US3957495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid writing material
Assignee: Pilot Corp
•
Filing: 1974-05-24
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Granted: 1976-05-18
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Expires: 1994-05-24
Abstract
Abstract A writing material in solid form containing a solid vehicle in which is dispersed a non-volatile oily solvent containing electron a substantially colorless donative chromogenic compound which develops color upon contact with an electron accepting substance, more than 50 % by weight of the solid vehicle being an ester of a higher (hydroxy) fatty acid or a mixture comprising an ester of a higher (hydroxy) fatty acid and a microcrystalline wax, and the non-volatile oily solvent being contained in the writing material in a range of from 10 to 50 % by weight of the entire writing material.
Inventors
- 👤 Takeshi Teranishi
- 👤 Tatuo Ishiki
- 👤 Kunio Kosaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:21
CPC Classifications
C; C09; C09D; C09D13/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
In a writing instrument containing a writing material in solid form made by dispersing, in a solid vehicle, a non-volatile oily solvent containing a substantially colorless electron donative chromogenic compound which develops color upon contact with an electron accepting substance on a writing surface, the improvement wherein more than 50% by weight of the solid vehicle is a mixture of an ester of a higher (hydroxy) fatty acid and a microscrystalline wax, and the non-volatile oily solvent is contained in the writing material in a quantity of from 10% to 50% by weight of the writing material.
Claim 2
Dependent Claim
97 words
In a writing instrument containing a writing material in solid form made by dispersing, in a solid vehicle, a non-volatile oily solvent containing a substantially colorless electron donative chromogenic compound which develops color upon contact with an electron accepting substance on a writing surface, the improvement wherein more than 50% by weight of the solid vehicle is a mixture of an ester of a higher (hydroxy) fatty acid and a microscrystalline wax, and the non-volatile oily solvent is contained in the writing material in a quantity of from 10% to 50% by weight of the writing material.
Claim 3
Dependent Claim
23 words
A writing instrument as set forth in claim 1 wherein the ester of the higher (hydroxy) fatty acid is glycerol tri (hydroxy) stearate.
Claim 4
Dependent Claim
28 words
A writing instrument as set forth in claim 1 wherein a higher normal saturated alcohol having from 14 to 22 carbon atoms is added to the solid vehicle.
Claim 5
Dependent Claim
15 words
A writing instrument as set forth in claim 3 wherein the alcohol is stearyl alcohol.
Claim 6
Dependent Claim
50 words
A writing instrument as set forth in claim 1 wherein the non-volatile oily solvent is selected from the group consisting of methyl acetyl ricinolate, dibutyl phthalate, dioctyl phthalate, phthalyl butyl glycolate and aromatic hydrocarbons having a molecular weight of from 150 to 300 and a boiling point higher than 500°F.
Claim 7
Dependent Claim
15 words
A writing instrument as set forth in claim 1 in the form of a crayon.
Claim 8
Dependent Claim
36 words
A writing instrument a set forth in claim 1 wherein the microcrystalline wax is a residual or tank bottom wax having a melting point ranging from 145° to 200°F and from 36 to 70 carbon atoms.
References Cited (Backward Citations)
US2748024A
Cited
US2755420A
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US3079253A
Cited
US3484264A
Cited
US3672842A
Cited
US3769045A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |