JP2634844B2 - Impact resistant resin composition having antistatic properties - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having antistatic performance. More specifically, it relates to a thermoplastic styrene resin composition having excellent impact resistance and having permanent antistatic performance.

[Conventional technology and problems]

High impact polystyrene (hereinafter referred to as HIPS)
Alternatively, rubber-reinforced thermoplastic resin known as ABS resin has excellent moldability, dimensional stability method, impact resistance, and electrical insulation, so it is used as a molding material for a wide range of applications, including electrical products and office equipment Have been. However, HIP
S and ABS resins, like other plastics for molding, are easily charged easily, so that dust and dirt adsorb on the surface of the molded product and impair the appearance of the product, and the molded product is a component of electrical products In such a case, there is a problem that the device cannot function normally due to the attached dust and the like.

As a means for solving such a problem, a method conventionally used is (1) a method of applying an antistatic agent to the surface of a molded article (2), and kneading the antistatic agent into a thermoplastic resin material for molding. Method (a) is a method of chemically modifying the structure of a resin.

However, the method (1) not only requires a step of applying an antistatic agent separately from the molding step, but also has a disadvantage that the antistatic effect is reduced due to aging or washing. In addition, the method (2) solves the problem of productivity reduction in that no coating step is required,
There are problems such as contamination of the molded product surface due to bleed out of the kneaded antistatic agent, deterioration of the appearance, and deterioration of the antistatic effect due to aging of the kneaded antistatic agent.

Further, the method (3) is, for example, a method of mixing a styrene resin modified with a carboxyl group and a polyalkylene oxide or a derivative thereof (US Pat. No. 29
No. 12413, German Patent No. 3203488, JP
59-142242), a method of graft-polymerizing a vinyl monomer onto a hydrophilic rubbery polymer obtained by copolymerizing a conjugated diene or acrylate and a vinyl monomer having an alkylene oxide group (particularly, JP-A-55-36237), a mixture of a polyetheramide copolymer and a copolymer obtained by grafting a (meth) acrylic acid ester monomer or the like to a rubber mass (JP-A No. 62-11759), Composition comprising a copolymer of a styrene resin, a vinyl monomer and a monomer containing an alkylene oxide group, and a metal salt dissolved in the copolymer (JP-A-62-158742) A diene rubber latex, a graft copolymer obtained by graft polymerization of a vinyl monomer and a monomer containing an alkylene oxide group, and a sulfonic acid or a carboxylic acid having a perfluoroalkyl group. A resin composition consisting valent metal salt (JP 62-207352 JP) have been proposed.

However, the aforementioned U.S. Pat.No. 2,912,413,
In the methods disclosed in German Patent No. 3203488 and JP-A-59-142242, since a hydrophilic polyalkylene oxide is used as a means for imparting antistatic properties, the effect is greatly affected by the humidity of the environment. In addition, the effect does not appear unless a sufficient amount of polyalkylene oxide is added,
As a result, there has been a problem that the impact strength and heat resistance of the composition are reduced. JP-A-55-36237, JP-A-6-23737
The methods disclosed in Japanese Patent Application Laid-Open No. 2-11759, while both realizing semi-permanent antistatic properties, are expensive hydrophilic monomers (alkylene oxide group-containing vinyl monomers) and hydrophilic block polymers (polyetheramides). (Copolymer), the production process becomes complicated, and there is a problem that the finally obtained composition becomes extremely expensive. JP-A-62-158742, JP-A-62-20
Although the method of JP 7352 Publication achieves both good permanent antistatic properties, it is necessary to use a relatively large amount of an alkylene oxide group-containing monomer, and it is difficult to obtain a composition having a high impact strength. There was a problem.

[Means to solve the problem]

The present inventors have conducted intensive studies with the aim of providing a thermoplastic resin having permanent antistatic properties, excellent impact resistance, and low cost. As a result, an acid containing a carboxyl group or an acid anhydride group has been obtained. By blending a modified rubber-reinforced polystyrene-based resin with a polyether having a specific molecular weight and a specific organic or inorganic metal salt, a composition excellent in heat resistance while at the same time achieving the above object can be obtained. Thus, the present invention has been completed.

