JPS61244593A - Thermal recording material - Google Patents

Abstract

PURPOSE:To ensure favorable resolution, by using a polyamide resin in place of a conventional binding material comprising a crystalline wax as a main constituent, as a binding material for a thermal recording ink material. CONSTITUTION:In a recording material comprising a heat-fusible thermal recording ink material layer on a base, the ink material comprises a coloring agent, a polyamide resin and an amorphous polyester resin and/or an epoxy resin as main constituents, with the weight ratio of the polyamide resin to the amorphous polyester resin and/or epoxy resin being 90:10-20:80. If the amount of the polyester resin and/or the epoxy resin it too small (10wt% or less), the ink layer is colored in a color peculiar to the polyamide resin, color reproduction of a disperse pigment becomes poor, and when the recording material is used for color recording, transparency of the binding layer becomes poor. On the other hand, if the amount of the polyester resin and/or the epoxy resin is too large (80wt% or more), favorable contribution of the polyamide resin to transfer characteristics is decreased, and dynamic flexibility of the thermal recording material is lowered.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an image recording material that performs thermal transfer by heating the recording material in accordance with an applied signal using means such as a thermal head, laser, or flash light. .

[Conventional technology]

Thermal recording method, which utilizes changes in the physical properties and chemical reactivity of materials in response to the application of thermal energy, was developed in ancient times (
Many methods have been proposed. However, dye coloring reactions between colorless dyes such as crystal violet lactone, fluoran series, and spiropyran series and heptanoyl compounds such as bisphenol A, other organic acids, and inorganic acids, and dye coloring reactions between organic acid metal salts and organic acids such as phenols, etc. A thermosensitive color recording method that utilizes thermal reactions with reducing agents, metal sulfides, organic chelating agents, and organic sulfur compounds, and changes in thermophysical properties such as heat melting and heat sublimation properties to produce ink and color materials on paper, etc. In recent years, thermal transfer recording methods for transferring images onto recording media have been actively researched, and efforts are being made to improve them.

In particular, the latter thermal transfer recording method is highly reliable because it can record on plain paper, the recorded image has good light resistance, stability, and storage stability, and the recording mechanism is simple. Printers, facsimiles,
It is applied to copying machines, etc.

However, in the case of a method in which the dye is thermally sublimated, it has the advantage of being able to reproduce one-degree continuous gradation, but on the other hand, it has problems with recording sensitivity, storage stability of the recording medium, and fixation stability of recorded images. There are problems with properties, light resistance, etc. In addition, in the case of a method in which ink is transferred and recorded by melting the ink in a hot bath, and the ink corresponding to the applied signal is transferred to paper or the like, the above problem is reduced, but usually a crystalline wax with a low melting point is used to form the thermal ink layer. Since it is used as an adhesive, resolution may decrease due to thermal diffusion in the recording medium.
There is a problem that the strength of transferred and fixed images is weak.

Crystalline waxes also have the disadvantage that it is difficult to obtain clear color images due to light scattering of the crystalline phase.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide a heat-sensitive transfer recording material with good resolution.

Another object of the present invention is to provide a thermal transfer recording material with good recording sensitivity, transfer and fixing properties.

A further object of the present invention is to provide a heat-sensitive transfer recording material capable of vivid color reproduction.

[Means and effects for solving the problem] As a result of intensive studies, the present inventors have found that the binder material of the thermal ink material can be made from conventional crystalline waxes or polyamides.
It was confirmed that the object of the present invention could be achieved by changing to fat, and the present invention was completed.

That is, the present invention provides a recording material 1 in which a heat-melting heat-sensitive ink material layer is provided on a support, wherein the heat-sensitive ink material contains a colorant, a polyamide resin, an amorphous polyester resin, and/or an epoxy resin. The heat-sensitive recording material is characterized in that the main components are the polyamide resin and the amorphous polyester resin and/or the epoxy resin in a weight ratio of 90:10 to 20:80.

Conventionally, waxes used as thermal ink materials include paraffin wax, carnauba wax,
Montan wax, honey wax, wood wax, candelilla wax, low-molecular weight polyethylene, α-olefin oligomer, and their copolymers and modified products. Oil, vegetable oil such as tung oil, plasticizers such as dioctyl phthalate and dibutyl 7-thaleate, higher fatty acids such as oleic acid and stearic acid, their metal salts, amides and their topographical conductors are mixed and dispersed with dyes and pigments, etc. It was used as a thermal transfer recording material by coating on a layer of plastic film or capacitor paper.

Waxes, which are conventional binding materials, have a relatively clear melting point in the temperature range from about 50°C to about 150'0 because they are crystalline, and when heated above the melting point, they rapidly change from the solid phase. Changes to liquid phase.

At a temperature about 30υ higher than the melting point, it becomes a low viscosity liquid of about 10 to about 10 poise. On the other hand, amorphous polymers essentially have no melting point and gradually change from the same phase to a liquid phase after passing the glass transition temperature (Tg). The viscosity change during this period basically follows the WLF formula or the Andrade formula, and the viscosity usually decreases to about 10" to 101 ipoise at most even at a temperature about 50°C higher than Tg. In the case of thermal transfer recording, the transfer and fixing sensitivity Since the basic f is controlled by the bath melt viscosity and bath melt viscoelasticity of the binder material, it is obvious from the sensitivity point of view that an amorphous polymer is used as a binder for thermal ink.
)# This is disadvantageous. However, the present inventors have discovered that by using a specific polyamide resin binder material, image quality and image stability can be significantly improved without sacrificing sensitivity. The outline of the heat-sensitive recording material of the present invention will be explained.

The polyamide resin, which is an essential component of the heat-sensitive recording material of the present invention, is made by reacting a linear aliphatic diamine with a dibasic acid such as a so-called dimer acid, which is obtained by converting a fatty acid such as lyluic acid, as a main component. Advantageously, polyamides are used.

From the viewpoint of prevention of blocking and sensitivity of the thermal ink material, it is desirable that the softening point of the polyamide resin be set at about 150 DEG C. or below, preferably about 120 DEG C. or below and about 50 DEG C. or above. These polyamides exhibit extremely good melting properties, with the viscosity decreasing from several poises to several tens of poises at temperatures slightly above the softening point.

In the heat-sensitive recording material of the present invention, an amorphous polyester resin and/or an epoxy resin is used as a non-catalytic component together with the above-mentioned polyamide resin.

The amorphous polyester mentioned here is different from crystalline polyethylene terephthalate, which is conventionally used as a base material for thermal transfer materials, and is basically a substantially amorphous polyester that does not exhibit a clear melting point. .

In the present invention, the composition ratio of the polyamide resin and the amorphous polyester resin and/or epoxy resin is 90:10.
Use in the range of ~20:80.

If the proportion of polyester resin and/or epoxy resin is small (10% by weight or less), the ink layer will exhibit the coloring characteristic of polyamide resin, and the color reproduction of the dispersed pigment will be poor (and coloration may occur). This is not preferable because it deteriorates the transparency of the binding layer.

In addition, if the proportion of polyester resin and/or epoxy resin is high (80% by weight or more), the contribution of the polyamide resin to good transfer properties will decrease, and the mechanical flexibility of the thermosensitive recording material will decrease. I don't like it because it stows away.

In the present invention, in addition to the polyamide resin, amorphous polyester resin, and/or epoxy resin, the following materials may be added as desired. For example, styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, chlorostyrene, vinylbenzoic acid, sodium vinylbenzenesulfonate, aminostyrene and other styrene and its derivatives, homopolymers and copolymers of substituted products, Methyl methacrylate, ethyl methacrylate, butyl methacrylate,
Methacrylic esters such as hydroxyethyl methacrylate, acrylic esters such as methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, α-ethylhexyl acrylate, acrylic acid, dienes such as butadiene, isoprene, acrylonitrile, vinyl ethers, It is possible to use vinyl-based single stitched materials such as maleic acid and maleic acid esters, maleic anhydride, cinnamic acid, vinyl chloride, and vinegar CflH=)Ii alone or in copolymers with other monomers. .

In addition, condensation resins include saturated dibasic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, hexahydrophthalic anhydride, malonic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid, maleic anhydride, and fumaric acid. acid, itaconic acid, unsaturated dibasic acid such as tetrahydrophthalic anhydride, and ethylene glycol, 1,2-propylene glycol: r
-Le, 1. ．． 6-hexanediol, bisphenol A
, bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, and other polyester resins obtained by polycondensation with diols may also be used. In this case, a trifunctional compound such as trimellitic acid, glycerin, or trimethylolpropane may be further used to form a branched or crosslinked polyester. Of course, in the case of the vinyl resin, a polyfunctional monomer such as divinylbenzene may be used in combination with a crosslinked polymer.

Furthermore, polycarbonate, polyurethane, silicone resin, fluorine resin, phenol resin, terpene resin, petroleum resin, hydrogenated petroleum resin, alkyd resin, ketone resin, cellulose derivative, etc. may be used.

When these amorphous polymers or oligomers are used in the form of copolymers, the copolymers may be not only random copolymers, but also alternating copolymers, graft copolymers, and block copolymers depending on the required use. Copolymerization modes such as coalescence and interpenetrating copolymers can be appropriately selected and used. In addition, when using a mixture of two or more types of polymers or oligomers, in addition to mechanical mixing such as melt mixing, solution mixing, or emulsion mixing, co-polymerization,
They may be mixed by a multi-stage polymerization method or the like.

In the heat-sensitive recording material of the present invention, a releasing substance may be further added as a non-volatile binding material component.

The releasing substance added here is the differential scanning thermometry (D
The melting point measured by SC) or the softening point measured by the ring and ball method is 50°C or higher and 200°C or lower, more preferably 60°C.
It refers to an organic substance or an organic/inorganic low molecular weight polymer that is solid at room temperature of C or more and 15011 or less, and has a relatively low surface energy that rapidly becomes a low-activity liquid after exceeding its melting point or softening point. If the melting point/softening point is less than 50°C, it will lack stability during storage and use, and if the melting point is less than 2.
When the temperature is 00° C. or higher, the addition has almost no effect on the thermal energy applied in a normal heat-sensitive recording method.

In the temperature range of about 100 to i80'0, the bath melt viscosity is about 1
0 poise or less, more preferably about 1 poise
Low viscosity and/or critical surface tension that rapidly decreases below e is about 40 dyn/α or less, more preferably about 3
A substance having a low surface energy of 0 dyn/cm or less acts effectively as a releasing substance.

Specifically, higher fatty acids such as palmitic acid and stearic acid, fatty acid metal salts such as zinc stearate, fatty acid esters or partially saponified products thereof, fatty acid derivatives such as fatty acid amides, higher alcohols, and polyhydric alcohols. 4 ester derivatives, paraffin wax, carnauba wax, montan wax, beeswax, wood wax,
Waxes such as candelilla wax, polyolefins such as low molecular weight polyethylene, polypropylene, and polybutylene with a viscosity average molecular weight of about 1,000 to about 10,000, or olefins, α-olefins, maleic anhydride, acrylic acid, Organic acids such as methacrylic acid, low molecular weight copolymers with vinyl acetate etc., low molecular weight oxidized polyolefins, halogenated polyolefins, methacrylic esters with long alkyl side chains such as lauryl methacrylate and stearyl methacrylate, acrylic esters or perfluorinated acrylic esters and methacrylic esters alone or copolymers with vinyl monomers such as styrenes, low molecular weight silicone resins such as polydimethylsiloxane and polydiphenylsiloxane, and silicone-modified organic substances, etc. Cationic surfactants such as ammonium salts and pyridinium salts having long-chain aliphatic groups, anionic surfactants, nonionic surfactants, perfluorinated surfactants, etc. having long-chain aliphatic groups, etc. More than one species can be selected and used.

These mold-releasing substances melt in a bath during heating, and due to their low cohesive force and/or low surface energy effects, they can melt into the heat-sensitive ink material or at the interface between the heat-sensitive ink material and the support. Recording sensitivity and image quality are improved because excessive cohesive force and adhesive force between crystalline polymer molecules and/or at the interface between the amorphous polymer and the support are reduced.

In addition, the heat-sensitive recording material of the present invention includes a charge control and/or prevention agent such as a surfactant, a conductive agent, an antioxidant,
Add thermal conductivity improvers, magnetic materials, ferroelectric materials, preservatives, fragrances, anti-blocking agents, reinforcing fillers, mold release agents, foaming agents, sublimation materials, infrared absorbers, etc. inside or outside of the thermal ink + tn. It may be used by adding it.

However, among all the binder material components, the volume concentration of the resin component is 4.
From the viewpoint of image quality, it is preferable to increase the area so that it occupies 0% or more, especially 70% or more.

As a colorant, black dyes and pigments such as carbon black, oil black, graphite, etc., C, 1, PigmentYe.
Acetoacetate arylamide monoazo yellow pigments (fast yellow series) such as llowl, 3, 74, 97, 98; C, 1, Pigment Yellow 1
Acetoacetate arylamide disazo yellow pigments such as 2, 13, 14 etc. e, c, I', 5olvent
Yel low 19, 77, 79, C, 1, Dl
Yellow dye such as sparse Yellow 164; C,
1, PIgment Red 48, 49:1, 5
3:1, 57:1. Red or pink pigments such as 81, 122, 5 etc.: C,1,5olvent Red 5
2. Red dyes such as 58 and 8: C, 1, Pigme
Fruit and vegetable dyes and pigments such as copper phthalocyanine and its derivatives and modified products such as nt Blue 15:3, as well as dyes and pigments well known for conventional printing inks and other coloring applications, such as colored or colorless sublimable dyes, can be used.

These dyes and pigments may be used alone or in combination of two or more. Of course, the color tone may be adjusted by mixing with an extender pigment or a white pigment. Furthermore, in order to improve the dispersibility of the binder component, the surface of the colorant may be treated with a surfactant, a coupling agent such as a silane coupling agent, or a polymeric material, or a polymeric dye or a polymeric duraft pigment may be added to the surface of the colorant. May be used.

In the heat-sensitive recording material of the present invention, a heat-sensitive ink material prepared by mixing polyamide, amorphous polyester, and/or epoxy resin, a colorant, a desired release material, and the various additives mentioned above is placed on a support. It is formed by

The thermal ink materials can be mixed with a bath liquid and/or a dispersion emulsion in a solvent and/or dispersion medium in which the binder material is dissolved and/or stably dispersed, by ball milling, ball milling, etc.
It can be prepared using a mixing and dispersing machine such as a sand mill, attritor, or three-roll mill.

Father, without using any solvent etc., heating type 3 0-l,
Pressure j% pressure kneader, Bamba! Melt mixing may be performed using a J-mixer or the like.

Furthermore, a heat-sensitive ink material may be prepared by polymerizing an amorphous polymer or oligomer as the main binding material in the presence of a colorant, additives, etc.

The heat-sensitive ink material prepared in this way is coated on the support.
Coating and printing is performed using a gravure coater, a wire, etc. using a solution and/or bath melt coating method.

Alternatively, the thermal ink material may be pulverized by a spray drying method, a pulverization method, etc., and then powder coated onto a support by an electrostatic coating method or the like. In this case, it is necessary for the page after powder coating (
Accordingly, heat, pressure, solvent treatment, etc. may be performed to fix the heat-sensitive powder ink on the support.

Convenient supports include polyesters such as polyethylene terephthalate, polyimides and imide copolymers, fluorine polymers, plastic films such as polypropylene, thin sheets and films such as capacitor paper (
used. These sheets, films, or rolls are used with the addition of thermal property modifiers, mold release agents, antistatic agents, conductive agents, and reinforcing agents to improve their internal thermal conductivity, thermal stability, etc. It's okay. In addition, when recording is performed using a thermal head or the like, silicone-based, fluorine-based compounds, a resin layer, a crosslinked polymer layer, A metal layer, a ceramic layer, etc. may also be provided.

Furthermore, the film internal additive may be added to the outer layer. Even if the surface of these supports is smooth or uneven,
Grooves or the like may be provided, or the material may be porous.

