JP2003225529A - Method for reutilizing glass fiber waste material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reutilizing a glass fiber waste material by imparting a humidity conditioning function hereto, and to obtain a humidity conditioning material utilizing glass fibers. <P>SOLUTION: A glass fiber material or the glass fiber waste material and an alkali metal hydroxide aqueous solution with a concentration of 10-50 wt.% are heated and dried at 80-250°C to obtain the humidity conditioning material with a humidity absorbing and discharging ratio of 5 wt.% or more. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling glass fiber waste materials that have been discarded after being used as heat insulating materials, FRP, and the like. The present invention relates to a humidity control material suitable as a humidity control material, a humidity control heat insulating material, and the like.

[0002]

2. Description of the Related Art Glass fibers are widely used as heat insulating materials for general houses and buildings, sound absorbing materials and FRP reinforcing materials.
A large amount of removed glass fiber waste material is generated during the inspection, repair and dismantling of buildings and equipment. This waste material is landfilled as industrial waste. Landfill disposal requires a vast area, but in recent years it has become difficult to secure land, which is a major social problem.

The waste glass fiber material has its surface covered with a resin film or moisture-proof paper, has a phenol resin binder for adhering the fibers adhered thereto, and has a large amount of binder resin in FRP. , Its processing is difficult. Therefore, the present situation is that effective recycling of waste glass fiber materials has not been carried out.

By the way, in recent years, there has been a problem of dew condensation in a living space such as a concrete structure, and various moisture absorbing / releasing materials have been proposed to prevent it. For example, Patent 3026604 is a material using gypsum board, Patent 3
No. 065607 discloses a material utilizing calcium silicate.
Patents 2948133 and 3041348 use natural minerals,
A material whose specific surface area is specified is disclosed. In addition, special fair 6-
49131 and JP-A-10-266366 describe inorganic foams and SiO _2-.
Disclosed is a material obtained by using an Al ₂ O ₃ powder or the like as an alkali metal silicate, so-called water glass, as a binder.
Furthermore, the applicant of the present invention has also filed JP-A-9-328374 and JP-A-11-322.
No. 468 and the like disclose materials obtained by alkali-curing pearlite and the like.

Further, Japanese Patent Application Laid-Open No. 9-124315 discloses a hardened zeolite body in which silica-alumina powder particles such as rock wool are treated with alkali, dehydrated, pressure-molded and then hydrothermally treated. Furthermore, JP-A-6-183813 discloses rock wool and the like.
Disclosed is a molded product obtained by hot press molding in the presence of water together with an alkali stimulant such as wood chips. It provides high strength materials such as alternatives to concrete products.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the above-mentioned conventional problems and to provide a method for reusing a waste glass fiber material by imparting a new function, particularly a humidity control function, and a glass fiber. To provide a humidity control material.

[0007]

That is, according to the present invention, a waste glass fiber material and an aqueous alkali metal hydroxide solution having a concentration of 10 to 50% by weight are heated and dried at 100 to 220 ° C. to obtain a moisture absorption and desorption rate of 5% by weight. It is a method of reusing a waste glass fiber material, which is characterized in that the above humidity control material is obtained. The glass fiber waste material may be mixed with silica such as pearlite, diatomaceous earth, and clay and / or aluminum hydroxide. Further, the present invention is characterized in that it is obtained by heating and drying glass fiber and an aqueous alkali metal hydroxide solution having a concentration of 10 to 50% by weight at 80 to 220 ° C. and a moisture absorption and desorption rate of 5% by weight or more. It is a humidity control material.

The present invention will be described in detail below. The glass fiber referred to in the present invention means so-called heat insulating material, sound absorbing material, FRP.
In addition to glass fibers used for the above, etc., it includes scraps and the like generated in the processing steps of these products, and unused glass fibers. Since most of this waste glass fiber material is relatively large, it is first coarsely crushed to select the glass fiber. It is desirable to remove the resin film and the moisture-proof paper covering the surface of the glass fiber heat insulating material. For FRP, it is desirable to remove the binder resin. The mixture mainly composed of glass fibers thus obtained may be used as it is,
It is also possible to crush and use it in the form of powder.
Due to the reaction with the alkali metal hydroxide, it is easier to obtain the humidity control performance, which is the effect of the present invention, by using a more pulverized product.

Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide and lithium hydroxide, but it is preferable to use inexpensive sodium hydroxide or potassium hydroxide from the viewpoint of cost efficiency. The present invention uses this alkali metal hydroxide as an aqueous solution, but the concentration of the alkali metal hydroxide is 10 to 50% by weight,
It is preferably 15 to 45% by weight. This is 10% by weight
If it is lower, the reaction between the glass fiber and the alkali metal hydroxide does not proceed, and only one having low humidity control performance is obtained, and it takes time to heat and dry to drive off excess water. If the concentration exceeds 50% by weight, the aqueous solution will be difficult to disperse throughout the material.

