Process for preparing polyalkylene ether-modified polysiloxanes and use thereof

Abstract

The invention relates to a process for preparing oligo- or polyalkylene ether-modified polysiloxanes by transesterification of alkoxy-functionalized polysiloxanes with OH terminated oligo- or polyalkylene ethers in the presence of the tetra-n-C.sub.1-C.sub.6-alkoxy-titanate as catalyst. Oligo- or polyalkylene ether-modified polydimethylsiloxanes obtainable through this process are suitable as defoamers, as wetting agents, and as additives in coating material formulations.

Claims

1. A process for preparing at least one polysiloxane having at least one oligo- or polyalkylene ether group, the process comprising: reacting a polysiloxane having at least one C.sub.1-C.sub.6 alkoxy group bonded to a silicon atom of the polysiloxane with an OH-terminated oligo- or polyalkylene ether of formula (3a) in the presence of a tetra-C.sub.1-C.sub.6 alkoxytitanate;
R-[O-A].sub.k-OH(3a), wherein A is C.sub.2-C.sub.4 alkane-1,2-diyl, k is a number from 2 to 100, and R is a monovalent hydrocarbon radical having 1 to 20 C atoms.

2. The process of claim 1, wherein the OH-terminated oligo- or polyalkylene ether and the polysiloxane are reacted in a proportion such that a molar ratio of OH groups in the oligo- or polyalkylene ether to the at least one C.sub.1-C.sub.6 alkoxy group in the polysiloxane is from 0.8:1 to 2:1.

3. The process of claim 1, wherein the reacting is carried out in an aprotic organic solvent.

4. The process of claim 1, the tetra-C.sub.1-C.sub.6 alkoxytitanate are used in an amount of 0.05 to 1 wt %, based on a total weight of a reaction mixture.

5. The process of claim 1, wherein the tetra-C.sub.1-C.sub.6 alkoxytitanate is selected from the group consisting of tetramethoxytitanate, tetraethoxytitanate, tetra-n-propoxytitanate, tetraisopropoxytitanate and tetra-n-butoxytitanate.

6. The process of claim 1, wherein a C.sub.1-C.sub.6 alkanol which forms during the reacting is at least partly removed during the reacting by distillation from a reaction mixture.

7. The process of claim 1, wherein the polysiloxane has at least one element selected from the group of elements consisting of: the polysiloxane comprises on average 5 to 30 silicon atoms, the polysiloxane comprises 1 to 6 C.sub.1-C.sub.6 alkoxy groups bonded to in each case one silicon atom of the polysiloxane, the polysiloxane is a linear polysiloxane which carries a C.sub.1-C.sub.6 alkoxy group on each of two terminal silicon atoms, the polysiloxane is a polydimethylsiloxane, and the at least one C.sub.1-C.sub.6 alkoxy group bonded to the silicon atom of the polysiloxane is selected from methoxy and ethoxy.

8. The process of claim 1, wherein the polysiloxane reacted with the OH-terminated oligo- or polyalkylene ether of formula (3a) is obtained by reacting a linear or cyclic polysiloxane having 2 to 6 silicon atoms with a C.sub.1-C.sub.6 alkoxysilane of formula:
(R.sup.9O).sub.mR.sup.10.sub.4-mSi wherein R.sup.9 is C.sub.1-C.sub.6 alkyl, R.sup.10 is C.sub.1-C.sub.6 alkyl, C.sub.3-C.sub.6 cycloalkyl, phenyl, C.sub.2-C.sub.6 alkenyl, or C.sub.2-C.sub.6 alkynyl, and m is 1, 2, 3, or 4.

9. The process as claimed in claim 8, wherein m is 2.

10. The process as claimed in claim 8, wherein R.sup.9 is methyl or ethyl and R.sup.10 is methyl.

Description

EXAMPLES

(1) Analysis

(2) Determination of Dynamic Coefficient of Friction

(3) The dynamic coefficient of friction (COF) is determined using a COF tester from RAY-RAN Test Equipment Ltd by the Pull-Meter method (ASTM C-1028-96).

(4) Determination of Gloss and Haze

(5) Gloss and haze were determined using a micro-Tri-gloss from BYK-Gardner.

(6) Gel Permeation Chromatography (GPC)

(7) The gel permeation chromatography was carried out using a 1260 Infinity from Agilent. Two ResiPore columns (3007.5 mm; 3 m) were used. The eluent employed was tetrahydrofuran (1 mL/minute) at an oven temperature of 40 C. Detection took place using an RI detector.

(8) .sup.1H-NMR Spectroscopy

(9) The .sup.1H-NMR spectra were recorded in CDCl.sub.3 using a 400 MHz NMR spectrometer from Bruker.

(10) Materials Used

(11) Octamethylcyclotetrasiloxane (97%, ABCR)

(12) Dimethyldiethoxysilane (97%, ABCR)

(13) Trifluoromethanesulfonic acid (98%, Sigma-Aldrich)

(14) Tri-n-butylamine (>98.5%, Sigma-Aldrich)

(15) Xylene (96%, Sigma-Aldrich)

(16) Clear PE Panels Form P 300-7C (PET sheet, LAU GmbH)

(17) Preparation of the Alkoxy-Functionalized Siloxanes

(18) Preparation of siloxane 1: CH.sub.3CH.sub.2OSi(CH.sub.3).sub.2O(Si(CH.sub.3).sub.2O).sub.12Si(CH.sub.3).sub.2OCH.sub.2CH.sub.3

(19) 3120 g Octamethylcyclotetrasiloxane, 694 g dimethyldiethoxysilane, and 2.5 g of trifluoromethanesulfonic acid were combined in a 5 L reactor and stirred at 60 C. for 6 hours. After the establishment of equilibrium, determined via the increase in the solids fraction of the mixture, the catalyst was neutralized by addition of 4 g of tri-n-butylamine. The reaction mixture was filtered and unreacted starting materials and low molecular mass oligomers formed as byproducts were removed by stripping under reduced pressure. The product obtained was analyzed by NMR spectroscopy. It comprised 3242 g of the siloxane 1.

(20) Preparation of siloxane 2: CH.sub.3CH.sub.2OSi(CH.sub.3).sub.2O(Si(CH.sub.3).sub.2O).sub.22Si(CH.sub.3).sub.2OCH.sub.2CH.sub.3

(21) 2700 g Octamethylcyclotetrasiloxane, 300 g dimethyldiethoxysilane, and 2.5 g of trifluoromethanesulfonic acid were combined in a 5 L reactor and stirred at 60 C. for 6 hours. After the establishment of equilibrium, determined via the increase in the solids fraction of the mixture, the catalyst was neutralized by addition of 4 g of tri-n-butylamine. The reaction mixture was filtered and unreacted starting materials and low molecular mass oligomers formed as byproducts were removed by stripping under reduced pressure. The product obtained was analyzed by NMR spectroscopy. It comprised 2550 g of the siloxane 2.

(22) Transalkoxylation of the Alkoxy-Functionalized Siloxanes

(23) The quantities of siloxane, polyalkylene ether, xylene, and tetra-n-butoxytianate indicated in table 1 were mixed and the mixture was heated slowly to 160 with stirring. The reaction mixture was stirred for 8 hours at this temperature and at the same time ethanol and parts of the solvent were removed by distillation. The progress of the reaction was monitored by gel permeation chromatography. Following complete conversion, the solvent was removed under reduced pressure until the solids content was >98 wt %. The products obtained were used further without additional purification.

(24) Polyalkylene ethers employed for the transalkoxylation were as follows (with weight-average molecular weights in parentheses):

(25) Polyether 1: n-butyldiethylene glycol (162 g/mol)

(26) Polyether 2: methyltripropylene glycol (222 g/mol)

(27) Polyether 3: n-butylpolypropylene glycol (1350 g/mol)

(28) Polyether 4: Methylpolyethylene glycol (350 g/mol)

(29) Polyether 5: Methylpolyethylene glycol (500 g/mol)

(30) Polyether 6: allyl polyether with ethylene glycol and propylene glycol units (554 g/mol)

(31) Polyether 7: allyl polyether with ethylene glycol and propylene glycol units (950 g/mol)

(32) Polyether 8: n-butylpolypropylene glycol (1200 g/mol)

(33) Polyether 9: allylpolyethylene glycol (500 g/mol)

(34) Polyether 10: allylpolypropylene glycol (975 g/mol)

(35) TABLE-US-00001 TABLE 1 Polyalkylene Example Siloxane ether Solvent Catalyst 1 30 g Siloxane 1 15 g Polyether 1 0.3 g Tetra-n-butoxytitanate 2 30 g Siloxane 1 19 g Polyether 2 20 g Xylene 0.3 g Tetra-n-butoxytitanate 3 10 g Siloxane 1 28 g Polyether 3 35 g Xylene 0.2 g Tetra-n-butoxytitanate 4 20 g Siloxane 1 13 g Polyether 4 30 g Xylene 0.2 g Tetra-n-butoxytitanate 5 20 g Siloxane 1 18 g Polyether 5 40 g Xylene 0.2 g Tetra-n-butoxytitanate 6 30 g Siloxane 1 29 g Polyether 6 40 g Xylene 0.2 g Tetra-n-butoxytitanate 7 20 g Siloxane 1 38 g Polyether 7 40 g Xylene 0.2 g Tetra-n-butoxytitanate 8 16 g Siloxane 2 20 g Polyether 8 50 g Xylene 0.2 g Tetra-n-butoxytitanate 9 25 g Siloxane 2 21 g Polyether 9 44 g Xylene 0.2 g Tetra-n-butoxytitanate 10 20 g Siloxane 2 17 g Polyether 10 50 g Xylene 0.2 g Tetra-n-butoxytitanate

(36) Use Examples

(37) Use as Flow Control Assistant

(38) The test formulation used was a diluted Joncryl 8052 dispersion (BASF SE) (9.24 g of water, 90.76 g of Joncryl 8052). The amounts of the example compounds indicated in table 2 were incorporated into 25 g portions of the diluted Joncryl 8052 dispersion using an electrical mixer at 2500 revolutions/minute over 2 minutes. The weight % indicated in table 2 are based on the total weight of the dispersion. The formulations were applied using a 60 m doctor blade at a rate of 10 mm/s onto the PET sheet. The samples were dried for 24 hours and measurements were made of the dynamic coefficient of friction and of the gloss and haze. Surface structure and craters were rated visually on a scale from 1 to 8 (1=very good, 8=very poor). The reference used was the commercially available, polyether-modified polysiloxane Efka SL-3299 (BASF SE).

(39) TABLE-US-00002 TABLE 2 Dynamic coefficient Surface Example Polyethersiloxane of friction structure Craters Haze Gloss 11 (C) 1.222 2 5 167 224 12 (C) Efka SL-3299, 1.173 1 1 103 232 0.2 wt % 13 (C) Efka SL-3299, 0.9347 2 1 97.3 232 0.5 wt % 14 (C) Efka SL-3299, 0.9166 3 8 100 232 1 wt % 15 Example 9, 0.2 wt % 0.5901 2 3 100 232 16 Example 9, 0.5 wt % 0.572 2 3 117 233 17 Example 9, 1 wt % 0.5499 1 3 103 233 18 Example 4, 0.2 wt % 0.6766 2 3 101 234 19 Example 4, 0.5 wt % 0.579 1 5 97.3 234 20 Example 4, 1 wt % 0.4562 2 6 97 233 21 Example 5, 0.2 wt % 0.6473 3 3 160 224 22 Example 5, 0.5 wt % 0.4492 2.5 2 168 223 23 Example 5, 1 wt % 0.3544 2 1 129 225 24 Example 6, 0.2 wt % 0.8957 2 2 100 235 25 Example 6, 0.5 wt % 0.8524 2 1 97 235 26 Example 6, 1 wt % 0.5078 2 2 91 236 (C): noninventive comparative example

(40) Use as Defoamers

(41) The test formulation used was a diluted Acronal LR9014 dispersion (BASF SE) (35 g of water, 85 g of Acronal LR9014). The example compounds indicated in table 3 were incorporated into the dispersion by stirring with an electric mixer at 4500 revolutions/minute over 3 minutes. In all of the use examples, the concentration of the example compounds in the dispersions was 0.42 wt %, based on the total weight of the dispersion. Immediately after the example compound had been incorporated, a pycnometer (stainless steel, 100 cm.sup.3) was used to determine the density of the formulation. The reference density of the fully deaerated, diluted Acronal LR9014 dispersion was 1.101 g/cm.sup.3.

(42) For compatibility testing, the dispersions were applied with a film thickness of 100 m, using a doctor blade, at a rate of 10 mm/s onto the PET sheet. The fully cured films were inspected.

(43) For assessment of the storage stability, after 14-day storage at 45 C., the dispersions were stirred with an electric mixer at 4500 revolutions/minute for 3 minutes and their density was measured using the pycnometer.

(44) The films were inspected on a scale from 1 to 4 (1=film satisfactory, no significant cratering or specks, 2=film satisfactory, slight unevenness, sporadic cratering or specks, 3=surface very uneven, massive cratering and specks, 4=no film formed, owing to incompatibility).

(45) TABLE-US-00003 TABLE 3 Density in g/cm.sup.3, Density in Polyether- measured Compatibility g/cm.sup.3, after Compatibility Example siloxane immediately after 1 day 14 days after 14 days 27 (C) 0.648 n.d. 0.662 n.d. 28 (C) Efka SI 2210 0.994 1.5 0.875 2.5 29 (C) Efka SI 2550 1.101 3 1.057 3 30 Example 2 1.099 1 1.042 1 31 Example 8 0.991 1 1.047 1 32 Example 10 1.021 1.5 1.036 1.5 (C): noninventive comparative example n.d.: not determined