JPH04303834A - Diazo copying material - Google Patents

Abstract

PURPOSE:To inhibit the penetration of a coating liq. for forming a photosensitive layer into the base paper of a substrate and to provide a diazo copying material free from grained texture, having high reproducibility and capable of forming a high contrast image. CONSTITUTION:A precoat layer based on silica and a binder is formed on a paper substrate optionally coated with a surface modifying layer based on modified PVA as required and a photosensitive layer based on a diazonium salt and a coupler is formed to obtain a diazo copying material. Pores of 0.1-1.0mum diameter among the fibers of the substrate are distributed by >=50% and the substrate has <0.80ml/g pore volume.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to diazo copying materials.

0002

BACKGROUND OF THE INVENTION In diazo copying materials, the characteristics required of the base paper for support are such that when a diazo photosensitive liquid is applied, the photosensitive liquid partially soaks in and the density becomes high in some areas.
Even if the photosensitive liquid does not penetrate, the adhesion of the photosensitive liquid lacks uniformity, and when color develops, it does not have uneven density or grain, and the desired sensitivity and density are achieved within the allowable range of the applied diazonium salt. and application suitability. In other words, it is better for the image portion of the document to have a higher color density, and for the white portion, it is better to have a uniform plain color without any local fogging. The density of this image area is affected by the type and amount of diazonium salt, but when a specific diazonium salt is used and the same amount is applied, a uniform layer is formed on the surface. It is desirable. In addition, if the thickness of the diazonium salt layer is uneven in some parts of the white background area, or if there are areas where some diazonium salt has soaked into the base paper layer, the decomposition of the diazonium salt will depend on the amount of exposure. Differences occur, and areas with a large amount of diazonium salt, especially areas that have soaked into the base paper layer, remain undecomposed and develop color when developed. These deteriorate the quality of diazo copying paper due to a decrease in contrast, a decrease in sensitivity, and the like. Therefore, conventionally, a precoat layer is provided on the size layer and a diazo photosensitive liquid is applied thereto.

Generally, diazo photosensitive paper uses high-quality paper as a paper support, but a precoat layer containing a polymeric binder and amorphous silica as main components is provided on the support, and a calender is applied depending on the purpose. Processing and other processing may be performed. However, the current situation is that these treatments essentially cannot prevent paper manufacturing irregularities and fiber grain patterns of pulp fibers, which are inherent in paper supports. For example, even if a paper support or a precoat layer provided on a paper support is calendered, the pulp fibers will swell and recover during the immersion process in the coating solution. Furthermore, since hydrophilic silica is used in the precoat layer made of a polymer adhesive and amorphous silica, it is impossible to suppress the pattern of the paper itself. For this reason, special sizing agents and size press processes are being investigated in the papermaking process for diazo base paper.

[0004] Also, as a base paper for a support for diazo copying materials, Japanese Patent Publication No. 61-37612 (Mitsubishi Paper Mills Co., Ltd.)
reported that it is possible to treat the surface using polyoxyethylene polyglyceryl ether as a surface sizing agent to suppress the grain formation caused by local penetration of the coating solution, and that it can also be used as a substitute for a precoat layer. However, diazo copying materials using this base paper have problems such as the occurrence of pulp fiber grain patterns, the density increasing effect of the precoat layer, and the coloring of photolyzed products of diazonium salts. Furthermore, the degree of freedom is limited due to the permeability of the coating liquid, and it lacks versatility.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an excellent diazo copying material which eliminates density unevenness and grain texture.

[0006]

[Means for Solving the Problems] According to the present invention, a precoat layer containing silica and a binder as main components and a photosensitive layer containing a diazonium salt and a coupler as main components are provided on a paper support, if necessary. In the diazo copying material provided with the paper support, the distribution amount of interfiber pores of the paper support having a pore diameter of 0.1 μm to 1.0 μm is 50% or more of the total amount, and the pore volume is 0.8 μm.
A diazo copying material is provided, characterized in that the paper support is a mixture of modified polyvinyl alcohol and one or more emulsion-polymerized hydroxyalkyl (meth)acrylates, styrene and acrylonitrile. In particular, there is provided a diazo copying material provided with a surface-modified layer comprising:

In the diazo copying material of the present invention, the base paper used as the paper support has a pore diameter of 0.1 to 1.
．． The distribution amount of 0 μm is 50% (volume) or more of the whole,
Pore volume measured by mercury penetration amount is 0.80ml/g
It is characterized by being less than If the distribution amount of interfiber pores with a pore diameter of 0.1 to 1.0 μm is less than 50% (volume) of the total and the pore volume is 0.80 ml/g or more, uneven concentration and grain texture will occur. The purpose of the invention is not achieved.

[0008] In producing the base paper of the present invention, wood pulp of softwood, hardwood, etc. is mixed with melamine resin, etc., and after the paper is made in a long copper paper machine etc., it is dried in a dryer, and then subjected to a surface sizing process. acid sizing is carried out,
The fiber pores of the present invention are controlled by setting the dandy roll in the paper machine at an upper position and the lower roller at an oblique angle of 60°.
This can be done by making paper with uniform tension. Further, by adjusting the fiber length of various fibers to 5 mm and the fiber diameter to about 10 tenier, it is possible to optimize the amount of permeation into the pore volume.

As mentioned above, the main component of the base paper is wood pulp, more specifically kraft pulp, but if necessary, fibrous water-dispersible materials such as glass fiber, polyester fiber, polyvinyl alcohol fiber, etc. If so, any of them can be used as an ingredient. The adhesive of the present invention includes polyvinyl alcohol, proteins such as casein, and natural or synthetic water-soluble polymers such as starch derivatives.
Polymer latex adhesives such as polyvinyl acetate and styrene-butadiene, which have excellent adhesion to the pigment's fine particle synthetic silicic acid, can also be used.

The paper support of the diazo copying material of the present invention is mainly composed of modified polyvinyl alcohol obtained by copolymerizing sodium allylsulfonate with base paper, and contains hydroxy (meth)
More preferred is a layered surface modification consisting of a mixture of acrylate, styrene, acrylonitrile with one or two emulsion polymers.

The modified polyvinyl alcohol constituting the surface-modified layer is a copolymer of polyvinyl alcohol containing sodium allylsulfonate in the molecule as shown by the following structural formula 1.

[Chemical formula 1]

The degree of saponification of this modified polyvinyl alcohol is preferably 30 to 85%. In addition, the degree of modification (mol%) of sodium allylsulfonate within the molecule is 0.01~
10 mol% is appropriate. Further, the degree of polymerization of this modified polyvinyl alcohol is in the range of 100 to 1000 without causing any problem to the viscosity. Note that the degree of denaturation (mol%) is l/
It is expressed as (m+l+n)×100.

The emulsion polymer to be mixed with the modified polyvinyl alcohol includes, for example, 5 to 40% by weight of at least one of hydroxyalkyl acrylate and hydroxyalkyl methacrylate, and 5 to 60% by weight of at least one of styrene and acrylonitrile. Examples include copolymers having an average particle diameter of 0.5 to 2.0 μm and a softening point of 60 to 100°C obtained by emulsion polymerization of a monomer mixture containing these as essential components.

[0014] The coating liquid thickness of the surface modification layer is 3 to 50 μm.
is preferred. If it is less than 3 μm, it will not form a surface-modified layer. Moreover, if it exceeds 50 μm, the paper quality will be lost.

As a method for producing the surface modified layer, for example, first a 5 to 20% aqueous solution of a modified polyvinyl alcohol resin is prepared. At this time, those with a saponification degree of 40% will become cloudy, so
Add about 10% alcohol to dissolve. Next, the above-mentioned emulsion is weighed in the same weight ratio and dispersed and dissolved in the above-mentioned aqueous solution. It is coated on a base paper so that the resulting layer has a thickness of 3 to 50 μm, and is gradually dried with hot air at 80 to 120° C. to form a surface-modified layer. For the obtained sample por
As a result of measurement with e Sizer 9310 (Shimadzu Corporation), the pore distribution of 0.1 to 1.0 μm was 85% by volume, and the pore volume at that time was 0.68 ml/g.

A precoat layer containing fine silica powder and a binder as main components is provided on the paper support obtained above. As the binder, it is essential to use a vinyl chloride-acrylic acid ester copolymer resin, but in addition to this, hydrophilic resins such as polyvinyl alcohol, starch, casein, etc. can be used as auxiliary binders. In addition to fine silica powder, auxiliary additives such as starch, concentration reinforcing agents such as organic fillers, and waxes are used, but these are all the same as those conventionally used in pre-coat layers. can be used.

As the diazo compound and coupler (coupling component) used in the photosensitive layer of the present invention, those conventionally used can be used as they are. Examples of the diazo compound include 4-diazo-1-dimethylaminobenzene, 4-diazo-1-diethylaminobenzene,
4-Diazo-1-dipropylaminobenzene, 4-diazo-1-methylbenzylaminobenzene, 4-diazo-
1-dibenzylaminobenzene, 4-diazo-1-ethylhydroxyethylaminobenzene, 4-diazo-1-
diethylamino-3-methoxybenzene, 4-diazo-
1-dimethylamino-2-methylbenzene, 4-diazo-1-benzoylamino-2,5-diethoxybenzene, 4-diazo-1-morpholino-2,5-dibutoxybenzene, 4-diazo-1-ani Linobenzene, 4-diazo-1-dimethylamino-3-carboxybenzene, 4
-Metal halides of chlorides of diazo compounds such as -diazo-1-tolylmercapto-2,5-diethoxybenzene, 4-diazo-1,4-methoxybenzoylamino-2,5-diethoxybenzene (e.g. zinc chloride, Examples include double salts with cadmium chloride, tin chloride, etc.), and salts of the above-mentioned diazo compounds with strong acids such as sulfuric acid, boron tetrafluoride, hexafluorophosphoric acid, etc., but of course they are not limited to these. do not have.

Examples of the coupler include resorcinol, phloroglucin, 2,5-dimethyl-4-morpholinomethylphenol, 3-hydroxycyanoacetanilide, parasulfoacetanilide, 1-benzoylamino-8-hydroxynaphthalene-3,6-disulfone. Amide, 2,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene-3,6-disulfonic acid sodium, 2,3
-Sodium dihydroxy-6-sulfonate, Sodium 1-hydroxynaphthalene-4-sulfonate, 1-amino-3
-hydroxynaphthalene-3,6-disulfonamide,
Naphthol AS, Naphthol AS-D, 2-hydroxynaphthalene-3-biguanide, 2-hydroxy-3-
Naphthoic acid morpholinopropylamide, 2-hydroxy-3 naphthoic acid ethanolamide, 2-hydroxy-3
-Naphthoic acid-N-dimethylaminopropylamide hydrochloride, 2,4,2',4'-tetrahydroxydiphenyl, 2,4,2',4'-tetrahydroxydiphenyl sulfoxide, and the like.

In addition to the above-mentioned materials, various additives commonly used in diazo copying materials can be used in the present invention. For example, development accelerators such as ethylene glycol and toluethylene glycol; storage improvers as sodium naphthalene monosulfonate, sodium naphthalene disulfonate, sodium naphthalene trisulfonate, sulfosalicylic acid, cadmium sulfate, magnesium sulfate, and cadmium chloride. , zinc chloride, etc.: Thiourea, urea, etc. as antioxidants; Caffeine, theopherine, etc. as solubilizers; Citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid, etc. as acid stabilizers can be added as appropriate.

[0020]

[Examples] Examples of the present invention will be shown below. Example 1 (Preparation of paper support of the present invention): The main component pulp was a mixture of 30% softwood pulp, 70% hardwood pulp, and 3% water CSF (Canadian Standard
Freenes) 310 ml was used after being beaten with a pulper, refiner and Jordan. Add the following chemicals to the pulp and use Pearl Gum CS-25S.
1.8% (neutral sizing agent manufactured by Seiko Kagaku Co., Ltd.) ARAFIX 502 0
．． 4% (Fixing agent manufactured by Arakawa Chemical Co., Ltd.) Melamine resin
0.4% urea/formalin resin fine particles
2.0% is mixed to make paper stock, made into paper using a long-term paper machine, and the upper and lower positions of the dandy rolls are set at 60° during the drying process.
It was set to As a surface sizing agent, polyvinyl alcohol 0
．． 6 parts by weight polyacrylamide and hydroxypropyl methacrylate copolymer 0.
8 parts by weight water
A support was obtained by applying 98.6 parts by weight of the solution at a rate of about 1.7 g/m2 using a size press method. The paper surface pH of the support is 6.2, the basis weight is 50 g/m2,
The thickness was 65 μm. The following precoat liquid A was coated on a paper support using a wire bar so that the coating amount after drying was 2 g/m 2 and dried to obtain a precoat layer.

[Pre-coat liquid A]

Fine silica powder (particle size 3μm)
3 parts by weight
Vinyl chloride-2-ethyl hexyl acrylate copolymer (solid content 50wt%, monomer ratio (weight)
PVC: Acrylic ester = 5 0:5
0)
Add 5 parts by weight of water to make the total amount 100 parts by weight. A photosensitive liquid A having the following composition was applied onto the precoat layer and dried to obtain a diazo copying material.

