CA1094583A

CA1094583A - Hardened product composition and process of producing the same

Info

Publication number: CA1094583A
Application number: CA239,958A
Authority: CA
Inventors: Tomisaburo Azuma; Kazuto Ichimaru; Takeru Murakami; Kouichi Tateno
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1974-11-15
Filing date: 1975-11-17
Publication date: 1981-01-27
Also published as: FR2291163A1; DE2551311B2; AU8667875A; GB1535052A; FR2291163B1; DE2551311C3; DE2551311A1

Abstract

ABSTRACT OF THE DISCLOSURE
A hardened product composition composed of calcium aluminate sulfate hydrate and at least one of a fibrous material, a high molecular weight material, a fatty acid, and calcium silicate as a reinforcing agent and a process of producing the hardened product composition. The hardened product prepared from the composition is quite excellent as building materials.

Description

lO't'lS83 BACKGR()UND OF T~E I~iVE~T l ON
1. Field of the Invention .... _ The present invention relates to a hardened product composition containing calcium aluminate sulfate hydrate and, more particularly, the invention relates to a hardened product composition containing calcium aluminate monosulfate hydrate (3cao~AQ2o3~caso4.l2H2o) (hereinafter, the compound is referred to as MSH), calcium aluminate trisulfate hydrate (3CaO.AR203.
3CaS03.31-32H20) (the compound is referred to as TSH), or as a mixture of them. The invention further relates to a process of producing such a hardened product composition.

2. Description of the Prior Art As inorganic hardened product compositions, there have hitherto been known gypsum, calcium silicate, and cements but they have such faults that the water resistance is inferior as in gypsum, a free alkali is contained as in cement, and the production step is complicated to increase the production cost as in calcium silicate and thus they are unsatisfactory for practical use.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a novel hardened product composition having excellent properties and a process of producing such a hardened product composition.
Other object of this invention is to provide a hardened product composition possessing excellent water re-sistance and containing no free alkali and also a process of producing the novel hardened product composition.

3~ Still other object of this invention is to provide a hardened product composition possessing excellent mechanical 10'3 ~583 1 strength and a process of Droducing the nov~l hardened product composition.
Further object of this invention is to provide a hardened product composition prepared by a simple production step and also a process of producing the hardened product composition.
These objects of this invention can be attained by this invention. That is, according to the present invention, there is provided a hardened product composition comprising MSH, TSH, or a mixture thereof and having blended therewith at least one of fibrous materials, high molecular weight materials, fatty acids, and calcium silicate as a reinforcing agent.
- The invention also provides a process of producing the above-mentioned hardened product composition.

BRIEF DESCRIPTION OF THE DRAWINGS

- Figures 1 to 23 show the X-ray diffraction charts of the hardened product compositions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
In an embodiment of this invention, a fibrous material is used as a reinforcing agent and a fibrous material which can reinforce the hardened product can be used in this invention for the purpose. Examples of the fibrous materials used in this invention are inorganic fibers such as glass fibers, asbestos, carbon fibers, rock wool, etc.; synthetic fibers such as nylon fibers, polypropylene fibers, acrylic fibers, polyester fibers, polyvinyl formal (vinylon, a trade name) fibers, polyvinyl alcohol fibers, etc.; and natural fibers such as pulp, flax, wood flou., wool, cotton linter, etc. They may be used individually or as a mixture of them.

10~45f33 1 ~he compounding ratio of the fibrous material may be suitably selected according to the purpose of using the hardenGd product but is generally less than 35 parts by weight (the "parts" in this specification are all by weight) per 100 parts of the hardened product composition (the composition may further contain other materials than the fibrous material). Furthermore, the proportion of the fibrous material differs according to the kind of the fibrous material employed. For example, it is preferred to employ 3 to 30 parts by weight of asbestos, 3 to 20 parts of pulp or wood flour, or 3 to 10 parts of synthetic fibers such as nylon fibers. In addition, if the fibrous material is combustible, it is preferable that the amount of the fibers be less than 20 parts.
In the present invention high molecular weight materials, such as organic polymers or organic high molecular weight materials may be used as the reinforcing agent. The high molecular weight material used contributes to increase the strength, in particular, the bending strength of the hardened product as well as to prevent the occurrence of peeling and to prevent the occurrence of carbonation for preventing the deterioration of the hardened product. Accordingly, a high molecular weight material has a binder effect, that is, a surface covering function for the hardened product. Practical examples of the high molecular weight materials used in this invention are natural high molecular weight material, such as starch, gelatin, casein, etc.; water-soluble resinsr such as polyvinyl alcohol, urea resin, melamine resin, water-soluble phenol resin, polymethylolacrylamide, polyacrylic acid, etc.;
and water-insoluble resins which may be preferably used as emulsions, such as polyvinyl acetate, polyacrylate, epoxy resin, 1 ethylene-vinyl acetate copolymer resin, ~henol resin, etc. They may be used individually or as a mixture of them. In addition, the aforesaid polym~rs having pH of higher than 7 are preferably used since they do not hinder the reaction of forming TSH
from ~ISH.
There is no particular limitation about the addition amount of the high molecular weight material but is is preferred that the addition amount of it be 0.S to 10~ by weight of the total amount of the solid components. If the proportion of the polymer is over 10% by weight, the hardened product is deterio-rated, for example, becomes com~ust;ble by the increase of the organic material, the effect of increasing the properties of the hardened product is not further increased, and, as the case may be, the addition material tends to hinder the formation of MSH and TSH.
Moreover, in the present invention calcium silicate can also be used as the reinforcing agent. The use of calcium silicate can provide a hardened product having a light weight and a high strength. In this case, it is preferred to use calcium silicate having a bu~k as large as possible. For example, there is a bulky so-called activated slurry prepared by mixing a CaO component such as CaO, Ca(OH)2, and a mixture of them and a SiO2 component such as diatomaceous earth, silica, zeolite, etc., at a CaO/SiO2 ratio of 0.7 to 1.8 by mole ratio and reacting the mixture in the presence of water as a slurry state for 1 to 72 hours at 80 to 240C while preventing the escape of water from the system, that is, under a wet heat condition. This material is recognized as gel-like CSH(I), CSH(II), tobermorite, xonotlite, etc.
It is preferred from a point of obtaining the effect 10~583 1 of using the additive that the mi~frg ratio o- calcium silicate to TSH and/or MSH be from 0.5/9.5 to 9/1 by weight.
The composition produced by hardening the mixture having the aforesaid mixing ratio is in such a state that the fine crystals of TSH and/or MSH are present in the spaces among the crystals of calcium silicate to provide a quite strong hardened product. Furthermore, the hardened product thus obtained has a low specific gravity, a high water resistance, and a high strength and the product is thus suitable as building materials, etc.

The hardened product composition of this invention as described above contains TSH and MSH as necessary components but when the material is brought into contact with carbon dioxide gas, the product is, as the case may be, decomposed, which is called "carbonation". For preventing the occurrence of the carbonation, it is an effective means to use the aforesaid high molecular weight material. However, a particular means can be applied to the product for preventing the carbon-ation~ That is, a fatty acid is added to the hardened product.
Thus, the occurrence of the carbonation can be effectively prevented by perhaps the action of the carbonyl group of the fatty acid.
The fatty acid may be incorporated in the product by the same way as the case of adding the high molecular weight material as will be described below.
As the fatty acids used in this invention,there are various kinds of fatty acids and fatty acid derivatives but, in particular, the fatty acids having a fatty acid radical of 10 to 23 carbon atoms are preferably used.
The fatty acid having less than 10 carbon atoms acts lO~S~33 1 as an acid owing to the solubilitv in i~a.er and thus tends to decompose TSH and .~SH Ho~ever, e~-en if the carbon number is less than 10, the fatty acid may be used if the acid does not decompose TSH and MSH.
Examples of the fatty acid derivatives used in this invention are esters, preferably alkyl esters having 5 to 23 carbon atoms, metal salts, ammonium salts, and fats and oils.
As the metals for the metal salts, there are aluminum, zinc, calcium, magnesium, lead, cadmium, barium, sodium, potassium, cobalt, manganese, copper, zirconium, nickel, chromium, and iron. Practical examples of the fatty acids and fatty acid derivatives used in this invention are stearic acid, behenic acid, capric acid, palmitic acid, myristic acid, the metal salts of the acids, such as zinc salts, calcium salts, cadmium salts, magnesium salts, aluminum salts, etc., the alkyl esters of the acids, and fats and oils such as coconut oil, soybean oil, linseed oil, etc. The fatty acids mentioned above may be used as powders or as dispersions of them.
There is no particular Limitation about the pro-portion of the fatty acids for obtaining the effect of them butthe proportion thereof is preferably about 0.2 to 5~ by weight of the amount of TSH and MSH. If the proportion of the fatty acid is less than 0.2% by weight, the effect thereof is in-sufficient while if the proportion is over 5% by weight, it tends to hinder the hardening of MSH and TSH.
Thus, when the hardened product containing the afore-said additive is brought into contact with carbon dioxide gas, or practically speaking, the hardened product is exposed to air, the occurrence of the carbonation can be prevented as well as the reduction in strength of the hardened product when the product is carbonated can be prevented.

lO9~S83 1 However, if the reduction in strength gives no severe problem to the purpose of uslng the hardened product, the hardened product may, as the case may be, carbonated since the specific gravity or the product is reduced by the carbonation.
In such case, after hardening TSH, the hardened product may be forcibly carbonated.
It is desirable to carry out the carbonation at temperatures of from 20C to 100 C, preferably of 40 to 80C
and at a humidity of 60 to 100~ R.H. If the temperature is too low, the rate of the carbonation reaction is low and if the temperature is too high, the shaped product is sometimes accompanied by the formation of cracks. The reaction itself becomes faster as the temperature and humidity are higher (the reaction is faster when moisture exists in the reaction system).
In this case, it is preferable to pass carbon dioxide gas at a constant speed so that the shaped product lS always brought into contact with fresh carbon dioxide gas. In addition, the same object can also be attained by allowing to stand the shaped product in the air without need of a specific carbonation step.

TSH becomes a crystalline mixture of CaC03, AQ203.nH20, and CaS04.2H20 by carbonation, and the extent of the carbonation can be selected desirably according to the purpose of using the hardened product.
In this invention, the aforesaid additives may be used as a combination of two or more additives. By using the additives together, the addition effects of them may be obtained.
These additives may further ~e used together with other additives such as fillers, pigments, lubricating agents, etc.
The fillers are used for obtaining a caking effect and, 1 in particular, for preventing th~ stripping of layer of th~
plate hardened product and examples of the fillers used in this invention are bentonite, kaolin, sericite, etc. The amount of the filler used differs desirably according to the pùrpose of using the hardened product but in general is less than 35%
by weight of the total amount of the hardened product.
Also, the lubricating agent is used as a mold r~-leasing agent and examples of the lubricating agent are wax, a metal stearate, such as salt of Ca, Zn, Cd and Pb, etc. A
proper amount of the agent is less than 5% by weight of the total amount of the hardened product.
The pigment may be selected desirably and the amount of it may also suitably be selected.
The addition of the additives to the hardened product composition of this invention may be practiced in any steps of -producing MSH or TSH or further may be added to the product after the production of MSH or TSH.
In the case of using the high molecular weight material, the high molecular weight material contributes to act as a binder for TSH and/or MSH or act to coat the surface of the hardened product.
For mixing TSH and/or MSH with the high molecular weight material, in the production step of MSH and TSH the high molecular weight material may be first mixed with the CaO
component, the AQ203 component, and the CaS04 component followed by the production of TSH and MSH to provide the hardened product.
Moreover, the high molecular weight material is added to MSH
or the raw materials for TSH, such as 3CaO.3AP.203.CaS04 and then the TSH may be produced to provide the hardened product con-3~ taining the high molecular weight material. In the case of 10~45R3 1 employlng the mixing means o~^ the hish molecular weight ma'e~ial re~uiring the reaction or forming MSH and/or TSH, a care mus~
be taken not to hinder the formation of MSH and TSH in the mixture. Furthermore, the high molecular weight material may be mixed with TSH or a mixture of TSH and MSH forme~ beforehand.
There is no limitation about the mixing means and, for example, a kneader, a blender, etc., may be properly employed.
In addition, the following specific mixing method may be employed. ~hat is, the hardened product of MSH, TSH, etc., is first prepared, the surface of it is then coated with the high molecular weight material or a solution or an emulsion of it, and then the coated product is, if necessary, dried.
Still further, the hardened product is impregnated with a monomer and the monomer may be polymerized in the hardened product. This method is effective when the hardened product composition of this invention is porous and thus is easily impregnated with the monomer.
The hardened product composition of this invention includes the case containing MSH or TSH individually as the main component and also the case containing both of MSH and TSH as the main components. In the latter case, the hardened product composition containing TSH and MSH may be prepared by controlling the operation condition for producing TSH or MSH or further the similar hardened product composition may be prepared using MSH
and TSH which were prepared beforehand separately.
MSH, TSH and the dehydration products of TSH prepared by any manner can be used in this invention. For example, they may be prepared as follows:
MSH can be prepared by reacting the lime component~
the alumina component, and the calcium sulfate component in the _ g _ 10~-~583 1 presence of water at tempera'_ures o 100 to 200C.
In this case, as the CaO component used in the reas.ion, there are calcium oxide (CaO), calcium hydroxide ~Ca(OH)2), and a mixture of them; as the alumina component, there are alumina (AQ2o3)~ hydrated alumina (AQ2o3.nH2o~ wherein n is a positive number), activated alumina, aluminum hydroxide (AQ~OH)3)~ and the mixtures of them; and as the calcium sulfate component, there are anhydrous gypsum (CaSO4) r hemihydrate gypsum (CaSO4.1/2H2O), gypsum dihydrate ~CaSO4.2H2O), and the mixture Of them. In addition, as the alumina components described above, activated alumina, hydrated alumina, and aluminum hydroxide are particularly preferred from the point of reactivity, that is, the yield for product.
There is no particular limitation about the mixing ratio of these raw materials but it is preferred that the raw materials are used at a mixing ratio near the mole ratio of the composition of MSH. In general, the mixing ratio of these components is 2.4 to 3.3 moles, preferably about 3 moles of the lime component, 0.8 to 1.0 mole, preferably about 1 mole of the alumina component as AQ2O3, 0.8 to 1.0 mole, preferably about 1 mole of the calcium sulfate component, and more than 12 moles of water. The material is reacted at 100 to 200C, preferably 160 to 180C under a so-called wet heat condition or under the condition of preventing the escape of necessary water from the system. If the reaction temperature is higher than 180C, the by-production of C3AH6 tends to increase, while the reaction temperature is lower than 160 C, the reaction period of time prolongs to some extent. Also, the reaction period of time required for finishing the reaction depends upon IO the mixing ratio of the raw materials, the reaction temperature 109.~3 l and the stirring condition of the reaction system but is ordinarily l to 8 hours. ~or example, when the reaction tem-perature is about 100C, the reaction period of time required is about ~ hours and if the reaction temperature is 200C, a satisfactory result is obtained in about one hour. Also, since the reaction requires a presence of water and the reaction is carried out at temperatures higher than 100C, the reaction requires also an autoclave or a high-pressure reaction vessel for carrying out the reaction. The reaction is carried out at the pressure of preventing the escape of water from the reaction system, that is, the pressure higher than the saturation vapor pressure at the reaction temperature.
Furthermore, the state of the reaction system at the reaction differs according to the amount of water used. That is, if the amount of water used is less, for example, the amount of water is about 0.5 to l.0 part by weight per one part by weight of the solid components, the mixture of the raw materials is carried out in a shaped state or pseudo-solid state, while if the amount of water is large, that is, the amount of water is about 1.1 to 5.0 parts by weight per one part by weight of the solid components, the reaction mixture is reacted in a slurry state. For preparing MSH, the reaction may be carried out in a slurry state with stirring but in the case of producing MSH as a hardened product or a shaped product, it is preferred to carry out the reaction in the shaped state or - the pseudo-solid state. For reaction the mixture in a shaped state or pseudo-solid state, it is preferred that the mixing ratio of the reaction system be 3.1 to 3.3 moles of the lime component, about l.0 mole (as AQ2O3) of the alumina component, and 0.9 to l.0 mole of the calcium sulfate component. It is also lO~ ~S~3 1 preferred to use each of the r~ materials as a ~owder state and if the size of the powders of the raw materials is 100 mesh (by the sieve of Taylor) under, satisfactory results can be usually obtained. Furthermore,more preferred results are obtained by mixing the raw material components and grinding the mixture by means of a vibration mill, etc. In addition, the raw materials may be mixed in any order.
To the MSH prepared by the aforesaid process or other process is added the CaS04 component and the mixture is reacted in the presence of water at temperatures lower than 120 C to provide TSH.
In the aforesaid reaction, there is no particular limitation about the amount of the calcium sulfate component used, but the amount thereof is preferably about the theoretical amount, that is, 0.7 to 1.2 moles, more preferably 0.98 to 1.0 mole, per mole of MSH for the purity and the yield of the pro-duct. The amount of water required in the reaction may be more than 19 moles per mole of MSH, that is, may be the amount capable of maintaining the water of crystallization required by TSH.
If the amount of water necessary for the step of producing TSH
is secured in the production step for MSH, the addition of water is unnecessary but if the amount of water required in the step of producing TSH is not secured, the insufficient amount of water must be supplemented. However, if the amount of water necessary for the shaping operation of the mixtures in the pro-- duction step of TSH is present, this condition can be almost satisfied.
If the reaction temperature is over 120C r the decomposition of TSH occurs, which is undesirable in the process of this invention. Furthermore, in the temperature range of 109^~LS83 1 100 to 120C, the form~tion ra e of TS~ is co~paratively 1GW
and thus the reaction period of time required for finishing _he Lormation of TS~ is prolonged or in t~is case a mixture of MS~, TSH, and gypsum is obtained. The most preferred temperature range is 50 to 95C and in this temperature range, the formation rate of TSH is highest. If the reaction temperature is lower than 10C, the formation of TSH is delayed.
In the aforesaid reaction, the reaction period of time differs according to the temperature condition as well as the purity of the product desired but is usually from one hour to one month and also is about 10 minutes to 10 hours under an ordinary preferable condition.
The hardened product comprising the mixture of MSH
and TSH is superior in streng-th to the hardened product com-prising each of MSH and TSH, individually. In order to obtain the mixture of MSH and TSH during the production of the hardened product, the reaction period of time and the reaction temperature may be controlled as mentioned above or further a mixture containing a reduced amount of the CaSO4 component may be subjected to the reaction.
The hardened product comprising a mixture of 1 mole of TSH and 0.01 to 4 moles, preferably 0.02 to 0.7 mole of MSH, is excellent in strength.
In the reaction system containing a larger proportion of MSH, the strength of the hardened product tends to become lower, on the other hand, in the reaction system containing a less proportion of MSH, the expandability of the reaction system at the production of the hardened product tends to become higher. In the reaction system containing MSH and TSH at a suitable mixing ratio, the hardened composition composed of the 10~5~33 1 plate crystals of the former ar.d the ac~cular crystals of the latter intermingled ea~h other and thus having a high strength can be obtained.
TSH can also be prepared by reacting 3CaO.3AQ2O3.CaSO4, 3CaO.AQ2O3.6H2O, or a mixture of the CaO component and the AQ2O3 component together with the CaSO4 component in the presence of water at temperatures of lower than 120C, preferably of 50 to 95C. It is preferred, in this case, to use the raw materials at a mixing ratio near the theoretical mole ratio of the product.
TSH can be further prepared by reacting the mixture of the lime component, the AQ2~SO4)3 component, and water.
Also, the dehydration product of TSH is useful for the production of the hardened product of th s invention and the dehydration product of TSH can be prepared by heating TSH
to release a part or the whole of the water of crystallization thereof. In this case, it is undesirable to carry out the reaction under a severe condition of causing the decomposition of TSH over the release of water of crystallization although this is not intended to limit the heating temperature. The temperature is usually lower than g00C, preferably of about 50 to 200C. The reaction period of time corresponding to the temperature is fxom about 10 hours to about 30 minutes. The product obtained by the treatment is shown by the formula 3CaO.AQ203.3CaS04.nH20, wherein n is a number of 0 to 31, pre-ferably 10 to 20f In addition, the amount of water of crys-tallization is a statistical value (i.e., the mean value of the number of crystallization water contained in the dehydration products of TSH). If n is less than 10, the dehydration tends to be reluctant to occur. If n is not larger than 20, the form of -- 1 . --109~583 1 the crystal of ~SH collapses and it is recrystallized when water is added to it. Thus, in this case, the crystals are in~ermingled to provide a hardened product having quite high strength. The tendency of recrystallization becomes lower as the number of n becomes larger over 21.
The hardened product of MSH is prepared in the same manner as the preparation of MSH, that is, a lime component, an alumina component, a calcium sulfate component, and water are mixed at a predetermined ratio and after adding, if necessary, additives such as fibrous reinforcing agents to the mixture, the resultant mixture is, with or without being shaped, cured at 100 to 200C. When the composition is not shaped prior to curing, the composition is hardened in a bulk state and the hardened product is used as it is or is shaped into a desired shape.
The curing condition is almost same as the condition of producing MSH but when the shaped product is cured in a solid state, the heat conductivity is lower, which requires a longer period of time for finishing the procedure. The curing operation is carried out under the condition that necessary water of crystallization does not escape from the reaction system. Such a condition is usually called as "wet heat condition".
The aforesaid additives can be added to the reaction system at any step before the mixture is hardened. That lS, by adding the additives to the raw materials of MSH, the hardened product containing the additives can be obtained simul-taneously with the formation of MSH.
Then, the productions of the hardened products of TSH
~ and the dehydration product will be explained.

~()9~5~3 The hardened produc~ containing TSH is produced Usi?.5 MSH, the gypsum compon~nt and water and the curing condition, i.e., reaction temperature is same as the condition of producins TS~. That is, klSH, a lime component, and water are mixed at a predetermined ratio and after adding, if necessary, additives such as fibrous reinforcing agents, etc., to the mixture, the resultant mixture is, with or without being shaped, cured in the presence of water necessary for the formation of water of crystallization of TSH.
The hardened product of TSH can also be produced simultaneously with the formation of TSH by selecting the amount of water properly at the case of producing TSH by reacting 3CaO.3A~2O3.CaSO4, 3CaO.AQ2O3.6H2O, or a mixture of the CaO component and the A~2O3 component with the CaSO4 component in the presence of water. In this case, when additives are added to the reaction product and after shaping the mixture, the shaped mixture is reacted, a shaped hardened product is obtained. This will be further explained more in detail by the following example.
That is, a mixture of the lime component, the alumina component, and the gypsum component at a mixing ratio correspond-ing to the composition of TSH is, after adding thereto, as the case may be, the additives such as fibrous reinforcing agents, etc., cured under almost the same condition (or the wet heat condition) as the aforesaid condition of producing TSH.
The preferred range of the mixture of the raw materials employed for producing TSH is 2.4 to 3.5 moles, preferably about 3 moles of the lime component, 2.4 to 3.5 moles, preferaby about 3 moles of the gypsum component, 0.8 to 1 mole, preferably about 1 mole of the alumina component, and more than 32 moles of water including water of crystallization.

~0945~3 1 Another embodiment o~ roduclng the TSH hardened product of this inventio~, a definite amount of water is added to a fine powder of TSH prepared beforehand and, after adding, if necessary, the additives such as fibrous reinforcing agents, etc., to the mixture, the resultant mixture is cured under the aforesaid condition and dried to give the hardened product of this invention. In this case, TSH is partially dissolved and it is recrystallized in the drying step to provide the hardened product. The amount of water employed may be properly changed according to the shaping method employed.
In the case of producing the hardened product of the dehydration product of TSH, a mixture of the dehydration product of TSH and a proper amount of water is shaped into a desired shape and then cured at 20 to 120C for l to 10 hours and dried by the following manner to provide the aimed hardened product.
The proper amount of water means the amount of water sufficient for securing water of crystallization ~31-32H20) of TSH and further means the sufficient amount of water for providing the properties convenient for mixing with other additives or for shaping the mixture. Practically speaking, the amount of water differs according to the amount of residual water of crystallization retained in the dehydration product of TSH but on considering the shaping property, the amount of water employed is more than 30 parts by weight per lO0 parts by weight of the dehydrate of TSH.
In addition, other additives such as a fibrous reinforcing agent, a filler, a high molecular weight material, a pigment, etc., may be added to the reaction mixture.
MSH, TSH, a mixture of them or the dehydration pro-duct of TSH may be shaped by any means. However, since the 10945~33 1 state of the hardened comp~sltlo.~ dif_ers acoording to theamount of water used, a shaping me~hod suitable for the state shall be selected. That is, if the amount of water is less, an extrusion molding method or a compression molding method is suitable while if the amount of water is iarge and the com-position is in a slurry state, a pressing method or a casting method is suitable. Also, if the amount of water in a slurry is more larger, a paper manufacturing method ~wet machine method) is suitably employed. In addition, in the case of employing a casting method, it is preferred that the composition contains 40 to 100 parts by weight of water per 100 parts by weight of the solid components in the composition, while in the case of employing a paper manufacturing method, it is preferred that the composition contains 5 to 20 parts by weight of water per 1 part by weight of the solid components.
-If necessary, the hardened product may be dried before use. The drying operation is generally carried out at 60 to 100 C Ithe surface temperature of the hardened product), preferably at temperatures lower than 60 C. If the content of ~ water in the hardened product is high, the product may be dried at 60 to 100C but after the water sontent is reduced, water of crystallization is liable to be evaporated off and hence in such case it is desirable to dry the component at tem-peratures lower than 60C.
The hardened materials thus obtained are quite excellent in strength and water resistance.
In the case of producing TSH, in particular, the hardened product of it from MSH, a reaction controlling agent may be used.
Among the reaction controlling agents, examples of 5~3 1 the retarding a~ents used in this invention ~or retarding the production rate of TSH ar~ sodium yluconate, gluconic acid, sodium citrate, citric acid, sodium hexametaphosphate, starch, carboxymethyl cellulose, gelatin, calcium oxide, and calcium hydroxide. They may be used individually or as a mixture of them. They are materials having COOH group and OH group together or are high molecular protective colloids. They are properly added to the reaction system and there is no particular limitation about the addition amount of them but the amount is preferably 0.03 to 0.5~ by weight of the total amount of MSH
and the CaS04 components. If the amount is less than 0.03% by weight, the effect of the addition of it is not obtained while even if the amount is over 0.5% by weight, no further effect does increase. In the case of using calcium oxide for the purpose, the amount is 0.5 to 5% by weight, preferably 1 to 3%
by weight.
In the case of producing the hardened product of TSH
from a mixture of, for example, MSHr a gypsum component, and water, the pot life of the mixture is usually short and the mixture begins to harden after about 5 to 10 minutes. This is inconvenient for carrying out the shaping operation, molding operation, etc., of the mixture. Thus, by adding the aforesaid reaction retarding agent to the mixture, the pot life of the mixture can be prolonged conveniently. In particular, when a shearing stress is appliea to the mixture by kneading, molding, etc., a mechanical reaction is liable to occur and in such case the addition of the reaction retarding agent is quite effective for preventing the occurrence of the mechanochemical reaction.
Also, as the reaction accelerators for hastening the 3~ formation rate of TSH, the aromatic carboxylic acids having the ~0'~;~583 1 following general formula and anhydrides thereof can be used.
[R~-~COOH~
wherein n represents an integer from 1 to 4; R represents ~ , ~ or They are, for example:
Rl-COOH such as ~COOH

~COOH ,~COOH
~COOH such as ~COOH and HOOC~3~OOH

R3~ \0 such as ~C\

O Ol Ol O
0~ ~R~ ~0 such as 0~c~

HOOC~ / COOH HOOC ~ OOH
R5 such as ~ and HOOC COOH HOO OOH

HOOC ~ ~ COOH
HOOC ~ COOH

5~3 o HOOC-R6 o such as~ 11 \o \~ C/

/ COOH HOOC JCOOH
HOOC-R such as COOH
`' ~OOH

wherein Rl - R7 represents ~ ~ or In particular, the aromatic carboxylic acids which are insoluble or sparingly soluble in water ~the solubility of less than 0.5 g/100 g-water at 20C), such as isophthalic acid, terephthalic acid, o-phthalic acid, benzoic acid, phthalic anhydride, and the like are preferred although the reaction accelerators used in this invention are not limited to them.
They may be added individually or as a mix-ture of them.
~O At use, the aromatic carboxylic acid or the anhydride may be added to the reaction system of MSH, the gypsum component, and water.
In this case, it is preferred that the amount of the aromatic carboxylic acid or the anhydride be 0.2 to 5.0% by weight to the total weight of MSH and the gypsum component although the value is not intended to limit the invention in any way. Even if the amount of the aromatic carboxylic acid is over 5.0% by weight, the reaction acceleration effect does not further increase in general and if the amount is too much, the effect sometimes decreases. On the other hand, if the amount ~0~45~3 1 is less than 0.2% by weignt r a remarkable reaction accelerat~on effect will be not obtained.
The acceleration of the reaction is necessary in the case of forming some moldings, etc., of the product and also is convenient in the case of producing TSH directly since the reaction period of time can be shortened.
As described above, the hardened product composition of this invention containing MSH and/or TSH as the necessary component and the process of producing them are quite novel and useful.
MSH or TSH itself is useful as an inflating agent for cement and the hardened materials of MSH and/or TSH are useful as new building materials such as ceiling materials, wall materials, flame retarding agents, etc., as well as electric materials such as insulating plates. The hardened materials are comparatively light and have such properties that the strength is high, the solubility of TSH and MSH in water is low, and the water resistance is high. For example, the solubility of TSH in water is 0.027 g/100 g-H2O at 20C and thus they are superior to gypsum.
Also, by preventing the occurrence of carbonation, the hardened products possessing higher water resistance can be obtained.
Furthermore,using additives such as a fibrous rein-forcing agent, a high molecular weight material, etc., the hardened materials possessing higher strength are provided.
In this case, TSH and MSH do not show strong alkalinity, such reinforcing agents as glass fibers can be used without accompanied by the reduction of the reinforcing effect with the passage of time and thus the hardened products of this invention are excellent in this point.

~0~583 1 Furthermore, TSH and ~ have a large amount of ~ater of crystallization and thus in the case of fire, the hardened products show the property of absorbing combustion energy and hence they are useful as fire-retarding building materials.
Then, the invention will practically be described by referring to the following examples, in which parts and percentages are all by weight. Also, the bending strength is the destruction load per unit cross section when a sample of 25 mm width having an optional thickness is formed into spun 50 mm.

The temperature of water used in measuring the wet bending strength, the water absorption and the weight loss is 25C unless the temperature are not shown specifically.
The particle sizes of materials which are shown in mesh are measured by the sieve of Taylor ~lO0 mesh = 149 lu of diameter, 325 mesh = 44 /u of diameter).

A mixture of 150 g of calcium oxide, 90 g of activated alumina, and 130 g of hemihydrate gypsum was ground and mixed for 30 minutes by means of a vibration mill, 500 g of water and 40 g of asbestos were added to the mixture and the resultant mixture was also mixed in a high-speed mixer so that the asbestos was opened. The slurry composition thus obtained was poured in a mold of lO0 mm x 200 mm x lO mm and allowed to stand for 20 minutes to coagulate the composition. The coagula-tion product was maintained to 160C for 3 hours in an autoclave at a pressure of 8 kg/cm gauge to cure under wet heat con-dition and to provide a hardened product. The product was dried and the properties of it were measured. The results were as follows: That is, the bulk specific gravitv was 0.9, the bending ~094~i33 1 strength was 48 kg/cm2t and the weight loss when immersed i~
running water for 24 hours at 25C was 0.73~.

EX~IPLE ?

A mixture of 185 g of calcium oxide, 156 g of aluminum hydroxide, 172 g of gypsum dihydrate, 75 g of asbestos, and 5,000 g of water was mixed with stirring by means of a jet mixer until the asbestos was opened to provide a slurry. The slurry was treated by means of a paper machine having a filter area of 300 mm x 300 mm to provide a mat of 2 mm thick. Five sheets of the mats thus formed were piled and were subjected to a compression molding at a pressure of 0, 10 kg/cm2, 30 kg/cm2, 50 ks/cm2, or 80 kg/cm2 to form a plate. Each plate was cured for 2 hours at 180C in an autoclave under a wet heat con-dition to provide a hardened plate. The properties of the product are shown in Table 1.

TABLE l Molding Pressure (kg/cm2) 0 10 30 50 80 Bulk specific gravity 0.82 1.03 1.23 1.41 1.70 20 Bending strength (kg/cm2) 42 50 76 105 193 Weight loss when immersed in running water for 24 0.87 0.60 0.38 0.24 0.21 hours at 25C

To 5 liters of water was added 60 g of Canadian chrysotile asbestos 6D and they were mixed for 2 minutes by means of a jet mixer at hîgh speed to open the asbestos. To the asbestos were added 155 g (2.8 moles) of calcium oxide, 156 g (2 moles) of aluminum hydroxide, and 516 g (3 moles) of gypsum dihydrate and they were mixed for 6 minutes at high speed. To the mixture were added 20 g of glass fibers of chopped - 2~ -lO9~S83 1 strands ~made by Nitto Boseki ~.K.~ of 1.27 cm length and 9 y diameter and they were mi~ed for 20 seconds. The mixture was treated by means o~ a batch type paper machine having a fllter area of 300 mm x 300 mm to provide a wet mat. The wet mat was pressed by a straight hydraulic pressing machine at a pressure of 20 kg/cm to squeeze off water and after allowing to stand for 10 days at 20C,the pressed mat was maintained for 2 hours at about 50C to provide a hard and strong inorganic hardened product of TSH. The properties of the product are shown in Table 2. That is, the product had high water resistance and high strength. In addition, the pH of the slurry was 8.4.

Bulk specific gravity 1.02 Bending strength 105 kg/cm2 Wet bending strength (water 2 content 42~ by weight~ 73 kg/cm Weight loss when immersed in running water for 24 hours at 25C 0.42% by welght First Step A mixture of 168 g of calcium oxide, 156 g of aluminum hydroxide, and 176 g of calcium sulfate (gypsum dihydrate) was ground and mixed for 30 minutes by means of a vibration mill and then 700 g of water was added to them to provide a slurry. The slurry was reacted for 4 hours at 180C
with stirring in an autoclave, whereby the slurry of MSH was obtained at a yield of 95~. The formation of MSH was confirmed by X-ray diffraction as shown in Figure 1, in which the peak M

shows MSH, the peak C shows Ca(OH)2, and the peak A shows A~O~)3.

- 25 ~

10~5~3 1 Second Step To the wh~le ~mount of the slurry of MSH obtained i~
the first step were added 198 g of calcium sulfate (gypsum dihydrate), 69.4 g of asbestos, and 2,000 g of water and they were mixed for 3 minutes at a high speed by means of a mixer to open the asbestos, whereby slurry was obtained. The slurry was formed in a mat of 8 mm thick by means of a paper machine having a filter area of 300 mm x 300 mm. The mat was cured for 5 hours at 20C and then dried for 5 hours at 50C to provide a hardened plate. The plate obtained was confirmed to be a mixture of MSH, TSH, and asbestos of 300 : 600 : 69.4 by weight ratio by X-ray diffraction analysis as shown in Figure 2, in which the peak T shows TSH and the peak S shows asbestos.
The plate prepared in the above process had a bulk specific gravity of 1.05 and a bending strength of 120 kg/cm2.
In addition, a hardened product prepared by the same way as above except that a mixture of only MSH and the asbestos of the same amount as above was used had a bulk specific gravity of 1.05 and a bending strength of 55 kg/cm and a hardened product prepared similarly by using a TSH-asbestos mixture had a bending strength of 63 kg/cm2. Thus, it has been confirmed that the use of MSH and TSH can provide a hardened product possessing a higher strength.

The slurry of MSH prepared by the first step in Example 4 was dried at 50C and ground into a powder smaller than 149 jU. Then, 400 g of the powder was mixed with 100 g of calcium sulfate (gypsum dihydrate) by means of a universal ~O~t45f~3 1 mixer and a dispersion pre?ared by dis?ersing 42 g of asbestos and 25.5 g of glass fibers as used in Example 3 in 500 g o water and opening the asbestos was added to the mixture to provide a slurry. The slurry was coagulated in a mold of 300 mm x 300 mm x 8 mm and the shaped material was cured for 3 hours at 50C under a wet heat condition, dried and hardened to provide a plate. As shown in the X-ray diffraction chart in Figure 3, the product plate was confirmed to be a mixture of MSH,TSH, asbestos, and glass fibers of about 15 : 760 : 42 :
25.5 by weight ratio. The plate had a specific gravity of 0.95 and a bending strength of 140 kg/cm2, while a hardened product prepared similarly using MSH, glass fibers, and asbestos at same mixing ratio had a bending strength of 73 kg/cm2 and a hardened product prepared similarly using a mixture of TSH, glass fibers, and asbestos had a bending strength of 90 kg/cm2.

After mixing uniformly ~00 g of the powder of MSH
prepared as in Example 4 and 100 g of calcium sulfate tgypsum dihydrate) by means of a universal mixer, a dispersion prepared by dispersing 42 g of asbestos and 68 g of pulp in 2,000 g of water and opening the asbestos and pulp was added to the above mixture to provide a slurry. The slurry was formed into a mat of 6 mm thick, cured for 2 hours at 90C under a wet heat condition, and then dried for S hours at 50 C to provide a hardened plate. The product plate was confirmed to be a mixture of MSH, TSH, asbestos and pulp of about 15 : 760 : ~2 : 68 by weight ratio. The product plate had a bending strength of 180 kg/cm2 and a specific gravity of 1.20 while a hardened pro-duct prepared by the same way as above using a mixture of MSH, 1 asbestos and pulp had a bending strength of 62 kg/cm2 and a hardened product prepared using a mixture of TSH, asbestos, and pulp had a bending strength of 65 kg/cm2.

E~MPLE 7 A mixture of 16.8 g of calcium oxide, 15.6 g of aluminum hydroxide, 17.2 g of gypsum dihydrate, and 100 g of water was reacted for 3 hours at 180C in an autoclave to provide MSH.

Then, 2 moles of gypsum dihydrate was added to the 1 mole of the MSH slurry obtained by the same way as above and after adding thereto water, they were reacted for 3 hours at 50C while preventing the escape of water to provide a TSH
slurry.
A slurry (solid content 937 g) prepared by mixing 0.8 mole of the MSH slurry and 2.2 moles of the TSH slurry prepared in the above procedures was mixed with 69.4 g of asbestos and after adding thereto 2,000 g of water, the resultant mixture was mixed for 3 minutes by means of a high 29 speed mixer to open the asbestos and then the mixture was formed into a mat. The mat was dried and the bending strength thereof was measured. The strength was 84 kg/cm2 and the specific gravity thereof 1.05.

A slurry having a solid content of 627 g prepared by mixing 1 mole of the TSH slurry and 0.01 mole of MSH slurry as prepared in Example 7 and after adding thereto 42 g of asbestos, 25.5 g of glass fibers as used in Example 3, and 500 g of water, the resultant mixture was mixed by means of a uni-versal mixer to open the asbestos, poured in a mold, and molded t by press to provide a plate of 8 ~m 'hick. Tne plate was d~ied for 5 hours at 50C to provide a hardened product. The spe_i~ic gravity and the bending strength of the product were 0.95 and 98 kg/cm , respectively.

A mixture of 70 g of aluminum sulfate ~AQ2(S04)3.18H20), 34 g of calcium oxide, and 300 g of water was reacted for 5 hours at 90C in a 500 mQ flask with stirring and then the reaction mixture obtained was filtered to provide the crystal of TSH.
Then, the whole amount of the TSH prepared above was mixed with 10 g of asbestos, 5 g of the glass fibers as used in Example 3, and 2,000 g of water to provide a slurry and a mat of 15 mm thick was prepared from the slurry. The mat was pressed at a pressure of 10 kg/cm to provide a plate of 10 mm thick and then by heating the plate for 5 hours at 50C, a hardened plate was obtained.

A mat prepared by the same manner as in Example 9 was pressed at a pressure of 60 kg/cm2 to provide a plate of 5.5 mm thick. By drying the plate for 12 hours at 50C, a hardened plate was obtained. The properties of the hardened plates prepared in Examples 9 and 10 are shown in Table 3.

Example 9 Example 10 Bulk specific gravity 0.41 1.02 Bending strength (kg/cm2) 38.5 118.0 Water solubility (%) 0.41 0.39 0 Note: The water solubility in the above table is the percentage of the weight loss of the product when i~mersed in running water for 24 hours at 25C.

109 ~SR3 1 EX~IPLE 11 A composition p~e?ared b~ mixing 200 g (about 3.6 moles) of calcium oxide, 175 g (about 2.2 moles) of aluminum hydroxide, and 700 g (about 38.9 moles) of water for 30 minutes by means of a universal mixer was cured for 60 minutes at 120C under a wet heat condition to provide an intermediate product. The intermediate product thus obtained was mixed with 435 g (about 3 moles) of hemihydrate gypsum and after further adding to the mixture 50 g of glass fibers and 30 g of asbestos, the resultant mixture was mixed for 2 minutes by means of a jet mixer, poured in a mold of 10 mm x 100 mm x 200 mm, and allowed to stand for 20 minutes to provide a coagulated shaped product. The shaped product was cured for 7 days in a chamber maintained at a temperature of 50C + 8C and a humidity of 100% to provide an inorganic hardened material. The properties of the inorganic hardened product are shown in Table 4.

Bulk specific gravity 1.12 Bending strength 150 kg/cm2 Weight loss when immersed in running water for 24 hours 0.51% by weight Expansion coefficient when immersed in running water for 24 hours + 0.5%

Water absorption when immersed in running water for 24 hours 28%

Wet strength when immersed in 2 running water for 24 hours at 25C 79 kg/cm Also, the result of the X-ray diffraction analysis of the hardened product is shown in Figure 4, which shows the presence of the peak (a) originated in TSH. In the figure, the peak (b) was the peak originated in the asbestos.

~0~4S83 I EX~IPLE 12 A composition ~ e?ared ~y mixing 23~ g ~about 3.1 moles) of calcium hydroxide, 175 g (about 2.2 moles) of aluminum hydroxide, and 5,000 g (about 278 moles) of water for 50 minutes by means of a universal mixer was cured for 40 minutes at abou~ 200C in an autoclave under a wet heat con-dition to provide an intermediate product. The intermediate product was mixed with 520 g (about 3 moles~ of gypsum dihydrate and the mixture was further mixed with 30 g ~about 3% by weight) of glass fibers of 0.9 cm length, 40 g of asbestos, and 20 g of polyvinyl acetal fibers of 1.75 cm length for 20 minutes by means of a universal mixer to provide a slurry. The slurry was formed into a mat of 8 mm thick by a paper machine having a filter area of 300 mm x 300 mm. The mat was placed for 60 hours in a chamber maintained at 90C + 3C and a humidity of 100% to cure under a wet heat condition and to provide a hard plate of an inorganic hardened product. The properties of the hardened product are shown in Table 5.

Bulk specific gravity 1.0 Bending strength 103 kg/cm2 Weight loss when immersed in running water for 24 hours 0.58% by weight Expansion coefficient when immersed in running water for 24 hours +0.3%

Water absorption when immersed in running water for 24 hours 32% by weight Wet strength when immersed in O 2 running water for 24 hours at 25 C 61 kg/cm EX~PLE 13 A slurry prepared by mixing 168 g of calcium oxide, 10~4S~3 1 156 g of aluminum hydro~id~, 175 g of gyps~m dihydrate,and 750 g of water was reacted for 90 min~tes at 180C in an au'o-clave. Then, after removing water, the product was dried for 5 hours at 50C to provide MSH. The product was ground into a powder finer than 149 ~ mesh~ Moreover, a slurry prepared by mixing 169 g of calcium oxide (finer than 100 mesh), 300 g of zeolite (finer than 325 mesh), and 4.5 liters of water was reacted for 3 hours at 180C in an autoclave under a wet heat condition to provide tobermorite slurry.
Then, a mixture of 30 g of asbestos and 165.6 g of tobermorite slurry obtained above as solid was dispersed finely in water to provide a slurry and to the slurry were added 190 g of MSH, 105 g of gypsum dihydrate, 18 g of glass fibers (chopped strand of 0.64 cm length and 9 ~ diameter) and they were mixed by means of a universal mixer to provide a dispersion. The dispersion was formed into a mat of 20 mm thick. The mat was pressed at a pressure of 10 kg/cm2, 50 kg~cm , or 110 kg/cm2 to provide a plate and the plate was cured for 12 hours at 2~C
under a wet heat condition while preventing the escape of water and dried for 5 hours at 50C to provide a hardened product.
The properties of the product are shown in ~able 6.

The slurry of calcium silicate prepared by the same procedure as above was mixed with 5~ by weight of asbestos and 3~ by weight of the ~lass fibers as described above and the mixture was shaped into a mat, hardened, and dried to provide a hardened plate. The properties of the plate are also des-cribed in the same table.

Bulk Wet Press Specific Bending Bending Water Pressure Gravit~ Strength Strength Absor~tlon (kg/cm~) (kg/cm2) ~kg/cm ) ~weight ~) 110 1.06 142.1 73.0 83 0.78 102.g 65.1 132 0.38 35.4 19.1 209 Comparison Example 1 0.81 87.3 51,2 153 In addition, in Table 6, the wet bending strength and the water absorption were of the case where the sample was saturated with water by being immersed in running water of 25C for 24 hours.
Also, X-ray diffraction chart of the hardened product is shown in Figure 5, which shows the formation of TSH by the peak T and also the existence of a small amount of remaining MSH by the peak of M. In addition, the peak To is for tobermorite.

By following the same procedure as in Examp~e 13, MSH and calcium silicate ~tobermorite) slurry were prepared.
In addition, the bulk specific gravity of the calcium silicate at dry was 0.16. Then, 150 g (as solid) of the calcium silicate slurry was mixed with 15 g of ashestos, 30 g of pulp, and 1,000 g of water and then the mixture was further mixed with 350 g of MSH and 105 g oE gypsum dihydrate to provide a slurry.
: The slurry was formed into a mat of 15 mm thick by means of a paper machine and the mat was pressed at a pressure of 30 kg/cm2 or 105 kg/cm , cured for 3 hours at 80C under a wet heat condition, and dried for 5 hours at 50C to provide a hardened product. The properties of the hardened product of TSH are shown in Table 7.

~ 0~ 83 Bulk Wet Press SpecificBending BendingWater Pressure Gravit~Strength Strength Absorption (kg/cm ) (kg/cm ) (kg/cm2) (weight ~) 105 1.12 138.2 71.5 94 0.83 99.3 68.3 140 . . .
A slurry prepared by mixing 169 g of calcium oxide, 156 g of aluminum hydroxide, 175 g of gypsum dihydrate, and ~O 750 mQ of water was reacted for 90 minutes at 180C in an auto-clave to provide an MSH slurry.
Then, the MSH slurry prepared by the same manner as above was mixed with 86 g of gypsum dihydrate and 4.7 liters of water and the mixture was reacted for 5 hours at 90C to provide a TSH slurry.
Furthermore, a slurry was prepared by mixing 169 g of calcium oxide, 181 g of Toyane silica, and 3.5 liters of water was reacted for 8 hours at 200C in an autoclave to provide a slurry of xonotlite (calcium silicate).
Using each of the raw materials prepared in the above procedures, a slurry having the following composition was prep~red.
Xonotlite slurry 30 g (calculated as solid) TSH slurry 65 g ~ "
MSH slurry 5 g ( "
Asbestos 7 g Glass fibers (as used in Example 13~ 3 g Water 100 mQ
The slurry was formed into a mat of 20 mm thick by means of a paper machine and the mat was pressed at a pressure of 10~ 83 1 10 kg/cm2 and dried for 5 hou~s at ~0C 'o provide a harder.ed plate. The X-ray diffraction chart of the product is shown in Figure 6, which shows that the product was composed of TSH
(T), MSH (M) and xonotlite ~X). The bulk specific gravity and the bending strength of the product were 0.55 and 65 kg/cm2. In addition, the product has superior water resistance than a plaster plate.

A uniform mixture of 168.3 g of calcium oxide, 306.0 g of a-alumina, and 172.1 g of gypsum dihydrate was burned for 7 hours at 1350C to provide a burned product mainly composed of 3CaO.3AQ2O3.CaSO4. The burned product was ground into a powder finer than 149 ~u, the powder ~216 g) was dispersed in 3 liters of water and after adding to the dispersion 112.2 g of calcium oxide, 460 g of gypsum dihydrate, and 5 liters of water, the mixture was reacted for 24 hours at 90C to provide a slurry of TSH.
Using the TSH slurry obtained in the above procedure and the MSH slurry and the xonotlite slurry prepared by the same procedure as in Example 15, the slurry having the following composition was prepared and from the slurry, a hardened plate was prepared as in Example 15.
Xonotlite slurry 60 g (as solid) TSH slurry 30 g ( "
MSH slurry 10 g ~ " ) Asbestos 7 g Glass fibers (as used in Example 13)3 g Water 100 mQ
The specific gravity and the bending strength of the plate are 0.32 and 30 kg/cm2, respectively.

.

1 EX~IPLE 17 A mixed slurry was prepared by mixing the TSH slurry, MSH slurry and xonotlite slurry prepared by the same manner as in Example 15 at the mixing ratio as shown below. A mat of 20 mm thick was prepared from the mixed slurry by means of a paper machine, dried and hardened.
Xonotlite slurry 20 g (as solid) TSH slurry 60 g ( "

MSH slurry 20 g ( "
The specific gravity and the bending strength of the hardened plate were 0.43 and 18 kg/cm , respectively.

Using the xonotlite slurry and the TSH slurry prepared by the same manner as in Example 15 r a mixed slurry having a xonotlite solid content of 20 g and a TSH solid content of 80 g was prepared. The mixed slurry was molded into a plate of 20 mm thick and dried to provide a hardened plate. The bulk specific gravity of the plate was 0.44 and the bending strength thereof was 15 kg/cm2, From Example 17 and Comparison Example 2, it will be understood that the plate prepared usiny a mixture of TSH and MSE is superior to the plate prepared using TSH in bending strength.

A mixture of 222 g of Ca~OH)2 finer than 149 ~u, 224 g of Toyane silica* finer than 325 mesh, and 5.0 liters of water was reacted for 8 hours at 200C in an autoclave to provide an activated tobermorite slurry having a high bulk specific gravity.

~09~5133 1 On the ot~er hand, a mixture of 158 g of calcium oxide, 156 g of aluminum hydroxide, 175 g of gypsum dihydrate, and 750 g of water was reacted for 90 minutes at 180C in ar.
autoclave under a wet heat condition to provide MSH. Then, after adding thereto 172 g of gypsum dihydrate and 9.8 liters of water, the mixture was reacted for 5 hours at 90C under a wet heat condition to provide a TSH slurry.
To a mixture of 280 g (as solid component) of the TSH
slurry and 120 g ~as solid component~ of the tobermorite slurry were added 20 g of asbestos and 12 g of the glass fibers as used in Example 13 and then they were dispersed in 7 liters of water by means of a universal mixer. A mat of 20 mm thick was prepared from the dispersion by a paper machine and divided into 3 pieces of plates. These plates each was pressed at a pressure of 10 kg/cm2, 70 kg/cm2, or 150 kg/cm and dried to provide hardened plates. The properties of the products are shown in Table 8.

Bulk Wet Press SpecificBending Bending Water Pressure Gravit~Strength StrenqthAbsorption**

(kg/cm ) ~kg/cm ) ~kg/cm )~weight %) 150 1.05 110 65.0 86 0.79 90 58.2 129 0.39 23 12.4 210 ** The value when immersed in running water for 24 hours.
In addition, the X-ray diffraction chart of the sample is shown in Figure 7 which shows the product being a mixture of TSH (T) and tobermorite ~To). In addition, a small amount of residue of MSH was confirmed by the peak M.

* Toyane silica is a clay produced in Gifu Prefecture Japan.

~0'~451~3 1 Composition: SiO2 : 99.43?~; Ee~O3 : 0.04%; A~2O3 : 0.44~;
ignition loss: 0.22%; average particle diameter : 5 to 10 ~.

A uniform mixture of 168.3 g of calcium oxide, 306.0 g of a-alumina, and 172.1 g of gypsum dihydrate was burned for 7 hours at 1,350C in an electric furnace to provide a burned product mainly composed of 3CaO.3AQ2O3.CaSO4. The product was ground into a powder finer than 10~ mesh and 216 g of the powder was dispersed in 3 liters of water to provide an aqueous dispersion.
On the other hand, an aqueous dispersion of 112.2 g of calcium oxide and 460 g of gypsum dihydrate in 5 liters of water was prepared.
Both the dispersions prepared above were mixed and the mixture was reacted for 24 hours at 90C to provide a TSH
slurry having a high bulk specific gravity. The slurry was mixed with an equivalent amount of xonotlite slurry prepared by the same manner as in Example 18 and the mixture was hardened as in Example 18. The properties of the hardened plate are shown in Table 9.

The xonotlite slurry prepared by the same manner as in Example 18 was mixed with 5% by weight of asbestos and 3%
by weight of the glass fibers as used in Example 13 and a hardened product was also prepared using the mixture. The properties of the comparative sample are also shown in Table 9.
In Comparison Example 3, however, the pressing pressure was 10 kg/cm .

lO~S~33 1 TA3'~_ 9 Bulk Wet Press Speci,icsending Bending Water Pressure Gra~lty_ StrengthStrength Absorpt~cn (kg/cm ) (kg/cm ) ~kg/cm )(weight ~) 150 1.04108.8 62.4 89 0.7889.9 57.4 130 0.3821.7 11.6 213 Comp. Ex. 0.8187.3 51.2 153 EXAM_PLE 20 10 A mixture of 169 g of calcium oxide finer than 100 mesh, 181 g of Toyane silica finer than 325 mesh, and 3.5 liters of water was heated to 200C for 8 hours in an autoclave to form a slurry of calcium silicate ~xonotlite).
On the other hand, a mixture of 168 g of calcium oxide, 156 g of aluminum hydroxide, 175 g of gypsum dihydrate, and 1 liter of water was heated to 180C for 2 hours in an autoclave to provide a slurry of MSH. Then, the slurry of MSH
was mixed with 350 g of gypsum dihydrate and the mixture was reacted for 3 hours at 85C under a wet heat condition to pro-vide a TSH slurry.

The whole amount of the calcium silicate slurry and the TSH slurry prepared in the above procedures were mixed each other by means of a jet mixer and the mixture filter by suction under compression and dried for 5 hours at 50C to provide a hardened product. By the X-ray diffraction analysis tFigure 8) of the hardened product, TSH tT), calcium silicate (X), and remaining MSH (M) were confirmed.
In addition, the bending strength of the hardened product was 44 kg/cm2 and the water resistance thereof was superior to that of a plaster plate.

lO~?~S83 A mixture of 1~1 g of calcium oxide, 212 g of clinoptilolite and 3.0 liters of water was heated to 180C for 3 hours in an autoclave to provide a tobermorite slurry.
On the other hand, a mixture of 163 g of calcium oxide, 525 g of gypsum dihydrate, 156 g of aluminum hydroxide, and 2 liters of water was heated to 95C for 6 hours to provide a TSH slurry.
Both the slurries were mixed each other by means of a jet mixer, filtered by suction under compression, and dried for 12 hours at 50C to provide a hardened product. The X-ray diffraction chart of the product is shown in Figure 9 which shows the peaks of TSH, tobermorite (Tb3, and MSH. In addition, the bending strength of the hardened product was 36 kg/cm2 and the water resistance thereof was superior to that of gypsum plate.

- A mixture of 180 g of calcium oxide (extra pure reagent), 110 g of activated alumina ~extra pure reagent), 170 g of gypsum dihydrate (extra pure reagent), and 2,500 g of water was reacted for 180 minutes at 170C in a five liter h gh-pressure reaction vessel to provide MSH. The free gypsum con-tained in the product was 0.32%.
Then, 337 g of gypsum dihydrate was added to the MSH
prepared above and then the mixture was further uniformly mixed with 30 g of starch (tapioca), 12 g of asbestos, 6 g of the glass fibers as used ln Example 13, and 2,000 g of water and then using the resultant mixture, a mat of 10 mm thick was prepared by a paper machine. The mat was cured for 4 hours in a chamber maintained at a temperature of 60C and a humidity of - ~o 10'~'~5e~3 1 100~ R.H. and dried tor 5 hou-s a. 45~ to provide a hardened product of TSH and starch contai~ing less free gypsum (1.1~ ~-the hardened product). By the X-ray diffraction analysis o,~ the product, the formation of TSH was confirmed. The chart of the X-ray diffraction is shown in Figure 10 in which the peak T
shows TSH, and the peak C shows gypsum dihydrate.

The MSH prepared by the same manner as in Example 22 was uniformly mixed with 250 g of gypsum dihydrate, 15 g of polyvinyl alcohol ~number average molecular weight of 1700, dissolved in 150 g of water), 4,000 g of water, 15 g of asbestos, and 6 g of polypropylene fihers of 12 mm length and 20 ~u diameter and a plate was molded from the mixture. The plate thus formed was cured for 6 hours under the conditions of 40C and 100%
R.H. The plate was then dried for 5 hours at 45C to provide a hardened product of MSH, TSH, and polyvinyl alcohol. In addition! the content of free gypsum was 0.3% based on the weight of the hardened product.

The X-ray diffraction chart of the product is shown in Figure 11, in which the peak M shows MSH.
EXAMPLE_24 A mixture of 633 g of MSH prepared by the same manner as in Example 22 and 80 g of gypsum dihydrate was further mixed with 13 g ~as solid component) of an acrylic resin emulslon, Dianal Lx-200 ~a trade name, produced by Mitsubishi Rayon ~o., Ltd.), 430 g of water, and 25 g of pulp and from the mixture a plate of 10 mm thick was molded. The plate was then cured for 3 hours in the atmosphere of 60C and 100~ R.H.
and dried for 7 hours at 45C to provide a hardened product.

~ 41 -109 ~583 1 The X-ray diffraction cha-t o- .he ?roduc' is shown in Fi ure 12.
In addition, the content OL free gypsum was 0.8% based on the weight of the hardened product.

By the same manner as in Example 22, a hardened pro-duct of TSH was prepared without adding, in this case, starch.
The content of free gypsum in the hardened product was 0.24%.

From a uniform mlxture of S00 g of TSH, 6 g of asbestos, 3 g of glass fibers, and 1,000 g of water, a mat of 10 mm thick was formed by a paper machine. The mat was cured for 4 hours in a chamber maintained at a temperature of 60C
and a humidity of 100% R.H. and dried for 5 hours at 45C to provide a hardened product.

The same procedure as in Comparison Example 5 was followed while adding, in this case, 15 g of starch to provide a hardened product.
The results of Examples 22, 23 and Comparison Examples

4 - 6 are shown in Table 10.

Bending Strength Choking (kg/cm2 ) Example 22 109 none Example 23 120 none Example 24 82 none Comparison Example 4 61 observed 30 Comparison Example 5 32 observed Comparison Example 6 53 none 1094S~3 1 Ex~LE 25 After mi~ing 170 parts by weight of calcium oxide (co~ercially available reagent), 102 parts by weight of activated alumina (commercially available reagent), and 172 parts by weight of gypsum dihydrate (commercially available reagent) for 30 minutes by means of a vibration mill, 350 parts by weight of water was added to the mixture followed by mixing to provide a uniform slurry. The slurry was reacted for 100 minutes at 180C in an autoclave to provide MSH.
The MSH slurry (solid 300 parts) thus obtained was mixed with 22 parts of starch, and 300 parts of water by means of a mixer. The slurry was poured in a mold of 25 mm x 100 mm x 10 mm to provide a coagulated shaped material. The product was cured for 6 hours at 50C and then dried for 20 hours at 50C. The X-ray diffraction chart of the product is shown in Figure 13, in which the peak M shows MSH.

A hardened product was prepared by following the same procedure as in Example 25 except that starch was not added to MSH. The hardened product was allowed to stand for 30 days in the air. The X-ray diffraction chart of the product is shown in Figure 14, in which the peak S shows gypsum and the peak C
shows calcium carbonate.

In 500 parts by weight of water was dissolved 64.8 parts of the crystal of aluminum sulfate (AQ2(SO4)3.17H2O) and after adding to the solution 44.5 parts of calcium hydroxide and 600 parts of water, the mixture was reacted for 60 minutes at 25 C to provide a slurry of TSH.

l By follot~ing the sa e procedure as ln Example 2~
using a mixture o~ the TSH slurry (solid component 800 parts) and ll parts o~ polyvinyl alcohol (number average ~olecular weight of 1700), a hardened product was obtained.

The same procedure as in Example 26 was followed except that polyvinyl alcohol was not added to TSH to provide a plate of a hardened product. The plate was allowed to stand for 30 days in the air. The X-ray diffraction chart of the product is shown in Figure 15, in which the peak T shows TSH.
Furthermore, the peaks of gypsum (S) and calcium carbonate (C), which were not observed before the product was allowed to stand in the air, were observed.

__ The MSH and TSH prepared by the same manners as in Examples 25 and 26, respectively, were mixed at a ratio of l : l as the weight of solid contents.

The mixed slurry (300 parts by weight of solid con-tent) was mixed with 15 parts by weight of an acrylic resin emulsion, Dianal Lx-400 (a trade name, made by Mitsubishi Rayon Co., Ltd.) and using the composition thus prepared, a plat~
of hardened product was prepared by the same manner as in Example 25. The X-ray diffraction chart of the product is shown in Figure 16, in which the peak S shows gypsum present in the product as an impurity.

C~MPARISON EXAMPLE 9 By following the same procedure as in Example 27 except that the acrylic resin emulsion was not used, a hardened product was prepared. The product was allowed to stand for - ~4 -10945~3 1 30 days in the air. The Y-r~y di-frac~ion chart of the produc is shown in Figure 17, in which the peak M' shows the deh~dr~~e of MSH.
The initial bending strength of the hardened proaucts prepared in Examples 25 - 27 and Comparison Examples 7 - 9 and also the bending strength of them after allowing to stand for 30 days in the air were measured. The results are shown in Table 11.

In addition, the results of the X-ray diffraction analysis of the hardened products show besides the peaks of TSH and MSH, gypsum, the peaks of calcium carbonate, and the dehydrate of MSH, which show the modifications of TSH and MSH
by decomposition.

Initial Initial Amount Bending of Free Stren~th Gypsum After 30 days in air (kg/cm ) (~) (A) (B) (C) Example 25 48 0.22 48 0.35 none Comparison Example 7 15 0.1513.9 3.5 observed Example 26 41.4 0.31 31 0.36 none Comparison Example 8 13.8 0.13 7.6 3.3 observed Example 27 28.2 0.30 15.8 0.65 none Comparison Example 9 13.6 0.13 6.5 3.6 observed ~A): Bending strength by kg/cm2 (B): Amount of free gypsum by weight %
(C): Surface choking After mixing 170 parts by weight of calcium oxide lQ~?~5~3 1 (commercially available reagent), 102 par.s o' activated alumi~a (commercially available reagent), and 172 parts of gypsum dihydrate (commercially available reagent) for 30 minutes by means of a vibration mill, 350 parts of water was added to the mixture to provide a uniform slurry. The slurry was reacted for 100 minutes at 180C in an autoclave to provide MSH.
Then, a slurry prepared ~y mixing 169 parts of calcium oxide (commercially available reagent), 181 parts of Toyane silica, and 3,500 parts of water was reacted for 8 hours at 200C in an autoclave to provide a slurry of calcium silicate (xonotlite).
Then, the MSH slurry ~solid component 210 parts) and the calcium silicate slurry (solid component 90 parts) thus prepared were mixed uniformly with 20 parts of starch and 280 parts of water to provide a mixed slurry. From the slurry, a mat of 25 mm x 100 mm x 10 mm was prepared by molding and the mat thus molded was cured for 6 hours at 50 C under a wet heat condition and dried for 10 hours at 50 C. The X-ray diffraction chart of the product is shown in Figure 18, in which the peak M
shows MSH and the peak X shows calcium silicate (xonotlite).

By following the same procedure as in Example 28 except that starch was not added to the mixture of MSH and calcium silicate, a hardened product was prepared. The product was allowed to stand for 80 days in the air. The X-ray diffraction chart of the product is shown in Figure 19, in which the peak S shows gypsum and the peak C shows calcium car~onate.

3~ In 500 parts by weight of water was dissolved 64.8 parts of the crystal o, aluminum sulfate (AQ2(SO4)2.17H2O) ~O't~S~3 1 and after adding thereto ~A,5 -a~s or calci~. hydroxide ar~
600 parts of water, the mix.ure was reacted for 60 minutes a' 25 C to provide a slurry of TSH.
A mixture of the TSH slurry ~solid component 300 parts by weight) and the calcium silicate slurry ~solid component 130 parts) was mixed with 11 parts by weight of polyvinyl alcohol (number average molecular weight of 1700) and then by treating the resultant mixture as in Example 28, a plate of a hardened product was obtained.

COMPARIS~N EXAMPLE 11 _ By following the same procedure as in Example 29 except that polyvinyl alcohol was not added to the mixture of the TSH slurry and the calcium silicate slurry, a plate of hardened TSH-calcium silicate product was o~tained. The X-ray diffraction chart of the product after allowing to stand for 30 days in the air is shown in Figure 20, in which the peak T
shows TSH. In the chart,the peaks of gypsum (S) and calcium carbonate (C) which were not observed in the chart of the product before the product was allowed to stand are observed.

The MSH slurry prepared in Example 28 and the TSH
slurry and the calcium silicate slurry prepared in Example 29 were mixed at a mixing ratio of 1 : 1 : 1 by weight of solid component. The mixed slurry (solid component 300 parts by weight) was mixed with 15 parts by weight (as solid component) of an epoxy resin emulsion, ~podite EMEB-400 (a trade name, made by Showa Kobunshi K.K.). By following the same way as in Example 2 using the composition thus prepared, a plate of hardened product was prepared. The X-ray diffraction char~ of the 10'~ ~83 1 product is sho~ in Figure 21, in which the peak S shows gyps~

present in a small amount as an impurit~.
COMPARISON EXZ~IPLE 12 By following the same procedure as in Example 30 except that the epoxy resin emulsion was not used, a plate of hardened product was prepared. The X-ra~ diffraction chart of the product after it was allowed to stand for 30 days is shown in Figure 22, in which the peak M' shows the dehydrate of MSH.

The initial bending strength and the bending strength lQ
after allowing to stand for 30 days in the air were measured about the hardened products prepared in Examples 28 - 30 and Comparison Examples 10 - 12, the results being shown in Table 12.
In the X-ray diffraction charts, the peaks of gypsum, calcium carbonate, and the dehydrate of MSH are observed besides the peaks of TSH, MSH, and calcium silicate and they show that the compositions of the hardened products were denatured.

Initial Initial Bending Free After Allowing to Stand StrengthGypsum for 30 Days in the Air ~kg/cm 3 (%) (A) (B) (C~
Example 28 32.8 0.17 32.6 0.38 none Comparison Example 10 19.5 a . lQ 18.3 2.70 observed Example 29 23.3 0.23 23.1 0.44 none Comparison Example 11 16.7 0.08 6.2 2.4 observed Example 30 22.5 0.15 12.4 0.49 none Comparison Example 12 11.2 0.11 5.8 2.6 observed After mixing 170 parts by weight of calcium oxide ~ ds~ ~

10~583 1 (co~mercially availabl~ re?~gent), 102 parts of activated alu~..ina (co~mercially available re~gent), and 172 parts by weight o~
gypsum dihydrate (co~mercially available reagent) for 30 minutes by means of a vibration mill, 350 parts by wei.ght of water was added to the mixture to provide a uniform slurry. The slurry was reacted in an autoclave for 100 minutes at 180C under wet heat condition to provide MS~.
Then, a slurry was prepared by mixing 169 parts by weight of calcium oxide (commercially available reagent), 181 parts of Toyane silica, and 3,500 parts of water and was reacted in an autoclave for 8 hours at 200C under a wet heat condition to provide a slurry of calcium silicate (xonotlite).
The MSH slurry ~solid component 210 parts) and the calcium silicate slurry (solid component 90 parts) thus prepared were mixed with 3 parts of coconut oil ~commercially available reagent) and 280 parts of water and they were uniformly mixed by means of a mixer. Using the slurry thus prepared, a plate of 25 mm x 100 mm x 10 mm was molded. The plate was then cured for 8 hours at 50C under a wet heat condition and dried for 10 hours at 50C. For determining the carbonation speed of the solid plate composition (hardened product) was forcibly car-bonated at 40C and 100% humidity using 100% carbon dioxide gas at a rate of 300 mQ/min.

By following the same procedure as in Example 31 except that coconut oil was not added, a hardened solid com-position was prepared. The product was then carbonated as in Example 31.

3~ EXAMPLE 32 -In 500 parts by weight of water was dissolved 64.8 - ag -

5~3 1 parts by weight of the crys.~1 o- alu.~inum sul~ate (AQ2(so~)3.l7~l2o) ~nd then ~.5 parts of calcium hydroxide and 600 parts of water were added to the solution. The mixture was reacted for 60 minutes at 25 C to provide a TSH slurry.
To a mixture of the TSH slurry ~solid component 300 parts) and the calcium silicate slurry (solid component 130 parts) prepared in the aforesaid procedures was added 6 parts by weight of aluminum stearate and using the resultant mixture, a plate of hardened solid composition was prepared by the same manner as in Example 31.

COMPARISON EXP~IPLE 14 . .
By following the same procedure as in Example 32 except that aluminum stearate was not used, a plate of a hardened solid product was prepared. The product was also forcibly carbonated.

The MSH slurry, the TSH slurry, and the calcium silicate slurry prepared in Examples 31 and 32 were mixed at a mixing ratio of 1 : 1 : 1 by solid weight and the mixed slurry (solid component 300 parts) was mixed with 3 parts by weight of palmitic acid. Using the slurry, a plate of solid compo-sition was prepared by the same manner as in Example 31. The plate was also carbonated as in Example 31.

_ By following the same procedure as in Example 33 except that palmitic acid was not used, a solid composition was prepared and then forcibly carbonated as in the same Example.

The properties of the plate produc~s prepared in the lO~l~SR3 1 above examples and co~paris^n -.~amples are sho~.~n in Table 13.

T.~BLE 13 Carbonation l~ater Period Absorption Bending Strength (hr.) (~) ~kg/cm2) Initial After Example 31 5 0.8 24.5 21.5 Comparison Example 13 1 4.2 20.0 12.0 Example 32 3 1.1 21.5 18.5 Comparison Example 14 1 4.4 16.7 10.0 Example 33 3 1.0 19.1 16.1 Comparison Example 15 1 4.1 15.9 9.5 In the above table, the carbonation period of time shows the period until the peak of TSH or MSH disappears on the X-ray diffraction chart by the carbonation and the water absorption is shown by the weight increase o~ the sample after it is allowed to stand for one hour at 40C and 100~ R.H.

2 ExAMpLE 34 o In 500 mQ of water was completely dissolved 64.8 g of the crystal of aluminum sulfate (AQ2~SO4)3.16-18H2O) and the solution was placed in a three liter flask equipped with a stirrer.
On the other hand, 44.5 g of calcium hydroxide was uniformly dispersed in 600 mQ of water and the dispersion was added to the aforesaid aqueous aluminum sulfate solution with stirring, whereby the temperature of the aqueous solution incre sed from 19C to 23.6C after 5 minutes. The mixture was reacted for 60 minutes at 25C with stirring and the reaction 10~14583 1 product was recovered by filt~ation and dri~d ror 6 hours at 5G C to provide TSH.
Furthermore, 3 g of asbestos was dispersed in 500 m2 of water and opened by means of a mîxer ~with stirring for one minute at a rate of 800 r.p.m.). Thereafter, 60.3 g of the TSH prepared above and 400 mQ of water were further added to the dispersion in the mixer and the mixture was stirred vigorously for 20 seconds and after adding further to the mixture 3 g of ~ class glass fibers (chopped strand of 0.6 cm length 1~ and 9 ~ diameter), the resultant mixture was further mixed for 10 seconds by means of the mixer to open the glass fibers and to provide a slurry.
Then, from the slurry, a mat was formed by means of a hand-type paper machine having a filter area of 70 mm x 80 mm and was pressed by means of a hand press until the thickness became 10 mm. The pre-shaped product thus obtained was car-bonated in a carbonation cell while preventing the escape of water at 80 C and 100~ R.H. by supplying carbon dioxide gas at a rate of 300 mQ/min. After continuing the carbonation reaction for 9 hours under these conditions, the product was withdrawn from the carbonation cell and dried for 3 hours at 50C. The dried product was cut out into a sheet of about 70 mm x 20 mm to provide a sample for measurement of the bending strength. Twenty sheets of such samples were prepared and the mean values of the bending strength and bulk specific gravity of them were 87 kg/cm2 and 1.03, respectively.
In addition, the comparison sample prepared by the same manner as above without using glass fibers showed a bending strength of 18.5 kg/cm2 and a bulk specific gravity of 1.03.

10'34583 1 ~hen the ~ard~ d ~odu_t -~ras gYou~d and subjecte~
to an ~-ray diffraction analysis, the peak of TSH was not o~served. Also, when the powder of the hardened product thus ground was d'spersed in water, the pH of the dispersion was 7.2 A mixture of 80.6 g of calcium oxide (100 meash sieve passed), 82.6 g of gypsum dihydrate ~extra pure reagent), 74.8 g of aluminum hydroxide (Sumitomo Aluminum Hydroxide C-31, made by Sumitomo Chemical Company, Limited), and 382 mQ of water was placed in a one-liter autoclave equipped with a stirrer and after raising the temperature of the mixture to 180C over a period of about one hour, the mixture was reacted for 2 hours at 180 C with stirring at a rate of 150 r.p.m. and then the reaction product was cooled and withdrawn to provide MSH.
Then, 3 g of asbestos was dispersed in 500 mQ of water and opened by means of a mixer ~with stirring for one minute at a rate of 800 r.p.m.) and after adding 25.0 g of the MSH

prepared above to the dispersion in the mixer together with 13.5 g of gypsum dihydrate and 400 mQ of water, the resultant mixture was stirred vigorously for 20 seconds. Then, 1.5 g of glass fibers was further added to the mixture and opened with stirring for 10 seconds in the mixer to provide a slurry.
A mat was prepared from the slurry as in Example 34, cured for 15 to 2 hours at 20 to 90C under a wet heat condition, and then carbonated in a carbonation cell while preventing the escape of water from the sample. The carbonation condition was same as in Example 34. The bending strength of the shaped product was 90 kg~cm (bulk specific gravity 1.02).

~0~ 33 1 EXA~PLE 36 A mixture of 3 g of asbestos and 500 mQ o~ water was stirred for one minute by means of a mixer and after further adding to the mixture 30 g of TSH prepared in Example 35 and 15 g of calcium hydroxide, the resultant mixture was further stirred for 20 seconds. To the mixture was further added 1.5 g of glass fibers as used in Example 34 followed by stirring for 10 seconds to provide a slurry. Using the slurry a hardened product having a bulk specific gravity of 1.04 and a bending strength of 86 kg/cm was prepared by the same manner as in Example 34.

Using the TSH prepared as in Example 34, a hardened shaped product having a low ~ulk specific gravity was prepared by making mat, shaping, and carbona-ting the mixture having the following composition under the same conditions as in Example 34.
TSH 28.0 g Asbestos 1.5 g (Canadian chrysotile 6D) Glass fibers 0.9 g The bulk specific gravity and the bending strength of the hardened product were Q.45 and 28 kg/cm2,respectively.

A mixture of 180 g of calcium oxide, 110 g of activated alumina, 170 g of gypsum dihydrate, and 2,500 g of water was reacted in a five-liter autoclave at 170C for 180 minutes to provide MSH. In this case, the proportion of unreacted gypsum was 0.35% by weight.
Then, 337 g of gypsum dihydrate was added to the MSH

10!~4S~3 1 thus prepared and a~ter fur.her adding thereto 20 g of iso-phthalic acid, 48 g of asbestos, 19 g of glass fibers, and 1,000 g of water, they ~vere stirred to provide a uniform mixture.
Then, the mixture was poured in a mold of 300 mm x 300 mm x 10 m~
and coagulated therein~ The shaped product was then cured for 3 hours at 40C and 100% R.H. and dried at 45C to provide a solid shaped product.

By following the same procedure as in Example 38, MS~ was prepared. To 622 g of the MSH were added 337 g of gypsum dihydrate, 1,000 g of water, 48 g of asbestos, and 19 g of glass fibers and by treating the resultant mixture as in Example 38, a shaped product was prepared.

To 622 g of MSH were added 337 g of gypsum dihydrate, 10 g of terephthalic acid, and 1,000 g of water and then the mixture was shaped as in Example 38. The shaped product was cured for 3 hours at 60C under a wet heat condition.

By following the same procedure as in Example 39 except that terephthalic acid was not used, a shaped product was prepared.

To 622 g of MSH prepared by the same manner as in Example 38 were added 337 g of gypsum dihydrate, 5 g of phthalic anhydride, and ~,000 g of water and they were mixed uniformly.
From the mixture a mat of 300 mm x 300 mm was prepared by a hand-type paper machine and cured for 3 hours at 75C and 100%

~ 55 -109~5F~3 1 R.~. under a ~et hea. co~dit~on. T~e shaped material was 'her.
dried at 45C.

COMPARISON E~MPLE 18 By following the same procedure as in Example 40 except that phthalic anhydride was not used, a shaped product was prepared.
The properties of the hardened products of TSH prepared in the aforesaid examples and comparison examples are shown in Table 14. Also, the amount of residual gypsum in each product was measured every period shown below ~by JIS KO 102-1964 Absorptiometric Method*) and the results are also shown in the table. By the results, the reac ion accelerating action of the aromatic carboxylic acid was confirmed.
* The sample containing SO4 is added into the solution of glycerin and NaCQ. BaCQ2 is added into the solution and SO4 changes to BaSO4. The nuddiness is measured by absorptiometric method and the amount of SO4 is determined.

~O 30 60 80 120 180 Bending MinMin Min Min Min Strength _ (~)(%) (%) ~%) ~%) (kg/cm2) Example 38 8.4 5.8 4.2 3.8 3.6 80 Example 39 3.1 1.9 1.6 1.3 1.3 89 Example 40 0.9 0.3 0.3 0.3 0.3 93 Comparison Example 16 15 11.5 9.2 7.1 6.3 71 Comparison Example 17 5.8 3.1 2.6 2.3 2.1 78 Comparisor.
Example 18 2.2 1.4 1.1 1.0 1.0 83 10~5~33 1 EX~IP~E 41 A mixture o~ ~4.2 g of calclum oxide, 46.8 g of boemite, and 86.1 g of gypsum dihydrate, each being a powder passing 100 mesh sieve was burned for 2 hours at 1,300C and then allowed to cool under room temperature to provide a solid -solution of C4A3S. The product was pulverized by means of an iron-made mortar and then by means of crusher and further a sample mill. The powder of the sample product passing through a 100 mesh sieve was collected.
To 800 mQ of water was added 7.2 g of Canadian chrysotile 6D and the mixture was stirred for one minute by means of a high-speed rotary mixer to open the chrysotile. To the mixture were added 63.1 g of the powder of C4A3S prepared in the above step and 35.6 g of gypsum dihydrate followed by further stirring for 20 seconds and after adding thereto 4.3 g of glass fibers (chopped strand), the mixture wàs stirred for 10 seconds to provide a uniform slurry.
Then, from the slurry thus prepared, a sheet was prepared by means of a hand-type paper machine having a filter area of 12 cm x 12 cm and pressed by means of a hand press until the thickness of the sheet became 1 cm. The sheet was then cured for 4 hours at 40C and 100% R.H. under a wet heat condition and dried to give a hardened shaped product. A same piece was cut out of the sample and the bending strength and bulk specific gravity were measured about the sample piece.
The bulk specific gravity and the bending strength of the hardened product were 1.02 and 98 kg/cm . When the hardened product was immersed in running water for 24 hours and then the bending strength was measured. The bending strength thereof was 62 kg/cm2.

10~i~5~33 1 E.Y~IPL~ 42 Using the slur-y prepared as in Example 41, a sheet was prepared by means of a hand-type paper machine while changing the feeding amount of the slurry and the pressing pressure. Thus, hardened products having various bulk specific gravities were obtained. The bulk specific gravities and bending strengths of the hardened products are shown in the following table.

Bulk Bending Strength at Specific Bending Saturation after Gravity Strength Immersed in Running 2 Water for 24 Hours (kg/cm ) 2 (kg/cm ) 0.9~ 8g 57.9 0.81 77 49.8 0.73 62 40 Hardened products having various bulk specific 2~ gravities were prepared by the same manner as in Example 41 using the slurry having the following composition shown in Table 16 while changing the feeding amount of.the slurry to a hand-type paper machine and the pressing pressure. The bending strengths of the products are shown in Table 17.

Raw Material Amount 4 3 42.5 g Gypsum dihydrate 24.0 g Xonotlite slurry 43.2 g Glass fibers 4.3 g Asbestos (Canadian chrysotile 6D) 7.2 g Water 800 m~

10!945~3 1 In additio~, calci~m al llcate or xonotlite used in this example was prepared ~y the following manner. That is, 33.8 g o~ calcium oxide (passing a 100 mesh sieve) and 36.2 g of Toyane silica (passing a 325 mesh sieve) were uniformly dispersed in 700 mQ of water and the dispersion was subjected to a hydrothermal treatment in a one-liter autoclave equipped with a stirrer for 8 hours at a reaction temperature of 200C
and pressure of 14.8 kg/cm2 gauge with stirring at a rate of 100 r.p.m., whereby the calcium silicate or xonotlite slurry 10 was prepared.

Bending Strength at Bulk Saturation after Specific Bending Immersed in Running Gravity Strength Water for 24 Hours at (kg~cm ) 25C 2 (kg/cm ) 1.02 106.6 67.8 0.91 ~8.2 57.2 0.83 84.4 52.9 0.72 71.3 44.7 0.64 58.1 36.5 A mixture of 64.8 g parts of the crystal of aluminum sulfate (AQ2(SO4)3.17H2O), 1,000 parts of water, and 44.5 parts of calcium hydroxide was reacted for 60 minutes in a reaction vessel with stirring. The temperature of the system increased from 19C to 23C after 5 minutes since the mixing and the reaction system was maintained at the same temperature until the reaction was over. The reaction product obtained was confirmed to be TSH by X-ray diffraction.
The product was filtered, dried, and then heated for 10~-~S1~3 1 5 hours by means o~~ a dr~er o~ 12~C to pro~iide the dehyd~ate of TSH, which was also confirmed by X-ray diffraction (Figure 23) and the weight loss by burning (the peak of TSH was not observed).
To the dehydrate of TSH thus prepared were added 80 parts of asbestos and 5,000 parts of water and the mixture was stirred by means of a high-speed mixer to open the asbestos to provide a slurry, from which a sheet was prepared by means of a paper machine. The sheet was pressed until the thickness thereof became 6 mm and dried for 5 hours at 40C to provide a hardened shaped product. The product was confirmed to be TSH by X-ray diffraction ~the same X-ray diffraction chart with Figure 4 was obtained). The bulk specific gravity was 0.82, the bending strength was 62 kg/cm2.

A mixture of 168 parts by weight of calcium oxide, 156 parts of aluminum hydroxide, 175 parts of gypsum dihydrate, and 750 parts of water was reacted in an autoclave for 90 minutes at 180C under a wet heat condition to provide MSH.

To the product were added 172 parts of gypsum dihydrate and 9,300 parts of water and the mixture was reacted for 5 hours at 90C under a wet heat condition. The product obtained was confirmed to be TSH by X-ray diffraction analysis.
Then, by heating 500 parts by weight of the powder of TSH prepared in the above step for 5 hours at 80C, the dehydrate of TSH was obtained. To the product were added 15 parts of pulp, 15 parts of asbestos, and 1,000 parts of water and they were mixed for 3 minutes by means of a high-speed mixer to open the pulp and asbestos and then 4,000 parts of water was further added to the mixture to provide a slurry.

By forming a sheet from the slurry, pressing the sheet, and ~I0~'-45F~3 1 hardening and dryi~g the ~1~ e bv the sa~,e manner as in Example 44, an aimed hardened product was obtained.

E~MPLE 46 Calcium oxide (extra pure reagent, 100 mesh under), aluminum sulfate (AQ2(S04)3.16H20) (extra pure reagent), and Toyane silica (325 mesh under) were used as the raw materials.
(a) A mixture of 130 parts by weight of calcium oxide, 478 parts by weight of aluminum sulfate, and 1,000 parts of water was reacted in a reaction vessel for 60 minutes with stirring. The temperature of the mixture raised from 19C to 60C after 5 minutes since the mixing and the reaction system was maintained at the temperature until the reaction was over.
The reaction product was confirmed to be TSH by X-ray diffraction.
After filtering and drying the product, 250 parts of the product was heated for 5 hours by means of a dryer of 80C
to the dehydrate of TSH, which was confirmed by the heating weight loss and the X-ray diffraction. (The peak of TSH was not observed.) (b) A mixture of 169 g of calcium oxide, 181 g of silica, and 3,500 g of water was reacted in an autoclave for 4 hours at 170C under a wet heat condition to provide a tobermorite slurry. The product was filtered and dried to provide calcium silicate.
After mixing the dehydrate of TSH thus prepared, 100 parts by weight of calcium silicate, 30 parts of asbestos tCanadian chrysotile 6D), and 5 g of glass fibers (chopped strand of 0.65 cm length and 9 ~u diameter, made by Nitto Boseki K.K.) by means of a jet mixer for 3 minutes while opening the glass fibers and asbestos, 4,000 parts by weight of water was 5t~3 1 added to the mixture to ?ro~de a slurry. Fro~ the slurr~, ~
sheet t~as prepared by r,eans of a paper machine and pressed un_~l the thickness of the sheet became 11 mm. The plate was dried for 2 hours at 100C and then for 5 hours at 40C. The X-ray diffraction and other properties of the product were measured.
The X-ray diffraction chart of the product showed the presence of the peaks o~ TSH and calcium silicate. The bending strength and the bulk specific gravity of the product were 15 kg/cm2 and 0.30, respectively.

A mixture of 250 g of the dehydrate of TSH prepared by the same manner as in Example 4~, 100 g of calcium silicate, and 1,100 g of water was mixed uniformly by means of a jet mixer to provide a slurry. The slurry was shaped in a mold and hardened. The product was dried for 2 hours at 100C and then for 5 hours at 40C. The bending strength and the bulk specific gravity of the hardendd product were 25 kg/cm2 and 0.50.

To 300 g of the dehydrate of TSH and 50 g of calcium silicate prepared as in Example 46 was added 1,100 g of water and they were uniformly mixed by means of a jet mixer to provide a slurry. The slurry was shaped in a mold and hardened. The product was then dried for 2 hours at 100C and then for 5 hours at 40C. The bending strength and the bulk specific gravity of the hardened product were 40 kg/cm2 and 0.65, respectively.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

- 6~ -

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A hardened product composition comprising:
(a) a member selected from the group consisting of 3Cao.A?203.CaSO4.12H2O, 3CaO.A?203.3CaS04.3l-32H20 and a mixture of them, and (b) calcium silicate, wherein the proportion of said calcium silicate to the member selected from the group consisting of 3Ca0.A?203.CaS04.12H20, 3CaO.A?203.3CaS04.31-32H20 and a mixture of them is from 0.5/9.5 to 9/1 by weight.

2. The composition as claimed in claim 1 wherein said composition contains at least one of a filler, a pigment, and a lubricating agent.

3. The composition as claimed in claim 1 wherein a mixing ratio of 3Ca0.A?203.CaS04.12H20 to 3CaO.A?203.3CaS04.31-32H20 is 0.01 to 4 : 1 by mole ratio.

4. A process of producing a composition for hardened material which comprises mixing a first material selected from the group consisting of 3Ca0.A?203.CaS04.12H20, 3Ca0.A?203.3CaS04.
31-32H20 and a mixture of them, with calcium silicate, as a reinforcing agent, during or after the preparation of said first material at any step, wherein the proportion of said calcium silicate to the first material selected from the group consisting of 3Ca0.A?203.CaS04.12H20, 3Ca0.A?203.3CaS04.31-32H20 and a mixture of them is from 0.5/9.5 to 9/1 by weight.

5. The process as claimed in claim 4 wherein said 3CaO.A?2O3.CaSO4.l2H2O is prepared by reacting a CaO component, and A?2O3 component with a CaSO4 component in the presence of water at temperatures of 100 to 200°C.

6. The process as claimed in claim 4 wherein said 3CaO.A?2O3.3CaSO4.3l-32H2O is prepared by reacting a member selected from the group consisting of 3CaO.A?2O3.CaSO4.l2H2O, 3CaO.3A?2O3.CaSO4, 3CaO-A?2O3-6H2O, and a mixture of CaO4 component and an A?2O3 component with a CaSO4 component in the presence of water at a temperature of lower than 120°C.

7. A process as claimed in claim 4 wherein 3CaA?2O3.3CaSO4.3l-32H2O is used, said process further comprising the steps of firstly dehydrating the 3CaA?2O3.3CaSO4.3l-32H2O to 3CaA?2O3.3CaSO4.nH2O, wherein n is a number of 0 to 31, before mixing with the calcium silicate, and secondly adding water before hardening the mixture.

8. The process as claimed in claim 7 wherein n is a number of 10 to 20.

9. The process as claimed in claim 6 wherein 3CaO.A?2O3.CaSO4.l2H2O is reacted with CaSO4 component and water in the presence of a member selected from the group consisting of an organic compound having COOH group and OH group, calcium oxide, calcium hydroxide, and a protective colloid.

10. The process as claimed in claim 6 wherein 3CaO.A?2O3.CaSO4.l2H2O is reacted with a CaSO4 and water in the presence of an aromatic carboxylic acid represented by the general formula or an anhydride thereof:

Claim 10 continued:
wherein n represents an integer from 1 to 4; R represents or

11. A process as claimed in claim 4 said process comprising the further step of carbonating the hardened material.