JPH01228891A - Heat transfer recording image receiving sheet - Google Patents

Abstract

PURPOSE:To provide excellent recording sensitivity and to improve recorded image shelf stability by constituting an image receiving layer of aqueous coating solution containing dyeing resin, aqueous modified silicone oil and aqueous crosslinking agent to react with one of them. CONSTITUTION:Aqueous dyeing resin uses, for example, polyester, polystyrene, polyurethane, vinyl acetate copolymer, acrylic copolymer, epoxy resin, acetate resin, nylon resin, etc., and aqueous modified silicone oil uses, for example, alcohol modified silicone oil, or epoxy polyether modified silicone oil. Further, aqueous crosslinking agent uses, for example, aminoplast resin, melamine resin, epoxy resin, aziridine resin, isocyanate resin, etc. The aqueous crosslinking agent is contained 0.5-10wt.% to the aqueous dyeing resin, and added to image receiving layer forming coating solution. The coating amount of the solution on a support is approx. 4-15g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an image receiving sheet for thermal transfer recording, and in particular to an improvement of an image receiving sheet for thermal transfer recording using a heat sublimable dye, which has excellent recording sensitivity, Moreover, the present invention provides an image-receiving sheet in which the storage stability of recorded images is significantly improved.

``Prior art'' The thermal recording method, which allows a recorded image to be obtained at the same time as the input signal, uses a relatively hour wheel, is inexpensive, and has low noise. It is used in various directions.

The most commonly used recording medium for these thermal recording systems is so-called color-forming type thermal recording paper, which is provided with a recording layer that develops color by causing a physical or chemical change when heated. However, color-forming type thermal recording paper tends to develop unnecessary color during the manufacturing process and storage, and the storage stability of recorded images is also poor, and the color fades due to contact with organic solvents and chemicals. It causes a phenomenon.

Therefore, a recording method using a recording medium that utilizes colored coloring material itself has been proposed as a recording medium to replace color-forming type thermal recording paper.
In the publication, a coloring material that is solid or semi-solid at room temperature is coated on a support such as paper or a polymer film, and the coloring material on the support is brought into contact with recording paper, and then a thermal recording head is applied to the coloring material. A method has been proposed in which a recorded image is obtained by heating a coloring material on a support and selectively transferring the coloring material to a recording paper.

In this recording method, the coloring material on the support is melted, evaporated, and sublimated by heat, and then transferred to the recording paper, and a recorded image is obtained by adhesion, adsorption, and dyeing.The feature is that plain paper can be used as the recording paper. It is said that there is. In particular, recording methods using sublimable dyes as coloring materials produce images with excellent tonality, and therefore attempts are being made to apply them to full-color recording applications.

However, when plain paper is used as the recording paper, dyeing is particularly difficult to occur, and the color density of the recorded image is not only low (but also causes significant fading over time).
JP-A-57-107885, JP-A-59-165
As described in Japanese Patent No. 688, US Pat. No. 3,601,484, and the like, an image receiving sheet having an image receiving layer mainly composed of a thermoplastic resin is used.

``Problems to be solved by the invention'' By forming an image-receiving layer mainly composed of thermoplastic resin, recording sensitivity and storage stability are improved to some extent, but it is not always sufficient, and the recorded image fades when exposed to light. Problems such as unnecessary heat fusion between the image-receiving sheet and the color material transfer layer, and bleeding of dye within the image-receiving layer during long-term storage occur. In particular, if the image-receiving layer is composed of an aqueous coating liquid containing a water-soluble or water-dispersible thermoplastic resin as its main component, the water-soluble resin, emulsifier, dispersant, etc. During storage, the dye bleeds within the image-receiving layer, resulting in a significant drop in resolution.

In view of the current situation, the present inventors have conducted extensive research into improving image-receiving sheets for thermal transfer recording that are useful for recording methods that thermally transfer colored coloring materials, particularly heat-sublimable dyes. By forming the film with an aqueous coating liquid consisting of the following, not only can recording images with excellent recording sensitivity and extremely clearness and high color density be obtained, but unnecessary thermal fusion between the image receiving sheet and the color material transfer layer does not occur. In addition, we have completed an image-receiving sheet that exhibits excellent storage properties after recording.

[Means for Solving the Problems] The present invention provides an image-receiving sheet for thermal transfer recording comprising an image-receiving layer on a support that receives a transferred image from a colorant transfer sheet, in which the image-receiving layer is dyed in an aqueous medium. This is an image-receiving sheet for thermal transfer recording, characterized in that it is formed by coating and drying an aqueous coating liquid containing an adhesive resin, an aqueous modified silicone oil, and an aqueous crosslinking agent that reacts with at least one of these.

"Function" In the image-receiving sheet of the present invention, the water-based dyeable resin, which is the main component constituting the image-receiving layer, is a water-soluble or water-dispersible thermoplastic resin, such as polyester, polystyrene, polyurethane, vinyl acetate-based resin, etc. Examples include copolymers, acrylic copolymers, epoxy resins, acetate resins, and nylon resins.

Specific examples of such water-based dyeable resins include, for example, the product name Pluscoat Z series manufactured by Gooi Kagaku ■, and the product name Polyester-kl? manufactured by Nippon Gosei Kagaku ■. series, product name Pyronal series manufactured by Toyobo, product name Hytran AP series, Hytran IIW series, Finetex ES manufactured by Dainippon Ink Chemical Aren.
series, PES Resin series made by Takamatsu Oil ■, Eastman WNT-3 made by Eastman Kodak Company.
Examples include IZE, and resins having a Tε of 40 to 130''C1, more preferably 60 to 110C, are particularly preferably used.

The aqueous modified silicone oil used in the present invention means a modified silicone oil that is water-soluble or water-dispersible and has a reactive functional group, such as alcohol-modified silicone oil, epoxy polyether-modified silicone oil, etc. can be mentioned.

The specific implementation of such aqueous modified silicone oil is as follows:
For example, the product name is SF-842, which is made of silicone 0 grade.
7, SF-8421, etc. In addition, these water-based modified silicone oils have a ratio of 0.5 to the water-based dyeing resin.
It is used in a range of about 10 to 4% by weight, preferably about 1 to 6% by weight.

The water-based crosslinking agent that can react with at least one of the water-based dyeing resin and the water-based modified silicone oil is a water-soluble or water-dispersible crosslinking agent, such as aminoplast resin, melamine resin, epoxy resin, aziridine resin, and isocyanate resin. etc.

These aqueous crosslinking agents have a ratio of 0.5 to
It is added to the coating liquid for forming the image-receiving layer in an amount of about 10% by weight, preferably 1 to 5% by weight, and reacted by heat action in the drying process of the coating liquid or in the post-treatment process. Of course, a catalyst that promotes the crosslinking reaction may be used in combination.

The aqueous coating liquid that forms the image-receiving layer contains, for example, heavy calcium carbonate, light calcium carbonate, talc, clay, natural silicates, synthetic silicates, and titanium oxide for the purpose of improving writability. For the purpose of adding inorganic or organic pigments such as aluminum hydroxide, zinc oxide, urea formaldehyde resin powder, modifying the image-receiving layer, or imparting other functions.
For example, various auxiliary agents such as ultraviolet absorbers, antioxidants, antistatic agents, mold release agents, and lubrication agents can also be added. It is also possible to use other synthetic resins in combination without impairing the characteristics of the present invention.

The amount of the image-receiving layer forming coating liquid applied to the support is adjusted appropriately depending on the purpose of use of the image-receiving sheet.
It is applied in a range of approximately g/m.

As the support, for example, plain paper, synthetic paper, synthetic resin film, etc. can be appropriately selected and used, but plain paper is preferably used because it has excellent thermal properties.

Note that plain paper here refers to, for example, paper that is made by ordinary paper making by adding cellulose bulb as a main component and adding paper strength agents, sizing agents, fixing agents, inorganic or organic fillers, etc. This includes paper that has improved surface properties by size-pressing starch, etc., or by providing a pre-coat layer mainly composed of pigments such as clay. Paper with excellent properties is particularly preferably used. Also preferably used is paper that is provided with a rubber elastic layer made of synthetic rubber latex or the like, a foaming agent, a microporous layer made of hollow capsules, etc. to improve adhesion and thermal transfer efficiency.

The image-receiving sheet for thermal transfer recording of the present invention thus obtained is:
In particular, it exhibits extremely excellent performance as an image-receiving sheet when a sheet containing heat-sublimable dye is used as a color material transfer sheet, and it has excellent recording sensitivity and can produce recorded images that are extremely clear and have high color density. It not only provides excellent storage stability for recorded images, but also exhibits excellent properties in terms of preservation of recorded images.

The heat sublimable dye referred to in the present invention does not cause colorant transfer even when it comes into contact with an image receiving sheet under normal handling conditions;
For example, it refers to dyes that undergo colorant transition by melting, evaporation, sublimation, etc. only when heated above 60°C, such as disperse dyes such as azo, nitro, anthraquinone, and quinoline dyes, and triphenyl dyes. The dye is appropriately selected from among various dyes such as basic dyes typified by methane-based dyes and fluoran-based dyes, and oil-soluble dyes.

In addition, the image receiving sheet for thermal transfer recording of the present invention can be used not only by a thermal recording method in which contact heating is performed using a hot plate or a thermal head of a thermal printing unit, but also by heat radiation such as an infrared lamp, a YAG laser, a carbon dioxide laser, etc. It is also useful for thermal recording using a non-contact heating method.

"Examples" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these Examples. Further, unless otherwise specified, parts and % in the examples represent "parts by weight" and "% by weight", respectively.

Example 1 Polyurethane emulsion (product name: Hydran AP
40. 100 parts of alcohol-denatured silicone oil (product name: sF-8427, manufactured by Dainippon Ink ■, concentration 22%),
After dissolving 1.1 parts of Toshi Silicone Co., Ltd., melamine resin crosslinking agent (trade name: B[CKAMINE PM-
An aqueous coating solution for forming an image-receiving layer was prepared by adding 1.4 parts of N (manufactured by Dainippon Ink 2, R degree 80%).

Apply this coating liquid to commercially available synthetic paper (product name: COPO FPG 150).
An image receiving sheet for thermal transfer recording was produced by coating and drying the mixture on a film (manufactured by Tamago Yuka Synthetic Gi) to a dry weight of 6 g/M.

Example 2 An image-receiving sheet for thermal transfer recording was prepared in the same manner as in Example 1, except that the following substances were used as an aqueous dyeing resin, an aqueous modified silicone oil, and an aqueous crosslinking agent in the preparation of an aqueous coating solution for forming an image-receiving layer. was manufactured.

- Water-based dyeable resin: Water-based polyester resin (product name: Plasco) Z446. (manufactured by Goyo Kagaku ■)・Water-based modified silicone oil: Alcohol i-based silicone oil (product name: SF 8427. Manufactured by Toshi Silicone ■)・
Water-based crosslinking agent: Melamine resin (product name: Sumitex M-3, manufactured by Sumitex Chemical ■)
Example 3 An image-receiving sheet for thermal transfer recording was prepared in the same manner as in Example 1, except that in preparing the aqueous coating solution for forming the image-receiving layer, the following substances were used as the aqueous dyeing resin, the aqueous modified silicone oil, and the aqueous crosslinking agent. was manufactured.

・Water-based dyeable resin dihydrous polyester resin (Product name: Pyronal MD 1200. Manufactured by Toyobo ■) ・Aqueous denatured silicone oil: Alcohol-denatured silicone oil (Product name: SF 8427. Manufactured by Toyobo Silicone ■)・
Aqueous crosslinking agent: Melamine resin (trade name: BECKAMINE PM-N, manufactured by Dainippon Ink) Example 4 In the preparation of an aqueous coating solution for forming an image-receiving layer, as an aqueous dyeable resin, an aqueous modified silicone oil, and an aqueous crosslinking agent. Image receiving sheets for thermal transfer recording were produced in the same manner as in Example 1 except that the following materials were used.

・Water-based dyeable resin: Water-based polyurethane resin (product name: Hydran AP40, manufactured by Dainippon Ink) ・Water-based modified silicone oil: Epoxy ether modified silicone oil (product name: SF 842L, manufactured by Toray Silicone 0)
Aqueous crosslinking agent: Isocyanate resin (Product name: Elastron A-38. Daiichi Kogyo Seiyaku Gll
Comparative Example 1 Example 1 except that the aqueous modified silicone oil and the aqueous crosslinking agent were not added in the preparation of the aqueous coating solution for forming the image-receiving layer.
An image receiving sheet for thermal transfer recording was produced in the same manner as above.

Comparative Example 2 An image-receiving sheet for thermal transfer recording was produced in the same manner as in Example 1, except that no aqueous crosslinking agent was added in the preparation of the aqueous coating solution for forming the image-receiving layer.

Comparative Example 3 An image-receiving sheet for thermal transfer recording was produced in the same manner as in Example 1, except that no aqueous modified silicone oil was added in the preparation of the aqueous coating solution for forming the image-receiving layer.

A quality comparison test was conducted on the seven types of image-receiving sheets for thermal transfer recording thus obtained as follows.

That is, blue heat sublimable dye (Solvent Blue 105) 1
1.5 parts of ethyl cellulose, 10 parts of isopropyl alcohol, and 5 parts of ethanol were mixed, ground and dispersed in a sand mill, and the dye ink had an average particle diameter of 1 μm.
A coloring material transfer sheet was prepared by solid gravure printing on the untreated surface of a μm heat-resistant treated polyester film so that the dry coating amount was 1 g/cd.

Next, the coated surfaces of the color material transfer sheet and the image receiving sheet for thermal transfer recording are overlapped, and heat is applied from the back side of the color material transfer sheet using a thermal head (12 V, 2 to 8 m5ec) to form a thermal transfer recorded image on the image receiving surface of the image receiving sheet. The occurrence of the fusion phenomenon, heat bleed suitability, and printing light resistance were evaluated as follows, and the results are listed in the table.

[Fusion phenomenon]

Evaluation was made based on the degree of fusion phenomenon that occurred when heat was applied using a thermal head.

[Heat bleed suitability]

After processing at 60°C for 48 hours, bleeding of the print was observed and evaluated using a 25x louver.

[Printing light resistance]

Image density maintenance rate after exposure to glass transmitted light for 10 days (
%).

Separately, yellow heat sublimable dye (Disverse Yellow 54)
Dye ink was prepared in the same manner as above using red heat sublimable dye (Disperse Illusod 60), and printed with the above blue dye ink in a random pattern in the order of yellow, red, and blue for full-color recording. A color material transfer sheet was created.

Next, the coated surfaces of the color material transfer sheet and the image receiving sheet for thermal transfer recording are overlapped, and heat is applied from the back side of the color material transfer sheet using a thermal head (12 V, 2 to 8 m5ec). Overprinting was performed in the order of blue, and [full color suitability] was evaluated based on the degree of transfer of unnecessary dye. Further, the density of the obtained black recorded image was measured using a Macbeth densitometer, and the [image density] was evaluated based on the highest recorded density.

In addition, in the image receiving sheets of Comparative Examples 1 and 3, the image receiving sheet and the color material transfer layer were thermally fused during recording, and subsequent quality comparison tests could not be conducted. Also, comparative example 2
A thermal fusion phenomenon also occurred with the image-receiving sheet, and a black recorded image could not be obtained.

The evaluation criteria were as follows.

〔Evaluation criteria〕

○・・・・・・・・・・・・・・・△・・・・・・・・・
・・・・・・・・・×Excellent・・・・・・・・・・・・
...... Inferior Table ``Effect'' As is clear from the results in the table, the image-receiving sheet for thermal transfer recording obtained in the Examples of the present invention has excellent recording suitability and recorded images. It had a characteristic.

Claims (1)

[Claims] In an image-receiving sheet for thermal transfer recording comprising an image-receiving layer for receiving a transferred image from a color material transfer sheet on a support, the image-receiving layer contains a dyeable resin, a water-based modified silicone oil, and at least one of these in an aqueous medium. 1. An image-receiving sheet for thermal transfer recording, characterized in that it is formed by coating and drying an aqueous coating liquid containing an aqueous crosslinking agent that reacts with the aqueous crosslinking agent.