JPH0445988A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent the transfer of a thermal transfer layer to the rear of a base material or a heat-resistant protective layer during high temp. long-term preservation by forming the second thermal transfer layer provided on the first thermal transfer layer on the base material by applying a composition containing a thermoplastic resin having a component selected from a hydroxyl group, a carboxyl group and an amide bond and silicone oil wherein an amine group becoming specific amine valency is introduced into the methyl group excepting the terminal of dimethylpolysiloxane. CONSTITUTION:The first thermal transfer layer being a coloring layer is provided on a base material and the second thermal transfer layer is further provided thereon. The second thermal transfer layer is formed by applying a composition wherein a thermoplastic resin having at least one kind of a group or bonding group selected from a group consisting of a hydroxyl group, a carboxyl group and an amide bond is combined with amine modified silicone oil wherein an amine group is introduced into the methyl group bonded to the Si atom excepting of the terminal of dimethylpolysiloxane so as to become 2000g/mol or less as amine equivalency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to thermal transfer recording media. Specifically, compared to heat-sensitive transfer recording media that have a heat-melting ink layer with a conventional laminated structure, it maintains cover wrap properties on transfer paper, which is inferior in smoothness, and high heat sensitivity such as dot reproducibility. However, it prevents the transfer of the thermal transfer layer to the back surface during high temperature and long-term storage.
11. Prevents printing and running troubles by improving storage stability.

The present invention relates to a thermal transfer recording medium.

[Conventional technology]

Thermal transfer recording method is widely used because the device is simple, has low noise, is small, low cost, and can record on plain paper. However, the print quality is easily affected by the surface smoothness of the transfer paper, and it has been difficult to make clear prints on the transfer paper with poor surface smoothness.

In addition, as thermal heads have become faster and have higher resolution in recent years, it has become easier for thermal heads to accumulate heat, and as a result, the temperature around the heat generating part also increases, causing other stains on the transfer paper. It's easy to do.

Recently, in order to solve the above problem, one side of the group H (
A heat-resistant protective layer with stick protection 1-1 is provided on the other side (hereinafter referred to as the front side) of the base H (hereinafter referred to as the front side).
The heat-melting ink layer has a laminated structure, and the first colored layer
A thermal transfer layer is provided, and on top of that, styrene resin, acrylic resin, polyamide resin, butyral resin, and vinyl chloride/vinyl acetate copolymer resin are used to improve printability on low-smooth paper, improve adhesion, and stain resistance. , a second resin mainly composed of a thermoplastic resin such as ethylene-vinyl acetate copolymer resin, and a mixture of tackifier resin, wax, colorant, etc. as necessary.
A structure in which a thermal transfer layer is provided is common.

However, when ribbons with such a structure are stored at high temperatures or for long periods in a rolled state, the thermal transfer layer of the I/tube migrates to the heat-resistant protective layer on the back surface, which often causes problems in printing and running.

According to the structure of conventional thermal transfer recording media, printing performance such as cover wrap property on low-smooth paper, dot reproducibility, and background stain resistance can be solved to some extent, but bright printing due to high thermal sensitivity is not possible. In order to obtain the second thermal transfer layer, I.
It has become necessary to use a thermoplastic resin with a low softening point as the thermoplastic resin for the bulge layer. However, when a resin with a low softening point is used for the top layer, which is the second thermal transfer layer, if it is stored in a roll at a high temperature or for a long time, the resin of the top layer may be formed on the back surface of the sample that is in direct contact with it or on this back surface. The ribbon migrates to the heat-resistant protective layer that is attached to the cassette, resulting in poor cover wrap properties and poor print quality on low-smooth paper, poor print quality due to thermal head dirt, sticking phenomenon, and ribbon running inside the cassette. There were 41 problems including the occurrence of the above troubles.

In other words, with conventional thermal transfer recording media, there was a problem that it was not possible to achieve both high-temperature and long-term storage stability, and printability such as cover-wrap performance on low-smooth paper, dot reproducibility, and stain resistance. .

[Invention or problem to be solved]

The purpose of the present invention is to prevent the transfer of the thermal transfer layer to the back side of the sample or the heat-resistant protective layer during high-temperature and long-term storage, which was not possible with conventional products, and to improve the clarity of transfer to transfer paper with poor smoothness. It is an object of the present invention to provide a thermal transfer recording medium in which background smear on transfer paper is significantly improved.

[Means to solve the problem]

As a result of intensive research to solve the above problem, the present inventors have found that the problem can be solved by applying a blended composition containing a specific thermoplastic resin and a specific silicone oil as the second thermal transfer layer. Miyama completed the present invention.

That is, the present invention provides a thermal transfer recording medium having a laminated structure in which a first thermal transfer layer, which is a colored layer, is provided on base +4, and a second thermal transfer layer is further provided thereon. and an amide bond, and a thermoplastic resin having at least one group or bonding group selected from the group consisting of amide bonds, and 2000 g as an amine equivalent to the methyl group bonded to the Si atom excluding the terminal of dimethylpolysiloxane.
This is a heat-sensitive transfer recording medium coated with a blended composition of amine-modified silicone oil into which amine groups have been introduced so as to have a concentration of /mo1 or less.

Next, the configuration of the present invention will be explained.

As a sample, a comparatively curved surface made of polyester, polycarbonate, polyimide, etc. with an IV diameter of 2 to 20 lt m, a plastic film with excellent heat resistance, cellophane, paper, etc. can be used, and if necessary, silicone can be used on the surface in contact with the thermal head. A heat-resistant protective layer or a stick rainproof layer made of a fluorine-based or fluorine-based polymer may be provided.

The hot melt ink of the first thermal transfer layer consists of a colorant, a vehicle, and various additives. As the coloring agent, carbon black, organic pigments, dyes, etc. can be used alone or in combination. Preferably has sufficient coloring density,
It is best to choose one that will not discolor or fade due to light, heat, temperature/humidity, solvents, etc.

The main component of the vehicle is wax with a melting point of 45 to 120°C, and one selected from paraffin wax, carnauba wax, microcrystalline wax, candelilla wax, polyethylene wax, wood wax, beeswax, fatty acid amide, fatty acid ester, etc. Although two or more types are used, there is no particular limitation in the present invention. In addition to the above-mentioned components, the heat-melting ink may contain various additives such as a fixing agent, a dispersing agent, and a leveling agent made of a thermoplastic resin, if necessary.

The composition and thickness of the first thermal transfer layer are determined by the required printing density and thermal sensitivity;
A range of μ is suitable, preferably a range of 2 to 5 μ.

Next, the composition for forming the second thermal transfer layer will be explained.

Thermoplastic resins containing at least one group or bonding group selected from the group consisting of hydroxyl groups, carboxyl groups, and amide bonds (hereinafter simply referred to as thermoplastic resins) include cellulose derivatives, polyvinyl alcohol derivatives, polyamide resins, etc. Softening point of 50-200℃, preferably 70-200℃
One or more thermoplastic resins having a temperature of 150°C are used.

More preferably, the miscibility with an amine-modified silicone oil in which an amine group is introduced into the methyl group of dimethylpolysiloxane, which is another component of the present invention, and the mixed composition is applied to the first thermal transfer layer in the form of a thin film. For easy application, it is recommended to select a material that has good solubility in volatile solvents such as alcohols, ketones, esters, and hydrocarbons.

A specific silicone oil (hereinafter simply referred to as amine-modified silicone oil), which is another component of the present invention, contains an aliphatic amine compound, etc. This is an amine-modified silicone oil in which amine groups are introduced by reacting with the silicone oil, and one or more of them are used. In order to obtain a blended composition that complies with [1] of the present invention by mixing with the thermoplastic resin, it is necessary to use a composition into which amine groups have been introduced so that the amine equivalent is 2000 g/mol or less.

In the case of a compounded composition using an amine-modified silicone oil with an amine equivalent of more than 2000 g/mol, the affinity with the thermoplastic resin is poor, and the applied thin film may be uneven, the amine-modified silicone oil may bleed, or In such cases, disadvantages such as phase separation in the liquid state may occur, which is not preferable.

Next, a method for preparing a coating composition using the above-mentioned compound will be explained. To mix the thermoplastic resin and amine-modified silicone oil, dissolve and stir using a single or mixed solvent that dissolves both, add the above solvent as necessary, and use a high shear method such as a roll mill or pressure kneader. There is a method in which the kneaded product is kneaded using a kneader capable of applying force, and then the kneaded product is let down with the above-mentioned solvent. The blending ratio of the thermoplastic resin and the amine-modified silicone oil is such that 5 parts by weight to an equivalent amount of the amine-modified silicone oil is added to 1 c'l 0 parts by weight of the thermoplastic resin. If the amount of the amine-modified silicone oil is less than 5 parts by weight, the characteristics of the amine-modified silicone oil will not be expressed, and if it is too large, bleeding or phase separation will occur, which is not preferable. If necessary, a LI-like, tin-based compound, etc. that promotes the reaction between the amine group of the amine-modified silicone oil and the hydrogen atom at the end of the hydroxyl group and/or carboxyl group and/or amide bond in the thermoplastic resin may be added. A catalyst may be added during the mixing or cross-crossing process of the two, or a low to medium molecular resin such as a tackifier resin may be added for the purpose of adjusting the softening point of the thermoplastic resin. Furthermore, it is possible to add additives such as interfacial sealants, q-adjusting agents, and leveling agents. The amount of solvent added to the coating composition depends on the type and mixing ratio of the resin and amine-modified silicone oil used, the amount of solvent, the second coating method, and the thickness of the second thermal transfer layer.
The amount of rfI is preferably 0 to 99.5%.

The heat-sensitive transfer recording medium of the present invention is prepared from the above-mentioned blended composition.
1j, after constructing a first thermal transfer layer on base H on which a heat-resistant and insulating Xi layer is provided as necessary, using a hot melt I method or a solvent method, the above-mentioned blended composition is applied by a known coating method, i.e. Coating is performed using a gravure roll method, a kiss roll method, a tire bar method, etc., and the solvent is evaporated to construct a second thermal transfer layer to produce a product. The thickness of the second thermal transfer layer is 0.05 to 5.0 μm
It is preferably in the range of 0.1 to 2, θμm. Further, if necessary, a release layer or a contact layer 1'J may be provided between the base +4 and the first thermal transfer layer.

[Effect]

The function of the heat-sensitive transfer recording medium having a heat-melting ink layer having a laminated structure according to the present invention is estimated as follows.

In the second thermal transfer layer, the amine groups in the amine-modified silicone oil attack and bond to the terminal hydrogen atoms of the hydroxyl groups and/or carboxyl groups and/or amide bonds in the thermoplastic resin, resulting in the formation of these functional groups and atomic groups. Although it varies depending on the type, blending ratio, mixing method, presence or absence of catalyst, etc., hydrogen bonds and van der Waals bonds are made to be 41", and a part or most of the surface of the second thermal transfer layer has a low energy. As a result of being covered with dimethylpolysiloxane, the storage stability at high temperatures and long-term storage is dramatically improved.The thermoplastic resin is partially bonded to the amine-modified silicone oil within the molecule, so the thermoplastic resin The original properties of the resin, such as film-forming properties and thermal responsiveness, remain unchanged, so it is possible to improve printing properties such as cover wrap properties on low-smooth paper, dot reproducibility, and dirt resistance. There's no low C.

If there is no hydroxyl group and/or carboxyl group and/or amide bond in the thermoplastic resin, if the dimethylpolysiloxane has no amine group introduced, or if the amine equivalent is above a certain level, the dimethylpolysiloxane in the amine-modified silicone oil If the area is too large, the thermoplastic resin and amine-modified silicone oil may exist as separate matrices in the second thermal transfer layer, causing wetness when coated on the first thermal transfer layer. Even if it were possible to apply it uniformly, it not only fails to improve both storage stability and printability, but also causes poor performance.]7 This will result in a crash.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

(Example 1) 15% by weight of ethylene-vinyl acetate copolymer resin and 20% by weight of carbon black were added to a 4.0 μm thick polyester film with a heat-resistant protective layer made of silicone resin on the back side.
, carnauba wax 20% by weight, paraffin wax 4
A blended composition consisting of 5 ffl [%] was heated and sufficiently kneaded using a Miki roll for ink to prepare a hot melt ink, which was coated with a hot melt gravure roll to form the first thermal transfer layer. . Next, on this heat-melting ink layer, 50 parts by weight of polyvinyl butyral having a hydroxyl group in the molecule, a softening point regulator and 25 parts by weight of Kenne resin.
parts by weight, excluding the terminal end of dimethylpolysiloxane (the methyl group bonded to the Si atom has an amine equivalent of 830 g/ma)
Add 25 parts by weight of amine-modified silicone oil (KF857, manufactured by Shin-Etsu Chemical Oki) into ethyl acetate and stir thoroughly at 1, concentration of 10.
% by weight of ethyl acetate solution for coating was prepared, and after drying, the surface layer was coated with a wire bar to a thickness of 1 μm, and dried to construct a second thermal transfer layer, thereby producing a thermal transfer recording medium of the present invention. I got it.

(Example 2) The process was made in the same manner as in Example 1 until the first thermal transfer layer was applied. Next, 60 weight of alcohol-soluble polyamide resin having an amide bond in the molecule was placed on top of this heat-melting ink layer. part, the terminal of dimethylpolysiloxane was removed (the methyl group bonded to the Si atom had an amine equivalent of 360 g/not)
40 parts by weight of amine-modified silicone oil [KF39B, manufactured by Shin-Etsu Chemical Co., Ltd.], 0.5 parts by weight of PL4, manufactured by Shin-Etsu Chemical Co., Ltd.], 10 parts by weight of isopropyl alcohol, After thoroughly kneading 10 parts of ethyl acetate using a heated two-piece roll,
Pour this into ethyl acetate and stir thoroughly with j- to a concentration of 1.
Prepare a 0% by weight 1% ethyl acetate-isopropyl alcohol solution for coating in Steps 1 to 1. After drying, coat with a wire bar so that the surface layer becomes 1 μm thick, and dry to construct a second thermal transfer layer. , a thermal transfer recording medium of the present invention was obtained.

(Comparative Example 1) Each coating agent was applied to a thermal transfer recording medium under the same conditions as in Example 1, except that the amine-modified silicone oil was removed from the coating composition for the second thermal transfer layer. I got it.

(Comparative Example 2) Made in the same manner as Example 1 until coating the first thermal transfer layer,
Next, in this heat-melting ink layer, 60 parts by weight of an alcohol-soluble polyamide having an amide bond in the molecule, and an amine equivalent of 4400 g/mol in the methyl group bonded to the St atom excluding the terminal of dimethylpolysiloxane were added. Amine-modified silicone oil with amine groups introduced so that
Using a heated wooden roll, 40 parts by weight of KF865 (manufactured by Shin-Etsu Chemical Co., Ltd.), a catalyst (PL4.0.5 parts by weight, manufactured by Shin-Etsu Chemical Co., Ltd.), 10 parts by weight of isopropyl alcohol, and 10 parts by weight of ethyl acetate were heated. After sufficiently kneading, this was poured into ethyl acetate and thoroughly stirred to prepare an ethyl acetate-isopropyl alcohol solution for coating T with a concentration of 10% by weight, so that the surface layer would have a thickness of 1 μm after drying. A second thermal transfer layer is constructed by coating and drying with a wire bar to obtain a thermal transfer recording medium.

Next, the thermal transfer recording medium obtained by the above operation was wound up into a roll and stored at 60°C for 24 hours, and the degree of transfer of the second thermal transfer layer to the heat-resistant protective layer was observed using a microscope. A printing test was carried out using a type printer on transfer paper with a Beck smoothness of 50 seconds. The results are shown in Table 1.

Table 1 [Effects of the Invention] As is clear from the test results in item 1, the thermal transfer recording medium of the present invention has a lower thermal transfer layer base during high-temperature and long-term storage than conventional thermal transfer recording media. Excellent lamination that prevents migration to the back side of the material or the heat-resistant protective layer, and greatly improves the clarity of transfer to the transfer paper, which has poor smoothness, which is difficult to reconcile with this property, and the background smearing of the transfer paper. It is a thermal transfer recording medium with a structure of

Claims (1)

[Claims] 1. In a thermal transfer recording medium having a laminated structure in which a first thermal transfer layer, which is a colored layer, is provided on a base material, and a second thermal transfer layer is further provided thereon, the second thermal transfer layer has hydroxyl groups, carboxyl groups, and amide bonds. at least one selected from the group consisting of
A thermoplastic resin having a seed group or a bonding group, and an amine-modified silicone oil in which amine groups are introduced into the methyl groups bonded to Si atoms excluding the ends of dimethylpolysiloxane so that the amine equivalent is 2000 g/mol or less. A heat-sensitive transfer recording medium coated with a blended composition containing.