JPH0585067A - Image receiving paper for thermal transfer recording - Google Patents

Abstract

PURPOSE:To provide image receiving paper for thermal transfer recording utilizing a heat-sublimable dye and prevented from becoming impossible to pass through a printer by the generation of a curl due to the relative humidity change of environment. CONSTITUTION:In image receiving paper for thermal transfer recording wherein an image receiving layer receiving a transfer image from a color transfer sheet is provided to the surface of a support composed of plain paper, an intermediate layer containing a binder with a glass transition point of 30-60 deg.C is provided between the support and the image receiving layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image-receiving paper for thermal transfer recording using a heat sublimation dye, and more particularly to a thermal transfer recording which prevents curling due to a change in relative humidity of the environment to prevent paper from passing through a printer. Regarding image-receiving paper.

[0002]

2. Description of the Related Art A thermal recording system which can obtain a recorded image at the same time as an input signal is used in various fields such as a facsimile, a computer terminal printer, and a measuring instrument printer because the apparatus is relatively simple and inexpensive and has low noise. Has been done. The recording paper used in these thermal recording systems is physically heated by heating,
A so-called recording layer provided with a recording layer that causes a chemical change to develop color,
The coloring type thermal recording paper is most commonly used.

However, the color-developing type thermosensitive recording paper is liable to cause unnecessary color development during the manufacturing process and storage, and the recorded image is inferior in storage stability, and is discolored by contact with an organic solvent or chemicals. There is a drawback that causes the phenomenon.

Therefore, a recording method using a colored coloring material itself has been proposed as a recording medium replacing the color-developing thermosensitive recording paper. For example, Japanese Patent Laid-Open No. 51-15446 discloses a solid or half-colored recording medium. Coloring material that is solid, paper,
It is coated on a support such as a polymer film, the color material on the support is brought into contact with the recording paper, and the color material on the support is heated by the thermal recording head to selectively select this color material. There has been proposed a method of obtaining a recorded image by transferring the image to a recording medium.

In this recording method, a coloring material on a support is melted, evaporated or sublimated by heat and transferred to a recording paper to obtain a recorded image by adhesion, adsorption or dyeing. There is a feature that paper can be used. In particular, in a recording method using a sublimable dye as a color material, an image excellent in gradation can be obtained, and therefore application to full color recording has been attempted.

However, when plain paper is used as the recording paper, dyeing is not particularly likely to occur, and not only the color density of the recorded image is low, but also a marked fading phenomenon occurs over time. Therefore, as described in JP-A-57-107885, U.S. Pat. No. 3,601,484 and the like, an image-receiving paper on which an image-receiving layer containing a thermoplastic resin as a main component is formed is used. Storability is improved.

Further, Japanese Patent Laid-Open No. 62-238791,
As disclosed in JP-A-61-277493 and the like, when the resin is crosslinked to improve the physical properties of the thermoplastic resin, or when printing is performed, the color material layer surface of the transfer sheet and the image receiving paper are used. In order to prevent the recording from being impossible due to fusion with the surface of the image receiving layer of JP-A No. 60-212374, a releasing material may be contained in the image-receiving layer or JP-A-62-62174. As disclosed in JP-A-222895, various proposals have been made for the purpose of improving printability and preventing fusion by using a resin modified with silicone or the like in the image receiving layer.

However, in the plain paper having the surface coated with the resin or the like, the equilibrium water content on the front surface and the back surface and the volume change amount due to the water content change are different. Usually, the resin on the front surface has a lower equilibrium water content than the cellulose fibers on the back surface, and the volume change amount due to the water content change is smaller. Therefore, a flat recording paper when the relative humidity of the atmosphere is relatively low generates curl with the surface inside when the relative humidity of the atmosphere is high, and conversely, a flat recording paper when the relative humidity of the atmosphere is relatively high. When the relative humidity of the atmosphere becomes low, curling occurs with the back surface inside. In other words, there is always a range of relative humidity in which such paper curls due to the difference in elongation between the front surface and the back surface and cannot pass through the printer. Such a recording paper cannot be put to practical use at all.

In order to improve such a defect, the equilibrium water content on the front surface and the back surface and the volume change amount due to the water content change may be made substantially the same. That is, the same resin as that on the front surface may be smeared on the back surface, which is exactly the same as the conventional coated paper for printing such as double-sided art paper. However, the resin that is smeared in order to improve recording suitability is an expensive resin such as polyester, and smearing it on the back surface only to prevent curling is a great economic disadvantage.

[0010]

In view of the present situation, the inventors of the present invention have found out the following as a result of earnest research on prevention of curling of the image-receiving paper for thermal transfer recording due to a change in relative humidity of the environment. The invention was completed.

[0011]

SUMMARY OF THE INVENTION The present invention provides an image-receiving paper for thermal transfer recording, which comprises an image-receiving layer for receiving a transfer image from a color material transfer sheet using a heat sublimable dye on the surface of a plain paper support. In the above, the image receiving paper for thermal transfer recording is characterized in that a coating layer containing a binder having a glass transition point of 30 to 60 ° C. is provided as an intermediate layer between the support and the image receiving layer.

[0012]

The image-receiving paper for thermal transfer recording of the present invention has a constitution in which an intermediate layer containing a binder having a glass transition point of 30 ° C. or higher and 60 ° C. or lower is provided on the surface of a support, so that the environmental humidity can be changed. It is possible to prevent the curl that accompanies it.

The intermediate layer of the present invention will be described in detail below.
To do. The intermediate layer has a glass transition point of 30 ° C or higher and 60 ° C or lower.
The coating material containing the binder
ー, air knife coater, bar coater, rod breaker
Do coater, roll coater, gravure coater, car
Using a ten coater, etc., the dry weight is 5 g / m ²
Above, desirably 8 to 25 g / m²Applying and drying
Form more.

The reason why the curl due to the change in the relative humidity of the environment can be prevented by providing this treatment layer is not necessarily clear, but it is presumed as follows. As described above, in order to prevent curling due to changes in the relative humidity of the environment, the equilibrium water content on the front and back surfaces and the volume change due to water content have been made almost the same so far, so that the front and back surfaces are Although it has been treated with a paint having the same constitution and properties, the intermediate layer of the present invention is completely different from this, and uses a binder having a considerably high glass transition point as compared with a binder for general paper coating. By bending,
That is, it is considered that it has high strength against curl.

It is generally desirable for the binder to have a low glass transition point in order to have a strong surface strength. For ordinary art paper, coated paper, etc., those having a temperature of 0 ° C. or lower are often used. According to experiments conducted by the present inventors, the glass transition point is 30 ° C.
If it is less than the above, the effect of the present invention cannot be obtained. It is considered that when the glass transition point is lower than 30 ° C., the binding strength to the pigment is sufficient, but the strength against bending is insufficient. On the contrary, even when the glass transition point exceeds 60 ° C., the effect of the present invention cannot be obtained. This is probably because when the glass transition point exceeds 60 ° C., the binding force to the pigment is insufficient and the strength of the intermediate layer is lost to the movement of the paper.

With such a binder, the surface strength is weak and it is difficult to obtain a good intermediate layer. Therefore, as a method of increasing the surface strength, a water-soluble binder is added and used in combination. However, if the water-soluble binder is added excessively, the water resistance is lowered and the desired performance cannot be exhibited. Therefore, the amount added is 15% of the total solid content of the intermediate layer.
The following is desirable. The water-soluble binder referred to here is, for example, starch, modified starch, protein-based adhesive,
Examples include polyacrylamide, various resins containing a carboxyl group and a hydroxyl group, such as carboxyl group-containing polyethylene, polyvinyl alcohol, and cellulose resins.

