US4830810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of blow molding and fluorinating plastic containers
Assignee: Audi AG
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Filing: 1986-05-29
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Granted: 1989-05-16
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Expires: 2006-05-29
Abstract
Abstract A novel method of blow molding and fluorinating plastic containers carried out in essentially three steps, including blow molding of the container at a first predetermined pressure in a mechanically locked mold with an inert gas, testing the mold for pressure tightness at a second higher level of pressure with an inert gas, and thereafter introducing a fluorine containing gas into the mold at a third level of pressure.
Inventors
- 👤 Peter Ufer
- 👤 Siegfried Schaper
- 👤 Hans-Gunther Haldenwanger
- 👤 Ingrid Paulus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:24
CPC Classifications
B; B29; B29C; B29C49/00; B29C49/42; B29C49/46; B29C2049/4602; B29C2049/4605; B29C2049/4608; B29C2049/4611; B29C2049/4617; B29C2049/4623; B29C49/78; B29C49/783; B29C2049/7832; B29C49/4273; B29C71/00; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29L; B29L2031/00; B29L2031/712; B29L2031/7172
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
145 words
A method of blow molding and fluorinating a plastic container, comprising the steps of: inserting a blank of a container into an open mold having a cavity of predetermined shape; closing said mold; injecting an inert gas into said blank within said closed mold at a first predetermined pressure thereby to expand said blank and conform it to the shape of the cavity of said mold to form the container; checking said expanded blank for pressure tightness by monitoring said first predetermined pressure of said inert gas therein for a predetermined interval and thereby determining that said first predetermined pressure remains constant and that said expanded blank is not leaking; and, thereafter injecting a fluorine containing gas into said expanded blank at a second predetermined pressure in excess of said first predetermined pressure for a time sufficient to impart impermeability to the interior surface thereof.
Claim 2
Independent Claim
145 words
A method of blow molding and fluorinating a plastic container, comprising the steps of: inserting a blank of a container into an open mold having a cavity of predetermined shape; closing said mold; injecting an inert gas into said blank within said closed mold at a first predetermined pressure thereby to expand said blank and conform it to the shape of the cavity of said mold to form the container; checking said expanded blank for pressure tightness by monitoring said first predetermined pressure of said inert gas therein for a predetermined interval and thereby determining that said first predetermined pressure remains constant and that said expanded blank is not leaking; and, thereafter injecting a fluorine containing gas into said expanded blank at a second predetermined pressure in excess of said first predetermined pressure for a time sufficient to impart impermeability to the interior surface thereof.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said mold is hydraulically closed and additionally comprises mechanical latching means.
Claim 4
Dependent Claim
27 words
The method of claim 2, wherein the step of checking said expanded blank for pressure tightness comprises the step of checking the mechanical latching of said mold.
Claim 5
Dependent Claim
18 words
The method of claim 3, wherein said first predetermined pressure is between about 2 and about 4 bar.
Claim 6
Dependent Claim
14 words
The method of claim 4, wherein said first predetermined pressure is about 3 bar.
Claim 7
Dependent Claim
17 words
The method of claim 4, wherein said fluorine containing gas is injected commencing at about 4 bar.
Claim 8
Dependent Claim
22 words
The method of claim 6, wherein said fluorine containing gas is maintained in said blank at a pressure of about 10 bar.
Claim 9
Dependent Claim
23 words
The method of claim 7, wherein said fluorine containing gas is maintained at said pressure of about 10 bar for about 30 seconds.
Claim 10
Dependent Claim
34 words
The method of claim 8, wherein said step of injecting said fluorine containing gas into said expanded blank is followed by an additional step of venting said fluorine containing gas from said expanded blank.
Claim 11
Dependent Claim
19 words
The method of claim 9, wherein said venting is followed by repeated rinsings of said blank with inert gas.
Claim 12
Dependent Claim
10 words
The method of claim 10, wherein said blank comprises polyethylene.
Claim 13
Dependent Claim
25 words
The method of claim 11, wherein said step of injecting said fluorine containing gas into said blank results in a surface therein of fluorinated polyethylene.
Claim 14
Dependent Claim
17 words
The method of claim 12, wherein said fluorine containing gas comprises less than about 1.5% of fluorine.
Claim 15
Dependent Claim
12 words
The method of claim 13, wherein said fluorine containing gas comprises nitrogen.
Claim 16
Dependent Claim
12 words
The method of claim 14, wherein said injected inert gas comprises air.
Claim 17
Dependent Claim
13 words
The method of claim 14, wherein said injected inert gas comprises pure nitrogen.
Claim 18
Dependent Claim
13 words
The method of claim 16, wherein said container comprises an automotive fuel tank.
Claim 19
Dependent Claim
15 words
The method of claim 1, wherein said steps are carried out in about 120 seconds.
Claim 20
Dependent Claim
24 words
The method of claim 3, wherein said step of checking is carried out at a pressure within said expanded blank of about 3 bar.
Claim 21
Dependent Claim
15 words
The method of claim 13, wherein said fluorine containing gas comprises about 1% of fluorine.
References Cited (Backward Citations)
US2811468A
Cited
DE1905094A1
Cited
US3728063A
Cited
US3866841A
Cited
DE2401948A1
Cited
US4097565A
Cited
DE2644508A1
Cited
US4162878A
Cited
DE2924797A1
Cited
US4396567A
Cited
US4394333A
Cited
US4333905A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-15 | 1992-11-14 | 1993-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-15 | 1996-11-14 | 1997-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-15 | 2000-11-14 | 2001-05-16 | $7700.00 | Window Closed / Lapsed |