JP2602077B2 - Photographic paper support for panel photography - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photographic printing paper support, and more particularly, to a photographic printing paper support suitable for attaching to a panel.

<< Prior Art >> In recent years, for the purpose of rapid development of photographic printing paper, a water-resistant photographic printing paper support in which both surfaces of the paper are coated with a polyolefin such as polyethylene has been put to practical use. Among them, glossy photographic printing paper having a smooth surface, that is, a polyolefin coating layer on the side to which a photographic emulsion is applied, is preferably used.

In addition, various film-forming polymers are applied to the surface of the base paper for surface sizing such as increasing the surface strength of the base paper as the base material of the polyolefin-coated water-resistant support. As a polymer, for example, when starch is used, punctate blisters easily occur due to delamination of the base paper surface during polyolefin extrusion coating,
In addition, polyvinyl alcohol having excellent film-forming properties and modified products thereof are often used, for example, because a photographic printing paper excellent in the amount of stain of the developing solution from the cut section during development processing cannot be obtained. It is also known that when polyvinyl alcohol or a modified product thereof is used, a photographic printing paper support having excellent surface sizing performance and excellent gloss and smoothness can be obtained.

<< Problems to be solved by the invention >> After applying polyvinyl alcohol or a modified product thereof on both sides of the base paper, a polyolefin coating layer is laminated thereon,
Photographic paper obtained by applying a photographic emulsion to the surface of a photographic paper support with a white pigment contained in the polyolefin coating layer on the front surface has excellent surface sizing performance and is finished by rapid development processing. It is suitable for obtaining good photos. However, when a photograph obtained using such a photographic paper is pasted on a panel, when glued to the back surface of the photographic paper and adhered to a panel board, glue adhesion to the polyolefin coating layer is poor. However, there is a problem that peeling occurs immediately after application or over time. Therefore, it has been conventionally performed to peel off the polyolefin coating layer on the back surface, glue it to the exposed base paper and stick it to the panel board.In this case, the polyolefin coating layer is difficult to peel off, When peeling, the base paper is torn and the exposed surface of the base paper becomes uneven, and when this surface is glued with water and glued to a panel board, a pattern-like shadow along the unevenness of the base paper occurs on the photographic surface. There was a problem that a problem occurred and a good panel could not be obtained.

The present inventors have conducted intensive studies to solve the conventional drawbacks, and as a result, by adjusting the amount of polyvinyl alcohol or a denatured product thereof applied to the back side of the base paper, the peeling of the polyolefin coating layer on the back side was performed on a panel board. The present inventors have found that the present invention can be carried out conveniently, and arrived at the present invention.

Accordingly, it is an object of the present invention to provide a photographic printing paper support which enables favorable panel photograph production.

<< Means for Solving the Problems >> The object of the present invention is to provide a base paper in which polyvinyl alcohol or a modified product thereof is applied on both sides, a polyolefin coating layer is further laminated thereon, and the polyolefin coating on the front side is performed. In a photographic printing paper support in which the layer contains a white pigment, the amount of the polyvinyl alcohol or a modified product thereof applied to the front surface of the base paper is larger than the amount of application to the back surface of the base paper, and the base paper The coating amount of the polyvinyl alcohol or a modified product thereof on the back surface is
The object was achieved by a support for a photographic printing paper for a panel photograph, which is characterized by being 0.4 g / m ² or less, wherein the base paper surface exposed by peeling off the polyolefin coating layer on the back of the photograph is attached to a panel board.

 Hereinafter, the present invention will be described in more detail.

The base paper used for the photographic printing paper support according to the present invention is selected from materials generally used for photographic printing paper. That is, natural pulp selected from conifers, hardwoods, etc. is used as a main raw material, and if necessary, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, alkyl ketene dimer, higher fatty acids, paraffin wax, alkenyl succinic acid, etc. To which a sizing agent, a paper strength enhancer such as polyacrylamide, and a fixing agent such as a sulfate band and a cationic polymer are added. Further, synthetic pulp may be used in place of the above natural pulp, or natural pulp and synthetic pulp may be mixed in an arbitrary ratio.

As the support for photographic printing paper of the present invention, a base paper in which polyvinyl alcohol or a modified product thereof is applied to both sides of a base paper is used. Examples of the modified polyvinyl alcohol in this case include carboxyl group-modified products, silanol-modified products, and copolymers with acrylamide.

Photographic paper support of the present invention, the coating amount of polyvinyl alcohol or a modified product thereof on the back of the base paper 0.4 g / m ² or less,
Preferably, it is an ^{0.05g / m 2 ~0.3g / m 2} .

<< Action >> When the amount of the polyvinyl alcohol or a modified product thereof applied to the back side of the base paper is less than 0.05 g / m ² , there is a problem that a large amount of developer stains from the cut cross section during the development processing. If it is not preferable, and if it exceeds 0.4 g / m ² , the above-described problem occurs, and a good panel cannot be obtained, and the object of the present invention cannot be achieved.

On the other hand, when the coating amount of the polyvinyl alcohol or the modified product thereof is in the range of the present invention, the action thereof and the amount of the base paper pulp are small in contact with the polyvinyl alcohol or the modified product thereof. The polyolefin coating layer on the back side of the support can be easily peeled off, and the polyolefin coating layer is peeled off with polyvinyl alcohol or a modified product thereof and a small amount of base paper pulp on the base paper surface which is acted on by the polyvinyl alcohol. Therefore, on the back surface of the photographic printing paper support, there is no unevenness that impairs the aesthetics of the photograph after panel production, and since the pulp fibers of the base paper are exposed, the water and glue paste are also good, By peeling and gluing the polyolefin coating layer on the back surface, favorable panel production becomes possible.

Here, with respect to the coating amount of polyvinyl alcohol or a modified product thereof applied to both sides of the base paper, when the coating amount on the front surface is substantially equal to or less than the coating amount on the back surface,
The effect of improving strength between base paper layers close to the base paper surface is reduced,
During extrusion coating with polyolefin, dot-like blisters occur due to delamination of the surface of the base paper, the smoothness of the surface of the water-resistant support is reduced, and there is a problem that the commercial value as a glossy photographic paper is lost. To avoid such inconvenience,
It is preferable that the ratio of the amount of coating on the front side / the amount of coating on the back side is 1.5 / 1 or more, so that unevenness suitable for producing a panel with glossy surface printing paper having excellent smoothness can be obtained. It is possible to more reliably form the back surface with a small amount of water and glue.

Polyvinyl alcohol or a modified product thereof is dissolved in water or one or two mixed solvents selected from solvents such as alcohols such as methanol and ethanol, and further, if necessary, an antistatic agent and a fluorescent brightener , A solution obtained by adding a pigment, an antifoaming agent and the like are sequentially or simultaneously applied to both sides of the base paper by various application methods such as a surface size press, a gate roller, a blade coater, a bar coater, a plate size press, and a spray. I can do it.

The application amount of polyvinyl alcohol or a modified product thereof can be changed depending on the ratio of the solvent in the solution containing the same, the solution viscosity, the application conditions such as the nip pressure at the time of application, and the like.

Further, the base paper is made from a pulp slurry containing the above-mentioned pulp and additives such as fillers, sizing agents, paper strength agents, fixing agents and the like added as required by a paper machine such as a fourdrinier paper machine, and dried. It is manufactured by winding. Before or after this drying, the coating and drying of the polyvinyl alcohol or a modified product thereof is performed, and a calendering process is performed during winding after drying, and finally a basis weight of 80 to 200 g / m ² ,
The thickness is adjusted to 80 to 230 μm.

The support for photographic printing paper of the present invention comprises a base paper coated with a polyolefin on both sides, and a white pigment on the front side, that is, the polyolefin coating layer on the side to which the photographic emulsion is applied.

Examples of the polyolefin resin include α-olefin homopolymers such as polyethylene and polypropylene, and mixtures of these various polymers.
Particularly preferred polyolefins are high density polyethylene,
Low-density polyethylene and mixtures thereof. There is no particular restriction on the molecular weight of these polyolefins as long as they can be extrusion-coated, but usually polyolefins having a molecular weight in the range of 20,000 to 200,000 are used.

The thickness of the polyolefin coating layer is not particularly limited, and can be determined according to the thickness of a conventional polyolefin coating layer for a photographic paper support, and is preferably 15 to 50 μm.

The front surface, that is, the polyolefin coating layer on the side to which the photographic emulsion is applied contains a white pigment. The type and amount of the white pigment are, for example, 5 to 20% by weight of titanium oxide pigment. It is appropriately selected from known techniques and employed, and it is also possible to add known additives such as a fluorescent whitening agent and an antioxidant. In addition, the polyolefin coating layer on the back surface may be composed of only the polyolefin resin, and may have a configuration in which a coloring pigment or a white pigment, and the same additives as the polyolefin coating layer on the front surface are further added. Can also.

In addition, as the extrusion coating equipment when extrusion-coating a polyolefin, a usual polyolefin extruder and a laminator are used.

<< Effects of the Invention >> As described above in detail, according to the present invention, the backside polyolefin coating layer can be easily peeled off from the photographic printing paper, and when the backside polyolefin coating layer is peeled off, the base paper Since the polyolefin coating layer can be peeled off with a small amount of the base paper layer on the back surface, there is no unevenness that impairs the aesthetic appearance of the photograph after panel production. Also, since the pulp fiber of the base paper is exposed, water and glue are good.
It is possible to provide a photographic printing paper support suitable for attaching a photographic panel. Therefore, it is possible to produce a favorable photographic panel by peeling off the polyolefin coating layer on the back surface and applying water and gluing.

Hereinafter, the present invention will be described in more detail by examples,
The present invention is not limited by these examples.

[Examples 1 to 3, Comparative Example 1] Wood pulp composed of 80% LBKP and 20% LBSP was beaten using a disc refiner, adjusted to a Canadian freeness of 250 cc, and then sodium stearate was added to the pulp slurry. Anionic polyacrylamide,
And aluminum sulphate 1.
5%, 0.5%, 1.0% added, paper making with Fourdrinier paper machine, drying,
Calendar processing was performed. The base paper was formed at a basis weight of 170 g / m ² to obtain a base paper having a thickness of 165 μm.

In the middle of the paper machine drying zone, PVA is applied to both sides of the base paper.
-110 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was dissolved in water and applied by a surface size press and a gate roller so as to have a dry weight shown in Table 1 respectively.

The amount of the polyvinyl alcohol to be applied is calculated by extracting the polyvinyl alcohol layer formed on one surface of each with the same conditions, extracting with hot water, formalizing with formaldehyde, and measuring the dry weight of the obtained precipitate. I asked for it.

Thereafter, the base paper was run at 50 m / min, and a high-density polyethylene (density) was applied to the back of the base paper using a melt extruder.
0.960 g / cm ³ , MI = 13 g / 10 min) was applied by melt extrusion to a resin thickness of 30 μm to form a resin layer composed of a mat surface.

Next, a low-density polyethylene containing 10% by weight of titanium dioxide (density 0.923 g / c
m ³ , MI = 7 g / 10 min) was melt-extruded to a resin thickness of 30 μm to form a resin layer having a glossy surface, and the photographic printing paper supports of Examples 1 to 3 and Comparative Example 1 were produced.

Using each of the obtained photographic printing paper supports, ordinary gelatin and a silver halide photographic emulsion were coated, exposed and developed to produce photographic paper, and the glossy surface and the smoothness of the screen of the photographic printing paper were prepared. Was visually evaluated. Further, the polyolefin coating layer on the back of the photographic printing paper is peeled off, the degree of peeling, the peel strength, and the thickness change of the base paper back layer which is peeled off by being adhered to the back polyolefin coating layer at the time of peeling are measured, and the photographic printing paper is paneled. The unevenness of the surface was observed as the appearance of the panel photograph after being attached to the board.

As a result, differences were observed in the smoothness of the glossy surface photographic printing paper, the peelability of the back polyolefin coating layer at the time of producing the panel photograph, and the appearance of the panel photograph, and the results are also shown in Table 1.

The evaluation of the releasability in Table 1 was performed according to the following evaluation criteria.

・ ・ ・: The polyolefin coating layer on the back surface can always be peeled off with good releasability with a slight amount of base paper adhered.

Δ: The polyolefin coating layer on the back surface may or may not be peeled off with a slight amount of base paper adhered.

X: It is difficult to peel the polyolefin coating layer on the back surface with a slight amount of base paper adhered, and a strong force is required when peeling.

The appearance of the panel photograph was evaluated according to the following evaluation criteria.

・ ・ ・: The photographic surface of the panel is smooth and beautiful without unevenness due to peeling of the back surface.

Δ: Although there are some irregularities due to the peeling of the back surface in the panel photograph, it is unobtrusive and acceptable when observed from a distance.

×: Unevenness of the panel photograph due to peeling of the back surface is conspicuous even at a distance, and the appearance is inferior and has no commercial value

Furthermore, the evaluation of the smoothness of the glossy surface photographic printing paper was performed according to the following evaluation criteria.

・ ・ ・: The surface has shallow fine irregularities and a smooth surface shape close to a mirror surface.

Δ: The surface has a deep matte surface, and its commercial value is low as glossy photographic paper.

Claims (2)

(57) [Claims] 1. A photographic printing paper support comprising a base paper, on which polyvinyl alcohol or a modified product thereof is applied on both sides thereof, a polyolefin coating layer laminated thereon, and the front polyolefin coating layer containing a white pigment. The coating amount of the polyvinyl alcohol or a modified product thereof on the front side of the base paper is larger than the coating amount on the back side thereof, and
The coating amount of the polyvinyl alcohol or a modified product thereof on the back side of the base paper is 0.4 g / m ² or less,
A support for a photographic paper for a panel photograph, wherein the base paper surface exposed by peeling off the polyolefin coating layer on the back of the photograph is attached to a panel board. 2. The support for photographic printing paper for panel photographs according to claim 1, wherein the ratio of the amount of front side coating / the amount of back side coating of polyvinyl alcohol or a modified product thereof is 1.5 / 1 or more.