EP0960165A1

EP0960165A1 - Thermostable styrene copolymer

Info

Publication number: EP0960165A1
Application number: EP98908053A
Authority: EP
Inventors: Michael Schneider; Michael Fischer; Hermann Gausepohl
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1997-02-15
Filing date: 1998-02-04
Publication date: 1999-12-01
Also published as: DE19705828A1; WO1998036026A1; AU6619998A

Abstract

The invention relates to a mixture containing 50-90 wt. % of a styrene-diphenyl ethylene copolymer obtained by anionic block (co) polymerization of styrene and 1,1-diphenyl-ethylene or a block copolymer (A) and 10-50 wt. % of a particle-shaped graft copolymer (B) with a transition temperature (Tg) of less than -10 DEG C and at least 3, preferably 4 layers or shells whereby at least one shell or the graft nucleus (B1) has a transition temperature (Tg) of more than 25 DEG C and at least one shell or graft nucleus has a transition temperature (Tg) of less than 25 DEG C, preferably below O DEG C wherein any spatial sequence of the graft shells is possible.

Description

Heat-resistant styrene copolymer

description

The invention relates to a heat-resistant, impact-modified thermoplastic molding composition with a softening point above 100 ° C. based on a copolymer of styrene and 1,1-diphenylethylene (A) and a rubber-elastic particulate graft copolymer (B).

Polystyrene molding compositions with a heat distortion temperature above 100 ° C (expressed, for example, by the softening temperature according to Vicat) have hitherto been obtained either by copolymerizing styrene with α-methylstyrene, maleic anhydride, maleic acid-N-aryl / alkylimide, (meth) acrylic acid amide or by mixing with a correspondingly higher softening, polystyrene-compatible polymer such as polycarbonate or polyphenylene ether. The impact strength is achieved by admixing rubber-elastic particulate graft copolymers.

From GB-A-1 354 289 e.g. Copolymers of styrene, acrylonitrile and N-phenyl or N-cycloalkyl-acrylamide are known which are said to have increased heat resistance. However, the special acrylamide monomers required are difficult to access and therefore expensive.

The copolymerization of styrene and e.g. For kinetic reasons, maleic anhydride does not lead directly to statistical copolymers (SMA), so that their technical production is difficult. SMA copolymers as well as styrene / α-methylstyrene copolymers are characterized by an increased heat resistance, which is, however, not sufficient for many applications, especially since the proportion of these comonomers cannot be increased arbitrarily, since otherwise an incompatibility with other components, especially the usual graft rubbers.

Mixtures of styrene polymers with other polymers often show signs of segregation during processing, which, for example in the case of injection molding compounds, are manifested by low weld line strength and can considerably reduce the mechanical properties of the moldings. Mixtures of ABS or ASA graft rubbers with polycarbonate do have a significantly higher heat resistance than ABS or ASA resins; however, this is for some applications in which particularly high heat resistance is required, such as in hairdryer housings, in the electronics industry. strie, or insufficient in the engine area. The heat resistance can be increased by polycarbonate contents of more than 50%, but processing is made more difficult by poor flow behavior, so that large molded parts often have poor quality in injection molding. This also applies to mixtures with polycarbonate, in which the graft rubber in the graft slurry as well as the matrix material contains α-methylstyrene.

Styrene copolymers with t-butylstyrene or p-methylstyrene have only a minor effect on the heat resistance and have therefore not been able to be introduced.

German patent application 44 36 499 describes anionically produced copolymers of styrene and 1,1-diphenylethylene which are characterized by a very high heat resistance, expressed by a high softening temperature, but have only a low toughness. These copolymers can also be impact modified,

It was therefore the task of proposing molding compositions based on copolymers of styrene and 1,1 diphenylethylene (DPE) which are more heat-resistant than styrene homopolymers, which have good melt flowability, in order to be able to produce even complicated injection molded parts and with conventional graft rubbers can be modified impact-resistant.

The immediate subject of the invention is a mixture which can be used as a molding composition and which, based on the sum of A and B, contains:

A: 50 to 90% by weight of at least one hard polymer A with a glass transition temperature T _g of above 25 ° C. selected from copolymers AI of 50 to 99 mol% of polymerized units of styrene and 1 to 50 mol% of polymerized units of 1 , 1-diphenylethylene and / or block copolymers A2 which have at least one polystyrene block and at least one poly (styrene / diphenylethylene) block of the above composition, as obtained by anionic block (co) polymerization of styrene or styrene and 1, 1 -Diphenylethylene can be obtained;

B: 10 to 50% by weight of a particulate graft copolymer B with at least one glass transition temperature T _g of below -10 ° C., based on the sum of B1 to B3 or, if appropriate, B1 to B4: Bl: 0 to 90% by weight of a first graft core Bl with a glass transition temperature T _g of more than 25 ° C., based on the sum of B1 to B14;

B1: 50 to 99.8% by weight of units polymerized in at least one vinylaromatic monomer B1;

B12: 0.1 to 20% by weight of polymerized units of at least one crosslinking and possibly graft-active bifunctional or multifunctional monomer B12 with two or more functional groups of different reactivity;

B13: 0.1 to 20% by weight of polymerized units of at least one at least two or more functional, crosslinking monomer B13 with functional groups of the same reactivity; such as

B14: 0 to 50% by weight of one or more copolymerisable

Monomer;

B2: 5 to 90% by weight of a first graft shell B2 or one

Graft core with a freezing temperature T _g of below 0 ° C, based on the sum of B21 to B24:

B21: 50 to 99.9% by weight of at least one alkyl acrylate, siloxane, diene or EPDM rubber;

B22: 0.1 to 20% by weight of at least one polyfunctional, crosslinking and / or graft-active monomer B22 with two or more functional groups of different reactivity, which can at the same time have crosslinking and graft-active action;

B23: 0 to 50% by weight of one or more monomers B23 copolymerizable with B21 and B22;

B3: 5 to 90% by weight of a (possibly second) graft shell B3 with a glass transition temperature T _g of more than 25 ° C., based on the sum of B31 to B34:

B31: 5 to 100% of at least one vinyl aromatic monomer;

B32: 0 to 20% of at least one polyfunctional, crosslinking and / or graft-active monomer B32 with two or more functional groups of different reactivity, which can simultaneously have crosslinking and graft-active action; B33: 0 to 95% cyclohexyl methacrylate;

B34: 0 to 95% of one or more copolymerizable unsaturated monomers B34;

B4: 0 to 50% by weight of at least one further graft shell B4 different from B2 and / or B3 with a freezing temperature T _g of more than 25 ° C., the spatial sequence of the graft shells B2, B3 and optionally B4 being arbitrary with the Provided that at least one of the graft shells B2 and B3 is arranged between the graft core B1 and the graft sheath B4.

Mixtures in which the spatial sequence of the constituents B1, B2, B3 and, if appropriate, B4 is arbitrary can also be regarded in general as long as only either the graft core or at least one graft shell has a freezing temperature T _g of below 25 ° C. and either the graft core or at least one graft shell have a freezing temperature T _g of over 25 ° C. The order of the components is therefore irrelevant.

Component A

As component A, a mixture is preferably used both from a copolymer Al of 50 to 99 mol% of polymerized units of styrene and from 1 to 50 mol% of polymerized units of 1,1-diphenylethylene and also a block copolymer A2 which contains at least one polystyrene block and has at least one poly (styrene / diphenylethylene) block of the above composition, the idea being that block copolymer A2 improves the binding of copolymer AI to component B.

Suitable copolymers A are the copolymers described in DE-A-44 36 499 (referred to herein as AI) which are either copolymerized from 50 to 99 mol% of styrene units and from 1 to 50 mol% of units of 1,1 Diphenylethylene can be constructed as they are obtained by anionic copolymerization of styrene and DPE or two or three block copolymers from PS and P (S-co-DPE) segments or statistical copolymers P (S-co-DPE), below denoted by A2, and mixtures of AI and A2.

Generally speaking, the particulate graft rubber B consists of a core of polymers which either have rubber-elastic properties at the intended use temperature of the molding compositions (for example at -20 to + 120 ° C.), that is to say a glass covering has a transition temperature T _g below 0, preferably below -20 ° C and a single or multi-layer shell grafted thereon, at least one of which, preferably the outer one, consists of polymers which have a glass transition temperature T _g above 25 ° C, preferably above 100 ° C. Or you choose a core made of polymers that have rigid, non-rubber-elastic properties at the intended use temperature. In this case, at least one, preferably not the outer shell, is made of rubber-elastic polymers, which therefore have a glass transition temperature below 0, preferably below -20 ° C.

The proportion of hard component A, based on the sum of A and B, is preferably 30 to 70 and particularly preferably 40 to 60% by weight. The proportion of particulate graft rubber B is accordingly 30 to 70 or 40 to 60% by weight.

If the thermoplastic molding compositions according to the invention contain a mixture of AI and A2 for the hard component A, the proportion of A2, based on AI + A2, can be arbitrary, i.e. between 0 and 100 (preferably 5 to 50 and in particular 5 to 15)% by weight.

AI

The copolymers AI described in DE-A-44 36 499 from 50 to 99 mol% of copolymerized styrene units and 1 to 50 mol% of polymerized units of 1,1-diphenylethylene can be obtained by anionic copolymerization of styrene and DPE.

For the polymerization process, the usual precautions that anionic copolymerization requires, i.e. absolute exclusion of water, oxygen and polar, in particular water-like substances, such as alcohols, carboxylic acids and generally substances with mobile hydrogen atoms.

Instead of 1,1-diphenylethylene, derivatives thereof which may be substituted on the aromatic rings with alkyl groups having up to 22 carbon atoms can be used. Preferred alkyl groups have 1 to 4 carbon atoms. However, the unsubstituted 1,1-diphenylethylene itself is particularly preferably used.

Instead of styrene, its derivatives substituted in the α-position or on the aromatic ring with alkyl groups having 1 to 4 carbon atoms can be used. It is preferred to use α-methylstyrene and particularly preferably unsubstituted styrene itself. The molar ratio of the DPE units to styrene units is generally in the range from 1: 1 to 1:25, preferably in the range from 1: 1.05 to 1:15 and particularly preferably in the range from 1: 1.1 to 1 : 10. Since diphenylethylene does not polymerize on its own with the technically customary processes, products with molar

Ratios of more than 1: 1 are not easily accessible.

The anionic polymerization is carried out in a customary manner in a chemically inert solvent. In general, aliphatic and aromatic hydrocarbons are suitable. Suitable solvents are, for example, cyclohexane, methylcyclohexane, benzene, toluene, ethylbenzene or xylene.

It is also possible to use hydrocarbons in which the copolymer formed during the reaction is not soluble. In this case, precipitation polymerization takes place or, if a dispersing aid is used, dispersion polymerization takes place. Examples of suitable solvents for such a process are butane, pentane, n-hexane, isopentane, heptane, octane and isooctane.

The polymerization is generally initiated by an alkali metal compound, especially lithium. Examples of initiators are methyl lithium, ethyl lithium, propyllithium, n-butyllithium, sec. Butyllithium and tert-butyllithium. The organometallic compound is usually added as a solution in a chemically inert (inert) hydrocarbon. The dosage depends on the desired molecular weight of the polymer, but is generally in the range from 0.002 to 5 mol%, if it is based on the monomers.

Small amounts of a polar, aprotic solvent ("cosolvent") can be added to increase the rate of polymerization. Diethyl ether, for example, are suitable,

Diisopropyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether or in particular tetrahydrofuran. In this process variant, the cosolvent is generally added in a small amount of approximately 0.5-5% by volume, with THF being particularly preferred in an amount of 0.1-0.3% by volume. The reaction parameters are adversely affected in pure THF.

The polymerization temperature can be between about 0 and 130 ° C. Temperatures of 50 to 90 ° C. are preferred. In general, polymerization is carried out under isothermal conditions, ie with the polymerization temperature kept constant. But you can also let the temperature rise, for example starting at 30 and ending at 120 ° C, so that the heat of reaction does not have to be removed directly from the reactor, but first in a downstream cooler. It is particularly expedient first to polymerize isothermally and to allow the temperature to rise adiabatically towards the end of the polymerization, ie at low monomer concentrations, in order to keep the polymerization times short.

A2

Component A2 is block copolymers with blocks of, for example, the general structures (ab) _n , aba, bab, X [(ab) _n ] _m , X [(ba) _n ] _m , X [(aba)] _m and X [bab] _m , where a for a block of a copolymer of the monomers styrene and DPE, b for a styrene block, X for the rest of an m-functional coupling agent, n for an integer in the range from, for example, 1 to 5 and m stand for an integer in the range of, for example, 2 to 20.

After the polymerization, the coupling agent X reacts with the living anionic chain ends, as a result of which the structures described above are formed. Examples of suitable coupling agents can be found in US Pat. Nos. 3,985,830, 3,280,084, 3,637,554 and 4,091,053. Examples include epoxidized glycerides such as epoxidized linseed oil or soybean oil; divinylbenzene is also suitable. If the living anionic end is on the side of the b block, then it is preferably coupled with compounds which contain epoxy and / or ester groups; however, if the a block forms the active end, divinylbenzene is preferably used for the coupling.

The block transitions can be sharply separated or smeared. A smeared transition is understood as a chain piece of the molecule in which the monomer composition of block a changes to that of block b more or less statistically. The desired molecular weight of the blocks is adjusted via the ratio of initiator to monomer.

A2 can be used on its own; for economic reasons, however, a mixture with AI is preferable. AI can also be used on its own; For technical reasons, however, a mixture with A2 is preferable, since A2, as mentioned, can serve to impart compatibility with the graft shell of the particulate graft rubber B.

The styrene content in the poly (S-co-DPE) block of A2 should expediently be similar to or match the styrene content in AI in order to achieve good compatibility and phase connection. Specifically, the graft rubber B consists of, for example

either a rubber-like graft core with a glass transition temperature T _g below 0 ° C., preferably made of a polyalkyl acrylate with an alcohol having at least 4 carbon atoms (in particular poly-n-BA) or a polydiene and a shell made of a (co) polymer with a glass transition temperature T _g above 25 ° C which is compatible with the DPE copolymer A, preferably PS or polycyclohexyl methacrylate;

or off

a hard graft core made of a material with a glass transition temperature T _g above 0 ° C, preferably polystyrene; a first (inner) shell made of a rubber-like material with a glass transition temperature T _g below 0 ° C., preferably a polyalkyl acrylate with an alcohol having at least 4 carbon atoms; and an outer shell made of a (co) polymer that is compatible with the DPE-containing copolymer, preferably PS or polycyclohexyl methacrylate.

Graft base Bl

According to the invention, the particulate graft copolymer obtained by multi-stage emulsion polymerization consists either of a graft base (graft core) B1, a first graft shell B2 (which can also be understood as a graft core B2 if it is not preceded by a graft base B1) and one or more graft shells B3 and possibly B4.

The graft base B1 can therefore be missing or it makes up 0-90 (usually 5-90; in particular 5-50)% by weight of the particulate graft copolymer.

The graft base B1 is particularly preferably present in a proportion of 5 to 25% by weight in the graft copolymers according to the invention.

The graft base B1 consists of a material which has a glass transition temperature of at least 0 ° C., preferably at least 50 ° C., in particular from 80 to 130 ° C.

The graft round layer B1 is composed of the monomers B1 and optionally B12 to B14. B1 is used in a proportion of 50 to 99.8% by weight, preferably 60 to 99% by weight, particularly preferably 60 to 98% by weight, based on the sum of B1 to B14, and consists of at least a vinyl aromatic Monomers. Examples of vinyl aromatic monomers are styrene, α-methylstyrene or alkylated styrenes such as p-methylstyrene or pt-butylstyrene. Styrene, α-methylstyrene or p-methylstyrene or mixtures thereof are particularly preferably used. Styrene is very particularly preferably used.

In addition to the monomers B1, component B1 can also contain monomers B12 to B14 copolymerizable therewith. Examples of monomers B12 are acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl methacrylate, glycidyl methacrylate, phenoxyethyl acrylate, maleic anhydride or vinyl methyl ether. Mixtures of different B12 monomers can of course also be used. Preferred monomers B12 include acrylonitrile and methyl methacrylate. According to the invention, the proportion of the monomers B12 is from 0 to 50, preferably from 0 to 39% by weight, in particular from 0 to 30% by weight, based on the components B1 to B14.

The graft base also contains crosslinking monomers B13 and B14. B13 forms a proportion of 0.1 to 20, preferably 0.5 to 10, particularly preferably 1 to 5% by weight, based on the sum of B1 to B14. As the crosslinking monomer B13, dihydrodicyclopentadienyl acrylate B131 alone or in combination with at least one other crosslinker with two or more functional groups of different reactivity can contain B132. B13 accordingly consists of 0.1 to 100, preferably from 25 to 100% by weight, based on the sum of B131 and B132, of B131 and a complementary amount of B132. The crosslinking component particularly preferably contains from 50 to 100% by weight of B131 and from 0 to 50% by weight of B132.

Examples of suitable crosslinkers B132 are ethylenically unsaturated monomers which carry epoxy, hydroxyl, carboxyl, amino or acid anhydride groups. These include hydroxy-CIO alkylacrylates or hydroxy-CIO alkyl methacrylates, especially hydroxyethyl acrylate or hydroxy-n-propylacrylate. Allyl methacrylate, methallyl methacrylate, acryloylalkoxysilanes or methacryloylalkyloxysilanes are also suitable. For example, ß-methacryloyloxyethyl-dimethoxymethylsilane, γ-methacryloyloxy-n-propylmethoxy-dimethylsilane, γ-methacryloyl-oxy-n-propylmethoxymethylsilane, γ-methacryloyloxy-n-propyltrimethoxysilane, γ-methoxymiloxymiloxymyl methacrylate γ-methacryloyloxy-n-propyldiethoxy-methylsilane, δ-methacryloyloxy-n-butyldiethoxymethylsilane. The preferred mixtures of crosslinkers B131 and B132 include

Mixtures of dihydrodicyclopentadienyl acrylate and hydroxyethyl acrylate; Dihydrodicyclopentadienyl acrylate and allyl methacrylate;

Dihydrodicyclopentadienyl acrylate, hydroxyethyl acrylate and allyl methacrylate; Dihydrodicyclopentadienyl acrylate, allyl methacrylate and β-methacryloyl-oxyethyl-dimethoxymethylsilane; Dihydroxydicyclopentadienyl acrylate and ß-methacryloyl-oxyethyl-dimethoxymethyl-silane.

