Mixed alkoxysilyl functional polymers

Abstract

This invention relates to silylated polymers having mixed alkoxy groups on the silyl portion thereof, methods of their preparation, and compositions and reaction products formed therefrom. These alkoxysilylated polymers can be crosslinked when expoesed to atmospheric moisture to become useful elastomers, sealants or adhesives. The presence of different alkoxy groups on the silicon atoms can control or otherwise moderate the cure speeds of these silylated polymers.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to silylated polymers having mixed alkoxy groups on the silyl portion thereof, methods of their preparation, and compositions and reaction products formed therefrom. These alkoxysilylated polymers can be crosslinked when exposed to atmospheric moisture to become useful elastomers, sealants or adhesives. The presence of different alkoxy groups on the silicon atoms can control the cure speeds of these silylated polymers.

[0003] 2. Background of Related Technology

[0004] Alkoxysilylated polymers, in the presence of a catalyst, can be crosslinked by atmospheric moisture under ambient conditions. Compositions based on these type of polymers are often referred to as RTV sealants (or adhesives). The most well known example is RTV silicone sealants.

[0005] Crosslinking of alkoxysilylated polymers involves hydrolysis and condensation reactions of the alkoxylsilyl group. The cure speed of compositions prepared therefrom has conventionally been accelerated through the use of various types and amounts of moisture cure catalysts. However, among the disadvantages of using increased amounts of such catalysts to obtain greater cure speeds are potential instability, loss of shelf life and enhanced manufacturing and material costs of such compositions.

[0006] The smaller alkoxy groups, e.g. methoxy, are ordinarily more reactive and thus better able to be displaced by another chemical entity. Therefore, methoxy groups are more desirable for obtaining moisture curable polymers having faster and/or more controlled cure speeds. Currently, however, the starting materials for making many lower alkoxy group-containing polymers with a variety of backbones, such as polyethers like polypropylene oxide (“PPO”), are not readily commercially available. For example, a desirable route for making silyl-terminated PPO polymers containing alkoxy groups might include reacting an isocyanatoalkyltrialkoxysilane with an hydroxy terminated PPO. However, presently trimethoxysilyl-terminated isocyanatoalkyl compounds are not widely commercially available.

[0007] Thus, there is a need for a method of conveniently producing a moisture curable composition which includes a curable polymer having a mixture of different alkoxy groups present, at least one of which being a methoxy group, whereby controlled moisture cure speed is obtained.

SUMMARY OF THE INVENTION

[0008] In accordance with the present invention, moisture cure speed can be controlled to proceed in a more or less rapid manner, depending on the identity and number of the alkoxy groups on the curable alkoxysilyl polymer. For example, methoxy and ethoxy groups are contemplated as being present concurrently on the silyl groups of the polymers of the present invention, though the methoxy groups provide more rapid cure.

[0009] One aspect of the invention relates to the presence of different alkoxy groups on the silicon atom of a silyl endcapped moisture curable polymer, whereby controlled cure speed of the moisture curable polymer is obtained. The presence of larger alkoxy groups, such as ethoxy or greater, slow down the cure while smaller alkoxy groups, such as methoxy, accelerate it. The overall cure speed is related to the type or combination of alkoxy group(s) or groups on the silicon. As noted above, the cure speed is faster if the alkoxy group is a better leaving group. Typically, a smaller alkoxy group is a better leaving group. For example, a methoxysilylated polymer cures faster than an ethoxysilylated polymer or a butoxysilylated polymer.

[0010] Another aspect of the invention relates to a moisture curable composition which includes an alkoxylsilyl terminated polymer containing more than one type of alkoxy group. Desirably, the alkoxy groups are at the terminal ends of the polymer, though pendant groups are also contemplated. The backbone of the polymer can be varied and may be chosen from a wide range of materials. PPO is among the desirable backbones.

[0011] A further aspect of the present invention relates to a reaction product formed from the aforementioned polymer having mixed alkoxysilyl functional groups and a catalyst.

[0012] In still another aspect of the invention, there is provided a method for preparing mixed alkoxysilyl polymers via an alkoxy exchange reaction. This process includes mixing a polymer having at least one alkoxysilyl group present, an alkoxysilane and a catalyst. Desirably, the alkoxysilane contains a methoxy group which exchanges with a higher carbon number alkoxy on the alkoxysilyl polymer. The resultant alkoxy exchange reaction desirably provides a mixture of different alkoxy groups, e.g. methoxy, ethoxy and the like on the reactive polymer. The alkoxy exchange can occur slowly at room temperature, but desirably occurs at higher temperatures in the presence of a catalyst.

[0013] In yet another aspect of the invention, there is included a reactive polymer having the structure: 1

[0014] wherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages; A and A′ may be each C1-30 linear or branched, substituted or unsubstituted aliphatic groups or aromatic-containing groups, with or without interuption by a carboxy, carbamate, carbonate, ureido, urethane or sulfonate linkage; n may be 0 or 1; R1 and R2 may be each substituted or unsubstituted C1-12 alkyl or aryl groups; R3 is a C1-12 alkyl, alkenyl, alkoxy, aminoalkyl or aryl group, or a (meth)acryloxyalkyl group.

[0015] This polymer can be combined with a catalyst and other components to form a curable composition.

[0016] A further aspect of the invention includes a curable composition which includes:

[0017] (a) a polymer having the structure 2

[0018] wherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages; A and A′ may be each C1-30 linear or branched, substituted or unsubstituted aliphatic groups or aromatic-containing groups, with or without interuption by a carboxy, carbamate, carbonate, ureido, urethane or sulfonate linkage; n may be 0 or 1; R1 and R2 may be each substituted or unsubstituted C1-12 alkyl or aryl groups; R3 is a C1-12 alkyl, alkenyl, alkoxy, aminoalkyl or aryl group, or a (meth)acryloxyalkyl group.

[0019] (b) a catalyst.

[0020] A further aspect of the invention includes the reaction product of:

[0021] (a) a polymer having at least one pendent or terminal alkoxysilyl group thereon and being a member selected from the group consisting of polyethers, polyolefins, polyesters, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof;

[0022] (b) an alkoxysilane; and

[0023] (c) a catalyst.

[0024] Still a further aspect of the invention includes a method of making an alkoxysilyl endcapped polymer, which includes the steps of reacting a first reactant having the structure:

HO—R—OH

[0025] wherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages, with a second reactant having one end terminating with an isocyanate group and another end terminating with a silyl group having at least two alkoxy groups attached to a silicon atom thereof, and providing a third reactant, such as an alkoxy silane. An example of the first reactant is hydroxyl terminated PPO; an example of the second reactant is isocyanatopropyltriethoxy silane; and examples of the third reactant include methyltrimethoxy silane, methyltriethoxy silane, vinyltrimethoxy silane, vinyltriethoxy silane, and the like.

[0026] Another aspect of the invention includes reacting an organic alcohol terminated compound such as PPO terminated with OH groups, with an isocyanatoalkyltrialkoxysilane, such as isocyanatopropyltriethoxysilane, in the presence of a catalyst such as a tin catalyst, or desirably a titanium alkylate such as titanium tetraisopropoxide, or a metal alkoxide such as sodium methoxide. The resultant composition provides a polymer which can then undergo alkoxy exchange when placed in the presence of a different alkoxy group such as a methoxysilane. This results in a mixed alkoxysilyl polymer composition having controlled, moderated or accelerated moisture cure speed.

[0027] The preparation of the mixed alkoxysilyl polymer can also be performed concurrently with the compounding of a moisture curable composition. For example, the polymer having at least one alkoxysilyl group, the alkoxysilane and the catalyst can be admixed with other components used to make the final moisture curable product. In this method, the alkoxy exchange occurs in situ in the final product without subjecting the controlled moisture curing reactive polymer per se to a pre-reaction or formation step prior to compounding.

[0028] Another aspect of the invention includes mixing a polymer having at least one alkoxysilyl group with an alcohol in the presence of a catalyst. The mixture is then aged at ambient temperature or elevated temperature to permit alkoxy exchange, thereby forming a mixed alkoxysilyl-containing reactive polymer.

DETAILED DESCRIPTION OF THE INVENTION

[0029] The invention relates to mixed alkoxysilyl polymers, curable polymers and compositions made therefrom.

[0030] The present invention recognizes that the cure speeds of polymers can be manipulated by putting different alkoxy groups on the silyl end groups of polymers encapped therewith. Cure speeds decrease in the order of MeO>EtO and higher. In one aspect of the invention, there is a method of providing mixed alkoxsilyl endcapping of polymers by reacting an hydroxy terminated polypropylene oxide polymer with a 3-isocyanatopropyltriethoxysilane and mixing the resultant reaction product with an alkoxysilane having a different alkoxy group, e.g. a methoxy group, than the reaction product, and allowing alkoxy exchange to occur, desirably in the presence of a catalyst, to form the mixed alkoxysilyl polymer. Cure speed of the resultant polymer is intermediate between those endcapped with pure 3-isocyanatopropyltrimethoxysilane and those encapped with pure 3-isocyanatopropyltriethoxysilane.

