JPS61262738A - Production for supporting body of photographic paper - Google Patents

Abstract

PURPOSE:To obtain the titled body having a less tendency for generating a coloring and a yellowing of an original, and having a high resolution and gloss by coating a coating solution contg. a specific unsatd. org. compd. and a white pigment on the surface of a substrate followed by irradiating the electron beam to the coated layer, while heating it at a specific temp. range. CONSTITUTION:The unsatd. org. compound capable of polymerizing by the electron beam, and having more than one of carbon-carbon double bonds in a molecule, is comprised an acrylic acid ester, a methacrylic acid ester, an epoxy compd., a diacrylate and a dimethacrylate of an urethane, its ester, a tetracrylate of an epoxy compd. and an epoxy-methacrylate. The unsatd. compd. forms a resin component in the resin layer contg. the white pigment by polymerizing said compd. with the post-treatment of the electron beam irradiation. The inorg. white pigment is comprised a titanium dioxide, a barium sulfate, an antimony trioxide and a titanium phosphate. The weight ratio of the binder component and the white pigment is preferably 3/1-1/9. The thickness of the coating layer is usually 3-100mum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a support for photographic paper, and more particularly to a method for producing a support for photographic paper comprising a paper support. More specifically, the present invention relates to a method for producing a support for photographic paper that has improved resistance to penetration by an aqueous photographic processing solution.

[Conventional technology]

When producing a support for photographic paper having a paper support, it is usually necessary to take some method to prevent water and processing chemicals from penetrating into the paper. Commonly used methods include polymeric barrier layers,
For example, paper is overcoated with a layer of polyolefin, such as polyethylene. In this method, it is preferable to apply a thin layer in order to improve production efficiency and reduce costs, but this requires melting the polyolefin at high temperatures. As a result, there was a drawback that pinholes were formed on the yellowed coated surface. In addition, this method involves foaming during melt extrusion or poor dispersion due to volatile components in the white pigment mixed in to improve hiding power.
It was not possible to increase the content of white pigment, and therefore it was not possible to obtain photographic prints with high resolution.

In recent years, electron beam irradiation has been used to eliminate these drawbacks. Attempts have been made to coat a paper support with a composition containing an organic compound having an unsaturated bond that can be polymerized and a high concentration of an inorganic white pigment, and to cure the composition by electron beam irradiation. <
*Kokai J-7-272!7, JP-A-17-1924t) However, although the above-mentioned drawbacks of the supports obtained by the known methods have been solved, they do not require photographic processing in the developing process. The problem is that chemicals are adsorbed and remain, and the support is colored yellow after development.

In order to solve these problems, electron beam irradiation can be performed at a sufficiently high absorbed dose, but on the other hand, a new problem arises in that the yellowing of the base paper increases and the whiteness of the photographic paper support is impaired. This occurs, making it impossible to obtain a support suitable for use as a support for photographic paper.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a method for producing a support for photographic paper that has high resolution and high gloss and is resistant to coloration and yellowing of the base paper during development.

[Means for solving problems]

The above object of the present invention is to apply a coating solution containing a white pigment and an unsaturated organic compound having seven or more C═C double bonds in seven molecules that can be polymerized by an electron beam to a substrate (base paper or at least one of them). The side of the base paper coated with waterproof resin) is coated on the surface, and the amount of coating is at least! It is achieved by curing by applying electron beam irradiation while heating in the range of 10(: or more/ko θ0C or less) Preferably !0°C or more/200(: or less. If the heating temperature of the substrate is less than Jl 0C, hardening will occur. Coloring by development processing is not satisfactory because the properties are not sufficiently improved.Furthermore, heating the substrate at a temperature higher than 12θ0C causes n-order unevenness on the surface of the coating layer and deteriorates the flatness, so it is difficult to obtain a support that can withstand use. The irradiation dose is 01 megarad to 10 megarad, preferably 0, j Mrad = 1 megarad.If it is less than 0. Furthermore, if the absorbed dose is higher than 10 megarads, the yellowing of the base paper will be large and it will not be possible to obtain a product that can withstand use.

As the electron beam accelerator used in the present invention, a Bumpler-7 type scanning system, a double scanning system, or a curtain beam system can be adopted, but the curtain beam system is preferable because it is relatively inexpensive and can provide a large output. As for electron beam characteristics, acceleration voltage is / 00-/ 000
KV, preferably /θθ~J00Kv. If the accelerating voltage is less than 100 K"i, the amount of energy transmitted is insufficient, and if it exceeds 1000 K"i, the energy efficiency used for polymerization decreases and is not economical.The oxygen concentration during irradiation must be less than zoooppm. Preferably, z o
If o o p pm is larger, the curing reaction tends to be insufficient because oxygen interferes with the reaction.

Methods for heating the substrate include heating the irradiation chamber and blowing nine nitrogen to heat it to the desired temperature, heating the base paper substrate to the desired temperature by passing it over a heating roll, and heating it with infrared rays, lasers, or microscopy immediately before irradiation. An example is a method of heating the coating layer to a desired temperature by radiating waves toward the coating layer. Among them, heating efficiency is particularly high. A method of heating the base paper by passing it over a heating roll or a method of heating by radiating infrared rays is desirable.

Unsaturated organic compounds having 7 or more C=CJ double bonds in one molecule that can be polymerized by electron beams used in the present invention include unsaturated organic compounds having one C=C double bond in one molecule. Organic compounds (e.g. acrylic esters, methacrylic esters, ether acrylates), 2 in 7 molecules
Unsaturated organic compounds having 3 C=C double bonds (e.g. ester, ether, epoxy, urethane diacrylate or dimethacrylate), 3 C=C double bonds in one molecule
Unsaturated organic compounds with C double bonds (e.g. esters,
ether, epoxy, urethane triacrylate or trimethacrylate), φ C in one molecule
Unsaturated organic compound with λ double bond (e.g. ester, ether, epoxy, urethane-based tetraacrylate or tetramethacrylate), 7 C= in 7 molecules
Mention may be made of unsaturated organic compounds having a C double bond and seven epoxy groups (eg, epoxy acrylate, epoxy methacrylate). These may be used alone or in combination. A particularly preferred unsaturated organic compound when used alone is a tetraacrylate ester of an intererythritol alkylene oxide adduct represented by the following general formula.

[However, X is an oxyalkylene group and l)k+J+m+n=Jr]

Furthermore, when a mixture of unsaturated organic compounds is used, a mixture of diacrylate/triacrylate members represented by the following structural formula is particularly preferred.

Structural formula of diacrylate % Formula % Structural formula of triacrylate The above unsaturated compound is polymerized by subsequent electron beam irradiation treatment to form a resin component in the white pigment-containing resin layer. This resin functions to impart water resistance to the base paper and as a binder for the white pigment. Note that the resin in the white pigment-containing resin layer may be formed only from a polymer of the above-mentioned unsaturated compounds, but may also be formed from other resins (e.g., cellulose ester,
It may also be a mixture with polyvinyl butyral, polyvinyl acetate, vinyl acetate copolymer, polyester resin, styrene acrylate resin, polystyrene resin). However, when used in combination with other resins, the above-mentioned tetraacrylate ester of the intererythritol alkylene oxide adduct is used as an unsaturated compound.
Weight - or more is preferably used.

As the inorganic white pigment, those conventionally used for concealing photographic paper or those that have been proposed can be used. Examples include titanium dioxide, barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, lithopone, alumina white, zinc oxide, silica, antimony dioxide, titanium phosphate, and the like. These can be used alone or in combination.

As the inorganic white pigment, titanium dioxide is particularly preferred since it has a large hiding power. Titanium dioxide may be rutile-deaf or anatase-type, and these may be used alone or in combination. Further, it may be made by a sulfuric acid method or a chlorine method. Examples of titanium dioxide include those subjected to surface coating treatment with an inorganic substance such as hydrous alumina treatment and hydrous silicon dioxide treatment, trimethylolmethane, trimethylolethane, trimethylolethane, and λ.

≠=A material whose surface has been coated with an alcohol such as dihydroxy-comethylbentane or a material which has been subjected to a siloxane treatment can be used as appropriate.

The average particle diameter of the inorganic white pigment is preferably as large as 0 or i μm, and more preferably 0. It is particularly preferable that /J-μ is also large. Particle sizes less than 0.1 μm in diameter may be less likely to produce the desired improved resolution.

In the present invention, when forming a white pigment-containing resin layer, a coating liquid of a composition consisting of the above binder component (unsaturated compound and optionally resin) and a white pigment is prepared, and this coating liquid is applied to the surface of the base paper. . What is the ratio of binder component to white pigment? It is preferably in the range of / / to l/, particularly preferably in the range of 2//-//μ.

Incidentally, in addition to the white pigment, known additives for photographic paper supports, such as blue, purple, red pigments, or antistatic agents, may be used in combination, if desired.

The above composition for forming a white pigment-containing resin layer can be mixed and dispersed using a known mixer to form a coating solution. Examples of mixers include two-roll mill, three-roll mill, ball mill, pebble mill, tron mill, sand glider, Szegvari 7 triter, high-speed impeller dispersion, high-speed stone mill, high-speed impact mill, disperser, and kneader. -1 high speed mixer,
Homogenizers, ultrasonic dispersers, etc. can be used.

The coating liquid for forming the white pigment-containing resin layer may contain an organic solvent. Examples of such organic solvents include acetone, methyl ethyl ketone, methyl ibutyl ketone, keto/such as cyclohexanone; methyl acetate, ethyl acetate,
Esters such as butyl acetate, ethyl lactate, and acetic acid glycol monoethyl ether; Ethers; glycol ethers such as glycol dimethyl ether, glycol monoethyl ether, and dioxane; Aromatic hydrocarbons such as benzene, toluene, and xylene; methylene chloride, ethylene chloride, Examples include chlorinated hydrocarbons such as carbon tetrachloride, di-loloform, ethylene chlorohydrin, and dichlorobenzene.

The material for the base paper used in the present invention can be selected from known raw materials for supports. Examples include paper made from natural pulp, paper made from synthetic pulp made from plastic materials such as polyethylene or polypropylene, paper made by mixing natural pulp and synthetic pulp, or paper made from natural and synthetic pulp. Various materials such as paper made by knitting are used. It is also possible to use these base papers with a polyolefin layer such as polyethylene or polypropylene formed on the surface. That is, the white pigment-containing resin layer of the present invention may be provided directly on the base paper,
Alternatively, it may be provided on a polyolefin layer provided on the surface of the base paper. Further, if the base paper is provided with a water-resistant resin layer in advance on the other surface, there is no particular need to provide a water-resistant resin layer on the other surface.

Examples of methods for applying the above-mentioned coating liquid for forming a white pigment-containing resin layer onto base paper include air doctor coating,
Fred coat, air knife coat, squeeze coat,
Examples of conventional coating methods include impregnation coating, reverse roll coating, transfer roll coating, beer coating, kiss coating, cast coating, spray coating, and spin coating.

The thickness of the coating layer is generally 3 to 100μ, preferably t~! 0μ pain. Outside this range, uneven coating occurs, a large amount of energy is required for curing, and curing becomes insufficient, which is unfavorable in terms of quality.

In addition, in order to improve wetting and adhesion between the base paper and the coating layer, the surface of the base paper has been subjected to surface treatment such as corona treatment in advance.
The coating liquid described above may be applied.

The above-mentioned coating layer may have a surface smoothed with a mirror roll after coating or curing, or a matte roll with a matte roll such as a matte roll.

Further, the surface of the coating layer may be subjected to surface treatment such as corona treatment for the purpose of improving adhesion to the photographic emulsion layer. Alternatively, an undercoat layer may be provided on the surface of the coating layer.

The support of the present invention can be used as a photographic paper by forming a photographic emulsion layer (silver/gelatin light-sensitive emulsion layer) thereon according to known techniques.

Next, examples of the present invention and comparative examples will be shown. The expression "parts" in Examples and Comparative Examples indicates "parts by weight."

[Example 1] A coating solution having the composition shown below was prepared by mixing it in a ball mill for 20 hours, and then a base paper substrate with a thickness of 1102 m (both the front and back sides) was prepared so that the thickness of the coating layer after drying was 20 μm. 3Q
(on which a water-resistant resin layer made of polyethylene with a thickness of μ-island is formed) was coated on the front surface.

Coating liquid composition Rutile type titanium dioxide 30 parts Tetraacrylate ester of 1 mole adduct of intererythritol propylene oxide 30 parts The base paper substrate provided with this coating layer was passed over a heated roll and maintained at RO 0C under a nitrogen atmosphere (oxygen concentration J (7 ppm), and an accelerating voltage of 200 KV.

The coated layer was cured by irradiation with an electron beam at an absorbed dose of Megarad to obtain a support for photographic paper.

[Example 2] A base paper substrate provided with a coating layer having the same composition as in Example 1 was passed over a heating roll, and maintained at 4 cO0C under a nitrogen atmosphere (oxygen concentration "ppm") at an acceleration voltage λ00'KJ and an absorbed dose λ. The coated layer was cured by irradiation with electron beam at Megaland to obtain a support for photographic paper.

[Comparative Example 1] A base paper substrate provided with a coating layer having the same composition as in Example 1 was prepared at room temperature (2t'C) under a nitrogen atmosphere (oxygen concentration 300 ppm).
>1. The coated layer was cured by irradiation with an electron beam at an accelerating voltage of 200 KV and an absorbed dose of λO megaland to obtain a support for photographic paper.

[Comparative Example 2] A base paper substrate provided with a coating layer having the same composition as in Example 1 was prepared at room temperature (zt'c) under a nitrogen atmosphere (oxygen concentration 3ooppm).
), the coating layer was cured by irradiation with an electron beam at an accelerating voltage of 200 Kv and an absorbed dose of 2 Megaland to obtain a support for photographic paper.

[Comparative Example 3] A base paper substrate provided with a coating layer having the same composition as in Example 1 was
The coated layer was cured by irradiation with an electron beam at an acceleration voltage of -200 KV and an absorbed dose of 2 Megarads under a nitrogen atmosphere (oxygen concentration 30 ppm) to obtain a support for photographic paper.

Example! , 2 and Comparative Examples 1 to 3, the coloring after development, the yellowing of the base paper, and the flatness of the paper were evaluated using the following method f) W value.

l) Evaluation of coloring after color development The whiteness of the photographic paper support was measured before development, and then after development. The whiteness was measured using Color Analyzer Model 607 manufactured by Hitachi, Ltd., and the spectral reflectance at wavelength ≠ Hiroo 0 screen μ was taken as the whiteness.

The above-mentioned whiteness before the development process and the whiteness after the development process were determined, and this was defined as the degree of coloration. Therefore, the lower the degree of coloring, the less coloring caused by the development process.

−) Evaluation of yellowing of base paper The polyethylene and hardened layer were removed from the base paper before electron beam irradiation treatment, the base paper obtained by removing the polyethylene layer, and the photographic paper support obtained after electron beam irradiation treatment. The whiteness of the base paper obtained was measured. The whiteness was measured using ■Color Analyzer 407 manufactured by Hitachi, Ltd.
The spectral reflectance at is defined as the whiteness.

The value obtained by subtracting the whiteness of the base paper after the electron beam irradiation treatment from the whiteness of the base paper before the electron beam irradiation treatment was defined as the yellowing degree of the base paper.

This means that the yellowing of the base paper due to electron beam irradiation is small.

3) Evaluation of flatness The degree of unevenness on the surface of the photographic paper support prepared by electron beam curing treatment was visually determined.

The results obtained are shown in Table 1.

Table l Example 1 0.2 0. J Section 012
0,j% 0.2%○ Comparative Example 1 0. J Chi 10. J-chi 0
12 //, 0chi 0. J Chi 0 13 0, ≠ Chi O6! [Effects of the Invention] From the results shown in Table 1, the support for photographic paper according to the present invention has significantly improved coloring after development, and hardly worsens the yellowing of the base paper, making it an excellent support. It can be said. On the other hand, the support for photographic paper of the comparative example is not suitable as a practical support for photographic paper because either the yellowing of the colored base paper after the development treatment or the flatness is extremely poor.

Furthermore, after corona discharge treatment was applied to the surface of the photographic paper support obtained in Examples 1 and 2 on the side of the white pigment-containing resin layer,
A color photographic paper was prepared by adding a silver/gelatin photographic emulsion layer and a protective gelatin layer according to a known technique. When we investigated the characteristics of color photographic paper, we found that
Photographic properties such as sensitivity and fog were good, and high resolution and high gloss were exhibited.

Patent Applicant Fuji Photo Film Co., Ltd. Voluntary Procedural Amendment Statement 1985//Month/Date 1, Case Indication 1965 Patent Application No. 101441
No. 1, No. 2, Title of the invention Method for producing a support for photographic paper 3, Relationship with the case of the person making the amendment Patent applicant contact information 10
6 2-26-30 Nishi-Azabu, Minato-ku, Tokyo Subject of amendment The "Detailed Description of the Invention" column of the specification & contents of the amendment The specification will be amended as follows.

(Page 112, page l line "melt" "melting" and correct it.

(2) First line of page “Expensive base paper base” "High base paper base" and correct it.

(3) Page 7 "Diacrylate/Triacrylate ///J "Diacrylate/Triacrylate 2/3" and correct it.

(4) //Page λth line "Ball mill, pebble mill" "Ball mill, pebble mill" and correct it.

(5) / 4th page page line "Find the whiteness of" "Find the whiteness difference" and correct it.

Claims (1)

[Claims] One or more C=C in one molecule that can be polymerized by electron beam
After forming a coating layer by applying a coating solution containing an unsaturated organic compound having a double bond and a white pigment to the base paper or the surface of the base paper whose at least one side is coated with a waterproof resin, the coating layer is A method for producing a support for photographic paper, which comprises curing and forming a support by applying electron beam irradiation while heating at a temperature of at least 35°C to 120°C.