| The solvent-free two-component polyurethane PU membrane adhesive has been synthesized in this paper. The main agent is modified polyester polyol, and the curing agent is the adduct of isocyanate and polyether polyols. The effects of reactants, reactants ratio, reaction time, reaction temperature and process etc. on the main agent and the curing agent are discussed. The optimum process condition has been obtained, and the application research is done in this paper.Firstly, the main agent is polyester polyols with different modification. The effects of reactants, early reaction time, thermal dehydration time, highest reaction temperature, acid-alcohol mole ratio and Castor oil content etc. are researched. The optimum synthesis condition has been obtained as follows. The main agent1is the polyester polyol synthesized by Castor oil modified phthalic anhydride and Diethylene glycol, and the optimum synthesis condition has been obtained as:early reaction time3.5h, thermal dehydration time2h, highest reaction temperature210℃,a total reaction time8h, n(Diethylene glycol):n(phthalic anhydride)=1.7:1, Castor oil content30%. The main agent2is the polyester polyol synthesized by Castor oil modified Phthalic anhydride adipic acid and neopentyl glycol, and the optimum synthesis condition has been obtained as:early reaction time3.5h, thermal dehydration time2h, highest reaction temperature210℃, a total reaction time8.5h, acid-alcohol mole ratio1.6:1, n(phthalic anhydride):n(adipic acid)=1.5:1, Castor oil content30%. The main agent3is the polyester polyol synthesized by Castor oil modified Phthalic anhydride adipic acid and1,4butanediol, and the optimum synthesis condition has been obtained as:early reaction time3.5h, thermal dehydration time2h, highest reaction temperature210℃, a total reaction time8h, acid-alcohol mole ratio1.6:1, n(phthalic anhydride):n(adipic acid)=1:1, Castor oil content30%. The FTIR representation and the main agent hydroxyl value determination results shows that, the preparation of modified polyester polyols with hydroxyl sealing end is successful.Secondly, the curing agent is prepolymer with isocyanate base sealing side. The effects of polyether diols (PPG) molecular weight, isocyanate type, inhibitor type,-NCO content etc. are researched. The optimum synthesis condition has been obtained and represented by FTIR. The optimum process condition has been obtained through experiment as follows:PPG2000/PPG400mole ratio1:1, diphenyl methane diisocyanate (MDI) as reactant, NCO%=18%, reaction temperature45℃, reaction time3h, benzoyl chloride dosage1.0～1.2%. The product has been represented by FTIR as follows:3470cm-1vibration peak where-OH lies basically disappeares, free-NCO peak appears at2274cm-1Urethane carbonyl group Stretching vibration peak appears at1727cm-1, which means the preparation of polyurethane prepolymer with isocyanate base sealing side is successful.Thirdly, the solvent-free two-component polyurethane membrane adhesive is obtained by compounding the main agent and curing agent according to a certain ratio, and the effects of compounding ratio, curing time and curing temperature on peel strength are researched. The results are as follows. The optimum compounding condition of main agent1and curing agent is as:compounding ratio R’=1.9, curing temperature50℃, curing time24h. Test result shows the BOPP/MCPP peel strength is maximal at this time and can’t be peeled, and the glass transition temperature of PU membrane adhesive is7.19℃. The optimum compounding condition of main agent2and curing agent is as:compounding ratio R’=1.7, curing temperature50℃, curing time24h. Test result shows the BOPP/MCPP peel strength is maximal at this time and can’t be peeled, and the glass transition temperature of PU membrane adhesive is1.47℃. The optimum compounding condition of main agent3and curing agent is as:compounding ratio R’=1.5, curing temperature50℃, curing time24h. Test result shows the BOPP/MCPP peel strength is maximal at this time and can’t be peeled, and the glass transition temperature of PU membrane adhesive is-6.83℃. The peel strength performances of PU membrane adhesive and imported hydroxyl component adhesive are compared, and the PU membrane can reach the imported level.Finally, taking polyether or polyester polyol modified PAPI synthesized-NCO prepolymer as curing agent, and taking castor oil as main agent, then the solvent-free two-component PU structural adhesives is obtained by compounding the main agent and curing agent according to a certain proportion. Polyether modified PAPI synthesized prepolymer is curing agent1. Through single factor investigation of the effects of different molecular weight PPG and-NCO content on prepolymer viscosity and adhesive performance etc., the optimum process condition has been obtained as follows:-NCO%content20%, PPG1000modified PAPI prepolymer viscosity suitable and peel strength best. Polyester modified PAPI synthesized prepolymer is curing agent2. Through single factor investigation of the effects of different molecular weight polyester polyol and-NCO content on prepolymer viscosity and adhesive performance etc., the optimum process condition has been obtained as follows:-NCO%content25%, polyester polyol modified PAPI prepolymer viscosity suitable and peel strength best. Taking castor oil as main agent, the solvent-free two-component PU structural adhesives is obtained by compounding the main agent and curing agent according to a certain proportion. The effects of filler, curing temperature and two component compounding ratio etc. on PU structural are discussed, and the results show as follows. The optimum compounding condition of castor oil and curing agent1is as: coumpounding ratio R’=1.5, filler content230%, curing temperature50℃. The optimum compounding condition of castor oil and curing agent2is as:coumpounding ratio R’=1.7, castor oil and polyester polyol ratio3:1, filler content210%, curing temperature50℃... |
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