JPH0323990A - Thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer image receiving sheet possible to perform high speed recording and capable of forming a high density transfer image of high resolving power without using a release agent by forming a dye receiving layer from a polymer, to which a releasable segment is grafted, having good dyeing affinity to a dye. CONSTITUTION:A thermal transfer image receiving sheet consists of a base material sheet and the dye receiving layer provided to at least one surface of said sheet from a releasable graft copolymer. The polymer forming the dye receiving layer is one having at least one releasable segment and the releasable segment is bonded to the main chain of the polymer as a side chain by graft reaction. The main chain is integrally bonded to the base material sheet. By synthesizing these actions, the releasable segment becomes rich in the surface of the dye receiving layer to develop good releasability. Further, by selecting a main chain having good dyeing affinity to a dye, the excellent dyeing affinity to a dye can be imparted.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thermal transfer image-receiving sheet 1 useful in a thermal transfer method using a sublimable dye (thermally transferable dye). The purpose of the present invention is to provide a thermal transfer image-receiving sheet that can perform high-speed recording without using it and can form transferred images with high density and high resolution.

(Prior art and its problems) Inkjet methods, thermal transfer methods, etc. have been developed as methods for providing excellent monochrome or full-color images simply and at high speed in place of conventional general printing methods. Among these, the so-called sublimation thermal transfer method, which uses sublimable dyes, is the most excellent as it has excellent continuous gradation properties and provides full-color images comparable to color photographs.

The thermal transfer sheet used in the above-mentioned sublimation type thermal transfer method forms a dye layer containing a sublimable dye on one side of a base sheet such as a polyester film, and on the other side, a dye layer containing a sublimable dye is formed on one side of the base sheet to prevent the thermal head from sticking. Those with a heat-resistant layer provided on the other side are generally used.

The dye layer surface of such a thermal transfer sheet is placed on the image receiving sheet 1~ having an image receiving layer made of polyester resin etc., and the dye in the dye layer is heated in an imagewise manner from the back side of the thermal transfer sheet 1 with the thermal head 1~. Moving to the image receiving sheet 1, a desired image is formed.

The thermal transfer method described above has the excellent advantage of being able to vary the density of the image by changing the temperature of the thermal head.
If the temperature of the thermal head is raised, the binder forming the dye layer will soften and stick to the image receiving sheet, causing the inconvenience that the thermal transfer sheets 1~ and the image receiving sheet will adhere to each other. A problem arises in that the dye layer is peeled off during peeling and transferred to the surface of the image receiving sheet 1 as it is.

One way to solve this problem is to include a release agent such as silicone oil in the dye-receiving layer of the image-receiving sheet, but since the silicone oil is liquid at room temperature, it may cause problems during storage. However, they have the disadvantage that they stand out on the surface of the receptive layer, causing problems of blocking and contamination. on the other hand,
Although there are methods using thermosetting silicone oil, these methods require heat treatment after the formation of the receptor layer, which poses a problem in that the production process is extremely complicated.

Furthermore, if a relatively large amount of silicone is added in order to impart sufficient releasability to the receiving layer, problems arise such as a decrease in dye receptivity, discoloration of the image receiving sheet, and deterioration of storage stability.

Furthermore, it is conceivable to form the dye-receiving layer with a silicone-acrylic block copolymer resin that itself has mold-releasing properties, but the receptor layer made of this resin lacks adhesion to the base sheet and dye receptivity. Moreover, since it is hard and lacks cushioning properties, there is a problem in that white spots occur during printing, making it impossible to form images with high density and high resolution.

Accordingly, an object of the present invention is to provide a thermal transfer image-receiving sheet 1 which enables high-speed recording and can form transferred images with high density and high resolution without using a release agent when forming a receiving layer.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a thermal transfer image-receiving sheet in which a dye-receiving layer is provided on the surface of a base sheet, in which the dye-receiving layer comprises a polysiloxane segment, a fluorocarbon segment, and a long-chain alkyl segment bonded to the main chain. A thermal transfer sheet comprising a Graph 1 cobolimer having at least 1 fffi releasable segment selected from the following.

(Function) By forming the dye-receiving layer from a polymer with good dye-staining properties and having mold-releasing segments shown in graph 1, the mold-releasability, dye-staining properties, and properties can be improved without using a mold release agent. An image-receiving sheet having excellent adhesion to the base material etc. can be obtained.

That is, in the present invention, the polymer for forming the dye-receiving layer is a polymer having at least one type of releasable segment l. A releasable segment 1 is bonded to a certain polymer as a side chain in graph 1.

The releasable segment 1 of such a polymer itself generally has low compatibility with the main chain of the polymer. Therefore, when a dye-receiving layer is formed from such a polymer, the releasable segments tend to undergo microphase separation from the dye-receiving layer and bleed onto the surface of the dye-receiving layer. On the other hand, the main chain is integrated and adhered to the base sheet 1. As a result of these effects working together, the surface of the dye-receiving layer becomes rich in releasable segments as shown in the second figure, and exhibits good releasability. However, the releasable segment does not separate from the dye-receiving layer by the main chain, and therefore the releasable segment does not migrate to the surface of other articles. In addition, by selecting a main chain having good dye-dyeability, it is possible to impart excellent dye-dyeability.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The thermal transfer image-receiving sheet of the present invention comprises a dye-receiving layer made of releasable graph 1 cobolimer on at least one surface of a base sheet.

The base sheet used in the present invention includes synthetic paper (polyolefin type, polystyrene type, etc.), high quality paper, art paper,
Coated paper, Cast 1 coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex-containing paper, synthetic resin internally added paper, paperboard, etc., cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene Films or sheets of various plastics such as terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used, and white opaque films formed by adding white pigments and fillers to these synthetic resins or foamed films can be used. Foaming seams 1, etc. can also be used, but are not particularly limited. or,"
A laminate made of any combination of the two base sheets can also be used. Typical examples of laminates include cellulose fiber paper and synthetic paper, cellulose fiber paper and plastic film, or synthetic paper of sheets 1 to 1. The thickness of these base sheets may be arbitrary, for example, 10 to 300L.
The thickness is generally about Lm.

When the base material sheet 1 as described above has poor adhesion to the receptor layer formed on its surface, it is preferable to subject the surface thereof to a brimer treatment or a corona discharge treatment.

The dye-receiving layer formed on the surface of the base sheet 1 is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image.

In the present invention, the polymer forming the dye-receiving layer has graph 1. This is Kobo Limer.

As the polymer for the main chain, any conventionally known polymer having a reactive functional group can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxybutyl cellulose, methyl cellulose, and cellulose acetate. ,
Cellulose resins such as cellulose acetate, acrylic resins, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acecool, polyvinyl pyrrolidone, vinyl resins such as polyacrylamide, polyamide resins, polyurethane resins, polyesters Among these, acrylic, vinyl, polyester, polyurethane, polyamide, or cellulose resins are particularly preferred from the viewpoint of dye dyeability.

The releasable graft copolymer used in the present invention can be synthesized by various methods, and one preferred method is to add functional groups present in the main chain after formation of the main chain.
A method of reacting with a mold-releasing compound having a functional group that reacts with this may be mentioned.

Examples of the releasable compound having the above-mentioned functional group include the following compounds.

(al polysiloxane compound?) In the above formula, a part of the methyl group may be substituted with another alkyl group or an aromatic group such as a phenyl group.

(b) Carbon fluoride compound (8) (1;.F, ■C 2H 40 H (9)
C6F,3(;2H.OH CF3 \ (10) CI”C,,.F2oC2H40H/ CF3 11 C8F.7C2H40H 12 C,oF2,C2H40H 13) C8F,,SO2N(C:2H5)C2H4
0H141C. F,7302N((:2H51C2
H40H15 C6F,3COOH 16 C. F,3COCl 17 C:8F,7C:2H4SH (c) Long chain alkyl compounds Higher fatty acids such as lauric acid, myristic acid, valmitic acid, stearic acid, oleic acid, linoleic acid, and their acid halides, nonyl alcohol, fog higher alcohols such as alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, linoleyl alcohol, and ricinoleyl alcohol, higher aldehydes such as cabraldehyde, lauric aldehyde, myristic aldehyde, and stearic aldehyde, decylamine, Higher amines such as laurylamine and cetylamine.

The above examples are merely illustrative, and various other reactive mold-releasing compounds are available from Shin-Etsu Chemical, etc., and any of them can be used in the present invention. Particularly preferred is a monofunctional release compound having one functional group in one molecule, and when a polyfunctional compound having two or more functionalities is used, the graft copolymer obtained is unfavorable because it tends to gel.

The relationship between the functional mold-releasing compound and the resin 11 12 as exemplified above is as shown in Table 1 below, where X represents the functional group of the mold-releasing compound and Y represents the functional group of the polygon polymer. Of course, the relationship between X and Y may be reversed, or they may be used in combination, and the invention is not limited to these examples as long as they react.

