JPH0220389A - Heat-sensitive transfer material - Google Patents

Abstract

PURPOSE:To ensure that no blank exists even in a material to be recorded with low surface smoothness and a transfer-recorded image with high density is obtained and make possible the lift-off deletion of the image by providing at least first to fourth ink layer sequentially from the support side, making the support and the fourth ink layer with specific thicknesses and allowing at least the third ink layer to contain a coloring agent. CONSTITUTION:A heat-sensitive transfer material 1 consists of first to fourth ink layer 3-6 sequentially laminated from a support, on this support. The third ink layer 5 contains a coloring agent, and the thickness of the support is min. 7mum and max. 12mum, while the thickness of the fourth ink layer 6 is min. 4mum and max. 9mum. A transfer-recorded image with high density without any blank can be obtained even on a material to be recorded with low surface smoothness by specifying the thicknesses of the support 2 and the ink layer 6 as described above. For the deletion of an image, the transfer-recorded image 11 is brought to come in contact with the ink layer 6, and a heat energy is applied to the ink layer 6. Then the ink layer 6 adheres to the transfer-recorded image 11 and at that time, a release member 10 is allowed to protrude and thereby the transfer-recorded image 11 is delected due to a lift-off action with the use of a heat-sensitive transfer material 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a thermal transfer material used for thermal transfer recording, and is suitable for recording media with high surface smoothness as well as recording media with low surface smoothness. The present invention relates to a thermal transfer material capable of producing a recorded image that has good print quality and can be erased by lift-off.

[Conventional technology]

Thermal transfer recording has the general characteristics of thermal recording such that the equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability. In addition, it does not require colored processed paper, and the recorded image is durable. It has been widely used recently because of its excellent properties. However, even in such a thermal transfer recording method, there are still some points to be improved.

The first point is that the quality of transferred recorded images on recording materials such as paper with poor surface smoothness is poor.

The second point is that the transferred recorded image obtained by the thermal transfer recording method cannot be easily erased even if it is due to printing error.

As a general means of erasing erroneous records, there is the use of concealing paints that have become widely used in recent years, and thermal transfer recording methods also contain concealing coloring materials that are almost the same color as the recording material. A method has already been proposed in which a heat-sensitive transfer material having a heat-transferable ink layer is used to cover erroneously recorded areas with the transfer ink layer. However, in the method of coating with a transfer ink layer, the color of the recording medium and the opaque coloring material are not completely the same, and the erased area is raised by coating with the ink layer, making it easier to distinguish the erased area, which is preferable in terms of appearance. It's not a thing. Furthermore, as another erasing means, a method has been proposed in which an erroneously recorded image formed on a recording medium is adhesively peeled off using a heat-sensitive adhesive tape, that is, a lift-off erasing method.

However, these erasing methods require both a thermal transfer material to form a transferred recorded image on the recording medium and an erasing sheet to erase the transferred recorded image, and a thermal transfer printer requires a tape for printing and erasing. This requires a switching mechanism, which has the disadvantage that the structure of the printer device becomes complicated and large.

As a method for improving the above-mentioned drawbacks, a (self-collectible) thermal transfer material has been proposed in which lift-off erasure can also be performed using the thermal transfer material that transfers a recorded image onto a recording paper. JP-A-58-74368 discloses a heat-sensitive laminate in which both recording and erasing can be performed by means of an active layer on a resistive support. That is, this active layer is constructed so that it develops adhesive force when heated to a temperature lower than the heating temperature during recording, so that the transferred recorded image can be erased by peeling it off. Also,
JP-A No. 61-23992 proposes a thermal transfer material consisting of a coloring agent, a binder agent, and a thermal adhesive material having a higher softening point than the binder agent on a support, and uses a thermal head as a heat source. It has been disclosed that recording is performed using low thermal energy using a recording medium, and that erroneously recorded images are peeled off and erased by applying higher thermal energy than during recording.

[Problem that the invention seeks to solve]

However, a heat-sensitive transfer material that can provide a transferred recorded image of good recording quality even on a recording medium with low surface smoothness and also has a satisfactory self-collection effect has not been obtained, and the development of such a material is desired. According to conventional self-collecting thermal transfer materials, especially in recording materials with low smoothness, the convex portions of the recording medium penetrate through the transferred ink layer, resulting in "white spots" where the convex portions are dotted in the recorded image. In many cases, the recorded image that has entered the concave portion of the recording medium cannot be peeled off, resulting in incomplete erasure.

Further, Japanese Patent Application Laid-Open No. 156993/1983 discloses a self-collecting thermal transfer material having an ink layer on a support via a separation layer having a relatively low melt viscosity.

The material used for this separation layer must not change in quality during storage, etc., and must have a low melt viscosity.
Generally, they tend to be hard and brittle, and when lift-off erasing is performed, defects such as the entire ink layer peeling off from the support are likely to occur. Therefore, the latitude of usage conditions such as applied energy is narrow, and erasing tends to be incomplete. In order to solve this problem, it is necessary to use a component with relatively high viscosity in the separation layer, which in turn requires a large force to separate from the support during recording. For bodies, recorded images tend to have many defects.

Therefore, the present applicant has proposed a thermal transfer material that has an ink layer of at least three layers, has a high printing density even on recording materials with low surface smoothness, and can further erase the transferred recorded image by lift-off. (Patent application 1986-29904
No. 6).

The present invention is an improvement based on the heat-sensitive transfer material of the above-mentioned Japanese Patent Application No. 62-299046. It is an object of the present invention to provide a heat-sensitive transfer material on which a transferred recorded image with very high density without white spots can be obtained, and which can be erased even better by lift-off.

[Means for solving problems]

The thermal transfer material of the present invention has at least a first ink layer, a second ink layer, a third ink layer, and a fourth ink layer in order from the support side on a support, and the thickness of the support is The thickness of the fourth ink layer is 4 μm or more and 9 μm or less, and the third ink layer contains a colorant. .

Hereinafter, an example of the present invention will be described in detail with reference to the drawings as necessary. In the following descriptions, "%" is used to express quantitative ratio.
” and “parts” are based on weight unless otherwise specified.

As shown in FIG. 1, the thermal transfer material 1 of the present invention has at least four ink layers, and a first ink layer 3. The second ink layer 4 is formed by sequentially laminating a third ink layer 5 and a fourth ink layer 6. The first ink layer 3 is firmly adhered to the support 2 without being separated either at the interface with the support 2 or inside thereof even during recording by heating.

During recording by heating, the second ink layer 4 is separated at the interface with the first ink layer 3 or inside the ink layer 4, and the third ink layer 5 and fourth ink layer 6 are applied to the recording medium. It is easy to transfer (but the second ink layer 4
The non-heated portion firmly adheres to the first ink layer 3 and the third ink 5, and prevents the ink layer 5 from being transferred to the recording medium. A transferred recorded image of the heated pattern is formed by the contrast between the heated portion and the non-heated portion.

The third ink layer 5 contains a colorant and has the function of coloring the transferred recorded image.

The fourth ink layer 6 is a layer that is transferred to form a bridge between the convex portions on the surface of the recording medium, and has a certain degree of film strength after heat is applied. The third ink layer 5 also
Like the fourth ink layer 6, it has a certain degree of film strength after heat application.

Generally, a plastic film is preferably used as the support 2, and has good heat resistance, tensile strength, and elongation.

In order to satisfy various properties such as tear strength, plastic films are subjected to uniaxial or biaxial stretching treatment, so the molecular chains of the film are oriented in a certain direction. As a result, although the above-mentioned properties improve and reach a satisfactory level, other properties may deteriorate. For example, there is a decrease in surface adhesion. For example, polyester film has poor adhesion, and the second ink layer 4
When an ink layer is formed on a polyester film using a component mainly consisting of a material with sharp melt properties and low melt viscosity, defects such as ink peeling are extremely likely to occur.

By forming an ink layer by coating like the first ink layer 3 on the plastic film, the molecular chains in the coating film exist randomly, so the second ink layer 4
The adhesion between the ink and the support 2, such as a plastic film, is improved, and defects such as ink peeling can be avoided.

The first ink layer 3 does not completely melt even if it is softened by heating, does not reduce its adhesion to the support 1, and does not substantially transfer to the recording medium side, that is, has substantially non-transfer properties. Although it is preferable that the ink layer is completely melted, there is no problem even if it is completely melted as long as it does not prevent the ink from being divided by the second ink layer 4 during recording. The viscosity when melted, especially the viscosity at 150°C, is 5,0OOcps or more, preferably 10,0OOcps.
It is sufficient if it is at least cps.

Furthermore, the first ink layer 3 has a certain degree of flexibility so that when the fourth ink layer 6 peels off and erases the erroneously recorded image, it follows the irregularities of the erroneously recorded image and comes into sufficient contact with it. ing.

For this reason, the first ink layer 3 is configured to contain a thermoplastic resin so that it has a high cohesive force when heated and also has a high adhesion force to the support. The thermoplastic resin contained in the first ink layer 3 has a glass transition temperature of -40°C to 30°C.
, and more preferably -30°C to 15°C. When the thermoplastic resin is a mixture of multiple types of thermoplastic resins, and the glass transition temperature TgM of such a mixture of thermoplastic resins is defined as, TgM is also preferably within the above temperature range. In other words, even if the thermoplastic resin is a mixture of multiple types of resin, if the glass transition temperature of the mixture is defined as in the above formula (A), the mixture of thermoplastic resins can be composed of a single resin. It can be thought of as a thermoplastic resin. In the above formula (A), T gn is the glass transition temperature of one thermoplastic resin constituting the thermoplastic resin mixture, W is the total weight of the thermoplastic resin mixture, and wn is the thermoplastic resin mixture. The weight of one thermoplastic resin. If the glass transition temperature of the thermoplastic resin is too high, flexibility will be lost and adhesion to the support will be reduced. Furthermore, if the glass transition temperature is too low, the adhesive will become excessively sticky, which will cause problems in handling during production.

Furthermore, in order to increase the cohesive force of the first ink layer 3, the first
The weight average molecular weight of the thermoplastic resin contained in the ink layer 3 is preferably 10,000 or more, more preferably 50,000 or more. Note that the weight average molecular weight here refers to a value measured by GPC (gel permeation chromatography). Furthermore, when the thermoplastic resin is a mixture of a plurality of resins, the weight average molecular weight refers to the weight average molecular weight of the mixture as a whole.

Examples of the thermoplastic resin used for the first ink layer 3 include polyvinyl acetate resin such as vinyl acetate-ethylene copolymer, epoxy resin, polyurethane resin, acrylic resin, polyester resin, styrene-butadiene rubber, Elastomers such as isoprene rubber can be used. In addition, petroleum resins, phenolic resins,
Melamine resins, urea resins, and polystyrene resins may be appropriately mixed and used. Further, fillers such as titanium oxide, clay, zinc white, alumina hydrate, etc., plasticizers, stabilizers, etc. can be mixed with the above materials as appropriate.

The first ink layer 3 can be obtained by appropriately adjusting the molecular weight and crystallinity of the above-mentioned materials, or by mixing a plurality of materials.

The content of thermoplastic resin in the first ink layer 3 is 70
% or more and 100% or less, more preferably 90% or more and 100% or less.

The thickness of the first ink layer 3 is preferably 0.5 μm or more, considering the ability to follow a recording medium with low surface smoothness.
Considering heat conduction, the thickness is preferably 5 μm or less.

The second ink layer 4 is preferably one that undergoes sharp melting when heated or whose adhesive strength decreases at the interface with the first ink layer 3 or the third ink layer 5. 1st
Ink layer 3. Third ink layer 5 and fourth ink layer 6
has a high cohesive force when heated and also contains a relatively large amount of thermoplastic resin. Therefore, the second ink layer 4 has a melting point of 5 due to the requirement of sharp melting properties or a reduction in adhesive strength at the interface.
0℃ or higher, and the melt viscosity at 150℃ is 500c
It is preferable that it is below ps. As the material constituting the second ink layer 4, the following materials are preferred, and waxes are particularly preferred.

