The Waterborne Acrylic Resin Modified By Eleostearic Acrylic Glyceride And Its Applied Performance

In consideration of the film of waterborne acrylic resin(WAR) has shortcomings of high water absorption and poor heat resistance, which lead researchers to modify the WAR to improve its comprehensive properties. Tung oil is a kind of renewable vegetable oil that has the characteristics of good adhesion, efficient water proofing and heat resistance. Besides, the three conjugated carbon bonds and carboxylic group in tung oil molecules can occur chemical reaction. Preparing tung oil-based WAR by synthesizing tung oil derivative and introducing it into WAR can improve water resistance, solvent resistance, heat resistance of WAR film, enhance the added value of tung oil and bring good social and economic benefit at the same time.Two-step method was employed to synthesize eleostearic glycidyl ester with tung oil as the raw materia then preparing eleostearic acrylic glyceride by reacting with acrylic acid. Using eleostearic acrylic glyceride as reactive monomer to synthesis WAR and then preparing the two component tung oil-based waterborne acrylic polyurethane wood varnish. The research results were as follows:1. Two kinds of tung oil derivatives were synthesized with tung oil as raw material——eleostearic glycidyl ester and eleostearic acrylic glyceride:Two-step method was employed to synthesize eleostearic glycidyl ester:The first step was controlling tung oil and potassium hydroxide mole ratio was 1:3.3, the ratio of solvent volum and tung oil mass was 3:1(mL/g), reacting for 2 h in 90%(v/v) methanol solution as solvent, the white eleostearic potassium was obtained. The second step was absolute ethyl alcohol as solvent, the ratio of solvent volum and eleostearic potassium mass was 4:1(mL/g), eleostearic potassium and epichlorohydrin mole ratio was 1:4, reacting for 4 h, the yield of eleostearic glycidyl ester would reach 92% and its epoxy value would be 4.7 which was very near to the theoretical value 4.8 and the total yield of the two step was nearly 75%.Eleostearic acrylic glyceride was synthesized and the appropriate conditions were:tetrabutyl ammonium bromide as catalyst, hydroquinone as polymerization inhibitor, eleostearic glycidyl ester and acrylic acid mole ratio was 1:1.1 and 110℃ reacted for 2 hours, the yellow product eleostearic acrylic glyceride was obtained and the esterification rate would reach 97%.2. Utilizing eleostearic acrylic glyceride to modify WAR, and then preparing two component tung oil-based waterborne acrylic polyurethane wood varnish:Eleostearic acrylic glyceride to modify WAR, the properties of the tung oil-based WAR film were the best when the content of eleostearic acrylic glyceride was 8%. The heat resistance was enhanced and the first decomposed temperature improved 50 ℃, pencil hardness was 2H, adhesion was 1 grade, storage time would reach 180 d.Two component tung oil-based waterborne acrylic polyurethane wood varnish was prepared. Using Bayhydur 305 to be the curing agent, tung oil-based WAR be the film forming material, the mole ratio of -NCO and -OH was 1.5:1.0, the heat resistance of the resin was improved, the glass transition temperature increased nearly 20℃ and the second decomposed temperature rate increased nearly 50℃. Besides, the surface of film was smooth, glossiness was 88°, pencil hardness was 2H, water resistance would reach 48 h, and other properties could also reach one level application demand.Eleostearic glycidyl ester and eleostearic acrylic glyceride were synthesized in this work. Eleostearic acrylic glyceride was introduced to modify WAR, and then prepared two component tung oil-based waterborne acrylic polyurethane wood varnish. The work developed the application domain of tung oil.