Hydrogen-functional silylated polymethylsilsesquioxane
US5939500A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 1998 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Feb 23, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/20
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A hydrogen-functional silylated polymethylsilsesquioxane that contains no more than 0.12 residual silanol per Si atom and is obtained by silylating the silanol in starting polymethylsilsesquioxane. The starting polymethylsilsesquioxane has a predetermined number average molecular weight, Mn, from 380 to 2,000 and is represented by the general formula EQU (CH.sub.3 SiO.sub.3/2).sub.n (CH.sub.3 Si(OH)O.sub.2/2).sub.m wherein m and n are positive numbers that provide the predetermined Mn, with the proviso that the value of m/(m+n) is less than or equal to 0.152/(Mn.times.10.sup.-3)+0.10 and greater than or equal to 0.034/(Mn.times.10.sup.-3). The hydrogen-functional silylated polymethylsilsesquioxane has the formula EQU (CH.sub.3 SiO.sub.3/2).sub.n (CH.sub.3 Si(OH)O.sub.2/2).sub.m-k (CH.sub.3 Si(OSiR.sup.1 R.sup.2 R.sup.3)O.sub.2/2).sub.k wherein k is a positive number smaller than m, (m-k/(m+n) is less than or equal to 0.12, and R.sup.1, R.sup.2, and R.sup.3 are each selected from substituted and unsubstituted monovalent hydrocarbon groups with the proviso that at least 1 of said R.sup.1, R.sup.2, and R.sup.3 is hydrogen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.