JP2001329629A - Heat-insulating coating granule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-insulating coating granule as a flame-retardant or incombustible heat-insulating material, by which heat-insulating execution works are facilitated, and light-weight aggregate having excellent dispersibility in case of the mixing of cement. SOLUTION: The granular heat-insulating coating granules used as the flame- retardant heat-insulating material, which allows wind to blow into an opening or the like of a house, and the light-weight aggregate having excellent dispensability are manufactured by applying a coating composed of an inorganic substance to the foam grains of a synthetic resin. The granular heat-insulating coating granules used as the flame-retardant heat-insulating material, which is applied easily to a ceiling or the like for the house, is manufactured by granulating the foam grains of the synthetic resin in a granulated powder shape by a binder. The incombustible heat-insulating coating granules used as the porous heat-insulating material having moisture absorbing-desorbing properties are manufactured by destroying the foam grains of the synthetic resin by fire by furning the granular heat-insulating covering substances.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating coated particle used as a heat-insulating material for ceilings, walls, floors and the like in houses and the like. The present invention relates to a heat-insulating coated particle which is suitable for construction and also suitable as a lightweight aggregate such as cement.

[0002]

2. Description of the Related Art Conventionally, glass wool and flame-retarded cellulose fibers have been known as heat insulating materials used for insulation of ceilings and outer walls of houses by a blowing method. These short fiber materials, such as glass wool, belong to an insulating material called open-cell type, where the fibers subdivide the space, confine air, prevent heat transfer by convection, and perform their function. It is used as a lightweight, non-combustible or flame-retardant heat insulating material. On the other hand, foamed particles of a synthetic resin are known as a lightweight and heat-insulating material similar to glass wool or the like. Above all,
Expanded polystyrene particles belonging to a heat insulating material called a closed-cell type have small air convection and more excellent heat insulating properties because bubbles in a foam are independently present by partition walls. These foam particles are mainly used as lightweight aggregates for concrete and mortar.

[0003]

However, glass wool or cellulose fiber for blowing has poor fluidity, especially when filling in voids in existing houses during heat insulation construction, and cannot be filled to every corner. There was a problem in workability. On the other hand, foamed synthetic resin particles have the disadvantage of flammability, and are unsuitable for applications and places where fire protection is required. In addition, because of its low specific gravity, there are problems such as poor dispersibility even when it is attempted to mix it with cement or the like as a lightweight aggregate.

[0004] Therefore, the present invention provides a flame-retardant or non-flammable property of a synthetic resin foam particle while making use of its features such as heat insulation and light weight, thereby making it possible to provide a ceiling or floor of a house. It is an object of the present invention to provide a novel heat-insulating coated granule that enables applications and construction methods such as laying in a space or blowing into a void portion, thereby improving the efficiency of heat-insulating work. It is another object of the present invention to provide a heat-insulating coated granule as a lightweight aggregate having good dispersibility when mixed with cement or the like.

[0005]

According to a first aspect of the present invention, there is provided a synthetic resin having a surface treated by forming a coating comprising sepiolite and an aqueous organic binder containing a water-soluble resin as a main component. Insulating coating characterized by further coating the foam particles with a coating material comprising an inorganic powder and an aqueous inorganic binder containing water glass containing an alkali metal silicate as a main component, followed by drying and curing. Granules.

According to the first aspect of the present invention, the surface treatment coating first formed on the synthetic resin foam particles modifies the surface of the foam particles to be hydrophilic, and forms the synthetic resin foam particles. It has the flexibility to follow the expansion and contraction. As a result, the water-based inorganic binder becomes more familiar, and the coating of the subsequently formed coating material becomes more uniform. In addition, the coating for surface treatment acts as a buffer layer between the soft synthetic resin foam particles and the coating of the coating material, and makes the coating of the coating agent hard to be broken.

Further, in the heat-insulating coated particles obtained by the present invention, the coating of the hard and heat-resistant coating material protects the whole foam particles, thereby increasing the physical strength and increasing the flame and high heat. The foam particles are less likely to ignite even when exposed to water. Furthermore, the heat-insulating coated particles have a moderately high specific gravity by the amount of the coating to improve dispersibility in cement and the like, and new properties are imparted or modified according to the inorganic powder to be coated. It was done.

A second invention according to a second aspect of the present invention is to form a coating comprising sepiolite and an aqueous organic binder having a water-soluble resin as a main component, and to form a coating on the surface of a plurality of synthetic resins as a main material. A kneaded material containing foam particles and an aqueous inorganic binder containing water glass containing an alkali metal silicate as a main component is granulated into granules, and then dried and cured, and is heat-insulated. Coated granules.

According to the second aspect of the present invention, the surface treatment coating formed on the synthetic resin foam particles modifies the surface of the foam particles to be hydrophilic, and expands and contracts the synthetic resin foam particles. It has the flexibility to follow. As a result, the aqueous inorganic binder becomes easily compatible, and the kneaded material prepared subsequently has a state in which a plurality of foam particles as a main material are well dispersed. Further, the coating for surface treatment functions as a buffer layer between the foamed particles of the soft synthetic resin and the continuous layer of the aqueous inorganic binder, and makes the hardened continuous layer of the water glass hard to be broken.

[0010] The kneaded material prepared next is in a wet state and is formed into a required shape. Thereafter, the cured continuous layer of water glass is formed by drying, and the whole foam particles are further covered with this continuous layer, and the foam particles are formed into a granular form in which a plurality of foam particles are bound. In the resulting heat-insulated coated granules, the formed hard and heat-resistant continuous layer protects the entire synthetic resin foam particles, thereby increasing the physical strength and exposing to flames or high heat. In this case, the foam particles are less likely to ignite. Also,
The heat-insulating coated particles have the properties of foam particles of a synthetic resin, are appropriately larger than individual foam particles, and are easy to handle.

According to a third aspect of the present invention, there is provided a method of forming a coating comprising a sepiolite and an aqueous organic binder having a water-soluble resin as a main component and treating the surface with a plurality of synthetic resins as a main material. The kneaded material containing foam particles and an aqueous inorganic binder containing water glass containing an alkali metal silicate as a main component is granulated into granules, then dried and cured, and further calcined to obtain the synthetic resin. Characterized in that the foam particles are burned off.

According to the third aspect, the coating for surface treatment applied to the synthetic resin foam particles modifies the surface of the foam particles to hydrophilicity. As a result, the aqueous inorganic binder becomes easily compatible, and the kneaded material prepared subsequently has a state in which a plurality of foam particles as a main material are well dispersed. The final baking burns out the synthetic resin foam particles and the like, and forms a state in which many pores are dispersed. In addition, other inorganic components are sintered, and the shape thereof is favorably maintained by the sintering property of sepiolite. The heat-insulating coated particles obtained thereby have a low specific gravity and moisture absorption / desorption properties because they are porous, and are substantially nonflammable because they are composed only of inorganic substances.

According to a fourth aspect of the present invention, in addition to the constitution of the first or second aspect, the synthetic resin foam particles are made of closed-cell type expanded polystyrene particles.

According to the fourth aspect of the present invention, since the closed-cell-type expanded polystyrene particles having a completely hollow inside are used as the synthetic resin expanded particles, the voids inside the particles are reduced to the outside. Never connected. For this reason, heat is less likely to be transmitted than in the case where non-closed cell type synthetic resin foam particles are used.

According to a fifth aspect of the present invention, in addition to the constitution of any one of the first to fourth aspects, zinc borate as a curing agent for the water glass is added to the aqueous inorganic binder. Including.

According to the fifth aspect, the zinc borate comprises:
It has the effect of accelerating the curing (gelling) of water glass with a relatively small amount of addition, and its moderate curing accelerating action makes it easy to adjust the curing time and speed. Further, since metal ions can be fixed very stably by reaction with zinc borate, there is no whitening due to elution of alkali metal, and the polymerized alkali metal silicate does not redissolve. Furthermore, since zinc borate reacts with water glass to increase the melting point, heat resistance during firing is increased.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the heat-insulating coated particles of the first, fourth, and fifth inventions will be described in more detail. They are,
Basically, foamed synthetic resin particles subjected to surface treatment with sepiolite and an aqueous organic binder containing a water-soluble resin as a main component, from an inorganic powder and an aqueous inorganic binder containing water glass as a main component Coating material, and then dried and cured.

The synthetic resin foam particles are particles whose interior is not solid but completely or incompletely hollow.
As the foam particles of the synthetic resin, polystyrene, styrene-based synthetic resin, and foams of polyethylene and polypropylene can be used. Among these, foamed polystyrene particles (hereinafter, referred to as “expanded polystyrene particles”) are particularly capable of adjusting a wide specific gravity distribution and particle size distribution, and are also excellent in heat insulation properties and the like. Specifically, the expanded polystyrene particles have a particle size of 0.5 to 10.0 mm, a tap density of 0.01 to 0.10 g / cm ³ , and a particle density of 0.015 g / cm ³ .
0.15 g / cm ³ and a thermal conductivity of 0.038 to 0.04
It is as low as 5 kcal / (m · h · ° C), and the melting start temperature is about 120 ° C.

Sepiolite is a hydrated magnesium silicate clay mineral in a fine fibrous form, also commonly called mountain leather. Sepiolite is
It has a three-dimensional chain-like crystal structure in which bricks are alternately stacked, and tunnel-like pores are formed in the chain-like gaps along the fiber length direction. Therefore, its specific surface area is as large as 300 m ² / g, and its surface contains many hydroxyl groups (—OH) and silanol groups (—SiOH) coordinated with highly reactive magnesium. The tunnel-shaped pores contain water of crystallization as binding water, and the crystal structure is maintained. Sepiolite is hydrophilic and adsorbs water well, and has other basic properties such as self-consolidation, dispersibility, thixotropic (thixotropic) properties and sinterability. The sepiolite used in the present invention is in the form of short fibers dispersed in primary particles and has a fiber length of 7 μm.
Below, the aspect ratio is 8 or more, more preferably the fiber length is 5μ.
Those having an aspect ratio of about 10 and a length of about m are preferable.

