JPH0750315B2 - Support for photographic paper - Google Patents

Description

The present invention relates to a support for photographic printing paper, and more specifically,
The present invention relates to a photographic printing paper support having a polyolefin resin coating layer on both sides of a pulp-based base paper.

<< Prior Art >> A photographic printing paper is printed and liquid-developed in a photo lab or the like. Although pulp is used as a raw material for the base paper of the photographic paper, a polyolefin resin coating layer or the like is provided on both sides of the base paper from the viewpoint of waterproofness. Further, the photographic printing paper is usually in a roll shape, and after being printed and developed, it is cut into a predetermined size.

<< Problems to be Solved by the Invention >> However, the conventional roll-shaped photographic printing paper has a lack of appearance in which a large amount of pulp fibers are exposed at the cut end after cutting, and in this case, the beauty as a photograph is impaired. And
There was a problem that its value decreased. Further, as a method for improving this, conventionally, a method of increasing the amount of the strengthening agent with respect to the sizing agent in the web by 1.8 times or more, or pulp from fibers having a specific length or less in the base paper of the support for photographic printing paper is used. Although a method of use (Japanese Patent Publication No. 56-54628) has been proposed, it is not always effective as a method of improving the appearance of the cut end of roll-shaped photographic printing paper. If there are many, there is a problem such as a cost disadvantage.

Therefore, the object of the present invention is to have good sharpness when cutting a roll-shaped photographic printing paper, and the appearance of the cut end is good with almost no pulp fiber being exposed at the cut end,
An object of the present invention is to provide a support for photographic printing paper that can be manufactured at low cost.

<< Means for Solving the Problem >> The above object of the present invention is to provide a photographic paper support having a polyolefin resin coating layer on both sides of a base paper made of pulp, in which the pulp used as the base paper has zero-distance tensile strength. Achieved by a photographic paper support characterized in that the pulp has a relationship (Z-T) ≤ 8 kg between thickness (Z) and tensile strength (T).

The zero-distance tensile strength of pulp as used herein refers to that measured by the following method.

That is, the pulp to be used is JIS P-8210 according to the method using the beater of "Pulp strength test method for papermaking" JIS P
-Refine up to 250 ml according to the Canadian standard form of "8211" Pulp freeness test method ". Then the beaten pulp is
Prepare a handmade paper of 175 g / m ² using a handmade machine according to P-8209 “Handmade paper preparation method for pulp test”, then squeeze the water content of this handmade paper with a hand press and dry it with a drum dryer. By drying at a temperature of 120 ° C.

This handmade paper is 175μ thick using a machine calendar.
Prepared in accordance with JIS P-8111 "Pretreatment of test paper" and measured the tensile strength at the gripping interval of 50 mm according to JIS P-8113 "Tensile strength test method of paper and board". Further, the zero distance tensile strength is measured according to Tappi standard T-481 "Zero distance tensile strength".

The zero distance tensile strength measured by the above method represents the single fiber strength of pulp, and the tensile strength represents the interfiber bonding strength. The sharpness of photographic paper depends on whether the pulp fibers in the base paper are easily exposed during cutting.The exposure of the pulp fibers depends on the single fiber strength of the pulp expressed by the zero distance tensile strength and the tensile strength. It is determined by the relative relationship between the pulp fibers and the interfiber binding force between them. That is, the higher the single fiber strength and the weaker the interfiber bonding strength, the poorer the breakage phase. Conversely, the weaker the single fiber strength and the stronger the inter-fiber bonding force, in other words, the smaller the zero-distance tensile strength (Z) and the greater the tensile strength (T), that is, (Z-T). The smaller the value, the better the sharpness.

For the base paper of the photographic printing paper support of the present invention, pulp having a (ZT) value of 8 kg or less, preferably 6 kg or less is used, and the freeness of the pulp is 200 to 350 ml (Canadian standard type). It is preferable.

Therefore, the pulp used for the base paper of the support for photographic printing paper of the present invention is not particularly limited as long as it satisfies the relationship between the zero distance tensile strength and the tensile strength, and various pulps can be used. . For example, it is also possible to use LBKP alone, as will be apparent from the examples described below.
One or two or more of P, LBSP, NBKP and the like can be used in an appropriate mixture.

In addition, clay, talc, calcium carbonate,
Needs fillers such as urea resin particles, loin, alkyl ketene dimer, higher fatty acid salts, paraffin wax, sizing agents such as alkenyl succinic acid, paper strengthening agents such as polyacrylamide, fixing agents such as sulfuric acid bands, cationic polymers, etc. It can be added accordingly. Further, the surface of the pulp can be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, and a modified product of polyvinyl alcohol. Examples of the polyvinyl alcohol-modified product in this case include a carboxyl-modified product, a silanol-modified product, and a copolymer with acrylamide. The coating amount of the film-forming polymer when surface sizing with the film-forming polymer is 0.1 to 5.0 g /
It is adjusted to m ² , preferably 0.5 to 2.0 g / m ² . Further, the film-forming polymer at this time, if necessary, an antistatic agent,
Fluorescent brighteners, pigments, defoamers and the like can be added.
The base paper used for the photographic support of the present invention is usually composed of the above-mentioned pulp, additives, surface treatment agents, etc.
The thickness is adjusted to 80 g / m ^{2 to} 200 g / m ² and the thickness is 80 μ to 230 μ.

For the polyolefin resin coating layer laminated on both sides of the base paper, for example, a polyethylene layer having a thickness of 15 μ to 40 μ can be used. The polyolefin resin film layer on the side on which the photographic emulsion layer is formed contains 5 to 20% by weight of titanium oxide.

<< Effects of the Invention >> As described in detail above, the photographic printing paper support of the present invention can improve the appearance of the cut end after cutting by simply selecting the characteristic value of the pulp used for the base paper. It is cheap.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Incidentally, in this example, the sharpness in the cutting machine was cut with a Fuji Photo Film Co., Ltd. auto cutter FCT 30K for photographic support, the shape of the cut, that is, the exposed state of the pulp fiber was visually determined. . In this case, the exposed state of the pulp fiber was expressed by the grade from the least exposed grade 1 to the most exposed grade 5.

[Example 1, Example 2 and Comparative Example 1] Pulp having a zero distance tensile strength shown in Table 1 was beaten with a disc refiner to 250 ml (Canadian standard type). However, LBKP-1 is a pulp produced from maple, and LBKP-2 is a pulp produced from maple, beech and poplar. Then, a sample was prepared by adding 1.5% by weight of sodium stearate, 1.5% by weight of polyacrylamide, 0.3% by weight of polyamide polyamine epichlorohydrin, and 1.5% by weight of sulfuric acid band to the pulp by absolutely drying in a paper web. 170 g basis weight using a Fourdrinier paper machine using these samples
Paper having a thickness of / m ² and a thickness of 165 μ was produced. The surface size in the size press is polyvinyl alcohol
1.0 g / m ^{2 was} applied.

The support thus obtained was cut with an auto cutter, and the state of each cut was visually judged and graded.

As a result, as is clear from Table 1, the sharpness of the support is good when the paper is made using pulp having a small (Z-T) value that satisfies the range of the present invention, whereas (Z −
It was demonstrated that when the value of T) exceeds the present invention, the sharpness of the support becomes poor, which confirms the effect of the present invention.

[Examples 3, 4 and Comparative Example 2] Support for photographic printing paper was carried out in the same manner as in Example 1 except that the pulse used was the zero-distance tensile strength and the mixed pulp having the tensile strength shown in Table 2. A body was prepared and the sharpness of this support was visually evaluated. The mixed pulp is obtained by mixing beating pulps separately.

The results are shown in Table 2.

As is clear from the results in Table 2, the same results as in Example 1 and Comparative Example 1 described above are obtained when a mixed pulp obtained by mixing several types of pulp is used. Therefore, the effect of the present invention is clear. is there.

Claims (1)

[Claims] 1. In a support for photographic printing paper, wherein both sides of a base paper made of pulp are provided with a polyolefin resin coating layer, the pulp used for the base paper has a zero-distance tensile strength (Z) and a tensile strength (T). A support for photographic printing paper, characterized in that it is a pulp having a relationship of (Z-T) ≦ 8 kg.