JPH0440196B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a heat-sensitive transfer recording sheet, and particularly to a sheet for an overhead projector (hereinafter abbreviated as OHP) capable of forming color images. [Prior Art] Conventionally, OHP sheets have been used to project handwritten manuscripts or sheets recorded by electrophotography using reflected light in the transmitted light region. Currently, sheets with black characters, figures, and other images copied thereon are used. However, in recent years there has been a growing demand for OHP sheets that can project color images. Methods for producing color images include image forming methods such as in-jet recording, thermal transfer recording, and electrophotography. Among these methods, the thermal transfer recording method using a thermal head has come to be widely used because of its advantages such as low noise, relatively inexpensive and compact equipment, and excellent maintainability. However, used in traditional electrophotographic methods
Since OHP sheets are coated with a resin having a high softening point, they have the disadvantage that ink does not transfer when copied using a thermal transfer copying machine.
Furthermore, when an untreated film is used, it has the drawbacks of poor ink receptivity and poor transportability in a copying machine due to static electricity. [Problems to be Solved by the Invention] In view of the above-mentioned actual situation, the present inventor has studied a coating layer with good ink receptivity in a thermal transfer type copying machine, transportability in a copying machine, and an antistatic effect. , with excellent copyability and transportability on thermal transfer copiers.
We discovered an OHP sheet and arrived at the present invention. [Means for Solving the Problems] The present invention provides a recording medium in which one side of the film is provided with an ink-receiving layer that is melted by heat, and the other side is provided with a layer that contributes to slipperiness and antistatic properties. The present invention is an OHP sheet made by coating a film with a resin composition having a softening point of 50°C to 110°C and an antistatic treatment agent. [Function] The present invention will be explained in detail below with reference to the drawings. First, FIG. 1 shows a schematic cross section, and 1 in the figure is a film. This film is a transparent plastic film such as polyester film, polypropylene film, cellulose film, polyimide film, or polycarbonate film, and is a film that does not undergo deformation due to heat during ink transfer. Next, 2 in the figure is a thermal transfer ink receiving layer. The coating layer used in the present invention is 50°C to 110°C.
This is a coating composition containing a resin that softens at ℃. The resins used include polyethylene, polyvinyl chloride, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl butyral,
Examples include polyacrylic ester, polyamide, polyester, polyvinyl alcohol, and copolymers thereof. Furthermore, plasticizers such as polyethylene glycol and chlorinated paraffin can also be added to these resins. All of them are resins that soften at 50°C to 110°C, and resins with a softening temperature lower than 50°C are undesirable because they cause blocking when stacked in large numbers. Furthermore, resins with a softening temperature of 110° C. or higher have the disadvantage that the softening temperature is higher than the softening temperature of the ink transferred by the thermal head, so the ink is not transferred to the receiving layer and the ink adhesion is poor. As a solvent for dissolving these resins, organic solvents such as alcohols and ketones, and water can be used. Furthermore, a pigment may be added for the purpose of improving the slipperiness between the ink receiving layer and the ink sheet. The amount of pigment added is preferably 10 parts by weight or less per 100 parts by weight of resin, but as long as the haze of the film is 15% or less, there will be no problem with projection on OHP, so more pigments can be added. . Next, 3 in the figure is an antistatic layer. cationic surfactant,
Known water-soluble and organic solvent-soluble antistatic agents such as quaternized salt type acrylic resin can be used, but it is preferable to use an antistatic agent that has good sliding properties with various parts of a thermal transfer copying machine, such as a conveyance roll and a platen roll. Materials with poor slip properties are undesirable because they may cause conveyance jams. Further, the surface electrical resistance value needs to be 1×10 ¹⁵ Ω or less. When the resistance is 10 ¹⁵ Ω or more, static electricity is generated, which tends to attract dust when handling the sheet, which may cause print omission during ink transfer. Furthermore, regarding the coating method of the thermal transfer ink receiving layer and the antistatic layer, the ink receiving layer is coated by a known method (roll coating method, rod bar coating method, spray coating method).
~10g/m ² Practically 2-4g/m ² , for antistatic layer 0.01-3g/m ² Practically 0.05-2
It is recommended to apply the coating at a rate of about g/ ^m2 . After such a coating layer is provided, the coating layer is dried as soon as possible. [Example] Examples are given below to more specifically explain the present invention. All parts shown below are parts by weight. Example 1 1 Thermal transfer ink receiving layer Polyacrylic ester resin (Nippon Acrylic, Primal AC61) 100 parts Silicon dioxide (Fuji Davison, Thyroid
978) 3 parts water 50 parts 2 Antistatic layer cationic surfactant (manufactured by Yoshimura Yuka Kogyo, Elique SEI52) 1 part methanol 100 parts This coating solution 2 (coating solution for forming an antistatic layer) was coated to a thickness of 50 μm. It was coated on the surface of a polyester film (Lumirror, manufactured by Toray Industries, Ltd.) by a bar coating method, so that the thickness after drying was 1 g/m ² .
Next, apply coating liquid 1 (coating liquid for thermal transfer ink receiving layer formation) on the back side in the same way, and after drying, the thickness is 2 g/
^m2 . Comparing the thermal transfer recording sheet thus provided with an untreated polyester film, Table 1
As shown, it exhibited excellent performance in ink receptivity, transportability during copying, and antistatic property. Example 2 1 Thermal transfer ink receiving layer polyvinyl acetate resin (manufactured by Hoechst Synthesis, Movinyl DC) 100 parts methanol 50 parts 2 Antistatic layer cationic acrylic resin (manufactured by Hamano Industries, Hamakote ES150) 1 part methanol 100 parts Example 1 and The coating was applied and dried in the same manner to obtain a thermal transfer recording sheet. Similar to Example 1, excellent performance was shown. [Effects of the Invention] According to the present invention, as shown in Table 1, an OHP recording sheet with excellent ink receptivity and transportability in a thermal transfer copying machine was obtained.

[Table] Evaluation method ◎: Particularly good ○: Good ×:
defective

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the recording sheet of the present invention. In the drawing 1...Film, 2...Ink receiving layer, 3
...Antistatic layer.

Claims (1)

[Claims] 1 A recording sheet with a haze level of 15% or less, which has a thermal transfer ink-receiving layer on one surface of the film and an antistatic layer with slipperiness and antistatic properties on the other surface, and is The thermal transfer ink receiving layer on one surface of the sheet is made of a synthetic resin composition having a softening point of 50° C. to 110° C., and the antistatic layer on the opposite surface has a surface electrical resistance value of 1×10 ¹⁵ Ω or less, A recording sheet characterized by containing a cationic surfactant as an antistatic agent.