KR20020085403A - Water-Proof Materials Comprising Bentonite as Main Component - Google Patents

Abstract

PURPOSE: A bentonite waterproof material is provided, which is reduced in the early hydration swelling and improved in the flexibility of bentonite, and is applied to the concrete joint, the base bottom and the wall in construction. CONSTITUTION: The bentonite waterproof material comprises 60-95 wt% of bentonite; 5-40 wt% of a polyurethane adhesive; optionally 0.5-3 wt% of monofilament reinforcement; and optionally 0.1-0.5 wt% of an aqueous pigment. Preferably the bentonite is sodium bentonite. The polyurethane adhesive is two liquid phase-type one consisting of a main component and a curing agent. Preferably the main component has a -NCO% of 6.2-7.2 % and a viscosity of 2,300-3,700 cps(at 25 deg.C) and the curing agent has a viscosity of 700-1,300 cps(at 25 deg.C).

Description

Bentonite Waterproofing Material {Water-Proof Materials Comprising Bentonite as Main Component}

The present invention relates to a waterproofing material of the present invention, wherein bentonite is a main component, and a waterproofing material mainly used for construction structures.

Bentonite is the third type of volcanic ash or rhyolite that has a layered structure due to the calcification of the volcanic ash, and its mineral name is montmorillonite. Edo has mines in Gyeongju province. However, bentonite, which is essential for waterproofing, is concentrated in the midwestern United States, Australia and China.

Looking at the chemical structure and properties of bentonite, bentonite is clay composed of montmorillonite-based expandable trilayer (Si-Al-Si) and is formed of Al ₂ Si ₄ (OH), a pyrophylite chemical formula. Among them, in the Gibbsite layer, which is an intermediate layer of aluminum oxide, aluminum having an electron valence of +3 is replaced with magnesium having an electron of +2, and sodium bentonite is a form in which a sufficient charge of -1 is satisfied with Na, The form satisfied with Ca is calcium bentonite.

In general, the bentonite used in the waterproofing material is sodium bentonite, because all of the superior performance including the expandability than calcium bentonite is used in almost all products using bentonite 95% or more sodium bentonite.

Bentonite swelling principle is based on the Gibbsite layer where charge disparity occurs. Each layer of bentonite has a positive polarity with positive (+) edges and negative (-) charges on the surface. In addition, the adsorbed water molecules are further adsorbed by more and more water molecules, so that the water molecules are adsorbed into the space between bentonite layers, thereby changing the bentonite structure, which is a plate-like structure, into a house of cards. It is done.

Bentonite, on the other hand, has the following typical physical properties:

(1) inflatable

When contacted with water, calcium-based bentonite expands by about three times and sodium bentonite by about 15 times and absorbs water up to five times its weight.

(2) caking

When water is absorbed after mixing different materials with bentonite, the other materials have a property of caking each other. At this time, since bentonite does not exhibit chemical activity, it does not affect the original chemical properties of the adhered material.

(3) thickening

Since bentonite forms a gel state after hydration expansion, it has the effect of concentrating other low-viscosity materials and the suspension using bentonite does not precipitate even after a long time.

(4) lubricity

Gelated bentonite has high lubrication properties and is used to lubricate various drilling operations.

Because of the physical and chemical properties described above, bentonite is used as a waterproofing means. The conventional waterproofing method according to the type of waterproofing materials is as follows: First, concrete waterproofing is a method of constructing watertight concrete by adding admixtures when placing concrete, and liquid waterproofing is inorganic to mortar of cement, sand and water mixture. Or it is a method of applying the mortar made by mixing the organic waterproofing material on the concrete sphere surface. Asphalt waterproofing is a method of forming a waterproofing layer by alternately stacking molten asphalt felt or asphalt, asphalt roofing or special asphalt roofing, and coating waterproofing is applied by applying a liquid bitumen or a polymer material to the ball several times without a seam. It is a method of forming a waterproof layer. In addition, sheet waterproofing is a method of forming a waterproofing layer by attaching a sheet of plastic or synthetic rubber to the structure with an adhesive, and bentonite waterproofing uses bentonite as a sheet, mat, panel, etc. to fix it with nails to fix the waterproofing membrane. How to form.

Advantages of bentonite waterproofing over other waterproofing include self-repairing, permanent waterproofing, easy installation and quick air, harmless to human body, ease of verification and verification, and ease of maintenance, repair and reinforcement.

On the other hand, the following patent is known as a waterproof material using bentonite. U.S. Patent No. 4,048,373 discloses a waterproof plate, which has a sheet installed on the upper and lower surfaces of an adhesive composition composed of bentonite, but has a low durability. U.S. Patent No. 4,534,926 discloses a bentonite composition comprising a mixture of bentonite and polypropene or polybutene, which has the advantage of being extruded but has the problem of requiring an extruder having a wide opening. U.S. Patent No. 4,693,923 discloses a waterproof sheet composed of sodium bentonite with an impermeable polymer film attached.

In addition, Korean Patent No. 1997-311 discloses a waterproof material mainly containing bentonite, and the waterproof material includes polybutylacrylonitrile, acrylamide and acyl acid in bentonite. However, the waterproofing material uses a harmful and odorous solvent such as toluene as a mixed solvent and has a problem of low extrudability. Korean Patent No. 225253 discloses an index material having a self-repairing function. The ash may include a waterproof material layer formed by mixing bentonite and an adhesive and a protection net additionally attached to upper and lower surfaces of the layer.

As described above, although there are many prior arts for waterproofing materials based on bentonite, bentonite waterproofing materials developed to date have a problem of overcoming elasticity, flexibility, workability, and early hydration expandability.

Many patents are cited throughout this specification. The disclosure of the cited patent is incorporated herein by reference in its entirety, so that the level of the technical field to which the present invention belongs and the contents of the present invention are more clearly explained.

As a result of earnest research efforts to solve the long-term needs of the skilled person described above, the present inventors have completed the present invention by confirming that early hydration expandability is reduced and flexibility is increased when polyurethane is added to bentonite main component to produce bentonite waterproofing material. Was done.

Accordingly, an object of the present invention is to provide a bentonite waterproofing material which is excellent in workability by reducing premature hydration expandability and increasing flexibility.

1 is a view showing an example of use of the bentonite waterproofing material of the present invention.

According to one aspect of the present invention, the present invention provides a bentonite waterproofing material comprising (a) bentonite and (b) a polyurethane adhesive.

Bentonite used in the present invention may be any bentonite used as a waterproofing material in the art, but preferably sodium bentonite having excellent hydration expandability. In order to achieve the object of the present invention, the sodium bentonite is used in an unhydrated, ie dried state. The particle size of sodium bentonite of the waterproofing material of the present invention is preferably 10-20 mesh.

On the other hand, it is produced by polyols and diisocyanates which are commonly used for polyurethane production. The polyols include polypropylene glycol, polytetramethylene glycol, polyester polyols, polyether polyols, and the like. Preferably, polyether polyols such as polyoxypropylene diol or triol of the polyol are used, more preferably polyoxypropylene glycol most preferably polyoxypropylene glycol having an average molecular weight of 1000-6000. Polyoxypropylene glycol is most preferred because of its excellent water resistance and elongation. On the other hand, the diisocyanate is aliphatic diisocyanate such as trimethyl diisocyanate; And aromatic diisocyanates such as tolyene diisocyanate, diphenyl methane diisocyanate and xylene diisocyanate. Preferably, aromatic diisocyanate is used, and most preferably diphenyl methane diisocyanate is used. The most preferable use of diphenyl methane diisocyanatle is the low viscosity, durability and chemical resistance of the product produced.

On the other hand, the polyurethane adhesive contained in the waterproofing material of the present invention can be produced in one-component or two-component form. When produced in one-part form, a prepolymer as the subject is prepared, which has an isocyanate group at the end. The prepolymer is prepared by the reaction of a polyol having a molecular weight of 1,000-6,000 with a diisocyanate. The isocyanate groups of this subject react with water in the air to form macromolecules having a network structure. In addition, when the polyurethane adhesive is produced in a two-part form, a prepolymer as a subject is produced, which has almost the same characteristics as the one-component prepolymer described above. The subject may also include plasticizers such as dibutyl phthalate, antioxidants such as tetrakis [methylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propioante] methane. In addition, the curing agent basically includes a polyol such as a polyether polyol, and further includes dibutyl phthalate as a plasticizer and dimethyltindimalate, 1,2-dimethylimidazole or bis-2-dimethylaminoethyl ether as a curing accelerator. You may. The master and the curing agent are mixed with each other immediately before use, and by mixing, end groups of both components react with each other to form a urethane bond.

According to a preferred embodiment of the present invention, the polyurethane adhesive included in the waterproofing material of the present invention is a two-component adhesive composed of a main agent and a curing agent. More preferably, the subject matter has a viscosity of 6.2-7.2% -NCO% and 2,300-3,700 (cps / 25 ° C) and the curing agent has a viscosity of 700-1,300 (cps / 25 ° C). If -NCO% of the above-mentioned subject matter is less than 6.2%, there is a problem in that workability is poor due to difficulty in mixing adhesive and bentonite due to high viscosity of the produced product, and in case of exceeding 7.2%, workability due to low viscosity of produced product There is a problem that the flexibility is worsened, such as elongation of the product.

According to a preferred embodiment of the present invention, the waterproofing material of the present invention comprises 60-95 wt% bentonite and 5-40 wt% polyurethane adhesive. If the content of bentonite is less than 60% by weight, other components are present in excess, so that the hydration expandability is greatly reduced when the waterproofing material of the present invention comes into contact with water, and when it exceeds 95% by weight, the adhesive of polyurethane There is a problem in that the content of the components, such as too small, greatly reduces the bonding force between the bentonite particles.

According to a preferred embodiment of the present invention, the bentonite waterproofing material of the present invention further comprises 0.5-3% by weight of short fiber reinforcement based on the total weight. The short fiber reinforcing agent is added to prevent the deviation of bentonite by providing excellent bendability to the waterproofing material of the present invention and maintain the basic shape even after hydration. The short fiber reinforcing agent may be any short fiber conventionally manufactured and sold in the fiber industry, and glass fiber, carbon fiber, polyester and polypropylene may be used. For example, short glass fibers can be used, which consists of components such as SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, MgO, Na ₂ O, and K ₂ O.

According to another preferred embodiment of the present invention, the bentonite waterproofing material of the present invention further comprises 0.1-0.5% by weight of a water-soluble pigment relative to the total weight. The water-soluble pigment, if the part is installed in the waterproofing material of the present invention does not play a role, that is, if there is a defect, so that the water passing through the defective part has a color, it is easy to find the defect with the naked eye. The water-soluble pigment may be any one commonly used in the art, for example, mono azo yellow and the like.

The bentonite waterproofing material of the present invention can be manufactured in various shapes. For example, the waterproofing material of the present invention can be produced in the form of a sheet (suitable for foundation floors, etc.), rectangular rolls (suitable for concrete construction joints, sleeve pipe portions, etc.).

An example of the use of the bentonite waterproofing material of the present invention made of a rectangular roll will be described with reference to FIG. 1 as follows: The accompanying FIG. 1 shows an installation aspect of a typical concrete structure, and a portion to which the waterproofing material of the present invention is applied. Is 1, 2 and 3. The waterproof material of the present invention having a rectangular shape is applied to such a joint portion and expands when it comes into contact with water, thereby exhibiting a waterproof effect.

On the other hand, since the bentonite waterproofing material of the present invention has greatly improved flexibility (elasticity), the waterproofing material of the present invention, which is manufactured in a rectangular shape, does not require the upper and lower mesh type fabrics or polyester meshes that are conventionally used. It is also possible to use the above network.

Bentonite waterproofing material of the present invention not only solved the problems of early hydration expansion, flexibility (elasticity), etc., which was pointed out as a problem of the conventional bentonite waterproofing material, the polyurethane used as an adhesive is odorless, unlike a conventional acrylic adhesive, It has an environmentally friendly property that does not contaminate water when it comes into contact with water in the surrounding environment, such as groundwater, and has the advantage of being less harmful to the human body.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, it is to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. Will be self-evident.

