Claims
- 1. A process for producing a polyvinyl acetacetal resin, sequentially comprising the steps of:
- initiating precipitation of an acetalated product by maintaining an emulsifier-free reaction system comprising a polyvinyl alcohol and acetaldehyde in an aqueous phase in the presence of 4-10% by weight of an acid catalyst in a first temperature range of 8.degree.-17.degree. C. for at least 30 minutes; and
- maintaining the reaction system in a second temperature range of 25.degree.-40.degree. C. to obtain the polyvinyl acetacetal resin.
- 2. The process of claim 1, wherein said acid catalyst comprises at least one acid selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid.
- 3. The process of claim 1, wherein said acetaldehyde is provided for the reaction in a proportion of 0.7 to 2.2 mols per 2 mols of said polyvinyl alcohol.
- 4. The process of claim 1, wherein the acetalation degree of said polyvinyl acetacetal resin is 60 mol % or higher.
- 5. The process of claim 1, wherein the acetalation degree of said polyvinyl acetacetal resin is 65 mol % or higher.
- 6. The process of claim 1, wherein the acetalation degree of said polyvinyl acetacetal resin is 70 mol % or higher.
Priority Claims (2)
Number |
Date |
Country |
Kind |
61-298505 |
Dec 1986 |
JPX |
|
62-45463 |
Feb 1987 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 07/132,001 filed Dec. 11, 1987, now U.S. Pat. No. 4,902,670.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4533697 |
Degeilh |
Aug 1985 |
|
4541830 |
Hotta et al. |
Sep 1985 |
|
4614521 |
Niwa et al. |
Sep 1986 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2007677 |
May 1979 |
GBX |
Divisions (1)
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Number |
Date |
Country |
Parent |
132001 |
Dec 1987 |
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