JPS61255338A - Photographic support - Google Patents

Abstract

PURPOSE:To enhance writability of a photographic printing paper and its staining resistance by forming a writability-giving layer composed of an inorg. pigment having a number average particle diameter of 0.1-3mum, and contg. <=10wt% particles having a particle diameter of <=3mum, and a colloidal alumina on the reverse side of the photographic printing paper coated with polyolefin. CONSTITUTION:The compsn. of a resin, such as an alpha-olefin homopolymer of polyethylene, polypropylene, or a copolymer of these alpha-olefin, preferably, high- density or low-density polyethylene or their mixture, is used for forming the polyolefin resin coated layer of the photographic printing paper. It is preferred to properly roughen the reverse side of the polyethylene layer to form a matted surface. The inorg. pigment to be added to the writability-giving layer has a number average particle diameter of 0.1-3.0mum, preferably, 0.2-2.0mum, and it contains >=3.0mum diameter particles in an amt. of >=10%. Such a pigment is ebbodied by crystalline silica and synthetic silica and the like.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a polyolefin-coated photographic paper, and more specifically, a writability imparting layer is provided on the back side of the photographic paper to improve writability, etc. This paper relates to improved photographic paper.

(Prior Art) Conventionally, baryta paper has been used as photographic paper, but so-called water-resistant photographic paper, in which both sides of the base paper are coated with polyolefin, has been developed for the purpose of speeding up the development process.
Currently, they account for the majority of them. This water-resistant photographic paper usually has one side (usually titanium oxide (TiOz)
A photographic emulsion layer is coated on the polyolefin layer (containing an inorganic pigment such as ). In this specification, the surface to which the emulsion layer is coated will be referred to as the "front surface", and the opposite surface to which the emulsion layer is not coated will be referred to as the "back surface".

This back side is used for various purposes, such as ballpoint pens,
It is desirable to have writing properties, drawing properties, and printability using fountain pens, pencils, oil-based inks, water-based inks, etc.

However, as mentioned above, since water-resistant photographic paper is coated with polyolefin (most commonly polyethylene), its surface is hydrophobic and non-absorbent. It is difficult to write on it, and it also has drawbacks such as scratches when writing on it, or it disappears or smudges due to slight friction after writing.

Conventionally, methods for imparting writing, drawing, and printability to a polyolefin layer include roughening the surface by sandblasting, embossing, etc., and etching the surface with acid, etc. to make the surface rougher. However, the writability of the resulting polyolefin layer was not fully satisfactory.

Various attempts have been made to improve these drawbacks. That is, in the back polyolefin resin layer, /~4/
- Method of incorporating an inorganic pigment of θμ
! 2r). A method of providing a layer consisting of a water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose and an aqueous silica sol (Special Publication Show≠≠-/≠rye issue), a method of providing a layer consisting of a water-insoluble polymer emulsion such as a polyethylene emulsion and an aqueous silica sol ( Tokukosho! 0-36Jj6! No. 0-36
-745' Hiroshi No. 26) etc. are disclosed.

However, all of these known methods have drawbacks. For example, in the back polyolefin resin layer /-
The method of containing an inorganic pigment of 40 μm is impractical due to quality failures due to cracks in the resin film, and process stains caused by the pigment. In addition, in order to obtain sufficient writability, especially writability with a pencil, in the coating layer of the composition that has been conventionally applied, the coating amount is around 1 kjt/m2, and in some cases, i.
oy/? It has to be produced in a large quantity (FL2 or higher), and is subject to many manufacturing restrictions, such as the drying process. In addition, quality defects include the detachment or elution of these coated layers during the photographic processing process, the detachment of pigments due to slight friction after the development process, and the contamination that will be described later. However, it has not been possible to obtain a product that satisfies either of the characteristics.

(Object of the Invention) Therefore, the object of the present invention is to minimize the amount of coating to provide efficient writability, prevent the coating layer from dissolving or detaching during or after the development process, and provide good stain prevention properties. The object of the present invention is to provide photographic paper having the following properties.

(Structure of the Invention) An object of the present invention is to coat the back side of photographic printing paper in which both sides of the base paper are coated with polyolefin (a) with a number average particle size of 0. /~
3μ, and the content of particles with several particle diameters of 3μ or more is io% by weight.
The following was achieved by a photographic printing paper characterized by having a writability imparting layer comprising the following inorganic pigment and O)):rroid alumina.

The photographic paper according to the present invention will be explained in more detail below.

The photographic paper according to the present invention has a base paper as a support, a polyolefin resin coating layer provided on both sides of the base paper, and a writability imparting layer having writability on the polyolefin resin coating layer on the back side. It has a photographic emulsion layer on top of the polyolefin resin coating layer. The base paper used for the photographic paper according to the present invention is selected from materials commonly used for photographic paper. In other words, natural pulp obtained from softwoods, hardwoods, etc. or synthetic fibers made from polyethylene, polypropylene, etc. are all main raw materials such as 1 lup, and various sizing agents, paper strength agents, fillers, fixing agents, etc. are added as necessary. A thickness of JO to 300μ is usually used.

The polyolefin resin composition forming the polyolefin resin coating layer of the photographic paper according to the present invention preferably includes homopolymers of α-olefins such as polyethylene and polypropylene, or copolymers of these α-olefins. are high density polyethylene, low density polyethylene and mixtures thereof. The thickness of these resin layers is usually /j−jOμ. In addition, in these resin layers,
Pigments, fluorescent brighteners, antioxidants, etc. are added as necessary.

It is desirable that the polyolefin layer on the back side has a matte surface with irregularities of appropriate roughness.

That is, if the back polyolefin layer is not made into a matte surface, when the front polyolefin layer is an fR surface, wrinkles will occur due to poor sliding between the front and back surfaces when winding up the polyolefin coated paper, and the rolled up polyolefin will wrinkle. When the coated paper is fed out to be coated with emulsion, the front and back sides get agitated, making it difficult to peel off, resulting in static, and when the coated paper is fed out after coating with emulsion, the emulsion side and back side are difficult to separate. As a result, many problems tend to occur, such as static marks appearing on the emulsion surface and poor paper alignment due to insufficient slippage between the emulsion surface and the back surface of sheet photographic paper or print sheets after development. Also, from the point of view of addition with a pencil,
It is preferable to use a matte surface. However, if the unevenness is too large, in the case of polyolefin-coated paper whose surface polyolefin layer is a mirror surface, the unevenness will stick to the surface when it is rolled up, and the gloss of the surface polyolefin layer, which is a mirror surface, will decrease. The surface roughness of the back polyolefin layer is such that the centerline average roughness Ra defined by JISBO6oi is 1. It is desirable that it be below O.

The inorganic pigment contained in the writability imparting layer of the photographic paper according to the present invention has a number average particle diameter of o, i to 3.0μ, preferably a number average particle diameter of 0.2 to co, Oμ, and The content of particles having a particle diameter of 3 μ or more is io% or less. Furthermore, it is preferable that the content of particles having a particle diameter of Jμ or more is 1ri8 or less. If you use particles with an average particle size smaller than O0lμ, the writing ability, especially when using a pencil, will drop sharply, and if you use particles with an average particle size larger than J or Oμ, it will give a grainy feel and make printing difficult. This has the disadvantage that it separates from the coating layer during or after the paper development process. Therefore, if the content of particles with a particle size of 3μ or more exceeds 10%, the above disadvantages become noticeable.
Significantly reduce product value. In addition, particles with a particle diameter of jμ or more may damage the surface of the support or the surface of photographic paper made by coating the entire emulsion thereon, so it is better to have as few as possible, and the content should be less than flathead. It is desirable that Most preferably, it does not contain particles with an average particle diameter of 3 μm or more.

When the oil absorbency exceeds ioo/100f, there is a drawback that the oil-based ink bleeds more frequently.

Specific examples of such pigments include crystalline silica and synthetic alumina silica.

The colloidal alumina used in the present invention is feather-like alumina with an average size of approximately 10 mm in diameter and approximately 100 mm in length, and is sold under the trade name "Alumina Sol" by Nichiryo Kagaku. Regarding the manufacturing method and properties of the monomer, please refer to Tokuko Showa 3 Tar, 20/YoO1.
It is described in detail in Tokko Akihiro 0-/Hirokota λ and Tokko Akihiro/-J-70, and its application to photographic paper is described in Tokko Akihiro jλ-1ro2o.

Further, the effects of the present invention are more significantly exhibited when the coating layer on the back side of the photographic paper according to the present invention contains colloidal silica.

That is, when colloidal silica is added to the back coating layer containing an inorganic pigment and colloidal alumina, it reduces bleeding when written with a permanent marker and has good stain prevention properties as described below.

That is, in recent years, development processing systems for silver halide color photographic materials have become continuous replenishment systems or continuous recycling systems for the purpose of cost reduction. Therefore, in color photographic processing solutions such as developers and bleach-fixers,
Contaminants consisting of oxidation products and oxidative polymerization products such as developing agents, development accelerators, organic compounds eluted from the silver halide color photographic material into the processing solution accumulate and thus reduce the hydrophobicity of the support of the color photographic material. These contaminants tend to adhere to surfaces, especially the hydrophobic surface opposite to which the emulsion layer is applied. However, the photographic paper according to the present invention does not have such contaminants attached, or even if it does, the contaminants are very slight. That is, it has good anti-pollution properties.

Colloidal silica has a particle size of 10 mm to λQ
A colloidal solution in which millimicron ultrafine silicic acid anhydride particles are dispersed in water, ``Cyton'' by Monsando, USA, ``Ludox'' by DuPont, ``Nalcog'' by Nalco Chemical, and ``Snow'' by Nichichi Kagaku. It is sold under product names such as ``Tex''.

The ratio of colloidal alumina and colloidal silica (solid content weight ratio) is colloidal alumina/colloidal silica =
Used between /10 and l/4c. When colloidal silica is used in a ratio higher than this, a problem arises in that the colloidal silica falls off from the polyolefin layer.

The ratio of the total coating amount of colloidal alumina and colloidal silica to the coating amount of inorganic pigment is 10/l ~ / 0/J O
used between. If the amount of inorganic pigment is too small compared to the total amount of colloidal alumina and colloidal silica, pencil writability will be poor, and if it is too large in the margin, there will be a problem that the inorganic pigment will fall off from the coating layer.

The coating amount of the writability imparting layer of the present invention is o, 0 as solid content.
/f/m2 to 1. Of/r! Preferably between L2.

If the coating amount is less than 0,0/t/m2, writing with a pencil will be poor.Also, i,of/7FL2
On the contrary, even if the coating amount is larger, the writing performance and antistatic performance remain the same. A problem arises in that the coating layer is more likely to separate than the polyolefin layer, which is undesirable.

The coating liquid used when coating the writability imparting layer of the present invention on the polyolefin layer is water-based, but in order to improve coating properties, alcohols such as ethyl alcohol and methyl alcohol, acetone, methyl ethyl ketone, etc. It is possible to use these solvents together.

(9) Various resins, dyes, surfactants, etc. may be added to the above-mentioned coating liquid for the purpose of improving the coefficient of friction, color, etc.

The coating method is generally well-known, such as dip coating, air knife coating, curtain coating, roller coating, doctor coating, wire barcoding, slide coating, gravure coating, etc. I can do it. Note that before performing these coatings, it is desirable to activate the surface of the polyolefin layer to be coated by a known method. As the method of activation treatment, etching treatment with acid, flame treatment with gas burner, corona discharge treatment, glow discharge treatment, etc. are used.

(Examples of the Invention) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples.

Example 1 Base paper with basis weight / I Ot / m2 is processed at 1 OTrL per minute
The back surface was melt-extruded and coated with a high-density polyethylene (density O1bo, MI=/3) T-resin thickness 30μm using a melt extruder, and a matte surface with a center line average roughness Ra of O1tμ. A resin layer was formed.

Next, titanium oxide is applied to the surface of the base paper using a melt extruder.
Low density polyethylene (density Q,
23, melt extrusion coating on MI = 71' with a resin thickness of 30 fi @ to form a glossy resin layer.

Next, after corona treatment of the surface of the back resin layer, a coating solution of the formulation listed in Table 1 was wet applied by bar coating, J,! f
/m2 was coated and dried to produce a photographic support of &/, &l.

After corona discharge treatment is applied to the polyethylene resin layer on the surface of the polyethylene-coated paper coated with these back coats,
A blue-sensitive silver chlorobromide gelatin emulsion layer containing a yellow coupler and an intermediate layer adjacent to the support, a green-sensitive silver chlorobromide gelatin emulsion layer containing a magenta coupler and an ultraviolet absorbing layer containing an ultraviolet absorber, and a cyan coupler. A red-sensitive silver chlorobromide gelatin emulsion layer containing a red-sensitive silver chlorobromide gelatin emulsion layer and its protective layer were coated and dried using an extrusion method to prepare a multilayer silver halide color photographic paper.

Evaluation of the pencil retouchability of the back coat layer, clouding of the surface of the photographic paper, and anti-staining property on the back was indicated by f: O mark (good) and × mark (unusable). The evaluation method is as follows.

Evaluation of pencil rewriting properties of back coat layer> Writing was performed using an HB lead line, and the entire state of the writing was observed and evaluated.

Evaluation of haze on the surface of photographic paper> A sample of the photographic paper made as described above was prepared and rolled at a tension of 20 to 9 per width/rlL, under an environment of 1fiO'C, 10ToRH. 4 tons
After leaving it for t hours, take it out and unwind it. Visually judge the degree of clouding on the surface of the photographic paper due to transfer to the surface of the backing layer.

Evaluation of the back stain prevention performance of the back coat layer> Over time, brown stains formed in the color developing solution and adhered to the heat exchanger were developed using a roll-conveying processor (JO''C, 3 minutes 30 seconds). →Bleach-fixing (JO
'C,/min J 0 seconds) - + water washing (J O'C% 3 minutes) →
After the drying process (to °C, 2o seconds), when the photographic paper is developed, the back side of the photographic paper is pressed with a roll in a color developing solution, and a blackish brown stain is formed on the roll. After the transfer, the extent to which the back side of the photographic paper was stained was observed and determined.

The results of the evaluation are shown in Table 2.

Table 2 As can be seen from Table 2, the photographic papers (Mus 3 to 6) having the back coat layer of the present invention all have good lead retouchability and back stain prevention performance, and the coating layer This is a good silver halide color photographic paper with no transfer to the surface and no clouding on the surface of the photographic paper.

Patent applicant Fuji Photo Film Co., Ltd. Procedural amendment 1, Description of case 1985 Patent Application No. F7/20 2, Title of invention Photographic support 14. ”/.

Address: 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture
Name (520) Fuji Photo Film Co., Ltd. Contact information 10
6 2-26-30 Nishi-Azabu, Minato-ku, Tokyo Not yet amended Subject of the amendment The "Detailed Description of the Invention" column of the specification & contents of the amendment The specification will be amended as follows.

l)≠page/! row "Matan" "problem" and correct it.

2)! page μth row rJIsBo, <θ/” "J Engineering 5BO601" and correct it.

J) Page r, line II "chi" "weight%" and correct it.

4t), rjj/λth row "chi" "weight%" and correct it.

, t) Page r, line 1 "chi" "1 heavy" and correct it.

6) / 3rd line of page 1 "flathead" "2% by weight" and correct it.

7) //Page 3rd line "Super crying child" "Ultrafine particles" and correct it.

r) on page 11 "Full text of Table 1" "Notification of 'Attachment'" and correct it.

Claims (5)

[Claims] (1) On the back side of a photographic support in which both sides of base paper are coated with polyolefin, (a) the content of particles with a number average particle size of 0.1 to 3.0 μ and a particle size of 3 μ or more is 10% by weight or less; 1. A photographic support coated with a coating liquid containing an inorganic pigment and (b) colloidal alumina. (2) The polyolefin coated on the back surface of the photographic support is matted, and the center line average roughness (Ra) of the back surface is
1. The photographic support according to claim 1, wherein: 1μ or less. (3) The photographic support according to claim 1, wherein the inorganic pigment has an oil absorption of 100 CC/100 g or less. (4) The photographic support according to claim 1, wherein the coating liquid contains colloidal silica. (5) The amount of coating liquid applied (weight after drying) is 0.01g/m^2
1. The photographic support according to claim 1, which has a density of 1.0 g/m^2 to 1.0 g/m^2.