As the water-soluble resin used for the aqueous organic binder, specifically, polyvinyl alcohol (PV)
A), polyvinyl acetal, polyvinyl acetate, and the like. In the present invention, polyvinyl alcohol can be particularly preferably used. Polyvinyl alcohol is a white or slightly yellow water-soluble powder, also abbreviated as poval. Polyvinyl alcohol has a glass transition temperature of 65
It is excellent in tensile strength, compressive strength, impact resistance and abrasion resistance at -80 ° C, and is used as a raw material for producing polyvinyl alcohol fiber and polyvinyl acetal, paint, adhesive and emulsifier.

The inorganic powder used for the coating material is
There is no particular limitation, and examples thereof include ceramic powders such as kaolin, alumina, and silica, and functional powders such as sepiolite, diatomaceous earth, and zeolite.
Ceramic powder is a raw material powder mainly used to produce sintered ceramics by firing. To obtain a better sintered body, properties such as submicron particle size, narrow particle size distribution, good crystallinity, etc. It has.

In particular, a functional inorganic powder as a coating material
The use of multi-layers allows for multi-functionalization of heat-insulating coated particles.
Can be. For example, using the diatomaceous earth or zeolite
By doing so, humidity control can be imparted. Humidity control
The property is a property that keeps the indoor temperature constant,
It is a property also called sex and respiration. Diatomaceous earth is
A single-celled algae is deposited on the bottom of the sea or lake, causing
Is decomposed, and ashes of mainly silicic acid accumulate to form a stratum
It is a siliceous sedimentary rock that has the general formula SiO_Two・ XH _TwoIn O
expressed. Diatomaceous earth is made of a circular or needle-shaped boat
) And has very many fine pores.
Diatomaceous earth has a low density due to its microporous structure and is thermally insulated
Rich in properties and resistant to chemical attack.

Zeolites are group 1A and 2A of the periodic table.
There are crystalline aluminosilicates of group III elements, for example, elements such as Na, K, Mg, Ca, etc., which are naturally produced and artificially synthesized. The framework structure of zeolite has communicating voids, which are occupied by cations and water molecules. Then, water molecules are removed by the application of heat, and the voids adsorb gases, salts, and other substances. Typical natural zeolites are mortenite powders. Typical synthetic zeolites are powders using sodium silicate as a silica source and sodium aluminate as an aluminum source.

Water glass is a viscous aqueous solution containing an alkali metal silicate represented by the general formula M ₂ O.nSiO ₂ as a main component, and hardens to form a vitreous silicate polymer. In the formula, M is an alkali metal, and is typically Na, K, or Li. n is a molar ratio between M ₂ O and SiO _2, and generally 1.6 ≦ n ≦ 4.5. The type of alkali metal is a factor that affects the performance of the binder. Generally, the adhesive strength decreases in the order of Na>K> Li, and the water resistance decreases in the order of Li>K> Na. Water glass has excellent adhesiveness to ceramics, metals, etc. and is nonflammable, so it is widely used as a binder for inorganic paints and inorganic adhesives and as a binder in the production of nonflammable panels and boards. . As such water glass, water glass of sodium silicate which is inexpensive and easily available as a JIS standard product can be particularly preferably used. It is also preferable to use a water glass of lithium silicate mixed with the water glass of sodium silicate. Thereby, the water resistance after curing can be further increased.

Since the above-mentioned water glass takes a relatively long time to cure, it is common to use a curing agent for accelerating the curing. As a curing agent for water glass, zinc borate is particularly advantageous. Zinc borate has long been used as a flame retardant for paints and resin molded products.
Generally a hydrate represented by a composition of _{2ZnO · 3B 2 O 3 · 3.5H} 2 O, easily becomes anhydrate by heating. In the present invention, any of these forms can be equally used. The particle size of the zinc borate used is arbitrary, but a relatively small particle is preferable from the viewpoint of reactivity and dispersibility, and a particle having an average particle size of 1 to 100 μm is particularly preferable. Accordingly, as zinc borate, those commercially available as flame retardants can be suitably used as they are.

The preparation of the particulate heat-insulating coated particles is carried out as follows. First, an aqueous organic binder is applied to foam particles of a synthetic resin, and sepiolite as a surface treatment material is adhered and coated thereon, thereby performing a surface treatment. The aqueous organic binder containing a water-soluble resin as a main component blends well with the synthetic resin foam particles, and is evenly applied to the surface thereof. Sepiolite, which is hydrophilic, can be dispersed in an aqueous organic binder and can evenly spread over the surface of the foam particles coated with the binder. Next, the aqueous organic binder is dried and adhered by the water-soluble resin, and the sepiolite is consolidated by its self-consolidating property, whereby a substantially uniform coating having hydrophilicity and flexibility is formed.

The flexibility of the coating is considered to be due to the following mechanism. As schematically shown in FIG. 1, primary particles 12 of short fibrous sepiolite are adhered to the surface of synthetic resin foam particles 11 by a flexible water-soluble resin 13. Primary particles 12 form a matrix with each other, and the intersections of the matrix are connected by a water-soluble resin 13. Due to this higher order structure of the sepiolite particles, the coating 14 is flexible,
Even on the surface of an elastic material such as synthetic resin,
Following the expansion and contraction, it is possible to form a coating that is less likely to crack or peel. Further, by acting as a buffer layer between the subsequently formed inorganic coating 15,
The hard inorganic coating 15 can be made hard to break.

