阅读说明：本技术 一种水性环氧固化剂及其制备方法 (Water-based epoxy curing agent and preparation method thereof ) 是由 陈子方 张士鸣 徐达洋 袁浩凌 陈永东 于 2020-06-02 设计创作，主要内容包括：水性环氧固化剂,采用混合型乳化剂,乳化剂带亲水基团和亲油基团；此混合型乳化剂再和脂肪胺固化剂合成反应,再加水配成水性固化剂；反应性乳化剂采用丙烯酰胺基异丙基磺酸钠加聚丙烯酰胺脂肪醇聚氧乙烯醚混合物,重量比：30-70～70-30；脂肪胺固化剂中脂肪族多元胺包括乙二胺、己二胺、二乙烯三胺、三乙烯四胺、二乙氨基丙胺中的至少一种。此固化剂的新型性在于：可与纯双酚A环氧树脂或柔性环氧树脂反应,不需要用水性环氧树脂配合使用,这就避免了水性环氧中含有的1.5～5％的助溶剂,在生产应用中能达到真正的绿色)。(The water-based epoxy curing agent adopts a mixed emulsifier, and the emulsifier is provided with a hydrophilic group and a lipophilic group; the mixed emulsifier is subjected to synthetic reaction with a fatty amine curing agent, and water is added to prepare a water-based curing agent; the reactive emulsifier is a mixture of acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether, and the weight ratio is as follows: 30-70-30; the aliphatic polyamine in the aliphatic amine curing agent comprises at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine. The curing agent has the following novel properties: can react with pure bisphenol A epoxy resin or flexible epoxy resin, does not need to be matched with aqueous epoxy resin for use, thus avoiding 1.5-5 percent of cosolvent contained in the aqueous epoxy, and achieving real green in production and application).)

1. The water-based epoxy curing agent is characterized in that a mixed emulsifier is adopted, and the emulsifier is provided with a hydrophilic group and a lipophilic group; the mixed emulsifier is subjected to synthetic reaction with a fatty amine curing agent, and water is added to prepare a water-based curing agent; the reactive emulsifier is a mixture of acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether, and the weight ratio is as follows: 30-70-30; the aliphatic polyamine in the aliphatic amine curing agent comprises at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine.

2. The aqueous epoxy curing agent according to claim 1, wherein 1000PPM of a polymerization inhibitor is added.

3. The aqueous epoxy hardener as claimed in claim 1, wherein the reaction system used is: pure epoxy: and (3) forming a solvent-free water-based reaction system by using the solvent-free curing agent which is 1: 1-1.5.

4. The preparation method of the aqueous epoxy hardener as claimed in one of claims 1 to 3, wherein the mixed emulsifier is selected from sodium acrylamido isopropyl sulfonate and polyacrylamide fatty alcohol polyoxyethylene ether; stirring and mixing at 80 +/-15 ℃; the second step of the preparation of the curing agent comprises the following steps: mixing type emulsifier: aliphatic polyamine is synthesized at about 60 +/-15 ℃ in a weight ratio of 1: 1.5-2.5, and water is added to prepare an aqueous solution; the aliphatic polyamine is at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and diethylaminopropylamine.

Technical Field

The invention relates to a water-based epoxy curing agent, a preparation method and application thereof, and belongs to the technical field of epoxy resin.

Background

The solvent-free high polymer material is the development direction of the industry; the applicant has also obtained an authorised method for the synthesis and curing of CN2016111495774 solvent-free high Tg liquid phosphorous epoxy resin; the applicant is a mass-production producer of epoxy resins; due to excellent adhesive force, electrical insulation, thermal stability and mechanical property, the epoxy resin is widely applied in the industrial production fields of coatings, advanced composite materials, engineering plastics, electronic and electrical appliance materials and the like. The water-based epoxy curing agent is an important component of a water-based epoxy system, and the composition and the structure of the water-based epoxy curing agent play a decisive role in the physical and chemical properties of a coating film. The research on the epoxy curing agent is relatively active abroad, the variety of the curing agent is more, the confidentiality is strong, and the development of the novel epoxy curing agent is favorable for opening up new application of the epoxy resin. The aqueous epoxy curing agent is usually modified polyamine, such as amidoamine, polyamide adduct, epoxy-polyamine adduct, etc., wherein the epoxy-polyamine adduct is suitable for room temperature curing aqueous epoxy coating. The key to preparing the curing agent is to ensure that primary amine on polyamine is converted as completely as possible through ring-opening reaction of epoxy resin and polyamine, thereby reducing the reactivity of polyamine, prolonging the room-temperature shelf life of the polyamine and simultaneously improving the compatibility with epoxy resin components. Chinese patent CN109517141A discloses a cardanol modified waterborne epoxy curing agent and a preparation method thereof, which improve the thermal stability and mechanical property of an epoxy resin cured product. Chinese patent CN101333286B discloses a synthesis method of a cardanol aldehyde amine epoxy curing agent, wherein the cardanol aldehyde amine epoxy curing agent has a long alkyl-substituted chain with good hydrophobicity and flexibility, so that the curing agent has excellent water resistance and flexibility. Chinese patent CN101676316A discloses a method for preparing an oil-water epoxy resin curing agent for cashew nut shells, which comprises the steps of end-capping triethylene tetramine with a monoepoxide compound, and adding cardanol into the product to prepare a curing agent. The prior art emulsifies epoxy resin to prepare waterborne epoxy, which is a technical line, and then forms a reaction system with a common curing agent, while in the process of emulsifying epoxy, a plurality of cosolvents are added more or less, so that a real solvent-free environment-friendly system cannot be achieved. CN 110128630A shows urushiol diglycidyl ether in a waterborne epoxy curing agent. The solvent-free process cannot be carried out by the subsequent users as long as the solvent is added.

Disclosure of Invention

The invention aims to provide a water-based epoxy curing agent and a preparation method thereof; in particular to a solvent-free waterborne epoxy curing agent: can react with pure bisphenol A epoxy resin or other epoxy resin, does not need to be matched with aqueous epoxy resin for use, and avoids 1.5-5 percent of cosolvent contained in the aqueous epoxy.

The technical scheme of the invention is that the waterborne epoxy curing agent adopts a mixed emulsifier, and the emulsifier is provided with a hydrophilic group and a lipophilic group; the mixed emulsifier is then reacted with fatty amine curing agent and compounded with water to compound water-thinned curing agent. The reactive emulsifier is a mixture of acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether, and the weight ratio is as follows: 30-70-30; the aliphatic polyamine in the aliphatic amine curing agent comprises at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine. 1000PPM of polymerization inhibitor (various phenols) may be added.

The mixed emulsifier adopts acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol polyoxyethylene ether; stirring and mixing at 80 +/-15 ℃;

the second step of the preparation of the curing agent comprises the following steps: mixing type emulsifier: aliphatic polyamine is synthesized at about 60 +/-15 ℃ with the weight ratio of 1: 1.5-2.5, and water is added to prepare aqueous solution. The aliphatic polyamine is at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and diethylaminopropylamine.

The application of the invention is as follows: reaction system: pure epoxy resin: forming a solvent-free water-based reaction system by using a solvent-free curing agent which is 1: 1-1.5;

the water-based epoxy curing agent prepared by the invention has excellent water solubility, is mainly applied to modification of various water-based resins and can be prepared into water-based epoxy emulsion with the average particle size of less than or equal to 0.5um and the average particle size of less than or equal to 1.0um, is stable at normal temperature, is baked and cured at low, medium and high temperatures, and can be used as baking coatings, hydrophilic coatings, adhesives and the like.

The reactive emulsifier adopts acrylamide isopropyl sodium sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether in a weight ratio of: 30-70 to 70-30.

The water-based epoxy system is a dispersed phase structure and consists of water-based epoxy resin, a water-based epoxy curing agent, water and other multiple phases, the film forming mechanism of the water-based epoxy system is different from the film forming mechanism of a common polymer emulsion coating such as acrylic emulsion and can be condensed into a film, the film forming mechanism is not completely the same as the film forming mechanism of a solvent-based epoxy coating, in the solvent-based epoxy system, the epoxy resin and the curing agent are dissolved in an organic solvent in a molecular form, the formed system is homogeneous, the curing reaction is carried out among molecules, so the curing reaction is relatively complete, and the formed cured product is homogeneous. The aqueous epoxy is a multiphase system, the epoxy resin and the curing agent are dispersed in the water phase in a disperse phase, and the cross-linking and curing process is an interpenetration and internal diffusion cross-linking reaction process among particles in the process of water evaporation, so the curing degree of the aqueous epoxy depends on the following four factors: a) compatibility: the better the compatibility of the waterborne epoxy resin and the waterborne epoxy curing agent is, the better the compatibility is, the more the mutual internal diffusion of the curing agent particles and the epoxy resin particles is facilitated, and the proceeding of the curing reaction is facilitated; b) particle size: when the particle size is smaller, the waterborne epoxy resin and the waterborne epoxy curing agent disperse phase particles can fully interpenetrate to the inner core so as to achieve more complete curing degree; c) hydrophilic lipophilic balance value: the hydrophilic-lipophilic balance values of the waterborne epoxy resin and the waterborne epoxy curing agent are close to each other, the components reach a consistent coexistence state in the water phase, and if the difference is large, the components with strong hydrophilicity gradually gather in the water phase, so that the resin phase and the curing agent are separated; d) degree of dispersion uniformity: under the condition of multi-phase separation, the resin phase and the curing agent phase can be more uniformly distributed in the water phase only through a certain mechanical stirring action; the epoxy resin is very important to be uniformly stirred and mixed in application, and the curing process is easy to control and the reaction is complete.

Has the advantages that: the curing agent in the prior art forms a reaction system, and more or less cosolvent is added in the process of emulsifying epoxy, so that a real solvent-free environment-friendly system cannot be achieved. The invention can be used as a curing agent of all epoxy emulsification systems, has no solvent addition, has excellent water solubility, is mainly applied to modification of various water-based resins, has the average particle size of less than or equal to 0.5um and the average particle size of less than or equal to 1.0um, and is stable at normal temperature, and is baked and cured at low, medium and high temperatures. The curing agent has the following novel properties: the epoxy resin can react with pure bisphenol A epoxy resin or flexible epoxy resin, and does not need to be matched with waterborne epoxy resin for use, so that 1.5-5% of cosolvent (completely solvent-free can achieve real green in the production process) contained in waterborne epoxy is avoided, and a real solvent-free waterborne epoxy curing system is realized. And the brittleness of the water-based epoxy curing agent is overcome, and the using effect is good.

The waterborne epoxy curing agent and the preparation method thereof provided by the invention have the advantages that the method is simple to operate, and the raw material source is wide; the waterborne epoxy curing agent prepared by the method can improve the toughness and mechanical property of the epoxy resin material. And can obtain a water-based epoxy curing agent for curing epoxy resin at low temperature (less than 70 ℃). The weight ratio of the epoxy resin composition to the epoxy resin A component (such as bisphenol A, which is also used in other steps) is 1: 1-1.5. Pure epoxy can react, and the formed reaction system is absolutely solvent-free and environment-friendly. The packaging material (the invention is especially used for packaging glue of high-temperature batteries) adopts resin with high epoxy value (>0.40), such as E20(601) and E44 (6101).

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The epoxy resin raw materials in the examples of the present application were purchased commercially unless otherwise specified. The formula and the application are as follows:

emulsifier: aliphatic polyamine is synthesized at about 60 +/-15 ℃ in a ratio of 1: 1.2-1.3, and then water is added to prepare an aqueous solution.

The reactive emulsifier adopts acrylamide isopropyl sodium sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether in a weight ratio of: 30-70-30;

curing agent of the invention (solid content without water): the epoxy resin is 100: 100-150.

According to another aspect of the present application, there is also provided a method for preparing a water-based epoxy curing agent, comprising at least the following steps:

in the preparation method of the waterborne epoxy curing agent provided by the application, the waterborne epoxy curing agent is the waterborne epoxy curing agent.

The mixed emulsifier adopts acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol-polyoxyethylene ether in a weight ratio of 3: 7; stirring and mixing the mixture for 30 minutes at the temperature of 80 ℃ to obtain 100; the second step of the preparation of the curing agent comprises the following steps: mixing type emulsifier: aliphatic polyamine 100:120 weight portions, synthesizing at 60 ℃, stirring for 20 minutes, and adding 20 portions of water to prepare aqueous solution. The aliphatic polyamine is at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and diethylaminopropylamine. 1000PPM of hydroquinone polymerization inhibitor can be added.

Acrylamide sodium isopropyl sulfonate and polyacrylamide fatty alcohol polyoxyethylene ether, 5:5 weight parts.

Curing agent of the invention (solid content without water): the epoxy resin can be hydantoin epoxy resin or bisphenol A (S) epoxy resin 100: 100; when the epoxy resin is used for packaging materials (particularly for packaging glue of a high-temperature battery), the epoxy resin with a high epoxy value (>0.40) is adopted, such as E20(601) and E44 (6101). The amines are used in amounts of MG/Hn, where M is the molecular weight of the amine, Hn is the number of active hydrogens, and G is the epoxy number (equivalents of epoxy per 100G of epoxy resin) does not vary from 10 to 20%, which, if cured with excess amine, can embrittle the resin. If the amount is too small, the curing is incomplete.

The ammonia value is tested by adopting a test method of the total ammonia value of the JIS K7237-1995 epoxy resin amino hardener, the solid content is tested by adopting the GB/T2793-1995 adhesive non-volatile content, and the viscosity is tested by adopting a GB/T22314-. The viscosity (mPa. s, 25 ℃) can be controlled at 800-2000 ℃.

The curing agent has the following novel properties: the epoxy resin can react with pure bisphenol A epoxy resin or flexible epoxy resin, and does not need to be matched with waterborne epoxy resin for use, so that 1.5-5% of cosolvent contained in waterborne epoxy is avoided, and a real solvent-free waterborne epoxy curing system is realized.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.