USE OF AN ORAGANOCARBONATE-MODIFIED PREPOLYMER AS REACTANT FOR PREPARATION OF ISOCYANATE-FREE AND ISOTHIOCYANATE-FREE ALKOXYSILANE POLYMERS

Abstract

The use of an organocarbonate-modified prepolymer having at least an average of 1.5 carbonate, thiocarbonate, carbamate or thiocarbamate groups bonded directly to the polymer backbone each via an oxygen atom, where each of these oxygen atoms has its origin in the reaction of a primary, secondary or tertiary hydroxyl group of the polymer backbone and a reactive compound selected from the group consisting of a diorganocarbonate, a diorganothiocarbonate, a cyclic carbonate, a cyclic thiocarbonate, an N,N-diheterocyclourea derivative and an N,N-diheterocyclothiourea derivative. Also, the preparation of the alkoxysilane polymers.

Claims

1. The use of a prepolymer having at least on average 1.5 carbonate groups of the formulae (I) and (II) or thiocarbonate groups of the formulae (Ia) and (IIa), carbamate groups of the formulae (XI) and (XII) or thiocarbamate groups of the formulae (XIa) and (XIIa) ##STR00017## in which R.sup.1 and R.sup.2 independently of one another are linear or branched C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 acyl, C.sub.3 to C.sub.8 cycloaliphatic, C.sub.6 to C.sub.10 aryl or imide radicals or C.sub.3 to C.sub.6 alcohols, R.sup.11 and R.sup.12 and also R.sup.13 and R.sup.14 in each case together form heterocyclic ring systems which may be aromatic or nonaromatic and are independent of one another, and where these ring systems may contain further heteroatoms selected from the group of oxygen, nitrogen, and sulfur or may contain functional groups selected from the group of acyl and thioacyl, as a reactant for the isocyanate-free and isothiocyanate-free preparation of alkoxysilane polymers, whose alkoxysilane groups are bonded via carbamate groups, thiocarbonate groups or thiocarbamate groups to the polymer backbone, where the at least on average 1.5 carbonate, thiocarbonate, carbamate or thiocarbamate groups are bonded directly via one oxygen atom each to the polymer backbone, this one oxygen atom each having its origin in the reaction of a primary, secondary or tertiary hydroxyl group of the polymer backbone and a reactive compound selected from the group consisting of a diorganocarbonate, a diorganothiocarbonate, a cyclic carbonate, a cyclic thiocarbonate, an N,N-diheterocyclourea derivative, and an N,N-diheterocyclothiourea derivative.

2. The use as claimed in claim 1, where the prepolymer has at least on average 1.5 carbonate groups ##STR00018## in which R.sup.1 and R.sup.2 independently of one another are linear or branched C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 acyl, C.sub.3 to C.sub.8 cycloaliphatic, C.sub.6 to C.sub.10 aryl or imide radicals or C.sub.3 to C.sub.6 alcohols, as a reactant for the isocyanate-free and isothiocyanate-free preparation of alkoxysilane polymers whose alkoxysilane groups are bonded via carbamate groups or thiocarbonate groups to the polymer backbone, where the at least on average 1.5 carbonate groups are bonded directly via one oxygen atom each to the polymer backbone, this one oxygen atom each having its origin in the transesterification reaction of a primary, secondary or tertiary hydroxyl group of the polymer backbone and a diorganocarbonate or a cyclic carbonate.

3. The use as claimed in claim 1, where the polymer backbone is linear or branched and is selected from the group consisting of polyethers, polyolefins, polyesters, polycarbonates, polyacrylates, polysulfides, polysiloxanes, polyacetals, and copolymers thereof.

4. The use as claimed in claim 1, where the N,N-diheterocyclourea derivative is selected from the group consisting of 1,1-carbonyldiimidazole (CDI), 1,1-carbonyldibenzimidazole, 1,1 -carbonyldi(1,2,4)-triazole (CDT), 1,1-carbonylbis(2-methylimidazole), 1,1-carbonyldibenzotriazole, and carbonylbiscaprolactam (CBC).

5. The use as claimed in claim 1, where the at least on average 1.5 carbonate, thiocarbonate, carbamate or thiocarbamate groups of the prepolymer of the general formulae III, Ma, XIII or XIIIa ##STR00019## where [A] is the polymer backbone and R.sub.1, R.sub.2, R.sub.11, R.sub.12, R.sub.13 and R.sub.14 have the same definition as in claim 1, are arranged at the terminal ends of the polymer backbone.

6. The use as claimed in claim 1, where R.sup.1 and R.sup.2 are identical and preferably are methyl, ethyl, phenyl, succinimide or maleimide, more preferably methyl or phenyl.

7. The use as claimed in claim 1, where (a) at least part of the polymer backbone is linear and preferably the entire polymer backbone is linear, or (b) at least part of the polymer backbone is branched and possesses one or more branchings.

8. use as claimed in claim 7, where the one or more branchings may comprise one or more ether, ester, carbonate, acrylate or sulfide groups and may optionally have a terminal group of the formulae (IV) or (XIV) ##STR00020## where R.sub.3 has the same definition as R.sub.1 and R.sub.2, and R.sup.15 and R.sup.16 in each case together form a heterocyclic ring system having the same definition as the heterocyclic ring systems formed respectively from R.sup.11 and R.sup.12 and from R.sup.13 and R.sup.14.

9. The use as claimed in claim 8, where each branching has a terminal group of the formula IV or of the formula XIV.

10. The use as claimed in claim 1, where the polymer backbone is selected from the group consisting of polyethers, polyesters, polycarbonates, polysulfides, polysiloxanes or polyacrylates and copolymers thereof.

11. The use as claimed in claim 1, where the polymer backbone is a polyether, preferably a polyethylene glycol or a polypropylene glycol, more preferably a linear or a multiarm polypropylene glycol.

12. The use as claimed in claim 1, wherein the prepolymer is selected from the group consisting of ##STR00021## ##STR00022## ##STR00023## n is the number of monomer units, and the molecular weight is between 1000 and 100 000 g/mol, preferably between 5000 and 50 000 g/mol, and R.sup.1, R.sup.2, R.sup.3, and R.sup.3 independently of one another are linear or branched C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 acyl, C.sub.3 to C.sub.8 cycloaliphatic, C.sub.6 to C.sub.10 aryl or imide radicals, with R.sup.1, R.sup.2, R.sup.3, and R.sup.3 preferably being all identical and more preferably all being methyl, ethyl or phenyl, and R.sup.11 and R.sup.12, R.sup.13 and R.sup.14, R.sup.15 and R.sup.16 and also R.sup.15 and R.sup.16 in each case together form heterocyclic ring systems which may be aromatic or nonaromatic and are independent of one another and where these ring systems may contain further heteroatoms selected from the group of oxygen, nitrogen, and sulfur or may contain functional groups selected from the group of acyl and thioacyl.

13. A process for preparing an alkoxysilane polymer by reacting the prepolymer as set forth in claim 1 (A) with an aminoalkoxysilane or a mercaptoalkoxysilane, optionally in the presence of a catalyst, or (B) with a diamine, a triamine, a dithiol or a trithiol to give a modified prepolymer and subsequently carrying out reaction with an alkoxysilane compound containing an epoxide group, where an alkoxysilane polymer is formed.

14. The process as claimed in claim 13, wherein, before the reaction steps according to variant (A) or variant (B), the prepolymer is reacted with an alcohol or with an activated alcohol, the activated alcohol preferably being glycerol carbonate.

15. The process as claimed in claim 13, wherein the aminoalkoxysilane in variant (A) is selected from the group of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropylmethyldimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, N-ethylaminoisobutyltrimethoxysilane, N-ethylaminoisobutylmethyldimethoxysilane, 3-piperazinopropyltrimethoxysilane, 3-piperazinopropylmethyldimethoxysilane, 3-piperazinopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxy-silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and an equimolar reaction product of piperazine and glycidoxypropyltrimethoxysilane, and the mercaptoalkoxysilane is selected from the group of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

16. The use of a composition comprising an alkoxysilane polymer prepared by a process as claimed in claim 13 as a moisture-curing sealant or adhesive, wherein the alkoxysilane polymer is isocyanate-free and/or isothiocyanate-free.

Description

EXAMPLE 1

Methyl Carbonate-Terminated Polyether with Aminosilane

[0119] 95.7 g of polyether diol (Desmophen 4028BD from Covestro) are refluxed at 120 C. for 18 h with 17.3 g of dimethyl carbonate (4:1 based on OH groups) and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The methanol formed and the excess of dimethyl carbonate can be subsequently distilled off under reduced pressure. The product obtained is methyl carbonate-terminated polyether.

##STR00015##

[0120] 50 g of the methyl carbonate-terminated polymer are reacted with 4.3 g of 3-aminopropyltrimethoxysilane and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) at 60 C. for 24 h. The methanol formed is removed by distillation. The product obtained is trimethoxysilane-terminated polyether. The trimethoxysilane groups are joined to the polyether via a urethane bond.

##STR00016##

[0121] The polymer can be used for producing moisture-curing adhesives, sealants, and coating materials on the basis of silane-terminated polymers.

EXAMPLE 2

Methyl Carbonate-Terminated Polyether with a Diamine, Subsequent Reaction with Epoxysilane

[0122] 95.7 g of polyether diol (Desmophen 4028BD from Covestro) are refluxed at 120 C. for 18 h with 17.3 g of dimethyl carbonate (4:1 based on OH groups) and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The methanol formed and the excess of dimethyl carbonate can be subsequently distilled off under reduced pressure. The product obtained is methyl carbonate-terminated polyether. 50 g of the methyl carbonate-terminated polymer are reacted with 2.84 g of hexamethylenediamine and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) at 60 C. for 24 h. The methanol formed is removed by distillation. The product obtained is an amine-terminated polyether. This polyether can be reacted with an alkoxysilane compound having an epoxide group, as for example (3-glycidyloxypropyl)trimethoxysilane, to form a trimethoxysilane-terminated polyether. Such reactions are described in detail in European patent application EP-A-2 341 116, hereby referenced.

[0123] The resulting polymer can be used for producing moisture-curing adhesives, sealants, and coating materials on the basis of silane-terminated polymers.

EXAMPLE 3

Curing of a Methyl Carbonate-Terminated Polyether to form an Isocyanate-Free Polyurethane

[0124] 95.7 g of polyether diol (Desmophen 4028BD from Covestro) are refluxed at 120 C. for 18 h with 17.3 g of dimethyl carbonate (4:1 based on OH groups) and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The methanol formed and the excess of dimethyl carbonate can be subsequently distilled off under reduced pressure. The product obtained is methyl carbonate-terminated polyether.

[0125] 50 g of the methyl carbonate-terminated polymer are mixed with 1.42 g of hexamethylenediamine and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), optionally in a solvent or in water, in the presence of auxiliaries such as stabilizers and emulsifiers at 90 C. for 24 h. The molar mass of the polyether-polyurethane can be influenced by the auxiliaries and reaction conditions. The resulting dispersion can subsequently be used, for example, for polyurethane dispersion-based adhesives.

EXAMPLE 4

Imidazole Carbamate-Terminated Polyether with Aminosilane

[0126] 95.5 g of polyether diol (Desmophen 4028BD from Covestro) are stirred under nitrogen at 60 C. for 12 h with 7.76 g of 1,1-carbonyldiimidazole (CDI) (1:1 based on OH groups). The product obtained is imidazole carbamate-terminated polyether.

[0127] 50 g of the imidazole carbamate-terminated polymer are reacted with 4.3 g of 3-aminopropyltrimethoxysilane at 60 C. for 24 h. The product obtained is trimethoxysilane-terminated polyether. The trimethoxysilane groups are joined to the polyether via a urethane bond.

[0128] The resulting trimethoxysilane-terminated polymer can be catalyzed without tin and crosslinks following addition of 0.2% of 1,8-diazabicyclo[5.4.0]undec-7-ene and 1% of 3-aminopropyltrimethoxysilane, under atmosphere moisture, to form an elastic material having a Shore A hardness of 41 after 7 days.