JP3056420B2 - Thermal transfer recording medium - Google Patents

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 medium for forming an image by transferring a thermal transfer ink layer on a support to a medium to be transferred, using a heat source such as a thermal head printer. The transfer image can be transferred well to the transfer medium, and the transferred image is excellent in mechanical abrasion resistance and the like. The present invention relates to a heat-sensitive transfer recording medium having excellent color reproducibility so that the light transmittance of an ink layer is good and a clean layer structure can be formed.

[0002]

2. Description of the Related Art A thermal transfer recording system using a thermal head has been used for various purposes such as a label printer, a ticket issuing machine, and a word processor.
The environment in which printed materials are used as these applications expand,
It has been used in a more severe environment than the environment used conventionally.

[0003] Further, as the printed material is used in a more severe environment, the medium to be transferred is also changed from conventional paper and the like.
Its use in plastic films, which are less environmentally dependent, is expanding. If the medium to be transferred becomes special, conventional ribbons with a thermal transfer ink composition centered on wax will not be able to perform good transfer, or will transfer, but the printed matter will be removed by simple rubbing. However, problems such as not satisfying the mechanical abrasion resistance have arisen.

[0004] In particular, in the fields of printed matter, posters, signboards, and the like, which require a high-class feel, there are severe restrictions on the color reproducibility and color unevenness of the transferred matter. Did not.

Further, in the conventional thermal transfer ribbon, when the color is expressed by repeating the transfer onto the same transfer-receiving medium and overlapping the thermal transfer ink layers, the thermal transfer ink has a low softening point and a low viscosity at the time of melting. Therefore, when performing overprinting twice or more, due to the heat of the thermal head at the time of overprinting, the composition of the previously printed transfer ink layer is melted, and color unevenness due to ink mixing, Ink repelling occurs, and if the ink becomes more severe, problems such as the occurrence of untransferable objects have occurred.

As a countermeasure, all the inks to be transferred a plurality of times are immersed in the paper as the medium to be transferred to create a mixed state of the inks, and color expression is performed. Fine mechanical, such as lowering the transfer energy on the printer side according to the overlap and maintaining good transferability
Electric control was required. In addition, the number of transfer
Some attempts have been made to change the softening temperature of the ink layer to be transferred in accordance with the order to achieve both transferability and color reproducibility.

However, even if these measures are taken, it is good when the medium to be transferred is made of a material such as paper, but the absorption of thermal transfer ink such as a plastic base material during transfer is low. The material had drawbacks such as a poor effect.

[0008]

As described above, the environment in which a printed material obtained by thermal transfer printing using a thermal head is used in an environment that is more severe than the environment used conventionally. I have. For example, use under severe room temperature or use in an environment where printed matter is mechanically scratched.

Along with this, a special durable medium is used for the medium to be transferred as described above, and good transfer to a plastic film or the like, or only a printed matter is necessary. When obtaining a durable printed matter, and when expressing color by repeating the transfer on the same transfer medium and overlaying the thermal transfer ink layer, color unevenness due to ink mixing and ink repelling may occur However, problems such as poor fixability due to the overlapping of the inks have arisen.

That is, good thermal transfer can be performed on a transfer-receiving medium such as a durable plastic film, and the printed matter can be obtained while obtaining a printed matter having sufficient mechanical abrasion resistance. When color is expressed by repeatedly transferring the thermal transfer ink layer on the medium to express color, it is necessary to obtain a print that does not cause color unevenness due to ink mixing or ink repelling, and sufficient rub resistance even when ink is overlaid There is a major issue in obtaining a material that satisfies all of the requirements for having the property, and in order to achieve that issue, the thermal transfer ink layer component of the thermal transfer recording medium, the so-called ink ribbon, is considered to be the key to a major solution. Was. Although research on the composition of the transfer ink component has been conventionally performed, no proposal has been made yet to reach the level required for the present invention. The aim of the invention is to propose exactly this solution.

[0011]

According to the present invention, there is provided a thermal transfer recording medium comprising a support and a thermal transfer ink layer comprising at least a colorant and a thermoplastic resin provided on a support. The present invention has been completed by using a material having a specific viscoelastic property. That is, the present invention provides: “1. A thermal transfer recording medium in which a thermal transfer ink layer comprising at least a colorant and a thermoplastic resin is provided on a support,
The above thermoplastic resin is in the entire temperature range of 100 to 150 ° C.
In a softened state and at a temperature in the range of 100 to 150 ° C.
A multicolor mark is printed by superimposing a plurality of thermal transfer ink layers of a plurality of colors characterized by exhibiting the following behaviors (a) and (b) in a viscoelasticity measurement at a frequency of 1 Hz in a linear viscoelastic region in the entire region.
A thermal transfer recording medium that performs characters . (A) tan δ is 1.7 or more (b) Complex dynamic viscosity is 10 to 20000 Pa · S 2. The thermal transfer recording medium according to claim 1, wherein the colorant comprises at least a pigment, and the pigment comprises an organic pigment. 3. (1) The colorant comprises at least an inorganic pigment, and the ratio of the refractive index Np of the inorganic pigment to the refractive index Nr of the vehicle is in the range of Np / Nr = 1.12 to 1.00. 2. The thermal transfer recording medium according to 1. ".

According to the above arrangement, when the thermal transfer recording medium is used to thermally transfer a plurality of colors onto a transfer-receiving medium such as a plastic substrate by using a thermal printer or the like, the transfer ink layers are respectively formed. In order to form a beautiful layered structure,
Good overprinting can be performed, and the printed image can be maintained in a good printing state without falling off or being damaged even by strong mechanical abrasion.

[0013] The thermoplastic resin of the present invention has a content of 100 to 150.
In a softened state within a temperature range of 100 ° C.
Frequency 1H in linear viscoelastic region in temperature range of 0 ° C
It has physical properties such that tan δ is 1.7 or more and complex dynamic viscosity is 10 to 20,000 Pa · S in viscoelasticity measurement of z.

Therefore, in the thermal transfer recording medium of the present invention using the above-mentioned thermoplastic resin, when the thermal transfer ink layers are superposed and transferred, the ink composition has a completely layered structure, and the same plastic material is used as the transfer-receiving medium. Even in the case of using a base material to repeat transfer and superimpose the thermal transfer ink layer to express a color, it is possible to obtain a print in which color unevenness due to ink mixing and ink repelling do not occur.

[0015] The thermal transfer recording medium of the present invention is preferably 100 to 15
It is necessary to include a thermoplastic resin in a softened state over the entire temperature range of 0 ° C. In a part or the whole of this temperature range, a material having a high softening point that does not take a softened state, that is, maintains a solid state at a low temperature side during heating, can be sufficiently supplied with heat energy from a printer during transfer. Insufficiency of transfer occurs without softening to the extent that thermal transfer is possible, and the amount of energy during transfer is insufficient, so that the adhesion between the printed matter and the print-receiving medium is deteriorated, and the print falls off due to light mechanical abrasion.

Further, in a viscoelasticity measurement at a frequency of 1 Hz in a linear viscoelasticity range in a temperature range of 100 to 150 ° C., t
an δ is 1.7 or more, complex dynamic viscosity is 10 to 2000
It is important that the thermal transfer ink composition contains 0 Pa · S thermoplastic resin.

Here, in the viscoelasticity measurement by a rheometer vibration method, when a sine wave force is applied to a sample, for example, the linear viscoelasticity region is defined as a torque, a frequency, and a gap between measurement geometry. And the like, where the conditions are appropriately set and the detected phase shift is obtained as a stable continuous sine wave. Further, the value of the complex dynamic viscosity obtained here indicates a value relatively close to the value of the viscosity obtained by a general rotation measurement method.

In the present invention, the frequency given to the measurement is 1
Hz is used as a representative. The reason is that it is considered that an appropriate frequency includes 1 Hz when an area similar to the behavior at the time of actual thermal transfer is assumed.

