JPH02167796A - Thermal transfer material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to 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 that provides a recorded image that has good printing quality and that 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 a transferred recorded image obtained by a thermal transfer recording method cannot be easily erased even if it is due to printing errors.

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 be performed using the thermal transfer material that transfers a recorded image onto a recording paper as is. 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.

Furthermore, JP-A-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. It is disclosed that recording is performed using a head with low thermal energy, 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, the above-mentioned conventional self-collecting thermal transfer materials have poor performance both as a transfer material for recording and as an erasing material for lift-off erasing the recorded image obtained on the recording medium. In addition to recording materials with high
It was extremely difficult to satisfy the requirements even for recording media with low smoothness. In particular, when erasing a recorded image, "reverse transfer" was likely to occur, in which the ink of the thermal transfer material was peeled off on the transferred recorded image side, whereas the erroneously recorded image should be peeled off on the side of the transferred recorded image.

Therefore, the present applicant previously proposed Japanese Patent Application No. 62-299046, which allows high-quality recorded images to be formed on both recording media with high surface smoothness and recording media with low surface smoothness. Moreover, the present invention provides a thermal transfer material that can be used for lift-off erasing using the thermal transfer material as it is.

However, there is still room for improvement in the heat-sensitive transfer material proposed by the present applicant.

In particular, there has been a desire for a heat-sensitive transfer material that can form a recorded image and perform lift-off erasure without any trouble even in an extremely low-humidity environment.

When the humidity of the usage environment is low, the recording paper becomes dry and its elasticity decreases. For this reason, when the ink layer of the thermal transfer material is transferred to the recording paper, the convex parts on the surface of the recording paper will deeply (embed) into the ink layer, and even if you try to peel off and erase the erroneously recorded image, it will be difficult to peel off and reverse transfer will occur. The problem was that it was easy.

The present invention is a thermal transfer method that can obtain recorded images with high print quality and lift-off erasability not only for recording media with high surface smoothness, but also for recording media with low surface smoothness. The purpose is to provide materials.

Another object of the present invention is to provide a thermal transfer material that provides a recorded image with good print quality and that can be lifted off and erased not only under a normal environment but also under a low humidity environment.

[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 on a support in this order from the support, and the first ink layer is made of water-soluble polyester resin. The second ink layer is a layer that is divided during heating recording, and the third ink layer and the fourth ink layer are layers that have a thermoplastic resin as a main component. In addition, the first ink layer is a layer containing water-soluble polyester resin as a main component, the second ink layer is a layer containing water-soluble polyester resin and is a layer that is separated during heating recording, and the third ink layer and the third ink layer are The fourth ink layer is characterized by being a layer containing thermoplastic resin as a main component.

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

As shown in FIG. 1, the thermal transfer material 1 of the present invention has a support 2.
Above, from the support side, at least a first ink layer 3, a second ink layer 4, a third ink layer 5, and a fourth ink layer 6.
are layered one after another. The first ink layer 3 firmly adheres to the support 2 without being separated either at the interface with the support 2 or inside thereof even during recording by heating. The first ink layer 3 is not substantially transferred to the recording medium 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 transferred to the recording medium. Make it easier. However, the non-heated portion of the second ink layer 4 firmly adheres to the first ink layer 3 and the third ink layer 5, and prevents the ink layer 5 from being transferred to the recording medium. A transferred recorded image corresponding to the heating pattern is formed by the contrast between the heated portion and the non-heated portion.

The third ink layer 5 and the fourth ink layer 6 are made of a binder material containing resin as a main component. The ink layer is placed in such a way that the ink layer just bridges the gap, and the ink layer is transferred so as to cover the concave portions of the recording medium.

To perform transfer recording on a recording medium using the thermal transfer material 1 of the present invention, immediately after heating the thermal transfer material 1 of the present invention in a pattern, and before the strength of the second ink layer 4 becomes sufficiently strong. To,
By peeling off the thermal transfer material 1 from the recording medium, the second
A recorded image is formed on the recording medium by the ink layer 4, and after the thermal transfer material 1 is brought into contact with the recorded image on the recording medium and heated, the strength of the second ink layer 4 is sufficient. By peeling the thermal transfer material l from the recording medium when the temperature becomes strong, the recorded image on the recording medium is peeled off and erased.

Now, as mentioned above, the first ink layer 3 is firmly adhered to the support 2 even during recording by heating, and when peeling off an erroneously recorded image (after heating, the second ink layer 4 has sufficient strength). (when the ink layer becomes strong) is also firmly adhered to the second ink layer 4 and the support 2. Therefore, the erroneously recorded image on the recording medium can be peeled off without being reversely transferred. As a material constituting the first ink layer 3, polyester resin is very preferable.

Among them, water-soluble polyester resins can be preferably used for the following reasons.

That is, in order to improve the sharpness of the transferred recorded image (that is, the edges of the recorded image are sharply cut without being wavy), the second ink layer 4. It is preferable that the third ink layer 5 and the fourth ink layer 6 are coated with a water-based emulsion so that the particulate nature of the emulsion remains. In particular, the third ink layer 5 and the fourth ink layer 6 are transferred so as to increase the film strength of the heated part and bridge the convex parts on the surface of the recording medium, so the heated part of the ink layer and the non-heated part of the ink layer are different from each other. It is necessary that the film strength varies greatly depending on the area. For this reason, it is desirable to leave particulate properties in the non-heated portions of the ink layer so that the ink layer can be sharply cut at the boundary between the heated and non-heated portions.

On the other hand, when removing and erasing an erroneously recorded image, each ink layer must be firmly adhered to each other in order to prevent reverse transfer from occurring.

Therefore, if a water-soluble polyester resin is used for the first ink layer 3, each ink layer will be coated with an aqueous system, and the adhesive strength between each ink layer will be improved. In other words, the first
By using a water-soluble polyester resin for the ink layer 3, not only can erroneously recorded images be peeled off and erased without causing reverse transfer, but also sharply recorded images can be obtained.

The water-soluble polyester resin used in the present invention is, for example, 9
Preferred is a polyester resin that can be dissolved in 5 g or more (more preferably 10 g or more) in 100 g of water at 0°C to give an aqueous solution or emulsion at 25°C after cooling.

Note that a solvent-soluble binder solution may be mixed into the coating liquid for coating the ink layer as long as it does not impair the particle nature of the emulsion or destroy the emulsion.

The content of the water-soluble polyester resin contained in the first ink layer 3 is preferably 70% or more and 100% or less, and more preferably 90% or more and 100% or less.

The weight average molecular weight of the water-soluble polyester resin is 5.00
It is preferably 0 or more, more preferably 8,000 or more. If the weight average molecular weight is too small, the cohesive force of the first ink layer 3 will be smaller than the cohesive force of the second ink layer 4 during heating (printing) or heating and cooling (erasing), resulting in defective recorded images or This is because reverse transcription is likely to occur. If the weight average molecular weight is too large, it will be difficult to dissolve the water-soluble polyester resin in an aqueous solvent, and dissolution will take a long time, which is not preferable. Therefore, the weight average molecular weight is preferably 30,000 or less, more preferably 25,000 or less.

Further, the glass transition point of the water-soluble polyester resin used in the first ink layer 3 is preferably 30°C or lower, more preferably 25°C or lower. If the glass transition point is too high, flexibility will decrease,
As a result, the adhesion between the support 2 and the first
Reverse transfer may occur due to interfacial peeling of the ink layer 3. Furthermore, if the glass transition point is lower than 0° C., it becomes sticky and difficult to handle, but this is not particularly limited.

The weight average molecular weight here refers to the value measured by GPC (resin was dissolved in dimethylformamide and analyzed by liquid chromatography (manufactured by Shimadzu Corporation)), and the glass transition point was measured by differential scanning calorimetry (DSC). value (
Measured by Perkinelmer DSC-7. Heating rate 5
°C/min, endothermic peak).

As the water-soluble polyester resin, glycols (HO
-R, -0H) or polyester glycol with a hydroxyl group at the end, and dicarboxylic acids (HOOC-R2-CO
OH) and monomers containing a sulfonic acid group or a carboxylic acid group necessary for water solubilization are preferably used.

Examples of glycols include ethylene glycol, propylene glycol, 1.3-propanediol, 2.
4-dimethyl-2-ethylhexane=■・3-diol, 2,2-dimethyl-1,3-propanediol, 2-
Ethyl-2-butyroute 3-propanediol, 2-ethyl-2-isobutyroute 3-propanediol, 1.
3-butanediol, 1,4-butanediol, l・5
-bentanediol, l・6-hexanediol, 2・
2,4-trimethyl-1,6-hexanediol, 1◆
2-Cyclohexane dimetatool, 1,3-cyclohexane dimetatool, 1,4-cyclohexane dimetatool, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4'-thiodidiol Phenol, 4.4'
- methylene diphenol, 4,4'-(2-norbornylidene)diphenol, 4,4'-dihydroxybiphenol, 0-lm- and p-dihydroxybenzene,
4,4'-isopropylidenediphenol, 4,4'-
Isopropylidene bis(2,6-dichlorophenol)
, 2,5-naphthalenediol and p-xylene diol, alkylene glycols such as copolymers that can be produced from two or more of the above-mentioned diols, and polyethylene glycol [general formula H (-OCH2CH2)]
rlOH.

n=2-10] and mixtures thereof are used.

Examples of dicarboxylic acids include oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, geltaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2.2
-dimethylglitaric acid, azelaic acid, sebacic acid,
Fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopencunedicarboxylic acid, 1,4
- Cyclohexanedicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, 2,5-norbornanedicarboxylic acid, 1,4-naphthalic acid, 4,4'-oxybenzoic acid, diglycolic acid, thiodipropionic acid and 2,5
- Naphthalene dicarboxylic acid and the like.

However, "dicarboxylic acid" includes acid anhydrides, esters, and acid chlorides corresponding to the above-mentioned acids.

Examples of the dicarboxylic acid monomer containing a sulfonic acid group or a carboxylic acid group necessary for water solubilization include sodium sulfophthalic acid, sodium sulfophthalic acid, potassium sulfophthalic acid, potassium sulfoisophthalic acid,
or sulfonic acid group-containing aromatic compounds such as esters thereof, 1,2,4.5-pentanetetracarboxylic dianhydride (pyromellitic anhydride), 1,2,3.4
-Butanetetracarboxylic dianhydride, 1,2,3.4-
Pentanetetracarboxylic dianhydride, 3.3', 4
．． 4'-benzophenonetetracarboxylic dianhydride,
5-(2,5'dioxotetrahydrofurfuryl)-3
-Methyl-3-cyclohexene-1,2-dicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, 2
, 3゜6.7-naphthalenetetracarboxylic dianhydride,
Ethylene glycol bistrimelitate dianhydride, 2.
' , 3,3'-diphenyltetracarboxylic dianhydride, thiophene-2,3,4,5 tetracarboxylic dianhydride, and other tetracarboxylic dianhydrides can be used.

The content of dicarboxylic acid containing a sulfonic acid group and a carboxylic acid group for water solubilization is 5 to 100 mol, more preferably 7 to 30 mol, per 100 mol of dicarboxylic acids (HOOC-R2-COOH). is preferred.

In addition, titanium oxide, clay,
Fillers such as zinc white and alumina hydrate, plasticizers, stabilizers, surfactants, etc. can also be appropriately mixed and used.

In making water-soluble polyester resin water-soluble, it is possible to use water and other solvents together as a solvent, but
The proportion of water in the solvent is preferably 50% or more, more preferably 65% or more, based on the total solvent. Other solvents that can be used include cellosolves (eg, ethyl cellosolve) and alcohols (ethyl alcohol, isopropyl alcohol).

The second ink layer 4 is preferably one that sharply melts when heated. Therefore, it is preferable that the second ink layer 4 has a melting point of 50° C. or higher and a melt viscosity of 500 cps or lower at 150° C. due to sharp melt properties. As the material constituting the second ink layer 4, the following materials are preferred, and waxes are particularly preferred.

Examples of the above-mentioned waxes include natural waxes such as vegetable waxes such as carnauba wax, candelilla wax, rice wax, and Japanese wax, mineral waxes such as ceresin wax and montan wax, and derivatives thereof, such as montan wax derivatives. Examples include acid wax, ester wax, and partially saponified ester wax. Petroleum waxes include paraffin wax and microcrystalline wax. 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 referred to in the present invention is measured using a Rotovisco RV12 type rotational viscometer (rotor used: PK-1-0, manufactured by West German Haake).
, 3).

Titanium oxide may also be added to the waxes mentioned above, if necessary.

Fillers such as clay, zinc, alumina hydrate, plasticizers,
A second ink layer 4 is formed by appropriately mixing a surfactant, a stabilizer, etc.
It is also possible to do this.

The third ink layer 5 and the fourth ink layer 6 are made of a binder material whose main component is a thermoplastic resin (in the present invention, the binder material refers to components other than the colorant among the components constituting the layers).
Even on a recording medium with low surface smoothness, it can transfer images by just bridging the convex portions on the surface of the recording medium. Furthermore, the third ink layer 5 contains a colorant. However, it is preferable that the fourth ink layer 6 does not contain a colorant.

This is because the fourth ink layer 6 is a layer that comes into contact with the recording medium, so if it contains a large amount of colorant, correction marks may remain even after peeling and erasing.

The binder material used for the third ink layer 5 includes thermoplastic resins such as polyolefin resin, polyamide resin, polyester resin, epoxy resin, polyurethane resin, polyacrylic resin, polyvinyl chloride resin,
Elastomers such as cellulose resin, polyvinyl alcohol resin, petroleum resin, phenol resin, polystyrene resin, vinyl acetate resin, natural rubber, styrene butadiene rubber, isoprene rubber, chloroprene rubber, polyisobutylene, bolybdenum, etc. is preferably used. The content of the thermoplastic resin is preferably 50% or more, more preferably 70% or more based on the binder material. Binder materials may also include natural waxes other than resins such as spermaceti wax, beeswax, lanolin, carnauba wax, candelilla wax, montan wax, and ceresin wax, petroleum waxes such as paraffin wax and microcrystalline wax, oxidized waxes, and esters. Synthetic waxes such as wax, Fischer-Tropsch wax, and polyethylene wax, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose, and fatty acids of sorbitan. It is preferable to use an appropriate mixture of esters such as esters, amides such as oleylamide, plasticizers, and oils such as mineral oil and vegetable oil.

The content of the colorant contained in the third ink layer 5 is 3 to 9
0%, more preferably 5-80%, especially 10-80%. Furthermore, if necessary, in addition to colorants, fine metal powder, inorganic powder,
Additives such as fillers made of metal oxides or the like may be added as appropriate.

As the colorant contained in the third ink layer 5, for example,
Carbon black, nigrosine dye, lamp black, Sudan black SM, first yellow, benzidine
Yellow, Pigment Niro, India First Orange, Irgazine Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR.

Pigment Orange R1 Linole Red 2G.

Lake Red C10-Damine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B1
Phthalocyanine Green, Oil Yellow GG, Zabon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiblast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumiblast Orange G1 Orazole Brown G1 Pomelo First Scarlet CG, Eizenspiron・Red・
BEN, Oil Pink OP1 Victoria Blue F4R,
One or more known dyes and pigments such as Fastgen Blue 5007, Sudan Blue, and Oil Peacock Blue can be used.

As the binder material used for the fourth ink layer 6, the above-mentioned material for the third ink layer 5 can be used as is. In the case of the fourth ink layer 6 as well, the thermoplastic resin is contained in the binder material in an amount of 50% or more relative to the binder material.
It is preferable to contain 0% or more.

Although it is possible to include a coloring agent in the fourth ink layer 6, adding an excessive amount is not preferable as it may cause erasure residues. When the fourth ink layer 6 contains a colorant, the content of the colorant is preferably 5% or less, 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,
This can be achieved by appropriately changing the molecular weight, etc., but it is desirable that the cohesive force 9 molecular weight be high in order to obtain good transferability to a recording medium with low surface smoothness. From this point, the third
As the material for the ink layer 5 and the fourth ink layer 6, in particular, polymer materials containing olefin as a main component, such as low molecular weight polyethylene oxide, ethylene-vinyl acetate copolymer, vinyl acetate-ethylene copolymer, ethylene-acrylic Acid copolymers, ethylene-methacrylic acid copolymers, ethylene-acrylic acid ester copolymers, etc., polyamides,
It is preferable to use polyester as the main component.

As the support 2, conventionally known films can be used as they are, and for example, films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetic acid cellulose, polyamide, polyimide, etc. can be suitably used. In particular, it is preferable to use a polyester film for the support 2 from the viewpoint of adhesiveness with the first ink layer 3.

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
By providing a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc., the heat resistance of the support can be improved, or it is possible to improve the heat resistance of the support. It is also possible to use other support materials.

The total thickness of the thermal transfer material of the present invention is preferably 10 to 30 μm, preferably 15 to 25 μm. The thickness of the support is 3 to 1
5 μm 1 preferably 4.5 to 15 μm 1 more preferably 6 to 12
μm is good. The thickness of the 11th second and third ink layers is 0
．． The thickness of the fourth ink layer is preferably 5 to 3 μm, more preferably 1 to 2.5 μm, and the thickness of the fourth ink layer is preferably 3 to 10 μm, and more preferably 4 to 8 μm.

In the above description, the first ink layer 3 uses a water-soluble polyester resin, but the second ink layer 4 can also contain a water-soluble polyester resin. Second
By containing the water-soluble polyester resin in the ink layer 4, the second ink layer 4, the first ink layer 3, and even the second
Adhesion between the ink layer 4 and the third ink layer 5 can be obtained, and reverse transfer during peeling and erasing can be more strongly prevented.

In this case as well, the second ink layer 4 is melted by heating and undergoes cohesive failure, thereby serving to separate the third ink layer 5 and the fourth ink layer 6 from the support 2 and the first ink layer 3.

For this reason, it is preferable that the second ink layer 4 mainly contains waxes having a low cohesive force when heated and a water-soluble polyester resin.

The amount of water-soluble polyester resin contained in the second ink layer 4 is 45% or less, and more preferably 40% or less of the second ink layer 4.
% or less is preferable.

If the content of water-soluble polyester resin is too small, the first
The adhesive force between the ink layer 3 and the second ink layer 4 decreases. If the amount of water-soluble polyester resin is too large, the effect of inhibiting reverse transfer will be sufficiently exhibited, but the cohesive force of the second ink layer 4 will increase when heated, making printing thinner and more likely to cause print chipping.

The glass transition point of the water-soluble polyester resin contained in the second ink layer 4 is preferably 30° C. or lower for the same reason as the polyester resin constituting the first ink layer 3. Further, the weight average molecular weight of the water-soluble polyester resin contained in the second ink layer 4 is preferably in the range of 5,000 to 25,000, more preferably in the range of to, ooo to 20,000.

When the weight average molecular weight is less than 5,000, the effect of adding water-soluble polyester to the second ink layer 4 is weak (,25
,000, print defects are likely to occur.

As the water-soluble polyester resin used for the second ink layer 4, the same one as the water-soluble polyester resin contained in the first ink layer described above can be used.

In addition to the water-soluble polyester resin, the second ink layer 4 may contain waxes and further thermoplastic resins. As the waxes contained in the second ink layer 4, waxes previously fried as the waxes used in the second ink layer 4 can be used as they are. When the second ink layer 4 contains a thermoplastic resin, if the thermoplastic resin is too large, the cohesive force of the second ink layer 4 becomes too high. Further, it is preferably 10% or less. The second ink layer 4 is preferably composed of a water-soluble polyester resin and a wax, and preferably does not contain a thermoplastic resin. In addition to the water-soluble polyester, the second ink layer 4 contains components other than the water-soluble polyester from the viewpoint of sharp melting properties, that is, waxes or waxes containing a thermoplastic resin, preferably having a melting point of 50°C or higher, and a melt viscosity at 150°C. is preferably 500 cps or less.

Above, the thermal transfer material of the present invention has been described using as an example the ink layer having a four-layer structure as shown in FIG.
And the fourth ink layer may be further functionally separated so that the total layer structure is five or more layers. For example, the fourth ink layer may be a layer that exhibits adhesive strength to the recording medium when heated;
It is effective to separate the functions into a layer that exhibits film-forming properties when heated and bridges between the convex portions on the surface of the recording medium, and to form the entire ink layer into a five-layer structure.

Next, a thermal transfer recording method using the thermal transfer material of the present invention will be explained, taking as an example the case where the thermal transfer material 1 shown in FIG. 1 is used.

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 support 2 side by the heating element 9 of the thermal recording head 8. Immediately after applying this thermal energy and before the strength of the second ink layer becomes sufficiently strong (preferably 20 m5 e after applying thermal energy, more preferably 10 m5 e
c.) Peeling off the thermal transfer agent from the recording medium. 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 decreases, making cohesive failure extremely likely.

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.

Also, 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 heating element 9 of the thermal recording head 8 is placed in the same area as the transferred recorded image 11 or in a larger area 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 in the same manner as 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 (preferably 50 msec after the application of thermal energy)
c, more preferably 100 m5ec.

During the above steps), 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 II also increases, and the transferred recorded image 11 is
lift-off erasure is a distant relative.

The present invention will be explained more specifically with reference to examples below. do.

[Examples 1 to 4] Coating liquid (coating liquid 1) Terephthalic acid isophthalic acid ethylene glycol polyethylene glycol (weight average molecular weight 1540) Dodecanedioic acid 5-sulfoisophthalic acid sodium coating 1'' (coating liquid 2) Terephthalic acid Isophthalic acid dodecanedioic acid (HOOC-(CH2), o-C00H) Ethylene glycol 1.4 Butanediol 5- Sodium sulfoisophthalate 29% 25 〃 20 〃 6 〃 15 〃 5 〃 26% 22 〃 20 〃 12 // 15” 5 〃 Transparent” (Coating liquid 3) Terephthalic acid 26% Isophthalic acid 22//Dodecanediic acid
20〃Ethylene glycol
14//propylene glycol
13/15-Sodium sulfoisophthalate
5 tt 1st Surface Treatment 1” (Coating Solution 4) Terephthalic acid 26% Isophthalic acid 22//Dodecanedioic acid
201/ethylene glycol
12//1.4 butanediol
15115-Sodium sulfoisophthalate
5nA water-soluble polyester resin was obtained using the raw material compositions and monomer charging compositions shown in Prescriptions 1 to 4 above.

Weight average molecule II of the obtained water-soluble polyester resin
(Mw) and glass transition point (Tg) are as shown in Table 1 below.

The water-soluble polyester resins of formulations 1 to 4 were dissolved in a mixed solvent of water/isopropyl alcohol = 55/20 to obtain polyester resin coating liquids 1 to 4 with a nonvolatile content of 25%.

Nobuyoshi” (Coating liquid 5) Carnauba wax aqueous dispersion 100 parts Nobuyoshi” (
Coating liquid 6) Ethylene vinyl acetate copolymer emulsion
22.7 parts (base range Ml: 150, vinyl acetate content = 28% non-volatile content: 44%) Carbon Plaque aqueous dispersion
60.0 parts (nonvolatile content: 25%) Water 17.3 parts Nobuyoshi 1 (coating liquid 7) Ethylene vinyl acetate copolymer emulsion
54.5 parts (base range MI: 150. Vinyl acetate content = 28% non-volatile content: 44%) Ethylene-methacrylic acid-styrene copolymer emulsion 32.0 parts (ethylene content = 88%, non-volatile content: 25%) )water
13.5 parts of the above formulations 5 to 7 were uniformly mixed using a propeller stirrer to obtain coating liquids 5 to 7.

Coating liquid 1 was applied onto a 9 μm thick polyethylene terephthalate film using an applicator and dried with hot air to form a first ink layer. Coating liquids 5, 6.7 are sequentially applied and dried on the first ink layer, and the second, third and third ink layers are coated and dried. Thermal transfer material (I) of the present invention by forming a fourth ink layer (Example 1)
I got it. Furthermore, in the same manner, coating liquid 2, 5, 6.7 (Example 2), coating liquid 3, 5, 6°7 (Example 3), coating liquid 4, 5, 6.7 (Example 2) Example 4) was applied sequentially,
After drying, the thermal transfer material (■) (Example 2), the thermal transfer material (
■) (Example 3) and a thermal transfer material (■) (Example 4) were obtained. The thickness of each layer of the thermal transfer material is 1.0 μm for the first and second ink layers and 1.58 μm for the third ink layer.
The m1 fourth ink layer was 5.0 μm.

[Comparative Example 1] Byron 30S (manufactured by Toyobo Co., Ltd.) polyester resin solution Tg: 6°C, number average molecular weight approximately 20,000 was diluted with methyl ethyl ketone to obtain coating liquid 8 with a non-volatile content of 15%. Coating liquids 8.5° and 6.7° were sequentially applied and dried in the same manner as in Examples 1 to 4 to obtain a thermal transfer material (■).

Next, the thermal transfer materials obtained in the above examples and comparative examples (■) ~
(V) was cut to a width of 8 mm, and an electronic typewriter 3P400X manufactured by Canon Co., Ltd. was used. The recording material was bond paper with low smoothness (Beck smoothness of 2 to 3 seconds) and smooth paper. Typewriter paper T-2 manufactured by Life Co., Ltd. with high quality
1 (Beck smoothness of 40 seconds) was used to evaluate recording and lift-off erasure. Said typewriter-5P400
In X, a heater was 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, for lift-off erasure, the thermal transfer materials (I) to (V) are placed in the thermal correction tape storage section of the 5P400X.
By loading it, it becomes possible to evaluate it.

Prior to the erasing performance, the printing performance of the thermal transfer materials (I) to (V) was evaluated, and very good recorded images with good "cutting" were obtained in all of them.

Erasing performance was evaluated at room temperature (25°C) and room humidity (50% RH).
Evaluations were made in an environment of room temperature and low humidity (10% RH).

This is because the properties of paper, which is a recording medium, change very sensitively, especially its surface condition, due to changes in humidity. The evaluation results are shown in Table 2.

Table 2 [Examples 5 to 9] Water-soluble polyester resin coating liquid 2 and carnauba wax aqueous dispersion (non-volatile content: 30%, of which 4% surfactant) were mixed so that the non-volatile content ratio was as shown in Table 3. The mixtures were uniformly mixed using a propeller stirrer to obtain coating solutions 9 to 13.

Coating liquids 9, 6 and 7 were sequentially applied on the 3rd surface layer and dried with hot air. Third. A fourth ink layer was formed to obtain a thermal transfer material (Example 5). The thickness of each layer was 1.0 μm for the first and second ink layers, 1.5 μm for the third ink layer, and 5.0 μm for the fourth ink layer.

Coating liquid 2. 10. 6.7 (Example 6)
, coating liquid 2. 11.6.7 (Example 7), Coating liquid 2.
12°6.7 (Example 8), coating liquid 2. 13.6.
7 (Example 9) was sequentially coated and dried to form a thermal transfer material ■(
Example 6), ■ (Example 7), ■ (Example 8), and X (Example 9) were obtained.

Coating liquid 2 was applied onto a 9 μm thick polyethylene terephthalate film using an applicator and dried with hot air to form a first ink layer. First Ink The above thermal transfer materials (VI) to (XI) were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4. In Table 4, the evaluations of ◎, ○, and × are the same as those in Table 2.

Table 4 [Effects of the Invention] As explained above, the thermal transfer material of the present invention uses a water-soluble polyester resin in the first ink layer and, if necessary, a water-soluble polyester resin in the second ink layer. , the adhesiveness between the first ink layer and the support and the adhesion between the first ink layer and the second ink layer are excellent. For this reason,
According to the thermal transfer material of the present invention, no erasing failure occurs due to reverse transfer during erasing.

Further, in the thermal transfer material of the present invention, since the third and fourth ink layers contain thermoplastic resin as a main component, excellent recorded images can be obtained even on recording materials with poor surface smoothness.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of the thermal transfer material of the present invention, FIG. 2 is a schematic sectional view illustrating a thermal transfer recording method using an example of the thermal transfer material of the present invention, and FIGS. 3 and 4. FIG. 3 is a schematic cross-sectional view illustrating a beam lift-off erasing method. 1...Thermal transfer material 2...Support 3...First ink layer 4...Second ink layer 5...Third ink layer 6...Fourth ink layer 7...Subject Recording body 8...Thermal recording head 9...Heating element 10...Peeling member 11...Transfer recorded image

Claims (2)

[Claims] (1) In a thermal transfer material having at least a first ink layer, a second ink layer, a third ink layer and a fourth ink layer on a support in order from the support side, the first ink layer mainly contains a water-soluble polyester resin. 1. A thermal transfer material, wherein the second ink layer is a layer that is separated during heating recording, and the third ink layer and the fourth ink layer are layers containing a thermoplastic resin as a main component. (2) In a thermal transfer material having at least a first ink layer, a second ink layer, a third ink layer and a fourth ink layer on a support in order from the support side, the first ink layer mainly contains a water-soluble polyester resin. The second ink layer is a layer containing a water-soluble polyester resin and is a layer that is separated during heating recording, and the third ink layer and the fourth ink layer are layers containing a thermoplastic resin as a main component. A heat-sensitive transfer material featuring: