JP2569427B2 - Agar clay composite porous body and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous agar clay composite and a method for producing the same. More particularly, the present invention relates to a porous agar clay composite body suitable for a cushioning material, a heat insulating material, a sound absorbing material and the like in consideration of global environmental protection, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, cushioning materials, heat insulating materials,
Or, as a sound absorbing material, expanded polystyrene (styrene foam), urethane foam, or styrene paper,
It is widely and commonly used because of its large volume and low cost. However, these expanded polystyrene, styrene paper, etc. are made from petroleum oil artificially collected from the deep crust, and as a result, a large amount of carbon dioxide is generated during incineration after use, which is a typical pollutant of the global environment. Material.

[0003] Further, these expanded polystyrene, styrene paper, and the like may be destroyed in an incinerator due to high heat during incineration. Furthermore, these materials are often discarded and left on rivers and beaches after use, polluting rivers and beaches and causing serious environmental problems.

Under such circumstances, materials compatible with the global environment that can be substituted for expanded polystyrene, styrene paper, and the like suitable for cushioning materials, heat insulating materials, sound absorbing materials, and the like have been studied. These materials are still in the experimental study stage, and none have been put to practical use. This invention solves the above-mentioned drawbacks of the prior art, is made of only materials compatible with the global environment, is easy to collect and reuse, and is easily reduced to natural soil and disposed of in ecosystems upon disposal. It is an object of the present invention to provide a new material suitable for use as a cushioning material, a heat insulating material, a sound absorbing material, and the like, and a manufacturing method thereof.

[0005]

According to the present invention, a mixed sol of an agar solution and a clay sol is rapidly frozen at an average freezing speed of 1 × 10 ⁻² ml / sec or more. Next, there is provided an agar clay composite porous material comprising a dried porous material.

Further, the present invention relates to an agar clay mixed sol obtained by mixing an agar aqueous solution and a clay sol with a 1 × 10
The present invention also provides a method for producing a porous agar clay mixed material, characterized by rapidly freezing at an average freezing speed of ^-2 ml / sec or more, and then drying the frozen material without melting to obtain a porous material.

The inventor of the present invention has conducted intensive studies to achieve the above object, and as a result, has frozen a mixture of an aqueous agar solution and a clay sol, and vacuum-dried the frozen body without melting it. The present inventors have found that a novel earth-friendly material can be obtained, and that the compressive strength can be controlled by changing the mixing ratio of agar solution and clay sol. is there.

In the present invention, after the agar clay mixed sol obtained by mixing the agar solution and the clay sol is frozen,
The frozen body is dried in a vacuum without being thawed to prepare a porous agar clay.

Examples of the clay that can be used in the present invention include natural clays such as montmorillonite, saponite, beidellite, kaolinite, allophane and bentonite, and synthetic clays obtained by synthesizing these clays. Agar is known as a natural complex polysaccharide substance, and its aqueous solution can be used at an appropriate concentration. Preferably, it is at least 5% by weight.

The same applies to the concentration of clay sol. On the other hand, the mixing ratio of the agar solution to the clay sol is 10 /
When it is 90 or more, a porous body having high compressive strength can be obtained. In freeze-drying, it is essential to rapidly freeze at an average freezing rate of 1 × 10 ⁻² ml / sec or more. By this rapid freezing, a high-quality porous body having micropores on the order of microns can be obtained. If it is less than 1 × 10 ⁻² ml / sec, the pores of the porous body become too large, and the strength is significantly reduced.

In the present invention, natural fibers, pigments and / or fragrances dispersed in water can be added depending on the application.

Hereinafter, the present invention will be described in more detail with reference to the following examples. Of course, the present invention is not limited by the following examples.

[0013]

EXAMPLES Example 1 and Comparative Example 1 Natural bentonite from Sazawa, Yamagata Prefecture was elutriated, and only montmorillonite components were concentrated by collecting only mineral particles of 2 μm or less.
The interlayer ion of montmorillonite was replaced with Na ⁺ using an aqueous NaCl solution, washed with water and dried to obtain a clay raw material. The clay raw material and water were weighed and mixed to prepare a clay sol having a solid / liquid ratio of 1: 9, and left to stand for a day to ripen. The agar was a commercially available powder, weighed so that the solid / liquid ratio was 1: 9, mixed with water, and dissolved by heating.

Next, the ratio of agar solution / clay sol was adjusted to 90/10, 80/20, 70/30, 60, respectively.
/ 40, 50/50, 40/60, 30/70, 20 /
It was adjusted to 80, 10/90, and the agar solution and the clay sol were mixed while heating.

The mixed sol is placed in a stainless steel container, the container is immersed in liquid nitrogen, and the average freezing rate is set to 1 × 1.
0 rapidly frozen as ^-2 ml / sec or more. After this,
The frozen body was dried under vacuum to prepare a porous body in which fine pores were formed. The shape of the porous body can be formed into various shapes such as a lump and a rod according to the shape of the container. For comparison, a porous body was prepared only from a clay sol having a mixing ratio of 0/100. The porous body was taken out of the container and the compression strength was measured. Compressive strength increased with increasing agar content. Except for the porous body (Comparative Example 1) made only of clay sol, the compressive strength was equal to or higher than that of commercially available expanded polystyrene. Further, all the porous bodies having a mixing ratio of agar solution / clay sol of 20/90 or more exceeded the compressive strength of commercially available expanded polystyrene.

Example 2 A natural bentonite produced in Sazawa, Yamagata Prefecture was ground without elutriation, and only mineral particles of 5 μm or less were collected by air classification to obtain a clay raw material. This clay raw material was weighed with water and then mixed to prepare a clay sol having a solid / liquid ratio of 2: 8, and left to stand for a day and aged to mature. As for agar, the same commercially available powder as in Example 1 was used, weighed such that the solid / liquid ratio was 1: 9, mixed with water, and heated to dissolve. Next, the mixing ratio of the agar solution / clay sol was adjusted to 10/90, and the agar solution and the clay sol were mixed while heating.

The mixed sol is placed in a stainless steel container, the container is immersed in liquid nitrogen, and the average freezing rate is 1 × 10
Rapidly frozen at> ⁻² ml / sec. Thereafter, the frozen body was vacuum-dried to form a porous body in which fine pores were formed. Next, the porous body was taken out of the container, and the compressive strength was measured. The compressive strength exceeded that of commercially available expanded polystyrene.

Example 3 Using the same agar solution and clay sol as in Example 1, a mixed sol having a mixing ratio of aqueous agar solution / clay sol of 50/50 was colored with red paint. Then, this was put in a stainless steel container, and the container was immersed in liquid nitrogen, and rapidly frozen at an average freezing rate of 1 × 10 ⁻² ml / sec or more. Then, the frozen body was vacuum-dried to prepare a porous body in which fine pores were formed. When the porous body was taken out of the container and the compressive strength was measured, the obtained porous body was found to have a mixing ratio of 50% aqueous agar / clay sol that was not colored with paint.
The strength was almost the same as that of a porous body molded from a mixed sol of / 50.

COMPARATIVE EXAMPLE 2 Using the same agar solution and clay sol as in Example 1, a mixed sol having a mixing ratio of aqueous agar solution / clay sol of 50/50 was placed in a stainless steel container, and this container was placed in a household refrigerator. Put into a freezer and set the average freezing rate to 1 × 10 ⁻² ml /
The mixed sol was frozen by slow cooling at a rate much slower than a second. Next, the frozen body was vacuum-dried to form a porous body. When this porous body was taken out of the container, the obtained agar clay composite porous body had a width of 0.1 mm and a length of several m.
The lens-shaped holes of m were aligned, and had very low strength.

[0020]

As described above in detail, the agar clay mixed porous body of the present invention is made of only a material compatible with the global environment, and can be easily reduced to natural soil when discarded. In addition, this porous body has a compressive strength equal to or higher than that of conventional expanded polystyrene or the like, and can be replaced with expanded polystyrene, styrene paper, etc., which are widely used as cushioning materials, heat insulating materials, sound absorbing materials, and the like. is there.

Claims (5)

(57) [Claims] An agar clay composite porosity characterized in that a mixed sol of an aqueous agar solution and a clay sol is rapidly frozen at an average freezing speed of 1 × 10 ⁻² ml / sec or more, and then dried to form a porous body. body. 2. The agar clay composite porous body according to claim 1, further comprising a natural fiber, a pigment, and / or a fragrance. 3. An agar clay mixed sol obtained by mixing an aqueous agar solution and a clay sol is rapidly frozen at an average freezing speed of 1 × 10 ⁻² ml / sec or more, and then the frozen body is dried without being thawed. A method for producing a porous clay containing agar clay, comprising: 4. The method of claim 3, wherein the mixing ratio of the agar solution is 10/90 or more with respect to the clay sol to mix the agar solution and the clay sol. 5. The method according to claim 3, wherein a natural fiber, a pigment, and / or a fragrance dispersed in water are mixed and freeze-dried.