In addition, the graft base B1 is constructed according to the invention from 0.1 to 20, preferably from 0.5 to 10% by weight, based on the components B1 to B14, of at least one crosslinking agent with two or more functional groups of the same reactivity (B14) . Particularly preferred graft copolymers contain B14 in amounts of 1 to 5% by weight, based on the sum of B1 to B14. In principle, the B13 and B14 can be in any relation to each other. However, preferred graft bases B1 contain B13 and B14 in a ratio of 1: 0.75 to 1: 5. The proportion of B14 can, however, also be lower, for example up to 1: 0.5. Higher shares in B14 can also be considered. The ratios from B13 to B14 can be up to 1:10. The ratio of B13 to B14 is particularly preferably from 1: 0.8 to 1: 3, or 1: 1 to 1: 3, in particular from 1: 0.9 to 1: 2, for example 1: 1 or 1: 1, 5.

Suitable crosslinkers B14 are e.g. B. acrylates or methacrylates of polyhydric alcohols. Preferred are Monoalkylenglycoldi (meth) - acrylates, such as C ₂ _ ₄ -Alkylenglycoldiacrylate such as ethylene glycol diacrylate, n-propylene glycol, 1, 3-n-butylene glycol or 1, 4-n-butylene. In addition, tricarboxylic Tetraalkylenglykoldimethacrylate di- come into consideration, preferably C ₂ _ ₄ -Alkylenglykoldimethacrylate such as ethylene, n-propylene glycol, 1, 3-n-butylene glycol or 1, 4-n-butylene glycol dimethacrylate. Acrylates or methacrylates of glycerol, trirrtethylolpropane, pentaerythritol, inositol or similar sugar alcohols are also suitable crosslinkers. Acrylic or methacrylamides of ethylenedia in or other aliphatic di- or polyamines may be mentioned as further suitable crosslinking agents. In addition, diallyl maleate, diallyl fumarate or diallyl phthalate, triacryl- or trimethacrylamides, triallycyanurate or triallyl isocyanurate and vinylbenzenes such as divinylbenzene or trivinylbenzene can be used as crosslinkers.

The choice of crosslinker B14 depends on the type of network that the graft base B1 should have. For example, a compact network results when B131 is used with divinylbenzene, while a relatively loose network will hold if, for example, B131 is used together with tetraethylene glycol diacrylate or dimethacrylate. The particularly preferred crosslinker mixtures include dihydrodicyclopentadienyl acrylate and butanediol diacrylate; Dihydrodicyclopentadienyl acrylate and divinylbenzene; Dihydrodicyclopentadienyl acrylate and diethylene glycol diacrylate as well as dihydrodicyclopentadienyl acrylate and

Tetraethylene glycol di ethacrylate.

Also preferred are dihydrodicyclopentadienyl acrylate, butanediol diacrylate and allyl methacrylate; Dihydrodicyclopentadiene acrylate, butanediol diacrylate and hydroxyethyl acrylate; Dihydrodicyclopentadienyl acrylate, butanediol diacrylate and divinylbenzene; Dihydrodicyclopentadienyl acrylate, hydroxyethyl acrylate and divinylbenzene or diethylene glycol diacrylate or tetraethylene glycol dimethacrylate; Dihydrodicyclopentadienyl acrylate, hydroxyethyl acrylate, allyl methacrylate and divinylbenzene or diethylene glycol diacrylate or tetraethylene glycol dimethacrylate; Dihydrodicyclopentadienyl acrylate, allyl methacrylate, β-methacrylolyloxyethyldimethoxymethylsilane and divinylbenzene or diethylene glycol diacrylate or tetraethylene glycol dimethacrylate; Dihydroxydicyclopentadienyl acrylate, ß-methacrylolyloxyethyldimethoxymethylsilane and divinylbenzene or diethylene glycol diacrylate or tetraethylene glycol dimethacrylate.

The graft base B1 generally has a particle size (see above) of 80 nm or more, for example 200 nm or more. In general, particle sizes (see above) of 1000 nm are not exceeded. However, the graft bases according to the invention can also have larger particle sizes (ds ₀ ), for example up to 1200 nm, or up to 3000 nm. Particularly preferably, the graft - based on A a particle size (d) i ^m the range of 200 nm to 800 When specifying the average particle size is in all cases the weight average particle size as determined by means of an analytical ultracentrifuge by the method. Scholtan and Lange, Kolloid-Z. and Z. Polymers 250 (1972), pages 782 to 796. This procedure provides the integral mass distribution of the particle diameter of a sample. From this it can be seen what percentage by weight of the particles have a diameter equal to or smaller than a certain size. The average particle diameter, usually of the integral mass distribution is referred to as DSO ~ value is defined as the particle diameter at which 50 wt .-% of the particles have a diameter smaller than the diameter of which corresponds to the d ₅ o ~ value. Likewise, 50% by weight of the particles then have a larger diameter than the dςo value. The graft base B1 has, as a measure of the networking, in the

Usually a gel content of at least 90, preferably at least

95%, the gel content being the ratio of in the solvent

(Toluene) insoluble mass to total mass is defined. The swelling index is the ratio of swollen to unswollen mass in the solvent (toluene) and is for

Graft base generally 7 to 15.

According to the invention, the graft copolymers contain 5 to 90, preferably 20 to 90% by weight, based on the sum of B1 to B4, of a first graft shell (graft layer) B2. If Bl is missing, B2 forms the graft core. It is characteristic of B2 that the glass transition temperature T _{g is} at most 0 ° C, preferably at most -20 ° C, in particular from -100 to -30 ° C. The graft B2 particularly preferably forms a proportion of 40 to 70% by weight of the graft copolymer B, based on B1 to B4.