Examples of the pigment used in the intermediate layer of the present invention include inorganic pigments such as calcium carbonate, kaolin, titanium oxide, aluminum hydroxide and barium sulfate, urea resin fine particles, polystyrene resin fine particles and acrylic resin. Organic pigments such as fine particles and benzoguanamine-based resin fine particles are preferably used.

Further, the coating amount as a dry weight is 5 g / m.
If it is ² or less, it is insufficient to obtain the desired effect, 25 g /
When it is m ² or more, there is no significant change in the effect, and it is considered not desirable from an economic point of view. If necessary, antioxidants, dyes, defoamers, surfactants, antistatic agents, lubricants and other auxiliaries may be added to the intermediate layer. You may.

A backside treatment layer may be provided on the backside of the support. The back surface treatment layer uses a known blade coater, air knife coater, bar coater, rod blade coater, roll coater, gravure coater, curtain coater, etc., and has a dry weight of 5 g / m ² or more,
It is preferably formed by coating and drying at 8 to 25 g / m ² .

The reason why the more desirable effect can be obtained by providing the back surface treatment layer is considered to be that the effect of the intermediate layer is promoted by further providing the coating layer having high strength. The type and amount of the pigment and the water-soluble binder used in the back surface treatment layer do not necessarily have to be the same as those in the intermediate layer, but include a binder having a glass transition point of 30 ° C. or higher and 60 ° C. or lower similar to that of the intermediate layer. It is even more effective if you smear the paint. In addition, antioxidants, dyes, defoaming agents, surfactants, antistatic agents, lubricants, and other auxiliaries may be added to the back surface treatment layer as necessary for friction control, antistatic properties, writing properties, etc. Alternatively, it may be coated on the back surface treatment layer.

In the present invention, the image-receiving layer provided on the intermediate layer functions to receive the dye transferred from the color material transfer sheet, and so-called dyeing resins known in the art. The following synthetic resins are specifically exemplified. Polyester resin, polyacrylic ester resin, having an ester bond,
Polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin, etc. Polyurethane resin etc. as having urethane bond. Polyamide resin, etc. having an amide bond. Urea resin, etc. as having a urea bond.

The image-receiving layer is any one of these resins,
Alternatively, a combination of two or more types, known blade coater, air knife coater, bar coater, rod blade coater, roll coater, gravure coater,
Using a curtain coater, etc., the dry weight is 1 g /
It is formed by applying and drying m ² or more, preferably about ² to 10 g / m ² . In addition, if necessary, an antistatic agent, an ultraviolet absorber, an anti-fusing agent, an antioxidant, a dye, an antifoaming agent, a surfactant, a pigment such as colloidal silica, a cross-linking agent and other auxiliaries are added. Is also good.

Further, a barrier layer may be provided between the support and the image receiving layer. The barrier layer is usually an inorganic pigment, an aqueous solution of a water-soluble resin, an aqueous emulsion of a synthetic resin, an aqueous suspension, or a combination thereof, a known blade coater, air knife coater, bar coater, rod blade coater, roll. coater, gravure coater, using a curtain coater or the like, as dry weight, 3 g / m ² or more, preferably formed by coating and drying 8~30g / m ^2.

The advantages of providing a barrier layer are as follows. The image quality is improved by smoothing the surface of the support or imparting cushioning properties to enhance the adhesion between the thermal transfer recording color material transfer sheet and the image receiving paper. The image receiving layer is prevented from penetrating into the intermediate layer and not sufficiently covering the surface of the image receiving paper to improve the image quality. It suppresses the heat applied from the thermal head from escaping to the support and improves the thermal efficiency of the image receiving paper.

As the inorganic pigment, calcium carbonate, kaolin, titanium oxide, aluminum hydroxide, barium sulfate and the like are preferably used.

Examples of the water-soluble resin include polyacrylamide, various resins containing a carboxyl group and a hydroxyl group, for example, carboxyl group-containing polyethylene, polyvinyl alcohol, and cellulose resin.

As the synthetic resin constituting the aqueous emulsion and the aqueous suspension, polyacrylic acid ester,
Polymethacrylic acid ester, polyolefin, polybutadiene, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyurethane, polyester, etc., alkali soluble type, alkali swelling type, alkali non-swelling type, deformed polymer and co-polymer Can be used as a united body.

Further, if necessary, starch, modified starch, binder such as protein adhesive, antioxidant, dye, defoaming agent,
You may add surfactant and other auxiliary agents.

Next, the support will be described. Plain paper is used for the support. Plain paper here means art paper, coated paper, lightweight coated paper, lightly coated paper, coated paper such as cast coated paper, dull type, matte type coated paper, fine paper, medium quality paper, Non-coated paper such as super calendered paper and glossy base paper.

[0030]

EXAMPLES Examples will be described below to more specifically describe the present invention, but the present invention is not limited thereto. Further, “parts” and “%” in the text represent “parts by weight” and “% by weight”, respectively, converted into solid content unless otherwise specified.

Example 1 The following paint was prepared and smeared to form an intermediate layer. Kaolin [trade name: Ultra White-90, E.I. M. C. 90 parts, heavy calcium carbonate [trade name: BF-10]
0, Bihoku Powder Co., Ltd.] 10 parts were dispersed in water to give a solid content concentration of 50%. Furthermore, 20 parts of an acrylic emulsion having a glass transition point of 45 ° C. [trade name: Aron A-104, manufactured by Toagosei Co., Ltd.] was added to this as a binder,
Water was added to make the solid content concentration 35%. This is 101
dry weight on both sides of fine paper g / m ² to form an intermediate layer was plated dried with a wire bar so as to be 15 g / m ^2.

Next, a barrier layer paint was prepared as follows,
A smear was applied to provide a barrier layer. Modified styrene / butadiene / methylmethacrylate copolymer latex [trade name: JSR-0530, manufactured by Japan Synthetic Rubber Co., Ltd.] 90 parts of light calcium carbonate while stirring with a mixer [trade name: Brilliant S-15, Shiroishi Industry ( Co., Ltd.] was added and water was added to adjust the solid content concentration to 50%. Furthermore, 3 parts of oxidized starch, calcium stearate [trade name: Nopcoat C-104, manufactured by San Nopco Ltd.] 1
Parts were added and water was added to bring the solids concentration to 47%. This was applied on the intermediate layer with a wire bar so that the dry weight was 20 g / m ^2, and dried to form a barrier layer.

The following image-receiving layer paint was prepared and smeared on the surface of this barrier layer to form an image-receiving layer. 100 parts of polyester resin (trade name: Vylon200, manufactured by Toyobo Co., Ltd.),
Amino-modified silicone [Product name: KF-393, Shin-Etsu Chemical Co., Ltd.] 0.5 part, epoxy-modified silicone [Product name: X-22-343, Shin-Etsu Chemical Co., Ltd.]
0.5 part of methyl ethyl ketone / toluene (weight ratio 1:
It was added to 1) with stirring with a mixer and dissolved to obtain an image receiving layer coating liquid having a solid content of 15%. This was coated on the surface of the barrier layer with a wire bar so as to have a dry weight of 7 g / m ² and dried, and then subjected to a super calendar treatment to obtain an image-receiving paper for thermal transfer recording. Super calendar condition is linear pressure 90
kg / cm, chrome-plated metal roll surface temperature 70 ° C,
The sheet passing speed was 5 m / min, and the sheet passing number was 2 times.

The thermal transfer recording image-receiving paper thus obtained was subjected to a quality test as follows. That is, the image receiving paper for thermal transfer recording cut into 100 mm × 130 mm so that the paper-making direction is the longitudinal direction, the temperature is 40 ° C., and the relative humidity is 90%.
Under high-humidity atmosphere conditions, standard atmospheric conditions of temperature 20 ° C, relative humidity 65%, and low-humidity conditions of temperature 30 ° C, relative humidity 10% for one day, and measure the degree of curl.
The evaluation was performed and the results are shown in Table 1.

