JP2003330146A - Method for producing support for recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a support for a recording material by which the process from a step of covering a paper substrate with a water resistant resin to a step of coating with an undercoat layer can be continuously carried out by reducing the coating weight of a coating liquid for an undercoat layer to reduce the load on a drying step after coating. <P>SOLUTION: In the method for producing a support for a recording material in which a water resistant resin covering layer is disposed on both faces of a paper substrate and an undercoat layer comprising a white pigment and a hydrophilic colloidal component is disposed on the water resistant resin covering layer on the side to be coated with a recording layer, wet coating weight in disposal of the undercoat layer by coating is ≤20 g/m<SP>2</SP>and at least the process from the step of laminating the water resistant resin covering layer to the step of coating with the undercoat layer is continuously carried out. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a support for recording materials, and more particularly to a method for producing a support for recording materials suitable for silver halide photographic light-sensitive materials.

[0002]

2. Description of the Related Art A so-called resin coating in which a paper base is coated with a water-resistant resin as a support for recording materials used in full-color thermal paper, ink jet image receiving paper, electrostatic recording image receiving paper, silver halide photographic light-sensitive materials and the like. Paper is used,
For example, Japanese Patent Publication No. 2-29203, Japanese Patent Publication No. 5-80
655, JP 3220831 or JP-A 7-2.
For details, refer to Japanese Patent No. 30141.

When resin-coated paper is used as a support for recording materials, an undercoat layer is provided in order to prevent the layer provided on the support from peeling off from the support. This undercoat layer is formed by applying to the support an undercoat layer coating solution consisting of a hydrophilic colloid component such as gelatin and water, but when the coating amount of the undercoat layer coating solution is large, There is a problem that the load in the drying process is high and the productivity does not increase.

When the support for recording materials is used in a silver halide photographic light-sensitive material, etc., if the amount of the hydrophilic colloid component coated on the support is large, it is absorbed by the support during the development processing. There is a problem that the amount of the developer is large and the load of drying the support after the development processing is high.

On the other hand, a method of adding a white pigment to a support is known as a means for improving the sharpness of a recording material, particularly a support for photographic paper. Barium sulfate is dispersed in gelatin as a support for photographic paper. A so-called baryta paper obtained by coating the surface of a base paper with the suspension and a so-called resin-coated paper obtained by coating a base paper with a polyolefin resin filled with titanium oxide are used.

A printing paper having a photographic light-sensitive emulsion coated on the surface of a baryta paper has a drawback that the baryta layer or the base paper absorbs the developing solution or water in the developing process, which requires a long drying time. For the purpose of overcoming the drawback, a photographic printing paper in which a photographic photosensitive emulsion is coated on a polyolefin resin-coated paper is mainly used recently. However,
Compared to the conventional photographic image obtained from a photographic printing paper having a baryta paper as a support, the photographic image obtained from a photographic printing paper having a polyolefin-coated paper as a support has a drawback of poor resolution. The cause of this defect is that the amount of white pigment kneaded in the polyolefin layer coated on the surface of the polyolefin-coated support in contact with the photosensitive silver halide emulsion is small and the light-shielding effect is not sufficient. It is considered that light is scattered in the polyolefin layer.

Titanium oxide is usually used as the white pigment contained in the above-mentioned polyolefin layer. However, it is a special feature to improve the surface coating of titanium oxide so that the amount of filler in the polyolefin can be increased. It is disclosed in JP-A-55-108658, JP-A-57-35855 and the like, and the combination with other pigments is disclosed in JP-B-49-27046. However, in any case, the possible filling amount of titanium oxide is at most 15
It is only mass%. Therefore, a method of providing a white pigment layer comprising a white pigment and a hydrophilic colloid solution on a film or a resin-coated paper, and providing a photographic light-sensitive emulsion layer on the white pigment layer is disclosed in JP-B-57-53937. It is described in, for example, KAI Sho 57-64235. In the photographic paper using the support described in these, since the binder of the white pigment layer is hydrophilic, it absorbs the development processing solution and water, and drying is a photographic paper using a normal polyolefin-coated paper as the support. In comparison, it has the drawback of being delayed.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and achieve the following objects. That is, the present invention continuously performs from the waterproof resin coating step to the undercoat layer coating step on the paper substrate by suppressing the coating amount of the undercoat layer coating solution to reduce the load of the drying step after coating. Provided is a method for producing a support for a recording material that can be used.

[0009]

The present invention provides <1> a water-resistant resin coating layer on both sides of a paper base, and a white pigment and hydrophilicity on the water-resistant resin coating layer on the side to which a recording layer is applied. A method for producing a support for a recording material provided with an undercoat layer containing a colloid component, wherein a wet coating amount when applying the undercoat layer is 20 g / m ² or less, and at least the water resistance. In the method for producing a support for recording materials, a lamination process of a resin coating layer and a coating process of the undercoat layer are continuously performed. <2> The coating amount of the hydrophilic colloid contained in the undercoat layer is 1.0 g / m ² or less <1>
The method for producing a support for recording material as described in 1. <3><1> or <2>, wherein the white pigment contained in the undercoat layer has a mass content of 50% or more.
The method for producing a support for recording material as described in 1. <4> The method for producing a support for recording material according to any one of <1> to <3>, wherein the solvent of the coating liquid for the undercoat layer is a mixed solvent of water and alcohol.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a recording material support according to the present invention will be described in detail below. The recording material support produced by the production method of the present invention has a water-resistant resin coating layer on both sides of the paper substrate, and in the undercoat layer in contact with the water-resistant resin coating layer on the side on which the recording layer is applied, It contains a white pigment and a hydrophilic colloid component.

(Paper Substrate) The paper used as a substrate in the present invention is not particularly limited, and paper made of natural pulp, synthetic pulp or the like can be used. As a particularly preferred paper substrate, containing an epoxidized fatty acid amide,
After making paper from a paper material whose pH is adjusted to 5.5 to 6.5, and then adjusting its water content to 1 to 4% by mass, surface sizing is performed using an alkaline aqueous solution to adjust the pH of the paper surface to 7
The base paper (Japanese Patent Application No. 4-97365) adjusted to 8 can be mentioned. In the present invention, JIS P811
A paper base having a smooth surface having a Beck's smoothness defined by 9 of 100 seconds or more is preferable, and one having a smooth surface of 200 seconds or more is particularly preferable.

As a method for producing a paper substrate having a Beck's smoothness of 100 or more, generally, a hardwood pulp, which is short fiber and easily smooth, is used in a large amount, and the long fiber content is reduced as much as possible by a beating machine. Beat up. In this case, the beating of the pulp is preferably such that the fiber length of the beating pulp is such that the 42 mesh residue is 20 to 45% and the freeness is 20 to 350 CSF.

[0013] While not specifically defined, the thickness of the paper base, its basis weight is preferably ^{40g / m 2 ~250g / m 2} . In the paper substrate of the present invention, a product name or the like may be printed on the surface opposite to the surface on which the recording layer is applied, if necessary. The printing method in this case may be any general printing method such as gravure printing, flexographic printing, letterpress printing or offset printing.

(Water-Resistant Resin Coating Layer) The paper substrate is coated on both sides with a water-resistant resin. The coating is applied first to the uncoated back side of the recording layer and then to the coated front side of the recording layer. In particular, when the front surface is coated, it is preferable to contain fine particles of titanium dioxide and, if necessary, further contain a bluing agent. The coating layer is
It may be a single layer or a plurality of layers of two or more layers. In the case of forming a plurality of layers, it is preferable to apply all layers at the same time from the viewpoint of reducing the number of steps.

Examples of the water-resistant resin used include polyolefins such as polyethylene, polypropylene, and polyethylene-based copolymers, with polyethylene being particularly preferred. As the polyethylene, high density polyethylene, low density polyethylene, linear low density polyethylene and a mixture of these polyethylenes can be used. In addition, the melt flow rate of polyolefin resin before processing (hereinafter M
(Abbreviated as FR) is a value measured under condition 4 of Table 1 of JIS K 7210 and is preferably in the range of 1.2 g / 10 minutes to 12 g / 10 minutes. The MFR before processing of the polyolefin resin described in this specification means the MFR of the resin before kneading the bluing agent and titanium dioxide and the MFR before using the diluting resin.

As the bluing agent contained in the water resistant resin coating layer, generally known ultramarine blue, cobalt blue,
Cobalt oxide phosphate, quinacridone pigment, and the like and mixtures thereof are used. The particle size of the bluing agent is not particularly limited, but the particle size of commercially available bluing agents is usually 0.3 μm to
The particle size is about 10 μm, and if the particle size is within this range, there is no particular problem in use. Also, different bluing agents may be used for the upper and lower layers.

When the water resistant resin coating layer of the recording material support of the present invention has a multi-layer structure, the content of the bluing agent in the uppermost layer is 0.01 to 0.8% by mass, preferably 0.05 to 0.6% by mass, particularly preferably 0.1% by mass
~ 0.4% by mass, or 0% on the lower layer side
0.6% by mass, preferably 0.01 to 0.45% by mass, and particularly preferably 0.05 to 0.3% by mass.

The titanium dioxide contained in the water resistant resin coating layer together with the bluing agent is anatase type,
Either rutile type may be used, but when priority is given to whiteness, anatase type titanium dioxide is used, and when sharpness is prioritized, rutile type titanium dioxide is preferably used. Anatase type and rutile type titanium dioxide may be blended and used in consideration of both whiteness and sharpness, or anatase type titanium dioxide may be used for the upper layer and rutile type titanium dioxide for the lower layer. The titanium dioxide concentration in the upper and lower layers is 5% by mass to 20%.
Any concentration of titanium dioxide can be used between% by weight. The upper and lower layers may have different concentrations.

The titanium dioxide used is generally one whose surface is treated with an inorganic substance such as hydrous aluminum oxide or hydrous silicon oxide, or a polyhydric alcohol, in order to suppress the activity of titanium dioxide and prevent yellowing. Polyvalent amine,
The thing surface-treated with organic substances, such as metal soap, an alkyl titanate, and polysiloxane, can be used. The amount of surface treatment is preferably 0.2% by mass to 2.0% by mass with respect to titanium dioxide and 0.1% by mass to 1.0% by mass with respect to the organic substance. The particle size of titanium dioxide is 0.
It is preferably about 1 μm to 0.4 μm.

The water-resistant resin coating layer coated on at least the recording layer side of the present invention may appropriately contain known additives such as antioxidants, lubricants, surfactants and non-dripping agents. You can

The above-mentioned antioxidant is used in order to prevent the resin from being oxidatively decomposed to generate an aldehyde, a ketone or the like, thereby causing fog or abnormal sensitivity on the photographic film.
Alternatively, it can be added from the viewpoint of preventing the generation of non-soluble foreign substances and coloring failure. Representative examples of such antioxidants include, for example, phenolic antioxidants, ketone amine condensation antioxidants, allylamine antioxidants, imidazole antioxidants, phosphite antioxidants or thiourea antioxidants. Agents and the like. Representative examples of these antioxidants are described in detail in JP-A-7-261322.

The lubricant can be added to improve the kneading properties of other additives. Representative examples of the lubricant include fatty acid amide lubricants, silicone lubricants, nonionic surfactant lubricants, hydrocarbon lubricants, fatty acid lubricants, ester lubricants, alcohol lubricants and metal soaps. Representative examples of these lubricants are described in detail in JP-A-7-261322.

The above-mentioned surfactant is preferably used for the purpose of improving the dispersibility of the inorganic pigment and other additives in the resin and for preventing static electricity. These surfactants can be appropriately selected and used from nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants known in the art. Representative examples of these surfactants are described in detail in JP-A-7-261322.

In the present invention, in order to improve the adhesion of the waterproof resin coating layer to the base paper, it is preferable to add an acid-modified thermoplastic resin, particularly an acid-modified polyolefin resin, to the waterproof resin coating layer. . The above acid-modified polyolefin resin is, for example, a resin obtained by graft-modifying a polyolefin resin with unsaturated carboxylic acids, and specifically, a graft-modified polyethylene resin, a graft-modified polypropylene resin and a graft-modified ethylene copolymer resin. Can be mentioned. Representative examples of these acid-modified thermoplastic resins are described in detail in JP-A-7-261322.

The water-resistant resin coating layer is formed on the paper substrate by a sequential laminating method or a laminating method using a foot block type, multi-manifold type or multi-slot type multi-layer extrusion die.

The shape of the multi-layer extrusion die is generally a T die, a coat hanger die, etc., and is not particularly limited. The exit temperature of the heat-resistant extrusion of water-resistant resin is usually 2
80 ° C to 340 ° C, particularly preferably 310 ° C to 330 ° C
Is. Further, it is preferable that the paper base is subjected to an activation treatment such as a corona discharge treatment, a flame treatment, and a glow discharge treatment before the resin is coated on the paper base.

The coating thickness of the waterproof resin coating layer is preferably 5 μm to 100 μm, and particularly preferably 10 μm to 40 μm on the side where the recording layer is coated. The opposite surface preferably has a thickness of 5 μm to 50 μm, particularly preferably 5 μm to 30 μm. Further, the resins of the water resistant resin coating layer formed on the back surface and the front surface are preferably of the same kind.

(Undercoat layer) As the white pigment contained in the undercoat layer, titanium dioxide, barium sulfate, lithopone, alumina white, calcium carbonate, silica white, antimony trioxide, titanium phosphate, zinc oxide, lead white and gypsum. Etc. can be used. Of these, titanium dioxide is preferable. The titanium dioxide may be rutile type or anatase type, and may be produced by any of the sulfate method and chloride method. Also,
The average particle size of the white pigment is 0.1 μm to 1.0 μm.
If m, all are effective, but among them, those having an average particle size of 0.2 μm to 0.5 μm are preferable.

The mass content of the white pigment contained in the undercoat layer is preferably 50% or more, particularly 60%.
The above is preferable.

The coating amount of the white pigment contained in the undercoat layer is preferably 0.5 to 10 g / m ² , and particularly 1 to 4 g.
/ M ² is preferred.

As the hydrophilic colloid component contained in the undercoat layer, any hydrophilic colloid-forming material usually used in photographic materials can be used. For example, natural polymer compounds such as gelatin and synthetic polymers such as polyvinyl alcohol and polyvinylpyrrolidone can be mentioned, and gelatin is particularly preferable. As the gelatin, so-called lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin and one group capable of reacting with an amino group, an imino group, a hydroxyl group or a carboxyl group as a functional group contained in a gelatin molecule are included. Gelatin derivative treated or modified, or a reagent that increases the carboxyl group on the gelatin side chain, such as phthalic anhydride, succinic anhydride, phthalated gelatin treated with trimellitic anhydride, succinated gelatin, Any of those commonly used in the art such as modified gelatin such as trimellitated gelatin can be used.

In the undercoat layer, a surfactant as a coating aid, a hardener, a dye, an antifoggant, a pH adjusting agent, an antiseptic, a defoaming agent, a viscosity adjusting agent or a fluorescent brightening agent. Etc. can be added.

The solvent used for the undercoat layer is preferably a mixed solvent of water and alcohol. Examples of the alcohol include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol and the like. Among these, it is preferable to use methanol. The mixing ratio of water and alcohol is 90:10 to 10: 9 by mass.
0 is preferable, and 70:30 to 30:70 is particularly preferable.

The method of applying the undercoat layer on the paper substrate provided with the water resistant resin coating layer by the above-mentioned method is generally well known, for example, dip coating method, air knife coating method, curtain coating method. Any method such as a roller coating method may be used. Before applying the undercoat layer, an activation treatment such as corona discharge treatment or flame treatment can be performed.

According to the method for producing a recording material support of the present invention, the wet coating amount at the time of applying the undercoat layer needs to be 20 g / m ² or less. More preferably, it is 10 g / m ² or less. Wet coating amount is 2
By setting the amount to 0 g / m ² or less, the drying load can be reduced in the drying step after the application of the undercoat layer as compared with the conventionally known liquid formulation, and as a result, the production efficiency of the recording material support can be improved. Can be improved.

The coating amount of the hydrophilic colloid contained in the undercoat layer is preferably 1.0 g / m ² or less, and particularly preferably 0.7 g / m ² or less. When the coating amount of the hydrophilic colloid is 1.0 g / m ² or less, the drying property after development is adversely affected when the recording material support according to the present invention is used in a silver halide photographic light-sensitive material or the like. The merit of not giving is obtained.

The drying conditions after coating the undercoat layer vary depending on the drying method, the solvent contained in the coating liquid, the thickness of the coating film, etc., but the drying temperature is preferably 50 to 120 ° C., 60
-100 ° C is more preferable.

In the present invention, the step of forming the water-resistant resin coating layer on the paper substrate and the step of applying the undercoat layer are characterized by being a continuous continuous step without interposing a winding step or the like. By continuously performing the two steps, it is possible to improve the production efficiency of the recording material support.

When the support for recording materials according to the present invention is used in a silver halide photographic light-sensitive material, a silver halide emulsion layer or the like is provided on the undercoat layer. The silver halide emulsion is usually one which has been physically ripened, chemically ripened and spectrally sensitized. The additives used in such a process are Research Disclosure No. 17643, same N
o. 18716 and the same No. No. 307105, and the corresponding portions are summarized in Table 1 below.

[0040]

[Table 1]

In the light-sensitive material, two or more kinds of emulsions having different characteristics of at least one of the grain size, grain size distribution, halogen composition, grain shape and sensitivity of the photosensitive silver halide emulsion are mixed in the same layer. Can be used. For example, the grain-fogged silver halide grains described in U.S. Pat. No. 4,082,553, U.S. Pat. No. 4,626,498 and JP-A-59-
The fogged silver halide grains and colloidal silver described in JP-A 214852 can be preferably used for the photosensitive silver halide emulsion layer and / or the substantially non-photosensitive hydrophilic colloid layer.

The fogged silver halide grain inside or on the surface means a silver halide grain which enables uniform (non-imagewise) development regardless of the unexposed portion and exposed portion of the light-sensitive material. Say that. A method for preparing a silver halide grain whose inside or surface is fogged is described in US Pat. No. 4,626,4.
No. 98 and Japanese Patent Laid-Open No. 59-214852. The silver halide forming the inner core of a core / shell type silver halide grain in which the inside of the grain is fogged is
They may have the same halogen composition or different halogen compositions.

As the silver halide whose inside or surface is fogged, any of silver chloride, silver chlorobromide, silver iodobromide and silver chloroiodobromide can be used. The grain size of these fogged silver halide grains is not particularly limited, but the average grain size is preferably 0.01 to 0.75 μm, and particularly preferably 0.05 to 0.6 μm. Further, the particle shape is not particularly limited, and regular particles may be used. The emulsion may be a polydisperse emulsion, but is preferably monodisperse (in which at least 95% of the mass or number of silver halide grains has a grain size within ± 40% of the average grain size).

The coated silver amount is preferably 6.0 g / m ² or less, and particularly preferably 4.5 g / m ² or less. A protective layer is provided on the emulsion layer as usual,
Slit into the product.

The support for recording materials of the present invention is not only a support for silver halide photographic light-sensitive materials but also a support for various printer papers such as sublimation printers, thermal transfer printers, thermal printers or ink jet printers. Can be used.

[0046]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.
In the following examples,% means mass% unless otherwise specified. [Example 1] (Preparation of undercoat layer) A liquid having the following formulation was dispersed in water using a Dynomill disperser to obtain a titanium dioxide aqueous dispersion having an average particle diameter of 0.35 µm. <Aqueous Titanium Dioxide Dispersion> 2.92 parts by mass of ion-exchanged water 15% solution of polyvinyl alcohol (polymerization degree: 500, saponification degree: 90%) 4.00 parts by mass 5% solution of sodium dodecylbenzenesulfonate 0.30 parts by mass Rutile type titanium dioxide (R780 manufactured by Ishihara Sangyo Co., Ltd.) 4.80 parts by mass

Using the aqueous titanium dioxide dispersion, an undercoat layer coating solution was prepared by the following formulation. <Undercoat layer coating liquid> Ion-exchanged water 2.51 parts by mass Methanol 11.43 parts by mass 40% solution of gelatin (PAGI method jelly strength 20 g) 6.01 parts by mass Titanium dioxide aqueous dispersion 20.06 parts by mass

(Production of Support for Recording Material) Basis Weight 170 g
/ M ² of the base paper is laminated with polyethylene on the side opposite to the side on which the recording layer is applied, and subsequently on the side on which the recording layer is applied, polyethylene containing 10% by mass of anatase type titanium dioxide is laminated at a thickness of 30 g / m ^2. A recording material having an undercoat layer containing a white pigment (titanium dioxide) and a hydrophilic colloid component, which is subsequently applied with the undercoat layer coating solution using a gravure coater so that the wet coating amount is 10 g / m ^2. A support was obtained. At this time, the coating amount of the hydrophilic colloid was 0.86 g / m ² .

(Formation of Recording Layer) A photographic color photographic paper was prepared by coating a photographic emulsion layer on the undercoat layer formed on the above-mentioned recording material support. The photographic emulsion layer is described in paragraph No. [016] of JP-A 2000-352805.
8] to [0196] and formed in the same manner.

[Examples 2 to 9 and Comparative Examples 1 and 2] A support for a recording material was prepared in the same manner as in Example 1 except that the coating solution for the undercoat layer was changed to the formulation shown in Table 2 below. It was made.

[0051]

[Table 2]

Further, a photographic color photographic paper was prepared in the same manner as in Example 1 by using the produced recording material support.

The drying load during the production of the recording material support was evaluated. In addition, using the color photographic printing paper obtained by the above-mentioned method, the sharpness and the dry load after the development processing were evaluated. (Evaluation of Drying Load during Production of Support for Recording Material) The drying load during production of the support for recording material was evaluated by the time required for drying at a drying temperature of 70 ° C. A: Within 30 seconds. ○: Within 1 minute. Δ: Within 2 minutes X: 2 minutes or more.

(Sharpness Evaluation) The sharpness evaluation is performed according to T.I. H. Edited by James “THE THEORY
OFTHE PHOTOGRAPHY PROCESS
S 4th edition "p. 526, the MT value was obtained, and the sharpness was compared and evaluated.
The value means that the closer the value is to 1.0, the better the sharpness, and the less blurring and blurring of the image at the time of printing. A: 0.7 or more. ◯: 0.6 or more. Δ: 0.5 or more. X: Less than 0.5.

(Evaluation of Drying Load After Development) The degree of drying of the surface of the photographic paper after the development was evaluated. ◎: Satisfactory ○: Satisfied. Δ: Acceptable X: Not satisfied.

The evaluation results are shown in Table 3 below.

[0057]

[Table 3]

From Table 3, it can be seen that the drying load during the production of the support and after the development treatment is superior in Examples as compared with Comparative Examples. Further, although the coating amount of titanium dioxide in the example was smaller than that in the comparative example, the same effect as to the sharpness could be obtained.

[0059]

According to the present invention, it is possible to provide a method for producing a support for recording materials, which is capable of continuously carrying out the steps of coating a paper substrate with a waterproof resin and applying the undercoat layer.

Claims (4)

[Claims] 1. A water resistant resin coating layer is provided on both sides of a paper substrate, and an undercoat layer containing a white pigment and a hydrophilic colloid component is provided on the water resistant resin coating layer on the side where a recording layer is applied. A method for producing a support for a recording material, wherein a wet coating amount when applying the undercoat layer is 20 g / m ² or less, and at least from the lamination step of the waterproof resin coating layer, the undercoat layer The method for producing a support for recording material, wherein the steps up to the coating step are continuously performed. 2. The method for producing a recording material support according to claim 1, wherein the coating amount of the hydrophilic colloid contained in the undercoat layer is 1.0 g / m ² or less. 3. The mass content of the white pigment contained in the undercoat layer is 50% or more.
Or the method for producing the support for recording material according to item 2. 4. The method for producing a support for recording materials according to claim 1, wherein the solvent of the coating liquid for the undercoat layer is a mixed solvent of water and alcohol.