JPH0422506B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a reflective photographic material and a method for producing the same. Here, the reflection photographic material is a material in which an opaque material is used as a support and a photographic layer is provided on the so-called transmission photographic material, in which a photographic image is projected by transmitted light and the projected image is used. Usually, it refers to a photographic material called a 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 pulp and provided with a polyethylene layer kneaded with a white pigment or the like. However, in reflective photographic materials using polyethylene-coated paper supports, the unevenness of the surface of the adjacent base paper support results in a glossy surface with rough ripples, which impairs the brightness, sharpness, and resulting beauty of the photographic image. quality is significantly impaired. Also, both sides of the base paper of the support are covered with a water-impermeable polyethylene thin film, but since the cut side of the base paper is not coated, the developing processing solution etc. seeps in from there, and over time the processing solution is transferred to the photographic layer. However, there were drawbacks such as an adverse effect on the photographic images obtained. As a method for solving the above-mentioned drawbacks, several methods have been proposed in which only a thermoplastic resin film is used as a support without using base paper. In JP-A-49-114921 and JP-A-55-5104,
Methods of filling polystyrene resin films with white pigments have been disclosed, but these films have the drawback of being hard and brittle. Polyester resins such as polyethylene terephthalate are superior in terms of physical properties such as mechanical strength of this film, and a technology using this polyester resin has been patented in the UK.
No. 1563591 and No. 1563592 disclose 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. This is clear from the extensive use of optical brighteners and other pigments in the examples of the same 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. Further, Japanese Patent Publication No. 56-4901 discloses a technique in which barium sulfate and titanium oxide are used in combination. The patent states that the thermoplastic resins that can be used include olefin resins, styrene resins,
It has been stated that saturated polyester resins are suitable in addition to vinyl chloride resins, polyacrylate resins, polycarbonate resins, etc., but 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. Second, if titanium chloride is directly added to a polyester resin and then 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 the first object of the present invention is to prevent the penetration of photographic processing liquid etc. from the cross section of the support and to make the support thin. A second object of the present invention is to provide a reflective photographic material having excellent whiteness, opacity, and gloss as well as excellent resolution of photographic images.A second object of the present invention is to provide a method for producing a reflective photographic material having the above characteristics. It is to provide. [Structure of the Invention] The above-mentioned first object of the present invention is to provide fine particles A dispersed in a resin with voids around them and white particles dispersed in a resin with substantially no voids around them. Film thickness of thermoplastic resin containing Pigment B and mainly composed of polyester resin: 40~
This is achieved by using a reflective photographic material having a film support having a diameter of 300 μm and a total visible light transmittance of 20% or less and a light-sensitive photographic emulsion layer coated on at least one side. The second object of the present invention is to provide fine particles A which have a weak adhesive force to the thermoplastic resin and are inert to the thermoplastic resin, and which are contained in a thermoplastic resin containing polyester resin as a main component. After melting and rapidly cooling a resin composition containing a white pigment B that has strong adhesive strength with resin to form an amorphous sheet, the fine particles A
A white pigment with a film thickness of 40 to 300 μm and a total visible light transmittance of 20% or less, which is obtained by stretching in biaxial directions so as to form voids around the white pigment B and to substantially prevent voids from forming around the white pigment B. forming a film support;
This is achieved by a method for producing a reflective photographic material in which a light-sensitive photographic emulsion layer is coated on at least one side of the white film support. [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, and naphthalene dicarboxylic acid, and glycols such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Polymers of condensates of, for example, polyethylene terephthalate, polyethylene 2,6 dinaphthalate, polypropylene terephthalate, polybutylene terephthalate, etc., or copolymers thereof. The polyester resin used in the present invention is polyethylene terephthalate (hereinafter referred to as PET).
) is preferred. PET resin film is
It does not permeate 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. The intrinsic viscosity of the resin of the present invention measured at 20° C. in a mixed solvent of phenol/tetrachloroethane (60/40 weight ratio) is preferably 0.4 to 1.0, more preferably 0.5 to 0.8. The fine particles A used in the present invention are fine particles that have weak adhesion to the resin of the present invention and have almost no reactivity with the resin, such as barium sulfate, barium carbonate, lithopone (Z _o S + B _a SO ₄ ). , inorganic fine particles such as rutile type or anatase type titanium oxide (), or polyolefin resins such as polyethylene and polypropylene. The average particle size of the fine particles A is preferably 0.1 to 10 μm, and the maximum particle size preferably does not exceed 50 μm. The fine particles A are dispersed and contained in the resin of the present invention so that substantially no particles exceeding 50 μm are present, and then stretched, thereby forming voids around the fine particles A and forming the thermoplastic resin film. It can be made opaque and white. In this case, the average particle diameter of the fine particles A is preferably within the above range from the viewpoint of opacity, whiteness, smoothness, glossiness, etc. Furthermore, even if the average particle size is within the range of 0.1 to 10 μm, it may re-agglomerate in the resin of the present invention to form granules with a size of substantially 50 μm or more. , Glossiness and Mechanical Strength In addition, when a photographic layer is provided, defects such as white spots appear in the photographic image obtained, so of course the maximum particle diameter of fine particles A should not exceed 50 μm. In particular, it is preferable to disperse it in a resin and mold it so that it does not re-agglomerate to form particles exceeding 50 μm. When fine particles A are dispersed in the resin of the present invention and stretched in biaxial directions as described below, voids with fine particles A as cores are generated in the in-plane direction of the film. 1st
The figure shows a model of this void. In the figure, 1 is a fine particle A, 2 is a void, 3 is a white pigment B, which will be described later, and 4 is a resin of the present invention. This figure can be easily seen by observing the film under a microscope, especially an electron microscope or a phase contrast microscope, at a magnification of 500 to 10,000 times. The above-mentioned void means a small space existing between the fine particles A and the resin of the present invention. The white pigment B used in the present invention is titanium oxide (2) whose surface has been treated with an aluminum compound having an oxygen bond or a hydroxyl group bond, such as alumina, and/or a silicon compound such as silicic acid, or which has been further treated with a metal. Examples include titanium oxide surface-treated with soap, surfactants, coupling agents, etc., but fine particles that are white pigments, have strong adhesive strength with the resin of the present invention, and do not substantially create voids when stretching the resin film. Any surface treatment method may be used, and the surface treatment method is not limited to the inorganic compound. In the present invention, the white pigment B compound includes:
Particularly preferred is titanium oxide. This means that the refractive index of titanium oxide (n = 2.5 to 2.75) is higher than the refractive index of the resin of the present invention (for example, PET's refractive index of 1.66).
This is because it has a greater light-reflecting ability and, when used in a support for a photographic material, the resulting photographic image has excellent resolution. As titanium oxide (2), either rutile type, anatase type, or a mixture of both can be used. The average particle size of the white pigment B of the present invention is preferably in the range of 0.1 to 0.5 μm from the viewpoint of light reflection ability as a support, and it is preferable that the maximum particle size does not exceed 50 μm. In the present invention, the white pigment B that is dispersed with substantially no voids in the periphery refers to the white pigment B that is dispersed in the resin of the present invention and stretched biaxially as described below. Even when a film is formed, voids as shown in FIG. 1 are not substantially formed around the white pigment B. As a method for dispersing the fine particles A and the white pigment B of the present invention in the resin of the present invention, the fine particles A and the white pigment B are added to a glycol such as ethylene glycol.
A method of adding and dispersing to form a slurry, and adding the slurry to a polyester-forming precursor,
A method of dispersing the fine particles A and white pigment B of the present invention in a polyester resin using a kneading machine such as a Henschel mixer, a Banbury mixer, a twin-screw kneader, etc., and a method of the present invention during molding of polyester resin chips. fine particles A and white pigment B
The timing and order of addition of the fine particles A and the white pigment B are not particularly limited, and may be added at any time up to film forming. In the present invention, the ratio of the fine particles A to the white pigment B is preferably 0.1 to 1.0, more preferably 0.2 to 0.5, in view of the resolution of the photographic image, the mechanical strength and opacity of the film, and the like. When the above-mentioned fine particles A and white pigment B are dispersed and contained in the resin of the present invention in the above-mentioned addition ratios and molded under the molding conditions described below, the photographic image formed in the photographic layer has good resolution and no defects. A support having good transparency and whiteness (hereinafter referred to as the support of the present invention) can be obtained. The support of the present invention may contain other commonly used white pigments and additives, such as optical brighteners, dyes, ultraviolet absorbers, antistatic agents, etc., as long as they do not impede 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 fine particles A of the present invention and the white pigment B are added is extruded from a slit die after being melted, and is ground on a rapidly cooling surface such as a rotating drum to form an amorphous form. After forming into a sheet, the glass transition temperature of the resin of the present invention T _g or more 130
Stretching can be performed sequentially or biaxially in a uniaxial direction in the longitudinal or transverse directions or simultaneously in a temperature range of .degree. C. or lower. At this time, in order to form voids useful for improving opacity and 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 carry out heat setting and heat relaxation. The film thickness of the support of the present invention is 40 to 300 μm,
Preferably it is 60 to 250 μm. When it is thinner than 40 μm, it is weak as a support and tends to wrinkle easily. Moreover, if it exceeds 300 μm, there will be drawbacks such as being too thick and making it inconvenient to handle. In addition, the total visible light transmittance of the support of the present invention is determined in order to ensure sufficient opacity and whiteness when viewed with the naked eye.
It should be 20% or less, more preferably 10% or less. Therefore, the amount of the fine particles A and the white pigment B to be added is adjusted so that the total visible light transmittance of the support of the present invention is 20% or less, preferably 10% or less at a film thickness of 40 to 300 μm, preferably 60 to 250 μm. Select stretch ratio. A light-sensitive photographic emulsion layer is coated on at least one side of the support of the present invention, which has been shaped as described above and has been rendered opaque and white. In this case, if necessary, a surface activation treatment such as corona discharge and/or a subbing layer can be applied prior to coating the photosensitive photographic emulsion layer. The reflective photographic material of the present invention and its manufacturing method include:
It can be applied to all photographic materials that use a support, for example, there are no restrictions on black and white or color, and even in photographic constituent layers, such as a light-sensitive photographic emulsion layer, an intermediate layer, a protective layer, a filter layer, a back coat layer, etc. There are no particular restrictions on the number of layers or the order of the layers. The photographic emulsion layer in the present invention is a normal silver halide emulsion layer, such as silver chloride, silver bromide,
Silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsions, etc. can be preferably used. 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 sensitized in the photosensitive wavelength range using cyanine dyes, merocyanine dyes, etc., and various other photographic additives such as antifoggants, 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 and the method for producing the same of the present invention, there is no penetration of photographic processing liquid etc. from the cross section of the support, so the preservation of photographic images over time is excellent, and the support Even if the body is made thinner, a reflective photographic material with excellent whiteness, opacity, and gloss, and excellent resolution of photographic images, suitable for viewing and recording purposes, 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 0.74, 8 parts by weight of barium sulfate with an average particle size of 0.6 μm, and 17 parts by weight of rutile titanium oxide () with an average particle size of 0.2 μm surface-treated with alumina was prepared. After melt kneading,
It was extruded from a slit die onto a rapidly cooling rotary drum to form an amorphous sheet with a film thickness of 1.1 mm. This amorphous sheet was stretched 3.0 times in the longitudinal direction at 90°C, then 3.0 times in the transverse direction at 110°C, and further stretched at 220°C.
The photographic film support of the present invention was obtained by heat setting. The film thickness of the obtained photographic film support was 125 μm.
It was hot. In addition, to evaluate the opacity, the total visible light transmittance was measured using a digital turbidimeter model T-2600DA.
(manufactured by Tokyo Denshoku Co., Ltd.). The results are shown in Table 1. The above photographic film support was subjected to corona discharge treatment and subbing treatment, and a gelatin-silver halide color photographic emulsion, which is commonly used in color photographic paper, was coated on the surface to a dry film thickness of 15 μm. ,
Intended reflective photographic material sample 1 was prepared. After printing a dense line chart for resolution measurement on the reflection photographic material sample 1 obtained above and exposing it to light, it was developed in the usual manner, and the optical density difference of the dense line printed image was measured using a microdensitometer PDM-5 (Konishi (manufactured by Rokusha Kogyo Co., Ltd.), and the value expressed by the following formula was defined as the resolution. Dmax of dense line print image with resolution (%) = 5 lines/mm
Density difference of Dmin/Dmax and D of dense line print image of 0.1 lines/mm
min density difference x 100 Also, for the white background area after development, the spectrophotometer
380-780nm measured with Model 320 (manufactured by Hitachi, Ltd.)
Calculate the spectral reflectance of the area according to JIS-Z-8722 (1982) to determine the whiteness (L value), and then measure the reflectance of 20°-20° with a gloss meter using the method of JIS-Z-8741. 4, and the glossiness (%) was measured. The results are also shown in Table 1. Example 2 In the above reflective photographic material sample 1, the photographic film support composition was made of PET resin 100 having an intrinsic viscosity of 0.74.
17 parts by weight of anatase-type titanium oxide with an average particle size of 0.2 μm and surface treated with alumina and silica,
Reflection photographic material sample 2 was prepared in the same manner as in Example 1, except that 8 parts by weight of stretching grade propylene homopolymer was used instead. Example 3 In the reflective photographic material sample 1 of Example 1, the photographic film support composition was composed of 100 parts by weight of PET resin with an intrinsic viscosity of 0.68 and 15 parts by weight of rutile-type titanium oxide surface-treated with alumina and having an average particle size of 0.3 μm. , 10 parts by weight of barium sulfate with an average particle size of 0.3 μm, a blue dye commercially available as Macrolex Blue-RR
Reflection photographic material sample 3 was prepared in the same manner as in Example 1 except that the concentration was changed to 50 ppm. Example 4 In reflective photographic material Sample 1 of Example 1, a photographic film support composition having the same composition as Sample 1 was melted and rapidly cooled in the same manner as in Example 1, and the thickness was
It was made into an amorphous sheet of 1.6 μm. This sheet was stretch-molded in the same manner as in Example 1 to obtain a photographic film support of the present invention having a thickness of 180 μm, and reflective photographic material sample 4 was prepared in the same manner as in Example 1. Example 5 In reflection photographic material Sample 1 of Example 1, a photographic film support composition having the same composition as Sample 1 was melted and rapidly cooled in the same manner as in Example 1, and the thickness was
A 0.9 μm amorphous sheet was produced and stretched in the same manner as in Example 1 to obtain a 100 μm thick photographic film support of the present invention, which was then made into a reflective photographic material in the same manner as in Example 1. Sample 5 was prepared. Comparative Example 1 In reflective photographic material sample 1 of Example 1, the photographic film support composition was composed of 100 parts by weight of PET resin with an intrinsic viscosity of 0.74 and barium sulfate with an average particle size of 0.6 μm.
Example 1 except that the composition was replaced with a composition consisting of 25 parts by weight.
Reflection photographic material sample 6 was prepared in the same manner as described above. Comparative Example 2 In the reflective photographic material sample 1 of Example 1, the photographic film support composition was made of 100 parts by weight of PET resin with an intrinsic viscosity of 0.74, anatase type titanium oxide 25 with an average particle size of 0.2 μm and no surface treatment. Reflection photographic material sample 7 was prepared in the same manner as in Example 1, except that the composition consisted of parts by weight. Comparative Example 3 In the reflective photographic material sample 1 of Example 1, the photographic film support composition was made of 100 parts by weight of PET resin with an intrinsic viscosity of 0.74, anatase type titanium oxide 17 with an average particle size of 0.2 μm and no surface treatment. weight part,
Reflection photographic material sample 8 was prepared in the same manner as in Example 1, except that the composition was replaced with 8 parts by weight of barium sulfate having an average particle diameter of 1.0 μm, and the film thickness was reduced to 50 μm. When the cross sections of the supports of Samples 1 to 5 were observed using an electron microscope at a magnification of 5,000 times, no coarse particles of 20 μm or more were observed, indicating that they all had good dispersibility. Moreover, the support could be stably manufactured without cracking during manufacture. On the other hand, when the cross section of the supports of samples 6 to 8 was observed with an electron microscope at a magnification of 5,000 times, the diameter was 10 to 20 μm.
A large number of particles were observed, and some particles were larger than 50 μm, indicating that the dispersibility was not very good. In addition, the support may crack during manufacture, making stable manufacture difficult. Furthermore, the resulting film also did not have good smoothness. Samples 2 to 8 obtained in Examples 2 to 5 and Comparative Examples 1 to 3 above were exposed and developed in the same manner as Sample 1, and the characteristics of each sample were measured in the same manner. The results are also shown in Table 1. Indicated.

[Table] From Table 1, it can be seen that all of Samples 1 to 5 of the present invention have significantly improved image resolution. Also, the opacity of the support, the whiteness of the reflective photographic material,
The gloss level is also good. On the other hand, Samples 6 and 7 according to Comparative Examples have good opacity of the support and good whiteness as a reflective photographic material, but it can be seen that the resolution of the image is clearly inferior to that of the present invention. In addition, it can be seen that in sample 8, the opacity of the support was not good and the resolution as a reflective photographic material was also poor. In addition, in all of Samples 1 to 8, there was no seepage of the developing processing solution from the cut surface, and the obtained images had good storage stability. As described above, according to the present invention, there is no penetration of photographic processing liquid etc. from the cross section of the support, and even if the support is made thin, it has excellent whiteness, opacity, and gloss, and furthermore, it can provide reflection with excellent resolution of photographic images. Photographic material is obtained.

[Brief explanation of drawings]

The drawing is an explanatory diagram of voids formed in the support film of the reflective photographic material of the present invention. 1...Fine particles A, 2...Void, 3...White pigment B, 4...Film resin.

Claims (1)

[Claims] 1. A polyester containing fine particles A dispersed in a resin with voids around them and white pigment B dispersed in a resin with substantially no voids around them. A reflective photographic material, characterized in that 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 film having a thickness of 40 to 300 μm and a total visible light transmittance of 20% or less. . 2. In a thermoplastic resin whose main component is polyester resin, fine particles A have a weak adhesive force with the thermoplastic resin and are inert to the thermoplastic resin, and white pigment B has a strong adhesive force with the thermoplastic resin. After melting and quenching the resin composition to form an amorphous sheet, the resin composition containing the pigment A is melted and then rapidly cooled to form an amorphous sheet. Stretched to a film thickness of 40~
300 μm and a total visible light transmittance of 20% or less, a white film support is formed, and a light-sensitive photographic emulsion layer is coated on at least one side of the white film support.