Table 1 Another preferred manufacturing method is to react the functional mold-releasing compound with a vinyl compound having a functional group that reacts with the functional mold-releasing compound to form a monomer having a mold-releasing segment. Similarly, the desired graph can be obtained by copolymerizing with a vinyl monomer!・You can obtain Kobo Rimer.

In yet another preferred production method, the exemplified compound (7) is added to a polymer having an unsaturated double bond in its main chain, such as an unsaturated polyester or a copolymer of a vinyl monomer and a diene compound such as butadiene. Examples include a method of grafting by adding a mercapto compound such as ) or the above-mentioned releasable vinyl compound.

The above are examples of preferred production methods, and the present invention can of course also use graft copolymer produced by other methods.

The content of the releasable segment in the above polymer is such that the amount of the releasable segment in the polymer is 3 to 60% by weight.
If the amount of the releasable segment is too small, the releasability will be insufficient, while if it is too large, the migration of the dye and the strength of the film will decrease, and the discoloration and storage stability of the dye will be affected. This is not desirable as it causes problems.

Thermal transfer image-receiving sheets 1 to 1 of the present invention are prepared by dissolving the above-mentioned resin with necessary additives on at least one side of the base material sheet in an appropriate organic solvent, or by dissolving the above-mentioned resin in an appropriate organic solvent or water. For example, a gravure printing method,
The dye-receiving layer is obtained by coating and drying by a forming method such as a screen printing method or a reverse roll coating method using a gravure plate.

When forming the dye-receiving layer, conventionally known receptor layer-forming resins can also be used in combination. When these known resins are used together, it is preferable that the graft copolymer accounts for 30% by weight or more of the entire resin.

When forming the above-mentioned receptor layer, pigments and fillers such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely powdered silica are used to improve the whiteness of the receptor layer and further enhance the clarity of the transferred image. Can be added. or,
In order to further improve the resistance to change and fading of the transferred image formed on the receptor layer, especially the resistance to indoor change and fading and the resistance to dark place, ultraviolet absorbers and antioxidants can be added to the receptor layer.

The dye-receiving layer formed as described above may have any thickness, but generally has a thickness of 1 to 50 μm. Although such a dye-receiving layer is preferably a continuous coating, it may also be formed as a discontinuous coating using a resin emulsion or resin dispersion.

Further, the image receiving sheet of the present invention can be applied to various uses such as thermal transfer recording sheets capable of thermal transfer recording, cards, transmission type manuscript preparation sheets, etc. by appropriately selecting the base material sheet.

Furthermore, in the image receiving sheet 1 of the present invention, a cushion layer can be provided between the base sheet and the receiving layer if necessary, and by providing such a cushion layer, image information can be improved with less noise during printing. Corresponding images can be transferred and recorded with good reproducibility.

Furthermore, a slippery layer may be provided on the back surface of the base sheet 1. Examples of the material for the slipping layer include methacrylate-1 resins such as methyl methacrylate or corresponding acrylate resins, vinyl resins such as vinyl chloride-vinyl acetate copolymers, and the like.

Furthermore, it is also possible to provide a detection mark on the image receiving sheet 1. The detection mark is extremely convenient when positioning the thermal transfer sheet and the image-receiving sheet, and for example, a detection mark that is detected by a phototube detection device can be provided by printing on the back surface of the base sheet.

The thermal transfer sheet 1 used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is one in which a dye layer containing a sublimable dye is provided on paper or polyester film, and is a conventional thermal transfer sheet. Any of these can be used as is in the present invention.

The means for applying thermal energy during thermal transfer using the image-receiving sheet of the present invention may be any conventionally known means, such as a thermal printer (e.g., Video Printer VY-100 manufactured by Kikki Hitachi, Ltd.). By controlling the recording time using a recording apparatus such as the above, the desired purpose can be sufficiently achieved by applying thermal energy of about 5 to L O O m J/mm'.

(Effects) According to the present invention as described above, by forming the dye-receiving layer from a specific resin, the dye-receiving layer can be formed without using a mold release agent.
An image-receiving sheet having excellent mold releasability, dye stainability, adhesion to a substrate, and cushioning properties can be obtained.

Therefore, the thermal transfer image receiving sheet 1 can prevent fusion with the thermal transfer sheet during transfer without using a release agent that causes various problems, and can form images with high density and high resolution at high speed.
・Provided.

(Example) Next, the present invention will be described in more detail with reference to reference examples, examples, and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified.

Reference example] Copolymer of 95 mol% methyl methacrylate and 1.5 mol% hydroxyethyl methacrylate (molecular weight 20,
000) was dissolved in 400 parts of a mixed solvent of equal amounts of 1.000) and 1.000% methyl ethylkene, and then 10 parts of the above-mentioned polysiloxane compound (5) (molecular weight 3,000)
of the mixture was gradually added dropwise, and the mixture was reacted at 60'C for 5 hours. The product was a homogeneous product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and the acrylic resin reacted. According to analysis, the amount of polysiloxane segments is approximately 7.4%
Met.

Reference Example 2 50 parts of polyvinyl butyral (degree of polymerization: 700, hydroxyl group content: 33 mol%) was dissolved in 500 parts of a mixed solvent of equal amounts of methane and toluene, and then polysiloxane compound (5) (molecular weight: 3,000)1
0 part was gradually added dropwise and the reaction was stirred at 60"C for 5 hours. The product was a homogeneous product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and polyvinyl butyral were separated. According to the analysis, polysiloxane segment l.
The amount was approximately 52%.

Reference Example 3 Polyester (molecule f
fi25,000) 70 parts of methylethylkene and 1
・Dissolve in 700 parts of an equal amount of mixed solvent with toluene, and then dissolve the above-mentioned polysiloxane compound (4) (molecule i110
,000) was gradually added dropwise thereto, and the mixture was reacted at 60''C for 5 hours.

The product was a homogeneous product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and the polyester resin were reacted. Analysis showed that the amount of polysiloxane segments was approximately 5.4%.

19 2 0 Reference Example 4 80 parts of a polyurethane resin (molecular weight 6,000) obtained from polyethylene adipate-1 diol, butane diol and hexamethylene diisocyanate 1 was mixed with methyl edyl ketone and 1 to toluene. It was dissolved in 800 parts of an equal amount of mixed solvent, and then the polysiloxane compound (6) (
10 parts (molecules = 2,000) were gradually added dropwise and reacted at 600C for 5 hours. The product was a homogeneous product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and the polyurethane resin were reacted. According to analysis, the amount of polysiloxane segment 1. was approximately 4.0%.

Reference Example 5 Polysiloxane compound (3) (molecular weight 1,000)
and methacrylic acid chloride at a molar ratio of 5 mol %, methyl methacrylate 45
100 parts of a mixture of 40 mol% of butyl acrylate, 10 mol% of styrene and 3 parts of azobisisobutyronitrile were dissolved in 1,000 parts of a mixed solvent of equal amounts of methyl ethyl ketone and 1.luene, and the mixture was heated at 70°C. Polymerization was carried out for 6 hours to obtain a viscous polymer solution. The product is a homogeneous product,
The polysiloxane compound could not be separated by the fractional precipitation method. Analysis showed that the amount of polysiloxane segments was approximately 6.1%.

Reference Example 6 50 parts of styrene-butadiene copolymer (molecular weight 150,000, butadiene 10 mol%) and 1.
2 parts of Ryl was dissolved in 500 parts of a mixed solvent of equal amounts of methyl ethyl ketone and toluene, and then the above-exemplified polysiloxane compound (7) (molecular iff. 0.000)]. Part O was gradually added dropwise, and the mixture was reacted at 60° C. for 5 hours. The product was a homogeneous product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and the copolymer reacted. Analysis showed that the amount of polysiloxane segments was approximately 6.2%.

Reference Example 7 80 parts of hydroxyethyl cellulose was mixed with 1 part of hydroxyethyl cellulose.
The solution was dissolved in 800 parts of an equimolar mixed solvent of 1.2 and 1.2 ruene, and then 10 parts of the above-exemplified polysiloxane compound (6) (molecular weight 2,000) was gradually added dropwise, and the mixture was reacted at 60°C for 5 hours. . The product was a uniform product, and the polysiloxane compound could not be separated by the fractional precipitation method, and the polysiloxane compound and hydroxyethylcellulose were reacted. Analysis showed that the amount of polysiloxane segments was about 58%.

Reference Example 8 In place of the polysiloxane compound in J3 in Reference Example 1, the above-exemplified fluorocarbon compound (]6) was used, and in the same manner as in Reference Example 1 except for that, a mold release graph 1 cobolimer was obtained.

Reference Example 9 The above-exemplified fluorocarbon compound (18) was used in place of the polysiloxane compound in Reference Example 2, and the rest were as in Reference Example 2.
A releasable graft copolymer was obtained in the same manner as above.

Reference Example 10 A releasable graft copolymer was obtained in the same manner as in Reference Example 5, except that methacrylate l of the above-exemplified fluorocarbon compound (10) was used in place of the polysiloxane compound in Reference Example 5.

Reference Example 11 A releasable graft copolymer was obtained in the same manner as in Reference Example 5 except that laurylaminoacryle-1 was used in place of the polysiloxane compound.

Reference Example 12 Instead of the polysiloxane compound in Reference Example 5, vinyl stearate and methacrylate-1 of the above-mentioned fluorocarbon compound (l4) were used in a molar ratio of 1:1, and the rest were as in Reference Example 5. A releasable graft copolymer was obtained in the same manner.

Examples 1 to] 2 Base material sheet 1: Stitched synthetic paper (Yubo FRG-150.
23 2 4 (thickness: 150 um, made by Oji Yuka Co., Ltd.), and on one side of this, 5.0 g of the coating liquid with the following composition was applied using a bar coater when dry.
/m'' and dried to obtain a thermal transfer image-receiving sheet of the present invention.

Reference example: Graft copolymer 15 0 parts Solvent (butyl acetate/1.Luene/xylene (2/1/2)
85. 0 parts Comparative Example 1 Instead of the Kraf 1 copolymer of Example, 40 parts of a copolymer of 95 mol% methyl methacrylate and 5 mol% hydroxyethyl meccrylate and silicone oil (
A thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in the example except that 0.3 part (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) was used.

Comparative Example 2 Polyvinyl butyral (degree of polymerization 1,700, hydroxyl group content 33 mol%) was used instead of graph I/cobolimer of Example
Using 4.0 parts, {I! In No. 4, a thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in the example.

An ink composition for forming a dye layer having the following composition was prepared, and applied to a 6+Lm thick polyethylene terephthalate film whose back side had been heat-resistant treated using a wire bar so that the dry coating amount was 1,0g/m' and dried. A thermal transfer sheet was obtained.

Disperse dye (Kayaset 1 Blue 714, manufactured by Nippon Kayaku) 4
．． 0 parts polyvinyl butyral resin (S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 4.3 parts Fluorine fatty acid modified silicone wax (X-243525, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts Methyl ethyl ketone/toluene (weight ratio 1/1) 80.0 part isobutanol]. O. Part O: The above thermal transfer image-receiving sheet and the above thermal transfer sheet 1 were superimposed with their respective dye layers and dye-receiving surfaces facing each other, using a heat-sensitive sublimation transfer printer (VY-50, manufactured by Hitachi, Ltd.). Then, recording was performed using a thermal head from the back side of the thermal transfer sheet using a printing energy of 90 mJ/mm'', and the results shown in Table 2 below were obtained.

Mold releasability ○ ○ ○ ○ ○ ○ Mold releasability ○ Print density 0.95 0 99 0 94 0 97 100 0 98 Print density 100 0 99 Mold releasability Print density ○ 0.95 ○ 0 99 ○ 0 94 ○ 0.97 ○ 1.00 ○ 0 76 Xun Lun Distillery Adhesion to base material: Sellotape peeling test ○: No peeling ×・50% or more peeling Release property: Manual peeling after printing ○: Easily peeled off, no problem 2 7 2 8 ×: Difficult to peel off and part of the dye layer was transferred as is.

Inspection of the printed part with a microscope for white spots on printed matter ○: No spots △: Partial white spots ×: 10% or more White spots Print density: Relative optical density base material when Comparative Example 1 is taken as 1.00 Discoloration: Visual observation of non-printed area after being left at 80°C and 90%RH for 2 hours ○: No change △. Slight yellow discoloration Storage stability of printed matter: Visual observation of printed area after being left at 40'C, 90% RH for 48 hours ○: No change △: Slightly dull discoloration

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the Graph 1 Cobolima used in the present invention, and FIG. 2 is a schematic diagram of the dye-receiving layer. Figure 1 Figure 2 Release segment rich layer

Claims (2)

[Claims] (1) In a thermal transfer image-receiving sheet in which a dye-receiving layer is provided on the surface of a base sheet, the dye-receiving layer has at least one segment selected from polysiloxane segments, fluorocarbon segments, and long-chain alkyl segments graft-bonded to the main chain. An image-receiving thermal transfer sheet comprising a graft copolymer having a type of releasable segment. (2) The thermal transfer image-receiving sheet according to claim 1, wherein the main chain of the binder resin is an acrylic, vinyl, polyester, polyurethane, polyamide, or cellulose resin.