JPH0478585A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent the peel of an ink layer under low temp. environment and to carry out printing excellent in friction resistance and transfer properties by providing a release layer based on wax on a support and further providing the ink layer thereon and specifying the ratio of the wax and resin in the release layer and adding a specific amount of a rubbery elastomer to the resin component. CONSTITUTION:A thermal transfer recording medium 1 is formed by providing a release layer 3 based on wax on a support 2 and providing an ink layer 4 thereon and further providing a heat-resistant protective layer 5 to the surface on the side coming into contact with a thermal head of the support 2. The ratio of the wax and resin in the release layer 3 is 95 : 5-80 : 20 and a rubbery elastomer is added to the resin component in an amount of 50-90 wt.%. When the ratio of the resin exceeds 20 wt.%, the bonding strength between the release layer 3 and the support 2 becomes large to generate transfer inferiority. When said ratio is below 5 wt.%, bonding strength becomes low and the peel of the ink layer 4 is generated. When the ratio of the rubbery elastomer in the resin component is below 50 wt.%, the peel of the ink layer 4 is generated and, when said ratio exceeds 90 wt.%, the bonding strength to the support 2 becomes high to generate transfer inferiority.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention particularly relates to a thermal transfer recording medium for barcode printers, and more specifically, the print transfer surface has excellent abrasion resistance, and the ink layer does not peel off when not in use at low temperatures. , relates to a thermal transfer recording medium with excellent storage stability. [Prior Art] In recent years, thermal transfer recording methods using thermal heads have been developed due to their advantages such as being noiseless, making the device relatively inexpensive and compact, being easy to maintain, and producing stable printed images. It has become widely used due to its advantages. Typical examples of thermal transfer recording media used in such thermal transfer recording systems include: (1) those in which a heat-melting ink layer consisting of a colorant and a paint is provided directly on a support; (2) those in which a colorant and a Examples include those in which a heat-melting ink layer consisting of a binder is provided on a support via a release layer mainly composed of wax. However, in the thermal transfer recording medium of type (1) above, the ink layer itself must contain a large amount of pigment such as carbon black in order to obtain an appropriate print density, so the pigment is exposed on the transfer surface after printing. , the receiving paper itself becomes dirty when rubbed with cardboard or a finger, or traced with a pen scanner, etc., making it impossible to read barcodes. On the other hand, the thermal transfer recording medium of type (2) above has a release layer that prevents pigments from being exposed on the transfer surface after printing, and has a much better effect on abrasion resistance than that of type (1) above. show. However, the binder of the ink layer (1) and the binder of the release layer (2) are mainly composed of wax with low plasticity.
The adhesion to resin films such as polyethylene terephthalate (polyethylene terephthalate) is extremely low, resulting in the inconvenience that the ink layer and release layer may peel off from the support due to external mechanical force. This phenomenon is particularly noticeable at low temperatures (5°C to 10°C). However, in order to eliminate this inconvenience, the surface of the support is made uneven to increase the contact area between the ink layer and the support (Japanese Patent Laid-Open No. 58-1.688
No. 9), an intermediate adhesive layer made of cellulose resin, polyester resin, etc. is provided between the support and the ink layer (Special Japanese Patent No. ylJ No. 59-165690, Japanese Unexamined Patent Publication No. 60-54).
894 (publications such as No. 894) have been proposed, however, the manufacturing method and process become complicated, leading to an increase in manufacturing costs. [Problems to be Solved by the Invention] The first object of the present invention is, for example, to ensure that a printed barcode does not fall off or get dirty even if it is rubbed with a finger or cardboard, or that it is readable even if it is repeatedly traced with a pen scanner. An object of the present invention is to provide a thermal transfer recording medium with excellent abrasion resistance. A second object of the present invention is to provide a thermal transfer recording medium that does not peel off ink even in a low temperature environment (5 to 10° C.) while maintaining original print quality and abrasion resistance. [Means for Solving the Problems] According to the present invention, in a thermal transfer recording medium in which a release layer containing wax as a main component is provided on a support, and an ink layer is provided on the support, the wax in the release layer and Resin ratio is 95=
5 to 80:20, and 50 to 90 wt in the resin component
There is provided a thermal transfer recording medium characterized in that g contains a rubber-based elastomer. The present invention will be described in more detail below with reference to the accompanying drawings. FIG. 1 is a sectional view of a thermal transfer recording medium 1 according to the present invention. In this drawing, 2 represents a film-like support, 3 represents a release layer, 4 represents an ink layer, and 5 represents a heat-resistant protective layer. Examples of the support 2 include films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, nylon, and polyimide, as well as glassine paper, condenser paper, metal foil, etc., and the thickness thereof is approximately 2-15 habits preferably 3-10

The range is [. Note that the surface of the support 2 in contact with the thermal head (the surface opposite to the example where the ink layer 4 is present) may be coated with silicone resin, fluororesin, polyimide resin,
By providing a heat-resistant protective layer 5 made of epoxy resin, phenol resin, melamine resin, nitrocellulose, etc., the heat resistance of the support can be improved, or a support material that could not be used conventionally can be used. You can also do it. The peeling layer 3 is mainly made of natural waxes such as carnauba wax, candelilla wax, beeswax, wood wax, montan wax, spermaceti wax, etc., which have a melting point of 40 to 100°C;
paraffin wax, microcrystalline wax,
Synthetic waxes such as oxidized wax and polyethylene wax; Other higher fatty acids such as margaric acid, lauric acid, mystiric acid, valmitic acid, stearic acid, fromenic acid, and behenic acid; Higher alcohols such as stearyl alcohol and behenyl alcohol; Fatty acid esters of sorbitan It is composed of esters such as stearinamide, oleinamide, etc., but wax/resin = 9515-80/
It is necessary to mix the resins so that it becomes 20%. As for the resin, it is desirable that 50 to 90 vt% of the components be comprised of an elastomer such as rubber, and the remaining component should contain an ethylene-vinyl acetate copolymer. Examples of elastomers such as rubber include butadiene rubber, which has excellent adhesive strength stability at low temperatures, and styrene rubber.
Butadiene rubber, nitrile rubber. Nitrile-butadiene rubber, high styrene rubber. There are synthetic rubbers such as isoprene rubber, acrylic rubber, epichlorohydrin rubber, butyl rubber, and ethylene-propylene rubber, and natural rubber. The reason why it is desirable to use ethylene-vinyl acetate copolymer together with elastomer such as rubber as the remaining component is that ethylene-vinyl acetate copolymer has the effect of relaxing the affinity between elastomer such as rubber and wax. This is because the polymer has it. In the absence of ethylene-vinyl acetate copolymer, the wax and rubber and other distomers separate and are heated at low temperatures (5 to 1
(0°C) may not be able to sufficiently achieve the purpose of preventing ink layer peeling. The ratio of wax to resin is preferably 95:5 to 80:20. If the resin ratio exceeds 20% by weight, the adhesive strength between the peeled Jw calendar and 227 will increase, causing the problem of poor transfer. On the other hand, if it is less than 5% by weight, the adhesive strength will be low;
Peeling of the ink layer always causes problems. Furthermore, the ratio of elastomer such as rubber in the resin component is 5.
If it is less than 0 wt %, there will be a problem of ink layer peeling, and if it exceeds 90 wt %, the adhesive strength to PET will be too high, causing a problem of poor transfer. The thickness of the release layer 3 is 0.5 to 10, preferably 1 to 3.
It is a door. If it is thinner than 0.5 degrees, the abrasion resistance will decrease, and if it exceeds 10/7I11, the thermal sensitivity will decrease, resulting in poor image transfer properties, or the ink layer will peel off at low temperatures (5 to 10 degrees Celsius). occurs. The ink layer 4 is composed of a conventionally known heat-fusible layer, and specifically contains colorants, waxes, and resins as main components. The colorant is appropriately selected from conventionally known dyes and pigments. Examples of waxes include paraffin wax, microcrystalline wax, oxidized paraffin wax, candelilla wax, carnauba wax, and montan wax. Ceresin wax, polyethylene wax, oxidized polyethylene wax, castor wax, hardened tallow oil, lanolin, wood wax, sorbitan stearate, sorbitan palmitate, stearyl alcohol, polyamide wax, oleylamide. Waxy materials such as stearylamide, hydroxystearic acid, synthetic ester waxes, and synthetic alloy waxes are accepted. Examples of resins include polyamide-based, polyester-based, polyurethane-based, vinyl chloride-based, cellulose-based, petroleum-based, styrene-based, butyral-based, and phenol-based resins, as well as ethylene-vinyl acetate copolymers and ethylene-acrylic resins. Examples include resin. The ratio of each material constituting the ink layer 4 is colorant/wax/resin=5~50/30~9075~
50 is appropriate. In addition to these, conventionally known plasticizers and oils such as fatty acid esters, glycol esters, phosphoric acid esters, and epoxidized linseed oil may also be added to the ink layer 4 in small amounts (30% or less). The ink layer 4 can be formed by coating as a hot melt or in a dissolved or dispersed state in a solvent and drying, and has a thickness of 1 to 10 pm, preferably 1.5 to 3 pm. [Example] Next, Examples and Comparative Examples will be shown. Parts here are by weight. Example 1 Polyethylene terephthalate (PET) with a thickness of about 4.5 mm
) After drying the coating liquid of component A below on the film, the thickness is about 1
．． It was applied using a wire bar so as to form a five-layer pattern, and dried to form a release layer. (Ingredient A) Carnauba wax 85 parts Toluene 900 parts Furthermore, on top of that, a coating liquid consisting of the following B ingredient was applied to a thickness of about 2I after drying.
The thermal transfer recording medium of the present invention was prepared by applying the ink layer using a wire bar and drying to form an ink layer. (Component B) Carnauba wax Candelilla wax 70 parts 10 parts Isooctane 1150 parts Example 2 A thermal transfer recording medium of the present invention was produced in exactly the same manner as in Example except that the component A was replaced with the component C below. . (Component C) Carnauba wax 75 parts Candelilla wax 10 parts Toluene
900 copies Example 3 A thermal transfer recording medium of the present invention was prepared in exactly the same manner as in Example 1 except that the component A was replaced with the component listed below. (Component D) Carnauba wax 75 parts Toluene 900 parts Comparative Example 1 A comparative thermal transfer recording medium was prepared in the same manner as in Example 1 except that the component A was replaced with the component C below. (Component C) Carnauba wax 85 parts Butadiene rubber 15 parts (Nippon Zeon Co., Ltd.: N1pol BR1220) Toluene
900 copies Comparative Example 2 A comparative thermal transfer recording medium was prepared in the same manner as in Example 1 except that the component A was replaced with the component C below. (Component C) Carnauba wax 85 parts Toluene 900 parts Comparative Example 3 A thermal transfer recording medium was produced in the same manner as in Example 1 except that the above-mentioned component was replaced with the following component C. CG component strength Lunauba wax 65 parts Candelilla wax 10 parts (Nippon Zeon Co., Ltd.: N1pol 1041) 5 parts Ethylene-vinyl acetate copolymer 5 parts (Mitsui DuPont Polychemical Co., Ltd.: EVA FLEX 220)
Toluene 900 parts The Bekk smoothness of these six types of thermal transfer recording media is approximately 4.
, 000 seconds surface-treated mirror coated paper (Kanzaki Paper 1!I), using a thermal transfer printer for barcodes (Autonics: BC-8MK II), 30%
Under the condition of RH15℃, 15.2111J/+1
Printing was performed by applying an energy of 1111", and the transferability, abrasion resistance (cardboard test), abrasion resistance (pen scanner test), and ink releasability were examined. The results are shown in Table 1. The transferability, abrasion resistance (cardboard test), abrasion resistance (pen scanner), and ink releasability were evaluated according to the following 6. Transferability: Evaluation was made based on whether the barcode portion was clearly printed. O: The barcode part is clearly printed and transferred. X: The barcode part is printed unclearly, and there is one barcode that is not partially transferred. The same spot was rubbed 100 times and evaluated. 0...The barcode part is hardly dirty and can be read with a barcode scanner without any problem. ×...The barcode part is quite dirty, Difficult to read with a barcode scanner.Evaluation was made by dividing the number of times n@ and applying it to the formula n150 x 100 (%).10 copies indicates that all can be read.Presence or absence of ink removability: Ink Visually check for layer peeling.
! I guessed it. [Effects] Since the thermal transfer recording medium of the present invention has the above structure, the ink layer does not peel off in a low temperature environment (5 to 10°C).
It also enables printing with excellent abrasion resistance and transferability.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a thermal transfer recording medium according to the present invention. 1: Thermal transfer recording medium 2: Support 3: Release layer 4: Ink layer 5: Heat-resistant protective layer Patent applicant Rico Co., Ltd.

Claims (2)

[Claims] (1) In a thermal transfer recording medium in which a release layer containing wax as a main component is provided on a support, and an ink layer is provided on top of the release layer,
The ratio of wax and resin in the release layer is 95:5 to 80:
20, and 50 to 90 wt% of the resin component contains a rubber-based elastomer. (2) The thermal transfer recording medium according to claim 1, wherein the resin component in the release layer contains an elastomer such as rubber and an ethylene-vinyl acetate copolymer.