JPH0717427B2 - Hydraulic inorganic papermaking product and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Technical Field of the Invention The present invention relates to a hydraulic inorganic papermaking product which is essentially excellent in mechanical performance without using asbestos, and a production method for obtaining such a papermaking product. It is about.

B Conventional Technology and Problems Thereof A hydraulic inorganic papermaking product is a composite mainly composed of a fiber material such as asbestos and a hydraulic material such as cement as represented by an asbestos slate board.

Its main production method is to prepare a fiber component such as asbestos and a hydraulic binding component such as cement together with other additives in an amount of 5 to 30% by weight of an aqueous dispersion (papermaking slurry), which is then placed on a round or long-net. It is a wet papermaking method in which the product is obtained by making it into paper, dehydration, molding, curing and drying.

This method provides inexpensive, high-strength, non-combustible materials with high productivity with simple equipment, and such products are widely used as building materials in a wide range of fields.

The role of asbestos in such a hydraulic inorganic papermaking product is (1) the effect of imparting high productivity in the papermaking process (a) imparting uniform dispersibility of the fiber used together (b) particulates mainly composed of hydraulic substance Capturing substances and imparting appropriate water-based properties (c) Delamination with a making roll or molding roll,
Prevention of wrinkles and water cracking (d) Surface smoothness and moldability during press molding (e) Strengthening of green sheet (improving handleability) (2) Ensuring product physical properties (reinforcing hydraulic material) It is said that (a) improvement of mechanical properties such as bending, tension, impact strength, etc. (b) Addition of dimensional stability (c) Improvement of durability. Furthermore, the characteristics inherent to hydraulic materials such as non-combustibility are hardly reduced. In addition, it is a very inexpensive substance.

As described above, the role of asbestos in the inorganic papermaking product is extremely important, which is why it is said that an inexpensive product having excellent physical properties cannot exist without the presence of asbestos.

Asbestos's excellent properties are that it is a fibrillar substance, has a high affinity with hydraulic substances, high strength, high Young's modulus, inorganic fiber, high water retention, etc. caused by.

On the other hand, asbestos generates dust in the air when manufacturing, processing, and constructing a product containing the asbestos.

In recent years, it has been revealed that when fine dust of asbestos is inhaled into the human body, it causes lung cancer and the like, and its use gradually begins to be restricted by laws and regulations, and there is even a sign that the use is prohibited.

Furthermore, asbestos-producing countries are unevenly distributed in specific countries, and there is a problem of depletion of sources.

Under such circumstances, it is strongly desired to provide a hydraulic inorganic papermaking product which does not contain asbestos at all, and which has the same high productivity and high performance as that of using asbestos instead of the hydraulic inorganic papermaking product containing a large amount of asbestos.

Conventionally, attempts have been made to produce a product by a wet papermaking method by substituting asbestos with another substance, but it is not sufficient and is only used for a very limited purpose.

The reason is that as described above, there is no substitute that satisfies the excellent hydraulic substance trapping property of asbestos, the prevention of delamination, the imparting of moldability, and the excellent reinforcing property.

JP-A-55-121947, 55-121948 are pulp, flocculant,
The combination of glass fibers improves the dispersibility of glass fibers and the ability to capture hydraulic substances, etc., and is a substitute for asbestos, but the dispersibility and the ability to capture are insufficient. Especially, regarding the trapping property, although the effect of the flocculant is apparent, it is at most 70%
This is a problem and it is a problem in operational production. Furthermore, problems such as delamination have not been solved.

Japanese Patent Publication No. 57-60315 discloses a technique in which pulp and a relatively thin fiber (for example, rock wool) enhance the trapping property of a hydraulic substance and alkali glass fiber improves the physical properties of the product.

This technique also has an insufficient trapping property for hydraulic substances, and has a serious problem of delamination and moldability. Further, since the alkali glass fiber has poor dispersibility, the reinforcing effect is insufficient and the surface property of the product is also poor.

JP-A-59-73463 makes an attempt to improve the trapping property of hydraulic substances with bentonite and pulp and to enhance the reinforcing effect with vinylon.

Although the trapping property of the hydraulic material shows the effect of using bentonite, it is insufficient in operation production, and the dispersibility of the reinforcing fiber is poor unless the usage method of bentonite is specified,
It is difficult to obtain the reinforcing effect.

None of the above-mentioned known techniques is sufficient to substitute asbestos having various excellent properties as described above, and far falls short of high productivity when using asbestos and excellent product physical properties.

