WO1997041174A2

WO1997041174A2 - Mouldings made of thermoplastic moulding masses

Info

Publication number: WO1997041174A2
Application number: PCT/EP1997/002099
Authority: WO
Inventors: Gerhard Lindenschmidt; Bernhard Rosenau; Graham Edmund Mc Kee; Wolfgang Fischer
Original assignee: Basf Aktiengesellschaft
Priority date: 1996-04-29
Filing date: 1997-04-24
Publication date: 1997-11-06
Also published as: DE19617068A1; WO1997041174A3; EP0896606A2

Abstract

Mouldings made of thermoplastic moulding masses contain (A) 30 to 99 wt %, relative to the total weight of the moulding mass, of a thermoplastic polymer, comprising, relative to (A): (a1) 50 to 100 wt % of a styrene compound of general formula (I), in which R?1 and R2¿ stand for hydrogen or C¿1?-C8 alkyl, or a (C1-C8-alkyl)ester of acrylic or methacrylic acid, or mixtures of the styrene compound and of the (C1-C8-alkyl)ester of acrylic or methacrylic acid; (a2) 0 to 40 wt % acryl nitrile or methacryl nitrile or their mixtures; and (a3) 0 to 40 wt % of one or several other monoethylenically unsaturated monomers different from (a2); (b) 1 to 70 wt %, with respect to the total weight of the moulding mass, of a graft polymer comprising, relative to (B): (b1) 30 to 90 wt % of a rubber-elastic grafted core made of a polymer with a glass transition temperature below 0 °C and obtained by copolymerising (b11) 50 to 99.99 wt %, with respect to (b1), of a (C1-C10-alkyl)ester of acrylic acid; (b12) 0.01 to 10 wt % of a polyfunctional, cross-linking monomer; and (b13) 0 to 40 wt % of one or several others monoethylenically unsaturated monomers different from (b11); and (b2) 10 to 70 wt % of a grafted sheath which contains, relative to (b2): (b21) 50 to 100 wt % of a styrene compound of general formula (I), in which R?1 and R2¿ stand for hydrogen or C¿1?-C8-alkyl; or a (C1-C8-alkyl)ester of acrylic acid or methacrylic acid; or mixtures of the styrene compound and of the (C1-C8-alkyl)ester of acrylic or methacrylic acid; (b22) 0 to 40 wt % acryl nitrile or methacryl nitrile or their mixtures; and (b23) 0 to 40 wt % of one or several other monoethylenically unsaturated monomers.

Description

^• Molded parts made from thermoplastic molding compounds

description

Molded parts made from thermoplastic molding compositions which contain

A) 30 to 99% by weight, based on the total weight of the molding composition, of a thermoplastic polymer, based on A)

al) 50 to 100 wt .-%, a styrene compound of the general formula

R2

in which R ¹ and R ^{2 are} hydrogen or C 1 -C ₈ -alkyl,

or

one (Ci-Ca-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the

(C _I -C _B alkyl) esters of acrylic acid or methacrylic acid

a2) 0 to 40% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

a3) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers different from a2),

B) 1 to 70% by weight, based on the total weight of the molding composition, of a graft polymer, based on B),

bl) 30 to 90% by weight of a rubber-elastic graft core made of a polymer with a glass transition temperature below 0 ° C., obtainable by copolymerization of, based on bl), bll) 50 to 99.99% by weight of a (-CC ₁₀ -alkyl) ester of acrylic acid,

bl2) 0.01 to 10% by weight of a polyfunctional, crosslinking monomer, and

bl3) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers different from bll), and

b2) 10 to 70% by weight of a graft shell, based on b2),

b21) 50 to 100% by weight of a styrene compound of the general formula

R ²

in which R ¹ and R ^{2 are} hydrogen or C 1 -C ₈ -alkyl,

or

a (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the (-C ₈ alkyl) ester of acrylic acid or methacrylic acid

b22) 0 to 40% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

b23) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers.

The term "molded parts" in the sense of this invention also includes semi-finished products (such as pipes, profiles, plates) and foils.

Furthermore, the invention relates to molded parts containing special components A) and B) or additives, and to the use of the molded parts as visual and weather protection parts in the construction sector. “Construction sector” is to be understood here as building construction, civil engineering, construction of traffic routes, landscaping and gardening.

Molded parts made of plastics have a wide range of uses, since plastics can be used to produce complex geometries or even large-area molded parts in technically sophisticated processes such as the injection molding process or extrusion and subsequent thermoforming.

