JPH0578181A - Production of clay-natural fiber composite porous substance - Google Patents

Abstract

PURPOSE:To provide a lightweight recoverable and reutilizable incombustible material, composed of only a nonpollution and environmental noncontamination raw material substitutive for expanded polystyrene which is a petroleum product and readily convertible into natural soil in its unavoidable disposal. CONSTITUTION:This material is a clay-natural fiber composite porous substance obtained by mixing natural or synthetic clay with natural fiber and water, providing a mixed sol, rapidly freezing the resultant mixed sol at >=1X10<-3>ml/sec freezing rate and drying the frozen sol without thawing the sol. The solid liquid weight ratio of the mixed sol is preferably >=1% to <=25%. In addition to the natural or synthetic clay and natural fiber, at least one of a water-soluble paste, a coloring mater or a perfume can be mixed with water. The porous substance has properties absent in expanded polystyrene, is strong and can be utilized as cushioning, incombustible heat insulating, sound absorbing, adsorbent, fruit freshness retaining, catalyst and deodorizing materials.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention can use the fibers of used waste paper as a raw material, and does not pollute the global environment during use or after use. The present invention relates to a method for producing materials that are friendly to the global environment, such as wood, sound absorbing material, adsorbing material, fruit freshness maintaining material, and catalyst material.

[0002]

2. Description of the Related Art So-called styrofoam (polystyrene) is widely used as a cushioning material, a heat insulating material, and a sound absorbing material because it is lightweight and inexpensive.
However, since its raw material is petroleum, it does not spontaneously decompose,
When incinerating after use, high heat is generated and the incinerator is damaged,
It is also a typical material for global environmental pollution such as releasing a large amount of carbon dioxide. In addition, since it has been pointed out as a social problem such as being left undisturbed and polluting rivers and beaches, the emergence of alternative cushioning materials, heat insulating materials, and sound absorbing materials has been awaited.

In view of the above situation, the present invention is composed of only pollution-free and environmentally-polluting raw materials that can replace expanded polystyrene of petroleum products, is recoverable and reusable, and is naturally soiled when it is unavoidably discarded. It is an object of the present invention to provide a method for producing a lightweight and non-combustible material that is easily converted.

[0004]

Means for Solving the Problems As a means for solving the above-mentioned problems, the present inventor has proposed Japanese Patent Application No. 62-62184 "Manufacturing of open-type fine porous clay clay bodies. The clay porous body obtained by the "method" is pollution-free, environmentally-friendly and lightweight, but paying attention to its weakness, the compression and bending strength of the clay porous body can be replaced by expanded polystyrene. In this regard, from the standpoint of pollution-free and environment-free pollution, a natural fiber reinforced clay porous body consisting of clay that constitutes natural soil and natural fibers that are easily biodegradable in the soil is used. Manufacturing research was conducted.

As a result, even if the waste paper fiber as the natural fiber is reused, it is sufficiently stronger than the expanded polystyrene, and if a small amount of water-soluble glue such as starch paste is further added, the clay natural fiber composite porous material has higher strength. It turns out that you get a body. In addition, since this clay / natural fiber composite porous body is composed mainly of clay minerals, the properties of clay minerals such as non-combustibility, adsorption of organic compounds, and catalytic ability are combined with the function of porous bodies to form expanded polystyrene. It was also found that it has a non-flammable property and can be used as a non-combustible heat insulating material, deodorizing material, and adsorbent.

That is, according to the present invention, natural or synthetic clay and natural fiber are mixed with water to prepare a mixed sol, and the mixed sol is rapidly frozen at a freezing rate of 1 × 10 ⁻³ ml / sec or more,
The gist is a method for producing a clay / natural fiber composite porous body, which is characterized by drying without melting.

The present invention will be described in more detail below.

[0008]

[Action]

In the present invention, first, natural or synthetic clay and natural fiber are used as raw materials and mixed with water to form a mixed sol.

The term "clay" as used herein means a natural or synthetic mineral called "clay mineral" in the classification of minerals and a substance which contains other silicate minerals or inorganic compounds as its main components, among which montmorillonite, beidellite, The most excellent raw materials are saponite, bentonite containing clay minerals of a type called smectite in the classification of minerals, and other silicate minerals containing them as a main component, and acid clay.

[0011] Natural fibers mean all fibrous substances of biological origin regardless of plant or animal origin. From the standpoint of effective use of resources, used waste paper or used cotton cloth is used. Excellent vegetable fiber.

The mixing ratio of clay and fiber can be arbitrarily selected according to the purpose of use of the clay / natural fiber composite porous material.
For example, the weight solid-liquid ratio is 5%, and the clay / fiber ratio is 9/1.
In the case of mixed sol of a certain degree, the compressive strength of the clay / natural fiber composite porous body produced by freeze-drying thereof is equivalent to that of expanded polystyrene. By increasing the solid-liquid ratio or the mixing ratio of fibers, a clay natural fiber composite porous body having higher strength can be manufactured.

Next, natural or synthetic clay and natural fiber are mixed with water to form a mixed sol. Specifically, for example,
Water is added to natural or synthetic clay by weight solid-liquid ratio of 1% or more 2
A sol of 5% or less is prepared. On the other hand, a fiber-dispersed liquid having a weight-solid ratio of 1% or more and 25% or less is prepared with natural fibers and water. can get.

The obtained mixed sol is rapidly frozen at a freezing rate of 1 × 10 ^-3 ml / sec or more and dried without melting the frozen body, that is, when ice is sublimated, clay-natural fiber composite porous The body is manufactured.

The freezing rate here is the volume of the sol (m
It is defined as the value of (l) divided by the time (seconds) required for freezing, and thus means the average time for a certain amount of sol to completely freeze. Lower limit of freezing rate (1 × 10 ^-3 ml / sec)
Is a rate that guarantees the quality of the clay / natural fiber composite porous body produced. Although a similar porous material can be obtained with this value or less, the size and shape of the pores become indefinite, and the properties of the porous material such as compressive strength deteriorate. To freeze the mixed sol, an appropriate freezing means can be used, and examples thereof include liquid nitrogen, a refrigerator, and heat of vaporization of natural gas.

If a water-soluble paste is added to the mixed sol of clay and natural fiber and the same manufacturing process as above is taken, the compressive strength of the clay / natural fiber composite porous body is further increased, and
Coloring or flavoring is possible by adding a coloring agent or a fragrance.
In short, it is possible to add an appropriate third component that does not lose the porosity, which is the basic property of the clay / natural fiber composite porous body.

Next, examples of the present invention will be described.

[0018]

[Example 1] Elutriation of natural pentonite from Yamagata Prefecture,
Only the mineral particles of 2 microns or less were collected to concentrate the montmorillonite, and the interlayer ions of the montmorillonite were replaced with Na + using an aqueous NaCl solution to obtain a clay raw material powder. on the other hand,
Peel off the paper pack from the milk container, take out only the pulp fiber part, and tear it into small pieces of about 10 cm ² by hand and boil it.
The fibers were disentangled with ultrasonic waves and a ball mill. The dissociated fiber was once dried for weighing and used as a raw material of the fiber.

Then, the raw materials of clay and natural fiber are individually weighed in a dry state, and pre-weighed water is added to each to disperse the clay sol and the natural fiber in a solid-liquid ratio of 10% in water. An aqueous solution was used.

The prepared clay sol and natural fiber-dispersed aqueous solution were weighed to adjust the clay / fiber ratio to 85/15, and both were mixed and stirred to obtain a clay / natural fiber mixed sol. The same mixed sol was filled in a cylindrical can made of aluminum (15φ, 30 mm) and immersed in liquid nitrogen. The freezing rate was 1 × 10 ⁻⁴ ml / sec. After freezing the whole amount, it was transferred to a vacuum dryer together with a can, and the ice was completely sublimated to obtain a clay / natural fiber composite porous body.

When the strength and buffering effect of the obtained porous material were examined, it was superior to expanded polystyrene, and there were no changes in various properties such as adsorption, surface smoothness and nonflammability of montmorillonite.

[0022]

Example 2 Water was added to the same clay raw material powder as in Example 1 to make a clay sol having a solid-liquid ratio of 5% by weight, while a used cotton cloth was ground and the fibers obtained were weighed. Then, it was dispersed in water to prepare a fiber dispersion aqueous solution having a solid-liquid ratio of 5%, and both were mixed to obtain a clay / fiber mixed sol. The same mixed sol was rapidly frozen and vacuum dried in the same manner as in Example 1 to obtain a clay using cotton fiber.
A natural fiber composite porous body was obtained. The properties of the obtained porous body were almost the same as those in Example 1, although the compressive strength was poor.

[0023]

[Example 3] A clay / fiber mixed sol having a solid-liquid ratio of 10% was prepared by the same raw material, formulation and process as in Example 1, and frozen in a domestic freezer at a freezing rate of 5 x 10 ^-2 ml / sec. .. The frozen body was vacuum dried by the same process as described in Example 1 to obtain a clay natural fiber composite porous body. The shape of the pores of the porous body was generally flat and mixed with large pores having a diameter of several mm to sometimes several cm. Therefore, it does not function as a foam polystyrene substitute cushioning material, which is the object of the present invention, and the lower limit of the freezing rate in the claims can be set accordingly.

[0024]

Example 4 Chemical reagents in powder form, Al ₂ O ₃ , MgO, Si
O ₂ and Na ₂ O are weighed and mixed with the ideal composition of dehydrated montmorillonite, and the powder mixture is melted and rapidly cooled to prepare glass of the same composition, which is crushed and sealed with water in a platinum tube, Synthetic montmorillonite was obtained by hydrothermal treatment at 350 ° C. and 1000 atm.

After drying the obtained montmorillonite, it was weighed and water was added again to prepare a montmorillonite sol having a solid-liquid ratio of 10%. A dispersion of the paper pulp fibers used in Example 1 (solid-liquid ratio 10%) was added to this sol at a ratio of 85:15 to prepare a clay / fiber mixed sol.

The resulting mixed sol was rapidly frozen and vacuum dried in the same steps as in Example 1 to obtain a clay / natural fiber composite porous body. In terms of various properties such as compressive strength, heat insulation, and pore size and size, this porous body is a clay natural fiber composite porous body made from montmorillonite obtained by elutriating the natural pentonite used in Example 1. Although it was almost the same, it was more excellent in that it was white and slightly higher in compression strength.

[0027]

[Example 5] The Pentonite produced in Yamagata Prefecture used in Example 1 was crushed as it was without elutriation, dried, and then weighed to add water to prepare a clay sol having a solid-liquid ratio of 10%. .. A dispersion of the paper pulp fibers used in Example 1 (solid-liquid ratio 1
0%) was added at a ratio of 85:15 to prepare a clay / natural fiber mixed sol.

The obtained mixed sol was rapidly frozen and vacuum dried in the same steps as in Example 1 to obtain a clay / natural fiber composite porous body. This porous body was brownish gray and had a compressive strength of Example 1.
Although it was inferior to the porous body of No. 3, it had a property as a porous body which can be sufficiently replaced with expanded polystyrene.

[0029]

As described in detail above, according to the present invention,
The following excellent effects are obtained.

It is possible to produce a clay / natural fiber composite porous body which is made of clay and natural fibers which are pollution-free and environment-free and which is as lightweight as expanded polystyrene and has a higher strength.

The clay / natural fiber composite porous material can replace expanded polystyrene in many applications, but if the porous material is left as a product in a natural environment, the clay will return to the soil and the natural fiber will be decomposed by microorganisms. Since it is easily decomposed into soil organic matter, it can be provided as a new material suitable for the global environment. This effect is remarkable in comparison with the fact that after use, expanded polystyrene, which must be incinerated, generates a high temperature upon incineration and produces a large amount of carbon dioxide gas.

Clay based on freeze-drying of mixed sol
Since the natural fiber composite porous body can be returned to the mixed sol by using water after the production method, it is an industrial material with extremely high resource utilization efficiency.

Clay, which is the main raw material, is usually produced in volcanic ash soils or tuffs in Japan, so it is possible to effectively utilize unused resources, and the other main raw material, natural fiber, is used waste paper. Alternatively, since the fibers of the cotton cloth can be used, the role of effective use of resources is extremely large.

For rapid freezing of the mixed sol, a low heat source generated when the natural gas stored in a liquid is stored and vaporized can be used, so that resources can be effectively used in the manufacturing process.

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[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The prepared clay sol and natural fiber-dispersed aqueous solution were weighed to adjust the clay / fiber ratio to 85/15, and both were mixed and stirred to obtain a clay / natural fiber mixed sol. The same mixed sol was filled in a cylindrical can made of aluminum (15φ, 30 mm) and immersed in liquid nitrogen. The freezing rate was 1 × 10 ^-2 ml / sec . After freezing the whole amount, it was transferred to a vacuum dryer together with a can, and the ice was completely sublimated to obtain a clay / natural fiber composite porous body.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

[0023]

[Example 3] A clay / fiber mixed sol having a solid-liquid ratio of 10% was prepared by the same raw materials, blending and steps as in Example 1, and was frozen in a domestic freezer at a freezing rate of 5 x 10 ^-4 ml / sec . .. The frozen body was vacuum dried by the same process as described in Example 1 to obtain a clay natural fiber composite porous body. The shape of the pores of the porous body was generally flat and mixed with large pores having a diameter of several mm to sometimes several cm. Therefore, it does not function as a foam polystyrene substitute cushioning material, which is the object of the present invention, and the lower limit of the freezing rate in the claims can be set accordingly.

Claims (3)

[Claims] 1. A natural or synthetic clay and natural fiber are mixed with water to prepare a mixed sol, and the mixed sol is 1 × 10 ⁻³ ml.
A method for producing a clay / natural fiber composite porous body, which comprises rapidly freezing at a freezing rate of not less than 1 sec / second and then drying without melting. 2. The method according to claim 1, wherein the mixed sol has a weight solid-liquid ratio of 1% or more and 25% or less. 3. In addition to natural or synthetic clay and natural fibers,
The method according to claim 1 or 2, wherein at least one of water-soluble paste, pigment or fragrance is mixed with water.