JPH11286587A - Thermoplastic resin composition and coated molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition comprising a polyamide and an ABS alloy, having excellent impact resistance and moldability and having excellent dimensional stability after coated and cured, and to provide a coated molded product. SOLUTION: This thermoplastic resin composition comprises (A) 10-50 pts.wt. of a polyamide resin, (B) 10-80 pts.wt. of a graft polymer prepared by graft- polymerizing 90-20 wt.% of a monomer mixture comprising 50-90 wt.% of an aromatic vinyl and 10-50 wt.% of a vinyl cyanide in the presence of 10-80 wt.% of a dienic rubber, (C) 5-40 pts.wt. of an unsaturated carboxylic acid-modified copolymer comprising 0.5-20 wt.% of an unsaturated carboxylic acid, 50-89.5 wt.% of an aromatic vinyl and 10-49.5 wt.% of a vinyl cyanide, and (D) 5-40 pts.wt. of a maleimide-based copolymer comprising 20-80 wt.% of an aromatic vinyl, 5-60 wt.% of maleimide, and 0-40 wt.% of one or more other copolymerizable monomers (the total amount of the components A, B, C and D is 100 pts.wt.). The coated molded product is prepared by coating a resin molded product comprising the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic resin composition. More specifically, the present invention relates to a thermoplastic resin composition having excellent impact resistance, excellent moldability, and excellent dimensional stability after coating baking, and a coated molded article obtained by applying a coating to a resin molded article made of the resin composition. is there.

[0002]

2. Description of the Related Art Polyamide resin has chemical resistance, heat resistance,
It is a resin excellent in abrasion resistance and the like, and is widely used as an automobile part and an electric / electronic part, but has a drawback of poor impact resistance. ABS resin (acrylonitrile-butadiene-styrene copolymer resin) is a resin having excellent impact resistance and moldability, and is widely used as office equipment parts, electric parts, automobile parts, etc. However, it has a drawback of poor abrasion resistance. Therefore, in order to compensate for these disadvantages, polyamide resin and ABS
A blend of resins, that is, a polyamide / ABS alloy has been proposed (Japanese Patent Publication No. 38-23476). However, since the polyamide resin and the ABS resin have poor compatibility, as a method for improving the compatibility, a method of blending a modified copolymer obtained by copolymerizing an unsaturated carboxylic acid with styrene and acrylonitrile has been proposed. (JP-A-63-179957 and JP-A-64-158). These methods have shown improvements in compatibility and some improvements in impact resistance and the like have been recognized. On the other hand, resin molded articles made of these materials, particularly exterior parts for vehicles, and the like, are sometimes coated for the purpose of improving design. In this case, the baking temperature and the time vary depending on the type of paint used for painting. For this reason, when the coating conditions of the paint to be used are not adapted, the dimensional stability after coating is poor, and the commercial value as a coated part is significantly reduced. Also, in consideration of the paintability of polyamide / ABS alloy, it is necessary to increase the blending ratio of polyamide, but in that case, "sink" tends to occur in the molded product. Accordingly, in a polyamide / ABS alloy, a resin composition which is excellent in impact resistance, moldability and not only paintability but also dimensional stability after paint baking in a region where the blending ratio of polyamide is restricted is desired. It is rare.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyamide / ABS alloy which is excellent in impact resistance, moldability and dimensional stability after baking. It is.

[0004]

SUMMARY OF THE INVENTION The present invention provides an impact-resistant, molding composition comprising a polyamide resin and an ABS resin mixed with an unsaturated carboxylic acid-modified copolymer and a maleimide copolymer having a specific composition. The present invention provides a resin composition having excellent paintability and coatability. In the present invention, particularly as a diene rubber component of the graft polymer constituting the ABS resin,
By using a coagulated and enlarged rubber obtained by coagulating a small particle rubber having a specific particle diameter, a resin composition having a better balance of impact resistance and moldability can be obtained.

