JPH0527555B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a heat-sensitive stencil paper having a stick prevention layer formed of a combination of a phosphate ester type surfactant and polyoxyethylene terephthalate on the surface of a polyester film. For more details,
The present invention relates to thermal stencil paper used in digital plate making using thermal head writing and perforation. [Prior Art] Until now, so-called heat-sensitive stencil paper, in which a thermoplastic synthetic resin film is laminated to a porous support such as porous thin paper or screen mesh through which ink can pass, has been superimposed on an original and irradiated with electromagnetic waves including infrared rays. In the method of perforating a film by punching, it has been proposed to provide a release layer on the surface of the film in order to prevent the perforated film from fusing with the original, making it difficult to remove or damaging the film. ing. However, in the conventional perforation method, the amount of the release layer (overcoat layer) material deposited does not significantly affect the perforability of the film depending on the amount of the overcoat layer deposited. Since the drilling debris caused almost no problems, it was not very important. However, in the film perforation method using thermal head writing, the type of overcoat layer material and the amount of the overcoat layer material greatly affect the perforation performance. For example, if the amount of deposit is too high, the perforability will be reduced and the overcoat material will adhere to and accumulate on the head, resulting in problems that reduce the performance of the thermal head. Therefore, the solution to this problem lies in how to prevent sticking with a small amount of adhesion. As one method, it has been proposed to sandwich paper between the thermal head and the heat-sensitive stencil paper and make holes (Japanese Unexamined Patent Application Publication No. 1989-1999).
103957), but it is impossible to perforate the film using this method with the energy of current thermal heads. Further, even if holes can be formed in terms of heat capacity, heat conduction, and heat diffusion, the resolution will be reduced and the image quality will be poor. Therefore, the present inventor provided a stick prevention layer made of polyoxyethylene-added alkyl phosphate triester and a stick prevention layer made of mono- or disodium and potassium salts of polyoxyethylene-added alkyl phosphate triester on the surface of the polyester film. I suggested that earlier. These phosphate ester type surfactants have a high stick prevention effect even with a very small amount of adhesion, but if a dilute solution of 1% or less is applied to the film surface to reduce the amount of adhesion, repellency will occur on the coated surface and it will not be uniform. There were problems in that a good coating film could not be obtained, the coated surface remained sticky even after drying, and the stick prevention effect decreased over time (about one year) after being coated on the film and drying. [Purpose] The present invention has been made in view of the above problems, and its purpose is to prevent the polyester film from being thermally fused to the thermal head during perforation of thermal stencil paper by thermal head writing, and to prevent the thermal head from being thermally fused. To improve the runnability of base paper during perforation by eliminating secondary problems such as fuzzing, tearing, and peeling of the film caused by blocking and stecking phenomena, and to eliminate film scum during perforation that adheres to the thermal head and The purpose of the anti-stick layer (overcoat layer) is to prevent coating substances from adhering to the thermal head, thereby improving the running properties of the thermal head. [Structure] In order to solve the above-mentioned conventional problems, the present inventors increased the number of carbon atoms in the alkyl group in the polyoxyethylene-added alkyl phosphate ester, increased the number of moles of polyoxyethylene added, or increased both. As a result of studying these methods, we found that although some of the above problems could be solved, they also caused side effects such as decreased solubility in water, repellency on the painted surface, and stickiness of the painted film.As a solution, we decided to use phosphate ester. The present inventors have discovered that mixing polyoxyethylene terephthalate, a water-soluble polymer substance, with a surfactant is effective, leading to the completion of the present invention. Note that polyoxyethylene terephthalate of the formula is an oligomer obtained by polymerizing polyethylene glycol and terephthalic acid. The heat-sensitive stencil paper of the present invention is obtained by laminating a polyester film to a porous support, and further applying a phosphate ester type surfactant represented by the following formula, formula, formula, formula, formula, and formula to the surface of the film. It is characterized by providing a stick prevention layer made of a combination of at least one kind and polyoxyethylene terephthalate represented by the following formula.

【formula】

【formula】

【formula】 【formula】

In each of the above formulas to formulas, R represents an alkyl group or an alkylphenyl group, and the number of carbon atoms in the surfactant is usually in the range of 8 to 24. X represents a hydrogen atom or an alkali metal. In addition, when X is a hydrogen atom, coating is possible although it does not completely dissolve in water. Further, in the formulas to formulas, n is an integer of 1 or more, and a value in the range of 1 to 20 is usually good in solubility and easy to use, but even if it is larger than this, there is no difference in performance. Furthermore, in the formula, m and n each represent an integer of 1 or more. Polyoxyethylene terephthalate used in the present invention The molecular weight may be about 1000 to 10000, preferably about 3000 to 8000, from the viewpoint of water solubility and stick prevention ability, in which case n is 15 to 40 and m is 3 to 6.
It is. In the present invention, the mixing ratio of the phosphate ester type surfactant and polyoxyethylene terephthalate can be varied within a wide range, but in order to achieve the desired purpose, polyoxyethylene It is sufficient to use terephthalate in proportions of 10 to 500 parts, preferably 50 to 200 parts. In addition, the anti-stick layer made of a combination of a phosphate ester type surfactant and polyoxyethylene terephthalate according to the present invention exhibits a high anti-stick effect even with an extremely small amount of adhesion;
0.01-0.5 g/ ^m2 , preferably 0.05-0.3 g/ ^m2 is sufficient. The anti-stick layer can be formed on a polyester film by dissolving and diluting each of the above-mentioned substances in water, coating the solution on the film and drying it. In this case, the concentration of the solution is
The amount is about 0.1 to 5% by weight, preferably about 0.5 to 3% by weight, and the drying conditions may be the usual conditions of about 30 seconds at 70 to 100°C. The polyester film used in the present invention preferably has a thickness of 4μ or less, and porous supports include Japanese paper (tengucho), porous synthetic fiber paper, mixed paper, screen mesh, and various types of woven paper. Cloth, nonwoven fabric, etc. can be used. Further, the porous support and the polyester film can be bonded together with or without using an adhesive (for example, by thermal bonding). [Example] The present invention will be further explained with reference to Examples below, but the present invention is not limited thereto. 2μ thick polyester film and basis weight 12g/
A thermosensitive stencil paper was prepared by laminating ² m2 of Tengucho paper with vinyl acetate-ethylene copolymer (EVA) resin. In addition, the adhesive resin adhesion amount is 2 to 3 g/m ²
The concentration was adjusted so that the coating was applied to a polyester film using a wire bar (0.3 mmφ), and the mixture was laminated using a wet lamination method. Next, an overcoat layer having the contents shown in Table 1 below was coated on the film surface of this heat-sensitive stencil paper and dried to prepare each product A-1 to G-2 shown in Table 1. Furthermore, in this example, the amount of the anti-stick layer deposited is extremely small (1 m ² of base paper).
(0.5 g or less), and in consideration of measurement errors, the amount of adhered anti-stick layer is expressed in Table 1 using the concentration of the coating solution. The diameter of the wire bar used for coating was 0.1 mmφ. Next, using the thermal stencil paper prepared as described above, perforation was performed with a thermal head in copy mode using a thermal recording facsimile receiver RIFAX 5320H (manufactured by Ricoh), and the perforation performance of each sample was evaluated. The results are shown in Table 2 below.

【table】

[Table] In addition, in the surfactants shown in the above-mentioned products of the present invention,

Diester of [formula] mold and

Since it is difficult to completely separate the monoester type of [Formula], samples B-1 and B-2 are

It also contains some [formula], and similarly, the samples of C-1 and C-2 are

Also, the samples of E-1 and E-2 are

Contains [expression]. D-1, D-2, F-1, F-2, G-1, G-
The same holds true for 2, H-1, and H-2.

【table】

〔effect〕

According to the heat-sensitive stencil paper of the present invention constructed as described above, the following advantages can be obtained. (1) In combination with polyoxyethylene terephthalate, the disadvantages of using a phosphate ester type surfactant alone in the overcoat layer were (a) repellency when applying a diluted solution, and (b) after drying. Stickiness of the coating film (d) The film after application does not suffer from the disadvantage that the stick prevention effect decreases over time (about 1 year). (2) By using polyoxyethylene terephthalate in combination with a phosphate ester type surfactant, the stick prevention effect can be achieved with an extremely small amount of coating, so there is almost no chance of the overcoat layer material adhering or depositing on the thermal head. Good perforability. (3) Due to the stick prevention, phenomena such as fuzzing, peeling, and tearing of the film do not occur, and the perforation quality is good, so high-quality images can be obtained. (4) The running performance of the base paper has become smoother and the running performance (during punching) has also been improved. (5) Containing a phosphate ester type surfactant has a strong adsorption force (ion adsorption) on the film surface (because the oil film strength is high), so the amount that sticks and accumulates because the amount that is scraped off by the thermal head is small. There are also very few. (6) Containing a phosphate ester type surfactant has an antistatic effect, so the coated film does not have dirt, dust, or dust attached to it due to static electricity, and the film does not stick, making it easy to process.

Claims (1)

[Scope of Claims] 1. A polyester film is laminated to a porous support, and one of the phosphate ester type surfactants represented by the following formulas, formulas, formulas, formulas, and formulas is applied to the surface of the film. at least 1
A heat-sensitive stencil paper, characterized in that it is provided with a stick prevention layer made of a combination of seeds and polyoxyethylene terephthalate represented by the following formula. [Formula] [Formula] [Formula] [Formula] (However, in each of the above formulas, R represents an alkyl group or an alkylphenyl group, X represents a hydrogen atom or an alkali metal, and m and n each represent an integer of 1 or more).