METHOD FOR PRODUCING SILANE-MODIFIED POLYMERS

Abstract

A method for producing an alkoxysilane polymer via a carbamate, thiocarbonate or carbonate-terminated prepolymer (IIIa) or (IIIb) includes reaction of a polymer backbone of formula (I) terminated with at least two amino, mercapto or hydroxyl groups and with a chloroformate of formula (IIa) or a pyrocarbonate of formula (Ilb) (I) (IIa) (IIb) (IIIa) (IIIb), wherein R.sup.1 and R.sup.3 represent a linear or branched, saturated or unsaturated alkyl or alkenyl group with 1 to 10 carbon atoms or a mono- or polycyclic aliphatic or aromatic ring system with 5 to 18 carbon atoms in the ring system, which is optionally substituted by one or more groups R.sup.2, X is oxygen or sulphur, n is 0 for a linear or branched, saturated or unsaturated alkyl or alkenyl group and is 0.1 or 2 for a mono- or polycyclic aliphatic or aromatic ring system, and A represents a polymer backbone.

Claims

1. A method for producing an alkoxysilane polymer via a carbamate-, thiocarbonate- or carbonate-terminated prepolymer (IIIa) or (IIIb), wherein the production of the carbamate-, thiocarbonate- or carbonate-terminated prepolymer comprises a reaction of a polymer backbone of formula (I), terminated with at least two amino, mercapto or hydroxyl groups, with a chloroformate of formula (IIa) or a pyrocarbonate of formula (Iib) ##STR00020## wherein R.sub.1 and R.sub.3 are a linear or branched, saturated or unsaturated alkyl or alkenyl group having 1 to 10 carbon atoms or a mono- or polycyclic aliphatic or aromatic ring system having 5 to 18 carbon atoms in the ring system, which is optionally substituted by one or more radicals R.sup.2, wherein R.sup.2 is selected from the group consisting of a linear or branched, saturated or unsaturated alkyl or alkenyl group having 1 to 10 carbon atoms, a nitro group, a carboxylic ester group, a carboxylic acid group, a sulfone group and a halogen group X is oxygen, nitrogen, or 4ulphur y is 1 when X is oxygen or 4ulphur and 1 or 2 when X is nitrogen, n is 0 in the case of a linear or branched, saturated or unsaturated alkyl or alkenyl group and is 0, 1 or 2 in the case of a mono- or polycyclic aliphatic or aromatic ring system and A is a polymer backbone.

2. The method as claimed in claim 1, wherein the reaction is carried out with a chloroformate of formula (Iia).

3. The method as claimed in claim 1, wherein the reaction is carried out in the absence of a first catalyst (I).

4. The method as claimed in claim 1, wherein R.sup.1 is a mono- or polycyclic aromatic ring system having 6 to 18 carbon atoms in the ring system, selected from the group consisting of phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl and 9-phenanthryl and n is 0 or 1.

5. The method as claimed in claim 1, wherein R.sup.1 is an alkyl group selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl.

6. The method as claimed in claim 1, wherein the polymer backbone of formula (I) has exactly two amino, mercapto or hydroxyl groups.

7. The method as claimed in claim 1, wherein the polymer backbone of formula (I) has more than two amino, mercapto or hydroxyl groups.

8. The method as claimed in claim 7, wherein essentially each monomer unit of the polymer backbone has a side chain with an amino, mercapto or hydroxyl group.

9. The method as claimed in claim 1, wherein the polymer backbone A is selected from the group consisting of polyethers, polyalcohols, polyolefins, polyesters, polycarbonates, polyamines, polyamides, polyacrylates, polysulfides, polysiloxanes, polyacetals and copolymers thereof.

10. The method as claimed in claim 9, wherein the polymer backbone A is polypropylene glycol or a polyester.

11. The method as claimed in claim 1, wherein the prepolymer (III) is reacted in a further step with (A) an aminoalkoxysilane or a mercaptoalkoxysilane, optionally in the presence of a second catalyst (II) or (B) a diamine, a triamine, a dithiol or a trithiol to give a modified prepolymer and is then reacted with an alkoxysilane compound having an epoxy group, wherein an alkoxysilane polymer is formed.

12. The method as claimed in claim 11, in which the prepolymer is reacted with an alcohol or an activated alcohol prior to the reaction steps according to variant (A) or variant (B).

13. The method as claimed in claim 11, in which in variant (A) the aminoalkoxysilane is selected from the group comprising 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-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and an equimolar reaction product of piperazine and glycidoxypropyltrimethoxysilane and the mercaptoalkoxysilane is selected from the group comprising 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

Description

EXAMPLES

[0058] The invention is further illustrated by the following examples.

Example 1: Carbonate-Terminated Polyether with Aminosilane

[0059] 95.7 g (0.024 mol) of polyether diol (Desmophen 4028BD from Covestro) are dissolved in 100 ml of toluene at room temperature (25° C.). Then 6.1 g (0.06 mol) of triethylamine are added. The solution is homogeneous after a brief time and is colorless and clear. 7.74 g (0.049 mol) of phenyl chloroformate, pre-dissolved in 12 ml of toluene, are uniformly added dropwise to the reaction solution over a period of 45-75 minutes. The reaction mixture is further stirred for at least 8 hours. The reaction mixture is then cooled down to ca. 8° C. The resulting precipitate of triethylamine hydrochloride is filtered off and washed off with a little toluene. The solvent is then removed under reduced pressure. A carbonate-terminated polyether is obtained as product in high yield.

##STR00010##

[0060] 50 g (0.012 mol) of the phenyl carbonate-terminated polymer are left to react with 4.30 g (0.024 mol) of 3-aminopropyltrimethoxysilane (Evonik) for at least 12 h at 25° C. The phenol formed remains behind in dissolved form in the colorless to slightly yellowish, clear reaction mixture. Trimethoxysilane-terminated polyether is obtained as product. The trimethoxysilane groups are attached to the polyether via a urethane bond.

##STR00011##

[0061] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.

Example 2: Carbonate-Terminated Polyether with Aminosilane

[0062] 50 g (0.012 mol) of the phenyl carbonate-terminated polymer, prepared analogously to Example 1, are left to react with 6.26 g (0.024 mol) of piperazinylmethylmethyldiethoxysilane (SiSiB® SILANES) for at least 12 hours at 25° C. The phenol formed remains in dissolved form in the colorless to pale yellowish, clear reaction mixture. Diethoxysilane-terminated polyether is obtained as product. The diethoxysilane groups are attached to the polyether via a urethane bond.

##STR00012##

[0063] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.

Example 3: Carbonate-Terminated Polyether with Aminosilane

[0064] 50 g (0.012 mol) of the phenyl carbonate-terminated polymer, prepared analogously to Example 1, are left to react with 6.26 g (0.024 mol) of [3-(1-piperazinyl) propyl]trimethoxysilane at 25° C. for at least 12 hours. The phenol formed remains behind in dissolved form in the colorless to slightly yellowish, clear reaction mixture. Trimethoxysilane-terminated polyether is obtained as product. The trimethoxysilane groups are attached to the polyether via a urethane bond.

##STR00013##

[0065] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.

Example 4: Methyl Carbonate Terminated Polyether with Aminosilane

[0066] 95.7 g (0.024 mol) of polyether diol (Desmophen 4028BD from Covestro) are predried at 80° C. for one hour under reduced pressure. It is then cooled to room temperature. 7.2 g (0.054 mol) of dimethyl dicarbonate (Merck) are added at room temperature. 0.1 g of lanthanum triflate are added to the reaction mixture as catalyst. The reaction mixture is left to react overnight under reduced pressure in order to remove the methanol and carbon dioxide formed from the reaction mixture. The product obtained is methyl carbonate-terminated polyether in high yield.

##STR00014##

[0067] 50 g (0.012 mol) of the carbonate-terminated polymer are reacted with 4.30 g (0.024 mol) of 3-aminopropyltrimethoxysilane (Evonik) and 0.1 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (Sigma-Aldrich) at 60° C. for 24 h. The methanol formed is distilled off. Trimethoxysilane-terminated polyether is obtained as product. The trimethoxysilane groups are attached to the polyether via a urethane bond.

##STR00015##

[0068] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.

Example 6: Carbonate-Terminated Polyester with Aminosilane

[0069] 100 g (0.016 mol) of polyester diol (polyol P-6010 from Kuraray having a viscosity of 105 Pas) are dissolved in 100 ml of toluene at room temperature (25° C.). Then 4.2 g (0.04 mol) of triethylamine are added. The solution is homogeneous after a brief time and is colorless and clear. 5.3 g (0.034 mol) of phenyl chloroformate, pre-dissolved in 8 ml of toluene, are uniformly added dropwise to the reaction solution over a period of 45-75 minutes. The reaction mixture is further stirred for at least 8 hours. The reaction mixture is then cooled down to ca. 8° C. The resulting precipitate of triethylamine hydrochloride is filtered off and washed off with a little toluene. The solvent is then removed under reduced pressure. The product obtained in high yield is phenyl carbonate-terminated polyester having a viscosity of 101 Pas.

##STR00016##

[0070] 50 g (0.008 mol) of the phenyl carbonate-terminated polymer are left to react with 3.0 g (0.016 mol) of 3-aminopropyltrimethoxysilane (Evonik) at 25° C. for at least 12 h. The phenol formed remains behind in dissolved form in the colorless to slightly yellowish, clear reaction mixture. The product obtained is trimethoxysilane-terminated polyester having a viscosity of 107 Pas. The trimethoxysilane groups are attached to the polyester via a urethane bond.

##STR00017##

[0071] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.

COMPARATIVE EXAMPLE

[0072] 100 g (0.016 mol) of polyester diol (polyol P-6010 from Kuraray having a viscosity of 105 Pas) are stirred with 5.35 g (0.033 mol) of carbonyldiimidazole (CDI) at 60° C. for 12 h under nitrogen. The product obtained is imidazole carbamate-terminated polyether having a viscosity of 124 Pas.

[0073] 50 g (0.008 mol) of the imidazole carbamate-terminated polymer are reacted with 3.0 g (0.016 mol) of 3-aminopropyltrimethoxysilane (Evonik) at 60° C. for 24 h. Trimethoxysilane-terminated polyether having a viscosity of 190 Pas is obtained as product. The trimethoxysilane groups are attached to the polyether via a urethane bond.

Formulation Examples 7-8

[0074] The following formulations (data in percent by weight) were mixed in a speed mixer (DAC 1100 FVZ, Hauschild) and filled into 310 ml PE cartridges (Ritter). The finished formulations were stored in a standard climate (23° C./50% RH), and the viscosity after storage was measured with a rheometer (RS6000, Haake). Whereas formulation example 7 shows the increase in viscosity typical of silane-terminated polymers on storage, in formulation example 8 the viscosity decreases on storage. This indicates degradation of the polymer chains.

TABLE-US-00001 Formulation Formulation example 7 example 8 Trimethoxysilane-terminated 34.9%   polyester from Ex 6 Trimethoxysilane-terminated 34.9%   polyester from comparative example Vinyltrimethoxysilane 1% 1% Omyalite 95T 50%  50%  Titanium dioxide 2% 2% Thixatrol MAX 2% 2% Diisononyl phthalate 9% 9% 3-Aminopropyltrimethoxysilane 1% 1% 1,8-Diaza-bicyclo[5.4.0]undec-7-ene 0.1%.sup.  0.1%.sup.  Viscosity at 10 s.sup.−1 [Pas] 331 303 after storage of the cartridge in a standard climate for 1 day Viscosity at 10 s.sup.−1 [Pas] 399 224 after storing the cartridge in a standard climate for 7 days

Example 9 Carbamate-Terminated Polyether with Aminosilane

[0075] 80 g (0.02 mol) of polyether diamine having an average molar mass of 4000 g/mol (available from Sigma-Aldrich) are dissolved in 100 ml of toluene at room temperature (25° C.). Then 5.1 g (0.05 mol) of triethylamine are added. The solution, which is homogeneous after a short time, is yellow and clear. 2.5 g (0.016 mol) of phenyl chloroformate, pre-dissolved in 8 ml of toluene, are uniformly added dropwise to the reaction solution over a period of 45-75 minutes. The reaction mixture is further stirred for at least 8 hours. The reaction mixture is then cooled down to ca. 8° C. The resulting precipitate of triethylamine hydrochloride is filtered off and washed off with a little toluene. The solvent is then removed under reduced pressure. The product obtained is phenyl carbamate-terminated polyether in high yield.

##STR00018##

[0076] 42 g (0.01 mol) of the phenyl carbonate-terminated polymer are reacted with 3.6 g (0.02 mol) of 3-aminopropyltrimethoxysilane (Evonik) at a bath temperature of 50° C. 0.03 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (Sigma-Aldrich) are added to the reaction mixture as catalyst. The reaction is complete after 17 hours at the latest. The phenol formed remains in dissolved form in the yellow, clear reaction mixture. Trimethoxysilane-terminated polyether is obtained as product. The trimethoxysilane groups are attached to the polyether via a urea bond.

##STR00019##

[0077] The polymer can be used for producing moisture-curing adhesives, sealants and coating materials based on silane-terminated polymers.