KR100748622B1 - Process of heat insulating board using water glass - Google Patents

Abstract

A method for producing an environment-friendly heat insulating light weight porous board with uniform pores using water glass without a low temperature through control of reaction temperature. A method includes the steps of: mixing sodium silicate comprising 30 to 35 wt% of silicon dioxide(SiO2) and having a viscosity of 600(CP) with calcium phosphate as a catalyst, sodium aluminate(NaAlO2) powder as a pore forming agent, potassium silicate(K2SiO3) aqueous solution comprising 19 wt% of silicon dioxide(SiO2) as a water resistant enhancer and anti-whitening agent in an attrition mill, loading the mixture in a mold, followed by curing at 350 to 500 deg.C. The calcium phosphate is one selected from Ca(H2PO4)2, Ca2(HPO4)2, Ca3(PO4)2 and a mixture thereof and used in an amount of 1 to 2 weight parts based on 100 weight parts of the mixture. The sodium aluminate is used in an amount of 4 to 7 weight parts based on 100 weight parts of the mixture. The potassium silicate(K2SiO3) is used in an amount of 2 to 5 weight parts based on 100 weight parts of the mixture.

Description

Process of manufacturing lightweight porous insulating board using water glass {Process of heat insulating board using water glass}

1 is a photograph of a light weight porous thermal insulation prepared by the present invention

FIG. 2 is a scanning electron micrograph of the insulation surface of FIG. 1. FIG.

FIG. 3 is a microstructure photograph of the insulation surface of FIG. 1 taken by a scanning electron microscope.

The present invention relates to a method for manufacturing a lightweight porous insulating board that can be used as a heat insulating material using water glass, and more specifically, it is environmentally friendly and does not generate toxic gas in case of fire, and is excellent in processability and formed pores. The present invention relates to a method for producing an inorganic light weight porous insulating board having excellent thermal insulation effect.

Conventionally, the inorganic heat insulating material is used in the form of chopped or plated using glass fiber, rock wool fiber, ceramic fiber, etc., glass fiber is often used as a chop, in this case due to the empty space formed between the fibers It is used for cold protection or prevention of heat by preventing heat transfer, and has the effect of energy saving, and it has a soundproofing function. Since 1930, it is most widely used as an insulation in outer wall, ceiling, and underground in the form of filler, roll, and unpacked.

However, in the case of glass fiber, the weight is relatively heavy and there is a problem such that itching occurs when the glass powder generated by cutting or the like is scattered during work in the field and attached to the skin, and the resin used as a binder due to aging after construction When the resin is decomposed, the resin powder and the decomposed glass powder are scattered, which acts as a pollutant for the surrounding environment, and the International Cancer Research Center (IARC) classifies glass fibers as carcinogens. It is becoming an obstacle.

In addition, ceramic fibers used as high-temperature insulation materials are manufactured in the form of plates using a binder in the case of rock wool, or used in the state of rock wool fabric and nonwoven fabric, but in this case, it causes environmental pollution scattered from aged asbestos fibers. Substances are the cause of cancer eventually, and in order to be free from these problems, the improvement of the processing process is being made, but as the increase of the process, the processing cost increases, and the original functions disappear. .

Due to the problems described above, the use of an insulating material made of inorganic fibers such as glass fiber, asbestos fiber or ceramic fiber is avoided. In order to replace this, water glass is used as a main material and foamed to form a foam. There is a continuing research on a heat insulator.

Conventional techniques in this field may include, for example, Korean Laid-Open Patent Publication No. 2003-0075259, Korean Laid-Open Patent Publication No. 2004-0101708, and the like.

Korean Unexamined Patent Publication No. 2003-0075259 discloses a technique of kneading mineral particles mainly composed of sodium silicate and silica with water, followed by heating to 120 ° C to 500 ° C, and foaming by such a method. Manufactured foam has a higher strength than ordinary gypsum board and maintains light weight with a specific gravity of 0.2 to 0.4. However, the insulation produced by such a method excessively whitens when used for a long time. Some problems may arise.

In addition, Korean Laid-Open Patent Publication No. 2004-0101708 mixes aluminum hydroxide slurry and water glass, prepares beads in the state of silica gel using sulfuric acid and aluminum sulfate, and then fires and foams them at a high temperature of 700 ° C to 1200 ° C. Although the technology is known, this method requires high temperature heat for its own molding, which leads to a high input of energy, resulting in high production costs, and insufficiency of the spherical interface due to fusion caused by high temperature. In addition, since the mechanical strength is lowered, it is difficult to mold by the binder.

The present invention for solving the above problems is to develop a core technology for manufacturing expensive insulation boards that can form uniform pores and environmentally friendly, energy saving without using a binder using a low-cost raw material Its purpose is to promote the dehydration condensation reaction using water glass as a raw material to form a three-dimensional network structure to form a network of Si-O-Si, and to form pores and at the same time low temperature by controlling the reaction temperature. In order to provide a method for manufacturing a lightweight porous insulating board by using a molding technology without adhesive.

The present invention for solving the above problems is calcium phosphate and sodium aluminate (NaAlO ₂ ) in water silicate (silicon dioxide) having a silicon dioxide (SiO ₂ ) content of 30% to 35% by weight and a viscosity of 600CP (20 ℃) Powder and silicon dioxide (SiO ₂ ) content of 19% by weight of potassium silicate (K ₂ SiO ₃ ) aqueous solution was added and thoroughly mixed with an attrition mill, and then the prepared mixture was charged to a mold and 350 to It can be achieved by providing a method of manufacturing a lightweight porous insulating board using water glass characterized in that the foam hardening at 500 ℃.

Generally, water glass is obtained by melting and treating a mixture of silica sand and sodium carbonate at 1,300 ° C. to 1,500 ° C., and forms various compounds of Na ₂ SiO ₃ , Na ₆ Si ₂ O ₇ , and Na ₂ Si ₃ O ₇ depending on the mixing ratio. In order to achieve proper foaming and curing, it is preferable that the content of silicon dioxide (SiO ₂ ) is 30% by weight to 35% by weight, and the viscosity is 600 CP ( 20 ° C.).

In the above, calcium phosphate is added as a condensation reaction accelerator, such as monobasic calcium phosphate (Ca (H ₂ PO ₄ ) ₂ ), dibasic calcium phosphate (Ca ₂ (HPO ₄ ) ₂ ), tertiary calcium phosphate (Ca ₃ (PO ₄ ) Any one of ₂ ) may be used, and a mixture thereof may be used, and the amount of the mixture is added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the whole mixture.

Calcium phosphate added as a catalyst 1 Parts by weight When added below, foaming is insufficient and the unit weight of the manufactured heat insulating agent becomes heavy, and when it is added 2 parts by weight or more, there is a problem that causes cracking distortion in the heat insulating material produced after curing even at a low curing temperature. Will be.

Sodium aluminate (NaAlO ₂ ) is added to promote the pore formation and improve the strength of the insulation to be produced, 4 parts by weight to 7 parts by weight with respect to 100 parts by weight of the mixture for preparing the insulation Preferably added, 4 When added by weight, the strength of the prepared heat insulating agent is weakened, and due to the weakness, it is inconvenient to take considerable care when constructing or transporting. When added by 7 parts by weight or more, the strength of the prepared heat insulating material is strong. Although it acts advantageously for construction transport and the like, the foaming ratio becomes small, the unit weight becomes heavy, and the problem of deterioration of heat insulation is accompanied.

Potassium silicate (K ₂ SiO ₃ ) is added for the purpose of improving the water resistance and prevention of whitening phenomenon is preferably added to 2 to 5 parts by weight based on 100 parts by weight of the mixture for the production of a heat insulating agent, 2 When added in less than a weight part, the whitening phenomenon due to contact with moisture of the manufactured heat insulating agent cannot be prevented, and when added in an amount of 5 parts by weight or more, the whitening phenomenon can be prevented, but the impact strength is lowered. Done.

In the present invention, in mixing the water glass and the additives, the mixing of water glass and potassium silicate with significant viscosity, calcium phosphate as a liquid catalyst, and powdered sodium aluminate should be mixed. Since it is not possible, a method of separating the mixture by friction using an attrition mill should be used. The mixing time is preferably in the range of 1 hour to 3 hours, and sufficient mixing is not possible within 1 hour. The insulation board is not homogeneous, and if it is mixed for 3 hours or more, the homogeneity can be guaranteed, but it becomes difficult to maintain homogeneous foam pores as the cohesiveness is weakened by the heat generated during the mixing process.

Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

<Example 1>

Commercially available silicon dioxide (SiO ₂ ) content of 31 wt%, 135 g of sodium silicate with a viscosity of 600 CP (20 ° C.), 4.5 g of calcium phosphate, 3.0 g of sodium aluminate (NaAlO ₂ ) powder, and silicon dioxide 7.5 g of potassium silicate (K ₂ SiO ₃ ) solution containing 19 wt% (SiO ₂ ) was added thereto and mixed with an attrition mill for 3 hours, and the resulting mixture was prepared with a diameter of 52.5 mm and a height of 60 mm. Put into each of the six molds, and then charged into the furnace and proceed to cure while increasing the temperature from room temperature to the temperature shown in Table 1 at a rate of 10 ℃ / min to prepare a foam insulation to expand the foaming ratio of the volume to weight The change ratio was measured, and the compressive strength was measured using the model H10K of Tinus toolsen of the United States, and the results are shown in Table 1 together.

Curing temperature (℃) Compressive strength (㎏f / ㎠) Expansion ratio Remarks 300 180 6 Foam deficiency 350 140 45 400 128 50 450 107 65 500 98 70 550 60 75 Under-strength, Pore Unevenness

As confirmed from Table 1, it was confirmed that the compressive strength and the foaming ratio have an inverse proportional relationship, and the heat insulating material consisting of the mixing ratio of the range of the present invention was markedly 6 at the foaming ratio of 300 ° C at a low temperature. It can be confirmed that the foam is in a poor state of foaming, and at 550 ° C, foaming magnification shows a considerably high foaming magnification, but the pores become uneven and the compressive strength falls significantly below the lower limit of 80 kgf / ㎠. Could confirm.

<Examples 2 to 8>

Water glass, calcium phosphate, potassium silicate and sodium aluminate were mixed with an attrition mill for 1 hour at a ratio as shown in Table 2 below, and the prepared mixture was prepared with a mold having a diameter of 52.5 mm and a height of 60 mm. Put each into a dog, and then charged into a furnace, the temperature is raised from the room temperature to a temperature shown in Table 2 below at a rate of 10 ℃ / min to proceed with curing to prepare a foam insulation to convert the expansion ratio of the volume to weight ratio In addition, the compressive strength was measured using the model H10K of Tinus toolsen of the United States, and the results are shown in Table 2 together.

Example Water glass (g) Calcium phosphate (g) Potassium Silicate (g) Sodium aluminate (g) Curing temperature (℃) Compressive strength (㎏f / ㎠) Expansion ratio Remarks 2 135 1.5 7.5 6.0 350 145 35 400 110 40 450 113 45 500 95 58 3 1.5 6.0 7.5 350 145 35 400 109 40 450 105 45 500 95 50 4 1.5 4.5 9.0 350 150 35 400 115 35 450 120 45 500 108 45 5 1.5 3.0 10.5 350 148 35 400 112 35 450 100 40 500 110 45 6 4.5 9.0 1.5 350 92 40 400 80 50 450 76 65 500 65 70 Pore Unevenness 7 6.0 7.5 1.5 350 60 40 400 50 70 Pore Unevenness 450 42 70 Pore Unevenness 500 40 75 Pore Unevenness 8 7.5 6.0 1.5 350 50 40 400 43 75 Pore Unevenness 450 38 75 Pore Unevenness 500 36 80 Pore Unevenness

As can be seen from Table 2 above, in the temperature range of the present invention, the results of experiments varying only the mixing ratio of calcium phosphate, potassium silicate, sodium aluminate and water glass, and Examples 2 to 5 corresponding to the scope of the present invention. In the case of foaming magnification of 35 or more, but the compressive strength of 95kgf / ㎠ to 145kgf / ㎠ shows a case of Examples 6 to 8 carried out outside the scope of the present invention Example 6 In the case of cure temperature of 400 ℃, the lower limit of compressive strength is 80kgf / cm2, and when temperature rises, the compressive strength is less than the lower limit, and the pores become uneven. You can see that occurs.

In addition, in the case of Examples 7 and 8, at any curing temperature of the temperature range of the present invention, a heat insulating material showing a compressive strength above the lower limit value could not be obtained. Questions have been raised about whether insulation can be guaranteed.

As described above, the heat insulating material manufactured by the manufacturing method of the present invention has sufficient heat insulating property by uniform porosity as shown in FIG. 2, and the loss due to breakage during construction and transportation by excellent compressive strength. It is a useful invention that can be prevented.

Claims (4)

In the method of manufacturing a porous insulating board using water glass, calcium phosphate and pores as catalysts on sodium silicate having a silicon dioxide (SiO ₂ ) content of 30% to 35% by weight and a viscosity of 600CP (20 ° C). Sodium aluminate (NaAlO ₂ ) powder as a formation promoter and an aqueous potassium potassium silicate (K ₂ SiO ₃ ) solution containing 19% by weight of silicon dioxide (SiO ₂ ) as an anti-whitening agent is added to the attrition mill After mixing sufficiently, the mixture is charged into a mold and foamed and cured at 350 ° C to 500 ° C. The method according to claim 1, wherein the calcium phosphate added as a catalyst is the first calcium phosphate (Ca (H ₂ PO ₄ ) ₂ ), dicalcium phosphate (Ca ₂ (HPO ₄ ) ₂ ), tricalcium phosphate (Ca ₃ (PO ₄ ) Method for producing a lightweight porous insulating board using water glass, characterized in that 1 to 2 parts by weight based on 100 parts by weight of the mixture is added or manufactured alone or mixed selected from ₂ ) The light weight porosity using water glass according to claim 1 or 2, wherein sodium aluminate added as a promoter for pore formation is added so as to be 4 parts by weight to 7 parts by weight with respect to 100 parts by weight of the mixture for preparing the heat insulating agent. Manufacturing Method of Insulation Board The light weight using water glass according to claim 3, wherein the potassium silicate (K ₂ SiO ₃ ) added as an agent for improving water resistance and anti-whitening is 2 parts by weight to 5 parts by weight with respect to 100 parts by weight of the mixture for preparing the insulation. Manufacturing method of porous insulation board

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