JPH0445987A - 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 a second thermal transfer layer by applying a composition containing a thermoplastic resin containing an atomic group having specific bonding moment and a silicone oil wherein a reactive functional group is introduced into the terminal of dimethylpolysiloxane. CONSTITUTION:A first thermal transfer layer being a coloring layer is provided on a base material and a second thermal transfer layer is further provided thereon. In the composition forming the second thermal transfer layer, as a thermoplastic resin containing an atomic group having bonding moment of 1.0 debye or more, a thermoplastic resin containing a hydroxyl group, a carboxyl group an amine group, an amide bond, an ester bond or an urethane bond in its molecule is used. Further pref., silicone oil wherein a reactive functional group represented by a hydroxyl group, an epoxy group or a methacryloxypropyl group is introduced into the single terminal or both terminals of dimethylpolysilocxane is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording medium. 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. At the same time, it prevents the transfer of the thermal transfer layer to the back surface during high temperature and long-term storage.
The present invention relates to a thermal transfer recording medium that prevents printing and running troubles by improving storage stability.

[Conventional technology]

Thermal transfer recording method is widely used because the device is simple, has low noise, is small, low cost, and can easily 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 the speed and resolution of thermal heads have increased in recent years, it has become easier for thermal heads to accumulate heat, and as a result, the temperature of the surrounding area of the heat generating portion also increases, which tends to cause background stains on the transfer paper.

Recently, in order to solve the above problem, one blood of group H (
A heat-resistant protective layer is provided on the back side (hereinafter referred to as the back side), and a heat-resistant protective layer is provided on the other side (hereinafter referred to as the front side) of the base material, and the heat-melting ink layer on the other side (hereinafter referred to as the front side) has a laminated structure. 1
A thermal transfer layer is provided, and on top of that, styrene resin, acrylic resin, polyamide resin, butyral resin, and vinyl chloride/vinyl acetate are used to improve printing properties on low-smooth paper. The structure includes a second thermal transfer layer consisting of a thermoplastic resin such as copolymer resin, ethylene-acid pinot (polymer resin) as the main component, and a mixture of adhesive resin, wax, coloring agent, etc. as necessary. Common.

However, when ribbons with such a structure are stored at high temperatures or for long periods in a rolled state, the top thermal transfer layer migrates to the back side or the heat-resistant protective layer, often causing troubles in printing and running.

According to the structure of conventional thermal transfer recording media, although the printing performance of cover wrap on low-tooth paper, dot reproducibility, and stain resistance can be solved to some extent, it is difficult to print clearly due to high thermal sensitivity. In order to obtain printing, it is necessary to use a thermoplastic resin with a low softening point for the top layer, which is the second thermal transfer layer. However, if a resin with a low softening point is used for the top layer, which is the second thermal transfer layer, will it be possible to store it in a roll at high temperatures or for a long period of time? Then, the resin of the top layer transfers to the back side of the fly that is in direct contact with it or to the heat-resistant protective layer provided on this back side, and the print quality on low-smooth paper is affected due to a decrease in cover wrap properties. Problems such as a decrease in printing quality due to head misalignment of a thermal spatula, a sticking phenomenon, and troubles such as ribbon running in a cassette have occurred.

That is, conventional thermal transfer recording media have poor storage stability such as high temperature and long-term storage, cover-wrapping properties on low-smooth paper, and dot reproducibility. ! ? There was a problem in that printing properties such as IO and scratch resistance were not compatible.

[Problem to be solved by the invention]

1-1 of the present invention is that it prevents the transfer of the thermal transfer layer to the back side of the fly or the heat-resistant protective layer during high temperature and long-term storage, which could not be achieved with conventional products, and prevents transfer to transfer paper with poor smoothness. An object of the present invention is to provide a heat-sensitive transfer recording medium which has greatly improved sharpness and background smearing of transfer paper.

[Child actors to solve problems]

As a result of intensive research to solve the above problem, the present inventors found that the problem could be solved by applying a blended composition containing a specific thermoplastic resin and a specific silicone oil as the second thermal transfer layer. Output 1 - The invention was completed.

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 a fly, and a second thermal transfer layer is further provided on the second thermal transfer layer. A laminated structure coated with a compounded composition containing a combination of one or more thermoplastic resins containing an atomic group having a bonding moment of This is a thermal transfer recording medium.

The reactive functional group introduced at the end of the dimethylpolysiloxane is desirably 2000 g/mol or less based on the functional group equivalent.

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

As the base material, a plastic film with relatively excellent heat resistance such as polyester, polycarbonate I, polyimide, cellophane, paper, etc. with a thickness of 2 to 20 It m can be used, and if necessary, the surface in contact with the thermal head may be A heat-resistant protective layer or a stick-proof layer made of silicone or fluorine-based polymer may also be provided.

The hot melt ink of the first thermal transfer layer comprises a colorant, a vehicle, and various additives. As the colorant, carbon black, organic pigments, dyes, etc. may be used alone or in combination. Preferably, one should be selected that has sufficient color density and does 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, including paraffin wax, carnauba wax,
Microcrystalline wax, candelilla wax, polyethylene wax, wood wax, beeswax, fatty acid amide,
One or more selected from fatty acid esters and the like are used, but the invention is not particularly limited thereto. In addition to the above-mentioned components, various additives such as a fixing agent made of a thermoplastic resin, a dispersing agent, and a leveling agent may be added to the heat-melting ink as necessary.

The composition and thickness of the first thermal transfer layer are determined by the required printing density and thermal sensitivity, but the thickness is 0.1 to 10 μm.
The range is suitable, preferably the range of 2 to 5μ.

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

], thermoplastic resins containing atomic groups having a bonding moment of 0 debye or more (hereinafter simply referred to as thermoplastic resins) include functional groups such as hydroxyl groups, carboxyl groups, and amine groups, and/or amide bonds and ester bonds. , contains atomic groups such as urethane bonds in the molecule, and has a softening point of 50 to 200°C
, preferably one or more thermoplastic resins having a temperature of 70 to 150°C. More preferably, it has good miscibility with silicone oil in which a reactive functional group is introduced at the end of dimethylpolysiloxane, which is another component of the present invention, and furthermore, the mixed composition is applied to the first thermal transfer layer. Alcohols, ketones,
It is best to select one that dissolves in volatile solvents such as esters and hydrocarbons.

The specific silicone oil (hereinafter simply referred to as silicone oil), which is another component of the present invention, has a hydroxyl group, an amine group, an epoxy group, a mercapto group, a carbinol group, or a carbinol group at one or both ends of dimethylpolysiloxane. It is a silicone oil into which a reactive functional group represented by a methacryloxypropyl group, a methacryloxypropyl group, a hydroxyphenethyl group, etc. is introduced, and one type or two or more types thereof are used. In order to obtain a blended composition that meets the requirements of the present invention by mixing with the thermoplastic resin, preferably 2000 g as a functional group equivalent.
It is preferable to use one into which a reactive functional group is introduced so that the amount is less than /mol. Functional group equivalent is 2000 g/mo
In the case of a compounded composition using more than 1 liter of silicone oil, the affinity with the thermoplastic resin may be poor, the coated thin film may be uneven, the silicone oil may bleed, or in extreme cases, the coating liquid may This is not preferable since it causes disadvantages such as phase separation.

Next, a method for preparing a coating composition using the above-mentioned compound will be explained. To mix thermoplastic resin and silicone oil, dissolve and stir using a single or mixed solvent that dissolves both, add the solvent as necessary, and apply high shearing force using a roll mill, pressure kneader, etc. There is a method, for example, of kneading the mixed material using a kneader capable of doing so, and then letting down the mixed wire material with the above-mentioned solvent. The blending ratio of the thermoplastic resin and silicone oil is such that 5 parts by weight to the same amount of silicone oil is added to 100 parts by weight of the thermoplastic resin. If the amount of silicone oil is less than 5 parts by weight, the characteristics of silicone oil will not be expressed, and if it is too much, bleeding or phase separation will occur, which is not preferable. If necessary, a catalyst such as a tin-based compound may be added to both the terminals of the silicone oil in order to promote the reaction between the terminal reactive functional group and the atomic group in the thermoplastic resin having a bonding moment of 1.0 debye or more. It may be added during the mixing or cross-crossing process, or it may be added to a low to medium molecular weight resin such as a 1-stack adhesive agent resin that adjusts the softening point of the thermoplastic resin. It is also possible to add additives such as surface oil agents and leveling agents.The amount of solvent added to the coating composition depends on the type and mixing ratio of the resin and silicone oil used, the amount of solvent, and the coating composition. Although it depends on the processing method and the thickness of the second thermal transfer layer, it is preferably 50 to 99.5% by weight.

In order to obtain the heat-sensitive transfer recording medium of the present invention from the above-mentioned blended composition, a
After constructing the thermal transfer layer using a hot melt method or a solvent method, the blended composition is applied using a known coating method, such as a gravure roll method, a kiss roll method, a tire bar method, etc., and the solvent is volatilized. Then, a second thermal transfer layer is constructed to produce a product. The thickness of the second thermal transfer layer is ('1.05~5.[]μ
m, preferably about 0.1 to 2.0 μm. Furthermore, a release layer or an adhesive layer may be provided between the M5 abutment and the first thermal transfer layer, if necessary.

]0 [Function] 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 reactive functional group at the end of the silicone oil attacks and bonds with the atomic groups in the thermoplastic resin that have a bonding moment of 1.0 Debye or more, and these functional groups and atomic groups Although it varies depending on the type, blending ratio, mixing method, presence or absence of catalyst, etc., it produces covalent bonds, hydrogen bonds, and van der Waals bonds, and part or most of the surface of the second thermal transfer layer is dimethylpolysiloxane with low surface free energy. As a result of being covered with , storage stability such as high temperature and long-term storage is dramatically improved. On the other hand, thermoplastic resins are partially bonded with silicone oil within their molecules, so the inherent properties of thermoplastic resins, such as film-forming properties and thermal responsiveness, remain unchanged. Cover wrap property on paper, reproducibility of Dora I, resistance to 1i! There is no deterioration in printing performance such as I7 resistance.

Bonding moment I of 1.0 debye or more in thermoplastic resin
The proportion of dimethylpolysiloxane in the silicone oil is too large because there is no atomic group with In this case, the thermoplastic resin and silicone oil exist as separate matrices in the second thermal transfer layer, and if they are coated on the first thermal transfer layer, the particles may be badly peeled off, or even if they are not coated uniformly. Even if it were possible to coat it, it would not only be impossible to improve both storage stability and printability, but would also result in a decrease in performance.

〔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% by weight is sufficiently kneaded using a heated triple roll for ink to prepare a hot melt ink, and this is coated on a hot melt gravure roll to form a first thermal transfer layer. did. Next, on this heat-melting ink layer, 50 parts by weight of a polyamide resin having an amide bond in the molecule, 25 parts by weight of Kenne resin as a softening point regulator, and functional group equivalents at both ends of dimethylpolysiloxane are placed. Silicone oil with amine groups introduced at a concentration of 840 g/mol [X-22-161A manufactured by Shin-Etsu Chemical Co., Ltd.]
Pour 25 parts by weight into ethyl acetate and stir thoroughly to prepare an ethyl oxate solution for coating with a concentration of 10 parts, and apply with a wire bar so that the surface layer has a thickness of 1 μm after drying] −
, and dried to construct a second thermal transfer layer to obtain a thermal transfer recording medium of the present invention.

(Example 2) The same procedure as in Example 1 was made until coating the first thermal transfer layer,
Next, on this heat-melting ink layer, 60 parts by weight of an acrylic resin having an ester bond in its molecule and a functional group equivalent at the 11-terminus of dimethylpolysiloxane]3, 1. Silicone oil into which Epoquine groups were introduced so as to give 860 g/mol [X- manufactured by Shin-Etsu Chemical Co., Ltd.]
22173A) 40 parts by weight, catalyst [P manufactured by Shin-Etsu Chemical Co., Ltd.
L4, 0.5 weight, 1 part] and 20 weight parts of I. luene were sufficiently kneaded using a heated two-wood roll, and then poured into ethyl acetate and thoroughly stirred to give a concentration of 10 weight %. [Coating] [Prepare an ethyl acetate-toluene solution, coat with a wire bar so that the surface layer has a thickness of 1 μm after drying, and dry to construct a second thermal transfer layer to prepare a thermal transfer recording medium of the present invention. I got it.

(Comparative Example 1) From the coating composition for the second thermal transfer layer of Example 1, the functional group equivalent weight at both ends of dimethylpolysiloxane was 840 g/
A heat-sensitive transfer recording medium was obtained by applying each coating agent under the same conditions as in Example 1, except for excluding the silicone oil into which amino groups were introduced so as to make the mol ratio.

(Comparative Example 2) The same procedure as in Example 1 was made until coating the thermal transfer layer.
Next, on this heat-melting ink layer, 60 parts by weight of an acrylic resin having an ester bond in the molecule and a silicone oil in which amine groups were introduced at both ends of dimethylpolysiloxane so that the functional group equivalent weight was 3500 g/mat [ After sufficiently kneading 340 parts by weight of X-221,61E manufactured by Shin-Etsu Chemical Co., Ltd., a catalyst (PL4.0.5 parts by weight, manufactured by Shin-Etsu Chemical Co., Ltd.), and 20 parts by weight of toluene using a heated two-wood roll, Pour into ethyl acetate and stir thoroughly until the concentration is 1.
Prepare a 0% by weight ethyl acetate-I-luene solution for coating, and after drying, coat with a wire bar so that the surface layer has a thickness of 1 μm, dry to construct a second thermal transfer layer, and perform thermal transfer. Obtained a recording medium.

(Comparative Example 3) The first thermal transfer layer was prepared in the same manner as in Example 1, except that it was coated with semi-E. Next, on this heat-melting ink layer, 60 parts of an acrylic resin having an ester bond in the molecule, dimethyl 40 parts by weight of silicone oil in which no functional group is introduced at the end of polysiloquiline [KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.],
After thoroughly kneading 20 parts by weight of toluene using two heated rolls, this was poured into ethyl acetate and thoroughly stirred to prepare an ethyl acetate-toluene solution for coating with a concentration of 10% by weight. 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 to obtain a thermal transfer recording medium. However, it was observed that the coating liquid did not wet the first thermal transfer layer, and the first thermal transfer layer was partially exposed.

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 conducted on transfer paper having a Beck smoothness of 50 seconds using a printer. The results are shown in Table 1.

Table [Effects of the Invention] As is clear from the above test results, the thermal transfer recording medium of the present invention has a higher thermal transfer layer base + 4 back surface or heat resistance during high temperature and long-term storage than conventional thermal transfer recording media. Heat-sensitive transfer recording with an excellent laminated structure that prevents migration to the protective layer, and greatly improves the clarity of transfer to receiving paper, which normally has poor smoothness, which is incompatible with this property, and greatly improves background smearing on the receiving paper. It is a medium.

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 is a colored layer. A blended composition containing one or more thermoplastic resins containing an atomic group having a bonding moment of .0 debye or more and a silicone oil in which a reactive functional group is introduced at the end of dimethylpolysiloxane is applied. A thermal transfer recording medium. 2. The thermal transfer recording medium according to claim 1, wherein the reactive functional group introduced at the end of the dimethylpolysiloxane has a functional group equivalent of 2000 g/mol or less.