JP4559537B1 - Method for producing calcium silicate molded body - Google Patents

Abstract

The present invention provides a method for producing a calcium silicate molded body capable of sufficiently preventing discoloration without incurring equipment costs.
The present invention relates to a calcium silicate for autoclaving a semi-cured product obtained by semi-curing a raw slurry obtained by adding water to a solid component mainly composed of a siliceous raw material and a calcareous raw material and kneading them. The present invention relates to a method for producing a molded body. In the present invention, one or more glycerins selected from glycerin, diglycerin, and polyglycerin having a polymerization degree of 3 or more are applied to the surface of the semi-cured product, or glycerin is applied to a solid component, water or a raw material slurry. , Diglycerol, and one or more glycerols selected from polyglycerol having a polymerization degree of 3 or more are mixed.
[Selection figure] None

Description

  The present invention relates to a method for producing a calcium silicate molded body.

  The calcium silicate molded body is, for example, a semi-cured body obtained by adding water to a solid component mainly composed of a siliceous raw material and a calcareous raw material to knead to produce a raw material slurry, and semi-curing the raw material slurry. Is produced by autoclaving.

  In the manufacturing method described above, after producing a predetermined number of semi-cured bodies, these semi-cured bodies are autoclave-cured collectively. It is made to stand by in an atmospheric condition until several semi-hardened bodies are obtained.

  When these semi-cured bodies are cured in an autoclave to produce a calcium silicate molded body (also referred to as a “molded body”), the portion that has been in contact with air before the curing of the autoclave is changed to a different color from the other portions. May cause uneven color.

  As described above, since the autoclave curing is performed after obtaining a predetermined number of semi-cured bodies, the waiting time in the semi-cured body state varies. As the waiting time increases, the degree of discoloration of the molded body increases. Therefore, a difference in color tone due to a difference in the degree of discoloration may occur between a plurality of molded articles obtained after autoclave curing.

  Therefore, when discoloration occurs in a calcium silicate molded product, color unevenness in a single product or a difference in color tone between multiple products may occur, resulting in a decrease in value, or when the degree (degree) of discoloration is significantly large Since defective products are generated, there is a problem that the yield of product manufacturing is deteriorated.

  As a method for preventing the occurrence of discoloration of the calcium silicate molded product, for example, in Patent Document 1, before the autoclave curing process, the air contact surface of the semi-cured product is coated with a paint having the same color tone as the molded product as a product. There has been proposed a method for preventing discoloration of a calcium silicate molded body by forming a protective layer that prevents the influence of outside air contact by applying product waste of an ALC panel. However, in the method of applying the paint, it is very difficult to adjust the color tone to be the same, and the change in the color of the product surface due to long-term use differs between the paint-applied part and the paint-uncoated part. The method of applying product waste on the ALC panel requires a product waste preparation process and a process of removing product waste after autoclaving, which is time consuming and may cause discoloration of the product waste itself. The properties of the surface will change over time.

  Patent Document 1 also proposes a method of forming a protective layer by attaching a stainless steel plate or the like to the air contact surface of a semi-cured body. According to this method, the surface property of the stainless steel plate is semi-cured. Will be transferred to the surface, and the surface properties will change.

  As a method for preventing the occurrence of discoloration of the calcium silicate molded body other than the above, for example, until the autoclave curing is performed after the semi-cured body curing is completed, the inside is partially replaced with, for example, nitrogen gas. A method of waiting the semi-cured body in a cured curing yard is conceivable.

JP-A-8-231284

  According to the said method, since contact with a semi-hardened body and air can be decreased, generation | occurrence | production of discoloration can be prevented rather than the manufacturing method of a general calcium silicate molded object. However, since the above method does not completely prevent the contact between the semi-cured product and air, it cannot be completely eliminated even if the discoloration can be reduced, and the facility for waiting the semi-cured product ( A high-sealing curing yard, etc.) is necessary and equipment costs are required.

  This invention was completed based on the above situations, Comprising: It aims at providing the manufacturing method of the calcium-silicate molded object which can fully prevent discoloration without spending an installation cost and effort. .

Regarding the mechanism of discoloration of the calcium silicate compact, details are still unknown and within the scope of estimation, but are considered as follows.
The raw material of the calcium silicate compact (silicic raw material / calcic raw material) contains metal-containing minerals such as iron-containing minerals. In the semi-cured state, the iron-containing mineral is considered to be a compound such as iron ion, iron hydroxide, iron oxide, or iron sulfide. When these iron-containing minerals are present near the surface of the semi-cured body, they are oxidized by the moisture contained in the semi-cured body and the moisture in the air, and various kinds of black-brown and red-brown iron oxides (FeO, Fe ₂ O ₃ ) and tan Various oxides such as oxyoxides (α, β, γ type) are formed. Here, the semi-cured product is alkaline, but when in contact with air, the calcium content (calcium hydroxide, etc.) reacts with carbon dioxide in the air to become calcium carbonate, and neutralization proceeds. The oxidation reaction of iron-containing minerals is difficult to react under alkaline conditions, and easily reacts under neutral conditions, so that the oxidation reaction is accelerated as the carbonization of the semi-cured product proceeds.

  That is, the oxidation of the metal-containing mineral, the carbonation of calcium hydroxide contained in the raw material, and the acceleration of the oxidation of the metal-containing mineral by this carbonation may contribute to the discoloration of the calcium silicate compact. Conceivable. Therefore, intensive study was conducted on countermeasures against these causes.

  As a result, it was found that the discoloration of the calcium silicate molded product can be sufficiently prevented by applying glycerin to the surface of the semi-cured product or mixing glycerin inside the semi-cured product. Even when diglycerin or polyglycerin having a polymerization degree of 3 or more was used, the same effect as when glycerin was used was obtained.

About the mechanism which suppresses discoloration of a calcium-silicate molded object by using glycerol, it thinks as follows.
Since glycerin has a lower oxygen solubility than water, the use of glycerin makes it difficult for oxygen to come into contact with the metal-containing mineral, thereby inhibiting oxidation.
In addition, since glycerin has a moisture absorption / moisturizing action, the use of glycerin suppresses moisture evaporation from the surface of the semi-cured body or molded body, and the formation of a glycerin film forms a metal mineral. And oxygen are difficult to contact.

Furthermore, since glycerin has a lower carbon dioxide solubility than water, the use of glycerin makes it difficult for carbon dioxide to react with the calcium content in the calcium silicate molded product, maintaining alkalinity and oxidizing the metal-containing mineral. Is suppressed.
In other words, glycerin acts directly and / or indirectly by suppressing the carbonation of calcium to prevent oxidation of metal-containing minerals contained in semi-cured bodies and molded bodies. It is thought that discoloration of the calcium silicate molded body may be prevented.

The present invention is based on such novel findings.
That is, the present invention is a calcium silicate molded body in which a semi-cured product obtained by semi-curing a raw material slurry obtained by adding water to a solid component mainly composed of a siliceous material and a calcareous material is semi-cured and cured. A method for producing a calcium silicate molded article, wherein one or more glycerins selected from glycerin, diglycerin, and polyglycerin having a polymerization degree of 3 or more are applied to the surface of the semi-cured product. It is.

  According to the present invention, the discoloration of the calcium silicate molded body can be sufficiently prevented only by applying glycerin to the surface of the semi-cured body, and no large-scale equipment is required and troublesome.

In the production method of the present invention (a production method including a step of applying glycerin to the surface of the semi-cured product), the following configuration is preferable.
The amount of glycerin applied is 20 g or more and 400 g or less per 1 m ² of the surface area of the semi-cured product. With such a configuration, the effect of suppressing discoloration can be enhanced. When the coating amount of glycerin is 30 g or more and 250 g or less per 1 m ² of the surface area of the semi-cured product, the discoloration suppressing effect can be further enhanced.

  Glycerin is spray-coated on the semi-cured product as an aqueous solution having a concentration of 10% by mass to 85% by mass. With such a configuration, since glycerin is adjusted to a viscosity suitable for spray coating, the coating operation can be simplified, and the coating amount of glycerin can be set to an appropriate amount. It is preferable that coating unevenness hardly occurs.

It is preferable that the calcium silicate compact is a lightweight cellular concrete. Lightweight cellular concrete (ALC) has the following properties: (1) When using ALC, a large number of panels are used side by side.
(2) Since ALC has more calcareous than other calcium silicate compacts, calcareous heat is generated and the temperature of the semi-cured product tends to be high, which facilitates the oxidation reaction and easily discolors.

  In other words, the ALC manufactured by the manufacturing method of the present invention exhibits the effect of preventing discoloration remarkably, so that the above configuration is preferable.

  In addition, the present invention provides a calcium silicate molded body for autoclaving a semi-cured product obtained by semi-curing a raw material slurry obtained by kneading and adding water to a solid component mainly composed of a siliceous material and a calcareous material. In the production method, calcium silicate molding, wherein the solid component, the water or the raw material slurry is mixed with one or more glycerins selected from glycerin, diglycerin, and polyglycerin having a polymerization degree of 3 or more. It is a manufacturing method of a body.

According to the present invention, the discoloration of the calcium silicate molded body can be sufficiently prevented only by mixing glycerin inside the semi-cured body, and no large-scale equipment is required and troublesome.
In the production method of the present invention (a production method including a step of mixing glycerin with a semi-cured product), the following configuration is preferable.

It is preferable that 0.5 to 7.0 liters of glycerin is mixed with respect to a volume of 1 m ³ of the raw material slurry before foam curing. If the amount of glycerin mixed is too large, foaming of the semi-cured product may be hindered, or the curing time of the raw material slurry (time to obtain a semi-cured product of a predetermined hardness) may be increased. If the amount is too small, the discoloration suppressing effect may be insufficient. The above configuration is preferable because the above problem does not occur and the effect of suppressing discoloration can be enhanced. In the above configuration, the glycerols, the volume 1 m ³ of feedstock slurry prior foaming and curing, when configured to mix 1.0 liters to 5.0 liters or less, it is possible to further enhance the color change suppressing effect, In addition, it is particularly preferable because the cost can be reduced.

It is preferable that the calcium silicate compact is a lightweight cellular concrete.
As described above, lightweight cellular concrete (ALC) has a property that the difference in color tone is conspicuous and is more easily discolored than other calcium silicate molded articles. preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the calcium-silicate molded object which can fully prevent discoloration can be provided, without spending installation cost and an effort.

The perspective view which shows the semi-hardened body used for preparation of the ALC panel for a standard color measurement The perspective view explaining the color measurement surface of the ALC panel for standard color measurement

Hereinafter, the manufacturing method of the calcium silicate molded object of this invention is demonstrated.
The present invention relates to a method for producing a calcium silicate molded body in which a semi-cured product obtained by semi-curing a raw material slurry obtained by adding water to a solid component mainly composed of a siliceous material and a calcareous material is semi-cured and cured. It is.

As a calcium silicate molded object obtained by the manufacturing method of the calcium silicate molded object of this invention, a lightweight cellular concrete (ALC), a silica ash brick, a calcium silicate board, a cement extrusion molding board, etc. are mentioned, for example. Among these, it is preferable to produce ALC by the production method of the present invention. This is because ALC has the following properties.
(1) When using ALC, since a large number of panels are used side by side, the difference in color tone between the panels is easily noticeable.
(2) Since ALC has more calcareous than other calcium silicate compacts, calcareous heat is generated and the temperature of the semi-cured product tends to be high, which facilitates the oxidation reaction and easily discolors.

  That is, the ALC manufactured by the manufacturing method of the present invention is preferable because the effect of preventing discoloration is remarkably exhibited.

  Now, the manufacturing method (1st method) of this invention has the characteristics in the place including the process of apply | coating glycerol on the surface of a semi-hardened body. In addition, the production method (second method) of the present invention is characterized in that it includes a step of mixing glycerol with a raw material slurry or the like. Each method will be described below.

(First method: production method including a step of applying glycerin to the surface of the semi-cured product)
In the first method of the present invention, first, water is added to a solid component mainly composed of a siliceous raw material and a calcareous raw material and kneaded to prepare a raw material slurry (raw material slurry preparation step).
As the siliceous raw material, one or a combination of two or more kinds of powders or granular materials known as raw materials containing SiO ₂ such as silica stone, silica sand, slag, fly ash and the like can be used.
As the calcareous raw material, powders or granular materials such as quick lime, slaked lime, ordinary Portland cement, early-strength Portland cement, and other various Portland cements can be used singly or in combination.

  Here, for example, when ALC is produced by the method of the present invention, a foaming agent such as aluminum powder, a water reducing agent, or the like can be used as the material of the raw material slurry, in addition to the solid component and water. In addition, when preparing the raw material slurry, in addition to the raw material as the main component, gypsum, reinforcing fiber, repeated raw material (when the semi-cured material obtained by foaming and hardening the raw material slurry is cut with a piano wire Or unnecessary ALC powder (unnecessary part generated when cutting ALC obtained by curing a semi-cured product) may be added. Addition of these raw materials is preferable because foaming of the raw material slurry is stabilized and raw material costs can be saved.

  The raw material slurry is obtained by adding 50 to 90 parts by mass of water to 100 parts by mass of the total solid components (silicic raw materials, raw materials such as calcareous raw materials and solid components such as gypsum). It is obtained by kneading.

  A semi-cured material is produced by placing the raw material slurry in a mold having a predetermined shape and curing it until it has a predetermined hardness (for example, hardness that can be cut with a piano wire) (semi-cured material production step).

  In the production method of the present invention, one or more glycerins selected from glycerin, diglycerin, and polyglycerin having a polymerization degree of 3 or more are applied to the surface of the semi-cured product obtained through the semi-cured product preparation step. (Glycerin application process). Among these glycerins, glycerin, diglycerin, and polyglycerin having a polymerization degree of 3 to 10 are preferable because they are easy to handle. The glycerin is preferably applied immediately after cutting the semi-cured product.

The coating amount of glycerin (stock solution) is preferably 20 g or more and 400 g or less per 1 m ^{2 of} the semi-cured body because the effect of preventing discoloration is high, and preferably 30 g or more and 250 g or less per 1 m ² of the semi-cured surface. This is particularly preferable because the effect of preventing discoloration is further enhanced. “Applied amount of glycerin (stock solution)” means a coated amount of glycerin as a stock solution.

If the coating amount of glycerin (stock solution) is less than 20 g per 1 m ² of the surface of the cured product, sufficient discoloration prevention effect may not be obtained. If the coating amount exceeds 400 g per 1 m ² of the semi-cured product, it is applied. Since the glycerins are excessive and liquid dripping occurs, the required surface properties cannot be obtained.

  As a method for applying glycerin, various methods such as spray coating, brush coating, a method of immersing a semi-cured product in glycerin, and various roll coater methods can be employed. Of these methods, brush coating and semi-cured dipping methods may change the surface shape, but spray coating takes advantage of the surface properties of the original calcium silicate compact and simplifies the coating process. In particular, this is a suitable method for producing ALC.

  Glycerin can be applied to the semi-cured product as it is, or diluted into water to form an aqueous solution. For example, in the case of spray coating, if the concentration of glycerin is an aqueous solution of 10% by mass or more and 85% by mass or less, the viscosity is adjusted to be suitable for spray coating, so that the coating operation can be simplified. And since the application quantity of (stock solution) of glycerol can be made into an appropriate quantity, it is hard to produce a coating nonuniformity and is preferable. If the concentration of glycerin is less than 10% by mass, the influence of water increases and the effect of suppressing discoloration decreases, and it is necessary to increase the coating amount in order to obtain a suitable discoloration suppressing effect. Is done. If the concentration of glycerin exceeds 85% by mass, the viscosity becomes unsuitable for spray coating, and in order to obtain a suitable discoloration suppressing effect, it is necessary to reduce the coating amount, resulting in uneven coating. There is.

  Next, when the semi-cured material that has undergone the glycerin coating step is cured at 180 ° C. to 190 ° C. for 4 hours to 24 hours, a calcium silicate compact is obtained.

(Second method: production method including a step of mixing glycerin into a raw material slurry or the like)
In the second method of the present invention, glycerin is mixed in a raw material slurry preparation step of preparing a raw material slurry by adding water to a solid component mainly composed of a siliceous raw material and a calcareous raw material and kneading them.
Glycerin is used by mixing with a solid component, water or raw material slurry. It is preferable to use glycerin mixed with water in that oxygen dissolved in water can be reduced.

  As the siliceous raw material, calcareous raw material, solid component, each material used for the raw material slurry, and glycerin, the same ones as in the first method can be used.

In the present invention, the amount of glycerin mixed is preferably 0.5 liters or more and 7.0 liters or less in the state of the stock solution with respect to the volume 1 m ³ of the raw material slurry before foam curing. When glycerin is mixed in the above range, the foaming property of the semi-cured product is not inhibited, the curing time is not prolonged, and the discoloration suppressing effect can be enhanced.
When the mixing amount of glycerin is less than 0.5 liter in the state of the stock solution with respect to 1 m ³ of the raw material slurry before foam curing, the discoloration suppressing effect may not be sufficient, and the mixing amount of glycerin is When the volume of the raw material slurry before foam curing is 1 m ³ , and it exceeds 7.0 liters in the state of the stock solution, the semi-cured product may not foam sufficiently.
Incidentally, the glycerols, the volume 1 m ³ of feedstock slurry prior foaming and curing, when configured to mix than 5.0 liters to 1.0 liters in the state of the stock solution, it is possible to further enhance the color change suppressing effect, In addition, it is particularly preferable because the cost can be reduced.

  Next, the raw material slurry obtained through the raw material slurry preparation step is placed in a mold having a predetermined shape, and is semi-cured until it reaches a predetermined hardness (for example, hardness that can be cut with a piano wire). A cured body is produced (semi-cured body production step). When the semi-cured product thus obtained is cured at 180 to 190 ° C. for 4 to 24 hours, a calcium silicate molded product is obtained.

<Example>
Hereinafter, the present invention will be described more specifically with reference to examples.
1. Examination of the discoloration prevention method of a calcium silicate molded object The evaluation test was done and examined about the various ALC panels produced by the method shown below.
(Production of ALC of Comparative Example 1)
(1) Production of semi-cured product 65 parts by mass of silica powder, 20 parts by mass of early cement, 11 parts by mass of quicklime powder, 4 parts by mass of gypsum, 70 parts by mass of water and aluminum powder with respect to 100 parts by mass of these solid components 0.06 parts by mass and 0.1 parts by mass of a water reducing agent were mixed to prepare a raw material slurry, which was placed in a mold, and foamed and cured. The semi-cured product after 3 hours was removed from the mold and cut into a predetermined size with a piano wire, and the non-product portion around the mold was removed to prepare a semi-cured product.

(2) Storage, Autoclave Curing The semi-cured product was stored for 2 hours in a curing yard maintained at 30 ° C. The semi-cured product was cured in an autoclave at 180 ° C. for 10 hours to produce an ALC panel of Comparative Example 1.

(3) Evaluation test (i) The ALC panel of Comparative Example 1 taken out from the autoclave was dried indoors until the moisture content measured using a moisture meter manufactured by Kett Science Laboratory was in the range of 10 to 20%. . The L value, a value, and b value at five locations on the surface of the ALC panel after drying were measured using a color difference meter [manufactured by Minolta Co., Ltd., CR-200], and each average value was calculated. . This value was taken as the L value, a value, and b value of the ALC panel of Comparative Example 1.

(Ii) The semi-cured body 1 produced by the same method as in the above (1) is longitudinally cut as shown in FIG. 1, and the longitudinal section 2 is arranged on the inner side so as to be in contact (that is, not in contact with air). Then, after storing in a curing yard kept at 30 ° C. for 2 hours, it was cured in an autoclave at 180 ° C. for 10 hours to produce the ALC panel 3 for standard color measurement shown in FIG.
During storage in the curing yard and during autoclave curing, the longitudinal section 2 arranged inside is the measurement surface 4 for measuring the standard color of the ALC panel 3 for standard color measurement. This measurement surface 4 The L value, a value, and b value were measured using a color difference meter [manufactured by Minolta Co., Ltd., CR-200], and the average value was calculated. This value was used as the L value, a value, and b value of the ALC panel that is a standard color.

  (Iii) The difference (ΔL, Δa, Δb) between the L value, a value, and b value in the ALC panel of Comparative Example 1 and the L value, a value, and b value of the ALC panel that is the standard color was calculated. . Next, ΔE was calculated by the following equation (1). Table 1 shows ΔL and ΔE.

  The L value is a value indicating brightness, the a value is a value indicating the degree of red-green, and the b value is a value indicating the degree of yellow-blue. If the difference in brightness is small and ΔE is small, it can be said that the color difference from the standard color is small.

(Production of ALC panel of Comparative Example 2 and storage in a closed curing yard)
An ALC panel of Comparative Example 2 was produced in the same manner as in Comparative Example 1 except that the semi-cured material produced in (1) of Comparative Example 1 was stored in a curing yard that was replaced with nitrogen and sealed. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

(Preparation of ALC panel of Comparative Example 3: Application of water)
Comparative Example 1 was the same as Comparative Example 1 except that water was applied to the surface of the semi-cured material prepared in (1) of Comparative Example 1 so as to be 30 g per 1 m ^{2 of} the semi-cured material, and then the product was kept in the curing yard. Thus, an ALC panel of Comparative Example 3 was produced. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

(Preparation of ALC panel of Comparative Example 4 using a stainless steel plate)
The ALC panel of Comparative Example 4 was produced in the same manner as Comparative Example 1 except that the surface of the semi-cured material produced in (1) of Comparative Example 1 was covered with a stainless steel plate and then waited in the curing yard. . An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

(Production of ALC panel of Comparative Example 5: Application of ALC product waste)
After applying the slurry of ALC product waste to the surface of the semi-cured material produced in (1) of Comparative Example 1 so that the coating amount per 1 m ² is 30 g, the product is put on standby in the curing yard. ALC panel of Comparative Example 5 was produced in the same manner as Comparative Example 1 except that. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

(Production of ALC panels of Comparative Examples 6 to 8: Application of various resins)
Instead of water, ALC panels of Comparative Examples 6 to 8 were prepared in the same manner as Comparative Example 3 except that the amount of resin shown below was applied. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.
Comparative Example 6: Apply 20% styrene acrylic resin [trade name (Nicazole), Nippon Carbide Industries, white resin] so that the amount of resin per 1 m ^{2 of} semi-cured product is 90 g.

Comparative Example 7: Acrylic ester resin A [trade name (CP wet coat), manufactured by Mizutani Paint Co., Ltd., white resin] having a concentration of 10% so that the amount of resin per 1 m ^{2 of} semi-cured product is 20 g. Coating

Comparative Example 8: Acrylic ester resin A having a concentration of 20% was applied so that the amount of resin per 1 m ^{2 of} semi-cured product was 40 g.

(Comparative Example 9 to Comparative Example 13 Production of ALC Panel: Application of Various Materials)
Instead of water, ALC panels of Comparative Examples 9 to 13 were prepared in the same manner as Comparative Example 3 except that the materials shown below were applied. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.
Comparative Example 8: An undiluted solution of an alkali silicate solution [trade name (RF-100), manufactured by Taiheiyo Materials Co., Ltd.] was applied so as to be 600 g per 1 m ^{2 of the} semi-cured product.

Comparative Example 9: Apply a stock solution of long chain alkyl-modified water repellent [trade name (KF-4917), manufactured by Shin-Etsu Silicone Co., Ltd.] so as to be 20 g per 1 m ^{2 of} semi-cured product.

Comparative Example 10: An aqueous solution of glycine having a concentration of 20% by mass (manufactured by Fuso Chemical Co., Ltd.) was applied so as to be 20 g per 1 m ^{2 of the} semi-cured product.

Comparative Example 11: An aqueous solution of glucose having a concentration of 30% by mass (manufactured by Sanei Saccharification Co., Ltd.) was applied so as to be 20 g per 1 m ^{2 of} semi-cured product

(Preparation of ALC panel of Example 1: Application of glycerin)
Immediately after removing the semi-cured product produced in (1) of Comparative Example 1 from the mold and removing the non-product portion around the mold, an aqueous glycerin solution having a concentration of 10% by mass on the surface is used. Was uniformly applied so that the coating amount as a glycerin stock solution was 30 g per 1 m ^{2 of the} semi-cured product, and then kept warm in the same manner as in (2) of Comparative Example 1 and cured by autoclave, so that the ALC of Example 1 A panel was produced. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

(Preparation of ALC panel of Example 2: Mixing of glycerin)
Solid components consisting of 65 parts by mass of silica powder, 20 parts by mass of early strength cement, 11 parts by mass of quicklime powder, and 4 parts by mass of gypsum were mixed. A mixture of 70 parts by mass of water with 100 parts by mass of the solid component and a glycerin stock solution corresponding to 0.50 liter per 1 m ³ of volume of the raw material slurry before foaming and curing, and 0.06 aluminum powder Mass parts and 1 part by mass of a water reducing agent were mixed in a solid component to prepare a raw material slurry. This raw material slurry was placed in a mold and foamed and cured. The semi-cured product after 3 hours was removed from the mold and cut into a predetermined size with a piano wire, and the non-product portion around the mold was removed to prepare a semi-cured product. This semi-cured product was stored in the same manner as in (2) of Comparative Example 1 and autoclaved to produce an ALC panel of Example 2. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 1.

For Comparative Examples 1 to 11 and Examples 1 and 2, the degree of the discoloration preventing effect was determined according to the following criteria, and the results are shown in Table 1 together with ΔE and ΔL.
Evaluation criteria based on ΔE and ΔL are as follows: ×: ΔE is larger than 3.0 (a color difference from the standard color is noticeable)
Δ: ΔE is greater than 1.5 and less than or equal to 3.0 (a slight color difference from the standard color is recognized)
○: ΔE is 1.5 or less (a color difference from the standard color is hardly recognized)
None of the Example products had manufacturing problems, but some of the Comparative Example products (Comparative Examples 1 to 11) had manufacturing problems, so these were manufactured at the time of evaluation. The evaluation was made in consideration of the above problems, and the reasons are shown in Table 1 as comments.

(Results and discussion)
It was found that the ALC panel of Example 1 and the ALC panel of Example 2 produced by the production method of the present invention showed almost no color difference from the standard color and had a high anti-discoloration effect. In addition, in addition to glycerin, when the ALC panel is produced by the same method as in Example 1 and Example 2 using diglycerin or polyglycerin having a polymerization degree of 3 or more, the same effect as when glycerin is used is obtained. there were.

On the other hand, it was found that the ALC panels of comparative products (Comparative Examples 1 to 11) were inferior in discoloration prevention effect than the ALC panels manufactured by the method of the present invention.
Among the comparative examples, the ALC panel of Comparative Example 2 stored in the curing yard in which the semi-cured body was sealed, the ALC panel of Comparative Example 3 in which the semi-cured body was coated with a stainless steel plate, and stored on the surface of the semi-cured body. In the ALC panel of Comparative Example 4 to which product waste was applied, a slight discoloration preventing effect was observed.
However, Comparative Example 2 requires special equipment, and Comparative Example 3 and Comparative Example 4 are troublesome and complicated, and also have the disadvantage that the surface properties of the original ALC panel cannot be obtained ( Production problems).

2. Examination of application amount and concentration of glycerin In order to examine the application amount of glycerin (application amount as glycerin stock solution) and its concentration, various concentrations of glycerin were applied to the semi-cured material by changing the application amount to produce an ALC panel. Then, an evaluation test was conducted.
(Preparation of ALC panels of Examples 3-39)
In the same manner as in Example 1, except that the concentration (mass%) of glycerin used and the coating amount per 1 m ^{2 of} the semi-cured product were changed to the amounts (g / m ² ) shown in Table 2, Example 3 39 ALC panels were prepared respectively. An evaluation test was performed in the same manner as in Comparative Example 1, and ΔL and ΔE were calculated and shown in Table 2. In Table 2, the results of Example 1 and the evaluation results are also shown at the corresponding locations. The “application amount” in Table 2 means the application amount as a glycerol stock solution.
The evaluation criteria are as follows.
X: ΔE is larger than 3.0 (a color difference from the standard color is noticeable)
Δ: ΔE is greater than 1.5 and less than or equal to 3.0 (a slight color difference from the standard color is recognized)
○: ΔE is 1.5 or less (a color difference from the standard color is hardly recognized)
A: ΔE is 1.5 or less and ΔL is −1 or more and 1 or less (a color difference from the standard color is hardly recognized and there is almost no difference in brightness from the standard color).

(Results and discussion)
In the ALC panels of Example 1 and Examples 3 to 39, ΔE was 1.83 or less, and it was found that the effect of preventing discoloration was higher than that of the comparative products (Comparative Examples 1 to 11).
Among these, the concentration of glycerin is 10% by mass or more, and the coating amount of glycerol (stock solution) is 20 g / m ² or more and 400 g / m ² or less (Example 1, Examples 6 to 22, Examples) In 24-31 and Examples 33-38), good results with ΔE of 1.48 or less were obtained. From this result, it was found that the concentration of glycerin is preferably 10% by mass or more and the coating amount of glycerol (stock solution) is preferably 20 g / m ² or more and 400 g / m ² or less.

In particular, the concentration of glycerin is 10% by mass or more and the glycerin (stock solution) coating amount is 30 g / m ² or more and 250 g / m ² or less (Example 1, Examples 7 to 10, Examples 12 to 21 and Examples 25-28, Examples 30-31, and Examples 34-37) gave good results that ΔL was in the range of −1 to 1 and ΔE was 1.32 or less. . From this result, it was found that the coating amount of glycerol (stock solution) is particularly preferably 30 g / m ² or more and 250 g / m ² or less.

3. Examination of mixing amount of glycerin In order to examine the mixing amount of glycerin, ALC panels were prepared using semi-cured bodies containing various amounts of glycerin, and an evaluation test was performed.
(Production of ALC panels of Examples 40 to 49)
ALC panels of Examples 40 to 48 were prepared and evaluated, and ΔL and ΔE were calculated in the same manner as in Example 2 except that the amount of the glycerin stock solution was changed to the amount shown in Table 3 (liter / m ³ ). Table 3 shows the results. In Table 3, the result of the evaluation test of Example 2 is also described in the corresponding part.
For Example 49, an ALC panel was prepared in the same manner as in Example 2 except that the mixing amount of the glycerol stock solution was changed to the amount shown in Table 3 (liter / m ³ ). The provided raw material slurry did not cure to such an extent that it could be removed from the mold after 3 hours. Therefore, the ALC panel of Example 49 was prepared by placing the raw slurry prepared in the same manner as in Example 2 with the amount of glycerin stock solution mixed in the amount shown in Table 3 (liter / m ³ ) in a mold, After 10 hours, the semi-cured product is removed from the mold, cut into a predetermined size with a piano wire, and the semi-cured product from which non-product parts around the mold are removed is stored in the same manner as (2) of Comparative Example 1. It was prepared by curing the autoclave. The evaluation test was performed on the ALC panel of Example 49 manufactured in the above procedure as in the other examples, and ΔL and ΔE were calculated and shown in Table 3.
Example 2 and Examples 40 to 49 were evaluated in consideration of not only the numerical values of ΔL and ΔE but also the manufacturing cost, etc., and are shown in Table 3.

(Results and discussion)
The ALC panels (Example products) of Example 2 and Examples 40 to 49 have ΔE of 1.87 or less, and are more effective in preventing discoloration than the comparative products (Comparative Examples 1 to 11). I understood.
Among the products of this example, ΔE was evaluated as Δ for Example 40 because ΔE was greater than 1.5 and 3.0 or less (a slight color difference from the standard color was observed).
Among the products of this example, in the case where the amount of glycerin mixed is 0.50 liter / m ³ or more (Example 2, Examples 41 to 49), ΔE is 1.5 or less, and the color of the standard color Good results were obtained with little difference. Although the ALC panel of Example 49 is excellent in the effect of preventing discoloration, as described above, it takes a longer time to produce a semi-cured body (curing time) than the products of the other examples, so that it can be used for actual production. Was unsatisfactory and was evaluated as Δ.
From this result, in the present invention, it is preferable that the mixing amount of glycerin per 1 m ³ volume of the raw slurry before foaming / curing is 0.50 to 7.0 liter / m ^{3 in} the state of the stock solution. all right.

Among the above preferred examples (Examples 2 and 41 to 48), ΔE is 1 or less particularly when the amount of glycerin mixed is 1.00 liter / m ³ or more (Examples 43 to 48). And good results were obtained in that ΔL was in the range of −1 to 1.
When the amount of glycerin mixed was less than 5.20 liters / m ³ (Examples 43 to 45), the effect of preventing discoloration was significantly improved as the amount of glycerin mixed was increased. However, when the mixing amount of glycerin is 5.20 liter / m ³ or more (Examples 46 to 48), the discoloration preventing effect is not improved due to the increase in the mixing amount of glycerin, or the discoloring preventing effect is improved. Even if it is small, it was evaluated as “good” in consideration of cost although it was excellent in the discoloration prevention effect.
From this result, in the present invention, it is particularly preferable that the mixing amount of glycerin per 1 m ³ volume of the raw material slurry before foaming / curing is 1.00 to 5.0 liters / m ^{3 in} the state of the stock solution. I understood.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, early strong cement and quicklime are used as the calcareous raw material, but ordinary Portland cement or the like may be used.
(2) In the above embodiment, the method for producing ALC has been shown. However, the present invention may be applied to a method for producing a calcium silicate compact such as silicate brick.

DESCRIPTION OF SYMBOLS 1 ... Semi-cured body 2 ... Longitudinal section 3 ... ALC panel for standard color measurement 4 ... Measurement surface

Claims (9)

In a method for producing a calcium silicate molded body in which a semi-cured product obtained by semi-curing a raw material slurry obtained by kneading water by adding water to a solid component mainly composed of a siliceous material and a calcareous material is cured in an autoclave.
One or more glycerol selected from glycerol, diglycerol, and polyglycerol with a polymerization degree of 3 or more is apply | coated to the surface of the said semi-hardened body, The manufacturing method of the calcium-silicate molded object characterized by the above-mentioned. The method for producing a calcium silicate molded body according to claim 1, wherein the coating amount of the glycerin is 20 g or more and 400 g or less per 1 m ² of the surface of the semi-cured body. The method for producing a calcium silicate molded body according to claim 1, wherein the coating amount of the glycerin is 30 g or more and 250 g or less per 1 m ² of the surface of the semi-cured body. The calcium silicate molded body according to any one of claims 1 to 3, wherein the glycerin is spray-coated on the semi-cured body as an aqueous solution having a concentration of 10 mass% or more and 85 mass% or less. Manufacturing method. The method for producing a calcium silicate molded body according to any one of claims 1 to 4, wherein the calcium silicate molded body is lightweight cellular concrete. In a method for producing a calcium silicate molded body in which a semi-cured product obtained by semi-curing a raw material slurry obtained by kneading water by adding water to a solid component mainly composed of a siliceous material and a calcareous material is cured in an autoclave.
One or more types of glycerol selected from glycerol, diglycerol, and polyglycerol with a polymerization degree of 3 or more are mixed with the said solid component, the said water, or the said raw material slurry, The manufacturing method of the calcium-silicate molded object characterized by the above-mentioned. The method for producing a calcium silicate molded body according to claim 6, wherein the glycerin is mixed in an amount of 0.5 liter to 7.0 liter with respect to a volume of 1 m ³ of the raw material slurry before foam curing. The method for producing a calcium silicate molded body according to claim 6, wherein the glycerin is mixed in an amount of 1.0 liter to 5.0 liter with respect to a volume of 1 m ³ of the raw material slurry before foam curing. The method for producing a calcium silicate molded body according to any one of claims 6 to 8, wherein the calcium silicate molded body is lightweight cellular concrete.

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