JPS61151539A - Photohardenable composition for protective cover of photograph - Google Patents

Abstract

PURPOSE:To protect a photograph from stains, deterioration in quality, deforma tion, scratches, abrasion, etc., and to enable it to be written on with a pencil, etc., by incorporating an inorg. and/or org. light-transmitting fine powder in a photohardenable resin compsn. CONSTITUTION:The photohardenable resin compsn. contains the inorg. and/or org. light-transmitting fine powder in an amt. of 0.5-75wt%, and when it is contained <0.5wt%, the protective film is too smooth to be written on with a pencil or the like, and when >75wt%, it can be easily written on with a pencil or the like, but the coat film is too hard, and becomes liable to crack and worse in transparency. Since the protective film is cross-linked by irradia tion with UV rays, it is enhanced in scratch resistance, as well as resistances to water, solvents, and chemicals, and various stains can be easily wiped off.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photocurable composition for protective coating of photographs, and more specifically, to prevent staining of the image surface of photographs (7. The present invention relates to a photocurable composition that prevents an image layer from deteriorating and deforming, or from being scratched or scratched, and at the same time allows writing on a protective coating with a writing instrument such as a pencil.

[Conventional technology]

BACKGROUND ART Conventionally, in order to prevent stains, scratches, abrasions, etc. from forming on the surface of a photograph, methods have been proposed or practiced in which the surface of the photograph is coated with a photocurable resin composition. For example, (a) A method of coating with an acrylic-urethane photocurable resin composition (US Pat. No. 40921'23!-)
.

(b) A method of coating with a photocurable resin composition comprising an acrylic-urethane resin and a siloxy-containing polycarbinol (US Pat. No. 4,333,998).

(c) A method of coating with a photocurable resin composition containing a polymerizable epoxy compound, a polymerizable acrylic compound, and a polymerizable organofunctional silane as film-forming components (Published Patent No. 1983-
501642).

etc. are known.

[Problem that the invention seeks to solve]

The above-mentioned conventional method has the advantage of being able to form a film with excellent protection properties such as stain resistance, deterioration and deformation resistance, scratch resistance, and abrasion resistance on the surface of the photograph. On the other hand, the protective film formed here is a hydrophobic smooth surface, so even if you try to write letters, symbols, figures, etc. on the film with a pencil, the pencil's glue will scrape and the writing will be difficult. The disadvantage is that it cannot be done at all. This drawback is not limited to pencils, but also occurs in writing instruments such as ballpoint pens and felt-tip pens that use water-based ink, as the water-based ink repels and makes it impossible to write clearly.

In reality, cases where it is necessary to write on the protective film of a photograph with a pencil or the like are, for example, writing or filling in various data on aerial photographs, recording shooting records on other photographs, and writing text on postcards. However, the conventional protective coatings described above are not yet able to meet these requirements.

Therefore, it is an object of the present invention to provide a composition that can protect photographs from stains, deterioration, deformation, scratches, abrasions, etc., and at the same time form a protective coating that can be written on with a pencil or the like.

[Means to solve the problem]

To achieve the above object, the present invention provides (a) a photocurable resin composition, and (b) an inorganic and/or organic photocurable composition for protective coating of photographs.

[For production]

Since the composition of the present invention contains a specific amount of the light-transmitting fine powder (b), it is possible to form a protective film with minute irregularities and improved hydrophobicity on the surface of the photograph. This makes it possible to write with a pencil or the like. Note that the term "pencils, etc." as used in the present invention includes not only ordinary pencils, but also colored pencils, water-based ink-based ballpoint pens, felt-tip pens, and the like.

Photocurable resin composition (a) that can be used in the present invention
) is not particularly limited, and any conventionally known ones can be used. Examples include photocurable prepolymers (e.g., polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate, oligoacrylate, (alkyd acrylate, polyol acrylate, polyphrydien acrylate, etc.), photopolymerizable monomer that can be added as necessary<fc, for example, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 1.3
-Butanediol diacrylate, 1,4-butanediol diacrylate, ethylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, trimethylol proton triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di acrylic esters such as pentaerythritol hexaacrylate, or methacrylic esters thereof) and a photopolymerization initiator (for example, compounds such as acetophenone, benzophenone, Michler's ketone, benzyl, benzoin, or derivatives thereof) The light-transmitting fine powder (1)) that can be used in the present invention must have a light transmittance that does not hide the photographic image when it is dispersed in a protective film and covers the photographic surface. Examples of such powders include inorganic materials such as silicon oxide, ALSMf, modified silicon oxide whose surface has been treated with organic materials, talc,
Extender pigments such as barium sulfate, calcium carbonate, diatomaceous earth, alumina white, and kaolin, inorganic light-transmitting fine powders such as spherical, flaky, or irregularly shaped glass powders, and polyethylene resins, polypropylene resins, vinyl chloride resins, It is an organic light-transmitting fine powder made of acrylic resin, fluororesin, polycarbonate resin, etc., and crosslinked products thereof.

The particle size of the light-transmitting fine powder (b) is not particularly limited, but if the particle size is too small, it will be completely buried in the protective coating, forming a smooth surface, making it impossible to write on it with a pencil or the like. Furthermore, if the particle size is too large, the surface of the protective coating will become extremely uneven, causing pencils and the like to get caught during writing, making it impossible to write smoothly, and also deteriorating the appearance (commercial value). The preferred particle size in the present invention is:
01-200μm1 Particularly preferred particle size is 0.5-50
It is μm.

The photocurable resin composition (a) in the present invention is light transmitting, and when the content of (b) is less than 0.5% by weight, when it is more than 0.5%, writing with a pencil etc. is good, but the coating film becomes hard, tends to crack, and causes drawbacks such as decreased transparency. The preferred content of (b) for the present invention is 1 to A%, particularly preferably 3 to ge!% when (b) is an inorganic fine powder. -% by weight, when (b) is an organic fine powder, it is 1 to % by weight.

Various additives can be further added to the composition of the present invention having the above structure. For example, in the composition, 1
0% by weight or less of ultraviolet absorbers (for example, Ciba, Geigy Tinuvin 328, Tinuvin 9001, Tinuvin 3)
26, Chikubin 32 Fuchinupin P1 Sanol LS292
, Sanol LS144, etc.) is preferable because it has a particularly excellent effect of preventing discoloration and fading on photographs. Also,
Plasticizers, antifoaming agents, surfactants, coloring pigments, dyes, and other various additives commonly used in the field of coatings can be conventionally included to the extent that they do not impair transparency.

Since the composition of the present invention is generally supplied in liquid form, it can be applied as it is to various coating means for forming a film.
It is preferable to adjust the coating viscosity to an appropriate level using an appropriate organic solvent to suit each coating method. Examples of organic solvents that can be used are benzene, toluene, xylene, mineral spirit cyclohexane, tetrahydro7rane, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, acetone, methyl ethyl ketone,
Such as cyclohexanone.

Formation of a film using the composition of the present invention can be carried out using a coating method known per se, such as spray coating, dip coating, roll coating,
This can be done using gravure coating, flow coating, barcode coating, doctor blade coating, air knife coating, etc. There is no limit to the thickness of the coating, but if it is too thick, the clarity of the photographic image may be impaired, so
0 μm is preferred, and 0.5 to 100 μm is particularly preferred.

The composition of the present invention coated onto a photographic surface is easily cured in a short period of time by ultraviolet light irradiated from a xenon lamp, a low-pressure, medium-pressure or high-pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a tungsten lamp, etc. be able to.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

The composition of each component in the examples is expressed in parts by weight.

Example 1 A photocurable composition was prepared by stirring and mixing each component in the following blending ratio using a stirrer.

Urethane acrylic prepolymer 60 parts (Unidic #17-849 manufactured by Dainippon Ink & Chemicals) Pentaerythritol tri- and tetra 30 parts Acrylate (mixture) Benzoin ethyl ether 5 parts 2-
Ethylhexyl acrylate 5 parts Silicon oxide powder (manufactured by Mizusawa Chemical Co., Ltd., Mizukasil 30 parts P-526
(Particle size: 5 μm, 95% pass) The photocurable composition prepared above was applied to the image surface of a color photograph so that the cured film thickness was approximately 4 μm.
It was coated using a roll coater and heated at 80W/
CRN output UV lamp under 5 countries, 8rr
It was passed through at L/ship speed and cured. On the cured film, apply a pencil (
When letters, figures, etc. were written on the paper with a hardness of F) and water-based signboard, there was no breakage, blurring, or repelling of the handwriting, and the writing property was extremely good. Although water was dropped onto the cured film, it was easily wiped off and no abnormality was observed in the photograph, indicating good protection. Furthermore, the surface of the cured film was cleaned using a nylon scrubber (Sumitomo 3M Co., Ltd., Scotch Brite), and
The surface was rubbed 10 times at a pressure of '/25 Ca to examine the occurrence of scratches on the surface, but no scratches were observed on the cured film, indicating good scratch resistance.Example 2゜Tetramethylolmethanethria 40 parts Acrylate monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., NK-Ester A-TMM-3L) Urethane acrylate prepo 50 parts Li-(manufactured by Inu Nippon Ink Chemical Co., Ltd., Unidic V-4402) Photoinitiator (manufactured by Ciba Geigy Co., Ltd.) , 5 parts Irgacure 8184) Ultraviolet absorber (manufactured by Shiraishi Kogyo Co., Ltd., 3 parts G-Sorb #201) Polyethylene resin powder (particle size 10 parts 20 μm19
5% pass) A photocurable composition with the above blending ratio was prepared in the same manner as in Example 1↓
The surface of the photograph was coated using a gravure coater so that the thickness of the cured film was about 100 μm, and then cured in the same manner as in Example 1. When the writability with a pencil was examined, it was found that it was good. It had writability.

Comparative Example 1゜A photocurable composition was prepared in the same manner as in Example 1 except that the silicon oxide powder was removed from the composition of Example 1, and the coating thickness after curing was approximately 30 μm using a bar coater. The surface of the photograph was coated as shown. The obtained cured film is smooth and
The water resistance and scratch resistance tested in the same manner as in Example 1 were excellent, but writing with a pencil was not possible at all.

〔Effect of the invention〕

Since the composition of the present invention contains a specific amount of light-transmitting fine powder, it is possible to form a protective film on the surface of a photograph that can be written on with a writing instrument using a pencil or water-based ink. The film is cross-linked by ultraviolet irradiation, so it has excellent scratch resistance, water resistance, solvent resistance, and chemical resistance, and various types of stains can be easily wiped off, leaving the film in its original state. It is a composition with extremely excellent properties, such as being able to preserve images for a long period of time, and has high utility value.

Claims (1)

[Claims] (1) Consists of a composition of (a) a photocurable resin composition and (b) an inorganic and/or organic light-transmitting fine powder, and the content of the light-transmitting fine powder (b) in the composition. is 0.5
75% by weight of a photocurable composition for protective coating of photographs.