JPH0829622B2 - Sheet for thermal transfer recording - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The thermal transfer recording sheet of the present invention is used for color recording of OA terminals such as facsimiles, printers, copiers, etc., which have been rapidly spreading in recent years, and for color recording of television images. Etc. can be advantageously used.

[Conventional technology]

Various methods such as electrophotography, ink jet, and thermal transfer recording have been studied for color recording in the above-mentioned OA terminal or color recording of television images. It is advantageous over other methods in that it is easy and the device is small and inexpensive.

In this thermal transfer recording method, an image receiving body is superimposed on the ink-coated surface of a thermal transfer recording sheet in which ink containing a coloring material is applied on a base film, and the back surface of the thermal transfer recording sheet is heated with a thermal head. Recording is performed by transferring the color material in the sheet to the image receiving body.

Such a thermal transfer recording system includes a thermal transfer recording system using a thermal transfer recording sheet coated with a hot-melt ink, and a sublimation thermal transfer recording system using a thermal transfer recording sheet coated with an ink containing a sublimable dye. There is.

When recording with this method, the thermal transfer recording sheet is conveyed while being heated by the thermal head, so if the heat resistance and lubricity of the base film are insufficient, the base film will melt and cause a sticking phenomenon with the thermal head. As a result, the sheet cannot be conveyed and recording cannot be performed, or dust is attached to the head to deteriorate the image quality of recording.

As the base film, polyethylene terephthalate film is advantageous because it is economical and has good mechanical strength, but it cannot be used as the base film for this purpose as it is because of insufficient heat resistance and lubricity.

Conventionally, in order to improve the heat resistance and lubricity of a thermal transfer recording sheet, in the case of a sheet of a fusion type thermal transfer recording system,
The base film may be provided with various heat-resistant resin protective layers (JP-A-55-7467 and JP-A-57-74195), and inorganic pigments, surfactants and heat-melting substances may be added to the heat-resistant resin protective layer. And the like (JP-A-55-14670, JP-A-56-1)
55794, JP-A-57-129789). However, recently, in the recording system of this system, a thermal transfer recording sheet having better heat resistance is required for heating the thermal head to a higher temperature than in the past in order to increase the recording speed. Further, the sublimation type thermal transfer recording method requires higher energy than that of the melting type thermal transfer recording method, so that the sheet used for the same is required to have higher heat resistance. The proposed one is insufficient for these requirements.

In order to improve the heat resistance of a thermal transfer recording sheet for sublimation type thermal transfer recording, a method using a photo-cured product of an oligoacrylate or a photo-cured product of an epoxy resin as a heat-resistant protective layer of a base film (JP-A-59) -196291, JP-A-60-71
292), a method using a cured product of polyvinyl butyral and isocyanates (JP-A-60-184883), a method using a cured product of an organometallic compound such as a silicone resin (JP-A-60-230896), and the like. However, since each requires a resin curing step to form a heat-resistant protective layer,
The manufacturing process becomes complicated.

[Problems to be solved by the invention]

An object of the present invention is to provide a thermal transfer recording sheet which does not cause a sticking phenomenon with the thermal head even at the time of recording with high energy and has no dust attached to the thermal head, and which is easy to manufacture.

[Means for solving problems]

That is, the present invention provides a thermal transfer recording sheet having a thermal transferable color material layer on one surface of a base film,
On the other side of the film, the following general formula (I) (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group or an aryl group, and at least one represents an aryl group)
The gist is a thermal transfer recording sheet having a layer of a polycarbonate resin having a repeating structural unit represented by:

The polycarbonate resin used in the present invention is obtained by reacting one or more phenolic compounds selected from the following general formula (IV) with phosgene according to a conventional method.

(In the formula, R ¹ and R ² have the same definitions as above.) At that time, one or more phenol compounds selected from the following general formula (V) may be used in combination.

(Where X is Represents a divalent group represented by —O—, —S—, —SO— or —SO ₂ —, R ³ and R ⁴ represent a hydrogen atom or an alkyl group, R ⁵ represents an alkylene group, and a benzene ring. A and B may have an alkyl group or a halogen atom.) The amount of the phenolic compound represented by the general formula (IV) used is in the range of 30 to 100 parts by weight, and the general formula (V The amount of the phenolic compound represented by) is 70 parts by weight or less.

Specific examples of the phenol compound represented by the general formula (IV) include bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) phenylmethane, and 1,1-bis (4-hydroxyphenyl). -1
-Phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, 1,1-bis (4-hydroxyphenyl) -1-phenylbutane and the like can be mentioned.

Further, specific examples of the phenol compound represented by the general formula (V) include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2.
-Bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4
-Hydroxy-3-methylphenyl) propane, 2,2-
Bis (hydroxyaryl) alkanes such as bis (4-hydroxy-3,5-dimethylphenyl) propane and 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis Bis (hydroxyaryl) cycloalkanes such as (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, 4,4 ′
-Dihydroxy-3,3'-dimethyldiphenyl ether and other dihydroxydiaryl ethers, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, etc. Dihydroxydiaryl sulfides, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-
Examples thereof include dihydroxydiaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxydiaryl sulfones such as 4,4′-dihydroxydiphenyl sulfone and 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone.

The polycarbonate resin used in the present invention has a reduced viscosity (ηsp / c) of 0.6 g / dl in a methylene chloride solution.
Those having a range of 0.22 to 1.50 measured at 0 ° C. are preferably used.

The heat-resistant protective layer of the above polycarbonate resin preferably contains a lubricant, a surfactant, heat-resistant fine particles and the like for the purpose of improving lubricity, preventing electrification and preventing blocking during winding of the sheet. Specific examples of these additives include the above-mentioned JP-A-59-196291 and JP-A-60-71.
292, JP-A-60-184883, 60-230896, 61-14992 and the like, among which, the following general formula (III) (Wherein R ⁶ represents an alkyl group, an alkenyl group, an aralkyl group or an aryl group, R ⁷ and R ⁸ represent a hydrogen atom or an alkyl group, and n represents an integer value of 1 to 50) Phosphoric acid ester compounds such as monoesters, diesters, triesters and monoesters of phosphoric acid and monoesters, alkali metal salts and alkaline earth metal salts of diesters have good heat resistance, lubricity and antistatic properties. It is particularly effective because it has good properties.

In order to form the heat-resistant protective layer of the above-mentioned polycarbonate resin on the thermal transfer recording sheet of the present invention, the polycarbonate resin is dissolved in a suitable solvent, and a lubricant, a surfactant, heat-resistant fine particles and the like are added to the solution. The heat-resistant protective layer can be easily formed by adding it as needed to prepare a coating solution, coating it on the base film, and drying it.

As a solvent for preparing the above coating solution, toluene,
Various solvents such as xylene, dioxane, tetrahydrofuran, chlorobenzene, o-dichlorobenzene, chloroform, methylene chloride and trichlene can be used, but toluene is particularly preferable from the viewpoints of economical efficiency, safety and easiness of handling.

The effective concentration of the polycarbonate resin in the coating liquid is in the range of 5 to 50% by weight, preferably 10 to 30% by weight.
The content of the surfactant fine particles and the like is 0.1 to 100% by weight, preferably 1 to 20% by weight, based on the polycarbonate resin. In addition to the above, a viscosity adjusting agent, a pH adjusting agent and the like may be further added to the coating liquid as needed, and a resin other than the polycarbonate resin is contained within a range not impairing the object of the present invention. Is also good.

As a method of applying the above-mentioned coating liquid, for example, use a gravure coater, a reverse roll coater, a wire bar coater, an air doctor coater, etc. shown in "Coating Method" by Yuji Harazaki (1979, Maki Shoten). You can Drying after coating is sufficient if the solvent is completely evaporated, and no further heat treatment is necessary.

The thickness of the heat-resistant protective layer formed by the above method is 0.
1 to 5 μm is suitable, and 0.3 to 3 μm is particularly suitable.

The base film used in the thermal transfer recording sheet of the present invention includes polyethylene terephthalate film,
Polyamide film, polyaramid film, polyimide film, polyetherimide film, polycarbonate film, polyphenylene sulphide film, polysulfone film, polyether sulphide film, polyether ether ketone film, cellophane, triacetate film, polypropylene film, etc. However, polyethylene terephthalate film is particularly advantageous in terms of mechanical strength, dimensional stability, heat resistance, economy and the like. The thickness of these base films is suitably from 1 to 30 μm, but preferably from 2 to 15 μm.

Further, in order to form the color material layer of the thermal transfer recording sheet,
In the case of a sublimation type thermal transfer recording sheet, an ink may be prepared by dissolving or dispersing a sublimable dye and a binder resin having good heat resistance in an appropriate solvent, coating the ink on a base film, and drying. In the case of a melt-type thermal transfer recording sheet, an ink is prepared by dissolving or dispersing a pigment such as a pigment or a dye in a heat-fusible substance using a solvent, if necessary, and the ink is used as a base film. It can be applied and dried.

