Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1999-10-27
2001-03-06
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S049000, C525S453000, C525S474000, C556S421000
Reexamination Certificate
active
06197912
ABSTRACT:
BACKGROUND OF THE INVENTION
Urethane prepolymers have been modified in the past to improve or add to their basic properties by end-capping some or all of the isocyanate groups with various organofunctional silanes. Among these methods, U.S. Pat. No. 3,632,557 describes the complete end-capping of conventional polyurethane prepolymers with primary and secondary aliphatic aminosilanes. U.S. Pat. No. 3,979,344 details a room temperature curable silicon terminated organic sealant composition comprising a small quantity of 3-(N-2-aminoethyl)aminopropyltrimethoxysilane to improve the sealant's cure speed. U.S. Pat. No. 4,222,925 describes compositions as is given in U.S. Pat. No. 3,979,344 but which also incorporate a reinforcing carbon black filler. Sealants having improved elongation and flexibility were prepared using silane end-capped polyurethane polymers obtained from silane monomers having at least one dialkoxy group and an organofunctional group with at least one active hydrogen atom in U.S. Pat. No. 4,645,816.
However, polyurethane prepolymers end-capped with primary aminofunctional silanes contain an active hydrogen atom which is capable of further reactions with the isocyanate end groups. This reactivity can lead to undesirable instability of both the polymer and sealant compositions. Several methods use secondary aminofunctional silane endcappers. For example, U.S. Pat. No. 4,374,237 describes the curable isocyanate terminated polyurethane prepolymers at least part of whose terminal isocyanate groups have been reacted with a secondary amine containing silane monomer having two trialkoxy silane groups. U.S. Pat. No. 4,474,933 describes crosslinkable polyurethane resin mixtures that have been capped with various primary and secondary difunctional aminosilane endcappers. Other references of interest relating to silane end-capped urethane prepolymers and sealants are U.S. Pat. No. 3,627,722; U.S. Pat. No. 4,067,844; U.S. Pat. No. 4,625,012; U.S. Pat. No. 4,345,053; U.S. Pat. No. 4,645,816; and U.S. Pat. No. 5,354,880.
In EP 676 403 Al there are described arylaminoisobutylalkyldialkoxy silanes useful as end cappers for isocyanate polymers.
It is an object of the present invention to provide novel silane compositions useful for instance as sealants, coatings, and the like, based upon urethane prepolymers end-capped with certain N-alkyl-aminoalkylsilanes.
BRIEF SUMMARY OF THE INVENTION
One aspect of the present invention is a composition of matter which is a moisture cureable polymer characterized by having a plurality of terminal or pendant groups of the formula:
thereon, where
R
1
represents an alkyl group having 1 to 10 carbon atoms optionally interupted with one or more ether oxygen atoms, most preferably an ethyl group, or a group of the formula
R
2
represents a C
1
to C
6
alkoxy group or a C
6
-C
8
aryloxy group;
R
3
represents an alkyl, preferably having 1 to 6 carbon atoms, or an aryl group, preferably having 6-8 carbon atoms;
T represents a branched or cyclic alkylene radical of 4 to 10 carbons, which may be optionally interrupted by one or more ether oxygen atoms;
X is an alkylene group of 3-10 carbon atoms, which may be linear, branched or cyclic; and
a is 0, 1 or 2.
Another aspect of the present invention is a composition of matter which is the product of reacting (A) a compound having at least two isocyanate groups thereon with (B) a silane of formula (3):
where T, R
1
, R
2
, R
3
, and a are as previously defined. The isocyanate functional compound may be a prepolymer compound prepared by reacting a polyol component with an excess of difunctional or polyfunctional isocyanate so that said prepolymer contains unreacted isocyanate groups.
Still other aspects of the present invention are curable formulations useful for instance as sealants, containing the aforementioned composition of matter together with a cure catalyst and one or more conventional functional adjuvants selected from the group consisting of fillers, plasticizers, thixotropes, ultraviolet stabilizers, and adhesion promoters.
Yet another aspect of the present invention is the process of making a composition of matter which upon curing exhibits improved thermal stability, elongation, tensile strength and tear resistance, comprising reacting the aforementioned prepolymer (A) with a silane of the aforementioned formula (3).
DETAILED DESCRIPTION OF THE INVENTION
The entire disclosures of all US patents and other published documents and any copending US patent applications mentioned anywhere herein are expressly incorporated herein by reference.
Unless otherwise indicated herein, “alkyl”may be linear, branched or cyclic; “aryl” includes alkaryl groups such as tolyl, and aralkyl groups such as benzyl; and “alkylene” may be linear, branched or cyclic and includes alkylene groups having pendent or internal aryl groups such as 1,4-diethylenephenylene:
or 3-phenyl-1,3-propylene;
Referring to formulae (1) and (3) above, T is exemplified by isobutylene (i.e. 2-methylpropylene: —CH
2
CH(CH
3
)CH
2
—), 2,2-dimethylethylene (i.e. with branching distal from the silicon atom), 1-methylpropylene, 3-methylpropylene, 2,2-dimethylpropylene, 3-methylbutylene, 3,3-dimethylbutylene, 2-ethylhexylene, isopropoxypropylene (i.e. —CH
2
CH(CH
3
)—O(CH
2
)
3
—), isopropoxyisobutylene (i.e. —CH
2
CH(CH
3
)—OCH
2
CH(CH
3
)CH
2
—) and the like. Branching is preferably distal to the carbon atom to which the silicon atom in formulae (1) and (3) is bound. Isobutylene is preferred. T may also be an alkylene group comprising a cyclic hydrocarbon moiety such as a cyclopentylene, 1,4-cyclohexylene, 1,4-diethylenecyclohexylene:
and 1,4-diethylenephenylene:
R
1
, as an optionally interrupted alkyl group, is exemplified by methyl, ethyl, propoxyethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, hexyl, 2-ethylhexyl, octyl, nonyl, decyl, ethoxymethyl, ethoxyethyl, propoxyethyl, ethoxypropyl, ethoxyethoxypropyl and the like. R
1
, as a group of formula (2), is exemplified by trimethoxysilylpropyl, triethoxysilylpropyl, 3-trimethoxysilyl-2-methylpropyl, 3-trimethoxysilyl- 1-methylpropyl, 3-dimethoxymethylsilylpropyl 2-(4-trimethoxysilylethyl)cyclohexylethyl, and the like.
X is exemplified by 1,2-propylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, and the like and by the exemplary T groups previously identified.
R
2
is exemplified by methoxy, ethoxy, isopropoxy, n-propoxy, phenoxy, tolyloxy, and the like. Methoxy and ethoxy are preferred.
R
3
is exemplified by methyl, ethyl, propyl, isopropyl, butyl, hexyl, phenyl, tolyl, dimethylphenyl, ethylphenyl and the like. Preferably R
2
is not present (a=0) or is a methyl group.
Exemplary silanes of formula (3) include:
N-methyl-3-amino-2-methylpropyltrimethoxysilane,
N-ethyl-3-amino-2-methylpropyltrimethoxysilane,
N-ethyl-3-amino-2-methylpropyldiethoxymethylsilane,
N-ethyl-3-amino-2-methylpropyltriethoxysilane,
N-ethyl-3-amino-2-methylpropylmethyldimethoxysilane,
N-butyl-3-amino -2-methylpropyltrimethoxysilane,
3-(N-methyl-2-amino-1-methyl-1-ethoxy)-propyltrimethoxysilane,
N-ethyl-4-amino-3,3-dimethylbutyldimethoxymethylsilane,
N-ethyl-4-amino-3,3-dimethylbutyltrimethoxysilane,
bis-(3-trimethoxysilyl-2-methylpropyl)amine and
N-(3′-trimethoxysilylpropyl)-3-amino-2-methylpropyltrimethoxysilane.
Silanes of formula (3) can be prepared by hydrosilylation of a corresponding secondary amino branched or cyclic alkene with an alkoxyhydridosilane, ot aryloxyhydridosilane. Trialkoxyhydridosilanes are preferred. Suitable reaction conditions are illustrated in the examples below. Alternatively one can react such an alkenylamine with a hydridochlorosilane, and the resulting aminoalkylchlorosilane subsequently esterified to the corrsponding alkoxy or aryloxy silane.
Preparation of Polymers
Isocyanate functional prepolymers having organic and inorganic backbones are well known. Organic backbone polymer systems include acrylics, polyurethanes, polyethers, polyesters, polyolefins and others. Inorganic backbone systems are exemplified by polyorganosiloxanes. Preferred polym
Huang Misty Weiyu
Waldman Bruce A.
CK Witco Corporation
Gorr Rachel
Ma, Esq. Shirley S.
LandOfFree
Silane endcapped moisture curable compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silane endcapped moisture curable compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silane endcapped moisture curable compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2473625