When plastics are used outdoors, particularly in the construction sector, adequate resistance to weather influences, in particular UV radiation, frost temperatures, temperature changes, water and chemicals (for example cleaning agents) must be ensured. In spite of their good low-temperature impact strength, molding compositions modified with polymers from conjugated dienes, for example polybutadiene rubber, are therefore less suitable for outdoor use, since the C = C double bonds remaining in the rubber molecules are attacked by UV radiation, from which weathering of the surface, visible as graying or yellowing, and aging, recognizable by a deterioration in the mechanical properties.

For this reason, weather-resistant plastics, especially polyvinyl chloride (PVC), are used in the construction sector, especially for privacy and weather protection parts such as roller shutters, blinds, panels, canopies, gutters, etc. Profiles (e.g. for roller shutters, panels), pipes and plates are usually manufactured by extrusion, possibly further processed by deformation under the influence of heat (so-called thermoforming), and with parts that are produced by injection molding, e.g. Profile end caps, brackets, etc., complete.

PVC has advantages over other materials such as wood or aluminum, in particular ease of maintenance, good thermal insulation and resistance to rotting.

However, weathering and exposure to chemicals, eg cleaning agents, can lighten the PVC. These color changes, also known as "chalking", are based on degradation processes in PVC and are particularly troublesome when the PVC is colored dark. The chalking also causes a roughening of the surface and thus a loss of gloss. These signs of aging interfere particularly with light-colored colors. For molded parts that are exposed to higher temperatures, such as hot water pipes, the low heat resistance of PVC proves to be a disadvantage.

The production of the above-mentioned, complementary injection molded parts (end caps, holders) made of PVC is difficult because the PVC melt accelerates the degradation of the PVC. The hydrogen chloride formed as a degradation product can lead to severe corrosion on the processing machines and tools.

A low weight is aimed in particular for visual and weather protection components that have to be moved (windows, blinds, roller shutters). The high density of PVC compared to other polymers is therefore a disadvantage.

The object of the invention was therefore to provide molded parts which do not have the disadvantages described, which, in particular with high impact strength, have good weather resistance, permanent coloration (high color stability), high surface gloss, good heat resistance, and low weight, and are problem-free are processable by injection molding.

Accordingly, the molded parts defined at the outset were found. Furthermore, moldings were found which contain certain thermoplastic polymers A) and certain graft polymers B). Finally, the use of the molded parts as visual and weather protection parts was found in the construction sector.

Component A) of the molding compositions from which the moldings according to the invention consist is in a proportion of 30 to 99, preferably 35 to 95 and particularly preferably 45 to 80% by weight, based on the sum of components A) and B), included in the masses.

Component A) is obtained by polymerizing a monomer mixture based on A),

al) 50 to 100, preferably 60 to 95 and particularly preferably 60 to 90% by weight of a styrene compound of the general formula I.

in which R ¹ and R ^{2 are} hydrogen or -CC ₈ alkyl or

one (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid

or mixtures of the styrene compound and the

(Ci-Ca-alkyl) esters of acrylic acid or methacrylic acid,

a2) 0 to 40, preferably 5 to 38% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

a3) 0 to 40, preferably 0 to 30% by weight of one or more further monoethylenically unsaturated monomers different from a2).

Component A) preferably has a glass transition temperature T _g of 50 ° C. or above. A) is therefore a hard polymer.

The styrene compound of the general formula (I) (component a1)) is preferably styrene, α-methylstyrene and, moreover, styrenes which are core-alkylated with C 1 -C 6 -alkyl, such as p-methylstyrene or tert-butylstyrene. Styrene is particularly preferred.

Instead of the styrene compounds or in a mixture with them, ci- to Cβ-alkyl esters of acrylic acid and / or methacrylic acid are suitable, especially those which are derived from methanol, ethanol, n- and iso-propanol, sec.-, tert.- and iso -Butanol, pentanol, hexanol, heptanol, octanol, 2-ethylhexanol and n-butanol are derived. Methyl methacrylate is particularly preferred.

Component A) may further contain one or more further monoethylenically unsaturated monomers a3) at the expense of monomers al) and a2), which vary the mechanical and thermal properties of A) within a certain range. Examples of such comonomers are:

N-substituted maleimides such as N-methyl, N-phenyl and N-cyclohexylimaleimide;

Acrylic acid, methacrylic acid, furthermore dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and their anhydrides such as maleic anhydride;

Nitrogen-functional monomers such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, vinylimidazole, vinylpyrrolidone, vinylcaprolactam, vinylcarbazole, vinylaniline, acrylamide and methacrylamide; aromatic and araliphatic esters of acrylic acid and methacrylic acid, such as phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate, 2-phenoxyethyl acrylate and 2-phenoxyethyl methacrylate;

unsaturated ethers such as vinyl methyl ether,

as well as mixtures of these monomers.

Preferred components A) are, for example:

A / l: polymethyl methacrylate (PMMA) - in this case A) is obtainable by polymerizing 100% by weight of methyl methacrylate (component al)),

A / 2: Polymers obtainable by polymerization of 70 to 99, preferably 90 to 99% by weight of methyl methacrylate and 1 to 30, preferably 1 to 10% by weight of styrene, styrene completely or partly by (C ₂ to Cg Alkyl) esters of acrylic acid or methacrylic acid can be replaced,

A / 3: polymers, obtainable by copolymerization from 40 to

90, preferably 50 to 80% by weight of styrene and / or α-methylstyrene a1), with 10 to 60, preferably 20 to 40% by weight of acrylonitrile a2), and optionally 0 to 30, preferably 0 to 20% by weight % of further monoethylenically unsaturated monomers a3) different from a2).

If component A) preferably contains styrene and acrylonitrile, the known commercially available SAN copolymers are formed. They generally have a viscosity number VZ (determined according to DIN 53 726 at 25 ° C, 0.5% by weight in dimethylformamide) of 40 to 160 ml / g, corresponding to an average molecular weight of about 40,000 to 250,000 (weight average).

Component A) can be used in a manner known per se, e.g. obtained by substance, solution, suspension, precipitation or emulsion polymerization. Details of these methods are e.g. in the plastics handbook, ed. Vieweg and Daumiller, Carl-Hanser-Verlag Munich, vol. 1 (1973), pp. 37 to 42 and vol. 5 (1969), pp. 118 to 130, as well as in Ulimann's encyclopedia of technical chemistry, 4th edition, Verlag Chemie Weinheim, vol. 19, pp. 107 to 158 "Polymerization technology".

Component B) of the molding compositions from which the moldings according to the invention consist is in a proportion of 1 to 70, preferably 5 to 65 and particularly preferably 20 to 55% by weight, based on the sum of components A) and B) contained in the masses. This component is a particulate graft copolymer which is composed of a rubber-elastic graft core bl) made of a polymer with a glass transition temperature below 0 ° C. (“soft component”) and a graft shell b2) (“hard component”) grafted onto it is.

The graft core bl) is present in a proportion of 30 to 90, preferably 35 to 80 and particularly preferably 50 to 80% by weight, based on component B).

The graft core bl) is obtained by polymerizing a monomer mixture, based on bl)

bll) 50 to 99.99, preferably 80 to 99.7 and particularly preferably 85 to 99% by weight of a (-CC-alkyl) ester of acrylic acid,

bl2) 0.01 to 10, preferably 0.3 to 10 and particularly preferably 1 to 4% by weight of a polyfunctional crosslinking monomer, and

bl3) 0 to 40, preferably 0 to 20% by weight and particularly preferably 0 to 10% by weight of one or more further monoethylenically unsaturated monomers different from B1).

Suitable acrylic acid alkyl esters B1) are primarily those derived from ethanol, from 2-ethylhexanol and especially from n-butanol. 2-ethylhexyl acrylate and very particularly n-butyl acrylate are preferred. Mixtures of different acrylic acid alkyl esters B1) which differ in their alkyl radical can also be used.

Crosslinking monomers bl2) are bifunctional or polyfunctional comonomers with at least 2 olefinic, non-conjugated double bonds, for example butadiene and isoprene, divinyl esters of dicarboxylic acids such as succinic acid and adipic acid, diallyl and divinyl ethers of bifunctional alcohols such as ethylene glycol and butane-1 , 4-diols, diesters of acrylic acid and methacrylic acid with the bifunctional alcohols mentioned, 1,4-divinylbenzene and triallyl cyanurate. The acrylic acid ester of tricyclodecenyl alcohol of the following formula is particularly preferred

which is known under the name dihydrodicyclopentadienyl acrylate, and the allyl esters of acrylic acid and methacrylic acid.

The other monoethylenically unsaturated monomers bl3) which may be present in the graft core bl) at the expense of the monomers bll) and bl2) are, for example:

vinyl aromatic monomers such as styrene, styrene derivatives of the general formula _R 2

in which R ⁱ and R ^{2 are} hydrogen or C 1 -C ₈ -alkyl;

Acrylonitrile, methacrylonitrile;

Ci to C ₄ alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, ethylhexyl acrylate and the corresponding esters of methacrylic acid, - furthermore also the glycidyl esters, glycidyl acrylate and methacrylate;

furthermore the monomers mentioned for component a3);

as well as mixtures of these monomers.

