KR20040099010A - Making process of water paint for architecture - Google Patents

Abstract

PURPOSE: A process is provided to produce an aqueous paint for building, which can maximize covering property and dried coating thickness at one coating by maximizing a solid volume ratio(SVR) of the paint and the difference of refraction index caused by air. CONSTITUTION: The aqueous paint contains 5-20wt% of spherical hollow light silica and 5-20wt% of a spherical bubble resin. The spherical hollow light silica has an average particle size of 30-40 micrometer and a core-shell structure comprising a silica shell and the inside filled with air. And the spherical bubble resin is a styrene acrylic emulsion having an average particle size of 0.4-0.5 micrometer and a core-shell structure.

Description

Manufacturing method of water-based paints for construction {MAKING PROCESS OF WATER PAINT FOR ARCHITECTURE}

The present invention relates to a composition of an aqueous coating material for building to improve solid content and hiding power, and more particularly, to introduce a spherical hollow body lightweight silica and a spherical bubble resin capable of maximizing the difference in refractive index and solid content. When styrene acrylic emulsion is introduced (a substance left behind by volatile solvent), it minimizes the specific gravity of the paint to maximize the volume solids of the paint and maximizes the concealment by the difference in refractive index caused by air. The present invention relates to a paint composition which enables thick film coating at one time and maximizes hiding power.

In recent years, new and new paintings have been newly constructed and renovated due to the diversification of consumer's needs in new housing or high-rise apartments. In the case of coating with water-based paints, the external coating for water-based coatings on the market lacks concealing power and film thickness, so that only two coatings can be performed, resulting in a significant cost for painting and painting labor.

As a method of maximizing the concealment of conventional paints, a pigment having a relatively high refractive index was used. For example, titanium dioxide with a high refractive index (refractive index 2.73, specific gravity 4.26) is used, and calcium carbonate (refractive index 1.63, average specific gravity 2.93), magnesium silicate (refractive index 1.65, average specific gravity 2.75), aluminum silicate is used to increase the volume and filling density. (Refractive index 1.58, average specific gravity 2.75) and the like.

However, when titanium dioxide is used, the hiding power is increased, but the price is high and at the same time, the specific gravity of the paint is increased, so that the volume solid content of the paint is not reduced or affected.

As a result, until now, water-based paints for general construction have a problem that can only be used twice.

The present invention uses a spherical hollow lightweight silica and a spherical bubble resin in order to maximize the hiding power using the difference in refractive index in order to solve the problems as described above to increase the concealment by the refraction of light as thick as possible at the same time In order to design a thick film type paint, the specific gravity of the paint is minimized to maximize the volume solids (SVR), thereby finishing the existing water-based paint for painting twice with a single coating.

That is, the purpose of the present invention is to provide a composition of water-based paint for construction, which can conceal one time and obtain a thick dry coating, thereby minimizing the labor cost of painting during construction coating and significantly reducing the coating cost by using less paint. have.

Hereinafter, the preferred embodiment of the present invention will be described in detail.

As a main body of the present invention, spherical hollow lightweight silica having an average particle diameter of 30 to 40 µm in which particles were formed as independent spheres was used. This specific silica has an effective specific gravity of about 0.28, which is higher than titanium dioxide (specific gravity 4.26), calcium carbonate (average specific gravity 2.93), magnesium silicate (average specific gravity 2.75), and aluminum silicate (average specific gravity 2.75), which are commonly used as pigments in paints. Significantly lower, it can lower the paint thickening and increase the hiding power due to the difference in refractive index of light.

Fig. (1) Comparison of refractive index between styrene acrylic resin and silica

As shown in Fig. (1), the spherical hollow lightweight silica is composed of a core-shell structure composed of a shell made of silica and an internal structure filled with air. The hiding power is increased by the scattering of light.

Styrene Acrylic emulsion, a spherical bubble resin, is an opaque polymer and has a core-shell structure with fine particles having an average particle diameter of 0.4 to 0.5 μm.

In the emulsion, the interior space is filled with water, but when the coating film is dried, the water in the interior space evaporates and is replaced by air to contain air inside the particles.

This can increase the hiding power and volume solids on the same principle as spherical hollow weight silica. See picture (1)

Table (1) Refractive index of material used for general water paint

Substance Refractive index Substance Refractive index Titanium dioxide 2.73 Styrene Acrylic 1.49 Calcium carbonate 1.63 Vinyl Acetate 1.48 Magnesium silicate 1.65 air 1.003 Aluminum silicate 1.58 water 1.333 Silica 1.46

As shown in Table 1, general materials have inherent refractive indices, but when spherical hollow-weight silica or spherical bubble resins having a core-shell structure are used as described above, The warming force can be greatly improved by the scattering of light due to different refractive indices. Especially, when the air has a small refractive index, the difference of the refractive indices becomes larger and the effect is even greater.

Fig. (2) Cross-sectional comparison of light scattering between a high refractive film and a low refractive film

Figure (2) shows the path of light movement in a high-refractive index film and a low-refractive index film using spherical bubble resin and spherical hollow weight silica. The refractive index of each constituent material increases the scattering of light, which is more refracted than in a low refractive index coating.

Therefore, light that penetrates the coating film containing a material having a high refractive index does not penetrate that much. Therefore, high refractive index coatings appear opaque and white in the absence of light-absorbing particles, and virtually all incident light is refracted and scattered in the coating and reflected off the surface.

In this principle, the concealment force covering the coating part can be maximized by using the difference in refractive index.

An embodiment of the development process of the present invention is as follows.

According to the addition amount of the spherical hollow body lightweight silica and the spherical bubble resin which maximize the difference of refractive index, it manufactured by Example (1)-Example (3), respectively.

ingredient Example 1 Example 2 Example 3 Medium weight agent (1) 0.2 Dispersant (2) 0.7 Emulsifier (3) 0.4 Cryoprotectants (4) 0.8 Antifoam (5) 0.6 Preservative (6) 0.2 Acrylic Emulsion Resin (60%) (7) 22.0 Film Forming Agents (8) 1.0 Concrete Bubble Resin (9) 20.0 17.0 15.0 Spherical Hollow Silica (10) 10.0 13.0 15.0 Titanium Dioxide (11) 20.0 Aluminum Silicide (12) 19.0 water 6.1 Sum 100.0 100.0 100.0

(1) Hydroxy Ethyl Cellulose (Elementis)

(2) polyacrylates [polyacrylate-based (Rom & Haas)]

(3) Anion system [Anion system (East South Hwaseong)]

(4) Ethylene Glycol

(5) modified silicone oil (San Nopco)

(6) Organic Nitrogen System (Sungsung Precision)

(7) styrene acrylic emulsion (60% solids)

(8) ester alcohol (yeast only)

(9) Acryl Bubbl resin, solid content 38% (Rom & Haas)

(10) spherical hollow body lightweight silica (3M)

(11) rutile type (millennium)

(12) Aluminum silicate (Huber)

If the coating method of the embodiment is described in detail, the middle agent is mixed and stirred in 5% by weight of water, and then a dispersant, an emulsifier, and a cryoprotectant are added and mixed in order. Then, titanium dioxide, aluminum silicate, spherical bubble resin, and spherical hollow lightweight silica were added and stirred at a high speed of 50 µm or more at 2000 rpm.

After the high speed stirring, the emulsion mixture, the antifoaming agent, the preservative, and the film forming agent are mixed with the low speed stirring below 1000rpm, and the viscosity is adjusted by water. If necessary, a colorant may be added to prepare a paint of a desired color. The prepared paint is filtered and packaged and kept sealed at room temperature.

Table 2 below compares the concealment rate and the physical properties of the volume solids (SVR) of the paint prepared according to the addition amount of the spherical hollow lightweight silica and the spherical bubble resin.

Table (2) Comparative test results of Examples

Test Items Example 1 Example 2 Example 3 Test Methods Viscosity (Ku / 25 ℃) Specific gravity (25 ℃) Solid content (%) Closing rate (wet paint film 50㎛) Volume solid content (SVR,%) 901.45700.99556.5 901.4271.80.99859.9 901.4073.10.99962.3 KSM 5000-2122KSM 5000-2131KSM 5000-2113KSM 5000-3111KSM 5000

As shown in Table 2, the specific gravity is lowered and the hiding rate is increased as the amount of spherical hollow lightweight silica is increased.

However, since the spherical hollow lightweight silica had a specific gravity of 0.28, it was impossible to add more than 15% due to the critical volume (CPVC) in the paint.

In addition, as the amount of spherical bubble resin increased, the concealment rate increased, but the solid content was 38% and the specific gravity was 1.03. Therefore, the volume solid content (SVR) did not increase at more than 15%.

In order to compare the physical properties of the paint of Example 3) prepared in the present invention with commercially available external water-based paints, comparative experiments were performed.

Comparative Example 1) is a building aqueous outer KS1 grade and Comparative Example 2) a building aqueous outer KS2 grade. Table 3 shows the results of testing according to the KS standard.

Table (3) Comparative test results with general water-based paints

Yield Example 3 Comparative Example 1 Comparative Example 2) Test Methods Viscosity (Ku / 25 ℃) 90 90 90 KSM 5000-2122 Specific gravity (25 ℃) 1.40 1.36 1.40 KSM 5000-2131 Nonvolatile matter (%) 73.1 57.2 53.3 KSM 5000-2113 Pigment content (%) 54.0 37.0 41.0 KSM 5000-2111 Volume solids (%) 62.3 41.5 34.2 KSM 5000 Concealment rate (wet coating film 50㎛) 0.999 0.923 0.915 KSM 5000-3111 Thermal stability line (60 ℃) clear clear clear KSM 5310 Freeze Stability (-5 ℃) clear clear clear KSM 5310 Accelerated weather resistance (ΔE) 0.06 0.06 0.07 KSM 5000-3031 State in container clear clear clear KSM 5000-2011 Workability Excellent Good Good KSM 5000-2421 Dry coating state clear clear clear KSM 5000-2421 Alkali resistance clear clear clear KSM 5000-3411 Wash resistance 1500 times or more 1500 times or more 1200 times or more KSM 5000-3351

As shown in Table (3), Example 3) was 16 to 20% higher in nonvolatile content than Comparative Examples 1) and 2), and its specific gravity was similar to Comparative Examples 1) and 2), but the hiding rate was much higher.

In addition, it can be seen that the volume solid content of Example 3) is significantly different, so that the dry coating thickness is 1.5 times thicker than Comparative Example 1) and 1.8 times thicker than Comparative Example 2).

The present invention maximizes the concealment of the invisible part of the coating by using the difference in refractive index and increases the volume solids that combine the coating thickness after the volatile solvent is blown to form a thick dry coating film at one time. It is possible to paint the troublesome time of painting twice, so that the labor cost and paint requirement can be greatly reduced.

Claims (2)

A composition of excellent aqueous coating material for construction, characterized by containing 5-20% by weight of spherical hollow weight silica and 5-20% by weight of spherical bubble resin. A composition of a water-based construction paint having a thick film of 50 to 60% by volume (SVR) using a styrene acrylic resin of 60% solids, including claim 1.