JP2001353972A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent poor curing using a curing agent, migration of a low molecular weight siloxane compound to an ink layer, adhesion to a thermal head when using at a high temperature, contamination of a thermal head, and the like. To provide a thermosensitive recording material having a backing layer having a property. SOLUTION: A back layer containing a polysiloxane segment introduced from the following polysiloxane compound in the molecular chain and an ultraviolet-curable urethane-based polymer having an unsaturated bond introduced from glycerin monoallyl ether or the like is formed. Thermal recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-resistant protective layer (back layer) for an ink ribbon used in a thermal printer or the like.
Relates to a heat-sensitive recording material formed of a composition containing a UV-curable siloxane-modified polyurethane.

[0002]

2. Description of the Related Art Conventionally, an ink ribbon used in a thermal printer or the like has a thin polyester film as a base material, a melt-type thermal transfer ink layer provided on an upper surface of the base material, and a surface (contacting with a thermal head) on a lower surface of the base material. The back layer (also called a heat-resistant lubricating layer or a heat-resistant protective layer) is made of a heat-resistant resin such as a polyamide resin or a silicone resin or a thermoplastic resin such as an acrylic resin, a polyurethane resin, or a polyester resin, and an organic polyisocyanate-based curing agent. It is formed of a film cured by the above method. Conventionally, lubricating agents such as silicone and various waxes have been added to these films to impart lubrication.

[0003] Since these resins are used as thermosetting resins which are cured with various crosslinking agents, various problems have arisen. For example, when the back layer is formed using polyisocyanate as a crosslinking agent, the pot life
Problems such as insufficient curing or poor curing due to mixing of water or insufficient aging may occur, resulting in heat resistance,
Various properties such as adhesion to the substrate and film strength are insufficient, which causes printing defects.

[0004] An ink ribbon used in a thermal printer or the like is produced by applying an ink layer and a back layer continuously or in separate steps. In the method of continuously applying the ink layer and the back layer, the back layer is in an uncrosslinked state because the ink layer and the back layer are wound up in a roll before aging. Therefore, since the unreacted polyisocyanate is present, the stacked ink layer and the back layer are blocked, and ink transfer to the back layer occurs, causing contamination or printing trouble of the printer or its surroundings. Such a problem also occurs.
Further, when the lubricant added for imparting lubrication is used for a long period of time, there is also a problem that bleeding occurs on the surface of the back layer or transfer to the ink layer, thereby hindering printing.

[0005] It is also possible to form a back layer by applying a material comprising an ultraviolet-curable silicone-containing monomer and a reactive diluent, followed by drying and ultraviolet-curing. However, since a low-molecular-weight reactive silicone-containing monomer is used as the ultraviolet-curable silicone compound, the unreacted silicone-containing monomer remains, which has a low molecular weight and easily bleeds out. After the removal, the unreacted silicone-containing monomer migrates to the ink layer, causing a problem of causing a fatal deterioration of the ink transferability.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a conventional thermosensitive recording material with a backing layer formed by using a curing agent. There is no problem of printing failure or ink transfer at the time of printing due to insufficient curing due to insufficient aging, and it has excellent low silicone transferability, heat resistance, adhesion, and further improvement in productivity.
An aging process that also achieves energy saving and space saving (to sufficiently perform curing using a curing (crosslinking) agent)
The object of the present invention is to provide a heat-sensitive recording material which does not require a heat-sensitive recording material.

[0007]

The above object is achieved by the present invention described below. That is, the present invention provides a heat-sensitive recording material comprising a base sheet and a heat-sensitive recording layer provided on one surface thereof and a back layer provided on the other surface, wherein the back layer is a polyisocyanate, a polyol or a polyamine, A polysiloxane having at least one active hydrogen-containing group in the molecule and a polysiloxane having at least one unsaturated bond and at least one active hydrogen-containing group in the molecule having 2 to 2 carbon atoms;
A heat-sensitive recording material comprising a layer containing a siloxane-modified polyurethane obtained by reacting 50 compounds with a chain extender as required.

[0008]

Next, the present invention will be described in more detail with reference to preferred embodiments of the present invention. The heat-sensitive recording material of the present invention has the same structure as a conventional heat-sensitive recording material in which a heat-sensitive recording layer is formed on one surface of a base sheet and a back layer is formed on the other surface. It is characterized by being formed of a UV-curable siloxane-modified polyurethane having an unsaturated bond which is cured by irradiation. The ultraviolet-curable silicone-modified polyurethane of the present invention comprises at least one polyisocyanate, polyol or polyamine, which is a raw material for producing ordinary polyurethane, which is a feature of the present invention.
Polysiloxane having at least one active hydrogen-containing group and a compound having at least one unsaturated bond and at least one active hydrogen-containing group in the molecule, if necessary, by reacting with a chain extender. Polyurethane. This reaction is the same as a normal polyurethane formation reaction. In the present invention, polyurethane is a general term for polyurethane, polyurea and polyurethane-polyurea.

The raw material components used for producing the ultraviolet-curable silicone-modified polyurethane of the present invention will be described below. As the compound having an unsaturated bond and an active hydrogen-containing group in the same molecule, a compound having about 2 to 50 carbon atoms is preferable, for example, a compound having a polyfunctional hydroxyl group and a derivative thereof (e.g., glycerin, trimethylolethane, Trimethylolpropane, glycerin pentaerythritol, erythritol, sorbitols and the like and low alkylene oxide adducts (number average molecular weight less than 500)]
Unsaturated bond-introducing compounds such as glycerin monoallyl ether, monoallyl ether of glycerin tripolyethylene oxide adduct, glycerin tri (meth) acrylate, di (meth) acrylate of glycerin tripropylene oxide adduct, pentaerythritol tri ( Meth) acrylates and the like; low molar addition products of alkylene oxides of unsaturated bond-containing bisphenols (number average molecular weight less than 500);

Hydroxyl-containing monomers, for example, (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, and allyl Alcohols and the like; hydroxyl-containing acetylenes, for example,

[0011] Etc .; an ester obtained by subjecting a hydroxy acid such as dimethylolpropionic acid or dimethylolbutanoic acid to a transesterification reaction with a compound having a hydroxyl group and an unsaturated bond, such as pentaerythritol triallyl ether or trimethylolpropane diaryl ether. Saturated group-containing short-chain diols, one-terminal isocyanate reaction products obtained by reacting an amino alcohol such as diethanolamine with an isocyanate compound such as hexamethylene diisocyanate or isophorone diisocyanate and a hydroxyl group such as pentatrititol triallyl ether and unsaturated Compounds having an unsaturated bond and an active hydrogen-containing group, such as an unsaturated group-containing short-chain diol obtained by reacting a compound having a bond with the compound, are exemplified. These can be used alone or in combination of two or more.

The chemical formulas of representative compounds of the above examples are shown below.

[0013]

The polysiloxane used to introduce a polysiloxane segment into the molecular chain of the ultraviolet-curable siloxane-modified polyurethane used in the present invention contains at least one active hydrogen-containing group such as an amino group, It is a reactive polysiloxane having a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group and the like. The reactive polysiloxane may further have an unsaturated group. Preferred examples of the polysiloxane having an active hydrogen-containing group include the following compounds.

(1) Amino-modified polysiloxane

[0016]

(2) Epoxy-modified polysiloxane

(3) Hydroxyl-modified polysiloxane compound

[0019]

[0020]

[0021]

(4) Mercapto-modified polysiloxane

(5) Carboxyl-modified polysiloxane

[0024]

The polysiloxanes having an active hydrogen-containing group listed above are examples of preferred compounds used in the present invention, and the present invention is not limited to these exemplified compounds. Therefore, not only the above-mentioned exemplified compounds but also other compounds which are currently commercially available and can be easily obtained from the market can be used in the present invention.

As the polyol and polyamine which are the raw materials for the production of ordinary polyurethane, conventionally known short-chain diols, short-chain diamines, high-molecular polyols and the like can be used without any particular limitation. Examples of the short-chain diol include ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol,
1,3-propanediol, 1,2-butanediol,
1,3-butanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-
Aliphatic glycols such as octanediol, 1,9-nonanediol, neopentyl glycol, and low-molecular-weight alkylene oxide adducts thereof (number average molecular weight of less than 500); 1,4-bishydroxymethylcyclohexane;
Alicyclic glycols such as cyclohexane-1,4-diol and the like, and low-molecular-weight adducts of alkylene oxide thereof (number-average molecular weight: less than 500); aromatic glycols such as xylylene glycol and the like; (Number average molecular weight less than 500); compounds such as alkyl dialkanolamines such as C ₁ -C ₁₈ alkyl diethanolamine. Examples of polyhydric alcohol compounds include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, tris- (2-hydroxyethyl) isocyanurate, 1,1,1-trimethylolethane, 1,1,1 −
Trimethylolpropane and the like. These can be used alone or in combination of two or more.

Examples of the short-chain diamine include aliphatic polyamines such as ethylenediamine, N-hydroxyethylethylenediamine, tetramethylenediamine, hexamethylenediamine, and diethylenetriamine; alicyclic polyamines such as 4,4-diaminodicyclohexyl Methane, 1,4-diaminocyclo hexane, isophorone diamine and the like; hydrazines such as hydrazine,
Carbodihydrazide, adipic dihydrazide, sebacic dihydrazide, phthalic dihydrazide and the like; polyamines containing an unsaturated group, for example, diallylamine compound and the like. These can be used alone or in combination of two or more.

Examples of the polymer polyol include: (1) a polyether polyol such as an alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or a heterocyclic ether (tetrahydrofuran, etc.) polymerized or copolymerized; What is obtained, specifically, polyethylene glycol, polypropylene glycol, polyethylene-polypropylene (block or random) glycol, polyethylene-polytetramethylene glycol (block or random), polytetramethylene ether glycol, polyhexamethylene ether glycol, etc.

(2) Polyester polyol, for example,
Aliphatic dicarboxylic acids (eg, succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, etc.) and / or
Or aromatic dicarboxylic acids (eg, isophthalic acid,
Terephthalic acid, etc.) and low molecular weight glycols (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4- Dihydroxymethylcyclohexane), specifically, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyneopentyl adipate diol, polyethylene / butylene adipate diol, polyneopentyl / hexyl adipate Diols, poly-3-methylpentane adipate diol,
Such as polybutylene isophthalate diol,

(3) Polylactone polyol, for example,
Polycaprolactone diol or triol, poly-3
(4) polycarbonate polyols such as methylvalerolactone diol, for example, (5) polyolefin polyols such as polyhexamethylene carbonate diol,
For example, (6) polymethacrylate diols such as polybutadiene glycol, polyisoprene glycol or hydrides thereof, for example, α, ω-polymethyl methacrylate diol, α, ω-polybutyl methacrylate diol, etc. Although the molecular weight of these polyols is not particularly limited, usually the number average molecular weight is 500 to 2.0.
It is about 00. These polyols can be used alone or in combination of two or more.

As the polyisocyanate, any known polyisocyanate can be used. For example, preferred are aromatic diisocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and m-xylylene diisocyanate. Isocyanates (XDI), naphthalene diisocyanate, etc .; aliphatic diisocyanates having 2 to 12 carbon atoms, for example,
Hexamethylene diisocyanate (HMDI), lysine diisocyanate, etc .; alicyclic diisocyanates having 4 to 18 carbon atoms, for example, 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane Diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-
4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane (hydrogenated XDI) and the like; aliphatic diisocyanates having an aromatic ring and the like. These can be used alone or as a mixture of two or more. Furthermore, these polyisocyanates can also be used as a polyurethane prepolymer or the like obtained by reacting a low molecular weight polyol component or a polyamine so that the terminal becomes an isocyanate group.

In the present invention, the method for producing the ultraviolet-curable polysiloxane-modified urethane using the above raw materials is not particularly limited, and a conventionally known method for producing polyurethane can be used. For example, in the presence or absence of an organic solvent containing no active hydrogen in the molecule, the above-mentioned diisocyanate, polymer polyol, polysiloxane having an active hydrogen-containing group, and active hydrogen-containing group and unsaturated A compound having a bond, if necessary, a low molecular weight diol or a low molecular weight diamine, and an equivalent ratio of an isocyanate group and an active hydrogen-containing functional group is usually set at a compounding ratio of 1.0,
By a one-shot method or a multi-stage method, usually 20 to 150
C., preferably from 60.degree. C. to 110.degree. C., until the isocyanate groups are almost eliminated to obtain a polyurethane. In the infrared absorption spectrum of the polyurethane of the obtained reaction product, no absorption due to free isocyanate groups at 2,270 cm ^-1 was observed, and -SiO at 1,090 cm ^-1 .
- absorption band based on, 1,640cm ^-1, 990cm ^-1,
An absorption band based on> C = C <was observed at 905 cm ^-1 .

