US4244841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for recycling rubber and recycled rubber product
Assignee: FRANKLAND ENTERPRISES Inc A CORP OF FL
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Filing: 1980-03-24
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Granted: 1981-01-13
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Expires: 2000-03-24
Abstract
Abstract A unique method for recycling rubber scrap to yield a final product of at least about one inch in thickness characterized by the absence of the use of alkalis, acids or organic solvents in the steps of the process. Finely ground dry rubber scrap is intimately mixed with a cure mix comprising about nine parts, by weight, dry sulfur and not more than about one part, by weight, zinc stearate. The resulting dry cure mix and dry rubber scrap mixture is placed into a mold and cured in a steam autoclave for about 1.25-4 hours at a temperature of about 325° F., preferably, while maintaining a steam pressure within the autoclave of about 125 psi, preferably. Actual curing time is determined by the thickness of the final product. The final recycled rubber product is also claimed.
Inventors
- 👤 W. Howard Frankland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:27
CPC Classifications
C; C08; C08J; C08J11/00; C08J11/04; B; B29; B29B; B29B17/00; B29B17/0026; B29B17/0042; B29C; B29C43/00; B29C43/003; B29K; B29K2021/00; B29K2105/00; B29K2105/25; B29K2105/251; B29K2105/26; C08J2321/00; Y; Y02; Y02P; Y02P20/00; Y02P20/141; Y02P20/143; Y02W; Y02W30/00; Y02W30/50; Y02W30/62
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
168 words
A method for recycling rubber scrap to yield a final product of at least about one inch in thickness, said method comprising the steps of: a. preparing a cure mix by intimately mixing together about nine parts, by weight, sulfur and not more than about one part, by weight, zinc stearate; b. admixing about 3-8 parts, by weight, of said cure mix with about 100 parts, by weight, dry ground rubber; c. placing the resulting cure mix and ground rubber mixture into a mold; d. closing said mold and compressing said mixture to a thickness of at least about one inch; e. placing said closed mold into a steam autoclave; f. curing said mixture within said mold in said steam autoclave for about 1.25-4 hours at a temperature of about 310° F. to less than about 350° F. while maintaining a steam pressure within said autoclave of about 77-130 psi; g. removing said mold from said autoclave; and h. removing the final recycled rubber product from said mold.
Claim 2
Independent Claim
168 words
A method for recycling rubber scrap to yield a final product of at least about one inch in thickness, said method comprising the steps of: a. preparing a cure mix by intimately mixing together about nine parts, by weight, sulfur and not more than about one part, by weight, zinc stearate; b. admixing about 3-8 parts, by weight, of said cure mix with about 100 parts, by weight, dry ground rubber; c. placing the resulting cure mix and ground rubber mixture into a mold; d. closing said mold and compressing said mixture to a thickness of at least about one inch; e. placing said closed mold into a steam autoclave; f. curing said mixture within said mold in said steam autoclave for about 1.25-4 hours at a temperature of about 310° F. to less than about 350° F. while maintaining a steam pressure within said autoclave of about 77-130 psi; g. removing said mold from said autoclave; and h. removing the final recycled rubber product from said mold.
Claim 3
Dependent Claim
18 words
A method as in claim 1 wherein said sulfur is sized to pass through a 300 mesh screen.
Claim 4
Dependent Claim
34 words
A method as in claim 1 comprising admixing about 3 parts, by weight, of said cure mix to said ground rubber whereby said final product will exhibit a hardness of about 55-65 Shore A.
Claim 5
Dependent Claim
34 words
A method as in claim 1 comprising admixing about 6 parts by weight, of said cure mix to said ground rubber whereby said final product will exhibit a hardness of about 75-80 Shore A.
Claim 6
Dependent Claim
34 words
A method as in claim 1 comprising admixing about 8 parts, by weight, of said cure mix to said ground rubber whereby said final product will exhibit a hardness of about 90 Shore A.
Claim 7
Dependent Claim
15 words
A method as in claim 1 wherein said ground rubber comprises tire tread stock buffings.
Claim 8
Dependent Claim
29 words
A method as in claim 1 wherein said ground rubber comprises tire tread stock buffings and no more than about 25%, by weight, of said final reclaimed rubber product.
Claim 9
Dependent Claim
36 words
A method as in claim 1 wherein said mixture is compressed into said mold at about 400 psi to the predetermined thickness of said final product prior to placing said closed mold into said steam autoclave.
Claim 10
Dependent Claim
29 words
A method as in claim 1 wherein said curing is conducted at a temperature of about 344° F. while maintaining said pressure within said autoclave at about 125 psi.
Claim 11
Dependent Claim
22 words
A method as in claim 1 further comprising the step of cooling said mold prior to removing said final recycled rubber product.
Claim 12
Dependent Claim
16 words
A method as in claim 10 wherein said cooling comprises passing a fluid across said mold.
Claim 13
Dependent Claim
15 words
A method as in claim 10 wherein said cooling comprises spraying water onto said mold.
Claim 14
Dependent Claim
16 words
A method as in claim 10 wherein said cooling comprises spraying a gas onto said mold.
Claim 15
Dependent Claim
12 words
A method as in claim 13 wherein said cooling gas comprises air.
Claim 16
Dependent Claim
85 words
A recycled rubber product of at least about one inch in thickness formed by curing a mixture consisting essentially of 100 parts, by weight, dry tire tread stock buffings and 3-8 parts, by weight, dry cure mix wherein said cure mix comprises about nine parts, by weight, sulfur and not more than about one part, by weight, zinc stearate, in a steam autoclave for about 1.25-4 hours at a temperature of about 344° while maintaining a steam pressure within said autoclave of about 125 psi.
Claim 17
Dependent Claim
85 words
A recycled rubber product of at least about one inch in thickness formed by curing a mixture consisting essentially of 100 parts, by weight, dry tire tread stock buffings and 3-8 parts, by weight, dry cure mix wherein said cure mix comprises about nine parts, by weight, sulfur and not more than about one part, by weight, zinc stearate, in a steam autoclave for about 1.25-4 hours at a temperature of about 344° while maintaining a steam pressure within said autoclave of about 125 psi.
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) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |