JPS60154252A - Light-shielding photographic resin-coated paper - Google Patents

Abstract

PURPOSE:To obtain a light-shielding photographic resin-coated paper extremely small in occurrence of black gel by coating the surface of a paper base or synthetic paper base with a resin compsn. consisting of 2 kinds of polyolefin resins different in melt index and carbon black. CONSTITUTION:A master batch contg. a carbon black is prepared by incorporating carbon black, such as furnace black or channel black, in a polyolefin resin, such as low density PE, having a melt index of 5-60 at 190 deg.C in an amt. of 5-50wt% of the PE. The obtained master batch is diluted with a polyolefin resin, such as low-density PE, having a melt index of 2-9 at 190 deg.C, and an intended light-shielding photographic resin-coated paper is obtained by melt extruding said obtained resin compsn. and coating a paper or synthetic paper base with a melt extruding machine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light-shielding photographic resin-coated paper, and more particularly, to a light-shielding photographic resin-coated paper that generates very little black gel.

It is well known that up until now, carbon black has been applied to light-shielding supports and light-shielding packaging materials as water-based paints or organic solvent-based paints. It has also come to be used as a light-shielding support by incorporating carbon black into the material.

Normally, in order to make light-shielding photographic resin-covered paper using carbon black, a Shinkai masterbatch (hereinafter sometimes abbreviated as MB) is used, which is a method in which carbon black is contained in a thermoplastic resin such as polyethylene resin at a high concentration. Create and
It is diluted and mixed with a diluted resin to a desired ratio and then melt-extruded and coated on a support such as paper using a melt extruder, or a so-called compound is prepared by containing carbon black in a desired composition ratio from the beginning in a resin. It has been done to prepare and apply it to a support as well by means of a melt extruder.

However, in this case, the carbon black is extremely difficult to tolerate in the resin, and when large particles of carbon black are extruded from a melt extruder and coated on a support such as paper, the carbon black becomes large. Since the thickness of the resin layers before and after the particles becomes thinner, the black density decreases significantly, and in severe cases, the resin layer may crack (resin cracking) and the surface of the support itself may be exposed.

Normally, carbon black-containing resin-coated paper is often used as a light-shielding material for photographs, etc., and if carbon black concentration is not restricted or resin cracks occur as described above,
It no longer functions as a light shield at all, and becomes a fatal flaw.

In addition, the relatively large carbon black particles contained in the resin layer are coated with a resin layer (the side to which photographic emulsion is usually coated) containing, for example, titanium dioxide pigment, on the opposite side of the support via a melt extruder. When installed, the carbon black particles in the black resin layer affect the @ surface of the titanium dioxide pigment-containing resin layer due to strong pressure bonding between the cooling roll and the press roll, causing convexities on the surface of the titanium dioxide pigment-containing resin layer. Because of the formation of protrusions, it became unusable as a photographic support. Of course, a photographic emulsion or the like is coated on the black resin layer containing carbon black.

When used as a support for printing, it causes uneven coating, emulsion repellency, etc., so even in this case, it cannot be used again.

The black gel referred to in the present invention is the black gel that is generated in the black resin layer when carbon black is applied to the resin-coated paper for light-shielding photographs, which has an adverse effect on the resin-coated paper for light-shielding photographs. Refers to carbon black particles.

The present inventors conducted intensive research to solve this problem, and as a result, they arrived at the present invention.

That is, the present invention provides a photographic resin-coated paper in which at least one surface of a paper or synthetic paper substrate is coated with a resin composition comprising at least carbon black and a resin, wherein the resin composition comprises: (1) carbon black; (2) Carbon black (3) The masterbatch diluent resin containing carbon black has a melting index of 2 to 9 at 190°C. A light-shielding photographic resin-coated paper made of polyolefin resin is provided.

The light-shielding photographic resin-coated paper of the present invention has extremely little black gel, and provides a suitable light-shielding resin-coated paper.

