JP3218660B2 - Image receiving sheet for thermal transfer recording - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving sheet for thermal transfer recording and, more particularly, to an improvement in an image receiving sheet for thermal transfer recording using a thermo-sublimable dye. Is provided.

[0002]

2. Description of the Related Art A thermal recording system in which a recorded image is obtained simultaneously with an input signal is used in various fields such as a facsimile, a terminal printer for a computer, and a printer for a measuring instrument because the apparatus is relatively simple, inexpensive and has low noise. Have been. As a recording medium used in these thermal recording systems, a so-called color-developing type thermosensitive recording paper provided with a recording layer that causes a physical or chemical change by heating to form a color is most commonly used.

[0003] However, the color-sensitive type thermosensitive recording paper is liable to cause unnecessary color development during the manufacturing process and during storage, is also inferior in storage stability of the recorded image, and is not in contact with organic solvents and chemicals. There is a disadvantage that the discoloration phenomenon easily occurs. For this reason, a method using a recording medium using a colored material itself has been proposed as a recording medium in place of the coloring type thermosensitive recording paper.
Japanese Patent No. 15446 discloses a thermal recording method in which a color material which is solid or semi-solid at room temperature is applied to a support such as paper or a polymer film, and the color material on the support is brought into contact with recording paper. A method has been proposed in which a color material on a support is heated by a head and selectively transferred to recording paper to obtain a recorded image.

In this recording method, a coloring material on a support is melted, evaporated and sublimated by heat, transferred to a recording paper to obtain a recorded image by adhesion, adsorption and dyeing. There are features available. In particular, in a recording method using a sublimable dye as a coloring material, an image with excellent gradation can be obtained, and therefore, application development for full-color recording has been promoted.

However, when plain paper is used as recording paper, it is difficult for dyeing to occur, sufficient color density is not obtained, and a remarkable fading phenomenon occurs with the passage of time. Therefore, Japanese Patent Application Laid-Open No. 57-107885 and US Pat.
JP-A-601484 and the like have proposed an image-receiving sheet having an image-receiving layer containing a thermoplastic resin as a main component. By forming an image receiving layer mainly containing a thermoplastic resin,
Although the recording sensitivity and storage stability are improved for the time being, a uniform image-receiving layer cannot be obtained particularly when the support is plain paper, and both the recording sensitivity and the image quality are insufficient. Therefore, Japanese Patent Application Laid-Open No. 60-23 / 1985
No. 6,794, JP-A-61-144394, etc., an intermediate layer such as a thermoplastic resin is interposed between the support and the image receiving layer, and the color material layer of the color material transfer sheet is used for printing. A method has been proposed in which the adhesion between the sheet and the image receiving layer of the image receiving sheet is improved so that an air gap or the like does not occur, and both the recording sensitivity and the image quality are improved.

The intermediate layer is made of a specific thermoplastic resin (JP-A-60-236794, JP-A-61-1443).
No. 94, No. 61-258793, No. 61-29508
No. 5) or composed of specific resin fine particles (Japanese Unexamined Patent Publication No.
Nos. 87286 and 64-27996, JP-A-1-13
Nos. 6784 and 2-139293), and it has been proposed to further improve the image quality and / or the recording sensitivity, but in reality, satisfactory results have not been obtained.

[0007] On the other hand, it has been proposed to obtain good image quality and recording sensitivity by using synthetic paper or white film as a support. However, deformation may occur due to heat applied at the time of recording, or the cost may be increased. However, there still remain problems such as the use of a suitable material, and it was not satisfactory.

[0008]

In view of this situation, the present inventors have made extensive studies on the improvement of an image-receiving sheet for thermal transfer recording, which is useful in a recording system for thermally transferring a colored coloring material, particularly a thermal sublimable dye. As a result, an image receiving sheet having extremely high recording sensitivity and providing a high-quality recorded image with excellent resolution, sharpness, color density, missing dots and the like has been completed.

[0009]

According to the present invention, there is provided an image receiving sheet for thermal transfer recording comprising an image receiving layer for receiving an image transferred from a color material transfer sheet on a support, wherein the support for the image receiving sheet is a plastic film. (Provided that there is no separable polyolefin layer on the surface of the support), and between the support and the image receiving layer, 18 to 80 mol% of the total monomer composition
An image receiving sheet for thermal transfer recording, wherein an intermediate layer containing a polyvinyl alcohol resin having a hydrophobic group is provided. Further, the present invention provides a thermal transfer recording image receiving sheet comprising an image receiving layer for receiving a transfer image from a color material transfer sheet on a support, wherein the support of the image receiving sheet is paper, and the support and the image receiving layer Between 40 and 40
An image receiving sheet for thermal transfer recording , comprising an intermediate layer containing a polyvinyl alcohol-based resin having a hydrophobic group content of up to 80 mol% and organic powders .

[0010]

The image receiving sheet for thermal transfer recording of the present invention is characterized by the composition of the intermediate layer, that is, a polyvinyl alcohol resin having a hydrophobic group in the intermediate layer in an amount of 18 to 80 mol% of the total monomer composition. Has an extremely significant significance in that is contained as an essential component. The thermal transfer recording image-receiving sheet thus obtained is excellent in recording sensitivity and can provide a high-quality recorded image which is extremely excellent in resolution, sharpness, color density, missing dots, and the like. Although the reason why such an effect is obtained is not always clear, the specific polyvinyl alcohol-based resin constituting the intermediate layer exerts its characteristics at the time of thermal transfer recording to uniformly control heat transfer from the recording head, It is presumed that this is to enhance the adhesion between the color material transfer sheet and the image receiving sheet.

In the thermal transfer recording image-receiving sheet of the present invention, the polyvinyl alcohol-based resin as an essential component constituting the intermediate layer is prepared by adding a fatty acid vinyl ester-based resin obtained by a conventional method to a required saponification degree. A method is generally used in which the remaining fatty acid vinyl ester unit is decomposed and the remaining fatty acid vinyl ester unit is used as a hydrophobic group.

For example, the polymerization of a fatty acid vinyl ester monomer represented by vinyl acetate can be carried out by a conventional method such as bulk polymerization, solution polymerization, emulsion polymerization, and granular polymerization. , Solution polymerization is preferably utilized, the choice of polymerization solvent, monomer and / or
Alternatively, the required degree of polymerization can be controlled by any method such as selection of the initiator concentration, selection of the polymerization temperature and / or polymerization time, and / or use of a chain transfer agent. The hydrolysis of the fatty acid vinyl ester-based resin obtained above can be carried out with an alkali catalyst or an acid catalyst. However, the hydrolysis reaction with an alkali catalyst is preferably used because there are few side reactions and the like. The required degree of saponification can be controlled by selecting the reaction temperature, reaction time and the like. Further, for example, the degree of saponification can be controlled by changing the water content at the time of hydrolysis in an alcohol-based solvent, which is preferably used.

In the present invention, a specific polyvinyl alcohol resin is used as an essential component of the intermediate layer. The physical properties of the coating liquid for forming the intermediate layer are controlled, and the whiteness and opacity of the obtained intermediate layer are controlled. Organic or inorganic powders can be used in combination for the purpose of controlling the smoothness, etc., and improving the workability of the web during and after the formation of the intermediate layer. Organic powders with particularly low thermal conductivity can be used. Are preferably used in combination. Examples of such organic powders include natural organic powders such as starch granules, cellulose powder, pollen, and condensation-based resin fine particles represented by nylon, polyester, urea, melamine, and guanamine, polyurethane, and the like. system,
Synthetic resin fine particles such as polyaddition resin fine particles typified by epoxy type and polymerized resin fine particles typified by vinyl type are preferably used.

Such synthetic resin fine particles can be prepared by a method utilizing morphogenesis accompanying the progress of polycondensation or condensation reaction in a solvent such as water, or by controlling an external force during resin production such as an emulsion polymerization method or a suspension polymerization method. Post-processing after resin formation, such as direct manufacturing, granulation in liquid in a non-solvent, and mechanical granulation such as freeze-drying, dry and / or wet granulation, etc. Can be obtained.

Among the resin fine particles as described above, vinyl resin particles can easily control physical properties by selecting a monomer, and can also easily produce fine particles.
These vinyl-based resin particles are synthesized by a so-called polymerization method by selecting one or more suitable monomers, but are preferably synthesized in the form of an aqueous dispersion by an emulsion polymerization method, a suspension polymerization method or the like. Specific examples of the monomer constituting the main component include, for example, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 4-methoxystyrene, vinyl chloride, vinylidene chloride, ethylene, vinylcyclohexane, methyl methacrylate, hexyl acrylate ,
Examples include vinyl monomers such as vinyl acetate and acrylonitrile. For example, a rubber-based monomer such as 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene is added, and the melting point, softening point, and glass of the resin particles are added. Conversely, the melting point, softening point, and glass transition point of the resin particles can be increased by lowering the transition point or by adding a crosslinking agent such as divinylbenzene.

In order to improve the surface characteristics of the resin particles, an α, β-ethylenically unsaturated carboxylic acid monomer such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, etc. is added and copolymerized. It can also be denatured by a polymer reaction or the like. Furthermore, it is also possible to modify into a so-called ionomer resin by metal crosslinking. In addition, these resin fine particles may be of any shape such as sphere, flat, confetti, snow daruma, wild strawberry, star, amorphous, etc., and can be used. However, spherical particles have a remarkable effect in the present invention. And is preferably used.

The inside of these spherical particles may be homogeneous, or may be particles having a heterogeneous structure such as a multilayer structure or a polynuclear structure. In addition, non-expandable hollow resin particles (for example, manufactured by Rohm and Haas Co., Ltd .; Ropaike, etc.) provided with internal voids during the production of such resin particles, are thermally foamed as needed, and contain a thermal expansion containing a foaming agent usable as hollow resin particles. Resin fine particles (for example, manufactured by Matsumoto Yushi Co., Ltd .; Microsphere, manufactured by Nippon Philite Co., Ltd., EXPANCEL, etc.), and further USP
As exemplified in US Pat. No. 4,722,943, a composite thermoplastic resin fine particle whose surface is coated with an inorganic powder is also preferably used.

Examples of the inorganic powder include clay, kaolin, calcined kaolin, delaminated kaolin, structural kaolin, aluminum hydroxide, titanium dioxide, barium sulfate, zinc oxide, satin white, talc, silica and the like. So-called inorganic pigments used in the field of coating are used, but are used within a range that does not impair the effects of the present invention.

Further, the coating liquid for forming an intermediate layer may be added, if necessary, with various binders for improving adhesiveness and fluidity, and dyes and pigments for controlling color tone, whiteness and the like. / Or addition of fluorescent dyes, addition of ultraviolet absorbers, antioxidants, etc. for improving storage stability, addition of dispersants, wetting agents, antifoaming agents, etc. for improving smear suitability, etc.
The addition of various auxiliary agents known in the art, such as a preservative, a fungicide, an antistatic agent, a water-proofing agent, a crosslinking agent, and the like, is also optional.

Examples of the binder include natural or semi-synthetic polymers such as modified starch, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, casein, gelatin, natural rubber; and polydienes such as polyvinyl alcohol, isoprene, neoprene and polybutadiene. , Polyalkenes such as polybutene, polyisobutylene, polypropylene and polyethylene, vinyl halide, vinyl acetate, styrene, (meth) acrylic acid,
Vinyl polymers and copolymers such as (meth) acrylate, (meth) acrylamide and methyl vinyl ether, polyesters, polyurethanes, polyamides, styrene-butadiene, methyl methacrylate
So-called coating binders such as synthetic polymers such as butadiene / maleic acid-based synthetic rubber latex and the like can be mentioned, and they are added as necessary, but compared to a specific polyvinyl alcohol-based resin which is an essential component of the present invention. In general, it is desirable to add 500% by weight or less.

By performing a smoothing treatment before or after forming the image receiving layer on the intermediate layer thus formed, the image quality and recording sensitivity of the obtained image receiving sheet can be further enhanced. The smoothing treatment is appropriately performed by, for example, heating and / or pressurizing treatment with a super calender, a gloss calender, a cast drum, or the like. It is effective, for example, when the average particle diameter of the resin fine particles is 0.1.
When the thickness is 1 μm or less, the effect of the smoothing treatment is small.
If it exceeds 00 μm, not only the suitability for coating but also the effect of the smoothing treatment cannot be expected. Therefore, it is desirable to use resin fine particles of 0.2 to 50 μm in combination. Although the amount of use cannot be unconditionally determined depending on the material, particle diameter, shape, etc. of the fine particles to be used, it is usually about 1/100 to 100/1, preferably 1/100, relative to the specific polyvinyl alcohol-based resin which is an essential component. It is desirable to use them together in the range of 20 to 20/1.

In the image receiving sheet of the present invention, the image receiving layer provided on the above-mentioned intermediate layer is not particularly limited, but a thermoplastic resin layer having an effective dyeing ability for a sublimable dye is generally preferable. Used. Examples of the thermoplastic resin constituting the image receiving layer include polymers and copolymers of vinyl monomers such as styrene, vinyl toluene, acrylic ester, methacrylic ester, acrylonitrile, vinyl chloride, and vinyl acetate; polyester,
Condensation polymers such as polyamide, polycarbonate, polysulfone, epoxy resin and polyurethane; and cellulose resins. These thermoplastic resins may be used alone, or two or more resins having different properties may be used in combination.

If necessary, methylcellulose, ethylcellulose, hydroxypropylcellulose, starch, polyvinyl alcohol, polyamide resin, phenol resin, melamine resin, urea resin, urethane resin, epoxy resin, silicone resin, fluorine resin, etc. May be contained, a polyvalent isocyanate compound,
It is also possible to modify the image receiving layer by adding a reactive compound such as an epoxy compound or an organometallic compound. But,
It is necessary to keep the thermoplastic synthetic resin constituting the image receiving layer within a range where the thermoplasticity is not lost.

Further, for the purpose of improving writability, for example, heavy and light calcium carbonate, talc, clay, natural and synthetic silicic acids, titanium oxide, aluminum hydroxide, zinc oxide, urea formaldehyde resin powder and the like are used in the image receiving layer. And various auxiliaries such as an inorganic or organic pigment, an ultraviolet absorber, an antioxidant, an antistatic agent, a release agent, and a lubricant.

The coating amount of the components forming the image receiving layer on the intermediate layer is appropriately selected according to the purpose of use of the image receiving sheet, etc., and generally, about ² to 15 g / m ^{2 by} dry weight. Will be constructed. As the support, plain paper, synthetic paper, synthetic resin film or the like is appropriately selected and used, but plain paper is preferably used because of its excellent thermal characteristics. The plain paper referred to here is, for example, a paper obtained by ordinary papermaking mainly containing cellulose pulp and adding a paper strength enhancer, a sizing agent, a fixing agent, an inorganic or organic filler, and the like. Includes paper whose surface properties have been improved by size-pressing oxidized starch or the like, or providing a pre-coat layer containing a pigment as a main component such as clay, etc., but the surface is smooth such as art paper, coated paper, cast-coated paper, etc. Paper having excellent properties is particularly preferably used.

These supports can be provided with an image receiving layer after the formation of the intermediate layer. If necessary, before and / or after the formation of the intermediate layer, control of adhesiveness, barrier property, smoothness, concealing property, smear suitability and the like can be performed. For the purpose, it is optional to further provide an anchor coat layer or to extrude and laminate or bond the thin film base material, and known materials and methods can be used.

On the image receiving layer, for example, JP-A-59
As disclosed in JP-A-165688 and JP-A-61-27290, a thin heat-resistant release layer mainly composed of a silicon-based resin having a property of transmitting a sublimation dye is formed. It is also possible to prevent the dye or the dye layer from directly transferring from the color material transfer sheet. Further, in order to improve the suitability for handling and / or the suitability for a printer of the obtained image transfer sheet for thermal transfer recording, for example, a back coat layer is provided for the purpose of, for example, curling prevention, slip control, imparting writability, Apply antistatic treatment to the front and / or back, etc.
It is optional to perform the treatment by a conventional method in the art.

The heat sublimable dye referred to in the present invention does not cause the transfer of the coloring material even when it comes into contact with the image receiving sheet under normal handling conditions. Means a dye that causes a transition of the coloring material by the like, for example, azo-based, nitro-based, anthraquinone-based, quinoline-based disperse dyes, triphenylmethane-based, fluoran-based basic dyes, It is used by appropriately selecting from various dyes such as oil-soluble dyes.

The thermal transfer recording image receiving sheet of the present invention thus obtained exhibits extremely excellent performance as an image receiving sheet particularly when a sheet containing a thermosublimable dye is used as a color material transfer sheet. It is excellent in recording sensitivity and can provide a high-quality recorded image which is extremely excellent in resolution, sharpness, color density, missing dots, and the like.

The image receiving sheet for thermal transfer recording according to the present invention is not limited to a thermal recording method of contact heating with a hot plate such as a thermal printing unit or a thermal head, but also a heat ray such as an infrared lamp, a YAG laser or a carbon dioxide laser. It is also useful for thermal recording by a non-contact heating method using radiation.

Hereinafter, the present invention will be described more specifically with reference to examples, but it is needless to say that the present invention is not limited to these examples. Unless otherwise specified, parts and% in the examples represent "parts by weight" and "% by weight", respectively.

Examples Examples 1 to 5 and Comparative Examples 1 to 4 [ Preparation of Intermediate Layer] As shown in Table 1, benzoguanamine resin powder (trade name) was added to various polyvinyl alcohol-based resin solutions having a vinyl acetate unit as a hydrophobic group. : Eposter MS, spherical, average particle diameter 2 μm, manufactured by Nippon Shokubai Co., Ltd.)
A coating solution for the intermediate layer is prepared by mixing, and the dry weight is 7 g / m ² on a commercially available high-quality paper (trade name: TKP-13, basis weight 81 g / m ² , manufactured by Kanzaki Paper Co., Ltd.). The coating was dried.

[0033]

[Table 1]

[Preparation of Image Receiving Layer] Next, an aqueous polyester resin (trade name: Vironal MD-1200, solid component 34)
%, Manufactured by Toyobo Co., Ltd.) on the intermediate layer with a dry weight of 4 g /
m ² after coating and drying to form an image receiving layer,
A smoothing treatment (linear pressure: 200 kg / cm) was performed using a super calender composed of a mirror-finished metal roll and an elastic roll. Next, a saturated polyester resin (trade name: Byron 2)
00, Toyobo Co., Ltd.) 100 parts, amino-modified silicone oil (trade name: KF-393, Shin-Etsu Silicone Co., Ltd.) 1.5
Part, epoxy-modified silicone oil (trade name: X-22-34
3, Shin-Etsu Silicone Co., Ltd.) 1.5 parts were added to methyl ethyl ketone / toluene (weight ratio 1/1) while stirring with a mixer, mixed and dissolved to prepare a coating solution. After applying and drying ² g / m ^{2 by} dry weight, 2 g at 100 ° C.
After heat-curing for 5 minutes, an image receiving sheet for thermal transfer recording was obtained.

Comparative Example 5 An image-receiving sheet for thermal transfer recording was obtained in the same manner as in Comparative Example 1 , except that no intermediate layer was provided.

The ten types of thermal transfer recording image-receiving sheets thus obtained were subjected to a quality comparison test as follows.
Table 2 shows the results.

[Quality Comparison Test] A commercially available color material transfer sheet (for the Hitachi printer VY-P1: magenta color portion) and the coated surface of the image receiving sheet for thermal transfer recording were overlapped, and heat was applied from the back of the color material transfer sheet using a thermal head. (12V, 4
(.About.16 msec), a thermal transfer recording image was formed on the image receiving layer surface of the image receiving sheet, and the recording density and image quality of each image receiving sheet and recorded image were evaluated as follows.

[Recording Density] The recording density was measured with a Macbeth densitometer (RD-914). [Image Quality] The image in the highlight area (7 ms) was observed with a 25-power loupe to evaluate dot reproducibility and dot omission. [Evaluation Criteria] A: There is no dot missing and the dot reproducibility is particularly excellent. B: There is no dot omission and dot reproducibility is excellent. C: Although there is a little dot omission, dot reproducibility is at a practical level. D: Missing dots are conspicuous, and there is a problem in practicality. E: Both dot missing and reproducibility were poor, and there was no practicality.

[0039]

[Table 2]

Example 6 [ Preparation of Intermediate Layer] 20 parts of a polyvinyl alcohol resin (trade name: SMR10M, hydrophobic group content: 40 mol%, manufactured by Shin-Etsu Chemical Co., Ltd.)
A dispersion liquid of an intermediate layer obtained by dispersing and dissolving in a mixed solvent consisting of 0 parts and 60 parts of isopropyl alcohol was coated on a commercially available white polyester film having fine pores (trade name: W-900E).
, Film thickness: 75 μm, manufactured by Diafoil Co., Ltd.) and dried to a dry weight of 10 g / m ² .

[Preparation of Image Receiving Layer] Then, in a mixed solvent consisting of 40 parts of methyl ethyl ketone, 40 parts of toluene and 20 parts of cyclohexanone, a vinyl chloride / vinyl acetate copolymer (trade name:
Dissolve 10 parts of ESREC A, Sekisui Chemical Co., Ltd.) and 10 parts of polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd.), and further amino-modified silicone oil (trade name: KF)
-393, Shin-Etsu Chemical Co., Ltd.) 0.3 parts, Epoxy-modified silicone oil (trade name: X-33-343, Shin-Etsu Chemical Co., Ltd.)
0.3 part was added to prepare a coating solution for an image receiving layer. The thus-obtained image-receiving layer coating liquid was applied onto the above-mentioned intermediate layer so as to have a dry weight of 5 g / m ² , dried and heated and cured at 120 ° C. for 5 minutes to obtain an image-receiving sheet for thermal transfer recording. Was.

Comparative Example 6 An image receiving sheet for thermal transfer recording was obtained in the same manner as in Example 6 , except that the intermediate layer was not provided.

The two types of thermal transfer recording image-receiving sheets thus obtained were subjected to the same quality comparison test as described above.
Table 3 shows the results.

[0044]

[Table 3]

[0045]

As is evident from the results in the table, the image receiving sheet for thermal transfer recording obtained in the examples of the present invention has excellent recording sensitivity, not only can obtain a very clear recorded image with high color density, but also In particular, the image receiving sheet for thermal transfer recording was excellent in image quality.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-291990 (JP, A) JP-A-4-229293 (JP, A) JP-A-4-279393 (JP, A) JP-A 64-64 69392 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (2)

(57) [Claims] An image receiving sheet for thermal transfer recording comprising an image receiving layer for receiving a transfer image from a color material transfer sheet on a support, wherein the support of the image receiving sheet is a plastic film (provided that the surface of the support is (It does not have a separable polyolefin layer), and an intermediate layer containing a polyvinyl alcohol-based resin having a hydrophobic group in an amount of 18 to 80 mol% based on the total monomer composition was provided between the support and the image receiving layer. An image receiving sheet for thermal transfer recording, comprising: 2. An image receiving sheet for thermal transfer recording comprising an image receiving layer for receiving a transfer image from a color material transfer sheet on a support, wherein the support of the image receiving sheet is paper, and the support, the image receiving layer and And a polyvinyl alcohol-based resin having a hydrophobic group of 40 to 80 mol% in the total monomer composition and an organic resin.
An image receiving sheet for thermal transfer recording , comprising an intermediate layer containing powders .