The present invention relates to polycarbonate moulding compositions provided with phosphonate amines and phosphorus compounds, which moulding compositions exhibit excellent flame protection and very good mechanical properties, such as joint line strength or modulus of elasticity, and a good crude shade.

The present invention relates to polycarbonate-ABS blends provided with phosphonate amines and phosphorus compounds, which blends exhibit excellent flame protection and very good mechanical properties, such as joint line strength or modulus of elasticity, and a good crude shade.
U.S. Pat. No. 4,073,767 and 5,844,028 describe cyclic phosphorus compounds including phoshorinane rings as suitable flameproofing agents for polyurethanes, polycarbonates, polyesters and polyamides. In U.S. Pat. No. 4,397,750, particular cyclic phosphonate esters are described as efficient flameproofing agents for polypropylene and other polyolefins. U.S. Pat. No. 5,276,066 and U.S. Pat. No. 5,844,028 describe particular (1,3,2-dioxaphosphorinanemethane)-amines which are suitable flameproofing agents for polyurethanes, polyesters, styrene polymers, PVC, PVAc or polycarbonate.
U.S. Pat. No. 3,505,431, French-Patent 1 371 139, U.S. Pat. Nos. 3,711,577, 4,054,544 describe acyclic trisphosphonate amines, some of which are halogenated.
EP-A0 640 655 describes moulding compositions of aromatic polycarbonate, styrene-containing copolymers and graft polymers, which moulding compositions can be rendered flame-resistant with monomeric and/or oligomeric phosphorus compounds.
In EP-A 0 363 608, flame-resistant polymer mixtures of aromatic polycarbonate, styrene-containing copolymer or graft copolymer and oligomeric phosphates are described as flameproofing additives. For some applications, such as, for example, mouldings inside casing parts, the dimensional stability of those mixtures under heat is often inadequate.
In U.S. Pat. No. 5,061,745, polymer mixtures of aromatic polycarbonate, ABS graft polymer and/or styrene containing copolymer and monophosphates are described as flameproofing additives. The level of resistance of those mixtures to stress cracking is often inadequate for the production of thin-walled casing parts.
A combination of phosphonate amines and phosphorus compounds is not described either in WO 9740092 or in EP-A 728 811.
The object of the present invention is to provide polycarbonate moulding compositions having improved flame resistance as a result of improved after-burning times and excellent mechanical properties, such as joint line strength, modulus of elasticity, as well as good processability and a good crude shade. That spectrum of properties is required especially in the case of applications in the field of data technology, such as, for example, for casings for monitors, printers, copiers, etc.
It has now been found that compositions containing polycarbonate and phosphonate amines in combination with phosphorus compounds and/or salts of phosphate compounds and, optionally, other blend partners exhibit the desired properties.
Accordingly, the invention provides compositions containing polycarbonate, at least one phosphonate amine of formula (I)
A3xe2x88x92yxe2x80x94Nxe2x80x94Byxe2x80x83xe2x80x83(I),
in which
A represents a radical of formula (IIa)
R1 and R2are each independently of the other unsubstituted or substituted C1-C10-alkyl or unsubstituted or substituted C6-C10aryl,
R3 and R4are each independently of the other unsubstituted or substituted C1-C10-alkyl or unsubstituted or substituted C6-C10-aryl, or
R3 and R4together represent unsubstituted or substituted C3-C10-alkylene,
y represents the numerical values 0, 1 or 2, and
the substituents B are each independently hydrogen, optionally halogenated C2-C8-alkyl, unsubstituted or substituted C6C10-aryl,
and at least one phosphorus compound of formulae (IIa), (IIb), (IIc) and (IId)
wherein
R1, R2, R3 and R4 are each independently of the others optionally halogenated C1- to C8-alkyl, or C5- to C6-cycloalkyl, C6- to C20aryl or C7- to C12-aralkyl each optionally substituted by alkyl, preferably C1-C4-alkyl, and/or by halogen, preferably chlorine, bromine,
the substituents n are each independently of the others 0 or 1,
k represents from 0 to 30, and
X represents a mono- or poly-nuclear aromatic radical having from 6 to 30 carbon atoms,
wherein
R1 and R6 are each independently of the other optionally halogenated C1-C24-alkyl, or C5-C6-cycloalkyl, C6-C20-aryl or C7-C12-allyl each optionally substituted by halogen and/or by C1-C10-alkyl,
or
R5 and R6 in the case of formula (IId) form an alkyl chain, preferably having up to 6, especially 2 or 3, carbon atoms,
Me represents a metal selected from main group 1 to 3 and subsidiary groups VIII, 1B and 2B of the periodic system,
and q is determined by the valency of the metal ion,
and, optionally, impact strength modifiers.
The composition according to the invention contains preferably from 0.1 to 30 parts by weight, especially from 1 to 25 parts by weight, very especially from 2 to 20 parts by weight, of phosphonate amine and preferably from 0.5 to 20 parts by weight, especially from 1 to 18 parts by weight, more especially from 2 to 15 parts by weight, of phosphorus compound, the indicated amounts being based on the total mixture.
The compositions preferably contain graft polymer and, optionally, vinyl (co)polymer and/or polyalkylene terephthalate as the impact strength modifier.
The invention preferably provides blends containing
A) from 40 to 99 parts by weight, preferably from 60 to 98.5 parts by weight, of aromatic polycarbonate and/or polyester carbonate,
B) from 0.5 to 60 parts by weight, preferably from 1 to 40 parts by weight, especially from 2 to 25 parts by weight, of graft polymer of
B.1) from 5 to 95 wt. %, preferably from 30 to 80 wt. %, of one or more vinyl monomers on
B.2) from 95 to 5 wt %, preferably from 20 to 70 wt. %, of one or more graft bases having a glass transition temperature  less than 10xc2x0 C., preferably  less than 0xc2x0 C., especially  less than xe2x88x9220xc2x0 C.,
C) from 0 to 45 parts by weight, preferably from 0 to 30 parts by weight, especially from 2 to 25 parts by weight, of at least one thermoplastic polymer selected from the group of the vinyl (co)polymers and polyalkylene terephthalates,
D) from 0.1 to 30 parts by weight, preferably from 1 to 25 parts by weight, especially from 2 to 20 parts by weight, of phosphonate amine of formula (I) described above,
E) from 0.5 to 20 parts by weight, preferably from 1 to 18 parts by weight, especially from 2 to 15 parts by weight, selected from at least one phosphorus compound of formulae (IIa), (IIb), (IIc) and (IId) described above,
F) from 0 to 5 parts by weight, preferably from 0.1 to 3 parts by weight, especially from 0.1 to 1 part by weight, more especially from 0.1 to 0.5 part by weight, of fluorinated polyolefin,
the sum of the parts by weight of the components being 100.
Component
Aromatic polycarbonates and/or aromatic polyester carbonates which are suitable according to the invention as component A are known in the literature or can be prepared by processes which are known in the literature (for the preparation of aromatic polycarbonates see, for example, Schnell, xe2x80x9cChemistry and Physics of Polycarbonatesxe2x80x9d, Interscience Publishers, 1964 and DE-AS 1 495 626, DE-OS 2 232 877, DE-OS 2 703 376, DE-OS 2 714 544, DE-OS 3 000 610, DE-OS 3 832 396; for the preparation of aromatic polyester carbonates see, for example, DE-OS 3 077 934).
The preparation of aromatic polycarbonates is carried out, for example, by reacting diphenols with carbonic acid halides, preferably phosgene, and/or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the phase boundary process, optionally using chain terminators, for example monophenols, and optionally using branching agents having a functionality of three or more, for example triphenols or tetraphenols.
Diphenols for the preparation of aromatic polycarbonates and/or aromatic polyester carbonates are preferably those of formula (III)
wherein
A represents a single bond, C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylidene, xe2x80x94Oxe2x80x94, xe2x80x94SOxe2x80x94, xe2x80x94COxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SO2xe2x80x94, C6-C12-arylene, to which there may be condensed other aromatic rings optionally containing hetero atoms.
or a radical of formula (IV) or (V)
each of the substituents B represents C1-C12-alkyl, preferably methyl, halogen, preferably chlorine and/or bromine,
the substituents x are each independently of the other 0, 1 or 2,
p represents 1 or 0, and
R7 and R8 can be selected individually for each X1 and are each independently of the other hydrogen or C1-C6-alkyl, preferably hydrogen, methyl or ethyl,
X1 represents carbon, and
m represents an integer from 4 to 7, preferably 4 or 5, with the proviso that at at least one atom X1, R7 and R8 are simultaneously alkyl.
Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols, bis-(hydroxyphenyl)-C1-C5-alkanes, bis(hydroxyphenyl)-C5-C6-cycloalkanes, bis-(hydroxyphenyl) ethers, bis-(hydroxyphenyl) sulfoxides, bis-(hydroxyphenyl) ketones, bis-(hydroxyphenyl)-sulfones and xcex1,xcex1-bis(hydroxyphenyl)-diisopropylbenzenes and their derivatives chlorinated and/or brominated at the ring.
Especially preferred diphenols are 4,4xe2x80x2-dihydroxydiphenyl, bisphenol A, 2,4-bis-(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4xe2x80x2-dihydroxydiphenyl sulfide, 4,4xe2x80x2-dihydroxydiphenyl-sulfone and their di- and tetra-brominated or -chlorinated derivatives, such as, for example, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-chloro-4-hydroxyphenyl)-propane or 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.
Special preference is given to 2,2-bis-4-hydroxyphenyl)-propane (bisphenol A).
The diphenols may be used individually or in the form of any desired mixtures.
The diphenols are known in the literature or obtainable by processes known in the literature.
Suitable chain terminators for the preparation of thermoplastic aromatic polycarbonates are, for example, phenol, p-chlorophenol, p-tert.-butylphenol or 2,4,6-tribromophenol, as well as long-chained alkylphenols, such as 4-(1,3-tetramethylbutyl)-phenol according to DE-OS 2 842 005 or monoalkylphenols or dialkylphenols having a total of from 8 to 20 carbon atoms in the alkyl substituents, such as 3,5-di-tert.-butylphenol, p-isooctylphenol, p-tert.octylphenol, p-dodecylphenol and 2-(3,5-dimethylheptyl)-phenol and 4-(3,5-dimethylheptyl)-phenol. The amount of chain terminators to be used is generally from 0.5 mol % to 10 mol %, based on the molar sum of the diphenols used in a particular case.
The thermoplastic aromatic polycarbonates have mean weight-average molecular weights (Mw, measured, for example, by means of an ultracentrifuge or by scattered-light measurement) of from 10,000 to 200,000, preferably from 20,000 to 80,000.
The thermoplastic aromatic polycarbonates may be branched in a known manner, preferably by the incorporation of from 0.05 to 2.0 mol %, based on the sum of the diphenols used, of compounds having a functionality of three or more, for example compounds having three or more phenolic groups.
Both homopolycarbonates and copolycarbonates are suitable. For the preparation of copolycarbonates according to the invention as component A), from 1 to 25 wt. %, preferably from 2.5 to 25 wt. % (based on the total amount of diphenols to be used) of polydiorganosiloxanes having hydroxy-aryloxy terminal groups may also be used. Those compounds are known (see, for example, U.S. Pat. No. 3,419,634) or can be prepared by processes known in the literature. The preparation of copolycarbonates containing polydiorganosiloxanes is described, for example, in DE-OS 3 334 782.
In addition to the homopolycarbonates of bisphenol A, preferred polycarbonates are the copolycarbonates of bisphenol A containing up to 15 mol %, based on the molar sum of diphenols, of diphenols other than those mentioned as being preferred or especially preferred, especially 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.
Aromatic dicarboxylic acid dihalides for the preparation of aromatic polyester carbonates are preferably the diacid dichlorides of isophthalic acid, terephthalic acid, diphenyl ether 4,4xe2x80x2-dicarboxylic acid and naphthalene-2,6-dicarboxylic acid. Special preference is given to mixtures of the diacid dichlorides of isophthalic acid and terephthalic acid in a ratio of from 1:20 to 20:1.
In the preparation of polyester carbonates, a carbonic acid halide, preferably phosgene, is additionally used concomitantly as bifunctional acid derivative.
In addition to the monophenols already mentioned, there come into consideration as chain terminators for the preparation of the aromatic polyester carbonates also the chlorocarbonic acid esters of the mentioned monophenols and the acid chlorides of aromatic monocarboxylic acids, which may optionally be substituted by C1-C22-alkyl groups or by halogen atoms, as well as aliphatic C2-C22-monocarboxylic acid chlorides.
The amount of chain terminators is in each case from 0.1 to 10 mol %, based in the case of phenolic chain terminators on moles of diphenols and in the case of monocarboxylic acid chloride chain terminators on moles of dicarboxylic acid dichlorides.
The aromatic polyester carbonates may also contain aromatic hydroxycarboxylic acids incorporated therein.
The aromatic polyester carbonates may be either linear or branched in a known manner (see in that connection also DE-OS 2 940 024 and DE-OS 3 007 934).
There may be used as branching agents, for example, carboxylic acid chlorides having a functionality of three or more, such as trimesic acid trichloride, cyanuric acid trichloride, 3,3xe2x80x2-4,4xe2x80x2-benzophenone-tetracarboxylic acid tetrachloride, 1,4,5,8-naphthalenetetracarboxylic acid tetrachloride or pyromellitic acid tetrachloride, in amounts of from 0.01 to 1.0 mol % (based on dicarboxylic acid dichlorides used), or phenols having a functionality of three or more, such as phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene-2,4,4-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, tri-(4-hydroxyphenyl)-phenylmethane, 2,2-bis[4,4-bis(4-hydroxyphenyl)-cyclohexyl]-propane, 2,4-bis(4-hydroxyphenyl-isopropyl)-phenol, tetra-(4-hydroxyphenyl)-methane, 2,6-bis-(2-hydroxy-5-methyl-benzyl-4-methylphenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane, tetra-(4-[4-hydroxyphenyl-isopropyl]-phenoxy)-methane, 1,4-bis-[4,4xe2x80x2-dihydroxy-triphenyl)methyl)-benzene, in amounts of from 0.01 to 1.0 mol %, based on diphenols used. Phenolic branching agents can be used initially with the diphenols, acid chloride branching agents can be introduced together with the acid dichlorides.
The content of carbonate structural units in the thermoplastic aromatic polyester carbonates can vary as desired. The carbonate group content is preferably up to 100 mol %, especially up to 80 mol %, more especially up to 50 mol %, based on the sum of ester groups and carbonate groups. Both the esters and the carbonates contained in the aromatic polyester carbonates can be present in the polycondensation product in the form of blocks or in a randomly distributed manner.
The relative solution viscosity (xcex7rel) of the aromatic polycarbonates and polyester carbonates is in the range of from 1.18 to 1.4, preferably from 1.22 to 1.3 (measured on solutions of 0.5 g of polycarbonate or polyester carbonate in 100 ml of methylene chloride solution at 25xc2x0 C.).
The thermoplastic aromatic polycarbonates and polyester carbonates may be used alone or in any desired mixture with one another.
Component B
Component B consists of one or more graft polymers of
B.1 from 5 to 95 wt. %, preferably from 30 to 80 wt. %, of at least one vinyl monomer with
B.2 from 95 to 5 wt. %, preferably from 70 to 20 wt. %, of one or more graft bases having glass transition temperatures  less than 10xc2x0 C., preferably  less than 0xc2x0 C., especially  less than xe2x88x9220xc2x0 C.
The graft base B.2 generally has a mean particle size (d50 value) of from 0.05 to 5 xcexcm, preferably from 0.10 to 0.5 xcexcm, especially from 0.20 to 0.40 xcexcm.
Monomers B.1 are preferably mixtures of
B.1.1 from 50 to 99 parts by weight of vinyl aromatic compounds and/or vinyl aromatic compounds substituted at the ring (such as, for example, styrene, xcex1-methylstyrene, p-methylstyrene, p-chlorostyrene) and/or methacrylic acid (C1-C4)-alkyl esters (such as, for example, methyl methacrylate, ethyl methacrylate) and
B.1.2 from 1 to 50 parts by weight of vinyl cyanides (unsaturated nitrites such as acrylonitrile and methacrylonitrile) and/or (meth)acrylic acid (C1-C8)-alkyl esters (such as, for example, methyl methacrylate, n-butyl acrylate, tert.-butyl acrylate) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (for example maleic anhydride and N-phenyl maleimide).
Preferred monomers B.1.1 are selected from at least one of the monomers styrene, xcex1-methylstyrene and methyl methacrylate; preferred monomers B.1.2 are selected from at least one of the monomers acrylonitrile, maleic anhydride and methyl methacrylate.
Especially preferred monomers are B.1.1 styrene and B.1.2 acrylonitrile.
Suitable graft bases B.2 for the graft polymers B are, for example, diene rubbers, EP(D)M rubbers, that is to say those based on ethylene/propylene and optionally diene, acrylate, polyurethane, silicone, chloroprene and ethylene/vinyl acetate rubbers.
Preferred graft bases B.2 are diene rubbers (for example based on butadiene, isoprene, etc.) or mixtures of diene rubbers or copolymers of diene rubbers or mixtures thereof with other copolymerisable monomers (for example according to B.1.1 and B.1.2), with the proviso that the glass transition temperature of component B.2 is below  less than 10xc2x0 C., preferably  less than 0xc2x0 C., especially  less than xe2x88x9210xc2x0 C.
Special preference is given to pure polybutadiene rubber.
Especially preferred polymers B are, for example, ABS polymers (emulsion, mass and suspension ABS), as are described, for example, in DE-OS 2 035 390 (=U.S. Pat. No. 3,644,574) or in DE-OS 2 248 242 (=GB-B 1 409 275) or in Ullmanns Enzyklopadie der Technischen Chemie, Vol. 19 (1980), p. 280 et seq. The gel content of the graft base B.2 is at least 30 wt. %, preferably at least 40 wt. % (measured in toluene).
The graft copolymers B are prepared by free-radical polymerisation, for example by emulsion, suspension, solution or mass polymerisation, preferably by emulsion polymerisation.
Especially suitable graft rubbers are also ABS polymers prepared by redox initiation using an initiator system of organic hydroperoxide and ascorbic acid according to U.S. Pat. No. 4,937,285.
Since it is known that the graft monomers are not necessarily grafted on to the graft base completely in the graft reaction, graft polymers B are also to be understood according to the invention as being products that are obtained by (co)polymerisation of the graft monomers in the presence of the graft base and that are also obtained during working up.
Suitable acrylate rubbers according to B.2 for the polymers B are preferably polymers of acrylic acid alkyl esters, optionally with up to 40 wt. %, based on B.2, of other polymerisable, ethylenically unsaturated monomers. The preferred polymerisable acrylic acid esters include C1-C8-alkyl esters, for example methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; haloalkyl esters, preferably halo-C1-C8-alkyl esters, such as chloroethyl acrylate, as well as mixtures of those monomers.
For crosslinking, monomers having more than one polymerisable double bond can be copolymerised. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having from 3 to 8 carbon atoms and of unsaturated monohydric alcohols having from 3 to 12 carbon atoms, or of saturated polyols having from 2 to 4 OH groups and from 2 to 20 carbon atoms, such as, for example, ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds, such as, for example, trivinyl and triallyl cyanurate; polyfunctional vinyl compounds, such as di- and tri-vinylbenzenes; and also triallyl phosphate and diallyl phthalate.
Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds having at least three ethylenically unsaturated groups.
Especially preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, triacryloylhexahydro-s-triazine, triallyl benzenes. The amount of crosslinking monomers is preferably from 0.02 to 5 wt. %, especially from 0.05 to 2 wt. %, based on the graft base B.2.
In the case of cyclic crosslinking monomers having at least three ethylenically unsaturated groups, it is advantageous to limit the amount to less than 1 wt. % of the graft base B.2.
Preferred xe2x80x9cotherxe2x80x9d polymerisable, ethylenically unsaturated monomers which can optionally be used, in addition to the acrylic acid esters, for the preparation of the graft base B.2 are, for example, acrylonitrile, styrene, xcex1-methylstyrene, acrylamides, vinyl C1-C6-alkyl ethers, methyl methacrylate, butadiene. Preferred acrylate rubbers as graft base B.2 are emulsion polymers having a gel content of at least 60 wt. %.
Other suitable graft bases according to B.2 are silicone rubbers having graft-active sites, as are described in DE-OS 3 704 657, DE-OS 3 704 655, DE-OS 3 631 540 and DE-OS 3 631 539.
The gel content of the graft base B.2 is determined at 25xc2x0 C. in a suitable solvent (M. Hoffmann, H. Krxc3x6mer, R. Kuhn, Polymeranalytik I und II, Georg Thieme-Verlag, Stuttgart 1977).
The mean particle size d50 is the diameter above and below which in each case 50 wt. % of the particles lie. It can be determined by means of ultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid, Z. und Z. Polymere 250 (1972), 782-796).
Component C
Component C consists of one or more thermoplastic vinyl (co)polymers C.1 and/or polyalkylene terephthalates C.2.
Suitable as vinyl (co)polymers C.1 are polymers of at least one monomer from the group of the vinyl aromatic compounds, vinyl cyanides (unsaturated nitriles), (meth)acrylic acid (C1-C8)-alkyl esters, unsaturated carboxylic acids and derivatives (such as anhydrides and imides) of unsaturated carboxylic acids. Especially suitable are (co)polymers of
C.1.1 from 50 to 99 parts by weight, preferably from 60 to 80 parts by weight, of vinyl aromatic compounds and/or vinyl aromatic compounds substituted at the ring (such as, for example, styrene, xcex1-methylstyrene, p-methylstyrene, p-chlorostyrene) and/or methacrylic acid (C1-C8-alkyl esters (such as, for example, methyl methacrylate, ethyl methacrylate),
C.1.2 from 1 to 50 parts by weight, preferably from 20 to 40 parts by weight, of vinyl cyanides (unsaturated nitriles), such as acrylonitrile and methacrylonitrile, and/or (meth)acrylic acid (C1-C8-alkyl esters (such as, for example, methyl methacrylate, n-butyl acrylate, tert.-butyl acrylate) and/or unsaturated carboxylic acids (such as maleic acid) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (for example maleic anhydride and N-phenyl maleimide).
The (co)polymers C.1 are resin-like, thermoplastic and rubber-free.
Special preference is given to the copolymer of C.1.1 styrene and C.1.2 acrylonitrile.
The (co)polymers according to C.1 are known and can be prepared by free-radical polymerisation, especially by emulsion, suspension, solution or mass polymerisation. The (co)polymers preferably have molecular weights {overscore (M)}w (weight average, determined by light scattering or sedimentation) of from 15,000 to 200,000.
The polyalkylene terephthalates of component C.2 are reaction products of aromatic dicarboxylic acids or reactive derivatives thereof, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols, and mixtures of those reaction products.
Preferred polyalkylene terephthalates contain at least 80 wt. %, preferably at least 90 wt. %, based on the dicarboxylic acid component, of terephthalic acid radicals and at least 80 wt. %, preferably at least 90 mol %, based on the diol component, of ethylene glycol and/or 1,4-butanediol radicals.
The preferred polyalkylene terephthalates may contain, in addition to terephthalic acid radicals, up to 20 mol %, preferably up to 10 mol %, of radicals of other aromatic or cycloaliphatic dicarboxylic acids having from 8 to 14 carbon atoms or of aliphatic dicarboxylic acids having from 4 to 12 carbon atoms, such as, for example, radicals of phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4xe2x80x2-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexane-diacetic acid.
The preferred polyalkylene terephthalates may contain, in addition to ethylene glycol or 1,4-butanediol radicals, up to 20 mol %, preferably up to 10 mol %, of other aliphatic diols having from 3 to 12 carbon atoms or cycloaliphatic diols having from 6 to 21 carbon atoms, for example radicals of 1,3-propanediol, 2-ethyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 3-ethyl-2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5-hexanediol, 1,4-di-(xcex2-hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane, 2,2-bis-(4-xcex2-hydroxyethoxy-phenyl)-propane and 2,2-bis-(4-hydroxypropoxyphenyl)-propane (DE-OS 2 407 674, 2 407 776, 2 715 932).
The polyalkylene terephthalates can be branched by the incorporation of relatively, small amounts of tri- or tetra-hydric alcohols or tri- or tetra-basic carboxylic acids, for example according to DEOS 1 900 270 and U.S. Pat. No. 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane, trimethylolpropane and pentaerythritol.
Special preference is given to polyalkylene terephthalates which have been prepared solely from terephthalic acid and reactive derivatives thereof (for example dialkyl esters thereof) and ethylene glycol and/or 1,4-butanediol, and mixtures of those polyalkylene terephthalates.
Mixtures of polyalkylene terephthalates contain from 1 to 50 wt. %, preferably from 1 to 30 wt. %, of polyethylene terephthalate and from 50 to 99 wt. %, preferably from 70 to 99 wt. %, of polybutylene terephthalate.
The polyalkylene terephthalates which are preferably used generally have an intrinsic viscosity of from 0.4 to 1.5 dl/g, preferably from 0.5 to 1.2 dl/g, measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25xc2x0 C. using an Ubbelohde viscometer.
The polyalkylene terephthalates can be prepared by known methods (see, for example, Kunststoff-Handbuch, Volume VIII, p. 695 et seq., Carl-Hanser-Verlag, Munich 1973).
Component D
The moulding compositions according to the invention contain as flameproofing agent at least one phosphonate amine compound of formula (I)
A3xe2x88x92yxe2x80x94Nxe2x80x94Byxe2x80x83xe2x80x83(I),
in which
wherein
R1, R2, R3 and R4 and B and y are as defined above.
The substituents B, each independently, are preferably hydrogen; ethyl, n-propyl or isopropyl, each of which may be substituted by halogen; C6-C10-aryl, especially phenyl or naphthyl, which is unsubstituted or substituted by C1C4-alkyl and/or by halogen.
Alkyl in R1, R2, R3 and R4, each independently of the others, is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, pentyl or hexyl.
Substituted alkyl in R1, R2, R3 and R4, each independently of the others, is preferably C1-C10-alkyl substituted by halogen, especially mono- or di-substituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, pentyl or hexyl.
R3 and R4, together with the carbon atom to which they are bonded, preferably form cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl, especially cyclopentyl or cyclohexyl.
C6-C10-Aryl in R1, R2, R3 and R4, each independently of the others, is preferably phenyl, naphthyl or binaphthyl, especially o-phenyl, o-naphthyl, o-binaphthyl, each of which may be substituted (generally mono-, di- or tri-substituted) by halogen.
The following are mentioned by way of preferred examples: 5,5,5xe2x80x2,5xe2x80x2,5xe2x80x3,5xe2x80x3-hexamethyl-tris(1,3,2-dioxaphosphorinane-methane)amin-2,2xe2x80x2,2xe2x80x3-trioxide of formula (I-1)
(test product XPM 1000, Solutia Inc., St Louis, USA) 1,3,2-dioxaphosphorinane-2-methaneamine, N-butyl-N[(5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl)methyl]-5,5-dimethyl-, P,2-dioxide; 1,3,2-dioxaphosphorinane-2-methaneamine, N-[(5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl)methyl]-5,5-dimethyl-N-phenyl-, P,2-dioxide; 1,3,2-dioxaphosphorinane-2-methaneamine, N,N-dibutyl-5,5-dimethyl-, 2-oxide, 1,3,2-dioxaphosphorinane-2-methaneamine, N-((5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl)methyl]-N-ethyl-5,5-dimethyl-, P,2-dioxide, 1,3,2-dioxaphosphorinane-2-methaneamine, N-butyl-N-[(5,5-dichloromethyl-1,3,2-dioxaphosphorinan-2-yl)methyl]-5,5-di-chloromethyl-, P,2-dioxide, 1,3,2-dioxaphosphorinane-2-methaneamine, N-[(5,5-di-chloromethyl-1,3,2-dioxaphosphorinan-2-yl)methyl]-5,5-dichloromethyl-N-phenyl-, P,2-dioxide; 1,3,2-dioxaphosphorinane-2-methaneamine, N,N-di-(4-chlorobutyl)-5,5-dimethyl-2-oxide; 1,3,2-dioxaphosphorinane-2-methaneamine, N-[(5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl)-methane]-N-(2-chloroethyl)-5,5-di(chloromethyl), P,2-dioxide.
Also preferred are:
compounds of formula (I-2) or (I-3)
xe2x80x83wherein
R1, R2, R3 and R4 are as defined above.
Compounds of formulae (I-2), (I-1) are especially preferred. The individual compounds mentioned above are also especially preferred.
The compounds of formula (I) can be prepared by the following processes:
a) PCl3 is added to a mixture of 1,3-diol derivatives, water and an organic solvent at a temperature of from 10 to 60xc2x0 C., yielding a 5,5-disubstituted 1,3,2-dioxaphosphorinane 2-oxide of formula (Ia)
xe2x80x83wherein R1 and R2 are as defined above;
b) after purification, the 1,3,2-dioxaphosphorinane 2-oxide is reacted in paraformaldehyde with an amine ByNH3xe2x88x92y, wherein B and y are as defined above;
c) after further purification and drying, the phosphonate amine of formula (I) is obtained.
A detailed description of the preparation process can be found in U.S. Pat. No. 5,844.028.
Component E
Component E consists of one or more phosphorus compounds or a mixture of at least one monomeric and at least one oligomeric phosphorus compound of formulae (IIa), (IIb), (IIc) and (IId) mentioned above.
In formula (IIa), R1, R2, R3 and R4 are as defined above. Preferably, R1, R2, R3 and R4 are each independently of the others C1-C4-alkyl, phenyl, naphthyl or phenyl-C1-C4-alkyl. The aromatic groups R1, R2, R3 and R4 may in turn be substituted by halogen and/or alkyl groups, preferably chlorine, bromine and/or C1-C4-alkyl. Especially preferred aryl radicals are cresyl, phenyl, xylenyl, propylphenyl or butylphenyl and the corresponding brominated and chlorinated derivatives thereof.
X in formula (IIa) represents a mono- or poly-nuclear aromatic radical having from 6 to 30 carbon atoms. It is preferably derived from diphenols of formula (III), such as, for example, diphenylphenol, bisphenol A, or from resorcinol or hydroquinone or their chlorinated or brominated derivatives.
each of the substituents n in formula (IIa), independently of the others, may be 0 or 1; n is preferably 1.
k represents values from 0 to 30, preferably an average value of from 0.3 to 20, especially from 0.5 to 10, more especially from 0.5 to 6.
There are used as component E according to the invention especially mixtures of preferably from 10 to 90 wt. %, preferably from 12 to 40 wt. %, of at least one monophosphorus compound and at least one oligomeric phosphorus compound of formula (IIa) or of a mixture of oligomeric phosphorus compounds in amounts of from 10 to 90 wt. %, preferably from 60 to 88 wt. %, based on the total amount of phosphorus compounds.
Monophosphorus compounds of formula (IIa) are especially tributyl phosphate, tris-(2-chloroethyl) phosphate, tris-(2,3-dibromopropyl) phosphate, triphenyl phosphate, tricresyl phosphate, diphenylcresyl phosphate, diphenyloctyl phosphate, diphenyl-2-ethylcresyl phosphate, tri-(isopropylphenyl) phosphate, halo-substituted aryl phosphates, methylphosphonic acid dimethyl esters, methylphosphonic acid diphenyl esters, phenylphosphonic acid diethyl esters, triphenylphosphine oxide or tricresylphosphine oxide.
The mixtures of monomeric and oligomeric phosphorus compounds of formula (I) have average k values of from 0.3 to 20, preferably from 0.5 to 10, especially from 0.5 to 6.
The phosphorus compounds of component E are known (see, for example, EP-A 363 608, EP-A 640 655) or can be prepared according to known methods in an analogous manner (for example, Ullmanns Encyklopxc3xa4die der technischen Chemie, Vol. 18, p. 301 et seq. 1979; Houben-Weyl, Methoden der organischen Chemie, Vol. 12/1, p. 43; Beilstein Vol. 6, p. 177).
The moulding compositions according to the invention may contain as phosphorus compounds metal compounds of monoesters of phosphoric acid of formula (IIb) and/or (IIc)
or metal compounds of diesters phosphoric acid according to formula (IId)
wherein R5 and R6, Me and q are as defined above.
R5 and R6 are each independently of the other preferably optionally halogenated (preferably by chlorine and/or bromine) C1-C15-alkyl, especially C1-C10-alkyl, or cyclopentyl, cyclohexyl, phenyl, naphthyl or phenyl-C1-C4-alkyl (such as benzyl) each optionally substituted by halogen (preferably chlorine and/or bromine) and/or by C1-C6-alkyl, especially C1-C4-alkyl, especially methyl, ethyl, n-propyl or isopropyl.
R5 and R6 are each independently of the other especially cresyl, phenyl, xylenyl, propylphenyl or butylphenyl and the corresponding brominated and chlorinated derivatives thereof.
Suitable metals Me are main groups 1 to 3 and subsidiary groups VIII, IB and IIB of the periodic system (according to Mendeleyev), with metals from main groups 2 and 3 and from subsidiary group II being preferred.
Special preference is given to the compounds of the metals Mg, Ca, Ba, boron, Al and Zn.
Suitable processes for the preparation of the metal compounds according to the invention of phosphoric acid esters are processes known in the literature, such as, for example, the transesterification process starting from triesters of phosphoric acid, or the acid halide process starting from phosphoryl chloride (EP-A 0 801 116; J. Org. Chem. 1978, Vol. 43, No. 1, p. 24-31).
In the preparation of the phosphoric acid esters according to the invention, the inorganic reaction components are preferably used in very finely divided form. The average particle diameters are xe2x89xa61 xcexcm, preferably xe2x89xa6200 nm.
Component F
The fluorinated polyolefins F have a high molecular weight and have glass transition temperatures above xe2x88x9230xc2x0 C., generally above 100xc2x0 C., fluorine contents of preferably from 65 to 76 wt. %, especially from 70 to 76 wt. %, and mean particle diameters d50 of from 0.05 to 1000 xcexcm, preferably from 0.08 to 20 xcexcm. In general, the fluorinated polyolefins F have a density of from 1.2 to 2.3 g/cm3. Preferred fluorinated polyolefins F are polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene/hexafluoropropylene and ethylene/tetrafluoroethylene copolymers. The fluorinated polyolefins are known (see xe2x80x9cVinyl and Related Polymersxe2x80x9d by Schildknecht, John Wiley and Sons, Inc., New York, 1962, pages 484-494; xe2x80x9cFluorpolymersxe2x80x9d by Wall, Wiley-Interscience, John Wiley and Sons, Inc., New York, Volume 13, 1970, pages 623-654; xe2x80x9cModern Plastics Encyclopediaxe2x80x9d, 1970-1971, Volume 47, No. 10 A, October 1970, McGraw-Hill, Inc., New York, pages 134 and 774; xe2x80x9cModern Plastics Encyclopediaxe2x80x9d, 1975-1976, October 1975, Volume 52, No. 10 A, McGraw-Hill, Inc., New York, pages 27, 28 and 472; and U.S. Pat. No. 3,671,487, 3,723,373 and 3,838,092).
They can be prepared by known processes, for example by polymerisation of tetrafluoroethylene in an aqueous medium with a catalyst that forms free radicals, for example sodium, potassium or ammonium peroxodisulfate, at pressures of from 7 to 71 kg/cm2 and at temperatures of from 0 to 200xc2x0 C., preferably at temperatures of from 20 to 100xc2x0 C. (For further details see, for example, U.S. Pat. No. 2,393,967.) Depending on the form in which they are used, the density of those materials may be from 1.2 to 2.3 g/cm3 and the mean particle size may be from 0.5 to 1000 xcexcm.
Preferred fluorinated polyolefins F according to the invention are tetrafluoroethylene polymers having a mean particle diameter of from 0.05 to 20 xcexcm, preferably from 0.08 to 10 xcexcm, and a density of from 1.2 to 1.9 g/cm3 and are preferably used in the form of a coagulated mixture of emulsions of the tetrafluoroethylene polymers F with emulsions of the graft polymers B.
Other preparations which are preferred according to the invention are the fluorinated polyolefins F:
F.1) in the form of a coagulated mixture with at least one of components A to C, the fluorinated polyolefin F or polyolefin mixture being mixed in the form of an emulsion with at least one emulsion of components A to C and subsequently being coagulated;
F.2) in the form of a pre-compound with at least one of components A to C, the fluorinated polyolefins F being mixed in the form of a powder with a powder or a granulate of at least one of components A to C and being compounded in the melt, generally at temperatures of from 208xc2x0 C. to 330xc2x0 C., in conventional devices such as kneaders, extruders or double-shaft screws.
Preferred preparations for the fluorinated polyolefins F are coagulated mixtures with a graft polymer B or a vinyl (co)polymer C.
Suitable fluorinated polyolefins F which can be used in powder form are tetrafluoroethylene polymers having a mean particle diameter of from 100 to 1000 xcexcm and densities of from 2.0 g/cm3 to 2.3 g/cm3.
For the preparation of a coagulated mixture of B and F, an aqueous emulsion (latex) of a graft polymer B is first mixed with a finely divided emulsion of a tetrafluoroethylene polymer F; suitable tetrafluoroethylene polymer emulsions usually have solids contents of from 30 to 70 wt. %, especially from 50 to 60 wt. %, preferably from 30 to 35 wt. %.
The amount indicated in the description of component B can include the amount of graft polymer for the coagulated mixture of graft polymer and fluorinated polyolefin.
In the emulsion mixture, the equilibrium ratio of graft polymer B to tetrafluoroethylene polymer F is from 95:5 to 60:40. The emulsion mixture is subsequently coagulated in a known manner, for example by spray drying, lyophilisation or coagulation by the addition of inorganic or organic salts, acids, bases or organic, water-miscible solvents, such as alcohols, ketones, preferably at temperatures of from 20 to 150xc2x0 C., especially from 50 to 100xc2x0 C. If necessary, drying can be carried out at from 50 to 200xc2x0 C., preferably from 70 to 100xc2x0 C.
Suitable tetrafluoroethylene polymer emulsions are commercially available products and are sold, for example, by DuPont as Teflon(copyright) 30 N.
The moulding compositions according to the invention may contain at least one of the conventional additives, such as lubricating and mould-release agents, nucleating agents, antistatics, stabilisers as well as colourings and pigments.
The moulding compositions according to the invention may contain up to 35 wt %, based on the total moulding composition, of a further flameproofing agent optionally having a synergistic action. There are mentioned as examples of further flameproofing agents organic halogen compounds, such as decabromobisphenyl ether, tetrabromobisphenol, inorganic halogen compounds, such as ammonium bromide, nitrogen compounds, such as melamine, melamine-formaldehyde resins, inorganic hydroxide compounds, such as magnesium and aluminium hydroxide, inorganic compounds, such as antimony oxides, hydroxoantimonate, zirconium, oxide, zirconium hydroxide, molybdenum oxide, ammonium molybdate, zinc borate, ammonium borate, barium metsborate, talc, silicate, silicon dioxide and tin oxide as well as siloxane compounds.
The blends according to the invention containing components A to F and, optionally, other known additives, such as stabilisers, colourings, pigments, lubricating and mould-release agents, nucleating agents and antistatics, are prepared by mixing the constituents in question in a known manner and melt compounding and melt-extruding the mixture at temperatures of from 200xc2x0 C. to 300xc2x0 C. in conventional devices such as kneaders, extruders and double-shaft screws, component F preferably being used in the form of the coagulated mixture mentioned above.
The individual constituents may be mixed in a known manner either in succession or simultaneously, either at approximately 20xc2x0 C. (room temperature) or at a higher temperature.
Accordingly, the invention also provides a process for producing the moulding compositions.
On account of their excellent flame resistance and joint line strength and their good mechanical properties, the blends according to the invention are suitable for the production of moulded bodies of any kind, especially those having increased requirements as regards fracture resistance.
The blends of the present invention can be used in the production of moulded bodies of any kind. In particular, moulded bodies can be produced by injection moulding. Examples of moulded bodies which can be produced are: casing parts of any kind, for example for domestic appliances such as juice extractors, coffee machines, mixers, for office equipment such as monitors, printers, copiers, or covering plates for the construction sector and parts for the motor vehicle sector. They can also be used in the field of electrical engineering because they have very good electrical properties.
The moulding compositions according to the invention can also be used, for example, for producing the following moulded bodies or mouldings:
parts for finishing the interior of track vehicles, hub caps, casings for electrical appliances containing small transformers, casings for devices for distributing and transmitting information, casings and coverings for medical purposes, massage devices and casings therefor, toy vehicles for children, flat prefabricated wall panels, casings for security devices, rear spoilers, heat-insulated transport containers, device for keeping or caring for small animals, mouldings for sanitary and bathroom fittings, grids for covering ventilation openings, mouldings for garden and tool sheds, casings for gardening tools.
Another form of processing is the production of moulded bodies by deep-drawing from previously prepared sheets or films.
Accordingly, the present invention relates also to the use of the moulding compositions according to the invention in the production of moulded bodies of any kind, preferably of those mentioned above, and to the moulded bodies produced from the moulding compositions according to the invention.

Flame-resistant polycarbonate ABS moulding materials


Cationic azo dyes of the general formula I

The present invention relates to cationic azo dyes of the general formula I
where
R1 and R2 are independently hydrogen, nitro, halogen, C1-C6-alkyl,
R3 is hydrogen, C1-C6-alkyl with or without interruption by 1 or 2 nonadjacent oxy, imino, C1-C6-alkylimino groups or by a
xe2x80x83radical,
A1 and A2 are independently oxy, imino or substituted or unsubstituted C1-C6-alkylimino,
B1 and B2 are independently C1-C6-alkylene with or without interruption by 1 or 2 nonadjacent oxy, imino, substituted or unsubstituted C1-C6-alkylimino groups or by a
xe2x80x83radical,
Anxe2x8ax96is the equivalent of an anion,
n is 1, and
K is the radical of a coupling component or the radical of a monoazo dye of the formula
xe2x80x83where
R4xe2x80x2 and R5xe2x80x2 are independently hydroxyl, amino, morpholino or mono- or di(C1-C6)alkylamino, whose alkyl radicals are unsubstituted or substituted by hydroxyl, amino, cyano, C1-C6-alkoxycarbonyl, carbamoyl or mono- or di(C1-C6)alkylcarbamoyl and uninterrupted or interrupted by oxy, and
Q1, Q2 and Q3 are independently hydrogen, C1-C10-alkyl with or without interruption by from 1 to 4 nonadjacent oxy, imino and substituted or unsubstituted C1-C4-alkylimino groups and with or without hydroxyl, halogen or phenyl substitution, or Q1 and Q2 combine with the linking nitrogen atom to form a 5- or 6-membered heterocyclic radical which optionally contains nitrogen or oxygen as further hetero atom,
and additionally n is from 2 to 8 when K is the radical of a coupling component of the formula IIIaxe2x80x2
xe2x80x83where
R6xe2x80x2, is hydrogen, C1-C6-alkoxy with or without oxy interruption in its alkyl radical, mono- or di(C1-C6)alkylamino, C1-C6-alkoxycarbonyl, carbamoyl, mono- or di(C1-C6)alkylcarbamoyl, sulfamoyl, mono- or di(C1-C6)alkylsulfamoyl,
processes for their preparation, their use for dyeing and printing natural or synthetic substrates and also their mixtures.
DE-A-2 218 645 describes water-insoluble trisazo pigments which are monoazo dyes linked via triethanolamine.
DE-A-2 160 590 describes anthranilic acid derivatives bridged with a diethanolamine via the ester group. These diamines are useful for preparing polyurethanes.
It is an object of the present invention to provide novel dyes which have advantageous application properties, especially high affinities for the substrates used, and also good fastness to bleeding and lightfastness.
We have found that this object is achieved by the dyes of the formula I which are defined at the beginning.
Alkyl and alkylene appearing in the abovementioned formula may be straight-chain or branched.
Substituted alkyl appearing in the abovementioned formula may have as substituents for example hydroxyl and methoxy. The number of substituents in the substituted alkyl is generally 1 or 2.
Q1 and Q2 combining with the joining nitrogen atom to form a 5- or 6-membered heterocyclic radical which optionally contains nitrogen or oxygen as further hetero atom may be saturated radicals such as pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl with or without methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, 2-hydroxyethyl or 2- or 3-hydroxypropyl substitution on the nitrogen. Further possibilities are unsaturated radicals such as pyrrolyl, pyrazolyl, oxazolyl, isooxazolyl or imidazolyl with or without methyl, ethyl, propyl or butyl substitution in 2- and/or 4-position or N-3(C1-C4)alkylimidazolyl with or without methyl, ethyl, propyl or butyl substitution in 2- and/or 4-position.
Halogen is fluorine, chlorine or bromine.
R1, R2, R3, Q1, Q2 and Q3 are each for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl or 2-methylpentyl.
R3, Q1, Q2 and Q3 may each also be for example 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 4-methoxybutyl, 2- or 4-ethoxybutyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl, 3,7-dioxaoctyl, 4,7-dioxaoctyl, N,N-dimethylaminoethyl, N,N-diethylaminoethyl, 3-(N,N-dimethylamino)propyl, 3-(N,N-diethylamino)propyl, 2-methylaminoethyl, 2-ethylaminoethyl, 3-propylaminoethyl, 2- or 3-methylaminopropyl, 2- or 3-ethylaminopropyl or 2- or 3-propylaminopropyl.
Q1, Q2 and Q3 may each also be for example heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl (the above designations isooctyl, isononyl and isodecyl are trivial names derived from the alcohols obtained by the oxo process - cf. Ullmanns Encyklopxc3xa4die der technischen Chemie, 4th edition, volume 7, pages 215 to 217, and also volume 11, pages 435 and 436), 2-hydroxyethyl, 2- or 3-hydroxypropyl, 2- or 4-hydroxybutyl, 2-chloroethyl, 2- or 3-chloropropyl, 2- or 4-chlorobutyl, benzyl, 1- or 2-phenylethyl, 2- or 3-butoxypropyl, 2- or 4-propoxybutyl, 4,8-dioxadecyl, 3,7-dioxanonyl, 4,7-dioxanonyl, 2- or 4-butoxybutyl, 3,6,9-trioxadecyl, 3,6,9-trioxaundecyl, 3,6,9-trioxadodecyl, 3,6,9,12-tetraoxatridecyl, 3,6,9,12-tetraoxatetradecyl, 4-hydroxy-2-methyl-3-azabutyl, 4-hydroxy-3-hydroxymethyl-2-methyl-3-azabutyl, 5-hydroxy-2-methyl-3-azapentyl, 5-hydroxy-3-(2-hydroxy-ethyl)-2-methyl-3-azapentyl, 8-hydroxy-2-methyl-3-aza-6-oxaoctyl, 11-hydroxy-2-methyl-3-aza-6,9-dioxaundecyl, 8-hydroxy-(5-hydroxy-3-oxapentyl)-2-methyl-3-aza-6-oxaoctyl or 11-hydroxy-3-(8-hydroxy-3,6-dioxaoctyl)-2-methyl-3-aza-6,9-dioxaundecyl, N,N-dipropylaminoethyl, N,N-dibutylaminoethyl,3-(N,N-dipropylamino)propyl or 3-(N,N-dibutylamino)propyl.
A is for example methylimino, ethylimino, propylimino, isopropylimino, butylimino, isobutylimino, sec-butylimino, tert-butylimino, pentylimino, isopentylimino, neopentylimino, tert-pentylimino, hexylimino or 2-methylpentylimino.
B1 and B2 are each for example methylene, ethylene, 1,2- or 1,3-propylene, 1,2-, 2,3- or 1,4-butylene, (CH2)2O(CH2)2, (CH2)3O(CH2)2, (CH2)3O(CH2)3, (CH2)2O(CH2)2O(CH2)2, (CH2)2NH(CH2)2, (CH2)3NH(CH2)2, (CH2)2NH(CH2)2NH(CH2)2,
Anxe2x8ax96, the equivalent of an anion, is derived for example from the following anions: fluoride, chloride, bromide, iodide, sulfate, phosphate, formate, acetate, propionate, mono-, di- or trichloroacetate, lactate, methoxyacetate, citrate, succinate, methanesulfonate, benzenesulfonate, 2- or 4-methylbenzenesulfonate or naphthalenesulfonate.
Suitable coupling components KH are compounds of the benzene, naphthalene, quinolene, pyridone, barbituric acid or pyrazolone series and correspond for example to the compounds of the formulae III a-f
where
R4 is hydroxyl, amino, morpholino, mono- or di(C1-C6)alkylamino whose alkyl radicals are unsubstituted or substituted by hydroxyl, amino, cyano, C1-C6-alkoxycarbonyl, carbamoyl or mono or di(C1-C6)alkylcarbamoyl and are uninterrupted or interrupted by oxy or is C1-C6-alkoxy,
R5 is hydrogen, C1-C6-alkyl or R4,
R6 is hydrogen, C1-C6-alkyl, C1-C6-alkoxy with or without oxy interruption in its alkyl radical, mono or di(C1-C6)alkylamino, C1-C6-alkoxycarbonyl, carbamoyl, mono or di(C1-C6)alkylcarbamoyl whose alkyl radicals are unsubstituted or substituted by hydroxyl or amino and are uninterrupted or oxy interrupted, sulfamoyl, mono or di(C1-C6)alkylsulfamoyl whose alkyl radicals are unsubstituted or hydroxyl or amino substituted and uninterrupted or oxy interrupted, or is carboxyl,
R7 is hydroxyl, amino, mono or di(C1-C12)alkylamino, cyclohexylamino,
R8 is hydrogen, hydroxyl, amino, formylamino, acetylamino, C1-C6-alkyl,
R9 is hydrogen, C1-C6-alkyl, phenyl, hydroxyl, cyano, acetyl, benzoyl, methoxycarbonyl, carbamoyl,
R10 is hydrogen, chlorine, bromine, acetylamino, amino, nitro, sulfamoyl, methylsulfonyl, phenylsulfonyl, C1-C4-alkoxycarbonyl, C1-C4-alkanoyl, benzoyl, carbamoyl, cyano, N-methylimidazolyl, pyridinio,
R11 is hydrogen, C1-C6-alkyl with or without phenyl, hydroxyl, amino, C1-C6-alkoxy, acetylamino, benzoylamino or cyano substitution, cyclohexyl, phenyl with or without benzoylamino, acetylamino, methyl, methoxy, cyano or chlorine substitution, or amino which is substituted by phenyl, C1-C6-alkyl, C1-C6-alkanoyl or benzoyl,
R12 or R13 are independently hydrogen or C1-C6-alkyl,
R14 is methyl, C1-C4-alkoxycarbonyl or phenyl,
R15 is hydrogen, C1-C6-alkyl, cyclohexyl, benzyl or phenyl which is unsubstituted or from singly to triply substituted by fluorine, chlorine, bromine, C1-C4-alkyl, C1-C4-alkoxy, cyano, acetyl, acetylamino, hydroxyl, sulfamoyl or carbamoyl.
R4, R6 and R7 are each for example mono- or dimethylamino, mono- or diethylamino, mono- or dipropylamino, mono- or diisopropylamino, mono- or dibutylamino, mono- or dipentylamino, mono- or diisopentylamino, mono- or dineopentylamino, mono- or dihexylamino, mono- or di-2-methylpentylamino, N-methyl-n-butylamino, N-ethyl-n-butylamino.
R4 may also be for example mono- or di(2-hydroxyethyl)amino, mono-or di(2-hydroxypropyl)amino, mono- or di(3-hydroxypropyl)amino, N-methyl-2-hydroxyethylamino, N-methyl-2-hydroxypropylamino, N-methyl-3-hydroxypropylamino, N-ethyl-2-hydroxyethylamino, N-ethyl-2-hydroxypropylamino, N-ethyl-3-hydroxypropylamino, N-propyl-2-hydroxyethylamino, N-propyl-2-hydroxypropylamino, N-propyl-3-hydroxypropylamino, N-isopropyl-2-hydroxyethylamino, -2-hydroxypropylamino, -3-hydroxypropylamino, mono- or di(2-aminoethyl)amino, mono- or di(2-aminopropyl)amino, mono- or di(3-aminopropyl)amino, mono- or di(2-aminobutyl)amino, mono- or di(4-aminobutyl)amino, 2-cyanoethylamino, 2-cyano-2-methylethylamino, 2-methoxycarbonylethylamino, 2-methoxycarbonyl-2-methylethylamino, 2-ethoxycarbonylethylamino, 2-ethoxycarbonyl-2-methylethylamino, 2-propoxycarbonylethylamino, 2-propoxycarbonyl-2-methylethylamino, 2-isopropoxycarbonylethylamino, 2-isopropoxycarbonyl-2-methylethylamino, 2-butoxycarbonylethylamino, 2-butoxycarbonyl-2-methylethylamino, 2-carbamoylethylamino, 2-carbamoyl-2-methylethylamino, 2-mono or dimethylaminocarbonylethylamino, 2-mono or dimethylaminocarbonyl-2-methylethylamino, mono or di(2-methoxyethyl)amino, mono or di(2-methoxypropyl)amino, mono-or di(3-methoxypropyl)amino, or mono or di(2-hydroxyethyloxyethyl)amino.
R5, R6, R8, R9, R11, R12, R13 and R15 are each for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl or 2-methylpentyl.
R11 is hydroxy-C1-C4-alkyl such as hydroxymethyl, 1-hydroxyeth-1-yl, 2-hydroxyeth-1-yl, 1-hydroxy-prop-1-yl, 2-hydroxyprop-1-yl, 3-hydroxyprop-1-yl, 1-hydroxy-prop-2-yl, 2-hydroxyprop-2-yl, 1-hydroxybut-1-yl, 2-hydroxybut-1-yl, 3-hydroxybut-1-yl, 4-hydroxybut-1-yl, 1-hydroxybut-2-yl, 2-hydroxybut-2-yl, 1-hydroxybut-3-yl, 2-hydroxybut-3-yl, 1-hydroxy-2-methyl-prop-3-yl, 2-hydroxy-2-methyl-prop-3-yl, 3-hydroxy-2-methyl-prop-3-yl, 2-hydroxymethyl-prop-2-yl, cyanomethyl, cyanoethyl, cyanopropyl or cyanobutyl.
R11 may also be for example benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylprop-1-yl, 2-phenylprop-1-yl, 3-phenylprop-1-yl, 1-phenylbut-1-yl, 2-phenylbut-1-yl, 3-phenylbut-1-yl, 4-phenylbut-1-yl, 1-phenylbut-2-yl, 2-phenylbut-2-yl, 3-phenylbut-2-yl, 4-phenylbut-2-yl, 1-(phenylmethyl)-eth-1-yl, 1-(phenylmethyl)-1-(methyl)-eth-1-yl, 1-(phenylmethyl)-prop-1-yl, preferably benzyl and 2-phenylethyl, methoxymethyl, ethoxymethyl, n-propoxymethyl, (1-methylethoxy)methyl, n-butoxymethyl, (1-methylpropoxy)methyl, (2-methylpropoxy)methyl, (1,1-dimethylethoxy)methyl, 2-(methoxy)ethyl, 2-(ethoxy)ethyl, 2-(n-propoxy)ethyl, 2-(1-methoxyethoxy)ethyl, 2-(n-butoxy)ethyl, 2-(1-methylpropoxy)ethyl, 2-(2-methylpropoxy)ethyl, 2-(1,1-dimethylethoxy)ethyl, 2-(methoxy)propyl, 2-(ethoxy)propyl, 2-(n-propoxy)propyl, 2-(1-methylethoxy)propyl, 2-(n-butoxy)propyl, 2-(1-methylpropoxy)propyl, 2-(2-methylpropoxy)propyl, 2-(1,1-dimethylethoxy)propyl, 3-(methoxy)propyl, 3-(ethoxy)propyl, 3-(n-propoxy)propyl, 3-(1-methylethoxy)propyl, 3-(n-butoxy)propyl, 3-(1-methylpropoxy)propyl, 3-(2-methylpropoxy)propyl, 3-(1,1-dimethylethoxy)propyl, 2-(methoxy)butyl, 2-(ethoxy)butyl, 2-(n-propoxy)butyl, 2-(1-methylethoxy)butyl, 2-(n-butoxy)butyl, 2-(1-methylpropoxy)butyl, 2-(2-methylpropoxy)butyl, 2-(1,1-dimethylethoxy)butyl, 3-(methoxy)butyl, 3-(ethoxy)butyl, 3-(n-propoxy)butyl, 3-(1-methylethoxy)butyl, 3-(n-butoxy)butyl, 3-(1-methylpropoxy)butyl, 3-(2-methylpropoxy)butyl, 3-(1,1-dimethylethoxy)butyl, 4-(methoxy)butyl, 4-(ethoxy)butyl, 4-(n-propoxy)butyl, 4-(1-methylethoxy)butyl, 4-(n-butoxy)butyl, 4-(1-methylpropoxy)butyl, 4-(2-methylpropoxy)butyl or 4-(1,1-dimethylethoxy)butyl.
R10 is for example formyl, acetyl, propionyl, butyryl or isobutyryl.
R6 is for example mono- or dimethylcarbamoyl, mono- or diethylcarbamoyl, mono- or dipropylcarbamoyl, mono- or dibutylcarbamoyl, mono- or dipentylcarbamoyl or mono- or dihexylcarbamoyl.
R4 and R6 may each be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, isobutoxy or tert-butoxy.
R6 may also be for example methoxyethyloxy, methoxypropyloxy, ethoxyethyloxy, ethoxypropyloxy or propoxypropyloxy.
R15 is for example 2-, 3- or 4-fluorophenyl, 2-, 3- or 4-chlorophenyl, 2-, 3- or 4-bromophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-ethylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-cyanophenyl, 2-, 3- or 4-hydroxyphenyl, 2-, 3- or 4-acetylphenyl, 2-, 3- or 4-acetylaminophenyl, 2-, 3- or 4-sulfamoylphenyl or 2-, 3- or 4-carbamoylphenyl.
R6, R10 and R14 may each also be for example methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentoxycarbonyl, isopentoxycarbonyl, neopentoxycarbonyl, tert-pentyloxycarbonyl, hexyloxycarbonyl or 2-methylpentyloxycarbonyl.
R6 may also be for example mono- or dimethylsulfamoyl, mono- or diethylsulfamoyl, mono- or dipropylsulfamoyl, mono- or dibutylsulfamoyl.
R11may also be for example aminomethyl, 2-aminoethyl, 2- or 3-aminopropyl, 2- or 4-aminobutyl, acetylaminomethyl, 2-acetylaminoethyl, 2- or 3-acetylaminopropyl, 2- or 4-acetylaminobutyl, benzoylaminomethyl, 2-benzoylaminoethyl, 2- or 3-benzoylaminopropyl, 2- or 4-benzoylaminobutyl, 2-, 3- or 4-benzoylaminophenyl, 2-, 3- or 4-acetylaminophenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-cyanophenyl, 2-, 3- or 4-chlorophenyl, phenylamino, methylamino, ethylamino, propylamino, isopropylamino, butylamino, isobutylamino, sec-butylamino, tert-butylamino, acetylamino, propionylamino, butyrylamino, isobutyrylamino, isobutyrylamino, valerylamino, isovalerylamino, pivaloylamino, pentylcarbonylamino or benzoylamino.
In what follows, coupling components KH are recited by way of example. Examples of coupling components of the benzene series are resorcinol, 2- and 4-methylresorcinol, 1,3-phenylenediamine, 3-aminophenol, 4-methyl-3-aminophenol, 5-amino-2-methylphenol, 4-ethyl-3-aminophenol, 3-N,N-diethylaminophenol, 2,4-diaminotoluene, 2,4-dihydroxybenzoic acid, 4-methyl-2-aminophenol, 3-acetaminophenol, 3-amino-4-hydroxybenzenesulfonamide, o-, m- or p-toluidine, o-, m- or p-xylidine, 2,5-dimethoxyaniline, 2-methoxy-5-methylaniline, 3-amino-4-methylacetanilide, 2- or 4-methoxyacetanilide, N-methylaniline, N-methyl-m-toluidine, N-ethylaniline, N,N-diethylaniline, E-ethyl-m-toluidine, N- ( 2-hydroxyethyl) aniline, N,N-dihydroxyethylaniline or N-(2-hydroxyethyl)-m-toluidine.
Coupling components of the naphthalene series are for example 1-naphthylamine, N-phenyl-1-naphthylamine, N-ethyl-1-naphthylamine, N-ethyl-2-naphthylamine, N-phenyl-2-naphthylamine, 1-naphthol, 2-naphthol, 2,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-hydroxynaphthalene-1-carboxylic acid, 2-hydroxynaphthalene-3-carboxylic acid, methyl 2-hydroxynaphthalene-3-carboxylate or 2-hydroxynaphthalene-3-carboxamide.
Coupling components of the quinoline series are for example 8-hydroxyquinoline, 8-hydroxy-2-methylquinoline, 8-aminoquinoline, 8-amino-2-methylquinoline, 2-hydroxyquinoline and 2,4-dihydroxyquinoline.
Pyridone coupling components are for example 1-ethyl-2-hydroxy-4-methyl-5-carbamoylpyrid-6-one, 1-(2xe2x80x2-hydroxyethyl)2-hydroxy-4-methyl-5-carbamoylpyrid-6-one, 1-phenyl-2-hydroxy-4-methyl-5-carbamoylpyrid-6-one, 1-ethyl-2-hydroxy-4-methyl-5-cyanopyrid-6-one, 1-methyl-2-hydroxy-4-methyl-5-cyanopyrid-6-one, 1-methyl-2-hydroxy-5-acetylpyrid-6-one, 1,4-dimethyl-2-hydroxy-5-cyanopyrid-6-one, 1,4-dimethyl-5-carbamoylpyrid-6-one, 2,6-dihydroxy-4-ethyl-5-cyanopyridine, 2-hydroxy-4-ethyl-5-carbamoylpyrid-6-one or 1-methyl-2-hydroxy-4-methylsulfonylpyrid-6-one.
Examples of suitable coupling components of the barbituric acid series are barbituric acid, dimethylbarbituric acid and diethylbarbituric acid.
Suitable pyrazolone coupling components are for example 3-methyl-or 3-(C1-C4-alkoxycarbonyl)pyrazol-5-ones which, in 1-position, may bear hydrogen, unsubstituted or methyl-, ethyl-, fluorine-, chlorine-, bromine-, methoxy-, ethoxy-, cyano-, acetylamino-, hydroxyl-, carbamoyl- or sulfamoyl-substituted phenyl. Examples are 1-(2xe2x80x2,5xe2x80x2-dichlorophenyl)-3-methylpyrazol-5-one, ethyl 1-phenylpyrazol-5-one-3-carboxylate and ethyl pyrazol-5-one-3-carboxylate.
Preference is given to dyes of the general formula I where R1 and R2 are each hydrogen.
Preference is further given to dyes where A1 and A2 on the one hand and B1 and B2 on the other are each the same radical.
B1 and B2 are each preferably C2-C6-alkylene with or without interruption by oxy or by C1-C6-alkylimino. B1 and B2 are preferably identical.
Coupling components KH are preferably compounds of the formulae IIIa and IIIb. Preference is given in particular to dyes of the general formula IV
where n is from 1 to 8 and R1, R2, R3, R4, R5, R6, A1, A2, B1, B2 and Anxe2x8ax96are each as defined above. Particular preference is given to coupling components of the formula IIIa where R4 is hydroxyl, amino, mono- or dimethyl- or -ethylamino or mono- or dihydroxyethylamino and R5 and R6 are independently hydrogen, hydroxyl, amino or methyl.
Particular preference is likewise given to coupling components of the formula IIIb where R7 is hydroxyl or amino.
Particular preference is given to the following coupling components: resorcinol, 3-aminophenol, m-phenylenediamine, xcex1- and xcex2-naphthol, m-toluidine and 2,5-dimethylaniline.
Preference is further given to dyes of the formula I where n is 1.
To prepare the dyes of the formula I, an amine of the formula V
where R1, R2, R3, A1, A2, B1 and B2 are each as defined above, can be conventionally diazotized and coupled with a coupling component KH. The pH is preferably within the range from 2 to 8.
Advantageously, the diazonium salt solution is metered into the solution of the coupling component. It is generally possible to use a single coupling component and also mixtures of a plurality of coupling components, for example so as to shade the hue.
