Coating processes – Particles – flakes – or granules coated or encapsulated – Inorganic base
Patent
1990-06-06
1991-05-07
Beck, Shrive
Coating processes
Particles, flakes, or granules coated or encapsulated
Inorganic base
427215, 428405, B05D 700
Patent
active
050135856
ABSTRACT:
A method for the preparation of a stable silica organosol in a hydrophobic organic solvent is proposed. The method comprises (a) hydrolyzing a tetraalkoxy silane, e.g. tetraethoxy silane, in an alcoholic medium in the presence of a limited amount of water and ammonia as a catalyst under controlled conditions so as to produce a silica alcosol in which the silica particles satisfy the requirements that the alkoxy groups and silanolic hydroxy groups are bonded to the silicon atoms on the surface in densities of at least 3.5 .mu. moles/m.sup.2 and not exceeding 2 .mu. mmoles/m.sup.2, respectively, and the specific surface area S given in m.sup.2 /g and the average particle diameter D given in nm of the silica particles satisfy the relationship of S.times.D.gtoreq.5000, D being 1 nm or larger, and (b) admixing the alcosol of silica particles with an organosilicon compound selected from the group consisting of the compounds represented by the general formula R.sub.4-n SiX.sub.n, (R.sub.3 Si).sub.2 NH, or YO--(--SiR.sub.2 --O--).sub.m --Y, in which each R is, independently from the others, a hydrogen atom or a monovalent hydrocarbon group, X is a hydroxy group or an alkoxy group, Y is a hydrogen atom or an alkyl group, n is 1, 2 or 3 and m is a positive integer not exceeding 20, in an amount, for example, in the range from 0.01 to 10 moles per mole of the silica particles under agitation of the mixture to effect a reaction for the modification of the surface of the silica particles followed by replacement of the alcoholic medium with a desired organic solvent.
REFERENCES:
patent: 2829981 (1958-04-01), Shapiro
patent: 2993809 (1961-07-01), Bueche et al.
patent: 4013574 (1977-03-01), Leikhim et al.
patent: 4015031 (1977-03-01), Reinhardt et al.
patent: 4030940 (1977-06-01), Chviro et al.
patent: 4151154 (1979-04-01), Berger
patent: 4724167 (1988-02-01), Evans et al.
patent: 4756971 (1988-07-01), Virtanen et al.
patent: 4844980 (1989-07-01), Gruning et al.
patent: 4847159 (1989-07-01), Glajch et al.
patent: 4895914 (1990-01-01), Saitoh et al.
Ogihara Tsutomu
Shimizu Takaaki
Takita Masatoshi
Bashore Alain
Beck Shrive
Shin-Etsu Chemical Co. , Ltd.
LandOfFree
Method for the preparation of surface-modified silica particles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the preparation of surface-modified silica particles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the preparation of surface-modified silica particles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-938740