JPH01198388A - Image receiving sheet for thermal transfer recording - Google Patents

Abstract

PURPOSE:To prevent the curling at the time of thermal transfer, by providing a resin layer containing a plate-shape inorg. substance on polypropylene synthetic paper having fine voids and further providing a dyeing resin layer thereon or on the opposite side. CONSTITUTION:An inorg. substance-containing resin layer 2 is provided on the single surface or both surfaces of synthetic paper 1. As the plate-like inorg. substance, a mica flake or talc having a wt. average aspect ratio (diameter/ thickness) of 10 or more is used. The plate-shape inorg. substance takes a structure horizontally overlapped with each other in a resin layer and suppresses curling at the time of heating. The content of the plate-shape inorg. substance in the resin layer is 5-80wt.% and the glass transition temp. of a resin may be 50 deg.C or more. In a dyeing resin layer 3, a resin having sufficient dyeability to a sublimable dye is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image-receiving sheet used in a recording method in which an image is obtained by thermal sublimation transfer from an electrical image signal.

[Conventional technology]

Among thermal transfer recording methods, the sublimation transfer method, which uses sublimable dyes, has excellent gradation and is most suitable for full-color printers that output color images from personal computers, televisions, vTRl video discs, etc. as still images. There is.

This image quality is greatly affected by the quality of the image-receiving sheet, and synthetic paper made from synthetic polymers provides better image quality than general paper made from cellulose, such as high-quality paper, art paper, and coated paper. . Among them, polypropylene synthetic paper obtained by stretching a polypropylene film containing inorganic fine powder and bonding it with many fine voids inside the film [e.g., product name: Yupo, egg oil synthetic paper] [Made by ■] has excellent water resistance and paper feeding/discharging properties, and due to the presence of voids, it has excellent cushioning properties and excellent contact with the head.
Gives good image quality.

However, in order to give this polypropylene-based synthetic #L77 feel and improve adhesion with the print head and paper feeding and ejection properties,
The film is stretched at a temperature lower than the melting point of the polyolefin material (for example, for homopolypropylene with a melting point of 164 to 166°C, the stretching temperature is 150 to 161°C) to form microvoids inside. ,
.

However, the heat resistance of polyolefin is lower than that of polyethylene terephthalate or polyamide (240 to 255°C), at 167°C or less, and when printing with a printing head, the temperature of the surface of the receiving sheet is higher than the stretching temperature. The temperature is close to 190 to 200 degrees Celsius, and the heat during printing causes the synthetic paper to shrink, and the heat-sensitive transfer receiving sheet is printed.
It has been pointed out that there is a curling problem on the printed inner side (
JP-A-60-245593, JP-A No. 61-283595).

[Problem to be solved by the invention]

Therefore, in the present invention, while taking advantage of the advantages of synthetic paper,
The purpose of this invention is to eliminate the above-mentioned curling disadvantage that occurs when synthetic paper is used as a base material for an image-receiving sheet.

[Means to solve the problem]

The present invention provides an image-receiving sheet for thermal transfer recording that is transferred by heating from a thermal transfer paper containing a sublimable dye. □ Advantages of synthetic paper by providing a plate-shaped resin layer containing an inorganic substance on at least one side of the paper, and providing a dyeing resin layer on the inorganic substance-containing resin layer side or the opposite side directly or through an intermediate layer. The object of the present invention is to provide a practically useful image-receiving sheet for sublimation heat-sensitive transfer recording, which prevents curling during heat transfer while taking advantage of the above properties.

(Structure of the Invention) The image-receiving sheet for thermal transfer recording of the present invention basically has a laminated structure shown in FIGS. 1 to 3. That is, as shown in FIG. 1, a three-layer structure consisting of a base synthetic paper (1), a plate-shaped inorganic substance-containing resin layer (2), and a dyeing resin layer on the opposite side; Or synthetic paper (as shown in Figure 2)
1), plate-shaped inorganic material-containing resin layer (2), and (2)
A three-layer structure with a dyed resin layer on top of the synthetic paper (1), or a plate-like inorganic material-containing resin layer (2) on both sides of synthetic paper (1), as shown in Figure 3. (A typical example is a four-layer structure in which two layers are provided and a dyeing resin layer (3) is provided on one side.)

Of course, in each of FIGS. 1 to 3, another resin layer,
An intermediate layer such as pulp paper may also be provided.

Polypropylene synthetic paper, which has many fine voids inside the film of synthetic paper (1), falls into the former category when divided into film method synthetic paper and fiber method synthetic paper, which are known synthetic paper manufacturing methods, and inorganic fine = 5- It is produced by extruding a composition whose main component is a polypropylene resin containing powder into a film through a slit in a die, and then cold-stretching or hot-stretching it.
Special Publication No. 46-40794, Japanese Patent Publication No. 60-245593
No. 61-112693). This synthetic paper is called an internal paper type, and voids are formed inside the film.

Examples of such polypropylene-based synthetic paper include product names YUPO FPG and KPKX TP.
GXDF (commercially available as j, etc.)

The thickness of the synthetic paper used as the base material is 40 to 30 microns, preferably 100 to 200 microns.

As the inorganic material-containing resin layer (2), a resin containing and dispersing a plate-shaped inorganic material is used. As the plate-shaped inorganic substance, mica flakes or talc having a weight average aspect ratio (diameter/thickness) of 10 or more are used. These plate-shaped inorganic substances are embedded in the inorganic substance-containing resin layer and have a horizontally overlapping structure, which is thought to be able to suppress the curling force of polypropylene synthetic paper when heated. . Therefore, a spherical inorganic material such as heavy calcium carbonate cannot provide a sufficient curl prevention effect. The particle size of this plate-shaped inorganic material is finer than 80 mesh sieve passes, preferably finer than 150 mesh sieve passes. Further, the content of the plate-shaped inorganic substance in the inorganic substance-containing resin layer is 5 to 80% by weight. If the content is less than 5% by weight, a sufficient anti-curling effect cannot be obtained, and if it exceeds 80% by weight, the adhesion between the synthetic paper and the inorganic material-containing resin layer will deteriorate.

As the resin containing this inorganic substance, any resin may be used as long as its glass transition temperature is 50°C or higher.
For example, acrylic polymers or copolymers of acrylic acid, methacrylic acid, acrylic acid alkyl esters, and methacrylic acid alkyl esters, thermoplastic resins such as polystyrene, saturated polyester resins, and polyvinyl chloride;
Alternatively, thermosetting resins such as phenol resins, epoxy resins, polyurethane resins, and unsaturated polyester resins are used.

The method for containing and dispersing plate-shaped inorganic substances in this resin is the usual paint manufacturing method in which the resin is used as it is in the case of liquid resin, or as a resin solution dissolved in an organic solvent or water, or as an emulsion. Use and disperse. For example, a plate-shaped inorganic substance is dispersed in part or all of the above-mentioned resin solution or emulsion using a known stirring device such as Daysilver or a dispersing device such as an attritor or a sand mill, and then the remaining resin is dispersed. ,
It can be manufactured by adding a solvent or the like to adjust the viscosity to a predetermined value. At this time, a coupling agent or the like may be used as appropriate to improve the dispersion of the inorganic substance in the resin.

This paint can be applied to synthetic paper by Myabar coating, air knife coating, reverse roll coating, etc. Next, by drying the organic solvent, water, etc., it can be applied in the form of a plate on synthetic paper. A resin layer containing an inorganic substance can be provided. Also,
The thickness of this inorganic substance-containing resin layer is 1 to 20% in terms of dry coating amount.
0t/rI? , preferably less than 5-b, there is no sufficient curl-preventing effect, and the upper limit is determined mainly by economic efficiency.

Next, as the dyeing resin layer (3), a wide variety of materials can be used as long as they have sufficient dyeability for sublimation dyes, such as thermoplastic polyester resin, epoxy resin, polyamide resin, acetic acid resin, etc. Examples include cellulose resin, polyvinyl butyral resin, and acrylic resin. These dyeing resin layers may contain release substances such as solid waxes, fluorine-based or phosphate ester-based surfactants, and silicone oils to prevent fusion with the thermal transfer paper. good. Further, if necessary, inorganic fine particles such as silica, calcium carbonate, titanium oxide, etc. may be contained, or the dyeing resin may be partially crosslinked.

The thickness of the dyed resin layer is usually 0.5 to 15 microns.

(Effect of the invention) A plate-shaped resin layer containing an inorganic substance is provided on at least one side of a polypropylene synthetic paper base material, and a plate-shaped resin layer containing an inorganic substance is provided on the side of the inorganic substance-containing resin layer or the opposite side thereof. By providing a dyed resin layer, it is possible to obtain an extremely practical image-receiving sheet for sublimation heat-sensitive transfer that does not curl after heat transfer.

(Examples, etc.) Below, resin production examples, examples, and comparative examples will be given and further explained in detail. The “part” mentioned in these examples is “
Parts by weight.

Resin production example 1 In a stainless steel pressure-resistant reactor equipped with a thermometer and a stirrer, Inprovil Alcohol 600? 200 f of methacrylate, 200 g of n-butyl methacrylate, and 2 t of azobisinobutyronitrile were charged into Methi, the inside of the system was purged with nitrogen gas, and the temperature was raised to 80° C. to initiate radical polymerization.

After 2 and 4 hours, azobisinobutyronitrile was added in an amount of 0.4 f each, and polymerization was carried out at 80° C. for a total of 6 hours to obtain an impure alcohol solution of resin (I). The glass transition temperature of this resin (I) was measured by DSC and was 57°C.

Resin production example 2 In a stainless steel pressure-resistant reaction vessel equipped with a thermometer and a stirrer,
Isopropyl alcohol 600 tons, methyl methacrylate 340 tons? , n-butyl methacrylate 60F, and 2 tons of azobisisobutyronitrile were charged, the inside of the system was replaced with nitrogen gas, and the temperature was raised to 80° C. to initiate radical polymerization.

After 2 hours and 4 hours, 0.4 f of azobisisobutyronitrile was added, and polymerization was carried out at 80° C. for a total of 6 hours to obtain an inpropyl alcohol solution of resin (n). When the glass transition temperature of this resin (If) was measured, it was found to be 8.
The temperature was 9°C.

Resin production example 3 Inopropyl alcohol 600 f, methacrylate 40 in a stainless steel pressure-resistant reactor equipped with a thermometer and a stirrer
? , 60 f of methyl methacrylate and 2 f of U azobisin butyronitrile were charged, the inside of the system was purged with nitrogen gas, and the temperature was raised to 80° C. to initiate radical polymerization.

0.4 t each of azobisin butyronitrile was added after 2 hours and 4 hours, and polymerization was carried out at 80° C. for a total of 6 hours to obtain an inopropyl alcohol solution of resin (1). The glass transition temperature of this resin (1) was measured and was 115.
It was ℃.

Resin Production Example 4 In a stainless steel pressure-resistant reaction vessel equipped with a thermometer and a stirrer, 600 f of ninoprobyl alcohol, 60 f of methyl methacrylate (x 340 f of n-butyl methacrylate), and 2 f of azobisinobutyronitrile were charged, and the system was purged with nitrogen. Gas was replaced and the temperature was raised to 80°C to start radical polymerization.

After 2 hours and 4 hours, 0.4 t of azobisisobutyronitrile was added, and polymerization was carried out at 80° C. for a total of 6 hours to obtain an inopropyl alcohol solution of resin (IV).

The glass transition temperature of this resin (I/') was measured to be 30°C.

Resin V Commercially available saturated polyester resin Vylon 200 (trade name,
Toyobo ■) was dissolved in methyl ethyl ketone, and 20
A weight t% resin solution (V) was prepared.

Examples 1 to 8, Comparative Examples 1 to 6 (Adjustment of coating liquid) The solutions of each resin ① to V obtained in each of the resin production examples above were diluted with methyl ether ketone, and the resin solid content concentration was 15% by weight. % of each resin solution.

An inorganic substance having the composition shown in Table 1 was added thereto, kneaded for 1 hour using an attritor, and then diluted with methyl ethyl ketone to obtain each coating solution having a solid content concentration of 10% by weight.

(Application of coating liquid onto synthetic paper base material) Each coating agent obtained by the above adjustment was applied to a thickness of 175 μm.
Examples 1 to 6, compared
The dry weight was about 91/rI on the back side for Comparative Examples 2 to 7, on the front side for Example 7, and on both sides for Example 8. It was coated with a bar coater so that it would be, and then dried with a hot air dryer at 80° C. for 1 hour to coat the paper.

-13= (Application of dyed resin layer) Next, using the synthetic paper on which the inorganic substance-containing layer was formed and the uncoated synthetic paper, saturated polyester resin (Vylon+2
00, trade name manufactured by Toyo Keisha Co., Ltd.) 20 parts, polyinocyanate compound (Coronate L1 trade name manufactured by Nippon Polyurethane Co., Ltd.)
For Examples 1 to 6 and Comparative Examples 2 to 7, a dyeing resin solution consisting of 3 parts and 77 parts of methyl ethyl ketone was applied to the opposite side of the inorganic substance-containing layer (comparative example 2 was the resin layer), and Example 7.8
For Comparative Example 1, the dry coating amount was 8 f / f on the surface of the synthetic paper described above.
It was coated with a bar coater so that the color was 100% fl”, dried in a hot air dryer at 90°C for 1 hour, and further dried at 50°C for 12 hours.
An image-receiving sheet for sublimation heat-sensitive transfer recording was prepared by aging for a period of time.

The following tests were conducted and evaluated using the sheets coated with only the inorganic substance-containing layer and the image receiving sheet coated with the dyed resin layer, before the dyed resin layer obtained in this way was coated, and the obtained results are shown in Table 1. Shown below.

=14- (Test method and evaluation method) (1) Adhesion between base material and inorganic material-containing layer A coated sheet is used only for the inorganic material-containing layer without coating the dyed resin layer. Use a cutter knife to draw 11 lines that reach the material at 1W+ intervals in each direction, and apply cellophane tape to the resulting 100 squares (denominator). First, the number of remaining squares (
molecule).

Evaluation criteria: 100/10G (0, excellent), 99/100~
90/100 (△, acceptable), 89/100 to 60/100
(X, poor), 59/100 to 0/100 (XX, extremely poor).

(2) Image quality of the transferred image Using an image receiving sheet coated with a dyed resin layer, an image of the same pattern is transferred to a Hitachi color video printer VY-50. Image quality was evaluated visually.

The evaluation criteria are: ○: Good condition, Δ: No practical problem, ×;
Slight uneven coloring, white spots, XX; Color unevenness, large white spots.

(3) After leaving the transferred image-receiving sheet used for image quality evaluation of the transferred image with a curl height of 2 in a constant temperature room at a temperature of 23°C and a humidity of 50% RH for 24 hours, the lifting height of the west end of the image-receiving sheet h( The average value of No. 4-) was expressed numerically (unit: ■).

(Margin below)

[Brief explanation of the drawing]

1, 2, and 3 are cross-sectional views of an image-receiving sheet according to the present invention, and FIG. 4 is an explanatory view for explaining a method for measuring curl height. In the figure, 1 is a synthetic paper base material, 2 is an inorganic-containing resin layer, and 3 is a dyed resin layer. In addition, A is the image receiving sheet after thermal transfer, B
is the horizontal plane (horizontal plate) and h is the curl height.

Claims (4)

[Claims] (1) In an image-receiving sheet for thermal transfer recording, which consists of a dyed resin layer and a base material, to which the dye is transferred by heating from a heat-sensitive transfer paper having a color material layer containing a sublimable dye, fine particles are formed inside the film as the base material. Using polypropylene synthetic paper with voids, providing a plate-shaped resin layer containing an inorganic substance on at least one side thereof, and directly or via an intermediate layer on the plate-shaped inorganic substance-containing resin layer side or the opposite side, An image-receiving sheet for thermal transfer recording, characterized by being provided with a dyed resin layer. (2) The plate-shaped inorganic substance is mica flakes or talc, and its weight average aspect ratio (diameter/thickness) is 10
The image-receiving sheet for thermal transfer recording according to claim 1, which is as described above. (3) The image-receiving sheet for thermal transfer recording according to claim 1, wherein the content of the plate-shaped inorganic substance in the inorganic substance-containing resin layer is 5 to 80% by weight. (4) The image-receiving sheet for thermal transfer recording according to claim 1, wherein the resin containing a plate-shaped inorganic substance has a glass transition temperature of 50° C. or higher.