HK1067653B - Thermoplastic compositions providing matt surface appearance - Google Patents

Description

Thermoplastic composition providing a matte surface

Technical Field

The present invention relates to a thermoplastic composition comprising a grafted acrylate rubber, more specifically the present invention relates to a composition suitable for the manufacture of molded articles having a matte surface.

Disclosure of Invention

Low gloss thermoplastic compositions suitable for use in making low gloss articles and methods for making the same are disclosed. The composition comprises a resinous component comprising (a) a (co) polyalkyl (meth) acrylate rubber characterized in that it is free of grafted phases, (b) a poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubber, and (c) a poly (vinyl aromatic-co-nitrile), and a gloss reducing agent that is the reaction product of (d) a compound having two or more maleic anhydride groups per molecule and (e) a compound having two or more terminal primary amine groups per molecule, with the proviso that the sum of the maleic anhydride groups per molecule and the terminal primary amine functional groups per molecule is greater than 4. The gloss reducing agent described above may be incorporated into the composition of the present invention by mixing the reaction product, or alternatively, by mixing the reactants (d) and (e) in the molten resinous component under processing conditions designed to produce the gloss reducing agent of the present invention in situ.

The invention provides the following technical scheme.

1. A thermoplastic molding composition comprising

(I) A resinous component comprising

(a) (co) polyalkyl (meth) acrylate rubber, characterized in that it contains no graft phase,

(b) a poly (vinyl aromatic-co-nitrilamine branched (co) polyalkyl (meth) acrylate rubber, and

(c) poly (vinyl aromatic-co-nitrile), and

(II) a matting agent which is the reaction product of

(d) A compound having two or more maleic anhydride groups per molecule, and

(e) a compound having two or more terminal primary amine groups per molecule, provided that the sum of the maleic anhydride groups per molecule and the terminal primary amine functional groups per molecule is greater than 4, wherein the (co) polyalkyl (meth) acrylate rubber is present in the composition in an amount of 10 to 40% relative to the weight of the resinous component (I), and wherein the amounts of (a) and (b) are related by weight such that the ratio of (a) to the sum of (a) + (b) is 0.1 to 0.8.

2. The composition of claim 1, wherein the (co) polyalkyl (meth) acrylate rubber is present in the composition in an amount of 15 to 35% relative to the weight of resinous component (I).

3. The composition of claim 1 wherein the amounts of (a) and (b) are related by weight such that the ratio of (a) to the sum of (a) + (b) is from 0.15 to 0.7.

4. The composition of claim 1, wherein the particle size (weight average particle size) of the (co) polyalkyl (meth) acrylate rubber is 0.02 to 10 microns.

5. The composition of claim 1, wherein the particle size (weight average particle size) of the (co) polyalkyl (meth) acrylate rubber is 0.03 to 1 μm.

6. The composition of claim 1, wherein (a) is crosslinked.

7. The composition of claim 1, wherein (a) comprises (co) polymerized acrylic acid C₁-C₁₈An alkyl ester.

8. The composition of claim 1, wherein (a) comprises (co) polymerized methacrylic acid C₁-C₆An alkyl ester.

9. The composition of claim 1, wherein (a) is a member selected from the group consisting of poly (n-butyl acrylate), poly (ethyl acrylate), and poly (2-ethylhexyl acrylate).

10. The composition of claim 7, wherein (a) further comprises from 1 to 20 wt%, relative to the weight of (a), of at least one (co) polymerized unit derived from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, and vinyl toluene.

11. The composition of claim 8, wherein (a) further comprises from 1 to 20 wt%, relative to the weight of (a), of at least one (co) polymerized unit derived from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, and vinyl toluene.

12. The thermoplastic molding composition of claim 1 wherein the poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubber is crosslinked.

13. The thermoplastic molding composition of claim 12 wherein the poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubber comprises a polyalkyl (meth) acrylate matrix.

14. The thermoplastic molding composition of claim 13 wherein the matrix is copolymerized.

15. The thermoplastic molding composition of claim 13 wherein the matrix is homopolymerized.

16. The thermoplastic molding composition of claim 12 wherein the poly (vinyl aromatic-co-nitrile) is a styrene-acrylonitrile copolymer.

17. The thermoplastic molding composition of claim 1 wherein (c) is styrene-acrylonitrile having a weight average molecular weight of 50,000 to 200,000 gm/mole.

18. The thermoplastic molding composition of claim 1 wherein resinous component (I) is present in an amount of 80 to less than 99% relative to the weight of the composition.

Background

Products made from thermoplastic molding compositions are often gloss-multiplied, however for some applications this is an undesirable property. There is a great demand for low gloss compositions, particularly in applications such as computer housings, keyboards, household appliances and automotive parts.

Acrylonitrile-styrene-acrylate interpolymers (hereinafter referred to as "ASA resins") are well known in the art and have many desirable characteristics such as good strength and excellent weatherability. Attempts have been made to reduce the high gloss of these resins, but suffer from the disadvantages described below.

The removal of gloss by surface embossing has been used in practice but requires a separate step and increases costs. Moreover, subsequent abrasion can remove the embossed matte surface and can cause gloss reproduction. The addition of finely divided fillers, such as silica, silicates or aluminates or other similar inert minerals, has proven to reduce the gloss of thermoplastic molding compositions, which is often accompanied, however, by an undesirable reduction in the level of physical and/or mechanical properties of at least some of the molded articles, most notably impact strength. In addition to the adverse effect on impact resistance, there is often a corresponding decrease in the heat distortion temperature, a decrease in weld line strength, inadequate weathering and light stability, and a decrease in other important properties.

U.S. Pat. No. 4,460,742 discloses a matte thermoplastic resin composition comprising a thermoplastic resin such as acrylic resin and a component containing methacrylic acid C_1-4Alkyl esters and aromatic vinyl with acrylic acid C_1-13A crosslinked polymerization product of an alkyl ester copolymer.

U.S. Pat. No. 4,894,416 discloses a low gloss thermoplastic blend with good physical properties comprising a core-shell ASA (acrylate-styrene-acrylonitrile interpolymer) resin blended with a glycidyl (meth) acrylate polymer.

U.S. Pat. No. 5,580,924 discloses a delustered thermoplastic composition which entails combining a styrene-acrylonitrile copolymer (SAN) and an acid in the presence of an electrophile to form a gel and then compounding the resulting gel with polycarbonate, SAN and ABS graft polymer to form a delustered PC/ABS/SAN composition.

U.S. Pat. No. 5,990,239 discloses a low gloss thermoplastic blend comprising an ASA resin blended with a polyalkylacrylate rubber that does not contain a grafted phase.

Detailed Description

The thermoplastic composition of the present invention comprises

(I) A resinous component comprising:

(a) ungrafted (co) polyalkyl (meth) acrylate rubber, preferably polybutyl (meth) acrylate rubber, which may optionally be crosslinked,

(b) grafted rubbers, which may optionally be crosslinked, comprising a poly (meth) acrylic acid alkyl ester matrix, preferably poly (meth) butyl acrylate, and a phase grafted thereto (herein grafted phase), wherein the matrix may be homopolymeric or copolymeric, and wherein the grafted phase comprises a poly (vinyl aromatic-co-nitrile), preferably styrene-acrylonitrile (SAN), and

(c) a poly (vinyl aromatic-co-nitrile), preferably styrene-acrylonitrile (SAN), having a weight average molecular weight of approximately 50000 to 200000 g/mol, preferably 80000 to 150000 g/mol, and

(II) a matting agent which is the reaction product of:

(d) a compound having two or more maleic anhydride groups per molecule, and

(e) a compound having two or more terminal primary amine groups per molecule.

In a preferred embodiment, the composition according to the invention is further characterized in that the content of (co) polyalkyl (meth) acrylate rubber is 10 to 40, preferably 15 to 35% relative to the weight of the resinous component. In a still further preferred embodiment, the components (a) and (b) are in a weight relationship such that the ratio of (a) to the sum of (a) + (b) is from 0.1 to 0.8, preferably from 0.15 to 0.7. In a still further preferred embodiment, the particle size (weight average particle size) of the acrylate rubber is from 0.02 to 10 microns, preferably from 0.03 to 1 micron.

The ungrafted rubber, i.e. (a) of the resinous component, which is a (co) polyalkyl (meth) acrylate rubber, which may optionally be crosslinked, is the polymerization product of known (co) monomers including C acrylic acid_1-18Alkyl esters and methacrylic acid C_1-6Alkyl esters, preferably acrylic acid C with or without additional comonomers_2-8Alkyl esters and methacrylic acid C_1-4An alkyl ester. Most preferred are poly (n-butyl acrylate), poly (ethyl acrylate) and poly (2-ethylhexyl acrylate). Optionally, the rubber may contain minor amounts, from about 1 to 20 wt%, relative to the weight of the (meth) acrylate monomer, of additional monomers such as styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, vinyl toluene, or other ethylenically unsaturated comonomers copolymerizable with the (meth) acrylate monomer.

Crosslinking, which is an optional characteristic of rubbers useful in the present context, results in the rubber being substantially insoluble in solvents such as tetrahydrofuran, methyl ethyl ketone, cyclohexanone, or acetone. The degree of crosslinking imparted to the rubber is that which results from the incorporation of about 0.1 to 2.0 parts by weight (pbw) of a crosslinking agent per hundred parts by weight rubber (pphr), preferably the crosslinking agent is present in an amount of 0.4 to 1.4 pphr. Crosslinking of the copolymer matrix may be carried out during the polymerization of the rubber, including during the reaction, with crosslinking agents such as di-or poly-functional ethylenically unsaturated monomers. Among the suitable crosslinking agents, mention may be made of divinylbenzene, trimethylolpropane triacrylate, allyl methacrylate, diallyl fumarate, diallyl maleate, 1, 3-butene dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, methylene bisacrylamide, diethylene glycol diacrylate, ethylene glycol diacrylate, divinyl ether, diallyl phthalate, divinyl sulfone, divinyl sorbitol, triethylene glycol dimethacrylate, propylene glycol diacrylate, butylene glycol diacrylate, octanediol diacrylate, trimethylolpropane triacrylate, tetraacrylate of pentaerythritol, ethylidene norbornene, vinyl norbornene, diallyl phosphonate, triallyl cyanurate and triallyl isocyanurate. A preferred crosslinking agent is diallyl maleate (DAM).

The ungrafted polyalkylacrylate rubber has a weight average particle size of 0.02 to 10 microns, preferably 0.03 to 1 micron.

The grafted rubber, i.e. (b) of the resinous component, comprises an optionally crosslinked (co) polyalkyl (meth) acrylate matrix and a phase grafted thereto (herein "grafted phase"). The matrix may be homopolymeric or copolymeric and the grafted phase may comprise poly (vinyl aromatic-co-nitrile), preferably styrene-acrylonitrile (SAN).

The matrix is in all respects identical to the ASA resin of component (a) described above and, like (a), it is optionally crosslinked. The optionally crosslinked grafted phase comprises a poly (vinyl aromatic-co-nitrile), preferably a styrene-acrylonitrile copolymer (SAN). The grafted phase preferably comprises about 20 to 40% of a nitrile copolymer (e.g., acrylonitrile, referred to herein as "AN") and 80 to 60% of a vinyl aromatic comonomer (e.g., styrene, referred to herein as "S"). Preferred relative amounts are 25 to 35% of the former and 65 to 75% of the latter, the percentages being related to the weight of the grafted phase. Optionally, the grafted phase may comprise minor amounts, less than 20% by weight relative to the weight of the phase, of at least one ingredient selected from additional monomers such as substituted chlorobenzenes, styrenes (t-butylstyrene, alpha-methylstyrene), ethylenically unsaturated compounds (methyl methacrylate, alkyl acrylates, vinylidene chloride, maleic anhydride, N-substituted maleimides), ethylene, propylene and isobutylene.

The molecular weight of the grafted phase may optionally be controlled by the use of conventional chain transfer agents. Suitable chain transfer agents include tertiary dodecyl mercaptan, n-dodecyl mercaptan, terpenes, terpinolenes and chlorinated hydrocarbons.

The grafted phase may optionally be crosslinked. Crosslinking is carried out in a manner similar to that described above for the matrix. The amount of crosslinking agent which may be incorporated into the graft phase is about 0.05 to 0.5, preferably 0.1 to 0.3pphr of the graft phase.

The preferred composition of the graft phase is a SAN copolymer comprising 28% AN and 72% styrene. Crosslinking is accomplished by the addition of DAM.

The weight ratio of graft phase to substrate in component (b) is from about 25 to 150pbw graft phase per 100pbw substrate.

The grafted copolymer rubber has a weight average particle size of 0.02 to 10 microns, preferably 0.03 to 1 micron.

The grafted copolymer rubbers of the present invention are prepared by any method known to those skilled in the art. Preferably, they are prepared by polymerizing styrene and acrylonitrile monomers in the presence of rubber by emulsion, suspension or bulk polymerization methods.

A portion of the vinyl aromatic and unsaturated nitrile monomers polymerized in the presence of the rubber matrix used to prepare the grafted copolymer rubber of the present invention will not be grafted to the rubber matrix but will be present as ungrafted polymer, such as polystyrene-acrylonitrile (SAN). The amount of such ungrafted SAN polymer depends on the weight ratio of monomer to rubber, the nature of the rubber, and the polymerization conditions. The ungrafted fraction, preferably SAN, has a number average molecular weight of about 20000 to 100000 g/mol, preferably 25000 to 75000 g/mol.

Component (c) is ungrafted, uncrosslinked poly (vinyl aromatic-co-nitrile), preferably styrene-acrylonitrile. The component is characterized in that it comprises about 20 to 40% of structural units derived from a nitrile comonomer (preferably acrylonitrile) and 80 to 60% of an aromatic vinyl comonomer (preferably styrene); preferred amounts are 25 to 35% of nitrile comonomer and 65 to 75% of aromatic vinyl comonomer, the percentages relating to the weight of the poly (vinyl aromatic-co-nitrile). Optionally, the phase may comprise minor amounts, less than 20 wt% relative to the weight of the phase, of additional monomers such as substituted styrene (t-butylstyrene, chlorobenzene, alpha-methylstyrene) or ethylenically unsaturated compounds such as methyl methacrylate, alkyl acrylates, vinylidene chloride, ethylene, propylene, isobutylene, maleic anhydride, N-substituted maleimide or mixtures of any of the above. A preferred composition of uncrosslinked component (c) comprises 32% AN and 68% styrene. The copolymer is further characterized in that it has a weight average molecular weight of about 50000 to 200000 g/mol, preferably 70000 to 160000 g/mol.

Preferably, the resinous component (I) of the present invention, i.e. the combination of (a), (b) and (c), is present in the composition in an amount of at least 80% and less than 99%, preferably from 82 to 98%, most preferably from 85 to 95%, relative to the weight of the composition, while the gloss reducing agent is present in an amount of more than 1% and up to 20%, preferably from 2 to 18%, most preferably from 5 to 15%, the percentages being relative to the weight of the composition (total weight of resinous component and gloss reducing agent).

It has been found that the composition provides substantial reduction in gloss while maintaining desirable physical properties such as impact strength, tensile strength, and good thermal properties.

The delustering agent of the invention is a reaction product of the following substances:

(d) compounds having two or more maleic anhydride groups per molecule and

(e) compounds with two or more terminal primary amine groups per molecule (average amine functionality greater than 1.8 per molecule).

The gloss reducing agent may be incorporated into the composition as a pre-formed reaction product of (d) and (e), or may be added to the ASA melt as a separate reactant in its pre-reacted form. In the latter case, the reaction product is formed under the influence of heat during melt blending, for example during extrusion to form the low gloss composition of the present invention.

Maleic anhydride compounds suitable for the present context are compounds (optionally oligomeric compounds) having a weight average molecular weight of at least 4000 g/mol, which contain at least 2 maleic anhydride functional groups per molecule and comprise in their molecule structural units derived from (i) at least one vinyl monomer free of maleic anhydride functionality and (ii) at least one maleic anhydride functional group.

Suitable maleic anhydride compounds have a preferred molecular weight (weight average molecular weight) of 50000 to about 200000, most preferably 80000 to 150000 g/mol. The compound contains at least 2 maleic anhydride functional groups per molecule, preferably from 2 to 400, most preferably from 5 to 300 maleic anhydride functional groups per molecule.

