JP2525399B2 - Transferr for thermal recording - Google Patents

Description

The present invention relates to a heat-sensitive recording transfer member used in a thermal printer or the like for recording by thermal fusion transfer or sublimation transfer.

[Prior Art] A thermal recording transfer member used for recording of a color material transfer method by applying heat is basically composed of a base film and a thermal transfer layer. The base film is a polyester film. The heat-sensitive transfer layer is made of a mixture of a dye or a pigment and a wax or a mixture of a sublimable dye and a binder resin depending on the transfer method. However, with the trend toward higher recording speed, higher print quality, and diversified color material selection, there is a demand for higher thermal heads and thinner base films. Due to the characteristics of, it is becoming difficult to respond sufficiently. From such a situation, for example, JP-A-61-86288 discloses that an aromatic polyamide film which is cheaper than a polyimide film is used, and the problem of sticking disappears even without a back coat layer, Further, it has been shown that providing a back coat layer is very effective for noise and durability of the thermal head.

[Problems to be Solved by the Invention] However, when printing is attempted at high temperature and high speed by utilizing the heat resistance of the aromatic polyamide, the problem of sticking is small without the back coat layer,
The film softens and is scraped by the head, resulting in poor image quality. Further, when the back coat layer is provided, the number of steps is increased, which leads to an increase in cost. Further, a polyhydric alcohol polymer compound or an isocyanate compound is generally used as a binder for the back coat layer, but it is a different substance from the aromatic polyamide and its adhesive strength is limited. As a result, under hard operating conditions, the back coat layer may fall off and the head may become clogged, resulting in a reduction in image quality and a reduction in sensitivity.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal recording transfer member using a laminated film of an aromatic polyamide, which does not require a back coat layer, as a base material in order to solve the above problems.

[Means for Solving Problems] In the present invention, an aromatic polyamide layer (A) having a surface roughness of 0.1 μm or less and a glossiness of 400 or more, and an aromatic polyamide layer (B) having a surface roughness of 0.12 to 1.0 μm. And a thermal transfer layer provided on the aromatic polyamide layer (A) side surface of a laminate having a Young's modulus of 100 kg / mm ² or more at 200 ° C. Is.

The aromatic polyamide layer of the present invention means a basic structural unit (HN
-Ar ₁ -NHOC-Ar ₂ -CO) a is made of a polymer containing more than 50 mol%. Here, Ar ₁ and Ar ₂ are the following (1),
It has the structure of (2).

(1) Ar ₁ : Here, R and X are halogen groups, nitro groups, C _{1 to} C ₃ alkyl groups, C _{1 to} C ₃ alkoxy groups, and Y is _{-CH 2 -, - O -,} - SO 2 -.

p, m, and n are 0 to 3, and l is 0 or 1.

(2) Ar ₂ : Here, S is a halogen group, a nitro group, an alkyl group of C ₁ -C _3, alkoxy group of C ₁ -C _3, q is 0-4.

Among these, polymers having a substituent such as halogen (especially chlorine) or alkyl group (especially methyl group) in R and S,
Alternatively, a polymer having an alkyl group or —CH ₂ — in X or Y is preferable because it has improved humidity characteristics as compared with a polymer having no substituent.
For example, Polymers containing 50 mol% or more of such compounds are listed. This aromatic polyamide is obtained by the reaction of acid chloride and diamine or the reaction of isocyanate and carboxylic acid.

Taking the combination of an acid chloride and a diamine as an example, as a monomer, the acid chloride side has terephthalic acid chloride, isophthalic acid chloride, and those having halogen, nitro, alkyl, or alkoxy groups in their aromatic nuclei, Examples thereof include 2-chloroterephthalic acid chloride, 2-chloroisophthalic acid chloride, 2,5-dichloroterephthalic acid chloride, 2-nitroterephthalic acid chloride and 2-methylisophthalic acid chloride. The diamine side is p
-Phenylenediamine, m-phenylenediamine, 4,
4'-diaminodiphenyl ketone, 3,3'-dianodiphenyl ketone, 4,4'-diaminodiphenylmethane, 3,4 '
-Diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,
3'-diaminodiphenyl ether, benzidine, and those having the above-mentioned substituents on their aromatic nuclei, for example, 2-chloro-p-phenylenediamine, 2-chloro-metaphenylenediamine, 2-methyl-metaphenylenediamine, 3 , 3'-dimethylbenzidine, etc.

Taking the combination of isocyanate and carboxylic acid as an example, the isocyanate side is phenylene-1,4-diisocyanate, phenylene-1,3-diisocyanate, diphenylketone-4,4'-diisocyanate, diphenylmethane-4,4'- Diisocyanate, diphenyl ether-4,4'-diisocyanate, diphenyl sulfone-
4,4'-diisocyanate, and those having the above-mentioned substituents in these aromatic nuclei, for example, toluylene-2,6-
Examples include diisocyanate and toluylene-2,4-diisocyanate. On the carboxylic acid side, there are terephthalic acid, isophthalic acid, and those having the above-mentioned substituents on their aromatic nuclei.

The present invention requires that the basic structural unit represented by the above general formula is contained in an amount of 50 mol% or more, preferably 70 mol% or more. If the amount is less than the above range, it becomes impossible to form a film having sufficient mechanical properties, and the heat resistance is lowered, so that the object of the present invention cannot be achieved. The copolymerization component of less than 50 mol% is not particularly limited and may contain an ester bond, a urethane bond, an imide bond, a heterocyclic bond or the like. In order to obtain a film with excellent mechanical properties and heat resistance, the polymer has an intrinsic viscosity (0.5 g of polymer).
1 with N-methylpyrrolidone containing 2.5 wt% lithium bromide
The value measured at 30 ° C. as a 00 ml solution) is preferably 0.5 to 6.0.

Further, the aromatic polyamide of the present invention may be blended with a lubricant, an antioxidant, other additives and the like, or another polymer, to the extent that the physical properties of the film are not impaired.

The layers A and B of the present invention are preferably polymers having the same structure, but they may be different.

In the film of the present invention, the surface roughness of the A layer (the surface is referred to as the A surface) on the side where the heat-sensitive transfer layer is provided needs to be 0.1 μ or less and the surface glossiness to be 400 or more. The glossiness is preferably 500 or more. Greater than 0.1μ or 400 gloss
When it is less than the above range, the surface property of the A side is deteriorated and the surface of the transfer layer is roughened, resulting in deterioration of image quality.

Further, the B layer on the side in contact with the head (the surface is called the B surface)
The surface roughness of 0.12 to 1.0 μm is required. Preferably 0.1
It is 5 to 0.5 μ. If it is less than 0.12, the friction with the head becomes large and sticking occurs or the film is scraped to cause clogging of the head and deteriorate the image quality. If it is larger than 1.0 μ, the contact with the head becomes poor and, as a result, the heat transfer becomes poor and the sensitivity decreases, making it impossible to increase the speed. Further, when the film is pressed by the head, deformation in the thickness direction of the film is caused to deteriorate the surface on the transfer layer side and deteriorate the image quality.

A more preferable aspect of the surface roughness of the A surface and the B surface is that the B surface is
0.15μ ~ 0.5μ, A side is 0.08μ or less and gloss is 500
This is the case. By designing the surface in this way, the friction with the head is small even without the back coat layer, so that sticking or scraping does not occur even in hard use. Further, since the side A is smooth, the density with the image receiving paper is good, and good transfer occurs, so that very excellent image quality can be obtained.

Further, the film of the present invention has a Young's modulus at 200 ° C. in at least one direction of 100 kg / mm ² or more, preferably 150 kg / mm ²
That is all. If it is less than 100 kg / mm ² , when the film is pressed by a high temperature head, deformation of the film in the thickness direction easily occurs and the roughness of the B side affects the A side as well.
As a result, the image quality is deteriorated. In addition, the film may be easily deformed in the surface direction, and wrinkles may occur, resulting in deterioration of the image quality and obstruction of winding.

Further, the thickness of the film is preferably 1 to 15 μ, more preferably 2 to 10 μ. If it is thinner than 1 μm, the strength is lowered and it cannot be used practically. If it is thicker than 15 μm, the heat transfer is deteriorated and the speed cannot be increased, or the large heat diffusion makes it impossible to perform local heating and clear image quality cannot be obtained.

The film of the present invention preferably has a strength in at least one direction of the longitudinal direction or the width direction of 8 kg / mm ² or more, more preferably 10 kg / mm ² or more. Further, the elongation is preferably 10% or more, more preferably 15 to 100%, and the dimensional change rate under a load of 1 kg / mm ² is preferably 5% or less at 200 ° C., and 2% or less. Is more preferable.

The moisture absorption rate of the film is preferably 5% or less, and 4%.
The following is particularly preferable. This is because when the moisture absorption rate of the film is large, the film foams when the transfer body is heated by the thermal head, and the transfer of the ink becomes non-uniform, resulting in a problem that the image quality is deteriorated.

The tear transfer resistance of the film is preferably 100 g / mm or more in order to prevent the film from breaking during use in the thermal transfer recording apparatus.

Next, the heat-sensitive transfer layer in the present invention is a layer formed by applying a heat-sensitive transfer ink such as heat-meltable ink or heat-sublimable ink to a film. The thermal transfer ink is mainly composed of a coloring component and a binder component, and if necessary, a softening agent,
A flexible agent, a smoothing agent, a dispersant, a surface forming agent and the like are used as additional components. The thickness of the thermal transfer layer is, for example, 0.2 to 20.
μ, preferably 0.5 to 10 μ.

Well-known waxes such as carnauba wax, paraffin wax, and ester wax, cellulosic resins, vinyl resins, and various low melting point polymers are useful as the binder component, and carbon black and various types of coloring components are useful. Organic or inorganic pigments or dyes are used.

Next, a method of manufacturing the thermal recording transfer member of the present invention will be described.

The aromatic polyamide film is generally formed by a solution casting method from a polymer solution in which an aromatic polyamide resin is dissolved in an organic solvent.

The polymer is prepared by polymerizing a monomer in an organic solvent such as N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), hexamethylphosphoramide (HMPA), dimethylformamide (DMF), tetramethylurea and γ-butyrolactone. Polymerization is carried out by a solution polymerization method performed by addition, an interfacial polymerization method using an aqueous medium, or the like. Further, particularly when polymerizing from diisocyanate and dicarboxylic acid, an amine catalyst may be added in some cases.

The polymer solution after polymerization is used as a stock solution for film formation, or when the polymer is put into water or the like to be reprecipitated and isolated, dried and then dissolved again in an organic solvent to prepare a stock solution for film formation. There is.

When the polymer solution after polymerization is used as it is as a stock solution for film formation, when acid chloride and diamine are used as monomers, it is necessary to neutralize the hydrogen halide produced as a by-product during polymerization.

When an inorganic base or the like is used at the time of neutralization, lithium chloride, calcium chloride or the like is produced as a neutralizing salt, and these inorganic salts act as a solubilizing agent for the polymer. For the same reason as above, when the polymer is isolated and redissolved in an organic solvent after the above-mentioned polymerization, an alkali or alkaline earth metal halide such as the above inorganic salt may be added. The ratio of the inorganic salt to the polymer is preferably 150 mol% or less with respect to the amide group of the polymer in the stock solution for film formation.

When the prepared stock solution for film formation contains a neutralizing salt or an inorganic salt as a dissolution aid, it is preferable to form a film by a wet method or a dry-wet method.

In the wet method, the stock solution for film formation is extruded directly from the die into a coagulation bath, or once cast on a support such as a drum or belt,
A method of introducing the whole support into the bath is adopted. This coagulation method generally comprises an aqueous medium, but in some cases, an organic solvent, an inorganic salt or the like is mixed in addition to water. In the coagulation bath, the organic solvent, inorganic salt, etc. in the stock solution for film formation are extracted to form a gel film containing water. The gel film is then dried in a tenter or the like and heat treated to give the final film.

In the dry-wet method, the stock solution for film formation is cast from a spinneret onto a support such as a drum or an endless belt, and heated by hot air to evaporate the solvent until the stock solution becomes a gel film with self-retaining properties. After drying, the gel film is peeled off from the support. At this time, it is necessary to adjust so that the solvent does not evaporate rapidly from the surface.
Drying conditions are set within 60 minutes at ℃. The gel film that has undergone the dry process is subjected to extraction of the solvent and salt in a water-based bath as in the wet method, and then dried and heat-treated in a tenter to obtain the final film.

Depending on the basic structural unit of the polymer or the kind of the monomer, a stock solution for film formation containing no inorganic salt can be prepared, and in this case, the film can be formed by a dry method. The dry method is a method in which extraction of water such as a solvent in the dry-wet method is omitted, and an organic solvent is evaporated by heating to obtain a final film.

The film molded by the above method, during the film forming process,
Stretching and heat treatment are carried out, specifically, the stretching ratio is 0.9 to 15 times in terms of areal magnification (the areal magnification is a value obtained by dividing the film area after stretching by the film area before stretching, where 1 .
A value less than 0 means shrinkage), heat treatment is 250 ℃ ~ 400
The temperature is 0.1 second to 30 minutes, and a good aromatic polyamide film can be obtained by setting the stretching and heat treatment conditions according to the basic constitutional unit of the polymer.

In order to form the laminated film of the present invention, two types of stock solutions, a stock solution for film formation corresponding to the A layer side and a stock solution for film formation corresponding to the B layer side, are prepared by known methods, for example, as disclosed in JP-A-56-162617. Can be laminated with a confluent pipe or can be formed by laminating in a die. It is also possible to form a film having a self-holding property with one of the stock solutions for film formation, and then cast the other stock solution for film formation to remove the solvent to obtain a laminated film. . Thickness ratio of A layer and B layer is A layer / B layer = 0.
It is preferable to adjust in the range of 1-10. More preferably, it is 0.5-2.

In order to make the surface roughness of the B side of the film within the range of the present invention, particles are dispersed in the stock solution for film formation. Here, the particles are not particularly limited, but SiO ₂ , TiO ₂ , ZnO, Al ₂ O ₃ , Ca
SO ₄ , BaSO ₄ , CaCO ₃ , carbon black, zeolite,
Inorganic and organic particles such as silicone particles and Teflon particles are used. The particle size is preferably 20mμ to 10μ, and the addition amount is 0.1 to 80wt% per polymer, and more preferably 0.1μ to 5μ.
Particles can be added in the range of 1 to 40 wt%.

Further, in order to bring the surface condition of the A side into the range of the present invention, the particles as described above may be dispersed in the stock solution for film formation on the A layer side, but in order to make it smoother than the B side, the B layer side. The particles may be smaller than the above particles, or may be added in a small amount, or may be added in a small amount. The preferred range is 20 mμ ~
5μ, the addition amount is less than 5wt%, more preferably less than 1%. Further, particles may not be added to the layer A side unless there is a problem in workability, running property, etc. at the time of manufacturing the heat-sensitive transfer member or printing with a printer.

Next, a heat-sensitive transfer layer is formed on the surface A of the base film of the present invention obtained as described above, but the film may be subjected to a pretreatment such as corona treatment or glow treatment, if necessary. There are the above-mentioned thermal transfer inks, which can be hot-melt coated on one side of the film, or can be formed as a solution dissolved in a solvent by a general-purpose coating method such as gravure, reverse, or slit die. it can.

EFFECTS OF THE INVENTION The transfer material for heat-sensitive recording of the present invention has a low friction with the head because the surface on the head side is roughened, and the entire base resin is made of aromatic polyamide. Since there is no need to worry about layer detachment as when applying a coat layer, the heat resistance of aromatic polyamide is utilized to prevent film scraping and sticking even when used hard at high temperatures, and to prevent head loss. Durability and image quality can be dramatically improved. Further, since it is not necessary to provide a back coat layer, the transfer body preparation process can be simplified and the cost of the transfer body can be reduced.

Further, since the surface of the film on which the transfer layer is provided is smooth, it has good adhesion to the image receiving paper, good transfer occurs, and very excellent image quality is obtained.

[Characteristics Measurement Method] (1) Surface Roughness Using a SE-3E surface roughness measuring instrument manufactured by Kosaka Laboratory, a measurement length of 4 mm was measured under the condition of a cutoff value of 0.08 mm, and expressed by the center line average roughness. . The film is set in a glass cylinder with an outer diameter of 80 mm and measured.

(2) Glossiness Using a variable angle gloss meter VG-107 type manufactured by Nippon Denshoku Industries,
Evaporate 1000 to 1500Å aluminum and measure at an angle of 60 °. The mirror gloss varies slightly with the thickness of the glass, but is around 800.

(3) Young's modulus The film is set in a Tensilon tensile tester so that the test width is 10 mm and the test length is 50 mm, and the film is pulled at a pulling speed of 300 mm / min for measurement.

[Examples] The present invention will be described below based on Examples. However, the present invention is not limited to these examples.

Example 1 70% by mol of 2-chloroparaphenylenediamine and 4,4 '
-Diaminodiphenyl sulfone 30 mol% as an amine component, terephthalic acid chloride 100 mol% as an acid component NMP
Polymerization was carried out in and neutralized with lithium hydroxide to obtain a polymer solution. Intrinsic viscosity is 2.5. Divide this into two, N in advance
2μ of silica dispersed in MP was added to the polymer solution forming the A layer at 0.2wt% per polymer, and to the polymer solution forming the B layer at 6wt% per polymer, and both polymer solutions were added at 30 ° C. It was adjusted to 3000 poises to prepare a stock solution for film formation.

These stock solutions were laminated into two layers in the mouthpiece so that the A and B layers were both 3μ in thickness, further cast on a metal drum, and dried for 10 minutes in an atmosphere of 120 ° C for self-holding property. A gel film having This gel film was continuously peeled off from the drum and introduced into a water tank for desolvation and desalting, followed by drying of water and heat treatment in a tenter to obtain a final film of 6 μm. During this time, the film is stretched 1.3 times in the longitudinal direction in a water tank and 1.3 times in the width direction in a tenter, and the heat treatment condition is 300 ° C. for 2 minutes.

As shown in Table 1, the characteristics of the obtained film were such that the B side was roughened and the A side was smooth and had good gloss. The Young's modulus at high temperature was also high.

The surface A of this film was coated with three types of sublimable dyes of yellow, cyan and magenta dissolved in a binder and a solvent having the following compositions to obtain a three-color transfer sheet. The thickness of each transfer layer after drying is 2 μm.

Dye 5 parts Cellulose resin 5 parts Toluene 40 parts Methyl ethyl ketone 40 parts Isobutyl alcohol 10 parts This transfer sheet was brought into close contact with an image receiving paper and heated by a thermal head for printing. By printing three colors in succession, a full-color printed matter of very good image quality was obtained. The head density is 6 lines / mm, and the maximum applied pulse width is 1
It is 0 msec, and the head temperature measured under this condition is 350 ° C.
Met.

At the time of printing, it was confirmed that the transfer sheet had a smooth running property, there were no wrinkles and stick noises on the sheet, and there was no scraping or scratches on the B side, which was a very good transfer sheet.

Example 2 Polymerization was carried out in NMP using metaphenylenediamine as an amine component and isophthalic acid chloride as an acid component, and further neutralized with calcium hydroxide to obtain a polymer solution. This was divided into two and the same silica as in Example 1 was added to the A layer side so that 1 wt% per polymer and the B layer side was added at 10 wt%.
A 0 poise stock solution for film formation was obtained.

These were laminated in a die so that the A layer was 4 μm and the B layer was 2 μm, and a 6 μm film was obtained through the same steps as in Example 1. Stretching is 3 times in the longitudinal and width directions, and heat treatment is 300
C., 2 minutes.

Further, when the same dye as in Example 1 was coated on this and printed, a slightly rougher feeling than in Example 1 was obtained, but a good printed matter without print omission or scratches was obtained.
In addition, the transfer sheet had no problems with running property, wrinkles, stick noise, scraping and scratches.

Example 3 70 mol% 2-chloroparaphenylenediamine and 4,4 '
Polymerization was carried out in NMP using 30 mol% of diaminodiphenyl ether as an amine component and 100 mol% of 2-chloroterephthalic acid chloride as an acid component, and neutralized with lithium hydroxide to obtain a polymer solution. Intrinsic viscosity is 2.8. This is divided into two and 2 μ of silica is added to the polymer solution on the layer A side in an amount of 0.1 per polymer.
3wt%, 2μ Teflon particles were added to the polymer solution on the layer B side at 10wt% per polymer, and both solutions were added at 4000 at 30 ℃.
Poise prepared.

These are 3μ for both the A and B layers in the final film in the die.
And a film having a thickness of 6 μm were obtained through the same steps as in Example 1. Stretching is 1.4 times in the longitudinal and width directions, and heat treatment is at 300 ° C. for 3 minutes.

Further, the same dye as in Example 1 was coated on this and printing was performed, and a printed matter having a very excellent full-color gradation was obtained. There were no wrinkles or sticking sounds on the sheet, and there was no scratch or scratch on the B side.

Comparative Example 1 A 6 μ film was prepared in the same manner as in Example 1 except that no particles were added to the A layer side and 0.2 μ% of 2 μ silica was added to the B layer side. Created. The characteristics of this film are shown in Table 1, and the smoothness is excellent on both sides A and B.

When this was coated with a dye in the same manner as in Example 1 and printed, the image quality of the first sheet was very good, but sticking noise was slightly generated. Further, when the same head was used for printing, linear streaks began to appear in the printed matter, and when printing was continued, some areas were not printed. When the surface B of the transfer sheet was observed, many scratches were generated, and many foreign matters scraped off from the film adhered to the surface of the thermal head. It is considered that since the surface B was too smooth, the friction with the head was great and the film was scraped.

Comparative Example 2 Contrary to Comparative Example 1, the polymer was the same as in Example 1 except that 8 wt% of silica was added to the A layer side and 12 wt% of silica was added to the B layer side to form a 6 μ film. The characteristics of the film are shown in Table 1, and the A side is a film that is considerably roughened and has a low glossiness. When this was coated with the dye of Example 1 and printed, the printed matter had poor definition. The B side of the film was not scratched or scratched.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-60-247584 (JP, A) JP-A-59-101394 (JP, A) JP-A-55-7467 (JP, A) JP-A-60- 174694 (JP, A) JP 61-92893 (JP, A) JP 62-37191 (JP, A) JP 62-23789 (JP, A) JP 63-107588 (JP, A)

Claims (1)

(57) [Claims] 1. An aromatic polyamide layer (A) having a surface roughness of 0.1 μm or less and a glossiness of 400 or more and an aromatic polyamide layer (B) having a surface roughness of 0.12 to 1.0 μm, and having a Young's modulus at 200 ° C. A transfer material for heat-sensitive recording comprising a heat-sensitive transfer layer provided on the surface of the laminate having an aromatic polyamide layer (A) of 100 kg / mm ² or more.