JPS63218395A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To improve dye transfer properties, enhance performance of a heat- resistant slipping layer and contrive a thinner heat-resistant slipping layer, namely, a higher sensitivity of a thermal transfer sheet, by providing the heat- resistant slipping layer by using a reaction product obtained by a reaction of a thermoplastic resin comprising hydroxyl groups with an isocyanate in a specified ratio, a phosphoric acid ester surface active agent and a filler. CONSTITUTION:A thermoplastic resin comprising hydroxyl groups and an isocyanate are used in such a ratio that the equivalent ratio of isocyanate/ hydroxyl is 0.8-2.5. If the ratio is less than 0.8, a dye in a thermal transfer layer 2 migrates into a heat resistant slipping layer 4 upon close contact of the layers 2 and 4, resulting in poor preservability of a thermal transfer sheet. On the other hand, when the ratio exceeds 2.5, a sticking phenomenon occurs, leading to poor feedability of the thermal transfer sheet during recording. As the thermoplastic resin, polyvinyl butyral is particularly preferred because it reacts with the isocyanate to form a resin having favorable heat resistance. The isocyanate may be a polyisocyanate such as diisocyanate and triisocyanate, which may be used either singly or in combination.

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a thermal transfer sheet for performing thermal printing according to image information using a thermal head or the like, and more particularly to a thermal transfer sheet having an improved heat-resistant slip layer. K. PRIOR ART Conventionally, thermosensitive coloring paper has been mainly used to obtain an image according to image information using a thermal head. In these heat-sensitive coloring papers, a leuco dye, which is colorless or light-colored at room temperature, provided on a base paper and a color developer (eg, bisphenol A) contact and react with each other when heated, thereby producing a colored image. However, the above-mentioned thermosensitive coloring paper has a fatal drawback in that when the obtained image is stored for a long period of time, the color fades or the non-image area becomes colored. Furthermore, color printing is limited to two colors, making it impossible to obtain color images with continuous gradations. On the other hand, as a recording method to improve the above-mentioned drawbacks, a heat-melt transfer sheet in which a heat-melt wax layer in which a pigment or dye is dispersed is provided on a sheet-like substrate, or a heat-transferable dye contained in a binder is used. In recent years, thermal sublimation transfer sheets provided with a thermal sublimation transfer layer have begun to be used. This heat-melting transfer sheet and transfer sheet are overlapped,
When heating printing is performed from the back side of the heat-melting transfer sheet, the heat-melting wax layer containing the pigment or dye is transferred onto the heat-melting transfer sheet 1 to the top to form an image. According to this printing method, it is possible to obtain images that are more durable than thermal coloring paper, and multicolor images can be obtained by sequentially printing heat-melting transfer sheets containing pigments or dyes of the three primary colors. . On the other hand, a heat sublimation transfer sheet is formed by providing a single layer of a binder containing a heat-transferable dye on a sheet-like substrate, and then superposing the obtained heat sublimation transfer sheet and a heat sublimation transfer sheet to cover When thermal printing is performed from the back side of the thermal sublimation transfer sheet, only the dye in one layer of the binder is thermally sublimated and transferred onto the thermal sublimation transfer sheet to obtain an image. With this printing method as well, a multicolor image can be obtained by sequentially printing a heat sublimation transfer sheet containing heat transferable dyes of three primary colors. Incidentally, in recent years, there has been an increasing demand for obtaining images with continuous gradation, such as color photographs, directly from electrical signals, and various attempts have been made. The method using the heat sublimation transfer sheet described above is characterized in that the heat migratable dye in the heat sublimation transfer layer is transferred to the heat sublimation transfer sheet in response to the thermal energy applied to the heat sublimation transfer sheet. Therefore, images with continuous gradations can be obtained and can be recorded from television signals through simple processing. Condenser paper, polyester film, polypropylene film, cellophane, cellulose acetate film, etc. are conventionally used as the substrate for such thermal transfer sheets, and those having a thickness of about 10 μm are used. Among these substrates, condenser paper is selected from the viewpoint of price, but emphasis is placed on prevention of breakage during coating processing, ease of operation in the printer, uniformity of thickness, smoothness of the surface, etc. If this is the case, a plastic film is used, and among the plastic films, polyester film has been preferably used in view of its strength when used with tissue paper.

Problem to be solved by the invention When heating printing is performed with a thermal head from the base sheet, applying the energy necessary to obtain an image with sufficient print density to the back side of the film causes the base sheet itself to fuse with the thermal head, a so-called sticking phenomenon. If this occurs, the thermal sublimation transfer sheet may become unable to run, or in severe cases, the sheet may break at that location. In order to solve these problems, several attempts have been made to provide a heat-resistant protective layer on the back side of a base sheet in heat-melting transfer sheets. Some examples include a method of providing a gold R layer or a silicon oxide layer as an abrasion resistant layer on the back surface of the base (Japanese Unexamined Patent Publication Nos. 54-143152 and 57-74195), silicone, epoxy, etc. A method of providing a heat-resistant resin layer (Japanese Patent Laid-Open No. 57-74
No. 67), a method of providing a resin layer to which a solid or semi-solid W-surface active agent is added at room temperature (Japanese Patent Laid-Open No. 57-129)
78) or a method of providing a layer containing a lubricating inorganic pigment in a heat-resistant resin (Japanese Unexamined Patent Publication No. 155794/1983) has been proposed. When the heat-resistant protective layer proposed for these heat-melting transfer sheets was provided on the back side of the heat-sublimation transfer sheet to a thickness of about 3μ and printed using a thermal head, a sticking phenomenon was observed in all cases, indicating that it was sufficient. However, it could not function as a protective layer. The present inventors have studied various heat-resistant resins that can be used in thermal sublimation transfer sheets, as well as systems in which a slippery substance is added to the resins, and have found the following trends. In order to manufacture thermal sublimation transfer sheets with a heat-resistant protective layer through a manufacturing process such as coating, rather than through expensive processes such as vapor deposition, it is necessary to use a heat-resistant resin as a base. . Also 0,5~10μ
In order to prevent heat sensitivity from deteriorating for a polyester film of about 100 µm, the heat-resistant protective layer should have a thickness of about 0.5 to 3 μm.With a thickness within this range, the running of the thermal head on the heat sublimation transfer sheet is possible. To make this possible, it is necessary to add some lubricious substance to the resin base. However, if a heat-resistant protective layer is formed by adding a large amount of conventionally known inorganic substances such as talc and mica to the resin base, the running will not be smooth, solid printing will be rough, and the thermal head will become rough. This inorganic substance may adhere to. Further, since the thermal sublimation transfer sheet is generally stored by winding it up, the thermal sublimation transfer layer of the thermal sublimation transfer sheet and the back surface of the base sheet are in contact with each other. However, since the heat-resistant protective layer is provided on the back side of the base sheet as described above, conventionally known heat-resistant protective layers have the serious problem of dye present in the heat sublimation transfer layer migrating into the heat-resistant protective layer. A problem had arisen. Furthermore, with some types of heat sublimation transfer sheets, when the heat sublimation transfer sheet is transferred by a printing transfer device, etc., the heat sublimation transfer sheet and the rolls in the device may adhere to each other, causing the heat sublimation transfer sheet to Migration was sometimes an issue. Based on these experimental facts, the present inventors have determined that even when heated to high temperatures, the sticking phenomenon does not occur, the thermal head runs smoothly during recording, and it is possible to provide high-density images without roughness in the printed area. Moreover, we conducted research and development with the aim of obtaining a thermal transfer sheet that does not cause dye migration into the heat-resistant layer when it is rolled up and stored, and furthermore, does not cause the sheet to adhere to rolls, etc. in the transfer device. As a result, an application was filed as Japanese Patent Application No. 59-219183. That is, the thermal transfer sheet according to the invention has a thermal transfer layer on one side of a base sheet, and a heat-resistant layer formed by curing a synthetic resin that can be cured by heating with a curing agent, and a polyvinyl butyral layer on the other side. A heat-resistant slip layer consisting of a reaction product of isocyanates, an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester, and a filler are laminated in this order. By using such a thermal transfer sheet, we achieved the above objectives and developed a thermal transfer sheet that can be used as a thermal sublimation transfer sheet. It was possible to further improve the properties of the heat-resistant slip layer, that is, the dye migration property, and to enhance the performance of the heat-resistant slip layer, and also to make the heat-resistant slip layer thinner, that is, to increase the sensitivity of the thermal transfer sheet. Means for Solving Problem K] The present invention provides a thermal transfer sheet that has a thermal transfer layer on one surface of a base sheet and a heat-resistant slip layer on the other surface of the base sheet that is in contact with a thermal head. , a reaction product obtained by using the heat-resistant slip layer with a thermoplastic resin containing a hydroxyl group and isocyanates in a ratio such that the equivalent ratio of isocyanate group/hydroxyl group is 0.8 to 2.5, a phosphoric acid ester interface. The present invention relates to a thermal transfer sheet formed from an activator and a filler. To explain the structure of the thermal transfer sheet of the present invention with reference to the drawings, a thermal transfer layer 2 made of a binder and a dye that is transferred by melting or sublimation by heating is provided on a base sheet 1, and the other side of the base sheet 1 is coated with the necessary materials. A heat-resistant layer 3 is provided according to the
Further, a heat-resistant slip layer 4 is provided on the surface in contact with the thermal head. The present invention is characterized in that a heat-resistant slip layer is formed from a resin product, a surfactant, and a filler obtained by blending a heat-resistant slip layer in a specific blending ratio. sheet, thermal transfer layer. Each heat-resistant layer will be explained in detail. 11 The heat-resistant slip layer 4 has a suitable level of lubricity (
It is extremely important for improving the running properties of the sheet by imparting smoothness (sliding) and preventing thermal adhesion (sticking phenomenon) between the thermal head and the thermal transfer sheet. The heat-resistant slip layer according to the present invention includes (a) a reaction product formed by using a thermoplastic resin containing a hydroxyl group and isocyanates in a specific ratio, (b) a phosphate ester surfactant,
and (iii) a layer mainly composed of a filler. Thermoplastic resins containing hydroxyl groups include polyvinyl butyral, polyvinyl acetal, polyvinyl formal,
Examples include polyester polyols, acrylic polyols, polyether polyols, urethane polyols, and polyesters, but polyvinyl butyral is preferably used. Thermoplastic resins containing hydroxyl groups, particularly polyvinyl butyral, react with isocyanates to form resins with good heat resistance. The polyvinyl butyral preferably has as high a molecular weight as possible and contains as much 10H% as reaction sites with isocyanates. Among polyvinyl butyral, particularly preferred is polyvinyl butyral with a molecular weight of eo
, ooo~200°000, glass transition temperature 60~1
At 30°C, the lff1% of the vinyl alcohol portion contained is 15 to 40%. Isocyanates used in forming the heat-resistant slip layer include polyisocyanates such as diisocyanate and triisocyanate, which may be used alone or in combination. Specifically, the following compounds are exemplified. Para-phenylene diisocyanate, 1-chloro-2゜4-phenyl diisocyanate, 2-chloro-1゜4-phenyl diisocyanate, 2,4-toluene diisocyanate,
2.6-Toluene diisocyanate, hexamethylene diisocyanate, 4゜4'-biphenylene diisocyanate, triphenylmethane triisocyanate, 4.4
',4''-trimethyl-3,3',2'-triisocyanate-2,4,6-1-rife nyl cyanurate, adducts such as propylene glycol and tolylene diisocyanate, biuret type In the present invention, in particular, the thermoplastic resin containing a hydroxyl group and the isocyanate-1. If this ratio is less than 0.8, if the thermal transfer layer and the heat-resistant slip layer come into close contact, the dye in the thermal transfer layer will migrate into the heat-resistant slip layer, resulting in poor storage stability of the thermal transfer sheet. On the other hand, if the ratio exceeds 2.5, a sticking phenomenon will occur and the running properties of the thermal transfer sheet during printing will deteriorate, which is undesirable. The resin used as a resin has a molecular weight of at least 2 in order to have excellent heat resistance and form a flexible film after the curing reaction.
It needs to be 0,000 or more. OH in resin
The content of the group affects the crosslinking density and heat resistance, but since the required amount differs depending on the type of resin, it is selected and determined as appropriate. Next, as for the phosphate ester surfactant, it is desirable to use both an acid type and a salt type. When a thermal transfer sheet having a heat-resistant slip layer is transferred inside a printing transfer device, for example, problems may arise in the transferability of the thermal transfer sheet depending on the tension applied to the thermal transfer sheet or the printing pressure of a thermal head. Acid-type activators have excellent transferability for thermal transfer sheets, but
The larger the amount added, the more the dye will migrate from the dye layer to the heat-resistant slip layer when stored in a rolled state. On the other hand, in the presence of a salt-type activator, the reaction between the thermoplastic resin containing hydroxyl groups and isocyanates proceeds rapidly,
Moreover, the degree of crosslinking is increased, and the dye in the thermal transfer layer does not migrate into the heat-resistant slip layer, but if only the salt type is used, there is a problem in the transferability of the thermal transfer sheet. Therefore, in order to have no problems with transferability and to minimize dye transfer, it is necessary to use both in combination. The mixing ratio of the acid type activator and the salt type activator is 10 to 50% by weight of the salt type activator based on the resin, and 20 to 120% of the acid type activator based on the resin, although it varies depending on the amount of curing agent added. Use at a heavy weight ratio of %. The salt-type phosphate ester surfactant is used to impart lubricity to the heat-resistant slip layer, and Gaff 1 Tsuku RD 720 (trade name) manufactured by Toho Chemical Industry @J is used. Alkali metal salts or alkaline earth gold a salts of phosphate esters are added as lubricants in a molecularly dissolved state in the binder, so they are different from the case where solid lubricants such as mica or talc are added. In comparison, there is an advantage that no roughness occurs in the printed area. As the alkali metal salt or alkaline earth metal salt of the phosphoric acid ester, a natrilam salt of the phosphoric acid ester is particularly preferred, and an example thereof is shown by the following general formula. (In the formula, R is an alkyl group or alkylphenyl group having 8 to 30 carbon atoms, and n is the average number of added moles of ethylene oxide.) In addition, as the acid type phosphate ester activator, the aforementioned phosphorus Acid esters that are not in the form of alkali metal salts or alkaline earth metal salts of phosphoric acid esters are used, specifically, Blysurf^2088 (trade name) manufactured by Daiichi Kogyo Seiyaku ■; Gafac R3710 (trade name) manufactured by Toho Chemical Industry@ is used. Fillers added to the heat-resistant slip layer include clay,
Inorganic or heat-resistant paid fillers such as talc, zeolite, aluminosilicate, calcium carbonate, Teflon powder, zinc Mide, titanium Mide, magnesium oxide, silica, carbon, and a condensate of benzoguanamine and formaldehyde are used. . The average particle size of this filler is 3 μm or less, preferably 0.1
It is desirable that the thickness is 2 μm. The filler is used in an amount of 5 to 60% by weight, preferably 10 to 40% by weight, based on the thermoplastic resin containing hydroxyl groups. By using such a filler in the heat-resistant slip layer, the fusion between the thermal head and the thermal transfer sheet is reduced, and the so-called sticking phenomenon is completely eliminated. To provide the heat-resistant slip layer on the base sheet 1, the above-mentioned components are dissolved in an appropriate solvent to form an ink for forming the heat-resistant slip layer, and this is printed using an appropriate printing method. It is formed on the base sheet 2 by a coating method, and then 30~
By heating to a temperature of 80° C., the polyvinyl butyral and isocyanates are reacted while drying to form a heat-resistant protective film. At this time, it is preferable to prepare a filler cross-dispersion composition by kneading the filler in advance with an alkali metal salt or an alkaline earth metal salt of a phosphoric acid ester. The heat-resistant slip layer has a thickness of 0.5 to 5 μm, preferably 1 to 5 μm.
It is preferable to have a film thickness of 2 μm. This film thickness is 0.
When it is thinner than 5 μm, the effect as a heat-resistant slip layer is not sufficient, and when it is thicker than 5 μm, there is a disadvantage that heat transfer from the thermal head to the sublimation transfer layer becomes poor and print density becomes low. Base material sheet Base material sheet 1 is a condenser paper. Polyester film, polyethylene naphthalate film, polystyrene film, polysulfone film, polyimide film, polyvinyl alcohol film, cellophane, aramid (aromatic polyamide), polyphenylene sulfide. Plastic films such as polyetheretherketone and polyethersulfone are used, and the thickness is 2.
~50 μm, preferably 2-12 μm. These plastic films are preferred because they have a smooth surface and high mechanical strength, and among them, polyester films and aramid films are preferably used. In accordance with the gist of the invention, the base sheet is mainly a plastic film, but in addition to this, paper such as condenser vapor is also used when the price of the sheet itself and the heat resistance of the sheet itself are important. can. Thermal Transfer Layer The thermal transfer layer 2 is composed of a dye that melts or sublimates and transfers when heated, and a binder. The dye is preferably a sublimable disperse dye, a sublimable oil-soluble dye, or a sublimable basic dye, and has a molecular weight of 1.
50-800. Preferably it is 350-700. These dyes have a sublimation temperature of 2 hues and are weather resistant. They are selected in consideration of solubility in the ink or binder resin, and are selected, for example, as follows. C, 1, (abbreviation of color index, same below) Yellow 51. Same 3. Same 54. Same 79° Same 60. Same 23. Same 7. 141, c, i, disperse blue 24. 56. 14゜301. 334. 165. Same 19. Same 72. Same 87
゜Same 287. 154. 26, C, 1, Dispersed Thread 135. 146. Same 59
, same 1. Same 73. 60. 167, c, i, disperse violet 4. Same 13° Same 36. 56. 31
, C,1, Solvent Violet 13, C,1, Solvent Black 3, C,1, Solvent Green 3, C,1, Turben 1 to Yellow 56. Same 14. Same 16° Same 29, C, 1, Solvent Blue 0. 35. Same 63. Same 3
6, same 50. 49. Same 111. Same 1o5. 97. Same 11, C, 1, Solvent Red 135. 81. Same 1
8゜same 25. Same 19. Same 23. Same 24. 143. Same 1
46. The binders for the 182° thermal transfer layer include ethylcellulose, droxyethylcellulose, ethylhydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, and cellulose acetate. Cellulose resins such as cellulose acetate butyrate, polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyester, polyvinyl acetate. Vinyl resins such as polyacrylamide can be used. As an example of a more preferable binder, instead of the above-mentioned ordinary vinyl butyral resin, a binder having a molecular weight of 60.000 to 60.000 is used.
200.000, the weight percent of the vinyl alcohol moiety in the polyvinyl butyral resin is 10-40%, preferably 15
-30%, and a special polyvinyl butyral resin with a glass transition temperature of 60-130°C, preferably 70-130°C. If the glass transition point is less than 60°C, the dye will aggregate or precipitate over time, whereas if it exceeds 130°C, the dye will not sublimate sufficiently, which is not preferred. If the molecular weight is less than 60,000, the cohesive force as a binder is insufficient, and if it exceeds 200,000, the viscosity during coating becomes too high, causing problems in coating. If the vinyl alcohol content is less than 10%, the stability of the thermal transfer layer over time will be insufficient, so that aggregation, precipitation, and bleeding of the dye onto the surface cannot be avoided. On the other hand, if it exceeds 40%, the affinity of the polyvinyl alcohol portion for the dye prevents sublimation of the dye, resulting in a decrease in printing density. Regarding the weight of the dye and binder in the thermal transfer layer, it is desirable that the dye/binder ratio is 0.3 or more, and if it is less than 0.3, the printing density and thermal sensitivity will be insufficient. Furthermore, if the ratio of dye/binder exceeds 2.3, the retention of the dye in the binder becomes insufficient and the storage stability of the thermal transfer sheet deteriorates. Therefore, the dye/binder is 0.3
It is preferable that it is ~2.3, more preferably 0.5
5 to 1.5. Preferably, the dye is dissolved in the binder of the thermal transfer layer. In conventional sublimation transfer paper for textiles, the dye is dispersed in a binder, so in order to sublimate the dye, it is necessary to provide energy that overcomes the interactions between dye molecules and the interactions between dye molecules and the binder. , which necessarily requires high energy, resulting in reduced thermal sensitivity. In this respect, it is advantageous in terms of heat sensitivity if the dye is dissolved in the binder. It goes without saying that the thermal transfer sheet of the present invention is also applicable to those having a heat-fusible thermal transfer layer, and the heat-fusible transfer layer will be explained next. The heat-melting transfer layer consists of a binder and a colorant that melt when heated. Binders include wax, drying oil, and resin. Mineral oils, cellulose and rubber derivatives, etc., and mixtures thereof are used. As the binder wax, microcrystalline wax, carnauba wax, and paraffin wax are preferably used, and in addition to these, Fisch 17-h Robusch wax, various low molecular weight polyethylenes, some modified waxes, fatty acid esters, amides, and real waxes are used. Various waxes can be used, such as beeswax, spermaceti wax, firefly wax, wool wax, shellac wax, candelilla wax, and petrolatum. Examples of the binder resin include ethylene vinyl acetate, ethylene ethyl acetate, polyethylene, polypropylene, polybutene, petroleum resin, vinyl chloride resin, and polyvinyl alcohol. Vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl fluoride, polyvinyl butyral, acetylcellulose, nitrocellulose, vinyl acetate resin. Polyisobutylene, polyacetal, or the like can be used. The colorant may be an organic or natural pigment or dye that has good properties as a recording material, such as one that has sufficient color density and is transparent to light. Preferably, it does not change color or fade due to heat or humidity. Since the coloring agent is used for the purpose of coloring the binder of the heat-melting transfer layer, it is not preferable to use a coloring agent that melts when heated. The hot-melt transfer layer is made into a hot-melt ink by melting and mixing the above-mentioned binder and colorant, and in addition to hot-melt coating on a sheet-like base material, it can also be coated with a conventional printing or coating method, or by a specific method. can be applied by methods such as hot lacquer coating, gravure reverse coating, roll coating, gravure printing, barcode, etc.
The thickness is usually 0.1-30μ, preferably 1-20μ. For the thermal transfer layer, a dye is selected so that a desired hue can be transferred when printing, and if necessary, two pairs of thermal transfer layers with different dyes may be arranged side by side on one thermal transfer sheet. For example, when printing each color repeatedly according to the color separation signal to form an image such as a natural color photograph, it is desirable that the hues of the print are cyan, magenta, and yellow. Three thermal transfer layers containing dyes that give . Or cyan. A thermal transfer layer containing a dye giving a black hue in addition to magenta and yellow may be added. Incidentally, it is preferable to provide marks for position detection at the same time as the formation of any of the thermal transfer layers, since no ink or printing process separate from the formation of the thermal transfer layer is required. Heat Resistant Layer It is preferable to provide the heat resistant layer 3 separately from the heat resistant slip layer 4 described above in order to improve the heat resistance of the thermal transfer sheet. Several types of combinations can be used as the heat-curable synthetic resin and its curing agent, which constitute the heat-resistant layer. Typical examples are polyvinyl butyral and polyvalent isocyanate, acrylic polyol and polyvalent isocyanate, cellulose acetate and titanium chelating agent, and polyester and paid titanium compound. The following table shows the names of products and the amounts (parts by weight) that should be added, including those that are easily available on the market. Below is the margin ■ Synthetic resin that can be cured by heating Amount 1
Polyvinyl butyral “S-LEC BX-IJ (Kenzu Kagaku> 100
Part 2 Urethane polyol rDF30-55” (large book ink) 1003
Urethane polyol rDF30-55JA-801-P
J (Dainippon Ink) 1005 Polyester "Byron 2004"(Toyobo>-io. 6 Polyester "Byron 200"(Toyobo> 1007)
Polyester r-by-Don 200J (Toyobo> 100
8 Polyester “Byron 200J (Toyobo) 1009
Cellulose acetate rL20J (Vercules) 1001
o Cellulose acetate rL20J (Vercules > 100
11 Nitrocellulose [Nidocello 5S74J (Daicel) 20-50
12 Chlorinated rubber rcR-10J (Asahi Denka) 100
13 Chlorinated rubber rCR-10J (Asahi Denka) 1001
4 Melamine "Melan 45" (Hitachi Chemical> 100 Hardening agent formulation amount Diisocyanate "Takenate D11ONj (Narita Pharmaceutical) 45
Polyisocyanate "Burnock D-750J (Dainippon Ink) 20 Polyisocyanate [Parnock D-750J (Dainippon Ink> 2
0 Polyisocyanate “Parnock D-750J (Dainippon Ink> 2
0 Polyisocyanate “Parnock D-750” (Dainippon Ink> 20
Titanium chelating agent “Titabond 50” (Nippon Soda) 5~
10 Organic titanium compound rA-10j (Nippon Soda) 10 Organic titanium compound rB-10J (Nippon Soda) 1
0 Titanium chelating agent “Titabond 5D” (Nippon Soda) 5 Polyisocyanate “Parnock D-7504 (Dainippon Ink) 10 Polyisocyanate [Parnock D-750J (Dainippon Ink)> 5
0 to 20 Polyisocyanate [Parnock D-750J (Dainippon Ink) 30 Yukou Titanium Compound rB-10J 1° Para-toluenesulfonic acid 2° It may be preferable to add an extender pigment to the above synthetic resin. Examples of extender pigments suitable for this purpose are magnesium carbonate, calcium carbonate, silica, clay, titanium Mide and zinc oxide. The appropriate amount is usually 5 to 40% of the resin based on weight. For addition and mixing, it is preferable to use a three-roll mill or a sand mill to achieve sufficient dispersion. If the adhesive strength of the heat-resistant layer to the base film is insufficient, it is advisable to use an appropriate brimer. By the way, generally, the component that imparts lubricity (slip) to the sheet surface and the component that imparts heat resistance tend to cancel each other out. For example, in the heat-resistant slip layer 4, when the slipping component is increased, the heat resistance decreases. Therefore, in order to obtain good heat resistance, the thickness of the heat-resistant slip layer must be increased. In order to avoid this problem, it is preferable to provide the heat-resistant layer 3 and the heat-resistant slip layer 4 in a laminated manner.By adopting such a structure, both slipperiness and heat resistance can be improved at the same time. At the same time, the film thickness can be reduced as a result. A thermal transfer layer 2 is formed on the base sheet 1. The order in which the heat-resistant layer 3 and the heat-resistant slip layer 4 are provided is preferably heated to promote the reaction between polyvinyl butyral and isocyanate, and in order to prevent the thermal transfer layer from being affected by heat during this heating, After providing the heat-resistant slip layer 4 on the base sheet 2, it is preferable to provide the thermal transfer layer 2 next. K Examples] Example 1 An ink composition for a heat-resistant slip layer having the composition shown below (parts by weight) was prepared, and a polyester film (trade name: "
The ink composition was applied onto Lumirror (manufactured by Toshi ■) using Myabah #8 at a coating weight of 1 Og/m, and then dried with warm air. Ink composition for heat-resistant slip layer (I) Polyvinyl butyral resin ([S-LEC BX-1J, manufactured by Block Chemical Co., Ltd.] 2.2Φ hanging part Toluene 35.4 parts by weight Methyl ethyl chemistry 53.0 parts by weight Isocyanate ("Parnock D") -750J Dainippon Ink Chemical @J) 6.8 parts by weight phosphate ester (Plysurf A-208SJ manufactured by Daiichi Kogyo Seiyaku ■) 1.6 parts by weight phosphoric ester, 1 helium salt (1 Gaff RD720 J manufactured by Toho Chemical Industry @) 0.6 parts by weight Talc (Micro Ace [-1 manufactured by Nippon Talc ■) 0.41 parts Amine catalyst (DesmoRapid PPJ manufactured by Sumitomo Bayer Urethane ■) 0.02 parts by weight The obtained film was further heated at 60°C for three days in an oven for curing treatment.The ratio of isocyanate/thermoplastic resin having hydroxyl groups in the above ink composition for heat-resistant slip layer was 1.8. Separately, yellow, magenta, and cyan ink compositions for forming heat sublimation transfer layers having the following compositions were prepared, and each was coated with Myaber #10 on the base film surface opposite to the heat-resistant slip layer. The coating amount of each of these transfer layers was about 1.0 g/Tlt. Ink composition for forming thermal sublimation transfer layer ◎ Yellow disperse dye (Disperse Yellow 119)
) 3.0 parts by weight Polyvinyl butyral (manufactured by S-LEC BX-IJ Sekisui Chemical) 4.3 parts Toluene 46.01 parts Methyl ethyl ketone 46.7 parts by weight Magenta disperse dye (Disperse Red Go)
2.6 parts by weight polyvinyl butyral (“XS L/Tsuku BX-1” Water Chemistry @￥J) 46.
Pentaite part methyl ethyl ketone 46.6
Part by weight ◎Cyan oil-soluble dye (Solvent Blue 63)
4 mm part polyvinyl butyral ("S-LEC BX-IJ Sekisui Chemical it [> 4.3
Heavy ffi part toluene 45.
0 parts by weight methyl ethyl ketone 46.7
Parts by weight Next, the image receiving paper will be explained. 150μ thick synthetic paper “YIJP” is used as a base film.
O-FPG150 j (manufactured by Ni7 Yuka v/J) For use, apply ink for forming an image receiving layer with the following composition using a wire bar #36 so that the dry coating amount is 4.0 g/TIt. This was used as a thermal transfer sheet. Ink for forming image-receiving layer Polyester resin ([Vylon 200J, manufactured by Toyobo @) 5 parts by weight Polyester tI4 resin ([Vylon 290J, manufactured by Toyobo @) 5 parts by weight Amine-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 parts by weight Epoxy-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 parts Ichibe l/Luene 44.5 parts Methyl ethyl ketone 44.511 parts The heat sublimation transfer sheet obtained as above and the heat transfer sheet were thermally transferred. The layers were stacked so that they were in contact with each other, and recording was performed using a thermal head from the heat-resistant slip layer side. The recording conditions were: power output 0.26W/dot, pulse width: 1.0-16.0m5ec, drum 1-density:
6 dots/m#l. There was no sticking phenomenon or wrinkles, and the heat-sensitive transfer film obtained as described above ran smoothly. Next, a dye migration test was conducted. Film coated with heat-resistant slip layer and yellow, magenta. The films coated with the cyan dye layer were stacked on top of each other and left for three days at 60° C. under a load of 17 g per cm. The increase in color density on the heat-resistant slip layer side after three days (○, D) was determined by measuring using a Macbeth color densitometer RD-918. As a result, 80.D.
is yellow: 0.01, magenta: O, OS
, cyan: 0.06, which was extremely small, and the dye transfer was hardly noticeable in appearance. In addition, print recording was performed using the thermal transfer film after the dye migration test l~ as described above, but the print density of the heat sublimation transfer layer after the test was the same as that of the film before the test. No decrease in print density was observed compared to when recording was performed. Furthermore, the thermal transfer sheet according to the present invention obtained as described above has a heat-resistant slip layer ink composition necessary for smooth conveyance without wrinkles when printing under the above-mentioned recording conditions. As a result of considering the amount of application, 0.5g
/Go turned out to be sufficient. When the coating amount of the ink composition is 3.0 g/rd, in order to obtain a printing density of 1.0 with the heat sublimation transfer layer containing the cyan dye, it is necessary to apply 2.4 m J/rd.
Dot printing energy is required, but if the coating amount of the heat-resistant slip layer is 0.5g/TIt, it is 1.67FL.
J/' dot is sufficient, reducing printing energy by about 33%
Can be reduced. Example 2 The following composition (ff>
A thermal transfer film was formed in the same manner as in Example 1, except for changing to . Ink composition for heat-resistant slip layer (II) Polyvinyl butyral resin ("S-LEC BX-1", manufactured by Building Block Chemical @ J) 3.0 Parts by weight 1 - Luene 44.53 Parts by weight Methyl ethyl ketone 44.53 Parts by weight ff
I part isocyanate (“Parnock D-750J. Dainippon Ink Chemical @￥J> 4.2 f
flfffl part phosphate ester ("Plysurf^-208SJ" manufactured by Daiichi Kogyo Seiyaku@J) 2.2 parts by weight phosphate ester sodium salt ("GAF8C RD720 J" manufactured by Toho Chemical Industry ■) 0.9 Part by weight Talc ([Micro Ace L-IJ, manufactured by Nippon Talc Ltd.) 0.6 Part by weight Amine catalyst (Desmoravit PPJ, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 0.04 parts by weight Isocyanate-1 in the above composition - The equivalent ratio of groups/hydroxyl groups was 0.8. When the obtained thermal transfer film was printed under the same conditions as in Example 1, no sticking dyeing or wrinkles were observed. The dye migration test was carried out in the same manner as in Example 1, and △O, D were yellow: 0.03, magenta: 0.35, cyan: 0.32, and the appearance was heat-resistant slip. Dye migration to the layer side was observed, the heat-resistant slip layer and the thermal transfer layer were blocked, and when printing was recorded on the thermal transfer film after the test, the printing density of the thermal sublimation transfer layer after the test was the magenta,
When a thermal transfer layer containing cyan as a dye was used, the print density decreased by 20 to 30%. Example 3 An ink composition for a heat-resistant slip layer was prepared using the following composition <I[[
) A thermal transfer sheet was formed in the same manner as in Example 1 except that Ink composition for heat-resistant slip layer (III) Polyvinyl butyral resin ([S-LEC BX-IJ, currently out of stock at Building Blocks Chemical Co., Ltd.] 1.8 1 m part Toluene 44.04 Overlapping parts Methyl ethyl carbonate 44.04 Overlapping parts isocyanate ("Parnock") D-750J. Manufactured by Dainippon Ink Chemical @7.9 Parts by weight Phosphate ester ([Blysurf A-208SJ. Daiichi Kogyo Seiyaku (Closed)) 1.3 Parts by weight Phosphate ester, sl-lium salt ( rGAFACRD720 J. Manufactured by Toho Chemical Industry Co., Ltd.) 0.54-heavy part talc (Micro Ace L-I J. Nippon Talc (manufactured by Taiho) 0.36-width hanging part amine catalyst ([Desmo Pit 1-PPJ. Sumitomo Bayer Urethane fIJ) Made > 0.02
1 part The equivalent ratio of isocyanate groups to hydroxyl groups in the above composition was 2.5. When printing was carried out on the thermal transfer film prepared under the same conditions as in Example 1, a sticking phenomenon was observed when the pulse width was short, but no wrinkles were observed. Next, a dye migration test was conducted in the same manner as in Example 1, and 80, D, yellow: o, oi. Magenta: 0.06, cyan: 0.05, and no dye migration toward the heat-resistant slip layer was observed in appearance. IR spec of the film surface coated with the heat-resistant slip layer of the thermal transfer film obtained as above]
When measuring L, an absorption based on NGO groups was observed near 2272 cm-', and from the magnitude of this absorption, it seems that there is a considerable amount of residual isocyanate. When the amount of residual isocyanate increases as described above, there is a possibility that the various properties of the thermal transfer film may change due to the reaction between the moisture in the air and the residual isocyanate when stored at high temperatures. Example 4 Example except that before forming a heat-resistant slip layer on a polyester film, a heat-resistant layer was formed using an ink composition for a heat-resistant layer having the following composition, and then a heat-resistant slip layer was formed on the heat-resistant layer. A thermal transfer film was produced in the same manner as in Example 1. Ink composition for heat-resistant layer Acrylic polyol (“Acrit 6416148” 45% solution, manufactured by Taisei Kako ■) 41.2 parts by weight Toluene 2f3.3ffi
Foot methyl ethyl ketone 26.3 hand f
fi part Diisocyanate ("Coronate" 45% acetate ester solution 9 parts polyurethane @ J product) 6.2 parts by weight The above composition was coated on a polyester film using Myabah #8 in an amount of 1.5 g/rd. After applying as follows,
Dry with warm air. A heat-resistant slip layer was provided on the heat-resistant layer in the same manner as in Example 1, and an ink for forming a thermal sublimation transfer layer was applied to the opposite side of the polyester film. The dye migration property of the rolled thermal transfer film was not affected by the provision of the heat-resistant layer as described above (the same results as with the heat-resistant slip layer in Example 1 were obtained). In addition, when we conducted a printing test using a printer, we found that with the thermal transfer film of Example 1, which does not have a heat-resistant layer, when the printing energy exceeds 6 iJ/dot, the film stretches due to heat and wrinkles occur, leaving marks on the printing surface. However, in the thermal transfer film according to this example provided with a heat-resistant layer, it is 6 mJ/
Even when dot printing energy was applied, no wrinkles were observed. Example 5 A heat-resistant slip layer ink composition (1■) having the following composition was prepared and coated on a 4.5μ thick polyester film (trade name "Lumirror", manufactured by Toshi@) using Myabar #10. The ink composition was applied to a coating amount of 1.5 cm/cri, and then dried with warm air. Heat-resistant slip opening ink composition (TV) Acrylic polyol (Acrit 6455HAJ 45% solution manufactured by Taisei Kako ■> 24.7 parts by weight Isocyanate (Coronate [45% solution manufactured by Nippon Polyurethane ■) 7.4 parts by weight Methyl ethyl ketone 62.4 double base phosphate ester (Pricesurf 8-208SJ, manufactured by Dai-Kogyo Seiyaku Aji) 3.31 Dobe phosphate ester, sl, lithium salt (GAFAc RD720 J, manufactured by Toho Chemical Industry ■) 2.2 parts by weight of the obtained film was further heated in an oven at 60°C for 2 hours to perform a curing treatment. The equivalence ratio was 1.0. A thermal transfer film was obtained by providing a thermal sublimation transfer layer on the opposite side of the polyester film in the same manner as described in Example 1. In addition, the thermal transfer sheet described in Example 1 was Printing was carried out under the same conditions as in Example 1. No sticking or wrinkles were observed, and smooth running was possible. When a test was conducted using the same method as in 1, it was found that the color density increased due to dye migration onto the heat-resistant slip layer △O,
D, yellow: 0.02, magenta = 0.09
, cyan: 0.09, and in terms of appearance, almost no dye migration was observed.

【Effect of the invention】

The thermal transfer sheet according to the present invention has improved heat resistance and a heat-resistant slip layer by increasing the equivalent ratio of isocyanate groups/hydroxyl groups of the thermoplastic resin containing hydroxyl groups and isocyanates that form the heat-resistant slip layer. Even if the layer and the thermal transfer layer are brought into close contact with each other, the dye does not migrate to the heat-resistant slip layer, and the storage stability of the thermal transfer sheet is improved. In addition, the improvement in heat resistance can be achieved by reducing the coating amount of the ink composition constituting the heat-resistant slip layer to about 2.5 to 3.0% compared to the conventional one when using a 4.5μ polyethylene film as the base material.
y/rrl to 0.5 to 1.0 g/m, and therefore the energy required to obtain the same print density is 10 to 1.0 g/m.
It can be reduced by 30%. Furthermore, in the present invention, the phosphate ester surfactant added to the heat-resistant slip layer prevents the occurrence of sticking phenomenon and improves the running properties of the transfer sheet during printing. Even if high-density solid printing is performed at 10.000771, there is no effect on the printed surface, and it has extremely excellent long-run suitability.

[Brief explanation of the drawing]

The accompanying drawing is an enlarged sectional view of a thermal transfer sheet according to the present invention. 1...Base material sheet, 2...Thermal transfer layer.

Claims (1)

[Claims] 1. In a thermal transfer sheet comprising a thermal transfer layer on one side of a base sheet and a heat-resistant slip layer on the other side of the base sheet in contact with the thermal head, the heat-resistant slip layer is a thermal transfer layer containing a hydroxyl group. The equivalent ratio of isocyanate group/hydroxyl group is 0.8 to 2.5 between the plastic resin and the isocyanate.
1. A thermal transfer sheet comprising a reaction product obtained by using the following proportions, a phosphoric acid ester surfactant, and a filler.