Alternatively, an electrothermal conversion element or a photothermal conversion element having a structure similar to that of a thermal head may be directly used as the support, and a thermal ink layer may be provided thereon.

The thickness of the support film or sheet and the thickness of the heat-sensitive ink layer may be appropriately selected depending on the application, but in general, a support thickness of about 1 μm to 7 Hz to about 200 μm is easily used. To increase resolution, the force is approximately 1 μm) and approximately 10
A value of approximately μm is preferred. The thermal ink layer is about 0.5 μm, up to about 50 μm depending on the application, and usually about 1 μm.
It is easy to use if it is set within a range of approximately 20 μm from m. An intermediate layer for controlling adhesion may be disposed between the thermal ink layer and the support, or the thermal ink layer itself may be a multilayer coating layer of multiple types of thermal ink materials with different physical properties, or multiple types of thermal ink materials with different physical properties may be coated within a plane. The ink material may be divided and coated.

The heat-sensitive recording material formed in this way is heated in accordance with the applied signal by means such as a thermal head, laser, flash light, or direct electrical signal, and is brought into contact with a recording medium such as paper or film. The heat-sensitive ink material is transferred and recorded by being ejected in a non-contact state or in a non-contact state. In order to improve recording performance (in addition to mechanical forces such as pressurization and foaming, it is also possible to use electric fields, magnetic fields, ultrasonic waves, bath agents, etc.) in combination.

〔Effect of the invention〕

The polyamide resin obtained from the reaction of dimer acid and aliphatic diamine used in the present invention has an aliphatic main chain in the molecule, so it has an a-like quality that is closer to wax than ordinary polymers. The paper transferability is good. When this polyamide tree +11 is combined with an amorphous polyester resin and/or an epoxy resin, the polyester becomes -CO
Since epoxy has functional groups such as OH and -OH, and epoxy has glycidyl functional groups, they interact (such as hydrogen bonds) with the amide bonds present in polyamide resin, resulting in extremely
It has good dispersibility, good mechanical flexability and strength.When used as a binder resin for the ink layer of an ink donor film (IDF), blocking ζ However, when 10,000 energy is applied, the functional group interaction disappears and the good transfer properties of the original polyamide resin are maintained. The heat-sensitive recording material of the present invention exhibits good transferability and good properties for printing and ink layers, which were contradictory properties in conventional heat-sensitive recording materials. It has the characteristics of both mechanical strength and protskindness.

Also, since polyamide is usually colored,
Although it is considered unsuitable for use in color recording, this problem can be solved by rubbing a mixed system with epoxy resin and amorphous polyester, which have good transparency. You can also use it.

〔Example〕

The present invention will be explained below with reference to examples, but the present invention is of course not limited to these examples. In addition, in the following examples, the part represents a heavy European part unless at is specified.

Example 1 A thermal ink material having the following composition was mixed and dispersed using an attritor=l trowel.

The heat-sensitive ink material obtained above was applied onto a polyester film with a thickness of 6 μm, and the coating weight after drying was 3.5 μm.
f/n? It was coated by gravure coating to give a heat-sensitive recording material.

This is a thick film type thermal head (heating element density = 8.1・
・When printed using a thermal transfer printer equipped with a heating element average resistance value of 3500, the letters were very clear and the contours of the letters were very clear. A print was obtained. Even if the transferred image was rubbed vigorously, no peeling of the ink or smudging of the characters occurred.
It was very strong.

Example 2 A heat-sensitive ink material having the following composition was prepared in the same manner as in Example 1, and a heat-sensitive recording material was prepared.The heat-sensitive recording material was evaluated in the same manner as in Example 1, and it was found to be extremely clear and strong. A good print was obtained.

Claims (1)

[Claims] In a recording material in which a heat-melting thermal ink material layer is provided on a support, the thermal ink material mainly contains a colorant, a polyamide resin, an amorphous polyester resin and/or an epoxy resin, and the polyamide resin and a A heat-sensitive recording material characterized in that the composition ratio of crystalline polyester resin and/or epoxy resin is in the range of 90:10 to 20:80 by weight.