JPS6213384A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer recording material capable of clear color reproduction and having excellent resolution, recording sensitivity, transfer properties and fixing properties, by providing a thermal recording ink material comprising a specified noncrystalline polyester resin and a coloring agent as main constituents. CONSTITUTION:A noncrystalline polyester resin having a polystyrene-basis number average molecular weight measured by gel permeation chromatography of not more than about 10,000 and a glass transition temperature (Tg) measured by differential scanning calorimetry of not lower than about 40 deg.C, preferably, an average molecular weight of not more than about 5,000 and a Tg of about 50-80 deg.C is used as a binder material in a thermal recording material. The noncrystalline polyester resin may be, for example, one which is obtained by polycondensation of a saturated dibasic acid, e.g., phthalic acid or phthalic anhydride, an unsaturated dibasic acid, e.g., maleic anhydride or fumaric acid, or a dimer acid obtained by dimerization of linoleic acid, with ethylene glycol, 1,2-propylene glycol or the like.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to heating a recording material in response to an applied signal using a thermal head, a laser, a flash light, or a direct electric signal. This invention relates to a face recording material characterized by thermal transfer.

[Conventional technology]

Many thermal recording methods have been proposed for a long time that utilize changes in the physical properties and chemical reactivity of materials in response to the application of thermal energy. Among these, dye coloring reactions between colorless dyes such as crystal violet lactone, fluoran series, and spiropyran series and phenolic compounds such as bisphenol A, other organic acids, and inorganic acids, organic acid metal salts and organic reducing agents such as phenols, and metals. A thermosensitive color recording method that utilizes thermal reactions with sulfides, organic chelating agents, and organic sulfur monomer compounds, as well as changes in thermophysical properties such as heat melting and heat sublimation properties, allows inks and coloring materials to be printed on paper, etc. The thermal transfer recording method for transferring information onto a recording medium has been actively researched in recent years, and efforts have been made to improve it. In particular, the latter thermal transfer recording method has the ability to record on plain paper, the light resistance and stability of recorded images, and
Since it has advantages such as good storage stability, simple recording mechanism, and high reliability, it is applied to printers, facsimile machines, copying machines, etc. however,
In the case of the method of thermally sublimating the dye, it has the advantage of being able to reproduce continuous gradation of density, but on the other hand, there are problems with recording sensitivity, storage stability of the recording medium, fixing stability of recorded images, light fastness, etc. be. In addition, in the case of a method of transferring and recording ink corresponding to an applied signal to paper by thermally melting the ink metal, the above-mentioned dropout can be reduced; Since it is used as a binder, it has problems such as a decrease in resolution due to thermal diffusion in the recording medium and weak strength of transferred and fixed images. Furthermore, crystalline waxes have the disadvantage that it is difficult to obtain clear images due to light scattering of the crystalline phase.

In other words, in order to obtain a clear color image, especially a complete Victorian full color reproduction image, by repeatedly recording ink materials several times, magenta, yellow, and cyan ink materials are usually used. By superimposing them, secondary colors and even tertiary colors are obtained. For example, when a secondary color is obtained by superimposing two types of ink materials, the pigments of the actually obtained secondary color and the intended secondary color are determined by the transparency of the ink materials. When performing overlapping recording,
At least the transparency of the ink material superimposed on the upper layer, more precisely the transparency of the ink material binding layer, is good.
The reflected light from the overlapping ink layers becomes closer to the secondary color reflected light due to the characteristics of the pigment itself, and the color reproducibility is improved accordingly.

Conventionally, examples of using resin as a binding component of a heat-sensitive ink layer include JP-A-54-87234 and JP-A-56-9826.
No. 9, etc. are known, but all of these are for the purpose of improving the regularity and durability of printing for thermal ink materials that use wax as a binder, and are used for binding for color old cash purposes. No technical disclosure has been made regarding the transparency of the ingredients.

[Problem that the invention seeks to solve]

Therefore, it is an object of the invention to provide a complete thermal transfer recording material that enables clear color reproduction.

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

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

[Means and effects for solving the problem] As a result of intensive studies, the present inventors have found that the binder for thermal ink materials has changed from the conventional one mainly composed of crystalline waxes to a substantially amorphous one. It was discovered that the object of the present invention could be achieved by changing to polyester, and the present invention was completed.

That is, the present invention provides a recording material in which a heat-melting heat-sensitive ink material layer is provided on a support, wherein the heat-sensitive ink material comprises an amorphous polyester resin with a glass transition temperature of 40° C. or higher and a number average molecular weight of 11QOOO or lower, and a colorant. This is a heat-sensitive recording material characterized by being a material containing as a main component.

The amorphous polyester used in the present invention is a polyester that basically does not exhibit a clear melting point, unlike crystalline polyesters (such as polyethylene terephthalate) conventionally used as base materials for thermal transfer materials.

Conventionally, waxes used as binding materials for thermal ink materials include paraffin wax, carnauba wax,
Montan wax, beeswax, wood wax, candelilla wax, low molecular weight polyethylene, α-olefin oligomer d
If necessary, mineral oil such as spindle oil, vegetable oil such as linseed oil and tung oil, plasticizers such as dioctyl phthalate and dibutyl phthalate, olefinic acid, and stearin. Thermal transfer recording materials were made by mixing and dispersing higher fatty acids such as acids, their metal salts, amides, and other derivatives together with dyes and pigments, and coating them on a thin layer of plastic film or capacitor paper.

Waxes, which are conventional binding materials, have a relatively clear melting point in the temperature range of about 50°C to about 150°C because they are crystalline, and when heated above the melting point, they rapidly change from a solid phase to a liquid. change into phases. At a temperature about 30° C. higher than the melting point, it becomes a low viscosity liquid with a viscosity of about 10 to about 10 poisθ. On the other hand, in the case of amorphous polymers, there is essentially no melting point, and the phase gradually changes from the same phase to the liquid phase at the glass transition temperature (Tg'l'i).The viscosity change during this time is WLF Basically according to the formula or the Ant9rade formula,
Even at a temperature about 50℃ higher than Tg, it is at most 10 to 10po
The viscosity usually decreases only up to about isθ. In the case of thermal transfer recording, the transfer and fixing sensitivity is basically controlled by the melt viscosity and melt viscoelasticity of the binder material. This is clearly a disadvantage.

However, the inventors have found that using an amorphous polyester with a specific molecular weight and Tg as a binding material significantly improves image quality and image stability without sacrificing sensitivity. .

The heat-sensitive recording material of the present invention will be explained in detail below.

The heat-sensitive recording material of the present invention has a polystyrene equivalent number average molecular weight of about IQOOOO or less and a differential scanning calorific value (D
Glass transition temperature (Tg) measured by SG) method is approximately 40℃
More preferably, an amorphous polyester having a number average molecular weight of about 5,000 or less and a Tg in the range of about 50°C to 80°C is used as the binding material.

When Tg is less than 50°C, particularly less than 40°C, blocking of the thermal ink material is likely to occur, resulting in lack of stability during storage and use. If Tg exceeds 80° C., the thermal stability may be poor or the sensitivity may be low, so that it is impractical and cannot be used except for special purposes.

It has been experimentally confirmed that even if the Tg is within the above range, the sensitivity decreases when the molecular weight of the amorphous polyester is high. This is presumed to be due to the cohesive force between molecules based on the entanglement of molecules, etc., and the number average molecular weight is about 10,000 or less,
In particular, good transfer and fixing properties were obtained when the toner was s, ooo or less. The setting of the weight average molecular weight may vary depending on the use of the thermal transfer recording material. Similar to conventional wax-based inks, when it is desired to obtain a single binary transfer image, the weight average molecular weight is set to about 40,000 or less, more preferably about 10,000 or less, and by narrowing the molecular weight distribution, amorphous [ It would be unpleasant to make the softening properties of J Lyester more sensitive. On the other hand, if you want to obtain density gradation or multilevel transfer images, or if you want to use it repeatedly many times, it is desirable to transfer an amorphous polyester that exhibits gradual softening characteristics by melting according to the applied energy. For this purpose, the weight average molecular weight does not necessarily need to be made small, and may be set to about 40,000 or more. Of course, even in this case, a binary transfer image can also be obtained satisfactorily. Furthermore, the shape of the molecular weight distribution does not necessarily have to be a shape having a single molecular weight peak, but may be a distribution shape having a plurality of molecular single peaks, or a crosslinked or branched polymer component may be used in combination. .

The present invention ((amorphous Z IJ ester resins used include phthalic acid, phthalic anhydride, inphthalic acid, terephthalic acid, hexahibirophthalic anhydride, malonic acid, succinic acid,
Saturated dibasic acids such as glutaric acid, adipic acid, and sebacic acid, unsaturated dibasic acids such as hydrated maleic acid, fumaric acid, itaconic acid, and tetrahydro L1 hydrophthalic acid, or dimer acids obtained by duplicating the liluin version. Ethylene glycol, L2-propylene glycol, L6-hegysandiol, bisphenol compounds represented by the following formula j Amorphous yg +) ester resin, etc. In this case, a trifunctional compound such as trimellitic acid, glycerin, or trimethylolpropane may be further used to form a branched or crosslinked polyester. Among them, aromatic polyesters containing bisphenol components in the main chain skeleton have a number average molecular weight of '1lQ ('10
When the glass transition temperature is limited to 0 or less, the glass transition temperature can be suitably controlled within the above temperature range, so it can be used very conveniently as the binder material of the present invention. Although the acid value and hydroxyl value are not particularly specified, values of about 60 or less are usually easy to use.

Polyester usually has -COOH groups and - at the molecular chain ends.
It has an H group. Utilizing these functional groups, modified polyesters and polyesters may be used as binding materials in the form of tr-containing block copolymers or graft copolymers through condensation reactions, ionic reactions, polymer reactions, and the like. In the case of unsaturated polyester, it may be used as a binding material in the form of modified polyester or gold-containing graft copolymer by utilizing the double bond gold in the molecule.

For example, silicone compounds modified by reacting the terminal 1COOH or 10H groups with fatty acids or higher alcohols such as stearic acid or stearyl alcohol, or modified by reacting with incyanates or amines. Modification by reaction with epoxies, phenols, etc. is also possible. In addition, it can be further condensed with a mainly crystalline aliphatic polyester to form a block copolyester, or it can be used to form block copolyesters, such as styrenes such as styrene and α-methylstyrene, and methyl A graft copolymer containing polyester can be obtained by polymerizing one or more types of vinyl polymerizable monomers such as methacrylic esters such as methacrylate and butyl acrylate, and acrylic esters. Alternatively, zinc acetate, zinc oxide, etc. can be added to form an ionic crosslink with the terminal carboxylic acid.

The binder material of the present invention can sufficiently achieve its purpose even if it is composed only of the above-mentioned polyester ground fat of -Mm or less, but if necessary, it can also be made of polyester resin or additives. agent,
They may be added and mixed.

Examples, t ili', styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, chlorstyrene,
Homopolymers and copolymers of vinyl benzoic acid, vinyl (sodium sulfonate, styrene such as aminostyrene, derivatives thereof, and substituted products); methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate; Methacrylic acid, methyl acrylate, ethyl acrylate,
Acrylic acid esters and acrylic acid such as butyl acrylate, 2-ethylhexyl acrylate, butadiene,
Dienes such as isoprene, acrylonitrile, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl monomers such as vinyl chloride, vinyl acetate, etc. alone or in combination with other monomers. Polymers can be used. Of course, the vinyl resin may also be used as a crosslinked polymer using a polyfunctional monomer such as divinylinzene. In addition, using polycarbonate, hollyamide, epoxy M&S urethane, silicone thread resin, fluorine resin, phenol resin, terpene resin, petroleum resin, hydrogenated petroleum resin, alkyd resin, ketone resin, cellulose fermentation conductor, etc. When these polymers or oligomers are used in the form of a copolymer, the copolymer may be a random copolymer, an alternating copolymer, a graft copolymer, or a block copolymer depending on the desired use. A copolymerization mode such as a copolymer or an interpenetrating copolymer can be appropriately selected and used.In addition, when using a mixture of two or more types of polymers or oligomers, melt mixing,
In addition to mechanical mixing such as solution mixing and emulsion mixing, coexistence polymerization, multistage polymerization, etc. may be used when polymer and oligomer components are polymerized.

Further, if necessary, waxes, oils, and liquid plasticizers such as those used in conventional heat-sensitive ink materials may be added and mixed. In addition, olefin homopolymers or copolymers such as ethylene and propylene, organic acid-grafted olefin copolymers, chlorinated paraffins, low-molecular urethane compounds, plasticizers that are solid at room temperature, surfactants, etc. are charged. Control and/or inhibitor, conductive agent, antioxidant, thermal conductivity improver, magnetic material, ferroelectric material, preservative, fragrance, anti-blocking agent, reinforcing filler, mold release agent, foaming agent, sublimation Substances, infrared absorbers, etc. may be added to the inside or outside of the heat-sensitive ink material. However, among all the binding material components,
In terms of image quality, it is preferable that the amorphous d IJ ester component occupies a volume concentration of 50 or more, particularly preferably 70 or more.

Colorants include carbon black, oil black,
Black dye and pigment such as graphite; C, I PigmθΩtY
θ11ow! , same 3. Same 74. 97. C, 1, Pigment Yellow
12. Acetoacetic acid arylamides 9 such as 13 and 14
Disazo yellow pigment; C,1,5o1vsnt Yel
low 19. 77, 79. C,1,Dispe
Yellow dye such as rse YellowW 1 fi4; C,
1, Pigrt+emt Red 48. 49:1
, 53:], 57:1, 8], 122. Red or red pigment of the same grade; C, 1,5olVent
R,,,d, 52゜1ml 58, Red dyes such as 8; C, 1, Pigment Blue 15:3 Blue dyes and pigments such as copper phthalocyanine and its derivatives and modified products, and colored or colorless sublimation Conventionally known dyes and pigments for printing inks and other coloring applications, such as color dyes, can be used.

These dyes and pigments may be used alone or in combination of two or more. Of course, it may be mixed with an extender pigment or a white pigment to completely adjust the color tone. Furthermore, in order to improve the dispersibility of the binder component, the surface of the colorant is treated with a surfactant, a coupling agent such as a silane coupling agent, or a polymer material, or a polymer dye or a polymer graft pigment is used. It's okay.

The heat-sensitive transfer recording material of the present invention is formed by placing a heat-sensitive ink material mixed with an amorphous polyester, a colorant, and, if necessary, the various additives described above, on a support.

The heat-sensitive ink materials are mixed into a solution tQ and/or a dispersed emulsion in a solvent and/or dispersion medium that can dissolve and/or stably disperse the binder material, using a ball mill, Zambi mill, attritor, three-roll mill, etc. With a mixing/dispersing machine? #A can be made. Alternatively, the mixture may be melt-mixed using a heated triple roll, heated and pressurized Negoo mixer, Banbury mixer, etc., without using any solvent or the like.

Furthermore, an amorphous jelly ester, which is the main binding agent, may be synthesized in the presence of a coloring agent, a cooling agent, etc., and used as a heat-sensitive ink material. The heat-sensitive ink material prepared in this way is coated on a support by a solution and/or emotional coating method using a gravure coater, a wire bar, etc.
1l is given.

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, the heat-sensitive powder ink may be fixed on the support by heating, pressurizing, solvent treatment, etc. as necessary after powder coating.

As a support (d% polyester such as polyethylene terephthalate, 71 soliimide and imide 3-based copolymer,
Plastic films such as fluoropolymer and polypropylene, thin sheets and films such as capacitor paper are conveniently used. These sheets, films, or rolls contain thermal property modifiers, mold release agents, antistatic agents, conductive agents, and reinforcing agents to improve thermal conductivity, thermal stability, etc. It may also be used as In addition, when recording is performed using a thermal head 4 or the like, silicone-based,
Fluorine compounds, resin layers, cross-linked polymer layers, metal layers,
A ceramic layer or the like may also be provided.

Furthermore, the film internal additive may be added to the outer layer. The surface of these supports may be smooth, or may have ridges, irregularities, grooves, etc., or may be porous. or,
A structure similar to a thermal head as a support? Alternatively, the electrothermal conversion element may be used directly, and a heat-sensitive 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 with a thickness of about 1 μm to about 200 μm is easy to use. In order to improve the resolution, the thickness is preferably about 1 μm to about 10 μm. The thermal ink layer has a thickness of about 0.5 μm, up to about 50 μm depending on the application, and usually about 1 μm to about 2 μm.
It is easy to use if it is set in the range of about 0 μm. An intermediate layer for controlling adhesion may be disposed between the thermal ink layer and the support, or the electrothermal ink layer itself may be a multilayer boat layer made of multiple types of thermal ink materials with different physical properties, or a plurality of layers W with physical properties may be arranged in a plane. The seed ink material may be completely coated separately.

The heat-sensitive recording material formed in this way is heated in response to the applied signal by means such as a thermal head, laser, flash light, or direct electric signal application, and is then heated to a recording medium such as paper or film. The heat-sensitive ink material is transferred and recorded by flying in contact with or in a non-contact state. In order to completely improve recording properties, it is also possible to use not only mechanical forces such as pressurization and foaming, but also electric fields, magnetic fields, ultrasonic waves, solvents, etc.

〔Example〕

The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is of course not limited to these Examples. In the following examples, parts represent parts by weight unless otherwise specified.

Comparative Example 1 A thermal ink material having the following composition was melt-mixed at 100° C. and then kneaded using a three-roll mill.

Colorant for Nijian ink: C, T, Pigmen
t Blue 15: 3 For magenta ink: C,
T, Pigment Red 57: 1 for yellow ink: G, 1. PiFP8nt Yellow 1
2 Heat the three color thermal ink materials obtained above at 110'C.
The thermal ink layer thickness is ′;L5μ on a polyimide film with a thickness of 7.5 μm placed on a hot plate heated by K.
It was coated with a wire bar to give a heat-sensitive recording material.

Comparative Example 2 Same coloring agent as Comparative Example 1? Three color thermal ink materials of cyan, magenta and yellow having the following compositions were mixed in a ball mill at room temperature for 40 hours to prepare them.

The three-color thermal ink material obtained above was coated with a thickness of 7.5 μm.
The heat-sensitive ink was coated onto the Horiimito 9 film using a wire bar so that the thickness of the heat-sensitive ink layer after drying was 2.5 μm to obtain a heat-sensitive recording material.

Example 1 Using the same colorant as in Comparative Example 1, thermal ink materials in three colors of cyan, magenta, and yellow having the following compositions were prepared by mixing in a gold ball mill at room temperature for 40 hours.

The three color thermal ink materials obtained above were coated on a 7.5 μm thick polyimide film using a wire bar in the same manner as in Comparative Example 2 so that the dry thermal ink layer 4 would be 2.5 μm. It was used as a heat-sensitive recording material.

The table below shows the results of a comparative evaluation of typical recording properties of these thermal recording materials using a Fuji Xerox IIFXP-6 thermal transfer printer.

The method for evaluating recording characteristics is as follows.

Recording sensitivity: Thermal head heating element size (radiation = 12
The thermal snake applied energy (E) required to record a transferred dot corresponding to 5 μWL) ○; E (0,9zJ/aot Δ; 0.9 mJ/dot
o tX; 1.2 mJ/lot <E Resolution: legibility of kanji (especially those with a large number of strokes), fixation level, ink peeling when rubbed with two fingers or an eraser, and smearing of letters 1j and H after transfer. Transparency: Two-visual comparison of color turbidity and gloss when transferred and recorded on an OHP sheet and projected onto a screen. Comparison: Visually compare the color transferred and recorded on an OHP sheet with the Munsell standard color chart in a complete visual comparison table. A supplementary explanation will be given below regarding the evaluation results of each of the heat-sensitive recording materials shown.

Comparative Example 1 using wax as a binder is Example 1 for each color.
It is possible to record with an applied energy of about 80 mm, and has slightly better recording sensitivity, but in the case of kanji characters with a large number of strokes, characters may be blurred and difficult to read, and if you rub the transferred image with your finger, the transferred image may be distorted. stains formed around the area. On the other hand, in Example 1, the recording sensitivity was almost the same as that of the wax type (Comparative Example 1), and clear prints without crushing or blurring were obtained, and even if the transferred image was rubbed strongly, the ink did not peel off or stain at all, making it an excellent product. It showed excellent recording characteristics. Furthermore, in terms of transparency, the wax mold was dark in all three colors, and only a dull colored projected image was obtained, whereas a bright colored projected image without turbidity was obtained. This difference is most noticeable in yellow ink and lily, and when we experimentally measured the diffused light transmittance, it was found that the wax type was 10.5% at a wavelength of 700 nm, where there is almost no pigment absorption.
On the other hand, in Example 1, there was only Z34, and it was confirmed that there was very little diffused light and the transparency was good. In addition, in Example 1, the transferred image obtained from the wax type had all the glittery surface gloss characteristic of wax, whereas a transferred image with uniform and smooth surface gloss was obtained. In terms of color mixing properties, Example 1 has superior properties such as transparency that are closer to the characteristics of process ink in printing than the wax type, so the wax type can only produce secondary colors that are strongly influenced by the overlay of the color mixing order. However, more vivid secondary colors of red, green, and blue were obtained. I tried comparing each transferred image with the Munsell standard color chart and found that it was cyan and magenta.

Regarding the primary color of yellow, the wax type and Example 1 had almost the same hue and brightness, but in terms of saturation, Example 1
was clearly superior, and results similar to those of the grinding wheel were confirmed for the secondary colors, although there was a slight shift in hue.

In addition, in Comparative Example 2, the results were similar to those of Fujigen in terms of fixation, transparency, gloss, and color mixing properties of the transferred image, but the recording sensitivity was inferior to the wax type, and details such as dots of kanji characters were lost. There were also problems with resolution, such as missing images.

Example 2 A heat-sensitive recording material made of black ink was prepared in the same manner as in Example 1 using carbon black as the first agent, and an evaluation fdNr was performed. As a result, the energy applied to the thermal head 9 (E') was about 1.3 times that of the wax type. :=0.8 mJ/dot), clear prints with sufficient fixing strength and without collapse or blur were obtained.

Example 3 However, fruit and vegetable dye (C, 1,5olvent) was used as a coloring agent.
Blue180), red dye (C,1,5olvent
Red Pi 2 )% yellow dye (C,1,5o1v
Example 1 using ent Yellow 77)'c
Similarly, cyan ink, magenta ink, and yellow ink were prepared and heat-sensitive recording materials were made and evaluated. As a result, strong printing with excellent transparency and color mixing properties was achieved without crushing or blurring. It was done.

Example 4 The following set of thermal ink materials having ff1Th were prepared by mixing and dispersing them in an attritor.

The heat-sensitive ink material obtained above was 7.5 μm thick.
Thermal ink layer thickness after drying on IJ Imitriilm is 3
It was coated with gravure coating to give a thickness of 5 μm, and was used as a heat-sensitive recording material.

When this was printed using a thermal transfer printer equipped with a thermal head with a heating element density of 8 dots/w (heating element average resistance value - 3500), the energy applied to the thermal head varied from 0.5 yaJ/aot to 1.5 yaJ/aot. A transferred image was obtained in which the printing density changed continuously from 0.01 to 1.40 at an axis rotation of 2 mJ/dot, and the gradation reproducibility was excellent.

Implementation 115 Thermal ink materials L2 having the compositions shown below were mixed and dispersed using an attritor to create each.

Thermal ink material 1 Thermal ink material 2 Thermal ink material 2 and thermal ink were laminated so that the thermal ink material 2 and the thermal ink were laminated on the 75 μm thick polyimide film obtained above so that the thermal ink film thickness after drying was 2 μm each. Materials were coated in the order of material 1 using gravure coating to obtain a heat-sensitive recording material.

When this was printed using the same thermal transfer printer as in Example 4, a 3-value digital print density that could stably record a print density of about half the saturation density (0, 0 = 1.4) was found. It was confirmed that it has the following characteristics.

〔Effect of the invention〕

The heat-sensitive recording material of the present invention is excellent in recording sensitivity, transferability, fixing performance, resolution, and color reproducibility of images on a transfer material.

The amorphous polyester resin used in the present invention usually has -C(3)H groups and 10H groups at the molecular chain terminals, but these functional groups are present on the support supporting the thermal ink material or on the transfer. Hydrogen bonding occurs on the material, which greatly contributes to the film formability of the thermal ink material on the support, and contributes to good transferability on the transfer material. Furthermore, it exhibits sufficient fixing properties compared to conventional products using low melting point crystalline waxes.

The amorphous polymer used in the present invention is different from the crystalline wax which is a binder used in conventional heat-sensitive recording materials. The binding layer of the heat-sensitive recording material of the present invention exhibits extremely good transparency because the light scattering that previously occurred can be completely eliminated or controlled to a level that does not cause any problems.

In particular, for the purpose of obtaining clear color images, especially Victorian full-color reproduction images, by overlapping recording of ink materials several times, for example, magenta, yellow, and cyan ink materials are overlaid to produce secondary or tertiary colors. When obtaining a thermal ink layer of the present invention, the heat-sensitive ink material of the present invention is layered as at least the upper layer ink material, and since its transparency is good, the reflected light from the lower layer ink layer is also reduced due to the characteristics of the pigment itself. There is no color difference from the desired secondary or tertiary color, and by taking advantage of the properties of the polymeric material as a binding layer, that is, its slow melting properties, the heat dissipation of the applied energy in the ink material is reduced. It is possible to eliminate this problem and obtain excellent resolution. Furthermore, as a binder, s
Since the Z remer is used, the material is flexible and durable against friction, etc., and it is also possible to improve the poor fixability, which is a drawback of conventional wax-based heat-sensitive recording materials.

(2 others)

Claims (1)

[Scope of Claims] 1. A recording material in which a layer of heat-melting heat-sensitive ink material is provided on a support, wherein the heat-sensitive ink material has a glass transition temperature of 4.
A heat-sensitive recording material characterized in that it is a material whose main components are an amorphous polyester resin having a number average molecular weight of 10,000 or less at a temperature of 0° C. or higher and a colorant. 2. Amorphous polyester resin has a glass transition temperature of 50
The heat-sensitive recording material according to claim 1, which is an aromatic polyester containing a bisphenol component having a number average molecular weight of 5,000 or less at a temperature of 80°C to 80°C.