Next, an aqueous inorganic binder is applied to the foam particles having been subjected to the surface treatment, and an inorganic powder as a coating material is adhered thereto and coated. The surface of the foam particles modified to be hydrophilic is easily blended with the aqueous inorganic binder containing water glass as a main component, and is evenly applied to the surface. Thereby, the inorganic powder can be coated substantially uniformly. Immediately after coating with the inorganic powder, the aqueous inorganic binder is in a wet state, and it is necessary to dry and cure the binder. At this time, curing is preferably promoted by heating and drying. By hardening the water glass of the aqueous inorganic binder, the inorganic powder is firmly bound to the surface of the synthetic resin foam particles.

The particulate heat-insulating coated particles prepared by the above steps are obtained by forming a coating mainly composed of inorganic powder on the surface of synthetic resin foam particles. Covers the entirety of the synthetic resin foam particles. This increases the physical strength of the foam particles, imparts flame retardancy, and makes the synthetic resin less prone to flame even when exposed to a flame or high heat. Therefore, the heat-insulating coated particles can be used as a heat-insulating material that can be filled into a gap such as an outer wall of a house where fire protection is required by a blowing method. In addition, the surface of the particles is modified to be hydrophilic by the formed coating, and the specific gravity is appropriately increased by the amount of the coating, thereby improving the affinity with cement and the like and the dispersibility when mixing. It can be used as an easy-to-use lightweight aggregate.

In particular, in the case of using a closed-cell type in which the inside is completely hollow as the synthetic resin foam particles, it is effective in further enhancing the heat insulating property of the coated particles. When the closed-cell type is used, the voids inside the particles do not connect to the outside, so that the coating formed on the surface of the particles does not enter the interior and fill the voids. Therefore, as compared with the case of using the non-closed cell type, more voids inside the particles remain, and even if there is no or very little flow of gas such as air, heat is hardly transmitted.

Further, by adding zinc borate as a curing agent for water glass to the aqueous inorganic binder, the curing can be accelerated. The effect of zinc borate as a curing agent is considered to be due to the following phenomena. When water glass and zinc borate are mixed, boric acid and zinc that have been chemically bonded are dissolved on the surface of zinc borate. The boric acid and zinc react with the alkali metal of the alkali metal silicate of the water glass to form a new compound, thereby fixing the alkali metal.
The silicate that has lost the alkali metal gels and precipitates on the surface of the fine powder of zinc borate, forming a glassy solid. The deposition of the silica gel proceeds in this manner, and the expanded silica gel is integrated with the silica gel deposited on the surface of the adjacent fine powder of zinc borate, and eventually the whole gels.
The gelation proceeds relatively slowly when the amount of zinc borate in the curing agent is small, but proceeds rapidly as the amount increases. Therefore, the curing time and speed can be easily adjusted by the amount of zinc borate added. Furthermore, since the alkali metal is immobilized by the addition of zinc borate, the formed cured body of water glass does not have the so-called whitening caused by the elution of the metal ion. In addition, the polymerized alkali metal silicate does not redissolve and becomes chemically stable.

Next, the heat-insulating coated particles of the second, fourth, and fifth inventions will be described in more detail. These are basically a plurality of synthetic resin foam particles as a main material whose surface is treated with a sepiolite and an aqueous organic binder mainly containing a water-soluble resin, and an aqueous particle mainly containing water glass. A kneaded product containing an inorganic binder is granulated into granules, and then dried and cured.

The synthetic resin foam particles, sepiolite, water-soluble resin, water glass and its curing agent used here are as described above, but the aqueous inorganic binder containing water glass as a main component is used. In order to prevent cracking during curing and improve the strength of the cured product, an inorganic fiber may be added as a reinforcing material. Specifically, for example, mineral fibers such as glass fibers and rock wool fibers, metal fibers such as stainless steel fibers, carbon fibers, alumina fibers, alumina silica fibers, ceramic fibers such as potassium titanate fibers, and inorganic compound fibers such as whiskers. And the like. Among these, glass fibers are preferred in that they are inexpensive.

The granular heat-insulated coated granules are prepared through four steps. In the first step, the surface of the synthetic resin foam particles is treated with sepiolite and an aqueous organic binder. The method is the same as the above-mentioned method for the particulate heat-insulating coated particles. By this surface treatment, a substantially uniform coating having hydrophilicity and flexibility is formed.

In the second step, foamed particles of a synthetic resin as a main material subjected to a surface treatment and an aqueous inorganic binder are mixed to form a slurry of a kneaded material in which the foamed particles are substantially uniformly dispersed. In this slurry, since the surface of the foam particles is modified to be hydrophilic by the above-described surface treatment, the foam particles are unlikely to aggregate with each other, and the individual particles are in a state of being well dispersed.

In the third step, the slurry of the kneaded material is granulated into granules. The size and shape of the granules are arbitrary, but are preferably spherical having a diameter of 10 mm or less in view of the granulation properties of the slurry and the curing time of the water glass. When the granulation property is not good due to insufficient viscosity of the aqueous inorganic binder, it is advisable to add a component for compensating the viscosity. For example, methylcellulose as a gelling agent is added. This methylcellulose exerts its effect in a small amount and is flame-retardant, so that it hardly affects the required properties of the resulting heat-insulated coated granules. In addition, since methylcellulose imparts thixotropic properties, dripping of the aqueous inorganic binder can be suppressed, and the form can be favorably maintained after granulation until the water glass is hardened.

[0037] Sepiolite used for surface treatment also has thixotropic properties. Therefore, it is more preferable to add the sepiolite slightly in excess of the required amount as the above-mentioned surface treatment material, whereby the shape retention effect after granulation can be further improved.

In the fourth step, the granules are dried and hardened. Since the granule immediately after granulation is still in a wet state and its form is not stable, it needs to be dried and hardened promptly. In particular, the larger the granules, the longer it takes to dry. Therefore, it is preferable to promote the curing by heating and drying. This forms a hardened continuous layer of water glass,
A plurality of foam particles form a granule in which they are firmly bound.

In the granular heat-insulating coated particles prepared by the above steps, the formed hard and heat-resistant continuous layer functions to protect the synthetic resin foam particles. This increases the physical strength of the foam particles, imparts flame retardancy, and makes the foam particles less likely to ignite when exposed to a flame or high heat. Further, while having the properties of the foamed particles of the original synthetic resin such as heat insulating properties and light weight, it is moderately larger than individual foamed particles, and handling becomes easy.
Therefore, the heat-insulating coated particles can be uniformly spread on a ceiling or a floor of a house where fire protection is required, or can be filled into a gap of an outer wall by a blowing method, and the efficiency of construction work can be improved. Can be used as a good heat insulator.

In particular, when a closed cell type having a completely hollow inside is used as the synthetic resin foam particles, it is effective in further improving the properties such as heat insulation. When the closed-cell type is used, the voids inside the particles do not connect to the outside, so that the continuous layer formed around the particles does not enter the interior and fill the voids. For this reason, more voids inside the particles remain than in the case of using the non-closed cell type, and even if there is no or very little flow of gas such as air, heat is hardly transmitted, and low specific gravity and Because it becomes.

The curing can be accelerated by adding an appropriate amount of zinc borate as a curing agent for water glass to the aqueous inorganic binder. Furthermore, since the alkali metal is immobilized by the addition of zinc borate, the formed cured body of water glass does not have the so-called whitening caused by the elution of the metal ion. In addition, the polymerized alkali metal silicate does not redissolve and becomes chemically stable.

Further, when the water glass is cured, a dehydration condensation reaction takes place, so that the cured product substantially does not contain water of crystallization and forms numerous fine pores. This contributes to the weight reduction of the heat-insulating coated particles, and is greatly different from the case where a hydrated type such as cement is used as the aqueous inorganic binder. When a hydrated aqueous inorganic binder is used, water is taken in at the time of curing, so that water remains as it is and the weight hardly changes. In contrast, when an aqueous inorganic binder containing water glass as a main component is used,
As water evaporates during drying, the weight is reduced accordingly.

In the above-mentioned granular heat-insulating coated particles, the strength, specific gravity, and granulation properties of the slurry of the kneaded material vary depending on the composition of each component. When the mixing ratio of the foam particles of the synthetic resin as the main material and the aqueous inorganic binder as the dispersion medium is changed to increase the proportion of the dispersion medium, the strength of the heat-insulating coated granules is improved, but The specific gravity tends to be high due to high specific gravity and low viscosity of the slurry. Conversely, if you increase the proportion of the main material,
Although the specific gravity can be made lower, the strength tends to decrease, and if the dispersion medium is extremely insufficient, granulation becomes impossible. Therefore, it is necessary to adjust the mixing ratio of the two components while considering the balance between the contradictory performances of the strength enhancement and the low specific gravity.

In order to improve the strength of the heat-insulating coated particles, it is also effective to carry out a strengthening treatment by coating with a coating agent. Specifically, for example, by using a colloidal silica-based inorganic coating agent or the like, the strength can be improved without substantially affecting the required characteristics of the heat-insulating coated particles. Colloidal silica is silica particles dispersed in a binder and is mainly composed of SiO ₂ . The reaction between Na ⁺ in the binder and boric acid in the curing agent and the condensation reaction of silicate by dehydration of water in the binder form Si—O—Si bonds, which are cured by three-dimensional crosslinking. These reactions proceed at room temperature, but can be further promoted by heating to about 40 ° C.

Next, the heat-insulating coated particles of the third and fifth inventions will be described in more detail. These are basically a plurality of synthetic resin foam particles as a main material whose surface is treated with a sepiolite and an aqueous organic binder mainly containing a water-soluble resin, and an aqueous particle mainly containing water glass. The kneaded product containing the inorganic binder is granulated into granules, dried and cured, and further calcined.

The synthetic resin foam particles, sepiolite, water-soluble resin, water glass and its hardener used here are as described above, but the synthetic resin foam particles here are pores. It also functions as a forming material, and pores corresponding to the particle size of the foam particles used are formed by firing.

In addition, an aqueous inorganic binder containing water glass as a main component is used as a reinforcing material for the purpose of preventing cracks from occurring during drying and firing and improving the strength of the finally obtained heat insulating coated particles. Fibers may be added. Specific examples thereof include mineral fibers such as glass fibers and rock wool fibers, carbon fibers, alumina fibers, alumina silica fibers, ceramic fibers such as potassium titanate fibers, and inorganic compound fibers such as whiskers. Among these, glass fibers are preferred in that they are inexpensive.

The heat-insulating coated granules are prepared through five steps. The first to fourth steps are performed in the first to fourth steps in the above-mentioned granular heat-insulating coated particles. Can be performed in the same manner as in the above steps. The fifth firing step, which is performed after the fourth step, is performed for the purpose of burning off organic components such as foam particles of synthetic resin and curing and sintering other inorganic components. Therefore, the firing conditions are set so that the purpose can be efficiently achieved.

For example, when foamed polystyrene particles are used as the main material and an aqueous inorganic binder mainly composed of water glass is used as the dispersion medium, the maximum firing temperature is set to 600 to 700.
By setting the temperature and the firing time to about 1 to 2 hours, the desired non-combustible heat-insulating coated particles can be obtained. At this time, the hardened body of water glass having a melting point around 700 ° C. is softened, so that pores generated when the polystyrene melted and gasified with the temperature rise is diffused to the outside are closed, and the water glass is melted. The cured body itself shrinks and becomes harder.

Sepiolite used for surface treatment has a sintering property, and when exposed to a flame or high heat, sinters from a relatively low temperature (about 550 ° C.) and becomes ceramic when the temperature rises. , To keep its shape well. Therefore, it is more preferable that the sepiolite is added in a slightly excessive amount than the above-mentioned required amount as the surface treatment material, whereby the shape of the heat insulating coated particles can be favorably maintained even during firing.

In the non-combustible heat-insulating coated particles prepared by the above-described steps, the main material and the foamed particles of the synthetic resin as the pore-forming material are burned off by firing, and the aqueous inorganic binder as the dispersion medium is burned. Water glass or the like is hardened and sintered, and a large number of pores are formed by burning out the foam particles. Accordingly, the heat-insulating coated granules are porous and have low specific gravity and moisture absorption / release properties, and are substantially nonflammable because they are made of only inorganic substances. Therefore, the heat-insulating coated particles can be uniformly spread on a ceiling or a floor of a house, etc., and can be used as a heat-insulating material having high efficiency of construction work and having moisture absorption / desorption property and nonflammability. Also,
Since it is porous and has moisture absorption / desorption properties, and is made of only inorganic material and has excellent chemical stability, it can be used as porous spherical silica having a function as a carrier for a drug, a catalyst, or the like.

By adding an appropriate amount of zinc borate as a curing agent for water glass to the aqueous inorganic binder, the curing of the water glass during drying can be accelerated. Furthermore,
Since the alkali metal is immobilized by the addition of zinc borate, the formed cured body of water glass does not have the so-called whitening caused by the elution of the metal ion.
In addition, the polymerized alkali metal silicate does not redissolve and becomes chemically stable. In addition, since zinc borate reacts with water glass to increase the melting point, the heat resistance of the cured water glass during firing can be increased.

In this non-combustible heat-insulating coated particle, as in the case of the above-mentioned granular heat-insulating coated particle, foam particles of a synthetic resin as a main material and an aqueous inorganic binder as a dispersion medium are used. The strength, specific gravity, and the like change according to the composition. That is, when the proportion of the dispersion medium is increased, the strength is improved but the specific gravity is increased. Conversely, when the proportion of the main material is increased, the specific gravity can be reduced but the strength is reduced.

In order to improve the strength of the heat-insulating coated particles, it is also effective to carry out a strengthening treatment by coating with a coating agent. Specifically, for example, by using a colloidal silica-based inorganic coating agent or a polyisocyanate / colloidal silica-based organic-inorganic composite coating agent, etc., the required properties of the heat-insulating coated particles are hardly affected. , Its strength can be improved.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

(First Embodiment) The particulate heat-insulating coated particles (hereinafter referred to as "coating particles") of the present embodiment are made of synthetic resin foam particles, a surface treatment material, an aqueous organic binder, a coating material, It consists of an aqueous inorganic binder.
The synthetic resin foam particles are expanded polystyrene particles (trade name: HB-S (manufactured by Hitachi Chemical Co., Ltd.)
mm)). The surface treatment material is made of sepiolite (trade name: Aid Plus P-4 manufactured by Mizusawa Chemical Industry Co., Ltd.). The aqueous organic binder is composed of a binder A made of an aqueous solution of polyvinyl alcohol (PVA). The coating material is made of ceramic powder (trade name: CeraP, manufactured by Seto Ceramic Industry Co., Ltd.). The aqueous inorganic binder consists of a binder B made of a solution obtained by diluting water glass consisting of 70 parts by weight of sodium silicate, 35 parts by weight of lithium silicate and 1 part by weight of zinc borate with twice the weight of water. The details of each material composition and components for preparing the coating particles of this example are shown in Table 1 below (however, the blending shows a relative amount).

[0057]

[Table 1]

Using the above materials, coating particles were prepared in the following procedure. First, the expanded polystyrene particles were put into a mixer, Binder A was added, and the mixture was stirred at a rotation speed of 120 rpm for 3 minutes. Next, add sepiolite and add 120r
The mixture was stirred at a rotation speed of pm for 3 minutes. Subsequently, ceramic powder A was added and stirred at a rotation speed of 120 rpm for 3 minutes,
The mixture A was transferred to a hot plate and dried by heating at 50 ° C. for 5 minutes. Further, the dried mixture A was again put into the mixer, the binder B was added, and the mixture was stirred at a rotation speed of 120 rpm for 1 minute. Next, the ceramic powder B was added and stirred at a rotation speed of 120 rpm for 1 minute. Thereafter, the mixture B was transferred onto a hot plate and dried by heating at 50 ° C. for 10 minutes. According to the above procedure, as shown in FIG. 2, a coating layer 3a composed of binder A, sepiolite and ceramic powder A, and a coating layer 3b composed of binder B and ceramic powder B are formed on the hollow expanded polystyrene particles 2. Doubly formed, coated particles 1 were prepared.

(Second Example) The granular heat-insulating coated particles (hereinafter referred to as "heat-insulating particles") of this example are made of synthetic resin foam particles, a surface treatment material, an aqueous organic binder and an aqueous inorganic binder. Consists of The synthetic resin foam particles are expanded polystyrene particles (trade name: H, manufactured by Hitachi Chemical Co., Ltd.).
BS (average particle size 0.8 mm)). The surface treatment material is
It consists of sepiolite (trade name: Aid Plus P-4, manufactured by Mizusawa Chemical Industry Co., Ltd.). The aqueous organic binder is composed of a binder C composed of an aqueous solution of polyvinyl alcohol (PVA). The aqueous inorganic binder is sodium silicate 7
Binder D was prepared by adding 1/50 parts by weight of methylcellulose to water glass comprising 0 parts by weight, 35 parts by weight of lithium silicate and 1 part by weight of zinc borate. The details of each material composition and components for preparing the heat insulating particles of this example are shown in Table 2 below.
(However, the formulation shows a relative amount).

[0060]

[Table 2]

Using the above materials, heat insulating particles were prepared in the following procedure. First, the expanded polystyrene particles were placed in a mixer, Binder C was added, and the mixture was stirred at a rotation speed of 120 rpm for 5 minutes. Next, sepiolite was added thereto, and the mixture was stirred at a rotation speed of 120 rpm for 10 minutes until there was no flour, thereby obtaining a mixed product C. Then, the binder D is added to the mixture C, and
The mixture was stirred at a rotation speed of pm for 10 minutes to obtain a dispersion slurry. This slurry was granulated into particles having a size of about 10 mm, and dried by heating at 40 ° C. for 6 hours in a drier. By the above procedure, as shown in FIG. 3, the coating layer 6 composed of the binder C and the sepiolite is formed on the hollow expanded polystyrene particles 5, and the plurality of particles are formed by the continuous layer 7 composed of the binder D and the sepiolite. Insulating granules 4 granulated into granules were prepared.

Further, the above heat-insulating particles were subjected to a strengthening treatment by coating with an inorganic coating agent. The coating agent is composed of a one-pack type inorganic binder (trade name: FJ-294, manufactured by Tokiwa Denki Co., Ltd.) containing colloidal silica as a main component and water as a dispersion medium. It was dried by heating at 80 ° C. for 20 minutes in a drier. By comparing the hardness of the heat-insulated particles obtained before and after the treatment by strongly pressing the obtained heat-insulated particles with a finger, the effect of improving the strength could be confirmed.

(Third Embodiment) The non-combustible, heat-insulating coated particles (hereinafter referred to as "spherical silica") of this embodiment are the same as those of the second embodiment.
It was prepared with the same material composition and components as the insulating particles in the examples. In addition, the preparation method was the same as that until the dispersion slurry was obtained.

The prepared slurry is granulated into granules having a size of about 10 mm, and first dried at 60 ° C. for about 2 hours in a drier.
Subsequently, the temperature was raised to 120 ° C. and drying was performed for 1 hour. This was transferred to a firing kiln, first heated at 200 ° C. for 1 hour, then heated to 600 ° C. and heated for 1 hour, and further heated to 700 ° C. and fired for 1 hour. By the above procedure, as shown in FIG. 4, spherical silica 8 which was a sintered body of sepiolite and a water glass composition and had many pores 9 generated by burning out of the expanded polystyrene particles was prepared.

Further, the above-mentioned spherical silica was strengthened by coating with an organic-inorganic composite coating agent.
The coating agent is a one-pack type organic-inorganic composite coating agent (trade name: FJ-801, manufactured by Tokiwa Denki Co., Ltd.) containing polyisocyanate and colloidal silica as main components and xylol as a dispersion medium. It was immersed in a coating agent and then dried by heating at 160 ° C. for 20 minutes in a dryer. By comparing the hardness of the obtained spherical silica with that before treatment by strongly pressing it with a finger, the effect of improving the strength could be confirmed.

[0066]

As described above, according to the first aspect of the present invention, by subjecting the synthetic resin foam particles to a surface treatment using sepiolite or the like, the inorganic powder or the like as the coating material is substantially uniform and durable. The heat insulating coated particles in the form of particles can be obtained. In addition, by forming a coating with an inorganic powder or the like, a property such as heat resistance or the like provided by the inorganic powder is imparted or modified while utilizing features such as heat insulation and light weight of the synthetic resin foam particles. can do.
Further, since physical strength and flame retardancy are imparted, it can be used as a heat insulating material that can be filled into a gap in an outer wall by a blowing method. In addition, since the dispersibility in cement or the like is improved, the workability when mixing as a lightweight aggregate can be improved.

According to the second aspect of the invention, by subjecting the synthetic resin foam particles to a surface treatment using sepiolite or the like, aggregation of the synthetic resin foam particles can be prevented. Can be obtained in a state where the foam particles are substantially uniformly dispersed in the aqueous inorganic binder. In addition, by using the aqueous inorganic binder, flame retardancy can be imparted while utilizing the properties of the synthetic resin foam particles such as heat insulation and light weight. Furthermore, since the dispersed slurry is in a wet state, it can be easily formed into a desired shape, and is granulated into a granule having a size that is easy to handle. Coated granules can be obtained.

According to the third aspect, by subjecting the synthetic resin foam particles to a surface treatment using sepiolite or the like, it is possible to prevent aggregation of the synthetic resin foam particles, whereby the Granules in a state of being substantially uniformly dispersed in the inorganic binder can be obtained. Also, the shape can be favorably maintained during firing. Further, by calcining, it is possible to obtain heat-insulating coated particles as a heat-insulating material that is porous, has low specific gravity, absorbs and desorbs moisture, and is substantially nonflammable. In addition, it can be used as porous spherical silica having a function as a carrier for a drug, a catalyst, or the like.

According to the fourth aspect, in addition to the effects of the first or second aspect, characteristics such as heat insulation can be further enhanced.

According to the fifth aspect, in addition to the effects of any one of the first to fourth aspects, the curing of the water glass can be promoted. Further, the cured body of the water glass can be made stable without whitening or redissolving. Further, heat resistance during firing can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a fine structure of a coating for surface treatment formed on synthetic resin foam particles.

FIG. 2 is a front view showing a part of the heat-insulating coated particles (coating particles) in the first embodiment in a broken state.

FIG. 3 is a front view of a part of a granular heat-insulating coated granule (heat-insulating grain) in a second embodiment, which is cut away.

FIG. 4 is a front view showing a part of a non-flammable heat-insulating coated granule (spherical silica) in a third embodiment in a cutaway manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating particle 2,5 Expanded polystyrene particle 3a, 3b, 6 Coating layer 4 Thermal insulation particle 7 Continuous layer 8 Spherical silica 9 Void

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kozo Hayashi 65 Metal Complex in Kakamigahara City, Gifu Prefecture Tokiwa Denki Co., Ltd. (72) Inventor Kyoichi Fujimoto 65 Metal Complex in Kakamigahara City, Gifu Prefecture Tokiwa Electric Co., Ltd. (72 ) Inventor Hideki Kishino 65 Metal Complex, Kakamigahara-shi, Gifu F-term in Tokiwa Denki Co., Ltd.

Claims (5)

[Claims] An inorganic powder and an alkali metal silicate are mainly added to foam particles of a synthetic resin which has been subjected to a surface treatment by forming a coating comprising sepiolite and an aqueous organic binder containing a water-soluble resin as a main component. A heat-insulating coated particle obtained by further coating a coating material comprising an aqueous inorganic binder containing water glass as a component, and then drying and curing. 2. A synthetic resin foam particle as a main material which has been subjected to a surface treatment by forming a coating comprising a sepiolite and an aqueous organic binder containing a water-soluble resin as a main component, and an alkali metal silicate. A heat-insulating coated particle obtained by granulating a kneaded product containing an aqueous inorganic binder containing water glass as an essential component and then drying and hardening the mixture. 3. A synthetic resin foam particle as a main material which has been subjected to a surface treatment by forming a coating comprising a sepiolite and an aqueous organic binder mainly containing a water-soluble resin, and an alkali metal silicate. A kneaded product containing an aqueous inorganic binder containing water glass as an essential component is granulated into granules, then dried and cured, and further fired to burn out the synthetic resin foam particles. Heat-insulating coated particles. 4. The heat-insulating coated particles according to claim 1, wherein the synthetic resin foam particles are made of closed-cell type expanded polystyrene particles. 5. The heat-insulating coated particles according to claim 1, wherein the aqueous inorganic binder contains zinc borate as a curing agent for the water glass.