JP2001328359A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet having excellent feedability without thermal wrinkle while incorporating high storage stability. SOLUTION: In the thermal transfer sheet comprising a heat resistant lubricating layer 2 formed on one surface of a base sheet 1 and a thermal transfer dye layer 3 formed on the other surface, the layer 2 does not use a thermosetting resin to be reacted with a dimethylpolysiloxane but contains a thermoplastic resin in which two or more types of reactive modified dimethylpolysiloxanes to be reacted with each other are added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet using a sublimable dye (a heat transferable dye), and more particularly to a thermal transfer sheet for printing an image on an object to be transferred by a thermal head.

[0002]

2. Description of the Related Art A thermal transfer sheet used in a sublimation thermal transfer recording system is provided with a thermal transfer dye layer containing a sublimable (heat transferable) dye on one side of a base material, and a thermal transfer sheet and a thermal head on the other side. It has a structure in which a heat-resistant lubricating layer is provided in order to prevent fusing and to give smooth running properties to the thermal transfer sheet.

When printing on photographic paper with such a thermal transfer sheet, heat is applied from a thermal head to a heat-resistant lubricating layer,
The dye in the thermal transfer dye layer formed on the opposite surface is transferred to photographic paper.The color density is proportional to the amount of heat supplied from the thermal head, so the color density is changed by changing the surface temperature of the thermal head. Is changing. Therefore, in order to obtain a high-density transfer image, the surface temperature of the thermal head must be relatively high, and the temperature may reach several hundred degrees due to the recent demand for high-speed printing. As a result, fusion tends to occur between the thermal head and the heat-resistant lubricating layer, and the coefficient of friction between the thermal head and the heat-resistant lubricating layer increases, resulting in impaired good running properties of the thermal transfer sheet. In addition, there is a problem that the thermal transfer sheet is twisted to generate wrinkles called “thermal wrinkles”.

[0004] Therefore, in order to reduce the coefficient of friction between the heat-resistant lubricating layer of the thermal transfer sheet and the thermal head, especially at the time of high density printing where the surface temperature of the thermal head is relatively high, phosphorus is used as a lubricant. An acid ester, dimethylpolysiloxane, and the like are added to the heat-resistant lubricating layer.

[0005]

However, since most of the thermal transfer sheet is used in a roll state, the heat-resistant lubricating layer and the thermal transfer dye layer are always in contact with each other in the storage state, and are added to the heat-resistant lubricating layer. The above-mentioned lubricant migrated to the thermal transfer dye layer, and as a result, plasticized the thermal transfer dye layer,
There has been a problem in that crystallization of the dye is induced, the color density is changed, and the storage stability of the thermal transfer sheet is impaired.

In order to solve these problems, a thermosetting resin such as a polyisocyanate compound or an epoxy resin and a modified dimethylpolysiloxane capable of reacting with the thermosetting resin are added to the heat-resistant lubricating layer, and they are reacted and cured to form a thermal transfer resin. Attempts have been made to reduce the transfer of lubricant to the dye layer. However, the reactive dimethylpolysiloxane generally has insufficient compatibility with the organic resin, bleeds on the surface of the heat-resistant lubricating layer in a short time, and has not reacted with the thermosetting resin. Is left on the surface of the heat-resistant lubricating layer in a large amount, so that it is difficult to obtain a desired effect.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce the amount of unreacted dimethylpolysiloxane on the surface of a heat-resistant lubricating layer while maintaining the running property of a thermal transfer sheet. It is intended to enhance the storage stability of the thermal transfer sheet.

[0008]

Means for Solving the Problems The present inventors have added two or more reactive modified dimethylpolysiloxanes which can react with each other as a lubricant to a coating for forming a heat-resistant lubricating layer of a thermal transfer sheet. It has been found that the above object can be achieved by reacting and curing mutually reactive reactive modified dimethylpolysiloxanes bleeding on the surface during the formation of the compound, thereby completing the present invention.

That is, the present invention relates to a heat transfer sheet having a heat transfer dye layer on one side of a substrate sheet and a heat resistant slip layer on the other side of the substrate sheet, wherein the heat resistant slip layer is ,
A thermal transfer sheet comprising two or more reactive modified dimethylpolysiloxanes that have reacted with each other.

The present invention also relates to a method for producing this thermal transfer sheet, wherein a heat-resistant lubricating layer forming paint containing two or more reactive modified dimethylpolysiloxanes which can react with each other is coated on one surface of a substrate sheet. Provided is a production method characterized in that, when forming a heat-resistant lubricating layer by applying and drying, reactively modified reactive dimethylpolysiloxanes which have bleed on the surface of the heat-resistant lubricating layer and react with each other.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the thermal transfer sheet of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows a cross section of an example of the thermal transfer sheet of the present invention, and FIGS. 2 to 6 are top views thereof. Here, the heat-resistant lubricating layer 2 is provided on one side of the base sheet 1.
The other surface is provided with a thermal transfer dye layer 3 composed of at least a dye and a binder. Further, in addition to the thermal transfer dye layer 3, a sensor mark 4 for detecting a sheet position may be provided.

The heat-resistant lubricating layer 2 of the thermal transfer sheet according to the present invention reduces the amount of unreacted dimethylpolysiloxane on the surface of the heat-resistant lubricating layer while maintaining the running properties of the thermal transfer sheet, and improves the storage stability of the thermal transfer sheet. Therefore, it is constituted by a thermoplastic resin to which two or more reactive modified dimethylpolysiloxanes which can react with each other are added.

Examples of the reactive modified dimethylpolysiloxane capable of reacting with each other include a combination of an amino-modified dimethylpolysiloxane and an epoxy-modified dimethylpolysiloxane, a combination of a phenol-modified dimethylpolysiloxane and an epoxy-modified dimethylpolysiloxane, A combination of a phenol-modified dimethylpolysiloxane and a mercapto-modified dimethylpolysiloxane, a combination of a carboxyl-modified dimethylpolysiloxane and an epoxy-modified dimethylpolysiloxane, a combination of a mercapto-modified dimethylpolysiloxane and an epoxy-modified dimethylpolysiloxane, and the like can be given. .

When the amount of the reactive modified dimethylpolysiloxane is too small, the heat-resistant wrinkle property is reduced, and when the amount is too large, the storage stability is reduced. 5 to 10% by weight, more preferably 1.0 to
5.0% by weight.

It is preferable that the heat-resistant lubricating layer in the present invention does not use a thermosetting resin that reacts with dimethylpolysiloxane. As a result, compared to the case where a thermosetting resin is used, even if the addition amount of the reactive modified dimethylpolysiloxane is greatly reduced, a sufficient amount of reaction is required to ensure the desired storage stability and heat wrinkle resistance. The modified dimethylpolysiloxane can bleed on the surface of the heat-resistant lubricating layer.

The resin constituting the heat-resistant lubricating layer may be a heat-resistant resin having a glass transition temperature (Tg) of 80 ° C. or more, for example, polyvinyl, in order to prevent fusion between the thermal transfer sheet and the thermal head during image formation. Acetoacetal resin,
Examples include thermoplastic resins such as polystyrene, acrylonitrile-styrene copolymer which is a modified resin thereof, methacrylic resin represented by polymethyl methacrylate, acrylic resin, and polycarbonate.

If necessary, various additives such as various solid fillers and antistatic agents may be added to the heat-resistant lubricating layer 2 in order to prevent running in the printer and prevent sticking. Good.

The thickness of the heat-resistant lubricating layer 2 is usually 0.3-5 μm.
m.

The thermal transfer dye layer 3 of the thermal transfer sheet of FIG.
Yellow 3a, magenta 3 composed of dye and binder
b, cyan 3c, but the order of the colors does not necessarily have to be this order. Further, as shown in FIG. 3, the thermal transfer dye layer 3 may be composed of only black 5, and further, as shown in FIG. 4, may be composed of four colors of yellow 3a, magenta 3b, cyan 3c and black 5.

