Silylated polyurethanes and methods for preparing thereof

Abstract

The invention relates to a silylated polyurethane obtainable by reacting: d) at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol; e) at least one polyisocyanate, preferably diisocyanate; and f) at least one tertiary hydroxyl functional alkoxysilane of the general formula (I) ##STR00001##
wherein R.sup.1 is selected from the group consisting of hydrogen and a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.2 and R.sup.3 are same or different and are, independent from one another, selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.4 is selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.5 is selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.6 and R.sup.7 are same or different and are, independent from one another, selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; and n is 1, 2 or 3, a method for preparing thereof, a curable composition comprising the thereby obtained silylated polyurethane, and its use.

Claims

1. A silylated polyurethane obtained by reacting: a) at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol; b) at least one polyisocyanate; and c) at least one tertiary hydroxyl functional alkoxysilane of the general formula (I) ##STR00010## wherein R.sup.1 is selected from the group consisting of hydrogen and a linear or branched, substituted or unsubstituted, hydrocarbon residue having 1 to 20 carbon atoms; R.sup.2 and R.sup.3 are, independent from one another, selected from a linear or branched, substituted or unsubstituted, hydrocarbon residue having 1 to 20 carbon atoms; R.sup.4 is selected from a linear or branched, substituted or unsubstituted, hydrocarbon residue having 1 to 20 carbon atoms; R.sup.5 is selected from a linear or branched, substituted or unsubstituted, hydrocarbon residue having 1 to 20 carbon atoms; R.sup.6 and R.sup.7 are, independent from one another, selected from a linear or branched, substituted or unsubstituted, hydrocarbon residue having 1 to 20 carbon atoms; n is 1, 2 or 3; and wherein the tertiary hydroxyl functional alkoxysilane of the general formula (I) is obtained by reacting at least one di-substituted lactone compound and at least one aminosilane having at least one primary or secondary amino group.

2. The silylated polyurethane according to claim 1, wherein at least one compound that is monofunctional to isocyanates, selected from the group consisting of monoalcohols, monomercaptans, monoamines, and mixtures thereof, and/or monoisocyanate is added in the reacting of the silylated polyurethane.

3. The silylated polyurethane according to claim 1, wherein the polyol is a polyether polyol.

4. The silylated polyurethane according to claim 1, wherein R.sup.1 is selected from hydrogen or a C.sub.1-C.sub.8 alkyl residue.

5. The silylated polyurethane according to claim 1, wherein R.sup.2 and R.sup.3 are independent from one another selected from a linear or branched, substituted or unsubstituted, C.sub.1-C.sub.20 alkyl or C.sub.6-C.sub.18 aryl residue; and n is 2 or 3, 3.

6. The silylated polyurethane according to claim 1, wherein R.sup.4 and R.sup.5 are independent from one another selected from a linear or branched, substituted or unsubstituted, C.sub.1-C.sub.20 alkylene.

7. The silylated polyurethane according to claim 1, wherein R.sup.6 and R.sup.7 are independent from one another selected from a linear or branched, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkenyl, C.sub.1-C.sub.20 alkynyl, or C.sub.6-C.sub.18 aryl residue.

8. The silylated polyurethane according to claim 1, wherein the di-substituted lactone has the general formula (II) ##STR00011## and the aminosilane has the general formula (III) ##STR00012## wherein the R.sup.1 to R.sup.7 and n are the same as defined above for the general formula (I).

9. The silylated polyurethane according to claim 1, wherein the silylated polyurethane is obtained by: (a) reacting the at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol with the at least one polyisocyanate, at a stoichiometric excess of the NCO group of the polyisocyanate(s) with respect to the OH group of the polyol(s) to form a NCO-terminated polyurethane prepolymer; and (b) reacting said NCO-terminated polyurethane prepolymer with the at least one tertiary hydroxyl functional alkoxysilane of the general formula (I).

10. The silylated polyurethane according to claim 1, wherein the silylated polyurethane is obtained by: (a) mixing the at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol and the at least one tertiary hydroxyl functional alkoxysilane of the general formula (I), at a stoichiometric excess of the OH group of the tertiary hydroxyl functional alkoxysilane(s) of the general formula (I) with respect to the OH group of the polyol(s); and (b) reacting the mixture obtained in step (a) with at least one polyisocyanate, at a stoichiometric excess of the NCO group of the polyisocyanate(s) with respect to the OH group of the polyol(s) and the tertiary hydroxyl functional alkoxysilane(s) of the general formula (I).

11. A method for preparing a silylated polyurethane, comprising: providing (a) at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol; providing (b) at least one polyisocyanate, diisocyanate; and providing (c) at least one tertiary hydroxyl functional alkoxysilane of the general formula (I) ##STR00013## wherein R.sup.1 is selected from the group consisting of hydrogen and a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.2 and R.sup.3 are same or different and are, independent from one another, selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.4 is selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.5 is selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; R.sup.6 and R.sup.7 are same or different and are, independent from one another, selected from a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 20 carbon atoms; and n is 1, 2 or 3; wherein the tertiary hydroxyl functional alkoxysilane of the general formula (I) is obtained by reacting at least one di-substituted lactone compound and at least one aminosilane having at least one primary or secondary amino group; and reacting the (a) at least one polyol having a number average molecular weight of from 1000 to 50,000 g/mol; and (b) the at least one polyisocyanate; and (c) the at least one tertiary hydroxyl functional alkoxysilane of the general formula (I).

12. A curable composition comprising the silylated polyurethane according to claim 1.

13. An adhesive, sealant, spray foam and/or coating comprising the silylated polyurethane according to claim 1.

Description

EXAMPLES

(1) Examples 1 and 2: 140 g (12.5 mmol) of polypropylene glycol of approximate molecular weight 12 000 g/mol (OH no.=10 mg KOH/g) was poured in a 250 ml three neck flask and dried under vacuum at 80° C. for 1 h. After the vacuum was released and replaced with argon, 0.19 g (0.25 mmol) of DOTL catalyst and 5.83 g (26.3 mmol) of isophorone diisocyanate (IPDI) was added and the reaction mixture was stirred for 1 hour at the same temperature. In the second step 26.3 mmol of hydroxyl functional silanes listed in the Table 1 was added and kept stirring at 80° C. for 3 hours. After the described procedure the sample was collected and analyzed in IR spectrometer. No bands for NCO groups were observed, meaning that all of the NCO groups were reacted.

Comparative Example 1

(2) The procedure described in Examples 1 and 2 was repeated. In the second step 26.3 mmol of (3-aminopropyl) trimethoxysilane was added instead of the hydroxyl functional silane. After the described procedure the sample was collected and analyzed in IR spectrometer. No bands for NCO groups were observed, meaning that all of the NCO groups were reacted.

(3) Examples 3 and 4: 140 g (12.5 mmol) of polypropylene glycol of approximate molecular weight 12 000 g/mol (OH no.=10 mg KOH/g) was poured in a 250 ml three neck flask and dried under vacuum at 80° C. for 1 h. After the vacuum was released and replaced with argon, 0.19 g (0.25 mmol) of DOTL catalyst and 26.3 mmol of hydroxyl functional silane listed in the Table 1 were added and homogenously mixed. Afterwards 5.83 g (26.3 mmol) of isophorone diisocyanate (IPDI) was added and the reaction mixture was stirred for 3 hours at the same temperature. After the described procedure the sample was collected and analyzed in IR spectrometer. No bands for NCO groups were observed, meaning that all of the NCO groups were reacted.

Comparative Example 2

(4) The procedure described in Examples 3 and 4 was repeated. In the first step 26.3 mmol of (3-aminopropyl)trimethoxysilane was added instead of the hydroxyl functional silane. Highly viscous turbid liquid was formed, which is not suitable for further application as a sealant or adhesive. After the described procedure the sample was collected and analyzed in IR spectrometer. No bands for NCO groups were observed, meaning that all of the NCO groups were reacted.

(5) The viscosity of the obtained prepolymers after the endcapping was measured at 25° C. by Anton Paar MCR 302 Rheometer in neat conditions using PP25/TG stirring plate.

(6) TABLE-US-00001 TABLE 1 Viscosity of the prepolymers prepared according to the Examples 1 to 4 and Comparative Examples 1 and 2 Viscosity End-capper (Pas) Example 1 4-hydroxy-4-methyl-N-(3- 164 (trimethoxysilyl)propyl)decanamide Example 2 4-hydroxy-4-methyl-N-(3- 189 (trimethoxysilyl)propyl)-7-decenamide Comp. Example 1 (3-aminopropyl) trimethoxysilane 624 Example 3 4-hydroxy-4-methyl-N-(3- 287 (trimethoxysilyl)propyl)decanamide Example 4 4-hydroxy-4-methyl-N-(3- 271 (trimethoxysilyl)propyl)-7-decenamide Comp. Example 2 (3-aminopropyl) trimethoxysilane 1183