JP2715435B2 - Heat transfer sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-receiving sheet for receiving a sublimable dye of a sublimation-type thermal transfer material.

[Prior art] A method in which a thermal transfer material provided with a dye layer containing a sublimable dye is heated by a thermal head, and the dye is sublimated and received by a heat-transferred sheet is capable of obtaining excellent gradation and image quality in recent years. It is rapidly spreading in color recording on OA terminals such as facsimile machines, printers, and copiers, television, and video recording. The heat transfer sheet used in the sublimation type thermal transfer system has a basic configuration in which a receiving layer for receiving a sublimable dye is provided on one surface of a substrate and a release layer is provided on the surface of the receiving layer. This release layer is provided for preventing the adhesion between the dye layer and the receptor layer, and as a method therefor, a method of providing a heat-resistant resin layer (JP-A-58-215398),
Roughening method of receiving layer (JP-A-57-107885), method of applying silicone grease (JP-A-59-165688), and containing a reaction cured product of amino-modified silicone and epoxy-modified silicone A method (JP-A-60-34898) and a method of providing a layer containing an amino-modified silicone (JP-A-62-294596) are known.

[Problems to be Solved by the Invention] However, the above-mentioned method has a drawback that the acceptability of the dye is insufficient, and the degree of dyeing varies depending on the type of the dye, so that a desired color tone cannot be obtained. Had. In addition, there is a disadvantage that the surface is sticky or falls off due to insufficient strength of the release layer.

Further, the method of mixing with a resin in order to supplement the strength of the coating film of the release layer has drawbacks such as insufficient dyeing properties and reduced release properties.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat transfer sheet having a release layer which does not have the above-mentioned disadvantages, that is, has no variation in the degree of dyeing, has a good releasing effect, and has excellent coating strength.

[Means for Solving the Problems] An object of the present invention is to provide a sublimation type thermal transfer material containing a sublimable dye containing a dye which sublimates by heating. A heat transfer sheet characterized by having a release layer mixed with a thermoplastic polyester resin containing 5 to 90% by weight of a modified organopolysiloxane having an alkylene group is used as the gist of the heat transfer sheet.

The heat transfer sheet of the present invention has, for example, a structure in which a receiving layer is provided on one surface of a sheet-like substrate, and a release layer is provided on the surface of the receiving layer. And those provided with a cushion layer in between. The sheet-shaped substrate is not particularly limited, but includes, for example, (a) synthetic paper (polyolefin-based, polystyrene-based, etc.), (b) fine paper, art paper, coated paper, cast-coated paper, wallpaper-backed paper, synthetic resin or emulsion impregnation. Natural fiber paper such as paper, synthetic rubber latex-impregnated paper, synthetic resin-containing paper, paperboard, or cellulose fiber paper; (c) various plastic films such as polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, methacrylate, and polycarbonate; Sheets can be used. Also, a laminate formed by any combination of the above (a) to (c) can be used.

As the constituent components of the receiving layer, those having various polyester copolymers as main components as those having good receptivity to sublimable dyes are preferably used. The polyester copolymer is obtained by polycondensing a dicarboxylic acid component and a glycol component, and is not particularly limited. The dicarboxylic acid component is an aromatic, aliphatic or alicyclic dicarboxylic acid, such as terephthalic acid, isophthalic acid, orthophthalic acid,
6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, succinic acid, glutaric acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dodecanedicarboxylic acid, azelaic acid, and sulfoterephthalate as a metal salt dicarboxylic acid Acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene 2,
Metal salts such as 7-dicarboxylic acid and 5 [4-sulfophenoxy] isophthalic acid. The glycol component to be reacted with the dicarboxylic acid is an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 12 carbon atoms, and specific examples thereof include ethylene glycol, 1,2-propylene glycol, , 3-propanediol, 1,
4-butanediol, neopentyl glycol, 1,6
-Hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-
Cyclohexanedimethanol, p-xylylene glycol, diethylene glycol, triethylene glycol and the like. Polyethylene glycol, polypropylene glycol, or polytetramethylene glycol may be used as a part of these glycol components. In particular, a polyester obtained by block copolymerizing a polytetramethylene glycol with the polyester copolymer comprising dicarboxylic acid and glycol is preferable as the receptor layer because both dye receptivity and cushioning property can be achieved.

The thickness of the receiving layer is not particularly limited, but is usually 0.5 μm or more and 20 μm or less, preferably 1.0 μm or more and 10 μm or less, and more preferably 2.0 μm or more and 7 μm or less. The substrate and the receiving layer are weathering agents, coloring agents, matting agents, antistatic agents, as long as the object of the present invention is not impaired.
A flame retardant, a heat resistant agent and the like may be dispersed and compounded. Further, the surface of the receiving layer may be subjected to a discharge treatment, an antistatic treatment, a matting treatment, or the like.

Lamination of the receiving layer on the substrate may be performed by any method,
There is no particular limitation. For example, there are a method of melt extrusion on a substrate sheet (extrusion lamination method), a method of dissolving in a solvent to coat on a substrate, a method of co-melt extrusion with a substrate, and biaxial stretching and heat treatment as necessary. In the present invention, any of the above methods may be used, but a co-melt extrusion method is preferred from the viewpoint of adhesion between the substrate and the receiving layer.

The modified organopolysiloxane having a polyoxyalkylene group (hereinafter, the modified organopolysiloxane having a polyoxyalkylene group is abbreviated as a silicone component) contained in the release layer provided on the surface of the receptor layer of the present invention is represented by the following general formula. The following shows various modified organopolysiloxanes containing as a structural unit.

(Where n is an integer of 1 to 5000, R is an alkylene group having 1 to 20 carbon atoms, a phenylene group, a cyclohexylene group, or an ether group, and POA is a polymer of an alkylene oxide having 1 to 20 carbon atoms. One or more selected ones are shown.) Specific examples include polyether-modified silicone, epoxy-polyether-modified silicone, amino-polyether-modified silicone, alkylaralkyl-polyether-modified silicone, carboxyl-polyether-modified silicone, Examples include fluorine / polyether-modified silicone. Polyether-modified silicone, amino-polyether-modified silicone and epoxy-polyether-modified silicone are preferred from the viewpoint of dyeing properties and color tone, and two or more of these may be used in combination. It is desirable that 30 to 500 parts by weight, preferably 50 to 300 parts by weight, more preferably 80 to 200 parts by weight, of the polyoxyalkylene group is added to the silicone with respect to 100 parts by weight of the silicone constituting the skeleton. The silicone component imparts toughness to the coating film, and is provided on the receiving layer as a mixture with a thermoplastic polyester resin from the viewpoints of dyeing properties, color tone, and adhesion to the receiving layer.

The thermoplastic polyester resin is obtained by polycondensation of a dicarboxylic acid component and a glycol component, and is not particularly limited. Specific examples thereof include the following.

As the dicarboxylic acid component, aromatic, aliphatic, alicyclic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid,
Adipic acid, sebacic acid, succinic acid, glutaric acid, 1,3
-Cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dodecanedicarboxylic acid, azelaic acid and the like. Further, a dicarboxylic acid containing a metal salt of a sulfonic acid group can be used as a copolymer component in order to make the polyester copolymer water-soluble or to impart aqueous dispersibility. Examples thereof include metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene 2,7-dicarboxylic acid and 5 [4-sulfophenoxy] isophthalic acid.

Examples of the glycol component to be reacted with the above-mentioned dicarboxylic acid include aliphatic glycols having 2 to 8 carbon atoms or 6 carbon atoms.
~ 12 alicyclic glycols, specific examples of which include ethylene glycol, 1,2-propylene glycol, and 1,3-
Propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,2-
Cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,
p-xylylene glycol, diethylene glycol, triethylene glycol and the like. Polyethylene glycol, polypropylene glycol, or polytetramethylene glycol may be used as a part of these glycol components. The polyester copolymer obtained from the dicarboxylic acid and the glycol component is water, an organic solvent,
And dissolved or dispersed in a mixture of water and an organic solvent. The polyester copolymer contains terephthalic acid and ethylene glycol as main components, and other dicarboxylic acids and glycol components are preferably copolymerized. A component (PET component) composed of terephthalic acid and ethylene glycol is preferably 40 to 95 moles in the polymer. %, Preferably 5
When the amount is 0 to 90 mol%, more preferably 60 to 85 mol%, it is particularly preferable since better dyeing properties and releasability can be obtained.

The content of the silicone component in the release layer is 5 to 90% by weight,
Preferably 10-80% by weight, more preferably 15-70% by weight
It is. If the amount of the silicone component is less than 5% by weight, the releasability is insufficient, and if it exceeds 90% by weight, the toughness of the release layer is insufficient.

The thickness of the release layer is not particularly limited, but is usually 0.01 μm to 5 μm.
It is preferable that the layers are laminated in a range of μm. Lamination of the release layer on the surface of the receiving layer is performed by applying a coating solution obtained by dissolving or dispersing the silicone component and the resin using water and various organic solvents by a known coating method, for example, a reverse coating method, a gravure coating method, a rod coating method. It can be carried out by applying and drying using a die coating method or the like.

In addition, in a case where the receiving layer is formed on the substrate by extrusion lamination or a method in which the substrate and the receiving layer are co-melt extruded and laminated, a release layer may be continuously applied after the receiving layer is laminated. Especially after the latter method, that is, after stretching the laminated sheet obtained by co-melt extrusion of the substrate and the receiving layer in the longitudinal direction,
A method in which a release layer is applied to the receiving layer side, stretched in the width direction after drying or while drying, and further subjected to a heat treatment is particularly preferable because the toughness of the coating film increases.

In the sublimation type thermal transfer material used in combination with the heat transfer sheet of the present invention, the sublimation dye used is a conventionally known sublimation dye, for example, Mikenton polyester
yellow-YL (Mitsui Toatsu, CIDispers Yellow-42),
Kayaset yellow-G (Nippon Kayaku, CIDispers Yellow
77), PTY-52 (Mitsubishi Kasei, CISolvent yellow 14-
1), Mikenton polyester Red BSF (made by Mitsui Toatsu, CID
ispers Red 111), Kayaset Red B (Nippon Kayaku, .CID
ispers Red B), PTR-54 (manufactured by Mitsubishi Kasei, CIdispers Re
d 50), Mikenton Polyester Blue FBL (Mitsui Toatsu, C.
I. Dispers Blue 56), PTB-67 (Mitsubishi Chemical, CIDispe)
rse Blue 241), Kayaset Blue 906 (Nippon Kayaku, CIS
olvent 112) and the like.

Next, specific examples of the method for producing a heat transfer sheet of the present invention will be described, but the present invention is not limited thereto. In a co-melt extrusion method in which two extruders are combined and combined in a short pipe and discharged from a die, a polyethylene terephthalate resin dried from one extruder and a receiving layer resin dried from the other extruder (for example, polyester copolyester) Is melt-extruded and then solidified by cooling to produce an unstretched composite sheet of polyethylene terephthalate and a receiving layer. 80 ~ 120 this sheet
C. and stretched 2.5 to 5 times in the longitudinal direction to obtain a uniaxially oriented sheet. A corona discharge treatment is applied to the receiving layer surface side of this sheet, and a coating liquid of a mixture of a silicone component and a resin (for example, a polyester copolymer) is applied to the treated surface. Next, the coated sheet is stretched 3 to 4.5 times in the width direction while being heated to 90 to 130 ° C., and subsequently guided to a heat treatment zone of 180 to 240 ° C. and heat-treated for 1 to 10 seconds. The sheet is cut into an appropriate size to form a heat transfer sheet.

[Effect of the Invention] In the present invention, by providing a release layer made of a mixture with a thermoplastic polyester resin containing a specific modified silicone on the receiving layer, the dyeing property is good and the dyeing property of the dye is not varied. A heat transfer sheet having a good color tone,
In addition, a heat transfer sheet excellent in the releasability from the dye layer and the toughness of the coating film could be obtained.

The heat-transferable sheet of the present invention has the above-described excellent effects, and is a transparent or opaque receiving sheet of a sublimation-type heat-sensitive transfer material for color recording or color recording of a television image in an OA terminal such as a facsimile, printer, or copier. It is preferably used as

[Method for Measuring Characteristics and Method for Evaluating Effect] The method for measuring characteristics and the method for evaluating effect in the present invention are as follows.

(1) Evaluation of dyeing properties, color tone, and releasability The sublimation-type thermal transfer material used in the evaluation was prepared by applying silicone oil to one side of a 6-μm biaxially oriented polyethylene terephthalate film to a thickness of 0.2 μm, and the other side. Was coated with the following composition so that the thickness after drying was 2 μm, and slit to an appropriate width.

Disperse dye 4 parts by weight Ethyl hydroxycellulose 6 parts by weight Methyl ethyl ketone 45 parts by weight Toluene 45 parts by weight The following three components were used alone to prepare a sublimation type thermal transfer material of three primary colors.

(Yellow) Kayaset yellow-G (Nippon Kayaku) (Cyan) Kayaset Blue-714 (Nippon Kayaku) (Magenta) Kayaset Red-B (Nippon Kayaku) This sublimation type heat-sensitive transfer material and heat transfer sheet are sharp color video. The printer was set on a printer GZ-P11, and a test pattern color image of 12 colors of a television was transferred at an applied voltage of 15 volts. The following evaluation was performed on this transferred image.

The dyeing property was visually determined based on the black density of the television image. The case where the color density similar to that of the television image was reproduced was evaluated as excellent, and the evaluation was made in four stages of good, acceptable, and unacceptable according to the color density. The color tone is visually judged for each of the 12 colors of the test pattern,
Acceptable and unacceptable evaluations were made, and good or better was judged to be acceptable. The releasability depends on the degree to which the sublimable dye dispersion layer of the thermal transfer material adheres to the heat transfer sheet after passing through the printer.
A three-point evaluation of x was performed. ○ indicates that no adhesion was observed, and only this level was accepted.

(2) Coating strength of release layer The surface of the coating of the release layer was rubbed with gauze 20 times under a load of 500 g, and then passed through a printer, and evaluated in the same manner as the above-mentioned releasability.

[Examples] Next, the present invention will be described based on examples.

Example 1 A biaxially oriented polyester film having a thickness of 100 μm (“Lumirror” manufactured by Toray Industries, Inc.) was used as a substrate, and the receiving layer was made of [terephthalic acid / isophthalic acid (80/20 mol%) and ethylene glycol]. Intrinsic viscosity obtained by condensation
70 dl / g of copolyester was used. The resin of the receiving layer is melt-extruded and laminated on the substrate so as to have a thickness of 3 μm. A release layer having the following composition is dissolved in water and dried on the surface of the receiving layer (130).
(2 ° C., 2 minutes) to give a heat transfer sheet by coating so as to have a thickness of 0.2 μm.

Addition of 100 parts by weight of polyethylene oxide, 50 parts by weight of polyether-modified silicone having a viscosity of 1000 cSt. An intrinsic viscosity of 0.65 dl / g consisting of [terephthalic acid / 5-Na-sulfoisophthalate (85/15 mol%) and ethylene glycol]
When the heat transfer sheet was evaluated according to the above evaluation method, the dyeing property and the color tone were excellent, and the releasability and the coating film strength were good.

Examples 2 and 3 Amino polyether-modified silicone having a viscosity of 800 cStokes (Example 2) having a silicone component added with 100 parts by weight of polyethylene oxide and 1.0 part by weight of amino group, 100 parts by weight of polyethylene oxide, epoxy group
A heat transfer sheet was prepared in the same manner as in Example 1 except that 1.5 parts by weight of an epoxy / polyether-modified silicone having a viscosity of 650 centistokes (Example 3) was used. All of the heat transfer sheets had good dyeing properties, excellent color tone, releasability, and good coating strength of ○.

Comparative Examples 1 and 2 Except that the silicone component was changed to an emulsion of dimethylpolysiloxane having a viscosity of 1,000 centistokes (Comparative Example 1) and an amino-modified silicone having a viscosity of 1200 centistokes (Comparative Example 2) having 1.5 parts by weight of amino groups added. A heat transfer sheet was prepared in the same manner as in Example 1. This heat transfer sheet was unsuitable as a heat transfer sheet because the dyeability and the color tone were acceptable and the releasability was Δ.

Examples 4 and 5 Comparative Examples 3 and 4 The mixing ratio of the polyester copolymer and the silicone component, which are the resin components of the release layer in Example 1, was 98/2 (Comparative Example 3) and 90 by the weight ratio of resin / silicone. / 10 (Example 4), 20/80
Example 1 (Example 5), except that 5/95 (Comparative Example 4) was used.
In the same manner as in the above, a heat transfer sheet was prepared. When the silicone component is less than the range of the present invention (Comparative Example 3), the releasability is x and when the silicone component exceeds the range of the present invention (Comparative Example 4).
Had a coating film strength of Δ. Only in the case of being within the range of the present invention (Examples 4 and 5), the dyeing property, the color tone were good to excellent, the releasability, and the coating film strength were at the level of ○.

Example 6 A polyethylene terephthalate having an intrinsic viscosity of 0.62 ld / g from one extruder using two extruders, using a co-melt extruder that merges and combines in a short pipe and discharges a sheet from a die.
[Terephthalic acid / having an intrinsic viscosity of 0.70 dl / g from the other extruder
Isophthalic acid (82/18 mol%) and ethylene glycol]
The polyester copolymer obtained by polycondensation is melt-extruded and cooled and solidified on a cast drum to obtain a polyethylene terephthalate polyester copolymer (thickness composition ratio).
95, a total thickness of 1000 μm) was prepared. This sheet was heated to 90 ° C. and stretched 3.5 times in the longitudinal direction to obtain a uniaxially oriented sheet. The polyester copolymer layer surface of the uniaxially oriented sheet is subjected to corona discharge treatment in air, and the treated surface is coated with the water-based paint of Example 1 and further stretched 3.5 times in the width direction while heating to 110 ° C. To a heat treatment zone at 220 ° C., and heat-treated for 5 seconds to obtain a heat transfer sheet having a thickness of about 100 μm. The thickness of the release layer is 0.2μ after heat treatment.
m. The heat-transferred sheet thus obtained exhibited excellent dyeing properties and color tone, excellent releasability, and excellent coating film strength of ○.

Claims (1)

(57) [Claims] 1. A heat-receiving sheet for receiving a sublimable dye of a sublimation-type thermal transfer material containing a dye which sublimates by heating, wherein the modified organopolysiloxane has a polyoxyalkylene group on the surface of the sublimable dye-receiving layer of the sheet. 5
A heat-transferable sheet comprising a release layer mixed with a thermoplastic polyester resin containing up to 90% by weight.