JPH0926647A - Shading paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain such a light-shielding paper that the size of the paper is always kept const. without changing and a photosensitive material such as a photographic film can be stored and transferred without exposure to light till the material is used, by laminating a biaxially oriented film between a paper base layer and a conductive layer. SOLUTION: A surface varnish layer 1 is formed to protect a printing layer 2. The printing layer 2 is formed to record characters or marks necessary for the function or to raise the value of the product, and a conductive layer 5 is formed by using a conductive ink containing an org. compd. or carbon black. A biaxially oriented film 4 laminated between the paper base layer 3 and the conductive layer 5 is a film having moisture preventing property which does not permeate the water content from inside of the light-shielding paper or does not absorb water content generating from outside. As for the biaxially oriented film 4, a biaxially oriented polyester such as biaxially oriented polyethylene terephthalate, or a biaxially oriented polyethylene such as biaxially oriented polypropylene and biaxially oriented polyethylene are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding paper made of a laminated material having a light-shielding property for packaging a photosensitive substance so as not to cause a change in the photosensitive substance.

[0002]

2. Description of the Related Art A conventional photosensitive material is a carbon black having a light-shielding property in order to prevent the photosensitive material from being exposed to sunlight or artificial light while being transported or stored until it is used. It was packaged with light-shielding paper containing the above ingredients. The light-shielding paper is generally formed of a laminated light-shielding paper including a layer having a light-shielding property. Also, the photographic film provided with a photosensitive material on the surface,
In order to improve the light-shielding property of a photographic film, not only the above-mentioned light-shielding paper but also a photographic film cartridge, a photographic film spool, a photographic cartridge, and other members are used to package the photographic film. However, even when the above-mentioned member having a light-shielding property is used, the exposed portion of the photographic film was wrapped with the above-mentioned light-shielding paper for the purpose of preventing light exposure.

The light-shielding paper used for the photographic film has conventionally been made of a laminated structure using paper as a base material. For example, a surface coat varnish layer / printing layer / paper layer / conductive layer is laminated. The material was used. The conductive layer is for preventing static marks from being generated on the photosensitive layer due to static electricity generated when the photosensitive film is drawn out and used, and is made of an ink containing carbon black and an inorganic compound. Further, a substance having a light-shielding property such as carbon black is added to this conductive layer.

[0004]

However, in the light-shielding paper having a laminated structure used together with the conventional photographic film, moisture is generated from the inside of the paper layer which is the base material of the light-shielding paper, or moisture is absorbed from the outside. Therefore, the paper used as the base material of the light-shielding paper shrinks, expands, distorts the light-shielding paper, or exposes part of the photographic film, or there is a slight gap between the light-shielding paper and the photographic film. Occasionally, light may enter through the gap and the photographic film may be exposed to light, and the conventional opaque paper cannot sufficiently shield the photographic film.

The present invention has been made to solve the above problems, and the size of the light-shielding paper is always constant and does not change, and the photosensitive material such as a photographic film is held without being exposed to light before use. The present invention provides light-shielding paper that can be transported.

[0006]

The present invention provides a light-shielding paper in which a paper used together with a photosensitive film such as a photographic film is used as a base material and a conductive layer having a light-shielding property is provided between a paper base material layer and a photosensitive material. It is a light-shielding paper provided with a biaxially stretched film between the paper base layer and the conductive layer.

[0007]

In the light-shielding paper of the present invention, since the biaxially stretched film is provided between the paper base layer and the conductive layer, moisture generated from the light-shielding paper or moisture from the outside is biaxially moisture-proof. The stretched film cannot evaporate outside or absorb inside, and the size of the light-shielding paper does not change, and the photographic film once packaged can be kept in a light-shielded state.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The light-shielding paper of the present invention is used together with a light-sensitive film coated with a light-sensitive substance such as a photographic film, and is in a light-shielded state in which light is not applied from the outside. A shading paper which is an embodiment of the present invention is shown in FIG. First, the surface coating varnish layer (1) is the printing layer (2).
The material used for the surface coat varnish layer (1) can be the same as the conventional one, and polyethylene terephthalate, other thermoplastic resins, lacquer, varnish, etc. can be used. used.
Further, the print layer (2) is provided for the purpose of increasing characters, symbols, or commercial value necessary for the function. The reason for providing the paper base material layer (3) as the base material of the light-shielding paper is as follows.
This is because it is used as a support. In addition, the conductive layer (5)
Is formed from a conductive ink such as an ink containing an inorganic compound or carbon black, and a substance having a light-shielding property such as carbon black is added to the conductive layer (5). Further, the biaxially stretched film (4) provided between the paper base material layer (3) and the conductive layer (5) has a moisture-proof property that does not allow the moisture generated from the light-shielding paper to be discharged to the outside and does not absorb the moisture from the outside. Films having the same are used, and as these biaxially stretched films, biaxially stretched polyesters such as biaxially stretched polyethylene terephthalate, biaxially stretched polyolefins such as biaxially stretched polypropylene and biaxially stretched polyethylene are used. In this example, biaxially stretched polyethylene terephthalate was used as a biaxially stretched film (4).
Used as Hereinafter, examples and comparative examples will be described.

[0009]

【Example】

Laminated structure of light-shielding paper <Example> Surface coat varnish layer (1) / printing layer (2) / paper base material layer (3) / biaxially stretched film layer (biaxially stretched polyethylene terephthalate) (4) / conductive layer ( 5) <Comparative example> Surface coating varnish layer (1) / printing layer (2) / paper base material layer (3) / conductive layer (5) -Experimental method A bag of 5 cm in length and width is made from the light-shielding paper having the above-mentioned configuration,
Insert 13 g of calcium chloride into it, seal it, and store it at a temperature of 40 ° C and a humidity of 90%, and after 3 hours and 6 hours,
After 9 hours and 24 hours, the bag was weighed to measure the water vapor permeability. A cross-sectional view of the light-shielding paper of the above embodiment is shown in FIG.
2 shows a cross-sectional view of the light-shielding paper of the comparative example. The results are shown in Table 1 below.

[0010]

[Table 1]

Therefore, from Table 1, the light-shielding papers of the examples of the present invention have extremely low water vapor permeability as compared with the comparative example which is a conventional light-shielding paper. Therefore, the proportion of water discharged from the light-shielding paper and absorbed by the light-shielding paper from the outside is extremely small, and the size of the light-shielding paper is not deformed by the proportion of water. Therefore, by using the light-shielding paper of the present invention for packaging, the photosensitive material such as photographic film is always kept in a light-shielded state.

Further, the biaxially stretched film is provided only on the side of the base material of the paper which comes into contact with the photosensitive material such as the photographic film. Although not provided, it is needless to say that the deformation prevention of the light-shielding paper is further improved by providing the biaxially stretched film on both sides of the paper base material.

[0013]

As described above, the light-shielding paper of the present invention is
By providing a biaxially stretched film between the paper base layer and the conductive layer, it is possible to prevent water from being discharged from the light-shielding paper and from being absorbed from the outside to the light-shielding paper. It is possible to prevent deformation of the light-shielding paper due to absorption. Therefore, the light-sensitive material packaged by the light-shielding paper is always shielded from light, and light from the outside does not pass through the light-sensitive material and the light-sensitive material is not exposed to light.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a shading paper according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a conventional shading paper.

[Explanation of symbols]

 1 ... Surface coat varnish layer 2 ... Printing layer 3 ... Paper base layer 4 ... Biaxially stretched film layer 5 ... Conductive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 27/10 B32B 27/10 27/18 27/18 J B65D 81/30 B65D 81/30 C D21H 27/36 D21H 1/02 C

Claims (1)

[Claims] 1. A light-shielding paper comprising a paper for use with a photosensitive film coated with a photosensitive material as a base material, and a conductive layer provided on the side of the paper base material layer in contact with the photosensitive material, wherein the paper base material layer and the conductive layer are provided. A light-shielding paper, characterized in that a biaxially stretched film is provided between the two.