Single-component aqueous epoxy resin emulsion capable of being self-cured at normal temperature, and preparation method thereof

Abstract

The invention discloses single-component aqueous epoxy resin emulsion capable of being self-cured at normal temperature, and a preparation method thereof. The method comprises the following steps of: adding epoxy resin, n-butyl alcohol, and ethylene glycol monobutyl ether into a reactor, heating to form a homogeneous phase, controlling temperature to be 110 to 120 DEG C, and dripping acrylic ester monomers in which initiator benzoyl peroxide (BPO) is dissolved to obtain an acrylic ester monomer modified epoxy resin; and heating the acrylic ester monomer modified epoxy resin to 120 to 150 DEG C, adding unitary unsaturated fatty acid and catalyst triphenylphosphorus, adding maleic anhydride, reacting for 1.0 to 2.0 hours, reducing temperature to 50 to 55 DEG C, adding triethylamine, neutralizing for 0.5 to 1.0 hour, adding water and dispersing for 0.5 to 1.0 hour to obtain the single-component aqueous epoxy resin emulsion capable of being self-cured at normal temperature. The aqueous epoxy resin emulsion which is obtained by the method can be cured at normal temperature to form a film under the condition of not adding a curing agent, is convenient to use, and high in water resistance and corrosion resistance, and can be used for metal corrosion-resistant paint and the like.

Description

technical field [0001] The invention relates to a water-based epoxy emulsion, in particular to a normal-temperature self-drying water-based epoxy emulsion and a preparation method thereof. Background technique [0002] Epoxy resin has excellent adhesion, thermal stability, chemical resistance, insulation and mechanical strength, and is widely used in various fields such as coatings, adhesives and composite materials. Traditional epoxy resin coatings are generally solvent-based, and most of the organic volatiles are flammable, explosive and toxic substances, which are directly discharged into the atmosphere and seriously pollute the environment. In recent years, laws and regulations on environmental pollution restrictions have been promulgated one after another. Among them, there are two major issues concerning the emission restrictions of VOCs (Volatile Organic Compounds in Paint) and HAPs (Hazardous Air Pollutants) related to the coating industry. Coating zero VOC or low V...

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Problems solved by technology

The advantage of the water-based epoxy resin emulsion prepared by mechanical method is that the process is simple and the amount of emulsifier is less, but the size of the dispersed phase particles of epoxy resin in the emulsion is relatively large, about 50 μm, and the shape of the particles is irregular and the particle size distribution is wide. The prepared emulsion has poor stability, and the film-forming performance of the emulsion is not very good; the phase inversion method is to mix the added emulsifier and epoxy resin evenly under high-speed shearing, and then slowly mix them under certain shearing conditions. Add distilled water to the system, as the amount of water added, the whole system changes from water-in-oil to oil-in-water, forming a uniform and stable water-dilutable system. Due to the presence of emulsifiers, the hardness, water resistance, and solvent resistance of the coating film are improved. Poor properties such as resistance; more commonly used is the self-emulsification method, mainly through the introduction of hydrophilic groups in the epoxy resin and then neutralized to form a salt and add water to disperse, so that the epoxy resin is water-soluble, and the particle size is at the nanometer level. The operation process is convenient and the prepared epoxy resin has good stability and film-forming performance. This method has been paid more and more attention by people.

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