[0031] Curable polymers made and used in accordance with the present invention include, but are not limited to, those having the structure: 3

[0032] wherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages; A and A′ may be each C1-30 linear or branched, substituted or unsubstituted aliphatic groups or aromatic-containing groups, with or without interuption by A may also be a carboxy, carbamate, carbonate, ureido, urethane or sulfonate linkage; n may be 0 or 1; R1 and R2 may be each substituted or unsubstituted C1-12 alkyl or aryl groups; R3 is a C1-12 alkyl, alkenyl, alkoxy, aminoalkyl or aryl group, or a (meth)acryloxyalkyl group.

[0033] Additional examples of R backbones include alkyd resins, oil modified alkyd resins, unsaturated polyesters, natural oils, (e.g., linseed, tung, soybean), epoxides, nylons, thermoplastic polyesters (e.g., polyethyleneterephthalate, polybutyleneterephthalate), polycarbonates, polyethylenes, polybutylenes, polystyrenes, polypropylenes, ethylene propylene co- and terpolymers, acrylics (homopolymer and copolymers of acrylic acid, acrylates, mathacrylates, acrylamides, their salts, hydrohalides, and the like), phenolic resins, polyoxymethylene (homopolymers and copolymers), polyurethanes, polysulfones, polysulfide rubbers, nitrocelluloses, vinyl butyrates, vinyls (e.g., vinyl chloride and/or vinyl acetate containing polymers), ethyl cellulose, the cellulose acetates and butyrates, viscose rayon, shellac, waxes, ethylene copolymers (e.g., ethylenevinyl acetate copolymers, ethyleneacrylic acid copolymers, ethyleneacrylate copolymers), organic rubbers, silicone greases, resins and rubbers and the like. Still additional examples of R include polyethers, such as polyethylene oxide (“PEO”), PPO and polyTHF.

[0034] R may also include natural rubber; those formed from the homopolymerization of butadiene and its homologues and derivatives such as: cis-1,4-polyisoprene; 3,4-polyisoprene; cis-1,4-polybutadiene; trans-1,4-polybutadiene; 1,2-polybutadiene; and those formed from the copolymerization of butadiene and its homologues and derivatives with one or more copolymerizable monomers containing ethylenic unsaturation such as styrene and its derivatives, vinyl-pyridine and its derivatives, acrylonitrile, isobutylene and alkyl-substituted acrylates such as methylmethacrylate. Examples include styrene-butadiene copolymer rubber composed of various percentages of styrene and butadiene and employing the various isomers of butadiene as desired (hereinafter “SBR”); terpolymers of styrene, isoprene and butadiene polymers, and their various isomers; acrylonitrile-based copolymer and terpolymer rubber compositions; and isobutylene-based rubber compositions; or a mixture thereof, as described in, for example, U.S. Pat. Nos. 4,530,959; 4,616,065; 4,748,199; 4,866,131; 4,894,420; 4,925,894; 5,082,901; and 5,162,409.

[0035] Other suitable organic polymers useful as R backbones are copolymers of ethylene with other high alpha olefins such as propylene, butene-1 and pentene-1 and a diene monomer. The organic polymers may be block, random, or sequential and may be prepared by emulsion (e.g. e-SBR) or solution polymerization processes (e.g., s-SBR). Additional polymers which may be used include those which are partially or fully functionalized including coupled or star-branched polymers. Additional specific examples of functionalized organic rubbers include polychloroprene, chlorobutyl and bromobutyl rubber as well as brominated isobutylene-co-paramethylstyrene rubber. The preferred organic rubbers are polybutadiene, s-SBR and mixtures thereof.

[0036] Silicone rubbers which are useful as R include organic polysiloxane compositions in which the organic polysiloxane is linear or branched, and optionally may contain, in addition to the hydrocarbon groups, certain reactive groups such as for example, hydroxyl, hydrolyzable groups, alkenyl groups such as vinyl, hydrogen, fluoro, and phenyl. Further examples are given in U.S. Pat. No. 5,009,874, the disclosure of which is hereby expressly incorporated herein by reference.

