JPH0415118B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transferable cover film for color hard copy photographic paper that can easily form a colorless and transparent protective layer on the surface of color printed photographic paper.

To explain in more detail, it is a cover film whose purpose is to protect the color image that is transferred from the transfer paper made using sublimation dye to the photographic paper side and to develop the color of the dye, and it is applied as a continuous layer on the substrate. However, a protective layer can be formed for the image by melting and transferring the resin to only the desired part by heat-pressing from the base material side using a heat-sensitive head, etc., and the rest can be easily removed along with the base material. This invention relates to a cover film for color hard copy photographic paper.

A color image can be formed on the photographic paper by heating transfer paper coated with ink using sublimable dye using a thermal head and sublimating the dye in the necessary areas, but the resulting image has the following characteristics: A problem arose.
Although the sublimation-dyed dye is adsorbed onto the surface of the photographic paper, it is not sufficiently diffused, and some of the dye remains as aggregates, so that it does not show the original color development of the dye. For this reason, it was necessary to heat the print again after printing to thermally diffuse the dye. Furthermore, dyes that have been dyed are easily discolored by, for example, oils transferred from hands, and are also easily discolored by ultraviolet rays contained in natural light. In order to solve this problem, a method of heat-pressing a protective film with a thin heat-adhesive layer on the surface of a polyester film, etc. was considered, but color copies made by forming these protective films were Due to the expansion and contraction of the protective film caused by heat, the product curls significantly, and it is necessary to handle the product by cutting it to the same size as the photographic paper. As a result of the study, in order to form a protective layer with less curling, it is preferable that the thickness of the resin layer is 20 μm or less; if the protective layer is thicker than this, the curling will be large and the product value will be greatly reduced. In order to form a resin layer, a resin layer of at least 1 μm or more was required. However, there are many difficulties in heat-pressing such a thin film onto a color copy without wrinkles or the like.

In order to solve the above-mentioned problems, the inventors of the present invention first formed a heat-resistant base material and a heat-resistant base material, did not have adhesive properties to the heat-resistant base material, and applied heat to the surface of photographic paper. We have proposed a transferable cover film that can be melt-transferred to form a colorless and transparent protective layer. With this transfer cover film, it has become possible to easily form a protective layer with less curl on photographic paper, but since the cover layer to be transferred is a continuous body and cannot be easily cut, it must be cut beforehand. , place it on the photographic paper, being careful not to let it protrude to the side, pass it through a laminator, heat it, and fuse it.
Thereafter, only the heat-resistant base material had to be peeled off to form a protective layer. Therefore, it was not possible to feed the cover film in a continuous form to a laminator and transfer only the necessary portions to form a protective layer on the photographic paper. This complicates the process of forming a protective layer on the photographic paper, and also causes dust to get caught up in the paper during handling, or the heat roll for the laminator to be soiled if the front and back sides are mistaken. There has been a demand for a cover film that can be transferred onto photographic paper from a heat-resistant base material to form a protective layer.

The present invention solves these problems and provides a continuously supplied cover film that can optionally form a colorless and transparent protective layer with a thickness of 1 to 20 .mu.m on a color copy only in necessary areas.

That is, in the present invention, a thin resin film that does not adhere to the base material is formed on one side of a heat-resistant base material, or a release treatment is performed on the heat-resistant base material surface in advance, and then a sublimable dye is applied thereon. This is a cover film for color hard copy photographic paper of a sublimation transfer type, which forms a resin layer that diffuses and adsorbs and only the heated portion is easily melt-transferred to the surface of the photographic paper and peeled off from the base material.

Next, the present invention will be explained with reference to the drawings. 1st
6 to 6 are diagrams showing the structure of a transferable cover film according to the present invention.

Figure 1 shows a resin layer C that becomes a transparent protective layer formed on a heat-resistant base material A through a resin thin film B that has no adhesive properties with the base material A.
This is the case where the structure is made by depositing

FIG. 2 shows a case in which a resin layer C is adhered to the surface of a heat-resistant base material A that has been subjected to a peeling treatment.

FIG. 3 shows a case in which a resin layer D serving as a transparent protective layer is deposited on a heat-resistant base material A with a resin thin film B interposed therebetween.

FIG. 4 shows a case in which a resin layer D is adhered to the surface of a heat-resistant base material A that has been subjected to a peeling treatment.

FIG. 5 shows a case in which a resin layer E serving as a transparent protective layer is adhered to a heat-resistant base material A via a resin thin film B.

FIG. 6 shows a case in which a resin layer E is adhered to the surface of a heat-resistant base material A that has been subjected to a peeling treatment.

Heat-resistant base material A is polyester, polycarbonate, polyarylate, polyeutersulfone,
Smooth surfaces such as polyimide, polyamide, polyamideimide, polyfluoroethylene, etc., or if necessary, pear surface treatment, peeling treatment,
Relatively heat-resistant plastic film base materials and paper with metalized surface treatments such as Al, Zn, and Cv;
This is a base material in which the above-mentioned base materials are bonded together using metal foil or the like, if necessary. The thickness of base material A is 5 to 100μ,
The thickness is preferably 8 to 50 μm, and is selected in consideration of ease of handling and ease of welding during heating.

