JPS61206641A - Conductive sheet or film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to electrically conductive sheets or films, particularly electrically conductive sheets or films.

It relates to a conductive sheet or film with excellent colorability and durability.

(Prior technology) Semiconductor wafer storage containers, electronic and electrical components, and wall and flooring materials for semiconductor manufacturing plants and bio-clean rooms are required to have antistatic functions to prevent dust from adhering to the air. There are many cases where

Japanese Utility Model Application Publication No. 58-48435 discloses a conductive decorative plate for antistatic purposes. This conductive decorative board consists of processed paper as a base material layer and a resin layer as a surface material, and carbon fiber is mixed into the processed paper. Since the black color of the carbon fibers can be seen through the resin layer, the resulting conductive decorative board has a black color as a whole. However, since the conductive decorative board to be used as wall material or floor material is black in this way.

The places where it can be applied must be extremely limited, and it is not practical. Therefore, in order to hide this black color, the resin layer is made thicker or a printing layer containing a pigment is formed on the five base material layers. However, this method has a problem in that the conductivity of the decorative board decreases.

(Problems to be Solved by the Invention) The present invention is intended to solve the above-mentioned conventional drawbacks, and its purpose is to provide a sheet or film with excellent conductivity and colorability.

(Means and effects for solving the problems) The conductive sheet or film of the present invention includes conductive powder and/or conductive whiskers and pigments on the surface of a woven or nonwoven fabric for a base material containing conductive fibers. The above object is achieved by providing a printed layer containing the following: and providing a thermosetting or thermoplastic resin film layer on the surface of the printed layer.

The conductive woven fabric or nonwoven fabric for a base material (hereinafter referred to as base material) of the present invention is composed of non-conductive fibers and conductive fibers. Non-conductive fibers used for this woven or non-woven fabric include glass fiber and rock wool.

There are cellulose fibers, 2 synthetic polymer fibers, etc. Examples of conductive fibers include carbon fiber; stainless steel;
Metal fibers such as aluminum; glass fibers coated with metals such as aluminum, zinc, and nickel are used. The length of these conductive fibers is preferably 311 mm or more. If it is too small, sufficient conductivity cannot be obtained. The thickness of the fibers is preferably thin in order to obtain sufficient conductivity with a small amount. A suitable thickness is 50 μm or less. The conductive fibers are mixed in an amount of 3 to 4% by weight or more based on the entire base material. Below this value, sufficient volume resistivity (103 to 108 Ω・c
m) cannot be obtained. If the amount of conductive fibers is excessive, it will not be possible to finish the fabric into a woven or nonwoven fabric. This conductive woven fabric or nonwoven fabric can be obtained by mixing conductive fibers with non-conductive fibers and using a weaving machine, a knitting machine, paper making, or the like.

A printing layer is formed on the surface of the base material thus obtained. The printing ink used to form the printing layer is
Contains pigment, resin, conductive powder and/or conductive whiskers, and solvent.

As the pigment, any known pigment such as titanium oxide or zinc white can be used as appropriate. As the resin, urethane resin, vinyl chloride resin, etc. are preferably used.

The conductive powder is preferably a conductive powder obtained by adding a doping agent of a trivalent or pentavalent metal to a metal oxide. Examples include tin oxide doped with antimony and zinc oxide doped with aluminum. Examples of conductive whiskers include conductive fibrous single crystals made of potassium titanate or alumina. These conductive powders and/or conductive whiskers are contained in the printing ink (solid content) from 1 to 5
It is contained in a proportion of 0% by weight, preferably 1 to 25% by weight. If the amount is too small, good conductivity cannot be obtained. Even if an excessive amount is used, the conductivity does not improve significantly.

This will only increase costs. As a solvent, toluene,
Common organic solvents such as xylene are used.

The pigment, resin, conductive powder and/or conductive whisker are mixed with this solvent to form a printing ink having an appropriate viscosity.

The printing layer formed by applying the printing ink effectively hides the color of the substrate due to the pigment contained therein. At the same time, it exhibits good electrical conductivity due to the electrically conductive powder and/or electrically conductive whiskers contained therein. These conductive powders and conductive whiskers have a white appearance and become transparent when contained in printing ink, so that they do not affect the color of pigments contained therein at the same time. Therefore, a printed layer of a desired color derived from the pigment can be obtained.

In order to protect the surface of the printed layer thus formed, a film layer is further formed on the surface of the printed layer. The coating layer is formed by coating the printing surface with a thermosetting resin or thermoplastic resin, if necessary.

It is formed through post-processing such as heat curing and compression.

Thermosetting resins forming the film layer include polyester, diallyl phthalate, polyurethane, melamine, and phenolic resin. Thermoplastic resins include PVC, acrylic, ethylene-vinyl acetate copolymer, butyral resin, natural rubber, synthetic rubber, and the like. These are dissolved in a solvent or heated when used.

For the coating layer, as necessary to increase the conductivity of the final sheet or film.

Contains conductive powder and/or conductive whiskers. As the conductive powder and conductive whiskers, those contained in the printing layer and described above are used. These conductive powders and/or conductive whiskers account for 50% by weight or less of the total resin used.

It is preferably contained in a proportion of 1 to 25% by weight. If it exceeds 50% by weight, the surface strength will decrease. When a large amount of conductive powder or conductive whiskers is contained in the printed layer, sufficient conductivity can be obtained even if the coating layer does not contain conductive powder or conductive whiskers. The amount of conductive powder and conductive whiskers in the coating layer is determined as appropriate depending on the conductivity of the printed layer and the thickness of the coating layer. Since conductive whiskers are in the form of fibers, when conductive whiskers are mixed in the coating layer, they are likely to be electrically conductive with the conductive powder and conductive whiskers in the printed layer. The conductivity is improved compared to when both are present. Therefore, the film layer can exhibit sufficient electrical conductivity even if it contains only a small amount of electrically conductive whiskers.

The sheet or film of the present invention exhibits good electrical conductivity as a whole because at least both the base material and the printed layer have electrical conductivity. Its surface specific resistance value is 2
Usually, it is 102 to 10 BΩ.

The color of the substrate containing metal fibers or carbon fibers (usually black to gray) is effectively hidden by the printed layer, so the coating layer provided on the printed layer can ensure the durability of the sheet or film. It is sufficient if the thickness is as small as possible. Due to the presence of a film layer.

The sheet or film has excellent scratch resistance and water resistance. Therefore, it does not become a source of dust unlike conductive woven fabrics or nonwoven fabrics that do not have a film layer on their surface. This sheet or film also.

For example, it can be used for walls and floors in clean rooms, and electromagnetic shielding, which require an antistatic effect.

(Example) The present invention will be explained below using examples.

A printing ink having the following composition was gravure coated on a conductive nonwoven fabric for base material (weighing 55 g/rrf) consisting of 8 wt. I worked on it.

Aluminum doped zinc oxide 11% by weight Urethane resin 3% by weight Titanium oxide 58% by weight Toluene 28% by weight Polyester resin is applied to the surface of the white printed layer formed.
It was applied at a rate of 0 g/rd. This polyester resin contains 10% by weight of zinc oxide doped with aluminum as a conductive powder. The paper obtained was white and had a surface resistivity of 1.8×10 6 Ω.

Comparison 1: Same as Example 1 except that no flame printing ink was applied. The surface resistivity of the obtained paper was 2.0×10 5 Ω, indicating good conductivity, but its appearance was gray.

Comparative Example 2 Same as Example except that the printing ink does not contain conductive powder. The paper obtained was white in color and had a surface resistivity of 3.0×10”Ω.

(Effects of the Invention) As described above, the conductive sheet or film of the present invention can be colored in any color depending on the pigment of the printed layer because the base layer is effectively hidden by the printed layer having conductivity. Shiroru. Since the color of the base material is hidden, there is no need to make the film layer thicker to hide the base material layer. Because of the coating layer, this sheet or film has excellent durability. By selecting an appropriate resin for this coating layer, a sheet or film with excellent chemical resistance can be obtained. Such sheets or films are used as wall and floor materials in clean rooms.

It can be used in many ways, including electromagnetic shielding.

that's all

Claims (1)

[Claims] 1. A printed layer containing conductive powder and/or conductive whiskers is provided on the surface of a woven or nonwoven fabric for a substrate containing conductive fibers, and the surface of the printed layer is thermoset. A conductive sheet or film with a film layer of thermoplastic or thermoplastic resin. 2. The conductive sheet or film according to claim 1, wherein the conductive fibers are carbon fibers, metal fibers, or glass fibers coated with a conductive material. 3. The conductive sheet or film according to claim 1, wherein the printed layer contains the conductive powder and/or conductive whiskers in a proportion of 1 to 50% by weight. 4. The conductive sheet or film according to claim 1, wherein the film layer contains conductive powder and/or conductive whiskers in a proportion of 50% by weight or less. 5. The conductive sheet or film according to claim 1 or 3, wherein the conductive powder is a conductive powder obtained by adding a doping agent to a metal oxide.