Process for preparing polyvinyl acetal by acid-catalyzed reaction

Patent metadata

Field	Value
Publication number	US-9303102-B2
Application number	US-201314102786-A
Country	US
Kind code	B2
Filing date	Dec 11, 2013
Priority date	Dec 18, 2009
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

The invention relates to polyvinyl acetals obtainable by reacting polyvinyl alcohol with at least one aldehyde with a degree of acetalization of at least 75 mol %, characterized by an OH blockiness of the polyvinyl acetal, defined as a quotient from the number of methylene groups of two adjacent alcohol sequences (VV) and the sum of the number of methylene groups of adjacent alcohol/acetal sequences and acetal/acetal sequences (VB+BB), of more than 0.151, as well as a process for the preparation thereof.

First claim

The invention claimed is:

1. A process for preparing a polyvinyl acetal by acid-catalyzed reaction of at least one polyvinyl alcohol with at least one aldehyde, said process comprising:
a) reacting said at least one polyvinyl alcohol with said at least one aldehyde at a temperature of 0 to 20° C.,
b) completing the reaction of a) by heating the resultant reaction mixture to 68 to 90° C.,
c) cooling the resultant reaction mixture to 15 to 25° C. and separating the polyvinyl acetal, and
d) neutralizing the polyvinyl acetal separated from the reaction mixture; and
wherein the resultant polyvinyl acetal has an OH blockiness, defined as a quotient from the number of methylene groups of two adjacent alcohol sequences (VV) and the sum of the number of methylene groups of adjacent alcohol/acetal sequences and acetal/acetal sequences (VB+BB), of more than 0.151.

2. The process according to claim 1 , wherein the temperature in b) is maintained over a period of at least 60 min.

3. The process according to claim 1 wherein the temperature in b) is 68° C. to 80° C.

4. The process according to claim 1 , wherein said process is conducted in the absence of emulsifiers or surfactants.

5. The process according to claim 1 , said at least one aldehyde is butyraldehyde.

6. The process according to claim 1 , wherein said polyvinyl acetal has a residual acetate content of 1.0 to 8 mol %.

7. The process according to claim 1 , wherein said polyvinyl acetal has an OH blockiness of from greater than 0.16 up to 0.3.

8. The process according to claim 1 , wherein said polyvinyl acetal has an OH blockiness of from greater than 0.17 up to 0.3.

9. The process according to claim 1 , wherein said polyvinyl acetal has an OH blockiness of from greater than 0.18 up to 0.3.

10. The process according to claim 1 , wherein said polyvinyl acetal has a residual acetate content of 1.0 to 5.0 mol %.

11. The process according to claim 1 , wherein said polyvinyl acetal has a residual acetate content of 1.0 to 2.0 mol %.

12. The process according to claim 1 , wherein the temperature in b) is maintained over a period of at least 80 min. up to 600 min.

13. The process according to claim 1 , wherein the temperature in a) is 12° C. to 20° C.

14. The process according to claim 1 , wherein the polyvinyl acetal has a melt flow rate (MFR) value, determined at the 100° C. using a 2 mm nozzle with weight loading of 21.6 kg, of 552-713 mg/10 min.

Assignees

• Kuraray Europe Gmbh

Inventors

• Steuer Martin
• Katayama Masako

Classifications

• B32B17/10761 Primary

  containing vinyl acetal · CPC title

• Y10T428/3163

  Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.] · CPC title

• C08F8/28 Primary

  Condensation with aldehydes or ketones · CPC title

• C08F8/48

  Isomerisation; Cyclisation · CPC title

• C08F16/06

  Polyvinyl alcohol {; Vinyl alcohol} · CPC title