JPH03294A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer recording medium hard to generate background staining by containing a specific amount of low MW polybutene-1 and/or a low MW copolymer having a repeating unit derived from butene-1 in the components forming a thermal transfer layer. CONSTITUTION:In a thermal transfer recording medium consisting of a substrate and the thermal transfer layer provided on the substrate, low MW polybutene-1 and/or a low MW copolymer having a repeating unit derived from butene-1 are contained in the components forming the thermal transfer layer in an amount of 1below 15wt.%. Polybutene-1 to be used is low MW one and the intrinsic viscosity of this polymer measured in decalin at 135 deg.C is usually 0.01-0.7dl/g, pref., 0.03-0.5dl/g. The repeating unit derived from butene-1 in the copolymer is contained usually in an amount of 60mol.% or more, pref., 75-100mol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a thermal transfer recording medium in which a thermal transfer layer containing a coloring component and a binder is provided on a substrate.

Technical Background of the Invention With the increasing demand for office automation equipment in recent years, thermal transfer recording devices have come to be widely used as output devices for facsimiles, personal computers, word processors, and the like.

When printing using such a thermal transfer recording device, a thermal transfer recording medium (ink ribbon) in which a thermal transfer layer made of a coloring component and a binder is provided on a substrate is used. The printing method using such a thermal transfer recording device is as follows:
The thermal head is brought into contact with the base side of the thermal transfer recording medium,
By heating the heating points (dots) provided on the thermal head in accordance with the information to be output, the thermal transfer layer is melted or softened in accordance with the heating points, and is separated from the substrate. This is a method of transferring it to the surface of a transfer medium such as paper.

However, with the above method, the thermal head remains heated to some extent even when no printing is performed.
Due to this heat, a portion of the substance with a low melting point or low softening point contained in the heat-sensitive transfer layer is transferred to the surface of the transfer medium that is in contact with the heat-sensitive transfer layer. For example, in addition to binders and pigments, oily components have been added to conventional thermal transfer recording media in order to improve the flexibility and transfer performance of the thermal transfer layer. However, when such an oily component comes into contact with the transfer medium, a portion thereof migrates to the surface of the transfer medium, causing so-called scumming.

In order to prevent such scumming on the transfer medium, for example, Japanese Patent Application Laid-Open No. 59-29196 discloses a medium in which a polyhydroxy resin is blended in the heat-sensitive transfer layer.

This publication states that the adhesion between the thermal transfer layer and the substrate is improved by utilizing the OH group properties of polyhydroxy resin, and that this resin and wax have good affinity. This is prevented by taking advantage of this.

The present inventor has developed a method that is completely different from such conventional methods for preventing background smearing, and by blending a specific amount of a specific polyolefin, even if the heat-sensitive transfer layer contains an oily substance, it can be prevented from being exposed to oily substances. It has been found that migration to the surface of the transfer medium can be effectively prevented.

OBJECTS OF THE INVENTION The present invention is an attempt to solve the problems associated with the prior art as described above, and an object of the present invention is to provide a thermal transfer recording medium that is less likely to cause scumming.

Summary of the Invention A thermal transfer recording medium according to the present invention is a thermal transfer recording medium comprising a substrate and a thermal transfer layer provided on the substrate, in which low molecular weight polybutene-1 is contained in the thermal transfer layer forming components. and/or a low molecular weight copolymer having repeating units derived from butene-1 in an amount of 1% by weight or more 15
It is characterized in that it is contained in an amount within a range of less than % by weight.

As described above, since the thermal transfer recording medium according to the present invention contains a specific amount of low molecular weight polybutene-1 and/or copolymer, it is possible to effectively prevent scumming.

Detailed Description of the Invention Next, the thermal transfer recording medium of the present invention will be specifically described.

The thermal transfer recording medium of the present invention consists of a substrate and a thermal transfer layer provided on the substrate.

Examples of the substrate used in the thermal transfer recording medium of the present invention include polyethylene terephthalate, polyethylene, polycarbonate, polyimide, polyamide,
Resin films made of polyphenylene sulfide, polysulfone, aromatic polyester, polyetheretherketone, polyethersulfone, polyetherimide, and the like can be used.

The thickness of such a resin film is usually 0.8 to 20
It is within the μm range.

A back coat layer may be provided on the surface of such a resin film on which the heat-sensitive transfer layer is not formed, and various layers such as a release layer may be provided on the surface to which the heat-sensitive transfer layer is applied. It's okay.

The thermal transfer recording medium of the present invention has a thermal transfer layer on such a resin film.

This heat-sensitive transfer layer is usually formed from a binder and a coloring component.

Further, this heat-sensitive transfer layer contains a low molecular weight copolymer having repeating units derived from low molecular weight polybutene-1 or polybutene-1.

The polybutene-1 used here is a low molecular weight polybutene-1, and the Jul. The determined limiting viscosity [η] is usually 0.01 to 0.
．． 7dj! /g, preferably 0.03~0°5cN! /
within the range of g.

In the present invention, a copolymer having repeating units derived from butene-1 can be used instead of or together with polybutene-1 as described above.

The copolymer used in the present invention includes butene-
In addition to repeating units derived from 1, copolymers having repeating units derived from α-olefins are usually used.

Here, the repeating unit derived from an α-olefin is preferably a repeating unit derived from an α-olefin having 2 to 10 carbon atoms, and more preferably an α-olefin having 2 to 6 carbon atoms. Particularly preferred are repeating units derived from (with the exception of butene-■).

Such α-olefin may be linear or branched.

Examples of repeating units derived from such α-olefins include ethylene, propylene, pentene-1, hexene-1, heptene-1, octene-1, nonene-11decene-1,3-methyl Pentene-1,4-
Methylpentene-1,5-methylhexene-1 and 6
-Methylhebutene-1 repeating units may be mentioned. Among these, repeating units derived from ethylene, propylene, and 4-methylpentene-1 are particularly preferred.

In such a copolymer, the repeating unit derived from butene-■ is usually contained in an amount of 60 mol% or more, preferably 75 to 100 mol%. Therefore, α
- The repeating units derived from olefins are contained in the copolymer in an amount usually less than 40 mol %, preferably from 0 to 25 mol %.

Incidentally, the above copolymer contains butene-1 and α-1.
In addition to the olefin, it may contain repeating units derived from other monomers within a range that does not impair its properties, for example, in an amount of 30 mol% or less.

The above copolymers are low molecular weight copolymers,
The intrinsic viscosity [η] measured in decalin at 135°C is usually 0.01 to 0.7617 g.

Preferably it is within the range of 0.03 to 0.5 dN/g.

When the above-mentioned copolymers having repeating units derived from polybutene-1 and butene-2 are used together, both can be used in any proportion.

In the thermal transfer recording medium of the present invention: 1. The above-mentioned low molecular weight polybutene-1 is included in the components forming the heat-sensitive transfer layer.
and/or a low molecular weight copolymer having repeating units derived from butene-1, at least 1% by weight and 15% by weight.
preferably 3 to 10% by weight.
It is contained in an amount of

By controlling the amount of polybutene-1 or copolymer to 1% by weight or more, scumming on the surface of the transfer medium can be effectively prevented. Further, even if 15% by weight or more of polybutene-1 or the above-mentioned copolymer is blended, no significant improvement in the prevention of scumming is observed. However, if it exceeds 15% by weight, the printing performance on transfer media with low surface smoothness tends to improve.

The heat-sensitive transfer layer of the heat-sensitive transfer recording medium of the present invention contains a binder and a coloring component in addition to the above-mentioned polybutene-1 or a copolymer having a repeating unit derived from butene-1.

As the binder used in the present invention, a thermoplastic resin or wax, which is generally used as a binder for a heat-sensitive transfer layer, can be used.

As the thermoplastic resin that can be used in the present invention, it is preferable to use a resin having a softening point within the range of 60 to 150"C. Specifically, as such a thermoplastic resin, polyolefin , polyolefin copolymer, vinyl chloride copolymer, vinylidene chloride copolymer, polystyrene, styrene copolymer, coumaron-indene resin, terpene resin, picolite, acrylic resin, polyacrylonitrile, acrylonitrile copolymer, diaseptone acrylamide Polymers, vinyl acetate, vinyl acetate copolymers, polyvinyl ethers, polyamides, polyesters, polyvinyl acetal resins, polyurethane resins, cellulose derivatives, polycarbonates, ionomers, condensates of cyclic ketones and formaldehyde, low xylene or mesitylene and formalin condensate,
Mention may be made of rosin modified products of this condensate and petroleum resins. These resins can be used alone or in combination.

The above thermoplastic resin is included in the components forming the heat-sensitive transfer layer.
Usually 30-90% by weight, preferably 40-70% by weight
It is contained in an amount of

Further, as the wax used in the present invention, it is preferable to use a wax having a melting point of 120°C or less, and examples of such wax include animal waxes such as beeswax and shellac wax, and carnauba wax. Vegetable waxes such as mouth waxes, mineral waxes such as montan wax, petroleum waxes such as paraffin wax and microcrystal wax, polyhydric alcohol esters of higher fatty acids, higher amides, higher amines,
Mention may be made of condensates of fatty acids with aliphatic or aromatic amines and synthetic waxes such as synthetic paraffins and chlorinated paraffins. These waxes are
Can be used alone or in combination.

The above-mentioned wax is usually contained in the components forming the heat-sensitive transfer layer in an amount of 30 to 90% by weight, preferably 40 to 70% by weight.

The heat-sensitive transfer layer further contains a coloring component.

Carbon black is the most widely used coloring component in the present invention, and in addition, red pigments or dyes, yellow dyes or pigments, and blue pigments or dyes may be used alone or in combination. I can do it. In addition, in the present invention, both organic pigments and inorganic pigments can be used as the pigment.

The heat-sensitive transfer layer usually contains the above-mentioned coloring components in an amount of 5% by weight or more, preferably 10 to 40% by weight.

Furthermore, an anti-adhesion agent may be added to the heat-sensitive transfer layer to prevent the heat-sensitive transfer layer of the wound heat-sensitive transfer recording medium from adhering to the back surface of the substrate that comes into contact with the heat-sensitive transfer layer. To ensure good penetration into the transfer medium,
Various oils or high boiling point solvents can also be blended. In addition, additives such as plasticizers, ceramic particles, and stabilizers can also be blended.

A heat-sensitive transfer layer having such a composition can be prepared, for example, by coating with at least a part of the layer-forming components in a molten state (hot-melt method), or by dissolving or dispersing the layer-forming components in a solvent. It can be formed using a known method such as a method of coating with a solvent (solvent method).

For example, when a hot-melt method is adopted to form a thermal transfer layer, the above layer-forming components are mixed, the mixture is heated to a temperature at which the binder is in a molten state, and then this heated mixture is placed on the substrate. The thermal transfer recording medium of the present invention can be manufactured by coating the material and then cutting it into a desired shape.

For example, when a solvent method is adopted, the above-mentioned components forming this layer may be mixed with a solvent such as a ketone solvent such as methyl ethyl ketone, an alicyclic solvent such as cyclohexanone, an aromatic solvent such as toluene, or A coating liquid is prepared by blending the liquid into a mixed solvent, and this coating liquid is applied onto a substrate. Application methods for such coating liquids include gravure coating, reverse roll coating,
Known methods such as air knife coating, dip coating and spinner coating can be used. After applying the coating liquid onto the substrate as described above, by removing at least a portion of the solvent and cutting it into a desired shape,
The thermal transfer recording medium of the present invention can be manufactured.

In this case, the heat-sensitive transfer layer can be formed into a layer by applying coating liquids with different compositions two or more times, or the heat-sensitive transfer layer can be layered on the substrate.
For example, coating liquids containing different coloring components can be applied repeatedly at predetermined intervals.

The thickness of the heat-sensitive transfer layer thus formed is a dry thickness, usually 0.5 to 20 μm, preferably 0.8 to 20 μm.
It is about 10 μm.

The thermal transfer recording medium of the present invention can be used by heating with a thermal head from the substrate side (back side) on which the thermal transfer layer is not provided, similarly to the internal thermal transfer recording medium.

By blending a low molecular weight polybutene-1 and/or a low molecular weight copolymer having a repeating unit derived from butene-1, scumming becomes less likely to occur during printing.

Effects of the Invention The heat-sensitive transfer recording medium according to the present invention includes a low-molecular-weight copolymer having a repeating unit derived from low-molecular-weight polybutene-1 and/or butene-1 in the heat-sensitive transfer layer forming component. Since it is blended in a predetermined amount, it is possible to effectively prevent scumming on the surface of the transfer medium during printing.

Furthermore, by incorporating such a polymer or copolymer, even when using a transfer medium with a low surface smoothness, bleeding will not occur around the printed character (transfer image). It becomes difficult.

EXAMPLES Next, the present invention will be explained in more detail by showing examples of the present invention, but the present invention should not be construed as limited by these examples.

Example 1 Thermal transfer layer forming components having the composition shown below were mixed.

Thermal transfer layer forming component composition Carbon black 20% by weight Carnauba wax 20% by weight Montanic acid wax (manufactured by Hoechst, E) 40% by weight Turpentine oil 10% by weight Low molecular weight polybutene-1 ([η]-〇, 2dg/g) 10% by weight A mixture having the above composition was heated and melted to uniformly disperse carbon black, and then coated on polyethylene terephthalate having a thickness of 9 μm to a thickness of 8 μm, and then coated to a width of 61 mm. It was cut to produce a thermal transfer recording medium.

When the obtained thermal transfer recording medium was set in a thermal printer and printing was performed using high-quality paper as a transfer medium, a clear transferred image without background stains was obtained.

In the present invention, the intrinsic viscosity [η] is a value measured in decalin at 135°C.

Example 2 A thermal transfer recording medium was produced in the same manner as in Example 1, except that the composition of the components forming the thermal transfer layer was changed as shown below.

Thermal transfer layer forming component composition Carbon black 20% by weight Carnauba wax 30% by weight Montanic acid wax (same as above) 40% by weight Low molecular weight polybutene-1 ([η]-0.2dΩ/g) 10% by weight Obtained thermal transfer record When the medium was set in a thermal printer in the same manner as in Example 1 and printing was performed using high-quality paper as the transfer medium, a clear transferred image without background stains was obtained.

Example 3 A thermal transfer recording medium was produced in the same manner as in Example 1, except that the composition of the components forming the thermal transfer layer was changed as shown below.

Thermal transfer layer forming component composition Carbon black 20% by weight Carnauba wax 30% by weight Montanic acid wax (same as above) 40% by weight Turpentine oil
10% by weight low molecular weight polybutenate ethylene copolymer ([η] = 0.3 dfl/g copolymerization molar ratio -90:10) 10% by weight The obtained thermal transfer recording medium was processed in the same manner as in Example 1. When the printer was set in a thermal printer and printed using high-quality paper as the transfer medium, a clear transferred image with no background smear was obtained.

Comparative Example 1 A thermal transfer recording medium was produced in the same manner as in Example 1, except that the composition of the components forming the thermal transfer layer was changed as shown below.

Thermal transfer layer forming component composition Carbon black 20% by weight Carnauba wax 30% by weight Montanic acid wax (same as above) 40% by weight Turpentine oil
The thermal transfer recording medium obtained at 10% by weight was set in a thermal printer in the same manner as in Example 1, and when printing was performed using high-quality paper as the transfer medium, bleeding was observed in the transferred image. Background stains were observed on the transfer medium.

Claims (3)

[Claims] (1) In a thermal transfer recording medium comprising a substrate and a thermal transfer layer provided on the substrate, the thermal transfer layer forming components include low molecular weight polybutene-1 and/or butene-1. 1. A thermal transfer recording medium comprising a low molecular weight copolymer having repeating units in an amount of 1% by weight or more and less than 15% by weight. (2) The intrinsic viscosity [η] of a low molecular weight polybutene-1 and/or a low molecular weight copolymer having a repeating unit derived from butene-1, measured in decalin at 135°C, is 0.01 to 0. 2. The thermal transfer recording medium according to claim 1, wherein the thermal transfer recording medium is within a range of 7 dl/g. (3) The thermal transfer recording medium according to claim 1 or 2, wherein the low molecular weight copolymer contains 60 mol% or more of repeating units derived from polybutene-1.