Preferred monomers b1) are styrene, acrylonitrile, methyl methacrylate, glycidyl acrylate and methacrylate, acrylamide and methacrylamide.

The glass transition temperature of the graft core bl) is determined by the DSC method, as described in the publication H. Illers, Makromol. Chemie 127 (1969), pp. 1 ff.

The graft shell b2) is present in a proportion of 10 to 70, preferably 20 to 65 and particularly preferably 20 to 50% by weight, based on component B), and is obtained by polymerizing a mixture of monomers on b2),

b21) 50 to 100, preferably 60 to 95 and particularly preferably 60 to 90% by weight of a styrene compound of the general formula R ²

in which R ¹ and R ^{2 are} hydrogen or -CC ₈ alkyl,

or

10 of a (Ci-C _ß- alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the (-CC ₈ -alkyl) ester of acrylic acid or methacrylic acid,

15 b22) 0 to 40, preferably 0 to 30% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

b23) 0 to 40, preferably 0 to 20% by weight of one or more further monoethylenically unsaturated monomers.

With regard to the monomers b21) and b23), reference is made to the comments on the components al) and bl3). Accordingly, the graft shell b2) can contain further monomers 25 b22) and / or b23) at the expense of the monomers b21). The graft shell b2) is preferably composed of polymers as mentioned as preferred embodiments A / 1, A / 2 and A / 3 of component A).

The graft polymers B) are obtained in a manner known per se, preferably by emulsion polymerization at 30 to 80 ° C. Suitable emulsifiers for this purpose are, for example, alkali metal salts of alkyl or alkylarylsulfonic acids, alkyl sulfates, fatty alcohol sulfonates, salts of higher fatty acids with 10 to 30 carbon atoms, sulfosuccinates, ether sulfonates or resin soaps. The alkali metal salts of alkyl sulfonates or fatty acids having 10 to 18 carbon atoms are preferably used.

Sufficient water is preferably used to prepare the dispersion so that the finished dispersion has a solids content of 40 20 to 50% by weight.

Free radical formers, for example peroxides such as peroxosulfates and azo compounds such as azodiisobutyronitrile, are preferably used as polymerization initiators. However, redox systems, especially those based on hydroperoxides such as cumene hydroperoxide, can also be used. Molecular weight regulators such as ethylhexylthioglycolate, t-dodecyl mercaptan, terpinols and dimeric α-methylstyrene with

. use.

To maintain a constant pH value, which is preferably 6 to 9, buffer substances such as Na ₂ HPO ₄ / NaH ₂ PO ₄ or sodium hydrogen carbonate can also be used.

Emulsifiers, initiators, regulators and buffer substances are used in the usual amounts, so that further details are unnecessary.

The graft core can particularly preferably also be prepared by polymerizing the monomers b1) in the presence of a finely divided rubber latex (so-called "seed latex mode of operation" of the polymerization), as described, for example, in DE-A 28 26 925 is.

In principle, it is also possible to prepare the graft base using a method other than that of emulsion polymerization.

20 places, e.g. by bulk, suspension or solution polymerization, and subsequently emulsifying the polymers obtained. Microsuspension polymerization is also suitable, preference being given to using oil-soluble initiators such as lauroyl peroxide and t-butyl perpivalate. The procedures for this are

25 known.

The reaction conditions are preferably coordinated with one another in a manner known per se so that the polymer particles have a diameter d 50 (particle size distribution) which is as uniform as possible in the range from 60 to 1000, in particular from 80 to 650 nm.

Instead of a uniform graft polymer B), it is also possible to produce various molded parts according to the invention

Use 35 of these polymers B), especially those with significantly different particle sizes. Acrylic ester polymer mixtures of this type with a bimodal size distribution offer procedural advantages in further processing. Suitable particle diameters are in the range from 60 to 200 nm on the one hand and

40 300 to 1000 nm on the other hand, see, for example, EP-A 6 503.

The graft shell b2) can be produced in one or more, for example two or three, process steps. The monomers b21), b23) can be added to the polymerization reactor individually or as a mixture with one another. The monomer ratio in the mixture can be constant over time or a gradient. Combinations of these procedures are also possible. The Gross composition remains unaffected by the above-mentioned configurations of the process.

Graft polymers with several "soft" and "hard" stages, e.g. of the structure bl) -b2) -bl) -b2) or b2) -bl) -b2), especially in the case of larger particles.

Larger graft particles B) can preferably also be produced in a two-stage process, as described, for example, in DE-A 24 27 960, example 3 on columns 9 to 10. A small-sized graft polymer is first prepared in the usual way by emulsion polymerization, after which the polymer obtained is agglomerated into particles of larger diameter by adding an agglomeration agent.

Some preferred graft polymers B) are listed below, the particle diameter being the weight average dso.

B / l: 60% by weight of a graft core bl) from bll) 98% by weight n-butyl acrylate bl2) 2% by weight dihydrodicyclopentadienyl acrylate

40% by weight of a graft shell b2) from b21) 75% by weight of styrene b22) 25% by weight of acrylonitrile particle diameter about 200 nm

B / 2: 60% by weight of a graft core bl) as in B / l

40% by weight of a graft shell b2) as in B / l

Particle diameter about 400 nm

B / 3: 60% by weight of a graft core b1) as for B / l

15% by weight of a first graft shell b2) made of styrene

25% by weight of a second graft shell b2) as in B / l

Particle diameter about 500 nm

To the extent that non-grafted polymers are formed from the monomers b2) during grafting, these amounts, which are generally below 10% by weight of b2), are assigned to the mass of component B).

Component B) is rubber-elastic and serves to toughen the hard matrix polymer A). For example, the matrix A) consists of a polymer based on styrene / acrylonitrile, so-called SAN polymer (preferred component A / 3) and the graft polymer B) consists of an alkyl acrylate graft core bl) and a graft shell b2) based on styrene / Acrylonitrile, so you get the molding compositions known to the person skilled in the art as ASA (acrylonitrile / styrene / acrylic ester).

In addition to components A) and B), the thermoplastic molding compositions from which the moldings according to the invention are made can also contain conventional additives such as lubricants and mold release agents, waxes, pigments, dyes, flame retardants, antioxidants, light stabilizers, fibrous and powdery fillers. and reinforcing agents and antistatic agents in the amounts customary for these agents. As a rule, the proportion of the total additives is 0.1 to 20% by weight, preferably 0.5 to 15% by weight, based on the sum of components A) and B).

The dyes and / or pigments used to color the molded parts are known to the person skilled in the art. Examples of common pigments or dyes are titanium dioxide, chalk, carbon black, pigment yellow 164 (CI. 77899), pigment brown 29 (CI. 77500), pigment brown 24 (CI. 77310).

So-called UV stabilizers can be used to stabilize the molded parts against exposure to light, for example substituted resorcinols, salicylates, benzotriazoles, benzophenones and HALS (hindered amine light stabilizers) and the like. They are commercially available, for example, under the trade names Topanol ^® , Irganox ^® and Tinuvin ^® .

The proportion of dyes and / or pigments is usually 0.01 to 15, preferably 0.1 to 10% by weight, and the proportion of stabilizers against exposure to light is 0.1 to 5, particularly 0.2 to 1% by weight. -%, each based on the mixture of A) and B).

The molding compositions can be produced by mixing processes known per se, for example by incorporating the graft polymer B) into the thermoplastic polymer A) at temperatures above the melting point of A), in particular at temperatures from 150 to 350 ° C. in an extruder, Banbury mixer, kneader, roller mill or calender. However, the components can also be mixed "cold" without melting, and the powdery or granular mixture is only melted and homogenized during processing.

The molding compositions are processed into the moldings according to the invention by the generally customary processes. Examples include extrusion (for pipes, profiles, fibers, foils and sheets) and injection molding (for molded parts of all kinds, especially also) those with complicated geometries), as well as calendering and rolling (for plates and film).

The molded parts produced from the molding compositions described are particularly suitable for use outdoors, especially in the construction sector, and there in particular as visual and weather protection parts.

Examples of such molded parts are roller shutters, blinds, panels, canopies, rain gutters, sun protection slats, and similar components.

The molded parts according to the invention have good weather resistance, good impact resistance, permanent coloration, high surface gloss and good heat resistance. They are light in weight, can be easily injection molded, and have good recycling properties.

Examples

The average particle size d is the weight average of the particle size, as determined by means of an analytical ultracentrifuge according to the method of W. Scholtan and H. Lange, Kolloid-Z. and Z. Polymers 250 (1972) pages 782 to 796. The ultracentrifuge measurement 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 dio value indicates the particle diameter at which 10% by weight of all particles have a smaller and 90% by weight a larger diameter. Conversely, for the dg ₀ value it applies that 90% by weight of all particles have a smaller and 10% by weight larger diameter than the diameter which corresponds to the d ₉₀ " ^value . The weight-average particle diameter dso or volume-average particle diameter D ₅ 0 indicates the particle diameter in which 50% by weight or vol.% Of all particles have a larger and 50 wt.% Or vol.% Have a smaller particle diameter. D ₀ -, ds ₀ - and d ₉ o value charakteri¬ Sieren the width Q of the particle size distribution, wherein Q = (dgo-dio) / dso. the smaller Q, the narrower the distribution.

The following components were produced (all% figures are% by weight). Preparation of component A): copolymer of styrene and acrylonitrile

A copolymer of 65% by weight of styrene and 35% by weight of acrylonitrile (for component Al) or of 70% by weight of α-methylstyrene and 30% by weight of acrylonitrile (for component A-2 ) prepared by the process of continuous solution polymerization, as described in the plastics manual, ed. R. Vieweg and G. Daumiller, vol. V "Polystyrol", Carl-Hanser-Verlag Munich 1969, pages 122 to 124. The viscosity number VZ (determined according to DIN 53 726 at 25 ° C., 0.5% by weight in dimethylformamide) was 80 ml / g for component A-1 and 58 ml / g for component A-2.

Production of a component B-1: Particulate graft polymer of small diameter from crosslinked! Poly-n-butyl acrylate (core) / styrene-acrylonitrile copolymer (shell)

To prepare a seed latex, 16 g of butyl acrylate and 0.4 g of tricyclodecenylsylate in 150 g of water were added with the addition of 1 g of the sodium salt. C ₂ -C ₈ paraffin sulfonic acid, 0.3 g potassium persulfate, 0.3 g sodium hydrogen carbonate and 0.15 g sodium pyrophosphate heated to 60 ° C with stirring. 10 minutes after the start of the polymerization reaction, a mixture of 82 g of butyl acrylate and 1.6 g of tricyclodecenyl acrylate was added over the course of 3 hours. After the monomer addition had ended, the mixture was left to react for an hour. The latex obtained had a solids content of 40% and an average particle size dso of 76 nm. The particle size distribution was narrow (quotient Q = 0.29).

150 g of the polybutyl acrylate latex obtained were mixed with 40 g of a mixture of styrene and acrylonitrile (weight ratio 75:25) and 60 g of water and with stirring after the addition of a further 0.03 g of potassium persulfate and 0.05 g of laroyl peroxide for 4 hours heated to 65 ° C. After the graft copolymerization had ended, the polymerization product was precipitated from the dispersion by means of calcium chloride solution at 95 ° C., washed with water and dried in a warm air stream. The degree of grafting of the graft copolymer was 35%.

Production of a component B-2:

Particulate graft polymer of large diameter made of cross-linked! Poly-n-butyl acrylate (core) / styrene-acrylonitrile copolymer (shell). To a mixture of 5 g of the seed latex described under B1,

100 g of water and 0.2 g of potassium persulfate were removed in the course of

3 hours at 60 ° C a mixture of 98 g of n-butyl acrylate and 2 g

Dihydrodicyclopentadienyl acrylate and separately a solution of 1 g Na -C ₂ -C ₁ β-paraffin sulfonate in 50 g water. The

Polymerization was then continued for 2 hours. The average particle diameter dso of the resulting latex was

288 nm with narrow distribution of particle size (Q = 0.1), the

Solids content of the latex was 40%.

150 g of this latex were mixed with 40 g of a mixture of styrene and acrylonitrile (weight ratio 75:25) and 110 g of water and heated with stirring after the addition of a further 0.03 g of potassium persulfate and 0.05 g of lauroyl peroxide to 65 ° C. for 4 hours . The polymerization product obtained in the graft copolymerization was then precipitated from the dispersion using a calcium chloride solution at 95 ° C., separated off, washed with water and dried in a warm air stream. The degree of grafting of the graft copolymer was determined to be 27%.

Production of a component B-3:

Particulate graft polymer of large diameter made of cross-linked! Poly-n-butyl acylate (core) / polystyrene (shell) / styrene-acrylonitrile copolymer (shell).

A mixture of 98 g of n-butyl acrylate and 2 g of dihydrodicyclopentadienyl acrylate and, separately, a solution of 1 were added to a mixture of 3 g of the seed latex described under B1, 100 g of water and 0.2 g of potassium persulfate in the course of 4 hours at 60 ° C g Na -C ₂ -C ₁₈ -paraffin sulfonate in 50 g of water. The polymerization was then continued for 2 hours. The average particle diameter dso of the resulting latex was 430 nm with a narrow distribution of the particle size (Q = 0.1), the solids content was 40%.