That is, the present invention relates to (A) a rubber-reinforced vinyl aromatic polymer 100 modified with a monomer containing a carboxyl group.
Parts by weight, (B) having an average molecular weight of 10
5-20 parts by weight of polyether of more than 10,000, (Wherein, R represents -H or -CH _3, X is -O-, n is an integer determined by the average molecular weight.) And (C), and characterized by comprising a metal salt which forms a solid solution with (B) An antistatic and impact-resistant resin composition.

In the present invention, (B) the general formula A polyether having an average molecular weight of 100,000 or more (hereinafter, referred to as
It is called a compound. ) And (C) a metal salt which forms a solid solution with the above (B) (hereinafter referred to as a metal salt) to form a solid polymer electrolyte, and the composition of the present invention is excellent in being not affected by humidity. It plays a role of imparting an excellent antistatic property.
On the other hand, (A) a rubber-reinforced vinyl aromatic polymer modified with a monomer containing a carboxyl group (hereinafter, referred to as an acid-modified rubber-reinforced resin) and the compound are appropriately bonded by hydrogen bonding. It is considered that a compatible system is formed, and as a result, good antistatic properties are imparted without impairing the mechanical properties of the acid-modified rubber-reinforced resin. Therefore, in the present invention, the desired object cannot be achieved even if any of the above-mentioned acid-modified rubber reinforcing resin compound and metal salt are missing.

The acid-modified rubber reinforcing resin used in the present invention is a mixture of one or more vinyl monomers having a vinyl aromatic monomer as a main component and a vinyl monomer having a carboxyl group in the molecule. And a polymer obtained by graft copolymerization with a rubbery polymer. The carboxyl group in the present invention may be an anhydrous carboxyl group. The amount is 10
When the content of the carboxyl group-containing monomer in 0 parts by weight is 1
It is preferable to adjust so as to be in a range of about 20% by weight. When the content of the carboxyl group-containing monomer is less than 1% by weight, the compatibility with the compound is deteriorated, and the impact strength is reduced. Further, the content of the carboxyl group-containing monomer,
If it is at least 20% by weight, the fluidity of the composition will be poor and it will be difficult to use it as a molding material. As the carboxyl group-containing monomer, a vinyl monomer having a carboxyl group or a carboxyl anhydride group such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid is used. Further, as the vinyl aromatic monomer used together with the carboxyl group-containing monomer, styrene, vinyl aromatic monomers such as α-methylstyrene alone, and copolymerizable with these monomers A small amount of monomers, for example, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and (meth) acrylate monomers such as methyl methacrylate and butyl acrylate can be used in combination.
Further, as the rubbery polymer, ordinary rubbery polymers such as polybutadiene, styrene-butadiene copolymer rubber (SBR), and styrene-acrylonitrile copolymer rubber (NBR) can be used.

The polymerization method of the acid-modified rubber-reinforced resin is not particularly limited,
The vinyl monomer and the vinyl monomer having a carboxyl group may be graft-copolymerized in the presence of the rubbery polymer according to a conventional method such as bulk polymerization, bulk / suspension polymerization, emulsion polymerization and the like. Further, in addition to the method of direct polymerization as described above, a method of preparing a rubber-reinforced vinyl aromatic polymer having a high rubber content and a high carboxyl group content in advance and mixing it with a vinyl aromatic polymer, Modifications such as a method of mixing an aromatic polymer with a vinyl aromatic polymer having a high carboxyl group content can also be employed.

Specific examples of the compound used in the present invention include polyethylene glycol and polyethylene oxide (R = -H, X =
—O—), polypropylene glycol, polypropylene oxide (R = —CH ₃ , X = —O—) and the like. Polyethylene glycol or polyethylene oxide is preferred from the viewpoint of the antistatic property and impact strength of the composition. These polymer compounds can form an appropriate compatible system with the acid-modified rubber reinforcing resin by hydrogen bonding, but in order to achieve the object of the present invention, it is necessary that the average molecular weight is 100,000 or more. It is. When the average molecular weight is less than 10,000, the antistatic effect is not sufficient, or it is necessary to add a large amount to obtain the required antistatic effect. Since it is low in brittleness, it is impossible to achieve both antistatic properties and mechanical strength. The average molecular weight is preferably at least 300,000. When the average molecular weight is 100,000 or more, particularly 300,000 or more, the finally obtained composition has not only an antistatic property but also a large impact strength and elongation of the acid-modified rubber reinforced resin as the base resin. It can be a useful molding material having excellent mechanical strength exceeding the above. Further, the amount of use is preferably 5 to 20 parts by weight based on 100 parts by weight of the acid-modified rubber reinforced resin. If the amount is less than 5 parts by weight, the antistatic property of the finally obtained composition is not sufficient, and if it is more than 20 parts by weight, the impact strength of the finally obtained composition is undesirably reduced.

Examples of the metal salt used in the present invention include “Chemistry”, 38, 6 pages 418-426 (1983) or Solid State.
Ionics (Solid State Ionics), vol 9 & 10,7
45-754 pages (1983), Journal. of. Journal of Physical Chemistry, vol
89 (6), pages 987 to 991 (1985) and the like. Specifically, lithium chloride, lithium bromide, sodium bromide, lithium iodide, sodium iodide, lithium borohydride, sodium borohydride,
Lithium boron fluoride, sodium boron fluoride, potassium boron fluoride, lithium tetraphenylborate, sodium tetraphenylborate, potassium tetraphenylborate, lithium thiocyanate, sodium thiocyanate,
Potassium thiocyanate, lithium perchlorate, sodium perchlorate, potassium perchlorate, lithium trifluoroacetate, sodium trifluoroacetate, potassium trifluoroacetate, lithium trifluoromethanesulfonate, sodium trifluoromethanesulfonate, trifluoromethane Examples thereof include potassium sulfonate, lithium hexafluorophosphate, sodium hexafluorophosphate, potassium hexafluorophosphate, and lithium acetate.
The solid solution of these metal salts with the compound can be confirmed by means such as X-ray and thermal analysis.

The above metal salts may be used alone or in combination of two or more. The content of these metal salts is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the acid-modified rubber reinforcing resin. Consumption
If the amount is less than 0.1 part by weight, the antistatic property of the composition is not sufficient even if the amount of compound B added is as described above, and if it is 5 parts by weight or more, no further improvement in the antistatic property is observed. Also, it is not preferable because the mechanical strength is reduced.

The production method of the present invention / resin composition is not particularly limited,
If the metal salt has a high melting point, dissolve the compound and the metal salt in a common solvent (water, alcohol, DMF, etc.) in advance, remove the solvent to form a solid solution of the compound and the metal salt, and then add Mixing with a modified rubber reinforcing resin is preferred because the metal salt is uniformly dispersed and a good antistatic effect is exhibited. Examples of the apparatus used include commonly used kneaders such as a Banbury mixer, a roll, and an extruder.

Further, the resin composition of the present invention, an antioxidant, a light stabilizer,
Lubricants, coloring dyes, etc.
And other resins can be blended.

〔The invention's effect〕

The resin composition thus obtained has excellent antistatic properties and impact resistance, and is useful as a molding material for housings of various products including electric appliances, office equipment, and the like.

〔Example〕

Hereinafter, the present invention will be described based on examples. The physical properties were measured according to the following procedures.

(I) Preparation of a test piece for measuring physical properties: The pellets obtained in Examples and Comparative Examples were mixed with an injection molding machine at a cylinder temperature of 220 ° C. at a cylinder thickness of 1/8 inch and a 1/8 inch plate. A 1/4 inch thick test piece was made.

(Ii) Measurement of physical properties; Izod impact strength: based on ASTM D256. (Uses 1/4 inch thick test piece) Tensile strength, elongation: Conforms to ASTM D638. (Uses 1/8 inch thick test piece) Flexural modulus: Conforms to ASTM D790.

 (Uses 1/4 inch thick test piece) Vicat softening point: Conforms to ASTM 1525.

 Surface resistivity: Measured under the following conditions using a 1/8 inch thick flat plate.

A) After molding, the condition was adjusted for 48 hours at 23 ° C and 50% RH, and then measured.

B) After molding, immerse in running water for 10 minutes to remove moisture on the surface. The condition was measured for 48 hours and then measured.

 In addition, a super-insulation meter SM-10E manufactured by Toa Denpa Kogyo Co., Ltd. was used for the measurements in a) and b).

Further, the number of parts described below indicates parts by weight, and the percentage indicates weight percent.

(Reference example)

Production of Acid-Modified Rubber Reinforced Resin and Rubber Reinforced Resin (i), Production of Acid-Modified Rubber Reinforced Resin (A-1) Polybutadiene (NF35A manufactured by Asahi Kasei Corporation) is dissolved in a monomer mixture of styrene and methacrylic acid, By bulk polymerization method, rubber content 7.5%, methacrylic acid content 3
% Of an acid-modified rubber-reinforced polystyrene (A-1).
The physical properties of this polymer alone were a notched Izod impact strength with a notch of 7 kg.cm/cm, a tensile strength of 340 kg / cm ² , an elongation of 20%, a flexural modulus of 26,000 kg / cm ² , and a Vicat softening point of 113 ° C.

(Ii), Production of Rubber Reinforced Resin (A-2) In the production of (A-1), polymerization was carried out without using methacrylic acid to obtain a rubber reinforced polystyrene (A-2) having a rubber content of 7.5%. The physical properties of this polymer, Notsuchi with Aizotsuto impact strength 8Kg.Cm/cm, tensile strength 430 kg / cm ^2, elongation 20%, flexural modulus 26,000kg / cm ^2, Pikatsuto softening point 105
° C.

In the examples and comparative examples of the present invention, the following polyethylene glycol or polyethylene oxide was used.

PEG-6,000: polyethylene glycol having a molecular weight of 7,500.

PEG-20,000: polyethylene glycol having a molecular weight of 20,000.

PEG-50,000: polyethylene glycol having a molecular weight of 50,000.

PEO-30 (manufactured by Meisei Chemical Co., Ltd., trade name: Alcox)
E-30): polyethylene oxide having a molecular weight of 300,000.

Example 1 100 parts of acid-modified rubber reinforced resin (A-1), PEO-30 10
And 2 parts of potassium thiocyanate were fed to a vented 30 mm twin screw extruder, extruded at a resin temperature of 220 ° C., and pelletized. The physical properties of the composition were measured by the methods described above. Table 1 shows the results.

Comparative Example 1 A composition was prepared in the same manner as in Example 1 except that PEG-20,000 was used instead of PEO-30 in Example 1, and the physical properties of the obtained composition were measured. Table 1 shows the results.

Comparative Example 2 A composition was prepared in the same manner as in Example 1 except that (A-2) was used instead of (A-1) in Example 1, and the physical properties of the composition were measured. Table 1 shows the results.

Comparative Example 3 A composition was prepared in the same manner as in Example 1 except that PEG-6,000 was used instead of PEO-30 in Example 1, and the physical properties of the composition were measured. Table 1 shows the results.

Comparative Example 4 Example 1 except that PEO-30 in Example 1 was not used.
And the physical properties of the composition were measured. Table 1 shows the results.

Comparative Example 5 A composition was prepared in the same manner as in Example 1 except that potassium thiocyanate in Comparative Example 1 was not used, and the physical properties of the composition were measured.

 Table 1 shows the results.

Comparative Example 6 100 parts of pure water was placed in a vessel equipped with a stirring blade, and PEG-50,0
Then, 100 parts of 00 and 20 parts of sodium iodide were added, and it took 5 hours while stirring at room temperature to obtain a uniform viscous liquid. The liquid was taken out of the container and dried under high vacuum conditions at 95 ° C. for 2 hours and at 150 ° C. for 10 hours.

Solid solution of PEG-50,000 and sodium iodide obtained 12
Parts (10 parts of PEG-50,000, 2 parts of sodium iodide)
And 100 parts of (A-1) used in Example 1 were blended in the same mixing ratio and method as in Example 1, and the physical properties of the obtained composition were measured. Table 1 shows the results.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C08L 71:02)

Claims (1)

(57) [Claims] (1) 100 parts by weight of a rubber-reinforced vinyl aromatic polymer modified with a monomer containing a carboxyl group, and (B) a polymer represented by the following general formula and having an average molecular weight of 100,000 or more. 5-20 parts by weight of ether, (Wherein, R represents -H or -CH _3, n is an integer determined by the average molecular weight.) Is characterized by comprising a, and (C) (B) a metal salt from 0.1 to 5 parts by weight of a solid solution charge Inhibitory resin composition.