JP2895294B2 - Photographic support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the adhesiveness between a polyolefin resin-coated support on which a photographic emulsion is coated and an undercoat layer.
The present invention relates to a polyolefin resin-coated photographic support having improved adhesion to a photographic emulsion and coatability of the photographic emulsion. More specifically, the present invention relates to a polyolefin resin-coated photographic support subbed with a coating solution containing gelatin.

[0002]

2. Description of the Related Art A hydrophobic support of a polyolefin resin-coated paper has been well known as a support for silver halide photography. In particular, the photographic paper support, instead baryta paper which have been used traditionally, has come to be found using a number polyolefin resin-coated paper. The reason for this is that the processing liquid does not easily penetrate the paper layer during the development and fixing of photographic printing paper compared to baryta paper because the polyolefin resin-coated paper as the photographic support is hydrophobic, and is therefore washed with water. This is because there is an advantage that processing time such as drying and the like is reduced.

However, such a hydrophobic support cannot be used as it is to coat an aqueous silver halide photographic emulsion. As a countermeasure, flame treatment, corona discharge treatment, undercoating treatment, etc. are generally known as activation of the hydrophobic support surface, but the flame treatment is inconvenient in handling control, and the corona treatment takes time after treatment. Even when the emulsion is coated on a photographic support whose surface has reduced water wettability and has been attenuated over time, the adhesion between the emulsion layer and the polyolefin resin-coated surface of the support is reduced, and sufficient adhesion to an emulsion film cannot be obtained.

Accordingly, a latex emulsion, a water-soluble synthetic resin, gelatin and a mixture thereof, which have an affinity for a photographic support which has been corona-discharged before the surface water wettability after corona discharge treatment is reduced, are reduced. Even if the emulsion is coated after a long time lapse, the coating property of the emulsion film is not reduced. A gelatin composition is generally used as an undercoat layer provided on a polyolefin resin-coated support in advance.

As a prior art as a means of improvement, according to Japanese Patent Application Laid-Open No. Sho 59-31946, the content of calcium ion (Ca ⁺⁺ ) in gelatin is 200
For the gelatin-containing photographic coating solution with the following gelatin 0 ppm, by the coating amount 0.02g / m ² ~0.5g / m ² of disclosure be provided gelatin subbing layer in JP-A-62-35244 Publication However, it is not possible to provide an undercoat layer having good adhesion of the undercoat layer, uneven coating of the undercoat layer, and good adhesion of the emulsion film.

[0006]

As described above, the object of the present invention is to provide a photographic support provided with an undercoat layer having good adhesion of the undercoat layer, uneven coating of the undercoat layer, and good adhesion of the emulsion film. .

[0007]

The present inventors Means for Solving the Problems], the polyolefin resin coating is provided on both sides of the paper substrate in order to solve the problems described above, gelatin polyolefin resin-coated surface on the side where photographic emulsions will be applied In a photographic support provided with an undercoat layer, the undercoat layer has a jelly strength of 200 g to 2 g.
60 g and the content of calcium ion (Ca ⁺⁺ ) in the gelatin is 2000 ppm to 4000 with respect to the dry gelatin.
It found to be achieved by the use of ppm der Ruze Lachin.

[0008] The paper substrate used in the present invention comprises natural pulp, synthetic pulp alone or in a mixture, internal size, surface size, optical brightener, etc., and has a basis weight of 80 g / m ² to 2 g.
Density of 0.90 g / cm ^{3 to} 1.20 g / c at 00 g / m ²
m is ^3. The polyolefin resin used for the polyolefin resin coating layer is high-density polyethylene (HDPE),
Low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), carboxy-modified polyethylene,
A single or a mixture selected from polyolefins such as polypropylene (PP). Further, the polyolefin resin layer contains a white pigment, a color pigment, a fluorescent whitening agent, an antioxidant, a higher fatty acid soap and the like. The resin to be used is applied by a general method such as extrusion coating or solvent coating. Depending on the resin, treatment such as electron beam curing may be performed.

The gelatin used in the present invention includes an acid-treated gelatin, an alkali-treated gelatin, a modified gelatin, an enzyme-treated gelatin and the like, and an acid-treated gelatin is preferred. The jelly strength of the gelatin used in the present invention is preferably in the range of 200 g to 260 g. If the jelly strength is lower than 200 g, the strength of the gelatin layer does not increase, and the adhesiveness of the undercoat layer and the film sticking property after coating the emulsion are poor, so that the object cannot be achieved. When the jelly strength is higher than 260 g, the coating unevenness of the undercoat layer becomes worse, the object cannot be achieved, the price becomes high, and it is not economical. Calcium ion of gelatin (C
a ⁺⁺ ) content from 2000 ppm to dry gelatin
It is preferably in the range of 4000 ppm. If the content of calcium ion (Ca ⁺⁺ ) is lower than 2000 ppm, the adhesion of the undercoat layer is inferior, so that the purpose cannot be achieved. If the content of calcium ion (Ca ⁺⁺ ) is more than 4000 ppm, the film-coating property after the emulsion coating is poor, and the object cannot be achieved.

The undercoat layer of the present invention may contain a surfactant, a preservative, a pH adjuster, a pH buffer, a hardener for gelatin, an alcohol, and the like as necessary. The surfactant is preferably added with an anionic surfactant in order to improve the coating property of the emulsion. The coating amount of the gelatin subbing layer is ^{0.02g / m 2 ~0.1g / m 2} , preferably from ^{0.03g / m 2 ~0.07g / m 2} . If the coating amount is less than 0.02 g / m ² , the adhesion of the undercoat layer and the film-forming property after the emulsion coating are poor, and the object cannot be achieved. If the coating amount is more than 0.1 g / m ² , the coating unevenness of the undercoat layer is inferior and the object cannot be achieved. The water wettability of the resin-coated surface before providing the undercoat layer must be 45 dynes / cm or more, and is preferably 45 dynes / cm to 60 dynes / c.
m. If it is lower than 45 dynes / cm, the adhesion of the undercoat layer is weak and insufficient. If it is higher than 60 dynes / cm, corona pinholes are generated on the resin-coated surface, and a stable product cannot be obtained.

The photographic support of the present invention can be provided with various silver halide photographic emulsion layers. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. A multilayer silver halide photographic layer can be provided by incorporating a color coupler into the silver halide photographic emulsion layer. As binders for those silver halide emulsion layers, polyvinylpyrrolidone,
Hydrophilic polymer substances such as polyvinyl alcohol and polysaccharide sulfate compounds can be used. The above silver halide emulsion layer contains a sensitizing dye, a chemical sensitizer, an antifoggant, a hardener, a coating aid, a stain inhibitor, a development accelerator, an ultraviolet absorber, a fluorescent brightener, a sharpness Improver, antistatic agent, P
Various additives such as an H regulator can be contained.

The coating method according to the present invention can be applied by a generally well-known coating method, for example, a dip coating method, an air knife coating method, a curtain coating method, a gravure coating method, or the like. The liquid thus applied is subsequently dried in a drying step, the condition being 40 ° C to 13 ° C.
The temperature and time can be appropriately determined within the range of 2 seconds to 3 minutes at 0 ° C.

[0013]

In order to improve the photographic support provided with an undercoat layer having good adhesion to the undercoat layer, uneven coating of the undercoat layer, and good adhesion to the emulsion film, the jelly strength of gelatin in the undercoat layer should be 200 g to 2 g.
60 g and the content of calcium ion (Ca ⁺⁺ ) in the gelatin is 2000 ppm to 4000 with respect to the dry gelatin.
By using gelatin at ppm, the hydrophilicity of the interface between the polyolefin and the emulsion is improved, which affects the adhesiveness of the undercoat layer, coating unevenness of the undercoat layer, and the property of attaching an emulsion film.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below. Note that the present invention is not limited to the embodiments.

Example 1 As a polyolefin resin layer on the side where a subbing layer of a paper substrate having a basis weight of 180 g / m ² is provided, 23 g / m ^{2 of} LDPE containing titanium oxide and zinc stearate is applied and a resin layer on the opposite side is provided. LDPE and HDPE in a 50/50 ratio of 20
g / m ² . Further, the polyethylene surface on the side on which the undercoat layer is provided is subjected to corona discharge treatment to prepare a photographic support having a water wettability of 50 dynes / cm. Thereafter, calcium ion (Ca ⁺⁺ ) 2000 p with a jelly strength of 200 g is prepared.
After dissolving in a 1% aqueous solution of gelatin containing pm, a hardener and an activator were added to obtain a coating solution. The gelatin aqueous solution was applied with an air knife coater so that the gelatin became 0.05 g / m ² and dried at 120 ° C. to form an undercoat layer to prepare a photographic support. The emulsion was run at a speed of / min, and a normal monochrome emulsion and a color emulsion were coated thereon and evaluated. The results are summarized in Table 1.

[0016]

[Table 1]

Example 2 An undercoat layer was prepared in the same manner as in Example 1 except that the content of calcium ion (Ca ⁺⁺ ) in gelatin was changed to 4000 ppm using the photographic support of Example 1, and the same evaluation was performed. . The results are summarized in Table 1.

Example 3 An undercoat layer was provided in the same manner as in Example 1 except that the amount of gelatin applied was changed to 0.02 g / m ² using the photographic support of Example 1 and an aqueous solution of gelatin. An evaluation was performed. The results are summarized in Table 1.

Example 4 An undercoat layer was provided in the same manner as in Example 1 except that the photographic support and the aqueous solution of gelatin in Example 1 were used and the coating amount of gelatin was changed to 0.10 g / m ² . An evaluation was performed. The results are summarized in Table 1.

Example 5 An undercoat layer was prepared in the same manner as in Example 1 except that the jelly strength of gelatin was changed to 260 g using the photographic support of Example 1, and the same evaluation was performed. The results are summarized in Table 1.

Example 6 Using the photographic support of Example 1, the gelatin had a jelly strength of 260 g and a calcium ion (Ca ⁺⁺ ) content of 400.
An undercoat layer similar to that of Example 1 was provided except that the amount was changed to 0 ppm, and the same evaluation was performed. The results are summarized in Table 1.

Comparative Example 1 An undercoat layer similar to that of Example 1 was provided, except that the jelly strength of gelatin was changed to 190 g using the photographic support of Example 1, and the same evaluation was performed. The results are summarized in Table 1.

COMPARATIVE EXAMPLE 2 An undercoat layer was prepared in the same manner as in Example 1 except that the jelly strength of gelatin was changed to 280 g using the photographic support of Example 1, and the same evaluation was performed. The results are summarized in Table 1.

Comparative Example 3 An undercoat layer similar to that of Example 1 was used, except that the calcium ion (Ca ⁺⁺ ) content of gelatin was changed to 1500 ppm using the photographic support of Example 1, and the same evaluation was performed. . The results are summarized in Table 1.

Comparative Example 4 An undercoat layer similar to that of Example 1 was provided, except that the calcium ion (Ca ⁺⁺ ) content of gelatin was changed to 4200 ppm using the photographic support of Example 1, and the same evaluation was performed. . The results are summarized in Table 1.

[0019]

As described above, by carrying out the present invention, it is possible to obtain a photographic support excellent in adhesion of the undercoat layer, coating unevenness of the undercoat layer, emulsion film attaching properties and photographic properties.

Claims (1)

(57) [Claims] In a photographic support having a polyolefin resin coating layer provided on both sides of a paper substrate and a gelatin subbing layer provided on the polyolefin resin coating side on which the photographic emulsion is coated, jelly is added to the subbing layer. Strength (according to the jelly strength measurement method of the photographic gelatin test method) is 200 g to 26 g
A photographic support comprising 0 g of gelatin having a calcium ion content of 2000 to 4000 ppm based on dry gelatin.