JPS60141684A - Manufacture of inorganic fibrous elastic foamed body - 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 The present invention relates to a method for producing high quality fibrous elastic foam without the use of asbestos T&fibers.

Kuroiso fibrous elastic foam is generally foamed by adding a suitable binder and surfactant to an aqueous dispersion of acid-free fibers such as asbestos fiber, ceramic fiber, glass fiber, rock wool, carbon fiber, etc. This refers to products produced by molding the resulting aerated foam aqueous dispersion and then drying it. It has 14 degrees of elasticity compared to foamed polyurethane and foamed polyethylene ;), is lightweight, has excellent heat insulation and sound absorption properties, and is also nonflammable.
It can be used as insulation material for high-temperature parts of aircraft, rockets, ships, ponds, and various industrial vessels.

Asbestos fibers are the most suitable as the 1-meter non-fusible fibers used in the production of the non-fusible navy blue elastic foam, as they have excellent properties in terms of dispersibility in water and entanglement. If other fibers are used, the pores of the product tend to be coarse due to poor dispersibility, resulting in a foam with poor elasticity.

However, in recent years, it has become difficult to use asbestos # & Mk 1φ due to environmental hygiene reasons, so even if you do not want to use asbestos fibers, it is difficult to use asbestos fibers. φ"
Various ideas have been proposed to address the need to produce individual foams. One of the representative methods is the method described in Japanese Patent Publication No. 57-6O32O, which uses swellable synthetic heptadonite mica that is swellable in water as an auxiliary raw material. Swelling Synthesis 7) Elementary mica swells in water and has the property of folding into ultrafine particles with the slightest force. Based on its unique colloidal chemical properties, mica helps disperse and entangle fibers, and also stabilizes air bubbles. It is an excellent auxiliary agent when producing elastic foams.

Although swellable synthetic heptagonal mica is effective as shown in "Double", its drawback is that even when an effective amount of it is added, an aqueous dispersion of cellular inorganic fibers may exhibit a strong thixotropic phenomenon.

For this reason, if the aqueous dispersion is left standing in a storage tank after preparation, it will rapidly lose its fluidity, or it will become difficult to cast the mold. Therefore, to ensure fluidity for 1 minute, stirring must be continued up to the molding surface, but this not only requires a stirring device in the storage tank, but also causes excessive stirring (for reasons other than fluidity). This may also lead to denaturation of the slurry (at points). In this IJ, the bubbles are sufficiently fine in the aqueous dispersion state, but the bubble diameter tends to grow during the drying process after molding, which also has the disadvantage that the elastic recovery power of the product is rather poor.

Furthermore, swellable synthetic fluorinated mica swells when it absorbs water in the final product, reducing the strength of the product (because of the
Its use in producing foams for applications requiring water resistance has been problematic.

The purpose of this invention is to solve the drawbacks of the method of manufacturing an inorganic elastic foam using a single layer of swellable synthetic fluorinated mica as described above.

Having succeeded in achieving the above object, the present invention provides one or more viscosity modifiers, amphoteric surfactants selected from the group consisting of polyethylene oxide, methylcellulose, carboxydimethylcellulose and polyvinyl alcohol.
and magnesilla oxide or hydroxide to prepare an aerated aqueous dispersion of inorganic fibers and swellable synthetic fluorinated mica, which is then molded, dried and fired, and then treated with methyltriethoxysilane. It is characterized by this.

Viscosity modifiers such as polyethylene oxide, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, etc., when added in appropriate amounts, can cause swelling properties such as 7
It has the effect of alleviating the thixotropy of the mica fine particle dispersion, improving the dispersion of fibers, and smoothing the flow of the entire dispersion during casting. Among them, polyethylene oxide with a molecular weight of 100,000 or more is particularly excellent in the above-mentioned effects.The preferable addition rate of ν1 is 0 to the total amount of undefeated fibers and swellable synthetic fluorine mica.
．． It is 3-5%. Using an excess amount will significantly increase the viscosity of the slurry and make stirring difficult.

The amphoteric surfactant not only generates fine and stable bubbles in the dispersion containing the swellable synthetic 7-nine mica and the above viscosity modifier, but also helps in forming and drying the dispersion during each step. Its ability to keep the bubble size stable is significantly better than that of other surfactants. Among the amphoteric surfactants, those having the amidobetaine type, for example those having the structural formula (%), exhibit particularly excellent performance, and are therefore the most preferred surfactants for use in the present invention. The appropriate addition rate is 5 to 10% based on the total solid content.

In addition, magnesium oxide or hydroxide is used to enhance the effect of silane treatment, which is applied after molding, and the appropriate amount is 5 to 20% of the total solid content.
Preferably E is ~15%.

The manufacturing method of the present invention using an Ri degree adjusting agent and an amphoteric surfactant: The appropriate addition rate of swellable synthetic heptadonite mica is 30 to 15% for one month of inorganic fibers. .

In the production method I of the present invention, the method for preparing the aerated aqueous dispersion of inorganic fibers containing the above-mentioned raw materials is not particularly limited. A particularly desirable method for fully demonstrating this is as follows. First, only the inorganic fibers are added to water containing a viscosity modifier and stirred vigorously to disperse the i-kon blue. The obtained filament dispersion was mixed with a separately prepared swelling compound II.
! , fluorine mica water molecules af1. Then, the amphoteric surfactant and the oxide or hydroxide of magnesium are added and stirred vigorously to perform the 7-step process. The operation of adding a surfactant and foaming may be performed in advance on the swellable synthetic fluorine cloud 1u dispersion.

