JPS61118746A - Reflex photographic material - Google Patents

Abstract

PURPOSE:To prevent penetration of a processing soln. etc., from the cut section of a base by using a film base of a thermoplastic resin composed essentially of a polyester resin contg. a white pigment having as a main component, titanium oxide specified in particle diameter and subjected to surface treatment. CONSTITUTION:The thermoplastic resin to be used for the film base of this reflex photographic material is composed essentially of a polyester resin having a film thickness of 50-300mum, and a whole visible light transmittance of <=20% for giving sufficient whiteness, and contg. a white pigment subjected to surface treatment in an amt. of >=90wt% of the total white pigment, having an average particle diameter of 0.1-0.5mum substantially not contg. >=50mum particles and composed of titanium oxide. A photographic sensitive emulsion layer is formed on at least one side of the film base made nontransparent and opaque by using a material, thus permitting the obtained reflex photographic material to be prevented from penetration of a processing soln., etc., and to be superior in whiteness, nontransmittance, and gloss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to reflective photographic materials. Here, the term "reflective photographic material" refers to a material that uses an opaque material as a support and has a photographic layer on it, in contrast to a so-called transmission photographic material that projects a photographic image using transmitted light and uses the projected image. Generally speaking, it refers to a photographic material commonly called photographic paper for directly viewing the photographic image formed on the photographic layer using reflected light.

[Prior Art] Conventionally, as a support for reflective photographic materials, polyethylene-coated paper is generally used, which is a base paper made from bulbs and provided with a polyethylene layer kneaded with a white pigment or the like. However, in reflective photographic materials using polyethylene coated paper as a support.

The unevenness of the surface of the adjacent base paper support results in a rough, rippled, glossy surface that significantly impairs the brightness, sharpness, and resulting beauty of the photographic image. Also,
Both sides of the base paper of the support are coated with a water-impermeable polyethylene membrane, but the cut side of the base paper is not coated, so the processing solution, etc. seeps in from there, and over time, the processing solution may penetrate into the photographic layer. There were drawbacks such as having an adverse effect on the obtained photographic image.

As a method to eliminate the above-mentioned drawbacks, there is a method (sometimes proposed) in which only a thermoplastic resin film is used as a support without using base paper.

JP-A-49-114921 and JP-B-55-5104 disclose a method of filling a polystyrene resin film with a white pigment, but these films are hard and
It has the disadvantage of being brittle. Polyester resins such as polyethylene terephthalate are superior in terms of physical properties such as mechanical strength of this film, and technologies using this polyester resin are disclosed in British Patent Nos. 1,563,591 and 1,563,592@ discloses a method of adding barium sulfate to a polyester resin and stretching the resin. However, this method does not provide sufficient whiteness as a support for reflective photographic materials, as evidenced by the extensive use of fluorescent brighteners and other pigments in the examples of the patent. . Furthermore, as a result of stretching, voids are formed around the barium sulfate particles, and when a photographic layer is coated, the resolution of the image obtained becomes insufficient. Also, in Special Publication No. 56-4901,
A technique using barium sulfate and titanium oxide in combination has been disclosed. The patent states that saturated polyester resins are also suitable in addition to olefin resins, styrene resins, vinyl chloride resins, polyacrylate resins, polycarbonate resins, etc. as thermoplastic resins that can be used. It cannot be applied to polyester resins for the following two reasons. The first point is that the refractive index values of barium sulfate and polyester resin are close, and suitable whiteness cannot be obtained unless stretched, and the patent does not disclose anything about adding barium to polyester resin. Secondly, if titanium oxide is directly added to a polyester resin and stretched, voids will be created around the particles, making it impossible to obtain a suitable degree of whiteness, and as mentioned above, the resolution of photographic images will also be insufficient. As mentioned above, it has not yet been satisfactory as a reflective photographic material.

[Object of the Invention] The present invention has been made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to prevent penetration of photographic processing liquid etc. from the cut surface of the support, and to improve whiteness, opacity, and gloss. To provide a reflective photographic material having excellent resolution and rough resolution of photographic images.

[Structure of the Invention] The above object of the present invention is to provide a white pigment containing 90% by weight or more of titanium oxide which has been subjected to a surface treatment and has an average particle diameter of 0.1 to 0.5 μm and does not substantially contain particles of 50 μm or more. Achieved by a reflective photographic material in which a photosensitive photographic emulsion layer is coated on at least one side of a film support containing a thermoplastic resin whose main component is a polyester resin with a film thickness of 50 to 300 μm and a total visible light transmittance of 20% or less. be done.

[Specific structure of the invention] The thermoplastic resin whose main component is a polyester resin used in the present invention (hereinafter referred to as the resin of the present invention) is not only a thermoplastic resin consisting only of polyester, but also a thermoplastic resin whose main component is a polyester resin. It also includes polyesters to which other polymers, additives, etc. are added within a range that does not practically change the resin properties of the polyester.

The polyester resin used in the present invention includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, ethylene glycol, 1
．． Polymers of condensates with glycols such as 3-propanediol and 1゜4-butanediol, such as polyethylene terephthalate, polyethylene 2,6-dinaphthalate, polypropylene terephthalate, polybutylene terephthalate, etc., or copolymers thereof. Can be mentioned. The polyester resin used in the present invention is polyethylene terephthalate (hereinafter abbreviated as PET).
is preferred. PET resin film does not penetrate water, has excellent smoothness, has excellent mechanical properties such as tensile strength and tear strength, has excellent dimensional stability such as heat shrinkage, and has excellent chemical resistance during development processing. It is something that exists.

Phenol/tetrachloroethane (60
/40 weight ratio) in a mixed solvent at 20'C, the intrinsic viscosity is preferably 0.4 to 1.0, more preferably 0.
．． It is 5 to 0.8.

The white pigment used in the present invention is 901% of the total white pigment.
% or more has an average particle diameter of 0.1-0.
It is titanium oxide with a diameter of 5 μm and substantially no particles larger than 50 μm. Here, the surface treatment applied to titanium oxide refers to surface treatment performed with an aluminum compound having an oxygen bond or hydroxyl group bond, such as aluminum, and/or a silicon compound 1 such as silicic acid, or an attack of the treatment. This refers to a treatment in which the titanium oxide particles are further surface-treated with a metal soap, a surfactant, a coupling agent, etc. to make the titanium oxide particles compatible with the resin of the present invention.

As the titanium oxide used in the present invention, titanium oxide (rV) having a rutile type and/or anatase type structure is preferably used. The refractive index of titanium oxide used in the present invention (n-2.5 to 2.75) is extremely large compared to the refractive index of the resin of the present invention (for example, the refractive index of PET, 1.66), so it is difficult to use as a photographic material. When used in a support, it has excellent light reflection ability and the resulting photographic image has excellent resolution.

The titanium oxide used in the present invention has an average particle size of 0.1 to
It is 0.5 μm and does not substantially contain particles of 50 μm or more, but if the average particle size exceeds the range of the present invention, it is difficult to obtain effective reflectivity, opacity, and whiteness. Even if the particle size is within the range of 0.1 to 0.5 μm, it may re-agglomerate in the resin of the present invention to form granules with a size of substantially 50 μm or more. Over time, it becomes easy to tear, resulting in a film that lacks smoothness and gloss, and also loses the mechanical strength inherent in polyester.

Furthermore, when a photographic layer is provided, white spots appear as defects in the resulting photographic image, which is not preferable as a photographic material. Therefore, titanium oxide is dispersed and molded in a resin so that its particle size does not exceed 50 μm, and it does not re-agglomerate to form particles larger than 50 μm.

The proportion of the white pigment contained in the resin of the present invention is determined from the viewpoint of the whiteness and stretchability of the support film.
Preferably, the white pigment is 10 to 50 parts by weight,
More preferably 15-30! It is a quantity part.

In the white pigment of the present invention, examples of the white pigment that can be used in combination with the titanium oxide of the present invention include one or more inorganic pigments such as barium sulfate, silica, talc, and calcium carbonate. The amount of the white pigment that can be used in combination with these pigments should not exceed 10 parts by weight per 100 parts by weight of the resin of the present invention.

The support of the present invention may contain other commonly used additives, such as fluorescent brighteners, dyes, ultraviolet absorbers, antistatic agents, etc., as long as they do not impair the purpose of the present invention.

In order to mold the support of the present invention, the resin of the present invention to which the white pigment of the present invention has been added is extruded from a slit die, and then ground on a rapidly cooling surface such as a rotating drum to form an amorphous sheet. After that, the glass transition temperature (To
) or more and 130° C. or less, the stretching can be carried out sequentially or biaxially in the longitudinal or transverse direction uniaxially or simultaneously.

At this time, in order to satisfy the mechanical strength and dimensional stability of the film support, it is preferable that the stretching be carried out in an area ratio of 4 to 16 times. After stretching, it is preferable to perform heat setting and heat relaxation.

The film thickness of the support of the present invention is 50 to 300 μm, preferably 75 to 250 μm. If it is thinner than 50 μm, it will not be stiff as a support and will wrinkle easily. Moreover, if it exceeds 300 μ-, there will be drawbacks such as being too thick and making it inconvenient to handle.

Further, the total visible light transmittance of the support of the present invention is set to 20% or less, more preferably 10% or less, in order to obtain sufficient opacity and whiteness when viewed with the naked eye. Therefore, the film thickness of the support of the present invention is 50 to 300 μm, preferably 75 to 250 μm.
The amount of the white pigment added and the stretching ratio are selected so that the total visible light transmittance is 20% or less, preferably 10% or less.

A light-sensitive photographic emulsion layer is coated on one side of the support of the present invention, which is formed as described above and is opaque and whitened. Surface activation treatment such as corona discharge and/or coating of a subbing layer can be performed.

The reflective photographic material of the present invention can be applied to any photographic material that uses a support, for example, there are no limitations such as black and white or color, and the photographic constituent layers include a light-sensitive photographic emulsion layer,
There are no particular restrictions on the number or order of layers such as an intermediate layer, a protective layer, a single filter layer, a back coat layer, etc., and the invention can be applied.

