KR20170002763A - Waterproof board showing good crack resistance and method for preparing the same - Google Patents

Abstract

The present invention relates to a waterproof board showing excellent crack resistance and a manufacturing method thereof, and more specifically, to a waterproof board comprising a cured product of an aqueous gypsum slurry containing hemihydrate gypsum, silicone oil, and a specific catalyst and showing excellent crack resistance and a low total absorption rate, and a manufacturing method thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a waterproof board having excellent crack resistance,

The present invention relates to a waterproof board exhibiting excellent crack resistance and a method of manufacturing the same. More particularly, the present invention relates to a waterproof board comprising a cured product of an aqueous gypsum slurry containing a semi-gypsum, a silicone oil and a specific catalyst, And a method of manufacturing the waterproof board.

The gypsum board, which is a non-combustible and light-weight material with excellent car sound, is widely used as a building interior material due to its low price. The raw material of general gypsum board for construction is semi-gypsum, which is obtained by firing natural high-grade or desulfurized lime stone and removing crystal water. Half-gypsum is converted into an algebraic structure with a crystal structure, which is heated when reacted with water. During this process, the well-developed crystal structure of the needle-shaped bed increases the strength of the gypsum board itself and produces a gypsum board wrapped with a covering material by closely engaging with the gypsum board fiber.

In order to improve the productivity, various additives are also put in order to produce a gypsum board having various functions. For example, the foaming agent is an essential additive for forming gypsum board pores to lighten the gypsum board. As the foaming agent, a surfactant which mainly provides pores in the gypsum board is used. The gypsum board is a material that is weak to moisture, but it can also be used on the wall of a shower room by giving it a waterproof function. As a waterproofing agent, silicone, asphalt or paraffin wax is generally used. However, asphalt has an advantage in that it is inexpensive, but it has a disadvantage in that it can only produce a black solid color. In case of paraffin wax, it is made water-soluble by using emulsifier and added to the gypsum board manufacturing process. Since paraffin wax covers the surface of gypsum and exhibits waterproof effect, it needs to use a lot of paraffin. Quot;

In the case of paraffin wax dispersed in an aqueous solution, it is mixed and dispersed in the slurry during the process of producing gypsum slurry. The dispersed paraffin wax is pushed to the gypsum surface as the semi-gypsum slurry grows into an asteroid solid. As the paraffin wax is dispersed evenly on the surface of the gypsum, the water repellency effect increases. However, since the paraffin wax does not form a strong bond with the gypsum surface, as the process water in the center of the board moves to the surface during drying of the gypsum board, It is difficult to spread them evenly on the surface of the gypsum. Therefore, a relatively large amount of paraffin wax is required to provide an effective waterproofing function. If there is a thermal change in the gypsum board at a later time, the paraffin wax moves to one side or is eluted by organic matter, .

When a silicone compound is used as a waterproofing agent, the hydrogene functional group of the silicone oil is hydrolyzed into a hydroxyl functional group during the production of the gypsum slurry, and this functional group is hydrolyzed by reacting with the hydroxyl functional group, Is fixed to the solid body. Through this process, the silicone oil is chemically bonded to the surface of the gypsum so as to cover the surface of the gypsum, and the water-repellent methyl group is positioned perpendicular to the surface of the gypsum, thereby exhibiting an effective water-repellent function on the surface of the gypsum. However, the silicone oil has a strong defoaming property and thus has a problem of removing bubbles generated in the gypsum core by using a foaming agent.

There is a patent (for example, US Patent Application Publication No. 2006/0162839 A1) disclosing a chemical stabilization method for enhancing the stability of a foam by adding an organic stabilizer to a surfactant, It is suitable for the purpose of avoiding vesicular action or suppressing the defoaming by hydrocarbons of paraffin waxes. However, it is difficult to apply the silicone-based waterproofing agent because of its large defoaming property. In recent years, a physical solution (for example, European Patent EP 1 637 302 A1) such as a facility improvement has been disclosed, but the above problems can not be solved.

It is an object of the present invention to provide a waterproof board exhibiting excellent crack resistance and a low water absorption rate and a method of manufacturing the same.

The waterproof board of the present invention comprises a cured product of a water-based gypsum slurry containing a semi-gypsum, a silicone oil, and a carbonate rock mineral as a catalyst.

The waterproof board manufacturing method of the present invention includes forming an aqueous gypsum slurry containing a semi-gypsum, a silicone oil, and a carbonate rock mineral as a catalyst, and curing the slurry.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a waterproof board exhibiting excellent crack resistance and low total water absorption while using a small amount of silicone oil compared to paraffin wax.

Hereinafter, the present invention will be described in detail.

The waterproof board provided in the present invention comprises a cured product of water-based gypsum slurry containing semi-gypsum, silicone oil, and light dolomite as catalyst. The cured product of the gypsum slurry can be used as the core of the board.

The semi-gypsum gypsum is obtained by calcining a natural alumite or desulfurization alumite to remove a part of the crystal water.

In the waterproof board of the present invention, the gypsum content in the gypsum slurry may be, for example, 40 to 80% by weight, more specifically 50 to 70% by weight, based on 100% by weight of the slurry. In addition, the water content in the gypsum slurry of the present invention may be, for example, 20 to 60 wt%, more specifically 30 to 50 wt%, based on 100 wt% of the slurry.

The silicone oil may be a linear or cyclic, at least partially hydrogen-modified polysiloxane, which is used for imparting a water-proofing function. Such polysiloxanes can be polymerized in a basic environment to form highly crosslinked siloxane polymers, which polymers exhibit high water resistance. More specifically, the polysiloxane may include a structure represented by the following formula.

In the above structural formula, R ₁ is independently a hydrogen or non-hydrogen substituents (e.g., unsubstituted or substituted by halogen, alkyl, cycloalkyl, aryl or heteroaryl), provided that a plurality of R ₁ , More specifically at least 10% (e.g., 10 to 100%) is hydrogen; R ₂ is a non-hydrogen substituent as described above; n is an integer from 1 to 200;

In the above, for example, the number of carbon atoms of alkyl may be 1 to 4, the number of carbon atoms of cycloalkyl may be 5 to 10, the number of carbon atoms of aryl may be 6 to 12, and the total number of ring atoms of heteroaryl may be 5 to 12 And may also have at least one heteroatom selected from N, O and S. The halogen may be fluorine, chlorine, bromine or iodine.

More specifically, the polysiloxane may comprise a structure represented by the following formula.

In the above structural formulas, x and y are mole fractions of the structural units to which they respectively indicate x + y = 1, x is 0.1 to 1, and y is 0 to 0.9.

According to a preferred embodiment of the present invention, a silicone oil containing methylhydrogenpolysiloxane (MHP) is used as the silicone oil.

In the waterproof board of the present invention, the silicone oil content in the gypsum slurry may be, for example, 0.04 to 4 parts by weight, more specifically 0.1 to 1.5 parts by weight, based on 100 parts by weight of the semi-gypsum. If the content of the silicone oil in the gypsum slurry is less than the above range, the target waterproofing property may not be exhibited. On the other hand, if it is too much, the amount of the gypsum used increases due to the peculiar defoaming property of the silicone oil, There may be a problem of hardening inside the mixer.

In the present invention, the silicone oil may be added to the board manufacturing process itself, or alternatively may be emulsion or water dispersion emulsified in water using a surfactant and / or a high shear rotary reactor or a high pressure homogenizer, It may be added to the process.

The silicone oil applied as a waterproofing agent to the gypsum board is usually hydrolyzed under basic conditions of an alkali metal or alkaline earth metal oxide or hydroxide base catalyst (a basic catalyst in aqueous solution) to convert the linear polysiloxane to a branched polysiloxane Thereby imparting waterproof performance.

However, when the basic catalyst is used, the pH may rise to slow the hydration process of the semi-gypsum. Silicone oil may break down the bubbles generated in the gypsum board slurry due to low surface tension and hydrogen gas generated as a byproduct during the hydrolysis reaction It may be difficult to lighten the gypsum board or cause cracks in the gypsum board core.

Therefore, in the present invention, by using a catalyst of a carbonate mineral component specifically, without using the conventional cement, CaO, calcined dolomite, Ca (OH) ₂ , NaOH and the like in the production of a waterproof board, Respectively.

Carbonate rock minerals used as the catalyst of the present invention include aragonite, calcite, dolomite and the like, but it is not limited thereto, and preferably, light-weight dolomite can be used.

