JP3164383B2 - Reversible thermosensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible thermosensitive recording material capable of repeatedly forming and erasing an image by utilizing a reversible change in transparency of a thermosensitive layer depending on the temperature.

[0002]

2. Description of the Related Art In recent years, a reversible thermosensitive recording material which can form a temporary image and erase the image when it becomes unnecessary has been attracting attention. A typical example is a glass transition temperature (Tg) of 50 to 60 ° C to 8 ° C.
A reversible thermosensitive recording material is known in which an organic low molecular weight substance such as a higher fatty acid is dispersed in a resin base material such as a vinyl chloride-vinyl acetate copolymer having a low glass transition temperature of less than 0 ° C. JP-A-54-119377, JP-A-55-1
No. 54198).

In this reversible thermosensitive recording material, when an image is formed with a heating element such as a thermal head, the surface of the reversible thermosensitive recording material is flawed by repeating the image formation and erasing several times due to the heat and pressure of the thermal head. However, there is a disadvantage that the surface is gradually scraped off and image formation becomes impossible. In addition, the scraps that have been removed adhere to the thermal head,
There is a drawback to cause the image cut or the like. In order to solve these drawbacks, measures have been taken to reduce the heat and pressure of the thermal head, but the image forming and erasing methods are insufficient and have not been solved yet.

Further, although measures added heat resistance and lubricity to the surface at the recording material surface is taken, Oite to use <br/> middle of a card, said to be printed on the surface in approach has poor adhesion and printing bad problems such as printing, not resolved failure due to still head chippings adhered.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks and solves the above problem even if the image forming and erasing operations are repeated many times with a heating element such as a thermal head, and even if the heat and pressure of the thermal head are high. It is an object of the present invention to provide a reversible thermosensitive recording material which is free from scratches and head scum and has good printability.

[0006]

According to the present invention, on a support, a resin base material and an organic low-molecular substance dispersed in the resin base material are used as main components. In a reversible thermosensitive recording material provided with a heat-sensitive layer whose state reversibly changes, an intermediate layer mainly composed of a heat-resistant resin is provided on the heat-sensitive layer, and a silicone-modified polyurethane resin and a polyisocyanate are further provided thereon. A reversible thermosensitive recording material is provided, which is provided with a slip protection layer containing a crosslinked cured product as a main component, and on a support, a resin base material and an organic material dispersed in the resin base material are provided. In a reversible thermosensitive recording material having a low-molecular substance as a main component and a heat-sensitive layer in which a transparent state and a cloudy state are reversibly changed depending on a temperature, a printing layer is provided on the heat-sensitive layer. Silicone-modified polyurethane resin and Provided is a reversible thermosensitive recording material provided with a lubricating protective layer containing a crosslinked cured product with a lyisocyanate as a main component, and an intermediate layer and a protective layer between the thermosensitive layer and the printing layer. Are provided in order, and the reversible thermosensitive recording material is characterized in that, in the reversible thermosensitive recording material, the intermediate layer is mainly composed of an ultraviolet curable resin, and the lubricating protective layer is modified with silicone. A crosslinked cured product of a polyurethane resin, an amino-modified silicone oil and a polyisocyanate as a main component, a ratio of the polyisocyanate to the silicone-modified polyurethane resin in the range of 6: 4 to 2: 8, and a silicone-modified polyurethane resin Tensile strength (JIS K
−6301) is 300 kg / cm ² or more, and the elongation (JIS)
K-6301) is 100% or less.

The inventors of the present invention have made a reversible thermosensitive recording material resistant to the heating and pressure of a thermal head or a heat roll and the like. Focusing on improving the heat resistance and pressure resistance of the surface of the layer and the intermediate layer, and reducing the coefficient of friction with the thermal head, the material of the thermal protective layer or the slip protective layer and the intermediate layer on the surface of the print layer As a result of various studies, it was confirmed that a heat-resistant resin was used for the intermediate layer material as a material having good adhesion and high heat resistance and high friction resistance, and in particular, an ultraviolet curable resin was optimal.
Further, as a material for the lubricating protective layer, a resin obtained by crosslinking and curing a silicone-modified polyurethane resin and a polyisocyanate was preferable, and it was confirmed that the friction resistance was improved by adding an amino-modified silicone oil.

Hereinafter, the present invention will be described in more detail. The slip protective layer of the present invention is obtained by crosslinking and curing a silicone-modified polyurethane resin and a polyisocyanate. The silicone-modified polyurethane resin used in the present invention is a copolymer having a urethane bond in the main chain and a structure partially having a siloxane bond, which is incorporated in a block shape and / or a graft shape. Any ratio can be used for the ratio of the unit of the structure having a siloxane bond to the structural unit of the main chain. The tensile strength (JIS K-6301) of the silicone-modified polyurethane resin is 300 kg /
100% elongation (JIS K-6301) at least ² cm2
It is desirable to use: Tensile strength is 3
If it is smaller than 00 kg / cm ² , the surface will be scratched after repeating image formation to erasure several times with a thermal head,
There is a problem that the scratch becomes a head residue and a problem of image breakage occurs. When the elongation is more than 100%, the image formation and erasure are repeated several times with the thermal head.
There is a problem that the cloudiness density decreases and durability deteriorates.

The slip protective layer of the present invention further comprises an amino-modified silicone oil for improving the friction resistance of the surface of the protective layer. The amino-modified silicone oil is a compound having an amino group at a terminal or a side chain of a siloxane segment, and preferred examples include compounds represented by the following formulas (1) to (7).

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As the polyisocyanate used in the present invention, a general polyisocyanate can be used, but a dimer, trimer or polyisocyanate of polyisocyanate is preferable.
Polyurethane polyisocyanate having a relatively high molecular weight obtained by reacting a polyol compound is preferred. These polyisocyanates include, for example, Takenate (manufactured by Takeda Pharmaceutical), Vernock (manufactured by Dainippon Ink and Chemicals), Coronate (manufactured by Nippon Polyurethane), Duranate (manufactured by Asahi Kasei Kogyo), Dismodule (manufactured by Bayer), Polyisocyanate XD
I, TDI (manufactured by Morohoshi Ink), CROSNATE (manufactured by Dainichi Seika Kogyo) and the like can be used in the present invention.

The amounts of the silicone-modified polyurethane resin, the amine-modified silicone oil and the polyisocyanate are related to the cross-linked structure of the slip protective layer to be formed. Is used in the range of 6: 4 to 2: 8, preferably 5: 5 to 3: 7. When the ratio of the polyisocyanate to the silicone-modified polyurethane resin is 7: 3 to 10: 0, the properties of the polyurethane are strongly exhibited, the softening point is lowered to 200 ° C. or less, and the heat resistance is insufficient. When the ratio of the polyisocyanate to the modified polyurethane resin is 1: 9 to 0:10, the properties of the polyurethane are weakened, and the flexibility of the slip protective layer, that is, the so-called tensile strength is reduced. Problems such as scraping of the protective layer occur.
The amino-modified silicone oil can be used in a proportion of 0.1 to 10 wt% of the total of the three, and is preferably 0.5 to 5 wt%. If the amount is too small, sufficient lubricity cannot be obtained, and if it is too large, problems such as insufficient strength and adhesiveness of the slip protective layer occur.

In order to further improve heat resistance and lubricity, the lubricating protective layer of the present invention further comprises, in addition to the above materials, conventionally known organic lubricants, silica, calcium carbonate, precipitated barium sulfate, urea resin crosslinked powder, acrylic resin. Fine particles such as crosslinked powder, silicone resin powder, wood powder, molybdenum dioxide, and nitrogen nitride can be included.

The lubricating protective layer of the present invention is prepared by dissolving the above-mentioned materials in an appropriate solvent such as acetone, methyl ethyl ketone, toluene, xylene or the like to prepare a coating solution, and applying this coating solution to a gravure coater. It is formed by coating with a conventional coating means such as a roll coater, a wire bar, or the like, and reacting the silicone-modified polyurethane resin, amine-modified silicone oil and polyisocyanate during coating and heating and drying to form a crosslinked resin layer. Is done. The crosslinked structure is sufficiently formed by treating at a temperature of 50 to 100 ° C. for several hours to several days. Of course, in this reaction, a curing catalyst or the like can be used.

The thickness of the slip protective layer of the present invention is from 0.01 to 0.01.
2.0 μm, preferably 0.1 to 1.5 μm
Sufficient performance can be obtained with a thickness of m.

As the material of the intermediate layer of the present invention, a thermosetting resin or a thermoplastic resin can be used. That polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyesters, unsaturated polyesters, epoxy resins, phenolic resins, polycarbonates, and polyamides and the like, ultraviolet as a stronger material in heat resistance and pressure resistance Curable resins are optimal. That is, when image formation to erasure is repeated several times with a thermal head, the intermediate layer has excellent heat resistance and pressure resistance and is hard, so that peeling of the intermediate layer due to heat and pressure of the thermal head can be prevented. The thickness of the intermediate layer of the present invention is in the range of 0.1 to 10 μm, preferably 0.1 to 10 μm.
Sufficient performance can be obtained with a thickness of 5 to 5 μm.

The printing layer of the present invention is not particularly limited, but an ultraviolet curable ink is preferably used.

When a printing layer is provided, a protective layer can be provided in advance to protect the heat-sensitive layer. As the material of the protective layer (thickness: 0.1 to 10 μm) laminated on the heat-sensitive layer, silicone rubber or silicone resin (Japanese Patent Laid-Open No.
No. 221087), polysiloxane graft polymer (described in Japanese Patent Application No. 62-152550), ultraviolet curable resin or electron beam curable resin (Japanese Patent Application No. 63-3106).
No. 00). In any case, a solvent is used at the time of coating, and it is preferable that the solvent does not easily dissolve the resin of the thermosensitive layer and the organic low-molecular substance. Examples of the solvent that hardly dissolves the resin and the organic low-molecular substance in the heat-sensitive layer include n-hexane, methyl alcohol, ethyl alcohol, and isopropyl alcohol, and an alcohol-based solvent is particularly desirable in terms of cost.

Hereinafter, the present invention will be described in more detail.
The reversible thermosensitive recording material in which the transparent state and the cloudy state are reversibly changed by heat in the present invention is a type in which an organic low-molecular substance is dispersed in a resin, a polymer blend type,
Examples include a type utilizing a phase change of a liquid crystal polymer or the like, but are not limited thereto. That the in the resin used in the present invention to disperse the organic low-molecular material is composed mainly of a resin matrix and an organic low molecular weight substance dispersed in the resin base material, transparency depending on the temperature Is a reversible thermosensitive recording material provided with a reversible thermosensitive layer. This reversible thermosensitive recording material utilizes the change in transparency (transparent state, cloudy opaque state) as described above,
The difference between the transparent state and the cloudy opaque state is presumed as follows. That is, (i) in the case of transparency, the particles of the organic low-molecular substance dispersed in the resin base material are composed of large particles of the organic low-molecular substance, and the light incident from one side is not scattered and is opposite. (Ii) In the case of cloudiness, the particles of the organic low-molecular substance are composed of polycrystals composed of fine crystals of the organic low-molecular substance, and the crystal axes of the individual crystals Is oriented in various directions, so that light incident from one side will be refracted many times at the interface of the crystals of the organic low-molecular-weight material particles, and will be scattered and appear white.
And so on.

In FIG. 1 (representing a change in transparency due to heat), a heat-sensitive layer mainly composed of a resin base material and an organic low-molecular substance dispersed in the resin base material is, for example, T
_At a room temperature of ₀ or less, it is cloudy and opaque. This is called temperature T ₂
When the temperature is returned to room temperature below T ₀ , the film remains transparent. This is from temperature T ₂ to T ₀
It is considered that the crystal grows from a polycrystal to a single crystal through the semi-molten state of the organic low-molecular substance until the following.
Upon further heating to T ₃ or more temperature becomes translucent state intermediate between the maximum transparency and the maximum opacity. Then, if we lower this temperature, the phrase things take a transparent state again, back to the first of the cloudy opaque state. This after low-molecular organic material is melted at a temperature T ₃ or more, presumably because the polycrystals precipitated by being cooled. When the opaque state is heated to a temperature between T _{1 and} T ₂ and then cooled to room temperature, that is, a temperature lower than T ₀ , an intermediate state between transparent and opaque can be obtained. Also, by returning to room temperature after heating to be again T ₃ or more temperature which became clear at the normal temperature, the flow returns to cloudy opaque state again. That is, both opaque and transparent forms at room temperature and intermediate states thereof can be taken.

