JPH045076A - Preparation of transfer sheet - Google Patents

Abstract

PURPOSE:To carry out printing at high speed using a highly volatile solvent by preventing the charging of an ink layer by forming the conductive ink layer printed on transfer pasteboard so as to have patterns connected at least partially each other. CONSTITUTION:Patterns are printed on transfer pasteboard made of heat- resistant plastic using conductive ink. The patterns pref. consist of ink layers 2 having patterns being a size larger than electrode patterns and the ink layers 3 bridging the ink layers 2. After a solvent is evaporated, adhesive layers 4 having the patterns smaller than those of the conductive ink layers 2 but same to the electrode patterns are printed on the conductive ink layers 2 to obtain a transfer sheet imparting the conductive ink layers having desired patterns. As the transfer pasteboard, a polyester sheet is pref. and, especially, a biaxially stretched polyethylene terephthalate sheet almost generating no expansion and contraction due to heat is optimum. Conductive ink to be used is prepared, for example, by dispersing a conductive filler having a particle size of about 1-10mum in vihicle composed of a vinyl type resin.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing a transfer sheet used for manufacturing an electrode sheet.

[Conventional technology]

Electrostatic precipitator air purifiers use corrugated electrodes, which are made by stacking sheet-shaped electrodes at predetermined intervals, with thin electrodes made of conductive material placed on a sheet of insulating material. ing. Regarding the manufacturing technology of electrode sheets constituting corrugated electrodes, the applicant has previously proposed a method using transfer technology and a transfer sheet used for manufacturing (
Patent Application No. 21404). Transfer sheets used to manufacture electrode sheets, including the above-mentioned manufacturing techniques, have conventionally been prepared by providing a conductive ink pattern with the same pattern as the electrode pattern by screen printing or by overprinting by gravure printing. It has gained. Screen printing requires a relatively large amount of ink, so
Although it is possible to form an electrode pattern with a desired thickness by printing at a certain degree, productivity is low because it takes time to dry the solvent. Also,
Solvent tends to remain in the ink layer, and the specific resistance of the conductive ink layer is unexpectedly high. On the other hand, gravure printing has a fast printing speed and solvent volatilization takes a short time, but because the amount of ink that can be applied in one printing is small, overprinting is required to obtain an ink layer with the desired conductivity. There must be. When overprinting conductive ink at high speed using a highly volatile solvent, static electricity is generated and the previously printed ink pattern is charged, and when rough printing is repeated on top of it, discharge occurs and the ink evaporates. There is a risk of ignition of the solvent. For this reason, high-speed printing, which is an advantage of the gravure printing method, cannot be utilized.

[Problem to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems when producing a transfer sheet for producing an electrode sheet by the gravure overprinting method, and to provide a production method that enables high-speed printing.

[Means to solve the problem]

The method for producing a transfer sheet of the present invention involves gravure overprinting using conductive ink on a transfer mount made of heat-resistant plastic, so that individual ink patterns that become electrodes are interconnected at least in part with adjacent ink patterns. The pattern is printed, the solvent is completely removed from the ink layer by heating, and then an adhesive layer is printed in the same pattern as the electrode pattern on the conductive ink pattern. In the extreme, the conductive ink layer pattern may be a pattern that is printed solidly on the entire surface of the transfer mount, but from an economical point of view, as shown in Figure 1, the pattern of the conductive ink layer is printed on the transfer mount (1) rather than the electrode pattern. Ink layer with a slightly larger pattern (2
) and an ink layer (3) that bridges them. After the solvent dries, as shown in Figures 1 and 2, if an adhesive layer (4) with the same pattern as the electrode pattern is printed on the conductive ink layer (2), the desired pattern can be obtained. A transfer sheet is obtained which provides a patterned conductive ink layer. A polyester sheet is preferably used as the transfer mount. In particular, a biaxially oriented polyethylene terephthalate sheet is most suitable because it hardly expands or contracts due to heat. There is no particular limit to the thickness of the transfer mount, but for ease of handling,
It is preferable to select from the range of 2 to 38 μm. If necessary,
Similar to conventional transfer mounts, a material coated with a thermosetting resin such as melamine resin, epoxy resin, or urethane resin and cured by heating is used to provide a release agent layer. The conductive ink used includes, for example, a vinyl resin vehicle and a conductive filler having a particle size of about 1 to 10 μm dispersed therein. Known conductive fillers may be used, such as carbon powders such as Ketschenblack and graphite powder, and metal powders such as silver, copper, and nickel. Examples of vinyl resins used as the vehicle are vinyl chloride-vinyl acetate copolymer, vinyl chloride-acetate vinyl alcohol copolymer, and vinyl chloride-acetate-maleic acid copolymer. The choice of ink solvent depends on the vehicle. It is preferable to use something that evaporates as easily as possible. The heat drying performed after printing the conductive ink layer is generally preferably performed at a temperature of 120'C or higher, although this will vary depending on the volatility of the solvent used. It goes without saying that the upper limit of the heating temperature is the heat resistant temperature of the transfer mount. Adhesives are selected from known types such as acrylic, chlorinated polyolefin, rubber, urethane, and epoxy, depending on their adhesion to the vehicle for the conductive ink layer and the transfer material (typically a polypropylene sheet). Choose with consideration. In particular, a heat-sensitive type is suitable because it provides a transfer sheet with a conductive ink layer that can be easily cut. Although the printing method for the adhesive layer is arbitrary, the gravure method, which can print at high speed, is preferable. [Function] By making the pattern of the conductive ink layer printed on the transfer mount not a pattern in which each ink pattern is independent, but a pattern in which at least some of the ink patterns are connected to each other, the ink layer can be prevented from being charged. This is because the printed conductive ink layer is electrically integral, always in contact with a metal printing roll or the like at some point, and is grounded with a sufficiently low ground resistance. If there is no charge, there is no need to worry about sparks generated by discharge during overprinting and igniting the volatilized solvent.
It is possible to print at high speed using highly volatile solvents. [Example 1] A conductive ink having the following composition was prepared. Conductive filler (graphite powder > 40 parts by weight Vehicle 20 parts by weight (chlorine, vinegar, vinyl alcohol copolymer) Solvent
40 parts by weight (methyl ethyl ketone: toluene - 1 = 1) A melamine resin-based mold release agent was applied onto a 25 μm thick polyethylene terephthalate film "Lumirror 510J (manufactured by Toshi), and cured by heating to obtain a transfer mount. On the release layer of the transfer mount, a gravure plate with a pattern similar to that shown in Figure 1 (100 lines per inch, plate depth 80
μTrL) was used to apply the above conductive ink at 70 m/m.
The ink was overprinted four times at a printing speed of 1.5 in. and heated to a temperature of 120'C for 1 minute to evaporate the solvent to form a conductive ink layer with a thickness of 15 μm. Apply acrylic acid-vinyl chloride-vinyl acetate copolymer adhesive to a thickness of 3.
A transfer sheet was obtained by gravure printing in a pattern according to a desired electrode pattern so that the size was .mu.m. Until now, when printing a conductive ink layer using the gravure method, the printing speed had to be kept at 30 TrL/m or less for safety reasons. The printing speed in the manufacturing method of the present invention far exceeds this. [Effect of the invention 1] According to the manufacturing method of the present invention, the conductive ink printing process, which has been rate-limiting in the manufacturing of transfer sheets for corrugated electrode manufacturing, can be eliminated.
It can be carried out in a shortened time. The improved productivity compared to conventional methods will help reduce the cost of transfer sheets and shorten delivery times.

[Brief explanation of drawings]

1 and 2 are views showing an example of a transfer sheet obtained by the manufacturing method of the present invention, in which FIG. 1 is a plan view, and FIG. 2 is a cross section taken in the knee I direction of FIG. 1. It is a diagram. 1...Transfer mount 2.3...Conductive ink layer 4...Adhesive layer Patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Souo Suga Figure 1 Figure 2

Claims (2)

[Claims] (1) On a heat-resistant plastic transfer mount, print a pattern in which individual ink patterns that become electrodes are interconnected at least in part with adjacent ink patterns by gravure overprinting using conductive ink, and then heat it. After completely removing the solvent from the ink layer, a method for manufacturing a transfer sheet comprises printing and providing an adhesive layer in the same pattern as the electrode pattern on the conductive ink pattern. (2) The manufacturing method according to claim 1, wherein the pattern of the adhesive layer is printed smaller than the pattern of the conductive ink layer.