Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-12-03
2001-07-17
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C528S039000, C528S015000, C528S014000, C528S031000, C528S026000, C528S027000, C528S034000, C156S329000, C524S588000
Reexamination Certificate
active
06262188
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to addition cure silicone polymer compositions. In particular, this invention relates to addition cure silicone polymer compositions comprising a functionalized silicone riesin as an effective adhesion-enhancing additive.
Addition cure silicone adhesives are a commercially important class of adhesives. A typical addition cure composition comprises an alkenyl-group containing organopolysiloxane, an organohydrogenpolysiloxane, and a catalyst. The adhesiveness of these compositions is often improved by addition of one or more adhesion-promoting additives (adhesion promoters). Several U.S. patents, for example U.S. Pat. Nos. 3,996,195, 4,257,936, 4,855,351, 5,405,896, and 5,405,094 describe certain organofunctional silanes and oligosiloxanes usable as adhesion enhancing additives for addition cure silicone adhesives. These compounds are most often organovinyloxysilanes, or cyclic or linear organooligosiloxanes comprising various organic functionalities, such as glycidyl, carbonyl, carbonyloxy, silyloxy or alkoxysilyl groups, as well as optional Si—H functional groups. Such compounds are typically mixed with an addition cure silicone adhesive master batch in ratios in the range of 0.1-10 parts additive to 100 parts master batch. The resulting silicone adhesive can be applied to substrates such as metals, plastics or glass, and cured by exposure to heat. The cured silicon will strongly adhere to the substrates.
There are two major disadvantages of the above-described and other known adhesion promoters. The first is their substrate selectivity. Polycarbonates are an example of substrates to which adhesion is very difficult. The second disadvantage is the negative impact that adhesion promoters have on the cure rate of the adhesive, sometimes slowing cure to commercially unacceptable levels. There is thus a continued need for new adhesion-enhancing additives which will promote adhesion to a wide range of substrates, and which will allow cure at low temperature.
SUMMARY OF THE INVENTION
The above-described and other disadvantages of the prior art are alleviated by the compositions of the present invention, comprising functionalized resins having the formula
M
x
H
M
y
R
Q (I)
wherein x+y is in the range of 0.5 to 4, the ratio x:y is in the range of 1:10 to 10:1, and
Q is SiO
{fraction (4/2)}
M
H
is R
1
R
2
HSiO
½
M
R
is R
1
R
2
RSiO
½
wherein each R
1
and R
2
is independently an alkyl, fluoroalkyl, or aryl group having from 1 to about 18 carbons, and R can be the same or different and is selected from the group consisting of the formulas (II), (III) and (IV):
—CH
2
BOC(O)Ar (II)
wherein Ar is a phenyl or substituted phenyl group, B is a branched or straight-chain alkylene group having from 1 to 12 carbon atoms;
—CH
2
CH
2
Ep (III)
wherein Ep is an organic radical containing an epoxy functional group selected from the group consisting of:
wherein B is as previously defined; and
—A
1
—C(O)O—A
2
—Si(OR
1
)
3
(IV)
wherein A
1
is a branched or straight-chain alkylenec group having from 2 to 12 carbon atoms and A
2
is a branched or straight-clhain alkylene group having from 2 to 16 carbon atoms, and R
1
is as defined above.
In the method of the present invention, such functionalized resins are produced by reaction, in the presence of a precious metal catalyst, of an organohydrogensiloxane having the formula
M
Z
H
Q (V)
wherein z is in the range from 0.5 to 4, Q is as defined above, and
M
H
is R
1
R
2
HSiO
½
wherein R
1
and R
2
are as defined above, with a less than stoichiometric amount of an unsaturated compound or compounds of formulas (VI), (VII), and silanes of formula (VIII) presented below:
H
2
C═CH(CH
2
)
w
OC(O)Ar (VI)
wherein Ar is a phenyl or substituted phenyl group, and w is 0 or an integer wherein 1≦w≦8;
H
2
C═CHEp (VII)
wherein Ep is an organic radical containing an epoxy functional group as defined above; or
H
2
C═CR
3
—B—C(O)O—A
2
—Si(OR
1
)
3
(VIII)
wherein B is absent or a branched or straight-chaini alkylene group having from 4 to 12 carbon atoms, A
2
and R
1
are as defined above and R
3
is hydrogen or a methyl group.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of the present invention comprise functionalized silicone resins having the formula
M
x
H
M
y
R
Q (I)
wherein x+y is in the range from 0.5 to 4 (including 0.5 and 4) and the ratio x:y is in the range from 1:10 to 10:1. Preferably, the ratio x:y ranges from 3:10 to 10:3. Formula (I) is written using the well-known nomenclature for silicones wherein
Q is SiO
{fraction (4/2)}
M
H
is R
1
R
2
HSiO
½
M
R
is R
1
R
2
RSiO
½
wherein each R
1
and R
2
is independently an alkyl, fluoroalkyl, or aryl group having from 1 to about 18 carbons, preferably monovalent hydrocarbons having from one to three carbons, and most preferably methyl groups. Thus, formula (I) may also be written as
(R
1
R
2
HSiO
½
)
x
(SiO
{fraction (4/2)}
)(R
1
R
2
RSiO
½
)
y
wherein x, y, R
1
and R
2
are as defined above, and R can be the same or different and is selected from the group consisting of the formulas (II), (III) or (IV):
—CH
2
BOC(O)Ar (II)
wherein Ar is a phenyl or substituted phenyl group, B is a branched or straight-chain alkylene group having from 1 to 12 carbon atoms;
—CH
2
CH
2
Ep (III)
wherein Ep is an organic radical containing an epoxy group selected from the following:
wherein B is a branched or straight-chain alkylene group having from 1 to 12 carbon atoms; and
—A
1
—C(O)O—A
2
—Si(OR
1
)
3
(IV)
wherein A
1
a branched or straight-chain alkylene group having from 2 to 12 carbon atoms and A
2
is a branched or straight-chain alkylene group having from 1 to 16 carbon atoms, and R
1
is as defined above. Preferably, A
1
is —CH
2
CH
2
— or —CH
2
CH(CH
3
)—, and A
2
has from 2 to 12, preferably from 2 to 6 carbon atoms.
In accordance with the present method, it has been discovered that functionalized resins (I) may be produced by the metal-catalyzed reaction of an organohydrogensiloxane having the formula
M
Z
H
Q (V)
wherein z is in the range from 0.5 to 4 (including 0.5 and 4). Q is as defined above, and
M
H
is R
1
R
2
HSiO
½
wherein R
1
and R
2
are as defined above. Preferably, R
1
and R
2
are methyl. Formula (V) may also be written as
(R
1
R
2
HSiO
½
)
z
SiO
{fraction (4/2)}
wherein z, R
1
and R
2
are as defined above.
Organohydrogensiloxane (V) is reacted with a less than stoichiometric amount of an unsaturated compound or mixture of compounds of formulas (VI), (VII), and silanes of formula (VIII) below:
H
2
C═CH(CH
2
)
w
OC(O)Ar (VI)
wherein Ar is a phenyl or substituted phenyl group, and w is 0 or an integer wherein 1≦w≦8;
H
2
C═CHEp (VII)
wherein Ep is an organic radical containing an epoxy functional group as defined above; or
H
2
C═CR
3
—B—C(O)O—A
2
—Si(OR
1
)
3
(VIII)
wherein B is absent or a branched or straight-chaini alkylene group having from 1 to 10 carbons, and A
2
and R
1
are as defined above and R
3
is hydrogen or a methyl group. Preferably, B is absent and R3 is hydrogen. Preferred unsaturated epoxides of formula (VII) are shown below:
Preferred silanes (VIII) have the formula (IX)
H
2
C═CHC(O)OCH
2
CH
2
CH
2
Si(OCH
3
)
3
(IX)
In an important feature of the method, the molar ratio of Si—H functional groups in organohydrogensiloxane (V) to reactive alkylene groups in (VI), (VII), or (VIII) is in the range from about 10:1 to about 10:9, and preferably in the range from about 10:3 to about 10:7. Most preferably, the ratio is about 10:5 and the unsaturated compounds are methacryloxypropyltrimethoxysilane and allylgilyclidylether.
Effective catalysts for the reaction of (V) with (VI), (VII), or (VIII) are precious metals and complexes of precious metals such as platinum, rhodium, ruthenium, and palladium, osmium, and irid
Burkus, II Frank S.
Gulinski Jacek
Marciniec Bogdan
Rubinsztajn Slawomir
Dawson Robert
General Electric Company
Peng Kuo-Liang
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