JP2003055522A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition having excellent balance of impact resistance and processability, hardly causing discoloration when used outdoors, and having good retention of luster. SOLUTION: This thermoplastic resin composition comprises (A) 15-80 pts.wt. composite rubber-based graft copolymer obtained by polymerizing 46-80 wt.% aromatic vinyl monomer, 5-24 wt.% vinyl cyanide monomer and 0-30 wt.% alkyl (meth)acrylate monomer on a compounded gummy polymer comprising a polyorganosiloxane component and a polyalkyl (meth)acrylate component, and (B) 20-85 pts.wt. copolymer obtained by polymerizing 10-50 wt.% aromatic vinyl monomer, 0-10 wt.% vinyl cyanide monomer and 50-90 wt.% alkyl (meth) acrylate monomer [the total of the components (A) and (B) is 100 pts.wt].

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having a good balance of impact resistance and workability and good weather resistance.

[0002]

2. Description of the Related Art ABS resin is a resin having a good balance of impact resistance and workability, and is used in a wide range of fields such as interior / exterior parts for vehicles such as automobiles, housings for various home appliances and office automation equipment, and other miscellaneous goods fields. Is used for. However, A
The BS resin has a drawback that it has poor weather resistance due to its rubber component. Therefore, various resins have been proposed in which the rubber component in the ABS resin is replaced with a polyalkyl (meth) acrylate rubber and a composite rubber composed of a polyorganosiloxane component and a polyalkyl (meth) acrylate component. Among them, a graft copolymer using a composite rubber composed of a polyorganosiloxane component excellent in impact resistance and a polyalkyl (meth) acrylate component as a rubber component and a thermoplastic resin composition thereof are disclosed in JP-A-8-41149. Has been proposed to. However, the resin composition described in JP-A-8-41149 uses an acrylonitrile-styrene copolymer as a matrix resin although it has excellent impact resistance and fluidity during melt molding. The weather resistance was not sufficient, and there were drawbacks such as restrictions when used outdoors. Further, although the resin composition described in JP-A-8-283524 has good weather resistance,
Since polymethylmethacrylate resin is used as the matrix resin, it has low fluidity during melt molding, making it difficult to injection-mold large-sized or thin-walled molded products such as automobile parts. There is a problem in that the shape or the processing method is restricted. In addition, the resin composition described in JP-A-11-35782 uses a styrene-methyl methacrylate copolymer as a matrix resin, so there is little discoloration when used outdoors, but gloss when used outdoors. The retention rate is not sufficient, and in particular, black molded products have drawbacks such as poor jetness and low commercial value.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a resin composition comprising a graft copolymer using a composite rubber composed of a polyorganosiloxane component and a polyalkyl (meth) acrylate component and a thermoplastic resin as constituent components. Another object of the present invention is to provide a resin composition which has an excellent balance of impact resistance and processability, has little discoloration during outdoor use, and has a good gloss retention rate.

[0004]

Means for Solving the Problems As a result of extensive studies on the above problems, the present inventors have found that a specific copolymer can be added to a composite rubber graft copolymer having a specific vinyl cyanide monomer content. It has been found that a resin composition having a high fluidity during melt molding, a low discoloration during outdoor use, and a good gloss retention rate can be obtained by blending the above-mentioned compound (1), and thus the present invention has been completed.

That is, the present invention provides a composite rubber-like polymer comprising a polyorganosiloxane component and a polyalkyl (meth) acrylate component, and an aromatic vinyl monomer 4
6-80% by weight, vinyl cyanide-based monomer 5-24% by weight, alkyl (meth) acrylate-based monomer 0-30% by weight, and composite rubber-based graft copolymer (A) 1
5 to 80 parts by weight, aromatic vinyl monomer 10 to 50% by weight, vinyl cyanide monomer 0 to 10% by weight, alkyl (meth) acrylate monomer 50 to 90% by weight are polymerized. The thermoplastic resin composition is characterized by comprising 20 to 85 parts by weight of the copolymer (B) thus obtained [total 100 parts by weight of the components (A) and (B)].

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The organosiloxane used in the polyorganosiloxane component constituting the composite rubber of the composite rubber-based graft copolymer (A) used in the present invention is 3
A dimethyl siloxane-based cyclic body having a member ring or more, 3
A 6-membered ring is preferable. Specific examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc. These may be used alone or in combination of two or more.

