JPH0493247A - Antistatic film - Google Patents

Abstract

PURPOSE:To improve the resistance to elevated temperature, friction, solvents and the adherence between the film concerned and other film by a method wherein thin film containing graft polymer, which is produced by graft- copolymerizing one or more kinds of sulfonic salt group-containing unsaturated monomer and polyester having specified molecular weight, is provided on at least one side of plastic film. CONSTITUTION:Thin film containing graft polymer, which is produced by graft- copolymerizing one or more kinds of sulfonic salt group-containing unsaturated monomer and polyester having the mean molecular weight of 2,000 or more, is provided on at least one side of plastic film. As the plastic film, polyester film such as polyethylene terephthalate film, polyethylene-2,6-naphthalate film or the like is especially preferable. As the acid component of polyester, terephthalic acid, isophthalic acid or the like exemplified. As the sulfonic salt group-containing unsaturated monomer, sodium vinylsufonate, sodium methallylsulfonate or the like is exemplified. The ratio of main chain polyester to graft side chain is preferably 10/90-90/10 in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an antistatic film, and more particularly, to a magnetic recording medium that exhibits stable antistatic properties.

Used as an antistatic film useful for general electronic materials, cards, etc.

<Prior Art> Plastic films have excellent mechanical properties, heat resistance, gas barrier properties, chemical resistance, etc., and are used in a wide range of fields, but they have the drawback of having a large surface resistivity and being easily charged. For example, a polyester film that has been stretched and heat-set on two wheels has a surface resistivity value of 10t5 to 1017Ω/unit and is easily charged, which tends to cause troubles such as foreign matter adsorption in magnetic recording media and electronic materials.

Conventionally, a method for preventing static electricity on a film is to apply an antistatic paint. Methods and methods of kneading an antistatic agent into a base polymer are known.

The most well-known type of antistatic agent is a low-molecular-weight surfactant type, but this type tends to ooze out onto the film surface and stick to it, or is easily removed by friction, making it less effective. It shows a tendency to be lost. Polymer types are also known, but they decompose at temperatures above 180°C, have limited ionicity, and are often unusable due to rusting properties. Furthermore, even if it has antistatic properties, it cannot be put to practical use if it lacks adhesion to the film.

<Object of the Invention> An object of the present invention is to provide an antistatic film that exhibits stable antistatic properties and is useful for magnetic recording media, general electronic materials, cards, and the like. Another object of the present invention is to
．． The object of the present invention is to provide an antistatic resin that has excellent resistance to scratches and solvents, has high adhesion to films, and exhibits stable antistatic properties.

<Configuration/Effects of the Invention> According to the present invention, the objects of the present invention are as follows: 1. At least one side of the plastic film has an average molecular weight of 2.0.
2. An antistatic film comprising 1 ml of a graft polymer obtained by graft copolymerizing one or more sulfonic acid group-containing unsaturated monomers to a polyester of 0.00 or more, and 2. An average molecular weight of 2,000. This is achieved by using an antistatic resin mainly composed of a graft polymer obtained by graft copolymerizing one or more sulfonic acid group-containing unsaturated monomers to the above polyester.

Plastic films in the present invention include polyester films (e.g., polyethylene terephthalate films, polyethylene-2,6-naphthalate films, etc.), polyolefin films (e.g., polyethylene films, polypropylene films, etc.), nylon films, polycarbonate films, polyvinyl chloride films. For example, polyester film is particularly preferred.

The plastic film may be an unstretched film, a -axially stretched film, or a two-wheel stretched film, but a two-wheel stretched film is particularly preferred.

The graft polymer in the present invention has an average molecular weight of 2.00
It is a polymer in which the main chain component is 0 or more polyesters, and one or more sulfonic acid group-containing unsaturated monomers are graft-copolymerized therewith. Examples of acid components of the polyester include terephthalic acid, inphthalic acid, adipic acid, sebacin 1.5-Na sulfoisophthalic acid, maleic acid, and fumaric acid, and examples of dihydroxy compound components include ethylene glycol, propylene glycol, and 1.4-Na sulfoisophthalic acid. -butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 2-methyl-2-
Carboxy-1,3-propanediol.

Examples include polyethylene glycol, ethylene oxide adduct of bisphenol A, 1,4-cyclohexane dimetatool, and p-xylylene glycol. The number average molecular weight of the polyester is 2,000 or more, preferably s,
It's more than ooo. If the number average molecular weight is less than 2,000, the adhesion will be poor, which is not preferable. Further, polyester has an intrinsic viscosity (0-chlorophenol, 35°C) of 0.
2 to 0.8, and the breaking strength is 100 to 600 kM c
m, and those having a breaking elongation of 50 to 500% are preferable. Polyester can be produced by conventional methods.

Examples of the sulfonic acid group-containing unsaturated monomer to be graft copolymerized with such polyester include sodium vinylsulfonate and sodium methallylsulfonate.

Examples include sodium styrene sulfonate, ammonium vinyl sulfonate, potassium methallyl sulfonate, and lithium styrene sulfonate. One or more types of these can be used. The sulfonic acid group-containing unsaturated monomer can be used in combination with small proportions of other unsaturated monomers, if desired. Graft copolymerization of unsaturated monomers containing sulfonic acid groups can be carried out by conventional methods, such as bulk polymerization and solution polymerization.

Emulsion polymerization, suspension polymerization, etc. can be used. The molecular weight of the graft side chain is preferably 500 or more.

The ratio of main chain polyester to graft side chain is 1 by weight.
The ratio is preferably 0/90 to 90/10.

It is preferable that the antistatic resin in the present invention is finally put to practical use in the form of an organic solvent solution or an aqueous liquid (aqueous solution, aqueous dispersion, etc.). More water-based liquids.

It is particularly preferable to use it in the form of an aqueous dispersion.

At that time, other resins, other antistatic agents, pigments, and W4 agents.

Other additives such as filler 2 dispersants, conductive materials, etc. can be added if desired.

The coating liquid containing antistatic resin is an unstretched film.

- Applied to axially stretched film or two-wheel stretched film,
Stretching treatment may be performed after coating. Application can be performed by roll coating, gravure coating, etc.

The antistatic film obtained in this way has a small surface resistivity value, for example, 109 to 10r3Ω/mouth, or even 1
It has a surface resistivity of 010 to 1013 Ω/portion, and can prevent adhesion of foreign matter and sticking due to static electricity.

Furthermore, the coating layer has excellent heat resistance and adhesion. Antistatic film is a magnetic recording medium! ! Temperature recording cards, film for plate making, leader tapes.

It can be preferably used for applications such as OHP films and S thermal transfer ribbons.

<Example> The present invention will be further explained below with reference to Examples.

The film properties in the examples were measured using the following method. Surface resistivity was measured by depositing aluminum on a 8 cm square film sample and heating it at 20°C.
The surface resistivity (Ω/hole) was measured using a high-voltage power supply resistor and a vibrating capacitance microcurrent electrometer under conditions of , 50% RH.

(2) Apply 1μ (D
ry> thickness, then press cellophane tape onto the magnetic paint layer with a roller, remove the tape with beer,
The peel strength of the magnetic paint layer was measured.

(Magnetic paint) Nitrocellulose R81/2 as lacquer thinner for paint
(Freus containing 25% isopropanol, manufactured by Daicel) to prepare a 40 wt% solution, and the solution 43
．． 8 parts by weight, followed by polyester resin (1 part by weight)
F00. 32.5 parts by weight (manufactured by Bayer AG), 200 parts by weight of chromium dioxide powder, and as a dispersant/wetting agent, soybean oil fatty acid Lesion P (manufactured by Riken Vitamin ■), cationic activator (Cation AB, manufactured by NOF ■) and 1 part and 0.51 parts of squalene (shark liver oil), respectively.

