JPS5996992A - Thermal transfer ink sheet - Google Patents

Abstract

PURPOSE:To provide an ink sheet which enables a frequent thermal print transfer using the same thermal transfer sheet by interposing an adhesive layer made of a filamentous saturated polyester between a support and an ink layer. CONSTITUTION:In a hot melting ink layer provided on a support, a thermal transfer ink sheet is arranged by interposing an adhesive layer made of a filamentous saturated polyester (e.g. those such as formed by a polycondensation reaction between ethylene glycohol and adipic acid so as to bond main chain atoms in a chain) between the support (e.g. condenser paper and polyester film) and the ink layer (e.g. a hot melting matter comprising a colorant such as carbon black, resin such as PVC, a hot melting material such as various waxes and a solvent such as toluene). The interposition of the adhesive layer eliminates separation of the whole ink layer off the support to transfer onto a paper to be transferred thereby enabling a frequent thermal print transfer using the same thermal transfer sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to thermal transfer inks for multiple applications.

[Prior art]

Conventional thermal transfer ink sheets are one-time application type.
By multiple transfers, all of the ink in the transfer portion on the sheet is transferred to the receiving paper. Examples of such thermal transfer ink sheets include those in which a release layer is provided between the sheet and the ink layer (Japanese Unexamined Patent Publication No. 144751/1983), and those in which ink layers are provided on both sides of the support. (Unexamined Japanese Patent Publication No. 56-981
No. 78) and the like are known.

In order to make the thermal transfer ink sheet as described above applicable not only to one-time use but also to multiple transfers, the ink transferred from the transfer sheet to the receiving paper at the time of transfer must be It is necessary to limit the portion to a part of the ink layer on the transfer sheet, but not to the entire ink layer.
None of the methods proposed so far are suitable for such multiple transfers.

〔the purpose〕

In order to develop a heat-sensitive transfer ink sheet that can be applied to multiple transfers, the inventors created an adhesive layer between the ink layer and the support to increase the adhesive force between the ink layer and the support. I have conducted various research on how to improve it. However, conventional adhesives such as polyvinyl acetate and vinyl acetate/
When using adhesives with low melting points or softening points, such as vinyl chloride copolymers, acrylic resins, or epoxy resins, the ink layer may peel off from the support during heating printing, making it impossible to achieve the intended purpose. It turned out that it wasn't possible. As a result of further intensive research, the present inventor discovered that the objective could be achieved by interposing an adhesive layer made of linear saturated polyester between the support and the ink layer, and developed the present invention. It has been completed.

〔composition〕

That is, according to the present invention, in a product in which a heat-melting ink layer is provided on a support, an adhesive layer made of linear saturated polyester is interposed between the support and the ink layer, and A heat-sensitive transfer ink sheet is provided, which is characterized in that it can be applied.

In the present invention, an adhesive layer made of a linear saturated polyester is interposed between the ink layer and the support, but the linear saturated polyester in this case is a dioxy compound (or alkyleneoxy F) and a dibasic acid. It is formed by a polycondensation reaction with the main chain atoms, and the main chain atoms are linked in a chain.

Regarding this polyester component, dibasic acids include, for example, adipic acid, azelaic acid, henananotic acid, phthalic acid, etc., and dioxy compounds (or alkylene oxides) include ethylene glycol, ethylene oxide, 1,4 - Cyclohexane dimetatool and the like. However, the molecular weight of this polyester is usually 15
,000 to 20,000. In the present invention, commercially available products are used, such as No.zeta.Iron-200 [: Toyobo ■], and .zeta.Iron-300 [Toyobo ■]. In the present invention, the polyester layer formed on the support has an adhesion amount of 0.5. s %/m". In addition, for the purpose of improving heat resistance, solvent resistance, and other properties, nitrified cotton, soluble vinyl chloride, phenol, iso/anate, methoxymelamine,
Plasticizers such as xylene, silicone, epoxy, chlorinated rubber, vinylidene chloride, sucrose benzoate, petroleum resin, polyketone, chlorinated polypropylene, coumaron, triazine formaldehyde, rosin ester, acrisulfonamide, linear urethane elastomer, DMP, DBP, etc. It may be used by mixing and dissolving with.

As the support used in the present invention, conventional supports can be used, but those with high smoothness and thinness are preferably used, such as condenser paper, polyester film, stainless steel sheet, etc.

In the present invention, the ink layer provided on the support may be a heat-melting ink layer, and any conventionally known ink layer may be employed. For example, in the present invention, a colorant, a resin, a heat-fusible substance, and a solvent are used. In this case, the resins include polyvinyl chloride, polyvinyl acetate, polyvinyl fluoride, polyvinyl butyral, polyvinylidene chloride,
Polyvinyl alcohol, vinyl chloride/vinyl acetate copolymer, vinyl chloride/vinylidene chloride copolymer, polyacrylic acid ester, polymethacrylic acid ester, ethyl cellulose, polystyrene, polyethylene, ethylene/vinyl acetate copolymer, polyamide, gelatin, Arabic There are rubber etc. As the coloring agent, conventionally known ones, for example,
In addition to black coloring agents such as Karn Black, triiron tetroxide, and Nigrosin Pace, blue coloring agents such as cyanine sol, oil sol, and alkali blue, iosol red, rose bengal, crystal nono iolet, and brilliant green are used. be done.

