JPH0630971B2 - Thermal transfer material - Google Patents

Description

The present invention relates to a thermal transfer material. More specifically, the present invention relates to a heat-sensitive transfer material in which fusing (stick phenomenon) between the heat-sensitive transfer material and the thermal head during printing is prevented and the running is smooth.

[Conventional technology]

In recent years, various recording systems have been developed as office automation progresses, and among them, a thermal recording system, which produces less noise during printing and is easy to operate, is drawing attention.

Usually, a thermal recording system is used in which a thermal head is directly brought into contact with a thermal recording paper containing a special color-forming agent for recording. In this method, the thermal recording apparatus is excellent in operability and maintainability, but the recording paper is easily discolored by heat or light, and there is a big problem in long-term storage of the recording. Recently, the thermal transfer recording method has been widely used as a method of utilizing the advantages of the thermal recording method and eliminating the above disadvantages. The thermal transfer recording method is expected to be used in various printers in the future because it can print on plain paper, has excellent long-term storage stability of recording, and has excellent printing quality. As the printer, for example, a computer printer, a word processor printer,
Examples include video printers, label printers, still video camera printers, facsimile machines, and the like. Further, the recent development of computers has made it possible to easily display color graphics, and printers are entering the age of colorization.

In this method, a thermal transfer material composed of a base material and a thermal transfer layer applied on the surface thereof is used. When printing, contact the recording paper (generally plain paper can be used) with the thermal transfer layer of the thermal transfer material, pressurize it, contact the thermal head with the opposite surface of the substrate, and apply pulsed signal current to the head. Send and heat the thermal head. In this way, the heat-meltable ink layer is transferred only from the heat transfer layer of the heated portion, or the sublimable ink is sublimated,
Transfer and record on recording paper. Usually, the heat-meltable ink layer is easily transferred to a recording paper in the temperature range of 60 ° C to 120 ° C, and the sublimable ink is sublimated and transferred in the temperature range of 70 ° C to 200 ° C. Generally, the method using the former is called a heat-melting type heat-sensitive transfer method, and the method using the latter is called a sublimation-type heat-sensitive transfer method.

In the case of the heat-melting type thermal transfer method, for the black color printing, the thermal transfer material with carbon black added to the ink layer is used.
For colorization, a thermal transfer material of three primary colors of yellow, magenta, and cyan is separately prepared, and each color is heat-transferred three times on the same recording paper for a total of three times, and the three primary colors are superposed.

On the other hand, a major feature of the sublimation thermal transfer system is that gradation can be easily produced, that is, the amount of sublimated ink can be easily controlled by the amount of heat of the thermal head. If the color is desired to be dark, the applied voltage may be increased or the current pulse application time may be lengthened, and if the color may be desired to be light, the applied voltage may be lowered or the current pulse application time may be shortened. Utilizing the fact that this gradation can be easily produced, the present method is applied to color printing, particularly color printing of precise figures and photographs. Similar to the heat-melting type, the color printing method is a method in which heat-sensitive transfer materials of three primary colors of yellow, magenta, and cyan are prepared, and heat-sensitive transfer is performed once for each color, and a total of three are transferred. In the case of the sublimation type thermal transfer system, as described above, in order to darken the color, it is necessary to increase the amount of heat of the head.
High temperature is applied to the thermal transfer material. When sublimable ink is used in the thermal transfer method, a special image receiving layer may be provided on the recording paper for stability of color tone and maintainability. Since the recording can be easily performed, the disadvantages of the heat-sensitive recording method can be eliminated.

Conventionally, condenser paper has been used as the base material of this thermal transfer material, but it is necessary to make the base material thin to obtain high-speed printing and clear images because of its weak strength and easy tearing. However, it has been proposed to use a plastic thin film as the base material because it is difficult to reduce the thickness of the condenser paper and reduce the thickness unevenness.

[Problems to be solved by the invention]

By the way, when a plastic film is used as a base material, the following sticking phenomenon occurs, which causes a serious problem in its use.

That is, during recording, the surface temperature of the thermal head becomes equal to or higher than the melting point of the plastic film of the substrate, and the film in contact with the thermal head is fused to the thermal head,
Therefore, a sticking phenomenon occurs in which the feeding of the thermal transfer material is hindered. The sticking phenomenon causes a loss of clarity of recording, a loud noise is generated by forcibly peeling off the fused film, and in the worst case, the running is stopped, causing operational troubles. The sticking phenomenon is often seen especially in a sublimation type thermal transfer material having a high thermal head temperature.

[Means for solving problems]

In view of these facts, the present inventors have made earnest studies, and as a result, the coating solution containing a specific compound is applied to the surface on the side opposite to the surface on which the thermal transfer layer is provided to form a coating film. The inventors have found that the above can be solved and reached the present invention.

That is, the present invention, on one side of the polyester film
(A) A polycondensable organometallic compound and (B) a coating liquid containing a lubricant or a surfactant or (A) and (B) after coating a coating liquid containing a reacted compound, followed by stretching and drying. The heat-sensitive transfer material comprises a biaxially oriented polyester film having a coating film thus obtained and a heat transfer layer provided on the other surface thereof.

As the polyester film in the present invention, a linear saturated polyester film having a thickness of 2 μm to 20 μm can be used. If the thickness is too thin, the productivity of the film itself is poor, and if it is too thick, there is no point in using a plastic film. The linear saturated polyester is a highly crystalline linear saturated polyester synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol, and polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, polyethylene-2, 6-naphthalate and the like can be mentioned. Further, it may be a copolymer partially substituted with another component, or a blended product with another resin such as polyethylene glycol or polycarbonate. Usually, as the linear saturated polyester film, it is possible to use a film having an improved blocking property, which contains inorganic particles such as calcium carbonate, kaolin and silica, and precipitated particles formed from the catalyst residue used in the reaction. Many.

When manufacturing a thermal transfer material, a thermal transfer layer is provided on the opposite side of the coated surface of this film.However, if static electricity is generated on the film at this time, uneven coating will occur and the thermal transfer layer cannot be applied uniformly. May occur. In order to solve such a problem, it is preferable to use polyester obtained by subjecting polyester to antistatic treatment by a known method. For example, there is a method of adding 0.1 to 5% by weight of a sulfonate represented by the following structural formula to polyester.

R-SO ₃ Me RO-SO ₃ Me (The R in the above formula octyl, decyl, C ₃ ~ of dodecyl
C _{20 represents} an alkyl group, and Me represents an alkali metal or an alkaline earth metal. ) Such compounds include sodium octyl sulfonate, sodium decyl sulfonate, sodium dodecyl sulfonate, sodium octyl benzene sulfonate,
Examples thereof include sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, sodium nonylnaphthalenesulfonate, sodium dodecylnaphthalenesulfonate, potassium dodecylnaphthalenesulfonate, and the like.

These compounds may be used alone or in admixture of two or more.

The organometallic compound used in the present invention is, in its chemical bond, an organic compound having at least one chemical bond such as a metal-carbon bond, a metal alcoholate bond, a metal acylate bond, and a metal chelate bond, It refers to a compound that can easily form a polycondensate after hydrolysis without catalyst or in the presence of a catalyst. As the type of metal, aluminum,
Examples thereof may include silicon, titanium, chromium, zirconium, tin, etc., but are not necessarily limited to compounds of these metals. It is desirable to increase the adhesiveness between the coating film and the polyester film, and as the above compound, an organic silane compound and an organic titanium compound are preferable.

As the organic silane compound, tetraalkoxysilane,
A trialkoxysilane represented by the following formula (1) or (2),
Examples thereof include dialkoxysilane and a compound represented by the following formula (3).