[0037] Other useful R backbone polymers include acrylonitrile-butadiene rubber (“NBR”), fluorine-containing rubber, epychlorohydrin rubber, butyl rubber, halogenated butyl rubber, brominated isobutylene/p-methylstyrene copolymer rubber, chloroprene rubber, ethylene/acrylate copolymer rubber and epoxidized natural rubber, ethylene/propylene/diene rubber (“EPDM”) and the like.

[0038] The curable polymers of the present invention desirably have a viscosity in the range of about 10 cps to about 1,000,000 cps and more desirably about 1,000 cps to about 100,000 cps.

[0039] The invention further includes alkoxysilyl polymers and polymer compositions, and methods of preparing same through an alkoxy exchange reaction. One method of the present invention includes mixing a composition which includes:

[0040] (a) a polymer within structure I,

[0041] (b) an alkoxysilane in a sufficient amount to permit alkoxy exchange with the alkoxylsilyl groups of structure I, and

[0042] (c) a catalyst.

[0043] This invention includes the composition based on the mixed alkoxysilyl polymer formed from mixing components (a), (b) and (c).

[0044] Component (a) may be chosen from a wide variety of reactive polymers, as set forth herein.

[0045] In structure I, linkage A between the alkoxysilyl group and the polymer backbone R is desirably resistant to common chemicals such as water, solvents, and mild acids and bases. Linkage A is intended to be a stable linkage. Linkage A may optionally be present in cases where R is terminated with appropriate atoms, such as O, to ensure a stable bond with the terminal alkoxysilyl groups. Particularly desirable examples of A include C1-4 alkylene linkages, such as ethylene or propylene. Other particularly desirable examples of A include those having carboxy, carbonate, carbamate, ureido, urethane or sulfonate linkage contained within. When including these groups, A is desirably attached to the terminal silyl group by a branched liner, substituted or unsubstituted, aliphatic, cycloaliphatic or aromatic group in order to improve stability of the spacer. Examples of such A groups include:

[0046] The inventive alkoxy silyl polymers may further include moisture and/or UV/moisture curable polymers, such as silicon polymers (see U.S. Pat. Nos. 4,528,081, 4,675,346, and 4,699,802, the disclosure of each of which being expressly incorporated herein by reference). 4

[0047] wherein R8 is a branched or linear, substituted or unsubstituted aliphatic, cycloaliphatic or aromatic group and P is an integer from 1-4. R8 is desirably methylene, ethylene or propylene.

[0048] Component (b) is an alkoxysilane with the structure of R4nSi(OR1)4−n, where n=0, 1 or 2. The preferred alkoxysilane has n=0 or 1. R4 is a monovalent radical. It includes aryl, alkyl, vinyl, allyl, organofunctional aryl and organofunctional alkyl. Some examples of R4 are 3-aminopropyl, methacryloxypropyl and chloropropyl. R1 is a monovalent radical different from R2, except it may be the same as R2 where A is a carboxy, carbamide, ureido or urethane group. It includes aryl and alkyl. Lower alkyl C1-3, such as ethoxy, is desirable.

[0049] Component (c) may be selected from a variety of known catalysts. For instance, the catalyst may be chosen from transition metal complexes, tin catalysts (such as dialkyl tin dicarboxylates), titanium catalysts (such as metal alkoxide catalysts), bases, acids (such as carboxylic acids), quaternary salts, amines, phosphines, titanates (such as alkyl titanates), and tetraalkylphosphonium salts. Catalysts may be present in amounts of about 0.01 to about 1.0% and desirably about 0.5 to about 0.5% by weight of the total composition. It further includes other conventional catalysts known to be active in reactions of alkoxysilanes. Photoinitiators, such as visible and UV photoinitiators, may also be used.

[0050] According to the method of the present invention, the combination or mixture of the three components, (a), (b) and (c), is aged at ambient temperature or at elevated temperatures. The resulting composition desirably includes polymer and silane containing both R2O and R1O groups. This mixture cures by atmospheric moisture at a different speed from that of the original unaged mixture or the starting materials. The difference in cure speed depends on the nature of the R2O and R1O groups.

