JPS5891900A - Papermaking method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a wet machine papermaking method in which calcium ions and/or divalent metal ions such as asbestos slate boards, pulp cement boards, gypsum slab boards, and calcium silicate are present in the raw material slurry. relates to a papermaking method characterized by containing artificial fibers such as glass fibers and fibers, and adding carboxymethyl cellulose to control papermaking characteristics.

Asbestos slate boards, pulp cement boards, gypsum slab boards, calcium silicate boards, etc. are manufactured using the wet machine papermaking method, which enables continuous mass production with uniform quality.

This typical manufacturing method uses cement, valve, stone wax, slag, other inorganic powders, asbestos fibers, etc. as raw materials and adds water to form a slurry. This slurry is filtered through a wire mesh cylinder with an appropriate mesh. Then, it is formed into a so-called green sheet containing raw material solids and water, which is then continuously transferred to an endless felt and wound around a making roll.

Building materials such as asbestos slate made by this wet machine method obtain filtration properties and fiber reinforcement effects for the finished product by incorporating asbestos fibers.

In particular, the filtration properties of asbestos are an important point when using a wet machine.The surface properties of well-opened asbestos are such that it can be used as an adsorbent, and it has good water retention. When mixed into a raw material slurry, it has good adhesion and mutual capture with particles in the slurry. The characteristics of this asbestos fiber create a difference between the slurry water level in the vat of the wet machine papermaking machine and the water level in the cylinder roll, that is, a head difference, which enables the solid content in the slurry to be made into paper. Although asbestos fibers have favorable characteristics in the wet machine papermaking process, they are specified in the Ordinance on the Prevention of Hazards from Specified Chemical Substances, and are subject to various regulations if they are mixed into products in excess of 5 weight limits. In addition, the working environment is regulated by the Industrial Health Act.

Most of the asbestos is imported from overseas, and its production areas are extremely unevenly distributed.
There are also unstable factors that can easily be manipulated in terms of price and supply.

Therefore, despite its excellent properties, the use of asbestos fibers is increasingly restricted due to social and economic factors.

Under these circumstances, artificial fibers such as glass fibers and carbon fibers are being considered as asbestos substitutes. However, these asbestos substitutes have poor water retention properties and have too good drainage properties, making it difficult to obtain favorable results in terms of papermaking.This is because many man-made fibers do not have the surface properties of asbestos fibers. So, the freeness becomes too good and the head difference (
The difference between the water level of the raw material slurry in the vat and the water level in the cylinder roll decreases, making papermaking difficult. In addition, solid particles in the raw material slurry Therefore, in the paper manufacturing method of asbestos slate boards, etc., the present inventor has investigated the paper manufacturing characteristics when artificial fibers such as glass fibers and carbon fibers are mixed into the raw material slurry as a substitute for asbestos. As a result of intensive research on improving
It was discovered that by adding carboxymethyl cellulose, it was possible to improve and control the papermaking characteristics.

The present invention is characterized by adding carboxymethyl cellulose (hereinafter referred to as CMC).
I will explain about it.

CMC1 is produced by reacting alkali cellulose with monochloroacetic acid, and its molecular formula is as follows.

(C,H,0,(OH),(OCH,C00Na))
.

This Na easily reacts with divalent metal ions in a slurry system such as cement slurry where these ions are present. For example, when CMC1 is added to cement slurry, it is thought that the following reaction occurs. Ca++ in the cement slurry undergoes a substitution reaction with Na in CMC.

In other words, the cement particles in the cement slurry are CIVIC.
The cement particles and CM C combine to form CM
Cement particles strongly adhere to the fibers of C. In addition, by adding Ca ions to CMC, the filtration characteristics of the cement slurry during paper making can be greatly changed, and the filtration characteristics can be controlled by the amount added.

The amount of CMC added is several ppm to cement slurry.
250 ppm, below which the effect is less and 100 ppm.
If it exceeds ppm, the viscosity becomes too high and it is difficult to handle, and there is also the problem of contamination of the felt.

The following basic experiment confirmed that when CMC is added to CM cement slurry, its filtration properties are improved, even for divalent metal ions other than Ca ions, which are contained in cement, stone, slag, etc. First, in this experiment, a sheet machine paper making apparatus shown in FIG. 1 was used. This solo-type sheet machine paper making device has a wire mesh (A) with 80 meshes arranged inside, and is partitioned by the wire mesh (A).
The upper part is the sample tank part (B) and the lower part is the filtrate receiving tank part (C).Below this filtrate receiving tank part (C), a filtrate drain pipe is formed. A cock (e) is provided in the part. First, with the cock (e) closed, fill the filtered water tank (c) with water up to the wire mesh (a), then pour the cement slurry into the sample tank (b) and make sure the slurry is evenly distributed. After confirming that it has been dispersed, when the cock (E) is opened, the water in the filtrate receiving tank (C) is drained through the filtrate drain pipe), and most of the solids contained in the cement slurry are removed. remains on the top of the wire mesh (A), and a portion of it becomes a dilute slurry that is drained through the filter water pipe (A). The drained dilute slurry is taken, the drained solid content is measured, and the percentage of the drained solid content is determined from the solid content initially mixed into the cement slurry.

V[Water solid content (a) is based on the following formula.

In addition, the filtration time until the solid content in the cement slurry is filtered onto the wire mesh (A) is measured.

The filtration characteristics of Cemen)

The raw materials for the cement slurry are as follows: Hecement: Boltland cement pulp: Kraft paper asbestos Cotton: 6D-4 (opened cotton) Glass fiber: Alkali-resistant glass fiber, trade name Mineron Soft type single fiber diameter 19μm1 Length 16% CMC: Carboxymethyl cellulose Product name "Sunrose 1" The formulation and measurement data are shown in Table 1. The slurry concentrations of cement, pulp, asbestos, and glass fiber in the table are based on 3 weight ratios, and the concentration of CMC is This is the concentration for this slurry.

Formulation &1 in Table 1 is a standard asbestos slate board formulation, but this formulation and 0 formulation I62, whose filtration characteristics were evaluated based on the filtration characteristics and the solid content of wastewater, are CMC, which is a feature of the present invention.
A3 to A6 are comparative examples in which CMC was not added, and A3 to A6 are examples of the present invention in which CMC was added.

Blend No. 2. The material contains 1% by weight of glass fiber and 5% by weight of asbestos, and does not contain CMC. The filtration time is short, the solid content of the wastewater is as high as 10.2%, the freeness is too good, and the papermaking properties are poor.

In formulations A3-6, the amount of CMC added was gradually increased, and the measured values are close to those of current standard asbestos slate.

By adjusting the amount of CMC added in this way, the filtration characteristics of the slurry can be freely controlled, and the characteristics of conventional asbestos substitutes such as poor water retention and excessive drainage, which were the defects of many artificial fibers, can be controlled. However, the addition of CMC has greatly improved its application in a wide range of fields.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a sheet machine paper-making device for measuring filtration characteristics Patent applicant Nippon Valqua Industries Co., Ltd. Figure 1 Procedural amendment (method) April 12, 1980 1 Indication of case 1988 Patent application No. 191506 2. Name of the invention Paper-making method 3. Person making the amendment Relationship with the case Patent applicant 4. Date of amendment order March 5, 1980 (Shipping date: March 60) As shown in the attached sheet CMC: Carboxymethyl cellulose product The slurry # degree of cement, pulp, asbestos, and glass fiber in Table 0 showing the composition and measurement data in Sunrose Table 1 is 51 degrees, and the concentration of CMC is the degree of this slurry. table

Claims (1)

[Claims] A papermaking method characterized by containing artificial fibers such as glass fibers and carbon fibers in the raw material slurry 4 of a wet machine papermaking method in which calcium ions and/or divalent metal ions are present, and adding carboxymethyl cellulose.