JP2002294599A - Support for image material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-coated paper type support for an image material having good adhesion of a sheet of base paper to resin layers and capable of carrying out high-speed extrusion processing with good peelability of the resin layers from a cooling roll when the sheet of base paper is coated with the resin layers in relation to the resin-coated paper type support for the image material having both surfaces of the sheet of base paper coated with the resin layers. SOLUTION: This support for the image material is characterized in that a part of at least either of the resin layers to be in contact with the paper substrate is coated by co-extrusion coating and the melting point of the resin constituting the lowermost layer (the side of the paper substrate) thereof is lower than the melting point of the resin constituting the topmost layer (the side opposite to the side of the paper substrate) by >=5 deg.C in the support for the image material in which both the surfaces of the paper substrate consisting essentially of a natural pulp are coated with a plurality of resin layers composed of a resin composition consisting essentially of a polyethylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated paper-type image material support in which both sides of a paper substrate (hereinafter sometimes abbreviated as base paper) are coated with a resin layer. The present invention relates to a resin-coated paper-type image material support which has good adhesiveness between paper and a resin layer, has good releasability from a cooling roll when coating the resin layer, and is capable of high-speed extrusion coating. Things.

[0002]

2. Description of the Related Art An image material generally comprises a support for an image material and an image forming layer provided on the support. For example, a silver halide photographic material, an ink jet recording material, a heat transfer type thermal transfer recording image-receiving material, a heat-sensitive recording material, a light- and heat-sensitive recording material, and the like are each provided on a support for an image material, a silver halide photographic component layer, an ink image-receiving layer, It is provided with an image forming layer such as a heat transfer type thermal transfer recording image receiving layer, a thermosensitive coloring layer, a photosensitive thermosensitive coloring layer, and auxiliary functional layers such as an undercoat layer, a protective layer, and a back layer, if necessary. In particular, as the silver halide photographic constituting layer, a silver halide photographic emulsion layer, a protective layer, an undercoat layer, an intermediate layer or a color mixing prevention layer,
It is composed of an antihalation layer or a filter layer, an ultraviolet absorbing layer, a back layer and the like, and combinations thereof.

Heretofore, resin-coated paper-type supports in which a base paper surface for an image material support is coated with a resin capable of forming a film are well known. As a support for a resin-coated paper type photographic material for use in silver halide photographic materials, for example, Japanese Patent Publication No. 55-12584 discloses a base paper coated with a resin capable of forming a film, preferably a polyolefin resin. In addition, a technique for a support for a photographic material has been disclosed. U.S. Pat. No. 3,501,298 discloses a technique for a photographic material support in which both sides of a base paper are coated with a polyolefin resin. Further, since the rapid photographic development processing method of silver halide photographic materials was applied, supports for photographic materials in which both sides of a base paper were coated with a polyethylene resin have been mainly put to practical use for photographic printing paper. If necessary, the resin layer on the side on which one of the image forming layers is provided usually contains a titanium dioxide pigment for imparting sharpness.

Further, US Pat. No. 4,774,224 discloses that a resin coating has a surface roughness of 7.5 microinch-A.
A thermal transfer recording image receiving element has been proposed which has, as a support, a resin-coated paper having a size of A or less, in particular, a polyethylene resin-coated paper in which the surface of a base paper is coated with a polyethylene resin. Also,
JP-A-63-307979 discloses a technique relating to an ink jet recording sheet having a resin-coated paper as a support.

However, a resin-coated paper-type image material support in which the surface on which the image forming layer is provided of a base paper, particularly a base paper mainly composed of natural pulp, is coated with a resin layer still has some serious problems. In fact, there are still many problems and satisfactory results have not yet been obtained.

First, a resin-coated paper type image material support is formed by pressing a molten resin extruded into a film from a slit die onto a paper base between a pressure roll and a cooling roll,
It is manufactured through the process of peeling after being cooled by a cooling roll. However, conventionally, when the production speed is increased, there is a problem that the adhesiveness between the base paper and the resin layer is deteriorated.

[0007] Poor adhesion between the paper substrate and the resin layer causes not only a problem that the resin layer is unexpectedly peeled off during production, but also causes a problem.
For example, in the case of a resin-coated paper-type photographic support having insufficient adhesion between the base paper and the surface resin layer, the surface resin layer is formed during the processing for forming a silver halide photographic image of the silver halide photographic material having the support. If the surface resin layer is peeled off, the developing solution penetrates the base paper during development processing and causes color contamination, resulting in complete quality value. There was a problem that it would not be. Furthermore, when the running speed of the base paper during the production of the support for the image material is increased, the cooling of the molten resin extruded from the slit die in the cooling roll portion is insufficient, and the molten resin is not solidified completely. In order to peel off, the place where the adhesiveness has weakened partially peels off from the paper substrate, making it unsuitable as a support for image materials. Thus, the problem of the adhesiveness between the base paper and the resin layer is as follows. The higher the running speed of the base paper during the production of the resin-coated paper-type photographic support, the more the tendency tends to be significant.

Secondly, in the production of a resin-coated paper type image material support, the molten resin is pressed between a pressure roll and a cooling roll on a paper substrate, and is peeled after being sufficiently cooled by the cooling roll. Conventionally, when the production speed is increased, the releasability from the cooling roll (hereinafter, sometimes abbreviated as releasability) deteriorates, and step-like unevenness in the width direction occurs. For this reason, the surface quality of the resin-coated paper is impaired, which makes an image material requiring an excellent surface quality when an emulsion is coated unsuitable.

As a countermeasure against this, various methods have been proposed so far, and as one of them, a method in which various release agents are contained in a polyolefin resin has been proposed. For example, bisfatty acid amides described in JP-A-60-176036, polyalkylene glycols described in JP-A-63-30841, fluorine-containing polymers described in JP-A-64-9444, −143748
It has been proposed to improve the releasability by adding various release agents such as an α-olefin-modified silicone described in Japanese Patent Application Laid-Open Publication No. H11-15064. However, in any of these cases, the effect of improvement is insufficient, and when increasing the amount of addition to improve the releasability and suppress the occurrence of peeling unevenness when increasing the production speed, the resin and the base paper are reduced. When the amount of addition was reduced so as to maintain the adhesion between the resin and the base paper, the effect of improving the releasability was reduced, and the releasability could not be improved effectively.

As another method of improving the releasability, use of a finely rough surface described in JP-B-62-19732 or use of a cooling roll in which a fluorine resin described in JP-B-1-24292 is embedded is used. , Furthermore,
No. 249 proposes to use a low-density polyethylene resin having a melting peak of 110 ° C. or higher and a melt index of 5 to 20 g / 10 minutes.

However, even if such a cooling roll or a resin (and an additive) is used, the effect of increasing the production speed is insufficient. In particular, at a speed of 200 m / min or more, the adhesiveness between the paper substrate and the resin layer is deteriorated. Became remarkable.

In order to solve this problem, co-extrusion in which different types of resin can flow on the side contacting the base paper and the side contacting the cooling roll is effective.
JP-A-5241274 and JP-A-7-0720868 have proposed changing the resin temperature or the resin density of the upper layer and the lower layer.

However, when the processing speed is increased, especially at a speed of 200 m / min or more, the adhesiveness between the base paper and the resin layer becomes insufficient, and it is further difficult to achieve compatibility with the releasability between the cooling roll and the resin.

[0014]

Accordingly, an object of the present invention is to provide a resin-coated paper mold in which a paper substrate mainly composed of natural pulp is coated with a resin layer composed of a resin composition mainly composed of a polyethylene resin. A resin for an image material, which has good adhesion between the base paper and the resin layer, and is capable of high-speed extrusion coating with good releasability of the resin layer from the cooling roll when coating the resin layer. It is an object of the present invention to provide a support for a coated paper type image material.

[0015]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found the following present invention. That is, the invention according to claim 1 provides an image material support in which a paper substrate containing natural pulp as a main component is coated with a plurality of resin layers on both sides of a resin composition containing a polyethylene resin as a main component. The resin layer on one side of the resin layer which is in contact with the paper substrate is coated by co-extrusion coating, and the melting point of the resin constituting the lowermost layer (paper substrate side) of the co-extruded resin layers is the lowest. An image material support characterized by having a melting point of at least 5 ° C. lower than the melting point of the resin constituting the upper layer.

According to a second aspect of the present invention, in the co-extruded layer, the resin constituting the lowermost layer in contact with the paper substrate is mainly composed of a low-density polyethylene resin, and the resin has a melting point of 1%.
The image material support according to claim 1, wherein the temperature is from 00 to 115 ° C.

According to a third aspect of the present invention, in the co-extruded layer, the resin constituting the uppermost layer in contact with the cooling roll has a melting point of 120.
The support for an image material according to claim 1, wherein the temperature is −135 ° C.

According to a fourth aspect of the present invention, there is provided the support for an image material according to any one of the first to third aspects, wherein the resin coating layer on the side forming the image forming layer has a layer containing a titanium dioxide pigment. is there.

The invention according to claim 5 is characterized in that a tandem layer containing a titanium oxide pigment is further provided on the co-extruded layer constituting the image forming layer. Support.

Hereinafter, the present invention will be described specifically. The melting point of the resin referred to in the present invention is measured by a DSC method (JIS K7121).

As described above, the present invention provides a high-productivity image material support having good adhesion between a paper substrate and a resin layer and good peeling of the resin layer even when the processing speed is increased. As a result of our intensive studies, we have found that, among the co-extruded layers, the upper layer of the resin layer (hereinafter sometimes abbreviated as the bottom layer) in contact with the paper substrate has a higher crystallization rate than that of the resin. By providing the resin layer (having a high melting point), the resin of the resin layer in contact with the cooling roll (hereinafter, sometimes abbreviated as the uppermost layer) is immediately crystallized, and the crystallization of the paper substrate side resin is delayed more than that. I found what I could do.

The reason that the crystallization of the lowermost layer can be delayed is that when the molten resin is cooled by the cooling roll, it is cooled from the part in contact with the cooling roll. That is, negative heat is applied from the uppermost layer side by the cooling roll, and is cooled by heat conduction from the uppermost layer,
After the molten resin comes into contact with the cooling roll, a temperature gradient is formed in the depth direction of the resin layer, with the uppermost layer being the lowest temperature. As a result, the crystallization of the resin constituting the uppermost layer occurs more rapidly, and the crystallization of the resin of the lowermost layer is delayed as compared with the uppermost layer.

The reason why the adhesiveness is improved by the present invention can be explained as follows. In other words, when a temperature gradient in which the uppermost layer is the lowest temperature is formed in the molten resin layer, the uppermost layer on the cooling roll side is solidified by crystallization, and the lowermost resin still in a molten state is used as an elastic body to form a base paper. Is pressed so as to replace the voids with the resin. This is an important effect of bonding the base paper and the resin layer, known as the anchor effect, and promotes this.

The releasability of the resin layer from the cooling roll depends on the properties of the resin constituting the uppermost layer. Since the uppermost layer in the present invention is made of a resin having a high crystallization speed, the releasability does not deteriorate even at a high processing speed. As described above, according to the present invention, even at a high processing speed, it is possible to achieve both the adhesiveness between the resin layer and the base paper and the peelability between the cooling roll and the resin layer.

In the co-extrusion processing, even if the resin of each layer is the same type, the time required for crystallization can be made different for each layer by providing a difference in the resin temperature. However, in this case, while the resin is extruded from the extruder and passes through the air gap during lamination to the base paper, the temperature gradient between the top and bottom layers decreases sharply, so the extruder uses It is necessary to increase the temperature difference more than necessary. Excessive temperature change of the resin, from the appropriate temperature range of lamination of the resin,
It is not preferable because the operating conditions are deviated.
In the present invention, by using resins having different melting points in the uppermost layer and the lowermost layer, the above-described anchor effect can be effectively obtained without giving a difference in resin temperature in the extruder.

The difference between the melting points of the polyethylene resins constituting the uppermost layer and the lowermost layer of the present invention must be 5 ° C. or more. If the difference is less than 5 ° C., the anchor effect of the lowermost layer by the uppermost layer acting as an elastic body as described above does not function, and it is impossible to obtain sufficient adhesion between the base paper and the resin layer.

According to the present invention, the resin constituting the lowermost layer is mainly composed of a low-density polyethylene resin and has a melting point of 10%.
The melting point of the resin constituting the uppermost layer is preferably from 120 to 135 ° C. If the melting point of the uppermost layer is lower than 120 ° C., the crystallization of the uppermost layer will be delayed, and the removability of the uppermost layer from the cooling roll will be poor. If the melting point of the uppermost layer is higher than 135 ° C., crystallization is promoted and sufficient releasability of the resin from the cooling roll can be obtained, but the curl of the produced image material support increases. However, the amount of resin applied on the opposite side of the base paper due to curling is increased, which is disadvantageous in cost. In addition, it is preferable to use a low-density polyethylene resin for the lowermost layer, but a low-density polyethylene resin is generally very suitable for extrusion coating and has good adhesion to a base paper.

The anchor effect of the lowermost layer of the present invention is that the resins having melting points different from each other by 5 ° C. or more need to be simultaneously laminated on the base paper by co-extrusion. , You can not get the effect.

However, in the case of further tandem processing on the co-extruded layer, use of the same resin as the uppermost layer of the co-extruded layer or low-temperature processing ensures the releasability from the cooling roll even during high-speed processing. can do. The resin temperature during low-temperature processing is preferably in the range of 250 to 300 ° C.

It is effective to add various pigments (masterbatch) to the image forming surface of the image material support. However, even when a pigment or the like is added to the co-extruded layer of the present invention, the uppermost layer is an elastic material. The working bottom anchor effect can be obtained in the same way. However, for the adhesiveness to the base paper, it is preferable that the lowermost layer be made of a resin alone.

Therefore, the pigment can be added to the resin layer on the image forming surface in a layer other than the lowermost layer of the co-extrusion layer or by further providing a tandem layer on the co-extrusion layer. In addition, the surface quality is significantly improved by performing tandem processing, and therefore a combination of the two is more preferable.

Image forms preferably used in the practice of the present invention
For the front resin layer on the side where the layer is to be provided, and the back resin on the opposite side
Low-density polyethylene is used as the polyethylene resin for the layer.
Resin, medium density polyethylene resin, high density polyethylene
Resin, linear low-density polyethylene resin, ultra-low-density polyether
Α- such as Tylene resin, ethylene and propylene, and butylene
Copolymers with olefins, ethylene and acrylic acid,
Copolymers such as ethyl lylate and maleic anhydride
Or a graft copolymer, so-called carboxy-modified poly
Ethylene resin, autoclave type reactor, tube
Poly by high pressure radical polymerization using a bra reactor
Polymerization using ethylene resin and metallocene polymerization catalyst
Polyethylene resin, Ziegler method, Philips
Polymerization using metal catalysts other than metallocene
The produced polyethylene resin and its mixture
Density, melt flow rate (hereinafter JIS)
The melt flow rate specified by K6760 is simply
MFR), molecular weight and molecular weight distribution
It usually has a density of 0.90 to 0.97 g / cm ^Threeof
Range, MFR 0.1 g / 10 min to 50 g / 10 min, good
Preferably, the MFR is 0.3 g / 10 min to 40 g / 10 min.
Can be advantageously used alone or as a mixture.
You.

The polyethylene resin for the back resin layer which is advantageously used in the practice of the present invention has an MFR of 10 g / 10
Min to 40 g / 10 min, preferably 10 g / 10 min to 30
g / 10 minutes, 90% to 65% by mass of high-density polyethylene resin having a density of 0.960 g / cm ³ or more, and MF
R is 0.2 g / 10 min to 3 g / 10 min, preferably
0.2 g / 10 min to 1.5 g / 10 min, density 0.93
A compound resin composition in which a low-density polyethylene resin or a medium-density polyethylene resin of 5 g / cm ³ or less is melted and mixed in advance with 10% by mass to 35% by mass is preferable.
The molecular weight distribution of the low-density polyethylene resin or the medium-density polyethylene resin is preferably such that the fraction having a molecular weight of 500,000 or more is 10% by mass or more, and particularly preferably 12% by mass or more. If the fraction of the resin having a molecular weight of 500,000 or more is less than 10% by mass, molding processability, particularly neck-in, is undesirably large. Here, the molecular weight is 150-C manufactured by Waters (column: GMH-X manufactured by Tosoh Corporation).
LHT 8mmφ × 30cm × 3, solvent: 1,2,2
4-trichlorobenzene, temperature: 135 ° C, flow rate: 1 m
1 / min) obtained by the GPC method using the GPC method.

As the polyethylene resin for the back resin layer used in the practice of the present invention, a compound resin prepared by melting and mixing in advance is preferable. As a method for preparing a compound resin by previously melting and mixing a low-density polyethylene resin or a medium-density polyethylene resin and a high-density polyethylene resin, a simple melt mixing method, a multi-stage melt mixing method, or the like can be used. For example, using an extruder, a twin-screw extruder, a heating roll mill, a Banbury mixer, a pressure kneader, and the like, a predetermined amount of low-density or medium-density polyethylene resin and high-density polyethylene resin, and if necessary, an antioxidant A method of adding various additives such as a lubricant, melting and mixing, and then pelletizing the mixture is advantageously used.

As the slit die used in the present invention, a flat die such as a T-type die, an L-type die and a fishtail type die is preferable, and the slit opening diameter is desirably 0.1 mm to 2 mm. Before coating the resin composition on the base paper, the base paper is preferably subjected to an activation treatment such as a corona discharge treatment or a flame treatment. Further, as described in JP-B-61-42254, a resin layer may be coated on a running base paper after spraying an ozone-containing gas onto a molten resin composition in contact with the base paper. Further, it is preferable that the front and back resin layers are sequentially, preferably continuously, extruded and coated on the base paper by a so-called tandem extrusion coating method. If necessary, the resin layer on the back side may be covered by a multilayer extrusion coating method in which the resin layer has a multilayer structure of two or more layers. The surface resin layer surface of the image material support can be processed into a glossy surface, a finely rough surface described in JP-B-62-19732, a matte surface or a silk surface, and the back resin layer is usually matt. It is preferable to process the surface.

The thickness of the front and back resin layers of the image material support in the present invention is not particularly limited, but the thickness of the front resin layer is preferably in the range of 9 μm to 60 μm. , Preferably in the range of 12 μm to 45 μm.
The thickness of the back resin layer is usefully in the range of 5 μm to 60 μm, but is preferably in the range of 8 μm to 40 μm. Further, it is preferable that the difference in the amount of resin coating between the front and back resin layers be 3 g / m ² or more by reducing the amount of coating of the back resin layer as compared with the front resin layer.

Various additives can be contained in the front and back resin layers of the support for image materials in the present invention. JP-B-60-3430, JP-B-63-11655
No., Japanese Patent Publication No. 1-38291, Japanese Patent Publication No. 1-38292
And white pigments such as titanium oxide, zinc oxide, talc, calcium carbonate, etc., fatty acid amides such as stearamide, arachidic amide, zinc stearate, calcium stearate described or exemplified in JP-A-1-105245 and the like. Fatty acid metal salts such as aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, and the like, such as hindered phenols, hindered amines, phosphorus compounds, and sulfur compounds described in or exemplified in JP-A-1-105245. Various antioxidants, cobalt blue, ultramarine, celian blue,
Blue pigments and dyes such as phthalocyanine blue; magenta pigments and dyes such as cobalt violet, fast violet and manganese violet;
Various additives such as a fluorescent whitening agent and an ultraviolet absorber described or exemplified in JP-A-54440 can be appropriately combined and contained. These additives are preferably contained as a resin masterbatch or compound. In particular, as a method for incorporating these additives into the compound resin composition for the back resin layer preferably used in the practice of the present invention, a method of pre-adding to a high-density polyethylene resin and a low-density polyethylene resin or a medium-density polyethylene resin is used. Alternatively, a masterbatch which is added at the time of preparing the compound resin or which is added to the resin at a high concentration may be prepared in advance, and this masterbatch may be added to the resin at the time of melt extrusion coating.

The surface of the polyethylene-based surface resin layer on the side of the image material support on which the image forming layer is provided in the present invention can be subjected to activation treatment such as corona discharge treatment or flame treatment. Further, after the activation process, a subbing process as described or exemplified in JP-A-1-102551 and JP-A-1-16635 can be performed.

The pulp constituting the base paper used in the practice of the present invention is disclosed in JP-A-58-37642, JP-A-60-67940, JP-A-60-69649, and JP-A-61-69649. It is advantageous to use appropriately selected natural pulp as described or exemplified in JP-A-35442. Natural pulp is chlorine, hypochlorite,
Condensed-wood pulp, hardwood pulp, softwood-mixed pulp that has been subjected to ordinary bleaching treatment of chlorine dioxide bleaching and alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment with hydrogen peroxide, oxygen, etc., and a combination treatment thereof Wood pulp is used, and various pulp such as kraft pulp, sulfite pulp, soda pulp, and other recycled pulp (waste paper pulp) can be used.

The base paper used in the practice of the present invention can contain various additives during preparation of the stock slurry. Examples of the sizing agent include fatty acid metal salts and / or fatty acids, alkyl ketene dimer emulsions and / or epoxidized higher fatty acid amides, alkenyl or alkyl succinic anhydride emulsions and rosin derivatives described or exemplified in JP-B-62-7534. As a dry paper strength enhancer, anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., as a wet paper strength enhancer, polyamine polyamide epichlorohydrin resin, etc.
Fillers include clay, kaolin, calcium carbonate, titanium oxide, etc .; fixing agents, such as water-soluble aluminum salts such as aluminum chloride and bansulfate; pH adjusting agents, such as caustic soda, sodium carbonate, sulfuric acid, etc. -2
It is advantageous to incorporate color pigments, coloring dyes, fluorescent brighteners and the like described or exemplified in JP-A-04251, JP-A-1-26637 and the like in an appropriate combination.

In the base paper, a composition comprising various water-soluble polymers or hydrophilic colloids or latex, an antistatic agent, and additives is subjected to size press or tab size press, blade coating, air knife coating, or the like. Can be contained by coating. As a water-soluble polymer or a hydrophilic colloid, JP-A-1-26
No. 6537, a starch-based polymer described or exemplified,
Emulsions and latexes such as polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, cellulose-based polymers and the like, petroleum resin emulsions, JP-A-55-4027, JP-A-1
An emulsion or latex of a copolymer containing at least ethylene and acrylic acid (or methacrylic acid) described or exemplified in JP-A-180538, styrene-butadiene-based, styrene-acryl-based,
Vinyl acetate-acrylic, ethylene-vinyl acetate, butadiene-methyl methacrylate-based copolymers and emulsions or latexes of their carboxy-modified copolymers, as antistatic agents, sodium chloride, alkali metal salts such as potassium chloride, Alkaline earth metal salts such as calcium chloride and barium chloride; colloidal metal oxides such as colloidal silica; organic antistatic agents such as polystyrene sulfonate; pigments such as clay, kaolin, calcium carbonate, talc, barium sulfate , Titanium oxide, etc.
It is advantageous to incorporate, as a pH adjuster, hydrochloric acid, phosphoric acid, citric acid, caustic soda and the like, as well as the above-mentioned additives such as coloring pigments, coloring dyes and fluorescent brighteners in an appropriate combination.

In the present invention, the base paper
The density is 0.90 g / cm^Three~ 1.15 g / cm^Three
Is preferable, and 0.95 g / cm^Three~ 1.15 g /
cm ^ThreeIs more preferable, and 1.00 g / cm^Three~ 1.
10g / cm^ThreeIs particularly preferred. The density of the base paper
0.90g / cm^ThreeWhen the value is less than the above, excellent surface smoothness is excellent.
Image material support cannot be obtained and the density of the base paper is
1.15 g / cm^ThreeIf it is larger than the image material and its pre
The problem is that the waist of the client becomes weak. In addition, implementation of the present invention
There is no expiration date for the thickness of the base paper used for
However, its basis weight is 40 g / m^Two~ 250g / m^TwoHas
70g / m^Two~ 220g / m^TwoThings are preferred
No.

In the present invention, various gelatins preferably used for the undercoat layer include lime-treated gelatin, acid-treated gelatin, enzyme-treated gelatin, gelatin derivatives such as gelatin reacted with dibasic acid anhydride. Can be mentioned. In addition, other hydrophilic polymers such as polyvinyl alcohol and starch can be used in combination with gelatin. Further, the pH of the undercoating liquid is not particularly limited, but from the viewpoint of the storability of the photographic material, the pH is
H8 or less is preferable, and pH 7 or less is more preferable.

The coating amount of the undercoat layer in the present invention is not particularly limited, but the coating amount of gelatin is 0.1 g% to 10 wt% of an aqueous coating solution of 1 g / m ^{2 to} 40 g / m ^{2. 2 The} coating is preferably performed, and from the viewpoint of improving the liquid adhering property of the coating solution for the image forming layer and the adhesiveness between the support and the image forming layer, the solid mass is 0.005 g / m ^{2 to} 2.0 g / m ^{2. 2} ranges are preferred, even more preferred range of 0.01 g / m ² to 1.0 g / m ^2, the range of 0.02g / m ² ~0.5g / m ² is particularly preferred.

As a method of providing the undercoat layer on the surface resin layer side, after coating the resin layer on the running base paper surface, the undercoat layer is provided on the resin layer side on which the image forming layer is provided before winding. It is preferred to carry out by a so-called on-machine method in which a liquid is applied and dried to form an undercoat layer. Further, after winding the resin-coated paper, if necessary, after storing the winding, a subbing layer may be newly provided, that is, a so-called off-machine method. Prior to the application of the undercoat layer, the resin surface may be subjected to a corona discharge treatment or another activation treatment such as a flame treatment. Various drying devices such as hot air dryers such as linear tunnel dryers, arch dryers, air loop dryers, sine curve air float dryers, etc., drying devices using infrared rays, heating dryers, microwaves, etc. Can be given. Drying conditions are arbitrary, but generally 40 ° C. to 150 ° C.
C. in seconds to 10 minutes.

The backing resin layer on the side opposite to the side on which the image forming layer of the image material support of the present invention is provided is subjected to an activation treatment such as a corona discharge treatment or a flame treatment. Various back coat layers can be applied. In the back coat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment,
Surfactants and the like can be appropriately combined and contained.

The support for the image material in the present invention is coated with various photographic constituent layers and is used for color photographic paper, black-and-white photographic paper, typesetting photographic paper, copy photographic paper, reversal photographic material, The silver salt diffusion transfer method can be used for various purposes such as negative and positive, and printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. The silver halide photographic emulsion layer may contain a color coupler to provide a multilayer silver halide color photographic constituting layer. Further, a photographic component layer for a silver salt diffusion transfer method can be provided. As a binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic high-molecular substances such as polyvinylpyrrolidone, polyvinyl alcohol and polysaccharide sulfate compounds can be used. Further, the above-mentioned photographic constituent layer can contain various additives. For example, as a sensitizing dye, a cyanine dye, a merocyanine dye, etc., as a chemical sensitizer, a water-soluble gold compound, a sulfur compound, etc., as an antifoggant or stabilizer, a hydroxy-triazolopyrimidine compound, a mercapto-heterocyclic compound, etc. , Hardening agents such as formalin, vinyl sulfone compounds and aziridine compounds, coating aids such as alkylbenzene sulfonates and sulfosuccinate salts, etc. Dye, antistatic agent, pH adjuster,
A fogging agent and a water-soluble iridium compound, a water-soluble rhodium compound, and the like at the time of generation and dispersion of silver halide may be incorporated in an appropriate combination.

The photographic material according to the present invention is subjected to exposure, development, and stoppage according to the photographic material as described in "Photosensitive Materials and Handling Methods" (Kyoritsu Shuppan, Goro Miyamoto, Photographic Technology Course 2). , Fixing, bleaching, and stabilization. Further, the multi-layer silver halide color photographic material may be treated with a developer containing a development accelerator such as benzyl alcohol, thallium salt, phenidone or the like, or may be treated with a developer substantially free of benzyl alcohol. it can.

The support for an image material in the present invention can be used as a support for various thermal transfer recording image-receiving materials by coating various thermal transfer recording image-receiving layers. Examples of the synthetic resin used for the thermal transfer recording image receiving layer include various resins such as a polyvinyl resin, a polystyrene resin, a polyester resin, a polyamide resin, and a polyuric acid resin, and a mixture or copolymer thereof.

In the thermal transfer recording image-receiving layer according to the present invention,
A release agent, a pigment, and the like may be added in addition to the synthetic resin. Examples of the release agent include solid waxes such as polyethylene wax, amide wax, Teflon (registered trademark) powder, fluorine-based and phosphate-based surfactants, and silicone oils. Among these release agents, silicone oil is most preferred. As the silicone oil, an oily substance can be used, but a curable type is preferred. As setting type silicone oil, reaction setting type,
A photo-curing type, a catalyst-curing type and the like can be mentioned, and a reaction-curing type silicone oil is particularly preferable. Examples of the reaction-curable silicone oil include an amino-modified silicone oil and an epoxy-modified silicone oil. The amount of the reactive silicone oil added is 0.1 wt% in the image receiving layer.
-20 wt% is preferred. As the pigment, silica,
Extenders such as calcium carbonate, titanium oxide and zinc oxide are preferred. Further, the thickness of the image receiving layer is 0.5 μm to
It is preferably 20 μm, more preferably 2 μm to 10 μm.

The support for an image material in the present invention can be used as a support for various ink-jet recording materials by coating various ink image-receiving layers. Various binders can be contained in the ink image to improve the drying property of the ink and the sharpness of the image. Specific examples of the binder include lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, gelatin derivatives, and various gelatins such as phthalic acid, maleic acid, and gelatin reacted with an anhydride of a dibasic acid such as fumaric acid. , Ordinary polyvinyl alcohols of various saponification degrees, carboxy-modified, cationic-modified and amphoteric polyvinyl alcohols and their derivatives, starches such as oxidized starch, cationized starch, etherified starch, and cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose , Polyvinyl pyrrolidone, polyvinyl pyridium halide, sodium polyacrylate, methacrylic acid copolymer salt, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether and maleic anhydride Polymers, styrene / maleic anhydride copolymers and salts thereof, synthetic polymers such as polyethyleneimine, styrene / butadiene copolymers, conjugated diene copolymer latexes such as methyl methacrylate / butadiene copolymer, polyvinyl acetate , Vinyl acetate
Vinyl acetate polymer latex such as maleic acid ester copolymer, vinyl acetate / acrylic acid ester copolymer, ethylene / vinyl acetate copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, ethylene / acrylic acid ester Acrylic polymer or copolymer latex such as copolymer, styrene-acrylate copolymer, vinylidene chloride copolymer latex, etc., or functional group-containing monomer such as carboxyl group of these various polymers Functional group-modified polymer latex, melamine resin, aqueous adhesive such as thermosetting synthetic resin such as urea resin and polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral, Synthetic resin adhesive such as alkyd resin, etc. No. 4906, JP-A-3-28138
No. 3, Japanese Patent Application No. 4-240725, and the like, and inorganic binders such as alumina sols and silica sols described or exemplified in the official gazettes. These can be used alone or in combination.

The ink receiving layer of the ink jet recording material according to the present invention may contain various additives in addition to the binder. For example, as a surfactant, an anionic surfactant such as a long-chain alkyl benzene sulfonate, a long-chain, preferably a branched alkyl sulfosuccinate, a polyalkylene oxide of a long-chain, preferably a branched alkyl group-containing phenol. Nonionic surfactants such as ethers and polyalkylene oxide ethers of long-chain alkyl alcohols;
No. 303, U.S. Pat. No. 3,589,906, etc., such as fluorinated surfactants such as .gamma.-aminopropyltriethoxysilane, N-.beta. (Aminoethyl) .gamma.
Silane coupling agents such as aminopropyltrimethoxysilane, and polymer hardeners such as active halogen compounds, vinylsulfone compounds, aziridine compounds, epoxy compounds, acryloyl compounds, and isocyanate compounds; Kaihei 1-1255
P-hydroxybenzoic acid ester compounds, benzisothiazolone compounds, isothiazolone compounds, and the like described or exemplified in JP-A No. 1 (Kokai) No. 63-204251, JP-A-1-266637 and the like or the colored pigments described or exemplified in JP-A No. 1-266537, Colored dyes, fluorescent whitening agents, etc., sodium methanesulfonate and sodium P-toluenesulfinate as yellowing inhibitors, benzotriazole compounds having a hydroxy-di-alkylphenyl group at the 2-position as ultraviolet absorbers, JP-A No. 1-1 as an antioxidant
No. 05245 or examples of polyhindered phenol compounds such as starch or barium sulfate, silicon dioxide or other organic or inorganic fine particles having a particle size of 0.2 μm to 5 μm, such as polyhindered phenol compounds. Appropriate combinations of organopolysiloxane compounds described or exemplified in gazettes and the like, and various additives such as caustic soda, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, octyl alcohol, and silicon-based antifoaming agents as a pH adjuster Can be included.

[0053]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited to the examples.

Example 1 Fiber length of pulp after beaten hardwood bleached kraft pulp (JAPAN TAPPI paper pulp test method No. 52)
-89, which was beaten to a length-weighted average fiber length of 0.55 mm as measured in accordance with "Paper and Pulp Fiber Length Test Method", and then cationized starch was added to 100% by mass of the pulp. 3% by mass, anionized polyacrylamide 0.2% by mass, alkyl ketene dimer emulsion (as ketene dimer component) 0.4% by mass, polyamide epichlorohydrin resin 0.4% by mass and an appropriate amount of fluorescent whitening agent,
A blue dye and a red dye were added to prepare a stock slurry. Thereafter, the stock slurry is placed on a fourdrinier paper machine running at 200 m / min to form a web while giving appropriate turbulence, and 15 to 100 kgf / c in a wet part.
After performing a three-stage wet press in which the linear pressure was adjusted in the range of m, a smoothing roll was used, and in a subsequent drying part, a two-stage tension press in which the linear pressure was adjusted in the range of 30 to 70 kgf / cm. And then dried. Thereafter, during the drying, 25 g / size press liquid composed of 4% by mass of carboxy-modified polyvinyl alcohol, 0.05% by mass of a fluorescent whitening agent, 0.002% by mass of a blue dye, 4% by mass of sodium chloride and 92% by mass of water. m ² size was pressed, the finally obtained base paper moisture is dried to be 8 mass% in absolute dry moisture treated machine calender at a linear pressure of 70 kgf / cm, a basis weight of 170 g / m ^2, a density Is 1.04 g / c
A base paper for an image material support having m ³ , a film thickness unevenness Rpy of 200 mV, and a front-side center surface average roughness SRa of 1.15 μm was produced.

Next, the base paper surface (back surface) opposite to the side on which the image forming layer is provided is subjected to corona discharge treatment, and the following resin composition is applied to the back surface at a resin temperature of 315 ° C. and a resin thickness of 20 μm. Melt extrusion coating was performed at a paper traveling speed of 200 m / min. At this time, as the cooling roll, the center surface average roughness SRa of the back layer surface after coating the following back layer was 1.
Those having a roughness of 15 μm were used. The cooling roll used was a cooling roll roughened by a liquid honing method and operated at a cooling water temperature of 12 ° C. [Blending of resin composition for back surface] High-density polyethylene resin (density 0.967 g / cm ³ , MFR = 15 g / 10
Min) and 70% by mass of low-density polyethylene resin (density 0.9
30 g / m 2 (24 g / cm ³ , MFR = 0.6 g / 10 min) using a melt extruder, which was previously melt-mixed and used as pellets.

Subsequently, after the surface of the base paper was subjected to corona discharge treatment, the low-density polyethylene resin composition shown in Table 1 was applied to the surface of the base paper at a resin temperature of 315 such that the layer configuration shown in Table 2 was obtained.
The composition was melt-extruded and coated to a thickness of 28 μm at a running speed of the base paper of 200 m / min. In addition, samples 1 to 3 are extruded only the lowermost layer first, and only the uppermost layer is further extruded and coated thereon, that is, a so-called tandem extrusion coating method, and the other samples are extruded and coated simultaneously with the lowermost layer and the uppermost layer. Co-extrusion coating was performed (the resin temperature of the uppermost layer and the lowermost layer was constant). The surface of the resin layer was processed to a glossy surface.

Further, after processing the front and back resin layers and before winding, the back resin layer surface of the resin-coated paper is subjected to a corona discharge treatment.
The following coating solution for the back layer was applied on-machine. As dry mass, colloidal silica: styrene latex =
The coating liquid for the back layer containing 1: 1 and further containing 0.021 g / m ² of sodium polystyrene sulfonate and an appropriate amount of a coating aid as a latex component (calculated on a solid weight basis).
Coating was performed at a coating amount of 21 g / m ² .

After coating the back layer and before winding the resin-coated paper, the front resin surface is subjected to a corona discharge treatment to obtain 1.2 g of lime-treated gelatin and low molecular weight gelatin (manufactured by Nitta Gelatin Co., Ltd.). P-3226), 0.3 g of a 10% by mass methanol solution of butyl paraoxybenzoate, and 0.45 g of a 5% by mass mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt. An undercoating solution having a formulation adjusted to 100 g was uniformly applied on-machine so as to have a gelatin coating amount of 0.06 g / m ² to obtain a support for an image material.

[Evaluation of Adhesiveness between Base Paper and Resin Layer] As a method for evaluating the adhesiveness between the base paper and the resin layer of the image material support, each material was heated at a constant temperature and humidity of 50 ° C. and 60% RH. After one day of storage, the base paper layer and the resin layer of the sample were separated, and the adhesion between the base paper and the resin layer was evaluated by measuring the area ratio of the base paper layer adhered to the separated resin layer. did. The evaluation criteria are as follows. A: The area ratio is 100%, and the adhesiveness is very good. ：: The area ratio is 90% or more, and the adhesiveness is good. Δ: The area ratio is 80% or more, and the adhesiveness is slightly poor.
No problem in practical use. ×: The area ratio is less than 80%, the adhesion is poor, and there is a practical problem.

[Evaluation of Peeling Property from Cooling Roll] The peeling property of the image material support from the cooling roll was evaluated by the degree of occurrence of unevenness in the cooling roll peeling. As an evaluation method, the resin surface of the image material support and the image forming layer as a color photographic paper after the application of the emulsion were observed obliquely and visually judged. The evaluation criteria are as follows. A: No or very little peeling unevenness occurs. ：: Little occurrence of uneven peeling. Δ: The occurrence of peeling unevenness is slightly large, but there is no practical problem. ×: There are many occurrences of peeling unevenness, and there is a problem in practical use.

[Nashiji] Contact type three-dimensional surface roughness meter and 3
As a dimensional roughness analyzer, SE-3 manufactured by Kosaka Laboratory Co., Ltd.
Using an AK type machine and a SPA-11 type machine, at a cutoff value of 0.8 mm, the length in the X-axis direction is 20 mm, the length in the Y-axis direction is 8 mm, and therefore, under the condition that the sample area is 160 mm ² , 500 samplings for axial data processing
The operation was performed in the Y-axis direction, and the grade was evaluated with a depression of 1 μm or more as a satin finish from a surface roughness diagram obtained by drawing 16 lines. The evaluation criteria are as follows. A: Good with almost no satin formation. ：: The appearance of satin is small and good. Δ: The occurrence of satin was somewhat large, but not practically problematic. ×: There is a lot of pears and there is a practical problem.

Table 1 shows a list of the resins used.

[0063]

[Table 1]

Table 2 shows the results of the obtained adhesiveness and the releasability of the cooling roll. The melting point difference in Table 2 is a value obtained by subtracting the melting point of the lowermost layer from the melting point of the uppermost layer.

[0065]

[Table 2]

(Note 1) ○ in Table 2 represents a sample according to the present invention.

As is clear from the results shown in Table 2, the support for the image material manufactured by simultaneously extruding a resin having a melting point difference of 5 ° C. or more between the uppermost layer and the lowermost layer by a co-extrusion coating method comprises a base paper and a resin layer. It can be seen that this is a support for an image material which has good adhesiveness to the film and can be subjected to high-speed extrusion coating. In spite of the fact that Samples 1 to 3 had a melting point difference of 5 ° C. or more, they were tandem-extruded and coated, so that the anchoring effect did not occur due to the uppermost layer where crystallization had progressed. I couldn't get it. In the support for an image material of the present invention, the larger the difference in melting point, the better the adhesion to the base paper.

Example 2 A sample was prepared and evaluated under the same conditions as in the sample 4 of Example 1 except that the resin used was changed.

Table 3 shows the obtained results. The melting point difference in Table 3 is a value obtained by subtracting the melting point value of the lowermost layer from the melting point value of the uppermost layer.

[0070]

[Table 3]

(Note 2) In Table 3, the circles in Note 2 are samples representing the scope of Claim 2.

As is clear from the results in Table 3 (Note 2), even if the difference in melting point between the uppermost layer and the lowermost layer is 5 ° C. or more, if the melting point of the lowermost layer is not in the range of 100 ° C. to 115 ° C., it is sufficient. It turns out that adhesiveness cannot be obtained. Therefore, there is a melting point difference of 5 ° C. or more (the uppermost layer−the lowermost layer), and the melting point of the lowermost layer is 100 to 1
Coextrusion using a resin at 15 ° C. enables high-speed extrusion coating with good adhesion between the base paper and the resin layer.

(Note 3) In Table 3, the circles in Note 3 are samples representing the scope of Claim 3.

As is clear from the results in Table 3 (Note 3), even if the difference in melting point between the uppermost layer and the lowermost layer is 5 ° C. or more, if the melting point of the uppermost layer is not 120 to 135 ° C., sufficient cooling roll peeling can be performed. It can be seen that the property cannot be obtained. Therefore, melting point difference of 5 ° C
(Top layer-bottom layer), and the melting point of the bottom layer is 100 ~
By co-extrusion using 115 ° C resin with the uppermost layer having a melting point of 120-135 ° C, high-speed extrusion coating that achieves both adhesion between the base paper and the resin layer and releasability between the cooling roll and the resin layer becomes possible. Become.

Example 3 A sample was prepared and evaluated under the same conditions as those for the sample 4 of Example 1 except that the resin used was changed.

Table 4 shows the obtained results. The melting point difference in Table 4 is a value obtained by subtracting the melting point value of the lowermost layer from the melting point value of the uppermost layer.

[0077]

[Table 4]

(Note 4) ○ in Table 4 represents a sample according to the present invention.

As is evident from the results in Table 4, even if the resin layer contains a titanium dioxide pigment, the adhesiveness and the releasability of the cooling roll are improved by giving a difference in melting point between the resin in the uppermost layer and the resin in the lowermost layer. You can see that. However, the lower layer does not contain titanium dioxide, the better the adhesiveness.

Example 4 Sample No. 23 to 25 are sample Nos. Of Example 3. 16 ~
18 was prepared in the same manner. Sample No. 26 to 31 are sample Nos. Of Example 3. Further, a tandem layer was provided on the uppermost layer of Nos. 20 to 22. 23 to 25.

Table 5 shows the obtained results. The melting point difference in Table 5 is a value obtained by subtracting the melting point of the lowermost layer from the melting point of the uppermost layer of co-extrusion.

[0082]

[Table 5]

As is clear from the results shown in Table 5, even when a tandem layer is provided on the co-extrusion layer and a titanium oxide pigment or the like is added, the adhesion to the base paper and the releasability from the cooling roll are compatible. A high-productivity image material support can be obtained. In the case of the co-extruded layer alone, it is preferable not to add a pigment to the lowermost layer in order to secure adhesion to the base paper, and the pigment is concentrated in the upper layer side, which adversely affects the operation surface. However, if the tandem layer is added to the co-extrusion layer and the pigment is added to this layer, the problem of the pigment concentration in the upper layer of the co-extrusion can be solved. Further, it can be seen that tandem processing significantly improves the surface quality of the support for image materials. Usually, when laminating a resin, the surface quality tends to deteriorate as the processing speed increases. In particular, the occurrence of a satin finish whose surface is roughened by a crater-shaped depression increases significantly as the processing speed increases. When tandem processing is used, the occurrence of satin is significantly reduced, so that good surface quality can be obtained even when laminating at high speed. However, in order to maintain the cooling roll releasability of the tandem layer, it is necessary that the resin used for this layer has a property close to that of the resin of the co-extrusion uppermost layer.

[0084]

According to the present invention, in a multilayer resin-coated image material support, the difference between the melting point of the lowermost resin and the melting point of the uppermost resin is not less than a specified value, so that the adhesion between the paper substrate and the resin layer is improved. And a support for an image material free from problems caused by resin releasability.

Continued on the front page F-term (reference) 2H023 FA04 FA06 FA13 2H086 BA21 BA24 BA32 2H111 CA23 CA30 CA31 4F100 AB12B AB12C AB12D AB12E AJ04A AK04B AK04C AK04D AK04E AK06B AK06C AK06D AK06 BA05 AL05 BA05 AL05 BA10E BA26 CA13 DG01 DG10A EH20B EH20C EH20D EH20E EH23B EH23C EH23D EH23E EJ19 EJ192 EJ86 EJ862 GB90 JA04B JA04C JA04D JA04E JL11 YY00B YY00C YY00D YY40 AG06 AG72 AG72 AG72

Claims (5)

[Claims] 1. A support for an image material, in which a paper substrate mainly composed of natural pulp is coated with a plurality of resin layers composed of a resin composition composed mainly of a polyethylene resin on both sides of at least one surface of the paper substrate. A layer in contact with the paper substrate of the resin layer is coated by co-extrusion coating,
And the melting point of the resin constituting the lowermost layer of the co-extruded resin layers is 5 ° C. lower than the melting point of the resin constituting the uppermost layer.
A support for an image material, wherein the support is low. 2. The resin constituting the lowermost layer of the co-extruded layer, which is in contact with the paper substrate, is mainly composed of a low-density polyethylene resin, and has a melting point of 100 to 115 ° C. The support for an image material according to claim 1, wherein 3. The image material support according to claim 1, wherein the melting point of the resin constituting the uppermost layer of the co-extruded layer, which is in contact with the cooling roll, is 120 to 135 ° C. 4. The support for an image material according to claim 1, wherein a titanium oxide pigment is contained in a portion of the resin coating layer constituting the image forming layer other than the lowermost layer of the co-extrusion. body. 5. The image material according to claim 1, wherein a tandem layer containing a titanium oxide pigment is further provided on the co-extruded layer on the side forming the image forming layer. Support.