JPS63162287A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer recording medium imparting a transfer image superior in fastness to abrasion, by a method wherein a lubricating protective layer is provided between a substrate and a hot melt ink while the hot melt ink contains a specific low-crystallinity or amorphous resin in a hot melt binder more than a specific quantity. CONSTITUTION:A thermal transfer recording medium is composed by coating a hot melt ink on a substrate. A lubricating protective layer mainly composed of a wax is provided between the substrate and the hot melt ink, which contains 30 pts.wt. or more of a resin having a crystallinity as low as an endotherm caused by crystalline melting is not more than 10 cal/g or amorphous properties, a glass transition point of 30-100 deg.C, a softening point of 40-120 deg.C in 100 pts.wt. of a hot melt binder. If a transfer printing is conducted on a recording paper with the use of this thermal transfer recording medium, the surface of the transferred image is protected by the lubricating protective layer mainly composed of the wax with good slip properties and, additionally, has remarkably good fastness to abrasion such as rubbing and scratching because the hot melt ink layer has superior adhesion to the recording paper and contains the low- crystallinity or amorphous glass-form resin with high shear strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording medium that provides a transferred image with excellent friction fastness.

[Conventional technology and its problems]

The thermal transfer recording method uses a thermal transfer recording medium formed by coating at least one layer of heat-fusible ink on a sheet-like base material, and stacks this thermal transfer recording medium so that the hot-fusible ink layer is in contact with recording paper. In addition, this is a recording method in which an ink layer is heated and melted by a heating head from the base material side of a thermal transfer recording medium to obtain a transferred image on recording paper. This method has been widely used in recent years because the apparatus used has low noise, is excellent in operability and maintainability, and plain paper can be used as recording paper.

However, the transferred image formed by such a thermal transfer recording method has a disadvantage in that the fastness of the transferred image is not sufficient because it is easily smudged or peeled off when its surface is rubbed or scratched.

Therefore, as a technique to solve this problem, a method has been proposed in which a heat-crosslinkable resin compound is added to the heat-melting ink layer (Japanese Patent Laid-Open No. 6O-212389).
L. This method has poor storage stability of the thermal transfer recording medium itself because the heat-crosslinkable resin compound is thermally unstable, and when a heat-crosslinkable resin compound that is highly stable against heat is used. had the disadvantage that a sufficient crosslinking reaction did not occur during transfer, and the expected fastness could not be obtained.

It has also been proposed to provide a colorless heat-fusible layer mainly made of wax with a penetration of 5 or less, which becomes an abrasion-resistant layer when a transferred image is formed on recording paper between the base material and the hot-fusible ink layer. (Japanese Unexamined Patent Publication No. 61-787692). However, although this method is somewhat effective against low-load friction such as from erasers and fingers, it is relatively brittle because the wear-resistant layer mainly uses wax of 5 or less, and cannot be used under high loads. It is completely ineffective against friction, causing damage such as cracking and peeling of the wear-resistant layer. Therefore, in the fields of use such as commuter passes, labels, certificates, etc., where transferred images are required to have a high degree of abrasion fastness, the fastness of the transferred images has not been sufficient.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of conventionally proposed methods and to provide a thermal transfer recording medium that provides a transferred image with excellent abrasion fastness.

[Structure of the invention]

The thermal transfer recording medium of the present invention is a thermal transfer recording medium formed by coating a heat-fusible ink on a base material, which has a lubricating protective layer mainly composed of wax between the base material and the hot-fusible ink, and , the heat-melting ink has a glass transition point of 30 to 100
℃, a softening point of 40 to 120℃, and an endothermic amount due to melting of crystals of 10 cal/g or less, containing 30 parts by weight or more per 1 part by weight of 100 parts of the heat-melting binder. It is characterized by:

It has been found that by using the thermal transfer recording medium of the present invention, the friction fastness of the transferred image is significantly improved. That is, when the thermal transfer recording medium of the present invention is used to transfer onto a recording paper, the surface of the transferred image is protected by a lubricating protective layer with good slip properties mainly composed of wax, and a heat-melting ink layer. Because it contains a low-crystalline or amorphous glass-like resin that has excellent adhesion to recording paper and high shear strength, it has been found to have extremely good durability against friction such as rubbing and scratching. Served.

The present invention will be explained in more detail below.

Examples of the base material of the thermal transfer recording medium of the present invention include papers such as capacitor paper and glassine paper, and films such as polyester, polycarbonate, polyimide, polyamide, polyethylene, and polypropylene. The thickness of the base material is preferably in the range of about 2 to 20 microns. Further, in order to prevent sticking, a heat-resistant protective layer made of a heat-resistant resin or the like may be provided on the surface opposite to the surface on which the lubricating protective layer and the heat-melting ink layer are applied.