The tan δ in the viscoelasticity measurement is obtained by dividing the value of the loss elastic modulus by the value of the storage elastic modulus. If tan δ is large, the physical properties of the sample are said to have a large viscous component, and tan δ is small. If so, it means that the elastic component is large.

In the present invention, it is essential that the ink composition contains a thermoplastic resin having a tan δ of 1.7 or more, that is, a relatively large viscous response. Tan during heat softening
The ink composition containing a thermoplastic resin having a physical property of δ of 1.7 or more can be transferred onto a transfer medium, such as a plastic film, which has conventionally been considered difficult to transfer, or when the transfer energy is somewhat insufficient. Even if the transfer is repeated and the thermal transfer ink layer is superimposed on the same transfer medium to express the color, the transfer ink layers each have a beautiful layered structure, without causing ink repelling, etc. In addition, it is possible to obtain a print having good scratch resistance of the overprinted product.

Conversely, if tan δ is less than 1.7, the elastic response becomes too strong, and it is not possible to obtain sufficient fluidity for good transfer at the time of transfer, so that poor transfer tends to occur. Increase. Further, even if the transfer can be performed, a problem arises because the transfer medium that can transfer well and the width of the printing energy are limited. tan δ
Is more preferably three or more.

Further, the thermoplastic resin used in the present invention comprises:
Further, the complex dynamic viscosity is required to be 10 to 20000 Pa · S in viscoelasticity measurement in a temperature range of 100 ° C to 150 ° C. When it is within this range, the transfer ink layer forms a clean layered structure even when directly transferred onto the transfer-receiving medium, and not only good transferability can be obtained, but also the transfer is repeated, and the thermal transfer ink layer is superimposed on the transfer ink layer. In the case of expressing, again, since each can form a clean layered structure,
Due to the heat of the thermal head at the time of overprinting, the composition of the previously printed transfer ink layer is melted, and color unevenness of ink mixing and ink repelling do not occur, and overprinting is performed. Multicolor printing with good abrasion resistance can be performed. The complex dynamic viscosity is 20-
More preferably, it is 5000 Pa · S.

Conversely, if the ratio is below this range, the fluidity at the time of heating and melting becomes too large and the thermal transfer ink layer after transfer cannot form a clean layered structure due to the transfer force applied at the time of transfer. Also, color unevenness occurs, which is not preferable. Furthermore, even in the case where the color is expressed by overlapping the thermal transfer ink layers, since the ink layer existing at the place to be transferred does not form a clean layered structure, irregularities are generated, and good thermal transfer is formed thereon. Is difficult to do. In addition, the composition of the previously printed transfer ink layer flows due to the amount of heat of the thermal head at the time of overprinting, causing color unevenness due to ink mixing, ink repelling, or overprinting. Subsequent abrasion resistance also tends to weaken, which is not preferable.

Above this range, the fluidity of the ink composition required for thermal transfer at the time of heating and melting cannot be obtained, and the tendency of poor transfer increases. Further, even if the transfer can be performed, there is a problem that a transfer medium that can transfer satisfactorily, a large print energy is required, and the like tend to cause a problem, which is not preferable.

In the present invention, the thermal transfer ink composition is constituted by using a thermoplastic resin having the above-mentioned physical properties, but other resins and various additives are added within a range not affecting the performance of the thermoplastic resin. You can also. Further, in order to form a high-performance thermal transfer ink layer, it is necessary to consider other components.

The thermal transfer ink layer of the present invention comprises at least a colorant and a thermoplastic resin. The coloring agent is preferable because the pigment has good light resistance when printed matter is used in an environment where the pigment is irradiated with ultraviolet rays such as outdoor exposure, and the thermal transfer ink layer itself has good mechanical strength. Pigments used include: carbon black, ultramarine, chrome yellow, cadmium yellow, Hansa yellow, disazo yellow, permanent red,
One or more pigments such as alizarin lake, quinacridone red, benzimidazolone red, victoria blue lake, phthalocyanine blue, phthalocyanine green, and dioxazine violet can be used.

In the thermal transfer recording medium of the present invention, if the thermal transfer ink layer to be transferred has good light transmittance, it is possible to obtain a printed matter having very excellent color expression at the overlapping portion of the transferred matter. Can be.

If the pigment is an organic pigment, its light transmittance is good. Therefore, even when the transfer is repeated and the thermal transfer ink layer is overlaid to express the color, the color tone of each layer is accurately expressed. In the overlapping portion, the color tone of each ink layer is uniformly and accurately obtained by the subtractive color mixture method, so that various chromatic colors can be expressed.

Further, when the pigment is an inorganic pigment, some pigments have poor light transmittance. When such a pigment is used, it is not easy to perform good overlapping multicolor printing. When an inorganic pigment is used as the pigment, it is preferable to use a combination of a pigment and a vehicle in which the ratio of the refractive index Np of the inorganic pigment to the refractive index Nr of the vehicle is in the range of Np / Nr = 1.12 to 1.00. Multicolor printing can be performed.

If the difference between the refractive indices of the two is larger than this range, the light transmittance deteriorates, that is, the concealing property of the thermal transfer ink layer becomes too large. When expressing, the ink layer outside the overlapped portion conceals the color tone of the previously transferred ink layer, making it impossible to accurately express the color of the previously transferred ink layer. It is not preferable because color mixing by the method cannot be obtained and a desired multicolor cannot be expressed.

When printing is performed by using the thermal transfer recording medium of the present invention in a superimposed manner, different components can be used for each of the plurality of thermal transfer ink layers to be used. It is also possible. In terms of thermal sensitivity control and coating, it is preferable that the ink of each layer is composed of the same components.

The thermoplastic resin used in the present invention includes:
Examples include a vinyl chloride resin, a polyamide resin, a polyvinyl alcohol resin, an acrylic resin, a polyester resin, an ethylene-methacrylic acid-acrylic acid copolymer, an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and a polystyrene-polyisoprene copolymer.

As the wax to be added, paraffin wax, candelilla wax, microcrystalline wax, polyethylene wax, beeswax, carnauba wax, gay wax, mocro, nuka wax, montan wax, ozokerite, ceresin, ester wax, Fischer-Trops wax, etc. And higher fatty acid waxes such as myristic acid, palmitic acid, stearic acid, furomenic acid, behenic acid, lauric acid and margaric acid; and amide waxes such as stearinamide and oleinamide.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION The thermal transfer recording medium of the present invention will be specifically described below.

As the support of the thermal transfer recording medium, various types of conventionally known plastic films can be used. The thermal transfer recording medium of the present invention has a heat-resistant lubricating layer on the back side of 2.5 to 6.0 μm. A degree of polyester film can be used.

The thermal transfer recording medium of the present invention is provided on a support.
Although it is configured by providing the thermal transfer ink layer,
There are no particular restrictions on the ink layer production method, and the ink layer is dispersed and dissolved in an aqueous or oil-based solvent to prepare a coating solution, which is required by a coating method such as a gravure coater, a wire bar coater, and an air knife coater. And a thermal transfer recording medium can be obtained.

When a thermal transfer ink layer is provided on a support, a single-color thermal transfer ink may be applied to the entire surface of the support to form a monocolor ribbon. May be sequentially provided in a block shape.

When printing a plurality of colors by using a plurality of thermal transfer recording media of the present invention, printing is performed by the following operation. When using a monocolor ribbon coated with a single color thermal transfer ink on the entire surface of the support, when printing with one thermal head, print with the first ribbon, then change the ribbon, The printed medium to be transferred is pulled back, and an operation for printing with the second ribbon is performed. When printing three or more colors, the same operation is performed in order, and multicolor thermal transfer recording can be performed.

When a ribbon in which transfer ink layers of a plurality of colors are sequentially provided in a block on one support is used, a special printer is required. It can be performed.

The thermal transfer ink layer of the present invention further contains additives in order to further improve various properties such as print abrasion resistance, ribbon running property and ribbon preservability, as long as the basic performance of the present invention is not reduced. May be. The compounding amount varies depending on the type of the additive, but is preferably 20% by weight or less based on the entire thermal transfer ink.

The coating thickness of the thermal transfer ink layer is 1.0 to 3.0.
About μm is preferable for good color expression including overprinting.

In the thermal transfer recording medium of the present invention, it is essential to provide a thermal transfer ink layer on a support, but other methods such as providing a functional layer such as a release layer between the support and the thermal transfer ink layer are also required. A layer may be provided.

[0043]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples. In the examples and comparative examples, all “parts” are by weight unless otherwise specified.

Example 1 A heat-resistant lubricating layer was formed on one side of a 4.5 μm-thick polyester film to provide a support, and a heat-transfer ink layer component having the following constitution was applied on the opposite side of the heat-resistant lubricating layer of the support. It was prepared so as to have a solid content of 30% in a solvent of toluene / methyl ethyl ketone (5.5 ratio), and was coated with a gravure coater to a coating thickness of 2.0%.
The coating was dried to a thickness of μm and dried to produce a black thermal transfer ink layer. (Components of thermal transfer ink layer) Polyester resin (Note 1) 75 parts Carbon black 20 parts Dispersant 5 parts (Note 1) Measurement value in viscoelasticity measurement at a glass transition point of 55 ° C. and a molecular weight of 5000 to 100 to 150 ° C. tan δ = 3.00 ５７57.0 complex dynamic viscosity = 95〜13400 Pa · S

Example 2 In the same manner as in Example 1, a thermal transfer ink layer having the following constitution was formed on a support to form a cyan thermal transfer ink layer, and a thermal transfer recording medium was obtained. (Components of thermal transfer ink layer) Polyester resin (Note 1) 60 parts Polyethylene wax (Note 2) 15 parts Phthalocyanine blue (organic pigment) 20 parts Dispersant 5 parts (Note 2) Polyethylene oxide wax having a melting point of 110 ° C.

Example 3 In the same manner as in Example 1, a thermal transfer ink layer component having the following constitution was formed on a support to form a magenta thermal transfer ink layer, and a thermal transfer recording medium was obtained. (Thermal transfer ink layer components) PVC / vinyl acetate / hydroxy acrylate resin (Note 3) 60 parts Polyethylene wax (Note 2) 15 parts Quinacridone red (organic pigment) 8 parts Benzimidazolone red (organic pigment) 12 parts Dispersant 5 parts (Note 3) Measurement value in viscoelasticity measurement at a glass transition point of 53 ° C. and a molecular weight of 5500 at 100 to 150 ° C. tan δ = 3.2 to 19.0 Complex dynamic viscosity = 37 to 3800 Pa · S

Example 4 In the same manner as in Example 1, a thermal transfer ink layer having the following constitution was formed on a support to prepare a yellow thermal transfer ink layer, and a thermal transfer recording medium was obtained. (Thermal transfer ink layer component) Polyester resin (Note 1) 60 parts Polyethylene wax (Note 2) 15 parts Disazo yellow (organic pigment) 20 parts Dispersant 5 parts

Example 5 In the same manner as in Example 1, a thermal transfer ink layer component having the following constitution was formed on a support to form a blue thermal transfer ink layer, and a thermal transfer recording medium was obtained. (Thermal transfer ink layer components) PVC / vinyl acetate / hydroxyacrylate resin (Note 3) 65 parts Polyethylene wax (Note 2) 10 parts Ultramarine blue (Note 4) 20 parts Dispersant 5 parts (Note 4) Inorganic pigment, refractive index (Np ) = 1.56 Refractive index (Nr) of vehicle = 1.53 Np / Nr = 1.02

