JPH07196887A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin composition having excellent permanent antistatic properties, impact resistance and mechanical characteristics. CONSTITUTION:10-50wt.% rubber-containing graft copolymer is mixed with 50-89wt.% rigid polymer having a weight-average molecular weight of 50,000 to 100,000 and 50-1wt.% epihalohydrin copolymer, or 100 pts.wt. of the obtained thermoplastic resin composition is mixed with 0-15 pts.wt. homopolymer of an alkyl unsaturated carboxylate monomer or copolymer of this monomer with other vinyl monomer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention has an excellent permanent antistatic property,
The present invention relates to a thermoplastic resin composition having impact resistance and mechanical properties, which is suitable for OA equipment and housings of general household appliances.

[0002]

BACKGROUND OF THE INVENTION Since styrene resins have a good balance of mechanical properties, excellent moldability, and are inexpensive, they are used in household electrical appliances, automobile parts, furniture, etc. Widely used in various fields. Particularly in recent years, with the development of industries such as office automation equipment and office equipment, the demand as a supporting material for housing materials and electric parts has increased, and not only mechanical properties such as impact strength, but also antistatic properties, etc. There is a strong demand.

However, most of the styrene resins show a relatively slow rate of static charge annihilation and have a high surface resistivity, so that they have the drawback of easily adhering dust and the like.
It has been difficult to use in applications that require the rapid disappearance of electrostatic charges.

Therefore, various methods have been proposed for imparting antistatic properties to styrene resins. As a conventional antistatic method, there is a method of kneading or spraying an antistatic agent with a thermoplastic resin, and in the case of a molded article made of a kneaded resin of the former antistatic agent, it is present on the surface thereof. If the antistatic agent is removed by washing with water, rubbing, etc., the antistatic property will be lost, but the antistatic agent contained in the inside of the molded body bleeds to part of the surface to supplement it. . However, ABS resin, HIPS
A styrene resin such as a resin has a problem that the antistatic agent does not easily bleed from the inside to the surface. Also, the latter method of spraying the antistatic agent is very simple,
Since it has a drawback that the antistatic property is more likely to be lost than the former, it is not suitable for applications requiring a long-lasting antistatic effect.

Although a method of kneading a conductive inorganic substance such as carbon fiber or carbon black into a thermoplastic resin has been put into practical use, the color tone is limited to black although the antistatic effect is persistent, and the Izod impact The strength is significantly reduced.

On the other hand, recently, a method of imparting a durable antistatic effect by a method based on a polymer alloy with a conductive polymer has been proposed. For example, JP-A-61-1
185557, JP 62-25164, JP 6
No. 2-273247 and JP-A No. 64-1748 disclose a method of adding an epihalohydrin-based polymer such as epichlorohydrin rubber. Further, a method of adding a polyamide elastomer to JP-A-60-23435 and JP-A-4-309547 is disclosed in JP-A-4-19.
No. 8250 and JP-A-4-218555 disclose a method of imparting an antistatic property to a styrene resin by adding a copolymer of ethylene oxide and propylene oxide or a homopolymer of polyethylene oxide.

OA equipment, home electric appliances and the like have been improved year by year, and accordingly, more sophisticated computerization has been achieved. Semiconductor chips typified by many ICs are used as the heart of this computerization.
Many of these are extremely disliked by the electric charges that cause short circuits and the dust attracted by the electric charges, so that a higher antistatic property is required for the housing member that covers the semiconductor chip. It was However, a satisfactory antistatic effect cannot be obtained by the conventional methods listed above.

[0008]

That is, the present invention relates to a rubber-containing graft copolymer of 10 to 50% by weight, a hard polymer having a weight average molecular weight of 50,000 to 100,000 and an epihalohydrin copolymer. A thermoplastic resin composition having an excellent permanent antistatic property, which is characterized by containing 50 to 1% by weight of a polymer, and 100 parts by weight of the thermoplastic resin composition, and an unsaturated carboxylic acid alkyl ester monoester. 0 to 1 homopolymer of copolymer or copolymer with other vinyl monomer
The present invention provides a thermoplastic resin composition excellent in permanent antistatic property, which is characterized by being mixed in an amount of 5 parts by weight.

Examples of the rubber-like polymer in the rubber-containing graft copolymer used as a constituent of the thermoplastic resin composition of the present invention include polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, polychloroprene, Examples thereof include acrylic rubber, ethylene-propylene rubber, ethylene-propylene-diene monomer rubber, and styrene-vinyl acetate copolymer. Among them, polybutadiene, butadiene-styrene copolymer,
Acrylic rubber, ethylene-propylene rubber, ethylene-
Propylene-diene monomer rubber is preferred.

The monomer to be grafted on the rubber is
Aromatic vinyl monomers such as styrene, α-methylstyrene and p-methylstyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and unsaturated carboxylic acid alkyl ester monomers and maleimide monomers. A quantity etc. can be used. Of these, one or more monomers can be selected and used, but preferably rubber-modified graft copolymers containing an aromatic vinyl monomer as an essential component in consideration of reactivity and physical properties. Coalescence is desirable.

Specific examples of the above rubber-modified graft copolymer include rubber-reinforced polystyrene (HIPS), acrylonitrile-butadiene-styrene terpolymer (AB).
S resin), acrylonitrile-butadiene-α-methylstyrene terpolymer, acrylonitrile-acrylic rubber-styrene terpolymer (AAS resin), acrylonitrile-ethylene-propylene copolymer rubber-styrene terpolymer An example is a combination (AES resin). Each of these may be used alone, or in the case of a polymer having good compatibility, it may be used as a mixture of two or more kinds, if necessary.

The hard polymer which is a constituent component of the present invention includes vinyl cyanide monomers, aromatic vinyl monomers and (co) polymers of other monomers copolymerizable therewith. is there. Examples of other copolymerizable monomers include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
Unsaturated carboxylic acid alkyl ester monomers such as butyl methacrylate and hydroxymethacrylate, maleimide, N-methylmaleimide, N-ethylmaleimide, N
Examples include maleimide-based monomers such as -propylmaleimide, N-cyclohexylmaleimide and N-phenylmaleimide.

The hard polymer which is a constituent of the present invention includes polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-α-methylstyrene copolymer,
Examples thereof include acrylonitrile-styrene-N-phenylmaleimide terpolymer and acrylonitrile-α-methylstyrene-N-phenylmaleimide terpolymer.

The weight average molecular weight of the hard polymer which is a constituent of the present invention is 50,000 to 100,000. When the weight average molecular weight is less than 50,000, physical properties such as impact strength and flexural modulus are poor. When the weight average molecular weight exceeds 100,000, antistatic performance is poor. The weight average molecular weight described here is the one converted into the weight average molecular weight of polystyrene by gel permeation chromatography.

The epihalohydrin-based copolymer used as a constituent of the thermoplastic resin composition of the present invention is
General formula

[0016]

[Chemical 1]

(In the formula, X is a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom or a bromine atom,
Most preferably, it is a chlorine atom. ) Are homopolymers of the monomers represented by the above) or copolymers of the monomers with various copolymerizable monomers having an oxirane ring.

Examples of various copolymerizable monomers having such an oxirane ring are glycidyl ethers, monoepoxides of dienes and polyenes, glycidyl esters and alkylene oxides. Specific examples of such a copolymerizable monomer include vinyl glycidyl ether, isopropenyl glycidyl ether, butadiene monooxide, chloroprene monooxide, 3,4-epoxy-1-pentene, glycidyl acrylate, 1,2-epoxy-3. ，
3,3-trichloropropane, phenylglycidyl ether, ethylene oxide, propylene oxide and trichlorobutylene oxide. Preferred copolymerizable monomers are alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide, 3,4-epoxy-1-pentene, 1,2-epoxy-3,3,3-trichloropropane, and the like. Among them, ethylene oxide, propylene oxide or a mixture thereof is more preferable, and ethylene oxide is most preferable.

Suitable epihalohydrin copolymers are either commercially available or can be prepared using known techniques from known commercially available monomers. Generally, the epihalohydrin-based copolymer is about 1 to 99 mol%.
Of epihalohydrin and about 99 to 1 mol% of the copolymerizable compound having the oxirane ring shown above. More preferably, the copolymer comprises about 1 to 50 mol% epihalohydrin and about 50 to 99 mol% of a copolymerizable compound having an oxirane ring. Most preferably, the copolymer comprises from about 1 to 20 mol% epihalohydrin and about 9
It is composed of a copolymerizable compound having 9 to 80 mol% of oxirane ring. The most preferable epihalohydrin copolymer is a copolymer of epichlorohydrin and ethylene oxide.

The viscosity of the epihalohydrin copolymer in the thermoplastic resin composition of the present invention is not particularly limited,
The reduced viscosity is preferably 10 or less. The reduced viscosity as used herein is measured by a Ubbelohde viscous tube in which a solution of solvent: toluene and concentration: 0.25% by weight is placed in a constant temperature bath at 25 ° C. The formula for calculating the reduced viscosity is as follows.

Ηsp / C = (t / t ₀ −1) /0.217 (where, t is the number of seconds of passage of the sample solution, t ₀ is the number of seconds of passage of the solvent.) The thermoplastic resin of the present invention In the composition, when the amount of the rubber-containing graft copolymer is less than 10% by weight, the impact strength of the resin composition is poor, and when the amount of the rubber-containing graft copolymer exceeds 50% by weight. However, the resin composition is inferior in molding processability such as fluidity and is not practical. When the amount of the hard polymer is less than 50% by weight, the flexural modulus of the resin composition becomes small, and the amount of the hard polymer is 89%.
When it exceeds the weight%, the impact strength of the resin composition becomes poor and it becomes unpractical. When the amount of the epihalohydrin copolymer is less than 1% by weight, the surface specific resistance of the product obtained from the resin composition becomes large and the antistatic property deteriorates, and the amount of the epihalohydrin copolymer becomes 50% by weight. If it exceeds%, the flexural modulus of the resin composition becomes small and it becomes impractical.

A homopolymer of an unsaturated carboxylic acid alkyl ester monomer used as a constituent of the present invention or a copolymer with another vinylic monomer (hereinafter referred to as an unsaturated carboxylic acid alkyl ester monomer Examples of the unsaturated carboxylic acid alkyl ester monomer in the polymer abbreviated form) include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and hydroxy methacrylate. Further, other vinyl monomers copolymerizable with these unsaturated carboxylic acid alkyl ester monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, nucleus-substituted methylstyrene, and chlorostyrene. And vinyl cyanide monomers such as acrylonitrile and methacrylonitrile.

The unsaturated carboxylic acid alkyl ester monomer preferably accounts for at least 40% by weight in the copolymer. The unsaturated carboxylic acid alkyl ester monomer-containing polymer enhances the compatibility between the styrene resin and the epihalohydrin copolymer and has an effect of preventing the layered peeling of the molded product during insufficient kneading. 40% by weight of unsaturated carboxylic acid alkyl ester monomer in the copolymer
If it is less, the effect is less likely to be exhibited.

The amount of the unsaturated carboxylic acid alkyl ester monomer-containing polymer is preferably within 15 parts by weight with respect to 100 parts by weight of the thermoplastic resin composition of the present invention.
When the amount of the unsaturated carboxylic acid alkyl ester monomer-containing polymer exceeds 15 parts by weight, the impact resistance is deteriorated and the practicality is deteriorated.

The thermoplastic resin composition of the present invention comprises a rubber-containing graft copolymer, a hard polymer and an epihalohydrin copolymer in the amounts described above, in a Banbury mixer, melt blending, extruding and kneading. It can be adjusted by various methods such as meat. At this time, impact modifier, pigment,
Other known additives such as a lubricant, a stabilizer, an antioxidant, an antistatic agent and a filler may be mixed.

[0026]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist. In the following, "part" is "part by weight" and "%" is "% by weight".
Indicates. Examples 1 to 6 and Comparative Examples 1 to 6 As a rubber-containing graft copolymer, an ABS graft in which acrylonitrile and styrene are grafted with a polybutadiene rubber having a composition shown in the following table obtained by a known emulsion polymerization method as a substrate. Acrylonitrile and styrene-grafted AES graft polymers were used with the polymer and EPDM rubber as substrates, and acrylonitrile and styrene-grafted AAS graft polymers were used with polybutyl acrylate rubber as substrates.

[0027]

[Table 1]

As the hard polymer, an AS resin having a composition shown in Table 2 obtained by a known suspension polymerization method was used.

[0029]

[Table 2]

The weight average molecular weight is GP manufactured by Tosoh Corporation.
C HLC-802A (column used: TSK gel
GMHXL) was used and measured by polystyrene conversion.

The epihalohydrin-based copolymer has a rational formula:

[0032]

[Chemical 2]

A copolymer of epichlorohydrin and ethylene oxide represented by the following formula was used.

-Epichlorohydrin / ethylene oxide: 10 / 90-Reduced viscosity ηsp / C: 5.1 (reduced viscosity is toluene at a concentration of 0.25% in a constant temperature bath at 25 ° C) (Measured with a Ubbelohde viscosity tube in) as an unsaturated carboxylic acid alkyl ester-containing polymer,
Acrypet MD manufactured by Mitsubishi Rayon Co., Ltd. was used.

The blending amounts of these respective components are shown in Table 3. Further, 0.5 part of magnesium stearate as a lubricant was added thereto to obtain a blend. Charge the blends into a Banbury mixer heated to 140 ° C,
Melt and knead, take out when the mixture reaches 190 ° C., immediately form a sheet with a mixing roll, cool,
It was crushed into pellets.

These pellets were fed into the hopper of the injection molding machine under the following conditions depending on the physical properties to be measured, melted in the plasticizing cylinder, and injected into the injection molding die under the following conditions: The physical properties were measured. ： Izod impact strength, flexural modulus: ・ Molding: made by Japan Steel Works, Ltd. 4oz injection molding machine, cylinder setting temperature 220 ℃, mold 50 ℃,
The test piece was molded and measured. -Measurement method: Izod impact strength: ASTM D-256 compliant method (1/8 "notch, 23 ° C) Bending elastic modulus: ASTM D-790 compliant method Surface resistivity: -Molding: manufactured by Japan Steel Works, Ltd. Using a 2oz injection molding machine, set the cylinder temperature at 220 ° C and the mold at 50 ° C.
A test piece of 100 mm × 100 mm × 3 mm was molded and measured.・ Sample preparation: Immediately after molding, thoroughly wash the test piece with distilled water. After that, remove the water on the surface and adjust the relative humidity to 50.
%, 23 ° C. for 2 days.

Measurement method: Surface resistivity: ASTM D-257 compliant method Device: High resistance meter (manufactured by Yokogawa Hewlett Packard Co.) Applied voltage: 1000 V Applied time: 60 seconds The measurement results are shown in Table 3. It was as shown.

[0038]

[Table 3]

[0039]

[Table 4]

As is clear from the data in Table 3, the molded articles obtained from the thermoplastic resin compositions of the present invention (Examples 1 to 6) are excellent in both mechanical properties such as impact strength and electrical conductivity. there were. On the other hand, when the polystyrene-converted weight average molecular weight of the hard polymer is outside the range of the weight average molecular weight of the present invention (Comparative Examples 1 and 2), the compounding amount of the rubber-containing graft copolymer is specified by the present invention. When it is less than the amount (Comparative Example 3), when the amount of the epihalohydrin-based copolymer compounded is less than the amount specified in the present invention (Comparative Example 4) and when it is more than that (Comparative Example 5), unsaturated carvone is used. When the amount of the acid alkyl ester monomer-containing polymer is more than the amount specified in the present invention (Comparative Example 6), the effects intended by the present invention (excellent permanent antistatic property, impact resistance, mechanical properties, (Provision of a resin composition having characteristics) cannot be achieved.

[0041]

Since the thermoplastic resin composition of the present invention has excellent permanent antistatic property, impact resistance and mechanical properties,
It can be used for housing of office automation equipment and general household appliances.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location C08L 63/00 NJN (72) Inventor Tsutomu Yoshitomi No. 14 of 525, Oki, Ube, Yamaguchi Prefecture Ube Saikon Ube Plant Co., Ltd. (72) Inventor Junhisa Akahisa Oki, Ube, Yamaguchi Prefecture 14 No. 525, Okiyama, Ube Ubi Plant, Ube Cycon Co., Ltd.

Claims (8)

[Claims] 1. A hard polymer 5 having a weight average molecular weight of 50,000 to 100,000 in 10 to 50% by weight of a rubber-containing graft copolymer.
0-89% by weight and epihalohydrin-based copolymer 50-
A thermoplastic resin composition having an excellent permanent antistatic property, which is characterized by containing 1% by weight. 2. The thermoplastic resin composition 10 according to claim 1.
0 to 15 parts by weight of a homopolymer of an unsaturated carboxylic acid alkyl ester monomer or a copolymer with another vinyl-based monomer is blended in an amount of 0 to 15 parts by weight. A thermoplastic resin composition having excellent properties. 3. The hard polymer is a copolymer of a vinyl cyanide monomer and an aromatic vinyl monomer, or a copolymer of another monomer copolymerizable therewith. 2. The thermoplastic resin composition as described in 2. 4. The thermoplastic resin composition according to claim 1, wherein the hard polymer is an acrylonitrile-styrene copolymer (AS resin). 5. The rubber-containing graft copolymer is an acrylonitrile-butadiene-styrene terpolymer (AB).
S resin), The thermoplastic resin composition according to claim 1 or 2. 6. The thermoplastic resin composition according to claim 1, wherein the rubber-containing graft copolymer is an acrylonitrile-acrylic rubber-styrene terpolymer (AAS resin). 7. The thermoplastic resin composition according to claim 1, wherein the rubber-containing graft copolymer is an acrylonitrile-ethylene-propylene copolymer rubber-styrene terpolymer (AES resin). 8. The thermoplastic resin composition according to claim 1, wherein the epihalohydrin copolymer is a copolymer of epichlorohydrin and ethylene oxide.