Moisture curable high strength, flexible RTV organic copolymer compositions and methods of preparation
View Patent ↗Flexible, moisture curing ABA triblock copolymers are prepared from poly(alkylene oxide) diols as the B segment and polyester diols as the A block. This backbone is end-capped with siloxy end groups to obtain RTV moisture curing triblocks having high strength and flexibility.
1. A moisture curable composition comprising a polymer having the formula:
wherein ABA is a polyester/polyether/polyester triblock copolymer, wherein the polyester (A) blocks comprise a poly(diethylene glycol o-phthalate) block;
R is C 1-6 alkyl group or C 6 aryl group, which may optionally be substituted by halo;
R 1 is C 1-6 alkyl group;
m is 0–2;
X is independently at each occurrence a urethane linkage
or a urea linkage
wherein R 3 is alkylene; R 4 is alkyl, alkaryl or aryalkyl; and
p is 0 or 1.
2. The composition of claim 1 , wherein the polyether (B) block comprises a poly(propylene oxide) block.
3. The composition of claim 1 , wherein the polyether (B) block comprises a poly(tetramethylene ether) block.
4. The composition of claim 1 , wherein the polyether (B) block has a molecular weight of about 2,000 to about 4,000.
5. The composition of claim 1 , wherein the polyester (A) block has a molecular weight of about 500 to about 1,000.
6. The composition of claim 1 , further including a moisture cure catalyst.
7. The composition of claim 6 , wherein the moisture cure catalyst is selected from the group consisting of amines, organometallic compounds, phosphines, imidazoles, and combinations thereof.
8. The composition of claim 1 , further including one or more fillers.
9. The composition of claim 8 , wherein a filler is selected from the group consisting of alkali metal carbonates, carbon black, fumed silica, precipitated silica, sulfates, metal silicates, metal oxides and combinations thereof.
10. A moisture curable composition comprising:
(a) a polymer having the formula:
wherein ABA is a polyester/polyether/polyester triblock copolymer;
R is C 1-6 alkyl group or C 6 aryl group, which may optionally be substituted by halo;
R 1 is C 1-6 alkyl group;
m is 0–2;
X is independently at each occurrence a urethane linkage
or a urea linkage
wherein R 3 is alkylene; R 4 is alkyl, aryl, alkaryl or aryalkyl; and p 1 is 0 or 1; and
(b) a moisture cure catalyst wherein the moisture curing catalyst is selected from the group consisting of 1,8-diazabicyclo[5.4.0] undec-7-ene, dimethylaminopyridine and combinations thereof.
11. A method of preparing a moisture curing composition comprising the steps of:
(a) reacting a NCO capped polyether with a polyester diol having each of two ends terminated with a hydroxy group, wherein the molar ratio of NCO capped polyester prepolymer to polyester diol being equal to or less than 1:2 to form a block copolymer represented by the structure:
HO-A-B-A-OH II
wherein B is a polyether block and A is a polyester block; and
(b)(i) further reacting the structure formed in step (a) with a molar excess of an isocyanatoalkyl polyalkoxysilane to form a moisture curable composition; or
(b)(ii) further reacting the hydroxy terminated polyester/polyether/polyester triblock copolymer (II) with a diisocyanate to provide NCO capping at each end of the triblock copolymer; and further reacting the product of this reaction with an aminoalkylenepolyalkoxysilane to form a moisture curable composition.
12. The method of claim 11 , further including the steps of forming the NCO capped polyether comprising reacting a polyether, functionally terminated with either hydroxy groups or amino groups, with a diisocyanate, wherein the molar ratio of diisocyanate functionally terminated polyether is at least about 1:2.
13. The method of claim 11 , wherein the polyether (B) block has a molecular weight of from about 2,000 to about 4,000.
14. The method of claim 11 , wherein the polyester (A) block has a molecular weight of about 500 to about 1,000.
15. The method of claim 11 , wherein the polyether (B) block is a poly(propylene oxide) block.
16. The method of claim 11 , wherein the polyether (B) block is a poly(tetramethylene ether) block.
17. The method of claim 11 , wherein the isocyanatoalkyl polyalkoxy silane is selected from the group consisting of isocyanatopropyltrimethoxy silane, isocyanatoethyltrimethoxy silane, and isocyanatomethyltrimethoxy silane.
18. The reaction product of
(a) a composition comprising a compound having the formula:
wherein ABA is a polyester/polyether/polyester triblock copolymer, wherein the polyester (A) blocks comprise a poly(diethylene glycol o-phthalate) block;
R is C 1-6 alkyl group or C 6 group, which may optionally be substituted by a halo;
R 1 is C 1-6 alkyl group;
m is 0–2;
X is independently at each occurrence
or
wherein R 3 is alkylene; R 4 is alkyl, aryl, alkaryl or aryalkyl; and
p is 0 or 1; and
(b) a moisture cure catalyst.
19. The reaction product of
(a) a composition comprising a compound having the formula:
wherein ABA is a polyester/polyether/polyester triblock copolymer;
R is C 1-6 alkyl group or C 6 group, which may optionally be substituted by a halo;
R 1 is C 1-6 alkyl group;
m is 0–2;
X is independently at each occurrence
or
wherein R 3 is alkylene; R 4 is alkyl, aryl, alkaryl or aryalkyl; and
p is 0 or 1; and
(b) a moisture cure catalyst, wherein the moisture curing catalyst is selected from the group consisting of 1,8-diazabicyclo[5.4.0] undec-7-ene, dimethylaminopyridine and combinations thereof.