JPH09277728A - Thermal transfer recording medium with heat resistant slipping layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide head-cleaning properties, prevent defects such as transfer blacking or the like, obtain superior heat-resisting property and heat-resistant slipping properties, and prevent a base material from being broken, etc., by using for a heat-resistant slippage layer a mixed body of a silicone modified cellulose resin and hydrophobic silica. SOLUTION: The thermal transfer recording medium is so formed that a thermal transfer layer 12 and a heat-resistant slippage layer 13 are provided at one face of a base material 11 and at the other face of the base material 11. The heat-resistant slippage layer 13 is formed of a mixed body of a silicone modified cellulose resin and hydrophobic silica continuously on the base material 11. The silicone modified cellulose resin is obtained by bonding long-chain silicone to a cellulose resin preferably by a ratio of 5-200% to secure fundamental performance. Although a particles shape of the hydrophobic silica is not particularly specified, a spherical shape without pores is preferred. Accordingly, the thermal transfer recording medium accompanies no transfer blanking due to dust adhering to the heat-resistant slippage layer 13.

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 for use in thermal transfer recording of characters, images, etc. using a thermal head, and in particular, it has a heat resistant slipping layer exhibiting excellent performance. It relates to a thermal transfer recording medium.

[0002]

2. Description of the Related Art A thermal transfer recording method is known in which a character or an image is formed by thermally transferring a thermal transfer layer formed on a substrate to a transfer target by using a thermal head. It is widely used at present because of its advantages such as low noise at the time, a color image can be formed relatively easily, and a thermal transfer recording apparatus itself for forming an image is compact and its cost is low. The thermal transfer recording system is generally classified into a melt transfer system and a sublimation dye system. First, in the former method, an ink layer in which a pigment is mixed with a low melting point substance such as wax is melt-transferred to a transfer target together with the ink layer by heat of a thermal head. In the latter, the ink layer is made by dispersing a sublimation dye in a polymer resin, the polymer resin is softened by the heat of the thermal head, and the sublimation dye uniformly dispersed therein is transferred by the heat of vaporization. It sublimates to the body.

Image formation is carried out by bringing a thermal head into close contact with the PET film from the side opposite to the ink layer of the PET film and transferring the ink layer to the transferred material by heating the thermal head. Since the surface of the thermal head momentarily reaches a high temperature of several hundred degrees, the PET film in contact with the thermal head is softened by the heat, sticking occurs, and eventually the film breaks. Therefore, the above-mentioned problem is solved by providing a heat resistant slipping layer capable of withstanding the heat of the thermal head on the surface of the PET film opposite to the ink surface. Most of the conventional heat resistant slipping layer is mainly a so-called hard coat, which is hard to be softened by heat of a thermal head such as a UV cured product, an EB cured product, and an isocyanate cured product, and is made of a part of a thermoplastic resin. Things also existed. Since the amount of heat of the thermal head varies depending on the type of thermal transfer recording material, its material is arbitrarily selected.

[0004]

However, the type of material of the heat resistant slipping layer mainly composed of UV cured material, so-called hard coat type, is excellent in heat resistance, but on the other hand, Dust and dust adhering to the heat resistant slipping layer adheres between the thermal head and the heat resistant slipping layer, causing defects such as omission of transfer in characters and images during transfer, that is, there is a tendency that there is no so-called head cleaning property. Yes, this is a problem. Further, the type of the material of the heat resistant slipping layer mainly composed of a thermoplastic resin tends to be different from the type described above, and since the heat resistance and lubricity of the resin itself are low, silicone oil, silicone By adding particles etc., it has a heat-resistant slip property. However, although this structure can prevent the transfer omission due to dust or dust,
It is fundamentally inferior in heat resistance and lacks heat-resistant slipperiness, which is the original function of objects that require a large amount of energy for image formation, and causes problems such as printing wrinkles, sticking, and rupture of the base material in severe objects. ing. Then, the added silicone oil bleeds over the surface with the passage of time and adheres to the ink surface, which may cause defective printing and decrease in smoothness, which is also a problem. .

The present invention has been made in view of the above problems of the conventional techniques, and is a thermal transfer recording medium having a thermal transfer layer on at least one side of a substrate and a heat resistant slipping layer on the other side. In addition, it is possible to prevent the occurrence of defects such as transfer drop by providing head cleaning property, and it is possible to prevent the occurrence of wrinkles and sticking of printing, the breakage of the base material, etc., which are excellent in heat resistance and heat resistance slipperiness, and moreover the silicone oil with the passage of time. It is an object of the present invention to provide a thermal transfer recording medium capable of preventing the occurrence of printing defects and the deterioration of slipperiness without causing bleeding on the surface and having these properties.

[0006]

[Means for Solving the Problems] Means provided by the present invention for solving the above-mentioned problems are as follows. First, as shown in claim 1, at least one surface of a base material has a thermal transfer layer and the other surface has heat-resistant lubricity. A thermal transfer recording medium provided with a layer, wherein the heat resistant slipping layer comprises a mixture of a silicone-modified cellulose resin and a hydrophobic silica. is there.

More preferably, the particle size of the hydrophobic silica in the heat resistant slipping layer is 10 to 10 as described in claim 2.
The thermal transfer recording medium with a heat-resistant slipping layer according to claim 1, which has a thickness of 50 μm.

More preferably, the content of the hydrophobic silica in the heat resistant slipping layer is 1 to 3 as described in claim 3.
It is 0%, It is a thermal transfer recording medium with a heat resistant slipping layer according to any one of claims 1 and 2.

<Operation> According to the present invention, the thermal transfer layer transfers the thermal transfer layer to an arbitrary transfer target by the thermal signal of the thermal head during the thermal transfer recording. When the heat-resistant layer is rubbed against the thermal head, dust and dirt attached to the heat-resistant slipping layer are attached to the surface of the heat-resistant slipping layer or so as to be buried in the heat-resistant slipping layer, and the dust-proof layer is carried along with the heat-resistant slipping layer. Since it is removed, it does not remain attached between the thermal head and the heat resistant slipping layer, and it is possible to prevent the occurrence of defects such as transfer defects. Further, it has been experimentally proved that the composition of the heat resistant slipping layer according to the present invention exhibits excellent heat resistance and heat resistant slipperiness even during use. Then, what used to function as a lubricant was silicone oil in the prior art, but in the present invention, the silicone-modified cellulose resin plays its role, so there is no free silicone, and the added silicone oil is There is no bleeding on the surface, there is no fear of causing print defects or deterioration of lubricity, and there is no fear of deterioration of printability even when stored at high temperature and high humidity.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the drawings. FIG. 1 is a sectional view of a thermal transfer recording medium of the present invention. The thermal transfer recording medium has a structure in which a thermal transfer layer (12) is provided on one side of a substrate (11) and a heat resistant slipping layer (13) is provided on the other side. The heat transfer layer can be provided with various layers of a single color, and is not limited to a single color, and by applying different colors to each other, it is possible to perform thermal recording of color display with rich expressiveness. I can. Further, as the thermal transfer layer, it is preferable to form a layer capable of transferring the receiving layer for the sublimable dye or a transferable protective layer in addition to the purpose of recording by color, and it is possible to appropriately design.

As the base material (11), the same material as that conventionally used as a base material of a thermal transfer recording medium can be used, and in consideration of mechanical toughness, flexibility, heat resistance and the like. It can be appropriately selected.

Specific examples of such a substrate (11) include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene, polyvinyl chloride, polycarbonate, polysulfane, polyimide, polyvinyl alcohol, aromatic polyamide, aramid. Examples thereof include plastic films such as films, paper base materials such as high-quality paper, coated paper and synthetic paper, and sheets obtained by combining these. Among them, a polyester film is preferred from the viewpoint of smoothness, strength, cost and the like. The thickness of the base material (11) is not particularly limited, but is generally 2 to 50 μm, preferably 3 to 12 μm in consideration of the transportability of the printer.

The thermal transfer layer (12) may be the same as the one used as a thermal transfer layer of a conventional thermal transfer recording medium, and is not particularly limited to a heat-meltable or a heat-sublimable transfer layer. . The thermal transfer layer (12) may be continuous or discontinuous on the substrate (11), but is not particularly limited.

The heat resistant slipping layer (13) is continuously formed on the substrate (11), but in the present invention, it is formed from a mixture of a silicone-modified cellulose resin and hydrophobic silica.

The silicone-modified cellulose resin, which is essential in the present invention, is a resin in which a long-chain silicone (siloxane chain) is bonded to the cellulose resin, and is provided with slipperiness without impairing the heat resistance inherent to cellulose. It is a resin. The ratio of the long-chain silicone to the cellulose resin varies depending on the application, but in general, it is 5 to 5 from the viewpoint of basic performance, printability, stability over time, surface strength, and lubricity. 200% is preferable, and it is 1 from the viewpoint that particularly high performance is obtained with these.
0-120% is good.

Regarding the hydrophobic silica mixed with the silicone-modified cellulose for the heat resistant slipping layer, the particle shape is not particularly limited in the present invention. However, although this hydrophobic silica is generally porous, it is more preferably spherical and has no pores. Naturally, it is preferably hydrophobic. In the present invention, if the particle diameter of this hydrophobic silica is less than 10 mμ, it has no cleaning property, and conversely, if it exceeds 50 mμ, the coefficient of friction with the thermal head becomes too high, causing defective running during printing. From these, in the present invention, the particle size is 10 to
50mμ is good. From the viewpoints of cleaning property, printability, stability over time, and ink dispersibility, in the present invention, when a particularly high effect is to be expected, the particle size is 10 to 20.
The case of being in the range of mμ is preferable. (Here, the particle diameter is defined as a value obtained by taking an electron micrograph of particles of 3000 to 5000 μm and averaging the respective diameters.)

Further, in the present invention, if the content of the hydrophobic silica in the resin is less than 1%, the expected performance cannot be exhibited, and conversely, if it exceeds 30%, the thermal head becomes a thermal head. The friction coefficient of is too high,
It is preferably from 1 to 30% because it causes a running defect during printing. Incidentally, 10 to 20% is more preferable. From the viewpoints of cleaning property, printing property, stability over time, ink dispersibility, etc., in the case of expecting a particularly high effect, in the present invention, it is preferable that the content is in the range of 10 to 20%. is there. (However, the content here is
All show weight%. )

Regarding the film thickness of the heat resistant slipping layer (13), in the present invention, in consideration of coating labor, easiness of drying, material cost saving, printing sensitivity, printing performance, etc., in general, The thickness is preferably about 0.1 to 2.0 μm, and further, from the aspect of the operation relating to the subject of the present invention, the cleaning property, the printing performance, and the printing property after storage, the thickness is 0.3 to 1.5 μm. More preferable.

[0019]

EXAMPLES First, all thermal transfer recording media were manufactured by the following method except for the heat resistant slipping layer. Thickness 4.5μm
On one side of the transparent polyethylene terephthalate film of, the coating solution of the following formulation was applied, and the total dry thickness was 1.5 μm.
Was gravure-coated to a thickness of to obtain a thermal transfer layer. [Heat transfer layer coating liquid] -Magenta dye 20 parts-Butyral resin 15 parts-Polyester resin 5 parts-Toluene 30 parts-Methyl ethyl ketone 30 parts

Next, regarding the heat resistant slipping layer, a coating solution corresponding to the following Examples 1 to 4 and Comparative Example 1 was gravure-coated to a dry thickness of 0.8 μm to obtain a heat resistant slipping property. Layered. As for the silicone-modified cellulose, a product in which 25 parts of long-chain silicone was bonded to 100 parts of cellulose was used.

<Example 1> [Heat resistant slipping layer coating liquid] -Silicone modified cellulose 15 parts-Hydrophobic silica (primary average particle diameter 25 μm) 0.15 parts-Toluene 60 parts-Methyl ethyl ketone 24.85 parts

<Example 2> [Heat resistant slipping layer coating liquid] -Silicone-modified cellulose 15 parts-Hydrophobic silica (primary average particle diameter 25 μm) 4.5 parts-Toluene 60 parts-Methyl ethyl ketone 20.5 parts

<Example 3> [Coating liquid for heat resistant slipping layer] • 15 parts of silicone modified cellulose • 3 parts of hydrophobic silica (primary average particle size 10 μm) • 60 parts of toluene • 22 parts of methyl ethyl ketone

<Example 4> [Coating liquid for heat resistant slipping layer] • 15 parts of silicone modified cellulose • 3 parts of hydrophobic silica (primary average particle size 50 μm) • 60 parts of toluene • 22 parts of methyl ethyl ketone

Hereinafter, a thermal transfer recording medium with a heat resistant slipping layer was prepared in the same manner as in the above example except for the matters specified in each comparative example. <Comparative Example 1> [Heat resistant slipping layer coating liquid] -Polyester (glass transition point 60 ° C) 20 parts-Silicone oil 2 parts-Toluene 60 parts-Methyl ethyl ketone 18 parts

<Comparative Example 2> [Coating liquid for heat resistant slipping layer] 20 parts of silicone modified cellulose 4 parts of silicone particles (average particle size 0.3 μm) 60 parts of toluene 16 parts of methyl ethyl ketone

Comparative Example 3 With respect to the heat resistant slipping layer, the following coating liquid was gravure coated as a whole, dried and irradiated with a UV lamp to obtain a heat resistant slipping layer having a dry thickness of 0.8 μm. [Heat resistant slipping layer coating liquid] Acrylic oligomer 50 parts Silicon powder 2 parts Silicon oil 5 parts Methyl alcohol 43 parts

<Examples 1 to 4> and <Comparative Examples 1 to 3>
Regarding each thermal transfer recording medium produced by
The heat resistant slipping layer was sprinkled with 3d × 1 mm polyethylene terephthalate powder, and the solid printing was performed using an Okura printing simulator with an energy of 1.0 mJ / dot. As a result, all the samples were printed normally.
(Here, 3d is a notation according to one notation indicating the size of powder.)

With respect to the printed matter using each thermal transfer recording medium of <Examples 1 to 4>, no streak-like transfer omission occurred at all, and when the state of the thermal head after printing was observed, polyethylene terephthalate powder adhered. It never happened. On the other hand, regarding the printed matter using the thermal transfer recording medium of <Comparative Example 1>, no streak-like transfer omission occurred at all, and when the state of the thermal head after printing was observed, polyethylene terephthalate powder adhered. I was never there. However, <Comparative Examples 2-3
In the case of>, streak-like transfer omission occurred from the beginning of printing, and it did not disappear at all. Observation of the state of the thermal head after printing revealed that polyethylene terephthalate powder was clearly attached to the thermocouple of the thermal head.

<Examples 1 to 4> and <Comparative example 1>
~ 3> each of the thermal transfer recording media is left in a wound state for 30 days under both room temperature condition (temperature 25 ° C, relative humidity 60%) and high temperature high humidity condition (temperature 40 ° C, relative humidity 90%). did. After that, in order to evaluate the result, 1.0m of each of these samples was obtained using the Okura printing simulator.
All solid printing was performed with an energy of J / dot.

Regarding the prints using the thermal transfer recording media according to <Examples 1 to 4> of the present invention, the printability after storage, whether in a room temperature environment or a high temperature and high humidity environment,
No wrinkles or sticking was observed, and it was possible to obtain a printed matter with no problems. On the other hand, in the case of <Comparative Example 1>, wrinkles and sticking occurred in the printability after storage at room temperature, high temperature and high humidity. still,
The samples of <Comparative Examples 2 to 3> have good results. Table 1 shows the above results.
In the table, ◯ means good, and x means bad.

[0032]

[Table 1]

[0033]

As described in detail above, according to the heat transfer recording medium with a heat resistant slipping layer according to the present invention, by using the heat resistant slipping layer having the above-mentioned composition, it is possible to adhere to the heat resistant slipping layer. It is possible to provide a thermal transfer recording medium in which transfer omission does not occur due to the influence of dust and dust that has been generated. Also, since the silicone oil is not the oil that acts as the lubricant, the silicone-modified cellulose resin prevents free silicone. In addition, since it is not necessary to worry about deterioration of printability even at high temperature and high humidity storage, the above-mentioned problem, that is, a thermal transfer recording medium in which at least one of the substrates is a thermal transfer layer and the other of the substrates is a heat resistant slipping layer. However, it is possible to prevent the occurrence of defects such as transfer dropouts by providing head cleaning properties, and it is also excellent in heat resistance and heat resistance slippage, sticking, or the occurrence of breakage of the substrate. It can be stopped, moreover that the silicone oil can be prevented from occurring bleeding or without printing occurs and lubricity decrease in defects in the surface over time, it is possible to provide a thermal transfer recording medium having these performances.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing the concept of an example of a thermal transfer recording medium with a heat resistant slipping layer according to the present invention, using a sectional view.

[Explanation of symbols]

 11 ... Substrate 12 ... Thermal transfer layer 13 ... Heat resistant slipping layer

Claims (3)

[Claims] 1. A thermal transfer recording medium having a thermal transfer layer on at least one side of a substrate and a heat resistant slip layer on the other side, wherein the heat resistant slip layer comprises a silicone-modified cellulose resin and a hydrophobic silica. A thermal transfer recording medium with a heat resistant slipping layer, wherein a mixture is used. 2. The thermal transfer recording medium with a heat resistant slipping layer according to claim 1, wherein the particle diameter of the hydrophobic silica in the heat resistant slipping layer is 10 to 50 μm. 3. The thermal transfer recording medium with a heat resistant slipping layer according to claim 1, wherein the content of the hydrophobic silica in the heat resistant slipping layer is 1 to 30%.