JPH08302059A - Inorganic lightweight molding - Google Patents

Abstract

PURPOSE: To obtain a lightweight molding having flexibility by using a cement, a wood chip cement, slate waste powder, etc., and an inorganic compound such as silas balloon, etc., as raw materials. CONSTITUTION: This inorganic lightweight molding comprises a composition consisting of an inorganic compound, a water-soluble polymer compound having 10-300MPa tensile strength of a coating film, 30-65mN/m surface tension in 0.4wt.% aqueous solution at 20 deg.C and containing two or more hydroxy groups in one molecule, a water-soluble polymer compound containing one or more carboxyl groups or sulfone groups in one molecule and/or an anionic surfactant and a polymer compound having 0.1-10MPa tensile strength of a coating film, 200-2,000% elongation at break, -40 to 30 deg.C second-order transition temperature and 30-200cal/cc cohesive energy, contains >=50wt.% of the inorganic compound and has <=0.4g/cm<3> apparent density.

Description

Detailed Description of the Invention

[0001]

The present invention relates to water-insoluble carbonates such as calcium carbonate and barium sulfate, sulfates, phosphates, cements, water-insoluble oxides such as magnesia, zirconia and ferrite, talc, The present invention relates to an inorganic light-weight molded product having open cells, which is mainly composed of rocks such as jammon rock, clay minerals such as kaolin, montmorillonite, and pyrophyllite, and which has open cells.

[0002]

Inorganic compounds used in the present invention are:
Each of them has a specific gravity of 2 to 6, and the molded product is heavy, brittle, and particularly weak in bending. Therefore, although it is commercialized as a wood chip cement, a slate, etc. by blending an organic or inorganic fibrous material, the drawback of being heavy remains.

Further, since the features of the molded products of these inorganic compounds are heat resistance and nonflammability, it is difficult to keep these features and provide weight reduction and flexibility. Has not appeared yet.

[0004]

DISCLOSURE OF THE INVENTION The present invention is not limited to fibrous materials, and can be used as a raw material for an inorganic compound of any shape, that is, powdery, granular, acicular, scale-like, etc., which is not entangled, and is lightweight and lightweight. Various compounds to be added to the inorganic compound for the purpose of obtaining a molded article having flexibility and the compounding ratio thereof are examined.

The present inventor has previously found in Japanese Patent Application No. 6-221475 that a lightweight molded product having an open cell structure with a lignocellulose content of 50% by weight or more can be obtained.
In the same way, we tried to reduce the weight by using a cell structure, but when the content of inorganic compounds was 50% by weight or more, the apparent density was 0.4 g / cm ³
The following uniform cell structure could not be obtained, and the target molded product could not be obtained.

For example, using cement powder (specific gravity 3.15), the content of cement is 54% by weight, 60% by weight,
At 70% by weight, only a cracked sheet was obtained at an apparent density of 0.4 g / cm ³ or less, and a clean sheet was obtained only at an apparent density of 0.45 to 0.5 g / cm ³ . Also, with 37% by weight of cement, a sheet having a uniform apparent density of 0.37 g / cm ³ with a cell structure was obtained with a composition of 63% by weight of binder and mainly composed of an organic polymer.

However, the amount of the binder to be added needs to be reduced as much as possible because the amount of the organic substance that can be used in combination is limited in the use of the molded product of these inorganic compounds. Therefore, in order to obtain a molded product having an inorganic compound content of 50% by weight or more and having an apparent density of 0.4 / cm ³ or less, another method that does not rely on a binder is necessary. The present invention has been studied by taking the above points into consideration.

[0008]

[Means for Solving the Problems] In the case of forming a molded product by binding a powdery or granular material of any shape of an inorganic compound with a binder as small as possible while maintaining a homogeneous cell structure, the inorganic compound is wetted rather than a dry method. A wet method using water as a solvent is preferable. Since an adhesive which is soluble or emulsified in water is used in the production thereof, it is necessary to prevent migration of these adhesives to the surface when heating and evaporating water during molding. Further, in order to form a cell structure, air must be blown into the slurry of the inorganic compound and dried while retaining the finely dispersed cells in the slurry. A fine cell structure cannot be obtained. The following measures were adopted to achieve these objectives.

That is, (1) the tensile strength of the coating is 10 MPa (megapascal) or more, preferably 30 or more and 300 MPa, and the surface tension of a 0.4% by weight aqueous solution at 20 ° C. is 65 mN / m (millinewton / meter) or less 30 mN / m, a water-soluble polymer compound having two or more hydroxyl groups (hereinafter abbreviated as OH groups) in one molecule is 10% by weight or less and 0.5% by weight or less with respect to the inorganic compound.
Within the range of (2) a water-soluble polymer compound having two or more carboxyl groups or sulfone groups in one molecule or /
And an anionic surfactant are preferably in the range of 20% by weight or less and 1% by weight with respect to the inorganic compound, (3) the tensile strength of the film is 10 MPa or less and 0.1 MPa, preferably 6 or less and 0.5 MPa, and the elongation at break. 2,000% or less 200%, preferably 1,800%
In the following range of 300%, second-order transition temperature (hereinafter abbreviated as Tg) 30 to -40 ° C, preferably 10 to -20 ° C, and cohesive energy density 20 to 200 (cal / cc), preferably 60 to 120 (cal / c
c) the polymer compound is preferably an inorganic compound,
Mix in the range of 5 to 100% by weight to make a slurry with water as a solvent, blow air while stirring it, and then mold it into a sheet or inject it into the mold to heat and evaporate the water to mold it. To do.

Examples of the water-soluble polymer compound (1) include polyvinyl alcohol (abbreviated as PVA) derivatives and cellulose derivatives. The derivative is an etherification copolymer or an acetalization copolymer of an alcohol or aldehyde having an alkyl group having 1 to 8 carbon atoms. The preferable addition amount is 1 to 3% by weight with respect to the inorganic compound, but if it is present in excess, it causes non-uniform cell structure and unmoldable.
Do not exceed% by weight.

As the water-soluble polymer compound having two or more carboxyl groups or sulfone groups in one molecule of (2), polyacrylic acid and its derivative, polymethacrylic acid and its derivative, and a copolymer of maleic acid. , Carboxymethyl cellulose (CMC), sodium alginate, sodium polyvinyl sulfonate, and the like. Examples of anionic surfactants include fatty acid soda, higher alcohol sulfate ester salts, and alkylbenzene sulfonates. It was found that these improve the fluidity of the slurry containing air bubbles and, at the same time, are effective in preventing the migration of the polymer compound onto the surface of the molded product during heat molding. Therefore, the evaporation rate of water during heat molding can be increased, and the drying time can be shortened. In this case, too, there is an optimum addition amount, which is 0.5 to 20% by weight, preferably 0.5 to 10% by weight, and not more than 20% by weight of the inorganic compound, either individually or in combination. On the other hand, if more than that amount is added, the structure of the bubbles becomes non-uniform and the fluidity of the slurry decreases.

As the polymer compound serving as the adhesive of (3), for example, a styrene-butadiene copolymer (SBR) having a butadiene content of 35% by weight or more, a methyl methacrylate-butadiene copolymer (MBR). Ethylene-vinyl acetate copolymer having an ethylene content of 5 to 50% by weight (EVA
C), vinyl acetate-acrylic acid ester copolymers, vinyl acetate-vinyl ester copolymers and vinyl acetate-vinyl ether copolymers having a vinyl acetate content of 80% by weight or less.

Even if only three components (1), (2) and (3) are added to an inorganic compound, a molded product having an apparent density of 0.4 g / cm ³ or less and an inorganic compound content of 50% by weight or more can be obtained. Absent. As a result of various studies, the volume ratio of all inorganic compounds in the molded product was determined.
If it is 20% or more and the apparent volumetric shrinkage rate (S) defined by the following formula when heating and drying the slurry containing bubbles is 30% or less, preferably 25% or less It was found that a crack-free molding was obtained. Assuming that the density of the molded product when S = 0 is C ₀ and the density of the actually molded product is C ₁ , S at that time is as follows.

S (%) = (1-C ₀ / C ₁ ) × 100

Here, C ₀ can be calculated by the following equation. C ₀ = (density of slurry holding air bubbles) × (solid content of slurry before blowing air)

As a method for reducing the S obtained in this way to 30% or less, the particle size is 5 to 1,000 μm, preferably 10 to 500.
The total volume ratio of inorganic balloons having a particle size of μm and a bulk specific gravity of 0.8 or less, preferably 0.5 or less is 20 in the molded product.
% Or more to be added.

Examples of the inorganic balloons include silicic acid type silas balloons, glass balloons, silica balloons, fly ash balloons, perlite and vermiculite, and non-silicic acid type alumina, zirconia and carbon balloons.

In this way, the apparent density of the inorganic compound and the inorganic balloon is 50 g or more and the apparent density is 0.4 g / cm.
A molded product having uniform open cells of ₃ or less is obtained.

At least four components as described above are added to water and mixed well, and then air is blown into the slurry to foam. The water content and viscosity of the slurry are, of course, the same slurry, but the size and dispersion state of the bubbles change depending on the stirring speed when air is blown in. However, if these conditions are made constant, the action of each of the above-mentioned components makes it constant. A molded product having a cell structure can be obtained.

The slurry containing air bubbles is molded by evaporating water in a dryer. At that time, if the Teflon sheet or the sheet surface-treated with Teflon is dried on a belt or a mold coated with a release agent, the molded product can be easily taken out. Further, a continuous foaming-based sheet can be obtained by continuously discharging a slurry having bubbles on an endless sheet, and drying and taking out the slurry. Also, on sheets or films of materials that are well wetted by the slurry, such as paper, woven cloth, non-woven mortar, glass fiber mats, wooden boards, plastic boards or sheets, metal boards such as aluminum boards and steel sheets, metal foils such as aluminum. It is also possible to perform integral molding by laminating lignocellulosic foams.

Further, if the content of the inorganic substance is 50% by weight or more, organic fibrous substances (for example, natural fibers such as wool, cotton and hemp, various organic synthetic fibers), and various shapes of lignocellulose (fibrous, rod-like, powdery, (Scaly, etc.) can be mixed.

In addition to the above components of the inorganic lightweight molded article,
A compound having two or more functional groups capable of chemically bonding with an OH group or a carboxyl group in one molecule may be contained in an amount of 0.5 to 2.0% by weight of the organic content in the composition of the molded product. Examples of such organic compounds include glyoxal, trimethylolmelamine, and tris (2-hydroxyethyl) -isocyanurate.

Further, if the surface of the molded article of the present invention is treated to be water-repellent with a fluororesin or the like, waterproofness can be imparted, and if necessary, various additives such as aromatic agents,
Antifungal agents, antibacterial agents, coloring agents and the like can be added appropriately within a range that does not impair the properties of the molded product.

[0024]

The inorganic compound, for example, Portland cement powder, forms the skeleton of the molded product together with the inorganic hollow balloon described later. The balloon of the inorganic hollow body contributes to the weight reduction of the molded product, and contributes to the improvement of the mechanical properties of the lightweight molded product together with the dry film of the organic binder entraining air bubbles.

The water-soluble polymer compound having an OH group in the molecule, such as PVA, is 10% by weight or less to 0.5% by weight.
Addition within the range contributes to stabilization of bubbles in the foaming process and an increase in mechanical strength. For that purpose, the tensile strength of the film must be at least 10 MPa or more, and in order to stabilize the bubbles, the surface tension of a 0.4 wt% aqueous solution of the polymer compound is 65 mN / m or less, which is smaller than that of water. The smaller the value, the better the results obtained, but the water-soluble polymer that precipitates in water at 30 ° C or higher loses bubble stability.

As the polymer component, in addition to the polymer as the adhesive and the polymer component as the bubble stabilizer,
It is a water-soluble polymer having two or more COOH groups in the molecule, which functions to control and improve the fluidity before molding and prevent migration of the adhesive or bubble stabilizer. For example, polyacrylic acid, CMC and the like. Further, the anionic surfactant acts similarly, and when mixed with a polymer such as polyacrylic acid, it is useful for improving fluidity and preventing migration.

The inorganic lightweight molded product of the present invention is composed of the above-mentioned inorganic compound, inorganic balloon, and three specific water-soluble polymer compounds, and glyoxal or trimethylolmelamine as a material to be added if necessary. And the like form crosslinks by chemical bonds with the above-described polymer having an OH group or a COOH group, and further improve the water resistance of the molded product. Clay minerals such as kaolin and bentonite are also useful for flame retardancy and hardness control. As described above, the fluorine-based or silicone-based resin coating contributes to imparting water repellency and water resistance to the surface.

The composition having the above-mentioned composition has a good physical property as a lightweight molded product having an apparent density of 0.4 g / cm ³ or less even if the inorganic compound or the inorganic balloon is 50% by weight or more. can get. Where the total inorganic volume ratio is 20
% Or more, the apparent volumetric shrinkage ratio (S) during heat drying is 30
When it is at most%, a molded product free from cracks can be obtained in a non-organic solvent system (water system).