To mold the aqueous foam-containing dispersion of inorganic fibers, it is poured into a wall frame and immediately dried with hot air at about 10 ri to 350°C. As the heating means, it is also possible to employ infrared heating, high frequency heating, etc. After drying, about 10 more
Heat to 0°C and bake to remove any impurities.

After firing, the molded body is then treated with methylated N-disilane. The method is not limited to 1 h, but the most advantageous method is in a closed room, preferably for about 1 h.
, 4.0~] 8 (',) 'C is brought into contact with the combined force of water vapor and gaseous methyltriethoxysilane. 1
It is desirable to do this to an extent that ~3% of methyltriethoxysilane is consumed, thereby improving the water resistance without worsening the water resistance of the foam. It should be noted that the treatment of asbestos foam with methyltriethoxysilane to improve its waterproof properties was disclosed in Japanese Patent Publication No. 57-17.
Although it is described in Japanese Patent No. 879, in the case of asbestos-free, swellable synthetic 7N 1U-containing rock-free fibrous foam, the treatment effect is not significant in any form if the method is used as is. The effect of improving water resistance becomes noticeable only by adding magnesium oxide or hydroxide. Although its mechanism of action is not clear, it is probably due to the reaction between methylnidoxin or the hydroxyl group of the magnesium compound to form a siloquine bond.

The hollow elastic foamed wood obtained by the production method of the present invention, as described above, contains the above-mentioned swellable synthetic fluorine head, viscosity modifier, amphoteric surfactant and magnesium oxide. Or, due to the action of hydroxide, even when using fibers other than asbestos fibers, such as ceramic fibers, glass navy blue, rock wool, carbon fibers, etc., the air bubbles are finely and evenly distributed, and asbestos It has good elasticity comparable to fiber-based products.It also has the advantage of less deterioration of physical properties even when used in a high humidity atmosphere or in contact with water.According to the present invention, it has excellent elasticity. An inorganic elastic foam having these properties can be easily produced with a high degree of quality stability.

The present invention will be explained below with reference to Examples.

Example 1 Add 20 g of Swelling Synthesis 7 [Mica L] M Clean (product of Topy Industries, Ltd.) to 300 g of water and stir for about 30 minutes. Separately polyethylene oil/alco/las 1r)
o OR (Kusei Kagaku Kogyo Co., Ltd. product; molecular weight 101-50
Prepare 200+nl of a 2% aqueous solution of
0g and 17.5g of magnesium hydroxide,
Stir with a stirrer at 000 rlun for about 20 minutes to disperse the fibers. The obtained fiber dispersion was added to the Erjiyun No. 1 dispersion, and then a 10% aqueous solution of a midobetaine type amphoteric surfactant, Lebon 200 (product of Sanyo Chemical Industries, Ltd.)
Add h+l and 7 t) ml of water. After this, l 00
0-15 f:l f) Stir with rlon stirrer,
Whisk until the total volume is 2000ml. The obtained bubble-containing dispersion was heated to 30 t) InmX 3 (l
t) Pour into a punched metal box measuring h+mX 30 blll and dry at 100°C for 12 hours.

Then, the foamed wood was fired in an electric furnace at 10'C for 30 minutes, the resulting foamed wood was transferred to a closed room at 160°C, and the space in the room was filled with steam, and then 10% methyl based on the weight of the foam was added. Triethoxysilane was introduced and vaporized.60
After a few minutes, the heating was stopped and air was blown in for 30 minutes to drive out the ethanol formed, and the treated foam was removed.

The characteristics of the air-containing foam fiber dispersion liquid and the quality of the product were investigated for Examples of the present invention as shown in J2 above, and for Gessho Example A which was the same as above except that no magnesium hydroxide was added. The results are shown in Table 1.

Example 2 Add 60g of swellable synthetic heptadonite mica to 1g of water and stir for 30 minutes, then add 2f)g' of bentonite (Hojun Yoko product) and mix 1().
Stir for a minute. Furthermore, 3 (10 ml) of water and 1 (]% solution of amide betaine type amphoteric surfactant Levon 105)
Add 50 ml, 10 (,lt) −] 500
Stirring at rp+n (how many times do you stir, the total volume is 8000
Whisk until the volume reaches ml. Separately, polyethylene oxide Alfugges E-30 (molecular weight 100,000 to 5 ()
A fiber dispersion liquid was prepared by dispersing 95 g of silica alumina fiber Fine Flex and 3.2 g of magnesium oxide in 1000 ml of a 1.2% solution of The slurry is then processed in the same manner as in Example 1 to obtain an inorganic fiber navy blue elastic foam book.

Regarding the examples of the present invention as described above, the characteristics of the air-containing T & navy blue dispersion and the quality of the product were investigated. The results are shown in Table 1.

Claims (2)

[Claims] (1) Inorganic fibers are produced by adding one or more viscosity modifiers selected from the group consisting of polyethylene oxide, methyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol, an amphoteric surfactant, and magnesium oxide or hydroxide. and an air-containing aqueous dispersion of swellable synthetic heptagonal mica, which is molded, dried and fired, and then treated with methyltriethoxysilane. Book manufacturing method. (2) The manufacturing method according to claim 1, wherein 5 to 2% of magnesium oxide or hydroxide is used based on the total solid weight.