Pour 0.8 parts by weight into a ball mill and mix methyl ethyl ketone/cyclohexycanone/toluene - 3/4/3 (weight ratio)
Further, 282 parts by weight of a mixed solvent consisting of the following were further mixed and sufficiently pulverized to prepare a mother liquor paint (45 wt%). To 50 parts by weight of this mother liquor, 48 parts by weight of trimethylolpropane and toluylene diisocyanate addition reaction part (Coronate L: manufactured by Nippon Polyurethane Industry ■) and 6.2 parts by weight of butyl acetate.
5 parts by weight were added to obtain a final magnetic coating material with a concentration of 42.75 wt%.

(3) Adhesive properties of UV-curable ink After printing UV-curable printing ink (Flash Dry FDO Beni APN manufactured by Toyo Ink) on a polyester film with an easy-to-adhesive layer using an RI tester (Mei Seisakusho), Curing was performed using a medium-pressure mercury lamp (80 W/C1, type 2 manufactured by Nippon Battery) with a UV curing device to form a UV ink layer with a thickness of 7.0 μm.

Evaluation 1): A cellophane tape with a width of 181111 (manufactured by Chiban) was pasted on top of this ink layer, reverse peeled at 180° at a high speed of 100 m / 1 n, and the peeling state was observed, and the peeling load (9 /18vs) to indicate adhesion.

Evaluation 2): On this UV ink layer, make a cut with a cutter knife, apply cellophane tape roughly, perform normal peeling at 90 degrees, and indicate the peeling condition in 5 stages (Good: 5) ←1: Evil).

Example 1 Isophthalic acid (82 o1%), Malein I (4-01
%), 5-Na sulfoisophthal%), adipic acid (1
acid component of 0so1%) and ethylene glycol (10i
o1%), 1,4-butanediol (70mol1%),
Number average molecular weight 21,000 made from diethylene glycol (20mol1%) and dihydroxy compound component
18 parts by weight of co-polyester (intrinsic viscosity 0.52) was dissolved in tetrahydrofuran (THF), 2 parts by weight of polyethylene glycol nonylphenyl ether (number of moles of ethylene oxide added: 40) was added, and 80 parts by weight of water was mixed. Copolymerized polyester fine particles were precipitated, and then THF was distilled off to obtain 100 parts by weight of an aqueous dispersion. Add 0.3 parts by weight of sodium dodecylbenzenesulfonate to 100 parts by weight of this aqueous dispersion, stir thoroughly, heat the solution to 10°C, and 22 parts by weight of sodium methallylsulfonate monomer under nitrogen gas atmosphere. , sodium persulfate 0
．． 20 parts by weight of 5% aqueous solution, 0.0 parts by weight of sodium metabisulfite.
Add 20 parts by weight of a 5% aqueous solution, stir for 6 hours while maintaining at 10°C, and perform emulsion polymerization to determine the polyester/vinyl polymer ratio -
A graft copolymer emulsion of 45155 (weight ratio) and a softening point of 70°C was obtained, and this was diluted to obtain a concentrated IJ! A 4% coating liquid (A) was prepared.

Polyethylene terephthalate (Ti) with an intrinsic viscosity of 0.66
02-containing) was melt-extruded onto a rotating cooling drum maintained at 23°C to form an unstretched film, and then the unstretched film was stretched 3.5 times in the machine axis direction, and then the coating liquid (A) was applied to both sides of the film. Each was applied in an amount of 29/- (wet) by the kiss coat method. Continue to 3.9 in the horizontal direction at 106℃
The film was stretched twice to obtain a double-sided coated film having a thickness of 185 μm.

Surface specific resistance of one side ρs = 3.9×10”Ω/mouth,
The value of ρB on the other side was −4.2×10 11 Ω/mouth. or,
The adhesive strength of the magnetic paint is 5191/C on one side and 53g/on the other side.
It was C-. Adhesion to UV curing ink is 550g/18gn in evaluation 1).

Evaluation 2) was 5.

A magnetic card obtained by applying a magnetic paint containing magnetic iron oxide on one side of the film thus obtained and printing UV curing ink on the other side had no defects due to foreign matter and had excellent durable adhesive strength.