Light-weight dolomite has a higher catalytic activity than such conventional catalysts, such as small (calcined at 1700 to 1800 ° C) or small (calcined at 1000 to 1500 ° C), while suppressing abrupt catalytic activity, Cracks in the gypsum board are prevented from occurring and the hydration reaction time of the semi-gypsum is not slowed down. Also, it has an advantage that it is easy to apply to a gypsum production process without side reaction with additives added for gypsum board production. Particularly, PNS (poly-naphthalene sulfonate) type fluidizing agent used for lowering the amount of water used in molding gypsum has a problem of increasing the density of the gypsum and reducing the size of the bubble when used together with the siloxane. Lowering the content of siloxane can minimize the problem of vesicles.

The light dolomite is calcined dolomite (dolomite) at a temperature of, for example, 700 to 1000 ° C, and its composition is generally as follows.

In the waterproof board of the present invention, the content of the carbonate rock mineral catalyst in the gypsum slurry may be, for example, 0.2 to 1.5 parts by weight, more specifically 0.3 to 1.0 parts by weight, based on 100 parts by weight of the semi-gypsum. If the catalyst content in the gypsum slurry is less than the above range, the silicone oil may not be polymerized to exhibit sufficient water resistance. On the contrary, there may be a problem that the pH of the whole slurry is increased and the strength is weakened.

Although not particularly limited, the carbonate ore mineral catalyst used in the present invention may have an average particle size of 50 to 4000 탆, preferably 500 to 2500 탆. If the average particle size of the mineral catalyst is excessively small, it is difficult to transfer to the process or accurate quantification becomes difficult. If the average particle size is larger than 4000 탆, the particle size is excessively larger than the particle size of the semi-gypsum raw material, There is a problem that the product becomes heterogeneous.

Further, within the range in which the object of the present invention can be achieved, the gypsum slurry may further include a basic catalyst other than the carbonate rock mineral catalyst. Further usable basic catalysts include limestone, slaked lime, cement, MgO, CaO, CaMgO and the like, which can be used alone or in combination.

The gypsum slurry may further comprise a surfactant. The surfactant includes, for example, an anionic surfactant (such as an anionic surfactant containing a sulfate group), a nonionic surfactant, an amphoteric surfactant (for example, betaine), an alkylpolyglucoside, an alkyl alcohol (For example, C8 to C20 alkyl alcohol), and the like may be used alone or in combination, but the present invention is not limited thereto. PNS (poly-naphthalene sulfonate) fluidizing system can be used as a surfactant.

When the surfactant is contained in the gypsum slurry, the content thereof may be, for example, 2 to 60 parts by weight, more specifically 5 to 40 parts by weight, based on 100 parts by weight of the silicone oil. If the content of the surfactant is too small, the effect of using the surfactant may be insufficient. On the other hand, if the surfactant content is too large, the viscosity of the gypsum slurry may increase and the fluidity may be decreased.

According to another specific aspect of the present invention, there is provided a method for manufacturing a waterproof board, comprising forming a water-based gypsum slurry containing a semi-gypsum, silicone oil, and carbonate rock mineral as a catalyst, and curing the slurry.

According to one embodiment of the present invention, the waterproof board of the present invention is formed by forming a water-based gypsum slurry including a silicone oil or an aqueous emulsion or an aqueous dispersion thereof, a carbonate rock mineral catalyst and a semi-gypsum, And molding and curing the gypsum slurry.

Generally, for the production of a lightweight gypsum board having pores, pre-foam is prepared by injecting high-pressure air into an aqueous solution containing an anionic surfactant, mixed with semi-gypsum and metered process water, Processing. In the case of a light gypsum board, a proper combination of large pores and small pores is required because large pores are mainly formed at the center of the gypsum board and small pores are mainly located at the upper and lower surfaces of the gypsum board, Hardness and drying conditions. Therefore, it is important to maintain adequately large bubbles.

On the other hand, silicone oil acts as a defoaming agent to break the air bubbles in the gypsum slurry and increase the density of the gypsum. In order to compensate for the reduction of bubbles caused by silicon, when the lightweight agent is added in an excessive amount, the size of the bubbles becomes small and the viscosity of the slurry increases, so that it is difficult to form the gypsum board. In addition, when the conventional basic catalyst is used, the reaction rate is too fast, so cracks (cracking) may occur in the gypsum product due to the rapid generation of hydrogen molecules as reaction byproducts.

In the present invention, by using silicone oil as a waterproofing agent, excellent waterproof performance is obtained even by using a small amount of waterproofing agent compared to paraffin wax, and by using a carbonate rock mineral as a catalyst, an appropriate reaction rate can be exhibited to prevent cracking of the gypsum board .

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

[ Example ]

Example One

A gypsum slurry was prepared by mixing 150 g of semi-gypsum, 0.6 g of methylhydrogenpolysiloxane (MHP), 0.6 g of the catalyst described in Table 1 (Comparative Example 1-2 catalyst was not used) and 97.5 g of distilled water. At this time, 0.5 part by weight of PNS as a fluidizing agent and 0.01 part by weight of a retarder (Retarder L) were further contained in the gypsum slurry in comparison with 100 parts by weight of semi-gypsum. The prepared slurry was cured to prepare a gypsum specimen. In Comparative Example 1-1, a gypsum specimen was prepared without using a catalyst and using paraffin wax instead of MHP as a waterproofing agent in an amount of 3.5 parts by weight per 100 parts by weight of the gypsum used.

For the prepared specimens, the total absorbency after drying according to KS F 3504 was measured (weight increase rate of specimen after 100% of original specimen weight), and the presence of cracks in gypsum was confirmed and shown in Table 1.

From the results shown in the above Table 1, it can be seen that the case of using light-weight dolomite as the catalyst provides an excellent total absorptivity (i.e., excellent catalytic activity and waterproofing performance) as compared with the case where no catalyst is used or another catalyst is used .

Example 2

The gypsum specimen of Example 2-1 was prepared in the same manner as in Example 1 except that the amounts of MHP and light dolomite catalyst were 0.5 parts by weight per 100 parts by weight of the gypsum used.

On the other hand, instead of directly using MHP, a gypsum specimen of Example 2-2 was prepared using an emulsion having an MHP content of 40% by weight, which was prepared by passing a mixture of 300 g of distilled water and 200 g of MHP in a high pressure homogenizer at 450 bar. At this time, the amount of MHP and light dolomite catalyst used per 100 parts by weight of the amount of the gypsum used was 0.5 parts by weight each, as in Example 2-1.

In Comparative Example 2, a catalyst was not used, and instead of MHP as a waterproofing agent, paraffin wax was used in an amount of 3.5 parts by weight per 100 parts by weight of a semi-gypsum used amount to prepare a gypsum specimen.

The prepared specimens were dried in the same manner as in Example 1, and then the total absorbency was measured. The presence or absence of cracks in the gypsum was confirmed, and the results are shown in Table 2.

From the results shown in Table 2, it can be seen that both the case of directly injecting MHP and the case of injecting the emulsion with MHP provide an excellent total absorption rate as compared with paraffin wax, and do not generate cracks.

Example 3

A gypsum specimen was prepared using an emulsion having an MHP content of 40% by weight prepared in the same manner as in Example 2-2, except that the surfactant shown in Table 3 below was used in an amount of 3 parts by weight per 100 parts by weight of MHP. The prepared specimens were dried in the same manner as in Example 1, and the total absorbency was measured and shown in Table 3.

Claims (8)

A waterproofing board comprising a cured slurry of water-based gypsum slurry containing semi-gypsum, silicone oil, and carbonate rock minerals as catalyst. The waterproofing board of claim 1, wherein the silicone oil comprises a polysiloxane comprising a structure represented by the formula:

In the above formula, R ₁ is independently hydrogen or a non-hydrogen substituent, and a plurality of R ₁ Lt; / RTI > is hydrogen; R ₂ is a non-hydrogen substituent; n is an integer from 1 to 200; The waterproofing board according to claim 2, wherein the polysiloxane comprises a structure represented by the following formula:

In the above structural formulas, x and y are mole fractions of the structural units to which they respectively indicate x + y = 1, x is 0.1 to 1, and y is 0 to 0.9.        The waterproofing board according to claim 1, wherein the carbonate carbonate mineral catalyst comprises Aragonite, Calcite or Dolomite. The waterproofing board according to claim 4, wherein the dolomite is calcined dolomite calcined at a temperature of 700 to 1000 ° C. The waterproofing board of claim 1, wherein the gypsum slurry further comprises a basic catalyst other than carbonate rock minerals. A method for manufacturing a waterproof board, comprising forming an aqueous gypsum slurry containing a semi-gypsum, a silicone oil, and a carbonate rock mineral as a catalyst, and curing the slurry. The method of claim 7, further comprising the steps of: forming a water-based gypsum slurry comprising a silicone oil or an aqueous emulsion or water dispersion thereof, carbonate mineral and semi-gypsum; and molding and curing the gypsum slurry Gt;