JPH02277690A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To enhance the hot press resistance, friction resistance and ribbon preservability by providing a release layer based on wax on a support and providing a thermal transfer layer based on a specific copolymer, a thermoplastic resin and a colorant thereon. CONSTITUTION:A release layer based on wax having an m.p. or softening point of 70 - 120 deg.C is provided on a support and a thermal transfer layer based on a copolymer consisting of at least alkyl methacrylate and (meth)acrylonitrile having a glass transition point of 30 deg.C or higher, a thermoplastic resin having a glass transition point of 30 deg.C or lower and a colorant is provided thereon. By this method, the sensitivity of a recording medium can be enhanced and a transfer image excellent in hot press resistance and friction resistance can be formed. In this case, when the m.p. or softening point of the release layer is lower than 70 deg.C, heat energy at the time of transfer is consumed in the melting of wax and the transfer of the thermal transfer layer is made bad. When said m.p. or softening point is higher than 120 deg.C, releasability at the time of transfer becomes inferior. When the glass transition point of the copolymer used in the thermal transfer layer is lower than 30 deg.C, the resolving power of a transfer image is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thermal transfer recording medium particularly suitable for clothing price tags.

[Prior Art] Conventionally, a thermal transfer layer (ink layer) of a thermal transfer recording medium has an ink layer containing an emulsified resin with a minimum film forming temperature of 40°C or higher (Japanese Patent Laid-Open No. 83-5767).
No. 9); containing styrene/methyl methacrylate/butyl acrylate copolymer as the main component (JP-A No. 62-
No. 23779); Styrene/methacrylate copolymer/polymethacrylate/polyvinyl chloride resin and coloring laminated on a transparent protective layer made of a mixture of styrene/methacrylate copolymer and polyvinyl chloride resin (Japanese Patent Application Laid-Open No. 82-179992); consists of a mixture of a (meth)acrylic acid ester polymer and a coloring agent laminated on a transparent protective layer made of a chlorinated polyolefin resin. There are those having an ink layer (Japanese Patent Application Laid-Open No. 3-42891).

[Problems to be Solved by the Invention] When conventional ink layers are used for clothing price tags, etc., they have the disadvantage that image bleeding and staining occur due to the heat of hot press.

In other words, in Japanese Patent Application Laid-open No. Sho Ei3-57679, resins with a minimum film forming temperature of 40°C or higher do not necessarily have good heat resistance;
Blocking, image smearing, and staining occur at temperatures around 00°C. Furthermore, emulsions of resins with a high glass transition point (Tg) such as polymethyl methacrylate have a high minimum film forming temperature and are inferior in thermal sensitivity. In particular, hot pressing at 180° C. or higher causes image bleeding and staining. In addition, the adhesion to the object to be transferred is poor, and the image is likely to fall off if rubbed strongly. Furthermore, if a wax with a low melting point is used as a binder, the image will bleed and become stained during hot pressing, making it impossible to use it for price tags for clothing. JP-A-62-23779, JP-A-62
-17992 and JP-A-03-42891 have the disadvantage that increasing Tg improves hot press resistance but slows down sensitivity, and lowering Tg increases sensitivity but deteriorates hot press resistance. Since chlorinated polyolefin is used for the protective layer, it has poor hot press resistance.

Accordingly, the present invention provides a thermal transfer recording medium that has high sensitivity, can form transferred images with excellent hot press resistance and abrasion resistance, and has excellent ribbon storage stability.

[Means for Solving the Problems] The present invention provides (1) a material with a melting point or softening point of 70 to 12 on a support;
A release layer mainly composed of wax at 0°C is provided, and a copolymer consisting of at least an alkyl methacrylate and (meth)acrylonitrile with a glass transition point of 30'C or higher is provided thereon, and a thermoplastic resin with a glass transition point of 30°C or lower. and (2) a release layer mainly consisting of Fuchs having a melting point or softening point of 70 to 120°C, and a glass transition point of 30°C or higher on the support. a substantially colorless first thermal transfer layer mainly comprising a copolymer comprising at least an alkyl methacrylate and (meth)acrylonitrile; a copolymer comprising at least an alkyl methacrylate and (meth)acrylonitrile having a glass transition point of 30° C. or higher; and glass. It is characterized by sequentially providing a second thermal transfer layer mainly composed of a thermoplastic resin having a transition point of 30° C. or less and a coloring agent.

The release layer in the present invention has a melting point or softening point of 70 to 12
The wax is mainly composed of 0°C wax such as carnauba wax, montan wax, osikelite, microcrystalline wax, rice wax, ceresin wax, paraffin wax, polyethylene wax, Sasol wax, hardened castor wax, etc., and has a thickness of 0°C. 1~3μ
m is preferred. Then, it is formed by hot melt coating or by coating a solution dissolved or dispersed in water or an organic solvent.

Such a release layer improves the transfer efficiency during thermal transfer and provides a clear image. At the same time, a wax layer is formed on the surface of the transferred image, and the action of the wax improves hot press resistance (making it difficult to transfer to other surfaces). and improves wear resistance.

If the melting point or softening point of the release layer is lower than 70° C., thermal energy during transfer is consumed in melting the wax, impairing transfer of the thermal transfer layer. Furthermore, if the melting point or softening point is higher than 120°C, the peelability during transfer will be poor.

The copolymer having a glass transition point of 30° C. or higher and consisting of at least an alkyl methacrylate and (meth)acrylonitrile used in the thermal transfer layer may include various methacrylates, such as methyl methacrylate, ethyl methacrylate,
It is obtained by copolymerizing at least one of propyl methacrylate, butyl methacrylate, etc., and acrylonitrile or methacrylate trile. This copolymer can also contain other monomers as copolymerization components within the scope of the present invention.

This copolymer must have a glass transition temperature of 30°C or higher. If the temperature is lower than 30°C, the film forming properties will be better.
The transferred image becomes less sharp and the resolution decreases.

The thermoplastic resin with a glass transition temperature of 30°C or less is preferably one that has good adhesion to the object to be transferred, such as acrylic resin, vinyl acetate resin, vinylidene chloride resin, polyester resin, or various types of resin. There are copolymers.

The mixing ratio of the copolymer of alkyl methacrylate and (meth)acrylonitrile with a glass transition temperature of 30°C or higher and the thermoplastic resin with a glass transition temperature of 30°C or lower is 10 parts by weight of the former and 0.5 to 5 parts by weight of the latter. It is. If the amount is less than this range, the thermal transfer layer will easily fall off, and if it is more than this range, blocking will likely occur.

The thickness of the thermal transfer layer in the first invention of the present invention and the second thermal transfer layer in the first invention is about 1 to 3 μm, and the thickness of the first thermal transfer layer in the second invention is 0.2 to 2 μm.
That's about it.

These thermal transfer layers can be formed by applying a coating solution dissolved or dispersed in water or a solvent and drying.

Pigments and dyes such as carbon black, red iron, Lake Red C1 Fast Sky Blue, benzidine yellow, phthalocyanine green, phthalocyanine blue, direct dyes, oil dyes, and basic dyes can be used as colorants, and can be applied throughout each ink layer. It is preferable to add about 10 to 20% by weight.

The support used in the present invention is a plastic film with a thickness of about 3 to 10 μm, such as polyester film, polycarbonate film, polyimide film,
Examples include wholly aromatic polyamide film, polyetheretherketone film, and polysulfone film.

In addition, a lubricant may be added to the release layer and/or the first thermal transfer layer of the present invention. Particularly preferred are inorganic lubricants and organic lubricants having a melting point of 140°C or higher.

Inorganic lubricants include talc, mica powder, molybdenum disulfide, graphite, etc., with an average particle size of o, 1 to 5μ, and 5 to 20
Add in a range of % by weight.

The organic lubricant has a melting point of 140°C or higher, and includes lithium stearate, magnesium stearate, calcium stearate, strontium stearate, barium stearate, calcium laurate, barium laurate, lithium 1.2-hydroxystearate, 1.
．． Metal soaps such as calcium 2-hydroxystearate and dibasic lead stearate, N,N'-ethylenebis-1,2-hydroxystearamide, N,N'
-Ethylenebislauric acid amide, N,N'-methylenebisstearic acid amide, N,N'-ethylenebisstearic acid amide, N,N'-hexamethylenebisstearic acid amide, N,N'-hexamethylene bisoleic acid amide, N,N'-distearyladipic acid amide,
N-substituted fatty acid amides such as N,N'-distearyl terephthalic acid amide, polytetrafluoroethylene, silicone resin, etc. are added in two parts of 1 to 10% by weight. These are dissolved in the layer forming liquid or used in the form of fine particles of about 0.1 to 5 μm.

[Example code] The present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 The following composition solution was applied onto a 4.5 μm thick polyester film to provide a 2 μm thick release layer.

Parts are parts by weight.

Carnauba wax 10 parts Toluene (dispersed for 24 hours in a ball mill) 90 parts A liquid having the following composition was applied thereon to form a thermal transfer layer with a thickness of 2 μm.

Ethyl methacrylate/acrylonitrile copolymer emulsion (Tg 70°C, solid content 50%
) 60 parts n-butyl acrylate/methyl methacrylate copolymer emulsion (7 g 20°C, solid content 50%) 20 parts carbon black dispersion 20 parts Example 2 The release layer in Example 1 was changed to the following composition, and the thickness was changed. 1μm
A release layer was provided.

Carnauba wax 90 parts Ethylene/vinyl acetate copolymer (hot melt coating at 120° C.) 10 parts The following composition was coated thereon to form a thermal transfer layer with a thickness of 2 μl.

n-Butyl methacrylate/acrylonitrile copolymer emulsion (Tg 50°C, solid content 50%) 70 parts Ethyl methacrylate/ethyl acrylate copolymer emulsion (7g 20°C, solid content 50%) 10 parts Carbon black dispersion 20 parts Example 3 The following composition solution was applied onto the release layer of Example 2 to a thickness of 0.5
A first thermal transfer layer of μI was provided.

n-Butyl methacrylate/acrylonitrile copolymer emulsion (Tg 50°C, solid content 5
0%) 20 parts n-butanol 10 parts water
Further, 70 parts of the following composition was applied thereon to form a second thermal transfer layer having a thickness of 1.5 μm.

n-Butyl methacrylate/acrylonitrile copolymer emulsion (Tg5 (1°C, solid content 50%) 60 parts Ethyl methacrylate/ethyl acrylate copolymer emulsion (7g 20°C, solid content 50%) 10 parts Carbon black dispersion 30 parts Example 4 A thermal transfer recording medium was produced in the same manner as in Example 3 except that the first thermal transfer layer had the following composition.

n-Butyl methacrylate/acrylonitrile copolymer emulsion (Tg 30°C, solid content 50%) 20 parts n-butanol 10 parts water
70 copies Example 5 A thermal transfer recording medium was prepared in the same manner as in Example 3 except that the second thermal transfer layer had the following composition.

Ethyl methacrylate/acrylonitrile/ethyl acrylate copolymer emulsion (Tg 40°C, solid content 50%) 60 parts Polyester emulsion (TglO°C, solid content 30%) 10 parts Carbon black dispersion 30 parts Example 6 Second in Example 3 A thermal transfer recording medium was prepared in the same manner except that the composition of the thermal transfer layer was changed to the following.

Methyl methacrylate/n-butyl methacrylate/acrylonitrile copolymer emulsion (Tg50'C1 solid content 50%
) 55 parts Vinyl acetate/ethyl acrylate copolymer emulsion (7 g 20°C, solid content 50%) 15 parts Carbon black dispersion 30 parts Comparative Example 1 The same procedure as in Example 1 was carried out except that the thermal transfer layer was changed to the following composition. A thermal transfer medium was prepared for comparison.

Ethyl methacrylate/acrylonitrile copolymer emulsion (Tg 70°C, solid content 50%), 80 parts Carbon black dispersion 20 parts Comparative Example 2 The same procedure as in Example 3 was carried out except that the first thermal transfer layer was changed to the following composition. A thermal transfer medium was prepared for comparison.

n-butyl methacrylate emulsion (Tg 20°C, solid content 50%) 20 parts n-butanol 10 parts water
70 parts Comparative Example 3 A comparative thermal transfer medium was prepared in the same manner as in Example 3 except that the second thermal transfer layer had the following composition.

n-Butyl methacrylate emulsion (Tg 20°C, solid content 5096) Go part ethyl methacrylate/ethyl acrylate copolymer emulsion (1'g 20°C, solid content 50%) 10
Carbon black dispersion 30 parts In each of the Examples and Comparative Examples, the following composition liquid was applied to the opposite side of the support to the side on which the thermal transfer layer was provided, to provide a stick prevention layer with a thickness of 0.1 μm.

Silicone rubber (30%) 10 parts Toluene 90 parts Hardening agent
A thermal transfer printer (line type head, applied energy 10 to 25IIlj/ra
m2), printing was performed on the transfer sheet and the following tests were conducted.

Hot press test (JIS L 0850) Friction test (JIS L 0849) Scratch test (
Pencil hardness test) Storage (ribbon) test (50°C, 24°C when rolled up)
Check the presence or absence of blocking after a certain period of time) The results are shown in the table below. Note that coated paper (smoothness: 1000 seconds) was used as the transfer paper.

Table 1 [Effects of the Invention] As explained above, according to the structure of the present invention, a thermal transfer recording medium having excellent hot press resistance, abrasion resistance, scratch resistance, and ribbon storage stability can be obtained.

Note) Image 1. Brightness is good, solidity is good, and there are no blurred lines. And lines are good and lines are poor Hot press resistance Good: No change Slightly poor: Slight transfer to fabric Bad 2. Image bleeding, transfer to fabric High abrasion resistance Good: No change Bad: Stain Good shelf life, no blocking occurs, bad blocking occurs

Claims (2)

[Claims] (1) A release layer mainly composed of wax with a melting point or softening point of 70 to 120°C is provided on the support, and on top of the release layer, at least an alkyl methacrylate with a glass transition point of 30°C or higher and (
1. A thermal transfer recording medium comprising a thermal transfer layer mainly comprising a copolymer of meth)acrylonitrile, a thermoplastic resin having a glass transition point of 30° C. or less, and a colorant. (2) A release layer on the support mainly consisting of wax with a melting point or softening point of 70 to 120°C, and a release layer mainly consisting of a copolymer of at least alkyl methacrylate and (meth)acrylonitrile with a glass transition point of 30°C or higher. a colorless first thermal transfer layer, a second thermal transfer layer mainly consisting of a copolymer consisting of at least an alkyl methacrylate and (meth)acrylonitrile having a glass transition point of 30° C. or higher, a thermoplastic resin having a glass transition point of 30° C. or lower, and a colorant; A thermal transfer recording medium characterized in that layers are sequentially provided.