Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Reexamination Certificate
1999-12-28
2001-06-19
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C528S015000, C528S025000, C528S029000
Reexamination Certificate
active
06248915
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel, reactive silicon group-containing polyether oligomer and a method of producing the same. More particularly, it relates to a polyether oligomer containing a reactive silicon group within the molecule which is prepared by hydrosilylation of an unsaturated group-containing compound with a reactive silicon group-containing compound and to a method of producing the same.
PRIOR ART
Methods of producing reactive silicon group-containing polyether oligomers which comprise reacting an unsaturated group-containing polyether oligomer with a reactive silicon group-containing compound in the presence of a group VIII transition metal catalyst such as chloroplatinic acid have been disclosed (Japanese Kokoku Publications Sho-45-36319, Sho-46-12154, Sho-48-36960, Sho-58-41291, Sho-63-37820). However, in the hydrosilylation reaction between an unsaturated group and a reactive silicon-containing compound, a polyether oligomer having an allyl group as the unsaturated group undergoes a side reaction, namely the allyl group undergoes internal rearrangement to give a propenyl group, so that the reaction yield of the reactive silicon group relative to the unsaturated group has its limit.
Further, one of the main problems known to the people in the technical field where the hydrosilylation reaction is utilized is that, under the respective reaction conditions, the rate of reaction falls or the activity of the catalyst used in the reaction decreases during reaction, or the reaction stops. Thereby, in certain cases, not only the time required for the reaction is prolonged but also, the side reaction percentage relatively increases, leading to decreases in selectivity toward the desired hydrosilylation reaction. Even when the rate of reaction is increased by increasing the amount of an expensive metal catalyst, the amount of the catalyst remaining in the reaction product increases and this is unfavorable to the subsequent use in certain instances. (In the case of hydrosilylation of a high molecular polymer, for example, there is the problem that the catalyst-derived black powder is difficult to remove, hence the product becomes blackly muddy.) In case of deactivation of a platinum catalyst, as reported by A. Onopchenko et al. (J. Org. Chem., 52, 4118 (1987)) and L. N. Lewis et al. (J. Am. Chem. Soc., 112, 5998 (1990)) and in Japanese Kokai Publication Hei-5-213972, there is the method available which comprises using oxygen for reactivating the catalyst (Japanese Kokai Publication Hei-8-283339) . As for the addition of a substance capable of effectively accelerating the reaction, there have been proposed methods which comprise adding an acetylene alcohol (Japanese Kokai Publication Hei-8-231563), an unsaturated secondary or tertiary alcohol (Japanese Kokai Publication Hei-8-291181), a tertiary alcohol (Japanese Kokai Publication Hei-8-333373), an unsaturated ketone (Japanese Kokai Publication Hei-8-208838) or an ene-yne unsaturated compound (Japanese Kokai Publication Hei-9-25281), for instance.
The course of the hydrosilylation reaction is influenced by respective reactants and reaction conditions. In particular, the reactivity is apt to decrease when the unsaturated compound is a high-molecular polymer, when the concentration of the unsaturated group is low, when the viscosity of the reaction mixture is high, when an internal olefin is usedwhich is lower in hydrosilylation reactivity than the corresponding terminal olefin, or when the reactants and/or solvent contains a reaction inhibitor.
In such a system in which a decrease in reactivity is encountered, the side reaction percentage increases and the hydrosilylation percentage decreases as the reaction time is prolonged. The hydrosilylation reaction by which a hydrolyzable silyl group is introduced into a high-molecular polymer is important as practical means for synthesizing high-molecular polymers capable of being crosslinked by silanol condensation. As the hydrosilylation percentage of such high-molecular polymers decreases, the crosslink density decreases, hence the physical properties of the crosslinked products are affected, for example the strength decreases. For increasing the reaction yield, it is necessary to increase the amount of the expensive noble metal catalyst or silicon compound; this is unfavorable from the economical viewpoint. The methods of promoting the hydrosilylation reaction which have so far been contrived cannot always bring about a satisfactory solution to such a problem.
The present invention is to provide a novel method of promoting the hydrosilylation reaction more efficiently.
SUMMARY OF THE INVENTION
In an attempt to improve the reaction yield, relative to the unsaturated group, of the reactive silicon group, the present inventors made intensive investigations and it was surprisingly found that, when a polyether oligomer which contains an unsaturated group having a certain specific structure and can be produced with ease is used, a polyether oligomer containing a reactive silicon group with an markedly improved rate of reactive silicon group introduction relative to the unsaturated group, namely not less than 85% on average, can be obtained while the side reaction of the unsaturated group during the hydrosilylation reaction is suppressed, and that said hydrosilylation reaction is promoted in the presence of a sulfur compound. It is generally recognized that sulfur compounds inhibit the catalytic activity of metals, so that, in the prior art, the hydrosilylation conditions are selected so as to exclude sulfur compounds to the utmost. The use of a sulfur compound in accordance with the present invention, which is quite unexpected in view of the prior art general conception, is novel and has an important practical effect. It was further found that the polyether oligomer having a reactive silicon group introduced at not less than 85%, on average, of each molecular terminus can give cured products definitely superior in physical properties to those obtained from the polyether oligomers which have so far been used and have a reactive silicon group introduction percentage of at most 80%, on average, of each molecule terminus.
Thus, the first aspect of the present invention relates to a method of producing reactive silicon group-containing polyether oligomers which comprises reacting
(a) a polyether oligomer whose main chain is a polyether and which contains, in each molecule, at least one unsaturated group represented by the general formula (1):
H
2
C═C(R
1
)—R
2
—O— (1)
(in the formula, R
1
is a hydrocarbon group containing not more than 10 carbon atoms and R
2
is a divalent organic group containing 1 to 20 carbon atoms and one or more species selected from the group consisting of hydrogen, oxygen and nitrogen atoms as a constituent atom) or the general formula (2):
HC(R
1
)═CH—R
2
—O— (2)
(in the formula, R
1
is a hydrocarbon group containing not more than 10 carbon atoms and R
2
is a divalent organic group containing 1 to 20 carbon atoms and one or more species selected from the group consisting of hydrogen, oxygen and nitrogen atoms as a constituent atom) on a side chain or at a terminus
with (b) a reactive silicon group-containing compound in the presence of (c) a group VIII transition metal catalyst to introduce the reactive silicon group into said polyether oligomer (a),
wherein the reaction is carried out in the presence of (d) a sulfur compound.
In a preferred mode of embodiment, the present invention relates to the method of producing reactive silicon group-containing polyether oligomers,
wherein said reactive silicon group-containing compound is a compound represented by the general formula (3):
H—(Si(R
3
2−b
)(X
b
)O)
m
Si(R
4
3−a
)Xa (3)
(in the formula, R
3
and R
4
are the same or different and each independently represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy gr
Ito Hiroshi
Iwakiri Hiroshi
Jyono Hideharu
Kawakubo Fumio
Odaka Hidetoshi
Connolly Bove Lodge & Hutz
Kaneka Corporation
Shaver Paul F.
LandOfFree
Method of producing reactive silicon group-containing... 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 of producing reactive silicon group-containing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing reactive silicon group-containing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509366