JPH01290497A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To record a matted image easy to see and beautiful, by providing a supercoolable adhesive layer and first and second ink layers, and setting the melt viscosity of the adhesive layer under the conditions of a specified supercooling time and specified temperature to be higher than that of the second ink layer. CONSTITUTION:The adhesive force F2 between first and second ink layers 4, 5 and the adhesive force F1 between the first ink layer 4 and a base 2 are so controlled that F1>F2 when the timing of releasing a recording medium and a thermal transfer material from each other after application of heat is earlier, whereas F1<F2 when the timing is later, and the first and second ink layers are provided with different tones. Thus, a supercoolable adhesive layer 3 between the first ink layer 4 and the base 2 is in a molten state even in the case of the later releasing timing, so that the first ink layer 4 forms a matted image. In the case of the earlier releasing timing, separation occurs in the inside part of the second ink layer 5. It is necessary that the melt viscosity of the adhesive layer at 150 deg.C, immediately upon application of heat, be higher than that of the second ink layer 5. In the case of the later releasing timing, the period of time required for the adhesive layer 3 to start being solidified after being once softened is preferably 0.5-100sec.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a two-color thermal transfer material for transferring two-color recorded images onto a recording medium made of plain paper or the like.

[Background technology]

The thermal transfer recording method has the general characteristics of the thermal recording method, such as the equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability. It is characterized by excellent image durability and has been widely used recently.

This thermal transfer recording method generally uses a thermal transfer material formed by coating a sheet-like support with a thermal transferable ink made of a heat-melting binder and a colorant dispersed therein. The ink layer 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 by a thermal head to transfer the melted ink layer onto the recording medium. A transferred recorded image is formed thereon according to the shape of heat supply.

Furthermore, there is a strong market demand for two-color printing while taking advantage of the advantages of the thermal transfer recording method, and various techniques for obtaining two-color printing have been proposed.

Conventionally, as a method for printing in two colors on plain paper using a thermal transfer recording method, Japanese Patent Application Laid-Open No. 148591/1983 discloses two heat-melting high-melting point printing methods in which different colorants are contained on a base material. Ink layer A and low melting point ink layer B are sequentially laminated from the base material side, and in the case of low heat applied energy, only the low melting point ink layer B is transferred onto the plain paper, and in the case of high heat applied energy, the heat melting ink layer is transferred onto the plain paper. A two-color thermal transfer recording element is disclosed which provides a two-color recorded image by transferring both A and B.

Furthermore, JP-A No. 59-64389 discloses a two-color thermal transfer ink in which an ink layer is provided on a base material, which is composed of an ink that melts and leaches when heated, and an ink that melts and peels off at a temperature higher than the melting and leaching temperature. The sheet is disclosed.

In these methods, two-color printing is performed by changing the temperature of the ink layer by changing the energy applied to the thermal head in two stages. However, when high energy is applied to raise the temperature of the ink layer to a high temperature, a relatively low-temperature area is created around the high-temperature area due to heat diffusion, so that the area printed at a high temperature is printed at a low temperature. This results in color fringes. Furthermore, when high energy is applied to the thermal head, it takes a relatively long time for the temperature to drop, so that trailing of colors printed at low temperatures tends to occur behind areas printed at high temperatures.

In addition, in both methods, there is a restriction that a material with a relatively low melting point must be used as an ink material for printing at a low temperature, resulting in problems such as background smearing and a decrease in storage stability.

As a technique for solving this drawback, the present applicant previously proposed a recording method in Japanese Patent Application Laid-open No. 137789/1983.

This recording method uses a heat-sensitive transfer material provided with at least first and second ink layers on a support, and after applying heat to the heat-sensitive transfer material, there is a time period during which the heat-sensitive transfer material and the recording medium are separated. In this method, the second ink layer is selectively transferred, or both the first and second ink layers are transferred onto the recording medium by controlling the ink layer.

This recording method makes it possible to solve various problems such as "fringing" and "tailing" in printing mentioned above.
Even in such a new two-color recording method, further improvement in print quality is desired. This improvement in print quality is achieved by, for example, making the print quality more homogeneous. In other words, when only the second ink layer is selectively transferred, the print is dull (so-called matte), whereas the first ink layer and Second
When both ink layers are transferred, when the first ink layer and the support are separated at the interface, the print becomes glossy. For this reason, on one sheet of recording paper, there is a mixture of erased and glossy prints, making the prints unsightly, but it has not always been easy to ensure that the print quality does not vary depending on the color.

[Object of the present invention]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a thermal transfer material that provides beautiful two-color printing with uniform print quality on plain paper.

[Summary of the invention]

As a result of intensive research, the inventors of the present invention found that
The thermal transfer material used in the recording method of No. 137789 has an adhesive layer, a first ink layer, and a second ink layer having at least supercooling properties on a support from the support side, and the supercooling time of the adhesive layer is is in the range of 0.5 to 100 seconds,
and by using an adhesive layer whose melt viscosity at 150° C. is higher than that of the second ink layer,
When transferring the first ink layer and the second ink layer together,
The gloss of the recorded image is eliminated by separating it within the adhesive layer.

"-" Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. In the following descriptions, "%" is used to express quantitative ratio.
” and “part” are based on the mold plate unless otherwise specified.

[Detailed description of the invention]

Referring to FIG. 1, a thermal transfer material 1 of the present invention has an adhesive layer 3 having supercooling properties, a first ink layer 4, and a second ink layer 5 in this order on a support 2.

In the thermal transfer material of the present invention, the first ink layer 4 and the second ink layer 4
The magnitude relationship between the adhesive force (F2) between the ink layers 5 and the adhesive force (Fl) between the first ink layer 4 and the support 2 is determined by the timing of peeling off the recording medium and the thermal transfer material after applying heat. If it is relatively early, F, >F2, and if it is relatively slow, F,
<F2. By changing the color tone of the first ink layer and the second ink layer in this way, it is possible to change the color tone by changing the timing of peeling off the recording medium and the thermal transfer material.
A color record is obtained.

The thermal transfer material of the present invention has a first ink layer 3 as shown in FIG.
By providing the adhesive layer 3 having supercooling properties between the adhesive layer 3 and the support 2, the adhesive layer 3 remains in a molten state even at a relatively slow peeling time, and therefore breaks within the adhesive layer 3, causing the first ink 4
The recorded image becomes a dull image.

In addition, when only the second ink layer 5 is transferred, that is, when the thermal transfer material and the recording medium are peeled off relatively early, the second ink layer 5 is divided as shown in FIG. The result is an image without

In the thermal transfer material of the present invention, the adhesive layer having supercooling property, the first and second ink layers have a constant Fl as described above.
+F2, but more specifically, it is desirable that each layer satisfy the following physical property conditions.

When the recording medium and the thermal transfer material are to be separated relatively quickly after heat is applied, F,>F2 must be satisfied.

In this case, the second ink layer 5 and the adhesive layer 3 having supercooling properties
Since both are in a molten state, the above adhesive force relationship is related to the cohesive force of both layers. That is, the melt viscosity at 150° C. is preferably 1 to 1 O2 cp for the second ink layer, and 10"-10' cp for the adhesive layer having supercooling properties. If the difference in melt viscosity is small, the first ink and the second ink Therefore, the melt viscosity of the adhesive layer 3 must be higher than the melt viscosity of the second ink layer 5 at the same temperature immediately after heat application.

Furthermore, if the peeling is relatively slow, F, < F2 must be true. In this case, since the parts other than the adhesive layer 3 having supercooling properties are solidified, cohesive failure occurs within the adhesive layer 3 and transfer occurs. For this reason, the adhesive layer 3 is heated to a temperature above its melting point or softening point to melt or soften, and then is left at room temperature for a period of time (hereinafter referred to as "
(referred to as "supercooling time") is 0.5 to 100 seconds, and even 0.
It is preferable that it is 5 to 10 seconds. This supercooling time is 0
．． If it is less than 5 seconds, the transferability of the first ink layer 4 will decrease and the
If the time exceeds 0 seconds, the recorded image immediately after being transferred to the recording material will lack stability.

The present invention utilizes such a difference in cohesive force to separate the functions of the first ink layer and the second ink layer, and also utilizes the supercooling property of the adhesive layer 3 to separate the functions of the first ink layer and the second ink layer. However, in order to improve the functional separability and print quality of these ink layers, it is preferable to maintain the following physical properties.

The softening point of the adhesive layer with supercooling property is 100 to 180°C
, more preferably 120 to 150°C. If it is less than 1009C, the melt viscosity at 150°C will be less than 10" c p, making it difficult to obtain an appropriate cohesive force.
If it exceeds C, it will be disadvantageous in terms of effective use of energy.

Further, as the first ink layer 4 and the second ink layer 5, conventional heat-melting binders can be used as they are, but in order to improve the color separation of these ink layers, it is necessary to
Preferably, the cohesive force at 0° C. is greater than that of the second ink layer. Further, it is preferable that the first ink layer and the second ink layer are compatible with each other, and in order to satisfy this requirement, different materials such as resins as exemplified later are used for the first ink layer, and wax is used for the second ink layer. 100 parts of each binder preferably contains a small amount (at least 50 parts).

The softening point of the second ink layer is preferably 50 to 150°C, more preferably 60 to 120°C. If it is less than 506C, the storage stability of the thermal transfer material 1 will be deteriorated and the non-printing area of the recording medium will be stained, while if it exceeds 150C, a large amount of energy will be required to soften the ink layer.

The first ink layer preferably has a softening point of 150° C. or higher, and may have no softening point. Furthermore, even if the binder used in the first ink layer is in a molten state even at room temperature, a large amount of pigment or filler can be added to prevent it from becoming artificially softened.

Next, the structure of each part of the thermal transfer material I of the present invention will be explained in detail.

The support 2 of the thermal transfer material of the present invention has a thickness of 3 μm.
It is also possible to use a plastic film of polyester, aramid, nylon, polycarbonate, etc. with a thickness of about 12 μm, or a thin film of paper such as capacitor paper with a thickness of 3 μm or less.

In the thermal transfer material 1 of the present invention, it is desirable that the entire ink layer (or adhesive layer) on the support 2 has a thickness of 20 μm or less. Further, the thickness of the adhesive layer 3, the first ink layer 4, and the second ink layer 5 each having supercooling properties is 0.5 to 10 μm.
A range of m is preferred.

In addition, it is also effective to provide a layer for supplementing heat resistance on the back surface of the support 2 (the surface opposite to the surface on which the ink layer is formed).

Further, when performing a thermal transfer recording method using the thermal transfer material 1 of the present invention, in addition to a thermal head, commonly used heating means such as infrared rays and laser beams can be used as heating means. In addition, in the case of electrical heating, if necessary, a conductive layer made of a thin film of aluminum or the like is provided between the support 2 and the adhesive layer 3 having supercooling properties to serve as a return electrode, or an ink is used as a return electrode. It may be electrically conductive.

The first ink layer 4 constituting the thermal transfer layer on the support 2 is formed by dispersing a colorant of a first tone in a binder (this does not mean to exclude the state in which it is dissolved); No. 5 is formed by dispersing a coloring agent of a second tone in a binder. The adhesive layer 3 having supercooling properties is mainly composed of a binder, but may contain a colorant if necessary.

In the thermal transfer material 1 of the present invention, when it is desired to obtain the color tone of the first ink layer 4 and the color tone of the second ink layer 5, a dark color such as black is applied to the first ink layer 4 and a dark color such as black is applied to the second ink layer 5. It is best to use bright colors such as yellow.

Further, when it is desired to obtain a color tone of the first ink layer 4 and a color mixture of the color tone of the first ink layer 4 and the color tone of the second ink layer 5, for example, the first ink layer 4 is yellow and the second ink layer 5 is magenta. If you set the colors to , you will get magenta and red. In addition, by changing the pigment concentration or layer thickness ratio of each layer, various recordings of two different colors can be obtained.

Colorants include carbon black, nigrosine dye,
Lamp Black, Sudan Black SM, Alkali Blue, First Yellow G1-Benzidine Yellow, Pigment Niro, India First Orange, Irgazine Red, Paranitroaniline Red, Toluidine Yellow
Red, Varanitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR,
Pigment Orange R1 Linole Red 20, Lake Red C10-Damin FB, Rhodamine B Lake,
Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Prilliant Green B1 Phthalocyanine Green, Oil Yellow GG, Zapon First Niro CGG, Kayaset Y963, Kayaset YG, Sumiblast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumi Blast Orange G1 Orazole Brown B1 Zapon First Mechalet CG.

Eisensbiron Red BEH, Oil Pink OP1
Victoria Blue F4R, First Gen Blue 500
7. All known dyes and pigments such as Sudan Blue and Oil Peacock Blue (combine two or more types if necessary)
can be used. In addition, metal powders such as copper powder and aluminum powder, mineral powders such as mica, etc. can be used. Furthermore, as other additives, surfactants, plasticizers, mineral oils, vegetable oil fillers, etc. may be appropriately added to the ink layer or the adhesive layer.

The binders used in the first ink layer and the second ink layer include spermaceti wax, beeswax, lanolin, carnauba wax,
Natural waxes such as candelilla wax, montan wax, and ceresin wax, petroleum waxes such as paraffin wax and microcrystalline wax, oxidized waxes, ester waxes, low molecular weight polyethylene, synthetic waxes such as Huitscher Robust wax, lauric acid, myristic acid, etc. acids, higher resin acids such as palmitic acid, stearic acid, behenic acid, higher alcohols such as stearyl alcohol and behenic alcohol, esters such as sucrose fatty acid ester, fatty acid ester of sorbitan, amides such as oleylamide, etc. Wax; or polyolefin resin, polyamide resin, polyester resin, epoxy resin, polyurethane resin, polyacrylic resin, polyvinyl chloride resin, cellulose resin, polyvinyl alcohol resin, petroleum resin, phenol resin Resins, polystyrene resins, vinyl acetate resins, natural rubber, elastomers such as styrene-butadiene rubber, isoprene rubber, chloroprene rubber, resins such as polyisobutylene and polybutyne; etc. are used in combination of two or more as necessary. Ru.

The content of the coloring agent, that is, the coloring agent in the first ink layer and the second ink layer, is the same as that of the first ink layer. For each of the second ink layers, 1
A range of 90% to 90%, more preferably 2 to 80%.

On the other hand, as a supercooled thermofusible binder used in an adhesive layer having supercooling properties, the present applicant's previous application (Japanese Patent Application No. 1983)
In addition to the unsaturated polyester binder described in Japanese Patent Application No. 173984), known supercooling substances such as N-cyclohexyl-p- Toluenesulfonamide, N-ethyl-p-toluenesulfonamide, dicyclohexyl phthalate, benzotriazole,
A binder containing 20 to 900 parts of acetanilide or the like is also preferably used.

The above-mentioned thermofusible binders (used to include supercooled thermofusible binders) may be used in combination of two or more types as necessary, and so-called liquid rubbers such as polyisobutylene and polybutyne, Or plasticizer,
It is also possible to adjust the supercooling property, melt viscosity, adhesive force, degree of hydrophilicity-hydrophobicity, etc. by adding additives such as oil agents and surfactants.

Further, although the basic layer structure of the present invention is as shown in FIG. 1, a second adhesive layer 6 is provided between the first ink layer 4 and the second ink layer 5 as shown in FIG. By improving the color separation, or by providing the third adhesive layer 7 on the second ink layer 5 as shown in FIG. 5, it is possible to increase the adhesive force to the recording medium, and the transfer rate can be improved.

These second. As the third adhesive layer, the conventional heat-melting binder described above can be used.

In manufacturing the thermal transfer material of the present invention, a coating solution is prepared by mixing the materials constituting each of the layers described above with an organic solvent capable of dissolving the binder, such as methyl ethyl ketone, xylene, or tetrahydrofuran, and each layer is sequentially coated. All you have to do is work it out.

Moreover, after mixing the materials constituting each layer, they may be heated and melted to perform a so-called hot melt coating in the molten state.

Furthermore, the materials constituting each layer may be mixed and applied as an aqueous emulsion by adding a dispersant such as a surfactant. Furthermore, using these methods, it is also possible to coat each layer using a different method.

Next, a two-color printing method using the thermal transfer material of the present invention will be explained.

Specifically, an apparatus as shown in FIG. 6 is preferably used.

Referring to FIG. 6, the thermal transfer material l of the present invention is brought into pressure contact with the recording medium 9 by the thermal head 8 (so that the second ink layer faces the recording medium), and at the same time, from the thermal head 8 Heat is applied in a pattern to the thermal transfer material l. Immediately after this heat application, when the recording medium 9 and the thermal transfer material 1 are separated at the terminal end 8a of the thermal head 8, only the second ink layer is transferred to the recording medium 9 (because F, >F2). on the other hand,
1 by moving the peeling control member 10 in the direction of arrow A.
0a (dotted line), press the recording medium 9 and the thermal transfer material l in the same way as above, apply patterned heat with the thermal head 8, and then move the peeling control member 10 to the position (10a). When peeled at (F, <F
2) Both the first ink and second ink layers are transferred to the recording medium.

〔Effect of the invention〕

As described above, according to the present invention, by providing at least the adhesive layer, the first ink layer, and the second ink layer on the support, it is possible to transfer not only the second ink layer but also the first ink and the second ink layer. Even when both of the two ink layers are transferred, due to cohesive failure of the adhesive layer, the fractured surface becomes a rough surface, and the recorded image is always matte, easy to see, and beautiful.

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

1 boat L'' (Adhesive layer) (First ink layer) (Second ink layer) Each component of the above formulation is sufficiently dissolved and mixed or dispersed to form the adhesive layer, first ink layer, and second ink layer to a thickness of It was coated in order on a 4.5 μm polyethylene terephthalate film support (hereinafter referred to as PET), and each
After drying at a temperature of
A thermal transfer material (I) of rrr was obtained.

(Second adhesive layer) Carnauba wax aqueous dispersion (Second ink layer) Each component of the above formulation was thoroughly mixed, and the second adhesive layer and second ink layer were formed into the same adhesive layer and second ink layer as in Example 1. The adhesive layer, the first ink layer, the second ink layer, and the second ink layer are each coated in an amount of 1.0 g/rr? , 2.0g/i.

1.0g/po and 2. Og/rrr thermal transfer material (n
) was obtained.

By comparison, a thermal transfer material (III) similar to that of Example 2 was obtained except that the following adhesive layer was applied in an amount of 1.0 g/1rd instead of the adhesive layer having supercooling properties of Example 2.

(Adhesive Layer) Next, the above thermal transfer materials (1), (n), and (III) were mounted on a Type Star 6 manufactured by Canon (M), and printing was performed.

Referring to FIG. 6, as the thermal head 8, a ROHM ■ head with a distance of 350 μm from the center of the heat generating part to the end 8a of the thermal head is used, and a carriage 13 on which the thermal head 8 and the thermal transfer material 1 are mounted is used. Traveling speed 50m
It was moved in the direction of arrow B at m/sec. Therefore, when peeling off rapidly, the time from heat application to peeling was about 7 m5ec.

Further, a peeling control member IO for delaying peeling was installed at a position 5 mm (I!=5 mm) downstream in the transport direction of the thermal transfer material 1 from the terminal end 8a of the thermal head. Therefore, when peeling was performed with a delay, the time from heat application to peeling was about 100 m5ec. The position of the peeling control member 10 is j? =2mm to f=
Even when the distance was changed to 20 mm, there was almost no change in the printing results.

When the thermal transfer materials (1), (n), and (III) were used to print on plain paper as described above, the prints were blue when peeled off rapidly, and black when peeled off after a while. was obtained.

When thermal transfer material (1) was used, the blue print was a little lighter in blue than when thermal transfer material (n) was used, and some density unevenness was observed, as well as some black color. However, it was sufficiently good for practical use. Thermal transfer material (
1), (n) and (Ill) were all matte.

On the other hand, when the thermal transfer materials (I) and (IT) were used, the black printing was matte without gloss, and was in harmony with the blue printing, but when the thermal transfer material (ILL) was used, the black printing was matte. was shiny and unsightly compared to blue printing.

[Brief explanation of the drawing]

1 to 5 are schematic cross-sectional views of the thermal transfer material viewed in the thickness direction, and FIG. 1, FIG. 4, and FIG. 5 are examples of the layer structure of the thermal transfer material of the present invention. 2 and 3 are examples of the aspect of the thermal transfer material of the present invention during transfer, and FIG. 6 is an example of an aspect of the thermal transfer recording device used when performing two-color recording using the thermal transfer material of the present invention. shows.

Claims (1)

[Claims] An adhesive layer, a first ink layer, and a second ink layer having at least supercooling properties are provided on the support from the support side, and the supercooling time of the adhesive layer is in the range of 0.5 to 100 seconds. , and a melt viscosity of the adhesive layer at 150° C. is higher than a melt viscosity of the second ink layer.