Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Reexamination Certificate
2000-06-02
2001-06-26
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C556S453000, C528S015000, C427S445000
Reexamination Certificate
active
06252100
ABSTRACT:
TECHNICAL FIELD
The invention relates to a process for the preparation of linear organopolysiloxanes having &agr;,&ohgr;-terminal Si-bonded alkenyl groups or &agr;,&ohgr;-terminal Si-bonded hydrogen atoms.
DESCRIPTION OF THE RELATED ART
U.S. Pat. No. 5,442,083 (Dow Corning Toray Silicone; published on Aug. 15, 1995) describes a process for the preparation of linear organopolysiloxanes having &agr;,&ohgr;-terminal Si-bonded vinyl groups or &agr;,&ohgr;-terminal Si-bonded hydrogen atoms by reacting an &agr;,&ohgr;-dihydrogendimethylpolysiloxane with an aliphatically unsaturated hydrocarbon having two C═C double bonds and at least three carbon atoms or with an alkyne having at least two carbon atoms in the presence of hydrosilylation catalysts.
EP-A 414 938 (Nippon Unicar Company Limited; laid open on Mar. 6, 1991) discloses a crosslinkable composition which contains a thermoplastic resin and a linear organopolysiloxane, the linear organopolysiloxane being obtained by reacting a linear organopolysiloxane having terminal Si-bonded hydrogen atoms with a linear diene having more than five carbon atoms.
U.S. Pat. No. 5,087,720 (Shin-Etsu Chemical Co.; published on Feb. 11, 1992) describes linear organopolysiloxanes having terminal Si-bonded vinyl groups, which have repeating units of the formula —(SiR
2
—CH
2
CH
2
—SiR
2
O)
n
— in the chain. Preparation is carried out via ring-opening polymerization of a 5-membered cyclic silethylenesiloxane of the general formula
in the presence of a divinyldisiloxane. U.S. Pat. No. 5,386,049 (Shin-Etsu Chemical Co.; published on Jan. 31, 1995) discloses linear organopolysiloxanes having terminal Si-bonded hydroxyl groups or vinyl diorganosilyl groups, which have repeating units of the formula —[SiMe
2
—(CH
2
)
p
—SiMe
2
O]
n
—(Me=methyl radical, p=10-16) in the chain.
U.S. Pat. No. 5,504,175 (Dow Corning Toray Silicone Co.; published on Apr. 2, 1996) describes linear organosilicon polymers having terminal Si-bonded hydrogen atoms or terminal Si-bonded alkenyl groups, which are obtained by reacting an asymmetric linear &agr;-hydrogen-&ohgr;-alkenyldiorganopolysiloxane with a symmetrical linear &agr;,&ohgr;-dihydrogendiorganopolysiloxane or &agr;,&ohgr;-dialkenyl-diorganopolysiloxane in the presence of a hydrosilylation catalyst. This process requires an asymmetric diorganopolysiloxane whose precise preparation is complicated and expensive and hence industrially not very attractive.
SUMMARY OF THE INVENTION
It was the object to provide a process for the preparation of linear organopolysiloxanes having &agr;,&ohgr;-terminal Si-bonded alkenyl groups or &agr;,&ohgr;-terminal Si-bonded hydrogen atoms, which is simple, in which the formation of low molecular weight volatile or cyclic byproducts is avoided and in which the starting materials used can be easily purified. In particular, it was the object to provide a process in which aqueous emulsions which contain highly polymeric organopolysiloxanes may be prepared at all and in a simple manner.
The object is achieved by the invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a process for the preparation of linear organopolysiloxanes having &agr;,&ohgr;-terminal Si-bonded &ohgr;-alkenyl groups or &agr;,&ohgr;-terminal Si-bonded hydrogen atoms and of the general formula
XR
2
SiO(R
2
SiO)
x
—G
y
—R
2
Si—[R
3
—R
2
SiO (R
2
SiO)
x
—G
y
—R
2
Si]
2
X (I)
by reacting Si-bonded organopolysiloxanes having &ohgr;-alkenyl groups and of the general formula
R
1
R
2
SiO(R
2
SiO)
m
—A
n
—R
2
SiR
1
(II)
with Si-bonded organopolysiloxanes having hydrogen atoms and of the general formula
R
2
R
2
SiO(R
2
SiO)
o
—B
p
—R
2
SiR
2
(III)
in the presence of catalysts promoting the addition of Si-bonded hydrogen at an aliphatic multiple bond,
where R denotes an optionally substituted hydrocarbon radical having 1 to 18 carbon atom(s) per radical,
X denotes in each case identical radicals selected from the radicals R
1
and R
2
,
where R
1
denotes an &ohgr;-alkenyl radical having 2 to 18 C atoms,
R
2
denotes a hydrogen atom,
R
3
is a bifunctional &agr;,&ohgr;-alkanediyl radical having 2 to 18 C atoms,
G is a radical A or B,
where A is a radical of the formula
—R
2
S—R
4
—R
2
SiO(R
2
SiO)
m
—
and B is a radical of the formula
—R
2
Si—R
4
—R
2
SiO(R
2
SiO)
o
—
where
R
4
denotes a divalent hydrocarbon radical having 2 to 14 carbon atoms per radical, which may be interrupted by
1 to 4 separate oxygen atoms,
m is 0 or an integer having a value of 1 to 2000,
n is 0 or an integer having a value of 1 to 20,
o is 0 or an integer having a value of 1 to 2000,
p is 0 or an integer having a value of 1 to 20,
x is m or o,
y is n or p and
z is an integer having a value of at least 2, preferably 5 to 20,
with the proviso that the sum m+n is ≧0.
The organopolysiloxanes prepared by the process according to the invention preferably have a viscosity of 20 to 200,000,000 MM
2
/s at 25° C., preferably 2000 to 100,000,000 mm
2
/s at 25° C. and particularly preferably 100,000 to 20,000,000 mm
2
/s at 25° C.
Examples of radicals R are alkyl radicals, such as the methyl, ethyl, n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl or tert-pentyl radical; hexyl radicals, such as the n-hexyl radical; heptyl radical, such as the n-heptyl radical; octyl radicals, such as the n-octyl radical and isooctyl radicals, such as the 2,2,4-trimethylpentyl radical; cycloalkyl radicals, such as cyclopentyl, cyclohexyl and cycloheptyl radicals and methylcyclohexyl radicals; aryl radicals, such as the phenyl radical, alkaryl radicals, such as the o-, m- and p-tolyl radicals, xylyl radicals and ethylphenyl radicals, and aralkyl radicals, such as the benzyl radical and the &agr;- and the &bgr;-phenylethyl radical. The methyl radical is preferred.
Examples of halogenated radicals R are haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2′,2′,2′-hexafluoroisopropyl radical and the heptafluoroisopropyl radical, and haloaryl radicals, such as the o-, m- and p-chlorophenyl radical.
Examples of radicals R
1
are the vinyl, allyl, 3-butenyl, 5-hexenyl, 7-octenyl, 9-decenyl and 13-tetradecenyl radical. The vinyl and the 5-hexenyl radical are preferred, and the vinyl radical is particularly preferred.
Examples of radicals Y are those of the formula —CH
2
CH
2
—, —CH(CH
3
)—, —(CH
2
)
4
—, —(CH
2
)
5
—, —CH
2
)
6
—(CH
2
)
8
—, —(CH
2
)
10
—, —(CH
2
)
12
—, —(CH
2
)
3
O(CH
2
)
3
—, 1,3-(CH
2
CH
2
)
2
(C
6
H
4
), 1,4-(CH
2
CH
2)
2
(C
6
H
4
) and 1,3-(CH
2
CHCH
3
)
2
(C
6
H
4
), where the radical of the formula —CH
2
CH
2
— is preferred.
m is preferably an integer having a value of 1 to 1000, preferably 10 to 1000, particularly preferably 100 to 500.
o is preferably an integer having a value of 1 to 1000, preferably 10 to 1000, particularly preferably 100 to 500.
n is preferably 0 or an integer having a value of 1 to 5;
n is preferably 0.
p is preferably 0 or an integer having a value of 1 to 5;
p is preferably 0.
Processes for the preparation of organopolysiloxanes of the formulae (II) and (III) are known to a person skilled in the art.
In the process according to the invention, the ratio of Si-bonded &ohgr;-alkenyl groups in organopolysiloxanes of the formula (II) to Si-bonded hydrogen atoms in organopolysiloxanes of the formula (III) which is used may vary within wide limits depending on the desired end product. In the process according to the invention, the ratio of Si-bonded &ohgr;-alkenyl groups in organopolysiloxanes of the formula (II) to Si-bonded hydrogen atoms in organopolysiloxanes of the formula (III) is preferably 100:1 to 1:100, preferably 5:1 to 1:5, particularly preferably 1.5:1 to 1:1.5, very particularly preferably 1.3:1 to 1:1.3, it being possible to obtain particularly high molecular weight products in the range 1.1:1 to 1:1.1. With a stoichiometric excess of Si-bonded &ohgr;-alkenyl groups, polymers having hydrocarbon bridges —C
2
H
4
— along the chain and one Si-bonded &ohgr
Brooks & Kushman P.C.
Shaver Paul F.
Wacker-Chemie GmbH
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