JPH01274135A - Support for photographic printing paper - Google Patents

Abstract

PURPOSE:To increase surface smoothness by coating both sides of base paper produced by a laminated paper making process with polyolefin. CONSTITUTION:Both sides of base paper produced by a laminated paper making process are coated with polyolefin. The base paper is composed of many layers (2-5 layers), especially 2-3 layers. The resulting polyolefin resin coating layers may be PE layers of 15-40mum thickness and 5-20wt.% titanium oxide is incorporated into the polyolefin resin coating layer on which a photographic emulsion layer is formed. Base paper having high smoothness is obtd. and the surface smoothness of a support can be increased by using the base paper.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a support for photographic paper, and more particularly to a support for photographic paper having a good surface smoothness.

<Prior Art> Currently, photographs with smooth and glossy surfaces are generally preferred.

In this case, the thickness of the photographic emulsion layer is extremely thin, around IOμ, and the smoothness of the surface of the photographic paper is almost the same as that of the support underneath, so the support for the photographic paper has a smooth surface. The body is needed. In order to obtain a photographic paper support with a smooth surface, it is desirable that the base paper constituting the support be smooth. Especially in the case of photographic paper, which is printed without applying 7 erotic types,
Even if the surface of the base paper is coated with polyolefin or the like and a photographic emulsion layer is provided on it, it is difficult to hide the unevenness of the base paper from the surface of the support within the thickness range of the coating layer that is commensurate with cost. Since the smoothness of the surface depends on the smoothness of the base paper, it is considered essential that the base paper be smooth.

Therefore, various proposals have been made to improve the smoothness of the surface of base paper used as a support for photographic paper.

For example, the weight average fiber length measured with a polarized light transmission type fiber length analyzer is in the range of 0.17 Lm to O0, and the number average fiber width measured with a microscope is 13.0 Lm. ! A support for photographic paper (Japanese Patent Application Laid-open No. 60-626≠) using a base paper made of pulp fibers having a number average fiber thickness of ≠μm or more and a number average fiber thickness of ≠μm or less as measured in the cross section of the fibers has been proposed. ing.

<Problems to be Solved by the Invention> However, the use of such fine fibers is disadvantageous in terms of low paper strength and cost.

Therefore, a first object of the present invention is to efficiently provide a base paper with excellent surface smoothness that can be suitably used as a support for photographic paper.

The λ-th object of the present invention is to provide a support for photographic paper that has a smooth surface without the need for ferrotyping.

Means for Solving the Problems> The above objects of the present invention are achieved by a support for photographic paper, which is characterized in that the surface of the base paper is coated with polyolefin, which is produced by a cross-cutting method. Ta.

In the present invention, the laminated paper used as the base paper has multiple layers (
2 to j layers) are combined, and a combination of 2 to 3 layers is particularly preferable. These laminated papers are manufactured by cylinder paper making or fourdrinier paper making.

As the pulp, various natural pulps obtained from coniferous trees, hardwoods, etc. and synthetic pulps are used.

The F fisheries of Nonirupu is /jO to IAOOytl, preferably 200 to 3jOgo.

In addition, this pulp contains clay, Merck, calcium carbonate,
Fillers such as titanium oxide, urea resin fine particles, rosin, alkyl ketene dimer, higher fatty acid salts, paraffin wax, sizing agents such as alkenylconolinic acid, polyacrylamide, melamine resin, boria ξ dopolyamine cibichlorohydrin resin, etc. A fixing agent such as a paper strength agent, sulfuric acid, or a cationic polymer can be added as necessary.

Furthermore, the surface of the pulp can be surface-sized using a film-forming polymer such as gelatin, starch, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, or a modified product of polyvinyl alcohol.

Examples of polyvinyl alcohol modified products in this case include carboxyl modified products, silanol modified products, and copolymers with acrylamide. In addition, when surface size treatment is performed using a film-forming polymer, the coating amount of the film-forming polymer is 0./~j, Og/m, preferably 0.
j~λ, adjusted to Og/rn2. Furthermore, an antistatic agent, a fluorescent whitening agent, a pigment, an antifoaming agent, etc. can be added to the film-forming polymer at this time, if necessary. The base paper used for the photographic support of the present invention is usually made of the above-mentioned pulp, additives, surface treatment agents, etc.
Og/m2 to 2oog/rrL2, thickness 10μ to 2
Sub-aligned to 30μ.

Polyolefin resin M laminated on both sides of this base paper, Enoki 7
For example, l! A polyethylene layer of μ to θμ or the like can be used. The polyolefin resin coating layer on the surface on which the photographic emulsion layer is formed contains titanium oxide in an amount of 20% by weight.

Examples of the above-mentioned polyolefins include homopolymers of α-olefins such as polyethylene and polypropylene, and mixtures of these various polymers. Particularly preferred polyolefins are high density polyethylene, low density polyethylene and mixtures thereof. These polyolefins are usually coated on both sides of the base paper by extrusion coating methods, and therefore there is no particular restriction on their molecular weight as long as they can be extrusion coated, but they usually have a molecular weight in the range of 10-10. Polyolefins are used.

The thickness of the polyolefin coating layer is not particularly limited and can be determined according to the thickness of the polyolefin coating layer of conventional photographic paper supports, but it is usually 70~! Qμm is preferred.

It is preferable that the front surface, that is, the polyolefin plate area I- on the side where the photographic emulsion t-m is applied, contains a white pigment, but the type and amount of this white pigment are among the known ones. It can be selected as appropriate. Furthermore, it is also possible to add known additives such as fluorescent brighteners and antioxidants.

Further, the coplanar polyolefin coating layer can be composed only of the polyolefin resin, but it can also be composed of colored pigments,
A white pigment or the like may be added, and the same additives as those for the polyolefin layer on the front surface may also be added.

As the extrusion coating equipment for extrusion coating polyolefin, a conventional polyolefin extruder and laminator are used.

<Effects of the Invention> According to the invention, since the base paper for the support for photographic printing paper is manufactured by the mixing method, a base paper with a smoothness compared to its basis weight can be obtained and used. As a result, a support for photographic paper with good surface smoothness can be easily obtained.

Furthermore, it is possible to use an inexpensive e-rupe for the lower layer or middle layer of the base paper produced by combining, which is advantageous in terms of cost.

<Examples of the Invention> The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

After mixing 0% by weight of kraft hardwood pulp (LBKP) and 0% by weight of sulfide hardwood pulp (LBSP), the mixture was refined using a disc refiner to give 2zocsF sulfide-processed hardwood pulp. Sodium stearate is 1.5% by weight and polyacrylamide is added to the bone-dried pulp.

A sample was prepared by adding 1% by weight of 3 parts, 0.3% by weight of polyamide boriabane epichlorohydrin, and 0.3% by weight of sulfuric acid bands.

Using this sample, a paper machine was used to make paper having the layer structure and basis weight shown in Tables 1 and 2. Further, as a comparative example, paper (single layer) having the basis weight shown in the third group was made using the same paper stock as above.

Using the same laminator, titanium oxide ioM was applied to the paper A/~A/117 obtained in the above manner on the felt side.
:! lt%, polyethylene is laminated on the wire surface side, and the surface of the polyethylene containing titanium oxide of the support is subjected to corona discharge treatment, and then, from the bottom, a yellow color photographic silver halide gelatin emulsion, a gelatin intermediate layer, A magenta coloring emulsion, a gelatin intermediate layer, a cyan coloring emulsion, and a gelatin protective layer were coated in multiple layers and dried to produce color photographic paper. These were exposed to full color light and developed using an automatic processor to obtain test samples.

The smoothness of the photographic paper screen was visually evaluated and compared and judged according to the following criteria.

Smoothness class A: Extremely smooth with no visible wrinkles.

Smoothness class B: Almost no wrinkle-like unevenness is observed, and the smoothness is good.

Smoothness class C: Some wrinkle-like unevenness is seen, but it is smooth.

Smoothness class D: Many wrinkle-like irregularities are observed and smoothness is poor.

Smoothness class E: There are extremely many wrinkle-like irregularities and the smoothness is poor.

The evaluation results of the smoothness of each sample are shown in Tables 1 to 3.

As shown in Tables 1 to 3, the smoothness decreases as the weight increases, but the photographic paper produced using the support for photographic paper according to the present invention has a basis weight of It can be seen that good smoothness is maintained even when the size increases.

Claims (1)

[Claims] 1. A support for photographic paper, characterized in that the surface of base paper is coated with polyolefin, produced by a paper-combining method.