JPH03171042A - Paper for photographic support - Google Patents

Abstract

PURPOSE:To enhance rigidity, tensile strength, photographic performance, and smoothness by using a cationized modified starch having a substitution degree of 0.01 - 0.035 as an internal size and/or a surface size. CONSTITUTION:The cationized modified starch of 0.01 - 0.035 substitution degree is used as the internal size and/or the surface size. It is prepared by modifying starch by using a cationizing agent of 3-chloro-2- hydroxypropyltrimethylammonium chloride at a reaction temperature of 42 - 48 deg.C, preferably 46 - 48 deg.C, under pH 11 - 12, thus permitting paper strength, mainly such as rigidity, transportability, surface smoothness, and photographic performance can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a photographic support that is strong, has high smoothness, and is suitable for photography.

(B) Prior Art When a photographic support is used as a photographic paper, it is required to have strong strength for transportation within a processor during development. For this reason, it is currently known that in order to obtain high strength, a large amount of strength agents such as cationic polymer electrolytes and anionic polymer electrolytes are added internally or sized on the surface. However, when a large amount of cationic polymer electrolyte is added internally, it may not be possible to obtain the photographic properties essential for photographic paper, as well as a uniformly smooth texture and surface grain, and dehydration on the wire may be poor, resulting in poor drying. There are disadvantages such as it takes time and the speed of papermaking cannot be increased. Further, adding a large amount of strength agent such as cationized starch internally or sizing the surface increases the cost, which is disadvantageous.

In particular, with regard to photographic properties, if a cationized modified starch with a high degree of substitution or a large amount of cationized modified starch is used for the surface size, photographic fog will occur.

JP-A No. 60-185894 discloses that an anion is added to neutral paper to which a tertiary amine starch derivative with a degree of substitution of 0.035 to 0.070 and an organic ketene dimer are internally added in order to strengthen paper strength. A method for producing acid-free paper is disclosed in which the surface is sized using an aqueous solution of a polystyrene-acrylic copolymer. No disclosure is made regarding photo suitability.

JP-A-52-65423 describes a photographic paper using a cationic polymer electrolyte and an anionic substance sufficient to neutralize it. Japanese Patent Publication No. 57-157240
Although the publication discloses a support for photographic paper using a combination of anionic polyacrylamide and cationic starch, there is no description of the degree of substitution of cationization, and the purpose of the invention is also to improve the strength, smoothness, and smoothness of photographic paper. There is no description that satisfies photographic properties at the same time.

(C) Problems to be Solved by the Invention It is an object of the present invention to have a strength that can prevent paper breakage in a processor without increasing the amount of internal addition and/or the amount of surface size of cationized modified starch. The object of the present invention is to provide a photographic support paper which has smoothness suitable for photographic paper and has good photographic properties.

(D) Means for solving the problem, that is, the present invention improves the strength of photographic support paper without increasing the amount of internal addition of cationized modified starch and/or the amount of surface size, and improves smoothness and photographic properties. In order to obtain a good photographic support paper, the degree of substitution of cationization should be 0.01 or more.
Internally added cationized modified starch having a molecular weight of less than 035 and/
or photographic support paper used as a surface sizing agent.

A further cationic modifier for starch is 3-chloro2-hydroxytrimethylammonium chloride.

In addition, the reaction temperature in cationization modification is 42 to 48°C.
More preferably, the temperature is 46-48°C, and the reaction pH is 11-48°C.
This is a photographic support paper using a cationized modified starch modified with No. 12. The amount added to the pulp is 0.
5-10% photographic support paper.

The present invention will be described in detail above.

The degree of substitution in the cationized modified starch in the present invention is preferably 0.01 or more and less than 0.035. Substitution degree is 0
．． If it is less than 01, the adsorption rate of the cationically modified cationized starch to the pulp will be poor, and when other anionic chemicals are used, the adsorption to the pulp will also be poor. In order to increase the degree of substitution to 0.035 or more, it is necessary to increase the amount of cationizing agent added in the cationization modification reaction, but the degree of substitution does not increase even though the amount of cationizing agent is increased, and free cationizing agent is They become impurities, adversely affecting photographic properties, and it may not be possible to obtain a cationized modified starch that meets the purpose of the present invention.

In addition, when added to paper, if the degree of substitution is 0.035 or more, the strength of the resulting photographic support paper will not be much different and it will not be very effective, and water drainage in the wire parts of the paper machine will be poor, resulting in photographic printing paper. The required surface smoothness is reduced.

The cationic modifier for starch is preferably 3-chloro●2-hydroxypropyltrimethylammonium chloride, which is a quaternary ammonium salt derivative. When looking at the degree of substitution of the cationizing agent, it is better to use a tertiary amine to obtain a higher degree of substitution with a small amount, but tertiary amines are expensive to produce, and when looking at the degree of substitution and production cost as a whole, , 3-chloro-2hydroxypropyltrimethylammonium chloride is preferred.

The reaction temperature in cationization modification is preferably 42 to 48°C, more preferably 46 to 48°C. If the reaction temperature is lower than 42°C, the reaction time will be too long, which is disadvantageous. Further, at temperatures higher than 48° C., the starch gelatinizes and the gelatinized portion is more easily cationized, so that cationization is not uniformly performed.

The reaction pH is preferably in the range of 11-12. If the pH is lower than 11, the cationizing agent will not be activated (eboxidized) and the reaction will not proceed smoothly. Furthermore, even if the pH is raised above 12, the activation of the cationizing agent does not change much, so there is no need to raise the pH above 12.

The amount of cationized modified starch added to the bulk is 0.
5% to 10% is preferred. More preferably 1.0% to 6
．． It is 5%. If the amount added is lower than 0.5%, the required tensile strength and stiffness cannot be obtained.

If it exceeds 10%, strong strength can be obtained, but dewatering on the wire becomes poor, the amount of water squeezed out in the press part increases, and sufficient smoothness for photographic paper is lost. As a result, the papermaking speed decreases. In addition, the wire and press dryer become dirty, which causes defects in the base paper (foreign objects, molds).

As the photographic support paper in the present invention, natural pulp paper whose main component is wood pulp such as softwood pulp, hardwood pulp, or softwood hardwood mixed pulp is advantageously used.

In addition to the cationized modified starch according to the present invention, internal sizing agents such as soap and alkyl ketene dimer, which are generally used in paper manufacturing, may be added to the base paper mainly composed of natural pulp, which is advantageously used in carrying out the present invention. , fixing agents such as sulfuric acid band, aluminum chloride, polyamide boriamine chlorohydrin resin, paper strength agents such as melamine resin, urea resin, eboxidized polyamide resin, polyacrylamide resin, titanium oxide, kaolin, clay, calcium carbonate. Additives such as fillers such as, inorganic and organic conductive agents, optical brighteners, dyes, and pigments are blended.

In addition, as a surface sizing agent, in addition to the cationized modified starch according to the present invention, the additives used as the internal sizing agents described above can be used, such as casein, gelatin, Bobal, modified Bobal, SBR, NBR, etc. Latex can also be used. Among these, Poval or modified Boval, alone or in combination with the cationic modification according to the present invention, exhibits the most surface size effect as the one that meets the purpose of the present invention.

There is no particular restriction on the thickness of the photographic support paper of the present invention, but it is preferable to use paper with good smoothness, such as by compressing the paper by applying pressure in a calendar after making the paper, and its basis weight is 40 g/d~ 250g/rrf is preferred.

The photographic support paper produced according to the present invention is produced by a so-called extrusion coating method in which heated and molten resin is cast and coated.

The coating resin is preferably a polyolefin resin, and the polyolefin resin is a homopolymer such as low density polyethylene, high density polyethylene, polypropylene, polybutene, polypentene, or a copolymer consisting of two or more olefins such as ethylene and propylene copolymers. Linear low-density polyethylene, which is a copolymer of ethylene and α-olefin, and mixtures thereof, and those having various densities and melt indexes can be used alone or in combination. In the present invention, it is preferable to use low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene copolymers, etc. alone or in combination.

In addition, the coating resin in the present invention contains white pigments such as titanium oxide, zinc oxide, talc, calcium carbonate, etc.
Fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate,
Fatty acid metal salts such as zinc valmitate, zinc myristate, and calcium valmitate; various antioxidants such as hindered phenol, hindered amine, phosphorus type, and sulfur type;
Various additives such as blue pigments and dyes such as cobalt blue, ultramarine, and cerulean-proof thalocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet, and manganese violet, optical brighteners, and ultraviolet absorbers are appropriately combined. It is preferable to add

(E) Degree of action substitution 0. By adding and/or surface sizing starch that has been cationically modified with O1 or more and less than 0.035, it can be uniformly mixed with pulp fibers and
Because it is strongly adsorbed and retained, the paper strength, mainly stiffness, is enhanced compared to the normal amount of starch added, which prevents folding in the processor.
Wrinkles are eliminated and transportability is improved. Furthermore, a photographic support paper having surface smoothness and suitable for photographic properties can be produced.

(F) Example Specific examples and comparative examples of the present invention will be described below.

Example 1 (Experiment shame 2. 3. 4, 6. 8
) and Comparative Example 1 (Experimental Magnetism 1. 5. 7. 9) 40°C hot water was placed in a constant temperature bath, and 2.0% of anhydrous sodium sulfate was added to the cornstarch as a gelatinization inhibitor.
As a reaction initiator, sodium hydroxide was added at 1.7% to corn starch, and the cationizing agent listed in Table 1 was added to the degree of cationization listed in Table 1, and corn starch (low cons; manufactured by Nihon Shokuhin Kako Co., Ltd.) was added. 30% based on water was added, and sodium hydroxide was added again as a reaction initiator and pH adjuster to adjust the pH to 11.

This was heated to 47°C and reacted for 5 hours.

After the reaction was completed, sulfuric acid was added as a reaction terminator and neutralizing agent. Add 40℃ hot water to the slurry obtained from the above reaction, adjust the concentration to 8%, and cook in a cooker (manufactured by Oji National).
Gelatinization was carried out using a water bottle, and hot water was added to prepare an internal additive of cationized modified starch at a concentration of 3%.

On the other hand, 1= of hardwood bleached kraft pulp (LBKP) and softwood bleached sulfite pulp (NBSP)
1 mixture with Canadian Standard Freeness
This was combined with 0.5% by weight of alkyl ketene dimer (Acopel 24, manufactured by DHC Co., Ltd.) as a sizing agent, based on the pulp, and polyacrylamide (Star Gum Yaichi 15, manufactured by Seiko Kagaku Co., Ltd.) as a strength agent, based on the pulp. l.
0% by weight, and 2.0% solid content was added to a pulp slurry containing 0.5% by weight of polyamide epichlorohydrin (Evinox P-11301 manufactured by DHC) based on the pulp.

This was diluted to form a 1% slurry. This slurry was made into paper using a Fourdrinier paper machine to have a basis weight of 170 g/nf, and a surface size of 2 g/ai solids was made with a 1:5 mixture of cationized modified starch and modified poval. This paper was used as a photographic support paper to serve as a base paper.

Density 0.918g on the surface of paper-made photographic support paper
/an'' per 100% by weight of low density polyethylene
A polyethylene resin composition in which 0% by weight of anatase-type titanium oxide was uniformly dispersed was melted at 320°C, and a thickness of 30μ was obtained.
Extrusion coated to make it look like this. Also, the other side (back side) has a density of 0. 9 6 2 g/an”
of high density polyethylene and density 0. 9 1 8 g/
An' low density polyethylene resin was kneaded in a ratio of 50:50, similarly melted at 320° C., and extrusion coated to a thickness of 30 μm to prepare a photographic support. The stiffness of the prepared photographic support was measured using a Taber stiffness measuring device, and the strength was measured using a tensile measuring device. Furthermore, a color silver halide emulsion was coated on the surface of this photographic support to prepare a color photographic paper, and the photographic properties such as center and capri and the smoothness of the emulsion layer were evaluated. The smoothness evaluation was divided into four stages. ◎: Excellent, ○: Improvement is recognized, △: No problem in practical use, ×: Cannot be used.

Table 1 shows the evaluation results.

(Left below) Table 1 NT21S; 3-chloro-2-hydroxypropyltrimethylammonium chloride (quaternary ammonium salt) DEAC manufactured by Mitsubishi Gas Chemical ■. Made by Diamond Chemical
Diethylaminoethyl chloride (tertiary amine) Example 2 Cationized modified starch was obtained according to Experiment 4 of Example 1 except for the conditions listed in Table 2 in Example 1.

The amount of cationizing agent NT-213 added was 4.0% based on cornstarch. The results are shown in Table 2.

Table-2 Fish 7 was partially gelatinized and cationization was uneven.

Example 3 and Comparative Example 2 (Experiment Nα6) Based on Experiment Nα3 of Example 1, photographic support papers shown in Table 3 were obtained by varying the amount of cationized modified starch added per pulp.

Furthermore, evaluation as a photographic paper described in Example 1 was conducted and the results are shown in Table 3.

(Margin below) Table 3 (G) Effect of the invention In the photographic support paper of the present invention, the degree of substitution is 0.01.
By using cationized modified starch with a particle size of less than 0.035 as an internal addition and/or as a surface size, the rigidity and tensile strength of the photographic support can be improved, and the fog etc. required for photographic paper can be improved. Smoothness was also obtained without impairing photographic properties.

Claims (1)

[Scope of Claims] 1. A photographic support paper internally added and/or surface-sized using a cationized modified starch having a degree of substitution of 0.01 or more and less than 0.035. 2. 0.5% cationized modified starch based on pulp
A photographic support paper according to claim 1, comprising ~10%. 3. The photographic support paper according to claim 1, which has a surface size including poval. 4. The photographic support paper according to claim 1, wherein the cationically modified starch is cationically modified using 3-chloro.2-hydroxypropyltrimethylammonium chloride as a cationizing agent. 5. Substitution reaction temperature is 42-48°C and pH is 11-48°C.
The photographic support paper according to claim 1, 2 or 4, which is a cationized modified starch substituted with 12.