Color-changing marking composition system
US5460647A · kind A · utility
33Cited by
90References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1995 |
| Grant date | Oct 24, 1995 |
| Priority date | — |
| Expiry date | Feb 10, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D13/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A color-changing marking composition system, suitable for use in the form of crayons and pencils, comprising a first marking composition comprising wax, a Leuco dye capable of changing color upon contact with a color change-inducing compound, and a solvent capable of solubilizing the dye; and a second marking composition comprising wax and a color change-inducing compound, which is capable of inducing a color change in a Leuco dye with which it is brought in contact.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.