JPH05232628A - Substrate for photographic printing paper and its production - Google Patents

Abstract

PURPOSE:To produce a substrate for photographic printing paper excellent in response to resolving power and suitability to tear as well as heat resistance. CONSTITUTION:At least one side of base paper is directly coated with polyethylene terephthalate and an Al layer is further formed on the coated side to obtain the objective substrate for photographic printing paper.

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 resolution response and tearability.

[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 has low heat resistance 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 required to further improve the resolution response and the heat resistance in order to improve the sharpness and storability of the image. ing. As a support for photographic printing paper with improved resolution response and heat resistance, a support for photographic printing paper is proposed in which a polyethylene terephthalate film having an excellent heat resistance and an aluminum vapor deposition layer provided on the upper surface is attached to a base paper. (For example, JP-A-1-185551).

[0004]

However, since such a polyethylene terephthalate film is stretched, it is difficult to tear the photographic printing paper, and it is desired to tear and dispose of unnecessary photographs. However, there is a drawback that it cannot fully meet the needs of users.

Therefore, as a result of intensive studies to solve the above-mentioned drawbacks, the present inventors have found that when the base paper is directly coated with polyethylene terephthalate, the tearability is good and the emulsion coating of the polyethylene terephthalate coating layer surface is performed. The inventors have found that the resolution response can be improved by further providing a vapor-deposited layer of aluminum on the side, and arrived at the present invention.

Accordingly, a first object of the present invention is to provide a support for photographic printing paper which is excellent not only in heat resistance but also in resolution response and tearability. Second of the present invention
It is an object of the invention to provide a method for producing a support for photographic printing paper which is excellent in heat resistance, tear resistance and resolution response.

[0007]

The above objects of the present invention are a photographic printing paper support having at least one surface of a base paper directly coated with polyethylene terephthalate, which is coated with the polyethylene terephthalate. This is achieved by a support for photographic paper and a method for producing the same, which is characterized in that an aluminum layer is further provided on one surface. In the polyethylene terephthalate used in the present invention, another resin (referred to as a blend resin) may be used in combination within a range of 10% by weight or less. Therefore, in the present invention, the above-mentioned mixed resin is also included in the concept of polyethylene terephthalate.

Blend resins that can be used include polyolefin resins such as polyethylene and polypropylene, polyethylene glycol, polyoxymethylene,
Polyether resin such as polyoxypropylene, urethane resin such as polyester-based polyurethane and polyether polyurethane, polycarbonate and polystyrene,
The resin can be appropriately selected and used from resins that 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,
It is also possible to make the surface of the coating layer have a desired roughness by forming the surface of the cooling roll into a mat when laminating by the melt extrusion method.

In the present invention, it is preferable that polyethylene terephthalate is directly laminated on the base paper by a melt extrusion method from the viewpoint of improving the tearability of the photographic printing paper. The thickness of polyethylene terephthalate coated on the base paper is preferably in the range of 5 to 50 μm, and particularly preferably in the range of 10 to 30 μm.
When the thickness is 50 μm or more, cracks and the like are likely to occur in the coating layer, and when it is 5 μm or less, the waterproof property of the support for photographic printing paper is insufficient and the rigidity is lowered, which is not preferable. Further, from the viewpoint of sufficiently preventing curl, it is preferable to provide a coating layer having substantially the same thickness on both surfaces.

When the base paper is coated with the 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. The aluminum layer provided on the polyethylene terephthalate layer is usually provided by vapor deposition.

The thickness of aluminum is 300 to 3,000.
It is preferably 0Å, particularly 500 to 1,500Å
Is preferred. If it is 300 Å or less, it is difficult to obtain a desired resolution response, and if it is 3,000 Å or more, the adhesion to the emulsion layer is deteriorated. The aluminum vapor deposition layer can be easily provided by using a known vacuum vapor deposition device. The aluminum vapor deposition layer side is the emulsion coating side.

The support for photographic printing paper of the present invention is obtained by melt-extruding a sheet-shaped polyethylene terephthalate wider than the base paper, laminating directly on both sides of the base paper, wrapping the base paper with polyethylene telephthalate, and then laminating surface. It is preferable that a vapor-deposited layer of aluminum is provided on one of the surfaces and the surface is used as an emulsion-coated surface for production. In this case, the edges of the sheet protruding from the base paper are welded to each other so that the base paper is wrapped in polyethylene phthalate. By doing so, it becomes easy to provide an aluminum vapor deposition layer having a uniform thickness. By coating a photographic emulsion layer on the aluminum vapor-deposited layer of the support obtained as described above in a known manner, it is possible to obtain a photographic printing paper excellent not only in water resistance but also in resolution response and tearability. .

[0014]

In the support for photographic printing paper of the present invention, the base paper is directly coated with polyethylene terephthalate, and the vapor deposition layer of aluminum is provided on the emulsion coating side of the coating layer surface, which is excellent in heat resistance and resolution. Excellent response and tearability. Further, according to the manufacturing method of the present invention, the uniformity of the aluminum vapor deposition layer can be significantly improved.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Examples 1-2 and Comparative Examples 1-3. A photographic paper was obtained by providing a resin coating layer, an aluminum vapor deposition layer and an emulsion layer on both sides of a 125 μm-thick base paper according to the formulation shown in Table 1. The coating layer of polyethylene terephthalate on the emulsion coating side contained 2% by weight of silica having an average particle diameter of 3 μm. For vapor deposition of aluminum, a vacuum vapor deposition apparatus was used and vapor deposition was performed under a vacuum degree of 10 ⁻⁵ torr. Table 1 shows the results of evaluations made by using the photographic paper thus obtained and conducting the following tests of resolution response, heat resistance and tear resistance.

Resolution Response The resolution response of a photograph which was developed by using a film on which images of 10 fine lines were photographed within 1 mm and was printed was evaluated. The surface state of the photograph after the heat-resistant development-baked photographic paper was left at 120 ° C. for 6 hours was visually observed and evaluated. Tearability It was evaluated by whether tearing was possible with the hand.

[0018]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location D21H 27/00 (72) Inventor Sugihiko Tada 200 Onakasato, Fujinomiya-shi, Shizuoka Fuji Photo Film Co., Ltd. Within

Claims (3)

[Claims] 1. A support for photographic printing paper, wherein at least one side of a base paper is directly coated with polyethylene terephthalate, and an aluminum layer is further provided on either side coated with polyethylene terephthalate. A support for photographic printing paper, characterized in that 2. A polyethylene terephthalate melt-extruded onto at least one surface of a base paper, and then aluminum is further vapor-deposited on either one of the surfaces coated with polyethylene terephthalate. A method for manufacturing a support for photographic paper. 3. A method for producing a support for photographic printing paper according to claim 2, wherein a sheet-shaped polyethylene terephthalate wider than the base paper is extruded to be laminated directly on both sides of the base paper and the base paper is wrapped with the polyethylene terephthalate. .