JPH0632923A - Laminated film - Google Patents

Abstract

PURPOSE:To obtain a laminated film excellent in low-temp. antistatic property and water and solvent resistances by forming a layer of a composition containing a specific polymer and a blocked polyisocyanate on at least one side of a thermoplastic film. CONSTITUTION:A film of a thermoplastic resin is coated on at least one side thereof with a composition containing a polymer having active hydrogen and a quaternary nitrogen atom in the molecule (e.g. one obtained by copolymerizing methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate, and a quaternized dimethylaminoethyl methacrylate in a weight ratio of 47/21/7/25) and at least one blocked polyisocyanate (e.g. phenol-blocked tolylene diisocyanate). Thus, a thermoplastic film excellent in low-temp. antistatic property and water and solvent resistances can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic film which is transparent and has excellent water resistance and solvent resistance.

[0002]

2. Description of the Related Art Polyolefin, polyester,
Films made of thermoplastic resins such as polyamide, polystyrene and polyvinyl chloride, particularly oriented polypropylene, polyester, and films such as polyamide, have excellent mechanical properties, heat resistance, transparency, etc. It is widely used as a film for use in magnetic recording media, a base material for magnetic recording media, and a film for general industrial use. However, these films have a drawback that they are easily charged by static electricity because the resin itself is an insulator. Traditionally,
Various methods have been used to impart antistatic properties to these films. For example, a film having a surface having an antistatic property, an ionic compound, a conductive substance such as a metal powder or a metal oxide, or the like is kneaded into the film composition or blended in a coating agent. The method of applying it to was used. However, the method using a surfactant and an ionic compound as the antistatic agent has a problem that the antistatic property is lowered under low humidity. On the other hand, the method using a conductive substance does not have a problem that the antistatic property is lowered even in an environment of low humidity, but it is necessary to add a large amount of a conductive substance in order to impart the antistatic property, There was a problem that transparency was lowered.
Further, there is a problem that such a conductive material is expensive. Therefore, there has been a demand for the development of a thermoplastic film that is transparent and has excellent antistatic properties.

[0003]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a thermoplastic film excellent in antistatic property at low humidity, water resistance and solvent resistance. To provide.

[0004]

The laminated film of the present invention comprises a polymer comprising a thermoplastic resin and a polymer having active hydrogen and a quaternary nitrogen atom in the molecule on at least one side thereof.
A laminated film characterized by being coated with a composition containing at least one polyfunctional blocked isocyanate compound.

The thermoplastic film used in the present invention is not particularly limited as long as it is a thermoplastic resin capable of forming a transparent film, but olefin resins such as polyethylene and polypropylene, polyethylene terephthalate, polyethylene isophthalate, polyethylene 2 , 6 naphthalate, polybutylene terephthalate and polyester resins represented by their copolymers, polyether resins represented by polyoxymethylene, nylon-6, nylon-6
6. Polyamide resin represented by polymeta-xylene adipamide, polystyrene, poly (meth) acrylic acid ester, polyacrylonitrile, polyvinyl acetate and vinyl resin represented by their copolymers, polycarbonate resin And cellulosic resins represented by cellophane, acetate, etc. It is a film consisting of a simple substance, a copolymer, a mixture, and a laminated body before the stretching and orientation treatment is completed.

The polymer having active hydrogen and a quaternary nitrogen atom in the molecule of the present invention is not particularly limited as long as it satisfies the above characteristics. It is preferably water-soluble or water-dispersible. Examples thereof include polyesters having a hydrophilic group, acrylic polymers, vinyl polymers and the like. As the active hydrogen, a hydroxyl group, an amino group, an amine group,
Examples thereof include organic acid groups. Particularly preferred is an acrylic resin into which the active hydrogen and quaternary nitrogen are easily introduced.
A hydroxyl group capable of reacting with an isocyanate group in the active hydrogen group,
There are amino groups and carboxyl groups. Examples of the acrylic monomer having a hydroxyl group include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. As the acrylic monomer having an amino group,
Examples thereof include 2-aminoethyl acrylate and 2-aminoethyl methacrylate. Examples of the acrylic monomer having a carboxyl group include acrylic acid and methacrylic acid. Examples of acrylic monomers having quaternary nitrogen include dimethylaminoethyl acrylate quaternary compounds and dimethylaminoethyl methacrylate 4
Graded product, diethylaminoethyl acrylate quaternized product,
Examples thereof include diethylaminoethyl methacrylate quaternized product, methylethylaminoethyl acrylate quaternized product, methylethylaminoethyl methacrylate quaternized product, dimethylaminostyrene quaternized product, methylethylaminostyrene quaternized product, and the like. Two or more can be used. Other polymerizable monomers include alkyl acrylates such as methyl acrylate and ethyl acrylate, methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate, vinyl monomers such as styrene, vinyltoluene and vinyl acetate. Is mentioned. The blocked isocyanate used in the present invention blocks an isocyanate group having two or more isocyanate groups in the molecule, for example, a monomeric or modified isocyanate group of tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate or the like ( It is a masked) water-soluble or water-dispersible blocked isocyanate having a cationic or nonionic property. Block components include phenols, oximes,
Those such as lactam, malonic acid ester and the like are used. This blocked isocyanate has an active isocyanate group when the block is separated by heating, and plays a role as a curing agent. The compounding ratio of the blocked isocyanate and the polymer is preferably such that the number of active hydrogen groups / the number of isocyanate groups = 0.3 to 1.4, and more preferably 0.6 to 1.1.

When a coating film is formed using the coating film forming composition of the present invention, an organic or inorganic metal salt such as a metal salt catalyst such as tin or titanium is used to accelerate the crosslinking reaction of the isocyanate compound. , And organic or inorganic alkaline compounds such as amines, polyamines, amidoamines, polyamidoamines, imidazoles, and alkali metal carbonates, or cross-linking curing agents composed of derivatives thereof are preferably used in small amounts. The solution for coating film formation in the present invention is preferably used as an aqueous solution because the polymer is water-soluble, but it may be used in combination with an organic solvent such as alcohol for the purpose of improving wettability with polyester. good. If necessary, other cross-linking agent, catalyst,
A paint or the like can be added. Further, an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, an antiblocking agent and the like may be used in combination unless the object of the present invention is impaired. Further, other binder resins may be used in combination to improve properties such as adhesiveness and blocking property. Means for mixing when mixing and laminating multi-components is not limited, and known methods such as a high-speed stirring method, a high-pressure dispersion method, and an ultrasonic dispersion method can be arbitrarily used. A method combining these methods is also suitable.

The method of laminating the solution of the composition thus obtained on the surface of the base film is not particularly limited, but a coating method of applying the solution or dispersion to the surface of the base film is particularly preferable. That is, it is preferable to apply a method of applying the composition on the surface of the substrate film, followed by drying and heat treatment. As a method of applying the coating layer on the base film, a known method can be applied. For example, spray coating method, air knife method, river coating method, kiss coating method,
Gravure coat method, Meyer bar method, roll brush method, etc. can be applied. The coating may be performed on the surface of the film after the production, or in the case of, for example, a biaxially stretched film, the coating may be performed after the film production process, that is, the cast raw fabric or the uniaxial stretching, and then the stretching treatment may be performed. The coating may be performed on the surface of the film after the production, and for example, in the case of a biaxially stretched film, it is preferable that the coating is performed after the film production process, that is, the cast raw fabric or the uniaxial stretching, and then the stretching treatment is performed. In particular, the water content of the cast film or the coating film after uniaxial stretching after coating is 20%
It is preferable to perform the stretching treatment in the above state. The coating amount of the aqueous solution of the coating film forming composition applied to the substrate film is 0.01 to 5 g / m ² as a solid content. Application amount 0.01
If it is less than g / m ² , sufficient antistatic properties cannot be obtained. 5g
Blocking becomes a problem when applied over / m ² .

By applying a corona discharge treatment to the base film before applying the solution of the above composition, the coatability of the solution is improved, or the adhesion between the base film and the coating film is improved. The means of can be adopted. The wettability and adhesiveness of the film surface can be improved by subjecting the coating layer after lamination to corona discharge treatment, corona discharge treatment in a nitrogen atmosphere, ultraviolet irradiation treatment and the like.

The laminated film produced by the above method is particularly useful as a base material for magnetic recording media such as video tapes, audio tapes, computer tapes and floppy disks. It is also useful as a substrate for general industrial films such as membranes, telephone cards, labels, microfilms, diazo films, OHP films and the like.

[0011]

EXAMPLES Next, examples and comparative examples of the present invention will be shown. The evaluation methods used in the present invention are shown below. 1) Surface resistance Takeda Riken Co., Ltd. specific resistance measuring device applied voltage 500V, 2
It was measured under the conditions of 3 ° C. and 20% RH. 2) Evaluation of water resistance and solvent resistance The film was immersed in each solvent, and the surface resistance was measured after standing at room temperature (26 ° C) for 16 hours.

[0012]

Example 1 Methyl methacrylate / ethyi by a conventional method
Acrylate / 2-hydroxyethyl methacrylate
/ Dimethylaminoethyl methacrylate quaternary
Copolymerized at a ratio of 47/21/7/25
To obtain an aqueous copolymer solution. To this copolymer aqueous solution,
Elastron MF9 as a isocyanate compound
(Daiichi Kogyo Co., Ltd., nonionic) solid content of the copolymer
15% by weight with respect to
at64 (manufactured by Daiichi Kogyo Co., Ltd.) is the block isocyanate
Add 5.0% by weight to the nate and mix to obtain a solid content of 7%
% To obtain an aqueous solution of the coating film forming composition. Intrinsic viscosity 0.65
Melt polyethylene terephthalate at 280-300 ℃
Melt extrude and cool with a 15 ° C chill roll to cool the unstretched film.
Film, and the unstretched film at 85 ° C
After stretching 3.5 times in the machine direction between the pair of rolls,
10 g of an aqueous solution of the coating film forming composition prepared by the kiss coating method
/ M ²Apply, dry with hot air at 70 ℃, then tenter
At a temperature of 98 ° C. for 3.5 times in the transverse direction, and then 200 to 2
Biaxially stretched coating with 100 μm thickness heat set at 10 ° C
A polyester film was obtained. Characteristics of the obtained film
The sex is shown in Table 2.

[0013]

Examples 2 to 5 The same procedure as in Example 1 was repeated except that the composition of the coating film forming composition was changed as shown in Table 1.

Examples 6 to 9 The same procedure was carried out except that the base film and the coating film forming composition of Example 1 were changed as shown in Table 1 and the stretching and heat setting conditions were changed appropriately.

[0014]

Comparative Examples 1 to 5 The same procedure as in Example 1 was repeated except that the composition of the coating film forming composition was changed as shown in Table 1.

Comparative Example 6 A commercially available anionic antistatic agent consisting of the resin (A) of Comparative Example 2 in Table 1 and sodium sulfonate was used.
The same procedure as in Example 1 was carried out except that the mixed solution was used as the coating solution at a ratio of / 2.

[0015]

Comparative Example 7 The same procedure was carried out except that the aqueous solution of the coating film forming composition of Example 1 was not applied. As shown in Table 2, the antistatic films of the examples have small surface resistance even at low humidity, excellent antistatic properties, and excellent water resistance and solvent resistance. On the other hand, in Comparative Example 1, the spreadability of the coating film is poor, a uniform coating film cannot be formed, and antistatic properties cannot be imparted. Comparative Examples 2 and 3 are inferior in antistatic property. Comparative Example 4 is excellent in antistatic property but inferior in water resistance and solvent resistance. Comparative Example 5 cannot be applied because the aqueous solution of the composition to be applied aggregates. Comparative Example 6 is inferior in antistatic property at low humidity. Comparative Example 7 has no antistatic property.

[0016]

As described above, since the antistatic film of the present invention is excellent in antistatic property at low humidity, and also excellent in water resistance and solvent resistance, it is used as a base material for magnetic recording media and for general industrial use. It can be widely and suitably used for films and various packaging films.

[0017]

[Table 1]

[0018]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koji Yamada 2-1-1 Katata, Otsu-shi, Shiga Toyobo Co., Ltd. (72) Inventor Muyuki Kawaguchi 2-1-1 Katata, Otsu, Shiga No. Toyobo Co., Ltd. Research Institute (72) Inventor Toshitake Suzuki 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. Research Institute

Claims (1)

[Claims] 1. A composition comprising at least one surface of a thermoplastic resin film coated with a polymer containing active hydrogen and a quaternary nitrogen atom in the molecule and at least one polyfunctional blocked isocyanate compound. And laminated film.