The resin thin film B shown in FIGS. 1, 3, and 5 does not adhere to the heat-resistant base material, is relatively hard, and easily breaks with a relatively weak force when the cover layer is melt-transferred onto the photographic paper. The resulting resin consists of a thin film of resin that is easily dissolved by heating. Examples of these resins include cellulose acetate resin, methyl methacrylate resin, epoxy resin, styrene resin,
Gelatin is a typical example, and it itself is highly transparent, hard and brittle, or has a sharp melting point with respect to temperature, and heat-resistant base materials are limited to those that do not have adhesive properties. Transparent inorganic particles, fine resin powder, and low-molecular-weight polymers with a melting point may be dispersed in these resins in order to make them brittle and easy to cut, or to sharpen their meltability with respect to temperature.

The resin layer C in FIGS. 1 and 2 is a porous foam layer made of a highly transparent resin capable of diffusing and adsorbing sublimation dyes. Such a porous foam layer can be obtained by foaming a foaming agent uniformly dispersed in a resin by heating, or by rapidly drying a solvent with a low boiling point. Also included in this range are brittle resin films in which the solubility is deliberately lowered during coating film formation by cooling due to the latent heat of vaporization during drying or by mixing with a poor solvent, resulting in a whitening phenomenon. The resin layer C obtained in this way is sensitive to heat and pressure, and instantly melts and transfers only the heated part to form a transparent protective layer, but the unheated part is brittle and porous. Since it is a foam layer, it is easily torn off from the protective layer transferred onto the photographic paper and remains on the substrate side. The resin used here is generally transparent, adsorbs and diffuses sublimable dyes well, and is not particularly limited as long as it has adhesive properties with the processing agent on the surface of the photographic paper, but examples include polyester resin, epoxy resin, Examples include styrene resin, a mixture of epoxy resin and acrylic resin. Further, in order to increase the sensitivity to heat, it is even more effective to disperse or dissolve a low molecular weight substance having a low melting point, such as a crystalline polyester low molecular weight substance, an epoxy low molecular weight substance, a styrene low molecular weight substance, etc.

The resin layer D in FIGS. 3 and 4 consists of a dispersed layer of highly transparent powder particles capable of diffusing and absorbing sublimation dye. For example, in this resin layer D, 20 to 90% by weight of resin powder having a melting point and softening point lower than that of the solid base material, such as modified rosin or low molecular weight substances such as terpene phenol, is dispersed in polyester resin, polystyrene resin, or epoxy resin. It consists of a resin layer that has been heated and pressurized, and only the areas that are heated and pressed easily melt and transfer onto the photographic paper, while the areas that are not heated are brittle and easily tear off due to the dispersed resin powder that is contained therein. The exposed portion is detached from the heat-resistant substrate and can be formed as a transparent protective layer on the photographic paper.

The resin layer E in FIGS. 5 and 6 is a transparent and uniform resin layer made of compatible resins that themselves exhibit a temperature-sensitive melting point or softening point, and is heated by a heat-sensitive head. Only that part is easily melted and melted into the photographic paper, thereby transferring and forming a protective layer on the photographic paper. Examples of resins used for this purpose include paraffin wax, microcrystalline wax, carnauba wax, beeswax, chlorinated paraffin petroleum resin, and low-molecular polyethylene. This is a heat-sensitive transfer resin layer created by adding some oil such as linseed oil or mineral oil, and adding transparent inorganic powder to make it easier to cut.

According to such a cover film for color hard copy photographic paper, only the resin layer heated by the thermal head melts and transfers to the surface of the photographic paper to form a transparent protective layer, and the remaining resin layer is cut off. It can be easily separated from the base material. Therefore, the cover film can be supplied as a connected body and only the necessary portions can be transferred onto the surface of the photographic paper to form the protective layer, thereby improving the efficiency of forming the protective layer on the photographic paper.

Next, the present invention will be explained with reference to examples.

Comparative Example 1 25μ coated with one side treated with silicone release agent
Polyester resin internally plasticized on the surface of polyester film (Vylon #200, manufactured by Toyobo Co., Ltd.)
was applied to a dry thickness of 7 μm to obtain a transfer cover film. On the other hand, an image was formed by sublimating the dye onto photographic paper using a heat-sensitive head from the back side of a heat-sublimable ink ribbon produced by printing ink containing a sublimable dye on thin paper. A transfer cover film was placed on top of this photographic paper, and only the image forming area was heated with a heat-sensitive head from the back of the cover film to complete the coloring of the dye while forming a protective layer on the image area on the photographic paper. After that, I tried to peel off the transfer cover film from the photographic paper, but the cover film could not be peeled off cleanly from the heated area, and the cover film peeled off including the unheated area, and the photographic paper processing layer or paper was destroyed along with the image. Ivy.

Comparative Example 2 A transfer cover film was created by forming a cellulose acetate propionate resin layer of about 3μ on the surface of a 25μ polyester film, and then further forming a resin layer of about 3μ of the internally plasticized polyester resin described above. did. This cover film was placed over the image on the photographic paper prepared in Comparative Example 1, and only the image portion was heated and melted from the back side of the cover film to form a protective layer. After that, I tried to peel off the base film of the transfer cover film and the excess cover resin layer from the photographic paper, but as in Comparative Example 1, the cover resin layer was difficult to cut and the treated layer of the photographic paper was destroyed. Ivy.

Example 1 A toluene solution of methyl methacrylate resin was coated on one side of a 12μ polyester film so that the dry coating film had a thickness of 1μ. On top of this, a resin solution consisting of a mixture of MEK, a polyester resin with a Tg of 67℃, acetone, and methanol was applied, and the temperature was immediately raised to 100℃.
Approximately 10μ whitened by forced boiling drying at a temperature above
A resin layer was formed. Combine this melt transfer cover film with the photographic paper prepared earlier, and
Using a thermal head set at 170℃, the cover film was heated from the back side to melt the whitened resin layer. After that, the cover film was peeled off from the photographic paper, and only the heated part was transferred to the photographic paper side. The remaining cover resin layer was easily peeled off from the photographic paper together with the base polyester film. The melt-transferred cover layer was sufficiently transparent and the dye was sufficiently colored.

Example 2 A whitened polyester resin layer of about 10 μm was formed on the surface of the 12 μm polyester film that had been subjected to the peeling treatment in the same manner as in Example 1. A protective layer is formed on the photographic paper using a heat-sensitive head in the same manner, and when it is peeled off, a transparent polyester resin cover layer is formed only in the image area of the photographic paper, and the remaining resin is easily peeled off along with the base polyester film. done.

Example 3 After forming a cellulose acetate resin layer of approximately 1μ on a 12μ polyester film, a polyester resin with a melting point of 123°C (Vylon #300 manufactured by Toyobo Co., Ltd.), chlorinated paraffin fine powder, and rosin ester with a softening point of 80°C were added. An aqueous dispersion of powder (manufactured by Arakawa Chemical Industries, Ltd.) in a ratio of 6:3:1 was applied to a dry thickness of approximately 10 μm and dried.

After fusing only the image part to the photographic paper in the same manner as in the comparative example, when the transfer cover film was peeled off from the photographic paper, a transparent protective layer was formed only in the image part, and the rest could be peeled off together with the base material. Ta.

Example 4 Finely powdered silica on one side of 6μ polyimide film
20 parts, carnauba wax 20 parts, ester wax
45 parts of mineral oil, 10 parts of mineral oil, and 5 parts of antioxidant were melt-kneaded and applied to a thickness of about 7 μm. Photographic paper was placed on the transfer cover film thus produced, and the front surface of the image area was heated from the polyimide side at 300° C. for 10 msec at a time with a heat-sensitive head to fuse the resin onto the photographic paper. After that, the cover film was peeled off from the photographic paper.
It could be easily peeled off, and a transparent and glossy protective layer could be formed on the image.

Example 5 70 parts of chlorinated paraffin (Enpara 70, manufactured by Ajinomoto Co., Ltd.) with a softening point of 100°C and a polyester resin (Vylon #200, manufactured by Toyobo Co., Ltd.) with a softening point of 163°C were added to one side of a 12μ polyester film that had been subjected to a peeling treatment. ) 20 parts, plasticizer DOP 9 parts, oleic acid acid (Diamond O.200, manufactured by Nippon Kasei Co., Ltd.) 1 part
A resin solution obtained by dissolving in MEK was applied to a dry thickness of 5μ. This cover film and photographic paper on which an image had already been formed by transfer of sublimable dye were combined and pressed using a hot press set at 180°C. After taking it out from the press, when the cover film and photographic paper were peeled off, only the pressed part was neatly transferred to the photographic paper side, forming a transparent protective layer, and the rest could be easily peeled off along with the base material.

[Brief explanation of drawings]

1 to 6 are cross-sectional views showing embodiments of the cover film according to the present invention. A is a heat-resistant base material, B is a resin thin film, and C, D, and E are resin layers each serving as a protective layer.

Claims (1)

[Scope of Claims] 1. A color hard copy consisting of a heat-resistant base material and a resin layer formed on the base material, in which the resin layer is melted and transferred to the surface of photographic paper to which a sublimable dye has been transferred by heating. A color hard copy of a cover film for photographic paper, characterized in that the resin layer is melted and transferred onto the surface of the photographic paper by heating, and only the heated portion of the resin layer is peeled off from the heat-resistant base material. Cover film for photographic paper. 2. A patent claim characterized in that the resin layer is formed by dispersing transparent resin particles having a lower melting point or softening point than the matrix and capable of adsorbing and diffusing sublimable dyes in a transparent resin matrix that adsorbs and diffuses sublimable dyes. A cover film for color hard copy photographic paper according to item 1. 3. The cover film for color hard copy photographic paper according to claim 1, wherein the resin layer is a porous foam layer made of a transparent resin that adsorbs and diffuses sublimable dye.