Example 2 As in Example 1, a high-quality paper provided with an intermediate layer was smeared with a barrier layer paint prepared as follows. 10 parts of titanium oxide [trade name: FA-55W, manufactured by Furukawa Mining Co., Ltd.] were dispersed with a Choles disperser, and a polyolefin resin pigment [Chemipearl A-100, manufactured by Mitsui Petrochemical Co., Ltd.] 3
0 parts, polystyrene resin pigment [Product name: Lowpaque OP
-84J, manufactured by Nippon Acrylic Co., Ltd.] 45 parts, polyvinyl alcohol [trade name: PVA-205, Kuraray Co., Ltd.]
5 parts, polystyrene / acrylic copolymer latex [trade name: Sebian A-4720, manufactured by Daicel Corp.]
10 parts was added to give a solid content concentration of 35%.

The dry weight of this was 15 g / m on high-quality paper.
^It was smeared and dried with a wire bar so as to have a thickness of 2, to form a barrier layer, and further subjected to a super calendar treatment. The super calender conditions were a linear pressure of 60 kg / cm, a chrome-plated metal roll surface temperature of 25 ° C., a paper feed speed of 5 m / min, and a paper feed frequency of 2 times.

On the surface of this barrier layer, the following image-receiving layer paint
Was prepared and smeared to provide an image receiving layer. Alcohol-modified silicone
Oil [Product name: Torre Silicone SF-842
7, Toray Silicone Co., Ltd.] 10 parts colloidal
Rica (trade name: Adelite AT-30A, Asahi Denka Co., Ltd.)
Made] 15 parts, aqueous modified urethane resin [Product name: Hydra
AP-40, manufactured by Dainippon Ink and Chemicals, Inc.] 100
Part, epoxy modified silicone oil [Product name: PORON
MF-11, Shin-Etsu Chemical Co., Ltd.] 3 parts, crosslinking catalyst [Product
Name: Catalyst PA-20, Dainippon Ink and Chemicals
Co., Ltd.] 2 parts were added to prepare an image receiving layer coating material. this
On the barrier layer surface with a dry weight of 7 g / m ²So that
It was smeared and dried with a wire bar. Others are the same as in Example 1.
Super calendar processing, evaluation, and display the results.
Shown in 1.

Example 3 An image receiving paper for thermal transfer was prepared in the same manner as in Example 2 except that the same paint as the intermediate layer paint in Example 2 was further provided as a back surface treatment layer, and the evaluation results are shown in Table 1. Indicated.

Example 4 An image receiving paper for thermal transfer recording was prepared by changing the intermediate layer and the back surface treatment layer in Example 3 as follows. Heavy calcium carbonate [Product name: Softon 1800, Bihoku Powder Co., Ltd.
Manufactured] 60 parts, light calcium carbonate [trade name: Brilliant S-15, manufactured by Shiraishi Industry Co., Ltd.] 40 parts, and sodium polyacrylate 0.2 parts dispersed in water by a Corres disperser to obtain a solid content concentration. 55% slurry with 3 parts oxidized starch,
20 parts of an acrylic emulsion (trade name: Aron A-104, manufactured by Toagosei Co., Ltd.) having a glass transition point of 45 ° C. was added, and a coating solution having a solid content concentration of 35% prepared by further adding water was added. Both surfaces of the high-quality paper were smeared and dried so that the amount of each side was 15 g / m ^{2. In} addition, a barrier layer smear, an image receiving layer smear, a super calender treatment, and evaluation were performed in the same manner as in Example 2, and the results are shown in Table 1. It was

Example 5 A binder for the intermediate layer and the backside treatment layer in Example 3 was changed to some latexes having a glass transition point of -5 ° C to 65 ° C to prepare an image-receiving paper for thermal transfer recording,
The evaluation results are shown in FIG.

Example 6 The image transfer paper for thermal transfer recording was prepared by changing the smear dry weight of the intermediate layer and the back surface treatment layer in Example 3 from 0 g / m ² to 30 g / m ² , and the evaluation results are shown in FIG. Shown in 2.

Example 7 An image receiving paper for thermal transfer recording was prepared by changing the compounding ratio of the pigment and the binder in the intermediate layer and the back surface treatment layer in Example 3 from 95: 5 to 0: 100, and the evaluation results are shown. It is shown in FIG.

Example 8 An image receiving paper for thermal transfer recording was prepared by changing the intermediate layer and the back surface treatment layer in Example 2 as follows. Kaolin [trade name: Ultra White-90, E.I. M. C. 90 parts, heavy calcium carbonate [trade name: BF-10]
0, Bihoku Powder Co., Ltd.] 10 parts were dispersed in water to give a solid content concentration of 50%. In addition to this, glass transition point, 45 ℃
Acrylic emulsion [Product name: Aron A-104,
Toagosei Co., Ltd.] 20 parts, oxidized starch 15 parts,
Water was added to make the solid content concentration 30%. This was dried on both sides of the same base paper as in Example 2 to a dry weight of 10 g / m 2.
^It was smeared and dried with a wire bar so as to be ^2, and an intermediate layer and a back surface treatment layer were formed. Other conditions were the same as in Example 3, and an image receiving paper for thermal transfer recording was prepared, and the evaluation results are shown in Table 1.

Comparative Example 1 An image receiving paper for thermal transfer recording was prepared in the same manner as in Example 1 except that the intermediate layer was not provided, and the evaluation results are shown in Table 1.

Comparative Example 2 An image receiving paper for thermal transfer recording was prepared in the same manner as in Example 2 except that the intermediate layer in Example 2 was not provided, and the evaluation results are shown in Table 1.

Comparative Example 3 An image receiving paper for thermal transfer recording was prepared by changing the intermediate layer and the back surface treatment layer in Example 2 as follows. Heavy calcium carbonate [Product name: Softon 1800, Bihoku Powder Co., Ltd.
Manufactured] 60 parts, light calcium carbonate [trade name: Brilliant S-15, manufactured by Shiraishi Industry Co., Ltd.] 40 parts, and sodium polyacrylate 0.2 parts dispersed in water by a Corres disperser to obtain a solid content concentration. 3 parts of oxidized starch and modified styrene-butadiene copolymer latex in 55% slurry (trade name:
JSR-0696, manufactured by Japan Synthetic Rubber Co., Ltd.] was added to 12 parts, and water was further added to prepare a coating solution having a solid content concentration of 50% so that the dry weight was 20 g / m ² per side. It was smeared on both sides and dried. Other than the above, barrier layer smearing, image receiving layer smearing, super calender treatment and evaluation were carried out in the same manner as in Example 2, and the results are shown in Table 1.

[0047]

[Table 1]

[0048]

As is clear from the results of the examples, the thermal transfer image-receiving paper of the present invention provided good results.

[Brief description of drawings]

1 illustrates the results of Example 5. FIG.

FIG. 2 illustrates the results of Example 6.

FIG. 3 illustrates the results of Example 7.

Claims (3)

[Claims] 1. A thermal transfer recording image-receiving paper comprising a plain paper support surface provided with an image-receiving layer for receiving a transfer image from a color material transfer sheet using a heat-sublimable dye, and having a glass transition point of 30 to 30. A coating layer containing a binder at 60 ° C.,
An image receiving paper for thermal transfer recording, which is provided as an intermediate layer between a support and an image receiving layer. 2. The image-receiving paper for thermal transfer recording according to claim 1, further comprising a coating layer containing a binder having a glass transition point of 30 to 60 ° C. as a back surface treatment layer. 3. The image-receiving paper for thermal transfer recording according to claim 1, wherein the intermediate layer and / or the back surface treatment layer contains a water-soluble binder in an amount of 15% by weight or less based on the total solid content of each layer.