JP2001138644A - Heat transfer image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new heat transfer image receiving sheet having the high heat insulating performance of an ink receiving layer and simultaneously an enough ink absorbency and enough ink anchoring effects and, in addition, a heat transferability excellent over the total range of the heat giving a thermal head ranging from a low energy (or a low density) to a high energy (or a high density), such as a low density transferability, a maximum density, a granular feeding, a dot reprodicibility, a surface layer strength, a gradation, a high glossy feeding or the like. SOLUTION: In the heat transfer image receiving sheet, in which the ink receiving layer is provided on a base material, a through hollow type plastic pigment having one or more through holes, through each of which the surface layer part of particles is connected with a gap within as a filler is included in the ink-receiving layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet suitable for a thermal transfer printer of a thermal fusion recording system, and has low density transferability, maximum density, granularity, dot reproducibility, surface layer strength,
The present invention relates to a thermal transfer image receiving sheet excellent in thermal transfer suitability such as gradation and high glossiness.

[0002]

2. Description of the Related Art In a thermal transfer printer of a thermal melting recording system, a thermal head is heated in accordance with an electric signal, and the amount of heat is transmitted to an ink ribbon to melt the heat-meltable ink. After transferring to the ink receiving layer and cooling and solidifying, the ink ribbon is separated from the ink receiving layer. Conventionally, inorganic fillers having high thermal conductivity, such as kaolin and calcium carbonate, have been used as the main component in the ink receiving layer, but the heat-melted ink comes into contact with the ink receiving layer due to poor heat insulating performance. Then, heat is dissipated and the viscosity of the ink increases, making it difficult for the ink to penetrate into the ink receiving layer. As a result, there are problems such as a decrease in density, poor transfer of low density, and low gloss.

In order to solve the above problem, it is necessary to enhance the heat insulating performance of the ink receiving layer.
An attempt to incorporate an organic filler (0.3 Kcal / m · hr · ° C.) having a low thermal conductivity into the ink receiving layer as disclosed in JP-A-63-21185, and JP-A-10-309875.
As disclosed in Japanese Patent Application Laid-Open No. H11-163, attempts have been made to incorporate a hollow organic filler into the ink-receiving layer, but all of them can improve the heat insulation performance or the cushioning property, but have the ink absorption and ink anchoring effects. Was insufficient, and sufficient thermal transfer suitability was not obtained.

[0004] On the other hand, as a method of improving the ink absorbency, etc. to enhance the fixing property of the ink and to prevent the ink from flowing,
A method of forming a porous layer on an ink receiving layer using a hydrophobic polyurethane as disclosed in JP-A-4-82790 or a method of forming a porous layer having a low miscibility with each other as disclosed in JP-A-5-87311. Attempts have been made to form a large number of pores on the surface by dissolving and coagulating more than one kind of resin, and the resulting porous layer and pores contribute to improving the heat insulation and cushioning properties of the ink receiving layer. However, there are problems such as difficulty in controlling the pore size, low gloss, and low surface layer strength.

[0005] In the disclosed example in which an organic filler having a low thermal conductivity or an organic filler having a hollow portion is added in order to enhance the heat insulating performance, the amount of the inorganic filler is reduced due to the addition of the organic filler, so that the ink absorbing property is reduced. In addition, it is considered that the anchoring effect of the ink became insufficient, and in the disclosed examples in which a porous layer was formed or pores were formed in the ink receiving layer, as a result, the heat insulating performance and cushioning property of the ink receiving layer However, it is considered that the gloss and the surface layer strength are reduced due to the formation of many pores on the surface.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems of the conventional thermal transfer image-receiving sheet, and has a high heat insulating performance of the ink receiving layer, and at the same time, has a sufficient ink absorbing property and ink anchoring effect. With a thermal transfer image receiving sheet,
Excellent thermal transfer aptitude in all areas where heat applied to the thermal head is from low energy (low density) to high energy (high density), ie, low density transferability, maximum density, granularity,
An object of the present invention is to provide a new thermal transfer image-receiving sheet having excellent thermal transfer suitability such as dot reproducibility, surface layer strength, gradation, and high glossiness.

[0007]

Means for Solving the Problems An object of the present invention, which has been made to solve the above problems, is to provide a thermal transfer image receiving sheet having an ink receiving layer provided on a base material, wherein particles as fillers are contained in the ink receiving layer. Characterized by containing a through-hollow-type plastic pigment having at least one through-hole connecting the surface layer portion to the internal space.

[0008] The above-mentioned hollow hollow plastic pigment can be suitably used as long as it has an oil absorption of 150% or more based on JISK5101. Further, the proportion of the hollow hollow plastic pigment present in the ink receiving layer is desirably 10 parts by weight or more based on 100 parts by weight of the solid content of the total filler in the ink receiving layer. Further, if the ratio F / R of the solid weight R of the binder resin to the solid weight F of all the fillers of the ink receiving layer is 1 to 5, the thermal transfer suitability can be further improved. In addition, the particle diameter of the penetrating hollow plastic pigment is preferably 0.5 μm or more.

According to the present invention, since the ink receiving layer contains a through-hollow plastic pigment having at least one through-hole connecting the surface of the particles to the internal space, the low-density transfer property, the highest density, A thermal transfer image-receiving sheet having excellent thermal transfer suitability such as graininess, dot reproducibility, surface layer strength, gradation, and high glossiness can be obtained. The sheet has excellent thermal transfer suitability because of the excellent thermal insulation and cushioning properties due to the hollow structure of the plastic pigment, and the excellent ink absorption property due to having fine pores in the penetrating structure. (Oil absorbency) and the effect of anchoring the ink. The fusion-type thermal transfer system is roughly classified into a wax-based penetrating type and a resin-based ink-on-ink type depending on the type of ink ribbon. The thermal transfer image-receiving sheet of the present invention is excellent not only in the ink-on-ink type but also in the penetrating type. Heat transfer suitability.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is an electron micrograph showing an example of a hollow hollow plastic pigment contained in the ink receiving layer of the thermal transfer image-receiving sheet of the present invention.

The thermal transfer image-receiving sheet of the present invention has a layer structure in which an ink receiving layer is provided on at least one surface of a substrate. As the substrate, any of paper, synthetic paper, plastic film and the like can be used. Synthetic paper provided with a paper-like layer having fine pores having relatively high smoothness and having pores inside and excellent heat insulation and cushioning properties, synthetic paper having a sea-island structure, or a porous film Is preferred.

As the paper, high quality paper, cast coated paper,
Art paper, coated paper, lightly coated paper, impregnated paper such as synthetic resin or emulsion, cellulose fiber paper and synthetic fiber pulp such as backing paper for wallpaper, non-cellulose fiber paper such as synthetic wood pulp, or cellulose fiber and non-cellulose fiber And the like.

As the synthetic paper, a synthetic paper provided with a paper-like layer containing fine pores (for example, YUPO), a synthetic paper having a sea-island structure (for example, peach coat) and the like can be used.

Examples of the plastic film include films using resins such as polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, methacrylate, and polycarbonate resins, and may be porous or non-porous. In particular, a porous film having excellent heat insulating properties and cushioning properties is preferable.

Next, the ink receiving layer provided on the base material is a layer for receiving the ink of the ink sheet, and is mainly composed of a binder resin (binder) and a filler (filler). The ink receiving layer is not limited to a single layer structure, and may have a multilayer structure of two or more layers. As the multilayer structure, a structure in which a release layer (anti-blocking) or an antistatic layer or the like is laminated on a layer containing a through-hollow plastic pigment, or an antistatic layer below a layer containing a through-hollow plastic pigment is provided. A laminated configuration and the like can be given.

The hollow hollow plastic pigment contained as a filler in the ink receiving layer is a multilayer emulsion particle having a void inside the particle and having a through hole from the particle surface to the internal void (small hole). (See FIG. 1). The whitish sphere in FIG. 1 is a hollow hollow plastic pigment, for example, the black part indicated by an arrow inside one of them (approximately 5 μm directly above the gauge shown in FIG. 1) is a through hole. It is. The material of the penetrating hollow plastic pigment is not limited, but acrylic, styrene or acryl-styrene copolymers are generally used.

The above-mentioned hollow hollow plastic pigment preferably has an oil absorption based on JIS K5101 of 150% or more. Even if the particle size is the same, the oil absorption differs depending on the porosity, the diameter and the number of through holes. Oil absorption 150%
If the amount is less than the above, the effects of anchoring and penetrating the ink become insufficient, and the thermal transfer suitability decreases. The method for measuring the degree of oil absorption conforms to the "linseed oil method" of JISK5101.

As the filler component contained in the ink receiving layer, the above-mentioned hollow hollow plastic pigment alone is most preferred, but other organic or inorganic fillers may be partially contained. Examples of the organic filler include fillers of non-penetrating type or hollow plastic pigment, cellulose-based, and urea-based fillers. Examples of the inorganic filler include silica, kaolin, calcium carbonate, talc, and titanium dioxide. However, if the content of the hollow hollow plastic pigment in the ink receiving layer is not less than 10 parts by weight based on 100 parts by weight of the total solid content of the filler in the ink receiving layer, sufficient thermal transfer suitability cannot be obtained.

The particle system of the above-mentioned hollow hollow plastic pigment is 0.1 μm to 5.0 μm, preferably 0.5 μm or more. When the particle diameter is less than 0.5 μm, the pore size (porosity) becomes small, the heat insulation performance and the cushion effect become insufficient, and the thermal transfer suitability of the ink receiving layer decreases. In addition,
The shape of the penetrating hollow plastic pigment particles does not matter, but is generally spherical.

The ink receiving layer contains at least a hollow plastic pigment as a filler and a binder resin, but may contain other filler components, anti-blocking components, antistatic components and the like as described above. .

Next, the ratio F / R of the solid content weight R of the binder resin in the ink receiving layer to the solid content weight F of all the fillers is 1
-5 is preferred. When the value of F / R is smaller than 1, the heat insulation and the effect of anchoring ink are reduced, and the thermal transfer aptitude is reduced. On the other hand, when the value of F / R is larger than 5, the surface layer strength is insufficient, and a part of the ink receiving layer is peeled off at the time of printing and transferred to an ink sheet, which is not preferable.

Regardless of the type of the binder resin, it can be appropriately selected in consideration of the compatibility with the ink sheet (ribbon) and the like. Types include acrylic, urethane,
Styrene, styrene-acrylic copolymers and the like can be mentioned.

The thermal transfer image-receiving sheet according to the embodiment of the present invention is as described above. The method for forming the ink-receiving layer on the base material includes a Meyer bar method, a reverse roll method, a gravure method, and a blade method. A known method such as an air knife method can be arbitrarily selected.

Further, an antistatic layer or a writing layer may be appropriately provided on the substrate on which the ink receiving layer is not provided.

[0025]

EXAMPLES Examples of the thermal transfer image-receiving sheet of the present invention will be described in detail below.

(Example 1) A polyethylene terephthalate film containing fine voids (Crisper G2323 100 µm, manufactured by Toyobo Co., Ltd.) was used as a substrate. As an ink receiving layer,
Urethane resin (made by Dainippon Ink and Chemicals, Hydran
100 parts by weight of AP-40, 22% solids), 330 parts by weight of a hollow hollow plastic pigment having a particle diameter of 1 μm (Grossdale 2001TX, manufactured by Mitsui Chemicals, 20% solids), and 10 parts by weight of water, and a sand grinder is added. The dispersion liquid was used as a coating liquid, and dried with a reverse roll coater on the above-described substrate to a thickness of 15%.
μm to obtain a thermal transfer image-receiving sheet of the first example of the present invention.

(Example 2) 50 parts by weight of a styrene alkyl acrylate copolymer resin (manufactured by BASF Dispersion, Acronal YJ27410D, solid content 56%), particle size 0.5
280 parts by weight of hollow plastic pigment of μm (Mitsui Chemicals, Grosdale 2000TX, solid content 20%), water 9
0 parts by weight, dispersed using a sand grinder, was used as a coating liquid.
The same base material as above was coated to a dry thickness of 15 μm to obtain a thermal transfer image-receiving sheet of the second example of the present invention.

(Example 3) 100 parts by weight of a urethane resin (manufactured by Dainippon Ink and Chemicals, Hydran AP-40, solid content: 22%), a hollow hollow plastic pigment having a particle diameter of 1 µm (Grossdale, manufactured by Mitsui Chemicals, Inc.) 2001TX, solid content 20%)
16.5 parts by weight, 29.7 parts by weight of silica (Mizukasil P707, manufactured by Mizusawa Chemical Co., Ltd.) having a particle size of 2.2 μm, and 130 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating liquid. The same substrate as in Example 1 was coated to a dry coating thickness of 15 μm to obtain a thermal transfer image-receiving sheet of the third example of the present invention.

(Example 4) 200 parts by weight of a urethane resin (manufactured by Dainippon Ink and Chemicals, Hydran AP-40, solid content: 22%), a hollow plastic pigment having a particle diameter of 1 μm (grossdale, manufactured by Mitsui Chemicals, Inc.) 2001TX, solid content 20%)
165 parts by weight, 33 parts by weight of silica (Mizukasil P707, manufactured by Mizusawa Chemical Co., Ltd.) having a particle size of 2.2 μm, and 150 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating liquid. Dry coating thickness 1 on the same substrate as 1
Coating was performed to a thickness of 5 μm to obtain a thermal transfer image-receiving sheet according to a fourth example of the present invention.

Example 5 120 parts by weight of a polyester resin (manufactured by Toyobo Co., Ltd., Vylonal MD100, solid content 30%), a hollow hollow plastic pigment having a particle diameter of 1 μm (manufactured by Mitsui Chemicals, Grosdale 2001TX, solid content 20%) ) 45 parts by weight,
Non-penetrating hollow plastic pigment with a particle diameter of 1 μm (Rohm & Haas, Rope Lake HP-91, solid content 28
%) 289 parts by weight and 176 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating solution. The same base material as in Example 1 was coated with a reverse roll coater to a dry coating thickness of 15 μm. A thermal transfer image-receiving sheet according to a fifth example of the invention was obtained.

Example 6 120 parts by weight of a polyester resin (manufactured by Toyobo, Vironal MD1100, solid content: 30%), a hollow hollow plastic pigment having a particle diameter of 1 μm (manufactured by Mitsui Chemicals, Grosdale 2001TX, solid content: 20%) ) 225 parts by weight, non-penetrating hollow plastic pigment with a particle diameter of 1 μm (manufactured by Rohm & Haas Co., Ltd., Ropaike HP-91, solid content 28)
%) 160 parts by weight and 125 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating liquid. The same base material as in Example 1 was coated with a reverse roll coater to a dry coating thickness of 15 μm. A heat transfer image-receiving sheet according to a sixth example of the invention was obtained.

(Comparative Example 1) Polyester resin (manufactured by Toyobo Co., Ltd., Vylonal MD1100, solid content 30%), 60 parts by weight, non-penetrating hollow plastic pigment having a particle diameter of 1 μm (manufactured by Rohm & Haas Co., Ltd., Ropeike HP-91, solid) Min 28%) 160
Parts by weight and 95 parts by weight of water were added, and a dispersion obtained by using a sand grinder was used as a coating liquid, and the same base material as in Example 1 was coated with a reverse roll coater to a dry coating thickness of 15 μm.
A thermal transfer image-receiving sheet of Comparative Example 1 was obtained.

(Comparative Example 2) 50 parts by weight of a styrene acrylic acid alkyl ester copolymer resin (manufactured by BASF Dispersion Co., Acronal YJ1555D, solid content 56%), particle diameter 1 μm
160 parts by weight of a filling-type plastic pigment (manufactured by Mitsui Chemicals, Inc., Grosdale 202-S, solid content: 35%) and 210 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating liquid. Was applied to the same substrate as in Example 1 to a dry thickness of 15 μm to obtain a thermal transfer image-receiving sheet of Comparative Example 2.

(Comparative Example 3) 100 parts by weight of a urethane resin (manufactured by Dainippon Ink and Chemicals, Hydran AP-40, solid content: 22%), silica having a particle size of 2.2 μm (Mizukasil, manufactured by Mizusawa Chemical Co., Ltd.)
P707) 33 parts by weight and 140 parts by weight of water were added, and the mixture was dispersed using a sand grinder to obtain a coating liquid. The same base material as in Example 1 was coated with a reverse roll coater to a dry coating thickness of 15 μm. A thermal transfer image-receiving sheet of Example 3 was obtained.

(Comparative Example 4) 100 parts by weight of a urethane resin (manufactured by Dainippon Ink and Chemicals, Hydran AP-40, solid content: 22%), silica having a particle size of 2.2 μm (Mizukasil, manufactured by Mizusawa Chemical Co., Ltd.)
P707) 22 parts by weight and 100 parts by weight of water were added, and the mixture dispersed using a sand grinder was used as a coating liquid. The same base material as in Example 1 was dried and coated with a reverse roll coater to a thickness of 15 μm.
To obtain a thermal transfer image-receiving sheet of Comparative Example 4.

The thus obtained thermal transfer image-receiving sheets of the first to sixth examples of the present invention and the thermal transfer image-receiving sheets of Comparative Examples 1 to 4 were
Thermal transfer color printer (Victor of Japan, Trueprint
2200: Originally a sublimation-type transfer printer, but modified so as to be able to form an image by the fusion transfer method), and use cyan, magenta, yellow, and black in order of level of heat energy in ascending order of level 1 ~ Level 10 of 10
Print a test pattern that prints a gray scale chart and cyan solid, and prints low density transferability, maximum density, granularity,
The printability was evaluated for the items of dot reproducibility, glossiness, and gradation, and the surface layer strength was evaluated by a cellophane tape peeling test.

The printability and the surface layer strength were evaluated in three stages (◎,
The evaluation was made by (○, ×), and a result of 以上 or more was regarded as a pass. (1) The low-density transferability was defined as ◎ when the reflection density of the black level 1 was measured with a Macbeth densitometer (RD-918), ○, 0.11 to 0.20 as 、, and 0.10 or less as x. (2) The maximum density is 1.40 or more of the value obtained by measuring the reflection density of cyan level 10 with a Macbeth densitometer (RD-918).
O to 1.39 was rated as O, and 0.99 or less was rated as x. (3) The graininess is determined by visually observing the solid portion of cyan, and there is no unevenness in printing or roughness of the image <, and those that are uniformly transferred are ◎, and slight unevenness in printing and roughness of the image are recognized,な い indicates that there is no practical problem, and X indicates that the print unevenness or roughness of the print is so severe that the image cannot be tolerated. (4) Dot reproducibility was measured using a digital microscope (Keyence Corporation, VH-630
Observed at 500 times using 0), ◎,
Some of the dots are missing or distorted, but those that have little effect on the image and pose no practical problems are evaluated as ○, and those with severely missing or distorted dots and poor dot transfer are identified as ×.
And (5) Regarding the glossiness, 45% or more of the value measured by a method according to JlSP8142 for the cyan solid portion was evaluated as ◎, 30 to 44% as ○, and 29% or less as ×. (6) In ten gradations of magenta from level 1 to level 10, the gradation density reaches the maximum density from level 7 to level 10, and the rise of the reflection density from level 1 to the maximum density is almost constant and gentle. When the gradient is ◎, the maximum density is reached from level 4 to level 6, but when the increase in the reflection density from level 1 to the maximum density is almost constant. A sample in which a key jump phenomenon was recognized was marked as x. (7) Surface layer strength is cellophane tape (Nichiban No.405 18m
(W width) 10cm in length is pressed on the coat layer with the thumb of the thumb while making close contact with the coat layer.
/ 5 seconds), the area of the ink receiving eyebrow adhered to the cellophane tape was less than 20%, ◎, 20 to 50% or less, 、, and more than 50%. These evaluation results are as shown in Table 1.

[0038]

[Table 1]

[0039]

The present invention is as described above. The thermal transfer image-receiving sheet according to the present invention is a through-hollow plastic pigment having at least one through-hole in the ink-receiving layer, which connects a surface layer of particles to an internal space. Since this plastic pigment has a hollow structure, excellent heat insulating properties and cushioning properties are obtained due to the hollow structure, and excellent ink absorption properties due to having fine pores in the penetrating structure.
(Oil absorbency) and the effect of anchoring ink.

Further, the thermal transfer image-receiving sheet of the present invention, in addition to the above-mentioned important functions as a thermal transfer image-receiving sheet, can further increase the surface strength by adjusting the addition ratio of the hollow plastic plastic pigment. Low density transferability, maximum density, graininess,
Excellent effects are obtained in all of the thermal transfer suitability such as dot reproducibility, surface layer strength, gradation, and high glossiness.

[Brief description of the drawings]

FIG. 1 is an electron micrograph of an example of a hollow hollow plastic pigment contained in an ink receiving layer of a thermal transfer image-receiving sheet of the present invention.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takeshi Kanazaki 7-34 Yodabashi-cho, Fuji-shi, Shizuoka Pref.

Claims (5)

[Claims] 1. A thermal-transfer image-receiving sheet having an ink-receiving layer provided on a base material, a hollow hollow plastic pigment having at least one through-hole in the ink-receiving layer as a filler connecting a surface layer of particles to an internal space. A thermal transfer image-receiving sheet comprising: 2. JI of through-hole hollow plastic pigment
The thermal transfer image-receiving sheet according to claim 1, wherein the oil absorption based on SK5101 is 150% or more. 3. The penetration hollow type plastic pigment present in the ink receiving layer contains 10% by weight of the solid content of 100% by weight of the total filler.
3. The thermal transfer image-receiving sheet according to claim 1, wherein the amount is not less than part by weight. 4. The thermal transfer image-receiving sheet according to claim 1, wherein the ink receiving layer has a ratio F / R of the solid weight R of the binder resin to the solid weight F of the entire filler of 1 to 5. 5. The thermal transfer image-receiving sheet according to claim 1, wherein the hollow hollow plastic pigment has a particle size of 0.5 μm or more.