JPH1058845A - Transfer material for thermal recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate creases, folds and the like to be generated particularly remarkably in widening and realize the highly minute printing quality by forming a heat-sensitive transfer layer on one face of a base film composed of aromatic polyamide having the Young's modulus in the specified longitudinal direction. SOLUTION: Aromatic polyamide represented by the formula I and/or formula II (In the formulas, Ar1 , Ar2 and Ar3 represent aromatic uncles, R, R' and R" represent a functional group selected out of halogen, nitro, cyanogen, 1-4C alkyl, 1-3C aocoxy, trialkylsiril, oxyaryl, thioaryl and aryl, and (l), (m) and (n) represent 0-4 integer.) is used as a base film. The Young's modulus EMD in the longitudinal direction of the base film at the temperature of 20 deg.C and relative humidity of 60% is 6.86 GPa or more. Also the dimension variation rate after treating the base film at 200 deg.C for 10 minutes is preferably 2% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer material for thermal recording which is suitable for multi-use and excellent in print quality.

[0002]

2. Description of the Related Art Conventionally, polyester, polypropylene, cellophane, acetate, polycarbonate, paper, etc. have been used as a base material for a thermal recording transfer material (hereinafter abbreviated as a thermal transfer material). Films, especially polyethylene terephthalate (hereinafter abbreviated as PET), have been widely used.

In recent years, even in the case of such materials, the thickness of the heat-sensitive transfer layer has been reduced due to the need for high-definition printing quality typified by measures such as enhancing the energy transfer efficiency from the head and the increase in the thickness of the heat-sensitive transfer layer corresponding to multi-use. The request has been made. However, a substrate such as the PET described above has insufficient heat resistance and rigidity and is deformed under tension, so that a highly rigid substrate is required. From such a viewpoint, proposals to use a highly rigid aromatic polyamide film as a substrate have been made in JP-A-60-174694 and JP-A-61-61694.
237687, JP-A-63-107588, and the like.

Further, in a thermal transfer material using an aromatic polyamide film, Japanese Patent Application Laid-Open No. Hei 4-318034 discloses that the thermal shrinkage at 200 ° C. is set to 5% or less, whereby wrinkles due to film shrinkage are generated. There is a description that this is preferable because it is suppressed.

[0005]

In recent years, from the standpoint of environmental protection, movements corresponding to multi-use have become mainstream in the field of thermal transfer materials. This multi-use technology involves printing with a transfer agent accumulation layer inside the heat-sensitive transfer layer or a multi-layered transfer agent layer to limit release per printing. Since it is necessary to increase the loading amount of the agent per base material surface area, the base material must be thinned in order to keep the total thickness below a certain value.

A technique called the n-fold method is a method of recording a recording material and a thermal transfer material with a certain relative speed ratio to save the area of the thermal transfer material to be used. And the heat history time becomes longer, so that the substrate is required to have higher heat resistance than before. In addition, since a large friction is generated due to a difference in running speed between the recording material and the thermal transfer material, even a slight dimensional change of the thermal transfer material causes erosion and wrinkles, and adversely affects printing characteristics.

[0007] However, PET has a limitation in thinning due to rigidity restrictions, and is not necessarily sufficient to meet the above-mentioned needs. In addition, when thermal energy is applied from a thermal head or the like, the head softens due to thermal softening. It is necessary to further provide an anti-sticking layer on the head side because of the sticking phenomenon of burning. It has been found that the number of steps is increased and this is not necessarily economically advantageous. In addition, the heat resistance is insufficient, so that it is not suitable for high definition as described later.

Further, in order to respond to the need for increasing the printing speed, it is necessary to increase the energy density of the head, and as a result, the temperature of the thermal transfer material tends to increase. Recording methods are broadly classified into a fusion transfer type and a sublimation type, but it is said that the latter is more advantageous for higher definition of print quality.
However, the sublimation recording system generally requires high energy. Furthermore, halftone expression is the highest requirement for high definition, but technologies such as concentrated heating transfer method and multi-valued release of transfer agent are expressed by the amount of applied energy, and materials that can withstand high energy That is, a material having heat resistance is required. The aromatic polyamide is useful in terms of high rigidity and high heat resistance. However, there is a strong demand for higher definition, and therefore it is necessary to further reduce the thickness from the viewpoint of accurately and efficiently transmitting energy from the head. Since it is necessary not to sacrifice productivity, it is necessary to increase the rigidity of the heat-sensitive transfer material and further reduce the dimensional fluctuation due to heat as much as possible.

In addition, the use of color printing, multi-line printing, and the adoption of line heads has led to a trend toward wider thermal transfer materials.
Thermal dimensional changes, especially non-uniformity, cause curling and wrinkling, and impair printing accuracy and print quality.

Regarding the problem of thermal dimensional change, the above-mentioned Japanese Patent Application Laid-Open No. Hei 4-318034 merely discloses that the heat shrinkage rate is 5%.
It is only stated that the following is preferable, and no specific means for realizing it, consideration of the change in thermal dimensions, and technical ideas are described. Also, Japanese Patent Application Laid-Open No. 61-2376
No. 87 discloses an example in which a heat-sensitive transfer material having a limited heat shrinkage rate is obtained by using an aromatic polyamide having a special structure, but there is a limitation on film formation of an aromatic polyamide (solution film formation). There is no mention of the non-uniformity of the in-plane thermal dimensional change caused by the above, and as is clear from the examples of the publication, such a special structure has a shortage of Young's modulus, and only a thick film can be used. The printing characteristics are inferior.

The present invention has been made as a result of intensive studies from this viewpoint, and its purpose is to regulate the Young's modulus and the thermal dimensional fluctuation without impairing the heat resistance and mechanical properties inherent to aromatic polyamide. Accordingly, it is an object of the present invention to provide a heat-sensitive transfer recording material excellent in printing quality and processing characteristics, particularly suitable for multi-use.

[0012]

That is, the present invention relates to a transfer material for heat-sensitive recording comprising a heat-sensitive transfer layer provided on one surface of a base film made of an aromatic polyamide. A Young's modulus EMD in the longitudinal direction at a humidity of 60% is 6.86 GPa or more, and the base film is a film that maintains a substantially flat surface after being subjected to a heat treatment at 200 ° C. for 10 minutes. This is a heat-sensitive recording transfer material.

In the present invention, the solvent solution of the aromatic polyamide is discharged from a die, cast on a support, and if necessary, treated under dry heat and / or wet heat, and then the solvent is extracted and heat-fixed. In obtaining a transfer material for thermosensitive recording by providing a heat-sensitive transfer layer on the obtained film, a temperature difference between two arbitrary points in the vicinity of the die discharge portion is controlled to 10 ° C. or less and / or a discharge thickness is obtained. When controlling the unevenness to within 10% and performing the treatment under dry heat or wet heat, the variation in the temperature and / or the water vapor content near the film in the treatment tank is controlled within 5% in the width direction of the base film. When processing in a liquid medium, the medium is brought into contact with the surface of the film with flow, and a means for removing the adhered medium at the outlet after the processing is used. Is a Utsushizai method of manufacturing.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The aromatic polyamide referred to in the present invention is represented by the following general formula (I) and / or general formula (II):

Embedded image General formula (II)

Embedded image (Where Ar ₁ , Ar ₂ and Ar ₃ are aromatic nuclei, and R, R ′ and R ″ are a halogen group, a nitro group, a cyano group, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 3 carbon atoms. A functional group selected from an alkoxy group, a trialkylsilyl group, an oxyaryl group, a thioaryl group, and an aryl group;
m and n are integers of 0-4. ), And preferably contains 50 mol% or more of the repeating unit represented by the general formula (I) and / or (II), more preferably 70 mol% or more.

Here, Ar ₁ , Ar ₂ and Ar ₃ are represented, for example, by the general formula (III)

Embedded image And the like, X, Y is _{-O -, - CH 2 -,} - CO
_{-, - SO 2 -, -} S -, - C (CH 3) 2 - is chosen from such, but is not limited thereto.

From the viewpoint of characteristics, those in which the above-mentioned aromatic rings are bonded at the para-position account for at least 50%, preferably 75%, of the total aromatic rings.
% Of the polymer is preferable because the film has high rigidity and good heat resistance.

The term "para-bond" means that the bonding direction of the main chain in the aromatic ring is located at the para-position, or that the main chains at both ends of the residue comprising two or more aromatic rings are coaxial or parallel. Means Examples of such aromatic rings include those of the general formula (IV).

General formula (IV)

Embedded image The aromatic polyamide contains 50 mol% of a repeating unit represented by the general formula (I) and / or the general formula (II).
As long as it satisfies the present invention, other repeating units such as an aromatic polyimide or aromatic polyamideimide structure may be copolymerized or blended.

In order to improve the humidity characteristics of the aromatic polyamide, some of the hydrogen atoms on these aromatic rings are replaced with R, R in the general formulas (I) and / or (II).
A halogen group (particularly chlorine) represented as R ′, R ″,
Substitution with a substituent such as a nitro group, an alkyl group having 1 to 4 carbon atoms (particularly a methyl group), or an alkoxy group having 1 to 3 carbon atoms can be preferably performed. The values of l, m and n in the general formula (I) or (II) are arbitrary, but in the general formula (I), l + m is 1 or more and 4 or less, preferably 2 or more and 4 or less and l> It is practical to set 0 and m> 0. When l + m exceeds 5, the film becomes brittle, which is not preferable. In the general formula (II), it is practical that n is 0 or more and 2 or less, preferably 1 or more and 2 or less. Of the substituents that can be introduced, preferred substituents include chlorine, methyl, and methoxy groups, since there is almost no decrease in mechanical properties, and are excellent in wet heat resistance and have a small decrease in elongation. Therefore, chlorine is more preferable. However, when it is feared that a halogen compound or a nitrogen compound is generated by thermal decomposition or the like, it is preferable that the amount of the aromatic ring substituted with the halogen group or the nitro group is less than 15% of the total aromatic ring.

In consideration of the influence on the thermal head, the content of ionic impurities in the base film used in the present invention, particularly ions of IA, IIA and VIIB groups of the periodic table, especially IA group, Group IIA ions are 300 ppm or less, preferably 100 ppm or less, more preferably 10 ppm or less.
It is good that it is below ppm. The amount of the ionic impurities is determined as an amount extracted by heating and refluxing the substrate in hot water for 24 hours. When these ionic impurities are contained, the risk of damage to the thermal head is great. In addition, it is possible to preferably perform preparation so as to fall within this range by coating a part or the whole of the base film with a non-permeable material of an ionic impurity, and the layer is functionally a mat layer described later. ,
It preferably has one of the functions of an anchor layer and an anti-sticking layer. In order to reduce the amount of ionic impurities in the base material, it is important to select the purity of the raw material, the type of additive, the type of catalyst, and the selection of the polymerization conditions. be able to.

The content of the oligomer having a molecular weight of 1,000 or less contained in the substrate film used in the present invention is 0.1%.
It is preferably at most 5% by weight, more preferably at most 0.2% by weight. The oligomer referred to herein is one containing even a part of the molecule constituting the aromatic polyamide,
A reaction product with a solvent or the like is also included. If a large amount of these oligomers remain in the substrate, they will precipitate out during use and cause poor adhesion to the thermal transfer layer and other components formed on the substrate surface, causing problems such as peeling and poor print quality. is there. In addition, it becomes easy to wind around a roll or the like, which may cause generation of wrinkles and wrinkles.

When the weight average molecular weight of the aromatic polyamide constituting the substrate film used in the present invention is Mw and the number average molecular weight is Mn, it is preferable that the following formula is satisfied: Mw / Mn ≦ 4.5 Preferably, 1.2 ≦ Mw / Mn ≦ 3.5. In general, aromatic polyamides are polymerized in a heterogeneous system, so that the molecular weight distribution tends to fluctuate. However, aromatic polyamides satisfying the above formula have remarkably good film-forming properties and good heat resistance.

The base film 20 used in the present invention
The Young's modulus EMD in the longitudinal direction at 60 ° C. and a relative humidity of 60% must be 6.86 GPa or more, and preferably 7.86 GPa.
It is 84 GPa or more, more preferably 8.82 GPa or more. When the thickness is within the range of the present invention, the thin material has sufficient rigidity in the longitudinal direction, so that it can withstand the tension during processing or use and does not deteriorate the print quality.

Further, when the Young's modulus in the width direction at 20 ° C. and a relative humidity of 60% is defined as ETD, the following equation is preferably used: EMD ≧ ETD × 1.1 ETD ≧ 6.86 GPa, preferably, EMD ≧ ETD × 1.1 ETD ≧ More preferably, it satisfies EMD ≧ ETD × 1.2 ETD ≧ 7.84 GPa. By controlling within this range, it can withstand stress during processing and has excellent slitting properties. It is possible to obtain a recording material that is hardly damaged on the cut surface and has excellent durability. On the other hand, if the ETD is less than 6.86 GPa, the stiffness in the width direction is insufficient, and wrinkles are likely to occur, leading to cutting during the production of the recording material or transfer recording or a reduction in print quality. Because it is too strong, it may cause a decrease in elongation or cause breakage or tearing.

The base film used in the present invention is 20
The dimensional change after treatment at 0 ° C. for 10 minutes is preferably 2% or less, more preferably 1% or less, and further preferably 0.5% or less. Since the heat-sensitive transfer material is used without receiving tension, particularly in the width direction, it is easily affected by dimensional fluctuation due to heat. If the dimensional change rate exceeds 2%, when used as a heat-sensitive transfer material, the dimensional change is caused by heating by a thermal head, which often causes wrinkles and makes the product useless. In particular, in a full-color printing application using a line head, for example, a structure in which four color transfer layers of yellow, cyan, magenta, and black are provided in parallel in the width direction is often used. Become. In such a case, if there is a dimensional change due to heat, the positional accuracy is inferior, and the print quality particularly at the end of the print surface may be reduced.

After the substrate film is treated at 200 ° C. for 10 minutes, it is necessary that the substrate film be kept substantially flat. Here, to maintain a substantially flat surface is evaluated by the ratio of the contact area to the flat surface with respect to the total area when the heat-treated base film is spread on the flat surface.
0% or more, preferably 70% or more, more preferably 80% or more.
% Or more. However, when the substrate film is elongated, the curvature is evaluated as 2% or less, preferably 1.5% or less, and more preferably 1% or less. Aromatic polyamide films are usually obtained from solution casting, but the disadvantage of the casting process is the inhomogeneity of in-plane physical properties. When the film leaving such a defect as the base film, wrinkles are likely to occur even in a slight heat shrinkage, particularly when the large-area heat-sensitive transfer material as described above is used,
This causes a decrease in print quality.

The base film used in the present invention preferably has an elongation of 10% or more, preferably 20% or more, and more preferably 30% or more, because of excellent toughness and moderate flexibility.

The base film used in the present invention has a high Young's modulus and can be made relatively thin. However, the thickness is adjusted to various modes, preferably 0.5 to 20 μm, more preferably 1 to 10 μm, and further preferably 2 to 10 μm. To 8 μm, particularly preferably 3 to 7 μm. If the thickness is too large, the transfer of energy is not performed precisely, so that the print quality is degraded. If the thickness is too small, deformation tends to occur under stress.

The film of the present invention may be laminated, and may be composed of the same polymer type or different polymer types. Further, it is preferable that the above-mentioned properties are satisfied also when a laminated film is formed.

In the present invention, particles can be preferably contained in the base material for various purposes such as stabilization of running properties and enhancement of energy transfer speed.

The type of such particles is not particularly limited. For example, SiO ₂ , TiO ₂ , TiN, A
l ₂ O ₃ , ZrO ₂ , CaCO ₃ , CaSO ₄ , BaS
Examples include inorganic particles such as O ₄ , talc, zeolite, and other fine metal powders, and organic particles such as carbon black and cross-linked polystyrene resin. However, particles colored other than white, such as carbon black, are not preferred because they contaminate the head or printed surface during running. Further, too hard particles are not preferable because they may wear the head.

The content of the particles contained in the film is 0.01 to 40% by weight, preferably 0.05 to 10% by weight.
% By weight.

As will be described later, it is preferable to design the surface roughness of the front and back surfaces of the base material according to different design ideas. One way to realize such an idea is to use polymers having different chemical compositions, higher-order structures, or particles. It is preferable that at least two or more layers containing particles having different diameters, hardness, and the like are laminated to form a substrate.

When the surface of the base film on which the heat-sensitive transfer layer is not provided has an appropriate roughness, the running property can be improved, and the surface side can conform to JIS-B-0601-1976. The center line average roughness Ra measured (cut off: 0.25 μm) is 2 to 700 nm, preferably 10 to 50 nm.
It is preferably in the range of 0 nm, more preferably in the range of 20 to 400 nm. If it is less than 2 nm, the runnability deteriorates and print quality is adversely affected. If it exceeds 700 nm, energy transfer efficiency and energy transfer unevenness are reduced due to the layer of air generated between the recording material and the head, resulting in print quality deterioration. Becomes Further, if the surface of the heat-sensitive transfer layer surface of the base film also has an appropriate roughness, without contaminating the recording material by friction with the recording material,
Since the running property is also good, the surface side has a center line average roughness Ra of 3 to 300 nm, preferably 10 to 200 nm as described above.
It is preferably in the range of nm. If it exceeds 300 nm, the positional accuracy of the transfer is deviated and the print quality is reduced.

The present invention is a thermal transfer recording material. As a printing method which can be applied, any of a heat transfer type and a sublimation type may be used.Therefore, a known pigment-based or dye-based paraffin may be used as a heat-sensitive transfer layer provided as necessary.
Known waxes such as carnauba and esters and various polymer materials can be used as the binder resin. Further, between the base layer and the heat-sensitive transfer layer, a layer of an acrylic resin, a urethane resin, a polyester resin, or the like can be interposed, and these may contain additives such as an antistatic agent. . A back coat layer can be preferably provided on the side opposite to the surface on which the heat-sensitive transfer layer is formed, for the purpose of enhancing running properties. Examples of such a back coat layer include waxes such as carnauba and esters, thermosetting resins, silicone resins, fluororesins, and those obtained by adding a surfactant to these resins.

The present invention employs an aromatic polyamide having excellent heat resistance and maintains a substantially flat surface even at a high temperature, so that it is generally used as a sublimation type thermal recording transfer material for printing at a high temperature. And particularly suitable for application to a transfer material for thermal recording employing the multi-use technique as described above. It is also excellent in adaptability to widening, and the width of the thermal recording transfer material is preferably 100 mm or more,
More preferably 200 mm or more, particularly preferably 250 mm
mm or more, and is suitable for printing on paper of A4 or B4 standard or higher employing a line head.
There is no particular upper limit on the width, but the width is regulated by restrictions on the printer design.

Next, the method for obtaining the present invention will be specifically described, but the thermal transfer material of the present invention is not limited to this description.

The method for obtaining the aromatic polyamide includes, for example, a low-temperature solution polymerization method, an interfacial polymerization method, a melt polymerization method, and a solid-phase polymerization method. In the present invention, a solution system, particularly a low-temperature solution polymerization method, is used. It is suitable because polymerization is easily obtained as a highly rigid substrate.

As the polymerization solvent, known solvents such as N-methylpyrrolidone (NMP), dimethylacetamide (D
An aprotic organic polar solvent such as MAc) or dimethylformamide (DMF) is used. At this time, it is preferable to remove impurities such as moisture in the polymerization solvent as much as possible in order to suppress the formation of oligomers. Lithium chloride, lithium bromide, calcium chloride and the like may be added as a dissolution aid. Next, monomers (eg, diamine and diacid chloride) are added. At this time, if the acid chloride is divided and added, heat generation can be suppressed and generation of oligomers can be prevented, but the molecular weight distribution tends to be broad. Equivalence of diamine and acid chloride is very important for increasing the degree of polymerization of the aromatic polyamide, but when the degree of polymerization needs to be adjusted, the diamine component is excessively increased due to its excellent thermal stability. It is preferable to use benzoyl chloride or the like, and the terminal can be preferably blocked.

It is preferable to use a reaction vessel capable of stirring as efficiently as possible. The reaction of forming an aromatic polyamide often generates a large amount of heat, and therefore it is preferable to stir at a high speed in the early stage of the polymerization. On the other hand, when the viscosity increases with an increase in the degree of polymerization, high-speed stirring is rather inefficient. Since any of the above cases causes the formation of oligomers, it is preferable to have a mechanism capable of adjusting the stirring speed by the degree of polymerization (viscosity).
Further, by optimizing such means, the degree of polymerization can be increased and the degree of dispersion can be reduced, and the value obtained by dividing the number average molecular weight by the weight average molecular weight is 4.5 or less, preferably 1 which is suitable for the present invention. .2 to 3.5.

When an acid such as hydrogen chloride is contained in the polymer solution, when neutralizing the acid, an inorganic neutralizing agent such as calcium hydroxide, calcium carbonate, lithium carbonate, ethylene oxide, Organic neutralizing agents such as propylene oxide, ammonia, triethylamine, triethanolamine, diethanolamine and the like are used. Generally, these neutralizing agents can act as the above-described impurity components that lower the print quality, but as described later, these contained impurity components can be effectively removed by optimizing the film forming process.

These polymer solutions may be used directly as a stock solution for film formation, or the polymer solution may be isolated once and then redissolved in the above organic solvent or an inorganic solvent such as sulfuric acid to prepare a stock solution for film formation. Good. Further, the polymer concentration is preferably about 2 to 40% by weight.

To obtain an aromatic polyamide suitable for the present invention, the intrinsic viscosity of the polymer (0.5 g of
(Measured at 30 ° C. as a 00 ml solution) is 0.5
It is preferable that it is above.

The method of adding the particles is not particularly limited. In order to adjust the degree of aggregation and suppress the appearance of coarse projections, for example, a method of previously dispersing the particles in a solvent of 10 poise or less, preferably 1 poise or less. Can be mentioned. The solvent is preferably the same as the one used at the time of film formation, but when no adverse effect is particularly observed, another solvent may be used. In addition, additives such as a dispersing agent may be used in these solvents as long as they do not adversely affect the dispersion. The particles are dispersed using a stirring disperser, a ball mill, an ultrasonic disperser or the like, and the particle diameter and the degree of aggregation are adjusted.

The dispersed particles are mixed with the polymer solution, and may be added to a solvent before polymerization, added after polymerization or added at the time of preparing the polymer solution, and may be added immediately before casting. It is important that they are uniformly dispersed in the stock solution in terms of running properties and ensuring good print quality.

The film-forming stock solution prepared as described above is formed into a film by a so-called solution casting method. There are no problems with the solution film forming method, including dry-wet method, dry method, wet method, etc., but the dry method cannot remove non-volatile impurities including ionic impurities. Not a target.

In the film formation, first, the undiluted solution was transferred from a die to nickel,
It is extruded on a support such as a drum or endless belt made of a material such as stainless steel, copper, titanium, hastelloy, and tantalum to form a thin film. At this time, the temperature difference between any two points in the vicinity of the die is controlled to 10 ° C. or less, preferably 6 ° C. or less, more preferably 4 ° C. or less.
Within 5%, preferably within 5%, more preferably within 2%. Without the control, the drying of the solvent, the extraction behavior of the solvent, and the drying behavior of the gel film in the subsequent steps become non-uniform, and as a result, the physical properties (particularly, thermal dimensional change) in the in-plane direction become non-uniform. For such control, not only control of the shape of the base and the distance between the base lips, but also the entire base under an atmosphere at a constant temperature close to the temperature of the polymer solution, temperature control by mounting a sensor on the heater for heating the base, etc. Take the means of.

Next, if necessary, the solvent is evaporated from the thin film layer, and the film is dried or wet-treated until the thin film has a self-holding property. Drying conditions are, for example, room temperature to 250 ° C,
The reaction can be performed in a range of 60 minutes or less, preferably in a range of room temperature to 200 ° C. If the temperature exceeds 250 ° C., the surface may be roughened, which may cause a decrease in print quality. At this time, the amount of drying in the width direction of the thin film should be constant, and the temperature variation in the width direction of the thin film in the vicinity of the thin film layer in the processing tank should be within 5%, preferably within 3%. When the thin film layer is treated in a wet state, the thin film layer is absorbed by passing through an atmosphere having a temperature of 50 ° C. or higher and a relative humidity of 70% or higher, or by blowing a gas under the above conditions. Also at this time, the variation of the water vapor content in the width direction of the thin film in the vicinity of the thin film layer in the processing tank is kept within 5%. Even without such control, the physical properties (especially, thermal dimensional change) become non-uniform in the in-plane direction. For such control, a sufficiently large processing tank is used, or the output of the heater or the steamer at the end of the thin film layer is slightly increased.

The film after the above treatment is peeled off from the support or introduced into the wet process while being supported on the support. However, in order to effectively remove impurities in the wet process, the film loses its self-holding property. It is preferable that the polymer concentration in the thin film is as low as possible within a range not present, and the object can be easily achieved if the polymer concentration is 50% or less. The peeled film is then subjected to desalting, solvent removal, and the like, and is further stretched, dried, and heat-treated to form a film.

In the present invention, the wet process and the stretching / heat treatment process play an important role. In the wet process, water may be used as a desolvent, but a mixed medium of water and an organic solvent or an aqueous solution of an inorganic substance can be suitably used. At this time, the organic solvent is water-soluble, and preferably, like the polymerization solvent, N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF)
Aprotic organic polar solvents such as are preferred. In the wet process, the solvent or salt in the thin film is extracted, but if the extracted solvent or the like stays in the vicinity of the thin film, the extraction efficiency will not be constant and the physical properties of the film will be non-uniform in the subsequent process. In the present invention, such a control is provided with a circulating device or a blowing device so that a flow forcibly generated on the film surface is so controlled as to minimize variations in the bath composition concentration near the thin film. In addition, when air is entrained in the running film and air bubbles adhere to the surface of the thin film and are introduced into the bath, the extraction behavior differs only in that portion and the film properties become non-uniform. Immediately afterward, a guide is provided to remove bubbles. When a plurality of baths having different bath composition ratios are used, ionic impurities and other unnecessary additives can be discharged out of the system, and a more suitable film can be obtained. The lower the temperature, the better the result is a dense film. However, if the bath composition is appropriate, it is preferable to increase the temperature within a range that does not impair the object of the present invention from the viewpoint of speed.

The gel film that has undergone the wet process is then subjected to a stretching and heat treatment process. If the gel film is introduced with a solvent adhered to the surface thereof, it causes nonuniformity in thermal dimensional change. An apparatus such as a nip roll or a roll provided with a suction means, a mechanical means such as a scraper, or a small amount is passed through a hot plate or atmosphere at about 100 ° C. to remove the adhering solvent and then stretched and heat-treated. Stretching is a stretching ratio of 0.8 to 5.0 (area ratio is defined as a value obtained by dividing the area of the film after stretching by the area of the film before stretching. 1 or less means relaxation). It is preferably within the range, more preferably 1.0 to 3.5 times. At this time, the Young's modulus of the present invention can be satisfied by increasing the stretching ratio in the longitudinal direction. Furthermore, 200 ° C to 500 ° C, preferably 2 ° C
By performing heat treatment and relaxation treatment at a temperature of 50 ° C. to 400 ° C. for several seconds to several minutes, mechanical properties, thermal properties, thermal dimensional change rate, and dimensional change unevenness in a plane are further improved. Further, by gradually cooling the film after the heat treatment, the thermal dimensional change rate and the in-plane dimensional change unevenness are further improved, and it is effective to cool the film at a rate of 50 ° C./sec or less. In the present invention,
In stretching and heat treatment, it is necessary that the temperature in the vicinity of the base film is 5% or less in the width direction. When the control is not carried out, on average, even if the thermal dimensional change rate is within the preferred range of the present invention, a portion having a high temperature is more stretched or crystallized, which may cause unevenness in thermal dimensional change of the product. Become. For such control, in the present invention, measures such as using a sufficiently large heat treatment tank or slightly increasing the heater output at the end of the film are taken. In addition, heating means using dielectric heating or infrared rays can also be used.

The film of the present invention may be a laminated film. For example, in the case of two layers, the polymerized aromatic polyamide solution is bisected, and different particles may be added as necessary, and then laminated. The same applies to the case of three or more layers. These laminating methods include well-known methods such as lamination in a die, lamination in a composite tube, and a method in which one layer is formed once and another layer is formed thereon. In the laminated film of different components, it is preferable that each layer satisfies the condition of the above-mentioned unevenness of the discharge thickness.

Next, a heat-sensitive transfer layer and the like are formed on the obtained base material.

As the hot-melt transfer agent, a colorant and an ethylene-vinyl alcohol copolymer, paraffin wax,
It is prepared by blending carnauba wax and the like. As the colorant, a colorant of another color can be used in addition to a colorant forming cyan, magenta, yellow, and black.
The amount of the transfer agent to be applied is arbitrary depending on the purpose, but a thickness of 3 to 20 μm is appropriate for stably performing high-quality printing.

