JP2002248871A - Sublimation type thermal transfer recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sublimation type thermal transfer recording medium having excellent image uniformity and heat response by facilitating a heat transfer to a dye transfer contributing layer of a sublimable dye in a dye supply layer by specifying a Tg of the dye transfer contributing layer to a specific value lower than the specific Tg of the dye supply layer and thereby being not liable to affect an influence of a resistance value unevenness or the like of a thermal head. SOLUTION: The sublimation type thermal transfer recording medium comprises an ink layer having the dye supply layer and the dye transfer contributing layer for dispersing the sublimable dye in an organic binding agent and sequentially laminated from a base side on the base. In this medium, the organic binding agent of the dye supply layer is a resin having a glass transition temperature (hereinafter referred to as 'Tg') of 60 to 150 deg.C or higher. The organic binding agent of the dye transfer contributing layer has Tg of 0 to 60 deg.C and contains a reaction product with a compound having an isocyanate or the like and an active hydrogen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sublimation type thermal transfer recording medium.

[0002]

2. Description of the Related Art JP-A-2-233293 discloses that in a sublimation type thermal transfer recording medium in which a substrate, a dye supply layer and a dye transfer contributing layer are laminated in this order, the organic binder of the dye transfer contributing layer is 60 to 150. Sublimation type thermal transfer recording medium, characterized in that the resin is a resin having a Tg of 0 ° C. and the organic binder of the dye supply layer is a resin having a Tg of 0 to 60 ° C. The Tg rule is reversed, and in order to prevent the precipitation of the dye particles from the dye supply layer on the surface of the dye transfer contribution layer, (dye transfer contribution layer)> (dye supply layer) in Tg. Then, the dye hardly enters the dye transfer contributing layer, the transfer density is low, and the thermal responsiveness is poor. Also, JP-A-2-399
No. 94, a substrate, a dye supply layer formed by dispersing a sublimable dye in an organic binder, and a dye transfer contributing layer in the sublimation type thermal transfer recording medium laminated in order, the dye transfer contributing layer, A sublimation-type thermal transfer recording medium characterized by containing a reaction product of an isocyanate and a compound having active hydrogen as an organic binder resin has been described. In the present invention, it is intended to improve the image uniformity by defining the Tg of the resin of the dye transfer contributing layer and the dye supply layer. Further, JP-A-2-286289 discloses a substrate,
In a sublimation type thermal transfer recording medium comprising a coloring material layer comprising a sublimable dye and a binder and a protective layer, a thermal transfer recording sheet characterized in that the protective layer is a polyvinyl butyral resin is described. If the performance is out of the allowable range, fusion with image quality occurs.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dye transfer contributing layer having a specific Tg lower than a specific Tg of a dye supply layer, so that the sublimable dye in the dye supply layer has a specific transfer function. By providing a sublimation type thermal transfer recording medium having excellent image uniformity by facilitating heat transfer to the layer, thereby having excellent thermal responsiveness and less susceptible to unevenness in resistance value of the thermal head. is there.

[0004]

The object of the present invention is to provide (1) a dye supply layer and a dye in which a sublimable dye is dispersed in an organic binder in order from the substrate side on the substrate. In a sublimation type thermal transfer recording medium provided with an ink layer in which a transfer contributing layer is laminated, the organic binder of the dye supply layer is a resin having a glass transition temperature of 60 to 150 ° C. or more, and 0-60 organic binder in the layer
A sublimation-type thermal transfer recording medium, which is a resin having a glass transition temperature (hereinafter, abbreviated as Tg) of 0 ° C., and contains a reaction product of an isocyanate and a compound having active hydrogen. 2) "The resin of the dye supply layer is
(1) wherein the resin is of the same type as the resin used as the organic binder of the dye transfer contributing layer.
Sublimation-type thermal transfer recording medium according to item 1), (3) a resin comprising an intermediate layer provided between a substrate and a dye supply layer, wherein the intermediate layer is used as an organic binder of the dye transfer contributing layer. (4) The dye transfer-contributing layer contains a substance having lubricity or releasability. (5) The dye transfer-contributing layer having a thickness of 0.1 to 0.1.
Sublimation type thermal transfer recording medium according to the above item (1), characterized by having a thickness of 35 μm ”, (6)“ At least two layers of an ink layer composed of a sublimable dye and a binder resin are laminated on the substrate and provided. Wherein the upper ink layer has a dye concentration gradient having a low dye concentration and / or a dye diffusion coefficient gradient having a small dye diffusion coefficient. The thermal transfer sheet according to the above (1), wherein the relative speed with respect to the thermal transfer image receiving member is 1 / n times (n> 1) and multiple simultaneous writing by the end face head is possible. You.

Hereinafter, the present invention will be described in detail. As shown in FIG. 1, a dye supply layer (2) composed of a sublimable dye and a polymer binder resin and a dye transfer contributing layer (1) are laminated on a substrate (3) in this order, and as shown in FIG. If necessary, an intermediate layer (4) may be provided between the substrate and the dye supply layer for the purpose of improving adhesiveness or the like, as shown in FIG. A lubricating layer (5) may be provided for the purpose of improvement or the like. Further, a heat-resistant lubricating layer (6) may be provided on the other surface of the ink layer as needed.

Next, materials and amounts used for the sublimation type thermal transfer sheet of the present invention will be described. << Dye Transfer Contributing Layer >> Examples of the type of the binder polymer compound having active hydrogen used for the dye transferring contributing layer include polyvinyl butyral, polyvinyl acetal, polyurethane polyol, polyether polyol, polyester polyol, vinyl chloride resin, and vinyl acetate. Resin, polyamide, polyethylene, polycarbonate, polystyrene,
Polypropylene, acrylic resin, phenolic resin, polyester, polyurethane, epoxy resin, silicone resin, fluororesin, melamine resin, natural rubber, synthetic rubber,
Examples include polyvinyl alcohol and cellulose resin. Among them, those having Tg: 0 to 60 ° C as physical properties are selected and used. As described above, the same kind of resin in the present invention means a resin having the same main skeleton of the resin or the same main skeleton before modification (cross-linking or the like), and is generally a homolog or a homolog. I do. The thickness of the dye transfer contributing layer is generally 0.05 to 5 μm, preferably 0.1 to 5 μm.
2 μm.

As the isocyanate compound, a di-isocyanate compound or a tri-isocyanate compound is particularly effective. Examples include diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, isophorone diisocyanate, bisisocyanate methylcyclohexane, and trimethylhexamethylene diisocyanate.

The ratio of the —NCO group of the isocyanate compound to the —OH group of the resin having active hydrogen is 0.1: 1 to 1: 1.
It is appropriate to mix at a ratio of In order to obtain a high gel fraction by reacting a resin having active hydrogen with an isocyanate compound, it cannot be obtained only by coating and drying the intermediate layer. Can be obtained only by aging. In order to reduce the high-temperature aging as much as possible, a curing catalyst may be used. As such a curing catalyst, acids, bases, metal compounds and the like are effective, and it is desirable to use a tin-based catalyst for the reaction between a resin having active hydrogen and an isocyanate compound.

<< Dye Supply Layer >> The binder used in the dye supply layer is of the same kind as the binder of the dye transfer contributing layer. These resins can be used alone, but several kinds of resins can be used. You may mix or use a copolymer. Further, the dye supply layer may contain known additives such as a lubricant, a curing agent, a dispersant, and an antioxidant.

As the sublimable dye, sublimation at 60 ° C. or more,
Alternatively, any dye that evaporates may be used as long as it is mainly used in thermal transfer printing, such as a disperse dye or an oil-soluble dye. I. Disperse yellow 1,3,8,9,
16, 41, 54, 60, 77 and 116, and C.I. I. Disperse Red 1,4,6
11, 15, 17, 55, 59, 60, 73, 83 and the like. I. Disperse Blue 3,
14, 19, 26, 56, 60, 64, 72, 99, 1
08 and the like, and C.I. I. Solvent Yellow 77, 116, and C.I. I. Solvent Red 23, 25 and 27, and C.I. I. Solvent Blue 36, 83, 105 and the like. One type of these dyes can be used, but a mixture of several types can be used.

In order to stably supply the dye for a long time and maintain good printing characteristics, the dye supply layer preferably contains at least an undissolved particulate sublimable dye. here,
The undissolved particles mean dyes that cannot be completely dissolved in the organic binder after drying the ink (organic binder + sublimable dye + solvent) at the time of forming the ink layer and precipitate as particles. The presence of the undissolved particulate dye also differs depending on the solvent, even for the adhesive and the dye. The presence or absence of the undissolved particulate dye can be easily identified by an electron microscope after forming the dye supply layer. The particle size of the undissolved particulate dye varies with the dye supply layer thickness,
0.01 μm to 20 μm, preferably 1.0 to 5.0 μm
m.

<< Substrate & Heat Resistant Layer >> As the substrate, a film having relatively high heat resistance, for example, polyester, PEE
K, PEN, PET, polystyrene, polysulfone,
Films of aromatic polyamide, polyimide, polycarbonate, triacetyl cellulose and the like can be mentioned, and among them, polyester, PEEK, PEN, aromatic polyamide and polyimide film are preferable. Further, these films may be provided with a known heat-resistant lubricating layer, if necessary.

<< Intermediate Layer >> The binder used for the intermediate layer is of the same type as the dye transfer contributing layer, and these resins can be used alone, but several kinds may be mixed or co-polymerized. Coalescing may be used. Known lubricants in the dye supply layer,
It may contain additives such as a curing agent, a dispersant, and an antioxidant.

As a multi-use ribbon, the present inventors have
A sublimation type thermal transfer body having a laminated structure proposed in Japanese Patent Application Laid-Open No. 2-586, "Dye release ability between dye supply layer and dye transfer contributing layer: dye supply layer> dye transfer contributing layer". preferable. In detail, the dye supply layer and the dye transfer contributing layer are formed as a single layer on the substrate with the same amount of adhesion in each of the respective formulations, each of which is overlapped with another image receiving layer and the same thermal energy is applied to both. When the voltage is applied, the amount of dye transferred to each image receiving layer is in the relationship of dye supply layer> dye transfer contributing layer.

According to the findings of the present inventors, the diffusion of the dye in the ink layer is based on Fick's law, that is, the amount dn of the dye which has passed through the cross-sectional area q per unit time is represented by the density gradient dc of the dye in the diffusion direction. / Dx, and D is the average diffusion coefficient of each part in the ink layer when heat is applied,

[0016]

## EQU1 ## The relationship dn = -D * (dc / dx) * q * dt applies.

Therefore, means for facilitating the diffusion and supply of the sublimable dye from the dye supply layer to the dye transfer contributing layer are as follows: I) Regarding the dye concentration, the relation of dye supply layer> dye transfer contributing layer is satisfied; And / or II) There is a means for relating the diffusion coefficient in each layer to the relationship of dye supply layer> dye transfer contributing layer.

[0018]

The present invention will be specifically described below with reference to examples.
In addition, the amount of each component in the following description is part by weight. (Conditions for preparing a thermal transfer sheet) On the other surface of an aromatic polyamide film having a thickness of 4.5 μm having a silicone-based heat-resistant layer having a thickness of 0.6 to 1 μm, an intermediate layer having a thickness of 0.3 μm
m, the dye supply layer was 6 μm in thickness, and the dye transfer contributing layer was formed as in each example, and dried at 100 ° C. for 3 minutes to prepare a sublimation transfer sheet.

[Example 1] (Dye supply layer) Polyvinyl butyral resin BX-1 (Tg: 85 ° C) (manufactured by Sekisui Chemical) 7 parts Sublimable dye MS Cyan Vp (manufactured by Mitsui Toatsu Dye) 24 parts n-hexanol 69 parts

(Dye transfer contributing layer) Polyether polyol resin E550 (Tg: 10 ° C.) (Takeda Chemical) 5 parts Isocyanate WD830 (Takeda Chemical) 3 parts Ethanol 92 parts Film thickness: 0.5 μm

Example 2 (Dye supply layer) Polyvinyl butyral resin BX-1 (Tg: 85 ° C.) (manufactured by Sekisui Chemical) 7 parts Sublimable dye MS Cyan Vp (manufactured by Mitsui Toatsu Dye) 24 parts n-hexanol 69 parts

(Dye transfer contributing layer) Polyvinyl butyral resin BLS (Tg: 54 ° C.) (Sekisui Chemical) 5 parts Isocyanate WD830 (Takeda Chemical) 3 parts Ethanol 92 parts Film thickness: 0.5 μm

[Example 3] (Intermediate layer) Polyvinyl butyral resin 6000EP (manufactured by Denki Kagaku Kogyo) 2.8 parts Aziridine compound PZ-33 (manufactured by Nippon Shokubai) 0.3 parts Toluene 29.1 parts MEK 67.9 parts

* Example 2 shows the dye supply layer and the dye transfer contributing layer.
Same as

Example 4 (Intermediate layer) Polyvinyl butyral resin 6000EP (manufactured by Denki Kagaku Kogyo) 2.8 parts Aziridine compound PZ-33 (manufactured by Nippon Shokubai) 0.3 part Toluene 29.1 parts MEK 67.9 parts

(Dye supply layer) Polyvinyl butyral resin BX-1 (Tg: 85 ° C.) (manufactured by Sekisui Chemical) 7 parts Sublimation dye MS Cyan Vp (manufactured by Mitsui Toatsu Dye) 24 parts n-hexanol 69 parts

(Dye transfer contributing layer) Polyvinyl butyral resin BLS (Tg: 54 ° C.) (Sekisui Chemical) 5 parts Isocyanate WD830 (Takeda Pharmaceutical) 3 parts Silicone oil SF8427 (Toray Dow) 1 part Silicon filler Tospearl 120 (GE Toshiba) Silicone) 3 parts Ethanol 88 parts Film thickness: 0.5 μm

Example 5 * Intermediate layer and dye supply layer were the same as in Example 4.

(Dye transfer contributing layer) Polyvinyl butyral resin BLS (Tg: 54 ° C.) (Sekisui Chemical) 5 parts Isocyanate WD830 (Takeda Chemical) 3 parts Silicone oil SF8427 (Toray Dow) 1 part Silicon filler Tospearl 120 (GE Toshiba) Silicone) 3 parts Teflon filler Lubron L5 (Daikin Industries) 5 parts Ethanol 83 parts Film thickness: 0.35 μm

[Comparative Example 1] (Dye supply layer) Polyvinyl butyral resin BX-1 (Tg: 85 ° C) (manufactured by Sekisui Chemical) 7 parts Sublimable dye MS Cyan Vp (manufactured by Mitsui Toatsu Dye) 24 parts n-hexanol 69 parts

(Dye transfer contributing layer) Polyvinyl butyral resin 6000C (Tg: 92 ° C.) (Denki Kagaku Kogyo) 5 parts Isocyanate WD830 (Takeda Pharmaceutical) 3 parts Ethanol 92 parts Film thickness: 0.5 μm

<Receiving paper> A liquid having the following formulation was applied on synthetic paper (Yupo: manufactured by Oji Yuka) and dried to a thickness of 6 μm.
Was formed. Vinyl chloride resin 1000GKT (manufactured by Denki Kagaku Kogyo) 9 parts Isocyanate D103H (manufactured by Takeda Pharmaceutical) 4 parts Curing acceleration catalyst TK1L (manufactured by Takeda Chemical) 0.06 parts Silicone oil SF8427 (manufactured by Toray Dow Silicone) 0.5 part Silicone oil SH200 (made by Toray Dow Silicone) 0.5 parts Toluene 10 parts MEK 30 parts

In Examples 1 to 4 and Comparative Example 1, recording was performed under the conditions of a thermal head resolution of 12 dots / mm, applied energy of 0.64 mj / dot, and applied voltage of 0.12 W / dot. / Mm applied energy: 0.64 mj / dot, applied voltage: 0.16 W / dot, feed speed during recording (15 times speed), image receiving sheet: 8.4 mm / sec, ink sheet: 0.6 mm / sec. Recording was performed by the speed difference mode method recording. Table 1 shows the results.

[0034]

[Table 1]

[0035]

As is apparent from the detailed and concrete description, by defining Tg as in claim 1 of the present invention, the sublimable dye in the dye supply layer can be transferred to the dye transfer contributing layer. By facilitating the heat transfer, excellent thermal responsiveness can be obtained, and the thermal head can be made less susceptible to uneven resistance. By using the same kind of resin for the dye supply layer and the dye transfer contributing layer as in claim 2, the adhesiveness between the two layers is improved, and layer peeling can be suppressed. By providing an intermediate layer and using the same type of resin for the intermediate layer, the dye supply layer, and the dye transfer contributing layer, the adhesion between the layers can be further increased, and layer peeling can be suppressed. By adding lubricity and releasability to the dye transfer-contributing layer, it is possible to suppress fusion with the paper receiver. By reducing the thickness of the dye transfer contributing layer, the thermal sensitivity is improved and the image density is improved. As described in claim 6, the dye supply layer has two or more layers, and the upper ink layer has a dye concentration gradient with a low dye concentration and / or a dye diffusion coefficient gradient with a small dye diffusion coefficient. To the sublimation multi-transfer sheet. According to a seventh aspect of the present invention, the print transport speed of the sublimation transfer sheet is set at a relative speed 1 /
It can also be used as a sublimation multi-transfer sheet characterized by recording with n (n> 1).

[Brief description of the drawings]

FIG. 1 is a sectional view showing a sublimation type thermal transfer recording medium according to the present invention.

FIG. 2 is another diagram showing a cross-sectional view of the sublimation type thermal transfer recording medium of the present invention.

FIG. 3 is yet another diagram showing a cross-sectional view of the sublimation type thermal transfer recording medium in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dye transfer contribution layer 2 Dye supply layer 3 Substrate 4 Intermediate layer 5 Slip layer 6 Heat-resistant slip layer

Claims (7)

[Claims] 1. A sublimation-type thermal transfer method comprising the steps of: providing a dye supply layer formed by dispersing a sublimable dye in an organic binder and an ink layer formed by laminating a dye transfer contributing layer on a substrate in order from the substrate side. In the recording medium, the organic binder of the dye supply layer is a resin having a glass transition temperature of 60 to 150 ° C. or more, and the organic binder of the dye transfer contributing layer is 0.
A sublimation-type thermal transfer recording medium, which is a resin having a glass transition temperature (hereinafter, abbreviated as Tg) of -60 ° C. and contains a reaction product of an isocyanate and a compound having active hydrogen. 2. The sublimation type thermal transfer according to claim 1, wherein the resin of the dye supply layer is of the same type as the resin used as the organic binder of the dye transfer contributing layer. recoding media. 3. An intermediate layer provided between a substrate and a dye supply layer, wherein the intermediate layer is of the same type as a resin used as an organic binder of the dye transfer contributing layer. The sublimation type thermal transfer recording medium according to claim 1. 4. The sublimation type thermal transfer recording medium according to claim 1, wherein the dye transfer contributing layer contains a substance having lubricity or releasability. 5. The dye transfer-contributing layer having a thickness of 0.1 to 0.1.
The sublimation type thermal transfer recording medium according to claim 1, wherein the thickness is 35 µm. 6. An ink layer comprising at least two layers of a sublimable dye and a binder resin is provided on a substrate by laminating the same, and the upper ink layer has a low dye concentration gradient and / or a low dye diffusion coefficient. 2. The thermal transfer recording medium according to claim 1, having a dye diffusion coefficient gradient. 7. A relative speed to a thermal transfer image receiving member is 1 / n.
2. The thermal transfer sheet according to claim 1, wherein multiple simultaneous writing by an end face head is possible at double (n> 1). 3.