JPH0633030A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive composition capable of giving high adhesive force without the need for any curing agent, excellent in stability with time, esp. suitable for bonding of an ink layer to a substrate for heat-sensitive transfer recording media, containing a polyamide and an organoboron compound polymer. CONSTITUTION:A mixture of (A) a polyamide (e.g. nylon 66) and (B) an organoboron compound polymer, pref. a polyester bearing acidic chelate complex residue from a polyol and boric acid, esp. pref. a di(glycerol)borate dicarboxylate derivative polymer of the formula (R is residue except for the COOH group of dicarboxylic acids, e.g. tetramethylene, 1,2-phenylene, or 1,4-phenylene residue), is incorporated, as necessary, with ingredient(s) such as a pigment followed by kneading together with a solvent using e.g. a ball mill, thus obtaining the objective adhesive composition. The adhesive composition prepared by incorporating 100 pts.wt. of the component A with <=100 pts.wt. of the component B is used as an adhesive layer for heat-sensitive transfer recording media each made up of a substrate, adhesive layer and ink layer laminated in this order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition which has a high adhesive force without using a curing agent and is stable over time. More specifically, it relates to an adhesive composition suitable for adhering a support of a thermal transfer recording medium such as an ink ribbon used in a thermal transfer system to an ink layer. The present invention also relates to a heat-sensitive transfer recording medium having a constitution in which a support and an ink layer are bonded with the adhesive composition.

[0002]

2. Description of the Related Art In recent years, with the widespread use of personal computers and word processors and the development of video printers, the thermal transfer recording method has come to be widely used as a method for hard copying character information and image information. ing.

As one of the heat-sensitive transfer recording media used in such a heat-sensitive transfer recording system, an ink layer composed of a dye such as a heat sublimation dye or a heat-melt transfer dye and a binder resin holding the dye is polyester. It is laminated on one side of a support such as a film, and on the other side of the support, the thermal transfer recording medium is prevented from sticking to the thermal head due to the heat of the thermal head. A laminate having a heat resistant slipping layer laminated thereon is used so that the heat resistant slippery layer can be transported to.

When recording is performed using such a heat-sensitive transfer recording medium, the ink layer of the heat-sensitive transfer recording medium is superposed on the dye receiving layer side of the printing paper provided with the dye receiving layer, and the heat-sensitive transfer recording medium is formed. Heat is applied from the heat resistant slipping layer side according to the image information by a thermal head to transfer the dye in the ink layer to the dye receiving layer of the printing paper. Therefore, the support and the ink layer are bonded with an adhesive so that the ink layer itself does not peel off from the support of the thermal recording medium.

As an adhesive used for such a purpose, a polyester film is generally used as a support, and therefore, it is crosslinked with a diisocyanate-containing curing agent having good adhesion to polyester. Polyurethane adhesives are used.

[0006]

However, in a heat-sensitive transfer recording medium in which a support and an ink layer are adhered with a polyurethane adhesive, it is difficult to say that the adhesive strength of the polyurethane adhesive is sufficient. There is a problem that the ink layer may peel off from the support during thermal transfer and stick to photographic paper, so-called fusion.

Further, since the conventional polyurethane adhesive is a curable type, that is, an adhesive which has a high molecular weight at the time of coating, the pot life is as short as about 12 hours, and therefore it is troublesome to handle. However, there is also a problem that the plate used when applying the polyurethane adhesive is likely to be clogged.

The present invention is intended to solve the problems of the prior art, and has a high adhesive force without using a curing agent in place of the polyurethane adhesive,
Moreover, it is an object of the present invention to provide an adhesive composition which is stable over time and is particularly suitable for bonding a support of a thermal transfer recording medium such as an ink ribbon used in a thermal transfer system to an ink layer. Another object of the present invention is to provide a heat-sensitive transfer recording medium in which a support and an ink layer are adhered with such an adhesive composition and there is no problem of so-called fusion during printing.

[0009]

The inventors of the present invention have been
Although it has excellent heat resistance, the use of a polyamide, which has not been used as an adhesive due to a problem in adhesive strength, and an organic boron compound polymer in combination yields excellent adhesive strength. It was found that the present invention has been completed.

That is, the present invention provides an adhesive composition containing a polyamide and an organic boron compound polymer.

The present invention also provides a thermal transfer recording medium in which a support, an adhesive layer, and an ink layer are sequentially laminated,
Provided is a thermal transfer recording medium in which the adhesive layer is composed of a mixture of polyamide and an organic boron compound polymer.

The present invention will be described in detail below.

The adhesive composition of the present invention contains a polyamide and an organic boron compound polymer. Thus, by using the polyamide and the organic boron compound polymer in combination, it becomes possible to maintain a sufficient adhesive force even from room temperature to high temperature (about 200 ° C. or higher). Also, unlike conventional polyurethane adhesives, no curing agent is used, so that the pot life is at least 10 times that of polyurethane adhesives without increasing the molecular weight during coating. Moreover, plate clogging does not occur during coating.

The organic boron compound polymer used in the present invention has the formula (2)

[0015]

[Chemical 2] A polyester containing an acidic chelate complex residue of a polyol and boric acid represented by can be used. Among them, a liquid polyester is more preferable because it allows uniform and easy mixing with a polyamide. Specific examples of the polyester containing such an acidic chelate complex residue of a polyol and boric acid include compounds represented by the formula (1)

[0016]

[Chemical 3] The di (glycerin) borate dicarboxylate derivative polymer represented by is preferably exemplified. In addition, R in the formula (1) represents a residue other than the carboxyl group of the dicarboxylic acid, and varies depending on the dicarboxylic acid used. As the dicarboxylic acid component in the formula (1), when a general polyester dicarboxylic acid component such as adipic acid, phthalic acid or terephthalic acid is used, R is a tetramethylene residue or 1,2- It becomes a phenylene residue and a 1,4-phenylene residue.

The polyamide used in the present invention can be appropriately selected from polyamides conventionally used for synthetic fibers and the like according to the use conditions of the adhesive composition and the like. For example, nylon 6, nylon 6,6 and other aliphatic polyamides, ethylenediamine,
Diamines such as diethylenetriamine and polyamides derived from triamines and dimer acid can be preferably used.

As the polyamide, an adhesive composition is produced by using a polyamide that is soluble in a solvent that dissolves the above-mentioned organic boron compound polymer, for example, an alcohol such as methanol or ethanol, or a solvent such as DMF or THF. It is preferable because it can be easily handled in the case of coating.

In the adhesive composition of the present invention,
The mixing ratio of the polyamide and the organic boron compound polymer is
The ratio can be appropriately changed depending on the purpose of use. For example, when the adhesive composition of the present invention is applied to the adhesion between the support of a thermal transfer recording medium such as an ink ribbon and the ink layer, the adhesive layer formed from the adhesive composition does not become sticky at room temperature. For this reason, it is preferable that the amount of the organic boron compound polymer is 100 parts by weight or less with respect to 100 parts by weight of polyamide.

In addition to the polyamide and the organic boron compound polymer, various additives such as pigments can be added to the adhesive composition of the present invention.

The adhesive composition of the present invention can be produced by mixing the polyamide and the organic boron compound together with a solvent by a ball mill or the like and stirring.

The adhesive composition of the present invention described above is
It can be used in a variety of applications, but preferably in FIG.
It can be preferably applied to form the adhesive layer 2 of the thermal transfer recording medium in which the support 1, the adhesive layer 2 and the ink layer 3 are sequentially laminated as shown. This thermal transfer recording medium is also a part of this invention.

As described above, when the adhesive layer 2 of the thermal transfer recording medium is formed from the adhesive composition of the present invention, it is used as the support 1 from room temperature during storage to a high temperature (200 ° C. or higher) during printing. The ink layer 3 can be firmly adhered, and the fusing phenomenon in which the ink layer 3 itself transfers to the printing paper at the time of printing can be suppressed. Further, since the adhesive layer 2 is substantially insoluble in a hydrocarbon solvent such as toluene or paraffin, it is attacked by the solvent in the ink composition for forming the ink layer 3 on the adhesive layer 2. Never. Therefore, even if the ink layer 3 is formed on the adhesive layer 2, the adhesive force of the adhesive layer 2 hardly changes. Furthermore, since plate clogging does not occur when the adhesive layer is formed, it is possible to form the adhesive layer with good mass productivity.

The heat-sensitive transfer recording medium of the present invention may have the same structure as that of the conventional heat-sensitive transfer recording medium except that the adhesive layer is formed of the adhesive composition of the present invention. Therefore, the heat resistant slipping layer 4 may be formed on the back surface of the support 1.

The thermal transfer recording medium of the present invention can be manufactured by a conventional method. For example, the adhesive composition of the present invention is applied to the surface of the support provided with the heat resistant slipping layer on which the heat resistant slipping layer is not formed and dried to form an adhesive layer, and a dye is formed thereon. The ink composition can be manufactured by uniformly coating a binder resin, a solvent and the like, and coating and drying the ink composition according to a conventional method to form an ink layer.

[0026]

Since the adhesive composition of the present invention uses the polyamide and the organoboron compound polymer in combination, it is possible to realize high adhesive strength without using a curing agent, and also to improve stability with time. It is possible to earn. Further, the heat-sensitive transfer recording medium having an adhesive layer formed from this adhesive composition can suppress a so-called fusion phenomenon in which the ink layer is transferred to the printing paper at the time of printing.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 An adhesive composition was produced by uniformly mixing the components of the following composition with a ball mill.

Adhesive composition Nylon (Nippon Rilsan; trade name 1276TE) 5 parts by weight Organoboron compound polymer 1 part by weight (Boron International; trade name Hyboron DLG-1100K) Ethanol 50 parts by weight Toluene 50 parts by weight The composition was left to stand at 30 ° C. for 10 days, but remained unchanged and could be stably stored.

Example 2 An adhesive composition was produced by uniformly mixing the components of the following composition with a ball mill.

Adhesive composition Nylon (Teikoku Kagaku; trade name Tredin MF-30) 5 parts by weight Organoboron compound polymer 3 parts by weight (Boron International; trade name Hyboron DLG-1100K) Ethanol 90 parts by weight MEK 10 parts by weight The adhesive composition was left at 30 ° C. for 10 days, but it could be stably stored without any change.

Comparative Example 1 An adhesive composition was produced by uniformly mixing the components of the following composition with a ball mill.

Adhesive composition Polyester urethane 10 parts by weight (Nippon Polyurethane Industry Co., Ltd .; trade name DN3870) Trifunctional polyisocyanate type crosslinking agent 0.5 parts by weight (Nippon Polyurethane Industry Co., Ltd. trade name: Coronate L) MEK 50 parts by weight Toluene 50 parts by weight The resulting adhesive composition started to increase in solution viscosity within a few hours after mixing, and completely gelled after one day, making it impossible to apply.

Example 3 The adhesive composition of Example 1 was applied to the surface of a polyethylene terephthalate film having a heat resistant slipping layer formed on the back surface thereof using a gravure coater at a coating speed of 20 m / min to obtain a wet thickness. It was applied to a thickness of about 2 μm and dried in a hot air drying oven at 110 ° C. to form an adhesive layer.

On this adhesive layer, an ink composition having the following composition was applied and dried to form an ink layer, whereby an ink ribbon (length 2 × 10 ⁴ m) was produced. At this time, the gravure plate cylinder was not clogged, and no more than visually observed on the ink ribbon forming surface.

Ink composition Ethyl hydroxycellulose (Low) 10 parts by weight (manufactured by Hercules) 3 parts by weight of the dye of formula (3)

[0037]

[Chemical 4] MEK 50 parts by weight Toluene 50 parts by weight The ink ribbon thus obtained is mounted on a color video printer (manufactured by Sony Corporation), and step printed on a video printing paper (manufactured by Sony Corporation; VPM-30STA). As a result, a clear image was obtained without the ink layer being fused to the printing paper.

Also, an ink ribbon having the same performance could be produced by using the adhesive composition of Example 1 after storage at 30 ° C. for 10 days.

Example 4 An ink ribbon was produced by repeating Example 3 except that the adhesive composition of Example 2 was used. At this time,
No clogging occurred on the gravure plate cylinder, and no more than visually observed on the ink ribbon forming surface. When this ink ribbon was subjected to step printing in the same manner as in Example 3, a clear image was obtained as in Example 3, without the ink layer being fused to the printing paper. Also, an ink ribbon having the same performance could be produced by using the adhesive composition of Example 2 after storage at 30 ° C. for 10 days.

Comparative Example 2 An ink ribbon was produced in the same manner as in Example 3 except that the adhesive composition of Comparative Example 1 was used. In this case, when the ink ribbon was manufactured at 2 × 3 × 10 ³ m, chipping or unevenness began to occur on the ink application surface, and a mottled pattern was observed at the time of manufacturing 1 × 10 ⁴ m. Further, the surface of the gravure plate cylinder was clogged with fine resin powder.

[0041]

EFFECT OF THE INVENTION According to the adhesive composition of the present invention, high adhesive strength can be realized without using a curing agent, and stability with time can be obtained. Further, according to the heat-sensitive transfer recording medium having an adhesive layer formed from the adhesive composition of the present invention, it is possible to suppress the phenomenon of so-called fusing that the ink layer is transferred to the printing paper during printing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one embodiment of a thermal transfer recording medium of the present invention.

[Explanation of symbols]

 1 Support 2 Adhesive Layer 3 Ink Layer 4 Heat Resistant Sliding Layer

Claims (8)

[Claims] 1. An adhesive composition comprising a polyamide and an organic boron compound polymer. 2. The adhesive composition according to claim 1, wherein the organic boron compound polymer is a polyester containing an acidic chelate complex residue of a polyol and boric acid. 3. An organic boron compound polymer has the formula (1): The adhesive composition according to claim 2, represented by: 4. The adhesive composition according to claim 1, wherein the organic boron compound polymer has a content of 100 parts by weight or less based on 100 parts by weight of the polyamide. 5. A thermal transfer recording medium in which a support, an adhesive layer, and an ink layer are sequentially laminated, wherein the adhesive layer is formed from the adhesive composition according to claim 1. Medium. 6. The thermal transfer recording medium according to claim 5, wherein the adhesive layer is formed from the adhesive composition according to claim 2. 7. The thermal transfer recording medium according to claim 5, wherein the adhesive layer is formed from the adhesive composition according to claim 3. 8. The thermal transfer recording medium according to claim 5, wherein the adhesive layer is formed from the adhesive composition according to claim 4.