Examples of the heat sublimable transfer agent include anthraquinone, azo, naphthoquinone, polymethylene, and the like.
Dyes (preferably using disperse dyes) such as triphenylmethane, phenoxazine, leuco auramine, and spiropyran, binders such as polyvinyl butyral, polysulfone, polycarbonate, polyphenylene oxide, and cellulose materials, and other additives Is dispersed or dissolved in a solvent. The amount of the transfer agent to be applied is arbitrary depending on the purpose, but is suitably 0.5 to 20 μm in thickness.

As a means for performing printing many times, a conventionally known method can be used. For example, the heat softening point is higher than the melting point of the transfer agent or the temperature at which sublimation starts, and the affinity with the transfer agent is low. Examples of the method include a method of forming a transfer layer using a binder, and a method of forming a transfer layer by adding particles having extremely high cohesiveness.

The anchor layer can be formed arbitrarily. As the anchor layer, a resin having good adhesiveness to the thermal transfer layer may be selected from conventionally known resins and used.

The mat layer can be formed arbitrarily. This mat layer can be selected from known materials having heat resistance and heat release properties, and has a thickness of 0.1 to 3 μm.
A thin film having such a degree is preferable because the thermal sensitivity becomes good.

Examples of the resin forming the mat layer include synthetic resins such as acrylic resins, polyester resins, phenol resins, fluororesins, polyimide resins, and silicone resins having a glass transition point of 60 ° C. or higher, or OH.
A resin obtained by adding a compound having two or more amino groups or a di (or tri) isocyanate to a thermoplastic resin having a group or a COOH group is preferable.

In addition, waxes such as polyethylene wax and paraffin wax as heat releasing agents and lubricants, amides, esters and salts of higher fatty acids, phosphates such as higher alcohols and lecithin, Teflon, polyvinyl fluoride, etc. Fluorine resin, guanamine resin, silica, talc, calcium carbonate, magnesium carbonate, precipitated barium sulfate, alumina, acid clay, titanium white, carbon black and the like may be added.

The above-mentioned anchor layer and mat layer can be formed by dissolving or dispersing these constituent materials in a solvent as appropriate, adjusting the viscosity to a level suitable for coating, and using a known coating means.

A sticking prevention layer may be formed on the thermal head side if necessary. The constituent components and the forming method can be selected in the same manner as in the formation of the mat layer described above, and can further contain a conductive substance and a coloring agent.

In order to improve the running property, the coefficient of kinetic friction with glass is preferably 1.0 or less, which corresponds to the type of component such as a lubricant contained in the base film or in the anti-sticking layer. And the size, content, thickness, and the like.

The present invention is suitable for recording using a thermal head. However, heating means other than the thermal head, for example, heat generation in a base film by passing through a hot stamping plate, a laser beam, electricity or the like. It can also be used for recording using the means.

[0065]

EXAMPLES The method for measuring physical properties and the method for evaluating effects according to the present invention are as follows. In this example, the following physical properties (1) to (5) are obtained by removing portions other than the base material from the thermal transfer recording material obtained by performing the processing described in (6) on the base film raw material. It is. In addition, the test length and test width of the base material are determined for the sake of convenience, and it can be easily analogized even by those skilled in the art that these physical property values are essentially unrelated.

(1) Tensile elongation and Young's modulus Measured using an Instron type tensile tester. The test piece is 10 mm wide and 50 mm long, and the pulling speed is 300 mm / min. A sample was prepared using a thermo-hygrostat at a temperature and humidity of 20 ° C. and 60% RH for 48 hours.

(2) Thermal dimensional change rate In the longitudinal direction and / or the width direction of the base film,
The specimen was cut into a width of 10 mm and a length of 250 mm, and a mark was placed at a position 25 mm from each end to prepare a test piece having a test length of 200 mm. This was introduced into an oven maintained at 200 ° C. under no tension, the length after heating and cooling for 10 minutes was measured, and the thermal dimensional change rate was calculated by the following formula. The value of each was defined as the thermal dimensional change rate.

(Test length (mm) -Length after heating (mm)) / (Test length
(mm)) × 100 (%)

(3) Flatness after heat treatment For a substrate film of at least 500 cm ² (however, sample as square or circular as possible)
Thick Exaine (manufactured by Toray Industries, Inc.) in which the heat treatment of (2) above was performed and the base film after the treatment was spread on a flat plate.
Spread it up with a brush. Next, the area that swelled without contact was marked to measure the area, which was determined by the following equation.

(1- (area of marking portion) / (base film area before heat treatment)) × 100 (%)

If the width of the base film is less than 50 mm, a straight line having a length of 100 cm is drawn in the longitudinal direction at intervals of 3 to 5 mm at an interval of 50 mm from the end of the base film having a length of 110 cm. . Next, the heat treatment (2) is performed. The processed film is spread on grid paper, and the maximum deviation from the straight line connecting both ends is calculated for each of the base film edge and the straight line described above, and calculated by the following formula, and the largest value is obtained. Is the evaluation value.

(Distance) / (length of film or straight line before heat treatment) × 100 (%)

(4) Amount of ionic impurities The cations and anions are represented by the following formulas (4-1) and (4-2)
And the sum was defined as the amount of ionic impurities.

(4-1) Qualitative and Quantitative Determination of Metal Ions 20 grams of the base film was precisely weighed and refluxed in hot water for 24 hours to extract ionic compounds. The solution after filtration was evaporated to dryness, dissolved in nitric acid or hydrofluoric acid, and then adjusted to a constant volume with diluted nitric acid. In this constant volume solution, K and Na were analyzed by atomic absorption spectrometry, and the other components were analyzed by ICP emission spectrometry. The unit ppm is μg / g.

(4-2) Anion Content 20 g of the base film was precisely weighed and refluxed in hot water for 24 hours to extract an ionic compound. Next, the extract was quantified by ion chromatography based on a previously prepared calibration curve. The unit ppm is μg / g.

(5) Oligomer Content and Molecular Weight Distribution The film was dissolved in a solvent and subjected to gel permeation chromatography (GPC) using a low angle laser light scattering photometer (LALL).
S) and a differential refractometer (RI) are incorporated, and the molecular weight and the content of the solute are sequentially determined by measuring the light scattering intensity and the refractive index difference of the molecular chain solution size-separated by a GPC device according to the elution time. After calculating, the absolute molecular weight distribution of the high molecular weight substance was finally calculated. Diphenylmethane was used for calibration of the absolute molecular weight.

As a simple method, it is also possible to simply obtain a fraction having a molecular weight of 1,000 or less from a solution obtained by size separation and remove the solvent.

(6) Print Quality Corona treatment was performed on the surface of the base film on which the heat-sensitive transfer layer was to be formed, and then an anchor layer made of an acrylic resin was formed.

Next, a coating composed of four kinds of sublimable dye-binder mixtures of yellow, cyan, magenta and black was applied and dried to form a thermal transfer recording layer of four colors.

Dye 10 parts by weight Particle-containing polyvinyl butyral resin 20 parts by weight Toluene 90 parts by weight Methyl ethyl ketone 90 parts by weight Using this sheet, a printing machine equipped with an A4-size edge type line head was applied with a power of 20 W / mm ² , a pulse width of 4 ms, Full-color printing was performed at a pressure of 110 g / cm, and the printing characteristics were determined. The print quality was evaluated in the following evaluation stages.

A: Excellent. ：: Excellent. ：: good. Δ: Equal or slightly dissatisfied level. ×: Bad.

Examples 1 to 8 and Comparative Examples 1 to 6 The abbreviations shown in the raw material column are as follows.

Aromatic diamine component: MA: metaphenylenediamine CPA: chloroparaphenylenediamine DPX: 2,5′-dimethylparaphenylenediamine DMB: 3,3′-dimethylbenzidine DOB: 3,3′-dimethoxybenzidine DPE: 4,4'-diaminodiphenyl ether acid chloride component: TPC: terephthaloyl dichloride IPC: isophthaloyl dichloride CTPC: chloroterephthaloyl dichloride

Example 1 CPA equivalent to 80 mol% as an aromatic diamine component and DPE equivalent to 20 mol% were dissolved in N-methylpyrrolidone (NMP), and CTPC equivalent to 100 mol% was dissolved therein. The polymerization was completed by adding and stirring for 2 hours, initially at high speed and slowly reducing speed. This was neutralized with lithium hydroxide to obtain an aromatic polyamide solution having a polymer concentration of 10% by weight.

Next, a silica particle slurry having an average particle diameter of 0.8 μm previously dispersed in NMP was added to the aromatic polyamide solution so as to have a polymer ratio of 1.0% by weight.
Evenly distributed.

After passing this polymer solution through a filter having a cut of 20 μm, 10 heating blocks having a control thermocouple are arranged in the width direction in the vicinity of the outlet of the mouthpiece to cover the mouthpiece, and each of them is heated to 50 ° C. Cast on a stainless steel belt from the mouthpiece, and adjust the hot air temperature and air volume for each nozzle individually in a dryer that can automatically adjust the average temperature to 18.
The solvent was evaporated by heating at 0 ° C. for 2 minutes, and the film having self-holding property was continuously peeled off from the belt. At this time, it was confirmed that the actual temperature unevenness in the width direction was within 3 ° C. in the vicinity of the die discharge portion. Also, four groups of thermocouples at four points in the width direction were arranged in the dryer in the longitudinal direction (they were arranged substantially evenly with respect to the film in the dryer), and the temperature near the film was observed. It was confirmed that the temperature difference was within 3 ° C. in each measurement group in the direction.

Next, a water / NMP ratio maintained at 30 ° C. is a forced circulation mechanism having a concentration ratio of 7/3, 8/2, 9/1 and 10/0, respectively, and a water tank equipped with a nip roll at the final bath outlet. Then, a film was introduced into the solution to extract a residual solvent and an inorganic salt. At this time, the film was stretched 1.2 times in the longitudinal direction by utilizing the peripheral speed difference of the roll. Next, moisture drying and heat treatment were performed at 285 ° C. with a tenter capable of automatically adjusting the hot air temperature and air volume of each nozzle individually to obtain an aromatic polyamide film having a thickness of 6 μm. During this time, the film was stretched 1.2 times in the width direction, and then heat-treated at a constant length of 300 ° C.
It was gradually cooled at a rate of 20 ° C./sec. Also at this time, four groups of thermocouples at four points in the width direction were arranged in the tenter in the longitudinal direction (they were arranged substantially evenly with respect to the film in the tenter), and the temperature near the film was observed. It was confirmed that the temperature difference was within 3 ° C. in each measurement group in the direction.

The Young's modulus EMD of this film is 9.8 GP
a, ETD 8.33 GPa, elongation is 47 in the longitudinal direction.
%, Thermal dimensional change rate is 0.2%, flatness after heat treatment is 75%
%, Oligomer content is less than 0.2% by weight, Mw / Mn
Is 2.4, the content of ionic impurities is less than 10 ppm,
The surface roughness Ra of the substrate on which the transfer layer was not provided is 40 n
m.

The printing quality of the heat-sensitive transfer recording material using this film was excellent, and almost no deterioration was observed even after recording many times. Also, there was no particular problem in the process of processing the thermal transfer recording material.

Example 2 An aromatic polyamide film was obtained in the same manner as in Example 1 except that the film was stretched 1.25 times in a wet bath.

The Young's modulus EMD of this film is 10.29.
GPa, ETD 8.03 GPa, elongation in the longitudinal direction is 40
%, Thermal dimensional change rate is 0.2%, flatness after heat treatment is 65%
%, Oligomer content is less than 0.2% by weight, Mw / Mn
Is 2.4, the content of ionic impurities is less than 10 ppm,
The surface roughness Ra of the substrate on which the transfer layer was not provided is 40 n
m.

The printing quality of the heat-sensitive transfer recording material using this film was good, and almost no deterioration was observed even after recording many times. Further, it was found that even if the pulse width was increased by 1 ms, elongation was not recognized and there was a thermal margin. In addition, there was no particular problem in the processing step for the thermal transfer recording material. On the contrary, the slitting property was improved and the defective rate was reduced.

Example 3 Example 1 was repeated except that CTPC was divided into 5 portions and added over 40 minutes.
Polymerization was performed using the same method as described above, and particles were added. In the wet process, stretching was not performed, and 1.
An aromatic polyamide film having a thickness of 6 μm was obtained in the same manner as in Example 1 except that the film was formed twice and 1.1 times in the width direction, and further subjected to a heat treatment under a 1% relaxation condition.

The Young's modulus EMD of this film is 9.31 G
Pa, ETD8.33 GPa, elongation in the longitudinal direction is 28%,
Thermal dimensional change rate is 0.1% or less, flatness after heat treatment is 80
% Or more, oligomer content is less than 0.2%, Mw / Mn
Is 3.7, the content of ionic impurities is less than 10 ppm,
The surface roughness Ra of the substrate on which the transfer layer was not provided is 40 n
m.

The printing quality of the thermal transfer recording material using this film was excellent, and almost no deterioration was observed even after recording many times. Also, there was no particular problem in the process of processing the thermal transfer recording material. However, the base film is somewhat brittle and has a low manufacturing process margin.

Example 4 Example 1 except that the stirring speed was not controlled during the polymerization.
Polymerization was performed using the same method as described above, and particles were added. Also,
In the wet process, a pressure roll equipped with a suction mechanism is used instead of the nip roll, and in this process, stretching is not performed,
The same method as in Example 1 was used except that the film was formed 1.2 times in the longitudinal direction and 1.1 times in the width direction in the tenter, and the thickness was 6 μm.
Was obtained.

The Young's modulus EMD of this film was 10.29.
GPa, EtD 8.82 GPa, elongation in the longitudinal direction is 42
%, Thermal dimensional change rate is 0.2%, flatness after heat treatment is 75%
%, The oligomer content is 0.7% by weight, the Mw / Mn is 3.2, the ionic impurity content is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 40 nm.
Met.

The printing quality of the heat-sensitive transfer recording material using this film was excellent, and hardly any deterioration was observed even after a large number of recordings. However, it seems that the recording material tends to accompany the running roll as the number of recordings increases. Was.

Example 5 Polymerization was carried out in the same manner as in Example 1 to obtain a polymer solution.
Then, the polymer solution was divided into 2 minutes, and a silica particle slurry having an average particle diameter of 0.3 μm previously dispersed in NMP was added to the first component so as to have a polymer ratio of 2% by weight.
A silica particle slurry having an average particle size of 1.2 μm was similarly added to the component (2) so as to have a polymer ratio of 0.5% by weight, and was uniformly dispersed.

Then, the first component and the second component are cast while being laminated in a merging tube. In the wet process, a pressure roll provided with a suction mechanism is used in place of the nip roll.
Further, at the time of stretching, a film was formed in the same manner as in Example 3 except that the stretching ratio was 1.25 times in the longitudinal direction and 1.1 times in the width direction, to obtain an aromatic polyamide film having a thickness of 6 μm.
Then, a thermal transfer layer was formed on the surface of the film on which the first component was laminated.

The Young's modulus EMD of this film is 10.78.
GPa, ETD 8.04 GPa, elongation in the longitudinal direction is 38
%, Thermal dimensional change rate is 0.1% or less, flatness after heat treatment is 80% or more, oligomer content is less than 0.2% by weight, M
w / Mn is 2.5, ionic impurity content is 10 pp
m, surface roughness Ra of the substrate on which the transfer layer is not provided
Is 300 nm, and the surface roughness Ra of the substrate on the side where the transfer layer is provided is Ra.
Was 20 nm.

The printing quality of the heat-sensitive transfer recording material using this film was remarkably excellent, and no deterioration was observed even after recording many times. In addition, the processing characteristics were good, and the reject rate was significantly reduced.

Example 6 DPX equivalent to 40 mol% as an aromatic diamine component
And DOB corresponding to 40 mol% and DPE corresponding to 20 mol% are dissolved, and T mol corresponding to 100 mol% is dissolved therein.
The PC was added and the polymerization was completed by initially stirring for 2 hours at high speed and slowly reducing speed. This was neutralized with lithium hydroxide to obtain an aromatic polyamide solution having a polymer concentration of 7% by weight.

Next, a silica particle slurry having an average particle diameter of 0.8 μm previously dispersed in NMP was added to the aromatic polyamide solution so as to have a polymer ratio of 1.0% by weight.
Evenly distributed.

After passing this polymer solution through a filter having a cut of 20 μm, 10 heating blocks having a control thermocouple are arranged in the width direction in the vicinity of the outlet of the base to cover the base, and each of them is controlled at a temperature of 60 ° C. Cast on a stainless steel belt from the base that has been set, and the average temperature of 17 in a dryer that can automatically adjust the hot air temperature and air volume of each nozzle individually.
The solvent was evaporated by heating at 0 ° C. for 2 minutes, and the film having self-holding property was continuously peeled off from the belt. At this time, it was confirmed that the actual temperature unevenness in the width direction was within 3 ° C. in the vicinity of the die discharge portion. Also, four groups of thermocouples at four points in the width direction were arranged in the dryer in the longitudinal direction (they were arranged substantially evenly with respect to the film in the dryer), and the temperature near the film was observed. It was confirmed that the temperature difference was within 3 ° C. in each measurement group in the direction.

Next, a pressurized circulation system having a water / NMP ratio maintained at 30 ° C. and having a concentration ratio of 7/3, 8/2, 9/1, and 10/0, respectively, and a pressurization system having a suction mechanism at the final bath outlet. The film was introduced into a water tank equipped with a roll to extract residual solvent and inorganic salts. Next, moisture drying and heat treatment were performed at 280 ° C. with a tenter capable of automatically adjusting the hot air temperature and air volume of each nozzle individually to obtain an aromatic polyamide film having a thickness of 6 μm. During this time, 1.
The film was stretched twice and 1.1 times in the width direction, and then heat-treated at a constant length of 290 ° C. and then gradually cooled at a rate of 20 ° C./sec. At this time, the thermocouple group of 4 points in the width direction was
The temperature in the vicinity of the film was observed by arranging it in the longitudinal direction of group 0 (they were arranged almost evenly with respect to the film in the tenter). The temperature difference in each measuring group in the width direction was within 3 ° C. It was confirmed.

The Young's modulus EMD of this film is 9.8 GP.
a, ETD 8.33 GPa, elongation in longitudinal direction 35%, thermal dimensional change 0.1%, flatness after heat treatment 75%, oligomer content less than 0.2% by weight, Mw / Mn 2 .
8. The content of ionic impurities was less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer was not provided was 40 nm.

The printing quality of the heat-sensitive transfer recording material using this film was excellent, and almost no deterioration was observed even after recording many times. Also, there was no particular problem in the process of processing the thermal transfer recording material.

Example 7 As monomers, DPX corresponding to 35 mol%, 30
DMB corresponding to 2 mol%, 2 corresponding to 20 mol%,
2′-dimethylbenzidine, DP corresponding to 15 mol%
E. Polymerization was carried out in the same manner as in Example 6 except that TPC corresponding to 100 mol% was used, and particles were added. Next, a 6-μm-thick aromatic polyamide film was obtained in the same manner as in Example 6, except that a 1% relaxation treatment was performed during the heat treatment.

This film has a Young's modulus EMD of 9.8 GP.
a, ETD: 8.33 GPa, elongation in the longitudinal direction: 35%, thermal dimensional change rate: 0.1% or less, flatness after heat treatment: 80%
As described above, the oligomer content was less than 0.2% by weight, Mw / M
n is 2.8, the content of ionic impurities is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 4
It was 0 nm.

The printing quality of the thermal transfer recording material using this film was extremely excellent, and no deterioration was observed even after recording many times. Also, there was no particular problem in the process of processing the thermal transfer recording material.

Example 8 As monomers, CPA equivalent to 70 mol%, 30
DPE corresponding to mol%, CT corresponding to 100 mol%
Polymerization was carried out in the same manner as in Example 1 except that PC was used, and particles were added in the same manner. Next, a film was formed in the same manner as in Example 6, except that the stretching temperature was 285 ° C, the stretching ratio was 1.15 times in the longitudinal direction, 1.1 times in the width direction, and the heat treatment temperature was 290 ° C.
An aromatic polyamide film having a thickness of 6 μm was obtained.

The Young's modulus EMD of this film is 7.05 G
Pa, ETD 7.64 GPa, elongation in the longitudinal direction is 47%,
Thermal dimensional change rate is 0.6%, flatness after heat treatment is 75%,
The oligomer content is less than 0.2% by weight, Mw / Mn is 2.5, the content of ionic impurities is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 40 nm.
Met.

The printing quality of the thermal transfer recording material using this film was good, but there was no margin in the usable temperature, and there was a concern that the performance would deteriorate in many-time recording. Although there was no particular problem in the process of processing the thermal transfer recording material, there was a tendency for the film to break when processing at a higher speed than in the other examples.

Comparative Example 1 As monomers, MA corresponding to 100 mol% and 50
IPC corresponding to mol%, TPC corresponding to 50 mol%
Polymerization was carried out in the same manner as in Example 1 except for using, and particles were added in the same manner. Next, a film was formed in the same manner as in Example 6 except that the stretching temperature was 270 ° C. and the heat treatment temperature was 285 ° C.
A μm aromatic polyamide film was obtained.

The Young's modulus EMD of this film is 6.37 G
Pa, ETD 5.4 GPa, elongation in the longitudinal direction 47%, thermal dimensional change 2.5%, flatness after heat treatment 65%, oligomer content less than 0.2% by weight, Mw / Mn 2 .
7. The content of ionic impurities was less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer was not provided was 40 nm.

The thermal transfer recording material using this film was stretched at the time of printing, frequently wrinkled and degraded, and could not be used at all as print quality.

Comparative Example 2 As a monomer, CPA corresponding to 60 mol%, 40
DPE corresponding to mol%, CT corresponding to 100 mol%
Polymerization was carried out in the same manner as in Example 1 except that PC was used, and particles were added in the same manner. Then, the stretching temperature was 270 ° C., the stretching ratio was 1.1 times in both the longitudinal and width directions, and the heat treatment temperature was 2
A film was formed in the same manner as in Example 6 except that the temperature was 85 ° C., and the thickness was 6 μm.
m was obtained.

The Young's modulus EMD of this film is 6.66 G
Pa, ETD 6.66 GPa, elongation in the longitudinal direction is 49%,
Thermal dimensional change rate is 1.1%, flatness after heat treatment is 70%,
The oligomer content is less than 0.2% by weight, Mw / Mn is 2.4, the content of ionic impurities is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 40 nm.
Met.

The thermal transfer recording material using this film was stretched at the time of printing, though not as much as in Comparative Example 1, and wrinkles and cracks occurred. The print quality was unusable.

Comparative Example 3 The temperature of the die was monitored at one point in the center of the die to control the temperature. Polymerization was carried out in the same manner as in Example 1 except that the polymer solution was discharged, and a film was formed in the same manner as in Example 4. Was. Further, when the drying was stopped, only the casting was performed, and the thickness unevenness of the cast was measured. As a result, the unevenness of thickness exceeded 10%.

The Young's modulus EMD of this film was 10.29.
GPa, EtD 8.82 GPa, elongation in the longitudinal direction is 42
%, Thermal dimensional change rate is 0.2%, and flatness after heat treatment is 60%.
%, Oligomer content is less than 0.2% by weight, Mw /
Mn is 2.5, the content of ionic impurities is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 4
It was 0 nm.

The thermal transfer recording material using this film suffered from wrinkling and printing during printing. The print quality was unusable.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 1 except that the forced circulation mechanism was stopped in the wet process, and a film was formed in the same manner as in Example 4.

The Young's modulus EMD of this film was 10.29.
GPa, EtD 8.82 GPa, elongation in the longitudinal direction is 42
%, Thermal dimensional change rate is 0.2%, and flatness after heat treatment is 60%.
%, Oligomer content is less than 0.2% by weight, Mw /
Mn is 2.5, the content of ionic impurities is less than 10 ppm, and the surface roughness Ra of the substrate on which the transfer layer is not provided is 4
It was 0 nm.

The thermal transfer recording material using this film produced wrinkles and burns during printing, although not as much as in Comparative Example 3.
The print quality was unusable.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 1 except that the pressure roll provided with the suction mechanism at the final bath outlet was removed in the wet process, and a film was formed in the same manner as in Example 4.

The Young's modulus EMD of this film is 10.29.
GPa, EtD 8.82 GPa, elongation in the longitudinal direction is 42
%, Thermal dimensional change rate is 0.3%, and flatness after heat treatment is 60%.
%, Oligomer content is 0.3% by weight, Mw / Mn
Was 2.5, the content of ionic impurities was 15 ppm, and the surface roughness Ra of the substrate on which the transfer layer was not provided was 40 nm.

The heat-sensitive transfer recording material using this film produced wrinkles and burns during printing in Comparative Example 3 and higher. The print quality was unusable. Further, slight coloring was observed in the thermal head.

Comparative Example 6 The control of the hot air temperature and the air volume for each nozzle in the tenter was changed to a method of controlling the value at one nozzle at the center in each section partitioned in the longitudinal direction. Polymerization was conducted in the same manner as in Example 1 except for the above, and a film was formed in the same manner as in Example 4. At this time, when the temperature unevenness in the bath was measured with another thermocouple, a difference of about 15 ° C. occurred in the width direction.

The Young's modulus EMD of this film was 10.29.
GPa, EtD 8.82 GPa, elongation in the longitudinal direction is 42
%, Thermal dimensional change rate is 0.3%, and flatness after heat treatment is 60%.
%, Oligomer content is 0.2% by weight, Mw / Mn
Is 2.5, the content of ionic impurities is less than 10 ppm,
The surface roughness Ra of the substrate on which the transfer layer was not provided is 40 n
m.

The thermal transfer recording material using this film produced wrinkles and burns during printing, although not as much as in Comparative Example 4.
The print quality was unusable.

[0133]

[Table 1]

In Table 1, the polymer compositions are as follows.

Composition 1: CPA / DPE / CTPC = 80
/ 20/100 Composition 2: DPX / DOB / DPE / TPC = 40/40
/ 20/100 Composition 3: DPX / DMB / 2,2'-dimethylbenzidine /
DPE / TPC = 35/30/20/15/100 Composition 4: CPA / DPE / CTPC = 70/30/10
0 Composition 5: MA / IPC / TPC = 100/50/50 Composition 6: CPA / DPE / CTPC = 60/40/10
0

[0136]

According to the present invention, since the Young's modulus in the longitudinal direction is increased, the rigidity required for thinning the recording medium is maintained, and the thermal dimensional behavior in all directions is less than a specified value. By suppressing the change spots, wrinkles and breaks, which are particularly noticeable in widening, do not occur, and high-definition printing quality can be realized.

The present invention is particularly suitable for recording using a thermal head. However, a heating means for the thermal transfer layer other than the thermal head, for example, a thermal printing plate, a laser beam, heat generation in a base film, or the like. It can also be used for a recording method using such means.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // B29K 77:00 B29L 7:00

Claims (7)

[Claims] 1. A transfer material for thermal recording comprising a heat-sensitive transfer layer provided on one surface of a base film made of an aromatic polyamide, wherein the base film has a Young's modulus in a longitudinal direction at 20 ° C. and a relative humidity of 60%. EMD is 6.86 GPa or more,
The transfer material for heat-sensitive recording, wherein the base film is a film that maintains a substantially flat surface after a heat treatment at 200 ° C. for 10 minutes. 2. The method according to claim 1, wherein the base film is 10 ° C. at 200 ° C.
The transfer material for heat-sensitive recording according to claim 1, wherein a dimensional change rate after a heat treatment for 2 minutes is 2% or less. 3. A molecular weight of 100 contained in the base film.
3. The transfer material according to claim 1, wherein the weight fraction of the oligomer having a value of 0 or less is 0.5% by weight or less. 4. The method according to claim 1, wherein when the weight average molecular weight of the aromatic polyamide constituting the base film is Mw and the number average molecular weight is Mn, the following formula is satisfied. Transfer material for thermal recording. Mw / Mn ≦ 4.5 5. The substrate film at 20 ° C. and a relative humidity of 60%.
The transfer material for heat-sensitive recording according to any one of claims 1 to 4, wherein the following expression is satisfied when the Young's modulus in the width direction is set to ETD. EMD ≧ ETD × 1.1 ETD ≧ 6.86 GPa 6. A heat-sensitive transfer layer having a width of not less than 100 mm and a sublimation type heat-sensitive transfer layer.
6. The transfer material for thermal recording according to any one of items 1 to 5. 7. A film obtained by discharging a solvent solution of an aromatic polyamide from a die and casting it on a support, subjecting it to dry heat and / or wet heat as needed, extracting the solvent and heat fixing. In order to obtain a thermal transfer material by providing a thermal transfer layer on the obtained film, the temperature difference between any two points in the vicinity of the die discharge portion is controlled to 10 ° C. or less and / or the discharge thickness unevenness is reduced to 10 ° C. % And controlling the temperature and / or water vapor content in the vicinity of the film in the processing tank to 5% or less in the width direction of the base film when performing the treatment under dry heat or wet heat. Process,
When processing in a liquid medium, the medium is brought into contact with the film surface with a flow, and a means for removing the adhered medium from the outlet of the processing tank to the drying and heat fixing step is used. Transfer material manufacturing method.