JPH1160882A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin compsn. excellent in the balance among heat resistance, impact strength and moldability by mixing a methacrylic polymer obtd. by the copolymn. with an N-substd. maleimide compd. with a rubber-reinforced styrene resin. SOLUTION: This compsn. is obtd. by mixing and kneading 1-70 pts.wt. methacrylic polymer (A) comprising 70-99 wt.% units derived from methyl methacrylate, 1-15 wt.% units derived from an N-substd. maleimide compd. and 0-15 wt. % units derived from another monomer copolymerizable with the foregoing monomers with 99-30 pts.wt. rubber-reinforced styrene resin (B) obtd. by the graft polymn. of styrene and acrylonitrile or the like in the presence of a rubber component. A copolymer formed from methyl methacrylate, N- cyclohexylmaleimide, and styrene is pref. as ingredient A. A graft polymer formed from 15-80 wt.% styrene, 2-50 wt.% acrylonitrile, and 10-70 wt.% rubber component is pref. as ingredient B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and more particularly, to a thermoplastic resin composition having a good balance among heat resistance, impact resistance, and moldability.

[0002]

2. Description of the Related Art In the fields of electric appliances, automobiles, office products, etc., ABS obtained by graft-polymerizing acrylonitrile and styrene to a rubber component mainly composed of a diene compound such as butadiene and ethylene-propylene and / or an olefin compound. Processability of resin, AES resin, etc.
Although rubber-reinforced styrene-based resins having excellent mechanical strength and the like have been used, in recent years, particularly in applications such as automobile interior parts, demands for improvement in heat resistance have been increasing.

As a method for improving the heat resistance of a rubber-reinforced styrene resin, for example, a method of replacing part or all of styrene with α-methylstyrene (Japanese Patent Publication No.
No. 37415) has been proposed. However,
Although heat resistance can be improved by this method, the balance of various properties such as heat resistance, impact resistance and moldability is not sufficient, and the market requirements are not sufficiently satisfied. is there. Further, since the rubber-reinforced styrene-based resin is a rubber-like polymer, it has a problem that it has a low surface hardness and is easily damaged. For example, when used as an automobile part, it is easily damaged by a car wash brush or the like. Since the occurrence of such scratches deteriorates the glossy appearance of the rubber-reinforced styrene resin and impairs the commercial value,
Conventionally, it has been necessary to further coat the surface of the molded article or to apply a surface protective coat to suppress the occurrence of scratches. However, such post-processing such as painting and protective coating not only complicates the manufacturing process, but also
This is a factor that raises costs.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems and to provide a thermoplastic resin composition having a good balance of heat resistance, impact resistance and moldability. .

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a methacrylic polymer (A) having a specific composition and a rubber-reinforced styrene resin (B) have a specific composition. It has been found that the above-mentioned problems can be achieved by blending at a ratio, and the present invention has been completed.

[0006] That is, according to the present invention,
(A) 70-99% by weight of methyl methacrylate unit, N-
1 to 70 parts by weight of a methacrylic polymer composed of 1 to 15% by weight of a substituted maleimide compound unit and 0 to 15% by weight of another monomer unit copolymerizable therewith, and (B) a rubber-reinforced styrene resin 99 to This can be achieved by a thermoplastic resin composition comprising 30 parts by weight.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The methacrylic polymer (A) used in the present invention
Is a component mainly for improving the heat resistance of the resin composition, and contains 70 to 99% by weight, preferably 70 to 98% by weight, more preferably 80 to 94% by weight of methyl methacrylate units, and N-substituted maleimide compound unit 1. To 15% by weight, and 0 to 15% by weight of other monomer units copolymerizable therewith. When the content of the methyl methacrylate unit is less than 70% by weight, transparency,
If the content exceeds 99% by weight, the desired heat resistance cannot be obtained, which is not preferred.

The monomer constituting the N-substituted maleimide unit is not particularly limited, but may be N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, Phenylmaleimide, N-tolylmaleimide, N-xylylmaleimide, N-naphthylmaleimide, Nt-butylmaleimide, N-orthochlorophenylmaleimide, N-orthomethoxyphenylmaleimide, N-orthobromophenylmaleimide and the like. . Of these, N-cyclohexylmaleimide is particularly preferably used. One or two or more of these N-substituted maleimides can be used. N
It is necessary that the content of the substituted maleimide compound unit is in the range of 1 to 15% by weight, preferably 3 to 12% by weight. When the content of the N-substituted maleimide unit is less than 1% by weight, desired heat resistance cannot be obtained, which is not preferable. On the other hand, if the content exceeds 15% by weight, the moldability is not sufficient, which is not preferable.

The monomer constituting another monomer unit copolymerizable with methyl methacrylate and N-substituted maleimide is not particularly limited, and for example, aromatic monomers such as styrene, vinyltoluene and α-methylstyrene. Vinyl compounds; acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, phenyl methacrylate, tribromophenyl methacrylate, Methacrylic esters other than methyl methacrylate such as dicyclopentanyl methacrylate; acrylic acid, methacrylic acid,
Acrylonitrile, methacrylonitrile, vinyl acetate and the like can be mentioned. Of these, styrene is particularly preferably used. The content of other copolymerizable monomer units is 0 to
It is in the range of 15% by weight, preferably 1-15% by weight, more preferably 3-12% by weight. When the content of other copolymerizable monomer units exceeds 15% by weight, heat resistance,
It is not preferable because mechanical strength and transparency may be lowered.

The method for producing the methacrylic polymer (A) is not particularly limited, and known methods such as bulk polymerization, suspension polymerization, solution polymerization and emulsion polymerization can be employed. The polymerization initiator used for these polymerizations is usually benzyl peroxide, lauroyl peroxide, tert-butylperoxy-2-ethylhexanoate, di-te
peroxide initiators such as rt-butylperoxyhexahydroterephthalate; 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, azobiscyclohexanone-1- An azo initiator such as carbonitrile; a redox initiator is used. Examples of the chain transfer agent optionally used include mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan; thioglycolic acid; and α-methylstyrene dimer. Methacrylic polymer (A) obtained by the above production method
It is preferable that the content of the remaining N-substituted maleimide-based monomer is as low as possible, and it is usually 1000 pp by employing post-polymerization and using an initiator having a different activation temperature in combination.
m or less. Further, the methacrylic polymer (A) has an intrinsic viscosity of 0.3 to 0.7 dl / g, preferably 0.4 to 0.7 dl / g.
It is desirable to be within the range of 0.6 dl / g from the viewpoint of achieving a good balance between mechanical strength, moldability and the like.

The rubber-reinforced styrenic resin (B) used in the present invention is a component that exhibits impact resistance. For example, a component such as styrene and acrylonitrile is graft-polymerized in the presence of a rubber component such as polybutadiene or EPDM. It can be obtained by Representative examples of these are ABS resin (acrylonitrile-butadiene rubber-styrene copolymer), AES resin (acrylonitrile-ethylene-propylene rubber-styrene copolymer),
Examples include, but are not limited to, AAS resins (acrylonitrile-acrylic rubber-styrene copolymer), ACS resins (acrylonitrile-chlorinated polyethylene-styrene copolymer). As a method for producing the rubber-reinforced styrene-based resin, generally known methods such as emulsion polymerization, bulk polymerization, solution polymerization, emulsion-suspension polymerization, and emulsion-bulk polymerization can be employed, but emulsion polymerization is particularly preferably used.
The composition ratio of each component in the rubber-reinforced styrene resin obtained by these methods is not particularly limited,
Also, if other copolymerizable monomers are used as desired, an inorganic compound or the like may be blended,
Usually 15 aromatic vinyl compounds mainly composed of styrene
-80% by weight, preferably 30-70% by weight, unsaturated nitrile compound is 2-50% by weight, preferably 10-40% by weight, rubber component is 10-70% by weight, preferably 20-70% by weight.
Those obtained by blending the respective components so as to be in the range of 60% by weight are preferably used. The graft ratio in the rubber-reinforced styrene-based resin is not particularly limited, but is generally preferably in the range of 20% to 80%.

The thermoplastic resin composition of the present invention comprises 1 to 70 parts by weight, preferably 5 to 70 parts by weight, more preferably 40 to 60 parts by weight of the methacrylic polymer (A) and a rubber-reinforced styrene resin (B). ) 99-30 parts by weight, preferably 9
It is composed of 5 to 30 parts by weight, more preferably 60 to 40 parts by weight, and can usually be obtained by mixing and kneading these resins. Methacrylic polymer (A)
If the amount is less than 1 part by weight, the heat resistance is lowered, which is not preferable. On the other hand, if the amount of the rubber-reinforced styrene resin (B) is less than 30 parts by weight, the impact resistance is inferior.

In the present invention, methacrylic polymer (A) and rubber-reinforced styrene resin (B), which are essential components, are used.
In addition, other thermoplastic resin (C) can be blended as an optional component, and for example, heat resistance, moldability and the like can be further improved. The thermoplastic resin (C) used for these purposes is not particularly limited. For example, methacrylic resins (excluding those containing an N-substituted maleimide compound unit), MS resins (methyl methacrylate) -Styrene copolymer), AS resin (acrylonitrile-styrene copolymer), αSAN resin (α-methylstyrene-acrylonitrile copolymer) and the like. Further, a resin mainly composed of structural units of glutaric anhydride may be used as the thermoplastic resin (C) for the purpose of further improving scratch resistance and surface gloss. The blending amount of these thermoplastic resins (C) depends on the methacrylic polymer (A).
And 0 to 100 parts by weight, preferably 30 parts by weight, based on 100 parts by weight of the total amount of the rubber-reinforced styrene resin (B).
It is about 50 parts by weight.

In the present invention, the organic phosphorus compound (D) can be further contained in the resin component. The organophosphorus compound (D) is contained in the resin composition and mainly serves to further improve heat resistance. The organic phosphorus compound that can be added in the present invention is not particularly limited, but tris (2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butyl-4-). Substitutes such as methylphenyl) phosphite, tris (monononylphenyl) phosphite, monononylphenylbis (dinonylphenyl) phosphite, dinonylphenylbis (monononylphenyl) phosphite, and tris (dinonylphenyl) phosphite Phosphate compound: ditridecylpentaerythritol diphosphite, diisodecylpentaerythritol diphosphite, distearylpentaerythritol diphosphite, bis (monononylphenyl) pentaerythritol diphosphite, bis (dinonylphenyl) penta Risuri diphosphite, bis (2,4-di--ter
t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentarisritol diphosphite, bis (2,6-di-tert-butyl-4-ethyl) Phenyl) pentarisritol diphosphite, bis (2,6
Pentaerythritol phosphite compounds such as -di-tert-butyl-4-methoxycarbonylphenyl) pentarisritol diphosphite and hydrogenated bisphenol A / pentaerythritol diphosphite polymer; 9,10-dihydro-9- Oxa-10-phosphaphenanthrene-10-oxide, 2-methyl-
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 6-methyl-9,1
0-dihydro-9-oxa-10-phosphephaphenanthrene-10-oxide, 2,6-dimethyl-
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 6,8-di-ter
t-butyl-9,10-dihydro-9-oxa-10-
Phosphaphenanthrene-10-oxide, 6-methoxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-methyl-9,10-dihydro-9-oxa- 10-phosphenanthrene-10-oxide, 10-ethoxy-
A phosphaphenanthrene-based compound such as 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide is preferably used as the organic phosphorus compound of the present invention.

Preferred examples of these organic phosphorus compounds include dinonylphenylbis (monononylphenyl) phosphite, ditridecylpentaerythritol diphosphite, diisodecylpentaerythritol diphosphite, and 9,10-dihydro-9. -Oxa-
10-phosphaphenanthrene-10-oxide and the like. These organic phosphorus compounds can be used alone or in combination of two or more. The content thereof is based on 100 parts by weight of the total amount of the methacrylic polymer (A) and the rubber-reinforced styrene resin (B). , Usually 0.005 to 1 part by weight, preferably 0.01 to 0.5 part by weight.

