JPH0832485B2 - Thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal transfer recording medium, and more specifically, to a recording sheet such as a low smooth paper which has high transfer sensitivity and can be printed with low energy. The present invention relates to a heat-sensitive transfer recording medium capable of suppressing the occurrence of background stain (fog), excellent in fixing property to a recording sheet, and capable of obtaining a dye transfer image having high resolution.

[Prior Art and its Issues] Thermal transfer recording media have been conventionally used as recording media for transferring and forming images on recording sheets such as plain paper by a thermal printer or a thermal facsimile. There is.

This thermal transfer recording medium has at least one support on a support.
The layer has a color material layer. As this color material layer, for example, a layer containing a colorant composed of a dye such as a pigment and a heat-melting substance which is a low melting point substance such as wax or wax is known. Further, as the support, in order to obtain good reproducibility of the dye transfer image obtained from the color material layer coated thereon, films having excellent surface smoothness and dimensional stability are used. There is.

With respect to this type of conventional thermal transfer recording medium, various ideas and proposals have been made so that a printed image can be clearly transferred onto a recording sheet having a smooth surface with good fixability.

However, until now, there has been a strong demand for a heat-sensitive transfer recording medium capable of excellently transferring an image on a so-called low-smooth surface whose surface is not always smooth.

This is because, for example, when making a test print of a document with a thermal printer having a thermal head, it is not necessary to use expensive smooth paper at all, and it is preferable to use an inexpensive recording sheet having a low smooth surface. In many cases, the back surface of plain paper (which is usually a rough surface) that has become unnecessary after transferring the printed image to a smooth surface is used. Further, it is necessary to intentionally transfer an image to a recording sheet having a low-smooth surface in order to prevent forgery of the document or to bring out the characteristics of the destination of the document. Moreover, it is not that it is sufficient if the printed image is transferred to the low-smooth surface anyway. It has high transfer sensitivity, low energy, no character smear (fog), good fixing property and high resolution. There is an increasing need to form an image on a recording sheet having a particularly rough surface with a thermal transfer recording medium.

Despite such demands, various inventions and devices relating to the ink layer in the heat-sensitive transfer recording medium are mostly directed to plain paper having a smooth surface, and for low-smoothness paper, increase as described above. It is no exaggeration to say that there is almost no thermal transfer recording medium provided with an ink layer that satisfies all of the above requirements.

[Object of the Invention] An object of the present invention is to provide a thermal transfer recording medium capable of forming an image not only on a smooth surface but also on a low smooth surface with high transfer sensitivity and low energy. Is.

Another object of the present invention is to provide an image having high fixability, high resolving power and high printing quality while further suppressing the occurrence of fog not only on a smooth surface but also on a low smooth surface. A thermal transfer recording medium that can be formed.

Still another object of the present invention is to provide a thermal transfer recording medium capable of further reducing the load applied to the printer side, such as the winding torque.

[Means for Achieving the Object] As a result of earnest studies by the present inventors in order to achieve the object, a thermal transfer recording having a color material layer containing a heat-fusible substance and a color material on a support. The present invention has been achieved by finding that the above object can be achieved by adding a copolymer of a specific compound and a polyoxyethylene compound to the color material layer in a medium, particularly in combination.

That is, the gist of the present invention for achieving the above-mentioned object is a thermal transfer recording medium in which a color material layer containing a heat-fusible substance and a color material is formed on a support, wherein the color material layer is ethylene, The following formula (However, in the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a linear or branched alkyl group having 1 to 8 carbon atoms.) And a copolymer obtained from maleic anhydride and a polyoxyethylene-based compound, which is a thermal transfer recording medium.

--Copolymer-- The copolymer can be represented by the following second formula.

However, in the second formula, R ¹ represents a hydrogen atom or a methyl group.

R ² is a linear or branched alkyl group having 1 to 8 carbon atoms, for example, methyl group, ethyl group, n-prosol group, isopropyl group, butyl group, isobutyl group, t- Examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.

The above a, b and c represent a copolymerization ratio. Among them, when the total of a, b and c is 100%, the a is 50 to 90%, preferably 79 to 62%, and the b is 10 to 50%, preferably 20 to 35%, And c is 0.5 to 15%, preferably
It is desirable to be 0.5 to 10%.

As the copolymer represented by the second formula, specifically, for example, ethylene-ethyl acrylate-maleic anhydride copolymer, ethylene-propyl acrylate-maleic anhydride copolymer, ethylene-n- Butyl acrylate-maleic anhydride copolymer, ethylene-isobutyl acrylate-maleic anhydride copolymer, ethylene-pentyl acrylate-maleic anhydride copolymer,
Ethylene-hexyl acrylate-maleic anhydride copolymer, ethylene-octyl-acrylate-maleic anhydride copolymer, etc., and ethylene-ethyl methacrylate-maleic anhydride copolymer, ethylene-propyl methacrylate-maleic anhydride Copolymer, ethylene-n-butyl methacrylate-maleic anhydride copolymer, ethylene-isobutyl methacrylate-maleic anhydride copolymer, ethylene-pentyl methacrylate-free ice maleic acid copolymer, ethylene-hexyl Examples thereof include a methacrylate-maleic anhydride copolymer and an ethylene-octyl-methacrylate-maleic anhydride copolymer.

Further, a copolymer in which a part of maleic anhydride in the copolymer is hydrolyzed to form a maleic acid monomer unit, an alkyl acrylate and / or an alkyl having ethylene and an alkyl group having 1 to 8 carbon atoms A copolymer obtained by copolymerizing methacrylate and maleic acid can also be included in the copolymer in the present invention.

In short, this copolymer may be obtained by any production method as long as it can be produced from ethylene, an acrylic acid derivative and maleic anhydride.
For example, a copolymer obtained by simultaneously reacting ethylene, an acrylic acid derivative and maleic anhydride, and a copolymer obtained by first copolymerizing any two monomers of ethylene, an acrylic acid derivative and maleic anhydride. A copolymer obtained by copolymerizing the binary copolymer with any of the remaining monomers can also be included in the copolymer in the present invention. Furthermore, the copolymer in this invention is
It may be a block copolymer or a random copolymer.

However, the copolymer preferably used in the present invention has a Vicat softening point (according to ASTM D 1525) of 30 ° C. or higher and 200 ° C. or lower, a breaking elongation (JIS K 6301) of 200% or higher, and a breaking strength. (JIS K 6301) is 30 kg / cm ² or more. As long as it has such properties, it is preferable to use it by appropriately selecting it from the above-mentioned various copolymers.

The various copolymers may be used alone or in combination of two or more. Furthermore, this copolymer may be used by blending it with other known resins.

Among these various copolymers, those having a softening point (ring and ball method) of 200 ° C. or lower, particularly 30 to 200 ° C. are preferable. In addition, the melt flow index (MI)
However, it is 1 g / 10 minutes or more, preferably 1 to 400 g / 10 minutes, particularly preferably 1 to 50 g / 10 minutes, and further preferably 1.5 to 40 g.
Copolymers within the range of 10 minutes are desirable.

Such a copolymer can be obtained, for example, from "BONDINE HX-8140" [Sumitomo CDF, MI, MI
= 20g / 10min], "BONDINE AX-8040" [Sumitomo CDI, MI, MI
= 4.5g / 10min], "BONDINE HX-8020" [Sumitomo CDI, MI, MI
= 10g / 10min], "BONDINE HX-8060" [Sumitomo CDI, MI, MI
= 10g / 10 minutes], "BONDINE HX-8290" [Sumitomo CDI, MI, MI
= 65g / 10min], “BONDINE HX-82l0” [Sumitomo CDF, MI, MI
= 200g / 10min], "NUC-ACE GA-003" [Made by Nippon Unicar Co., Ltd., MI = 1.7g]
/ 10 minutes], "NUC-ACE GA-004" [Made by Nippon Unicar Co., Ltd., MI = 1.8g]
/ 10 minutes], “NUC-ACE GA-201” [Nippon Unicar Co., Ltd., M1 = 5.0g]
/ 10 minutes], “NUC-ACE GA-301” [Nippon Unicar Co., Ltd., M1 = 4.0g]
/ 10 minutes] and can be obtained commercially.

--Polyoxyethylene-based compound-- Next, the polyoxyethylene-based compound, in the molecule,
The formula _{- (CH 2 CH 2 O)} n - (3) [ provided that in the third formula, n represents located on 2 or more integer, preferably an integer of 4 to 50. ] There is no particular limitation as long as it is a compound having a moiety represented by However, the polyethylene compound is preferably a derivative rather than a compound in which both ends thereof are -OH. For example, by reacting one or two alcoholic hydroxyl groups of polyethylene glycol with various organic compounds to form ether bond, ester bond, bond with sulfur atom or nitrogen atom, urethane bond and other various bond forms. And derivatives thereof. In addition, this connection form is not particularly essential in the present invention and is not particularly limited.

Rather, blocking performance, prevention of bleed-out,
Appropriate derivatization should be performed based on molecular design such as cohesive force and viscosity optimization, molecular weight, miscibility with heat-fusible substances and number of polar groups. Preferred inductions include ether inductions. This is because the color material layer containing the ether-derived polyoxyethylene compound is generally excellent in blocking performance.

In any case, as the polyoxyethylene-based compound that can be used in the present invention, those having a melting point or a softening point of 30 to 120 ° C., particularly 40 to 100 ° C. and being in a solid state or a semi-solid state are preferable.

Further, when a plurality of polyoxyethylene chains represented by the third formula are contained in the molecule, the total molecular weight of the polyoxyethylene chain portion represented by the third formula may greatly affect the effect of the present invention.

The preferred molecular weight of the polyoxyethylene chain portion represented by the above formula 3 depends on the molecular weight of the entire compound or the structure or molecular weight of the compound other than the polyoxyethylene portion, but in many cases, 40 to 20000 as the total molecular weight,
40 to 2000 are particularly preferable.

Examples of polyoxyethylene compounds having such a molecular weight include the following various compounds.

(1) Poly (ethylene glycol) mono- or di-ester derivatives Those belonging to this category include, for example, 8 to 50 carbon atoms.
The fatty acid esterified derivatives thereof include, for example, (a) linear monoenoic acid, (b) polyenoic acids such as dienoic acid, trienoic acid and tetraenoic acid, (c) synthetic and natural fatty acids, (d) ) Secondary fatty acids and tertiary fatty acids, (e) direct tack fatty acids and branched fatty acids, (f) dimer acids, (g) polybasic acids such as dibasic acids and acid-basic acids, (h) oxycarboxylic acids, (i) ) Fatty acid chlorides,
Examples include (j) a fatty acid anhydride, and (k) a mono- or diglycol of polyethylene glycol and a compound containing one or more carboxyl groups in the molecule.

Among these, preferred are caprylic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, octacosanoic acid, and mericic acid having 8 to 30 carbon atoms.
There are some fatty acids, especially mono- or diesters of polyethylene glycol esters with monocarboxylic acids such as nonadecanoic acid, arachidic acid, heneicosanoic acid, behenic acid, brassic acid, tricosanoic acid, lignoceric acid, pentacosanoic acid. To be

Compared with polyethylene monoester, polyethylene glycol exhibits excellent dispersibility in the color material layer composition, has an excellent effect of not deteriorating the dispersibility of the color material, and has a smooth surface. It is excellent in that a high-density printed image can be stably transferred onto the surface of a recording sheet having a low density. Therefore, the polyethylene glycol diesters of the above-mentioned various fatty acids can be pointed out as preferred polyoxyethylene compounds in the present invention.

In the case of a diester, the two polyoxyethylene chains ester-bonded to the two carboxylic acids may have the same or different molecular weight or structure.

Specific examples of the diester include polyethylene glycol distearate [PEG 4000], polyethylene glycol dibehenate [PEG 14000], polyethylene glycol dipalmitate [PEG 600] and polyethylene glycol dilaurate [PEG 100]. Can be mentioned. The number in [] indicates the average molecular weight of the polyoxyethylene chain.

(2) Alkyl, arylalkyl, araryl or aryl monoether of polyoxyethylene glycol (derivative in which one hydroxyl group of polyoxyethylene glycol is etherified) Examples of compounds belonging to this category include ether residues. An alkyl having 6 or more carbon atoms, preferably 18 to 50 carbon atoms,
Examples include araryl monoether derivatives. In addition,
The alkyl group and araryl group may be linear or branched.

Specific examples thereof include polyethylene glycol mono-p-nonylphenyl ether, polyethylene glycol monobehenyl ether, polyethylene glycol monooleyl ether and the like.

Furthermore, in this invention, as a special case, the ether residue may be derived from unsaturated hydrocarbon, synthetic alcohol, oxycarboxylic acid, nitrogen-containing compound and sulfur-containing compound.

(3) An ether or ester derivative of the monoether derivative shown in (2), that is, the residual hydroxyl group in the monoether derivative of polyethylene glycol is ether- or ester-derived.

In this case, the ester derivative conforms to the case (1), and the ether derivative conforms to the case (2).

Specifically, polyethylene glycol mono-p-nonylphenyl ether monobehenate [PEG 800], polyethylene glycol monostearyl ether monostearate [PEG 9000], polyethylene glycol dibehenyl ether [PEG 6000], polyethylene glycol monooleyl ether. Monobehenyl ether [PEG 400
0] and the like.

(4) Polyoxyethylene glycol ether derivative of polyhydric alcohol As the polyhydric alcohol, a compound having two or more alcoholic hydroxyl groups in the molecule, for example, glycerin,
Propylene glycol, pentaerythritol, polypropylene glycol, sorbitan (1,5-sorbitan,
1,4-sorbitan, 3,6-sorbitan, isosorbite, etc.), mannitol, and poval having a molecular weight of 800 or less.

Furthermore, two or more sets of polyhydric alcohols are
It may also be bound by a polyoxyethylene chain or other molecular chain.

The indicated polyoxyethylene glycol ether derivative is one in which polyoxyethylene glycol is ether-bonded to one hydroxyl group of the polyhydric alcohol, and the remaining hydroxyl group of the polyhydric alcohol is converted to the above (1) and (2 ), Which is ether-derived (which is a polyoxyethylene glycol diether derivative) or ester-derived residual hydroxyl groups.

Moreover, from another viewpoint, the notation polyoxyethylene glycol ether derivative may have one or more polyoxyethylene chains in its molecule. The hydroxyl group at the end of the polyoxyethylene chain of this polyoxyethylene glycol ether derivative is preferably ester-derived or ether-derived according to the above (1) or (2).

Specific examples of the indicated polyoxyethylene glycol ether derivative are shown below.

Glycerin polyoxyethylene monostearate, glycerin di (polyoxyethylene monostearate), sorbitan monobehenate polyoxyethylene monobehenate, batyl alcohol polyoxyethylene ether, propylene glycol monooleate polyoxyethylene Monooleate, block copolymer of polypropylene glycol and polyoxyethylene glycol, polyoxyethylene ether behenate of pentaerythritol distearyl ether, polyoxyethylene ether of sorbitan ester, polyoxyethylene ether of pentaerythritol, polyglycerin Ester polyoxyethylene ether, ester of batyl alcohol ester polyoxyethylene ether, mannito (5) Polyoxyethylene ethers of esters, (5) Polyoxyethylene derivatives of molecules having a sulfur atom or a nitrogen atom, specific examples of those belonging to this category include alkylthiopolyoxyethylene, polyoxyethylene fatty acid amites, polyoxyethylene alkylamines and the like. Is mentioned.

(6) Polymer or Copolymer Polyoxyethylene Derivatives Specific examples of the compounds belonging to this category include alkylarylformaldehyde aldehyde condensed polyoxyethylene ethers, copolymer polyoxyethylene ether esters,
Examples thereof include polyoxyethylene ether derivatives of α-olefin maleic anhydride copolymer.

(7) Block polymer of synthetic polymer such as polyester or polyurethane and polyoxyethylene glycol (8) Compound having anionic property As such a compound, for example, carboxylate of polyoxyethylene alkyl ether, polyoxyethylene aryl Ether carboxylate, polyoxyethylene fatty acid ester sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene aryl ether carboxylate, polyoxyethylene alkyl ether phosphate, polyoxyethylene aryl ether Polyoxyethylene-containing anions such as phosphates, polyoxyethylene alkylamide phosphates, polyoxyethylene arylamide phosphates, and carboxylates of polyoxyethylene fatty acid esters Activator etc. are mentioned.

(9) Compound Having Cationic Property Examples of such a compound include an alkyl polyoxyethylene ether ammonium salt, an aryl polyoxyethylene ether ammonium salt, and a polyoxyethylene hydroxyammonium salt.

Various polyoxyethylene compounds have been exemplified above. By mixing such a polyoxyethylene compound with the copolymer, the heat-meltable compound and the coloring material in the present invention, a coloring material layer composition is obtained. Can be prepared.

During the preparation, the polyoxyethylene-based compound may not be mixed in the color material layer composition in a sufficiently dispersed state depending on its type. For example,
When the polyoxyethylene chain has a large molecular weight of 1000 or more, the miscibility of the polyoxyethylene compound with the copolymer, the heat-meltable substance described later, or the like may decrease.

However, although the reason is not always clear, even if the polyoxyethylene compound is in a clear dispersed state, a pseudo mixed state, or a mixed state in the color material layer composition, The effect can be reflected.

—Coloring Material Layer— The coloring material layer in the present invention contains a coloring material and a heat-fusible substance like the conventional heat-sensitive transfer recording medium, but the copolymer and the polyoxyethylene-based material are used. Its major feature is that it contains a compound. further,
When a specific adhesive resin is contained as the third component, the effect of the present invention can be enhanced.

Examples of the adhesive resin as the third component include rosins such as gum rosin, tall rosin, and wood rosin; hydrogenation, disproportionation, dimerization, esterification, liming of these rosins, and modification thereof in combination. Obtained modified rosins; terpene resins, hydrogenated modified terpenes and terpene phenolic resins; natural resins such as dammar, cobal and shellac; aliphatic, aromatic, copolymeric and alicyclic and coumarone indene resins Petroleum resins; oil-soluble phenol resins such as alkylphenol resins and modified phenol resins, and xylene-based resins such as xylene resins and modified xylene resins. Among these, natural resin-based resins such as rosin, modified rosin, terpene resin, and hydrogenated modified terpene, and petroleum resins such as C5 and C9 are preferable.

Furthermore, among the above-mentioned various types, the softening point is 60 ° C to 130 ° C.
Adhesive resins in the range of ° C are preferred.

--Heat-melting substance-- Examples of the heat-melting substance include ester waxes (natural ester waxes such as carnauba wax and montan wax; Hoechst Wax E manufactured by Hoechst Co.,
Synthetic ester waxes such as F, KP, KPS, BJ, OP, OM, X22, U, and O), oxidized wax (paraffin wax, wax obtained by oxidizing wax such as microcrystalline wax, Nippon Seiro Co., Ltd. ) Made of NPS-921
0, NPS-6114, PETRONABA C, C made by Toyo Petrolite Co., Ltd.
ARDIS 314 and Hoechst Wax SL and LP from Hoechst, low molecular weight polyethylene wax (especially with a molecular weight of 30)
POLYWAX 5 manufactured by Toyo Petrolite Co., Ltd.
00 and 655), paraffin wax (145,150,155, HNP-3, HNP-10 manufactured by Nippon Seiro Co., Ltd.), microwax (Nisseki Microwax manufactured by Nippon Ishibiki Co., Ltd.)
155, 180, etc. HI-MIC-1080, HI-MIC- manufactured by Nippon Seiro Co., Ltd.
2065, HI-MIC-2095, HI-MIC-1070, HI-MIC-1045, HI-MIC-20
STA WAX 100, BE S manufactured by Toyo Petrolite Co., Ltd.
QUARE 175,185, VICT0RY, ULTRAFLEX, etc. and other higher fatty acids such as stearic acid, myristic acid, behenic acid, margaric acid, etc., higher alcohols such as stearyl alcohol, behenyl alcohol, marganyl alcohol, myricyl alcohol, eicosanol, palmitin Higher fatty acid esters such as cetyl acid, myricyl palmitate, cetyl stearate, milsyl stearate, dodecyl stearate, wooden wax, auri curry wax,
Examples thereof include plant waxes such as espal wax, beeswax, insect wax, shellac wax, animal waxes such as whale wax, stearone, sorbitan monostearate, and polyoxyethylene monostearate. In addition to these, an olefin polymer wax made of a copolymer of maleic anhydride and an α-olefin such as ethylene, propylene, or butene-1 can be preferably used.

The above-mentioned various heat-meltable substances may be used alone or in combination of two or more.

Among these various heat-meltable substances, ester wax, paraffin wax, olefin polymer wax and the like are preferable, and carnauba wax, paraffin wax and polyethylene wax are particularly preferable.

--Colorant-- The colorant to be contained in the color material layer in the present invention can be appropriately selected from conventionally known dyes and used, and examples thereof include direct dyes, acid dyes, basic dyes, disperse dyes and oil-soluble dyes. It is possible to select from dyes and the like at will. The dye used in the color material layer in the present invention may be any dye that can be transferred (transferred) together with the heat-meltable substance,
Besides the above, pigments can also be used.

Specifically, as the yellow pigment, for example, Kayaron Polyester Light Yellow 5G-S (product of Nippon Kayaku Co., Ltd.), Oil Yellow S-7 (white clay), Eisenspiron GRH Special (product of Hodogaya Chemical Co., Ltd.) ) And the like. Examples of the red dye include, for example, Diaceriton Fast Red R (product of Mitsubishi Kasei Co., Ltd.), Dianex Brilliant Red BS-E (product of Mitsubishi Kasei Co., Ltd.), Sumiplast Tread FB (Sumitomo). Chemical Industry Co., Ltd.), Sumiplast Tread HGF (Sumitomo Chemical Co., Ltd. product), Kayaron Polyester Pink RCL-E (Nippon Kayaku Co., Ltd. product), Aizenspiron Red GEH Special (Hodogaya Chemical Co., Ltd.) ) Products) and the like, and examples of blue dyes include diaceriton fast brilliant blue R (product of Mitsubishi Kasei Co., Ltd.), dye Anix Blue EB-E (Mitsubishi Kasei Co., Ltd. product), Kayaron Polyester Blue B-SF Conc (Nippon Kayaku Co., Ltd. product), Sumiplast Blue 3R (Sumitomo Chemical Co., Ltd. product), Sumiplast Blue G (Sumitomo Chemical Co., Ltd. product) and the like. Examples of yellow pigments include Hansa Yellow 3G (Sumitomo Chemical Co., Ltd. product) and Tartrazine Lake. Examples of red pigments include Brilliant Carmine FB-Pure (Sanyo Dye Co., Ltd. product). , Brilliant Carmine 6B (product of Sanyo Dye Co., Ltd.), Alizarin Lake, and the like. Examples of blue pigments include Cerulean Blue, Sumika Print Cyanine Blue GN-0 (Product of Sumitomo Chemical Co., Ltd.), Phthalocyanine Blue, etc. As the black pigment,
Examples thereof include carbon black and oil black.

--Additive Material-- In the color material layer of the present invention, various additives may be added in addition to the above-mentioned components unless the object of the present invention is impaired.

As such an additive, for example, as a softening agent,
Vegetable oils such as castor oil, linseed oil and olive oil, animal oils such as whale oil and mineral oils can be preferably used.

--- Blending of Each Component --- Composition of the copolymer, the polyoxyethylene compound, the heat-fusible substance, the colorant and, if necessary, the third component adhesive resin forming the coloring material layer in the present invention The proportion is not limiting. Normally, for the total amount of color material layer,
The blending amount of the copolymer is 5 to 40% by weight, and the blending amount of the polyoxyethylene compound is 0.5 to 20% by weight, preferably 1 to 10% by weight. When the tacky resin as the third component is compounded, the compounding ratio thereof is 0.5 to 20% by weight, preferably 3 to 15% by weight, based on the total amount of the color material layer. Regarding the heat-fusible substance, the total amount of the color material layer is 100 parts by weight (hereinafter, “parts by weight” is abbreviated as “part”)
The amount is 5 to 90 parts, preferably 10 to 80 parts, and the colorant is 5 to 40 parts, preferably 10 to 20 parts.

The copolymer, the polyoxyethylene compound, the heat-fusible substance, the colorant and, if necessary, the adhesive resin as the third component and various additives can be added by a conventionally known method. There is a method of mixing the above components at one time.

In order to obtain a color material layer composition in which the respective components such as the copolymer and the polyoxyethylene compound are sufficiently mixed,
It is preferable to use a disperser such as a dissolver, a mixer, a sand grinder, or a ball mill for each of the above components. The particle size dispersed by these dispersers is 10 μm.
The following is good.

The dispersed state can be easily examined by observing the coloring material composition excluding the coloring material in a hot melt state or in a coated state. From this observation, when the sea / island structure is formed, or when it becomes cloudy, or in a droplet (oil droplet) state or a phase-separated state, it can be determined that this is an immiscible state.

--Support (Substrate)-It is preferable that the support as a substrate used in the heat-sensitive transfer recording medium according to the present invention has heat resistance strength and high dimensional stability and surface smoothness. In addition, this support has heat resistance strength that does not cause softening or plasticization due to heating by a heat source such as a thermal head, and also has mechanical strength and dimensional stability as a support. It is desirable that the coloring material layer on the body has sufficient smoothness so as to exhibit a good transfer rate.

The smoothness is preferably 100 seconds or longer in a Beck tester smoothness test (JKS P 8ll9), and when it is 300 seconds or longer, a reproducible image can be obtained with a better transfer rate. it can.

Examples of the material for the support having the above-mentioned preferable properties include papers such as plain paper, condenser paper, laminated paper, and coated paper, polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyimide, and polyamide. Preferred examples include sheets or films of thermoplastic resin such as (nylon), composites of the paper sheets and the thermoplastic resin film or sheet, metal sheets such as metal foils of aluminum, and the like. To be

In order to obtain good thermal conductivity, the thickness of this support is
Usually, it is about 60 μm or less, and particularly preferably 2 to 20 μm. The thermal transfer recording medium according to the present invention is
The structure of the back surface of the support is arbitrary. That is, a sticking layer may be coated on the back surface of the support, if necessary.

--Formation of Coloring Material Layer on Support ---- Techniques suitable for forming the coloring material layer on the surface of the support are known in the technical field of this type. Therefore, the heat-sensitive transfer recording according to the present invention. With respect to the medium as well, the color material layer can be formed on the surface of the support by using such a known technique.

For example, the color material layer can be formed by hot-melt coating the composition, or solvent-coating a coating solution prepared by dissolving or dispersing the composition in a solvent. As the coating method, for example, a reverse roll coater method, an extrusion coater method, a gravure coater method, a wire bar coater method, or any other technique can be adopted. The thickness of the color material layer is usually 15 μm, preferably 1 to 9
μm.

The thermal transfer recording medium thus obtained has a breaking strength of 30 kg / cm ² or more, particularly 45 kg / cm ² or more, and a breaking elongation of 2% or more, particularly 5% or more Can be done.

EFFECTS OF THE INVENTION According to the present invention, in a heat-sensitive transfer recording medium in which a coloring material layer containing a heat-fusible substance and a coloring agent is formed on the surface of a support, a special copolymer and a poly Since it contains an oxyethylene compound, (1) It is possible to further suppress the occurrence of fog on not only plain paper with a smooth surface but also low smooth surface, and high transfer sensitivity. In addition, it is possible to transfer a high-resolution printed image with low energy, good fixing property, and (2) It is possible to reduce the winding torque and reduce the load on the printer. A recording medium can be provided.

EXAMPLES Examples will be shown below, but the present invention is not limited to the following examples. In addition, "part" in the following
Indicates “part by weight”.

(Example 1) 15% by weight of carbon black, 4% by weight of polyethylene glycol monobehenyl ether (PEG n = 10) as a polyoxyethylene compound, paraffin wax (melting point)
68 ° C) 40% by weight, polyethylene wax (melting point 64
(° C) 11% by weight, as an ethylene-ethyl acrylate-maleic anhydride copolymer (trade name: Bondine HX-8140;
Sumitomo CDF Co., Ltd .; Copolymer consisting of 3 wt% maleic anhydride, 19 wt% ethyl acrylate, and 78 wt% ethylene] 15 wt% and Diacarna 30
[Mitsubishi Kasei Co., Ltd.] A coloring material layer composition having a composition of 15% by weight is applied to a surface of a polyethylene terephthalate film support having a thickness of 3.5 μm so as to have a dry thickness of 5.0 μm, and thermal transfer is performed. A recording medium sample was obtained.

This thermal transfer recording medium sample was applied with a thermal printer (prototype equipped with a thin film line thermal head with a heating element density of 8 dots / mm) to 400g / head and 600g on low smooth paper with Beck smoothness of 10 seconds. / Printing was performed with the printing pressure of the head. Then, when stains other than the printed portion were observed with a magnifying glass, there was no background stain at all.

(Example 2) In Example 1, ethylene-ethyl acrylate-
Ice-free maleic acid copolymer [trade name: Bondine HX-8140;
Sumitomo CDF Co., Ltd.], MI = 65g / 10
Of ethylene-ethyl acrylate-maleic anhydride copolymer [trade name: Bondine HX-8290; Sumitomo CDF Co., Ltd .; 3% by weight of maleic anhydride, 17% by weight of ethyl acrylate, and 80% by weight of ethylene] Copolymer] was used in the same manner except that the same amount was used to obtain a thermal transfer recording medium sample.

This thermal transfer recording medium sample was printed at a printing pressure of 400 g / head in the same manner as in the above example. And
When stains other than the printed portion were observed with a magnifying glass, there was no background stain.

(Example 3) In Example 1, ethylene-ethyl acrylate-
Maleic anhydride copolymer [trade name: Bondine HX-8140;
Sumitomo CDF Co., Ltd.], MI = 200g / 1
0 minutes ethylene-ethyl acrylate-maleic anhydride copolymer [trade name: Bondine HX-8210; manufactured by Sumitomo CDF, Inc .; 3% by weight maleic anhydride, 6% by weight ethyl acrylate, and 91% by weight ethylene] Was used in the same manner as above to obtain a thermal transfer recording medium sample.

This thermal transfer recording medium sample was printed at a printing pressure of 400 g / head in the same manner as in the above example. And
When stains other than the printed portion were observed with a magnifying glass, there was no background stain.

(Example 4) 15% by weight of carbon black and polyethylene glycol distearate (Mw as polyoxyethylene compound)
= 400) 10% by weight, ester wax 8% by weight, paraffin 45% by weight, terpene resin 10% by weight, and ethylene-ethyl acrylate-maleic anhydride copolymer [trade name: Bondine HX-8140; Sumitomo] 12% by weight. The color material layer composition having the above composition was applied on the surface of a polyethylene terephthalate film support having a thickness of 3.5 μm so as to have a dry thickness of 5.0 μm to obtain a thermal transfer recording medium sample.

This thermal transfer recording medium sample was printed at a printing pressure of 400 g / head in the same manner as in the above example. And
When stains other than the printed portion were observed with a magnifying glass, there was no background stain.

(Examples 5 to 13) 15% by weight of carbon black, 10% by weight of a polyoxyethylene compound of the kind shown in Table 1, and ester wax 8
%, Paraffin 45% by weight, terpene resin 10%, and ethylene-ethyl acrylate-maleic anhydride copolymer [trade name: Bondine HX-8040; Sumitomo CDF Co., Ltd .; maleic anhydride 2% by weight, ethyl Copolymer consisting of 30% by weight of acrylate and 68% by weight of ethylene], a coloring material layer composition having a composition of 12% by weight, 3.5 μm
It was coated on the surface of a thick polyethylene terephthalate film support to a dry thickness of 5.0 μm to obtain a heat-sensitive transfer recording medium sample.

Using 9 thermal transfer recording media thus obtained, 300 g of low thermal paper having Beck smoothness of 10 seconds was prepared by using the same thermal printer as used in Example 1 above.
A checkerboard pattern was printed with the print pressure of the / head and observed with a magnifying glass to observe and evaluate the print quality. The results are shown in Table 1. The symbols in Table 1 indicate the following evaluation contents.

⊚: The printed edge is sharp.

◯: The print edge is slightly broken.

X: Defects and blurring occur in printing.

Further, the ink rupture elongation and the ink rupture strength of the thermal transfer recording medium samples according to Examples 5 and 6 were measured according to ASTM D638.

 The results are shown in Table 2.

(Example 14) In Example 5, except that the ester wax content was O and the bondine content was 20% by weight,
A thermal transfer recording medium sample was obtained in the same manner as in Example 6.

The print quality of this thermal transfer recording medium was evaluated in the same manner as in the above-mentioned examples. The results are shown in Table 1.

With respect to this thermal transfer recording medium sample, the ink breaking elongation and the ink breaking strength were measured in the same manner as in Examples 5 and 6 above.

 The results are shown in Table 2.

(Example 15) In Example 5, the amount of ester wax blended was changed.
A thermal transfer recording medium sample was obtained in the same manner as in Example 5 except that the content of Pondyne AX-8040 was 17% by weight and the mixing ratio of Pondine AX-8040 was 3% by weight.

The print quality of this thermal transfer recording medium was evaluated in the same manner as in the above-mentioned examples. The results are shown in Table 1.

With respect to this thermal transfer recording medium sample, the ink breaking elongation and the ink breaking strength were measured in the same manner as in Examples 5 and 6 above.

 The results are shown in Table 2.

(Comparative Examples 1 to 3) Thermal transfer recording medium samples were obtained in the same manner as in Example 3 except that the compounds shown in Table 1 were blended in place of the polyoxyethylene-based compound, and the same as in the above Examples. And the print quality was evaluated. The results are shown in Table 1.

As is clear from Tables 1 and 2, it can be seen that the thermal transfer recording medium samples according to the present invention can perform high-quality printing on low-smoothness paper without scumming. .

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Claims (1)

[Claims] 1. A heat-sensitive transfer recording medium having a color material layer containing a heat-fusible substance and a color material formed on a support, wherein the color material layer comprises ethylene and (However, in the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a linear or branched alkyl group having 1 to 8 carbon atoms.) And a copolymer obtained from maleic anhydride and a polyoxyethylene-based compound, which is a heat-sensitive transfer recording medium.