JP6273965B2 - Method for producing thermal transfer image-receiving sheet - Google Patents

Description

  The present invention relates to a thermal transfer image receiving sheet used in a thermal transfer printer, and a thermal transfer image receiving sheet in which a heat insulating layer, an undercoat layer, and a dye receiving layer are sequentially laminated on one surface of a substrate, and the thermal transfer image receiving image The present invention relates to a sheet manufacturing method.

  In general, a thermal transfer recording medium is an ink ribbon called a thermal ribbon, which is used in a thermal transfer type printer. A thermal transfer layer is formed on one surface of a substrate, and a heat-resistant slipping layer is formed on the other surface of the substrate. (Back coat layer) is provided. Here, the thermal transfer layer is a layer of ink that is sublimated (sublimation transfer method) or melted (melt transfer method) by heat generated in the thermal head of the printer and transferred to the thermal transfer image receiving sheet side. is there.

  Currently, among the thermal transfer methods, the sublimation transfer method can easily form full-color images in accordance with the advanced functions of the printer, so it can be widely used for self-printing digital cameras, cards such as identification cards, and amusement output products. It's being used. Along with the diversification of such applications, there is a growing demand for miniaturization, high speed, low cost, and durability for the resulting prints. In recent years, the durability of prints has been increased on the same side of the base sheet. 2. Description of the Related Art Thermal transfer recording media having a plurality of thermal transfer layers provided so as not to overlap with a protective layer to be applied have become quite popular.

  Further, in order to reduce the environmental burden, there is a demand for a thermal transfer image receiving sheet in which the dye receiving layer and the undercoat layer are water-based. Under such circumstances, as the printing speed of printers increases with the diversification and widespread use of applications, the surface of the printed material becomes partially matte when black images are formed. However, it is particularly likely to occur in an aqueous thermal transfer image-receiving sheet.

  In order to solve such a problem, for example, in Patent Document 1, in the dye receiving layer, a crosslinked polyvinyl chloride having a crosslinked gel fraction of 20% or more, a K value of 40 or more, and an average degree of polymerization of 750 or more is used. It has been proposed to further include a mold release agent comprising an epoxy resin and an epoxy-modified silicone.

JP 2012-200902 A

However, using the thermal transfer image-receiving sheet proposed in Patent Document 1, the same high-speed printing printer is used in a high-temperature and high-humidity environment, and there are no countermeasures against kogation depending on the type of thermal transfer recording medium. It was confirmed that it was sufficient. In addition, the adhesiveness was insufficient, and a phenomenon trail occurred in which a part of the thermal transfer image receiving sheet was taken on the ink ribbon. Furthermore, image quality defects (non-uniformity) that are considered to be caused by hollow particles are also generated.
Up to now, various binders, additives, resin films, etc. have been reported for dye-receiving layers, undercoat layers, and heat insulation layers. However, when printing is performed in recent high-speed printing printers, Thus, no thermal transfer image-receiving sheet having good burnt, substrate adhesion and image quality has been found.

  The present inventors have found that the above problems can be achieved by defining materials used for the heat insulating layer, the undercoat layer, and the receiving layer, and have completed the present invention.

That is, the invention described in claim 1 is a method for producing a thermal transfer image-receiving sheet in which a heat insulating layer, an undercoat layer, and a dye-receiving layer are formed on one surface of a substrate, and a void is formed on one surface of the substrate. A step of forming a heat-insulating layer of the polyolefin film, and the upper surface of the heat-insulating layer includes both the polyolefin emulsion and the vinyl chloride copolymer emulsion having a glass transition temperature of Tg 40 ° C. or lower, and the polyolefin emulsion and Tg of 40 ° C. or lower. An undercoat layer is formed by applying and drying a coating solution for forming an undercoat layer containing a total solid content after drying of a certain vinyl chloride copolymer emulsion of 50% by mass or more based on the total solid content after drying. A coating solution for forming a dye-receiving layer containing a vinyl chloride copolymer emulsion having a glass transition temperature of Tg 60 ° C. or more and a film-forming aid on the upper surface of the step and the undercoat layer; The minimum film-forming temperature of G60 ° C. is at least vinyl chloride copolymer emulsion as 10 ° C. or less by coalescent, and a step of forming a dye-receiving layer by coating and drying.

The invention according to claim 2 is characterized in that the ratio of the PVC copolymer emulsion having a Tg of 40 ° C. or less to the polyolefin emulsion of the coating solution for forming the undercoat layer is in the range of 1/3 or more and 3 or less in terms of solid content. And a method for producing a thermal transfer image-receiving sheet.

A third aspect of the present invention is a method for producing a thermal transfer image-receiving sheet, characterized in that the vinyl chloride copolymer emulsion having a Tg of 40 ° C. or less of the coating solution for forming the undercoat layer does not contain an emulsifier.

The invention according to claim 4 is a method for producing a thermal transfer image-receiving sheet, characterized in that the vinyl chloride copolymer emulsion having a Tg of 60 ° C. or higher of the coating solution for forming a dye-receiving layer does not contain an emulsifier.

  According to the present invention, even if printing is performed on a thermal transfer image receiving sheet with a recent high-speed printing printer, a printed matter relating to a black high density portion when a black image is formed when printing is performed in a high temperature and high humidity environment. The image quality defect that the surface is partially matted does not occur, and the effect of good adhesion is exhibited.

It is a sectional side view of the thermal transfer image receiving sheet which concerns on embodiment based on this invention.

  Hereinafter, the present invention will be described in more detail. FIG. 1 is a schematic diagram of a thermal transfer image receiving sheet 1. The thermal transfer image receiving sheet 1 of the present invention comprises at least a substrate 2, a heat insulating layer 3, an undercoat layer 4, and a dye receiving layer 5.

  The base material 2 can be a conventionally known material, for example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polyethylene, films of synthetic resins such as polyvinyl chloride, polycarbonate, polyvinyl alcohol, polystyrene and polyamide. , And paper such as high-quality paper, medium-quality paper, coated paper, art paper, and resin-laminated paper can be used singly or in combination.

  The thickness of the substrate 2 can be in the range of 25 μm or more and 250 μm or less in consideration of the stiffness, strength, heat resistance, etc. of the printed material, but more preferably about 50 μm or more and 200 μm or less. .

  Next, the heat insulation layer 3 provided on one surface of the substrate 2 can be a conventionally known film as long as it is a polyolefin film containing voids. As the heat insulating layer 3, it is preferable to use a composite film in which a skin layer is provided on one side or both sides of a foamed film in consideration of, for example, smoothness or gloss that affects image quality. Further, by using a polyolefin film as the heat insulating layer 3, it is possible to prevent image quality defects (nonuniformity) peculiar to hollow particles.

  Although the thing of the range of 10 micrometers or more and 80 micrometers or less can be used for the thickness of the heat insulation layer 3, More preferably, the thing of about 20 micrometers or more and 60 micrometers or less is preferable.

The thermal transfer image receiving sheet 1 has at least an undercoat layer 4 between the heat insulating layer 3 and the dye receiving layer 5. Subbing layer 4 of the present invention, polyolefin down a glass transition temperature (hereinafter, referred to as Tg) By contains as a main component and vinyl chloride copolymer is 40 ° C. or less, the printing in recent high speed printing printers Even if it is performed, there is no image quality problem that the surface of the printed material is partially matted when a black image is formed in a high temperature and high humidity environment, and between the heat insulating layer 3 and the undercoat layer 4 and the undercoat layer. 4 and the dye receiving layer 5 can be made to have good adhesion.

Here, the main component of the above, as long as they do not impair the effects of the present invention, indicating that in addition to the vinyl chloride copolymer is less than the polyolefin emissions and Tg: 40 ° C., may be added further other components . Contained Specifically, as viewed from the entire undercoat layer 4 after the formation, but the sum of the vinyl chloride copolymer is less than polyolefin emissions and Tg: 40 ° C. are means that are included in more than 50 mass%, more than 80 wt% Preferably.

Further, polyolefin down the undercoat layer 4 has good affinity at the molecular level with a polyolefin film, which contributes to adhesion between the heat insulating layer 3 and the undercoat layer 4. Polyolefins down is preferably unchlorinated improve adhesion. On the other hand, vinyl chloride copolymer is less Tg: 40 ° C. contributes to adhesion between the undercoat layer 4 and the dye-receiving layer 5. Since the vinyl chloride copolymer is also contained in the dye receiving layer 5, it can be sufficiently adhered without causing cracks or voids at the interface between the undercoat layer 4 and the dye receiving layer 5.

  As the polyolefin emulsion and the vinyl chloride copolymer emulsion having a Tg of 40 ° C. or lower, known ones can be used and are not particularly limited. Examples of the vinyl chloride copolymer emulsion include vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic copolymer, vinyl chloride-acrylic-ethylene copolymer and the like.

  The vinyl chloride copolymer emulsion having a Tg of 40 ° C. or less may not contain an emulsifier, and the water resistance is improved by the absence of the emulsifier.

Subbing layer 4, a coating solution containing a emulsion PVC copolymer is less emulsion and Tg: 40 ° C. of polyolefin comprising it and contained as a main component after formation is formed by applying and drying. The ratio of the polyolefin emulsion: vinyl chloride copolymer emulsion of the undercoat layer 4 is preferably 25:75 to 75:25. In other words, it is preferable to set the ratio of the vinyl chloride copolymer emulsion having a Tg of 40 ° C. or less to the polyolefin emulsion in the range of 1/3 or more and 3 or less in terms of solid content.

  The thickness of the undercoat layer 4 can be in the range of 0.1 μm or more and 3 μm or less, but more preferably about 0.2 μm or more and 1.0 μm or less. If the thickness is less than 0.1 μm, it is difficult to adjust the film thickness of the undercoat layer 4, and if the film thickness is less than 0.1 μm and variations occur, the print density varies. Moreover, there is anxiety that the adhesiveness with the heat insulating layer 3 and / or the dye receiving layer 5 has a problem. On the other hand, if it exceeds 1.0 μm, the print density during high-speed printing will be low. Therefore, it is preferable that it is 1.0 micrometer or less from a viewpoint of cost.

Next, the dye-receiving layer 5 which is provided on the outermost surface of the heat insulating layer 3 side of the substrate 2 contains a vinyl chloride copolymer is at least Tg: 60 ° C. or higher, 10 ° C. by a film forming aid minimum film forming temperature Must be:

  As the vinyl chloride copolymer emulsion having a Tg of 60 ° C. or higher, a known emulsion can be used and is not particularly limited. For example, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic copolymer, vinyl chloride-acrylic-ethylene copolymer and the like can be mentioned. By using a vinyl chloride copolymer emulsion having a Tg of 60 ° C. or higher, a high reflection density can be obtained. The emulsion may not contain an emulsifier, and the absence of an emulsifier improves water resistance.

  Although the mechanism of kogation is not clear, it is considered that the surface of the printed material at the portion where the moisture is vaporized is partially matted because the undercoat layer 4 and the dye receiving layer 5 absorb moisture and the moisture is vaporized randomly. It is done. Therefore, it is likely to occur in water-based image receiving paper having a relatively high hygroscopic property. Further, when the undercoat layer 4 and the dye receiving layer 5 are poorly wet or when the film forming temperature of the emulsion is high, the dye receiving layer 5 does not spread uniformly after drying and cracks are generated on the surface. As a result, the hygroscopicity of the undercoat layer 4 increases, and moisture vaporization and kogation tend to occur.

  Furthermore, in order to give the thermal transfer recording medium a dye barrier property, when an aqueous resin layer is contained, kogation is more likely to occur.

  Although the reason is not clear, the moisture of the undercoat layer 4 evaporates through the dye receiving layer 5, so that the koge is strongly influenced by the undercoat layer 4. In order to prevent kogation, it is necessary to reduce cracks on the surface of the dye receiving layer 5 and to prevent vaporization of moisture from the undercoat layer 4.

  For the undercoat layer 4 and the dye receiving layer 5, a vinyl chloride copolymer emulsion is used together, and by making the film forming temperature 10 ° C. or less, cracks are hardly generated on the surface of the dye receiving layer 5. Furthermore, since the PVC copolymer emulsion of the undercoat layer 4 has a low Tg and the minimum film-forming temperature is significantly lower than the boiling point of water, sudden water vaporization is prevented. It is presumed that this is because the moisture moves to the dye receiving layer 5 without vaporizing in the undercoat layer 4.

  Examples of the film-forming auxiliary used in the dye-receiving layer 5 include various high-boiling solvents such as tripropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, propylene glycol, dipropylene glycol, and tripropylene glycol. In addition, it is also possible to use highly volatile ones such as acetylene glycol and acetylene glycol. When these are used, almost no residual solvent is generated. These may be used alone or in combination of two or more.

  The dye receiving layer 5 may contain a release agent. As the release agent, for example, various oils and emulsions such as silicones, fluorines and phosphates, surfactants, various fillers such as metal oxides and silica, waxes, and the like can be used. These may be used alone or in combination of two or more. Among these, it is preferable to use a silicone emulsion.

  The thickness of the dye receiving layer 5 can be in the range of 0.1 μm or more and 10 μm or less, but more preferably about 0.2 μm or more and 8 μm or less. Moreover, you may contain a crosslinking agent, antioxidant, a fluorescent dye, and a well-known additive as needed.

  Moreover, you may provide the contact bonding layer for bonding the base material 2 and the heat insulation layer 3 to the thermal transfer image receiving sheet 1 of this invention. As materials used for the adhesive layer, conventionally known materials can be used, for example, polyolefin resins such as polyethylene, urethane resins, acrylic resins, polyester resins, epoxy resins, phenol resins, vinyl acetate resins, etc. Can be used. Among these, polyethylene, urethane resin, and acrylic resin are preferable.

  Moreover, you may provide a back surface layer in the opposite side to the side in which the heat insulation layer 3 of the base material 2 is provided in the thermal transfer image receiving sheet 1 of this invention. The back layer is provided in order to improve printer transportability, prevent blocking with the dye receiving layer 5, and prevent curling of the thermal transfer image receiving sheet 1 before and after printing. As the material used for the back layer, conventionally known materials can be used, for example, polyolefin resins such as polyethylene resins and polypropylene resins, acrylic resins, polycarbonate resins, polyvinyl alcohol resins, polyvinyl acetal resins, polyester resins, polystyrene resins. A binder resin such as resin or polyamide can be used. Moreover, you may contain well-known additives, such as a filler and an antistatic agent, as needed.

  Below, the material used for each Example and each comparative example of this invention is shown. In the text, “part” is based on mass unless otherwise specified. The present invention is not limited to the examples.

Example 1
A high-quality paper having a thickness of 140 μm was used as a substrate, and a polyethylene resin layer having a thickness of 30 μm was formed on one surface by a melt extrusion method. Moreover, the 40-micrometer-thick heat insulation layer which provided the skin layer on the single side | surface of a foaming polypropylene film was prepared.

  Next, a polyethylene resin layer is formed by melting and extruding a polyethylene resin between the surface of the substrate opposite to the side of the polyethylene resin layer and the surface of the heat insulation layer where the skin layer is not provided. And pasted together. The melt-extruded polyethylene resin layer was formed to have a thickness of 15 μm.

  On the skin layer side of the foamed polypropylene film, the undercoat layer coating solution-1 was applied and dried so that the thickness after drying was 0.5 μm, thereby forming an undercoat layer. Further, on the undercoat layer, the dye-receiving layer coating solution-1 was applied and dried so that the thickness after drying was 3 μm, whereby a dye-receiving layer was formed, and the thermal transfer image-receiving sheet of Example 1 was formed. Obtained. In addition, the minimum film forming temperature was measured based on JISK6828-2.

<Undercoat layer coating solution-1>
25.3 parts of polyolefin emulsion (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
14.7 parts of vinyl chloride copolymer emulsion (Viniblanc 278, manufactured by Nissin Chemical Industry Co., Ltd., Tg 33 ° C., solid content 43%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts <Dye-receiving layer coating solution-1>
40.0 parts of vinyl chloride copolymer emulsion (Viniblanc 603, manufactured by Nissin Chemical Industry Co., Ltd., Tg 63 ° C., solid content 50%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 55.0 parts Silicone emulsion 1.0 part (BY 22-736 EX, manufactured by Toray Dow Corning Co., Ltd.)
Film forming temperature 7 ℃

(Example 2)
A thermal transfer image-receiving sheet of Example 2 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating solution-2 of the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Undercoat layer coating solution-2>
Polyolefin emulsion 14.6 parts (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
25.4 parts of vinyl chloride copolymer emulsion (Viniblanc 278, manufactured by Nissin Chemical Industry Co., Ltd., Tg 33 ° C., solid content 43%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

(Example 3)
A thermal transfer image-receiving sheet of Example 3 was obtained in the same manner as in Example 1 except that the thermal transfer image-receiving sheet produced in Example 1 was changed to the undercoat layer coating solution-3 of the following composition.
<Undercoat layer coating solution-3>
Polyolefin emulsion 33.5 parts (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
6.5 parts of PVC copolymer emulsion (Viniblanc 278, manufactured by Nissin Chemical Industry Co., Ltd., Tg 33 ° C., solid content 43%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

Example 4
A thermal transfer image-receiving sheet of Example 4 was obtained in the same manner as in Example 1 except that the dye-receiving layer was changed to Dye-receiving layer coating solution-2 having the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution-2>
40.0 parts of vinyl chloride copolymer emulsion (Viniblanc 701, manufactured by Nissin Chemical Industry Co., Ltd., Tg 73 ° C., solid content 30%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 55.4 parts Silicone emulsion 0.6 parts (BY 22-736 EX, manufactured by Toray Dow Corning Co., Ltd.)
Film forming temperature 0 ℃

(Example 5)
A thermal transfer image-receiving sheet of Example 5 was obtained in the same manner as in Example 1 except that the thermal transfer image-receiving sheet produced in Example 1 was changed to the undercoat layer coating solution-4 of the following composition.
<Undercoat layer coating solution-4>
21.8 parts of polyolefin emulsion (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
18.2 parts of vinyl chloride copolymer emulsion (Viniblanc 711, manufactured by Nissin Chemical Industry Co., Ltd., Tg 30 ° C., solid content 30%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

(Comparative Example 1)
A thermal transfer image-receiving sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the thermal transfer image-receiving sheet produced in Example 1 was changed to the undercoat layer coating solution-5 of the following composition.
<Undercoat layer coating solution-5>
Polyolefin emulsion 40.0 parts (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

(Comparative Example 2)
A thermal transfer image-receiving sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that the thermal transfer image-receiving sheet produced in Example 1 was changed to the undercoat layer coating solution-6 of the following composition.
<Undercoat layer coating solution-6>
40.0 parts of a vinyl chloride copolymer emulsion (Vinibrand 278, manufactured by Nissin Chemical Industry Co., Ltd., Tg 33 ° C., solid content 43%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

(Comparative Example 3)
A thermal transfer image-receiving sheet of Comparative Example 3 was obtained in the same manner as in Example 1 except that the thermal transfer image-receiving sheet prepared in Example 1 was changed to the undercoat layer coating solution-7 of the following composition.
<Undercoat layer coating solution-7>
26.7 parts of polyolefin emulsion (Arrow Base SB-1010, manufactured by Unitika Ltd., solid content 25%)
13.3 parts of vinyl chloride copolymer emulsion (Viniblanc 603, manufactured by Nissin Chemical Industry Co., Ltd., Tg 63 ° C., solid content 50%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 56.0 parts

(Comparative Example 4)
A thermal transfer image-receiving sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that the dye-receiving layer was changed to Dye-receiving layer coating solution-3 having the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution-3>
40.0 parts of a vinyl chloride copolymer emulsion (Vinibrand 278, manufactured by Nissin Chemical Industry Co., Ltd., Tg 33 ° C., solid content 43%)
Tripropylene glycol monomethyl ether 4.0 parts Pure water 55.1 parts Silicone emulsion 0.9 part (BY 22-736 EX, manufactured by Toray Dow Corning Co., Ltd.)
Film forming temperature 0 ℃

(Comparative Example 5)
A thermal transfer image-receiving sheet of Comparative Example 5 was obtained in the same manner as in Example 1 except that the dye-receiving layer was changed to Dye-receiving layer coating solution-4 having the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution-4>
40.0 parts of vinyl chloride copolymer emulsion (Viniblanc 603, manufactured by Nissin Chemical Industry Co., Ltd., Tg 63 ° C., solid content 50%)
Pure water 59.0 parts Silicone emulsion 1.0 part (BY 22-736 EX, manufactured by Toray Dow Corning Co., Ltd.)
Film forming temperature 58 ℃

<Preparation of thermal transfer recording medium>
As a substrate, a polyethylene terephthalate film with a single-sided easy-adhesion treatment of 4.5 μm is used, and a heat-resistant slipping layer coating solution having the following composition is applied to the non-adhesive-adhesion-treated surface, and the coating amount after drying is 1.0 g / m ^2. It applied and dried so that it might become, and the base material with a heat-resistant slipping layer was obtained. Next, a primer layer and a thermal transfer layer coating solution having the following composition are applied to the surface of the substrate having a heat resistant slipping layer and dried so that the coating amount after drying is 1.0 g / m ^2. A thermal transfer layer was formed to obtain a thermal transfer recording medium.

<Heat resistant slipping layer coating solution>
Silicone acrylic graft polymer 50.0 parts (Toa Gosei Co., Ltd. US-350)
Methyl ethyl ketone 50.0 parts <Primer layer coating solution>
Polyvinyl alcohol 2.5 parts Isopropyl alcohol 30.0 parts Pure water 67.5 parts <Thermal transfer layer coating solution>
C. I. Solvent Blue 36 2.5 parts C.I. I. Solvent Blue 63 2.5 parts Polyvinyl acetal resin 5.0 parts Toluene 45.0 parts Methyl ethyl ketone 45.0 parts

<Print evaluation>
Using the thermal transfer image-receiving sheets and thermal transfer recording media of Examples 1 to 5 and Comparative Examples 1 to 5, a solid image was printed with a thermal printer for evaluation having a printing speed of 2.0 msec / line and a resolution of 300 × 300 DPI. The maximum reflection density was measured. The maximum reflection density is a value measured with X-rite 528.
Further, the thermal transfer image receiving paper sheet, the thermal transfer recording medium, and the thermal printer for evaluation were stored in an environment of 45 ° C. and 80% RH for 2 hours, and then a solid image was printed to evaluate kogation and adhesion. The evaluation results are shown in Table 1.

<Koge evaluation>
Evaluation of koge was performed according to the following criteria. Δ or more is a level where there is no practical problem.
A: No tendency to matte is observed in the shell of the thermal transfer medium.
○: Matting not recognized Δ: Matting slightly recognized ×: Matting recognized

<Adhesion evaluation>
The evaluation of adhesion was performed according to the following criteria, with the printed material peeled off with a cellophane tape. Δ or more is a level where there is no practical problem.
○: No interfacial peeling occurred Δ: Very slight peeling was observed between the heat insulating layer and the undercoat layer or between the undercoat layer and the dye image-receiving layer ×: Between the heat insulating layer and the undercoat layer Alternatively, peeling is observed between the undercoat layer and the dye image-receiving layer

  As can be seen from the results shown in Table 1, the undercoat layer contains a polyolefin emulsion and a PVC copolymer emulsion having a Tg of 40 ° C. or lower as main components, and the dye receiving layer contains a PVC copolymer emulsion having a Tg of 60 ° C. or higher. The thermal transfer image-receiving sheets of Examples 1 to 5 in which the minimum film-forming temperature of the vinyl chloride copolymer emulsion was set to 10 ° C. or less with a film-forming aid formed a black image when printed in a high-temperature and high-humidity environment. In the black high density portion, the surface of the printed material was partially matted and no poor image quality (cog) was generated, and the adhesion was good, and the effects of the present invention were confirmed.

In Example 2 in which the ratio of the polyolefin emulsion of the undercoat layer: vinyl chloride copolymer emulsion was 25:75, a decrease in the adhesion between the heat insulating layer and the undercoat layer was confirmed within a practically acceptable range. . In Example 3 in which the ratio of the polyolefin emulsion of the undercoat layer to the vinyl chloride copolymer emulsion was 75:25, it was confirmed that the adhesion force between the undercoat layer and the dye-receiving layer was lowered within a practical range. It was.
In Examples 4 and 5, when a vinyl chloride copolymer emulsion containing no emulsifier was used for the underlayer or the image receiving layer, no tendency to matte was observed in the ribbon shells.

On the other hand, the thermal transfer image-receiving sheet of Comparative Example 1 did not contain a polyolefin emulsion in the undercoat layer, so that the adhesion deteriorated, and peeling was observed between the heat insulating layer and the undercoat layer. The thermal transfer image-receiving sheet of Comparative Example 2 did not contain a vinyl chloride copolymer emulsion in the undercoat layer, so that the adhesion deteriorated and peeling was observed between the undercoat layer and the dye-receiving layer.
Further, when a vinyl chloride copolymer emulsion having a Tg of greater than 40 ° C. is used for the undercoat layer, the deterioration of the kogation is caused. Each was confirmed.

  The thermal transfer image-receiving sheet obtained by the present invention can be used in a sublimation transfer type printer, and in addition to the high speed and high functionality of the printer, various images can be easily formed in full color. It can be widely used for cards such as certificates and amusement output.

1: Thermal transfer image-receiving sheet 2: Base material 3: Heat insulation layer 4: Undercoat layer 5: Dye-receiving layer

Claims (4)

In the method for producing a thermal transfer image receiving sheet in which a heat insulating layer, an undercoat layer, and a dye receiving layer are formed on one surface of the substrate,
Forming the heat insulating layer of the polyolefin film including voids on one surface of the substrate;
After drying of the polyolefin emulsion and the PVC copolymer emulsion having a glass transition temperature of Tg 40 ° C. or lower on the upper surface of the heat insulating layer, and the polyolefin emulsion and the PVC copolymer emulsion having a Tg of 40 ° C. or lower A step of forming the undercoat layer by applying and drying a coating solution for forming an undercoat layer containing a total solid content of 50% by mass or more based on the total solid content after drying;
A coating solution for forming a dye-receiving layer containing a vinyl chloride copolymer emulsion having a glass transition temperature of Tg of 60 ° C. or higher and a film-forming aid is formed on the upper surface of the undercoat layer. And a step of forming the dye-receiving layer by applying and drying the emulsion at a minimum film-forming temperature of 10 ° C. or less with the film-forming auxiliary, and a method for producing a thermal transfer image-receiving sheet. The ratio of the PVC copolymer emulsion having a Tg of 40 ° C or less to the polyolefin emulsion of the coating solution for forming the undercoat layer is in the range of 1/3 or more and 3 or less in solid content ratio. 2. A method for producing a thermal transfer image receiving sheet according to 1. 3. The method for producing a thermal transfer image-receiving sheet according to claim 1, wherein the vinyl chloride copolymer emulsion having a Tg of 40 ° C. or less of the coating solution for forming the undercoat layer does not contain an emulsifier. The method for producing a thermal transfer image-receiving sheet according to any one of claims 1 to 3, wherein the vinyl chloride copolymer emulsion having a Tg of 60 ° C or higher of the coating solution for forming the dye-receiving layer does not contain an emulsifier.

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