JPH0260791A - Image receiving sheet for thermal transfer recording - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to an image-receiving sheet for thermal transfer recording, and in particular to improvement of an image-receiving sheet for thermal transfer recording using heat-sublimable dyes, and improves recording sensitivity and recording image quality. The present invention also provides an image-receiving sheet with significantly improved light resistance.

``Prior art'' The thermal recording method, which allows a recorded image to be obtained simultaneously with a human input signal, is relatively simple, inexpensive, and low-noise equipment, so it is used in a wide variety of applications, such as facsimile-1 computer terminal printers and measuring equipment printers. It is used for.

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 during storage, and the storage stability of recorded images is also poor, causing discoloration due to contact with organic solvents and chemicals. I wake up.

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 not only the color density of the recorded image is low, but also the color fades significantly over time. Therefore,
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 can be improved to a certain extent, but especially when the support is plain paper, it may not be uniform. An image-receiving layer could not be obtained, and both recording sensitivity and image quality were inadequate. Therefore, JP-A-60
As described in Japanese Patent Application Laid-Open No. 61-144394, an intermediate layer such as a thermoplastic resin is interposed between the support and the image-receiving layer, and the coloring material of the coloring material transfer sheet is used during printing. There are methods to improve both recording sensitivity and image quality by improving the adhesion between the layer and the image-receiving layer of the image-receiving sheet to prevent air gaps from occurring.

The lower the softening point of such a thermoplastic resin, the better the adhesion between the coloring material layer and the image-receiving layer, but when the intermediate layer is coated, blocking is likely to occur during winding, which poses a major problem in productivity. So, inorganic! There are methods to make blocking of the intermediate layer less likely to occur by adding additives, organic pigments, or resins with high softening points, but these methods have the disadvantage that recording sensitivity and image quality decrease depending on the amount of these materials added. there were.

Furthermore, when a thermoplastic resin such as styrene-butadiene rubber, polyurethane, polybutadiene, or ethylene-vinyl acetate copolymer is used for the intermediate layer, there are drawbacks such as poor light resistance and yellowing of the intermediate layer.

In view of the current situation, the inventors of the present invention have conducted extensive research into improving image-receiving sheets for thermal transfer recording, which are useful in recording systems that thermally transfer colored coloring materials, particularly heat-sublimable dyes, and have developed an intermediate layer consisting of a specific composition. By forming with paint,
The recording sensitivity is extremely high, providing extremely high-quality recorded images with excellent resolution, clarity, color density, dot removal, etc.
Furthermore, an image-receiving sheet with excellent weather resistance, particularly light resistance, and excellent productivity has been completed.

"Means for Solving the Problem" The present invention provides a thermal transfer recording image-receiving sheet in which an image-receiving layer for receiving a transferred image from a color material transfer sheet is provided on a support. This is a thermal transfer recording sheet characterized in that an intermediate layer containing a silicone-modified acrylic resin as a main component is provided between the sheets.

"Function" In the image-receiving sheet of the present invention, the silicone-modified acrylic resin, which is the main component of the intermediate layer, is a silicone-modified acrylic resin for the purpose of further improving the durability of the acrylic resin. As for its production method, an acrylic resin having a hydroxyl group is prepared, and then heated at about 120° C., for example, according to the following general formula (1) % formula % (where Me is a methyl group, and R and R1 are organic groups).

) There is a method of reacting a silicone intermediate represented by using a catalyst such as tetraisopropyl titanate.

The resulting silicone-modified acrylic resin combines the excellent light resistance, water resistance, and heat resistance properties of silicone with the excellent weather resistance, processability, and corrosion resistance of acrylic resin. This resin has excellent effects that cannot be obtained simply by cold blending silicone and acrylic resin.

The above-mentioned silicone-modified acrylic resin is coated and dried on a support using a solvent system or an emulsion system, but an emulsion system is preferable from the viewpoint of productivity.

The intermediate layer may be composed of a silicone-modified acrylic resin alone, but may also contain calcium carbonate, talc, kaolin, titanium oxide, aluminum hydroxide, zinc oxide, urea/formaldehyde resin particles, polyolefin resin particles, etc., if necessary. Various auxiliary agents such as inorganic or organic pigments, crosslinking agents, brighteners, surfactants, etc. may be added. Among them, polyolefin resin fine particles have a low softening point and are flexible, so that when used in combination with a silicon-modified acrylic resin, both recording sensitivity and image quality can be significantly improved. The proportion of the polyolefin resin fine particles is 5 parts by weight per 100 parts by weight of silicone-modified acrylic resin.
It is preferable to use it in a range of about 500 parts by weight.

The thickness of the intermediate layer is 1 μm or more, more preferably 3 μm or more.
An intermediate layer having a thickness of about 30 μm is desirable.

If the intermediate layer thus formed is subjected to a smoothing treatment before or after forming the image-receiving layer, the recording sensitivity and image quality of the resulting image-receiving sheet can be further improved. The smoothing treatment is appropriately performed by heating and pressurizing treatment using, for example, a super calender.

In the image-receiving sheet of the present invention, the image-receiving layer provided on the intermediate layer is not particularly limited, but a thermoplastic resin layer having an effective dyeing ability with general sublimable dyes is preferably used. Examples of the thermoplastic resin include polymers of vinyl monomers such as styrene, vinyltoluene, acrylic esters, methacrylic esters, acrylonitrile, vinyl chloride, and vinyl acetate; polyesters, polyamides, polycarbonates, Examples include condensation polymers such as polysulfone, epoxy resin, and polyurethane; and cellulose resins.

These thermoplastic resins may be used alone, or two or more resins having different properties may be used in combination. In addition, methylcellulose, ethylcellulose, hydroxypropylcellulose, starch, polyvinyl alcohol, polyamide resin, phenolic resin, melamine resin,
Other resin materials such as urea resin, urethane resin, epoxy resin, silicone resin, and fluorocarbon resin may be contained, and reactive compounds such as polyvalent isocyanate compounds, epoxy compounds, and metal compounds are added to form the image receiving layer. It is also possible to modify. However, it is necessary to keep the thermoplastic synthetic resin constituting the image-receiving layer within a range in which it does not lose its thermoplasticity.

Furthermore, the image-receiving layer contains inorganic and organic materials such as heavy and light calcium carbonate, talc, clay natural 2 synthetic silicates, titanium oxide, aluminum hydroxide, zinc oxide, urea-formaldehyde resin powder, etc., for the purpose of improving writing properties. Various auxiliary agents such as pigments, ultraviolet absorbers, antioxidants, antistatic agents, mold release agents, and lubricants can also be added.

The amount of the components forming the image-receiving layer to be applied onto the intermediate layer is appropriately selected depending on the intended use of the image-receiving sheet, but is generally applied in an amount of about 2 to 15 g/rrr in terms of dry weight. Note that plain paper, synthetic paper, synthetic resin film, etc. can be appropriately selected and used as the support, and it is particularly preferable to use plain paper, which has excellent thermal properties. In addition, the plain paper referred to here includes, for example, paper obtained by ordinary paper making with cellulose pulp as the main component and addition of paper strength enhancers, sizing agents, fixing agents, inorganic and organic fillers, etc. This includes paper that has improved surface properties by size-pressing oxidized starch, etc., or by providing a pre-coat layer mainly composed of pigments such as clay. Paper with excellent properties is particularly preferably used.

In addition, on the image-receiving layer, for example, Japanese Patent Laid-Open No. 59-16568
As disclosed in Japanese Patent Publication No. 8 and Japanese Patent Application Laid-Open No. 61-27290, a thin heat-resistant peeling layer mainly composed of a silicone resin or the like that has the property of transmitting sublimation dyes is formed, It is also possible to prevent the dye or dye layer from being directly transferred from the color material transfer sheet.

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 a heat sublimable dye is used as a coloring material transfer sheet.

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 to a temperature of ao"c or more, such as disperse dyes such as azo, nitro, anthraquinone, and quinoline dyes. , basic dyes typified by triphenylmethane-based dyes, 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 Silicone modified acrylic resin (product name: Siren ARJ
-12L, solid content concentration 44% 2 Nippon Pure Chemical Industries (manufactured by Ife)
To 100 parts, polyolefin resin (trade name: Chemipearl W-300. Solid content concentration 40%, manufactured by Mitsui Petrochemical ■) 1
10 parts were mixed and water was added to prepare an intermediate layer paint having a solid content concentration of 40%.

An intermediate layer was formed by coating on commercially available double-sided art paper (105 g/m2) to a dry weight of 15 g/nf and drying.

Next, 40 parts of methyl ethyl ketone, 40 parts of toluene,
20 parts of cyclohexanone and polyester resin (product name:
Byron 200. Toyobo Co., Ltd.) was dissolved in 20 parts of amino-modified silicone oil (product name: KF-393,
(manufactured by Shin-Etsu Chemical) 0.3 parts, epoxy modified silicone oil (trade name: X-33-343, manufactured by Shin-Etsu Chemical ■) 0.
3 parts were added to prepare a paint for an image-receiving layer. Next, an image-receiving layer coating material was applied onto the intermediate layer to a dry weight of 4 g/rrr, dried at 120° C. for 5 minutes, and cured by heating.

Next, smoothing treatment is performed using a super calender consisting of mirror-finished metal rolls and elastic rolls (linear pressure 200 kg/
cm) to obtain an image-receiving sheet for thermal transfer recording.

Example 2 A silicone-modified acrylic resin (trade name: Siren ARJ-12L, solid content concentration 44%5) was used as a coating liquid for the intermediate layer.
An image-receiving sheet was obtained in the same manner as in Example 1 except that only Nippon Pure Chemical Industries, Ltd.) was used.

Example 3 An image-receiving sheet was prepared in the same manner as in Example 1, except that only a silicone-modified acrylic resin (trade name: Siren ARJ-3A, solid content concentration 44%, manufactured by Nippon Pure Chemical Industries, Ltd.) was used as the coating liquid for the intermediate layer. I got it.

Comparative Example 1 An image-receiving sheet was prepared in the same manner as in Example 1, except that only styrene-butadiene rubber (trade name: JSR-0530, solid content concentration 50%, manufactured by Japan Synthetic Rubber ■) was used as the coating liquid for the intermediate layer. Obtained.

Comparative Example 2 As a coating liquid for the intermediate layer, 100 parts of styrene-butadiene rubber (trade name: JSR-0530, solid content concentration 50% 2 manufactured by Japan Synthetic Rubber Co., Ltd.) and starch (trade name: Ace E) were used.

An image-receiving sheet was obtained in the same manner as in Example 1, except that a mixed solution having a solid content concentration of 20% and 25 parts of Tamago Corn Starch Co., Ltd. was used.

Comparative Example 3 As a coating liquid for the intermediate layer, 100 parts of styrene-butadiene rubber (trade name: JSR-0530, solid content concentration 50% 1 manufactured by Japan Synthetic Rubber) and heavy calcium carbonate (trade name: Softon 1500. @ Kita) were used. An image-receiving sheet was obtained in the same manner as in Example 1, except that 50 parts of the dispersion liquid (manufactured by Powder 1) was used.

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

That is, blue heat sublimable dye (trade name: KST-8-71
4. Dissolve 0.45 parts of Nippon Kayaku ■ and 0.4 parts of polyvinyl butyral resin (trade name: BX-1, manufactured by Block Chemical Industry ■) in 4.6 parts of methyl ethyl ketone and 4.6 parts of toluene to obtain color. The ink for the material layer was applied to a 6 μm thick polyethylene terephthalate film whose back surface was heat-resistant treated to a dry weight of 1.0 g, and dried to prepare a color material transfer sheet.

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 blocking phenomenon, recording sensitivity, image quality, and light resistance were evaluated as follows, and the results are listed in Table 1.

〔Evaluation methods〕

(Blocking phenomenon) Judgment was made based on the presence or absence of blocking during winding during application of the intermediate layer.

(Recording sensitivity) Recorded images were measured with a Macbeth densitometer, and recording sensitivity was evaluated from a sensitivity curve.

(image quality) The recorded images were observed and evaluated using a 25x magnification looper.

(Lightfastness) The degree of discoloration of the image-receiving sheet was evaluated by exposing the image-receiving sheet to direct sunlight for 10 days.

(Evaluation criteria) ○・・・・・・・・・・・・・・・△・・・・・・・・・
・・・・・・・・・X Excellent・・・・・・・・・・・・
...... Inferior "Effect" As is clear from the results in Table 1, the image-receiving sheet for thermal transfer recording obtained in the Examples of the present invention has excellent recording suitability and recording properties. It had image properties.

Claims (2)

[Claims] (1) In an image-receiving sheet for thermal transfer recording in which an image-receiving layer for receiving a transferred image from a color material transfer sheet is provided on a support, a silicone-modified acrylic resin is mainly used between the image-receiving layer of the image-receiving sheet and the support. An image-receiving sheet for thermal transfer recording, characterized by having an intermediate layer as a component. (2) The image-receiving sheet for thermal transfer recording according to claim (1), wherein the intermediate layer is made of a silicone-modified acrylic resin containing a polyolefin resin.