Among the suitable vinyl monomers of zero maleic anhydride functionality, mention may be made of ethylene, propylene, styrene, acrylonitrile, (meth) acrylates and vinyl acetate.

Preferred maleic anhydride compounds are styrene-methyl methacrylate-maleic anhydride and styrene-maleic anhydride copolymers.

Suitable amine compounds contain polyolefin or polyether structural units and contain at least two terminal primary amine functional groups per molecule. Preferred structures comprise at least one of polyethylene, polypropylene and polyether structural units, most preferably polypropylene oxide structural units. Suitable amine compounds typically have a number average molecular weight of from 300 to 18000, preferably from 400 to 15000, most preferably from 700 to 10000, and the compounds contain at least 2 (average amine functionality greater than 1.8), preferably from 2 to 5, most preferably from 3 to 4 terminal primary amine functional groups per molecule. The most preferred amine compound is polypropylene oxide having a molecular weight of 4000 to 6000 and containing 3 terminal primary amine functional groups per molecule.

Importantly, the total number of maleic anhydride groups in the maleic anhydride compound and primary amine terminal functional groups in the amine compound is greater than 4.

The gloss reducing agents are prepared by reacting (d) with (e) and are conventional and can be carried out according to procedures and manners well known to those skilled in the art.

The gloss reducing agent may also be incorporated into the composition of the present invention as pre-reacted components (d) and (e). In this embodiment of the invention, the maleic anhydride compound and the amine compound are mixed together with a sufficient amount of ASA resin to produce a reaction product under thermoplastic processing conditions.

An effective amount of gloss reducing agent is generally greater than 1 and up to 20%, preferably from 2 to 18%, most preferably from 5 to 15% by weight of the composition (total weight of resinous components and gloss reducing agent). Smaller amounts give insufficient matting properties, larger amounts are too expensive and may adversely affect the physical properties of the mixture or of molded articles made therefrom.

The compositions of the present invention may be modified by the addition of additives which take advantage of their art-recognized function. These additives include fillers (e.g., clay and talc), reinforcing agents (e.g., glass fibers), impact modifiers, other resins, plasticizers, flow promoters and other processing aids, stabilizers, colorants, mold release agents, flame retardants, uv screeners, and the like.

The compositions of the present invention may be prepared by mixing the resinous component with a previously prepared reaction product, or alternatively, with a previously reacted reactant capable of reacting to form a gloss reducing agent during thermoplastic processing of the composition. In any of the embodiments of the present invention, the mixing may be carried out by conventional means and the following steps well known to those skilled in the art. Mixing or kneading may be carried out with a machine such as a Banbury mixer or an extruder, or by solvent blending. The order of addition is not critical but the components should be thoroughly mixed together and subjected to time and temperature conditions that will assist in completion of the reaction.

The invention will be better understood by reference to the following examples which are intended for the purpose of illustration and not of limitation, and which set forth the best mode contemplated for carrying out the invention.

Examples

Compositions demonstrating the present invention were prepared and their properties were measured. The terms used in the following description are defined as follows:

melt temperature-the surface temperature of the extruded sheet is measured directly (using an IR-meter) as it emerges from the die.

Extrusion pressure-on-line pressure measurement near the end of the extruder barrel;

MFI-melt flow index, in g/10 min, measured according to ASTM D1238, at 230 ℃ under a load of 10 kg;

viscosity-Kayeness capillary rheometer was used to evaluate viscosity, measured at 100l/s at 220 ℃ according to ASTM D3835;

the gloss (85 °) of the extruded sheet was measured at room temperature using a Gardner gloss meter according to the procedure set forth in ASTM D523, both in the direction perpendicular to the flow direction and in the direction parallel to the flow direction.

In practicing the following examples, the compositions contain, in addition to the components described, minor amounts of the following conventional additives (which are believed to be not critical to the invention): antioxidants, UV absorbers, plasticizers, flow aids, lubricants, and pigments.

The preparation of the compositions described below followed conventional procedures. U.S. Pat. No. 5,990,239, which is incorporated herein by reference, discloses the preparation of low gloss compositions comprising ASA resin blended with a polyalkylacrylate rubber which is free of grafted phases.

The following symbols appearing in the table are described below:

a-1: SAN grafted crosslinked poly (butyl acrylate-acrylonitrile) rubber; the rubber had a monomodal particle size distribution with an average particle size of 0.15 microns. The weight ratio between rubber and grafted SAN was 100: 60. The weight ratio of styrene to acrylonitrile was about 70/30. A-1 contained about 12% SAN (acrylonitrile content of SAN 23% and its molecular weight (number average) of 47000 gm/mole). The rubber content of A-1 was about 55%.

A-2: this is a mixture of two different SAN grafted butyl acrylate rubbers having bimodal particle size distributions of 0.4 and 0.15 microns. The core/shell structure of the rubber (styrene core and crosslinked poly (butyl acrylate) shell) is believed to be unimportant to the findings of the present invention. The weight ratio between rubber and grafted SAN was approximately 100: 80. The weight ratio of styrene to acrylonitrile was about 70/30. The rubber content was about 55 wt%.

A-3: a mixture of 44% SAN-grafted acrylate rubber (weight ratio between rubber and grafted SAN of approximately 100: 60), 27.5% ungrafted acrylate rubber and 28.5% SAN (23% AN, number average molecular weight 47000 g/mole). The particle size of the rubber was 0.15 microns and the rubber content was 55%. (the rubber in the grafted part (a) and ungrafted part (b) was butyl acrylate with 6 wt% acrylonitrile).

The compositions of A-1, A-2 and A-3 are shown in Table 1 below:

TABLE 1

Components	A-1	A-2	A-3
				Ungrafted polyacrylate rubber	0.0％	0.0％	27.5％
SAN grafted polyacrylate rubber	88.0％	100.0％	44.0％
				SAN	12.0％	0.0％	28.5％

The compositions listed below each contained 45.5% of the "a" component (see table 1) and 54.5% SAN, the percentages being relative to the total weight of the listed compositions. The weight average molecular weight and acrylonitrile content of SAN were 120,000g/mole and 32%, respectively. The rubber content of each composition shown in Table 2 was 25% by weight.

TABLE 2

Resinous component	R-1	R-2	R-3
				Ungrafted polyacrylate rubber	0.0％	0.0％	13％
SAN grafted polyacrylate rubber	40％	46％	20％
				SAN	60％	55％	67％

The gloss reducing agent components used in the exemplified compositions are present in the stated amounts expressed as parts by weight per hundred parts resinous component (pphr).

The maleic anhydride compound was a styrene/methyl methacrylate/maleic anhydride copolymer (components 68/7/25 weight relationship to each other) having a number average molecular weight of 60,000g/mole with about 150 maleic anhydride functional groups per molecule.

The amine compound is a poly (propylene oxide) primary triamine having a molecular weight of about 5000 g/mole.

Compounding of the composition and extrusion of the test samples were carried out according to the procedure outlined below.

Compounding

	American Leistritz 30-mm double-screw extruder
		Melt temperature:	for zones-1 to 10 (die) the settings are: 190 to 230 deg.C
Screw rotation speed:	250rpm

extrusion

An extruder:	killion 1 extruder with 6 "adjustable die
		Melt temperature:	for all zones and dies the settings were: 380 deg.F

Screw rotation speed:	the following are defined: 100rpm
		Traction speed:	2.0 cm/sec

The dimensions of the extruded bars were 8.5 cm wide and 50 mils thick. All samples were left at 23 ℃ and 50% relative humidity for at least 48 hours prior to physical testing.

TABLE 3

	1(C)	2(C)	3(C)	4(C)	5
						Resinous component	R-1	R-3	R-1	R-2	R-3
Maleic anhydride compound, pphr	0	0	5	5	5
						Amine compound, pphr	0	0	8	8	8
Melt temperature of extrusion	432	421	434	430	427
						Extrusion pressure (Psi)	2075	1730	2795	2925	2680
MFI	14.1	14.9	3.5	1.1	3.7
						Viscosity (Pa. s)	1230	1342	1894	2262	1826
Gloss, vertical	82	46	18	35	15
						Gloss, parallel	92	53	17	37	14

(C) Denotes a comparative example

The results shown in Table 3 clearly show that the gloss reducing agent according to the invention of example 5 is very effective in reducing gloss, the resinous component of example 5 comprising components (a), (b) and (c). Comparative examples (comparative examples 1 and 3) in which the resinous component contained only component (a) and comparative example 4 in which the resinous component did not contain component (b) showed a moderate reduction in gloss.

Example 2

In another set of examples, compositions as described below were prepared and their properties were measured.

TABLE 4

	6(C)	7
			Resinous component	R-2	R-3
Maleic anhydride compound, pphr	5	5
			Amine compound, pphr	4	4
Melt temperature of extrusion,. Fahrenheit	432	427
			Extrusion pressure (Psi)	2855	2395

MFI	0.4	5.1
			Viscosity (Pa. s)	2351	1711
Gloss, vertical	43	39
			Gloss, parallel	48	37

(C) Represents a comparative example

In the context of the resinous component designated R-3, the results relate to the efficacy of the gloss reducing agent, and in R-2 the results relate to its lower efficiency.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.

Claims (18)

1. A thermoplastic molding composition comprising

(I) A resinous component comprising

(a) (co) polyalkyl (meth) acrylate rubber, characterized in that it contains no graft phase,

(b) poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubbers, and

(c) poly (vinyl aromatic-co-nitrile), and

(II) a matting agent which is the reaction product of

(d) A compound having two or more maleic anhydride groups per molecule, and

(e) a compound having two or more terminal primary amine groups per molecule, provided that the sum of the maleic anhydride groups per molecule and the terminal primary amine functional groups per molecule is greater than 4, wherein the (co) polyalkyl (meth) acrylate rubber is present in the composition in an amount of 10 to 40% relative to the weight of the resinous component (I), and wherein the amounts of (a) and (b) are related by weight such that the ratio of (a) to the sum of (a) + (b) is 0.1 to 0.8.

2. The composition of claim 1 wherein the (co) polyalkyl (meth) acrylate rubber is present in the composition in an amount of 15 to 35% relative to the weight of resinous component (I).

3. The composition of claim 1, wherein the amounts of (a) and (b) are related by weight such that the ratio of (a) to the sum of (a) + (b) is from 0.15 to 0.7.

4. The composition of claim 1 wherein the particle size (weight average particle size) of the (co) polyalkyl (meth) acrylate rubber is from 0.02 to 10 microns.

5. The composition of claim 1 wherein the particle size (weight average particle size) of the (co) polyalkyl (meth) acrylate rubber is from 0.03 to 1 micron.

6. The composition of claim 1 wherein (a) is crosslinked.

7. The composition of claim 1, wherein (a) comprises (co) polymerized acrylic acid C₁-C₁₈An alkyl ester.

8. The composition of claim 1, wherein (a) comprises (co) polymerized methacrylic acid C₁-C₆An alkyl ester.

9. The composition of claim 1 wherein (a) is a member selected from the group consisting of poly (n-butyl acrylate), poly (ethyl acrylate), and poly (2-ethylhexyl acrylate).

10. The composition of claim 7, wherein (a) further comprises from 1 to 20 wt%, relative to the weight of (a), of at least one (co) polymerized unit derived from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, and vinyl toluene.

11. The composition of claim 8, wherein (a) further comprises from 1 to 20 wt%, relative to the weight of (a), of at least one (co) polymerized unit derived from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, and vinyl toluene.

12. The thermoplastic molding composition of claim 1 wherein the poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubber is crosslinked.

13. The thermoplastic molding composition of claim 12 wherein the poly (vinyl aromatic-co-nitrile) -grafted (co) polyalkyl (meth) acrylate rubber comprises a polyalkyl (meth) acrylate matrix.

14. The thermoplastic molding composition of claim 13 wherein the matrix is copolymerized.

15. The thermoplastic molding composition of claim 13 wherein the matrix is homopolymerized.

16. The thermoplastic molding composition of claim 12 wherein the poly (vinyl aromatic-co-nitrile) is a styrene-acrylonitrile copolymer.

17. The thermoplastic molding composition of claim 1 wherein (c) is styrene-acrylonitrile having a weight average molecular weight of 50,000 to 200,000 gm/mole.

18. The thermoplastic molding composition of claim 1 wherein resinous component (I) is present in an amount of 80 to less than 99% relative to the weight of the composition.