As the lubricating protective layer, wax is mainly used. Briefly, heat-melting inks include paraffin wax, microcrystalline wax, polyethylene wax, carnauba wax, candelilla wax, rice wax, montan wax, beeswax, lanolin, oxidized paraffin wax, oxidized microcrystalline wax, and oxidized polyethylene wax. Conventionally known waxes are preferably used as binders regardless of their penetration. The waxes mentioned above may be used alone or in an appropriate combination of two or more kinds. In addition to wax, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyethylene,
Resins such as petroleum resins may also be added. Further, in order to improve lubricity, a small amount of oily substance such as silicone oil or mineral oil may be added. The melting point of the lubricating protective layer is 40
It is desirable that the temperature is in the range of ~120°C. Further, the thickness of the lubricating protective layer is preferably in the range of 0.1 to 4 .mu.m.

The heat-melting ink layer is composed of a heat-melting binder and a colorant as main components. The thermofusible binder has a glass transition point in the range of 30 to 100°C, preferably 40 to 80°C, and a softening point of 40 to 120°C, preferably 5
30 parts by weight of a low-crystalline or amorphous resin that is in the range of 0 to 110°C and has an endothermic amount of 10 cal/g or less due to melting of crystals per 100 parts by weight of the heat-melting binder.
Contains at least part by weight. However, even if the resin exceeds the above characteristic values, it can be used if it is brought within the above characteristic values by adding a plasticizer or the like.

If the glass transition point is less than 30°C, a sufficient effect on the friction fastness of the transferred image will not be obtained, and if it exceeds 100°C, the softening point of the resin will become too high, resulting in poor transferability. Furthermore, if the content is less than 30 parts by weight, sufficient effects on the friction fastness of the transferred image cannot be obtained.

The glass transition point and endothermic amount were measured using a differential scanning calorimeter (
DSC), and the softening point is measured by the ring and ball method.

Examples of the low crystalline or amorphous resin include polystyrene, polyacrylic acid, polyacrylic ester,
Styrene-acrylic acid copolymer, styrene-acrylic acid ester copolymer, polymethacrylic acid ester, polyacrylamide, polyvinyl ester, unsaturated polyester, polyvinyl chloride, ketone resin, terpene resin, hydrogenated terpene resin, coumaron resin, Examples include rosin ester, rosin modified resin, maleic acid resin, and the like. These resins may be used alone or in combination of two or more.

Among the heat-melting binders, other than the above-mentioned resins, for example,
paraffin wax, microcrystalline wax,
Waxes such as polyethylene wax, carnauba wax, candelilla wax, rice wax, montan wax, beeswax, lanolin, oxidized paraffin wax, oxidized microcrystalline wax, oxidized polyethylene wax, stearic acid, lauric acid, palmitic acid, lead stearate , higher fatty acids such as barium stearate, zinc stearate, stearate stearate,
Alternatively, derivatives such as metal salts and esters thereof, resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymers, and saturated polyesters, etc. can be used.

In addition, as coloring agents, Disazo Yellow G, Disazo Yellow GR, Fast Yellow FGL, Isoindolinone Yellow 2GLT, Biosolone Orange G1 Palkan Orange, Zapon Fast Orange RR, Naphthol Carmine FB, Fast Scarle Soto, Naphthol Red 23, Pyrazolone Red B, Valium Red 2B,
Calcium Red 2B, Lake Red C1 Toluidine Red, Brilliant Carmino 6B, Dioxazine Violet, Naphthol Violet, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Green Gold, Red Garla, Carbon Black, Titanium White, Calcium Carbonate, Barium Sulfate, etc. All of the various dyes and pigments used in the fields of printing and recording can be used. The colorant is preferably used in an amount of 2 to 40 parts by weight per 100 parts by weight of the hot-melt ink.

The thickness of the heat-melting ink layer is preferably in the range of 1 to 5 microns.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples.

Creation of thermal transfer recording medium> Example 1 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricant-retaining TL 1-layer microcrystalline wax (melting point 70℃, penetration rate 9
) was applied to a thickness of 1 μm using a wire bar in a 100° C. constant temperature bath to provide a lubricating protective layer.

・Thermofusible ink layer Paraffin wax (Fm point 72℃) 9 Carnauba wax 3 Carbon black
6 Toluene/Methyl Ethyl Ketone Mixed Solvent 70 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60° C. to form a heat-melting ink layer with a thickness of 3 μm.

Example 2 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer microcrystalline wax (melting point 70℃, penetration level 9)
) was applied to a thickness of 1 μm using a wire bar in a 100° C. constant temperature bath to provide a lubricating protective layer.

・Heat-melting ink layer Paraffin wax (melting point 72°C) 10 Carnauba wax 5 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60°C to a thickness of 3.
A thermofusible ink layer of μ was provided.

Example 3 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer paraffin wax (melting point 68℃, penetration degree 6) 100
The coating was applied to a thickness of 1 μm using a wire bar in a constant temperature bath to provide a lubricating protective layer.

・Heat-melting ink layer Paraffin wax (melting point 72℃) 9 Carnauba Wanks 3 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60°C.
A layer of hot melt ink having a thickness of 3 microns was provided.

Example 4 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer oxidized paraffin wax (melting point 77℃, penetration level 7)
The coating was applied to a thickness of 1 μm using a wire bar in a constant temperature bath at 00° C. to provide a lubricating protective layer.

・Heat-melting ink layer paraffin wax 9 Carnauba wax 3 Aichi Bonplak
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60° C. to form a heat-melting ink layer with a thickness of 3 μm.

Example 5 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer carnauba wax (melting point 82℃, penetration <1) 100
The coating was applied to a thickness of 1 μm using a wire bar in a constant temperature bath at 0.degree. C. to provide a lubrication barrier.

・Thermofusible ink layer Paraffin wax 9 Carnauba wax 3 Carbon blank
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60° C. to form a heat-melting ink layer with a thickness of 3 μm.

Comparative Example 1 The following heat-melting ink layer was formed on a 6μ polyester film to create an ink sheet as a thermal transfer recording medium.

・Thermofusible ink layer Paraffin wax (melting point 72°C) 15 parts by weight Carnauba wax 6 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60° C. to form a heat-melting ink layer with a thickness of 3 μm.

Comparative Example 2 The following heat-melting ink layer was formed on a 6μ polyester film to create an ink sheet as a thermal transfer recording medium.

・Thermofusible ink layer Paraffin wax (melting point 72℃) 9 Carnauba wax 3 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60°C.
A layer of hot melt ink having a thickness of 3 microns was provided.

Comparative Example 3 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer microcrystalline wax (melting point 70℃, penetration level 9)
) was applied to a thickness of 1 μm using a wire bar in a 100° C. constant temperature bath to provide a lubricating protective layer.

・Thermofusible ink layer Paraffin wax (melting point 72°C) 15 parts by weight Carnauba wax 6 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60°C.
A layer of hot melt ink having a thickness of 3 microns was provided.

Comparative Example 4 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer carnauba wax (melting point 82℃, penetration degree 1) 100%
The coating was applied to a thickness of 1 μm using a wire bar in a constant temperature bath to provide a lubricating protective layer.

・Thermofusible ink layer Paraffin wax (melting point 72°C) 15 parts by weight Carnauba wax 6 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 60°C to form a heat-melting ink layer with a thickness of 3 μm.

Comparative Example 5 The following layers were formed on a 6μ polyester film,
An ink sheet, which is a thermal transfer recording medium, was created.

・Lubricating protective layer microcrystalline wax (melting point 70℃, penetration level 9)
) was applied to a thickness of 1 μm using a wire bar in a constant temperature bath at 100° C. to provide one lubrication-retaining layer.

・Thermofusible ink layer Paraffin wax 9 Carnauba wax 3 Carbon black
6 The above composition was kneaded in a ball mill for 12 hours to obtain a coating liquid for forming an ink layer. Next, the above coating liquid was applied using a wire bar and dried at 0° C. to form a heat-melting ink layer having a thickness of 3 μm.

Scratch abrasion fastness test> The ink ribbon (Example 1 to
5. Comparative Examples 1 to 5) were transferred onto thermal transfer paper using a NEC thermal transfer line printer N5234-10, and a clear transferred image was obtained.

In order to evaluate the friction fastness of the obtained transferred image, a scratch strength tester TYPE-11EIDON-1 manufactured by Shinto Kagaku was used.
Using No. 8, the transferred image was scratched with a hemispherical sapphire needle with a tip of 0.1 mm radius, and peeling of the transferred image and staining of the non-transferred area were observed. The test was conducted with two types of loads, 10 g and 20 g, applied to the sapphire needle, and a scratching speed of 10 cm/sec. The test results are summarized in Table-1.

Table 1 Scratch abrasion fastness test results) ○: Peeling of the transferred image and staining of the non-transferred area were not observed.

Δ: Peeling of the transferred image and slight staining on the non-transferred area were observed.

×: Peeling of the transferred image and staining of the non-transferred area were clearly observed.

As is clear from Table 1, the transfer images obtained by the thermal transfer recording medium of the present invention had significantly improved fastness against friction.

Claims (1)

[Claims] A thermal transfer recording medium formed by coating a heat-fusible ink on a base material, which has a lubricating protective layer mainly composed of wax between the base material and the hot-fusible ink, and the heat-fusible ink:
Glass transition point 30~100℃, softening point 40~120℃,
A low crystallinity or amorphous resin having an endothermic amount due to melting of crystals of 10 cal/g or less is used as a heat-melting binder 1.
A thermal transfer recording medium containing 30 parts by weight or more in 00 parts by weight.