JPH08156432A - Heat transfer recording sheet - Google Patents

Abstract

PURPOSE: To obtain a high quality transferring picture by eliminating the flaking off, which causes picture defects, at the working of a receiving layer, the omission of print at the transferring of the picture, micro-blocking and the like by a method wherein the resin, the modulus of which has a specified value or less, and the resin, the adhesion of which to the adjacent layer is favorable, are mixed with at least one layer between whitening layers. CONSTITUTION: On a base material 1, a receiving layer 2, which can thermally transfer on the paper to be recorded, is provided. The receiving layer 2 consists of a dyeing layer 3, which receives a coloring matter from a colorant layer, whitening layers 4 and 5. The resin, the 100% modulus in accordance with JIS-K-6301 of which is 100kg/cm<2> or less, and the resin, the adhesion of which to the adjacent layer is favorable, re added together with white pigment to the whitening layer 5. Further, a bonding layer 6 is provided on the whitening layer 5. Thus, the flaking off, which causes picture defects, at the working of the receiving layer 2, the following omission of print at the transferring and micro-blocking are eliminated, resulting in allowing to transfer a high quality transferring picture to general-purpose paper having wide use application.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording sheet, and more particularly to a thermal transfer recording sheet in which a general-purpose plain paper can be used as a recording paper.

[0002]

2. Description of the Related Art Conventionally, a heating means such as a thermal head is used to heat a volatile or heat diffusible dye from a coloring material layer, and a resin having a dyeing property to these dyes is a main constituent. A sublimation type thermal transfer recording system is known in which an image is transferred onto an image receiving layer to form an image on the image receiving layer. Further, in this method, a heat-melt transfer image-receiving layer is provided on a sublimation type thermal transfer recording sheet, the heat-melt transfer image-receiving layer is first transferred to a recording material, and then the transferred image-receiving layer is provided with a coloring material. A sublimation-type thermal transfer recording sheet is known, which is devised so that a general-purpose plain paper can be used as a recording material by transferring a dye from the layer (JP-A-63-170091).
JP-A-64-87390, etc.). Further, sublimation type thermal transfer recording in which the transferable image-receiving layer is separated into a dyeing layer which is dyed with a dye and a white hiding layer for increasing the whiteness of the printed area so that a deep image can be produced. Sheets have also been proposed (Japanese Patent Laid-Open No. 5-139056).
(See the official gazette).

[0003]

When such a general-purpose plain paper which is generally commercially available is used as the recording material, first, the heat-melt transferable image-receiving layer of the thermal transfer recording sheet is superposed on the plain paper, Heat from the opposite side of the sheet substrate,
It is necessary to melt-transfer the heat-melt transferable image-receiving layer from a base material onto plain paper.

However, the heat-transferable image-receiving layer having the dyeing layer and the white hiding layer together is fragile, and in order to obtain a product,
When the thermal transfer recording sheet was slit or rolled, the image receiving layer was sometimes cracked or bent, and the image receiving layer was sometimes peeled off from the base material to cause foil peeling. Further, when an image is formed by using this image receiving layer, there is also a problem that it becomes difficult to obtain a high quality image because it causes blocking and white spots.

[0005]

The object of the present invention is to soften the white hiding layer and to improve the adhesiveness with an adjacent layer, so that the image receiving layer does not fall off during processing, and thus, during printing, It is an object of the present invention to provide a thermal transfer recording sheet having an image receiving layer which is free from blocking, white spots and the like and which provides an excellent image of high quality.

A further object of the present invention is to provide a thermal transfer sheet which does not cause problems such as peeling of the image receiving layer during normal handling and is capable of thermal transfer with excellent cutting performance when heat is applied. That is, the gist of the present invention is a thermal transfer recording sheet having a substrate and an image-receiving layer transferable by heat formed on the substrate, the image-receiving layer having at least a dyeing layer and a white hiding layer, The white hiding layer is composed of a single layer or a plurality of layers, and at least one of the white hiding layers is JI
100% modulus specified in SK-6301 is 1
A thermal transfer recording sheet, characterized by containing a resin having a pressure of not more than 00 Kg / cm ² and a resin having good adhesion between adjacent layers.

The present invention will be described in detail below. As the base material of the thermal transfer recording sheet of the present invention, the same base material as that used in the conventional thermal transfer sheet can be used as it is, and other materials can also be used,
There is no particular limitation. Specific examples of preferred substrates include, for example, thin paper such as glassine paper, condenser paper, paraffin paper, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, Examples thereof include plastics such as ionomers and base materials obtained by combining these plastics with the above-mentioned paper.

The thickness of this substrate can be appropriately changed depending on the material so that its strength, heat resistance and the like are appropriate, but the thickness is preferably 3 to 100 μm. An image receiving layer that can be transferred onto a recording paper by heat is provided on a base material. In the present invention, the image receiving layer is composed of two or more layers including a dyeing layer and a white hiding layer. For example, as shown in FIG. 1, in an image receiving layer (2) provided on a base material (1), a dyeing layer (3) mainly for receiving a dye from a color material layer is provided on the base material, A white concealing layer containing a white pigment directly or through another layer to give the whiteness of the transferred image is provided, or two or more layers are provided as shown in (4) and (5) of FIG. Further, an adhesive layer (6) may be provided on the white hiding layer.

Each layer of the image receiving layer usually contains a resin and fine particles as main components. As the resin used for the dyeing layer, saturated polyester resin, acrylic resin, methacrylic resin, styrene resin, polycarbonate resin, cellulose acetate,
Polyvinyl acetal resin, polyvinyl phenyl acetal resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, polyarylate resin, AS resin or a crosslinked product of the above resin, which has a dyeing property to a vaporizable or heat diffusible dye. And may be used alone or in combination. As the fine particles to be mixed and used in the dyeing layer, for inorganic particles, for example, silica, calcium carbonate, alumina white, barium sulfate, etc., and as organic particles,
Examples thereof include silicone resins, urea resins, benzoguanamine resins, polystyrene resins, polymethylmethacrylate resins, and microcapsules. The particle size of these fine particles is preferably 0.01 to 10 μm. It is particularly preferably 0.02 to 5 μm. The amount of fine particles added to the dyeing layer is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the resin.
Further, the coating amount of the dyeing layer is preferably 1 to 10 g / m ² .

In the present invention, at least one layer of the white concealment layer is made of a resin having a 100% modulus of 100 Kg / cm ² or less specified by JIS-K-6301 and a resin having good adhesiveness to an adjacent layer. It is contained together with a white pigment (hereinafter, this layer is abbreviated as "soft white hiding layer"). JI
100% modulus specified in SK-6301 is 1
As the resin having a pressure of 00 kg / cm ² or less, ethylene-
Examples thereof include vinyl acetate-based copolymer resins, styrene-butadiene-based copolymer resins, urethane-based resins, etc., and olefin-based copolymer resins such as ethylene-vinyl acetate-based copolymer resins and styrene-butadiene-based copolymer resins are particularly desirable. .
The weight average molecular weight of the olefin-based copolymer resin is preferably in the range of 100,000 to 500,000, and particularly preferably in the range of 200,000 to 300,000. Examples of the resin having good adhesiveness to the adjacent layer include polyester resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, and the like, and acrylic resin is particularly preferable. The resin having good adhesiveness preferably has a weight average molecular weight in the range of 10,000 to 200,000, particularly 30,000 to 10
The range of ten thousand is preferable. Furthermore, the glass transition point is 40 ° C to 9 ° C.
It is preferably in the range of 0 ° C, particularly preferably 50 ° C to 70 ° C.

The soft white concealing layer is used by mixing the above-mentioned two kinds of resins, and the adhesion between a resin having a 100% modulus defined by JIS-K-6301 of 100 Kg / cm ² or less and an adjacent layer. The mixing ratio of the resin having good properties is preferably in the range of 10/90 to 90/10 by weight,
The range of 30/70 to 70/30 is more preferable. JIS
-100% modulus specified in K-6301 is 10
When the amount of the resin is 0 Kg / cm ² or less, the flexibility of the image receiving layer is good and foil peeling is reduced, but the adhesiveness with an adjacent layer is reduced, so that only the dyeing layer may not be transferred during transfer of the image receiving layer. is there. Conversely, 10 specified in JIS-K-6301
If the amount of the resin having a 0% modulus of 100 Kg / cm ² or less is too small, the flexibility is insufficient and foil peeling easily occurs.

In order to obtain whiteness, a white pigment, which is usually used in a white hiding layer, may be added to the above binder. Examples of the white pigment include titanium oxide, zinc oxide, calcium carbonate, talc and clay, which can be used alone or in combination. The particle size of the white pigment is
0.01-10 micrometers is preferable and 0.02-5 micrometers is more preferable. The addition amount is 50 with respect to 100 parts by weight of the resin.
To 300 parts by weight is preferable, and 80 to 2 is more preferable.
It is 00 parts by weight. In order to further increase the whiteness, various fluorescent whitening agents can be added. The coating amount of the soft white hiding layer is suitably 20 g / m ² or less, more preferably 3 to 10 g / m ^2.

When the white hiding layer is composed of two or more layers, the white hiding layers other than the soft white hiding layer use the same white pigment and the same resin as that used for the dyeing layer. The amount of the white pigment added is preferably 50 to 300 parts by weight, and more preferably 80 to 200 parts by weight. To further increase the whiteness, various fluorescent whitening agents can be added. Generally, the coating amount of the white hiding layer is appropriately 20 g / m ² or less, more preferably 3 to
It is 10 g / m ² .

In addition to the above resins and fine particles, various releasing agents may be added to the image-receiving layer of the present invention for the purpose of preventing blocking with the color sheet color material layer. Further, in order to facilitate the releasability of the dyeing layer of the present invention and the substrate at the time of thermal transfer, a silicone-based, ketone resin-based, polyvinyl acetal resin-based release layer or the like may be provided on the surface of the substrate, or In order to improve the adhesiveness between the recording paper and the image receiving layer, an adhesive layer (6) may be provided on the image receiving layer as shown in FIG. For the adhesive layer, a thermoplastic resin having good transferability at the time of heat may be used. Thermally expandable microcapsules may be added to the adhesive layer in order to eliminate the feeling of image roughness (missing print) due to the unevenness of the recording paper surface.

All of the image-receiving layers contain fine particles in an amount of 25 parts by weight or more based on 100 parts by weight of the resin in order to improve edge cutting and to obtain a transferred image of high quality. However, even if the fine particle content of the specific layer is out of this range, the expected effect can be obtained as long as the total fine particle content of the image receiving layer is within the predetermined range. Also, the addition amount of fine particles including the white pigment is
Usually, up to 200 parts by weight can be added to 100 parts by weight of the resin of the image receiving layer. If too much, the image receiving layer becomes brittle,
There is a high possibility of peeling from the base material or blocking with the color sheet during recording after transfer to the material to be transferred. On the other hand, if the amount is too small, the film strength of the image receiving layer will be too high and the cutting property will be poor. Therefore, 60 to 20 relative to 100 parts by weight of resin
The amount is more preferably 0 part by weight, further preferably 80 to 170 parts by weight. The ratio of resin to particles in the entire image receiving layer is determined as follows. First, with respect to all the layers constituting the image receiving layer, the number of parts by weight of the fine particles to 100 parts by weight of the resin in the layer is multiplied by the thickness of the layer. Then, the multiplied results are summed and the total number is divided by the total thickness of the image receiving layer. This makes it possible to obtain the averaged addition rate of fine particles as the image receiving layer.

The image receiving layers such as the dyeing layer, the white hiding layer and the adhesive layer are usually applied and formed as a coating liquid. An organic solvent suitable for each resin may be used as the solvent used for the coating liquid prepared by using the resin, fine particles, additives and the like. In order for the fine particles (including the white pigment) in the image receiving layer to sufficiently exert their effects, it is important that the fine particles are sufficiently dispersed in the image receiving layer. For that purpose, it is necessary to sufficiently disperse the fine particles when preparing a coating liquid described later for forming the image receiving layer. A well-known dispersion method may be used for the dispersion, for example, a homogenizer, a paint conditioner, a sand grind mill, or the like may be used. Further, a small amount of additives may be added for the purpose of improving the storage stability and redispersibility of the coating liquid.

The method of forming the image-receiving layer of the present invention on the substrate can be selected from the commonly used methods, for example, reverse roll coater, gravure coater, rod coater, air doctor coater, die coater. And a method using a gravure printing machine (for details of these, see “Coating Method” by Yuji Harazaki, published by Maki Shoten 1979), and particularly preferably, coating by a gravure printing method is used. When the coloring material dyeing layer is formed by coating a plurality of times, the above-mentioned coating methods may be arbitrarily combined. The coating amount of the image receiving layer is usually 1 to 30 g / m ² as a dry coating amount for all layers, preferably 2 to
It is 20 g / m ² .

As the vaporizable or heat diffusible dye used in the color material layer for thermal transfer recording used together with the image receiving layer of the present invention, known azo type, anthraquinone type, nitro type,
Various nonionic dyes such as styryl-based, naphthoquinone-based, quinophthalone-based, azomethine-based, coumarin-based, and condensed polycyclic-based dyes are used. As a form of forming the thermal transfer recording sheet of the present invention, for example, as shown in FIG. 2, an image receiving layer (2) capable of thermal transfer is provided on the same substrate, and yellow (7), magenta ( 8), cyan (9)
A color material layer such as the above is formed. According to this method, since both the image receiving layer and the color material layer are integrated with the thermal transfer recording sheet, no extra operation such as exchanging the cassette during printing is required, and the image is transferred onto the recording paper. It is also possible to limit the image receiving layer portion to only the image portion, which is very easy and is preferable. However, the present invention is not limited to this, and the entire image receiving layer may be transferred. Further, a sheet coated with only the image receiving layer of the present invention and a color sheet having only a color material layer are used in combination to transfer the image receiving layer. The image transfer can be performed by another operation. Therefore, the thermal transfer recording sheet of the present invention includes various cases as described above.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples, but the examples are not intended to limit the present invention as long as the gist thereof is not exceeded. Example-1 A thermal transfer recording sheet having the structure shown in FIGS. 1 and 2 was produced. (A) Preparation of dyeing layer, etc. Vinyl chloride-vinyl acetate copolymer resin (trade name: UCAR
-VYHD, manufactured by Union Carbide) 100 parts by weight,
Silicone resin fine particles (trade name: Tospearl 120, average particle size 2 μm, manufactured by Toshiba Silicone Co., Ltd.) 25 parts by weight, toluene 200 parts by weight, methyl ethyl ketone 200 parts, and amino-modified silicone as a release agent (product name: KF-
393, manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare a dyeing layer coating solution of 5 parts by weight. Also, 100 parts by weight of vinyl chloride-vinyl acetate copolymer resin (trade name: UCAR-VROH, manufactured by Union Carbide), titanium oxide fine particles (trade name: Taipek CR-60, average particle size 0.3 μm, manufactured by Ishihara Sangyo Co., Ltd.) A white hiding layer coating liquid consisting of 200 parts by weight and 500 parts by weight of methyl ethyl ketone was prepared.

In a gravure printing machine, a biaxially stretched polyethylene terephthalate film (thickness of 4.5 μm) having a back surface of the ink coating surface subjected to heat-resistant lubricity treatment was first coated with a dry coating amount of 3
to prepare a Somegiso (3) so that g / m ^2, dry coating amount thereon is overcoated the white hiding layer (4) so that 5 g / m ^2, the total dry coating Amount is 8g / m
^Two image receiving layer coated parts (2) were prepared. Fine particles per 100 parts by weight of the resin in the image receiving layer (2) are 25 parts by weight in the dyeing layer (3), 200 parts by weight in the white hiding layer (4), and 148 parts by weight as a whole. .

(B) Preparation of soft white hiding layer Ethylene-vinyl acetate copolymer resin (100% modulus 21 Kg / cm ² Trade name: Elvalloy 741, manufactured by Mitsui DuPont Polychemical Co., Ltd.) 50 parts by weight, acrylic resin (commodity) Name: Dianal LR-158, manufactured by Mitsubishi Rayon Co., Ltd. 50 parts by weight, titanium oxide (trade name: Taipaque C)
R-60, average particle size 0.3 μm, Ishihara Sangyo Co., Ltd.) 200
Parts by weight, and a soft white hiding layer coating solution consisting of 500 parts by weight of toluene was applied to the white hiding layer (4) prepared in (a) above with a gravure printing machine to give a dry coating amount of 4 g / m ² . And coated so that a flexible white hiding layer (5) was prepared.

(C) Preparation of adhesive layer Polyacrylic ester resin solution (weight ratio of methyl methacrylate: methyl acrylate: methacrylic acid 6
0: 3010 copolymer resin, glass transition point: 76 ° C., solid content 25%, molecular weight 30,000 to 50,000, 500 parts by weight, microcapsules (trade name: Matsumoto Microsphere F-
30 VSD, manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.), 100 parts by weight of an adhesive layer coating liquid consisting of 400 parts by weight of isopropyl alcohol was applied to the soft white hiding layer (5) prepared in (b) above with a gravure printing machine. An adhesive layer was prepared so that the dry coating amount was 3 g / m ² .

(D) Preparation of Coloring Material Layer Adjacent to the coated portion of the above coloring material dyeing layer Yellow coloring material layer coating liquid: Yellow dye (PTY52, Mitsubishi Chemical) represented by the following structural formula (A). 5 parts by weight,
Phenoxy resin (trade name; PKHJ, manufactured by Union Carbide Co.) 10 parts by weight, methyl ethyl ketone 90 parts by weight,
A coating liquid consisting of 10 parts by weight of isopropyl alcohol.

[0024]

Embedded image

Magenta color material layer coating liquid: the following structural formula (B)
A coating solution comprising 5 parts by weight of a magenta dye (PTR-63, manufactured by Mitsubishi Chemical Corporation) represented by, 10 parts by weight of a phenoxy resin, 90 parts by weight of methyl ethyl ketone, and 10 parts by weight of isopropanol.

[0026]

Embedded image

Cyan colorant layer coating liquid: 5 parts by weight of a cyan dye (PBK, manufactured by Mitsubishi Chemical Co.) represented by the following structural formula (C), 10 parts by weight of phenoxy resin, and 9 of methyl ethyl ketone.
A coating liquid consisting of 0 parts by weight and 10 parts by weight of isopropanol.

[0028]

Embedded image

[0029] Each of the three color coating liquids of
Color material layer (7) with a dry coating amount of about 1 g / m ² each
A test thermal transfer sheet having (9) was prepared. (E) Transfer recording test The image receiving layer obtained above was overlaid on a high-quality paper (manufactured by Kanzaki Paper Co., Ltd.) having a basis weight of 200 g, and a partial grace type line thermal head having a heating resistor density of 5.4 dots / mm was used. And transferred under the following conditions, and the results are shown in Table 1.

[0030]

[Table 1] Recording line density 5.4 lines / mm Thermal head applied power 0.20 W Thermal head applied pulse width Image receiving layer transfer: 14.5 msec Printing recording: 14.5 msec Evaluation item Folding resistance: Image receiving layer Was bent 180 degrees, and cracks and foil drop were visually observed and evaluated. Evaluation criteria: ○ Good × Poor Transferability: The state of transfer to high-quality paper was visually observed and evaluated. Evaluation criteria: o Good x bad Print density: The density of the printed matter printed under the above print recording conditions was measured with a reflection densitometer (Macbeth RD-927 type, manufactured by Macbeth).

Comparative Example-1 In the soft white hiding layer used in Example-1, the resin was changed to only ethylene-vinyl acetate copolymer resin (trade name: Elvalloy 741, manufactured by Mitsui DuPont Chemical Co., Ltd.). A test was conducted in the same manner as in Example-1, and the results are shown in Table-1.

Comparative Example-2 In the soft white concealing layer used in Example-1, the resin was changed to acrylic resin (100% modulus value does not exist, trade name: Dianal LR-158, manufactured by Mitsubishi Rayon Co., Ltd.). Tests were conducted in the same manner as in Example 1 except that the results were shown in Table 1.

Comparative Example-3 In the soft white hiding layer used in Example-1, the resin was a vinyl chloride / vinyl acetate copolymer resin (100% modulus value was not present, glass transition point: 65 ° C., trade name: VR
OH, manufactured by Union Carbide Co., Ltd.), and tests were conducted in the same manner as in Example 1 except that the solvent was changed to methyl ethyl ketone, and the results are shown in Table 1.

[0034]

[Table 2]

[0035]

The sublimation type thermal transfer recording sheet of the present invention comprises:
When the image receiving layer is processed, there is no foil loss that causes image defects, and there is no printing omission during image transfer or microblocking, so that a high-quality transferred image can be transferred to a wide range of general-purpose paper.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a form of formation of a thermal transfer recording sheet according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a portion in which an image receiving layer having an adhesive layer of the thermal transfer recording sheets used in Example-1 and Comparative Examples-1 to 3 is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Image receiving layer 3 Dyeing layer 4 White hiding layer 5 Flexible white hiding layer 6 Adhesive layer 7 Yellow coloring material layer 8 Magenta coloring material layer 9 Cyan coloring material layer

Claims (4)

[Claims] 1. A thermal transfer recording sheet having a substrate and an image-receiving layer transferable by heat on the substrate, wherein the image-receiving layer has at least a dyeing layer and a white hiding layer, and the white hiding layer is a single layer. A resin having a layer or a plurality of layers, and at least one of the white hiding layers has a good adhesiveness between a resin having a 100% modulus of 100 Kg / cm ² or less defined in JIS-K-6301 and an adjacent layer. A sheet for thermal transfer recording, comprising: 2. The standard 10 defined in JIS-K-6301.
The thermal transfer recording sheet according to claim 1, wherein the resin having a 0% modulus of 100 kg / cm ² or less is an olefin copolymer resin. 3. A resin having good adhesiveness to an adjacent layer,
3. A thermal transfer recording sheet according to claim 1, which is an acrylic resin. 4. A color material layer is provided on the base material in addition to the image receiving layer.
Alternatively, the thermal transfer sheet described in 3.