JP2000085251A - Thermal transfer ink sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal transfer ink sheet having excellent safety regarding an environmental problem or the like by holding a heat resistant ink containing no lead and no bismuth or transparent glass powder and organic binder as at least components at a support base material. SOLUTION: The thermal transfer ink sheet adapted to formation or the like of a baking label is formed by holding a heat resistant ink containing no lead and no bismuth and containing colored or transparent glass powder and an organic binder as at least components at a support base material. The powder to be used is retained as ink information by fusion bonding in the case of baking a baking sheet and bonding to a baked material of the baking sheet, and fixed to the baking material. The colored or transparent powder containing no toxic component such as the lead and the bismuth is used. The powder to be used preferably contains a phosphoric acid, zinc and alumina as components from points of safety by avoiding its toxicity and low temperature fixability or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer ink sheet suitable for forming a fired label.

[0002]

BACKGROUND OF THE INVENTION Information comprising heat-resistant ink is provided by a thermal transfer method to a baking sheet obtained by preserving a powder made of glass or other ceramics through an organic binder,
While it is temporarily attached to an adherend such as a cathode ray tube via an adhesive layer and the like and subjected to heat treatment, while baking the baking sheet under the preservation of ink information and the disappearance of organic components, forming a baking label, A method of fixing it to an adherend is known (Japanese Patent Publication No. 7-45258). This method aims at coping with a multi-product small-lot production system by forming an identification label or the like excellent in weather resistance, heat resistance, chemical resistance and the like on the spot or the like.

Heretofore, as a thermal transfer ink sheet used in the thermal transfer system, there has been known a thermal transfer ink sheet using lead glass or bismuth glass so that good fixability can be obtained even at low temperature firing. However, lead and bismuth are highly toxic, and it is desired not to use them from the viewpoint of environmental problems. Therefore, it is required to provide an alternative thermal transfer ink sheet having excellent safety.

[0004]

The present invention relates to a thermal transfer ink sheet which can provide ink information by a thermal transfer method, can form a fired pattern having excellent low-temperature fixability, excellent heat resistance and durability, and has excellent safety. The task is to develop

[0005]

According to the present invention, there is provided a thermal transfer ink sheet comprising a support substrate holding a heat-resistant ink containing at least a colored or transparent glass powder containing no lead and bismuth and an organic binder. Is provided.

[0006]

According to the present invention, a thermal transfer ink sheet excellent in safety can be obtained without restriction of a manufacturing apparatus, and ink information such as a pattern is printed on a baking sheet via a thermal transfer printer or the like using the thermal transfer ink sheet. In addition, it is possible to obtain a fired label which is excellent in heat resistance, weather resistance, chemical resistance and the like in which the ink information applied during firing of the firing sheet is well preserved. Also, a thermal transfer ink sheet having excellent low-temperature fixability can be obtained by using glass powder containing phosphoric acid, zinc and alumina as components.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The thermal transfer ink sheet of the present invention comprises a support substrate containing a colored or transparent glass powder containing no lead and bismuth and a heat resistant ink containing at least an organic binder.

The heat-resistant ink is prepared so as to be integrated with a fired body of a firing sheet through a firing process.
Colored or transparent one or two that does not contain lead and bismuth
It is prepared using at least one kind of glass powder and one or more kinds of organic binders.

The preparation of the heat-resistant ink can be carried out, for example, by a method in which the components are mixed by a ball mill or the like using a solvent as necessary to obtain a paste-like fluid. In the preparation thereof, one or more other ceramic powders and appropriate additives such as a heat-resistant colorant, a plasticizer and a dispersant may be added as necessary.

[0010] The composition of the heat-resistant ink may be appropriately determined depending on the contrast with the fired body of the firing sheet and the fixability. In general, components such as glass powder and other ceramic powder and heat-resistant colorant as needed, which remain when firing the firing sheet and form ink information, and dry components such as solvents evaporate 99 based on dry solidification
% By weight, especially 5 to 95% by weight, especially 10 to 90% by weight.

The glass powder used for preparing the heat-resistant ink melts and binds when the firing sheet is fired and remains as ink information, and also binds to the firing body of the firing sheet and is fixed on the firing body. Is what you do. When the heat-resistant ink contains a heat-resistant colorant or the like, the ink is fused to form ink information.

In the present invention, a colored or transparent glass powder containing no toxic components of lead and bismuth is used as the glass powder. Glass powder that can be preferably used from the viewpoint of fixing properties by low-temperature firing has a softening point of 600 ° C. or less,
Among them, those having a temperature of 500 ° C. or less, especially 450 ° C. or less.

A glass powder which can be particularly preferably used from the viewpoints of safety due to avoidance of toxicity and low-temperature fixability is one containing phosphoric acid, zinc and alumina as components. The composition can be appropriately determined depending on the eutectic point and the like.
The glass powder used should be as fine as possible in the form of a frit in terms of low-temperature fixability and the ability to form fine and clear ink information, and should have an average particle diameter of 10 μm or less, especially 1 μm or less. Is preferred. The colored glass may be a colored glass containing a pigment or the like.

As the other ceramic powder and heat-resistant colorant used as needed in the preparation of the heat-resistant ink, appropriate ones can be used. Incidentally, as examples, silica and zirconia, titania and alumina, zinc oxide and calcium oxide, manganese oxide and alumina, chromium oxide and tin oxide,
Iron oxide, red matter such as cadmium sulfide / selenium sulfide, blue matter such as cobalt oxide, zirconia / vanadium oxide, chromium oxide / divanadium pentoxide, chromium oxide / cobalt oxide / iron oxide / manganese oxide / chromate, Black matter such as manganate or carbon powder, zirconium
Yellow substances such as silicon / praseodymium, vanadium / tin, chromium / titanium / antimony, green substances such as chromium oxide, cobalt / chromium, alumina / chromium, aluminum /
Examples include manganese and pink-colored substances such as iron, silicon, and zirconium.

The ceramic powder and heat-resistant colorant that can be preferably used do not contain toxic components such as lead and bismuth. Further, from the viewpoint of heat resistance and the like, it is an inorganic colorant such as a metal oxide pigment. The amount of the ceramic powder and the heat-resistant colorant can be determined as appropriate depending on the coloring concentration of the ink.
0000 parts by weight or less, especially 10 to 5000 parts by weight, especially 30 to 1000 parts by weight.

The organic binder used in the preparation of the heat-resistant ink adheres to the supporting substrate while holding the glass powder and the like, thereby enabling the formation of a thermal transfer ink sheet, and the thermal transfer ink of the ink sheet is thermally transferred. It is an object of the present invention to make it possible to transfer and adhere to a firing sheet by a method.

As the above-mentioned organic binder, an appropriate material such as a resin or wax which disappears due to thermal decomposition or the like at the time of baking of the baking sheet is used. Those excellent in thermal transferability and the like are preferably used. Incidentally, examples include hydrocarbon resins, vinyl or styrene resins, acetal resins and butyral resins, acrylic resins and polyester resins, urethane resins and cellulose resins, cellulose resins, paraffin waxes. And natural waxes, ester waxes, higher alcohol waxes, higher amide waxes and the like.

If the organic binder in the heat-resistant ink is significantly different from the organic binder in the firing sheet for imparting ink information in properties such as the thermal decomposition temperature, the fired body may have poor appearance such as foaming or deformation. It is preferable that these organic binders are made of the same kind because of easiness and the like.

The amount of the organic binder used in the heat-resistant ink is 1% by weight or more, preferably 5 to 95% by weight, particularly 1% based on the dry and solidified state of the heat-resistant ink.
The amount is suitably from 0 to 90% by weight, and practically preferably from 5 to 80% by weight of the components forming the ink information after firing.

As the solvent used as needed in preparing the heat-resistant ink, any suitable solvent can be used. In general, butyl carbitol, ethyl acetate, butyl cellosolve acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene and the like are used.

The thermal transfer ink sheet is prepared by adhering, for example, a fluid heat-resistant ink prepared using a solvent as necessary to a supporting substrate made of a film or cloth by an appropriate method such as an application method or an impregnation method. It can be formed by drying and holding it in a solidified state as needed.

As the above-mentioned supporting base material, an appropriate material such as a plastic film such as polyester, polyimide or fluororesin, or a cloth made of fibers such as polyamide or polyester can be used. The thickness of the heat-resistant ink layer in the solidified state provided on the support substrate is 100 μm or less from the viewpoint of thermal transferability,
Particularly preferably 0.1 to 50 μm, particularly preferably 1 to 20 μm,
It is not limited to this.

There is no particular limitation on the firing sheet to which ink information is to be applied by the thermal transfer method using the thermal transfer ink sheet, and a powder made of glass, other ceramics, or the like is shaped via an organic binder. An appropriate ceramic green sheet may be used.

The ink information applied to the baking sheet in the thermal transfer method using the thermal transfer ink sheet is arbitrary, and any ink information such as a print pattern, a picture pattern, a barcode pattern, etc. can be applied.

The firing sheet provided with the ink information is temporarily attached to an appropriate adherend such as a cathode ray tube or the like via an adhesive layer or the like as necessary, and the firing sheet is fired to obtain an organic binder or the like. Organic components such as the adhesive layer disappear, and the ink information provided by the firing sheet is fused while preserving to form a fired body, which is fixed to the adherend.

The thermal transfer ink sheet according to the present invention can be preferably used for various purposes such as painting on porcelain, glassware, enamel, etc., and providing an identification label, etc., through a firing sheet. Also glass or ceramic,
Assigning an identification label such as company name, lot number, product name, etc., coloring or color-coded pattern, bar code, etc. to products made of metal, etc., or transport pallets, especially heat-resistant substrates and prototypes such as ceramics It can also be used preferably.

[0027]

EXAMPLE 1 100 parts of phosphoric acid / zinc / alumina eutectic glass frit (parts by weight, the same applies hereinafter), 40 parts of carnauba wax, 30 parts of paraffin wax, 30 parts of ethylene / vinyl acetate copolymer, and average particles 0.5 μm diameter Cr ₂ O ₃ .CoO.Fe
100 parts of ₂ O ₃ .MnO ₂ type black pigment is uniformly mixed with a roll mill to prepare a heat-resistant ink, which is coated on a 6 μm-thick polyester film by a hot-melt gravure coating machine and cooled. Thus, an ink layer having a thickness of about 6 μm was formed to obtain a thermal transfer ink sheet.

Example 2 A thermal transfer ink sheet was obtained in the same manner as in Example 1 except that the amount of the phosphoric acid / zinc / alumina eutectic glass frit was changed to 150 parts.

Comparative Example In place of the phosphoric acid / zinc / alumina eutectic glass frit,
A thermal transfer ink sheet was obtained according to Example 1, except that a lead glass frit was used.

Evaluation Test An ink ribbon was formed from the thermal transfer ink sheets obtained in Examples and Comparative Examples, and a bar code pattern was printed on a firing sheet using a commercially available thermal transfer printer using the ink ribbon. Temporarily adhered to a glass plate via a glass plate, heated from room temperature to 440 ° C. at a rate of 10 ° C./min, kept at that temperature for 12 minutes, and then cooled to room temperature at a rate of 10 ° C./min. Then, a fired label having a black barcode pattern in a clear state was firmly fixed on a white background to obtain a glass plate. The organic components such as the binder and the adhesive layer were burned off by the firing.

The above-mentioned firing sheet was prepared by uniformly mixing 85 parts of glass powder having a softening point of 420 ° C., 15 parts of titania powder having an average particle diameter of 0.5 μm, and 20 parts of an acrylic resin binder together with 65 parts of toluene by a ball mill. To obtain a paste, which is spread on a polyester film treated with a release agent by a doctor blade method and dried to a thickness of about 100 μm.
After forming an m-shaped shape-retaining layer, an acrylic pressure-sensitive adhesive layer having a thickness of about 20 μm formed on a separator was laminated thereon, and the polyester film on the other surface was peeled off.

The following characteristics were examined for the glass plate with the fired label fixed thereon obtained above. Printability The printability when the barcode pattern was thermally transferred onto the firing sheet was examined.

Fixing Property The baked label fixed to the glass plate was strongly rubbed with nails, and the barcode pattern on the baked label and the fixing property of the baked label fixed to the glass plate were examined.

Readability The light reflectance of the baked label fixed to the glass plate was measured at a wavelength of 633.
It was measured via nm light to determine the readability of white and black barcodes.

The above results are shown in the following table together with the safety of the heat resistant ink.

Claims (3)

[Claims] 1. A thermal transfer ink sheet comprising a support substrate holding a heat-resistant ink containing at least a colored or transparent glass powder containing no lead and bismuth and an organic binder. 2. The thermal transfer ink sheet according to claim 1, wherein the glass powder has a softening point of 600 ° C. or lower, and the heat-resistant ink contains a heat-resistant colorant as a component. 3. The thermal transfer ink sheet according to claim 1, wherein the glass powder contains phosphoric acid, zinc and alumina as components.