JP2732575B2 - Base paper for heat-sensitive stencil printing - Google Patents

Description

The present invention relates to a heat-sensitive stencil printing base paper, and more particularly, to a heat-sensitive stencil making method using a heating element such as a thermal head as a heat source, which is excellent in heat sensitivity and does not contaminate the thermal head. The present invention relates to a heat-sensitive stencil sheet which exhibits perforation properties. [Prior art] Heat-sensitive stencil printing paper in which a plastic film is pasted to a porous support with an adhesive and a release agent layer is provided on the surface of the plastic film to prevent fusing with the original has been generally used. I have. As the plastic film used at this time, a polyester film, a vinylidene chloride-vinyl chloride copolymer or the like is used. Further, as the porous support, Japanese paper, thin paper, gauze, cloth-like sheet, non-woven fabric and the like are used. As an adhesive to attach these,
A vinyl acetate adhesive, an acrylic adhesive, a rubber adhesive, and the like are used. The heat-sensitive stencil sheet thus produced is superimposed on a document and irradiated with infrared rays (using an infrared lamp, a flash lamp, etc.) to pierce the sheet (plate making).
The stencil printing is performed using the stencil printing. [Problems to be Solved by the Invention] However, in the method in which the original paper and the original are superimposed and perforated by irradiating an infrared ray or a flash lamp, there is a limitation on the original that can be used because heat generated by light absorption of the original is used. However, a document other than black has a drawback that the reproduction of an image has variations and unevenness and it is difficult to obtain a beautiful printed image. For this reason, in the case of a color image original, it is necessary to temporarily convert the image to a black image by an electronic copying machine, and the toner image copied by the electronic copying machine is melted by heat at the time of perforation and adheres to the base paper. There is. In order to solve such a disadvantage at the time of perforation by infrared irradiation, in recent years, thermal plate making using a heating element such as a thermal head as a heat source has begun to be used. However, in the perforation of a base paper by a thermal head, generally, a thermal head is applied in close contact with the base paper to apply heat, thereby forming a perforated image.Therefore, in a conventional base paper used, a release agent layer is provided on the surface thereof. Despite this, the plastic head is thermally fused to the thermal head and the sticking phenomenon that peels the film from the base paper, and the perforated scum that is the hot melt of the plastic film and adhesive adheres to the thermal head. And the thermal conductivity of the thermal head is hindered. [Means for Solving the Problem] The present inventors have made intensive efforts to solve the above-mentioned drawbacks, and as a result, have disclosed the infrared lamps and flash lamps disclosed in Japanese Patent Application No. 61-23040 filed last time. When a heat-sensitive stencil sheet was manufactured using a urethane-based adhesive compounded with a glycidyl-type epoxy compound that does not have active hydrogen in the urethane prepolymer adhesive used when manufacturing the base paper for perforation, Perforation rate of base paper,
The inventors have found that the fusion of the plastic film to the thermal head and the attachment of perforated scum are greatly improved as compared with the conventional base paper, and that the printing quality is greatly improved, thereby completing the present invention. That is, the present invention relates to a heat-sensitive stencil sheet in which a plastic film is adhered to a porous support, and as an adhesive, (A) a diisocyanate and an average molecular weight such that the equivalent ratio of NCO / OH is 1.5 to 2.0. A urethane prepolymer component using a polyether diol of 400 to 2,000, (B) a glycidyl type epoxy compound having no active hydrogen, and a component containing (A) and (B) as main components,
(A): The plastic film is bonded to the porous support using a urethane-based adhesive composed of (B) = 10: 10 to 10: 1 and having a flow start temperature after curing of 50 to 240 ° C. This is a heat-sensitive stencil printing base paper characterized in that: The diisocyanate used in the present invention is a known aliphatic, alicyclic or aromatic organic diisocyanate having two isocyanate groups in a molecule. Examples of particularly preferably used are hexamethylene diisocyanate and tetramethylene. Diisocyanate, 0-, m-
Or P-xylylene diisocyanate (XDI), hexahydromethaxylidene diisocyanate (HXDI), tolylene-2,4-diisocyanate (TDI), tolylene-
2.6-diisocyanate, diphenylmethane-4.4 '
-Diisocyanate (MDI), naphthalene-1.5-diisocyanate, diphenyl-4.4'-diisocyanate and the like. Examples of the polyether diol used in the present invention include:
Polyethylene glycol (PEG), polypropylene glycol (PPG), polyoxyethylene-polypropylene block copolymer, polytetramethylene glycol, polytetramethylethylene glycol, polybutadiene glycol, hydrogenated polybutadiene glycol, bisphenol A base diol, acrylic polyether diol And the like. The average molecular weight of the polyether diol is 400 to 2,000. If it is less than 400, the viscosity becomes too high at the time of application as an adhesive, making it difficult to handle.
In addition, the pot life becomes short, and handling on an applicator becomes difficult, which is not preferable. If the average molecular weight exceeds 2,000, the perforation and printing durability of the adhesive layer after the production of base paper are undesirably reduced. Diisocyanate and polyether diol are equivalent ratio
Use in the range of NCO / OH = 1.5-2.0. If NCO / OH <1.5, the porosity of the adhesive layer after the production of the base paper decreases, which is not preferable. Further, the viscosity of the obtained urethane prepolymer increases, and the workability is poor. When NCO / OH> 2.0, the isocyanate monomer remains, which is not preferable for sanitation. The glycidyl-type epoxy compound having no active hydrogen as the component (B) of the present invention has a polar group having an epoxy ring only at the terminal and having a hydrogen atom not bonded to the carbon base paper, for example, a hydroxyl group (-OH ), mercapto group (-SH), amino group (-NH _2), an imido group (= NH), a carboxyl group (-COO
It is an epoxy compound having no H) or the like. Specifically, the following compounds are mentioned. (A) phenolic epoxides Alkyl phenol diglycidyl ether (cashew), resorciepoxide, aromatic polyglycidyl (eg, tetraglycidoxytetraphenylethane), novolak epoxide (epichlorohydrin as an initial condensate of novolak phenolic resin Acted). (B) Bisphenol-type epoxide A reaction of bisphenol and equhydrin in a ratio of 1: 2. (C) Glycol-type epoxides Ethylene glycol, propylene glycol, glycerin or those obtained by reacting polyglycols with epichlorohydrin, and ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether. (D) Ester epoxides wherein carboxyl group hydrogen is substituted with glycidyl group, for example, diglycidyl adipate, diglycidyl phthalate, glycidyl dimer acid ester. (E) N-glycidylamine epoxide tetraglycidylaminodiphenyl methanediglycidylaminophenyl. (F) Those containing sulfur, silicon, phosphorus-containing epoxide thiochol diglycidyl, glycidyl silicon, and phosphorus. The components (A) and (B) of the urethane-based adhesive used in the present invention are mixed and used when producing heat-sensitive stencil printing base paper, and the components (A) and (B) are mixed. In order to facilitate the adhesion between the porous support and the plastic film, the urethane-based adhesive preferably has a viscosity of about 10,000 to 100,000 cps / 25 ° C., and is heated in advance for this purpose. In addition, the component (A) and the component (B) are preferably used as a mixture. The method of producing the urethane prepolymer with the component (A) may be a method of producing stepwise or a method of batch charging. For the production of urethane prepolymer,
The component (B) may be produced by the above method in a state where the components are mixed in advance. The flow start temperature after the reaction and curing of the urethane adhesive used in the present invention is 240 ° C. or less, in order to improve the piercing property, prevent the adhesion of scum to the thermal head and prevent the sticking phenomenon, and A flow start temperature higher than 50 ° C. at which the adhesion is reduced is required, preferably 80 to 160
° C. The amount of the adhesive used in the present invention is 0.3 to 2.5.
range of g / m ² are suitable, preferably, it is 0.5 to 1.5 g / m ^2. The plastic film used in the present invention may be any plastic film (especially highly oriented or stretched film) that can be used for heat-sensitive stencil printing.
Films such as polyvinylidene chloride, a vinylidene chloride-vinyl chloride copolymer, and a copolymer containing propylene as a main component are used, and a polyester (PET) film and a polyvinylidene chloride film are suitable. The porous support may be any porous material that does not substantially have a perforation property when heated and that allows ink to pass through during printing, such as Japanese paper manila hemp, thin paper or nonwoven fabric of polyester fiber, polyester fiber, silk Screen gauze and the like are preferred. Incidentally, the urethane-based adhesive used when producing the heat-sensitive stencil printing base paper of the present invention includes various additives, for example, an antioxidant, a release agent and the like, as long as the properties are not impaired. Any amount may be blended. Examples 1 and 2 are described below. Example 1 As a component (A), urethane obtained from diphenylmethane-4,4'-diisocyanate and polypropylene glycol having an average molecular weight of 1,000 so that the equivalent ratio of NCO / OH becomes 1.9. 100 parts by weight of prepolymer, 50 parts by weight of diglycidyl ether of bisphenol A obtained from 1 mol of bisphenol A and 2 mol of epichlorohydrin (Toto Kasei Chemicals: Epototh YD-8125) as component (B), component (A) And the component (B) were stirred and mixed at room temperature to prepare a urethane-based adhesive. Incidentally, the flow start temperature of the cured adhesive is, using a Koka type flow tester, load 20kg, orifice diameter 1.0 × 1.0mm,
It was measured at a heating rate of 6 ° C./min, and the outflow starting temperature was 130 ° C. The urethane-based adhesive thus obtained is appropriately heated so as to have a viscosity of 1000 cps, supplied to a coating roller of a laminator, and a polyester film (thickness 2 μ) and a porous support (8.5 g / bonding the Manila hemp tissue paper) of m ^2. At that time, the applied amount of the adhesive was 0.8 g / m ² . Next, 1 part by weight of silicone rubber (Toray Silicone Co., Ltd. product: Toray Silicone Rubber SE5004) and silicone resin (Toray Silicone Co., Ltd. product: Toray Silicone Resin SR2402) 1.5
A solution prepared by dissolving 0.0075 parts by weight of a silicone resin catalyst (product of Toray Silicone Co., Ltd .: Q-1-2407) and 0.5 parts by weight of isostearyl alcohol in 97 parts by weight of n-hexane was applied. Incidentally, the coating amount is 0.2 g / m2 in dry solid content.
^{Was 2} . After application, dry with hot air and leave at room temperature for 3 days.
A thermosensitive stencil printing atom of the present invention was prepared. The atoms created as described above were perforated using a lithographic DF9800 (manufactured by Riso Kagaku Corporation), a plate making machine using a thermal head. Next, lithographic AP9800II (manufactured by Riso Kagaku Kogyo Co., Ltd.)
Was used to print. At this time, (1) running property of the base paper, (2) adhesion of perforated scum to the thermal head, and (3) print image quality were evaluated. The results are shown in Table 1. Table 1 also shows the following examples and reference examples. Example 2 As the component (A), 23.2 parts by weight of hexamethylene diisocyanate and polytetramethylene ether glycol 7 having an average molecular weight of 1.000 were used so that the equivalent ratio of NCO / OH was 1.8.
Use 6.8 parts by weight. 20 parts by weight of glycidyl para-tert-butyl benzoate (Fuso Chemicals: PES-10) as the component (B), and the components (A) and (B) are charged together in a reaction vessel. In the mixed state, a urethane prepolymer was synthesized from the component (A) to obtain a urethane-based adhesive. The flow start temperature of the cured adhesive was measured under the same conditions as in Example 1, and was found to be 150 ° C. Thereafter, the heat-sensitive stencil sheet of the present invention was manufactured under the same conditions as in Example 1, and the printing was performed by making a plate. Example 3 The component (A) is the same urethane prepolymer 10 as in Example 1.
0 parts by weight, and the component (B) is a diglycidyl ester of hexahydrophthalic acid (Mitsui Petrochemical Epoxy: EPOMI
KR-540) using 50 parts by weight of these (A) and (B)
The components were stirred and mixed at room temperature to produce a urethane-based adhesive. The flow start temperature of the cured product of the adhesive was 151 ° C. as a result of measurement under the same conditions as in Example 1. Thereafter, heat-sensitive stencil printing base paper was manufactured under the same conditions as in Example 1. Then, plate making and printing were performed. Example 4 The component (A) is the same urethane prepolymer as in Example 2.
100 parts by weight, and (B) 50 parts by weight of trimethylolpropane triglycidyl ether (Kyoei Oil & Fat Chemical Industrial Product: Epolite 100 MF). These components (A) and (B) are stirred and mixed at room temperature to form a urethane. A system adhesive was manufactured. The flow start temperature of the cured adhesive was measured under the same conditions as in Example 1, and was 148 ° C. Thereafter, heat-sensitive stencil printing base paper was manufactured under the same conditions as in Example 1. Then, plate making and printing were performed. Comparative Example 1 A polyester film and a porous support were bonded together using only the component (A) without using the component (B) in Example 1 as an adhesive. The flow start temperature of the cured adhesive was 200 ° C. by the same measurement method as in Example 1. Comparative Example 2 In Example 1, component (A) was 45 parts by weight, and component (B) was 55 parts by weight.
The polyester film and the porous support were bonded together using an adhesive in parts by weight. The flow start temperature of the cured adhesive was 55 ° C. by the same measurement method as in Example 1. [Effects of the Invention] In the present invention, as an adhesive, an epoxy compound having no active hydrogen is blended with a urethane prepolymer, and a heat-sensitive stencil printing base paper is manufactured using the compound. Excellent heat sensitivity and easy perforation. In particular, due to the action of the epoxy compound having no active hydrogen in the adhesive component, even when the base paper of the present invention is in close contact with the thermal head at the time of perforation, heat fusion of the plastic film and generation of perforated scum are possible. No adhesion to the thermal head occurs. Therefore, the heat-sensitive stencil sheet of the present invention is excellent in perforation and resolution as shown in Table 1. Thus, with the base paper of the present invention, it has been difficult to obtain a good image until now. In a thermal plate making using a heating element such as a thermal head as a heat source, an excellent printed matter can be obtained. It was directly connected to office automation equipment (eg, word processors, personal computers, etc.), further improving resolution.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Satoshi Chonan               2-20-15 Shimbashi, Minato-ku, Tokyo Ideal course               Gaku Kogyo Co., Ltd.

Claims (1)

(57) [Claims] In a heat-sensitive stencil printing paper in which a plastic film is adhered to a porous support, as an adhesive, (A) a diisocyanate and a polyether diol having an average molecular weight of 400 to 2,000 such that the equivalent ratio of NCO / OH is 1.5 to 2.0. A urethane prepolymer component using (B) a glycidyl-type epoxy compound having no active hydrogen or more, comprising (A) and (B) as main components;
(A): (B) = 10: 10 to 10: 1, using a urethane-based adhesive having a flow start temperature after curing of 50 to 240 ° C.
A heat-sensitive stencil sheet, wherein the plastic film is bonded to a porous support.