If necessary, a siloxane-based crosslinking agent,
A vinyl polymerizable functional group-containing siloxane can be added. The siloxane-based cross-linking agent is trifunctional or tetrafunctional.
Functional silane-based crosslinking agents such as trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, etc. are used.

The vinyl-polymerizable functional group-containing siloxane has a vinyl-polymerizable functional group and can be bonded to dimethylsiloxane through a siloxane bond. Considering the reactivity with dimethylsiloxane, vinyl-polymerizable functional group-containing siloxane is used. Various alkoxysilane compounds containing a polymerizable functional group are preferred. Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, γ
-Methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane and other methacryloyloxysiloxanes, tetramethyltetravinylcyclotetrasiloxane and other vinylsiloxanes, p-vinylphenyldimethoxymethylsilane, and γ-mercaptopropyldimethoxy Examples thereof include mercaptosiloxanes such as methylsilane and γ-mercaptopropyltrimethoxysilane. These vinyl-polymerizable functional group-containing siloxanes can be used alone or as a mixture of two or more kinds.

The polyorganosiloxane component can be produced by adding a dimethylsiloxane cyclic compound or a mixture containing a siloxane crosslinking agent and a vinyl-polymerizable functional group-containing siloxane, if necessary, with an anionic activator, using a homomixer or a super mixer. It is preferably produced by mixing using a sonic mixer and condensing.

As the anionic activator, alkylbenzene sulfonic acid, alkyl sulfuric acid, and / or their sodium salt, potassium salt, and ammonium salt are preferable.
Specifically, dodecylbenzene sulfonic acid, octylbenzene sulfonic acid, octyl sulfate, lauryl sulfate, sodium dodecylbenzene sulfonate,
Examples include sodium octylbenzene sulfonate, sodium octyl sulphate, sodium lauryl sulphate and the like.

The polyalkyl (meth) acrylate component constituting the composite rubber of the composite rubber-based graft copolymer (A) used in the present invention is alkyl (meth)
It is a polymer of an acrylate and a polyfunctional alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and hexyl methacrylate, 2-ethylhexyl methacrylate, and n-lauryl methacrylate. The use of n-butyl acrylate is particularly preferable.

As the polyfunctional alkyl (meth) acrylate, for example, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1 , 4-butylene glycol di (meth) acrylate and the like. The amount of the polyfunctional alkyl (meth) acrylate used is preferably 0.1 to 5% by weight, and more preferably 0.5 to 3% by weight in the alkyl (meth) acrylate component.
Is. The alkyl (meth) acrylate and the polyfunctional alkyl (meth) acrylate may be used alone or in combination of two or more.

The polyalkyl (meth) acrylate component can be produced by sodium hydroxide, potassium hydroxide,
The above-mentioned alkyl (meth) acrylate and polyfunctional alkyl (meth) acrylate are produced by emulsion polymerization using a usual radical initiator into the latex of polyorganosiloxane rubber neutralized by the addition of an aqueous alkaline solution such as sodium carbonate. Preferably.

The polyorganosiloxane component constituting the composite rubber of the composite rubber-based graft copolymer (B) in the present invention is preferably 3 to 20% by weight. When the content of the polyorganosiloxane component is less than 3% by weight, the impact resistance is poor, which is not preferable. On the other hand, if it exceeds 20% by weight, the coagulation recovery of the composite rubber-based graft latex is deteriorated due to the influence of the anion activator in the polyorganosiloxane component. Furthermore, the bronzing phenomenon is likely to occur, which is not preferable.

The weight average particle diameter of the composite rubber is 0.05 to
It is preferably 0.30 μm. If the weight average particle diameter is less than 0.05 μm, it is necessary to use a large amount of anionic activator during the production of the polyorganosiloxane rubber component. As a result, the coagulation recovery of the composite rubber-based graft latex by the salting-out agent is reduced, which is not preferable. On the contrary, 0.30
If it exceeds μm, a bronzing phenomenon occurs, which is not preferable.

Examples of the aromatic vinyl monomer constituting the composite rubber graft copolymer (A) in the present invention include styrene, α-methylstyrene and vinyltoluene. Particularly preferred is styrene. Examples of vinyl cyanide-based monomers include acrylonitrile and methacrylonitrile. Acrylonitrile is particularly preferable. Examples of the alkyl (meth) acrylate-based monomer include methyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate and the like.

The composition ratio of the aromatic vinyl-based monomer (i), the vinyl cyanide-based monomer (ii), and the alkyl (meth) acrylate-based monomer (iii) is (i) 46 to 80% by weight. , (Ii) 5 to 24% by weight, (iii) 0 to 30% by weight, preferably (i) 50 to 80% by weight, (ii) 5
˜20 wt%, (iii) 0-30 wt%. When the aromatic vinyl monomer (i) is less than 46% by weight, the fluidity is poor, and when it exceeds 80% by weight, the impact resistance is poor, which is not preferable. If the vinyl cyanide-based monomer (ii) is less than 5% by weight, the impact resistance is poor, and if it exceeds 24% by weight, the gloss retention rate during outdoor use is lowered, which is not preferable. Further, when the alkyl (meth) acrylate-based monomer (iii) exceeds 30% by weight, impact resistance and fluidity are poor, which is not preferable.

The ratio of the composite rubber constituting the composite rubber graft copolymer (A) used in the present invention is not particularly limited, but it is preferably 15 to 80% by weight.
The graft ratio of the composite rubber graft copolymer (A) is not particularly limited, but is preferably 10 to 150%, and particularly preferably 20 to 100% in view of the balance between moldability and impact resistance.

Examples of the aromatic vinyl type monomer constituting the copolymer (B) in the present invention include styrene, α-methylstyrene, vinyltoluene and the like. Particularly preferred is styrene. Examples of vinyl cyanide-based monomers include acrylonitrile and methacrylonitrile. Acrylonitrile is particularly preferable. Examples of alkyl (meth) acrylate monomers include methyl methacrylate and 2-
Ethylhexyl methacrylate, methyl acrylate,
Examples thereof include ethyl acrylate and butyl acrylate. Methyl methacrylate is particularly preferable.

The composition ratio of the aromatic vinyl-based monomer (i), the vinyl cyanide-based monomer (ii), and the alkyl (meth) acrylate-based monomer (iii) is (i) 10 to 50% by weight. %, (Ii) 0 to 10% by weight, and (iii) 50 to 90% by weight. If the aromatic vinyl-based monomer (i) is less than 10% by weight, the fluidity is poor, and if it exceeds 50% by weight, discoloration during outdoor use is large, which is not preferable. The larger the proportion of the vinyl cyanide-based monomer (ii), the better the impact resistance, but the discoloration during outdoor use is large, and it is not preferable if it exceeds 10% by weight.
The alkyl (meth) acrylate-based monomer (iii) is 50
If it is less than 10% by weight, discoloration during outdoor use is large,
If it exceeds, fluidity is poor and it is not preferable.

The intrinsic viscosity of the copolymer (B) (30
℃, dimethylformamide) is not particularly limited,
It is preferably 0.2 to 1.2.

There are no particular restrictions on the method of polymerizing the copolymer (B) in the present invention, and known emulsion polymerization methods, bulk polymerization methods, solution polymerization methods, suspension polymerization methods, or any combination of these polymerization methods may be used. Can be adopted.

The thermoplastic resin composition of the present invention comprises 15 to 80 parts by weight of the graft copolymer (A) and the copolymer (B).
20 to 85 parts by weight [total 100 parts by weight of components (A) and (B)]. If the amount of the graft copolymer (A) is less than 15 parts by weight, the strength of the molded article will be reduced, and if it exceeds 80 parts by weight, discoloration during outdoor use will be large, which is not preferable.

The ratio of the rubber component derived from the graft copolymer (A) component in the resin composition is 5 to 5.
It is preferably 40% by weight. If the proportion is less than 5% by weight, the strength of the molded article will decrease, and if it exceeds 40% by weight, the fluidity will be poor, such being undesirable.

The thermoplastic resin composition of the present invention can be obtained in the form of pellets by melt-kneading using a known apparatus such as Banbury mixer, roll mill, twin-screw extruder. The obtained resin composition may also include a conventionally known antioxidant, an ultraviolet absorber, a light stabilizer, a plasticizer, if necessary.
Lubricants, flame retardants, pigments, dyes, fillers, fiber reinforcing agents and the like can be appropriately added. It can also be used as a polymer alloy with engineering plastics such as polycarbonate, polyamide, polybutylene terephthalate, polyethylene terephthalate and polyphenylene oxide.

The resin composition thus obtained can be obtained as various molded parts by molding by known molding methods such as injection molding, extrusion molding, compression molding, injection compression molding and blow molding.

[Examples] The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.

[Reference Example 1] Composite rubber latex (H-
1) Production of pure water 300 parts, sodium dodecylbenzenesulfonate 1 part, octamethylcyclotetrasiloxane 99
Part, and a mixed solution of tetraethoxysilane 1 part were mixed with an ultrasonic emulsifier for 1 hour to prepare an organosiloxane emulsion. Next, 100 parts of pure water and 1 part of dodecylbenzene sulfonic acid were charged into a nitrogen-replaced glass reactor, the temperature was raised to 90 ° C., and the previously prepared organosiloxane emulsion was added dropwise over 2 hours. After the dropping was completed, the polymerization was continued at 90 ° C. for 4 hours as it was, and after that, the temperature was kept at 5 ° C. for 72 hours and then adjusted to pH = 7.0 with an aqueous sodium hydrogen carbonate solution. Thus, a polyorganosiloxane rubber latex (S-1) having a weight average particle diameter of 0.17 μm was obtained. Next, 12 parts of polyorganosiloxane rubber latex (S-1) (as solid content), 130 parts of pure water and 0.3 part of potassium persulfate were charged into a nitrogen-substituted glass reactor and the temperature was raised to 65 ° C. Then, 20 parts of an emulsifier aqueous solution containing a mixed monomer solution consisting of 87 parts of butyl acrylate and 1 part of allyl methacrylate and 1.1 parts of potassium oleic acid salt (OS soap manufactured by Kao) was continuously added for 4 hours. Then, the polymerization was continued for 3 hours. In this way, a composite rubber latex (H-
1) was obtained.

[Reference Example 2] Graft copolymer (A-1)
In a glass reactor purged with nitrogen, 50 parts of composite rubber latex (H-1) (as solid content), 80 parts of pure water, 0.2 part of dextrin, 0.1 part of anhydrous sodium pyrophosphate.
Parts and 0.005 parts ferrous sulfate,
The temperature was raised to ° C. Then, 20 parts of an emulsifier aqueous solution containing a mixed solution of 7 parts of acrylonitrile, 43 parts of styrene, 0.3 part of cumene hydroperoxide and 1.1 parts of potassium oleic acid salt (OS soap manufactured by Kao) was continuously added over 4 hours. . Then, the polymerization was continued for 3 hours to complete the polymerization. Then, salting out, dehydration and drying were performed to obtain a graft polymer (A-1).

[Reference Example 3] Graft copolymer (A-2)
In a glass reactor purged with nitrogen, 50 parts of composite rubber latex (H-1) (as solid content), 80 parts of pure water, 0.2 part of dextrin, 0.1 part of anhydrous sodium pyrophosphate.
Parts and 0.005 parts ferrous sulfate,
The temperature was raised to ° C. Then, 20 parts of an aqueous emulsifier solution containing a mixed solution of 13 parts of acrylonitrile, 37 parts of styrene, 0.3 part of cumene hydroperoxide, and 1.1 parts of potassium oleate (OS soap manufactured by Kao) was continuously added over 4 hours. . Then, the polymerization was continued for 3 hours to complete the polymerization. Then, salting out, dehydration and drying were performed to obtain a graft polymer (A-2).

[Reference Example 4] Graft copolymer (A-3)
In a glass reactor purged with nitrogen, 50 parts of composite rubber latex (H-1) (as solid content), 80 parts of pure water, 0.2 part of dextrin, 0.1 part of anhydrous sodium pyrophosphate.
Parts and 0.005 parts ferrous sulfate,
The temperature was raised to ° C. Then, 35 parts of methyl methacrylate, 15 parts of styrene, 0.3 parts of cumene hydroperoxide.
Part mixture and potassium oleate (Kao OS
Soap) 20 parts of an emulsifier aqueous solution containing 1.1 parts was continuously added over 4 hours. Then, the polymerization was continued for 3 hours to complete the polymerization. Then, salting out, dehydration and drying were performed to obtain a graft polymer (A-3).

Reference Example 5 Production of Copolymer (B-1) A nitrogen-substituted glass reactor was charged with 130 parts of pure water and 0.3 part of potassium persulfate, and then heated to 65 ° C. Thereafter, 30 parts of an emulsifier aqueous solution containing 70 parts of methyl methacrylate, 30 parts of styrene and 0.30 part of t-dodecyl mercaptan and 1.0 part of an alkenylsuccinic acid potassium salt (Latemur ASK manufactured by Kao Corporation) were respectively added. Polymerization was completed by continuously adding over a period of time and then continuing the polymerization for 2 hours. Then, salting out, dehydration and drying were performed to obtain a copolymer (B-1).

Reference Example 6 Production of Copolymer (B-2) A nitrogen-substituted glass reactor was charged with 130 parts of pure water and 0.30 part of potassium persulfate, and then heated to 65 ° C. Thereafter, a mixed monomer solution consisting of 60 parts of methyl methacrylate, 2 parts of acrylonitrile, 38 parts of styrene and 0.30 part of t-dodecyl mercaptan and an alkenylsuccinic acid potassium salt (Latemur A manufactured by Kao Corporation).
30 parts of an aqueous emulsifier solution containing 1.0 part of SK) was continuously added over 4 hours, and then the polymerization was continued for 2 hours to complete the polymerization. Then, salting out, dehydration and drying were performed to obtain a copolymer (B-2).

Reference Example 7 Production of Copolymer (B-3) A glass reactor purged with nitrogen was charged with 130 parts of pure water and 0.3 part of potassium persulfate, and then heated to 65 ° C. Then 25 parts of acrylonitrile, styrene
A mixed monomer solution consisting of 75 parts and 0.30 part of t-dodecyl mercaptan and 30 parts of an emulsifier aqueous solution containing 1.0 part of alkenylsuccinic acid potassium salt (Latemul ASK manufactured by Kao Corporation) were continuously added for 4 hours, respectively, and thereafter. The polymerization was continued for 2 hours, and the polymerization was completed. Then, salting out, dehydration and drying were performed to obtain a copolymer (B-3).

Examples I to II, Comparative Examples I to VII 40 parts of the graft copolymer (A) shown in Table 1 and the copolymer (B-
1) To 60 parts, 0.1 part by weight of an ultraviolet absorber (Ciba Specialty Chemicals Co., Tinuvin-P) and 0.1 part by weight of a light stabilizer (Ciba Specialty Chemicals Co., Tinubin 770) Mix parts, 40
The mixture was melt-kneaded and pelletized at 240 ° C. using a mm twin screw extruder. A test piece was molded from the obtained pellet with an injection molding machine. The methods of measuring various physical properties in each Example and Comparative Example were based on the following methods.

[0036]Impact resistance Notched Izod impact according to ASTM D-256
The strike strength was measured. 23 ° C, 1/4 inch. Unit: MP
a.Liquidity Melt flow rate according to ASTM D1238
It was measured. 220 ° C, load 10 kg.Gloss Compliant with ASTM D 523-62 (60 ° specular gloss)
And measured.Colorimetry It was measured according to JIS Z8729.Weatherability 50mm x 50mm x 3mm square plate with sunshine
The meter (Suga Test Instruments Co., Ltd.) at 63 ° C with rain
And the degree of gloss retention and discoloration after exposure for 800 hours
(ΔE) was evaluated. Here, the gloss retention rate is
Calculated according to (1). Gloss retention = (Gloss after exposure / Gloss before exposure) x 100 (1)

[0037]

[Table 1]

[0038]

As described above, the resin composition of the present invention is
It has an excellent balance of impact resistance and workability, has little discoloration during outdoor use, and has good gloss retention at the same time, and can be suitably used especially in applications requiring weather resistance. The above utility value is extremely large.

Claims (3)

[Claims] 1. A composite rubber-like polymer comprising a polyorganosiloxane component and a polyalkyl (meth) acrylate component, and an aromatic vinyl monomer (46 to 80% by weight),
15 to 80 parts by weight of a composite rubber-based graft copolymer (A) obtained by polymerizing 5 to 24% by weight of a vinyl cyanide-based monomer and 0 to 30% by weight of an alkyl (meth) acrylate-based monomer, and an aromatic compound. Copolymer (B) 20 obtained by polymerizing 10 to 50% by weight of vinyl-based monomer, 0 to 10% by weight of vinyl cyanide-based monomer, and 50 to 90% by weight of alkyl (meth) acrylate-based monomer. To 85 parts by weight [total 100 parts by weight of components (A) and (B)]. 2. The thermoplastic resin composition according to claim 1, wherein the proportion of the polyorganosiloxane component in the composite rubber-like polymer is 3 to 20% by weight. 3. The thermoplastic resin composition according to claim 1, wherein the composite rubber-like polymer has a weight average particle diameter of 0.05 to 0.3 μm.