JPH08164678A - Thermal transfer recording material - Google Patents

Abstract

PURPOSE: To provide a thermal transfer recording material which indicates good pigment dispersion and transfer performance, has heat resistance, and can form a printed image having good solvent resistance and scratch resistance. CONSTITUTION: In a thermal transfer recording material in which a heat melting ink layer comprising a vehicle and pigment is placed on a base material, 85wt.% or more of the vehicle is occupied by an epoxy resin, and the pigment has oil absorption of 80 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording material for forming an image having good heat resistance, solvent resistance and scratch resistance.

[0002]

2. Description of the Related Art Conventional thermal transfer recording materials are generally applied to a base material coated with a hot-melt ink containing a wax as a main component of a vehicle or a paper having a poor surface smoothness. In order to form an image of good quality or to form an image of good fastness, a heat-meltable ink containing a resin as a main component of a vehicle is applied.

In recent years, a thermal transfer recording material is used for printing a bar code or the like which is used for parts management in a manufacturing process in a manufacturing factory, product management, product management in the distribution field, article management in the field of use, and the like. Bar code printers and label printers are being used.

Some of the articles to which such a bar code is attached are exposed to a high temperature after the bar code is attached. For example, in the manufacturing process of printed wiring boards, 180 ℃
In a semiconductor inspection process, a heat treatment of about 250 ° C. is performed.

Further, in the case of bar codes used for product management in manufacturing factories, etc., there are many opportunities to come into contact with solvents, oils, etc., so good solvent resistance is required, and bar codes used in the distribution field etc. In this case, since there are many occasions of being subjected to a rubbing action, good scratch resistance is required.

Not only barcodes but also commercial printing fields such as outdoor advertisements, election posters, general posters, standing signs, stickers, catalogs, pamphlets, calendars, etc. In the packaging field, light packaging bags, foods, beverages, medicines, paints, etc. In the field of clothing, such as container labels and tying tapes, quality transfer labels, process control labels, product control labels, and other small-volume production of a wide variety of products have come to use thermal transfer printers. Properties, solvent resistance, and heat resistance are required.

However, none of the conventional thermal transfer recording materials can form an image having excellent transferability and satisfying all of heat resistance, solvent resistance and scratch resistance.

That is, a conventional thermal transfer recording material using a heat-meltable ink mainly composed of wax is
The transfer property is good, but when exposed to a high temperature of about 250 ° C., the image may be decomposed and the image may be unreadable, and the solvent resistance and scratch resistance are also insufficient. In addition, a resin mainly composed of a resin such as ethylene-vinyl acetate copolymer is relatively excellent in heat resistance, solvent resistance and scratch resistance, but has a high melt viscosity and a transfer property higher than that of a wax-based one. Inferior. Further, a thermal transfer recording material using a heat-meltable ink containing bisphenol A diglycidyl ether as a vehicle has been proposed (Japanese Patent Publication No. 60-59159).
However, this bisphenol A type epoxy resin has a poor dispersibility of a pigment such as carbon black, and therefore the transferability is poor and a clear image cannot be obtained. Poor transferability in the thermal transfer recording system is a fatal drawback.

In view of the foregoing, it is an object of the present invention to provide a mark having good transferability, heat resistance enough to withstand high temperatures up to about 280 ° C., and excellent solvent resistance and scratch resistance. An object of the present invention is to provide a thermal transfer recording material capable of forming an image.

[0010]

The present invention provides a thermal transfer recording material comprising a base material and a heat-meltable ink layer comprising a vehicle and a pigment, and 85% by weight of the vehicle.
The above is made of epoxy resin, and the pigment has an oil absorption of 80 or more (1st invention)
Regarding

The present invention further provides the above-mentioned first invention,
The present invention relates to a thermal transfer recording material (second invention), wherein the epoxy resin is bisphenol A diglycidyl ether and / or a bromide thereof.

[0012] The present invention further provides the first invention or the second invention.
In the invention, a wax layer is provided between the substrate and the heat-meltable ink layer, and the penetration of the wax layer is 1 or less (third invention).
Regarding

In the present invention, the oil absorption of the pigment is
Oil absorption of dibutyl phthalate per 100 g of pigment (m
l) is meant. The penetration is measured under the condition of 25 ° C. by the penetration measuring method described in JIS K2235.

[0014]

ACTION AND EXAMPLE As described above, bisphenol A
Diglycidyl ether generally has poor dispersibility in pigments such as carbon black, but in the present invention, the oil absorption of pigments such as carbon black is 80.
It has been unexpectedly found that the above-mentioned materials have good dispersibility in bisphenol A diglycidyl ether and / or its bromide.

Accordingly, the oil absorption of bisphenol A diglycidyl ether and / or its bromide has an oil absorption of 80.
The heat-meltable ink obtained by dispersing the above-mentioned pigments has the pigments uniformly dispersed therein, so that the transferability is good and a high-density clear image is provided.

In the case of an epoxy resin other than bisphenol A diglycidyl ether and / or its bromide, dispersibility is improved by using a pigment having an oil absorption of 80 or more, but bisphenol A diglycidyl ether and / or In the case of the bromide, the effect of improving dispersibility is particularly remarkable.

The present invention will be described in detail below.

The hot-melt ink layer in the first invention comprises a vehicle and a pigment, 85% by weight or more of the vehicle is an epoxy resin, and the pigment has an oil absorption of 80 or more. If the oil absorption of the pigment becomes too large, the fluidity of the ink coating liquid tends to deteriorate, and the coatability tends to deteriorate. Therefore, the oil absorption of the pigment is preferably about 330 or less.

Since the pigment is uniformly dispersed in the heat-meltable ink layer, the transferability is good, and a clear image having a high density can be obtained, and the obtained image is 85% by weight of the vehicle.
Since it is an epoxy resin as described above, it can withstand high temperatures up to about 280 ° C., has excellent solvent resistance to kerosene, gasoline, ethanol, carbon tetrachloride and the like, and has good scratch resistance.

If the content of the epoxy resin in the vehicle is lower than 85% by weight, the scratch resistance is particularly poor.

In the present invention, the pigment dispersibility improving effect is obtained when the total amount of bisphenol A diglycidyl ether and / or its bromide is 50% by weight or more, and substantially 100% by weight, relative to the total amount of the epoxy resin. Is played significantly.

The bisphenol A diglycidyl ether (hereinafter sometimes abbreviated as BPADGE) used in the present invention is one kind of bifunctional epoxy resin, and in the present invention, it has the formula (I):

[0023]

Embedded image

(In the formula, m is usually an integer of 0 to 13)
Those represented by are preferred. BPA used in the present invention
DGE also includes mixtures of different values of m.
As BPADGE, those having a softening temperature in the range of 60 to 140 ° C. are preferable.

The brominated bisphenol A diglycidyl ether used in the present invention (hereinafter, Br-BPAD)
GE may be abbreviated as, for example, the formula (I
I):

[0026]

Embedded image

(In the formula, n is usually an integer of 0 to 13,
p1, p2, p3, and p4 are each independently an integer of 1 or 2). In the formula (II), the bromine atom is usually bisphenol A.
Substituted in the meta position with respect to the methylene group of the skeleton. Br
-BPADGE preferably has a softening point of 60 to 140 ° C.

A typical example of Br-BPADGE is formula (III):

[0029]

Embedded image

(Wherein n is the same as the above formula (II)).

When a vehicle containing Br-BPADGE as a main component is used as the vehicle of the heat-meltable ink layer in the present invention, flame retardancy can be imparted to the ink layer, and it passes UL standard (UL-94V-O), for example. You can get things. Therefore, the thermal transfer recording material in which the heat-meltable ink layer containing Br-BPADGE is provided on the flame-retardant substrate can be safely used in a high temperature environment. Also Br-BPADG
In the case where the print image of the heat-meltable ink containing E is formed on the flame-retardant transfer material, the print image does not disappear even in a higher temperature environment or when exposed to a flame.

In the present invention alone or BPADG
Examples of other epoxy resins that can be used in combination with E and / or Br-BPADGE include the following.

(1) Glycidyl ether type bisphenol F diglycidyl ether, brominated bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, novolac polyglycidyl ether, cresol novolac polyglycidyl ether, glycerin triglycidyl ether, pentaerythritol di Examples thereof include glycidyl ether and tetraphenolethane tetraglycidyl ether.

(2) Glycidyl ether / ester type p-oxybenzoic acid glycidyl ether / ester and the like.

(3) Glycidyl ester type phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, dimer acid diglycidyl ester and the like.

(4) Glycidyl amine type glycidyl aniline, triglycidyl isocyanurate and the like.

(5) Linear aliphatic epoxy type Examples include epoxidized polybutadiene and epoxidized soybean oil.

(6) Alicyclic epoxy type 3,4-epoxy-6-methylcyclohexylmethylcarboxylate, 3,4-epoxycyclohexylmethylcarboxylate and the like.

The other epoxy resins may be used alone or in combination of two or more. Other epoxy resins having a softening temperature of 60 ° C or higher are preferable, but liquid epoxy resins can also be used as long as the softening temperature of the entire vehicle becomes 60 ° C or more when mixed with other epoxy resins. Is.

The vehicle may be blended with a heat-melting resin other than the epoxy resin as long as the object of the present invention is not impaired. Examples of such heat-meltable resin include ethylene-vinyl acetate copolymer resin, ethylene-alkyl (meth) acrylate copolymer resin, phenol resin,
Examples thereof include styrene-acrylic copolymer resin, polyester resin and polyamide resin. The other heat-meltable resin is preferably used in an amount of 15% or less, especially 5% or less of the total amount of the vehicle.

The vehicle preferably has a softening temperature in the range of 60 to 120 ° C. from the viewpoint of storage stability and transferability of the thermal transfer recording material.

The content of the vehicle in the hot-melt ink is preferably in the range of 40 to 95% from the viewpoint of transferability and the like.

The pigment used in the present invention has an oil absorption of 80 or more,
It is more than 110 in particular. If the oil absorption is less than the above range, epoxy resin, especially BPADGE
And / or poor dispersibility in Br-BPADGE.

Carbon black, azo pigments (insoluble azo, azo lake, condensed azo pigment), phthalocyanine pigments, nitro pigments, nitroso pigments, anthraquinone pigments, nigrosine pigments, as long as the oil absorption is in the above range. Various organic and inorganic pigments such as pigments, quinacridone pigments, perylene pigments, isoindolinone pigments, dioxazine pigments, titanium white, calcium carbonate and barium sulfate can be used. The content of the pigment in the ink layer is appropriately in the range of 5 to 60% by weight.

When a subtractive color mixture is used to form a multicolor or full-color image, yellow, magenta, and cyan pigments, and if necessary, black pigments are used.

Transparent pigments are preferably used as the yellow, magenta and cyan pigments. An opaque black pigment is usually used.

Examples of the yellow transparent pigment include naphthol yellow S, Hansa yellow 5G, Hansa yellow 3G, Hansa yellow G, Hansa yellow GR, Hansa yellow A, Hansa yellow RN, Hansa yellow R, benzidine yellow, benzidine yellow G, and benzidine yellow GR.
One or more organic pigments such as permanent yellow NCG and quinoline yellow lake can be used.

Examples of magenta transparent pigments include Permanent Red 4R, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Carmine FB, Resole Red, and Permanent Red F5.
One or more organic pigments such as R, Brilliant Carmine 6B, Pigment Scarlet 3B, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, and Quinacridone Red can be used.

As the transparent cyan pigment, for example, one or more organic pigments such as Victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue and fast sky blue can be used.

Here, the transparent pigment means a pigment which, when dispersed in a transparent vehicle, gives a transparently colored ink.

As the black pigment, for example, one or more inorganic pigments such as carbon black and organic pigments such as aniline black can be used.

The content of the pigment in each colored ink layer is usually about 5 to 60% by weight.

In addition to the above-mentioned components, a dispersant and the like can be appropriately blended in the heat-meltable ink layer in the present invention.

In the heat-fusible ink layer of the present invention, the vehicle component is dissolved in a solvent, and the pigment and other additives are further dissolved and dispersed to prepare a coating liquid. It can be formed by applying the composition onto a substrate and drying.

The coating amount of the heat-meltable ink layer in the present invention (in terms of solid content, the same applies hereinafter) is usually 0.02 to 5 g / m.
² , more preferably 0.5 to 3 g / m ² .

Examples of the base material include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film and polyarylate film, polycarbonate film, polyamide film, aramid film, polyether sulfone film, polysulfone film, polyphenylene sulfide. A film, a polyetheretherketone film, a polyetherimide film, a modified polyphenylene ether film, a polyacetal film, and other various plastic films generally used as a substrate film for an ink ribbon of this type can be used. Also, high-density thin paper such as condenser paper can be used. The thickness of the substrate is usually 1
The thickness is about 10 to 10 μm, and the range of 1 to 6 μm is preferable from the viewpoint of reducing thermal diffusion and improving resolution.

When the thermal transfer recording material of the present invention is used in a thermal transfer printer equipped with a thermal head, a silicone resin, a fluororesin, a nitrocellulose resin, or a resin thereof is provided on the back surface of the base material (the surface which is in sliding contact with the thermal head). It is desirable to provide a conventionally known stick-preventing layer made of various heat-resistant resins modified by, for example, silicone-modified urethane resin, silicone-modified acrylic resin, or a mixture of these heat-resistant resins with a lubricant. preferable.

In a preferred embodiment of the present invention, a wax layer having a penetration of 1 or less is provided between the base material and the hot-melt ink layer. In a printed image obtained by using the thermal transfer recording material having such a structure, the surface of the printed image is covered with a hard uncolored wax layer having a penetration of 1 or less, and the surface of the wax layer has a lubricating property and a protective effect. Thereby, scratch resistance is further improved. Furthermore, the solvent resistance to ethanol is further improved. If the penetration of the wax layer is greater than 1, the scratch resistance will deteriorate.

Examples of the wax include carnauba wax, polyethylene wax and the like, or a mixture of two or more thereof.

The wax layer can be formed by applying a solvent solution of wax, a solvent dispersion or an aqueous emulsion onto a substrate and drying. Further, it can be formed by a hot melt coating method.

The amount of the wax layer applied is usually 0.01.
To 2.0 g / m ² , more preferably 0.1 to 1.0 g / m ² .
m ² is suitable. If the coating amount of the wax layer is less than the above range, the desired effect tends to be difficult to be obtained, while if it is more than the above range, the transferability may be deteriorated.

The thermal transfer recording material of the present invention includes a thermal transfer recording material for forming a single color image and a color thermal transfer recording material for forming a multicolor or full color image by using subtractive color mixture. Be done.

The thermal transfer recording material for forming a monochromatic image is a monochromatic thermofusible ink layer provided on a substrate. The colors of the heat-meltable ink layer are black, red, blue,
Examples include green, yellow, magenta and cyan.

One embodiment of a color thermal transfer recording material for forming a multicolor or full color image is
A yellow heat-meltable ink layer, a magenta heat-meltable ink layer, a cyan heat-meltable ink layer, and if necessary, a black heat-meltable ink layer are arranged side by side on a single substrate. . There are various modes of arranging the ink layers of the respective colors, and the method is appropriately selected according to the type of printer.

FIG. 1 is a partial plan view showing an example of the thermal transfer recording material of the above embodiment. In FIG. 1, a yellow heat-meltable ink layer 2Y, a magenta heat-meltable ink layer 2M, and a cyan heat-meltable ink layer 2C are arranged side by side on a single substrate 1. The ink layers 2Y, 2M, and 2C each have a fixed size, and are arranged in the longitudinal direction of the base material 1 repeatedly in the fixed order as one repeating unit U. The order of arranging the three color ink layers in the repeating unit U is appropriately determined according to the transfer order of each color. A black ink layer may be added to the repeating unit U.

Another embodiment of a color thermal transfer recording material for forming a multicolor or full color image is 1
First, a yellow heat-meltable ink layer is provided on one substrate
Thermal transfer recording material, a second thermal transfer recording material having a magenta heat fusible ink layer provided on another substrate, and a third thermal transfer recording material having a cyan heat fusible ink layer provided on another substrate. It comprises a recording material and, if desired, a fourth set of thermal transfer recording materials with a black heat-meltable ink layer provided on another substrate.

When the thermal transfer recording material for color image formation is used, a multicolor or full-color image excellent in heat resistance, scratch resistance and solvent resistance can be obtained. Furthermore, since the heat-meltable ink layers of the respective colors in the present invention have good overlayability, a color image with good color reproducibility can be obtained.

If the wax layer is provided between the base material and the ink layer of each color, the good overlayability of the ink layer of each color tends to be impaired, so it is preferable not to provide the wax layer.

In order to form an image using the thermal transfer recording material of the present invention, the ink layer of the thermal transfer recording material is superposed on the transfer target, and imagewise thermal energy is applied to the ink layer. A thermal head is generally used as a heat source for giving heat energy, but any known one such as a laser beam, an infrared flash, or a heat pen can be used.

In the case where the transfer target has a three-dimensional shape that is not a sheet, and the surface thereof is a curved surface, thermal transfer by laser light is advantageous from the viewpoint of easy application of heat energy.

The formation of a multicolor or full-color image using the thermal transfer recording material for color image formation of the present invention is usually carried out by a thermal transfer printer into a separation color signal of a multicolor color image, that is, a yellow signal, a magenta signal and a cyan signal. Therefore, the yellow ink dot, the magenta ink dot, and the cyan ink dot are sequentially transferred in a predetermined order to form a yellow separated image, a magenta separated image, and a cyan separated image on the image receptor. it can. The transfer order of yellow ink dots, magenta ink dots, and cyan ink dots can be arbitrarily selected. In the case of a normal multicolor or full-color image, a three-color separated image is formed according to the three-color signal, but when there are only two color signals, a corresponding two-color separated image is formed. .

Thus, (A) a region where a color is developed by subtractive color mixing of at least two kinds of yellow, magenta and cyan, or (B) the region of (A) and yellow, magenta and cyan. It is possible to obtain a multicolor color image including a region formed by a combination with at least one type of monochrome region. Here, the red color is at the overlapping portion of the yellow ink dots and the magenta ink dots, the green color is at the overlapping portion of the yellow ink dots and the cyan ink dots, and the blue color is at the overlapping portion of the magenta ink dots and the cyan ink dots. , A black color is presented at the overlapping portion of the yellow ink dots, the magenta ink dots, and the cyan ink dots.

In the above description, the black color is obtained by superimposing the yellow ink dots, the magenta ink dots, and the cyan ink dots, but it is possible to obtain the black color only with the black ink dots without using the three color ink dots. You may

Note that the black ink dots may be superposed on at least one of the yellow ink dots, the magenta ink dots, and the cyan ink dots, or may be superposed on at least two of them so as to exhibit a black color.

Since the thermal transfer recording material of the present invention gives an image having excellent heat resistance as described above, it is preferably used for forming an image on a transfer-receiving member which is heat-treated at a temperature of 150 ° C. or higher. It If the temperature of the heat treatment to which the transferred material is subjected is too high, the vehicle component tends to decompose and the form as the printed image tends to disappear, so the temperature of the heat treatment to which the transferred material is subjected is about 280 ° C. or less. Is preferred.

When an image is formed by using the thermal transfer recording material of the present invention, the image may be directly formed on the target transferred material, but it is previously printed on the sheet-shaped transferred material (image receiving material). After forming an image, the image receptor may be attached to a target transfer target by an appropriate means such as a heat resistant adhesive.

As the sheet-shaped image receptor, various heat-resistant sheet-shaped materials can be used, but those disclosed in Japanese Patent Application No. 6-141996 filed previously by the present applicant are preferably used. . This is an image receptor in which a white pigment and an image receiving layer containing an organic binder as essential components are provided on one side of the substrate, and a heat resistant adhesive layer is provided on the other side,
The organic binder is a phenoxy resin or a phenoxy resin and a saturated polyester resin.
In addition, sheet-shaped materials of heat-resistant resin such as polyimide, cloth-shaped materials of glass fiber or ceramic fiber, those coated or impregnated with heat-resistant resin, sheet-shaped materials of glass or ceramics, sheet-shaped materials of metal, etc. Can be given.

The heat resistance, solvent resistance, and scratch resistance of a printed image formed on a transfer target using the thermal transfer recording material of the present invention are significantly improved by heat treatment.

The heat treatment can be carried out by heating the printed image in an atmosphere of 150 to 250 ° C. for 15 to 60 minutes. It is presumed that such heat treatment causes the epoxy resin to crosslink, which improves the fastness.

In the case of an image printed on an article such as a printed wiring board or a semiconductor, which is subjected to a heat treatment similar to the heat treatment in the subsequent step, it is not necessary to perform the heat treatment.

Since the thermal transfer recording material of the present invention gives an image having excellent heat resistance and solvent resistance, the material to be transferred has a temperature of about 150 to 280 ° C. in a manufacturing process such as a printed wiring board and an inspection process such as a semiconductor. It is particularly preferably used for forming an image on an object which is subjected to a heat treatment at a high temperature.

Next, the present invention will be described with reference to examples.

Examples 1 to 6 and Comparative Examples 1 to 3 A polyethylene terephthalate film having a thickness of 5 μm was coated with a stick-prevention layer made of a silicone resin at a coating amount of 0.25 g / m ² on one side, and Table 1 was formed on the opposite side. The ink coating liquid shown in 1 is applied and dried, and the applied amount is 2 g / m ^2.
A heat-meltable ink layer was formed to obtain a thermal transfer recording material.

[0084]

[Table 1]

The heat resistance of each ink was evaluated.
Further, printing was performed using each of the thermal transfer recording materials, and the obtained printed images were evaluated for solvent resistance, scratch resistance and transferability. Printing was performed using a thermal transfer bar code printer (B-30 manufactured by Tech Co., Ltd.) under the following conditions. Applied energy: 25.8 mJ / mm ² Printing speed: 2 inches / second Platen pressure: Strong Printing pattern: Checker flag pattern The results are shown in Table 2.

[Heat resistance] About 10 mg of each ink after drying
After being weighed with an electronic balance and heat-treated at 250 ° C. for 1 hour in a heat oven, the weight was measured, and the ink residual ratio (%) represented by the following formula was determined to evaluate heat resistance. Residual rate is 80%
Above is no practical problem.

Ink residue rate (%) = (weight after heat treatment / weight before heat treatment) × 100 [Solvent resistance] An adhesive layer was formed on the aluminum vapor deposition side of an aluminum vapor deposition polyethylene terephthalate film as an image receptor. An image (checkered flag pattern) formed on the surface of a polyethylene terephthalate film was rubbed with a cotton swab impregnated with each solvent shown in Table 2 10 times, and evaluated according to the following criteria.

Evaluation Criteria A: No printed image can be obtained. B: Almost no image can be taken. C: A little impression can be taken. D: A good impression can be obtained. The evaluation values A and B are within the practical range.

[Scratch resistance] As the image receptor, the same one as in the solvent resistance test was used, and the obtained image (checkered flag pattern) was subjected to the following scratch resistance test and evaluated according to the following criteria. Test conditions Tester: Love tester manufactured by Yasuda Seiki Seisakusho Ltd. Friction material: Sand eraser Pressure: 250 g / cm ² Number of reciprocations: 10 times Evaluation criteria A: No change in printed image. B: There is almost no change in the printed image. C: A very slight impression can be taken. D: A good impression can be obtained. E: The printed image disappears and disappears. The evaluation values A, B and C are within the practical range.

[Transferability] As an image receptor, a silicone resin pressure-sensitive adhesive layer was formed on one side of a polyimide film having a thickness of 76 μm, and a white coating layer (coating amount 28 g / m ² ) of the following composition was formed on the opposite side. The formed product was used (hereinafter, this image receptor is referred to as image receptor A).

Component Weight part Saturated polyester resin 5 Phenoxy resin 11 Titanium oxide 29 Reflects the reflection optical density (OD value) of the solid print portion of the printed image (checkered flag pattern) obtained on the white coating layer of the image receptor A Concentration measuring device (Macbeth RD914)
And transferability was evaluated. If the OD value is 0.8 or more, there is no practical problem.

[0092]

[Table 2]

Further, using the thermal transfer recording materials of Examples 1 to 6, an image was formed on the white coating layer of the image receptor A under the same printing conditions as described above with the same bar code printer as described above, and then the image was printed. The image receptor A on which the image was formed was placed in a drying oven MODEL DX-58 manufactured by Yamato Scientific Co., Ltd.
The image subjected to the heat treatment at 200 ° C. for 60 minutes and subjected to the heat treatment in this way was evaluated for solvent resistance, scratch resistance and transferability in the same manner as described above. The results are shown in Table 3.

[0094]

[Table 3]

Examples 7 and 8 and Comparative Example 4 The surface of the polyethylene terephthalate film (the side opposite to the stick preventing layer) was coated with the wax coating liquid shown in Table 4 and dried to give a coating amount of 0.4 g / m ^2. The wax layer is formed, and then the ink coating liquid having the same formulation as in Example 1 is applied onto the wax layer and dried to form a heat-meltable ink layer having a coating amount of 2 g / m ² to perform thermal transfer recording. Got the material. Using each of the obtained thermal transfer recording materials, heat resistance, solvent resistance, scratch resistance and transferability were evaluated for the printed images that were not subjected to heat treatment by the same method as in Examples 1 to 6. The results are shown in Table 4.

[0096]

[Table 4]

As is clear from Table 4, in Examples 7 and 8 in which the wax layer having a penetration of 1 or less was provided, scratch resistance and ethanol resistance were further improved as compared with Example 1. On the other hand, in Comparative Example 4, since the wax layer is provided, the scratch resistance and the solvent resistance are rather deteriorated. It is presumed that this is because the penetration of the wax layer exceeded 1 (penetration 12), so that the wax plasticized the epoxy resin ink by heat during thermal transfer.

[0098]

According to the first aspect of the invention, in a thermal transfer recording material comprising a base material and a heat-meltable ink layer comprising a vehicle and a pigment, 85% by weight or more of the vehicle is an epoxy resin, When the pigment has an oil absorption of 80 or more, the pigment dispersibility is good and the transferability is excellent, so that a high-density clear printed image can be obtained, and the obtained printed image can be heated to a high temperature of up to about 280 ° C. Good resistance to solvents, such as resistance to kerosene, resistance to gasoline, resistance to ethanol, and resistance to carbon tetrachloride.

According to a second invention, in the first invention, the epoxy resin is BPADGE and / or B.
By virtue of being r-BPADGA, the effect of improving the dispersibility of the pigment is particularly remarkable.

According to a third invention, in the first or second invention, a wax layer having a penetration of 1 or less is provided between the base material and the hot-melt ink layer. , Scratch resistance and ethanol resistance are further improved.

[Brief description of drawings]

FIG. 1 is a partial plan view showing an example of an arrangement of ink layers of respective colors in an embodiment of a thermal transfer recording material of the present invention.

[Explanation of symbols]

 1 Base Material 2Y Yellow Ink Layer 2M Magenta Ink Layer 2C Cyan Ink Layer

Claims (3)

[Claims] 1. A thermal transfer recording material comprising a base material and a heat-meltable ink layer comprising a vehicle and a pigment, wherein 85% by weight or more of the vehicle is made of an epoxy resin, and the pigment has an oil absorption of 80 or more. A thermal transfer recording material characterized by: 2. The thermal transfer recording material according to claim 1, wherein the epoxy resin is bisphenol A diglycidyl ether and / or a bromide thereof. 3. The thermal transfer according to claim 1, wherein a wax layer is provided between the substrate and the heat-meltable ink layer, and the penetration of the wax layer is 1 or less. Recording material.