JP3299795B2 - Thermal transfer sheet - 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 sheet, and more particularly, to a heat transfer sheet having excellent printability on a low-smooth receptor.
Also, the present invention relates to a thermal transfer sheet having excellent friction resistance of a recorded image.

[0002]

2. Description of the Related Art As a conventional method for producing a thermal transfer sheet, a colorant and a hot-melt compound are melted at a high temperature and applied, or a hot-melt type is applied, or a colorant and a hot-melt compound are dissolved in an organic solvent. Or a method of applying a dispersed coating liquid is known, but the printed image on a hot-melt type thermal transfer sheet is insufficient in resolution, abrasion resistance, an organic solvent type is expensive, and However, manufacturing safety was a problem.

Various proposals have been made to solve these problems, some of which are described below.

(1) Colorant, melting point or softening point is 60 to 1
An ink which uses resin particles at 40 ° C., a wax having a melting point or softening point of 70 to 130 ° C., and a water-soluble resin as main components (JP-A-63-45091).

(2) Particles composed of a coloring agent and a thermoplastic resin, and those composed of wax particles and a water-soluble resin
3-89383).

(3) A resin emulsion comprising an acrylic resin, a vinyl acetate resin, and an ethylene resin emulsion composed of a colorant and a wax emulsion (Japanese Utility Model Application Laid-Open No. 3-178492, Japanese Patent Application Laid-Open No. 1-301285, Japanese Patent Application Laid-Open No. 137975).

The thermal transfer sheets described in the prior arts (1) to (3) can be obtained by granulating a heat-fusible compound.
The boundary between printing and non-printing can be clarified, the transfer layer is easily cut at the time of transfer, and the resolution is improved. However, (1)-(2)
In the method of (1), since a water-soluble resin is used as the binder, the effect of granulating the hot-melt compound is reduced, and the resolution is not sufficiently improved. The ball was not enough. Further, the method (3) has a disadvantage that the transferred image has insufficient strength and the frictional property of the image is poor.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a thermal transfer sheet which is excellent in resolution, printability on a low-smooth receptor, and image abrasion resistance. Is what you do.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that the heat-fusible compound used for the thermal transfer sheet has a content of 0.6.
The present inventors have found that it is effective to use an acrylic silicone emulsion as a binder by using particles having a particle size of about 3.0 μm, and have reached the present invention.

That is, the present invention relates to (1) a heat transfer sheet having an ink layer containing a colorant and a heat-meltable compound as main components on a support, wherein the heat-meltable compound has an average particle diameter of 0.6 (2) a thermal transfer sheet in the form of particles having a particle size of about 3.0 μm and using an acrylic silicon-based emulsion as a binder for the ink layer; In a thermal transfer sheet provided with an ink layer containing a heat-fusible compound as a main component, the heat-meltable compound in the ink layer and the release layer has an average particle size of 0.1.
A thermal transfer sheet having a particle size of 6 to 3.0 μm and using an acrylic silicone-based emulsion as a binder of the release layer is a gist.

According to the present invention, the heat-meltable compound used in the thermal transfer sheet is in the form of particles having a particle size of 0.6 to 3.0 μm, and the binder is made of an acrylic silicone emulsion. And the shear strength can be reduced, so that the heating at the time of printing causes cracks at the boundary between the continuous layer portion and the non-printed portion due to the fusion of grains, and the portion to be transferred becomes clear. It is estimated to be.

As a result, it is possible to form a printed image which is excellent in resolution and printability on a low-smooth receptor, and in which the slipping property of the binder is predominant and which is excellent in friction resistance.

[0013] Further, by using a constitution of a colorant layer and a release layer, by using particles of a heat-fusible compound of 0.6 to 3.0 μm in the release layer and acrylic silicone emulsion as a binder,
Friction resistance can be further improved without increasing the shear strength of the coating layer. That is, it is considered that the release layer serves as a protective layer on the printed image, and the protective layer has good slipperiness, thereby reducing deterioration of the image due to friction.

The acrylic silicone emulsion used in the present invention is obtained by disposing a silicone resin on an acrylic resin, wherein the strength and the binding strength of the acrylic resin coating film are imparted with the slipperiness of the silicone resin. The effect of the present invention can be obtained by using these. Further, it is thought that this is due to the molecular weight of the acrylic resin used.
When a film forming temperature of 40 ° C. or higher is used, the strength of a printed image after transfer is improved, and an image having more excellent abrasion resistance is obtained.

The heat-meltable compound used in the present invention includes:
An organic lubricant is used as a main component. Examples of the organic lubricant include carnauba wax, candelilla wax, rice wax, caster wax, montan wax and other natural waxes, derivatives of 12-hydroxystearic acid, modified polyethylene, α-olefin, maleic anhydride derivative, lanolin wax. Derivatives, amides such as aliphatic amides and aromatic amides are exemplified.

Carnauba wax is particularly preferred in terms of hardness and endothermic properties.

Further, a thermoplastic resin can be mixed with an organic lubricant as appropriate and used in a solid solution state. Various resins having a melting point or a softening point of 70 to 140 ° C can be used as those thermoplastic resins. Examples include acrylic resin, methacrylic resin, styrene resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, petroleum resin, terpene resin, olefin resin, polyester resin, polyacetal resin, and copolymers of these.

These are mixed with an optional dispersant and emulsifier,
Melt and mix well at temperatures above their melting point, then stir with a disperser etc. while adding water at 95 ° C, pre-emulsify, then emulsify under high pressure with a high-pressure homogenizer, target Is obtained.

The optimum particle size is 0.6 to 3.0 μm.
If it is less than 0.6 μm, the layer has a high shearing property and lacks image resolution. If it exceeds 3.0 μm, the printability on a low-smooth receptor is poor. The average particle size here is determined from the particle morphology observed from the cross section of the thermal transfer recording medium. For the cross-sectional observation, a sample is formed by an ordinary method, and a transmission electron microscope (TE
M). The particle size in the TEM observation and the particle size of the coating liquid for forming the ink layer substantially match. Therefore, it can be appropriately set according to the average particle size in the state of the coating liquid. The particle size of the coating solution can be easily measured by LA-700 manufactured by HORIBA, Ltd. using a laser diffusion method.

Examples of the support used in the present invention include plastic films having relatively high heat resistance, such as polyester, polycarbonate, triacetyl cellulose, nylon, and polyimide, glassine paper, condenser paper, metal foil, and the like. There is a thickness of about 2 to 15 μm,
Preferably it is in the range of 3 to 10 μm.

The surface of the support that is in contact with the thermal head (the surface opposite to the surface on which the ink layer exists) is
If necessary, by providing a heat-resistant protective layer made of silicone rubber, silicone resin, fluorine resin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, cellulose acetate propionate, etc. Heat resistance can be improved,
Alternatively, a support material that could not be used conventionally can be used.

The colorant is appropriately selected from conventionally known dyes and pigments.

[0023]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

The percentages and parts shown below are all based on weight. Example 1 4.5 μm thick polyethylene terephthalate (PE)
T) A coating liquid of the following ink layer was applied on a film using a wire bar so that the thickness after drying was about 2.5 μm, and dried with warm air at 60 ° C. to form an ink layer.

Preparation of Carnauba Wax Emulsion Carnauba Wax Emulsion 1) Carnauba Wax 27 parts Nonionic emulsifier (HLB14) 3.0 parts Water 70.0 parts Components other than water are mixed and mixed at 90 ° C., and the remaining hot water is mixed. Was added with stirring and pre-emulsified with a disperser. Thereafter, the mixture was emulsified with a high-pressure homogenizer and quenched with water to obtain an emulsion (the particle size distribution was measured by the above-described apparatus). The average particle size was 1.25 μm.

Preparation of Coating Solution for Ink Layer Carnauba wax emulsion (solid content 30%) (average particle diameter 1.2μ) 40 parts Acrylic acid ester silicone resin emulsion (solid content 32%, MFT 0 ° C) (manufactured by Showa Polymer Co., Ltd.) Polysol ROY-650 6) 8 parts Carbon black aqueous dispersion (solid content 15%) 26 parts Water 26 parts Example 2 The following ink layer was applied and formed in the same manner as in Example 1.

Carnauba wax emulsion as in Example 1 40 parts Acrylic ester silicone resin emulsion (solid content 50%, MFT 52 ° C.) (Nippon Synthetic Rubber Co., Ltd. SX800B) 5 parts Carbon black aqueous dispersion (solid content 15%) 26 parts Water 29 parts Example 3 A coating solution for the following release layer was applied on a 4.5 μm thick PET film using a wire bar to a dry thickness of 1.5 μm using a wire bar. The film was dried with air to form a release layer.

The carnauba wax emulsion (solid content: 30%) compounding ratio was the same as in Example 1, but only the average particle size was adjusted to 2.5 μm 59 parts The same acrylate silicone resin emulsion as in Example 1 6 parts Water 35 Then, after forming a release layer, the following coating solution for the ink layer was applied,
It was applied using a wire bar to a thickness of 1.5 μm after drying, and dried with 70 ° C. hot air to form an ink layer.

Carnauba wax / terbene resin (90/10 weight ratio) Emulsion (solid content 30%, average particle diameter 0.8 μ) 50 parts Carbon black aqueous dispersion (solid content 15%) 30 parts Water 20 parts Example 4 Polysol R manufactured by Showa Polymer Co., Ltd.
A release layer ink layer was formed in the same manner except that OY-6301 (solid content: 32%, MFT: 46 ° C) was used.

Comparative Example 1 The following ink layer coating liquid was applied in the same manner as in Example 1 to form an ink layer of Comparative Example.

Carnauba wax emulsion (solid content 30%) (average particle diameter 1.2 μ) 40 parts Acrylic ester emulsion (solid content 50%) 5 parts Carbon black aqueous dispersion (solid content 15%) 26 parts Water 29 Part Comparative Example 2 An ink layer was formed in the same manner as in Example 1 except that the carnauba wax emulsion having a particle diameter of 0.3 μm was used.

Comparative Example 3 An ink layer was formed in the same manner as in Example 1 except that the carnauba wax emulsion having a particle diameter of 4.5 μm was used.

Comparative Example 4 Polyvinyl alcohol (Kuraray PVA11) was used instead of the acrylate silicone resin of the release layer in Example 3.
A release layer and an ink layer were formed in the same manner except that 7) was used.

The thermal transfer sheets obtained in the above Examples and Comparative Examples were coated on a cast coated paper and a lightweight coated paper having a Beck smoothness of 200 seconds using a thermal transfer simulator under the following conditions. A solid pattern was printed and evaluated according to the following method. Table 1 shows the results.

Printing conditions Printing speed 100 mm / sec, Thermal head used: Thin film part glaze 8 dots / mm.

Evaluation Method Thermal Sensitivity: A bar code is printed on cast-coated paper in the vertical direction, and the decoding rate is determined by LASER CHECK 2811.
(Symbol Technologies) and the value is 9
It is represented by the minimum applied energy of 0 or more.

Resolution: A bar code in the vertical direction was printed under the same conditions as above, and the evaluation was made based on the decoding rate.

Void: A bar code and a solid are printed on a light-weight coated paper having a Beck smoothness of 200 seconds, and evaluated by the bulge of the printed portion.

：: good bulge in the printed area; ×: spills are noticeable in the printed area.

Image friction resistance: A bar code is printed on cast-coated paper, and the printed image is subjected to a load of 100 g at 50 ° C.
/ Cm ² , rub 100 times with cardboard, and evaluate the image by disturbance.

◎: No image distortion at all, ：: Some image distortion, but readable, ×: Image distortion, unreadable.

[0042]

[Table 1]

From the results shown in Table 1, it can be seen that the thermal transfer sheet of the present invention is excellent in thermal sensitivity, resolution, printing quality on low-smooth paper, and also excellent in abrasion resistance.

[0044]

The thermal transfer sheet of the present invention has a particle diameter of 0.6.
By using an emulsion of acrylic silicone resin as the hot-melt compound of ~ 3.0μ and the binder, it is excellent in recording sensitivity, resolution, printability on low-smooth paper, and also friction resistance. Are better.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinji Okada 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-63-158291 (JP, A) JP-A Sho JP-A-1-301285 (JP, A) JP-A-3-178486 (JP, A) JP-A-5-24368 (JP, A) JP-A-5-338359 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (3)

(57) [Claims] 1. A thermal transfer sheet comprising a support and an ink layer comprising a colorant and a heat-fusible compound as main components,
A thermal transfer sheet characterized in that the heat-fusible compound is in the form of particles having an average particle diameter of 0.6 to 3.0 [mu] and an acrylic silicone emulsion is used as a binder for the ink layer. 2. In a thermal transfer sheet having a release layer mainly composed of a heat-fusible compound and an ink layer mainly composed of a coloring agent and a heat-fusible compound on a support, said ink layer and said release layer are provided. The heat fusible compound in the average particle diameter 0.6 ~
A thermal transfer sheet having a particle size of 3.0 μm and using an acrylic silicone-based emulsion as a binder of a release layer. 3. The thermal transfer sheet according to claim 1, wherein an acrylic silicone emulsion having an MFT of 40 ° C. or higher is used as a binder.