Patent US4335033A successfully refreshed from Google Patents.
US4335033A
Expired / Lapsed
US
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Eraser and process for its manufacture
Assignee: JS Staedtler GmbH and Co KG
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Filing: 1979-08-16
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Granted: 1982-06-15
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Expires: 1999-08-16
Abstract
Abstract An eraser based on polyvinyl chloride having particles of a crosslinked polymeric natural or synthetic rubber embedded in the polyvinyl chloride structure. Such erasers have high strength and good aging resistance. Additionally, conventional softeners in the eraser do not undergo significant migration and consequently, the eraser does not smudge. A process for manufacturing the eraser is also disclosed.
Inventors
- 👤 Werner Handl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:13
CPC Classifications
C; C08; C08L; C08L21/00; B; B43; B43L; B43L19/00; B43L19/0025; C08L27/00; C08L27/02; C08L27/04; C08L27/06; C08L7/00; C08L9/00; C08L9/02; C08L9/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
33 words
An eraser consisting essentially of polyvinyl chloride or polyvinyl chloride copolymer and particles of a crosslinked natural or synthetic rubber embedded in and distributed throughout the polyvinyl chloride or polyvinyl chloride copolymer structure.
Claim 2
Dependent Claim
33 words
An eraser consisting essentially of polyvinyl chloride or polyvinyl chloride copolymer and particles of a crosslinked natural or synthetic rubber embedded in and distributed throughout the polyvinyl chloride or polyvinyl chloride copolymer structure.
Claim 3
Dependent Claim
22 words
The eraser of claim 1 wherein the rubber is selected from the group consisting of natural rubber, butadiene styrene, and butadiene acrylonitrile.
Claim 4
Dependent Claim
20 words
The eraser of claim 1 wherein a polyvinyl chloride copolymer is used having a K value between 55 and 80.
Claim 5
Dependent Claim
17 words
The eraser of claim 1 wherein polyvinyl chloride is used having a K value of about 70.
Claim 6
Dependent Claim
37 words
An eraser consisting essentially of polyvinyl chloride or polyvinyl chloride copolymer and particles of a crosslinked natural or synthetic rubber embedded in and distributed throughout the polyvinyl chloride or polyvinyl chloride copolymer structure and softeners and dyes.
Claim 7
Dependent Claim
37 words
An eraser consisting essentially of polyvinyl chloride or polyvinyl chloride copolymer and particles of a crosslinked natural or synthetic rubber embedded in and distributed throughout the polyvinyl chloride or polyvinyl chloride copolymer structure and softeners and dyes.
Claim 8
Dependent Claim
53 words
An eraser consisting essentially of 30 to 60 parts by weight of polyvinyl chloride, 10 to 20 percent of a softener, 10 to 40 percent of a filler and 10 to 60 percent of a cross-linked natural or synthetic rubber in the form of particles embedded in and distributed throughout the polyvinyl chloride.
Claim 9
Dependent Claim
53 words
An eraser consisting essentially of 30 to 60 parts by weight of polyvinyl chloride, 10 to 20 percent of a softener, 10 to 40 percent of a filler and 10 to 60 percent of a cross-linked natural or synthetic rubber in the form of particles embedded in and distributed throughout the polyvinyl chloride.
References Cited (Backward Citations)
US2605247A
Cited
US3786011A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |