JPS62259889A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a high density image generating no roughness in a printed part while smoothly running a thermal head at the time of recording, by providing a heat resistant layer and a heat resistant slip layer both of which comprise specific components, to a thermal transfer sheet. CONSTITUTION:A thermal transfer sheet is constituted by a method wherein a thermal transfer layer 2 is provided to one surface of a base material sheet 1 and a heat resistant layer 3 formed by curing a synthetic resin in the presence of a curing agent under heating and a heat resistant slip layer 4 consisting of a reaction product of polyvinyl butyral and isocyanates, an alkali metal or alkaline earth metal salt of phosphoric ester and a filler are laminated to the other surface of said sheet 1 in this order. As the synthetic resin and curing agent constituting the heat resistant layer, there is polyvinyl butyral and multivalent isocyanate or polyester and an organotitanium compound. As isocyanates used in forming the heat resistant slip layer, polyisocyanates such as diisocyanate, triisocyanate or the like are designated and, as the alkali metal or alkaline metal salt of phosphoric ester, a sodium salt of phosphoric ester is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal transfer sheet for performing thermal printing according to image information using a thermal head or the like.

[Background of the invention]

Conventionally, thermosensitive coloring paper has been mainly used to obtain an image according to image information using a thermal head. These thermosensitive coloring papers contain a leuco dye that is colorless or light colored at room temperature and a color developer (e.g. bisphenol A) provided on the base paper.
A colored image is obtained through a contact reaction when heated.

However, the above-mentioned thermosensitive coloring paper has a fatal drawback in that if the obtained image is stored for a long period of time, the color may fade too much or the non-image areas may develop color. Furthermore, color printing is limited to two colors, making it impossible to obtain color images with continuous gradations.

On the other hand, as a recording method to improve the above-mentioned drawbacks, a thermal transfer sheet in which a heat-melting wax layer in which pigments or dyes are dispersed is provided on a sheet-like substrate, or a thermal transfer sheet in which a heat-transferable dye is contained in a binder. Heat sublimation transfer sheets provided with a sublimation transfer layer have recently begun to be used.

This heat-melting transfer sheet and transfer sheet are overlapped,
When thermal printing is performed from the back side of the thermal transfer sheet, a thermal FB fusible wax layer containing a pigment or dye is transferred onto the thermal transfer sheet to obtain an image. According to such a printing method, an image that is more durable than a heat-sensitive coloring sheet can be obtained, and a multicolor image can be obtained by sequentially printing a thermal transfer sheet containing pigments or dyes of three primary colors.

On the other hand, a heat sublimation transfer sheet is formed by providing a single layer of a binder containing a heat-transferable dye on a sheet-like substrate.
When the smoothed thermal transfer sheet and the transfer sheet are superimposed and thermal printing is performed from the back side of the thermal transfer sheet, only the dye in the binder layer is thermally sublimated and transferred onto the transfer sheet to obtain an image. Even with this printing method, a multicolor image can be obtained by sequentially printing heat sublimation transfer sheets containing heat transferable dyes of three primary colors.

Incidentally, in recent years, there has been an increasing demand for obtaining continuous gradation images such as color attenuation directly from electrical signals, and various attempts have been made.

One of these attempts is to obtain silver halide color photographs directly from the CR7 screen. This method has drawbacks such as high running costs and lack of immediacy since 35M film requires post-photography processing.

As another method, an impact ribbon method or an inkjet method has been proposed, but these methods have the disadvantage that the image quality is poor, other processing is required, and it is not possible to easily obtain an image with faded appearance.

In order to solve these drawbacks, attempts have been made to perform recording using the above-mentioned thermal sublimation transfer sheet i-.

This method using a thermal dye sublimation transfer sheet has the characteristic that the thermal transfer dye in the thermal W color transfer layer transfers to the transfer sheet in accordance with the thermal energy applied to the thermal transfer sheet. An image with a tone can be obtained, and
It is possible to record TV signals with simple processing.

Condenser paper, polyester film, polypropylene film, cellophane, cellulose acetate film, and the like have been conventionally used as substrates for such thermal transfer sheets, and those having a thickness of about 10 μm are used.

Among these substrates, capacitor paper is selected from the viewpoint of price, but emphasis is placed on prevention of breakage during coating processing, ease of operation in the printer, uniformity of thickness, and smoothness of the surface. If this is the case, a plastic film is used, and among the plastic films, polyester film has been preferably used because of its strength when used with tissue paper.

By the way, a thermal sublimation transfer layer containing a thermal dye in a binder was provided on this polyester film, and thermal printing was performed with a thermal head from the back side of the film where the thermal sublimation transfer layer was not provided. In this case, when the energy necessary to obtain an image with sufficient print density is applied to the back side of the film, a so-called sticking phenomenon is observed in which the base sheet itself fuses with the thermal head, making it impossible for the thermal transfer sheet to run. If the damage is severe, the sheet will break from that part.

In order to solve these problems, several attempts have been made to provide a heat-resistant protective layer on the back side of a base sheet in heat-melting transfer sheets. Some examples include a method of providing a silicon oxide layer as a metal layer or a wear-resistant layer on the back surface of the base (Japanese Patent Application Laid-open Nos. 54-143152 and 57-74195), silicone or epoxy, etc. Method of providing a heat-resistant resin layer (JP-A-57-
7467), a method of providing a resin layer containing a solid or semi-solid surfactant at room temperature (Japanese Patent Laid-Open No. 57-1
2978@publication) or a method of providing a layer containing a slippery non-slip pigment in a heat-resistant resin (JP-A-56-15579)
Publication No. 4) have been proposed.

When the heat-resistant S layer proposed for these heat-melting transfer sheets was provided on the back side of the heat-sublimation transfer sheet to a thickness of about 3μ and printed using a thermal head, a sticking phenomenon was observed in all cases. Therefore, it could not function as a protective layer sufficiently.

The reason for this is that the heat-resistant protective layer in the above-mentioned heat-melt transfer sheet is intended for heat-melt transfer sheets, and the heat energy required for heat-melt transfer recording and heat sublimation recording using sublimable dyes are Comparing the thermal energy required to obtain sufficient recording density, the fact is that thermal sublimation recording requires about 1.5 times or more energy than thermal melt transfer recording.

In order to solve these problems, the present inventors further investigated various heat-resistant resins that can be used in thermal sublimation transfer sheets, as well as systems in which a slippery substance is added to the resin, and found the following trends. I found out.

In order to manufacture thermal sublimation transfer sheets with a heat-resistant protective layer through a manufacturing process such as coating, rather than through expensive processes such as vapor deposition, it is necessary to use a heat-resistant resin as a base. . Also 0,5~10μ
In order not to deteriorate the thermal sensitivity of a polyester film of about 100 to 100 µm, the appropriate thickness of the heat-resistant protective layer is about 0.5 to 3 μm, and a thickness within this range allows the thermal head to run on the thermal transfer sheet. In order to do this, it is necessary to add some lubricating substance to the resin base. However, if a heat-resistant protective layer is formed by adding multiple previously known inorganic substances such as talc and mica to a resin base as these lubricating substances, the running will not be smooth, the solid area will be rough, and the thermal head may become damaged. This inorganic substance may adhere.

In addition, since thermal transfer sheets are generally stored rolled up,
The thermal transfer layer of the thermal transfer sheet and the back surface of the base sheet are in contact with each other.

However, since the heat-resistant protective layer is provided on the back side of the base sheet as described above, the conventional heat-resistant protective layer has the serious problem of dye existing in the thermal transfer layer migrating into the heat-resistant "A" layer. A problem had arisen.

Furthermore, with some types of thermal transfer sheets, when the thermal transfer sheet is transported by a printing transfer device, the thermal transfer sheet and the inner roll of the packaging may adhere to each other, causing problems with the running properties of the thermal transfer sheet. was there.

Based on these experimental facts, the present inventors conducted further research and found that by using a thermal transfer sheet provided with a heat-resistant layer and a heat-resistant slip layer made of specific components,
During recording, the thermal head runs smoothly and provides a high-density image with no roughness in the printed area.Moreover, when the dye is rolled up and stored, there is no migration of dye into the heat-resistant layer, and there is no dye transfer inside the transfer device. It has been found that a thermal transfer sheet can be obtained in which the sheet does not adhere to a roll or the like.

[Summary of the invention]

This clarification is intended to solve the problems associated with the prior art as described above, and has the following objectives.

(a) To provide a thermal transfer sheet that can be run by a thermal head without causing a sticking phenomenon even when heated by a thermal head to a considerably higher temperature than a thermal melting transfer sheet.

(b) To provide a thermal transfer sheet that does not have roughness even in the printed area.

(C) To provide a thermal transfer sheet that does not transfer dye in a thermal transfer layer into a heat-resistant layer even when the thermal transfer sheet is wound up and stored, and therefore has excellent storage stability.

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

In order to achieve the above objects, the thermal transfer sheet of the present invention has a thermal transfer layer on one side of a base sheet, and on the surface to be used, (1) a synthetic resin that hardens when heated. A heat-resistant layer cured with a curing agent, (2) (a) a reaction product of polyvinyl butyral and isocyanates, (b) an alkali metal salt or alkaline earth metal salt of a phosphoric acid ester, and (c) a filler. The heat-resistant slip layer is stacked in this order.

Base material sheet The base material sheet 1 includes plastic films such as condenser paper, polyester film, polyethylene naphthalate film, polystyrene film, polyt-Nalfone film, polyimide film, polyvinyl alcohol film, cellophane, and aramid (aromatic polyamide) film. used, and the thickness is 2 to 50
μm1 is preferably 2 to 12 μm. These plastic films are preferred because they have a smooth surface and high mechanical strength, and among them, polyester films and aramid films are preferably used.

In the present invention, from the perspective of the invention, the base sheet is mainly a plastic film, but in addition, the price of the sheet itself and the heat resistance of the sheet itself are important factors (6). Can be used.

Thermal Transfer Layer The thermal transfer layer 2 is composed of a dye and a binder that are transferred by melting or sublimation when heated.

The dye is preferably a sublimable disperse dye, a sublimable oil-soluble dye, or a sublimable basic dye, and has a molecular weight of 1.
50-800. Preferably it is 350-700. These dyes are selected in consideration of sublimation temperature, hue, weather resistance, solubility in ink or binder resin, etc., and include, for example, the following dyes.

C,1, (abbreviation for chemical index, hereinafter b
@ji) Yellow 51, 3, 54, 79, 60.
23, 7, 141, C11, Disperse Blue 24, 56, 14, 301, 334, 165
, 19, 72, 87, 287, 154, 2
6, C, 1, Dispersed thread 135, 146, 59, 1, 73, 60. 167, c, r, Disperse Violet 4, 13, 36, 56, 31, C, 1, Solvent Violet 13, C, 1, Solvent Black 3, c, r, Solvent Green 3, C, 1, Solvent Yellow 56, 14, 16, 29, C, 1, Solvent Blue 0. Same 35, Same 63, Same 3
6, 50, 49, 111, 105, 97, 11, C, 1, Solvent Red 135, 81, 18, 25, 19, 23, 24, 143, 146,
Binders for the 182° thermal transfer layer include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, Ml cellulose, and cellulose acetate butyrate, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, polyester, and polyacetic acid. Vinyl resins such as vinyl and polyacrylamide can be used.

As an example of a more preferable binder, instead of the above-mentioned ordinary vinyl butyral resin, a binder having a molecular weight of 60.000 to 60.000 is used.
200,000, the weight G% of the vinyl alcohol moiety in the polyvinyl butyral resin is 10 to 40%, preferably 15
~30% and a glass transition temperature of 60°C to 110°C, preferably 70°C to 110°C. If the glass transition point is less than 60°C, the dye may aggregate or precipitate over time;
If the temperature exceeds .degree. C., sublimation of the dye will not occur sufficiently, which is not preferable. If the molecular weight is less than 60,000, the cohesive force as a binder is insufficient, and if it exceeds 200,000, the viscosity during coating becomes too high, causing problems in coating.

If the vinyl alcohol content is less than 10%, the stability of the thermal transfer layer over time will be insufficient, so that aggregation, precipitation, and bleeding of the dye onto the surface cannot be avoided. On the contrary, 40%
If it exceeds this amount, the affinity of the polyvinyl alcohol moiety for the dye prevents sublimation of the dye, resulting in a decrease in printing density.

Regarding the weight of the dye and binder in the thermal transfer layer, it is desirable that the dye/binder ratio is 0.3 or more, and if it is less than 0.3, the printing density and thermal sensitivity will be insufficient. Furthermore, if the ratio of dye/binder exceeds 2.3, the retention of the dye in the binder becomes insufficient and the storage stability of the thermal transfer sheet deteriorates. Therefore, the dye/binder ratio is preferably 0.3 to 2.3, more preferably 0.55 to 1.5.

Preferably, the dye is dissolved in the binder of the thermal transfer layer. In conventional sublimation transfer paper for textiles, the dye is dispersed in a binder, so in order to sublimate the dye, energy is provided to overcome the interactions between the dye molecules and the interactions between the dye molecules and the binder. This necessarily requires high energy, resulting in reduced thermal sensitivity. In this respect, it is advantageous in terms of heat sensitivity if the dye is dissolved in the binder.

For the thermal transfer layer, a dye is selected so that the desired hue can be transferred after printing, and if necessary, two or more thermal transfer layers containing different dyes may be arranged side by side on one thermal transfer sheet. For example, when printing each color repeatedly according to the color separation signal to form an image such as a natural color photograph, it is desirable that the hues of the print are cyan, magenta, and yellow. Three thermal transfer layers containing dyes that give . Alternatively, a thermal transfer layer containing a dye that provides a black hue in addition to cyan, magenta, and yellow may be added. Note that it is preferable to provide a position detection mark at the same time as forming any of the thermal transfer layers, since this eliminates the need for ink or printing process separate from the formation of the thermal transfer layer.

Heat resistant layer It is preferable to provide a heat resistant slip layer 4 separately from the heat resistant slip layer 4 in order to improve the heat resistance of the thermal transfer sheet.

Synthetic ri4 that hardens by heating and forms the heat-resistant layer
Other combinations of Wi and its curing agent can be used. Typical examples are polyvinyl butyral and polyvalent isocyanates, acrylic polyols and polyvalent isocyanates, cellulose acetate and titanium chelating agents, and polyesters and organic titanium compounds. The following table shows the product names and formulations (by weight) of products that are easily available on the market, including these.

No. Synthetic resin that can be cured by heating
Blend m1 Polyvinyl butyral
100 parts “Eslec BX-IJ (Building Chemical) 2 Urethane Polyol
100rDF30-55J (Dainippon Ink) 3
10 for urethane polyol rDF30-554
0Go 1% addition 4 Acrylic polyol [Acrylic A-100
801-PJ (Dainippon Ink) 5 Polyester 1
00 [Byron 200J (Toyobo) 6 〃 “〃” (〃) 1
007 〃 “〃” (〃)
1008 〃 “ ” (〃 )
1009 Cellulose acetate
100rL20J (Vercules)
1001o 〃 “ ”
(〃 ) 10011 Nitrocellulose
20~50 “Nidocero 8374
” (Daicel) 12 Chlorinated rubber
100rcR10J (Asahi Denka) 13 〃 “ ” (〃 )
10014 Melamine “Melan 45” (Hitachi Chemical>
100 hardening agent
Blend amount diisocyanate
Part 45 “Takenate DIIONJ
(Narita Pharmaceutical) Polyisocyanate
20 “Parnock D-750J (Dainippon Ink)” “〃” (〃) 20 II “ll” (ll) 20 11 “〃” (II) 20 Titanium chelating agent 5
~10 “Titabond 50” (Japanese Four Speed) Organic titanium compound
10rA-10J (Japanese 4-speed) rB-104 (lI)
10 titanium chelating agent
5 “TITABOND 5D” (〃 ) Polyisocyanate
10 “Parnock D-750J (Dainippon Ink)”
"〃" (〃) 50~20
! ! "lI" (〃) 30 Organic titanium compound rB-10410 Para-toluene sulfonic acid 20 It may be preferable to add an extender pigment 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.

Formulations are usually suitable at 5-40% resin on a heavy ffi basis. For addition and mixing, it is preferable to use 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 an appropriate brimer.

By the way, generally, the component that imparts lubricity (slip) to the sheet surface and the component that imparts heat resistance tend to cancel each other out. For example, in the heat-resistant slip layer 4, increasing the slipping component reduces the heat resistance. 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 to provide the heat-resistant layer 3 and the heat-resistant slip layer 4 in a laminated manner.By adopting such a structure, (a) both lubricity and heat resistance can be achieved at the same time. (b) The film thickness can be reduced as a result.

Heat-resistant slip layer The heat-resistant slip layer 4 imparts appropriate lubricity (sliding) to the sheet surface and prevents thermal adhesion (sticking phenomenon) between the thermal head and the thermal transfer sheet, thereby improving sheet runnability. It is extremely important to

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

Polyvinyl butyral reacts with isocyanates to form a resin with good heat resistance. The polyvinyl butyral preferably has a molecular weight as high as possible and contains a large amount of -OHI, which is a reaction site with isocyanates. Particularly preferred among polyvinyl butyrals are those having a molecular weight of 60,000 to 200,000, a glass transition temperature of 60 to 110° C., and a vinyl alcohol moiety content of 15 to 40%.

Examples of the isocyanes used in forming the heat-resistant slip layer include polyisocyanates such as diisocyanates and triisocyanates, which may be used alone or in combination. Specifically, the following compounds are exemplified. Paraphenylene diisocyanate, 1-chloro-2,4-phenyl diisocyanate, 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''-1-limethyl-3,3',2'-triisocyanate-2
, 4,6-triphenyl cyanurate.

Isocyanates are generally used in an amount of 1 to 100% by weight, preferably 5 to 60% by weight, based on polyvinyl butyral.

The alkali metal salt or alkaline earth metal salt of phosphoric acid ester has the function of imparting lubricity to the heat-resistant slip layer, and Gafac RD720 manufactured by Toho Kagakuten Co., Ltd. is used. The alkali metal salt or alkaline earth metal salt of this phosphoric acid ester is 1 to 50% based on polyvinyl butyral.
It is used in an amount of 1ffi%, preferably 10 to 40% by weight. Alkali metal salts or alkaline earth metal salts of phosphate esters are added as lubricants in a molecular state dissolved in the binder, so compared to cases where solid lubricants such as mica or talc are added. This has the advantage that roughness does not occur in the printed area.

As the alkali metal salt or alkaline earth metal salt of phosphoric acid ester, sodium salt of phosphoric acid ester is particularly preferable, and examples thereof include the following general formula % (wherein R is alkyl having 8 to 30 carbon atoms) or alkylphenyl group, where n is the average number of added moles of ethylene oxide.) Alkali metal or alkaline earth metal salts of phosphoric acid esters have a , when the former is dissolved in water, D l-15
~7, and the latter has a pI of less than -12.5, which indicates that the acidity is weaker than that of the corresponding phosphoric acid ester. By the way, as mentioned in the previous article, polyvinyl butyral and isocyanates react to form the base of the heat-resistant slip layer, but this reaction is difficult to proceed in a strongly acidic region, takes time, and the degree of crosslinking itself It also becomes lower. Therefore, when a phosphoric acid ester (not in salt form) is added to a reaction system between polyvinyl butyral and isocyanates, the reaction between the two takes an extremely long time, and the degree of crosslinking of the resulting reactant is It has to be low.

On the other hand, when an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester is added to the reaction between polyvinyl butyral and isocyanates, the reaction between the two proceeds quickly and the degree of crosslinking is also large. is obtained. For this reason, a thermal transfer sheet having a heat-resistant slip layer obtained by adding an alkali gold fil or an alkaline earth metal salt of a phosphoric acid ester to a reaction system of polyvinyl butyler J- and isocyanates cannot be stored by winding it up. However, it is considered that the dye in the thermal transfer layer does not migrate into the heat-resistant slip layer.

Furthermore, if an alkali metal salt or an alkaline earth metal salt of a phosphate ester is used as a lubricating agent in the heat-resistant slip layer, even if the heat transfer layer and the heat-resistant slip layer are in close contact with each other, the alkali metal salt or alkaline earth metal salt of a phosphate ester or Another advantage is 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.

Fillers include inorganic materials such as clay, talc, zeolite, aluminosilicate, calcium carbonate, Teflon powder, zinc oxide, titanium oxide, magnesium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde, or organic materials that improve heat resistance. Fillers may be used.

The average particle size of this filler is 3 μm or less, preferably 0.1
It is desirable that the thickness is 2 μm. The filler is used in an amount of 0.1 to 25% by weight, preferably 1.0 to 10% by weight, based on the polyvinyl butyral.

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 completely eliminated.

To provide the heat-resistant slip layer on the base sheet 1, the above components are dissolved in an appropriate solvent to form an ink for forming the heat-resistant slip layer, and this is formed on the base sheet 2 by an appropriate printing method or coating method. Then, by heating to a humidity of 30 to 80° C., the polyvinyl butyral and isocyanates are reacted while drying to form a heat-resistant protective film.

At this time, it is preferable to prepare the filler crosstalk fraction composition by kneading the filler in advance with an alkali metal salt or alkaline earth metal salt of a phosphoric acid ester.

The heat-resistant slip layer has a thickness of 0.5 to 5 μm, preferably 1 to 5 μm.
It is preferable to have a film thickness of 2 μm.

If this film thickness is thinner than 0.5 μm, it will not be effective as a heat-resistant slip layer, and if it is thicker than 5 μm, the heat transfer from the thermal head to the sublimation transfer layer will be poor, resulting in low print density. A drawback arises.

As mentioned above, by forming the heat-resistant slip layer from (a) a reaction product of polyvinyl butyral and isocyanates, (b) an alkali metal salt or alkaline earth metal salt of a phosphoric acid ester, and (c) a filler. However, in some cases, when a thermal transfer sheet having such a heat-resistant slip layer is transferred inside a printing transfer device, for example, tension or thermal stress applied to the thermal transfer sheet may be generated. Depending on the printing pressure of the head, problems may arise in the transportability of the thermal transfer sheet.

In such a case, the above (a) should be added to the heat-resistant slip layer.
In addition to the components (b) and (c), it is preferable to add (d) a phosphoric acid ester that is not in a salt form. As the phosphoric acid ester that is not in the salt form, those that are not in the salt form of the phosphoric acid ester shown in the above-mentioned alkali metal salts or alkaline earth metal salts are used. Blysurf A208S manufactured by Pharmaceutical Co., Ltd., GAFACR8710 manufactured by Toho Chemical Co., Ltd., and the like may be used.

Such phosphoric acid esters not in salt form are used in an amount of 1 to 501 ffi%, preferably 1 to 30 ffi%, based on polyvinyl butyral.

If it exceeds 50% by weight, it is not preferable because the dye or pigment in the thermal transfer layer, particularly in the heat-resistant slip layer, migrates when stored in a stacked or wound state.

The heat-resistant slip layer is mainly composed of the above-mentioned components, but a small amount of granular material such as talc, silica, charcoal, or Teflon powder may be added to prevent blocking in the rolled state.

The order in which the thermal transfer layer 2, heat-resistant &3, and heat-resistant slip layer 4 are provided on the base sheet 1 is preferably heated to promote the reaction between polyvinyl butyral and isocyanate, and during this heating, the thermal transfer layer is not affected by heat. In order to prevent this from occurring, it is preferable to provide the heat-resistant slip layer 4 on the base sheet 2 and then provide the thermal transfer layer 2.

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

(a) Even if the product is heated to a much higher temperature than the thermal head, no sticking phenomenon occurs.

(b) No roughness occurs in the printed area.

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

(d) When the thermal transfer sheet is transferred by a printing transfer device or the like, the thermal transfer sheet does not stick to the roll or the like, and therefore the transfer performance is excellent.

[Embodiments of the invention]

Example 1 A heat-resistant layer ink composition (2) having the composition shown below (mold assembly part) was prepared, and a 9μ thick polyethylene terephthalate film "'5-PETJ" was used as a base film.
(Oriental!!J) was coated with Myaba #8 and then mHA was dried.

(Ink composition for heat-resistant layer ■) Polyvinyl butyral resin [Eslec Bx-1] (manufactured by 8!i Mizu Kagaku) 4.5 parts Toluene 45 parts Methyl ethyl ketone 45.5 parts Diisocyanate "Takenate D-11ONJ (manufactured by Shikinichi Yakuhin) 75% ethyl acetate solution 2.0 parts Next, an ink composition I for a heat-resistant slip layer having the following composition was prepared, and on top of the above-mentioned ink composition I for a heat-resistant layer, coated with Myabar #6, Dry with warm air.

(Ink composition for heat-resistant slip layer I) Polyvinyl butyral resin "S-LEC BX-IJ 5.7 Toluene 43.1 Methyl ethyl ketone 43.1 phosphate ester" Blysurf A-208SJ (Dai-Kogyo Seiyaku Co., Ltd.) 1.3 phosphoric acid Ester sodium jn 1.7rGAFA CRD7
20J (manufactured by Toho Chemical) 1.7 Talc [Micro Ace L-1J (manufactured by Nippon Taruri) 1.2 Amine catalyst [DesmoRapid PPJ (manufactured by Sumitomo Bayer Urethane) 0.1 Diisocyanate "coronated 45% ethyl acetate solution" (manufactured by Nippon Polyurethane) 3.8 This film was further heated in an oven at 60° C. for 12 hours to undergo a curing treatment. The ink application m after drying was approximately 1.2 g/ffl.

Separately, an ink composition for forming a thermal sublimation transfer layer having the following composition was prepared, and coated on the surface of the base film opposite to the heat-resistant layer with Myabah #10, and dried with warm air. The coating weight of this transfer layer was approximately 1.2 g/bottom.

(Thermal sublimation transfer layer forming ink) Disperse dye (Nippon Kayaku Kayaset Blue 14) 4-type can part polyvinyl butyral (Sekisui Chemical S-LEC BX-1) 4.3 parts toluene 40 parts methyl ethyl ketone 40 fflffi Part Isobutanol 10 Mold assembly part On the other hand, synthetic paper rYUPo-FP with a thickness of 150μ was used as the base film.
Using G150J (manufactured by Tamago Yuka Co., Ltd.), an ink for forming an image receiving plate having the following composition was applied with a wire bar #36 so that the dry coating amount was 4.0 g/rd to prepare a thermal transfer sheet.

(Ink for forming image-receiving layer) Polyester resin [Vylon 200J (Oriental!!1) 5 mm
Polyester resin "Vylon 290J (manufactured by Toyobo) 5 1 parts Amino-modified silicone oil (manufactured by Shin-Etsu Chemical) 0.5 parts Epoxy-modified silicone oil (manufactured by Shin-Etsu Chemical) 0.5ff! Part toluene 44.5 mm 44.5 parts methyl ethyl ketone 44.5 parts As described above, stack the heated heat sublimation transfer sheet and the heat transfer sheet so that the heat transfer layer and the receptor layer are in contact with each other, and perform recording from the heat-resistant layer side using a thermal head. Recording conditions were: 1 W/dot of chemical pressure, pulse width: 0.3 to 4.5.
m5ec, dot density=3 dots/ms.

No sticking occurred at all, no wrinkles occurred, and the thermal transfer sheet ran smoothly.

When printing 211 degrees was measured with a Macbeth densitometer RD-9184, the reflection density of the high-density colored part with a pulse width of 4.5 m5ec was 1.70, and the pulse width was 0.3m5.
The ec part was 0.16, and a record with gradation depending on the applied energy was obtained.

I tried printing under the same conditions as above.

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

(Ink composition for heat-resistant layer ■) Acrylic polyol "Acrit 6416MA 45% solution J 41.2 parts by weight ffi (manufactured by Taisei Kako) Toluene 26.3 parts by weight Methyl ethyl ketone 26.3 parts by weight diisocyanate "Coronate 145% acetate ester solution" 6. 2 parts by weight (Japan Polyurethane product) Next, in the same manner as in Example 1, ink composition I for heat-resistant slip layers was applied on the heat-resistant layer and cured by heating, and then a heat-sensitive sublimation transfer layer was applied in the same manner. Again, it was overlapped with the thermal transfer sheet used in Example 1 and printed under the same conditions.

In this case as well, no sticking phenomenon or wrinkles were observed, and good printing was achieved with no roughness even in solid areas.

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 talc in Heat-resistant Slip Ink Composition I was replaced with calcium carbonate, and printing was performed under the same conditions.

(Ink composition for heat-resistant slip layer ■) Polyvinyl butyral resin [S-LEC BX-IJ 5.7 parts by weight Toluene 43.1 parts by weight Mebru ethyl ketone 43.1 fffffi parts Phosphoric ester [Blysurf A-208SJ 1.3 Parts by weight (parts by weight)
(manufactured by Kogyo Seiyaku) Phosphate ester sodium salt rGAFACRD720J 1.7 parts by weight (Toyo Kagaku'!l) Calcium carbonate [Shiraenka 004 1.2 type assembly part (made by Shiraishi Calcium) Amine catalyst [Desmorapirad PPJ 0.11 hanging part ( (manufactured by Sumitomo Bayer Urethane) Diisocyanate "Coronate L 45% ethyl acetate solution" 3.8 heavy foot part (manufactured by Nippon Polynyrethane) In this case as well, no sticking phenomenon or wrinkles were required, and good printing was achieved.

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

In this case as well, no sticking phenomenon or wrinkles were observed, and good printing was achieved.

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

(Ink composition for heat-resistant layer ■) Acrylic polyol [Acrit 6416MA 45% solution J 41.2 parts (manufactured by Taisei Kako) Toluene 23.5 parts by weight Methyl ethyl ketone 25. Off1M part diisocyanate "Coronate 145% acetate ester solution" 7.5 parts (manufactured by Nippon Polyurethane) Calcium carbonate (white 2'l! No wrinkles were observed and good printing was achieved.

Circle/[16 Aminosilicate, clay, talc, zeolite, Teflon powder, zinc oxide, magnesium oxide, titanium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde instead of calcium carbonate as fillers for heat-resistant layer ink. , otherwise the same as in Example 5.
A thermal transfer sheet was prepared in the same manner as above, and printing was performed under the same conditions. In this case as well, no sticking phenomenon or wrinkles were observed, and good printing was achieved.

[Brief explanation of drawings]

The accompanying drawing is a cross-sectional view of a thermal transfer sheet according to the present invention. DESCRIPTION OF SYMBOLS 1... Base sheet, 2... Thermal transfer layer, 3... Heat-resistant layer, 4... Heat-resistant slip layer.

Claims (1)

[Scope of Claims] 1. The base sheet has a thermal transfer layer on one side, and on the other side, (1) a heat-resistant layer formed by curing a synthetic resin that can be cured by heating with a curing agent; (2) (a) Reaction product of polyvinyl butyral and isocyanates, (b)
A thermal transfer sheet comprising an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester and (c) a heat-resistant slip layer comprising a filler, which are laminated in this order. 2. The synthetic resin and curing agent that can be cured by heating, which constitute the heat-resistant layer, are (a) polyvinyl butyral and polyvalent isocyanate, (b) acrylic polyol and polyvalent isocyanate, and (c) cellulose acetate and a titanium chelating agent. , and (ii) a combination of polyester and an organic titanium compound. 3. A patent that uses a granular material selected from the group consisting of calcium carbonate, talcum 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. 4. The filler used in the heat-resistant slip layer is calcium carbonate,
The thermal transfer sheet according to claim 1, which is selected from the group consisting of talc, aluminosilicate, clay, zeolite, Teflon powder, zinc oxide, magnesium oxide, titanium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde. 5. The thermal transfer sheet according to claim 1, wherein the thermal transfer layer is a thermal sublimation transfer layer comprising a thermally transferable dye and a binder resin. 6. The thermal transfer sheet according to claim 1, wherein the thermal transfer layer is a heat-melting transfer layer comprising a dye or pigment and wax.