The amount of alkali metal hydroxide added varies depending on the degree of pulverization of the waste glass fiber material and the content of silica contained in the glass fiber. If the powder is crushed to the extent of passing through a 150 mesh screen, silica 1 in glass fiber
In the case of sodium hydroxide, it is preferable to add 3 to 25 parts by weight, preferably 5 to 15 parts by weight, as solid content, relative to 00 parts by weight. If this amount is less than 3 parts by weight, sufficient moisture absorption and desorption properties cannot be obtained, and if it exceeds 25 parts by weight, excess sodium hydroxide remains and the product exhibits deliquescent properties, which is not practical.

It is considered that the alkali metal hydroxide reacts with the silica of the glass fiber to generate alkali silicate, which undergoes polycondensation gelation in the dehydration process to form an active surface which absorbs and releases moisture in the air. In order to supplement this function, silica such as perlite, diatomaceous earth, and clay, or aluminum hydroxide may be added to the glass fiber mixture. Silicas are considered to form alkali silicate as in the case of glass fiber, and when aluminum hydroxide is added, the strength of the product can be increased. It is preferable to add 5 to 25 parts by weight of silica and 2 to 10 parts by weight of aluminum hydroxide.

The glass fiber and the alkali metal hydroxide aqueous solution are sufficiently mixed in a state of containing appropriate water to prepare a wet mixture, and the wet mixture is heated at 80 to 220 ° C, preferably 100 to 200 ° C. dry. This is one in which water is forcibly removed at the same time as the reaction, and the standard is 3 to 10 minutes when the mixture is granular and 5 to 15 minutes when it is a granulated product of about 10 mm. The heating and drying conditions vary depending on the amount and shape of the feed material and the capacity of the heating device. If the temperature is lower than 80 ° C., the drying is slow, the reaction does not proceed sufficiently, and a humidity control material having a moisture absorption and desorption rate of 5% by weight or more specified in the present invention cannot be obtained. Further, even if the heating temperature is further increased, the moisture absorbing / releasing performance is not improved and the economical efficiency is impaired.

The moisture absorption and desorption rate specified in the present invention is 25 ° C., 9
By repeating 0% environment and 25 ° C, 50% environment every 24 hours, the difference in weight between the weight when absorbing moisture and the weight when releasing moisture is almost constant is divided by the dry weight. is there.

The humidity control material of the present invention is in the form of powder, depending on the application.
It can be processed into any shape such as spherical shape, rod shape, plate shape, and flake. In this processing, the wet mixture before heating and drying may be granulated and pressure-molded, or after heating and drying, granulation and pressure-molding may be performed. It is also possible to put them in a breathable bag for easy handling. Applications of the humidity control material of the present invention include under-floor humidity control materials, indentation humidity control materials, humidity control heat insulating materials and the like.

[0015]

EXAMPLES Examples 1-3, Comparative Examples 1-2 Discarded glass fiber heat insulating material was crushed with a ball mill and
A pulverized product A that passed through a 50-mesh sieve was obtained. Further, the discarded FRP pipe was roughly crushed and the glass fiber was selected to obtain a crushed product B having a fiber length of several mm. An aqueous sodium hydroxide solution was added to these pulverized products, and the mixture was sufficiently stirred and dried by heating to obtain a humidity control material. In Example 2 and Comparative Example 2, diatomaceous earth powder was further blended, and in Example 3, clay powder and aluminum hydroxide were further blended. Table 1 shows the material composition (sodium hydroxide aqueous solution concentration is wt%), the heating and drying conditions, and the moisture absorption and desorption rate (wt%) of the humidity control material. Numbers without unit are parts by weight.

[0016]

[Table 1]

[0017]

EFFECTS OF THE INVENTION According to the present invention, a waste material containing glass fiber, which has been conventionally discarded, can be given a function of reacting an alkali metal hydroxide to absorb and release moisture in the air. It has become possible to reuse it as a humidity control material.
It also opened up new uses for glass fibers.

Claims (4)

[Claims] 1. A glass fiber waste material and an alkali metal hydroxide aqueous solution having a concentration of 10 to 50% by weight are heated and dried at 80 to 220 ° C. to obtain a humidity control material having a moisture absorption and desorption rate of 5% by weight or more. Reuse method of waste glass fiber materials. 2. The method for recycling a waste glass fiber material according to claim 1, wherein the waste glass fiber material is blended with silica such as pearlite, diatomaceous earth, and clay and / or aluminum hydroxide. 3. A humidity control material obtained by the method for recycling a waste glass fiber material according to claim 1 or 2. 4. A glass fiber and an alkali metal hydroxide aqueous solution having a concentration of 10 to 50% by weight are heated and dried at 80 to 220 ° C. and have a moisture absorption and desorption rate of 5% by weight or more. Humidity control material.