JP2005266207A - Support for photographic printing paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support for photographic printing paper having few defects caused when a polyolefin resin is laminated on base paper, excellent in appearance of a surface to be coated, and excellent also in suitability to cutting, sizing property/tactile sensation against penetration of a developing solution. <P>SOLUTION: Paper obtained by applying 1.4-2.6 g/m<SP>2</SP>, solid basis, of modified starch based on rhizome starch onto a surface of paper to which at least an alkyl ketene dimer has been added as a sizing agent is used as base paper. Calcium carbonate is preferably incorporated into the paper in an amount of 0.3-5.0 mass%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a support for photographic paper. More specifically, by using as a base paper a paper in which a modified starch mainly composed of rhizome starch is applied to the surface of a paper to which at least an alkyl ketene dimer is added as a sizing agent in a solid content of 1.4 to 2.6 g / m ^2. The present invention provides a support for photographic printing paper that has an excellent appearance on the surface on which the emulsion is applied and is excellent in cutting properties, size properties, and hand feeling.

  The base paper of the photographic paper support is given a sizing property so that when the photographic paper is subjected to a development process, the developing solution penetrates from the edge portion and does not change color. . As a sizing agent that imparts sizing properties, an alkyl ketene dimer is considered desirable in terms of size effect.

  However, when a base paper using an alkyl ketene dimer as a sizing agent is used to laminate a polyolefin resin on the surface of the base paper, there may be a problem of soiling the paper roll of the processing machine. If the dirt accumulated on the surface of the paper roll grows large on the roll, it will fall off the surface of the running base paper and remain as foreign matter, or a mold will be formed on the base paper surface, and it will be indented after laminating the polyolefin resin. May remain as. The support for a photographic printing paper in which these foreign matters and dents remain has a markedly impaired appearance.

  When an alkyl ketene dimer is added as a sizing agent, interfiber bonding between pulp fibers is inhibited, and in particular, when the fine fibers are selectively adsorbed, the fine fibers easily fall off from the base paper surface. In the post-process, problems such as “foreign matter” and “mold” are likely to occur due to the dropping of fine fibers. Further, the strength of the entire base paper is reduced, the rigidity of the base paper is lowered, and the hand feeling of the entire photographic paper is impaired.

As means for solving the above problem, there is a conventional method for changing the type of alkyl ketene dimer (for example, Patent Document 1), but the effect is not sufficient. In order to increase the surface strength of the base paper surface, it may be possible to increase the amount of binder attached in the size press in the paper making process of the base paper, but when the amount of binder attached to the size press increases. In the laminating process of polyolefin resin, the adhesiveness between the polyolefin resin and the base paper is lowered, and the polyolefin resin is peeled off from the base paper at the cut end when the post-process of the support for the photographic printing paper of the present invention is performed. Problems arise. Also, if the adhesion between the polyolefin resin and the base paper is not sufficient, even if the base paper itself has a sufficient size, the developer selectively permeates in the developing unit at the interface between the polyolefin resin and the base paper, and the edge portion Problems such as discoloration occur.
JP-A-63-112796

  Accordingly, the object of the present invention is that there are few defects when processing a polyolefin resin on a base paper, the appearance of the coated surface is excellent, the cutting property, the sizing property and the resistance to penetration of the developer. An object of the present invention is to provide a photographic paper support having an excellent texture.

As a result of intensive studies to solve the above problems, the present inventor solidified modified starch mainly composed of rhizome starch on the surface of paper to which at least alkyl ketene dimer was added as a sizing agent. By using paper coated with 4 to 2.6 g / m ² as a base paper, and more desirably containing 0.3 to 5.0% by mass of calcium carbonate in the paper, the appearance of the surface on which the emulsion is coated is improved. Provided is a photographic paper support that is excellent in cutting properties, size characteristics against penetration of developer, and hand feeling.

The support for photographic printing paper of the present invention was obtained by applying 1.4 to 2.6 g / m ^{2 of} a modified starch containing rhizome starch as a main component on the surface of paper to which at least an alkyl ketene dimer was added as a sizing agent. By using paper as a base paper, and more desirably, by containing 0.3 to 5.0% by weight of calcium carbonate in the paper, the appearance of the surface on which the emulsion is applied is excellent, and the cutting property and soaking of the developing solution are achieved. It is possible to provide a photographic paper support that is excellent in size and hand feeling against the texture.

The photographic paper support of the present invention will be described in detail below.
In the photographic paper support of the present invention, the base paper of the photographic paper support is such that when the photographic paper is subjected to a development treatment, the developer soaks from the edge portion and does not change color. In order to do so, size is given. As a sizing agent that imparts sizing properties, an alkyl ketene dimer is considered desirable in terms of size effect. However, as a drawback of the alkyl ketene dimer, there is a problem of “paper roll contamination” and “foreign matter” described above.

Therefore, the present inventors have made extensive studies to solve these problems while taking advantage of the preferred size effect of the alkyl ketene dimer, and as a result, the surface of the paper to which at least the alkyl ketene dimer was added as a sizing agent, By using as a base paper a paper coated with 1.4 to 2.6 g / m ^{2 of} a modified starch containing starch as a main component, 0.3 to 5.0% by mass of calcium carbonate is more desirably contained in the paper. It has been found that it is possible to provide a support for photographic paper that is excellent in the appearance of the surface on which the emulsion is applied, and that is excellent in cutting property, size property against penetration of developer, and hand feeling. .

The present inventors first examined a binder of a size press liquid to be applied by a size press when producing a base paper for a photographic paper support of the present invention. In general, as a starch-based binder used in a size press liquid, a material made from corn starch is often selected. On the other hand, in comparison with corn starch, rhizome starch tends to exhibit strength in terms of molecular structure and molecular weight. And the surface strength of the base paper surface can be raised by applying the modified starch mainly composed of rhizome starch to a solid of 1.4 to 2.6 g / m ² , and further the rigidity of the whole paper can be raised. It has been found that the hand feeling of the photographic paper support can be improved.

When the solid coating amount of the modified starch mainly composed of rhizome starch is less than 1.4 g / m ² , the surface strength improving effect and the stiffness improving effect are not sufficient. When the solid coating amount of the modified starch mainly composed of rhizome starch exceeds 2.6 g / m ² , the surface strength and rigidity are improved, but the adhesion of the polyolefin resin to the base paper is lowered.

  The rhizome starch in the present invention is starch made from tapioca and potato, and is modified by introducing a functional group into these raw material starch, oxidized starch, acetylated starch, urea phosphated starch・ Modified into hydroxyethyl etherified starch and cationized starch. Examples of methods for applying these modified starches to the base paper surface include application methods such as a size press / gate roll coater, spray coating, and lot metering size press. A press is mentioned.

  Next, the present inventors examined a method for efficiently expressing the size of the base paper. As a result, it was found that the size is improved by blending and adjusting an insoluble alkaline pigment. And it discovered that especially calcium carbonate had a favorable size improvement effect. The inventors have the effect of raising the pH of the alkaline pigment, the pigment and the fine sizing emulsion are easily adsorbed in the papermaking system, and the pigment having a large specific surface area is liable to cause defects during papermaking. In view of these points, it was found that calcium carbonate is an insoluble alkaline substance that adjusts the balance in the papermaking system, has good size development, and has few defects during papermaking.

  And when making the base paper of this invention contain calcium carbonate, it discovered that 0.3 mass% or more and 5.0 mass% or less with respect to a pulp were optimal as a compounding quantity of calcium carbonate.

  When the content of calcium carbonate is less than 0.3% by mass, the pH increase in the system at the time of papermaking is not sufficient, and the effect of improving the size is not sufficient. When the content of calcium carbonate is more than 5.0% by mass, the effect of improving the size property is saturated. Furthermore, the stiffness is lowered.

  The calcium carbonate may be heavy calcium carbonate or light calcium carbonate, but considering the smoothness and whiteness of the base paper, the yield, the wearability of paper machine equipment, the dispersion stability of the calcium carbonate slurry, etc. In this case, light calcium carbonate produced by chemical synthesis is preferred. There is no restriction | limiting in particular regarding the addition order of a calcium carbonate. However, in order for calcium carbonate to be efficiently retained in the paper, calcium carbonate should be added separately near the mixing box and the head box (for example, at the fan pump inlet) or added all at once near the head box. May be.

  In the base paper used in the practice of the present invention, various additives can be incorporated when preparing the paper stock slurry. As sizing agents, in addition to alkyl ketene dimers, fatty acid metal salts or dialkyl ketones, alkenyl or alkyl succinic anhydrides, rosin derivatives, epoxidized higher fatty acid amides described in JP-A-54-147211, JP-A-56 An organic fluoro compound described in JP-A-109343 can also be used in combination. In order to achieve the present invention, the content of the alkyl ketene dimer in the base paper is preferably 0.1 to 0.5% by mass with respect to the pulp.

  The base paper chemicals used in the present invention may contain various water-soluble polymer compounds. The water-soluble polymer compound may contain at least one of polyacrylamide resin, polyamine epichlorohydrin resin, starch, starch derivative, natural polymer compound other than starch, polyvinyl alcohol, and gelatin. Preferably, guar gum and its modified product described in JP-A-63-163358 are even better.

The base paper used in the present invention may further contain various water-soluble inorganic salts. The water-soluble inorganic salt is preferably an inorganic salt containing sodium, calcium, lithium, magnesium, barium, such as sodium chloride, sodium sulfate, sodium phosphate, calcium chloride, lithium chloride, magnesium chloride, magnesium sulfate, barium chloride, etc. Can be mentioned. The content of these water-soluble inorganic salts in the base paper is preferably 0.1 to 0.5 g / m ² . 0.1 g / m ² or more is preferable from the viewpoint of operability such as sufficient antistatic property of the base paper, and 0.5 g / m ² or less is preferable from the viewpoint of suppressing a decrease in strength of the base paper. Although there is no restriction | limiting in particular about the method of containing these water-soluble inorganic salts in a base paper, The method of adding and impregnating to a size press liquid or a tab size liquid is common.

  In the base paper used in the present invention, in addition to those mentioned above, fixing agents such as sulfuric acid band and aluminum chloride, paper strength agents such as melamine resin, urea resin and epoxidized polyamide resin, kaolin, talc, clay, titanium oxide and the like If necessary, additives such as fillers, organic conductive agents, fluorescent brighteners, dyes, pigments, antioxidants and the like are added.

The natural pulp constituting the base paper used in the present invention is not particularly limited as long as it does not practically affect the photographic emulsion and additive chemicals. The basis weight is preferably 50 to 250 g / m ² . Further, from the viewpoint of smoothness of photographic printing paper, surface treatment is performed by applying heat and pressure to the base paper with a machine calendar, a super calendar, or the like.

  A support for photographic paper can be obtained by extrusion-coating a resin such as a polyolefin resin capable of forming a film by a known method on both sides of the base paper produced as described above. As an equipment for extrusion coating, an ordinary polyolefin extruder and laminator are used. Examples of the polyolefin resin include homopolymers of α-olefins such as polyethylene and polypropylene, and various mixtures of these polymers.

  Particularly preferred polyolefins are high density polyethylene, low density polyethylene and mixtures thereof. These polyolefins are not particularly limited in molecular weight as long as they can be extrusion-coated, but polyolefins having a molecular weight in the range of 20,000 to 200,000 are usually used. The thickness of the resin coating layer is not particularly limited and can be determined according to the thickness of a conventional resin coating layer for a photographic paper support, but is usually 15 to 50 μm.

  In the resin layer, known additives such as a white pigment, a color pigment, a fluorescent brightening agent, and an antioxidant can be added. In particular, it is preferable to add a white pigment and a colored pigment in the resin coating layer on the front surface on which the photographic emulsion is applied. The support using the photographic paper base paper produced in the present invention is further coated with a photographic emulsion layer on one side and dried to form a photographic photographic paper. A subcoat layer can be applied on the resin coating layer on the surface side, or a backcoat layer for improving printing writability and antistatic properties can be applied on the resin coating layer on the back surface. Various aspects are possible.

  In the photographic paper support in the present invention, an undercoat layer containing at least gelatin can be coated on the resin surface on the side where the image forming layer is provided. Examples of gelatin used in the undercoat layer include lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, gelatin derivatives such as gelatin reacted with an anhydride of dibasic acid, and the like. In addition, other hydrophilic polymers such as polyvinyl alcohol and starch can be used in combination with gelatin. Further, the pH of the undercoat coating solution is not particularly limited, but is preferably pH 8 or less, more preferably pH 7 or less, from the viewpoint of storage stability.

  A back coat layer is preferably provided on the back resin surface of the photographic paper support in the present invention for the purpose of preventing charging. In the backcoat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a curing agent, a surfactant and the like can be appropriately combined. If the back coat layer contains fine particles such as inorganic or organic pigments, the contact between the plate cylinder and the lithographic printing plate becomes the contact by the convex portions of the fine particles, and the contact area is appropriately reduced. Allow movement and avoid wrinkles.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.

(Base paper manufacturing process)
LBKP pulp was diluted to a pulp solid content of 4% by mass, beaten to a freeness of 300 ml CSF, and then diluted to a pulp solid content of 1% by mass to obtain a pulp slurry. The pulp slurry thus obtained was adjusted to pH 7.5 by adding sodium carbonate, and further, 1.3% by mass of cationized starch with respect to pulp and 0.2% of polyamide polyamine epichlorohydrin resin with respect to pulp. A papermaking raw material was prepared by adding 0.3% by mass of alkyl ketene dimer sizing agent to 0.3% by mass of pulp and 0.2% by mass of epoxidized fatty acid amide to pulp. Paper making was performed so that the basis weight was 170 g / m ² . Subsequently, a surface size press comprising 3.5% by mass of modified starch (“Fibersize382” manufactured by NSC Japan: raw material tapioca starch), 0.5% by mass of NaCl, 0.05% by mass of optical brightener, and 94.55% by mass of water. The liquid was subjected to size press treatment so that it was fed at a wet amount of 40 g / m ² , dried, and then subjected to on-machine calendar treatment to produce a base paper having a thickness of 168 μm.
(Resin coating process)
The surface of the obtained base paper (photographic emulsion coating side) was coated with polyethylene having a density of 0.96 g / cm ³ containing 10% by mass of titanium dioxide to a thickness of 30 μm. Further, the back side of the base paper (the side opposite to the photographic emulsion coating side) was coated with polyethylene having a density of 0.98 g / cm ³ to a thickness of 30 μm to produce a photographic paper support of Example 1.

  A support for photographic printing paper of Example 2 was obtained in the same manner as in Example 1 except that the concentration of the modified starch of Example 1 was changed to 4.5% by mass.

  A photographic paper support of Example 3 was obtained in the same manner as in Example 1 except that the concentration of the modified starch of Example 1 was changed to 5.5% by mass.

  A photographic paper support of Example 4 was obtained in the same manner as in Example 1, except that the concentration of the modified starch of Example 1 was changed to 6.5% by mass.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate ("Tama Pearl TP121" manufactured by Okutama Kogyo) was added so that the ash content in the paper was 0.3% by mass. In the same manner as in Example 1, a photographic paper support of Example 5 was obtained.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate (“Tama Pearl TP121” manufactured by Okutama Kogyo Co., Ltd.) was added so that the ash content in the paper was 0.3% by mass, and the concentration of the modified starch was adjusted. A photographic paper support of Example 6 was obtained in the same manner as in Example 1 except that the content was changed to 4.5% by mass.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate (“Tama Pearl TP121” manufactured by Okutama Kogyo Co., Ltd.) was added so that the ash content in the paper was 0.3% by mass, and the concentration of the modified starch was adjusted. A photographic paper support of Example 7 was obtained in the same manner as in Example 1 except that the content was changed to 5.5% by mass.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate (“Tama Pearl TP121” manufactured by Okutama Kogyo Co., Ltd.) was added so that the ash content in the paper was 1.0% by mass, and the concentration of the modified starch was adjusted. A support for photographic paper of Example 8 was obtained in the same manner as Example 1 except that the content was changed to 5.5% by mass.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate (“Tama Pearl TP121” manufactured by Okutama Kogyo Co., Ltd.) was added so that the ash content in the paper was 5.0% by mass, and the concentration of the modified starch was adjusted. A photographic paper support of Example 9 was obtained in the same manner as in Example 1 except that the content was changed to 5.5% by mass.

  In Example 1, instead of adding sodium carbonate, light calcium carbonate (“Tama Pearl TP121” manufactured by Okutama Kogyo Co., Ltd.) was added so that the ash content in the paper was 6.0% by mass, and the concentration of the modified starch was adjusted. A photographic paper support of Example 10 was obtained in the same manner as in Example 1 except that the content was changed to 5.5% by mass.

(Comparative Example 1)
In Example 1, the modified starch was changed to corn starch-based oxidized starch ("MS3800" manufactured by Nihon Shokuhin Co., Ltd.), and the concentration was changed to 4.5% by mass. A support for photographic paper was obtained.

(Comparative Example 2)
A support for photographic paper of Comparative Example 2 was obtained in the same manner as in Example 1 except that the concentration of the modified starch of Example 1 was changed to 3.0% by mass.

(Comparative Example 3)
A support for photographic printing paper of Comparative Example 3 was obtained in the same manner as in Example 1 except that the concentration of the modified starch of Example 1 was changed to 7.5% by mass.

(Comparative Example 4)
Photographic paper support of Comparative Example 4 except that the modified starch of Example 1 was changed to PVA (“T-330H” manufactured by Toagosei Co., Ltd.) and the concentration was changed to 4.5% by mass. Got.

(Comparative Example 5)
In Example 1, except that the addition amount of the alkyl ketene dimer added to the base paper was changed to 0.1% by mass and the concentration was changed to 4.5% by mass with corn starch, A support for photographic paper of Comparative Example 5 was obtained.

  Table 1 shows the evaluation results of the stiffness and edge penetration of these photographic paper supports. The evaluation method was performed as follows.

<Roll dirt>
The degree of soiling of the paper roll when the base paper of the support of the present invention was laminated was determined visually.
○: Conspicuous dirt is not seen on the surface of the paper roll when operated for 24 hours or more.
Δ: Paper dust accumulated on the surface of the paper roll when operated for 24 hours or more.
Improvement effect is recognized.
X: Accumulation of paper dust is observed on the surface of the paper roll within 24 hours, and defects and molds due to foreign matters are observed in the paper.

<Edge dirt>
Edge contamination of the support is developed by processing the obtained photographic paper support with an automatic processor (manufactured by FC Seisakusho, color roll processor), and processing liquid from the end of the photographic paper support after processing. The penetration depth was measured and judged. In order to maintain an excellent appearance, 0.55 mm or less, more preferably 0.45 mm or less is required.

<Stiffness>
The rigidity of the support was evaluated as follows. It was measured according to JIS-P-8125 (a measure of paper stiffness measured by a Taber stiffness tester) (hereinafter abbreviated as stiffness in the table). In order to obtain a support for photographic printing paper having excellent transportability without trouble in the developing processor and having a hand feeling as photographic paper, at least the Taber stiffness of 16.0 gf · cm or more is required. 17.5 gf · cm or more is preferable.

<Adhesion>
The adhesiveness between the resin layer of the support and the paper substrate was evaluated by peeling the resin layer after heat-treating the support at 55 ° C. for 3 hours and visually observing the peeled surface. The evaluation criteria are good adhesion → ◯, somewhat bad, but improvement effect is recognized → Δ, bad → ×. At the “x” level, it cannot be used practically.

<Result evaluation>
By comparing Example 2 with Comparative Example 1, by applying modified starch made from rhizome starch to the base paper surface, compared to applying modified starch made from corn starch to the base paper surface, the base paper The surface strength was increased, and when the polyolefin resin was processed on the surface of the base paper, the paper roll was less soiled, the rigidity increased at the same starch application level, and a hand feeling was obtained.
By comparing Examples 1 to 4 with Comparative Examples 2 and 3, the modified starch made from the rhizome starch of the present invention as a raw material is made into 1.4 to 2.6 g / m ² on the surface of the base paper, thereby making it a polyolefin resin. It can be seen that the paper roll is less contaminated in the processing step, the adhesiveness between the base paper and the polyolefin resin is good, and the penetration and rigidity are good. When the coating amount of the modified starch made from rhizome starch is less than 1.4 g / m ² , the effect of increasing the surface strength of the base paper surface is not sufficient, and the effect of increasing the rigidity is not observed. Further, when the coating amount of the modified starch using rhizome starch as a raw material is more than 2.6 g / m ² , the surface strength and rigidity are improved, but the adhesion with the polyolefin resin tends to deteriorate. It can be seen.

  By comparing Examples 1 to 3 and Examples 5 to 7, it can be seen that, by blending calcium carbonate at the time of papermaking, size properties are improved and soaking is improved. By comparing Example 2, Example 6 and Examples 8-10, calcium carbonate is blended in 0.3-5.0% by mass base paper as ash, and a size improvement effect is recognized, When the ash content exceeds 5.0% by mass, the size of the base paper is deteriorated. Accordingly, the ash content in the calcium carbonate base paper is preferably 0.3 to 5.0% by mass.

By comparing Example 2 and Comparative Example 4, performance evaluation with a binder other than the starch-based binder can be performed, but in the case of PVA, the adhesiveness with the polyolefin resin is poor. Further, by comparing Example 2 with Comparative Example 1 and Comparative Example 5 to reduce the alkyl ketene dimer of the internal sizing agent, the paper roll stains during lamination of the polyolefin resin are reduced by the internal sizing agent of the base paper. Although it can be improved by reducing the amount of (alkyl ketene dimer), the penetration is also worsened. It can be seen that by using the rhizome starch, it is possible to provide a base paper with good penetration and less paper roll contamination during the lamination of the polyolefin resin.

  The support for photographic paper of the present invention has few defects when processing a polyolefin resin on a base paper, is excellent in the appearance of the surface to be coated, and has a cutting property and a size against penetration of a developer. It can be used as a support for photographic printing paper with excellent quality and hand feeling.

Claims (2)

A polyolefin paper is coated on a base paper coated with 1.4 to 2.6 g / m ^{2 of} a modified starch mainly composed of rhizome starch on the surface of a paper to which at least an alkyl ketene dimer is added as a sizing agent. Support for photographic paper.   2. The support for photographic printing paper according to claim 1, wherein the paper contains 0.3 to 5.0 mass% of calcium carbonate.