ALKOXYSILANE-FUNCTIONALIZED AND ALLOPHANATE-FUNCTIONALIZED URETHANES

Abstract

The present invention relates to alkoxysilane-functionalized and allophanate-functionalized urethanes, methods for the preparation thereof, coating compositions comprising these and to the use thereof.

Claims

1. An alkoxysilane-functionalized and allophanate-functionalized urethane comprising the reaction product of I. A) at least one alkoxysilane group-containing monourethane A) of the formula 1
R.sub.n(OR.sup.1).sub.3-nSi—R.sup.2—NH—(C═O)—OR.sup.3   formula 1 where R.sub.n, R.sup.1, R.sup.2 and R.sup.3 are each independently hydrocarbyl radicals having 1-8 carbon atoms, which may be linear, branched or cyclic, or else may be integrated together to form a cyclic system, and n is 0-2, and B) at least one diisocyanate B), in a molar ratio of A) to B) of from 1.0:1.5 to 1.0:0.6, optionally in the presence of at least one catalyst K), II. and the subsequent reaction C) with at least one diol and/or polyol C), optionally in the presence of at least one catalyst K), in the ratio of the NCO groups of reaction product I. to the OH groups of the diol and/or polyol II. C) of from 1.0:1.5 to 1.0:0.6.

2. An alkoxysilane-functionalized and allophanate-functionalized urethane, obtained by reacting I. A) at least one alkoxysilane group-containing monourethane A) of the formula 1
R.sub.n(OR.sup.1).sub.3-nSi—R.sup.2—NH—(C═O)—OR.sup.3   formula 1 where R.sub.n, R.sup.1, R.sup.2 and R.sup.3 are each independently hydrocarbyl radicals having 1-8 carbon atoms, which may be linear, branched or cyclic, or else may be integrated together to form a cyclic system, and n is 0-2, and B) at least one diisocyanate B), in a molar ratio of A) to B) of from 1.0:1.5 to 1.0:0.6, optionally in the presence of at least one catalyst K), II. and subsequent reaction C) with at least one diol and/or polyol C), optionally in the presence of at least one catalyst K), in the ratio of the NCO groups of reaction product I. to the OH groups of the diol and/or polyol II. C) of 1.0:1.5 to 1.0:0.6.

3. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein R.sub.n, R.sup.1, R.sup.2 and R.sup.3 are at the same time or each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl.

4. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein n is 0, R.sup.1 and R.sup.3 are at the same time or each independently methyl or ethyl, and R.sup.2 is at the same time or each independently methyl or propyl.

5. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein n is 0 and R.sup.2 is methyl or propyl, and R.sup.1 is methyl or ethyl and R.sup.3═R.sup.1.

6. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein n is 0, R.sup.1 and R.sup.3 are methyl and R.sup.2 is propyl.

7. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diisocyanate B) is selected from isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 2,2′-dicyclohexylmethane diisocyanate (2,2′-H12MDI), 2,4′-dicyclohexylmethane diisocyanate (2,4′-H12MDI), 4,4′-dicyclohexylmethane diisocyanate (4,4′-H12MDI), 2-methylpentane diisocyanate (MPDI), pentane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (2,2,4-TMDI), 2,4,4-trimethylhexamethylene diisocyanate (2,4,4-TMDI), norbornane diisocyanate (NBDI), methylenediphenyl diisocyanate (MDI), toluidine diisocyanate (TDI), tetramethylxylylene diisocyanate (TMXDI), xylylene diisocyanate (MXDI), individually or in mixtures.

8. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diol and/or polyol C) is selected from ethylene glycol, propane-1,2-diol, propane-1,3-diol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, butane-1,2-diol, butane-1,4-diol, butylethylpropane-1,3-diol, methylpropane-1,3-diol, pentane-1,5-diol, bis(1,4-hydroxymethyl)cyclohexane (cyclohexanedimethanol), glycerol, hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, bisphenol A, bisphenol B, bisphenol C, bisphenol F, norbornylene glycol, 1,4-benzyldimethanol, 1,4-benzyldiethanol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 1,4-butylene glycol, 2,3-butylene glycol, di-β-hydroxyethylbutanediol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, decanediol, dodecanediol, neopentyl glycol, cyclohexanediol, 3(4),8(9)-bis(hydroxymethyl)tricyclo[5.2.1.0.sup.2,6]decane (dicidol), 2,2-bis(4-hydroxycyclohexyl)propane, 2,2-bis[4-(β-hydroxyethoxy)phenyl]propane, 2-methylpropane-1,3-diol, 2-methylpentane-1,5-diol, 2,2,4(2,4,4)-trimethylhexane-1,6-diol, hexane-1,2,6-triol, butane-1,2,4-triol, tris(β-hydroxyethyl) isocyanurate, mannitol, sorbitol, polypropylene glycols, polybutylene glycols, xylylene glycol or neopentyl glycol hydroxypivalate, alone or in mixtures.

9. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diol and/or polyol C) is selected from ethylene glycol, triethylene glycol, butane-1,4-diol, propane-1,2-diol, pentane-1,5-diol, hexane-1,6-diol, cyclohexanedimethanol, decanediol, dodecane-1,12-diol, 2,2,4-trimethylhexane-1,6-diol, 2,4,4-trimethylhexane-1,6-diol, 2,2-dimethylbutane-1,3-diol, 2-methylpentane-2,4-diol, 3-methylpentane-2,4-diol, 2,2,4-trimethylpentane-1,3-diol, 2-ethylhexane-1,3-diol, 2,2-dimethylhexane-1,3-diol, 3-methylpentane-1,5-diol, 2-methylpentane-1,5-diol, trimethylolpropane, 2,2-dimethylpropane-1,3-diol (neopentyl glycol), neopentyl glycol hydroxypivalate and cis/trans-cyclohexane-1,4-diol, alone or in mixtures.

10. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diol and/or polyol C) is selected from pentane-1,5-diol, hexane-1,6-diol, dodecane-1,12-diol, 2,2,4-trimethylhexane-1,6-diol, 2,4,4-trimethylhexane-1,6-diol, 2,2-dimethylbutane-1,3-diol, 2-methylpentane-2,4-diol, 3-methylpentane-2,4-diol, 2,2,4-trimethylpentane-1,3-diol, 2-ethylhexane-1,3-diol, 2,2-dimethylhexane-1,3-diol, 3-methylpentane-1,5-diol, 2-methylpentane-1,5-diol, 2,2-dimethylpropane-1,3-diol (neopentyl glycol) and cis/trans-cyclohexane-1,4-diol, alone or in mixtures.

11. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diol and/or polyol C) is selected from hydroxyl group-containing polyesters, polyethers, polyacrylates, polycarbonates and polyurethanes having an OH number of 20 to 500 mg KOH/g and a mean molar mass of 250 to 6000 g/mol, alone or in mixtures.

12. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the diol and/or polyol C) is selected from hydroxyl group-containing polyesters or polyacrylates having an OH number of 50 to 250 mg KOH/g and a mean molecular weight of 500 to 6000 g/mol, alone or in mixtures.

13. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the catalyst K) is selected from the group consisting of metal carboxylates, tert-amines, amidine, guanidine, quaternary ammonium salts, tetraalkylammonium salts, quaternary phosphonium salts, metal acetylacetonates, quaternary ammonium acetylacetonates, quaternary phosphonium acetylacetonates, carboxylic acids, aluminium alkoxides, zirconium alkoxides, titanium alkoxides and/or boron alkoxides and/or esters thereof, phosphorus- and nitrogen-containing catalysts, sulphonic acids, alone or in mixtures.

14. The alkoxysilane-functionalized and allophanate-functionalized urethane according to claim 1, wherein the catalyst K) is zinc acetylacetonate and/or zinc ethylhexanoate.

15. The method for preparing alkoxysilane-functionalized and allophanate-functionalized urethanes according to claim 1, by reacting I. A) at least one alkoxysilane group-containing monourethane A) of the formula 1
R.sub.n(OR.sup.1).sub.3-nSi—R.sup.2—NH—(C═O)—OR.sup.3   formula 1 wherein R.sub.n, R.sup.1, R.sup.2 and R.sup.3 independently of one another represent hydrocarbon radicals having 1-8 carbon atoms, wherein these may be linear, branched or cyclic or else may be integrated together to form a cyclic system, and n represents 0-2, and B) at least one diisocyanate B), in a molar ratio of A) to B) of from 1.0:1.5 to 1.0:0.6 optionally in the presence of at least one catalyst K), II. and the subsequent reaction C) with at least one diol and/or polyol C), optionally in the presence of at least one catalyst K), in the ratio of the NCO groups of reaction product I. to the OH groups of the diol and/or polyol II. C) of 1.0:1.5 to 1.0:0.6.

16. The method according to claim 15, wherein the reaction of step I. or II. is carried out at temperatures in the range from 15 to 40° C.

17. The method according to claim 15, wherein the reaction of step I. or II. is carried out at temperatures in the range from 80 to 220° C.

18. The method according to claim 15, wherein the reaction of step I. is carried out in the presence of zinc acetylacetonate and/or zinc ethylhexanoate as catalyst K).

19. The method according to claim 15, wherein the reaction of the residual amount of NCO groups of B) with an alcohol D) is carried out at temperatures in the range of 30-150° C.

20. The method according to claim 15, wherein the remaining NCO groups of reaction product I. are reacted with the OH groups of the diol and/or polyol II. C) in the ratio of NCO groups to OH groups of from 0.8:1 to 1.2:1.

21. A coating composition, adhesive or sealant comprising: at least one alkoxysilane-functionalized and allophanate-functionalized urethane comprising the reaction product of I. A) at least one alkoxysilane group-containing monourethane A) of the formula 1
R.sub.n(OR.sup.1).sub.3-nSi—R.sup.2—NH—(C═O)—OR.sup.3   formula 1 wherein R.sub.n, R.sup.1, R.sup.2 and R.sup.3 independently of one another represent hydrocarbon radicals having 1-8 carbon atoms, wherein these may be linear, branched or cyclic or else may be integrated together to form a cyclic system, and n represents 0-2, and B) at least one diisocyanate B), in a molar ratio of A) to B) of from 1.0:1.5 to 1.0:0.6, optionally in the presence of at least one catalyst K), II. and the subsequent reaction C) with at least one diol and/or polyol C), optionally in the presence of at least one catalyst K), in the ratio of the NCO groups of reaction product I. to the OH groups of the diol and/or polyol II. C) of 1.0:1.5 to 1.0:0.6.

22-23. (canceled)

Description

EXAMPLES

[0111] Ingredients:

[0112] Vestanat® EP-UPMS: Trimethoxysilylpropyl methyl carbamate (Evonik Resource Efficiency GmbH)

[0113] Vestanat® IPDI: isophorone diisocyanate (Evonik Resource Efficiency GmbH)

[0114] Vestanat® EP Cat 11 B: tetraethylammonium benzoate in butanol (Evonik Resource Efficiency GmbH)

[0115] Tegoglide® 410: Glide and antiblocking additive based on a polyether siloxane copolymer (Evonik Resource Efficiency GmbH)

[0116] 1. Preparation

[0117] Alkoxysilane-functionalized and allophanate-functionalized urethane 1

[0118] I.

[0119] 36.9 g of Vestanat® EP-UPMS, 0.04 g of zinc(II) ethylhexanoate and 34.7 g of Vestanat® IPDI were charged to a three-necked flask with reflux condenser, blanketed with nitrogen and heated with stirring to 100° C. After heating for 12 hours, an NCO content of 9.33% was obtained.

[0120] II.

[0121] The resulting allophanate was cooled and 8.37 g of pentanediol and 0.01% dibutyltin dilaurate (DBTL) were added and stirred at 60-65° C. for 17 h until an NCO content of <0.1% was achieved, and after ca. 3 h 20 g of butyl acetate were added in order to lower the viscosity. The alkoxysilane-functionalized and allophanate-functionalized urethane 1 thus obtained is a clear liquid with a viscosity of 3457 mPas (at 23° C.).

[0122] Alkoxysilane-functionalized and allophanate-functionalized urethane 2

[0123] I.

[0124] 31.7 g of Vestanat® EP-UPMS, 0.04 g of zinc(II) ethylhexanoate and 29.8 g of Vestanat® IPDI were charged to a three-necked flask with reflux condenser, blanketed with nitrogen and heated with stirring to 100° C. After heating for 6 hours, an NCO content of 9.12% was obtained.

[0125] II.

[0126] The resulting allophanate was cooled and 13.5 g of dodecanediol and 0.01% dibutyltin dilaurate (DBTL) were added and stirred at 60-65° C. for several hours until an NCO content of <0.1% was achieved, then while still hot 20 g of 1-methoxypropyl-2-acetate were added in order to lower the viscosity. The alkoxysilane-functionalized and allophanate-functionalized urethane 2 thus obtained is a clear liquid with a viscosity of 1902 mPas (at 23° C.).

[0127] 2. Preparation of Clearcoat Materials from the Alkoxysilane-Functionalized and Allophanate-Functionalized Urethanes as Coating Compositions

[0128] For the formulation of the clearcoats according to the invention and the comparative examples, the components of the compositions shown in Table 1 and 2 were mixed together directly before processing.

[0129] The viscosity of the formulations, determined as the flow time in the DIN 4 cup at 23° C., was approximately 60 seconds.

TABLE-US-00001 TABLE 1 Composition of the inventive clearcoats of RT-curing systems Data in % by weight Item I II 1 Alkoxysilane-functionalized and allophanate- 91.24 functionalized urethane 1 2 Alkoxysilane-functionalized and allophanate- 99.0 functionalized urethane 2 3 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) 0.92 1.0 4 Tegoglide ® 410: 0.05 5 Xylene 7.79

[0130] Based on solid, 1.25% by weight DBU was used respectively.

TABLE-US-00002 TABLE 2 Composition of the inventive clearcoats of hot-curing systems Data in % by weight Item III IV 1 Alkoxysilane-functionalized and allophanate- 98.0 functionalized urethane 1 2 Alkoxysilane-functionalized and allophanate- 80.5 functionalized urethane 2 3 Vestanat ® EP-CAT 11 B component d) 2.0 1.6 4 1-Methoxypropyl-2-acetate 17.9

[0131] Based on solid, 1.25% by weight tetraethylammonium benzoate was used respectively.

[0132] Curing of the Clearcoats

[0133] To determine the mechanical characteristics, all coating materials were applied to phosphatized steel panels (Chemetall Gardobond 26S/60/OC) with a 100 μm doctor blade and cured at different baking conditions (RT is room temperature 23° C. Table 3; 22 minutes at 140° C., Table 4).

TABLE-US-00003 TABLE 3 Coating properties of the compositions I-II after curing at RT Composition I II Pendulum hardness (König) [s] 188 154 after 7 d Erichsen cupping [mm] 4 6 (EN ISO 1520) MEK test [ASTM D 4752] 150. >150 (Double rubs, 1 kg applied weight)

[0134] The coating properties of coatings I and II, which comprise the inventive alkoxysilane-functionalized and allophanate-functionalized urethanes 1 or 2, show high pendulum hardnesses and at the same time high flexibility (Erichsen cupping) at high MEK resistance.

TABLE-US-00004 TABLE 4 Coating properties of the compositions III-IV after curing at 140° C. (22 min) Composition III IV Pendulum hardness (König) [s] 203 177 after 1 d Erichsen cupping [mm] 0.5 1.0 (EN ISO 1520) MEK test [ASTM D 4752] >150 >150 (Double rubs, 1 kg applied weight)

[0135] The coating properties of coatings III and IV, which comprise the inventive alkoxysilane-functionalized and allophanate-functionalized urethanes 1 or 2, show high pendulum hardnesses and good chemical resistance.