JP2749399B2 - Method for producing resin-coated paper for photography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Field of the Invention The present invention relates to a resin-coated paper as a photographic support, in particular, a polyolefin resin is melt-extruded and coated on a paper substrate, and the paper end of the paper substrate is completely covered with the resin. The present invention relates to a method for producing a photographic resin-coated paper covered with a varnish.

(B) Prior Art Conventionally, resin-coated paper used as a photographic support is prepared by melting and extruding a resin on both sides of a paper substrate and applying the resin to the paper substrate as shown in FIGS. 3 and 4. Is a method of slitting a portion covered with a resin and finishing it into a roll having a fixed width.

As a prior art, Japanese Patent Application Laid-Open No. 53-110819 discloses a photographic paper in which a material capable of preventing the penetration of a developing solution is applied to a cut surface of a photographic paper coated with polyolefin. There is no description about slits in the resin coating step.

(C) Problems to be Solved by the Invention Conventionally, resin-coated paper used as a photographic support is produced by slitting a portion where a paper base is coated with a resin, so that paper dust is generated, In the step of coating the emulsion on the photographic support after slitting, there is a drawback that paper powder adheres to the surface of the photographic support or the paper roll and causes coating failure.

An object of the present invention is to provide a stable production by preventing coating failure due to paper dust in the above-described emulsion coating process.

(D) Means for Solving the Problems In the process for producing a resin-coated paper for photography of the present invention, in a step of melting and extruding a resin on both sides of a paper substrate by a tandem-type laminator, a molten resin flowing down from an extruder is applied. Apply wider than the width of the paper substrate, solidify the molten resin with a cooling roll, and then slit only the resin protruding from both ends of the paper substrate to finish the roll with a fixed width with the paper edge completely covered. It is characterized by the following.

After the molten resin is cured, the width of slitting the resin from each paper edge of the paper substrate is preferably set at an interval of 1 mm to 10 mm. If the slit width is smaller than this, it may not be possible to completely cover both ears of the paper substrate.If the slit width is wider than this, the cost increases and the handling of rolls becomes difficult due to deformation of the resin ears. Or

The cutter for slitting the resin used in the present invention is required to efficiently cut a thin resin, and a score cutter having a lower blade with a guider is preferable.

Also, the width of the resin part before slit, which is coated wider than the paper base and cooled and solidified by the cooling roll, is 3mm to 25mm
Is preferred. More preferably, it is 5 mm to 20 mm. If it is narrower than 3 mm, the resin ears shrink (neck-in) during the flow during melt extrusion coating, so the resin thickness increases only at the resin ears,
Slitting 1 mm from the paper edge of the paper substrate results in winding of the photographic resin-coated paper at the height of the ears. This is the end of the paper, and the object of the present invention is not achieved. If it is wider than 25 mm, only the resin sticks to the backup roll that presses the paper base against the cooling roll, which causes a trouble that the resin rolls around, and the amount of resin to be discarded in the slit increases, which is not economical.

In the method for producing a photographic resin-coated paper according to the present invention, the molten resin portion emerging from the paper substrate is solidified by being sandwiched between a cooling roll on one side and a backup roll on the opposite side. Therefore, the surface of the backup roll is desirably coated with Teflon, a release agent, or cooled since the molten resin adheres to the surface.

The paper substrate used in the present invention may be one containing ordinary natural pulp as a component, or synthetic pulp or synthetic fiber.

Among these, natural pulp paper containing wood pulp as a main component, which is softwood pulp, hardwood pulp, or softwood mixed pulp, is effective. Various high molecular compounds and additives can be contained in these atoms. For example, cationized starch, cationized polyacrylamide, anionized polyacrylamide, carboxy-modified polyvinyl alcohol, gelatin, etc. as a drying paper strength enhancer, fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, pigments such as petroleum resin emulsions as sizing agents As clay, kaolin, calcium carbonate, barium sulfate,
Melamine resin as wet paper strength enhancer, such as titanium oxide,
Urea resins, epoxidized polyamide resins, etc., as fixing agents, polyvalent metal salts such as aluminum sulfate and aluminum chloride, and cation-modified polymers such as cationized starch, etc.
caustic soda, sodium carbonate, hydrochloric acid, etc.
As an inorganic electrolyte, salt, bow glass, and the like, as well as a dye, a fluorescent brightener, a latex, and the like can be appropriately combined and contained. Basis weight 50 g / m ² made from the above-mentioned raw materials
Density to 200 g / m ² is the paper substrate of 0.90~1.15g / cm ³ preferably as base paper for photographic printing paper support.

