JPH05318939A - Sublimation type thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To provide an inexpensive sublimation type thermal transfer image receiving sheet capable of obtaining a print image of high density and high image quality. CONSTITUTION:A sublimation type thermal transfer image receiving sheet is constituted by providing a plastic film layer on at least one surface of raw paper mainly composed of pulp and having a density of 0.2-0.5g/cm<3> and providing an image receiving layer on the plastic film layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sublimation type thermal transfer image receiving sheet (hereinafter simply referred to as a receiving sheet). More specifically, the present invention relates to a sublimation-type thermal transfer image-receiving sheet which, when used in a sublimation-type thermal transfer printer, can obtain a printed image with high density and excellent image quality.

[0002]

2. Description of the Related Art In recent years, development of a color hard copy of a thermal transfer system, in particular, a sublimation type thermal transfer printer has been rapidly advanced. In the sublimation thermal transfer printer, the sublimation dye layers of three colors (yellow, magenta, cyan) are heated by continuously controlling the heating energy of the thermal head to change the transfer amount of the dye of each color. It is possible to form a full-color image with density gradation.

Regarding the receiving sheet used in such a sublimation type thermal transfer printer, various proposals as described below have been made in order to obtain a print image with higher density and higher image quality. For example, in JP-A-62-59090,
It is disclosed that a plastic film having air bubbles inside is used as a support, whereby the smoothness is high and the heat insulation is high, so that a high-quality printed image can be obtained. However, when such a film alone is used as a support, there is a problem that the cost becomes high and that curling easily occurs due to heat at the time of printing, and it is difficult to put the film into practical use.

Further, JP-A-63-87286 discloses that a resin layer having fine pores is provided as a heat insulating layer on a support. In this case, although microballoons are used as the heat insulating layer, in such a structure, the thickness of the heat insulating layer must be made considerably large in order to obtain the desired heat insulating property, which increases the cost, and
Since the strength of the heat insulating layer becomes weak, there is a problem in practicality as an image receiving sheet.

Therefore, it has been desired to realize an inexpensive image receiving sheet which is excellent in heat insulating property and surface smoothness, can obtain a high density and high quality print image.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to provide an inexpensive sublimation type thermal transfer image receiving sheet which is excellent in heat insulating property and surface smoothness, can obtain a high density and high quality punto image. is there.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted earnest studies to obtain an image receiving sheet which has solved the above-mentioned problems, and as a result, provided a plastic film layer on at least one surface of a base paper having a specific density. The present invention has been completed by finding that a printed image of high density and high image quality can be obtained by using an image receiving sheet having a constitution in which an image receiving layer is provided on a plastic film layer using the above sheet-shaped support.

That is, the sublimation type thermal transfer image-receiving sheet of the present invention comprises a sheet-like support and an image-receiving layer formed on at least one surface of the sheet-like support and made of a dye-receptive resin material. And the sheet-like support contains pulp as a main component, and has 0.2 to 0.5 g / cm 2.
^It is characterized by comprising a base paper having a density of ³ and a plastic film layer formed on the surface of the base paper on which the image receiving layer is formed.

[0009]

The base paper used in the present invention is 0.2 to 0.5 g.
It has a density of / cm ³ . Such base paper is
The volume of the fiber component is made up of pulp and is 1 by heating.
It is obtained by mixing paper with so-called expandable particles, which is composed of capsules containing as a core substance a liquid that increases from 0 to 100 times, and expanding the capsules by heating.

Since the base paper obtained as described above has excellent heat insulating properties and cushioning properties, a high density print image can be easily formed on the image receiving layer formed thereon. However, since the surface of such a base paper has low smoothness, the flatness of the printed surface becomes poor, and it is difficult to obtain strong gloss like a photograph. Therefore, in the present invention, it is necessary to provide a plastic film layer on the surface of the raw paper on which the image receiving layer is provided. The sheet-like support thus obtained is an epoch-making one that enables formation of a high-density and high-quality printed image as compared with the conventional receiving sheet base material.

The materials used in the present invention will be described in detail below. The pulp for producing the base paper used in the present invention is not particularly limited, for example, wood pulp obtained by subjecting softwood and hardwood to chemical treatment and mechanical treatment, waste paper pulp, hemp and cotton, etc. Non-wood pulp, synthetic pulp made from polyethylene, polypropylene or the like can be used. These pulps may be used alone or in combination of several kinds.

Furthermore, in addition to the above pulp, acrylic fiber, rayon fiber, phenol fiber, polyamide fiber,
Various fibers such as organic fibers such as polyester fibers, inorganic fibers such as glass fibers, carbon fibers and alumina fibers may be mixed and mixed, but from the viewpoint of paper-making properties, it is preferable to add pulp in an amount of 50% by weight or more.

The expandable particles used for producing the base paper used in the present invention have a diameter of 4 to 5 times and a volume of 1 by being heated at a heating temperature of 80 to 200 ° C. for a short time.
It is a microcapsule that expands 0 to 100 times, and its original average particle size is 10 to 30 μm. Such a microcapsule contains a volatile organic solvent such as isobutane, pentane, a low boiling point halogenated hydrocarbon, and methylsilane, and is prepared from at least two copolymers such as vinylidene chloride, acrylonitrile, acrylic acid ester, and methacrylic acid ester. It is wrapped with a thermoplastic resin. That is, when the thermoplastic resin forming the shell of the microcapsule is heated above its softening point, the thermoplastic resin shell begins to soften, and at the same time the vapor pressure of the volatile organic solvent contained increases. Then, the microcapsules expand and form closed cells. Therefore, the base paper produced by mixing pulp and expandable particles and foaming them becomes a base material having a low density and excellent heat insulating properties.

The density of the base paper used in the present invention is 0.2 to 0.5 g / cm ³ . This density is 0.2
When it is less than g / cm ³ , the strength of the base paper becomes insufficient, and when it exceeds 0.5 g / cm ³ , the heat insulation becomes insufficient when it is used as a substrate.

In order to obtain a base paper having a density of 0.2 to 0.5 g / cm ^3, the amount of expandable particles added is 10
The amount is preferably 1 to 40 parts by weight, more preferably 3 to 20 parts by weight, based on 0 parts by weight. The heating temperature for foaming is preferably in the range of 110 to 140 ° C.
If the amount of the expandable particles to be blended is less than 1 part by weight, sufficient closed cells may not be obtained and the base paper density may become excessively high. Further, if it exceeds 40 parts by weight, uniform bubbles cannot be obtained, and the strength of the base paper may be excessively lowered. Further, if the heating temperature is lower than 110 ° C, sufficient foaming cannot be obtained, and if the heating temperature is higher than 140 ° C, the microcapsule film may be melted and closed cells may not be obtained.

In the step of mixing pulp and expandable particles, various retention aids, paper strength enhancers, sizing agents, fillers and the like may be appropriately selected and added, and further dyes, pH adjusters,
You may add a slime control agent, a defoaming agent, etc. as needed. Further, starch, polyvinyl alcohol, surface sizing agents, pigments, etc. may be applied to the surface of the raw paper with a size press, gate roll, blade coater, air knife coater or the like.

Using the above-mentioned constituents as main raw materials, a base paper is made into paper by an ordinary paper machine. First, a sheet-like body is formed from pulp slurry through a wire part in a papermaking process, and then dehydrated by a press part. Next, it is dried in the dryer part, but the temperature of the surface of the multi-cylinder type or Yankee type dryer of this dryer part causes the expandable particles mixed in the base paper to foam at the same time as the drying, resulting in a large number of closed cells in the base paper. To form a base paper having a low density and excellent heat insulation.

The basis weight of the base paper used in the present invention is 10 to 10.
It is preferably 0 g / m ² , more preferably 30
Is about 70 g / m ² . When the basis weight is less than 10 g / m ² , a base paper having sufficient heat insulation cannot be obtained, and 100 g / m
^If it exceeds ² , the load on the dryer of the paper machine increases and the economy may deteriorate.

Next, a plastic film layer is formed on one surface or both surfaces of the base paper to form a sheet-like support. As the plastic film used in the present invention, a film made of polyolefin, polyester, polyurethane, polycarbonate, polystyrene, vinyl chloride resin, acrylic resin, cellulose resin or the like is used.

Among these, polyolefin films include polyethylene, polypropylene, films made of their copolymers, polyolefin synthetic papers, films made of ethylene-acrylic acid copolymers and ethylene-vinyl acetate copolymers. It is illustrated. These films include white fillers such as titanium dioxide and alumina,
If necessary, a plasticizer such as phthalic acid ester, an antistatic agent, a release agent, etc. can be added. The thickness of the plastic film layer is preferably from 5 μm to 120 μm.

The above-mentioned plastic film can be produced by a known method such as an extrusion method, a calender method, a casting method or an inflation method. In the present invention, as a method of laminating the base paper and the plastic film, there are a method of laminating the base paper and the plastic film using an adhesive, a method of extrusion coating the base paper with plastic, and the like. It is also possible to laminate another plastic film while extruding a certain plastic as an adhesive.

The image-receiving sheet of the present invention is prepared by providing an image-receiving layer on the surface of the plastic film layer of the sheet-shaped support. The resin used in the image receiving layer of the present invention is required to have good dyeing property of dye, high transfer speed, high image density, little discoloration due to heat, and good running property. Specifically, the image receiving layer is formed of a polyester resin, a polycarbonate resin, a vinyl chloride copolymer, an active energy ray curable resin, or the like.

In the image receiving layer, a resin crosslinking agent, a lubricant, a release agent, a pigment or the like is usually added as necessary in order to prevent fusion with the ink sheet due to heat during printing. is there. Further, other additives such as pigments, fluorescent dyes, dyes such as blue and violet, ultraviolet absorbers and antioxidants may be added, if necessary. These additives may be mixed with the main component of the image receiving layer, or may be provided as a separate coating layer above or below the image receiving layer.

The thickness of the image receiving layer is preferably 1 to 10 μm, more preferably 2 to 6 μm.
When the thickness of the image receiving layer is less than 1 μm, defects such as a decrease in image density and sensitivity or a decrease in gloss on the printed surface may occur. If it is thicker than 10 μm, the effect is saturated, which is uneconomical and the strength of the image-receiving layer may be excessively lowered.

A layer containing an antistatic agent is provided on at least one surface of the image receiving sheet in order to prevent static electricity from being generated during running of the image receiving sheet in the printer and troubles in running. Good. As the antistatic agent, a cationic hydrophilic polymer material is advantageously used.

[0026]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention. In addition, all "%" and "parts" in an Example show "weight%" and "weight part."

Example 1 A slurry of mixed pulp consisting of 80% hardwood bleached kraft pulp beaten to a Canadian standard freeness of 450 ml and 20% softwood bleached kraft pulp beaten to a Canadian standard freeness of 470 ml was mixed into a slurry of pulp. 5 parts of expandable particles having an average particle size of 10 to 20 μm (Matsumoto Yushi-Seiyaku Co., Ltd., trademark: Matsumoto Microsphere F-30D, maximum foaming temperature 130 ° C.) per 100 parts of dry pulp, dry paper strength enhancer (manufactured by Arakawa Chemical Co., Ltd. Trademark: Polystron 117) 0.2 part, cationized starch (Oji National, trademark: CATO-15) 1.0
Part, alkyl ketene dimer type sizing agent (manufactured by Arakawa Chemical,
After adding 0.03 part of the trademark: Size Pine K903) and 0.4 part of a wet paper strength enhancer (trade name: Kamen 557H, manufactured by Dick Hercules Co., Ltd.) while stirring well,
The pulp concentration was adjusted to 0.03% and the PH was adjusted to 7.3 to prepare a papermaking raw material.

Using the obtained papermaking raw material, papermaking is carried out by a cylinder paper machine, heat-dried by a Yankee dryer at 130 ° C. to foam the expandable particles, and then dried by a continuous multi-cylinder dryer. Machine calendered at a linear pressure of 30 kg / cm, basis weight 60 g / m ² , thickness 120 μm, density 0.5
A base paper of g / cm ³ was prepared.

On both sides of the base paper obtained above, a thickness of 50 μm
m polyester film (Toray, trademark: Lumirror)
Are laminated by a dry lamination method using a polyester adhesive to form a sheet-like support, and then, on one surface of the sheet-like support, an image-receiving layer-forming coating composition having the following composition is added in solid content. An image receiving layer was formed by coating by a die coating method and drying so as to have an image receiving layer of 6 g / m ² . Paint for forming image receiving layer Weight part Saturated polyester resin 100 (Toyobo, trademark: Byron 200) Silicone resin 5 (Toray Dow Corning Silicone, trademark: SH3746) Toluene / methyl ethyl ketone = 4/1 mixed solvent 595

Example 2 An image receiving paper was prepared in the same manner as in Example 1. However, the amount of the expandable particles added was 10 parts (vs. dry pulp). The obtained sheet-shaped support has a basis weight of 30 g / m ² and a thickness of 12
It had a thickness of 0 μm and a density of 0.25 g / cm ³ .

Comparative Example 1 An image receiving paper was prepared in the same manner as in Example 1. However, the amount of expandable particles added was 2 parts (vs. pulp). The obtained sheet-shaped support has a basis weight of 72 g / m ² and a thickness of 120 μm.
m and the density was 0.6 g / cm ³ .

Comparative Example 2 An image receiving paper was prepared in the same manner as in Example 1. However, as a sheet-shaped support, the basis weight is 90 g / m ² , and the thickness is 120 μm.
m, density 0.75 g / cm ³ was used.

Performance Test Each of the image receiving papers obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was subjected to a sublimation video printer (VY-P1,
Printing was performed using Hitachi, Ltd., and the density and image quality of the obtained print image were evaluated. The results are shown in Table 1.

The density and image quality of the printed image were evaluated as follows. 1. Print density: The maximum density of the printed image was measured with a Macbeth densitometer (RD-914, manufactured by Kollmorgen Corp.). 2. Print image quality: Sensory evaluation of the image quality of the print image based on a sheet using a laminated base material of synthetic paper / coated paper / synthetic paper, with 3 being good, 2 being general and 2 being inferior It was displayed in three stages, with one as 1.

[0035]

[Table 1]

[0036]

According to the present invention, it becomes possible to prepare a sublimation type thermal transfer image receiving sheet which can obtain a printed image having a high print density and an excellent image quality, which greatly contributes to the industrial world.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tsunehisa Shigetani 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Product Research Laboratory

Claims (1)

[Claims] 1. A sheet-like support, and an image receiving layer formed on at least one surface of the sheet-like support and made of a dye-receiving resin material, wherein the sheet-like support is pulp. As the main component, and 0.2 to 0.5 g / cm
A sublimation type thermal transfer image receiving sheet comprising a base paper having a density of ³ and a plastic film layer formed on the surface of the base paper on which the image receiving layer is formed.