JP2965349B2 - Antistatic film - Google Patents

Description

The present invention relates to an antistatic film suitable as a packaging film or the like.

[Prior Art and Problems to be Solved by the Invention] Various plastic films such as a polypropylene film, a polyethylene terephthalate film, and a nylon film have been used as packaging films for foods and the like. These plastic films generally have high electrical insulation properties, and thus are easily charged with static electricity. Therefore, an antistatic film coated with the plastic film and a coating solution containing an antistatic agent is provided.

However, even when the coating liquid is applied to a hydrophilic substrate film such as a nylon film, it is difficult to impart high antistatic properties. 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 a high antistatic property for a long period of time even if it is a hydrophilic substrate film.

[Constitution of the Invention] As a result of intensive studies, the present invention has been applied to a hydrophilic substrate film,
When applying a coating solution containing an antistatic agent, because the base film has hygroscopicity, the antistatic agent is made based on the base material, both sides of the nylon film are subjected to corona discharge treatment, one of An antistatic layer containing a hydrophobic polymer selected from chlorinated polyolefin and vinyl chloride-vinyl acetate copolymer and an antistatic agent is directly formed on the corona discharge treated surface, and the other corona is coated with an organic solvent coating solution. On the discharge treatment surface, a film in which a gas barrier layer containing a vinylidene chloride-based polymer is directly formed, the ratio of the hydrophobic polymer and the antistatic agent is 5 to 50: 50 to 95.
(Weight ratio) is provided.

The nylon film of the present invention can be used in a wide temperature range. As the nylon constituting the nylon film, for example, nylon 6, nylon 11, nylon 12, nylon
66, nylon 610, nylon 612 and copolymerized nylon such as nylon 6/66, nylon 66/610, nylon 6/11 and the like, and at least one of these nylons is used.

The nylon film may be stretched uniaxially or biaxially at an appropriate magnification by stretching means such as roll stretching, rolling stretching, belt stretching, tenter stretching, and tube stretching. The nylon film may be a single-layer film or a composite film in which two or more films are laminated. The thickness of the nylon film is not particularly limited, and is, for example, about 1 to 250 μm.

Both surfaces of the nylon film are surface-treated. As a surface treatment, a corona discharge treatment is preferable.

The nylon film may contain various additives such as an antioxidant, an ultraviolet absorber, a crystallization agent, a lubricant, a dye and a pigment.

An antistatic layer containing a hydrophobic polymer selected from chlorinated polyolefin (eg, chlorinated polypropylene) and vinyl chloride-vinyl acetate copolymer and an antistatic agent is formed on one surface of the nylon film. I have. This antistatic layer is formed directly on the surface-treated surface of the nylon film. When the antistatic layer is formed directly on the treated surface of the nylon film, even if printing ink is printed on the antistatic layer or another film is laminated, the adhesion to the printing ink and the lamination strength do not decrease.

The antistatic agent is a conventional antistatic agent, for example, is not particularly limited as long as it is ionic or nonionic, and imparts conductivity, cationic, anionic,
Both amphoteric and nonionic antistatic agents can be used.

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

Examples of the anionic antistatic agent include aryl sulfonates such as naphthalene sulfonate; alkyl aryl sulfonates such as dodecylbenzene sulfonate;
Fatty acid salts such as sodium oleate and potassium oleate; sulfuric acid derivatives such as sodium lauryl sulfate; triethanolamine salts of polystyrenesulfonic acid; Among these anionic antistatic agents, alkylaryl sulfonates and the like are preferable.

Examples of the amphoteric antistatic agent include alkyl betaines such as dimethylalkyl betaine; alanine derivatives; imidazoline derivatives such as calcium salts of imidazoline-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 preferable.

Examples of the nonionic antistatic agent 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 citrate, sorbitan tristearate, sorbitan monooleate and sorbitan trioleate; diethylene glycol monostearate, diethylene glycol monooleate, polyoxyethylene mono or diolate, polyoxyethylene mono or distearate, polyoxy Ethylene glycerin monostearate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate Polyoxyethylene fatty acid esters and polyoxyethylene sorbitan fatty acid esters and the like the like. Among these nonionic antistatic agents, ethylene oxide adducts of alkyl phenols, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and the like are preferable.

Among the above various antistatic agents, a cationic antistatic agent and an amphoteric antistatic agent are preferable.

These antistatic agents may be the same or different, and may be used alone or in combination of two or more.

The ratio of the hydrophobic polymer and the antistatic agent in the antistatic layer is determined by the ratio of the hydrophobic polymer / antistatic agent = 5 to 50/50.
~ 95 (weight ratio), preferably 10-40 / 60-90 (weight ratio)
It is about. When the content of the antistatic agent is out of the above range, the antistatic agent is likely to deteriorate due to the permeation of the antistatic agent into the nylon film.

The antistatic layer may contain an isocyanate-based, epoxy-based, polyethyleneimine-based adhesive or the like in order to further increase the adhesion to the nylon film.

Further, the antistatic layer may contain additives such as an antioxidant, an ultraviolet absorber, a heat stabilizer, an organic or inorganic filler, a dye pigment, and a viscosity modifier.

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

As the lubricant, wax or fine powder lubricant is preferable,
Examples of the wax include hydrocarbon waxes such as paraffin wax, polyethylene wax and microcrystalline wax, fatty acid waxes such as stearic acid, monoglyceride stearate, triglyceride stearate, zinc stearate, calcium stearate, oleic acid amide, and stearin Various waxes such as fatty acid amide waxes such as acid amide, erucamide, methylene bisstearic acid amide and ethylene bisstearic acid amide, and ester waxes such as carnauba wax can be exemplified. At least one of the above waxes is used. When the wax is contained in the antistatic layer, the content of the wax is usually 1 to 150 parts by weight, preferably 25 to 125 parts by weight, more preferably 50 to 100 parts by weight, based on 100 parts by weight of the hydrophobic binder. Parts.

