KR100972316B1 - Polymer cement waterproofing agent by using water soluble styrene and acrylpolymer - Google Patents

Abstract

PURPOSE: A water resistant dispersing agent of a polymer cement waterproof agent is provided to improve dispersibility, to prevent propertied of a coated film from being degraded due to moisture, and to give water repellency to the coated film. CONSTITUTION: A water resistant dispersing agent of a polymer cement waterproof agent is a water-soluble copolymer composition which is obtained through suspension polymerization of 120~170 parts by weight of (meta)acrylic acid, 50~70 parts by weight of (meta)acrylate, and water based on 100.0 parts by weight of styrene. The water-soluble copolymer composition is controlled to have pH value of 8~12 using ammonium hydroxide.

Description

Inorganic elastic coating waterproofing material using water-soluble styrene and acrylic resin composition {POLYMER CEMENT WATERPROOFING AGENT BY USING WATER SOLUBLE STYRENE AND ACRYLPOLYMER}

Concrete structures, reservoirs, and civil engineering structures, which are exposed to moisture for a long time due to the characteristics of concrete, are deteriorated due to the neutralization of concrete due to the infiltration of moisture. There are many problems such as loss of energy, reduction of cooling and heating effect due to increase of building water content.

Therefore, various types of waterproofing materials or water repellents are applied to prevent exposure to moisture, and such waterproofing materials can be mixed on the concrete surface by mixing two or more materials such as urethane waterproofing materials, epoxy waterproofing materials, and inorganic elastic coating waterproofing materials in the field. Coating-type waterproofing material that prevents the penetration of moisture by forming a waterproof coating on the concrete surface, and silicone or silicate diluent is applied to the concrete surface to adsorb and react on the concrete to impart water repellency to the concrete surface, thereby preventing the penetration of moisture. Type water repellents are used.

Among the above-mentioned waterproofing materials, as mentioned in Korean Patent Publication Nos. 2003-0027525 and 2002-0059060, there is a urethane coating waterproofing material which is used by mixing and diluting a polyurethane or a urethane prepolymer in a solvent, but a urethane coating waterproofing material is a product diluted in a solvent. In addition to the VOC regulation and environmental pollution by using the, there is a problem such as the risk of workers exposed to volatile solvents for a long time, and also the problem due to poor adhesion of the water-absorbing concrete rooftop floor has been discussed.

In the Republic of Korea Patent Publication No. 2002-0065566, etc., the development of a coating film waterproofing material using a water-dispersible urethane resin is proposed, but has not been widely used because it does not solve the problems such as ultraviolet resistance of the urethane itself.

In order to solve the problems of the urethane coating waterproofing material as described above, a powder composed of liquid product (A) and cement, silica sand, etc. of ethylene vinyl acetate copolymer resin emulsion or (styrene) acrylate copolymer resin emulsion in the Republic of Korea Patent Publication No. 2005-0000816 It is proposed an inorganic elastic coating film waterproofing material composed of a mold product (B), in which products A and B are mixed at a ratio of 0.5: 1.0 to 1.0: 0.5 and applied to a concrete structure.

As the inorganic elastic coating waterproofing material does not use solvents, it not only improves environmental regulations and workability due to solvents, but also has high moisture adhesion and good adhesion to urethane or asphalt waterproofing materials on the surface of buildings containing moisture. Increasing use is being made inside or underground construction and civil engineering structures. In addition, compared with the urethane coating waterproofing material, there is a characteristic that the physical properties of the coating due to rain before and after construction in summer are less.

As mentioned above, the inorganic elastic coating waterproofing material is used in a wide range because it is less affected by factors such as the moisture content of the concrete, the climatic conditions of the construction, the proficiency of the contractor, etc., but the cement is used as one of the waterproofing materials. There is a problem to follow the curing and curing conditions of cement.

Therefore, when the inorganic elastic coating waterproofing material is exposed to a lot of moisture, such as rainy weather, condensation, etc. during the curing period of about 1 week to 2 weeks, the emulsion contained in the waterproofing material absorbs moisture, thereby preventing cement hardening or The hydrolysis of the polymer resin component is accelerated to cause problems such as a decrease in strength, cracking, and lifting of the waterproof coating film.

Korean Patent Laid-Open Publication No. 2006-0102384 and Korean Patent Laid-Open Publication No. 2001-0057550 et al. Propose to use a silicone emulsion mixed with an inorganic elastic coating waterproofing material. The silicone emulsion coated on the concrete surface by mixing with the inorganic elastic coating waterproofing material penetrates into the concrete substrate to exert water repellency and at the same time gives hydrophobicity of the waterproof coating to reduce the influence of water, but the water repellency by the silicone component There is a problem in that the waterproof coating film has a decrease in the strength of itself, and the crack resistance that cracks do not occur in response to concrete cracks is inferior.

In the present invention, not only improves the dispersibility of powder components such as cement and silica sand of the inorganic elastic film waterproofing material by mixing with the inorganic elastic film waterproofing material, but also by the emulsifier added in the process of emulsion polymerization of a polymer containing acrylic or EVA as a main component. In order to suppress hygroscopicity, a water-soluble copolymer composed of 120 to 170 parts by weight of (meth) acrylic acid and 50 to 70 parts by weight of (meth) acrylate is synthesized based on 100 parts by weight of styrene.

The water-soluble copolymer synthesized as described above is characterized by improving the water resistance of the inorganic elastic coating waterproofing material and the particle dispersibility of cement and the like when used by mixing the inorganic elastic coating waterproofing material so as to be 2 to 5%. If the use of the water-soluble copolymer is less than 2%, the dispersibility is not large, but the water resistance decreases, and when the cured film of the inorganic elastic coating waterproofing material is exposed to moisture such as rain or condensation, the water absorbs moisture and the coating film strength decreases. Will be.

The water-resistant dispersing agent of the present invention improves the dispersibility of the cement of the inorganic elastic coating waterproofing material to impart the overall cement homogeneity of the completed coating film, so that stable quality can be expected, and condensation from the outside atmosphere during curing of the inorganic elastic coating waterproofing material It is possible to prevent the deterioration of the physical properties of the coating film due to water absorption due to rainfall, and also to impart water repellency to the coating film to prevent condensation from occurring where condensation easily occurs, such as underground structures.

Cement dispersion of inorganic elastic coating waterproofing material includes physical dispersion caused by agitator's stirrer and installation by roller or brush in the field, and chemical dispersion by emulsifier mixed in synthesizing acrylic or EVA emulsion. Since it does not give sufficient dispersion effect, it is impossible to expect a constant cement dispersibility in a large construction area. In order to solve this problem, an emulsifier is additionally added, but the addition of such an emulsifier accelerates the property of adsorbing external moisture on the surface of the coating after the inorganic elastic coating waterproofing is cured, thereby lowering the wet strength of the inorganic elastic coating waterproofing. do.

However, when the water-resistant dispersant of the present invention is mixed with an inorganic elastic coating waterproofing material, there is a characteristic of improving the dispersibility of cement particles so as to exhibit a certain coating property for a large construction area.

As mentioned above, the inorganic elastic coating waterproofing material has wettability of absorbing moisture of the inorganic elastic coating waterproofing layer whose cement hardening is terminated by an emulsifier mixed in the emulsion component or an additionally incorporated emulsifier. In the inorganic elastic coating waterproof layer exposed to moisture such as rain or condensation from the outside, the strength of the inorganic elastic coating waterproof layer is reduced due to the decrease in cement properties similar to the cement whitening phenomenon.

The water-resistant dispersant of the present invention is characterized by providing hydrophobicity to the inside of the inorganic elastic coating film waterproofing layer to suppress a decrease in the wet strength of the waterproofing layer due to the sizing effect.

