JPH07319004A - Shading film - Google Patents

Abstract

PURPOSE:To provide a shading film which is excellent in shading property, slidability, conductivity, and surface grinding property, and is suitable as a shutter, an iris diaphragm, etc., for optical equipment by providing a base material film with a shading layer consisting of a specified material. CONSTITUTION:A shading layer consisting of binder resin, black fine powder 1mum or under in average grain diameter, an organic filter 0.5-10mum in average grain diameter, and a sliding agent 0.1-10mum in average grain diameter is provided on at least one side of a base material film. As the binder resin, setting resin, which shows hardening property by heat, light, etc., or thermoplastic resin, or the like is used. The content of the binder resin is 25-26wt.% to the total weight of the binder resin, the carbon black, the organic filter, and the sliding agent among the shading layer, and the content of the black fine powder is 10-20wt.%, and the organic filler is 20-40wt.%, and the sliding agent is 5-15wt.%. Hereby, a shading member for optical equipment, where the balance between shading property, conductivity, surface grinding property, and slidability is taken, can be gotten.

Description

Detailed Description of the Invention

The present invention relates to a light-shielding film used as a light-shielding member such as a shutter or diaphragm of an optical device such as a photographic camera or a video camera.

[0002]

2. Description of the Related Art Recently, a lot of high performance compact cameras having excellent portability have been put on the market for traveling, leisure and working outdoors. In addition, personal video shooting has increased, and along with this, video cameras have become lighter and more compact, and recently, they have been downsized to the size of a palm. As described above, as optical devices, particularly cameras and video cameras, are made smaller and lighter, the components that make them up are also required to be smaller or lighter.
Conventionally, metal is used for light-shielding members such as shutters and diaphragms, but with the reduction in size, weight and cost,
Synthetic resin films are increasingly used. In such a case, as a light-shielding film used in optical equipment, a polyester film mixed with carbon black is roughened by sandblasting and further coated with an electron-conducting conductive agent (JP-A-1- No. 12503), a thermosetting resin or a room temperature curable resin layer containing carbon black and a lubricant is provided on both sides of a synthetic resin film (JP-A-4-9802).
(Japanese Patent Laid-Open No. 4-62048) and the like in which a synthetic resin layer having a matte surface, a conductive property, and a light-shielding property is laminated on at least one surface of the synthetic resin film. However, these conventional light-shielding films are not always sufficiently satisfactory in terms of their light-shielding properties and economical efficiency. For example, in order to obtain a high light-shielding property, a large amount of carbon black must be mixed in, so that the mechanical and other physical properties of the film change. Further, since the surface is roughened by sandblasting, the unevenness of the surface is easily crushed due to the rubbing of the films, and the film surface becomes glossy after long-term use. In addition, in the case of the one, since carbon black and a lubricant are contained in the thermosetting resin or the room temperature curable resin layer on the film, gloss is likely to be generated on the surface, and in order to reduce the gloss of the surface, carbon having a large particle size is used. Black and lubricant must be used. Therefore, there arises a drawback that the light-shielding property is lowered. Further, in the case of the above, since the light-shielding layer is substantially composed of resin, there is a drawback that the slipperiness is insufficient. As described above, the conventional light-shielding film has a light-shielding property,
Not all of the slidability, conductivity, and matte surface properties were satisfied.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light-shielding film which is excellent in light-shielding properties, slidability, conductivity and surface mattness and which is suitable as a shutter or diaphragm for optical equipment. To do.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, according to the present invention, a binder resin, a black fine powder having an average particle size of 1 μm or less, an organic filler having an average particle size of 0.5 to 10 μm, and an average particle size of 0.1 to 10 μm are provided on at least one surface of the substrate film. There is provided a light-shielding film having a light-shielding layer made of a lubricant.

As the substrate film used in the present invention, synthetic resin films such as polycarbonate, polyester, polystyrene and polyimide are used, and polyester film is particularly preferable. In addition to the transparent base film, a foamed polyester film or a synthetic resin film containing a black pigment such as carbon black or another pigment can be used. In this case, the base film can be selected appropriately depending on its use. For example, a synthetic resin film containing a black pigment can be used when high light-shielding property is required, and a transparent or foamed synthetic resin film can be used otherwise. The thickness of the base film varies depending on the purpose of use and field of use, but is usually 25 to 190 μm, preferably 5
It is selected in the range of 0 to 125 μm. In addition, the base film can be subjected to anchor treatment or corona treatment, if necessary. This improves the adhesiveness between the synthetic resin layer and the base film.

The binder resin used in the present invention is
A curable resin, a thermoplastic resin, or the like that exhibits curability by heat or light is used. Thermosetting resins are preferably used in the present invention. Examples of such resins include acrylic, urethane, phenol, melamine, urea, diallyl phthalate, polyester, epoxy and alkyd resins. And the like, and these can be used alone or in combination of two or more. Of these, a thermosetting acrylic resin is particularly preferable, and it has excellent adhesiveness to a base film and excellent scratch resistance. Examples of the thermoplastic resin include thermoplastic acrylic resin, vinyl chloride resin, butyral resin, styrene / butadiene resin and the like. The content of the binder resin is 25 to 65% by weight, preferably 35 to 55% by weight, based on the total weight of the binder resin, carbon black, organic filler and lubricant in the light-shielding layer. ,
The adhesiveness between the base film and the light-shielding layer is lowered, and when it is more than this range, it becomes difficult to balance the light-shielding property, the slidability, the conductivity and the matte surface property.

As the black fine powder used in the present invention, various conventionally known ones such as carbon black and aniline black are used, and their average particle diameter is 1 μm or less,
It is preferably 0.5 μm or less. When the average particle size is larger than this range, the surface matte property is sufficient, but the light-shielding property is deteriorated, which is not preferable. The content of the black fine powder is 10 to 20% by weight, preferably 12 in the light shielding layer.
If it is less than this range, the light-shielding property and the conductivity will be deteriorated, and if it is more than this range, the matte property of the surface will be poor and the cost will be high.

Examples of the organic filler used in the present invention include various synthetic resin particles such as melamine resin, benzoguanamine resin, benzoguanamine / melamine / formalin condensate, acrylic resin, urethane resin and styrene resin. It is also possible to use one kind or a mixture of two kinds. Particularly, a condensate of benzoguanamine and formaldehyde is preferable from the viewpoint of improving the matte property and the slidability of the film surface. The shape of the organic filler may be a spherical product or a crushed product, but the use of the spherical product is preferable because the static friction coefficient is lowered and the slidability is improved. The content of the organic filler is 20 in the light shielding layer.
It is -40% by weight, preferably 25-35% by weight, and if it deviates from this range, the matteness and slidability of the surface deteriorate. The average particle size of the organic filler is 0.5 to 10 μm, preferably 1 to 5 μm. When the average particle size is larger than this range, the light-shielding property is lowered, and when it is small, the matte effect on the film surface becomes insufficient.

As the lubricant used in the present invention, various conventionally known lubricants, for example, hydrocarbon lubricants such as polyethylene, fatty acid lubricants such as stearic acid, alcohol lubricants such as stearyl alcohol, solids such as molybdenum disulfide, etc. Lubricants, silicone resin particles, fluorine-containing resin particles, crosslinked polymethylmethacrylate particles, crosslinked polystyrene particles and the like can be mentioned. In particular, the use of fluorine-containing resin particles is preferable because the slidability of the light shielding layer is improved. The lubricant may or may not have a spherical shape, but a spherical shape is preferable in terms of slidability and surface matteness. The content of the lubricant is 5 to 15% by weight, preferably 7 to 13% by weight in the light shielding layer.
If it deviates from this range, the slidability and the surface matting effect will be deteriorated. The average particle size of the lubricant is 0.1
The average particle size is 10 μm, preferably 0.15 to 5 μm. When the average particle size is larger than this range, the sliding effect is reduced, and when the average particle size is smaller than this range, the matte property of the film surface becomes poor.

The light-shielding film of the present invention can be obtained by coating one or both surfaces of a base film with a coating liquid containing a binder resin, black fine powder, an organic filler and a lubricant. The solvent of the coating liquid is water or organic solvent,
It can be a mixture of water and an organic solvent or the like. Also,
The binder resin may be dissolved or dispersed in the solvent.

In the light-shielding film of the present invention, the light-shielding layer may be a single layer or may be composed of two or more layers. For example, a light-shielding layer composed of two layers can be formed by coating a coating solution containing a binder resin and a lubricant on a layer composed of a binder resin, black fine powder and an organic filler. In this case, since the outermost layer is a layer containing a lubricant, higher slidability can be obtained. Further, a light-shielding layer consisting of three layers is formed by forming a layer consisting of a binder resin and black fine powder on a layer consisting of a binder resin and an organic filler, and further forming a layer consisting of a binder resin and a lubricant thereon. Can be formed. Even when the light shielding layer is composed of two or more layers, the ratio of each component contained in the entire light shielding layer is the same as the above range. The thickness of the light-shielding layer varies depending on the usage of the light-shielding film, but is generally 2 to 30 μm, and when used as a camera shutter, 3 to 20 μm,
It is preferably 5 to 15 μm.

[0012]

EXAMPLES The present invention will be described in more detail with reference to examples. All parts and% shown below are based on weight.

Example 1 On both sides of a carbon black-containing polyester film having a thickness of 50 μm, an undercoat layer made of a saturated polyester resin (trade name “Byron”, manufactured by Toyobo Co., Ltd.) (thickness:
1 μm) and apply the coating solution of the following formulation at 100 ° C
And dried for 2 minutes to obtain a light shielding film having a thickness of 10 μm. In addition,
The thickness of the entire light-shielding film was 72 μm. (Coating liquid) Thermosetting acrylic emulsion (Movinyl 767, solid content 46%; Hoechst Synthetic Co., Ltd.) 29.3 parts Carbon black (EP-510BLACK solid content 37%; Dainichiseika Co., Ltd.) 12. 2 parts Benzoguanamine / melamine / formaldehyde resin (Eposter M30; Nippon Shokubai Co., Ltd.) 9.0 parts Fluorine-containing resin emulsion (Teflon FEP solid content 54%; Mitsui DuPont Co., Ltd.) 5.6 parts Ion-exchanged water 43.8 copies

Example 2 In Example 1, 35.9 acrylic emulsion was used.
And a benzoguanamine / melamine / formaldehyde resin in an amount of 6.0 parts were obtained in the same manner as above to obtain a light-shielding film.

Example 3 In Example 1, the acrylic emulsion was mixed with 35.9.
Parts, carbon black was 8.1 parts, and fluororesin emulsion was 2.8 parts to obtain a light-shielding film in the same manner.

Example 4 On both sides of a carbon black-containing polyester film having a thickness of 50 μm, a subbing layer (thickness: made of saturated polyester resin (trade name “Byron”, manufactured by Toyobo Co., Ltd.)).
1 μm) to apply a coating solution of the following formulation (A),
After drying at 00 ° C. for 2 minutes, a coating solution of the following formulation (B) was applied and dried at 100 ° C. for 2 minutes to obtain a light-shielding film having a thickness of 12 μm. The total thickness of the light shielding film was 76 μm. (Coating liquid A) Thermosetting acrylic emulsion (Movinyl 767 solid content 46%; Hoechst Synthetic Co., Ltd.) 32.6 parts Carbon black (EP-510BLAK solid content 37%; Dainichi Seika Co., Ltd.) 13. 5 parts Benzoguanamine / melamine / formaldehyde resin (Eposta-M30; Nippon Shokubai Co., Ltd.) 10.0 parts Ion-exchanged water 43.9 parts (Coating liquid B) Thermosetting acrylic emulsion (Movinyl 747 solid content 43%; Hoechst) Synthetic Co., Ltd. 41.9 parts Fluorine-containing resin emulsion (Teflon 30J solid content 60%; Mitsui DuPont Co., Ltd.) 3.3 parts Ion-exchanged water 54.8 parts

