JPH05112081A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To provide a thermal transfer recording medium which is excellent in travelling performance in recording, can be easily manufactured in stable quality, and is excellent in stability of shelf life even in a wide range from comparatively low temperature to high temperature in heating temperature of a thermal head. CONSTITUTION:The subject thermal transfer recording medium is composed of a substrate 2 and a thermal transferring ink layer 3 provided on one side of the substrate. A back coat layer 1 containing at least two kinds of polymethacrylate ester of which glass transition temperatures are different from each other, urethane modified linear polyester, and lubricant is provided to the other side of the substrate to which the thermal transferring ink layer is not provided. Two kinds of polymethylmethacrylate of which glass transition temperatures are 68-90 deg.C and 90-105 deg.C should be preferably jointly used as polymethacrylic ester. Preferable urethane modified linear polyester should be at most 65 deg.C in glass transition temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium. More specifically, the present invention relates to a thermal transfer recording medium for transferring and recording an image or the like on a transfer target using a thermal head, which is excellent in running property during recording, easy to manufacture and stable in quality. Regarding

[0002]

2. Description of the Related Art In recent years, as an image recording method for word processors, video printers and the like, a thermal transfer recording medium having a thermal transfer ink layer provided on one side of a film-like substrate made of PET film or the like is heated by a thermal head to produce recording paper. A thermal transfer recording method for transferring and recording an image on a transfer target such as a recording medium is widely used.

In such a thermal transfer recording method, a material to be transferred such as recording paper is arranged on the thermal transfer ink layer side of the thermal transfer recording medium, and the surface of the thermal transfer recording medium on which the thermal transfer ink layer is not provided is thermally transferred. While making contact with the thermal pad of the recording device and maintaining the contact state, the material to be transferred and the thermal transfer recording medium are moved relative to the thermal head, while the thermal head is heated according to the print information to perform thermal transfer. Transfers the ink of the functional ink layer to the transfer material.

Therefore, as a conventional thermal transfer recording medium,
On the surface of the film-shaped substrate on which the thermal transfer ink layer is not formed, heat resistance against heating by a thermal head,
In order to improve the running property with respect to the contact movement with the thermal head, a ribbon-shaped recording medium having a heat-resistant, slippery back coat layer formed thereon is often used.

As such a back coat layer, a layer is formed of a heat resistant plastic resin such as an aromatic polyamide resin or a heat or radiation curable resin such as a phenol resin or a melamine resin, and the layer is formed as necessary. An inorganic heat-resistant substance such as colloidal silica may be further added, and a surfactant such as phosphoric acid ester or a lubricant such as silicone oil may be added to such a layer in order to improve the slip property. The resin forming the coat layer has been modified with silicone.

[0006]

However, when a heat resistant plastic resin is used as the back coat layer of the thermal transfer recording medium, there is no resin satisfying both the heat resistance and the adhesiveness to the substrate, There were problems such as poor heat resistance and poor adhesion. Further, when a lubricant such as silicone oil is used, there is a problem that oil migration is likely to occur.

Further, when a curable resin is used as the back coat layer, special processing conditions such as high temperature treatment, aging treatment, ultraviolet ray and electron beam irradiation and an apparatus therefor are required at the time of layer formation. There is a problem with the manufacturing facility, and because the material is a reactive resin, it is not easy to store and manage the material, and the reproducibility of the cured state of the backcoat layer is insufficient, so the quality of the backcoat layer itself is stable. However, there has been a problem that the lubricity of the surface changes, especially when the lubricant such as silicone oil is added, the surface lubricity changes.

Further, the conventional thermal transfer recording medium has a wax type thermal transferable ink layer for printing by heating the thermal head at a relatively low temperature, and thermal sublimation for printing by heating at a relatively high temperature. Some have a thermal transfer ink layer of a type using a functional dye, but the conventional back coat layer has a problem that it cannot be applied to both types of thermal transfer recording media.

The present invention is intended to solve the above problems in the prior art, and even when the heating temperature of the thermal head is performed in a wide recording energy range from a relatively low temperature to a high temperature. It is an object of the present invention to provide a thermal transfer recording medium which has excellent running properties during recording, can be easily manufactured with stable quality, and has excellent storage stability.

[0010]

In order to achieve the above-mentioned object, the present invention comprises a substrate and a heat transferable ink layer provided on one side of the substrate, and a thermal transferable ink layer using a thermal head. In a heat-sensitive transfer recording medium for transferring the above ink to a transfer material, at least two kinds of polyacrylic acid ester or polymethacrylic acid having different glass transition temperatures are provided on the surface of the substrate on which the heat transferable ink layer is not provided. Provided is a thermal transfer recording medium comprising a back coat layer containing an acid ester (abbreviated as poly (meth) acrylic acid ester in the present specification), a urethane-modified linear polyester and a lubricant.

The thermal transfer storage medium of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a thermal transfer recording medium according to a preferred embodiment of the present invention. In the figure, a back coat layer 1 is provided on a base material 2, and a thermal transferable ink layer 3 is provided on the surface of the base material 2 opposite to the back coat layer 1.

The back coat layer 1 contains at least two kinds of poly (meth) acrylic acid esters having different glass transition temperatures, a urethane-modified linear polyester and a lubricant.

As the poly (meth) acrylic acid ester used in the present invention, polymethacrylic acid ester can be preferably used from the viewpoint of deformability, and methyl polymethacrylate can be particularly preferably used. The poly (meth) acrylic acid ester used in the present invention has a glass transition temperature in the range of 68 ° C to 105 ° C. When a glass transition temperature of less than 68 ° C. is used, heat resistance of the back coat layer is insufficient, resulting in abnormalities such as sticking during recording, and a glass transition temperature of more than 105 ° C. is used. In this case, it is difficult not only to make the resin solution for forming the backcoat layer into a desired concentration, but also to reduce the adhesion between the backcoat layer 1 and the substrate 2 and curl of the recording medium itself. Occurs.

Further, when only the poly (meth) acrylic acid ester having a glass transition temperature of 68 ° C. to 90 ° C. is used, a recording energy of a comparatively high recording energy such as that applied to a repetitive recording ribbon or a sublimation transfer ribbon is obtained. In the case of high heating of the thermal head, abnormalities such as sticking and cutting of the ribbon are likely to occur during recording due to insufficient heat resistance of the back coat layer, and the glass transition temperature is 90 ° C to 1 ° C.
When only the one having a temperature of 05 ° C. is used, in the case of heating a thermal head having a relatively low recording energy, which is performed for a transfer ribbon having a wax type thermal transferable ink layer, poly (meth) acrylic acid is used at the time of recording. Since the ester is not sufficiently softened, a lubricant such as silicone oil described later does not function effectively on the surface of the back coat layer, and as a result, abnormalities such as sticking are likely to occur.

Therefore, in the present invention, the glass transition temperature of the poly (meth) acrylic acid ester is 68 ° C to 90 ° C.
It is preferable to use a mixture of one with 90 ° C. to 105 ° C. for use.

As described above, in the present invention, at least two kinds of poly (meth) acrylic acid esters having different glass transition temperatures are used, but it is preferable that the glass transition temperatures between the two are separated to some extent. The difference is 5
The temperature is 35 ° C, preferably 10 to 35 ° C.

The blending ratio of poly (meth) acrylic acid esters having different glass transition temperatures varies depending on the recording apparatus and recording conditions. For example, the glass transition temperature is 68.
Generally, the compounding ratio of the poly (meth) acrylic acid ester having a glass transition temperature of 90 ° C. to 105 ° C. and the poly (meth) acrylic acid ester having a temperature of 90 ° C. to 90 ° C. is preferably 7: 3 to 3: 7. Further, the proportion of the poly (meth) acrylic acid ester as a whole in the backcoat layer 1 is preferably 5
It is 0 to 99% by weight, more preferably 80 to 95% by weight.

The urethane-modified linear polyester is used for improving the adhesion of the back coat layer 1 containing the above-mentioned poly (meth) acrylic acid ester to the substrate 2. In particular, when a general polyethylene terephthalate film is used as the substrate 2, the adhesiveness is remarkably improved. As such a urethane-modified linear polyester, one having a glass transition temperature of 65 ° C. or lower is preferable. When the temperature exceeds 65 ° C, the adhesion to the base material 2 is reduced.

The proportion of the urethane-modified linear polyester compounded in the back coat layer is preferably 0.5 to 35% by weight, more preferably 1.0 to 20% by weight. However,
The proportion preferably does not exceed the proportion of the entire poly (meth) acrylic acid ester. More preferably, the ratio of the urethane-modified linear polyester to the total poly (meth) acrylic acid ester is 35:65 to 5:95.

The lubricant is used for imparting lubricity to the back coat layer 1. Examples of such a lubricant include silicone oil and the like. The mixing ratio of the lubricant to the back coat layer 1 varies depending on the kind of the lubricant and the like, but, for example, in the case of silicone oil, preferably 1 to 3
It is 0% by weight, more preferably 3 to 15% by weight.

The thickness of the back coat layer 1 varies depending on the blending ratio of the above-mentioned components, recording conditions and the like, but is preferably 0.1 to 0.6 μm.

When the back coat layer 1 is constituted from the above components, the back coat layer can be easily formed with a constant quality and the storage stability thereof is excellent.

In the thermal transfer recording medium of the present invention, the layer constitution other than the above-mentioned back coat layer can be the same as the conventional example. That is, as the base material 2 used in the present invention, a plastic film such as a polyester film, a polystyrene film, a polysulfone film, a polyimide film, a polyvinyl alcohol film, an aromatic polyamide film, an aramid film, or a thin paper such as cellophane or condenser paper. A substrate generally used for a thermal transfer recording medium can be used as appropriate according to the purpose of use. In particular, a polyester film having a thickness of 3 to 8 μm can be preferably used.

Further, the thermal transferable ink layer 3 used in the present invention is formed from an ink in which various dyes such as sublimable dyes and heat-fusible dyes, or coloring materials such as carbon black and other pigments are mixed with a binder. Those conventionally used for thermal transfer recording media such as those described above can be appropriately used according to the purpose of use. For example, as the dye used for the thermal transferable ink layer 3, diarylmethane-based dyes, triarylmethane-based dyes, thiazole-based dyes, methine-based dyes,
Widely used commonly used dyes such as azomethane type, xanthene type, axazine type, thiazine type, azine type, acridine type, azo type, spirodipyran type, isodino spiropyran type, fluorane type, rhodamine dactam type, anthraquinone type can do. As the binder, wax, vinyl acetal resin, polyester resin, cellulose resin, acrylic resin, polyamide resin or the like can be used. In addition to the above, the thermal transferable ink layer 3 may appropriately contain a surfactant, a softening agent, an additive, and the like. The layer thickness of the thermal transferable ink layer 3 is
It depends on the ink composition and recording conditions, but preferably 2
The thermal transfer recording medium of the present invention having a thickness of 9 μm can be produced by a conventional method. For example, a heat transferable ink composed of a heat sublimable dye, a binder resin and a solvent is applied to the surface of the base material 2 using a gravure coater or the like, and dried,
The heat transferable ink layer 3 is formed, and then the composition for the back coat layer is applied to the back surface of the substrate 2 coated with the heat transferable ink layer 3 and dried to form the back coat layer 1. A thermal transfer recording medium can be manufactured.

The thermal transfer recording medium of the present invention can be applied not only to a recording apparatus using a thermal head as a heating unit for transfer, but also to a recording apparatus using an infrared ray or a laser beam as a heating unit.

[0027]

In the thermal transfer recording medium of the present invention, since at least two kinds of poly (meth) acrylic acid esters having different glass transition temperatures are used for the back coat layer, the heating temperature of the thermal head is relatively high. Even when performed in a wide range of recording energies from low temperature to high temperature, it is possible to improve runnability during recording, and since urethane-modified linear polyester is compounded, it is possible to use a back coat layer and a base layer. It is possible to improve the adhesiveness with the material, and further, since a lubricant is mixed, it is possible to improve the lubricity of the back coat layer.

Further, since the components blended in these back coat layers are excellent in processability and storage stability, it is possible to manufacture a thermal transfer recording medium having a constant quality and good storage stability.

[0029]

EXAMPLES The present invention will be described below in greater detail by giving Examples.

Example 1 On one side of a stretched polyester film having a thickness of 3.5 μm,
Polymethylmethacrylate 35 with glass transition temperature of 75 ° C
% By weight, 35% by weight of polymethylmethacrylate having a glass transition temperature of 105.degree. C., 21% by weight of urethane-modified linear polyester having a glass transition temperature of 45.degree. ．
A thermal transferable ink layer (thickness: 4.0 μm) containing a wax having a melting point of 68 ° C. and carbon black as main components, and having a thickness of 4.0 μm.
m) was provided to produce the thermal transfer recording medium A of the present invention.

This recording medium A 100 meters is 12.7
After cutting it to a width of mm, winding it around a bobbin, mounting it on a ribbon cassette for a serial printer, and leaving it for 96 hours in an environment with an ambient temperature of 50 ° C, 320 DPI, printing speed 5
0 characters / sec. Printing energy was printed in three stages of low, medium, and high using the serial printer of No. 3. As a result, in the case of printing before leaving, no trouble occurred in the running property of the recording medium and the printed image over the entire length of the recording medium at any printing energy level. Also, in the case of printing after being left unattended, no abnormality was found at any energy printing.

The coefficient of friction of the contact surface of the recording medium A that contacts the thermal head was measured for an ABS resin having the same coefficient of friction as the material of the cassette. As a result, the friction coefficient of the recording medium A was 0.20 before being left, and it was 0.22 after being left.

Comparative Example 1 For comparison, the film-shaped substrate and the heat transferable ink layer were the same, but 70% by weight of polymethylmethacrylate having a glass transition temperature of 75 ° C. and a glass transition temperature of 45 ° C. were formed on the back surface of the ink layer. A thermal transfer recording medium B for comparison was manufactured by forming a composition for a back coat layer consisting of 21% by weight of urethane-modified linear polyester and 9% by weight of silicone oil so as to have a dry film thickness of 0.3 μm.

The same test as in Example 1 was carried out. As a result, sticking occurred in high energy printing, and holes were formed in the base polyester film. The friction coefficient before leaving was 0.21, but that after leaving was significantly increased to 0.34.

Comparative Example 2 A thermal transfer recording medium C was manufactured by repeating Comparative Example 1 except that polymethyl methacrylate having a glass transition temperature of 105 ° C. was used instead of polymethyl methacrylate having a glass transition temperature of 75 ° C.

As a result of performing the same test as in Example 1, a composition for a back coat layer, in which sticking occurs in low energy printing, abnormal noise occurs, and unevenness in image density is caused, a dry film thickness of 0. A thermal transfer recording medium B for comparison was manufactured by forming the thermal transfer recording medium B so as to have a thickness of 3 μm on the substrate.

Comparative Example 3 A thermal transfer recording medium D was formed by forming a back coat layer containing 91% by weight of nitrocellulose and 9% by weight of silicone oil on a substrate. When the same test as in Example 1 was conducted, an abnormal sound was generated and unevenness in the density of the image was generated at any energy level.

[0038]

According to the present invention, even when the heating temperature of the thermal head is carried out in a wide range of recording energy from a relatively low temperature to a high temperature, the running property during recording is excellent and the quality is stable. A thermal transfer recording medium that can be easily manufactured and has excellent storage stability can be provided.

[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 back coat layer 2 film substrate 3 thermal transfer ink layer

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[Procedure amendment]

[Submission date] September 17, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (2)

[Claims] 1. A thermal transfer recording medium comprising a base material and a heat transferable ink layer provided on one surface of the base material, wherein the ink of the heat transferable ink layer is transferred to a transfer target material by using a thermal head. On the surface on which the thermal transferable ink layer is not provided, a back coat layer containing at least two kinds of poly (meth) acrylic acid ester having different glass transition temperatures, a urethane-modified linear polyester and a lubricant is provided. Characteristic thermal transfer recording medium. 2. One of the at least two poly (meth) acrylic acid esters is polymethylmethacrylate having a glass transition temperature of 68 ° C. to 90 ° C., and the other is polymethylmethacrylate having a glass transition temperature of 90 ° C. to 105 ° C. The thermal transfer recording medium according to claim 1, wherein the thermal transfer recording medium is methacrylate and the urethane-modified linear polyester has a glass transition temperature of 65 ° C or lower.