JPS63214484A - Production of thermal transfer sheet - Google Patents

Abstract

PURPOSE:To prevent curling and to enhance the surface smoothness of a receiving layer, by applying a resin composition for forming the receiving layer to the single surface of synthetic resin to form the receiving layer and, after drying, laminating a lining material to the other surface thereof. CONSTITUTION:In order to receive the dye or pigment transferred from a thermal transfer sheet, a resin composition is applied to the single surface of synthetic paper directly or through an intermediate layer and subsequently dried under heating to form a receiving layer while a backing material is laminated to the other surface of the synthetic paper. As the resin component in the resin composition, a polyester resin, a polyurethane resin, a polyamide resin, a urea resin and other material showing bonding having high polarity are used and, as a lining material, cellulose fiber paper or a plastic film is designated. By this method, a sheet receiving thermal transfer generating no curling and having the receiving layer excellent in surface smoothness is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thermal transfer sheet that is used in combination with a thermal transfer sheet and is used to thermally transfer the dye in the thermal transfer sheet to record information according to the information.

[Prior art and problems to be solved by the invention] Thermal transfer recording method is widely used as a recording method in printers such as combiators and word processors, but in recent years, it has been used as a recording method for printers such as combiators and word processors. Attempts have also been made to record natural color photographic images by using a thermal transfer sheet provided with a thermal transfer layer containing a color dye and overlapping recording of cyan, magenta, yellow, etc. For example, it is being used to directly record images on a CRT display.

In such a thermal transfer recording method, when used in combination with a thermal transfer sheet and used as a thermal transfer sheet for recording information, especially for recording natural color photographic images, conventional synthetic paper surface For example, a thermal transfer sheet is used which is coated with a saturated polyester resin or the like and provided with a receiving layer for receiving dyes and the like transferred from the thermal transfer sheet.

However, when the conventional heat transfer sheet mentioned above uses synthetic paper whose resin component is a resin with low heat resistance such as polyolefin resin, if the synthetic paper is stretched during production, the synthetic paper will be damaged by the heat during transfer. There was a drawback that the sheet would shrink, resulting in curling of the sheet.

As a solution to these shortcomings, the applicant has developed a thermal transfer sheet in which a backing material made of cellulose fibers or plastic film is provided on the side opposite to the receiving layer of synthetic paper, and has previously filed an application for a thermal transfer sheet. (Tokuho No. 61-39789) However, ordinary paper is stretched during manufacturing, and if there is residual strain in the synthetic paper due to this stretching, it is necessary to apply a backing material to the synthetic paper. If a method is adopted in which a resin composition for forming a receptive layer is applied onto synthetic paper after lamination and then heated and dried, the synthetic paper tends to shrink due to the heat during drying, while the backing material is pasted on one side of the synthetic paper. However, as a result of the difference in shrinkage between the synthetic paper and the backing material, there is a continuing problem that the resulting thermal transfer sheet curls. This phenomenon was significant when using When using such a thermal transfer sheet and feeding it into a printer to perform particularly photo-like transfer, there is a problem in that the transferred image has low clarity and a beautiful photo-like transfer image cannot be obtained. .

[Means for solving problems]

The present inventors have made this as a result of intensive research in view of the above points, and an object of the present invention is to provide a method for producing a thermal transfer sheet that does not cause curling and has a receptor layer with excellent surface smoothness. That is.

That is, in the present invention, a receptor layer forming resin composition for forming a receptor layer that receives dyes or pigments transferred from a thermal transfer sheet is coated on one side of synthetic paper immediately or through an intermediate layer, and then the receptor layer is coated. The gist of the present invention is a method for producing a thermal transfer sheet, which comprises heating and drying a forming resin composition coating layer to form a receptor layer, and then laminating a backing material to the other side of synthetic paper.

