JP2892221B2 - Photographic paper support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic paper support, and more particularly to a photographic paper support having high rigidity.

[0002]

2. Description of the Related Art Conventionally, in a photographic printing paper, a polyolefin layer containing kneaded and dispersed titanium oxide has been coated on the emulsion coating side surface of a base paper in order to increase water reflection and light reflection efficiency. I have. Polyolefins have been widely used because of their excellent flexibility and processability. However, they have low flexibility, but have low self-supporting properties and lack rigidity.

In recent years, studies have been made to use polyester instead of conventional polyolefin as a resin for coating the base paper surface in order to obtain a high resolution and better flatness (Japanese Patent Application No. 3-89983).

[0004]

However, there is a problem that the desired rigidity cannot be obtained with polyester alone. An object of the present invention is to provide a photographic printing paper support having high rigidity and excellent self-supportability.

[0005]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A composition obtained by mixing and dispersing particles mainly composed of titanium dioxide in polyester is coated on the emulsion-coated surface of the base paper by melt extrusion lamination, and the composition mainly composed of polyester is coated on the emulsion-coated back surface of the base paper. In the photographic printing paper support thus prepared, talc and / or talc having an average particle diameter of 1.0 μm or less was formed on the coating layer on the emulsion-coated side of the base paper.
Or kaolin, 100 parts by weight of polyester,
This was achieved by including 0.1 to 20 parts by weight.

The polyester in the present invention includes a polycondensate of an aromatic dicarboxylic acid such as polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalene dicarboxylic acid ester and an aliphatic diol, and bisphenol A and 5-sodium sulfo. Copolymers into which a copolymer component such as isophthalic acid is introduced are exemplified. Of these, polyethylene terephthalate is particularly preferred.

As polyethylene terephthalate, in addition to polyethylene terephthalate alone, a mixture of polyethylene terephthalate and another polyester blended at a ratio of 50% by weight or less, or isophthalic acid as a two-base component other than terephthalic acid is used. And, as a glycol component other than ethylene glycol, neopentyl glycol, triethylene glycol, butanediol, using one or more components selected from ethylene oxide adducts of bisphenol A, etc., polyethylene terephthalate component as a main component Also included are copolymers copolymerized as follows. The molecular weight of these polymers is preferably from 30,000 to 50,000.

The resin layer may be a polyester resin alone, but may be a resin layer obtained by mixing another resin with a polyester resin. As other resins, for example, polyethylene, polypropylene, ethylene-propylene copolymer,
Ethylene-vinyl acetate copolymer, polycarbonate, acrylonitrile polymer, polystyrene, vinyl (co)
A wide variety of polymers, polyamides, etc. can be selected. Among these, the case where a polyolefin is used is preferable. The amount of the other resin mixed with the polyester resin is 1% by weight to 20% by weight, preferably 1% by weight to 10% by weight.

The titanium dioxide contained in the coating layer on the emulsion coated side of the base paper may be either an anatase type or a rutile type. When whiteness is prioritized, anatase type titanium dioxide is used, and sharpness is prioritized. In this case, rutile-type titanium dioxide is preferable. The preferred average particle size of the particles is 0.1 to 0.8 μm. When the thickness is 0.1 μm or less, it is difficult to uniformly mix and disperse the resin, which is not preferable.
When the thickness is 0.8 μm or more, sufficient whiteness cannot be obtained, and projections are formed on the coated surface, which adversely affects image quality. Specific product names include KA-10 and KA-20 of Titanium Industry. The content of titanium dioxide with respect to the resin is preferably 2 to 30 parts by weight, and more preferably 5 to 25 parts by weight, based on 100 parts by weight of the polyester.

Next, similarly to titanium dioxide, the talc and / or kaolin contained in the coating layer on the emulsion coating side surface of the base paper preferably has an average particle size of 0.01 μm to 1.0 μm, more preferably 0 μm to 1.0 μm. .1 μm to 0.5 μm. If the average particle size is less than 0.01 μm, it is difficult to disperse.
If it exceeds 0 μm, the surface condition of the surface of the coating layer will be poor.

The amount of the polyester 1
The amount is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, with respect to 00 parts by weight. And titanium dioxide, the amount of powder becomes too large, too hard, and the gloss deteriorates.

The added particles may be either talc or kaolin, but is preferably talc. Other inorganic particles such as CaCO ₃ , BaSO ₄ , ZnO, TiO ₂ , Zn
Compared with S, MgCO ₃ , carbon, etc., the talc or kaolin of the present application is likely to be a nucleating agent for accelerating the crystallization of polyester, has an effect of remarkably increasing the rigidity, and greatly contributes to imparting a rigid feeling.

Titanium dioxide, kaolin or talc is
2 rolls with a dispersing aid such as a metal salt of higher fatty acid, higher fatty acid ethyl, higher fatty acid amide, higher fatty acid, etc.
It is kneaded into the resin by a kneader such as a roll, kneader, and Banbury mixer. An antioxidant can be contained in the resin layer.
m to 1000 ppm can be added.

The thickness of the coating layer coated on the emulsion-coated side of the base paper is preferably from 5 to 50 μm, more preferably from 10 to 50 μm.
30 μm. If the thickness exceeds this range, problems in physical properties such as emphasizing the brittleness of the resin and causing cracks arise. If the ratio is less than the above 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 (backcoat layer) is also coated on the back side of the base paper (the side opposite to the side on which the photosensitive emulsion is coated).
In order to increase the rigidity of the photographic paper support, it is preferable to coat with polyester. This polyester is similar to that described above. This back coat layer
It is provided for antistatic, curl prevention, etc.,
JP-B-52-18020, JP-B-57-9059,
JP-B-57-53940, JP-B-58-56859
JP-A-59-214849, JP-A-58-184
Inorganic antistatic agents or organic antistatic agents described or exemplified in each publication such as No. 144, hydrophilic binder, latex,
A curing agent, a pigment, a surfactant and the like can be appropriately combined and contained.

Coating the base paper on the side other than the emulsion-coated side;
The thickness of the resin is preferably from 5 to 50 μm, more preferably from 10 to 30 μm. When the thickness exceeds this range, the brittleness of the resin is emphasized, and problems such as cracks are caused in physical properties. If the ratio is less than the above 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.

Examples of the method of coating the coating layer on the emulsion-coated side of the base paper and the backside layer include a melt extrusion lamination method.

Examples of the base paper include natural pulp paper containing ordinary natural pulp as a main component, mixed paper made of natural pulp and synthetic fiber, synthetic fiber paper containing synthetic fiber as a main component, and synthetic resin films such as polystyrene and polypropylene. Any of so-called synthetic papers, which are made into pseudo paper, may be used, but natural pulp paper is particularly preferably and advantageously used as a substrate of a photographic printing paper support. Additives include fillers such as clay, talc, calcium carbonate, and urea resin particles in addition to alkyl ketene dimer, sizing agents such as rosin, higher fatty acid salts, paraffin wax and alkenyl succinic acid, and paper strength agents such as polyacrylamide. And a fixing agent such as a sulfuric acid band are added. Other, if necessary, dye,
A fluorescent dye, a slime control agent, an antifoaming agent and the like are added. Further, a softening agent is added as required.

The pulp surface may be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, and modified polyvinyl alcohol. As the modified polyvinyl alcohol in this case,
Examples thereof include a carboxyl group-modified product, a silanol-modified product, and a copolymer with acrylamide. When the surface sizing is performed with the film-forming polymer, the coating amount of the film-forming polymer is 0.1 g / m ^{2 to} 5.0 g / m ² , preferably 0.5 g / m ^{2 to} 2.0 g / m ^2. It is adjusted to.
Further, an antistatic agent, a fluorescent whitening agent, a pigment, an antifoaming agent, and the like can be added to the film-forming polymer at this time, if necessary.

The base paper is prepared by using a pulp slurry containing the above-mentioned pulp and additives such as fillers, sizing agents, paper-strengthening agents, and fixing agents, which are added as necessary, with a paper machine such as a fourdrinier paper machine. It is manufactured by papermaking, drying and winding. The surface sizing is performed either before or after the drying, and a calendering is performed after the drying and winding. This calendering treatment can be performed before or after the surface sizing treatment when the surface sizing treatment is performed after drying. However, it is preferable that the calendering treatment be performed in the final finishing step in which various treatments are performed. . In the calendering process, known metal rolls and elastic rolls used for ordinary paper production are used. The base paper is subjected to the above-described calendering process, and is finally adjusted to a film thickness of 50 μm to 250 μm. The density of the base paper ^{0.8g / cm 3 ~1.3g / cm 3} , preferably from ^{1.0g / cm 3 ~1.2g / cm 3} .

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

[0022]

The coating layer on the emulsion coated side of the base paper contains talc and / or kaolin together with titanium dioxide. Talc and / or kaolin tend to be a nucleating agent for accelerating the crystallization of polyester. It is thought to have the effect of increasing the rigidity and greatly contribute to the imparting of a sense of rigidity.In addition, by forming the coating layer on the back side of the base paper emulsion coating side with polyester resin, not only water resistance but also excellent stiffness It can be used as a photographic paper support.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[0024]

EXAMPLE On a surface of a base paper having a thickness of 125 μm, 10 parts by weight of titanium dioxide (particle diameter: 0.3 μm), 100 parts by weight of polyethylene terephthalate, talc, kaolin,
Barium sulfate is also polyethylene terephthalate 10
0 parts by weight, mixed with polyethylene terephthalate at the ratio shown in Table 1, and melt-extruded at 300 ° C.
A 30 μm thick laminate layer was formed.

On the back surface, polyethylene terephthalate was melt-extruded at 300 ° C. to form a 30 μm-thick laminate layer. In addition, the sample for the comparative example using polyethylene was also produced.

The prepared samples were evaluated as follows.

(1) Rigidity As shown in FIG. 1, a photographic printing paper support 1 having a width of 1.5 cm is fixed to a fixing jig 2 with the upper portion of the photographic printing paper support remaining 1.0 cm. 4mm on top of support
The force applied when moving was measured. Table 1 shows the results.

(2) Gloss The reflection gloss at 60 degrees was measured and evaluated using a handy gloss meter HG246 (trade name, manufactured by Suga Test Instruments Co., Ltd.). Table 1 shows the results. In the table, PE represents polyethylene and PET represents polyethylene terephthalate.

[0029]

[Table 1]

^{1) The} added powder refers to talc, kaolin, barium sulfate.

[0031]

[Table 2]

^{1) The} added powder refers to talc, kaolin, barium sulfate.

[Brief description of the drawings]

FIG. 1 is a schematic view of a stiffness measuring device for a photographic printing paper support, wherein (a) is a side view and (b) is a front view.

[Explanation of symbols]

 Reference numeral 1 denotes a photographic printing paper support, and 2 denotes a fixing jig.

Continuation of front page (56) References JP-A-1-177536 (JP, A) JP-A-49-99021 (JP, A) JP-A-63-103234 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) G03C 1/79 D21H 27/36 G03C 1/95

Claims (1)

(57) [Claims] 1. A composition in which particles containing titanium dioxide as a main component are mixed and dispersed in a polyester, and the surface of the base paper on which the emulsion is applied is coated by melt extrusion lamination on the emulsion-coated side of the base paper. In the photographic printing paper support coated with the composition to be coated, talc and / or kaolin having an average particle diameter of 1.0 μm or less are added to the coating layer on the emulsion coating side surface of the base paper in an amount of 0.1% to 100% by weight of the polyester. A support for photographic printing paper, comprising 1 to 20 parts by weight.