JPH089664B2 - Method for manufacturing coated film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a coated film used in the field of magnetic recording or thermal transfer recording.

2. Description of the Related Art In the field of magnetic recording or thermal transfer recording, an anchor coat layer is generally provided in order to improve the adhesive strength between the substrate and the magnetic recording layer or between the substrate and the thermal transfer color material layer. In the case of heat-sensitive transfer recording, a polyethylene terephthalate film base material is provided with a slip heat-resistant layer so that the polyethylene terephthalate film base material stably runs on the thermal head. It is known that when a reactive resin is used for the anchor coat layer or the slip heat resistant layer and fine particles are contained, the adhesive strength and the running stability (dropout) are further improved.

Conventionally, as a method for mixing and dispersing a reactive resin and fine particles,
A method of dispersing with an attritor using alumina balls, a method of dispersing with a three-roll mill, and the like are known.

Problems to be Solved by the Invention In order to further improve the adhesive strength, the smaller the particles, the higher the strength, and the smaller the particles, the better the running stability. Especially when the primary particle size or average particle size of the fine particles is 0.2 μm or less, it becomes more difficult to uniformly disperse the fine particles in the reactive resin. When applied, unevenness of fine particles occurs in the coating film.

In addition, since reactive resins generally have a high viscosity, it is necessary to reduce the viscosity by using a coating composition containing a solvent in order to coat a thin film coating of about 1 μm in a state of uniform particle dispersion. is necessary. The triple roll mill cannot be applied to such low viscosity paints.

It is an object of the present invention to obtain a method for producing a coated film which can form a cured thin film in which fine particles are uniformly dispersed by using a reactive resin having a low viscosity to a high viscosity or a solid range.

Means for Solving the Problems A reciprocating pump having a primary particle diameter or an average particle diameter of 0.2 μm or less and at least one kind of fine particles selected from inorganic fine particles or carbon black, a reactive resin and a solvent. And a coating composition consisting of a reaction initiator and an emulsified product using an emulsifier that generates a shock wave by a narrow groove channel plug is coated on a substrate, and the thickness after solvent drying on the substrate. A cured coating film having a size of 10 μm or less is formed.

Since a working solvent is used, viscosity of about 10,000 poises (25 ° C) or higher or solid reactive resins can be reduced.
Further, this reduction in viscosity can facilitate the dispersion of fine particles. 0.2μm into highly viscous liquid such as reactive resin
Dispersion of the following ultrafine particles can also be achieved by reducing the viscosity with an emulsifying machine that generates a shock wave and a solvent. Further, since it can be highly dispersed, it is easy to obtain a coating composition capable of forming a uniform thin film. Further, since the solvent is used during the emulsification, the heat generated during the emulsification is small, and the reaction is unlikely to proceed even when the reaction initiator is contained.

Example The coating composition in the present invention comprises at least a reactive resin, a reaction initiator, fine particles and a solvent.

The reactive resin is a resin that forms a cured product by adding various reaction initiators (for example, various curing agents, sensitizers, reaction auxiliaries, etc.) or further by heat, particle beam, or the like.

Examples of the reactive resin include unsaturated polyester resin, saturated copolyester resin, epoxy resin, melamine resin, alkyd resin, phenol resin, furan resin, acrylic monomer, acrylic oligomer, guanamine resin, diallyl phthalate resin, urethane resin, polyvinyl resin. Butyral resin and the like.

Particularly when the reactive resin is a radical polymerization type or ionic polymerization type or a resin having active hydrogen, good results are obtained.

Further, when the reactive resin is an ultraviolet curable resin, it has a long pot life and is easy to use.

Examples of the UV-curable resin include various acrylate resins, specifically, polyester acrylate, epoxy acrylate, urethane acrylate, silicone acrylate, polyol acrylate, polyacetal acrylate, and the like, and reactive diluents such as tetrahydrofurfuryl acrylate. It can also be diluted and used. A mixed resin of polyene and polythiol can also be used.

Further, an ultraviolet curable epoxy resin can also be favorably used. For example, there is an alicyclic epoxy resin or the like.

The reaction initiator is a compound for initiating or accelerating the curing reaction of the reactive resin, and is generally called a curing agent, a sensitizer or the like.

Examples of the curing agent include amine compounds, isocyanate compounds, epoxy compounds, melamine compounds, phenol compounds, peroxides, diazonium salts, iodonium salts and sulfonium salts.

Examples of the sensitizer include benzophenone, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone and the like.

The fine particles are particles having a primary particle diameter or average particle diameter of 0.2 μm or less.

For example, synthetic amorphous silica, carbon black, alumina, titanium oxide, calcium silicate, aluminum silicate, calcium carbonate and the like can be favorably used.

Synthetic amorphous silica includes anhydrous silica and hydrous silica. Ultrafine particles produced by a vapor phase method are particularly useful as anhydrous silica. For example, there is ultrafine particulate silica developed by Degussa, West Germany. Similarly, aluminum oxide, titanium oxide (both of which are manufactured by Nippon Aerosil Co., Ltd.) and the like obtained by the vapor phase method are also particularly useful.

Examples of hydrous silica or white carbon include Shionogi Pharmaceutical Co., Ltd. “Carplex”, Nippon Silica Industry Co., Ltd. “Nipseal”, Mizusawa Chemical Co., Ltd. “Shilton”, Tokuyama Soda Co., Ltd. “Fineseal,”
It is commercially available under the name "Tokushiru".

The solvent is an organic solvent and is not particularly limited.
The coating composition may contain various additives in addition to the reactive resin, the reaction initiator, the fine particles and the solvent.

For example, various surfactants, especially silicone-based surfactants and fluorine-based surfactants are preferable.

Further, various lubricants (especially various silicone oils, waxes, etc.), thermoplastic polymers and the like may be contained.

The emulsifier is a device that generates a shock wave by a reciprocating pump and a narrow groove flow path plug as a basic configuration. For example, there is the ALM2 machine manufactured by Pierre Guerlain (France).

The emulsification of the coating composition is performed in a coating composition composed of at least a reactive resin, a reaction initiator, fine particles, and a solvent, at least the reactive resin, the fine particles, and the solvent are shock-waved by a reciprocating pump and a narrow channel plug. The emulsification is performed using an emulsifying machine that generates

After emulsifying the reactive resin, the fine particles and the solvent, a reaction initiator is added to produce a coating composition. Also, a reaction initiator may be added from the beginning for emulsification treatment. Also, from the beginning, various additives such as a surfactant may be added for emulsification treatment. Alternatively, a part of the solvent may be used for the first emulsification with the reactive resin and the rest of the solvent may be added to the emulsified liquid after the emulsification treatment.

From the coating composition produced according to the present invention, a particularly thin cured thin film, generally a coating film having a thickness of 10 μm or less, particularly about 1 μm, can be uniformly obtained.

 Specific examples will be shown below.

(Example 1) After dissolving 10 parts by weight of an epoxy acrylate resin (bisphenol type, viscosity of about 10,000 poise: 25 ° C) in 90 parts by weight of ethyl acetate, ultrafine particle hydrophobized silica (R972, primary particle size:
About 16 mμ, Nippon Aerosil Co., Ltd.) 6 parts by weight were added and well stirred with a glass rod, and silica was well dispersed by an emulsifier (ALM2 type). 2-in this dispersion as a sensitizer
0.5 parts by weight of hydroxy-2-methylpropiophenone was added and mixed well with a glass rod. It was found that even if this coating composition was left to stand for a whole day and night, no precipitation of particles occurred and a uniform dispersion liquid was obtained.

This coating composition was applied to one side of a polyethylene terephthalate film having a thickness of 9 μm by a wire bar method, dried with hot air at 100 ° C., and then cured by irradiation with a high pressure mercury lamp of 160 W / cm. By the above process, 100 m continuous coating was carried out to obtain a coated film having a cured coating film thickness of 0.8 μ. This coating film was a white coating film in which the ultrafine particles were uniform on the entire surface by visual observation over a length of 100 m. A color material layer consisting of a sublimable dye and a binder was provided on this coating film, and a polyimide film substrate with good smoothness in image quality was used even when heat-transferred onto an image receiving paper (recording paper) with a thermal head. Exactly the same as the case, showing that the dispersibility of the particles is very good.

Example 2 30 parts by weight of an epoxy resin (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, viscosity about 350 centipoise 25 ° C.) was dissolved in 100 parts by weight of ethyl acetate, and then carbon black (1 Secondary particle size 20m
μ, Conductex SC, Colombian Carbon Japan Co., Ltd.) After adding 6 parts by weight and stirring well with a glass rod,
Carbon black was well dispersed by an emulsifying machine (ALM2 type). 1.5 parts by weight of a curing agent (pp-33, Asahi Denka Kogyo Co., Ltd.), a surfactant (L-7500, Nippon Unicar Co., Ltd.), 1.5 parts by weight, dimethyl silicone oil 0.15
Parts by weight were added and well stirred with a glass rod. Thereafter, a coated film having a cured coating film thickness of 2.1 μm and a coating length of 100 m was obtained in the same manner as in the examples. This coating film was a light black coating film in which carbon black was uniformly distributed over the entire surface by visual observation over a length of 100 m.

EFFECTS OF THE INVENTION The present invention has a primary particle size or an average particle size of
At least one type of fine particles having a particle size of 0.2 μm or less, selected from inorganic fine particles or carbon black, a reactive resin, and a solvent are emulsified using a reciprocating pump and a narrow groove plug to generate a shock wave. By a coating composition comprising a coating composition and a reaction initiator on a substrate and forming a cured coating film having a thickness after solvent drying of 10 μm or less on the substrate, By using a reactive resin ranging from low viscosity to high viscosity or solid, a cured thin film in which fine particles having a coating film thickness of 10 μm or less are uniformly dispersed can be formed on a substrate.

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Claims (8)

[Claims] 1. The size of the primary particle diameter or the average particle diameter is
At least one type of fine particles having a particle size of 0.2 μm or less, selected from inorganic fine particles or carbon black, a reactive resin, and a solvent are emulsified using a reciprocating pump and a narrow groove plug to generate a shock wave. A method for producing a coating film, which comprises coating a coating composition comprising a coating composition and a reaction initiator on a substrate, and forming a cured coating film having a thickness after solvent drying of 10 μm or less on the substrate. 2. The method for producing a coating film according to claim 1, wherein the coating film is coated with the coating composition and then the coating film is cured by heat, light or an electron beam. 3. The method for producing a coating film according to claim 1, wherein the reactive resin is a radical polymerization type reactive resin. 4. The method for producing a coating film according to claim 1, wherein the reactive resin is an ionic polymerization type reactive resin. 5. The method for producing a coating film according to claim 1, wherein the reactive resin is a resin having active hydrogen. 6. The method for producing a coating film according to claim 1, wherein the reactive resin is a light or electron beam curable resin. 7. The method for producing a coating film according to claim 1, wherein the reactive resin is an acrylic resin or an alicyclic epoxy resin. 8. The method for producing a coating film according to claim 1, wherein the fine particles are ultrafine particles produced by a vapor phase method.