Therefore, the heat-sensitive layer can be selectively heated by selectively applying heat to form a cloudy image on a transparent ground and a transparent image on a cloudy ground, and the change can be repeated many times. It is possible. If a colored sheet is disposed on the back of such a heat-sensitive layer, an image of the color of the colored sheet on a white background or an image of a white background on the colored background of the colored sheet can be formed. Further, when projected by an OHP (overhead projector) or the like, the cloudy portion becomes a dark portion, the transparent portion transmits light, and becomes a bright portion on the screen.

[0021] Such a reversible thermosensitive recording To do erased and forming an image of a material, or with two thermal head for image erasing imaging, or changing the applied energy condition Accordingly, the use of those having a single thermal head for image formation and image erasing are valid. In the former case, although two thermal heads up the cost of the apparatus because it requires, if passed once a reversible thermosensitive recording material of energy application conditions for each of the thermal head to separate, forming an image and erasing the You can do it. In the latter case, in order to form and erase an image with one thermal head, the condition for applying energy to the thermal head at one time when the thermal recording material passes is adjusted according to the part where the image is formed and the part to be erased. Although the operation is complicated, the operation is complicated, for example, the image is formed under different energy conditions by changing the thermal recording material in a small direction or by erasing the image on the thermal recording material once and then running the thermal recording material in the opposite direction again. Therefore, the equipment cost is reduced.

In order to produce the reversible thermosensitive recording material used in the present invention , for example , it is formed as a film on a support member such as a plastic film, a glass plate, a metal plate or the like by the following method , or formed into a sheet. be able to. 1) A method of dissolving a resin base material and an organic low-molecular substance in a solvent, applying this on a support member, and evaporating the solvent to form a film or sheet. 2) The resin base material is dissolved in a solvent in which only the resin base material is dissolved, and the organic low-molecular substance is pulverized or dispersed therein by various methods, applied to a support member, and the solvent is evaporated to form a film. Or a method of forming a sheet. 3) A method in which a resin base material and an organic low-molecular substance are heated and melted and mixed without using a solvent, and the resulting mixture is formed into a film or sheet and cooled. The solvent for preparing the heat-sensitive layer or the heat-sensitive recording material can be variously selected depending on the type of the resin base material and the organic low-molecular substance, and examples thereof include tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene, and benzene. No. In addition, of course, when a dispersion is used,
Even when a solution is used, in the heat-sensitive layer obtained, the organic low-molecular substance is precipitated as fine particles and exists in a dispersed state.

In the present invention, the resin used as the resin base material of the heat-sensitive layer of the reversible thermosensitive recording material is preferably a resin which can form a film or sheet, has good transparency, and is mechanically stable. Examples of such a resin include polyvinyl chloride; vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, and vinyl chloride-acrylate copolymer. Vinylidene chloride-based copolymer such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer; polyester; polyamide; polyacrylate or polymethacrylate or acrylate -Methacrylate copolymers; silicone resins and the like. These may be used alone or as a mixture of two or more.

On the other hand, the organic low-molecular substance may be any substance that changes from polycrystal to single crystal by heat in the recording layer (a substance that changes in the temperature range of T _{1 to} T ₃ shown in FIG. 1). generally a melting point of 30 to 200 ° C., preferably 50 to 1
What it is about 50 ° C. is used. Such organic low molecular weight substances include alkanols; alkane diols; halogen alkanols or halogen alkane diols;
Alkylamine; alkane; alkene; alkyne; halogen alkane; halogen alkene;
Cycloalkanes; cycloalkenes; cycloalkynes; saturated or unsaturated mono- or dicarboxylic acids or their esters, amides or ammonium salts; saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; allylcarboxylic acids or their esters Amides or ammonium salts; halogen allylcarboxylic acids or their esters, amides or ammonium salts; thioalcohols; thiocarboxylic acids or their esters, amines or ammonium salts; carboxylic acid esters of thioalcohols. These may be used alone or in combination of two or more. These compounds have 10 to 60 carbon atoms, preferably 10 to 38 carbon atoms, particularly 10 to 3 carbon atoms.
0 is preferred. The alcohol group in the ester may be saturated, may not be saturated, and may be halogen-substituted. In any case, the organic low molecular weight substance contains at least one of oxygen, nitrogen, sulfur and halogen in the molecule.
Species, such as -OH, -COOH, -CONH, -COO
_{R, -NH, -NH 2, -S} -, - S-S -, - O-,
A compound containing halogen or the like is preferable.

More specifically, these compounds include lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, pentadecanoic acid, stearic acid, arachinic acid, behenic acid, henicosanoic acid, tricosanoic acid,
Higher fatty acids such as lignoceric acid, pentacosanoic acid, serotinic acid, heptacosanoic acid, montanic acid, melisic acid, nonadecanoic acid, and oleic acid; methyl stearate, tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate, and behenic acid esters of higher fatty acids dodecyl; C ₁₆ H ₃₃ -O
-C ₁₆ H ₃₃ , C ₁₆ H ₃₃ -SC ₁₆ H ₃₃ , C ₁₈ H _{37
-S-C 18 H 37, C} 12 H 25 -S-C 12 H 25, C 19
_{H 39 -S-C 19 H 39} , C 12 H 25 -S-S-C 12 H 25
, And ether or thioether. Among them, in the present invention, higher fatty acids, especially palmitic acid, pentadecanoic acid,
Nonadecanoic acid, arachiic acid, stearic acid, behenic acid,
Higher fatty acids having 16 or more carbon atoms, such as lignoceric acid, cellotic acid, margaric acid, henicosanoic acid, and tricosanoic acid, are preferred, and higher fatty acids having 16 to 24 carbon atoms are more preferred.

Further, in order to widen the range of temperatures that can be made transparent, the organic low-molecular substance described in this specification is appropriately combined, or such an organic low-molecular substance is mixed with another material having a different melting point. You can combine them. These are described, for example, in JP-A-63-39378 and JP-A-63-1303.
No. 80, and Japanese Patent Application Nos. 63-14754 and 1-140109, but the present invention is not limited thereto.

The ratio between the organic low-molecular substance and the resin base material in the heat-sensitive layer is preferably about 2: 1 to 1:16, more preferably 1: 1 to 1: 3 by weight. Since the ratio of the resin base material is less than this, the organic low-molecular material becomes difficult to form the film held in the resin base material and above which, too small amount of the organic low-molecular material, opaque Becomes difficult. The thickness of the heat-sensitive layer is <br/> is preferably 1 to 3 [mu] m, and further preferably from 2 to 20 [mu] m. If the heat-sensitive layer is too thick, heat distribution within the layer will occur, making it difficult to achieve uniform transparency. On the other hand, if the heat-sensitive layer is too thin, the turbidity decreases and the contrast decreases. Further, the turbidity can be increased by increasing the amount of the organic low-molecular substance in the heat-sensitive layer.

In addition to the above components, additives such as a surfactant and a high-boiling solvent can be added to the heat-sensitive layer in order to facilitate formation of a transparent image. Specific examples of these additives are as follows. Examples of high boiling solvents: tributyl phosphate, tri-2-ethylhexyl phosphate,
Triphenyl phosphate, tricresyl phosphate, butyl oleate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, phthalate Dioctyldecyl acid, diisodecyl phthalate, butylbenzyl phthalate, dibutyl adipate, di-n-hexyl adipate, di-2-adipate
Ethylhexyl, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate, methyl acetyl ricinoleate, methyl acetyl ricinoleate, butyl phthalyl Butyl glycolate, tributyl acetyl citrate.

Examples of surfactants and other additives; polyhydric alcohol higher fatty acid ester; polyhydric alcohol higher alkyl ether; polyhydric alcohol higher fatty acid ester, higher alcohol, higher alkylphenol, higher fatty acid higher alkylamine, higher fatty acid amide Lower olefin oxide adducts of fats and oils or polypropylene glycol; acetylene glycol; Na, Ca, Ba or Mg salts of higher alkylbenzene sulfonic acids; higher fatty acids, aromatic carboxylic acids, higher fatty acid sulfonic acids, aromatic sulfonic acids, monoesters of sulfuric acid Or Ca, Ba or Mg salts of phosphoric acid mono- or di-esters; low sulfated oils; poly long chain alkyl acrylates; acrylic oligomers;
Poly long chain alkyl methacrylate; long chain alkyl methacrylate-amine-containing monomer copolymer; styrene-maleic anhydride copolymer; olefin-maleic anhydride copolymer.

When an image formed on the recording material is used as a reflection image, it is desirable to provide a light reflecting layer on the back surface of the recording layer. Further, the presence of the reflective layer can increase the contrast even if the thickness of the recording layer is small.
Specific examples include vapor deposition of Al, Ni, Sn and the like (described in JP-A-64-14079).

[0031]

EXAMPLES All parts and percentages herein are by weight. Example 1 A solution consisting of 200 parts of THF (tetrahydrofuran) 20 parts of behenic acid 6 parts eicosane diacid 4 parts diallyl phthalate 2 parts vinyl chloride-vinyl acetate copolymer 20 parts on a 50 μm-thick transparent polyester film Is applied with a wire bar and dried by heating.
Thus, a thermosensitive layer (reversible thermosensitive recording layer) having a thickness of about 15 μm was provided. Further thereon, an (intermediate layer Formulation) a polyamide resin consisting of (manufactured by Toray Industries, Inc. CM8000) 90 parts 10 parts of ethyl alcohol solution was coated with a wire bar, heated and dried
Then, an intermediate layer having a thickness of about 1.5 μm is provided, and further thereon (prescription of a slipping protective layer): 120 parts of silicone-modified polyurethane resin (solid content: 20%) (tensile strength: 380 kg / cm 2 (JIS K-6301)) (25% elongation (JIS K-6301)) polyisocyanate 32 parts (Yuroneto L, Nippon polyurethane industry Co. 75% solids) comprised of MEK 848 parts solution was coated by a wire bar, dried by heating, A slip protection layer having a thickness of about 1.0 μm was provided. The resulting reversible thermosensitive recording material, further I row heat cured at 10 days dryer at 50 ° C., was prepared a reversible thermosensitive recording material of the present invention.

[0032] The intermediate layer of Example 1, instead of the following ultraviolet crosslinking curing resin solution, and the coating thickness 3 [mu] m, after coating and drying 80W / c
perform curing treatment with ultraviolet lamps m, except for forming the intermediate layer, the same procedure as in Example 1 to prepare a reversible thermosensitive recording material of the present invention. (Intermediate layer formulation) UV-crosslinkable curable resin urethane acrylate 10 parts (Dainippon Ink & Chemicals, Inc. Unidic C7-157 solid content 75%) Toluene 10 parts

[0033] Except for using the following lubricous protective layer solution was added Example 3 lubricous protective layer in the amino-modified silicone oil of Example 2, in the same manner as in Example 2, a reversible thermosensitive recording material of the present invention It was created. (Lubricous protective layer formulation) silicone-modified polyurethane resin (20% solids) 120 parts (tensile strength ^{3 80kg / cm 2 (JIS K} -6301)) Amino-modified silicone oil, 1 part (KF867 represented by the following formula 8, Shin-Etsu 32 parts of polyisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd., solid content 75%) 847 parts of MEK

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Example 4 The ratio of the silicone-modified polyurethane resin (solid content: 20%) of the slip protective layer of Example 3 to polyisocyanate was 1: 1.
The reversible thermosensitive recording material of the present invention was prepared in the same manner as in Example 3 except that the ratio was changed to 2: 8.

[0035] Instead of a lubricous protective layer in Comparative Example 1 Example 1 The following ultraviolet crosslinking curing resin solution, and coating thickness 4 [mu] m, after coating and drying, 80 w / cm
Performs UV lamp curing process, except that a protective layer was formed to prepare a reversible thermosensitive recording material for comparison in the same manner as in Example 1. (Protective layer formulation) UV-crosslinkable curable resin urethane acrylate 10 parts (Dainippon Ink and Chemicals, Unidick C7-157 solid content 75%) Toluene 10 parts

[0036] The lubricous protective layer of Comparative Example 2 Example 2 substituting the following ultraviolet crosslinking curing resin solution, and coating thickness 2 [mu] m, after coating and drying, 80 w / cm
A reversible thermosensitive recording material for comparison was prepared in the same manner as in Example 2 except that a curing treatment was carried out with an ultraviolet lamp of No. 2 to form a protective layer. (Protective layer formulation) UV-crosslinkable curable resin urethane acrylate 10 parts (Dainippon Ink and Chemicals, Unidick C7-157) (solid content 75%) toluene 10 parts

The reversible thermosensitive recording materials obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated using a thermal head print tester manufactured by Yashiro Electric Co., Ltd. The thermal head used was a thermal head of 8 dots / mm from Ricoh Co., Ltd., with a platen pressing force of 1.0 kg and a pulse width of 1 m.
The test was performed with all solid printing under the conditions of s and a voltage of 25V.
Adhesion of scum to the thermal head was determined by an optical microscope, and image breakage and surface flaws were visually determined. The image deterioration is indicated by the difference between the first cloudiness density and the 100th cloudiness density. The density was measured with a Macbeth reflection densitometer (RD514). Table 1 shows the results.

