JPS605049A - Manufacture of inorganic hardened body - 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 [Technical Field] The present invention relates to a method for producing an inorganic cured body used as a building material. More specifically, the present invention relates to a method for producing an inorganic hardened material such as a cement-based inorganic building material without using asbestos.

[Background Art] Inorganic hardened bodies containing cement as a binder and asbestos as a reinforcing material have been widely used. This is because when asbestos is used as the reinforcing fiber, the reinforcing effect on the inorganic hardened material becomes remarkable, and the inorganic hardened material can be produced by a papermaking method suitable for mass production such as the bee-nick papermaking method. In this method, a slurry containing raw materials is made into a paper making machine such as a Hachinik paper making machine, and the obtained excipient is cured to produce an inorganic hardened body. At that time, papermaking becomes possible if asbestos is used in an amount of 5% by weight or more based on the solid content of the raw material.

However, the use of asbestos poses a risk of causing asbestos pollution, and continuing to use asbestos in the future poses a problem in terms of protecting the social environment.

Therefore, in recent years, research has been actively conducted on inorganic hardened materials that do not contain asbestos. An example of this is an inorganic hardened material that contains pulp instead of asbestos, and such products are already on the market. However, this inorganic cured product had the following drawbacks and was unsuitable for use as a general building material. That is, it has the disadvantage of not being non-flammable. In order to make this inorganic hardened material using the papermaking method, it is necessary to use pulp with a content of approximately 6% by weight or more based on the solid content of the raw materials (hereinafter, all expressions are based on the solid content of the raw materials). If you use a large amount of pulp,
The obtained inorganic cured product was non-flammable. It also had the disadvantage of insufficient strength, especially when absorbing water, so it was unsuitable for use as an exterior building material. .

Currently, in addition to pulp, various alternative fibers for asbestos are being considered, including inorganic fibers such as glass fiber, carbon fiber, steel fiber, and wollastonite, and organic fibers such as vinylon 7 acrylic and polyethylene. The fibers of the book are thicker than asbestos, and unlike asbestos, it does not blend well with cement, so it has not been used alone.

[Object of the invention] In view of the above-mentioned circumstances, the present invention provides a method for producing an inorganic hardened material that is nonflammable, has high strength, and can be mass-produced using a papermaking method without using asbestos. The purpose is to

[Disclosure of the Invention] As a result of repeated research, the inventors have discovered that by using pulp that has been beaten and fibrillated without being cut into short pieces, and virgin pulp that has simply been disintegrated without being fibrillated, it has been found that by using It was discovered that a hardened product with high strength could be mass-produced by the papermaking method, and this invention was thus completed.

In other words, virgin pulp from softwood, hardwood, etc.
Mill, single disc refiner.

By setting the refining conditions of a refining machine such as a double disc refiner, the fiber length can be increased to 590 microns or more (
28 mesh (on) is fibrillated while keeping it below 60% by weight to increase Schopper freeness from 40°SR to 95°.
The proportion of pulp made to SR or less is 1 to 5% by weight based on the total solid content, and the proportion of simply disintegrated virgin pulp with a Schopper freeness of 40'SR or less is 0.5 to 1.0% based on the total solid content.
If they are blended in proportions of 6% by weight, even if the amount of pulp in the solid slurry is 6% by weight or less, it is possible to make paper using the Hachinic method, and the effect of the virgin valve allows for suction. We have discovered that since water removal in each process of , making roll, and press is improved, it is possible to obtain a board that is nonflammable, has a high specific gravity, and has high strength, which is the objective of this invention. Having completed the invention, the present invention provides a method for obtaining an inorganic hardened body by curing a shaped body obtained by a papermaking method from a slurry containing cement, in which 60% by weight or more of fibers with a length of 590 microns or more are used in papermaking. The pulp whose Schopper freeness has been adjusted to 40°SR or more and 95°SR or less by fibrillation is subjected to beating treatment at a proportion of 1 to 5% by weight based on the total solid content and a Schopper freeness of 40"SR or less. Contains 0.5 to 1.0% by weight of pulp based on the total solid content, and if necessary, fillers and reinforcing fibers are added to this to achieve a concentration of 4 to 15% by weight and a filtration coefficient of 5cm.
4/s6 (The gist thereof is a method for producing an inorganic cured body characterized by using a slurry prepared as follows.

Here, the filtration coefficient is defined as follows.

That is, first, 0.5 to 1 p of the slurry, which has been adjusted to a concentrated consistency using the above-mentioned composition, is mixed with a mesh having the same mesh size as the sheave cylinder wire gauze of the Hachinik papermaking machine that is actually used in production (48 to 65 mesh). The sample is poured into a container equipped with a wire mesh, and the filtrate volume V (er&) and filtration time θ (seconds) are immediately measured until V reaches 100 d. Obtained filtration curve V
Calculate (dθ/dV) from (θ) and plot it on the vertical axis of the graph (
dθ/dV), and when V is plotted on the horizontal axis, the following equation is obtained (approximate straight line drawn by al). Calculated from this average value, ′ is the effective area S of the wire mesh.
The value divided by (cat) is taken as the filtration coefficient.

This invention will be explained in detail below.

The cement used as the binding material here is not particularly limited as long as it is hydraulic. For example, Portland cement, blast furnace cement, etc.

As the pulp, it is preferable to use softwood, broadleaf wood pulp, or lacquer craft pulp.

If waste paper such as sulfite paper or kraft paper is used in large quantities, it may cause poor curing of cement due to the influence of impurities it contains. However, waste paper often has a short fiber length in -m, so its Schopper freeness is relatively high. Therefore, it is often used in small amounts in combination with asbestos, etc., and even in this invention, the above-mentioned 40° toughness or more 95° 5Rp
Fiber length 59 when used in combination with pulp fibrillated to below 1
60ii% (hereinafter abbreviated as %) is 0 micron or larger.
).

Above, the freeness is 40°Sl? It can be used within a range where SR is kept above 95°SR.

In this invention, the Schopper freeness is 95° or more than 40°SR.
Softwood and/or hardwood pulp having 60% or more of fibers with a length of SR or less and 590 microns or more,
1 to 5% of the total solid content is used, and only disintegrated softwood and/or hardwood pulp of 40" SR or less is used in 0.5 to 1.0% of the total solid content. If the amount of pulp is less than 1%, even if other fine fillers that impair filterability are used,
It is not possible to lower the filtration coefficient to a level that allows paper making using the Hachinic method. Even if it were possible, a large amount of cement particles would escape from the mesh of the cylinder along with the water, which would not only result in poor product quality but also cause problems such as clogging of pipes during the production process, which is undesirable. In addition, if the amount of fibrillated pulp exceeds 5%, it is of course possible to make paper, but considering the preferable addition amount when adding other organic reinforcing fibers, it is difficult to achieve nonflammability. It will fail. On the other hand, if the virgin pulp with 40°SR or less is less than 0.5%, even if the paper can be made during papermaking, the dehydration properties will be poor in the subsequent process, that is, the process of dewatering the cake through felt, and the paper When rolling a cake on a king roll, the moisture content is too high, which increases the risk of the cake sticking to the roll surface or losing its shape. On the other hand, if it is used in excess of 1%, the filtration coefficient increases, the filtrate solids concentration increases, the yield of cement decreases extremely, and cake (
When press-forming a green sheet, the expansion (springback) upon release of pressure becomes large, so that only an inorganic cured product with a low specific gravity can be obtained.

When asbestos-free fiber-reinforced inorganic hardened bodies are produced by papermaking methods such as the batinic method, as mentioned above,
It is necessary to use 1 to 5% of fibrillated pulp, but even if papermaking itself is possible, if fibrillated pulp alone is used, the dehydration of the cake will be poor when placed on felt, making rolls, or during pressing. , an inorganic cured product having sufficient specific gravity cannot be obtained. On the other hand, in the manufacturing method according to the present invention, 0.5 to 1% of virgin pulp is used in combination, so dehydration from the cake is performed more efficiently during manufacturing than when only fibrillated pulp is used, so the pulp fibers This results in an inorganic hardened body with a high specific gravity in which the cement and cement are uniformly compacted.

The virgin pulp used in the method of this invention is usually disintegrated softwood pulp and/or hardwood pulp with a Schopper freeness of 40°SR or less, but this virgin pulp alone cannot be used without other fillers. Even if these are used together, papermaking is not possible. This is true even if amounts exceeding the range of 0.5 to 1% are used. This is because the filterability of the slurry is so good that cement particles escape into the filtrate, and when a beech-nick paper machine is used, there is no difference in liquid level between the inside and outside of the sieve cylinder. Therefore, Schopper freeness is 40-95°
By using the highly beaten SR pulp in combination with this virgin pulp, it becomes possible to efficiently produce an inorganic hardened material with a high specific gravity that is sufficiently filled with a matrix by the papermaking method.

Next, the fiber length of fibrillated pulp is
Although refining is performed using a refining machine such as a PFI mill, a single disc refiner or a double disc refiner, the fibers tend to be cut into short lengths at the same time as fibrillation occurs. Although it is necessary to beat the pulp to increase Schopper freeness, if the pulp is beaten too much, the fibers will be cut short and the hardened material will no longer function as a reinforcing material. for example,
Pulp fibers with a length of less than 590 microns have little reinforcing effect and are only effective in increasing Schopper freeness, so the amount of pulp fibers should be kept as low as possible (preferably kept low). The reason why the [<) rep with a length of 590 microns or more is set to be 60% or more of the total pulp amount is that if it is less than this, the water absorption rate of the cured product increases and the strength upon water absorption decreases significantly.

Next, when using a filler, it is preferable to use sepiolite, bentonite, etc. with a swelling degree of 3 times or more, or amorphous silica with an average particle size of 5 microns or less.

Here, the degree of swelling is defined as below.

By using such a filler in combination with the above-mentioned pulp and mixing it with cement and water, the filtration coefficient of the slurry can be further lowered and the slurry can be easily made into paper. In other words, by using a filler in combination, it is possible to obtain a filtration coefficient that allows papermaking even when using pulp with a low degree of beating, which not only reduces power costs during pulp beating, but also reduces product usage. This provides flexibility in that the composition can be changed not only by pulp but also by filler, depending on the purpose. Furthermore, when amorphous silica with a size of 5 microns or less is used as a filler, it reacts with cement components during curing, resulting in a product with even higher strength and higher quality.

It is not clear why the use of such a filler in combination with the above-mentioned fibrillated pulp would improve the drainage properties of the slurry and improve the cement yield, but it is speculated that the fine particles of the fibrillated pulp This is thought to be because the filler is well intertwined with the fibers, forming a mesh-like structure for filtration. The amount of filler added is preferably 1 to 10% based on the total solid content. If it exceeds 10%, there is a risk of a decrease in strength.

Next, examples of reinforcing fibers other than pulp include glass fiber,
Inorganic fibers such as carbon fiber, steel fiber, and wollastonite, or organic fibers such as polyvinyl alcohol (also referred to as Lanylon, hereinafter abbreviated as PVA), acrylic, and polyethylene can be used. Wollastonite is most preferred. It is also preferable to use PVA fibers or acrylic fibers whose width or diameter is increased in some places. Two or more types of reinforcing fibers may be used simultaneously. It is known that PVA fibers have the best bonding properties with cement among organic fibers due to their hydrophilic groups, and have excellent reinforcing effects. By using this together with fibrillated pulp and virgin pulp, it is possible to further improve the strength, particularly the impact resistance strength. The reason for this is that PVA alone has poor compatibility with cement and is easy to remove, but when used in combination with the above-mentioned pulp, the PVA fibers and the fine fibers of the fibrillated pulp intertwine well, preventing the PVA from slipping. Possibly it can be estimated. As the PVA fiber or acrylic fiber, it is preferable to use one having a thickness of 5 to 50 microns and a length of 3 to 100 ml. The content of PVA fiber or acrylic fiber is preferably 0.3 to 2%. This is because within this range, the reinforcing effect is greatest. Even if the amount of PVA or acrylic is increased beyond 2%, the strength of the cured product will hardly increase, and only the compounding cost will increase. This is 2% PVA or acrylic.
It is presumed that this is because if the content exceeds 20%, the dispersibility becomes poor. Further, if it is less than 0.3%, the reinforcing role cannot be fulfilled, and the sheet shape retention becomes insufficient, especially when uncured.

Wet spinning method as PVA or acrylic.

A cured product with even higher strength can be obtained by using fibers spun by a dry spinning method or the like, which are shaped during heat treatment so that the width or diameter of the fibers becomes larger in some places. Figure 1 is a perspective view of a morphological model of such a fiber, Figure 2 is a side view of Figure 1 viewed from the arrow A side, and Figure 3 is a side view of Figure 1 viewed from the arrow B side. It is. As shown in these figures, the fiber 1 has portions 2 which are widened at some places in the fiber axis direction. These parts 2, viewed from at least one side, have a second
As shown in the figure, the width is increased. In other words, it is normal for the fibers to be kinked in the part 2 where the fibers are pressed during heating and become wider. , it may appear flat as shown in Figure 3. However, it is not limited to what is shown in this model diagram (
, the diameter may be large when viewed from any angle. FIGS. 4 and 5 are microscopic photographs of the fiber, with FIG. 4 being a side view before molding, and FIG. 5 being a side view after heat treatment molding. As shown in FIG. 5, after the heat treatment molding, portions 2 with large widths or diameters are formed here and there.

The fiber diameter (tl) of part 2 and the original fiber diameter (t2) are 1
The relationship is 1>12. The portions 2 do not need to be regularly arranged in the fiber axis direction. The diameter of the portion 2 is preferably about 2 to 3 times the original fiber diameter (t2), but is not particularly limited to this. The number of portions 2 is preferably -20 to 100 μm in length for each fiber length of 50 to 2000 μm. This portion functions to improve adhesion at the interface with the cement matrix. Therefore, the cured product obtained by mixing PVA fibers or acrylic fibers having such parts into a cement matrix has significantly higher strength (flexural strength, impact strength, etc.) than when using ordinary PVA fibers or acrylic fibers. increases. Although the mechanism of this strength development is still unclear, it is possible to increase the surface area of the fiber without reducing its cross-sectional area.
As the adhesion area with the cement matrix increases,
It is assumed that the cause is that the convex portion makes it difficult for the fibers to come out. Since the cross-sectional area does not decrease at all, there is no decrease in the strength of the fiber itself.

The heat treatment for providing the pvA fiber or acrylic fiber with portions having a large width or diameter here and there is carried out as shown in FIG. 6, for example. A roll 3 made of metal or the like and a roll 4 made of metal or the like having many microscopic irregularities on the circumferential surface are used, and the surface temperature of the roll 4 is set to 200°C.
~300°C fineness, between both rolls 3.4 fibers 5
Pass through.

By doing so, a fiber is obtained which has portions of large width or diameter in some places. The gap (clearance) between both rolls 3 and 4 needs to be determined according to the thickness and diameter of the fibers used, but if the thickness or diameter is about 16μ, it is preferably about 8μ. Further, the distance between the convex and convex portions of the irregularities provided on the roll 4 needs to be determined depending on the desired distance between the portions having a large width or diameter.

It is well known that wollastonite is the most compatible with cement among inorganic fibers and is effective as a reinforcing material. When this wollastonite is also used in combination with ilupus (which is fibrillated like the aforementioned PVA), its effects are improved. In other words, wollastonite is entangled around the fine fibers of fibrillated pulp, improving the yield of cement and resulting in improved strength. Furthermore, the use of wollastonite has the effect of suppressing the dimensional change rate, which is a drawback of inorganic cured products mainly using pulp. The fiber length, thickness, and shape of wollastonite are not particularly limited, but it goes without saying that the fiber length, thickness, and shape of the wollastonite are preferably as large as possible. The amount of wollastonite used is preferably 2 to 15%. If it is less than 2%, the effect of adding wollastonite becomes small, and if it exceeds 15%, the reinforcing effect itself does not decrease, but the specific gravity of the cured product decreases, so the reinforcing effect as a whole becomes weaker.

A slurry is made by mixing the raw materials mentioned above and water.
The solid content concentration of this slurry needs to be 4 to 15%. Preferably it is 6 to 10%. If it is less than 4%, the efficiency of the solid content in the slurry coming up to the papermaking section (wire mesh) of the papermaking machine is poor, resulting in poor productivity.
Moreover, the solid content in the slurry tends to precipitate, making it impossible to obtain an inorganic cured product having the intended composition. On the other hand, 15
If it exceeds %, the thickness of the cake formed becomes uneven, and it tends to be difficult to obtain a homogeneous cured product.

It is necessary to adjust the filtration coefficient of the slurry to less than 5 c[n'/sec, which is an absolute condition for papermaking using a no-check method or the like. Turn to this invention, this 5cm'
/sec, the amount of pulp and inorganic filler as mentioned above (
This can be achieved by adjusting the

A slurry is made with the above-mentioned composition, and is made into paper using a paper making machine such as a /S check paper making machine, and then laminated to form a shaped body of an appropriate thickness. By curing this shaped body, a Let' cured body is obtained.

Next, examples will be described together with comparative examples.

[Examples and Comparative Examples] The raw materials shown in Table 1 were used, and the Hachinik method using a 1-chien papermaking machine was used to produce actual) IH to 12.
Inorganic cured bodies of Comparative Examples 1 to 6 were made. Table 1 also shows the manufacturing conditions and the results of the test G on which the obtained cured product was subjected.

In addition, slurry filtration (all series numbers are 5 cm'/s
It was set as ec.

In the table, in the evaluation of frost damage resistance, ◎ is good, ○ is fair,
× indicates unsuitability. In addition, NUKP is unexposed coniferous kraft resin (see below) Table 1 shows that the uncured products obtained in Examples 1 to 12 are the same as those obtained in Comparative Examples 1 to 6. It can be seen that the performance is superior in comparison.

〔Effect of the invention〕

Since the method of this invention is configured as described above,
Even without using asbestos, a nonflammable and highly strong inorganic cured product can be mass-produced by the papermaking method.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a morphological model of PVA fiber or acrylic fiber with increased width in some places, Figure 2
The figure is a side view of Fig. 1 seen from the arrow A side, Fig. 3 is a side view of Fig. 1 seen from the arrow B side, and Figs. 4 and 5 are P
FIG. 4 is a side view of VA fiber or acrylic fiber before molding, FIG. 5 is a side view after heat treatment molding, and FIG. 6 is an explanatory diagram of heat treatment. Agent: Patent Attorney Takehiko Matsumoto Figure 2 Figure 3 Figure 5

Claims (7)

[Claims] (1) In a method for obtaining an inorganic hardened body by curing a shaped body obtained by a papermaking method from a slurry containing cement, in papermaking, the fiber length is 590 microns or more and the fiber length is 60% by weight or more, and the Schopper freeness is 40% by fibrillation. Pulp adjusted to 95°SR or above with a ratio of 1 to 5% by weight based on the total solid content, and a Schopper freeness of 40°
Pulp that is not beaten to a level below SR is 0 based on the total solid content.
．． 5-1. OM amount% of each, and if necessary, filler and reinforcing fibers are added to this to make the concentration 4 to 1.
A method for producing an inorganic cured body, comprising using a slurry having a filtration coefficient of 5% by weight and a filtration coefficient of 5cm47sec or less. (2) The method for producing an inorganic cured product according to claim 1, wherein the pulp is a pulp of softwood and/or hardwood. (3) The filler is at least one selected from the group consisting of sepiolite, bentoite, and quality or amorphous silica with an average particle size of 5 microns or less, and is 1 to 10% by weight based on the total solid content. % by weight of the inorganic cured body according to claim 1 or 2. (4) The reinforcing fiber has a thickness of 5 to 50μ and a length of 3 to 10m.
The method for producing an inorganic cured product according to any one of claims 1 to 3, wherein the vinylon fiber is contained in an amount of 0.3 to 2% by weight based on the total solid content. (5) The method for producing an inorganic cured product according to any one of claims 1 to 4, wherein the reinforcing fibers are Hinilon fibers having portions with increased width or diameter here and there. (6) The reinforcing fiber has a thickness of 5 to 50μ and a length of 3 to 10mm.
The method for producing an inorganic cured product according to any one of claims 1 to 3, wherein the inorganic cured product is acrylic fiber containing 1.3 to 2% by weight based on the total solid content. (7) The method for producing an inorganic cured product according to any one of claims 1 to 3 and 6, wherein the reinforcing fibers are acrylic fibers having portions with increased width or diameter in some places. . (Claim 1 in which the 81 reinforcing fiber is wollastonite and is contained in an amount of 2 to 15% by weight based on the total solid content)
A method for producing an inorganic cured body according to any one of Items 1 to 3.