JP2810192B2 - Method for producing composite material and composite material thereby - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a high-strength composite material and a composite material thereby. More specifically, the present invention relates to a method for producing a high-strength composite material that can be used as an interior or exterior material as a building material, a structural material, or the like, and a composite material using the same.

2. Description of the Related Art Hydraulic materials represented by cement have been widely used as structural materials and building materials since ancient times. However, there is a problem that the hydraulic material has a pot life after contact with water, and is thus limited in terms of manufacturing work. As a solution, the present inventors have found that a high-strength composite material can be obtained simply by kneading, molding and drying a mixture comprising a non-hydraulic inorganic material, a water-soluble polymer and water, and have already filed a patent application.

Problems to be Solved by the Invention However, although the molded body mainly composed of this non-hydraulic inorganic material can easily obtain high strength only by drying, it causes distortion due to shrinkage during drying, and the dried cured body warps. There was a problem that.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention is characterized in that a composition comprising a non-hydraulic inorganic material, a water-soluble polymer having a softening point and water is kneaded, molded, dried, and then hot-pressed at a temperature equal to or higher than the softening point of the dried and cured product. And a method for producing a high-strength composite material. The term “softening point” as used herein refers to a temperature at which the value of the maximum deflection starts to increase when a three-point bending test is performed on a composite material that has been dried and then heated while changing the temperature.
Hereinafter, the present invention will be described in detail.

First, in the present invention, a non-hydraulic inorganic material is a material that does not harden simply by kneading with water, and specific examples thereof include blast furnace slag powder, silica fume, fly ash, silica sand, silica stone powder, calcium carbonate, Examples include inorganic fine particles such as talc, bentonite, clay, zeolite, perlite, diatomaceous earth, kaolin, alumina, titania, and zirconia. These may be used alone or in combination of two or more.

The water-soluble polymer that can be used is not particularly limited as long as it has a softening point due to heating. However, fine particles are preferable because it is desirable to dissolve uniformly and quickly within the kneading time. For example, the following water-soluble polymers can be used. That is, polyvinyl acetate derivatives such as partially hydrolyzed polyvinyl acetate, cationized polyvinyl alcohol, anionized polyvinyl alcohol, etc .; acrylics such as acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, and acryloylmorpholine. Amide-based monomers, hydroxypropylmethylcellulose, cellulose derivatives such as hydroxyethylcellulose, polyethylene oxide,
And 2-hydroxyethyl (meth) acrylate and 2-
Hydroxypropyl (meth) acrylate is a water-soluble polymer having -OH such as a homopolymer or copolymer.
Particularly preferred water-soluble polymers are polyvinyl acetate derivatives such as partially hydrolyzed polyvinyl acetate, cationized vinyl alcohol and anionized polyvinyl alcohol. The amount of the water-soluble polymer to be used is preferably 1 to 15% (weight ratio, the same applies hereinafter) with respect to the non-hydraulic inorganic material, and particularly preferably 3 to 10%. When the amount of the water-soluble polymer used is 1% or less, the mixture cannot be kneaded, or even if kneaded, the kneaded body tends to be brittle and the moldability in the subsequent process tends to be poor. The effect of the present invention is not significantly changed even if it is used at 15% or more, which is economically disadvantageous. The amount of water used depends on the type of non-hydraulic inorganic material and the type and amount of water-soluble polymer used and must be determined so that the mixture exhibits good kneading properties, but is generally 4 to 40%. Preferably it is 7 to 30%.

Next, the method for producing the high-strength composite material of the present invention will be described.
In the present invention, a non-hydraulic inorganic material, a water-soluble polymer, and water are used. These are firstly combined and roughly mixed by a kneader such as a paddle type mixer or a planetary mixer.
Next, kneading is performed, and kneading is performed using a device that gives a strong shearing force to coarse mixing, such as a ruder kneader, a pressure kneader, a roll kneader, a banbury mixer, a wet pan mixer, a mixing roll, a kneading machine, a bag mill, a screw. An extruder or the like is used. There is no particular limitation on the molding machine.
High pressure presses, (vacuum) extruders and the like are generally used. In particular, it is preferable to use a method capable of molding under reduced pressure, for example, a vacuum extruder, because a dried and cured product having higher bending strength and less variation in bending properties can be obtained. Although the process proceeds to drying after molding, unlike the case of using a hydraulic cement, the present invention does not require a curing step, and is characterized in that a dried and cured product having high strength can be obtained only by drying. There is no particular limitation on the drying temperature, and any temperature can be adopted, but drying is preferably performed at room temperature to 100 ° C. It is preferable to employ a method of gradually drying (preliminary drying) at room temperature and then heating and drying at a high temperature (for example, 80 ° C. to 100 ° C.) for 5 to 15 hours, because distortion accompanying drying can be reduced. In order to remove the strain accompanying shrinkage during drying of the high-strength composite material obtained in this way and obtain a high-strength composite material having a uniform surface, for example, sandwiching a metal plate having a flat surface, drying A method in which pressure is applied by a press machine heated to a temperature equal to or higher than the softening point temperature of the cured product can be employed. The pressing pressure at that time is usually 1 to 50 kg / cm ² in surface pressure. The treatment time is not particularly limited as long as the distortion can be corrected, but is preferably as short as possible in consideration of the production efficiency and the thermal stability of the polymer, and is generally from 5 minutes to 1 hour.
Here, the softening point of the dried and cured body refers to a temperature at which the value of the maximum deflection at the time of performing a three-point bending test at the various temperatures of the dried and cured body starts to greatly change.

The thus obtained high-strength composite material of the present invention has a uniform surface in which distortion generated during drying is corrected.
In addition, as a result of the three-point bending test, it has a high bending strength as in the case of the uncorrected one.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention should not be limited to these. In the examples, parts indicate parts by weight.

Example 1 As a non-hydraulic inorganic material, 90 parts of clay (manufactured by Kunimine Industry Co., Ltd .; NK-300), silica fume (average particle size: 0.
14 μm) 10 parts, partially hydrolyzed polyvinyl acetate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; K
H-17S) and a mixture consisting of 7 parts of water and 15 parts of water were kneaded with a two-roll kneader (manufactured by Kyoei Iron Works) under high shear to obtain a viscous dough. It is 10 cm wide and 4 m thick using a vacuum extrusion molding machine (Honda Ironworks Co., Ltd .; HDE-2 type).
m, and was extruded into a plate shape. Then, the molded product was cut with a knife to a length of 20 cm. The molded product thus obtained was placed in a hot-air dryer at 80 ° C. and dried for 18 hours. The obtained dried cured product was warped due to a difference in drying shrinkage between the upper and lower surfaces during drying, and the warpage was 3 to 5 cm. The amount of warpage referred to here is expressed as the distance between the opposite end and the flat plate when the drying plate is placed on a completely uniform flat plate and one end in the longitudinal direction of the dried and cured product is pressed. In order to examine the softening point of the dried and cured body obtained in this way by a three-point bending test, a sample for a three-point bending test with a width of 1.5 cm and a length of 8 cm from the less warped portion near the center of the dried and cured body Was cut out with a rotary diamond cutter. Using this sample, a three-point bending test was performed at a temperature of 30 ° C. to 200 ° C. in steps of 10 ° C., and the maximum deflection was measured. The three-point bending test was performed using Tensilon (manufactured by Orientec Co., Ltd.) under the conditions of a span of 6 cm and a test speed of 1 mm / min. The results are shown in FIG. From this result, it was found that the softening point of the dried and cured product was 50 ° C. Based on the results, the dried and cured body was subjected to hot press shaping. That is, the pre-heated and dried hardened body (warp size: 3.5 cm) was placed in a hot press machine set at 150 ° C., which is higher than the softening point temperature of the dried and hardened body, and the surface pressure was 20 kg / cm ^2. For 20 minutes. The warped size of the dried shaped body thus obtained was 0.5 mm. Further, the bending strength obtained by the three-point bending test at 30 ° C. was 910 kg, which was the same as before the shaping.

Example 2 In addition to using 100 parts of clay as a non-hydraulic inorganic material, 7 parts of polyacrylamide (manufactured by Nippon Kayaku Co., Ltd .; Kayafloc N-100) as a water-soluble polymer having a softening point, and 21 parts of water Was processed in the same manner as in Example 1 to obtain a dried and cured product. The magnitude of the warpage of the dried and cured product was in the range of 2.8 to 4.2 cm. When the softening point of the dried and cured product was measured in the same manner as in Example 1, the softening point of the dried and cured product was 150
° C. The results are shown in FIG. Then, put the pre-heated and dried hardened material (warp size: 3.8 cm) in a hot press machine set at 210 ° C, which is higher than the softening point temperature of the dried and hardened material, and apply a surface pressure of 20 kg / cm ² . Heat press shaping for 20 minutes. The warped size of the dried shaped body thus obtained was 0.2 mm. The bending strength obtained in the three-point bending test at 30 ° C. was 580 kg, which was the same as before shaping.

Example 3 90 parts of clay and 10 parts of silica fume (average particle size 0.14 μm) were used as the non-hydraulic inorganic material, and hydroxypropyl methylcellulose (manufactured by Matsumoto Yushi Co., Ltd .; Marpolose EMP-) was used as the water-soluble polymer having a softening point. H) In 7 parts,
Except that 30 parts of water were used, the same treatment as in Example 1 was performed to obtain a dried and cured product. The degree of warpage of this dried and cured body is 2.3 to 3.8
cm. When the softening point of the dried and cured product was measured in the same manner as in Example 1, it was found that the softened point of the dried and cured product was 120 ° C. The results are shown in FIG.
Therefore, the temperature of 180 ° C, which is higher than the softening point
The dried and cured body (warp size: 3.5 cm) which had been preheated and placed in a hot press machine set in the above was placed in the hot press machine and subjected to hot press shaping at a surface pressure of 20 kg / cm ² for 20 minutes. The size of the warp of the dried shaped body thus obtained was 0.1 mm. Further, the bending strength obtained by the three-point bending test at 30 ° C. was 290 kg, which was the same as before the shaping.

Comparative Example 1 90 parts of clay and 10 parts of silica fume (average particle size 0.14 μm) were used as a non-hydraulic inorganic material, and carboxymethyl cellulose (manufactured by Daicel Chemical Industries, Ltd .; CMC-) was used as a water-soluble polymer having no softening point. 1160) A dried and cured product was obtained in the same manner as in Example 1 except that 30 parts of water was used instead of 7 parts. The magnitude of warpage of the dried and cured product was in the range of 2.5 to 4.1 cm. When the softening point of the dried and cured product was measured in the same manner as in Example 1, it was found that this dried and cured product had no softening point. The results are shown in FIG. Place the dried and hardened body (warp size: 2.8 cm) preheated and placed in a heat press machine set at 180 ° C for confirmation, and contact pressure of 20 kg / cm ²
Cracked when pressed.

Effects of the Invention By performing hot press shaping at a temperature equal to or higher than the softening point of the dried and cured body, a high-strength composite material having a uniform and smooth surface can be obtained.

[Brief description of the drawings]

FIG. 1 to FIG. 4 show the relationship between the maximum deflection and the measured temperature when a three-point bending test is performed on the dried and cured body in a temperature atmosphere of 10 to 210 ° C. in steps of 10 ° C. .

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-156077 (JP, A) JP-A-50-138012 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B28B 3/02 B28B 11/10 C04B 26/02 B29C 47/00

Claims (2)

(57) [Claims] 1. A method comprising kneading, molding and drying a composition comprising a non-hydraulic inorganic material, a water-soluble polymer having a softening point and water, followed by hot press shaping at a temperature not lower than the softening point of the dried and cured product. A method for producing a high-strength composite material. 2. A high-strength composite material produced by the production method according to claim 1.