[0038]

[Table 1]

[0039] Example 5 to about 100μm thick transparent on a polyester film (heat-sensitive layer Formulation) behenic acid 6 parts eicosanoic diacid 4 parts diisodecyl phthalate 3 parts chloride bi two Le - vinyl copolymer 25 parts of acetic acid (manufactured by UCC VYHH) A solution consisting of 180 parts of THF and 20 parts of toluene was applied with a wire bar and dried by heating .
A thermosensitive layer (reversible thermosensitive recording layer) having a thickness of about 15 μm was provided.
Further, a solution consisting of 10 parts of a polyamide resin (CM8000, manufactured by Toray Industries, Inc.) and 90 parts of methyl alcohol is applied by a wire bar, and dried by heating.
Then, an intermediate layer having a thickness of about 1.0 μm is provided, and a 75% butyl acetate solution of urethane acrylate ultraviolet curable resin (manufactured by Dainippon Ink and Chemicals, 10 parts Unidic C7-157) is further provided thereon. ) was uniformly dispersed liquid composed of 10 parts of toluene, was coated by a wire bar, heated drying, and cured at an ultraviolet lamp of 80W / cm, and a heat-sensitive member by providing a protective layer of about 5 [mu] m. Next, on the surface, an arbitrary pattern was printed by an offset printing method using a UV ink (for ultraviolet curing) and cured by an ultraviolet lamp to provide a printing layer having a thickness of 1.5 to 3.0 μm. Thereon (lubricous protective layer) silicone further - down-modified polyurethane resin (solid content 2 0%) 120 parts (tensile strength ^{380kg / cm 2 (JIS K-} 6301)) (25% elongation (JIS K-6301) ) A solution consisting of 848 parts of polyisocyanate (Coronate L 32 parts, manufactured by Nippon Polyurethane Industry Co., Ltd.-solid content 75%) MEK 848 parts is applied by a wire bar and dried by heating.
Then, a slip protection layer having a thickness of about 1.0 μm was provided. The resulting reversible thermosensitive recording material, further I row heat cured at 10 days dryer at 50 ° C., was prepared a reversible thermosensitive recording material of the present invention.

Example 6 The procedure of Example 5 was repeated, except that a lubricating protective layer solution according to the formulation of the lubricating protective layer of Example 3 was used in which an amino-modified silicone oil was added to the lubricating protective layer of Example 5. A reversible thermosensitive recording material of the invention was prepared.

Example 7 The ratio of the silicone-modified polyurethane resin (solid content: 20%) of the slip protective layer of Example 6 to polyisocyanate was 1: 1.
The reversible thermosensitive recording material of the present invention was prepared in the same manner as in Example 6 except that the ratio was changed to 2: 8.

Example 8 A reversible thermosensitive recording material of the present invention was prepared in the same manner as in Example 5 , except that the silicone-modified polyurethane resin of Example 5 was changed to the following components. (Prescription of slip protective layer) Silicone-modified polyurethane resin (solid content 20%) 120 parts (tensile strength 150 kg / cm ² , elongation 500% or more (JISK-6301) 32 parts polyisocyanate (Coronate L, Nippon Polyurethane Industry Co., Ltd.) ) Solidification 75%) 848 parts MEK

[0043] except for excluding the lubricous protective layer of Comparative Example 3 Example 5 to prepare a reversible thermosensitive recording material for comparison in the same manner as in Example 5.

[0044] The lubricous protective layer of Example 6 on the protective layer of Comparative Example 4 Example 5 provided, except that the printed layer is provided thereon, the reversible thermosensitive for comparison in the same manner as in Example 5 Recording material was created.

[0045] Example 5-8 was evaluated in the same manner as above for each reversible thermosensitive recording material obtained in Comparative Example 3-4. Further, regarding printability, the printing adhesiveness (JIS-K540)
8,5,2 foundation tape method) and printing glue in 0 (visual) was determined. The results are shown in Table 2 below.

