JPH052516B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a transparent film for overhead projectors (hereinafter referred to as OHP film), and particularly to a transparent film used for recording with a dot impact printer. (Prior Art) In recent years, characters, figures, etc. printed on a transparent film have been enlarged and projected onto a screen using OHP, and have been increasingly used for meetings, research presentations, etc. This printing method includes handwriting,
Copying a document using an electrostatic copying machine, direct printing using a thermal transfer printer, direct printing using an inkjet printer, and direct printing using a dot impact printer are generally known. Among these, the method of printing directly with a dot impact printer is as follows.
Compared to the method of , it is more efficient because it can be printed directly on a personal computer or word processor, and color printing is also possible. Compared to the method of , it does not require the use of expensive thermal transfer ribbons. This method has advantages such as being economical, being shipped in large numbers, being widely used, and being highly reliable. Required conditions for OHP film for dot impact printers include good fixation of the ink printed from the printer's ink ribbon, resistance to scratches from the printer's print head, and high light transmittance. be able to. On the other hand, ink used in dot impact printers generally contains dyes and pigments in a non-drying solvent and vehicle in order to maintain good printing performance over a long period of time. When such ink is printed on plain paper, there is no problem because the paper has good ink absorption properties, but conventional OHP films do not have ink absorption properties, so ink fixation may be poor or ink transfer may be poor. Practical printing cannot be obtained due to problems such as insufficient density and low density. Furthermore, there is a problem in that scratches occur due to rubbing of the printing head during printing. Therefore, at present, there is no transparent film that satisfies all the necessary characteristics of an OHP film for dot impact printers as described above. <Problems to be Solved by the Invention> The present invention improves the problems of OHP films for dot impact printers as described above, and provides dots with excellent fixability for non-drying inks, scratch resistance, and light transmittance. The present invention provides a transparent film for impact recording. <Means for Solving the Problems> The present invention provides an ink receiving layer on at least one side of a transparent substrate, the main components of which are a pigment with an average particle size of 3 to 100 μm, a pigment with an average particle size of 5 to 50 μm, and an adhesive. This is a transparent film for dot impact recording, characterized in that: Pigments with an average particle diameter of 3 to 100 mμ used in the present invention include organosilica sol, colloidal silica, antimony sol, titanium oxide sol, and the like. By using these very fine pigments, it is possible to improve the ink fixability and prevent a decrease in transparency due to light scattering. Further, among these, organosilica sol and colloidal silica are suitable because they have a large ink penetration and absorption capacity due to their porous properties, and particularly good ink fixing properties. Examples of pigments with an average particle size of 5 to 50 μm used in the present invention include inorganic powders such as silica, calcium carbonate, titanium oxide, diatomaceous earth, talc, calcined clay, and barium sulfate, starch, acrylic, crosslinked polystyrene, Acrylic-styrene copolymer, benzoguanamine resin, urea resin, nylon resin,
Transparent fine resin powders made of epoxy resins, phenol resins, etc. may be used, but the resin powder is not limited to these and may be appropriately selected from those that have good compatibility with the binder described below. By using such a pigment in combination with the aforementioned pigment of 3 to 100 m.mu., it is possible to prevent scratches caused by friction between the print head and the ink receiving layer that may occur during printing. That is, by blending pigments with large particle sizes, large protrusions are formed locally on the surface of the ink-receiving layer, reducing the contact area between the print head and the surface of the ink-receiving layer, and this effect makes it easier for the print head to receive ink. It is possible to prevent the occurrence of scratches on the surface of the layer. In the present invention, the blending ratio of pigments with an average particle size of 3 to 100 μm and pigments with an average particle size of 5 to 50 μm is preferably 100:1 to 100:100 by weight, particularly preferably 100:10 to 100:30. be. Average particle size 3~
If the amount of pigment with an average particle size of 5 to 50 μm is less than 1 per 100 of pigment with a particle size of 100 μm, the effect will hardly be exhibited. Moreover, if it is more than 100, the smoothness of the surface of the ink-receiving layer becomes extremely low, the ink fixability becomes poor, and the transparency also decreases. In addition, the average particle size of the pigment in the present invention is
This refers to the value determined from the specific surface area using the BET method. Examples of the binder used in the present invention include, but are not limited to, acrylic resins, polyester resins, vinyl chloride vinyl acetate copolymer resins, etc., and include transparency, pigment dispersibility, A material with good adhesion to the transparent substrate may be appropriately selected. The blending ratio of the binder and the pigment is preferably 100:100 to 100:400 by weight, particularly preferably 100:250 to 100:350. Transparent substrates used in the present invention include, for example, polyester including polyethylene terephthalate, various acrylic and methacrylic polymers, polyvinyl chloride, polycarbonate, polyimide, cellulose acetate (acetate), regenerated cellulose (cellophane), and celluloid. Examples include, but are not limited to, plastic films such as, but not limited to, those that are transparent, can withstand hitting from the printing head pin during printing with a dot impact printer, and have good adhesion to the ink receiving layer are appropriately selected. do it. The transparent film of the present invention is prepared by applying a coating solution prepared by dissolving or dispersing a material for forming an ink-receiving layer as described above in water or an appropriate solvent on at least one side of a transparent substrate as described above. For example, the ink-receiving layer is provided by coating and drying using a method such as a roll coating method, a blade coating method, a spray coating method, an air knife coating method, a wire bar coating method, a rod bar coating method, or the like. It can be manufactured by. The thickness of the ink-receiving layer is preferably about 5 to 30 μm; if it is less than 5 μm, sufficient ink fixing properties cannot be obtained, and if it is more than 30 μm, a commensurate effect cannot be obtained, causing problems in manufacturing, raw material costs, etc. I end up. The transparent film of the present invention consists of the above-described transparent base material and ink-receiving layer, and various additives may be used in these as necessary. For example, additives such as dispersants, fluorescent dyes, antifoaming agents, lubricants, and resistance agents can be used to improve productivity, printing characteristics, and the like. <Implementation Order> Next, the present invention will be explained according to examples. In addition,
All parts indicating formulations indicate parts by weight. Example 1 A coating liquid having the following composition was applied onto one side of a 100 μm thick polyethylene terephthylate film using a wire bar and dried to form an ink receiving layer 20 μm thick. Organo silica sol (manufactured by Nissan Chemical Industries, Ltd., xylene-butanol silica sol XBA-ST, average particle size 10-20 mμ, solid content 30%) 30 parts (Syroid 404, manufactured by Fuji Davison Chemical Co., Ltd., average particle size 10 μm) Silica 1 part Polyester resin (Manufactured by Toyobo Co., Ltd., Vylon #240, solid content 40%) 10 parts toluene 20 parts methyl ethyl ketone 20 parts cyclohexanone 9 parts Example 2 A coating liquid having the following composition was applied to one side of a 75 μm thick polyethylene terephthalate film using a wire bar. An ink-receiving layer with a thickness of 20 μm was formed by applying and drying the ink-receiving layer. Organo silica sol (manufactured by Nissan Chemical Industries, Ltd., xylene-butanol silica sol XBA-ST, average particle size 10-20 mμ, solid content 30%) 25 parts silica (Mizukasil P-363 manufactured by Mizusawa Chemical Industries, Ltd.,
Average particle size: 7 to 13 μm) 2 parts Vinyl chloride vinyl acetate copolymer resin 4 parts (Sekisui Chemical Co., Ltd., Eslec A) Toluene 20 parts Methyl ethyl ketone 25 parts Cyclohexanone 10 parts Example 3 Using a coating liquid with the following composition In the same manner as in Example 1, an ink receiving layer having a thickness of 20 μm was formed. Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., Snowtech 30, average particle size 10-20 mμ, solid content 30%)
30 parts silica (Thyroid 404, Fuji Davison Chemical Co., Ltd., average particle size 10 μm) 1 part water-based polyester resin (Dainippon Ink Chemical Co., Ltd., Finetex ES-850, solid content 30)
%) 12 parts Water 47 parts Comparative Example 1 An ink-receiving layer with a thickness of 20 μm was formed in the same manner as in Example 1 using a coating liquid having the following composition. Organo silica sol (manufactured by Nissan Chemical Industries, Ltd., xylene-butanol silica sol XBA-ST, average particle size 10-20 mμ, solid content 30%) 30 parts polyester resin (manufactured by Toyobo Co., Ltd., Vylon #240, solid content 40%) 10 parts toluene 20 parts Methyl ethyl ketone 20 parts Cyclohexanone 9 parts Comparative Example 2 An ink receiving layer having a thickness of 20 μm was formed in the same manner as in Example 2 using a coating liquid having the following composition. Silica 1 part (Mizukasil P-363, manufactured by Mizusawa Chemical Co., Ltd., average particle size 7-13 μm) Vinyl chloride vinyl acetate copolymer resin 4 parts (Sekisui Chemical Co., Ltd., Eslec A) Toluene 25 parts Methyl ethyl ketone 30 parts Implementation of the above The transparent films prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were printed using a dot impact printer (PC-PR201V2, manufactured by NEC Corporation), and the ink fixability and scratch resistance were evaluated. These evaluation results are as shown in Table 1, and it was confirmed that the transparent film of the present invention had good optical transparency and exhibited excellent ink fixability and scratch resistance.

[Table] The evaluation method for each item in Table 1 is as follows. (1) Ink fixability: Immediately after printing, the printed area was rubbed with a fingertip, and a good result with no ink coming off was rated as ○, and a good score with ink coming off was rated as ×. (2) Scratch resistance: When printing with a printer at a printing pressure of 2, no scratches were observed on the printing head, and those with scratches were rated ×. <Effects of the Invention> The transparent film for dot impact recording of the present invention has excellent light transmittance and excellent ink fixability and scratch resistance when printed with a dot impact printer. . Therefore, it exhibits particularly excellent characteristics for use in overhead projectors.

Claims (1)

[Claims] 1. At least one side of the transparent base material has an average particle size of 3 to 3.
A transparent film for dot impact recording, characterized in that it is provided with an ink-receiving layer whose main components are a pigment of 100 μm, a pigment with an average particle size of 5 to 50 μm, and a binder. 2 Pigments with an average particle size of 3 to 100 mμ and average particle sizes of 5 to 100 mμ
The blending ratio with 50μm pigment is 100:1 to 100:
100. The transparent film for dot impact recording according to claim 1, wherein the dot impact recording film has a dot impact resistance of 100. 3. The transparent film for dot impact recording according to claim 1, wherein the pigment having an average particle diameter of 3 to 100 mμ is organosilica sol or colloidal silica.