JPS63257686A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer material having good preservability and forming a durable transfer recording image, by providing first and second layers on a supporting member and adding aminoplast to one layer while an acid catalyst in the other layer. CONSTITUTION:Thermally fusible first and second layers 13, 14 are provided sequentially on a supporting material 12, where aminoplast resin is added in any one of the first and second layers while an acid catalyst is added in the other layer. Heat to be produced during recording or fusing/mixing effect between respective layers cause mixing of aminoplast resin and acid catalyst so as to start hardening reaction. Storing performance is improved because hardening reaction is not promoted prior to recording. Hadening reaction can be promoted as time elapses after recording or through secondary processing such as heating or pressurizing which are carried out after recording so as to increase film strength and cohesion of recorded image thus increasing adhesion between aminoplast resin and recording medium such as paper, resulting in improvement of fixedness and durability of recorded image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thermal transfer material used in a thermal transfer recording method.

[Conventional technology]

In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and devices suitable for each information processing system have also been developed and adopted. One such recording method is the thermal recording method.
The equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability, and has recently been widely used.

However, among the recording papers used in thermal recording methods.

Ordinary thermal recording paper is a color-forming processed paper that contains a color former and a color developer, so it is expensive, and records can be tampered with, and the recording paper is easily damaged by heat or organic solvents. It has disadvantages such as poor recording stability, such as color development and discoloration of recorded images in a relatively short period of time.

A thermal transfer recording method has recently been attracting particular attention as a method that maintains the advantages of the above-mentioned thermal recording method and compensates for the drawbacks associated with the use of thermal recording paper.

This thermal transfer recording method generally involves the following steps as shown in FIG.
A heat-sensitive transfer material 23 is used, in which a heat-transferable ink layer 22 formed by dispersing a coloring material in a heat-melting material is melt-coated on a sheet-like support 21. The ink layer 22 is superimposed on the recording medium so as to be in contact with the recording medium, and heat is supplied from the support side of the thermal transfer material to transfer the melted ink layer to the recording medium. A transfer recording image is formed thereon in accordance with the shape of heat supply. According to this method, it is possible to maintain the above-mentioned advantages of the thermal recording method, use plain paper as a recording medium, and eliminate the above-described disadvantages associated with the use of thermal recording paper.

However, conventional thermal transfer recording methods are not without drawbacks.

One of them is that the thermal transfer ink layer of conventional thermal transfer materials is
As mentioned earlier, since the colorant is dispersed in a heat-melting material, this heat-melting material has reversible heat-melting properties and is relatively brittle, so it cannot be easily melted after heat transfer. The recorded images are also brittle and prone to scratches, and may soften or remelt at high temperatures. Therefore, if the surface of the recording section is rubbed.

They are prone to staining and peeling, and if the recording medium is stored at high temperatures, the recorded image may bleed, and if stacked one on top of another, phenomena such as set-off occur.

For this reason, a heat-sensitive transfer material has been proposed in which the heat-melt ink layer contains a compound that causes reactive cross-linking to improve durability, so that the durability of the ink layer is increased through reactive cross-linking over time after transfer. However, in this case, there was a problem in that reactive crosslinking occurred even before recording, which deteriorated the storage stability of the heat-sensitive transfer material and inhibited the transferability of the ink.

Furthermore, in recording using conventional thermal transfer materials, penetration of ink into the recording medium is essentially unavoidable, and it is impossible to correct erroneously recorded areas by peeling them off.

Therefore, it is desirable to have a type of thermal transfer material that allows the transferred recorded image to be corrected, but also prevents tampering with areas that do not require correction.

In addition, conventional thermal transfer recording methods have poor transfer recording performance.

In other words, print quality is greatly affected by the surface smoothness of the recording medium; good printing is performed on highly smooth recording media, but print quality is significantly degraded when recording media with low smoothness are used. It is.

However, even when using paper, which is the most typical recording medium, highly smooth paper is rather special, and ordinary paper has various degrees of unevenness due to entangled fibers. Therefore, in the case of paper with a large surface unevenness, the hot melted ink cannot be transferred to the entire recording area of the paper during printing, but penetrates and adheres only to the convex parts of the surface or the vicinity thereof, resulting in the edges and edges of the printed image being distorted. It may not be sharp or part of the image may be missing.

This will reduce print quality.

[Problems to be solved by the invention]

The present invention has been made to solve the above-mentioned conventional problems.

Accordingly, a first object of the present invention is to provide a heat-sensitive transfer material that can form a transferred recorded image that is thermally and mechanically durable and has good storage stability before recording.

A second object of the present invention is to provide a thermal transfer material that can provide a transferred recorded image that allows correction of erroneously recorded portions and does not require correction, or that can prevent falsification of normal recorded portions after correction. There is a particular thing.

A third object of the present invention is to provide a thermal transfer material that makes it possible to form a good transferred recorded image even on a recording medium with poor surface smoothness.

[Means for solving problems]

The heat-sensitive transfer material provided by the present invention has a support, and a heat-melting first layer and a second layer, respectively, in order from the support side, and the first layer and the second layer are heat-fusible. It is characterized in that one of the layers contains an aminoplast resin and the other layer contains an acid catalyst.

When thermal transfer recording is performed using the thermal transfer material of the present invention,
Due to the heat obtained during recording and the melt mixing effect between each layer, the aminoplast resin and acid catalyst contained separately mix,
The curing reaction begins. Therefore, the curing reaction does not proceed before recording, resulting in good storage stability, and the curing reaction progresses over time after recording or due to secondary treatments such as heating and pressurization that may be performed after recording. The film strength and cohesive force of the recorded image are increased, and the adhesion of the aminoplast resin to the recording medium such as paper is increased, which improves the fixability of the recorded image.

Improves durability.

In addition, immediately after recording, before the secondary treatment, and before the hardening of the diaminoplast resin has sufficiently progressed, the recorded image does not penetrate excessively into the recording medium, and the erroneously recorded portion is erased because it has film properties. Corrections such as re-recording are possible, and after curing progresses, it becomes difficult to peel off the recorded image, thus preventing falsification.

Moreover, since the heat-fusible layer is divided into two layers, the first layer and the second layer, it is easy to adjust the physical properties of each layer, especially the melt viscosity and cohesive force, which makes it possible to easily adjust the physical properties of each layer, making it easy to adjust the melt viscosity and cohesive force. It is also possible to make good records for.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. In the following description, "%" representing the 5-quantity ratio
” and “parts” are based on weight unless otherwise specified.

FIG. 1 is a schematic cross-sectional view in the thickness direction for explaining the structure of the thermal transfer material of the present invention.

As illustrated in FIG. 1, the thermal transfer material 11 of the present invention has a first layer 13 and a second layer 14, each of which is heat-fusible, on a support 12, usually in the form of a sheet.

As the support 12, conventionally known films and papers can be used as they are; for example, films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, nylon, polyimide, cellophane, parchment paper, etc. can be suitably used.

The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source during thermal transfer, but it is possible to selectively heat the first and second layers with laser light, for example. There are no particular restrictions when using a heat source. In addition, when heat is used, a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. is placed on the surface of the support that comes into contact with heat. The heat resistance of the support can be improved by providing
Alternatively, support materials that could not be used conventionally can also be used.

The first layer and the second layer can be made to exhibit heat-melting properties by using essential components such as the aminoplast resin, but they can be made to have heat-melting properties by containing other appropriate heat-melting materials in combination. Ninth, it is desirable that the desired physical properties such as the above-mentioned melt viscosity and cohesive force can be easily expressed to a desired degree.

In this case, the heat-melting materials used for the first ink layer and the second layer are desirably selected in consideration of the physical properties such as the cohesive force and melt viscosity of each layer as described above.

As an example, by adopting the following selection criteria, it is possible to obtain a thermal transfer material that has excellent recording transferability, printing quality, etc., and further improves transferability for recording media with poor surface smoothness. can.

That is, the first layer needs to be easily peeled off from the support when heated. To achieve this, the interfacial shearing force at the interface between the heated part and the unheated part must be small;
The cohesive force of the first layer needs to be low so that the entire first portion of the heated area is transferred to the recording medium.

The second layer may be peeled off when the first layer is peeled off from the support, so the cohesive force may be large. Rather, the layer of cylinder 2 may excessively permeate into the recording medium after being transferred to the recording medium. This causes variations in the density of the recorded image, making it impossible to obtain clear prints and making it impossible to correct erroneous recordings, so it is preferable that the cohesive force and melt viscosity of the second layer are large.

The preferred physical properties of the first layer and the second layer vary depending on conditions such as the amount of heat applied during heat application and the pressure applied to the recording medium, but it is generally desirable that the physical properties satisfy the following physical properties conditions.

That is, for the reasons mentioned above, the cohesive force of the first layer is usually 2 to 100 at 20°C, and the cohesive force of the second layer is 30
A range of ~300 kQ7cm is suitable.

In addition, the outflow start temperature (flow tester CFT manufactured by Shimadzu Corporation)
-500A type, load 30kg, heating rate 2'C/m
It refers to the temperature that gives an apparent viscosity of 5 x 103 voids under the conditions of in. ), the first layer is 40℃~120℃, the second layer is 40℃~120℃
It is preferable that the temperature of the layer is in the range of 50 to 150°C. The melt viscosity (at 150°C) measured by a rotational viscometer is the first
The layer is 10-10,000 centivoids, 20-60%
00 centivoices is preferable.

As mentioned earlier, the function of the second ink layer is that it does not penetrate deeply into the paper, but uses the small points of contact with the paper to form a film over the entire dot or between the dots. It is preferable to form the film and transfer it onto uneven paper in the form of a lid, in which case the melt viscosity is 50° C.
0 centiboise to 2,000,000 centiboise, especially 2
000 centivoise to 1,000,000 centivoise is suitable. If the melt viscosity is too low, the ink will permeate from the place where it comes into contact with the convex part of the recording material paper, making it difficult for the ink to be cut off at that part. If the melt viscosity is too high, the adhesion to the recording material will tend to decrease. Become.

When selecting based on these criteria, suitable heat-melting materials to be used for the first layer include natural waxes such as wax wax, beeswax, lanolin, carnauba wax, candelilla wax, and montan wax, and paraffin wax. , microcrystalline waxes, oxidized waxes, ester waxes, synthetic waxes such as low molecular weight polyethylene, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, fromene acid, behenic acid,
Using higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose, and amides such as turbialinamide and oleinamide as the main ingredients, polyolefins can be used within the range that satisfies the conditions of cohesive force and melt viscosity. Resin, polyamide resin, polyester resin, epoxy resin, polyurethane resin, acrylic resin, vinyl chloride resin, cellulose resin, polyvinyl alcohol resin, petroleum resin, phenol resin, styrene resin, natural rubber .

Elastomers such as styrene-butadiene rubber, imprene rubber, and chloroprene rubber, or oils such as mineral oil and vegetable oil may be appropriately mixed and used.

In addition, suitable heat-melting materials used for the second layer include polyamide resins, polyolefin resins, polyester resins, epoxy resins, polyurethane resins,
Acrylic resin, vinyl chloride/' series! The main components are elastomers such as oil, cellulose resin, polyvinyl alcohol resin, petroleum resin, phenolic resin, styrene resin, natural rubber, styrene-butadiene rubber, imprene rubber, and chloroprene rubber. A thermofusible material used as the main component of the first layer, a plasticizer such as tricresyl phosphate, dibutyl phthalate, mineral oil, vegetable oil, etc. may be appropriately mixed within the range that does not exempt the above viscosity cohesive force. It may also be used as

In addition, the said cohesive force means what was measured under the following conditions.

Measuring equipment: Tensilon TM-100 (manufactured by Toyo Baldwin) Measurement sample: Width 10 days x thickness 0.1-2 mm (tensile part) Gripping interval: 201 Tensile speed: 100 Wm1n Measurement temperature and humidity: 20°C 65% The aminoplast resin used in the present invention includes urea,
Prepolymers such as methylolurea, methylolguanamine, methylolmethimine, etc., which are derived from ureas such as thiourea, guanamines such as benzoguanamine and acetoguanamine, melamines, and aldehydes such as formaldehyde by condensation reactions, and the methylol It is obtained by reacting a compound with an alcohol such as methyl alcohol, ethyl alcohol, or butyl alcohol. These alkyl ether compounds may be used alone or in a mixture of two or more thereof. When the 5-aminoplast resin is used in combination with another heat-melting material, the amount is preferably in the range of 1 to 50 parts per 100 parts of the heat-melting material.

If it is less than 1 part, the desired effect cannot be obtained, and if it exceeds 50 parts, the cohesive force of the layer containing the aminoblast resin will decrease, which is not preferable.

In addition, as the acid catalyst used in the present invention, various typical inorganic acids, organic acids, acid salts, carboxylic acid esters, acid anhydrides, organic halides, amine hydrochlorides, urea derivatives, etc. can be used. It will be done. Specifically, acids such as hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, sulfamic acid, toluenesulfonic acid, acid salts such as ammonium chloride, ammonium sulfate, iron chloride, sodium phosphate, carboxylic acid esters such as dimethyl oxalate, Acid anhydrides such as maleic anhydride, phthalic anhydride, sodium monochloroacetate α,
Organic halides such as α'-dichlorohydrin, amine hydrochlorides such as etheramine hydrochloride and triethanolamine hydrochloride, urea derivatives such as salicylic acid urea adduct and stearic acid urea adduct are used.

In addition, the amount of acid catalyst used may be small because it is used to initiate the condensation reaction of the aminoplast resin.
In order to increase the probability of contact with the aminoplast resin mixed with the heat-fusible material, it is preferable to add it in a slightly permeable amount. That is, 0 parts for 100 parts of aminogellast resin.
．． 5 to 20 parts is preferred. If it is less than 0.5 parts, the desired effect cannot be obtained, and if it exceeds 20 parts, the cohesive force of the layer containing the acid catalyst will decrease, which is not preferable.

At least one of the first layer and the second layer contains a coloring material for coloring, if necessary. As a coloring material, carbon gela, ri.

Nigrosine dye, Lamp black, Sudan black 8M, Flukali Flu, First Nilow〇, Benzidine yellow, Hikmento yellow, Indo first orange, Irgazine red, Paranitroaniline, Do,
Toluidine, Carmine FB, Permanent Bordeaux FRB, Pigment Orange, Lysol Red 20° Lake, Do C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Hiku Mentoflu, Brilliant Green B, 7 Talocyanine Green, Oil Yellow G
G, f Bon First Yellow OGG, Kaya Set Y
963, Kayase,) YG, Sumiblast Yellow G,
Zapon Fast Orange Rn, Oil Scarle, To, Sumiplast Orange G, Orazole Brown B,
Pomelo First Scarlet OG, Eisenspiron Shido, BEH, Oil Pink OP, Victoria Blue F41't, First Gen Blue 5007, Sudan Blue, Oil Peacock Blue, etc. Various types used in the printing and recording fields. Both dyes and pigments can be used. These colorants.

Usually, for example, 3 to 45 parts per 100 parts of hot-melt material.
It can be used at a rate of 0 parts.

In the present invention, it is possible to erase and correct the recorded image before the curing reaction of the aminoplast resin has sufficiently progressed, but specific methods for erasing the recorded image include peeling with an eraser or adhesive tape. It will be done. As a reminder, the curing reaction of aminoplast resins is initiated by mixing with an acid catalyst due to the heat during bonding and the melt-mixing effect.
If the curing reaction does not progress sufficiently, the reaction is accelerated by heating, using a pressure roll, heating in an oven, irradiating light, or the like.

A secondary treatment may be performed to further harden the recorded image.

In order to obtain the heat-sensitive transfer material of the present invention, first, the above-mentioned heat-melting material 1 that can be used in the first ink layer, a colorant and a dispersant,
Various additives such as fillers are melted and kneaded using a dispersion device such as an attritor, or kneaded with an appropriate solvent to obtain a hot-melt, solution or dispersion ink, and this ink is applied onto a support. to form the first layer. Next, the second layer may be formed using the same formation method as that for the first layer as described above.

The thickness of the first layer, second layer, and layer obtained as described above is preferably in the range of 1 to 10 μm and 1 to 10 μm, respectively, and the thickness of the entire ink layer is preferably in the range of 2 to 20 μm. . Furthermore, the layers to which the epoxy resin and curing agent are added are either the first layer or the second layer,
The planar shape of the thermal transfer material of the present invention is not particularly limited, but it generally has a typewriter ribbon shape or a wide shape used in line printers, etc. It is used in the form of tape, etc. Further, for color recording, it is also possible to use a heat-sensitive transfer material in which heat-melting inks of several different tones are applied in stripes or blocks.

Further, the thermal transfer recording method using the thermal transfer material of the present invention includes:
This method is not particularly different from the conventional method, and recording media made of plain paper or the like are stacked so as to be in contact with the heat transferable ink layer of this heat-sensitive transfer material. After applying heat in a pattern according to a desired recording pattern using a method such as the above, the heat-sensitive transfer material and the recording medium may be dispersed.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Carbon Brass 10 parts Polyethylene wax (softening point 95°C) 60 g Ethylene-vinyl acetate copolymer (softening point 68°C) 30 parts The above-mentioned formula 7 triter was added and dispersed under heating, While heating the obtained carbon black dispersion to about 100°C, a toluene/xylene mixed solvent (mixing ratio 50150) was added to it.
) 400 parts were added, stirred vigorously, and then cooled to room temperature to obtain a fine dispersion of ink.

Next, 70.5 parts of ammonium P-toluenesulfonic acid was added to 100 parts of the above dispersion and mixed to obtain a first layer-forming coating solution.

The above first layer forming coating solution was dried and a sample was prepared.
When we measured the melt viscosity and cohesive force at 0°C, we obtained the following values.

Melt viscosity at 150°C 5200 centivoise cohesive force (20°C) 3 klVcm2 Next, vinyl acetate-ethylene copolymer 60 parts Molecular weight oxidized polyethylene 30 parts Paraffin wax, wax (softening point 80°C) 10 parts Each of the above components was added using an attritor. Disperse by heating.

400 parts of toluene/xylene mixed solvent (mixing ratio 50150) was added to this while heating it for about 100 CK, and after stirring vigorously, it was cooled to room temperature, and then 5 parts of butylated methylol melamine resin was added to 100 parts of the above dispersion. death,
A second layer-forming coating solution was obtained.

The second layer-forming coating liquid was dried and a sample was prepared, and the melt viscosity and cohesive force at 150°C were measured, and the following values were obtained.

Melt viscosity at 150°C: 53,000 centiboise Cohesive force: 20°C 60 kg (7 cm2) Then, on a polyethylene terephthalate film of %6 μm, the first layer-forming coating solution was applied using an applicator and dried to form a film with an average thickness of 31 Irn. A first layer was obtained.

Next, a second layer forming coating liquid is applied onto the first layer using an applicator and dried to form a second layer having an average thickness of 3 μm. I got the material.

When this thermal transfer material was printed on bond paper with a Peck smoothness of 12 seconds using Canoward 458, very good print was obtained with good clarity and print density and quality. Immediately after printing, the print could be erased by rubbing it with an eraser. Furthermore, after printing, the print was left at room temperature day and night, and then an attempt was made to erase it with an eraser in the same manner, but it could not be erased, confirming that the print had excellent fixation properties.

Comparative Example 1 Carbon plastic, 1 part carnaubawa, Kusu 50 parts paraffin wax,
40 parts of alcohol The mixture was heated and dispersed using the above-mentioned generating attritor to obtain an ink layer forming composition.

Melt viscosity at 150°C of the above ink layer composition and 2
When the cohesive force was measured at 0°C, the following values were obtained.

Melt viscosity at 150°C 40 centivoise cohesive force (20°C) 27.2 A thermal transfer material was obtained in the same manner as in the example, and a printing test was conducted on the thermal transfer material in the same manner as in the example. Compared to the smoothness of Pont MK, the print was unclear and a satisfactory print quality could not be obtained9. Furthermore, when the incorrect print was rubbed with an eraser immediately after printing, it was impossible to erase it.

〔Effect of the invention〕

According to the thermal transfer material of the present invention, a transferred recorded image having thermal and mechanical durability can be formed, and furthermore, the thermal transfer material has good storage stability before recording. Moreover,
In the transferred recorded image that is formed, it is possible to correct the erroneously recorded portion, and either no correction is required, or it is possible to prevent falsification of the correct recorded portion after the correction. Further, a good transferred recorded image can be formed even on a recording medium with poor surface smoothness.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view in the thickness direction for explaining the structure of a thermal transfer material of the present invention, and FIG. 2 is a conventional thermal transfer material. 11.23...Thermal transfer material, 12.21...Support. 13...First layer, 14...Second layer, 22...
・Thermal transferable ink layer.

Claims (1)

[Claims] On the support, from the support side, heat-fusible first
and a second layer, wherein one of the first layer and the second layer separately contains an aminoplast resin, and the other layer separately contains an acid catalyst. Thermal transfer material.