METHOD FOR PREPARING MIXED SILANE-TERMINATED POLYMERS

Abstract

The invention relates to a method for preparing a silane-terminated polymer by reacting a polyol A) with a diisocyanate B), an isocyanatosilane C) and an amino silane E), wherein the polyol component A) is reacted simultaneously with a mixture of at least one diisocyanate B) and one isocyanatosilane C), and the resulting product is subsequently reacted with the amino silane E) to produce the silane-terminated polymer. The method according to the invention can be used to prepare mixed silane-terminated polymers having a low viscosity.

Claims

1.-17. (canceled)

18. A process for preparing a mixed silane-terminated polymer by a) simultaneously reacting the hydroxyl groups of a polyol component A) with at least one diisocyanate B) and at least one isocyanatosilane C) in the presence of at least one catalyst D), and b) subsequently reacting the free NCO groups of the reaction product from step a) with an aminosilane E).

19. The process as claimed in claim 18, wherein the polyol component A) is a polyether polyol having a number-average molecular weight in a range from 3000 to 24 000 g/mol.

20. The process as claimed in claim 18, wherein the polyol component A) is a polyether polyol having a number-average molecular weight of 5000 to 16 000 g/mol.

21. The process as claimed in claim 18, wherein the polyol component A) is a polyether polyol based on polypropylene oxide.

22. The process as claimed in claim 18, wherein the diisocyanate B) used is an aliphatic, cycloaliphatic or araliphatic diisocyanate or mixtures thereof.

23. The process as claimed in claim 18, wherein the diisocyanate B) is selected from the group consisting of 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, hexahydrotolylene 2,4-diisocyanate, hexahydrotolylene 2,6-diisocyanate, tolylene 2,4- diisocyanate, tolylene 2,6-diisocyanate, and mixtures thereof.

24. The process as claimed in claim 18, wherein the diisocyanate B) used is 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate).

25. The process as claimed in claim 18, wherein the isocyanatosilane C) is a compound of formula (II) ##STR00016## in which R.sup.1, R.sup.2 and R.sup.3 independently of one another are identical or different saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or optionally substituted aromatic or araliphatic radicals which have up to 18 carbon atoms and may optionally contain up to 3 heteroatoms from the group of oxygen, sulfur, nitrogen, with the proviso that at least one of the radicals R.sup.1, R.sup.2 and R.sup.3 is joined to the silicon atom via an oxygen atom, and X is a linear or branched organic radical having up to 6 carbon atoms.

26. The process as claimed in claim 18, wherein the isocyanatosilane C) used is 3-isocyanatopropyltrimethoxysilane.

27. The process as claimed in claim 18, wherein the aminosilane E) is a compound of formula (VIII) ##STR00017## in which R.sup.1, R.sup.2, R.sup.3 and X have the definition given in claim 25 and R.sup.10 is hydrogen, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms or a radical of the formula ##STR00018## in which R.sup.1, R.sup.2, R.sup.3 and X have the definition given above.

28. The process as claimed in claim 18, wherein the aminosilane E) is a compound of formula (IX) ##STR00019## in which R.sup.1, R.sup.2 and R.sup.3 have the definition given in claim 25 X is a linear or branched organic radical having at least 2 carbon atoms and R.sup.11 and R.sup.12 independently of one another are saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or aromatic organic radicals which have 1 to 18 carbon atoms, are substituted or unsubstituted and/or have heteroatoms in the chain.

29. The process as claimed in claim 18, wherein the amount of aminosilane E) is chosen such that there are 0.8 to 1.2 amino groups for each isocyanate group of the isocyanate- and silane-functional polymer formed in process step a).

30. The process as claimed in claim 18, wherein the reaction with the diisocyanate B) and the isocyanatosilane C) is conducted in the presence of an Sn-, Ti- or Yb-containing catalyst D).

31. The process as claimed in claim 18, wherein the catalyst D) is selected from Sn(II)-, Sn(IV)- and Yb(III)-containing compounds and an organotitanate of formula (VI) ##STR00020## where R.sup.4 is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms; R.sup.5 is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms and optionally having heteroatoms; R.sup.6 is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or a linear or branched alkoxy group having 1 to 8 carbon atoms; R.sup.7 is a linear or branched alkyl radical having 2 to 20 carbon atoms; and n is a value of 1 or 2.

32. The process as claimed in claim 18, wherein the catalyst is selected from an organotitanate and a -diketonate compound of the transition metals scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium.

33. The process as claimed in claim 18, wherein the molar amount of the isocyanatosilane C) used is in the range from 1 to 50 mol % and the molar amount of the diisocyanate B) used is accordingly in the range from 50 to 99 mol %, based on the number of hydroxyl groups of polyol A).

34. A method comprising utilizing the silane-terminated polymers prepared by the process of claim 18 as binders in coating compositions, sealants or as adhesives.

Description

EXAMPLES

[0113] All reported percentages are based on weight unless otherwise stated.

[0114] The NCO contents were determined by titrimetry according to DIN EN ISO 11909.

[0115] OH numbers were determined by titrimetry according to DIN 53240 T.2.

[0116] All viscosity measurements were made with a Physica MCR 51 rheometer from Anton Paar Germany GmbH (Germany) to DIN EN ISO 3219.

[0117] The Hazen color number was measured by spectrophotometry according to DIN EN ISO 6271-2:2004 with a LICO 400 spectrophotometer from Lange, Germany.

[0118] The reported molecular weights are in each case number-average molecular weights (Mn) which can be determined by gel permeation chromatography.

[0119] For the practical performance of the following examples, it should be noted that the contents in the substances used of the groups that are relevant to the respective reaction (e.g. amine content of the aminosilane) have been determined by specific determination methods (e.g. titration) and the amounts actually used have been calculated on the basis of contents of in each case 100%.

Example 1 (Comparative Example)

[0120] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1367.7 g (0.16 mol) of a propylene glycol with an OH number of 13.4 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were stirred with 35.3 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 160 ppm of Valikat Bi 2810 (bismuth(III) neodecanoate) (Umicore Specialty Materials, Bruges, Belgium) until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 36.3 g (0.16 mol) of isophorone diisocyanate was rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.47% had been reached. After addition of 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was thus obtained had a viscosity of 18 600 mPas and a color number of 28 APHA.

Example 2 (According to the Invention)

[0121] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1367.7 g (0.16 mol) of a propylene glycol with an OH number of 13.4 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 36.3 g (0.16 mol) of isophorone diisocyanate and 35.3 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 160 ppm of Valikat Bi 2810 (bismuth(III) neodecanoate) (Umicore Specialty Materials, Bruges, Belgium) until the theoretical NCO content of 0.47% had been reached. Subsequently, 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 30 900 mPas and a color number of 26 APHA.

Example 3 (Comparative Example)

[0122] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.3 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were stirred with 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 35.8 g (0.16 mol) of isophorone diisocyanate were rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.47% had been reached. After addition of 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 13 600 mPas and a color number of 18 APHA.

Example 4 (Comparative Example)

[0123] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.3 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 35.8 g (0.16 mol) of isophorone diisocyanate at 60 C. with addition of 40 ppm of dibutyltin dilaurate until the theoretical NCO content of 0.47% had been reached. After addition of 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. Thereafter, 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) were rapidly added dropwise and the mixture was stirred again until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 13 000 mPas and a color number of 20 APHA.

Example 5 (According to the Invention)

[0124] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.3 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 35.8 g (0.16 mol) of isophorone diisocyanate and 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until the theoretical NCO content of 0.47% had been reached. Subsequently, 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocya- nate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 12 900 mPas and a color number of 16 APHA.

[0125] These examples show that silane-terminated polymers having a low viscosity can be obtained by means of the simplified process according to the invention as per example 5. Surprisingly, the polymers prepared in accordance with the invention do not differ substantially in terms of their viscosity from those that have been prepared by means of the processes known from the prior art (examples 3 and 4). It was thus shown that it is possible by way of the process according to the invention to prepare silane-terminated polymers in only two reaction steps, without the viscosity of the polymers being impaired, that is to say rising.

Example 6 (Comparative Example)

[0126] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were stirred with 18.9 g (0.089 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 51.3 g (0.231 mol) of isophorone diisocyanate were rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.68% had been reached. After addition of 81.2 g (0.231 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 21 200 mPas and a color number of 22 APHA.

Example 7 (According to the Invention)

[0127] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 51.3 g (0.231 mol) of isophorone diisocyanate and 18.9 g (0.089 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker

[0128] Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until the theoretical NCO content of 0.68% had been reached. Subsequently, 81.2 g (0.231 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 20 200 mPas and a color number of 18 APHA.

Example 8 (Comparative Example)

[0129] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were stirred with 18.0 g (0.08 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 53.3 g (0.24 mol) of isophorone diisocyanate were rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.68% had been reached. After addition of 84.3 g (0.24 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 23 500 mPas and a color number of 28 APHA.

Example 9 (According to the Invention)

[0130] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 53.3 g (0.24 mol) of isophorone diisocyanate and 18.0 g (0.08 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until the theoretical NCO content of 0.68% had been reached. Subsequently, 84.3 g (0.24 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that is obtained has a viscosity of 20 900 mPas and a color number of 24 APHA.

Example 10 (Comparative Example)

[0131] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N from Covestro Deutschland AG; Leverkusen, Germany) were stirred with 6.7 g (0.03 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40 from Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 63.0 g (0.28 mol) of isophorone diisocyanate were rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.85% had been reached. After addition of 98.4 g (0.28 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 34 900 mPas and a color number of 18 APHA.

Example 11 (According to the Invention)

[0132] In a 2 sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1349.7 g (0.16 mol) of a propylene glycol with an OH number of 13.3 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 63.0 g (0.28 mol) of isophorone diisocyanate and 6.7 g (0.03 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 40 ppm of dibutyltin dilaurate until the theoretical NCO content of 0.85% had been reached. Subsequently, 98.4 g (0.28 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 29 200 mPas and a color number of 14 APHA.

Example 12 (Comparative Example)

[0133] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.6 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were stirred with 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 120 ppm of the Tyzor IBAY titanium catalyst (abcr GmbH, Karlsruhe, Germany) until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 35.9 g (0.16 mol) of isophorone diisocyanate were rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.47% had been reached. After addition of 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that is obtained has a viscosity of 15 050 mPas and a color number of 36 APHA.

Example 13 (According to the Invention)

[0134] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.6 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 35.9 g (0.16 mol) of isophorone diisocyanate and 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 120 ppm of the Tyzor IBAY titanium catalyst (abcr GmbH, Karlsruhe, Germany) until the theoretical NCO content of 0.47% had been reached. Subsequently, 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 13 700 mPas and a color number of 30 APHA.

Example 14 (Comparative Example)

[0135] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.6 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were stirred with 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 120 ppm of Yb(acac).sub.3 (abcr GmbH, Karlsruhe, Germany) until it was no longer possible to observe any isocyanate band in the IR spectrum. Subsequently, 35.9 g (0.16 mol) of isophorone diisocyanate was rapidly added dropwise and prepolymerization was effected until the theoretical NCO content of 0.47% had been reached. After addition of 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5), the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 16 500 mPas and a color number of 16 APHA.

Example 15 (According to the Invention)

[0136] In a 2 l sulfonation flask with lid, stirrer, thermometer and nitrogen flow, 1369.6 g (0.16 mol) of a propylene glycol with an OH number of 13.2 (Acclaim Polyol 8200 N, Covestro Deutschland AG; Leverkusen, Germany) were prepolymerized with 35.9 g (0.16 mol) of isophorone diisocyanate and 34.2 g (0.16 mol) of 3-isocyanatopropyltrimethoxysilane (Geniosil GF 40, Wacker Chemie AG; Munich, Germany) at 60 C. with addition of 120 ppm of Yb(acac).sub.3 (abcr GmbH, Karlsruhe, Germany) until the theoretical NCO content of 0.47% had been reached. Subsequently, 56.2 g (0.16 mol) of diethyl N-(3-trimethoxysilylpropyl)aspartate (prepared according to EP-A 596 360, example 5) were rapidly added dropwise and the mixture was stirred until it was no longer possible to observe any isocyanate band in the IR spectrum. The polyurethane prepolymer having alkoxysilyl end groups that was obtained had a viscosity of 16 000 mPas and a color number of 14 APHA.