Process for the production of polyvinyl butyral having improved properties
AssigneeE. I. Du Pont de Nemours and Company
InventorRobert Degeilh
Life of this patent
Estimating the term…
Abstract
A process for the preparation of a polyvinyl butyral having improved properties comprises subjecting a polyvinyl alcohol in an aqueous medium in the presence of butyraldehyde and an acid catalyst and ethoxylated alkylphenol sulfate having the formula C.sub.9 H.sub.19 --[O]C.sub.6 H.sub.4 --O--[]](CH.sub.2 --CH.sub.2 --O--[]]).sub.n SO.sub.3 Na where n=6 or n=7 effective as an emulsifier, neutralizing the reaction mixture to a pH of between 9 and 11, and thereafter recovering the polyvinyl butyral by separating it from the reaction liquor and thoroughly washing it with water.
Claims16
A process for producing polyvinyl butyral which comprises treating polyvinyl alcohol in an aqueous medium in the presence of an acid catalyst and an emulsifier of ethoxylated alkylphenol sulfate with butyraldehyde to form a reaction mixture,
- neutralizing the reaction mixture to raise the pH of the mixture to about 5,
- recovering polyvinyl butyral from the reaction mixture, and
- washing the polyvinyl butyral with water at ambient temperature to obtain polyvinyl butyral,
- wherein said emulsifier is an ethoxylated alkylphenol sulfate having the formula
- C.sub.9 H.sub.19 --C.sub.6 H.sub.4 --O--(CH.sub.2 --CH.sub.2 --O).sub.n --SO.sub.3 Na
- where n=6 or 7,
- said sulfate being present in an amount of between about 0.1 and 0.3 percent by weight of said polyvinyl alcohol,
- whereby said neutralizing step and recovery of polyvinyl butyral is performed in about 5 to 10 minutes.
A process for producing polyvinyl butyral which comprises:
- forming a reaction mixture of an aqueous solution of about 8 to 15 by weight percent polyvinyl alcohol with butyraldehyde in the presence of an acid catalyst and an ethoxylated alkylphenol sulfate emulsifier of from about 0.1 to 0.3 percent by weight calculated on polyvinyl alcohol at a temperature of from about 5.degree. to 12.degree. C. for a sufficient time to react about 75 to 88 percent of the polyvinyl alcohol in the mixture;
- agitating the reaction mixture;
- increasing the temperature of said mixture to from about 60.degree. to 80.degree. C. for at least about 11/2 hours;
- adding a base to the reaction mixture to neutralize the reaction mixture to a pH of at least about 9;
- washing the reaction mixture with water to completely remove the emulsifier;
- and
- recovering polyvinyl butyral.
In a process of preparing polyvinyl butyral from an aqueous solution of polyvinyl alcohol, butyraldehyde, an acid catalyst, and an emulsifier, the improvement which comprises reducing the curing time of polyvinyl butyral by utilizing ethoxylated alkyl phenol sulfate as the emulsifier in an amount of between about 0.1 and 0.3 percent by weight calculated on polyvinyl alcohol.
Dependencies are inferred from the claim text.