Patent US3953389A successfully refreshed from Google Patents.
US3953389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of powdered rubbers
Assignee: BP Chemicals Ltd
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Filing: 1975-05-28
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Granted: 1976-04-27
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Expires: 1995-05-28
Abstract
Abstract Process for the preparation of a free-flowing powdered rubber by treating a rubber with an aqueous dispersion of an anti-tack agent and suspending the rubber in powdered form in a stream of gas (e.g. air), removing at least part of the water and subsequently treating the powdered rubber with a dusting material.
Inventors
- 👤 Gilbert John Holliday
- 👤 John Norris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:47
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J3/124; C08J2321/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
86 words
A process for the preparation of a free-flowing powdered rubber which comprises reducing a rubber to a fine powder by air attrition in which coarse ground rubbery material is conveyed through a comminution zone by a current of air, adding an aqueous dispersion of an anti-tack agent to the fine powdered rubbery material and suspending the rubbery material in a powdered form in a stream of a gas, removing at least part of the water, and subsequently treating the powdered rubbery material with a dusting powder.
Claim 2
Dependent Claim
86 words
A process for the preparation of a free-flowing powdered rubber which comprises reducing a rubber to a fine powder by air attrition in which coarse ground rubbery material is conveyed through a comminution zone by a current of air, adding an aqueous dispersion of an anti-tack agent to the fine powdered rubbery material and suspending the rubbery material in a powdered form in a stream of a gas, removing at least part of the water, and subsequently treating the powdered rubbery material with a dusting powder.
Claim 3
Dependent Claim
28 words
A process as claimed in claim 1 wherein the aqueous dispersion of anti-tack agent is added to the powdered rubbery material suspended in a stream of a gas.
Claim 4
Dependent Claim
12 words
A process as claimed in claim 1 wherein the gas is air.
Claim 5
Dependent Claim
20 words
A process as claimed in claim 1 wherein the rubbery material is a copolymer of butadiene with styrene or acrylonitrile.
Claim 6
Dependent Claim
23 words
A process as claimed in claim 1 wherein the air supply to the air attrition mill is at a temperature below ambient temperature.
Claim 7
Dependent Claim
23 words
A process as claimed in any claim 1 wherein the rubbery material is cooled to a temperature below ambient temperatures before being powdered.
Claim 8
Dependent Claim
25 words
A process as claimed in claim 1 wherein the anti-tack agent is a sodium or potassium salt of a long chain, soap forming, fatty acid.
Claim 9
Dependent Claim
17 words
A process as claimed in claim 7 wherein the anti-tack agent further contains a particulate mineral filler.
Claim 10
Dependent Claim
29 words
A process as claimed in claim 1 from 1 gallon to 10 gallons of a 25% aqueous suspension of the anti-tack agent are added per ton of rubbery material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-27 | 1979-10-27 | 1980-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-27 | 1983-10-27 | 1984-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-27 | 1987-10-27 | 1988-04-27 | $7700.00 | Window Closed / Lapsed |