KR19990033135A - Thermal transfer recording media - Google Patents

Abstract

The present invention is a base film (base film); A protective layer formed on one surface of the substrate; And a thermal transfer recording medium having a non-transfer layer and a transfer layer sequentially formed on the other side of the substrate, wherein the non-transfer layer includes conductive carbon black, a diaryl phthalate resin, and a thermoplastic resin. It is done. The thermal transfer recording medium of the present invention improves the dispersibility of carbon black in the composition for forming a non-transfer layer by using a conductive carbon black as a filler when forming the non-transfer layer and a thermoplastic resin and a DAP resin as a binder. The viscosity of is reduced as compared with the conventional case. In addition, the surface resistance of the non-transfer layer, the protective layer and the transfer layer is 10 ⁵ Ω / ㎝ or less, excellent antistatic function, the amount of static electricity generated during printing is greatly reduced. As a result, the thermal head of the barcode printer or facsimile is prevented from being damaged by static electricity. In addition, the glossiness of the thermally transferred image may reduce eye fatigue when reading the output image.

Description

Thermal transfer record carrier

The present invention relates to a thermal transfer recording medium, and more particularly, to a thermal transfer recording medium used in a computer, a word processor, a bar code printer, a facsimile, and the like.

The structure of the conventional thermal transfer recording medium is shown in FIG. Referring to this, the protective layer 12 is formed on one surface of the substrate 11, and the non-transfer layer 13 and the transfer layer 14 are sequentially formed on the other surface of the substrate.

The non-transfer layer 13 provides a matting effect on the surface of the transferred image to facilitate the reading of the barcode and to reduce eye fatigue when reading the output image. And it has an antistatic function to remove the static electricity generated when printing serves to prevent the thermal head (thermal head) such as barcode printer, facsimile damage by static electricity.

On the other hand, the non-transfer layer is made of a composition comprising a filler and a binder. As the filler, inorganic materials such as carbon black, silica, titanium oxide, calcium carbonate, alumina, talc, and powdered organic materials such as silicone resin, acrylic resin, melamine resin, and urea resin are used. use. And as a binder, a thermoplastic resin is used.

By the way, when forming a non-transfer layer with the above-mentioned composition, the following problems arise.

First, since conductive carbon black absorbs solvents very well, the viscosity of the composition for forming a non-transfer layer is high and the stability of the composition is poor.

Second, the dispersibility of the conductive carbon black is not so good that a satisfactory antistatic function cannot be obtained.

The technical problem to be solved by the present invention is to solve the above problems, there is little amount of static electricity generated during printing, there is no damage to the thermal head, such as a barcode printer, facsimile, and the gloss of the thermal transfer image can be reduced to reduce eye fatigue To provide a thermal transfer recording medium.

1 is a view showing the structure of a general thermal transfer recording medium.

<Explanation of symbols for main parts of the drawings>

11 ... substrate 12 ... protective layer

13 ... Non-transcription 14 ... Transcription

In the present invention to achieve the above technical problem, a base film; A protective layer formed on one surface of the substrate; And a non-transfer layer and a transfer layer sequentially formed on the other side of the substrate, the thermal transfer recording medium comprising:

The non-transfer layer provides a thermal transfer recording medium comprising a conductive carbon black, a diaryl phthalate resin, and a thermoplastic resin.

The present invention is characterized by using a conductive carbon black as a filler when forming a non-transfer layer, and using a mixture of a thermoplastic resin and a diallyl phthalate (DAP) resin as a binder. Thus, when the DAP resin and the thermoplastic resin are used together as a binder, the viscosity of the non-transfer layer forming composition can be lowered as compared with the conventional case, and the dispersibility of the conductive carbon black can be obtained.

The thermal transfer recording medium of the present invention is manufactured by forming a protective layer by heat-resistant coating on one side of the substrate, and forming the non-transfer layer and the transfer layer on the other side of the substrate in the same manner as in the conventional thermal transfer recording medium. . The surface resistance of the protective layer, the non-transfer layer, and the transfer layer formed at this time is 10 ⁵ Ωcm or less.

As the substrate, a polyethylene terephthalate film, a polyamide film, a PVC film, a polyethylene film, a polypropylene film, a polyimide film, a polysulfone film, a polycarbonate film, and the like are used. Among them, a polyethylene terephthalate film is mainly used. . It is preferable that the thickness of a base material is 2-20 micrometers here.

The protective layer is required to be heat resistant as a part in contact with the thermal head. As a material for forming such a protective layer, a silicone resin, a fluorine resin, an epoxy resin, a phenol resin, a melamine resin, a nitrocellulose resin, or the like is used.

The non-transfer layer is composed of a composition comprising a filler and a binder, in some cases may further comprise a crosslinking agent. At this time, it is preferable that the thickness of a non-transfer layer is 0.2-3 micrometers. If the thickness of the non-transfer layer is less than 0.2 mu m, the matting and antistatic effect is lowered.

As the filler, conductive carbon black having a particle diameter of 0.3 to 5 μm is used.

As the binder, a thermoplastic resin and a DAP resin are mixed and used as described above. The DAP resin used in the present invention includes a phthalic acid DAP resin, an isophthalic acid DAP resin, a terephthalic acid DAP resin, and the content thereof is preferably 20 to 60% by weight based on the conductive carbon black. When the content of the DAP resin is less than 20% by weight, the effect of improving the viscosity of the composition for forming a non-transfer layer and the dispersibility of conductive carbon black is insignificant. On the other hand, when the content of the DAP resin exceeds 60% by weight, the adhesion between the non-transfer layer and the substrate is weakened, which is not preferable.

As the thermoplastic resin, at least one selected from the group consisting of nitrocellulose, polyester resin, polyurethane, polystyrene, vinyl chloride-vinylacetate copolymer, acrylic resin, nylon resin and polyvinyl butyral resin is used. And the content of the thermoplastic resin is suitably 20 to 80% by weight based on the conductive carbon black.

The transfer layer is composed of a composition comprising a colorant, a binder, and a heat-melt material, with a thickness of 2 to 7 μm. If the thickness of the transfer layer is less than 2 μm, the blackness of the printed image is insufficient, and if the thickness of the transfer layer is more than 7 μm, thermal sensitivity is poor and not preferable.

As the colorant, organic or inorganic dyes or pigments are used, for example, carbon black and the like. The transfer layer forming composition may further include an additive such as a plasticizer, if necessary.

As the binder, a thermoplastic resin having a softening point of 70 to 140 ° C. is used, and an acrylic resin, ethylene-vinylacetate resin, styrene resin, polyvinyl resin, petroleum resin, polyester resin, polyacetal resin, and the like are used.

As the heat-melt material, a wax having a softening point of 60 to 130 ° C. is generally used. Specific examples thereof include carnauba wax, candelira wax, paraffin wax, Bees wax, rice wax, polyethylene wax, micro-crystalline wax, montan wax and the like are used. As the solvent, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone are used.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited only to the following Examples.

<Example 1>

A protective layer made of a silicone resin was formed on one surface of a polyethylene terephthalate film (thickness: about 4.5 μm). Subsequently, the composition for forming a non-transcription layer was applied to the other side of the polyethylene terephthalate film, and then dried at 100 ° C. for 60 seconds to form a 1 μm thick non-transcription layer.

The non-transfer layer forming composition is conductive carbon black (Ketzen black, Lion Akzo) 10% by weight, DAP (Diaso) 4% by weight, polyurethane (CA-139, Morton) 6% by weight and methyl ethyl ketone 80% % Was prepared by dispersing in a ball mill for about 20 hours.

A thermal transfer recording medium was completed by applying a transfer layer forming composition on the non-transfer layer to form a transfer layer.

The transfer layer forming composition is carbon black (MA-100, Mitsubishi Carbon Co.) 15 parts by weight, EVA 250 (ethylene-vinylacetate copolymer, DuPont) 10 parts by weight, carnauba wax (type # 2) 25 Weight%, 40 parts by weight of paraffin wax (HNP5, Nippon Solder) and 15 parts by weight of rosin were prepared by dispersing in a ball mill for 6 hours at 100 ° C.

<Example 2>

Composition for forming a non-transfer layer is 10% by weight conductive carbon black (Ketzen black, Lion Akzo), 4% by weight DAP (Diaso), 2% by weight of nitrocellulose (1/8 second, microfiber), polyurethane (CA- 139, Morton) 4% by weight and 80% by weight of methyl ethyl ketone were prepared in the same manner as in Example 1, except that it was prepared by dispersing in a ball mill for about 20 hours.

Comparative Example 1

The non-transfer layer forming composition was prepared by dispersing 10 wt% of conductive carbon black (Ketzen black, Lion Akzo), 10 wt% of polyester resin (vylon200, Toyobo) and 80 wt% of methyl ethyl ketone in a ball mill for about 20 hours. Except what was carried out, it carried out according to the same method as Example 1.

Comparative Example 2

The composition for forming the non-transfer layer was formed by ball milling using 10% by weight of carbon black (printex25, Degussa), 4% by weight of DAP (Diaso), 6% by weight of polyurethane (CA-139, Morton) and 80% by weight of methyl ethyl ketone. The same procedure as in Example 1 was conducted except that the dispersion was prepared for about 20 hours.

Comparative Example 3

The composition for forming a non-transfer layer is 10 wt% conductive carbon black (Ketzen black, Lion Akzo), 6 wt% polyester resin (vylon200, Toyobo), 4 wt% polyvinyl resin (VAGH, UCC) and methyl ethyl ketone The same procedure as in Example 1 was conducted except that 80 wt% was prepared by dispersing in a ball mill for about 20 hours.

<Comparative Example 4>

A protective layer made of a silicone resin was formed on one surface of a polyethylene terephthalate film (thickness: about 4.5 μm). Subsequently, the thermal transfer recording medium was completed by applying the transfer layer forming composition to the other surface of the polyethylene terephthalate film to form a transfer layer.

The transfer layer forming composition is carbon black (MA-100, Mitsubishi Carbon Co.) 15 parts by weight, EVA 250 (ethylene-vinylacetate copolymer, DuPont) 10 parts by weight, carnauba wax (type # 2) 25 By weight, 40 parts by weight of paraffin wax (HNP5, Nippon Solder) and 15 parts by weight of rosin were prepared by dispersing in a ball mill for 6 hours at 100 ° C.

Comparative Example 5

The composition for forming a non-transfer layer was dispersed in a ball mill for 10 hours by weight of conductive carbon black (Ketzen black, Lion Akzo) 10% by weight of polyurethane (CA-139, Morton) and 80% by weight of methyl ethyl ketone Except for the preparation, it was carried out according to the same method as in Example 1.

The properties of the composition for forming a non-transcription layer according to Example 1-2 and Comparative Example 1-5 were evaluated as follows.

The viscosity of the composition for forming a non-transparent layer is evaluated by measuring the viscosity at room temperature using a Brookfield viscometer, and the dispersibility of carbon black in the composition for forming a non-transparent layer is determined by an optical densitometer. Measured and evaluated.

With reference to the above-mentioned evaluation method, the viscosity of the composition for forming a non-transcription layer prepared according to Example 1-2 and Comparative Example 1-5, the dispersibility of carbon black in the composition for forming a non-transcription layer, the non-transfer layer, the protective layer The surface resistance of the transfer layer and the amount of static electricity generated during printing are measured and shown in Table 1 below.

division Viscosity of Composition for Non-Transfer Layer (cps) Dispersibility of Carbon Black in Compositions for Non-Transfer Layers Surface resistance (Ω㎝) The amount of static electricity generated during printing (kV) Non-transcription layer Protective layer Warrior Layer Example 1 500 Good 10 ⁵ or less 10 ⁵ or less 10 ⁵ or less 0.05 Example 2 400 Good 10 ⁵ or less 10 ⁵ or less 10 ⁵ or less 0.05 Comparative Example 1 10,000 Bad 10 ⁷ 10 ¹⁰ 10 ⁸ 1.0 Comparative Example 2 350 Good 10 ⁷ 10 ¹¹ 10 ⁸ 2.0 Comparative Example 3 5,000 Bad 10 ⁷ 10 ¹⁰ 10 ⁸ 2.0 Comparative Example 4 - - - 10 ¹² 10 ¹¹ 6.0 Comparative Example 5 5,000 Bad 10 ⁷ 10 ¹⁰ 10 ⁸ 2.0

As can be seen from Table 1, when the DAP resin and polyurethane are used together as a binder (Example 1), and when the DAP resin, nitrocellulose and polyurethane are used together (Example 2), The viscosity of the composition was low and the dispersibility of carbon black was good. In addition, the surface resistance of the non-transfer layer, the protective layer and the transfer layer was low, so the amount of static electricity generated during printing was small.

On the other hand, when only polyester resin is used as a binder (Comparative Example 1), when polyester resin and polyvinyl resin are used together as a binder (Comparative Example 3) and when only polyurethane is used as a binder (Comparative Example 5) The viscosity of the composition for sand layer formation was very high compared with the case of Example 1-2, and the dispersibility of carbon black was poor. In addition, the surface resistance of the non-transfer layer, the protective layer and the transfer layer was high, the amount of static electricity generated during printing was high.

When DAP resin and polyurethane are used together as a binder and general carbon black is used as a filler (Comparative Example 2), the viscosity of the non-transfer layer forming composition and the dispersibility of the carbon black in the composition are good. The surface resistance of the layer and the transfer layer was high and the amount of static electricity generated during printing was high.

When the non-transfer layer was not formed (Comparative Example 4), the surface resistances of the protective layer and the transfer layer were high and the amount of static electricity generated during printing was high.

In the thermal transfer recording medium of the present invention, conductive carbon black is used as a filler when the non-transfer layer is formed, and a thermoplastic resin and a DAP resin are used together as a binder to improve the dispersibility of the carbon black in the composition for forming a non-transfer layer. The viscosity of is reduced as compared with the conventional case. In addition, the surface resistance of the non-transfer layer, the protective layer and the transfer layer is 10 ⁵ Ω / ㎝ or less, excellent antistatic function, the amount of static electricity generated during printing is greatly reduced. As a result, the thermal head of the barcode printer or facsimile is prevented from being damaged by static electricity. In addition, the glossiness of the thermally transferred image may reduce eye fatigue when reading the output image.

Claims (6)

Base film; A protective layer formed on one surface of the substrate; And a non-transfer layer and a transfer layer sequentially formed on the other side of the substrate, the thermal transfer recording medium comprising: And the non-transfer layer comprises a conductive carbon black, a diaryl phthalate resin, and a thermoplastic resin. The thermal transfer recording medium according to claim 1, wherein the content of the diaryl phthalate resin is 20 to 60% by weight based on the conductive carbon black. The thermal transfer recording medium according to claim 1, wherein the thermoplastic resin has a content of 20 to 80 wt% based on the conductive carbon black. The method of claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of nitrocellulose, polyester resin, polyurethane, polystyrene, vinyl chloride-vinylacetate copolymer, acrylic resin, nylon resin and polyvinyl butyral resin Characterized in that the thermal transfer recording medium. 2. The thermal transfer recording medium according to claim 1, wherein the protective layer, the non-transfer layer, and the transfer layer have a surface resistance of 10 ⁵ cm 3 or less. The thermal transfer recording medium according to claim 1, wherein the thickness of the non-transfer layer is 0.2 to 3 μm.