KR100413852B1 - One-liquid Type Silicon-Modified and Acryl-based Paint Composition and Method of Preparing the Same - Google Patents

Abstract

Disclosed is a one-component silicone-modified acrylic coating composition having high weather resistance, high hardness, and scratch resistance, and a method of manufacturing the same. The silicone modified acrylic coating composition has an acid value of 5 to 15, an alcohol value of 30 to 100, a weight average molecular weight of 15,000 to 30,000, a nonvolatile content of 40 to 70%, and a silicone modified acrylic resin of 35 to 65 weight having a glass transition temperature of 30 to 70 ° C. It contains 8-18 weight part of melamine resin as a 1st hardening | curing agent, and 0.6-3.0 weight part of block isocyanate resins as a 2nd hardening | curing agent. The coating composition of the present invention does not require the process of mixing the main agent and the curing agent before coating, and there is no problem in storage properties, and has excellent physical properties such as high weather resistance, high hardness, stain resistance, scratch resistance, and chemical resistance.

Description

One-liquid type silicon-modified and acryl-based paint composition and method of preparing the same

The present invention relates to a heat-dried one-component silicone-modified acrylic coating composition having excellent coating properties such as high weather resistance, high hardness, scratch resistance, high gloss, stain resistance, chemical resistance, and the like, which is coated on a building exterior material.

As exterior materials for building exterior materials (outer wall panels, window frames, doors, roofing materials, guard rails, sashes, etc.) made of aluminum and galvanized steel, fluorine paint with excellent weather resistance is used. It is difficult to use universally. In order to cope with this, a high-performance ceramic paint similar to the fluorine paint in terms of physical properties and price competitiveness has been developed, and an acrylic silicone paint is a representative one.

Conventional acrylic silicone paint compositions have been used in a two-part type that separates the main agent and the curing agent due to storage problems due to the chemical structure of the components. Accordingly, there is a disadvantage in that the paint has to be exhausted within a certain time due to the pot life, and the remaining paint must be discarded once it is mixed with the hassle of mixing the main agent and the curing agent during painting.

Looking at the reaction mechanism of the conventional two-component acrylic silicone paint, a siloxane bond is formed by reacting with an amine silane (e.g., γ-aminopropyltrimethoxysilane) in which the hydroxyl group and glycidyl group in the backbone of the acrylic resin used in the subject are used as curing agents. (-Si-O-Si-O-) and cross-linked to form a network structure exhibits properties comparable to the physical properties of fluorine paint. However, the coating composition having such a reaction mechanism is very sensitive to the humidity in the air, and there is a problem in that a coating film defect phenomenon such as cracking of the coating film and gloss reduction due to absorption occurs at a relative humidity of 90% or more. In order to solve this problem, DIPAI Co., Ltd. introduces alternating functional groups of main body and curing agent, that is, acryl monomer (eg n-Butoxymethylacrylamide) and acid having amino group in main acrylic resin backbone, and Glyci as a curing agent. Using a silane having a dill group (Dipia Co., Ltd. trade name; silane), the invention has been applied for a coating composition having no abnormality in coating properties even at a relative humidity of 90% or more. (Korean Patent Application No. 95-16615)

However, although the two-component acrylic silicone paint composition exhibits excellent properties comparable to fluorine paint in terms of coating film properties, the potting time is within 24 hours. The need continues to be demanded.

In the present invention, there is no problem in storage properties by solving the storage problem for the one-component conversion of the acrylic silicone paint composition, and excellent properties such as high weather resistance, high hardness, stain resistance, scratch resistance, chemical resistance, etc. It is an object to provide a one-part coating composition composed of a silicone-modified acrylic resin / melamine / block isocyanate system having.

Another object of the present invention is to provide an easy method for producing the coating composition described above.

In the present invention to achieve the above object

35 to 65 parts by weight of a silicone-modified acrylic resin having a characteristic value of 5 to 15 acid, 30 to 100 alcohol, 15,000 to 30,000 weight average molecular weight, 40 to 70% nonvolatile content, and 30 to 70 ° C glass transition temperature;

8 to 18 parts by weight of the melamine resin as the first curing agent; And

Provided is a one-part silicone-modified acrylic coating composition containing 0.6 to 3.0 parts by weight of a block isocyanate resin as a second curing agent.

In particular, it is preferable that the said melamine resin is resin which has a methoxymethyl and a methoxymethyl- imino functional group, and the said block isocyanate resin is a hexamethylene diisocyanate type resin.

Another object of the present invention described above

Mixing 40 to 60 parts by weight of an acrylic monomer, 15 to 35 parts by weight of a solvent and a reaction initiator to prepare an acrylic resin containing a hydroxyl group and having an alcohol value in the range of 70 to 170;

Dehydrating the obtained acrylic resin with a silicone intermediate having 5 to 20 parts by weight of a hydroxyl group or a methoxy group to prepare a silicone-modified acrylic resin having a siloxane bond; And

It is achieved by a method for producing a one-component silicone modified acrylic coating composition comprising the step of adding a melamine resin as a first curing agent and a block isocyanate resin as a second curing agent to the silicone-modified acrylic resin.

In particular, the silicon intermediate may preferably be used having a molecular weight of 500 to 3,000 and a silicon content in the range of 3 to 20%, and 0.1 to 3 parts by weight of an aromatic sulfonic acid or phosphoric acid reaction catalyst upon addition of the curing agent. It is also preferred to add.

Hereinafter, the present invention will be described in more detail.

The silicone-modified acrylic resin, which is a main resin, contains a hydroxyl group through a first reaction, and prepares an acrylic resin having an aric backbone structure, and then bonds a siloxane through a secondary reaction with a silicon intermediate having a hydroxyl group or a methoxy group. It was prepared in such a way as to have (-Si-O-Si-O-). The silicon intermediate used in the secondary reaction was used within the range of 5 to 20 parts by weight relative to the total weight.

The acrylic resin is synthesized by using the acrylic monomer commonly used in the first reaction so that the alcohol value is in the range of 70 to 170. As the general acrylic monomer, methyl methacrylate, methyl acrylate, ethyl acrylate, styrene, 2-ethylhexyl acrylate, normal-butyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid, acrylic acid and the like can be used.

Silicone intermediates containing a hydroxyl group added to the secondary reaction may be Z-6018 (trade name) resin of Dow Corning (USA) and FM-4411 (trade name) resin of Chisso (USA). As the silicone intermediate to be contained, KR-9218 (trade name) resin of Shin-Etsu (Japan) and TRS-165 (trade name) resin of Toshiba (Japan) can be used.

Hereinafter, the manufacturing method of the coating composition according to the present invention will be described in more detail.

First, high boiling point solvents such as xylene, cellulose acetate, and cocosol-100 are selected alone or as a mixed solution, and 15 to 35 parts by weight are put in a synthetic flask and heated to 130 to 150 ° C. Here, a mixture of 40 to 60 parts by weight of the selected acrylic monomer and 0.5 to 2.0 parts by weight of an organic peroxide radical initiator such as benzoyl peroxide and t-butyl peroxyoctoate is added dropwise at a uniform rate over 2 to 5 hours.

After dropping, the reaction was carried out for 30 to 60 minutes, and then 0.1 to 0.4 parts by weight of the organic peroxide initiator was added once to three times, followed by the holding reaction for 60 to 120 minutes.

After the fat and oil reaction, 0.05 to 0.1 parts by weight of an organic titanium compound such as tetra isopropyl titanate and tetra butyl titanate, 5 to 20 parts by weight of silicon intermediate, and 5 to 10 parts by weight of toluene were added and dehydrated over 90 to 150 minutes. The reaction is carried out to produce a silicone-modified acrylic resin.

Toluene used in the secondary reaction is used as a reflux solvent to remove water generated in the reaction and is not included in the final result. Through the reaction with the silicon intermediate to produce a silicone-modified acrylic resin having a characteristic value of 5 to 15 acid, 30 to 100 alcohol, 15,000 to 30,000 weight average molecular weight, 40 to 70% nonvolatile content, 30 to 70 ℃ glass transition temperature. do.

A silicone-modified acrylic resin was prepared according to the above-described method, and the results on the raw materials used and the amount thereof added, the physical properties of the silicone-modified acrylic resin obtained, and the like are shown in Table 1 below. The unit with respect to the addition amount of each raw material is a weight part.

Synthetic resin Resin I Resin II Resin III Xylene Cellulose Acetate Cosol-100methyl methacrylate styrene 2-ethylhexyl acrylate isobutyl methacrylate ethylhexyl methacrylate 2-hydroxyethyl methacrylate methyl methacrylate t-butylperoxy octoate xylene t Butyl peroxy octoate benzoyl peroxide tetraisopropyl titanate Z-6018FM-4411 toluene 151011.452262--9.50.5250.2-0.110-10 2515-255--12.5100.751.755-0.150.15-7.35 2015-30--12.5-50.51.2550.15-0.1-2.57.25 Sum 103.75 107.5 99.25 Nonvolatile matter (%) Viscosity (Gardner) Alcohol value (OH value) 58.5W-40 50.0U + 59 53X-43

8 to 18 parts by weight of the first curing agent and 0.3 to 3 parts by weight of the second curing agent are added to 35 to 65 parts by weight of the silicone-modified acrylic resin thus prepared to prepare a one-component resin.

When the amount of the silicone-modified acrylic resin is less than 35 parts by weight, it is not preferable to reduce weather resistance and yellowing during high temperature drying, and when the amount of the silicone-modified acrylic resin exceeds 65 parts by weight, it is difficult to control the non-volatile content and coating workability of appropriate paints Therefore, its amount is to be in the above range.

Although melamine resin was used as a 1st hardening | curing agent, what has a methoxymethyl and a methoxymethyl- imino functional group is preferable. Specifically, Cyyana303, 327, 325 manufactured by Cyanamid (USA) was used.

The amount of the first curing agent is 8 to 18 parts by weight. If the amount of the first curing agent is less than 8 parts by weight, the crosslinking density decreases, which is not preferable because the scratchability, chemical property, and hardness are weakened. The impact resistance is lowered due to the increased cracking property of the coating film, and the storage stability is also unfavorable.

The mixing ratio with the silicone-modified acrylic resin prepared according to the method of Table 1 above was applied in a ratio of 6/4, 7/3, and 8/2 (silicone-modified acrylic resin / melamine resin) relative to the nonvolatile content. Curing with a silicone modified acrylic resin / melamine resin system results in hardening of the coating properties, indicating physical properties that are vulnerable to impact resistance and flex resistance.

Therefore, to compensate for this, a block isocyanate is introduced as a second curing agent. It is preferable for the hexamethylene diisocyanate type. Specifically, Desmodur-3175 manufactured by Bayer (Germany) was used. The amount of the block isocyanate is in the range of 0.6 to 3 parts by weight based on the total weight of the silicone-modified acrylic resin / melamine resin in consideration of storage properties. If the amount of the second curing agent is less than 0.6 parts by weight, the impact resistance is lowered due to lack of flexibility of the coating film, and if it is more than 3 parts by weight, the storage stability is lowered, which is not preferable.

In order to proceed smoothly during heat curing, 0.1 to 3 parts by weight of strongly acidic aromatic sulfonic acid or phosphoric acid compound is used as a reaction catalyst.

Table 2 below shows the type and content of each component when prepared as a one-part coating material using a silicone-modified acrylic resin, a main resin, and a melamine resin and a block isocyanate resin used as a curing agent. Units in the table are parts by weight.

Example 1 Example 2 Example 3 Organic solvents 8.33 8.33 8.33 Resin I Resin II Resin III 60-- -60- --60 Ceramic pigment 25 25 25 Melamine resin 15.2 13.1 10.9 Block Isocyanate Resin 2 2 2 additive* 4.2 4.2 4.2 Reaction catalyst 0.15 0.15 0.15 Sum 114.88 112.78 110.58

(* Additives include dispersant, sedimentation inhibitor, UV stabilizer)

The coating composition according to each example shown in Table 2 was prepared in the following manner. Firstly, a part of the solvent, a part of the silicone-modified acrylic resin, a whole amount of pigment, and a dispersant are mixed and dispersed to a particle size of 7 microns or more. A one-part coating composition was prepared.

In order to compare the physical properties and shelf life with the two-component acrylic silicone coating composition, the characteristics of the coating compositions in the patent application filed by Paint Ink Co., Ltd. were compared.

For evaluation of physical properties, the coating composition of the present invention and the coating composition of the comparative example were coated with a dry coating thickness of 25 to 35 microns on a galvanized steel sheet coated with a thickness of 10 microns. Drying conditions were 15 minutes at 180 degreeC.

Table 3 below shows the physical property evaluation results for the coating film prepared using each coating composition.

Property item Experiment method Example 1 Example 2 Example 3 Comparative Example * Promoted weather resistance (%) WOM2000hrs 95 96 95 over 90 QUV2000hrs 97 97 96 over 90 Pencil hardness Mitsubishi pencil 4H- 4H- 4H 4H Salt water spray resistance 5% NaCl, 35 ℃ 500hrs Good Good Good Good Boiling water resistance 6hrs impregnation in boiling water Good Good Good Good Impact resistance (cm) 300gr × 10mm, 1/2 " 20 20 20 20 Adhesion 1mm crosscut, 100/100 100/100 100/100 100/100 100/100 Alkali resistance 5% NaOH, 24hr spot Good Good Good Good Acid resistance 5% H ₂ SO ₄ , 24hr spot Good Good Good Good Solvent resistance MEK rubbing Episode 100 100 times 100 times 100 times 100 times Water resistance 40 ℃, 500hrs Good Good Good Good Repaintable 1mm crosscut, 100/100 100/100 100/100 100/100 100/100 Polish (60 °) 93 89 87 88 Storability ** 60 ℃, 336hrs Good Good Good Gelling, coagulation

* A comparative example is for the case of using the two-component acrylic silicone coating composition disclosed in Korea Patent Application No. 95-16615 filed by Korea Paint Ink Co., Ltd.

** Storability was judged to be good when the viscosity was changed within 70 ± 5Ku even after storage at the initial viscosity of 70Ku.

As can be seen from the above evaluation of the physical properties, the coating composition of the present invention is a one-part type and a coating film equivalent to or higher than the properties of high weather resistance, high hardness, scratch resistance, chemical resistance, etc., which are characteristic of the conventional two-component acrylic silicone coating composition. It has excellent properties and no problem in storage.

As described above, the one-component silicone-modified acrylic coating composition of the present invention does not have to mix the main agent and the curing agent during the painting work by one-component molding of the conventional two-component acrylic silicone coating composition, and the coating according to the pot life of the two-component coating. The work time restrictions were removed.

The coating composition of the present invention exhibits excellent coating properties such as high weather resistance, high hardness, scratch resistance, and chemical resistance of conventional two-component acrylic silicone coating compositions. In addition, the coating composition of the present invention has no problem in shelf life.

Although the present invention has been described above according to an embodiment of the present invention, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit of the present invention.

Claims (10)

An acid value of 5 to 15, an alcohol of 30 to 100, a weight average molecular weight of 15,000 to 30,000, a nonvolatile content of 40 to 70%, a glass transition temperature of 30 to 70 ° C, and 35 to 65 parts by weight of a silicone-modified acrylic resin having a siloxane bond; 8 to 18 parts by weight of a melamine resin having methoxymethyl and methoxymethyl-imino functional groups as the first curing agent; And 1-part silicone modified acrylic coating composition containing 0.6-3.0 weight part of block isocyanate resins which are hexamethylene diisocyanate type resin as a 2nd hardening | curing agent. delete delete The coating composition according to claim 1, further comprising a dispersant, an antisettling agent or an ultraviolet stabilizer. Mixing 40 to 60 parts by weight of an acrylic monomer, 15 to 35 parts by weight of a solvent and a reaction initiator to prepare an acrylic resin containing a hydroxyl group and having an alcohol value in the range of 70 to 170; Preparing a silicone-modified acrylic resin having a siloxane bond by dehydrating 5 to 20 parts by weight of a silicon intermediate having an acrylic resin, a hydroxyl group or a methoxy group, a molecular weight of 500 to 3,000 and a silicon content of 3 to 20%; And A method for producing a one-part silicone modified acrylic coating composition comprising adding a melamine resin as a first curing agent and a block isocyanate resin as a second curing agent to the silicone-modified acrylic resin. The method of claim 5, wherein the acrylic monomer is methyl methacrylate, methyl acrylate, ethyl acrylate, styrene, 2-ethylhexyl acrylate, normal- butyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxy At least one selected from the group consisting of oxyethyl acrylate, methacrylic acid and acrylic acid. The method according to claim 5, wherein the solvent is at least one selected from the group consisting of xylene, cellulsolve acetate and cocozol-100, and the reaction initiator is an organic peroxide radical initiator. The method according to claim 5, wherein an organic titanium compound is further added as a reaction accelerator in the step of producing the silicone-modified acrylic resin. delete The method according to claim 5, wherein 0.1 to 3 parts by weight of an aromatic sulfonic acid or a phosphoric acid reaction catalyst is further added when the curing agent is added.