JP2770948B2 - Dye sublimation transfer recording sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dye sublimation transfer recording sheet that forms an image by thermally transferring a sublimation dye. More specifically, the present invention relates to a novel image recording sheet capable of thermally transferring a sublimation dye to form a clear and high-density image and having high strength and excellent image recording characteristics. It is.

[Conventional technology]

Recently, high-quality color copying technology using a thermal transfer recording system has been remarkably advanced and developed. Dye thermal transfer type printers can easily obtain high-quality recorded images, and have excellent characteristics such as high reliability of the device itself and relatively low value of the device. I have. In such a dye transfer system, the amount of dye transferred from the ink sheet can be continuously controlled by controlling the amount of heat applied from the thermal head. The dye sublimation temperature is Ts, and the dye layer peak temperature is
Assuming that Tp and the heating time are ts, there is the following equation between the image density D and Tp.

D = [ts (Tp−Ts)] ^1/2 + Dp (Dp represents the color density of paper) Therefore, three color (Y, M, C) or four color (Y, M, C, B) ink sheets From this, each dye is transferred by an amount determined by the heating time. That is, images of different hues are continuously formed according to the change in the amount of transfer of each dye, and the density gradation can be controlled.

In order to obtain a high-quality recorded image, it is required that the recording density of the dye to be transferred is high and the uniformity of the image is high. For this reason, a mixture of a pigment and a binder resin material is mainly used. There has been proposed a recording sheet in which an undercoat layer is provided below a sublimable dye-receiving layer.

For example, JP-A-61-248791 discloses that the average oil absorption is 35
A recording sheet is disclosed in which a coating layer containing a pigment having a particle size of 2 to 20 μm is formed on a support by coating.

[Problems to be solved by the invention]

The recording sheet used in the conventional sublimation transfer printer is a paper mainly composed of natural pulp, or a film mainly composed of a polyolefin resin, or a synthetic paper, etc., directly or through an undercoat layer. And the dye image receiving amount. However, although an image formed on a recording sheet using a polyolefin resin synthetic paper base has full color and high image quality, there is a disadvantage that the recording sheet is deformed by heating during recording. Further, a recording sheet using natural pulp paper has disadvantages such as lack of uniformity of image and low image density, and a satisfactory recording sheet has not been obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dye sublimation transfer recording sheet that can form a clear and high-density image with high uniformity, is relatively inexpensive, and has excellent practical recording suitability.

It is another object of the present invention to provide a sublimation transfer recording sheet which has good workability and excellent writability, has no deformation such as curl due to heat during recording, and has an excellent natural feeling.

[Means for solving the problem]

The present inventors have conducted various studies in order to solve the above-mentioned disadvantages of the prior art, and as a result, coated a silica, which is a kind of highly oil-absorbing inorganic pigment, on a support surface together with a binder resin material,
Furthermore, by adjusting the Bekk smoothness of the surface to 2,000 to 15,000 seconds to form an undercoat layer, it has been found that the image receptivity of a sublimation dye image receiving amount provided thereon can be remarkably improved. Thus, the present invention has been completed.

That is, the dye sublimation transfer recording sheet of the present invention is formed on at least one surface of a sheet-like support and this support,
And an undercoat layer containing, as a main component, a mixture of 30 to 80% by weight of silica and 20 to 70% by weight of a binder resin, and a surface smoothed to a Beck smoothness of 2000 to 15000 seconds; And a dye image receiving layer formed on the layer.

The recording sheet of the present invention has a high dye density transferred to the surface thereof, that is, a high image density, has good image uniformity, and therefore provides a high-quality image, and at the same time, has deformation such as curl due to heat during recording. In addition, it has good processability and can form an image recording with excellent natural feeling.

Silica used in the present invention is a rubber additive, a matting agent, a general hydrophilic silica that can be used for papermaking additives and the like,
Either a silane coupling agent or lipophilic silica surface-treated with paramfin may be used.
It may be a mixture of more than one species. Silica has a particle size of 1 to 10 μm
The fine particles are preferably In the undercoat layer main component mixture, the white pigment accounts for 30 to 80% by weight, preferably 40 to 80% by weight.
80% by weight. Silica content is 30% by weight
When it is lower, the image improving effect of the undercoat layer is insufficient, and when it is 80% by weight or more, the mechanical strength of the obtained undercoat layer is insufficient.

In the undercoat layer, as the pigment other than silica, white inorganic pigments and / or organic pigments used for general coated paper can be used. As such a white inorganic pigment, talc, light and heavy calcium carbonate, calcined kaolin, kaolin, zeolite, satin white and the like are used.
As the white organic pigment, those composed of a polymer substance having a glass transition point of room temperature or higher, such as urea-formalin resin, polystyrene, and polymethyl methacrylate, are used. The amount of the combined white pigment used is 30% based on the weight of silica.
The following is preferred. The combined white pigment may be mixed with the main component mixture, or a silica-binder resin material undercoat layer may be applied on the coating layer of the combined white pigment-binder resin material mixture. .

As a main component of the binder resin material used for the undercoat layer, in order to improve the adhesiveness to the pigment particles, a glass transition point is relatively soft SBR latex of 0 ° C. or less, acrylate copolymer, etc. It can be used alone or in combination with other adhesives.

Other binder resin materials may contain various water-soluble, solvent-soluble, or water-dispersible adhesives. Examples of such adhesive components include starch and polyvinyl alcohol. . The content of the binder resin material in the undercoat layer main component mixture is from 20 to 70% by weight, preferably from 35 to 70% by weight.
50% by weight. When the content exceeds 70% by weight, the effect of improving the image of the undercoat layer becomes insufficient, and the resolution of the image is reduced. When the content is lower than 20% by weight,
The strength of the obtained undercoat layer is insufficient and the mechanical strength is insufficient. The content of the main component consisting of the silica-binder resin material mixture in the undercoat layer is preferably at least 80% by weight.

Generally speaking, the undercoat layer preferably has a weight of 10 to 80 g / m ² , more preferably 10 to 40 g / m ² . When the undercoat layer is thin, the density and sensitivity of the obtained image are reduced, and the uniformity of the image is deteriorated. On the other hand, if the undercoat layer is too thick, the effect is saturated and not only is uneconomical, but also disadvantageously lowers the strength of the undercoat layer.

The undercoat layer of the present invention has a Beck smoothness of 2000 to 1500 by a surface smoothing means such as a super calendar.
The surface is smoothed to 0 seconds. By such a surface smoothing of the undercoat layer, a clear and high-density sublimation dye image can be received in the dye image receiving layer provided on the undercoat layer.

As the sheet-like support used in the recording sheet of the present invention, in addition to paper, synthetic paper and various plastic films can be used depending on the application, and in particular, the sizing degree is 10 seconds or more, and the smoothness is 30 seconds or more. Fine wood is preferable because it is inexpensive and has excellent heat resistance.

Although the thickness of the sheet-like support is not particularly limited, it is generally 10 to 200 μm, and the weighing is preferably 10 to ²⁰⁰ g / m ² .

Conventionally, dyes for dyeing polyester fibers used in the textile industry have been used as dyes for sublimation dye transfer printers. However, in the case of existing dyes, those having a low sublimation temperature have poor fixability and light resistance, while those having good fixation and light resistance have high sublimation temperatures and require large energy for transfer. was there. For this reason, special sublimation dyes are currently being developed for sublimation dye transfer.

As the image receiving layer for dyeing such a dye, a mixture of a resin base such as a polyester resin, a sensitizer, a release agent, a white pigment, or the like is used so that the sublimation dye is easily dyed. ing.

Generally the image-receiving layer of 1 to 30 g / m ² by weight, or 1~30μ
m.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples.
In the examples, "parts" indicates parts by weight of the solid content, the sheet before coating was used as a support, a sheet coated and coated with an undercoat layer was used as a recording sheet substrate, and a sublimation dye image was further formed thereon. The sheet coated with the receiving layer is referred to as a recording sheet.

Reference Example 1 Composition of undercoat paint-1 Pigment: silica (P78A, manufactured by Mizusawa Chemical) 100 parts Binder resin material: styrene butadiene copolymer (JSR0642, manufactured by Nippon Synthetic Rubber Co.) 50 parts Starch (Oji Ace B, Oji) Constarch) 10 parts Dispersant: sodium polyacrylate (Aron T40, manufactured by Toagosei Chemical Co., Ltd.) 1.5 parts A 40% by weight aqueous solution of the above component mixture was prepared as a reference undercoat paint, which was then weighed on a fine paper (weighing 64 g). / m ² ) was coated on one side of the support at a solid content of 30 g / m ² , dried, and smoothed with a super calender. A Beck smoothness of the undercoat layer surface was 1000 seconds, and a recording sheet base material having an opposite surface smoothness of 50 seconds was obtained. On the undercoat layer of this sheet substrate, polyester (Byron 20
0, manufactured by Toyobo Co., Ltd. in an amount of 10 g / m ² to form a sublimation dye image-receiving layer to obtain a recording sheet. The recording sheet was printed using a commercially available sublimation transfer printer (VY-50, manufactured by Hitachi, Ltd.), and the results of evaluating the quality are shown in Table 1.

However, evaluation items are color density, uniformity, color sharpness,
Thermal curl, strength of coating layer.

These sublimation transfer recording sheet results were evaluated on a five-point scale. (5 ... Excellent, 4 ... Good, 3 ... Normal, 2 ... Year poor,
1: poor) The color density was measured with a Macbeth densitometer.

The sharpness of coloring, the uniformity of the image, and the thermal curl after printing were evaluated by sensory evaluation, and the surface strength was evaluated by the degree of removal of the coating layer and the receiving layer by peeling the cellophane tape.

Example 1 Composition of undercoat paint-1 Pigment: Silica (P78A manufactured by Mizusawa Chemical Co., Ltd.) 80 parts Calcined clay (Ansilex Engelhard Company) 20 parts Binder resin material: Acrylic styrene copolymer (Movinyl 731 Hoechst Gosei Co., Ltd.) 50 Part: Polyvinyl alcohol (NL05, manufactured by Nippon Synthetic Chemical Company) 10 parts: Dispersant: sodium polyacrylate (Aron T40, manufactured by Toa Gosei Chemical Co., Ltd.) 1.5 parts: A coating material-1 having a concentration of 40% by weight was prepared from the mixture having the above composition. Was weighed onto a high-quality paper of 64 g / m ² at a solid content of 30 g / m ² , dried, and smoothed with a super calender. A Beck smoothness of the undercoat layer surface was 2000 seconds, and a recording sheet base material having an opposite surface smoothness of 50 seconds was obtained. On the undercoat layer of this substrate, polyester (Vylon 200, manufactured by Toyobo Co., Ltd.) was applied in an amount of 10 g / m ² to form a sublimation dye image-receiving layer, and a recording sheet was obtained. A commercially available sublimation transfer printer (VY-
Table 1 shows the results of printing using 50) and evaluating the quality.

However, the evaluation items are color density, uniformity, sharpness of white,
Thermal curl, strength of coating layer.

These sublimation transfer recording sheet results were evaluated on a five-point scale. (5 ... Excellent, 4 ... Good, 3 ... Normal, 2 ... Year poor,
1: poor) The color density was measured with a Macbeth densitometer.

The sharpness of coloring, the uniformity of the image, and the thermal curl after printing were evaluated by sensory evaluation, and the surface strength was evaluated by the degree of removal of the coating layer and the receiving layer by peeling the cellophane tape.

Example 2 Undercoat paint-2 composition Pigment: Surface-treated silica (P363, manufactured by Mizusawa Chemical Co., Ltd.) 100 parts Binder resin material: Acrylic ester copolymer (Paraloid B82 Rohm & Haas) 50 parts 20% by weight from the mixture of the above composition A toluene solution was prepared, and this was used as undercoat paint-2. This paint-2 was coated on one side of Yupo FPG80 (Oji Oil Chemical Synthetic Paper) forming a support at a solid content of 30 g / m ² , dried, and smoothed by a super calender. . A Beck smoothness of the undercoat layer surface was 15,000 seconds, and a recording sheet base material having an opposite surface smoothness of 500 seconds was obtained. The same treatment as in Example 1 was performed using this substrate. Table 1 shows the evaluation results of the printing quality of the obtained recording sheets.

Reference Example 2 Undercoat paint-4 composition Pigment: Kaolin (HG Clay Engelhard Co.) 100 parts Binder resin material: Styrene butadiene copolymer (JSR0642 Nippon Synthetic Rubber Co.) 50 parts Polyvinyl alcohol (NL05 Nippon Synthetic Chemical Company) 10 parts Dispersant: sodium polyacrylate (Alon T40, manufactured by Toa Gosei Chemical Co., Ltd.) 1 part On the same support as described in Reference Example 1, a coating layer of paint-4 was provided in an amount of 20 g / m ^2. after providing a further amount of the undercoat layer 20 g / m ² of reference undercoat paint thereon, this applies a smoothing process supercalendered, the smoothness of the coated surface
A recording sheet base material having a smoothness of 350 seconds and an opposite surface of 50 seconds was obtained. The same treatment as described in Reference Example 1 was performed using this substrate. Table 1 shows the evaluation results of the printing quality of the obtained recording sheets.

Comparative Example 1 The same processing as in Reference Example 1 was performed. However, the coating material-4 described in Reference Example 2 was applied to the support of Reference Example 1 to form a coating layer of 30 g / m ² , smoothing was performed with a super calender, and the Bekk smoothness of the coated surface was 4000 seconds. Thus, a recording sheet base material having a smoothness of the opposite surface of 50 seconds was obtained. The results are shown in Table 1.

Comparative Example 2 A synthetic paper Yupo FPG150 (thickness: 150 μm, Oji Oil Chemical Synthetic Paper) having a multilayer structure containing an inorganic pigment was used as a recording sheet base material, and a sublimation dye image receiving layer was formed thereon in the same manner as in Reference Example 1. Formed. The obtained receiving sheet was subjected to the same printing quality evaluation as in Reference Example 1. The results are shown in Table 1.

[Effect of the Invention] The sublimation transfer recording sheet of the present invention has a high image density, high color density, and high print quality by forming an undercoat layer containing silica under the dye image receiving layer. It shows excellent performance in that there is little thermal curl afterward, and the image freshness and natural feeling are all excellent. According to the present invention, a sublimation dye transfer print exhibiting a high resolution which has not been obtained in the past can be realized.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Toshikazu Nakura 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Product Research Institute (56) References JP-A-59-85792 (JP, A) 62-261486 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41M 5/38

Claims (1)

(57) [Claims] 1. A sheet-like support, and 30 to 80% by weight of silica formed on at least one side of the support,
An undercoat layer containing, as a main component, a mixture of 20 to 70% by weight of a binder resin material and having a surface smoothed to a Beck smoothness of 2000 to 15000 seconds, and a dye image receiving layer formed on the undercoat layer. A dye sublimation transfer recording sheet comprising: