JP2003313062A - Hydraulic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic composition with which inorganic latent heat accumulative building materials having a reduced dimensional change at about a phase transition temperature can be produced. <P>SOLUTION: The hydraulic composition contains a hydraulic material, a microcapsule involving a latent heat accumulative material and a microcapsule involving a latent heat accumulative material including porous inorganic powder. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic composition suitable for use in walls, floors, ceilings and the like to obtain an inorganic building material capable of forming a heat storage structure in general buildings and houses.

[0002]

2. Description of the Related Art In recent years, in the construction of houses and the like, a method of attaching a board building material to a structural body has been widely used. Since the board building material itself does not have to have strength as a frame, it is possible to construct a house with lightweight and thin members, which contributes significantly to the simplification of construction and shortening the construction period.

However, in such a house, the heat capacity of the building is often extremely small. Therefore, the room temperature and the wall surface temperature are sensitively linked to the external environment temperature, and the temperature change in the room tends to increase. Therefore, it is the current situation that the thermal insulation performance is improved and the comfortable temperature is maintained by using the air conditioning equipment which consumes a large amount of energy such as electric power and gas.

On the other hand, an attempt is made to improve comfort and energy saving by applying so-called heat storage technology, which stores solar heat, heat from air conditioning, and the like, and takes out the heat when necessary. It is being appreciated.

However, in order to secure a sufficient heat storage capacity, a corresponding volume is required, and in a building other than a building in which the skeleton itself is made of concrete or the like, a corresponding space for newly installing a heat storage member. Had to be secured.

[0006] Methods such as pouring concrete or laying bricks or sand are used to impart a heat storage function, but the construction management is complicated and the weight is heavy. The installation site was limited to the first floor and so on.

There are various types of board members used in houses, but they are constructed in suitable parts in consideration of the characteristics of each material. A board material using a hydraulic material such as cement or gypsum as a binder has relatively high strength and is extremely useful as a board material for a house.

Although it can be considered to use it as a heat storage member as it is, there is a problem that a sufficient heat storage capacity cannot be secured unless the plate thickness is increased, and then the weight becomes large. Therefore, it is desired to develop a new building material that has a latent heat storage function and is usable as a heat storage material while being board-shaped and lightweight.

Generally, in a hydraulic material, a hydrate formed by a hydration reaction is precipitated in interparticle voids in the composition and is filled into the voids to be hardened, so that strength appears.
There are many factors that affect the hydration reaction, and even if a material having a latent heat storage effect was mixed as it was, a sufficient immobilization effect could not be obtained, and curing failure and leakage of the contents were likely to occur due to inhibition of hydration progress. .

As a countermeasure for this, a method of separating from the hydration reaction phase by means such as microencapsulation can be considered. However, the microcapsules can be dispersed in the raw material composition without being broken, or good flow characteristics can be obtained in the molding process. Was difficult to maintain.

Further, since the latent heat storage material undergoes a discontinuous volume change at the phase transition point, its size changes even if it is microencapsulated. Therefore, there has been a problem that the volume change accompanying the phase change is directly transmitted to the cement base material, which becomes one of the causes of the deformation and crack generation of the material.

In order to realize a composite building material in which a latent heat storage material and a building material are fused, it is necessary to prevent the phase change material contained in the building material from flowing out at the time of melting. For example, JP-A-2-298759
As described in Japanese Patent Publication (Publication 1),
Means such as impregnation and integration into a resin material as disclosed in JP-A-5-1281 (publication example 2) and sealing with an aluminum laminate film as disclosed in JP-A-8-219673 (publication example 3) are disclosed. ing.

In Japanese Patent Laid-Open No. 61-235485 (known example 4), a latent heat storage material is coated with an organic coating to form fine particles having a particle size of 50 μm to 2 mm and dispersed in a base material such as concrete. ing.

However, when strong agitation is applied during kneading, the organic coating film is broken and the latent heat storage material leaks out. On the contrary, when the kneading is insufficient to avoid the destruction of the organic coating film, the uniformity of the material is impaired and the material is impaired. There was a problem such as a decrease in strength.

[0015]

However, in the above-mentioned conventional example, in the method of enclosing in the container and covering the surface as in the above-mentioned known examples 1 to 3, the processing such as cutting and punching of the heat storage material is performed. It is impossible. Further, even when the resin material having a high affinity with the phase change material is impregnated or kneaded, it is insufficient to prevent the heat storage material from leaking.

Further, in the above-mentioned known example 4, when strong agitation is applied during kneading, the organic coating film is broken and the latent heat storage material leaks out, and conversely, if the kneading is insufficient to avoid the destruction of the organic coating film, the material becomes uniform. However, there is a problem in that the material strength is deteriorated and the material strength is reduced.

The present invention is to solve the above-mentioned problems.
The purpose is to set a hydraulic composition that can be applied to latent heat storage building materials that do not require a special construction method without performance deterioration even if cutting and drilling are performed like ordinary board materials. The present invention provides a hydraulic composition that can be applied to a latent heat storage building material or the like that has a very small effect of volume change due to the phase transition of the latent heat storage material and can maintain stable member dimensions.

[0018]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems, and as a result, in dispersing and integrating a microencapsulated latent heat storage material with a hydraulic material, a porous inorganic powder was used. The present invention has been completed by finding that a material having a very small effect of volume change at the phase transition point can be obtained by coexisting with a certain amount or more.

That is, a typical constitution according to the present invention for achieving the above object is a hydraulic material, a microcapsule containing a latent heat storage material, and a microcapsule containing a latent heat storage material containing a porous inorganic powder. A hydraulic composition comprising a capsule.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the hydraulic composition according to the present invention will be described in detail below. As the heat storage material (latent heat storage material) that can be used in the present invention, tetradecane (C14), pentadecane (C15), hexadecane (C1)
6), normal paraffins such as octadecane (C18), inorganic eutectic and inorganic hydrate, fatty acids such as acetic acid and caprylic acid, aromatic hydrocarbon compounds such as benzene and p-xylene, palmitic acid Examples thereof include compounds such as isopropyl, butyl stearate, and alcohols such as decyl alcohol. Preferably, compounds having a heat of fusion of 80 kJ / kg or more, chemically and physically stable, and inexpensive are used. These may be mixed and used, and if necessary, a supercooling preventive agent, a specific gravity adjusting agent, a deterioration preventing agent and the like may be added.

In general, as a method of microencapsulating a latent heat storage material, an encapsulation method by a composite emulsion method (JP-A-62-1452) and a method of spraying a thermoplastic resin on the surface of the heat storage material particles (JP-A No. 62-45680), a method of forming a thermoplastic resin in the liquid on the surface of the heat storage material particles (JP-A-62-149334), a method of polymerizing and coating a monomer on the surface of the heat storage material particles (special The method described in, for example, JP-A No. 62-225241) and the method for producing microcapsules of polyamide film by interfacial polycondensation reaction (Japanese Patent Application Laid-Open No. 2-258052) can be used, and the description is omitted here.

As the film material of the microcapsule, polystyrene, polyacrylonitrile, polyamide, polyacrylamide, ethyl cellulose, polyurethane obtained by a method such as an interfacial polymerization method or an in-situ method can be used.
Aminoplast resin, or a synthetic or natural resin using the coacervation method of gelatin and carboxymethyl cellulose or gum arabic is used, but as in the present invention, the microcapsules are not destroyed in the matrix. Considering dispersion, it is particularly preferable to use a physically and chemically stable in-situ melamine formalin resin film and microcapsules using urea formalin resin.

In general, microcapsules having a large volume average particle size are easily broken by stirring or shearing force generated during molding. In a capsule having a large particle diameter, even if the capsule is uniformly dispersed in the base material, the interface between the base material and the capsule is likely to have a defect, and mechanical properties such as bending strength are deteriorated. In addition, there is a problem that the material is easily separated due to the difference in specific gravity from the base material.

When a capsule having a particle size significantly larger than that of the raw material powder is mixed, the flowability of the composition is significantly deteriorated due to the presence of the capsule, which is not preferable in production, and therefore the particle size of the microcapsule is 0.5 μm or more. , And 5
The range is preferably 0 μm or less.

Microcapsules having a particle size smaller than this range are technically difficult to stably produce, and not only the production cost is high, but also the surface area of the capsules is remarkably large, so that the amount of water required at the time of stirring is rather large. This is not preferable because it tends to increase and the mechanical strength of the board tends to decrease.

The microcapsule particle size of this embodiment is a volume average particle size obtained by using a particle size measuring device "Coulter Counter Multisizer" manufactured by Coulter, Inc. in the United States.

The particle size of the microcapsules depends on the type and concentration of the emulsifier, the temperature of the emulsified liquid during emulsification, the emulsification ratio (volume ratio of the water phase and the oil phase), and an atomizer called an emulsifier or disperser. The operating conditions (stirring speed, time, etc.) are appropriately adjusted to set a desired particle size.

In the latent heat storage material utilizing phase change,
Volume change occurs at the phase transition point, and the volume of the microcapsule also changes. When the microcapsules are embedded in the base material without any gaps, the change in the volume of the capsule itself is directly transmitted to the base material, so that the change in the member size becomes relatively large.

The present invention is characterized by containing a certain amount or more of the porous inorganic powder in the composition, thereby making it possible to extremely reduce the dimensional change of the material due to the volume change of the latent heat storage microcapsules. Will be possible.

Since the porous inorganic powder is chemically extremely stable, it hardly affects the hydration and strength development of cement. Since it is a porous material, microcapsules with extremely small particle size can exist in a state in which the surroundings are not strongly restrained in the pores of the powder or in the recesses on the surface, and the dimensional change of the member due to the volume change of the capsule. Alleviate. Also, if the microcapsule breaks because it is porous,
Holds the heat storage material in the pores to prevent leakage.

Examples of the porous inorganic powder used in the present invention include mineral or artificial mineral porous inorganic powders containing silicate compounds such as calcium silicate and aluminum silicate as a main component, diatomaceous earth, and pearlite. Porous inorganic powder can be used.

As the porous calcium silicate powder, for example, a foaming agent such as a foaming agent and a foaming agent are added and mixed to a slurry-like material in which a siliceous material such as silica stone is mixed with cement and a calcareous raw material such as quicklime. After that, an artificial mineral or the like obtained by foaming and hardening and curing at high temperature and high pressure steam is pulverized.

It is also possible to use a porous calcium silicate which is also a lightweight cellular concrete and grind it into a powder. Further, it is preferable to pulverize porous ceramics, bricks, etc. to obtain powder.

The content of the porous inorganic powder in the cement is preferably 50 parts by weight or more, more preferably 100 parts by weight or more and 500 parts by weight or less, based on 100 parts by weight of the cement.

If the content is more than this range, the mechanical strength of the building material is remarkably lowered, which is not preferable, and conversely, if the content is too small, the product dimensional change rate at the phase change of the heat storage material described in the present invention becomes large, which is not preferable.

The particle diameter of the porous inorganic powder is preferably 5 μm or more and 100 μm or less. If it is larger than this range, coarse pores of the powder remain, which causes defects and causes a decrease in strength.

If the volume average particle size is smaller than 5 μm, it takes a lot of energy and time to pulverize, and the productivity is lowered. The particle size of the porous calcium silicate powder of the present invention is a volume average particle size obtained by wet measurement using a laser diffraction / scattering particle size measuring device “Microtrac particle size distribution measuring device” with water as a dispersion medium. Indicates.

The phase transition temperature of the heat storage material is not particularly limited, but is preferably 5 ° C. or higher and 50 ° C. or lower for the purpose of maintaining a comfortable temperature environment. However, especially in climate climates where there is a large temperature difference between summer and winter, such as Japan, keeping the melting point of the latent heat storage material constant means that the latent heat does not function at all in any season. Therefore, it is effective to set the melting point according to the environment of the land or to combine the microcapsules in which two or more heat storage materials are separately included.

Specifically, in order to suppress the temperature rise in the room in the summer, microcapsules of a heat storage material having a melting point of about 25 ° C to 30 ° C are used, and in order to suppress the decrease in the room temperature in the winter, 10 ° C or more, In addition, it is expected that a more comfortable indoor environment can be provided throughout the year by using a building material containing two kinds of microcapsules as a heat storage material having a melting point of 20 ° C. or lower.

Further, by using a heat storage material having a relatively high phase transition temperature of 25 ° C. or higher and 50 ° C., a part of the floor heating system can be formed, or a relatively low phase transition of 5 ° C. to 25 ° C. It is also possible to form part of the cooling system by using a heat storage material of temperature.

A building material using the hydraulic composition of the present invention is
Compared with the sensible heat storage material, it does not require a large space for providing the amount of heat storage, so the heat storage function can be provided by simply attaching it to the frame structure without changing the conventional housing design. Of course, the purpose and use of the hydraulic composition according to the present invention are not limited to these.

The microencapsulated latent heat storage material is preferably added as a slurry uniformly dispersed in water. By adding it as a slurry, not only a base material in which the microencapsulated latent heat storage material is uniformly dispersed can be easily obtained, but also due to collision or friction between capsules or between capsules and other particles during kneading / stirring, etc. Capsule damage can be reduced. Further, by supplying the water necessary for the hydration of the hydraulic material from the slurry, the manufacturing facility can be simplified.

The content of the microcapsules in the latent heat storage building material of this embodiment is 1 part by weight or more and 200 parts by weight or more with respect to 100 parts by weight of the mixture of cement and porous inorganic powder.
The range is not more than 10 parts by weight, preferably not less than 10 parts by weight and 1
It is preferably in the range of 50 parts by weight or less.

When the content is more than this range, it is preferable because the latent heat storage property is excellent, but the physical strength of the finished building material is remarkably lowered, and when the content is too small, the heat storage effect described in the present invention becomes poor, which is not preferable. .

The solid content concentration of the microencapsulated latent heat storage material slurry is 5% or more and 70% or less, more preferably 30% or more and 50% or less. If the solid content concentration is too high, it is possible to adjust by adding water, but if the solid content concentration is too low, it is not possible to mix a sufficient amount of heat storage capsules, and whether the function as a heat storage material cannot be fully exerted,
It is not preferable because it adversely affects the hardening of the hydraulic material.

As the hydraulic material used in the present invention, cement or gypsum can be used. As cement, normal, early strength, moderate heat Portland cement, blast furnace,
Mixed cement such as silica and fly ash cement,
And alumina cement and the like. These may be used alone or in combination.

It is sufficient that the gypsum raw material has such a purity that it can be used as a gypsum board raw material. The gypsum used may be any one of α-type hemihydrate gypsum, β-type hemihydrate gypsum, or a mixture thereof, and can be used in an arbitrary mixing ratio.

If the water content required for kneading is insufficient, the fluidity of the kneaded product will be significantly deteriorated, and not only a uniform composition will be difficult to obtain but also molding and construction after kneading will be difficult. It is preferable to add a necessary amount of water to.

Further, it is possible to add various materials which are usually used in the production of board-like building materials such as dispersants and reinforcing fiber materials.

The kneading machine for the compound is not particularly limited, but a twin-screw forced agitation mixer, an Erich mixer, an omni mixer and the like can be used.

As the molding method and the curing method, the methods used in the production of ordinary board building materials can be used.

Example 1 37 g per 6.2 g of melamine powder
% Formaldehyde aqueous solution 12g and water 40g, p
After adjusting H to 8, it was heated to about 70 ° C. to obtain an aqueous melamine formaldehyde initial condensate solution.

8 g of n-octadecane (melting point: 27 ° C.) as a heat storage material was added to 100 g of a 10% styrene-maleic anhydride sodium salt aqueous solution whose pH was adjusted to 4.5.
Part was added with vigorous stirring, and the average particle size was 3.5μ.
The emulsion was emulsified until m.

The whole amount of the above melamine-formaldehyde initial condensate aqueous solution was added to this emulsion, and the mixture was stirred at 70 ° C. for 2 hours, adjusted to pH 9 and dispersed in microcapsules of a heat storage material having a solid content concentration of 45%. A liquid was obtained.

Aluminum powder was added to a mixed slurry containing 65% siliceous raw material and 35% calcareous raw material as main raw materials to foam and harden it, and then hydrothermally treated by high temperature and high pressure steam curing to obtain porous calcium silicate. It was The obtained porous calcium silicate was pulverized to a volume average particle size of 30 μm.

430 g of ordinary Portland cement, 1000 g of the above-mentioned porous calcium silicate powder, and 7 g of vinylon fiber were mixed with a 5 liter omni mixer for 2 minutes, and then 1300 g of the heat storage slurry was added and kneaded for 2 minutes.

The obtained mortar was dehydrated and press-molded by a dehydration press machine using a mold of 300 mm × 400 mm to obtain a plate-shaped molded body having a thickness of about 10 mm. The molded body was steam-cured at 60 ° C. for 12 hours.

The amount of leakage of the latent heat storage material caused by the breakage of the microcapsules by solvent extraction was measured, and the damage state of the capsules was investigated. As a result, it was found that most of the mixed microcapsules were present in the dispersion without being broken. It became clear.

The heat storage board thus obtained has an ambient temperature of 0 ° C. to 5 ° C.
When placed in a 0 ° C temperature change test tank and measured the temperature of the central part of the heat storage board, a buffering property of temperature was observed at around 27 ° C, and a building material with properties that were not easily changed from the temperature around it was obtained. Was given. The rate of change in length of the heat storage board from 24 ° C to 30 ° C was 200 µm / m.

Example 2 A heat storage board was prepared in the same manner as in Example 1 except that diatomaceous earth powder having a volume average particle diameter of 35 μm was used instead of the porous calcium silicate of Example 1. The amount of leakage of the latent heat storage material due to the breakage of the microcapsules by solvent extraction was measured, and the damage state of the capsules was investigated.As a result, it was revealed that most of the mixed microcapsules were inherent in the dispersion without being damaged. It was

The obtained heat storage board was used at an environmental temperature of 0 ° C to 5 ° C.
When placed in a 0 ° C temperature change test tank and measured the temperature of the central part of the heat storage board, a buffering property of temperature was observed at around 27 ° C, and a building material with properties that were not easily changed from the temperature around it was obtained. Was given. The rate of change in length of the heat storage board from 24 ° C to 30 ° C was 210 µm / m.

Example 3 As the porous inorganic powder, pearlite powder crushed to a volume average particle size of 33 μm was used in place of the porous calcium silicate of Example 1 described above, and heat was stored under the same conditions as in Example 1 above. A board was made. As a result of measuring the amount of latent heat storage material leaked due to breakage of the microcapsules by solvent extraction and examining the damage state of the capsules,
It was revealed that most of the mixed microcapsules were inherently dispersed without being damaged.

The obtained heat storage board has an environmental temperature of 0 ° C to 5 ° C.
When placed in a 0 ° C temperature change test tank and measured the temperature of the central part of the heat storage board, a buffering property of temperature was observed at around 27 ° C, and a building material with properties that were not easily changed from the temperature around it was obtained. Was given. The rate of change in length of the heat storage board from 24 ° C to 30 ° C was 220 µm / m.

Comparative Example 1 Ordinary Portland Cement 1
430 g and 7 g of vinylon fiber were mixed in a 5 liter omni mixer for 2 minutes, and the heat storage slurry was mixed with 130 g of the heat storage slurry.
0 g was added and kneaded for 2 minutes.

The obtained mortar was dehydrated and press-molded by a dehydration press machine using a mold of 300 mm × 400 mm to obtain a plate-shaped molded body having a thickness of about 10 mm. The molded body was steam-cured at 60 ° C. for 12 hours. The rate of change in length of the obtained heat storage board from 24 ° C. to 30 ° C. was 1000 μm / m.

[0066]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution and operation, in the latent heat storage building material using the hydraulic composition according to the present invention and in the production thereof, a long temperature near the phase transition temperature of the latent heat storage material is obtained. It is possible to provide a hydraulic composition suitable for the production of a latent heat storage building material, which has a small rate of change in temperature, and in which most of the mixed latent heat storage material microcapsules can be dispersed and contained without being damaged.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 5/08 C04B 111: 40 // C04B 111: 40 C09K 5/00 E (72) Inventor Mamoru Ishiguro Tsukuba City, Ibaraki Prefecture No. 46 Wadai Mitsubishi Paper Mills In-house F-term (reference) 4G012 LA13 PA03 PA05 PA07 PB14 PB16 PB18 PC01 PC11 4G019 LA02 LA04 LB01 LB02 LD02

Claims (2)

[Claims] 1. A hydraulic composition comprising a hydraulic material, microcapsules containing a latent heat storage material, and microcapsules containing a latent heat storage material containing a porous inorganic powder. 2. The hydraulic composition according to claim 1, wherein the hydraulic material is cement or gypsum.