JPH023391A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To form a printing picture having excellent fixing and high quality even to a medium to be transferred made of a metal such as aluminum by incorporating at least one of an ethylene-acrylic acid copolymer and an ethylene- alkyl acrylic acid copolymer in an overcoating layer. CONSTITUTION:An overcoating layer is formed onto a substrate through at least one layer of a thermosoftening coloring material layer, and the overcoating layer includes the copolymer of ethylene and acrylic acid shown by formula CH2=CR-COOH (where R represents a hydrogen atom or a 1-4C alkyl group). The copolymer is selected from the group of an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer and an ethylene-butyl acrylic acid copolymer. The compounding ratios of acrylic acid, methacrylic acid and butyl acrylic acid are preferably brought to 5-60wt.% to total weight with ethylene respectively. The layer thickness of the overcoating layer is preferably brought within a range of 0.5-2.5mum. Accordingly, excellent fixing is displayed even to a medium to be transferred made of a metal such as aluminum, thus forming a printing picture having a high grade.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a thermal transfer recording medium, and more specifically, a high-quality printed image with good fixability even on metal transfer media such as aluminum. The present invention relates to a thermal transfer recording medium that is capable of forming images and achieving high print quality even when performing high-speed printing.

[Prior Art and Problems to be Solved by the Invention] In recent years, with the spread of thermal transfer devices such as word processors, transfer media using thermal transfer recording media consisting of a heat-softening layer laminated on a support have been developed. Thermal transfer methods that form printed images on paper have come to be widely adopted.

In addition, in this thermal transfer method, it is possible to form high-quality prints not only on transfer paper, which has conventionally been commonly used as a transfer medium, but also on metal transfer media such as aluminum. A recording medium was desired.

However, in conventional thermal transfer recording media, it is widely known that an overcoat layer is provided on the support via an ink layer in order to protect the ink layer or to improve fixation to transfer paper. ing.

However, using such a thermal transfer recording medium,
When printing is transferred onto a metal transfer medium, there is a problem in that the fixability of the transferred print to the sheet is extremely poor, and at the same time, when the printing speed is increased, the print quality is significantly reduced.

This invention was made based on the above circumstances.

That is, an object of the present invention is to form a high-quality printed image with good fixability even on a metal transfer medium such as aluminum, and also to achieve high print quality even when performing high-speed printing. The object of the present invention is to provide a thermal transfer recording medium that can be realized.

[Means for Solving the Problems] In order to solve the problems described above, the present inventor has made extensive studies and found that a specific overcoat layer is applied to the support through a heat-softening coloring material layer. The thermal transfer recording medium provided with
The inventors have arrived at the present invention by discovering that it is possible to print with excellent fixing properties on metal transfer media such as aluminum, and to print with high quality even in high-speed printing.

That is, the invention according to claim 1 provides a heat-sensitive transfer recording medium in which an overcoat layer is provided on a support through at least one heat-softening coloring material layer, wherein the overcoat layer contains ethylene and the formula (1) A heat-sensitive transfer recording medium characterized by containing a copolymer with acrylic alcohol represented by the formula %() (where R is a hydrogen atom or an alkyl group).

The invention according to claim 2 is the thermal transfer recording medium according to claim 1, wherein in the formula (I), R is a hydrogen atom or an alkyl group having 1 or more and 4 or less carbon atoms.

The invention according to claim 3 provides that the copolymer or ethylene-
2. The thermal transfer recording medium according to claim 1, which is at least one copolymer selected from the group of acrylic acid copolymers, ethylene-methacrylic acid copolymers, and ethylene-phthyl acrylic acid copolymers.

The heat-sensitive transfer recording medium of the present invention is formed by laminating at least a heat-softening coloring material layer and an overcoat layer in this order on a support.

Note that the thermal transfer recording medium of the present invention may have other layers within a range that does not impair its characteristics. for example,
The heat-softening coloring material layer may be laminated on the support with another layer such as a release layer interposed therebetween, or an intermediate layer or the like may be laminated under the overcoat layer.

Next, the structure of this heat-sensitive transfer recording medium will be described in detail in the order of the support, the heat-softening coloring material layer, and the overcoat layer.

Support The support in the thermal transfer recording medium of the present invention preferably has good heat resistance strength and high dimensional stability.

The materials include, for example, papers such as plain paper, condenser paper, laminated paper, and coated paper; resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimide; and a composite of paper and resin film. Metal sheets such as aluminum foil are preferably used.

The thickness of the support is usually 30 ILm or less, preferably 2
~: l (within the range of lpm. The thickness of the support is 30 g
If it exceeds m, thermal conductivity may deteriorate, leading to deterioration of printing quality.

In the heat-sensitive transfer recording medium of the present invention, the structure on the back side of the support may be arbitrary, and for example, a hara kink layer such as an anti-sticking layer may be provided.

Heat-softening coloring material layer The heat-softening coloring material layer formed between the support and the overcoat layer described in detail below contains at least a coloring material and a heat-melting substance.

Examples of the coloring material include pigments such as inorganic pigments and organic pigments, and dyes.

Examples of the inorganic pigments include titanium dioxide, carbon fluff, zinc oxide, Prussian flu, cadmium sulfide, iron oxide, and chromates of lead, zinc, barium, and calcium.

Examples of the organic pigments include azo, thioindigo, an1-laquinone, an1-anthrone, triphendioxazine pigments, hat dye pigments, phthalocyanine pigments, such as copper phthalocyanine and its derivatives, such as quinacridone pigments. can be mentioned.

The dyes include acid dyes, direct dyes, disperse dyes>1,
Examples include oil-soluble dyes and metal-containing oil-soluble dyes.

The content of the coloring material in the heat-softening coloring material layer is usually 5.
-40% by weight, preferably 10-30% by weight.

Specific examples of the heat-melting substances include vegetable waxes such as carnauba wax, wood wax, auriculie wax, and Nispar wax; animal waxes such as beeswax, insect wax, shellac wax, and spermaceti wax; paraffin wax, microcrystal wax, and polyethylene wax. , petroleum waxes such as ester waxes and oxidized waxes, and mineral waxes such as montan wax, onkelite and ceresin, and in addition to these waxes, palmitic acid, stearic acid, margaric acid, etc. and higher fatty acids such as hehenyl alcohol: higher alcohols such as palmityl alcohol, stearyl alcohol, behenyl alcohol, marcanyl alcohol, myricyl alcohol, and eicosanol: higher alcohols such as cetyl balmitate, myricyl palmitate, cetyl stearate, and myricyl stearate Fatty acid ester: acetamide,
Amides such as propionic acid amide, valmitic acid amide, stearic acid amide and amide wax, and higher amines such as stearylamine, behenylamine and valmitylamine are included.

These may be used alone or in combination of two or more.

Among these, preferred is a wax whose melting point is within the range of 50 to 1008 C as measured using Yanagimoto IAJP-2.

The content of the heat-melting substance in the heat-softening coloring material layer is:
Usually, 5 to 4
0% by weight, preferably 10-30% by weight
is within the range of

The thermosoftening coloring material layer may contain a thermoplastic resin together with the coloring material and the thermofusible substance. Examples of the thermoplastic resin include an ethylene copolymer, a polyamide 1-based resin, a polyester resin, Resins such as polyurethane resins, polyolefin resins, acrylic resins, vinyl chloride resins, cellulose resins, rosin resins, ionomer resins, and petroleum resins, natural rubber, styrene phtadiene rubber, inbrene rubber, chloroprene rubber, and dienes. Elastomers with copolymers:
Rosin derivatives such as estercam, rosin maleic resin, rosin phenol resin, and hydrogenated rosin; and softening points of phenol resins, terpene resins, cyclopentadiene resins, aromatic hydrocarbon resins, etc. 50 to 150°
Examples include polymeric compounds of C.

Among the various thermoplastic resins, acrylic resins, diene copolymers, and ethylene copolymers are preferred. This is because by using these, it is possible to obtain a thermal transfer recording medium with particularly good high-speed printing quality.

Preferred thermoplastic resins will be explained below.

Examples of the acrylic resin include acrylic resins obtained by polymerizing monobasic carboxyl alcohols such as (meth)acrylic acid or their esters, and at least one type of compound that can be copolymerized with these. I can do it.

Examples of the calfone alcohol or its ester include (
(meth)acrylic acid, (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid isopropyl ester, (meth)acrylic acid methyl ester, (meth)acrylic acid isophthyl ester, (
meth)acrylic acid amyl ester, (meth)acrylic acid hexyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid-2-ethylhexyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid dodecyl ester, Examples include (meth)acrylic acid hydroxymethyl ester and (meth)acrylic acid 1-oxyethyl ester.

Further, examples of the above-mentioned copolymerizable compounds include vinyl acetate, vinyl chloride, vinylidene chloride, anhydrous 7-rein chu,
Fumaric anhydride, styrene, 2-methylstyrene, chlorostyrene, acrylonitrile, vinyltoluene, N-methylol (meth)acrylamide, N-phthoxymethyl (
Examples include meth)acrylamide, vinylpyridine and N-vinylpyrrolone.

Examples of the diene copolymer include phtadiene-styrene copolymer, phtadiene-styrene-vinylpyricine copolymer, phtadiene-acrylonitrile copolymer, chloroprene-styrene copolymer, and chloroprene-acrylonitrile copolymer.

Examples of the ethylene copolymer include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-isobutyl acrylate copolymer, and ethylene-acrylic acid. Examples include copolymers, ethylene-hinyl alcohol copolymers, ethylene-vinyl chloride copolymers, and ethylene-acrylic acid metal salt copolymers.

These may be used alone or in combination of two or more.

The content of the thermoplastic resin in the thermosoftening coloring material layer is:
It is usually within the range of 1 to 40% by weight, preferably 3 to 40% by weight.
It is within the range of 20% by weight, more preferably 5 to 15% by weight.
Within the range of % by weight.

In addition to the above-mentioned components, the heat-softening coloring layer may contain a surfactant such as a polyoxyethylene chain-containing compound in order to adjust the releasability.

Furthermore, inorganic or organic fine particles (metal powder, silica gel, etc.) or oils (linseed oil, mineral oil, etc.) can also be added.

The heat-softening coloring material layer can be formed using hot melt coating method, water-based coating method,
Coating can be done using a coating method using an organic solvent.

The thickness of the heat-softening coloring material layer coated on the support by such a coating method is usually 0.3 to 0.3B. wm, preferably 0.5 to 5.0. It is within the range of wm.

The second part of the heat-softening coloring material layer formed in this way is:
For example, an overcoat layer, which will be described in detail below, is laminated via an intermediate layer or directly.

Overcoat layer - One of the important points in this invention is that the ethylene-acrylic acid copolymer and The object of the present invention is to provide an overcoat layer containing at least one of ethylene-alkyl acrylic acid copolymers.

The overcoat layer in this invention can form a high-quality printed image with good fixability even on a metal transfer medium such as aluminum, and can also print with high quality even when performing high-speed printing. It has the action or function of forming an image.

The above action or function of the overcoat layer mainly depends on the ethylene-acrylic acid copolymer and the ethylene-alkyl acrylic acid copolymer contained in the overcoat layer.
brought about by at least one.

The ethylene-acrylic acid copolymer may be a random copolymer or a flock copolymer, but is not particularly limited, and is preferably a random copolymer.

The blending ratio of the acrylic acid is usually 2 to 90% by weight, preferably 5 to 60% by weight, based on the total amount of ethylene and acrylic acid.

Further, VFR of an ethylene-acrylic acid copolymer that can be suitably used in the present invention.

(Melt flow rate) is usually 1 to 2000g71
0 minutes, preferably 5 to 1000 g/10 minutes.

Furthermore, regarding the softening point, the softening point (Vicat) of ethylene-acrylic acid copolymer is 40 to 1 (10°C
1. Preferably, one having a temperature of 50 to 90°C can be used.

In general, commercially available products (Yukalon-EAA series [manufactured by Mitsubishi Yuka Co., Ltd.], etc.) can also be suitably used.

As the ethylene-alkyl acrylic acid copolymer,
There is no particular restriction, but R in the formula (I) is preferably an ethylene-alkyl acrylic acid copolymer having an alkyl group having 1 or more and 4 or less carbon atoms, and more preferably ethylene - methacrylic acid copolymers and ethylene-phthyl acrylic acid copolymers.

As with the ethylene-acrylic acid copolymer, the ethylene-methacrylic acid copolymer may be a random copolymer or a flock copolymer, and there is no particular restriction, or a random copolymer may be used. Combination is preferable.

The blending ratio of the methacrylic acid is usually 2 to 90% by weight with respect to the content of the ethylene and methacrylic acid,
Preferably it is 5 to 60% by weight.

Moreover, MFR of the ethylene-methacrylic acid copolymer that can be suitably used in the present invention.

(Melt flow rate) is usually 1 to 500 g/lD
minutes, preferably 5 to 4 (1Dg/10 minutes).

Furthermore, regarding the softening point, the softening point (Bikaut) of ethylene-methacrylic acid copolymer is 50 to 120℃,
Preferably, one having a temperature of 60 to 110°C can be used.

In general, commercially available products such as the Uclair series (manufactured by DuPont, USA) can also be suitably used.

As with the ethylene-acrylic acid copolymer, the ethylene-butyl acrylic acid copolymer is not particularly limited, and may be a random copolymer or a flock copolymer; however, a random copolymer may be used. Polymers are preferred.

The blending ratio of the butyl acrylic acid is usually 2 to 95% by weight based on the content of the ethylene and butyl acrylic acid.
It is preferably 5 to 60% by weight.

Further, the VFR (melt flow rate) of the ethylene-butyl acrylic acid copolymer that can be suitably used in the present invention is normal.

1-2000 g/10 min, preferably 5-1000
g/10 minutes.

Furthermore, regarding the softening point, the softening point (Vicat) of ethylene-phthyl acrylic acid copolymer is 40 to 120.
'c, preferably 50 to 90°C.

In addition, the ethylene-acrylic acid copolymer, ethylene-acrylic acid copolymer,
As the methacrylic acid copolymer and the ethylene-butyl acrylic acid copolymer, copolymers in which the hydrogen atoms of the carboxyl groups present in these molecular chains are partially replaced with metal atoms, such as sodium or zinc, are also suitable. It can be used for

These may be used alone or in combination of two or more.

Further, the overcoat layer may contain other components such as a heat-melting substance, a thermoplastic resin, etc. in addition to the above-mentioned components as long as they do not impede the object of the present invention.

For these, the same materials as those in the heat-softening coloring material layer described above can be used.

Furthermore, the overcoat layer may contain a coloring material as long as it does not impede the object of the present invention.

The overcoat layer is formed by applying a coating method similar to the coating method that can be used to apply the heat-softening coloring material layer, and applying the overcoat layer directly onto the heat-softening coloring material layer or by applying another intermediate layer. It is possible to apply the coating through the . The layer thickness of the OOHARNY-1 layer applied in this manner is usually in the range of 0.3 to 3.5 gm, preferably in the range of 0.5 to 2.5 gm.

In addition, in the thermal transfer recording medium of the present invention, a conventionally known release layer or anchor layer may be provided between the support and the heat-softening coloring material layer, as long as it does not impede the object of the present invention. An intermediate layer may be provided between the heat-softening coloring material layer and the overcoat layer.

After each layer is coated in this manner, it is optionally subjected to a drying process, a surface smoothing process, etc., and then cut into a desired shape to obtain the thermal transfer recording medium of the present invention.

The heat-sensitive transfer recording medium thus obtained can be used in the form of a tape or sheet, for example.

The heat-sensitive transfer method using this heat-sensitive transfer recording medium is not different from the usual heat-sensitive transfer recording method, and will be explained by taking as an example the case where the most typical thermal head is used as the heat source.

First, the heat-softening layer of the heat-sensitive transfer recording medium and a metal transfer medium, such as aluminum foil, are brought into close contact with each other, and if necessary, a heat pulse is further applied from the back side of the aluminum foil using a platen, and a heat pulse is applied using a heat head. give,
The heat-softening layer corresponding to the desired print or transfer pattern is locally heated.

The temperature of the heated portion of the thermosoftening layer increases, and the heated portion is quickly softened and transferred onto the transfer medium.

At this time, since the heat-softening coloring material layer contains at least a heat-melting substance, it is quickly peeled off from the support even when printing is performed at high speed, and the overcoat layer is made of ethylene-acrylic acid. Since it contains at least one of a polymer and an ethylene-alkyl acrylic acid copolymer, it exhibits good fixing properties even on metal transfer media such as aluminum and forms high-quality printed images. I can do it.

[Example] Next, Examples and Comparative Examples of the present invention will be shown to further specifically explain the present invention.

(Example 1) The following heat-softening coloring material layer composition was applied on a polyethylene terephthalate film having a thickness of 3.5 gm to a dry film thickness of 2.0 gm.
gm to form a heat-softening coloring material layer.

The coating was carried out using a hot melt method using a wire bar.

Arsenic wax: 30% by weight Ethylene-vinyl acetate copolymer: 200% by weight Carphone fluff: 20% by weight The coated footwear composition was coated on the heat-softening coloring material layer to a dry film thickness of 1.5 Bm to form an overcoat layer to produce a heat-sensitive transfer recording medium of the present invention.

The overcoat footwear composition was applied by dissolving or dispersing the overcoat footwear composition in methyl ethyl ketone and using a wire bar.

Overcoat - Ethylene-acrylic acid copolymer (Yukalon "manufactured by Mitsubishi Yuka Co., Ltd.") 30% by weight oxidized wax 40% by weight ethylene-vinyl acetate copolymer ...The thermal transfer recording medium obtained at 30% by weight was attached to a commercially available printer (24-dot serial head, applied energy: 30 IIJ/head), and the alphabet was transferred onto aluminum foil (film thickness 20 pLm, surface treated to be non-glossy). (Printing) was performed.

The resulting prints were evaluated for their fixability to aluminum foil and print quality.

The results are shown in Table 1.

The print quality and print fixation were evaluated as follows.

That is, printing was carried out under the condition of the printer's platen pressure of 700 g and the printing speed was varied as shown in Table 1, and the print quality, scumming, and trailing of the obtained printed images were visually evaluated. .

In addition, adhesive tape ["Post-It Tape", manufactured by Jujutsu 3M ■] was attached to the printed image, and then it was peeled off, and the printed image remaining on the aluminum foil was observed to evaluate the fixation. did.

In Table 1, the meanings of the symbols are as follows.

For use ■ Shellfish ○ ... No voids or smudges, and excellent sharpness.

△・・・・・・There are some voids.

×: There are many voids, and the characters are difficult to read.

△・・・・・・Ink peels off slightly.

×・・・・・・Printing has peeled off and cannot be read.

(Example 2) In the above-mentioned Example 1, the following overcoat footwear composition was used in place of the Ohaco-1 henetone composition used in the above-mentioned Example 1. It was carried out in the same manner.

The results are shown in Table 1.

Overcoat ethylene-methacrylic acid copolymer with Cuclell (manufactured by DuPont): 25% by weight Paraffin wax: 65% by weight Ethylene-vinyl acetate copolymer: 10% by weight (comparison) Example 1) In the same manner as in Example 1, except that the overcoat footwear composition shown below was used in place of the overcoat footwear composition used in Example 1. A thermal transfer recording medium was manufactured, and the obtained thermal transfer recording medium was evaluated in the same manner as in Example 1 above.

The results are shown in Table 1.

(Comparative Example 2) A heat-sensitive transfer recording medium was produced in the same manner as in Example 1, except that no layer was provided on the heat-softening colorant layer. The heat-sensitive transfer recording medium was evaluated in the same manner as in Example 1 above.

The results are shown in Table 1.

(Wood page, blank space below) Overcoat paraffin wax: 65% by weight Ethylene-vinyl acetate copolymer: 35% by weight.

Claims (3)

[Claims] (1) In a thermal transfer recording medium comprising an overcoat layer provided on a support via at least one heat-softening coloring material layer, the overcoat layer contains ethylene and the formula (
I) A thermal transfer recording medium characterized by containing a copolymer with acrylic acid represented by CH_2=CR-COOH (I) (wherein R is a hydrogen atom or an alkyl group). (2) The thermal transfer recording medium according to claim 1, wherein in the formula (I), R is a hydrogen atom or an alkyl group having 1 or more and 4 or less carbon atoms. (3) The copolymer is at least one copolymer selected from the group of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and ethylene-butyl acrylic acid copolymer. 1. The thermal transfer recording medium according to 1.