycols and two or more phthalic acids such as poly(alkylene terecoisophthalates).
Optionally, other thermoplastic polymers, such as polyolefin resins may be included in the polymer blend, such as, for example, PP, HDPE, LDPE, LLDPE, EVA, EMA, etc.
Suitable halogen-containing copolymers of a C4 to C7 isomonoolefin and a para-alkylstyrene for use as a component of the composition of the present invention comprise at least about 0.5 weight percent of the para-alkylstyrene moiety. For elastomeric copolymers, the para-alkylstyrene moiety may range from about 0.5 weight percent to about 25 weight percent, preferably from about 1 to about 20 weight percent, more preferably from about 2 to about 20 weight percent of the copolymer. The halogen content of the copolymers may range from above zero to about 10 weight percent, preferably from about 0.1 to about 7 weight percent. The halogen may be bromine, chlorine, and mixtures thereof. Preferably, the halogen is bromine. The major portion of the halogen is chemically bound to the para-alkyl group, that is, the halogen-containing copolymer comprises para-haloalkyl groups.
The copolymers of the isomonoolefin and para-alkylstyrene useful to prepare the halogen-containing copolymers suitable as components of the composition of the present invention include copolymers of isomonoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene, such as those described in European patent application 89305395.9 filed May 26, 1989, (Publication No. 0344021 published Nov. 29, 1989). The preferred isomonoolefin comprises isobutylene. The preferred para-alkylstyrene comprises para-methylstyrene. Suitable copolymers of an isomonoolefin and a para-alkylstyrene include copolymers having a number average molecular weight ({overscore (M)}n) of at least about 25,000, preferably at least about 30,000, more preferably at least about 100,000. The copolymers also, preferably, have a ratio of weight average molecular weight ({overscore (M)}w) to number average molecular weight ({overscore (M)}n), i.e., {overscore (M)}w/{overscore (M)}n of less than about 6, preferably less than about 4, more preferably less than about 2.5, most preferably less than about 2. The brominated copolymer of the isoolefin and para-alkylstyrene by the polymerization of these particular monomers under certain specific polymerization conditions now permit one to produce copolymers which comprise the direct reaction product (that is, in their as-polymerized form), and which have unexpectedly homogeneous uniform compositional distributions. Thus, by utilizing the polymerization and bromination procedures set forth herein, the copolymers suitable for the practice of the present invention can be produced. These copolymers, as determined by gel permeation chromatography (GPC) demonstrate narrow molecular weight distributions and substantially homogeneous compositional distributions, or compositional uniformity over the entire range of compositions thereof. At least about 95 weight percent of the copolymer product has a para-alkylstyrene content within about 10 weight percent, and preferably within about 7 weight percent, of the average para-alkylstyrene content for the overall composition, and preferably at least about 97 weight percent of the copolymer product has a para-alkylstyrene content within about 10 weight percent and preferably within about 7 weight percent, of the average para-alkylstyrene content for the overall composition. This substantially homogeneous compositional uniformity thus particularly relates to the intercompositional distribution. That is, with the specified copolymers, as between any selected molecular weight fraction the percentage of para-alkylstyrene therein, or the ratio of para-alkylstyrene to isoolefin, will be substantially the same, in the manner set forth above.
In addition, since the relative reactivity of an isoolefin such as isobutylene with para-alkylstyrene is close to one, the compositional distribution of these copolymers will also be substantially homogeneous. That is, these copolymers are essentially random copolymers, and in any particular polymer chain the para-alkylstyrene and isoolefin units will be essentially randomly distributed throughout that chain.
The halogen-containing copolymers useful in the practice of the present invention have a substantially homogeneous compositional distribution and include the para-alkylstyrene moiety represented by the formula:
in which R and R1 are independently selected from the group consisting of hydrogen, alkyl preferably having from 1 to 5 carbon atoms, primary haloalkyl, secondary haloalkyl, preferably having from 1 to 5 carbon atoms, and mixtures thereof and X is selected from the group consisting of bromine, chlorine and mixtures thereof, such as those disclosed in European patent application 8930595.9 filed May 26, 1989, (Publication No. 0344021 published Nov. 29, 1989).
