KR20000017726A - Hydraulic inorganic coating composition - Google Patents

Abstract

PURPOSE: A composition of hydraulic mineral paint is provided to improve environmental contamination resistance, thermal resistance, air permeability, and weatherability with film peculiarity excellence. CONSTITUTION: A composition of hydraulic mineral paint comprises: a cement50-87weight percent selected one or more than one from group of a white common Portland cement, common Portland cement, mixing cement, alumina cement as main bonding materials; 201weight percent of a pozzolan material with potential hydraulic; 1-10weight percent of powder resin for a cement use; 2-15 weight percent of a quantity increasing material; 2-15 weight percent of a quantity increasing material for maintenance; 1-10 weight percent of a control agent for controlling coagulation and the hardening time; 1-10 weight percent of a dispersing agent; 0.2-5 weight percent of an aqueous polymer; 2-20 weight percent of a white pigment; and 1-20 weight percent of a color pigment.

Description

Hydraulic inorganic coating composition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic inorganic coating composition, and more specifically, a pigment that expresses additives and colors that enable ordinary functions of portland cement as a binder constituting the paint as a cement / concrete-only paint, and to function as a paint. The present invention relates to a hydraulic inorganic coating composition in which a coating film is cured by a hydration reaction of cement by mixing the components and mixing them homogeneously with water before coating.

In general, the paint is composed of a polymer, a pigment, an additive, and a solvent. Among these, the polymer is a key component of the basic skeleton of the paint and determines the basic properties of the coating. At present, most of the paints commercialized in Korea use synthetic resins as polymers. These synthetic resins have a disadvantage in that the manufacturing process is complicated, and in particular, unreacted monomers that cause environmental pollution are necessarily generated during the manufacturing of synthetic resins. .

On the other hand, the solvent is used as a component to dissolve the polymer to control the drying speed during the painting work or to improve the workability, and to impart smoothness to the coating film. Generally, organic solvents are used, and water-based paints are used for water. However, these organic solvents are mostly volatile organic compounds, which volatilize in the air to generate ozone, which causes environmental pollution and is pointed out as the biggest cause of domestic air pollution.

Therefore, in order to solve this problem, an inorganic paint using an inorganic polymer has been developed and commercialized as a binder for forming a coating film, and recently, an organic-inorganic composite paint has been developed.

Water-soluble silicates, phosphates, silicones, and the like are mainly used as inorganic binders used in inorganic paints. These inorganic paints have excellent incombustibility and thermal stability and less deterioration in ultraviolet light than organic paints. Moreover, since it is excellent in acid resistance and alkali resistance, and the hardness of a coating film is high, it shows the very outstanding characteristic as a coating material. However, these inorganic paints usually have a disadvantage in poor workability due to a separate heat treatment process after coating when cured at a high temperature, and are not used universally because they are very expensive than general synthetic paints.

Therefore, in order to solve the above problems, a study has been conducted to apply ordinary portland cement as a binder. In US Patent No. 2,934,445, an attempt was made to apply a paint using white Portland cement and water-retaining salts, pigments, and water repellents. British Patent Application No. 1372173 discloses a coating composition which can be finished with a single coating by mixing various additives so as to function as concrete, usually Portland cement and silica sand, calcium chloride and paint. However, the coating disclosed in the patent is difficult to apply as a general coating considering that the thickness of the coating film is about 3 to 5 mm and the thickness of the general synthetic resin coating is about 300 to 500 µm. Therefore, it is very difficult in terms of theoretical coating area, workability and economy. I would say poor.

Therefore, in the present invention, in order to compensate for the disadvantages of the above-described paints and inorganic paints using synthetic resin, portland cement is usually used as a main binder, and an appropriate additive is selected. In other words, instead of the organic synthetic resin or inorganic binder used in conventional paints, ordinary portland cement that is condensed and cured through hydration reaction at room temperature is used as a binder, and a suitable additive is used as a coating material to achieve similar coating properties as the conventional water-based paints. In addition, to solve the disadvantages of existing paints, such as environmental pollution and breathability, durability, weather resistance, heat resistance, such as weak physical properties, and also to develop a paint that is effective in terms of economic efficiency.

Therefore, the object of the present invention serves to improve the durability by protecting the coating material when applied to concrete secondary products as well as painting work of cement and concrete coating, there is no degradation of the coating film by ultraviolet rays, the breathability is given It is to provide a hydraulic inorganic coating composition that can exhibit excellent coating properties that can maintain a strong adhesion with.

Composition of the present invention for achieving the above object is 50 to 87% by weight of one or more cement selected from the group consisting of white ordinary portland cement, ordinary portland cement, mixed cement, alumina cement as the main binder, latent hydraulic pozzolanic material 2 ~ 15% by weight, 1-10% by weight powder resin for cement, 2-15% by weight extender, 2-15% by weight water-retaining extender, 1-10% by weight coagulation / hardening time regulator, 1-10% by weight dispersant, water-soluble polymer 0.2 It consists of-5 weight%, 2-20 weight% of white pigments, and 1-20 weight% of colored pigments.

Looking at the present invention in more detail as follows.

When the existing synthetic resin paint is coated on the cement paste surface or concrete surface, the coating material and other heterogeneous materials are coated, so the adhesiveness is good at the initial stage of forming the coating, but the air permeability is almost absent, and the time elapses due to the difference in thermal expansion coefficient with the coating material. As a result, the adhesive performance is reduced. In addition, when water is supplied from the outside due to cracks on the interface between the coating and the coating film, or when the water inside the coating moves to the interface, the coating film swells by reacting with water-soluble salts or alkali components, which are mainly formed on the surface of the cement and concrete. And phenomenon such as separation of the coating film.

However, when the paint prepared according to the present invention is used on the surface of cement and concrete, since the formed coating film is the same material as the coating material, the adhesion between the coating material is excellent and the air permeability is given to the coating film. Coating separation does not occur.

The present invention uses a cement selected from the group consisting of white ordinary portland cement, ordinary portland cement, mixed cement and alumina cement as the main binder to produce a paint suitable for the coating of cement and concrete coatings. White portland cement is used to facilitate color expression, which is an important property of the process.

Portland cement is commonly referred to as tricalcium silicate (hereinafter referred to as "C ₃ S"), dicalcium silicate (hereinafter referred to as "C ₂ S"), tricalcium aluminate (hereinafter referred to as "C ₃ A") and tetracalcium aluminium. No ferrite (hereinafter referred to as "C ₄ AF") compounds account for more than 90% of the total constituents. White ordinary portland cement has a higher C ₃ A content than ordinary portland cement and iron oxide to increase the whiteness of the cement. It is characterized by low C ₄ AF content by using less raw materials. In addition, the mixed cement is a cement made of a mixture of a material or pozzolanic material which does not have hydraulic properties in itself, such as slag, natural and artificial silica, and fly ash, but which has latent hydraulic properties by alkali stimulation in the presence of water. Alumina cement is different in content of alumina depending on the purpose of use, but usually shows fastness and portland cement forms calcium silicate hydrate, whereas alumina cement forms alumino calcium hydrate.

Since each of the above-mentioned cement compounds have different physical properties, the properties exhibited by the hardening of cement are not necessarily represented by any compound, but in cement, C ₃ S and C ₂ S account for 60% or more of the total compound. As such, most of the properties depend on these two compounds. These cement minerals react with water to produce calcium silicate hydrate and calcium hydroxide. This reaction is called a hydration reaction, and a stable state of hydrate is produced through an initial hydration, condensation, and curing process through this hydration reaction.

Briefly described the curing mechanism of the cement-based inorganic paints according to the present invention. The hydration reaction of C ₃ S and C ₂ S, the main constituent minerals of white ordinary Portland cement, produces calcium silicate hydrate and calcium hydroxide, and the double calcium silicate hydrate becomes the binder of the coating film. In addition, the calcium hydroxide moves to the surface of the coating film and reacts with carbon dioxide gas dissolved in the air or in water to form insoluble calcium carbonate on the surface of the coating film to stabilize the surface. The coating properties of the paint are largely determined by the crystal grains of the calcium carbonate produced. Compared to the calcium carbonate, which is usually neutralized on the concrete surface, the crystal grains are very small and dense and form an insoluble coating surface layer. It acts as a protective layer to prevent this from being neutralized, thereby enhancing durability.

The cement according to the present invention is used in 50 to 87% by weight, when less than 50% by weight, the amount of the binder is relatively insufficient to reduce the bonding strength to form a coating film, if it exceeds 87% by weight to exert the function as a paint There is a tendency that the amount of the additives is reduced so that properties such as initial adhesiveness, flexibility, hiding power, and the like decrease. In addition, the cementity of the cement should be at least 3000 cm ² / g or more (Blaine value) in order to reduce the hydration reactivity and the cohesion of the particles.

As described above, the coating composition prepared by the present invention uses white ordinary portland cement as a main binder, and thus, there are many differences from conventional synthetic resins. Therefore, if only a mixture of cement and pigment and water (solvent) is used, since only the pigment is added to color the existing cement paste, it will not satisfy the characteristics as a paint. Therefore, while maximizing the advantages of the original cement component should also satisfy the function as a paint, to perform this role is the function of the additives used in the present invention.

First, the coating composition prepared by the present invention contains 2 to 15% by weight of latent hydraulic pozzolanic materials such as slag, fly ash, silica fume and / or meta kaolin, which improves the latent hydraulic properties of the raw materials and the fluidity of cement. It helps. That is, the raw material particles are filled between the cement particles having a relatively large particle size to improve the compactness, and as the hydration reaction of the cement proceeds, it is stimulated by alkali ions, so that the hydration reaction occurs in a chain to form a coating layer. It will be done. By this reaction, the coating film has a dense microstructure, which is usually difficult to obtain only by Portland cement alone. In addition, extenders such as calcium carbonate, slaked lime, and / or silica are used in an amount of 2 to 15% by weight to improve the density and whiteness of the coating film. In this case, the initial curing property is low and the choking occurrence tends to be remarkable. The powder level (brain value) of latent hydraulic pozzolanic material or extender is about 4000 ~ 8000cm ² / g, but it is advantageous that the particles can be smaller than cement, but when the particles are too small (Brain specific surface area: 8000cm ² / g or more) ), The cohesiveness between the particles increases to show the property of agglomeration, which makes it difficult to mix homogeneously when mixed with water.

In the present invention, in addition to the cement used as the main binder, a powder powder for cement, which serves as an auxiliary binder, was used to improve the adhesion and workability of the paint, flexibility of the coating film, and plasticity. The powder resins used are vinyl acetate based, vinyl ester based, vinyl chloride based, vinyl laurate based, and / or ethylene based. The cement powder resin is dissolved in water used as a solvent to form a film by filling around the hydrate particles and the pores with little effect on the hydration reaction of the cement, and the film forms the adhesion between the hydrate and the adhesion between the coating and the coating film. Serves to improve the In addition, by using such a water-soluble polymer powder, the plasticity of the polymer material itself has the property that the plasticity of the coating film is improved and the bending strength is improved, and workability is also enhanced. The water-soluble polymer powder according to the present invention is used in an amount of 1 to 10% by weight, but when the added amount is less than 1% by weight, workability and adhesion between the coating material and the coating film are decreased, and when the water content exceeds 10% by weight, the coating film strength tends to decrease. .

In addition, in order for the cement to be condensed and cured through the hydration reaction, sufficient moisture must be supplied. However, in order to maintain proper workability by mixing the coating composition with water and to have a constant viscosity, the amount of added water does not exceed a certain range. However, in consideration of this point, if the amount is added, the amount of water is less than the amount of water necessary for sufficient hydration reaction to occur, and the coating film strength is lowered. Therefore, there is a need for a conservative raw material so that the raw material mixture can contain more moisture when reacting with moisture. In addition, the specific gravity of the cement, which occupies most of the coating composition, is about 3.1 g / cm ³ , which is very high, resulting in material separation when mixed with water, thereby minimizing material separation when the final coating composition is mixed with water and becomes liquid. In order to achieve this, a very light raw material is needed. Therefore, in the present invention, 2 to 15% by weight of porous silica powder such as pearlite and vermiculite having a specific gravity of 0.1 g / cm ³ or less was used to solve water separation and cement material separation at the same time.

On the other hand, when the cement is mixed with water and stirred, several or tens of particles are present in aggregate with each other without being dispersed in individual states of the cement particles. This is because the cohesive force between the cement particles is stronger than the force remaining on the surface of the cement particles and repulsing with each other, and this tendency also exists in the case of pigments. Therefore, it is necessary to have a dispersant that keeps the raw material particles well dispersed so that material separation does not occur during the construction work, and that the aggregated particles in the coating film do not protrude and form a homogeneous coating surface after coating. In the invention, 1 to 10% by weight was used. Such dispersants are dissociated into active anions and cations in water, and the active anions are adsorbed on the interface of cement particles to form a charge layer on the surface of the particles, thereby effectively dispersing them by electrostatic repulsion. In addition, when the raw material for forming the paint is mixed with water, the effect of improving workability can be expected by providing proper fluidity. Examples thereof include polycarboxylic acid dispersants, melamine dispersants, amino sulfonic acid dispersants and / or naphthalene compounds. Dispersants and the like. More specifically, the dispersing agent is one selected from the group consisting of polycarboxylic acid compound, polycarboxylic acid ether, melanin sulfonate formalin condensate, aromatic amino sulfonic acid, naphthalene sulfonate, polyalkylaryl sulfonate, and alkyl naphthalene sulfonate More than that is chosen.

In general, the hydration of the cement takes about 8 to 10 hours until the condensation through the initial phase, and the curing reaction takes a very long time. Therefore, in order to satisfy the workability as a paint, it is necessary to adjust the setting time to satisfy the drying time range of the general paint. In the present invention, in order to solve the above problems by controlling the initial hydration reaction rate of the cement was added a condensation time regulator to satisfy the construction conditions and repaintable time according to the season during the coating work, such as the coagulation time regulator Chlorine compounds, such as soda and calcium chloride, acetate, nitrate, etc. can be used individually or in mixture, The use amount is 1-10 weight% is preferable.

In addition, the water-soluble polymer is added in an amount of 0.2 to 5% by weight, in order to improve workability by increasing the viscosity of the liquid paint state mixed with water, and to increase the initial adhesion of the paint component to the cement and concrete coating materials. As the water soluble polymer, methyl cellulose, cellulose ether, and / or polyvinyl alcohol acetate and the like can be used.

In addition, a white pigment such as titanium dioxide in the rutile crystal phase used to increase the hiding power of the paint is used at 2 to 20% by weight, and a colored pigment is used at 1 to 20% by weight. In addition, other additives such as an antifoaming agent used to remove bubbles generated when mixed with water may be used. This coating composition is used by mixing with 80-200 weight part of water with respect to 100 weight part of total raw materials.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

White Regular Portland Cement 75%, Slag Fine Powder 8%, Cement Powder Resin (trade name: Vinapas RI 551Z) 2% by weight, Pearlite 5%, Calcium Chloride 1%, Lignin Sulfonate 2%, Titanium Dioxide 5% %, 1% by weight of methyl cellulose and 1% by weight of an antifoaming agent (trade name: Agitan P803) were homogeneously dry mixed, and then water (waterworks) was added at 130 parts by weight based on 100 parts by weight of the total powder to obtain about 5 parts in a mixer. Mix once more homogeneously again. The coating composition in the slurry state thus prepared was applied twice to the concrete wall by airless spray coating. At this time, the surface of the concrete coating was performed by spraying before spraying the coating so that the moisture was not completely dried. After painting, the coating was left at room temperature until the coating was cured. At this time, the thickness and coating film characteristics of the cured coating film are shown in Table 1 below.

Example 2

White Medium Portland Cement 70%, Silica Fume 3%, Slaked Lime 2%, Cement Powder Resin (trade name: Vinapas RI 552Z) 5% by weight, Porous Silica 7% by weight, Titanium Dioxide 7%, Naphthalene Dispersant 1% by weight %, 2% by weight of calcium chloride, 2% by weight of polyvinyl alcohol and 1% by weight of an antifoaming agent (trade name: Agitan P803), followed by mixing by adding 150 parts by weight of water to 100 parts by weight of the total powder. Coating was carried out in the same manner as 1, and the properties of the cured coating film are shown in Table 1 below.

Comparative Example 1

The white synthetic resin emulsion water-based paint, which is generally used for painting concrete walls in Korea, is coated twice using airless spray on the dried concrete surface and the characteristics of the cured coating film after drying at room temperature are shown in Table 1 below.

TABLE 1

Coating Properties Prepared by Coating Compositions and Emulsion Water-based Coatings Prepared by the Present Invention

As described above, the present invention is an inorganic raw material using white ordinary portland cement, which is an inorganic raw material as a binder, and most other additives are applied to cement, and an environmental pollution which is a disadvantage of the conventional synthetic resin paint as a coating composition using water as a solvent. And fundamentally solved the problems of long-term durability, such as water resistance, weather resistance. And the manufacturing process of the paint is very simple, consisting of only a simple grinding and mixing process, and the raw material is also very economical because it is a low-cost raw material can be easily obtained in Korea. In addition, there is an advantage that the work process can be simplified because it can be applied directly on the cement and concrete coatings without a separate surface treatment work or putty work before painting. In particular, the paint composition exhibits excellent properties such as durability, water resistance, weather resistance, etc. when applied to civil engineering structures such as apartment walls, bridge piers, overpasses, and is also effective as a finishing material for repairing old concrete surfaces that are not surface treated. In addition, when applied to concrete secondary products such as cement blocks, bricks, roof tiles, road boundary stones, etc., it shows very excellent coating properties in terms of UV resistance, freeze-melt resistance, and durability.

Claims (8)

50 to 87% by weight of one or more cement selected from the group consisting of white ordinary portland cement, ordinary portland cement, mixed cement, alumina cement as main binders, 2 to 15% by weight latent hydraulic pozzolanic material, 1 to 10 powder powder for cement % By weight, 2 to 15% by weight extender, 2 to 15% by weight water retaining agent, 1 to 10% by weight condensation and curing time regulator, 1 to 10% by weight dispersant, 0.2 to 5% by weight water-soluble polymer, 2 to 20% by weight white pigment Hydraulic inorganic paint composition, characterized in that consisting of 1% to 20% by weight and colored pigments. The hydraulic inorganic coating composition according to claim 1, wherein the latent hydraulic pozzolan material is selected from the group consisting of slag, silica fume, fly ash and metakaolin. The hydraulic inorganic coating composition according to claim 1, wherein the extender is selected from the group consisting of calcium carbonate, slaked lime and silica. The hydraulic inorganic coating composition of claim 1, wherein the cement resin is selected from the group consisting of vinyl acetate, vinyl ester, vinyl chloride, vinyl laurate and ethylene. The hydraulic inorganic coating composition according to claim 1, wherein the water-retaining extender is a lightweight porous material having a specific gravity of 0.1 g / cm ³ or less. The hydraulic inorganic coating composition according to claim 1, wherein the setting and curing time adjusting agent is selected from the group consisting of sodium carbonate, calcium chloride, acetate and nitrate. The method of claim 1 wherein the dispersant is one from the group consisting of polycarboxylic compounds, polycarboxylic ethers, melanin sulfonate formalin condensates, aromatic amino sulfonic acids, naphthalene sulfonates, polyalkylaryl sulfonates, and alkyl naphthalene sulfonates Or more than one selected. The hydraulic inorganic coating composition of claim 1, wherein said water soluble polymer is selected from the group consisting of methyl cellulose, cellulose ether, and poly vinyl alcohol acetate.