The photographic emulsion layer in the present invention is a normal silver halide emulsion layer, and for example, silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion, etc. are preferably used. can. In addition, this layer can contain a coupler for creating a color image, and it is also possible to contain a hydrophilic polymer substance other than gelatin as a binder, such as polyvinyl alcohol, polyvinylpyrrolidone, etc. It is.

Furthermore, the silver halide emulsion layer can be made to have a sensitive wavelength range of ms using cyanine dyes, merocyanine dyes, etc., and may also contain various other photographic additives such as anti-capri agents, gold, sulfur, etc. Chemical sensitizers, hardeners, antistatic agents, etc. can be preferably added. Therefore, the present invention is effective regardless of whether the photographic material according to the present invention is developed in black and white or in color with or without a coupler.

[Specific Effects of the Invention] As explained above, according to the reflective photographic material of the present invention, there is no penetration of photographic processing liquid etc. from the cross section of the support, so the preservation stability of photographic images over time is excellent, and the whiteness and opacity are improved. A reflective photographic material having excellent gloss, excellent resolution of photographic images, and suitable for viewing and recording can be obtained.

[Specific Examples of the Invention] Hereinafter, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited thereto.

Example 1 A composition consisting of 100 parts by weight of PET resin with an intrinsic viscosity of 0614 and 25 parts by weight of anatase-type titanium oxide (IV') with an average particle diameter of 0.2 μ-treated with alumina and silica was melted and then melted using a slit die. The mixture was then extruded onto a quenched rotating drum to obtain an amorphous sheet with a thickness of 1,611 m.

This amorphous sheet was stretched 3.0 times in the longitudinal direction at 90°C and then 3.0 times in the transverse direction at 110°C to obtain a rough 220°
The photographic film support of the present invention is heat-set at ℃
1 The film thickness of the obtained photographic film support was 180 μm. Further, in order to evaluate the opacity, the total visible light transmittance was measured using a digital turbidity meter model T-2600DA (manufactured by Tokyo Denshoku Co., Ltd.). The results are shown in Table 1.

After subbing the above photographic film support, a gelatin-silver halide photographic emulsion, which is commonly used in color photographic paper, is coated on the surface to a dry film thickness of 15 μm, The desired reflection photographic material was prepared.

A heavy line chart for resolution measurement was printed on the reflection photographic material sample 1 obtained above, and after exposure, color development was performed in the usual manner, and the optical density difference of the dense line print image was measured using a microdensitometer PDM- 5 (manufactured by Konishiroku Photo Industry Co., Ltd.), and the value expressed by the following formula was defined as the resolution.

Difference in density between [)taax and ()win of the dense line print image of 5 lines/Ill Also, the spectral reflectance of 380 to 780tv measured with a spectrophotometer 320 model (manufactured by Hitachi, Ltd.) for the white background area after development J
Itching was measured according to IS-Z-8722 (1982), the whiteness (L value) was determined, and the whiteness was measured at 20% using a gloss meter.
J l5-Z-8741 Method 4
The glossiness (%) was measured. The results are also shown in Table 1.

In the above reflective photographic material sample 1, alumina, a white pigment contained in a photographic film support, anatase type titanium oxide (IV) surface-treated with silica, alumina,
Rutile titanium oxide surface treated with zinc stearate (
Reflection photographic material sample 2 was prepared in the same manner except that rV)
I got it.

Furthermore, in Sample 1, the white pigment was made of 25 parts by weight of anatase-type titanium (IV) without surface treatment (
Reflection photographic sample 3 was obtained in the same manner except that the average particle diameter was 0.2 μs).

Furthermore, in the above sample 1, anatase type titanium oxide (IV) 1 whose white pigment was surface-treated with alumina and silica
5 heavy agricultural products (average particle size 0.2μm) and average particle size 0
．． Reflection photographic material sample 4 was obtained in the same manner except that 1011 parts of 6 μm calcium carbonate mixed white pigment was used instead.

Samples 2.3 and 4 were exposed and developed in the same manner as Sample 1, and the characteristics of each sample were measured in the same manner as Sample 1. The results are also shown in Table 1.

Table 1 From the results in Table 1, both the present invention and the comparative example have excellent opacity, but the reflective photographic material of the present invention has superior whiteness and gloss, and even better resolution than the comparative sample. I understand that. Further, there was no permeation of photographic processing liquid etc. from the cross section of the support, and no change in the image over time due to residual processing liquid was observed.

Claims (1)

[Claims] 90% titanium oxide that has been surface-treated to have an average particle size of 0.1 to 0.5 μm and substantially contain no particles larger than 50 μm.
A photosensitive photographic emulsion layer is coated on at least one side of a film support made of a thermoplastic resin whose main component is a polyester resin containing a white pigment containing at least % by weight and a film thickness of 50 to 300 μm and a total visible light transmittance of 20% or less. A reflective photographic material characterized by: