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Process for the gentle degasification of coagulation-sensitive PVC latices

Assignee: Wacker Chemie AG
•
Filing: 1977-07-07
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Granted: 1978-12-05
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Expires: 1997-07-07
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Abstract

Abstract In the process for the gentle degasification of coagulation-sensitive PVC latices in a confined space under reduced pressure and stirring at elevated temperatures with steam injection onto the latex surface, the improvement consisting essentially of conducting said degasification at a selected temperature from 50° C to 80° C at a pressure corresponding to the boiling pressure of water at the selected temperature, stirring said latex by an inclined stirrer whereby a rolling action of said latex in said confined space is effected and introducing said steam into the gas space above said latex but directed along the surface of the confined space.

Inventors

  • 👤 Hans Geschonke
  • 👤 Rainer Rompeltien
  • 👤 Wolfgang Rummel

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 06:25
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/001; C08F6/003

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 240 words
In the process for the gentle degasification of coagulation-sensitive PVC latices in a confined space under reduced pressure and stirring at elevated temperatures with steam injection onto the latex surface, the improvement consisting essentially of conducting said degasification at a selected temperature from 50° C. to 80° C. at a pressure corresponding to the boiling pressure of water at the selected temperature, stirring said latex by an inclined stirrer mounted in a perpendicular plane to the vessel wall and inclined from the vertical by an angle β of 20° to 45° in a clockwise direction, said inclined stirrer extending beyond the wall of said vessel by the length L said latex surface being between a minimum height H 1 , and a maximum height H 2 in said vessel having a diameter D, where the ratio of L to D is from 0.3 to 0.1, the ratio of the lower limit of H 1 is 0.3 > H 1 to D > 0.1, the ratio of the upper limit H.sub. 2 is 1 > H 2 to D > 0.2, said stirrer being situated so that effective stirring occurs at H 1 and H 2 is at about 50% of the total liquid capacity of said vessel, whereby a rolling action of said latex in said confined space is effected and introducing said steam into the gas space above said latex but directed along the surface of the confined space.
Claim 2
Dependent Claim 240 words
In the process for the gentle degasification of coagulation-sensitive PVC latices in a confined space under reduced pressure and stirring at elevated temperatures with steam injection onto the latex surface, the improvement consisting essentially of conducting said degasification at a selected temperature from 50° C. to 80° C. at a pressure corresponding to the boiling pressure of water at the selected temperature, stirring said latex by an inclined stirrer mounted in a perpendicular plane to the vessel wall and inclined from the vertical by an angle β of 20° to 45° in a clockwise direction, said inclined stirrer extending beyond the wall of said vessel by the length L said latex surface being between a minimum height H 1 , and a maximum height H 2 in said vessel having a diameter D, where the ratio of L to D is from 0.3 to 0.1, the ratio of the lower limit of H 1 is 0.3 > H 1 to D > 0.1, the ratio of the upper limit H.sub. 2 is 1 > H 2 to D > 0.2, said stirrer being situated so that effective stirring occurs at H 1 and H 2 is at about 50% of the total liquid capacity of said vessel, whereby a rolling action of said latex in said confined space is effected and introducing said steam into the gas space above said latex but directed along the surface of the confined space.
Claim 3
Dependent Claim 33 words
The process of claim 1 wherein said steam is directed along the surface of the confined space at an angle α of from 60° to 90° from the vertical in a clockwise direction.
Claim 4
Dependent Claim 30 words
The process of claim 1 wherein said steam is directed in a horizontally circular spray in substantially the center of said confined space to the surface of said confined space.
Claim 5
Dependent Claim 14 words
The process of claim 1 wherein said ratio of L to D is 0.2.
Claim 6
Dependent Claim 24 words
The process of claim 1 wherein said ratio of the upper limit H 2 is 1 > H 2 to D 0.3 to 0.5.
Claim 7
Dependent Claim 14 words
The process of claim 1 wherein said angle β is from 25° to 35°.
Claim 8
Dependent Claim 14 words
The process of claim 2 wherein said angle α is from 70° to 80°.
Claim 9
Dependent Claim 83 words
The process of claim 3 wherein said steam is directed in a horizontally circular spray by means of a circular baffle, parallel to the surface of the latex having a diameter d 1 placed at a distance h from the dome of said confined space having a diameter D, said confined space having a neck of diameter d at its top where the following ratios apply: 0.01 < d 1 /D < 0.05 0.05 < d/D < 0.2 0.02 < h/D < 0.05
Claim 10
Dependent Claim 35 words
The process of claim 8 where the ratio of d 1 to D is from 0.02 to 0.03, the ratio of d to D is 0.1 and the ratio of h to D is 0.03.
Claim 11
Dependent Claim 25 words
The process of claim 8 wherein said circular baffle has a lid set a distance S thereover and S is from 0.5 to 5 mm.
Claim 12
Dependent Claim 13 words
The process of claim 10 wherein S is from 1 to 2 mm.

References Cited (Backward Citations)

US2467769A Cited
US3129132A Cited
US4017445A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-12-04 1982-06-05 1982-12-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-12-04 1986-06-05 1986-12-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-12-04 1990-06-05 1990-12-05 $7700.00 Window Closed / Lapsed

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