US4350787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermoplastic eraser
Assignee: JS Staedtler GmbH and Co KG
•
Filing: 1981-02-10
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Granted: 1982-09-21
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Expires: 2001-02-10
Abstract
Abstract An eraser composed of conventional fillers and additives and, in addition, a binder of a styrene-isoprene-styrene block copolymer. The eraser composition does not require any aftertreatment, e.g., vulcanization, and can be fabricated into erasers utilizing single equipment.
Inventors
- 👤 Gunter Kimpel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:14
CPC Classifications
C; C08; C08L; C08L53/00; C08L53/02; B; B43; B43L; B43L19/00; B43L19/0025; C08K; C08K3/00; C08K3/01; C08K3/013
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
47 words
In an eraser composition composed of fillers, a thermoplastic synthetic rubber as the binder, and conventional additives, the improvement which comprises the binder being a styrene-isoprene-styrene block copolymer having a styrene portion of 10 to 20% by weight and further containing 0.5 to 5% by weight polynorbornene.
Claim 2
Dependent Claim
47 words
In an eraser composition composed of fillers, a thermoplastic synthetic rubber as the binder, and conventional additives, the improvement which comprises the binder being a styrene-isoprene-styrene block copolymer having a styrene portion of 10 to 20% by weight and further containing 0.5 to 5% by weight polynorbornene.
Claim 3
Dependent Claim
17 words
The eraser of claim 1 which further contains 1 to 25% by weight stereospecific, liquid, low-viscosity polybutadiene.
Claim 4
Dependent Claim
25 words
The eraser of claim 2 wherein the low-viscosity polybutadiene has a molecular weight of 1,000 to 4,000 and a viscosity of 700 to 3,000 mPa.s.
Claim 5
Dependent Claim
35 words
The eraser of claim claim 1, 2, or 3 wherein the low-viscosity polybutadiene has 70 to 80% 1,4 cis double bonds, 15 to 30% 1,4 trans double bonds and 1 to 5% vinyl double bonds.
Claim 6
Dependent Claim
16 words
The eraser of claim 1, 2, or 3 which contains 5 to 20% by weight factice.
Claim 7
Dependent Claim
16 words
The eraser of claim 1, 2, or 3 which contains 5 to 20% by weight factice.
Claim 8
Dependent Claim
17 words
The eraser of claim 1, 2, or 3 which contains 5 to 20% by weight naphthenic oils.
Claim 9
Dependent Claim
17 words
The eraser of claim 1, 2, or 3 which contains 1 to 20% by weight paraffinic oil.
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) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |