JPH055094A - Electrostatic material - Google Patents

Abstract

PURPOSE:To provide an electrostatic material comprising a specific urethane rubber or resin as a substrate and a specific amount of a metal salt contained in the substrate, having a good electrostatic property or static electricity- removing property, and further having an excellent wear resistance. CONSTITUTION:The objective electrostatic material comprises (A) a substrate comprising an urethane rubber or resin which is prepared from an organic compound having (i) isocyanate groups and hydroxyl groups or (ii) isocyanate groups, hydroxyl groups and amino groups as a raw material and which has urethane bonds in the molecule or has urea bonds, biuret bonds and/or allophanate bonds as well as the urethane bonds in the molecule and (B) a metal salt such as an alkali (alkaline earth) metal salt contained in the substrate in an ionic state in an amount of 1.0X10<-6> to 1.0 X10<-2>mol per g of the component A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic material made of an organic polymer material having an antistatic ability, and more specifically,
The present invention relates to an antistatic material that uses urethane rubber or urethane resin as a base material and exhibits an electrostatic charge prevention or static charge removal effect by ion conduction.

[0002]

2. Description of the Related Art Antistatic materials are used for manufacturing or assembling electronic parts such as semiconductor devices, computer rooms, electronically controlled automatic manufacturing lines, manufacturing or processing processes for handling powders and resin films, flammable gases and flammable materials. It is used in a wide variety of fields such as manufacturing or processing processes of chemicals and explosive chemicals, and equipment used. The factors of the characteristics that the antistatic material must satisfy are the electrical resistivity and the half-life of the charged voltage. Electric resistance (surface resistivity, volume resistivity) Mitsubishi Petrochemical Co., Ltd. resistivity meter (Hirester IP) and HRS (outer diameter 18 mmφ) as electrodes were used for the respective measurement methods. 10 V or 500 V, application time 1 minute, measurement atmosphere at room temperature 20 ° C., relative humidity 60%, half-life time of voltage charge, static static nest meter manufactured by Shishido Electrostatic Co., Ltd., applied voltage 10 kV, distance between sample and electrode 20
mm, when the measurement atmosphere is the same as the electrical resistivity, the electrical resistivity of the antistatic material is a surface resistivity of 10 ⁵ to 10 ¹²
(Ω / □), volume resistivity of 10 ⁴ to 10 ¹¹ (Ω · c
m), the half-life of charged voltage is 1 second or less. As conventional anti-static materials that meet these conditions, rubber or resin mixed with carbon black or metal powder, or an antistatic agent (surfactant), or a conductive coating on the surface of an insulator such as rubber or resin Some have been given.

[0003]

However, among the above-mentioned conventional antistatic materials, the one in which carbon black or metal powder is kneaded into rubber or resin is very small in the filling amount of the carbon black or metal powder. Change causes a large change in the electrical resistivity of the antistatic material, making it difficult to produce a material exhibiting stable antistatic properties. Furthermore, due to surface abrasion, carbon black or metal powder on the surface is difficult to produce. However, there is a problem in that it causes pollution, and that the electrical resistivity increases and the antistatic ability decreases. In addition, for antistatic materials made by kneading an antistatic agent in rubber or resin, the antistatic ability is significantly reduced in the low humidity atmosphere where static electricity is most likely to occur.
There is a drawback that the anti-static ability is severely deteriorated due to wear or the like. Further, even an antistatic material having a conductive coating on its surface has a drawback that its antistatic ability is lost due to abrasion of the surface conductive layer. The present invention has been made to solve the above problems, in production, stable antistatic characteristics can be easily obtained, and in addition, the characteristics are excellent in stability against changes in atmosphere such as temperature and humidity. In particular, it is an object of the present invention to provide an antistatic material having excellent wear resistance, which does not lose antistatic ability even in a low humidity atmosphere, and does not lose antistatic ability due to general cleaning (water, alcohol, etc.) and surface abrasion. To do.

[0004]

Means for Solving the Problems The present invention uses an organic substance containing an isocyanate group and a hydroxyl group, or an isocyanate group, a hydroxyl group and an amino group as a raw material, has a urethane bond in the molecular structure, or together with a urethane bond, A part selected from the group consisting of urea bond (urea bond), buret bond and allophanate bond,
Alternatively, a urethane rubber or urethane resin having all of them is used as a base material, and a metal salt is contained in the base material in an ionic state, and the concentration of the contained metal salt is 1.0 with respect to the urethane rubber or urethane resin 1 (g). ^{X10 -6} to 1.0 x
It is in the range of 10 ⁻² (mol / g) and has an antistatic ability by ion conduction.

As a base material of the antistatic material according to the present invention, urethane rubber or urethane resin which has elasticity in use, is excellent in mechanical strength, is easy to obtain a transparent material, and can dissolve a metal salt in an ionic state. Is used. NBR, PV
C, various nylons, cellulose acetate, ethylene vinyl alcohol copolymer, etc. also dissolve the metal salt in the ionic state,
Although it is possible to exhibit antistatic properties, urethane is selected in the present invention because it is easier to dissolve salt in an ionic state than the other materials. The urethane rubber or resin is classified into thermosetting cast urethane, millable urethane, and thermoplastic urethane resin.

As a raw material for cast urethane, diisocyanate and polyol, and short-chain polyol or diamine as a curing agent are used. The isocyanate group in the diisocyanate is a urethane bond with the hydroxyl group in the polyol, and is an urea bond with the amino group in the diamine.
Under special conditions, it forms an allophanate bond with the urethane group thus produced and a buret bond with the urea group. Specifically, as the diisocyanate,
TDI (tolylene diisocyanate), MDI (diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate), TODI (tolidine diisocyanate), NDI (naphthalene diisocyanate),
PPDI (paraphenylene diisocyanate), HDI
(Hexamethylene diisocyanate), IPDI (isophorone diisocyanate), CHDI (cyclohexyl diisocyanate), XDI (xylylene diisocyanate), H ₆ XDI (1,3-bis (isocyanatomethyl) cyclohexane), H ₁₂ MDI (dicyclohexylmethane diisocyanate) , TMXDI (tetramethylxylylene diisocyanate), DDI (dimer acid diisocyanate), LDI (lysine diisocyanate) and the like. Further, regarding the polyol,
As the polyether-based polyol, for example, polyoxypropylene polyol (PPG), polyoxypropyleneoxyethylene polyol (PO / EO copolymer),
Polytetramethylene ether glycol (PTMG),
Examples of the tetrahydrofuran-alkylene oxide copolymerized polyol, and polyester-based polyols include condensed polyester polyols, polycaprolactone polyols (PCL), and polycarbonate diols, and other polyols include polybutadiene polyols polyolefin polyols, acrylic polyols, and the like. Be done. Further, as the diamine used as the curing agent, 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA) can be mentioned as a representative example.

As the raw material of the millable urethane, diisocyanate, organic peroxide or sulfur is used as a crosslinking agent in addition to the raw material of the cast urethane.

The thermoplastic urethane resin is basically the same as in the case of the thermosetting type, and is obtained by the addition polymerization reaction of diisocyanate and polyol.

The antistatic material according to the present invention is obtained by dissolving a metal salt in an appropriate solvent and then adding it to a raw material of the urethane rubber or resin as a base material or a crosslinked urethane rubber. Examples of the metal salts include alkali metal halides and alkaline earth metal salts, alkali metal nitrates, alkali metal thiocyanates and alkaline earth metal salts, alkali metal perchlorates and alkaline earth metal salts, and the like. As an example of the solvent, water,
Examples thereof include toluene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone, chloroform, acetone and dimethylformamide.

In order for the present invention to have excellent properties as an antistatic material, it is important to select a urethane rubber and a resin that can contain a metal salt in an ionic state.
It is important that the concentration of the contained metal salt is within a range showing an electric resistivity suitable as an antistatic material. The metal salt has a surface resistivity of 10 ⁵ to 10 ¹² (Ω / □) and a volume resistivity of 10 ⁴ to.
It is necessary to have a concentration above a certain level satisfying the condition of 10 ¹¹ (Ω · cm), but if added in excess, it will affect the physical properties of the antistatic material body. The present inventors have set the concentration of the contained metal salt to 1.0 × 10 ⁻⁶ to 1.0 × 10 ⁻² (mol / g).
It has been found that an antistatic material having stable physical properties and having good physical properties can be obtained by adjusting the content within the range.

[0011]

According to the present invention, the urethane rubber or resin contains a metal salt in an ionic state to prevent static electricity from being charged by ion conduction or to remove static electricity.

[0012]

EXAMPLES Examples of the present invention will be described below.
It is not limited by this.

Alkali metal salt potassium thiocyanate was dissolved in acetone and added to Takenate L-2705 (manufactured by Takeda Pharmaceutical Co., Ltd.), which is a raw material for cast urethane rubber, and the mixture was uniformly mixed, and then acetone was volatilized. Then, the rubber was crosslinked by adding MOCA (3,3′-dichloro-4,4′-diaminodiphenylmethane). Inside the rubber, potassium thiocyanate was in an ionic state, that is, thiocyanate ion and It is contained as potassium ion. The content concentration of potassium thiocyanate is 9.0 × 10 ⁻⁵ (mol / g).

FIG. 1 shows the relationship between the concentration and the electrical resistivity (surface resistivity, volume resistivity) when the concentration of potassium thiocyanate contained in the antistatic material of this example is changed. As described above, when the potassium thiocyanate concentration is 0.0 to 2.0 × 10 ⁻⁶ (mol / g), the electrical resistivity sharply decreases and becomes 2.0 × 10 ⁻⁶ (mol / g) or more. The concentration gradually decreases, but the concentration is 1.0
When it exceeds x 10 ⁻² (mol / g), problems such as a decrease in strength of the antistatic material body, white turbidity, and discoloration occur. Therefore, the surface resistivity of the antistatic material is 10 ⁵ to 10 ^5.
12 (Ω / □), volume resistivity of 10 ⁴ to 10 ¹¹ (Ω ·
cm), and the concentration condition of the metal salt to have good physical properties is 1.0 × 10 ⁻⁶ as described above.
It is in the range of ^{1.0 × 10 -2 (mol / g} ) from, but if potassium thiocyanate in this embodiment, and more considering the stability and physical properties of resistivity, 4.0 × 10
It is preferably in the range of ⁻⁶ to 1.0 × 10 ⁻⁴ (mol / g).

Here, the antistatic property of this embodiment will be described in comparison with a conventional product.

The relationship between humidity and temperature changes and surface resistivity in this example is shown in FIG. 2, the relationship between humidity and temperature changes and charged voltage half-life is shown in FIG. 3, and the conventional polyolefin resin is charged. FIG. 4 shows the relationship between humidity and temperature changes and surface resistivity in an antistatic material prepared by kneading an inhibitor, and FIG. 5 shows the relationship between humidity and temperature changes and charged voltage half-life. When the temperature atmosphere is changed to 20, 30, 40 ° C. and the relative humidity atmosphere is changed to 40, 60, 80%, both of the present example and the conventional product have a tendency that the resistivity decreases as the temperature rises, Although a slight improvement in antistatic property is observed, there is a clear difference in the antistatic property between the two depending on the change in the humidity atmosphere. Especially, the conventional product has a large electrification voltage half-life at a humidity of 60% or less. In contrast, the antistatic ability is remarkably lowered, whereas the present example shows an extremely low value with little involvement in the humidity change.

Further, in the present example, the conventional antistatic material using the above antistatic agent and the antistatic material prepared by applying a conductive coating to the surface of soft vinyl chloride, the number of times of polishing when the surface was sanded-the surface The relationship of resistivity
These are shown in FIGS. 6, 7, and 8, respectively. Place each of the sheet-shaped samples on a # 800 sandpaper attached to a flat plate.
It was evaluated by pressing the sample with 0 (gf / cm ² ) pressure and sliding the sample as it was for 20 cm to give a polishing count of 1. In contrast to the two conventional products, the surface resistivity increases as the polishing count increases. It is recognized that in this example, even if the surface is polished, the resistivity does not change, and that it exhibits stable antistatic properties against abrasion.

The electrical resistivity and half-life of electrified voltage shown in this example are measured by the electrical resistivity (surface resistivity, volume resistivity) Mitsubishi Yuka Co., Ltd. resistivity measuring instrument ( Highester IP) and HRS (outer diameter 18 mmφ) are used as electrodes. Applied voltage is 10 V or 500 V, applied time is 1 minute, measurement atmosphere is room temperature of 20 ° C., relative humidity is 60%, half-voltage of electrified voltage Shishido Electrostatic Co., Ltd. Using a static Honest meter made by, applied voltage 10kV, distance between sample and electrode 20
mm, measurement atmosphere is data when the electrical resistivity is the same.

[0019]

INDUSTRIAL APPLICABILITY As described above, the antistatic material according to the present invention can obtain good antistatic properties without difficulty in production by adjusting the content concentration of the metal salt within the appropriate range. Be done. (B) It exhibits stable characteristics against changes in atmosphere such as temperature and humidity, and exhibits excellent anti-static ability that has never been seen even in low humidity atmosphere. (C) Stable characteristics against wear of the surface due to cleaning and polishing. And so on.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the concentration and the electrical resistivity (surface resistivity, volume resistivity) when the concentration of potassium thiocyanate contained in the examples of the antistatic material according to the present invention is changed. ..

FIG. 2 is a graph showing the relationship between humidity and temperature changes and surface resistivity in this example.

FIG. 3 is a graph showing a relationship between humidity and temperature changes and charged voltage half-life in the present example.

FIG. 4 is a graph showing a relationship between humidity and temperature change and surface resistivity in a conventional antistatic material prepared by kneading an antistatic agent in a polyolefin resin.

FIG. 5 is a graph showing a relationship between humidity and temperature change-charge voltage half-life in an antistatic material using the antistatic agent.

FIG. 6 is a graph showing the relationship between the number of times of polishing and the surface resistivity when polishing the surface with sandpaper in the present example.

FIG. 7 is a graph showing the relationship between the number of times of polishing and the surface resistivity when the surface of the antistatic material using the antistatic agent is polished with sandpaper.

FIG. 8 is a graph showing the relationship between the number of times of polishing and the surface resistivity when the surface of a conventional antistatic material prepared by applying a conductive coating to a soft vinyl chloride surface is polished with sandpaper.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yutaka Matsuzawa, Yutaka Matsuzawa, 3-105, Sugaya, Ageo City, Saitama Prefecture Fukoku Co., Ltd. (72) Hiroshi Kuramochi, 5-18, Higashikawaguchi, Kawaguchi City, Saitama Prefecture

Claims (1)

Claims: 1. An organic substance containing an isocyanate group and a hydroxyl group, or an isocyanate group, a hydroxyl group and an amino group is used as a raw material and has a urethane bond in its molecular structure, or a urethane bond together with a urethane bond. (Urea bond), a urethane rubber or a urethane resin having a part or all selected from the group consisting of a buret bond and an allophanate bond is used as a base material, and a metal salt is contained in an ionic state inside the base material, and the content thereof is contained. The concentration of the metal salt is 1.0 × 10 ⁻⁶ to 1.0 × 10 ⁻² (mol / g) with respect to urethane rubber or urethane resin 1 (g).
An antistatic material having an antistatic ability by ionic conduction, characterized in that 2. The contained metal salt is an alkali metal salt or an alkaline earth metal salt, has good solubility in urethane rubber or urethane resin, and the concentration of the contained metal salt is 1 g of urethane rubber or urethane resin. On the other hand, 4.0x
The antistatic material according to claim 1, which is in the range of 10 ⁻⁶ to 1.0 × 10 ⁻⁴ (mol / g).