Molded body formed from curable composition

Abstract

To provide a molded body which has high strength, high ductility, and excellent dimensional stability while maintaining incombustibility and fire resistance. A molded body formed from a curable composition containing (A) at least one aluminosilicate source, (B) an alkali metal hydroxide, (C) a calcium ion source, and (D) an alkali resistant fiber, wherein the aluminosilicate source (A) has an SiO.sub.2 content of 50% by mass or more based on a total mass of the aluminosilicate source (A), an amorphous ratio of 50% by mass or higher, and an average particle diameter of 50 μm or smaller, and comprises an aluminosilicate source having an average particle diameter of 10 μm or smaller in an amount of 30% by mass or more based on the total mass of the aluminosilicate source (A).

Claims

1. A molded body formed from a curable composition comprising (A) at least one aluminosilicate source, (B) an alkali metal hydroxide, (C) a calcium ion source, and (D) an alkali resistant fiber, wherein the aluminosilicate source (A) has an SiO.sub.2 content of 50% by mass or more based on a total mass of the aluminosilicate source (A), an amorphous ratio of 50% by mass or higher, and an average particle diameter of 50 μm or smaller, and comprises an aluminosilicate source having an average particle diameter of 10 μm or smaller in an amount of 30% by mass or more based on the total mass of the aluminosilicate source (A), and wherein the curable composition comprises 10 to 140 parts by mass of the calcium ion source (C) based on 100 parts by mass of the aluminosilicate source (A).

2. The molded body according to claim 1, comprising at least a volcanic ash-derived substance as the aluminosilicate source (A).

3. The molded body according to claim 1, wherein the curable composition comprises 10 to 100 parts by mass of the alkali metal hydroxide (B) based on 100 parts by mass of the aluminosilicate source (A).

4. The molded body according to claim 1, wherein a content of the alkali resistant fiber (D) is 0.1 to 5 parts by mass based on 100 parts by mass of the molded body.

5. The molded body according to claim 1, wherein the alkali resistant fiber (D) has an average fiber diameter of 100 μm or smaller, and an aspect ratio of 50 to 2,000.

6. The molded body according to claim 1, wherein a variation coefficient of an average content of the alkali resistant fiber (D) contained in 10 cut pieces with a weight of 20 g cut out from a whole or a part of the molded body is 30% or lower.

7. The molded body according to claim 1, wherein the alkali resistant fiber (D) is at least one selected from the group consisting of a polyvinyl alcohol-based fiber, a polyethylene fiber, a polypropylene fiber, an acrylic fiber, and an aramid fiber.

8. A method for producing the molded body according to claim 1, comprising mixing a component comprising at least one aluminosilicate source (A), an alkali metal hydroxide (B), and a calcium ion source (C), with water, preparing a curable composition by adding an alkali resistant fiber (D) to the obtained mixture and further mixing the mixture, and obtaining the molded body by molding the obtained curable composition and then curing the curable composition.

9. The method according to claim 8, wherein the aluminosilicate source (A) comprises at least a volcanic ash-derived substance.

10. A method for producing a molded body, comprising mixing at least one aluminosilicate source (A) and an alkali metal hydroxide (B), with water, forming a precursor by heating the obtained mixture to 50 to 180° C. to react the mixture, and then cooling the mixture to 50° C. or lower, preparing a curable composition by adding a component comprising a calcium ion source (C) and an alkali resistant fiber (D) to the obtained precursor and further mixing the mixture, and obtaining the molded body by molding the obtained curable composition and then curing the curable composition.

11. A molded body formed from a curable composition comprising (A) at least one aluminosilicate source, (B) an alkali metal hydroxide, (C) a calcium ion source, and (D) an alkali resistant fiber, wherein the aluminosilicate source (A) has an SiO.sub.2 content of 50% by mass or more based on a total mass of the aluminosilicate source (A), an amorphous ratio of 50% by mass or higher, and an average particle diameter of 50 μm or smaller, and comprises an aluminosilicate source having an average particle diameter of 10 μm or smaller in an amount of 30% by mass or more based on the total mass of the aluminosilicate source (A), and wherein the molded body formed from a curable composition comprises at least a volcanic ash-derived substance as the aluminosilicate source (A).

Description

EXAMPLES

(1) Hereinafter, the present invention will be more specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to these examples.

(2) <Measurement Method and Evaluation Method>

(3) Various measurement methods and evaluation methods in Examples and Comparative Examples are as follows.

(4) [SiO.sub.2 Content and Amorphous Ratio in Aluminosilicate Source]

(5) An SiO.sub.2 content was determined by quantifying an Si content by a fluorescent X-ray measuring apparatus (RIX3100, produced by Rigaku Co.) and converting the Si content in terms of oxides.

(6) In addition, an amorphous ratio was calculated in accordance with the following method.

(7) (i) An abundance ratio of whole crystals contained in the aluminosilicate source was quantified by Rietveld analysis using an X-ray diffractometer (SmartLab, produced by Rigaku Co.).

(8) (ii) The aluminosilicate source was charged into a muffle furnace (P0310, produced by Yamato Scientific Co., Ltd.) set at 1000° C., and an ignition loss was determined from a change in the mass between before and after the charging.

(9) (iii) An amorphous ratio was calculated in accordance with the following mathematical formula.
Amorphous ratio (% by mass)=100−ignition loss (% by mass)−sum of crystal abundance ratio (% by mass)  [Mathematical formula 1]
[Average Particle Diameter of Aluminosilicate Source, and Proportion of Aluminosilicate Source Having Average Particle Diameter of 10 μm or Smaller]

(10) An average particle diameter of the aluminosilicate source, and a proportion of the aluminosilicate source having an average particle diameter of 10 μm or smaller were determined from a particle size distribution obtained using a dynamic light-scattering photometer DLS-7000 produced by Otsuka Electronics Co., Ltd.

(11) [Average Fiber Diameter and Aspect Ratio of Alkali Resistant Fiber (D)]

(12) Regarding an average fiber diameter, 20 fibers were randomly taken out, a fiber diameter in the middle of the length direction of each fiber was measured with an optical microscope, and the average value was defined as the average fiber diameter. An average fiber length was calculated in accordance with JIS L 1015 “Test Methods for Man-Made Staple Fibres (8.5.1)”, and an aspect ratio of the fiber was determined from a ratio between the average fiber length and the average fiber diameter.

(13) [Content of Alkali Resistant Fiber (D), and Variation Coefficient of Average Content of Alkali Resistant Fiber (D)]

(14) Pieces with a weight of 20 g were cut out from the molded body, 11 pieces were randomly selected among the cut pieces, dried at 105° C. for 3 hours, and then a weight of each cut piece [W.sub.1 to W.sub.11 (g)] was measured.

(15) Among the 11 cut pieces, one was pulverized in a mortar. Herein, a case of pulverizing a cut piece having a weight of W.sub.11 (g) will be explained. After the pulverizing, water was added to the pulverized material, which was filtered through a 10-mesh wire net to separate the alkali resistant fiber (D) and a matrix. Subsequently, a matrix was collected by further filtering the filtrate through a filter paper, the matrix was dried at 105° C. for 3 hours, and then a weight W.sub.11-1 (g) of the matrix was precisely measured. Subsequently, the matrix was charged in the muffle furnace at 600° C. for 30 minutes, then cooled, and then the weight W.sub.11-2 (g) of the matrix was measured to calculate a weight loss ratio X (%) of the matrix in accordance with the following mathematical formula.
Weight loss ratio X (%) of matrix={(W.sub.11-1−W.sub.11-2)/W.sub.11-1}×100  [Mathematical formula 2]

(16) Subsequently, the remaining 10 cut pieces [cut pieces having weights of W.sub.1 to W.sub.10 (g)] were charged in the muffle furnace at 600° C. for 30 minutes to burn the alkali resistant fiber (D) contained in the cut pieces, then cooled, and then each weight [W.sub.1-1 to W.sub.10-1 (g)] was measured.

(17) A content of the alkali resistant fiber (D) in the cut piece having a weight of W.sub.1 (g) was calculated in accordance with the following mathematical formula.
Content (%) of alkali resistant fiber(D) in cut piece having weight of W.sub.1=[{W.sub.1×(100−X)/100−W.sub.1-1}/W.sub.1]×100  [Mathematical formula 3]

(18) Also for each of the cut pieces having weights of W.sub.2 to W.sub.10 (g), the content of the alkali resistant fiber (D) was calculated.

(19) Furthermore, a standard deviation and an average value of the content of the alkali resistant fiber (D) in the cut pieces having weights of W.sub.1 to W.sub.10 (g) were calculated to calculate a variation coefficient of the average content of the alkali resistant fiber (D) in accordance with the following mathematical formula.
Variation coefficient (%) of content of alkali resistant fiber (D)={standard deviation of content (%) of alkali resistant fiber (D)/average content (%) of alkali resistant fiber (D), in each cut piece}=100  [Mathematical formula 4]

(20) In addition, from the content of the alkali resistant fiber (D) in each of the cut pieces having weights of W.sub.1 to W.sub.10 (g) determined in accordance with the above method, a proportion of the alkali resistant fiber (D) based on 100 parts by mass of each cut piece was calculated. An average of the proportions was calculated, and defined as the proportion of the alkali resistant fiber (D) based on 100 parts by mass of the molded body.

(21) [Bending Strength and Bending Toughness, and Variation Coefficient of Bending Strength of Molded Body]

(22) Bending strength and bending toughness of the molded body were determined by performing a bending test with n=6 in a third-point loading manner in accordance with JIS A 1106: 2006. In addition, a variation coefficient of the bending strength was calculated in accordance with the following mathematical formula.
Variation coefficient (%) of the bending strength=[standard deviation of bending strength (N/mm.sup.2)/average value of bending strength (N/mm.sup.2), in each test molded body]×100  [Mathematical formula 5]

(23) [Dimensional Change Rate of Molded Body]

(24) According to JIS A 5430, the molded body was put into a dryer with a stirrer, the temperature of the dryer was maintained at 60±3° C., and after 24 hours, the molded body was taken out, put into a desiccator humidity-controlled with silica gel, and left until the temperature reached 20±1.5° C. Subsequently, a milk-colored glass was attached to the molded body, and gauge lines were marked such that a distance between the gauge lines was about 140 μm, a length between the gauge lines was measured using a comparator with an accuracy of 1/500 μm, and this length was defined as the length between the gauge lines in a dry state. Subsequently, the molded body was erected such that the length direction of the molded body was horizontal, and immersed in water at 20° C.±1.5° C. such that the upper surface of the molded body is about 30 μm below the water surface. After 24 hours, the molded body was taken out of water, water adhering to the surface was wiped off, the length between the gauge lines was measured again, and this length was defined as the length between the gauge lines in a water absorption state. Then, a dimensional change rate of the molded body due to the water absorption was calculated in accordance with the following mathematical formula.
Dimensional change rate (%)=[{length between gauge lines in water absorption state (mm) −length between gauge lines in dry state (mm)}/length between gauge lines in dry state (mm)]×100  [Mathematical formula 6]

Example 1

(25) Using the materials shown in Table 1 and Table 2 mentioned below, curable compositions were prepared in amounts shown in Table 2, and molded bodies were produced from the obtained curable compositions.

(26) Specifically, first, an alkali metal compound in an amount shown in Table 2 was dissolved in water to prepare an aqueous solution of the alkali metal compound. Next, an aluminosilicate source, a calcium ion source and sand in amounts shown in Table 2 were put into a mortar mixer and mixed for 1 minute, then the aqueous solution was put into the mortar mixer, and mixed for 3 minutes. Subsequently, fibers aligned and converged in one direction in an amount shown in Table 2 were put into a mortar mixer and mixed for another 1 minute to prepare a curable composition. The obtained curable composition was poured and filled into a mold of 6 cm in width×25 cm in length×1 cm in thickness, cured under normal pressure at 80° C.×RH90% for 8 hours, and then demolded to produce a molded body.

(27) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 2

(28) A molded body was produced in the same manner as in Example 1 except that the proportion of the fiber was changed as shown in Table 2.

(29) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 3

(30) A molded body was produced in the same manner as in Example 1 except that the amorphous ratio of the aluminosilicate source was changed as shown in Table 2.

(31) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 4

(32) A molded body was produced in the same manner as in Example 1 except that the average particle diameter of the aluminosilicate source, and the proportion of the aluminosilicate source having an average particle diameter of 10 μm or smaller were changed as shown in Table 2.

(33) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 5

(34) A molded body was produced in the same manner as in Example 1 except that the type of the fiber was changed as shown in Table 2.

(35) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 6

(36) An alkali metal compound in an amount shown in Table 2 was dissolved in water to prepare an aqueous solution of the alkali metal compound. This aqueous solution and an aluminosilicate source in an amount shown in Table 2 were put into a stirring type heat-resistant container, stirred at 120° C. for 4 hours, and then cooled to room temperature (25° C.) to form a precursor. This precursor, a calcium ion source and sand in amounts shown in Table 2 were put into a mortar mixer, mixed for 3 minutes, then fibers aligned and converged in one direction in an amount shown in Table 2 were put into a mortar mixer, and mixed for another 1 minute to prepare a curable composition. The obtained curable composition was poured and filled into a mold of 6 cm in width×25 cm in length×1 cm in thickness, cured under normal pressure at 80° C.×RH90% for 8 hours, and then demolded to produce a molded body.

(37) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 7

(38) A molded body was produced in the same manner as in Example 1 except that the proportion of the calcium hydroxide was changed as shown in Table 2.

(39) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 8

(40) A molded body was produced in the same manner as in Example 1 except that the average particle diameter of the aluminosilicate source, and the proportion of the aluminosilicate source having an average particle diameter of 10 μM or smaller were changed as shown in Table 2.

(41) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 9

(42) A molded body was produced in the same manner as in Example 1 except that type II fly ash was used instead of volcanic ash produced in Kagoshima.

(43) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Example 10

(44) A molded body was produced in the same manner as in Example 1 except that the alkali resistant fiber was changed from PVA1 to PVA2.

(45) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 1

(46) A molded body was produced in the same manner as in Example 1 except that the alkali resistant fiber was not added.

(47) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 2

(48) A molded body was produced in the same manner as in Example 1 except that the alkali metal compound was not added.

(49) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 3

(50) A molded body was produced in the same manner as in Example 1 except that the calcium ion source was not added.

(51) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 4

(52) A molded body was produced in the same manner as in Example 1 except that the average particle diameter of the aluminosilicate source, and the proportion of the aluminosilicate source having an average particle diameter of 10 μm or smaller were changed as shown in Table 2.

(53) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 5

(54) A molded body was produced in the same manner as in Example 1 except that the average particle diameter of the aluminosilicate source, and the proportion of the aluminosilicate source having an average particle diameter of 10 μm or smaller were changed as shown in Table 2.

(55) The obtained molded body was evaluated as described above. The results are shown in Table 2.

Comparative Example 6

(56) A molded body was produced in the same manner as in Example 1 except that volcanic ash produced in Kagoshima having physical properties shown in Table 2 was used as the aluminosilicate source.

(57) The obtained molded body was evaluated as described above. The results are shown in Table 2.

(58) TABLE-US-00001 TABLE 1 Average fiber Average fiber diameter Aspect ratio strength [μm] [—] [cN/dtex] PVA1 26 230 13.8 PVA2 38 210 12.5 PP 65 185 5.5

(59) TABLE-US-00002 TABLE 2 Aluminosilicate Calcium source ion source Proportion of Water- Alkali metal aluminosilicate granulated compound source having blast Water average particle furnace glass SiO.sub.2 Amorphous Average diameters Ca(OH).sub.2 slag NaOH # 1 Water Sand [% ratio particle of 10 μm or [parts [parts [parts [parts [parts [parts [parts by [% by diameter smaller [% by by by by by by by Type mass] mass] [μm] by mass] mass] mass] mass] mass] mass] mass] mass] Example 1 Volcanic ash 76 88 5 75 100 19 48 14 102 54 207 produced in Kagoshima Example 2 Volcanic ash 76 88 5 75 100 19 48 14 102 54 207 produced in Kagoshima Example 3 Volcanic ash 76 62 5 75 100 19 48 14 102 54 207 produced in Kagoshima Example 4 Volcanic ash 76 88 10 50 100 19 48 14 102 54 207 produced in Kagoshima Example 5 Volcanic ash 76 88 5 75 100 19 48 14 102 54 207 produced in Kagoshima Example 6 Volcanic ash 76 88 5 75 100 19 48 50 — 110 207 produced in Kagoshima Example 7 Volcanic ash 76 88 5 75 100 80 48 14 102 54 207 produced in Kagoshima Example 8 Volcanic ash 76 88 40 35 100 19 48 14 102 54 207 produced in Kagoshima Example 9 Type II fly 59 72 18 34 100 19 48 14 102 54 207 ash Example 10 Volcanic ash 76 88 5 75 100 19 48 14 102 54 207 produced in Kagoshima Compar- Volcanic ash 76 88 5 75 100 19 48 14 102 54 207 ative produced in Example 1 Kagoshima Compar- Volcanic ash 76 88 5 75 100 19 48 — — 130 207 ative produced in Example 2 Kagoshima Compar- Volcanic ash 76 88 5 75 100 — — 14 102 54 207 ative produced in Example 3 Kagoshima Compar- Volcanic ash 76 88 80 9 100 19 48 14 102 54 207 ative produced in Example 4 Kagoshima Compar- Volcanic ash 76 88 60 25 100 19 48 14 102 54 207 ative produced in Example 5 Kagoshima Compar- Volcanic ash 70 35 500 0 100 19 48 14 102 54 207 ative produced in Example 6 Kagoshima Alkali resistant fiber based on 100 Variation parts by coefficient Alkali resistant mass of of average Variation Dimen- fiber molded content Formation coefficient sional Aluminosilicate [parts body rate of of precursor Bending of bending Bending change source Convergence by [parts fiber (treatment strength strength toughness rate Type Type of fiber mass] by mass] [%] temperature) [N/mm.sup.2] [%] [Nmm] [%] Example 1 Volcanic ash PVA1 With 4 1.1 8 Without 15 13 1400 0.11 produced in Kagoshima Example 2 Volcanic ash PVA1 With 8 2.1 10 Without 20 15 2600 0.11 produced in Kagoshima Example 3 Volcanic ash PVA1 With 4 1.1 8 Without 12 12 1000 0.12 produced in Kagoshima Example 4 Volcanic ash PVA1 With 4 1.1 9 Without 11 13 950 0.12 produced in Kagoshima Example 5 Volcanic ash PP With 4 1.1 15 Without 10 18 1800 0.12 produced in Kagoshima Example 6 Volcanic ash PVA1 With 4 1.0 10 With 11 14 1000 0.12 produced in (120° C.) Kagoshima Example 7 Volcanic ash PVA1 With 4 0.9 8 Without 19 14 2200 0.10 produced in Kagoshima Example 8 Volcanic ash PVA1 With 4 1.1 10 Without 8 14 600 0.19 produced in Kagoshima Example 9 Type II fly PVA1 With 4 1.1 9 Without 15 14 1000 0.11 ash Example 10 Volcanic ash PVA2 With 4 1.1 6 Without 12 10 1600 0.12 produced in Kagoshima Compar- Volcanic ash — — — 0 — Without 12 9 60 0.12 ative produced in Example 1 Kagoshima Compar- Volcanic ash PVA1 With 4 1.0 9 Without 6 14 450 0.20 ative produced in Example 2 Kagoshima Compar- Volcanic ash PVA1 With 4 1.1 10 Without 7 11 520 0.25 ative produced in Example 3 Kagoshima Compar- Volcanic ash PVA1 With 4 1.1 11 Without 4 16 250 0.23 ative produced in Example 4 Kagoshima Compar- Volcanic ash PVA1 With 4 1.1 11 Without 7 16 530 0.21 ative produced in Example 5 Kagoshima Compar- Volcanic ash PVA1 With 4 1.1 10 Without 3 25 200 0.14 ative produced in Example 6 Kagoshima

(60) As shown in Table 2, the molded bodies according to the present invention formed from the curable compositions containing the specified aluminosilicate source, alkali metal hydroxide, calcium ion source and alkali resistant fiber respectively had high bending strength, high bending toughness, and a low dimensional change rate, i.e. high strength, high ductility, and excellent dimensional stability. Also, the molded bodies according to the present invention had a lower variation coefficient of the average fiber content and a lower variation coefficient of the bending strength. This means a little variation in the average fiber content and a little variation in the bending strength, and means that a molded body having a more stable quality was obtained.

(61) On the other hand, the molded body formed from the curable composition not containing the alkali resistant fiber (Comparative Example 1) had remarkably low bending toughness. The molded body formed from the curable composition not containing the alkali metal hydroxide (Comparative Example 2), the molded body formed from the curable composition not containing the calcium ion source (Comparative Example 3), and the molded bodies formed from the curable compositions not containing the specified aluminosilicate source in the present invention (Comparative Examples 4 and 5) had lower bending strength, lower bending toughness, and a higher dimensional change rate. The molded body formed from the curable composition not containing the specified aluminosilicate source in the present invention (Comparative Example 6) had remarkably low bending strength and bending toughness. In addition, the molded body in Comparative Example 6 had a high variation coefficient of the average fiber content and a high variation coefficient of the bending strength, i.e. a large variation in the average fiber content and a large variation in the bending strength. Such a molded body has lower quality stability.

INDUSTRIAL APPLICABILITY

(62) The molded body according to the present invention has incombustibility and fire resistance because a matrix of the molded body is an inorganic polymer. Furthermore, since the molded body according to the present invention is formed from a curable composition having good reactivity resulting from inclusion of the specified aluminosilicate sources, alkali metal hydroxide, calcium ion source, and alkali resistant fiber, and since the curable composition undergoes a reaction process using a combination of an alkali-silica reaction and a pozzolanic reaction, the molded body according to the present invention has high strength, high ductility, and excellent dimensional stability. Consequently, the molded body according to the present invention can be effectively used as e.g., but not particularly limited to, various construction materials such as building blocks, floor materials, wall materials, ceiling materials, partitions, roof materials, and roofing-tiles.