KR102177966B1 - Aqueous epoxy resin dispersion and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a first modified epoxy resin comprising a unit derived from a first epoxy resin and a unit derived from an anhydride resin; And a second modified epoxy resin comprising a second epoxy resin-derived unit and a polyhydric alcohol-derived unit; containing, a water-soluble epoxy resin dispersion and a method for producing the same.

Description

Water-soluble epoxy resin dispersion and its manufacturing method {AQUEOUS EPOXY RESIN DISPERSION AND MANUFACTURING METHOD THEREOF}

The present invention relates to a water-soluble epoxy resin dispersion and a method for preparing the same.

Epoxy resin easily reacts with amines or acids to form a cured product having a strong cured structure.In particular, bisphenol-A epoxy resin has excellent chemical resistance, heat resistance, hardness and flexibility due to its structural characteristics, so it is applied in various industrial fields. have. Specifically, epoxy resin is used as a main component of a main component such as heavy anticorrosive paints and plant paints in the paint field, and it is used together with an amine or amide curing agent to exhibit very excellent performance as a paint.

Meanwhile, oil-soluble resins that have been conventionally used in various industrial fields are being replaced by water-soluble resins due to continuous environmental regulations. According to these changes, research on methods that can be used by water-soluble epoxy resins is continuing. Specifically, various methods have been proposed, such as an epoxy resin dispersed using an emulsifier and a resin in which a portion of the resin is substituted with a water-soluble functional group and dispersed in water. However, conventional dispersions obtained by dispersing a bisphenol-A epoxy resin have difficulty in satisfying the physical properties required in the market. Accordingly, many studies are being conducted to improve the physical properties of the water-dispersible resin to a level equivalent to that of the existing oil-soluble resin.

In this regard, Japanese Patent No. 4,890,688 (Patent Document 1) includes polyalkylene glycol-modified epoxy resins obtained by reacting polyalkylene glycols, bisphenol-type epoxy resins, active hydrogen-containing compounds, and isocyanate-based compounds; Epoxy group-containing resin; And a modified epoxy resin obtained by reacting a hydrazine derivative. However, the water-soluble epoxy resin dispersion of Patent Literature 1 has a problem of high viscosity after water dispersion and lack of appearance characteristics and rust prevention properties of the resulting coating film.

Therefore, while the prepared epoxy resin dispersion satisfies the physical properties required by the market, such as rust prevention and impact resistance, research and development on water-soluble and eco-friendly epoxy resin dispersions are required.

Japanese Patent Registration No. 4,890,688 (Publication date: 2011.12.22.)

The present invention provides an epoxy resin dispersion that is excellent in physical properties such as rust prevention and impact resistance, and is water-soluble and eco-friendly, and a method for preparing the same.

The present invention relates to a first modified epoxy resin comprising a unit derived from a first epoxy resin and a unit derived from an anhydride resin; And a second modified epoxy resin comprising a unit derived from a second epoxy resin and a unit derived from a polyhydric alcohol; containing a water-soluble epoxy resin dispersion.

In addition, the present invention comprises the steps of preparing a first modified epoxy resin by reacting a first epoxy resin and an anhydride resin; Reacting a second epoxy resin and a polyhydric alcohol to prepare a second modified epoxy resin; And it provides a method for preparing a water-soluble epoxy resin dispersion comprising; and dispersing the first modified epoxy resin and the second modified epoxy resin in water.

The water-soluble epoxy resin dispersion according to the present invention includes an alcohol-derived unit having excellent flexibility and a second modified epoxy resin including an epoxy-derived unit, and has excellent impact resistance. In addition, the water-soluble epoxy resin dispersion is water-soluble, environmentally friendly, and has excellent rust prevention, adhesion, and water resistance.

Hereinafter, the present invention will be described in detail.

In the present invention, the'weight average molecular weight' of the resin can be measured by a method well known in the art, for example, it can represent a value measured by the method of GPC (gel permeation chromatograph). In addition, functional groups such as'acid value' and'hydroxyl value' may be measured by methods well known in the art, and may represent values measured by, for example, titration.

Water-soluble epoxy resin dispersion

The water-soluble epoxy resin dispersion according to the present invention includes a first modified epoxy resin and a second modified epoxy resin.

First modified epoxy resin

The first modified epoxy resin is the main resin of the water-soluble epoxy resin dispersion, and the first modified epoxy resin includes a unit derived from the first epoxy resin and a unit derived from an anhydride resin. For example, the first modified epoxy resin may be prepared by reacting the first epoxy resin and an anhydride resin, and each unit constituting the first modified epoxy resin will be described in more detail below.

<1st epoxy resin>

The first epoxy resin is a resin that forms the basic skeleton of the first modified epoxy resin, for example, a bisphenol-A epoxy resin, a cresol-modified epoxy resin, or an isocyanate-modified epoxy resin, and another example is a bisphenol-A type epoxy. It can be resin. The bisphenol-A epoxy resin may be commercially available products such as Kukdo Chemical's YD-128 (epoxy equivalent: 190 g/eq) and YD-011 (epoxy equivalent: 475 g/eq). When a bisphenol-A epoxy resin is used as the first epoxy resin, chemical resistance, heat resistance, hardness, and flexibility of a coating film formed using the prepared water-soluble epoxy resin dispersion may be further improved.

The first epoxy resin may have an epoxy equivalent of 100 to 700 g/eq, for example, 150 to 600 g/eq, or 200 to 450 g/eq. When the epoxy equivalent of the first epoxy resin is less than 100 g/eq, there is a problem of poor water resistance and rust prevention, and when it exceeds 700 g/eq, when applied as a water dispersion resin, water dispersibility is poor and rust prevention is poor There is.

The first epoxy resin may adjust the epoxy equivalent within the above range by appropriate means as needed. For example, when using a bisphenol-A epoxy resin as the first epoxy resin, the bisphenol-A epoxy resin is mixed with bisphenol-A. By reacting, the epoxy equivalent can be adjusted within the above range. In addition, the epoxy equivalent of the first epoxy resin may be adjusted by reacting two or more epoxy resins having different epoxy equivalents with each other.

<Anhydrous resin>

The anhydride resin acts as a bridge (branch) to the first epoxy resin to impart flexibility to the first modified epoxy resin.

The anhydride resin may be a resin prepared by reacting a cyclic anhydride with an alcohol to open the cyclic structure of the cyclic anhydride.

At this time, the cyclic anhydride may be an alicyclic or aromatic anhydride, for example, phthalic anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride Ride, methylhexahydrophthalic anhydride, maleic anhydride, succinic anhydride, trimellitic anhydride, and the like.

In addition, the alcohol may be a poly alcohol containing two or more hydroxyl groups, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol and methyl polypropylene glycol.

The alcohol may have a weight average molecular weight (Mw) of 400 to 10,000 g/mol, such as 500 to 6,000 g/mol, or 600 to 1,000 g/mol. When the weight average molecular weight of the alcohol is less than 400 / mol, the prepared resin and coating film become too soft (Soft) and the impact resistance is poor, and when it exceeds 10,000 g/mol, the resin and coating film become too hard (hard) appearance characteristics There is a problem of this deterioration.

The anhydride resin may have a hydroxyl value (OHv) of 10 to 100 mgKOH/g, for example, 10 to 60 mgKOH/g. When the hydroxyl value of the anhydride resin is out of the above range, rust prevention property may be deteriorated.

In addition, the anhydride resin may have an acid value (AV) of 100 to 300 mgKOH/, for example, 120 to 160 mgKOH/g. When the acid value of the anhydride resin is out of the above range, adhesion may decrease.

The anhydride resin may have a weight average molecular weight (Mw) of 200 to 2,000 g/mol, for example, 600 to 800 g/mol. When the weight average molecular weight of the anhydride resin is out of the above range, workability may be poor and impact resistance may be poor.

As described above, the first modified epoxy resin of the present invention may be prepared by reacting the first epoxy resin and the anhydride resin, in which case, 100 parts by weight of the first epoxy resin and the anhydride resin 10 to 50 It is possible to react in parts by weight. When the content of the anhydride resin is out of the above range, the molecular weight of the prepared first modified epoxy resin becomes too large, resulting in poor water dispersion process and resin storage, and when applied to a paint, appearance characteristics deteriorate and workability (Sagging) This can be bad.

In addition, the first modified epoxy resin may have an epoxy equivalent of 200 to 850 g/eq, for example, 290 to 800 g/eq, or 290 to 650 g/eq. When the epoxy equivalent of the first modified epoxy resin is within the above range, it is difficult to proceed with the water dispersion process because the viscosity of the resin is too high or too low, and even if it is dispersed in water, it is possible to prevent the problem of lack of rust prevention and impact resistance of the prepared dispersion. can do.

Second modified epoxy resin

The second modified epoxy resin is a resin that acts as an emulsifier in the water-soluble epoxy resin dispersion, and while improving the dispersibility of the first modified epoxy resin, the flexibility and impact resistance of the coating film formed using the water-soluble epoxy resin dispersion of the present invention , Rust prevention, workability (sagging) and improve the appearance characteristics.

The second modified epoxy resin includes a unit derived from a second epoxy resin and a unit derived from a polyhydric alcohol. For example, the step of preparing an intermediate reactant by reacting the second modified epoxy resin with a polyhydric alcohol and an anhydride; And reacting the intermediate reactant with the second epoxy resin, and each unit constituting the second modified epoxy resin will be described in more detail below.

<2nd epoxy resin>

An example of the second epoxy resin may be a bisphenol A type epoxy resin, a novolak type epoxy resin, or an acrylic modified epoxy resin, and another example may be a bisphenol A type epoxy resin or a noblock type epoxy resin. As a commercial product of the above epoxy resin, Dow Chemical's DEN-431 (epoxy equivalent: 175 g/eq), Kukdo Chemical's YDPN-636 (epoxy equivalent: 180 g/eq), YDPN-638 (epoxy equivalent: 180 g/eq) , YD-011 (epoxy equivalent: 475 g/eq) and the like can be used.

In addition, the second epoxy resin may have an epoxy equivalent of 50 to 500 g/eq, such as 150 to 480 g/eq. When the epoxy equivalent of the second epoxy resin is less than 50 g/eq, the appearance characteristics of the produced coating film are deteriorated, and when it exceeds 500 g/eq, the water dispersion may be poor and the size of the particles dispersed in the dispersion may be poor. have.

<Additional alcohol>

The polyhydric alcohol is a compound having two or more hydroxyl groups, and may be, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, methyl polypropylene glycol, polyethylene oxide, and the like. Specifically, the polyhydric alcohol may include polyethylene glycol.