That is, the present invention relates to a polyamide resin (A)
In the presence of 10 to 50 parts by weight of a diene rubber, 10 to 80% by weight of a diene rubber, 50 to 90% by weight of an aromatic vinyl monomer and 10 to 50% by weight of a vinyl cyanide monomer, a monomer mixture 90 to 90% by weight. 10 to 80 parts by weight of a graft polymer (B) obtained by graft polymerization of 20% by weight, 0.5 to 20% by weight of an unsaturated carboxylic acid monomer, and 50 to 8 of an aromatic vinyl monomer
9.5% by weight and vinyl cyanide monomer 10-4
5 to 40 parts by weight of an unsaturated carboxylic acid-modified copolymer (C) obtained by polymerizing 9.5% by weight, 20 to 80% by weight of an aromatic vinyl monomer, and 5 to 60% by weight of a maleimide monomer
And 5 to 40 parts by weight of a maleimide copolymer (D) obtained by polymerizing 0 to 40% by weight of another copolymerizable monomer [provided that (A), (B), (C) and (D) 100
Parts by weight].

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyamide resin (A) used in the present invention includes nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 116, nylon 11, nylon 12, nylon 6I,
Nylon 6/66, Nylon 6T / 6I, Nylon 6 /
6T, nylon 66 / 6T, polytrimethylhexamethylene terephthalamide, polybis (4-aminocyclohexyl) methandodecamide, polybis (3-methyl-4
-Aminocyclohexyl) methandodecamide, polymethaxylylene adipamide, nylon 11T, polyundecamethylene hexahydroterephthalamide and the like. Here, "I" indicates an isophthalic acid component, and "T" indicates a terephthalic acid component.

Of these, nylon 6, nylon 46, nylon 66, nylon 6T / 6I, nylon 6
/ 6T and nylon 66 / 6T are preferred.

[0008] The graft polymer (B) used in the present invention is defined as 50 to 90% by weight of an aromatic vinyl monomer and 10 to 80% by weight of a vinyl cyanide monomer in the presence of 10 to 80% by weight of a diene rubber. Monomer mixture 9 consisting of 50% by weight
It is a graft polymer obtained by graft polymerization of 0 to 20% by weight.

The diene rubber constituting the graft polymer (B) is a polymer obtained by polymerizing a monomer containing 50% by weight or more of a diene monomer represented by, for example, 1,3-butadiene. Other monomers copolymerizable with the diene monomer include aromatic vinyl monomers such as styrene and α-methylstyrene, and vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. And unsaturated carboxylic acid alkyl ester-based monomers such as methyl acrylate, ethyl acrylate and methyl methacrylate. Specifically, it is a polybutadiene, a butadiene-styrene copolymer, a butadiene-acrylonitrile copolymer, or a butadiene-methyl methacrylate copolymer. The gel content (solvent: toluene) of the diene rubber is not particularly limited, but preferably 60 to 95% by weight.

Examples of the aromatic vinyl monomer constituting the graft polymer (B) include styrene, α-methylstyrene, paramethylstyrene, chlorostyrene, bromostyrene, and the like. One or more kinds may be used. be able to. Particularly, styrene and α-methylstyrene are preferred.
Acrylonitrile, as a vinyl cyanide monomer,
Methacrylonitrile and the like can be mentioned, and one kind or two or more kinds can be used. Acrylonitrile is particularly preferred. Further, in the present invention, a part of the aromatic vinyl-based monomer may be another copolymerizable vinyl-based monomer such as maleimide, methylmaleimide, ethylmaleimide, N-
Maleimide monomers such as phenylmaleimide and O-chloro-N-phenylmaleimide; unsaturated carboxylic acid ester monomers such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and 2-ethylhexyl acrylate; It may be replaced.

In the present invention, small particle rubber having a specific particle diameter is preferably used as the diene rubber constituting the graft polymer (B) in view of the balance between impact resistance and moldability, and further from the viewpoint of coatability. It is preferable to use a coagulated and enlarged rubber obtained by coagulation. Specifically, it is possible to use a diene rubber latex obtained by coagulating and enlarging a small particle diene rubber latex having a weight average particle diameter of 0.05 to 0.20 μ to a weight average particle diameter of 0.20 to 0.8 μ. preferable.
As a method of coagulating and enlarging the small particle diene rubber latex, a conventionally known method, for example, a method of adding an acidic substance (Japanese Patent Publication No. 42-3112, Japanese Patent Publication No. 55-192)
46, Japanese Patent Publication No. Hei 2-9601, JP-A-63-11700
5, JP-A-63-132903, JP-A-7-15750
1, JP-A-8-259777), and a method of adding an acid group-containing latex (JP-A-56-166201, JP-A-59-166201)
-93701, JP-A-1-126301, JP-A-8-5
9704) can be adopted, and there is no particular limitation.

The method for producing the above graft polymer is not particularly limited, and it can be polymerized by an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method or a combination thereof. When a rubber latex is used, a usual emulsion polymerization method can be employed, and known emulsifiers, initiators, and various auxiliaries can be used without any limitation.

The unsaturated carboxylic acid-modified copolymer (C) used in the present invention is defined as 0.5 to 20% by weight of an unsaturated carboxylic acid monomer and 50 to 8% of an aromatic vinyl monomer.
9.5% by weight and vinyl cyanide monomer 10-4
It is a copolymer obtained by polymerizing 9.5% by weight.

The unsaturated carboxylic acid monomer constituting the copolymer (C) includes acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like, and one or more of them may be used. it can. Particularly, methacrylic acid is preferred. As the aromatic vinyl monomer and the vinyl cyanide monomer, the same ones as exemplified in the section of the graft polymer (B) can be used. Further, a part of the aromatic vinyl monomer may be another copolymerizable vinyl monomer, for example, methyl acrylate, ethyl acrylate,
Methyl methacrylate, ethyl methacrylate, 2
-May be substituted with an unsaturated carboxylic acid ester monomer such as ethylhexyl acrylate.

In the production of the copolymer (C), known emulsion polymerization, bulk polymerization, suspension polymerization and solution polymerization can be employed. The method of adding the unsaturated carboxylic acid monomer is not particularly limited, and a method of mixing with another monomer and adding it to the polymerization system, a method of adding it as an aqueous solution, and the like can be adopted.

The maleimide-based copolymer (D) used in the present invention includes 20 to 80% by weight of an aromatic vinyl monomer, 5 to 60% by weight of a maleimide-based monomer and another copolymerizable monomer. It is a copolymer obtained by polymerizing 0 to 40% by weight of a monomer. As the aromatic vinyl monomer constituting the copolymer (D), the same ones as those exemplified in the section of the graft polymer (B) can be used. Examples of the maleimide-based monomer include maleimide, methylmaleimide, ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, O-chloro-N-phenylmaleimide, and the like, and one or more kinds thereof can be used. Particularly, N-phenylmaleimide is preferred. Further, as other copolymerizable monomers, for example, acrylonitrile, vinyl cyanide monomers such as methacrylonitrile,
Methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, unsaturated carboxylic acid ester-based monomers such as 2-ethylhexyl acrylate, unsaturated dicarboxylic anhydrides such as maleic anhydride, and the like. Two or more types can be used.

In the preparation of the copolymer (D), 20 to 80% by weight of an aromatic vinyl monomer, 5 to 60% by weight of a maleimide monomer and 0 to 80% of another copolymerizable monomer are used.
A method (1) for producing a copolymer (D) having a desired composition by polymerizing a monomer component consisting of 40% by weight, a method in which an aromatic vinyl monomer and maleic anhydride or a monomer copolymerizable therewith are used. After polymerizing the monomer component consisting of a monomer, the obtained copolymer is reacted with ammonia or a primary amine such as methylamine, ethylamine or aniline to imidize a maleic anhydride residue, There is a method (2) for producing a copolymer (D) having a desired composition, and any of them may be employed. In the case of the above (1), a copolymer can be obtained by a known emulsion polymerization method, bulk polymerization method, suspension polymerization method, or solution polymerization method. In the case of (2), the copolymer can be obtained by polymerizing the copolymer by a bulk polymerization method or a solution polymerization method and then performing an imidization reaction in a bulk state, a solution state or a suspension state. it can. In the case of the imidization reaction in the case of (2), it is also possible to use a melt kneading device such as a screw extruder to perform the imidization.

In the present invention, the mixing ratio of the polyamide resin (A), the graft polymer (B), the unsaturated carboxylic acid-modified copolymer (C) and the maleimide copolymer (D) is (A) 10 to 50. Parts by weight, (B) 10 to 80 parts by weight, (C) 5 to 40 parts by weight and (D) 5 to 40 parts by weight (provided that the total of (A), (B), (C) and (D) is 1
When the amount is out of this range, the desired composition of the present invention cannot be obtained. Also,
From the viewpoint of the balance of physical properties of the composition, the content of the diene rubber in the entire composition is preferably in the range of 5 to 40% by weight.

The order of mixing the polyamide resin (A), the graft polymer (B), the unsaturated carboxylic acid-modified copolymer (C) and the maleimide-based copolymer (D) and the state thereof are not particularly limited. Examples of the method include the simultaneous simultaneous mixing of the components (A), (B), (C), and (D), and the mixing of the components remaining after premixing of the specific two components, depending on the form of the pellets. For such melt mixing, a Banbury mixer, a roll, an extruder, or the like can be used. In addition, upon mixing, if necessary, other styrene-based copolymers such as styrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile copolymer, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, and other phenylene ether. Thermoplastic resin, furthermore antioxidant, ultraviolet absorber, light stabilizer, antistatic agent, lubricant, dye, pigment, plasticizer, flame retardant, release agent, glass fiber, metal fiber, carbon fiber, metal flake, etc. Known additives, reinforcing materials, fillers and the like can be added.

Hereinafter, the present invention will be described in detail.
It should be noted that the present invention is not limited at all by this. All parts and percentages are shown on a weight basis.

Reference Example 1 100 parts of 1,3-butadiene, 0.3 part of t-dodecylmercaptan, 0.25 part of potassium persulfate, 2.5 parts of sodium rosinate were placed in a pressure vessel.
Parts, 0.1 part of sodium hydroxide and 170 parts of pure water were charged, and after the temperature was raised to 80 ° C., polymerization was started. Polymerization is 10
Finished in time. The obtained diene rubber latex (b-) has a solid content of 37% and a weight average particle size of 0.1.
μ, gel content was 90%. The gel content is
After drying the latex to prepare a film, weighing about 1 g, and immersing in toluene at 23 ° C. for 48 hours,
The insolubles were filtered off and dried with a 100 mesh wire gauze, and the weight% was measured.

Reference Example 2 In a pressure vessel, 270 parts by weight of the diene rubber latex (b-) obtained in Reference Example 1 and 0.1 part of sodium dodecylbenzenesulfonate were added and mixed with stirring for 10 minutes. After that, 5% phosphoric acid aqueous solution 2
0 parts were added over 10 minutes. Then, 10 parts of a 10% aqueous potassium hydroxide solution was added, and a diene rubber latex (b) having a solid content of 34% and a weight average particle diameter of 0.3 μm was added.
-1) was obtained.

[Reference Example 3] In a pressure vessel, 50 parts (solid content) of diene rubber latex shown in Table 1, 1.5 parts of sodium dodecylbenzenesulfonate, potassium persulfate,
After charging 0.3 parts and raising the temperature to 70 ° C, styrene 35 was added.
Parts and a monomer mixture consisting of 15 parts of acrylonitrile were continuously added over 5 hours to obtain a graft polymer latex B-1. After adding 1 part of phenolic antioxidant (Sumitomo Chemical Co., Ltd .: Sumilizer BBM) and 2 parts of trisnonylphenyl phosphite as antioxidants per 100 parts by weight (solid content) of the obtained latex,
Salting out, dehydration and drying were performed using magnesium sulfate to obtain a graft polymer B-1. In the above polymerization, 60 parts of diene rubber latex (solid content) and styrene 28
In the same manner as described above except that the parts were changed to 12 parts and acrylonitrile 12 parts, to obtain a graft polymer B-2.

Reference Example 4 After 120 parts of pure water and 0.3 part of potassium persulfate were charged into a pressure vessel, the temperature was raised to 65 ° C. with stirring. Thereafter, a mixed monomer solution consisting of 63 parts of styrene, 30 parts of acrylonitrile, 7 parts of methacrylic acid and 0.3 part of t-dodecylmercaptan and 30 parts of an emulsifier aqueous solution containing 2 parts of sodium dodecylbenzenesulfonate were continuously fed for 5 hours each. After that, the polymerization system was heated to 70 ° C. and aged for 3 hours to complete the polymerization. Thereafter, salting out, dehydration and drying were performed using calcium chloride to obtain an unsaturated carboxylic acid-modified copolymer C-1. In the above polymerization, a copolymer Ci was obtained in the same manner as described above except that 70 parts of styrene and 30 parts of acrylonitrile were used as monomer components.

Reference Example-5 After 120 parts of pure water and 0.3 part of potassium persulfate were charged into a pressure vessel, the temperature was raised to 65 ° C. with stirring. Thereafter, 50 parts of styrene, 15 parts of acrylonitrile, 35 parts of N-phenylmaleimide and t
-A mixed monomer solution consisting of 0.4 parts of dodecyl mercaptan and 30 parts of an aqueous solution of an emulsifier containing 2 parts of sodium lauryl sulfate were each added continuously over 4 hours, and then the polymerization system was heated to 70 ° C and aged for 3 hours. To complete the polymerization. Thereafter, salting out, dehydration and drying were performed using calcium chloride to obtain a maleimide-based copolymer D-1.

Reference Example 6 Styrene 60 was placed in a pressure vessel.
And 100 parts of methyl ethyl ketone, and the atmosphere in the system was replaced with nitrogen gas.
A solution of 0 parts and 0.15 parts of benzoyl peroxide dissolved in 200 parts of methyl ethyl ketone was added continuously over 8 hours. After the addition was completed, the temperature was kept at 85 ° C. for 3 hours. Next, aniline 38 was added to the obtained copolymer solution.
And 140 parts of 7
Allowed to react for hours. The reaction liquid was supplied to a twin-screw extruder equipped with a vent, and devolatilized to obtain a maleimide-based copolymer D-2. According to C-13 NMR analysis, the composition of the copolymer was 46% of styrene, 52% of N-phenylmaleimide, and 2% of maleic anhydride.

Examples 1-3 and Comparative Examples 1-8 Polyamide resin (A), graft copolymers B-1 and B-2, copolymers C-1 and i and copolymer D prepared in Reference Examples -1
Were mixed at 230 ° C. using a 40 mm twin-screw extruder to form pellets, and then various test pieces were prepared with an injection molding machine to evaluate physical properties. Table 3 shows the results. As the polyamide resin (A) used in the examples and comparative examples, nylon 6 (unitika nylon 6A1030BRL, manufactured by Unitika) was used.

O Impact resistance: according to ASTM D-256. 1/8 inch, 23 ° C. o Moldability: Based on ASTM D-1238. 265
° C, 5 kg. o Dimensional stability after baking: 200m with injection molding machine
After molding a box-shaped molded product having a size of mx 200 mm x 40 mm (depth) x 2.5 mm, and applying a one-component organic solvent-based acrylic paint to the obtained molded product using an air spray gun, It was baked and dried at 120 ° C. for 60 minutes. The dimensional stability (degree of deformation) of the obtained coated molded product was visually judged. Good: Good, Bad: No o Mold sink: 150 mm x 150 by injection molding machine
mm x 3mm thick and 10m deep (height) in the center
A molded product having a rib of mx 1.5 mm thickness was molded, and 23
After standing for 24 hours in a constant temperature room at 50 ° C. × 50% RH, the degree of sink on the back of the rib was visually determined. No sink marks: ○,
Sinking stands out: ×

[0029]

[Table 1]

[0030]

The resin composition of the present invention has excellent impact resistance, moldability and dimensional stability after baking as described above, and is particularly useful in applications requiring painting.

Claims (3)

[Claims] 1. A polyamide resin (A) of 10 to 50 parts by weight, an aromatic vinyl monomer of 50 to 90% by weight and a vinyl cyanide monomer of 10 to 80% by weight in the presence of a diene rubber of 10 to 80% by weight. Monomer mixture 90-2 consisting of 50% by weight
Graft polymer (B) obtained by graft polymerization of 0% by weight
10 to 80 parts by weight, unsaturated carboxylic acid monomer 0.5 to 2
0% by weight, aromatic vinyl monomer 50 to 89.5% by weight
5 to 40 parts by weight of an unsaturated carboxylic acid-modified copolymer (C) comprising 10 to 49.5% by weight of a vinyl cyanide monomer, 20 to 80% by weight of an aromatic vinyl monomer, 5 to 40 parts by weight of a maleimide-based copolymer (D) comprising 5 to 60% by weight of a monomer and 0 to 40% by weight of another copolymerizable monomer [(A), (B), (C) And the total of (D) is 100 parts by weight]. 2. A diene obtained by coagulating and enlarging a small particle diene rubber latex having a weight average particle diameter of 0.05 to 0.20 μm to a weight average particle diameter of 0.20 to 0.8 μm. Monomer mixture of 50 to 90% by weight of an aromatic vinyl monomer and 10 to 50% by weight of a vinyl cyanide monomer in the presence of 10 to 80% by weight of a rubber based latex (solid content) The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is a graft polymer obtained by graft-polymerizing a percentage by weight. 3. A coated molded article obtained by applying a coating to a resin molded article comprising the thermoplastic resin composition according to claim 1.