JP2521885B2 - Thermal transfer sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to improvements in heat-sensitive transfer sheets.

[0002]

2. Description of the Related Art In recent years, a thermal recording method using a thermal head has been widely used because of its advantages such as no noise, relatively inexpensive and compact apparatus, and excellent maintainability. There is. As one of the technologies of the heat-sensitive recording, heat-sensitive transfer which does not cause secondary color development due to heat or organic solvent and is excellent in storage stability of recorded matter, that is,
There is a method in which a heat-sensitive transfer sheet having a transfer ink layer which is melted by heating is provided on a base film and the transfer ink is transferred onto a paper surface by using a thermal head.

Conventionally, paper such as condenser paper has been used as a base film of a heat-sensitive transfer sheet. Since such a thin paper has low strength and is particularly vulnerable to tearing, it is desirable to use a tough plastic film such as a polyester resin as a base material, but it is not actually used. This is because a so-called sticking problem, in which high heat of about 300 ° C. is applied to the heat-sensitive transfer sheet on the thermal head during printing and the plastic is fused to the head, easily occurs.

As a measure for enabling the use of a plastic film as a base material for a heat-sensitive transfer sheet, a metal layer is formed by vapor deposition (see Japanese Patent Laid-Open No. 54-143152), and a heat-resistant protective layer of thermosetting resin is used. It has been proposed to provide (see JP-A-55-7467) or to use a supercooling substance as a lubricant (see JP-A-55-146790). However, vapor deposition of metal must be carried out by a batch process, and the cost is inevitable, and if it is thick enough to prevent sticking, the resolution will be affected. The use of a protective layer of thermosetting resin also requires curing, which complicates the manufacturing process and makes the supercooling substance toxic,
There are problems such as odor and corrosiveness to the head.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves such problems and provides a heat-sensitive transfer sheet which prevents sticking and which has a plastic film as a base material and a protective layer formed by simple coating. With the goal.

[0006]

According to the present invention, the object is to provide a heat-sensitive transfer sheet having a transfer ink layer which is melted by heating on one surface of a base material of a plastic film, wherein the other surface of the base material is heated. Plastic resin binder 10
A substance selected from waxes such as polyethylene wax and paraffin wax, amides or esters of higher fatty acids, higher alcohols and phosphates, and acting as a lubricant or a release agent when melted by heating, relative to 0 parts by weight. Is provided in an amount of 10 to 100 parts by weight, and a protective layer made of a composition is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to preferred embodiments. In the present invention, the plastic film to be used as the substrate is optional, but typical ones include polypropylene, cellophane, cellulose acetate and the like in addition to the above polyester resin. A suitable thickness is within 10 μm, and a thin one such as 6 μm can be used.

The ink layer which is melted and transferred by heating uses waxes having an appropriate melting point, such as paraffin wax, microcrystalline wax, carnauba wax, etc. as a binder, and carbon black, various dyes, pigments, etc. The colorant is added.
Its manufacture and application on a substrate film can be carried out according to known techniques.

The thermoplastic resin binder forming the protective layer, which is a feature of the present invention, can be selected from a wide range, but preferred examples are acrylic resin, polyester resin, cellulose acetate propionate, and cellulose acetate. Butyrate, cellulose acetate, vinylidene fluoride resin, nylon, polyvinylcarbazole, chlorinated rubber, cyclized rubber and polyvinyl alcohol. It has been empirically known that these resins preferably have a glass transition point of 60 ° C. or higher.

Examples of the substance mixed with the above-mentioned thermoplastic resin and having a function as a lubricant or a heat release agent when melted by heating are waxes such as polyethylene wax and paraffin wax, amides and esters of higher fatty acids. Or salts, higher alcohols and phosphoric acid esters such as lecithin. In addition to these lubricants or thermal release agents, other release agents, for example, powder of fluorine-containing resin, powder of guanamine resin and wood powder can be used in combination, and in this case, further High effect can be obtained.

The composition for forming the protective layer is formed by blending 100 parts by weight of the thermoplastic resin binder with 10 to 100 parts by weight of the substance acting as a lubricant or a thermal release agent. . The application to the base film may be carried out by kneading with an appropriate solvent to give an ink, applying it by gravure coating, roll coating or any other method, and drying. If it is desired to ensure the adhesion of the protective layer on the substrate film, it is preferable to previously provide a primer layer on the substrate. The primer layer should be selected according to the material of the base film and the type of the thermoplastic resin binder of the protective layer, and is an acrylic resin, a polyester resin, a polyvinyl acetate resin, a vinyl chloride-vinyl acetate copolymer or a polyol. Among the / isocyanate, epoxy / isocyanate, polyol / melamine combinations and the like, suitable materials may be found. The application of the primer may be carried out by an arbitrary method in the form of ink using an appropriate solvent, as in the case of applying the composition of the protective layer.

[0012]

EXAMPLES The present invention will be further described with reference to Examples and Comparative Examples.
This will be described in detail. Example 1 12μm and 6μm 2 thickness polyester film
Using a glass (made by Toray) as a base material
Apply the primer ink of the above formulation by the gravure coating method.
1g / m² It was applied to the thickness (when dried).Primer ink composition: -Polyester resin ("Byron 200", manufactured by Toyobo) 3 parts by weight-Vinyl chloride vinyl acetate copolymer ("Vinylite VAGH", manufactured by UCC) 3 parts by weight-Isocyanate ("Takenate D-110N", manufactured by Takeda Pharmaceutical Co., Ltd.) 1 Parts by weight Toluene / MEK (1/1) 40 parts by weight On top of that, a protective layer ink I having the following composition is also added.
1g / m by via coating method² Applied to the thickness of
Was.Protective layer ink I composition: -Cellulose acetate propionate ("CAP482-05", manufactured by Kodak) 10 parts by weight-Lecithin 4 parts by weight-Toluene / MEK / IPA (1/1/1) 66 parts by weight Next, a thermal transfer ink having the following composition is used. Use a blade kneader
Prepare by kneading for 6 hours while heating to 80 ° C.
On the other side of the film, hot melt heated to 100 ° C
Apply a roll coat to a thickness of 5 μm.
The cloth was used as a heat-sensitive transfer sheet of the present invention.Thermal transfer ink composition: Paraffin wax 10 parts by weight Carnauba wax 10 parts by weight Polybutene ("VH-100", made by Nippon Oil Co., Ltd.) 1 part by weight ・ Carbon black ("Seast S", made by Tokai Electrode) 2 parts by weight

Example 2 The same polyester film as used in Example 1 was subjected to the above-mentioned primer treatment, and subsequently 1 g of a protective layer ink II having the following composition was also prepared by the gravure coating method.
/ M ² was applied. Protective layer ink II composition: -Acrylic resin ("Dianal BR88", manufactured by Mitsubishi Rayon) 10 parts by weight-Polyethylene wax ("Mark FC113", manufactured by Asahi Denka, 30% by weight toluene dispersion) 4 parts by weight-Fluorine resin powder ("MOLD WIZ F-57", manufactured by Toyo Soda Co., Ltd., 50% by weight toluene dispersion) 3 parts by weight Toluene 90 parts by weight Also in this case, the same thermal transfer ink as in Example 1 was used to prepare a thermal transfer sheet of the present invention.

[0014] Polyester film of the two thicknesses of Comparative Example 12μm and 6 [mu] m, without providing the protective layer of the present invention to prepare a thermal transfer sheet of Comparative example given only the thermal transfer ink layer.

Practical test The thermal transfer sheets of the above-mentioned examples and comparative examples were made into ribbons and run on a printer having a thin film type thermal head, and printing energy was 1 mJ / dot (4 × 10 ⁻⁴ c).
Thermal recording was performed under the condition of m ² ) using fine paper (135 g of “KYP”, manufactured by Sanyo Kokusaku Pulp) as a transfer body. As a result, in the heat-sensitive transfer sheets of Examples 1 and 2 according to the present invention, good printing could be performed without the occurrence of sticking, regardless of whether the base film had a thickness of 12 μm or 6 μm. On the other hand, all the products of the comparative examples having no protective layer suffered from sticking, and the base film 1
The 2 μm one also had some holes, and the 6 μm one had significant perforation and rupture.

[0016]

As described above, according to the present invention, a thermal transfer sheet having a plastic film as a base material, which is mechanically tough, but does not cause sticking to a thermal head can be formed by a relatively simple process, Offered at low cost. This heat-sensitive transfer sheet can be widely used in heat-sensitive printers of various recording devices, such as facsimiles. Furthermore, if desired, it is easy to form a ribbon to form a cartridge.

Front page continuation (72) Inventor Kyohei Takahashi 4-11-2-112 Minamidai, Sagamihara City, Kanagawa Prefecture (56) Reference JP-A-57-129789 (JP, A) JP-A-55-7467 (JP, A) JP-A-55-146790 (JP, A)

Claims (4)

(57) [Claims]
1. 1. A heat-sensitive transfer sheet having a transfer ink layer which is melted by heating on one surface of a base material of a plastic film, wherein polyethylene wax is added to the other surface of the base material with respect to 100 parts by weight of a thermoplastic resin binder. , Waxes such as paraffin wax, amides or esters of higher fatty acids, higher alcohols and phosphoric acid esters, and the proportion of the substance which acts as a lubricant or a releasing agent when melted by heating in a proportion of 10 to 100 parts by weight. A heat-sensitive transfer sheet, which is provided with a protective layer made of the composition blended in (1).
2. 2. The heat-sensitive transfer sheet according to claim 1, wherein a polyester resin, polypropylene, cellophane or cellulose acetate is used as the base plastic.
3. 3. A thermoplastic resin binder forming a protective layer composition, an acrylic resin, a polyester resin,
   Cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate, vinylidene fluoride resin, nylon, polyvinylcarbal, chlorinated rubber, cyclized rubber and polyvinyl alcohol selected from those having a glass transition point of 60 ° C. or higher are used. The heat-sensitive transfer sheet according to claim 1.
4. 4. The heat-sensitive transfer sheet according to claim 1, wherein the protective layer is provided on a base material coated with a primer.