US4017451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pencil lead and manufacturing method of the same
Assignee: Oriental Sangyo Co Ltd
•
Filing: 1975-06-16
•
Granted: 1977-04-12
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Expires: 1995-06-16
Abstract
Abstract A pencil lead comprises an extrudate of a kneaded blend of a coloring material and a novolak resin or a derivative thereof.
Inventors
- 👤 Nobuhiro Ishida
- 👤 Kazuyuki Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:26
CPC Classifications
C; C08; C08L; C08L63/00; C08L63/04; C08K; C08K3/00; C08K3/02; C08K3/04; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
23 words
A pencil lead comprising an extrudate of a kneaded blend of a coloring material and a novolak resin or a novolak epoxy resin.
Claim 2
Dependent Claim
23 words
A pencil lead comprising an extrudate of a kneaded blend of a coloring material and a novolak resin or a novolak epoxy resin.
Claim 3
Dependent Claim
45 words
The pencil lead of claim 1 wherein the kneaded blend comprises (1) 50 to 80% by weight of a coloring material, (2) 5 to 50% by weight of said novolak or novolak epoxy resin and (3) 5 to 20% by weight of a lubricant ingredient.
Claim 4
Dependent Claim
40 words
The pencil lead of claim 2 wherein the kneaded blend additionally comprises 2 to 50% by weight of a thermoplastic resin selected from the group consisting of styrene resins, vinyl chloride resins, vinylacetate resins and bisphenol epichlorohydrine derived epoxy resin.
Claim 5
Dependent Claim
73 words
The pencil lead of claim 2 wherein the kneaded blend comprises (1) 50 to 80% by weight of a coloring material, (2) 5 to 30% by weight of said novolak or novolak epoxy resin, (3) 5 to 15% by weight of a lubricant ingredient and (4) 2 to 15% by weight of a thermoplastic resin selected from the group consisting of styrene resins, vinylchloride resins, vinylacetate resin and bisphenol epichlorohydrine derived epoxy resin.
Claim 6
Dependent Claim
18 words
The pencil lead of claim 1 wherein said novolak or novolak epoxy resin is in the solid state.
Claim 7
Dependent Claim
15 words
The pencil lead of claim 1 wherein said coloring material is natural or artificial graphite.
Claim 8
Dependent Claim
47 words
A process for manufacturing a pencil lead characterized by blending a coloring material with a novolak resin or derivative thereof and kneading, and extruding the resulting blend under a die temperature of 100° to 150° C and an extrusion pressure of 200 to 3,000 kg/cm 2 .
Claim 9
Dependent Claim
47 words
A process for manufacturing a pencil lead characterized by blending a coloring material with a novolak resin or derivative thereof and kneading, and extruding the resulting blend under a die temperature of 100° to 150° C and an extrusion pressure of 200 to 3,000 kg/cm 2 .
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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |