JPS61290446A - Photographic printing paper base - Google Patents

Abstract

PURPOSE:To obtain a photographic printing paper base superior in resistance to chemicals by using paper board composed essentially of natural pulp containing a combination of higher fatty acid sat and a specified alkyl ketene dimer as a sizing agent, and a water-soluble aluminum salt and a specified anionic polyacrylamide for fixing the sizing agent. CONSTITUTION:As the sizing agent for the paper board composed essentially of natural pulp, the sodium or potassium sat or the like of the higher fatty acid is used in an amount of 0.1-3.0wt% of the pump, and the ketene dimer represented by the formula shown on the right (R is 8-30C alkyl) is used in combination with said acid in an amount of 0.2-1.5wt% of the pulp, and as the size fixing agent, a water-soluble aluminum compound, such as Al2(SO4)3 or AlCl3, and as the fixing assistant, the anionic polyacrylamide having a molecular weight of >=500,000 is used in an amount of 0.5-2.0wt% of the pulp to control the internal binding force of the paper board to 1.0-2.5kg.cm. It is coated with polyolefin on both sides, thus permitting the obtained paper base for the water-proof photographic printing paper to be superior in resistance to chemicals, resistant to alkali and alcohol in a developing solution and extremely smooth on the cut section.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to waterproof supports for photographic paper.

[Background of the invention] Photographic paper basically consists of a support, a silver halide emulsion layer (
It consists of a photographic emulsion layer) and a protective layer. Recently, so-called polyolefin resin-coated paper, which is a base paper mainly made of natural pulp and coated with polyethylene resin or the like as a waterproof layer on both sides, has been generally used as the support.

However, photographic paper using polyolefin resin-coated paper as a support has the problem that photographic developer easily penetrates through the cut surface of the base paper layer during the development process, and therefore edge stains are likely to occur at the edges of the photographic paper. There is. Although edge stains can be reduced by performing a long period of water washing after the development process, such a process is contrary to the recent demand for a short development process. For this reason, in photographic paper, it is strongly desired to prevent the developer from permeating through the cut surface.

In photographic printing paper, as a method for preventing permeation of a developer from the cut surface of the base paper layer, it is generally practiced to include a sizing agent in the base paper.

However, photographic developers usually contain various development aids, such as alkaline chemicals such as anhydrous sodium carbonate and sodium hydroxide as development accelerators, ethylene glycol as additives to prevent freezing of the developer, or color-forming additives. Benzyl alcohol and the like are contained for the purpose of promoting penetration of the developing agent oxide, bonding with the coupler, and color development.

Therefore, as a sizing agent for base paper for photographic paper, it is necessary to have a sizing effect on both the various alkalis and alcohols contained in the developing solution, and it must also not reduce the whiteness of the photographic paper, and must not reduce the whiteness of the photographic paper. properties such as not causing any adverse effects such as fogging are required. For this,
Rosin-based and petroleum resin-based sizing agents, which are used as sizing agents in the manufacture of general paper, tend to reduce the whiteness of photographic paper, so they cannot be used as sizing agents for base paper for photographic paper.

Sizing agents for base paper for photographic paper include higher fatty acid type sizing agents (Japanese Patent Publication No. 47-26961) and wax type sizing agents (US Pat. No. 3,241,968).
, or alkyl ketene dimer (JP-A-51-13
2822) etc. have already been reported.

Among these, higher fatty acid type sizing agents have a high sizing effect on the penetration of alcohol in the developer, but they do not show sufficient sizing effects on alkaline solutions. It is affected by the quality of the water, and if the water is hard, it will cause precipitation and cause stains in the process, so there are problems such as not being able to use it in large quantities. Wax-type sizing agents are similar to higher fatty acid-type sizing agents, and although they exhibit a high sizing effect on the penetration of alcohol in the developer, they do not exhibit sufficient sizing effects on alkaline solutions.

On the other hand, in the case of alkyl ketene dimers, the size effect is excellent with respect to the penetration of alkaline liquid in the developer, but it is significantly inferior to alcohol. In addition, unless a relatively large amount of polyamide polyamine epichlorohydrin resin, which is known as a retention agent, is used, the sizing effect will not appear even with alkaline liquid, and furthermore, it is significantly more expensive than higher fatty acid type or wax type sizing agents. There are problems such as.

As described above, the conventional base paper for photographic paper that has been treated with a sizing agent does not have sufficient chemical resistance to both the alkali and alcohol components of photographic developers, and therefore the cut surface of photographic paper using this Further improvements are desired in reducing edge staining.

[Object of the Invention] The first object of the present invention is to provide a support for photographic paper having a base paper that exhibits excellent chemical resistance to both alkaline and alcohol components of photographic developers. be.

A second object of the present invention is to provide a support for photographic paper that exhibits an extremely smooth cut surface.

[Summary of the Invention] The present invention provides a waterproof support for photographic paper in which both sides of a base paper made of natural pulp are coated with a polyolefin resin. The support for photographic paper is characterized by containing an anionic polyacrylamide having a molecular weight of 500,000 or more and an alkyl ketene dimer having 8 to 30 carbon atoms.

[Effects of the Invention] The support for photographic paper of the present invention exhibits excellent chemical resistance, especially to photographic developers. becomes extremely smooth. Therefore, photographic paper using the support for photographic paper of the present invention has excellent quality and high commercial value.

[Detailed Description of the Invention] The photographic paper support of the present invention has the following basic composition:
It has a structure consisting of a base and polyolefin resin coating layers provided on both sides of the base.

In the present invention, a base paper mainly composed of natural bulbs is used as the substrate. The base paper contains a sizing agent that has excellent chemical resistance against the alkaline and blue components of alcohol in photographic developers, and a sizing agent that increases the internal bonding strength of the base paper and prevents the photographic developer from penetrating through the cut surface of the base paper. Certain paper strength agents are added to synergistically impart properties of chemical resistance to photographic developers to the base paper.

Examples of natural pulps include wood valves, bamboo pulps, straw valves, cotton valves, flax valves, hemp pulps, Manila hemp valves, esparto valves, reed valves, bagasse valves, linter pulps, cloth valves, waste paper valves, etc. Mention may be made of the known plant JM fiber bulbs used in papermaking technology. It is possible to replace a portion of the natural pulp with synthetic fibers or synthetic valves.

Natural pulp fibers are usually made into a valve slurry by mechanically beating the valve in water using a beater or the like.

The degree of beating is usually determined using a Canadian standard freeness tester.
Measure the freeness (Canadian freeness) (unit: C
C) Ask.

The natural pulp used in the present invention preferably has a Canadian freeness of 150 to 450 cc, particularly preferably a Canadian freeness of 250 to 350 cc.

In the present invention, a higher fatty acid salt and an alkyl ketene dimer are used in combination as a sizing agent.

As the higher fatty acid salt and the alkyl ketene dimer, those commonly used as sizing agents in the paper manufacturing field can be used.

The higher fatty acid salt preferably has carbon atoms in the range of 12 to 22. Examples include sodium or potassium salts of tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, and the like.

The preferable amount of higher fatty acid salt added is 0.
1 to 3.0% by weight, particularly preferably 0.5 to 2% by weight.
．． It is 0% by weight.

The alkyl ketene dimer used in the present invention is represented by the following general formula (1).

RCH=C--0 In the general formula (1), R represents an alkyl group having 8 to 30 carbon atoms. Examples of such alkyl ketene dimers include JP-A-51-132822 and Tappi (
Appi), Volume 39, No. 1 (Vat 39,
) (1956), pages 21-23.

In the present invention, among such alkyl ketene dimers, it is preferable to use those in which the number of carbon atoms in the alkyl group is in the range of 12 to 18. The preferred amount of the alkyl ketene dimer added is 0.05 to 2.0% by weight, particularly preferably 0.2 to 1.5% by weight, based on the bulb.

Alkyl ketene dimers are usually commercially available as mixtures of compounds having alkyl groups having various carbon numbers, and in the present invention, either such a mixture or a single substance can be used.