The thermal transfer sheet has a thermal transfer dye layer 3
In addition, as shown in FIG. 5, a transparent transfer protection layer 6 may be provided to transfer the image to the printing screen after printing to protect the printing screen. Further, as shown in FIG. 6, a transfer type receiving layer 7 for transferring to plain paper may be provided.

As the binder constituting the thermal transfer dye layer 3, a conventionally known thermoplastic resin for a binder can be used. For example, methyl cellulose, ethyl cellulose,
Cellulose-based resins such as hydroxyethylcellulose, hydroxypropylcellulose, and cellulose acetate; polyvinyl-based resins such as polyvinyl alcohol, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl acetate, and polystyrene; various urethane resins; and polyester resins.

The dye used in the thermal transfer dye layer 3 includes:
Conventionally known various dyes, for example, azo, disazo, methine, styryl, pyridone
Azo-based and the like, and mixed systems thereof, as magenta dyes, azo-based, anthraquinone-based, styryl-based, heterocyclic azo dyes and the like, and mixed systems thereof, and cyan dyes include anthraquinone-based, naphthoquinone-based, heterocyclic azo dyes, An indoaniline type and the like and a mixed type thereof can be used.

As the substrate sheet 1 of the thermal transfer sheet of the present invention, various conventionally known substrates can be used. For example, polyester films, polystyrene films, polypropylene films, polysulfone films, polycarbonate films, polyamide films, aramid films, and the like.

The thickness of the base sheet 1 is usually 1 to 30 μm.
m, preferably 2 to 10 μm.

The thermal transfer sheet of the present invention can be manufactured as described below.

First, a coating for forming a heat-resistant lubricating layer containing two or more reactive modified dimethylpolysiloxanes which can react with each other is applied to one surface of a base sheet material, and then dried. To form a heat-resistant lubricating layer. At this time,
It is necessary to react the reactive modified dimethylpolysiloxanes which have bleeded on the surface of the heat-resistant lubricating layer and which can react with each other. For this purpose, it is preferable to sufficiently bleed the reactive modified dimethylpolysiloxane on the surface of the heat-resistant lubricating layer. For example, a reactive modified dimethylpolysiloxane that can react even at a relatively low temperature (about 50 ° C.) is used. It is preferable to use and dry at about 50 ° C. for several days.

Thereafter, a thermal transfer dye sheet is formed on the other surface of the substrate sheet according to a conventional method, whereby a thermal transfer sheet can be manufactured.

Such a thermal transfer sheet of the present invention has excellent storage stability because the amount of unreacted dimethylpolysiloxane on the surface of the heat-resistant lubricating layer is reduced while maintaining sufficient running properties in the heat-resistant lubricating layer. Heat transfer sheet.

[0030]

EXAMPLES The thermal transfer sheet of the present invention will be specifically described below with reference to examples. Amount (parts) of each component in Examples
Are parts by weight.

Examples 1 to 6 and Comparative Examples 1 to 4 First, a method for producing a thermal transfer sheet will be described.

A 6 μm-thick polyester film (Lumirror, Toray Industries, Inc.) was used as a base sheet, and a heat-resistant lubricating layer forming paint composed of the composition shown in Table 1 was applied to a dry thickness of 0.5 μm, After curing for 5 days, a heat-resistant lubricating layer sheet used for evaluating the storage stability of the thermal transfer sheets of Examples 1 to 6 described below was obtained. Similarly, a coating for forming a heat-resistant lubricating layer composed of the composition shown in Table 2 was applied to a dry thickness of 0.5 μm and cured at 50 ° C. for 5 days, and the storage stability of the thermal transfer sheets of Comparative Examples 1 to 4 described later. A heat-resistant lubricating layer sheet to be used for evaluation of properties was obtained.

The two kinds of dimethylpolysiloxanes were added such that the functional group equivalents were equal.

Next, each of the heat-resistant lubricating layer sheets described above was newly prepared, and the back surface of each sheet was coated with the thermal transfer dye layer composition shown in Table 3 so as to have a dry thickness of 1 μm. To 6 and Comparative Examples 1 to 4 were obtained.

[0035]

[Table 1] Ingredients Parts by weight Polyvinyl butyral resin (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5.0 Dimethylpolysiloxane A Example Type (A (parts by weight)) 1 Amino-modified dimethylpolysiloxane ^{* 1} O.016 Ethoxy-modified Dimethylpolysiloxane ^{* 2} O.034 2 Amino-modified dimethylpolysiloxane ^{* 3} O.017 Ethoxy-modified dimethylpolysiloxane ^{* 4} O.033 3 Amino-modified dimethylpolysiloxane ^{* 1} O.031 Ethoxy-modified dimethylpolysiloxane ^{* 4} O.019 4 Amino-modified permethylpolysiloxane ^{* 3} O.031 Ethoxy-modified permethylpolysiloxane ^{* 2} O.019 5 Amino-modified permethylpolysiloxane ^{* 1} O.033 Ethoxy-modified permethylpolysiloxane ^{* 2} O.067 6 Amino-modified permethylpolysiloxane ^{* 3} O.035 Ethoxy-modified dimethylpolysiloxane ^{* 4} O.065 Silica (Nipsil E-200A, manufactured by Nippon Silica Industry Co., Ltd.) 0.5 Methyl ethyl ketone 47.25-A / 2 Toluene 47.25-A / 2 * 1: X-22-161AS, Shin-Etsu Chemical Co., Ltd. * 2: X-22-163A, Shin-Etsu Chemical Co., Ltd. * 3: X-22-161B, Shin-Etsu Chemical Co., Ltd. * 4: X- 22-163C, Shin-Etsu Chemical Co., Ltd.

[0036]

Table 2 Ingredients Parts by weight Polyvinyl butyral resin (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5.0 Dimethyl polysiloxane A Comparative example Type (A (parts by weight)) 1 Carbanol-modified dimethylpolysiloxane ^{* 5} O.05 2 Carbanol-modified permethylpolysiloxane ^{* 5} O.25 3 Amino-modified permethylpolysiloxane ^{* 6} O.05 4 Amino-modified permethylpolysiloxane ^{* 6} O.25 Isocyanate compound ^{* 7} 0.5 Silica (Nipsil E-200A, Nippon Silica Industry) 0.5 Methyl ethyl ketone 47-A / 2 Toluene 47-A / 2 * 5: X-22-160AS, Shin-Etsu Chemical Co., Ltd. * 6: KF-393, Shin-Etsu Chemical Co., Ltd. * 7: Coronate L, Japan Urethane Industry

[0037]

Table 3 Ingredients Parts by weight Dye (Disperse Violet 26) 5.0 Polyvinyl phthalate resin (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5.0 Methyl ethyl ketone 45.0 Toluene 45.0

(Evaluation) The thermal storage sheets of Examples 1 to 6 and Comparative Examples 1 to 4 were tested and evaluated for "storage stability" and "heat resistance wrinkle" as described below.

"Storage stability" The storage stability was evaluated using the change in the density of the thermal transfer dye layer as an index. That is, 2
Each heat transfer sheet having a size of 0 × 20 cm and the heat-resistant lubricating layer sheet are superimposed and 2.5 kg at a temperature of 40 ° C. by a press machine (PY-5EA type heating / cooling molding machine, Kodaira Seisakusho).
/ Cm ^{2 with} a load of 24 hours, and prints the pressed thermal transfer sheet and the initial state thermal transfer sheet on a special printing paper (UPC7010, manufactured by Sony Corporation) using a full-color printer (UP-7000, manufactured by Sony Corporation). The degree of change in the print density of the heat-transfer sheet subjected to the press treatment is compared with the print density of the thermal transfer sheet in the initial state, and measured by a Macbeth densitometer (TR-924). The sex was evaluated. Table 4 shows the results.
Shown in

(Evaluation Criteria for Storage Stability) Rank Criteria ○: Change in density is less than ± 5% (good storage stability) ×: Change in density is ± 5% or more (poor storage stability)

"Wrinkle resistance under heat" Regarding heat wrinkles, each thermal transfer sheet was cut and pasted on a magenta portion of a commercially available ink ribbon (UPC7010, manufactured by Sony Corporation), and a full-color printer (UP-7000, manufactured by Sony Corporation) was used. UPC701 at
A black solid print was made on a dedicated printing paper for No. 0, the presence or absence of hot wrinkles was visually determined, and the heat wrinkle resistance of the heat-resistant lubricating layer was evaluated according to the following evaluation criteria. Table 4 shows the obtained results.

(Evaluation criteria for heat wrinkle resistance) Rank criteria ○: No heat wrinkles occurred ×: Heat wrinkles occurred

[0043]

[Table 4]

From the results shown in Table 4, the heat-resistant lubricating layers of the thermal transfer sheets of the examples of the present invention did not show any wrinkles due to the increase in friction, and showed little change in the density of the thermal transfer dye layer.
It turns out that it shows the characteristic excellent in storage stability.

On the other hand, in Comparative Examples 2 and 4 in which the amount of dimethylpolysiloxane added was too large, the dimethylpolysiloxane could not completely react with the thermosetting resin and remained unreacted on the surface of the heat-resistant lubricating layer. In Comparative Examples 1 and 3, where the amount of change exceeded ± 5%, satisfactory results were not obtained. On the other hand, in Comparative Examples 1 and 3, although the amount of change in concentration was small, heat wrinkles were generated due to an increase in friction. It can be seen that a good result was not obtained.

From the above results, the heat-resistant lubricating layer does not use a thermosetting resin that reacts with dimethylpolysiloxane, but is composed of a thermoplastic resin using two or more reactive modified dimethylpolysiloxanes that can react with each other. This shows that the amount of unreacted dimethylpolysiloxane on the surface of the heat-resistant lubricating layer can be reduced while maintaining the running properties of the thermal transfer sheet, and the storage stability of the thermal transfer sheet can be improved.

[0047]

The thermal transfer sheet of the present invention has good storage stability and excellent running properties.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thermal transfer ink sheet of the present invention.

FIG. 2 is a top view of a thermal transfer ink sheet possible with the present invention.

FIG. 3 is a top view of a thermal transfer ink sheet possible with the present invention.

FIG. 4 is a top view of a thermal transfer ink sheet possible with the present invention.

FIG. 5 is a top view of a thermal transfer ink sheet possible with the present invention.

FIG. 6 is a top view of a thermal transfer ink sheet possible with the present invention.

[Explanation of symbols]

1 base sheet, 2 heat-resistant lubricating layer, 3 heat transfer dye layer,
4 sensor mark, 5 thermal transfer dye layer (black), 6
Transfer protective layer, 7 Transfer type receiving layer

Claims (4)

[Claims] 1. A thermal transfer sheet having a heat transfer dye layer on one side of a substrate sheet and a heat resistant slip layer on the other side of the substrate sheet, wherein the heat resistant slip layers react with each other. A thermal transfer sheet comprising two or more reactive modified dimethylpolysiloxanes as described above. 2. The thermal transfer sheet according to claim 1, wherein the heat-resistant lubricating layer does not contain a thermosetting resin capable of reacting with the reactive modified dimethylpolysiloxane. 3. The reactive modified dimethylpolysiloxane comprises:
3. The thermal transfer sheet according to claim 1, comprising an amino-modified dimethylpolysiloxane and an epoxy-modified dimethylpolysiloxane. 4. The method for producing a thermal transfer sheet according to claim 1, wherein a paint for forming a heat-resistant lubricating layer containing two or more reactive modified dimethylpolysiloxanes which can react with each other is applied to one surface of the base sheet. A method for producing a heat-resistant lubricating layer, which is applied and dried to react reactively modified dimethylpolysiloxanes bleeding on the surface of the heat-resistant lubricating layer and reacting with each other.