JP3464258B2 - Thermoplastic resin composition - Google Patents

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, according to the present invention, 70 to 99% by weight of a styrene resin and a reduced viscosity (ηsp / C) are used.
With respect to 100 parts by weight of a thermoplastic resin composition consisting of 1 to 30% by weight of an epihalohydrin-based copolymer having an amount of more than 0.5 and 10 or less, a homopolymer of an unsaturated carboxylic acid alkyl ester monomer or another It is intended to provide a thermoplastic resin composition having an excellent permanent antistatic property, which is characterized by containing 0 to 15 parts by weight of a copolymer with a vinyl monomer.

Examples of the styrene resin used as a constituent component of the thermoplastic resin composition of the present invention include polystyrene, rubber-reinforced polystyrene (HIPS), acrylonitrile-styrene copolymer (SAN resin), and acrylonitrile-α-methylstyrene copolymer. Polymer, acrylonitrile-butadiene-styrene terpolymer (ABS resin),
Acrylonitrile-butadiene-α-methylstyrene terpolymer, acrylonitrile-acrylic rubber-styrene terpolymer (AAS resin), acrylonitrile-ethylene-propylene copolymer rubber-styrene terpolymer (AES resin) ) And the like, and a resin obtained by copolymerizing a monomer such as an unsaturated carboxylic acid alkyl ester compound or a maleimide compound copolymerizable therewith can also be used. 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 epihalohydrin-based copolymer used as a constituent of the thermoplastic resin composition of the present invention is
General formula

[0011]

[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 epihalohydrin-based copolymer in the thermoplastic resin composition of the present invention has a reduced viscosity of 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 / to-1) /0.21
7 (where t is the number of seconds of passage of the sample solution, t is the number of seconds of passage of the solvent.) When the reduced viscosity of this epihalohydrin-based copolymer exceeds 10, the epihalohydrin-based resin in the styrene-based resin is used. The state of dispersion of the copolymer is coarse,
Observation with an electron microscope revealed that a large mass of epihalohydrin-based copolymer was scattered in the styrene-based resin. Therefore, the surface specific resistance of the product obtained from the resin composition is increased, and the antistatic property tends to be deteriorated. On the other hand, when the reduced viscosity of the epihalohydrin-based copolymer is 10 or less, the epihalohydrin-based copolymer is finely dispersed in the styrene-based resin, and the surface resistivity of the product obtained from this resin composition is small, and the antistatic property is low. The performance was very good. Preferred reduced viscosity is more than 0.5
Large is 10 or less.

In the thermoplastic resin composition of the present invention, the amount of the styrene resin is less than 70% by weight based on the total weight of the styrene resin and the epihalohydrin copolymer (hence, the amount of the epihalohydrin copolymer is (Over 30% by weight)
In that case, the flexural modulus of the resin composition tends to be small, which tends to be impractical. On the other hand, when the amount of the styrene resin is more than 99% by weight (therefore, 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 charging Preventability tends to deteriorate.

A homopolymer of an unsaturated carboxylic acid alkyl ester monomer used as a constituent of the present invention or a copolymer with another vinyl-based monomer (hereinafter, the unsaturated carboxylic acid alkyl ester monomer is contained. As the unsaturated carboxylic acid alkyl ester monomer in (hereinafter abbreviated as “polymer”),
Examples thereof 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 is preferably 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 styrene resin and an epihalohydrin copolymer having a specific reduced viscosity in the above-mentioned amounts, such as mixing in a Banbury mixer, melt mixing, extrusion and kneading. Can be adjusted in various ways. 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.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples. Examples 1 to 9 and Comparative Examples 1 to 4 ABS resin (Ube Saikon Co., Ltd.) as a styrene resin
Made, product name "Psycholac EX101"), AES resin (made by Ube Saikon Co., Ltd., product name "UCL AXS S
K10 ") or AAS resin (trade name" Weatherfill MD110 "manufactured by Ube Saikon Co., Ltd.). Tiredness
As polymers containing Japanese carboxylic acid alkyl ester, Mitsubishi
Acrypet MD manufactured by Rayon Co., Ltd. was used.