Various methods may be used to produce the copolymers of isomonoolefin and para-alkylstyrene, as described in said European publication. Preferably, the polymerization is carried out continuously in a typical continuous polymerization process using a baffled tank-type reactor fitted with an efficient agitation means, such as a turbo mixer or propeller, and draft tube, external cooling jacket and internal cooling coils or other means of removing the heat of polymerization, inlet pipes for monomers, catalysts and diluents, temperature sensing means and an effluent overflow to a holding drum or quench tank. The reactor is purged of air and moisture and charged with dry, purified solvent or a mixture of solvents prior to introducing monomers and catalysts.
Reactors which are typically used in butyl rubber polymerization are generally suitable for use in a polymerization reaction to produce the desired para-alkyl-styrene copolymers suitable for use in the process of the present invention. The polymerization temperature may range from about minus 35xc2x0 C. to about minus 100xc2x0 C., preferably from about minus 40 to about minus 95xc2x0 C.
The processes for producing the copolymers can be carried out in the form of a slurry of polymer formed in the diluents employed, or as a homogeneous solution process. The use of a slurry process is, however, preferred, since in that case, lower viscosity mixtures are produced in the reactor and slurry concentration of up to 40 wt. percent of polymer are possible.
The copolymers of isomonoolefins and para-alkyl-styrene may be produced by admixing the isomonoolefin and the para-alkylstyrene in a copolymerization reactor under copolymerization conditions in the presence of a diluent and a Lewis acid catalyst.
Typical examples of the diluents which may be used alone or in a mixture include propane, butane, pentane, cyclopentane, hexane, toluene, heptane, isooctane, etc., and various halohydrocarbon solvents which are particularly advantageous herein, including methylene chloride, chloroform, carbon tetrachloride, methyl chloride, with methyl chloride being particularly preferred.
An important element in producing the copolymer is the exclusion of impurities from the polymerization reactor, namely, impurities which, if present, will result in catalyst poisoning or excessive molecular weight depression by complexing with the catalyst or copolymerization with the isomonoolefins or the para-alkylstyrene, which in turn will prevent one from efficiently producing the para-alkylstyrene copolymer product useful in the practice of the present invention. Most particularly, these impurities include the catalyst poisoning materials, such as, for example. moisture and the like and other copolym-erizable monomers, such as, for example, meta-alkylstyrenes and the like. These impurities should be kept out of the system.
In producing the suitable copolymers, it is preferred that the para-alkylstyrene be at least 95.0 wt. percent pure, preferably 97.5 wt. percent pure, most preferably 99.5 wt. percent pure and that the isomonoolefin be at least 99.5 wt. percent pure, preferably at least 99.8 wt. percent pure and that the diluents employed be at least 99 wt. percent pure, and preferably at least 99.8 wt. percent pure.
The most preferred Lewis acid catalysts are ethyl aluminum dichloride and preferably mixtures of ethyl aluminum dichloride with diethyl aluminum chloride. The amount of such catalysts employed will depend on the desired molecular weight and the desired molecular weight distribution of the copolymer being produced, but will generally range from about 20 ppm to 1 wt. percent and preferably from about 0.01 to 0.2 wt. percent, based upon the total amount of monomer to be polymerized.
Halogenation of the polymer can be carried out in the bulk phase (e.g., melt phase) or either in solution or in a finely dispersed slurry. Bulk halogenation can be effected in an extruder, or other internal mixer, suitably modified to provide adequate mixing and for handling the halogen and corrosive by-products of the reaction. The details of such bulk halogenation processes are set forth in U.S. Pat. No. 4,548,995, which is hereby incorporated by reference.
Suitable solvents for solution halogenation include the low boiling hydrocarbons (C4 to C7) and halogenated hydrocarbons. Since the high boiling point of para-methylstyrene makes its removal by conventional distillation impractical, and since it is difficult to completely avoid solvent halogenation, it is very important where solution or slurry halogenation is to be used that the diluent and halogenation conditions be chosen to avoid diluent halogenation, and that residual para-methylstyrene has been reduced to an acceptable level.
It should be noted that radical bromination of the enchained para-methylstyryl moiety in the copolymers useful for the practice of this invention can be made highly specific with almost exclusive substitution occurring on the para-methyl group, to yield the desired benzylic bromine functionality. The high specificity of the bromination reaction can thus be maintained over a broad range of reaction conditions, provided, however, that factors which would promote the ionic reaction route are avoided (i.e., polar diluents, Friedel-Crafts catalysts, etc.).
Thus, solutions of the suitable para-methyl-styrene/isobutylene copolymers in hydrocarbon solvents such as pentane, hexane, heptane or cyclohexane can be selectively brominated using light, heat, or selected radical initiators (according to conditions, i.e., a particular radical initiator must be selected which has an appropriate half-life for the particular temperature conditions being utilized, with generally longer half-lives preferred at warmer halogenation temperatures) as promoters of radical halogenation, to yield almost exclusively the desired benzylic bromine functionality, via substitution on the para-methyl group, and without appreciable chain scission and/or cross-linking.
This reaction can be initiated by formation of a bromine atom, either photochemically or thermally (with or without the use of sensitizers), or the radical initiator used can be one which preferentially reacts with a bromine molecule rather than one which reacts indiscriminately with bromine atoms, or with the solvent or polymer (i.e., via hydrogen abstraction). The sensitizers referred to are those photochemical sensitizers which will themselves absorb lower energy photons and disassociate, thus causing, in turn, disassociation of the bromine, including materials such as iodine. It is, thus, preferred to utilize an initiator which has a half life of between about 0.5 and 2500 minutes under the desired reaction conditions, more preferably about 10 to 300 minutes. The amount of initiator employed will usually vary between 0.02 and 1 percent by weight on the copolymer, preferably between about 0.02 and 0.3 percent. The preferred initiators are bis-azo compounds, such as azobis isobutyronitrile (AIBN), azobis (2,4-dimethylvalero) nitrile, azobis (2-methylbutyro) nitrile, and the like. Other radical initiators can also be used, but it is preferred to use a radical initiator which is relatively poor at hydrogen abstraction, so that it reacts preferentially with the bromine molecules to form bromine atoms rather than with the copolymer or solvent to form alkyl radicals. In those cases, there would then tend to be resultant copolymer molecular weight loss, and promotion of undesirable side reactions, such as cross-linking. The radical bromination reaction of the copolymers of para-methylstyrene and isobutylene can be highly selective under appropriate conditions, and almost exclusively produces the desired benzylic bromine functionality. Indeed, the only major side reaction which appears to occur is disubstitution at the para-methyl group, to yield the dibromo derivative, but even this does not occur until more than about 60 percent of the enchained para-methylstyryl moieties have been monosubstituted. Hence, any desired amount of benzylic bromine functionality in the monobromo form can be introduced into the above stated copolymers, up to about 60 mole percent of the para-methylstyrene content.
It is desirable that the termination reactions be minimized during bromination, so that long, rapid radical chain reactions occur, and so that many benzylic bromines are introduced for each initiation, with a minimum of the side reactions resulting from termination. Hence, system purity is important, and steady-state radical concentrations must be kept low enough to avoid extensive recombination and possible cross-linking. The reaction must also be quenched once the bromine is consumed, so that continued radical production with resultant secondary reactions (in the absence of bromine) do not then occur. Quenching may be accomplished by cooling, turning off the light source, adding dilute caustic, the addition of a radical trap, or combinations thereof.
Since one mole of HBr is produced for each mole of bromine reacted with or substituted on the enchained para-methylstyryl moiety, it is also desirable to neutralize or otherwise remove this HBr during the reaction, or at least during polymer recovery in order to prevent it from becoming involved in or catalyzing undesirable side reactions. Such neutralization and removal can be accomplished with a post-reaction caustic wash, generally using a molar excess of caustic on the HBr. Alternatively, neutralization can be accomplished by having a particulate base (which is relatively non-reactive with bromine) such as calcium carbonate powder present in dispersed form during the bromination reaction to absorb the HBr as it is produced. Removal of the HBr can also be accomplished by stripping with an inert gas (e.g., N2) preferably at elevated temperatures.
The brominated, quenched, and neutralized para-methylstyrene/isobutylene copolymers can be recovered and finished using conventional means with appropriate stabilizers being added to yield highly desirable and versatile functional saturated copolymers.
In summary, halogenation to produce a copolymer useful as a component of the composition of the present invention is preferably accomplished by halogenating an isobutylene-para-methylstyrene copolymer using bromine in a normal alkane (e.g., hexane or heptane) solution utilizing a bis azo initiator, e.g., AIBN or VAZO(copyright) 52: 2, 2xe2x80x2-azobis-(2,4-dimethylpentane nitrile), at about 55 to 80xc2x0 C., for a time period ranging from about 4.5 to about 30 minutes, followed by a caustic quench. The recovered polymer is washed in basic water wash and water/isopropanol washes, recovered, stabilized and dried.
Since little, if any, tertiary benzylic bromine is produced in the molecule (when the halogenation agent is a brominating agent), the potential dehydrohalogenation reaction will be almost entirely eliminated. This results in a halogenated polymer with the improved stability needed for processing at the high temperatures required for melt mixing and processing with engineering resins.
The aromatic haloalkyl group, e.g. the halomethyl group, permits facile crosslinking to be accomplished in a variety of ways, for example, either directly through the halomethyl group or by conversion to other functional groups, to permit the desired crosslinking reations to be employed. Direct crosslinking can be effected with a variety of polyfunctional nucleophilic reagents such as ammonia, amine, polyamines; metal dicarboxylates, metal dithiolates; promoted metal oxides (i.e., ZnO+dithiocarbamates), etc. Crosslinking can also be effected via polyalkylation reactions. The aromatic halomethyl groups thus provide a wide choice of crosslinking reactions to be used that are compatible with the requirements for dynamic vulcanization in a melt mix with the engineering resin component of the present invention.
In the compositions of the present invention, the thermoplastic engineering resin(s) may suitably be present in an amount ranging from about 10 to 98 weight percent, preferably from about 20 to 95 weight percent, the elastomeric halogen-containing copolymer of an isomonoolefin and a para-alkylstyrene may be present in an amount ranging from about 2 to 90 weight percent, preferably from about 5 to 80 weight percent, based on the polymer blend.
The term xe2x80x9cpolymer blendxe2x80x9d is used herein to denote the blend of one or more thermoplastic engineering resins, the elastomeric halogen-containing copolymer and any other polymers (elastomer or non-elastomer) that may be a component of the composition. Optionally, additional elastomers and/or non-elastomeric polymers may be included in the composition of the present invention.
The secant flexural modulus of the thermoplastic compositions may range from about 100 kg/cm2 to about 400,000 kg/cm2, preferably from about 200 kg/cm2 to about 100,000 kg/cm2 measured according to ASTM D790 at 1% strain.
A preferred thermoplastic composition of the invention comprises a polyamide such as nylon.
The polymer blend may comprise about 25 to about 98 wt. percent of the overall composition. In addition to its polymer components, the composition of the present invention may comprise fillers, and additives such as antioxidants, stabilizers, rubber processing oils lubricants (e.g., oleamide), antiblocking agents, waxes, foaming agents, flame retardants, pigments, coupling agents for the fillers and other processing aids known to the rubber compounding art. Metal oxides, e.g., MgO, can be included to act as acid acceptors. The pigments and fillers may comprise up to 30 wt. percent of the total composition based on polymer components plus additives. Preferably, the pigments and fillers comprise about 1 to about 30 wt. percent based on the composition, more preferably about 2 to about 20 weight percent of the overall composition.
Suitable fillers include talc, calcium carbonate, glass fibers, clays, silica, carbon black and mixtures thereof. Any type of carbon black can be used, such as channel blacks, furnace blacks, thermal blacks, acetylene black, lamp black and the like. Titanium dioxide, also considered a pigment, can be used to impart a white color to the final product.
Rubber process oils have particular ASTM designations depending on whether they fall into the class of paraffinic, naphthenic or aromatic process oils. The type of process oil utilized will be that customarily used in conjunction with the rubber component. The skilled rubber chemist will recognize which type of oil should be utilized with a particular rubber. The quantity of rubber process oil utilized is based on the total rubber content, and can be defined as the ratio, by weight, of process oil to the rubber in the composition. This ratio can vary from about 0.3/1 to about 1.3/1; preferably about 0.5/1 to about 1.2/1; more preferably about 0.8/1 to about 1.1/1. Oils other than petroleum based oils such as oils derived from coal tar and pine tar can also be utilized. In addition to the petroleum derived rubber process oils, organic esters and other synthetic plasticizers can be used. As used herein, the term xe2x80x9cprocess oilxe2x80x9d means both the petroleum derived process oils and synthetic plasticizers.
The process oil may be included in the composition to insure that the composition has good flow properties. The quantity of oil utilized will depend in part on the amount of polymer blend and filler used as well as, to some extent, the type of cure system utilized. Generally, the process oil, when included, may comprise about 30 wt. percent of the composition. Larger amounts of process oil can be used, the deficit being reduced physical strength.
Antioxidants may be utilized in the composition of this invention to enhance further the improved aging properties of the elastomeric copolymers component of the present invention and to protect the engineering resins. The particular antioxidant utilized will depend on the rubbers and plastics utilized and more than one type may be required. Their proper selection is well within the skill of the rubber chemist. Antioxidants will generally fall into the class of chemical protectors or physical protectants. Physical protectants are used where there is to be little movement in the part to be manufactured from the composition. These are generally waxy materials which impart a xe2x80x9cbloomxe2x80x9d to the surface of the rubber part and form a protective coating or shield the part from oxygen, ozone, etc.
The chemical protectors generally fall into three chemical groups: secondary amines, phenolics and phosphites. Illustrative, non-limiting examples of types of antioxidants useful in the practice of this invention are hindered phenols, amino phenols, hydroquinones, alkyldiamines, amine condensation products, etc. Nonlimiting examples of these and other types of antioxidants are styrenated phenol; 2,2xe2x80x2-methylene-bis-(4-methyl-6-1, butylphenol); 2,6xe2x80x2-di-t-butyl-o-dimethylamino-p-cresol; hydroquinone monobenzyl ether, octylated diphenyl amine, phenyl-beta-naphthlylamine; N,Nxe2x80x2-diphenylethylene diamine; aldol-alpha-naphthylamine; N,Nxe2x80x2-di-phenyl-p-phenylene diamine, etc. The physical antioxidants include mixed petroleum waxes and microcrystalline waxes.
It is within the scope of this invention to incorporate an uncured rubber in combination with a dynamically vulcanized rubber in the composition. This can be accomplished by selecting as the uncured rubber a rubber which cannot be vulcanized by the vulcanizing agent used to cure the elastomeric halogenated copolymer component of the present invention which is to be dynamically vulcanized or by adding to the dynamically vulcanized thermoplastic composition, after the vulcanization agent has been fully consumed, a rubber which is vulcanizable by the vulcanization agent used to vulcanize the elastomeric halogenated copolymer component of the present invention. For example, when the elastomeric halogenated component of the present invention is vulcanized with a cure system which comprises zinc oxide, any other rubber which requires sulfur or another curative to vulcanize it or which is not vulcanizable can be included. Such rubbers include ethylene-propylene polymers (EPM), ethylene-propylene-diene polymers (EPDM), polyisobutylene, natural rubber, etc. Alternatively, the DVA can be prepared first from the resin and vulcanizable elastomer by dynamic vulcanization and subsequently, an uncured rubber can be blended into the DVA at a temperature above the melting point of the thermoplastic resin. In the embodiment in which an uncured rubber is incorporated in the dynamically vulcanized composition, the uncured rubber may be present in an amount ranging from above zero to about 25, preferably from about 5 to about 20 weight percent of the total rubber (i.e., elastomer) content of the composition.
When it is desired to produce a vulcanized composition, any conventional curative system which is capable of vulcanizing saturated halogenated polymers may be used to vulcanize at least the elastomeric halogenated copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene, except that peroxide curatives are specifically excluded from the practice of this invention when the thermoplastic engineering resins chosen as components are such that peroxide would cause these thermoplastic resins themselves to crosslink. Furthermore, any curative which would cause the particular engineering resin being used to crosslink under the processing conditions being used to prepare the dynamically vulcanized alloy should be excluded from the curative system used. Suitable curative systems for the elastomeric halogenated copolymer component of the present invention include zinc oxide in combination with zinc stearate or stearic acid and, optionally, one or more of the following accelerators or vulcanizing agents: Permalux (di-ortho-tolylguanidine salt of dicatechol borate), HVA-2 (m-phenylene bis maleimide), Zisnet (2,4,6-trimercapto-5-triazine), ZDEDC (zinc diethyl dithiocarbamate) and other dithiocarbamates, Tetrone A (dipenta-methylene thiuram hexasulfide), Vultac-5 (alkylated phenol disulfide), SP1045 (phenol formaldehyde resin), SP1056 (brominated alkyl phenol formaldehyde resin), DPPD (diphenyl phenylene diamine), salicyclic acid (o-hydroxy benzoic acid), wood rosin (abietic acid), and TMTDS (tetramethyl thiuram disulfide) in combination with sulfur.
The vulcanization is conducted at conditions to vulcanize at least partially, preferably fully, the halogenated elastomeric copolymer.
In the practice of this invention, the engineering resin, the elastomeric copolymer and optional other polymers are mixed together at a temperature sufficient to soften the resin or, more commonly, at a temperature above its melting point when the resin is crystalline at room temperature. If the mixture is to be dynamically vulcanized, after the resin and other polymers have been intimately mixed, the curative or curatives are added. Heating and masticating at vulcanization temperatures are generally adequate to complete vulcanization in about 0.5 to about 10 minutes. The vulcanization time can be reduced by elevating the temperature of vulcanization. A suitable range of vulcanization temperatures is from about the melting point of the matrix resin to about 300xc2x0 C.; more typically, the temperature may range from about the melting point of the matrix resin to about 275xc2x0 C. Preferably the vulcanization is carried out at a temperature range from about the flux temperature of the polymer blend to about 20xc2x0 C. above the softening or melting temperature of the matrix resin.
It is preferred that the mixing process be continued until the desired level of vulcanization is completed. If vulcanization is permitted to continue after mixing has stopped, the composition may not be reprocessable as a thermoplastic. However, the dynamic vulcanization can be carried out in stages. For example, vulcanization can be commenced in a twin screw extruder and pellets formed of the DVA material using an underwater pelletizer thereby quenching the vulcanization before it is completed. It can be completed at a later time under dynamic vulcanization conditions. Those skilled in the art will appreciate the appropriate quantities, types of curatives and extent of mixing time required to carry out the vulcanization of the rubber. Where necessary the rubber alone can be vulcanized using varying amounts of curative to determine the optimum cure system to be utilized and the appropriate cure conditions to achieve a full cure.
While it is preferred that all components be present in the mix prior to carrying out the dynamic vulcanization process of this invention, this is not a necessary condition. For example, in one embodiment, the elastomer to be cured can be dynamically vulcanized in the presence of a portion or all of the engineering resin. This blend can then be let down into additional engineering resin. Similarly, it is not necessary to add all of the fillers and oil prior to dynamic vulcanization. A portion or all of the additives, fillers and oil can be added during or after the vulcanization is completed. Certain ingredients, such as stabilizers and process aids function more effectively if they are added after curing.
The term xe2x80x9crubberxe2x80x9d is used herein interchangeably with xe2x80x9celastomerxe2x80x9d.
The term xe2x80x9cfully vulcanizedxe2x80x9d as used herein with respect to the dynamically vulcanized rubber components of this invention means that the rubber components to be vulcanized have been cured to a state in which the physical properties of the rubber are developed to impart elastomeric properties to the rubber generally associated with the rubbers in their conventionally vulcanized state. The degree of cure of the vulcanized rubber can be described in terms of gel content or conversely extractable components. Alternatively, the degree of cure can be expressed in terms of cross-link density.
Where the determination of extractables is an appropriate measure of the state of cure, the improved thermoplastic elastomeric compositions are produced by vulcanizing the curable rubber components of the blends to the extent that they contain no more than about four percent by weight of the cured rubber components extractable at room temperature by a solvent which dissolves the rubbers which are intended to be vulcanized, and preferably to the extent that the composition contains less than two percent by weight extractable. In general, the less extractables of the cured rubber components, the better are the properties and still more preferable are compositions comprising essentially no extractable rubber from the cured rubber phase (less than 0.5 weight percent). Gel content reported as percent gel is determined by a procedure which comprises determining the amount of insoluble polymer by soaking the specimen for 48 hours in organic solvent at room temperature and weighing the dried residue and making suitable corrections based upon knowledge of the composition. Thus, corrected initial and final weights are obtained by subtracting from the initial weight, the weight of soluble components, other than the rubber to be vulcanized, such as extender oils, plasticizers and components of the composition soluble in organic solvent as well as that of any rubber component, if optionally present, of the DVA which is not intended to be cured. Any insoluble pigments, fillers, etc., are subtracted from both the initial and final weights.
To employ cross-link density as the measure of the state of cure which characterizes the improved thermoplastic elastomeric compositions, the blends are vulcanized to the extent which corresponds to vulcanizing the same rubber as in the blend statically cured under pressure in a mold with such amounts of the same curatives as in the blend and under such conditions of time and temperature to give an effective cross-link density greater than about 3xc3x9710xe2x88x925 moles per milliliter of rubber and preferably greater than about 5xc3x9710xe2x88x925 or even more preferably 1xc3x9710xe2x88x924 moles per milliliter of rubber. The blend is then dynamically vulcanized under similar conditions with the same amount of curative based on the rubber content of the blend as was required for the rubber alone. The cross-link density so determined may be regarded as a measure of the amount of vulcanization which gives the improved thermoplastics. However, it should not be assumed, from the fact that the amount of curative is based on the rubber content of the blend and is that amount which gives the rubber alone the aforesaid cross-link density, that the curative does not react with the resin or that there is no reaction between the resin and rubber. There may be highly significant reactions involved but of limited extent. However, the assumption that the crosslink density determined as described provides a useful approximation of the cross-link density of the thermoplastic elastomeric compositions is consistent with the thermoplastic properties and with the fact that a large proportion of the resin can be removed from the composition by high temperature solvent extraction, with an appropriate solvent for the resin being used.
The cross-link density of the rubber is determined by equilibrium solvent swelling using the Flory-Rehner equation, as shown in J. Rubber Chem. and Tech. 30, p. 929. The appropriate Huggins solubility parameters for rubber solvent pairs used in the calculation were obtained from the review article by Sheehan and Bisio, J. Rubber Chem. and Tech. 39, 149. If the extracted gel content of the vulcanized rubber is low, it is necessary to use the correction of Bueche wherein the term v is multiplied by the gel fraction (% gel/100). The cross-link density is half the effective network chain density v determined in the absence of resin. The cross-link density of the vulcanized blends will, therefore, be hereinafter understood to refer to the value determined on the same rubber as in the blend in the manner described. Still more preferred compositions meet both of the aforedescribed measures of state of cure, namely, by estimation of cross-link density and percent of rubber extractable.
A preferred composition of this invention comprises nylon as the thermoplastic engineering resin, and a brominated copolymer of isobutylene and a para-methylstyrene.

Thermoplastic blend containing engineering resin