Multiphase formulations of organosilicon compounds

Details Multiphase formulations of organosilicon compounds Multiphase formulations of organosilicon compounds

2000-12-14

2002-09-17

Dawson, Robert (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C528S012000, C528S015000, C528S031000, C528S025000, C525S479000, C525S474000, C524S081000, C524S306000

Reexamination Certificate

active

06451909

ABSTRACT:

TECHNICAL FIELD
The invention relates to multiphase formulations of organosilicon compounds, and particularly to a process for their preparation.
BACKGROUND ART
EP-A 414 938 (Nippon Unicar Company Limited, Mar. 6, 1991) describes compositions which contain a crosslinkable thermoplastic resin, an organic peroxide and a linear organopolysiloxane. The linear organopolysiloxane is obtained by reacting &agr;,&ohgr;-dihydrogensiloxanes with &agr;,&ohgr;—dienes in the presence of platinum catalysts. The linear polymers contain at least one terminal C═C double bond.
U.S. Pat. No. 5,241,034 (Wacker-Chernie GmbH, Aug. 31, 1993) discloses siloxane copolymers bearing linear or branched 1-alkenyl groups, prepared by polyaddition of hydrogensiloxanes and olefins having at least two terminal C═C double bonds so that they contain siloxane and hydrocarbon blocks alternately. The siloxane copolymers have a preferred viscosity of from 10 to 10,000 mPa·s at 25° C. The olefins having at least two terminal C═C double bonds have the disadvantage that the terminal C═C double bonds isomerize in the presence of Si—H groups and noble metal catalysts to form thermodynamically more stable internal double bonds, which are then substantially inactive to hydrosilylation, i.e. the polyaddition stops.
EP-A 874 017 (Dow Corning S.A., laid open on Oct. 28, 1998) describes a process for the preparation of a silicone-in-water emulsion, in which a composition containing two different inter-reactive linear polysiloxanes which chain extend in the presence of a hydrosilylation catalyst is emulsified in water in the presence of an emulsifier. Emulsions of polysiloxanes having a wide range of monodisperse particle sizes and molecular weights are obtained. The polyaddition of the two linear polysiloxanes is effected in the disperse phase, and emulsions of highly viscous polymers may be obtained.
DISCLOSURE OF INVENTION
It was an object of the present invention to provide a process for the preparation of multiphase formulations of organosilicon compounds, in particular a process for the preparation of aqueous emulsions of organosilicon compounds, which is simple and in which only one type of organopolysiloxane is necessary, and in which branched organosilicon compounds are also obtained. It was a further object to provide multiphase formulations of organosilicon compounds, in particular aqueous emulsions of organosilicon compounds, the organosilicon compounds having a high viscosity. These and other objects are achieved by the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The invention relates to a process for the preparation of multiphase formulations of organosilicon compounds by (A) providing a mixture comprising an organic compound (1) containing at least two aliphatic double bonds and of the general formula
R
2
(CR
1
═CH
2
)
x
,  (1)
in which
R
1
are a hydrogen atom or an alkyl radical having 1 to 6 carbon atoms per radical,
R
2
is a divalent, trivalent or tetravalent hydrocarbon radical having 1 to 25 carbon atoms per radical, and
x denotes 2, 3 or 4, corresponding to the valence of R
2
, and an organopolysiloxane (2) having on average more than one Si-bonded hydrogen atom per molecule,
a catalyst (3) which promotes the addition of Si-bonded hydrogen at an aliphatic double bond,
an emulsifier (4), and
an agent (5) immiscible with (1) and (2), and
(B) emulsifying the mixture, with the proviso that the ratio of aliphatic double bonds in organic compound (1) to Si-bonded hydrogen in the organopolysiloxane (2) of step (A) is such that toluene-soluble siloxane copolymers are obtained. In the claims, the terms “a” and “an” mean “one or more” unless indicated otherwise.
The invention furthermore relates to multiphase formulations of organosilicon compounds which can be prepared by (A) providing a mixture comprising an organic compound (1) containing at least two aliphatic double bonds, corresponding to the general formula
R
2
(CR
1
═CH
2
)
x
,  (1)
in which
R
1
are a hydrogen atom or an alkyl radical having 1 to 6 carbon atoms per radical,
R
2
is a divalent, trivalent or tetravalent hydrocarbon radical having 1 to 25 carbon atoms per radical, and
x denotes 2, 3 or 4, corresponding to the valence of R
2
, and an organopolysiloxane (2) having on average more than one Si-bonded hydrogen atom per molecule,
a catalyst (3) which promotes the addition of Si-bonded hydrogen at an aliphatic double bond,
an emulsifier (4), and
an agent (5) immiscible with (1) and (2), and (B) emulsifying the mixture, with the proviso that the ratio of aliphatic double bonds in organic compound (1) to Si-bonded hydrogen in the organopolysiloxane (2) of step (A) is such that toluene-soluble siloxane copolymers are obtained.
The process according to the invention, is preferably a process for the preparation of two-phase formulations. In the latter process, water is preferably used as the agent (5) which is immiscible with (1) and (2). Thus, aqueous dispersions, preferably aqueous emulsions, are therefore preferably obtained as multiphase formulations.
In the subject invention process, the siloxane copolymers obtained are those which are soluble in toluene, i.e. uncrosslinked siloxane copolymers are obtained, in contrast to toluene-insoluble siloxane copolymers which are crosslinked. The siloxane copolymers are soluble in toluene in any mixing ratio; they are preferably soluble in an amount of 100% by weight in toluene at a temperature of 25° C. and a pressure of about 1020 hPa, if siloxane copolymers and toluene are mixed in the ratio 1:1 (parts by weight).
In the siloxane copolymers obtained by the subject process invention, the siloxane blocks are linked to one another via hydrocarbon groups, resulting in a hydrocarbon-siloxane block structure. Preferably, the sum of the hydrocarbon groups in the siloxane copolymers is preferably from 0.1 to 70% by weight, more preferably from 0.1 to 10% by weight, based in each case on the total weight of the siloxane copolymers. The polyaddition process inevitably leads to a polymer distribution with respect to both the siloxane blocks and to the hydrocarbon blocks.
The siloxane copolymers obtained preferably have a minimum viscosity of about 20,000 mPa·s at 25° C., more preferably 500,000 mPa·s at 25° C., and most preferably 1×10
6
mPa·s at 25° C., and preferably a maximum viscosity of, up to 5×10
8
mPa·s at 25° C., more preferably up to 1×10
8
mPa·s at 25° C.
Examples of alkyl radicals R
1
are the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl and tert-pentyl radicals, and hexyl radicals such as the n-hexyl radical. R
1
is preferably a hydrogen atom.
Examples of organic compounds (1) which have at least two aliphatic double bonds and are used in the process according to the invention are 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, 3,5-dimethyl-1,6-heptadiene, 3,5-dimethyl-4-vinyl-1,6-heptadiene, 1,2,4-trivinylcyclohexane, 1,3,5-trivinylcyclohexane, 1,4-divinylbenzene and 1,2,3,4-tetravinylcyclobutane, 1,2,4-trivinylcyclohexane and 1,7-octadiene being preferred.
Examples of the radical R
2
are therefore those of the formula
—(CH
2
)
2
—, —(CH
2
)
4
—, —(CH
2
)
6
—, —(CH
2
)
8
—, —(CH
2
)
10
—, —C
6
H
4
—,
the radicals of the formula
and
—(CH
2
)
4
—
being preferred.
Preferably, the organopolysiloxanes (2) used in the process according to the invention contain on average at least 1.5 Si-bonded hydrogen atoms, preferably on average at least 2 Si-bonded hydrogen atoms, per molecule. Most preferably, the organopolysiloxanes (2) used in the process according to the invention contain from 2 to 4 Si-bonded hydrogen atoms per molecule.
In the process of the invention, one type of organopolysiloxane (2) or different types of organopolysiloxane (2) can be used. As a result of their method of preparation, organopolysiloxanes (2) are generally mixtures, i.e., organopolysiloxanes having 2 Si-bonded hydrogen atoms per molecule contain some organopolysilox

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