Comparative Example 1 In Example 1, 39.1 acrylic emulsion was used.
Parts, 4.1 parts of carbon black, benzoguanamine /
A light-shielding film was obtained in the same manner except that the melamine / formaldehyde resin was 4.5 parts and the fluororesin emulsion was 11.1 parts.

Comparative Example 2 A light-shielding film was obtained in the same manner as in Example 1, except that the fluorine-containing resin emulsion was not added.

Comparative Example 3 A light-shielding film was obtained in the same manner as in Example 1 except that the benzoguanamine / melamine / formaldehyde resin was not added.

Comparative Example 4 A light-shielding film was obtained in the same manner as in Example 1, except that the fluorine-containing resin emulsion and the benzoguanamine / melamine / formaldehyde resin were not added.

Comparative Example 5 A light-shielding film was obtained by sandblasting both sides of a carbon black-containing polyester film having a thickness of 75 μm.

These light-shielding films were tested by the following method, and the results are shown in Table 1.

Test 1 (Light-shielding property) A light-shielding film was exposed to light of 100,000 lux, and A was placed behind it.
A black-and-white film with SA speed of 3200 was placed, and it was examined whether or not the black-and-white film was exposed. The evaluation was carried out on a scale of 5, with 1 being completely exposed and 5 being completely shielded from light. Test 2 (conductivity) The surface resistivity of the light-shielding film was measured according to JIS K-6911. Test 3 (Surface Matte Property) The glossiness of the light-shielding film was measured according to JIS Z-8741. The evaluation was carried out on a scale of 5, with 1 having the highest gloss and 5 the lowest. Test 4 (Sliding property) The static friction coefficient of the light-shielding film was measured based on ASTM D-1984. The evaluation was carried out in five stages, with the highest friction coefficient being 1, and the lowest friction coefficient being 5.

[0024]

[Table 1]

[0025]

As is apparent from the above examples, the light-shielding film of the present invention has a light-shielding layer made of a binder resin, black fine powder, organic filler, and lubricant on one or both sides of the base film. Thus, it has a well-balanced light-shielding property, conductivity, matte surface and slidability, and is suitable as a light-shielding member for optical devices such as shutters for optical devices and diaphragms. Further, in the light-shielding film of the present invention, the degree of light-shielding can be easily changed by adjusting the content of carbon black in the light-shielding layer, and it can be applied to various light-shielding materials for optical devices.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masatoshi Tomiki 4-11-2 Ginza, Chuo-ku, Tokyo Somer Co., Ltd. (72) Inventor Yoichi Tashiro 4-11-2 Ginza, Chuo-ku, Tokyo Somer Within the corporation

Claims (3)

[Claims] 1. A binder resin, a black fine powder having an average particle size of 1 μm or less, an organic filler having an average particle size of 0.5 to 10 μm, and an average particle size of 0.1 on at least one surface of a substrate film.
A light-shielding film having a light-shielding layer made of a lubricant of 10 μm. 2. The light-shielding layer has a binder resin content of 2
The light-shielding film according to claim 1, wherein the content of the black fine powder is 5 to 65% by weight, the content of the black fine powder is 10 to 20% by weight, the content of the organic filler is 20 to 40% by weight, and the content of the lubricant is 5 to 15% by weight. 3. The light-shielding film according to claim 1, wherein the light-shielding layer is composed of two or more layers.