JPS627681A - Manufacture of inorganic heat insulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a nonflammable inorganic heat insulating material used for walls and roofs of buildings such as houses, buildings, and warehouses for freezing and refrigerated storage. .

[Conventional technology] With the improvement of living standards, heating and cooling of houses and buildings has become popular.
In addition, as freezers and refrigerated warehouses have become larger, there has been a demand for the development of insulation materials with excellent heat insulation properties, and for a time organic materials have come to be used. However, such organic heat insulating materials have problems from the viewpoint of disaster prevention, such as flammability, smoke-emitting properties, and harmful gas-emitting properties, and their use is gradually being restricted.

Therefore, in order to solve these problems such as flammability, smoke generation, and harmful gas generation, we have developed a granular inorganic foam with an inorganic binder such as portland cement or alkali silicate as an insulating material that can be used safely from a disaster prevention perspective. An inorganic heat insulating material has been proposed, which is obtained by adding and bond-molding this inorganic foam.

[Problems to be Solved by the Invention] However, if Portland cement is used as an inorganic binder for bonding inorganic foam, it has the advantage of increasing its compressive strength, but There is a problem that the weight of the material increases and the weight reduction is impaired, and using an alkaline silicate binder does not cause any problem in terms of making the material lighter, but it is insufficient in terms of compressive strength, water resistance, and weather resistance. There was a problem that.

[Means for Solving the Problems] The present invention was devised in view of this point of view, and takes advantage of the lightweight feature of the alkali silicate binder, improves compressive strength and water resistance, and improves hardening. The purpose of the present invention is to provide a method for manufacturing an inorganic heat insulating material that can shorten the time required for manufacturing and improve productivity.

That is, in the present invention, when producing an inorganic heat insulating material by mixing an alkali silicate solution as a binder with a granular inorganic foam and reinforcing additives blended as necessary, and bonding and molding the mixture, the curing agent for the binder is used. This is a method for producing an inorganic heat insulating material using a combination of metal silicon powder and phosphate.

The granular inorganic foam used in the present invention includes:
It may be any conventionally known material, but is preferably obsidian, vermiculite, nacre, or pinestone. These inorganic foams can be used alone or as a mixture of two or more. can also be used. The particle size and density of this inorganic foam vary depending on the type of product insulation material and its intended use, but are usually 0.5 to 7.
A particle size of M and a density of usually 0.1 to 0.25 g/cIn3 are used. In addition, especially when lightweight and excellent heat insulation properties are required, the density is 0.1 to 0.16 g/α.
It is preferable to use No. 3.

Further, as the alkaline silicate solution used as a binder in the present invention, a sodium silicate aqueous solution or a potassium silicate aqueous solution is usually used, but a sodium silicate aqueous solution is preferably used from the viewpoint of solubility in water and raw material cost. As for sodium silicate, the molar ratio of SiO and Na2O is usually 2.0 to 3.5, preferably 2.3 to 2.
7, and the concentration of its aqueous solution is usually 35 to 42% by weight, preferably 40 to 42% by weight. The amount of the alkaline silicate solution to be used varies depending on its concentration, but it is usually 30 to 120 parts by weight, and 50 to 100 parts by weight for a good mold, based on 100 parts by weight of the inorganic foam. If the amount of the alkaline silicate solution used is less than 30 parts by weight, the bonding force will be small, resulting in a decrease in strength, while if it is more than 120 parts by weight, the binder will be excessive.
This results in the binder component flowing out during the exothermic/dehydration curing reaction stage, resulting in the problem that it does not work effectively. Note that the alkali silicate used in the present invention is not limited to alkali silicate as a single substance, but also includes so-called water glass obtained by heating and melting silicon dioxide and alkali hydroxide, such as sodium metasilicate, A mixture of sodium orthosilicate, sodium disilicate, sodium tetrasilicate, etc. may be used.