Inorganic elastic coating waterproofing material has a good adhesiveness to the base surface of the damp concrete structure is widely used as waterproofing of the inner wall of the building, but the surface of the hydrophilic adult inorganic elastic coating waterproofing layer easily absorbs moisture in the air. Therefore, in the condition that condensation is likely to occur like the basement of a building, water damage similar to that of the interior is caused by condensation on the surface of the waterproof layer. However, the inorganic elastic coating waterproofing material mixed with the water-resistant dispersing agent of the present invention can be expected to provide an effect of preventing the formation of condensation by giving hydrophobicity to the surface of the waterproofing coating layer.

If the waterproofing layer is exposed to continuous moisture for a long time, such as non-exposed waterproofing on the roof of a building or the underground inner wall of the building or civil engineering structure, strong alkaline water is generated by adsorption with concrete. Alkaline moisture appears to react with the acrylic emulsion in the coating waterproofing layer to generate an acidic substance. These acidic substances promote hardened cement decomposition, causing cracking or decomposition of the inorganic elastic coating waterproof layer. It may also cause problems by causing neutralization of the concrete structure under the waterproofing layer.

However, the water-resistant dispersant of the present invention is adsorbed on the surface of the emulsion component to prevent alkaline moisture from contacting the emulsion particles to prevent the decomposition of the emulsion, the waterproof layer can exhibit a continuous waterproof performance, limit the generation of acidic substances to neutralize the cement The inhibitory effect can be expected.

Since the water-resistant dispersant of the present invention adsorbs on the surface of cement crystals or emulsion particles constituting the waterproofing layer, it was confirmed that there is no change in the physical properties of the waterproofing layer itself. Rather, due to the water-resistant dispersant of the present invention adsorbed on the surface of the pores inside the waterproofing layer, it was shown to impede the adsorption of moisture to slightly improve breathability. Reducing the moisture content in the waterproofing layer also appears to help improve the tensile performance of the coating layer itself.

The water-resistant dispersing agent of the present invention is characterized in that it is used as a styrene, acryl-based terpolymer copolymer resin mixed in an inorganic elastic coating waterproofing material having a cement, silica sand, acrylic or EVA emulsion in 2 to 5% by weight.

The water-resistant dispersant according to the present invention may be selected according to the mixing ratio of the styrene monomer, the acrylate monomer, and the acrylic acid monomer, the reaction temperature, the reaction time, the type and injection time of the catalyst, the type and mixing ratio of water and alcohol used as the polymerization solvent. Careful attention is required because the difference in the degree of water repellency or water resistance of the final copolymer obtained is large.

The amount of styrene monomer used for copolymerization should be 30 to 40% by weight based on the total monomer content. The higher the content of the styrene monomer, the better the water repellency of the obtained polymer. However, the water solubility in water decreases, so that the water-soluble copolymer cannot be obtained. On the contrary, when used at 30% by weight or less, the water-soluble copolymer can be obtained. The water repellency of is not expressed.

Ethyl acrylate and butyl methacrylate may be used as the methacrylate monomer, and the amount of the acrylate may be used in an amount of 15 to 25 wt% based on the total monomer content. Like the styrene monomer, when the amount of the methacrylate monomer is more than 25% by weight, the water repellency of the polymer is improved and the adhesion with the particles in the waterproofing layer of the coating is also improved, but the water solubility in water is decreased, so that a transparent water-soluble copolymer cannot be obtained. When the weight% or less is used, it is difficult to obtain a homogeneous coating waterproofing layer by reducing the dispersibility of the Simet particles.

Acrylic acid and methacrylic acid may be used as the (meth) acrylic acid monomer, and the amount of the monomer may be 35 to 45% by weight based on the total monomer content. When the amount of the (meth) acrylic acid monomer used exceeds 45% by weight, the water solubility of the obtained polymer is improved, and the dispersibility of the cement component may be somewhat improved by mixing with the inorganic elastic coating waterproofing material, but water resistance and water repellency have been shown to decrease rapidly.

The monomers are mixed with a mixed solution of water and alcohol, respectively, to proceed with the polymerization reaction, and the alcohol used has good solubility with the monomers to perform well as a reaction solvent, and can be recovered after completion of the reaction. One or more alcohols among tertiary alcohols, methanol, ethanol, n-propanol, isopropanol and butanol can be selected and mixed with water or used alone. The amount of the reaction solvent mixed with water and alcohol may change little by little depending on the content and the mixing ratio of the monomers used, preferably 100 to 300% of the total monomers.

Ammonium persulfate, potassium persulfate, hydrogen peroxide, perbenzoic acid, and the like may be used as the catalyst used in the reaction, and the amount of use is preferably 5% or less, preferably 2-4%, based on the total monomer content.

The reaction may be used by mixing the monomer and the reaction solvent in a reactor provided with a reflux unit, and may be polymerized by dropwise injection of a portion or all of the monomer during the reaction, if necessary. The catalyst is also sufficiently dispersed and dissolved in the same vessel using the same reaction solvent, and then dropwise added at a constant rate throughout the polymerization to proceed with the polymerization reaction. The reaction temperature is preferably about 70 to 80 degrees, and the polymerization may be carried out simultaneously with reflux at the distillation temperature of the alcohol used as the reaction solvent.

After the polymerization reaction is completed, the polymer solution is cooled to room temperature and neutralized with ammonium hydroxide. The neutralized aqueous copolymer resin solution may not recover the alcohol component in the solution, if necessary, but the remaining alcohol may be used in the inorganic elastic coating waterproofing material to reduce the water resistance. The alcohol is recovered using a distillation apparatus or the like, the ammonium hydroxide is adjusted to pH 8-12, and water is added to adjust the concentration of the solid content to 10-30%.

The aqueous polymer solution obtained by the above method may be used as the water-resistant dispersant of the present invention, and may be used by adding 5 to 10% to the polymer resin product in the polymer mixed cement waterproofing material on the market, or as a separate product for the entire inorganic elastic coating waterproofing material in the field. When mixed and used in a 2 to 5% weight ratio, the water resistance and water repellency can be improved without changing the waterproof performance of the inorganic elastic coating film waterproofing material.

The water-resistant dispersant obtained in the following example was added to the general inorganic elastic coating waterproofing material to compare the change in strength under wet conditions, and the evaluation method of KS F 4919 cement-incorporated polymer waterproofing material was compared for the specimens after 14 days of curing. It was.

Synthesis of Water Resistant Dispersant

Example 1

A 500 mL four-necked flask was equipped with a stirrer, a reflux condenser, a thermometer, and 40 g of distilled water and 160 g of isopropyl alcohol were slowly stirred. 30 g of styrene monomer, 20 g of ethyl methacrylate, and 50 g of acrylic acid are slowly added thereto, followed by stirring to ensure complete mixing. When the solution inside the reactor becomes transparent, the temperature is raised while maintaining the stirring and heated to 80 degrees, which is the distillation temperature of isopropyl alcohol. After dissolving 3 g of ammonium persulfate, a catalyst, in 20 g of water in a separate vessel, make sure that the urea inside the reactor is maintained at 80 degrees and slowly inject the catalyst over 3 hours. After the injection of the catalyst, the solution in the reactor was kept at 80 ° C for 2 hours while continuing to stir.

After the reaction was completed, the temperature of the solution inside the reactor was cooled to room temperature, and 30 g of 25% aqueous ammonia solution was slowly injected, and the temperature was raised to 80 degrees or more to recover the alcohol. After the recovery of alcohol, the solution inside the reactor was cooled to room temperature again, and 30 g of 25% ammonia aqueous solution was injected. Then, water was added to adjust the solid content to 20% and the pH was 8-10 with the same 25% aqueous ammonia solution. Adjust

Example 2

200 g of the same water and isopropyl alcohol mixed solvent as in Example 1 were prepared, 100 g of the mixture was injected into the reaction vessel, and the remaining 100 g was mixed with the same monomer mixture as in Example 1 and prepared in a separate container. After raising the temperature inside the reactor to 80 degrees or more, the catalyst of Example 1 and the prepared monomer solution are injected over 3 hours. This process then uses the same method to prepare a polymer aqueous solution.

Example 3

A monomer mixture solution containing 50 g of styrene monomer, 20 g of ethyl methacrylate, and 80 g of methacrylic acid was prepared to prepare a polymer polymer aqueous solution in the same manner as in Example 1.

Production of inorganic coating waterproofing material

Liquid product A was mixed with 99 parts by weight of a vinyl acetate resin copolymer with 1 part by weight of antifoam. Powdered product B was prepared by mixing 25 parts by weight of alumina cement and 75 parts by weight of silica sand. The mixture was used at a ratio of. The inorganic coating waterproofing material thus prepared was added with 3% and 5% of the water-resistant dispersant obtained in the above examples, respectively, to evaluate the strength change and physical properties according to curing conditions. Curing conditions were cured under standard curing conditions of temperature 20 ± 2 ℃ and humidity 65 ± 10%. Wet curing conditions allowed water to be sprayed on the surface of curing film every 3 hours for 10 minutes at the same temperature. Was prepared. The tensile strength measured according to the curing period under these conditions is as follows.

No.
Water Resistance Powder
Addition amount
Curing condition Curing date
Tensile Strength (N / ㎡) 1 day 2 days 3 days 7 days 14 days One Example 1 3% Standard Curing Conditions 0.52 0.77 0.89 0.99 1.20 2 Example 1 3% Wet Curing Conditions 0.48 0.69 0.86 0.92 0.99 3 Example 1 5% Wet Curing Conditions 0.50 0.73 0.89 1.02 1.06 4 Example 2 3% Standard Curing Conditions 0.60 0.77 0.98 1.01 1.21 5 Example 2 3% Wet Curing Conditions 0.59 0.72 0.92 0.99 1.10 6 Example 2 5% Wet Curing Conditions 0.59 0.76 0.95 1.02 1.19 7 Example 3 3% Standard Curing Conditions 0.48 0.71 0.82 0.92 1.06 8 Example 3 3% Wet Curing Conditions 0.42 0.58 0.62 0.68 0.74 9 Example 3 5% Wet Curing Conditions 0.40 0.52 0.59 0.63 0.68 10 - - Standard Curing Conditions 0.54 0.75 0.93 1.07 1.12 11 - - Wet Curing Conditions 0.32 0.43 0.48 0.50 0.61

In order to solve the problem of lowering the tensile strength due to moisture when exposed to wet conditions such as rainy weather or condensation during the curing period, or even after long periods of curing, the wet curing conditions are added as a result of adding the water-resistant dispersant of the present invention. It was confirmed that the tensile strength at was not similar to or significantly different from the tensile strength at standard curing conditions.

Claims (2)

A solvent mixed with 40 parts by weight of distilled water and 160 parts by weight of isopropyl alcohol was copolymerized at 80 to 30 parts by weight of styrene monomer, 50 parts by weight of acrylic acid monomer, and 20 parts by weight of ethyl methacrylate monomer to pH 8-12 by ammonium hydroxide. A water resistant dispersant for use in inorganic elastic coating waterproofing materials obtained by neutralizing as much as possible. A solvent in which 40 parts by weight of distilled water and 160 parts by weight of isopropyl alcohol was mixed was copolymerized at 80 to 50 parts by weight of styrene monomer, 80 parts by weight of methacrylic acid monomer, and 20 parts by weight of ethyl methacrylate monomer to pH 8-12 with ammonium hydroxide. A water resistant dispersant for use in an inorganic elastic coating waterproofing material obtained by neutralizing so as to be obtained.