As the synthetic paper used in the present invention, any material can be used as long as it is commonly used as a base material for thermal transfer sheets. For example, polyolefin resin such as polyethylene resin, polypropylene resin, or other synthetic resin is used as the resin component. Examples include those manufactured by adding inorganic fillers and the like and extruding the mixture, and those manufactured by coating extender pigments on the surface of a film made of polystyrene resin or polypropylene resin. , synthetic paper with a paper-like layer containing micropores (for example, commercially available synthetic paper Evo: manufactured by Oji Yuka Synthetic Paper)
is desirable. The micropores in the paper-like layer are, for example,
It can be formed by stretching a synthetic resin in a state containing a fine filler. It is said that the thermal transfer sheet made of the synthetic paper provided with the paper-like layer containing micropores has a high density of image density and no variation in the image when the image is formed by thermal transfer. effective. This is because the fine pores have a heat insulating effect, high thermal energy efficiency, and the fine pores have good cushioning properties. It is thought that this will contribute to Note that it is also possible to provide the paper-like layer containing the above-mentioned micropores directly on the surface of the backing material described below.

In the method of the present invention, first, a direct or intermediate layer is provided on one side of the synthetic paper, and then a resin composition for forming a receptor layer is applied to form a receptor layer that receives dyes, pigments, etc. transferred from the thermal transfer sheet. The coating amount is then heated and dried to form a receptor layer. The following synthetic resins are used as resin components in the resin composition for forming a receptor layer.

■Things with ester bonds.

Polyester resin, polyacrylic acid ester resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin, etc.

■Things with urethane bonds.

Polyurethane resin, etc.

■Having an amide bond.

Polyamide resin (nylon).

■Things with urea bonds.

Urea resin etc.

■Other substances with highly polar bonds.

Polycaproloughthane resin, styrene resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, polyacrylonitrile resin, etc.

In addition to the above-mentioned resins, mixtures thereof or copolymers using heptamers constituting these resins can also be used.

The receptive layer is not limited to a structure in which a uniform layer is formed of the above-mentioned resin, but may also have a sea-island structure, a sea-island structure, etc.
For example, the first region of the receptor layer may be made of a synthetic resin having a glass transition temperature of -100 to 20°C, and the first region of the receptor layer may be made of a synthetic resin having a glass transition temperature of 40°C or higher. $2 regions are respectively formed to expose both the first and second regions to the surface;
At the same time, the first region is formed independently of each other into island shapes, and the length of each island portion in the longitudinal direction is preferably 0.5 to 200 μm. The resin composition for forming a receptor layer may contain various additives such as extender pigments such as silica, calcium carbonate, titanium oxide, and zinc oxide, if necessary. Coating methods such as air knife coating, reverse roll coating, gravure coating, and wire bar coating are used as a method for applying the resin composition for forming the receptor layer. The thickness of the receptor layer is preferably 1 to 30 microns, and the resin composition for forming the receptor layer is usually applied so that the coating amount after drying is about 1 to 20 i/wl.

Examples of the material for the intermediate layer, which is optionally provided between the receiving layer formed from the above-mentioned resin composition and the synthetic paper, include L-saturated polyester, polyurethane, and an organic solvent solution of acrylic ester. Examples of the method for forming the intermediate layer include reverse roll coating, gravure coating, and wire bar coating. The thickness of the intermediate layer is preferably 3 to 15 microns.

As the material for the intermediate layer, either or both of an aqueous solution of a water-soluble synthetic resin and an aqueous synthetic resin emulsion may be used instead of the above-mentioned solution of the synthetic resin in an organic solvent. As the water-soluble synthetic resin, 1) polyacrylamide, various resins containing υ carboxyl groups, such as polyethylene, polyvinyl acetate, etc., 3) cellulose resins, etc. can be used. Synthetic resin emulsion W includes polyacrylic ester, ethylene/vinyl acetate copolymer, polyurethane,
Aqueous emulsion of synthetic resin such as polyester can be used. It is also possible to use a mixture of the water-soluble synthetic resin and the synthetic resin aqueous emulsion carbonate. As a method for forming the intermediate layer using a water-soluble synthetic resin or an aqueous emulsion, an air knife coating method can also be used in addition to the above-mentioned coating method.

Extender pigments such as titanium oxide, zinc oxide, clay, and calcium carbonate may be added to the intermediate layer in order to improve the coating suitability of the paint during formation, the blocking resistance, and the hiding property of the coating film. The amount of the extender pigment is preferably 30 parts by weight or less based on 100 parts by weight of the solid resin content of the intermediate layer.

By providing the above-mentioned intermediate layer between the receiving layer and the synthetic paper, the clarity of the photographic-like transferred image is further improved, and there is an effect that it is possible to prevent roughness of the image, especially in the highlight areas.

The heating temperature for heating and drying the receptor layer-forming resin composition applied directly to one surface of the synthetic paper or via an intermediate layer is preferably 80 to 150°C.

The heating method may be any method as long as it can sufficiently remove the solvent in the resin composition applied to the synthetic paper.
When heat is applied to synthetic paper with a strong tensile seal,
Synthetic paper may stretch and distortion may remain, so deformation of the synthetic paper base material 2 was prevented by heating it with the back side against the heating drum, by biting the periphery, or heating it while fixed. It may be heated in this state. In this way, free deformation is prevented,
In addition, from the viewpoint of continuously processing the synthetic paper base material in the form of a roll, a heating drum 1 is used as shown in FIG. It is preferable to wrap it around and heat it. The heating drum can be either a steam-heated type or an electrically heated type. The number of heating drums is not only one, but two, three,
There may be four or more. Further, when two or more heating drums are used, two heating drums may be used consecutively or a threshold may be set, and the heating effect becomes greater when used continuously. Furthermore, a step of cooling using a cooling drum may be added after using the heating drum.

A surface layer having mold releasability and antistatic properties can be provided on the surface of the receptor layer formed as described above. Furthermore, a release agent and an antistatic agent can be contained in the receptor layer. Furthermore, a mold release agent and an antistatic agent are contained in the receptor layer,
It is also possible to provide a mold release agent and a charger after that. The above mold release agents include polyethylene wax, amide wax,
Examples include solid base waxes such as Teflon powder; fluorine-based and phosphoric acid ester-based surfactants; and silicone oil misaki mold release agents, with silicone oil being preferred. As the above-mentioned silicone oil, an oily one can be used, but a curable type is preferable. Examples of the curable silicone oil include reaction-curing type, photo-curing type, catalytic-curing type, etc. Cured silicone oil is particularly preferred.

The reaction-curing silicone oil is preferably one obtained by reaction-curing an amino-modified silicone oil and a medium-carbon modified silicone oil. When the above-mentioned curable silicone oil is contained as a release agent in the receptor layer, the amount added is preferably 5 to 30 wt% of the resin constituting the receptor layer. When provided as a release agent layer on the surface of the receptor layer, its thickness is preferably 0.01 to 5μ, particularly 0.05 to 2μ.
is preferred.

As the antistatic agent, surfactants such as cationic surfactants (e.g., quaternary ammonium salts, polyamine derivatives, etc.), anionic surfactants (e.g., alkyl phosphates, etc.), zwitterionic surfactants, etc. Examples include surfactants and nonionic surfactants.

When the above-mentioned mold release agent and antistatic agent are contained in the receptor layer, or when they are allowed to bleed after being contained in the cross-receptor layer, they must be added to the resin composition for forming the receptor layer in advance! llW agent,
It is sufficient to contain an antistatic agent. When forming a surface layer having mold releasability and antistatic properties on the surface of the receptive layer after forming the receptive layer, it may be provided immediately after the receptive layer is formed.
Alternatively, it may be provided after bonding the backing material, which will be described later. The surface layer having mold releasability and antistatic properties can be formed by applying the above-mentioned mold release agent or antistatic agent by gravure coating, percoating, etc.

In the method of the present invention, after forming the receptive layer, a backing material is attached to the surface of the synthetic paper opposite to the side where the receptive layer is formed.

Examples of the backing material include cellulose fiber paper or plastic film, and furthermore, a combination of the above-mentioned cellulose fiber paper and plastic film can also be used. Examples of the cellulose delicate paper include wood-free paper, art paper, coated paper, wallpaper, lined paper, paper impregnated with synthetic resin or emulsion, paper impregnated with synthetic rubber latex, paper with internal addition of synthetic resin, and paperboard. Examples include films of polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, methacrylate, polycarbonate, and the like. As the backing material, it is also possible to use the cellulose fiber paper coated with polyolefin or the like in extrusion carbon. The thickness of the backing material is preferably 30 to 500 microns.

