JPH04298394A - Manufacture of sublimation type thermal transfer print - Google Patents

Abstract

PURPOSE:To provide the manufacture of a sublimation type thermal transfer print having the improved shelf stability of a transfer image. CONSTITUTION:A sublimation type thermal transfer print having the improved shelf stability of a transfer image is manufactured in such a manner that an image is formed to the dye acceptor layer of acceptor paper, to which said dye acceptor layer containing a resin having film formability on a base material sheet is formed, through sublimation type thermal transfer printing and the image-formed acceptor paper is thermally treated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sublimation type thermal transfer print, and more particularly to a method for manufacturing a sublimation type thermal transfer print with improved preservation of transferred images.

0002

BACKGROUND OF THE INVENTION In recent years, with the development of signal processing technology, the quality of image signals has improved markedly. In particular, the signal frequency band is becoming higher, and improvements in video signal formats and broadcasting systems are being actively made. As a result, it is becoming easier to obtain and use high-quality image data. Furthermore, the use of electronic storage for still images is progressing, and the transition from optical silver halide photographic recording methods to electronic storage of electronic still photographs is also gaining momentum. Electronic storage converts image information into electrical signals and stores them, so image information can be stored at high density and data can be easily transferred and processed. Furthermore, digitization of signals is progressing, and storage and reproducing systems with extremely low signal deterioration are being constructed.

[0003] In response to the increasing quality of image information, there has been a demand for high-quality printing methods, and in recent years, thermal transfer printing methods such as sublimation type thermal transfer printing and melting type thermal transfer printing have been developed. Various non-impact printing methods, such as electrophotography, inkjet printing, and silver halide photography, are being actively developed.

[0004] Among these printing methods, dye sublimation thermal transfer printing can provide high quality images with density gradation, and also has a relatively simple printing mechanism and does not require much maintenance. Since then, video printers for home use have become popular.

[0005] Dye sublimation thermal transfer printing consists of a coloring material layer of a transfer film having a coloring material layer containing a sublimation dye, and a dye receiving layer (hereinafter often referred to as "receiving layer") of a receiving paper having a dye receiving layer containing a resin having film-forming ability. This is done by heating the two layers in close contact with each other using a thermal printing means such as a thermal head, thereby transferring the sublimable dye in the coloring material layer to the receiving layer. The color material layer of this transfer film has three colors: yellow, magenta, and cyan (in some cases, four colors including black).
A color image is reproduced by sequentially printing each color one on top of the other on the same receptor layer surface.

A problem with printed materials obtained by sublimation thermal transfer printing is that the images obtained by printing have a low shelf life. In other words, compared to printed matter obtained by other printing methods, when the receiving layer side of the printed matter comes into contact with other objects during storage, the dye forming the image is more likely to transfer to the object that has come into contact with it, for example, Images obtained by dye-sublimation thermal transfer printing have the disadvantage of particularly low resistance to plasticizers, as dyes can transfer to vinyl sheets that contain plasticizers by simply leaving them at room temperature for a while. have.

In addition, the image is usually sensitive to friction; for example, the dye can be easily removed by rubbing the image side of the printed matter several times with an eraser, or the image side may be rubbed against the printed side, on the back side of the receiving paper, or by other objects. It has the disadvantage that the image is easily damaged when rubbed.

[0008]Furthermore, among the storage properties, sufficiently good color fading resistance due to light (light resistance) and color fading resistance due to heat (dark fading resistance) have not always been obtained.

The present invention is directed to solving the problems of the prior art as described above, and an object of the present invention is to provide a method for obtaining a dye sublimation thermal transfer print having a high shelf life. .

0010

[Means for solving the problem] Dye sublimation thermal transfer printing is a method in which the dye in the color material layer of the transfer film is sublimated and at the same time transferred to the receiving layer of the receiving paper by thermal diffusion. Since the dye transferred to the receptor layer is mainly localized near the surface of the receptor layer, it is susceptible to external influences such as plasticizers, friction, light, and heat.
As a result of various studies based on the knowledge that it should be possible to improve storage stability if the dye transferred to the receptor layer by printing is sufficiently transferred into the interior of the receptor layer without being localized near the surface. discovered that the storage stability of receiving paper subjected to dye sublimation thermal transfer printing could be improved by subjecting it to a specific treatment, leading to the completion of the present invention.

That is, the method for producing a dye-sublimation thermal transfer printed matter according to the present invention provides a method for producing a dye-receiving layer of a receiving paper in which a dye-receiving layer containing a resin having film-forming ability is formed on a base sheet. The method is characterized in that after an image is formed by sublimation type thermal transfer printing, the receiving paper on which the image has been formed is subjected to a heat treatment.

Japanese Patent Laid-Open No. 2-551 discloses a method of imparting a desired surface condition to the surface of a transferred image by subjecting the surface of a printed matter subjected to sublimation thermal transfer to a post-treatment such as pressure treatment.
It is described in Publication No. 90. That is, the processing method is to laminate a surface conditioning sheet such as paper or synthetic resin film on the surface of the receptor layer on which an image has been recorded by sublimation thermal transfer, pressurize it, and heat it if necessary. The purpose of this method is to make the image of a thermal transfer image similar to that of a general printed matter or photograph by subjecting it to a surface post-treatment. This process applies pressure to the surface of the receptor layer on which an image has been recorded, creating a condition corresponding to the condition of the surface (rough surface or smooth surface) in contact with the receptor layer of the laminated surface conditioning sheet, and It modifies the surface texture to a desired state.

However, the present invention is directed to improving the storage stability of transferred images by heat-treating the receiving paper on which the image is produced by transferring dye by sublimation thermal transfer printing. By such heat treatment, the dye transferred to the receptor layer can be transferred from the surface area of the layer to a deeper area, and as a result, the storage stability of the printed image can be dramatically improved. It was completed based on this knowledge.

The present invention will be explained in more detail below.

The receiving paper used in the present invention has a dye-receiving layer on one or both surfaces of the base sheet.

The base sheet of the receiving paper does not need to be special, and may be, for example, synthetic paper (polyolefin-based, polystyrene-based, etc.), high-quality paper, art paper, coated paper, cast coated paper, wallpaper, or lined paper. , synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internally added paper, paperboard, etc., cellulose fiber paper, polyolefin paper such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. Various plastic films or sheets can be used, and white opaque films formed by adding white pigments and fillers to these synthetic resins, foamed sheets, etc. can also be used.

Furthermore, a laminate made of any combination of the above base sheets can also be used as the base sheet. Typical examples of laminates include laminates of cellulose fiber paper and synthetic paper, or cellulose fiber paper and plastic films or sheets. The thickness of these base sheets may be arbitrary, for example, 10 to 300 μm.
Generally, the thickness is about 100%.

The resin having film-forming ability contained in the dye-receiving layer of the receiving paper is not particularly limited as long as it has film-forming ability, and examples thereof include resins having fatty acid vinyl ester units, vinyl chloride resins, vinylidene chloride, etc. Resin, polyamide, polyethylene, polycarbonate, polystyrene, polypropylene, acrylic resin, phenolic resin, polyester, polyurethane, epoxy resin, silicone resin, fluororesin, butyral resin, melamine resin, polyvinyl alcohol, cellulose resin, maleic anhydride copolymer resin, Examples include polymeric substances such as mixtures, copolymers, and modified products of these resins. These polymeric substances can be used alone or in combination of two or more.

Among the resins having film-forming ability, resins having fatty acid vinyl ester units are preferred as resins contained in the receptor layer of the receptor paper to which the present invention is applied. Further, the content of vinyl acetate units in the vinyl acetate resin preferably used in the present invention is preferably 18% by weight or more, more preferably 30% by weight or more. When the proportion is less than 18% by weight, there is a tendency that the effect of improving storage stability by heat treatment is not sufficient. Examples of the fatty acid vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, vinyl laurate, etc.
Vinyl acetate and vinyl propionate are preferred. Also,
The units other than the fatty acid vinyl ester units constituting the resin having fatty acid vinyl ester units are monomer units copolymerizable with the fatty acid vinyl ester, and the monomers include vinyl halides (vinyl chloride, fluoride, etc.). (vinyl chloride, etc.)
, vinylidene halides (vinylidene chloride, vinylidene fluoride, etc.), (meth)acrylate compounds [(meth)
Methyl, ethyl, butyl, erhexyl esters of acrylic acid, glycidyl (meth)acrylates, (meth)acrylates containing hydroxyl groups, fluorine atoms, phosphorus atoms, sulfur atoms, etc., (meth)acrylates containing oxyethylene and/or oxypropylene units, etc. ) acrylate, (meth)acrylate having a tetrahydrofurfuryl group], olefins (ethylene, propylene, etc.), polymerizable acid amides [(meth)acrylamide, etc.], polymerizable basic acids [crotonic acid, isocrotonic acid, (meth)acrylic acid, etc.] and their esters and salts, polymerizable polybasic acids (maleic acid, fumaric acid, itaconic acid, etc.) and their esters and salts, anhydrides of polymerizable polybasic acids (maleic anhydride, etc.), Examples include compounds having a glycidyl group (allyl glycidyl ether, etc.), alkyl vinyl ethers, aromatic vinyls (styrene, methylstyrene, etc.), macromonomers, (meth)acrylonitrile, vinylpyrrolidone, and the like.

The resin having fatty acid vinyl ester monomer units is one having one or more fatty acid vinyl ester monomer units, or one or more fatty acid vinyl ester monomer units and fatty acid vinyl ester. and one or more types of monomer units that can be copolymerized, or a mixture thereof.

[0021] Furthermore, the resin having units of fatty acid vinyl ester monomer may include a resin having units of fatty acid vinyl ester monomer as a backbone, monomers therein, and a resin having film-forming ability. A graft copolymer resin in which a fatty acid vinyl ester monomer is graft-polymerized to the trunk, and a part of the fatty acid vinyl ester units in the resin having fatty acid vinyl ester monomer units is converted into vinyl alcohol units by a saponification reaction. Converted resins and the like are included. Furthermore, the above resin having units of fatty acid vinyl ester monomer also includes resins having units of fatty acid vinyl ester monomer chemically bonded to other substances.

The vinyl acetate resin preferably used in the present invention is obtained by polymerizing vinyl acetate by a known method such as solution polymerization, suspension polymerization, emulsion polymerization, or bulk polymerization, or by polymerizing vinyl acetate and vinyl acetate. It can be obtained by copolymerizing other copolymerizable monomers. In order to obtain a mixture of vinyl acetate polymer and vinyl acetate copolymer, in addition to the method of obtaining each separately and then mixing the two,
It can also be obtained by adding another monomer copolymerizable with vinyl acetate to the reaction system during the polymerization reaction of vinyl acetate, continuing the polymerization, and then terminating the reaction.

When it is desired to improve the dye-dyeability of the receptor layer, for example, the receptor layer may contain amorphous polyester, thermoplastic polyurethane, etc. in addition to a resin having fatty acid vinyl ester monomer units, or This is possible by selecting a resin that has ester monomer units that have excellent dye stainability, such as vinylidene chloride, vinyl chloride, etc., that has monomer units that have the effect of improving dye stainability. It is. The proportion of the above-mentioned polyester or polyurethane contained in the receptor layer is preferably 3 to 50 parts by weight, particularly preferably 5 to 20 parts by weight, based on 100 parts by weight of the resin having fatty acid vinyl ester monomer units. Also,
The ratio of monomer units having the effect of improving dye stainability in the resin containing units of the fatty acid vinyl ester monomer having excellent dye stainability can be up to 82% by weight.

[0024] In the present invention, the receiving paper is prepared by applying a resin having film-forming ability to the surface of a base sheet in the form of a solution, dispersion, melt, etc., and drying as necessary to form a receiving layer. can be used. For example, a solution, emulsion, or molten resin containing a resin with film-forming ability and various additives added as necessary is applied onto a substrate, and drying, cooling, calendering, etc. are performed as necessary. It can be obtained by

[0025] In order to obtain the coating solution as described above, resins having film-forming ability such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, isobutyl acetate, trichlene, chlorobenzene, toluene, and tetrahydrofuran are used. It can be obtained by dissolving or dispersing it in a single solvent such as or a mixture of two or more solvents. Further, the resin solution obtained by solution polymerization can be used after removing unreacted monomers or adjusting the concentration, if necessary. An emulsion-like coating solution can be obtained by emulsifying the resin used, but it is convenient to use an emulsion-like resin obtained from an emulsion polymerization solution. It is also preferable to use the components in the form of an emulsion.

To form a dye-receiving layer on a substrate, such as a plastic film, sheet, cellophane, paper, etc., a bar coater, direct gravure coater, offset gravure coater, top feed reverse coater, bottom feed reverse coater, blade coater, etc. are used. This can be achieved by applying a resin solution or emulsion capable of forming a film onto a substrate and drying it using a known method and apparatus used for applying resin solutions, resin emulsions, paints, and the like. In addition, in order to provide a dye-receiving layer by coating a high-temperature molten film-forming resin containing various additives on a substrate, a so-called solution coating method is used, in which molten resin is applied to paper, plastic films, sheets, etc. It can be carried out. Furthermore, a receiving paper having a receiving layer can also be obtained by a multilayer coextrusion method using a resin forming the receiving layer and a resin forming the base material so that the receiving layer becomes the outermost layer.

[0027] The above-mentioned receptor layer may contain various substances in addition to the resin having film-forming ability, if necessary.
Examples of these substances include white inorganic particles (titanium oxide, calcium carbonate, calcium phosphate, clay, diatomaceous earth, zinc oxide, silica, etc.), mold release agents (silicon compounds, fluorine compounds, amide compounds, (polyethylene wax, surfactant, etc.), stabilizers, plasticizers, fillers, lubricants, foaming agents, antistatic agents, etc.

[0028] The receiving paper also has a release agent and a release agent on its surface.
It may be coated with an antistatic agent or provided with a slippery layer on the surface to improve the sliding between the surfaces of the receiving paper.

In the method of the present invention, the receiving paper and transfer film obtained as described above are used to carry out dye sublimation thermal transfer printing in the manner described above, and the resulting printed matter is further heat-treated. To obtain a sublimation type thermal transfer printed matter with excellent image storage stability.

[0030] This heat treatment can be performed on either one side or both sides of the printed matter, and can be repeated once or twice or more. When performing this treatment two or more times, the heating temperature may be the same or different. In order to make this heat treatment of printed matter more effective, the receiving paper before printing was
It is also possible to perform printing after preheating to a temperature in the range of 0 to 150°C, and then perform the above-mentioned heat treatment. The temperature of the heat treatment in the present invention is preferably in the range of 100 to 200°C, particularly preferably 120 to 150°C. Heating temperature is 100
If heated below 200°C, the transferred dye will not be sufficiently thermally diffused and the effect of improving storage stability will tend to be reduced, which is undesirable.On the other hand, if heated above 200°C, the resin, dye, etc. that form the receptor layer will be damaged. This is not preferable as it tends to deteriorate due to heat.

The above-mentioned heat treatment (and preheat treatment if necessary) can be performed by, for example, oven heating, Yankee cylinder heating, microwave heating, far infrared heating, hot air heating, or the like. This heat treatment and preheating process can be performed either inside or outside the thermal transfer device; It can be used for. The conditions for heat treatment and preheating may be the same or different.

[0032] Although it is not necessarily clear why the heat treatment as described above significantly improves storage stability, the above heat treatment effectively improves the transfer dye that has been localized near the surface of the receptor layer by thermal transfer printing. It can be assumed that the storage stability is improved due to this migration.

Further, in the present invention, the time for the above heat treatment varies depending on the treatment temperature and heating method, but is at most 1
About a minute is sufficient. Therefore, it becomes possible to significantly improve storage stability by short-time heat treatment. Furthermore, the method of the present invention does not require additional or complicated means other than the above-mentioned heat treatment, such as pressure treatment. To provide a dye-sublimation thermal transfer printed material which improves the plasticizer resistance, light resistance, dark fading resistance, etc. of a printed image and has excellent preservability such as resistance to friction by a simple and quick method of simply heating treatment. The method of the present invention can be applied to a receiving paper having a dye-receiving layer containing a resin having film-forming ability, and an image has been transferred and printed on the dye-receiving layer by sublimation thermal transfer printing. However, there are no limitations on the receiving paper and its receiving layer, the transfer film and its coloring material layer, transfer conditions, transfer device, etc. used to obtain the printed matter.

[0034]

EXAMPLES The present invention will be explained below based on examples.

[0035] In the following examples, storage stability was measured by the following method. (1) Reflection optical density Measured using a reflection densitometer (RD9141 manufactured by Macbeth). (2) Plasticizer resistance test First, the reflection optical density of the printed surface of the sample print to be used was measured, and this was taken as the reflection optical density before the test. Next, vaseline containing 15% by weight of DOP (dioctyl phthalate) was applied to the printed surface of the sample print, and after being left at 40°C for 24 hours, the vaseline was wiped off and the reflective optical density of the printed surface was measured. This was taken as the reflected optical density after the test. Plasticizer resistance is calculated using the following formula, and the larger the value, the better the plasticizer resistance.

(3) Lightfastness test First, the reflection optical density of the printed surface of the sample print to be used was measured, and this was taken as the reflection optical density before the test. Then,
The reflected optical density of the printed surface of the sample printed material was measured after irradiating the printed surface of the sample printed material with light from a fluorescent lamp (40 watts manufactured by Toshiba FL-40S/W) at 40°C for 168 hours from a distance of 10 cm. was taken as the reflected optical density after the test. Light resistance is calculated using the following formula, and the larger the value, the better the light resistance.

(4) Dark fading test First, the reflection optical density of the printed surface of the sample print to be used was measured before the test. Next, the sample print was
After being left in air at 0° C. for 168 hours, the reflective optical density of the printed surface was measured, and this was taken as the reflective optical density after the test. The dark fading property is calculated using the following formula, and the larger the value, the better the dark fading property is.

[Manufacture of receiving paper] Production Example 1 Silicone (Shin-Etsu Chemical Co., Ltd. KP-302, active ingredient 10%) was added and mixed to obtain a coating solution for forming a receptor layer.

[0039] This coating solution was applied onto polypropylene synthetic paper so that the dry coating film was about 5 g/m2.
A receiving paper with a receiving layer was produced by drying at 15°C for 15 minutes. Production Examples 2 to 8 Receiving papers having receptor layers were produced in the same manner as in Production Example 1 using the coating liquids for forming a receptor layer having the formulations shown in Table 1.

[0040]

[Table 1] [Preparation of printed matter] After cutting each of the eight types of receiving paper manufactured in Production Examples 1 to 8 into a predetermined size, a cyan test was applied on the receiving layer of each of these eight types of receiving paper. The pattern was sublimated thermal transfer printed using a video printer (VY-50) to obtain a printed matter. Example 1 A printed matter obtained by sublimation thermal transfer printing on the receiving layer of the receiving paper produced in Production Example 1 by the method shown in the above-mentioned method for producing printed matter was heat-treated in an oven at 120° C. for 1 minute. This heat-treated printed matter was used as a sample to determine the plasticizer resistance,
Three types of storage tests were conducted: light fastness and dark fading. The results are shown in Table 2. Comparative Example 1 A printed matter obtained by sublimation thermal transfer printing on the receiving layer of the receiving paper produced in Production Example 1 by the method shown in the production of printed matter above was used as a sample without heat treatment, and the plasticizer resistance and light resistance were evaluated. Three types of storage tests were conducted: color and dark fading. The results are shown in Table 2. Examples 2 to 8 The same procedure as Example 1 was carried out except that the receiving paper produced in Production Examples 2 to 8 was used. Examples 2 to 8 were obtained using the receiving papers manufactured in Production Examples 2 to 8, respectively. The results are shown in Table 2. Comparative Examples 2 to 8 Comparative Examples 2 to 8 were carried out in the same manner as in Example 1, except that the receiving papers produced in Production Examples 2 to 8 were used. Comparative Examples 2 to 8 used the receiving papers manufactured in Production Examples 2 to 8, respectively. The results are shown in Tables 2, 3 and 4.

[0041]
Table 2
Dye retention test results (%)
(Reflection optical density) Plasticizer resistance Light resistance
Dark fading comparative example 1 0.80
60 85 90 Example 1
0.82 92
91 93 Comparative Example 2 0.95
50 91 85 Example 2 0.96 91
95 89 Comparative Example 3 0
．． 84 60 92
92 Example 3 0.85
93 93 93

[0042]
Table 3
Dye retention test results (%)
(Reflection optical density) Plasticizer resistance Light resistance
Dark fading comparative example 4 0.89
60 95 94 Example 4
0.91 95
95 94 Comparative Example 5 0.95
59 98 98 Example 5 0.95 92
99 98 Comparative Example 6 1
．． 04 69 99
93 Example 6 0.96
92 90 98 Comparative Example 7
1.04 87
99 99

[0043]
Table 4
Dye retention test results (%)
(Reflection optical density) Plasticizer resistance Light resistance
Dark fading comparative example 8 0.95
65 85 97 Comparative example 9
1.07 13
90 95 Comparative Example 10 1.07
87 92 96 In addition, the dye detachment occurred when the printed surface of the printed matter that was not heat-treated was rubbed with a commercially available eraser and a fingernail, whereas the printed surface of the heat-treated printed matter was rubbed with either an eraser or a fingernail. No detachment of the dye was observed even by the following methods.

[0044]

Effects of the Invention According to the method of the present invention, the plasticizer resistance of printed images can be improved by simply heat-treating the printed matter obtained by sublimation type thermal transfer printing.
It is possible to provide a dye-sublimation thermal transfer printed matter that has improved light resistance, dark fading resistance, etc., and has excellent storage stability such as resistance to friction.

Claims (3)

[Claims] 1. After forming an image on the dye-receiving layer of a receiving paper by sublimation type thermal transfer printing, the dye-receiving layer is formed on a base sheet and includes a resin having film-forming ability. A method for producing a dye sublimation thermal transfer print with improved storage stability of a transferred image, the method comprising heat-treating a receiving paper on which an image has been formed. 2. The method according to claim 1, wherein the resin having film-forming ability comprises a resin having 18% by weight or more of vinyl acetate units. 3. The method according to claim 1, wherein the heat treatment is performed at a temperature of 100 to 200°C.