Example 6 In the same manner as in Example 1, a thermal transfer ink layer having the following constitution was formed on a support to prepare a purple thermal transfer ink layer, and a thermal transfer recording medium was obtained. (Thermal transfer ink layer components) PVC / vinyl acetate / hydroxy acrylate resin (Note 3) 55 parts Polyethylene wax (Note 2) 10 parts Dioxazine violet (organic pigment) 20 parts Extender pigment (Note 5) 10 parts Dispersant 5 parts ( Note 5) Calcium carbonate powder (inorganic pigment), refractive index (Np) = 1.60 Refractive index (Nr) of vehicle = 1.53 Np / Nr = 1.05

Comparative Example 1 In the same manner as in Example 1, a thermal transfer ink layer having the following constitution was formed on a support to prepare a black thermal transfer ink layer, and a thermal transfer recording medium was obtained. PVC / vinyl acetate / vinyl alcohol copolymer (Note 6) 60 parts Polyethylene wax (Note 2) 15 parts Carbon black 20 parts Dispersant 5 parts (Note 6) Viscosity with glass transition point 70 ° C, molecular weight 20,000 100-150 ° C Measured value in elasticity measurement tan δ = 0.26 to 1.4 Complex dynamic viscosity = 3180 to 21800 Pa · S

Comparative Example 2 In the same manner as in Example 1, a thermal transfer ink layer component having the following constitution was formed on a support to prepare a blue thermal transfer ink layer, and a thermal transfer recording medium was obtained. PVC / vinyl acetate / hydroxy acrylate copolymer (Note 7) 60 parts Polyethylene wax (Note 2) 15 parts Phthalocyanine blue (organic pigment) 20 parts Dispersant 5 parts (Note 7) Glass transition point 70 ° C, molecular weight 20,000 100- Measured value in viscoelasticity measurement at 150 ° C. tan δ = 0.53 to 8.1 Complex dynamic viscosity = 430 to 36500 Pa · S

Comparative Example 3 In the same manner as in Example 1, a thermal transfer ink layer component having the following constitution was formed on a support to prepare a black thermal transfer ink layer, and a thermal transfer recording medium was obtained. Terpene resin (Note 8) 50 parts Ethylene / vinyl acetate copolymer (Note 9) 15 parts Polyethylene wax (Note 2) 10 parts Carbon black 20 parts Dispersant 5 parts (Note 8) Glass transition point 28 ° C, molecular weight 630 100 Measured value in viscoelasticity measurement at １５０150 ° C. tan δ = 11.4 to 57.2 Complex dynamic viscosity = 0.8 to 20 Pa · S (Note 9) Glass transition point −31 ° C., molecular weight 14000 100 to 150 ° C. Measurement value in viscoelasticity measurement tan δ = 3.1 to 6.8 Complex dynamic viscosity = 50 to 210 Pa · S

Example 7 The cyan, magenta, and yellow thermal transfer inks described in Examples 2, 3, and 4 were sequentially applied in the form of blocks using a gravure coater on the same support as in Example. Thus, a three-color thermal transfer recording medium was obtained.

The thus-prepared thermal transfer recording medium was mounted on a thermal transfer printer, and a transfer medium such as a white polyester label, a vinyl chloride label, a Yupo label, a peach coat label, a silver name label, etc. was used.
Printing including random overprinting on each thermal transfer recording medium was performed under printing conditions of .about.0.4 mj / dot and 2 inch / min to obtain a printed material. Table 1 shows the printing results.

Further, the thermal transfer recording medium of Example 2 was mounted on a thermal transfer printer, and 8 do
t / mm, 0.2-0.4 mj / dot, 2 inch /
After printing under the printing conditions of min, the print was replaced with the thermal transfer recording medium of Example 3 and the thermal transfer ink of Example 3 was overprinted on the same label to obtain a multicolor printed matter.

Each of the thermal transfer recording media of Examples 2, 3 and 4 was mounted on a multi-head thermal transfer printer having three print heads, and 8 dots / mm, 0.2 to 0.4 mj on a white polyester label. / Dot, 2i
Under the printing conditions of nch / min, printing was performed by superposing the respective ink layers on the same label to obtain a multicolor printed matter.

Further, the thermal transfer recording medium of Example 7 was mounted on a thermal transfer printer for multicolor printing, and 8 dots / mm, 0.2 to 0.4 mj / do was applied to a white polyester label.
After the transfer of the ink layer of the cyan block under the printing conditions of t, 2 inch / min, the label is rewound, and the ink layer of the magenta block is partially overlapped with the transfer material of the cyan color and transferred. After the label was rewound, the ink layer of the yellow block was transferred so as to partially overlap the transferred ink layer, and a multicolor printed matter was obtained on the same label.

[0058]

[Table 1] Here, primary transferability, transferability and color expression in superimposed printing as the first printing, and abrasion resistance of printed matter were evaluated by the following test methods. Primary transferability: After printing on an unprinted transfer medium with a thermal transfer printer, the printed matter was magnified with a microscope of 50 times, and it was visually observed whether or not the printed pattern was faithfully transferred to the printed pattern. Transferability in overprinting: After printing on the thermal transfer ink of the transfer medium that has already been thermally transferred by the thermal transfer printer, the printed matter is magnified with a microscope of 50 times and transferred to the printed pattern visually. I saw whether it was. Expression of colors in overprinting: After printing on the thermal transfer ink of the transfer medium that has already been thermally transferred by the thermal transfer printer, whether the printed matter expresses the desired color by the subtractive color mixing method, I saw if there were any irregularities. Abrasion resistance of printed matter: After printing was performed with a thermal transfer printer, the state of the printed matter was observed when the printed matter was rubbed 100 times with a 1 cm square felt / φ2 mm steel ball under a load of 200 g.

As is clear from Table 1, the printed matter printed on the thermal transfer recording medium of the present invention shown in Examples 1 to 7 is:
All of these are thermal transfer recording media having excellent primary transferability, good transferability and color reproducibility in overprinting, and excellent abrasion resistance of printed matter.

[0060] In contrast, the printed matter by thermal transfer recording medium of Comparative Example 1 and 2, upon heating, was bought evil transferability due to the elastic response too strong. Also, the abrasion resistance of the transferred area
Was relatively good.

Although the primary transferability of the thermal transfer recording medium of Comparative Example 3 was excellent, the transferability in overprinting was such that when reprinting was performed on these ink layers, these ink layers were melted. As a result, color unevenness due to ink mixing and transfer failure due to ink repelling were observed. Further, the scratch resistance of the printed matter was poor.

[0062]

As described above, the thermal transfer recording medium of the present invention is a thermal transfer recording medium in which a thermal transfer ink layer comprising at least a colorant and a thermoplastic resin is provided on a support. By using a material with viscoelastic properties, good printing can be performed even on a printing medium that has a surface state that is difficult to thermally transfer, and even when multiple colors are superimposed and thermally transferred, the transfer ink layer is beautiful. Because of the layered structure, good overprinting can be performed,
Also, the image after printing is also affected by strong mechanical rubbing, etc.
An excellent effect of maintaining a good printing state without falling off or being damaged is exhibited.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (3)

(57) [Claims] 1. A thermal transfer recording medium having a thermal transfer ink layer comprising at least a colorant and a thermoplastic resin on a support, wherein the thermoplastic resin is in a softened state over the entire temperature range of 100 to 150 ° C., and , Frequency 1 Hz in the linear viscoelastic region over the entire temperature range of 100 to 150 ° C
In the viscoelasticity measurement of the above, the thermal transfer ink layers of a plurality of colors characterized by exhibiting the following behaviors (a) and (b) are superimposed and printed,
Thermal transfer recording medium for multi-color printing . (A) Tan δ is 1.7 or more (b) Complex dynamic viscosity is 10 to 20000 Pa · S 2. The thermal transfer recording medium according to claim 1, wherein the colorant comprises at least a pigment, and the pigment comprises an organic pigment. 3. The colorant comprises at least an inorganic pigment,
2. The thermal transfer recording medium according to claim 1, wherein the ratio of the refractive index Np of the inorganic pigment to the refractive index Nr of the vehicle is in the range of Np / Nr = 1.12 to 1.00.