JP2688870B2 - Photographic paper support - Google Patents

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, and more particularly to a photographic printing paper support excellent in glossiness and resolution response.

[0002]

2. Description of the Related Art Conventionally, in photographic printing paper, in order to improve water resistance and light reflection efficiency, a surface of the base paper on which the emulsion is coated is coated with a polyolefin resin layer such as polyethylene containing titanium oxide. ing. in this case,
Polyolefin is excellent in flexibility and processability when used as a photographic printing paper, but is not sufficiently glossy and has a limit in response of photographic resolution. However, in the photographic printing paper having a glossy surface, which is most popularly used at present, it is desired to further improve the resolution response and the glossiness in order to improve the sharpness of the image.

As a support for photographic printing papers having improved resolution response and glossiness, a support for photographic printing papers has been proposed in which a sheet having a vapor-deposited layer of aluminum on a polyethylene terephthalate film is attached to a base paper. (For example, JP-A-1-185551).
However, while the glossiness can be improved by providing a vapor-deposited layer of aluminum, since aluminum has a unique metallic color, the resulting printing paper has a unique metallic gloss different from that of conventional printing paper. It had the drawback of showing.

[0004]

The inventors of the present invention have made diligent studies to solve the above-mentioned drawbacks, and as a result, when the base paper is coated with polyethylene terephthalate containing germanium, it shows no metallic luster. The present inventors have found that the glossiness and the resolution response can be remarkably improved. Therefore, an object of the present invention is to provide a support for photographic printing paper which does not exhibit metallic luster and is extremely excellent in glossiness and resolution response.

[0005]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A support for a photographic printing paper, wherein at least one surface of a raw paper is coated with a layer mainly composed of polyethylene terephthalate, wherein the coating layer contains a metal germanium and / or a germanium compound. Achieved by the support.

In the present invention, "mainly polyethylene terephthalate" is not limited to the case where another resin (called a blended resin) is used in combination within a range of 10% by weight or less.
It is meant to include the case where a pigment such as titanium oxide is added as necessary. Of course, only polyethylene terephthalate may be used.

Blend resins that can be used include polyolefin resins such as polyethylene and polypropylene, polyethylene glycol, polyoxymethylene,
It can be appropriately selected and used from polyether resins such as polyoxypropylene, urethane resins such as polyester polyurethane and polyether polyurethane, resins such as polycarbonate and polystyrene, which can be extruded at 270 to 350 ° C. .

Two or more kinds of the above blended resins may be used at the same time. For example, 6 parts by weight of polyethylene and 4 parts by weight of polypropylene may be mixed with 90 parts by weight of polyethylene terephthalate. In polyethylene terephthalate, powder such as silica may be appropriately contained,
By forming the surface of the cooling roll into a mat shape when laminating by the melt extrusion method, the surface of the coating layer can be made to have a desired roughness.

In the present invention, from the viewpoint of improving the whiteness of the photographic paper, it is preferable that the polyethylene terephthalate coating layer on the side of the emulsion coating layer contains titanium oxide. In this case, it is preferable to uniformly mix and disperse titanium oxide in the coating layer from the viewpoint of enhancing the smoothness of the surface of the support and enhancing the resolution response.

The form of titanium oxide used may be anatase type or rutile type, but its average particle size is preferably 0.1 to 1.0 μm, and particularly,
It is preferably 0.2 to 0.6 μm. Specific products include, for example, KA-10 and KA-20 manufactured by Titanium Industry Co., Ltd.

The metal germanium and / or used in the present invention
Alternatively, the polyethylene terephthalate containing a germanium compound is preferably polyethylene terephthalate obtained by polycondensing terephthalic acid or dimethyl terephthalate and ethylene glycol using germanium dioxide as a catalyst. The germanium in the polyethylene terephthalate in this case is in the state of metallic germanium and / or germanium compound when laminated on the base paper.

The content of germanium in polyethylene phthalate is preferably in the range of 0.001 to 0.05% by weight. The germanium dioxide may be a pelletized germanium dioxide catalyst used when producing polyethylene terephthalate for bottles by a solid-state polymerization method. In the present invention, the germanium dioxide used is particularly preferably hexagonal germanium dioxide from the viewpoint of enhancing the glossiness of the photographic paper.

The polyethylene terephthalate used in the present invention preferably has an average molecular weight of 30,000 or more. The use of 30,000 or less is not preferable because the strength of the coating layer is weakened, crystallization proceeds, and the density easily increases. The coating of polyethylene terephthalate is
It can be easily carried out by a known coating method such as a melt extrusion method, a film sticking method or a solvent dissolution coating method.

The thickness of the layer mainly composed of polyethylene terephthalate coated on the base paper is preferably in the range of 5 to 50 μm, particularly preferably in the range of 10 to 30 μm. If the thickness is 50 μm or more, cracks and the like are likely to occur in the coating layer, and if it is 5 μm or less,
This is not preferable because the support for photographic printing paper is insufficiently waterproof and the rigidity is lowered.

Further, from the viewpoint of sufficiently preventing the curling habit,
It is preferable to provide coating layers having substantially the same thickness on both surfaces. When the base paper is coated with the above-mentioned polyethylene terephthalate, the surface of the base paper may be subjected to a pretreatment such as a corona discharge treatment or an undercoating treatment in advance.

In order to meet the need for tearability in which an unnecessary photograph is torn and easily discarded, polyethylene terephthalate may be directly laminated on the base paper by a melt extrusion method. In this case, when the polyethylene terephthalate layer is subjected to a stretching treatment or a heat treatment, the degree of crystallinity of polyethylene terephthalate increases, so that tearing cannot be easily performed. By applying a photographic emulsion layer on the polyethylene terephthalate coating layer of the support obtained as described above in a known manner, it is possible to obtain a photographic printing paper excellent in glossiness and resolution response as well as water resistance. You can

[0017]

INDUSTRIAL APPLICABILITY In the photographic printing paper support of the present invention, since the base paper is coated with a layer mainly containing polyethylene terephthalate containing germanium, it is excellent in glossiness and is also excellent in resolution response.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 and Comparative Examples 1-3. Thickness 125μ
Polyethylene terephthalate or polyethylene containing 10% by weight of the titanium oxide powder shown in Table 1 on the surface of the m base paper, and the same resin as the front surface except that the titanium oxide powder is not included on the back surface are melt extruded at 300 ° C And coated to obtain a support. A printing paper was obtained by providing an emulsion layer on the surface of the obtained support. Table 1 shows the results of evaluation of the surface glossiness and the resolution response shown below for each of the obtained printing papers.

Surface glossiness A handy gloss meter HG246 type (trade name, manufactured by Suga Test Instruments Co., Ltd.) was used to measure and evaluate reflection gloss at 60 degrees.

Resolution Response The resolution response of a photograph which was developed using a film in which images of 10 fine lines were photographed within 1 mm and printed was evaluated.

[0022]

[Table 1]

In Table 1, PET represents polyethylene terephthalate and PE represents polyethylene, and * indicates that hexagonal germanium dioxide is contained in an amount of 50% by weight or more. Each shows that it contains 60 wt% or more of a fixed germanium dioxide.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sugihiko Tanaka, Fujinomiya City, Shizuoka Prefecture, 200 Onakazato, Fuji Shashin Film Co., Ltd. (56) References JP-A-1-177536 (JP, A) JP-A-1 -189646 (JP, A) JP-A-61-210346 (JP, A)

Claims (2)

(57) [Claims] 1. A support for photographic printing paper, wherein at least one surface of a base paper is coated with a layer mainly composed of polyethylene terephthalate, wherein the coating layer contains a metal germanium and / or a germanium compound. Support for photographic printing paper. 2. A support for photographic printing paper according to claim 1, wherein the germanium compound is hexagonal germanium dioxide.