KR101183892B1 - One-component type, room-temperature curing and water-soluble top coating composition - Google Patents

Abstract

The present invention relates to a water-soluble top coat composition of high weather resistance and pollution, and more particularly to a one-component room temperature dry type water-soluble top coat composition using an organic-inorganic composite binder excellent in weather resistance and stain resistance.

Description

ONE-COMPONENT TYPE, ROOM-TEMPERATURE CURING AND WATER-SOLUBLE TOP COATING COMPOSITION}

The present invention relates to a water-soluble top coat composition of high weather resistance and pollution, and more particularly to a one-component room temperature dry type water-soluble top coat composition using an organic-inorganic composite binder excellent in weather resistance and stain resistance.

In general, the painting has an aesthetic function in addition to the fundamental function to protect the body, and many studies have been made to maintain the appearance in a beautiful state at the beginning of painting in this respect. As a result of this research, many kinds of oil-based topcoats have been developed and used successfully.

Recently, with increasing interest in the environment and energy around the world, there is a growing movement to restrict the use of organic solvents (or volatile organic compounds) derived from fossil raw materials. Intensive regulatory measures have been prepared in many countries, including Korea. Or is being implemented.

According to these demands, two-component or one-component high-temperature drying paints have been developed that have weather resistance and fouling resistance that exceed the existing oil-based acrylic paints and have a very flexible and strong coating film, but there are limitations in workability and line conditions. . Therefore, the development of a new environmentally friendly, one-component room temperature drying type high weather resistance low pollution top coat manufacturing technology is required.

Therefore, the present invention is to provide a new water-soluble top coating which can be dried at room temperature in a one-component type with environmentally friendly and excellent weatherability and fouling resistance, and flexible and tough coating film than the conventional oil-based acrylic paint.

In order to achieve the above object, the present invention is an organic-inorganic complex copolymer emulsion 40 to 60% by weight, sieving pigment 5 to 20% by weight, colored pigment 1 to 20% by weight, 3 to 10% by weight of film preparation and 5 to 40% by weight of water It provides a one-component room temperature dry type water-soluble top coat composition comprising%.

Hereinafter, the present invention will be described in detail.

In the present invention, the organic-inorganic complex copolymer emulsion is preferably an aqueous emulsion resin containing an acrylic monomer and a monomer containing an alkoxy silyl group or an epoxy silyl group, and synthesized to be siloxane crosslinked in the acrylic main chain. The silyl groups in the main chain react with water during emulsion polymerization to hydrolyze to form silanol, which is then condensed to crosslink into stable siloxane bonds. The crosslinking proceeds at room temperature and the bonding strength of the siloxane bond is 443KJ / mol, which is comparable to 484KJ / mol of the carbon-fluorine bonding strength of the fluorocarbon resin. The organic-inorganic composite copolymer emulsion in the present invention preferably has a glass transition temperature (Tg) of 25 to 45 ℃ for better fouling resistance. If the glass transition temperature is lower than 25 ℃ can be well polluted by the low glass transition temperature due to the contamination source, if the glass transition temperature is higher than 45 ℃ may cause cracks of the coating film and a large amount of solvent is required to solve this problem.

In the present invention, the organic-inorganic composite copolymer emulsion contains 40 to 60% by weight in the coating composition. When the organic-inorganic composite copolymer emulsion is included in less than 40% by weight in the present invention, the adhesion and durability of the coating film may be reduced, and when included in excess of 60% by weight, the coating film may be too flexible or may cause problems such as peeling.

In the present invention, the organic-inorganic complex copolymer emulsion preferably contains 40 to 50% by weight of solids in the emulsion. If the organic-inorganic composite copolymer emulsion of the present invention contains less than 40% by weight of solids, there may be a constraint on the paint formulation design, and if it contains more than 50% by weight, there may be a problem in the stability of the emulsion itself. .

In the organic-inorganic complex copolymer emulsion of the present invention, for example, methyl methacrylate, butyl methacrylate, butyl acrylate, cyclohexane methacrylate, methacrylic acid or mixtures thereof may be used, but the present invention is not limited thereto. It is not. In the organic-inorganic composite copolymer emulsion of the present invention, the monomer containing the alkoxy silyl group or the epoxy silyl group may be, for example, epoxysilane, methacryloxysilane, methyltrimethoxysilane, methacryloxypropyltrimethoxysilane or mixtures thereof. May be used, but is not limited thereto.

The water-soluble topcoat according to the present invention can be significantly improved weatherability compared to the conventional oil paint by using an organic-inorganic complex copolymer emulsion prepared by copolymerizing an acrylic monomer having excellent weather resistance and a monomer containing an alkoxy silyl group as a binder. The coating film may be hydrophilized to impart fouling resistance. At the same time, the coating film is flexible and strong due to its large molecular weight compared to the oil-based acrylic resin, and thus has excellent durability. In addition, it is very eco-friendly because it can minimize the volatile organic compounds.

In the present invention, the extender pigment is included in the coating composition 5 to 20% by weight. In the present invention, when the extender pigment is included in less than 5% by weight, the hardness of the coating film may be lowered. If it is included in an amount exceeding 20% by weight, the adhesion may be slightly lowered or the cured coating film may cause microcracks, which may adversely affect the water resistance. Can be.

In the present invention, the extender pigment is, for example, barium sulfate, calcium carbonate, silica, dolomite, talc, barium sulfate, kaolin, mica, wollastonite, chlorite, aluminum silicate, and aluminum hydroxide, which are generally used in water-soluble topcoats. Side may be used, but is not limited thereto. These can be used individually or in mixture for expression of hardness, physical property, etc. of a coating film.

In the present invention, the colored pigment is included in the coating composition 1 to 20% by weight. In the present invention, when the pigment is contained in less than 1% by weight, there may be a problem of concealment, and when included in excess of 20% by weight may have a problem of lowering the coating properties and cost.

In the present invention, the colored pigment may be, for example, titanium oxide, carbon black, phthalocyanine, iron oxide, and the like, which are generally used in water-soluble topcoats, but are not limited thereto. These may be used alone or in combination for color development of the coating.

In the present invention, the film forming aid can improve the adhesion by helping the fusion of the binder when the coating film is formed to make the coating film more dense and improve the wetting efficiency on the substrate. In addition, the minimum coating film formation temperature of the emulsion binder is lowered to help form the coating film of the water-soluble paint at a low temperature. In the present invention, the film-forming agent is contained in 3 to 10% by weight in the coating composition. In the present invention, when the film forming aid is included in less than 3% by weight may be poor coating film formation at low temperatures, when contained in more than 10% by weight may be very slow drying rate.

In the present invention, the film preparation may be used, for example, Eastman's Texanol (trade name), Dow's Butyl carbitol (trade name), Butyl Cellosolve (trade name) and the like, but is not limited thereto.

In the present invention, water is used as the main solvent of the binder. Water acts as a solvent for the dispersion medium or various compounds of each particle in the paint, and is also used as a diluent when added to the paint. In the present invention, the water is included 5 to 40% by weight in the coating composition. Water used as the main solvent is a very important factor for the environmentally friendly paints of the present invention. In the present invention, it is preferable to use fresh water or deionized water.

The water-soluble topcoat composition of the present invention may further include various additives as necessary. For example, a dispersant and a surfactant may be included for stabilization of the dispersion and compatibility with the emulsion resin. In addition, thixotropic modifiers may be added to prevent sedimentation during paint storage and to ensure workability. Defoamers may be included to prevent bubble stabilization.

Examples of such additives include Disperbyk-190 (trade name) from BYK and Orotan-1850E (trade name) from DOW for the dispersant, and Surfynol 104 from Airproduct, which does not contain alkylphenol ethoxylate (APEO) substances for surfactants. (Trade name), and the thixotropic modifier includes, but is not limited to, Natrosol +330 (trade name) of Hercules.

The water-soluble topcoat composition of the present invention is environmentally friendly with excellent weatherability and stain resistance using water as the main solvent and an organic-inorganic composite copolymer emulsion composed of silicone-modified acrylic as the main binder. In addition, unlike the existing two-component or one-component high-temperature drying paint, it is possible to significantly increase the work efficiency because it is possible to form a coating film of excellent properties in the one-component and room temperature drying conditions. Compared with the conventional water-soluble and oil-soluble external topcoat, it can maintain a beautiful appearance and performance of the coating for a long time and can be said to be a technology suitable for long-term protection of the structure.

Hereinafter, the present invention will be described in detail through examples. However, the embodiments are only illustrated to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Manufacture of wheat base

18 g of water, 1 g of surfactant (APEO free), 0.2 g of thickener, and 0.3 g of antifoam were added to the rust-free container and stirred for about 30 minutes. Then, 0.5 g of a wet dispersant was added and stirred for 5 minutes. Subsequently, 10 g of the extender pigment and 15 g of titanium oxide were slowly added while stirring, and when finished, the rotation speed was increased per minute so that the linear speed of the impeller edge of the stirrer was 18-21 m / s and dispersed for 15 minutes.

Organic-inorganic composite binder manufacturing

First step

In a reactor equipped with a stirrer, a thermometer and a condenser, 50 g of ion-exchanged water, 25 g of methyl methacrylate, 10 g of butyl acrylate, 10 g of butyl methacrylate, 5 g of cyclohexane methacrylate, and SR1025 (α-sulfo-ω- (1- Ammonium salt of (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethane-di-yl), 1 g of Adeka), 0.15 g of potassium persulfate After raising the temperature to 80 ℃ was maintained for about 60 minutes to reach 80 ℃ to prepare a seed (seed) emulsion polymer.

Step 2

500 g of ion-exchanged water, ammonium of SR1025 (α-sulfo-ω- (1- (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethane-di-yl)) Salt, Adeka) 8 g, methyl methacrylate 200 g, butyl acrylate 60 g, butyl methacrylate 60 g, cyclohexane methacrylate 40 g, methacrylic acid 40 g, methyl trimethoxysilane 15 g, methacryloxypropyl trimethoxy 5 g of silane and 1.2 g of potassium persulfate were added thereto to prepare a preemulsion. The preemulsion was continuously added to the reactor for 3 hours, and then maintained at 80 ° C. for 1 hour to prepare a core emulsion.

3rd step

After the holding time was cooled to 40 ℃ and added 4.5g of ammonia water was maintained for 2 hours to prepare a stable core emulsion.

In the same manner as above, a polymer emulsion emulsion polymer having a particle size of 165.5 nm, a solid content of 45.2%, a viscosity of 40 cps and a glass transition temperature of 40 ° C. was obtained.

Example

While slowly stirring the dispersed millbase, 50g of the organic-inorganic composite binder was slowly added thereto, and after stirring for 10 minutes, 5g of a film forming aid was added and stirred for about 10 minutes. As a result, 100 g of water-soluble paint was obtained.

Comparative Example 1

While slowly stirring the dispersed mill base, 50 g of 100% acrylic emulsion was slowly added thereto, followed by stirring for 10 minutes, and then 5 g of a crude film preparation was added and stirred for about 10 minutes. As a result, 100 g of water-soluble paint was obtained.

Comparative Example 2

While slowly stirring the dispersed mill base, 50 g of acrylic urethane dispersion resin was slowly added thereto, followed by stirring for 10 minutes, and then 5 g of crude film preparation was added and stirred for about 10 minutes. As a result, 100 g of water-soluble paint was obtained.

Evaluation of physical properties

After air spray coating the paint prepared in Examples and Comparative Examples 1 and 2 with a dry coating thickness of 80 microns on a 1.5T cold-rolled steel sheet, at least 7 days at a temperature of 23 ± 2 ℃, a relative humidity of 50 ± 10% Dried. At this time, while the inside of the drying chamber is ventilated, strong wind is not directly in contact with the coating film surface.

Weather resistance was observed after 600 hours of QUV-B according to ASTM G53, and the flexibility was according to ASTM D522. Adhesion was evaluated through a forced peel test using a putty knife, and the method used for the discrimination in case of contamination resistance was used. The detailed method is as follows.

First, 10 g of carbon black pigment was soaked in 90 g of water, followed by stirring to prepare a turbid liquid. Thereafter, the source was placed on a coating film prepared using a watch glass or the like, and sealed with an adhesive or a tape to prevent leakage. The specimen was placed in a 50 ° C. oven and left for 1 hour. After the end, the watch glass was removed, washed with running water, scrubbed with a brush, and the decontamination state of the coating film was observed.

As can be seen from the results of Table 2, it was found that the water-soluble topcoat of Example 1 is very excellent in weather resistance and also very excellent in fouling resistance, so that it can maintain a beautiful appearance for a long time when applied to an external top coat.

Claims (7)

(1) (i) preparing a seed emulsion from an aqueous monomer mixture comprising acrylic monomers; (ii) preparing a core emulsion from the aqueous monomer mixture comprising an alkoxy silyl group or an epoxy silyl group containing monomer in the presence of the seed emulsion polymer; And (iii) stabilizing the core emulsion to prepare an organic-inorganic complex copolymer emulsion, and
(2) mixing the prepared organic-inorganic complex copolymer emulsion, extender pigments, colored pigments and film forming aids,
Method for producing a one-component room temperature dry type water-soluble top coat composition. According to claim 1, wherein the one-component room temperature drying type water-soluble topcoat composition is 40 to 60% by weight of the organic-inorganic complex copolymer emulsion, 5 to 20% by weight of the extender pigment, 1 to 20% by weight of the colored pigment, the film 3 to 10% by weight of the preparation and 5 to 40% by weight of water, characterized in that the method for producing a one-component room temperature dry type water-soluble top coat composition. The method of claim 1, wherein the acrylic monomer is selected from methyl methacrylate, butyl methacrylate, butyl acrylate, cyclohexane methacrylate, methacrylic acid and mixtures thereof. Method for producing a topcoat composition. The method of claim 1, wherein the alkoxy silyl group or the epoxy silyl group-containing monomer is selected from epoxysilane, methacryloxysilane, methyltrimethoxysilane, methacryloxypropyltrimethoxysilane and mixtures thereof. Method for producing a one-component room temperature dry type water-soluble top coat composition. According to claim 1, wherein the extender pigment is selected from barium sulfate, calcium carbonate, silica, dolomite, talc, barium sulfate, kaolin, mica, wollastonite, chlorite, aluminum silicate, aluminum hydroxide and mixtures thereof. A method for producing a one-pack room temperature-drying water-soluble top coat composition, characterized by the above-mentioned. The method of claim 1, wherein the colored pigment is selected from titanium oxide, carbon black, phthalocyanine, iron oxide and mixtures thereof. The method of claim 2, wherein the one-component room temperature drying type water-soluble topcoat composition further comprises 1 to 5% by weight of an additive selected from a dispersant, a surfactant, a thixotropic modifier, an antifoaming agent and mixtures thereof, 1 Method for producing a liquid room temperature drying type water-soluble top coat composition.