JPH08132740A - Heat-resistant and solvent-resistant thermal transfer recording material - Google Patents

Abstract

PURPOSE: To provide a thermal transfer recording material capable of forming a printing image having good transfer properties and heat resistance and good in solvent resistance and scratch resistance. CONSTITUTION: In a thermal transfer recording material wherein a hot-melt ink layer consisting of a vehicle and a pigment is provided on a base material, 85wt.% or more of the vehicle is a terpolymer resin consisting of methyl methacrylate, glycidyl dimethacrylate and butyl acrylate and the methyl methacrylate component in the terpolymer resin is 30-70wt.% and the glycidyl dimethacrylate component therein is 20-50wt.% and the butyl acrylate component therein is 5-20wt.%.

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 material having good transfer sensitivity and capable of forming an image having good heat resistance, solvent resistance and scratch resistance.

[0002]

2. Description of the Related Art Conventional thermal transfer recording materials are generally applied to a base material coated with a hot-melt ink containing a wax as a main component of a vehicle or a paper having a poor surface smoothness. In order to form an image of good quality or to form an image of good fastness, a heat-meltable ink containing a resin as a main component of a vehicle is applied.

In recent years, a thermal transfer recording material is used for printing a bar code or the like which is used for parts management in a manufacturing process in a manufacturing factory, product management, product management in the distribution field, article management in the field of use, and the like. Bar code printers and label printers are being used.

Some of the articles to which such a bar code is attached are exposed to a high temperature after the bar code is attached. For example, in the manufacturing process of printed wiring boards, 180 ℃
In the semiconductor inspection process, heat treatment at about 250 ° C. is performed.

Further, in the case of bar codes used for product management in manufacturing factories, etc., there are many opportunities to come into contact with solvents, oils, etc., so good solvent resistance is required, and bar codes used in the distribution field etc. In this case, since there are many occasions of being subjected to a rubbing action, good scratch resistance is required.

Not only bar codes but also outdoor commercials, election posters, general posters, standing signs, stickers, catalogs, pamphlets, calendars, etc. in the field of commercial printing, light packaging bags, foods, beverages, paints, etc. in the field of packaging. In the field of clothing, such as container labels and binding tapes, thermal transfer printers have come to be used for quality indication labels, process control labels, product control labels, and other high-mix low-volume production products. , Heat resistance is required.

However, none of the conventional thermal transfer recording materials can form an image having excellent transferability and satisfying all of heat resistance, solvent resistance and scratch resistance.

The conventional thermal transfer recording material mainly composed of wax has good transferability, but when exposed to a high temperature of about 250 ° C., it may be decomposed and the printed image may be broken to make it unreadable. Also, solvent resistance and scratch resistance are insufficient. In addition, a resin-based vehicle is relatively excellent in heat resistance, solvent resistance, and scratch resistance,
Transferability is inferior to wax-based ones.

A thermal transfer recording material satisfying all of transferability, heat resistance, chemical resistance and scratch resistance is disclosed in Japanese Patent Application Laid-Open No. 2-993.
91 and Japanese Patent Application Laid-Open No. 2-99392. However, JP-A 2-9
The thermal transfer recording material described in Japanese Patent No. 9391 has a surface of a thermoplastic resin layer containing a thermoplastic resin as a main component and a surface of a curing agent layer containing a curing agent for curing the thermoplastic resin, They are arranged alternately in the longitudinal direction of the substrate. To obtain a sufficiently cured image using this thermal transfer recording material, first transfer the thermoplastic resin layer, and then at the same location with a curing agent. The layers need to be transferred (transfer order can be reversed). Therefore, the printing process becomes complicated. The thermal transfer recording material described in JP-A-2-99392 is a laminate of a thermoplastic resin layer and a curing agent layer containing a curing agent for curing the thermoplastic resin. This thermal transfer recording material has a high possibility that the thermoplastic resin is cured by the curing agent on the substrate before the transfer.
There is a problem in terms of storability.

In view of the above points, an object of the present invention is that the transferability is good, the heat resistance is high enough to withstand a high temperature of about 150 to 280 ° C., and the solvent resistance and the scratch resistance are good. It is to provide a thermal transfer recording material capable of forming an image.

[0011]

The present invention provides a thermal transfer recording material comprising a substrate and a heat-meltable ink layer comprising a vehicle and a pigment, wherein 85% by weight or more of the vehicle is methyl methacrylate (hereinafter , MMA) and glycidyl methacrylate (hereinafter referred to as GMA).
Sometimes abbreviated) and butyl acrylate (hereinafter,
(May be abbreviated as BA)), and the MMA component in the terpolymer resin is 35 to 35%.
70% by weight, GMA component is 20 to 50% by weight, and BA component is 5 to 20% by weight, to a heat-resistant solvent-resistant thermal transfer recording material (first invention).

The present invention is also the same as the first invention,
The present invention relates to a heat-resistant, solvent-resistant thermal transfer recording material (second invention), characterized in that a thermal transfer control layer is provided between the substrate and the heat-meltable ink layer.

[0013]

ACTION AND EXAMPLE According to the first invention, 85% by weight or more of the vehicle is a terpolymer resin containing MMA, GMA and BA, and MMA in the terpolymer resin is
Ingredient is 35 to 70% by weight, GMA ingredient is 20 to 5
A heat transfer recording material having a good transfer sensitivity and capable of forming an image having good heat resistance, solvent resistance and scratch resistance can be obtained because the content of the BA component is 0 to 20% by weight. be able to.

Here, the terpolymer composed of MMA, GMA and BA can be represented by the following formula.

[0015]

Embedded image

(Where l is in the range of 7 to 210,
m is in the range 3-116 and n is in the range 1-47. Further, the terpolymer may be a block copolymer, a random copolymer, a graft copolymer, or an alternating copolymer. In addition, all the molecules of the terpolymer may be the above-mentioned l,
It is not necessary to satisfy the range of m and n, and it is sufficient that the range of l, m and n is satisfied as the average of all molecules. According to the second invention, since the thermal transfer control layer is provided between the base material and the heat-meltable ink layer, the adhesion between the base material and the heat-meltable ink layer is improved and the ink layer Problems such as falling out can be prevented.

Next, the thermal transfer recording material of the present invention will be described in detail.

In the thermal transfer recording material of the present invention, 85% by weight or more, preferably 90% by weight or more of the vehicle is M on the substrate.
A heat-meltable ink layer, which is the terpolymer resin composed of MA, GMA, and BA, is provided. If the content of the terpolymer resin in the vehicle is less than the above range, the heat resistance, solvent resistance and scratch resistance of the thermal transfer recording material may not be sufficiently exhibited.

In the present invention, the MMA component in the terpolymer is in the range of 35 to 70% by weight and G
The MA component is in the range of 20 to 50% by weight, and the BA component is in the range of 5 to 20% by weight. If the component fraction of the MMA component in the terpolymer is less than the above range, the solvent resistance such as toluene resistance and carbon tetrachloride resistance tends to decrease, while if it is more than the above range, Transferability tends to deteriorate. When the component fraction of the GMA component in the terpolymer is less than the above range, solvent resistance such as kerosene resistance and gasoline resistance tends to decrease, while when it exceeds the above range, scratch resistance is high. It tends to be bad. When the component fraction of the BA component in the terpolymer is less than the above range, solvent resistance such as gasoline resistance and ethanol resistance tends to decrease, while when it is more than the above range, it may be long-term. When preserved, blocking resistance tends to deteriorate. The average molecular weight of the terpolymer is preferably in the range of 2,000 to 30,000, and 2,000 to 20,000.
It is even more preferable that it is within the range. If the average molecular weight is less than the above range, the heat resistance, solvent resistance and scratch resistance will tend to deteriorate, while if it is more than the above range, the transferability will tend to deteriorate.

A heat-melting resin other than the terpolymer resin composed of MMA, GMA and BA may be blended with the vehicle within a range not impairing the object of the present invention. Examples of such heat-fusible resins include ethylene-vinyl acetate copolymer resins, ethylene-alkyl (meth) acrylate copolymer resins, phenol resins, styrene-acryl copolymer resins (the above-mentioned styrene / acryl copolymer resins). Those not included in the coalescence), polyester resin, polyamide resin and the like. The other heat-meltable resin is preferably used in an amount of 15% by weight or less, especially 5% by weight or less of the total amount of the vehicle.

The vehicle has a glass transition temperature of 40 to 80 from the viewpoint of storage stability and transferability of the thermal transfer recording material.
It is preferably in the range of 50 ° C, and more preferably in the range of 50 to 60 ° C.

From the standpoint of transferability, the content of the vehicle in the heat-meltable ink is preferably in the range of 40 to 95% by weight, and more preferably in the range of 60 to 80% by weight. More preferable.

Examples of the pigment that can be used in the present invention include various organic and inorganic pigments such as carbon black. The content of the pigment in the ink layer is preferably in the range of 5 to 60% by weight from the viewpoint of transferability and the like,
More preferably, it is in the range of 20-40% by weight.

In the heat-fusible ink layer in the present invention, in addition to the above-mentioned components, within the range that does not impair the object of the present invention,
You may mix | blend a dispersing agent etc. suitably.

The hot-melt ink layer in the present invention is prepared by dissolving the vehicle component in a solvent and further dissolving and dispersing pigments and other additives to prepare a coating liquid, and applying the coating liquid on a substrate. (The thermal transfer control layer is provided on the thermal transfer control layer in a preferred embodiment in which the thermal transfer control layer is provided between the base material and the heat-meltable ink layer), and then dried.

The coating amount of the hot-melt ink layer in the present invention (the coating amount after drying, the same applies hereinafter) is usually 0.02 to 5 g /
m ² and more preferably 0.5 to 3 g / m ² .

Examples of the substrate include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film and polyarylate film, polycarbonate film, polyamide film, aramid film, polyether sulfone film, polysulfone film, polyphenylene sulfide. A film, a polyetheretherketone film, a polyetherimide film, a modified polyphenylene ether film, a polyacetal film, and other various plastic films generally used as a substrate film for an ink ribbon of this type can be used. High density thin paper such as condenser paper can also be used. Substrate thickness is usually 1
It is about 10 to 10 μm, and the range of 1 to 6 μm is preferable from the viewpoint that the thermal diffusion can be reduced and the resolution can be improved.

In the present invention, a thermal transfer control layer is preferably provided between the substrate and the heat-meltable ink layer in order to improve the adhesion between the substrate and the heat-meltable ink layer. The thermal transfer control layer contains a heat-melting resin as a main component, and examples of the heat-melting resin include ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate resin, polyurethane resin, polybutene, and polybutadiene.
Further, when the substrate is a polyethylene terephthalate film, the thermal transfer control layer is particularly preferable because the adhesion between the substrate and the hot-melt ink layer is not good. In this case, as the heat-melting resin of the thermal transfer control layer, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate resin or polyurethane resin is particularly preferable.

In the thermal transfer control layer, a plasticizer, a pigment and the like may be blended in addition to the above-mentioned heat-meltable resin within the range that does not impair the object of the present invention. Examples of the plasticizer include DOP and D
Examples include EP and DOZ. Examples of the pigment include carbon black, titanium oxide, calcium carbonate and the like.

The thermal transfer control layer has a softening point in the range of 60 to 120 ° C. from the viewpoint that the substrate and the heat-fusible ink layer are brought into close contact with each other and easily peeled off during transfer. Is preferable, and it is more preferable that it is in the range of 60 to 100 ° C.

The thermal transfer control layer in the present invention can be formed by dissolving the heat-meltable resin in a solvent to prepare a coating solution, coating the coating solution on a substrate, and drying.

The coating amount of the thermal transfer control layer in the present invention is
It is usually 0.02 to 1 g / m ² , and more preferably 0.
It is 1 to 0.3 g / m ² .

When the thermal transfer recording material of the present invention is used in a thermal transfer printer equipped with a thermal head, a silicone resin, a fluororesin, a nitrocellulose resin, or the like is formed on the back surface of the base material (the surface which is in sliding contact with the thermal head). It is possible to provide a conventionally known stick-preventing layer made of various heat-resistant resins modified by, for example, silicone-modified urethane resin, silicone-modified acrylic resin, or a mixture of these heat-resistant resins with a lubricant. preferable.

To form a printed image using the thermal transfer recording material of the present invention, the ink layer of the thermal transfer recording material is superposed on the transfer target, and imagewise thermal energy is applied to the ink layer. A thermal head is generally used as a heat source for giving heat energy, but any known one such as a laser beam, an infrared flash, or a heat pen can be used.

In the case where the transfer target has a three-dimensional shape that is not a sheet, and the surface thereof is a curved surface, thermal transfer by laser light is advantageous because heat energy can be easily applied.

Since the thermal transfer recording material of the present invention can form an image having excellent heat resistance as described above, it is suitable for forming an image on a transfer object which is subjected to heat treatment at a temperature of 150 ° C. or higher. used. If the temperature of the heat treatment to which the transferred material is subjected is too high, the vehicle component tends to decompose and the form as the printed image tends to disappear, so the temperature of the heat treatment to which the transferred material is subjected is about 280 ° C. or less. Is preferred.

When a printed image is formed using the thermal transfer recording material of the present invention, the printed image may be directly formed on the target transferred material, but it may be printed on the sheet-shaped transferred material (image receiving material) in advance. After forming an image, the image receptor may be attached to a target transfer target by an appropriate means such as a heat resistant adhesive.

As the sheet-shaped image receptor, various heat-resistant sheet materials can be used, but those disclosed in Japanese Patent Application No. 6-141996 previously filed by the present applicant are preferably used. . This is an image receptor in which a white pigment and an image receiving layer containing an organic binder as essential components are provided on one side of the substrate, and a heat resistant adhesive layer is provided on the other side,
The organic binder is a phenoxy resin or a phenoxy resin and a saturated polyester resin.
In addition, sheet-shaped materials of heat-resistant resin such as polyimide, cloth-shaped materials of glass fiber or ceramic fiber, those coated or impregnated with heat-resistant resin, sheet-shaped materials of glass or ceramics, sheet-shaped materials of metal, etc. Can be given.

Since the thermal transfer recording material of the present invention can give an image having excellent heat resistance and solvent resistance, the material to be transferred has a temperature of 150 to 280 ° C. in a manufacturing process such as a printed wiring board and a semiconductor inspection process. It is preferably used for forming an image on an object which is subjected to a heat treatment at a high temperature of the order.

Next, the present invention will be described with reference to examples.

Examples 1 to 5 and Comparative Examples 1 to 3 A coating amount of 0.25 g / a silicone resin on one surface of a polyethylene terephthalate film having a thickness of 5 μm
An m ² stick preventing layer was formed, and an ink coating solution having the following formulation was applied to the surface on the opposite side and dried to form a transfer control layer having a coating amount of 0.20 g / m ² .

Treatment Weight% Ethylene-vinyl acetate copolymer resin 5 (Copolymerization ratio 59/41, softening point 98 ° C.) Toluene 95 The ink coating liquid having the formulation shown in Table 1 is applied onto the transfer control layer. Then, it was dried to form a heat-meltable ink layer having a coating amount of 2 g / m ² to obtain a heat transfer recording material. Table 1 shows the glass transition temperature of the vehicle of the heat-meltable ink.

[0043]

[Table 1]

The heat resistance of each ink was evaluated.
Further, printing was performed using each of the thermal transfer recording materials, and the obtained printed images were evaluated for solvent resistance, scratch resistance and transferability. The printing was performed using a thermal transfer bar code printer (B-30 manufactured by Tokyo Electric Co., Ltd.) under the following conditions.

Applied energy: 25.8 mJ / mm ² Printing speed: 2 inches / second Platen pressure: Strong Printing pattern: Checker flag pattern [Heat resistance] Each ink after drying was weighed by an electronic balance of about 10 mg and placed in a heat oven. After heat treatment at 250 ° C. for 1 hour, the weight was measured, the ink residual ratio (%) represented by the following formula was determined, and the heat resistance was evaluated. If the residual ratio is 80% or more, there is no practical problem.

Ink residue rate (%) = (weight after heat treatment / weight before heat treatment) × 100 [Solvent resistance] As an image receptor, an adhesive layer was formed on the aluminum vapor deposition side of an aluminum vapor deposition polyethylene terephthalate film. The printed image (checkered flag pattern) formed on the surface of the aluminum-deposited polyethylene terephthalate film was rubbed with a cotton swab impregnated with each solvent shown in Table 2 10 times, and evaluated according to the following criteria. Evaluation Criteria A: No printed image can be obtained. B: The image is very slight. C ... A few impressions can be taken. D: I can get a lot of impression. Evaluations A and B are within the practical range.

[Scratch resistance] An image (checkered flag pattern) obtained by the same method on the same image receptor as in the solvent resistance test was subjected to the following scratch resistance test and evaluated according to the following criteria. Test conditions Test machine: Love tester manufactured by Yasuda Seiki Seisakusho Ltd. Friction material: Sand eraser Number of reciprocations: 10 times Evaluation standard A: No change in printed image. B: Almost no change in the image. C: I can get a lot of impression. D: The image is removed and disappears. Evaluations A and B are within the practical range.

[Transfer Sensitivity] As an image receptor, a thickness of 76 μm
A silicone resin-based pressure-sensitive adhesive layer was formed on one side of the above polyimide film, and a white coating layer (coating amount 28 g / m ² ) of the following composition was formed on the opposite side thereof.

Component parts by weight Saturated polyester resin 5 Phenoxy resin 11 Titanium oxide 29 The reflection optical density (OD value) of the solid print portion of the printed image (checkered flag pattern) obtained on the white coating layer of the image receptor is reflected density Measuring device (Macbeth RD914)
And the transfer sensitivity was evaluated. If the OD value is 0.8 or more, there is no practical problem.

[0050]

[Table 2]

[0051]

The thermal transfer recording material of the present invention has a good transfer sensitivity and gives a clear printed image, and the obtained printed image is excellent in heat resistance, solvent resistance and scratch resistance.
Also, the adhesion between the base material and the heat-meltable ink layer is good, and problems such as the ink layer falling off can be prevented.

Therefore, at a manufacturing plant or the like, 150 to 28
It can be advantageously used as a thermal transfer recording material for forming an image such as a barcode on an article exposed to a high temperature of about 0 ° C.

Claims (2)

[Claims] 1. A thermal transfer recording material comprising a substrate and a heat-meltable ink layer comprising a vehicle and a pigment, wherein at least 85% by weight of the vehicle comprises methyl methacrylate, glycidyl methacrylate and butyl acrylate. It is a terpolymer resin, the methyl methacrylate component in the terpolymer resin is 35 to 70% by weight, and the glycidyl methacrylate component is 20 to 50% by weight.
And a butyl acrylate component in an amount of 5 to 20% by weight. 2. The heat-resistant solvent-resistant thermal transfer recording material according to claim 1, wherein a thermal transfer control layer is provided between the base material and the heat-meltable ink layer.