Preparation Of Polyvinyl Butyral(PVB)

Polyvinyl butyral is a polymer compound(PVB)produced by the condensation reaction of polyvinyl alcohol(PVA)and n-butyraldehyde under acidic conditions.Because its molecular chain contains acetal,hydroxyl and a certain amount of ester groups.Therefore,the pressed film has a certain strength;it has high adhesion to metals and glass(especially aluminum)and has a certain degree of flexibility.This paper studies the main factors affecting the acetalization rate,hydroxyl value,and bulk density from three aspects.The experimental results show:(1)The reaction temperature,reaction time and acidity of the system are the main factors affecting the acetalization rate.When the reaction time is 7 to 8 hours,the reaction termination temperature is 60～65℃,and the acidity of the reaction system is 0.5～0.6%,the acetalization rate of PVB reaches the best range: 78～80%.(2)The reaction temperature,reaction time and acidity of the system are the main factors affecting the acetalization rate.When the reaction time is 6.5～7.5 h,the reaction termination temperature is 60～65℃,and the acidity of the reaction system is 0.4～0.6%,the hydroxyl value of PVB reaches the best range: 18.5%～19.5%.(3)Reaction time,reaction temperature and holding time are the main factors affecting the bulk density of PVB.When the reaction time is 6.5～7.5h,the reaction termination temperature is 50～55℃,and the bulk density of PVB reaches the best range when the holding time is 50～80min: 23.5～24.3(g/ml)(4)The compounding of multiple antioxidants can improve the thermal stability of PVB.By comparing a single antioxidant with a compounded antioxidant,it is concluded that the thermal stability of PVB with a compounded antioxidant is significantly better than that with PVB with a single antioxidant,and when the compounded antioxidant 1178,The thermal stability of PVB was best when 452 and 3g were added respectively...