HK1030961B - Flame-resistant polycarbonate abs moulding materials - Google Patents

Description

Flame-resistant polycarbonate/ABS moulding materials

The present invention relates to polycarbonate/ABS moulding compositions which are rendered flame-resistant with organic phosphorus compounds, have an excellent series of mechanical properties, in particular an excellent stress cracking resistance, and are flame-resistant.

EP-A-0174493 describes flame-retardant halogen-containing polymer mixtures composed of aromatic polycarbonate, styrene-containing graft copolymer, monophosphate and ｃA special polytetrafluoroethylene formulation. Although these mixtures are sufficient in terms of flame retardancy and mechanical properties, the surface properties of the molded articles are impaired when high processing temperatures are used. Molded articles also exhibit some disadvantages in terms of stress crack resistance.

EP-A0363608 describes polymer mixtures composed of aromatic polycarbonate, styrene-containing copolymer or graft copolymer and oligomeric phosphates as flame-retardant additives. The stress cracking resistance of these mixtures is usually not sufficient to produce thin-walled house parts.

EP-A771851 describes molding compositions comprising aromatic polycarbonate, graft copolymer based on diene rubber, SAN copolymer, phosphoric ester and tetrafluoroethylene polymer, the polycarbonate having various molecular weights. However, very fine inorganic compounds are not described as a component of the molding compositions.

The object of the present invention was to provide flame-retardant polycarbonate/ABS moulding compositions which have excellent stress cracking resistance and very good processing properties and are suitable in particular for the production of thin-walled household parts.

It has surprisingly been found that polycarbonate/ABS moulding compositions having a significantly improved stress cracking resistance can be produced by using specific mixtures of polycarbonates, each having a distinctly different solution viscosity, in combination with very fine inorganic compounds.

Accordingly, the present invention provides flame-retardant thermoplastic molding compositions comprising

A.5 to 95, preferably 10 to 90, particularly preferably 20 to 80 parts by weight of a mixture of two aromatic polycarbonates A.1 and A.2 having different solution viscosities

A.1 has a relative solution viscosity of 1.18 to 1.24,

a.2 has a relative solution viscosity of 1.24 to 1.34

The difference in relative solution viscosity of A.1 and A.2 is equal to or greater than 0.06,

wherein one or more further polycarbonates can be added to the mixture of A.1 and A.2,

b.0 to 50, preferably 1 to 30, particularly preferably 2 to 25 parts by weight of a (co) polymer composed of one or at least two ethylenically unsaturated monomers,

c.0.5 to 60, preferably 1 to 40, particularly preferably 2 to 30 parts by weight of a graft polymer obtainable by graft polymerization of at least two monomers selected from the group consisting of chloroprene, butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth) acrylates having 1 to 18 carbon atoms in the alcohol component,

d.0.5 to 20 parts by weight, preferably 1 to 18 parts by weight, particularly preferably 2 to 15 parts by weight, of phosphorus compounds of the formula (I)

Wherein

R¹、R²、R³And R⁴Independently of one another, represents optionally halogenated C₁-C₈-alkyl, or C₅-C₆-cycloalkyl, C₆-C₂₀-aryl or C₇-C₁₂Aralkyl, each optionally substituted by halogen and/or C₁-C₄-an alkyl substitution,

n represents independently of one another 0 or 1,

n is 0 to 30 and

x represents a mono-or polynuclear aromatic radical having 6 to 30 carbon atoms,

e.0.05 to 5 parts by weight, preferably 0.1 to 1 part by weight, particularly preferably 0.1 to 0.5 part by weight, of fluorinated polyolefins,

f.0.01 to 50 parts by weight, preferably 0.1 to 10 parts by weight (per 100 parts by weight of A to E) of very fine inorganic compounds having an average particle diameter of less than or equal to 200nm, preferably less than or equal to 150nm, in particular less than or equal to 100 nm.

The sum of all parts by weight A + B + C + D + E + F is 100.

The molding compositions according to the invention are, owing to their excellent flame resistance, stress cracking resistance and very good processability, particularly suitable for the preparation of thin-walled moldings (room parts for data processing elements) in which high processing temperatures and pressures cause significant strains on the materials used.

Component A

The thermoplastic aromatic polycarbonates suitable according to the invention for use as component A are based on bisphenols of the formula (II), or alkyl-substituted dihydroxyphenylcycloalkanes of the formula (III),

in the formula (II)

A represents a single bond or C₁-C₅Alkylene radical, C₂-C₅- (1, 1-) alkylene, C₅-C₆-cyclo (1, 1-) alkylene, -S-, -SO₂-, -O-, -CO-or C₆-C₁₂An arylene group, a halogenated arylene group,

b represents chlorine or bromine, and the compound is represented by,

x is 0, 1 or 2 and

p is 1 or 0, and p is a linear alkyl group,

in the formula (III)

R¹¹And R¹²Are each, independently of the others, hydrogen; halogen, preferably chlorine or bromine; or C₁-C₈Alkyl, preferably C₁-C₄-an alkyl group; c₅-C₆-a cycloalkyl group; c₆-C₁₀-aryl, preferably phenyl; or C₇-C₁₂Aralkyl, preferably phenyl-C₁-C₄-an alkyl group, in particular a benzyl group,

m is an integer from 4 to 7, preferably 4 or 5,

for each Z, R¹³And R¹⁴May be selected respectively and independently of one another represent hydrogen or C₁-C₆-alkyl, preferably hydrogen, methyl or ethyl, and

z represents carbon, with the proviso that R is on at least one atom Z¹³And R¹⁴Simultaneously represents an alkyl group.

Suitable diphenols of the formula (II) are, for example, hydroquinone, resorcinol, 4' -dihydroxydiphenyl, 2-bis- (4-hydroxyphenyl) -propane, 2, 4-bis- (4-hydroxyphenyl) -2-methylbutane, 1-bis- (4-hydroxyphenyl) -cyclohexane, 2-bis- (3-chloro-4-hydroxyphenyl) -propane, 2-bis- (3, 5-dibromo-4-hydroxyphenyl) -propane.

Preferred diphenols of the formula (II) are 2, 2-bis- (4-hydroxyphenyl) -propane, 2-bis- (3, 5-dibromo-4-hydroxyphenyl) -propane and 1, 1-bis- (4-hydroxyphenyl) -cyclohexane.

Preferred bisphenols of formula (III) are dihydroxydiphenylcycloalkanes containing 5 or 6 ring carbon atoms in the cycloaliphatic radical (m ═ 4 or 5 in formula (III)) such as bisphenols of the formula:

of these, 1-bis- (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane (formula (IIIa)) is particularly preferred.

Polycarbonates suitable as component A according to the invention can be branched in a known manner, i.e.preferably by incorporating from 0.05 to 2.0 mol%, relative to the sum of the diphenols used, of compounds having three or more functional groups, such as those having three or more phenolic groups, for example phloroglucinol, 4, 6-dimethyl-2, 4, 6-tris (4-hydroxyphenyl) -hept-2-ene, 4, 6-dimethyl-2, 4, 6-tris (4-hydroxyphenyl) -heptane, 1, 3, 4-tris- (4-hydroxyphenyl) -benzene, 1, 1, 1-tris- (4-hydroxyphenyl) -ethane, tris- (4-hydroxyphenyl) -phenylmethane, 2-bis- (4, 4-bis- (4-hydroxyphenyl) -cyclohexyl) -propane, 2, 4-bis- (4, 4-bis-4-hydroxyphenyl) -isopropyl) -phenol, 2, 6-bis- (2-hydroxy-5' -methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2, 4-dihydroxyphenyl) -propane, hexa- (4- (4-hydroxyphenyl-isopropyl) -phenyl) -phthalate, tetrakis- (4-hydroxyphenyl) -methane, tetrakis- (4- (4-hydroxyphenyl-isopropyl) -phenoxy) -methane and 1, 4-bis- ((4', 4 "-dihydroxytriphenyl) -methyl) -benzene.

Some other trifunctional compounds are 2, 4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3, 3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2, 3-dihydroindole.

Preferred polycarbonates, in addition to bisphenol A homopolycarbonates, are bisphenol A copolycarbonates containing up to 15 mol%, relative to the sum of the moles of bisphenol, of 2, 2-bis- (3, 5-dibromo-4-hydroxyphenyl) -propane.

The aromatic polycarbonates of component A may be partially substituted by aromatic polyester carbonates.

The aromatic polycarbonates of component A may also contain polysiloxane blocks. The production thereof is described, for example, in DE-OS 3334872 and US-PS 3821325.

The aromatic polycarbonates and/or aromatic polyester carbonates according to component A are known in the literature or can be produced by methods known in the literature (for the production of aromatic polycarbonates see, for example, Schnell, "chemistry and Physics of polycarbonates", Interscience publishers, 1964 and DE-AS 1495626, DE-OS 2232877, DE-OS 2703376, DE-OS 2714544, DE-OS 3000610, DE-OS 3832396; for the production of aromatic polyester carbonates see, for example, DE-OS 3077934).

Aromatic polycarbonates and/or aromatic polyester carbonates are prepared, for example, by reacting bisphenols with carbonic acid halides, preferably phosgene; and/or with aromatic dicarboxylic acid dihalides, preferably benzene dicarboxylic acid dihalides, optionally using chain terminators and optionally using trifunctional or more than trifunctional branching agents.

The polycarbonates A.1 and A.2 preferably have the same structure, i.e.they consist of the same monomers.

It is particularly preferred that the polycarbonates A.1 and A.2 and optionally additionally the polycarbonate A consist of the same monomers, i.e.that they have the same chemical structure.

The additional polycarbonate is preferably added in an amount of 30% by weight (relative to the amounts of A.1 and A.2).

The amount of A.1 is from 5 to 95, preferably from 10 to 75, in particular from 10 to 35,% by weight, and the amount of A.2 is from 95 to 5, preferably from 90 to 25, in particular from 90 to 65,% by weight, based on the mixture of polycarbonates A.1 and A.2.

