KR102293684B1 - Water-soluble epoxy resin, preparing method thereof and water-soluble primer composition the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a water-soluble epoxy resin, including the steps of: manufacturing a first epoxy resin by reacting a polyalkylene polyol and a first bisphenol epoxy resin; manufacturing a second epoxy resin by reacting the first epoxy resin, bisphenol A, and a second bisphenol epoxy resin; and manufacturing a modified epoxy resin by reacting the second epoxy resin and an acid anhydride resin.

Description

Water-soluble epoxy resin, manufacturing method thereof, and aqueous primer composition comprising the same

The present invention provides a water-soluble epoxy resin capable of self-emulsification and excellent particle stability, a manufacturing method thereof, and a water-based primer having excellent paint storage properties and excellent sagging, rust prevention, adhesion and impact resistance due to low precipitation of zinc powder including the same to the composition.

Epoxy resins easily react with amines or acids to have a strong hardening structure. In particular, bisphenol-A epoxy resins are being applied in various industries due to their excellent chemical resistance, heat resistance, hardness, and flexibility due to their structure. In particular, in the paint field, an epoxy resin is used as a main component of a heavy-duty anticorrosive paint, a plant paint, etc., and it is used together with an amine or amide curing agent to show very good performance as a paint.

However, due to recent continuous environmental regulations, oil-soluble resins in the field where existing oil-soluble resins were used are rapidly being converted to water-soluble resins, and research on methods that can also water-soluble epoxy resins are actively conducted according to this change. is becoming For example, conventionally, water-soluble using various methods, such as an epoxy resin dispersed using an emulsifier, and a resin dispersed in water by substituting a part of the resin with a water-soluble functional group, are in progress.

Specifically, Japanese Patent No. 5587537 (Patent Document 1) discloses (I) a main agent including an epoxy resin emulsion and pigment powder, and (II) a two-component type in which the amine curing agent is mixed and coated immediately before use. A water-based paint is disclosed. However, the two-component water-based paint of Patent Document 1 uses a phosphoric acid-based rust-preventive pigment, which has a limitation in that it has inferior rust-preventive properties compared to the zinc-based rust-preventive pigment type.

In addition, in the current container paints, etc., water-based paints equivalent to the physical properties of existing oil-soluble paints are applied in accordance with continuous environmental regulations, but the physical properties and workability of the manufactured coating films were slightly inferior compared to oil-soluble paints.

Therefore, there is a need for research and development on a water-based primer composition that is eco-friendly because it is water-based, has excellent paint storability due to low zinc powder precipitation, and that the coating film prepared therefrom has excellent sagging properties, rust prevention properties, adhesion and impact resistance.

Japanese Patent Registration No. 5587537 (published on: 2009.7.9.)

The present invention provides a water-soluble epoxy resin capable of self-emulsification and excellent particle stability upon water-solution, a method for preparing the same, and a low precipitation of zinc powder including the same, so that the paint storage property is excellent, and the sagging property, rust prevention property, adhesion and impact resistance are excellent. An excellent aqueous primer composition is provided.

In order to achieve the above object, the present invention comprises the steps of preparing a first epoxy resin by reacting a polyalkylene polyol and a first bisphenol epoxy resin;

preparing a second epoxy resin by reacting the first epoxy resin, bisphenol A, and a second bisphenol epoxy resin; and

It provides a method for producing a water-soluble epoxy resin, including; preparing a modified epoxy resin by reacting the second epoxy resin and an acid anhydride resin.

In addition, the present invention provides a water-soluble epoxy resin prepared by the above manufacturing method and having an epoxy equivalent of 300 to 600 g/eq.

In addition, the present invention provides an aqueous primer composition comprising the water-soluble epoxy resin and zinc powder.

The water-soluble epoxy resin according to the present invention is capable of self-emulsification by including the first epoxy resin derived from polyalkylene polyol having a water-soluble function, and has excellent particle stability upon water-soluble. In addition, the water-soluble epoxy resin includes a unit derived from an acid anhydride resin having flexibility, and the coating film prepared therefrom has excellent impact resistance. In addition, since the water-soluble epoxy resin is capable of dispersing zinc powder, it can be applied as a main resin of an aqueous primer composition containing zinc powder.

In addition, the aqueous primer composition according to the present invention is eco-friendly because it is water-based, and the precipitation of zinc powder including the water-soluble epoxy resin is small, so the storage property of the paint is excellent. In addition, the aqueous primer composition can be applied to various fields where conventional oil-soluble resins, such as paints for containers, have been applied because the coating film prepared therefrom has excellent sagging properties, rust prevention properties, adhesion properties and impact resistance.

Hereinafter, the present invention will be described in detail.

As used herein, "weight average molecular weight" is measured by a conventional method known in the art, for example, it can be measured by a GPC (gel permeation chromatograph) method.

Method for producing water-soluble epoxy resin

The method for producing a water-soluble epoxy resin according to the present invention comprises the steps of preparing a first epoxy resin; preparing a second epoxy resin; and preparing a modified epoxy resin by reacting the second epoxy resin and an acid anhydride resin.

Preparation of the first epoxy resin

In this step, the polyalkylene polyol and the first bisphenol epoxy resin are reacted to prepare a first epoxy resin.

The polyalkylene polyol serves to enable self-emulsification by imparting water solubility to the first epoxy resin. In this case, the polyalkylene polyol may have a weight average molecular weight (Mw) of 1,500 to 8,000 g/mol, or 2,000 to 6,000 g/mol. In addition, the polyalkylene polyol may be used as a mixture of two or more types having different molecular weights as needed. When the weight average molecular weight of the polyalkylene polyol exceeds the above range, water solubility performance is good, but crystallization may occur during low temperature storage due to crystallinity due to high molecular weight. In addition, when the weight average molecular weight of the polyalkylene polyol is less than the above range, the problem of crystallization can be prevented, but problems in appearance and rust prevention may be deteriorated due to poor water solubility performance.

In addition, the alkylene of the polyalkylene polyol may have 2 to 5, 2 to 3 carbon atoms, and may have 2 to 4, or 2 or 3 hydroxyl groups (-OH). Specifically, the polyalkylene polyol may include at least one selected from the group consisting of polyethylene glycol, polypropylene glycol and polybutylene glycol.

Although the type of the first bisphenol epoxy resin is not particularly limited, for example, it may be at least one selected from the group consisting of a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, and a bisphenol S-type epoxy resin. Specifically, the first bisphenol epoxy resin may be a bisphenol A-type epoxy resin, and commercially available products include YD-128 (epoxy equivalent: 190 g/eq), YD-011 (epoxy equivalent: 475 g/eq) of Kukdo Chemical. etc. may be used.

In addition, the first bisphenol epoxy resin may have an epoxy equivalent weight (EEW) of 100 to 600 g/eq, or 120 to 500 g/eq. When the epoxy equivalent of the first bisphenol epoxy resin is within the above range, there is an effect of excellent workability and reactivity.

The polyalkylene polyol and the first bisphenol epoxy resin may be reacted in an equivalent ratio of 1: 1.5 to 4.5, or 1: 2 to 4 in an equivalent ratio. When the equivalence ratio is less than the above range, the reaction time becomes longer and productivity is lowered and side reactions may occur.

The first epoxy resin may be prepared by reacting for 4 to 8 hours after raising the temperature to 120 to 160 ℃. Specifically, the first epoxy resin may be prepared by reacting for 5 to 7 hours after raising the temperature to 130 to 150 ℃. In this case, the first epoxy resin may be prepared using a catalyst, and the catalyst is not particularly limited as long as it is a conventional catalyst capable of promoting the reaction of an epoxy group and a hydroxyl group. For example, boron trifluoride (Boron trifluoride) ) may be a derivative.

The first epoxy resin may have an epoxy equivalent weight (EEW) of 800 to 1,500 g/eq, or 900 to 1,200 g/eq. When the epoxy equivalent of the first epoxy resin is within the above range, there is an effect of excellent adhesion and coating film strength.

Preparing a second epoxy resin

In this step, the second epoxy resin is prepared by reacting the first epoxy resin, bisphenol A, and the second bisphenol epoxy resin. In addition, in this step, the molecular weight may be increased by reacting the first epoxy resin with the bisphenol A and the second bisphenol epoxy resin.

Although the type of the second bisphenol epoxy resin is not particularly limited, for example, it may be at least one selected from the group consisting of a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, and a bisphenol S-type epoxy resin. Specifically, the second bisphenol epoxy resin may be a bisphenol A type epoxy resin, and commercially available products include YD-128 (epoxy equivalent: 190 g/eq) of Kukdo Chemical, YD-011 (epoxy equivalent: 475 g/eq). etc. may be used.

In addition, the second bisphenol epoxy resin may have an epoxy equivalent weight (EEW) of 100 to 600 g/eq, or 120 to 500 g/eq. When the epoxy equivalent of the second bisphenol epoxy resin is within the above range, there is an effect of excellent workability and reactivity.

In this step, the mixing ratio of the first epoxy resin, bisphenol A and the second bisphenol epoxy resin can be appropriately adjusted according to the target epoxy equivalent weight, for example, the first epoxy resin, bisphenol A and the second bisphenol epoxy resin are 1: 5 The reaction may be carried out in an equivalent ratio of 15: 20 to 40, or 1: 8 to 12: 25 to 35 in an equivalent ratio. When the equivalent ratio of the first epoxy resin, bisphenol A and the second bisphenol epoxy resin is within the above range, there is an effect excellent in coating film strength and workability.

The second epoxy resin may be prepared by raising the temperature to 120 to 160 ℃ and reacting for 2 to 6 hours. Specifically, the second epoxy resin may be prepared by reacting for 3 to 5 hours after raising the temperature to 130 to 150 ℃. At this time, the second epoxy resin may use a catalyst during production, and the catalyst is not particularly limited as long as it is a conventional catalyst applicable to the production of an epoxy resin, for example, the catalyst is ethyltriphenylphosphonium It may be bromide (Ethyltriphenylphosphonium bromide).

The second epoxy resin may have an epoxy equivalent weight (EEW) of 200 to 500 g/eq, or 300 to 400 g/eq. When the epoxy equivalent of the second epoxy resin is within the above range, there is an effect excellent in rust prevention properties and coating film strength.

Step of preparing a modified epoxy resin

In this step, the modified epoxy resin is prepared by reacting the second epoxy resin and the acid anhydride resin.

The acid anhydride resin serves as a branch to the modified epoxy resin to provide flexibility to the modified epoxy resin. In this case, the acid anhydride resin may be prepared by reacting alcohol and cyclic anhydride. In addition, the acid anhydride resin may be prepared by reacting a cyclic anhydride with an alcohol to open a ring structure of the cyclic anhydride.

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

The alcohol may be a polyol containing two or more hydroxyl groups (-OH), for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, and methyl polypropylene glycol. In this case, the alcohol may have a weight average molecular weight (Mw) of 400 to 10,000 g/mol, 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 the above range, the prepared resin and coating film are too soft (Soft), and the impact resistance is inferior. There may be problems with degradation.

For example, the acid anhydride resin may be prepared by mixing alcohol and cyclic anhydride in a molar ratio of 1: 0.8 to 3, raising the temperature to 120 to 150 °C, and reacting for 1 to 7 hours. Specifically, the acid anhydride resin may be prepared by mixing 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.

The acid anhydride resin may have a hydroxyl value (OHV) of 10 to 100 mgKOH/g, or 10 to 60 mgKOH/g. When the hydroxyl value of the acid anhydride resin is out of the above range, rust prevention properties may be deteriorated.

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

The acid anhydride resin may have a weight average molecular weight (Mw) of 200 to 2,000 g/mol, or 500 to 800 g/mol. When the weight average molecular weight of the acid anhydride resin is out of the above range, workability may be deteriorated and impact resistance may be inferior.

According to the target epoxy equivalent of the modified epoxy resin, the mixing ratio of the second epoxy resin and the acid anhydride resin can be appropriately adjusted. For example, the second epoxy resin and the acid anhydride resin may be reacted in a 100: 10 to 20 weight ratio, or 100: 10 to 14 weight ratio. When the mixing ratio is less than the above range, the flexibility of the modified epoxy resin is lowered and the impact resistance is lowered. .

In addition, the modified epoxy resin may be prepared by reacting for 1 to 5 hours after raising the temperature to 110 to 150 ℃. Specifically, the modified epoxy resin may be prepared by raising the temperature to 120 to 140 ℃ and reacting for 2 to 4 hours.

At this time, the modified epoxy resin may use a catalyst during production, and the catalyst is not particularly limited as long as it is a conventional catalyst applicable to the production of an epoxy resin. For example, the catalyst is triphenylphosphine. can be

water-soluble epoxy resin

The water-soluble epoxy resin according to the present invention is prepared by the manufacturing method as described above, and has an epoxy equivalent weight (EEW) of 300 to 600 g/eq. For example, the water-soluble epoxy resin may have an epoxy equivalent of 400 to 500 g/eq. When the epoxy equivalent of the water-soluble epoxy resin is less than the above range, the dry properties of the coating film are lowered and the rust prevention property is inferior.

The water-soluble epoxy resin may further include a hydrophilic solvent, a viscosity at 25° C. of 500 to 2,000 cps, and a solid content of 60 to 90% by weight or 70 to 80% by weight.

In this case, the hydrophilic solvent serves to adjust the viscosity of the water-soluble epoxy resin. The hydrophilic solvent is not particularly limited as long as it is a common solvent capable of diluting the epoxy resin, but it is preferable that the hydrophilic solvent has good compatibility with water. For example, the hydrophilic solvent may include butyl cellusolve, 1-methoxy-2-propanol, isopropyl alcohol, and the like.

The water-soluble epoxy resin as described above is capable of self-emulsification by including the first epoxy resin derived from polyalkylene polyol having a water-soluble function, and has excellent stability of particles during water-solution. In addition, the water-soluble epoxy resin includes a unit derived from an acid anhydride resin having flexibility, and the coating film prepared therefrom has excellent impact resistance. In addition, since the water-soluble epoxy resin is capable of dispersing zinc powder, it can be applied as a main resin of an aqueous primer composition containing zinc powder.

Aqueous Primer Composition

In addition, the aqueous primer composition according to the present invention includes the water-soluble epoxy resin and zinc powder.

The aqueous primer composition may include a first composition comprising the water-soluble epoxy resin and zinc powder; and a second composition comprising a water-soluble amide curing agent and water. That is, the aqueous primer composition may be a two-component coating composition including the first composition and the second composition.

The zinc powder and the water-soluble amide curing agent are not particularly limited as long as they are generally applicable to water-based paints.

For example, the first composition may include 100 parts by weight of a water-soluble epoxy resin and 400 to 800 parts by weight, or 500 to 700 parts by weight of zinc powder. When the mixing ratio of the water-soluble epoxy resin and the zinc powder is within the above range, the zinc powder is not precipitated, so that the storage property is excellent.

In addition, the second composition may include 10 parts by weight of a water-soluble amide curing agent and 30 to 130 parts by weight, or 50 to 100 parts by weight of water.

In addition, the aqueous primer composition may include a water-soluble epoxy resin and an amide curing agent in an equivalent ratio of 1: 0.4 to 0.8, or 1: 0.5 to 0.7 in an equivalent ratio.

The aqueous primer composition as described above is eco-friendly because it is water-based, and the precipitation of zinc powder including the water-soluble epoxy resin as described above is small, so that the paint has excellent storability. In addition, the aqueous primer composition can be applied to various fields where conventional oil-soluble resins, such as paints for containers, have been applied because the coating film prepared therefrom has excellent sagging properties, rust prevention properties, adhesion properties and impact resistance.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Preparation Example 1. Preparation of 1-1 epoxy resin to 1-6 epoxy resin

In the same content as in Table 1, polyethylene glycol, the first bisphenol epoxy resin and catalyst (Evonik, Anchor1115) were put in a four-necked round flask, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer and a heater were installed. Thereafter, the temperature was raised to 150° C. and reacted for 6 hours, and cooled to room temperature to obtain a light brown first epoxy resin.

Ingredients (parts by mass) first epoxy resin 1-1 1-2 1-3 1-4 1-5 1-6 Polyethylene glycol with Mw 2,000 g/mol 250 - - 150 250 250 Polyethylene glycol with Mw 4,000 g/mol 500 - - 300 500 500 Polyethylene glycol with Mw 1,000 g/mol - 500 - - - - Polyethylene glycol with Mw 6,000 g/mol - - 900 - - - first bisphenol epoxy resin YD-128, Kukdo Chemical 280 560 224 - 300 252 YD-011, Kukdo Chemical - - - 564 - - catalyst 1.5 One 1.8 One 1.5 - Epoxy equivalent weight of the prepared epoxy resin (g/eq) 1,032 530 1,200 1,130 955 1,180

Preparation Example 2. Preparation of Nos. 2-1 Epoxy Resins to Nos. 2-7 Epoxy Resins

In the same content as in Table 2, put the first epoxy resin, bisphenol-A, the second bisphenol epoxy resin (YD-128, Kukdo Chemical) and the catalyst (ethyltriphenylphosphonium bromide, Ethyltriphenylphosphonium bromide) in a four-necked round flask , nitrogen gas pipe, H-type separation pipe, stirrer, thermometer and heater were installed. Thereafter, the temperature was raised to 145° C. and reacted for 3 hours, and cooled to room temperature to obtain a light brown second epoxy resin.

Ingredients (parts by mass) 2nd epoxy resin 2-1 2-2 2-3 2-4 2-5 2-6 2-7 Article 1-1 Epoxy Resin 202 - 202 - - - - Part 1-2 Epoxy Resin - 312 - - - - - Article 1-3 Epoxy Resin - - - 168 - - - Article 1-4 Epoxy Resin - - - - 304 - - Article 1-5 Epoxy Resin - - - - - 189 - Article 1-6 Epoxy Resin - - - - - - 180 Bisphenol A 235 200 325 225 180 216 216 Second bisphenol epoxy resin 1,176 920 1,176 1,125 990 1,080 1,080 catalyst 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Epoxy equivalent weight of the prepared epoxy resin (g/eq) 365 362 470 364 370 364 366

Preparation Example 3. Preparation of modified epoxy resin

3-1: Preparation of acid anhydride resin

800 g of polypropylene glycol and 304 g of tetrahydrophthalic anhydride having a weight average molecular weight of 800 g/mol were placed in a four-necked round flask, and a nitrogen gas pipe, an H-type separator, a stirrer, a thermometer and a heater were installed. Then, after raising the temperature to 140 ℃, reacted for 5 hours, cooled to room temperature to obtain an acid anhydride resin.

The prepared acid anhydride resin 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 is Gardner viscosity Z3 appear.

3-2: Preparation of modified epoxy resins-1 to 8

The second epoxy resin, acid anhydride resin, and triphenylphosphine catalyst were put into a four-necked round flask at the same content as in Table 3, and the temperature was raised to 130° C. and maintained for 3 hours. Thereafter, the mixture was cooled to 100° C. and diluted with 1-methoxy-2-propanol as a hydrophilic solvent to obtain a modified epoxy resin, and the physical properties of the modified epoxy resin are shown in Table 4.

Components (parts by mass) Modified Epoxy Resin One 2 3 4 5 6 7 8 Article 2-1 Epoxy Resin 1,614 - 1,614 - - - - - 2-2 Epoxy Resin - 1,430 - - - - - - Part 2-3 Epoxy Resin - - - 1,706 - - - - 2-4 Epoxy Resin - - - - 1,518 - - - Article 2-5 Epoxy Resin - - - - - 1,474 - - 2-6 Epoxy Resin - - - - - - 1,485 - Article 2-7 Epoxy Resin - - - - - - - 1,485 acid anhydride resin 217 217 155 - 180 165 180 180 catalyst 0.2 0.2 0.1 0.2 0.2 0.2 0.2 0.2 1-methoxy-2-propanol 627 627 627 630 628 606 616 616

Modified Epoxy Resin One 2 3 4 5 6 7 8 solid content 73 73 73 73 73 73 73 73 Epoxy equivalent
(based on solids, g/eq) 470 483 441 462 467 466 466 470 Viscosity (@25℃, cps) 1,320 1,000 1,150 3,200 1,920 1,430 1,200 1,250

Preparation Example 4. Preparation of Epoxy Resin-a Not Solubilized with Polyalkylene Polyol

In a four-necked round flask, put 270 g of bisphenol-A, 1,231 g of the second bisphenol epoxy resin (Kukdo Chemical, YD-128) and 0.2 g of ethyltriphenylphosphonium bromide, a nitrogen gas pipe, an H-type separation pipe, A stirrer, thermometer and heater were installed. Then, the temperature was raised to 145° C. and reacted for 3 hours, cooled to room temperature to obtain a light brown epoxy resin-a1 having an epoxy equivalent of 365 g/eq.

1,501 g of the prepared epoxy resin-a1, 217 g of the acid anhydride resin prepared in Preparation Example 3-1, and 0.2 g of a triphenylphosphine catalyst were mixed, and the temperature was raised to 130° C. and maintained for 3 hours. Thereafter, the mixture was cooled to 100° C. and diluted with 627 g of 1-methoxy-2-propanol as a hydrophilic solvent to obtain an epoxy resin-a.

The prepared epoxy resin-a had a solid content of 73% by weight, an epoxy equivalent of 470 g/eq on a solid basis, and a viscosity of 6,150 cps at 25°C.

Preparation Example 5. Preparation of epoxy resin-b

5-1: epoxy resin-b1

In a four-necked round flask, 250 g of polyethylene glycol with a weight average molecular weight of 2,000 g/mol, 500 g of polyethylene glycol with a weight average molecular weight of 4,000 g/mol, 560 g of the first bisphenol epoxy resin (Kukdo Chemical, YD-128) and a catalyst (Evonik, Anchor1115) ) was added, and a nitrogen gas pipe, an H-type separation pipe, a stirrer, a thermometer and a heater were installed. Thereafter, the temperature was raised to 150° C. and reacted for 6 hours, and cooled to room temperature to obtain a light brown epoxy resin-b1 having an epoxy equivalent of 520 g/eq.

5-2: epoxy resin-b2

258 g of the prepared epoxy resin-b1, 235 g of bisphenol-A, 1,231 g of the second bisphenol epoxy resin (Kukdo Chemical, YD-128) and 0.2 g of ethyltriphenylphosphonium bromide were put in a 4-neck round flask, and a nitrogen gas pipe, H A mold separation tube, stirrer, thermometer and heater were installed. Thereafter, the temperature was raised to 145° C. and reacted for 3 hours, and then cooled to room temperature to obtain a light brown epoxy resin-b2 having an epoxy equivalent of 355 g/eq.

5-3: epoxy resin-b

Into a four-necked round flask, 1,563 g of epoxy resin-b2, 217 g of the acid anhydride resin prepared in Preparation Example 3-1, and 0.2 g of a triphenylphosphine catalyst were placed, and the temperature was raised to 130° C. and maintained for 3 hours. Thereafter, the mixture was cooled to 100° C. and diluted with 650 g of 1-methoxy-2-propanol as a hydrophilic solvent to obtain an epoxy resin-b.

The prepared epoxy resin-b had a solid content of 73% by weight, an epoxy equivalent of 455 g/eq on a solid basis, and a viscosity of 950 cps at 25°C.

When the paint was prepared with the epoxy resin-b, the water-soluble functional group was relatively insufficient, so the compatibility of the prepared paint was insufficient, and agglomeration occurred during operation.

Preparation Example 6. Preparation of epoxy resin-c

6-1: epoxy resin-c1

In a four-necked round flask, 202 g of the 1-1 epoxy resin of Preparation Example 1, 315 g of bisphenol-A, 916 g of the second bisphenol epoxy resin (Kukdo Chemical, YD-128) and 0.2 g of ethyltriphenylphosphonium bromide were put, and nitrogen A gas pipe, an H-type separation pipe, a stirrer, a thermometer and a heater were installed. Thereafter, the temperature was raised to 145° C. and reacted for 3 hours, and cooled to room temperature to obtain a pale brown epoxy resin-c1 having an epoxy equivalent of 615 g/eq.

6-2: epoxy resin-c

Into a four-necked round flask, 1,580 g of epoxy resin-c1, 217 g of the acid anhydride resin prepared in Preparation Example 3-1, and 0.2 g of a triphenylphosphine catalyst were placed, and the temperature was raised to 130° C. and maintained for 3 hours. Thereafter, the mixture was cooled to 100° C. and diluted with 600 g of 1-methoxy-2-propanol as a hydrophilic solvent to obtain an epoxy resin-c.

The prepared epoxy resin-c had a solid content of 72% by weight, an epoxy equivalent of 920 g/eq based on the solid content, and the viscosity at 25° C. was impossible to measure due to high viscosity and crystallization.

Examples 1 to 7 and Comparative Examples 1 to 5. Preparation of aqueous primer composition

An aqueous primer composition was prepared by mixing the components in the same content as in Tables 5 and 6.

Ingredients (parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 first composition Modified Epoxy Resin-1 100 - - - - - - Modified Epoxy Resin-2 - 100 - - - - - Modified Epoxy Resin-3 - - 100 - - - - Modified Epoxy Resin-5 - - - 100 - - - Modified Epoxy Resin-6 - - - - 100 - - Modified Epoxy Resin-7 - - - - - 100 - Modified Epoxy Resin-8 - - - - - - 100 zinc powder 600 600 600 600 600 600 600 second composition Water-soluble amide curing agent 10 10 10 10 10 10 10 water 80 80 80 80 80 80 80 Mixing weight ratio of the first composition and the second composition 6:1 6:1 6:1 6:1 6:1 6:1 6:1

Ingredients (parts by weight) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 first composition Water-soluble amide curing agent 10 - - - - Modified Epoxy Resin-4 - 100 - - - Epoxy resin-a - - 100 - - Epoxy resin-b - - - 100 - epoxy resin-c - - - - 100 zinc powder 600 600 600 600 600 second composition Water-soluble amide curing agent - 10 10 10 10 Epoxy Emulsion 200 - - - - water - 80 80 80 80 Mixing weight ratio of the first composition and the second composition 4:1 6:1 6:1 6:1 6:1

Hereinafter, the manufacturers and product names, or component names, etc. of each component used in Comparative Examples and Examples are shown in Table 7.

ingredient note zinc powder Manufacturer: Hanil, Product name: Zinc dust Water-soluble amide curing agent Solid content 80% by weight and active hydrogen equivalent: 150 (g/eq) Epoxy Emulsion Manufacturer: Hexion, product name: EP6538

Experimental Example 1. Characteristic evaluation

The storage properties of the aqueous primer compositions were evaluated in Examples and Comparative Examples, and the results are shown in Tables 8 and 9.

In addition, the prepared aqueous primer composition was coated with an airless spray to a thickness of 30 μm on an iron plate having a thickness of 1.6 mm, then left at room temperature for 10 minutes and baked and cured at 60° C. for 30 minutes. In the coating method, the coating distance was 40 cm, the spray gun pressure was 3.5 bar during coating, the coating temperature was 25° C., and the relative humidity was 55%. The physical properties of the specimens on which bake hardening was completed were evaluated in the following manner, and the results are shown in Tables 8 and 9.

(1) storability

After the primer composition was stopped at 60° C. for 7 days, storage properties were confirmed through precipitation of zinc powder.

(2) sagging

Immediately after coating the specimen by the airless spray method, a wet film thickness gauge (WFT) was used to scratch the coating film, and then the length of flow was measured.

Specifically, the lengths of the scratches were 125 μm, 175 μm, and 225 μm, and if the coating film did not flow down for each length, it was good, and if it flowed, it was expressed as sagging.

(3) Anti-rust-1: Creep (IICL cyclic corrosion test Rust creep)

A 1 mm sheath was made on the specimen with a blade, left for 3 days under UV-A of 340 nm, sprayed with 5% by weight of saline and left for 4 days, a total of 8 times, after processing a total of 8 times, the distance from which rust penetrated from the sheath ( mm) to evaluate the rust prevention properties.

(4) Anti-rust-2: Whether or not air bubbles are generated

After spraying 5% by weight of salt water on the specimen and leaving it to stand for 1,000 hours, the appearance of the specimen was observed to visually inspect whether bubbles were generated.

(5) Adhesiveness

After leaving the specimen at room temperature for 1,000 hours, draw 100 squares horizontally and vertically with a knife blade on the surface of the specimen, remove the squares using tape, and measure the number of remaining squares to evaluate the adhesion. did.

At this time, if 100 squares are 100% completely attached, excellent (3B), if the remaining squares are 70% or more and less than 100%, good (2B), if 50% or more and less than 70%, normal (1B), if less than 50%, bad ( 0B).

(6) Impact resistance

After dropping a weight of 5 lbs or 8 lbs from a height of 39 inches to the back of the specimen, the surface of the specimen was observed to evaluate the impact resistance.

Specifically, when cracks did not occur on the surface of the specimen, it was evaluated as pass, and when cracks occurred, it was evaluated as fail (X).

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Zhejiang Good Good Good Good Good Good Good sagging 125㎛ Good Good Good Good Good Good Good 175㎛ Good Good Good Good Good Good Good 225㎛ Good Good Good Good Good Good Good Anti-rust-1 Creep (mm) 2.2 3.0 2.4 2.1 2.5 2.4 2.5 Anti-rust-2 bubble generation non-occurring generation non-occurring non-occurring non-occurring non-occurring non-occurring adherence 3B 2B 3B 3B 3B 3B 3B impact resistance rear 5 lbs 4/4 4/4 4/4 4/4 4/4 4/4 4/4 rear 8 lbs 4/4 4/4 2/4 4/4 4/4 4/4 4/4

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Zhejiang sedimentation Good sedimentation sedimentation Good sagging 125㎛ Good Good not measurable not measurable Good 175㎛ Good Good not measurable not measurable Good 225㎛ Good Good not measurable not measurable Good Anti-rust-1 Creep (mm) 2.3 3.2 not measurable not measurable 3.3 Anti-rust-2 bubble generation non-occurring non-occurring not measurable not measurable generation adherence 3B 2B not measurable not measurable 1B impact resistance rear 5 lbs 4/4 2/4 not measurable not measurable 3/4 rear 8 lbs 3/4 0/4 not measurable not measurable 1/4

As shown in Table 8, it was found that the compositions of Examples 1 to 7 had excellent storage properties and excellent physical properties of the coating films prepared therefrom.

On the other hand, as shown in Table 9, the compositions of Comparative Examples 1 to 5 were found to have poor paint storage properties, sagging properties, rust prevention properties, adhesion properties and impact resistance compared to Examples 1 to 7.

Specifically, the aqueous primer composition prepared by mixing the first composition prepared with the water-soluble amide curing agent and zinc powder of Comparative Example 1, and the second composition to which the epoxy emulsion was applied, had poor paint storage properties compared to Examples 1 to 7. .

In addition, the aqueous primer composition prepared by applying the modified epoxy resin-4 to which the acid anhydride resin of Comparative Example 2 was not applied had poor rust prevention and impact resistance compared to Examples 1 to 7.

In addition, since the first composition prepared by applying the modified epoxy resin-a to which the polyalkylene polyol of Comparative Example 3 is not applied does not have a water-soluble functional group in the modified epoxy resin, when the second composition is added, the first composition and the first composition Due to the lack of compatibility between the two compositions, agglomeration occurred during the operation, and the painting could not proceed. In addition, in the composition of Comparative Example 3, precipitation of zinc powder occurred within 7 days.

In addition, the aqueous primer composition to which the modified epoxy resin-b prepared so that the equivalent ratio of the polyalkylene polyol of Comparative Example 4 and the first bisphenol epoxy resin exceeds 1: 1.5 to 4.5 is a functional group water-soluble in the modified epoxy resin-b Due to the lack of compatibility in the paint, agglomeration occurred during work, which made it impossible to proceed with the painting. Furthermore, when the composition of Comparative Example 4 was injected, the compatibility between the first composition and the second composition was insufficient, so that agglomeration occurred during the operation, so that painting could not proceed. In addition, in the composition of Comparative Example 4, precipitation of zinc powder occurred within 7 days.

In addition, the water-based primer paint containing the modified epoxy resin-c to which the second epoxy resin having an epoxy equivalent of Comparative Example 5 exceeds 100 to 600 g/eq has antirust properties, adhesion and impact resistance in Examples 1 to 7 was poor compared to

Claims (7)

preparing a first epoxy resin by reacting a polyalkylene polyol and a first bisphenol epoxy resin in an equivalent ratio of 1:2 to 1:4;
preparing a second epoxy resin by reacting the first epoxy resin, bisphenol A, and a second bisphenol epoxy resin; and
Preparing a modified epoxy resin having an epoxy equivalent weight (EEW) of 400 to 500 g/eq by reacting the second epoxy resin and an acid anhydride resin; Containing, a method for producing a water-soluble epoxy resin. The method according to claim 1,
The polyalkylene polyol has a weight average molecular weight of 1,500 to 8,000 g/mol, a method for producing a water-soluble epoxy resin. The method according to claim 1,
The second bisphenol epoxy resin has an epoxy equivalent weight (EEW) of 100 to 600 g/eq, a method for producing a water-soluble epoxy resin. The method according to claim 1,
The second epoxy resin and the acid anhydride resin are 100: a method for producing a water-soluble epoxy resin by reacting in a weight ratio of 10 to 20. A water-soluble epoxy resin prepared by the method of any one of claims 1 to 4, and having an epoxy equivalent of 400 to 500 g/eq. 6. The method of claim 5,
The water-soluble epoxy resin further comprises a hydrophilic solvent, the viscosity at 25 ℃ is 500 to 2,000 cps, the solid content is 60 to 90% by weight, the water-soluble epoxy resin. An aqueous primer composition comprising the water-soluble epoxy resin of claim 5 and zinc powder.