The sizing agent is added to the bulb using a known method, such as a method in which the sizing agent is uniformly dispersed as an aqueous solution in a bulb slurry diluted with water after beating while stirring.

Note that the higher fatty acid salt and the alkyl ketene dimer may be used by being mixed in advance, or may be added separately.

In order to fix the sizing agent to pulp fibers in the present invention, a water-soluble aluminum salt is used as a fixing agent. Examples of water-soluble aluminum salts include aluminum sulfate and aluminum chloride.

The preferred amount of fixing agent used is 1.0 based on the weight of the pulp.
~3.0% by weight.

In order to fix the sizing agent in the present invention to the pulp fibers, it is necessary to further add polyamide polyamine epichlorohydrin, which is known as a fixing aid, to the pulp in an amount of 0.1 to 1.
．． It is preferable to add 0% by weight.

Furthermore, when a cationic sizing agent obtained by the reaction of aliphatic carboxylic acid and a polyvalent amine is used in combination, the sizing effect of the present invention can be further enhanced, and can be used as necessary.

In the present invention, the base paper further contains anionic type polyacrylamide. As the anionic type polyacrylamide, for example, those described in detail in "Resin for Paper and M-cone Processing and its Test Method" (Shokodo, 1968), page 283, can be used. An example is heating polyacrylamide in the presence of an alkali,
partially hydrolyzed, acrylamide/acrylic acid copolymer, acrylamide/methacrylic acid copolymer,
Acrylamide/maleic acid copolymer can be mentioned. Furthermore, terpolymer copolymers in which a seven-unit unit such as acrylonitrile or acrylic acid ester is further introduced into these copolymers can also be used.

The anionic polyacrylamide used in the present invention has a molecular weight of 500,000 or more.

Preferably, those having a molecular weight in the range of 600,000 to 1,000,000 are used. The method of adding anionic type polyacrylamide is to uniformly disperse an aqueous solution of anionic type polyacrylamide into a pulp slurry diluted with water before and after adding the sizing agent, and to add the amount of anionic type polyacrylamide added. is 0.3 to 3.
It is preferable to add 0% by weight, particularly preferably 0% by weight.
It is 5 to 2.0% by weight.

In the present invention, in addition to the above-mentioned additives, known additives generally used in paper manufacturing technology, such as fillers, dyes, fluorescent dyes, antistatic agents, etc., may be added to the pulp slurry as necessary. The good pulp slurry is then made into base paper using a paper machine according to generally known papermaking techniques.

The base paper used in the photographic paper of the present invention has a basis weight of 60 to 200.
g/rrf, and its internal bond strength is 1.0~
2.5 kg Cm is preferable, and the internal bond strength is 1.
If it is smaller than 0 kgmcm, the cut surface tends to be defective, which tends to increase edge stains, and
If the internal bonding strength is made too high, the flatness of the base paper tends to decrease.

A polyolefin resin coating layer is then provided on both sides of the base paper to provide a waterproof support for photographic paper.

As the polyolefin resin, polyethylene is preferable, and the coating amount thereof is preferably about 10 to 50 g/rrf. Furthermore, examples of the coating method include known coating methods such as air doctor coating, kiss coating, cast coating, and spray coating.

Next, Examples and Comparative Examples of the present invention will be shown.

[Examples 1 to 4] A mixture of wood pulps (LBKP/NBSP=2/1, weight ratio) was beaten to obtain a valve slurry of 260 cc of Canadian freeness.

After diluting this valve slurry with water, while stirring,
In this, sodium stearate, anion type polyacrylamide (Polystron 194 manufactured by Arayo Kagakumai,
(molecular weight 700,000), aluminum sulfate, polyamide polyamine epichlorohydrin (Kymen 557, manufactured by Dick Vercules), and alkyl ketene dimer (manufactured by Dick Vercules, Acopel, with alkyl groups having 14 and 16 carbon atoms) (mixed at a ratio of 2:l)
Each of these was added as an aqueous solution in the amounts shown in Table 1 in this order.

Next, the above pulp slurry was made into a 170 g/m' base paper.

Then, coat the back side of the base paper with polyethylene with a density of about 0.980 g/C to a thickness of about 0.033 mm,
The outer surface contains 10% by weight of titanium dioxide and has a density of approximately 0.
．． Approximately 0.033mm of 960g/cm'' polyethylene
A waterproof support for photographic paper was obtained.

[Comparative Examples 1 to 6] A pulp slurry was prepared using the same pulp mixture as that used in Example 1 and in the same manner.

Next, as shown in Table 1, the additives were added to the pulp slurry in the same manner as in Example 1, except that some of the additives used in Example 1 were excluded, and the amount of additives was changed depending on the case. agent was added.

A base paper was produced in the same manner as in Example 1 using the above pulp slurry, and then a waterproof support for photographic paper was obtained.

Table 1 ABCD ・E 1 1.0 1.0 1.5 0.3 0.52
1.0 1.0 1.5 0.3 0.73
1.0 1.5 1.5 0.3 1.04 2.
0 1.5 1.5 0.3 0゜71 1.0
- 1.5 - -2 2.0 - 1.5
0.3 -3 1.0 0.5 1.5 0.3
-4 - - - 0.3 0.75
-- 1.5 0.3 0.76 - 1.
0 1.5 Q, 3 0.7 (values are % by weight of pulp)
) Note) A: Sodium stearate B: Anionic polyacrylamide C: Aluminum sulfate D = Polyamide polyamine Epichlorohydrin E: Argyl ketene dimer [Evaluation of base paper and photographic paper] First, examine the inside of the base paper before resin coating. The bond strength (tensile strength in the [Z-axis] direction perpendicular to the plane of the base paper) was measured.

The internal bonding strength of base paper is measured using the Tappusuful method (
The test was carried out using an internal pond tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) according to Tappi Useful Method 529.

Next, the edge stain and cut surface of the photographic paper support were evaluated.

To evaluate edge stains, photographic paper supports cut into 8.25 cm widths are developed using Noritsu Koki's color paper automatic processor (RPV-409 model), and the permeation distance of the developer from the cut portions is measured using a magnifying glass. The measurements were carried out visually using a .

The cut surface was evaluated by cutting the developed photographic paper support with an automatic cutter made by Copal ■ and observing the shape of the cut surface (the state of occurrence of whiskers of pulp fibers) with the naked eye. .

The results obtained are shown in Table 2.

From the results in Table 2, it is clear that any one of higher fatty acid salts, water-soluble aluminum salts, anionic polyacrylamide with a molecular weight of 500,000 or more, and alkyl ketene dimers with a carbon number of 8 to 30 can be added to the base paper. It can be seen that the support for photographic paper that is not coated is more susceptible to penetration of the developer.

Margin below

Claims (1)

[Scope of Claims] 1. A waterproof support for photographic paper, in which both sides of a base paper made of natural pulp are coated with a polyolefin resin, wherein the base paper contains a higher fatty acid salt, a water-soluble aluminum salt,
A support for photographic paper, comprising an anionic polyacrylamide having a molecular weight of 500,000 or more and an alkyl ketene dimer having 8 to 30 carbon atoms. 2. The molecular weight of anionic polyacrylamide is 60
The support for photographic paper according to claim 1, characterized in that the molecular weight is in the range of 10,000 to 1,000,000. 3. The support for photographic paper according to claim 1, wherein the content of anionic polyacrylamide is in the range of 0.5 to 2.0% by weight based on the pulp. 4. The support for photographic paper according to any one of claims 1 to 3, wherein the anionic polyacrylamide is a partial hydrolysis product of polyacrylamide. 5. The support for photographic paper according to any one of claims 1 to 3, wherein the anionic polyacrylamide is a copolymer of acrylamide and acrylic acid. 6. The photograph according to any one of claims 1 to 3, wherein the content of alkyl ketene dimer is in the range of 0.2 to 1.5% by weight based on the pulp. Support for photographic paper. 7. The support for photographic paper according to any one of claims 1 to 3, wherein the base paper has an internal bonding force of 1.0 to 2.5 kg·cm.