US4459247A
Expired / Lapsed
US
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Method for producing earplugs of foamed plastic
Assignee: Rehau Plastiks GmbH
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Filing: 1982-03-02
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Granted: 1984-07-10
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Expires: 2002-03-02
Abstract
Abstract The invention relates to an earplug, produced with the use of a polysiloxane which is made foamable and cross-linkable by the use of expanding and cross-linking agents. The method for producing such an earplug comprises preshaping the polysiloxane together with the additives, then finally shaping the earplug in the foaming process and then tempering the finally shaped product.
Inventors
- 👤 Karl Rothemund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:24
CPC Classifications
A; A61; A61F; A61F11/00; A61F11/06; A61F11/08; A61F11/10; B; B29; B29C; B29C44/00; B29C44/02; B29C44/04; B29C44/0407; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/18
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
57 words
Method for producing an earplug of foamed plastic, comprising initially mixing a polysiloxane with at least one additive which is an expanding agent and preshaping the mixture, thereafter heating the mixture to foam the mixture and form its final shape, cross-linking the finally shaped product, and finally subjecting the finally shaped product to a final tempering process.
Claim 2
Dependent Claim
57 words
Method for producing an earplug of foamed plastic, comprising initially mixing a polysiloxane with at least one additive which is an expanding agent and preshaping the mixture, thereafter heating the mixture to foam the mixture and form its final shape, cross-linking the finally shaped product, and finally subjecting the finally shaped product to a final tempering process.
Claim 3
Dependent Claim
20 words
Method according to claim 1, wherein the preshaped product is subdivided into individual sections before the foaming and cross-linking processes.
Claim 4
Dependent Claim
25 words
Method according to claim 2, wherein the individual sections are additionally deformed by the use of a compression pressure and are subsequently foamed and cross-linked.
Claim 5
Dependent Claim
18 words
Method according to claim 1, wherein the product is subdivided into individual sections after being foamed and cross-linked.
Claim 6
Dependent Claim
18 words
Method according to claim 1, wherein the heat for the foaming simultaneously constitutes heat which effects the cross-linking.
Claim 7
Dependent Claim
24 words
Method according to claim 1, wherein after the foaming process is performed with the use of heat, and the finally foamed product is cross-linked.
Claim 8
Dependent Claim
14 words
Method according to claim 1, wherein the cross-linking is effected by high energy radiation.
Claim 9
Dependent Claim
17 words
Method according to claim 1, wherein the foaming heat and the cross-linking heat are below 250° C.
Claim 10
Dependent Claim
19 words
Method according to claim 1, wherein the tempering process takes place at a temperature of at least 140° C.
Claim 11
Dependent Claim
20 words
Method according to claim 1, wherein the foaming heat and the cross-linking heat are between 90° C. and 160° C.
Claim 12
Dependent Claim
20 words
Method according to claim 1, wherein the additives comprise an expanding agent, and the tempering process removes expanding agent residues.
Claim 13
Dependent Claim
20 words
Method according to claim 11, wherein the additives comprise a cross-linking agent, and the tempering process removes cross-linking agent residues.
Claim 14
Dependent Claim
20 words
Method according to claim 1, wherein the additives comprise at least one expanding agent and at least one cross-linking agent.
Claim 15
Dependent Claim
32 words
Method according to claim 1, wherein the expanding agent is selected from azodicarbonamide, benzene sulfohydrazide, diphenyl sulfone-3,3 disulfohydrazide, diphenylene oxide-4,4 disulfohydrazide, trihydrazionotriazine, p-toulene sulfonyl semicarbazide, 5-phenyltetrazole, isatoic acid anhydride, and sodium bicarbonate.
Claim 16
Dependent Claim
13 words
The process according to claim 1, wherein the additives comprise a cross-linking agent.
Claim 17
Dependent Claim
23 words
Method according to claim 1, wherein the cross-linking agent is selected from benzoyl peroxide, chlorobenzoyl peroxide, t-butyl perbenzoate, dicumyl peroxide and di-t-butyl peroxide.
Claim 18
Dependent Claim
10 words
Method according to claim 1, wherein the additives include fillers.
Claim 19
Dependent Claim
24 words
Method according to claim 17, wherein the fillers include oxidic or salt-like compounds of calcium, barium, magnesium, aluminum, silicon, titanium, iron, zinc or zirconium.
Claim 20
Dependent Claim
20 words
Method according to claim 1, wherein the polysiloxane is represented by the formula: ##STR2## where R is an organic radical.
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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) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |