US4375441A
Expired / Lapsed
US
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Method for producing sintered porous polymeric articles
Assignee: Standard Oil Co
•
Filing: 1980-12-18
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Granted: 1983-03-01
•
Expires: 2000-12-18
Abstract
Abstract A process for forming sintered porous polymeric articles by the steps of sintering preforms of polymeric particles with dielectric heat, or with dielectric heat in combination with conventional heating techniques. Sintered porous polymeric articles made of rubber-modified nitrile resins in accordance with the foregoing processes are also disclosed.
Inventors
- 👤 Richard C. Adams
- 👤 Albert J. Herold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:01
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/02; B29C67/04; B29C67/20; B29C67/205; C; C08; C08J; C08J9/00; C08J9/24
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
79 words
A method for producing a sintered porous polymeric article from a polymeric material with a sufficiently high loss factor for effective dielectric heating comprising: forming a preform comprising a plurality of discrete polymeric particles compressed together in a predetermined shape; and sintering said preform to form said article, said sintering step including the step of heating said preform using dielectric heating, said sintering step being conducted for a sufficient period to provide said article with desired strength and porosity.
Claim 2
Independent Claim
79 words
A method for producing a sintered porous polymeric article from a polymeric material with a sufficiently high loss factor for effective dielectric heating comprising: forming a preform comprising a plurality of discrete polymeric particles compressed together in a predetermined shape; and sintering said preform to form said article, said sintering step including the step of heating said preform using dielectric heating, said sintering step being conducted for a sufficient period to provide said article with desired strength and porosity.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said sintering step includes the step of heating said preform using conventional heating.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein said conventional heating step precedes said dielectric heating step.
Claim 5
Dependent Claim
15 words
The method of claim 2 wherein said dielectric heating step precedes said conventional heating step.
Claim 6
Dependent Claim
31 words
The method of claim 1 wherein said preform includes up to 100% by weight coarse particles, said coarse particles being small enough to pass through a No. 16 Tyler mesh sieve.
Claim 7
Dependent Claim
21 words
The method of claim 5 wherein said coarse particles are small enough to pass through a No. 70 Tyler mesh sieve.
Claim 8
Dependent Claim
29 words
The method of claim 1 wherein said preform includes up to 100% by weight fines, said fines being small enough to pass through a No. 240 Tyler mesh sieve.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein said preform comprises between about 5% to about 25% by weight particle fines.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein said preform comprises up to about 25% by weight of water.
Claim 11
Dependent Claim
18 words
The method of claim 9 wherein said preform comprises about 1% to about 10% by weight of water.
Claim 12
Dependent Claim
15 words
The method of claim 9 wherein said preform comprises about 5% by weight of water.
Claim 13
Dependent Claim
25 words
The method of claim 1 wherein said preform is formed in a mold with a pressure of up to about 10,000 pounds per square inch.
Claim 14
Dependent Claim
29 words
The method of claim 12 wherein said preform is formed in a mold with a pressure in the range of about 100 to about 4000 pounds per square inch.
Claim 15
Dependent Claim
30 words
The method of claim 1 wherein said dielectric heating step is conducted with microwaves of electromagnetic energy having a frequency in the range of about 890 to about 10,000 MHz.
Claim 16
Dependent Claim
25 words
The method of claim 2 wherein said conventional heating is conducted at a temperature in the range of about 120° C. to about 230° C.
Claim 17
Dependent Claim
25 words
The method of claim 15 wherein said conventional heating is conducted at a temperature in the range of about 160° C. to about 200° C.
Claim 18
Dependent Claim
18 words
The method of claim 1 wherein said dielectric heating step takes about one second to about two minutes.
Claim 19
Dependent Claim
17 words
The method of claim 17 wherein said dielectric heating step takes about 5 to about 40 seconds.
Claim 20
Dependent Claim
18 words
The method of claim 2 wherein said conventional heating step takes about two minutes to about 60 minutes.
Claim 21
Dependent Claim
16 words
The method of claim 19 wherein said conventional heating takes about 15 to about 30 minutes.
Claim 22
Dependent Claim
31 words
The method of claim 1 wherein said dielectric heating step is conducted with high-frequency waves of electromagnetic energy having a frequency in the range of about one to about 200 MHz.
Claim 23
Dependent Claim
16 words
The method of claim 1 wherein the loss factor of said polymeric material exceeds about 0.08.
Claim 24
Dependent Claim
16 words
The method of claim 1 wherein the loss factor of said polymeric material exceeds about 0.2.
Claim 25
Independent Claim
16 words
The method of claims 1 or 2 wherein said polymeric material comprise a rubber-modified nitrile resin.
Claim 26
Dependent Claim
196 words
The method of claim 24 wherein said polymeric material comprise a resin resulting from the polymerization of 100 parts by weight of (a) at least 50% by weight of at least one nitrile having the structure ##STR7## wherein R is hydrogen, a lower alkyl group having from 1 to 4 carbon atoms, or a halogen, and (b) up to 50% by weight based on the combined weight of (a) and (b) of an ester having the structure ##STR8## wherein R 1 is hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a halogen, and R 2 is an alkyl group having from 1 to 6 carbon atoms, in the presence of from 1 to 40 parts by weight of (c) a polymer of about 50% to 100% by weight of a conjugated diene monomer selected from the group consisting of butadiene and isoprene and about 0% to 50% by weight of at least one member selected from the group consisting of styrene, an olefinically unsaturated nitrile having the structure ##STR9## wherein R has the foregoing designation and an ester having the structure ##STR10## wherein R 1 and R 2 have the foregoing designations.
Claim 27
Dependent Claim
9 words
The method of claim 25 wherein (a) is acrylonitrile.
Claim 28
Dependent Claim
10 words
The method of claim 25 wherein (b) is methyl acrylate.
Claim 29
Dependent Claim
14 words
The method of claim 25 wherein (c) is a copolymer of butadiene and acrylonitrile.
Claim 30
Dependent Claim
73 words
A continuous process for forming sintered porous polymeric articles from a polymeric material with a sufficiently high loss factor for effective dielectric heating comprising: forming a preform comprising a continuous length of packed discrete polymeric particles of said polymeric material; sintering said preform in a sintering step comprising the step of heating said preform using dielectric heating; and comminuting the sintered preform from the previous step to form discrete sintered porous polymeric articles.
Claim 31
Dependent Claim
73 words
A continuous process for forming sintered porous polymeric articles from a polymeric material with a sufficiently high loss factor for effective dielectric heating comprising: forming a preform comprising a continuous length of packed discrete polymeric particles of said polymeric material; sintering said preform in a sintering step comprising the step of heating said preform using dielectric heating; and comminuting the sintered preform from the previous step to form discrete sintered porous polymeric articles.
Claim 32
Dependent Claim
19 words
The method of claim 29 wherein said sintering step includes the step of heating said preform using conventional heating.
Claim 33
Dependent Claim
15 words
The method of claim 30 wherein said conventional heating step precedes said dielectric heating step.
Claim 34
Dependent Claim
15 words
The method of claim 30 wherein said dielectric heating step precedes said conventional heating step.
Claim 35
Dependent Claim
18 words
The method of claim 29 wherein said forming step comprises extruding discrete polymeric particles to form said preform.
Claim 36
Independent Claim
16 words
The method of any of claims 29-33 wherein said polymeric material is a rubber-modified nitrile resin.
Claim 37
Independent Claim
198 words
The method of any of claims 29-33 wherein said polymeric material comprises a resin resulting from the polymerization of 100 parts by weight of (a) at least 50% by weight of at least one nitrile having the structure ##STR11## wherein R is hydrogen, a lower alkyl group having from 1 to 4 carbon atoms, or a halogen, and (b) up to 50% by weight based on the combined weight of (a) and (b) of an ester having the structure ##STR12## wherein R 1 is hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a halogen, and R 2 is an alkyl group having from 1 to 6 carbon atoms, in the presence of from 1 to 40 parts by weight of (c) a polymer of about 50% to 100% by weight of a conjugated diene monomer selected from the group consisting of butadiene and isoprene and about 0% to 50% by weight of at least one member selected from the group consisting of sytrene, an olefinically unsaturated nitrile having the structure ##STR13## wherein R has the foregoing designation and an ester having the structure ##STR14## wherein R 1 and R 2 have the foregoing designations.
Claim 38
Dependent Claim
9 words
The method of claim 35 wherein (a) is acrylonitrile.
Claim 39
Dependent Claim
10 words
The method of claim 35 wherein (b) is methyl acrylate.
Claim 40
Dependent Claim
14 words
The method of claim 35 wherein (c) is a copolymer of butadiene and acrylonitrile.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-28 | 1986-08-30 | 1987-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-28 | 1990-08-30 | 1991-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-28 | 1994-08-30 | 1995-03-01 | $7700.00 | Window Closed / Lapsed |