Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2000-11-01
2002-04-23
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C556S450000, C556S453000, C556S455000, C556S479000, C528S015000, C528S025000
Reexamination Certificate
active
06376635
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an oligosiloxane and more particularly to an oligosiloxane containing both silicon-bonded alkoxy and monovalent hydrocarbyl groups, wherein each hydrocarbyl group is free of aliphatic unsaturation and has at least 11 carbon atoms. This invention also relates to a method of preparing an alkoxy-functional oligosiloxane.
BACKGROUND OF THE INVENTION
Silicon-bonded alkoxy-functional oligosiloxanes are disclosed in Japanese Laid Open (Kokai or Unexamined) Patent Application Numbers Hei 3-197486 (197,486/1991), Hei 4-7305 (7,305/1992), and Hei 5-70514 (70,514/1993). However, none of the references teach an alkoxy-functional oligosiloxane containing a monovalent hydrocarbyl group free of aliphatic unsaturation and having at least 11 carbon atoms.
Methods for preparing silicon-bonded alkoxy-functional oligosiloxanes are known. For example, Japanese Laid Open (Kokai or Unexamined) Patent Application Number Hei 3-197486 (197,486/1991) teaches the reaction of silanol-functional oligosiloxane or silane with silicon-bonded alkoxy-functional silane in the presence of the hydroxide or chloride of an alkali metal or alkaline-earth metal or in the presence of a basic metal salt. In addition, the reaction of silanol-functional silane and silicon-bonded alkoxy-functional silane in the presence of an amine compound is taught in Japanese Laid Open (Kokai or Unexamined) Patent Application Numbers Hei 4-7305 (7,305/1992) and Hei 5-70514 (70,514/1993). These methods, however, suffer from impaired yields of the desired oligosiloxane because they require the use of an unstable silanol-functional oligosiloxane or silane and because the silanol group in the starting oligosiloxane or silane undergoes intermolecular condensation with other silanol in the same reactant.
SUMMARY OF THE INVENTION
One object of the present invention is to provide novel oligosiloxanes containing both silicon-bonded alkoxy and monovalent hydrocarbyl groups, wherein each hydrocarbyl group is free of aliphatic unsaturation and has at least 11 carbon atoms. Another object of this invention is to provide a highly efficient method for synthesizing an alkoxy-functional oligosiloxane.
The present invention is directed to an oligosiloxane having the formula:
(R
1
O)
a
Si(OSiR
2
2
R
3
)
4−a
wherein R
1
is alkyl; each R
2
is independently selected from C
1
to C
10
monovalent hydrocarbyl free of aliphatic unsaturation; R
3
is monovalent hydrocarbyl free of aliphatic unsaturation and having at least 11 carbon atoms; and a is 1, 2, or 3.
This invention is also directed to a method of preparing an oligosiloxane having the formula:
(R
1
O)
a
Si(OSiR
2
2
R
3
)
4−a
comprising reacting an oligosiloxane having the formula:
(R
1
O)
a
Si(OSiR
2
2
H)
4−a
with a hydrocarbon containing 1 aliphatic double bond per molecule in the presence of a hydrosilylation catalyst, wherein R
1
is alkyl; each R
2
is independently selected from C
1
to C
10
monovalent hydrocarbyl free of aliphatic unsaturation; R
3
is monovalent hydrocarbyl free of aliphatic unsaturation and having at least 2 carbon atoms; and a is 1, 2, or 3.
The oligosiloxanes synthesized as described above are useful as surface treatment agents for inorganic fillers and as reactive oligosiloxanes capable of reacting with silanol-functional organopolysiloxanes and hydroxyl-functional organic resins. The method of the present invention affords silicon-bonded alkoxy-functional oligosiloxanes at high efficiencies.
DETAILED DESCRIPTION OF THE INVENTION
An oligosiloxane according to the present invention has the formula:
(R
1
O)
a
Si(OSiR
2
2
R
3
)
4−a
wherein R
1
is alkyl; each R
2
is independently selected from C
1
to C
10
monovalent hydrocarbyl free of aliphatic unsaturation; R
3
is monovalent hydrocarbyl free of aliphatic unsaturation and having at least 11 carbon atoms; and a is 1, 2, or 3.
Examples of alkyl groups represented by R
1
include, but are not limited to, straight-chain alkyl such as methyl, ethyl, propyl, butyl, hexyl, and decyl; branched alkyl such as isopropyl, tert-butyl, and isobutyl; and cyclic alkyl such as cyclohexyl. R
1
preferably is C
1
to C
4
alkyl and more preferably is methyl or ethyl. R
2
is exemplified by straight-chain alkyl such as methyl, ethyl, propyl, butyl, hexyl, and decyl; branched alkyl such as isopropyl, tert-butyl, and isobutyl; cyclic alkyl such as cyclohexyl; aryl such as phenyl, tolyl, and xylyl; and aralkyl such as benzyl and phenethyl. R
2
is preferably C
1
to C
4
alkyl and more preferably is methyl or ethyl. R
3
is exemplified by straight-chain alkyl such as undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; branched alkyl such as 2-methylundecyl and 1-hexylheptyl; cyclic alkyl such as cyclododecyl; and aralkyl such as 2-(2,4,6-trimethylphenyl)propyl. R
3
is preferably straight-chain alkyl and more preferably is C
11
to C
20
straight-chain alkyl. The subscript a in the general formula under consideration can be 1, 2, or 3 and preferably is 3.
The oligosiloxanes of this invention are exemplified by the following compounds:
The oligosiloxanes described above, because they contain silicon-bonded alkoxy and monovalent hydrocarbyl groups, wherein each hydrocarbyl group is free of aliphatic unsaturation and has at least 11 carbon atoms, are useful as surface treatment agents for inorganic fillers and as reactive oligosiloxanes capable of reacting with silanol-functional organopolysiloxanes and hydroxyl-functional organic resins.
A method according to the present invention of preparing an oligosiloxane having the formula:
(R
1
O)
a
Si(OSiR
2
2
R
3
)
4−a
comprises reacting an oligosiloxane (A) having the formula:
(R
1
O)
a
Si(OSiR
2
2
R
3
)
4−a
with a hydrocarbon (B) containing 1 aliphatic double bond per molecule in the presence of a hydrosilylation catalyst (C), wherein R
1
, R
2
, and subscript a are as defined and exemplified above, including the preferred embodiments thereof; R
3
is monovalent hydrocarbyl free of aliphatic unsaturation and having at least 2 carbon atoms. Preferably, the monovalent hydrocarbyl groups represented by R
3
have at least 11 carbon atoms.
Examples of hydrocarbyl groups represented by R
3
include, but are not limited to, straight-chain aliphatic hydrocarbyl such as ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, and nonadecyl; branched aliphatic hydrocarbyl such as 1-methylbutyl, 1-ethylpropyl, 1-ethylbutyl, 2-methylundecyl, and 1,1-dimethyldecyl; cyclic aliphatic hydrocarbyl such as cyclododecyl; and aromatic hydrocarbyl such as 2-(2,4,6-trimethylphenyl)propyl. R
3
is preferably straight-chain aliphatic hydrocarbyl (i.e., alkyl), more preferably is C
2
to C
20
straight-chain aliphatic hydrocarbyl, and most preferably is C
11
to C
20
straight-chain aliphatic hydrocarbyl.
The oligosiloxane (A) can itself be synthesized, for example, by the reaction of tetraalkoxysilane having the general formula Si(OR
1
)
4
, wherein R
1
is alkyl, with a disiloxane having the general formula R
2
2
HSiOSiR
2
2
H, wherein each R
2
is independently selected from C
11
to C
10
monovalent hydrocarbon groups free of aliphatic unsaturation, in the presence of a strong acid and a carboxylic acid.
The oligosiloxane (A) is exemplified by trialkoxysiloxydialkylsilanes such as trimethoxysiloxydimethylsilane, triethoxysiloxydimethylsilane, and tripropoxysiloxydimethylsilane; bis(dialkylsiloxy)dialkoxysilanes such as bis(dimethylsiloxy)dimethoxysilane, bis(dimethylsiloxy)diethoxysilane, bis(dimethylsiloxy)dipropoxysilane, and bis(dimethylsiloxy)dibutoxysilane; and tris(dialkylsiloxy)alkoxysilanes such as tris(dimethylsiloxy)methoxysilane, tris(dimethylsiloxy)ethoxysilane, tris(dimethylsiloxy)propoxysilane, and tris(dimethylsiloxy)butoxysilane.
A characteristic feature of the hydrocarbon (B) is that it contains 1 aliphatic double bond in each molecule. The molecular structure of
Amako Masaaki
Enami Hiroji
Okawa Tadashi
Onishi Masayuki
Brown Catherine
Dow Corning Toray Silicon Co., Ltd.
Milco Larry
Zimmer Marc S.
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