JPH03178488A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To form a transfer image having high sensitivity and excellent in hot press resistance and abrasion resistance and to improve the preservability of a ribbon, in a thermal transfer recording medium provided with the first predetermined thermal transfer layer and the second predetermined thermal transfer layer, by adding inorg. pigment and a resin powder having a specific softening point to the first thermal transfer layer. CONSTITUTION:In a thermal transfer recording medium wherein a release layer based on wax having an m.p. or softening point of 70 - 120 deg.C, the first substantially colorless thermal transfer layer based on a thermoplastic sin having a glass transition point of 30 deg.C or higher and the second 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 and a colorant are provided on a support, inorg. pigment or a resin powder having a softening point of 100 deg.C or higher is added to the first thermal transfer layer to especially improve the preservability of a ribbon.

Description

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

[Conventional technology]

Conventionally, the 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. 63-5767).
No. 9); containing styrene/methyl methacrylate/butyl acrylate copolymer as the main component (JP-A No. 62-
No. 23779); Styrene/methacrylic ester copolymer/polymethacrylate/polyvinyl chloride resin and colorant laminated on a transparent protective layer consisting of a mixture of styrene/methacrylic ester copolymer and polyvinyl chloride resin (Japanese Unexamined Patent Application Publication No. 1989-1993)
No. 2-179992); having an ink layer made of a mixture of a (meth)acrylic acid ester polymer and a colorant laminated on a transparent protective layer made of a chlorinated polyolefin resin (Japanese Patent Application Laid-Open No. 63-42891) ) etc.

However, when conventional ink layers are used for clothing price tags, etc., they have the disadvantage that images bleed or become smeared due to the heat of hot pressing.

That is, in JP-A No. 63-57679, 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 around 0°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. Furthermore, the adhesion to the transfer target 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. Also, JP-A-62-23779, JP-A-62
No. 17992 and JP-A No. 63-42891 have the disadvantage that when Tg is increased, hot press resistance improves but sensitivity becomes slower, and when Tg is lowered, sensitivity becomes faster but hot press resistance deteriorates. Furthermore, since chlorinated polyolefin is used for the protective layer, the hot press resistance is not good.

[Problems to be Solved by the Invention] An object of the present invention is to provide a thermal transfer recording medium that is highly sensitive, can form transferred images with excellent hot press resistance and abrasion resistance, and has excellent ribbon storage stability. purpose.

[Means to solve the problem]

According to the invention, a melting point or softening point of 70 to 1
Release layer mainly made of wax at 20℃, glass transition point 3
A substantially colorless first thermal transfer layer mainly composed of a thermoplastic resin having a temperature of 0° C. or higher; a second layer mainly comprising a copolymer of at least an alkyl methacrylate and (meth)acrylonitrile having a glass transition point of 30° C. or higher and a colorant; There is provided a thermal transfer recording medium provided with two thermal transfer layers, characterized in that the first thermal transfer layer contains an inorganic pigment or a resin powder with a softening point of 100° C. or higher.

That is, the main feature of the present invention is that the first thermal transfer layer contains an inorganic pigment or a resin powder having a softening point of 100° C. or higher, thereby improving the storage stability of the ribbon.

As the inorganic pigment used in the present invention, any conventionally known inorganic pigment can be used. Examples of such pigments include silica, alumina, clay, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, iron oxide, tin oxide, and zinc sulfide.

In addition, fine resin powders with a softening point of 100°C or higher include thermoplastic resin powders such as polymethyl methacrylate, polyacrylonitrile, polyvinyl chloride, polystyrene, and fluororesins, and thermosetting resins such as urea resins, melamine resins, phenol resins, and silicone resins. Resin powder, average particle size 0.1-5μm
are preferably used. The amount added is 1 to 20% by weight.

Moreover, even if these inorganic pigments and fine resin powders are included in the second thermal transfer layer, not only are there no effects on the shelf life of the ribbon, but the thermal sensitivity is reduced, making it impossible to achieve the intended purpose of the present invention. Can not.

The present invention will be explained in more detail below.

The release layer in the present invention has a melting point or softening point of 70 to 12
Wax at 0°C, such as carnauba wax, montan wax, osichelite, microcrystalline wax, rice wax, ceresin wax, paraffin wax, polyethylene wax, Sasol wax, hydrogenated castor oil, etc., is the main component, and the thickness is 0°C. 1-31
na is preferred. Then, hot melt application or water,
It is formed by applying a solution dissolved or dispersed in 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.

Examples of thermoplastic resins with a temperature of 7 g and 30°C or higher used in the first thermal transfer layer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, acrylic acid, methacrylic acid, styrene, α-methylstyrene, acrylonitrile, methacrylatrile, vinyl chloride, and vinyl acetal. , vinyl acetal, copolymers thereof, and copolymers with other polymers (vinyl acetate, acrylic, ethylene, etc.). The first thermal transfer layer has a thickness of about 0.2 to 2 mm, and is obtained by coating and drying a coating liquid in which the resin is dissolved or dispersed in water or a solvent.

The glass transition point used for the second thermal transfer layer is 30°C or higher,
The copolymer consisting of at least alkimethacrylate and (meth)acrylonitrile 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 vinyl 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 resins. There are copolymers of

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.

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

The second thermal transfer layer has a thickness of about 1 to 3/JIB and can be formed by applying a coating solution dissolved or dispersed in water or a solvent and drying.

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, wholly aromatic polyamide film, polyether ether ketone film, polysulfonate film, etc. I can do it.

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.

The inorganic lubricant is preferably talc, mica powder, molybdenum disulfide, graphite, or the like, and has an average particle size of 0.1 to 5-5, preferably in the range of 5 to 2,011.

The organic lubricant has a melting point of 140°C or higher, and includes lithium stearate, magnesium stearate 11, calcium stearate, strontium stearate, barium stearate, calcium laurate, barium laurate, lithium 12-hydroxystearate, 1
Kinba soaps such as calcium 2-hydroxystearate and dibasic lead stearate, N,N'-ethylenebis-12-hydroxystearamide, N,N'-
Ethylene bislauric acid amide, N, N'-methylene bis stearic acid amide, N, N'-hexamethylene bis stearic acid amide, N, N'-hexamethylene bis oleic acid amide, N, N'-distearyl Examples include N-l substituted fatty acid amides such as adipic acid amide, N,N'-distearyl terephthalic acid amide, polytetrafluoroethylene, silicone resin, etc., and it is desirable to add them in an amount of 1 to 10 parts by weight. These are dissolved in the layer forming liquid or used in the form of fine particles of about 0.1 to 54 mm.

〔Example〕

The present invention will be explained below with reference to Examples and Comparative Examples.

Note that parts are parts by weight.

Example 1 The following composition solution was applied onto a 4.5 μm thick polyester film to provide a peeled W&layer with a 2 μm thick scratch.

Carnauba wax: 10 parts Toluene (dispersed in a ball mill for 24 hours): 90 parts A liquid having the primary composition was applied thereon to form a first thermal transfer layer having a thickness of 0.5 mm.

Fine silica powder (average particle size IIm) 2nd part n-butanol 10 copies water 70 copies Furthermore, apply the following composition liquid on top of it, Thickness 1.5μs A second thermal transfer layer was provided.

carbon black dispersion 30 copies Example 2 In Example 1, Change the release layer to the following composition, A strip tM with a thickness of 1- was provided.

A first thermal transfer layer having a thickness of 50 .mu.m was formed by coating 90 parts of carnauba wax on top of the following composition, and a thermal transfer recording medium was produced in the same manner as in Example 1.

Polyethyl methacrylate fine powder 2 parts n-butanol 10 parts water
70
Example 3 A thermal transfer recording medium was produced in the same manner as in Example 1 except that the second thermal transfer layer had the following composition.

30 parts of carbon black dispersion Example 4 A thermal transfer recording medium was prepared in the same manner as in Example 1 except that the second thermal transfer layer had the following composition.

Body emulsion (Tg 50°C, solid content 50%) 55 parts Carbon black dispersion 30 parts Comparative example 1
~4 Comparative thermal transfer recording media were prepared in the same manner as in Examples 1 to 4 except that silica or polymethyl methacrylate fine powder was removed from the first thermal transfer layer.

Furthermore, in each Example and Comparative Example, the following composition liquid was applied to the opposite side of the support to the side on which the thermal transfer layer was provided, and a thickness of 0.1-
A stick prevention layer is provided.

Silicone rubber (30%) 10 parts Toluene 90 parts Curing agent 0.1 part or more Using the thermal transfer recording medium prepared as above, a thermal transfer printer (line type head, applied energy 10 to 25 mj/m) was used.
The following test was conducted by printing on a transfer sheet.

Hot press test (JIS L 0850) Friction test (JIS L 0849) Scratch test (pencil hardness test) Storage (ribbon) test (The presence or absence of blocking was checked after 24 hours at 60°C in a rolled state.) Results are shown in Table-1. The transfer paper is coated paper (
A smoothness of 1000 seconds) was used.

Table 1 Note: Good image clarity: Good solidity and no blurred lines. And the lines are sharp.

No: Lines are not sharp Hot press resistance Good: No change Slightly poor: Slight transfer to cloth Bad: Image bleeding, large transfer to cloth Abrasion resistance Good: No change Bad: Staining occurs Storage stability No good double blocking occurs, bad double blocking occurs [Effects of the Invention] As explained above, the thermal transfer recording medium constructed according to the present invention has excellent hot press resistance, abrasion resistance, and scratch resistance, as well as particularly excellent storage stability. It is something.

Claims (1)

[Claims] (1) A release layer mainly made of wax with a melting point or softening point of 70 to 120°C on a support, a substantially colorless first thermal transfer layer mainly made of a thermoplastic resin with a glass transition point of 30°C or more, and glass. In a thermal transfer recording medium provided with a second thermal transfer layer mainly comprising a copolymer of at least an alkyl methacrylate and (meth)acrylonitrile having a transition point of 30° C. or higher and a colorant, the first thermal transfer layer has an inorganic pigment or a softening point. 1. A thermal transfer recording medium containing resin powder having a temperature of 100° C. or higher.