JPH11109559A - Supporting body for image material, and image material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good travelling property, winding property, cutting accuracy and cutting property by specifying the center face average roughness of the back layer surface of a paper base measured by a probe-type three-dimensional surface roughness meter with a specified cutoff value. SOLUTION: A resin layer containing a film-forming resin is applied on the surface of a paper base essentially comprising natural pulp opposite to the surface where an image forming layer is to be formed, and the resin layer is roughened. Further a back layer is applied on the resin layer. The center face average roughness (SRa1) on the surface of the back layer in the paper making direction measured by a probe-type three-dimensional surface roughness meter with 0.8 mm cutoff is specified to 1.35 to 2.35 μm. Further, the center face average roughness (SRa2) on the surface of the back layer in the paper making direction measured by a probe-type three-dimensional surface roughness meter with 0.025 mm cutoff is specified to 0.20 to 0.45 μm. The resin layer is roughened by using a roughened cooling roll as a cooling roll when the resin compsn. is applied by melt-extruding coating method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a paper having a paper-forming substrate (hereinafter referred to as "base paper") on one side on which an image forming layer is provided. For a resin-coated paper-type image material coated with a resin layer (A) containing a certain resin (a) and a paper substrate on the opposite side covered with a resin layer (B) containing a resin (b) capable of forming a film. The present invention relates to a support and an image material having the support. More specifically, the running property of the support or the image material during the production of the image material and the winding property of the image material are good, and the cutting precision and the cutting property are good. The present invention relates to a resin-coated paper-type image material support from which an image material and a print thereof can be obtained, and further has excellent running properties and winding properties, and cutting accuracy and cutting of the image material and the print thereof. Material with good properties It is about.

[0002]

2. Description of the Related Art Generally, an image material is composed of 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-sensitive heat-sensitive recording material, and the like are each provided with a silver halide photographic emulsion layer, an ink image-receiving layer, Image forming layers such as a heat transfer type thermal transfer recording image receiving layer, a thermosensitive coloring layer, and a photosensitive thermosensitive coloring layer, and, if necessary, an auxiliary functional layer such as an undercoat layer, a protective layer, and a backing layer. hand,
(Hereinafter, may be simply referred to as an image forming layer). In particular, silver halide photographic constituent layers include a silver halide photographic emulsion layer, a protective layer, an undercoat layer, an intermediate layer or an anti-color mixing layer, an antihalation layer, or a filter layer, an ultraviolet absorbing layer, a back layer, and the like. It is composed of those combinations. For example, a single silver halide photographic material has a silver halide photographic emulsion layer and a protective layer provided on a photographic material support. Also,
The multi-layer silver halide color photographic material comprises an undercoat layer, a blue-sensitive silver halide photographic emulsion layer and an intermediate layer, a green-sensitive silver halide photographic emulsion layer and an ultraviolet absorbing layer, and a red-sensitive silver halide on a photographic material support. A silver halide color photographic constituting layer such as a photographic emulsion layer and a protective layer is provided in order and arranged in a multilayer structure.

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 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, a support for photographic materials in which both sides of a base paper were coated with a polyethylene resin has been mainly used 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-AA.
There has been proposed a thermal transfer recording image receiving element having, as a support, the following resin-coated paper, in particular, a polyethylene resin-coated paper in which the surface of a base paper is coated with a polyethylene resin. 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 both sides of a base paper, particularly a base paper mainly composed of natural pulp, are coated with a resin layer containing a resin capable of forming a film,
It still has some serious problems and has not yet achieved satisfactory results.

First, the side on which the image forming layer of the base paper mainly composed of natural pulp is provided (hereinafter, the side on which the image forming layer is provided is the front side, the resin layer coated on the front side is the front resin layer, and the opposite side is the opposite side). Is coated on the back side, and the resin layer coated on the back side is sometimes referred to as a back resin layer). In producing an image material using the resin-coated paper as a support, there are problems regarding the running property of the image material support or the image material and the winding property of the image material. That is, the resin-coated paper type image material support is unwound from an unwinder, and a coating solution for an image forming layer is formed in a coating and drying process.
In particular, when applying and drying a coating solution for a multilayer silver halide color photographic component layer and winding the image material with a winder,
There has been a problem that the support for the image material or the image material may meander between the steps from the unwinder to the winder through the coating and drying steps, often causing poor running properties and causing serious troubles in the process. In addition, the winding state of the image material in the winder is often not uniform with both ears, or the winding hardness is not uniform, so that the winding property is poor, and the winding, packaging, transporting, cutting, etc. However, there is a problem in that the subsequent steps of the method cause serious trouble.

Further, the running property of the resin-coated image material support or the image material at the time of manufacturing the image material (the term of the resin-coated image material support or the running property of the image material at the time of manufacturing the image material, Hereinafter, it may be simply abbreviated as running property) and the winding property of the image material (the term of the winding property of the image material may be simply abbreviated as the winding property below).
However, there is a problem that the higher the coating speed at which the coating solution for image forming layer is applied to the support, that is, the higher the moving speed of the support, the worse. As a result of investigations by the present inventors on this point, in the slide hopper type or extrusion bar type coating method, the coating speed is 150 m / min or more, further 200 m / min or more, especially the running property and winding speed are 250 m / min or more. It has been found that the takeability is poor. In addition, 250m / min or more, further 300
In the curtain coater system at m / min or more, especially at 350 m / min or more, it was found that the running property and the winding property were significantly deteriorated.

Secondly, an image material having a resin-coated paper as a support and a print after the image forming process, particularly a silver halide photographic material and a print after a developing process, most of the roll-shaped prints, are provided by a guillotine cutter. A cutter, such as a precision print cutter, is used to cut to the desired size.At this time, the image material or its print is not cut accurately, and it is not cut to the desired size. Often, the problem arises that lowers the commercial value. In addition, in the case of remarkable,
In particular, silver halide photographic materials and their prints (prints of silver halide photographic materials, hereinafter sometimes simply referred to as photographic prints) have the problem that they are hardly cut and bent (hereinafter referred to as image in the present specification). When cutting a material or its print, a whisker-like thing is generated from the cut surface, or the phenomenon that it is bent almost without being cut in the first place is sometimes simply referred to as cutability,
In addition, the accuracy of the cut size of an image material or a print thereof is sometimes simply referred to as cutting accuracy).
In particular, the phenomenon that the cutting performance deteriorates is especially when the roll-shaped photo print is cut at high speed with a precision print cutter, and the interval between the blades (hereinafter, sometimes simply referred to as the blade width) is set widely. Sometimes observed. On the other hand, the problem of the cutting accuracy is that if the cutting performance is considerably deteriorated, there is a certain correlation with the cutting performance, but there is no direct correlation with the cutting performance. It was unknown.

Third, an image material in which an image forming layer and an auxiliary functional layer are coated on a resin-coated paper-type support and the strength of the print are the processability of a processing device for producing a print from the image material. From the viewpoint of the appreciation of the finished print and the like, it is preferable that the image material and the print are strong. However, image materials and prints using conventional resin-coated paper as a support tend to be weak,
In some cases, a problem occurs in the processability of the image material and the appreciation of the print. The tendency of the image material and its print to become weaker is greatly affected by the factors of the resin-coated paper serving as a support, and the more the action is taken in the direction to improve the cutability of the resin-coated paper, the more the stiffness of the resin-coated paper becomes. There is a problem in that the image material and its prints are further weakened.

Until now, various proposals have been made to improve the cutting properties of a resin-coated paper-type support. Use of pulp having a specific fiber length and a specific amount of strength agent described in JP-A-55-98748, JP-A-63-173045, JP-A-63-256788, JP-A-63-306442,
Japanese Patent Application Laid-Open No. 3-149542, Japanese Patent Publication No. 48-9963, Japanese Patent Application Laid-Open No. 58-95732, Japanese Patent Application Laid-Open No. 6-230517, No. 6-266046,
Japanese Patent Application Laid-Open No. 7-36147 discloses a technique relating to a back resin layer such as use of a specific polyethylene resin or a resin composition.

[0011] However, although the cutting properties of an image material and a print thereof using a resin-coated paper using the prior art relating to the base paper and the backing resin layer as a support are improved to some extent, the blade of a precision print cutter can be used. If the blade is worn or the blade width is set to a wide value (for example, if the blade width is set to 70 μm or more, particularly 80 μm or more, particularly 90 μm or more), the cutting property is still insufficient.
In addition, it is thought that the cutting properties of an image material using a resin-coated paper as a substrate as a substrate are determined by the factors of the base paper, the resin layer, and the image forming layer being intertwined with each other. It was not clear at the moment.

Further, there is no prior art relating to the cutting accuracy of the image material and its print, and the factor of the cutting accuracy was not clear at all. On the other hand, there is no prior art relating to the running property of the image material support or the image material and the winding property of the image material at the time of manufacturing the image material, and their factors were not completely evident.