By using coupling components capable of coupling twice it is possible to use the azo coupling reaction to obtain higher molecular weight dyes. These oligomeric dyes are obtainable by azo coupling of 1 mol equivalent of diamine of the formula IV onto from 1 to 2, preferably onto from 1 to 1.5, especially from 1 to 1.2, mol equivalents of a coupling component of the formula IIIaxe2x80x2
where
R4xe2x80x2 and R5xe2x80x2 are independently hydroxyl, amino, morpholino or mono-or di(C1-C6)alkylamino, whose alkyl radicals are unsubstituted or substituted by hydroxyl, amino, cyano, C1-C6-alkoxycarbonyl, carbamoyl or mono- or di(C1-C6)alkylcarbamoyl and uninterrupted or interrupted by oxy, and
R6xe2x80x2 is hydrogen, C1-C6-alkoxy with or without oxy interruption in its alkyl radical, mono- or di(C1-C6)alkylamino, C1-C6-alkoxycarbonyl, carbamoyl, mono- or di(C1-C6)alkylcarbamoyl, sulfamoyl, mono- or di(C1-C6)alkylsulfamoyl.
The coupling step is carried out at a pH above 2, preferably within the range from 3 to 7. The desired pH may be set and, if necessary, corrected during the coupling reaction by adding, for example, ammonium or alkali metal bases, e.g., sodium hydroxide, sodium carbonate, sodium acetate, potassium hydroxide, potassium carbonate or potassium acetate. Usually, the end point of the reaction will be reached not more than 2 hours after completion of the addition. Chain termination is effected by coupling onto a coupling component devoid of a reactive terminus or by decomposing the diazonium compounds.
Depending on the choice of ratio for the starting materials, mixtures are obtained of various oligomers, among which the dimer fraction increases with increasing coupling component fraction. An approximately stoichiometric reaction of 1 mol of diamine V with 2 mol of coupling component IIIaxe2x80x2 provides predominantly the preferred dyes where n is 1. Separation into the individual dyes is possible in principle, but generally unnecessary, since the mixtures are found to have good application properties.
Coupling a diazo component obtained by diazotizing an amine of the formula VI
onto disazo dyes IV provides likewise preferred tetraazo dyes.
The amines VI are generally known and are described for example EP-A-0 159 549.
The dyes are very useful in the production of pulp-dyed, sized and unsized paper. They are likewise useful for dyeing paper by the dip process.
The dyeing of paper, leather or cellulose takes place according to methods known per se.
The novel dyes and their preparations color the papermaking wastewater only minimally, if at all, which is particularly favorable from the aspect of keeping the water courses clean. They are highly substantive, do not marble on paper and are substantially pH-insensitive. The dyeings on paper are notable for good lightfastness. On prolonged exposure to light the hue changes on-tone.
The basic azo dyes of the formula I of the invention can be used alone, in mixtures with each or one another and together with other cationic or anionic compounds in the form of their solutions or in the form of powders or granules. They are advantageously useful for dyeing or printing polymeric material, especially papery materials such as paper and paperboard, but also cellulose, cotton, leather, bast fibers, hemp, flax, sisal, jute, coir, straw or anionically modified fibers and also in inks, including printing inks.
In relation to the production of dye preparations comprising the novel dyes of the formula I, the use of polymers, such as polyacrylic acids, polyacrylic acid derivatives, polyvinylamines, polyvinylamides, polyvinyl acetates, polyvinyl alcohols, polyvinylpyrrolidones, polysiloxanes or copolymers of the respective monomers, must be emphasized. Similarly, oligomers of ethyleneimine, ethylene oxide or propylene oxide or derivatives thereof can be used.
The dyed papers, which exhibit good bleachability, are wetfast, not only with regard to water, but also with regard to milk, soapy water, sodium chloride solutions, fruit juices or sweetened mineral water, and are also stable to alcoholic drinks because of their good alcohol fastness.
The novel dyes can also be used for dyeing, padding or printing polyacrylonitrile textiles or anionically modified polyamide or polyester textiles.

Abstract: where R1, R2, R3, A1, A2, B1, B2, Anxe2x8ax96, n and K have the meaning given in the specification are prepared and used for the dyeing and printing of natural or synthetic substrates and mixtures thereof.


A sensor measures the interaction of an applied magnetic field to a sample surface that includes magnetic materials to determine whether the samples surface has been corroded. The sensor measures the magnetic force resulting from the interaction or the magnetic flux density to determine the content of magnetic material in localized regions of the sample surface. The sensor includes a cantilever beam with a strain gauge for measuring magnetic force. Alternatively, the sensor includes a magnetic flux density sensor to measure magnetic flux density.

1. Field of the Invention
This invention relates a method and apparatus for the sensing of magnetic properties and, more particularly, to a non-destructive testing device for detecting graphitization and localized corrosion in gray cast iron, ductile iron, ferrous alloys and other magnetic materials based on magnetic force or magnetic flux density measurements.
2. Description of the Related Art
Water main failures are very expensive for municipalities because they typically result in expenses associated with repair costs, flood damage, and loss of revenue to affected businesses. Water main failures also interrupt the operation of vital services, such as medical care and fire fighting operations. Currently, millions of dollars are spent annually by industry and by municipalities on the repair of failed components of the water distribution infrastructure, such as components that are made from gray cast iron or "gray iron" pipe.
The rate of municipal water main failure is expected to increase as the existing gray iron infrastructure continues to age. The cost of repairing damages caused by broken water mains (and subsequent flooding damage) may become an important item in many municipal budgets. The development of a non-destructive sensing technique to detect defects in the water distribution infrastructure to prevent catastrophic failure of water distribution infrastructure components would result in tremendous savings.
A non-destructive testing technique could be used in a program that is designed to detect localized corrosion before actual failures occur. A typical program would include identification of microstructure (gray iron, ductile iron, or other), identification of corrosion mechanisms, determination of the extent of internal and external corrosion (maximum and minimum wall thickness), determination of degradation and distribution of the magnetic properties of the metal, and an analysis of data and determination of preventative action. The monitoring of pipe corrosion would be continued for a few years beyond the application of corrosion control measures.
The metallurgy of gray iron is disclosed in detail in the publication entitled "Iron—A Unique Engineering Material," by D. E. Krause, Gray, Ductile and Malleable Iron Castings—Current Capabilities, ASTM STP 455, Philadelphia, Pa., ASTM: 1969, p. 3. The most important elements in gray iron, aside from iron, are carbon and silicon. The silicon content affects the carbon distribution in the metal.
Unlike the carbon in ductile iron and steel, which is disbursed as graphite spheroids and pearlite, respectively, the carbon in gray iron is present in flake form. These flakes form in the eutectic cell boundaries during cooling of the cast metal. The resulting graphite flakes form a continuous matrix throughout the gray iron.
A gray iron sample that includes an increased amount of silicon will have a decreased amount of carbon in the eutectic phase. Such a sample will have an increased amount of carbon in the form of pearlite and a decreased amount of graphite flakes. The lower content of graphite flakes results in an increase in tensile strength.
Typically, gray iron component failure is attributed to graphitic corrosion or graphitization. Graphitization occurs when the metallic constituents of gray iron are selectively removed or converted into corrosion products. Graphitization leaves behind the graphite matrix of the gray iron in the shape of the original casting. Graphitic corrosion is particularly insidious because graphitized pipe may appear perfectly sound upon visual inspection despite being embrittled and prone to premature failure under load.
Graphitic corrosion is one example of the dealloying of a metal. During dealloying, one component of an alloy is selectively dissolved, leaving other components behind. The preferential attack on iron in gray iron results from the fact that graphite is located at a highly noble or corrosion resistant position in the galvanic activity series. The relative position of two metals in the galvanic activity series determines which will most readily participate in electrochemical reactions, such as corrosion.
Pipes that are subject to graphitization may appear sound and may conduct water adequately. However, the metallic portion of a pipe wall may be significantly thinner in various places along the wall. Graphitized regions of the pipe wall will be brittle and subject to failure under load as the result of temperature variation, heavy traffic, or shock.
The galvanizing of iron with zinc inhibits corrosion because iron is nobler in the activity series than zinc. Therefore the zinc plating layer is preferentially attacked, greatly extending the service life of the iron substrate.
Similarly, graphite is far more noble than iron, so that the graphite matrix within the gray iron can act as the cathode in an electrochemical reaction under the right conditions of soil composition and moisture. The iron in gray iron samples that are subject to an electrochemical reaction will undergo anodic attack. In such samples, the graphite matrix will survive, while the iron is dissolved away.
The properties of iron that could be used to detect graphitization or other localized corrosion phenomena include ductility, electrical resistivity, or acoustic properties, such as ultrasonic sound velocity or attenuation. However, assessing ductility, by nature, involves destruction of the sample. Acoustical methods cannot be used with coated pipes due to the fact that it requires surface contact with bare, clean metal.
The publication entitled "Development of a Cast Iron Graphitization Measurement Device," NYGAS Technology Briefs, Issue 99-690-1, January 1999, discloses a meter that uses eddy currents to measure the electrical resistivity of a sample surface. Eddy current methods require sophisticated control circuitry and precisely tuned components. The eddy current device necessarily consumes a considerable amount of power to generate the RF signal that it uses to induce eddy currents in the sample.
Ultrasonic measurement of acoustic properties requires a very clean interface between the probe and the pipe for purposes of acoustic transmission and impedance matching, so that it is poorly suited for use with exposed, buried pipe which is often wet or dirty. Accordingly, there is a need for an improved non-destructive testing method and apparatus for detecting the graphitization of gray iron.

Non-destructive testing apparatus for the detection of corrosion