Process for the preparation of polyurethane microcapsules containing monocrotophos
US5962003A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1998 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Mar 30, 2018 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01N57/12
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a process for the preparation of polyurethane microcapsules containing monocrotophos, which comprises of preparing a solution of diol or polyol having a molecular weight in the range of 200-2000, crosslinker, monocrotophos and a catalyst selected from amino or organometallic compounds; dispersing this solution into a dilute solution of stabilizer which consists of a block copolymer having the general formula A!.sub.n -B!.sub.m where A and B are chemically and compositionally dissimilar segments where n and m segments are in between 30-115 and 10-60 units respectively, such that the sum of n and m does not exceed 175 units, in an aliphatic hydrocarbon; adding an isocyanate dropwise to this dispersion; agitating the mixture at 1000-1400 revolutions per minute for the first 6-8 hours and then at 500-800 revolutions per minute for an additional period of 14-18 hours at a temperature between 30.degree. to 40.degree. C. to permit the formation of polyurethane microcapsules; heating the dispersion for an additional period of 1-2 hours at a temperature not exceeding 50.degree. C.; filtering the microcapsules; washing the microcapsules with lower aliphatic h…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.