JPH04235094A - Production of porous tissue for thermal stencil printing - Google Patents

Abstract

PURPOSE:To improve transport property by adding a curing agent and/or an antistatic agent to porous tissue for thermal stencil printing consisting of 100% polyester to improve a nerve of the porous tissue and increase an antistatic effect. CONSTITUTION:Paper layer of a perfect paper material for 100% polyester porous tissue are formed and squeezed at a press part. After that, a curing agent and/or an antistatic agent is sprayed to the web before a Yankee drier and dried. For example, the web is made by containing 50% composite polyester binder fiber of a size of 2 denier and a fiber length of 5mm and adding thereto polyester fibers of a size of 0.5, 0.3, and 0.1 denier in the ratio of 30%, 15%, and 5%, respectively. A prepared liquid of a melamine resin curing agent is sprayed to the web before the inlet of the Yankee drier for the porous tissue. Immediately after spraying, an increased water content is removed by being sucked by a felt. After that, the web is dried by the Yankee drier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a porous thin paper used as a base paper for heat-sensitive stencil printing which is subjected to a plate-making method using a writing perforation method using a thermal head.

[Prior art] As a porous thin paper used for heat-sensitive stencil printing base paper,
Until now, washi paper made of 100% natural fibers such as linen has been the mainstream. However, while these prints have good print density, they always have white spots due to the bound fibers, so they have the disadvantage of poor resolution. Therefore, 100% of synthetic chemical fibers such as polyester
Since Japanese paper made of 100% synthetic fibers has excellent resolution without white gaps due to binding fibers, general users desire high resolution in the market. This is preferable because it satisfies the requirements.

Compared to Japanese paper made from 100% natural fibers such as hemp, Japanese paper made of 100% synthetic chemical fibers is weaker and has stronger static electricity, so it has problems with transportability within a plate-making printing press. In other words, wrinkles occur during perforation with the thermal head and do not wrap around the rotary drum, wrinkles appear on the printed image receiving paper, or the stencil printing base paper loses its elasticity and bends during transportation, causing it to move forward. Since it may cause problems such as not being conveyed, it has not yet become mainstream among porous thin papers for heat-sensitive stencil printing.

[Problems to be solved by the invention] Conventional porous thin paper for heat-sensitive stencil printing made of 100% synthetic chemical fibers is weak and has strong static electricity, so it wrinkles during transportation during the plate-making process of a plate-making printing machine. Because of this, it became impossible to wrap the printing plate around the rotary drum, causing quality problems such as making printing impossible or causing wrinkles to appear on printed receiver paper. Or, a quality problem occurred in that the plate was not transported inside the hardware equipment and could no longer move forward, making it impossible to work.

In order to eliminate these quality problems, an effective method is to attach a hardening agent and/or an antistatic agent to the porous thin paper to increase the stiffness and improve the conductivity of the porous thin paper.

Conventional methods for applying hardening agents and/or antistatic agents to porous thin paper include the tab size method, size press method, and curtain coater method. After shaping the paper, the liquid must be applied to the paper by passing it through these facilities, and then drying it again using a Yankee dryer, which lengthens the paper-making process, increases paper loss, and increases energy costs.
Not efficient. Also, after being wound once in a paper machine, it may be processed in an off-machine, but this will definitely increase costs. In either method, the conventional technology efficiently
Or, it is not possible to make the process cheaper.

The present invention improves transportability by adding a curing agent and/or antistatic agent to porous thin paper for heat-sensitive stencil printing made of 100% polyester in an efficient process, improving the stiffness of the porous thin paper and increasing the antistatic effect. The purpose is to provide a manufacturing method that can improve the

[Means for Solving the Problems] The method for producing porous thin paper for heat-sensitive stencil printing of the present invention includes the following steps:
Production in which a paper layer is formed from a complete paper stock of 100% polyester porous thin paper, water is squeezed out in a press part, a hardening agent and/or an antistatic agent is spray applied to the web in front of a Yankee dryer, and then dried with the Yankee dryer. It's a method. The reason why the process design of the method for producing porous thin paper for heat-sensitive stencil printing of the present invention was designed as described above will be described.

In the case of the above-mentioned method of spraying a curing agent and/or antistatic agent onto the web in front of a Yankee dryer, conventional techniques such as impregnation methods such as the tab size method, size press method, and curtain coater method require the addition of one Yankee dryer. This is because it is very efficient in terms of process, since it is only necessary to install a spray coating device in front of the entrance of the Yankee dryer, whereas it is necessary to process on-machine or off-machine.

The problem with the manufacturing process of the present invention, in which porous thin paper is directly spray coated and then dried with a Yankee dryer, is that the drying load becomes extremely large due to the addition of moisture from the spray coat. The two points are that the spray breaks down the formation of the paper layer. The following describes how these two problems were addressed.

First, we will discuss the increase in drying load. In the present invention, the porous thin paper made of 100% polyester has a wet paper moisture content of approximately 70% after press water removal.

If this is sprayed and the liquid is spread over the entire wet paper, the moisture content will be approximately 90-95%. If the basis weight of the porous thin paper is calculated as 10 g/m2, the increase in moisture will be about 70 to 170 g/m2. If the wet paper enters the drying process in a Yankee dryer with this much moisture in it, it will be necessary to either reduce the paper speed or raise the dryer temperature significantly, both of which are undesirable. Therefore, in the present invention, a method of dewatering using felt suction immediately after spray coating is adopted. If the felt suction has a dehydration capacity commensurate with the amount of spray applied, the moisture content of the wet paper can be reduced to the same level as before spray application. That is, in the present invention, immediately after spray coating, water is dehydrated using felt suction to adjust the moisture content to the same level as after press squeezing, so there is no need to worry about an increase in drying load. In addition to dehydration, the effect of felt suction is that the hardening agent and antistatic agent sprayed on the paper penetrate well into the paper layer, helping the chemicals to fully exert their effects.

Next, regarding the question of whether spraying will destroy the formation of the paper layer, spraying is performed so that the particle size of the spray is 30 μm or less, so the formation will not be destroyed.

Preferred examples of the curing agent include melamine resin, epoxy resin, dialdehyde starch, urethane resin, and modified polyamide resin. No matter which one of these hardening agents you choose, it will still be 2
The stiffness of porous tissue paper can be strengthened by appropriately combining more than one type of agent, but among these, the hardening agent for melamine resin is the most effective in increasing stiffness. However, in the case of melamine resin, after adding the melamine resin at the time of liquid preparation, add a reactive catalyst of 5 to 15% on a solid/solid basis to the melamine resin and a formalin scavenger of 30 to 30% on a solid/solid basis to the melamine resin. You need to add 40%. When a hardening agent such as this melamine resin is sprayed onto porous tissue paper and dried, the bonds between fibers in the paper layer are strengthened, the elastic modulus increases, and the paper becomes stiffer.

The amount of hardening agent applied by spraying is approximately 1.5 to 2.0 g/m2 or more, depending on the type, to obtain the required rigidity. In other words, if this amount of hardening agent is applied, the Gurley stiffness of the porous tissue paper will be 15 mg or more, and the wrinkles caused by the conveyance caused by the weak stiffness when perforating heat-sensitive stencil printing base paper with a heat-sensitive head will be eliminated. You can. The Gurley stiffness of 15 mg or more is a value obtained from experience, and with this stiffness, wrinkles will not occur during transportation during drilling.

Antistatic agents include acrylic acid ester polymer type, polyoxyethylene polymer type, which are commercially available as antistatic agents.
It is also preferable to use one or a combination of two or more of phosphoric acid ester polymers. When these antistatic agents are sprayed onto porous thin paper and dried, the porous thin paper improves its hygroscopicity and conductivity, so that a sufficient antistatic effect can be obtained. Regarding ionicity, nonionicity is most preferred. This is because when perforating with a heat-sensitive head in the process of making a plate for heat-sensitive stencil printing base paper, if the material is cationic, anionic, or amphoteric, the heat-sensitive head may be corroded.

The amount of antistatic agent deposited by spraying provides a sufficient effect as a conductive treatment, and the amount of the antistatic agent deposited is equivalent to the surface resistivity of the porous thin paper of 10 8 to 10 9 Ω. When a heat-sensitive stencil printing base paper is made using this material and perforated with a heat-sensitive head, it is possible to eliminate wrinkles during transportation due to static electricity.

When spraying an antistatic agent, it is necessary to dilute it to an appropriate dilution ratio depending on the type of liquid and add it, and it is common to dilute the undiluted solution by 40 to 50 times, depending on the type of liquid. . Therefore, the spray amount may exceed 100 g/m2, so when on-site, it is necessary to have equipment such as a suction box with a corresponding dehydration capacity before entering the Yankee dryer after spraying.

[Examples] The present invention will be explained in detail below with reference to Examples, but the present invention is not limited only to these Examples.

Incidentally, a heat-sensitive stencil printing base paper was prepared using the porous thin paper of the present invention, and its various properties during plate making and printing were evaluated using the following evaluation methods. The evaluation of various properties during plate making and printing in Table 2 is expressed using this evaluation method.

(1) Print density 5: Dark 4: Slightly dark 3: Normal (2) Resolution 5: High sensitivity 4: Slightly high sensitivity 3: Normal (3) Plate making wrinkles caused by stiffness After making 20 sheets, the wrinkles were removed. It is expressed by the number of sheets.

For example, if one sheet is wrinkled, write it as 1/20.

(4) Plate making wrinkles caused by static electricity It is written in exactly the same way as (3).

The physical properties of porous tissue paper are measured using JIS L1085 for basis weight and density, and JIS L1085 for Gurley stiffness.
It was carried out using SL1079.

The surface resistivity was measured using a high resistance meter manufactured by Yokogawa Hewlett-Packard.

Hereinafter, the present invention will be explained by examples.

Example 1 Composite polyester binder fiber with a fineness of 2 denier and a fiber length of 5 mm (core melting point 250-260°C, sheath melting point 11
0°C) 50%, 30% polyester fiber with a fineness of 0.5 denier fiber length 5 mm, fineness 0.3 denier fiber length 5 mm
15% of polyester fibers having a fineness of 0.1 denier and 5% of polyester fibers having a fiber length of 3 mm are mixed as paper stock, and a web having a basis weight of 10.0 g/m2 is made using a cylinder paper machine.

A preparation of a melamine resin curing agent is sprayed onto the web of this porous thin paper in front of the entrance of the Yankee dryer using a spray device. The composition of the liquid preparation is melamine resin curing agent 1
00 parts (solid), reactive catalyst 10 parts (solid), and formalin scavenger 30 parts (solid). The coating amount was such that the melamine resin curing agent was applied in a solid amount of 2.0 g/m2. The particle size of the spray was 30 μm or less. Immediately after spraying, remove the increased moisture using felt suction, then
Dry with Yankee dryer. The Yankee dryer temperature was 125°C.

Example 2 Paper-making was carried out in exactly the same manner as in Example 1, except that an acrylic acid ester polymer-based antistatic agent was used as the spray preparation.

The solution was prepared by diluting the stock solution of the antistatic agent 50 times with water.

The coating amount was 2.0 g/m2 using a cloth.

Example 3 Paper-making was carried out in exactly the same manner as in Example 1, except that the solution to be sprayed was a mixed solution of a melamine resin curing agent and an acrylic acid ester polymer-based antistatic agent.

The coating amount is 2 as solid as melamine resin hardener.
．． 0g/m2, the amount of antistatic agent applied is 2.0g with cloth
/m2.

Comparative Example 1 Paper-making was carried out in exactly the same manner as in Example 1, except that the spray before the Yankee dryer inlet was omitted.

Comparative Example 2 After papermaking was carried out in exactly the same manner as in Comparative Example 1, it was impregnated with a mixed solution of a melamine resin curing agent and an acrylic acid ester polymer-based antistatic agent according to the tab size using an off-machine coater.

The coating amount was exactly the same as in Example 3.

A thermoplastic polyester film having a thickness of 3 μm was laminated to the porous thin paper produced in Examples 1 to 3 and Comparative Examples 1 to 2 using a vinyl acetate adhesive to produce a base paper for heat-sensitive stencil printing.

This heat-sensitive stencil printing base paper was subjected to stencil printing using a Risograph manufactured by Riso Kagaku Kogyo Co., Ltd. and evaluated.

Table 1 shows production examples of porous thin paper (Examples 1 to 3, Comparative Examples 1 to 2).

Table 2 shows the physical property values and plate-making printing characteristics of the porous thin paper.

[Effects of the Invention] Conventional porous thin paper for heat-sensitive stencil printing made of 100% polyester has better image quality than 100% natural fiber, but on the other hand, the stiffness of the sheet is weak and the static electricity is strong, making it difficult to use during the plate-making process. Resolving this problem was an important issue as it was evaluated as easily wrinkled during transportation and difficult to use due to its hardware.

In the present invention, in order to eliminate wrinkles during transportation, the porous thin paper is strengthened and treated to be conductive. For the former method, an effect can be obtained by applying a curing agent such as melamine resin, and for the latter method, an antistatic agent such as an acrylic acid ester polymer can be applied, but the problem lies in the production technology for applying it.

Conventional impregnation methods and others require either an off-machine operation or two drying steps, resulting in a lot of waste.

Therefore, in the present invention, by spraying in front of the entrance of the Yankee dryer and removing the increased moisture by felt suction, on-machine operation can be performed with extremely few steps and no reduction in paper speed, resulting in increased productivity and speed. Hardening agents and antistatic agents can be applied with ease.

The significance of the present invention is that it makes it possible to establish the quality of porous tissue paper for heat-sensitive stencil printing made of 100% polyester, and to enable efficient production.

Claims (4)

[Claims] Claim 1: A method for producing porous thin paper for heat-sensitive stencil printing made of 100% polyester fibers, in which a hardening agent and/or antistatic agent is applied to the web after forming a paper layer and squeezing the water in a press before a Yankee dryer. Spray a solution containing
A method for producing porous thin paper for heat-sensitive stencil printing, the method comprising drying with the Yankee dryer. 2. The method for producing porous thin paper for heat-sensitive stencil printing according to claim 1, wherein the moisture increased by spray coating is removed by felt suction before a Yankee dryer. 3. Claim 1, wherein the curing agent is made of one or a combination of two or more of melamine resin, epoxy resin, dialdehyde starch, urethane resin, and modified polyamide resin.
Or the method for producing porous thin paper for heat-sensitive stencil printing according to 2. 4. The thermosensitive material according to claim 1 or 2, wherein the antistatic agent is made of one or a combination of two or more of acrylic ester polymers, polyoxyethylene polymers, and phosphoric ester polymers. A method for producing porous thin paper for stencil printing.