JPH0627585A - Substrate for photographic printing paper - Google Patents

Abstract

PURPOSE:To provide a substrate for photographic printing paper having high rigidity and excellent adhesion of the coating layer to the base paper. CONSTITUTION:When the surface of base paper to be coated with an emulsion is coated with plural polyester-based resin layers or plural layers of a compsn. prepd. by mixing and dispersing a pigment in polyester-based resin to obtain a substrate 1 for photographic printing paper, the resin of the coating layer 2 adjacent to the surface of the base paper to be coated with an emulsion is composed of 85-0wt.% polyester and 15-100wt.% polyolefin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing paper support, and more particularly to a photographic printing paper support having high rigidity and excellent adhesion of a coating layer to a base paper.

[0002]

2. Description of the Related Art Conventionally, in photographic printing paper, in order to improve water resistance and light reflection efficiency, the surface of the base paper on which the emulsion is coated is coated with a polyolefin layer containing a white pigment such as titanium oxide mixed and dispersed therein. Is being done. Also,
It is common practice to provide a polyolefin layer on the back side of the base paper on the emulsion coating side for water resistance. Polyolefins have been widely used because of their excellent flexibility and processability. In recent years, in order to obtain high resolution and more excellent flatness, it has been studied to use polyester instead of conventional polyolefin as a resin for coating the surface of the raw paper (Japanese Patent Application No. 3-89983).

[0003]

However, while the polyester resin is hard and strong, there is a problem that even if an attempt is made to apply it to the surface of the base paper by the melt extrusion laminating method, it will be hardened immediately due to its high melting point and will not adhere easily.

Therefore, an object of the present invention is to obtain a support for photographic printing paper which has a high rigidity and an excellent adhesion of the coating layer to the base paper.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned need for improvement, the present inventors have found that a polyester-based resin layer or a polyester-based resin is formed on the emulsion-coated surface of the base paper. In a photographic printing paper support coated with a plurality of composition layers in which pigments are mixed and dispersed, of the coating layers, the resin composition of the layer laminated adjacent to the emulsion coating side surface of the base paper is polyester / polyolefin (weight: Ratio) = 85/15 to 0/100, in particular, of the coating layers, the thickness of the layer laminated adjacent to the emulsion coating side surface of the base paper is 1/2 or less of the thickness of all the coating layers. It was found that a support for photographic printing paper having high rigidity and excellent adhesion of the coating layer to the base paper can be obtained by adjusting the thickness to be 1 μm to 25 μm, and the present invention has been completed.

Polyesters include polycondensates of aromatic dicarboxylic acids such as polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalene dicarboxylic acid ester and aliphatic diols, and bisphenol A and 5-sodium sulfoisophthalic acid. Examples thereof include copolymers into which copolymer components such as Of these, polyethylene terephthalate is particularly preferable, and the effect of increasing the rigidity is easily obtained.

As polyethylene terephthalate, in addition to polyethylene terephthalate alone, a mixture of polyethylene terephthalate and another polyester blended at a ratio of 50% by weight or less, or, for example, isophthalic acid as a dibasic component other than terephthalic acid is used. As a glycol component other than ethylene glycol, one or more components selected from neopentyl glycol, triethylene glycol, butanediol, ethylene oxide adduct of bisphenol A, etc. are used,
It also includes a copolymer obtained by copolymerizing the polyethylene terephthalate component as the main component. The molecular weight of these polymers is preferably 30,000 to 50,000.

Among the coating layers, polyolefins forming a layer adjacent to the emulsion coating side surface of the base paper are, for example, polyethylene, polypropylene, ethylene-
Propylene copolymer, ethylene-vinyl acetate copolymer,
Examples include polystyrene and vinyl copolymers, polyester / polyolefin (wt%) = 85/15 to 0/1
The mixing ratio is 00, preferably 80/20 to 0/100. If the amount of the polyolefin is less than 15% by weight, the adhesion to the emulsion-coated surface of the base paper will not be improved. Further, the content of the polyolefin may be 100% by weight, but in that case, if the film thickness of the layer is not made as thin as possible, there arises a problem that the rigidity is lowered.

A pigment may be added to the coating layer in the present invention. As the pigment, powders of titanium dioxide, barium sulfate, zinc oxide, talc, calcium carbonate, aluminum oxide, silicon oxide and the like, solid solutions of these and the like can also be used. The particle size of the pigment is 0.04 to 1 μm
Is usually used. When it is 0.04 μm or more, it is difficult to uniformly mix and disperse the pigment in the resin, which is not preferable. If it is 1 μm or more, the surface of the coating film of the composition becomes too rough and the quality of the photograph is deteriorated. Among the pigments, titanium dioxide and barium sulfate are preferable, and in these cases, particularly preferable average particle diameter is 0.1 to 0.8 μm.

Titanium dioxide may be either anatase type or rutile type, but anatase type titanium dioxide is preferred when whiteness is prioritized, and rutile type titanium dioxide is preferred when sharpness is prioritized. Specific product names include KA-10 and KA-20 manufactured by Titanium Industry.
Titanium dioxide is kneaded into the resin with a kneading machine such as a two-roll, three-roll, kneader or Banbury mixer together with a dispersing aid such as a metal salt of higher fatty acid, higher fatty acid ethyl, higher fatty acid amide, or higher fatty acid. An antioxidant may be contained in the resin layer, and the content may be 50 ppm to 1000 ppm with respect to the resin.

The coating layer on the emulsion coating side surface of the base paper may be two layers or three layers, but if a concentration gradient is provided such that the pigment content concentration in the coating layer is low in the resin layer on the base paper side and high in the outermost layer. Good. The outermost layer of the coating layer farthest from the emulsion-coated surface is an important layer that determines the resolution of the photograph, and the highest pigment concentration increases the resolution of the photograph. The pigment concentration in the outermost layer is 10% by weight or more, preferably 15% by weight or more,
If it exceeds 50% by weight, cracking occurs, which is not practical. Layers other than the outermost layer preferably contain a small amount of pigment, and the content is 10% by weight or less, preferably 7% by weight.
It is less than or equal to weight%.

The total thickness of the resin / pigment composition coated on the emulsion-coated side of the base paper is preferably 12 to 50 μm, more preferably 18 to 35 μm. If the thickness exceeds this range, the brittleness of the resin will be emphasized, causing physical problems such as cracking. If the thickness falls below this range, the original waterproof property of the coating will be impaired and the physical properties will be soft. It is not preferable because it becomes too much.

Of the coating layers on the emulsion coating side of the base paper, the layer thickness adjacent to the emulsion coating side surface of the base paper is 1/2 or less of the thickness of all the coating layers and is 1 μm. ~ 25μ
m, preferably ⅓ or less of the film thickness of all coating layers,
And it is good to set it as 1 micrometer-15 micrometers. When the film thickness exceeds 25 μm, the effect of increasing the rigidity in the present invention is hard to occur. The thickness of each coating layer other than the layer laminated adjacent to the emulsion-coated side surface of the base paper is preferably 5 μm to 20 μm.

The resin contained in the coating composition (back coat layer) on the back surface of the base paper (the side opposite to the side on which the photosensitive emulsion is coated) can be widely used as long as it is a resin that can be extrusion-molded and solvent-soluble. it can. For example, polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polypropylene and polystyrene, polyamide resins, polyvinyl alcohol, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylonitrile resin,
Examples thereof include poly (meth) acrylic acid esters, epoxy resins, polyether ketones and the like. Further, in applying the backcoat layer, when the resin composition of the layer laminated adjacent to the back surface of the base paper is a resin layer mainly composed of polyester, the resin composition in the layer adjacent to the emulsion coating side surface of the base paper, That is, it goes without saying that if the composition is the same as polyester / polyolefin (weight ratio) = 85/15 to 0/100, the adhesiveness can be similarly improved.

This back coat layer is provided for the purpose of preventing static charge, curling, etc., and is disclosed in Japanese Examined Patent Publication No. 52-18020.
JP-B-57-9059, JP-B-57-53940,
JP-B-58-56859, JP-A-59-214849
No. 5, JP-A-58-184144 and the like, or an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant and the like, which are described or exemplified, are appropriately combined and contained. You can

The thickness of the back coat layer is preferably 5 to 50 μm, more preferably 15 to 30 μm. If the thickness exceeds this range, the brittleness of the resin will be emphasized, causing problems such as cracking in physical properties. If it is less than this range, the waterproof property which is the original purpose of the coating is impaired and the physical properties become too soft, which is not preferable.

As a method for producing the emulsion coating side coating layer and the back layer of the base paper, there is a melt extrusion lamination method.

As the base paper, a natural pulp paper containing normal natural pulp as a main component, a mixed paper consisting of natural pulp and synthetic fibers, a synthetic fiber paper containing synthetic fibers as a main component, a synthetic resin film such as polystyrene or polypropylene. Any of the so-called synthetic papers obtained by converting the above into a pseudo paper may be used, but natural pulp paper is particularly preferably and advantageously used as the substrate of the support for photographic printing paper. As additive chemicals, in addition to alkyl ketene dimer, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, higher fatty acid salt, paraffin wax, sizing agents such as alkenyl succinic acid, paper strengthening agents such as polyacrylamide The one to which a fixing agent such as sulfuric acid band is added is used. In addition, dye,
A fluorescent dye, a slime control agent, an antifoaming agent, etc. are added. Further, a softening agent is added if necessary.

The surface of the pulp may be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, and modified products of polyvinyl alcohol. In this case, as the polyvinyl alcohol modified product,
Examples thereof include carboxyl group-modified products, silanol-modified products and copolymers with acrylamide. The amount of the film-forming polymer applied when the surface is sized with the film-forming polymer is 0.1 g / m ^{2 to} 5.0 g / m ² , preferably 0.5 g / m ^{2 to} 2.0 g / m ^2. Adjusted to.
Further, an antistatic agent, a fluorescent whitening agent, a pigment, an antifoaming agent and the like can be added to the film forming polymer at this time, if necessary.

The base paper is prepared by using a pulp machine containing a pulp machine containing a filler, a sizing agent, a paper-strengthening agent, a fixing agent, and the like, which are added as necessary, as described above, with a paper machine such as a Fourdrinier paper machine. Manufactured by paper making, drying and winding. The surface size treatment is performed before or after the drying, and the calender treatment is performed between the drying and the winding. When the surface sizing treatment is performed after drying, this calendering treatment can be carried out either before or after the surface sizing treatment, but it is preferable to carry out the calendering treatment in the final finishing step after various treatments have been carried out. . In the calendering process, known metal rolls and elastic rolls that are commonly used in the production of paper are used. The base paper is calendered as described above and finally adjusted to a film thickness of 50 μm to 250 μm. The density of the base paper ^{0.8g / cm 3 ~1.3g / cm 3} , preferably from ^{1.0g / cm 3 ~1.2g / cm 3} .

As a support for photographic photographic paper, various photographic constituent layers are coated, for color photographic photographic paper, for black-and-white photographic photographic paper, for typesetting photographic paper, for photographic photographic paper, for reverse photographic materials,
Silver salt diffusion transfer method Used for various purposes such as negative and positive printing, printing materials, etc., provided with silver chloride, silver bromide, silver chlorobromide, silver iodobromide, and silver chloroiodobromide emulsion layers. The silver halide photographic emulsion layer contains a color coupler,
It is considered as a multilayer silver halide color photographic constituent layer. Further, a silver salt diffusion transfer image receiving layer containing a physical phenomenon nucleus is provided.

[0022]

The photographic printing paper support of the present invention is a photographic printing paper support having high rigidity and excellent adhesion of the coating layer to the base paper.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0024]

EXAMPLE A resin having the composition of the lower layer shown in Table 1 was melt-extruded at 300 ° C. on the surface of a base paper having a thickness of 150 μm, and 10
A coating layer having a thickness of μm was formed.

Next, titanium dioxide (particle size: 0.
3 μm) was mixed at a ratio of 10 parts by weight and melt extruded at 300 ° C. to form a coating layer having a thickness of 20 μm.

Polyethylene terephthalate was melt extruded at 300 ° C. on the back surface to form a coating layer having a thickness of 30 μm.

The resulting photographic printing paper support was evaluated for the adhesion of the coating layer on the emulsion coating side to the base paper and the rigidity of the photographic printing paper support by the following methods.

(1) Adhesion As shown in FIG. 1, a photographic printing paper support 1 having a width of 1.5 cm was cut out, and the 180 ° peel strength of the coating layer 2 was pulled by a tensile tester Strograph (Toyo Seiki Seisakusho Co., Ltd.). )).

(2) Rigidity As shown in FIG. 2, a photographic printing paper support 1 having a width of 1.5 cm is fixed to a fixing jig 3 while leaving 1.0 cm above the photographic printing paper support. 4mm on top of the support
The force applied when moved was measured. The results are shown in Table 1.

Table 1 shows the above measurement results. In the table,
PE represents polyethylene and PET represents polyethylene terephthalate.

[0031]

[Table 1]

As can be seen from the table, the photographic printing paper support of the present invention is superior in the adhesiveness of the coating layer to the photographic printing paper support of the comparative example, and the rigidity is maintained at the same level. I understand that

[Brief description of drawings]

FIG. 1 is a diagram showing a method for measuring the adhesion of a coating layer to a base paper in a photographic printing paper support.

FIG. 2 is a schematic view of a stiffness measuring device for a support for photographic printing paper, (a) is a side view, and (b) is a front view.

[Explanation of symbols]

Reference numeral 1 is a photographic printing paper support, 2 is a coating layer, and 3 is a fixing jig.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display part D21H 27/00

Claims (2)

[Claims] 1. A support for photographic printing paper, comprising a base paper coated with a plurality of layers of a resin layer containing polyester as a main component or a composition layer containing a polyester containing resin as a main component and a pigment dispersed on the emulsion-coated surface of the base paper. Of the layers, the resin composition of the layer laminated adjacent to the emulsion-coated surface of the base paper is polyester / polyolefin (wt%) = 85/15 to 0/1.
A support for photographic printing paper, characterized in that 2. The thickness of a layer laminated adjacent to the surface of the base paper on which the emulsion is coated is 1/2 of the thickness of all the coating layers.
The photographic printing support according to claim 1, which is not more than 1 μm to 25 μm.