JP2001334752A - Manufacturing method for thermal transfer recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to manufacture a thermal transfer recording medium having two or more layers formed by superposing a heat melting layer on a base, wherein the heat melting layers can be formed without mixing with each other and each layer can display its proper function when a heat melting layer after the second heat melting layer is to be formed by a hot melt coating method. SOLUTION: In the method for manufacturing the thermal transfer recording medium having two or more heat melt layers layered therein, the second heat melt layer is formed on the first heat melt layer by the hot melt coating method wherein at least a support side heating medium roll, a coating side heating medium and a coating agent tank are used. The temperature of the support side heating medium roll is made to be the melting point or lower of the first heat melt layer, and the temperature of the coating side heating medium roll and the coating agent tank is set to a temperature range higher than the melting point of the second heat melt layer by 0-30 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a thermal transfer recording medium. More particularly, the present invention relates to an improvement in a case where a heat-sensitive transfer recording medium having two or more heat-melting layers stacked on each other is manufactured by a hot-melt gravure coating method.

[0002]

2. Description of the Related Art With the rapid development of the information industry in recent years, various recording methods and recording apparatuses suitable for various information processing systems have been developed. Among them, the thermal recording method has a compact apparatus. It has been widely used because of no noise, excellent operability and maintainability. Among the heat-sensitive recording methods, the method using a heat-sensitive transfer recording medium heats a hot-melt ink layer of the heat-sensitive transfer recording medium with a heat source such as a thermal head, and melts a part of the hot-melt ink layer as a transfer pattern. This is a method in which recording is performed by transferring to a transfer material such as plain paper or a tag. This type of thermal transfer recording medium is used in barcode printing machines, facsimile machines, ticketing machines such as tickets and commuter passes, and general thermal recording devices such as word processor ribbons.

A typical conventional thermal transfer recording medium has a layer structure in which two or more heat-melting layers are provided on one surface of a substrate and a heat-resistant protective layer is provided on the other surface of the substrate. ing. The reason why two or more layers are provided is as follows. That is, if there is only one heat-melting layer, the main purpose is to inevitably color the layer. (1) This layer comes into direct contact with a transfer object such as paper, and so-called smudge stain is removed. (2) When printing on paper or the like having large irregularities on the surface, so-called voids (white spots) are generated, and the print quality cannot be secured. (3) Sufficient adhesiveness to the transfer receiving body cannot be secured. 4) In the case of a roll ribbon type product, the surface of this layer adheres to an adjacent substrate surface during storage at a high temperature or the like, so-called blocking phenomenon easily occurs. (5) Peeling from the substrate (6) Insufficient heat transfer sensitivity, insufficient thermal transfer sensitivity, and (6) insufficient print clarity.

Therefore, generally, from the viewpoint of functional separation, at least one heat-melting layer is further provided, and the layer has a function for solving and preventing the above-mentioned problem.

Various methods have been conventionally proposed for producing such a thermal transfer recording medium provided with at least two heat-melting layers. One of them is a first heat-melting layer. There is a method of forming by applying by a solvent method such as gravure or Meyer bar or by a hot melt method, and forming the second hot melt layer by applying by a hot melt method. FIG. 1 shows a typical example of a gravure coater conventionally used when a second hot melt layer is formed on a first hot melt layer by a hot melt gravure coating method.
Shown in The apparatus includes a support-side heat medium roll including a backup roll 11, a coating-side heat medium roll including a print roll 13 and a gravure roll 14, a coating agent tank 15 such as an ink pan, and a vibrating doctor 16. Offset gravure coater. Conventionally, when forming the second heat-melted layer, the coating-side heat transfer medium roll including the print roll 13 and the gravure roll 14 and the coating agent tank 15 are generally 40 points higher than the melting point of the second heat-melted layer. The temperature is controlled to be higher by about 80 ° C., and the supporting-side heat medium roll including the backup roll 11 is also controlled to be higher than the melting point of the first heat-melted layer. This is because if the temperature of the coating agent tank and various rolls is lowered, the melt viscosity of the coating agent increases and the coating amount increases, so it is difficult to control the coating amount. If the temperature of the roll is too low, the hot-melt coating agent solidifies, causing coating unevenness and making it impossible to perform coating itself. Therefore, the above temperature setting is used.

However, in the conventional method using the temperature control,
When the second hot melt layer is applied by the hot melt gravure coating method, the first hot melt layer formed earlier is melted by heating by the backup roll, and as a result, the first hot melt layer is melted.
The heat-melted layer and the second heat-melted layer are mixed with each other, and as a result, there is a disadvantage that the original function of each layer cannot be sufficiently exhibited. Also, if the temperature of the coating-side heating medium roll is too high, the first heat-melted layer and the second heat-melted layer are also mixed with each other,
A similar problem occurred.

[0007]

Therefore, in the present invention,
When manufacturing a thermal transfer recording medium having two or more layers formed by laminating a heat-melting layer on a base material, when the second and subsequent layers of the heat-melting layer are formed by a hot melt coating method, the heat transfer of these two or more layers is performed. It is not possible to realize a method of manufacturing a thermal transfer recording medium in which a molten layer can be formed without mixing the layers with each other, and as a result, each layer can sufficiently perform its original function. .

[0008]

In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a heat-sensitive transfer recording medium in which a heat-melting layer is provided on a substrate by providing two or more layers. In forming the second heat-melting layer on the layer by at least a hot-melt coating method using a support-side heat medium roll, a coating-side heat medium roll, and a coating agent tank, the temperature of the support-side heat medium roll is reduced to a second value. The temperature of the coating-side heating medium roll and the coating material tank are set to a temperature range that is 0 to 30 ° C. higher than the melting point of the second heat melting layer.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention can be carried out as follows to produce a thermal transfer recording medium.
FIG. 2 shows a typical example of the layer structure of the thermal transfer recording medium manufactured according to the present invention.

A heat-resistant protective layer 24 is formed on one surface of a substrate 21 of a thermal transfer recording medium by a solvent coating method using a conventionally employed gravure or Meyer bar. On the other surface of the base material, a first heat melting layer 22 is provided by coating using a solvent method such as gravure or Meyer bar or a hot melt method.

Next, a second heat melting layer 23 is formed on the first heat melting layer 22 by the method of the present invention. That is,
The second hot melt layer 23 is formed by a hot melt coating method under strict temperature control. The hot melt coating method includes an offset coating method, an offset gravure coating method, a direct gravure coating method, and a reverse coating method, and the offset gravure coating method is particularly preferable. FIG. 1 shows a typical configuration example of an offset gravure coater used in the offset gravure coating method. In the offset coating method, at least a backup roll is used as a support-side heating medium roll, and at least a print roll and a pickup roll are used as a coating-side heating medium roll. In the offset gravure coating method, at least a backup roll is used as a support-side heat medium roll, and at least a print roll and a gravure roll are used as a coating-side heat medium roll. The configuration example shown in FIG. 1 is a representative example,
The configuration can be changed as desired. For example, a heating medium roll may be further added to stabilize the coating. In the direct gravure coating method, at least a backup roll is used as a support-side heat medium roll, and a gravure roll having at least a print roll function is used as a coating-side heat medium roll. Further, the reverse coating method, in the offset coating method, the offset gravure coating method, or the direct gravure coating method, the coating-side heating medium roll in contact with the substrate, rotating in the direction opposite to the direction of travel of the substrate. This is the method of coating.

When forming the second hot melt layer 23, the temperature of each roll of the gravure coater is strictly controlled. More specifically, the backup roll 11 as a support-side heat carrier roll
Is set to be equal to or lower than the melting point of the first heat melting layer. How low the temperature range is controlled greatly depends on the characteristics of the coating agent such as ink, coating speed, etc.
The temperature is controlled to an optimum temperature between 0 and 30 ° C. lower than the melting point of the hot-melt layer 22 in consideration of coatability, ribbon performance, and the like. When the temperature of the backup roll 11 is set higher than the melting point of the first hot melt layer, the constituent material of the first hot melt layer is melted and mixed with the constituent material of the second hot melt layer, The object of the present invention cannot be achieved. On the other hand, if the temperature of the backup roll 11 is set to be lower than the above-mentioned optimum temperature, the constituent material of the first heat-melted layer that has been hot-melted starts to solidify, and as a result, the amount of application is controlled. Or it may cause uneven coating.

The temperature of a coating agent tank 15 such as an ink pan containing the second coating material for forming a hot-melt layer, and the temperature of the heating medium roll on the coating side of the print roll 13 and the gravure roll 14 are as follows: The temperature is controlled to be 0 to 30 ° C. higher than the melting point of the second heat melting layer, preferably 5 to 20 ° C. higher. If these temperatures are set lower than the melting point of the second hot-melt layer, the coating cannot be applied because the coating agent does not melt. On the other hand, when these temperatures are set higher than the melting point of the second heat-melting layer by more than 30 ° C., the first heat-melting layer already formed starts to melt, and as a result, the first heat-melting layer 22 and the second heat-melted layer 23 are mixed.

In the above, the temperature control in the case where the second hot melt layer 23 is formed by the offset gravure coating method using the offset gravure coater shown in FIG. 2 has been described. Also, the configuration of the heating medium roll on the coating side is different, but the temperature of the support side heating medium roll, the coating side heating medium roll and the coating agent tank are controlled similarly to the offset gravure coating method. Specifically, in the case of the offset coating method, the temperature of the backup roll constituting the support-side heat medium roll is set to be equal to or lower than the melting point of the first heat-melting layer, and the printing forming the coating-side heat medium roll is performed. The temperature of the roll, the pickup roll, and the coating agent tank is controlled to a temperature higher by 0 to 30 ° C. than the melting point of the second hot-melt layer, preferably to a temperature higher by 5 to 20 ° C. In the case of the direct gravure coating method, the temperature of the backup roll constituting the support-side heat medium roll is set to be equal to or lower than the melting point of the first heat-melted layer, and the gravure roll constituting the coating-side heat medium roll, and The temperature of the work tank is 0 to 30 from the melting point of the second hot melt layer.
The temperature is controlled to be higher by 5 ° C, preferably 5 to 20 ° C. In the case of the reverse coating method, the temperature of the support-side heating medium roll is set to be equal to or lower than the melting point of the first hot-melt layer, similarly to the above-described offset coating method, offset gravure coating method, or direct gravure coating method. , The temperature of the coating-side heating medium roll and the coating agent tank to a temperature higher by 0 to 30 ° C. than the melting point of the second hot melt layer,
Preferably, the temperature is controlled to be higher by 5 to 20 ° C.

As the substrate 21 used in the present invention, a polyester resin, especially polyethylene terephthalate (PE) is used.
T), a plastic sheet such as a polypropylene resin, a polycarbonate resin, a cellophane, a polyethylene resin and a polyimide resin, or papers such as a condenser paper and a paraffin paper can be used. The thickness of the substrate 21 is preferably 3 to 20 μm.

The heat-resistant protective layer 24 is formed from a silicone resin or from heat-resistant particles such as inorganic particles or curable resin particles and a binder resin. Generally, the coating amount of the heat-resistant protective layer is preferably 0.05 to ² g / m ² .

The release layer, which can be provided as required, can be formed by applying various kinds of waxes or a mixture thereof with a binder resin and a filler. Examples of waxes include carnauba wax, candelilla wax, rice wax, montan wax, paraffin wax, microcrystalline wax, polyethylene wax, ester wax, oxidized wax, and Fischer-Tropsch wax (Sazol wax). As the binder resin, ethylene-vinyl acetate copolymer, ethylene-ethyl acryl copolymer, polyvinyl alcohol, various rubbers, low-molecular polyamide resin, polyester resin, low-molecular polyalkylene such as polyethylene and polypropylene, styrene, butyral Resin and vinyl chloride resin. Examples of the filler include inorganic or organic fillers such as silica, calcium carbonate, carbon black, silicone-based copolymer elastomer, and cured particles of melamine resin. The release layer is generally from 0.05 to
5 g / m ^2, preferably formed at a coverage of from 0.1 to 2.0 g / m ^2.

The first heat melting layer 22 has a function of either a peeling layer or a coloring layer. When the first heat melting layer 22 functions as a release layer, it is not necessary to separately provide the release layer as described above. Further, the second heat melting layer 23 is
It functions as either a colored layer or various functional layers.

When the first heat melting layer 22 or the second heat melting layer 23 functions as a coloring layer, these heat melting layers are formed from various coloring agents, waxes, resins and the like. Examples of the colorant include black pigments or dyes such as carbon black and oil black, cyan, magenta, and yellow pigments and dyes.From these colorants, depending on the field of application or purpose of use of the thermal transfer recording medium, You can choose. As waxes,
Carnauba wax, candelilla wax, rice wax, montan wax, paraffin wax, microcrystalline wax, polyethylene wax, ester wax, oxidized wax, and Fischer-Tropsch wax (Sazol wax). Examples of the resins include an ethylene / vinyl acetate copolymer, a styrene-butadiene copolymer, a polyester resin, an epoxy resin, a rosin derivative, a terpene derivative, and a styrene-based resin. The coating amount of the colored layer is generally 0.5 to 10 g / m ² , preferably 2 to 6 g / m ² .
m ² .

When the first heat melting layer 22 or the second heat melting layer 23 is made to function as the functional layer, various materials such as waxes, resins, fillers, pigments and the like may be used according to the purpose. It is appropriately selected from dyes and used.

In the present invention, one of the first heat-melting layer 22 and the second heat-melting layer 23 must be a colored layer in order to fulfill its essential function as a thermal transfer recording medium. When the heat melting layer 22 is a colored layer, the second
It is preferred that the heat-melted layer 23 be a functional layer for the purpose of improving the clarity of printing or the adhesiveness to the material to be transferred. In this configuration, the first heat-melted layer 22 is a layer to be transferred to the transfer material, and this layer forms a transfer pattern. When the first heat melting layer 22 is used as a release layer, the second heat melting layer 23 is used as a coloring layer. In this configuration, the second heat-melted layer 23 is transferred to the transfer material to form a transfer pattern. If desired, both the hot melt layers 22 and 23 may be colored layers.

In the above, the thermal transfer recording medium having two heat-melting layers has been described. However, the production method of the present invention is also effective for producing a thermal transfer recording medium having three or more heat-melting layers. For example, three heat-melting layers can be formed as a release layer, a coloring layer, and a functional layer on the surface of the substrate 21 opposite to the heat-resistant protective layer 24. Even in the case of manufacturing a thermal transfer recording medium having such a configuration, it is possible to prevent the thermal fusion layers from being mixed with each other when forming each thermal fusion layer. The original functions possessed can be fully exhibited.

[0023]

Example 1 A solution of the following composition (1) was applied to one surface of a polyethylene terephthalate (PET) film having a thickness of 6 μm by a gravure method at a ratio of an application amount of 0.2 g / m ² , After drying, a heat-resistant protective layer was formed. Composition (1): 20 parts by weight of silicone resin (Dialomer SP712 manufactured by Dainichi Seika Kogyo Kogyo Co., Ltd.) 80 parts by weight of methyl ethyl ketone Then, the other surface of the polyethylene terephthalate film was coated with a solution of the following composition (2) by gravure at a rate of 0.5 g / It was applied at a ratio of m ² and dried to form a release layer. Composition (2): 1.7 parts by weight of polyester resin 1.7 parts by weight of vinyl chloride resin 3.5 parts by weight of polyethylene wax 3.5 parts by weight of melamine resin 0.1 part by weight Toluene 46.5 parts by weight Methyl ethyl ketone 46.5 parts by weight 1. A hot-melt coating composition having the following composition (3) was placed on the release layer.
Hot melt coating was performed so as to have an application amount of 0 g / m ² to form a first hot-melt layer as a colored layer. Composition (3): (melting point: 70 ° C.) Candelilla wax (Candelilla No. 1 made by Nippon Wax) 35 parts by weight Paraffin wax (HNP-9 made by Nippon Seiwa) 40 parts by weight Ethylene vinyl acetate copolymer (Mitsui DuPont) EVA310) 5 parts by weight Terpene phenol copolymer (YS Polystar T115 manufactured by Yasuhara Chemical) 5 parts by weight Carbon black (PRINTEX25 manufactured by Degussa) 15 parts by weight A hot-melt coating of the following composition (4) is applied on the first heat-melted layer. Coating speed 1 so that the amount of the coating agent is 0.5 g / m ^2.
Hot melt coating was performed at 00 m / min to form a second hot-melt layer as a functional layer. Composition (4): (melting point: 80 ° C.) Carnauba wax (Carnava No. 1 made by Nippon Wax) 80 parts by weight Terpene phenol copolymer (YS Polystar T115 manufactured by Yashara Chemical) 10 parts by weight Carbon black (PRINTEX25 manufactured by Degussa) 10 parts by weight

At this time, a second hot melt layer was formed using an offset gravure coater. The melting point of the first heat melting layer was 70 ° C, and the melting point of the second heat melting layer was 80 ° C. The temperature of the backup roll of the offset gravure coater was set to 60 ° C., and the temperatures of the ink pan, gravure roll, and print roll as a coating agent tank for holding the second hot melt layer coating agent were controlled to 90 ° C.

With respect to the thermal transfer recording medium thus obtained,
From the viewpoint of print clarity and print density, evaluation was performed as follows. Table 1 shows the evaluation results.

The print clarity was visually evaluated using a Zebra Xi-140 on the printed thermal transfer recording medium in five steps. The higher the grade, the better the print clarity.

The printing density was evaluated for the printed thermal transfer recording medium using a Macbeth densitometer RD918. In addition, the coating property of the coating agent of the second hot melt layer was also evaluated. Table 1 shows the results.

Examples 2 to 3 and Comparative Examples 1 to 5 When hot-melt coating the second heat-melting layer as a functional layer, the temperature of the backup roll of the offset gravure coater, the temperature of the coating agent tank (ink pan), A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the temperatures of the gravure roll and the print roll were controlled to the temperatures shown in Table 1. The thermal transfer recording medium thus obtained was evaluated in the same manner as in Example 1. These evaluation results are summarized in Table 1.

[0029]

[Table 1]

Coatability: ○ No problem △ Although coating is possible, it is difficult to control the amount of coating, and there are also problems such as uneven coating. × Coating not possible Print sharpness: * Adverse effect on print sharpness due to poor coatability of second hot melt layer (evaluation ①)

[0031]

In the above embodiment, the first heat-melting layer is provided as a colored layer, and the second heat-melting layer is formed as a functional layer whose main purpose is to improve the clarity of printing. However, the thermal transfer recording medium according to the method of the present invention was significantly improved particularly in print clarity as compared with the thermal transfer recording medium according to the comparative example which is a conventional method.

[0032]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an offset gravure coater that can be used in the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing a typical layer structure of a thermal transfer recording medium obtainable by the production method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Backup roll 12 ... Thermal transfer recording medium base material which has a 1st heat melting layer 13 ... Print roll 14 ... Gravure roll 15 ... Coating agent tank 16 ... Vibration Doctor 21: base material 22: first heat melting layer 23: second heat melting layer 24: heat-resistant protective layer

Continuation of the front page (72) Inventor Bunse Sentence 2-15-20 Chuo, Joto-ku, Osaka-shi, Osaka Inside General Co., Ltd. (72) Inventor Yoshikazu Ishihara 2-15-20 Chuo, Joto-ku, Osaka-shi, Osaka General term F term (reference) 2C068 AA06 BB18 BD19 2H111 AA14 AA16 AA17 AA26 BA03 BA12 DA01 4D075 AC23 AC26 AC28 AC72 AC96 DA04 DC27 4F040 AA22 AB02 AC01 BA24 BA25 CB15 CB21 CB23 CB33 DA16

Claims (6)

[Claims] 1. A method for producing a thermal transfer recording medium comprising a heat-melting layer provided on a base material by laminating a heat-melting layer on a substrate, wherein a second heat-melting layer is provided on at least a support side of the first heat-melting layer. When forming by a hot melt coating method using a heating medium roll, a coating side heating medium roll and a coating agent tank,
The temperature of the support-side heat medium roll is set to be equal to or lower than the melting point of the first heat-melting layer, and the temperature of the coating-side heat medium roll and the temperature of the coating agent tank are set to 0 to 30 ° C. higher than the melting point of the second heat-melting layer. A manufacturing method characterized by setting. 2. The method according to claim 1, wherein the temperature of the coating-side heating medium roll and the temperature of the coating agent tank are set in a temperature range 5 to 20 ° C. higher than the melting point of the second hot-melt layer. 3. The hot melt coating method is an offset coating method in which at least a backup roll is used as a support-side heating medium roll and at least a print roll and a pickup roll are used as a coating-side heating medium roll. 3. The production method according to 1 or 2. 4. The hot melt coating method is an offset gravure coating method in which at least a backup roll is used as a support-side heating medium roll and at least a print roll and a gravure roll are used as a coating-side heating medium roll. Item 3. The method according to Item 1 or 2. 5. The hot melt coating method is a direct gravure coating method using at least a backup roll as a support-side heating medium roll and at least a gravure roll as a coating-side heating medium roll. 3. The production method according to item 2. 6. The method according to claim 1, wherein the hot-melt coating method is a reverse coating method in which a coating-side heating medium roll in contact with the substrate is rotated in a direction opposite to a traveling direction of the substrate. The production method according to any one of the above.