Examples of methods for attaching the synthetic paper and the backing material include attaching using a conventionally known adhesive, attaching using an extrusion lamination method, attaching using thermal adhesive, etc. When the backing material is a plastic film, examples include pasting by a laminating method, a calendering method, etc., which also serves as the formation of the backing material at the same time. The above-mentioned sticking means is appropriately selected depending on the materials of the synthetic paper and the backing material. Specific examples of the above adhesive include:
Examples include emulsion adhesives such as ethylene-vinyl acetate copolymer and polyvinyl acetate, water-soluble adhesives such as polyester containing carboxyl groups, and examples of adhesives for lamination include polyurethane adhesives, acrylic adhesives, etc. Examples include organic solvent solution type adhesives.

A slippery layer may be provided on the back surface of the backing material to facilitate taking out the thermal transfer sheets one by one. This slipping layer is made of a methacrylate resin such as methyl methacrylate, a corresponding acrylate resin, a vinyl resin such as vinyl chloride-vinyl acetate copolymer, etc. The slipping layer is coated by the same coating method as the receiving layer. It can be formed by drying. Furthermore, an antistatic agent layer can be provided on the back surface of this slippery layer (or the back surface of the backing material if no slippery layer is provided).

As the antistatic agent, the same ones as mentioned above can be used.

A phototube detection mark detectable by a phototube detection device or the like can be provided on the front surface, particularly preferably on the back surface, of the thermal transfer sheet produced by the method of the present invention. By providing the above-mentioned marks, the thermal transfer sheet can be aligned and accurately set at a predetermined position using a phototube detection device or the like during transfer, and an image can always be formed at an accurate desired position. 1) The type, grade, size, etc. of the thermal transfer sheet was detected. 2) The accuracy of the front and back sides when setting the thermal transfer sheet was detected. 3) The direction of the thermal transfer sheet was detected and the thermal transfer sheet was detected. There are advantages in terms of the work process when actually using the sheet for transfer. The phototube detection mark can be provided using the same material, formation method, etc. as conventionally known phototube detection marks.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Synthetic paper with micropores (thickness 110μ, manufactured by Tamago Paper Manufacturing:
Apply a 5% ethyl acetate solution of chlorinated polypropylene as Bli V- to one side of Epo FPG) using a gravure solid plate, and apply the following composition on top of it. The layer-forming resin composition was applied using a reverse printing method using a plate cylinder of a diagonal plate (basis weight after drying: 61/wl), and then wound around a heated drum at 80°C for 5 minutes. It was heated and dried to form a receptor layer. Then, after leaving it for 7 days to allow the silicone in the receiving layer to bleed to the surface, the silicone was rolled for 120 minutes to solidify the silicone.
Heat treatment was performed at ℃ for 2 minutes.

Resin composition for forming receptor layer Polyester resin (manufactured by Toyozai = 100 parts by weight Vylon 200) Amine-modified silicone (manufactured by Shin-Etsu Kagaku 71 Gaku: KF-
393) Epoxy modified silicone (manufactured by Shin-Etsu 71 Chemical: X
-22-343) Toluene-methyl ethyl ketone 700 l mixed solvent (l:1 by weight ratio) On the other hand, as a backing material, a polyurethane adhesive was applied to one side of commercially available coated paper (thickness 65 μm) toluene-methyl ethyl ketone mixed solvent (weight ratio: 1:1). Apply a solution diluted with 1=1),
After the solvent was blown off with a hair dryer, the synthetic paper on which the receptor layer had been formed was laminated to the surface opposite to the receptor layer to form a thermal transfer sheet.

The receiving layer of this sheet had excellent smoothness. In addition, after this sheet was left in a room temperature atmosphere, the presence or absence of curls was observed on the sheet, but almost no curl was observed. Thermal transfer was carried out using , but no curling of the sheet was observed after printing.

Transfer conditions (1) Thermal head: KMT-85-6MPD 2 (
Head resistance value: approx. 560Ω) (2) Applied voltage = 12v (3) Sub-scanning direction: 611m/m (3:L3+as
sc/1ine) (4) Applied pulse width: 16 ts
ec/11m Example 2 The same resin composition for forming a receptive layer as in Example 1 was applied to the same synthetic paper as in Example 1, and the tensilon applied to the synthetic paper was set to the minimum and dried in a hot air dryer to form a receptive layer. On the non-receiving layer side of the synthetic paper, a high-quality paper (65μ) was coated with polypropylene (coating thickness:
After 15μ), an ethylene-vinyl acetate copolymer emulsion adhesive was applied to the uncoated orchid, and after drying, the adhesive was bonded. The receiving layer of this sheet had excellent smoothness.

In addition, after this thermal transfer sheet was left in a room temperature atmosphere, the presence or absence of curl was observed, but no curl was observed.
C., 90% RH and 60.degree. C., 90% RH, and then measured at room temperature, and almost no curl was observed. Further, thermal transfer was performed on this sheet in the same manner as in Example 1, and no curl was observed after printing.

Example 3 Commercially available cast coated paper (10511 m.
A solution of acrylic resin (Dyanal BR-85 manufactured by Mitsubishi Rayon) in a mixed solvent of toluene and methyl ethyl ketone (weight ratio 1:1) was applied to this non-glossy surface using Myabar (dry weight: 2171'). ) L, After drying, add an antistatic agent (Ipposha Yushi Kogyo ■a: Eretat) M
-65) 10 parts by weight of Improvil alcohol 50 fU
The pressure liquid dissolved in part i was coated on a peta plate of a gravure roll (coating amount as a solution: 7 i/l).The same polyurethane adhesive as in Example 1 was applied to the glossy surface of this backing material.
The synthetic paper on which the receptor layer was formed in the same manner as in Example 1 was laminated with the side on which the receptor layer was not formed to obtain a thermal transfer sheet. The receiving layer of this sheet had excellent smoothness. In addition, this sheet showed no curling after being left at room temperature, as well as at 40°C, 90% RH and 60°C, 90% RH.
Almost no curling was observed under any of the following environments, and when the sheet was transferred under the same conditions as in Example 1, no curling was observed on the sheet after printing.

Example 4 Using a stretched polypropylene film (thickness 60μ) treated with corona discharge as a backing material, and using the same urethane adhesive as in Example 1 on the corona discharge treated surface, Example 1
A sheet of synthetic paper without a receptor layer formed thereon in the same manner as above was laminated to form a thermal transfer sheet. The receiving layer of this sheet had excellent smoothness. The octopus sheet showed no curl after being left in an atmosphere at room temperature.
Curling at 0° C., 90% RH and 60° C., 90% RH was hardly observed, and no curling was observed after thermal transfer was performed under the same conditions as in Example 1.

Comparative Example 1 After laminating the same synthetic paper and backing material as in Example 1, a receiving layer similar to that in Example 1 was formed on the other side of the synthetic paper, and the thermal transfer sheet was bound. In addition, when this sheet was left in a room temperature atmosphere and the diameter was measured, the curl of this sheet was severe (10 μm).
As a result of measuring the curl height on an m square sheet, the maximum was 67
Some curls were observed.

〔Effect of the invention〕

As explained above, the method of the present invention employs a method in which a resin composition for forming a receptive layer is coated on one side of synthetic paper and dried by heating to form a receptive layer, and then a backing material is laminated on the other side of the synthetic paper. We manufacture a thermal transfer sheet that does not cause curling and has an excellent smoothness on the surface of the receiving layer, resulting in extremely beautiful transferred images even when transferring photographic images. can do. (9) The thermal transfer sheet obtained by the method of the present invention has excellent effects such as not curling even when exposed to heat during thermal imaging.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIG. 1 is a diagram showing one technique of the method of the invention. 1... Heating drum 2... Synthetic paper

Claims (4)

[Claims] (1) After applying a receptor layer forming resin composition to one side of the synthetic paper immediately or via an intermediate layer to form a receptor layer that receives dyes or pigments transferred from the thermal transfer sheet,
1. A method for producing a thermal transfer sheet, which comprises heating and drying a layer coated with a resin composition for forming a receptor layer to form a receptor layer, and then laminating a backing material to the other side of the synthetic paper. (2) The thermal transfer sheet according to claim 1, wherein one degree of heating is 80 to 150°C. (3) A method for producing a thermal transfer sheet according to claim 1 or 2, in which the synthetic paper is heated while maintaining its dimensions. (4) The method for producing a thermal transfer sheet according to claim 3, wherein the synthetic paper coated with the resin composition for forming a receptor layer is wound around a heating drum and heated.