JPH02160585A - Thermosensitive transfer recording medium - Google Patents

Abstract

PURPOSE:To enable highly frequent use of the subject item by adding a compound expressed by a specific formula to a heat-melting ink composition. CONSTITUTION:Alkylbenzamide substituted with chlorine as expressed by formula I may be used alone as a heat-melting substance in the ink composition of a thermosensitive transfer recording medium or in combination with another heat-melting substance. To ensure achievement of an expected effect, it is recommended that 10 to 70% by weight of alkylbenzamide substituted with chlorine be added to the thermosensitive transfer medium. For instance, a thermosensitive transfer layer is properly formed by applying the thermosensitive transfer composition to the surface of PET, paper, resin film or a metal sheet, and drying the coat to allow the layer to adhere to the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a thermal transfer recording medium, that is, a multi-time ink ribbon for thermal transfer.

[Prior art]

Conventionally, in thermal transfer recording media that can be used many times, it has been well known that a porous resin layer is impregnated with ink, and the ink is leached out in several batches by thermal melting to print. . In this method, the resin layer itself is not transferred even when energy is applied from the thermal head. Therefore, the ratio that contributes to the applied density in the (resin layer ink) layer is ink/(resin+ink).

In order to make it practical, it is necessary to reduce the amount of resin that creates a porous structure, or to make it possible to achieve high printing density with a small amount of ink composition. One way to achieve the latter is to increase the colorant concentration in the ink composition.

However, simply increasing the concentration of the colorant impairs its dispersion with the heat-melting components and increases the melt viscosity of the ink, making it difficult to seep out from the porous structure. As a result, the number of prints decreases and the sensitivity decreases.

〔the purpose〕

An object of the present invention is to provide a thermal transfer recording medium that does not cause the above-mentioned problems even when the coloring material concentration is increased, and can be used many times in practical use.

〔composition〕

As a result of intensive research to achieve the above object, the inventors of the present invention have found that a heat-sensitive transfer recording is made by providing a resin layer having a porous structure on a substrate, and impregnating the pores with a heat-melting ink composition. Provided is a heat-sensitive transfer recording medium, wherein the heat-melting ink composition contains a compound represented by the general formula (I), where R represents an alkyl group having 14 to 20 carbon atoms. It has been found that the above object can be achieved by doing the following.

The chlorine-substituted alkylbenzamide represented by the general formula (I) of the present invention has a wider degree of freedom in selectivity as a material than the conventionally used unsubstituted myristylbenzamide. That is, while conventional unsubstituted myristylbenzamide having an alkyl group other than the myristyl group, which is an alkyl group having 14 carbon atoms, is not practical, the chlorine-substituted alkyl benzamide represented by the general formula N) of the present invention Benzamide having a wide range of alkyl groups having 14 to 20 carbon atoms can be used.

Specific examples of the chlorine-substituted alkylbenzamide represented by the general formula (I) used as the heat-melting component of the ink composition of the thermal transfer recording medium of the present invention are listed below.

C14H,, -NHCO+(4 C1,H37-NHCO+CQ C2°H4, -NHCO+CQ The heat-melting substance used in the present invention is transferred to the receiving paper together with the coloring agent during printing.

The chlorine-substituted alkylbenzamide represented by the general formula (I) of the present invention may be used alone as a heat-melting substance in the ink composition of a thermal transfer recording medium, or may be used in combination with other heat-melting substances. May be used. To achieve the desired effects of the present invention, it is desirable to use the chlorine-substituted alkylbenzamide in the ink composition in an amount of 10 to 70% by weight.

Further, when the chlorine-substituted alkylbenzamide is used in combination with another heat-fusible substance, it is desirable to use the chlorine-substituted alkylbenzamide/other heat-fusible substance in a ratio of 571 to 115.

Examples of heat-melting substances used in combination with chlorine-substituted alkylbenzamide include paraffin wax, microcrystalline wax, ceresin wax, carnauba wax, candelilla wax, montan wax, polyethylene wax, oxidized polyethylene wax, castor wax, and hardened tallow oil. , carbowax, wood wax, lanolin, stearic acid, stearic acid monoglyceride, sorbitan stearate, sorbitol hexastearate, pentaerythritol stearate, polyoxyethylene monostearate, stearyl alcohol, other synthetic oxidized waxes, synthetic and natural esters There are waxes, hydrogenated waxes, etc.

Also, petrolatum, a paste or liquid mineral oil, which has the effect of adjusting the melting point of the solid ink and the dispersion effect of stably forming a solid ink continuous phase in the microporous resin layer, either alone or in combination.

Oleic acid, castor oil, cottonseed oil, tallow oil, octyl alcohol, glycerin, triethylene glycol, polyalkylene glycol and its derivatives, polyoxyalkylene glycol and its derivatives, sorbitan fatty acid ester, sorbitol fatty acid ester, glycerin fatty acid ester, erythritol fatty acid ester , pentaerythritol fatty acid ester, polyoxyethylene alkylamine, etc. are also used as part of the solid component. These components may be used alone or in combination. Further, these components are selected depending on the combination with the microporous resin, and the important point in selecting these components is that they should be kept immiscible with the selected resin. Further, the melting point of the solid component is determined by the characteristics and recording speed of the thermal recording printer head to which the thermal transfer medium is applied, and the composition is determined.

In addition, the colorant components used in the present invention include commonly used dyes, pigments, and other substances capable of coloring and recording.
For example, basic base dyes.

Neozabopon dye, Zapon dye, azo oil-soluble dye (S
OT), carbon black, lake red, alkali blue, navy blue crystal violet lactone, magnetic iron oxide, etc.

In order to obtain high print density even with a small amount of the ink composition, the colorant concentration in the ink composition is preferably 30% by weight or more, for example, about 35 to 45% by weight.

As the resin having a porous structure, conventionally known polyvinyl alcohol, vinyl chloride-vinyl acetate copolymer, butyral resin, cellulose acetate, cellulose acetate butyrate resin, etc. can be used.

In order to maintain the porous structure even when energy is applied, it is desirable that the glass transition point of the resin is 90°C or higher, more preferably 100°C or higher.

The weight ratio of ink composition:resin is preferably 6:1 to 2:1. Outside this range, the multi-time printing characteristics will be significantly degraded.

Examples of solvent components include organic solvents such as toluene, ethyl acetate MEK, and methanol, and water.

These solvents are selected in combination to form a dispersion medium in the solvent range for the selected resin and the solvent range for the solid component, and in the case of a single range, they are used as a mixture.

The heat-sensitive transfer medium of the present invention is prepared by coating a heat-sensitive transfer composition having the above structure on a support such as a sheet of PET, paper, resin film, metal, etc. by a conventional method and drying the composition to form a heat-sensitive transfer layer as appropriate. , can be made by bringing them into close contact.

In order to help the adhesion between the support and the heat-sensitive transfer layer, commonly known resins such as polyester, vinyl chloride, vinyl acetate copolymers, acrylic resins, vinyl chloride resins, and plasticizers are added to the support in advance. An undercoat adhesive layer may be provided.

The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Cellulose acetate butyrate 10 toluene
20 MEK 20 [Ink liquid] Neozapon black X-5412 Carnauba wax 9 Toluene
50 M E K 100 The above solution was coated on a PET film with a CAB adhesive layer of 0.5 μm using a wire bar to obtain an ink layer of 7 μm.

I used this as an ink ribbon and used Ricoh's Warb oJP50.
As a result of a printing experiment with E, printing with O, D = 1.0 or more was repeatedly possible 5 times. Further, even when the ink ribbon was left in a high temperature environment of 50° C. for 7 hours, no deterioration in print density (0, D,) was observed.

Example 2 In Example 1, parachlormyristylbenzamide (C1
, H2,N HCO-@-CQ melting point = 68°C] was prepared in exactly the same manner as in Example 1, and a printing test was conducted. There was no background smudge.
Good print density was obtained even after multiple printings, and there was no deterioration of printing characteristics over time.

Example 3 In Example 1, parachlorostearylbenzamide [Cney Hs?] was used instead of orthochlorostearylbenzamide. A thermal transfer recording medium was prepared in exactly the same manner as in Example 1 except that NHCO-◎-CQ melting point = 80°C] was used, and a printing test was conducted. However, good print density was obtained even when printing was performed, and there was no deterioration of print characteristics over time.

Example 4 In Example 1, parachloroeicosylbenzamide (C2
A thermal transfer recording medium was prepared in exactly the same manner as in Example 1, except that a H4□NHCO-◎-cp melting point = 90°C] was used, and a printing test was conducted. There was no background smudge.
Good print density was obtained even after multiple printings, and there was no deterioration of printing characteristics over time.

Example 5 Polyvinyl alcohol 5 water
150 [Ink liquid] SOT Black-6 (manufactured by Hodogaya Chemical) 6
Orthochlorstearylbenzamide 10SPA
N-60 (surfactant) 4 Toluene 30 The above liquid was coated on a PET film with a vinyl acetate adhesive layer of 0.5 μm using a wire bar to obtain an ink layer of 7 μm.

A printing experiment was conducted on this in the same manner as in Example 1, and the same results were obtained.

In addition, an experiment was conducted to check the heat-resistant storage stability (50° C., 7 hours) of the ink ribbon, but no deterioration was observed (◯, D).

Comparative Example In Example 1, parachlorlaurylbenzamide [Cl2
A thermal transfer recording medium was prepared in exactly the same manner as in Example 1, except that H2,N HCO-■-cn melting point = 58°C] was used, and when a printing test was performed, background smear occurred and it was not used for practical use. I couldn't do that.

〔effect〕

As described above, the heat-sensitive transfer recording medium using the chlorine-substituted alkylbenzamide represented by the general formula (I) of the present invention as a heat-melting component in the ink composition has good colorant dispersibility.

The concentration of colorant contained in the ink composition can be increased, even if the amount of ink composition transferred is small.

A sufficiently high printing density (0, D) can be obtained, and a product with excellent multi-printing characteristics can be obtained.

In addition, the chlorine-substituted alkylbenzamide of the present invention can be used in a wide range of alkyl groups having 14 to 20 carbon atoms,
There is a very wide degree of freedom in material selection.

Claims (1)

[Scope of Claims] 1. A thermal transfer recording medium in which a resin layer having a porous structure is provided on a substrate, and the pores of the resin layer are impregnated with a thermofusible ink composition, wherein the thermofusible ink composition Things have general formulas (I), ▲mathematical formulas, chemical formulas, tables, etc.▼(I
) (R represents an alkyl group having 14 to 20 carbon atoms).