| 摘要 |
PCT No. PCT/US92/10510 Sec. 371 Date Feb. 17, 1995 Sec. 102(e) Date Feb. 17, 1995 PCT Filed Dec. 4, 1992 PCT Pub. No. WO94/13710 PCT Pub. Date Jun. 23, 1994A process for producing mixed poly(vinyl acetals) containing butyral acetal groups and long chain acetal groups derived from one or more aldehydes containing at least six C atoms, by conducting an acetalization reaction forming long chain acetal groups in the substantial of absence butyraldehyde until gel break occurs, adding butyraldehyde after gel break and continuing acetalization until the desired reaction endpoint is reached. Reaction temperature is from about 40 DEG C. up to the boiling point of water at the pressure of the acetalization reaction and preferably between about 75 DEG C. and about 98 DEG . |