The metal silicon powder, which is one component of the curing agent used in the present invention, is not limited to metal silicon itself, but also includes those that have properties as metal silicon, for example,
Ferrosilicon, which is an alloy of iron and silicon, and a mixture of metallic silicon and silicon dioxide can also be used.

This metal silicon powder produces silicic acid (Si02) through the following reaction with, for example, sodium silicate, and gradually becomes SiO/Na.
Sodium silicate with a high molar ratio of 2O is formed.

Na O-8to2+l-120,'NaOH+Na
H8i 03 NaH8i 03+H20-p Na OH+ H2S i O3 Si +2NaOH+nH2O→ Na SiO+2H2↑ The amount of this metal silicon powder used varies depending on the type and concentration of the alkaline silicate solution, but the amount of alkaline silicate solution 100
Usually 10 to 20 parts by weight, preferably 1 part by weight
Type needles at 3 to 15 fingers. If the amount of metal silicon powder used is less than 10 parts by weight, the compressive strength and water resistance will be insufficiently improved, and if it is more than 20 parts by weight, the metal silicon powder will be oxidized and will not work effectively.

The phosphate to be used as another component of the curing agent may be one that reacts with an alkali silicate during the curing reaction to produce a binder substance that is poorly soluble in water and has excellent thermal stability. are metal phosphates such as aluminum phosphate, magnesium phosphate, iron phosphate, zinc phosphate, metal salts of polyphosphoric acid, and condensed phosphorus in which metal oxides and phosphorus pentoxide are combined in a predetermined ratio. There are acid metal salts, etc., and condensed metal phosphates typified by condensed aluminum phosphate are more preferred. The amount of this phosphate to be used is determined by the amount of alkali in the alkaline silicate solution, and varies depending on the type and concentration of the alkaline silicate solution, but is usually 2 to 30 parts by weight per 100 parts by weight of the alkaline silicate solution. Preferably, it has 10 to 20 convex portions. If the amount of phosphate used is less than 2 parts by weight, the improvement in compressive strength and water resistance will be insufficient, and if it is more than 30 parts by weight, no improvement in the improvement effect on compressive strength or water resistance will be observed. .

In the present invention, a conventionally known method can be adopted as a molding method when manufacturing the inorganic heat insulating material. For example, the inorganic foam is mixed with metal silicon powder and phosphate as a hardening agent. Next, an alkaline silicate solution as a binder is added to this mixture, mixed, poured into a mold of a desired shape, and left to stand at room temperature to harden. After the exothermic/dehydration curing reaction is completed, it is removed from the mold and left to dry.

For example, when forming a board, the formwork to be used is
A frame plate with gas vent holes on at least one side is provided, and the mixture is injected and filled while giving a motion to ensure uniformity, and when filling is completed, gas vent holes are provided to prevent ejection during exothermic reaction. Cover, tighten and leave. When left at room temperature for about 30 minutes, what initially reacted gradually becomes a hardening reaction of dehydration condensation accompanied by rapid heat generation and evaporation of water vapor. After this curing reaction is completed, it is removed from the mold and left to dry.

In the present invention, examples of reinforcing additives that may be blended as necessary include mineral fibers such as steel fibers, glass fibers, and rock wool. It can be selected as appropriate depending on the usage etc. In addition, when this reinforcing additive is blended, the amount of the alkali silicate solution and curing agent to be used will vary depending on the type of reinforcing additive, considering this reinforcing additive as a part of the inorganic foam. , requires a slight increase in volume.

[Function] In the present invention, metal silicon powder and phosphate are used together as a hardening agent, so when this hardening agent comes into contact with an alkaline silicate solution as a binder and hardens it, it is violently oxidized by the oxidation of the metal silicon. It is thought that an exothermic dehydration condensation reaction occurs, and that the phosphate rapidly undergoes a condensation reaction with the activated sodium silicate at the same time as this exothermic reaction, resulting in polymerization. As a result, the amount of silicon oxide in the cured product is increased, and it is thought that the phosphate efficiently cures the alkali silicate to form a stable cured product.

[Example] Hereinafter, the method of the present invention will be specifically explained based on Examples and Comparative Examples.

Example: Inorganic foam with average particle size of about 11M and density of 0°12g.
/α3 obsidian foam 120g is used, and 40%
100g of sodium silicate aqueous solution and 25g of ferrosilicon
and a curing agent consisting of condensed aluminum phosphate (for example, Hoechst product name: HB Hardener) O to 309, and mixed to form 200a+X 200s+X 20m.
The mixture was poured into a mold for forming a board material, left at room temperature for about 30 minutes to heat-cure, then removed from the mold, and left to dry for 24 hours to form an inorganic foam board. A test piece (40 m x 40 m x 20 #l) was cut out from this foam board.

The obtained test piece was soaked for 24 hours and soaked for 15 hours.
A thermal boiling treatment was carried out for a minute, and the compressive strength was measured before and after immersion, and the relationship between the amount of condensed aluminum phosphate added to 100 g of a sodium silicate aqueous solution and the compressive strength was determined. The results are shown in Figure 1. The compressive strength was determined by applying pressure to the test piece from the surface direction and determining the pressure value when the test piece began to collapse.

Comparative Examples 1 and 2 Comparative Example 1 is a case in which only ferrosilicon is used as a curing agent, and Comparative Example 2 is a case in which only the above condensed aluminum phosphate is used as a curing agent. Test pieces were molded in the same manner as in the above Example except that Comparative Example 2 was cured with heat at room temperature for 168 hours.
The relationship between the amount of ferrosilicon added to the sample and compressive strength (Comparative Example 1) and the relationship between the amount of condensed aluminum phosphate added to 100 g of sodium silicate aqueous solution and compressive strength (Comparative Example 2) were determined. The results are shown in FIGS. 2 and 3.

[Effects of the Invention] According to the present invention, since metal silicon powder and phosphate are used together as a hardening agent, the inorganic heat insulating material of the product is improved compared to the case where these metal silicon powder or phosphate are used alone. Compressive strength and water resistance are significantly improved. In addition, because an exothermic and dehydrating reaction occurs and is chemically activated, the curing time of the binder during molding can be significantly shortened.
Its productivity can be improved.

[Brief explanation of drawings]

Fig. 1 is a graph showing the relationship between the amount of curing agent added and compressive strength in the test piece according to the example of the present invention, and Fig. 2 is a graph showing the relationship between the amount of curing agent added and compressive strength in the test piece according to Comparative Example 1 A graph showing the relationship. FIG. 3 is a graph showing the relationship between the amount of curing agent added and the compressive strength in the test piece according to Comparative Example 2. Patent applicant Nippon Light Metal Co., Ltd. Representative Patent attorney Tomohiro Nakamura (2 others)

Claims (5)

[Claims] (1) When manufacturing an inorganic heat insulating material by mixing an alkali silicate solution as a binder with a granular inorganic foam and reinforcing additives blended as necessary, and bonding and molding the mixture,
A method for producing an inorganic heat insulating material, characterized in that a metal silicon powder and a phosphate are used together as a hardening agent for the binder. (2) The method for producing an inorganic heat insulating material according to claim 1, wherein the inorganic foam is one or a mixture of two or more selected from the group consisting of obsidian, vermiculite, perlite, and pinestone. (3) The method for producing an inorganic heat insulating material according to claim 1 or 2, wherein the alkaline silicate solution is a sodium silicate solution. (4) The method for producing an inorganic heat insulating material according to any one of claims 1 to 3, wherein the phosphate is a condensed phosphate. (5) Production of the inorganic heat insulating material according to any one of claims 1 to 4, wherein the blending ratio of phosphate in the binder is 2 to 30 parts by weight per 100 parts by weight of the alkaline silicate solution. Law.