JPH1055042A - Photographic support and photographic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance adhesion between a polymer and an emulsion and to lower a curling tendency of a photographic printing paper by using a polyolefin layer subjected to frame anealing at a temperature higher than the Vicat softening point of a polyolefin. SOLUTION: The polyolefin layer is subjected to a frame anealing at a temperature higher than the Vicat softening point of the polyolefin. The photographic printing paper coated with a thermoplastic resin is subjected to the frame anealing treatment by a method of heating a thermoplastic resin at a temperature higher than its Vicat softening point. This treatment enhances an adhesion between the polymer and the emulsion and lowers an emigration of a fluorescent whitening agent and also improves curling, and the thermoplastic resin is gradually cooled and the polymer molecules are relived, permitting a free volume in the polymer to be reduced, and emigration of a fluorescent whitening agent to be reduced by reduction of a free volume and a density of the processed face and a modulus to be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a photographic printing paper coated with a thermoplastic resin by extrusion coating, and more particularly, to a photographic emulsion having improved curling resistance and reduced migration of an optical brightener. The present invention relates to a method for producing a photographic printing paper coated with a thermoplastic resin, which has better adhesiveness with a photographic paper.

[0002]

BACKGROUND OF THE INVENTION As is known in the art, photographic paper is coated with one or more polyolefin layers, preferably by hot-melt extrusion as known in the art. I do. The polyolefin can be any applicable polyolefin material known in the art. Representative examples of these materials are low and high density polyethylene and polypropylene.

When a polyolefin is coated on the photographic emulsion layer-coated surface of photographic paper, the polyolefin is preferably
It is a low-density polyethylene having a density of 0.91 to 0.93. In addition, the polymer on the emulsion layer surface can be, as is well known to those skilled in the art, 0.001 to 0.25% by weight based on the total amount of polyolefin coating, of a suitable optical brightener, the total amount of polyolefin coating. In the range from 3 to 35% by weight of suitable white pigments, for example titanium dioxide, heat stabilizers, for example magnesium stearate, pigments and the like. In addition, the resin on the photographic emulsion side is
It may contain one or more pigments, for example blue, violet or magenta pigments.

A polyolefin is applied to the back of photographic paper.
If so, the polyolefin preferably has a density of 0.9
4 ~ 0.97 medium or high density polyethylene
There are many. The paper base material used in the present invention is:
Any paper that has been traditionally useful as a photographic support
It can be a base material, typically 20 g / m^Two~ 50
0 g / m ^TwoWeight range.

[0005] Polyolefins can be applied over a wide temperature range, ie, 150 ° C to 350 ° C, using a coat hanger or T
It can be extruded through a slot die into a nip formed by a metal chill load and an elastomeric pressure roll, wherein the polyolefin is forced into the slits of the porous paper and the mechanically interlocked polymer / Form a paper composite.

The coated paper is then cooled by a chill roll operating at a temperature of 4 ° C. to 32 ° C. and moved to the peeling point of the chill roll, where the paper is removed by tension and then wound on a roll or used in the next coating operation Move to the point. Prior to applying the photographic emulsion, the polymer layer on the emulsion side is pretreated by corona discharge treatment to improve the adhesion between the polymer and the emulsion.

It has been found that optical brighteners migrate from the resin over time to form invisible dust on the polymer surface. Further, when the polymer layer is subjected to corona discharge treatment, chemicals are formed and spots may be formed in the sensitized layer. Further, the density difference between the polyethylene on the emulsion side and the polyethylene on the back side causes curling of the paper.

[0008]

As a result, a process for reducing the migration of optical brighteners, improving the adhesion between the polymer and the emulsion without forming spots, and reducing the curling tendency of photographic paper. There is a need for a method.

