JPH0517606A - Undercoated film to be coated with aqueous coating - Google Patents

Abstract

PURPOSE:To provide an undercoated polyolefin, polyester, or polystyrene film which can be easily topcoated to give a coated film having a newly imparted function on the coated surface, showing greatly improved adhesion strength after drying, and free from the fear of quality deterioration such as turning opaque or turbid by improving the composition of an undercoat to be used for forming an undercoat layer. CONSTITUTION:A coating liquid comprising a mixture of a binder solution and a colloidal solution prepared by dispersing ultrafine particles of silicic anhydride into water or a solvent, is applied on a polyolefin, polyester, or polystyrene film and dried to thereby form an undercoat layer.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Synthetic paper, wallpaper, adhesive / tape tape, photographic film, and various industrial materials are manufactured by a coating method using a water-based coating liquid on the surface of a polyolefin, polyester, or polystyrene film. At this time, a coated film having a water-based undercoat layer on the surface of the base film, which has good wetting between the base film and the water-based coating liquid and also has good adhesive strength after drying. It is about.

[0002]

2. Description of the Related Art In the case of imparting various properties to the film surface by a surface coating method, if a composition that gives a characteristic property to the coating liquid is applied, it will adhere when directly applied to a polyolefin, polyester or polystyrene film. Often insufficient strength.

Therefore, it is conceivable that a binder liquid is selected and applied as the pretreatment, and then the surface layer is applied thereon.
Even in this case, especially when an aqueous surface layer coating solution is used, sufficient adhesive strength cannot be obtained.

On the other hand, when an undercoat layer is formed by mixing a powdery filler with a binder solution and coating it on a base film, the adhesive strength is improved. It is considered that this is because the undercoat layer is roughened, but the adhesive strength is not sufficient, and the undercoat layer itself often becomes brittle.
In addition, since it is devitrified, it may impair the aesthetics.

In general, when the powder filler as described above is used, the coating layer is likely to be opaque, which is likely to be an obstacle to applications in which a transparent or bright color is expected.

[0006]

Therefore, the problem to be solved by the present invention is to provide a new function on the surface of a polyolefin or polyester or polystyrene film by using an aqueous coating liquid which has advantages in handleability and safety. In the case of imparting
By forming a coating layer, the undercoat can be easily coated, the adhesive strength after drying can be greatly improved, and there is no risk of deterioration of quality such as opacity and color turbidity. -To provide a coated film provided with a coating layer.

[0007]

The present invention has been made for the purpose of solving the above-mentioned problems, and its constitution is a polyolefin or polyester or polystyrene film, a binder solution and ultrafine particles of silicic anhydride in water or It is characterized in that an undercoat layer is provided by coating and drying a coating liquid comprising a mixture of colloidal solutions dispersed in a solvent.

Thus, in the present invention, the polyolefin, polyester or polystyrene film which can be used as the substrate is a transparent film or a filler such as titanium oxide.
Those that are made semi-transparent or opaque, have a foamed structure, and have a twisting property for special purposes (when wrapping a candy, etc., if you add a twist, the shape will remain as it is)
There are those such as hand-cutting properties (the property of tearing by hand like paper) and the like, but especially when a transparent film is used, the feature of the present invention that a transparent coat can be formed can be utilized. .

As the binder solution of the undercoat component, an aqueous solution of polyacrylic acid type, polymethacrylic acid type, polyurethane, vinyl chloride vinyl acetate copolymer type or the like can be used for polyolefin or polystyrene film. It is preferable to use a cross-linking agent such as isocyanate, and it is particularly preferable to use a room temperature cross-linkable acrylic water-based emulsion that utilizes a cross-linking reaction between a hydrazine residue and carbonyl. In addition to the above, particularly for polyester films, those containing water-based saturated copolymerized polyester or vinylidene chloride as the main component exhibit excellent adhesive strength.

Although it is possible to use a solvent-based binder liquid, in the present invention, which can exert a particularly improving effect when the overcoat liquid is an aqueous liquid, it is not necessary to consider the safety of the equipment. In practice, it is preferable to use a water-based binder, for example, to make it possible to share the equipment with the overcoat liquid.

On the other hand, as the colloidal solution of silicic acid anhydride, those having a particle size of 5 to 50 nm (nanometer) are excellent in transparency, but those having a particle size of 100 nm or more can also exert the effect depending on the use. .

The coating liquid for undercoating requires the combination of the binder and the silicic acid anhydride colloidal liquid, but in addition to the above, a thickener, a leveling agent, which is usually used for improving the coating liquid,
Wetting agents, antistatic agents, etc. can be added.

The coating is a gravure roll coater,
Although a reverse roll coater or the like can be used and is not particularly limited, the above coating liquid does not increase in viscosity in spite of the addition of an inorganic substance, so that it is an air knife coater having a high solid content.
There is also an advantage that

The coating liquid applied as the surface layer is formed for the purpose of imparting various functions to the product. The functions include various printing papers, printing papers, wallpapers, adhesive / adhesive tapes.
It can be applied to a wide range of applications such as packaging, packaging materials, and photographic films. As for the ratio of the binder liquid and the colloidal silica in the coating liquid for undercoat, the colloidal silica needs to be added in an amount of 5 PHR or more, preferably 10 PHR or more in terms of solid content with respect to the binder liquid. Even if the amount is less than this, some improvement effect is recognized, but the effect of the present invention becomes remarkable by such a large amount addition. However, when the amount of colloidal silica exceeds 150 PHR with respect to the amount of binder liquid, not only the undercoat layer becomes brittle in some cases, but also after the overcoat liquid is applied and dried to form the overcoat layer. , It may hinder the adhesion to the overcoat layer. A thickness of the undercoat layer of 10 μm or less is sufficient, but from the viewpoint of economy and cracking, it is 1 to 7
μm is preferred.

[0015]

The present invention is as described above. By adding colloidal silica to the binder solution, not only the adhesion of the undercoat layer to the base film is improved, but also The adhesiveness with the coating layer is greatly improved. Although its effect is not clear, the addition of colloidal silica lowers the electric resistance of the surface of the undercoat layer and also improves the water wettability, so that a silanol group appears on the surface and this It is considered to contribute to adhesion.

Example 1 100 parts of acrylic binder (Acronal YJ2721D manufactured by Mitsubishi Petrochemical Vardeche) 100 parts colloidal silica (Snowtex C manufactured by Nissan Chemical Co., Ltd.) 30 parts undercoat coating liquid Was coated on a polypropylene film having a thickness of 50 μm with a wire bar coater of 0.2 mm and dried. A vinyl acetate-based adhesive (3500 for Polysol bonding manufactured by Showa High Polymer Co., Ltd.) was coated on this product with a wire bar of 0.5 mm, and HATRON paper was stuck on it. After drying, the hatron paper was peeled off, but the adhesion was strong and the polypropylene film was broken.

Comparative Example 1 In Example 1, a similar test was conducted using only the acrylic binder as the undercoat liquid, but it was easily peeled off between the acrylic binder and the vinyl acetate adhesive.

Comparative Example 2 The amount of colloidal silica in Example 1 was 200 parts,
A similar test was conducted, but it was easily peeled off between the acrylic binder and the vinyl acetate adhesive.

Example 2 As a binder solution, 20 parts of colloidal silica (SNO-TEX XBA-ST manufactured by Nissan Chemical Industries, Ltd.) was added to a solution consisting of 30 parts of chlorinated polyethylene resin and 70 parts of toluene. When tested, good adhesion results were obtained.

Comparative Example 3 A similar test was conducted by adding 5 parts of powdered silica (Mizucasil P-526 manufactured by Mizusawa Chemical Co., Ltd.) to 100 parts of the binder solution of Example 2 and the same effect was confirmed by the addition of powdered silica. But,
It peeled off more easily than in Example 2.

Example 3 An underlayer consisting of 20 parts of an acrylic emulsion (Jurima ET-410 manufactured by Nippon Pure Chemical Co., Ltd.) as a binder liquid and 10 parts of colloidal silica (Snowtex N manufactured by Nissan Chemical Co., Ltd.)
The same test as in Example 1 was conducted using the coating solution.
The peel test resulted in damage to the paper and undercoat layers.

Example 4 A thick polyethylene terephthalate film was coated with 100 parts of a saturated copolyester binder (Vylonal MD1200 manufactured by Toyobo Co., Ltd.) and colloidal silica (manufactured by Nissan Kagaku Co., Ltd.).
30 parts of SNO-TEX C) was added, coated and dried. A polyurethane emulsion was coated on this and dried. This product was transparent, and when it was subjected to resin-based thermal transfer, it exhibited excellent abrasion resistance.

EXAMPLE 5 Acrylic Binder (Mitsubishi Yoka Verdish Co., Ltd. Acronal YJ2721D) 100 parts Colloidal silica (Nissan Chemical Co., Ltd. SNO-TEX 20L) 30 parts Wetting agent (San Nopco SN Wet 366) 1 part undercoat coating liquid 0.2 mm wire bar
Then, apply it to a transparent polystyrene film with a thickness of 50 μm,
A transparent film was obtained after drying. This product was coated with a silver halide sensitizer emulsion, dried, and then exposed to an image for development, and exhibited excellent OHP suitability in both color development and transparency.

Example 6 Vinylidene chloride-based binder 100 parts (Kureha Chemical Industry Co., Ltd., Kureharon latex DO-818) Colloidal silica (Nissan Chemical Co., Ltd., SNO-TEX C) 50 parts undercoat coating liquid 0.2mm wire bar
Then, it was coated on a transparent polyethylene terephthalate film having a thickness of 50 μm and dried to obtain a transparent film. A silver halide sensitizer emulsion was applied to this product and dried, and then a tape was applied and peeled off. As a result, the adhesion was strong and the silver halide sensitizer emulsion was not peeled off. A similar peeling test was conducted after the image was exposed and developed, but the adhesion was strong and the silver halide sensitizer emulsion was not peeled off.

Comparative Example 4 In Example 6, a similar test was conducted by using only the vinylidene chloride binder as the undercoat liquid, but a simple test was conducted between the vinylidene chloride binder and the silver halide sensitizer emulsion. It peeled off.

Claims (4)

[Claims] 1. A coating liquid comprising a mixture of a binder liquid and a colloidal solution in which ultrafine particles of silicic acid anhydride are dispersed in water or a solvent is applied to a polyolefin or polyester or polystyrene film and dried to obtain an undercoat. -A coated film having an undercoat layer for water-based coating, characterized in that a coating layer is provided. 2. A room temperature crosslinkable aqueous emulsion, wherein the binder liquid comprises (A) a hydrazine derivative having at least two hydrazine residues, and (B) an aqueous dispersion of a carbonyl group-containing acrylic copolymer. The coated film according to claim 1, wherein the used coating agent is a main component. 3. The coated film according to claim 1, wherein the binder liquid contains a saturated copolyester as a main component. 4. The coated film according to claim 1, wherein the binder liquid contains vinylidene chloride as a main component.