JPH0462048A - Opaque sheet - Google Patents

Abstract

PURPOSE:To make it possible to obtain film for the aperture stop of a camera, the manufacture of which is easy and the characteristics of which are excellent, by a method wherein synthetic resin layer, which possesses surface matting properties, electrical conductivity and opacity together, is laminated onto one side or both sides of base plastic film. CONSTITUTION:Polyester film is preferable as base plastic film 1 from the view point of heat resistance, cost, rigidity and the like. Synthetic resin layer 2 to be laminated to the film 1 is preferably made of thermosetting resin or ionizing radiation curable resin. Further, surface matting properties are preferably given to said synthetic resin layer 2 by adding matting agent. Furthermore, electrical conductivity and opacity are preferably given to the synthetic resin layer to be laminated by adding carbon black. In addition, these synthetic resin layers are laminated onto the base plastic film by coating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a light-shielding sheet suitable for manufacturing members such as aperture film for photographic cameras or video cameras.

[Conventional technology]

2. Description of the Related Art Conventionally, a light-shielding film (sheet) has been used in a diaphragm section of a photographic camera or a video camera. The sheet is usually made by kneading carbon black into PET (polyethylene terephthalate), forming it into a black sheet, applying sand matting to both sides, and further dyeing to increase the density if necessary. is used.

[Problem to be solved by the invention]

The conventional light-shielding film for the aperture section of a camera described above is expensive because the manufacturing process is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems in the prior art and provide a film for a camera aperture section that is easy to manufacture and has excellent characteristics.

[Means to solve the problem]

In order to achieve the above object, the inventors of the present invention have conducted extensive research, and have discovered that a plastic film laminated with a synthetic resin layer that has not only light-shielding properties but also matte properties and conductivity has been developed.
It was discovered that the film is suitable as a light-shielding film for the aperture section of a camera, and the present invention was completed.

That is, the present invention is a light-shielding sheet characterized in that a synthetic resin layer having surface matte properties, conductivity, and light-shielding properties is laminated on one or both sides of a base plastic film.

In the light-shielding film of the present invention, the synthetic resin layer to be laminated is preferably made of a thermosetting resin or an ionizing radiation-curable resin. Further, it is preferable that the synthetic resin layer contains a matting agent to impart matting properties to the surface. In another preferred embodiment of the present invention, the synthetic resin layer to be laminated contains carbon black, thereby imparting conductivity and light-shielding properties. Furthermore, these synthetic resin layers are preferably laminated on the base plastic film by coating.

Examples of materials used as the base plastic film in the light shielding sheet of the present invention include polyethylene film, polypropylene film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, polyethylene terephthalate film, polycarbonate film, nylon film, These are plastic films such as polystyrene film, ethylene vinyl acetate copolymer film, ethylene vinyl alcohol copolymer film, and ionomer film.

Among these, polyester films are preferred in terms of heat resistance, cost, rigidity, and the like.

As the synthetic resin laminated on the above-mentioned base plastic sheet, preferably a thermosetting resin or an ionizing radiation curable resin is used.

Examples of thermosetting resins that can be used in the present invention include phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, and melamine/urea resins. There are cocondensation resins, silicone resins, polysiloxane resins, etc., and if necessary, common additives such as crosslinking agents, curing agents such as polymerization initiators, polymerization accelerators, solvents, viscosity modifiers, and extender pigments are added. etc. can be added and contained.

As curing agents, isoaminates are usually used for unsaturated polyester resins and polyurethane resins, amines are used for epoxy resins, and peroxides such as methyl ethyl ketone peroxide, azobisisobutyronitrile, etc. are used for unsaturated polyester resins. Radical initiators are good (used and used).

As the isocyanate as the curing agent, an aliphatic or aromatic polyisocyanate having a valence of two or more can be used, and an aliphatic isocyanate is preferable from the viewpoint of preventing thermal discoloration and weather resistance of the completed light-shielding film. Specific examples include toluene diisocyanate, xylylene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, and the like.

In addition, in order to accelerate the curing reaction, heating may be performed as necessary after the resin layer is laminated, preferably coated. The heating conditions are usually 40°C for isocyanate-cured unsaturated polyester resins or polyurethane resins.
~60°C for about 1 to 5 days, or in the case of polysiloxane resin, usually at 80 to 150°C for about 1 to 300 minutes.

The ionizing radiation-curable resin used in the present invention is typically one used in electron beam-curable paints and ultraviolet-curable paints. Electron beam curable paints are mainly composed of radically polymerizable double bond-containing polymers, oligomers, and/or monomers as film-forming components, and optionally further contain non-reactive polymers, organic solvents, waxes, and It may contain at least one other additive. - For boat fishing, a material whose main component is a polyfunctional (meth)acrylate-based electron beam curable resin is used. As the ultraviolet curable paint, the above paint contains a photopolymerization initiator and, if necessary, a sensitizer.

Here, ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quantum capable of polymerizing and crosslinking molecules, and usually ultraviolet rays or electron beams are used. As the ultraviolet light source, for example, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light lamp, a metal halide lamp, etc. is used.

As the electron beam source, various electron beam accelerators such as Cockroft-Walton type, Bumpgraph type, resonant transformer type, insulated core transformer type, linear type, dynamidron type, and high frequency type are used, and generally 100~ Electrons having an energy of 1000 keV, preferably 100 to 300 keV are irradiated.

The above-mentioned synthetic resin layer may be laminated to the base plastic, but preferably it can be coated on the base plastic in the form of a paint and cured by heat curing or ionizing radiation.

