JPH0372659B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an antistatic resin composition having a colorable color tone. Adding carbon black or metal powder has traditionally been done as a way to impart antistatic properties to plastics, but this method impairs the original color tone of the plastics, and also causes a loss of transparency in transparent plastics. There are other problems. On the other hand, as a method of imparting antistatic properties without impairing the original color tone or transparency of plastics,
There is a method of coating or adding an antistatic agent to plastic, but this method can impart surface conductivity to plastic, but it is difficult to impart volume conductivity to plastic. In view of the current situation, the present inventors conducted various studies in order to impart volumetric conductivity without significantly impairing the original color tone of plastics, and as a result, they blended specific fine particles of silicic acid or silicate and a specific compound into synthetic resin. The present invention was achieved by discovering that a resin composition having volume conductivity and a colorable tone can be obtained by doing so. That is, the present invention provides (A) polyethylene, polypropylene, ethylene copolymer, propylene copolymer or
93 to 40% by weight of at least one synthetic resin selected from EVA resins, (B) 5 to 40% by weight of fine particle silicic acid or silicate having a specific surface area of 100 to 400 m ² /g, (C) a polyethylene Oxide compound b polypropylene oxide compound and c carboxylate, sulfate ester salt, sulfonate, phosphate ester salt, ammonium salt,
or 2 to 20% by weight of at least one compound selected from the group consisting of organic electrolytes having the structure of at least one salt selected from amine salts, and the weight ratio of the above components (C) and (B) (C) The antistatic resin composition is characterized in that /(B) is 2/3 or less and the volume resistivity value is 10 ¹¹ Ωcm or less. The feature of the present invention is that the volume resistivity value can be improved by combining components (B) and (C), which cannot obtain satisfactory volume conductivity even if they are blended individually, into the synthetic resin.
It is possible to obtain conductivity of 10 ¹¹ Ωcm or less. Moreover, since the color tones of component (B) and component (C) are colorless to light, the resulting composition has a color tone that can be colored. The present invention has a feature that is completely different from methods of adding conductive fillers such as carbon black and metal powder in that it does not significantly impair the color tone, and it also has various previously proposed methods in that it imparts volumetric conductivity. This method is clearly distinguished from the method of imparting surface conductivity by coating or kneading an antistatic agent. The present invention will be explained in detail below. The synthetic resin used in the present invention is not particularly limited, but thermoplastic synthetic resins are preferably used,
Examples include polyethylene, ethylene copolymers,
Examples include EVA resin, polypropylene, propylene copolymer, polystyrene, ABS resin, AS resin, methacrylic resin, polyamide, polycarbonate, polyester resin, and vinyl chloride resin. Among them, polyolefin resins such as polyethylene, polypropylene, ethylene copolymers, propylene copolymers, and
EVA resin is particularly useful as a raw material resin for the compositions of the present invention. The fine particle silicic acid or silicate used in the present invention may be produced by any method such as a dry method or a wet method, but it is necessary that the specific surface area thereof is 100 to 400 m ² /g. If the specific surface area is less than 100 m ² /g or more than 400 m ² /g, satisfactory volumetric conductivity cannot be obtained. Examples of polyethylene oxide compounds and polypropylene oxide compounds used in the present invention include polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene block copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene Examples of organic electrolytes with a salt structure include carboxylic acid salts such as potassium acetate and sodium laurate, sulfuric acids such as sodium alkyl sulfate, and sodium polyoxyethylene alkyl ether sulfate. Sulfonates such as ester salts, sodium alkyl sulfonates, sodium alkylbenzenesulfonates, sodium alkylnaphthalene sulfonates, sodium dialkyl sulfosuccinates, sodium alkyl phosphates,
Examples include phosphate ester salts such as sodium polyoxyethylene alkyl ether phosphate, tertiary amine salts, and amine salts such as quaternary ammonium salts. Moreover, these compounds can be used in combination as necessary. The blending ratio of component (B) in the present invention is 5 to 40% by weight.
The blending ratio of component (C) is 2 to 20% by weight.
Further, the blending ratio of component (C) and component (B) is preferably (C)/(B)≦2/3. If component (B) is less than 5% by weight, satisfactory volumetric conductivity cannot be obtained, and
If it exceeds 40% by weight, the mechanical properties will be greatly reduced during processing of the composition, causing various problems. Furthermore, if the blending ratio of component (C) and component (B) is (C)/(B)>2/3, component (C) tends to precipitate onto the surface of the composition, which is not preferable. Any suitable mixing or kneading method can be used to blend component (B) and component (C) into the synthetic resin, such as a Henschel mixer, kneader, extruder, Banbury mixer, roll, etc. I can give you a method. Methods for adding and blending component (C) include adding it alone, adding it as a solution, and adding it as component (B).
There are methods such as attaching it in advance and adding it, but the ingredients
(A), (B), and (C) can be appropriately selected depending on the properties of each component. The composition of the present invention may contain various additives such as antioxidants, ultraviolet absorbers, colorants, etc., if necessary. Various molding methods such as extrusion molding, injection molding, and press molding can be applied to the composition of the present invention. The present invention will be explained below with reference to Examples, but these are merely illustrative and the present invention is not limited thereto. The volume resistivity value in the example was measured at 23℃50%RH using a super insulation meter (Toa Denpa Kogyo SM10-E).
Measured under atmosphere. Examples 1 to 3 Comparative Examples 1 to 5 EVA resin (MI 3 g/10 min, VA content 15% by weight) was mixed with fine particles of silicic acid and polyethylene glycol (molecular weight 200) with different specific surface areas at a predetermined blending rate in a small kneader. The mixture was kneaded and blended at a resin temperature of 160°C to create a press sheet with a thickness of 0.2 mm. Table 1 shows the physical properties of the obtained press sheet.

[Table] The press sheets obtained in Examples 1 to 3 are as follows:
It had a volume resistivity value of 10 ¹¹ Ωcm or less, and was colorless and transparent. Examples 4 to 10 80% by weight of EVA resin (MI 3 g/10 min, VA content 15% by weight), 15% by weight of particulate silicic acid with a specific surface area of 240 m ² /g and 5% by weight of various compounds as component (C). The resin was kneaded and blended in a small kneader at a resin temperature of 160°C to create a press sheet with a thickness of 0.2 mm. Table 2 shows the physical properties of the obtained press sheet.

[Table] The press sheets obtained in Examples 4 to 10 are
It had a volume resistivity value of 10 ¹¹ Ωcm or less, and was colorless and transparent. Example 11 80% by weight of EVA resin (MI 3 g/10 min, VA content 15% by weight), 15% by weight of microparticle silicic acid with a specific surface area of 240 m ² /g and 4.5% by weight of polyethylene glycol (molecular weight 400), 0.5% by weight of potassium acetate. (Here, potassium acetate was made into a 65% by weight aqueous solution and mixed with polyethylene glycol.) was kneaded and blended in a small kneader at a resin temperature of 160°C to a thickness of 0.2% by weight.
A press sheet of mm was created. The obtained pressed sheet has a volume resistivity value of 8×10 ⁸ Ωcm or less,
It was colorless and transparent. Example 12 65% by weight of EVA resin (MI 3 g/10 min, VA content 15% by weight), 30% by weight of finely divided silicic acid with a specific surface area of 200 m ² /g and 5% by weight of trimethylhydroxyethylammonium chloride (where trimethylhydroxyethylammonium chloride Ethyl ammonium chloride was made into an aqueous solution, mixed with particulate silicic acid, and dried.)
are kneaded and blended in a small kneader at a resin temperature of 160℃,
A pressed sheet with a thickness of 0.2 mm was created. The obtained press sheet had a volume resistivity value of 8×10 ⁸ Ωcm or less, and was colorless and transparent. Example 13 Low density polyethylene (MI 1.5g/10min, density
0.922g/cm ² ), 15% by weight of fine particles of silicic acid with a specific surface area of 240m ² /g and 5% by weight of sodium dodecylbenzenesulfonate were kneaded and blended in a small kneader at a resin temperature of 160°C, and the thickness was 0.2mm. A press sheet was created. The obtained press sheet is 8×
It had a volume resistivity value of 10 ⁸ Ωcm or less, and was colorless and transparent. Example 14 Oxidation of 73% by weight of polypropylene (MI 6 g/10 min, random copolymer with 4% ethylene content) with 20% by weight of finely divided silicic acid with a specific surface area of 200 m ² /g and 7% by weight of polyethylene glycol (molecular weight 200) After mixing with an inhibitor using a Henschel mixer, the mixture was kneaded and granulated using a twin-screw extruder at a resin temperature of 220°C. The obtained pellets were made into a pressed sheet with a thickness of 0.2 mm. The obtained press sheet is 2×
It had a volume resistivity of 10 ⁹ Ωcm, and was colorless and transparent. Example 15 A press sheet obtained by replacing polyethylene glycol with sodium dodecylbenzenesulfonate in Example 14 had a volume resistivity value of 8×10 ⁸ Ωcm or less, and was colorless and transparent. Example 16 Using the pellets obtained in Example 14, a molded product with a thickness of 1.5 mm was obtained by injection molding (set temperature: 200°C). The obtained molded article had a volume resistivity value of 4×10 ⁹ Ωcm, and was colorless and transparent. Example 17 80% by weight of EVA resin (MI 3g/10 min, VA content 15% by weight), 15% by weight of fine particle silicic acid with a specific surface area of 240 m ² /g and 5% by weight of polyethylene glycol (molecular weight 200) were added to a Banbury mixer. After kneading and blending the resin into pellets at a resin temperature of 150°C, the pellets were formed into a pellet by inflation molding (set temperature: 160°C) to a thickness of 0.1
A film of mm was obtained. The obtained film was 5×
It had a volume resistivity value of 10 ⁹ Ωcm, and was colorless and transparent.

Claims (1)

[Scope of Claims] 1 (A) 93 to 40% by weight of at least one synthetic resin selected from polyethylene, polypropylene, ethylene copolymer, propylene copolymer, or EVA resin, (B) 100 to 400 m ² /g. 5 to 40% by weight of particulate silicic acid or silicate having a specific surface area, (C) a polyethylene oxide compound b polypropylene oxide compound and c carboxylate, sulfate ester salt, sulfonate, phosphate ester salt, ammonium salt,
or 2 to 20% by weight of at least one compound selected from the group consisting of organic electrolytes having the structure of at least one salt selected from amine salts, and the weight ratio of components (C) and (B) above (C )/(B) is 2/3 or less, and has a volume resistivity value of 10 ¹¹ Ωcm or less.