JPH03122165A - Electroconductive resin composition - Google Patents

Abstract

PURPOSE:To provide a resin composition having moisture dependency-reduced electroconductivity without deteriorating the original color of a resin by compounding the resin with specific amounts of an alkali metal salt and a polyether polymer. CONSTITUTION:(A) A resin selected from a polyurethane resin, an epoxy resin, ethylene-vinyl acetate copolymer, an acrylic resin and a polyester resin is compounded with (B) 0.01-20 wt.% of an alkali metal salt, preferably the metal salt of an anion selected from tetrafluoroborate, perchlorate, trifluoroacetate, thiocyanate and iodide and (C) 0.5-60 wt.% of a polyether polymer, preferably a block copolymer comprising polyethylene oxide and polypropylene oxide or a crosslinked product thereof having 10-90% of the polyethylene oxide chain.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a conductive resin composition having an antistatic effect.

(Conventional technology) In recent years, with the advancement of plastic molding technology, many of the various housings and packaging materials have become made of plastic, and plastic products have also entered the field of engineering parts such as gears. ).

It is well known that the plastics used in these applications are insulators unless specially treated and have a tendency to collect static charges on their surfaces.

On the other hand, as the degree of integration of integrated circuits such as ICs and LSIs used in various electrical devices increases, failures due to static electricity are increasing. It is strongly desired to prevent static electricity when using electronic equipment.

In order to meet these demands, methods have been developed such as incorporating inorganic conductive fillers and organic surfactants into plasti and soku products, or coating them with binders.

Antistatic treatment using inorganic conductive fillers has excellent conductivity, but when used on transparent polymer materials,
This had the disadvantage of impairing its transparency.

In addition, various surfactants are on the market as organic antistatic treatments, but these antistatic treatments use moisture in the air to develop conductivity, so their effectiveness is greatly affected by humidity. It had some disadvantages. On the other hand, as an organic conductive composition, polyethylene oxide (
After dissolving a polymer having a polar group in its molecular structure, such as PEO (hereinafter referred to as PEO) or polypropylene oxide (hereinafter referred to as PPO), in an organic solvent, a thin film is formed by a casting method. A polymer-alkali metal salt complex obtained by immersing an alkali metal salt in a solution of a solvent and then drying is known [for example, Br, P
olymer J, + 1 +319 (19
75) ; Fast I on Tran
sferIn Ionlcs-5-, 685 (198
1) Ko. This complex has relatively high ionic conductivity at room temperature.

However, when performing antistatic treatment on plastics using a composite of PEO or PPO alone in which an alkali metal salt is dissolved, sufficient performance cannot be obtained because PEO alone is not compatible with resins other than polyurethane resins and epoxy resins. do not have. In addition, it has a high solubility in water, so even if it is mixed into plastic as an antistatic agent, it will dissolve in water and will be extracted with water, gradually reducing its antistatic effect. Also, PPO
When used alone, it has good compatibility with acrylic resins and polyester resins in addition to urethane resins and epoxy resins, but the solubility of alkali metal salts is low and only low conductivity can be obtained.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and its purpose is to provide a conductive resin composition with good antistatic properties, and An object of the present invention is to provide a conductive resin composition with low humidity dependence without impairing the original color tone of the resin.

(Means for Solving the Problems) As a result of intensive research, the present inventors have completed a conductive resin composition that can achieve the above object.

That is, the conductive material is characterized by containing an alkali metal salt and a polyether polymer in a resin selected from polyurethane resin, epoxy resin, ethylene-vinyl acetate copolymer resin, acrylic resin, or polyester resin. It is a resin composition.

The alkali metal salt used in the present invention is not particularly limited; , halogen acid anions such as chloric acid and bromate; perhalogen acid anions such as periodic acid, perchloric acid, and perbromate; organic acid anions having alkylbenzenesulfonic acid and alkylbenzenesulfonic acid; and thiocyanic acid. The ions are lithium, sodium, potassium,
Rubidium and cesium. From the viewpoint of ionic conductivity, lithium fluoroborate, lithium iodide, lithium perchlorate, lithium trifluoroacetate, potassium thiocyanate, and lithium thiocyanate are preferred.