As fine powder lubricant, for example, kaolin, talc,
Inorganic lubricants such as diatomaceous earth, titanium oxide, calcium carbonate, magnesium carbonate, barium sulfate, silica, and alumina; organic lubricants such as polyethylene, polypropylene, polystyrene, acrylic resin, silicone resin, and phenolic resin; alumina valves, silica balloons, and foamed glass ,
A micro hollow body such as a micro balloon and Saran microsphere is exemplified. Among these fine powdery lubricants, silica fine powder, alumina fine powder, polyethylene fine powder,
Acrylic fine powder is preferred. The fine powdery lubricant may have an appropriate particle size in a range that does not impair transparency or the like,
It is preferably 5 μm or less. When the particle size exceeds 5 μm, the lubricant tends to be missing, and the workability during packaging and the like is reduced. The content of the fine powdery lubricant is usually 1 to 50 parts by weight, preferably 5 to 4 parts by weight, based on 100 parts by weight of the hydrophobic polymer.
0 parts by weight, more preferably about 10 to 30 parts by weight.

The thickness of the antistatic layer is not particularly limited, but is usually about 0.001 to 5 μm, preferably about 0.01 to 2.5 μm, and more preferably about 0.05 to 2 μm. 0.001μm thick
If it is less than 5 μm, the antistatic effect is reduced. If it exceeds 5 μm, it is not economical, and in some cases, the properties of the nylon film may be reduced.

In the antistatic film of the present invention, the antistatic layer is directly formed on one surface of a nylon film having both surfaces subjected to corona discharge treatment, and the gas barrier layer containing a vinylidene chloride-based polymer is directly formed on the other corona discharge treatment surface. Is formed. When a gas barrier layer is formed on the other surface of the nylon film, the influence of moisture can be reduced, and a high antistatic property can be imparted to the nylon film. Examples of the vinyldene chloride-based polymer include polyvinylidene chloride and vinylidene chloride.
Vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-vinyl acetate copolymer, vinylidene chloride-acrylic acid copolymer, vinylidene chloride
Polymers such as methacrylic acid copolymers, vinylidene chloride-acrylic acid ester copolymers, and vinylidene chloride-based resins such as vinylidene chloride-methacrylic acid ester copolymers can be used. The gas barrier layer may contain an additive such as an additive 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 is subjected to corona discharge treatment on both sides of a nylon film, and directly applying a coating solution containing the antistatic agent and the hydrophobic polymer to one surface,
It can be produced by directly applying an organic solvent coating solution containing a vinylidene chloride-based polymer to the other surface. The coating liquid containing the antistatic agent may be aqueous or oily containing an organic solvent. As the organic solvent, for example, alcohols, aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ketones, esters, ethers and the like and a mixed solvent thereof are used. . The coating liquid can be prepared using a general mixer.

By applying the coating liquid to the nylon film using a conventional coating means, for example, a dip coater, a roll coater, a flow coater, a knife coater, a gravure coater, an air knife coater, an application means such as a spray, and drying. An antistatic film is obtained.

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

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

Reference Examples 1 to 3 and Comparative Examples 1 to 4 One surface of a nylon 6 film having a thickness of 15 μm was subjected to a surface treatment to a surface tension of 40 dyn / cm by corona discharge.

Also, a mixture of chlorinated polypropylene and sodium dodecylzensulfonate in the proportions shown in the table, 8 parts by weight of silica fine powder, and a mixed solvent of ethyl acetate-toluene (2: 1 by weight) was applied at a solid concentration of 0.4% by weight. A liquid was prepared. Then, a coating liquid was applied to the treated surface of the film so as to have a coating amount after drying of 0.05 g / m ^2, and dried to form an antistatic layer.

Example 1 Both surfaces of the biaxially stretched nylon film used in Reference Example 1 were subjected to surface treatment in the same manner as in Reference Example 1. On one side of this film, the coating solution of Reference Example 2 was applied in an amount of 0.05 g / m ² after drying.
And dried to form an antistatic layer.

Further, 100 parts by weight of a vinylidene chloride (90% by weight) -acrylate (10% by weight) copolymer (melting point: 145 ° C.), 1 part by weight of a wax having a melting point of 78 ° C., and an average particle size of 3 μm as a lubricant
0.1 parts by weight of silica fine powder of
A coating solution was prepared by uniformly mixing toluene / 70/30 (weight ratio). This coating solution was applied to the other surface of the nylon film so as to have a coating amount after drying of 2.0 g / m ² , thereby forming a gas barrier layer.

Reference Example 5 Instead of the coating liquid of Reference Example 1, a coating liquid 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 silica fine powder was used. Coating and drying were performed in the same manner as in Reference Example 2 to form an antistatic layer.

The antistatic properties of the sample films obtained in the above Examples, Reference 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.

As is clear from the table, when the ratio between the hydrophobic binder and the antistatic agent is 50:50 to 10:90 (weight ratio), all of them have excellent antistatic properties.

Claims (1)

(57) [Claims] A nylon film is subjected to corona discharge treatment on both sides, and one of the corona discharge treated surfaces contains a hydrophobic polymer selected from chlorinated polyolefin and vinyl chloride-vinyl acetate copolymer and an antistatic agent. An anti-static layer is formed directly, and a gas barrier layer containing a vinylidene chloride-based polymer is directly formed on the other corona discharge treated surface by an organic solvent coating liquid, wherein the hydrophobic polymer and an antistatic agent An antistatic film having a ratio of 5 to 50:50 to 95 (weight ratio).