[0046]

[Table 2]

[0047]

As is clear from the description of the examples and comparative examples, the reversible thermosensitive recording material of the present invention comprises an intermediate layer mainly composed of a heat-resistant resin, in particular, an ultraviolet-crosslinkable resin, and a silicone layer on the intermediate layer. A lubricating protective layer containing a crosslinked cured product of a modified polyurethane resin and a polyisocyanate, or a crosslinked cured product of an amino-modified silicone oil as a main component, and a silicone-modified polyurethane resin or amino-modified silicone on a printing layer By providing a lubricating layer containing a resin obtained by crosslinking and curing oil and polyisocyanate as a main component, the ruggedness with the thermal head is improved, and the surface is prevented from being scratched and the head residue is adhered, and the image is further prevented by the head residue adhesion. prevention of cut is possible. In addition, printability is improved by providing a slip protective layer on the print layer.
This has the effect of causing

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in transparency of a reversible thermosensitive recording material according to the present invention due to heat.

Continued on the front page (72) Inventor Makoto Kawaguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Toru Nogiwa 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Inside Ricoh (72) Kunichika Moroboshi 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Inside Ricoh (72) Inventor Fumito Masuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-63-221087 (JP, A) JP-A-63-317385 (JP, A) JP-A-1-1333781 (JP, A) JP-A-2-566 (JP, A) JP-A-3-180389 (JP, A) JP-A-3-24387 (JP, A) JP-A-5-139079 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/36

Claims (11)

(57) [Claims] 1. A heat-sensitive layer having a resin base material and an organic low-molecular substance dispersed in the resin base material as a main component and reversibly changing between a transparent state and a cloudy state depending on temperature on a support. In the reversible thermosensitive recording material provided with, an intermediate layer having a heat-resistant resin as a main component is provided on the heat-sensitive layer, and further, a crosslinked cured product of a silicone-modified polyurethane resin and a polyisocyanate is further formed thereon. A reversible thermosensitive recording material provided with a slip protective layer. 2. The reversible thermosensitive recording material according to claim 1, wherein the intermediate layer contains an ultraviolet curable resin as a main component. 3. The reversible thermosensitive recording material according to claim 1, wherein the lubricating protective layer mainly comprises a crosslinked cured product of a silicone-modified polyurethane resin, an amino-modified silicone oil and a polyisocyanate. 4. The reversible thermosensitive recording material according to claim 1, wherein the ratio of the polyisocyanate to the silicone-modified polyurethane resin is in the range of 6: 4 to 2: 8. 5. The silicone-modified polyurethane resin has a tensile strength (JIS K-6301) of 300 kg / cm.
5. The reversible thermosensitive recording material according to claim 1, wherein the elongation (JIS K-6301) is ² or more and 100% or less. 6. A heat-sensitive layer having, as a main component, a resin base material and an organic low-molecular substance dispersed in the resin base material, wherein a transparent state and a cloudy state are reversibly changed depending on temperature on a support. In the reversible thermosensitive recording material provided with, a printing layer is provided on the heat-sensitive layer, and a lubricating protective layer containing a crosslinked cured product of a silicone-modified polyurethane resin and a polyisocyanate as a main component is further provided thereon. A reversible thermosensitive recording material characterized by the following. 7. The reversible thermosensitive recording material according to claim 6, wherein an intermediate layer and a protective layer are sequentially provided between the thermosensitive layer and the printing layer. 8. The reversible thermosensitive recording material according to claim 7, wherein the intermediate layer contains an ultraviolet curable resin as a main component. 9. The reversible thermosensitive recording material according to claim 6, wherein the lubricating protective layer is mainly composed of a crosslinked cured product of a silicone-modified polyurethane resin, an amino-modified silicone oil and polyisocyanate. . 10. The reversible thermosensitive recording material according to claim 6, wherein the ratio of the polyisocyanate to the silicone-modified polyurethane resin is in the range of 6: 4 to 2: 8. 11. The silicone-modified polyurethane resin has a tensile strength (JIS K-6301) of 300 kg /
cm ² or more, elongation (JIS K-6301) 100%
The reversible thermosensitive recording material according to claim 6, 9 or 10, wherein: