JPH0616464A - Calciumsilicate molded body - Google Patents

Abstract

PURPOSE:To obtain a calciumsilicate molded body which has a light weight and also a practical flexural strength. CONSTITUTION:This calciumsilicate molded body is constituted of a structure wherein nearly spherical secondary particles formed by three-dimensionally Tobermorite crystals or a small quantity of other calciumsilicate crystals with them, are mutually connected, and the spherical secondary particles have 10-120mum of the outer diameter before the molding and whose hollow rate and the free sedimentation molded body density are <=30% and <=0.12g/cm<3>, respectively.

Description

Detailed Description of the Invention

The present invention relates to a calcium silicate compact. Calcium silicate compacts are industrially applied to various fields such as refractories, fireproof heat insulating materials, adsorbents, building materials, etc. These have high specific strength, which is characteristic of calcium silicate compacts, and fire resistance. It is an inorganic material that is expected to develop in various fields due to its high price, heat insulating property, light weight, high dielectric property and the like. It is considered that the main point of the characteristic property is the structure of the formed body composed of calcium silicate crystals. The inventors of the present invention have been researching calcium silicate from the above viewpoints, and when the calcium silicate crystals have an extremely unique secondary agglomeration structure in this research, they are lightweight and have high strength. The present invention was completed based on this finding (Patent No. 818975). The calcium silicate secondary agglomerated particles according to this patent are almost spherical secondary particles formed by three-dimensionally entangled calcium silicate crystals, the outer diameter of which is 10 to 150 μm, and the surface thereof is Had a structure in which a large number of whiskers based on calcium silicate crystals were projected, and a calcium silicate compact obtained from this had a low density and high strength. Furthermore, the present inventors have completed various improved new inventions based on this patent, one of which is Japanese Patent Publication No. 56-4010.
There is an invention of No. 9. The present invention relates to a tobermorite crystal compact. The present inventors further researched the relationship between the structure of the calcium silicate secondary particles and the calcium silicate compact, and as a result, succeeded in developing spherical secondary particles having a peculiar structure composed of tobermorite crystals and It was found that the produced tobermorite molded product had extremely excellent physical properties, and the present invention was completed here. That is, the present invention provides a molded article formed by interconnecting tobermorite crystals or secondary spherical particles having a small amount of other calcium silicate crystals entangled three-dimensionally with each other. Before molding, the spherical secondary particles have an outer diameter of 10 to 120 μm, a hollow ratio of 30% or less, and a spontaneous sedimentation molded body density of 0.12 g / cm ³ or less. The present invention relates to a calcium silicate compact. In the present specification, the term "spherical" includes not only a spherical shape but also an elliptical spherical shape, and these spherical and elliptical spherical shapes also include those in which at least a part of the surface thereof is uneven. According to the study by the present inventors, the inside of the tobermorite spherical secondary particles constituting the above-mentioned formed body of the present invention is rough or hollow before forming, and the density of the spontaneous sedimentation formed body is also compared. The compacts that are relatively small and fairly lightweight are manufactured by the conventional Japanese Patent Publication No. 56-40109.
It was clarified that it was superior to the molded article of No. 1 in the following points. (A) A lightweight molded product of about 0.1 g / cm ³ and having a practical bending strength of 3 kg / cm ² or more. (B) The degree of preferential orientation is particularly large at a compact density of 0.3 g / cm ³ or more. The present invention has been completed based on the above new facts. The molded article of the present invention is composed of spherical secondary particles composed of a tobermorite crystal alone or a mixture thereof with a small amount of another calcium silicate crystal, for example, zonotolite crystal, connected in a mutually compressed and deformed state. . The specific spherical secondary particles constituting the molded body of the present invention have an outer diameter of 10 to 120 μm before molding, and the inside thereof is coarse to 30%.
It has a secondary aggregation structure having the following hollow ratio. This is clear from, for example, the result of microscopic observation of the secondary particles before molding shown in Example 1 of the present invention.
That is, the above-mentioned secondary particles are an optical micrograph (Fig. 1, magnification 1
00 times) to a spherical body with an outer diameter of about 10 to 120 μ
It can be seen that the average particle size is 38 μm. A surfactant was added to and mixed with the slurry in which the secondary particles were dispersed in water, and the mixture was allowed to stand for 48 hours and spontaneously sedimented.
A part of the spontaneously settled molded product obtained by drying at 48 ° C. for 48 hours is cut out, fixed with Canadian balsam, polished, and then the above Canadian balsam is removed with xylene to obtain a polished sample. Observation of this sample with a scanning electron microscope reveals that the tobermorite crystals are coarsely aggregated to form spherical secondary particles, as shown in FIG. Further, when these secondary particles are dispersed and observed with an electron microscope, plate-like crystals having a length of 0.1 to 10 μm and a width of 0.1 to 2 μm and a length of 0.1 to 10 μm and a width of 0. 05-0.5
Needle-like crystals of μm are observed. <Method of measuring outer diameter of secondary particles> 100 photographed by reflected light
The directional diameter was measured from the optical micrograph of the spherical secondary particles mainly composed of doubled tobermorite crystals, and the range of the particle diameter and the average particle diameter (median diameter) were obtained. The spherical secondary particles of the present invention are characterized in that the breaking load of each particle is 100 mg or less. The above-mentioned breaking load means a load when a crack is generated in at least a part of the spherical shell of the secondary particles of the calcium silicate crystal when the load is applied to the spherical secondary particles, and the breaking load is, for example, 10 to 100.
The term “mg” means that when a load is applied to the secondary particles, at least one of spherical shells of the secondary particles is applied when the secondary particles are subjected to a constant load of 10 to 100 mg. When the breaking load is 1000 mg, it means that at least a part of the spherical shell of the secondary particles is cracked when a load of 1000 mg is applied. <Measurement Method of Breaking Load> The three secondary particles are placed on a slide glass in an equilateral triangle shape, a cover glass is placed on the slide glass, and the load is applied on the cover glass to observe with a 600 × optical microscope. It is measured by observing whether or not a crack occurs in a part of the spherical shell of the secondary particle, and is expressed by a load when the crack occurs. Other major characteristics of the spherical secondary particles are: (a) The inside is coarse or hollow, and the hollow ratio is 30%.
The following means that the hollow ratio is measured by the following method. A part of the spontaneous sedimentation molded body was cut out, fixed with Canadian balsam (manufactured by Yoneyama Pharmaceutical Co., Ltd.), and then polished, and then the Canadian balsam was removed with xylene to obtain a polished sample. This sample was photographed with a scanning electron microscope, the radius (r) and the radius (r ') of the hollow portion were measured from the cross section of the spherical secondary particles, and the hollow ratio was obtained from the following formula.

[Chemical 1] The hollow ratio of 30% or less indicates that the hollow part is not particularly large even if the inside of the spherical secondary particles is hollow. Moreover, the case where small hollow portions are present everywhere and the so-called inside is rough is also included. The inside of the spherical secondary particles shown in FIG. 3 is coarse and the hollow ratio is 0%, and the hollow ratio of the spherical secondary particles shown in FIG. 4 is 0 to 25%.
Is. For example, the hollow secondary particles composed of wollastonite group calcium silicate crystals described in the examples of JP-A-53-146997 have a hollowness of 60% or more, which is a structure fundamentally different from that of the spherical secondary particles of the present invention. have. (B) It has a characteristic that the density of the spontaneous sedimentation molding is 0.12 g / cm ³ or less, preferably 0.10 g / cm ³ or less.
The density of the spontaneous sedimentation molded product was measured by the following method. Three
To a 00 cc tall beaker, 200 cc of the slurry and 0.4 cc of a nonionic and anionic surfactant (Granup NF-50, Sanyo Kasei Co., concentration 20%) were added and mixed, and then 48
Allow it to stand for a period of time to allow it to settle at 100 ° C for 48 hours.
It was dried for a period of time to obtain a naturally precipitated molded body. The volume and weight of this were measured to determine the density. The fact that the density of this spontaneously-precipitated compact is small means that the spherical secondary particles themselves are considerably light weight, and from this secondary particle, a compact having a density of about 0.1 g / cm ³ and having practical strength can be produced. Shows. For example, the spherical secondary particles of the tobermorite crystals described in JP-B-56-40109 have a high spontaneous sedimentation compact density, and therefore the density of 0.1 g / cm ³ from the known secondary particles of the tobermorite crystals. It is not possible to produce molded bodies of a certain degree. Further, the preferred spherical secondary particles of the present invention have an average apparent density of 0.14 to 0.21 g / c before molding.
m ³ Especially, it is mainly in the range of 0.16 to 0.20 g / cm ³ . That is, the secondary particles are themselves lightweight. The average apparent density is measured by the following method. <Measurement Method of Average Apparent Density> The slurry of the tobermorite crystal was replaced with water in the slurry by acetone to obtain 90
Dry at 24 ° C. for 24 hours to make spherical secondary particles into powder without damage. This powder Wg is measured and placed in a beaker. Next, use a buret to impregnate the spherical secondary particles with water, and read the amount of water just when the spherical secondary particles were impregnated with water (when the viscosity of the spherical secondary particles suddenly increased) as Vml. To do. From this measurement, the average apparent density (ρ) of the spherical secondary particles was calculated by the following formula.

[Chemical 2] However, ρt is the true specific gravity of Tobermorite, which is 2.576.
Is. The molded body of the present invention is constituted by connecting such spherical secondary particles to each other in a shape compressed by the pressure during molding. In the molded article of the present invention, the shape of the spherical secondary particles becomes flat in the compression direction as the pressure at the time of molding increases, in other words, as the density of the molded article increases.
However, when the density of the molded product was 0.3 g / cm ³ or less, a part of the molded product of the present invention was cut out, fixed with Canadian balsam, and after polishing, the Canadian balsam was removed with xylene to obtain the molded product. The presence of spherical secondary particles can be confirmed by observing the polished surface with a scanning electron microscope. For example, FIG. 5 (magnification: 600 times) showing a scanning electron micrograph of a polished surface of a molded body having a density of 0.201 g / cm ³ shown in Example 2 of the present invention.
Clearly shows the existence of spherical secondary particles. However, as the density of the molded body increases beyond 0.3 g / cm ³ , the existence of spherical secondary particles becomes difficult to be clearly identified by an electron microscope, and as the density increases, the flattening of the flattened It gets even more intense. This fact indicates that the tobermorite crystals are preferentially oriented, especially when the density of the compact is 0.3.
It is shown that the preferred orientation of the crystal becomes particularly large at 0 g / cm ³ or more. The preferential orientation satisfies a certain relationship represented by the following equation, where the degree of orientation is P and the density is x. P ≧ ax−b (however, 0.3 ≦ x. Both a and b change depending on the addition amount, and when there is no additive, a is 20 and b.
Indicates 3.) The degree of preferential orientation is measured by the following method. A part of the compact is sampled and finely pulverized to make a non-oriented powder sample, while another sample having a plane perpendicular to the press direction is made from the compact (oriented sample), and then two samples of tobermorite The X-ray diffraction intensities of the (002) and (220) planes of the crystal are measured, respectively. The preferred orientation degree (P) is

[Chemical 3] Is given by Where I (002) and I
(220) is the diffraction intensity of the non-oriented powder sample, I '(00
2) and I '(220) are the diffraction intensity of the oriented sample. The molded product of the present invention is characterized in that the above-mentioned degree of preferential orientation is very large. As described above, the orientation is the degree to which the tobermorite crystals present in the compact are arranged in a certain direction due to the pressure during molding, and only in the compact composed of spherical secondary particles interconnected. Although it is a peculiarity to be recognized, its preferential orientation is particularly dependent on the number of secondary particles per unit area that are subject to compressive deformation due to pressure during molding and the packing density of crystals on the surface of each secondary particle. different. The molded product of the present invention has a characteristic that the preferential orientation is remarkably large at 0.3 g / cm ³ or more, as compared with the conventionally known molded product of the tobermorite spherical secondary particles. The molded product of the invention has a low density (that is, a large number per unit area) and an internal hollow ratio of 3
Since it is composed of 0% or less of hollow or coarse spherical secondary particles, the degree of preferential orientation is remarkably large at the same density. As described above, the molded body of the present invention is composed of tobermorite crystals, and these crystals form the above-mentioned unique spherical secondary particles, and these secondary particles are connected to each other. Compared with conventional tobermorite moldings, it has extremely low density and practical strength. The molded article of the present invention will be described below by its manufacturing method. The molded body of the present invention is, for example, spherical secondary particles before molding, that is, spherical secondary particles formed by three-dimensionally entangled tobermorite crystals, and the outer diameter thereof is about 10 to about 120.
It can be produced by molding and drying an aqueous slurry in which spherical secondary particles having a mean apparent density of 0.14 to 1.21 g / cm ³ and a coarse or hollow interior are dispersed in water. The desired characteristics are exhibited by being produced from the aqueous slurry as described above. That is, when the above slurry is molded, water existing between the secondary particles easily escapes from between the particles, and the molding pressure uniformly acts on the entire slurry. The water present in the hollow or coarse portions inside the particles resists the above-mentioned pressure and is compressed and connected to each other while maintaining the particle shape without destroying it. Following this decrease in interparticle water, the water inside the particles is gradually discharged. Therefore, if the molded product obtained after the dehydration molding is dried, the water inside the particles is completely discharged and thus a molded product having a desired low density and high strength can be obtained. The ratio of water to solid content of the aqueous slurry used in the above method is not particularly limited, but is preferably 3 times (weight) or more, preferably about 5 to 30 times (weight). Further, this aqueous slurry may contain various additives as required. As a result, the tobermorite molded product of the present invention, which is a composite of various additives, can be obtained. Here, as the additive, for example, asbestos, rock wool, glass fiber, ceramic fiber, carbon fiber, inorganic fiber such as metal fiber, animal fiber such as pulp, cotton, hemp, wool, wood fiber, rayon, polyacrylonitrile, polypropylene Examples of the reinforcing material include organic synthetic fibers such as polyamide and polyester, and these fiber materials can further improve the mechanical strength, hardness, and other characteristics of the molded body, and further improve the moldability. In particular, the fibrous material serves to increase the mechanical strength of the shaped body. In addition, various clays can be used for improving heat resistance, and further, cements, gypsum, colloidal silica, alumina sol for reducing or eliminating shrinkage at the time of drying after molding or for increasing the surface strength of the molded body. Alternatively, a phosphoric acid-based or water glass-based binder or the like may be added. It is also possible to interpose a wire net, a metal streak or the like. In the present invention, examples of the molding means for molding the aqueous slurry into a molded product include a natural sedimentation method, a mold injection method, a press dehydration molding method, a centrifugal molding method and the like. Further, the tobermorite molded product manufactured as described above is fired to transform the tobermorite crystals constituting the same into β-wollastonite crystals, whereby a β-wollastonite molded product can be obtained. Tobermorite is β
-It is easily performed under a temperature condition equal to or higher than the temperature at which it transforms into wollastonite. Generally, it may be heated at 800 ° C. or higher, for example, 850 ° C. for about 3 hours. Further, since the molded body composed of the β-wollastonite crystal requires heating, the additive material added to the molded body is not substantially changed by heating such as the above-mentioned inorganic fibers and clay binder. Must be inorganic. Thus, the crystals constituting the molded body are transformed into β-wollastonite crystals, and a molded body in which various inorganic additives are compounded is obtained as necessary. The aqueous slurry of spherical secondary particles for producing the above-mentioned molded article of the present invention can be easily produced, for example, by the following method.
That is, lime milk having a sedimentation volume of 5 ml or more and silicic acid mainly containing crystalline are mixed so that the amount of water to solid content is 15 times (weight) or more to form a raw material slurry, which is heated and stirred under pressure. A hydrothermal synthesis reaction can be performed to obtain an aqueous slurry of spherical secondary particles composed of tobermorite crystals. At this time, the sedimentation volume of 5 ml or more means that 50 ml of lime milk prepared by increasing the solid content ratio of water to lime to 120 times has a diameter of 1.3.
The volume of the lime settled after being placed in a cylindrical container having a volume of 50 cm or more and having a volume of 50 ml or more and allowed to stand for 20 minutes is shown in ml. The large settling volume means that lime is well dispersed in water and in a stable state, that is, it is composed of extremely fine particles, and thus exhibits high reactivity. Since the molded product of the present invention is manufactured from the spherical secondary particles having the above-mentioned characteristics by using the highly reactive lime as described above, it has low density and sufficient practical strength. . In the above production method, it is essential to use lime milk having a sedimentation volume of 5 ml or more and having extremely excellent dispersion stability. If lime milk whose sedimentation volume does not reach 5 ml is used, the above-mentioned unique spherical secondary particles cannot be obtained. The method itself for producing lime milk having a sedimentation volume of 5 ml or more used is secondary and is not particularly limited. The settling volume of this lime milk depends on the limestone itself as a raw material, the firing temperature during lime production, the amount of water when slaked lime into water, the temperature at that time, the stirring conditions at that time, etc. Although it is greatly affected by the temperature and stirring conditions at the time of medium digestion, it is not possible to obtain the desired lime milk having a sedimentation volume of 5 ml or more by the usual method for producing lime milk. Thus, for lime milk having a sedimentation volume of 5 ml or more, typically, the ratio of water to lime content (solid content) is 5 times (weight) or more, and the mixture may be stirred at a high temperature or at high speed, preferably at a temperature of 60 ° C. or more. For example, the desired lime milk can be obtained by vigorous stirring with a homomixer. The stirring speed and stirring strength can generally be lowered by increasing the temperature and time during stirring. Various types of stirrers are used, and those with or without a baffle plate can be used. Various kinds of lime can be used as a lime raw material used for producing lime milk, and for example, quick lime and slaked lime are suitable because they can increase the sedimentation volume most.
A crystalline silicic acid raw material is used as the silicic acid raw material used for producing the aqueous slurry of spherical secondary particles in the present invention. Examples thereof include quartzite, quartz, sandstone quartzite, cohesive quartzite, recrystallized quartzite, composite quartzite, silica sand, and quartzite. These silicic acid raw materials generally have an average particle size of 30μ.
m is preferably 1 to 20 μm or less. The above-mentioned silicic acid raw material may further contain amorphous silicic acid as long as it contains a crystalline silicic acid raw material as a main component, and the amorphous silicic acid is converted into crystalline silicic acid in an amount of 50% (by weight) or less. It can also be mixed and used. As the silicic acid raw material, A
It is possible to use a material having a considerably high l ₂ O ₃ content, and it is usually sufficient if the content is about 5% or less. The mixing molar ratio of lime and silicic acid is 0.70 to 0.95, which is a desirable molar ratio for producing tobermorite or other crystals of calcium silicate. The lime milk and the silicic acid raw material are mixed to prepare a raw material slurry with a water-to-solid content ratio of 15 times (weight) or more, and this is then subjected to a hydrothermal synthesis reaction while heating and stirring under pressure. The reaction conditions such as pressure, temperature and stirring speed at this time are appropriately determined depending on the reaction vessel used for the reaction, the stirrer, the type of reaction product and the like. The temperature and pressure in the hydrothermal reaction are usually 5 kg / cm ²
That is all. The time can be shortened by increasing the temperature and pressure, but it is economically preferable that the reaction time is short, but considering the safety during operation, it is preferably 10 hours or less. An example of preferable conditions is, for example, a saturated steam pressure of 12 k.
It is about 3 hours at g / cm ² and about 6 hours at 8 kg / cm ² . The stirring in this hydrothermal synthesis reaction is appropriately determined according to the raw materials used, the reaction vessel and the reaction conditions. For example, when a sliding type stirring blade is used in a reaction vessel having a diameter of 150 mm and a capacity of 3 l, silica stone powder having a sedimentation volume of lime milk of 30 ml and an average particle diameter of about 5 μm is used as a raw material slurry at a water ratio of 24 times. At a stirring speed of 100 r. p. It is about m. Examples of the stirring operation include various stirring operations of rotating the reactor itself, vibrating it, and injecting a gas or a liquid. The hydrothermal reaction may be a batch type reaction or a continuous reaction. When performing the continuous reaction, the raw material slurry is continuously pressed into the reaction vessel and the synthetic slurry (calcium silicate crystal slurry) after the reaction is discharged under normal pressure. Good. Secondary particles need to be kept intact during this discharge. Alternatively, the water ratio of the raw material slurry may be reduced to cause the reaction in the reaction vessel, and after the reaction, a predetermined amount of water may be pressed and discharged. When synthesizing the calcium silicate, a reaction accelerator, a catalyst, a suspending agent and the like can be appropriately added to the raw material slurry. Examples thereof include wollastonite and calcium silicate hydrate, as well as various salts of alkali and alkali metals such as caustic soda and caustic potash. The addition amount of the above-mentioned additive is not particularly limited as long as the intended spherical secondary particles of calcium silicate crystals can be obtained, but wollastonite and the like are usually preferably up to about 30% by weight. By hydrothermal synthesis reaction from a raw material slurry prepared from the specific lime milk and a silicic acid raw material, in obtaining an aqueous slurry of spherical secondary particles for producing the molded body of the present invention, the raw material slurry, asbestos, Inorganic fibers such as alkali resistant glass fibers, ceramic fibers, rock wool, and organic fibers such as alkali resistant pulp can be further added. By this operation, an aqueous slurry in which spherical secondary particles and inorganic fibers are uniformly dispersed in water is obtained. This aqueous slurry differs from the one obtained by adding inorganic fibers to an aqueous slurry of spherical secondary particles obtained by subjecting the raw material slurry to a hydrothermal synthesis reaction in the following points. That is, in the former case, since the silicic acid raw material and the lime raw material in the raw material slurry are crystallized on the inorganic fibers to form spherical secondary particles, spherical secondary particles bonded to the inorganic fibers are easily generated. On the other hand, in the latter, since the inorganic fiber is added after the crystallization and the formation of the spherical secondary particles, the inorganic fiber and the spherical secondary particles are not bonded in principle. Due to such a difference, the mechanical strength of the molded product of the present invention obtained from this kind of aqueous slurry tends to be slightly higher in the former case. Examples for clarifying the features of the present invention will be shown below. In the following examples, parts or% means parts by weight or% by weight unless otherwise specified. Example 1 42.25 parts of quicklime (CaO 95.0%) was hydrated in 507 parts of hot water at 80 ° C. and dispersed in water with a homomixer for 3 minutes to obtain a lime milk having a sedimentation volume of 18.9 ml. there were. Silica powder (S with an average particle size of about 9 μm) (S
iO ₂ 97.37%, Al ₂ O ₃ 0.99%) 5
3.21 parts were added and the total amount of water was mixed to be 22 times the solid content by weight to obtain a raw material slurry, which was saturated water vapor pressure 12 kg / cm ² , temperature 191 ° C. and volume 3000 c.
c, rotation speed of 174 r.m. in an autoclave having an inner diameter of 15 cm.
p. The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. 100% of this crystal slurry
It was confirmed that the crystals were tobermorite when dried at 24 ° C. for 24 hours and analyzed by X-ray diffraction. This crystal slurry was dried on a slide glass and observed with an optical microscope.
As shown in (4), spherical secondary particles having an average outer diameter of 38 μm were recognized. Further, by adding and mixing a surfactant to the slurry,
Allow it to stand for 48 hours to let it settle at room temperature and then add it to 100 ° C for 4 hours.
A part of the spontaneous precipitation molded body obtained by drying for 8 hours was cut out, fixed with Canadian balsam, and then polished, and then the above Canadian balsam was removed with xylene to obtain a polished sample. When this sample was observed with a scanning electron microscope, it was found that the tobermorite crystals coarsely aggregated to form spherical secondary particles as shown in FIG. When these secondary particles are dispersed and observed with an electron microscope, plate-like crystals having a length of 0.1 to 10 μm and a width of 0.1 to 2 μm and a length of 0.1 to 10 μm and a width of 0. 05-0.5 μm
Needle crystals were observed. The characteristics of the secondary particles are as follows:
It was as shown in the table.

[Table 1] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 2.

[Table 2] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the obtained molded product are shown in Table 3.

[Table 3] Example 2 41.42 parts of quicklime (CaO 95.1%) was dissolved in 497 parts of hot water at 80 ° C. and dispersed in water with a homomixer for 5 minutes to obtain a lime milk having a sedimentation volume of 17.5 ml. there were. Silica powder (SiO ₂ 94.03%, Al ₂ O ₃ 2.37%) with an average particle size of about 8.5 μm is added to the lime milk.
54.04 parts were added and the total amount of water was mixed to be 22 times the solid content by weight to obtain a raw material slurry, which was saturated water vapor pressure 12 kg / cm ² , temperature 191 ° C. and volume 3000.
Rotation speed 174 in an autoclave with cc and inner diameter of 15 cm
r. p. The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. 1 of this crystal slurry
When it was dried at 00 ° C. for 24 hours and analyzed by X-ray diffraction, it was confirmed to be tobermorite crystals. When this crystal slurry was dried on a slide glass and observed with an optical microscope, spherical secondary particles having an average outer diameter of 52 μm were recognized. In addition, a surfactant was added to the slurry and mixed, and the mixture was allowed to stand for 48 hours,
A portion of the natural sedimentation molded body obtained by allowing it to spontaneously sediment and then drying it at 100 ° C. for 48 hours was cut out, fixed with Canadian balsam, and then ground to remove the Canadian balsam with xylene. A polished sample was obtained. When this sample was observed with a scanning electron microscope, it was found that the tobermorite crystals were coarsely aggregated and spherical secondary particles having a hollow inside were formed as shown in FIG. When these secondary particles are dispersed and observed by an electron microscope, plate-like crystals having a length of 0.1 to 10 μm and a width of 0.1 to 2 μm and a plate crystal having a length of 0.1 to 10 μm and a width of 0.05 to 0.5 μm. Needle-like crystals were observed. The characteristics of the secondary particles are as shown in Table 4.

[Table 4] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 5.

[Table 5] Further, a part of the molded body (Sample No. 1) shown in Table 5 was cut out, fixed with Canadian balsam, then polished, and then the polished sample obtained by removing the Canadian balsam with xylene was used as a scanning electron. Observation with a microscope reveals that the spherical secondary particles are interconnected as shown in FIG. Then, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner, and then at 2O 0 C for 2 hours.
It was dried for 0 hours to obtain a molded body. The physical properties of the obtained molded product are as shown in Table 6.

[Table 6] Example 3 45.56 parts of quicklime (CaO 95.6%) was dissolved in 547 parts of hot water at 80 ° C. and dispersed in water with a homomixer for 6 minutes to obtain a lime milk having a sedimentation volume of 28.0 ml. there were. Silica powder (SiO ₂ 94.03%, Al ₂ O ₃ 2.37%) with an average particle size of about 8.5 μm is added to the lime milk.
A raw material slurry was obtained by adding 59.44 parts and mixing the total amount of water to be 20 times the solid content, and saturating a steam pressure of 8 kg / cm ^{2 at} a temperature of 175 ° C. and a volume of 3000 c.
c, rotation speed of 174 r.m. in an autoclave having an inner diameter of 15 cm.
p. The hydrothermal synthesis reaction was carried out for 6 hours while rotating the stirring blade at m to obtain a crystal slurry. 100% of this crystal slurry
It was confirmed that the crystals were tobermorite when dried at 24 ° C. for 24 hours and analyzed by X-ray diffraction. When this crystal slurry was dried on a slide glass and observed with an optical microscope, spherical secondary particles having an average outer diameter of 45 μm were recognized. Further, a surfactant was added to the slurry and mixed, allowed to stand for 48 hours to spontaneously settle, and then dried at 100 ° C. for 48 hours to cut out a part of the naturally settled molded body, which was fixed with Canadian balsam. Then, after polishing this, the above Canadian balsam was removed with xylene to obtain a polishing sample. Observation of this sample with a scanning electron microscope revealed that the tobermorite crystals aggregated coarsely to form spherical secondary particles. When these secondary particles are dispersed and observed by an electron microscope, plate-like crystals having a length of 0.1 to 10 μm and a width of 0.1 to 2 μm and a plate crystal having a length of 0.1 to 10 μm and a width of 0.05 to 0.5 μm. Needle-like crystals were observed. The properties of the secondary particles are shown in Table 7.

[Table 7] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 8.

[Table 8] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the obtained molded product are as shown in Table 9.

[Table 9] Example 4 45.83 parts of quicklime (CaO 95.0%) was dissolved in 550 parts of hot water at 80 ° C. and dispersed in water for 7 minutes with a homomixer to obtain a lime milk having a sedimentation volume of 31.6 ml. there were. Silica powder (SiO ₂ 95.01%, Al ₂ O ₃ 3.27%) having an average particle diameter of about 1.6 μm is added to the lime milk.
59.17 parts were added and the total amount of water was mixed to be 20 times the weight of the solid content to obtain a raw material slurry, which was saturated water vapor pressure 12 kg / cm ² , temperature 191 ° C. and volume 3000.
Rotation speed of 112 in autoclave with cc and inner diameter of 15 cm
r. p. The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. 1 of this crystal slurry
When it was dried at 00 ° C. for 24 hours and analyzed by X-ray diffraction, it was confirmed to be tobermorite crystals. When this crystal slurry was dried on a slide glass and observed with an optical microscope, spherical secondary particles having an average outer diameter of 24 μm were recognized. In addition, a surfactant was added to the slurry and mixed, and the mixture was allowed to stand for 48 hours,
A portion of the natural sedimentation molded body obtained by allowing it to spontaneously sediment and then drying it at 100 ° C. for 48 hours was cut out, fixed with Canadian balsam, and then ground to remove the Canadian balsam with xylene. A polished sample was obtained. When this sample was observed with a scanning electron microscope, it was found that the tobermorite crystals were coarsely aggregated and spherical secondary particles having a hollow inside were formed. When these secondary particles are dispersed and observed with an electron microscope, the length is 0.1 to 10 μm,
A plate crystal having a width of 0.1 to 2 μm and a length of 0.1 to 10 μm,
Needle-like crystals with a width of 0.05 to 0.5 μm were observed. Table 10 shows the respective properties of the secondary particles.

[Table 10] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 11.

[Table 11] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the obtained molded product are as shown in Table 12.

[Table 12] Example 5 42.23 parts of quick lime (CaO 95.0%) was dissolved in 507 parts of hot water at 80 ° C. and dispersed in water for 6 minutes with a homomixer to obtain a lime milk having a sedimentation volume of 26.0 ml. there were. Silica powder (SiO ₂ 95.01%, Al ₂ O ₃ 3.27%) having an average particle diameter of about 1.6 μm is added to the lime milk.
A raw material slurry was obtained by adding 53.23 parts and mixing the total amount of water to be 20 times the solid content by weight, and saturating a steam pressure of 12 kg / cm ^{2 at} a temperature of 191 ° C. and a volume of 3000.
Rotation speed of 112 in autoclave with cc and inner diameter of 15 cm
r. p. The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. 1 of this crystal slurry
When dried at 00 ° C. for 24 hours and subjected to X-ray diffraction analysis, it was confirmed that the tobermorite crystals were mixed with a small amount of zonotolite crystals. When this crystal slurry was dried on a slide glass and observed with an optical microscope, spherical secondary particles having an average outer diameter of 31 μm were recognized. Further, a surfactant was added to the slurry and mixed, allowed to stand for 48 hours to spontaneously settle, and then dried at 100 ° C. for 48 hours to cut out a part of the naturally settled molded body, which was fixed with Canadian balsam. Then, after polishing this, the above Canadian balsam was removed with xylene to obtain a polishing sample. When this sample was observed with a scanning electron microscope, it was found that the tobermorite crystals and a small amount of zonotolite crystals were roughly aggregated and that secondary particles having a hollow inside were formed. The properties of the secondary particles are as shown in Table 13.

[Table 13] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 14.

[Table 14] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the obtained molded product are as shown in Table 15.

[Table 15] Example 6 42.25 parts of quicklime (CaO 95.0%) was hydrated in 507 parts of hot water at 80 ° C. and dispersed in water for 2 minutes with a homomixer to obtain a lime milk having a sedimentation volume of 8.1 ml. there were. Silica powder (Si having an average particle size of about 9 μm) (Si
O ₂ 97.37%, Al ₂ O ₃ 0.99%) 53.
21 parts was added and the total amount of water was mixed to be 22 times the solid content by weight to obtain a raw material slurry, which was saturated water vapor pressure 12 kg / cm ² , temperature 191 ° C., volume 3000 cc,
Rotation speed of 174 r.m. in autoclave with inner diameter of 15 cm. p.
The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. When this crystal slurry was dried at 100 ° C. for 24 hours and subjected to X-ray diffraction analysis, it was confirmed to be tobermorite crystals. When this crystal slurry was dried on a slide glass and observed by an optical microscope, spherical secondary particles having an average outer diameter of 47 μm were recognized. Further, a surfactant was added to the slurry and mixed, allowed to stand for 48 hours to spontaneously settle, and then dried at 100 ° C. for 48 hours to cut out a part of the naturally settled molded body, which was fixed with Canadian balsam. Then, after polishing this, the above Canadian balsam was removed with xylene to obtain a polishing sample. Observation of this sample with a scanning electron microscope revealed that the tobermorite crystals aggregated coarsely to form spherical secondary particles. When these secondary particles are dispersed and observed by an electron microscope, plate-like crystals having a length of 0.1 to 10 μm and a width of 0.1 to 2 μm and a plate crystal having a length of 0.1 to 10 μm and a width of 0.05 to 0.5 μm. Needle-like crystals were observed. The characteristics of the secondary particles are as shown in Table 16.

[Table 16] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 17.

[Table 17] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the resulting molded product are shown in Table 18.

[Table 18] Comparative Example 1 The sedimentation volume of lime milk obtained by soaking 42.25 parts of quick lime (CaO 95.0%) in 507 parts of hot water at 80 ° C. was 4.
It was 0 ml. Silica powder (SiO ₂ 97.37%, Al ₂ O ₃ 0.9) with an average particle diameter of about 9 μm was added to the lime milk.
9%) 53.21 parts were added to bring the total amount of water to 22% of the solid content.
A raw material slurry was obtained by mixing so that the weight of the raw material slurry was 12 kg / cm ² , the temperature was 191 ° C., and the volume was 3
Rotation speed of 1 in an autoclave with 000 cc and an inner diameter of 15 cm
74r. p. The hydrothermal synthesis reaction was performed for 3 hours while rotating the stirring blade at m to obtain a crystal slurry. When this crystal slurry was dried at 100 ° C. for 24 hours and subjected to X-ray diffraction analysis, it was confirmed to be tobermorite crystals. When this crystal slurry was dried on a slide glass and observed with an optical microscope, spherical secondary particles having an average outer diameter of 48 μm were recognized.
Further, a surfactant was added to the slurry and mixed, allowed to stand for 48 hours to spontaneously settle, and then dried at 100 ° C. for 48 hours to cut out a part of the naturally settled molded body, which was fixed with Canadian balsam. Then, after polishing this, the above Canadian balsam was removed with xylene to obtain a polishing sample. Observation of this sample with a scanning electron microscope revealed that the tobermorite crystals were densely aggregated to form spherical secondary particles. When these secondary particles are dispersed and observed with an electron microscope, the length is 0.1 to 10 μm and the width is 0.1 to 2 μm.
m plate-like crystals, length 0.1-10 μm, width 0.05-
Needle-like crystals of 0.5 μm were observed. The properties of the secondary particles are as shown in Table 19.

[Table 19] Also, the crystal slurry obtained above is press-molded, and the temperature is 120 ° C.
The degree of preferential orientation of the molded body obtained by drying for 20 hours was as shown in Table 20.

[Table 20] Next, 7 parts of glass fiber, 5 parts of pulp and 3 parts of Portland cement as an additive are added to 85 parts (solid content) of the crystal slurry obtained above, and press-molded in the same manner to 120 ° C.
And dried for 20 hours to obtain a molded body. The physical properties of the obtained molded product are as shown in Table 21.

[Table 21]

[Brief description of drawings]

1 shows a 100 × optical micrograph of spherical secondary particles of tobermorite crystals of Example 1. FIG.

FIG. 2 shows an electron micrograph at 7500 times in which spherical tobermorite crystal secondary particles of Example 1 were dispersed.

FIG. 3 shows a scanning electron micrograph (600 times) of a polished surface of a spontaneous sedimentation molded article of Example 1.

FIG. 4 shows a scanning electron micrograph (600 times) of a polished surface of a spontaneous precipitation molded body of Example 2.

FIG. 5 shows a scanning electron micrograph (600 times) of a polished surface of a tobermorite molded article of the present invention (density 0.201 g / cm ³ ) of Example 2.

Claims (4)

[Claims] Claims: 1. A molded article formed by interconnecting tobermorite crystals or secondary spherical particles having a small amount of other calcium silicate crystals entangled three-dimensionally with each other. , The spherical secondary particles have an outer diameter of 10 before molding.
˜120 μm, the hollow rate thereof is 30% or less, and the density of the natural sedimentation molded body thereof is 0.12 g / cm ³ or less, a calcium silicate molded body. 2. The molded product according to claim 1, further comprising at least one kind of an inorganic fiber and a binder in the molded product. 3. The bulk density of the molded product is 0.3 g / cm ³ or less, and the spherical secondary particles constituting the molded product are spherical secondary particles in a scanning electron micrograph (600 times) of the polished surface of the molded product. The molded product according to claim 1, which is compressed and deformed to the extent that the presence of secondary particles can be confirmed. 4. The molded article has a bulk density of 0.3 g / cm ³ or more, and the spherical secondary particles constituting the molded article are flattened and compressed and deformed to such an extent as to exhibit a remarkable preferential orientation. The molded article according to claim 1, which is characterized in that.