JP2511681B2 - High strength and lightweight calcium silicate compact and method for producing the same - Google Patents

Description

The present invention relates to a high-strength lightweight calcium silicate compact and a method for producing the same.

More specifically, a calcium silicate compact that is lightweight and has high strength, has the same processability as natural wood, and at the same time has excellent fire resistance, decay resistance and dimensional stability, and can be suitably used as a building material, and The present invention relates to a manufacturing method thereof.

[Prior Art] Calcium silicate is a lightweight and thermally stable substance,
A molded product utilizing this characteristic is commercially available. Of these, heat insulating materials and heat insulating materials are used to make good use of the characteristic of being lightweight, and silica calboard is used to make use of the characteristics of being thermally stable and fire resistant, and they are produced in large quantities. However, the former has a bulk density of 0.3 g / cm ³ or less,
The latter has a bulk density of 0.7 g / cm ³ or more. Molded bodies corresponding to an intermediate bulk density of 0.3 to 0.7 g / cm ³ have hardly been commercialized in the past.

The value of the bulk density of 0.3 to 0.7 g / cm ³ is almost the same as that of natural wood, and an attempt to manufacture artificial wood by molding calcium silicate has been proposed. For example, (1)
100 parts by weight of calcium silicate hydrate, 5 to 30 parts by weight of styrene-butadiene copolymer latex containing a carboxyl group (as solid content), an aqueous slurry comprising a cationic polymer flocculant and water is molded and dried. Formed calcium silicate compact (JP-A-60-246251), (2) 100 parts by weight of solid content of calcium silicate hydrate slurry, hydrophobic ethylenically unsaturated monomer in the absence of an emulsifier A calcium silicate-based molded product obtained by molding and drying a composition comprising 5 to 50 parts by weight (as a solid content) of a polymer emulsion obtained by the polymerization of (1) and 0.05 to 15 parts by weight of a coagulant (JP-A-61
-17462).

[Problems to be Solved by the Invention] However, according to the examples of the specification, the molded product of the invention (1) has a bending strength of 40 to 110 kgf / cm ^{2 at a} bulk density of 0.5 g / cm ^3.
It's just Further, styrene-butadiene copolymer latex is dissolved in toluene and xylene used as a solvent for paint, so when coating the surface of the molded product,
There is a drawback that the type and amount of paint are limited, and it is not possible to impart sufficient decorativeness to the molded product.

Further, the molded product of the invention of (2) is intended to solve the problem of strength, and according to the examples, the bulk specific gravity is 0.44 to
The bending strength is 0.48 gcm ³ and the bending strength is 130 to 150 kgf / cm ² , but since 30 parts (solid content) of the polymer emulsion is added, there is a problem in terms of fire resistance.

The present invention is to improve such drawbacks of the conventional invention, and to provide a calcium silicate compact excellent in bending strength, fire resistance and solvent resistance.

[Means for Solving Problems] The present invention relates to 100 parts by weight of calcium silicate hydrate, 3 to 20 parts by weight of self-crosslinking acrylic acid ester polymer, 1 to 30 parts by weight of reinforcing fiber and an anionic dispersant. The present invention relates to a high-strength lightweight calcium silicate compact comprising 0.1 to 3 parts by weight and a method for producing the same.

The calcium silicate compact of the present invention is a mixture of a calcium silicate slurry, a self-crosslinking acrylic acid ester polymer emulsion, a reinforcing fiber and an anionic dispersant, and an expansive material if necessary.
Adjust the weight ratio of solids to 4 to 12, then mix,
It can be produced by drying after dehydration press molding. A self-crosslinking acrylic ester polymer emulsion was added, and the water / solid content weight ratio was 4 in the presence of an anionic dispersant.
By using the slurry of No. 12 to 12, it is possible to provide a calcium silicate compact having high strength and excellent solvent resistance as compared with the conventional calcium silicate compact.

The calcium silicate of the present invention is usually tobermorite obtained by a hydrothermal synthesis reaction from a calcareous raw material, a siliceous raw material, and water, and calcium silicate called zonotolite is suitable, and in the production of a calcium silicate compact, siliceous Calcium acid slurry Specifically, it is used as a calcium silicate hydrate aqueous slurry. Calcareous raw materials include quick lime and slaked lime, and siliceous raw materials include silica stone, silica sand, and ferrosilicon dust, which are used as finely pulverized products. A calcareous raw material, a siliceous raw material, and water are mixed in a predetermined ratio, and a hydrothermal synthesis reaction is usually performed by an autoclave to obtain a calcium silicate hydrate aqueous slurry (hereinafter, may be simply referred to as calcium silicate slurry). To manufacture. The mixing ratio of the calcareous raw material and the siliceous raw material varies depending on the type of calcium silicate to be synthesized, the source of the raw material used, and the like. For example, when zonotolite (6CaO ・ 6SiO ₂・ H ₂ O) is synthesized, CaO / SiO ₂
The calcareous raw material and the siliceous raw material are blended so that the molar ratio becomes approximately 1. The mixing ratio of these raw materials and water is 5 to 15 by weight ratio of water / (calcium raw material + siliceous raw material). A calcareous raw material, a siliceous raw material and water, which are mixed in a predetermined ratio, are charged into an autoclave, and a hydrothermal synthesis reaction is performed while stirring at a temperature of 150 to 250 ° C for 1 to 24 hours to produce a calcium silicate slurry.

Next, a calcium silicate slurry, a self-crosslinking acrylic ester polymer emulsion, reinforcing fibers, an anionic dispersant and the like are mixed.

The crosslinkable functional group of the self-crosslinking acrylic acid ester polymer is not particularly limited, but can be introduced by copolymerizing a monomer having a carboxyl group, a hydroxyl group, an epoxy group, an amino group, a methylol group or the like.

The film forming temperature has a correlation with the hardness of the film, and good results can be obtained at 10 to 40 ° C, preferably 10 to 30 ° C. When an acrylic acid ester polymer with a film-forming temperature lower than 10 ° C is added, the bending strength of the molded product becomes low and the film-forming temperature is 40 ° C.
If it is higher, the bending strength is lowered and the flexibility is further deteriorated, so that an elastic body such as wood cannot be manufactured. Acrylic ester polymer is calcium silicate 100
3 to 20 parts by weight is used with respect to parts by weight. If the amount used is too small, the workability will be poor, and the strength will be weak, and if it is too large, there will be problems with the fire resistance.

When a non-crosslinked acrylic acid ester polymer emulsion is used, there is no problem in the bending strength and workability of the molded product, but the solvent resistance is poor.

As a reinforcing fiber, so-called yarn type E glass which has been converged with starch or PVA can be usually used. Glass fiber improves the strength and elastic modulus of the molded product, improves the retention of calcium silicate and acrylic acid ester polymer emulsion in the slurry during manufacturing, and improves the filtration separation during pressure dehydration molding. However, there are processability, water resistance,
From the viewpoint of heat resistance and the like, the amount used is 1 to 30 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of calcium silicate.

The anionic dispersant is not particularly limited, but is lignin-based, higher polyhydric alcohol sulfonate-based, oxyorganic acid-based, alkylarisulfonate and highly condensate-based, melamine condensate-based, β-naphthalenesulfonic acid. Usual cement dispersants such as formalin condensates can be used.
The amount used is 0.1 to 3 parts by weight.

By adding the anionic dispersant, the optimum slurry viscosity can be obtained even if the water / solid content weight ratio is lowered. As described above, by lowering the water / solid content weight ratio of the slurry, the fixing of the acrylic ester polymer to calcium silicate is improved. In addition, the blended glass fibers do not aggregate into pills and are uniformly dispersed in the slurry.
Further, since the anionic dispersant improves the wettability between the glass fiber and the slurry, it enhances the adhesiveness of the glass fiber to the calcium silicate or acrylate polymer and improves the bending strength of the product.

Calcium silicate slurry, emulsion and slurry in which each substance such as glass fiber is uniformly dispersed are molded by, for example, a method of filling in a mold and filtering and dehydrating under pressure, but other molding methods are appropriately used depending on the purpose and application. Can be adopted. After molding and drying, the desired calcium silicate compact is obtained. The drying temperature is usually 60 ° C to 160 ° C, preferably 80 ° C to 140 ° C.

[Examples] Examples of the present invention are shown below, but the present invention is not limited to the examples. The physical properties of the calcium silicate compact were tested by the following methods.

(1) Bending strength: According to JIS A1408.

(2) Workability: Judgment was made by comparison with wood when wood processing operations such as planing, nailing and sawing were performed.

(3) Solvent resistance: Moisture-curing urethane-based sealer was applied to 200 g per 1 m ² of the molded body, and judged by the presence or absence of peeling on the side surface.

Example 1 Silica stone powder and slaked lime were mixed so that the molar ratio of SiO ₂ / CaO was 1 and 12 times amount of water was added to the total weight of CaO and SiO ₂ while stirring in an autoclave. Temperature 210 ℃,
The hydrothermal synthesis reaction was performed at a pressure of 19 kgf / cm ² for 3 hours. The calcium silicate slurry thus obtained is dehydrated so that the weight ratio of water / solid content is 9. The acrylic ester polymer emulsion A shown in Table 1 was added to this slurry in an amount of 5 parts by weight in solid content, 7 parts by weight of water-dispersible glass fiber, and 100 parts by weight of solid content of calcium silicate slurry. Anionic dispersant that is a sodium salt 0.5
Parts by weight were added and mixed.

The obtained calcium silicate hydrate aqueous slurry was filled in a mold, pressure-filtered and dehydrated, and then dried at 120 ° C. for 16 hours to obtain a calcium silicate compact.

 The test results of the molded product are shown in Table 2.

Examples 2, 3, 4 The amount of acrylic acid ester polymer emulsion added was
A molded product was obtained in the same manner as in Example 1 except that the solid content of the calcium silicate slurry was changed to 3, 10 and 20 parts by weight with respect to 100 parts by weight of the solid content. Table 2 shows the results.

Comparative Example 1 A molded product was obtained in the same manner as in Example 1 except that the acrylic acid ester polymer emulsion was not added. The test results are shown in Table 3.

Comparative Example 2 Pressure filtration dehydration was performed in the same manner as in Example 1 except that glass fiber was not added, but cracks occurred during drying, and a molded body was not obtained.

Example 5 A molded product was obtained in the same manner as in Example 1 except that the acrylic acid ester polymer emulsion B shown in Table 1 was used instead of the acrylic acid ester polymer emulsion A used in Example 1. Table 4 shows the results.

Comparative Examples 3, 4, 5 Same as Example 1 except that the acrylic acid ester polymer emulsions C, D and E shown in Table 1 were used instead of the acrylic acid ester polymer emulsion A used in Example 1. A molded body was obtained. Table 4 shows the results.

Comparative Example 6 Instead of the acrylic ester polymer emulsion,
A molded product was obtained in the same manner as in Example 1 except that the carboxyl-modified styrene-butadiene copolymer emulsion was used. Table 4 shows the results.

[Advantages of the Invention] The present invention provides a calcium silicate compact which is lightweight and has high strength, is excellent in fire resistance and solvent resistance, and has the same processability as wood as a building material, and a method for producing the same. provide.

Claims (2)

(57) [Claims] 1. A calcium silicate hydrate 100 parts by weight, a self-crosslinking acrylic ester polymer having a film forming temperature of 10 to 40 ° C. 3 to 20 parts by weight, reinforcing fibers 1 to 30 parts by weight, and an anionic dispersion. A high-strength, lightweight calcium silicate compact comprising 0.1 to 3 parts by weight of the agent. 2. A slurry of 100 parts by weight of calcium silicate hydrate, 3 to 20 parts by weight of a self-crosslinking acrylic ester polymer having a film forming temperature of 10 to 40 ° C., 1 to 30 parts by weight of reinforcing fibers, and anions. High-strength, lightweight silicic acid characterized by mixing 0.1 to 3 parts by weight of a dispersant and adjusting the amount of water so that the weight ratio of water / solid content is 4 to 12, mixing, dehydrating press-molding, and then drying. A method for producing a calcium compact.