To graft B1 or to produce a graft shell B2, at least one monomer B21, usually at least one crosslinking monomer B22 and, if necessary, at least one further monomer B23 copolymerizable with B21 are copolymerized. The proportion of B21 according to the invention is 50 to 100% by weight, that of the crosslinking agent B22 0 to 20% by weight and that of the monomer B23 0 to 50% by weight. Preferred graft layers are composed of 60 to 99.9, in particular 65 to 99% by weight of B21, 0.1 to 10, in particular from 1 to 5% by weight of B22 and 0 to 39.9, in particular 0 to 30,% by weight. -% B23.

The weights given relate to the sum of components B21 to B23.

Suitable monomers B21 are acrylic acid alkyl esters, acrylic acid phenyl alkyl esters or acrylic acid phenoxy alkyl esters with up to 18 C atoms, in particular those with 2 to 8 C atoms in the alkyl radical, alone or as a mixture. In particular, n-butyl acrylate and 2-ethylhexyl acrylate are suitable, and mixtures thereof are suitable. Furthermore, all otherwise known rubber elastomer-forming monomers such as dienes, for example 1,3-butadiene, isoprene, dimethylbutadiene and organosiloxanes such as dimethylsiloxanes, can be used alone or in mixtures. Mixtures of alkyl acrylates and dienes in any composition are also possible.

Examples of the monomers B23 are acrylic acid or methacrylic acid derivatives different from B21, including preferably their esters or amides. In addition, preference is given to styrene, nucleus-substituted styrenes, α-methylstyrene, acrylonitrile, butadiene or iso- pren considered as copolymerizable monomers B23. Mixtures of different B23 monomers can of course also be used.

According to the invention, at least one crosslinking agent is used to produce component B2, it being possible to use the multifunctional monomers as described above with B131 and B132 for the preparation of the graft base B1. Of course, the respective proportions and monomer combinations can be selected independently of the production of B1.

The graft copolymers according to the invention are prepared in an emulsion, preferably in an aqueous emulsion.

The usual emulsifiers such as alkali metal salts of alkyl or alkylarylsulphonic acids, alkyl sulphates, fatty alcohol sulphonates, salts of higher fatty acids with 10 to 30 carbon atoms or resin soaps can be used for the production in aqueous emulsion. Sodium salts of alkyl sulfonates or of fatty acids with 10 to 18 carbon atoms are preferably used. Emulsifiers are preferably used in amounts of 0.3 to 5% by weight, in particular 1 to 2% by weight, based on the total weight of the monomers. The usual persulfates, such as potassium peroxodisulfate, are used in particular as polymerization initiators; however, redox systems which allow lower polymerization temperatures are also suitable. The amount of initiators (e.g. from 0.1 to 1% by weight, based on the total weight of the monomers used for the preparation of the graft base A) depends in a known manner on the desired molecular weight.

The usual buffer substances can be used as polymerization aids, by means of which a pH of preferably 6 to 9 is set, e.g. Sodium bicarbonate or sodium pyrophosphate. Further polymerization aids are molecular weight regulators, such as mercaptans, terpinols or dimeric α-methylstyrene. Molecular weight regulators are e.g. used in an amount of up to 3% by weight, based on the total weight of the monomers used for the preparation of the graft base B1.

To produce the graft base B1, a crosslinked seed latex is first prepared from a monomer B1, preferably styrene and at least one crosslinking monomer. In general, the seed latex has an average particle size dso of 20 to 200 nm, preferably from 50 to 100 nm. The seed latex is then treated with further monomers, crosslinking agents, emulsifiers, poly- merization aids and initiators implemented to the graft base B1.

It is advantageous to carry out the graft copolymerization of the monomers forming the components B2, likewise in aqueous emulsion, expediently in the same system as the polymerization of the graft base B1. Additional emulsifier and initiator can be added. These can, but do not have to, with the emulsifiers used for the production of B1 or

10 initiators must be identical. The emulsifier, initiator and polymerization auxiliaries can each be introduced alone or as a mixture together with the emulsion of the graft base B1. However, they can also be used alone or as a mixture together with the monomers used for the graft B2 to form the emulsion of B1.

15 will give. For example, the initiator and, as a polymerization aid, a buffer substance can be introduced together with the emulsion of the graft base B1, and then the monomers for the graft pads B2 can be added dropwise together with the emulsifier.

20th

The easiest way to polymerize B1 and B2 in succession is in the same vessel ("one-pot process"). The ratio of the feed rates (feed ratios) ZI and Z2 to one another is 0.05 to 10, preferably 0.1 to 10 and particularly preferably 0.2 to 3.

25 ZI means the ratio of the amount of monomers B1 to B14 [g / h] to the amount of monomers B21 to B23 [g / h]; Z2 means the ratio of the amount of emulsifier for Bl [g / h] to the amount of emulsifier for B2 [g / h].

The graft copolymerization is generally controlled so that a mass ratio of graft base B1 to graft B2 of preferably 1: 0.5 to 1:20, particularly preferably 1: 1 to 1:10 results. Very particularly preferred graft copolymers according to the invention have mass ratios of B1 to B2 of

35 1: 3 to 1: 8.

In addition to the components B1 (if appropriate) and B2, the graft copolymers according to the invention have a second or first graft shell B3 with a glass transition temperature of at least 40-25 ° C. This should contain from 5 to 90% by weight, preferably from 15 to 50% by weight, particularly preferably from 25 to 50% by weight, based on components B1 to B3, in the graft copolymers according to the invention his.

For its part, 45 B3 generally consists of 0 to 100% by weight of at least one vinyl aromatic monomer B31; 0 to 20% by weight of at least one polyfunctional, moisturizing monomer B32, such as given above for example for B22; 0 to 100% by weight of cyclohexyl acrylate (B33) and 0 to 100% by weight of one or more copolymerizable unsaturated monomers B34: the latter

Monomers can correspond to the type of monomers B23 mentioned above.

Another graft cover B14 can be provided. If such a further graft shell B14 is to be applied, it can contain any monomers.

It is advantageous to carry out the graft copolymerization of the further graft layers B13 and optionally B14 again in aqueous emulsion in the presence of the graft copolymer from B1 and B2 or B2 which serves as the graft base. However, like the preparation of the graft base B1 and the first graft shell B2, the graft polymerization can be carried out in suspension, in bulk or in solution. It can be carried out in the same system as the polymerization of the graft copolymer from B1, B2 and, if appropriate, B3, it being possible to add further emulsifier and initiator. These may, but do not need to be identical to those for producing the graft base B1 and the graft pads B2 and possibly B3. For the rest, the same applies to the choice and combination of emulsifiers and polymerization auxiliaries and to the choice of the production process as was said for the preparation of the graft base B1.

