JPH0376667B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a soft antistatic film or sheet. [Prior art] In general, vinyl chloride films or sheets are very easily charged with electricity, and when used in clean room curtains, etc., they become charged and dust tends to adhere to them, and when IC products are packaged, the ICs are destroyed. There were many other problems. To solve the above problem, a conductive paint containing a conductive material mainly composed of carbon black, graphite, etc. on one side of an unplasticized vinyl chloride resin or a plasticized vinyl chloride resin film containing 10% or more of a low-molecular plasticizer. Antistatic vinyl chloride film coated with
47763) has been proposed. However, unplasticized vinyl chloride resin film is hard and cannot be used for clean room curtains, etc. as it cannot be used as a soft film. Because it contains a molecular plasticizer, sufficient antistatic effect cannot be obtained.In order to obtain sufficient antistatic effect, a large amount of carbon black, etc. must be added to the conductive paint, which causes the film to become completely black and red. However, there were drawbacks such as the inability to obtain colored films such as blue. [Object of the Invention] In view of the above-mentioned drawbacks, the present invention has been made with the object of providing an opaque, soft vinyl chloride resin film or sheet that has excellent antistatic effects and can be colored red, blue, etc. . [Structure of the Invention] The gist of the present invention is that an antistatic paint layer consisting of a resin binder, a liquid plasticizer, and a white or grayish-white conductive powder is laminated on at least one surface of a soft vinyl chloride resin film, and an opaque soft resin film is formed. Exists in antistatic film or sheet. The vinyl chloride resin film used in the present invention is a soft film made of vinyl chloride resin and a plasticizer. The above-mentioned vinyl chloride resin is a homopolymer of vinyl chloride and a copolymer of a monomer copolymerizable with vinyl chloride monomer, and examples of the copolymerizable monomer include vinyl acetate, ethylene, propylene, (meth)acrylic acid ester,
Maleic acid ester, vinyl ether, etc. are mentioned, and the copolymerizable monomer in the copolymer is 20% by weight.
It is preferable that it is below. In addition, the above-mentioned plasticizer can be one that has been generally used as a plasticizer for vinyl chloride resins, such as dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, etc. The amount may be appropriately determined depending on the degree of softness of the film, and it is generally preferable to add 10 to 70 parts by weight per 100 parts by weight of the vinyl chloride resin. The resin binder used in the present invention can be a resin that can bind conductive powder and is generally used as a paint, such as acrylic, vinyl, carbonate, polyester, urethane, epoxy, etc. Among them, vinyl chloride resins and acrylic resins are preferably used from the viewpoint of adhesion to the vinyl chloride resin film. The liquid plasticizer used in the present invention is a liquid plasticizer generally used for vinyl chloride resin, such as dioctyl phthalate, digtylphthalate, tricresyl phosphate, dioctyl phthalate, etc. Examples include adipate. The conductive powder used in the present invention is a white or gray-white powder, such as a conductive zinc oxide powder obtained by doping zinc oxide powder with aluminum, a conductive tin oxide powder obtained by doping tin oxide powder with antimony, etc. Examples include conductive powders in which a layer of a conductive substance such as the above conductive zinc oxide powder or conductive tin oxide powder is formed on the surface of titanium powder. As the particle size increases, the surface smoothness of the paint layer decreases, so the average particle size is preferably 1 μm or less, more preferably 0.5 μm or less. The antistatic coating layer in the present invention is a layer consisting of the above-mentioned resin binder, liquid plasticizer, and conductive powder, and when the amount of plasticizer added decreases, the plasticizer in the vinyl chloride resin film migrates and deteriorates over time. Resin binders will reduce the anti-electrostatic effect, make the paint layer harder, and cause cracks.
It is preferably added in an amount of 10 to 70 parts by weight, more preferably 20 to 60 parts by weight, per 100 parts by weight.
Furthermore, it is preferable that the content be approximately the same as the content of the vinyl chloride resin film. In addition, if the amount of conductive powder added is too small, the surface resistance will increase and the antistatic effect will be lost; if it is too large, the formability of the sheet and the smoothness of the surface of the paint layer will decrease, and the antistatic effect will not improve. It is added in an amount of 70 to 350 parts by weight, preferably 100 to 250 parts by weight, per 100 parts by weight of the resin binder and liquid plasticizer. In addition, in order to improve the dispersibility of the conductive powder, the coating layer contains silane coupling agents, titanate coupling agents, surfactants, dispersion aids such as oleic acid and lecithin, ultraviolet absorbers, stabilizers, etc. May be added. In the present invention, the paint layer is laminated on at least one surface of the soft vinyl chloride resin film, and any method may be used for the lamination. For example, methyl ethyl ketone, toluene, ethyl acetate, cyclohexanone, etc. By dispersing a resin binder, liquid plasticizer, and conductive powder in an organic solvent, applying it to at least one surface of the resin film by a method such as a spray method, a roll coating method, a bar coating method, or a gravure printing method, and drying it. One method is to form the Further, the antistatic film or sheet of the present invention is opaque, and it is sufficient if at least one of the vinyl chloride resin film and the antistatic coating layer is opaque, but it is preferable that the antistatic coating layer is opaque. The paint layer is substantially opaque due to the addition of conductive powder, but if the opacity is insufficient, it is preferable to add a powder having hiding power to the paint layer or vinyl chloride resin film. Examples of powders having hiding power include titanium oxide, calcium carbonate, and coloring pigments such as red red, cadmium yellow, ultramarine blue, navy blue, and chromium oxide when coloring red, blue, etc. Further, in order to color the antistatic film or sheet of the present invention, a colorant such as a dye such as oil yellow, oil orange, oil red, anthraquinone violet, or anthraquinone glue may be added. [Effects of the Invention] The structure of the antistatic film or sheet of the present invention is as described above, and since both the vinyl chloride resin film and the antistatic paint layer contain a plasticizer, the plasticizer in the vinyl chloride resin film is does not transfer to the antistatic paint layer, and the antistatic effect is excellent without decreasing over time. In addition, since the conductive powder to be added is white or grayish-white, the color of the film or sheet is white or grayish-white, and by adding a coloring agent, it can be beautifully colored in red, blue, etc., and can be used in clean rooms, etc. It can be suitably used as a packaging material for curtains and IC products. [Example] Next, an example of the present invention will be described. Examples 1 to 3, Comparative Examples 1 and 2 The compositions shown in Table 1 were supplied to a ball mill and dissolved and dispersed for 60 hours to obtain antistatic paints.
The obtained paint was applied to one side of a soft vinyl chloride resin film (thickness 0.3 mm) with the composition shown in Table 1 using a wire bar coater so that the thickness after drying was 2μ, and then dried to prevent static electricity. I got the film. The surface resistivity of the obtained film was measured immediately after drying, after 30 days, and after 90 days in accordance with ASTM D-257,
The results are shown in Table 1.

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Claims (1)

[Scope of Claims] 1. An antistatic paint layer consisting of a resin binder, a liquid plasticizer, and white or gray-white conductive powder is laminated on at least one surface of a soft vinyl chloride resin film, and an opaque soft antistatic film or sheet. 2. The antistatic film or sheet according to claim 1, wherein the amount of the liquid plasticizer added is 10 to 70 parts by weight per 100 parts by weight of the resin binder. 3. The antistatic film or sheet according to claim 1 or 2, wherein the conductive powder is added in an amount of 70 to 350 parts by weight per 100 parts by weight of the resin binder and liquid plasticizer.