150 g of this latex were mixed with 60 g of water, 0.03 g of potassium persulfate and 0.05 g of lauroyl peroxide, after which 15 g of styrene were first applied to the latex particles over a period of 3 hours at 65 ° C. and then a mixture was added over a further 4 hours were grafted on from 18.75 g of styrene and 6.25 g of acrylonitrile. The polymer was then precipitated with a calcium chloride solution at 95 ° C., separated off, washed with water and dried in a warm air stream. The degree of grafting of the polymer was 35% and the particles had an average diameter dso of 510 nm. lo

Components B) are accordingly a conventional ASA polymer with different particle sizes.

The polymer A *) used in the comparative examples was a polyvinyl chloride PVC, which is highly impact-modified with polyacrylic ester (Vinidur® SZ 6465, from BASF)

Additives:

The numbers correspond to the abbreviations used in the tables.

The following were used in the ASA molding compounds:

l: diisodecyl phthalate

2: 2- (2H-benzotriazol-2-yl) -4-methylphenol (Tinuvin® P, Ciba-Geigy) 3: bis (2,2,6,6-tetramethyl-4-piperidyl) sebazate ( Tinuvin ^® 770,

Ciba-Geigy)

Pigment White 6 (Kronos 2220, from Kronos) Pigment Red 101 (Bayferrox® 140M, from Bayer) Pigment Black 7 (carbon black Printex® 75, from Degussa) Pigment Brown 24 (Sicotan® yellow K 2111, from BASF)

The following PVC molding compounds were used:

8: Acrylic acid ester-methacrylic acid ester copolymer (Vinuran 3833, from BASF)

9: Pb stabilizer with acrylic flow aid and external and internal flow aids (Bäropan® R 2930 FP1, Bärlocher)

10 organophosphite compound (Bärostab® CWM 201, from Bärlocher) 11 Ca / Zn stabilizer (Bäropan® MC 8222 FP, from Bärlocher) 12 glycerol monofatty acid ester (Cι ₄ -Cι ₈ ) (Bärolub® LCD, from Bärlo¬ cher )

13 hydrocarbon wax (Bärolub® LKO, Bärlocher)

14: chalk (Hydrocarb ^ 95T, Omya)

15: Pigment brown 29 (CI. 77500) (Sicopal® brown K 2795, from BASF) 6: Carbon black (Printex® 75, from Degussa) 7: Pigment yellow 164 (CI. 77899) (Sicotan® brown K 2711,

BASF) 8: Titanium dioxide (Kronos 2220, Kronos) Production of the blends and the shaped bodies:

Components A) and B) were intimately mixed at 280 ° C. in a conventional extruder, type ZSK 30, from Werner and. Pfleiderer, extruded and granulated. The polymer obtained was then intimately mixed with the additives at 280 ° C. in a mixing extruder, type ZSK30 from Werner and Pfleiderer, extruded and granulated. The compositions given in Table 1 were obtained. Press plates of 5 x 4 cm were produced from the granulate.

The mixtures of the comparative examples consisting of PVC were produced by intimately mixing the components shown in Table 2 in a fast-running mixer. The maximum mixing temperature was 220 ° C. The mixtures were then processed further at 180 ° C. on a roller mill to give rolled skins, from which plates of 5 × 4 cm were pressed at 180 ° C.

Table 1: Composition [wt. Parts] of the ASA molding compounds

Table 2: Composition [wt. Parts] of the PVC molding compounds

Examination of the shaped bodies:

The press plates were weathered using one of the following methods.

Method A: Weathering in a Weather-o-Meter device type CI35A from Atlas, according to the SAE 1960 standard: 40 min day, 20 min day with rain, 60 min day, 60 min night; Black panel temperature approx. 70 ° C; Synchronism.

Method B: Weathering in the Xenotest device type 1200 CPS from Heraeus, according to DIN 53387: 102 min dry, 18 min moist; Blackboard temperature 65 ° C; Synchronism.

To assess the color stability during weathering, the panels were assessed visually before weathering, weathered for 500 h using Method A or B and again assessed visually. In Tab. 3 + means no or little color change, o means moderate, - means strong and - very strong color change, each based on the condition before weathering. In order to assess the surface gloss after weathering, the panels were subjected to a gloss measurement before and after 500 hours of weathering. A Byk-Gardner device and a measuring angle of 60 ° C. were used. Tab. 3 shows the gloss after weathering in%, based on the gloss of the panel before weathering (= 100%).

The stability against graying and chalking was determined as follows: after visual assessment, the plates were weathered for 200 h using method A or B, and then in a 85 ° C. hot aqueous detergent solution ("dishwashing and universal cleaning agent "from the company Chemie-Vertrieb, Hanover) with a concentration of 0.2% by volume. After rinsing with distilled water and drying in an air stream, the plates were visually assessed again. In Table 3 + means no or little graying / chalking, - means strong graying / chalking, in each case related to the condition before weathering and contact with soap solution.

The heat resistance was determined as Vicat softening temperature (ISO 306) using measurement method B.

Tab. 3 summarizes the test results.

vo

Table 3: Results -4

to

π

H

*) before weathering b »vo

The table shows that the molded parts made of ASA according to the invention have significantly better color stability when weathered and a more stable surface gloss than PVC molded parts.

Especially when comparing identical colors,

white: attempts 1 and 3 vs. Trial 3V, brown: Trial 2 vs. Trial 2V, dark brown: Trials 4 and 5 vs. Experiment IV, gray: Experiment 6 vs. Trial 4V

the better weather resistance of the molded parts according to the invention made of ASA is shown.

The resistance to weathering (stability against graying / chalking) of the ASA molded parts, in particular also in the case of dark colors, is higher than that of molded parts made of PVC, as the behavior against detergent solution shows.

Finally, molded parts according to the invention made of ASA are better heat-resistant and lighter than those made of PVC.

Claims

claims

1. Molded parts, made of thermoplastic molding compounds, which contain marriage

al) 50 to 100% by weight of a styrene compound of the general formula

R2

in which R ¹ and R ^{2 are} hydrogen or C 1 -C ₈ -alkyl,

or

one (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the (C 1 -C 6 -alkyl) ester of acrylic acid or methacrylic acid,

a3) 0 to 40% by weight of one or more further monoethylenically unsaturated, different from a2)

Monomers,

B) 1 to 70% by weight, based on the total weight of the molding composition, of a graft polymer based on B),

bl) 30 to 90% by weight of a rubber-elastic graft core made of a polymer with a glass transition temperature below 0 ° C., obtainable by copolymerization of, based on bl), bll) 50 to 99.99% by weight of a (-CC-alkyl) ester of acrylic acid,

bl2) 0.01 to 10% by weight of a polyfunctional, crosslinking monomer, and

b2) 10 to 70% by weight of a graft shell, based on b2),

b21) 50 to 100% by weight of a styrene compound of the general formula

R ²

in which R ⁱ and R ^{2 are} hydrogen or -CC ₈ alkyl,

or

one (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the

(Ci-Cβ-alkyl) esters of acrylic acid or methacrylic acid,

2. Molded parts, produced from thermoplastic molding compositions according to claim 1, in which the thermoplastic polymer A) from, based on A),

al) 50 to 80% by weight of styrene or α-methylstyrene or mixtures thereof, a2) 20 to 40% by weight of acrylonitrile, and

a3) 0 to 20% by weight of one or more further monoethylenically unsaturated monomers

consists.

3. Molded parts produced from thermoplastic molding compositions according to claims 1 or 2, in which the graft polymer B) consists of, based on B),

bl) 30 to 90% by weight of a rubber-elastic graft core made of a polymer with a glass transition temperature below -20 ° C., obtainable by copolymerization of, based on bl),

bll) 80 to 99.9% by weight of n-butyl acrylate or ethylhexyl acrylate or mixtures thereof,

bl2) 0.1 to 4% by weight of dihydrodicyclopentadienyl acrylate,

bl3) 0 to 10% by weight of one or more further monoethylenically unsaturated monomers which are different from bll), and

b2) 10 to 70% by weight of a graft shell, based on b2),

b21) 50 to 80% by weight, styrene or α-methylstyrene or mixtures thereof,

b22) 20 to 40% by weight of acrylonitrile,

b23) 0 to 20% by weight of one or more further ethylenically unsaturated monomers,

or

b24) 80 to 100% by weight, methyl methacrylate,

b25) 0 to 20% by weight of one or more further monoethylenically unsaturated monomers.

4. Molded parts produced from thermoplastic molding compositions according to claims 1 to 3, in which the molding compositions contain customary additives.

5. Molded parts made from thermoplastic molding compounds

Claim 4, in which pigments or dyes or their

Mixtures are included as additives.

6. Molded parts produced from thermoplastic molding compositions according to claim 4, in which stabilizers against the action of light are included as additives.

7. Use of molded parts according to claims 1 to 6 as visual and weather protection parts in the construction sector.