In the thermoplastic resin composition of the present invention,
An ultraviolet absorber, an antioxidant, a lubricant, a releasing agent, a dye, an antistatic agent, a flame retardant, a coloring inhibitor, and the like can be added as needed within a range where the object of the present invention can be achieved.

The thermoplastic resin composition of the present invention can be used to produce molded articles by various molding and processing methods such as injection molding, extrusion molding, vacuum molding and the like. It is also possible to apply a treatment such as a plating treatment or a vacuum deposition treatment to the molded product. The thermoplastic resin composition of the present invention makes use of the mechanical properties such as mechanical strength and the glossy appearance of the methacrylic polymer (A) and the impact resistance of the rubber-reinforced styrene resin. While improving heat resistance and the like, it can be suitably used, for example, in the field of interior and exterior parts of automobiles, home electric appliances, OA equipment, and other equipment members.

[0019]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The evaluation and physical property measurement of the present invention were performed by the following methods. (1) Total light transmittance and haze Measured according to ASTM D1003.

(2) Heat deformation temperature Measured according to ASTM D648.

(3) Melt flow rate According to ASTM D1238, 220 ° C., 10 kgf
Load (Examples 1 to 12 and Comparative Example 1) and 230
C. and 5 kgf load (Example 13 and Comparative Example 2).

(4) Izod impact strength Measured with a notch according to ASTM D256.

(5) Rockwell hardness Measured on an R scale according to ASTM D785.

(6) Dropping weight impact strength Using an impact tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), a striker (hammer); 12.7 mm; a test piece holder (span diameter); 43.0 mm; ; 2.4 m / s
ec, measurement temperature: measured at 23 ° C.

(7) Intrinsic Viscosity The intrinsic viscosity in chloroform at 20 ° C. was measured using an Ubelode viscometer (manufactured by Iwamoto Seisakusho; automatic dilution capillary viscometer).

The following resin was used. (1) Methacrylic polymer (A) N-cyclohexylmaleimide (CHMI) 6% by weight,
Methyl methacrylate (MMA) 91% by weight, styrene (ST) 3% by weight, lauroyl peroxide 0.3p
hr, n-octyl mercaptan 0.33 phr of a monomer mixture solution (24 kg), sodium methacrylate and styrene-P-sodium sulfonate copolymer 0.3
48 kg of aqueous solution consisting of 10% by weight
The reactor was charged into a 0-liter pressure-resistant polymerization tank, and while stirring under a nitrogen atmosphere, warm water was passed through the jacket to start suspension polymerization at 70 ° C. Four hours after the start of the polymerization, the polymerization system was heated to 120 ° C. through steam through the jacket, and further maintained for 2 hours to complete the polymerization. The obtained polymer was washed with water and dried to obtain uniform copolymer beads (A-1). Also, polymers (A-2) to (A-4) were obtained in the same manner as in the method for producing polymer (A-1) except that the composition was changed to that shown in Table 1.

[0027]

[Table 1]

(2) Rubber Reinforced Styrene Resin Rubber Reinforced Styrene Resin (B-1): 45% by weight of a rubber component composed of ethylene-propylene, 40% by weight of a styrene unit, 15% by weight of an acrylonitrile unit Resin. Rubber-reinforced styrene resin (B-2): rubber component content of 35% by weight of butadiene, styrene unit content of 50
A resin having an acrylonitrile unit content of 15% by weight. Rubber-reinforced styrene resin (B-3): a resin composed of ethylene-propylene and having a rubber component content of 25% by weight, a styrene unit content of 30% by weight, and an acrylonitrile unit content of 45% by weight.

(3) Thermoplastic resin (C) Methacrylic resin (C-1): a resin having a methyl methacrylate unit content of 98% by weight and a methyl acrylate unit content of 2% by weight (intrinsic viscosity 0.55 dl / g).

(Examples 1 to 9) A mixture 10 prepared by using the above-mentioned polymer and resin as shown in Table 2 was prepared.
0 parts by weight and 0.1 parts by weight of diisodecylpentaerythritol diphosphite were blended, and a 40 mm extruder (trade name)
The mixture was melt-kneaded at a cylinder temperature of 250 ° C. using a VSK 40 mm vented extruder (manufactured by Chuo Kikai Seisakusho) to obtain pellets. Using these pellets, cylinder temperature 250 ° C,
Injection molding was performed at a mold temperature of 60 ° C. to obtain a plate-like molded product. Table 2 shows the evaluation results of the obtained molded articles.

(Example 10) A plate-like molded product was obtained in the same manner as in Example 1 except that diisodecylpentaerythritol diphosphite was not added to 100 parts by weight of the mixture having the compounding ratio of Example 1. Table 2 shows the evaluation results of the obtained molded articles.

Example 11 0.1 part by weight of dinolylphenyl (monononylphenyl) phosphite was used instead of diisodecylpentaerythritol diphosphite with respect to 100 parts by weight of the mixture having the compounding ratio of Example 1. In the same manner as in Example 1, a plate-like molded product was obtained. Table 2 shows the evaluation results of the obtained molded articles.

(Example 12) A plate-like molded product was obtained in the same manner as in Example 1 except that 10 parts by weight of the methacrylic resin (C-1) was further added to the mixture obtained in the mixing ratio of Example 1. .
Table 2 shows the evaluation results of the obtained molded articles.

Comparative Example 1 Rubber-reinforced styrene resin (B
-1) only using a 40 mm extruder and cylinder temperature 2
A pellet was obtained by melt-kneading at 50 ° C., and a pellet was obtained in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained molded articles.

Example 13 Instead of the rubber-reinforced styrene resin (B-1), a rubber-reinforced styrene resin (B-
A plate-shaped molded product was obtained in the same manner as in Example 1, except that the mixing ratio was changed to the one shown in Table 3 using 3). Table 3 shows the evaluation results of the obtained molded articles.

(Comparative Example 2) A plate-like material was prepared in the same manner as in Comparative Example 1 except that the rubber-reinforced styrene resin (B-3) was used instead of the rubber-reinforced styrene resin (B-1) of Comparative Example 1. A molded product was obtained. Table 3 shows the evaluation results of the obtained molded articles.

Example 14 The molded article obtained in Example 1 was subjected to an accelerated exposure test with a sunshine weatherometer for 500 hours. As a result of visually observing the gloss before and after the exposure test, no difference was observed.

(Example 15) The molded article obtained in Example 1 was subjected to a pencil scratch test according to JIS K5400. As a result of the test, the molded product had a pencil hardness of HB.

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

As described above, since the thermoplastic resin composition of the present invention has an excellent balance of heat resistance, impact resistance, moldability, and the like, it can be used for members such as vehicle articles, electric articles, and office supplies. It is suitable as.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 33:12) (C08F 220/14 222: 40 212: 08)

Claims (3)

[Claims] (A) methyl methacrylate units 70 to 9
9% by weight, 1 to 15% by weight of an N-substituted maleimide compound unit and 0 to 15 of other monomer units copolymerizable therewith.
1 to 70 parts by weight of a methacrylic polymer consisting of
(B) A thermoplastic resin composition comprising 99 to 30 parts by weight of a rubber-reinforced styrene resin. 2. A methacrylic polymer (A) comprising 70 to 98% by weight of methyl methacrylate unit, 1 to 15% by weight of N-cyclohexylmaleimide unit and 1 to 15% by weight of styrene unit.
2. The thermoplastic resin composition according to claim 1, which is a copolymer comprising 15% by weight. 3. The composition according to claim 1, further comprising an organic phosphorus compound in an amount of 0.005 to 1 part by weight based on 100 parts by weight of the total amount of the methacrylic polymer (A) and the rubber-reinforced styrene resin (B). The thermoplastic resin composition according to claim 1, wherein: