| Due to the increasingly stringent environmental protection policies,many solvent-based chemical products continue to withdraw from the historical stage,and the development of water-based environmental protection materials has been stimulated.The improvement of people’s living standards also makes people have higher requirements for environmental protection of furniture products,and has also contributed to the great development of water-based environmental protection wood paint.In this study,the acrylic acid dispersion with core-shell structure was prepared by using the good environmental weather resistance,good water resistance,alcohol resistance and dirt resistance of acrylate,and the aqueous polyurethane coating suitable for wood was prepared by reacting with polyisocyanate curing agent.The paint film properties are improved by increasing the hydroxyl value of the dispersion,so as to improve its physical and chemical properties such as hardness and gloss.The hydroxyl-containing aqueous acrylic acid secondary dispersion of two-component wood coatings was prepared by semi-continuous seed lotion method.The two-component polyurethane coating was prepared by reacting it with polyisocyanate curing agent and defoamer,and its performance was tested.The two-component polyurethane finish for self-made wood and the best coating scheme in the process of wood construction were explored,which maintained the gloss and wear resistance of wood coatings.The main results are as follows:(1)The acrylic acid,the ethylhexyl methacrylate,the styrene,the butyl methacrylate,the hydroxyethyl methacrylate and the butyl acrylate were copolymerized with the composite monomers.Then the hexafluorobutyl methacrylate and acrylate phosphate were used as functional monomers to play different roles.The propylene glycol butyl ether(PNB)and di tert butyl peroxide(DTBP)were used as hydrophilic solvent and initiator respectively.Finally,the secondary dispersion of acrylic acid for high hydroxyl waterborne coating was prepared by chain transfer agent thioethanol.At the same time,the secondary dispersion also had core-shell structure.In the polymer synthesis process,the effects of various factors such as the type and amount of initiator,the amount of chain transfer agent,the design of glass transition temperature and the environmental protection selection of solvent on the film-forming performance of the dispersion were discussed.Considering the influence of functional monomer participating in the reaction on the performance of the film,the relevant comparative experiments were carried out.The test results determined that the dosage of acid monomer was 3.5%of the total mass of monomers involved in the synthesis,the initiation dosage was 1.5%of the total mass of monomers involved in the synthesis,and the dosage of chain transfer agent was 1.0%of the total mass of monomers involved in the synthesis.(2)The thermogravimetric reaction analysis and thermal differential reaction analysis showed that the monomers in the polymer are involved in the copolymerization reaction,and the polymer formed has excellent thermal stability.Transmission electron microscope was used to observe that the synthesized dispersion polymer had an obvious core-shell structure,which successfully verified the successful realization of the dispersion particle structure designed in this experiment.(3)Taking the hydrophilic polymer formed by acrylic monomer as the core and the polymer of HEMA insoluble in water as the hydrophobic shell,the hydroxyl waterborne acrylic acid secondary dispersion with this core-shell structure is reactive crosslinked and cured with isocyanate curing agent,and then the diluent,defoamer,wetting dispersant,etc.are added to the mixed solution.The two-component polyurethane finish has excellent performance in the preparation of wood utensils.Finally,a series of performance tests were carried out to further optimize the structural formula of the varnish.So that it can finally achieve high gloss,including water resistance,which can meet the needs of the market.(4)Using the prepared two-component polyurethane wood finish with water-based primer and water-based sealing primer,the gloss and wear resistance experiments were carried out with pine as the substrate.The influence on wood paint film was studied through different coating amount,different peeling rate of rotary paint film and different spraying times.Finally,it is determined that the coating amount is 60g/m~2for water-based sealing primer,100g/m~2for water-based primer and 120g/m~2for self-made topcoat.Under the coating process achieved twice,the paint film effect is the best,which is suitable for the construction of self-made topcoat. |
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