Study On The Preparation And Performance Of Biomass Polyacid Modified Waterborne Alkyd Resin

Alkyd resin has the advantages of low production cost and excellent comprehensive performance of paint film and occupies a considerable proportion in coating resins.With the increasingly severe environmental protection laws,the use of traditional solvent-based coatings is becoming more and more restricted.Although the water-based alkyd resin coatings can reduce VOC emissions to a large extent,however,water-based alkyd resins also have the disadvantages of low hardness,slow drying speed,poor water resistance and salt water corrosion resistance.The purpose of this paper is to prepare a water-based alkyd resin with excellent comprehensive properties.For this purpose,the following researches are carried out in this paper:(1)The water-based alkyd resin was prepared from fatty acid,trimethylolpropane(TMP),isophthalic acid(IPA),trimellitic anhydride(TMA),etc.using the synthesis process of the melting method.The influence of synthesis process and formulation design on water-based alkyd resin was investigated.The study found that the material loss of the water-based alkyd resin is the smallest by using the gradient heating method.When the soy oleic acid is used as the raw material,the oil length is 40%,the excess alcohol is1.25,the initial acid value is 6-9 mg KOH/g,and the final acid value is45-55 mg KOH/g,the addition amount of TMA is 9%,the addition amount of ethylene glycol monobutyl ether(BCS)is 20%,the prepared water-based alkyd resin has the fastest drying rate,the highest hardness,and best storage stability and water resistance.(2)Preparation of waterborne alkyd resin by replacing part of IPA with biomass polyacid as modifier,the study found that the molecular weight of water-based alkyd resin modified by biomass polyacid is larger,the Tg of the prepared varnish film is lower,the water resistance and salt water resistance of the coating film are significantly improved,the water absorption rate of the coating film is reduced,the contact angle and gloss are significantly improved,and the resin varnish film before and after modification has good heat resistance below 150℃.when the addition amount of biomass polyacid is 6%,the resin paint film has the best comprehensive performance.(3)The waterborne alkyd resin was modified by the self-made epoxy ester,and the influence of the preparation process and formulation design of the epoxy ester on the performance of the waterborne alkyd resin was explored.The research results show that the larger the molecular weight of the epoxy resin,the longer the reaction time of the epoxy ester,and the epoxy ester modified waterborne alkyd resin prepared by the higher molecular weight E-44 and E-20 has better performance.When the epoxy ester prepared by E-44 is used for modification,and its addition amount is 15%,the paint film performance of the resin is better,the hardness is H,and slight yellowing in salt water immersion for 24 h.The epoxy ester was modified with phosphoric acid,biomass polyacid and itaconic acid instead of part of soya oleic acid.The study found that when the addition amount of itaconic acid was10%,it was found that the molecular weight of the prepared epoxy ester modified alkyd resin was higher,the performance of the paint film is better and no obvious change in salt water immersion for 24 h,and the Tg of paint film is lower,and the heat resistance of the paint film is better below 300℃.(4)Using the water-based alkyd resin of BPAE44IA-10 as the matrix resin,the influence of the formulation of the water-based alkyd resin coating on the performance of the coating was explored.The research indicates that when the defoamer is BYK-011 and the dosage is 0.2%;the leveling agent is KL-245 and the dosage is 0.3%;the thickener is PUR-62 and the dosage is0.25%;the viscosity adjusted to 1728 m Pa·s;the pigment-to-base ratio was controlled at 0.8,the prepared one-component biomass polyacid modified water-based alkyd resin antirust coating had a smooth paint film and had the best performance,the surface dryness is 20 min,the actual dryness is 16 h,the hardness is H,the water resistance is more than 196 h and salt spray resistance up to 192 h.