The melt index in the present invention is the melt index (MI
) has the same meaning as

The melting index (hereinafter sometimes abbreviated as MI) of the resin for MB used in the present invention is preferably from 5 to 60, preferably from 7 to 45. For these MIs, suitable MI polyolefin resins are selected depending on the type of carbon black used, particle size, amount of carbon black contained in MB, etc.

The carbon black used in the present invention may be produced by any production method such as a furnace method, a channel method, or a thermal method, but carbon black produced by a furnace method is often used in the present invention. There are no particular restrictions on the shape and particle size of the carbon black used, and the quality required by the light-shielding photographic resin-coated paper,
For example, a carbon black is selected that satisfies all aspects such as hiding power. In the present invention, for example, Mitsubishi Kasei Carbon Black Na5, Na20, Na33, Na40. Su44,+
45, +52, MA8, MAloo, +900, +10
00, ◆2200B, Su2350, Na2400B, etc. are used.

The carbon black content contained in MB is 5 to 50
Parts by weight, preferably 5 to 30 parts by weight. M.B.
If the carbon content exceeds 50 parts by weight, MBlli
Not only does the dispersion in the resin deteriorate during manufacturing, but even if the relatively low MI diluent resin of the present invention is used for melt extrusion coating, the generation of black gel cannot be well prevented.

The carbon black-containing MB in the present invention can be prepared using a conventional melt kneader such as a Banbury mixer or a kneader. In addition to polyolefin resins and carbon black, fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate, sium stearate, zirconium octylate, sodium valmitate, calcium valmitate, sodium laurate, etc. can also be used.

The amount added is preferably in the range of 0.01 to 5% by weight based on the resin composition containing carbon black. Furthermore, in addition to these fatty acid metal salts, antioxidants can also be used alone or in combination with fatty acid metal salts.

In the present invention, hindered phenolic antioxidants are particularly suitable. For example 1.3.5-)IJ methyl-2
,4,6-tris(3,5-di-tert-butyl-4
-hydroxybenzyl)benzene, tetrakis[methylene (3,5-di-tert-butyl-4-hydroxy-
hydrocinnamate)] methane, octadecyl-3,5
-di-tert-butyl-4-hydroxy-hydrocinnamate, 2.21.211-trix(3,5-9-t
ert-7°f#-4-1? )”Oixyphenyl)globionyloxy]ethyl isocyanurate, 1.3.
5-) Lis(4-1ert-butyl-3-hydroxy-
2,6-di-methylbenzyl)isocyanurate, tetrakis(2,4-tart-phthylphenyl)4.
4'-biphenylene diphosphite, 4,4'-thiobis-(6-tert-butyl-0-cresol),
2.2'-Thiobis-(6-1crt-butyl-4-methylphenol), tris-(2-methyl-4-hydroxy-5-teft-butylphenyl)butane 1.2.
2'-methylene-bis-(4-methyl-6-tert-
butylphenol), 4,4'-methylene-bis-(2
, 6-tert-butylphenol) 1.4.4'
-Butylidenebis-(3-methyl-6-tret-butylphenol), 2.6-tert-butyl-4-
Methylphenol, 4-hydroxy methyl-2,6-
Sheet-tert-butylphenol.

2.6-tert-butyl -4-n-butylphenol etc. can be used.

Also, depending on the properties of the antioxidants, two or more antioxidants may be used in combination. The content of the antioxidant in the photographic resin composition is 5 to 150 ppm, preferably 5 to 100 ppm in 100 parts by weight of the resin composition.
It is 69 ppm, more preferably 5 to 50 ppm.

The polyolefin which is the resin for diluting the carbon black-containing masterbatch used in the present invention preferably has a number of 2 to 9, preferably 2 to 7, and most preferably 2 to 5.

As in the present invention, the MIt of the carbon black-containing MB resin is relatively high, while the MIt of the MB diluting resin is
It is still unclear why the generation of black gel is suppressed when the resin composition, which has a relatively low molecular weight, is applied to light-shielding photographic resin-coated paper by melt extrusion coating, but in any case, This is thought to be due to a synergistic effect between the two. Furthermore, it has been found that the generation of black gel can be even more effectively suppressed by using a fatty acid metal salt and/or an antioxidant as a decoy.

The carbon black content in the black resin layer containing carbon black of the light-shielding photographic resin-coated paper of the present invention depends on the required quality, the degree of hiding power, the thickness of the black resin layer, etc. Although it can be varied as appropriate, it is usually 1 to 20 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the resin composition.
Parts by weight.

The light-shielding photographic resin-coated paper containing the light-shielding photographic resin composition of the present invention in at least one resin layer is prepared by heating and melting the light-shielding photographic resin-coated paper on a normally running paper or synthetic paper base (hereinafter simply referred to as base paper). It is manufactured by melt-extruding a resin composition into a film through a slit die. Usually, the melt extrusion temperature is preferably 200°C to 350°C. Also,
Before applying the resin composition to the base paper, it is preferable to subject the base paper to an activation treatment such as a corona discharge treatment or a fire treatment. There is no particular restriction on the thickness of the resin layer of the light-shielding photographic resin-coated paper, but it is advantageous to extrude coat each resin layer to a thickness of generally about 5 microns to 50 microns. In addition, in ordinary resin-coated paper in which both sides of the base paper are coated with resin, the black resin layer is on the opposite side across the base paper, that is, the resin surface containing titanium dioxide pigment etc. (usually photographic emulsion is Depending on the application, the surface to be coated may be a glossy surface or
It has a matte surface, a silky surface, etc., and can be subjected to activation treatment such as corona discharge treatment or fire treatment on the front surface or both front and back surfaces as necessary. Furthermore, another resin layer may be provided on the black resin layer.

The base paper used in the practice of the present invention is ordinary natural pulp paper,
Although synthetic fibers or so-called synthetic paper made of synthetic resin film may be used, natural pulp paper whose main component is wood pulp such as softwood pulp, hardwood pulp, or mixed pulp of softwood and hardwood is advantageously used. There are no particular restrictions on the thickness of the base paper, but base paper with a smooth surface is preferred, and its basis weight is 50 to 250 t/rd.
is preferred.

The base paper mainly composed of natural pulp, which is advantageously used in the practice of the present invention, can contain various polymer compound additives. For example, dry paper strength enhancers include cationized starch, cationized polyacrylamide, anionized polyacrylamide, carboxy-modified polyvinyl alcohol, gelatin, etc.; sizing agents include fatty acid salts,
Rosin-conductor, dialkyl ketene dimer emulsion, petroleum resin emulsion, ammonium salt of styrene-maleic anhydride copolymer alkyl ester, etc., as well as pigments, clay 1
．． Kaolin, calcium carbonate, barium sulfate, titanium oxide, etc., as wet paper strength agents, melamine resin, urea resin, epoxidized polyamide resin, as fixing agent, polyvalent metal salts such as aluminum sulfate, aluminum chloride, cationized starch, etc. cation-modified polymeric acid, pH adjusters such as caustic soda, soda carbonate, hydrochloric acid, etc., inorganic electrolytes such as common salt, mirabilite, and other suitable combinations of dyes, fluorescent brighteners, latex, and the like.

The light-shielding photographic resin-coated paper to which the light-shielding photographic resin composition of the present invention is applied can be provided with various I/silver halide photographic emulsion layers. For example, it can be used as a support for ordinary color emulsions, black and white emulsions, etc., but it can also be used as a support for planographic printing using the silver salt diffusion transfer method called a master material, and as a negative photosensitive material for printing plates. can also be used. The light-shielding photographic resin-coated paper of the present invention can provide a suitable color print, especially when used as a support for an image-receiving layer in a diffusion transfer method.

In addition, on the back side of the photographic resin-coated paper in the present invention, that is, on the support surface opposite to the side on which the photographic constituent layer, often the silver halide tetragonal constituent layer or the image-receiving layer, is coated, there is a curl. It is possible to install a coating layer consisting of a hydrophilic colloid layer called a back coat layer for the purpose of preventing static electricity, preventing adhesion, and preventing slipping. Such a back coat layer may contain a binder, a protective colloid, a curing agent, an antistatic agent, a surfactant, a matting agent, a latex, and the like.

Next, examples will be described in order to explain the present invention more specifically.

Example 1 Low-density polyethylene (
Density 0.91'8 fA37□0 parts by weight was taken into a bar/six mixer Φ p1 Add carbon black + manufactured by Mitsubishi Kasei to this.
30 parts by weight of 30i was added and thoroughly kneaded at 150°C to obtain carbon black-containing MBs.

On the other hand, a mixed paper stock of 50 parts by weight of hardwood bleached kraft pulp and 50 parts by weight of softwood bleached sulfide pulp was beaten to Canadian Standard Freeness 310-, and to 100 parts by weight of pulp, 3 parts by weight of cationized starch and anionic 0.2 parts by weight of polyacrylamide, alkyl ketene dimer emulsion (as ketene dimer content)
0.4 parts by weight of polyaminopolyamide epichlorohydrin resin and 0.4 parts by weight of polyaminopolyamide epichlorohydrin resin were added to form paper having a basis weight of 160 f/d. The obtained wet paper paper was dried at 110°C, and then added with 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent brightener, 0.002 parts by weight of blue dye, 20.2 parts by weight of citric acid, and 97 parts by weight of water. The substrate was impregnated with an impregnating solution consisting of 100 ml of resin for 25°C, dried with hot air at 110°C, and calendered at a linear pressure of 90 Kp/m, and then subjected to corona discharge treatment on both sides to form a base paper for photographic resin-coated paper. Manufactured.

Next, 1 part by weight of each of the above-mentioned MBs was collected, and then 99 parts by weight of each MB diluent resin listed in Table 1, Note 2 was collected, and each resin composition of the combinations listed in Notes 1 and 2 of Table 1 was obtained. were obtained respectively.

After thoroughly mixing each of these resin compositions, a screw set extruder with an extrusion port diameter of 65+m and a 750m
Using a melt extruder with a wide T-die, the resin temperature was 32.
Resin Jlj30 at 0°C and screw rotation 1100 rpm.
Melt extrusion coating is applied so that μ is obtained. The number of black gels generated on the resin surface containing carbon black was visually counted.

The results obtained are shown in Table 1.

From the results in Table 1, the M of carbon black-containing low density polyethylene for MB (hereinafter sometimes abbreviated as LDPE)
Those with I of 3.4 and 65 are combinations with LDPE for all MB dilutions with MI of 2.4 to 10 -tK:Th''-'QJ
! ``# (7) issue'' is strange and too many'' is 01.

On the other hand, if the MI of LDPE for MB is 5 to 45 and □MB
It can be seen that in all combinations of resin compositions in which the MI of the LDPE for dilution is 2.4 to 5, the generation of black gel is suppressed to a greater extent. Also, even if LD for MB
PE's MI is.

-□Table 1' □“ 1, Low density polyethylene for M B (density 0.918
t, (d) 2, Low density polyethylene for MB dilution (density 0.918tE) 16- Even if it is 5 to 45, the MI of LDPE for MB dilution is 10
It can be seen that black gel is generated frequently in all combinations of resin compositions.

Sokote, 30 parts by weight of each MB of A4.5.7.8.10, 11.13.14 and the corresponding Table 1 of the same store,
After taking 70 parts by weight of each diluent LI) PE described in Note 2 and mixing them thoroughly, the resin was injected onto one side of the base paper at a melting temperature of 320°C to a resin thickness of 20 μm using the melt extruder described above. Melt extrusion coating is applied to achieve the desired results. Next, apply low-density polyethylene (density 0.918 f/d,
MI=5) was melt-extruded and coated using a melt extruder at a resin temperature of 330° C. so that the resin thickness was 20 μm.

The light-shielding photographic resin-coated paper produced in this manner had little generation of black gel and was suitable as a support for lithographic printing plates.

On the other hand, for comparison, resin-coated paper for light-shielding photographs made using A6 and 1616 in exactly the same manner as described above had a lot of black gel and was not suitable as a support for lithographic printing plates.
It was inappropriate.

