JPH04305492A - Medium to be thermally transferred - Google Patents

Abstract

PURPOSE:To provide a medium to be thermally transferred which is excellent in chemical resistance such as alcohol resistance, oil resistance, plasticizer resistance, etc., resistance, and ink image acceptivity for thermal transfer ink. CONSTITUTION:A medium to be thermally transferred is obtained wherein an ink image acceptive layer containing at least one kind of polyester resin or epoxy resin and a lubricant is provided onto a base material.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a thermal transfer medium used in a thermal transfer method, and in particular, ticket paper such as train tickets, commuter passes, and pass tickets, cards such as prepaid cards, ID cards, safety cards, etc. The present invention also relates to a thermal transfer medium suitable for labels such as POS labels.

0002

2. Description of the Related Art With the rapid development of OA and FA, various terminal devices are required, and among them, there is a remarkable demand for recording devices such as facsimiles and printers that convert electrical signals into visible images. The thermal transfer recording method is widely used in these terminals because the device has advantages such as being simple, compact, noiseless, and maintenance-free. Recently, the demand for thermal transfer recording methods in combination with magnetic recording methods has been increasing for tickets such as train tickets, commuter passes, and passes, cards such as prepaid cards, ID cards, safety cards, and logistics and distribution. It has also come to be used for labels such as POS labels. In order to achieve reliability and security, these ticket papers, cards, and labels meet strict requirements, such as image receptivity that allows high-quality, high-resolution transferred images, water resistance, sweat resistance, It is necessary to satisfy chemical resistance such as oil resistance, alcohol resistance, acid resistance, alkali resistance, and plasticizer resistance. In addition, since tickets and cards that use magnetic recording methods are passed through a device with a built-in magnetic head that reads magnetically recorded information at high speed, it is also necessary to accurately read barcodes printed on labels. Abrasion resistance is also required due to its properties.

On the other hand, the conventional thermal transfer recording method mainly uses waxes such as paraffin wax and microcrystalline wax, higher fatty acids such as stearic acid, and higher alcohols such as stearyl alcohol on a support such as an extremely thin polyethylene terephthalate film. A heat-sensitive transfer ink layer made of a coloring material such as a dye or a pigment is provided, and a heat-resistant protective layer made of silicone resin, nitrocellulose, etc. is provided on the opposite side to prevent sticking with the heat-sensitive head. A thermal transfer medium (ink ribbon) is overlapped with a thermal transfer medium, and heating is performed from the heat-resistant protective layer surface by a thermal head according to the recorded information, thereby transferring the information image on the thermal transfer medium onto the thermal transfer medium to create a desired image. It was to form a In this case, the conventional thermal transfer medium has been paper or polyethylene terephthalate film or polyethylene laminate paper that does not have ink image receptivity, so when the thermal transfer ink is mainly composed of soft wax and is transferred to the thermal transfer medium, It has the disadvantage that chemical resistance and abrasion resistance cannot be satisfied, and the transferred image can easily be removed with a fingernail or the like. In order to improve this drawback, waxes with low penetration such as carnapa wax, polyethylene wax, and montan wax, or thermoplastic resins such as polyester resin, epoxy resin, ethylene-vinyl acetate copolymer resin, and polyamide resin are mainly used. A thermal transfer ink has been proposed. In particular, thermal transfer inks made mainly of thermoplastic resins are effective in chemical resistance and abrasion resistance, and have been rapidly developed in recent years.

However, despite these improvements in thermal transfer inks, the image receptivity and abrasion resistance (fixing properties) of thermal transfer inks are still poor on conventional thermal transfer media themselves.
Since there are problems with the above characteristics, it is not possible to satisfy the above-mentioned characteristics. On the other hand, the chemical resistance of the ink image receiving part of the thermal transfer medium using polyethylene terephthalate film as a support,
In order to satisfy wear resistance, various thermosetting resins such as polyester resins containing curing agents, polyurethane resins, various cellulose resins, silicone resins, ultraviolet curable resins, and electron beam curable resins are used. pigment, wax,
Proposals have been made to provide an ink image-receiving layer containing silicone oil or the like on the support, but although the resin group has excellent chemical resistance, abrasion resistance, and heat resistance, it is difficult to thermoplasticize. Image receptivity and abrasion resistance of thermal transfer ink (
There is a problem in that the required characteristics (fixability) cannot be satisfied. Further, wax contained in the ink image-receiving layer,
Silicone oil and the like do not effectively affect the image receptivity and abrasion resistance (fixing properties) of the thermal transfer ink, so
In the end, conventional thermal transfer media do not satisfy all of the image receptivity, chemical resistance, and abrasion resistance of thermal transfer inks at the same time.

[0005]

Problems to be Solved by the Invention The present invention improves the image receptivity for thermal transfer ribbon ink of the ink image receiving layer constituting the thermal transfer medium of ticket paper, cards, and labels used in thermal transfer methods, and also improves water resistance and sweat resistance. The purpose is to improve chemical resistance and wear resistance such as oil resistance, oil resistance, alcohol resistance, acid resistance, alkali resistance, and plasticizer resistance.

[0006]

[Means for Solving the Problems] As a result of intensive studies in order to solve the above problems, the present inventors have developed a thermal transfer medium having an ink image receiving layer for receiving thermal transfer ink on a support. The present invention has been completed by incorporating at least one of polyester resin or epoxy resin and a lubricant into the ink image-receiving layer.

Each layer of the thermal transfer medium of the present invention will be explained below. Supports used in the present invention include polyethylene terephthalate, polyimide, polycarbonate, cellophane, aromatic polyamide, polyolefin,
Examples include resin films such as vinyl chloride, high-quality paper, coated paper, art paper, woven fabric sheets, laminated paper, synthetic paper, metal plates, and glass.

The ink image-receiving layer of the present invention is formed by dispersing or dissolving a lubricant in at least one type of polyester resin or epoxy resin. The polyester resins used in the present invention include aliphatic polyester, polydimethylene malonate, polyethylene terephthalate, polytrimethylene terephthalate, polydiethylene glycol terephthalate, polyethylene isophthalate, polyethylene phthalate, polyethylene-1,5-naphthalate, polyethylene-1, 4-naphthalate, polyethylene-2,7-naphthalate, polyester (diethylene glycol-diphenylcarboxylic acid), polyester (
bis-P-carboxyphenoxybutane-ethylene glycol), etc., and can be used alone or in combination of two or more, and in particular, glass transition temperature (hereinafter referred to as
It is called Tg. ) is preferably 60°C or higher. That is, if the Tg is higher than 60°C,
The chemical resistance and abrasion resistance of the ink image-receiving layer can be further improved. In addition, the epoxy resins used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, phenol novolac type epoxy resin, and cresol novolac type epoxy resin. Epoxy resins, glycidyl ether type epoxy resins, etc. can be used alone or in combination of two or more, and it is particularly preferable to use those having a softening point of 100° C. or higher. That is, the softening point is 1
When the temperature is 00° C. or higher, more sufficient performance can be obtained in terms of chemical resistance, heat resistance, and abrasion resistance. In addition, Tg, softening point, and melting point of lubricant were all measured using the DSC method (heating rate 10
°C/min, analysis is shown as peak value. ) is required.

[0009] The lubricant to be added to the ink image-receiving layer is as follows:
carnauba wax, candelilla wax, polyethylene wax, polypropylene wax, ester wax, montan wax, montan wax derivative, oxidized microwax, Fischer-Trobsch wax,
Waxes such as hydrogenated castor oil, higher fatty acids such as palmitic acid, myristic acid, stearic acid, and oleic acid, fatty acid amides such as palmitic acid amide, stearic acid amide, and oleic acid amide, lauryl palmitate, stearyl stearate, and stearyl behenate. , esters of higher fatty acids such as behenyl behenate, stearyl alcohol,
Examples include higher alcohols such as behenyl alcohol, fatty acid metal salts such as zinc stearate, barium stearate, and calcium stearate, and fluorocarbon fine particles. Among these lubricants, polyethylene wax is particularly preferred in the present invention.

The amount of the lubricant to be blended is suitably in the range of 0.5 to 30 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the total solid content in the ink image-receiving layer. If the blending amount is less than 0.5 part by weight, the friction coefficient of the ink image-receiving layer tends to increase and the abrasion resistance tends to decrease. On the other hand, if the amount is more than 30 parts by weight, the image receptivity and fixing properties of the thermal transfer ink tend to deteriorate.

The surface of the ink image-receiving layer of the present invention is desired to have good smoothness in order to improve adhesion to the thermal transfer ink ribbon. That is, the Bekk smoothness (JIS8119-1976) of the ink image-receiving layer is preferably 300.
The time is preferably at least 500 seconds, more preferably at least 500 seconds. In order to achieve the smoothness of the ink image-receiving layer at such a value, it is necessary to use a support made of a highly smooth resin film as the support, or to provide an anchor coat layer on the support.
This can be achieved by performing surface treatment such as calendering after providing the ink image-receiving layer.

The ink image-receiving layer of the present invention is prepared by blending inorganic or organic pigments, antioxidants, colorants, antistatic agents, curing agents, etc. in addition to the above-mentioned resins and lubricants, as required, in a suitable solvent. Using a paint obtained by dissolving or dispersing in
．． The thickness is 0.1 to 20 μm, preferably 0.1 to 10 μm.

The structure (layer structure) of the thermal transfer medium of the present invention will be explained with reference to the drawings. FIG. 1 shows the basic structure of the thermal transfer medium of the present invention. Further, although FIGS. 2 to 4 are schematic cross-sectional views showing other embodiments of the thermal transfer medium of the present invention, the present invention is not limited to these configurations. Fig. 1 shows a thermal transfer medium in which an ink image receiving layer 2 is provided on a support 1, and Fig. 2 shows an ink image receiving layer 2 provided on a support 1, and an adhesive layer 3 and a release paper 4 on the opposite side. FIG. 3 shows a thermal transfer medium in which an ink image receiving layer 2 is provided on a support 1, and a magnetic recording layer 5 and a protective layer 6 are sequentially provided on the opposite surface. An ink image receiving layer 2 is provided on a support 1, and a magnetic recording layer 5, a hiding layer 7, and a magnetic recording layer 5 are provided on the opposite side.
This is a thermal transfer medium in which a printing layer 8 and a protective layer 6 are sequentially provided.

The magnetic recording layer 5 includes a binder such as polyester resin, vinyl chloride resin, polyurethane resin, vinyl chloride/vinyl acetate copolymer, etc., and ferromagnetic powder such as γ-Fe2O3, barium ferrite, etc., and optionally Pigments and the like are uniformly dispersed therein, and the layer is provided on the support opposite to the ink image-receiving layer to a thickness of 1 to 30 μm, preferably 3 to 15 μm, by solvent coating, gravure printing, or the like.

Furthermore, for the purpose of preventing counterfeiting, a plurality of high permeability magnetic recording layers such as sendust and permalloy, and magnetic recording layers with a low coercive force of about 200 to 1000 Oe such as iron oxide magnetic powder are laminated by the above method. You can also. If necessary, a printing layer 8 for company names, cautionary notes, commercials, various marks, patterns, etc. may be printed on the magnetic recording layer.
can be provided, for example, by printing such as gravure printing or flexographic printing. In order to obtain a good printing layer, it is better to provide a hiding layer 7 between the magnetic recording layer and the printing layer in order to hide the coloring of the magnetic recording layer. The concealing layer can be provided by coating or printing a paint in which a pigment such as aluminum paste or titanium oxide is uniformly dispersed in a resin such as a polyester resin or a polyurethane resin.

Furthermore, a protective layer 6 can be provided on the magnetic recording layer (on the printing layer if a printing layer is provided) for the purpose of protecting the surface of the magnetic recording layer. Examples of binders for the protective layer include polyester resins, polyurethane resins, polystyrene resins, various cellulose resins, polyimide resins, silicone resins, fluororesins, polyarylate resins, polycarbonate resins, phenolic resins, epoxy resins, alkyd resins, and melamine. Examples include various thermoplastic resins and thermosetting resins such as resins and copolymers between these resins. The protective layer can be prepared by adding wax, silicone, pigment, etc. to the binder as necessary, or by kneading the binder.
Solvent coating with ink or paint obtained by dissolving or dispersing in a suitable solvent,
By gravure printing, flexographic printing, screen printing, offset printing, etc., a layer of 0.01 to 10 μm, preferably 0.0 μm, is coated on the magnetic recording layer (on the print layer if a print layer is provided).
It is provided to have a thickness of 1 to 5 μm.

[0017] Depending on the use of the thermal transfer medium of the present invention,
Printing can also be performed on the surface of the ink image-receiving layer and/or under the ink image-receiving layer (between the support and the image-receiving layer) to the extent that the image-receiving properties and fixing properties of the thermal transfer ink are not impaired. That is,
For example, printing of patterns, marks, characters, etc. that do not have solid areas to prevent tampering on ticket paper and cards, printing of frames and characters in addition to transferred images on labels, etc., and printing of frames and characters in advance on ID cards and advertising media. Cards such as prepaid cards that also serve as cards can be printed in color or with text in advance.

[0018]

[Formation of ink image receiving layer]

Glass beads were added to the above mixed solution and dispersed for 2 hours using an attritor, followed by a polypropylene synthetic resin with a thickness of 250 μm (manufactured by Oji Yuka Synthetic Paper Co., Ltd.: Yupo base paper FP250).
An ink image-receiving layer was provided on a support consisting of the following by a solvent coating method so that the coating thickness after drying was 2.0 μm, thereby obtaining a thermal transfer medium of the present invention.

Example 2 [Formation of magnetic recording layer] After dispersing the above mixed solution in a ball mill for 8 hours, the above curing agent was added, and after further dispersing for 1 hour, a solvent coating was applied onto a milky white polyethylene terephthalate film with a thickness of 188 μm. While the paint was still wet, it was subjected to orientation treatment using a magnetic field orientation treatment device, and dried at 100° C. for 5 minutes to form a magnetic recording layer with a thickness of 15 μm. [Formation of protective layer] The above mixed solution was stirred with a disper to dissolve the binder, and then coated on the above magnetic recording layer by a solvent coating method so that the coating thickness after drying was 3.0 μm to protect it. formed a layer. [Formation of ink image-receiving layer] Glass beads were added to the above mixed solution and dispersed for 2 hours using an attritor to prepare a paint for the ink image-receiving layer, and after drying, it was applied to the opposite side of the above protective layer by a solvent coating method. An ink image-receiving layer was provided by coating to a thickness of 2.0 μm to obtain a thermal transfer medium of the present invention.

Example 3 A thermal transfer medium of the present invention was obtained in the same manner as in Example 2, except that the formulation of the ink image-receiving layer was changed as follows.

Comparative Example 1 A comparative thermal transfer medium was obtained in the same manner as in Example 2, except that the formulation of the ink image-receiving layer was changed as follows.

Comparative Example 2 A comparative thermal transfer medium was obtained in the same manner as in Example 2, except that the formulation of the ink image-receiving layer was changed as follows.

Next, the manufacturing method of the thermal transfer ink ribbon used in the evaluation of the thermal transfer media of Examples and Comparative Examples will be described below. It is not limited to this. A heat-resistant layer made of silicone resin and having a thickness of 0.5 μm was provided on a polyethylene terephthalate film having a thickness of 4.5 μm. Next, a paint obtained by dispersing the following mixed solution for 2 hours using an attritor was applied to the surface opposite to the heat-resistant layer by a solvent coating method so that the coating thickness after drying was 3 μm. Obtained an ink ribbon.

Using the above thermal transfer ink ribbon, the surface smoothness, sweat resistance, oil resistance, alcohol resistance, acid resistance, alkali resistance, and plasticizer resistance of the thermal transfer medium of each example and comparative example were evaluated. Table 1 summarizes the results of evaluating various properties such as chemical resistance, abrasion resistance, and transferability. Moreover, the measurement method and evaluation method of each characteristic are shown below. The "ink image receptivity" for thermal transfer inks is shown in Table 1 as a result of comprehensive evaluation of various properties. (a) Surface smoothness Beck smoothness (JIS.8119-1976) (b)
High-density transfer thermal printer (printer equipped with an 8 dot/mm thermal head: Printing energy: 0.
65 mJ/dot, pulse width: 1.5 ms) and the above-mentioned ink ribbon, the transfer was performed and the image density unevenness, uniformity, sharpness, and presence or absence of random bridges and voids were evaluated. All evaluations are visual evaluations using enlarged photographs, etc. ○: Satisfies all evaluation items. △: There is only one defect in the evaluation item. ×: Two or more defects in evaluation items. (c) Alcohol resistance The thermal transfer medium that was transferred using the printer of (b) was immersed in ethanol for 2 minutes, and changes in the transfer surface were examined. ○: Peeling, scratches, fading, and decolorization of the transferred image area, and peeling and scratches of the ink image-receiving layer are hardly observed. Δ: Slight peeling, scratches, fading, or decolorization of the transferred image area and/or peeling or scratches of the ink image-receiving layer. ×: Peeling, scratches, discoloration, or decolorization of the transferred image area and/or peeling or scratches of the ink image-receiving layer are observed considerably. (d) Acid resistance: Use a 5% acetic acid aqueous solution with a pH of 3. The evaluation method is based on (c). (e) Alkali resistance pH 12, using a 1N sodium hydroxide aqueous solution. The evaluation method is based on (c). (f) Oil resistance After transfer was performed using the printer of (b), several drops of edible soybean oil were dropped on the transfer surface, and after 24 hours, the oil was wiped off with gauze to examine changes in the transfer surface. The evaluation method is based on (c). (g) Plasticizer resistance After transfer is performed using a printer (b), press a plasticizer-containing plastic eraser onto the transfer surface with a pressure of 2 kg/cm2, leave it for 24 hours, then remove the plastic eraser and transfer. We investigated changes in the surface. ○: No change at all. △: Slight transfer, peeling, staining, etc. on the transfer surface to the eraser (transfer image area, ink layer if a print layer is set on the ink image-receiving layer, ink image-receiving layer). ×: Significant transfer, peeling, staining, etc. on the transfer surface to the eraser (transfer image area, ink layer if a print layer is set on the ink image-receiving layer, ink image-receiving layer). (h) Abrasion resistance After transferring with the printer of (b), using a paperboard abrasion tester (manufactured by Kumagai Riki Kogyo Co., Ltd.), a polishing sheet (manufactured by Sankyo Rikagaku Co., Ltd., trade name: Wrapping sheet WA#8000) was used. ) at room temperature: 20℃, load: 500
g/cm, number of frictions: 1,000 reciprocating conditions. ○: Hardly any scratches, peeling, or stains are observed on the transfer surface (transfer image area, ink image-receiving layer, if a printing layer is set on the ink image-receiving layer). △: One of scratches, peeling, and stains is slightly observed on the transfer surface (transfer image area, printing layer and ink image-receiving layer if a printing layer is set on the ink image-receiving layer). ×: At least two of scratches, peeling, and stains are observed on the transfer surface (transfer image area, printing layer and ink image-receiving layer if the printing layer is set on the ink image-receiving layer), or one or more of the following is observed. Even if there is, the extent is large. (i) Sweat resistance After being immersed for one week in artificial sweat fluids (acidic and alkaline) specified in JIS L 0848-1978, the test (h) is conducted.

As is clear from Table 1, the thermal transfer medium of the present invention is sweat resistant because the ink image receiving layer that receives the thermal transfer ink contains at least one type of polyester resin or epoxy resin and a lubricant. It satisfies various properties such as chemical resistance, oil resistance, alcohol resistance, acid resistance, alkali resistance, plasticizer resistance, etc., and abrasion resistance, and also provides excellent thermal transfer energy sensitivity and transfer quality. Ta.

Effects of the Invention The thermal transfer medium of the present invention has chemical resistance such as sweat resistance, oil resistance, and plasticizer resistance, and abrasion resistance, and has excellent ink image receptivity. It can be suitably used for ticket papers such as tickets and passes, cards such as prepaid cards, ID cards, and safety cards, and labels such as POS labels.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a configuration example of a thermal transfer medium of the present invention.

FIG. 2 is a sectional view showing a configuration example of a thermal transfer medium of the present invention.

FIG. 3 is a sectional view showing an example of the configuration of a thermal transfer medium of the present invention.

FIG. 4 is a sectional view showing an example of the structure of the thermal transfer medium of the present invention.

[Explanation of symbols]

1 Support 2 Ink image receiving layer 3 Adhesive layer 4 Release paper 5 Magnetic recording layer 6 Protective layer 7 Hidden layer 8 Printing layer

[Table 1]

Claims (4)

[Claims] 1. A thermal transfer medium comprising an ink image-receiving layer for receiving a thermal transfer ink on a support, characterized in that the ink image-receiving layer contains at least one of a polyester resin or an epoxy resin and a lubricant. Thermal transfer medium. 2. The thermal transfer medium according to claim 1, wherein the polyester resin has a glass transition temperature of 60° C. or higher. [Claim 3] The softening point of the epoxy resin is 100°C.
The thermal transfer medium according to claim 1, wherein the thermal transfer medium is as follows. 4. The thermal transfer medium according to claim 1, wherein the lubricant is polyethylene wax having a melting point of 80° C. or higher.