JPH0580424B2 - - Google Patents

Description

[Detailed description of the invention]

A Technical field of the invention The present invention does not use asbestos or pulp at all,
The present invention relates to a method for producing hydraulic inorganic paper products (hereinafter abbreviated as paper products) with excellent performance using ultra-fine organic synthetic fibers, an inorganic dispersant, and a polymer flocculant. B. Prior art and its problems Paper-made products, such as asbestos slate boards, contain asbestos, and asbestos plays an important role in economically ensuring the paper-making properties and physical properties of such products.
However, in recent years, the health problems caused by asbestos have become clear, and there is a strong demand for paper products that do not use asbestos at all, and the development of manufacturing technology is actively underway. A typical example of a method for producing paper products is the hatch-check method, and the role of asbestos in this method is to provide paper-making properties such as trapping cement particles, as well as to provide bending, tensile strength, and other reinforcement noncombustibility (JIS surface It is to provide physical properties such as tests).
Replacing asbestos in paper products is extremely difficult because asbestos has excellent properties, and it is common knowledge in the industry that it is impossible to replace it with a single substance. Therefore, since significantly different physical properties are required for imparting paper formability and imparting physical properties, most proposals have been made to replace asbestos with different substances. From the perspective of imparting physical properties, that is, reinforcement, organic synthetic fibers such as polyvinyl alcohol fibers, polyacrylonitrile fibers, and aramid fibers, and inorganic fibers such as alkali-resistant glass fibers are used, and among them, polyvinyl alcohol fibers are particularly effective for reinforcement. It has attracted attention because of its effectiveness, and a considerable amount is used as an asbestos substitute. On the other hand, from the viewpoint of replacing asbestos in imparting paperability, the majority of proposals are to use natural pulp. However, paper products using such pulp have problems with durability, dimensional stability, freeze-thaw stability, and nonflammability due to deterioration, water absorption, or flammability of the pulp itself, and these problems can be minimized as much as possible. In order to
Several proposals have been made to reduce the amount of pulses used. For example, the invention described in Japanese Patent Application Laid-Open No. 60-5049 attempts to solve the negative problem of poor water quality by increasing the beating degree of the pulse considerably to capture cement particles, and by mixing a small amount of virgin pulp. In addition, we are also proposing a technology that uses swellable inorganic fillers such as sepiolite and bentonite to increase the cement particle trapping effect through interaction with pulses. The present inventors have also conducted various studies on pulses and auxiliary agents, and have reached the conclusion that a pulse of approximately 3% is indispensable in order to stably produce paper products. The presence of such amount of pulp is not sufficient to eliminate the harmful effects of pulp as described above. Therefore, as a result of repeated research to obtain a paper-made product that does not use pulp at all from a different perspective, the invention was filed as Japanese Patent Application No. 18063-1983. In other words, it is a paper-made product using ultra-fine Pinilon having specific physical properties with a fineness of 0.5 denier or less, and a paper-making method thereof, and the combination of such Pinilon and a flocculant surprisingly allows stable paper-making without using any pulp at all. Moreover, the excellent reinforcing effect of the ultra-fine pinion allows almost satisfactory physical properties to be obtained, which is an epoch-making technology that breaks conventional wisdom. However, as further studies progressed, it was discovered that the dispersibility of ultra-fine vinylon was insufficient, and the resulting paper product had problems as a commercial product. In other words, because the fibers of ultra-fine pinylon are thin, the number of fibers in the ultra-fine pinylon is overwhelmingly larger than that of normal denier (around 2 denier) fibers even with the same aspect ratio. and tend to separate. As a result, fibers tend to gather on the surface (back side) of the fleece during papermaking, causing problems such as peeling between the fleece layers, poor appearance due to fuzz on the surface, and reduced reinforcing properties. The present inventors have arrived at the present invention as a result of intensive research to solve such problems. C. Purpose of the Invention The present invention improves the appearance by improving the dispersibility of ultrafine fibers and obtaining uniform papermaking slurry in a papermaking method using ultrafine fibers without using any asbestos or pulses. The purpose is to provide an asbestos-free, pulse-free paper product with good quality and excellent performance without delamination. D. Structure of the invention The present invention uses a hydraulic substance such as cement and
Organic synthetic fibers having a denier of 0.05 to 0.5 and an aspect ratio (ratio of fiber length l to its diameter d, l/d) of 200 to 1500 (hereinafter expressed as weight based on the solid content of the paper), and 0.01 to 5% This is a method for producing a paper product by adding a polymer flocculant to a uniform slurry made of an inorganic dispersant. The first requirement of the present invention is to use a specific inorganic dispersant in order to obtain a papermaking slurry in which ultrafine organic fibers are uniformly mixed with other solids such as cement in which the dispersibility of ultrafine organic fibers is improved. The inorganic dispersants of the present invention are sepiolite, attapulgite, palygorskite, and sodium bentonite (hereinafter abbreviated as sepiolite, etc.), and one type or a combination of two or more of these is used. The amount of the inorganic dispersant added is
0.01-5% is preferred. If it is less than 0.01%, there will be no dispersion effect for ultrafine fibers, and if it exceeds 5%, the viscosity of the slurry will become too high, resulting in poor dehydration of water on the round screen and of fleece, resulting in water cracking on the making roll, which will reduce paper-forming properties. becomes worse. Furthermore, it becomes difficult to press and the bulk specific gravity of the product decreases, causing problems such as a decrease in reinforcing effect, an increase in dimensional changes due to increased water absorption, and a decrease in stability due to freezing and thawing.In addition, it is economically disadvantageous. Become. If the amount exceeds 1%, the dispersing effect of the inorganic dispersant will hardly change, so considering the negative aspects of adding inorganic dispersants and economic efficiency, it is recommended to
1% is a more preferred range. Note that using an inorganic dispersant that has been previously dispersed and disaggregated in a colloidal form contributes more to the dispersion effect. The second requirement of the present invention is to use ultrafine strength organic synthetic fibers. Such ultrafine fibers capture solid content such as cement and serve to reinforce the hydraulic hardening body. It is essential that the fineness is 0.05 to 0.5 denier. If the denier is less than 0.05 denier, the ability to trap hydraulic substances and the like is good, but the dispersion is insufficient even when the inorganic dispersant of the present invention is used, and the fiber itself cannot be manufactured economically, which is not preferable. Moreover, if it exceeds 0.5 denier, the ability to capture solids such as hydraulic substances will decrease, making stable papermaking impossible. In view of both dispersibility and reinforcing properties, the aspect ratio is suitably 200 to 1500, and the amount of fiber added is 0.1 to 5%, more preferably 0.5 to 3%. Regarding the mechanical properties of the fibers, in terms of reinforcing effect, strength and Young's modulus need to be 5 g or more per denier and 90 g or more per denier, respectively, and if they are less than that, the reinforcing effect is poor. Basically, any ultra-fine organic synthetic fiber may be used as long as it satisfies the characteristics described above, but polyvinyl alcohol fibers and polyacrylonitrile fibers are preferred from the viewpoint of adhesiveness, and they may be used alone or in combination of two or more. A combination of these may also be used. The third requirement is to use a polymer flocculant. A polymer flocculant is an essential component indispensable for improving the ability to capture solids such as cement. Commercially available types may be used, and anionic polymer flocculants are particularly suitable. The amount added is preferably 5 to 500 ppm, more preferably 50 to 200 ppm, based on the solid content of papermaking. If it is less than 5 ppm, the solid content will have poor agglomeration effect, and if it exceeds 500 ppm, it will coagulate too much and the aqueous property will be too good, and the difference in head in the paper making tank will not be taken care of, making it impossible to form a uniform sheet, causing fetish stains, and causing economic problems. It is also undesirable from a sexual perspective. As the hydraulic material, cements such as ordinary Portland cement, blast furnace cement, silica cement, and alumina cement can be used. Furthermore, it is also possible to use hemihydrate gypsum, dihydrate gypsum and slag, or a mixture of these and cement. Other additives include process passability of paper-made products,
It is also possible to use substances for the purpose of improving moldability and performance or reducing costs. For example, a fine inorganic material having a diameter or fiber length of 1 x 10 ^-2 to 1 x 10 ^-4 mm can be used in combination for the purpose of preventing delamination, dissolving into the making roller, and imparting surface smoothness. Typical examples of such substances include natural or synthetic carbonates such as heavy tankal and light tankal, kaolin, clay, silica flour, talc, fly ash, and fibrous wollastonite. If the diameter or fiber length exceeds the above range, it may be used after pulverizing, and the amount added is preferably 1 to 20%. The sepiolite, etc. of the present invention has the same effect as such substances in the range of 1% or more, and therefore, in such a range, it is also possible to replace sepiolite, etc. with the above substances. Other lightweighting agents (e.g. expanded perlite, shirasu balloons, foaming agents),
Expanding agents, gold mica, white mica, serpentine, silica sand, etc. can be added. In addition, the fibers include rock wool, slag wool, ceramic wool, and glass fiber powder, and the reinforcing components include polyvinyl alcohol fibers of 0.5 denier or more, polyacrylonitrile fibers, carbon fibers, steel fibers, aramid fibers, polyacrylate fibers, and polypropylene fibers. , polyethylene fibers, etc., or a combination of two or more thereof can be used together. Furthermore, synthetic pulp, natural pulp, etc. may also be used, but from the viewpoint of the purpose of the present invention, it is preferable to avoid using natural pulp as much as possible. The paper-making method of the present invention is carried out according to the conventional general paper-making method, in which ultrafine organic synthetic fibers and an inorganic dispersant are mixed and dispersed in a normal mixer such as a pulper, and then cement is added. Make a papermaking slurry of ~30%. After adding a polymer flocculant and water to the slurry and forming it onto a round screen or fourdrinier, a predetermined paper product is formed by a conventional method. The polymer flocculant is preferably added immediately before the papermaking tank, and after the flocculant is added, it is not preferable to apply strong mechanical stirring that would destroy the formed aggregates. The inorganic dispersant is preferably mixed and stirred with the organic synthetic fibers and cement to obtain the most uniform slurry, and by adding a coagulant to the slurry, it becomes a uniform aggregate, which is suitable for papermaking. It can be raised. If it is not possible to add, mix, and stir at the same time, it must be added at least before adding the flocculant. After adding the flocculant, the original dispersion effect cannot be achieved. The present invention is characterized in that ultrafine organic fibers are uniformly dispersed in a hydraulic substance using an inorganic dispersant, and the uniform aggregates flocculated by the flocculant are drawn onto a wire mesh by the overaction of the ultrafine organic fibers. The purpose of the present invention is to provide a paper-made product with excellent performance that does not contain either asbestos or pulp, and the key point of the present invention is to use an inorganic dispersant such as sepiolite. itself is publicly known. For example, in the invention described in Japanese Patent Publication No. 60-5049, 1 to 10% sepiolite is used, but the purpose and structure are completely different from those of the present invention. The invention of the published patent is an attempt to reduce the amount of pulp, which plays a role in cement trapping, as much as possible in order to reduce its negative effects, as is the case with technology. This is what we are trying to do. That is, the addition of sepiolite only becomes meaningful in the presence of pulp. The present invention was originally filed by patent application
As shown in the invention of No. 59-18063, sepiolite has a sufficient effect of capturing cement particles etc. in combination with a flocculant without the presence of pulp, and as long as ultrafine organic synthetic fibers are used, sepiolite does not have any cement particles. It does not contribute to improving catchability. On the other hand, when pulp is used in combination with ultrafine organic fibers, the pulp contributes to the dispersion effect of the ultrafine fibers, and no effect of sepiolite is observed at all. That is, the effect of adding sepiolite is manifested only when ultrafine organic synthetic fibers are used and pulp is not used, and the effect is only to improve dispersibility. Therefore, this invention is completely different from the invention of Japanese Patent Application No. 1983-5049. Sepiolite is also described in JP-A No. 60-21836, but in the invention of this published patent, the fineness of the reinforcing fibers is 15 denier or less, but it is reasonable to consider it to be a common denier considering the examples. However, there is no suggestion that sepiolite is particularly effective for ultrafine fibers of at least 0.5 denier or less, and in addition, it is an important requirement to use it in combination with short-length inorganic fibers such as rock wool. That is, the synergistic effect of sepiolite and rock wool improves the ability to capture cement particles, etc., and improves the dispersion of fibers. Therefore, it is clearly different from the present invention. Note that % indicating the amount of a component in the present invention indicates weight % unless otherwise specified. This will be explained below using examples. Example 1, Comparative Example 1, Reference Example 1 Ultrafine synthetic fibers were collected at a concentration of 2% based on the solid content, stirred and dispersed in water, and an inorganic dispersant and Portland cement as listed in Table 1 were added. Approximately 3
The mixture was mixed and stirred for a minute to form a slurry with a total solid concentration of 20 g/min. The ultra-fine synthetic fiber used is PVA fiber with a fineness of 0.20 dr (DR is an abbreviation for denier) and a tensile strength of 14.3.
g/dr, Young modulus 320g/dr, fiber length 3
mm, aspect ratio 640. Further, the inorganic dispersant used was one that had been sufficiently dispersed and disintegrated in advance. The slurry was placed in a 1000 ml graduated cylinder, and 1.0 g/aqueous solution of an anionic polymer flocculant (Sunfloc AK-100P manufactured by Sanyo Chemical Co., Ltd.) was added and stirred, and the state of dispersion was observed. At this time, the addition rate of the flocculant to the solid content was 150 ppm. The dispersion state is evaluated as ○ if the PVA fibers and matrix components are uniformly aggregated, and ◎ if it is particularly good.
The case where most of the PVA fibers were floating and most of the cement particles were coagulated and precipitated and separated from the fibers was marked as ×, and the case in between was marked as △.

[Table] Cement: Ordinary Portland cement manufactured by Onoda Cement Co., Ltd. In each case, in Example 1, PVA fibers, cement, and an inorganic dispersant were mixed, and a coagulant was added to cause coagulation and precipitation. In Test Nos. 1, 2, 3, and 4, when the amount added was changed, the dispersibility was best at around 0.5%, followed by 0.3%. There is no other difference within the scope of the present invention. In all of Nos. 7, 10, and 11 of Comparative Example 1, most of the PVA fibers did not coagulate together with the matrix component and floated when a coagulant was added. It will settle if left standing for a while. The appearance was that the supernatant layer was followed by a fiber precipitate layer, and below that was a matrix component layer. Test Nos. 8 and 9 were conducted with a small amount of inorganic dispersant and with a large amount of inorganic dispersant, but satisfactory results were not obtained in either case. Reference example 1 is a case where asbestos was added. Even when added in small amounts, the dispersion effect was poor. Example 2, Comparative Example 2 PVA fiber 2%, silica flour 5%,
The ingredients listed in Table 2 as an inorganic dispersant and the remainder were adjusted with a pulper to a slurry concentration of 10% using a composition of ordinary Portland cement, and the slurry was prepared while diluting with white water. In addition, when making paper, the solid content
100 ppm of polymer flocculant was used. (i) Description of raw materials used PVA fiber; 0.20 dr, tensile strength 14.8 g/dr,
Young modulus 310 g/dr, cut into fiber length 3 mm Sepiolite; Atta200 (Union Kasei Co., Ltd.) Sodium bentonite; Chikuzen No. 5 (manufactured by Shinagawa Kazai Co., Ltd.) Silica flour; SF powder (manufactured by Nippon Heavy Chemical Co., Ltd. average particle size 0.36 μ) Agglomeration Agent: Sunfrotsuku AK-100 (manufactured by Sanyo Kasei Co., Ltd.) (ii) Compound composition: summarized in Table 2 (iii) Manufacturing method for slate board Pour white water into a pulper with a slushier and add the specified amount of silica flour and inorganic dispersant. After stirring, PVA fibers are added, and finally, ordinary Portland cement is added, and after stirring for about 3 minutes, the mixture is transferred to Chiest and used as a slurry for papermaking. A flocculant prepared by dissolving 1.0 g of this slurry at 100 ppm was added to a mixing box in front of the papermaking tank, and the necessary amount of white water was added and mixed, introduced into the papermaking tank (vat), and then papered using a 60-mesh circular screen. , rolled up on a making roll and cut the raw board to a weight of 75Kg/cm ²
Pressure molded. After curing at 50°C for 24 hours, it was air-cured at room temperature for 4 weeks to obtain a 6 mm thick slate board. (iv) Evaluation method Dispersion state: The dispersion state of PVA fibers on the front and back surfaces of the made-up cement fleece was observed. The case where a large number of fibers were fuzzed on the free surface was evaluated as ×, and the case where the fibers were uniformly dispersed in the cement sheet and not unevenly distributed on the surface was evaluated as ◎. The results were divided into two ranks: ○ and △. Papermaking yield: It is the capture rate of solid content in papermaking slurry such as cement and inorganic dispersant. The papermaking yield (%) was determined as follows: (1 - solid content concentration in round screen wastewater)/solid content concentration in vat) x 100. Delamination: Qualitative judgment was made by manually peeling off the layers of the raw board after being rolled. A state in which the interlayers were unclear and it was difficult to peel off was rated as ○, a state in which the layers were easily peeled off was rated as ×, and a state in between was rated as △. Bulk specific gravity: According to JIS A 5418, the test piece was placed in an air dryer with a stirrer and heated at 105±5℃.
It was determined from the weight and volume after 24 hours of drying. Bending strength: Measured according to JIS A 1408 "Bending test method for architectural boards," and expressed as the average value in the papermaking direction (vertical direction) and the direction perpendicular to it (horizontal direction).

[Table] In all of Example 2, good paper formability and slate plate physical properties were obtained. Test Nos. 14 to 17 showed good dispersion. Test No. 18 of Comparative Example 2 is Milcon SS
The addition rate of (sepiolite) is the case where it is added beyond the scope of the claims of the present invention. Although there were no problems with the dispersion state and delamination, the water content during paper making was poor, the moisture content after press molding was high, and the bulk specific gravity of the product was low. Therefore, the bending strength was also poor. Test No. 19 is the case where no inorganic dispersion material is used. The dispersion state was poor, delamination occurred, and the bending strength decreased. In addition, many fibers were seen entangled on the surface and the appearance was poor.

Claims (1)

[Claims] 1. Hydraulic substances such as cement have a fineness of 0.05 to 0.5.
Organic synthetic fibers with a denier and aspect ratio (ratio of fiber length to diameter) of 200 to 1500 from 0.1 to
5% (hereinafter expressed as weight % based on the papermaking solid content),
An anionic polymer flocculant is added to the slurry containing 0.01 to 5% of an inorganic dispersant in the process before the papermaking tank.
A method for producing a hydraulic inorganic paper product characterized by adding 500 ppm. 2. The method for producing a hydraulic inorganic paper product according to claim 1, wherein the amount of the inorganic dispersant added is 0.1 to 1%. 3. The method for producing a hydraulic inorganic paper product according to claim 1 or 2, wherein the organic synthetic fiber is a polyvinyl alcohol-based synthetic fiber or a polyacrylonitrile-based synthetic fiber. 4 Tensile strength of organic synthetic fiber is 5 per denier
The method for producing a hydraulic inorganic paper product according to any one of claims 1 to 3, wherein the young modulus is 90 g or more per denier. 5. The method for producing a hydraulic inorganic paper product according to any one of claims 1 to 4, wherein the inorganic dispersant is one or a combination of two or more selected from sepiolite, attapulgite, palygorskite, and sodium bentonite. .