[0029]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Example 1 Styrene-butadiene copolymer latex having a solid content concentration of 48% by weight (hereinafter abbreviated as SBR) (the styrene content of the copolymer is about 56% by weight) 104 g, 10% by weight of PVA-217E (manufactured by Kuraray Co., Ltd.) , 0.4% surface tension 51mN / m) aqueous solution 10g, 1
0% by weight of Isoban 104 (manufactured by Kuraray Co., Ltd., isobutylene-maleic anhydride copolymer) 6 g of an aqueous solution and 120 g of water were mixed in a solution of Portland cement powder (specific gravity 3.15) 80
g, Shirasu balloon (average particle size 0.1 mm, bulk specific gravity 0.4) 40 g, and agitated with a household mixer for 10 minutes to create a foamed slurry.
(Apparent density 0.65 g / cm ³ ) was dried and molded on a Teflon sheet at 75 ° C. to obtain a foamed sheet having a thickness of 5 mm. This sheet was a sheet having a uniform cell structure and an apparent density of 0.34 g / cm ^{3 with} no crack and good surface property. The apparent volumetric shrinkage during molding of the sheet was 8.8%, the total inorganic mass of the molded sheet was 70% by weight, and the volumetric ratio was 25%.

Comparative Example 1 Portland cement powder without addition of Shirasu balloon
The procedure was exactly the same as in Example 1 except that 120 g was added. Slurry holding air bubbles (apparent density 0.62 g / cm
^The foamed sheet molded from ³ ) has an apparent density of 0.55 g / cm
^{At 3,} it had large and small cracks. In this case, the apparent volumetric shrinkage rate at the time of molding was as large as 46%, and the inorganic volumetric rate of the molded sheet was 12%.

Example 2 78 g of SBR having a solid content of 48% by weight and 10% by weight of PVA
-420 (Kuraray Co., Ltd., 0.4% surface tension 47 mN / m)
Aqueous solution 7.5 g, 10 wt% Isoban 104 aqueous solution 4.5 g, water 9
To a solution prepared by mixing 6 g, 45 g of crushed powder of wood chip cement plate (average particle size 300 μm) and 45 g of shirasu balloon (average particle size 0.1 mm, bulk specific gravity 0.3) were added and stirred with a household mixer for 10 minutes to foam. The apparent density of the slurry was 0.38 g / cm ³ , and this was dried on a Teflon sheet at 85 ° C. to obtain a good foamed sheet having a thickness of 5 mm and an apparent density of 0.22 g / cm ³ . In this case, the apparent volumetric shrinkage during molding was 21%, the total inorganic mass of the molded sheet was 70% by weight, and the inorganic volume ratio was 21%.

Comparative Example 2 The same procedure as in Example 2 was carried out except that wood particles and 90 g of cement powder were added without using Shirasu balloon. The sheet formed from the slurry holding air bubbles (apparent density 0.39 g / cm ³ ) had an apparent density of 0.43 g / cm ³ , and only a sheet with many cracks was obtained. In this case, the apparent volumetric shrinkage rate at the time of molding was 43%, and the inorganic volumetric rate of the molded sheet was 10%.

Example 3 Ethylene-vinyl acetate copolymer emulsion having a solid content concentration of 56% by weight (Kuraray Co., Ltd., particle-charged nonion, T
g = 0 ° C, tensile strength of film 1.7MPa, elongation at break 1,500
%) 89 g, 10% by weight PVA-420 aqueous solution 10 g, 10% by weight
Glass beads (specific gravity 2.6 average particle diameter 30μ
m) 120g, vermiculite balloon (average particle size 0.5m
m, bulk specific gravity 0.15) 40 g was added and molded from a foamed slurry (apparent density 0.56 g / cm ³ ) in the same manner as in Example 1 to obtain a good foam sheet having a thickness of 5 mm and an apparent density of 0.30 g / cm ³ . . An excellent volumetric shrinkage rate of 11%, a molded sheet having an inorganic content of 70% by weight, and an inorganic volume ratio of 52% were obtained.

Example 4 110 g of methyl methacrylate-butadiene copolymer latex (hereinafter abbreviated as MBR) having a solid content of 45.5% (methyl methacrylate content in the copolymer is about 30% by weight) and alkylbenzene sulphone as an anionic activator. Acid soda 1.0 g
A foamed sheet having a thickness of 5 mm was prepared by the same composition and method as in Example 1 except that This was a sheet having a uniform cell structure, an apparent density of 0.31 g / cm ^{3, and} no cracks and good surface properties. In addition, the apparent volumetric shrinkage during sheet formation
9.1%, total inorganic mass of molded sheet is 69% by weight, volume ratio is 2
4.5%.

Example 5 78 g of SBR having a solid content of 48% by weight, 5 g of a 15% by weight aqueous solution of methylcellulose (0.4% of surface tension 39 mN / m), 30 g of 15% by weight of hydroxyethyl cellulose and 96 of water.
Kaolin powder (100 g) and pearlite balloon (average particle size 0.2 mm, bulk specific gravity 0.38) 40 g were added to the mixed solution of g,
A foamed sheet having a thickness of about 5 mm was obtained in the same manner as in Example 1.
This was a white sheet having a uniform cell structure and an apparent density of 0.35 g / cm ^{3 with} no cracks and good surface properties. The apparent volumetric shrinkage rate during sheet molding was 11%, the total inorganic mass of the molded sheet was 76.6% by weight, and the volumetric rate was 21%.

The cohesive energy densities of the latex of the adhesive and the polymer compound of the emulsion used in Examples 1 to 5 and Comparative Examples 1 and 2 are in the range of 50 to 150 (cal / cc). is there.

[0037]

EFFECTS OF THE INVENTION Since the inorganic light-weight molded product according to the present invention is composed of the above specific composition, it is not only a completely new material, but also processing scraps of inorganic products and waste materials of various inorganic molded products. It can also be used as a raw material in powder form and can be used as a resource by recycling. In addition, since it is possible to obtain a foamed lightweight composition having excellent properties such as light weight and flexibility while maintaining heat resistance and nonflammability, a heat insulating material, a cushioning material, a sound absorbing material, an adsorbing material, a filter material, various laminated composites. It becomes a product that can be widely reused in various industrial fields at low cost as a material for use.

The inorganic lightweight molded product according to the present invention has a porosity of 30 to 80% due to open cells, but since it also uses a hollow balloon, it also possesses closed cells based on the balloon. It has both the characteristics of the inorganic material and the porous organic material. Since the manufacturing method is a wet method and does not use an organic solvent, it is a very safe, simple and inexpensive method.

[Brief description of drawings]

FIG. 1 is a flow chart showing a manufacturing process of an inorganic lightweight molded article of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Imoto 2-6-8 Nakayamadai, Takarazuka-shi, Hyogo

Claims (2)

[Claims] 1. An inorganic compound containing an inorganic balloon having a particle size of 5 to 1,000 μm and a bulk specific gravity of 0.8 or less as one component, a film tensile strength of 10 to 300 MPa, and a surface tension of an aqueous solution of 0.4% by weight at 20 ° C. 30 -65 mN / m, water-soluble polymer compound having two or more hydroxyl groups in one molecule, and water-soluble polymer compound having two or more carboxyl groups or sulfone groups in one molecule and / or anionic Surfactant, film tensile strength 0.1-10MPa, elongation at break 200-2,00
An inorganic lightweight molded product made of a composition of a polymer compound having a second-order transition temperature of −40 to 30 ° C. and a cohesive energy density of 30 to 200 cal / cc. 2. An inorganic compound and a film having a tensile strength of 10 to 300.
A water-soluble polymer compound having a surface tension of 30 to 65 mN / m at a concentration of 0.4 wt% aqueous solution at 20 ° C. of MPa of 0.5 to 10 wt% with respect to an inorganic compound and a water-soluble polymer compound of 1 to 2 is included. 0.5 to 20% by weight of a water-soluble polymer compound having two or more carboxyl groups or sulfone groups in the molecule or / and an anionic surfactant based on the inorganic compound
And the tensile strength of the film is 0.1-10MPa, the elongation at break is 200-2,00
0%, a secondary transfer temperature of −45 to 30 ° C., and a cohesive energy density of 30 to 200 cal / cc, composed of a composition of 5 to 100% by weight with respect to an inorganic compound, and as a component of the inorganic compound. Characterized by adding an inorganic balloon having a particle size of 5 to 1,000 μm and a bulk specific gravity of 0.8 or less so that the total volume ratio of the inorganic material in the molded product is 20% or more and the apparent volumetric shrinkage ratio during molding is 30% or less. An inorganic lightweight molded product having an inorganic compound content of 50% by weight or more and an apparent density of 0.4 g / cm ³ or less.