JP2540500B2 - Thermal transfer sheet - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a thermal transfer sheet for performing heating printing according to image information by a thermal head or the like.

[Background of the Invention]

In order to obtain an image according to image information using a thermal head, conventionally, thermosensitive coloring paper has been mainly used. In these thermosensitive color-developing papers, a colorless or pale-colored leuco dye provided on the base paper and a developer (for example, bisphenol A) react with each other when heated to obtain a colored image.

However, the above thermosensitive coloring paper has fatal drawbacks in that when the obtained image is stored for a long period of time, the color is erased or the non-image part is colored. Further, color printing is limited to two colors, and it is impossible to obtain a color image having continuous gradation.

On the other hand, as a recording method for improving the above-mentioned disadvantages,
A thermal transfer sheet provided with a heat-fusible wax layer in which a pigment or a dye is dispersed, or a thermal sublimation transfer sheet provided with a thermal sublimation transfer layer containing a heat transferable dye in a binder has been used in recent years. Has been started.

When the heat-melt transfer sheet and the transfer-target sheet are superposed and heat-printed from the back surface of the heat-transfer sheet, the heat-meltable wax layer containing the pigment or dye is transferred onto the heat-transfer target sheet to obtain an image. To be According to such a printing method, an image more durable than the heat-sensitive color-developing sheet can be obtained, and a multi-eating image can be obtained by sequentially printing the thermal transfer sheets containing the pigments or dyes of the three primary colors.

On the other hand, the thermal sublimation transfer sheet is formed by providing a binder layer containing a heat transferable dye on a sheet-shaped substrate,
When the obtained thermal transfer sheet and transfer target sheet are superposed on each other and heat printing is performed from the back surface of the thermal transfer sheet, only the dye in the binder layer is thermally sublimated and transferred onto the transfer target sheet to obtain an image. According to this printing method, a multicolor image can be obtained by sequentially printing the thermal sublimation transfer sheet containing the heat transfer dyes of the three primary colors.

In recent years, there has been an increasing demand for obtaining an image having a continuous tone such as a color photograph directly from an electric signal, and various attempts have been made.

One of these attempts is to obtain a silver salt color photograph directly from the CRT screen. This method has drawbacks in that running costs are high, and in the case of a 35 mm film, development processing is required after photographing, so that it is not immediacy.

As another method, an impact ribbon method or an inkjet method has been proposed, but it has a drawback that the image quality is poor and image processing is required, so that an image like a photograph cannot be easily obtained.

In order to solve such a drawback, an attempt has been made to perform recording using the above-mentioned thermal sublimation transfer sheet.
In the method using the thermal sublimation transfer sheet, the thermal transfer dye in the thermal sublimation transfer layer has a characteristic of transferring to the transfer target sheet according to the amount of thermal energy applied to the thermal transfer sheet, and therefore continuous gradation is obtained. An image having is obtained and can be recorded from a television signal by a simple process.

Capacitor paper, polyester film, polypropylene film, cellophane, cellulose acetate film and the like have been conventionally used as the substrate of such a thermal transfer sheet, and the thickness thereof is about 10 μm.

Of these substrates, capacitor paper is selected from the viewpoint of price, but emphasis is placed on such aspects as prevention of breakage during coating processing, ease of operation within the printer, thickness uniformity, and surface smoothness. Then, a plastic film is used, and among the plastic films, a polyester film has been preferably used in view of strength of thin paper.

By the way, in the case where a thermal sublimation transfer layer containing a thermal sublimation dye in a binder is provided on this polyester film, and heating printing is performed by a thermal head from the back surface of the film on which the thermal sublimation transfer layer is not provided. When the energy necessary for obtaining an image having a sufficient print density is applied to the back surface of the film, a so-called sticking phenomenon, in which the base sheet itself fuses with the thermal head, is observed, and the thermal transfer sheet becomes inoperable. Or, if it is significant, the sheet will break from that part.

In order to solve these problems, some attempts have been made to provide a heat-resistant protective layer on the back surface of the substrate sheet in the heat-fusion transfer sheet. Here are some examples:
A method for providing a metal oxide layer or a silicon oxide layer as a wear resistant layer on the back surface of the base (Japanese Patent Laid-Open Nos. 54-143152 and 57-57
-74195), a method of providing a heat resistant resin layer such as silicone or epoxy (JP-A-57-7467),
A method for providing a resin layer to which a solid or semi-solid surface active agent is added at room temperature (JP-A-57-12978) or a method for providing a layer in which a lubricating inorganic pigment is contained in a heat-resistant resin Japanese Laid-Open Patent Publication No. 56-155794) has been proposed.

The heat-resistant protective layer proposed by these heat-melt transfer sheets was provided on the back surface of the heat-sublimation transfer sheet to a thickness of about 3 μm, and printing was performed using a thermal head. In any case, the sticking phenomenon was observed. It could not function as a protective layer.

The reason for this is that the heat-resistant protective layer in the heat-melt transfer sheet is intended only for the melt-transfer sheet, and the heat energy required for the heat-melt transfer recording and the heat-sublimation recording using the sublimable dye are sufficient. When compared with the thermal energy for obtaining a high recording density, the fact that thermal sublimation recording requires about 1.5 times or more higher energy than thermal fusion transfer recording is mentioned.

In order to solve these problems, the present inventors have variously studied heat-resistant resins that can be used in thermal sublimation transfer sheets and systems in which a slipping substance is added to the resins, and the following tendency Found out.

In order to manufacture a thermal sublimation transfer sheet provided with a heat-resistant protective layer by a manufacturing process such as coating instead of an expensive process such as vapor deposition, it is necessary to use a resin having heat resistance as a base. . Also, in order not to deteriorate the thermal sensitivity to a polyester film of about 0.5 to 10 μm, the heat-resistant protective layer should have a thickness of about 0.5 to 3 μm. With this range of thickness, the thermal head should run on the thermal transfer sheet. To be possible, it is necessary to add some lubricant to the resin base. However, if a large amount of a conventionally known inorganic substance such as talc or mica is added to the resin base as the slipping substance to form the heat-resistant protective layer, the running is not smooth, and the solid part is rough,
Furthermore, this inorganic substance may adhere to the thermal head.

Further, since the thermal transfer sheet is generally wound and stored, the thermal transfer layer of the thermal transfer sheet and the back surface of the substrate sheet are in contact with each other. However, since the heat-resistant protective layer is provided on the back surface of the substrate sheet as described above, in the conventionally known heat-resistant protective layer, a serious problem that the dye present in the thermal transfer layer migrates into the heat-resistant protective layer. Was occurring.

Further, in a certain type of thermal transfer sheet, when the thermal transfer sheet is transferred by a print transfer device or the like, the thermal transfer sheet and a roll or the like in the apparatus may adhere to each other, which may cause a problem in running property of the thermal transfer sheet. there were.

Based on these experimental facts, the present inventors further studied, and as a result, by using a thermal transfer sheet provided with a heat-resistant layer and a heat-resistant slip layer made of specific components, the thermal head traveled smoothly during recording. Moreover, it is possible to provide a high-concentration image without roughness in the printing portion, and further, when the dye is transferred to the heat-resistant layer when wound and stored, the adhesion between the sheet and the roll in the transfer device is prevented. It has been found that a thermal transfer sheet that does not occur can be obtained.

[Outline of Invention]

The present invention is intended to solve the problems associated with the above conventional techniques, and has the following objects.

(A) To provide a thermal transfer sheet capable of running the thermal head without causing a sticking phenomenon even when heated by the thermal head to a temperature considerably higher than that of the thermal fusion transfer sheet.

(B) To provide a thermal transfer sheet that does not cause roughness in the printed portion.

(C) To provide a thermal transfer sheet having excellent storage stability without the dye in the thermal transfer layer migrating into the heat-resistant layer even when the thermal transfer sheet is wound and stored.

(D) To provide a thermal transfer sheet that does not adhere to a roll or the like of the thermal transfer sheet when the thermal transfer sheet is transferred by a print transfer device or the like, and thus has excellent transfer performance.

In order to achieve the above-mentioned object, the thermal transfer sheet of the present invention has a thermal transfer layer on one surface of the base material sheet, and (1) a synthetic resin that can be cured by heating on the other surface of the substrate sheet as a curing agent. A heat-resistant layer comprising (2) (a) a reaction product of (b) polyvinyl butyral and isocyanates, (b) an alkali metal salt or alkaline earth metal salt of phosphoric acid ester, and (c) a filler. The slip layer and the slip layer are laminated in this order.

Substrate sheet As the substrate sheet 1, condenser paper, polyester film, polyethylene naphthalate film,
A plastic film such as a polystyrene film, a polysulfone film, a polyimide film, a polyvinyl alcohol film, a cellophane, or an aramid (aromatic polyamide) film is used.
m, preferably 2 to 12 μm. These plastic films are preferable because they have a smooth surface and high mechanical strength, and among them, it is desirable to use a polyester film or an aramid film.

In the present invention, from the point of the invention, the base sheet is mainly made of a plastic film.In addition, when importance is placed on the price of the sheet itself and the heat resistance of the sheet itself, paper such as condenser paper is used. it can.

Thermal Transfer Layer The thermal transfer layer 2 is composed of a dye and a binder that are melted or sublimated by heating to be transferred.

The dye is preferably a sublimable disperse dye, a sublimable oil-soluble dye, or a sublimable basic dye, and has a molecular weight of
It is 150-800, preferably 350-700. These dyes are selected in consideration of the sublimation temperature, hue, weather resistance, solubility in the ink or the binder resin, and the like.

CI (abbreviation of chemical index, the same applies below) Yellow 51, Same 3, Same 54, Same 79, Same 60, Same 23, Same 7, Same 141, CI Disperse Blue 24, Same 56, Same 14, 14, Same 301 , Same 3
34, 165, 19, 19, 72, 87, 287, 154, 26, CI Disperse Red 135, 146, 59, 1, 1
73, 60, 167, CI Disperse Violet 4, 13, 13, 36, 5
6, the same 31, CI solvent violet 13, CI solvent black 3, CI solvent green 3, CI solvent yellow 56, the same 14, 16, 16, 29, CI solvent blue 70, the same 63, the same 36, the same 50 ,
49, 111, 105, 97, 11, CI Solvent Red 135, 81, 18, 18, 25, 1
9, 23, 24, 143, 146, 182.

As the binder of the thermal transfer layer, ethyl cellulose,
Cellulosic resins such as hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate, and vinyl resins such as polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, polyester, polyvinyl acetate, and polyacrylamide can be used. .

As an example of a more preferred binder, instead of the normal vinyl butyral resin described above, the molecular weight is 60,000 to 200,
000, the weight% of the vinyl alcohol portion is 10 to 40% in the polyvinyl butyral resin, preferably 15 to 30%, a special polyvinyl butyral resin having a glass transition point of 60 ° C to 110 ° C, preferably 70 ° C to 110 ° C. To be Glass transition point
When the temperature is lower than 60 ° C, the dye aggregates or precipitates over time, while when it exceeds 110 ° C, the dye is not sufficiently sublimated, which is not preferable. If the molecular weight is less than 60,000, the binding strength as a binder is insufficient, and 200,000
If it exceeds, the viscosity at the time of application becomes too high, which hinders application. If the vinyl alcohol portion is less than 10%, the thermal transfer layer will have insufficient stability over time, and therefore aggregation and precipitation of the dye and bleeding on the surface cannot be avoided. On the contrary, 40
When it exceeds%, the sublimation of the dye is hindered due to the affinity of the polyvinyl alcohol portion for the dye, and the printing density is lowered.

The weight ratio of the dye to the binder in the thermal transfer layer is preferably 0.3 or more of the dye / van inder, and when it is less than 0.3, the print density and thermal sensitivity are insufficient. On the other hand, when the amount of the dye / binder exceeds a few, the retention of the dye in the binder becomes insufficient and the storability of the thermal transfer sheet deteriorates.
Therefore, the dye / binder is preferably 0.3 to 2.3, more preferably 0.55 to 1.5.

The dye is preferably dissolved in the binder of the thermal transfer layer. In conventional sublimation transfer papers for textiles, the dye is dispersed in the binder, so in order to sublimate the dye, energy is exerted to overcome the interaction between the dye molecules and the interaction between the dye molecule and the binder. As a result of needing and inevitably high energy,
Thermal sensitivity decreases. In this respect, it is advantageous in terms of thermal sensitivity that the dye is dissolved in the binder.

The thermal transfer layer may be formed by selecting a dye so that a desired hue can be transferred when printed, and if necessary, two or more thermal transfer layers having different dyes are arranged side by side on a thermal transfer sheet. For example, when forming an image such as a natural color photograph by repeating the printing of corner colors according to the color separation signal, it is desirable that the hue when printing is the corner colors of cyan, magenta, and yellow. Line up the three thermal transfer layers containing the dye that gives the dye. Alternatively, in addition to cyan, magenta, and yellow, a thermal transfer layer containing a dye that imparts a hue of black may be added. It is preferable to provide a mark for position detection at the same time when any one of the thermal transfer layers is formed during the formation of these thermal transfer layers, because an ink and a printing step different from the thermal transfer layer formation are not required.

Heat-Resistant Layer It is preferable to provide the heat-resistant layer 3 separately from the heat-resistant slip layer 4 described below in order to improve the heat resistance of the thermal transfer sheet.

Other types of combinations can be used as the heat-curable synthetic resin that can be cured by heating and its curing agent. Typical examples are polyvinyl butyral and polyvalent isocyanate, acrylic polyol and polyvalent isocyanate, cellulose acetate and titanium chelating agent, and polyester and organic titanium compound. The following table shows the names of products and the amounts (parts by weight) to be blended, including those that are easily available on the market.

It may be preferable to add an extender to the above synthetic resin. Examples of extender pigments suitable for this purpose are magnesium carbonate, calcium carbonate, silica, clay, titanium oxide and zinc oxide. Usually, the compounding amount is suitably 5 to 40% of the resin on a weight basis. It is preferable that the additive mixing is carried out by using a three-roll mill or a sand mill to achieve sufficient dispersion.

If the adhesive strength of the heat-resistant layer to the base film is insufficient,
It is advisable to use appropriate primers.

By the way, in general, a component that imparts lubricity (slippage) to a sheet surface and a component that imparts heat resistance tend to cancel each other out. For example, in the heat-resistant slip layer 4,
When the lubricating component increases, the heat resistance decreases. Therefore,
In order to obtain good heat resistance, the thickness of the heat resistant slip layer must be increased. In order to avoid this problem, it is preferable that the heat-resistant layer 3 and the heat-resistant slip layer 4 are provided in a laminated manner.
Both lubricity and heat resistance can be improved at the same time, and (b) as a result, the film thickness can be reduced.

Heat-resistant slip layer The heat-resistant slip layer 4 imparts appropriate slipperiness (sliding) to the surface of the sheet, and prevents thermal fusion between the thermal head and the thermal transfer sheet (sticking phenomenon) to improve the running property of the sheet. It is extremely important in making it happen.

The heat-resistant slip layer is composed of (a) a reaction product of polyvinyl butyral and isocyanates, (b) a layer mainly containing an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester, (c) and a filler.

Polyvinyl butyral reacts with isocyanates to form a resin having good heat resistance. As polyvinyl butyral, those having as high a molecular weight as possible and containing a large amount of --OH groups which are reaction sites with isocyanates are preferable. Particularly preferred is polyvinyl butyral having a molecular weight of 60,000 to 200,000 and a glass transition temperature of 60.
~ 110 ℃, containing 15% by weight of the vinyl alcohol portion
~ 40%.

Examples of the isocyanates used in forming the heat resistant slip layer include polyisocyanates such as diisocyanate and triisocyanate, which may be used alone or in combination. Specifically, the following compounds are exemplified. Paraphenylene diisocyanate, 1-chloro-2,4-phenyldiisocyanate,
2-chloro-1,4-phenyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, 4,4'-biphenylene diisocyanate, triphenylmethane triisocyanate, 4,4 ', 4 "-Trimethyl-3,3 ', 2'-triisocyanate-2,4,6-triphenylcyanurate and the like.

Isocyanates for polyvinyl butyral,
It is usually used in an amount of about 1 to 100% by weight, preferably about 5 to 60% by weight.

The alkali metal salt or alkaline earth metal salt of phosphoric acid ester has a function of imparting lubricity to the heat resistant slip layer, and Gafac RD720 manufactured by Toho Kagaku Co., etc. is used.
The alkali metal salt or alkaline earth metal salt of the phosphoric acid ester is used in an amount of 1 to 50% by weight, preferably 10 to 40% by weight, based on polyvinyl butyral. Since alkali metal salts or alkaline earth metal salts of phosphoric acid esters are added as lubricants in the state of being dissolved in the binder in a molecular form, compare with the case of adding solid lubricants such as mica or talc. As a result, there is an advantage that the printing portion does not have roughness.

As the alkali metal salt or alkaline earth metal salt of the phosphoric acid ester, a sodium salt of the phosphoric acid ester is particularly preferable, and one example thereof is represented by the following general formula.

(In the formula, R is an alkyl group having 8 to 30 carbon atoms or an alkylphenyl group, and n is the average number of moles of ethylene oxide added.) Alkali metal salts or alkaline earth metal salts of phosphoric acid esters correspond to Phosphoric acid ester (not salt)
As compared with the former, when the former shows a pH of 5 to 7 when dissolved in water, and the latter shows a pH of 2.5 or less, as can be seen,
Less acidic than the corresponding phosphate ester. By the way, as described above, polyvinyl butyral and isocyanates react to form the base of the heat resistant slip layer, but this reaction is difficult to proceed in a strong acidic region, the reaction takes time, and the degree of crosslinking itself is low. turn into. Therefore, in the reaction system of polyvinyl butyral and isocyanates, phosphate ester (not in salt form)
When added, the reaction between the two takes a remarkably long time, and the cross-linking degree of the obtained reaction product is unavoidably low. On the other hand, in the reaction between polyvinyl butyral and isocyanates, when an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester is added,
It is possible to obtain a product in which the reaction of the both proceeds rapidly and the degree of crosslinking is large. Therefore, a thermal transfer sheet having a heat-resistant slip layer obtained by adding an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester to a reaction system of polyvinyl butyrate and isocyanates can be wound and stored. It is considered that the dye in the thermal transfer layer does not migrate into the heat resistant slip layer.

When an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester is used as a slippery agent in the heat resistant slip layer, even if the thermal transfer layer and the heat resistant slip layer are in close contact with each other, the alkali metal salt of the phosphoric acid ester or There is also an advantage that the alkaline earth metal salt does not migrate to the thermal transfer layer at all and no contamination of the thermal transfer layer is observed.

As the filler, clay, talc, zeolite, aluminosilicate, calcium carbonate, Teflon powder,
An inorganic or heat-resistant organic filler such as zinc oxide, titanium oxide, magnesium oxide, silica, carbon, or a condensate of benzoguanamine and formaldehyde may be used.

The filler has an average particle size of 3 μm or less, preferably 0.1 μm or less.
It is desirable that it is ˜2 μm. Further, the filler is preferably 0.1 to 25% by weight with respect to polyvinyl butyral.
Used in an amount of 1.0 to 10% by weight.

By using such a filler in the heat-resistant slip layer, fusion between the thermal head and the thermal transfer sheet is reduced, and so-called sticking phenomenon is not observed at all.

To provide the heat-resistant slip layer on the base sheet 1, the above components are dissolved in a suitable solvent to form a heat-resistant slip layer-forming ink, which is formed on the base sheet 2 by an appropriate printing method and coating method. Then, by heating at a temperature of 30 to 80 ° C., the polyvinyl butyral and the isocyanates may be reacted with each other to form a heat resistant protective film.

At this time, the filler is preferably kneaded with an alkali metal salt or alkaline earth metal salt of a phosphate ester in advance to prepare a filler kneaded dispersion composition.

The heat-up slip layer has a thickness of 0.5 to 5 μm, preferably 1 to 5 μm.
It preferably has a thickness of 2 μm. This film thickness is 0.5
When the thickness is smaller than μm, the effect as a heat-resistant slip layer is not sufficient, and when the thickness is larger than 5 μm, heat transfer from the thermal head to the sublimation transfer layer becomes poor, resulting in a disadvantage that the print density is lowered.

As described above, by forming the heat resistant slip layer with (a) a reaction product of polyvinyl butyral and isocyanates, (b) an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester, and (c) a filler. A heat-resistant slip layer having sufficiently excellent performance can be obtained, but in some cases, when a thermal transfer sheet having such a heat-resistant slip layer is transferred inside a print transfer device or the like, tension or thermal force applied to the thermal transfer sheet is increased. Depending on the print pressure of the head, a problem may occur in the transportability of the thermal transfer sheet.

In such a case, it is preferable to add a phosphate ester that is not in the salt form (d) to the heat resistant slip layer, in addition to the components (a), (b) and (c).
As the phosphoric acid ester not in the salt form, those not in the salt form of the phosphoric acid ester represented by the above-mentioned alkali metal salt or alkaline earth metal salt of the phosphoric acid ester are used,
Specifically, Prysurf A208S manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. and GAFAC RS710 manufactured by Toho Kagaku Co., Ltd. may be used.

The phosphate ester not in such a salt form is 1 to 50% by weight, preferably 1 to 50% by weight, based on polyvinyl butyral.
Used in an amount of 30% by weight. When it exceeds 50% by weight, it is not preferable because the dye or pigment in the thermal transfer layer is transferred to the heat-resistant slip layer, particularly when stored in a stacked or rolled state.

The heat-resistant slip layer is mainly composed of the above components, but in order to prevent blocking in the wound state,
A small amount of particulate matter such as talc, silica, calcium carbonate, and Teflon powder may be added.

The order of providing the heat transfer layer 2, the heat resistant layer 3 and the heat resistant slip layer 4 on the base material sheet 1 is preferably heating in order to promote the reaction between polyvinyl butyral and isocyanate, and the effect of heat on the heat transfer layer during this heating. In order to prevent this, it is preferable to provide the heat resistant slip layer 4 on the base material sheet 2 and then provide the thermal transfer layer 2.

By providing the heat resistant slip layer, the following effects are produced.

(A) The sticking phenomenon does not occur even when heated to a temperature considerably higher than that of the thermal head.

(B) Roughness does not occur in the printed part.

(C) Even when the thermal transfer sheet is wound and stored, the dye in the thermal transfer layer does not migrate into the heat resistant slip layer, and therefore the storage stability is excellent.

(D) When the thermal transfer sheet is transferred by a print transfer device or the like, the thermal transfer sheet and the roll do not adhere to each other, and therefore the transfer performance is excellent.

Example of Invention

Example 1 A heat-resistant layer ink composition I having the composition (parts by weight) shown below was prepared and used as a base film.
Polyethylene terephthalate film "S-PET"
(Toyobo Co., Ltd.), after applying using Miyabar # 8,
Dry with warm air.

(Ink composition I for heat-resistant layer) Polyvinyl butyral resin "S-REC BX-1" (manufactured by Sekisui Chemical) 4.5 parts Toluene 45 parts Methyl ethyl ketone 4.5 parts Diisocyanate "Takenate D-110N" (manufactured by Takeda Chemicals) 2.0 parts 75% ethyl acetate solution Next, a heat-resistant slip layer ink composition I having the following composition was prepared, and the heat-resistant layer ink composition I was applied and then applied with a miya bar # 6 so as to be overlapped and dried with warm air.

(Heat-resistant slip layer ink composition I) Polyvinyl butyral resin "ESREC BX-1" 5.7 Toluene 43.1 Methyl ethyl ketone 43.1 Phosphate ester "Prysurf A-208S" (Daiichi Kogyo Seiyaku Co., Ltd.) 1.3 Phosphate ester sodium salt 1.7 "GAFAC RD720 "(Toho Kagaku) 1.7 Talc" Microace L-1 "(Nippon Talc) 1.2 Amine catalyst" Desmorapid PP "(Sumitomo Bayer Urethane) 0.1 Diisocyanate" Coronate L 45% ethyl acetate solution "
(Manufactured by Nippon Polyurethane) 3.8 The film was further cured by heating at 60 ° C. for 12 hours in an oven. The amount of ink applied after drying is about 1.
It was ² g / m ² .

Separately, an ink composition for forming a thermal sublimation transfer layer having the following composition was prepared, and the surface of the base film opposite to the heat resistant layer was coated with Miyabar # 10 and dried with warm air. The coating amount of this transfer layer was about 1.2 g / m ² .

(Thermal sublimation transfer ink) Disperse dye (Nippon Kayaku Kayaset Blue 714) 4 parts by weight Polyvinyl butyral (Sekisui Chemical S-REC BX-1)
4.3 parts by weight Toluene 40 parts by weight Methyl ethyl ketone 40 parts by weight Isobutanol 10 parts by weight On the other hand, a synthetic paper "YUP" with a thickness of 150 μ is used as a base film.
Using “O-FPG150” (manufactured by Oji Yuka Co., Ltd.), an ink for forming an image receiving layer having the following composition was applied with a wire bar # 36 so that the coating amount when dried was 4.0 g / m ^{2, to} obtain a heat transferable sheet.

(Ink for forming image-receiving layer) Polyester resin "Vylon 200" (Toyobo) 5 parts by weight Polyester resin "Vylon 290" (Toyobo) 5 parts by weight Amino-modified silicone oil (Shin-Etsu Chemical Co., Ltd.) 0.5 parts by weight Epoxy-modified silicone oil (Shin-Etsu Chemical Co., Ltd.) 0.5
Parts by weight Toluene 44.5 parts by weight Methyl ethyl ketone 44.5 parts by weight The thermal sublimation transfer sheet obtained as described above and the thermal transfer sheet are stacked so that the thermal transfer layer and the receiving layer are in contact with each other,
Recording was performed with a thermal head from the heat resistant layer side. Recording conditions are output: 1 W / dot, pulse width: 0.3-4.5 m sec,
Dot density: 3 dots / mm.

No sticking phenomenon occurred and no wrinkles occurred, and the thermal transfer sheet ran smoothly. When the print density was measured with "Macbeth Densitometer RD-918", the reflection density of the high-density color-developed part with a pulse width of 4.5 msec was 1.70,
Also, the pulse width of 0.3 msec was 0.16, and the gradation was recorded according to the applied energy.

Printing was attempted under the same conditions.

Example 2 The following ink composition was prepared and applied on the same polyester base film as in Example 1.

(Ink composition II for heat-resistant layer) Acrylic polyol "Acrit 6416MA 45% solution" (manufactured by Taisei Kako) 41.2 parts by weight Toluene 26.3 parts by weight Methyl ethyl ketone 26.3 parts by weight Diisocyanate "Coronate L 45% acetic acid ester solution" (Nippon Polyurethane Products) 6.2 parts by weight Next, the heat-resistant slip layer ink composition I was applied onto the heat-resistant layer in the same manner as in Example 1 and heat-cured, and then the heat-sensitive sublimation transfer layer was applied in the same manner. Printing was performed under the same conditions by superimposing it on the thermal transfer sheet.

In this case also, no sticking phenomenon or wrinkle was observed, and the solid portion was not roughened, and good printing was possible.

Example 3 A thermal transfer sheet was prepared in the same manner as in Example 2 except that the following ink composition was used in which the talc in the heat resistant slip layer ink composition I was replaced with calcium carbonate, and printing was performed under the same conditions.

(Ink composition II for heat-resistant slip layer) Polyvinyl butyral resin "ESREC BX-1" 5.7 parts by weight Toluene 43.1 parts by weight Methyl ethyl ketone 43.1 parts by weight Phosphate ester "Prysurf A-208S" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 1.3 parts by weight Sodium phosphate ester "GAFAC RD720" (manufactured by Toyo Kagaku) 1.7 parts by weight Calcium carbonate "Shiragika DD" (manufactured by Shiraishi Calcium) 1.2
Parts by weight Amine-based catalyst "Desmorapid PP" (Sumitomo Bayer Urethane) 0.1 parts by weight Diisocyanate "Coronate L 45% ethyl acetate solution"
(Manufactured by Nippon Polyeletan) 3.8 parts by weight In this case as well, the sticking phenomenon and the occurrence of wrinkles were not required, and good printing was achieved.

Example 4 Similarly, in the above ink composition for heat-resistant slip layer, as a filler, aluminosilicate, clay, zeolite, Teflon powder, zinc oxide, magnesium oxide,
A thermal transfer sheet was prepared in the same manner as in Example 2 except that a condensate of titanium oxide, silica, carbon, benzoguanamine and formaldehyde was used, and printing was performed under the same conditions.

Also in this case, the sticking phenomenon and the occurrence of wrinkles were not required, and good printing was possible.

Example 5 A thermal transfer sheet was prepared in the same manner as in Example 1 except that the following ink composition containing calcium carbonate was prepared as the ink for the heat-resistant layer, and printing was performed under the same conditions.

(Ink composition for heat-resistant layer III) Acrylic polyol "Acryt 6416MA 45% solution" (manufactured by Taisei Kako) 41.2 parts by weight toluene 23.5 parts by weight Methyl ethyl ketone 25.0 parts by weight Diisocyanate "Coronate L 45% acetic acid ester solution" (manufactured by Nippon Polyurethane) 7.5 parts by weight Calcium carbonate (Shiragana DD) (made by Shiraishi calcium) 2.8
By weight In this case also, no sticking phenomenon or wrinkle was observed and good printing was achieved.

Example 6 Instead of calcium carbonate, amino silicate, clay, talc, zeolite, as a filler for the ink for heat-resistant layer,
A thermal transfer sheet was prepared in the same manner as in Example 5 except that Teflon powder, zinc oxide, magnesium oxide, titanium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde were used, and printing was performed under the same conditions. In this case as well, the sticking phenomenon and the generation of wrinkles were not required, and good printing was possible.

[Brief description of drawings]

The accompanying drawings are cross-sectional views of the thermal transfer sheet according to the present invention. 1 ... Base material sheet, 2 ... Thermal transfer layer, 3 ... Heat-resistant layer, 4
…… Heat-resistant slip layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 61-14991 (JP, A) JP 59-174392 (JP, A) JP 58-171992 (JP, A) JP 56- 155794 (JP, A) Japanese Patent Publication 4-79317 (JP, B2)

Claims (6)

(57) [Claims] 1. A heat transfer layer on one surface of a base sheet,
On the other surface, (1) a heat-resistant layer obtained by curing a synthetic resin that can be cured by heating with a curing agent, and (2) (a) a reaction product of polyvinyl butyral and isocyanates, (b) phosphoric acid Alkali metal salt or alkaline earth metal salt of ester and (c) filler (however, the content of the filler is based on the amount of polyvinyl butyral)
A heat-resistant slip layer composed of 0.1 to 25% by weight) is laminated in this order. 2. A synthetic resin and a curing agent, which form a heat-resistant layer and can be cured by heating, are (a) polyvinyl butyral and a polyvalent isocyanate, (b) an acrylic polyol and a polyvalent isocyanate, and (c) a cellulose acetate. The thermal transfer sheet according to claim 1, which is selected from a combination of a titanium chelating agent and (d) polyester and an organic titanium compound. 3. A particulate material selected from the group consisting of calcium carbonate, talc amino silicate, clay, zeolite, Teflon powder zinc oxide, magnesium oxide, titanium oxide, silica carbon, and a condensate of benzoguanamine and formaldehyde in the heat resistant layer. The thermal transfer sheet according to claim 1, which is used. 4. The filler used in the heat-resistant slip layer is composed of calcium carbonate, talc, aluminosilicate, clay, zeolite, Teflon powder, zinc oxide, magnesium oxide, titanium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde. The thermal transfer sheet according to claim 1, which is selected from the group. 5. The thermal transfer sheet according to claim 1, wherein the thermal transfer layer is a thermal sublimation transfer layer comprising a heat transferable dye and a binder resin. 6. The thermal transfer sheet according to claim 1, wherein the thermal transfer layer is a thermal melt transfer layer composed of a dye or pigment and wax.