The above-mentioned waxes include natural waxes such as carnauba wax, candelilla wax, rice wax, vegetable waxes such as Japanese wax, mineral waxes such as ceresin wax and montan wax, and derivatives thereof.
For example, examples of derivatives of montan wax include acid wax, ester wax, and partially saponified ester wax. Also, paraffin wax is a petroleum wax.

Microcrystalline wax, etc. As the synthetic wax, polyethylene wax, especially low molecular weight oxidized polyethylene, Fischer-Tropsch wax, etc. can be used. The above-mentioned waxes are contained in the second ink layer 4 in an amount of 80% or more, preferably 90% or more, and are prepared alone or in combination so as to satisfy the above-mentioned melting point and melt viscosity.

The melt viscosity of the second ink layer 4 is preferably 200 cps or less, particularly 100 cps or less at 150°C. Carnauba wax and paraffin wax are extremely suitable under the above conditions and sharp melt properties. Said carnauba wax.

The above-mentioned characteristics can be fully satisfied even when the second ink layer 4 contains paraffin wax in an amount of 40% or more, even 50% or more, based on the total wax contained in the second ink layer 4.

The thickness of the second ink layer 4 is preferably 0.5 to 5 μm.

The melt viscosity referred to in the present invention is measured using a Rotovisco RV12 type rotational viscometer manufactured by Haake, West Germany.

Also, coloring agents are added to the waxes mentioned above, if necessary.

Fillers such as titanium oxide, clay, zinc, and alumina hydrate, as well as plasticizers, surfactants, and stabilizers are appropriately mixed and the second
The ink layer 4 can also be made as follows.

The third ink layer 5 has a coloring function, film strength immediately after heat application,
It functions to influence the subsequent change in membrane strength over time, and the fourth
The ink layer 6 has the function of adhesion to the paper in the heat application section and, like the third ink layer 5, the function of controlling the film strength immediately after heat application and the change in film strength over time.

Since the third ink layer 5 has a coloring function, it contains a colorant. Specifically, the colorant used is as follows:
For example, carbon black, nigrosine dye, lamp black, Sudan black SM, first yellow G, benzidine yellow, pigment yellow, India first orange, irgazine red, varanitroaniline red, toluidine red, carmine FB, Permanent Bordeaux FRR, Pigment Orange R,
Lysol Red 2G, Lake Red C, Rhodamine FB.

Rhodamine B Lake, Methyl Violet B Lake,
Phthalocyanine Blue Pigment Blue Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, Zapon Fast Yellow CGG, Kayaset Y963. Kayaset YG, Sumiplast Yellow GG
, Zapon First Orange RR, Oil Scarlet, Sumiplast Orange G, Orazole Brown G, Pomelo First Scarlet CG, Eisenspiron Red BEH, Oil Pink OP, Victoria Blue F4R.

One or two of known dyes and pigments such as Firstken Blue 500F, Sudan Blue, Oil Peacock Blue, etc.
More than one species can be used.

The content of the colorant contained in the third ink layer 5 is 3 to 90
%, more preferably 10 to 80%.

Furthermore, if necessary, in addition to the coloring agent, fine metal powder, inorganic powder,
A filler made of metal oxide or the like may be added as appropriate.

The third ink layer 5 contains a heat-fusible material together with the colorant in order to function to control film strength.

The thermofusible materials contained in the third ink layer 5 include polyolefin resins, polyamide resins, polyester resins, and epoxy resins.

Polyurethane resins, polyacrylic resins, polyvinyl chloride resins, cellulose resins, polyvinyl alcohol resins, oil-based resins, phenolic resins, polystyrene resins, vinyl acetate resins.

natural rubber, styrene butadiene rubber, imprene rubber,
Elastomers such as chloroprene rubber.

Whale wax containing 70% or more of polyisobutylene, polybutene, etc., and other substances other than resin in some cases.

Natural waxes such as beeswax, lanolin, carnauba wax, candelilla wax, montan wax, ceresin wax, petroleum waxes such as paraffin wax, microcrystalline wax, oxidized waxes, and ester waxes.

Synthetic waxes such as Fischer-Tropsch wax and polyethylene wax, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and stearyl alcohol.

It is preferable to use a suitable mixture of higher alcohols such as behenyl alcohol, esters such as fatty acid esters of sucrose and fatty acid esters of sorbitan, amides such as oleylamide, plasticizers, and oils such as mineral oil and vegetable oil. The thickness of the third ink layer 5 is 0.5 to 5 μm
A range of is preferred.

The fourth ink layer 6 has the function of providing a clear transferred image even on a recording medium with low smoothness and is lift-off erasable, and is formed mainly of a heat-melting material and In addition to the meltable material, it is composed of a colorant 9, a dispersant, a plasticizer, an oil agent, a filler, etc. as necessary.

By using a thermoplastic resin as the heat-melting material, the ink layer can be transferred to a non-recording medium with low smoothness so as to bridge the convex portions on the surface of the recording medium. A transferred recorded image with no transfer defects or deformed characters and excellent scratch resistance can be obtained. The content of the thermoplastic resin in the fourth ink layer 6 is preferably 50% or more.

As the thermofusible material contained in the fourth ink layer 6, the resin contained in the third ink layer 5 can be used as is.

Further, as for other components other than the resin that may be added as appropriate, those that can be used in the third ink layer 5 can be applied as they are. Furthermore, it is possible to include a coloring agent in the fourth ink layer 6, but adding too much is not preferable because it will result in unerased residues during off-erasing. For this reason, the fourth
Even if the ink layer 6 contains a colorant, it is preferably 5% or less, more preferably 3% or less.

In order to control the film strength of the third ink layer 5 and the fourth ink layer 6 immediately after heat application, that is, at the time of recording, the composition, cohesive force, molecular weight, etc. of the materials from the above-mentioned material group are changed as appropriate. However, in order to obtain good transferability to a recording medium with low surface smoothness, it is desirable that the cohesive force 2 molecular weight is high. Further, the change in film strength over time after heat application can be controlled by appropriately changing the composition, crystallinity, cohesive force, molecular weight, etc. of the materials from the above-mentioned material group. In particular, it is desirable to use a polymer material with a high degree of crystallinity to take advantage of the recrystallization delay time, such as a polymer material mainly composed of olefins, such as low molecular weight polyethylene oxide.

Ethylene-vinyl acetate copolymer, vinyl acetate-ethylene copolymer, ethylene-acrylic acid copolymer.

Ethylene-methacrylic acid copolymer, ethylene acrylic acid ester copolymer, etc., and polyamide.

Polyester is used as the main component.

As the support 2, conventionally known films can be used as they are, such as polyester.

Plastic films with relatively good heat resistance, such as polycarbonate, triacetyl cellulose, polyamide, and polyimide, can be suitably used.

In addition, when a thermal head is used as a means for applying heat to the thermal transfer material, the surface of the support that comes into contact with the thermal head is
Silicone resin, fluororesin, polyimide resin, epoxy resin, phenolic resin.

By providing a heat-resistant protective layer made of melamine resin, nitrocellulose, etc., the heat resistance of the support can be improved, or it is also possible to use support materials that could not be used conventionally.

In the thermal transfer material of the present invention, the thickness of the support 2 is 7 μm or more and 12 μm or less, and the thickness of the fourth ink layer 6 is 4 μm or more and 9 μm or less. In this way, by regulating the thickness of the support 2 and the fourth ink layer 6, a high-density transferred recorded image without white spots can be obtained even on a recording medium with low surface smoothness, and moreover, it is possible to obtain a high-density transfer recorded image without any white spots, and also to prevent lift-off. No erased residue is generated even after erasing.

If the thickness of the support 2 is too thin, the thermal energy supplied to the ink layer will increase, causing the ink layer to melt excessively. Therefore, the convex portions on the surface of the recording medium are exposed to the third layer containing the colorant.
When the ink layer 5 is penetrated and the ink layer is transferred to the recording medium, the transferred recorded image becomes a state in which the convex portions of the recording medium are interspersed with white areas, resulting in a recorded image with a low density as a whole.

Further, in this case, the third ink layer 5 containing the colorant penetrates deeply into the recesses on the surface of the recording medium, and the third ink layer 5 and the recording medium come into wide contact with each other, causing the colorant to soak into the recording medium. It's gone. As a result, even if an attempt is made to erase the transferred recorded image by lift-off, the colorant in the recesses on the surface of the recording medium or the colorant that has soaked into the recording medium cannot be completely removed, resulting in unerased residue.

On the other hand, if the thickness of the support 2 is too thick, the thermal energy supplied to the ink layer will be small, and the fourth ink layer 6 furthest from the heating means will not have enough thermal energy, and the heated part and the non-heated part will be The difference disappears. As a result, the ink layer cannot be sharply cut at the boundary between the heated portion and the non-heated portion, and whisker-like irregularities occur at the edge portions of the transferred recorded image (that is, the cutability of the transferred recorded image becomes poor).

Furthermore, even if the thickness of the fourth ink layer 6 is too thin, the convex portions on the surface of the recording medium will penetrate through the third ink layer 5, resulting in a transferred recorded image with white areas and a recorded image with low density. Erased residue will be generated. If the fourth ink layer 6 is too thick, as in the case where the support is thick, the thermal energy supplied to the fourth ink layer 6 will be insufficient, resulting in a recorded image with poor sharpness.

The total thickness of the thermal transfer material of the present invention is 13 to 30 μm.
Furthermore, 15-25 micrometers is preferable.

In order to obtain the heat-sensitive transfer material 1 of the present invention, first the above-mentioned heat-melting material and a coloring agent are added as necessary.

The mixture is melted and kneaded with additives using a dispersion device such as an attritor, or kneaded with an appropriate solvent to obtain a coating ink that is hot-meltable or in the form of a solution or dispersion. Next, the coating ink is applied onto the support material 2 using an applicator or a coating bar, and if necessary, it is dried to complete the thermal transfer material 1.

Next, a thermal transfer recording method using the thermal transfer material of the present invention will be explained.

In FIG. 2, the thermal transfer material 1 has a fourth ink layer 6.
It comes into contact with the recording medium 7, and thermal energy is applied in a pattern from the heating element 9 of the thermal recording head 8 from the support 2 side. The first ink layer 3 of the thermal transfer material 1 firmly adheres to the support 2 even when the thermal energy is applied, and is not transferred to the recording medium 7 side. However, the fourth ink layer 6 exhibits adhesive force to the recording medium 7 and is transferred onto the recording medium 7 with appropriate film strength. Further, at this time, the heat applied portion of the second ink layer 4 undergoes sharp melting, becomes semi-liquid or liquid, and the melt viscosity also decreases.
Cohesive failure is very likely to occur.

However, since the non-heat-applied portion of the second ink layer 4 is not melted, it maintains a high cohesive force and maintains strong adhesion between the first ink layer 3 and the third ink layer 5.

Moreover, at this time, the third ink layer 5 and the fourth ink layer 6 are firmly adhered to both the heat applied part and the non-heat applied part, and as a result, the adhesive force between the heat applied part and the non-heat applied part is reduced. The contrast becomes extremely clear, and a transferred image 11 is formed on the recording medium 7.

Next, an erasing method using the heat-sensitive transfer member of the present invention will be explained. In FIG. 3, a transferred recorded image 11 is formed on a recording medium 7 using the thermal transfer material of the present invention. This transferred recorded image 11 and the fourth ink layer 6 of the thermal transfer material 1 are brought into contact with each other, and the heat generating element 9 of the thermal recording head 8 is placed in the same or enlarged area as the transferred recorded image 11 from the support 2 side.
More thermal energy is applied. As a result, the fourth ink layer 6 of the thermal transfer material 1 develops an adhesive force similar to that during recording, and adheres to the transferred recorded image 11 on the recording medium 7. At this time, the cohesive force of the second ink layer 4 of the thermal transfer material 1 decreases, but as shown in FIG. After the strength of the ink layer, that is, the adhesive force between the first ink layer 3 and the third ink layer 5 and the cohesive force of the second ink layer, is restored,
The recording medium and the thermal transfer material 1 are separated.

At this time, the adhesive force between the fourth ink layer 6 and the transferred recorded image 11 also increases, and the transferred recorded image 11 is
Lift-off cancellation of is achieved.

When carrying out lift-off erasing of a recorded image transferred by the heat-sensitive transfer material of the present invention, lift-off erasing may be performed using a heat-sensitive adhesive tape instead of using the heat-sensitive transfer material itself as described above.

As explained above, in the thermal transfer material of the present invention, the thickness of the support is 7 μm or more and 12 μm or less, and the thickness of the fourth ink layer is 4 μm or more and 9 μm or less. Transfer recorded images with uniform density and no white spots can be obtained not only on recording materials with high smoothness but also on recording materials with low smoothness.Furthermore, when the obtained transferred recorded images are lifted off and erased, almost no loss occurs. This makes it possible to modify and erase without leaving any residue.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that the weight ratios shown below are the solid content ratios.

〔Example〕

Vinyl acetate-ethylene copolymer resin with a glass transition temperature of 0°C and a weight average molecular weight of 779,000 (ethylene content: 20%)
An emulsion (non-volatile content: 40%) using an applicator was applied onto each polyethylene terephthalate film having the thickness shown in Table 1, and dried for 1 minute in hot air drying at 80°C. A first ink layer of 0 μm was obtained.

Next, on the first ink layer, an aqueous dispersion of the following formulation 1 was diluted twice, and applied using an applicator at 60°C.
Dry for 1 minute during hot air drying to obtain a thickness of 1.0
A second ink layer of .mu.m was applied. The melting point of this second ink layer is 80°C, and the melt viscosity at 150°C is 20cp.
It was s.

Processing Analysis: The above-mentioned formulation 2 was mixed uniformly using a propeller type stirrer to obtain coating liquid 2. Coating liquid 2 was applied onto the second ink layer using an applicator and dried with hot air at 60° C. for 1 minute to form a third ink layer with a thickness of 1.5 μm.

Coat the ink layer using an applicator so that the thickness after drying becomes the thickness of the fourth ink layer shown in Table 1,
A thermal transfer material of the present invention was obtained.

The 25 types of heat-sensitive transfer materials obtained as described above were cut into 8 mm width, and an electronic typewriter 8P manufactured by Canon Co., Ltd. was used.
400X, and bond paper with low smoothness (Beck smoothness of 2 to 3 seconds) was used as the recording medium to evaluate recording and lift-off erasure. The evaluation results are shown in Table 1.

The typewriter 8P400X has a heater built into the thermal recording head for the purpose of heating the thermal transfer material above room temperature prior to the recording operation, but in this evaluation, the heater was not activated. In addition, lift-off erasure can be evaluated by loading the same thermal transfer material used for printing into the thermal correction tape storage section of the 5P400X.

The above formulation 3 was uniformly mixed in the same manner as formulation 2 to obtain coating liquid 3. Coating liquid 3 is applied to the third table 1 to explain the erase method. Upper row: Printing performance. Lower row: Erasing performance. ◎: Very good. ○: Good.

△: No problem in actual use, ×: Significantly inferior

[Brief explanation of the drawing]

Claims (1)

[Claims] On the support, at least a first ink layer, a second ink layer, a third ink layer, and a fourth ink layer are provided in order from the support side, and the thickness of the support is 7 μm or more and 12 μm.
μm or less, and the thickness of the fourth ink layer is 4 μm or more and 9
A heat-sensitive transfer material having a particle size of .mu.m or less and containing a colorant in at least the third ink layer.