Example 2 The same procedure as Example 1 was carried out except that the weight ratio of polyester/vinyl polymer in the preparation of coating liquid (A) was changed to 52/48. Surface specific resistance ρs on one side of the obtained film -1,8X 10I2Ω/mouth, ρS on the other side =
It was 1.9×10 12 Ω/mouth. The adhesive strength of the magnetic paint was 539/cs on one side and 60g/cs on the other side.

Example 3 Example 1 except that the weight ratio of polyester/vinyl polymer in coating liquid (A) made by II was changed to 38/62.
I did the same thing. Surface specific resistance ρs on one side of the obtained film -1,5X10''Ω/mouth, ρS on the other side = 1゜3
The adhesive force of the magnetic paint was 49 g/CI on one side and 469/C- on the other side.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the coating liquid was not applied. Surface specific resistance of the obtained film ρS-8,7X10
I5Ω/mouth. Also, the adhesive strength of the magnetic paint is 18g/
It was c-. Adhesion to UV curing ink was 1009/1811 in evaluation 1). Piii 2) was 1.

Example 4 According to the preparation method of coating liquid (A), terephthalic acid 77so1
%), maleic acid (5 gardens of %), 2-sulfoterephthal 59 (3g+O1%), sebacin i! (5101%
), the acid component of adipic acid (10so1%), and 1.4-
Butanedio-J Shikushi 80101%), Bisphenol A
with a dihydroxy compound component of ethylene oxide adduct (201101%) with a number average molecular weight of 19.5
Sodium vinyl sulfonate (501101%), lithium styrene sulfonate (501%) in the presence of 00 polyester
0io1%) was subjected to radical polymerization to prepare a graft copolymer emulsion with a weight ratio of polyester/vinyl polymer = 50/50, and a coating liquid (B) with a concentration of 4% was prepared.

The following steps were carried out in the same manner as in Example 1. The surface resistivity of one side of the obtained film was ρS -3.8 x 10''Ω/hole, and the other side was ρs -3.9X 10''Ω/hole. Also, the adhesive strength of the magnetic paint is 52 on one side! J/CI, other side 559/CI
Met.

Example 5 Terephthal 1j (6710
1%), isophthalic acid (10so1%), maleic acid 1 (
5■01%), sebacic acid (18-01%), and the addition of ethylene oxide to ethylene glycol (20101%), 1,4-butanediol (60101%), and bisphenol A. Number average molecular weight 18,000 made from dihydroxy compound component of J (20so1%)
A graft copolymer emulsion with a polyester/vinyl polymer ratio of -48152 (weight ratio) was prepared by radical polymerization of sodium methallylsulfonate in the presence of a polyester of 4%, and a coating liquid (C) with a concentration of 4% was prepared. .

The following steps were carried out in the same manner as in Example 1. The surface resistivity ρs on one side of the obtained film was 4.2×10”Ω/hole, and the surface resistivity on the other side was −4.1×tollΩ/hole.

Example 6 The above coating liquid (C) (4% concentration) and acrylic resin emulsion [Brimal AC-604j (4% concentration) 65
/35 (weight ratio) and make a coating liquid with a concentration of 4% (
D).

The following steps were carried out in the same manner as in Example 1. The surface resistivity of one side of the obtained film was ρs -8,9×10I2Ω/hole, and the other side was ρs=9,6×10I2Ω/hole.

Patent applicant Teijin Kaisha Ltd.

Claims (1)

[Claims] 1. A thin layer containing a graft polymer obtained by graft copolymerizing one or more sulfonic acid group-containing unsaturated monomers to a polyester having an average molecular weight of 2,000 or more on at least one side of the plastic film. An antistatic film characterized by the following: 2. The antistatic film according to claim 1, wherein the plastic film is a polyester film. 3. An antistatic resin mainly composed of a graft polymer obtained by graft copolymerizing a polyester having an average molecular weight of 2,000 or more with one or more sulfonic acid group-containing unsaturated monomers.