[Photosensitive liquid A]

tartaric acid

1 part by weight caffeine

2 parts by weight Thiourea

1 part by weight naphthalene-2
, 1 part by weight of sodium 7-disulfonate
2-Hydroxy-3-naphthoic acid morpholino propylamide
2 parts by weight 4-morpholino-2,5-dipoxybenzene diazonium chloride 1/2Z
nCl2 2 parts by weight Isopropyl alcohol
1 part by weight saponin

Add water to 0.1 part by weight or more to make 100 ml.

Example 2 A precoat layer was formed in the same manner as in Example 1, but the resin was polyvinyl acetate (solid content 50 wt%) (precoat liquid B). Next, a photosensitive layer was formed in the same manner as in Example 1 to obtain a diazo copying material.

Example 3 Styrene-butyl acrylate copolymer (solid content 50 wt%, monomer ratio (weight) styrene:butyl acrylate = 50:50) was used as the binder resin (precoat liquid C). A precoat layer was formed in the same manner as in Example 1. Next, a photosensitive layer was formed in the same manner as in Example 1 to obtain a diazo copying material.

Example 4 Vinyl chloride-ethyl acrylate copolymer (solid content 50 wt%, monomer ratio (weight) vinyl chloride:ethyl acrylate = 20:80) was used as the binder resin (pre-coat liquid D).
) A precoat layer was formed in the same manner as in Example 1 except for the following. Next, a photosensitive layer was formed in the same manner as in Example 1 to obtain a diazo copying material.

Example 5 [Preparation of paper support of the present invention]: The same pulp as in Example 1 was used as the main component pulp, and the same neutral size process was adopted. Paper was made using a Fourdrinier paper machine, and the upper and lower dandy roll positions during the drying process were set at 60°. Next, as a surface sizing agent, rosin sizing agent (for pulp) 1.8% sulfuric acid band (same as above) 0.4%
Melamine resin (same as above) 0.4
%Urea/Formalin (same as above) 2.0%
Resin fine particles The comparative support has a paper surface pH of 3.6, a basis weight of 50 g/m2,
The thickness was 65 μm. Example 1
A precoat layer similar to that described above was formed and a photosensitive layer was applied to obtain a diazo copying material.

Comparative Example 1 Using the same paper stock as in Example 1, paper was made using a long-term paper machine.As a surface sizing agent, P
G-O (polyoxyethylene polyglyceryl ether)
0.5% by weight water

A support was obtained by applying a 99.5% by weight solution at a rate of about 1.7 g/m2 using a size press method. The paper surface pH of the support was 6.2, the basis weight was 50 g/m2, and the thickness was 65 μm. The precoat layer and photosensitive layer of Example 1 were formed on the paper support obtained above to obtain a diazo copying material for comparison.

Comparative Example 2 The same pulp and chemicals as in Example 1 were used in combination, the paper was made using a fourdrinier paper machine, and after a drying process, the top and bottom angles of the dandy rolls were placed at 120° for drying. The paper surface pH of the support (same as Example 1 except for the dandy roll angle) was 6.
．． 2. The basis weight was 5 g/m2 and the thickness was 6.9 μm. The pre-photosensitive layer of Example 1 was formed on this diazo paper to obtain a diazo copying material for comparison.

Next, Examples 1 to 5 and Comparative Examples 1 to 2
The sample obtained was visualized using Ricopy SD598 (manufactured by Ricoh Co., Ltd.), and the grain texture and image density were measured. The results are shown in Table 1. In addition, the paper support may be micro. Meritic
The pore diameter of the pulp fibers and the amount of mercury permeation were also measured using a poresizer-9810 manufactured by S Company. The maximum concentration was measured using Macbeth RD-914.

[0028]

[Table 1]

Example 6 The following surface-modified resin liquid A was applied to a thickness of 5 μm on the base paper (basis weight 62 g/m2) support obtained in Example 1, and dried with hot air at 80 to 120°C. A surface modified layer was formed (water content in paper: 5%). [Surface modified resin liquid A] Sodium alysulfonate modified polyvinyl alcohol (degree of modification 0.04 mol%,
10g of saponification degree 43%, polymerization degree 200) was taken, and after addition, the liquid temperature was maintained at 80°C while stirring, and left for 30 minutes. After that, lower the liquid temperature to 40℃ and add 1 liter of isopropyl alcohol.
When 0g is added, it becomes a clear liquid. Emulsion polymerization was carried out using monomer units of 20% by weight of hydroxyethyl acrylate and 80% by weight of acrylic styrene (RE-4 manufactured by Mitsui Heavy Pressure Co., Ltd.).
141, Tg 22°C) was added and mixed and dispersed. This liquid was used as surface-modified resin liquid A. Next, the following photosensitive liquid B was applied to the surface of the surface-modified paper obtained above at a concentration of 12.5 ml/m2, and heated with hot air at 80°C. It was gradually dried to obtain a diazo copying material. [Photosensitive liquid B] Tartaric acid
1
0g isopropyl alcohol
10g
2-Hydroxy-3-naphthoic acid-
Morpholinopropylamide
10g 4-morpholino-2,5-dibutoxybenzene diazonium chloride/1/2 zinc chloride
10g zinc chloride

10g Syloid-244 (manufactured by Fuji Davison) 10g water

940g

Example 7 The following photosensitive paper C was coated on the surface of the surface-modified paper obtained in Example 6 using the same photosensitive liquid-coated paper as in Example 6, and dried to obtain a diazo copying material.

[Photosensitive liquid C]

tartaric acid
1
0g isopropyl alcohol
10g
2-Hydroxy-3-naphthoic acid-
Morpholinopropylamide
10g 4-morpholino-2,5-dibutoxybenzene diazonium chloride/1/2 zinc chloride
10g zinc chloride

10g Syloid-244 (manufactured by Fuji Davison) 10g water

940g

Example 8 On the support of the base paper (basis weight: 82 glm2) obtained in Example 1, the following surface-modified resin liquid B was applied to a thickness of 5 μm and dried with hot air at 80 to 120°C. (Moisture in paper 5%) [
Surface modified resin B] Sodium allyl sulfonate modified polyvinyl alcohol (saponification degree 50%, polymerization degree 500
), and after addition, keep the liquid temperature at 80°C while stirring and leave for 30 minutes. After that, lower the liquid temperature to 40℃,
Adding 10g of isopropyl alcohol will result in a clear liquid. Here, emulsion polymerization was carried out using monomer units of 20% by weight of hydroxyethyl acrylate and 20% by weight of acrylnitsol (RE-4141 manufactured by Mitsui Toatsu Co., Ltd., Tg 22°C).
) was added, mixed and dispersed, and this liquid was designated as surface-modified resin liquid B. Next, the following precoat liquid A was coated on the surface-modified paper using a wire spar so that the coating amount after drying would be 2 g/m 2 and dried to obtain a precoat layer. [Pre-coat liquid] Fine silica powder (particle size 3 μm)
3 parts by weight
Vinyl chloride-2-ethylhexyl acrylate copolymer (solid content 50 wt%, monomer ratio (weight) vinyl chloride:
Acrylic acid ester = 50:50
) Add 5 parts by weight of water to make a total amount of 100 parts by weight. A photosensitive liquid having the composition shown below was coated on the precoat layer and dried to obtain a diazo copying material. [Photosensitive liquid A] Tartaric acid
1
0g caffeine

2g Thiourea

10g Sodium naphthalene-2,7-disulfonate 10g 2-hydroxy-3-naphthoic acid morpholino propylamide
20g 4-morpholino-2,5-dipoxybenzene diazonium chloride・1/2Zncl2 20g
Isopropyl alcohol
10g
sabonin
Add water to 1g or more to make 1 liter.

Example 9 A diazo copying material was obtained in the same manner as in Example 6 except that the following photosensitive liquid D was used. [Photosensitive liquid D] Tartaric acid
1
0g caffeine
2
0g Thiourea

10g Sodium naphthalene-2,7-disulfonate 10g 2-hydroxy-3-naphthoic acid morpholino propylamide
20g 4-morpholino-
2,5-dibutoxybenzene diazonium chloride/1/2ZnCl2 20g
Isopropyl alcohol
10g S
ylod-244 (Fuji Davison)
20g water

930g

[0033]

[Example 10] The following surface-modified resin liquid C was applied to the support of the paper (52 g/m2 basis weight) obtained in Example 1 to a thickness of 10 μm.
It was coated and dried (moisture content in the paper was 5%). [Surface modified resin liquid C] Sodium allylsulfonate modified polyvinyl alcohol (degree of modification 0.5 mol%,
After adding 10 g of saponification degree 53 mol %, polymerization degree 300), the liquid temperature was maintained at 80° C. with stirring and left for 30 minutes. Thereafter, the liquid temperature was cooled to 25° C., and emulsion polymerized (manufactured by Mitsui Toatsu Co., Ltd.) was mixed and dispersed at a monomer ratio of 20% by weight of hydroxybutyl acrylate and 20% by weight of acrylic styrene. Next, apply 1 portion of the following photosensitive liquid E to the surface of the surface-modified paper obtained above.
It was coated at a concentration of 2.5 ml/m2 and gradually dried with hot air at 80°C to obtain a diazo copying material. [Photosensitive liquid E] Tartaric acid
1
0g isopropyl alcohol
10g
2-Hydroxy-3-naphthoic acid amide
-γ-diethylaminoethyl oxide
10g 4-dimethylaminobenzenediazonium chlorado・1/2 zinc chloride 10
g Zinc chloride
1
0g Sylod-244 (manufactured by Fuji Davison) 10g water

940g

Example 11 Before applying the photosensitive liquid E, the following pre-coat liquid E was applied to
．． After coating with a wire bar to give a concentration of 0 ml/m2 and drying with hot air at 80°C, photosensitive liquid C similar to that in Example 10 was coated to obtain a diazo copying material. [Precoat liquid E] Sylod-244 (manufactured by Fuji Davison)
40g Vinyl acetate S-6
l (Showa Kobunshi Kagakusha) 50g
water
910g

Comparative Example 3 A sample coated with the following surface-modified resin liquid D in the same process as in Example 1 was coated with photosensitive liquid B of Example 6 in the same amount, dried, and a comparative diazo copying material was obtained. I got it. [Surface modified resin liquid D] 20 g of polyvinyl acetate S-61 (solid content 43%) manufactured by Showa Kobunshi Kagaku Co., Ltd. was mixed with 8 g of water (25°C
) is obtained by stirring and dispersing.

Comparative Example 4 A sample coated with surface-modified resin liquid E in the same process as in Example 6 was coated with photosensitive station B of Example 6 in the same amount, dried, and a comparative diazo copying material was obtained. I got it. [Surface Modified Resin Liquid E] 20 g of polyvinyl chloride emulsion manufactured by Nissin Chemical Co., Ltd. was stirred and dispersed in 80 g of water (25° C.).

Comparative Example 5 Syloid-244
20g polyvinyl alcohol (degree of saponification 70%, degree of polymerization 500) 10g water

70g of the above pre-coat solution was applied to diazo copy base paper (basis weight 58g/m2) to a thickness of 5μm, and
It was dried with hot air at 0°C to 120°C. The photosensitive solution B of Example 6 was applied to this precoated paper and dried in the same process to obtain a diazo copying material for comparison.

The pore distribution of the surface-modified papers of Examples 6 to 11 and Comparative Examples 3 to 5 was measured using a poresizer 9310 (Shimadzu Corporation). In addition, the diazo copying materials of Examples 6 to 11 and Comparative Examples 3 to 5 were used with Recopy SD-580.
(manufactured by Ricoh Co., Ltd.), and density unevenness and grain texture were visually judged based on uniformity of halftones. Also, pores
The pores between fibers and the amount of mercury permeation in the paper support after surface modification were measured using IZER9310. These results are shown in Tables 2 and 3. Excellent: 1 Good: 2 Fair: 3 Poor: 4

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

Effects of the Invention The diazo copying material of the present invention suppresses the penetration of the photosensitive layer coating liquid, provides diazo copy paper with no grain texture, provides high contrast copy images with high reproducibility of the original, and eliminates density unevenness. Does not give high density images.

Claims (3)

[Claims] Claim 1. A diazo copying material comprising, on a paper support, a precoat layer containing silica and a binder as main components, and a photosensitive layer containing a diazonium salt and a coupler as main components, as required. The pore diameter of the interfiber pores of the support is 0.
．． A diazo copying material characterized in that the distribution amount of 1 μm to 1.0 μm is 50% or more of the total amount and the pore volume is less than 0.80 ml/g. [Claim 2] As a paper support, modified polyvinyl alcohol, hydroxyalkyl (meth)acrylate,
2. The diazo copying material according to claim 1, wherein the diazo copying material is provided with a surface-modified layer comprising a mixture of one or two emulsion polymers of styrene and acrylonitrile. 3. The diazo copying material according to claim 2, wherein the modified polyvinyl alcohol is a saponified product of a copolymer of vinyl acetate and sodium allylsulfonate.