JP2001130150A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet which shows high printing sensitivity during printing by a thermal printer and a sharp impression and further, the capability to form an image-printed matter with an eminent metallic luster. SOLUTION: In the thermal transfer sheet 1 composed of at least a peelable anchor layer 3, a metal vapor-deposited layer 4 and an adhesive layer 5 laminated sequentially, the adhesive layer 5 characteristically contains a resin a carboxylic group or a maleic modified resin. Thus it is possible to enhance the adhesive properties between the metal vapor-deposited layer 4 and the adhesive layer 5 and ensure the upgraded adhesion between an object to which an image is transferred and the adhesive layer 5 and further solve the issues described in the purpose.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet for printing characters and designs having a metallic feeling such as metallic luster on a material to be transferred by a thermal transfer recording system. In particular, the present invention relates to a thermal transfer sheet which has high printing sensitivity at the time of printing with a thermal printer, has good print breakage, and provides a printed matter having excellent metallic luster.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a printed matter having a metallic luster, there has been known a hot stamping method in which a transfer foil is used to hot-press with a stamp made of metal or the like having a convex portion having the same shape as the printed matter. ing. As this transfer foil, for example,
A layer obtained by sequentially laminating a release layer, a vapor deposition anchor layer, a metal vapor deposition layer, and an adhesive layer on a base film of about 9 to 25 μm is used. Then, the desired image is transferred to the transfer object by pressing the adhesive layer side of the transfer foil against the transfer object such as paper and pressing the stamp heated to about 100 to 130 ° C. for several seconds from the base film side. This is an image recording method to be performed. However, the hot stamping method is not suitable for printing a small number of copies because it is necessary to produce a stamp made of metal or the like each time. In addition, precision processing such as halftone dots is required, and recording of a fine halftone image is difficult.

On the other hand, in recent years, a thermal transfer recording system using a thermal head and a thermal transfer ribbon has become widespread.
This method is suitable for printing a small number of copies and can easily record a halftone image by area gradation. Therefore, a transfer recording method using a thermal head instead of the stamp is desired. For example, JP-A-63-30288
In Japanese Patent Application Laid-Open Publication No. H11-115, an attempt has been made to thermally transfer a transfer foil used in a conventional hot stamping method using a thermal head using a thinner base film.

[0004]

However, the transfer foil of the above-mentioned thermal transfer method has a problem that the cohesion of the metal vapor-deposited layer is so strong that the cut of the print is poor and that the printed matter is liable to generate blemishes. On the other hand, if the adhesive strength between the substrate and the release layer is increased in order to improve the cut of the print, problems such as a decrease in transfer sensitivity and the occurrence of transfer failure due to separation between the adhesive layer and the metal deposition layer occur. There is a problem that occurs.

Therefore, in order to solve the above problems,
SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer sheet capable of forming a printed matter having high printing sensitivity at the time of printing with a thermal printer, good print breakage, and excellent metallic luster.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention provides a thermal transfer sheet having at least one release anchor layer, a metal deposition layer and an adhesive layer provided on one surface of a film substrate. By comprising a resin containing a carboxyl group or a maleic acid-modified resin in the adhesive layer, the adhesiveness between the metal deposition layer and the adhesive layer is high, and the adhesion between the transfer object and the adhesive layer is improved. Highly, the above problems could be solved. It is particularly preferred that the resin containing a carboxyl group is an acrylic acid copolymer resin. It is particularly preferable that the maleic acid-modified resin is a maleic acid-modified vinyl chloride-vinyl acetate copolymer resin. Further, the release anchor layer preferably contains a dye or a pigment as a coloring material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. FIG. 1 is a longitudinal sectional view showing one embodiment of the thermal transfer sheet having metallic luster of the present invention. In the thermal transfer sheet 1 shown in the figure, a heat-resistant layer 6 is provided on the back side of a film substrate 2, and on the front side of the film substrate 2, a release anchor layer 3, a metal deposition layer 4, an adhesive layer 5 is provided. Note that the heat-resistant layer 6 can be omitted as appropriate in some cases. In addition, the thermal transfer sheet of the present invention is usually used as a continuous belt-shaped thermal transfer ribbon, but can be used as a single sheet.

Hereinafter, each layer of the thermal transfer sheet of the present invention will be sequentially described. (Film substrate) The film substrate 2 of the thermal transfer sheet may be any material as long as it has a certain degree of heat resistance and strength conventionally known, for example, 0.5 to 50 μm.
m, preferably a polyester film, a polystyrene film, a polypropylene film, a polysulfone film, an aramid film, a polycarbonate film, a polyvinyl alcohol film, a cellophane and the like having a thickness of about 3 to 10 μm, and a polyester film is particularly preferable.

(Heat-Resistant Layer) In the thermal transfer sheet of the present invention, a heat-resistant layer 6 can be provided on the other surface of the film substrate to prevent adverse effects such as sticking and print wrinkles due to heat of the thermal head. As the resin for forming the heat-resistant layer, any conventionally known resin may be used. For example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride / vinyl acetate copolymer resin, polyether resin, polybutadiene resin, styrene / Butadiene copolymer resin, acrylic polyol, polyurethane acrylate, polyester acrylate,
Polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetopropionate resin, cellulose acetate butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide Resins, polyimide resins, polycarbonate resins, chlorinated polyolefin resins, and the like. In order to further improve heat resistance, a reaction product with various isocyanate curing agents or monomers or oligomers having an unsaturated bond may be used, and the curing method is not limited to curing means such as heating and irradiation with ionizing radiation.

[0010] Phosphoric acid esters, such as phosphoric acid esters, are added to or overcoated the heat-resistant layer made of these resins.
Silicone oils, graphite powders, silicone-based graft polymers, fluorine-based graft polymers, acrylic silicone graft polymers, acrylic siloxanes, silicone polymers such as aryl siloxanes, and the like, preferably polyols, for example, polyalcohol polymer compounds and polyalcohols This is a layer composed of an isocyanate compound and a phosphate compound, and it is more preferable to further add a filler. The heat-resistant layer, the resin described above, the slipperiness imparting agent, further filler, by a suitable solvent,
Dissolve or disperse to prepare an ink for forming a heat-resistant layer, and form it on the other surface of the film substrate by, for example, gravure printing, screen printing, or a reverse coating method using a gravure plate. It can be formed by applying and drying by means.

(Release anchor layer) The release anchor layer 3
Basically, it provides a base for metal deposition and protects the film substrate from heat during the deposition, and peels off between the film substrate and the release anchor layer by heating to form the outermost surface of the print. This is a layer for realizing metallic luster. After the transfer printing, the release anchor layer is transferred to the transfer receiving body together with the metal deposition layer, and is located above the metal deposition layer and is in close contact with the metal deposition layer to be a component of the recorded matter. Also, it is a layer that functions as a protective layer for improving the mechanical and chemical strength of the metal deposited layer such as abrasion and corrosion, and is a layer that is transparent enough to allow the metallic gloss of the metal deposited layer to be seen through.

Furthermore, the release anchor layer of the present invention has heat resistance so as to withstand the high heat generated by the thermal head and not to form a matted metal deposited layer, which is not received by the conventional hot stamping method. In addition, it is preferable to use a linear polymer instead of a crosslinked polymer, to eliminate the need for a curing treatment such as heat curing, and to easily provide a solution by simply applying and drying the solution. Specific examples of the material used for the release anchor layer having such heat resistance include a chlorinated polyolefin resin, a polyarylate resin, a norbornene-based hydrogenated resin, a polyimide resin, a polyamideimide resin, and a polyetheretherketone resin (PEEK). And polyether ketones such as polyether ketone resin (PEK),
Polyethersulfone resin, polysulfone resin, polyphenylene oxide resin and the like can be mentioned. These may be used alone or as a mixture. In particular, in the resin having the above heat resistance, by using at least one selected from chlorinated polyolefin resin, polyarylate resin, polyamide imide resin, norbornene-based hydrogenated resin, peeling from the film substrate Good
In addition, deformation during heating of the thermal head can be prevented, which is preferable.

The chlorinated polyolefin resin has a structure in which a chloro group is added to carbon of the polyolefin resin, and has a chlorination degree of 50% or more and a mass average molecular weight of 5,000.
It is preferably from 0 to 250,000, and if the degree of chlorination is less than 50%, the releasability from the film substrate decreases. If the weight average molecular weight is less than 5,000, deformation during heating of the thermal head is likely to occur, and if the weight average molecular weight is more than 250,000, the releasability from the film substrate is undesirably reduced.

The thickness of the release anchor layer is usually set in the range of 0.1 to 10 g / m ^{2 in} terms of coating amount. Thickness 0.1
If it is less than g / m ^2, it will not function as a release anchor layer,
If it exceeds g / m ² , the foil breakage at the time of printing becomes worse, and it is not suitable for halftone tone recording. Further, in the release anchor layer, for example, for the purpose of coloring the metal deposition layer with aluminum or the like, it is preferable to appropriately mix a cyan, magenta, yellow, black, and other hue coloring materials with a known dye or pigment or the like. .

(Metal Deposition Layer) The metal deposition layer 4 is formed by metallizing a metal such as aluminum, zinc, tin, chromium, gold, silver, or an alloy such as brass under vacuum such as vacuum deposition and sputtering. It is a metal thin film layer obtained. The thickness of the metal deposition layer is usually 100 to 1000 °.
(10-100 nm), preferably 200-500 °
(20 to 50 nm) is sufficient for obtaining metallic luster. If it is too thin, it does not reflect visible light to the extent that glossiness can be obtained, and if it is too thick, the foil breakage during printing deteriorates, making it unsuitable for halftone recording, and is uneconomical.

(Adhesive Layer) In the thermal transfer sheet of the present invention, the adhesive layer 5 is mainly composed of a resin containing a carboxyl group or a maleic acid-modified resin, and has high adhesion between the metal deposition layer and the adhesive layer. In addition, it is possible to form a printed matter having high adhesion between the transfer-receiving body and the adhesive layer, high printing sensitivity at the time of printing with a thermal printer, good print breakage, and excellent metallic luster. Examples of the resin containing a carboxyl group include acrylic acid, methacrylic acid, an ethylene-acrylic acid copolymer resin, and an ethylene-methacrylic acid copolymer resin.

The maleic acid-modified resin is obtained by replacing a part of the basic components with a maleic acid component in the reaction of a synthetic resin. For example, a maleic acid-modified ethylene-vinyl acetate copolymer resin And a maleic acid-modified vinyl chloride-vinyl acetate copolymer resin, a maleic acid-modified polyolefin resin, and the like. The resin containing a carboxyl group or the maleic acid-modified resin is 50%
Those having a softening point of ~ 120 ° C are preferred. This is because if the softening point is too low, blocking tends to occur in the winding and storing of the thermal transfer sheet, and if the softening point is too high, the adhesion to the object to be transferred during thermal transfer is weakened.

For the adhesive layer, the above-mentioned resin containing a carboxyl group or a maleic acid-modified resin can be used alone. The adhesive layer is made of a thermoplastic resin having a glass transition temperature or a softening point of 50 to 120 ° C., or a melting point of 50 to 120 ° C.
1% of the above resin containing a carboxyl group or maleic acid-modified resin
These can be mixed and used. Other thermoplastic resins include ethylene-based copolymers such as ethylene-vinyl acetate copolymer resins, ethylene-acrylic acid copolymer resins, and ethylene-methacrylic acid copolymer resins, which are copolymers of ethylene with other polymerizable monomers. Polymer, polyethylene resin, polypropylene resin, polyvinyl acetate, polyester resin, polyurethane resin, styrene resin, acrylic resin, polyamide resin, polyvinyl alcohol, polyvinyl acetate, petroleum resin, phenol resin, maleic resin, etc., or Elastomers such as synthetic rubber such as polyisoprene rubber, styrene-butadiene rubber, and butadiene-acrylonitrile rubber, and natural rubber. In addition, as the wax, carnauba wax, paraffin wax, microcrystalline wax, ester wax, Fuscher Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, whale wax, Ibota wax,
Wool wax, shellac wax, candelilla wax,
Petrolactam, partially modified wax, fatty acid ester,
Various known waxes such as fatty acid amides can be used.

The required thickness of the adhesive layer varies depending on the surface shape of the material to be transferred. However, as long as the glossiness of the metal deposition layer and the cut-off property of the foil are not impaired, the thinner the adhesive layer, the higher the printing sensitivity and printability. This is preferred from the viewpoint of fixability and resolution of the resulting image. For example, the coating amount is in the range of 0.05 to 5.0 g / m ² , preferably 0.1 to 3.0 g / m ² . 0.05
If it is less than g / m ² , sufficient adhesive strength cannot be obtained. On the other hand, if it exceeds 5 g / m ² , excessive energy is required to melt the adhesive layer, and foil breakage is undesirably reduced.

(Release Layer) The thermal transfer sheet of the present invention does not require a release layer because the release anchor layer has the function of a release layer, but the release property between the film substrate and the release anchor layer is insufficient. If it is, a release layer can be provided between the film substrate and the release anchor layer. As the release layer, for example, carnauba wax, paraffin wax,
Microcrystalline wax, ester wax, Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax, whale wax, ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, partially modified wax, fatty acid ester, fatty acid amide Various waxes can be used.

The release layer mainly contains the above-mentioned wax, and a resin other than the wax may be mixed and used if the releasability from the film substrate is appropriate. Such resins include, for example, rubber resins such as polyisoprene rubber, styrene butadiene rubber, butadiene acrylonitrile rubber, acrylate resins, polyvinyl ether resins, polyvinyl acetate resins, and vinyl chloride resins.
Vinyl acetate copolymer resin, polystyrene resin, polyester resin, polyamide resin, polyimide resin, polychlorinated olefin resin, polycarbonate,
Polyvinyl butyral-based resins and the like can be mentioned. The thickness of the release layer is preferably in the range of 0.01 to 5.0 g / m ^{2 in} terms of the amount of coating at the time of drying. When it is less than 0.01 g / m ^2, it does not function as a release layer, and when it exceeds 5.0 g / m ² ,
Foil breakage at the time of printing is reduced, and particularly, halftone recording cannot be performed well, and the foil durability is reduced.

The thermal transfer sheet of the present invention configured as described above is most suitable for a thermal printer using a thermal head, but can also be used as a transfer foil for a conventional hot stamping method. In addition, since it has excellent resolution, it is suitable for use in printing images such as characters and designs as an aggregate of minute patterns, and can impart metallic luster to these images. Therefore, as a density gradation expression method, an intermediate density can be reproduced by expressing the density gradation by the size of the transfer portion according to the size of the halftone dot, that is, by using the area gradation. In addition, as a method of the area gradation, a screen pattern or the like known in the printing field using a grain, a brick pattern, or the like can be used in addition to a halftone dot.

[0023]

Next, the present invention will be described more specifically with reference to examples. In the following description, “parts” or “%” is based on mass unless otherwise specified. (Example 1) A polyethylene terephthalate film having a thickness of 6.0 µm was used as a film substrate, and one surface of the film was made of a silicone-modified polyester.
The same applies hereinafter) to form a heat-resistant layer of 0.2 g / m ² . Next, a release anchor layer having the following composition was applied to the other surface so as to have a thickness of 0.7 g / m ² when dried. Then, on the release anchor layer, an aluminum metal vapor-deposited layer having a thickness of 300 ° was further formed by a vacuum vapor-deposition method, and an adhesive layer having a thickness of 0.8 g / m ² upon drying was further formed on the metal vapor-deposited layer. The thermal transfer sheet of Example 1 of the present invention was obtained by coating with a coating liquid.

Release anchor layer coating liquid Chlorinated polypropylene resin 20 parts Polyester resin 1 part Methyl ethyl ketone / toluene (mass ratio 1/1) 79 parts

Coating solution for adhesive layer Vinyl chloride-vinyl acetate copolymer resin 10 parts Maleic acid-modified vinyl chloride-vinyl acetate copolymer resin 2 parts Methyl ethyl ketone / toluene (mass ratio 1/1) 44 parts

Example 2 The heat transfer of Example 2 was carried out in the same manner as in Example 1 except that the formation of the release anchor layer (0.7 g / m ² ) was changed to the following coating solution. A sheet was prepared. Release anchor layer coating liquid Chlorinated polypropylene resin 20 parts Polyester resin 1 part Yellow dye / magenta dye (mass ratio 7/1) 1 part Methyl ethyl ketone / toluene (mass ratio 1/1) 78 parts

Example 3 The thermal transfer sheet of Example 3 was prepared in the same manner as in Example 1 except that the formation of the adhesive layer (0.8 g / m ² ) was changed to the following coating solution. Was prepared. Adhesive layer coating liquid polyester resin 10 parts Ethylene-acrylic acid copolymer resin 10 parts Methyl ethyl ketone / toluene (mass ratio 1/1) 20 parts

Comparative Example 1 The thermal transfer sheet of Comparative Example 1 was prepared in the same manner as in Example 1 except that the formation of the adhesive layer (0.8 g / m ² ) was changed to the following coating solution. Was prepared. Coating liquid for adhesive layer Vinyl chloride-vinyl acetate copolymer resin 20 parts Methyl ethyl ketone / toluene (mass ratio 1/1) 80 parts

(Evaluation Method) The thermal transfer sheets of the above Examples and Comparative Examples were used, a polyethylene terephthalate film having a thickness of 125 μm was used as an object to be transferred, and a 300 dpi line type head was used as a thermal head. Printing was performed using a test pattern at an energy of 0.40 mJ / dot, and the following evaluation was performed.

(Specular glossiness of printed matter) With respect to each printed matter obtained under the above conditions, the degree of specular gloss was visually inspected for mattness in a printed portion, particularly a solid portion. The criteria for the evaluation are as follows. ：: The printed surface is not matted at all when solid printing is performed. Δ: Matting is observed on a part of the printing surface when solid printing is performed. ×: Most or all of the printing surface is matted when solid printing is performed.

(Resolution) The sharpness of the edge portion of the printed portion of each print obtained under the above conditions was visually observed and examined. The criteria for the evaluation are as follows. ：: The sharpness of the edge portion of the printed portion is excellent. Δ: The sharpness of the edge portion of the printed portion is slightly inferior. ×: Poor sharpness at the edge of the printed area

(Adhesiveness) With respect to each of the prints obtained under the above conditions, the cellophane tape was rubbed and reciprocated once with a thumb and adhered, and then peeled off at a peeling angle of 180 °, and the adhesiveness was visually observed. Was evaluated. The criteria for the evaluation are as follows. ：: The image is hardly peeled off from the print. ×: The image was easily peeled off from the print.

The evaluation results are as shown in Table 1 below.

[Table 1]

[0034]

As described above, the thermal transfer sheet of the present invention is
On one surface of the film substrate, at least, in a thermal transfer sheet provided with a release anchor layer, a metal deposition layer and an adhesive layer sequentially, a resin containing a carboxyl group in the adhesive layer,
Alternatively, by containing a maleic acid-modified resin, the adhesion between the metal deposition layer and the adhesive layer is high, and the adhesion between the transfer object and the adhesive layer is high, and the printing sensitivity when printing with a thermal printer High print quality, good print breakage, and excellent metallic luster.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a thermal transfer sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet 2 Film base material 3 Peeling anchor layer 4 Metal deposition layer 5 Adhesive layer 6 Heat resistant layer

Claims (4)

[Claims] 1. A thermal transfer sheet having at least one release anchor layer, a metal deposition layer and an adhesive layer sequentially provided on one surface of a film substrate, wherein the adhesive layer contains a carboxyl group-containing resin or a maleic acid-modified resin. A thermal transfer sheet comprising: 2. The thermal transfer sheet according to claim 1, wherein the resin containing a carboxyl group is an acrylic acid copolymer resin. 3. The thermal transfer sheet according to claim 1, wherein the maleic acid-modified resin is a maleic acid-modified vinyl chloride-vinyl acetate copolymer resin. 4. The thermal transfer sheet according to claim 1, wherein the release anchor layer contains a dye or a pigment as a coloring material.