JPH0280295A - thermal transfer recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal transfer recording medium useful for thermal transfer ribbons or clothing labels.

[Prior Art] Conventionally, the ink layer of a thermal transfer recording medium includes an ink layer containing an emulsified resin with a minimum film forming temperature of 40° C. or higher (Japanese Patent Application Laid-Open No. 63-57679); A type having a heat-sensitive transfer layer consisting of a colorant and a water-soluble resin (JP-A-60-61290); coated with an ink consisting of a heat-melting binder and six colorants dispersed in an aqueous solution of a water-soluble polymer. (Japanese Unexamined Patent Publication No. 60-212388); Those whose main components are styrene/methyl methacrylate/butyl acrylate copolymer (Japanese Unexamined Patent Application No. 82-23779); Styrene/methacrylic acid ester It has an ink layer made of a mixture of styrene/methacrylic acid ester copolymer/polymethacrylate/polyvinyl chloride resin and a colorant laminated on a transparent protective layer made of a mixture of copolymer and polyvinyl chloride resin. Things (JP-A-62-1
No. 79992); 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.

[Problems to be Solved by the Invention] However, when these conventional ink layers are used for clothing labels, etc., the image tends to fall off during dry cleaning, and the heat of hot pressing causes image bleeding and stains. There were drawbacks.

That is, among the conventional technologies mentioned above, those containing styrene or acrylate as a copolymerization component tend to cause images to come off during dry cleaning, and methacrylic acid ester alone has low thermal sensitivity, and furthermore, the use of chlorinated polyolefin in the protective layer It is also unsuitable for dry cleaning.

The present invention was made in view of these circumstances, and an object of the present invention is to provide a thermal transfer recording medium that can form a transferred image that does not cause image bleeding or staining due to the heat of a hot press and that can withstand dry cleaning. This is the purpose.

[Means for Solving the Problems] The present inventors have conducted repeated research to solve the above problems, and as a polymer material used for the ink layer,
We have discovered that it is effective to select a specific combination of polymers, leading to the present invention.

That is, the present invention provides (1) a thermal transfer recording medium having, on a support, an ink layer mainly composed of a methyl methacrylate homopolymer or a methyl methacrylate copolymer having a glass transition point of 80° C. or higher, polyvinyl alcohol, and a colorant; (2) A thermal transfer recording medium having, on a support, an ink layer containing as main components a homopolymer of methyl methacrylate or a copolymer thereof, a polyester polyol having an OH value of 25 or more, and a colorant.

The thermal transfer recording medium of the present invention is composed of a support, a contact layer provided as necessary, and an ink layer.

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, polysulfone film, etc. can.

The adhesive layer provided as necessary in the present invention is mainly composed of a rubber resin and wax, and examples of the rubber resin include styrene/butadiene copolymer, butadiene/acrylonitrile copolymer, butyl rubber, polyisoprene, Examples of waxes such as neoprene, natural rubber, and cyclized rubber include carnauba wax, montan wax, paraffin wax, microcrystalline wax, low molecular weight polyethylene wax, and stearic acid. The compounding ratio of rubber resin and wax is 1:0.1~2 (
Weight ratio), thickness is 0.1-1μ, preferably 0.8-1μ
It is 0.7μ.

The ink layer used in the present invention is composed mainly of (1) a homopolymer of methyl methacrylate or a methyl methacrylate copolymer with a glass transition point of 80° C. or higher, polyvinyl alcohol, and a colorant, or (2) methyl methacrylate. homopolymer or copolymer thereof and OH number 25
The main ingredients are the above polyester polyol and a colorant.

In (1), the homopolymer of methyl methacrylate or its copolymer has a glass transition point (Tg) of 80°C or higher, and is used as an emulsion by emulsion polymerization or as a finely dispersed mechanically in water using a ball mill, sand mill, etc. . The average particle size at this time is preferably 3 μm or less.

In the case of a copolymer, it is not preferable to use a copolymer component that can be immersed in a solvent (percrene) used for dry cleaning, and alkyl methacrylates other than methylnystal, methacrylic acid, vinyl chloride, vinylidene chloride, etc. are preferable. be. If the Tg is less than 80° C., the hot press properties will deteriorate and images will smudge or stain.

The polyvinyl alcohol preferably has a saponification degree of 70 to 100% and a polymerization degree of 200 to 2,000. The content of polyvinyl alcohol is preferably 0.05 to 0.2 parts by weight per 1 part by weight of polymethyl methacrylate or its copolymer.

In addition, in (2), the homopolymer of methyl methacrylate or its copolymer has a glass transition point (Tg) of 80
Molecular ffi 10.000 to 500.0 at temperatures above ℃
00 is preferred. In the case of a copolymer, it is not preferable to use a copolymerization component that can be attacked by a solvent (percrene) used in dry cleaning, and alkyl methacrylates other than methyl ester, methacrylic acid, vinyl chloride,
Vinylidene chloride and the like are preferred. If the Tg is less than 80° C., the hot press properties will deteriorate, and image bleeding and staining will occur due to heat.

The polyester polyol has a Tg of 60°C or higher and an O
Those having an H value of 25 or more have particularly excellent dry cleaning properties. If the Tg is less than 60°C, the hot pressability will be extremely poor, which is not preferable. Preferably 10 at 70°C or higher
It is below 0°C (sensitivity is slow above 100°C). The blending ratio of the homopolymer of methyl methacrylate or its copolymer and the polyester polyol is preferably about 1:0.1 to 1 (by weight). However, the polyester polyol used has a lower Tg than polymethyl methacrylates.

It is preferable to use the methyl methacrylate homopolymer or its copolymer in the form of particles, and when used in a film-formed state, it curls significantly and is difficult to handle.

The particle size is preferably 3 μm or less on average. More than 3μ°
This results in uneven heat transfer, making it impossible to obtain clear images.

The coloring agent in the ink layer is preferably carbon black, other inorganic pigments, or organic pigments, and the amount is 10 to 2 with respect to the total amount of the ink layer.
About 0% by weight is preferable. The thickness of the ink is preferably about 3 to 5 microns.

In addition, a resin that is not affected by toy cleaning and has a low Tg can be added to the ink layer as necessary for the purpose of improving sensitivity, etc., but the amount should be kept to a minimum so as not to reduce hot pressability. . These resins include polyvinyl chloride, polyvinylidene chloride, polyester, polyol, polyethylene and the like.

[Example] EXAMPLES The present invention will be explained in more detail by way of Examples below.

Example 1 Polymethyl methacrylate emulsion (Tg 105°C
, solids content 50%) 20 parts by weight polyvinyl alcohol 10
% aqueous solution (degree of saponification 88%, degree of polymerization 500) 10 parts by weight Carbon black dispersion liquid (SD 9020 manufactured by Dainippon Ink Co., Ltd.) A composition liquid consisting of 2.5 parts by weight was applied onto a 4.5μ polyester film, An ink layer of 4 μm (thickness after drying) was provided.

Example 2 Methyl methacrylate/ethyl methacrylate copolymer emulsion (7g 85°C, solid content 50%) 20 parts by weight polyvinyl alcohol 10% aqueous solution (Ken polarity 98.5%, degree of polymerization 1000) 5ffi
A composition liquid consisting of 1 part carbon black dispersion (5D9020 manufactured by Dainippon Inn+ Co., Ltd.) 2.5iTfff was applied onto a 4.5μ polyester film to form an ink layer of 4μ (thickness after drying).

Example 3 Example 1 except that a methyl methacrylate/vinyl chloride copolymer emulsion (7 g, 95°C, solid content 50%) was used instead of the polymethyl methacrylate emulsion of Example 1.
A 4 μm ink layer was provided in the same manner as above.

Example 4 An ink layer of 4μ was provided in the same manner as in Example 1 except that a methyl methacrylate/vinylidene chloride copolymer emulsion (Tg 80°C, solid content 50%) was used instead of the polymethyl methacrylate emulsion in Example 1. .

Example 5 Methyl methacrylate/methacrylic acid/ethylene copolymer emulsion (T g 90°C, solid content 509
An ink layer having a thickness of 4 μm was provided in the same manner as in Example 1 except that 6) was used.

Comparative Example 1 Polymethyl methacrylate emulsion (Tg 105°C
, solid content 50%) 20 parts by weight carnauba wax emulsion (solid content 30%) 3.3 parts by weight Carbon black dispersion (SD 9020 manufactured by Dainippon Ink Co., Ltd.) 2.5 parts by weight It was coated onto a polyester film to provide a 4μ ink layer.

Comparative Example 2 An ink layer of 4μ was provided in the same manner as in Example 1, except that a methyl acrylate/methyl methacrylate copolymer emulsion (7 g, 60°C, solid content 50%) was used instead of the polymethyl methacrylate emulsion in Example 1. .

Comparative Example 3 An ink layer of 4μ was provided in the same manner as in Example 1, except that a methyl methacrylate/vinylidene chloride copolymer emulsion (Tg 50°C, solid content 50%) was used instead of the polymethyl methacrylate emulsion in Example 1. .

Furthermore, the following composition liquid was applied to the side opposite to the ink side of each Example and Comparative Example to provide a stick prevention layer having a thickness of 0.1 μm.

Silicone rubber (30%) 10 parts by weight Toluene 90 parts by weight Curing agent
A thermal transfer printer (line type head,
Appropriate printing energy (sensitivity) was determined by printing on synthetic paper (egg oiled synthetic paper) with an applied energy of 10 to 25 mj/a II2), and a transferred image was created, and the following tests were conducted.

Dry cleaning test (JIS L 0860) Hot press test (JIS L 0850.100℃)
Friction Test (JIS L 0849) The above results are summarized in Table 1 below.

Table 1 [Note] Good: There is almost no change in the quantitative image, and there is blurring or a decrease in image density, making it difficult to read.

Example 6 Polymethyl methacrylate (Tg 105°C) 10 parts by weight Polyester polyol (OHHSO 37g 90°C) 7 parts by weight Carbon black 3.4 parts by weight Methyl ethyl ketone
A composition liquid consisting of 79.6 parts by weight was milled in a ball mill for 24 hours.
After time dispersion, it was coated on a 4.5μ polyester film to form an ink layer of 4μ (thickness after drying).

Example 7 20 parts by weight of polymethyl methacrylate (TgLO5°C) and 1 part by weight of isopropyl alcohol were dispersed in a ball mill to obtain a dispersion liquid (A) having an average particle size of 2 μm.

Polyester polyol (OHHSO37g90℃) 20 parts by weight Carbon black 10 parts by weight Isopropyl alcohol
A composition liquid consisting of 70 parts by weight was dispersed in a ball mill for 24 hours to obtain a carbon dispersion liquid (B).

(A) 50 parts by weight, (B) 35 parts by weight were mixed, (C
) '12 cloth on 4.5 μ polyester film, 4
An ink layer of μ (thickness after drying) was provided.

Example 8 4 was prepared in the same manner as in Example 7, except that methyl methacrylate/ethyl methacrylate copolymer (7 g, 85°C) was used instead of polymethyl methacrylate.
．． A 4μ ink layer was provided on a 5μ polyester film.

Example 9 In Example 7, polyester polyol (OHHSO
A 4μ ink layer was provided on a 4.5μ polyester film in the same manner as in Example 2, except that a polyester polyol having an OH value of 40.7g and 85°C was used instead of 3Tg (90°C).

Example 10 The following composition solution was applied onto a 4.5μ polyester film to form an adhesive layer with a thickness of 0.5μ.

Styrene/butadiene copolymer 5 parts by weight Carnauba wax 5 parts by weight Toluene
90 parts by weight of the composition of Example 6 was applied onto this adhesive layer to form an ink layer with a thickness of 4 μm.

Example 11 The following composition solution was applied onto a 4.5μ polyester film to provide an adhesive layer with a thickness of 0.5μ.

Butadiene/acrylonitrile copolymer 5! Ii parts by weight polyethylene wax 5 parts by weight toluene
90 parts by weight of the liquid composition of Example 7 was applied onto this adhesive layer to form an ink layer with a thickness of 4 μm.

Further, the following composition liquid was applied to the surface opposite to the ink surface of each example to provide a stick prevention layer having a thickness of 0.1 μm.

Silicone rubber (30%) 10 parts by weight Toluene 90 parts Hardening agent
0.1 parts by weight Comparative Example 4 An ink layer having a thickness of 4 μm was provided in the same manner as in Example 6 except that polyester polyol was reduced to 20 parts by weight except for polymethyl methacrylate.

Further, the above-mentioned stick prevention layer was provided on the opposite side to the ink side.

Comparative Example 5 A 4 μm ink layer was provided in the same manner as in Example 6 except that the polyester polyol was removed and polymethyl methacrylate was used in an amount of 20 parts by weight, and the above-mentioned stick prevention layer was provided on the opposite side to the ink surface.

Comparative Example 6 In Example 6, styrene/methyl methacrylate copolymer (Tg9G°C) was used instead of polymethyl methacrylate.
) was used in the same manner as in Example 6, and the anti-stick layer was further provided on the opposite side to the ink side.

Comparative Example 7 The same procedure as in Example 6 was carried out except that polymethyl acrylate (Tg 3° C.) was used instead of polymethyl methacrylate, and the above-mentioned anti-stick layer was further provided on the surface opposite to the ink surface.

Comparative Example 8 In Example 6, instead of polyester polyol, O
The same procedure as in Example 6 was carried out except that a polyester polyol having an H value of 5 and a Tg of 70° C. was used, and the above-mentioned anti-stick layer was further provided on the surface opposite to the ink surface.

Using the thermal transfer recording medium created as described above, a thermal transfer printer (line type head, applied energy 1O
~25 mj/es2) on synthetic paper (egg oiled synthetic paper) to determine the appropriate printing energy (sensitivity), a transferred image was created, and the following tests were conducted.

Dry cleaning test (JIS L 0880) Hot press test (JIS L 0850.100℃)
Friction Test (JIS L 0849) The above results are summarized in Table 2 below.

[l+] Curl Good: Flat Medium: Both ends are lθ ~ 20- ■ Highly lifted: The ink falls off to form a round cylinder Good: No falling off A little: A lot of it occurs on both ends: Others occur on the entire surface Good: Haton No change: Bad: There is image blurring or a decrease in image density, making it difficult to read.

[Effects of the Invention] As explained above, according to the configuration of the present invention, it is possible to produce a thermal transfer recording medium that forms a transferred image with excellent hot pressability and dry cleaning performance.

Claims (2)

[Claims] (1) A thermal transfer recording medium comprising, on a support, an ink layer containing as main components a methyl methacrylate homopolymer or a methyl methacrylate copolymer having a glass transition point of 80° C. or higher, polyvinyl alcohol, and a colorant. (2) A thermal transfer recording medium having, on a support, an ink layer containing as main components a homopolymer of methyl methacrylate or a copolymer thereof, a polyester polyol having an OH value of 25 or more, and a colorant.