Matting of these synthetic resin layers can be achieved by incorporating a known matting agent such as microsilica, calcium carbonate, or alumina into the synthetic resin layer, or by forming an uneven matte film using an ionizing radiation-curable resin. After that, the surface can be made matte by irradiating it with ionizing radiation to transfer the uneven shape of the matte film to the synthetic resin layer.

In addition, in order to impart electrical conductivity, known electrically conductive polymers such as polypyrrole, poly(p-phenylene), etc., or electrically conductive ingredients such as carbon black, tin oxide, titanium oxide, etc. may be blended into the synthetic resin pigment paint. Bye.

For imparting light-shielding properties, known colored pigments with hiding properties such as acetylene black, lamp black, carbon black, bone black, mineral black, etc. are used. Carbon black is preferred as a pigment that has light-shielding properties, is electrically conductive, and does not reflect light.

When laminating synthetic resin layers having matte properties, conductivity, and light-shielding properties on both sides of a base plastic film, both layers may be formed from the same material in view of the ease of manufacturing the light-shielding film of the present invention. However, it is advantageous to
It is natural that scales can be formed from different materials that have the same properties.

〔Example〕

The present invention will be explained by examples, but the present invention is not limited by these examples.

Example 1 A polyester film (5-PET manufactured by Music University, thickness 50 μm) was used as a plastic base material, and after corona treatment, a thermosetting paint having the following composition was gravure coated,
A light-shielding sheet having the structure shown in FIG. 1 was manufactured by removing the solvent and curing with hot air at 100°C.

The thickness of the heat-cured paint layer in this case was 15 μm.

fi mini acrylic polyol 100 parts (P
ET! (A-2), manufactured by Dainichiseika Chemical Co., Ltd.) Curing agent: 10 parts of isocyanate (PTCL8 (revised) curing agent, manufactured by Dainichiseika Chemical Co., Ltd.) Solvent:
MEK/toluene = 1/1 80 parts After that, aging was performed at 40°C for 2 days. The physical properties of the obtained film were as follows.

Adhesion Conductive without peeling
9.8X105Ω surface gloss value (60
Specular gloss) 9.2% light shielding
Adhesion without wave light is determined by applying Nichiban's industrial 24 m/m cellophane tape to a light-shielding film with a 2 m/m square grid pattern and then peeling it off. Examined.

Conductivity was measured using a high resistivity meter HirestalP manufactured by Mitsubishi Yuka ■.
It is shown as the average value of 10 measurements.

Surface gloss was measured according to J I5-Z-8741.

The light shielding property was checked by looking through it from a 500W spot lamp at a distance of 15an to see if there were any pinholes or wave light.

Example 2 A polyester film (5-PET manufactured by Music University, thickness 50 μm) was used as a plastic base material, one side of which was corona treated, and then gravure coated with a paint having the following composition.
A single-sided light-shielding sheet was manufactured by removing the solvent and curing with hot air at 0°C. After corona treatment was applied to the other side of this single-sided light-shielding sheet, a double-sided light-shielding sheet was manufactured by the same process as described above (FIG. 2).

The thickness of the heat-cured paint layer in this case was 15 μm on one side.

Urethane acrylate 100 parts Polyfunctional acrylate (DPHA) 10
0 parts Pigment (carbon black) 50 parts Example 3 A polyester film (5-PET manufactured by Music University, thickness 50 μm) was used as the plastic base material, and after corona treatment on one side, the same as used in Example 2 was used. A light-shielding sheet was manufactured by gravure coating the composition and irradiating it with an electron beam.

Comparative Example A sheet obtained by kneading carbon black into PET and forming a film using the conventional technique and then sandblasting the PET has the following physical properties.

Surface gloss value 11.2% Adhesion No peeling Conductivity 6.3XIO' Light shielding No wave light Comparing the physical properties of the sheets of Example 1 and Comparative Example, it is found that according to the present invention, the sheets have almost the same properties as conventional products. It can be seen that the light shielding sheet can be obtained by simple and economical means. Further, the sheet of Example 1 has a lower surface gloss value than conventional products, and has a lower possibility of diffused reflection, which is also an advantage of the present invention.

〔Effect of the invention〕

As explained above, the light-shielding film of the present invention has a structure in which a synthetic resin layer having both matte and light-shielding properties is laminated on one or both sides of a base plastic film, and has both electrical conductivity and light-shielding properties. Carbon black can be used as a substance imparting properties, and a coating can be used for laminating the resin layer. Therefore, according to the present invention, a light-shielding film having the required characteristics can be provided by simple means and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one example of the light-shielding sheet of the present invention, and FIG. 2 is a cross-sectional view showing another example of the present invention. ■... Base plastic film 2... Light shielding layer

Claims (1)

[Scope of Claims] 1. A light-shielding sheet, characterized in that a synthetic resin layer having surface matting properties, conductivity, and light-shielding properties is laminated on one or both surfaces of a base plastic film. 2. The light shielding sheet according to claim 1, wherein the base plastic film is polyester. 3. The light-shielding sheet according to claim 1 or 2, wherein the synthetic resin layer to be laminated is a thermosetting resin or an ionizing radiation-curable resin. 4. The light-shielding sheet according to claim 1, 2 or 3, wherein the synthetic resin layer to be laminated contains a matting agent to impart matte surface properties. 5. The light-shielding sheet according to claim 1, 2, 3 or 4, wherein the synthetic resin layer to be laminated contains carbon black to impart conductivity and light-shielding properties. 6. The light shielding sheet according to claim 1, 2, 3, 4 or 5, wherein the synthetic resin layer is laminated by coating.