The polysiloxane segment in the ultraviolet-curable siloxane-modified polyurethane used in the present invention is contained in the main chain and / or the side chain, and the content of the polysiloxane segment in the polyurethane (JIS K0117)
Is preferably 1 to 75% by weight, more preferably 1 to 60% by weight. When the content of the polysiloxane segment is less than 1% by weight,
Adhesion with substrate, heat resistance, chemical resistance, stain resistance, lubricity,
Properties such as water repellency and oil repellency become insufficient, and if it exceeds 75% by weight, the properties of the polysiloxane segment become strong,
It is not preferable because the adhesion to the substrate, mechanical strength, abrasion resistance and the like are reduced.

The content of unsaturated bonds in the ultraviolet-curable siloxane-modified polyurethane of the present invention (JIS K00
70 according to the element number method) is 0.001 to 10
The range of meq / g (polymer) is preferable, more preferably 0.001 to 5 meq / g (polymer), and most preferably 0.005 to 0.5 meq / g (polymer). If it is less than 0.001 meq / g (polymer), the strength of the coating after ultraviolet curing is insufficient, and the adhesion to the substrate may be poor. On the other hand, if it exceeds 10 meq / g (polymer), the UV-cured coating is hard and brittle,
Deformation of the substrate occurs. Further, the physical properties of the coating may be reduced due to steric hindrance or the like due to a high crosslinking density. Also, the weight-average molecular weight (GP) of the ultraviolet-curable siloxane-modified polyurethane
Measured at C. Standard polystyrene conversion. ) Is 5,000-
A range of 200,000 is preferred.

The ultraviolet-curable siloxane-modified polyurethane according to the present invention as described above has excellent adhesiveness to various materials, as well as excellent solvent resistance, chemical resistance, stain resistance, water repellency, and oil repellency. , Slippery, non-stick,
Since it is excellent in transferability, high hardness, mechanical strength, abrasion resistance, and flexibility, it is particularly useful as a back layer forming material of a thermal transfer material of a thermal transfer system or a sublimation transfer system.

The heat-sensitive recording material of the present invention can be produced by a conventionally known method, and the production method itself is not particularly limited. In addition, as the materials other than the back layer forming material such as the base sheet and the thermosensitive recording layer (ink layer) forming material, any conventionally known materials can be used, and there is no particular limitation. When forming the back layer of the heat-sensitive recording material of the present invention, a back layer forming paint containing the ultraviolet-curable siloxane-modified polyurethane containing an unsaturated group of the present invention is applied to the back surface of the substrate sheet by a conventionally known coating method. (The surface is a heat-sensitive recording layer) is coated so as to have a dry thickness of about 0.01 to 1 μm to form a film, and is cured (crosslinked) by irradiation with ultraviolet light or heating.

The coating for forming the back layer can be used as one liquid containing only the ultraviolet-curable siloxane-modified polyurethane. However, in order to further improve the physical properties, a crosslinking agent and / or a reactive diluent may be used in combination. preferable. As the cross-linking agent, any of those conventionally used as a cross-linking agent for an ultraviolet-curable polymer or a polyurethane can be used, and is not particularly limited. For example, a polyfunctional (meth) acrylate, a polyisocyanate, a melamine resin, an epoxy resin, or the like, or a derivative thereof may be used.

As the reactive diluent, those which are conventionally known as reactive diluents such as UV-curable polymers such as photopolymerizable monofunctional monomers and polyfunctional monomers, polyfunctional oligomers and cationically polymerizable monomers can be used. Can be used without any particular limitation. Examples of the photopolymerizable monofunctional monomer include tetrahydrofurfuryl (meth) acrylate, methoxyethyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, lauryl (meth) acrylate, Examples thereof include (meth) acrylates such as -ethylhexyl (meth) acrylate, diethylene glycol di (meth) acrylate, and 1,6-hexanediol mono (meth) acrylate, and acrylate is preferred from the viewpoint of reaction rate. Also, vinyl monomers such as N-vinylpyrrolidone can be used.

The polyfunctional monomer functions as a reactive diluent before curing the polyurethane, and functions as a crosslinking agent during curing. Examples of the polyfunctional monomer include diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol hexa (meth) acrylate. And bifunctional or more (meth) acrylates such as pentaerythritol tetra (meth) acrylate, and polyfunctional acrylate is preferable. Examples of the polyfunctional oligomer include polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate, and the like. Examples of the cationic polymerizable diluent include an epoxy compound, an oxetane compound, and a vinyl ether compound. These crosslinking agents and reactive diluents can be used alone or in combination of two or more. The amounts of the cross-linking agent and the reactive diluent are not particularly limited, and vary depending on the type of the substance to be used and the case where the reactive diluent is also used as the cross-linking agent, and cannot be specified unconditionally. Usually, the proportion of the crosslinking agent is about 10 to 60 parts by weight, and the proportion of the reactive diluent is about 50 to 600 parts by weight, based on 100 parts by weight of the ultraviolet-curable siloxane-modified polyurethane.

In the present invention, it is preferable to use a photopolymerization initiator. As the photopolymerization initiator, those that generate radicals by light and initiate the radical polymerization of the above monofunctional and polyfunctional monomers are preferable, and any conventionally known radical reaction type photopolymerization initiator can be used,
There is no particular limitation. For example, benzophenone, acetophenone, benzoin, benzoin isobutyl ether,
Benzoin isopropyl ether, benzoin ethyl ether, 2,4-dimethylthioxanthone, 2-chlorothioxanthone, ethylanthraquinone, 4,4'-bisdimethylaminobenzophenone, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one, benzyldimethyl ketal and the like. Although cationic photopolymerization initiator is used when using the cationic polymerizable diluent, for example, aryl diazonium salt type compound _{^{(Ar-N 2 + X -}} : X - PF 6 is ^-, SbF ₆ ^- , BF
₄ ^- etc.), triarylsulfonium salt type compounds (Ar ₃
S ⁺ X ⁻ : X ⁻ is the same as above), and diaryliodonium salt type compounds (Ar ₂ I ⁺ X ⁻ : X ⁻ is the same as above).
These photopolymerization initiators can be used alone or in combination of two or more in accordance with the type of the crosslinking agent or diluent to be used. The amount of the photopolymerization initiator is not particularly limited, and is usually used at a ratio of about 1 to 5 parts by weight per 100 parts by weight of the ultraviolet-curable siloxane-modified polyurethane.

In the paint for forming the back layer used in the present invention, orthonitrotoluene, hydroquinone, hydroquinone monomethyl ether, copper chloride and the like are polymerized in order to control the thermal polymerization of the crosslinking agent and the reactive diluent during storage. It is preferred to mix as an inhibitor. Further, as other additives, an antioxidant, a light stabilizer, a paint additive, a function-imparting agent, and the like can be appropriately compounded.

[0042]

EXAMPLES The present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited thereto. Also, "parts" in the following text are parts by weight,
“%” Indicates% by weight.

Production Examples 1 to 5, Comparative Production Examples 1 to 4 The polysiloxane, polyol, chain extender, and compound having an unsaturated bond and an active hydrogen-containing group shown in Tables 1 and 2 were used in the number of parts shown in the table. And hexamethylene diisocyanate 1
1 part, MEK / toluene (105/105 parts) was charged into a reaction vessel and heated with stirring.
Add 85 parts of dibutyltin dilaurate to 85 ° C
The mixture was allowed to react for 4 hours, and it was confirmed by IR that there was no residual NCO group. Thus, a siloxane-modified polyurethane having or not having an unsaturated bond was synthesized. Comparative Production Example 4
Is a methacryl-modified silicon compound dissolved in toluene. Tables 1 and 2 show each raw material composition and properties and strength characteristics (uncrosslinked) of each obtained polyurethane (measured according to JIS K6301). The content of the polysiloxane segment in each polyurethane was determined according to JIS K0
The content of unsaturated bonds was measured by the infrared spectroscopy method of No. 117 by the element number method such as JIS K0070.

[0044]

[0045]

[0046]

A-1 and A-2 and methacryl-modified silicone compounds in Tables 1 and 2 are the following compounds. Methacryl-modified silicone compound: X manufactured by Shin-Etsu Chemical Co., Ltd.
-22-164B

Examples 1 to 5 and Comparative Examples 1 to 4 100 parts of the polyurethane solution (solid content: 30%) obtained in each of the Production Examples and Comparative Production Examples were each added with a reactive diluent in each of the Examples and Comparative Examples 4. Pentaerythritol as 30
Parts / 100 parts of polyurethane, and Comparative Examples 1 to 30 30 parts / curing agent (hexamethylene diisocyanate trimer (buret bond), NCO% = 24%) / polyurethane 1
By adding 00 parts, a paint for forming the back layer of the heat-sensitive recording material was prepared. Each of these paints was applied to the surface of a 6 μm-thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc.) by gravure printing so that the thickness after drying was 0.3 μm, and the solvent was removed in a dryer. An uncrosslinked back layer was formed. Next, in each of Examples and Comparative Example 4, a metal halide lamp was irradiated from above the coated surface with a peak illuminance of 382 mW / cm ² and an irradiation intensity of 415 mj / cm ² to crosslink, thereby forming a back layer for a comparative test. Comparative Examples 1 to 3 were aged for one day in an atmosphere of 40 ° C. and a humidity of 46% to form a crosslinked back layer.

On the opposite side of the PET film on which the back layer was formed, the transfer ink composition prepared according to the formulation shown in Table 3 was heated to 100 ° C., and the coating thickness was adjusted by roll coating using a hot melt. A transfer ink layer (heat-sensitive recording layer) was formed by coating to a thickness of 5 μm to obtain a heat-sensitive recording material of the present invention.

Using each of the heat-sensitive recording materials of the examples and comparative examples obtained above, a thin-film thermal head was used.
Printing was performed under the printing energy condition of 1 mj / dot (4 × 10 ⁻⁴ cm ² ), and sticking property, head contamination property and transfer property were observed. Further, the adhesion between the back layer and the substrate and the coefficient of static friction of the back layer were measured. Table 4 shows these results.
Shown in The results are displayed and measured as follows. [Sticking property] Visually observe the releasability of the thermal recording material from the thermal head during the pressing operation between the thermal head and the thermal recording material when the thermal recording material is subjected to the mounting test. 5, a five-step evaluation was performed with the case where the worst release property was the worst.

[Dirt of Thermal Head] Observation was made on the state of dirt on the thermal head when the thermal recording material was subjected to a mounting test, and a five-level evaluation was made, with 5 being the least dirt and 1 being the most dirt. went. [Adhesion] The back layer was evaluated by a cross-cut cellophane tape peel test. [Coefficient of static friction] It was measured using a surface property tester (manufactured by Shinto Kagaku). [Transferability] The degree of transfer of the unreacted polysiloxane to the ink layer after leaving the heat-sensitive transfer material wound into a roll in an oven at 40 ° C. for 3 days was evaluated by finger touch and visual observation. A five-point evaluation was performed where 5 was not observed and 1 was when migration was clearly observed.

[0052]

[0053]

According to the present invention, there is provided a heat-sensitive recording material which is free from sticking phenomenon and blocking phenomenon and has excellent heat resistance and lubricity. In particular, the back layer can be formed by curing with ultraviolet rays, and the productivity can be improved. Further, since the transfer of the silicon component to the heat-sensitive recording layer and the bleeding are small, there is provided a heat-sensitive recording material having excellent performance such as not contaminating a thermal head or impairing printing characteristics.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuyuki Hanada 1-7-6 Nihombashi Bakurocho, Chuo-ku, Tokyo Inside Dainichi Seika Industries Co., Ltd. (72) Inventor Ken Kawaguchi 1-7 Nihonbashi Bakurocho, Chuo-ku, Tokyo No. 6 Dainichi Seika Kogyo Co., Ltd. (72) Inventor Etsuhiro Awaji 1-7-6 Nihombashi Bakurocho, Chuo-ku, Tokyo F-term inside Dainichi Seika Kogyo Co., Ltd. 2H111 AA01 AA26 AA33 BA08 BA53 BA55 BA61 BA64 BA73 BA78

Claims (7)

[Claims] 1. A thermosensitive recording material comprising a base sheet, a thermosensitive recording layer provided on one surface thereof, and a back layer provided on the other surface, wherein the back layer comprises a polyisocyanate, a polyol or a polyamine, A polysiloxane having at least one active hydrogen-containing group in the molecule and a compound having 2 to 50 carbon atoms having at least one unsaturated bond and at least one active hydrogen-containing group in the molecule, A heat-sensitive recording material comprising a layer containing a siloxane-modified polyurethane obtained by reacting with a chain extender as required. 2. The heat-sensitive recording material according to claim 1, wherein the content of the polysiloxane segment in the siloxane-modified polyurethane is 1 to 75% by weight. 3. The heat-sensitive recording material according to claim 1, wherein the content of unsaturated bonds in the siloxane-modified polyurethane is 0.001 to 10 meq / g (polymer). 4. A siloxane-modified polyurethane having a weight average molecular weight of 5,000 to 200,000.
4. The heat-sensitive recording material according to any one of 3. 5. The heat-sensitive recording material according to claim 1, wherein the back layer further contains a crosslinking agent and / or a reactive diluent. 6. The heat-sensitive recording material according to claim 1, wherein the back layer contains another binder resin. 7. The heat-sensitive recording material according to claim 1, wherein the back layer is a film cured by ultraviolet light or heat.