JPH08146555A - Supporting body for photographic paper - Google Patents

Abstract

PURPOSE: To prevent the permeation of a developer and the deterioration of whiteness of a supporting body, and improve the strength and texture, by using specific N-vinylformamide.vinylamine copolymer for a fixer. CONSTITUTION: In an original paper, one or more sorts of alkylketene dimer or alkenyl succinic acid anhydride is contained as size paper, and N- vinylformamide vinylamine copolymer of vinylamine unit over 50mol% and mean molecular weight 50000-15000 is contained as a size fixer of the size paper. In this size fixer, two or more sorts of N-vinylformamide.vinylamine copolymers of different basic hydrolysis rate are used together. Hereby, yield of the size paper and manifestation of size are improved. In addition, because invasion of a developer can be prevented by a little adding quantity of size paper, deterioration of strength can be restrained even if a wet strengthening agent for paper is not added. Further, the strength can be also improved, by using together anionic or amphoteric polyacrylamide.

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 having a base paper coated on both sides with a polyolefin resin. More specifically, the present invention relates to a photographic printing paper support which prevents penetration of a developing solution, does not reduce the whiteness of the support, and has high strength and texture.

[0002]

2. Description of the Related Art Conventionally, as a support for photographic printing paper,
Although base papers excellent in appearance, stiffness, strength and price are used, it is mentioned that these base papers also have a large absorption of the developing solution. Rapid development,
It is not preferable that the processing liquid be absorbed in the support from the viewpoint of preservation of print quality.

As a countermeasure against this, it is widely practiced to coat both sides of the base paper with a waterproof resin such as polyolefin. However, although this method can prevent the development processing solution from entering from the front and back surfaces, it cannot prevent the development processing solution from entering from the end portions of the support. Further, in the recent water-saving type water washing treatment, it is impossible to completely wash the treatment liquid that has penetrated from the end portion.

For the purpose of preventing the infiltration of the processing liquid from the end,
A sizing agent is added to the base paper. At this time, from the viewpoint of the storability of the photographic printing paper, reflecting the fact that neutral paper is preferable, the use of a neutral sizing agent that exerts an effect in a neutral to weakly alkaline region is increasing. The neutral sizing agent used for the base paper of the support for photographic printing paper must satisfy the following conditions. That is, it has a sufficient size effect on the developing solution, does not cause the coloring by adsorbing the developing solution, and does not adversely affect the photographic properties such as fog. In addition, a sizing agent that does not reduce the strength of the base paper is more preferable, and an alkyl ketene dimer or an alkenyl succinic anhydride is generally used.

A size fixing agent (hereinafter abbreviated as a fixing agent) is used for the purpose of enhancing the size effect with respect to the above sizing agent used in a neutral to weakly alkaline atmosphere.
Conventionally, it has been common to add a strong cationic substance such as a polyamide polyamine epichlorohydrin condensate or polyethyleneimine. However, the addition of these size fixing agents is often insufficient.

For example, in Japanese Patent Publication No. 62-23119, anionic polyacrylamide, aluminum salt,
Method for adding alkaline substance, JP-A-5-17328
Japanese Patent Publication No. 7 discloses a method of achieving both high size and smoothness by using a cationic polyacrylamide or an anionic polyacrylamide and an alkaline substance. However, in these methods, since the yield and expression of the sizing agent are insufficient, the added amount of the sizing agent and the fixing agent becomes excessive, and the chemical cost and effect are not always manufactured under the optimum conditions. is there.

[0007]

As described above, as the fixing agent for the sizing agent, cationic starch, polyamine epichlorohydrin resin, cationic polyacrylamide,
The base paper obtained by using the anionic polyacrylamide alone or by using several kinds thereof is high in cost even if the size is sufficient. At present, the size is not always satisfactory for the added amount.

According to the present invention, at least one sizing agent of an alkyl ketene dimer or an alkenyl succinic anhydride and an N-vinylformamide / vinylamine copolymer are contained as a fixing agent for the sizing agent to develop from the end portion. Effectively prevent the invasion of the processing solution. In addition, by using the anionic or amphoteric polyacrylamide in combination, the invasion of the development processing solution from the end is further effectively prevented, and the formation and the internal strength are excellent. The purpose is to provide a support for photographic paper.

