KR100857594B1 - Process of heat insulating board using water glass - Google Patents

Abstract

A porous light insulating board is provided to obtain sufficient insulation and excellent compressive strength by forming homogeneous porous with water glass in the board. A porous light insulating board is prepared by: mixing water glass comprising 30-35% by weight of silicon dioxide, calcium phosphate as a catalyst, sodium aluminate as a pore-forming enhancer, and potassium silicate as a water-resistance improvement and anti-chalking agent; putting the mixture in a mold; and foaming and curing the mixture at 350-500deg.C. The calcium phosphate is at least one selected from calcium phosphate monobasic, calcium phosphate dibasic, calcium phosphate tribasic and mixtures thereof, and the amount of the calcium phosphate is 1-2 parts by weight with respect to 100 parts by weight of the mixture. The amount of the sodium aluminate is 4-7 parts by weight, and the amount of the potassium silicate is 2-5 parts by weight, with respect to 100 parts by weight of the mixture. Further, the light insulating board is used as Interior and exterior decorative composition for construction.

Description

Light weight porous board made of water glass {Process of heat insulating board using water glass}

1 is a photograph of a lightweight porous thermal insulation prepared by the present invention,

FIG. 2 is a scanning electron micrograph of the surface of the thermal insulator of FIG. 1;

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

The present invention relates to a method of 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 workability and formed by excellent pores. The present invention relates to a method for producing an inorganic porous lightweight board having an insulating effect.

Conventionally, inorganic insulating materials are used in the form of bolts or platelets using glass fibers, rock wool fibers, ceramic fibers, etc., and glass fibers are often used as bolts, and in this case, due to the void space formed between the fibers, As it is used for cold protection or anti-air protection by preventing heat transfer, it not only has the effect of saving energy, but also has the function of sound insulation. Since 1930, fillers, rolls, and unpacked forms have been most widely used as insulation on outer walls, ceilings, and basements.

However, in the case of glass fiber, the weight is relatively heavy, and when it is adhered to the skin due to the scattering of glass powder generated by cutting in the field, itching causes itching, and it is used as a binder due to aging even after construction. When the resin is decomposed, the resin powder and the decomposed glass powder are scattered, which acts as a pollutant to the surrounding environment, and the International Cancer Research Center (IARC) classifies glass fibers as carcinogens. It is an obstacle to extended use.

In the case of rock wool, ceramic fiber used as a high-temperature insulation material is manufactured in the form of a plate using a binder, or used in the state of rock wool fabric and nonwoven fabric, but in this case, environmental pollution scattered from aged asbestos fiber is also used. The causative agent eventually causes cancer and improves the processing process in order to be free from such problems. However, the processing cost increases with the increase of the process, and the original function disappears. .

Due to the above problems, the use of heat-insulating materials made of non-substrate 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. The research on the processed insulation is continuing.

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 together with water, followed by heating to 120 ° C. to 500 ° C., and manufactured by the same method. The foam has a higher strength than the general gypsum board and has a specific gravity of 0.2 to 0.4. However, the foam has a problem of causing excessive whitening when used for a long time. Occurs.

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 them at a high temperature of 700 ° C. to 1200 ° C. to foam. 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 higher 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.

In order to solve the problems as described above, the present invention is to develop a core technology for manufacturing a thermal insulation board that can realize uniform pores and environmentally friendly, energy saving without the use of a binder using a low-cost raw material Water glass as a raw material to promote the dehydration condensation reaction to form a three-dimensional network structure forming a network of Si-O-Si to form pores and at the same time control the reaction temperature without adhesive It is to provide a lightweight porous insulating board using a molding technology.

In order to solve the above problems, the present invention is a water glass having a silicon dioxide content of 30 to 35% by weight, calcium phosphate as a catalyst, sodium aluminate as a pore-forming accelerator and potassium silicate as a water resistance improving and anti-whitening agent, and then mixed It is charged to a mold and foamed and cured at 350 to 500 ° C. to prepare a porous lightweight board using water glass.

That is, calcium phosphate, sodium aluminate (NaAlO ₂ ) powder and silicon dioxide (SiO ₂ ) in a water silicate containing 30 wt% to 35 wt% of silicon dioxide (SiO ₂ ) and a viscosity of 600 CP (20 ° C.). After adding 19% by weight aqueous potassium silicate (KaSiO ₃ ) solution, the mixture was thoroughly mixed with an attrition mill, and then the prepared mixture was charged into a mold and foamed and cured at 350 ° C. An example of the lightweight porous heat insulating material of the present invention manufactured as described above is shown in FIG. 1, FIG. 2 is a scanning electron micrograph of the surface of the heat insulating material of FIG. 1, and FIG. 3 is a scanning electron micrograph of a fracture surface of the heat insulating material. Microstructure picture taken under a microscope.

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

In the above, calcium phosphate is added as a condensation reaction accelerator, and the first calcium phosphate (Ca (H ₂ PO ₄ ) ₂ ), the second calcium phosphate (Ca ₂ (H ₂ PO ₄ ) ₂ ), the third calcium phosphate (Ca ₃ Any one of (H ₂ PO ₄ ) ₂ ) may be used, and a mixture thereof may be used, and the amount of the mixture is added so as to be 1 to 2 parts by weight when the entire mixture is 100 parts by weight.

When the calcium phosphate added as a catalyst is added in an amount of 1 part by weight or less, the foaming is inadequate, resulting in a heavy unit weight of the manufactured insulation, and when added in an amount of 2 parts by weight or more, the insulation is prepared after curing although it is cured at a low curing temperature. There is a problem that causes cracks in the warp.

Sodium aluminate (NaAlO ₂ ) is added to promote the pore formation of the heat insulating material and to improve the strength, it is preferable to add 4 parts by weight to 7 parts by weight with respect to 100 parts by weight of the mixture for producing the heat insulating material, If the amount is less than 4 parts by weight, the strength of the prepared heat insulating material is weakened due to the weakness of the construction or transportation due to the inconvenience that must be taken, and if more than 7 parts by weight of the prepared heat insulating material becomes stronger Although advantageously for construction transportation and the like, the foaming ratio becomes small, the unit weight becomes heavy, and the problem of lowering the thermal insulation is accompanied.

Potassium silicate (KaSiO ₃ ) is added for the purpose of improving water resistance and preventing whitening, and is preferably added in an amount of 2 parts by weight to 5 parts by weight based on 100 parts by weight of the mixture for preparing the heat insulating material, and is added in an amount of less than 2 parts by weight. In this case, the whitening phenomenon may not be prevented due to contact with moisture of the manufactured insulation, and when added in an amount of 5 parts by weight or more, the whitening phenomenon may be prevented, but the impact strength may be lowered.

In the present invention, in mixing water glass and additives, it is necessary to mix water glass and potassium silicate having significant viscosity, calcium phosphate as a liquid catalyst, and powdered sodium aluminate. Therefore, the method of mixing 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. If it is mixed for more than 3 hours, homogeneity can be guaranteed, but it becomes difficult to maintain homogeneous foam pores as caking is weakened by 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, followed by mixing for 3 hours using an attrition mill, and then the prepared 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 raising the temperature from room temperature to the temperature shown in Table 1 at a rate of 10 ℃ / min to prepare a foam insulation to change the expansion ratio of the volume to weight The compressive strength was measured using a model H10K of Tinus toolsen of the United States of America, and the results are shown in Table 1 together.

Curing temperature (℃) Compressive strength (kgf / cm ² ) Expansion ratio Remarks 300 180 6 Foam deficiency 350 140 45 400 128 50 450 107 65 500 98 70 550 60 75 Understrength, pore unevenness

As confirmed from Table 1, it could be 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 at 300 ° C. It can be confirmed that the foam is not satisfactorily foamed. At 550 ° C, foaming magnification shows a considerably high foaming magnification, but the pores become uneven and the compressive strength of the lower limit is 80kgf / cm ^2. It was found that the phenomenon falling significantly less.

< Example  2 to 8>

Water glass, calcium phosphate, potassium silicate and aluminate natrium 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 a 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 (kgf / cm ² ) 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 confirmed from Table 2 above, in the temperature range of the present invention, the results of experiments varying only the mixing ratio of calcium phosphate, calcium silicate and sodium aluminate and water glass, Examples 2 to Examples falling within the scope of the present invention. In case 5, the foaming ratio is 35 or more and the compressive strength is 95kgf / cm ² To 145kgf / cm ² , but in the case of Examples 6 to 8 carried out outside the scope of the present invention, in the case of Example 6 when the curing temperature is 400 ℃ 80kgf / cm ^{2 which is the} lower limit of the compressive strength In the case where the temperature rises, the compressive strength not only falls below the lower limit, but also the problem of uneven pores occurs.

In addition, in the case of Example 7 and Example 8, at any curing temperature of the temperature range of the present invention, a heat insulating material showing a compressive strength of more than the lower limit could not be obtained. The question was raised whether insulation could 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 (6)

As a porous lightweight board based on water glass, Water glass with a silicon dioxide content of 30 to 35% by weight, calcium phosphate as a catalyst, sodium aluminate as a pore-forming accelerator and potassium silicate as a water-resistant and anti-whitening agent, and then charged into a mold and foamed at 350 ~ 500 ℃ Porous lightweight board made of water glass, characterized in that the hardened and manufactured. The method of claim 1, The calcium phosphate is a single or mixed mixture selected from the first calcium phosphate, the second calcium phosphate and the third calcium phosphate, the porous lightweight board made of water glass, characterized in that 1 to 2 parts by weight based on 100 parts by weight of the mixture . The method of claim 1, The sodium aluminate is a porous lightweight board based on water glass, characterized in that 4 to 7 parts by weight based on 100 parts by weight of the mixture. The method of claim 1, The potassium silicate is a porous lightweight board based on water glass, characterized in that 2 to 5 parts by weight based on 100 parts by weight of the mixture. The method according to any one of claims 1 to 4, The lightweight board is a porous lightweight board made of water glass, characterized in that used as interior and exterior materials for building. The method according to any one of claims 1 to 4, The lightweight board is a porous lightweight board made of water glass, characterized in that used as a non-bearing heat insulation wall or soundproof wall.

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