阅读说明：本技术 一种自乳化水性环氧乳液及其制备方法 (Self-emulsifying water-based epoxy emulsion and preparation method thereof ) 是由 臧圣彪 任率祖 程继业 王洪武 于 2018-08-28 设计创作，主要内容包括：本发明涉及一种自乳化水性环氧乳液及其制备方法。所述环氧乳液由包括重量份数为40-60复合乳化剂改性环氧树脂水性聚合物A及重量份数为40-60的去离子水制备得到。其包括如下步骤：一、复合乳化剂改性环氧树脂水性聚合物A的制备；二、复合乳化剂改性环氧树脂水性聚合物加水乳化,制备自乳化水性环氧树脂乳液。本发明制备的水性环氧树脂乳液,固含量高,乳液粒径小且均匀,稳定性好,乳液具有较好的稀释稳定性、抗盐稳定性、耐碱稳定性、高温稳定性、冻融稳定性、及良好的耐性等性能。可在涂料、粘合剂、碳纤维上浆剂等领域广泛应用。且其制备方法用料简单,合成过程简便易操作,且安全无毒。(The invention relates to a self-emulsifying water-based epoxy emulsion and a preparation method thereof. The epoxy emulsion is prepared from 40-60 parts by weight of composite emulsifier modified epoxy resin waterborne polymer A and 40-60 parts by weight of deionized water. Which comprises the following steps: firstly, preparing a composite emulsifier modified epoxy resin waterborne polymer A; and secondly, adding water to emulsify the composite emulsifier modified epoxy resin waterborne polymer to prepare a self-emulsifying waterborne epoxy resin emulsion. The aqueous epoxy resin emulsion prepared by the invention has high solid content, small and uniform emulsion particle size and good stability, and the emulsion has better dilution stability, salt resistance stability, alkali resistance stability, high temperature stability, freeze thawing stability, good tolerance and other properties. Can be widely applied in the fields of paint, adhesive, carbon fiber sizing agent and the like. And the preparation method has the advantages of simple material, simple and convenient synthetic process, easy operation, safety and no toxicity.)

1. The self-emulsifying water-based epoxy emulsion is characterized by being prepared from 40-60 parts by weight of composite emulsifier modified epoxy resin water-based polymer A and 40-60 parts by weight of deionized water; the water-based polymer A is obtained by reacting the following raw materials:

5-20 parts of ethylene glycol polyoxyethylene ether A1, preferably 10-15 parts;

3-10 parts by weight of bisphenol A polyoxyethylene (polyoxypropylene) ether A2, preferably 5-8 parts by weight;

2-10 parts by weight of diisocyanate A3, preferably 3-7 parts by weight;

60-90 parts by weight of epoxy resin A4, preferably 70-80 parts by weight;

the catalyst A5, the weight portion is 0.1-1, preferably 0.3-0.7.

2. The self-emulsifying aqueous epoxy emulsion according to claim 1, wherein the ethylene glycol polyoxyethylene ether A1 has a number average molecular weight of 1500 to 10000, preferably 3000 to 6000.

3. The self-emulsifying aqueous epoxy emulsion according to claim 2, characterized in that the ethylene glycol polyoxyethylene ether A1 is one or more of PEG1500, PEG3000, PEG4000, PEG6000, PEG8000 and PEG 10000.

4. The self-emulsifying aqueous epoxy emulsion according to claim 1, wherein the bisphenol a polyoxyethylene (polyoxypropylene) ether a2 has a number average molecular weight of 300 to 1000, preferably 400 to 800.

5. The self-emulsifying aqueous epoxy emulsion according to claim 4, wherein the bisphenol A polyoxyethylene (polyoxypropylene) ether A2 is any one of a block distribution containing only propylene oxide segments, only ethylene oxide segments or ethylene oxide and propylene oxide segments, preferably an ethylene oxide and propylene oxide segment block distribution, and has a repeating unit of 2 to 10.

6. The self-emulsifying aqueous epoxy emulsion according to claim 1, wherein said diisocyanate a3 is any of aliphatic, cycloaliphatic, aromatic and araliphatic diisocyanatesMeaning one or more, preferably HDI, H₁₂One or more of MDI, IPDI, TDI and TMXDI, more preferably H₁₂MDI。

7. The self-emulsifying aqueous epoxy emulsion according to claim 1, characterized in that the epoxy resin a4 is a bisphenol a type epoxy resin and/or a bisphenol F type epoxy resin, preferably one or more of E51, E44, E20 and E12, more preferably E20.

8. The self-emulsifying aqueous epoxy emulsion according to claim 1, wherein the catalyst a5 is any one of quaternary ammonium salt, triphenylphosphine, boron trifluoride etherate, and potassium persulfate.

9. A process for preparing the self-emulsifying aqueous epoxy emulsion according to any one of claims 1 to 8, characterized in that it comprises the following steps:

(1) preparation of the composite emulsifier modified epoxy resin waterborne polymer A: adding dehydrated ethylene glycol polyoxyethylene ether A1 and bisphenol A polyoxyethylene (polyoxypropylene) ether A2 into a reaction kettle, dropwise adding diisocyanate A3 after melting at 60-90 ℃, adding epoxy resin A4 and a catalyst A5 after NCO groups completely react at 60-90 ℃ in an inert atmosphere, continuing to react for 3-6 hours, and stopping the reaction after the epoxy value reaches the theoretical range to obtain a composite emulsifier modified epoxy resin waterborne polymer A;

(2) preparation of self-emulsifying aqueous epoxy emulsion: adding deionized water accounting for 10-45 wt% of the total amount of the deionized water into the composite emulsifier modified epoxy resin waterborne polymer A at 40-60 ℃, realizing phase inversion self-emulsification under strong stirring, and supplementing the rest deionized water after the phase inversion process is finished to prepare the self-emulsification waterborne epoxy emulsion.

10. The method of claim 9, wherein the resulting self-emulsifying aqueous epoxy emulsion has a solids content of from 40 wt% to 60 wt%.

Technical Field

The invention relates to the field of water-based paint, in particular to self-emulsifying water-based epoxy emulsion and a preparation method thereof.

Background

The epoxy resin contains a large amount of polar groups such as hydroxyl groups and ether bonds, has excellent adhesion to metal substrates, and the groups such as benzene rings and C-C chain segments endow the metal substrates with good heat resistance, corrosion resistance, toughness and the like. The modified epoxy resin is crosslinked with an amine curing agent to form a compact paint film with high crosslinking density, has excellent chemical resistance and salt spray resistance, and is widely applied to anticorrosive paint primer and intermediate paint. At present, most coatings are mainly solvent-based, easily generate a large amount of Volatile Organic Compounds (VOC), cause environmental pollution and have great harm to human bodies, so that the waterborne epoxy resin becomes the leading trend of future coatings, not only the VOC emission is greatly reduced, but also the more excellent performance is achieved.

Literature [ Macromolecules 2012, 45 (10): 4015-39] grafting styrene and methacrylic acid monomers onto high molecular weight epoxy resin, neutralizing, and then imparting strong hydrophilicity to the epoxy resin to prepare the aqueous epoxy resin emulsion. The method utilizes the free radical initiator, so that side reaction is easy to occur in the reaction process, and the method is not easy to control and has adverse effect on the performance of the emulsion.

Patent CN101177479A uses polyurethane modified epoxy resin to prepare aqueous epoxy emulsion, and the obtained emulsion has excellent water dispersibility and processability. However, the isocyanate is adopted for blocking in the synthesis process, so that the viscosity is too high, the gel is easy to gel, and the control is not easy.

In the literature, epoxy resin E-51 and Methyldiethanolamine (MDEA) are adopted to react under the heating condition, and then acetic acid is used for neutralizing tertiary amine to prepare quaternary ammonium salt emulsifier resin in [ coating industry ] 2013,43(1):39-43 ]; the water-based epoxy emulsion is prepared by the grafting reaction of the emulsifier resin and the epoxy resin and the dispersion. The grafting points of the method are too random, self-polymerization reaction is easy to occur among modifiers, and the quality of batch products cannot be effectively controlled.

Based on the defects, a new water-based epoxy emulsion and a preparation method thereof are needed, the defects of using an external emulsifier and insufficient performance of a single emulsifier are overcome, the prepared water-based epoxy emulsion has high solid content, small and uniform emulsion particle size and good stability, and the preparation method is simple in process operation, safe, non-toxic and easy for industrial production.

Disclosure of Invention

The first purpose of the invention is to provide a self-emulsifying water-based epoxy emulsion, which solves the defects of serious pollution and harm to human body of the current solvent-based epoxy coating and provides good performances of stability, tolerance and the like of the coating.

The second purpose of the invention is to provide the preparation method of the self-emulsifying water-based epoxy emulsion, which has the advantages of simple material, simple and convenient synthetic process, easy operation, safety and no toxicity.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a self-emulsifying waterborne epoxy emulsion is prepared from 40-60 parts by weight of composite emulsifier modified epoxy resin waterborne polymer A and 40-60 parts by weight of deionized water.

The water-based polymer A is obtained by reacting the following raw materials:

ethylene glycol polyoxyethylene ether A1, wherein the number average molecular weight of the ethylene glycol polyoxyethylene ether A1 is 1500-10000, the weight portion is 5-20, preferably the number average molecular weight is 3000-6000, and the weight portion is 10-15;

bisphenol A polyoxyethylene (polyoxypropylene) ether A2, wherein the number average molecular weight of the polyol A2 is 300-1000, the weight portion is 3-10, preferably the number average molecular weight is 400-800, and the weight portion is 5-8;

2-10 parts by weight of diisocyanate A3, preferably 3-7 parts by weight of diisocyanate A3;

the epoxy resin A4, wherein the weight part of the epoxy resin A4 is 60-90, preferably 70-80;

the catalyst A5, wherein the weight portion of the catalyst A5 is 0.1-1, preferably 0.3-0.7.

Preferably, the ethylene glycol polyoxyethylene ether A1 is one or more of PEG1500, PEG3000, PEG4000, PEG6000, PEG8000 and PEG 10000.

Preferably, the bisphenol A polyoxyethylene (polyoxypropylene) ether A2 is any one of a block distribution containing only Propylene Oxide (PO) (i.e. bisphenol A polyoxypropylene ether), a block distribution containing only Ethylene Oxide (EO) (i.e. bisphenol A polyoxyethylene ether) or EO and PO (i.e. bisphenol A polyoxyethylene polyoxypropylene ether), and the block distribution of PO and EO is preferably 2-10 of the repeating unit.

Preferably, the diisocyanate A3 is any one or more of aliphatic, cycloaliphatic, aromatic and araliphatic diisocyanates, more preferably HDI, H₁₂One or more of MDI, IPDI, TDI and TMXDI, more preferably H₁₂MDI。

Preferably, the epoxy resin a4 is a bisphenol a type epoxy resin and/or a bisphenol F type epoxy resin, preferably one or more of E51, E44, E20 and E12, more preferably E20.

Preferably, the catalyst A5 is any one of quaternary ammonium salt, triphenylphosphine, boron trifluoride diethyl etherate and potassium persulfate.

A preparation method of a self-emulsifying water-based epoxy emulsion comprises the following steps:

(1) preparation of the composite emulsifier modified epoxy resin waterborne polymer A: adding dehydrated ethylene glycol polyoxyethylene ether A1 and bisphenol A polyoxyethylene (polyoxypropylene) ether A2 into a reaction kettle, melting at 60-90 ℃, dropwise adding diisocyanate A3, adding epoxy resin A4 and catalyst A5 after NCO groups completely react at 60-90 ℃ in an inert atmosphere, continuing to react for 3-6h, and stopping the reaction after the epoxy value reaches a theoretical value (0.05-0.2mol/100g), thus obtaining the composite emulsifier modified epoxy resin waterborne polymer A;

(2) preparation of self-emulsifying aqueous epoxy emulsion: adding deionized water accounting for 10-45 wt% of the total amount of the deionized water into the composite emulsifier modified epoxy resin waterborne polymer A at 40-60 ℃, realizing phase inversion self-emulsification under strong stirring, and supplementing residual deionized water when the phase inversion process is finished (the phase inversion process is a process that the viscosity of the emulsion gradually increases along with the addition of water and suddenly decreases after a certain viscosity is reached), thereby preparing the self-emulsifying waterborne epoxy emulsion.

Preferably, the solid content of the obtained self-emulsifying water-based epoxy emulsion is 40-60 wt%.

The reaction process (1) is represented by the following chemical formula (taking bisphenol A epoxy resin as an example):

①

note: r1 is

②

Note: r1 is

R₂Is composed of

R₃Is composed of

R₄Is composed of

The basic principle of the invention is that: firstly, different polyoxyethylene ethers with emulsification are modified by virtue of diisocyanate, the defect of poor emulsification effect caused by an additional emulsifier or a single emulsifier and the combination of the two emulsifiers is avoided, and then the generated carbamate groups and epoxy resin epoxy groups are subjected to ring-opening reaction, so that epoxy resin without hydrophilicity can obtain emulsifier functional groups with strong hydrophilicity, and the water-based treatment is realized. The water-based epoxy resin prepared by the chemical modification method of the composite emulsifier has a self-emulsifying function, avoids the defects of insufficient performance of an external emulsifier and a single emulsifier, has high solid content of the obtained emulsion, small and uniform emulsion particle size, good stability, better dilution stability, salt resistance stability, acid and alkali resistance stability, high-temperature stability, freeze-thaw stability, tolerance and other performances, is simple to operate, is safe and non-toxic, and is easy for industrial production.

The invention has the beneficial effects that:

1. the self-emulsifying water-based epoxy emulsion has high solid content, small and uniform emulsion particle size and good stability, and in addition, the polyurethane group is introduced to endow the emulsion with more excellent tolerance. The water-based epoxy emulsion prepared by the invention can be suitable for water-based anticorrosive paint, water-based adhesive, fiber sizing agent and the like.

2. The self-emulsifying water-based epoxy emulsion and the preparation method thereof have the advantages of simple process, safe operation, low requirements on production equipment, cheap and easily obtained raw materials, and suitability for large-scale production.

The self-emulsifying water-based epoxy emulsion prepared by the invention has the following main properties:

(1) centrifugal stability: 3000r/min, no delamination and no demulsification in 30 min;

(2) storage stability: no demixing and no demulsification in 3 months;

(3) average particle size: 200-700 nm;

(4) salt-resistant stability: twice the amount of 5% CaC1 was added to the sample₂Adding the aqueous solution into the aqueous epoxy resin emulsion, and then standing for 48 hours, wherein the emulsion is stable and does not separate into layers and break emulsion;

(5) alkali resistance stability: adding 10% NaOH aqueous solution twice the amount of the sample into the emulsion, and standing for 48h, wherein the emulsion is stable and does not separate into layers and break emulsion;

(6) dilution stability: diluting the sample with distilled water twice the amount of the sample, standing at room temperature for 48h, and allowing the emulsion to be stable without layering and demulsification;

(7) high-temperature stability: heating at 60 deg.C for 3h, standing at room temperature for 3h, repeating the above steps for 5 times to obtain stable emulsion without delamination and emulsion breaking;

(8) freeze-thaw stability: freezing at-20 deg.C for 3h, standing at room temperature for 3h, repeating the above steps for 5 times, and making emulsion stable without layering and demulsifying.

Detailed Description

In order that the invention may be better understood, further details of the invention are set forth in the following examples.

Product name	Purchasing manufacturer
		Bisphenol A polyoxyethylene (polyoxypropylene) ether	Han agricultural chemistry
Diisocyanate	Wanhua chemistry
		Polyethylene glycol	Chemistry of Dow
Epoxy resin	Yuyang Ba Ling petrochemical