JP2832118B2 - 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 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, 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. Although polyolefins have excellent flexibility and processability, they have been widely used. In recent years, studies have been made to replace the polyolefins with resins having higher strength (such as polyester) (Japanese Patent Application No. 3-8).
9983).

[0003]

However, polyethylene terephthalate, which is the most frequently used polyester, has high mechanical strength compared to polyethylene and has many advantages such as being thin and having high rigidity, but has a melting point of polyolefin. , The adhesive strength tends to be low when laminating on base paper by melt extrusion. In particular, poor adhesion on the emulsion-coated surface side may lead to troubles such as peeling when processing is finally carried out as photographic paper and seepage of a processing solution, and the problem remains.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photographic printing paper support having excellent flatness and excellent adhesion between a base paper and a resin coating layer.

[0005]

According to the present invention, there is provided a support for photographic printing paper, wherein a composition in which a white pigment is mixed and dispersed in a polyester resin comprising a dicarboxylic acid component and a diol component is coated on the emulsion-coated surface of the base paper. The polyester resin is characterized in that the dicarboxylic acid component is a mixture of terephthalic acid and naphthalenedicarboxylic acid (molar ratio: 9: 1 to 2: 8).

[0006] The polyester resin in the present invention comprises a dicarboxylic acid component and a diol component, and the dicarboxylic acid component comprises a mixture of terephthalic acid and naphthalenedicarboxylic acid. When the mixing ratio (molar ratio) of terephthalic acid and naphthalenedicarboxylic acid was 9: 1 to 2: 8, it was found that both the glossiness and the adhesion were excellent.

As naphthalenedicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-3,7-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene-2,8-dicarboxylic acid can be used. ,
Particularly, naphthalene-2,6-dicarboxylic acid is preferred.

[0008] Examples of the diol include ethylene glycol, butylene glycol, neopentyl glycol, 1,4-dihydroxymethylcyclohexane, and polyethylene glycol having a molecular weight of 400 to 4000. Among these, when ethylene glycol or a mixed diol containing ethylene glycol is used, the adhesiveness to the base paper is excellent.

Further, the intrinsic viscosity of the polyester resin is 5.
5 to 7.5 dl / g (25 ° C.), more preferably 5.8
-7.2 dl / g (25 ° C.) and excellent adhesion.

Next, a method for producing the polyester according to the present invention will be described. The polyester used in the present invention may be one produced by a continuous method or a batch method, and may be one produced by a transesterification reaction or a direct esterification reaction. Examples are given below, but the polyester in the present invention is not limited thereto.

17.5 kg (90.3 mol) of dimethyl terephthalate and 2.5 kg (10.2 mol)
Dimethyl ester of naphthalene-2,6-dicarboxylic acid and 14.3 kg (231 mol) of ethylene glycol were charged into a reaction vessel equipped with a stirrer, a nitrogen gas inlet tube and a rectification column, and manganese acetate was further used as a transesterification catalyst. Is added in an amount of 100 ppm as manganese metal, and heated to 200 ° C. While removing methanol generated by the reaction from the rectification column, the mixture was heated for 1 hour, and further heated for 22 hours.
The temperature is raised to 5 ° C. for 1 hour and then to 250 ° C. When the theoretical amount of methanol has flowed out, the transesterification reaction is terminated.

The reaction-terminated liquid is transferred to a polycondensation reaction tank heated to 290 ° C., and an antimony trioxide as an antimony metal is added in an amount of 200 ppm as antimony metal as a polycondensation reaction catalyst.
The degree of vacuum in the reaction system was increased to 1.5 Torr. The end point of the polycondensation reaction may be determined by the torque value of the stirrer, but the reaction was allowed to proceed for 3 hours. The intrinsic viscosity of the obtained polyester is 6.8 dl / g (25 ° C.), and the yield is 98.
%Met.

When the polycondensation reaction was completed, the inside of the reaction system was pressurized to about 1 kg / cm ² with nitrogen pressure, the polymer was drawn out from the bottom of the kettle in the form of a strand, and cut into pellets while cooling with water.

As the white pigment to be added to the polyester resin, powders of titanium dioxide, barium sulfate, zinc oxide, talc, calcium carbonate, aluminum oxide, silicon oxide, etc., and solid solutions thereof can also be used. Preferred among the pigments are titanium dioxide and barium sulfate.
The pigment generally has a particle size of 0.1 to 0.8 μm. If it is less than 0.1 μm, it is difficult to uniformly mix and disperse the pigment in the resin, which is not preferable. 0.8 μm
If it exceeds, sufficient whiteness cannot be obtained, and a special note is generated on the coated surface, which adversely affects the image quality.

As titanium dioxide, either anatase type or rutile type may be used, but anatase type titanium dioxide is preferred when whiteness is prioritized, and rutile type titanium dioxide is preferable when sharpness is prioritized. Specific product names include KA-10 and KA-20 of Titanium Industry.
Titanium dioxide is kneaded with a dispersing agent such as a metal salt of a higher fatty acid, a higher fatty acid ethyl, a higher fatty acid amide, or a higher fatty acid into a resin by 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 thereof may be 50 ppm to 1000 ppm based on the resin.

The content of the pigment in the polyester layer is 2
% To 50% by weight, preferably 5% to 30% by weight
It is good to When the polyester layer has a multilayer structure, it is preferable to provide a concentration gradient such that the concentration of the pigment in the coating layer is low in the resin layer on the base paper side and high in the outermost layer. The outermost layer in the coating layer furthest 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,
Preferably it is 15% by weight or more, but if it exceeds 50% by weight, cracking occurs, which is not practical. The layers other than the outermost layer may have a small amount of pigment, and the content is 10% by weight or less, preferably 7% by weight or less.

Examples of the method of coating the polyester layer include a melt extrusion lamination method and the like.
5 to 50 μm is preferable, and more preferably 10 to 30 μm
m. 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 (back coat 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).
As the resin layer, any resin that can be extruded and formed by solvent dissolution molding can be used. For example, polyesters such as polyethylene terephthalate, polyethylene,
Examples include polypropylene, nylon, polystyrene, polyvinyl alcohol, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylonitrile resin, polyacrylates, epoxy resin, and polyether ketone.

This back coat layer is provided for the purpose of preventing static electricity and curling, etc.
No. 020, JP-B-57-9059, JP-B-57-53
940, JP-B-58-56859, JP-A-59-2
No. 14849, JP-A-58-184144 and the like, or an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant and the like described or exemplified as appropriate. be able to.

As a method for coating the backside layer, a melt extrusion lamination method or the like can be mentioned.
m is preferable, and more preferably, 10 to 30 μm.
When the thickness exceeds this range, the brittleness of the resin is emphasized,
Problems such as cracking occur 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.

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 photographic printing paper support of the present invention can ensure the smoothness of the surface and the excellent adhesion while keeping the water resistance and the whiteness equivalent to those of the conventional one. A photographic printing paper support having durability against peeling can be obtained.

Now, the present invention will be described in further detail with reference to Examples.

[0024]

【Example】

(Examples 1-4 and Comparative Examples 1-2) Polyester having a dicarboxylic acid composition shown in the following Table 1 was used as a resin component on the surface of a base paper having a thickness of 180 µm, and titanium dioxide [KA-10 manufactured by Titanium Industry Co., Ltd.] ) Were melt-extruded and laminated at 300 ° C. to form a coating layer having a thickness of 30 μm.

On the other hand, a polyethylene terephthalate resin is melt-extruded and laminated at 300 ° C. on the back of the base paper.
A coating layer having a thickness of 30 μm was formed.

For each of the obtained photographic printing paper supports,
The glossiness of the emulsion coating side surface was measured using a Suga Handy Gloss Meter HG246, and the adhesion between the coating layer and the base paper was determined by measuring the support of each photographic printing paper by 1.5 cm. Cut to width, and as shown in FIG. 1, 180 of the coating layer 2 from the photographic printing paper support 1.
° Peel strength was measured using a tensile tester Strograph (manufactured by Toyo Seiki Seisaku-sho, Ltd.).

[0027]

[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 the drawings]

FIG. 1 is a view 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 photographic paper support, 2 is a coating layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshimitsu Okutsu, Fuji Photo Film Co., Ltd. 200, Onakasato, Fujinomiya City, Shizuoka Prefecture (72) Inventor Sugihiko Tada 200, Fuji Photo Film Co., Ltd. (56) References JP-A-3-64600 (JP, A) JP-A-1-177536 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB name) G03C 1/775 G03C 1 / 79

Claims (2)

(57) [Claims] 1. A photographic printing paper support comprising a composition in which a white pigment is mixed and dispersed in a polyester resin comprising a dicarboxylic acid component and a diol component, and coated on the emulsion-coated surface of a base paper, wherein the polyester resin comprises: A support for photographic printing paper, wherein the dicarboxylic acid component is a mixture of terephthalic acid and naphthalenedicarboxylic acid (molar ratio: 9: 1 to 2: 8). 2. The photographic printing paper support according to claim 1, wherein the diol component is ethylene glycol.