JPH04201250A - Antistatic film - Google Patents

Abstract

PURPOSE:To keep high antistatic properties even in a hydrophilic base material film over a long period of time by mixing a hydrophobic polymer with an antistatic agent in a specific ratio to apply the resulting mixture to the hydrophilic base material film. CONSTITUTION:An antistatic layer wherein the wt. ratio of a hydrophobic polymer and an antistatic agent is 5-50:50-95 is formed to at least one surface of a hydrophilic base material film. As the hydrophilic base material film, for example, various films formed from a polyvinyl alcohol type polymer, an ethylene/vinyl alcohol copolymer or the like can be used. As the hydrophobic polymer, for example, polyolefin, chlorinated polyolefin, a styrenic resin and a vinylidene chloride type resin are used and, as the antistatic agent, a usual antistatic agent, for example, an ionic or nonionic one is used and there is no limit if an antistatic agent imparting conductivity is used and all of cationic, anionic, amphoteric and nonionic antistatic agents can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an antistatic film suitable as a packaging film or the like.

[Problems to be solved by the prior art and the invention 1 Various plastic films such as polypropylene film, polyethylene terephthalate film, and nylon film are used as packaging films for foods and the like. Since these plastic films are generally electrically insulating or large, they are easily charged with static electricity. Therefore, an antistatic film is provided in which the plastic film is coated with a coating liquid containing an antistatic agent.

However, even when the coating liquid is applied to a hydrophilic base film such as a nylon film, it is difficult to impart high antistatic properties. Moreover, even if antistatic properties can be imparted, it is difficult to maintain the effect.

Therefore, an object of the present invention is to provide an antistatic film that maintains high antistatic properties over a long period of time even if it is a hydrophilic base film.

[Structure of the Invention] As a result of intensive research, the present inventor has discovered that the hydrophilic base film has the following properties:
It has been found that when a coating solution containing an antistatic agent is applied, the antistatic agent permeates into the base film and the antistatic property disappears, probably because the base film has hygroscopic properties. The present invention has been made based on the above findings, and provides a film in which an antistatic layer containing a hydrophobic polymer and an antistatic agent is formed on at least one surface of a hydrophilic base film, the film comprising: Provided is an antistatic film in which the ratio of a hydrophobic polymer to an antistatic agent is 5 to 50:50 to 95 (weight ratio).

As the hydrophilic base film, various films made of materials such as polyvinyl alcohol polymer, ethylene-vinyl alcohol copolymer, nylon or polyamide, and cellophane can be used.

Among the above hydrophilic base films, films that can be used in a wide temperature range, such as nylon films, are preferred. Examples of nylon constituting the nylon film include:
Nylon 6, Nylon 11, Nylon 12, Nylon 6
6. Nylon 610, nylon 612, copolymerized nylon, such as nylon 6/66, nylon 66/610
, nylon 6/11, etc., and at least one of these nylons is used.

The base film can be rolled stretched, rolled stretched, belt stretched,
It may be uniaxially or biaxially stretched to an appropriate magnification by a stretching means such as tenter stretching or tube stretching. Further, the base film may be a single layer film or a composite film in which two or more types of films are laminated. The thickness of the base film is not particularly limited, and is, for example, about 1 to 250 μm thick.

Moreover, it is preferable that at least one surface, particularly both surfaces, of the base film be surface-treated. As for surface treatment,
Examples include corona discharge treatment, high frequency treatment, flame treatment, chromic acid treatment, and solvent treatment. Among these surface treatments, corona discharge treatment is preferred.

In addition, the above base film contains antioxidants, ultraviolet absorbers,
It may contain various additives such as crystal nucleating agents, lubricants, and dyestuffs.

An antistatic layer containing a hydrophobic polymer and an antistatic agent is formed on at least one surface of the base film. This antistatic layer is preferably formed on the surface-treated surface of the base film. When forming an antistatic layer on the treated surface of the base film, the adhesion with the printing ink and lamination strength will not decrease even if printing ink is printed on the antistatic layer or other films are laminated. .

Examples of the hydrophobic binder include polyolefins such as polyethylene and polypropylene, ionomers, ethylene-vinyl acetate copolymers, acrylic resins, methacrylic resins, ethylene-acrylic acid ester copolymers, polyesters, polyurethanes, polyacetals, polyvinyl chloride, Chlorinated polyolefins such as polyvinylidene chloride and chlorinated polypropylene, cellulose resins, polystyrene, styrene resins such as styrene-acrylic copolymers, styrene-butadiene copolymers, and styrene-acrylonitrile copolymers, vinyl chloride-vinyl acetate Copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-vinyl acetate copolymer, vinylidene chloride-acrylic acid copolymer, vinylidene chloride-methacrylic acid copolymer, vinylidene chloride −
Examples include vinylidene chloride resins such as acrylic ester copolymers and vinylidene chloride-methacrylic ester copolymers.

These binders may be used alone or in combination of two or more.

The antistatic agent is not particularly limited as long as it is a conventional antistatic agent, such as one that is ionic or nonionic and imparts conductivity, and includes cationic, anionic, amphoteric, and nonionic antistatic agents. Any antistatic agent can be used.

Examples of the cationic antistatic agent include polyoxyethylene alkylamine; hydantoin derivatives; pyridinium derivatives such as laurylpyridinium bromide; alkyltrimethylammonium chlorides such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, and octadecyltrimethylammonium chloride; dialkyl Examples include quaternary ammonium salts such as dimethylammonium chloride, polyvinylbenzyltrimethylammonium chloride, and poly-2-acryloyloxyethyltrimethylammonium chloride; vinyl ether derivatives; acrylamide derivatives. Among these cationic antistatic agents, quaternary ammorum salts and the like are preferred.

Examples of anionic antistatic agents include aryl sulfonates such as naphthalene sulfonate; alkylaryl sulfonates such as dodecylbenzenesulfonate; fatty acid salts such as sodium oleate and potassium oleate; sodium lauryl sulfate, etc. sulfuric acid derivatives; triethanolamine salts of polystyrene sulfonic acid, etc. are exemplified. Among these anionic antistatic agents, alkylaryl sulfonates and the like are preferred.

Examples of the amphoteric antistatic agent include alkyl betaines such as dimethylalkyl betaine; alanine derivatives, imidacillin derivatives such as calcium salts of imidacillin type amphoteric surfactants, and metal salts of diamine type amphoteric surfactants. Among the amphoteric antistatic agents, alkyl betaine type antistatic agents and the like are preferred.

Examples of nonionic antistatic agents include polyhydric alcohols; ethylene oxide adducts of higher alcohols, ethylene oxide adducts of alkylphenols such as polyoxyethylene nonylphenyl ether; glycerin monostearate, glycerin monooleate, and sorbitan monostearate. Esters of polyhydric alcohols and fatty acids such as sorbitan tristearate, sorbitan monooleate, sorbitan triolate: diethylene glycol monostearate, diethylene glycol monooleate, polyoxyethylene mono- or diolate, polyoxyethylene mono- or distearate, polyoxy Examples include polyoxyethylene fatty acid esters and polyoxyethylene sorbitan fatty acid esters such as ethylene glycerin monostearate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan tristearate. Among these nonionic antistatic agents, ethylene oxide adducts of alkylphenols, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and the like are preferred.

Among the various antistatic agents mentioned above, cationic antistatic agents and amphoteric antistatic agents are preferred.

These antistatic agents may be used singly or in combination of two or more of the same or different types.

The ratio of the hydrophobic polymer to the antistatic agent in the antistatic layer is the above hydrophobic polymer/antistatic agent -5 to 5015.
0-95 (weight ratio), preferably 10-40/60-9
It is about 0 (weight ratio).

When the content of the antistatic agent is out of the above range, the antistatic property tends to deteriorate, probably because the antistatic agent penetrates into the hydrophilic base film.

The antistatic layer may contain an adhesive such as an isocyanate-based, epoxy-based, or polyethyleneimine-based adhesive in order to further improve the adhesion with the base film.

The antistatic layer may also contain additives such as antioxidants, ultraviolet absorbers, heat stabilizers, organic or inorganic fillers, dye pigments, and viscosity modifiers.

The antistatic film of the present invention preferably has anti-blocking properties and slip properties from the viewpoint of workability. This anti-blocking property and slip property may be imparted by forming an anti-blocking layer and a lubricant layer on the antistatic layer, but it is preferable that the antistatic layer contains a lubricant or the like.

As the lubricant, wax or finely powdered lubricant is preferable. Examples of waxes include hydrocarbon waxes such as paraffin wax, polyethylene wax, and microcrystalline wax, fatty acid waxes such as stearic acid, stearic acid monoglyceride, stearic acid triglyceride, zinc stearate, and calcium stearate, tux, and oleic acid amide. , stearic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, and other fatty acid amide waxes; and carnauba wax and other ester waxes. At least one of the above waxes is used. When wax is contained in the antistatic layer, the wax content is usually 1 to 150 parts by weight, preferably 25 to 125 parts by weight, and more preferably 50 to 100 parts by weight, based on 100 parts by weight of the hydrophobic binder. A part of the book.

Examples of fine powder lubricants include inorganic lubricants such as kaolin, talc, diatomaceous earth, titanium oxide, calcium carbonate, magnesium carbonate, barium sulfate, silica, and alumina;
Organic lubricants such as polyethylene, polyethylene, polystyrene, acrylic resin, silicone resin, phenolic resin,
Examples include micro hollow bodies such as alumina bulbs, silica balloons, foamed glass, microballoons, and Saran microspheres. Among these fine powder lubricants, silica-based fine powder, alumina-based fine powder, polyethylene-based fine powder, acrylic-based fine powder, etc. are preferred. The fine powder lubricant may have an appropriate particle size within a range that does not impair transparency etc.
It is preferable if it is below. If the particle size exceeds 5 μm, the lubricant is likely to be lost, reducing workability during packaging. The content of the fine powder lubricant is usually 1 to 50 parts by weight, preferably 5 to 40 parts by weight, and more preferably 10 to 30 parts by weight, based on 100 parts by weight of the hydrophobic binder.

The thickness of the antistatic layer is not particularly limited or is usually
0.001-5μm, preferably 0.01-2.5μm
1 More preferably, it is about 0.05 to 2 μm. If the film thickness is less than 0,001 μm, the antistatic effect will decrease, and 5
If it exceeds μm, not only is it not economical, but there is a possibility that the properties of the base film may deteriorate depending on the case.

In the antistatic film of the present invention, the antistatic layer is formed on one side of a hydrophilic base film, and a gas barrier layer containing a vinylidene chloride polymer is formed on the other side, especially the surface treated side. is preferable. By forming a gas barrier layer on the other surface of the base film, the influence of moisture can be reduced and high antistatic properties can be imparted to the base film. As the vinylidene chloride polymer, the polymers listed above can be used. This gas barrier layer may contain additives such as a lubricant, as described above.

The thickness of the gas barrier layer is usually about 0.1 to 5 μm, preferably about 0.5 to 2.5 μm.

The antistatic film of the present invention can be produced by subjecting at least one side of the base film to a surface treatment, if necessary, and applying a coating liquid containing the antistatic agent and a hydrophobic binder. I can do it. The coating liquid may be aqueous or oil-based containing an organic solvent. Examples of organic solvents used include alcohols, aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ketones, esters, ethers, and mixed solvents thereof. . The coating liquid can be prepared using a boat mixer.

The coating solution is applied using a conventional coating method such as a dip coater, roll coater, flow coater, knife coater, etc.
An antistatic film is obtained by coating the base film using a coating means such as a Clavia coater, an air knife coater, or a sprayer, and drying it.

[Effects of the Invention] The antistatic film of the present invention exhibits high antistatic properties over a long period of time, even though the base film is hydrophilic.

[Examples] The present invention will be described in more detail below based on Examples.

Examples 1 to 3 and Comparative Examples 1 to 4 One side of a 15 μm thick nylon 6 film was surface-treated to have a surface tension of 40 dyn/am by corona discharge.

In addition, chlorinated polypropylene and sodium dodecylnzene sulfonate in the proportions shown in the table, 8 parts by weight of fine silica powder, and a mixed solvent of ethyl acetate and toluene (weight ratio 2:1) were mixed, and the solid content concentration was 0.4 parts by weight. % coating solution was prepared.

Then, the coating liquid was applied to the treated surface of the film so that the coating amount after drying was 0.05 g/m2, and dried to form an antistatic layer.

Example 4 Both sides of the biaxially stretched nylon film used in Example 1 were
The surface treatment was carried out in the same manner as in Example 1. The coating solution of Example 2 was applied to one side of this film in an amount of 0.05 g/dry after drying.
An antistatic layer was formed by applying the solution to a thickness of m2 and drying.

In addition, 100 parts by weight of vinylidene chloride (90% by weight)-acrylic acid ester (10% by weight) copolymer (melting point 145°C), 1 part by weight wax having a melting point of 78°C, and fine silica powder with an average particle size of 3 μm as a lubricant. A coating solution was prepared by uniformly mixing 0.1 part by weight in tetrahydrofuran/toluene-70/30 (weight ratio). This coating liquid was applied to the other side of the nylon film so that the coating amount after drying was 2.0 g/m 2 to form a gas barrier layer.

Example 5 In place of the coating solution of Example 1, a coating solution consisting of methyl ethyne ketone, 20 parts by weight of vinyl chloride-vinyl acetate copolymer, 80 parts by weight of stearyltrimethylammonium chloride, and 5 parts by weight of fine silica powder was used, The antistatic layer was formed by coating and drying in the same manner as in Example 2 above.

The antistatic properties of the sample films obtained in each of the above Examples and Comparative Examples were evaluated by measuring the surface resistivity at a temperature of 20° C. and a humidity of 55% RH.

The results are shown in the table.

(Hereinafter, blank space) As is clear from the table, all examples in which the ratio of the hydrophobic binder to the antistatic agent was 50 + 50 to 10:90 (parts by weight) had excellent antistatic properties.

Claims (1)

[Scope of Claims] 1. A film in which an antistatic layer containing a hydrophobic polymer and an antistatic agent is formed on at least one surface of a hydrophilic base film, the hydrophobic polymer and the antistatic agent An antistatic film having a ratio of 5 to 50:50 to 95 (weight ratio). 2. Claim 1, wherein an antistatic layer containing a hydrophobic polymer and an antistatic agent is formed on one side of the hydrophilic base film, and a gas barrier layer containing a vinylidene chloride-based polymer is formed on the other side. The antistatic film described in .