[0009]

SUMMARY OF THE INVENTION The present invention is a method for producing a thermoplastic resin-coated photographic paper in which a thermoplastic resin on the emulsion side is subjected to frame annealing after lamination. The thermoplastic coated photographic paper is treated with its vicat softening point (vicat softening point).
The flame treatment is performed by heating the thermoplastic resin at a temperature higher than the engraving temperature. While this treatment increases the adhesion between the polymer and the emulsion, it reduces the migration of the optical brightener and also has the unexpected benefits of improved curling. The thermoplastic resin slowly cools, allowing the polymer molecules to relax, thereby reducing the amount of free volume in the polymer. The decrease in free capacity reduces the migration of the trend brightener, while increasing the density and modulus of the treated surface. This increase in modulus allows for more effective curling balance.

[0010]

DETAILED DESCRIPTION OF THE INVENTION In the manufacture of the thermoplastic coated paper for photographic paper base of the present invention, the thermoplastic is made from any coatable polyolefin material known in the art. Representative examples of these materials are:
Polyethylene, polypropylene, polystyrene, polybutylene and their copolymers. The polyolefin can be copolymerized with one or more copolymers including polyesters, such as, for example, polyethylene terephthalate, polysulfone, polyurethane, polyvinyl, polycarbonate, cellulose esters, such as, for example, cellulose acetate and cellulose propionate, and polyacrylates. Specific examples of copolymerizable monomers include vinyl stearate, vinyl acetate, acrylic acid, methyl acrylate, ethyl acrylate, acrylamide, methacrylic acid, methyl methacrylate, ethyl methacrylate, methacrylamide, butadiene, isoprene and vinyl chloride. Preferred polyolefins are film-forming and have adhesion to paper. 0.91 for the resin on the emulsion side
low density polyethylene g / cm ³ ~0.94g / cm ³ are preferred. 0.94 g / cm ^{3 to} 0.98 g / cm ³
Is most preferred for the backside layer. The polyolefin applied to the photographic emulsion side of the photographic paper may be a suitable optical brightener, for example,
arch Disclosure, Issue N. 30
8 Publication 30, December 1989
8119, paragraph V, page 998, for example, any white pigment present may be present in an amount of from 0.001 to 0.25% by weight based on the total weight of the polyolefin coating.
And most preferably 0.01 to 0.1%. Any suitable white pigment, for example, titanium dioxide, zinc oxide, zinc sulfide, zirconium dioxide, graphite, lead sulfate, lead chloride, lead aluminate, lead phthalate, antimony trioxide, white bismuth, tin oxide, tin manganese, White tungsten, and combinations thereof, can be included in the polyolefin layer. These pigments can be used in any form that is appropriately dispersed in the polyolefin. A preferred pigment is titanium dioxide in anatase crystalline form. Preferably, white pigments should be used in the range of 3-35% by weight, based on the total weight of the polyolefin coating. 5-20% titanium dioxide anatase is most preferred.

[0011] In addition to the phosphor mixture and the white pigment, the polyolefin coating may optionally contain various additives, such as antioxidants, such as 4,4'-butylidene-bis (6-tert-butyl-). Meta-cresol), di-lauryl-3,3'-thiodipropionate, N-butylated-p-aminophenol, 2,6-di-tert-butyl-p-cresol, 2,2-di-tert -Butyl-4-methylphenol, N, N-disalicylidene-
1,2-diaminopropane, tetra (2,4-tert
-Butylphenyl) -4,4'-diphenyldiphosphonite, octadecyl 3- (3 ', 5'-di-tert)
-Butyl-4'-hydroxyphenylpropionate), combinations thereof and the like; heat stabilizers such as metal salts of higher fatty acids such as magnesium stearate, calcium stearate, zinc stearate, aluminum stearate, calcium palmitate, Sodium palmitate, zirconium octylate, sodium laurate, and benzoates such as sodium benzoate, calcium benzoate, magnesium benzoate and zinc benzoate; 0.1-1.0%
Concentration (preferably 0.4-0.6% concentration) of calcium stearate. Addition of antistatic agents, lubricants, dyes, and the like are well known. Further, the emulsion side resin may comprise one or more pigments, such as the blue, violet or magenta pigments described in U.S. Pat.
It can contain barium sulfate, colloidal silica, calcium carbonate, etc., with preferred colorant combinations being 0.02-0.5% and 0.0005-0.0%, respectively.
Consisting of 5% concentration, consisting of cobalt aluminate and quinacridone, the most preferred concentrations are each 0.1 to 0.1%.
0.2% and 0.001 to 0.003%.