Example 1 Preparation of Two-Component Polyurethane Adhesive

Polyether polyol having an average molecular weight of 3000, a hydroxyl value of 35-40 mg KOH / g and an equivalent of 1500 (PPG-3000D, Kumho Chemical Co., Ltd.) 43.6 wt%, an average molecular weight of 2000, a hydroxyl value of 54-58 mg KOH / g and an equivalent weight 1000 polyether polyol (PPG-2000D, Kumho Chemical Co., Ltd.) 18.9 wt%, diphenyl methane diisocyanate (Dow Chemical Korea, Ltd.) 28.86 wt% (isonate 143 LP 18.86 wt% and isonate 125MK 10 wt%) , Dibutyl phthalate (S-FLEX (DBP), Suntec Co., Ltd.) 8.54% by weight and tetrakis [methylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (Ciga Geigy, Irganox-1010) 0.1 weight was added to the reaction mixer and stirred at 80 ° C. for 2 hours to synthesize a prepolymer. The -NCO% of the synthesized prepolymer was 6.2-7.2% and the viscosity was 2,300-3,700 (cps / 25 ° C).

On the other hand, apart from the above process, polyether polyol having a mean molecular weight of 6000, a hydroxyl value of 26-30 mg KOH / g and an equivalent of 2000 (PPG-6000D, Kumho Chemical Co., Ltd.) 51.9 wt%, an average molecular weight of 5000, and a hydroxyl value of 31- Polyether polyol (PPG-5000D, Kumho Chemical Co., Ltd.) with 35 mg KOH / g and equivalent weight of 1650 20% by weight, and polyether polyol with an average molecular weight of 4000, 40-44 mg KOH / g and equivalent weight of 1333 (PPG -4000D, Kumho Chemical Co., Ltd. 20% by weight, Dibutyl phthalate (S-FLEX (DBP), Solar Corporation) 6.8% by weight, and Stainers Octoate (DABCO T-9, Air Products) G) 0.65 wt% and bis (2-dimethylaminoethyl) ether (ZF-20, Huntsman) were added to the reaction mixer and stirred for about 1 hour to synthesize a curing agent. The viscosity of the synthesized curing agent was 700-1,300 (cps / 25 ° C.).

Example 2 Preparation of Bentonite Waterproofing Material of the Present Invention

The prepolymer and curing agent of the polyurethane adhesive prepared in Example 1 were mixed in a weight ratio of 70: 100 and sodium bentonite was added so that the weight ratio of the resulting mixture to sodium bentonite was 20:80. The reaction mixture was then stirred and reacted at 20-40 ° C. for 7 hours. The reaction product was then compacted to 100 bar and molded to a constant width and thickness of 15 mm. Then, the molded article was dried by natural ventilation and cut to a width of 23 mm using a blade to prepare a roll-shaped final product.

Example 3 Preparation of Bentonite Waterproofing Material of the Present Invention II

The same procedure as in Example 2, except that the weight ratio of polyurethane adhesive to sodium bentonite was 10:90 to prepare a waterproof material.

Example 4 Preparation of Bentonite Waterproofing Material of the Invention III

In the same manner as in Example 2, but the weight ratio of the polyurethane adhesive to sodium bentonite was 15:85 to prepare a waterproof material.

Example 5 Preparation of Bentonite Waterproofing Material of the Invention IV

The same procedure as in Example 2 was carried out except that the weight ratio of the polyurethane adhesive to sodium bentonite was 25:75 to prepare a waterproof material.

Example 6 Preparation of Bentonite Waterproofing Material of the Invention V

In the same manner as in Example 2, a waterproofing material was prepared by further mixing 2% by weight of short fiber reinforcing agent (Faiba Korea Co., Ltd.) based on the total weight of the sodium bentonite and polyurethane adhesive mixture.

Example 7 Preparation of Bentonite Waterproofing Material of the Present Invention VI

In the same manner as in Example 2, 0.3 wt% of the water-soluble pigment (Samsung Pigment Co., Ltd.), which is an azo pigment having a mono azo group, was further mixed with respect to the total weight of the sodium bentonite and the polyurethane adhesive mixture. .

Comparative Example 1 Preparation of Conventional Bentonite Waterproofing Materials

30% by weight of the acrylic oil-based adhesive and 70% by weight of bentonite were mixed in the stirrer for about 5 minutes, poured into mold plates meeting each specification, and a molding press was performed with a roller. Subsequently, the polyethylene net was attached and dried for 48-72 hours, and then cut according to the specification. The manufactured waterproofing material tended to harden due to severe hardening with time, and the product had to wear a gas mask due to bad smell caused by harmful ingredients such as toluene.

Experimental Example 1: Physical property test of bentonite waterproofing material of the present invention

The physical properties of the waterproofing materials prepared in Examples 2-6 and Comparative Examples were tested, and the results are shown in Table 1 below:

Test Items Test Methods Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example Hydrostatic pressure test (50M) ASTMD 5385 No leak No leak No leak No leak No leak No leak Tensile Load (kgf / inch ² ) KSM 6518 14 11.9 13.1 14.9 14.3 8.8 Tensile Load After Aging (kgf / inch ² ) KSM 6518 13.8 11.7 13 14.8 14.2 8.6 Elongation (%) Client provided 75 38 52 169 78 29 Volume expansion rate (20 hours) (%) Providing Client 159 410 243 110 160 229 Volume expansion rate (40 hours) (%) 179 468 308 154 175 279 Swelling degree (ml) ASTMD 5890 19 22 21 17 20 16 Dissolution test Bosa Department Notice Not dissolved Not dissolved Not dissolved Not dissolved Not dissolved Eluted Cold resistance ASTMD 1790 clear clear clear clear clear clear Flexibility (1 month) Providing Client clear clear clear clear clear fracture Flexibility (2 months) clear clear clear clear clear fracture

As can be seen in Table 1, the waterproofing material of the present invention can be seen that the flexibility (elasticity) is significantly improved by the polyurethane adhesive compared to the conventional waterproofing material, and in combination with the results of tensile load, tensile load and elongation after aging Indeed, it can be seen that it exhibits excellent flexibility (elasticity) against significant external tensile stresses. In addition, it can be seen from the results for the volume expansion rate that the waterproofing material of the present invention is greatly suppressed in the early hydration expandability, it is easy to adjust the expansion rate for each time zone. On the other hand, as can be seen from the dissolution test results of Table 1, the waterproofing material of the present invention has the advantage that the construction can be carried out with little heavy metal elution when pouring concrete, such as water reservoir, the water resistance characteristics of polyurethane adhesives and urethane bonds, etc. This prevents the loss of bentonite completely.

The present invention provides a bentonite waterproofing material. The waterproofing material of the present invention is applied to various parts of a building such as concrete joints, foundation floors and walls to exhibit excellent waterproofing effects, in particular, to solve the problem of early hydration expansion, and greatly increase the flexibility of bentonite.

Claims (7)

A bentonite waterproofing material comprising (a) bentonite and (b) a polyurethane adhesive. The bentonite waterproofing material according to claim 1, wherein the bentonite content is 60-95% by weight, and the polyurethane adhesive content is 5-40% by weight. The bentonite waterproofing material according to claim 1, wherein the bentonite waterproofing material further comprises 0.5-3% by weight of short fiber reinforcement based on the total weight. The bentonite waterproofing material according to claim 1, wherein the polyurethane adhesive is a two-component type composed of a main material and a curing agent. The method of claim 4 wherein the subject has a viscosity of 6.2-7.2-NCO% and 2,300-3,700 (cps / 25 ° C.) and the curing agent has a viscosity of 700-1,300 (cps / 25 ° C.). Bentonite waterproofing material. The bentonite waterproofing material according to claim 1 or 3, wherein the bentonite waterproofing material further comprises 0.1-0.5% by weight of a water-soluble pigment based on the total weight. The bentonite waterproofing material according to any one of claims 1 to 5, wherein the bentonite is sodium bentonite.