WO2000041470A2

WO2000041470A2 - Method for producing polyester blends

Info

Publication number: WO2000041470A2
Application number: PCT/EP2000/000014
Authority: WO
Inventors: Martin Weber; Karlheinz Ulmerich; Doris Zeltner; Manfred Knoll
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-01-13
Filing date: 2000-01-04
Publication date: 2000-07-20
Also published as: WO2000041470A3; AU3275700A; DE19900891A1

Abstract

The invention relates to a method for producing stabilized polyester/polycarbonate blends, whereby; A) 40 to 99.9 wt. % of a polyester and B) 0.1 to 60 wt. % of a stabilizer containing phosphorous are mixed in the melt, are removed, cooled, and granulated, and component A' which is obtained in this manner is subsequently mixed with a polycarbonate C), is optionally mixed with a polyester A) and a rubber elastic polymerizate D), and is optionally mixed with additional additives E).

Description

Process for the production of polyester blends

description

The invention relates to an improved method for producing stabilized polyester / polycarbonate blends. Polymer blends are gaining increasing interest in technology because they offer tailor-made combinations of properties. Of particular interest are polymer blends made from incompatible polymers that have unusual combinations of properties.

Polymer mixtures based on polyesters and polycarbonates have been known for years (US 4,522,797, US 4,764,556, US 4,897,448, EP-A 180 648 and DE-A 33 02 124). The technically important products also contain impact modifiers to improve toughness, in particular at low temperatures, MBS modifiers, acrylate graft rubbers and ethylene copolymers with polar comonomers preferably being used.

From J. Devaux, P. Godard, J.P. Mercier, Polym. Closely. Seil., 22, 229 (1982) discloses that catalyst residues present in polyester lead to transesterification when melt compounding with polycarbonate. This creates copolymers that improve the mechanical properties of the resulting blends. At high processing temperatures, however, the transesterification becomes so rapid that the mechanical and thermal properties of the moldings produced are massively impaired. Furthermore, the molding compositions produced at high processing temperatures also have poor surface quality (streaks, discoloration).

Various investigations have also already been undertaken to improve the processing stability of polyester / polycarbonate blends.

EP-A 114 288 describes polyester / polycarbonate blends in which the MBS rubber added is premixed with a stabilizer in a preceding step. The measure improves the mechanical properties of the molding compositions. However, the stability of the molding compositions at a higher processing temperature is in need of improvement. EP-A 634 435 describes a catalyst mixture consisting of a Ti compound and a phosphorus compound, which can be used for the production of polyesters. Appropriately manufactured polyesters show a reduced tendency to transesterification in blends with polycarbonate. For example, US 4,452,932 proposes ortho-substituted aromatic hydroxy compounds as transesterification protection for polycarbonate / polybutylene terephthalic blends. At temperatures higher than 250 ° C, however, their effect is not sufficient.

The object of the present invention was therefore to provide an improved process for the production of polyester / polycarbonate blends, which is characterized in that

A) 40 to 99.9 wt .-% of a polyester and

B) 0.1 to 60% by weight of a phosphorus-containing stabilizer

mixes in the melt, discharges, cools and granulates and the component A 'thus obtained is then mixed with a polycarbonate C) and optionally a polyester A) and a rubber-elastic polymer D) and optionally further additives E).

Preferred embodiments can be found in the subclaims. Surprisingly, the premixing of a polyester, in particular in batch (concentrate) form, with a phosphorus-containing stabilizer leads to an improvement in stability, in particular at high temperatures, when processing to polyester / polycarbonate blends which have an improved surface and better mechanical properties .

Polyesters A) based on aromatic dicarboxylic acids and an aliphatic or aromatic dihydroxy compound are generally used.

A first group of preferred polyesters are polyalkylene terephthalates with 2 to 10 carbon atoms in the alcohol part.

Such polyalkylene terephthalates are known per se and are described in the literature. They contain an aromatic ring in the main chain, which comes from the aromatic dicarboxylic acid.

The aromatic ring can also be substituted, for example by halogen such as chlorine and bromine or by Cχ-C ₄ alkyl groups such as

Methyl, ethyl, i- or n-propyl and n-, i- or t-butyl groups. These polyalkylene terephthalates can be prepared in a manner known per se by reacting aromatic dicarboxylic acids, their esters or other ester-forming derivatives with aliphatic dihydroxy compounds.

Preferred dicarboxylic acids are 2,6-naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid or mixtures thereof. Up to 30 mol%, preferably not more than 10 mol%, of the aromatic dicarboxylic acids can be replaced by aliphatic or cycloaliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids and cyclohexanedicarboxylic acids.

Of the aliphatic dihydroxy compounds, diols having 2 to 6 carbon atoms, in particular 1, 2-ethanediol, 1,3-propanediol, 1, -butanediol, 1, 6-hexanediol, 1, 4-hexanediol, 1,4-cyclo- hexanediol, 1,4-cyclohexanedimethylanol and neopentyl glycol or mixtures thereof are preferred.

Polyalkylene terephthalates which are derived from alkanediols having 2 to 6 carbon atoms can be mentioned as particularly preferred polyesters (A). Of these, polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate or mixtures thereof are preferred in particular. Also preferred are PET and / or PBT, which contain up to 1% by weight, preferably up to 0.75% by weight.

Contain 1, 6-hexanediol and / or 2-methyl-l, 5-pentanediol as further monomer units.

The viscosity number of the polyesters (A) is generally in the range from 50 to 220, preferably from 80 to 160 (measured in a 0.5% by weight solution in a phenol / o-dichlorobenzene mixture (% by weight. 1: 1 at 25 ° C) according to ISO 1628.

Particularly preferred are polyesters whose carboxyl end group content is up to 100 meq / kg, preferably up to 50 meq / kg and in particular up to 40 meq / kg polyester. Such polyesters can be produced, for example, according to DE-A 44 01 055. The carboxyl end group content is usually determined by titration methods (e.g. potentiometry).

Particularly preferred molding compositions contain, as component A), a mixture of polyesters other than PBT, such as, for example, polyethylene terephthalate (PET). The proportion of, for example, polyethylene terephthalate is preferably in Mixture up to 50, in particular 10 to 30% by weight, based on 100% by weight of A).

Furthermore, it is advantageous to use PET recyclates (also called scrap-PET 5), optionally in a mixture with polyalkylene terephthalates such as PBT.

Recyclates are generally understood to mean:

10 1) so-called post industrial recyclate: this is production waste from polycondensation or processing e.g. Sprues in injection molding processing, approach goods in injection molding processing or extrusion or edge sections of extruded sheets or foils.

15

2) Post consumer recyclate: these are plastic items that are collected and processed by the end consumer after use. The most dominant item in terms of quantity are blow-molded PET bottles for

20 mineral water, soft drinks and juices.

Both types of recyclate can either be in the form of regrind or in the form of granules. In the latter case, the pipe cyclates are melted and granulated in an extruder after separation and cleaning. This usually makes the handling that

Free-flowing and easier to dose for further processing steps.

Both granulated and recycled material 30 can be used, the maximum edge length being 6 mm, preferably less than 5 mm.

Due to the hydrolytic cleavage of polyesters during processing (due to traces of moisture), it is advisable to predry the 35 recyclate. The residual moisture content after drying is preferably 0.01 to 0.7, in particular 0.2 to 0.6%.

Another group to be mentioned are fully aromatic polyesters which are derived from aromatic dicarboxylic acids and aromatic dihydroxy compounds.

Aromatic dicarboxylic acids which are suitable are the compounds already described for the polyalkylene terephthalates. Mixtures of 5 to 100 mol% isophthalic acid and 0 to 45 95 mol% terephthalic acid are preferred, in particular mixtures of approximately 80% Terephthalic acid with 20% isophthalic acid used to approximately equivalent mixtures of these two acids.

The aromatic dihydroxy compounds preferably have the general formula

in which Z represents an alkylene or cycloalkylene group with up to 8 C atoms, an arylene group with up to 12 C atoms, a carbonyl group, a sulfonyl group, an oxygen or sulfur atom or a chemical bond and in which m represents the value Has 0 to 2. The compounds I can also carry C ₁ -C ₆ -alkyl or alkoxy groups and fluorine, chlorine or bromine as substituents on the phenylene groups.

As the stem of these compounds, for example

Dihydroxydiphenyl,

Di (hydroxyphenyl) alkane,

Di - (hydroxyphenyl) cycloalkane, di - (hydroxyphenyl) sulfide,

Di (hydroxyphenyl) ether,

Di- (hydroxyphenyl) ketone, di - (hydroxyphenyl) sulfoxide,, α '-di (hydroxyphenyl) dialkylbenzene, di - (hydroxyphenyl) sulfone, di - (hydroxybenzoyl) benzene

Resorcinol and

Hydroquinone and their nuclear alkylated or nuclear halogenated

Called derivatives.

Of these will be

4,4'-dihydroxydiphenyl,

2, 4 -Di- (4'-hydroxyphenyl) -2-methylbutane α, α '-Di- (4-hydroxyphenyl) -p-diisopropylbenzene, 2, 2 -Di (3' -methyl -4 '-hydroxyphenyl) propane and 2,2-di- (3'-chloro-4'-hydroxyphenyl) propane,

as well as in particular

2,2-di (4'-hydroxyphenyl) propane

2,2-di (3 ', 5 -dichlorodihydroxyphenyl) propane, 1,1-di- (4'-hydroxyphenyl) cyclohexane,

3,4'-dihydroxybenzophenone,

4, 4 '-dihydroxydiphenylsulfone and

2,2-di (3 ', 5' -dimethyl-4 '-hydroxyphenyl) propane

or mixtures thereof are preferred.

Of course, mixtures of polyalkylene terephthalates and fully aromatic polyesters can also be used. These generally contain 20 to 98% by weight of the polyalkylene terephthalate and 2 to 80% by weight of the fully aromatic polyester.

Of course, polyester block copolymers such as copolyether esters can also be used. Products of this type are known per se and are described in the literature, for example in US Pat. No. 3,651,014. Corresponding products are also commercially available, for example Hytrel ^® (DuPont).

Suitable phosphorus-containing stabilizers are preferably organic phosphonites B) of the general formula I

wherein

m 0 or 1, n 0 or 1, y is an oxygen, sulfur or 1, 4-phenylene bridge or a bridge member of the formula -CH (R ² ) -; all R-0 and R ¹ -0 groups independently of one another, the residue of an aliphatic, alicyclic or aromatic alcohol which may contain up to three hydroxyl groups, but the hydroxyl groups are not arranged such that they form part of a phosphorus containing ring (referred to as monovalent RO groups), or two R-0 or R ¹ -0 groups bonded to a phosphorus atom, each independently of one another together with the remainder of an aliphatic, alicyclic or aromatic alcohol a total of up to three hydroxyl groups (referred to as bivalent R-0 or R ⁱ -O groups),

R ² hydrogen, Ci-Cg-alky! or a group of the formula COOR ³ and R ^{3 is} C ₈ alkyl.

Preference is given to at least one R 0 and at least R ¹ 0 group, a phenol radical which, in the 2 position, bears a sterically hindered group, in particular t-butyl radicals.

It is particularly preferred tetrakis (2, 4 tert di- butylphenyl.) -Bi - phenylene diphosphonite, which is commercially available as Irgaphos® ^® PEPQ Ciba Geigy AG.

If R-0 and R ^x -0- are divalent radicals, they are preferably derived from dihydric or trihydric alcohols.

R is preferably R ¹ and this is alkyl, aralkyl (preferably optionally substituted phenyl or phenylene), aryl (preferably optionally substituted phenyl) or a group of the formula α

wherein the cores A and B can carry further substituents and Y 'is an oxygen or sulfur bridge or a bridge member of the

Formula -CH (R ³ ) -,

R ^{2 is} hydrogen, Ci-Cg-alkyl or a group of the formula -COOR ³ and

R ^{3 is} C ₈ alkyl and n is 0 or 1 (referred to as divalent R ').

Particularly preferred radicals R are the radicals R ", where this -C ₂₂ alkyl, phenyl, the 1 to 3 substituents from the series cyano C ₂ alkyl, C ₂₂ alkoxy, benzyl, phenyl, 2, 2, 6th , 6-tetramethyl -pi - peridyl-4-, hydroxy, -CC _-8 alkylphenyl, carboxyl, -C (CH ₃ ) ₂ -C ₆ H ₅ , -COO -CC _-22 -alkyl, CH ₂ CH ₁₂ -COOH, -CH ₂ CH ₂ COO-, -Cι _-22 "alkyl or -CH ₂ -S-Cι- ₂₂ " alkyl can carry; or a group of formula i to vii. t .butyl

(i): Ü) (iii:

0 0

(iv) v

₃₃

(vi) (vii!

or two R "together form a group of the formula viii

mean where

R ^{8 is} hydrogen or C ₁ - ₂₂ alkyl,

R ⁵ is hydrogen, Cι- ₄ alkyl or -CO-Cι _-8 alkyl, R ^{4 is} hydrogen or C ₁ -2 ₂ alkyl,

R ^{5 is} hydrogen, Cχ- ₂₂ "alkyl, C ₁ - ₂₂ alkoxy, benzyl, cyano, phenyl, hydroxyl, Ci-g-alkylphenyl, Cχ- ₂₂ alkoxycarbonyl, Cι _{- 2} alkoxycarbonylethyl, carboxyethyl, 2, 2nd , 6, 6 - tetramethylpiperidyl -4 - or a group of the formula -CH ₂ -S-Cχ- ₂₂ alkyl or -C (CH ₃ ) ₂ -C ₆ H ₅ and

R ^{7 is} hydrogen, C ₁ - ₂ alkyl, hydroxy or alkoxy and

Y 'and n have the meanings given above.

Particularly preferred as radicals R are the radicals R ", which are one of the formulas a to g

(e) (f) (g)

correspond to what

_-8 alkylphenyl or phenyl -C-s-alkylphenyl or phenyl -Cι- ₄ alkyl R ⁹ are hydrogen, _-8 -alkyl, _-8 alkoxy, phenyl, Cι, R ¹⁰ and R ¹¹ independently of one another, hydrogen, Cι _-22 alkyl, phenyl or Cχ- ₈ alkylphenyl, R ¹² hydrogen or C _1-8 alkyl and R ¹³ cyano, carboxyl or Cι _-8 alkoxycarbonyl

mean. Among the groups of formula a are 2 - tert. -Butylphenyl, 2-phenylphenyl, 2- (1 ', 1' -dimethyl-propyl) -phenyl, 2 -cyclohexylphenyl, 2-tert. -Butyl -4 -methylphenyl, 2, 4 -Di - tert. -amylphenyl, 2,4-di- tert. -butylphenyl, 2, 4 -di-phenylphenyl, 2, 4 -di-tert. octylphenyl, 2-tert. -Butyl - -phenyl-phenyl, 2, 4-bis- (1 ', 1' -dimethylpropyl) -phenyl, 2- (1 '-phenyl-1' -methylethyl) -phenyl, 2, 4-bis- (1'-phenyl -1'-methylethyl) phenyl and 2, 4 -di-tert. -butyl-6-methylphenyl preferred.

