JPS6319461B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing reinforced inorganic foam granules. Inorganic foam granules such as perlite, vermiculite, and shirasu balloons are extremely porous and ultralight, so they have excellent properties such as heat insulation, nonflammability, sound absorption, water retention, and light weight. The major drawback is that the compressive strength of individual particles is extremely low. Therefore, its use as a heat insulating material is also severely limited. The present inventor has conducted extensive research into improving the strength, which is a drawback, while maintaining the original excellent properties of the above-mentioned inorganic foam granules, and by perfecting these properties, the inorganic foam granules can be improved. The present invention was completed as a result of research into making it a versatile material as a heat insulating material. That is, the present invention comprises an aqueous liquid containing 0.1 to 10% by weight of an organic or inorganic aqueous binder;
The weight ratio of water in the aqueous liquid to cement is 0.5~
This method of producing inorganic foam particles coated with cement is characterized by mixing cement in an amount of 2.0 to form a paste, and kneading the paste and inorganic foam particles. The present invention will be explained in detail below. Generally, the hydration reaction between water and cement is very slow and takes several to several tens of days. When coating inorganic foam granules with cement, the water absorbed in the inorganic foam granules gradually undergoes a hydration reaction with the cement coated on the outer shell, gradually forming a stronger cement-covered shell. do. At the early stage of the hydration reaction, the cement in the outer shell has not yet reacted with the water in the inorganic foam particles, and the cement shell is very weak and easily peels off. Therefore, if any external force is applied by handling or other means from the initial stage of the hydration reaction until the reaction is almost completed, the cement coating will peel off and the purpose cannot be achieved. The presence of an organic or inorganic binder here fixes the cement shell to the outer shell of the inorganic foam granules and prevents it from peeling off even when external force is applied. Therefore, it is necessary for the organic or inorganic binder to exist until the hydration reaction of the cement is completed and the cement shell solidifies with the outer shell of the inorganic foam granules. There is no problem even if it burns out or changes in quality when exposed to high temperatures during the subsequent drying process. The organic or inorganic binder used in the present invention may be any binder as long as it can be mixed into cement together with water for the above reasons, and in general, water-soluble binders are preferred, but binders that are emulsified in water may be used. There is no problem even if there is. For example, water glass as a water-soluble binder,
There are polyvinyl alcohol and acrylic resin, and those used in an emulsified state in water include vinyl acetate resin, asphalt, and synthetic rubber. (Hereinafter, the binder used in an emulsified state in water and the water-soluble binder may be collectively referred to as the aqueous binder, and the liquid may be abbreviated as the aqueous liquid). The concentration of the above binder in water is determined based on the relationship with the amount of water suitable for the hydration reaction of the cement used.
The amount of binder is preferably 0.1 to 10% by weight, and less than 0.1% by weight is not preferable because the amount of binder is less than the amount necessary to bind cement to the inorganic foam granules. The aqueous binder liquid and cement are mixed in such a manner that the weight ratio of water/cement in the aqueous liquid is 0.5 to 2.0. In the case of ordinary Portland cement, the ratio of water/cement is most preferably 1.0, but the ratio is appropriately selected within the above range depending on the type of cement. To make a paste by mixing an aqueous binder liquid and cement, the aqueous binder liquid may be prepared first, and then cement may be mixed with this aqueous liquid, or the three components, water, binder, and cement may be mixed at the same time. do not have. The inorganic foamed particles used in the present invention are not particularly limited as long as they are lightweight porous inorganic particles such as pearlite, vermiculite, shirasu balloons, artificial lightweight aggregates, and blast furnace slag, but among them, pearlite is Common. The amount of cement paste consisting of binder aqueous liquid and cement is used per 1 m ³ of inorganic foam granules.
120 to 300 kg is preferred, and 180 to 230 kg is particularly preferred. If it is less than 1120 kg, the amount of cement to be coated is small and the amount of binder is also insufficient, so that the strength of the inorganic foam granules does not improve. On the other hand, if it exceeds 300 kg, the amount of cement increases, which impairs the lightweight properties of the inorganic foam granules, and the degree of improvement in strength is small compared to the amount of cement, and the heat insulating material is deteriorated, which is not preferable. To knead the cement paste and the inorganic foamed granules, the paste and the inorganic foamed granules may be put into a suitable kneading device and mixed. may be added at the same time. Although a concrete mixer or the like can be used as a suitable kneading device, a pack mill is preferred. These kneading devices can uniformly coat the surface of the inorganic foam granules with cement, and in particular, a pack mill allows continuous kneading and mass production. The cement-coated inorganic foam granules thus obtained, after a curing period of at least 3 to 10 days,
It is manufactured into a product through a drying process using a drying temperature of ℃ or higher. Next, the present invention will be explained in more detail with reference to Examples. Example: 100% water was heated to 90±5% by electric heater in an aquarium.
℃, add 7.5 kg of polyvinyl alcohol as a binder, and stir well to dissolve completely. This polyvinyl alcohol aqueous solution 100%
Then, 100 kg of cement and 1 m ³ of obsidian-based pearlite as inorganic foam granules were put into a pack mill.
At this time, the feeding speed is 10% of the polyvinyl alcohol aqueous solution.
/min, cement 10Kg/min, perlite 100
/min. Knead for several minutes in a powder mill to obtain cement-coated pearlite. This material was left stationary in a tank for 7 days for air curing. Once curing is complete, leave it in hot air at 150℃ for about 10 minutes to dry it and use it as the final product. The strength of the products of the present invention and, for comparison, pearlite coated with cement paste to which no binder was added and unprocessed raw pearlite were examined. The strength can be determined by filling a pressure test container with an inner diameter of 50 mm and a height of 135 mm, and using a diagram showing the relationship between the magnitude of stress applied from above and the length of subsidence at the top level of the pearlite layer. It is shown in the table below along with other quality characteristics.

【table】

【table】 [Brief explanation of the drawing]

The figure is a graph showing the relationship between the magnitude of stress and the length of settlement.

Claims (1)

[Claims] 1. 0.1 to 10 organic or inorganic aqueous binder
Mixing an aqueous liquid containing % by weight and cement in an amount such that the weight ratio of water in the aqueous liquid to cement is 0.5 to 2.0 to form a paste, and kneading the paste and inorganic foam particles. A method for producing inorganic foam particles coated with cement, characterized by: 2. The manufacturing method according to claim 1, wherein the organic or inorganic binder is water glass, polyvinyl alcohol, acrylic resin, vinyl acetate resin, or synthetic rubber. 3. The manufacturing method according to claim 1, wherein the inorganic foam particles are pearlite, vermiculite, shirasu balloon, artificial lightweight aggregate, or blast furnace slag slag. 4 The paste used for kneading is 1 m ³ of inorganic foam particles.
The manufacturing method according to claim 1, wherein the weight is 120 to 300 kg.