The mixtures of polycarbonates A.1 and A.2 are characterized in that the relative solution viscosity of A.1 is 1.181.24, the relative solution viscosity of A.2 is from 1.24 to 1.34, and the difference between the relative solution viscosities of A.1 and A.2 is greater than or equal to 0.06, in particular greater than or equal to 0.09, i.e.the relative solution viscosity of A.2 minus the relative solution viscosity of A.1 is greater than or equal to 0.06, in particular greater than or equal to 0.09. Relative solution viscosity is in CH₂Cl₂Measured at 25 ℃ and at a concentration of 0.5g/100ml of solvent.

One or both of the polycarbonate components A.1 or A.2 in the mixture may be recycled polycarbonate. Recycled polycarbonate is understood to be a product which has undergone one cycle of processing and use and from which adhering impurities have been substantially removed by means of special aftertreatment processes, suitable for further use.

Component B

The thermoplastic polymer B comprises (co) polymers of one or at least two ethylenically unsaturated monomers (vinyl monomers), such as styrene, alpha-methylstyrene, ring-substituted styrenes (for example halogen and/or alkyl ring-substituted), acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride, N-substituted maleimides and (meth) acrylates having 1 to 18 carbon atoms in the alcohol component.

The (co) polymers of component B are resin-like, thermoplastic and rubber-free. The molding compositions may also comprise different (co) polymers B.

Preferred vinyl (co) polymers B are (co) polymers composed of at least one monomer from the series (B.1) of styrene, alpha-methylstyrene, ring-substituted styrene and/or methyl methacrylate and at least one monomer from the series (B.2) of acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride and/or N-aryl-substituted maleimides.

The concentration of the monomers B.1 in the (co) polymers is preferably from 50 to 99, particularly preferably from 60 to 95,% by weight, and the concentration of the monomers B.2 is preferably from 1 to 50, particularly preferably from 40 to 5,% by weight.

Particularly preferred copolymers B are those composed of styrene and acrylonitrile and optionally methyl methacrylate, of alpha-methylstyrene and acrylonitrile and optionally methyl methacrylate, or of styrene and alpha-methylstyrene and acrylonitrile and optionally methyl methacrylate.

The (co) polymers according to component B are known and can be produced by free-radical polymerization, in particular by emulsion, suspension, solution or bulk polymerization. The molecular weight Mw (weight average, determined by light scattering or sedimentation) of the (co) polymer according to component B is preferably 15,000-200,000.

The (co) polymers B which are particularly preferred according to the invention are also random copolymers of styrene and maleic anhydride, preferably prepared by continuous bulk or solution polymerization with incomplete conversion of the corresponding monomers.

The ratio of the two components in suitable random copolymers according to the invention and composed of styrene and maleic anhydride can be varied within wide limits. The preferred concentration of maleic anhydride is 5 to 25 weight percent.

The polymer may also contain ring-substituted styrenes such as p-methylstyrene, 2, 4-dimethylstyrene and other substituted styrenes such as alpha-methylstyrene in place of styrene.

The molecular weight (number average Mn) of the random copolymers of component B consisting of styrene and maleic anhydride can be varied within wide limits according to the invention. The preferred range is 60,000-200,000. The intrinsic viscosity of these products is preferably in the range from 0.3 to 0.9 (measured in dimethylformamide at 25 ℃; see Hoffmann, Kr * mer, Kuhn, Polymer analysis I, Stuttgart1977, 316 and the following pages).

Component C

Component C according to the invention is a graft polymer. They comprise graft copolymers having rubber-elastic properties, obtainable essentially from at least two of the following monomers: chloroprene, 1, 3-butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth) acrylates having 1 to 18 carbon atoms in the alcohol component; i.e.for example in "organic chemistry methods" (Houben-Weyl), volume 14/1, Georg Thieme Verlag Press, Stuttgart 1961, page 393-406 and "toughened plastics" in C.B.Bucknall, using the polymers described in scientific Press, London 1977. Preferred polymers C are partially crosslinked and have a gel content of more than 20% by weight, preferably more than 40% by weight, in particular more than 60% by weight.

Preferred graft polymers C include:

c.15-95, preferably 30-80 parts by weight of a mixture comprising:

c.1.150-99 parts by weight of styrene, alpha-methylstyrene, halogen-or methyl ring-substituted styrene, methyl methacrylate or mixtures of these compounds and

c.1.21-50 weight portions of acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride and C₁-C₄Alkyl or phenyl-N-substituted maleimides or mixtures of these compounds grafted on

C.25-95, preferably 20-70 parts by weight of a diene and/or alkylacrylate based polymer having a glass transition temperature below-10 ℃.

Preferred graft polymers C are, for example, substrates c.2 grafted with styrene and/or acrylonitrile and/or alkyl (meth) acrylates, such as polybutadiene, butadiene/styrene copolymers and acrylate rubbers, i.e. copolymers of the type described in DE-OS 169473 (US-PS 3564077); or polybutadiene, butadiene/styrene or butadiene/acrylonitrile copolymers, polyisobutylene or polyisoprene grafted with alkyl acrylates or methacrylates, vinyl acetate, acrylonitrile, styrene and/or other alkylstyrenes, as described in DE-OS 2348377 (US-PS 3919353).

Examples of particularly preferred polymers C are ABS polymers, as described, for example, in DE-OS 2035390 (US-PS 3644574) or DE-OS 2248242 (GB-PS 1409275).

Particularly preferred graft polymers C are obtained by grafting reaction of the following compounds:

alpha to the graft polymer C, 10 to 70, preferably 15 to 50, in particular 20 to 40 wt.% of at least one (meth) acrylate or 10 to 70, preferably 15 to 50, in particular 20 to 40 wt.% of a mixture of 10 to 50, preferably 20 to 35 wt.% (relative to the mixture) of acrylonitrile or (meth) acrylate and 50 to 90, preferably 65 to 80 wt.% (relative to the mixture) of styrene as an outer graft C.1,

beta to the graft polymer C, 30 to 90, preferably 50 to 85, in particular 60 to 80 wt.% of a butadiene polymer (containing at least 50 wt.% of butadiene groups relative to beta) as graft base C.2,

wherein the gel content of the graft base beta is preferably at least 70 wt.% (measured in toluene), the degree of grafting G is 0.15 to 0.55 and the mean particle diameter d of the graft polymer C.2₅₀Is 0.05-2 μm, preferably 0.1-0.6 μm.

The (meth) acrylic acid ester α is an ester of acrylic acid or methacrylic acid with a monohydric alcohol having from 1 to 18 carbon atoms. Methyl, ethyl and propyl methacrylate, n-butyl acrylate, t-butyl acrylate and t-butyl methacrylate are particularly preferred.

In addition to the butadiene groups, the grafting base β may contain up to 50% by weight, relative to β, of other ethylenically unsaturated monomers, such as styrene, acrylonitrile, acrylic or methacrylic esters having 1 to 4 carbon atoms in the alcohol component (e.g. methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate), vinyl esters and/or vinyl ethers. The preferred grafting base β consists of pure polybutadiene.

The degree of grafting G is the weight ratio between the grafted monomer and the grafting base and is dimensionless.

Average particle size d₅₀The particles each account for 50 wt% of the diameter above and below this diameter. It can be determined by ultracentrifuge measurement techniques (W.Scholtan, H.Lange, Kolloid, Z.und Z.Polymer 250(1972), 782-796).

Particularly preferred polymers C are also graft polymers of, for example, the following compounds:

tau.20-90 wt.%, relative to component C, of an acrylate rubber having a glass transition temperature < -20 ℃, as graft base C.2 and

10-80% by weight, relative to component C, of at least one polymerizable ethylenically unsaturated monomer as graft monomer C.1.

The acrylate rubber tau in the polymer C is preferably a polymer of an alkyl acrylate, optionally containing up to 40 wt.% (referred to tau) of a further polymerizable compoundAnd (3) synthesizing an ethylenically unsaturated monomer. Preferred polymerizable acrylates include C₁-C₈Alkyl esters, such as methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; haloalkyl esters, preferably halo-C₁-C₈Alkyl esters, such as chloroethyl acrylate, and mixtures of these monomers.

To crosslink the product, monomers with more than one polymerizable double bond may be copolymerized. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having 3 to 8 carbon atoms with unsaturated monohydric alcohols having 3 to 12 carbon atoms or saturated polyols having 2 to 4 OH groups and 2 to 20 carbon atoms, such as ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds such as trivinyl and triallyl cyanurate; polyfunctional vinyl compounds such as di-and tri-vinylbenzenes; and triallyl phosphate and diallyl phthalate.

Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds containing at least three ethylenically unsaturated groups.

Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, trivinyl cyanurate, triacryloylhexahydro-s-triazine, triallylbenzenes.

The amount of crosslinking monomer is preferably from 0.02 to 5, in particular from 0.05 to 2,% by weight, based on the graft base τ.

In the case of ring-crosslinking monomers containing at least three ethylenically unsaturated groups, it is advantageous to limit the amount of graft base τ to less than 1% by weight.

Preferred "other" polymerizable ethylenically unsaturated monomers which may optionally also be used in addition to the acrylate for the production of the graft base tau are, for example, acrylonitrile, styrene, alpha-methylstyrene, acrylamide, vinyl-C₁-C₆Alkyl ethers, methyl methacrylate, butadiene. Preferred acrylate rubbers as graft base tauIs an emulsion polymer having a gel content of at least 60 wt%.

Further suitable graft bases according to C.2 are silicone rubbers with graft-active sites, as described in DE-OS 3704657, DE-OS 3704655, DE-OS 3631540 and DE-OS 3631539.

The gel content of the grafting base C.2 was determined at 25 ℃ in dimethylformamide (M.Hoffmann, H.Kr * mer, R.Kuhn, Polymer analysis I and II, George Thieme-Verlag Press, Stuttgart 1977).

The graft polymers C can be produced by known processes, such as the bulk, suspension, emulsion or bulk-emulsion process.

Since it is known that the graft monomers are not completely grafted onto the graft base in the grafting reaction, graft polymers C are also understood according to the invention as meaning products which are obtained by polymerizing the graft monomers in the presence of the graft base.

Component D

The inventive molding compositions comprise at least one organic phosphorus compound or a mixture of organic phosphorus compounds of the formula (I) as flame retardant

In the formula, R¹、R²、R³And R⁴Have the same meaning as described above. R¹、R²、R³And R⁴Preferably represents C₁-C₄Alkyl or phenyl, naphthyl or phenyl-C₁-C₄-an alkyl group. For aromatic radicals R¹、R²、R³And R⁴They may be substituted by halogen and/or alkyl (preferably C)₁-C₄-alkyl) substitution. Particularly preferred aryl radicals are cresyl, phenyl, xylenyl, propylphenyl or butylphenyl and the corresponding brominated or chlorinated derivatives thereof.

In formula (I), X represents a mono-or polynuclear aromatic radical having 6 to 30 carbon atoms. Preference is given to bisphenol derived from formula (II) such as bisphenol A, resorcinol or hydroquinone or chlorinated or brominated derivatives thereof.

In formula (I), n may be 0 or 1 independently of one another, preferably n is 1.

N may be any value from 0 to 30.

In the case of mixtures of phosphorus compounds, N can be taken on an average value of from 0 to 30, preferably from 0.3 to 20, particularly preferably from 0.5 to 10, very particularly preferably from 0.5 to 6. Monophosphorus compounds and/or oligomeric phosphorus compounds may also be present in the mixture. When N is 0, formula (I) describes monophosphorus compounds.

The phosphorus compounds of the formula (I) are preferably tributyl phosphate, tris- (2-chloroethyl) -phosphate, tris- (2, 3-dibromopropyl) -phosphate, triphenyl phosphate, tricresyl phosphate, diphenylcresyl phosphate, diphenyloctyl phosphate, diphenyl-2-ethylcresyl phosphate, tris- (isopropylphenyl) -phosphate, halogen-substituted aryl phosphates, dimethyl methylphosphonate, diphenyl methylphosphonate, diethyl phenylphosphonate, triphenylphosphine oxide and/or m-phenylene-bis (diphenyl) phosphate.

Mixtures of phosphorus compounds of the formula (I) having N values of from 0.5 to 10, in particular from 0.5 to 6, are preferred.

The mono-and oligomeric phosphorus compounds of the formula (I) in the mixture are preferably selected in such a way that a synergistic effect is obtained. The mixture generally consists of 10 to 90 wt.% of dimeric and/or oligomeric compounds and 90 to 10 wt.% of monophosphorus compounds, preferably of the formula (I). Preferably, the monophosphorus compound is mixed with a complementary amount of the oligophosphorus compound in the range from 12 to 50, preferably from 14 to 40, in particular from 15 to 40,% by weight.

Phosphorus compounds according to component D are known (see, for example, EP-A363608, EP-A640655) or can be prepared in a similar manner by known methods (see, for example, Ullmanns Encyklopadie der Technischen Chemie, Vol. 18, p. 301 and p. afterwards, 1979; Houben-Weyl, Methoden der Organischen Chemie, Vol. 12/1, p. 43; Bei nstein, Vol. 6, p. 177).

Component E

Fluorinated polyolefins E are high molecular weight compounds and have glass transition temperatures in excess of-30 ℃ and generally in excess of 100 ℃. The fluorine content thereof is preferably from 65 to 76, in particular from 70 to 76,% by weight, and the average particle diameter d₅₀Is 0.05-1000, preferably 0.08-20 μm. In general, the fluorinated polyolefins E have a density of from 1.2 to 2.3g/cm³。

Preferred fluorinated polyolefins E are polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene/hexafluoropropylene copolymers and ethylene/tetrafluoroethylene copolymers.

Fluorinated polyolefins are known (cf. Schildknecht "vinyl and related polymers", John Wiley & Sons, Inc., New York, 1962, pp.484-494; Wall's "fluoropolymers", Wiley Interscience, John Wiley & Sons, Inc., New York, Vol.13, 1970, pp.623-654; "modern plastics encyclopedia", 1970-1971, 47, 10A, 10.1970, McGraw-Hill, Inc., New York, 134 and 774; modern plastics encyclopedia ", 1975-1976, 1975, 10.1975, pp.52, 10A, McGraw-Hill, New York, pp.27, 28 and 472 and US-PS 3671487, 3723373 and 3838092).

They can be produced by known methods, for example by using free-radical-forming catalysts such as sodium, potassium or ammonium peroxodisulfate in an aqueous medium at from 7 to 71 kg/cm²And a temperature of from 0 to 200 c, preferably from 20 to 100 c. (see, for example, U.S. Pat. No. 2,2393967 for further details). Depending on the form used, the density of these materials may be from 1.2 to 2.3g/cm³The average particle size is 0.05-1000 μm.

Preferred fluorinated polyolefins E according to the invention are tetrafluoroethylene polymers and have average particle diameters of 0.05 to 20 μm, preferably 0.08 to 10 μm, and densities of 1.2 to 1.9g/cm³And is preferably used as a coagulated mixture of tetrafluoroethylene polymer E emulsion and graft polymer C emulsion.

Suitable tetrafluoroethylene polymer emulsions are commercially available products and are available, for example, from DuPont as Teflon @^*And 30N is sold.

Suitable fluorinated polyolefins E which can be used in powder form have an average particle diameter of 100-1000 μm and a density of 2.0 to 2.3g/cm³The tetrafluoroethylene polymer of (1).

To prepare a coagulated mixture of C and E, an aqueous emulsion (latex) of a graft polymer C having an average latex particle diameter of 0.05 to 2 μm, in particular 0.1 to 0.6 μm, is first mixed with a fine emulsion of a tetrafluoroethylene polymer E having an average particle diameter of 0.05 to 20 μm, in particular 0.08 to 10 μm, in water. Suitable tetrafluoroethylene polymer emulsions generally have solids contents of from 30 to 70% by weight, in particular from 50 to 60% by weight.

The solids content of the aqueous emulsion of the graft polymer C is from 25 to 60% by weight, preferably from 30 to 45% by weight, in particular from 30 to 35% by weight.

The data given for the quantities in the description of component C do not include the content of graft polymer in the coagulated mixture of graft polymer and fluorinated polyolefin.

The weight ratio of graft polymer C to tetrafluoroethylene polymer E in the emulsion mixture is 95: 5 to 60: 40. The emulsion mixture is coagulated in a known manner, for example by spray drying, freeze drying or coagulation by addition of inorganic or organic salts, acids, bases or water-miscible organic solvents such as alcohols, ketones, preferably at from 20 to 150 ℃ and in particular from 50 to 100 ℃. If desired, drying may be carried out at 50 to 200 ℃ and preferably 70 to 100 ℃.

Component F

Very fine inorganic compounds according to component F consist of compounds of one or more metals of main groups 1 to 5 and sub-groups 1 to 8, preferably main groups 2 to 5 or sub-groups 4 to 8, particularly preferably main groups 3 to 5 or sub-groups 4 to 8 of the Mendeleev's periodic Table of the elements with at least one element selected from the group consisting of oxygen, sulfur, boron, phosphorus, carbon, nitrogen, hydrogen or silicon.

Preferred compounds are, for example, oxides, hydroxides, hydrated oxides, sulfates, sulfites, sulfides, carbonates, carbides, nitrates, nitrites, nitrides, borates, silicates, phosphates, hydrides, phosphites or phosphonates.

Preferred very fine inorganic compounds are, for example, TiN, TiO₂，SnO₂，WC，Zn0，Al₂O₃，AlO(OH)，ZrO₂，Sb₂O₃，SiO₂Iron oxide, Na₂SO₄，BaSO₄Vanadium oxide, zinc borate, silicates such as aluminum silicate, magnesium silicate, and mono-, di-, or three-dimensional silicates. Mixtures and doped compounds may also be used. And these very small particles can be surface modified with organic molecules to obtain better compatibility with the matrix. Hydrophobic or hydrophilic organic surfaces can be obtained in this way.

The mean particle diameter is less than or equal to 200nm, preferably less than or equal to 150nm, in particular from 1 to 100 nm.

Particle size and particle diameter always mean the average particle diameter d₅₀Determined by the ultracentrifuge measurement method according to Kolloid-Z.und Z.Polymer 250(1972), 782-796, W.Scholtan et al.

The inorganic compounds can be used as powders, slurries, sols, dispersions or suspensions. Powders can be obtained by precipitation from dispersions, sols or suspensions.

The powder can be incorporated into the thermoplastic by conventional methods, for example by direct mixing or extrusion of the molding composition components and the very finely divided inorganic powder. A preferred method is to produce a masterbatch formulation, for example a dispersion of component B or C co-precipitated together with a dispersion, suspension, slurry or sol of a very fine inorganic material in a flame retardant additive, other additive, monomer, solvent or thermoplastic a.

The moulding compositions according to the invention may comprise at least one of the conventional additives such as lubricants and mould release agents, nucleating agents, antistatic agents, stabilisers and also dyes and pigments.

The moulding compositions according to the invention may also comprise flame-retardant compounds other than compounds of the formula (I) in amounts of up to 20 parts by weight. Flame retardants with a synergistic effect are preferred. Compounds are listed below as additional flame retardants: organic halides such as decabromobisphenyl ether, tetrabromobisphenol, inorganic halides such as ammonium bromide, nitrogen compounds such as melamine, melamine formaldehyde resins or siloxane compounds. The moulding compositions according to the invention may optionally comprise inorganic substances other than the inorganic compounds F, such as inorganic hydroxides, for example magnesium hydroxide and aluminium, such as aluminium oxide, antimony oxide, barium metaborate, hydroxoantimonate, zirconium oxide, zirconium hydroxide, molybdenum oxide, ammonium molybdate, zinc borate, ammonium borate and tin oxide.

The molding compositions according to the invention comprising components A to F and optionally further known additives such as stabilizers, dyes, pigments, lubricants and mold release agents, nucleating agents and antistatic agents are produced by mixing the particular components in a known manner and melt compounding or melt extrusion at 200-300 ℃ in conventional equipment such as internal mixers, extruders and twin-screw extruders, where component E is preferably used in the form of the abovementioned coagulated mixture.

The individual components can be mixed in a known manner, in fact at temperatures of about 20 c (room temperature) or more, either sequentially or simultaneously.

The molding compositions of the invention can be used to prepare a variety of molded articles. In particular, the molded articles can be produced by injection molding. Examples of producible molded articles are: various household parts, for example household articles such as juice makers, coffee makers, blenders, office machines such as computers, printers, monitors or copiers, or panels of building parts and motor vehicle parts. They can also be used in electrical engineering components, since they have very good electrical properties.

These molding compositions are particularly suitable for the production of thin-walled molded articles (for example room parts for data processing elements) in which the plastics used are required to meet particularly high restrictions with regard to flow behavior and stress cracking resistance.

Another form of processing is the production of moulded articles by thermoforming from previously prepared sheets or films.

The present invention therefore also provides the use of the molding compositions according to the invention for the production of molded articles of any type, preferably those mentioned above, and also molded articles made from the molding compositions of the invention.

Examples

Component A

A

Linear polycarbonate based on bisphenol A with a relative solution viscosity of 1.252, viscosity being CH₂Cl₂Measured at 25 ℃ and at a concentration of 0.5g/100ml of solvent.

A.1

Linear polycarbonate based on bisphenol A with a relative solution viscosity of 1.284, the viscosity being CH₂Cl₂Measured at 25 ℃ and at a concentration of 0.5g/100ml of solvent.

A.2

Linear polycarbonate based on bisphenol A with a relative solution viscosity of 1.200, viscosity being CH₂Cl₂Measured at 25 ℃ and at a concentration of 0.5g/100ml of solvent.

Component B

Styrene/acrylonitrile copolymer having a styrene/acrylonitrile ratio of 72: 28 and an intrinsic viscosity of 0.55dl/g (measured in dimethylformamide at 20 ℃).

Component C

45 parts by weight of a copolymer of styrene and acrylonitrile in a ratio of 72: 28 in 55 parts by weight of particulate crosslinked polybutylene terephthalateOlefinic rubber (average particle diameter d)₅₀═ 0.4 μm), produced by emulsion polymerization.

Component D

Component E

Tetrafluoroethylene polymer as a coagulated mixture of an SAN graft polymer emulsion according to component C in water and a tetrafluoroethylene polymer emulsion in water. The weight ratio of graft polymer C to tetrafluoroethylene polymer E in the mixture is 90% by weight to 10% by weight. The tetrafluoroethylene polymer emulsion has a solids content of 60 wt.% and an average particle diameter of 0.05 to 0.5. mu.m. The SAN graft polymer emulsion had a solids content of 34% by weight and an average latex particle diameter of 0.4. mu.m.

Preparation of E

The tetrafluoroethylene polymer emulsion (Teflon 30N, DuPont) was mixed with the SAN graft polymer C emulsion and stabilized with 1.8% by weight, based on polymer solids, of a phenolic antioxidant. At 85-95 deg.C with MgSO₄The aqueous (epsom salt) solution and acetic acid coagulate the mixture at a pH of 4-5, filter and wash until substantially free of electrolytes. Most of the water was then centrifuged off and the mixture was dried to a powder at 100 ℃. This powder can then be compounded with the additional components in the equipment described above.

Component F

Pural 200, an alumina-aluminum hydroxide (Condea, Hamburg, Germany) was used as very fine inorganic compound. The average particle size of the product was about 50 nm.

Preparation and testing of the moulding compositions according to the invention

Components A to F were mixed in a 3L internal mixer. Molded articles were prepared in an injection molding machine of the Arburg 270E type at 260 ℃.

80X 10X 4mm at room temperature according to ISO 1801A method³Notched impact resistance was measured on the bars.

The Vicat B softening point was determined in accordance with DIN 53460.

At a bulk temperature of 260 ℃ at a temperature of 80X 10X 4mm³The bars were tested for stress cracking characteristics. A mixture of 60 vol% toluene and 40 vol% isopropanol was used as test medium. Pre-stretching the test body by an arc template and storing the pre-stretched test body in a test medium for 5 minutes at room temperature, wherein the pre-stretching degree is epsilon_x0.2-2.4%. The stress cracking properties were evaluated by fracture or crack formation as a function of the degree of pre-stretching.

The composition of the test materials and the resulting data are summarized in Table 1 below.

It can be seen from the table that the molding compositions of the invention have a very good combination of mechanical properties, in particular an unexpected improvement in stress crack resistance, and flame retardancy, compared with molding compositions which do not contain any very fine inorganic powder (component F).

TABLE 1 composition and Properties of polycarbonate/ABS moulding compositions

Examples	Comparative example 1	Comparative example 2	3 invention
				AA1A2BCDEF mold release agent (parts by weight)	79--555.53-0.5	-4930555.53-0.5	-4930555.531.00.5
ηrel	1.252	1.252	1.252
				Performance: Vicat/B120(° c) notched impact resistance: (kJ/m)2)	11444	11546	11546
Marquis crack screening 5 min/1.0% marquis crack screening 5 min/0.8% marquis crack screening 5 min/0.6% marquis crack screening 5 min/0.4%	BR3：14KR	BR5：00KR+OR	BR5∶00KR+OR
				MVI240℃/5kgml/10min	16.0	16.4	16.6
Combustion performance UL 94V (1.6mm)	V-2	nb*	V-0

^*non-flame retardant nb

Claims (15)

1. Flame-retardant thermoplastic molding compositions comprising

A.5 to 95 parts by weight of a mixture of two aromatic polycarbonates A.1 and A.2 having different solution viscosities

A.1 has a relative solution viscosity of 1.18 to 1.24,

a.2 has a relative solution viscosity of 1.24 to 1.34

The difference between the relative solution viscosities of A.1 and A.2 is equal to or greater than 0.06, the viscosities of A.1 and A.2 being in CH₂Cl₂Measured at 25 ℃ and at a concentration of 0.5g/100ml,

b.0 to 50 parts by weight of a (co) polymer composed of one or at least two ethylenically unsaturated monomers from the group consisting of styrene, alpha-methylstyrene, ring-substituted styrene, acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride, N-substituted maleimide and (meth) acrylates having from 1 to 18 carbon atoms in the alcohol component,

0.5 to 60 parts by weight of a graft polymer obtained by graft polymerization of at least two monomers selected from the group consisting of chloroprene, 1, 3-butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth) acrylates having 1 to 18 carbon atoms in the alcohol component,

d.0.5 to 20 parts by weight of a phosphorus compound of the formula (I)

Wherein

R¹、R²、R³And R⁴Independently of one another, represents optionally halogenated C₁-C₈-alkyl, or C₅-C₆-cycloalkyl, C₆-C₂₀-aryl or C₇-C₁₂Aralkyl, each of which may optionally be substituted by halogen and/or C₁-C₄-an alkyl substitution,

n represents independently of one another 0 or 1,

n is 0 to 30 and

x represents a mono-or polynuclear aromatic radical having 6 to 30 carbon atoms,

e.0.05 to 5 parts by weight of a fluorinated polyolefin,

F.0.01 to 50 parts by weight, per 100 parts by weight of A to E, of an inorganic compound having an average particle diameter of less than or equal to 200nm, selected from SnO₂，ZnO，Al₂O₃，AlO(OH)，Sb₂O₃，SiO₂Zinc borate, Na₂SO₄Vanadium oxide and silicates.

2. Moulding compositions according to claim 1, characterized in that N in formula (I) has a value of 0.3 to 20.

3.A molding composition according to claim 1, wherein component B is a (co) polymer of one or at least two ethylenically unsaturated monomers selected from the group consisting of styrene, α -methylstyrene, ring-substituted styrene, acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride, N-substituted maleimide and (meth) acrylates having from 1 to 18 carbon atoms in the alcohol component.

4. A molding composition according to claim 1, wherein R in the formula (I)¹、R²、R³And R⁴Independently of one another represent C₁-C₄Alkyl or phenyl, naphthyl or phenyl-C₁-C₄-an alkyl group, each group optionally being substituted by halogen and/or alkyl, and X is derived from a bisphenol selected from bisphenol a, resorcinol or hydroquinone, optionally being chlorinated or brominated.

5. A molding composition according to claim 1, wherein the phosphorus compound of the formula (I) is selected from the group consisting of 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, halogen-substituted aryl phosphates, dimethyl methylphosphonate, diphenyl methylphosphonate, diethyl phenylphosphonate, triphenylphosphine oxide, tricresylphosphine oxide and/or m-phenylene-bis (diphenyl) phosphate.

6. Moulding compositions according to claim 1, wherein polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene/hexafluoroethylene and/or ethylene/tetrafluoroethylene copolymers are used as fluorinated polyolefins E.

7. A molding composition according to claim 1, which comprises, as component F, a compound of an element of main groups 1 to 5 and of subgroups 1 to 8 of the periodic Table of the elements with at least one element selected from the group consisting of oxygen, sulfur, boron, carbon, phosphorus, nitrogen, hydrogen or silicon.

8. A molding composition according to claim 1, wherein component F is selected from the group consisting of TiN, TiO₂，SnO₂，WC，ZnO，Al₂O₃，AlO(OH)，ZrO₂，Sb₂O₃，SiO₂Zinc borate, Na₂SO₄，BaSO₄Vanadium oxide and/or silicate.

9. A molding composition according to claim 1, wherein component F has an average particle diameter of less than or equal to 150 nm.

10. Moulding compositions according to one of claims 1 to 9, characterized in that they comprise 0.01 to 20% by weight, relative to the total moulding composition, of at least one further flame retardant which is different from component D.

11. A molding composition according to one of claims 1 to 9, comprising 10 to 90 parts by weight of component a), optionally 2 to 30 parts by weight of component B), 1 to 40 parts by weight of component C) and 1 to 18 parts by weight of component D), 0.1 to 1 part by weight of component E) and 0.1 to 10 parts by weight of component F).

12. Moulding compositions according to one of claims 1 to 9, comprising diene rubbers, acrylate rubbers, silicone rubbers or ethylene/propylene/diene rubbers as graft base.

13. Moulding compositions according to one of claims 1 to 9, comprising at least one additive from the group of stabilizers, pigments, mould release agents, flow promoters and/or antistatic agents.

14. Use of a molding composition according to one of claims 1 to 9 for the production of molded articles.

15. A molded article made from the molding composition according to one of claims 1 to 9.