Example 2 Similarly to Example 1, LDPE (density 0.918f and 1M
I=20) and Carbon Placuna 2300 manufactured by Mitsubishi Kasei were placed in a Banbury mixer and thoroughly kneaded at 150°C to obtain carbon black-containing MB, respectively.

Next, each resin composition of the combination described in Notes 1 and 2 of Table 2 was added so that the carbon black content in the resin composition was 0.3 parts by weight based on 100 parts by weight of the resin composition. Obtained.

Thereafter, the number of black gels was counted using the same procedure as in Example 1.

The results obtained are shown in Table 2.

From the results in Table 2, the occurrence of black gel is extremely small in all cases other than A24 and A27;
It can be seen that No. 27 has a large amount of black gel. The carbon black content is 6096 (427), even if MB
The MI of LDPE for dilution is shown in Table 2 Note) 1. Even if carbon black φ2300 2 and LDPR for dilution MB (density 0.918) 2 are used, the generation of black gel cannot be well suppressed. I understand.

Next, each MB of 421.22.23.25.26 and its corresponding LDPE of each MI listed in Table 2, Note 2
and the like so that the carbon black content in the resin composition was 2.5 parts by weight based on 100 parts by weight of the resin composition, and after mixing well, the same procedure as in Example 19-1 was carried out. A light-shielding photographic resin-coated paper was obtained. The light-shielding photographic resin-coated paper produced in this manner was suitable as a negative light-sensitive material for printing plates with little generation of black gel.

On the other hand, for comparison, light-shielding photographic resin-coated paper made using A24 and A27 in exactly the same manner as described above had a significant amount of black gel, making it unsuitable as a negative photosensitive material for printing plates. .

Example 3 In the same manner as in Example 1, the mixture was placed in a Banbury mixer so as to have the compounding ratios shown in Table 3, Notes 1 to 4, and thoroughly kneaded at 150°C to obtain MB containing carbon black and the like.

Next, each resin composition of the combination described in Notes 1 to 5 of Table 3 was obtained such that the carbon black content in the resin composition was 0.3 parts by weight based on 100 parts by weight of the resin composition. .

The number of black gels was determined by following the same procedure as in the example.

The results obtained are shown in Table 3.

-20 = Table 3 Note) 1. LDPE for MB (density 0.918) 2. Carbon Plakna 403 manufactured by Mitsubishi Kasei, Zinc stearate (Zn-at) content in MB 4, Antioxidant in MB (A1
0) containing mold A10 is tetrakis [methylene (3,
5-tert-phthyl-4-hydroxy-hydrocinnamate comethane 5, LDPR for MB dilution (5 degrees 0.918) From the results in Table 3, all of A31 to 39 have less black gel generation, especially It can be seen that those containing zinc stearate and/or an antioxidant produce even less black gel.

Next, 15 parts by weight of each MB from Flats 31 to 39 and 85 parts by weight of LDPE described in Table 3 and Note 5 were respectively taken and mixed well, and then the above carbon black etc. was applied to the back side of the base paper described in Example 1. The resin composition containing the resin composition was melt-extruded and coated to a resin thickness of 30μ, and titanium dioxide pigment 1 was further coated on this black resin 1-.
A resin layer containing 0 parts by weight (the formulation will be described later) has a resin thickness of 30 μm.
Apply by melt extrusion so that Next, on the opposite side of the base paper, a resin layer containing 14 parts by weight of titanium dioxide pigment (the formulation will be described later) was applied by melt extrusion so that the resin thickness was 30μ. A light-shielding photographic resin-coated paper was obtained in the same manner as above.

In addition, the resin composition for the back surface was prepared in a Banbury mixer using an LD.
50 parts by weight of PE (density 0.918, MI=9), 50 parts by weight of anatase titanium dioxide pigment and 2.5 parts by weight of zinc stearate were mixed well at 150°C to obtain MB containing titanium dioxide pigment etc. Obtained. 20 parts by weight of this MB and LDPE for diluting MB (density 0.918, MI=
5) 80 parts by weight are thoroughly mixed and used as a resin composition for the back side. The surface resin composition was prepared in a Banbury mixer with 50 parts by weight of LDPE (density 0.91B, MI=9), 50 parts by weight of anatase titanium dioxide pigment, 2.5 parts by weight of female zinc thearate, and 0.2 parts by weight of ultramarine. Take the part, 1
The mixture was thoroughly kneaded at 50° C. to obtain MB containing titanium dioxide pigment and the like.

28 parts by weight of this MB and LDPE for diluting MB (density 0.
918, MI=9) were thoroughly mixed and used as a surface resin composition.

An image receiving layer is provided on the surface resin layer (the layer on the opposite side to the black resin layer containing carbon black) of the A31-39 light-shielding photographic resin-coated paper obtained in this way, and the image receiving layer is used in the diffusion transfer method. When used as a support for printing, suitable color prints were obtained with little generation of black gel.

Example 4 The zinc stearate in Example 3 was replaced with magnesium stearate, and the antioxidant in Example 3 was replaced with 1.3.5-)lith(4-tert-butyl-3-
A light-shielding photographic resin-coated paper obtained in the same manner as in Example 3 except that hydroxy-2,6-di-methylbenzyl)in cyanurate was used was used for the image-receiving layer in the diffusion transfer method in the same manner as in Example 3. When used as a support, a suitable color print was obtained with little generation of black gel (same as in Example 3).

24- Procedural amendment (1) 1980, U/D Director General of the Japan Patent Office Young L* ~ (Moe 1, Indication of the case 3, Relationship of the person making the amendment to the case Patent Applicant 4, Residence of the agent Mitsubishi Paper Mills Co., Ltd., 3-4-2 Marunouchi, Chiyoda-ku, Tokyo 100, Japan Tel: (213) 3641 Detailed Description of the Invention Column 8, Contents of Amendment 5IllII) Kuranobu, this Meisai wo Tomoe tδ・Supplementary information.

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) fl,'! The light-shielding photographic resin-coated paper described in item 2.

Attachment The scope of claims is amended as follows.

"10 A photographic resin-coated paper in which at least one side of a paper or synthetic paper substrate is coated with a resin composition comprising at least carbon black and a resin, wherein the resin composition comprises: (1) a carbon black-containing masterbatch; The resin for
Low-density polyethylene resin (2) having a melting index of 5 to 60 at 190°C Carbon black (3) The carbon black-containing masterbatch diluent resin is made of a low-density polyethylene resin having a melting index of 2 to 9 at 190°C. Light-shielding photographic resin-coated paper.

A light-shielding photographic resin-coated paper according to claim 1.

Claims 1-4, wherein the carbon black-containing masterbatch contains a fatty metal salt;
The light-shielding photographic resin-coated paper according to claim 2, which contains a dophenol-based antioxidant. ”

Claims (1)

[Claims] 1. A photographic resin-coated paper in which at least one surface of a paper or synthetic paper substrate is coated with a resin composition consisting of at least carbon black and a resin, wherein the resin composition is (1) ) Polyolefin tree JII in which the carbon black-containing masterbatch resin has a melting index of 5 to 60 at 190°C (2) Carbon black (3) The carbon black-containing masterbatch diluting resin has a melting index of 2 to 60 at 190°C A light-shielding photographic resin-coated paper made of polyolefin resin No. 9. 2. The light-shielding photographic resin-coated paper according to claim 1, wherein the polyolefin resin is a polyethylene resin. 3. The light-shielding photographic resin-coated paper according to claim 1 or 2, wherein the carbon black content in the carbon black-containing masterbatch is 5 to 50 parts by weight. 4. The light-shielding photographic resin-coated paper according to claim 3, wherein the carbon black-containing masterbatch contains a fatty acid metal salt. 5. The light-shielding photographic resin-coated paper according to claim 3, wherein the carbon black-containing masterbatch contains a hindered phenolic antioxidant.