Further, as the heat-melting substance, a substance that is solid or semi-solid at room temperature is applied, and examples of the semi-solid substance include lanolin, white petrolatum, hydrophilic petrolatum, hydrogenated vegetable oil, etc. with a viscosity of 100,000 cp or more. There are
Solid substances include various waxes, waxy substances,
Higher fatty acids or their esters and salts, higher fatty acid amides,
Examples include higher alcohols and polyhydric alcohol esters. These substances that are solid or semi-solid at room temperature may be used alone or in the form of a mixture, but it is preferable to use a mixture of a solid substance and a semi-solid substance. The thermofusible substance used in the present invention exhibits a liquid state at 60° C. or higher. When mixing the ink components, a solvent is used, and examples of the solvent in this case include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dichloromethane, dichloroethane, tetrachloroethane, toluene,
Examples include methanol. This solvent is appropriately selected depending on the type of resin to be applied and the type of heat-fusible material, and is selected so as to be soluble in the resin component and soluble or dispersible in the heat-fusible material. , used alone or in the form of a mixture.

In the ink used in the present invention, it is preferable to use a resin component and a hot-melt monolithic substance that are mutually incompatible. The thermofusible substance is incompatible with the resin component. Ink consisting of a resin, a thermofusible substance, and a colorant, which are incompatible with each other, has a microporous structure (sponge structure) in which the colorant and the thermofusible substance are contained in the pores of the resin. The heat-fusible material contained therein forms a solid continuous phase within the pores. When such ink is heated, the ink is not transferred from the ink layer all at once, but is transferred to the transfer paper little by little, and can be transferred to the transfer paper many times. Further, details regarding such ink are shown in Japanese Patent Application Laid-Open No. 1988-68253.

〔effect〕

When the thermal transfer ink 7 of the present invention is placed on a transfer paper and thermally printed, an ink image is formed on the transfer paper, but in this case, there is a line between the ink layer and the support. Since the adhesive layer is made of saturated polyester, the entire ink layer will not peel off from the support and be transferred onto the transfer paper, and can be thermally printed multiple times using the same thermal transfer sheet. Transcription becomes possible.

〔Example〕

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

Example A linear saturated polyester [Byron 200, Toyobo ■] was dissolved in methyl ethyl ketone to obtain a solution with a concentration of 20%, and this solution was applied to a 15 μm thick condenser paper with a dry adhesion amount of 2 P/m”. Next, apply ink with the following composition to the surface of this adhesive,
It was dried to form a multi-ink layer (an ink layer that can be used many times) with a thickness of 12 μm, and a thermal transfer ink cartridge was created.

Vinyl chloride/vinyl acetate copolymer 10 parts by weight Carnano wax 7 Castor wax 11 parts by weight Carbon black
4 Ethyl acetate 51 Toluene 17 The above-mentioned marulink was prepared as follows.

Carbon black, carnauba wax and castor wax are mixed at 80°C and thoroughly kneaded.

Separately, vinyl chloride/vinyl acetate copolymer, ethyl acetate, and toluene were uniformly stirred and mixed at 50°C.
Completely dissolve the copolymer.

Next, the above-mentioned contaminant was uniformly mixed into this copolymer resin solution to obtain an ink.

Comparative Example 1 A thermal transfer ink sheet was obtained in the same manner as in Example except that the ink was applied directly to the capacitor paper.

Comparative Example 2 In the example, acrylic resin [Dianal L-3
96, Mitsubishi Rayon■] was diluted with toluene to a concentration of 20.
A thermal transfer ink sheet was obtained in the same manner, except that a solution of H was prepared and used in place of the linear saturated polyJ ester solution.

Next, the three types of samples obtained above were
0 [■ Made by Ricoh] Thermal transfer was performed. We also conducted a two-fold test on these samples. In this case, in the two-fold test, fold the sample in half with the ink layer inside, and visually judge the adhesion between the ink layer and the support at the folded line. It was marked as defective. The results of the above test are shown in the following table.

Table 1 From the results shown in the above article, thermal transfer ink 7 of the present invention
It can be seen that -gt shows good results.

Since the product of Comparative Example 1 does not have an adhesive layer, the ink layer can be peeled off by folding it in half without applying heat.

In the product of Comparative Example 2, the adhesive layer was made of acrylic resin,
Since the softening point is 48° C., it is adhesive at room temperature, but when printing is heated, that part peels off and is transferred to the transfer paper.

Patent applicant: Ricoh Co., Ltd. Agent Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) A heat-sensitive transfer ink sheet comprising a heat-melting ink layer on a support, characterized in that an adhesive layer made of linear saturated polyester is interposed between the support and the ink layer. .