KR20060078971A - Acryl-amine resin, and resin dispersion and electrodeposited coating composition containing the same - Google Patents

Abstract

The present invention is an acrylic-amine resin prepared by addition reaction of a copolymer of the monomer of formula (1), a hydroxyl group-containing (meth) acrylate and a hydroxyl group-free (meth) acrylate with a secondary amine, an electrodeposition resin dispersion containing the same and the same It relates to the electrodeposition coating composition used.

Where

R and R ₁ are as defined in the specification.

Electrodeposited resins prepared according to the invention have improved weather resistance.

Description

Acryl-amine resin, and resin dispersion and electrodeposited coating composition containing the same}

The present invention relates to a cationic electrodeposition resin capable of improving weather resistance, and more particularly, to an acryl-amine resin that is water-soluble in a cationic form, and to an electrodeposition resin having improved weatherability and corrosion resistance, a resin dispersion containing the same, and an electrodeposition paint. To a composition.

In the case of the conventional polyepoxide-amine addition electrodeposited resin, raw materials of urethane-modified epoxy, polyol, and bisphenols are used as a chain-extension material to secure an appropriate molecular weight. The amines were reacted with each other to prepare an electrodeposition resin to which the polyepoxide-amine addition reaction was carried out. Examples of such reaction products include those for cationic polyepoxide-amine reaction products in US Pat. Nos. 5,492,731, 5,096,556. In the conventional polyepoxide-amine reaction products, there are many advantages in terms of physical properties such as flexibility, adhesion, and rust resistance depending on the properties of the prepared resin, but they have disadvantages such as poor weather resistance and yellowing resistance. In order to overcome the weak weather resistance and yellowing resistance of the electrodeposited resin prepared by the conventional polyepoxide-amine addition reaction, an example of applying an acrylic resin having excellent weather resistance to electrodeposition paint is described in US Patent Nos. 6,476,102 B1, 6,355,351 B1, 6,147,144. , 5,089101. However, the acrylic resins set forth in some of these patents do not have the ability of water solubility of the resins themselves and are partly introduced into the preparation of the polyepoxide-amine resins, so that the polyepoxide-amine resins in the dispersed particles of the final resin dispersion. The acrylic resin and the coexistence form has a problem that the stability and weatherability is weak. In addition, in some patents, there is an example of improving weather resistance by using the prepared acrylic resin as a dispersing resin for producing a pigment paste. However, when these acrylic resins are applied to the pigment paste, problems of storage performance of the pigment paste are caused.

Accordingly, a polyepoxide-amine electrodeposition resin with improved weather resistance is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an acryl-amine electrodeposition resin capable of water solubility and having improved weather resistance of the electrodeposition paint in view of the problems of the above cationic electrodeposition paint.

Another object of the present invention is to provide a cationic electrodeposition resin dispersion containing the acryl-amine electrodeposition resin.

Still another object of the present invention is to provide a cationic electrodeposition coating composition prepared using the above cationic electrodeposition resin dispersion and pigment paste composition.

An object of the present invention for achieving the above object is to produce an acryl-amine resin by addition reaction of a copolymer of the monomer of formula (1), hydroxyl-containing (meth) acrylate and hydroxyl-free (meth) acrylate with secondary amine Is achieved.

[Formula 1]

Where

R represents an alkyl group of 2 to 10 carbon atoms substituted with a diene, methacrylate derivative having 2 to 10 carbon atoms and having one double bond,

R ₁ represents hydrogen or an alkyl group having 2 to 10 carbon atoms.

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

In the present invention, it is preferable that the composition of the acrylic copolymer matches the hydrophilicity and hydrophobicity ratio of the acrylic monomer to be copolymerized in order to ensure dispersibility of the acrylic-amine electrodeposition resin itself.

Among the acrylic monomers used for this purpose, monomers having a hydroxyl group as a hydrophilic group include, but are not limited to, hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy butyl acrylate, hydroxy propyl acrylate, and the like. They are used at 30 to 60% by weight, based on the total monomers used. When less than 30% of the acrylic monomer having a hydroxyl group, which is a hydrophilic group, is used, the hydrophilicity of the acrylic copolymer produced is poor, and the dispersibility of the acrylic-amine electrodeposition resin produced after the amine addition reaction is lowered. Due to the proportion of hydrophilic groups, when the acryl-amine electrodeposition resin is solvated, the average particle size is 60 nm or less, which causes problems in coating film smoothness during electrodeposition coating.

Monomers having no hydroxyl group in the present invention include, but are not limited to, methyl methacrylate, methyl acrylate, ethyl acrylate, lauryl methacrylate, dodecyl methacrylate, and the like. They are used at 30 to 60% by weight, based on the total monomers used. If less than 30% of these monomers are used, the size of the water dispersion particles due to the relatively large number of hydrophilic monomers decreases, resulting in an increase in film coating properties, which causes problems in the smoothness of the coating film. It is a problem.

Monomers of formula (1) in the present invention include glycidyl methacrylate, 2,3-epoxypropyl methacrylate, 1,2-epoxy-7-octene, 1,2-epoxy-5-hexene and 1,2 It is preferable to use one or more selected from -epoxy-9-decene, but is not limited thereto. They are used in 10% to 25% by weight, based on the total monomers used. If less than 10% of these monomers are used, the amount of amine cannot be reached due to the lack of solubilization sites that can react during the addition reaction of amines. This causes problems with dispersibility.

The acrylic monomer can be copolymerized using a radical initiator. The initiators used here are bromine (Br ₂ ), organic peroxide or hydroperoxide initiators, for example benzoyl peroxide, acetyl peroxide, diaryl peroxide, cumyl hydroperoxide, potassium peroxide, azo compounds, for example There is at least one selected from azobisisobutyronitrile (AIBN), and preferably a peroxide initiator such as benzoyl peroxide can be used. The amount of radical initiator used is 1.5 parts by weight to 3 parts by weight based on 100 parts by weight of the total monomers. If the amount of the radical initiator to be used is less than 1.5 parts by weight, the degree of polymerization is poor, and if it is more than 3 parts by weight, dispersibility is reduced due to the increase in molecular weight.

The amines used in the present invention are limited to secondary amines. This is because in the case of primary and ketamine polyvalent amines, gelation occurs upon amine addition reaction with an acrylic copolymer. Preferred examples of the secondary amines may use one or more selected from dimethyl ethanol amine, N-methyl ethanol amine and diethanol amine. The amount of these amines used is 90% to 100% based on the epoxy equivalent weight of the monomers used. If the amount of the amine used is less than 90% based on the epoxy equivalent of the monomer, the dispersibility cannot be secured due to the lack of a water-soluble group, and if it exceeds 100%, the stability of the reactant cannot be secured due to the influence of the unreacted amine.

Electrodeposited resin dispersions can be prepared using electrodeposited resins prepared according to the invention.

The electrodeposition resin dispersion is 15 to 35% by weight of polyepoxide-amine cationic resin, 10 to 25% by weight of polyisocyanate curing agent, 5 to 15% by weight of acrylic-amine electrodeposition resin and 50% by weight of deionized water. 65 weight percent.

The acryl-amine electrodeposition resin contained in the electrodeposition resin dispersion of the present invention is according to the present invention. When the amount is less than 5% by weight, the weatherability of the coating film is poor, and if it exceeds 15% by weight, the dispersibility of the electrodeposition resin dispersion is poor. Not desirable

Examples of cationic synthetic resins formed by addition reactions of polyepoxides and amines contained in the electrodeposition resin dispersions of the present invention are known from US Pat. Nos. 3,962,165, 3,947,358, 3,975,346 and 4,001,156. If it is less than 15% by weight, the coating film riseability of the electrodeposition paint is poor, and the rust resistance and water resistance of the coating film are not preferable.

The polyisocyanate curing agents included in the electrodeposited resin dispersions of the present invention employ fully blocked or partially blocked isocyanates as mentioned in US Pat. No. 4,031,050. For such blocked isocyanates, it is preferable to use a curing agent which is blocked with toluene diisocyanate or methylene diisocyanate with caprolactone, ethanol, butyl carbitol, trimethoxypropanol and the like. If the amount thereof is less than 10% by weight, the curing property of the coating film is lowered, and the baking temperature of the coating film is increased. If the amount is more than 25% by weight, the mechanical properties of the coating film are lowered and the weather resistance of the coating film is not preferable.

The electrodeposition resin dispersion of the present invention may further contain a surfactant and / or a neutralizing agent. As the surfactant, 0.05 to 0.3% by weight of XS-139 or the like of Air Proudct, a butoxy ethanol-based nonionic surfactant, is used. If the amount is less than 0.05% by weight, the water-washing performance is poor during electrodeposition coating, if more than 0.3% by weight there is a problem that a large amount of bubbles are generated. As the neutralized acid used for neutralization, any one or more of inorganic or organic acids such as formic acid, acetic acid, phosphoric acid, lactic acid and sulfamic acid may be used. The amount of neutralized acid used is 0.3% by weight to 2% by weight. If the amount thereof is less than 0.3% by weight, the neutralization rate is insufficient, so that the dispersibility is low. If the amount is more than 2% by weight, the excessive neutralization rate increases, the dispersing particles become smaller and the film film rises, resulting in problems with the smoothness of the film. have.

The method for preparing the electrodeposition resin dispersion of the present invention is as follows:

5 wt% to 15 wt% of acryl-amine electrodeposition resin, 15 wt% to 35 wt% of cationic synthetic resin formed by addition reaction of polyepoxide and amine, 10 wt% to 25 wt% of polyisocyanate curing agent After extraction under low pressure at 650 mmHg to 760 mmHg at a temperature of 100 ° C. to extract a low boiling point solvent such as methyl isobutyl ketone and xylene, an acid is added for neutralization. As an example of a suitable neutralization method, the said electrodeposition resin dispersion liquid can be obtained by adding a neutralizing agent, surfactant, etc., and dropwise addition of deionized water under high speed stirring.

The present invention also provides an electrodeposition paint composition comprising 30% to 45% by weight of electrodeposition resin dispersion, 7% to 15% by weight of pigment paste composition and 40% to 60% by weight of deionized water.                     

The pigment paste composition used in the electrodeposition paint composition according to the present invention is 8% to 25% by weight of the pigment grinding vehicle formed by the addition reaction of the epoxide-amine, and a metal oxide such as dibutyltin as a curing catalyst of the pigment paste composition. It is composed of 0.5% to 3% by weight of oxide, 20% to 40% by weight of pigment components such as titanium dioxide or carbon black, and 20% to 60% by weight of deionized water for the mechanical properties and chemical resistance of the dry coating film. If the pigment grinding vehicle is less than 8% by weight, the dispersibility with the pigment is poor, and if it is more than 25% by weight, the mechanical properties and the chemical resistance are not preferable. If the amount of dibutyltin oxide that is a curing catalyst is less than 0.5% by weight, the curing temperature of the coating film is not increased, and if it is 3% by weight or more, the coating film is hard and mechanical properties are rather deteriorated. Solid content ratio of the pigment / pigment grinding | pulverization vehicle of the said pigment paste is 2.5-5.0. At this time, if the solid content ratio of the pigment / pigment grinding vehicle is less than 2.5, the mechanical properties and chemical resistance of the coating film are deteriorated, and it is not preferable. If the content exceeds 5.0, the properties of the coating film are hard and the mechanical properties are rather deteriorated.

Pigment solid content / electrodeposition resin solid content ratio of the electrodeposition coating composition according to the present invention is 0.25 to 0.45, 0.3 to 0.35 to form a film thickness of 20 to 25 microns at 210 volts when electrodeposition coating, the solid content is 15 to 22% Is preferred.

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

Examples and Comparative Examples

Example 1

Acrylic-amine electrodeposition resins were prepared using the compounds shown in the table below.

After adding methoxy propanol and benzoyl peroxide as a radical initiator to the reactor, the mixture is gradually heated to 80 ° C. under nitrogen atmosphere. After the initiator has completely dissolved, the acrylate monomer mixture is slowly added dropwise into the reactor for 3 hours. After completion of the dropping, the epoxy equivalent is measured to confirm the value in the range of 1600 to 1900. The values of epoxy equivalents 1600 to 1900 are for the purpose of confirming the change of the initial epoxy equivalents measured during the radical reaction, and if the epoxy equivalents are out of the above range, the partial reaction of the epoxy ring by the reaction temperature will be followed. It gives the result of deactivation in phosphorus amine addition reaction. After the completion of the radical reaction, methoxy propanol is added and the nitrogen supply is stopped and oxygen is blown into the reactor while cooling the reactor temperature to 40 ° C. When the reactor temperature reaches 40 ° C, the reactor temperature is gradually raised to 80 ° C. When the reactor temperature reaches 60 ° C diethanol amine is added and the reaction is maintained at 80 ° C 2 hours under oxygen blowing conditions. After completion of the reaction, an acryl-amine electrodeposition resin having an amine value of 14 to 25 and a solid content of 40 to 60 was obtained.

Example 2

Example 2 is another example for preparing acrylic-amine electrodeposition resins.

Except for using lauryl methacrylate instead of methyl methacrylate, the production method is the same as in Example 1.                     

Example 3

Electrodeposited resin dispersions were prepared using the compounds shown in the table below.

After inserting the polyepoxide-amine electrodeposition resin and the blocked polyisocyanate curing agent, the reaction product of Example 1 into the reactor, the solvent was removed in vacuo at 80 ° C., mixed with surfactant XS-139 and formic acid as a neutralized acid, and then desorbed. Ionized water is slowly added dropwise under high-speed stirring to prepare an electrodeposition resin dispersion having a solid content of 35 to 40%.                     

Example 4

Electrodeposited resin dispersions were prepared using the compounds shown in the table below.

It is the same as Example 3 except the ratio of the polyepoxide-amine electrodeposition resin and the reaction product of Example 1.                     

Example 5

Electrodeposited resin dispersions were prepared using the compounds shown in the table below.

Except that the reaction product of Example 2 was applied, and the production method is the same as in Example 4.                     

Comparative Example 1

Electrodeposited resin dispersions were prepared using the compounds shown in the table below.

Except that the acryl-amine electrodeposition resin was not applied, Example 3 and the manufacturing method are the same.                     

Preparation Example 1

The pigment paste compositions according to the invention were prepared using the ingredients and amounts mentioned in the tables below.

The components are mixed together in the order indicated, stirred well and then dispersed up to Hegman No. 6 with a Dispermet SL-703 (BYK) disperser. The solids content of the pigment paste thus obtained is 50 to 60%.

Example 6

This example relates to the preparation of electrodeposition coating compositions for specimen preparation for test evaluation of the present invention.

The solids content of the electrodeposition coating composition constructed by the above examples is 18 to 20% and the ratio of pigment solids / resin solids is 0.3 to 0.35.

Example 7

This example relates to an electrodeposition coating composition for specimen preparation for test evaluation of the present invention.

Except for using the electrodeposition resin dispersion of Example 4, the production method is the same as in Example 6.

The solids content of the electrodeposition paint composition constructed by this example is 18 to 19% and the ratio of pigment solids / resin solids is 0.35 to 0.37.                     

Example 8

This example relates to an electrodeposition coating composition for specimen preparation for test evaluation of the present invention.

Except for using the electrodeposition resin dispersion of Example 5, the production method is the same as in Example 6.

The solids content of the electrodeposition paint composition constructed by this example is 18 to 20% and the ratio of pigment solids / resin solids is 0.35 to 0.4.

Comparative Example 2

This comparative example is a structural example of the electrodeposition coating composition for comparative evaluation of Example 6, Example 7, and Example 8.

Except for using the electrodeposition resin dispersion of Comparative Example 1, and Example 6 are the same.                     

The electrodeposition coating composition prepared above is subjected to electrodeposition coating for 2 minutes at a constant voltage of 210 to 270 volts on a cold rolled steel sheet (9 mm x 20 mm) surface-treated with a zinc phosphate treatment agent. The resulting coating is then washed with water and baked in an oven at 170 ° C. for 30 minutes to obtain a thickness of 20 (± 2) microns. The obtained coating film evaluated saline spray resistance and weather resistance. Physical property test results are shown in Table 1.

1) Measured with a 60-degree glossmeter, the smaller the difference between initial gloss and gloss after UV irradiation

2) The weathering test was performed for 100 hours, and after the experiment, the change of ΔE value of the coating film was confirmed by X-rite. The ΔE value indicates the degree of yellowing. The lower the value, the better.

3) The center of the test specimen was X-cut with a blade, sprayed with 5% aqueous sodium chloride solution at 35 ° C. for 500 hours and 1000 hours, and the peeling width was evaluated by taping the X-cut area with tape after the test was completed.                     

As can be seen in Table 1, the initial gloss and salt water spray test results of Examples 6, 7, and 8 applied with acryl-amine electrodeposition resin were equivalent to those of Comparative Example 2 without acryl-amine electrodeposition resin. It was confirmed that the gloss and ΔE value after the weather resistance evaluation was superior to Comparative Example 2 without acryl-amine electrodeposition resin. In addition, the results of Examples 6 and 7 showed that as the content of acryl-amine electrodeposition resin in the electrodeposition resin dispersion increases, showing a relatively good result in the ΔE value and gloss after weathering evaluation.

As described above, the electrodeposition coating composition to which the polyepoxide-amine electrodeposition resin according to the present invention is applied has no difference in corrosion resistance and appearance and shows excellent results in weatherability evaluation as compared with the electrodeposition coating composition that has been conventionally applied. Able to know.

Improved results can be obtained even when only one component of an electrodeposition coating composition comprising an electrodeposition resin dispersion containing an acryl-amine electrodeposition resin and an electrodeposition resin dispersion containing an acryl-amine electrodeposition resin presented in the present invention is used. In addition, although the present invention has been described 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 (6)

In the electrodeposition resin dispersion containing a polyepoxide-amine cation synthetic resin, a polyisocyanate hardener, and deionized water, 10 to 25% by weight of monomers of formula 1, 30 to 60% by weight of hydroxyl-containing (meth) acrylates and 30 to 60% by weight of hydroxyl-free (meth) acrylates, based on the epoxy equivalent of the monomers 90 to 100% Electrodeposited resin dispersion liquid containing the acryl-amine resin which the secondary amine of was added. [Formula 1

Where R represents an alkyl group having 2 to 10 carbon atoms and substituted with a diene or methacrylate derivative having 2 to 10 carbon atoms and having one double bond, R ₁ represents hydrogen or an alkyl group having 2 to 10 carbon atoms. The method of claim 1. Monomers of formula 1 are glycidyl methacrylate, 2,3-epoxypropyl methacrylate, 1,2-epoxy-7-octene, 1,2-epoxy-5-hexene and 1,2-epoxy-9- Electrodeposited resin dispersion liquid characterized by at least 1 sort (s) selected from decene. The electrodeposition resin dispersion according to claim 1, wherein the secondary amine is at least one selected from dimethyl ethanol amine, N-methyl ethanol amine and diethanol amine. The polyepoxide-amine cationic synthetic resin of 15 to 35% by weight, 10 to 25% by weight of polyisocyanate curing agent, 5 to 15% by weight of acryl-amine resin And 50 wt% to 65 wt% of deionized water. An electrodeposition coating composition comprising 30% to 45% by weight of the electrodeposited resin dispersion according to claim 4, 7% to 15% by weight of the pigment paste composition and 40% to 60% by weight of deionized water. The pigment paste composition of claim 5, wherein the pigment paste composition comprises 8% to 25% by weight of a pigment grinding vehicle, 0.5% to 3% by weight of a curing catalyst, 20% to 40% by weight of a pigment component and 20% to 60% by weight of deionized water. Electrodeposit coating composition comprising a.