JPS6056594A - Thermal sensitive transfer recording material - Google Patents

Abstract

PURPOSE:To obtain the titled recording material obtaining a printing image of fixing property and rigidity in combination of heat sensitive thermal transfer recording sheet coated with a heat sensitive coloring layer on one side surface and with gallic acid of specific melting point on the opposite surface and an image receiving sheet coated with Fe salt. CONSTITUTION:A heat sensitive recording material is coated on one side surface of a base material (e.g., sheets of condenser sheet of 10-30mu, resin films of polyester), a gallic acid alkyl ester of 80-160 deg. of melting point is coated on the opposite side surface in a heat sensitive thermal transfer recording sheet is combined with an image receiving sheet coated with Fe salt (e.g., iron stearate). When thermally printed by a heat generating head by setting the melting point of the gallic acid alkyl ester to 80-160 deg.C, a printing image is formed on the heat sensitive coloring layer of the recording sheet is formed, and a clear printing image is obtained also on the image recording sheet.

Description

[Detailed description of the invention] The present invention relates to a thermosensitive thermal transfer recording material.

More specifically, it refers to a heat-sensitive thermal transfer recording material comprising a heat-sensitive coloring layer on one side of a substrate and a gallic acid alkyl ester as a heat transfer recording layer on the opposite side.

In recent years, thermal transfer recording methods have been put into practical use, having advantages over thermal recording methods using thermal recording devices such as thermal printers and thermal facsimiles, such as post-recording storage stability, tamperability, and solvent resistance. . This is called thermal transfer recording paper, and it has a layer of heat-melting ink on a support.The ink layer side is overlapped with plain paper, and the paper is transferred by heat from a thermal head of a thermal facsimile machine, etc., and is used for thermal transfer recording. Recording is performed by transferring ink from paper to plain paper. Single-color thermal transfer recording, such as black, has already been put into practical use.

Furthermore, as a paper capable of recording multiple images, there is a heat-sensitive thermal transfer recording paper in which a heat-sensitive coloring layer is provided on the non-coated surface of the thermal transfer recording paper.

However, thermal transfer recording paper coated with no gold has the following unpleasant drawbacks. That is, although the printed image after printing has the above-mentioned characteristics, it is not firmly fixed to the surface of the plain paper, and has the drawback that the printed image easily peels off or is easily tampered with during handling. For this reason, four different proposals have been made regarding the composition of hot-melt ink.

For example, in Japanese Patent Application Laid-Open No. 55-39380, one side of a base sheet is coated with a disperse dye having a melting point of 60 to 120°C and at a temperature higher than the melting point, or a disperse dye with other colorants added as necessary. We have disclosed a thermal transfer recording paper coated with a transfer layer consisting of a low-molecular substance and a disperse dye that are compatible and permeable to the recording medium.
:#) When thermal printing is performed, the printed image penetrates and is fixed at the same time as it is transferred and recorded on the recording medium.

JP-A No. 55-39381 discloses that the transfer layer of thermal transfer recording paper is made of a resin with a softening temperature range of 60 to 110°C, a disperse dye, or a disperse dye and other colorants, and a liquid state at room temperature or when heated with a thermal head. Compatible with liquid disperse dyes! The invention discloses a material made of a low molecular weight substance that is heated and printed by a thermal head, and the printed image is transferred and recorded onto a recording medium and at the same time penetrates and is fixed.

Furthermore, JP-A-56-109787 describes a thermal transfer ink ribbon, but the thermal transfer ink layer is composed of solid waxes, resins, and, if necessary, oils, all containing sublimable dyes and carbon black. After printing is heated with a thermal head, the sublimable dye in the printed image is sublimated using large thermal energy such as infrared irradiation, penetrates into the recording medium, and is fixed to obtain a solid printed image. That is what it is.

The above-mentioned examples are complex formulations that have been thoroughly considered for the composition of the heat-melting ink itself, and include low-molecular substances, resins, and sublimation dyes that easily permeate into the recording medium, allowing for storage before heating printing. There is a problem with stability.

On the other hand, in heat-sensitive thermal transfer recording paper with the entire heat-sensitive coloring layer coated, the coated surface is colored because the heat-melting ink used as the heat-melting recording layer uses colored dyes or pigments, so there is no back-printing on the surface of the heat-sensitive coloring layer. However, the appearance is unfavorable and the printed image is difficult to distinguish. Therefore, improvements have been made. For example, Japanese Patent Application Laid-Open No. 58-78793 discloses a thermal recording copying paper with a heat-sensitive coloring layer on one side of the base material and a heat-melting ink N gold film on the other side. For the purpose of preventing transfer of colored heat-melting ink, a vapor-deposited layer is provided before a heat-sensitive coloring layer is previously provided for the purpose of preventing transfer. This has the disadvantage that manufacturing is complicated and, furthermore, heat conductivity from the heating head is poor.

The present inventors conducted extensive research to solve these drawbacks, and as a result, the entire heat-sensitive recording layer was coated on one side of the base material, and gallic acid alkyl ester and waxes 7i were coated on the other side.
- In a heat-sensitive heat transfer recording material formed by combining coated heat-sensitive heat transfer recording paper and Fe salt-coated image receiving paper, the melting point of the gallic acid alkyl ester is set to 80 to 160°C, so that a heat-generating head can be used. It has been possible to provide a heat-sensitive thermal transfer recording material that can form a printed image on the heat-sensitive coloring layer of the recording paper and at the same time obtain a clear printed image on the image-receiving paper when thermal printing is performed.

According to the present invention, since the thermal transfer recording layer made of gallic FF fullkyl ester and wax provided on the back side of the base material is a colorless or slightly colored layer, the heat-sensitive color forming layer on the front side is formed throughout the base material. The heat-sensitive coloring layer has the advantage of not requiring any measures to prevent bleed-through.

Moreover, the printed image has the advantage that it can be duplicated on two sheets: one on which the thermosensitive coloring layer is provided and the other on the image-receiving paper.

Furthermore, the printed image thermally printed on the image-receiving paper surface using a heat-generating head is a printed image caused by a chelate reaction between gallic acid alkyl ester and Fe salt, so it has the advantage of being a printed image with good fixability and robustness. be.

Another advantage is that the printed image obtained has thermal stability.

The present invention will be explained in detail below.

The heat-sensitive thermal transfer recording paper according to the present invention has a heat-sensitive color forming layer on one side of the base material, and further coated with a gallic acid alkyl ester dissolved or dispersed in wax on the opposite side of the base material. When heating printing is performed with a heat-generating head on the coated side of the heat-sensitive coloring layer of thermal thermal transfer recording paper by overlapping the coated surfaces of the image-receiving paper fully coated with Fe salt, a printed image is formed on the surface of the heat-sensitive coloring layer. At the same time, a black printed image produced by the chelate reaction of gallic acid alkyl ester and Fe salt can be obtained on the corresponding portion of the coated surface of the image receiving paper.

The melting point of the gallic acid alkyl ester used in the present invention is 80 to 160°C, which is a suitable melting point range for thermal transfer using heat from a heating head.

If the melting point is 160° C. or higher, the response to heat from the heating head will be poor, and if it is below 80° C., the thermal stability will be poor, which is undesirable.

Suitable gallic acid alkyl esters include ethyl gallate, globil gallate, isoamyl gallate, octyl gallate, lauryl gallate, stearyl gallate, and the like.

Regarding the receiving paper, regarding the coated PE salt,
Examples include iron stearate and inorganic salts such as ferrous sulfate, ferric chloride, Mohr's salt, etc., but iron stearate is preferred because it causes less discoloration due to oxidation.

Examples of waxes include paraffin wax, microcrystalline wax, beeswax, spermaceti wax, shellac wax, carnauba wax, candelilla wax,
Montan wax, low molecular weight polyethylene wax, etc. are used.

In addition, additives such as low-melting point resins and softeners may be added to the heat transfer record 81-, and additives such as pigments and binders may be added to the image-receiving paper without any limitation.

The base material of the heat-sensitive thermal transfer recording paper is preferably thin in terms of transfer characteristics, and paper sheets such as 10 to 30 μm capacitor paper and glassine paper, or resin films such as polyester, polyimide, polycarbonate, and Teflon are used.

The base material of the image-receiving paper may be paper such as high-quality paper, or the base material for the heat-sensitive thermal transfer recording paper described above.

The heat-sensitive color forming layer used in the present invention can be those used in general heat-sensitive paper, but specific examples are as follows.

(A) Dye precursor crystal violet lactone, malachite green lactone, 3-diethylamine-7-methylfluoran, 3-diethylamine/-6-methyl-7-chlorofluoran, 3-diethylamine-7-sibenzylaminofluoran , 3-diethylamino-7-anilinofluorane, 3-(N-methylcyclo/)-7-anilinofluorane, 3-diethylamino-7-(m-trinorolomethylanilino)fluorane, 3-diethylamino- 6-Methyl-7-anilinofluorane, 3-(N-methylcyclohexylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane B) Cino 6-methyl-7-anilinofluorane, 3-(N-methyl-P-)luidino)-
6-methyl-7-anilinofluorane, benzo-β-naphthospiropyran, etc.

(B) Color developer phenol, para-tert-butylphenol, paraphenylphenol, α-naphthol, β-naphthol, 4.4'-isoglopylidenediphenol, 4.4
'-5ec-butylidene diphenol, 4,4'-isopropylide/bis-(2-tert-butylphenol), 4,4'-cyclohexylidene diphenol, phenyl-4-hydroxybenzoate, novolac type phenol resin, Salicylic acid, 3-phenylsalicylic acid, 5
-Methylsalicylic acid, 3°5-di-tert-butylsalicylic acid, etc.

(C) Sensitizers stearamide, palmitamide, oleamide, lauric acid amide, ethylene bis stearamide, methylene bis stearamide, methylol stearamide, etc.

(D) Other polyvinyl alcohol, starch, sodium salt or ammonium salt of styrene-maleic anhydride copolymer,
Adhesives such as styrene-butadiene copolymer emulsions. If necessary, pigments such as titanium dioxide, calcium carbonate, kaolin, calcined kaolin, and aluminum hydroxide may be added.

Select an appropriate one from each group of (A), (B), (C), and (IJ) to make an aqueous dispersion, apply it with a coater, and smooth the coated surface with a suit calender to develop heat-sensitive coloring. You get layers.

The method of coating the entire thermal transfer recording layer of the present invention on the opposite side of the substrate on which the heat-sensitive coloring layer is provided is to use a hot-melt printing machine, gravure printing machine, etc. as a heat-melting ink to coat the entire surface or a part of the substrate. This includes printing and coating.

In addition, methods for coating Fe salt on image-receiving paper include coating the entire surface of the substrate using a general coater such as an air knife coater as an aqueous dispersion coating solution, a method using a flexo printing machine,
Examples include a method of printing and coating the entire surface or a portion of the base material using a gravure printing machine or the like.

Hereinafter, the present invention will be fully explained in detail with reference to Examples. Note that "parts" in the examples indicate parts by weight.

Example 1 (1) Preparation of heat-sensitive thermal transfer recording paper Ordinary heat-sensitive coating liquid f26f/n? It is coated on thin glassine paper using an air knife coater, and a black heat-sensitive coloring layer of 8 μm is applied in advance. Next, using lauryl gallate having a melting point of 96 parts as a gallic acid alkyl ester, apply it to the next formulation using a hot melt coating machine so that about 5 is - on the side opposite to the side on which the heat-sensitive coloring layer is provided. A thermosensitive thermal transfer recording paper was prepared by coating.

Lauryl gallate 15 parts Carnauba wax 40 parts Paraffin wax 30 parts Ethylene-vinyl acetate copolymer 15s (2) Preparation of image-receiving paper: Iron stearate as Fe salt was applied to the ball in advance in an amount of about 4 ml. Coated using a Mayer bar.

Iron stearate 25 parts Light carbon 50 parts Polyvinyl alcohol 25 parts (3) Printability test The heat-sensitive thermal transfer recording paper and image receiving paper obtained in (1) and (2) above were stacked to form a heat-sensitive coloring layer of the heat-sensitive heat transfer recording paper. When printed using a facsimile testing machine manufactured by Matsushita Electronic Components, a clear black printed image was obtained on the surface of the heat-sensitive coloring layer and the surface of the receiver paper. Furthermore, the results of the evaluation of transferability, fixability, fastness, and thermal stability on image-receiving paper and the whiteness of the surface of the heat-sensitive coloring layer for the obtained printed images are listed in Table 1.

Examples 2 to 5 Heat-sensitive thermal transfer recording paper was prepared in the same manner using the following gallic acid alkyl ester in place of the conger eel lauryl in (1) of Example 1, and a comparative example was prepared in (2) of Example 1. 1 Printability test tli in the same manner as in Example 1, using methyl gallate having a melting point of 200° C. instead of lauryl gallate according to (1) of Example 1.

Comparative Example 2 A printability test was conducted in the same manner as in Example 1 using commercially available thermal transfer recording paper.

The thermal transfer recording paper used was our company's thermal transfer recording paper (a combination of TTP paper and TTR paper) coated with heat-melting ink.

The results of the printability tests conducted in Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1.

Table 1 In the tests shown in Table 1, transferability is the clarity of the printed image, visibility is Sakata of the printed image when oils and fats are attached, and fastness is when cellophane tape is applied to the printed image and removed. Peeling and thermal stability indicate the stability of the printed image when the printed image-receiving paper is held at 100° C. for 6 hours, and all indicate that the stability worsens in the order of ○, Δ, and ×.

Comparative Example 1 had poor printing performance, and other characteristics were not tested because the test was based on the sharpness of the printed image.

Regarding the set-off of the thermal transfer recording layer, which is a feature of the present invention, the result is shown in the whiteness column of the thermal coloring (- side) in Table 1, but in Examples 1 to 4, there was no shadow on the thermal coloring layer. The color was white without causing #.

On the other hand, in Comparative Example 2, in which the non-coated surface of the commercially available thermal transfer recording paper was coated with the thermal coating liquid used in Example 1, the black colored state of the thermal transfer recording layer appeared as it was, as show-through, and the thermal coloring layer The printing on the side was very difficult to identify.

Claims (1)

[Scope of Claims] 1. Heat-sensitive thermal transfer recording paper with a heat-sensitive recording layer fully coated on one side of the base material and gallic acid alkyl ester and wax completely coated on the other side, and image receiving paper coated with Fe salt. 1. A thermosensitive thermal transfer recording material comprising a combination of the following, characterized in that the gallic acid alkyl ester has a melting point of 80 to 160°C. 2. The thermosensitive thermal transfer recording material according to claim 1, wherein the gallic acid alkyl ester comprises ethyl gallate, propyl gallate, inamyl gallate, octyl gallate, lauryl gallate, and stearyl gallate. .