US4049588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of vulcanized rubber
Assignee: NRI Pennsylvania Inc
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Filing: 1975-12-09
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Granted: 1977-09-20
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Expires: 1995-12-09
Abstract
Abstract The invention provides finely divided vulcanized rubber having a particle size of generally less than 20 microns for re-use in the rubber industry. Vulcanizates produced from compositions containing the finely divided vulcanized rubber, either as the sole rubber component or in admixture with unvulcanized rubber, have properties significantly better than those of vulcanizates of similar compositions containing conventional reclaimed rubbers. Vulcanized rubber is converted into the finely divided rubber by the steps of (1) contacting vulcanized rubber with a fatty acid, (2) contacting the product of step (1) with a solid alkali and (3) forming a dispersion of the product of step (2) with a liquid which dissolves the alkali but does not affect the rubber. Alternatively, the finely divided vulcanized rubber results from the steps of (1) contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it e.g. tetrahydrofuran, (2) comminuting the weakened material and (3) removing the liquid from the comminuted material.
Inventors
- 👤 Timothy Charles Philip Lee
- 👤 William Millns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:03
CPC Classifications
C; C08; C08J; C08J11/00; C08J11/04; C08J11/06; C08J3/00; C08J3/12; C08L; C08L19/00; C08L19/003; C08J2321/00; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S241/00; Y10S241/31
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
78 words
A method of converting vulcanized rubber into finely-divided vulcanized rubber comprising: 1. contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it, 2. comminuting the weakened material into particles of said vulcanized rubber, at least 90% of said particles having a particle size less than 20 microns, said particles further being characterized by the property of separating out from an admixture with water, 3. removing said liquid from the comminuted material, and
Claim 2
Independent Claim
78 words
A method of converting vulcanized rubber into finely-divided vulcanized rubber comprising: 1. contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it, 2. comminuting the weakened material into particles of said vulcanized rubber, at least 90% of said particles having a particle size less than 20 microns, said particles further being characterized by the property of separating out from an admixture with water, 3. removing said liquid from the comminuted material, and
Claim 3
Dependent Claim
11 words
recovering the comminuted material in the form of a fine powder.
Claim 4
Dependent Claim
11 words
recovering the comminuted material in the form of a fine powder.
Claim 5
Dependent Claim
37 words
A method as claimed in claim 1 in step (1) of which the vulcanised rubber, in the form of thin sheets, shreds or crumb, is allowed to imbibe as much swelling liquid as it will take up.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 1 in which the liquid is a polar liquid.
Claim 7
Dependent Claim
14 words
A method as claimed in claim 3 in which the polar liquid is tetrahydrofuran.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 3 in which the polar liquid is methyl ethyl ketone, ethyl acetate or chloroform.
Claim 9
Dependent Claim
19 words
A method as claimed in claim 1 in step (3) of which the swelling liquid is removed by evaporation.
Claim 10
Dependent Claim
41 words
A method as claimed in claim 1 in step (3) of which a liquid which is miscible with the swelling liquid but not miscible with the rubber is added to the swelling liquid whereby the rubber separates from the swelling liquid.
Claim 11
Dependent Claim
24 words
A method as claimed in claim 7 in which the swelling liquid is tetrahydrofuran and the liquid miscible with the swelling liquid is water.
Claim 12
Dependent Claim
88 words
The method of claim 1 wherein said particles are further characterized by a tensile strength of about 9 MN/m 2 and a tear strength above 55 N/Std. when a rubber composition containing said particles as the sole rubber component is vulcanized by compounding 100 parts by weight of said particles with 2 parts of zinc oxide, 1 part of stearic acid, 1 part of Flectal H, 0.27 parts of cyclohexylbenzthiazylsulphenamide, 0.24 parts of diphenylguanidine and 0.53 parts of sulfur, and press molded to optimum cure at 150° C.
Claim 13
Dependent Claim
13 words
The method of claim 1 wherein said vulcanized rubber is whole tire crumb.
Claim 14
Dependent Claim
14 words
The method of claim 14 in which said vulcanized rubber is whole tire crumb.
Claim 15
Dependent Claim
22 words
The method of claim 1 wherein both the swelling and communiting are conducted at a temperature insufficient to damage the rubber structure.
Claim 16
Dependent Claim
11 words
The method of claim 12 wherein said temperature is ambient temperature.
Claim 17
Dependent Claim
18 words
The method of claim 1 wherein in step (2) the swollen rubber is comminuted in a disc mill.
Claim 18
Dependent Claim
17 words
The method of claim 14 wherein the discs of said disc mill are 46 grit carborundum stones.
Claim 19
Independent Claim
84 words
A method of converting vulcanized rubber into finely-divided vulcanized rubber consisting essentially of: 1. contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it, 2. comminuting the weakened material in a disc mill into particles of said vulcanized rubber, at least 90% of said particles having a particle size less than 20 microns, and said particles being further characterized by the property of separating out from an admixture with water, and 3. removing the liquid from said particles.
Claim 20
Independent Claim
84 words
A method of converting vulcanized rubber into finely-divided vulcanized rubber consisting essentially of: 1. contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it, 2. comminuting the weakened material in a disc mill into particles of said vulcanized rubber, at least 90% of said particles having a particle size less than 20 microns, and said particles being further characterized by the property of separating out from an admixture with water, and 3. removing the liquid from said particles.
Claim 21
Dependent Claim
14 words
A method as claimed in claim 16 which is carried out at ambient temperature.
Claim 22
Dependent Claim
13 words
The method of claim 16 wherein said vulcanized rubber is whole tire crumb.
Claim 23
Dependent Claim
38 words
The method of claim 16 wherein in step (3) a liquid which is miscible with the swelling liquid but not miscible with the rubber is added to the swelling liquid whereby the rubber separates from the swelling liquid.
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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) | 1980-09-19 | 1981-03-21 | 1981-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-19 | 1985-03-21 | 1985-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-19 | 1989-03-21 | 1989-09-20 | $7700.00 | Window Closed / Lapsed |