The resin that covers both sides of the paper substrate includes low-density polyethylene resin, high-density polyethylene resin, polypropylene resin, polybutene resin, polyolefin resin such as polypentene resin, vinyl chloride resin, polyester resin, polycarbonate resin, and ethylene-vinyl acetate copolymer. There are coalescing resins and the like, but polyolefin resins are preferred. Particularly, polyethylene is preferable. The resin may contain white pigments such as titanium oxide and zinc oxide, fatty acid metal salts such as zinc stearate and calcium stearate, and pigments and dyes such as ultramarine blue, navy blue and phthalocyanine blue. The amount of resin coating the paper substrate is 10 g /
m ² ~40g / m ² is preferred.

Further, the photographic resin-coated paper used in the present invention may be further provided with a backing layer on the back surface according to the purpose, or a subbing layer on the front surface according to the purpose.

Photographic printing papers can be prepared by applying various silver halide photographic emulsions to the photographic resin-coated paper prepared according to the present invention. Examples of photographic emulsions include silver chloride,
Silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide,
Further, the emulsion containing the color coupler can be coated in multiple layers.

(E) Example Example 1 Based on FIG. 1 showing an example, a molten polyolefin resin 5 was coated on the back surface of a 170 g / m ² paper substrate 4 by 15 mm wider at both ends than the paper substrate width at 25 g / m ² . Is performed to cool and solidify the polyolefin resin 3 melted by the cooling roll.

Thereafter, the molten polyolefin resin 3 containing a titanium oxide pigment is applied to the front surface of the paper substrate at 23 g / m ² as in the case of the back surface.

At this time, the coating width is 10 mm wider at each end than the width of the paper base, and the molten resin is solidified by a cooling roll. Then, a score cutter consisting of an upper blade 1 and a lower blade 2 slits 3 mm from both ends of the paper base. And finish as a roll. A color emulsion is applied to this roll at a coating speed of 200 m / min.
After continuous application for days, no application failure due to paper dust adhering to a paper roll or the like was observed.

Example 2 Based on FIG. 2 showing an example, a paper substrate 4 of 170 g / m ² was used.
The melted polyolefin resin 5 is applied to the back side of the paper at a rate of 25 g / m ² , which is 15 mm wider at both ends than the paper substrate width, and the molten polyolefin resin is cured by a cooling roll. After that, the polyolefin resin 3 melted on the front surface of the paper
g / m ² coating. At this time, the application width is 10 mm at both ends from the paper base width.
After applying the coating widely and curing the molten resin with a cooling roll, a 3 mm portion from both ends of the paper base is slit with a shear cutter comprising an upper blade 1 and a lower blade 2.

In this case, the shear cutter lower blade 2 with the guider 6 is used. After that, it is finished as a roll. Apply a monochrome emulsion to this roll at a coating speed of 100 m / min.
After continuous application for days, no application failure due to paper dust adhering to a paper roll or the like was observed.

Example 3 Table 1 also shows the results obtained in the same manner as in Example 2 except for the conditions described in Table 1.

Comparative Example 1 In accordance with FIG. 4 which is a conventional method, a portion where a paper substrate was present was slit and a roll of a photographic support was produced according to Example 1 under the other conditions. Further, as a result of applying the emulsion to the roll, a problem in which foreign matter of paper powder adhered to the emulsion layer and a problem in which paper powder adhered to both ends of the paper roll occurred after continuous application for two days.

(F) Effect of the Invention By completely covering the edge of the paper substrate with the resin, it is possible to completely prevent paper dust generated from the paper substrate in the emulsion coating process and greatly reduce emulsion coating failure. Become.

[Brief description of the drawings]

FIG. 1 is a schematic view in which a resin portion protruding from both ends of a paper base by a score cutter method described in Example 1 is slit and edge-sealed. FIG. 2 is a schematic view in which a resin portion protruding from both ends of a paper base by a shear cutter method having a guider on a lower blade portion described in Example 2 is slit and edge-sealed. FIG. 3 and FIG. 4 show the conventional slitting method at the end of the photographic resin-coated paper. 1 Upper blade 2 Lower blade 3 Front resin layer 4 Paper substrate 5 Back resin layer 6 Guider

Claims (3)

(57) [Claims] In the step of melting and extruding a resin on both sides of a paper substrate by a tandem type laminator, a molten resin flowing down from an extruder is applied wider than a width of the paper substrate, and the molten resin is solidified by a cooling roll. And thereafter, slitting only the resin protruding from both ends of the paper substrate to completely cover the end of the paper. 2. The method for producing a resin-coated paper for photographic use according to claim 1, wherein when slitting only the resin, portions of 1 to 10 mm from both ends of the paper substrate are slit. 3. The method for producing a photographic resin-coated paper according to claim 1, wherein the method of slitting only the resin is performed by a score cutter or a shear cutter with a guider on the lower blade.