(In the above formula, R ¹ and R ² are an alkyl group, a cycloalkyl group, a vinyl group, an alkenyl group, an aryl group, etc., and a part of hydrogen atoms of these groups is replaced with another atom such as halogen. the group, a hydroxyl group, a carboxyl group, an epoxy group, an epoxycyclohexyl group, a glycidoxy group, a methacryloxy group, amino group, diamino group, a ureido group, .R ³ showing a group obtained by substituting a reactive functional group such as a mercapto group A methyl group, an alkyl group such as an ethyl group, and a substituted alkyl group such as a methoxyethyl group are shown.) (R ⁴ ) _4-n —Si— (R ⁵ ) _n (3) (wherein R ⁴ is a methyl group, An ethyl group, a propyl group, an alkyl group such as a butyl group, a methoxy group, an alkoxy group such as an ethoxy group, a vinyl group, a phenyl group, a methacryloxy group, a group such as a methacryloxypropyl group, R ⁵ is a halogen atom, t An ert-butylperoxy group, an acyl group, an isocyanate group or the like is shown. n is a number of 1 to 4.) The alkyl group, cycloalkyl group, alkenyl group and alkoxy group preferably have 10 or less carbon atoms. Is.

Specific examples of these compounds include tetraethoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, meteltripropoxysilane, phenyltrimethoxysilane, dimethylmethoxysilane and vinyltriethoxysilane. Ethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-chloropropyltrimethoxysilane, β-
(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane,
γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl)
-Γ-aminopropyltrimethoxysilane, N-β-
(Aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane,
Examples thereof include γ-mercaptopropyltrimethoxysilane, diethyldichlorosilane, n-propyltrichlorosilane, tetraisocyanatesilane, phenyltriisocyanatesilane, and triisocyanatemethoxysilane, but are not limited thereto.

Examples of the organic titanium compound include titanium ester, titanium acylate, and titanium chelate compound. Specific examples include tetraisopropoxy titanium, tetrabutoxy titanium, tetrakis (2-ethylhexyloxy) titanium, diisopropoxybis (acetylacetonato) titanium, tetrakis (2-ethylhexanediolato) titanium, isopropoxy titanium. Examples thereof include, but are not limited to, tristearate, isopropoxytitanium tri (dioctyl phosphate), and the like.

In the present invention, one kind or a mixture of two or more kinds of these organometallic compounds can be used as it is or partially hydrolyzed, or as a low polymer of the hydrolyzate.

The lubricants and surfactants (hereinafter referred to as "lubricants and the like") used in the present invention include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorochemical surfactants. , Organic carboxylic acids and their derivatives, higher aliphatic alcohols, paraffins, waxes,
Examples thereof include organopolysiloxane. These compounds are usually commercially available as lubricants, surfactants or waxes, and their boundaries are not always clear. A compound obtained by introducing a reactive functional group into these compounds may be used.

Examples of the anionic surfactant include carboxylic acid salts, sulfuric acid ester salts of higher alcohols, sulfonates, phosphoric acid esters of higher alcohols and salts thereof which are usually commercially available. Specific examples of these compounds include sodium laurate, sodium stearate,
Sodium oleate, sodium lauryl alcohol sulfate, sodium myristyl alcohol sulfate, sodium cetyl alcohol sulfate, sodium stearyl alcohol sulfate, sodium oleyl alcohol sulfate, sodium sulfate of higher alcohol ethylene oxide adduct, sodium octyl sulfonate, Sodium decyl sulfonate, sodium dodecyl sulfonate, sodium octylbenzene sulfonate, sodium dodecyl benzene sulfonate, potassium dodecyl benzene sulfonate, sodium nonyl naphthalene sulfonate, sodium dodecyl naphthalene sulfonate, potassium dodecyl naphthalene sulfonate, N-oleoyl -N-methyl taurine sodium, tetra Butoxy lauryl alcohol phosphate ester, sodium phosphate monostearyl esters, and the like phosphoric acid distearyl ester sodium, but is not limited thereto.

The cationic surfactant may be a commercially available product, and examples thereof include higher alkyl amines and ammonium salts obtained from them, and neutralized products of esters of ethanol amine and higher fatty acids, but are not limited thereto. Not a thing.

Examples of the amphoteric surfactant include amino acid type ones such as sodium laurylaminopropionate and betaine type ones such as laurylmethyl betaine, but are not limited thereto.

Examples of the nonionic surfactant include polyalkylene glycol compounds containing an adduct of polyalkylene oxide as a main component, esters of polyhydric alcohols, ethers of polyhydric alcohols, fatty acid amides of alcohol amines, and the like. Specifically, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, copolymers of these glycols, higher fatty acid mono-, di-, or triglycerides, higher fatty acid sorbitan, mono,
Examples thereof include, but are not limited to, di- or triesters and amides of higher fatty acids and alcohol amines.

As the fluorine-based surfactant, a liquid, semi-solid or solid carbon fluoride derivative can be used. As such a compound, a sulfonate or carboxylate having a perfluoroalkyl group having 5 or more carbon atoms, a perfluoroalkyl phosphate ester, a perfluoroalkylethylene oxide adduct, a perfluoroalkyl sulfinic acid halide or an amino alcohol. Examples thereof include a sulfinic acid derivative such as a reaction product with a class, a low polymer of a vinyl compound containing a perfluoroalkyl group, or a low polymer copolymerized with another vinyl monomer. Among these compounds, compounds having particularly excellent releasability and slipperiness and effective in preventing the staking phenomenon include compounds having a relatively high molecular weight such as low polymers and copolymer low polymers. it can.

Examples of organic carboxylic acids and their derivatives include higher fatty acids, aromatic carboxylic acids, higher fatty acid esters or amides, and aromatic fatty acid esters or amides.

Examples of higher fatty acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid,
Examples thereof include montanic acid and n-hexatetracosanoic acid. Derivatives of higher fatty acids, many of which are contained in nonionic surfactants, include ethylene bis-stearic acid amide, butylene bis-stearic acid amide, N, N'-bisstearyl terephthalamide, but are not limited to these. It is not something that will be done.

Examples of the higher fatty acid alcohol include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol and behenyl alcohol.

As the wax, various natural waxes and synthetic waxes can be used.

Examples of the organopolysiloxane include silicone oil and various modified silicone oils having various functional groups introduced therein in order to enhance compatibility, hydrophilicity, reactivity, adsorptivity, lubricity and the like.

The following formulas are specific examples of silicone oil and various modified silicone oils. In R, R'is a methyl group, R'is a long-chain alkyl group or an alkyl group containing an aromatic group, a polyether, a hydroxyl group or an alkyl group containing a hydroxyl group, an amino group or an amino group. Examples thereof include modified silicone oils that are alkyl groups, higher fatty acids, or fluorine-containing alkyl groups. Further, modified silicone oil containing an alcoholic hydroxyl group or a carboxyl group at both ends of the above structural formula may also be mentioned,
It is not limited to these compounds.

Among the above-mentioned lubricants and the like, preferable examples include metal sulfonates, sulfuric acid ester salts of higher alcohols, phosphoric acid esters of higher alcohols and salts thereof, fluorine-based surfactants, esters and amides of higher aliphatic carboxylic acids. And organopolysiloxanes.

When the lubricant or the like and the organometallic compound have a reactive functional group, the reaction product of both may be used. Such examples include perfluoroalkylcarboxylic acid fluorides and perfluoroalkylsulfinic acid fluorides and N-
Examples thereof include a reaction product with β (aminoethyl) -γ-aminopropyltrimethoxysilane.

The coating liquid of the present invention comprises the above-mentioned (A) organometallic compound and
Although it contains (B) a lubricant or the like, or contains the reactants of (A) and (B), it may be used as it is or diluted with a solvent. As such a solvent, one or two of water, methanol, ethanol, isopropanol, methyl cellosolve, methyl ethyl ketone, toluene, etc.
Mention may be made of mixtures of more than one species. Although there is no particular limitation on the ratio of the lubricant or the like and the organometallic compound,
When there is no reactive functional group, the lubricant or the like is contained in the solid content of 1% to 80%. If it is too small, the wettability and releasability will not be exhibited, and if it is too large, the adhesiveness of the coating layer will be poor. When the lubricant or the like has a reactive functional group, the compounding ratio thereof can be increased, and particularly in the case of reacting with the organometallic compound, it can be added up to an amount to complete the reaction.

In the present invention, the coating method may be any known method as long as it can be applied thinly, and a method using a rod coater, a gravure coater, various roll coaters or the like is used. The thickness of the coating layer is usually
It is set to 0.005 μ to 2 μ. It is preferably 0.01 μm to 1 μm. If the thickness is too thin, the lubricity is poor, and if there is a certain thickness, no further thickness is needed.

As for the timing of application, the polyester film before the crystal orientation is completed may be applied, and then dried or not dried, and stretched and heat-treated to complete the crystal orientation.

In this case, for example, in the case of the sequential biaxial stretching method, a coating solution is applied to a longitudinally uniaxially stretched polyester film, dried appropriately (or not dried), and then a moving clip stretches the film horizontally in a scissor tenter. And heat treatment. According to this method, equipment for coating layer simultaneously with stretching,
Further, the coating film can be dried, the operation is simplified, and the coating film is stretched after coating, so that the coating film can be easily thinned. Since the releasability and lubricity effective for preventing the sticking phenomenon are chemical and physical phenomena on the very surface layer of the film, it is important to keep the coating layer as thin as possible. If the coating layer is thick, the adhesiveness to the film is poor, and when the film is wound into a roll, the coating layer is transferred to the opposite surface.
This method has a feature that a thin coating film can be easily formed. The heat treatment temperature of the above method is 180 to 25
About 0 ° C is preferable. High heat may be required to form the coating layer into a strong coating film, but in order to treat with such high heat in the method of applying to the biaxially stretched film, a commonly used apparatus, Further, there is a need for a device that prevents the film from shrinking due to heat. However, in the above-mentioned method, high heat treatment can be easily performed, and if an appropriate organometallic compound and lubricant are selected, high heat treatment results in extremely high adhesiveness to the polyester film,
Moreover, it is possible to produce a polyester film which is remarkably excellent in releasability and slipperiness, and in which the coating layer does not transfer to the opposite surface.

The transfer layer of the heat-sensitive transfer material of the present invention comprises a colorant and a binder. In the case of the heat-melting type thermal transfer system, pigments such as carbon black and various dyes widely used in the copying field can be used as the colorant. As the binder, carnauba wax, montan wax, microcrystalline wax, wood wax, oil-based synthetic wax and the like can be used.

Examples of the colorant in the case of the sublimation thermal transfer method include sublimable dyes such as azo dyes and anthraquinone dyes, and carboxymethylcellulose as a binder.
Examples thereof include methyl cellulose, ethyl cellulose, nitrocellulose, alginic acid derivatives, polysulfone, polyether sulfone, polyarylate, and polyetherimide.

In the present invention, when adhesion of the coating film or the heat transfer layer to the biaxially stretched polyester film is poor, corona treatment or undercoating treatment may be performed.

〔The invention's effect〕

According to the present invention, when the coating solution is heated and dried at 60 ° C. to 250 ° C. after application, the organometallic compound, its hydrolyzate or the low polymer of the organometallic compound in the coating solution is used in the absence of a catalyst or In the presence of a catalyst such as acetic acid or sodium acetate, it forms a condensate, forms a non-greasy coating film, and prevents lubrication sites that react with lubricants and organometallic compounds from sticking. A smooth thermal transfer material can be obtained.

〔Example〕

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "part" means "part by weight". Viscosity measurement, surface roughness measurement, evaluation of the thermal transfer material, etc. were performed as follows.

Measurement of viscosity: 1 g of polyester film is dissolved in 100 ml of a mixed solvent of phenol / tetrachloroethane = 1/1 (weight ratio), and the viscosity is measured at 30 ° C.

Measurement of surface roughness: Crushed on a film stand, using a three-dimensional roughness measuring instrument manufactured by Kosaka Laboratory Ltd., under the conditions of a needle radius of 20 μ and a load of 30 mg.
The film surface is measured over 25 mm at a speed of 0.1 mm / sec, 100 times in the standard length direction and 50000 in the surface roughness direction.
The roughness curve is obtained by magnifying twice. From the roughness curve, a part of the measurement length L is extracted in the direction of the center line, and the center line of this extracted part is represented as the X axis, and the longitudinal magnification direction is represented as the Y axis. The roughness curve is represented by y = f (x). At that time, the value given by the following equation is expressed in μm.

At the time of measurement, the cutoff value is 0.08 mm.

12 points were measured, and an average value was obtained for 10 points excluding the maximum value and the minimum value.

Evaluation of thermal transfer material Evaluation was performed using a line printer P6 manufactured by Fuji Zerox, a typewriter EP-20 manufactured by Brother Industries, Ltd., and a thermal head capable of changing the ink temperature from 140 ° C to 200 ° C.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.66 and containing 0.08 part of amorphous silica having an average diameter of 1.5μ was used.
It was melt extruded at 5 ° C, cast on a cooling drum at 60 ° C, and then stretched 3.5 times in the machine direction. On one side of this longitudinally stretched film, Megafac F-117 20 manufactured by Dainippon Ink and Chemicals, Inc., which is mainly composed of a low polymer of a vinyl monomer containing a fluorocarbon surfactant and a perfluoroalkyl group.
Part, γ-glycidoxypropyltrimethoxysilane 75
Parts, a 3 wt% aqueous solution of 5 parts of polyalkylene glycol having a molecular weight of 20,000 (copolymer in which polyethylene glycol is polymerized at both ends of polytetramethylene glycol) so that the coating amount becomes 4.5 g / m ² And then stretched 3.7 times in the transverse direction at 110 ° C,
Heat setting was performed at 230 ° C. The obtained film had a thickness of 6 μm and Ra of 0.129 μm. On the opposite side of the coating layer of the film, a hot-melt ink comprising 20 parts of carbon black, 40 parts of carnauba wax and 40 parts of aliphatic ester wax was melt-coated at a coating amount of about 4 g / m ² ,
A thermal transfer material was obtained. When these thermal transfer materials were evaluated by Fuji Xerox Co., Ltd. line printer P6, no stick phenomenon was observed.

Comparative Example 1 Using a biaxially stretched polyethylene terephthalate film having a Ra of 0.028 μm and a thickness of 9 μ and containing 0.08 part of amorphous silica having an intrinsic viscosity of 0.61 and an average diameter of 1.7 μm,
A thermal transfer material was obtained without providing a coating layer.

Comparative Example 2 A thermal transfer material was obtained in exactly the same manner as in Example 1 except that the coating layer did not contain a lubricant or the like. When this heat-sensitive transfer material was evaluated in the same manner as in Example 1, a stick phenomenon occurred and it did not run.

Claims (1)

[Claims] 1. A coating solution containing (A) a polycondensable organometallic compound and (B) a lubricant or a surfactant or a compound obtained by reacting (A) and (B) on one surface of a polyester film. A heat-sensitive transfer material comprising a biaxially oriented polyester film having a coating film obtained by applying a coating liquid containing the film, stretching the film, and then drying the film, and providing a thermal transfer layer on the other surface of the film.