JP2599674B2 - Heat-sensitive transfer recording 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 heat-sensitive transfer recording sheet, and more particularly to forming a high-quality image having good printing heat sensitivity and excellent abrasion resistance, heat resistance and solvent resistance. The purpose of the present invention is to provide a heat-sensitive transfer recording sheet capable of performing the following.

[0002]

2. Description of the Related Art Conventionally, in order to improve the abrasion resistance, heat resistance, solvent resistance, etc. of a printed image formed by a heat-sensitive transfer recording sheet, a thermoplastic resin is generally used in a hot-melt transfer layer. However, by using this, the adhesive strength of the thermoplastic transfer layer to the heat-resistant support becomes strong, and the heat transfer becomes difficult or the heat sensitivity is deteriorated. There is a problem that an image cannot be obtained. Accordingly, an object of the present invention is to provide a heat-sensitive transfer recording sheet which has good print heat sensitivity and can form a high-quality image having excellent scratch resistance, heat resistance, solvent resistance and the like. .

[0003]

The above object is achieved by the present invention described below. That is, the present invention provides a heat-resistant support having a low molecular weight styrene resin having a molecular weight of 800 or less, an ethylene-vinyl acetate copolymer and a softening point of 90 ° C. or more.
A heat-sensitive transfer recording sheet comprising: a release layer containing a lubricant having a proportion of at least 50% by weight as a main component; and a heat-softening resin layer provided on the release layer.

[0004]

[Function] By providing a release layer mainly composed of a styrene resin having a relatively low molecular weight, an ethylene-vinyl acetate copolymer and a lubricant on a heat-resistant support, the printing has high heat sensitivity and abrasion resistance. And a heat-sensitive transfer recording sheet capable of forming a high-quality image having excellent heat resistance and solvent resistance.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention is described in more detail with reference to preferred embodiments. In the heat-sensitive transfer recording sheet of the present invention, the weight ratio of the low molecular weight styrene resin, the ethylene-vinyl acetate copolymer, and the lubricant as the main components of the release layer is preferably 1 to 50: 1 to 20:30 to 98. The weight ratio of styrene resin to ethylene-vinyl acetate copolymer is 1
%, The adhesive strength to the heat-resistant support becomes poor.

If the styrene resin content exceeds 50%, or if the ethylene-vinyl acetate copolymer content exceeds 20%, the transferability deteriorates. On the other hand, if the molecular weight of the styrene resin exceeds 800, the compatibility with the ethylene-vinyl acetate copolymer deteriorates, and the transferability also deteriorates. When the amount of the lubricant is less than 30% by weight, the adhesiveness to the heat-resistant support is too good, so that the heat-softening resin layer is hardly peeled off and the transferability is also deteriorated. The lubricant used may be used alone or as a mixture of two or more kinds. When the lubricant having a softening point of 90 ° C. or more is less than 50% by weight, the difference in the melting temperature between the upper layer and the heat-softening resin layer is increased. The transferability is greatly deteriorated.

[0007] Lubricants include carnauba wax, montan wax, candelilla wax, rice wax, microcrystalline wax, sasol wax, paraffin wax, polyethylene wax, oxidized polystyrene, a mixture of polyethylene wax and ethylene tetrafluoride, and a mixture of polyethylene oxide and polyethylene oxide. Finely divided materials such as a fluorinated ethylene resin mixture, a tetrafluoroethylene resin, a fatty acid ester of sorbitan, and a polyamide wax can be used.

These lubricants have the effect of reducing the frictional resistance of a printed image, improve the abrasion resistance, and at the same time, reduce the peeling strength at the time of printing peeling to facilitate the transfer of the transfer layer. It is possible to form a high-quality printed image with good layer and dot reproducibility. Further, as components other than the main component of the release layer, pigments, dyes, extender pigments, metal powders, oils and the like generally used in heat-sensitive transfer recording media are added to such an extent that transferability and scratch resistance are not impaired. I don't mind.

The softening resin layer used in the present invention comprises generally known coloring agents such as organic and inorganic pigments, metal powders and dyes, and polyamide, acrylic, styrene, polyester, vinyl chloride and polyurethane. Resin, epoxy-based, ethylene-vinyl acetate copolymer, ethylene-acrylic copolymer, butyral-based, cellulose-based, petroleum-based, rosin-based, terpene-based resin and carnauba wax, montan wax, candelilla wax, rice wax ,
Micro Crystal Wax, Sasol Wax, Paraffin Wax, Polyethylene Wax, Polyethylene Oxide, Polyethylene Wax and Polytetrafluoroethylene Resin Mixture, Polyethylene Oxide and Polytetrafluoroethylene Resin Mixture, Polytetrafluoroethylene Resin, Fatty Acid Esters of Sorbitan, Polyamide Waxes and other waxes as the main component, other calcium carbonate, barium sulfate,
Extenders such as aluminum oxide, clay, kaolin, clay and silica, oils, plasticizers and the like may be added to the extent that transferability and scratch resistance are not impaired.

The coating of the release layer and the thermosoftening resin layer in the heat-sensitive transfer recording sheet of the present invention is performed by a conventionally known coating method in a state where each component is dissolved or dispersed in a solvent or dispersed in water. . For example, the coating amount after coating and drying is 0.1 to 3 g / m ² , preferably 0.2 to ² g for the release layer.
/ M ² , and the softening resin layer has a thickness of 0.3 to 6 g / m ² , preferably 0.5 to 5 g / m ² .

As the heat-resistant support used in the present invention, conventionally known films and papers can be used. For example, plastic films having relatively high heat resistance, such as polyester, polycarbonate, nylon, polyimide, and triacetyl cellulose, cellophane or parchment paper, condenser paper, and the like can be suitably used.
The thickness of the heat-resistant support is preferably about 2 to 15 μm in consideration of a thermal head as a heat source during thermal transfer.
For example, there is no particular limitation when using a heat source capable of selectively heating a heat-sensitive transfer ink layer such as a laser beam.

When a thermal head is used, a silicone resin, a fluorine resin, a polyimide resin, an epoxy resin, a phenoxy resin, a phenol resin, a melamine resin, By providing a heat-resistant protective layer made of such as above, the heat resistance of the heat-resistant support can be further improved, and printing can be performed more smoothly. The heat-resistant support is not limited to the above-mentioned ones, and any printable one can be used. Further, the heat-resistant protective layer is not limited to the above-mentioned one, and can be used if printing can be performed smoothly.

[0013]

Next, the present invention will be described more specifically with reference to examples. In the following, “parts” means “parts by weight”. Example 1 Release layer polyethylene wax 15 parts Carnauba wax 5 parts Styrene resin (Mw = 350) 3 parts Ethylene-vinyl acetate copolymer (VA = 46) 2 parts Toluene 50 parts MEK 25 parts

The coating liquid for a release layer having the above composition is dispersed in a ball mill for 15 hours, and applied to one side of a 5.7 μm-thick polyester film by a commonly used coating method. The release layer was provided so as to have a thickness of 0.8 g / m ² . Thermosoftening resin layer carbon black 8 parts Polyethylene wax 5 parts Polyester resin 20 parts Toluene 37 parts MEK 30 parts

The coating liquid for a thermosoftening resin layer having the above composition is dispersed in a ball mill for 15 hours, applied on the release layer by a commonly used coating method, and coated in an amount of 2.4 g after drying. / M ² was provided with a thermosoftening resin layer.
A heat-resistant protective liquid made of a silicone resin was applied to the back surface coated with the heat-softening resin layer so that the applied amount after drying was 0.1 g / m ² , thereby providing a heat-resistant protective layer. This step may be performed before applying the release layer and the thermosoftening resin layer. When a barcode was printed on a 100 μm-thick polyester sheet using the obtained heat-sensitive transfer recording sheet of the present invention, a high-quality image capable of reading the barcode was obtained. Even if this printed sheet was subjected to a reciprocating test 100 times with a load of 200 g using a friction tester (manufactured by Suga Test Instruments Co., Ltd.), no change was observed in the printed portion.

Example 2 Release layer polyethylene wax 20 parts Styrene resin (Mw = 400) 2 parts Ethylene-vinyl acetate copolymer (VA = 28) 2 parts Toluene 50 parts MEK 26 parts

The coating solution for a release layer having the above composition was dispersed in a ball mill for 15 hours, and applied to one side of a 5.7 μm-thick polyester film by a commonly used coating method. The release layer was provided so as to be 0.6 g / m ² . Thermosoftening resin layer carbon black 8 parts Polyethylene wax 5 parts Acrylic resin 10 parts Vinyl chloride-vinyl acetate copolymer 10 parts Toluene 37 parts MEK 30 parts

The coating composition for a heat-softening resin layer having the above composition is dispersed in a ball mill for 15 hours, applied on the release layer by a commonly used coating method, and applied in an amount of 1.5 g after drying. / M ² was provided with a thermosoftening resin layer.
As in Example 1, a heat-resistant protective layer was provided to obtain a heat-sensitive transfer recording sheet of the present invention. When a barcode was printed on a polyester sheet having a thickness of 100 μm using the obtained heat-sensitive transfer recording sheet, a high-quality image capable of reading the barcode was obtained. Even if this printed sheet was subjected to a reciprocating test 50 times with a load of 200 g while heating to 150 ° C. using a friction tester (manufactured by Suga Test Instruments Co., Ltd.), no change was observed in the printed portion. When the print sheet was subjected to a rubbing test of 100 reciprocations with a cloth containing ethanol, no change was observed in the printed portion. Further, the same test was performed with gasoline, but no change was observed in the printed portion.

[0019]

As is clear from the above description, according to the heat-sensitive transfer recording sheet of the present invention, a high-quality image excellent in printing heat sensitivity and excellent in scratch resistance, heat resistance, solvent resistance and the like is obtained. Can be formed.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-78692 (JP, A) JP-A-63-162287 (JP, A) JP-A-3-274186 (JP, A) JP-A-3- 38383 (JP, A) JP-A-6-199060 (JP, A) JP-A-60-102959 (JP, U)

Claims (3)

(57) [Claims] A low-molecular-weight styrene resin having a molecular weight of 800 or less, an ethylene-vinyl acetate copolymer, and a resin having a softening point of 90 ° C. or more have a proportion of at least 50 on a heat-resistant support.
A heat-sensitive transfer recording sheet, comprising: a release layer mainly composed of a lubricant in an amount of% , and a heat-softening resin layer provided on the release layer. 2. The release layer according to claim 1, wherein said low-molecular-weight styrene resin
~ 50 parts by weight, ethylene-vinyl acetate copolymer 1-20
The heat-sensitive transfer recording sheet according to claim 1, comprising 30 parts to 98 parts by weight of a lubricant. 3. The heat-sensitive transfer recording sheet according to claim 1, wherein the heat-softening resin layer mainly comprises a colorant, a resin and a wax.