The amount of alkali metal salt added to the resin is 0.01% by weight or more and 20% by weight or less, and adding 0.01% by weight without grooves will not provide a sufficient antistatic effect, and adding more than 20% by weight will not provide a sufficient antistatic effect. However, the conductivity will not be improved any further. In addition, the amount of polyether polymer added is 0.5% by weight or more, 6% by weight or more.
It is 0% by weight or less. If the amount of the polyether polymer added is less than 0.5% by weight, good conductivity will not be provided, and if it is more than 60% by weight, the physical properties such as strength of the resulting conductive resin composition will deteriorate.

The content of polyethylene oxide chains in the polyether polymer of the present invention is not particularly limited, but is 10%
It is preferably 90% or less. If it is less than 10%, the conductivity becomes unstable, so the amounts of the alkali metal salt and polyether polymer must be increased. Moreover, if it exceeds 90%, the compatibility with acrylic resins and polyester resins decreases, and the appearance of these polymeric materials tends to be impaired.

Further, as the polyether polymer of the present invention, a copolymer consisting of polyethylene oxide and polypropylene oxide, a derivative obtained by esterifying some or all of the terminal hydroxyl groups, and further a crosslinked polymer can be used.

Such crosslinked polymers include those obtained by converting some or all of the terminal hydroxyl groups of a copolymer of polyethylene oxide and polypropylene oxide into esters of acrylic acid or methacrylic acid and then polymerizing them, and those obtained by using polyisocyanate as a crosslinking agent. Examples include those made into crosslinked polymers by reacting with terminal hydroxyl groups.

The electrically conductive resin composition of polyurethane resin, epoxy resin, ethylene-vinyl acid copolymer resin/acrylic resin, and polyester resin of the present invention thus obtained is transparent, has excellent water resistance, and has good antistatic property. Due to its effectiveness, it can be used in various casing materials (film sheet). It can also be used for antistatic paints, electrostatic adhesives, low-frequency treatment equipment, probe electrodes for electrocardiogram measurements, and the like.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Example 1 Commercially available polypropylene oxide has a molecular weight of 2000,
The content of ethylene oxide chains in the copolymer molecule is 10
% of polyethylene oxide and polypropylene oxide (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Epan 710) was used.

5 parts by weight of this polymer was heated to 90°C and 0.1 part by weight of lithium perchlorate (anhydrous) was added to obtain a milky white waxy composition consisting of lithium perchlorate and the block copolymer. .

This composition was added to 99.49 parts of thermoplastic polyurethane resin (Pandex, manufactured by Dainippon Ink Chemical Industries, Ltd.) at 0.00 parts.
After adding 51 parts and mixing, it was molded into a sheet and its surface resistivity was measured. The measurement results are shown in Table 1. Note that the surface resistance value of the thermoplastic polyurethane resin alone is also shown as a reference value.

Examples 2 to 5 Example 1 except that the contents of the block copolymer and lithium perchlorate in Example 1 were changed to the compositions shown in Table 1.
A polyurethane sheet having electrical conductivity was obtained according to the method. Table 1 shows the measurement results of the surface resistivity of this sheet.

Examples 6-7 The content of ethylene oxide chains in the copolymer molecule is 50
% (Example 6) and 90% (Example 7), a conductive polyurethane sheet was obtained according to Example 3. Table 1 shows the measurement results of the surface resistivity of this sheet.

Comparative Examples 1-2 The amount of lithium perchlorate added was 0.005% (Comparative Example 1)
, and 30% (Comparative Example 2). Table 1 shows the results of measuring the surface resistance of the resin obtained.

When the amount of lithium perchlorate added is 0.005%, the surface resistivity does not decrease much and no antistatic effect can be expected.

Therefore, no effect can be expected from the polyether block copolymer alone, and the presence of an alkali metal salt of 0.01% or more is required.

Furthermore, when the amount of lithium perchlorate added (2) is 30%, there is almost no difference from when it is 20%.

Examples 8 to 11 Instead of thermoplastic polyurethane resin, ethylene-vinyl acetate copolymer resin (Solex, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.) (Example 8), acrylic resin (manufactured by Sumitomo Chemical Co., Ltd., Sumipex) ) (Example 9), polyester resin (manufactured by Toshiku Co., Ltd., Chemit) (Example 10), epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat) (Example 11)
) was used in the same manner as in Example 3. Table 2 shows the measurement results of the surface resistivity of the obtained conductive resin composition.

The surface resistivity of each resin alone is 1014Ω.
/ It was more than a mouthful.

Example 12 Commercially available polypropylene oxide has a molecular weight of 2000,
The content of ethylene oxide chains in the copolymer molecule is 10
% of a block copolymer (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Epan 710), 10 parts of methyl methacrylate was added, and the two hydroxyl groups in the block copolymer molecule were converted by an ester conversion reaction. A polymer in which one of the polymers was a methacrylic ester was obtained.

100 parts by weight of this polymer was dissolved in toluene, and 0.01 part by weight of benzoyl peroxide was added for solution polymerization to obtain a crosslinked block copolymer of polyethylene oxide and polypropylene oxide.

The copolymer was heated to 90'C and 10% by weight of lithium perchlorate was added and mixed to obtain a transparent composition consisting of lithium perchlorate and crosslinked block copolymer.

5% by weight of the composition was added to a thermoplastic polyurethane resin (Pandex, manufactured by Dainichi Ink & Chemicals Co., Ltd.) and mixed, then molded into a sheet and its surface resistivity was measured. The results are shown in Table 3.

Example 13 As a crosslinked block copolymer, the molecular weight of polypropylene oxide was 1200. Polyisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate) is added to a copolymer with a polyethylene oxide chain content of 40%.
Example 12 was repeated except that a block copolymer crosslinked with urethane was used.

Table 3 shows the measurement results of the surface resistivity of the obtained polyurethane sheet.

Examples 14 to 18 The alkali metal salts to be added are lithium tetrafluoroborate (Example 14), lithium iodide (Example 15), lithium trifluoroacetate (Example 16), potassium thiocyanate (Example 17), or lithium thiocyanate. The procedure of Example 3 was followed except that (Example 18). Table 3 shows the measurement results of the surface resistivity of the obtained polyurethane sheet.

Table 4 Example 19 The surface resistivity of the conductive thermoplastic polyurethane resin sheet prepared in Example 3 was measured at 25° C., 13% RH, 160% RH, and 80% RH. The results are shown in Table 4.

Comparative Example 3 A resin composition prepared according to Example 3 except that the content of the copolymer was changed to 0% was molded into a sheet. 25℃, 3%RH160%RH and 8
Table 4 shows the measurement results of surface resistivity at 0% RH.

(Effects of the Invention) The conductive resin composition of the present invention can be produced without using any special mixing method, and exhibits excellent antistatic properties.

In addition, because it is transparent, it can be used in fields that require good transparency and colorability, such as brightly colored anti-static flooring materials and anti-fog plastic windows.

Furthermore, it has excellent water resistance and low humidity dependence, so its properties do not change over time and are highly reliable.

Claims (1)

[Scope of Claims] 1. A resin selected from polyurethane resin, epoxy resin, ethylene-vinyl acetate copolymer resin, acrylic resin, or polyester resin, containing 0.01% by weight or more and 20% by weight or less of an alkali metal salt, and 1. A conductive resin composition containing 0.5% by weight or more and 60% by weight or less of a polyether polymer. 2. The conductive resin composition according to claim 1, wherein the polyether polymer is a block copolymer of polyethylene oxide and polypropylene oxide, or a crosslinked polymer of the copolymer. 3. The conductive resin composition according to claim 1, wherein the anion of the alkali metal salt is one selected from tetrafluoroboron, perchloric acid, trifluoroacetic acid, thiocyanic acid, or iodine.