In order to substitute the asbestos having such excellent properties, the present inventors consider that the point is to combine various components and bring out a synergistic effect in addition to the respective properties, and as a result of earnest research, the present invention was reached. It was done.

C Structure of the Invention The gist of the invention is (a) a dispersion of bentonite having a swelling degree of 2 to 10 defined in the invention and (b) a pulp, (c) a polyvinyl alcohol-based or polyacrylonitrile-based reinforcing fiber, ( d) A natural or / and artificial fibrous inorganic substance is dispersed, and then (e) a papermaking slurry prepared by adding a hydraulic inorganic substance such as cement, and (f) a flocculant is added to produce a papermaking slurry. A hydraulic inorganic papermaking product and a method for producing the same.

The present inventors have proposed Japanese Patent Application No. 58-131451 based on the same idea as the present invention of combining various components,
The dispersibility of fibers such as reinforcing fibers, the ability to capture hydraulic inorganic substances such as cement, the property of preventing delamination, the surface property, and the moldability are somewhat insufficient, and the results of an examination focusing on these improvements are The present invention is characterized by using bentonite having a specified degree of swelling. That is, the synergistic effect of the properties of bentonite itself and other substances provides a high productivity and high performance wet papermaking product without asbestos.

The first problem of the wet papermaking product in the asbestos-free system is poor dispersibility of fibrous materials such as reinforcing fibers.

Such dispersibility is significantly improved only by using bentonite of the present invention with a specified degree of swelling in a specified manner.

In other words, bentonite having a swelling degree of 2 to 8 was similarly added to an aqueous dispersion prepared by dispersing the pulp, which is a constituent of the present invention, in a concentration such that it corresponds to 1 to 8% by weight based on the total solids of the papermaking slurry. After adding 2 to 20% by weight based on the amount, or adding pulp to the bentonite dispersion, an aqueous dispersion is prepared by stirring and dispersing with a pulper or the like. A polyvinyl alcohol-based or polyacrylonitrile-based reinforcing fiber and a natural and / or artificial fibrous inorganic substance (abbreviated as fibrous inorganic substance above) are added to the aqueous dispersion, and the mixture is stirred and dispersed to obtain a predetermined amount of hydraulic inorganic substance. In addition, it is the size to form the papermaking slurry.

The addition of polyvinyl alcohol-based or polyacrylonitrile-based reinforcing fibers and fibrous inorganic substances to an aqueous dispersion of bentonite and pulp is the point of improving the dispersibility of the reinforcing fibers and the like.

The degree of swelling of bentonite means a numerical value obtained based on the following measuring method. (A) Toyo Paper No. 5C 110 mmφ of known weight is placed on a glass funnel of about 60 mmφ, and about 1.5 g of bentonite is weighed and placed on the paper.

(B) Inject a proper amount of distilled water at room temperature from above to wet the sample.

(C) After that, fix the funnel at the position where the lower part of the paper is submerged in the water surface and leave it for 24 hours to replenish the sample with the required amount of water. Water will be replenished by the capillary action of the paper.

(D) Take out the sample swollen with water after leaving it from the funnel together with the paper, transfer it to a porcelain Buchner funnel (for 110φ) and weigh it after suction to remove the adhered part of the paper (Wp) (e) Next 105 ° C After drying in a drier to a constant weight, weigh it (W ₂ ) (F) Separately weigh the paper separately and use it as the tare weight (wet paper W ₃ , dry paper W ₄ ) (G) Then, the degree of swelling is calculated.

Satisfactory dispersibility can be obtained only by adding reinforcing fibers and the like to an aqueous dispersion of bentonite and pulp having a swelling degree of 2 to 10, and bentonite and pulp may be used alone or as reinforcing fibers. Satisfactory results cannot be obtained even if bentonite or a water dispersion of pulp is added.

The second problem in the production of a wet papermaking product in a system without asbestos is the trapping property of hydraulic inorganic substances such as cement and other particulate substances as described above.

Furthermore, when winding and laminating on a making roll like a round net method, cracking phenomenon when developing into a sheet after cutting, delamination between laminated sheets, moldability such as corrugation, and surface smoothness are poor. There's a problem. The solid content trapping ratio in the papermaking slurry must be 85% or more, preferably 90% or more. Such various problems include bentonite having a swelling degree of 2 to 10 with respect to the solid content of the papermaking slurry, 2 to 10% by weight, pulp 1 to 8% by weight, fibrous inorganic substance 1 to 5% by weight, and hydraulic inorganic substance. It has been found that only with a combination of 50-500 ppm of flocculant a satisfactory solution is made.

The bentonite of the present invention has a montmorillonite group mineral as a main component, and its content is at least 40% or more.

Examples of montmorillonite group minerals include montmorillonite,
Heiderite, nontronite, hectorite, saponite, etc.

The degree of swelling of such bentonite is 2 to 10, preferably 4 to
Must be 7. When the amount is less than 2, there is no effect when the amount is small, and when the amount is large, the capturing property of the particulate matter is improved, but it does not contribute to the improvement of the dispersibility of the fiber.
Also, because the sheet becomes too hard, delamination is increased,
Also, the formation of small cracks significantly deteriorates the moldability. If it is larger than 10, the swelling is too large and the water quality deteriorates, and a uniform sheet cannot be made because the cylinder wire netting and felt are soiled, and the making roller part or the green plate does not stick to the roller surface and productivity is improved. It will be significantly reduced.

The amount of bentonite is 2 with respect to the solid content of the papermaking slurry.
Must be ~ 20% by weight. When the degree of swelling is small within the scope of the present invention, it is preferably large, and when large, the opposite is preferable. If it is less than 2% by weight, no effect can be expected, and if it is more than 20% by weight, the same phenomenon as when the swelling degree is too large is exhibited, which is not preferable. The particle size is preferably 150 mesh or less for use.

The pulp content in the present invention must be 1 to 8% by weight based on the solid content of the papermaking slurry. If it is less than 1% by weight, the trapping property of particulate matter is lowered, and if it is more than 8% by weight, the flame retardancy of the product is impaired and delamination is increased, which is not preferable.

The type of pulp may be natural pulp or synthetic pulp. As the natural pulp, unbleached or bleached pulp from softwood or hardwood is mainly used, but pulp obtained from straw, bamboo, cotton, hemp, ramie, kozo, mitsumata or the like can also be used. Also, recovered waste paper obtained from newspapers, paper bags, cardboard boxes, etc. can be used.

The Canadian freeness is preferably 30 to 750 ml, more preferably 50 to 300 ml.

As synthetic pulp, polyolefin pulp, such as SW
P (polyethylene-based pulp manufactured by Mitsui Zerapack) and polyaramid-based pulp, such as Kevlar pulp (manufactured by Deyupon)
Can be used, and any fibrillar substance having a shape similar to these can be used.

The fibrous inorganic substance in the present invention has a thickness of 3 to 15 μm.
m, length 0.1 to 10 mm, other than asbestos may be natural or man-made.

As the artificial fibrous inorganic substance, there are glass-based fibers such as general A glass and E glass fiber, and alkali resistant glass fiber to which zirconium oxide is added, and further shirasu fiber, slag wool, rock wool, ceramic fiber. Etc. can be used, or two or more kinds of the fibers and the like can be used in combination.

Such a fibrous inorganic substance is particularly effective for improving the trapping property of granular substances such as cement at the time of paper making due to a synergistic action with other substances, and the effect is shorter when the length is shorter.
Therefore, the length of the fibrous inorganic substance is the length when the paper is made,
That is, it means the length of the product width, not the length of the raw material. Even if the length of the raw material is 10 mm or more, it may be broken by a mixer, pulper, cheest, etc., and 60% or more may be 0.1 to 10 mm, preferably 1 to 5 mm. The diameter of the fiber is 3 in terms of diameter
If it is less than μ, it is said that the water quality is abnormally deteriorated and it is not good for the health. There is no effect at 15μ or more. The compounding amount is 1 to 5% by weight based on the solid content of the papermaking slurry. 1
If it is less than 5% by weight, the effect is poor, and if it is more than 5% by weight, the green sheet becomes too hard and the conformability to the making roll is poor, and cracks and delamination are likely to occur when developing into a sheet shape. The moldability is also poor.

The coagulant may be a common coagulant. Organic, inorganic, or anionic, nonionic, cationic, or ionic ones may be used, but anionic polymer flocculants generally used as cement flocculants are preferably used.

The amount of the flocculant used is preferably 50 to 500 ppm with respect to the hydraulic inorganic substance. If it is less than 50 ppm, the effect is poor, and if it exceeds 500 ppm, it is difficult to form a uniform sheet because the cohesive force is too strong and the agglomerates become large blocks or the water is too good to have a head difference. In addition, it contaminates felt and results in loss of productivity.

As described above, only by combining the specified bentonite, pulp, fibrous inorganic matter, and coagulant in the specified amounts, the second problem in the production of the hydraulic wet papermaking product without asbestos is solved. It has become possible to solve problems such as insufficient capture of particulate matter such as hydraulic inorganic substances, cracks when developing into a sheet form from a making roll, delamination, poor moldability and surface property.

The reason for this is not clear, but it is considered that there is a synergistic effect in view of the surprisingly large effects that are expected from the effects of the individual products.

Asbestos has the role of improving the paper-making property and reinforcing the product as described above. In the absence of asbestos, a combination of reinforcing fibers is generally required, and it is necessary to use known reinforcing fibers in the present invention.

Reinforcing fibers are the weak points of hydraulic inorganic cured products, such as tension,
Although it improves bending and impact strength, it is particularly important to improve tensile strength and bending strength. Fibers for that purpose must have tensile strength, high Young's modulus, good adhesion to hydraulic minerals such as cement, alkali resistance, harmless to health, and cheaper. Is desirable.

The most preferable reinforcing fiber satisfying the above conditions is a polyvinyl alcohol (hereinafter abbreviated as PVA) fiber, and a polyacrylonitrile fiber is also preferably used. These reinforcing fibers must have a tensile strength of 5 g or more per denier and a Young's modulus of 90 g or more per denier.

The compounding amount is 0.5 to 5% by weight with respect to the solid content of the papermaking slurry,
It should preferably be 1 to 3% by weight. If it is less than 0.5% by weight, there is no reinforcing effect, and if it exceeds 5% by weight, fractional defects occur and a uniform sheet cannot be obtained, and it becomes expensive.

Further, the fineness is preferably in the range of 0.1 to 20 denier.
The aspect ratio (ratio of fiber diameter to fiber length) is 200 to 900.
Is a preferable range in terms of both dispersibility and reinforcing property.

The hydraulic inorganic materials that can be used in the present invention include the following. A typical example is Portland cement. Portland cements include ordinary Portland cements, moderate heat Portland cements, early strength Portland cements, ultra early strength Portland cements, white Portland cements and sulfate resistant Portland cements. There are blast furnace cement, silica cement and fly-ash cement as mixed cement. Alumina cement as a special cement, super rapid hardening cement, colloidal cement,
Oil well cement is used. Semi-hydrated gypsum using gypsum and mixed hydraulic material of hydrated gypsum and slag,
It is also possible to use magnesium and the like, but basically, any hydraulic inorganic substance may be used.

It is also possible to replace a part of the hydraulic inorganic substance with another substance depending on the purpose. For example, lime type such as calcium sulfaluminate as an expansive admixture, perlite as a lightening agent, shirasu balloon, other silica sand shirasu, mica, serpentine rock, charcoal, clay, kaolin, talc, vermiculite, Silica, sepiolite, attapulgite, etc. can be used.

D Effects and Uses of the Present Invention As described above, the present invention uses the specified materials of bentonite, pulp, polyvinyl alcohol-based or polyacrylonitrile-based reinforcing fiber, fibrous inorganic material, and coagulant in a specific method. In addition, by compounding within a specific range, synergistic effects between materials are added to each property, and it has succeeded in providing a high productivity and high performance asbestos-free hydraulic wet inorganic papermaking product. It is a thing.

The asbestos-free hydraulic inorganic papermaking product obtained according to the present invention can be used as a substitute for the conventional asbestos-containing product, but its application can be further expanded by not containing asbestos. Can be expected.

To describe application examples, corrugated asbestos boards, roofing materials such as Ankel, asbestos-free flat plates, perlite boards, pulp cement boards, siding materials, curtain walls, fireproof partition walls, outer wall panels and other structures, ships, etc. There are interior and exterior materials or asbestos-free pipes.

E Examples The present invention will be described below with reference to examples.

Example-1 Bentonite with a swelling degree of 4 which has been previously swollen by swelling it in water and 130 ml of Canadian acid freeness NUKP (unbleached softwood pulp) are added to a pulper with a slurry containing white water, and a concentration of about 2% is applied for 10 minutes. It was stirred.

After that, slag wool having an average diameter of 4 μm which is a fibrous inorganic substance and PVA fiber which is a reinforcing fiber are added at the same time and stirred for 2 minutes.

The slag wool was put in a pulper in advance, added with siaer, and then sieved to 0.5-2 mm.

The PVA fiber used had a fineness of 1.6 denier, strength of 12.5 g / dr (dr stands for denier), Young's modulus of 320 g / dr, and fiber length of 5 mm.

A hydraulic material, Portland cement, was added to the aqueous dispersion, stirred for 5 minutes, and then transferred to Tiesto.
A 120 g / l papermaking slurry was used.

While adding the anionic flocculant (IK Flock T-210 from Iorikawa Kori) and the required amount of white water to the papermaking slurry, the papermaking slurry was introduced into a papermaking tank (batt) and made on a 60 mesh mesh net,
Wind up on a making roller and cut the raw plate after cutting at 50 kg / c
It was pressure molded at m ² . The curing conditions were heating at 50 ° C. for 24 hours, and then left in an air-dried state for 4 weeks.

The compounding amount and data are shown in Table 1. The dispersibility shown in the table means the dispersion state of the fibrous substance, and when the papermaking slurry is made into a net, the unevenness on the net is observed and the dispersion is very good. The state is ◎, the poor dispersion state with a lot of unevenness is ×, and the interval is 2
It was divided into ranks and marked as ○ and △. The water level of the butt is ◎ when it is possible to make a sufficiently uniform sheet, and when the water level is hardly taken and only a uniform sheet can be made, or when the water is too bad and the papermaking slurry exceeds the butt, x The intermediate ranks were evaluated qualitatively as ○ and △. The capture rate (%) of Portland cement, etc. is calculated from the slurry concentration (W ₁ ) before paper making in the paper making tank and the wastewater concentration (W ₂ ) discharged through the gauze. Sought as. The delamination property was qualitatively determined by manually delaminating the green plate after the making roll.
The state in which the layers are not clear even when a force is applied in the peeling direction is difficult to peel, and the state in which the layers are easily peeled is x.

Regarding the cracks at the time of molding, the raw plate after the making roll was subjected to ordinary corrugation and the cracked state was observed.

Bending strength is JIS A1408 "Bending test method for building boards"
The average value in the vertical and horizontal directions is shown. Since the compounding amount of the reinforcing fiber changes substantially when the trapping property of the hydraulic material or the like changes, the yield-corrected bending strength is shown to compare the true reinforcing property.

The impact strength was measured by the Izod test method of JIS K-7110 only in the longitudinal direction without notching.

Comparative Examples-1 to 7 The compounding amount and the measurement data are shown in Table-1.
1 to 4 are cases in which any one of the five components other than the hydraulic substance among the substances constituting the present invention was lacking, and Comparative Examples-5 to 7 were cases in which two types were missing, It belongs to the known technology described.

Reference Example-1 An asbestos board having a compounding composition consisting of asbestos 6D 13%, unbeaten NUKP 2%, and the balance Portland cement was made into paper by the same paper making machine as in Example-1 and used as a reference example.

From Table-1, it is obvious that Example-1 has excellent paper-making properties and physical properties as compared with Comparative Examples, and is equal to or higher than Reference Example-1 using asbestos.

On the contrary, if even one of the constituent elements of the present invention is lacking, it is not possible to obtain papermaking properties and physical properties comparable to asbestos. Comparative Example-6-
8 belongs to the known art, it can be understood how great the effect of the present invention is when compared with these.

Examples-2 to 3 and Comparative Examples-9 to 10 The amount of bentonite in Example-1 was 3% (Example-
2), 8% (Example-3), 1% (Comparative Example-9), 15%
Table 2 shows the results obtained by the same method as in Example 1 except that (Comparative Example-10) was used and high-strength acrylic fiber (strength 8.5 g / dr, Young's modulus 150 g / dr) was used as the reinforcing fiber.
Summarized in.

Except for the examples, there are some problems, which are not preferable.

Examples -4 to 5; Comparative Examples -11 to 12 NUKP canadian freeness in Example-1 is 200 ml.
Example 2 except that the compounding amounts were 2% (Example-4), 7% (Example-5), 0.5% (Comparative Example-11) and 10% (Comparative Example-12). The results of papermaking by the same method as in No. 1 are summarized in Table 3.

The examples are all satisfactory results, but the comparative examples have some problems. Comparative Example-7, which contains a large amount of pulp, is not preferable because the dimensional stability, which is a characteristic of the hydraulic inorganic plate, is extremely poor.

Example-6; Comparative Examples-13 to 14 The content of slag wool in Example-1 was 2% (Example-
6), 0.2% (Comparative Example-13) and 15% (Comparative Example-14) except that the results of papermaking according to Example-1 are all shown in Table-4.
It was shown to.

In Comparative Example-13, the dispersion of the fibrous substance was poor, the reinforcing property was lowered, and the trapping property of Portland cement etc. was unsatisfactory. In Comparative Example-14, the green plate is hard and delamination occurs, resulting in poor moldability. Also, when it was developed into a sheet from a making roll, it exhibited a cracking phenomenon.

Example-7; Comparative Example-15 Papermaking was carried out by the same method as in Example-1 except that the swelling degree of bentonite was set to 8 and the compounding amount was set to 3% in Example-1 (Example-7). Papermaking was carried out in exactly the same manner as in Example-7, except that bentonite was added at the same time as Portland cement in Example-7 (Comparative Example-1).
Five). The respective results are shown in Table-5.

Although good dispersibility of fibrous substances such as reinforcing fibers when bentonite is added according to the method of Example, the dispersibility is poor in the case of Comparative Example-15 in which the addition order of bentonite is changed, and thus the reinforcing effect is obtained. Also, the surface quality of the product was not good.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C04B 16:02 16:06) (72) Inventor Masaki Okazaki 1-2-1 Kaigan-dori, Okayama-shi, Okayama Stock Kuraray Co., Ltd. (72) Inventor Sotaro Itaya 1-2-1, Kaigandori, Okayama City, Okayama Prefecture Kuraray Co., Ltd. (56) References JP 59-73463 (JP, A) JP 58-116120 ( JP, A) JP 55-62833 (JP, A) JP 54-136708 (JP, A) JP 50-147545 (JP, A) JP 55-100256 (JP, A) JP JP-A-51-62811 (JP, A) JP-A-55-118810 (JP, A) JP-A-54-139633 (JP, A) JP-B-51-40034 (JP, B1)

Claims (10)

[Claims] 1. Reinforcement of bentonite based on solid content of papermaking slurry of 2 to 10% by weight (weight% based on solid content of papermaking slurry unless otherwise specified), 1 to 8% of pulp, polyvinyl alcohol-based or polyacrylonitrile-based reinforcement A hydraulic inorganic papermaking product comprising 0.5 to 5% of fibers for use, 1 to 5% of natural or / and artificial fibrous inorganic substances, 50 to 500 ppm of coagulant (hydraulic inorganic substances), and the balance mainly consisting of hydraulic inorganic substances. 2. The hydraulic inorganic papermaking product according to claim 1, wherein the degree of swelling of bentonite is 2-10. 3. The hydraulic inorganic papermaking product according to claim 1 or 2, wherein the reinforcing fiber has a fineness of 0.1 to 20 denier, an aspect ratio of 200 to 900, and a tensile strength of 5 g / denier or more. 4. The hydraulic property according to claim 1, wherein the natural or / and artificial fibrous inorganic material has a diameter of 3 to 15 μm (equivalent to yen) and a length of 0.1 to 10 mm. Inorganic paper products. 5. The Canadian freeness of pulp is 30 to 75.
The hydraulic inorganic papermaking product according to any one of claims 1 to 4, which has a volume of 0 ml. 6. An aqueous dispersion prepared by adding 2-10% of bentonite to an aqueous dispersion of 1-8% pulp or adding pulp to a dispersion of bentonite and stirring to disperse it in an amount of 0.5-5.
% Polyvinyl alcohol-based or polyacrylonitrile-based reinforcing fiber, natural or / and artificial fibrous inorganic substance 1 to 5%, and the remaining mainly mainly hydraulic inorganic substance is added to the dispersion liquid stirred and dispersed. To 50
A wet papermaking method for a hydraulic inorganic product, which comprises performing papermaking while adding a coagulant of 500 ppm (hydraulic inorganic). 7. The wet papermaking method for a hydraulic inorganic papermaking product according to claim 6, wherein the degree of swelling of bentonite is 2-10. 8. The hydraulic inorganic papermaking product according to claim 6 or 7, wherein the reinforcing fiber has a fineness of 0.1 to 20 denier, an aspect ratio of 200 to 900, and a tensile strength of 5 g / denier or more. Wet papermaking method. 9. The hydraulic property according to any one of claims 6 to 8, wherein the natural or / and artificial fibrous inorganic material has a diameter of 3 to 15 μm (equivalent to yen) and a length of 0.1 to 10 mm. Wet papermaking method for inorganic papermaking products. 10. The pulp has a Canadian freeness of 30 to.
It is 750 ml, The wet papermaking method of the hydraulic inorganic papermaking product in any one of Claims 6-9.