JPS6135442A - Photographic printing paper - Google Patents

Abstract

PURPOSE:To obtain a superior surface smoothness by using a polymer coated paper having an average surface 3-dimensional roughness of a specified value of lower as a support. CONSTITUTION:One side of a paper is coated with a film of a polymer, such as polyethylene or other polyolefine, having an average 3-dimensional roughness of <=4mum to obtain the support of a photographic printing paper. The polyethylene- coated paper is generally prepared by casting molten polyethylene on the surface of a traveling paper. Said average roughness is dependent on the compsn. of the pulp of the paper layer, and the optimum pulp compsn. ratio of needle-leaved wood to broad-leaved wood is in the range of 30:70-90:10, thus permitting a photographic printing paper using a resin-coated paper superior in surface smoothness as a support to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographic paper, and more particularly to a photographic paper with improved coating unevenness of a light-sensitive emulsion layer.

(Prior art) In general, photographic paper uses baryta paper as a support, and uses a photographic paper coated with a photosensitive emulsion on the support, and a waterproof support coated with polyethylene on both sides of the paper. Photographic paper coated with a photosensitive emulsion was known, but recently it has become suitable for rapid processing, and
Photographic paper using polyethylene-coated paper as a support has become commercially available mainly because it does not require an erotic type finish.

By the way, when manufacturing photographic paper using such polyethylene-coated paper as a support, 'mott' is often applied during emulsion coating.
This may cause coating unevenness called "le", which may cause quality problems.

Regarding the improvement of the above-mentioned polyethylene-coated paper support, for example, Japanese Patent Application Laid-Open No. 58-37642 discloses a paper support coated with polyethylene on both sides of paper whose surface smoothness is 95 seconds or more as measured by a Peck smoothness meter. A support for photographic paper is described, and in JP-A-58-68037, the residual content of 42 mesh screen in the fiber length distribution was measured using a fiber sieve machine and was found to be 20% by weight or more when placed in 45 layers. A support for photographic paper is described in which the paper is made of pulp fibers and is coated on both sides with polyethylene.

However, all of these only disclose the smoothness of the support itself or its correlation with gloss, and there is currently a strong demand for prevention of uneven coating by improving the support. be.

(Problems to be Solved by the Invention) It is an object of the present invention to provide a photographic printing paper with improved coating unevenness. The purpose of this invention is to provide photographic paper with the following characteristics.

(Means for Solving the Problems) According to the present invention, the above-mentioned problem of the present invention is achieved in photographic printing paper having a support coated with a coating made of a polymer substance on at least one side of the base paper. It has been found that this problem can be solved by using a photographic paper coated with a polymeric material whose support surface has an average three-dimensional roughness of 4 μm or less.

In the following, the invention will be described in further detail.

The present invention relates to a photographic paper coated with a polymeric material whose surface has an average three-dimensional roughness of 4 μm or less. Roughness means measured according to the definition below.

That is, a part of area S is extracted from the roughness curved surface on its center plane, and orthogonal coordinate axes are set on the center plane of this extracted part.
When the X-axis and Y-axis are placed and the axes orthogonal to the center plane are represented by two axes, the amount defined by the following equation will be referred to as average three-dimensional roughness.

However, s=x, xyl The above analysis is possible by using, for example, a surface roughness analyzer 5E-3AK manufactured by Koita Research Institute.According to the present invention, the above-defined average The problems of the present invention could be solved by a photographic paper in which a polymer material having a three-dimensional roughness (5Ra) of 4 μm or less, such as polyethylene-coated paper, is used as a support.

Photographic stamp ii according to the present invention! The paper coated with a polymeric substance, which is the support of the paper ii, is not limited to the above-mentioned polyethylene coated paper, but any paper coated with polyolefin can be widely used.

The above-mentioned polymer-coated paper used in the present invention, such as polyethylene-coated paper, is generally manufactured by a method in which polyethylene molten at a high temperature is cast onto the surface of the running paper.

According to the present invention, the present invention was made based on the discovery that the pulp composition of the paper waste coated with polyethylene on both sides of the above-mentioned υ' paper is related to the average three-dimensional roughness of the polyethylene-coated paper. Specifically, the pulp composition ratio of the paper layer, softwood: hardwood, is in the range of 30:70 to 90:10, preferably in the range of 40:60 to 80:20, which is the average three-dimensional roughness according to the present invention. It is most suitable for obtaining a thickness of 4 μm or less.

Therefore, in the present invention, a polyethylene-coated paper is prepared by the method described above using paper having a pulp composition ratio of paper waste in the axillary portion within the above-mentioned range, and this is used as a support for, for example, a multilayer slide hopper. Photographic paper can be obtained by coating a photosensitive emulsion using a photosensitive emulsion.

51 The photographic paper according to the present invention has at least one silver halide emulsion layer on one side of the support coated with the above-mentioned polymeric substance, and the above-mentioned silver halide emulsion layer The layer mainly contains gelatin as a binder, photosensitive silver halide, chemical sensitizer, spectral sensitizer, antifoggant, contrast enhancer, gelatin hardener, surfactant, film property improver, thickener, etc. It consists of a photosensitive layer containing .

The photosensitive silver halide in the silver halide emulsion layer is, for example, silver chloride, silver bromide, silver iodide, silver chlorobromide, silver iodobromide, silver chloroiodobromide, etc. Silver halide emulsions are prepared, for example, by the following known method. That is, it may be a conversion emulsion, Lippmann emulsion, covered grain emulsion, or one that has been optically or chemically fogged in advance, and this is selected as appropriate depending on the type of photographic paper and its use. . These photosensitive silver halides can be chemically sensitized using activated gelatin, a sulfur sensitizer, a reduction sensitizer, a noble metal sensitizer, etc. alone or in appropriate combinations. These chemical sensitizers include sulfur sensitizers such as allylthiocarbamide, thiourea, cystine, hypo, etc., and reduction sensitizers such as tin salt, polyamine, hydrogen, etc., and noble metals. As sensitizers, various gold sensitizers, ruthenium, rhodium,
Sensitizers include water-soluble salts such as iridium and palladium.

Furthermore, this silver halide can be optically sensitized to a desired wavelength range, such as optical sensitization of cyanine dyes, styryl dyes, hemicyanine dyes, triphenylmethane dyes, xanthine dyes, oxonol dyes, merocyanine dyes, etc. Optical sensitization can be achieved by using agents alone or in combination (for example, supersensitization).

As mentioned above, a photosensitive layer is formed by dispersing photosensitive silver halide in a binder such as a suitable hydrophilic colloid. Used in the layer structure of various photographic components such as layers. Gelatin is the most desirable hydrophilic colloid, but other hydrophilic colloids may be used, such as derivative gelatin, colloidal albumin, agar, gum arabic, alginic acid, cellulose derivatives, acrylamide, imidized polyacrylamide, casein, polyvinyl alcohol, polyvinylpyrrolidone, and hydrated colloid. It can also be used in combination with polymers such as decomposed polyvinyl acetate.

In addition, for the purpose of improving the physical properties of the photo-Xi layer made of the hydrophilic colloid, various film property improving agents,
For example, a hardening agent can be used.

If such a hardening agent is used in combination, the mechanical strength of the film and its resistance to dissolution in processing liquids will be improved without impairing the interlayer adhesion, making it possible to obtain photographic paper with extremely good film properties. .

When gelatin is used as the hydrophilic colloid, specific examples of typical hardening agents include aldehyde, epoxy, ethyleneimine, active halogen, vinyl sulfone, isocyanate, sulfonic acid ester, and carbodiimide hardeners. Examples include various hardeners such as those based on hardening agents, mucochloric acid-based, acyloyl-based, and the like. Not limited to the above hardening agents,
In the present invention, a wide variety of organic or inorganic gelatin hardeners can be added alone or in combination, and these hardeners are described in "The Theory of Photography" by T. H. James.・Purses” spear 3rd edition (
(1966) and JP-A-53-70426.

Furthermore, in order to make the above-mentioned layer-forming binder flexible in order to prevent dimensional changes and bending due to fluctuations in temperature and humidity, methods of incorporating various polymer latexes into the binder are widely used among those skilled in the art. It can also be contained in the silver halide emulsion layer in the present invention. These various polymer latexes are described, for example, in U.S. Pat.
No. 6,005, No. 2,763,625, No. 2,7
72,166, 2,8 s 2,386, 2,85 '3,457 and 3,397,98
Details are given in No. 8.

Further, a surfactant can be used as a coating aid in the hydrophilic colloid layer of the photographic paper according to the present invention. In addition to natural surfactants such as saponin, these surfactants include cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants. Higher alkylamines as surfactants,
Quaternary ammonium salts, heterocycles such as pyridine, phosphoniums, or sulfoniums; anionic surfactants such as carboxylic acids, sulfo/acids; phosphoric acids, sulfuric esters, phosphate esters; amphoteric surfactants such as amino acids; Known are aminosulfonic acids, sulfuric acid esters of amino alcohols, and nonionic ones such as alkylene oxides, glycerin, and glycidol.

These surfactants can be used alone or in combination, and have not only an effect as a coating aid but also an emulsifying and dispersing effect and an antistatic effect.

The photographic paper according to the present invention has a protective film on the outer surface layer of a photosensitive silver halide emulsion having the above-mentioned constituent elements.

The above protective layer is a layer containing a hydrophilic colloid such as gelatin as a binder, and contains a thickener, a gelatin hardener,
Various additives such as surfactants, ultraviolet absorbers, and antistatic agents can be contained.

When the photographic paper according to the present invention is a color photographic paper, the layer structure may be formed by the usual subtractive color method, and in principle:
A yellow coupler to form a yellow dye in the blue-sensitive photosensitive layer, a magenta coupler to form a magenta dye in the green-sensitive photosensitive layer, and a cyan coupler to form a cyan dye in the red-sensitive photosensitive layer. The basic "layer structure" consists of three layers, each containing . Photographic characteristics such as color reproducibility and granularity of color pigments are described.
The present invention is not limited to these.

Example 1 The following five types of polyethylene-coated papers were prepared, each of which had different pulp compositions on both sides of paper waste coated with polyethylene. This coated paper was obtained by laminating polyethylene with a density of 0.929/cc 1 and a melt index of 309710 on both sides of the paper.

Support (4) Paper layer pulp composition ratio, softwood: hardwood = O: 100 Support 03) Paper layer pulp composition ratio, softwood: hardwood - 20:80 Support 0 Paper layer pulp composition ratio, softwood: hardwood - 40: 60 Support (b) Waste paper pulp composition ratio, softwood: hardwood = 60:40
Support (G) Waste paper pulp composition ratio, softwood: hardwood - 80: 20 The surface of each of the above laminated papers was measured with a surface roughness meter (SR-3AK) manufactured by Koita Research Institute, and the average three-dimensional roughness was determined. When SRa was determined, the following values were obtained.

Support (A) 8 Ra...7.4μ support) SRa...6.1μ support (C)
S Ra...3.8μ support (D)
SRa...3.0μ support (g) SRa
...2.4μ The following photographic constituent layers were coated onto these laminated paper supports using a multilayer slide hopper. (From the support side) 1 layer...Blue-sensitive silver halide emulsion layer A silver chlorobromide emulsion (containing 90 mol% silver bromide) containing 7% gelatin is sensitized to blue light. Optically sensitized using a sensitive dye,
Furthermore, after chemical sensitization using a gold-sulfur sensitizer according to a conventional method, 4-hydroxy-6-methyl-1,3,
An emulsion was prepared by adding 3 g of a 7-titrazaindene compound, a hardening agent, a coating aid, etc., and coated to a dry film thickness of 40 μm.

Two layers: Intermediate layer An intermediate layer containing 6% gelatin was coated to a dry film thickness of 15 μm.

3-layer green-sensitive silver halide emulsion layer A silver chlorobromide emulsion (containing 90 mol% silver bromide) containing 6% gelatin is made using a sensitizing dye that is sensitive to green light. optically sensitized,
Furthermore, after chemical sensitization using a gold-sulfur sensitizer according to a conventional method, 4-hydroxy-6-methyl-1,3,
An emulsion was prepared by adding a 3a, 7-chitrazaindene compound, a hardening agent, a coating aid, etc., and coated to a dry film thickness of 30 μm.

Four layers: Protective layer A protective layer containing 6% gelatin was coated to a dry film thickness of 20 μm.

The coating speed of the photographic constituent layer was 100 crtt/sec. The photographic paper thus obtained was examined for the presence or absence of coating unevenness, and the results shown in Table 1 below were obtained.

As shown in the above table, the supports (C), CD), and (G) according to the present invention, in which the average three-dimensional roughness (8Ra) of the surface of the laminated paper support is 4 μm or less, are all similar to the support for comparison. It can be seen that the uneven coating, that is, the occurrence of mottles, was significantly improved compared to the samples (G) and (B).

Example 2 Polyethylene-coated paper having the following average three-dimensional roughness was prepared by varying the pulp composition constituting the paper layer according to the method of Example 1.

Support (G) Paper layer pulp composition ratio, softwood: hardwood - 33:67 Support paper layer pulp composition ratio, softwood: hardwood = 25:20 The surface of these supports was measured with a surface roughness meter in the same manner as above. The values of the average three-dimensional roughness SRa obtained as a result of the measurement were as follows.

Support (g) SRa...4.4μ support (
G) 8 Ra: 5.5μ Photographic paper was coated on the above polyethylene-coated paper support using a multilayer slide hopper in exactly the same manner as in Example 1, and the presence or absence of coating unevenness was examined. The results are below! It is shown in Table 2.

Table 2 As is clear from the results in the table above, when the average three-dimensional roughness (8Ra) of the surface of the laminated paper support exceeds 4 μm according to the present invention, mo-ttle occurs during coating. It was also found that the occurrence of mottle was minute on the support (g).

(Effect of the invention) It is possible to effectively improve coating unevenness on photographic paper using a paper support coated with a polymeric substance and having a surface average three-dimensional roughness of 4 μm or less. .

Claims (1)

[Claims] In photographic paper having a support coated with a coating made of a polymeric substance on at least one side of the base paper, it is recommended to use a polymeric substance-coated paper in which the average three-dimensional roughness of the surface of the support is 4 μm or less. Characteristic photographic paper.