[0012] The paper base material used in the present invention can be any paper base material conventionally considered useful as a photographic support. The weight and thickness of the support can vary depending on the intended use. A preferred weight range is ^{20g / m 2 ~500g / m 2} , and most preferably 100 to 200 g / m ^2. The preferred thickness (thickness equivalent to commercial grade photographic paper) is 2
0 μm to 500 μm, and the most preferred thickness is 100 μm.
μm to 200 μm. It is preferable to use a paper base material that has been rolled to obtain a smooth surface. The paper base material can be made from any suitable paper stock, preferably consisting of hardwood or softwood. If necessary, bleached or unbleached pulp can be used. Paper-based materials can also be produced, in particular, from esterified cellulose fibers or from blends of wood cellulose and suitable synthetic fibers, such as blends of wood cellulose and polyethylene fibers.

As is known to those skilled in the art, the paper base material may optionally include a paper-strengthening agent such as a wet strength resin such as an amino-aldehyde or polyamide-epichlorohydrin resin, And dry strength resin,
For example, they may contain starch, for example ordinary and cationic starch, or polyacrylamide resins. In a preferred embodiment of the present invention, an amino-aldehyde or polyamide-epichlorohydrin and a polyacrylamide resin are used in combination as described in U.S. Pat. No. 3,592,731. Other conventional additives include water-soluble rubbers, such as cellulose ethers, such as carboxymethylcellulose, sizing agents such as argylketene dimer, sodium stearate, such as alum, aluminum chloride or aluminum salts. Sodium stearate, which is precipitated into a pulp fiber using a polyvalent metal salt, may be used.

Prior to the polyolefin extrusion step,
As described in U.S. Pat. No. 3,411,908, it is preferred that the paper be subjected to a corona discharge treatment to improve the adhesion of the polyolefin to the paper support.
The resin on the emulsion side is melted and then laminated on paper. Next, it peels off from a chill roll with a stripping roll. After peeling from the chill roll, the emulsion side is subjected to frame processing.
Flame throughput heats the resin above the Vicat softening temperature to fluidize the plastic. For low density polyethylene, this temperature is 99 ° C. The preferred temperature range is above 200 ° C. After flame treatment, the polymer is heated at a temperature below the Vicat softening temperature in ambient air for 0.1-10 seconds, preferably 1-10 seconds,
It must be allowed to cool without contact with the rollers.

The present invention is further described by the following examples. In the examples, the diffusion of the optical brightener was measured in the following way: the sample was incubated for 7 days in an oven at 60 ° C., and the O was able to wipe off the sample with white gloves.
By observing the amount of B (fluorescent whitening agent), quantitative measurement of the migration of the fluorescent whitening agent was performed. It was ranked from 0 (no migration) to 4 (large amount of migration).

In an embodiment, the curling is 5%, 2
ANSI at 0%, 50%, 70% and 85% humidity
It was measured using a curling test. Example 1 (control) 85.68% polyethylene with a density of 0.925 g / cc;
Anatase TiO ₂ 12.5%; ZnO 3.0%; calcium stearate 5%; 4,4′-butadiene-bis (6-tert-butylmeta-cresol) 0.1%;
And bis (benzoxazolyl) -stilbene 0.0
5% of the emulsion side resin was melted in a single screw extruder, pushed through a coat hanger die at a temperature of 316 ° C., and then laminated to a photographic grade paper support, the paper thickness being 165 μm. , Polymer layer thickness is 25μ
m. The thickness of the backside resin was 26 μm and was made of polyethylene having a density of 0.945 g / cc. After 7 days, the migration of the optical brightener is at level 4 (heavy migration) and the wet curling is -13 at 5% RH, 20% RH
-13 at 50% RH, -27 at 70% RH,
It was -44 at 85% RH. This formulation required pretreatment of corona discharge immediately prior to sensitization, and small red spots were occasionally observed.

Example 2 The same procedure was followed as in Example 1 except that the emulsion side polyethylene was flame-treated at a rate of 2.3 Joules / m ² and then allowed to cool in ambient air for 3 seconds. After one week, the migration of the optical brightener was 1 (mild, slight), and the wet curling was -9 at 5% RH and -7, 50 at 20% RH.
% RH at -9, 70% RH at -18, 85% RH at -3
It was 8. This support adhered sufficiently to the emulsion without performing the second corona discharge treatment, and no spots were observed at all after sensitization.

Example 3 A silver halide emulsion was coated on the paper of Example 2. This emulsion was chemically and spectrally sensitized as follows. Blue-sensitive emulsion (blue EM-1, U.S. Pat. No. 5,252,4)
No. 51, column 8, lines 55-68): high chloride silver halide emulsion, approximately equimolar silver nitrate and sodium chloride solutions, gelatin peptizer and thioether ripener. Precipitated by addition into a high stirring reactor containing. During silver halide grain formation for most of the precipitation, Cs ₂ Os (NO) Cl ₅ dopant was added, followed by shell formation without dopant. The resulting emulsion contained cubic grains of 0.76 μm edge size. This emulsion is optimally sensitized by the addition of a colloidal suspension of gold (II) sulfide and then heat ramped to 60 ° C.
p) heating, during which time the blue sensitizing dyes BSD-1,1-
(3-acetamidophenyl) -5-mercaptotetrazole and potassium bromide were added. Further, an iridium doping agent was added during the sensitization step.

Green-sensitive emulsion (Green EM-1): A high chloride silver halide emulsion is added to an approximately equimolar silver nitrate and sodium chloride solution in a high stirring reactor containing a gelatin peptizer and a thioether ripener. To precipitate. During silver halide grain formation for most precipitations,
Cs ₂ Os (NO) Cl ₅ doping agent was added, followed by shell formation without doping agent. An iridium doping agent was added at the final stage of particle formation. The resulting emulsion contained cubic grains of 0.30 μm edge size. The emulsion was optimally sensitized by the addition of a colloidal suspension of green sensitizing dye GSD-1, gold sulfide, heat aged and then 1- (3-acetamidophenyl) -5-mercaptotetrazole and Potassium bromide was added.

Red Sensitive Emulsion (Red EM-1): High chloride silver halide emulsion is added to a highly stirred reactor containing approximately equimolar silver nitrate and sodium chloride solutions containing a gelatin peptizer and a thioether ripener. To precipitate. The resulting emulsion contained cubic grains of 0.40 μm edge size. The emulsion was optimally sensitized by the addition of a colloidal suspension of gold (II) sulfide, then heated ramped up, and further treated with 1- (3-acetamidophenyl) -5-mercaptotetrazole, Potassium bromide and red sensitizer dye, R
SD-1 was further added. Further, an iridium doping agent was added during the sensitization step.

The coupler dispersion was emulsified by methods well known in the art, and the following layers were coated on a polyethylene resin coated photographic paper support. The photographic paper support is sized as described in U.S. Pat. No. 4,994,147, and U.S. Pat.
The pH was adjusted as described in 7,994.
The polyethylene layer coated on the emulsion side of the support,
0.1% of (4,4'-bis (5-methyl-2-benzooxazolyl) stilbene and 4,4'-bis (2-
Benzoxazolyl) stilbene, 12.5% TiO ₂
And a mixture of 3% ZnO white pigment. These layers were hardened with 1.95% bis (vinylsulfonylmethyl) ether of total gelatin weight.

Layer 1: Blue-sensitive layer Gelatin 1.530 g / m ² Blue-sensitive silver (blue EM-1) 0.280 g Ag / m ² Y-1 1.080 g / m ² Dibutyl phthalate 0.260 g / m ² 2- (2-butoxyethoxy) ethyl acetate 0.260 g / m ² 2,5-dihydroxy-5-methyl-3- (1-piperidinyl) -2-cyclopenten-1-one 0.002 g / m ² ST-16 009 g / m ² Layer 2: Intermediate layer Gelatin 0.753 g / m ² Dioctyl hydroquinone 0.094 g / Ag / m ² Dibutyl phthalate 0.282 g / m ² Disodium 4,5-dihydroxy-m-benzenedisulfonate 0.065 g ^{/ m 2 SF-1 0.002g /} m 2 layer 3: green-sensitive layer gelatin 1.270g / m ² green-sensitive silver (green EM-1) 0.263 g ^{g / m 2 M-1 0.389g} / m 2 dibutyl phthalate 0.195g / m ² 2- (2- butoxyethoxy) ethyl acetate ^{0.058g / m 2 ST-2 0.166g} / m 2 dioctyl hydroquinone 0. 039g / m ² phenyl mercaptotetrazole 0.001 g / m ² layer 4: UV intermediate layer gelatin ^{0.484g / m 2 UV-1 0.028g} / m 2 UV-2 0.159g / m 2 of dioctyl hydroquinone 0.038 g / m ² 1,4-cyclohexylene dimethylene bis (2-ethylhexanoate) 0.062 g / m ² layer 5: red-sensitive layer gelatin 1.389 g / m ² red-sensitive silver (red EM-1) 0.187 gAg / M ² C-3 0.424 g / m ² dibutyl phthalate 0.414 g / m ² UV-2 0.272 g / m ² 2- (2-butoxye Butoxy) ethyl acetate 0.035 g / m ² of dioctyl hydroquinone 0.004 g / m ² Potassium tolylthiosulfonate sulfonate 0.003 g / m ² Potassium tolyl sulphide Ne - DOO 0.0003 g / m ² Layer 6: UV Overcoat Gelatin 0.484g ^{/ m 2 UV-1 0.028g /} m 2 UV-2 0.159g / m 2 of dioctyl hydroquinone 0.038 g / m ² 1,4-cyclohexylene dimethylene bis (2-ethylhexanoate) 0.062 g / m ² layer 7: SOC gelatin 1.076 g / m ² polydimethylsiloxane 0.027 g / m ² SF-1 0.009 g / m ² SF-2 0.004 g / m ² Tergitol 15-S-5 (trademark) 0 .003g / m ² dye -1 0.018 g / m ² dye -2 0.009 g / m ² dye -3 0.0 Coated photographic paper 7 g / m ² This example was perform as expected.

Additional Embodiment 1 The photographic support according to claim 1, wherein said polyolefin is selected from the group consisting of polyethylene, polypropylene, polystyrene, polybutylene and copolymers thereof. Embodiment 2 When the polyolefin layer is made of polyester, polysulfone, polyurethane, polyvinyl, polycarbonate, cellulose ester and polyarylate (po)
A photographic support according to claim 1 which is copolymerized with a copolymer selected from the group consisting of

Embodiment 3 The photographic support according to claim 1, wherein said polyolefin layer contains a pigment. Aspect 4. The photographic support according to claim 1, wherein the polyolefin contains a fluorescent whitening agent. Aspect 5. The photographic element of claim 2, wherein said polyolefin is selected from the group consisting of polyethylene, polypropylene, polystyrene, polybutylene and copolymers thereof.

Embodiment 6 The photographic element according to claim 2, wherein said polyolefin layer is copolymerized with a copolymer selected from the group consisting of polyester, polysulfone, polyurethane, polyvinyl, polycarbonate, cellulose ester and polyarylate. Aspect 7. The photographic element of claim 2, wherein said polyolefin layer comprises a pigment. Aspect 8. The photographic element of claim 2, wherein said polyolefin comprises an optical brightener.

While the invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that variations and modifications can be effected without departing from the spirit and scope of the invention.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor William Andrew Murak New York, USA 14624, Rochester, Stoneburn Road 19

Claims (2)

[Claims] 1. A photographic support comprising: a paper base; and a polyolefin layer applied on the paper base, the polyolefin layer having been subjected to frame annealing at a temperature above the Vicat softening point of the polyolefin. . 2. A paper base; a polyolefin layer applied on the paper base, wherein the polyolefin layer has been subjected to flame annealing at a temperature higher than the Vicat softening point of the polyolefin; and a polyolefin layer applied on the polyolefin layer. A photographic element comprising at least one photosensitive layer.