JPH01123230A - Base for photographic paper and its production - Google Patents

Abstract

PURPOSE:To obtain the title base which has excellent whiteness and opacity and has excellent smoothness, fogging preventiveness, color reproducibility, and fading resistance by constituting the base in such a manner that the base has the layer formed by curing an electron radiation curing type compsn. consisting of a white pigment and electron radiation curing type resin by electron beam irradiation on the base and that a polyolefin resin is coated thereon. CONSTITUTION:This base has the structure in which the base has the layer formed by curing the electron radiation curing type compsn. consisting of the white pigment and electron radiation curing type resin by electron beam irradiation on at least one face thereof and that the polyolefin resin is coated thereon. The performances such as whiteness, opacity, reduction of the film of the resin layer contg. the white pigment, and low temp. film formability are obtd. by the electron radiation curing type compsn. layer provided on base paper and the performances such as the smoothness on the extreme surface of the base for photographic paper, water resistance, chemical resistance, easy cleanability, adhesiveness to a photosensitive emulsion layer and fogging preventiveness of a photosensitive emulsion are obtd. by the resin layer consisting of the polyolefin resin.

Description

[Detailed description of the invention] (A) Industrial application field The present invention relates to a support for photographic paper.

More specifically, the present invention relates to a water-resistant support for photographic paper, in which an electron beam curable resin layer containing a white raw material is provided on the surface of a base paper for photographic paper, and the layer is coated with a polyolefin resin.

CB) Prior Art In recent years, as a support for photographic stamp paper, waterproof paper in which a polyolefin resin layer into which a white pigment has been kneaded is provided on the surface of the base paper, which is the support, has been mainly used.

The main reason for providing a polyolefin resin layer on the base paper is to prevent processing chemicals from penetrating into the base paper during development, and this i-layer makes it possible to shorten the development time, and also Since no processed material remains in the base paper, yellowing due to aging can be avoided. Coating of base paper with such polyolefin resin is generally carried out using a melt extruder. Furthermore, inorganic white pigments such as titanium dioxide are added to the polyolefin resin layer on the surface of the photographic paper in order to improve the hiding power and whiteness of the photographic paper support and to improve the resolution of the photographic paper. is elaborated. However, polyolefin resins have extremely high viscosity even when hot-melted, making it difficult to disperse inorganic pigments such as titanium dioxide, and the types of polyolefin resins that can be used are limited. Furthermore, there is a limit to the filling rate of the mH-free material, and in order to obtain a certain degree of hiding power and whiteness, it is necessary to increase the resin thickness. Further, since such melt extrusion coating of polyolefin resin is performed at a temperature higher than the thermal decomposition temperature of the polyolefin resin, yellowing and pinholes are generated in the resin layer due to thermal decomposition of the resin. Furthermore, as the extrusion speed increases, the adhesion to the base paper decreases.

This had the disadvantage of causing a decline in the quality of the final product.

[C] In manufacturing a support for photographic paper coated with fat-soluble resin, which the invention seeks to solve, if a melt extrusion method is used, the resin coating layer can be thinned while maintaining an appropriate hiding power. Since it is difficult to increase the coating speed without deteriorating the quality, we coated the base paper for photographic paper with an electron beam curable resin kneaded with white pigment, and then irradiated it with electron beams. A method of producing a water-resistant photographic paper support by forming a coating layer has been proposed (for example, Japanese Patent Publication No. Sho Go-17104).

In this method, a coating liquid in which a white pigment is dispersed at a high concentration in a resin such as acrylate ester having unsaturated bonds that can be polymerized by electron beam irradiation is applied onto the base paper for photographic printing paper.
Because this method forms a resin coating layer on the surface of the base paper by polymerizing and crosslinking using electron beam irradiation at room temperature, the resin layer can be made thinner without reducing the hiding power, and the yellowing of the resin caused by the melt extrusion method can be avoided. , generation of pinholes,
It becomes possible to produce a water-resistant support for photographic paper without deteriorating the quality of the final product due to poor adhesion of the resin layer, blocking, or matte finish. However, in the electron beam curable resin layer containing the white pigment prepared in this way, so-called fog occurs in which the portions that are not exposed during the development process ffi are developed.

There are many resins that adsorb developer, etc. and cause yellowing over time, which is a fatal problem for photographic paper supports, and the resins that can be used are extremely limited. Ta.

[D] Means for Solving the Problems As a result of intensive research into means for solving the above-mentioned problems, the present invention has led to the discovery of the following method.

That is, there is a layer on at least one surface of the support in which an electron beam curable composition consisting of a white pigment and an electron beam curable resin is cured by electron beam irradiation, and the layer is coated with a polyolefin resin. This is an invention of a support for photographic paper characterized by the following.

The present invention will be described in detail below with reference to the drawings.

A schematic diagram of a cross section of a support for photographic paper according to the present invention is shown in FIG.
The photographic paper support 1 shown in the figure has a structure in which an electron beam curable composition 3 containing a white pigment is placed on a base paper 2, and a coating layer 4 made of a polyolefin resin is provided on top of the electron beam curable composition 3. . A back surface coating layer 5 made of a polyolefin resin or an electron beam curable composition is provided on the back surface of the base paper 2, if necessary.

In the support for photographic paper in the present invention, whiteness,
The electron beam curable composition layer provided on the base paper is responsible for performance such as opacity, three-layer resin layer containing white pigment, and low-temperature film formability, and smoothness on the outermost surface of the support for photographic printing paper. The polyolefin resin coating layer has the following properties: water resistance, scuff resistance, easy cleaning, adhesion to the photosensitive emulsion layer, and antifogging properties of the photosensitive emulsion.

The electron beam curable resin constituting the electron beam curable composition used in the present invention takes into consideration conditions such as electron beam curability, high concentration dispersibility of white pigment, weather resistance, film strength, heat resistance, and curling properties. You can choose. Examples of electron beam polymerizable resins include unsaturated polyesters, modified unsaturated polyesters, and modified unsaturated polyesters having an electron beam reactive group at the molecular end or in the side chain of the molecule.
Acrylic polymers and monomers having unsaturated bonds can be used alone or in combination with other solvents.

Representative examples of electron beam polymerizable resins are shown below.

(a) Polyester acrylate, polyester methacrylate, e.g. Aronix M-5300, Aronix M-
5400, Aronix M-5500, Aronix M
-5600, Aronix M-5700, Aronix M-6100, Aronix M-6200, Aronix M-6300. Aronix M-6500, Aronix M-7100, Aronix M-8030, Aronix M-8060, Aronix M-8100 (and above).

Toagosei Chemical Industry Co., Ltd. (product name), Viscodoor 00,
Visco) 3700 (all trade names of Osaka 2-ki Kagaku Kogyo Co., Ltd.), Kayarad HX-220, Kayarad HX
-620 (1 Nippon Kako Co., Ltd. product name) (b) Urethane acrylate, urethane methacrylate For example, Aronix M-1100, Aronix M-
1200, Aronix M-1210, Aronix M
-1250, Aronix M-1260, Aronix M-1300, Aronix M-1310C and above, Toagosei Chemical Co., Ltd. brand name), Visco-1-812, Visco-1-823, Visco-1-823 (and above, Osaka Organic Chemical Industry Co., Ltd. (Product name)-NK ester, U-108
-A, NK ester, U-48A (The above are trade names of Shin Nakamura Chemical Co., Ltd.) (C) Monofunctional acrylate, monofunctional methacrylate, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate,
Cyclohexyl methacrylate, benzyl acrylate, glycidyl methacrylate, N-N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate-1-N, N-dimethylaminoethyl acrylate, br-xyethyl acrylate, etc., ethylene oxide modified phenoxy Oxylated phosphoric acid acrylate ethylene oxide modified P1 to oxidized phosphoric acid acrylate, and other product names of Toagosei Kagaku Kogyo Co., Ltd. such as Aronix M-101, Aronix M-102, Aronix M
-111, Aronix M-113-Aronix M-
114, Aronix M-117, Aronix M-1
52, Aronix M-154, etc.

(d) polyfunctional acrylate, polyfunctional methacrylate, e.g. 1,6-hexanediol diacrylate,
1,6-hexanediol diacrylate, neopentyl glycol diacrylate 1-, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polybrobylene glycol dimethacrylate-1, pentaerythritol diacrylate, dipentaerythritol hexaacrylate, isocyanuric acid diacrylate-1, pentaerythritol triacrylate, isocyanuric acid triacrylate, trimethylolpropane triacrylate,
Examples include trimethylolpropane 1-remethacrylate, ethylene oxide-modified pentaerythritol tetraacrylate, propylene oxide-modified pentaerythritol tetraacrylate tall polyacrylate, ethylene oxide-modified dipentaerythritol polyacrylate-1, and acrylate ester of pentaerythritol acrylic acid adduct. It will be done. The product names of Toagosei Chemical Industry Co., Ltd. are Aronix M-210, Aronix M-215, Aronix M-220, Aronix M-230, Aronix M-233, Aronix M-240, Aronix M-245, Aronix M. -305, Aronix M-310, Aronix M-315, Aronix M-320- Aronix M-325, Aronix M-330, Aronix M-400, Aronix M-450, TO- 45
8, TO-747, To-755-THIC, TA2, etc.