The epihalohydrin-based copolymer has a rational formula:

[0024]

[Chemical 2]

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

[Table 1]

The reduced viscosity was such that 0.25 g of epihalohydrin type copolymer was taken and toluene was added to each of them to make a total of 100 g, and the mixture was completely dissolved by stirring. This solution was measured with an Ubbelohde viscous tube 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 and t ₀ is the number of seconds of passage of the solvent.) Combination of each of these components The amount was as shown in Table 1. Furthermore, magnesium stearate as a lubricant was added to this.
A blend was obtained by adding 5 parts by weight. 14 of those formulations
The mixture was put into a Banbury mixer heated to 0 ° C, melt-kneaded, taken out when the mixture reached 190 ° C, immediately formed into a sheet with a mixing roll, cooled, pulverized, and pelletized.

These pellets were fed into the hopper of the injection molding machine under the following conditions according to 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-25
6 Governing Law (1/8 ″ Notched, 23 ° C.) Bending Elastic Modulus: ASTM D-790 Governing Law Surface Specific Resistance: ・ Molding: Japan Steel Works 2oz injection molding machine, cylinder set temperature 220 1 ℃ at 50 ℃
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.
%, And conditioned at 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 1. It was on the street.

[0031]

[Table 2]

[0032]

[Table 3]

As is clear from the data in Table 1, the molded articles obtained from the thermoplastic resin compositions of the present invention (Examples 1 to 9) are excellent in mechanical properties such as impact strength and electrical conductivity. there were. On the other hand, when the blending amount of the epihalohydrin-based copolymer is less than the amount specified in the present invention (Comparative Example 1) and when it is more (Comparative Example 2), the reduced viscosity of the epihalohydrin-based copolymer is In the case where it is higher than the specified reduced viscosity of the invention (Comparative Example 3) and when it is smaller (Comparative Example 5), the unsaturated carboxylic acid alkyl ester monomer-containing polymer is more than the amount specified in the present invention (Comparative Example). In 4), the desired effect of the present invention (providing a resin composition having excellent permanent antistatic properties, impact resistance, and mechanical properties) cannot be achieved.

[0034]

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. ⁷ Identification code FI C08L 33:08) C08L 33:08 (72) Inventor Tsutomu Yoshitomi No. 14 of 525, Oki, Ube, Yamaguchi Prefecture Ube Saikon Ube Factory Co., Ltd. (72) Inventor Junhisa Akahoshi, Obe City, Ube Yamaguchi Prefecture, No. 14 at 525, off the coast of Ube, Ube Saikon Co., Ltd. Ube Factory (56) Reference JP-A-7-53845 (JP, A) ( 58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 51/00-51/08 C08L 55/00-55/04 C08L 63/00-63/10

Claims (5)

(57) [Claims] 1. A thermoplastic resin composition comprising 70 to 99% by weight of a styrene resin and 1 to 30% by weight of an epihalohydrin copolymer having a reduced viscosity (ηsp / C) of more than 0.5 and 10 or less . 100 parts by weight of unsaturated calcium
Homopolymers of alkyl borate esters or other vinyl
Do not mix 0 to 15 parts by weight of a copolymer with a nil monomer.
The thermoplastic resin composition excellent in permanent antistatic properties, characterized in that that. 2. The thermoplastic resin composition according to claim 1, wherein the styrene resin is an acrylonitrile-butadiene-styrene terpolymer (ABS resin). 3. The acrylonitrile-acrylic rubber-styrene terpolymer (AAS resin) is used as the styrene resin.
The thermoplastic resin composition according to claim 1, which is 4. The thermoplastic resin composition according to claim 1, wherein the styrene resin is an acrylonitrile-ethylene-propylene copolymer rubber-styrene terpolymer (AES resin). 5. The thermoplastic resin composition according to claim 1, wherein the epihalohydrin-based copolymer is a copolymer of epichlorohydrin and ethylene oxide.