Examples of the sublimable dye used in the sublimation type thermal transfer recording sheet include nonionic azo type, anthraquinone type,
Examples thereof include azomethine-based, methine-based, indoaniline-based, naphthoquinone-based, quinophthalone-based, and nitro-based dyes. As the binder resin, a usual polycarbonate resin from bisphenol A or the heat-resistant protective layer of the present invention Polycarbonate resin, polysulfone resin,
Examples thereof include polyvinyl butyral resin, polyarylate resin, polyamide resin, polyaramid resin, polyimide resin, polyetherimide resin, and cellulosic resins such as acetyl cellulose, methyl cellulose, ethyl cellulose and the like. As the solvent, toluene, aromatic solvents such as xylene, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone, ethyl acetate, ester solvents such as butyl acetate, isopropanol, butanol, alcohol solvents such as methyl cellosolve, Halogen-based solvents such as methylene chloride, trichloroethylene and chlorobenzene, Tethel-based solvents such as dioxane and tetrahydrofuran, amide-based solvents such as dimethylformamide and N-methylpyrrolidone are used. In the dyes used in the melt-type thermal transfer recording sheet, as pigments, inorganic pigments such as carbon black, various organic pigments of azo type and condensed polycyclic type, acid dyes having a sulfonic acid group, basic pigments dye,
Dyes such as metal complex salt dyes are also included, and as the heat-meltable substance, a solid or semi-solid substance having a melting point of 40 to 120 ° C. is preferable, and carnauba wax, montan wax, microcrystalline wax, wood wax, oil-based synthetic Wuxus and the like. Examples of the solvent include the same solvents as in the case of the sublimation type thermal transfer recording sheet.

In the above-mentioned ink, in addition to the above-mentioned components, organic and inorganic non-sublimable fine particles, a dispersant, an antistatic agent, an antiblocking agent, an antifoaming agent, an antioxidant, a viscosity modifier, etc. Can be added.

The ink can be applied by the same method as described for the application of the heat resistant protective layer, and the applied thickness is preferably 0.1 to 5 μm in dry film thickness. Further, in order to improve the adhesiveness between the base film and each layer formed by the above coating, the surface of the base film is corona treated or a resin such as polyester resin, cellulose resin, polyvinyl alcohol, urethane resin, polyvinylidene chloride. The undercoat treatment may be performed with.

[Action and effect]

The thermal transfer recording sheet of the present invention is easy to produce,
Further, when this sheet is used, a recording phenomenon with the thermal head does not occur even at the time of high-energy recording, the transportability is good, and since there is no adhesion of dust to the thermal head, good image quality recording can be obtained.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to examples, but the examples do not limit the present invention.

Example 1 (a) Preparation of coating solution for heat-resistant protective layer A phenolic compound shown in Table 1 below was reacted with phosgene according to a conventional method to produce a polycarbonate resin.

Reduced viscosity of obtained polycarbonate resin (ηsp / c)
And the glass transition point are shown in the first and the like.

A coating solution having the following composition was prepared using each of the polycarbonate resins shown in Table 1 above.

Composition of coating liquid for heat-resistant protective layer 20 parts by weight of polycarbonate resin (No. 1, 2, 3, 4 or 5 in Table 1) Phosphoric acid ester of polyoxyethylene alkyl ether (trade name: Prysurf A208B; Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts by weight Toluene 78 parts by weight (b) Preparation of thermal transfer recording sheet Biaxially stretched polyethylene terephthalate film (thickness 6 μm) with the above coating solution to a dry film thickness of about 1.5 μm with a wire bar coater To form a heat-resistant protective layer. Drying after coating was carried out at 80 ° C. for about 30 seconds. Next, on the opposite side of the heat-resistant protective layer, an ink containing 5 parts by weight of a cyan sublimable dye of the following general formula (VI), 10 parts by weight of the No. 1 polycarbonate resin shown in Table 1 above, and 85 parts by weight of toluene was used. After being prepared, this was applied and dried to form a color material layer having a dry film thickness of about 1.0 μm to prepare a thermal transfer recording sheet.

General formula (VI) (C) Transfer recording test and results The thermal transfer recording sheet prepared in (b) above is superposed on an image receiving paper having an image receiving layer made of a polyester resin containing a small amount of amino-modified silicone on a surface of polypropylene synthetic paper having a thickness of 150 μm. In addition, recording was performed under the following conditions using a line type thermal head having a heating resistor element having a density of 8 dots / mm.

Recording line density 8 lines / mm Thermal head applied power 0.4 W / dot Thermal head applied pulse width 1-10 ms Width of each pulse width while changing applied pulse width from 1 ms to 10 ms every 1 ms 5cm and 1cm length were recorded, but each sheet could record up to pulse width of 10ms without causing thermal head and stick phenomenon, and the conveyance of the sheet was good and good gradation could be obtained. did it. Also, recording was performed with a width of 5 cm and a length of 100 cm under the conditions of an applied power of 0.3 W / dot and an applied pulse width of 8 msec. In this case, there is no thermal head and sheet sticking phenomenon in each sheet. The conveyance was good, and cyan recording was possible with a uniform color density of about 1.8 on each sheet. After recording, no residue of thermal head was attached.

Example 2 The same material as in Example 1 was used and the thickness of the heat-resistant protective layer was 0.5.
The same test was performed by changing the thickness to 2.0 μm, but as in Example 1, there was no sticking phenomenon between the sheet and the thermal head, and the sheet was conveyed smoothly. In addition, it was possible to obtain a recording of good image quality without depositing dust on the thermal head.

Example 3 2 parts by weight of fine particles of a benzoguanamine resin (trade name: Eposta ^S ; manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) were added to the coating solution used in Example 1 to prepare a heat-resistant protective layer solution. A thermal transfer sheet was prepared and a transfer recording test was conducted in the same manner as in Example 1. However, there was no sticking phenomenon with the thermal head in each sheet, and the sheet was conveyed smoothly, and good quality image recording was obtained. did it. Further, there was no contamination of the thermal head after recording.

Example 4 Instead of the phosphoric acid ester used in Examples 1, 2 and 3, sodium salt of polyoxyethylene alkyl ether phosphoric acid ester (trade name: GAFACRD720; manufactured by Toho Chemical Co., Ltd.)
A transfer sheet was manufactured and a transfer recording test was conducted in the same manner as in Examples 1, 2 and 3 except that the sheet was not stuck to the thermal head, and the sheet was conveyed smoothly and had good image quality. I got the record. Further, there was no contamination of the thermal head after recording.

Example 5 In the production of a thermal transfer recording sheet, a polyester resin aqueous liquid is applied to both sides of the base film for the purpose of improving the adhesion of the heat-resistant protective layer and the color material layer to the base film before applying the layers. (Product name: Nichigo Polyester
WR-901; manufactured by Nippon Gosei Co., Ltd.)
After forming a 0.1 μm undercoat layer, a transfer recording sheet was prepared in the same manner as in Example 1. Using these transfer sheets, the same transfer recording test as in Example 1 was conducted. However, there was no sticking phenomenon with the thermal head in each sheet, and the sheets were conveyed smoothly, and recording with good image quality could be obtained. It was Further, there was no contamination of the thermal head after recording.

Example 6 A thermal transfer recording sheet was prepared and a transfer recording test was carried out in the same manner as in Example 1 except that the amount of the phosphoric acid ester of polyoxyethylene alkyl ether in the heat-resistant protective layer coating liquid of Example 1 was changed to 1 part by weight. As a result, each sheet did not cause a sticking phenomenon with the thermal head, and the sheets were conveyed smoothly, and good quality image recording could be obtained. Further, there was no contamination of the thermal head after recording.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-139983 (JP, A) JP-A-57-191091 (JP, A) JP-A-62-124989 (JP, A) JP-A-60- 76392 (JP, A)

Claims (9)

[Claims] 1. A thermal transfer recording sheet having a heat transferable color material layer on one surface of a base film, the following general formula (I) being provided on the other surface of the film. (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group or an aryl group, and at least one represents an aryl group)
A thermal transfer recording sheet having a layer of a polycarbonate resin having a repeating structural unit represented by: 2. A polycarbonate resin comprises a repeating structural unit represented by the general formula (I) and the following general formula (II). (Where X is ₂ represented by -O-, -S-, -SO- or -SO2-
Represents a valent group, R ³ and R ⁴ represent a hydrogen atom or an alkyl group, R ⁵ represents an alkylene group, and the benzene rings A and B may have an alkyl group or a halogen atom). The thermal transfer recording sheet according to claim 1, which is a polycarbonate resin composed of repeating structural units. 3. The thermal transfer recording sheet according to claim 1, wherein the polycarbonate resin layer contains a lubricant. 4. The thermal transfer recording sheet according to any one of claims 1 to 3, wherein the polycarbonate resin layer contains a lubricant and a surfactant. 5. The thermal transfer recording sheet according to any one of claims 1 to 3, wherein the polycarbonate resin layer contains a lubricant and heat-resistant fine particles. 6. The thermal transfer recording sheet according to any one of claims 1 to 3, wherein the polycarbonate resin layer contains a lubricant, a surfactant and heat-resistant fine particles. 7. The thermal transfer recording sheet according to any one of claims 3 to 6, wherein the lubricant is a phosphoric acid ester compound. 8. A phosphoric acid ester compound is represented by the following general formula (II
I) (In the formula, R ⁶ represents an alkyl group, an alkenyl group, an aralkyl group, or an aryl group, R ⁷ and R ⁸ represent a hydrogen atom or an alkyl group, and n represents an integer value of 1 to 50.)
The thermal transfer recording sheet according to claim 7, which is a phosphoric acid ester-based compound derived from a compound represented by: and phosphoric acid. 9. The thermal transfer recording sheet according to claim 1, wherein the base film is a polyethylene terephthalate film.