JPS63115790A - Thernal transfer sheet - Google Patents

Abstract

PURPOSE:To enhance feedability and prevent an ink layer surface from being curled, by providing a thermal transfer layer on one side of a base and providing a silicone-modified electron ray curable resin on the other side to produce a thermal transfer sheet. CONSTITUTION:A thermal transfer layer comprising a heat-fusible ink is provided on one side of a plastic film constituting a base, by hot-melt coating. Next, a coating material comprising a silicone-modified electron ray curable resin as a main constituent is applied to the other side of the plastic film, is dried, and is then hardened by the irradiation with electron rays to provide a heat-resistant slip layer, thereby obtaining a thermal transfer sheet. The silicone-modified electron ray curable resin is represented by formula I, wherein R' is -(CH2)n-(wherein n is 0-2), TDI is 2,4-tolylene diisocyanate, HEM is 2- hydroxyethyl acrylate, X its 30-100, and Y is 2-6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive transfer sheet having a heat-sensitive transfer layer on one side of a base material and a heat-resistant slip layer on the other side.

[Prior art] In recent years, a heat-melting ink layer containing a pigment or dye, a sublimable ink layer containing a sublimable dye in a binder, or a heat-reactive coloring component has been developed on a base material such as a plastic film. Using a heat-sensitive transfer sheet with a heat-sensitive transfer layer,
A widely used method is to perform thermal printing according to image information using a heating means such as a thermal head to form an image on a receiving sheet.

Conventionally, plastic films such as polyester films, polyimide films, polypropylene films, aromatic polyamide films, cellulose acetate films, and cellophane films with a thickness of 2 to 15 μm have been used as substrates for such heat-sensitive transfer sheets. Among these, polyester film is preferably used because it is easy to form a uniform thickness, has excellent surface smoothness, and is easy to operate in a printer.

However, thermal transfer sheets using this polyester film as a base material require high energy to obtain a sufficient printing temperature, so a so-called sticking phenomenon occurs in which the polyester itself fuses with the thermal head. In addition, to maintain the thermal head pressure and the heat-sensitive transfer sheet, the bat pressure in the cassette or the contact resistance with the roll in the printer cause poor running performance, resulting in irregular printing density, background smearing, etc. In severe cases, the base material may break.

In order to prevent these phenomena, for example, a method of providing a metal oxide layer or an anti-friction layer made of silicon oxide on the base material (Japanese Patent Laid-Open No. 54-143152@, JP-A No. 57-74195), silicone resin, etc. A method of providing a heat-resistant resin layer such as or epoxy resin (Japanese Unexamined Patent Publication No. 7467/1982), a method of providing a resin layer containing a solid or semi-solid surfactant at room temperature (Japanese Unexamined Patent Publication No. 129789/1982) Alternatively, a method of providing a heat-sensitive resin layer containing a lubricating inorganic pigment (Japanese Patent Application Laid-open No. 5
6-155794) etc. have been proposed.

However, these methods require expensive processes such as vapor deposition, use a large amount of thermal energy for thermal curing, and require long periods of time to provide sufficient heat resistance. It requires aging, has insufficient lubricity, and often has the disadvantage that dirt adheres to the thermal head.

Furthermore, since the heat-sensitive transfer sheet used in the above conventional method is generally stored rolled up, the heat-resistant layer and the transfer layer come into contact with each other during storage, resulting in a blocking phenomenon, which causes background smudges and image fading when printed. There was a problem that occurred.

In addition, the method of using a wax that melts with the heat from the thermal head and exhibits lubricity as a lubricant, such as the method of JP-A-58-187396, may cause sticking phenomenon or failure of the thermal transfer sheet to feed when heat is absorbed. There was a drawback that problems such as the following occurred.

The structure of the present invention for achieving the above object is that in a heat-sensitive transfer sheet having a heat-sensitive transfer layer on one side of a base material and a heat-resistant slip layer on the other side of the base material, the main component of the heat-resistant slip layer is silicone. This is a heat-sensitive transfer sheet made of modified electron beam curable resin.

The present invention will be explained in more detail below. The silicone-modified electron beam curable resin used in the present invention is represented by the following general formula.

(However, in the above formula, Ro is +CH2+, (n is O~2), TDI is 2.4-)-lylene diisocyanate, HEM is 2-hydroxyethyl acrylate, X = 50 to 100 V = 3 to 6 It is. ) This silicone-modified electron beam curable resin has excellent film properties and can form a uniform and thin film.
Furthermore, since it has a silicone functional group, it has an excellent slip effect. Further, it is desirable to use a polyfunctional electron beam curable monomer in combination in order to provide a heat-resistant effect.

This 7-mer acts as a crosslinking accelerator for the silicone-modified electron beam curable resin, and is advantageous in forming a complex and high-density crosslinked structure.

Specific examples of such monomers include trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, dipentaerythritol hexatriacrylate-1
・etc.

It is preferable to add 20 to 501 m parts of the above-mentioned hexamer based on 1001 m parts of the silicone-modified electron beam curable binder. Below this lower limit, the crosslinking effect decreases and the heat resistance effect decreases.

Moreover, if the upper limit is exceeded, the lubrication effect on the surface will be reduced and the slip effect will be reduced.

The film layer of the heat-resistant slip layer of the present invention varies depending on the feedability of the printer, applied energy, etc., but is usually 0.05
It is appropriate that the thickness be 5 μm, preferably 0.1 to 2 μm.

As the plastic film used as the base material in the present invention, those formed from various conventionally known thermoplastic resins can be used, such as polyester film, polyamide film, polyolefin film,
Examples include polycarbonate films and cellulose films, and the thickness thereof is usually about 0.5 to 50 μm, preferably about 3 to 110 μm.

To actually produce the heat-sensitive transfer sheet of the present invention, a coating material whose main component is a silicone-modified electron beam curable resin is applied onto a substrate, dried, and then cured by electron beam irradiation to form a layer.

Electron beam irradiation during layer formation is performed at an accelerating voltage of 100 to 750 kv.
It is carried out using an electron beam accelerator at 150 to 300 kV (D) so that the absorbed dose is 2 to 20 M rad.Also, the solvents used to prepare the paint for each layer include acetone and methyl ethyl ketone. , cyclohexane, ethyl acetate, toluene, xylene, hexane, heptane and the like.

In the present invention, the type of the heat-sensitive transfer layer to be formed on the base material is not limited, and a non-reactive type or a reactive type can be arbitrarily used. Examples of transfer layers include a transfer layer made of a meltable ink or a transfer layer made of a sublimable dye. Examples of reactive type transfer layers include a transfer layer containing one of the reactive components of a color-forming reaction system in the following combinations. layers can be mentioned.

(1) Combination of leuco dye and color developer (electron-accepting substance).

(2) Combinations of long-chain aliphatic iron salts such as ferric stearate and ferric myristate with phenols such as tannic acid, gallic acid, and ammonium salicylate.

(3) Combinations of monometallic sulfates such as silver, lead, mercury, and thorium sulfates with sulfur compounds such as Na-tetrathionate, sodium thiosulfate, and thiourea.

(4) Combinations of organic acid salts such as silver behenate and silver stearate with aromatic organic reducing agents such as protocatechuic acid, spiroindane, and hydroquinone.

(5) Combinations of organic acid lead salts such as lead caproate, lead pelargonate, and lead behenate with thiourea derivatives such as ethylenethiourea and N-dodecylthiourea.

When using a heat-sensitive transfer sheet having a reactive heat transfer layer as described above, the receiving sheet receiving the transfer is as follows:
A sheet having a receptor layer containing a reactive component that causes color development by reacting with a reactive component contained in a thermal transfer layer of a color-forming reaction system consisting of the combination described above is used. For example, when the thermal transfer layer contains a leuco dye, a receiving sheet containing a color developer such as a phenolic substance can be used as the receiving sheet.

Further, the color-forming reaction system consisting of a combination of the two types of reaction components described above can be contained in the thermal transfer layer in a state in which the color-forming reaction is necessarily prevented in advance. A heat-sensitive transfer sheet having a transfer layer containing such a color-forming reaction component can transfer an image consisting of a molten deposit of a color-forming reaction product onto a paper serving as a receiving sheet by thermal transfer.

In addition, to explain the formation method for an example having a non-reactive heat-sensitive transfer layer, a composition consisting of a colorant, a binder agent, etc. is hot-melt coated on a film base material, or the composition is dispersed in an appropriate solvent. The coating solution can be solvent coated to form a layer of about 1 to 20 μm. As the colorant, any conventional pigment such as carbon black can be used, and as the binder, waxes such as carnauba wax, book wax, and beeswax can be used.

Next, the present invention will be explained in more detail with reference to Examples.

It should be noted that all parts of each component described in the Examples are heavy parts.

Example 1 Composition of silicone-modified electron beam curable resin Silicone-modified urethane acrylate (manufactured by Freeman, USA, 19-4842) 5 parts Polyfunctional monomer (manufactured by Toagosei Kagaku Kogyo Co., Ltd., H-8030) 2 parts Methyl ethyl ketone-toluene mixed solvent (Yowa ratio approx. 1
: 1) A resin solution consisting of 100 parts was prepared.

A coating solution of the above composition was applied onto a 3.5 μm polyethylene terephthalate film using a wire bar so that the film thickness after drying would be 1.0 μm, and after drying, it was irradiated with an electron beam to form a layer.

Next, a hot-melt ink coating liquid having the following composition was prepared.

Carbon black 1580 parts Paraffin wax 155''F 33.0 parts Carnauba wax No. 1 25.0 parts Polyethylene wax (Sunwax E-250P manufactured by Sanyo Chemical Co., Ltd.) 25.0 parts Mineral oil
2.0 parts of the coating solution having the above composition was hot-melt coated to form an ink layer of 4.5 μm thick on the side opposite to the heat-resistant slip layer, and a heat-sensitive transfer sheet was prepared.

Comparative Example 1 A heat-sensitive transfer sheet was obtained in exactly the same manner as in Example 1, except that the heat-resistant slip layer forming liquid was changed to the following composition.

Room temperature self-condensing silicone rubber (TSE-397, manufactured by Toshiba Silicone) 5 parts Toluene 100 parts Test and results 60: Type 6
200 (manufactured by Ricoh)] so that the ink surface was in contact with the ink surface, and printed using a thermal head from the heat-resistant slip layer under printing conditions of a head pressure of 0.4 W, a pulse width of 5 to 10 m5 eC, and a dot density of 6 dots/mm. did. The thermal transfer sheet of Example 1 was smoothly fed within the printer and the cassette, and no sticking phenomenon occurred under the thermal energy condition of the thermal head of 0.8 mJ/dot or less. Furthermore, no wrinkles were observed in the solid areas treated with ink, and there was no background smearing of the printed image due to feeding, no disturbance of the image due to sticks, and no curling of the ink layer.

On the other hand, the thermal transfer sheet of Comparative Example 1 had poor feeding performance in the printer and cassette, and a sticking phenomenon occurred when the thermal energy condition of the thermal head was 0.8 mJ/dot or less, resulting in disordered printed images. Or, there was noticeable dirt on the surface.

[Effects] As explained above, the heat-sensitive transfer sheet of the present invention has the following advantages because it has a heat-resistant slip layer mainly composed of a silicone-modified electron beam curable resin on one side of the base material. is.

(1) It is stable against the thermal energy of the thermal head and does not cause sticking, so it has stable feeding performance.

(2) The cassette material in the printer has good lubricity when in contact with the roll, and does not cause background smudges or image disturbances in printed images.

(3) Even if the ink layer contains a highly heat-shrinkable compound, curling of the ink layer can be prevented.

Patent applicant Ricoh Co., Ltd. - Agent Patent attorney Hidetake Komatsu Agent Patent attorney Hiroshi Asahi Procedural amendment (gi) November 6, 1985 1, Indication of case Patent filed November 4, 1986 Application 2, Title of Invention: Heat-sensitive transfer sheeting, same as above, -25,
Date of amendment order (voluntary) 6. Scope of claims and detailed explanation of the invention in the specification to be amended, column 7, Contents of amendment (attached sheet) (1) The scope of claims has been amended as follows: do.

"A heat-sensitive transfer sheet having a heat-sensitive transfer layer in the order of the base material and a heat-resistant slip layer on the other side of the base material, characterized in that the main component of the heat-resistant slip layer is a silicone-modified electron beam curable resin. (2) Insert the following sentence between lines 14 and 15 on page 4 of the same document.

[[Objective] In order to solve the above-mentioned problems of the prior art, the present invention provides an inkjet ink layer that is stable against thermal energy of a thermal head during printing, exhibits excellent feeding performance, and prevents curling of the ink layer surface. The purpose of the present invention is to provide a heat-sensitive transfer sheet that can prevent

[composition] "

Claims (1)

[Claims] A heat-sensitive transfer sheet having a heat-sensitive transfer layer on the interface of the base material and a heat-resistant slip layer on the other side of the base material, characterized in that the main component of the heat-resistant slip layer is a silicone-modified electron beam curable resin. Thermal transfer sheet.