[0013]

Accordingly, an object of the present invention is to provide a resin (a) having a film-forming ability on the side of the paper substrate on which the image forming layer is to be provided, using paper mainly composed of natural pulp as a substrate.
And a resin-coated paper type image material support coated on the opposite side with a resin layer (B) containing a film-forming resin (b) and an image having the support An image material having good running properties of a support or an image material during production of the image material and good winding property of the image material, and excellent cutting accuracy and cutting property, and a resin coating capable of obtaining a print thereof. The present invention provides a paper-type image material support, and supports a resin-coated paper having good running and winding properties, and excellent cutting accuracy and cutting properties of the image material and its print. The purpose is to provide a body imaging material. Other objects of the present invention are:
It will be clear from the description in the following specification.

[0014]

The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, the paper on which the image forming layer of the paper substrate is provided with the film on the side of natural pulp as a substrate is used. An image material support coated with a resin layer (A) containing a resin (a) capable of forming a film, and coated on the opposite side with a resin layer (B) containing a resin (b) capable of forming a film; The layer (B) has a roughened surface, and a back layer is coated on the resin layer (B) side, and the cut of the back layer surface is measured by a stylus type three-dimensional surface roughness meter. Center plane average roughness in the papermaking direction at an off value of 0.8 mm (SRa1)
Is 1.35 μm to 2.35 μm, and the average surface roughness (SRa2) in the papermaking direction at a cutoff value of 0.025 mm of the back layer surface measured by a stylus type three-dimensional surface roughness meter.
Was found to achieve the object of the present invention by a support for an image material characterized by having a thickness of 0.20 μm to 0.45 μm.

The center plane average roughness (SR) in the papermaking direction at a cut-off value of 0.8 mm or a cut-off value of 0.025 mm measured using a stylus type three-dimensional surface roughness meter referred to herein.
a) is defined by Equation 1.

[0016]

(Equation 1)

In Equation 1, Wx represents the length of the sample surface area in the X-axis direction (papermaking direction), and Wy is the length of the sample surface area in the Y-axis direction.
(In the direction perpendicular to the papermaking direction), and Sa represents the area of the sample surface area.

More specifically, as a stylus-type three-dimensional surface roughness meter and a three-dimensional roughness analyzer, SEKA manufactured by Kosaka Laboratory Co., Ltd.
-3AK model and SPA-11 model can be used to determine the center plane average roughness (SRa1) at a cutoff value of 0.8 mm and the center plane average roughness (SRa2) at a cutoff value of 0.025 mm. I can do it.

An object of the present invention is to provide a back layer having a center plane average roughness (SRa1) of 1.40 μm to 2.05 μm, especially 1.70 μm.
Significant achievements have been found with a support for the imaging material which is between 45 μm and 1.75 μm. Further, an object of the present invention is that the center plane average roughness (SRa2) of the back layer surface is
0.24 μm to 0.40 μm, especially 0.26 μm to 0.35 μm
It has been found that a remarkable achievement is achieved by a support for an image material.

[0020] Another object of the present invention is to use a hardwood bleached kraft pulp as a natural pulp.
It has been found that it can be effectively achieved. Further, the object of the present invention is to provide, as a natural pulp, a fiber length of pulp defined below in the range of 0.45 mm to 0.65 mm, and further 0.48 m
It has been found that this is achieved significantly by using those in the range from m to 0.62 mm, still more in the range from 0.50 mm to 0.59 mm, in particular in the range from 0.53 mm to 0.59 mm. Pulp fiber length: A 4 cm × 4 cm paper substrate of an image material support is immersed in 80 cm ³ of a 1.0 N aqueous sodium hydroxide solution for 3 days, and then sufficiently washed with water. Then 3% by weight of water
(Pure water) Put a sufficiently washed paper substrate into a dispersing device (a device that does not cut fibers as much as possible, specifically, a juicer mixer with a rounded blade) so that it becomes a slurry, and stir for 20 minutes. Disintegrate to obtain a pulp slurry. About this pulp, JAPAN TAPPI paper pulp test method No. 52-89 This is a value expressed by a length-weighted average fiber length (mm) measured according to "Paper and Pulp Fiber Length Test Method".

Further, the object of the present invention is as described above (paragraph 001).
4, 0019 and 0020), comprising an image forming layer provided on the image material support,
It has been found that it is achieved effectively or significantly.
Further, an object of the present invention is that the coefficient of kinetic friction of the uppermost layer on the image forming side is 0.25 or more, more preferably 0.27 or more, especially 0.29.
The present invention has been found to be remarkably achieved by the image material provided with the image forming layer in the above range, and has reached the present invention.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The support for an image material according to the present invention has a structure in which a resin in a front resin layer and a resin in a back resin layer are formed of a thermoplastic resin, preferably a polyolefin resin, particularly preferably a polyethylene resin on a running base paper. In this case, it is produced by a so-called melt extrusion coating method in which a resin composition for the front resin layer and the back resin layer is cast into a film from a slit die using a melt extruder and coated. Usually, using a melt extruder on a running base paper, the molten resin composition is extruded from the slit die into a film, cast and coated, and pressed between a pressure roll and a cooling roll, It is produced in a series of steps of being separated from the chill roll. At that time, the temperature of the molten film is preferably 270 ° C to 340 ° C. As the slit die, a flat die such as a T-type die, an L-type die, or 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. Also, tables,
The resin layer on the back side is successively, preferably continuously, extrusion-coated, and is preferably coated on the base paper by a so-called tandem extrusion coating method.If necessary, the front or back resin layer may be a multilayer of two or more layers. It may be coated by a multilayer extrusion coating method. The surface resin layer surface of the support for image materials has a glossy surface.
It can be processed to a finely rough surface, matte surface, silk surface, or the like described in Japanese Patent Application Laid-Open No. H10-260,036.

The support for an image material in the present invention is obtained by roughening the back resin layer (B). Usually, the roughening of the back resin layer is carried out by using a resin composition for the back resin layer. When melt-extrusion coating is performed, a roughened cooling roll may be used as the cooling roll. The roughened cooling roll is preferably roughened by a sand blast method and subjected to chrome plating, and can be manufactured and obtained by a cooling roll maker. In making the cooling roll, sand blasting conditions such as sand material, particle shape, particle size, sand physical properties such as particle size distribution, blast time, blast speed, roll rotation speed, substrate surface roughness, plating thickness, plating solution The roll manufacturing conditions such as the plating process conditions such as the composition and the processing current are defined by a cut-off value of 0.8 m for the back layer surface after the back layer is applied.
center plane average roughness (SRa1) at m and cutoff value 0.0
A resin-coated paper is manufactured using a cooling roll manufactured under a series of roll manufacturing conditions so that the center plane average roughness at 25 mm (SRa2) is the design target.
Center plane average roughness of the back layer surface of the resin-coated paper (SRa1)
And the center plane average roughness (SRa2) can be determined.

The both sides of the base paper of the image material support in the present invention are covered with a resin layer containing a resin capable of forming a film. Thermoplastic resins such as polyolefin resins, polycarbonate resins, polyester resins, polyamide resins and mixtures thereof are preferred as those film-forming resins. Among them, polyolefin resins and / or polyester resins are further preferred from the viewpoint of melt extrusion coating properties. Preferably, a polyethylene resin is particularly preferable. Further, it may be covered with a resin layer composed of an electron beam curable resin described or exemplified in JP-B-60-17104.

The polyethylene resins for the front and back resin layers preferably used in the practice of the present invention include low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, linear low-density polyethylene resin,
Ethylene and propylene, copolymers of α-olefins such as butylene, ethylene and acrylic acid, ethyl acrylate, copolymers or graft copolymers such as maleic anhydride, so-called carboxy-modified polyethylene resins, Polyethylene resin by high pressure radical polymerization using autoclave type reactor, tubular type reactor, polyethylene resin produced by polymerization using metallocene polymerization catalyst, Ziegler method, Phillips method, etc. It is a polyethylene resin produced by polymerization using a metal catalyst and a mixture thereof, and has various densities and melt flow rates (hereinafter, JIS K 6760).
The melt flow rate defined by the formula (hereinafter simply referred to as MFR), molecular weight and molecular weight distribution can be used. These polyethylene resins usually have a density of 0.8.
^{7g / cm 3 ~0.97g / cm 3} , preferably 0.90g / cm ³ ~0.
97 g / cm ³ range, MFR 0.05 g / 10 min to 500 g / 10
Min, preferably from 0.08 g / 10 min to 300 g / 10 min, more preferably from 0.1 g / 10 min to 200 g / 10 min, even more preferably from 0.2 g / 10 min to 100 g / 10 min, particularly preferably Is 0.
Those having a range of 3 g / 10 min to 40 g / 10 min can be advantageously used alone or in combination.

The polyethylene resin for the back resin layer preferably used in the practice of the present invention has an MFR of 2.5 g / 10
Min to 40 g / 10 min, 90 to 40 parts by weight of high density polyethylene resin having a density of 0.960 g / cm ³ or more and MF
R: 0.2 g / 10 min to 10 g / 10 min, density: 0.935 g / cm ³
A compound resin composition obtained by previously melting and mixing 10 parts by weight to 60 parts by weight of the following low-density polyethylene resin or medium-density polyethylene resin is preferable.

The MFR of the high-density polyethylene resin for the back resin layer preferably used in the practice of the present invention is preferably 2.5 g / 10 min to 40 g / 10 min, more preferably 4 g / 1.
0 minutes to 35 g / 10 minutes, still more preferably 6 g / 10 minutes to 35 g / 1
0 minutes, particularly preferably in the range of 10 g / 10 minutes to 30 g / 10 minutes. If the MFR of the resin is too low, the cuttability, the adhesiveness between the base paper and the resin layer, the high-speed processability, and the like tend to be insufficient. Workability and the like tend to be insufficient. Further, the density of the high-density polyethylene resin is preferably 0.960 g / cm ³ or more. .962 g / cm ³ or more.

The MFR of the low-density polyethylene resin or the medium-density polyethylene resin for the back resin layer preferably used in the practice of the present invention is preferably 0.2 g / 10 g.
Min to 10 g / 10 min, but if the MFR is too low,
The mixing properties of the resin, the adhesion between the base paper and the resin layer, the high-speed processability, and the like tend to be insufficient. If the MFR is too high, the moldability and the curl properties tend to be insufficient. More preferably, 0.2 g / 10 min to 6 g / 10 min, still more preferably 0.2 g / 10 min to 4.0 g / 10 min, particularly preferably 0.2 g / 1.
The range is from 0 minutes to 2 g / 10 minutes. Also, as the density of low-density polyethylene resin or medium-density polyethylene resin,
It is preferably 0.935 g / cm ³ or less, and if the density is too high, the moldability of the resin composition and the adhesiveness between the base paper and the resin layer tend to be insufficient, and preferably 0.930 g / cm ^3. c
m ³ or less.

The amount of the high-density polyethylene resin used in the compound resin composition comprising a high-density polyethylene resin and a low-density or medium-density polyethylene resin preferably used in the practice of the present invention is 90 parts by weight to 40 parts by weight. The range is preferably, more preferably 90 parts by weight to 50 parts by weight.
Parts by weight, even more preferably from 85 to 60 parts by weight, particularly preferably from 85 to 70 parts by weight. If the amount of the high-density polyethylene resin is too small, the curl physical properties and stiffness of the image material tend to be insufficient, and if the amount is too large, the cutting property of the image material, the mixing property of the resin, the molding process Properties, adhesion between the base paper and the resin layer, and the like tend to be insufficient.

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. If the polyethylene resin is not used as a compound resin, but directly added to the melt extruder in the state of simple mixing and melt extrusion coated, the adhesion between the base paper and the resin layer, the mixing properties of the resin, the molding process Properties tend to be insufficient.

The resin layer on the front side or the back side of the image material support in the present invention may have a two-layer structure, a three-layer structure or a multilayer structure of more layers. The support for an image material in the present invention is manufactured by a so-called melt extrusion coating method in which a resin composition melted by heating and casting is coated on a normally running base paper.
A so-called co-extrusion coating method in which multiple resin layers of three or more layers are simultaneously extruded and coated may be used. A so-called sequential extrusion coating method in which melt extrusion coating is performed sequentially at separate stations in sequence may be used. For example, at least two resin layers,
In the case of three or more layers, at least the lowermost resin layer is melt-extruded and coated, and then the intermediate layer and the uppermost resin layer are formed on the resin layer by using another two-layer co-extruder. A sequential extrusion coating method in which two resin layers are simultaneously extruded and then sequentially coated with a resin layer can be used. Further, at the time of sequential extrusion coating, at least the lowermost resin layer may be subjected to activation treatment such as corona discharge treatment,
It does not have to be applied.

The type of the multilayer co-extrusion die may be any type such as a feed block type, a multi-manifold type and a multi-slot type.
Further, the temperature of the molten film is preferably 270 ° C. to 340 ° C., and in that case, the temperature difference between the resin composition for the uppermost layer and the resin composition constituting the lower resin layer may be provided. . For example, the temperature of the resin composition for the uppermost layer is set to be 5 degrees lower than the temperature of the resin composition constituting the lower resin layer.
By lowering by about 20 ° C., the releasability of the resin layer from the cooling roll can be improved.

The thickness of the resin layers on the front and back of the image material support in the present invention is not particularly limited, but the thickness of the front resin layer is useful in the range of 8 μm to 100 μm. , Preferably in the range of 12 μm to 60 μm, 18 μm
Particularly preferred is a range of ４０40 μm. As the thickness of the back resin layer, it is preferable to appropriately set the thickness of the surface resin layer, particularly in a range for obtaining a curl balance, and generally a range of 5 μm to 100 μm is useful.
Particularly preferred is a range of 12 μm to 40 μm. In addition, it is preferable that the difference in the amount of resin coating on the front and back surfaces is 3 g / m ² or more by reducing the amount of coating on the back resin layer as compared with the surface 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, JP-B1-138
No. 91, Japanese Patent Publication No. 38292/1989, or titanium oxide, zinc oxide, talc or the like described or exemplified in each gazette such as JP-A-1-105245
White pigments such as calcium carbonate, fatty acid amides such as stearamide and arachidic amide, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, and fatty acid metal salts such as calcium palmitate Hindered phenols described in or described in JP-A-1-105245, hindered amine, phosphorus-based, various antioxidants such as sulfur-based, 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 Japanese Patent No. 254440 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 in the compound resin composition for the back resin layer used in the practice of the present invention, a high-density polyethylene resin and a low-density polyethylene resin or a medium-density polyethylene resin, Alternatively, it may be added at the time of preparing the compound resin, or a masterbatch added at a high concentration to the resin may be prepared in advance, and the masterbatch may be added to the resin at the time of melt extrusion coating.

The surface resin layer surface of the support for an image material according to the present invention is subjected to an activation treatment such as a corona discharge treatment or a flame treatment.
An undercoat layer described or exemplified in JP-A-1-102551, JP-A-1-66035 and the like can be applied.

The support for an image material according to the present invention is preferably prepared by subjecting a backing resin layer side thereof to a suitable activation treatment such as a corona discharge treatment or a flame treatment, and then applying various backing layers to prevent static charge. Is applied. In the back layer, inorganic antistatic agents such as colloidal silica, colloidal alumina, hectorite clay colloids and mixtures thereof described or exemplified in JP-A-5-107688, binders, organic antistatic agents or binders and electrifications A water-soluble synthetic polymer compound having a carboxyl group or a sulfone group or a salt thereof or a hydrophilic synthetic polymer colloid substance or a salt thereof described in or exemplified in JP-A-59-214849 for both purposes of prevention, Showa 59-214849
Or latex described in JP-A-58-14131, and starch described or exemplified in JP-A-58-14131.
JP-45248-A or exemplified polyvinyl pyrrolidone, JP-A-62-220950 described or exemplified polyvinyl alcohol, JP-A 63-189859 described or exemplified chitosan and other polymers, Hardening agents described or exemplified in JP-A-56859, matting agents described in JP-A-59-21849 or exemplified, surfactants and the like can be appropriately combined.

As an apparatus for applying the coating liquid for the back layer, an air knife coater, a roll coater, a bar coater, a blade coater, a slide hopper coater,
A gravure coater, a flexographic gravure coater, a combination thereof and the like can be mentioned. In addition, examples of the drying device for the applied coating liquid include various types such as a linear tunnel dryer, an arch dryer, an air loop dryer, a hot air dryer such as a sine curve air float dryer, an infrared heating dryer, and a microwave dryer. A drying device can be mentioned.

As the natural pulp used in the practice of the present invention, the fiber length of the pulp defined in the present specification is 0 in view of the effect of improving the cutting properties, cutting precision and stiffness of the image material and its print. It is preferably in the range of 0.45 mm to 0.65 mm, more preferably in the range of 0.48 mm to 0.62 mm, still more preferably in the range of 0.50 mm to 0.59 mm, and more preferably in the range of 0.53 mm Those having a range of 0.55 mm are particularly preferred. To adjust natural pulp having a fiber length in the above range, specifically, select an appropriate pulp type and use a beating machine having an appropriate structure to beat the beating time, pulp concentration, beating power, etc. The conditions can be adjusted by beating under a series of combined experimental conditions and measuring the fiber length of the pulp of the collected pulp slurry. In addition, pulp beating conditions include:
It is preferable to optimize the balance between the cutting beat and the viscous beat, and the freeness of the pulp after the beat is from 200 ml to 40 ml.
A range of 0 ml is preferred, a range of 230 ml to 370 ml is more preferred, and a range of 260 ml to 340 ml is particularly preferred.

The base paper used in the practice of the present invention is preferably a natural pulp paper whose main component is ordinary natural pulp. Further, a mixed paper made of natural pulp as a main component and synthetic pulp and synthetic fiber may be used. Such natural pulp is described or exemplified in JP-A-58-37642, JP-A-60-67940, JP-A-60-69649, JP-A-61-35442 and the like. It is advantageous to use such appropriately selected natural pulp. Natural pulp was subjected to normal bleaching treatment of chlorine, hypochlorite, 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 of softwood pulp, hardwood pulp, softwood mixed pulp is advantageously used,
In addition, various types such as kraft pulp, sulfite pulp, and soda pulp can be used, and hardwood bleached kraft is particularly advantageously used.

Various additives can be incorporated into the base paper mainly composed of natural pulp used in the practice of the present invention when preparing 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., as a filler, clay, , Kaolin, calcium carbonate, titanium oxide, etc., as a fixing agent, aluminum chloride, water-soluble aluminum salts such as bansulfate, etc., as a pH regulator, caustic soda, sodium carbonate, sulfuric acid, etc., and JP-A-63-204251. Described in JP-A 1-266537 Exemplary coloring pigments, coloring dyes, that allowed to contain appropriately combining a fluorescent whitening agent is advantageous.

A composition comprising various water-soluble polymers or hydrophilic colloids or latexes, an antistatic agent, and additives in or on a base paper mainly composed of natural pulp used in the practice of the present invention. Can be contained or applied by a size press, a tab size press, a blade coating, an air knife coating or the like. As a water-soluble polymer or a hydrophilic colloid, starch-based polymers described or exemplified in JP-A-1-266537, polyvinyl alcohol-based polymers,
Gelatin-based polymer, polyacrylamide-based polymer,
Cellulose-based polymers, etc., emulsions, as latex, petroleum resin emulsions, JP-A-55-4027, and ethylene and acrylic acid (or methacrylic acid) described or exemplified in JP-A-1-80538 are at least constituent elements Emulsion or latex of a copolymer, styrene-butadiene, styrene-acrylic,
Vinyl acetate-acrylic, ethylene-vinyl acetate-based, butadiene-methyl methacrylate-based copolymers and emulsions or latexes of carboxy-modified copolymers thereof, 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 It is advantageous to incorporate pH adjusters such as titanium oxide and titanium oxide, hydrochloric acid, phosphoric acid, citric acid, caustic soda, and other additives such as the above-mentioned coloring pigments, coloring dyes, and fluorescent brightening agents as appropriate.

The thickness of the base paper used in the practice of the present invention is not particularly limited, but the basis weight is 30 μm to 25 μm.
The thickness is preferably 0 μm, but the thickness of the base paper for a support for photo printing is more preferably 70 μm to 220 μm, and particularly preferably 150 μm to 200 μm.

The base paper mainly composed of natural pulp used in the practice of the present invention is preferably a stylus type three-dimensional surface roughness meter on the front side of the base paper from the viewpoint of the smoothness of the image material and its print. The average roughness of the center plane in the papermaking direction at a cutoff value of 0.8 mm measured using the above method is preferably 1.5 μm or less, more preferably 1.4 μm or less, and 1.3 μm or less.
The following are particularly preferred.

For the base paper having a center plane average roughness of 1.5 μm or less, specifically, by using the following method, preferably two or more of the following methods are combined, and more preferably three or more are combined. It is obtained by using.

(1) As the natural pulp to be used, hardwood bleached kraft pulp or a combination of hardwood bleached kraft pulp and hardwood bleached sulphite pulp is preferable. In addition, natural pulp appropriately beaten to have an optimum fiber length and freeness as described in (paragraph 0038) is used.

(2) A tension press is used during the drying of the wet paper. Specifically, for example, a multi-stage tension press described or exemplified in JP-A-3-29945 is performed on the wet paper.

(3) On the side of the base paper on which the image forming layer is to be provided, a coating layer comprising a coating composition containing a binder, preferably various water-soluble polymers, hydrophilic colloids or polymer latexes, is applied. Specifically, a size press or tab size press or blade coating of a coating composition containing various water-soluble polymers, hydrophilic colloids or polymer latex on a base paper on which the image forming layer is provided,
By coating such as air knife coating, the solid coating amount on the side on which the image forming layer is provided is 2 g / m ² or more, preferably 5 g / m ² or more.
It is preferable to apply m ² or more. The coating layer preferably contains various inorganic or organic pigments from the viewpoint of further improving the smoothness.

(4) After the base paper is formed, at least two sheets are formed using a machine calender, a super calender, a heat calender, or the like.
Perform calendar processing for the series or higher on the base paper. In particular,
For example, the base paper is subjected to machine calendar processing and / or thermal machine calendar processing as a first series calendar processing, and then further calendar processing and heat calendar processing as second and subsequent calendar processing, which are described in JP-A-4-110939. Alternatively, it is preferable to carry out a thermal soft calender treatment as exemplified or a combination treatment thereof. Further, it is preferable that the calendering of the second and subsequent series is also performed on-machine after the base paper is made.

The image material of the present invention is obtained by coating an image forming layer comprising various image forming layers and, if necessary, an auxiliary functional layer on the image material support of the present invention. Specific examples of the image material in the present invention include, for example, a silver halide photographic material, an ink jet recording material,
Thermal transfer type thermal transfer recording image-receiving materials, heat-sensitive recording materials, light- and heat-sensitive recording materials, and the like can be given. These may be formed on a support for an image material according to the present invention, respectively. It is provided with auxiliary functional layers such as an undercoat layer, a protective layer, and a back layer. In particular, silver halide photographic materials include a silver halide photographic emulsion layer, a protective layer, an undercoat layer, an intermediate layer or an anti-color mixing layer, an antihalation layer, or a filter layer.
A silver halide photographic component layer comprising an ultraviolet absorbing layer, a back layer and the like and a combination thereof is provided on a photographic material support. For example, a single silver halide photographic material has a silver halide photographic emulsion layer and a protective layer provided on a photographic material support. Further, the multilayer silver halide color photographic material is provided with an undercoat layer on a photographic material support,
Multi-layer silver halide color photographic layers such as a blue-sensitive silver halide photographic emulsion layer and an intermediate layer, a green-sensitive silver halide photographic emulsion layer and an ultraviolet absorbing layer, a red-sensitive silver halide photographic emulsion layer and a protective layer are sequentially coated. In a multilayer arrangement.

From the viewpoint of further improving the winding property, the image material of the present invention is preferably provided with an image forming layer having a dynamic friction coefficient of 0.25 or more on the uppermost layer on the image forming side. Those having an image forming layer in a range of 0.27 or more are more preferable, and those having an image forming layer in a range of 0.29 or more are particularly preferable. In addition, the dynamic friction coefficient referred to in this specification is JIS P8147-1987.
According to the standard, a ferro-type plate was fixed on a horizontal plate, the test piece was attached only to the weight, and the moving speed of the lower movable beam was measured at 500 mm / min. Say the coefficient. In order to make the dynamic friction coefficient of the uppermost layer of the image material of the present invention 0.25 or more, specifically, the center surface average roughness at a cutoff value of 0.8 mm of the surface resin layer is preferably 0.17 μm or less. Is 0.15 μm or less, more preferably 0.13 μm or less, particularly preferably 0.11 μm or less. [To manufacture such an image material support, use the method described in (paragraph 004)
3) It is particularly useful to use a base paper having good smoothness as described above, to increase the thickness of the surface resin layer, etc.], and to formulate a coating liquid for an image forming layer so that unevenness on the uppermost layer surface is minimized. (Limit the amount of matting agent used, use gelatin with high jelly strength, etc.), apply, set, and dry the coating solution for the image forming layer uniformly and smoothly. For example, a method of using a coating solution for the uppermost layer that increases the composition (such as selection of an appropriate coating aid) may be used.

The image material according to the present invention includes color photographic paper, black-and-white photographic paper, typesetting photographic paper, copy photographic paper, reverse photographic material, and various photographic constituent layers.
Includes those for various uses such as silver salt diffusion transfer method for negative, positive, and printing materials. For example, those provided with silver chloride, silver bromide, silver chlorobromide, silver iodobromide, and silver chloroiodobromide emulsion layers are included. It includes a silver halide photographic emulsion layer containing a color coupler and a multilayer silver halide color photographic constituting layer. In addition, those having a photographic component layer for silver salt diffusion transfer method are also included. As binders for those photographic constituent layers, other than ordinary gelatin, polyvinylpyrrolidone,
A hydrophilic polymer substance such as polyvinyl alcohol and a polysaccharide sulfate compound can be used. Further, the above-mentioned photographic constituent layer can contain various additives. For example, as sensitizing dyes, cyanine dyes, merocyanine dyes, etc., as chemical sensitizers, water-soluble gold compounds, sulfur compounds, etc., as antifoggants or stabilizers, hydroxy-triazolopyrimidine compounds, mercapto-heterocyclic compounds, etc. , Formalin as a hardening agent,
Vinyl sulphone compounds, aziridine compounds, etc., as coating aids, alkylbenzene sulphonates, sulfosuccinic acid ester salts, etc., as pollution inhibitors, dialkyl hydroquinone compounds, etc., as well as fluorescent brighteners, sharpness improving dyes, antistatic agents, pH Preparations, fogging agents,
In addition, water-soluble iridium during the formation and dispersion of silver halide,
A water-soluble rhodium compound or the like can be appropriately combined and contained.

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

The image material in the present invention includes various types of thermal transfer recording image-receiving materials coated with various types of thermal transfer recording image-receiving layers. As the synthetic resin used for the thermal transfer recording image receiving layer, polyester resin, polyacrylate resin, polycarbonate resin, polyvinyl acetate resin,
Polyvinyl butyral resin, styrene acrylate resin, resin having ester bond such as vinyl toluene acrylate resin, resin having urethane bond such as polyurethane resin, resin having amide bond such as polyamide resin, resin having urea bond such as urea resin, Other examples include a polycaprolactam resin, a styrene resin, a polyvinyl chloride resin, a vinyl chloride-vinyl acetate copolymer resin, and a polyacrylonitrile resin. In addition to these resins,
Mixtures or copolymers of these can also be used.

Further, in the thermal transfer recording image receiving layer, a releasing 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, and Teflon 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. Examples of the curable silicone oil include a reaction curable type, a photocurable type, and a catalyst curable type, and a reaction curable 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 preferably from 0.1% by weight to 20% by weight in the image receiving layer. As the pigment, silica, calcium carbonate, titanium oxide,
Extenders such as zinc oxide are preferred. The thickness of the image receiving layer is preferably 0.5 μm to 20 μm, and more preferably 2 μm to 10 μm.
μm is more preferred.

The image material in the present invention includes various ink jet recording materials provided with 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. , Normal 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 , Polyvinylpyrrolidone, polyvinylpyridium 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 their salts, synthetic polymers such as polyethylene imine, styrene
Conjugated diene copolymer latex such as butadiene copolymer, methyl methacrylate / butadiene copolymer, polyvinyl acetate, vinyl acetate / maleic ester copolymer, vinyl acetate / acrylate copolymer, ethylene / vinyl acetate Acrylic polymers or copolymers such as vinyl acetate polymer latex such as copolymer, acrylate polymer, methacrylate polymer, ethylene / acrylate copolymer, styrene / acrylate copolymer, etc. Thermoset synthetic resin such as a latex of coalesced polymer, vinylidene chloride copolymer latex, or a functional group modified polymer latex by a monomer containing a functional group such as a carboxyl group of these various polymers, melamine resin, urea resin, etc. Water-based adhesives such as polymethyl methacrylate, polyurethane resin, Polyester resins, vinyl chloride-
Synthetic resin adhesives such as vinyl acetate copolymer, polyvinyl butyral, and alkyd resin, Japanese Patent Publication No. 3-24906,
JP-A-3-281383, and inorganic binders such as alumina sols and silica sols described or exemplified in each gazette such as Japanese Patent Application No. 4-240725 can be used alone or in combination. it can.

The ink receiving layer 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; fluorinated surfactants described in JP-B-47-9303, U.S. Pat. Ethoxysilane, N-β (aminoethyl) γ
Silane coupling agents such as aminopropyltrimethoxysilane; hardening agents for polymers; hardening agents such as active halogen compounds, vinylsulfone compounds, aziridine compounds, epoxy compounds, acryloyl compounds, and isocyanate compounds; P-hydroxybenzoic acid ester compounds described or exemplified in Kaihei 1-102551, benzisothiazolone compounds, isothiazolone compounds, etc., JP-A-63-204251, JP-A 1-266537, etc. Sodium hydroxymethanesulfonate and sodium P-toluenesulfonate as yellowing inhibitors such as coloring pigments, coloring dyes and fluorescent whitening agents; benzotriazole having a hydroxy-di-alkylphenyl group at the 2-position as an ultraviolet absorber As an antioxidant such as a compound, JP-A-1-105245 Such as described or illustrated in the poly hindered phenol compounds in Japanese, as pencil Categories include starch particles, barium sulfate fine particles of organic or inorganic particle diameter 0.2μm~5μm such as silicon dioxide, KOKOKU 4-1
No. 337 publication or the like organopolysiloxane compounds, as a pH regulator, various additives such as caustic soda, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, octyl alcohol, silicon-based antifoaming agent They can be incorporated in appropriate combinations.

[0057]

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.

Examples 1 to 5 and Comparative Examples 1 to 4 After hardwood bleached kraft pulp was beaten so that the fiber length of the pulp specified in this specification was 0.56 mm, pulp 1
3 parts by weight of cationized starch, 0.2 parts by weight of anionized polyacrylamide, 0.4 parts by weight of alkyl ketene dimer emulsion (as ketene dimer), 0.4 parts by weight of polyamide epichlorohydrin resin,
A stock slurry was prepared by adding 1.5 parts by weight of amphoteric polyacrylamide (molecular weight: 1,000,000) and appropriate amounts of an optical brightener, a blue dye and a red dye. Then, the stock slurry was
Place on a fourdrinier paper machine running at 00m / min to give a proper turbulence to form a web,
After performing a three-stage wet press in which the linear pressure was adjusted in the range of 5 to 100 kgf / cm, treated with a smoothing roll,
In the subsequent drying part, two-stage pressing was performed in which the linear pressure was adjusted in the range of 30 to 70 kgf / cm, and then drying was performed. Thereafter, during the drying, 4 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent whitening agent, and 0.0 parts of a blue dye were used.
A size press solution consisting of 02 parts by weight, 4 parts by weight of sodium chloride and 92 parts by weight of water is subjected to a size press of 25 g / m ² and dried so that the finally obtained base paper has a moisture content of 8% by weight on a dry basis. And machine calendered at a linear pressure of 70 kgf / cm to have a basis weight of 170 g / m ² and a density of 1.02 g / cm ³ ,
A base paper for an image material support having a center plane average roughness in the papermaking direction at a cutoff value of 0.8 mm of 1.32 μm was produced.

Next, after the base paper surface (back surface) opposite to the side on which the image forming layer is coated is subjected to corona discharge treatment, a low-density polyethylene resin [density 0.924 g / cm ³ , MFR = 1 g]
/ 10 min] 30 parts by weight and high density polyethylene resin (density 0.9
(67 g / cm ³ , MFR = 15 g / 10 min) A compound resin composition consisting of 70 parts by weight was melt-extruded at a resin temperature of 320 ° C. and a resin thickness of 25 μm at a running speed of the base paper of 200 m / min using a melt extrusion coating machine. , Linear pressure of cooling roll and press roll 40
The melt extrusion coating was performed at kgf / cm. At this time, as the cooling roll, the following roughened cooling roll (CR
-1), cooling roll (CR-2), cooling roll (CR-
3) Using a cooling roll (CR-4), a cooling roll (CR-5) or a cooling roll (CR-6), operation was performed at a cooling water temperature of 12 ° C.

Cooling roll (CR-1), cooling roll (CR
-2), cooling roll (CR-3), cooling roll (CR-
4), cooling roll (CR-5) and cooling roll (CR-6)
Is manufactured by a cooling roll maker, has been roughened by a sand blast method, and has been subjected to chrome plating. In making the cooling roll, sand blasting conditions such as sand material, particle shape, particle size, sand physical properties such as particle size distribution, blast time, blast speed, roll rotation speed, substrate surface roughness, plating thickness, plating solution The roll manufacturing conditions such as the plating process conditions such as the composition and the processing current are combined with the back layer described in Table 1, and the average of the center surface of the back layer surface at a cut-off value of 0.8 mm as defined in the present specification. Roughness (SRa1) and cut-off value 0.02
Using a cooling roll manufactured under a series of roll manufacturing conditions so that the center plane average roughness (SRa2) at 5 mm is as shown in Table 1, the resin-coated paper was further processed through the steps described below. The center plane average roughness (SRa1) and the center plane average roughness (SRa2) of the back layer surface of the manufactured resin-coated paper
Was determined.

Subsequently, the base paper surface (surface) on the side where the silver halide photographic emulsion layer is provided is subjected to corona discharge treatment, and then the following composition (BL-1) is applied to the surface at a resin temperature of 315 ° C. for 30 minutes.
At a running speed of 200 m / min for the base paper to a thickness of μm, the linear pressure of the cooling roll and the press roll was 4 using a melt extrusion coating machine.
Melt extrusion coating was performed at 0 kgf / cm. At this time, a chromium-plated fine rough surface was used as the cooling roll, and the cooling roll was operated at a cooling water temperature of 12 ° C. The melt extrusion coating of the front and back resin compositions was performed by a so-called tandem method in which extrusion coating was performed sequentially. The average roughness of the center plane in the papermaking direction at a cutoff value of 0.8 mm of the surface resin layer surface was 0.130 μm.

Blended composition (BL-1): pellets 17 of the following masterbatch (MB-1W) containing titanium dioxide pigment
8 parts by weight of the following masterbatch (MB-1B) containing titanium dioxide pigment and ultramarine blue and 75 parts by weight of the following pellets of polyethylene resin (R-1) are simply mixed.
(Dry blended) composition.

Masterbatch (MB-1W): Number of titanium dioxide particles surface-treated with hydrous aluminum hydroxide (0.5% by weight as Al ₂ O ₃ per titanium dioxide), pulverized with a steam mill, and measured with an electron microscope 50 weight of anatase type titanium dioxide pigment having an average diameter of 0.120 μm
%, The following polyethylene resin (R-2) 47.5% by weight and zinc stearate 2.5% by weight
In the presence of 0 ppm of 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethyl-benzyl) cyanurate, knead well at 150 ° C. using a Banbury mixer, cool and pelletize. Masterbatch manufactured by

Masterbatch (MB-1B): 50% by weight of the above titanium dioxide pigment, polyethylene resin (R-2) shown below
46.25% by weight, Gunze (Daiichi Kasei Kogyo Co., Ltd., # 2
000) 1.25% by weight and zinc containing stearin 2.5%
%, In the presence of 240 ppm of the above antioxidant, well kneaded at 150 ° C. using a Banbury mixer, cooled and pelletized to produce a master batch.

Polyethylene resin (R-1): density 0.9
A high-pressure low-density polyethylene resin obtained by an autoclave method and having 23 g / cm ³ and an MFR of 4.0 g / 10 minutes.

Polyethylene resin (R-2): 0.92 density
A tubular high-pressure low-density polyethylene resin having a grease of 0 g / cm ³ and an MFR of 8.5 g / 10 min.

Further, after the front and back resin layers are processed and wound up, the back resin layer surface of the resin-coated paper is subjected to a corona discharge treatment.
The following coating solution for back layer (BC-1) was used in combination with the combination shown in Table 1 as a dry weight of 0.1 g / m ² , 0.3 g / m ² ,
On-machine coating was performed at a coating amount of 0.6 g / m ² or 0.9 g / m ² .

Coating solution for back layer (BC-1); styrene: 2
Ethylhexyl acrylate: methacrylic acid: acrylamide = 57: 39: 2.5: 1.5 (% by weight) 2 g of 50% by weight aqueous dispersion of polymer latex and 20% by weight of colloidal silica (Nissan Chemical Co., Ltd.) 30 g of styrene-maleic anhydride copolymer (trade name KS-157, manufactured by Arakawa Chemical Co., Ltd.)
0, a molecular weight of about 70,000, 25 wt% aqueous solution of PH 7.3), a 9 wt% dispersion prepared by emulsifying and dispersing aluminum hydroxide microcrystals having an average particle diameter of 1 μm and an oil absorption of 35 cc / 100 g in water. 3.2 g and 2% of a 10% methanol solution of an epoxy hardener (manufactured by Nagase & Co., Ltd., trade name: NER-010)
-5% by weight of ethylhexyl sulfosuccinate
0.8 g of a 10% water / methanol mixed solution,
Coating solution prepared to 0 g.

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 weight solution of butyl parahydroxybenzoate in methanol and 0.45 g of a 5% by weight mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt. The undercoating solution prepared to 100 g was coated with gelatin at an amount of 0.1 g.
On-machine coating was carried out uniformly to obtain a support for image material of 0.6 g / m ² .

Next, the surface potential of the undercoat layer surface is increased by plus or minus 0.4.
These substrates were charged by a wire charging method so as to have a voltage of 3 kV. Further, in an on-machine system, a blue-sensitive emulsion layer containing the following yellow color coupler, an intermediate layer containing a color-mixing inhibitor, and a green color containing a magenta color coupler adjacent to the undercoat layer of the image material support in the following order: Each of the coating solutions for the emulsion-sensitive layer, the ultraviolet-absorbing layer containing an ultraviolet absorber, the red-sensitive emulsion layer containing a cyan coloring coupler, and the protective layer (the uppermost layer in this specification) was coated at a coating speed of 200 m / min. A color photographic paper having a total amount of gelatin of 8 g / m ² was prepared by simultaneously coating six layers from the bar. As a hardening agent, 2,4-dichloro-6-hydroxy-s-triazine sodium salt (added as an aqueous solution) was used, and 1.6 parts with respect to the total amount of gelatin.
The silver halide color photographic paper was appropriately distributed and contained in each layer so as to be 5% by weight in consideration of the photographic characteristics, storability and the like of the silver halide color photographic paper. The color photographic paper is 4800 with a winder.
m length. The static friction coefficient of the uppermost layer on the image forming side of the color photographic paper was 0.272.

The blue-sensitive emulsion layer has an average grain size of 0.8 μm having a halogen composition of AgBr / AgCl = 95/5 produced by the first thermoforming in the presence of an appropriate amount of potassium hexachloroiridate (III). Sulfur sensitized to sensitivity [1,
A neutral silver halide emulsion composed of a mixed crystal of (0,0) plane and [1,1,1] plane containing 0.6 g / m ² of silver nitrate, 1.5 g / m ^{2 of} gelatin and a yellow color coupler And an appropriate amount of a stabilizer, a sensitizing dye for blue sensation, a coating aid, a hardener, a thickener and the like. The intermediate layer contains, in addition to 1.4 g / m ² of gelatin, an appropriate amount of an anti-color mixing agent, a coating aid, a thickener, a hardener, and the like. The viscosities of the coating solutions for the blue-sensitive emulsion layer and the intermediate layer were 5.5 c each.
Adjusted to p and 100cp, the wet coating amount is 35g each
/ m ² and 7 g / m ² .

The green-sensitive emulsion layer was formed by a first heat-forming in the presence of an appropriate amount of potassium hexachlororhodate (III) and potassium hexachloroiridate (III).
Substantially sulfur-sensitized to an optimum sensitivity of an average particle diameter of 0.4 μm having a halogen composition of gCl = 95/5 [1, 0,
0] plane, containing 0.6 g / m ² of silver nitrate in terms of silver nitrate, gelatin 1.2 g / m ² and a magenta color coupler, an appropriate amount of stabilizer, green sensitizing dye, Contains sharpness improving pigments, coating aids, hardeners, thickeners and the like. The ultraviolet ray absorbing layer contains an appropriate amount of an ultraviolet ray absorbing agent, a coating aid, a thickener, a hardener and the like in addition to 1.3 g / m ² of gelatin. The viscosity of the coating liquid for green-sensitive emulsion layer and the ultraviolet absorbing layer is adjusted to each 50cp and 60 cp, wet coating amount was Coating with 18 g / m ² and 7 g / m ^2, respectively.

The red-sensitive emulsion layer contains a silver halide emulsion prepared in exactly the same manner as the green-sensitive silver halide emulsion, containing 0.6 g / m ² of silver nitrate, 1.1 g / m ^{2 of} gelatin and a cyan color coupler. And an appropriate amount of a stabilizer, a sensitizing dye for redness, a sharpness improving dye, a coating aid, a hardener, a thickener, and the like. Protective layer
(The uppermost layer in this specification) contains 1.5 g / m ² of gelatin, as well as appropriate amounts of coating aids, thickeners, hardeners and the like. The viscosities of the coating solutions for the red-sensitive emulsion layer and the protective layer (the uppermost layer in this specification) are as follows:
Are respectively adjusted to 30cp and 70 cp, wet coating amount was Coating with 15 g / m ² and 10 g / m ^2, respectively.

The following methods were used to evaluate the support for the image material or the running property of the color photographic paper and the winding property of the color photographic paper when the color photographic paper was manufactured as described above. .

The running state of the image material support or the color photographic paper and the winding of the color photographic paper between the steps from the unwinder through the steps of applying and drying the coating solution for the multilayer silver halide color photographic constituent layer to the winder The condition was visually judged by 10 monitors, and a 10-grade evaluation was performed. The evaluation criteria for the running property (the larger the grade value, the better the running property, and the smaller the grade value, the worse the running property) are as follows.

Grades 10 to 9: With respect to running of the support for image material or color photographic paper, there is no or almost no problem such as meandering, and the running property is quite good. Grade 8 to 6: With respect to running of the support for image material or color printing paper, there is little problem such as meandering, but it is generally good, and running properties are good. Grade 5-4: There is a problem such as meandering in running of the support for image material or color photographic paper, but the running property is in a practically usable range. Grades 3-1: There is a practical problem in running the support for the image material or the color photographic paper.

The evaluation criteria for the winding property (the larger the grade value, the better the winding property, and the smaller the grade value, the worse the winding property) are as follows. . Grades 10 to 9: The rolled-up state of the color photographic paper is good for both ears, the rolled-up hardness is uniform, and the roll-up property is quite good. Grade 8-6: The rolled-up state of the color photographic paper is slightly irregular in both ears, and the winding hardness is also slightly non-uniform.
The winding property is generally good. Grade 5-4: The take-up state of the color photographic paper is somewhat poor, but the take-up property is in a practically usable range. Grade 3-1: The rolled-up state of the color photographic paper is poor because the both ears are not uniform or the rolled-up hardness is not uniform, and there is a practical problem in the rollability.

Next, the prepared color photographic paper was cut into rolls having a width of 8.2 cm, stored at 35 ° C. and normal humidity for 5 days, and then printed with color photographs. After drying, a photographic print was prepared. In addition, a series of processes of exposure, development, and drying were performed by an automatic printer and an automatic developing machine. In addition, the color development processing is as follows: color development (45 seconds) → bleaching / fixing (45 seconds) → stable (1 minute 30 seconds) →
The drying procedure was performed.

As a method of evaluating the cutting accuracy of the image material,
The above 8.2 cm wide roll-shaped color photographic print is cut by a precision print cutter having a blade width of 80 μm so as to have a size of 11.7 cm in the length direction, and the length of the cut sample is measured. evaluated. As the evaluation criteria, grades 10 to 9; cutting dimensions are 0 to less than 0.1 mm, and cutting precision is extremely good. Grades 8 to 7; cutting dimensions are less than 0.1 to 0.2 mm, and cutting precision is Good, grade 6-5; cutting dimension is less than 0.2-0.5mm,
Grade 4 to 3; the cutting size is 0.5 mm or more, and the cutting accuracy is practically certain, and grade 2 to 1; the cutting accuracy is not cut in the first place and the cutting accuracy cannot be discussed. Represent.

As a method for evaluating the cutting property of the image material, the above-mentioned 8.2 cm wide roll-shaped color photographic print was measured with a precision print cutter having a blade width of 80 μm and a length direction of 11.7 cm. Then, the cut surface was visually judged by 10 monitors and evaluated. Grade 10
~ 9; the cutting rate with a cutter is 100%, and there is almost no beard from the cut surface, and the cutting property is extremely good. Grades 8 to 7; the cutting rate with a cutter is 100%,
There is little generation of whiskers from the cut surface and the cutability is good. Grade 6 to 5; The cutting rate with the cutter is 100%, and there is whiskers from the cut surface, but there is no practical problem. Grade 4 ~ 3; Cutting rate with cutter is 50
100% unless the blade width is reduced by 10 to 15 μm.
% Cutting rate is not a practical problem, or the cutting rate is 100%, but the generation of whiskers from the cut surface is extremely large. The rate is 0% (accordingly, the failure rate is 100%). If the blade width is not reduced by 20 μm or more, the cutting rate does not become 100%, and in that case, many whiskers are generated from the cut surface,
This indicates that there is some practical problem.

Table 1 shows the obtained results.

[0082]

[Table 1]

Note that (Note 1) to (Note 3) in Table 1 are as follows.

(Note 1) Coating amount of back layer: This indicates the coating amount (g / m ² ) as the dry weight of the back layer. (Note 2) Roughness of back layer surface (SRa1): Average roughness of the center surface of the back layer surface of the support for image materials as defined in the present invention.
(SRa1) (μm). (Note 3) Roughness of back layer surface (SRa2): average roughness of the center layer defined in this specification of the back layer surface of the support for image materials.
(SRa2) (μm).

From the results in Table 1, it can be seen that the back surface resin layer having been roughened
(B) A resin-coated paper-type image material support using paper as a substrate, on which a back layer is provided on the (B) side, wherein the back layer surface has a center plane average roughness (SRa1 ) Is 1.
35 μm to 2.35 μm and a center plane average roughness (SRa2) defined in this specification of 0.20 μm to 0.45 μm
The support for an image material (Examples 1 to 5) in the present invention has good running property of the support or the image material during production of the image material and good winding property of the image material, and It can be clearly seen that this is an excellent support for image materials, which has good cutting precision and cutting properties of the material and its print.

Among the supports for image materials in the present invention, those having an average surface roughness (SRa2) of 0.23 μm to 0.40 μm on the back layer surface are preferred from the viewpoint of the effect of improving cutting accuracy. It is well understood that those having a diameter of 0.26 μm to 0.35 μm are particularly preferable.

On the other hand, the center plane average roughness (SR
a1) is larger than 2.35 μm (Comparative Example 1) or 1.3
When less than 5 μm (Comparative Example 3) or when the center plane average roughness (SRa2) of the back layer surface is more than 0.45 μm
(Comparative Example 1 and Comparative Example 2) and when it is smaller than 0.20 μm
The support for an image material other than the present invention in (Comparative Example 4) has poor running properties of the support or the image material at the time of production of the image material and poor winding property of the image material, and the cutting accuracy of the image material and its print is poor. You can see that it is bad and has a problem.

Examples 6 to 12 and Comparative Examples 5 to 6 Instead of the cooling roll (CR-1) used in Example 1, the center layer average roughness (S
A cooling roll (CR-7) manufactured such that Ra1) and center plane average roughness (SRa2) are as shown in Table 2.
Cooling roll (CR-8), Cooling roll (CR-9), Cooling roll (CR-10), Cooling roll (CR-11)
(CR-12), cooling roll (CR-13), cooling roll
(CR-14) or a cooling roll (CR-15) was used in the same manner as in Example 1. The cooling rolls (CR-7) to (CR-15) were manufactured in the same manner as the cooling rolls (CR-1) to (CR-6).

Table 2 shows the obtained results.

[0090]

[Table 2]

Note that (Note 2) to (Note 3) in Table 2 have the same meanings as those in Table 1.

From the results in Table 2, it can be seen that the back surface resin layer having been roughened
(B) A resin-coated paper-type image material support using paper as a substrate, on which a back layer is provided on the (B) side, wherein the back layer surface has a center plane average roughness (SRa1 ) Is 1.
35 μm to 2.35 μm, and the center plane average roughness (SRa2) defined herein is 0.20 μm to 0.45 μm.
μm of the support for the image material of the present invention (Examples 6 to
Example 12) is that the running property of the support or the image material during the production of the image material and the winding property of the image material are good, and the cutting accuracy and the cutting property of the image material and its print are good. It can be clearly seen that this is an excellent support for image materials.

Also, among the supports for image materials in the present invention, from the viewpoint of the effect of improving the running property of the support or the image material and the winding property of the image material during the production of the image material, the center plane average roughness of the back layer surface is improved. (SRa1) is 1.40 μm ~
2.05 μm is preferable, and 1.45 μm to 1.75 μm
It can be clearly understood that the above is particularly preferable.

On the other hand, the center plane average roughness (SR
In the case where a1) is larger than 2.35 μm (Comparative Example 5) or smaller than 1.35 μm (Comparative Example 6), the support for an image material other than the present invention may be a support or an image material at the time of manufacturing the image material. It can be clearly seen that the running property and the winding property of the image material are poor and there is a problem.

Examples 13 to 19 and Comparative Examples 7 to 8 Instead of the cooling roll (CR-1) used in Example 1, the center layer average roughness (S
Ra1) and a center roll average roughness (SRa2) were manufactured so as to be those shown in Table 3, and the cooling roll (CR-1) was manufactured.
6), cooling roll (CR-17), cooling roll (CR-1)
8), chill roll (CR-19), chill roll (CR-2)
0), chill roll (CR-21), chill roll (CR-2
2), chill roll (CR-23) or chill roll (CR-
The procedure was performed in the same manner as in Example 1 except that 24) was used. The cooling roll (CR-16) to the cooling roll (CR
-24) is a cooling roll (CR-1) to a cooling roll (CR-
It was manufactured in the same manner as in 6).

Table 3 shows the obtained results.

[0097]

[Table 3]

Note that (Note 2) to (Note 3) in Table 3 have the same meanings as those in Table 1.

From the results in Table 3, it can be seen from the result that the back resin layer having been roughened is roughened.
(B) A resin-coated paper-type image material support using paper as a substrate, on which a back layer is provided on the (B) side, wherein the back layer surface has a center plane average roughness (SRa1 ) Is 1.
35 μm to 2.35 μm, and the center plane average roughness (SRa2) defined herein is 0.20 μm to 0.45 μm.
μm support of the present invention (Example 13
In Examples 19), the running property of the support or the image material during the production of the image material and the winding property of the image material are good, and the cutting precision and the cutting property of the image material and its print are good. It can be seen that this is an excellent support for image materials.

Further, among the supports for image materials in the present invention, those having a center plane average roughness (SRa2) of 0.23 μm to 0.40 μm on the back layer surface are preferred from the viewpoint of the effect of improving cutting accuracy. , 0.26 μm to 0.35 μm are particularly preferable.

On the other hand, the center plane average roughness (SR
a2) is larger than 0.45 μm (Comparative Example 7) or the center plane average roughness (SRa2) of the back layer surface is 0.20 μm
The support for an image material other than the present invention in the case of being smaller (Comparative Example 8) is poor in the running property of the support or the image material during production of the image material and the winding property of the image material, or the image material and its print. It can be clearly understood that the cutting accuracy of each of them is poor, and each has a problem.

Examples 20 to 27 Except for using the pulp beaten to the fiber length of the pulp specified in Table 4 in this specification in the production of the base paper of Example 1 (paragraph 0058). A base paper was manufactured in the same manner as in Example 1. The operation was performed in the same manner as in Example 1 except that these base papers were used instead of the base paper used in Example 1.

Table 4 shows the obtained results.

[0104]

[Table 4]

Note that (Note 2) to (Note 3) in Table 4 have the same meanings as those in Table 1. (Note 4) is as follows. (Note 4) Pulp fiber length: The pulp fiber length (mm) specified in the present invention.

The evaluation of the stiffness of the image material support was performed as follows. A 13 cm × 18 cm color photographic print made in the same manner as in Example 1 was shaken up and down with the edge of the color photographic print on 10 monitors, and the waist strength based on the feeling of touch was determined. Grade evaluation was performed. The evaluation criteria for the strength of the waist (the higher the grade value, the stronger the waist, and the lower the grade value, the weaker the waist) are as follows.

Grades 10 to 9: Strong waist. Grade 8-7: The waist is slightly strong. Grade 6-4: The waist is slightly weak, but it is practically possible. Grade 3-1: The waist is weak, which is a practical problem.

From the results shown in Table 4, it can be seen that the support for the image material (Examples 20 to 27) of the present invention has good running properties of the support or the image material during production of the image material and good winding property of the image material. It can be clearly seen that this is an excellent support for an image material which has good cutting properties of the image material and its print. Among them, from the viewpoint of improving the cutting accuracy and cutting properties and the stiffness of the photographic print, the fiber length defined in the present specification of the natural pulp constituting the base paper,
It is preferably in the range of 0.45 mm to 0.65 mm,
It is more preferable that the thickness is in the range of 0.48 mm to 0.62 mm, even more preferably in the range of 0.50 mm to 0.59 mm, and particularly preferably in the range of 0.53 mm to 0.59 mm. I understand well.

Examples 28 to 31 In place of the support for the image material and the protective layer (the uppermost layer as referred to in the present specification) of the red-sensitive emulsion layer used in Example 1, the following combinations were used. Support for image material (S1) to (S4)
And the following protective layer of the red-sensitive emulsion layer (the uppermost layer in the present specification) (P1) to (P2) was used. Note that the center plane average roughness (SRa1) of the back layer surface of each sample specified in this specification is 1.
67 μm to 1.69 μm, center plane average roughness (SRa
2) was in the range of 0.312 μm to 0.315 μm.

Support for image material (S1): In Example 1, a base paper having a center plane average roughness in the papermaking direction at a cutoff value of 0.8 mm of 1.65 μm was used, and the surface resin layer was coated. A support for an image material produced in the same manner as in Example 1 except that the thickness is 28 μm.

Support for image material (S2): In Example 1, a base paper having a center plane average roughness in the papermaking direction at a cutoff value of 0.8 mm of 1.42 μm was used, and the surface resin layer was coated. A support for an image material produced in the same manner as in Example 1 except that the thickness is 28 μm.

Support for image material (S3): The base paper has a center plane average roughness in the papermaking direction at a cutoff value of 0.8 mm of 1.32.
μm, and a support for an image material having the coating thickness of the surface resin layer of 30 μm (the same as in Example 1).

Support for image material (S4): A base paper having a cut-off value of 0.8 mm and an average surface roughness of 1.14 μm in the papermaking direction at a cutoff value of 0.8 mm was used in Example 1, and the surface resin layer was coated. An image material support manufactured in the same manner as in Example 1 except that the thickness is set to 32 μm.

Protective layer (P1): Protective layer for red-sensitive emulsion layer same as that used in Example 1. Protective layer (P2): A protective layer containing fine silica particles in the protective layer (P1) in an anti-blocking amount.

Table 5 shows the obtained results.

[0116]

[Table 5]

[0117] (Note 5) to (Note 7) in Table 5 are as follows.

(Note 5) Roughness of surface resin layer surface: Cut-off value of surface resin layer surface of image material support before coating of undercoat layer is 0.1.
The average surface roughness (μm) in the papermaking direction at 8 mm is shown. (Note 6) Type of top layer: Indicates the type of protective layer of the red-sensitive emulsion layer. (Note 7) Dynamic friction coefficient of the uppermost surface: The dynamic friction coefficient defined in the present invention of the uppermost surface on the image forming side.

From the results shown in Table 5, it can be seen that the image material of the present invention is an excellent image material having good running properties and winding properties, and good cutting accuracy and cutting properties of the image material and its print. You can see that. Among the image materials in the present invention, from the viewpoint of the effect of improving the winding property, those provided with an image forming layer having a dynamic friction coefficient of the uppermost layer on the image forming side in the range of 0.25 or more are preferable.
It is clear that those having an image forming layer in the range of 0.27 or more are more preferable, and those having the image forming layer in the range of 0.29 or more are particularly preferable.

[0120]

According to the present invention, it is possible to obtain an image material having good running properties of the support or the image material during production of the image material, good winding property of the image material, and excellent cutting accuracy and cutting property, and a print thereof. The obtained resin-coated paper-type support for image material, which supports resin-coated paper, which has good running and winding properties, and also has good cutting precision and cutting properties of the image material and its print. Body
An excellent image material can be provided.

Claims (12)

[Claims] An image forming layer of a paper substrate is coated with a resin layer (A) containing a resin (a) capable of forming a film, and the opposite side is formed of a paper having a natural pulp as a main component. A support for an image material coated with a resin layer (B) containing a functional resin (b), wherein the resin layer (B) has a roughened surface and has a backing on the resin layer (B) side. The back layer surface has a center plane average roughness (SRa1) in the papermaking direction at a cutoff value of 0.8 mm measured by a stylus type three-dimensional surface roughness meter (SRa1) of 1.35 μm. ~ 2.35
μm, and the center surface average roughness (SRa2) in the papermaking direction at a cutoff value of 0.025 mm of the back layer surface measured by a stylus type three-dimensional surface roughness meter is 0.20 μm to 0.45 μm.
A support for an image material having a size of μm. 2. The center plane average roughness (SRa1) is 1.40.
2. The support for an image material according to claim 1, wherein the thickness of the support is from μm to 2.05 μm. 3. The center plane average roughness (SRa1) is 1.45.
3. The support for an image material according to claim 2, wherein the thickness is from μm to 1.75 μm. 4. The center plane average roughness (SRa2) is 0.23.
4. The support for an image material according to claim 1, wherein the thickness of the support is from μm to 0.40 μm. 5. A center plane average roughness (SRa2) of 0.26
The support for an image material according to claim 4, wherein the thickness is from μm to 0.35 μm. 6. The support for an image material according to claim 1, wherein the natural pulp is a hardwood kraft pulp. 7. The image material according to claim 1, wherein the natural pulp has a fiber length of the pulp defined below in the range of 0.45 mm to 0.65 mm. Support. Pulp fiber length: A 4 cm × 4 cm paper substrate of an image material support is immersed in 80 cm ³ of a 1.0 N aqueous sodium hydroxide solution for 3 days, and then sufficiently washed with water. Then 3% by weight of water
(Pure water) Put a sufficiently washed paper substrate into a dispersing device (a device that does not cut fibers as much as possible, specifically, a juicer mixer with a rounded blade) so that it becomes a slurry, and stir for 20 minutes. Disintegrate to obtain a pulp slurry. About this pulp, JAPAN TAPPI paper pulp test method No. 52-89 This is a value expressed by a length-weighted average fiber length (mm) measured in accordance with "Paper and Pulp Fiber Length Test Method". 8. The natural pulp has a fiber length of 0.48 mm.
8. The support for an image material according to claim 7, wherein the thickness is in the range of 0.62 mm to 0.62 mm. 9. The natural pulp has a fiber length of 0.50 mm.
9. The support for an image material according to claim 8, wherein the thickness is in the range of 0.5 to 0.59 mm. 10. The natural pulp has a fiber length of 0.53 m.
The support for an image material according to claim 9, which is in a range of m to 0.59 mm. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
11. An image material comprising an image material support provided on the image material support according to 8, 9 or 10. 12. The image material according to claim 11, wherein the image forming layer has a coefficient of dynamic friction of the uppermost layer on the image forming side in a range of 0.25 or more.