[0009]

DISCLOSURE OF THE INVENTION As a result of intensive investigations by the present inventors to use various cationic resins as fixing agents in view of the above, the N-vinylformamide / vinylamine copolymer used in the present invention is used as a fixing agent. The yield of the sizing agent and the expression of the size are improved by using as the sizing agent, and it is possible to prevent the infiltration of the developing solution with a small addition amount of the sizing agent, so that the strength reduction can be suppressed without adding the wet paper strength agent, Further, they have found that when anionic or amphoteric polyacrylamide is used in combination as a dry paper strength agent, the strength can be further improved, and the present invention has been completed.

The sizing agent used in the present invention comprises a ketene dimer having an unsaturated or branched olefin or an α-olefin as a hydrophobic group, succinic anhydride starch, a water-soluble polymer and the like as protective colloids. It is an aqueous dispersion. The sizing agent is excellent in that an effective sizing degree can be obtained with a small amount of addition and that the sizing agent is sized with respect to an alkaline solution and a solvent. Recently, a rosin-modified sizing agent that develops a size even in a neutral region has been developed, but the sizing property for an alkaline solution such as a developer is insufficient. Further, a sizing agent such as an epoxidized higher fatty acid amide, which has a relatively good sizing property with respect to an alkaline solution and a solvent, causes a strong decrease in strength and strength of the support, and requires the use of a paper strength agent in combination.

N-vinylformamide used in the present invention
As the vinylamine copolymer, conventionally known is a method of producing it by Hoffmann decomposition of polyacrylamide, hydrolysis of poly N-vinylformamide, or the like. In particular, N
-A method for hydrolyzing a polymer of vinylformamide is
This is an excellent method for producing a stable polyvinylamine. To produce polyvinylamine, N-
A method in which vinylformamide is polymerized in an aqueous solution and the resulting water-soluble polymer is hydrolyzed is used, but in the present invention, hydrolysis is carried out with a base.

Regarding the hydrolysis, there are a method of carrying out with an acid and a method of carrying out with a base, but in the case of an acid, it becomes a salt type, and hydrolysis with a base which becomes a free amine type is preferable as the present fixing agent.

The N-vinylformamide / vinylamine copolymer having a primary amine as the main component of the cation does not lose its cationic property although it is weak even in an alkaline atmosphere, and has a whiteness due to yellowing of paper such as polyethyleneimine. In addition, the N-vinylformamide / vinylamine copolymer having a vinylamine ratio of 50 mol% or more does not cause a decrease, and the effect of fixing an alkyl ketene dimer or an alkenyl succinic anhydride type neutral sizing agent, and The expression was found to be significant.

The addition amount of each of the sizing agent (A) and the fixing agent (B) is 0.3% by weight or more based on the solid content of pulp to obtain a sufficient sizing degree, and the weight ratio (B / If A) is less than 0.5, the amount of the fixing agent with respect to the sizing agent will be insufficient, and if it exceeds 3.0, the amount of the fixing agent with respect to the sizing agent will be excessive, resulting in economically meaningless addition. In the present invention, it has been found that by using the weight ratio of the addition amount of the sizing agent and the fixing agent in the range of 0.5 to 3.0, it is possible to more effectively prevent the infiltration of the developing solution.

The tertiary and quaternary amines which are generally used as a fixing agent for the sizing agent are cationic in the range of weak acidity of pH 6.5 to alkalineity of pH 9.0, which is also the scope of the present invention. There is. When a base paper for a photographic printing paper support is paper-made using these fixing agents, if the addition amount of the fixing agent is increased to obtain a desired sizing degree, cations of the paper-making system become excessive, which is not preferable. But,
The N-vinylformamide / vinylamine copolymer does not disturb the system even if added in a large amount, and the size fixing effect does not significantly change. Further, it is most effective to carry out papermaking at pH 7.6 to 8.0. There was found. Also, the pH is 5.0
Alkyl ketene dimer does not provide sufficient size when papermaking is performed in the following completely acidic atmosphere, and alkenyl succinic acid is used when papermaking is performed in a completely alkaline atmosphere having a pH of 9.0 or more. It is a well-known fact that an anhydride does not provide sufficient size.

Further, it has been discovered that a more excellent size effect and paper strength enhancing effect can be obtained by using the N-vinylformamide / vinylamine copolymer and anionic polyacrylamide or amphoteric polyacrylamide in combination, and the present invention It came to completion.

The anionic or amphoteric polyacrylamide used in the present invention means a homopolymer of acrylamide or a partial hydrolyzate of a copolymer of vinyl monomer and acrylamide copolymerizable with acrylamide, or acrylamide and acrylic acid. A copolymer with methacrylic acid or the like, or anionic polyacrylamide or acrylamide or methacrylamide obtained by partially substituting a part of acrylamide with acrylonitrile, acrylic ester, etc., a water-soluble cationic monomer, α, β-unsaturated mono And a water-soluble polymer having cation group and anion group as the main monomer component of acrylamide or methacrylamide obtained by copolymerizing a mixture of dicarboxylic acid and the like. The water-soluble polymer may be a polymer that is generally on the market, but the colloid titration value measured at pH 9.0 is more preferably -0.5 meq / g or less.

If the weight ratio (B / C) of the added amount of the fixing agent (B) and the paper strength agent (C) is less than 2.0, the amount of the paper strength agent with respect to the fixing agent becomes excessive, which is sufficient. 5. Not only the strength cannot be improved but also the addition is economically meaningless.
If the amount is more than 0, the amount of the paper-strengthening agent added to the fixing agent will be small and the strength cannot be expected to be improved. Therefore, in the present invention, the addition ratio of the fixing agent and the paper-strengthening agent is 2.0 to 6.0. It has been found that this makes it possible to more effectively prevent the infiltration of the developing solution and further improve the strength of the base paper.

The pulp used in the base paper for photographic printing paper of the present invention includes NBKP, LBKP, NBSP,
LBSP, TMP, waste paper, etc. may be mentioned. In use, several of them are mixed at a ratio according to the purpose and used. In addition, kaolin, talc, fillers such as calcium carbonate and titanium oxide, which are usually used in papermaking, dyes, sizing agents, fixing agents, wet paper strengthening agents, dry paper strengthening agents and the like can be contained as necessary. .

[0020]

Function: Although the detailed mechanism is not clear, N-
The vinylformamide / vinylamine copolymer has a structure in which two vinylamines exist continuously, so that it does not completely lose its cationic property even in an alkaline atmosphere. Furthermore, since the amine density per molecular weight is high, it has a neutral size. It is believed possible that the agent can be adsorbed and fixed on the pulp fibers.

[0021]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples. The present invention is not limited to the embodiments. All parts and% in the following are by weight. The fixing agent used will be described below prior to the examples and comparative examples.

Fixing Agent 1 Weight as calculated from the value of reduced viscosity measured at 25 ° C. as a solution containing 95% of vinylamine units and 5% of N-vinylformamide units and 0.1 g / dl in 1N saline solution. Average molecular weight (hereinafter abbreviated as molecular weight) 140,00
12% aqueous solution of copolymer having 0. PH of this aqueous solution
Was 6.5.

Fixing agent 2 A 12% aqueous solution of a copolymer containing 98% vinylamine units and 2% N-vinylformamide units and having a molecular weight of 58,000. The pH of this aqueous solution was 5.6.

Fixing Agent 3 12% aqueous solution of a copolymer containing 72% vinylamine units and 18% N-vinylformamide units and having a molecular weight of 58,000. The pH of this aqueous solution was 6.1.

Fixing Agent 4 12% aqueous solution of a copolymer containing 60% vinylamine units and 40% N-vinylformamide units and having a molecular weight of 100,000. The pH of this aqueous solution was 6.3.

Fixer 5 A 12% aqueous solution of a copolymer containing 98% vinylamine units and 2% N-vinylformamide units and having a molecular weight of 160,000. The pH of this aqueous solution was 5.6.

Fixing Agent 6 A 12% aqueous solution of a copolymer containing 42% vinylamine units and 58% N-vinylformamide units and having a molecular weight of 58,000. The pH of this aqueous solution was 6.2.

Example 1 LB beaten with a PFI mill to a freeness of 380 mlc.sf
Alkyl ketene dimer (trade name: AS24) was used as a sizing agent for pulp solids in which KP and NBKP beaten to 450 mlc.sf were mixed at a weight ratio of 7: 3.
A, manufactured by Japan PMC), 0.4%, fixing agent 2 / fixing agent 3
0.4% / 0.2% of a combined N-vinylformamide / vinylamine copolymer was added, and an anionic paper strength agent (trade name: Stargum A15, manufactured by Seikou Kagaku Co., colloid titration value-1.35 meq / g) was added 0.2% and sodium carbonate was added in an appropriate amount to adjust the pH to 7.6, and then a base paper having a basis weight of 180 g / m ² was produced.

The obtained base paper was calendered to a density of 1.0 g / cm ³ , and low-density polyethylene was extruded and coated on the front and back surfaces to a thickness of 30 μm to support the photographic printing paper of Example 1. I made it a body.

Example 2 The addition amount of the anionic paper strength agent used in Example 1 was 0.1%.
Example 2 by the same method as in Example 1 except that
To obtain a support for photographic printing paper.

Example 3 A photographic paper support of Example 3 was obtained in the same manner as in Example 1 except that the amount of the sizing agent used in Example 1 was changed to 0.2%.

Example 4 The addition amount of the N-vinylformamide / vinylamine copolymer of the fixing agent 2 / fixing agent 3 combination system used in Example 2 was adjusted to 0.
A support for photographic printing paper of Example 4 was obtained in the same manner as in Example 2 except that 33% / 0.17% was used.

Example 5 The amount of the sizing agent used in Example 1 was 0.6%, and N was added.
Example 1 except that the combination system of vinylformamide / vinylamine copolymer was used as the fixing agent 1 alone system, the addition amount was changed to 0.3%, and the addition amount of the anionic paper strength agent was changed to 0.15%. A support for photographic printing paper of Example 5 was obtained by the same method as described above.

Example 6 Example 1 was repeated except that the fixing agent 2 / fixing agent 3 combination system N-vinylformamide / vinylamine copolymer was used in Example 1 instead of the fixing agent 4 / fixing agent 3 combination system. A support for photographic printing paper of Example 6 was obtained by the same method.

Example 7 In place of the anionic paper strength agent used in Example 1, 0.2% of an amphoteric paper strength agent (trade name: DS716, manufactured by Japan PMC, colloid titration value-1.02 meq / g) was added. A support for photographic printing paper of Example 7 was obtained in the same manner as in Example 1 except that the above was carried out.

Example 8 The sizing agent used in Example 1 was a mixture of an alkenyl succinic anhydride type sizing agent (trade name: Coropearl Z100, manufactured by Seikou Kagaku Co., Ltd.) and a cationic starch (trade name: Cato 2, manufactured by Oji Corn Starch Co., Ltd.). Was replaced with a sizing agent emulsified with a turbine homogenizer and the amount added was changed to 0.5% to obtain a support for photographic printing paper of Example 8 by the same method as in Example 1.

Example 9 The same method as in Example 1 except that the amount of sodium carbonate added was adjusted to adjust the papermaking pH to 7.6 and no anionic paper strength agent was added. Thus, a support for photographic printing paper of Example 9 was obtained.

Example 10 Except that sodium carbonate was not added in Example 1, and the pH of papermaking was adjusted to 6.0 by adjusting the addition amount of the sulfuric acid band.
A support for photographic printing paper of Example 10 was obtained in the same manner as in Example 1.

Example 11 A photographic paper support of Example 11 was prepared in the same manner as in Example 1 except that the amount of sodium carbonate added was adjusted to adjust the papermaking pH to 6.5. Obtained.

Example 12 A photographic paper support of Example 12 was prepared in the same manner as in Example 1 except that the amount of sodium carbonate added was adjusted to adjust the papermaking pH to 8.6. Obtained.

Example 13 A photographic paper support of Example 13 was prepared in the same manner as in Example 1 except that the amount of sodium carbonate added was adjusted to adjust the papermaking pH to 9.0. Obtained.

Example 14 In Example 1, the sodium carbonate was changed to sodium hydroxide,
A support for photographic printing paper of Example 14 was obtained in the same manner as in Example 1 except that the papermaking pH was adjusted to 10.0 by adjusting the addition amount of this.

Example 15 In Example 1, the N-vinylformamide / vinylamine copolymer combination system was used as the fixing agent 1 alone system, and the addition amount was 0.15%.
Example 15 by the same method as in Example 1 except that
To obtain a support for photographic printing paper.

Comparative Example 1 Comparative Example 1 was carried out in the same manner as Comparative Example 1 except that the N-vinylformamide / vinylamine copolymer used in Example 9 was changed to the fixing agent 5 and the addition amount was 0.2%. To obtain a support for photographic printing paper.

Comparative Example 2 The amount of the sizing agent used in Example 1 was changed to 0.5%, and the N-vinylformamide / vinylamine copolymer was changed to an epichlorohydrin compound (trade name: WS570, manufactured by Nippon PMC) and added. A photographic printing paper support of Comparative Example 2 was obtained in the same manner as in Example 1 except that the amount was 0.5% and no anionic paper strength agent was added.

Comparative Example 3 The addition amount of the sizing agent used in Example 1 was changed to 0.5%, the N-vinylformamide / vinylamine copolymer was changed to an epichlorohydrin compound, and the addition amount was changed to 1.0%. A support for photographic printing paper of Comparative Example 3 was obtained in the same manner as in Example 1 except that the strength agent was not added.

Comparative Example 4 The addition amount of the sizing agent used in Example 1 was changed to 0.5%, the N-vinylformamide / vinylamine copolymer was changed to an epichlorohydrin compound, and the addition amount was changed to 0.5%, anionic paper strength. A support for photographic printing paper of Comparative Example 4 was obtained in the same manner as in Example 1 except that the amount of the agent added was 0.5%.

Comparative Example 5 The amount of the sizing agent used in Example 1 was changed to 0.5%, and the N-vinylformamide / vinylamine copolymer was changed to a polyethyleneimine compound (trade name: Polymine SK, manufactured by BASF). A support for photographic printing paper of Comparative Example 5 was obtained in the same manner as in Example 1 except that the amount added was 0.5%.

Comparative Example 6 The N-vinylformamide / vinylamine copolymer combination system used in Example 1 was used as the fixing agent 2 / fixing agent 3 to fixing agent 2
/ A support for photographic printing paper of Comparative Example 6 was obtained by the same method as in Example 1 except that the fixing agent 6 was used.

The types of fixing agents, sizing agents and paper strength agents used in Examples 1 to 15 and Comparative Examples 1 to 6 and their addition amounts, and the papermaking pH are shown in Tables 1 and 2 below.
The support for photographic printing paper obtained above was evaluated by the following evaluation methods, and the results are shown in Table 3.

[Size Degree] The size degree is a processing solution from the end of the photographic printing paper support after the photographic printing paper support is developed by an automatic processor (FC Co., color roll processor). The penetration depth was measured and judged. In order to maintain an excellent appearance, 0.50 mm or less, more preferably 0.45 mm or less is required.

[Whiteness] Using a Hunter reflectometer (manufactured by Toyo Seiki Co., Ltd.), the whiteness was measured according to the method of JIS-P8123. As a base paper for a photographic printing paper support, 87% or more, and more preferably 90% or more is necessary in order not to reduce the commercial value after printing.

[Internal Strength] The internal strength considered to be necessary when developing the photographic paper with a color roll processor is an internal bond tester (manufactured by Kumagai Riki Kogyo Co., Ltd.).
It measured using. The unit is g-cm / in ² . The strength required for photographic paper is 350 g-cm / in ² or more, more preferably 380 g-cm / in ² or more.

[Formation] Soft X-ray generator (SOFTEX-
CMR: Model LJX-101), 12 × 17c
X-ray film was pressure-bonded to the sample of m, the tube voltage was 5 KV, the emission current was 6 mA, and the irradiation time was 30 mi.
n. The X-ray film obtained by irradiating with X-ray was developed, and the density variation count was obtained from the image on the film using an image analyzer (LUZEX 50X). Enter the density fluctuation count at 5 points from one film,
Evaluation was performed by the average value of the values calculated in. Generally, in order to maintain an excellent appearance, the density variation coefficient is preferably 10% or less.

[0055]

[Equation 1] Concentration fluctuation count (%) = (standard deviation / average concentration) × 100

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

Evaluation: N- having a vinylamine unit of 50 mol% or more and a molecular weight of 50,000 to 150,000.
When a vinylamide / vinylamine copolymer is also used as a fixing agent for the sizing agent, it is possible to suppress the permeation of the developing solution from the end portion of the photographic printing paper support as in Examples 1 to 4, As described above, it can be seen that even when used alone, the texture is slightly deteriorated, but a sufficient size is obtained.

Further, in the comparative examples 2 to 4 of the commonly used epichlorohydrin type cationic fixing agents, sufficient sizing degree cannot be obtained, and the polyethyleneimine of the comparative example 5 has good sizing property. Although it can be obtained, it can be seen that the whiteness of the base paper is so large that it cannot be put to practical use.
Further, by comparing Example 15 with Examples 1 to 6,
It can be seen that a sufficient sizing degree can be obtained when the fixing agent is added in an amount of 0.3% by weight or more. Furthermore, Comparative Example 1,
It can be seen from 6 that the N-vinylamide / vinylamine copolymer having a vinylamine unit and a molecular weight outside this range does not provide sufficient size and texture.

By comparing Examples 1 to 7 with Example 9, when the N-vinylamide / vinylamine copolymer is used, the sizing degree is improved, but when anionic polyacrylamide or amphoteric polyacrylamide is used in combination. It can be seen that a further improvement in sizing degree and strength can be achieved. Also, as shown in Example 8, a good sizing degree can be obtained even with an alkenyl succinic anhydride type sizing agent.

From Examples 11-13, papermaking pH 6.5-
Although 9.0 shows a good sizing property, as shown in Examples 10 and 15, the sizing degree tends to decrease outside the range of the paper making pH.

[0063]

By using the N-vinylformamide / vinylamine copolymer used in the present invention as a fixing agent for an alkyl ketene dimer or an alkenyl succinic anhydride type sizing agent, the yield of the sizing agent and high size are required. It has been found that the support for photographic printing paper according to the present invention improves not only the development of size but also the formation. In addition, since it is possible to prevent the development processing solution from entering with a small amount of the sizing agent, the production cost is reduced, and since the strength is not reduced due to the excessive addition of the sizing agent, it is necessary to add a wet strength agent for compensating the paper strength. Disappears. In addition, the strength can be further improved by using a dry paper strength agent of anionic or amphoteric polyacrylamide in combination.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03C 1/79

Claims (5)

[Claims] 1. A support for a photographic printing paper, wherein both sides of a base paper are coated with a polyolefin resin, in the base paper, at least one or more of alkyl ketene dimer or alkenyl succinic anhydride as a sizing agent, and the size of the sizing agent. N- having a vinylamine unit of 50 mol% or more and a weight average molecular weight of 50,000 to 150,000 as a fixing agent
A support for photographic paper, comprising a vinylformamide / vinylamine copolymer. 2. The photographic paper support according to claim 1, wherein the size fixing agent is a combination of two or more kinds of N-vinylformamide / vinylamine copolymers having different base hydrolysis rates. . 3. A size agent (A) and a size fixing agent (B)
The addition amount of each is 0.3% by weight per pulp solid content
Above, and the weight ratio (B / A) of the added amount is
It is 0.5-3.0, The claim 1 or 2 characterized by the above-mentioned.
A support for the photographic paper described. 4. The base paper contains anionic or amphoteric polyacrylamide as a paper-strengthening agent, and the weight ratio (B) of the added amounts of the size-fixing agent (B) and the paper-strengthening agent (C).
/ C) is 2.0 to 6.0, The photographic printing paper support according to claim 1. 5. The support for photographic printing paper according to claim 1, wherein the raw paper has a papermaking pH of 6.5 to 9.0.