In addition, the polyhydric alcohol may have a weight average molecular weight of 800 to 8,000 g/mol, for example, 1,000 to 8,000 g/mol. When the weight average molecular weight of the polyhydric alcohol is out of the above range, the emulsification power of the prepared resin decreases, resulting in poor dispersion stability upon water dispersion, and the prepared coating film may have poor appearance characteristics and workability (sagging).

<anhydride>

The anhydride may be an aromatic or alicyclic anhydride. For example, the anhydride is phthalic anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, maleic anhydride It may include at least one selected from the group consisting of ride, succinic anhydride and trimellitic anhydride. For example, the anhydride may be tetrahydrophthalic anhydride, but is not limited thereto.

As described above, the second modified epoxy resin of the present invention comprises the steps of preparing an intermediate reactant by reacting a polyhydric alcohol and an anhydride; And reacting the intermediate reactant with the second epoxy resin; wherein the polyhydric alcohol and the anhydride may react in a molar ratio of 1: 0.5 to 2, and the intermediate reactant and The second epoxy resin may react at a molar ratio of 1: 0.5 to 1.5.

When the reaction molar ratio of the polyhydric alcohol and the anhydride is out of the above range, the storage property of the prepared water-soluble epoxy resin dispersion is deteriorated, and appearance characteristics and sagging may be poor when applied as a paint. In addition, when the reaction molar ratio between the intermediate reactant and the second epoxy resin is out of the above range, the emulsification power of the prepared water-soluble epoxy resin dispersion decreases, resulting in unstable water dispersion, resulting in poor size of the particles dispersed in the dispersion. have.

The second modified epoxy resin may have an epoxy equivalent of 500 to 11,000 g/eq, for example, 900 to 5,000 g/eq, or 950 to 3,000 g/eq. When the epoxy equivalent of the second modified epoxy resin is out of the above range, the viscosity of the prepared resin may be too high or too low to proceed with the water dispersion process, and even if it is water dispersed, the rust prevention property of the prepared dispersion and There is a problem of insufficient impact resistance.

In addition, the second modified epoxy resin may be included in the dispersion in 5 to 15 parts by weight based on 100 parts by weight of the first modified epoxy resin. For example, the second modified epoxy resin may be included in the dispersion in 7 to 15 parts by weight based on 100 parts by weight of the first modified epoxy resin. When the content of the second modified epoxy resin is outside the above range and contains a trace amount of the second modified epoxy resin, the water dispersion of the prepared resin becomes poor, and when an excessive amount of the second modified epoxy resin is included, the appearance of the coating film And the workability (sagging) of the paint may be deteriorated.

additive

In addition, the water-soluble epoxy resin dispersion may further include one or more additives selected from the group consisting of auxiliary emulsifiers, dispersants, defoaming agents and organic solvents.

The auxiliary emulsifier serves to improve the dispersibility of the first modified epoxy resin and the second modified epoxy resin. In addition, the auxiliary emulsifier is not particularly limited as long as it is an emulsifier typically used in an epoxy aqueous dispersion, and for example, the auxiliary emulsifier may be a nonionic emulsifier. For example, the auxiliary emulsifier may be an ethylene oxide-propylene oxide-ethylene oxide block copolymer (EO-PO-EO block copolymer). Specifically, the auxiliary emulsifier has a weight average molecular weight of 1,000 to 4,000 g/mol, or 2,000 to 3,000 g/mol of propylene oxide (PO), and a weight average molecular weight of ethylene oxide (EO) of 2,000 to 10,000 g/mol, Alternatively, 4,000 to 8,000 g/mol of ethylene oxide-propylene oxide-ethylene oxide block copolymer may be used. When the ranges of the weight average molecular weight of ethylene oxide (EO) and the weight average molecular weight of propylene oxide (PO) of the auxiliary emulsifier are within the above ranges, there is an effect of improving the water dispersion stability of the dispersion containing the same.

Further, commercially available products of the auxiliary emulsifier include Adeka's F-68, F-87, F-88, F-108, F-127, and the like.

In this case, the total amount of the second modified epoxy resin and the auxiliary emulsifier may be 7 to 15 parts by weight based on 100 parts by weight of the first modified epoxy resin. When the total amount of the auxiliary emulsifier is within the above range, the water dispersion of the first modified epoxy resin is well performed, and a problem in which the application field is limited due to insufficient water resistance of the prepared dispersion can be prevented.

The dispersant serves to improve dispersion stability of the dispersion by improving the dispersibility of various components in the dispersion. In addition, the dispersant may be used without particular limitation as long as it is a conventional dispersant or dispersion stabilizer that can be used in the epoxy aqueous dispersion. For example, commercially available products of the dispersant include Adeka's Pluronic L-34, 44, and 64.

In addition, the dispersant may be included in the dispersion in an amount of less than 1 part by weight or less than 0.5 part by weight based on 100 parts by weight of the first modified epoxy resin. When the content of the dispersant is within the above range, it is possible to prevent the problem of occurrence of cratering on the surface or insufficient leveling property when the dispersion liquid containing the same is applied thinly.

In addition, the antifoaming agent serves to suppress the generation of bubbles generated during the preparation of the dispersion. Further, the antifoaming agent may be used without particular limitation as long as it is a conventional antifoaming agent that can be used in an epoxy aqueous dispersion. For example, commercial products of the antifoaming agent include BYK's Byk-011, Byk-014, Byk-018, Byk-024, Byk-1710, Byk-1719, and the like.

Furthermore, the organic solvent serves to adjust the viscosity of the water-soluble epoxy resin dispersion. The organic solvent is not particularly limited as long as it is a solvent capable of diluting the epoxy resin, but, for example, butyl cellosolve, 1-methoxy-2-propanol, dipropylene glycol-n-butyl ether, isopropyl alcohol, ethylene glycol , Taxanol, butyl carbitol, etc. are mentioned.

The water-soluble epoxy resin dispersion may contain 50 to 75% by weight of solids based on the total weight of the dispersion. For example, the water-soluble epoxy resin dispersion may contain 50 to 70% by weight, 50 to 65% by weight, or 50 to 60% by weight of solids based on the total weight of the dispersion.

In addition, the water-soluble epoxy resin dispersion may have a viscosity of 10 to 15,000 cps at 25°C. For example, the water-soluble epoxy resin dispersion may have a viscosity at 25° C. of 10 to 1,000 cps, or 30 to 800 cps, and as another example, 50 to 500 cps.

Furthermore, the water-soluble epoxy resin dispersion may have an epoxy equivalent of 250 to 2,500 g/eq. For example, the water-soluble epoxy resin dispersion may have an epoxy equivalent of 350 to 2,000 g/eq, or 800 to 1,700 g/eq.

The water-soluble epoxy resin dispersion as described above is environmentally friendly because it is water-soluble, and has excellent rust prevention, adhesion, and water resistance.

Method for preparing water-soluble epoxy resin dispersion

The method of preparing a water-soluble epoxy resin dispersion according to the present invention comprises the steps of preparing a first modified epoxy resin by reacting a first epoxy resin and an acid anhydride resin; Reacting a second epoxy resin and a polyhydric alcohol to prepare a second modified epoxy resin; And dispersing the first modified epoxy resin and the second modified epoxy resin in water.

Preparing the first epoxy resin

In this step, a first modified epoxy resin is prepared by reacting the first epoxy resin with an anhydride resin.

The first epoxy resin is as described in the first epoxy resin of the water-soluble epoxy resin dispersion. For example, the first epoxy resin may be prepared by mixing and reacting two or more epoxy resins having different epoxy equivalents in order to control the epoxy equivalent. Specifically, the first epoxy resin is a mixture of two or more epoxy resins having different epoxy equivalents, or a mixture containing an epoxy resin and bisphenol-A, and a catalyst, and the mixture is heated to 120 to 150° C. and then reacted for 1 to 5 hours. Can be prepared by More specifically, the first epoxy resin is a mixture of two or more epoxy resins having different epoxy equivalents, or a mixture containing an epoxy resin and bisphenol-A, and a catalyst, and the temperature is raised to 130 to 140° C. for 2 to 4 hours. It can be prepared by reacting.

At this time, the mixing ratio of two or more types of epoxy resins having different epoxy equivalents, and the mixing ratio of the epoxy resin and bisphenol-A may be appropriately adjusted according to the target epoxy equivalent. In addition, the catalyst is not particularly limited as long as it is a catalyst that can be applied to an epoxy resin, but may be, for example, ethyltriphenylphosphonium bromide.

The anhydride resin may be prepared by reacting alcohol and cyclic anhydride. At this time, the alcohol and cyclic anhydride are as described in the anhydride resin of the first modified epoxy resin.

Specifically, the anhydride resin may be prepared by mixing the alcohol and cyclic anhydride in a molar ratio of 1: 1 to 3, raising the temperature to 120 to 150 °C, and reacting for 1 to 7 hours. More specifically, the anhydride resin may be prepared by mixing the alcohol and cyclic anhydride in a molar ratio of 1: 1 to 2.5, raising the temperature to 130 to 140°C, and reacting for 4 to 7 hours.

In the first modified epoxy resin, the first epoxy resin and an anhydride resin are mixed in a weight ratio of 100:10 to 50, and the temperature is raised to 120 to 160°C, or 135 to 145°C, and then reacted until the epoxy equivalent is close to the theoretical value. I can. At this time, the theoretical epoxy equivalent can be calculated by Equation 1 below.

Preparing a second modified epoxy resin

In this step, a second modified epoxy resin is prepared by reacting a second epoxy resin and a polyhydric alcohol.

Specifically, the step (a) of preparing an intermediate reactant by reacting a polyhydric alcohol and an anhydride; And (b) reacting the intermediate reactant with the second epoxy resin. Specifically, the step (a) of preparing an intermediate reactant by ring-opening an anhydride with a polyhydric alcohol; And (b) preparing a second modified epoxy resin by reacting the intermediate reactant with the second epoxy resin. In this case, the second epoxy resin may be a novolak type epoxy resin.

For example, the step (a) may be performed for 2 to 4 hours after mixing a polyhydric alcohol and an anhydride in a molar ratio of 1: 0.5 to 2 and heating to 120 to 150°C. Specifically, step (a) may be carried out for 2.5 to 3.5 hours after mixing a polyhydric alcohol and an anhydride in a molar ratio of 1: 0.8 to 1.5 and raising the temperature to 130 to 140 °C.

In addition, the step (b) may be carried out until the intermediate reactant and the second epoxy resin are mixed in a molar ratio of 1: 0.5 to 1.5 and heated to 120 to 150° C. until the epoxy equivalent is close to the theoretical value. In this case, the theoretical epoxy equivalent can be calculated by the following equation (2), and the mixture of the following equation (2) is a mixture containing an intermediate reactant and a second epoxy resin.

In addition, the second epoxy resin, polyhydric alcohol, and anhydride are as described in the water-soluble epoxy resin dispersion.

The properties of the second modified epoxy resin prepared as described above are as defined in the second modified epoxy resin of the water-soluble epoxy resin dispersion.

Water dispersing

In this step, the first modified epoxy resin and the second modified epoxy resin are dispersed in water.

Specifically, in this step, 100 parts by weight of the first modified epoxy resin and 5 to 15 parts by weight of the second modified epoxy resin may be mixed, and the viscosity may be increased to a temperature of 10,000 to 30,000 cps, thereby dispersing in water. Specifically, in this step, 100 parts by weight of the first modified epoxy resin and 7 to 15 parts by weight of the second modified epoxy resin may be mixed, and the temperature may be increased to 75 to 95°C so that the viscosity becomes 10,000 to 30,000 cps, thereby dispersing in water. When the water dispersion temperature is within the above range, evaporation of water as a solvent is prevented and the first modified epoxy resin is evenly dispersed.

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

However, these examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

1. Preparation of the second modified epoxy resin

1) Preparation Example 1-1. Preparation of the second modified epoxy resin

In a four-neck round flask, polyethylene glycol (800 g) and tetrahydrophthalic anhydride (40 g) having a weight average molecular weight of 4,000 g/mol were added at a molar ratio of 1:1, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer, and After installing the heater, the temperature was raised to 140° C. at a rate of 20° C. per hour, and then maintained for 3 hours to obtain an intermediate reactant (acid value: 16 mgKOH/g). Thereafter, 123 g of a novolak type epoxy resin (YDPN-638, epoxy equivalent: 180 g/eq) was added to the intermediate reactant, reacted at 130° C. until the epoxy equivalent became 2,500 g/eq, and then cooled to crystallize white. A second modified epoxy resin was obtained.

2) Preparation Example 1-2. Preparation of the second modified epoxy resin

In a four-necked round flask, polyethylene glycol (620 g) and tetrahydrophthalic anhydride (94 g) having a weight average molecular weight of 1,000 g/mol were added at a molar ratio of 1:1, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, After installing a thermometer and a heater, the temperature was raised to 140° C. at a rate of 20° C. per hour and maintained for 3 hours to obtain an intermediate reactant (acid value: 48 mgKOH/g). Thereafter, 287 g of a novolac-type epoxy resin DEN431 (epoxy equivalent: 175 g/eq) was added to the intermediate reactant, reacted at 130° C. until the epoxy equivalent became 970 g/eq, and cooled to crystallize a second white color. An epoxy resin was obtained.

3) Preparation Example 1-3. Preparation of the second modified epoxy resin

In a four-neck round flask, polyethylene glycol (883 g) and tetrahydrophthalic anhydride (17 g) having a weight average molecular weight of 8,000 g/mol were added at a molar ratio of 1:1, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, After installing a thermometer and a heater, the temperature was raised to 140° C. at a rate of 20° C. per hour, and then maintained for 3 hours to obtain an intermediate reactant (acid value: 7 mgKOH/g). Thereafter, 100 g of epoxy resin YD011 (epoxy equivalent: 475 g/eq) was added to the intermediate reactant, reacted at 130° C. until the epoxy equivalent became 10,060 g/eq, and then cooled to crystallize a white second modified epoxy resin. Got it.

2. Preparation of the first modified epoxy resin

1) Preparation Example 2-1. Preparation of anhydrous resin

In a 4-neck round flask, add 800 g of polypropylene glycol with a weight average molecular weight of 800 g/mol and 304 g of tetrahydrophthalic anhydride, and install a nitrogen gas tube, H-type separator, stirrer, thermometer, and heater at 140° C. for 4 hours. The temperature was raised to and maintained for 5 hours. After cooling to 70 ℃ to obtain anhydrous acid.

The prepared anhydrous acid has a hydroxyl value (OHv) of 10 mgKOH/g, an acid value (AV) of 160 mgKOH/g, a weight average molecular weight (Mw) of 600 g/mol, and the viscosity at 25°C was shown as Z3 by Gardner viscosity. .

2) Preparation Example 2-2. Preparation of anhydrous resin

In a four-necked round flask, 660 g of polypropylene glycol and 330 g of tetrahydrophthalic anhydride with a weight average molecular weight of 800 g/mol were added, and a nitrogen gas tube, H-type separation tube, stirrer, thermometer, and heater were installed, and then 140℃ for 4 hours. The temperature was raised to and maintained for 5 hours. After cooling to 70 ℃ to obtain anhydrous acid.

The prepared anhydrous acid has a hydroxyl value (OHv) of 60 mgKOH/g, an acid value (AV) of 120 mgKOH/g, a weight average molecular weight (Mw) of 770 g/mol, and the viscosity at 25°C is determined by Gardner's viscosity. Appeared as Z4+.

3) Preparation Example 3-1. Preparation of the first epoxy resin

To a four-necked flask, 105 g of bisphenol-A and 600 g of Kukdo Chemical's YD-128 (epoxy equivalent: 190 g/eq) were placed, and a nitrogen gas tube, an H-type separator, a stirrer, a thermometer, and a heater were installed. After that, the temperature was raised to 100°C, and when the mixture was completely dissolved, 0.5g of ethyltriphenylphosphonium bromide was added, the temperature was raised to 130°C, and reacted for 3 hours to obtain a first epoxy resin having an epoxy equivalent of 400g/eq. .

4) Preparation Example 3-2. Preparation of the first epoxy resin

To a four-necked flask, 45 g of bisphenol-A and 600 g of Kukdo Chemical's YD-128 (epoxy equivalent: 190 g/eq) were placed, and a nitrogen gas tube, an H-type separation tube, a stirrer, a thermometer, and a heater were installed. After that, the temperature was raised to 100°C, and when the mixture was completely dissolved, 0.5g of ethyltriphenylphosphonium bromide was added, the temperature was raised to 130°C, and reacted for 3 hours to obtain a first epoxy resin having an epoxy equivalent of 220g/eq. .

5) Preparation Example 4-1. Preparation of the first modified epoxy resin

750 g of the first epoxy resin prepared in Preparation Example 3-1 and 100 g of an anhydride resin prepared in Preparation Example 2-1 were put into a four-necked round flask, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer, and a heater were installed. . After that, the temperature was raised to 130℃ at a rate of 20℃ per hour, and the epoxy equivalent was measured once per hour. When the epoxy equivalent reached 630g/eq, the reaction was terminated, cooled to 80℃, and the first modified epoxy resin (epoxy modified with anhydrous acid Resin) was prepared.

6) Preparation Example 4-2. Preparation of the first modified epoxy resin

750 g of the first epoxy resin prepared in Preparation Example 3-1 and 100 g of an anhydride resin prepared in Preparation Example 2-2 were put into a four-necked round flask, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer, and a heater were installed. . After that, the temperature was raised to 130℃ at a rate of 20℃ per hour, and the epoxy equivalent was measured once per hour. When the epoxy equivalent reached 360g/eq, the reaction was terminated, cooled to 80℃, and the first modified epoxy resin (epoxy modified with anhydrous acid Resin) was prepared.

7) Preparation Example 4-3. Preparation of the first modified epoxy resin

750 g of the first epoxy resin prepared in Preparation Example 3-2 and 100 g of an anhydride resin prepared in Preparation Example 2-1 were put into a four-necked round flask, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer, and a heater were installed. . After that, the temperature was raised to 130℃ at a rate of 20℃ per hour, and the epoxy equivalent was measured once per hour. When the epoxy equivalent reached 290g/eq, the reaction was terminated, cooled to 80℃, and the first modified epoxy resin (epoxy modified with anhydrous acid Resin) was prepared.

3. Preparation of water-dispersible epoxy resin

1) Example 1. Preparation of water-soluble epoxy resin dispersion

To 850 g of the first modified epoxy resin of Preparation Example 4-1, 100 g of the second modified epoxy resin prepared in Preparation Example 1-1, 2 g of an auxiliary emulsifier (F108 from Adeka), and 5 g of butyl cellosolve were added, and the temperature was raised to 85°C. Then, the mixture was stirred for 30 minutes to prepare a mixture. Thereafter, 0.08 g of a dispersant (L-64 from Adeka) was added to the mixture, and the mixture was stirred at 500 rpm for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, while stirring at 2,000 rpm, 5 g of deionized water was added dropwise at a rate of 1 g/min, and the dropwise addition was stopped and further stirred for 2 hours. Thereafter, 103 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared water-soluble epoxy resin dispersion had a solid content of 58% by weight, a viscosity at 25°C of 150 cps, and an epoxy equivalent of 1,250 g/eq.

2) Example 2. Preparation of water-soluble epoxy resin dispersion

To 850 g of the first modified epoxy resin of Preparation Example 4-2, 100 g of the second modified epoxy resin prepared in Preparation Example 1-1, 2 g of an auxiliary emulsifier (F108 from Adeka), and 5 g of butyl cellosolve were added, and the temperature was raised to 85°C. Then, the mixture was stirred for 30 minutes to prepare a mixture. Thereafter, 0.08 g of a dispersant (L-64 from Adeka) was added to the mixture, and the mixture was stirred at 500 rpm for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, while stirring at 2,000 rpm, 5 g of deionized water was added dropwise at a rate of 1 g/min, and the dropwise addition was stopped and further stirred for 2 hours. Thereafter, 103 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared water-soluble epoxy resin dispersion had a solid content of 57% by weight, a viscosity of 110 cps at 25°C, and an epoxy equivalent of 950 g/eq.

3) Example 3. Preparation of water-soluble epoxy resin dispersion

To 850 g of the first modified epoxy resin of Preparation Example 4-3, 100 g of the second modified epoxy resin prepared in Preparation Example 1-1, 2 g of an auxiliary emulsifier (F108 from Adeka) and 5 g of butyl cellosolve were added, and the temperature was raised to 85°C. Then, the mixture was stirred for 30 minutes to prepare a mixture. Thereafter, 0.08 g of a dispersant (L-64 from Adeka) was added to the mixture, and the mixture was stirred at 500 rpm for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, while stirring at 2,000 rpm, 5 g of deionized water was added dropwise at a rate of 1 g/min, and the dropwise addition was stopped and further stirred for 2 hours. Thereafter, 103 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared water-soluble epoxy resin dispersion had a solid content of 58% by weight, a viscosity of 900 cps at 25°C, and an epoxy equivalent of 870 g/eq.

4) Example 4. Preparation of water-soluble epoxy resin dispersion

To 850 g of the first modified epoxy resin of Preparation Example 4-1, 100 g of the second modified epoxy resin prepared in Preparation Example 1-2, 2 g of an auxiliary emulsifier (F108 from Adeka), and 5 g of butylcellosolve were added, and the temperature was raised to 85°C. Then, the mixture was stirred for 30 minutes to prepare a mixture. Thereafter, 0.08 g of a dispersant (L-64 from Adeka) was added to the mixture, and the mixture was stirred at 500 rpm for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, while stirring at 2,000 rpm, 5 g of deionized water was added dropwise at a rate of 1 g/min, and the dropwise addition was stopped and further stirred for 2 hours. Thereafter, 103 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared water-soluble epoxy resin dispersion had a solid content of 58% by weight, a viscosity of 1200 cps at 25°C, and an epoxy equivalent of 1,600 g/eq.

5) Example 5. Preparation of water-soluble epoxy resin dispersion

To 850 g of the first modified epoxy resin of Preparation Example 4-1, 100 g of the second modified epoxy resin prepared in Preparation Example 1-3, 2 g of an auxiliary emulsifier (F108 from Adeka), and 5 g of butyl cellosolve were added, and the temperature was raised to 85°C. Then, the mixture was stirred for 30 minutes to prepare a mixture. Thereafter, 0.08 g of a dispersant (L-64 from Adeka) was added to the mixture, and the mixture was stirred at 500 rpm for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, while stirring at 2,000 rpm, 5 g of deionized water was added dropwise at a rate of 1 g/min, and the dropwise addition was stopped and further stirred for 2 hours. Thereafter, 103 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared water-soluble epoxy resin dispersion had a solid content of 58% by weight, a viscosity at 25°C of 15,000 cps, and an epoxy equivalent of 1,700 g/eq.

Comparative Example 1. Preparation of epoxy resin dispersion

Put 100g of Kukdo Chemical's YD-011 in a 4-neck round flask with bisphenol-A epoxy resin, install a nitrogen gas pipe, H-type separator, stirrer, thermometer, and heater, and then 10g of emulsifier (F108 from Adeka) and butylcellosolve. After 5 g was added, the temperature was raised to 85°C and stirred for 30 minutes. Thereafter, 0.08 g of a dispersing agent (L-64 from Adeka) and an antifoaming agent (BYK-024 from BYK) were each added, followed by additional stirring for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, 20 g of deionized water was added dropwise at 900 rpm at a rate of 1 g/min, and the dropwise addition was stopped, followed by additional stirring for 1 hour. Thereafter, 65 g of deionized water was added dropwise at a rate of 1 g/min, cooled to room temperature, and the dispersion was terminated to prepare a water-soluble epoxy resin dispersion.

The prepared epoxy resin dispersion had a solid content of 55 wt%, a viscosity at 25°C of 120 cps, and an epoxy equivalent of 950 g/eq.

Comparative Example 2.

As a commercial product of the epoxy resin dispersion, EP387W of Allnex was used (solid content: 53% by weight, epoxy equivalent: 1,000 g/eq, viscosity at 25°C: 690 cps).

Comparative Example 3.

Air product's AR55 was used as a commercial product of the epoxy resin dispersion (solid content: 55% by weight, epoxy equivalent: 1040 g/eq, viscosity at 25°C: 220 cps).

Comparative Example 4. Example without using an emulsifier

Put 100g of Kukdo Chemical's YD-011 in a 4-neck round flask with bisphenol-A epoxy resin, install a nitrogen gas pipe, H-type separator, stirrer, thermometer, and heater, and then add 5g of butylcellosolve and heat to 85℃. And stirred for 30 minutes. Thereafter, 0.08 g of a dispersing agent (L-64 from Adeka) and an antifoaming agent (BYK-024 from BYK) were each added, followed by additional stirring for 30 minutes. Thereafter, the stirrer was changed to a high-speed stirrer, 20 g of deionized water was added dropwise at 900 rpm at a rate of 1 g/min, and the dropwise addition was stopped, followed by additional stirring for 1 hour. Thereafter, 65 g of deionized water was added dropwise at a rate of 1 g/min, and then cooled to room temperature to terminate the dispersion to prepare a water-soluble epoxy resin dispersion. This was impossible to measure.

Test Example: Evaluation of the properties of the manufactured coating film

A mixture was prepared by mixing the epoxy resin dispersions of Examples 1 to 5 and Comparative Examples 1 to 4 and an amine curing agent (Anquamine 401 from Air Products) in an equivalent ratio of 1:0.8. Thereafter, the mixture was coated to a thickness of 50 μm using an airless spray on a 1.6 mm-thick steel plate, followed by baking and curing at 80°C for 12 hours. The adhesion, rust prevention, and impact resistance were evaluated in the following manner with respect to the specimens for which bake hardening was completed, and the results are shown in Table 1.

(1) Workability (Sagging)

Immediately after coating the specimen with an airless spray method, a scratch was applied to the coating film using a Wet Film Thickness Gauge (WFT), and the length of the coating film flow was measured.

Specifically, the coating distance was 40cm, the spray gun pressure during coating was 3.5 bar, the temperature during coating was 25°C, and the relative humidity was 53%. Scratch length of the coating film was 80㎛, 175㎛, 225㎛, each length was indicated as good if the film did not flow down, and Sagging if flowed.

(2) Anti-corrosive property-1: Creep (IICL cyclic corrosion test Rust creep)

Cut a 1mm cut with a knife on the specimen, leave it for 3 days under UV-A of 340 nm, spray with 5% saline and leave for 4 days for a total of 8 times, and then the distance of rust penetration from the sheath (mm) Was measured to evaluate the rust prevention properties.

(3) Anti-rust-2: Whether bubbles are generated

After spraying 5% saline on the specimen and leaving it for 1,000 hours, the appearance of the specimen was observed, and the occurrence of bubbles was observed with the naked eye.

(4) adhesion

After allowing the specimen to stand at room temperature for 1,000 hours, draw 100 squares horizontally and vertically with a knife on the surface of the specimen (1mm horizontally × 1mm vertically), remove the squares with a tape, and measure the number of remaining squares. Evaluated.

At this time, if 100 squares are 100% fully attached, it is excellent (3B), if the remaining squares are 70% or more and less than 100%, good (2B), 50% or more and less than 70%, normal (1B), and if less than 50%, poor ( It evaluated as 0B).

(5) Impact resistance

After dropping a weight of 60 lbs, 5 lbs, or 8 lbs at a height of 39 inches on the front or rear surface of the specimen (the surface to which the epoxy resin dispersion and amine curing agent mixture was applied), the impact resistance was evaluated by observing the surface of the specimen.

Specifically, the test was evaluated as pass when no crack occurred on the surface of the specimen, and failed (×) when crack occurred.

division Example 1 Example 2 Example 3 Example 4 Example 5 Workability
(sagging) 80㎛ Good Good Good Good Good 175㎛ Good Good Good Good Good 225 μm Good Good Good Good sagging Anti-rust -1 (creep)(mm) 2.28 2.3 2.29 2.28 2.4 Anti-rust-2 (whether bubbles occur) Not occurring Not occurring Not occurring Not occurring Not occurring Adherence 3B 3B 3B 3B 2B Impact resistance Front 60 lbs pass pass pass pass pass 5 lbs rear pass pass pass pass pass Rear 8 lbs pass pass pass pass pass

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Workability
(sagging) 80㎛ Good Good Good Not measurable 175㎛ Good Good sagging Not measurable 225 μm sagging sagging sagging Not measurable Anti-rust -1 (creep)(mm) 2.5 2.5 2.4 Not measurable Anti-rust-2 (whether bubbles occur) Occur Occur Occur Not measurable Adherence 3B 3B 3B Not measurable Impact resistance Front 60 lbs fail fail pass Not measurable 5 lbs rear pass pass pass Not measurable Rear 8 lbs fail fail fail Not measurable

As shown in Table 1, it was found that the coating films prepared from the water-soluble epoxy resin dispersions of Examples 1 to 5 were excellent in workability, rust prevention, adhesion, and impact resistance.

On the other hand, as shown in Table 2, the coating film prepared from the epoxy resin dispersion of Comparative Example 1 containing only a general dispersant, not the second modified epoxy resin, containing an epoxy resin that does not contain a repeating unit derived from an anhydride resin Bubbles occurred in the air and the impact resistance was insufficient. In addition, the coating films of Comparative Examples 2 and 3 using commercially available products as an epoxy resin dispersion liquid also generated bubbles on the surface and had insufficient impact resistance. Further, Comparative Example 4 in which an emulsifier was not used was not water-dispersed and thus a coating film was not prepared.

Claims (7)

100 parts by weight of a first modified epoxy resin including a unit derived from a first epoxy resin and a unit derived from an anhydride resin; And
Including; 5 to 15 parts by weight of a second modified epoxy resin comprising a unit derived from a second epoxy resin and a unit derived from a polyhydric alcohol,
The epoxy equivalent of the first epoxy resin is 200 to 450 g/eq,
The anhydride resin is prepared by opening a ring structure of a cyclic anhydride with an alcohol, and the weight average molecular weight of the alcohol is 600 to 1,000 g/mol, a water-soluble epoxy resin dispersion. delete delete The method according to claim 1,
The first modified epoxy resin has an epoxy equivalent of 200 to 850 g / eq, a water-soluble epoxy resin dispersion. The method according to claim 1,
The second epoxy resin has an epoxy equivalent of 50 to 500 g/eq, a water-soluble epoxy resin dispersion. Preparing a first modified epoxy resin by reacting a first epoxy resin and an anhydride resin;
Reacting a second epoxy resin and a polyhydric alcohol to prepare a second modified epoxy resin; And
Including; dispersing 100 parts by weight of the first modified epoxy resin and 5 to 15 parts by weight of the second modified epoxy resin
The epoxy equivalent of the first epoxy resin is 200 to 450 g/eq,
The anhydride resin is prepared by opening a ring structure of a cyclic anhydride with an alcohol, and the weight average molecular weight of the alcohol is 600 to 1,000 g/mol, a method for preparing a water-soluble epoxy resin dispersion. The method of claim 6,
The step of preparing the second modified epoxy resin may include preparing an intermediate reactant by reacting a polyhydric alcohol and an anhydride; And reacting the intermediate reactant with the second epoxy resin.