[0051] In preparing the reactive polymers of structure I, it is desirable to do so using a catalyst other than a tin-based catalyst. Although tin-based catalysts are useful for moisture curing the formed reactive polymers, when used in the preparation of such reactive polymers residual catalyst from their manufacture may result in poor shelf life and instability in the final curable composition. It has been discovered that a further advantage of the present invention may be captured when catalysts, such as titanium catalysts including titanium tetraisopropoxide, or metal alkoxide catalysts such as sodium methoxide are employed. The aforementioned catalysts are easily quenched subsequent to the formation of the reactive polymer, thereby preventing active residue catalyst from causing premature curing. Additionally, titanium tetraisopropoxide is a particularly useful catalyst for enhancing the rate of the transesterification reaction, though a less efficient condensation catalyst. This allows for the enhanced rate of formation of the mixed alkoxy end groups without sacrificing stability. These catalyst are available commercially from E.I. DuPont de Nemours. Though the catalysts may be used in the range of about 0.01 to about 0.5%, desirably about 0.1 to about 0.3%, the catalysts (which are non tin based ones) have the added advantage of achieving similar cure speeds using smaller amounts of catalyst, e.g., about 0.1 to about 0.2% as compared with 0.5% (tin-based).

[0052] Another method of preparing mixed alkoxysilyl polymers through an alkoxy exchange reaction includes mixing:

[0053] (a) a polymer having at least one alkoxysilyl group,

[0054] (b) an alcohol, and

[0055] (c) a catalyst.

[0056] Component (b) is an alcohol with the structure of R7OH. R7 is a monovalent radical different from R2. It includes aryl and alkyl. Alkyl is preferred.

[0057] According to this method of the present invention, the mixture of the three components, (a), (b) and (c), is aged at ambient temperature or at elevated temperatures. The resulting composition includes catalyst, polymer containing both R2O and R1O groups, and R2OH and R1OH. The alcohols are removed with by evaporation at various temperatures and under various pressures. This resulting composition cures by atmospheric moisture at a different t speed from that of the original mixture. The difference in cure speed depends on the nature of the R2O and R1O groups.

[0058] The invention also provides a method of controlling the cure speed of an alkoxy silyl functional polymer, the steps of which include providing an alkoxy silyl functional polymer having two or more different alkoxy groups; providing a cure catalyst therefor; and exposing the alkoxy silyl functional polymer and the catalyst to conditions sufficient to cure the alkoxy silyl functional polymer. The identity and/or amount of the two or more different alkoxy groups controls the cure speed of the alkoxy silyl functinal polymer having two or more different alkoxy groups thereon.

[0059] The compositions in the present invention can include various other components useful in the manufacturing of moisture curable products. For example, various moisture catalysts, fillers, stabilizers, inhibitors, reactive diluents, viscosity modifiers and the like may be incorporated at useful ranges for their intended purposes.

[0060] It is known that triethoxysilane endcapped polypropylene oxide polymers moisture cure at much slower speeds than trimethoxysilane endcapped counterparts. The present invention seeks to provide a mixture of alkoxysilyl terminated polymers to control and desirably to accelerate the moisture curing capability of the resultant reactive polymers.

EXAMPLES

Example 1

[0061] ViSi(OE)3 was mixed with equal weight of ViSi(OMe)3 or MeOH in the presence of 1% UL-45 (a tin catalyst from Witco). The silane compositions were monitored using 29Si NMR spectroscopy. As seen from data set forth in Table 1, alkoxy exchange occurred.

TABLE 1
Alkoxy Exchange Reactions
Sample		Reaction	Reaction	Mol Percent in Product Mixture
No.	Composition*	time (min.)	(° C.) T	ViSi(OMe)3	ViSi(OMe)2OEt	ViSi(OMe)(OEt)2	ViSi(OEt)3
1	50% ViSi(OEt)3 + 50%	30	RT	54.96	0.95	1.04	43.05
	ViSi(OMe)3
2	50% ViSi(OEt)3 + 50%	60	RT	52.21	3.03	1.94	42.82
	ViSi(OMe)3
3	50% ViSi(OEt)3 + 50%	480	RT	46.79	8.86	6.16	38.19
	ViSi(OMe)3
4	50% ViSi(OEt)3 + 50%	1020	RT	40.99	16.17	9.79	33.05
	ViSi(OMe)3
5	50% ViSi(OEt)3 + 50%	3120	RT	25.6	32.28	18.91	19.21
	ViSi(OMe)3
6	50% ViSi(OEt)3 + 50%	14400	RT	16.73	39.65	32.69	10.92
	ViSi(OMe)3
7	50% ViSi(OEt)3 + 50%	60	80	27.61	32.16	18.81	21.43
	ViSi(OMe)3
8	50% ViSi(OEt)3 + 50%	1440	RT	21.42	24.06	22.31	32.21
	MeOH
9	50% ViSi(OEt)3 + 50%	240	50	26.74	42.88	22.74	7.64
	MeOH
*All samples contained 1% of UL-45 (Sn catalyst).
ViSi(OET)3 is vinyl triethoxy silane.

Example 2

[0062] Polymer A (a triethoxysilylated polypropylene oxide) was prepared by heating a mixture of 400 grams ACCLAIM 4200 (a polypropylene oxide polymer with OH endgroups from Lyondell) with 52 grams SILQUEST A1310 (isocyanatopropyltriethoxy silane from Witco) in the presence of 1.5 grams UL-28 (a Sn catalyst from Witco) at 30-60 C for 3 hours. Sample Nos. 10-12 were prepared in this way with the amounts noted in Table 2a, with Sample No. 10 acting as a control. Mixture of Polymer A with UL-45 (a tin catalyst from Witco) and methoxysilanes were used in several NMR experiments. The results set forth in Table 2b indicate that extensive alkoxy exchange reactions occurred at the 50° C. temperature and over the period of time in days noted.

TABLE 2a
Alkoxy Exchange Reactions
	Sample No./Wt. %
	Component	10	11	12
	Polymer A	99.80	98.71	98.71
	UL-45 (Sn catalyst)	0.20	0.20	0.20
	ViSi(MeO)3		1.10
	Aminopropyltromethoxy			1.10
	Silane
	Total	100.00	100.00	100.00

[0063]

TABLE 2b
Alkoxy Exchange Reactions
	Sample No./relative molar concentration
	10	10	11	11	11	11	12	12
Age at 50° C., days	8	35	9	17	22	44	18	43
(EtO)3Si - capped PPO	1	1	1	1	1	1	1	1
(EtO)2(MeO)Si -			0.202	0.312	0.415	0.407	0.296	0.35
capped PPO
(EtO)(MeO)2Si -			0.054	0.048	0.069	0.063	0.03	0.039
capped PPO
ViSi(MeO)3*			0	0	0	0
ViSi(MeO)2(EtO)			0.088	0.023	0.053	0.053
ViSi(MeO)(EtO)2			0.091	0.064	0.103	0.125
H2NPrSi(MeO)3*							0	0
H2NPrSi(MeO)2(EtO)							0.031	0.092
H2NPrSi(MeO)(EtO)2							0.172	0.393
*consumed during reaction

Example 3

[0064] Polymer B (a triethoxysilylated polypropylene oxide) was prepared by heating a mixture of 450 grams ACCLAIM 12200 (a polypropylene oxide polymer with OH endgroups from Lyondell) with 20.2 grams SILQUEST A1310 (isocyanatopropyltriethoxy silane from Witco) in the presence of 0.1 grams UL-28 (a tin catalyst from Witco) at 30-60° C. for 3 hours.

[0065] Both Polymer A and Polymer B were used to prepare moisture curable compositions (Sample No. 13—Sample No. 22 in Table 3a). Cure speeds of these compositions accelerated with time. The cure acceleration was observed to be faster at 50° C. than at room temperature. Table 3b shows these and other observations of performance.

TABLE 3a
Cure Times of Aged Compositions
(Effects of Alkoxy Exchange Reactions)
	Sample No./Wt. %
Components	13	14	15	16	17	18	19	20	21	22
Polymer B -						99.26	98.77	98.28	98.77	98.28
(EtO)3Si PPO capped
Polymer A -	99.70	94.79	94.97	94.79	93.50
(EtO)3Si PPO capped
Sn catalyst	0.30	0.47	0.28	0.47	0.50	0.50	0.49	0.49	0.49	0.49
ViSi(MeO)3	0.00	4.74	0.00	0.00	1.00		0.49	0.98
ViSi(EtO)3									0.49	0.98
NH2PrSi(MeO)3						0.25	0.25%	0.25	0.25	0.25
MeOH	0.00	0.00	4.75	4.74	5.00

[0066]

TABLE 3b
Cure Times of Aged Compositions
(Effects of Alkoxy Exchange Reactions)
	Sample No.
Physical Properties	13	14	15	16	17	18	19	20	21	22
Aged Temperature, ° C.	RT	RT	RT	RT	RT	RT	RT	RT	RT	RT
Aged Time, days	0	0	0	0	0	0	0	0	0	0
Skin Over Time, min.	480	1440	450	300	50	30	100	200	95	125
Tack Free Time, min.			1200	420	120	195	295	420	320	390
Aged Temperature, ° C.	RT	RT	RT	RT	RT	RT	RT	RT	RT	RT
Aged Time, days	1	1	1	1	1	1	1	1	1	1
Skin Over Time, min.	360	1440	360	120	50	25	88	180	80	100
Tack Free Time, min.	1440				90	180	300	450	330	400
Aged Temperature, ° C.						50	50	50	50	50
Aged Time, days						1	1	1	1	1
Skin Over Time, min.						25	45	65	68	100
Tack Free time, min.						180	190	200	250	400
Aged Temperature, ° C.	RT	RT	RT	RT	RT	RT	RT	RT	RT	RT
Aged Time, days	69	69	69	69	69	3	3	3	3	3
Skin Over Time, min.	300	300	110	27	22	22	60	120	62	120
Tack Free Time, min.			255	60	75	130	140	300	150	280
Aged Temperature, ° C.						50	50	50	50	50
Aged Time, days						3	3	3	3	3
Skin Over Time, min.						20	20	20	60	90
Tack Free Time, min.						120	120	120	160	240

Example 4

[0067] Polymer C (a trimethoxysilylated polypropylene oxide) was prepared by heating a mixture of 914.4 grams ACCLAIM 12200 (a polypropylene oxide polymer with OH endgroups, available commercially from Lyondell) with 50.4 grams SILQUEST A1310 (isocyanatopropyltrimethoxy silane, available commercially from Witco) in the presence of 0.1 grams METATIN 740 (a tin catalyst from Acima) at 70-80° C. for 1 hour.

[0068] Polymer C was used to prepare moisture curable compositions (Sample No. 23—Sample No. 32 in Table 4a). Table 4b shows performance data for these samples.

TABLE 4a
Cure Times of Aged Compositions
(Effect of Different Catalysts on Alkoxy Exchange Reactions)
	Sample No./Wt. %
Components	23	24	25	26	27	28	29	30	31	32
Polymer C - (EtO)3Si PPO	96.5	96.5	96.5	96.5	96.5	96.5	96.5	96.5	96.5	96.5
capped
Ti(OiPr)4 catalyst	0.3	0.3	0.3	0.3
Sn catalyst	0.2	0.2	0.2	0.2	0.5	0.5	0.5	0.5	0.5	0.5
ViSi(OMe)3	2.0	2.0	2.0	2.0	2.0	2.0	2.0	2.0	2.0	2.0
NH2NH2CH2NHPrSi(OMe)3	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0

[0069]

TABLE 4b
Cure Times of Aged Compositions
(Effect of Different Catalysts on Alkoxy Exchange Reactions)
	Sample No./Wt. %
Physical Properties	23	24	25	26	27	28	29	30	31	32
Aged Temperature, ° C.	RT	RT	50	50	RT	50	50	50	50	50
Aged Time, min.	30	1440	120	240	1440	120	240	360	480	1440
Skin Over Time, min.	90	30	30	30	345	315	285	255	195	45

Example 5

[0070] Polymer D (a trimethoxysilylated polypropylene oxide) was prepared by heating a mixture of 920 grams ACCLAIM 12200 (a polypropylene oxide polymer with OH endgroups from Lyondell) with 44.9 grams SILQUEST Y5187 (isocyanatopropyltrimethoxysilane from Witco) in the presence of 0.1 grams METATIN 740 (a tin catalyst from Acima) at 70-80° C. for 1 hour.

[0071] Both Polymer C and Polymer D were used to prepare moisture curable compositions (Sample No. 33—Sample No. 37 in Table 5a). Cure speeds were detected after aging at 70° C. Before curing 0.2% Sn catalyst and 1% NH2CH2CH2NHPrSi(OMe)3 were added at room temperature. Table 5b shows performance data for these samples.

TABLE 5a
Cur Times of Aged Compositions
(Effects of Alkoxy Exchange Reactions)
	Sample No./Wt. %
Components	33	34	35	36	37
Polymer D - (MeO)3Si PPO				98.00	97.80
capped
Polymer C - (EtO)3Si PPO	98.00	97.80	97.80
capped
Ti(OPr)4 catalyst		0.2	0.2		0.2
ViSi(MeO)3	2.00	2.00		2.00	2.00
ViSi(EtO)			2.00

[0072]

TABLE 5b
Cure Times of Aged Compositions
(Effects of Alkoxy Exchange Reactions)
	Sample No.
	Physical Properties	33	34	35	36	37
	Aged Temperature, ° C.	70	70	70	70	70
	Aged Time, min.	30	30	30	30	30
	Skin Over Time, min.	180	20	150	10	10

Claims

1. A curable polymer having the structure:

2. The polymer of claim 1, wherein R is a polymer selected from the group consisting of polyesters, polyethers, polyolefins, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof.

3. The polymer of claim 1, wherein R is polypropylene oxide.

4. The polymer of claim 1, wherein A is a propylene group.

5. The polymer of claim 1, wherein R2 is methyl.

6. A curable composition comprising: (a) a polymer having the structure 6wherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages; A and A′ may be each C1-30 linear or branched, substituted or unsubstituted aliphatic groups or aromatic-containing groups, with or without interruption by a carboxy, carbamate, carbonate, ureido, urethane or sulfonate linkage; n may be 0 or 1; R1 and R2 may be each substituted or unsubstituted C1-12 alkyl or aryl groups; R3 is a C1-12 alkyl, alkenyl, alkoxy, aminoalkyl or aryl group, or a (meth)acryloxyalkyl group. (b) a catalyst.

7. The reaction product of: (a) a polymer having at least one pendant or terminal alkoxysilyl group thereon and being a member selected from the group consisting of polyethers, polyolofins, polyesters, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof; and (b) a catalyst.

8. A method of making an alkoxysilyl endcapped polymer, comprising the steps of: reacting a first reactant having the structure:HO—R—OHwherein R is a hydrocarbon diradical which may include heteroatom and/or silicone-containing groups or linkages, with a second reactant a silyl having one end terminating with an isocyanate group and another end terminating with at least two alkoxy groups attached to a silicon atom thereof, wherein R and the polymeric backbone of the second reactant are selected from the group consisting of polyesters, polyethers, polyolefins, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof, and providing for reaction as a third reactant a methoxy silane in amounts and for a time sufficient to achieve alkoxy exchange with said alkoxysilyl endcapped polymer.

9. The polymer of claim 8, wherein R is an alkylene oxide.

10. A composition having controlled moisture cure speed comprising the reaction product of: (a) an alkoxysilyl endcapped polymer having a backbone selected from the group consisting of polyesters, polyethers, polyolefins, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof; (b) an alkoxysilane present in sufficient amounts to permit alkoxy exchange with the alkoxysilyl endcapped polymer; and (c) a catalyst.

11. The method of claim 8, further including the step of compounding the resultant reaction product with a methoxy silane in amounts and for a time sufficient to allow for alkoxy exchange to take place.

12. The composition of claim 6, wherein the catalyst is a transition metal complex.

13. The composition of claim 6, wherein the catalyst is selected from the group consisting of tin catalysts, titanium catalysts, metal alkoxide catalysts and combinations thereof.

14. The composition of claim 6, wherein the catalyst is selected from the group consisting of bases, acids, and quaternary salts.

15. The composition of claim 6, wherein the catalyst is selected from the group consisting of amines, phosphines, dialkyl tin dicarboxylates, the titanates, tetraalkylphosphonium salts, metal oxides, and carboxylic acids.

16. The method of enhancing the rate of transesterification comprising permitting first and second reactants, each having a different alkoxy group pendant thereon to undergo transesterification in the presence of a titanium or metal alkoxide catalyst.

17. A composition having controlled moisture cure speed comprising the reaction product of: (a) an alkoxysilyl endcapped polymer having a backbone selected from the group consisting of polyesters, polyethers, polyolefins, polyurethanes, polysiloxanes, poly(meth)acrylates, polyepoxides and combinations thereof; (b) an alcohol present in sufficient amounts to permit alkoxy exchange with the alkoxysilyl endcapped polymer; and (c) a catalyst.

18. A method of controlling the cure speed of an alkoxy silyl functional polymer, comprising the steps of: providing an alkoxy silyl functional polymer having two or more different alkoxy groups; providing a cure catalyst therefor; and exposing the alkoxy silyl functional polymer and the catalyst to conditions sufficient to cure the alkoxy silyl functional polymer, wherein the identity and/or amount of the two or more different alkoxy groups controls the cure speed of the alkoxy silyl functional polymer having two or more different alkoxy groups thereon.