Processes for the preparation of the phosphonites B) can be found in DE-A 40 01 397.

The polyester A) and the phosphorus-containing stabilizer are in amounts of

A) 40 to 99.9, preferably 50 to 95 and in particular 75 to 85% by weight with

B) 0.1 to 60, preferably 5 to 50 and in particular 15 to 25% by weight in the melt at temperatures from 230 to 290 ° C., preferably from 235 to 285 ° C. over a period of 0.1 to 30 minutes, preferably mixed from 0.2 to 25 minutes, discharged, cooled and granulated.

Suitable mixing units such as extruders, Banbury mixers and kneaders are known to the person skilled in the art, for which reason further details are unnecessary.

Another procedure for the preparation of component A is the mixing of stabilizer B) into a polyester prepolymer and subsequent post-condensation in the solid phase to the desired final viscosity number of polyester A).

In the process according to the invention, component A 'thus obtained is then mixed with a polycarbonate C) and, if appropriate, a polyester A) and a rubber-elastic polymer D) and, if appropriate, further additives E).

Mixing usually takes place in the form of granules of the individual components and subsequent homogenization in the melt or by any order of addition of components C) to E) to component A 'in the melt.

The temperatures are generally from 235 to 290 ° C., preferably from 240 to 285 ° C. and the residence times from 0.1 to 30, preferably from 0.2 to 15, minutes. A further addition of the polyester A) may be necessary to adjust the desired proportions of the polyester A) in the composition. Suitable polyesters A) are described above, it also being possible to use different polyesters A) for the production of component A 'and for the subsequent dilution. The mixing ratio is arbitrary.

According to the invention, the molding compositions comprise at least one polycarbonate as component C).

Halogen-free polycarbonates are preferably used as component C). Suitable halogen-free polycarbonates are, for example, those based on diphenols of the general formula

wherein Q is a single bond, a Ci to C ₈ -alkylene, C - to C ₃ -alkylidene, C ₃ - to C ₆ cycloalkylidene group, a C ₆ - to C ₁₂ arylene group and -O-, - S- or -S0 ₂ - means and m is an integer from 0 to 2.

The diphenols may also have substituents such as C until alkyl or C to C ₆ alkoxy in the phenylene radicals.

Preferred diphenols of the formula are, for example, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 1,1 - bis (4-hydroxyphenyl) cyclohexane. 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) cyclohexane, and 1,1-bis (4-hydroxyphenyl) -3, 3, 5- are particularly preferred. trimethylcyclohexane.

Both homopolycarbonates and copolycarbonates are suitable as component B; in addition to the bisphenol A homopolymer, the copolycarbonates of bisphenol A are preferred.

The suitable polycarbonates can be branched in a known manner, preferably by incorporating 0.05 to 2.0 mol%, based on the sum of the diphenols used, of at least trifunctional compounds, for example those having three or more than three phenolic compounds OH groups. Polycarbonates which have relative viscosities η _re χ of 1.10 to 1.50, in particular of 1.25 to 1.40, have proven particularly suitable. This corresponds to average molecular weights M _w (weight average) of 10,000 to 200,000, preferably 20,000 to 80,000.

The diphenols of the general formula are known per se or can be prepared by known processes.

The polycarbonates can be produced, for example, by

The diphenols are reacted with phosgene using the phase interface method or with phosgene using the homogeneous phase method (the so-called pyridine method), the molecular weight to be adjusted in each case being achieved in a known manner by a corresponding amount of known chain terminators. (Regarding polydiorganosiloxane-containing polycarbonates, see for example DE-OS 33 34 782).

Suitable chain terminators are, for example, phenol, pt-butylphenol but also long-chain alkylphenols such as 4- (1,3-tetramethylbutyl) phenol, according to DE-OS 28 42 005 or monoalkylphenols or dialkylphenols with a total of 8 to 20 carbon atoms in the alkyl substituents according to DE-A 35 06 472, such as p-nonylphenyl, 3,5-di-t-butylphenol, p-t-octylphenol, p-dodecylphenol, 2 - (3, 5-dimethyl-hep- tyl) phenol and 4 - (3, 5-dimethylheptyl) phenol.

Halogen-free polycarbonates in the sense of the present invention means that the polycarbonates are composed of halogen-free diphenols, halogen-free chain terminators and optionally halogen-free branching agents, the content of minor ppm amounts of saponifiable chlorine resulting, for example, from the production of the polycarbonates with phosgene by the phase interface process. is not to be regarded as containing halogen in the sense of the invention. Such polycarbonates with ppm contents of saponifiable chlorine are halogen-free polycarbonates in the sense of the present invention.

Amorphous polyester carbonates may be mentioned as further suitable components C), with phosgene being replaced by aromatic dicarboxylic acid units such as isophthalic acid and / or terephthalic acid units during production. For further details, reference is made to WO 82/02401.

Bisphenol A can also be replaced by Bisphenol TMC. Such polycarbonates are available under the trademark APEC HT ^® from Bayer. The rubber-elastic polymers contain (as component D) (often also referred to as impact modifiers, elastomers or rubbers).

In general, these are copolymers which are preferably composed of at least two of the following monomers: ethylene, propylene, butadiene, isobutene, isoprene, chloroprene, vinyl acetate, styrene, acrylonitrile and acrylic or methacrylic acid esters with 1 to 18 C - Atoms in the alcohol component.

Such polymers are e.g. in Houben-Weyl, Methods of Organic Chemistry, Vol. 14/1 (Georg-Thieme -Verlag, Stuttgart, 1961). Pages 392 to 406 and in the monograph by C.B. Bucknall, "Toughened Plastics" (Applied Science Publishers, London, 1977).

Some preferred types of such elastomers are presented below.

Preferred types of such elastomers are the so-called ethylene-propylene (EPM) or ethylene-propylene-diene (EPDM) rubbers.

EPM rubbers generally have practically no more double bonds, while EPDM rubbers can have 1 to 20 double bonds / 100 carbon atoms.

Examples of diene monomers for EPDM rubber are conjugated dienes such as isoprene and butadiene, non-conjugated dienes with 5 to 25 carbon atoms such as penta-1, 4-diene, hexa-1, 4-diene, hexa- 1,5-diene, 2,5-dimethylhexa-1,5-diene and octa-1,4-diene, cyclic see dienes such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene as well as alkenylnorbornenes such as 5-ethylidene-2-norbornene , 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and tricyclodienes such as 3-methyl-tri-cyclo (5.2.1.0.2.6) -3, 8-decadiene or their mixtures called. Hexa-1,5-diene, 5-ethylidene norbornene and dicyclopentadiene are preferred. The diene content of the EPDM rubbers is preferably 0.5 to 50, in particular 1 to 8,% by weight, based on the total weight of the rubber.

Polyolefin copolymers which can be obtained by polymerization in the presence of a metallocene catalyst are also suitable. Particularly preferred elastomers D) are polyethylene octene and polyethylene butene copolymers with a proportion of up to 50% by weight, preferably up to 45% by weight, of octene and / or butene.

EPM or EPDM rubbers can preferably also be grafted with reactive carboxylic acids or their derivatives. Here are e.g. Acrylic acid, methacrylic acid and their derivatives, e.g. Glycidyl (meth) acrylate, as well as maleic anhydride.

Another group of preferred rubbers are copolymers of ethylene with acrylic acid and / or methacrylic acid and / or the esters of these acids. In addition, the rubbers can also contain dicarboxylic acids such as maleic acid and fumaric acid or derivatives of these acids, e.g. Contain esters and anhydrides, and / or monomers containing epoxy groups. These dicarboxylic acid derivatives or monomers containing epoxy groups are preferably incorporated into the rubber by adding monomers of the general formulas I or II or III or IV containing dicarboxylic acid or epoxy groups to the monomer mixture

R ¹ C (COOR ² ) = C (COOR ³ ) R ⁴ (I)

Rl R ⁴

(II)

CO CO

0

/ \

CHR ⁷ = CH (CH ₂ : (CHR ⁶ ) _σ CH CHR ⁵ (Uli

CH ₂ = CR ⁹ COO (CH ₂ ) _p CH CHR ⁸ (IV)

\ /

0

where R ¹ to R ^{9 represent} hydrogen or alkyl groups having 1 to 6 carbon atoms and m is an integer from 0 to 20, g is an integer from 0 to 10 and p is an integer from 0 to 5. The radicals R ¹ to R ^{9 are} preferably hydrogen, where m is 0 or 1 and g is 1. The corresponding compounds are maleic acid, fumaric acid, maleic anhydride, allyl glycidyl ether and vinyl glycidyl ether.

Preferred compounds of the formulas I, II and IV are maleic acid, maleic anhydride and epoxy group-containing esters of acrylic acid and / or methacrylic acid, such as glycidyl acrylate, glycidyl methacrylate and the esters with tertiary alcohols, such as t-butyl acrylate. Although the latter have no free carboxyl groups, their behavior comes close to that of the free acids and is therefore referred to as monomers with latent carboxyl groups.

The copolymers advantageously consist of 50 to 98% by weight of ethylene, 0.1 to 20% by weight of monomers containing epoxy groups and / or monomers containing methacrylic acid and / or monomers containing acid anhydride groups and the remaining amount of (meth) acrylic acid esters.

Copolymers of are particularly preferred

50 to 98.9, in particular 55 to 95% by weight of ethylene,

0.1 to 40, in particular 0.3 to 20% by weight of glycidyl acrylate and / or glycidyl methacrylate, (meth) acrylic acid and / or

Maleic anhydride, and

1 to 45, in particular 10 to 40% by weight of n-butyl acrylate and / or 2-ethylhexyl acrylate.

Further preferred esters of acrylic and / or methacrylic acid are the methyl, ethyl, propyl and i- or t-butyl esters.

In addition, vinyl esters and vinyl ethers can also be used as comonomers.

The ethylene copolymers described above can be prepared by processes known per se, preferably by random copolymerization under high pressure and elevated temperature. Appropriate methods are generally known.

Preferred elastomers are also emulsion polymers, the production of which is described, for example, by Blackley in the monograph "Emulsion Polymerization". The emulsifiers and catalysts that can be used are known per se. In principle, homogeneous elastomers or those with a shell structure can be used. The shell-like structure is determined by the order of addition of the individual monomers; the morphology of the polymers is also influenced by this sequence of pulls.

Representative here are as monomers for the production of the rubber part of the elastomers acrylates such as n-Butyl acrylate and 2-ethylhexyl acrylate, corresponding methacrylates, butadiene and isoprene and mixtures thereof. These monomers can be combined with other monomers such as e.g. Styrene, acrylonitrile, vinyl ethers and other acrylates or methacrylates such as methyl methacrylate, methyl acrylate, ethyl acrylate and propyl acrylate can be copolymerized.

The soft or rubber phase (with a glass transition temperature below 0 ° C) of the elastomers can be the core, the outer shell or a middle shell (in the case of elastomers with more than two layers). in the case of multi-layer elastomers, several shells can also consist of a rubber phase.

If, in addition to the rubber phase, one or more hard components (with glass transition temperatures of more than 20 ° C.) are involved in the construction of the elastomer, these are generally polymerized by styrene, acrylonitrile, methacrylonitrile, α-methylstyrene, p-methylstyrene, acrylic acid esters and methacrylic acid esters such as methyl acrylate, ethyl acrylate and methyl methacrylate as main monomers. In addition, smaller proportions of further comonomers can also be used here.

In some cases it has proven to be advantageous to use emulsion polymers which have reactive groups on the surface. Such groups are e.g. Epoxy, carboxyl, latent carboxyl, amino or amide groups, as well as functional groups, by using monomers of the general formula

Rio _R n

CH ₂ = C— x— —C— Ri

0 can be introduced

where the substituents can have the following meanings: R ^{10 is} hydrogen or a C 1 -C ₄ -alkyl group,

R ^{11 is} hydrogen, a C 1 -C ₈ -alkyl group or an aryl group, in particular phenyl,

R ^{12 is} hydrogen, a C 1 -C ₁ -alkyl group, a C ₆ - C ₁ -C ₂ aryl group or -OR ¹³

R ^{13 is} a C 1 to C ₈ alkyl or Cζ to C ₂ aryl group, which can optionally be substituted with 0 or N-containing groups,

X is a chemical bond, a C ~ to C ~ alkylene or C ₆ - Ci ₂ ~ arylene group or O

C Y

Y O-Z or NH-Z and

Z is a Ci to Cι ₀ alkylene or C ₆ - to Cχ ₂ arylene group.

The graft monomers described in EP-A 208 187 are also suitable for introducing reactive groups on the surface.

Further examples include acrylamide, methacrylamide and substituted esters of acrylic acid or methacrylic acid such as (Nt-butylamino) ethyl methacrylate, (N, N-dimethylamino) ethyl acrylate, (N, N-dimethylamino) methyl acrylate and (N, N-diethylamino) called ethyl acrylate.

The particles of the rubber phase can also be crosslinked. Monomers acting as crosslinkers are, for example, buta-1,3-diene, divinylbenzene, diallyl phthalate and dihydrodicyclopentadienyl acrylate, and the compounds described in EP-A 50 265.

So-called graft-linking monomers can also be used, i.e. Monomers with two or more polymerizable double bonds, which react at different rates during the polymerization. Compounds are preferably used in which at least one reactive group polymerizes at approximately the same rate as the other monomers, while the other reactive group (or reactive groups) e.g. polymerized much slower

(polymerize). The different polymerization rates result in a certain proportion of unsaturated dop- 18 fur bonds in rubber with it. If a further phase is subsequently grafted onto such a rubber, the double bonds present in the rubber react at least partially with the graft monomers to form chemical bonds, ie the grafted phase is at least partially linked to the graft base via chemical bonds.

Examples of such graft-crosslinking monomers are monomers containing allyl groups, in particular allyl esters of ethylenically unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate,

Diallyl maleate, diallyl fumarate, diallyl itaconate or the corresponding monoallyl compounds of these dicarboxylic acids. There are also a large number of other suitable graft-crosslinking monomers; for further details, reference is made to, for example, US Pat. No. 4,148,846.

In general, the proportion of these crosslinking monomers in the impact-modifying polymer is up to 5% by weight, preferably not more than 3% by weight, based on the impact-modifying polymer.

Some preferred emulsion polymers are listed below. First of all, graft polymers with a core and at least one outer shell are to be mentioned, which have the following structure:

Instead of graft polymers with a multi-layer structure, it is also possible to use homogeneous, ie single-layer elastomers composed of buta-1,3-diene, isoprene and n-butyl acrylate or their copolymers. These products can also be prepared by using crosslinking monomers or monomers with reactive groups.

Examples of preferred emulsion polymers are n-butyl acrylate / (meth) acrylic acid copolymers, n-butyl acrylate / glycidyl acrylate or n-butyl acrylate / glycidyl methacrylate copolymers, graft polymers with an inner core of n-butyl acrylate or based on a butadiene and an outer shell from the above mentioned copolymers and copolymers of ethylene with comonomers which provide reactive groups.

The elastomers described can also be made by other conventional methods, e.g. by suspension polymerization.

Silicone rubbers as described in DE-A 37 25 576, EP-A 235 690, DE-A 38 00 603 and EP-A 319 290 are also preferred.

Of course, mixtures of the rubber types listed above can also be used.

In addition to the essential components A), B), C) and D), further additives E) can be added to the molding compositions.

Fibrous or particulate fillers are carbon fibers, glass fibers, glass spheres, amorphous silica, asbestos, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, barium sulfate and feldspar, which are present in quantities of up to 50% by weight. , in particular up to 40%.

Carbon fibers, aramid fibers and potassium titanate fibers may be mentioned as preferred fibrous fillers, with glass fibers being particularly preferred as E-glass. These can be used as rovings or cut glass in the commercially available forms.

The fibrous fillers can be surface-pretreated with a silane compound for better compatibility with the thermoplastic. Suitable silane compounds are those of the general formula

(X- (CH ₂ ) _n ) k "Si (0-C _m H _{2m +} ι) _4-k

in which the substituents have the following meaning:

n is an integer from 2 to 10, preferably 3 to 4 m is an integer from 1 to 5, preferably 1 to 2 k is an integer from 1 to 3, preferably 1

Preferred silane compounds are aminopropyltrimethoxysilane,

Aminobutyltrimethoxysilane, aminopropyltriethoxysilane, aminobutyltriethoxysilane and the corresponding silanes which contain a glycidyl group as substituent X.

The silane compounds are generally used in amounts of 0.05 to 5, preferably 0.5 to 1.5 and in particular 0.8 to 1% by weight (based on E) for surface coating.

Acicular mineral fillers are also suitable.

For the purposes of the invention, acicular mineral fillers are understood to be mineral fillers with a pronounced acicular character. An example is needle-shaped wollastonite. The mineral preferably has an L / D (length diameter) ratio of 3: 1 to 35: 1, preferably 8: 1 to 11: 1. The mineral filler can optionally have been pretreated with the abovementioned silane compounds; however, pretreatment is not essential.

Kaolin, calcined kaolin, wollastonite, talc and chalk may be mentioned as further fillers.

As component E), the thermoplastic molding compositions according to the invention can contain customary processing aids such as stabilizers, oxidation retarders, agents against heat decomposition and decomposition by ultraviolet light, lubricants and mold release agents, colorants such as dyes and pigments, nucleating agents, plasticizers, etc. Examples of oxidation retarders and heat stabilizers are sterically hindered phenols and / or phosphites, hydroquinones, aromatic secondary amines such as diphenylamines, various substituted representatives of these groups and their mixtures in concentrations of up to 1% by weight, based on the weight of the thermoplastic molding compositions called, which are different from B).

Various substituted resorcinols, salicylates, benzotriazoles and benzophenones may be mentioned as UV stabilizers, which are generally used in amounts of up to 2% by weight, based on the molding composition.

Inorganic pigments such as titanium dioxide, ultramarine blue, iron oxide and carbon black, organic pigments such as phthalocyanines, quinacridones, perylenes and dyes such as nigrosine and anthraquinones can also be added as colorants.

Sodium phenylphosphinate, aluminum oxide, silicon dioxide and preferably talc are used as nucleating agents.

Lubricants and mold release agents are usually used in amounts of up to 1% by weight. Long-chain fatty acids (e.g. stearic acid or behenic acid), their salts (e.g. Ca or Zn stearate) or montan waxes (mixtures of straight-chain, saturated carboxylic acids with chain lengths of 28 to 32 carbon atoms) as well as low molecular weight polyethylene or polypropylene waxes are preferred.

Examples of plasticizers are dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils, N- (n-butyl) benzenesulfonamide.

The molding compositions may also contain 0 to 2% by weight of fluorine-containing ethylene polymers. These are polymers of ethylene with a fluorine content of 55 to 76% by weight, preferably 70 to 76% by weight.

Examples of these are polytetrafluoroethylene (PTFE), tetrafluorethylene-hexafluoropropylene copolymers or tetrafluoroethylene copolymers with smaller proportions (generally up to 50% by weight) of copolymerizable ethylenically unsaturated monomers. These are described, for example, by Schildknecht in "Vinyl and Related Polymers", Wiley-Verlag, 1952, pages 484 to 494 and by Wall in "Fluorpolymers" (Wiley Interscience, 1972). These fluorine-containing ethylene polymers are homogeneously distributed in the molding compositions and preferably have a particle size dso (number average) in the range from 0.05 to 10 μm, in particular from 0.1 to 5 μm. These small particle sizes can be achieved particularly preferably by using aqueous dispersions of fluorine-containing ethylene polymers and incorporating them into a polyester melt.

After the production of component A '), the thermoplastic molding compositions according to the invention can be produced by processes known per se, in which the starting components are mixed in conventional mixing devices such as screw extruders, Brabender mills or Banbury mills and then extruded. After the extrusion, the extrudate can be cooled and crushed. Individual components can also be premixed and the remaining starting materials added individually and / or likewise mixed. The mixing temperatures are usually 230 to 290 ° C.

The method according to the invention leads to more stable blend compositions during processing. Molding compositions obtainable by the process can be processed stably at high temperatures, the moldings having a perfect surface and good mechanical properties.

Preferred molding compositions included

A) 1 to 97.9; preferably 5 to 91.8 and in particular 7 to 89.5% by weight

B) 0.1 to 5, preferably 0.2 to 2.5 and in particular 0.5 to 1.5% by weight

C) 1 to 97.9, preferably 5 to 91.8 and in particular 7 to 89.5% by weight

D) 1 to 50, preferably 3 to 40% by weight

E) 0 to 50, preferably 0 to 30% by weight,

the sum of the percentages by weight A) to E) being 100%.

Examples of uses of the moldings are household articles, automotive applications, electronic components and medical-technical devices. 23

Examples

Component A) polybutylene terephthalate with a viscosity number of 130 ml / g and a carboxyl end group content of 34 meq / kg (Ultradur® B 4500 from BASF AG) (VZ measured in 0.5% by weight solution of phenol / o-dichlorobenzene), l: l mixture at 25 ° C, according to ISO 1628

Component B) Irgafos ^® PEPQ (tetrakis (2,4-di-tert.butylphenyl) -4,4'-diphenylene-diphosphonite)

Component A ') 80% by weight of component A) above with 20% by weight of component B) above

were melt mixed on a twin-screw extruder at 250 ° C, discharged, cooled and granulated.

Component C) polycarbonate with a VZ of 61 ml / g, (based on bisphenol -A) measured in phenol / dichloromethane

(1: 1) (Lexan ^® 161 from General Electric Plastics).

Component D) methyl methacrylate / butadiene / styrene graft rubber with a three-shell structure (polybutadiene core, polystyrene shell, PMMA shell), consisting of 15.6% by weight of methyl methacrylate, 16.7% by weight of styrene and 67.7 % By weight of butadiene.

For the comparative experiments, components A) to D) were mixed in a twin-screw extruder at 250 to 260 ° C. and extruded in a water bath. After granulation and drying, test specimens were injected and tested on an injection molding machine at 260 ° C.

The procedure according to the invention was as described above, but component A 'was used.

The heat resistance was determined according to HDT B (ISO 75-2). The notched impact strength of the products was determined according to ISO bars ISO 179 leA.

The damage work of the molding compositions was measured according to DIN 53 433 at -30 ° C.

The processing stability was determined by two methods: 24 a) The melt viscosity in the capillary rartometer (290 ° C, 150 Hz) was measured over a period of 20 minutes and the drop (in%) was determined.

b) Plates were made at 290 ° C. After that the

Damage work determined at -30 ° C. Furthermore, the surfaces (streaks, discoloration) of the panels were visually inspected and classified into classes 1 (very good) to 5 (poor).

The compositions of the molding compositions and the results of the tests are shown in the table.

Table:

Claims

claims

1. A process for the preparation of stabilized polyester / polycarbonate blends, characterized in that

A) 40 to 99.9% by weight of a polyester and

B) 0.1 to 60% by weight of a phosphorus-containing stabilizer

Process according to Claim 1, characterized in that the polyester A) used is a polyalkylene terephthalate which has 2 to 10 carbon atoms in the alcohol part.

3. Process according to claims 1 or 2, characterized in that an organic phosphorus-containing stabilizer is used as component B).

Process according to claims 1 or 3, characterized in that a phosphonite of the general formula I is used

in which

m 0 or 1, n 0 or 1, y is an oxygen, sulfur or 1, 4-phenylene bridge or a bridge member of the formula -CH (R ² ) - all R-0- and R ⁱ -O- groups independently one another, the remainder of an aliphatic, alicyclic or aromatic alcohol, which can contain up to three hydroxyl groups, but the hydroxyl groups are not arranged such that they can be part of a phosphorus-containing ring (referred to as monovalent RO groups), or two R-0 or R ¹ -0 groups bonded to a phosphorus atom, each independently of one another together the remainder of an aliphatic, alicyclic or aromatic alcohol with a total of up to three hydroxyl groups (as bivalent R-0- or R ¹ denotes 0 groups),

R ^{2 is} hydrogen, -CC _a -alkyl or a group of the formula COOR ³ and

R ^{3 is} Ci- ₈ alkyl.

5. Process according to claims 1 to 4, characterized in that tetrakis (2, 4-di-tert-butylphenyl) biphenylene diphosphonite is used as the phosphonite.

6. The method according to claims 1 to 5, characterized in that one

A) 50 to 95 wt .-% of a polyester and

B) 5 to 50 wt .-% of a phosphorus-containing stabilizer

used to produce component A '.