The graft copolymers according to the invention generally have average particle sizes (dso) from 100 to 10,000, preferably from 250 to 5000 nm. Particularly preferred graft copolymers according to the invention have average particle diameters (d ₅₀ ) in the range from 500 to 2000 nm, for example 500 to 800 nm or 800 to 12000 nm. The graft copolymers according to the invention can have both a narrow and a broad particle size distribution. They preferably have a narrow particle size distribution. The graft copolymer B can also be a mixture of particles of two different size classes; The corresponding (dso) values can form, for example, pairs of 100 and 500 nm, 400 and 800 nm or 400 and 1500 nm (so-called "bimodal particle size distribution"). The particle size distribution is defined as the quotient Q = (d ₉ o-dι ₀ ) / d ₅₀ . The (dχ ₀ ) and (dgo) values are defined according to the (dso) value, but refer to a frequency of 10 and 90% by weight of all particles. Particularly preferred graft copolymers according to the invention have Q values of 0.3 or less, in particular 0.15 or less. Of course, the production of the particulate graft copolymers B is also possible by all other known processes in solution, mass, suspension, microsuspension or by combined processes. Bulk suspension methods and microsuspension methods are preferably used when particle sizes of more than 1000 nm are to be set.

Preferably, if the rubber particles are to be bimodally distributed, but also in other cases of modification, the molding compositions according to the invention can also contain a further graft copolymer in an amount of, for example, up to 90% by weight, based on the first graft copolymer . This graft copolymer B 'can, for example, consist of a core made of rubber-like material with a glass transition temperature T _g below 25 ° C. and at least one further graft shell with T _g above 25 ° C. What has been said for B applies to the composition of this graft rubber, its production and the particle sizes that can be considered.

However, it is also possible to obtain a bimodal distribution of the particle sizes during a single, multi-stage emulsion polymerization by means of suitable measures. This is achieved, for example, by the targeted addition of seed latices during the reaction, e.g. dso values (distribution maxima) around 170 on the one hand and around 500nm on the other hand can be observed.

additions

The thermoplastic molding composition according to the invention can furthermore contain one or more further polymers or copolymers (C) of vinylaromatic compounds, for example polystyrene, styrene-butadiene block copolymers and other polymers compatible with A, such as e.g. Polyphenylene ether D. The other polymers C and D can e.g. each have a proportion of up to 90% by weight, based on the total mass, with correspondingly reduced proportions of the other constituents.

The thermoplastic molding composition according to the invention can furthermore contain up to 90% by weight of at least one customary additive E. However, its proportion is usually not more than 50, preferably 0.1 to 20% by weight, based on the total weight of A. to E.

Common additives are, for example, glass fibers, flame retardants, stabilizers and antioxidants, agents against

Thermal decomposition and decomposition by ultraviolet light, lubricants and mold release agents, dyes and pigments or plasticizers. Glass fibers made of E, A or C glass can be used. The glass fibers are usually equipped with a size and an adhesion promoter. The diameter of the glass fibers is generally between 6 and 20 µm. Both continuous fibers (rovings) and chopped glass fibers with a length of 1 to 10 mm, preferably 3 to 6 mm, can be incorporated.

Pigments and dyes are generally present in amounts of up to 6, preferably from 0.5 to 5 and in particular from 0.5 to 3% by weight, based on A to E.

The pigments for coloring thermoplastics are generally known, see, for example, R. Gächter and H. Müller, Taschenbuch der Kunststoffadditive, Carl Hanser Verlag, 1983, pp. 494 to 510. White pigments such as zinc oxide and zinc sulfide are to be mentioned as the first preferred group of pigments , Lead white (2 PbC0 ₃ -Pb (OH) ₂ ), lithopone, antimony white and titanium dioxide. Of the two most common crystal modifications (rutile and anatase type) of titanium dioxide, the rutile form is used in particular for the white coloring of the molding compositions.

Black color pigments that can be used are iron oxide black (Fe ₃ 0), spinel black (Cu (Cr, Fe) 0 ₄ ), manganese black (mixture of manganese dioxide, silicon dioxide and iron oxide), cobalt black and antimony black and particularly preferably carbon black, which is mostly in Form of furnace or gas black is used (see G.Benzing, Pigments for paints, Expert Verlag (1988), p.78ff).

Of course, inorganic colored pigments such as chrome oxide green or organic colored pigments such as azo pigments or phthalocyanines can be used to adjust certain shades. Pigments of this type are generally commercially available.

Oxidation retarders and heat stabilizers which can be added to the thermoplastic molding compositions according to the invention are e.g. Group I metals of the Periodic Table, e.g. Sodium, potassium, lithium halides, optionally in combination with copper (I) halides, e.g. Chlorides, bromides or iodides. The halides, especially of copper, can also contain electron-rich p-ligands. Examples of such copper complexes are Cu halide complexes with e.g. Called triphenylphosphine. Zinc fluoride or zinc chloride can also be used. Sterically hindered phenols, hydroquinones, are substituted representatives of these

Group, secondary aromatic amines, optionally in combination with phosphorus-containing acids or their salts, and mixtures of these compounds, preferably in concentrations up to

1% by weight, based on components A to E, can be used.

Examples of UV stabilizers are various substituted resorcinols, salicylates, benzotriazoles and benzophenones, which are generally used in amounts of up to 2% by weight, based on components A to E.

Lubricants and mold release agents, which are generally added in amounts of up to 1% by weight of the thermoplastic molding compositions, are stearic acid, stearyl alcohol, alkyl stearates and amides, and esters of pentaerythritol with long-chain fatty acids. Salts of calcium, zinc or aluminum of stearic acid and dialkyl ketones, e.g. Distearyl ketone can be used.

Examples of plasticizers are dialkyl phthalates such as dioctyl phthalate.

The thermoplastic molding compositions can be produced by processes known per se by mixing the components in conventional mixing devices such as screw extruders, Brabender mills or Banbury mills and then extruding them. After the extrusion, the extrudate is cooled and crushed.

The thermoplastic molding compositions are characterized by high heat resistance with good impact strength. At the same time, the thermoplastic molding compositions have a high resistance to weathering and aging. They are also easy to color.

They can be processed into moldings, foils or fibers. They can also, for example, by means of known coextrusion processes in the form of layers (preferably in layer thicknesses in the range from 100 μm to 10 mm) on surfaces, preferably on

Thermoplastics such as styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene terpolymers (ABS), polystyrene, and impact-resistant polystyrene (HIPS) are applied. The molding compositions can be used, for example, in the automotive, household and electrical sectors and for leisure articles. Examples

Purification of 1,1-diphenylethylene (DPE)

Crude DPE (Aldrich or production by reacting phenylmagnesium bromide with acetophenone, acetylation with acetic anhydride and thermal elimination of acetic acid) is brought to 99 over a column with at least 50 theoretical plates (rotating band column; for larger quantities, column with Sulzer packings) , 8% purity distilled. The mostly pale yellow distillate is filtered through a 20 cm Alox column (Woelm alumina for chromatography, anhydrous), titrated with 1.5 N sec-butyllithium until a strong red color and over a simple bridge in a vacuum (1 mbar) distilled off. The product thus obtained is completely colorless and can be used directly in the anionic polymerization.

Polymerizations

Solutions with living anions were generally handled under the purest nitrogen. The solvents were dried over anhydrous alumina.

In the following examples, S stands for styrene and DPE for 1, 1-diphenylethylene and the data in% relate to the weight, unless stated otherwise.

Measurements

The particle sizes (weight average values dso) were determined using an ultracentrifuge using the method of Scholtan and Lange, Kolloid-Z. and Z. Polymers 250 (1972) pages 782 to 796 and from this the integral mass distribution of the particle diameters was determined. The mean particle diameter (dso ~ value of the integral mass distribution) is the value at which 50% by weight of the

Particles have a diameter below or above the dso value.

example 1

Poly [S-block- (S-co-DPE)] as hard component A

A carefully inertized 10 1 stirred kettle was charged at 23 ° C with 5120 ml cyclohexane, 1115 ml (1012 g; 9.71 mol) styrene and 50 ml sec-butyllithium (0.289 m in cyclohexane), adjusted to 70 ° C and after 100 minutes cooled to 50 ° C and 1113 ml

(1139 g; 6.32 mol) titrated 1,1-diphenylethylene was added. Now 2022 ml (1834 g; 17.62 mol) of styrene were in every 10 minutes WO 98/36026 _{Λ Λ} PCT / EP98 / 00596 -

20th

200 ml steps added. After 180 min the mixture was titrated to colorlessness with ethanol, the polymer solution by dropping in

Ethanol precipitated, washed several times with ethanol and at 2 hours

200 ° C i. V. dried.

5

Weight: 3909 g (98.1%); Styrene content (FTIR): 71.3% (calc.

71.4%); DPE content (FTIR): 28.7% (calc. 28.6%); T _g (DSC): first stage 110 ° C (latitude: 11 ° C); second stage 148 ° C (latitude 18 ° C); Molar masses (GPC; polystyrene standard): M _n : 140,000 g / mol, M _w : 209,000

10 g / mol, M _pea max. : 246,000 g / mol.

Soft component B (graft rubber with PBA core)

Graft base

15

Commercial K-Cι ₂ _i ₈ -paraffin sulfonate was used as an emulsifier. An emulsion of 3.2 g tricyclodecenyl acrylate, 156.8 g n-butyl acrylate, 10 g emulsifier, 3 g potassium peroxodisulfate (KPS), 3 g sodium hydrogen carbonate and 1.5 g sodium pyrophosphate in 1500

20 g of water were heated to 65 ° C. with stirring. 10 minutes after the onset of the reaction, a further 16.8 g of tricyclodecenyl acrylate and 823.2 g of n-butyl acrylate were metered in over the course of 3 hours and the mixture was kept at 65 ° C. for another hour. Solids content 9.5% by weight.

25

12.5 g of the polybutyl acrylate dispersion obtained were heated to 65 ° C. with 1500 g of water with the addition of 3.0 g of KPS, 3.0 g of sodium hydrogen carbonate and 1.5 g of sodium pyrophosphate. 20.0 g of tricyclodecenyl - were

30 acrylate, 980 g of n-butyl acrylate and 3.0 g of K-Cι ₂ _ _{! 8-} paraffin sulfonate were metered in and kept at 65 ° C. for one hour. The latex obtained now had a solids content of 40%.

1900 g of latex were kept under stirring with a further 900 g of water and 35 1.0 g of potassium peroxodisulfate until the reaction started at 65 ° C., 4 g of emulsifier and then a mixture of 3.5 g of tricyclodecenyl acrylate and 168 g of styrene within one hour added and kept at 65 ° C for one hour; a further 3400 g of water, 6.5 g of NaHC0 ₃ and 5.0 g of KPS were added, 40 1600 g of n-butyl acrylate, 34 g of dicyclopentadienyl acrylate and 50 g of butanediol diacrylate and 10 g of emulsifier were metered in at 65 ° C. in the course of 3 hours and one Stirred at 65 ° C for an hour.

45 Graft cover

6400 g of the dispersion obtained were diluted with 2000 g of water, 5.5 g of KPS and 7.0 g of emulsifier were added, and 900 g of styrene and 50 g of acrylonitrile were metered in over> 3.5 hours and the mixture was stirred at 65 ° C. for a further 2 hours ( Solids content: 31%). Average particle size of the graft polymer 800 nm. The graft polymer was precipitated using calcium chloride solution at 95 ° C., washed with water and dried in a warm air stream.

10

Mixtures

The molding compositions were produced by melt mixtures. 3 kg each of components A and B were mixed in a commercially available 15 extruder (Werner & Pfleiderer, model ZSK 30) at a melt temperature of 250 ° C. Test specimens were injected from the extrudate at 220 ° C. The key figures determined are listed in the table below.

20 Example 2

The poly [S-block (S-co-DPE)] described in Example 1 was used as the hard component A and the ABS graft rubber described below as the soft component B.

25

Graft base

By polymerizing 60 parts of butadiene in the presence of a solution of 0.5 parts tert. -Dodecyl mercaptan, 0.7 parts sodium

30 stearate as emulsifier, 0.2 part of potassium peroxodisulfate and 0.2 part of sodium pyrophosphate in 80 parts of water, a polybutadiene latex is produced at 65 ° C. and a pressure of 3 bar. The pressure is released and the vacuum is reduced until the butadiene content reaches below 10 ppmd (parts per million dispersiön). middle

35 particle size of the polybutadiene latex 0.1 μm.

It is agglomerated by adding 11.5 parts of a 10% strength aqueous acetic anhydride solution to an average particle size of 0.5 to 0.7 μm and stabilized against coagulation by adding 40 parts of 0.6 part of Na-C ₈ i sulfonate.

Graft cover

140 parts of polybutadiene latex were mixed with 40 parts of a 45 95/5 mixture of styrene-acrylonitrile and 50 parts of water, 0.08 part of KPS and 0.05 part of lauroyl peroxide were added with stirring and the mixture was kept at 65 ° C. for 3 hours . After that, with 1%, based on polymer, commercially available 2,6-di-tert-butyl-4-methylphenol stabilized, precipitated with 60% sulfuric acid at 95 ° C, washed with water and dried in a warm air stream. 5

Mixture of A and B as described in Example 1.

Comparison test

10 hard components of commercially available SAN polymer (styrene / acrylonitrile 67:33 w / w; VZ = 78).

Soft component butyl acrylate rubber with PSAN graft shell, manufactured as follows:

15

4400 g of water, 40 g of n-butyl acrylate latex (40 wt .-% in water; ₅ d o = 80 nm) as a seed latex, 9.2 g of potassium peroxodisulfate, 9 g of sodium bicarbonate and 4.5 g of sodium pyrophosphate were on stirring Heated to 65 ° C. Separate from one another

20 mixture of 2940 g of n-butyl acrylate and 60 g of DCPA and a solution of 18 g of Na ₂ -C ₈ -paraffin sulfonate were added over the course of 3 hours. Average particle diameter d ₅ o of the obtained latex 450 nm; Solids content 39.8%.

25 4560 g of latex were heated with 2600 g of water, 4.8 g of potassium peroxodisulfate with stirring to 65 ° C. and a mixture of 390 g of styrene and 6.0 g of emulsifier for one hour and a mixture of 600 g of styrene and for two more hours 200 g of acrylonitrile gradually added. After the addition has ended, add 2 hours

30 65 ° C kept. (Solids content 34.8%; average particle size 510 nm.

It was precipitated using calcium chloride solution at 95 ° C., washed with water and dried in a warm air stream.

35

Table 1: Vicat softening temperature [° C] according to DIN 53460

40

5

Claims

claims

1. Containing mixture, based on the sum of A and B:

A: 50 to 90% by weight of at least one hard polymer A with a glass transition temperature T _g of above 25 ° C. selected from copolymers AI of 50 to 99 mol% of polymerized units of styrene and 1 to 50 mol% of polymerized units of 1 , 1-Diphenyl-ethylene and / or block copolymers A2, which have at least one polystyrene block and at least one poly (styrene / diphenylethylene) block of the above composition, as by anionic block (co) polymerization of styrene or styrene and

1, 1-diphenylethylene can be obtained;

B: 10 to 50% by weight of a particulate graft copolymer B with at least one glass transition temperature T _g of below -10 ° C., based on the sum of B1 to

B3 or B1 to B4, if applicable:

Bl: 0 to 90% by weight of a first graft core Bl with a glass transition temperature Tg of more than 25 ° C., based on the sum of B1 to B14;

B14: 0 to 50% by weight of one or more copolymerizable monomers;

B2: 5 to 90% by weight of a first graft shell B2 or a graft core with a freezing temperature T _g of below

0 ° C off, based on the sum of B21 to B24: B21: 50 to 99.9% by weight of at least one alkyl acrylate,

Siloxane diene or EPDM rubbers;

B22: 0.1 to 20% by weight of at least one polyfunctional, crosslinking and / or grafting monomer B22 with two or more functional groups of different reactivity, which can have crosslinking and grafting activity at the same time;

B3: 5 to 90% by weight of a (optionally second) graft shell B3 with a glass transition temperature T _g of more than 25 ° C., based on the sum of B31 to B34:

B31: 5 to 100% of at least one vinyl aromatic monomer;

B32: 0 to 20% of at least one polyfunctional, crosslinking and / or graft-active monomer B32 with two or more functional groups of different reactivity, which can simultaneously have crosslinking and graft-active action;

B33: 0 to 95% cyclohexyl methacrylate;

B34: 0 to 95% of one or more copolymerizable unsaturated monomers B34;

B4: 0 to 50 wt .-% of at least one further, B2 and / or B3 B4 various graft with a glass transition temperature Tg of more than 25 ° C, wherein the spatial order of the Pfrop ^'fhüllen B2, B3 and B4, where appropriate, any with the proviso that between the

Graft core B1 and the graft shell B4 at least one of the graft shells B2 and B3 is arranged.

2. Mixture according to claim 1, wherein the spatial order of the components B1, B2, B3 and optionally B4 is arbitrary with the proviso that either the graft core or at least one graft shell has a freezing temperature T _g of below 25 ° C and either the graft core or at least a graft shell have a freezing temperature T _g of over 25 ° C.

3. Mixture according to claim 1, comprising a particulate

Graft copolymer B with an average particle diameter

(d ₅₀ ) from 100 to 10000 nm.

4. Mixture according to claim 1, comprising at least 2 graft rubbers B and B ', where B and B' differ from one another in terms of their particle size (dso) and / or their composition.

5. Molding composition comprising a mixture as claimed in claim 1, based on the sum of A to E:

A: 5-95% of at least one copolymer A;

B: 5-95% of at least one graft rubber B; as well as a total of at least 1% by weight of the following further constituents C, D and E:

C: 0-90% of at least one further copolymer C;

D: 0-90% of at least one polyphenylene ether D;

E: 0-90% of at least one common additive E.