JPH06123934A - Supporting body for photographic printing paper - Google Patents

Abstract

PURPOSE:To obtain a supporting body for photographic printing paper excellent in flatness and adhesive strength to original paper and a resin coating layer by using a mixture of terephthalic acid with isophthalic acid as a dicarboxylic acid component in a polyester resin. CONSTITUTION:The supporting body 1 for photographic printing paper made by applying a composition 2 made by mixing to disperse a white pigment in the polyester resin composed of the dicarboxylic acid component and a diol component on the an emulsion-coated surface of the original paper, the dicarboxylic acid component in the polyester resin is the mixture of terephthalic acid with isophthalic acid ((9:1)-(2:8) molar ratio). Though the diol can be optionally selected, e.g. ethylene glycol, butylene glycol, 2-bis(4-(2-hydroxyethyloxy) phenyl)propane, or cyclohexane dimethanol, etc., is used. Particularly, by using ethyleneglycol or a mixed diol containing ethyleneglycol, the excellent adhesive strength to the original paper is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing paper support, and more particularly to a photographic printing paper support having excellent flatness and excellent adhesion between a base paper and a resin coating layer.

[0002]

2. Description of the Related Art Conventionally, a photographic printing paper is coated with a polyolefin layer containing titanium oxide kneaded and dispersed in the emulsion-coated surface of a base paper in order to improve water resistance and light reflection efficiency. There is. Polyolefin has been used widely because of its excellent flexibility and processability, but in recent years, a study has been made to replace this polyolefin with a resin having higher strength (polyester, etc.) (Japanese Patent Application No. 3-8).
9983).

[0003]

However, polyethylene terephthalate, which is the most frequently used polyester, has many advantages such as higher mechanical strength than polyethylene and is thin and highly rigid, but has a melting point of polyolefin. Since it is higher than that of, the adhesive force tends to be low when laminated on the base paper by melt extrusion. In particular, the low adhesiveness on the emulsion-coated surface side may lead to peeling during development processing as photographic printing paper, leading to troubles such as bleeding of the processing liquid, and thus a problem remains.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a support for photographic printing paper, which has excellent flatness and excellent adhesion between the base paper and the resin coating layer.

[0005]

The support for photographic printing paper of the present invention comprises a composition in which a white pigment is mixed and dispersed in a polyester resin composed of a dicarboxylic acid component and a diol component, on the emulsion-coated surface of the base paper. In the support for photographic printing paper as described above, the polyester resin is characterized in that the dicarboxylic acid component is a mixture of terephthalic acid and isophthalic acid (molar ratio 9: 1 to 2: 8).

The polyester in the present invention comprises a dicarboxylic acid component and a diol component, and the dicarboxylic acid component is a mixture of terephthalic acid and isophthalic acid in a weight ratio of 9: 1 to 2: 8. In the present invention, the terephthalic acid component in the polyester is 20% by weight.
It was found that both the glossiness and the adhesive strength were excellent when the content was within the range of up to 90% by weight.

The diol can be appropriately selected, and examples thereof include ethylene glycol, butylene glycol, 2-bis [4- (2-hydroxyethyloxy) phenyl] propane and cyclohexanedimethanol. Of these, the use of ethylene glycol or a mixed diol containing ethylene glycol provides excellent adhesion to the base paper.

Polyester has an intrinsic viscosity of 5.5 to 7.
5 dl / g (25 ° C.), more preferably 5.8 to 7.2
It is preferable to use dl / g (25 ° C.).

White pigments added to the polyester layer include titanium dioxide, barium sulfate, zinc oxide, talc,
Powders of calcium carbonate, aluminum oxide, silicon oxide and the like, solid solutions thereof, and the like can also be used. Among the pigments, titanium dioxide and barium sulfate are preferable. The particle size of the pigment is usually 0.1 to 0.8 μm. When it is less than 0.1 μm, it is difficult to uniformly mix and disperse the pigment in the resin, which is not preferable. On the other hand, if it exceeds 0.8 μm, sufficient whiteness cannot be obtained, and a special note occurs on the coated surface, which adversely affects the image quality.

Titanium dioxide may be either anatase type or rutile type, but anatase type titanium dioxide is preferred when whiteness is prioritized, and rutile type titanium dioxide is preferred when sharpness is prioritized. Specific product names include KA-10 and KA-20 manufactured by Titanium Industry.
Titanium dioxide is kneaded into a resin together with a dispersion aid such as a metal salt of higher fatty acid, higher fatty acid ethyl, higher fatty acid amide, and higher fatty acid with a kneader such as a two-roll, three-roll, kneader or Banbury mixer. An antioxidant may be contained in the resin layer, and the content may be 50 ppm to 1000 ppm with respect to the resin.

The content of the pigment in the polyester layer is 2
Wt% to 50 wt%, preferably 5 wt% to 30 wt%
It is good to Further, when the polyester layer is multilayered, it is preferable to provide a concentration gradient such that the pigment content concentration in the coating layer is low in the resin layer on the base paper side and high in the outermost layer. The outermost layer of the coating layer farthest from the emulsion-coated surface is an important layer that determines the resolution of the photograph, and the highest pigment concentration increases the resolution of the photograph. The pigment concentration in the outermost layer is 10% by weight or more,
The content is preferably 15% by weight or more, but if it exceeds 50% by weight, cracking occurs, which is not practical. Layers other than the outermost layer may contain a small amount of pigment, and the content is 10% by weight or less, preferably 7% by weight or less.

Examples of the method for coating the polyester layer include melt extrusion lamination method, and the film thickness is
5 to 50 μm is preferable, more preferably 10 to 30 μm
m. If the thickness exceeds this range, the brittleness of the resin is emphasized, causing problems such as cracking and other physical properties. If it is less than this range, the waterproof property which is the original purpose of the coating is impaired and the physical properties become too soft, which is not preferable.

A resin layer (back coat layer) is also coated on the back surface of the base paper (the side opposite to the side coated with the photosensitive emulsion).
The resin layer can be widely used as long as it is a resin that can be extruded and dissolved by solvent. For example, polyesters such as polyethylene terephthalate, polyethylene,
Examples thereof include polypropylene, nylon, polystyrene, polyvinyl alcohol, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylonitrile resin, polyacrylic acid esters, epoxy resin and polyether ketone.

This back coat layer is provided for the purpose of preventing electrification, curling, etc., and is described in JP-B-52-18.
No. 020, Japanese Patent Publication No. 57-9059, Japanese Patent Publication No. 57-53
940, Japanese Patent Publication No. 58-56859, and Japanese Patent Laid-Open No. 59-2.
Inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants and the like described or exemplified in JP-A No. 14849, JP-A-58-184144 and the like are contained in appropriate combination. be able to.

Examples of the method for coating the back surface layer include a melt extrusion lamination method and the like, and the film thickness is 5 to 50 μm.
m is preferable, and more preferably 10 to 30 μm.
When the thickness exceeds this range, the brittleness of the resin is emphasized,
Problems with physical properties such as cracking appear. If it is less than this range, the waterproof property which is the original purpose of the coating is impaired and the physical properties become too soft, which is not preferable.

As a support for photographic photographic paper, various photographic constituent layers are coated, for color photographic photographic paper, for black-and-white photographic photographic paper, for typesetting photographic paper, for photographic photographic paper, for reverse photographic materials,
Silver salt diffusion transfer method Used for various purposes such as negative and positive printing, printing materials, etc., provided with silver chloride, silver bromide, silver chlorobromide, silver iodobromide, and silver chloroiodobromide emulsion layers. The silver halide photographic emulsion layer contains a color coupler,
It is considered as a multilayer silver halide color photographic constituent layer. Further, a silver salt diffusion transfer image receiving layer containing a physical phenomenon nucleus is provided.

[0017]

In the support for photographic printing paper of the present invention, the dicarboxylic acid component is a mixture of terephthalic acid and isophthalic acid (molar ratio 9: 1) as a coating layer on the surface of the raw paper.
By using the polyester resin of (2: 8) as a resin component, the surface smoothness can be secured and the adhesiveness can be excellent while maintaining the water resistance and the whiteness equivalent to those of the conventional one. And a durable photographic paper support.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0019]

【Example】

(Examples 1 to 4 and Comparative Examples 1 and 2) The surface of a base paper having a thickness of 180 μm has the dicarboxylic acid composition shown in Table 1, contains ethylene glycol as a diol component, and further has the intrinsic viscosity shown in Table 1. A resin composition containing 20 wt% of titanium dioxide [KA-10 manufactured by Titanium Industry Co., Ltd.] as a resin component was melt-extruded and laminated at 300 ° C. to form a coating layer having a thickness of 30 μm. . On the other hand, the same resin as above was used as the resin component on the back surface of the base paper, and calcium carbonate (average particle size 1.0 μm)
The resin composition containing wt% was melt-extruded and laminated at 300 ° C. to form a coating layer having a film thickness of 30 μm.

Regarding each of the obtained supports for photographic printing papers,
The flatness of the emulsion-coated surface was measured using a Suga Handy Gloss Meter HG246, and the adhesiveness between the coating layer and the base paper was 1.5 cm for each photographic paper support. Cut out to a width of 180 mm of the covering layer 2 from the photographic paper support 1 as shown in FIG.
The peel strength was measured using a tensile tester Strograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.).

[0021]

[Table 1]

As can be seen from this table, the photographic printing paper support of the present invention is excellent in both glossiness and adhesion.

[Brief description of drawings]

FIG. 1 is a diagram showing a method for measuring the adhesion of a coating layer to a base paper in a photographic printing paper support of the present invention.

[Explanation of symbols]

 1 is a support for photographic printing paper, 2 is a coating layer

Claims (2)

[Claims] 1. A photographic printing paper support comprising a base paper coated with a composition prepared by mixing and dispersing a white pigment in a polyester resin comprising a dicarboxylic acid component and a diol component, wherein the polyester resin comprises: A support for photographic printing paper, wherein the dicarboxylic acid component is a mixture of terephthalic acid and isophthalic acid (molar ratio 9: 1 to 2: 8). 2. The support for photographic printing paper according to claim 1, wherein the diol component is ethylene glycol.