As the white pigment in the electron beam curable composition used in the present invention, white pigments such as rutile-coated or anatase type titanium dioxide, zinc oxide, talc, calcium carbonate, barium carbonate, barium sulfate, calcium sulfate-silica, etc. It can be used untreated or after surface treatment with siloxane, alumina, alcohol, etc. The proportion of the white pigment in the electron beam curable composition is preferably 20% to 80% by weight, and especially 2% to 80% by weight.
Preferably in the range of 0% to 70% by weight,
This means that if the proportion of white pigment is extremely small, it will not have the expected hiding power, and if it is too large, it will not only lack the ability to act as a binder for electron beam curable fat, but also cause electron beam curable properties. This is because it causes an increase in the amount of water and has an undesirable effect on the base paper for photographic paper or the coating resin.

The polyolefin resin used in the present invention is an olefin homopolymer such as polyethylene, polypropylene, polybutene, polypentene, or ethylene-
Copolymers consisting of two or more types of olefins, such as propylene copolymers, and mixtures thereof, with various densities and melt viscosities (melt index, hereinafter simply referred to as MI), used singly or in mixtures. Can be done.

Further, the polyolefin resin in the present invention may be used alone, but it may also contain a white pigment for the purpose of improving whiteness and opacity and reducing diffused reflection of light in the polyolefin resin layer. Contains stearic acid amide.

Aliphatic amides such as araxinamide, aliphatic metal salts such as zinc stearate, calcium stearate, magnesium stearate, calcium palmitate, ultramarine,
It is preferable to add pigments such as cobalt violet and various additives such as dyes, antioxidants, fluorescent brighteners, and ultraviolet absorbers in appropriate combinations.

The electron beam curable composition and polyolefin resin of the present invention contain ultramarine blue, cobalt violet resin, etc., which are used in the surface polyethylene layer of photographic paper supports prepared by conventional polyolefin resin melt extrusion methods.
Various additives such as pigments and dyes, antioxidants, optical brighteners, and antistatic agents can be added in appropriate combinations.

In the present invention, since the electron beam curable resin is formed into a film by electron beam irradiation, a reaction initiator is not required in principle, but a photoreaction initiator may be mixed in for the purpose of reducing unreacted resin. As photoinitiators, acetophenones such as di- and l-lichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin,
There are benzoin alkyl ethers, penzyl dimedyl ketal, tetramethylthiuram monosulfide, thioxanthones, azo compounds, various silver salts, etc., and those using photoinitiators are electron beam curable! For JrN, usually 0
．． It is in the range of 1 to 10%. Further, a storage stabilizer such as hydroquinone may be used in combination with the photoinitiator.

The base paper used as a support in the present invention is ordinary natural valve paper 1 synthetic fiber, so-called synthetic paper made from a synthetic resin film, resin-coated paper with a water-resistant resin coating layer on the surface of the base paper, or Although synthetic resin sheets can be used, natural pulp paper whose main component is wood valves such as softwood valves, hardwood valves, and mixed softwood and hardwood valves is advantageously used. There is no particular restriction on the thickness of the base paper, but it is preferable to use paper with good smoothness, and its basis weight is preferably 50 g/lu'' to 250 g/ba.

The base paper containing natural pulp as a main component, which is advantageously used in the method of the present invention, contains various animal molecule compounds.

Additives can be included. for example.

Dry paper strength enhancers such as starch derivatives, polyacrylamides, polyvinyl alcohol derivatives, gelatin, sizing agents such as fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, wet paper strength enhancers such as melamine resins, urea resins, epoxidized polyamides, etc. agents, stabilizers, pigments, dyes, antioxidants, optical brighteners, various radex, inorganic electrolytes, pH
Xl1i! A suitable combination of stabilizers and the like may be included.

In addition, in the present invention, even if the surface of the base paper is subjected to surface treatment such as corona treatment in order to improve the adhesion and wettability between the base paper and the electron beam curable composition, the resin and polyolefin formed into a film by electron beam irradiation may also be applied. In order to improve the adhesion with the resin, the adhesion between the polyolefin resin and the photosensitive emulsion, and the wettability, the surface of each resin may be subjected to surface treatment such as corona treatment.

A common pigment kneading machine can be used to prepare an electron beam curable composition by mixing a white pigment with an electron beam curable resin. For example, two rolls, three rolls,
These include ball mills, Ni-Goo, high-speed mixers, homogenizers, etc.

The method for applying the electron beam curable composition onto base paper is as follows:
For example, methods such as blade coating, air doctor coating, air knife coating, spray coating, squeeze coating, air knife coating, reverse roll coating, gravure roll and transfer roll coating, and E barcode are used.

The thickness of the electron beam polymerizable composition layer applied onto the base paper varies depending on the type of base paper, but is preferably 5 to 100 μm, more preferably 1 μm.
The thickness is 0 to 50 μm, and if it is thinner than this, it will be easily affected by the unevenness of the base paper and pinholes will be generated. If it is thicker than this, it will not only be difficult to coat uniformly but also hard to cure uniformly, which is not desirable in terms of quality. .

The thickness of the polyolefin resin layer provided on the coated resin layer made of electron beam curable resin is sufficient as long as it has sufficient heat to prevent fogging and developer adsorption, and is generally 2 to 20 μm, more preferably 5 to 15 μm thick. If the thickness is thinner than this, there will be problems in anti-adsorption properties, film forming properties, adhesion, etc., and if it is thicker than this, it is unfavorable in terms of economic efficiency and properties when used as photographic paper.

When mirror-finishing the surface of the polyolefin resin coating layer, the surface to be treated can be brought into contact with a mirror-finished roll after melt extrusion.

When applying a pattern, a desired patterned surface such as a slightly rough surface can be obtained by using a patterning roll instead of a mirror-finished roll.

The adhesion between the polyolefin resin and the electron beam curable composition layer may be achieved by melt-laminating the polyolefin resin on the electron beam curable composition layer cured by electron beam irradiation, or by bonding the polyolefin resin. Applying an electron beam curable composition f& Without electron beam irradiation, or after preliminary electron beam irradiation to partially cure the electron beam curable composition layer, melt lamination is performed, and then bonding is performed by electron beam irradiation. You may do so.

For electron beam irradiation, the acceleration voltage is 10 from the viewpoint of penetrating power and curing power.
0 to 100 OKV, more preferably 100 to 30
It is preferable to use a 0 KV electron beam accelerator so that the absorbed dose in one pass is 0.5 to 20 Mrad. If the accelerating voltage or the electron beam irradiation amount is lower than this range, the penetrating power of the electron beam will be low. If it is too large, sufficient curing will not take place, and if it is too large, energy efficiency will not only deteriorate, but also undesirable effects on quality will occur, such as a decrease in the strength of the base paper and decomposition of the resin. The electron beam accelerator may be, for example, an electrocurtain system, a scanning type, a double scanning type, or the like.

Note that when electron beam irradiation is performed, a high oxygen concentration will hinder the curing of the electron beam polymerizable composition, so nitrogen, helium,
It is preferable to carry out substitution with an inert gas such as carbon dioxide and irradiate in an fTJ-like atmosphere so that the oxygen concentration is 600 pp@ or less, preferably 400 ppya or less.

Further, the back side of the photographic paper support of the present invention can be coated with a polyolefin resin by the conventional melt extrusion method, or coated with an electron beam curable resin.
A resin coating layer can be formed by a method of forming a coating by irradiation with a ray of light, and a back coat layer can be provided so as to provide writing properties on the back side.

The support for photographic paper prepared according to the present invention can be used as photographic paper by coating a photosensitive emulsion thereon.

CE] Function The support for photographic paper produced in the present invention has excellent water resistance, hiding power, and whiteness, and has excellent water resistance, hiding power, and whiteness, and is resistant to electron beam curable resin. Due to the function of the polyolefin resin layer provided on the curable resin layer, it has excellent photographic properties, adhesive properties, and developer adsorption prevention properties when used as photographic paper.

CF) Examples The present invention will be explained in detail below using examples, but the content of the present invention is not limited to the examples.

Implementation @-1 On the back side, low density polyethylene (density 0918g/cm3
- After performing corona treatment on the surface of photographic base paper with a thickness of 120 g/m" and laminated with a thickness of 20 μm using MI5), an electron beam curable composition having the following ffl composition was applied to a thickness of 20 μm. coating, nitrogen equipment 111
1 m (oxygen concentration 200 ppm) I, electron beam irradiation device (
The electron beam curable composition was cured by conducting electron beam irradiation under the conditions of an acceleration voltage of 175 kV and an absorption line fL of 2 megalats.

[Electron beam curable composition]

Rutile type titanium dioxide 50 tH% electron beam curable resin 50tH% electron beam curable resin is α, ω-diacryloyl (bisethylene glycol)
-30% by weight of phthalate and 2-hydroxy-3-phenoxypropyl acrylate
A mixture of 70 layers was used.

The electron beam curable resin and the rutile titanium dioxide are mixed using a triple roll.

The sheet obtained as above was subjected to corona treatment,
Polyethylene resin [low density polyethylene (density 09L8)
g/am3, MI5) and high density polyethylene (density 09
65g/cm', 5μm by an equal mixture of MI7)
A support for photographic paper was obtained by coating with a laminate to a thickness of .

Example 2 Using base paper for photographic paper with polyethylene lamination on the back side as in Example 1, an electron beam curable composition, and a polyethylene resin for the front surface, a base paper for photographic paper was prepared in the following steps. A support was obtained.

After corona treatment was applied to the surface of the base paper for photographic paper, an electron beam curable resin layer was applied to a thickness of 20 μm.

A polyethylene layer with a thickness of 5 μm was provided thereon by melt lamination without electron beam irradiation, and immediately thereafter, electron beam irradiation was performed at an irradiation dose of 3 Mrad to obtain a support for photographic paper.

Implementation PA-3 Using base paper for photographic paper with polyethylene lamination on the back side as in Example-1, an electron beam curable composition, and a polyethylene resin for the front side, a support for photographic paper was prepared in the following steps. I got it.

After corona treatment was applied to the surface of a base paper for photographic paper, an electron beam curable composition was applied to a thickness of 20 μm.

After curing a part of the electron beam curable composition at an irradiation dose of 0.3 Mrad, a polyethylene laminate was applied thereon, and immediately after that, electron beam irradiation was performed at an irradiation dose of 112.7 Mrad to form a support for photographic paper. I got it.

Implementation @-4 Using the same photographic paper base paper with polyethylene lamination on the back side as in Example-1 and the electron beam curable composition, only the polyethylene resin for the front side was changed to the following composition.

Required polyethylene resin used in Example-1 95% by weight Titanium dioxide (rutile type) 5% by weight Electron beam curable composition cured by electron beam irradiation on base paper for photographic paper in the same process as in Example-1 A support for a photographic aperture 1iljK provided with a 'j@ layer and a polyolefin resin layer was obtained.

Comparative Example-1 Example-1 except that no laminate layer was provided on the outermost layer
In the same manner as above, a support for photographic paper was obtained, in which a layer of an electron beam curable composition cured by electron beam irradiation was provided on a base paper for photographic paper.

The photographic paper supports prepared in Examples jIA-1, 2, 3, and 4 and Comparative Example 1 were subjected to a series of development treatments in a conventional manner.

The rate of change in whiteness (Macbeth reflection densitometer, RD-514, yellow filter used) of the photographic paper support before and after development was used as a measure of adsorption of processing chemicals.

In addition, the adhesion between the base paper layer and the resin layer of the photographic paper support after the development treatment was visually determined.

Table 1 summarizes the whiteness change rates of the photographic paper supports prepared in Examples 1, 2, 3, and 4 and Comparative Example 1. Naturally, the smaller the rate of change in whiteness, the less residual processing chemicals will remain during development, making it an excellent support for photographic paper.

Table 1 Sample Whiteness change rate Adhesion (%) Example-10 Good example-20 Good example-30! +, Good Example - 40 Good Comparative Example - 138 Good [G] Effects of the Invention As is clear from Table 1, the present invention enables flat filling of white pigment into the electron beam curable composition at the time of preparation. Since it has excellent whiteness and opacity and has a polyolefin resin layer on the outermost layer, it provides a support for photographic printing paper that is excellent in smoothness, anti-fogging properties, and anti-adsorption properties for developer and the like. Further, the support for photographic paper produced in the present invention provides photographic paper with less residual chemicals after development and excellent color reproducibility and fading resistance. Furthermore, any electron beam curable resin can be selected in consideration of the physical properties and economic efficiency of the support for photographic paper.

(Margin below)

Claims (5)

[Claims] (1) It has a structure in which there is a layer on at least one surface of the support in which an electron beam curable composition consisting of a white pigment and an electron beam curable resin is cured by electron beam irradiation, and the layer is coated with a polyolefin resin. A support for photographic paper characterized by: (2) The support for photographic paper according to claim 1, wherein the polyolefin resin contains a white pigment. (3) In the electron beam curable composition, the white pigment contains 20
The support for photographic paper according to Claims 1 and 2, characterized in that the content is from % by weight to 80% by weight. (4) A method for producing a support for photographic paper, characterized in that the electron beam curable composition is cured by electron beam irradiation after being coated with a polyolefin resin. (5) After partially curing the electron beam curable composition by first electron beam irradiation, coating with the polyolefin resin is performed, and then curing the electron beam curable composition by second electron beam irradiation. A method for producing a support for photographic paper according to claim 4, characterized in that: