POLYISOCYANURATE PLASTIC CONTAINING SILOXANE GROUPS AND METHOD FOR PRODUCTION THEREOF

Abstract

The invention relates to novel polyisocyanurate plastics containing siloxane groups, which are obtainable by a method comprising the following steps: al) providing a composition A), which contains i) oligomeric polyisocyanates B) and compounds containing silicon C) or ii) contains oligomeric silicon-modified polyisocyanates D); or iii) contains oligomeric silicon-modified polyisocyanates D) and oligomeric polyisocyanates B); or iv) contains oligomeric polyisocyanates B), compounds containing silicon C) and modified oligomeric polyisocyanates D); or v) contains compounds containing silicon C) and silicon-modified, oligomeric polyisocyanates D); a2) catalytic trimerization of the composition A); wherein the composition A) has a content of monomer diisocyanates of 20 wt % at maximum. The invention further relates to the method by which the polyisocyanurate plastics according to the invention are obtainable, to the use of the polyisocyanurate plastics according to the invention for producing coatings, films, semi-finished products, and molded parts, and to substrates coated by such a coating.

Claims

1.-20. (canceled)

21. A polyisocyanurate plastic containing siloxane groups, obtainable by a process comprising the steps of: a1) providing a composition A) which i) contains oligomeric polyisocyanates B) and silicon-containing compounds C); or ii) contains oligomeric silicon-modified polyisocyanates D); or iii) contains oligomeric silicon-modified polyisocyanates D) and oligomeric polyisocyanates B); or iv) contains oligomeric polyisocyanates B), silicon-containing compounds C) and modified oligomeric polyisocyanates D); or v) contains silicon-containing compounds C) and silicon-modified, oligomeric polyisocyanates D); a2) catalytic trimerization of the composition A); wherein the composition A) has a content of monomeric diisocyanates of not more than 20% by weight.

22. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the silicon-containing compounds C) has at least one isocyanate-reactive functional group.

23. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the silicon-containing compounds C) are selected from the group consisting of oligomeric silicon-modified polyisocyanates D), aminosilanes E), silane-functional aspartic esters F), silane-functional alkylamides G), mercaptosilanes H), isocyanatosilanes I) and mixtures thereof.

24. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the silicon-containing compounds C) and the oligomeric silicon-modified polyisocyanates D) comprise at least one structural unit selected from the group consisting of: a) a structural unit of formula (I) ##STR00017## where R.sup.1, R.sup.2 and R.sup.3 are identical or different radicals and are each a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having 1 to 18 carbon atoms, which may optionally contain 1 to 3 heteroatoms from the series of oxygen, sulfur and nitrogen, X is a linear or branched organic radical which has at least 1 carbon atom and may optionally contain 1 to 2 imino groups (NH), and R.sup.4 is hydrogen, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having 1 to 18 carbon atoms or a radical of the formula ##STR00018## in which R.sup.1, R.sup.2, R.sup.3 and X are as defined above; b) a structural unit of formula (II) ##STR00019## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), X is a linear or branched organic radical having at least 1 carbon atom and R.sup.5 and R.sup.6 are independently 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; c) a structural unit of formula (III) ##STR00020## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), X is a linear or branched organic radical having at least 1 carbon atom and R.sup.9 is a saturated linear or branched, aliphatic or cycloaliphatic organic radical having 1 to 8 carbon atoms; d) a structural unit of formula (IV) ##STR00021## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I) and Y is a linear or branched organic radical having at least 1 carbon atom; and e) a structural unit of formula (V) ##STR00022## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), and Y is a linear or branched organic radical having at least 1 carbon atom.

25. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that said plastic comprises alkoxysiloxane groups, the silicon-containing compounds C) are alkoxysilyl-containing compounds C) and the oligomeric silicon-modified polyisocyanates D) are oligomeric polyisocyanates D) modified with alkoxysilyl groups.

26. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the silicon-containing compounds C) and the oligomeric silicon-modified polyisocyanates D) comprise at least one structural unit selected from the group consisting of: a) a structural unit of formula (I) ##STR00023## where R.sup.1, R.sup.2 and R.sup.3 are each methyl, methoxy and/or ethoxy, with the proviso that at least one of the radicals R.sup.1, R.sup.2 and R.sup.3 is such a methoxy or ethoxy radical, X is a propylene radical (CH.sub.2CH.sub.2CH.sub.2), and R.sup.4 is hydrogen, a methyl radical or a radical of formula ##STR00024## in which R.sup.1, R.sup.2, R.sup.3 and X are as defined above; b) a structural unit of formula (II) ##STR00025## where R.sup.1, R.sup.2, R.sup.3 and X wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), R.sup.5 and R.sup.6 are identical or different radicals and are a methyl-, ethyl-, n-butyl- or 2-ethylhexyl radical; c) a structural unit of formula (III) ##STR00026## where R.sup.1, R.sup.2, R.sup.3 and X wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), R.sup.9 is hydrogen; d) structural unit of formula (IV) ##STR00027## where R.sup.1, R.sup.2 and R.sup.3 wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), Y is a propylene radical (CH.sub.2CH.sub.2CH.sub.2); and e) a structural unit of formula (V) ##STR00028## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined for formula (I), and Y is a linear or branched organic radical having at least 1 carbon atom.

27. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the oligomeric polyisocyanates B) or the oligomeric, silicon-modified polyisocyanates D) are selected from at least one oligomeric polyisocyanate having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione or oxadiazinetrione structure or mixtures thereof.

28. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the oligomeric polyisocyanates B) or the oligomeric, silicon-modified polyisocyanates D) consist of one or more oligomeric polyisocyanates formed from 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate or 4,4-diisocyanatodicyclohexylmethane or mixtures thereof.

29. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the catalytic trimerization is carried out in the presence of a trimerization catalyst L), wherein the trimerization catalyst L) preferably comprises at least one alkali metal or alkaline earth metal salt.

30. The polyisocyanurate plastic containing siloxane groups as claimed in claim 29, characterized in that the trimerization catalyst L) comprises potassium acetate as the alkali metal salt.

31. The polyisocyanurate plastic containing siloxane groups as claimed in claim 29, characterized in that the trimerization catalyst L) comprises a polyether, in particular a polyethylene glycol.

32. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that the composition A) has a content of monomeric diisocyanates of not more than 15% by weight, not more than 10% by weight or not more than 5% by weight, based in each case on the weight of the composition A).

33. The polyisocyanurate plastic containing siloxane groups as claimed in claim 21, characterized in that it constitutes a highly converted polyisocyanurate plastic containing siloxane groups in which not more than 20% of the isocyanate groups originally contained in the composition A) have been preserved.

34. The use of a polyisocyanurate plastic containing siloxane groups as claimed in claim 21 for producing coatings, films, semifinished products and moldings.

35. coating, film, semifinished product or molding containing a polyisocyanurate plastic containing siloxane groups as claimed in claim 21.

36. A substrate coated with a coating as claimed in claim 35, wherein the substrate may in particular be selected from a vehicle body, in particular a goods vehicle or motor vehicle body, and electronic entertainment devices, such as laptops, tablets or mobile phones.

37. A process for producing a polyisocyanurate plastic containing siloxane groups comprising the steps of: a1) providing a composition A) which i) contains oligomeric polyisocyanates B) and silicon-containing compounds C); or ii) contains oligomeric silicon-modified polyisocyanates D); or iii) contains oligomeric silicon-modified polyisocyanates D) and oligomeric polyisocyanates B); or iv) contains oligomeric polyisocyanates B), silicon-containing compounds C) and modified oligomeric polyisocyanates D); or v) contains silicon-containing compounds C) and silicon-modified, oligomeric polyisocyanates D); a2) catalytic trimerization of the composition A); wherein the composition A) has a content of monomeric diisocyanates of not more than 20% by weight.

38. The process as claimed in claim 37, characterized in that the catalytic trimerization is carried out in the presence of a trimerization catalyst L) which is defined as in claim 29.

39. The process as claimed in claim 37, characterized in that the silicon-containing compounds C) and/or the oligomeric, silicon-modified polyisocyanates D) are defined as in claim 22 and/or in that the composition A) is defined as in claim 32.

40. The process as claimed in claim 37, characterized in that the catalytic trimerization is continued at least up to a degree of conversion at which only not more than 20% of the isocyanate groups originally contained in the composition A) remain present, so that a highly converted polyisocyanurate plastic containing siloxane groups is obtained.

Description

EXAMPLES

1. Methods

[0184] All reported percentages are based on weight unless otherwise stated.

[0185] The NCO contents were determined by titrimetry to DIN EN ISO 11909.

[0186] OH numbers were determined by titrimetry to DIN 53240-2: 2007-11, acid numbers to DIN 3682 5. The OH contents reported were calculated from the OH numbers determined by analysis.

[0187] The residual monomer contents were measured in accordance with DIN EN ISO 10283 by gas chromatography with an internal standard.

[0188] All viscosity measurements were taken with a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) according to DIN EN ISO 3219/A3.

[0189] Pendulum damping: Pendulum damping is measured to DIN EN ISO 1522 on a glass plate and is determined according to K?nig.

[0190] Solvent resistance: For this purpose, a small amount of the relevant solvents (xylene, 1-methoxyprop-2-yl acetate, ethyl acetate or acetone) was added to a test tube and provided with a cotton pad at the opening, so that an atmosphere saturated with solvent was formed inside the test tube. The test tubes were subsequently placed with the cotton pad on the lacquer surface where they remained for 5 minutes. Once the solvent had been wiped off, the film was examined for destruction/softening/loss of adhesion (0=no change, 5=film destroyed).

[0191] Hammer test with steel wool (dry scratching):

[0192] A hammer (weight: 800 g without handle) covered with 00 steel wool on its flat side was cautiously placed onto the coated surface at right angles and guided over the coating in a trace without tipping and without additional physical force. 50 back-and-forth strokes were conducted in each case. After being subjected to the scratching medium, the test surface was cleaned with a soft cloth and subsequently the haze in comparison to the value before the scratching was determined according to ASTM D1003 with a BYK-Gardner Haze Gard Plus instrument.

2. Materials

Example 1

[0193] Production of a Polyisocyanate Having Alkoxysilyl Groups:

[0194] In a flask fitted with a thermometer, KPG stirrer, reflux cooler and dropping funnel 536.2 g of Desmodur? N 3900 [Covestro AG, D, low-monomer polyisocyanurate polyisocyanate based on hexamethylene diisocyanate (HDI), NCO content: 23.5%; viscosity (23? C.): 750 mPas, content of monomeric HDI?0.25%] and 91 mg of zinc trifluoromethanesulfonate were initially charged under a nitrogen atmosphere and heated to 100? C. At this temperature, over the course of 1 h, 373.1 g of N-(3-trimethoxysilylpropyl)formamide (1.8 mol, prepared as per example 1 of WO 2015/113919 A1) were added dropwise. Stirring was continued at 100? C. for a further 3 hours until the free NCO group content had dropped to 4.8%. The batch was admixed with 114 g of butyl acetate and 114 g of solvent naphtha 100 and cooled to room temperature.

[0195] A clear solution was obtained.

[0196] NCO content 4.4%

[0197] Si content: 4.4%

[0198] Solids content 80%

[0199] Viscosity (23? C., shear gradient D=250 l/s) 1030 mPas.

Example 2

[0200] Production of a Polyisocyanate Having Alkoxysilyl Groups

[0201] Based on a working example in WO 2012/168079 (curing agent system VB2-1), by reaction of 100 parts by weight of Desmodur N 3300 (low-monomer polyisocyanurate polyisocyanate based on HDI, NCO content: 21.6%; average NCO functionality: 3.5; viscosity (23? C.): 3200 mPas, content of monomeric HDI?0.25%) with a mixture of 30 parts by weight of bis-[3-(trimethoxysilyl)propyl]amine and 21 parts by weight of N-[3-(trimethoxysilyl)propyl]butylamine in 84 parts by weight of butyl acetate at 50? C., a partially silanized HDI trimerizate was produced. After a reaction time of approximately four hours, the characteristics found for the present solution were as follows:

[0202] NCO content: 6.0%

[0203] Si content: 3.2%

[0204] Solids content: 64%

[0205] Viscosity (23? C., shear gradient D=100 l/s): 70 mPas.

Example 3

[0206] Mixing of an Alkoxysilyl-Functional Diurethane with a Polyisocyanate

[0207] 100 g of VESTANAT? EP-M 95 [Evonik Industries, DE; solvent-free, trimethoxysilyl-containing crosslinker, produced according to the teaching of WO 2014/180623 (table 1) by reaction of 2 mol of 3-isocyanatopropyltrimethoxysilane with 1 mol of 1,9-nonanediol] were mixed with 200 g of Desmodur? N 3600 [Covestro AG, DE, low-monomer polyisocyanurate polyisocyanate based on hexamethylene diisocyanate (HDI), NCO content: 23.0%; viscosity (23? C.): 1200 mPas, content of monomeric HDI ? 0.25%] with exclusion of moisture at room temperature.

[0208] NCO content: 15.3%

[0209] Si content: 3.3%

[0210] Solids content: 100%

[0211] Viscosity (23? C., D=100 l/s): 1300 mPas

Example 4

[0212] Production of a Polyisocyanate Having a Alkoxysilyl Groups

[0213] 756 g (4.5 mol) of hexamethylene diisocyanate (HDI) were introduced under dry nitrogen with stirring at a temperature of 80? C. and 0.1 g of zinc(II) 2-ethyl-1-hexanoate as catalyst were added. Over a period of about 30 minutes, 294 g (1.5 mol) of mercaptopropyltrimethoxysilane were added dropwise, the temperature of the mixture rising to up to 85? C. owing to the exothermic reaction. Stirring of the reaction mixture was continued at 85? C. until, after about 2 hours, the NCO content had dropped to 34.9%. The catalyst was deactivated by addition of 0.1 g of orthophosphoric acid and the unreacted monomeric HDI was removed in a thin-film evaporator at a temperature of 130? C. and a pressure of 0.1 mbar. This gave 693 g of a virtually colorless, clear polyisocyanate mixture having the following characteristics and composition:

[0214] NCO content: 11.8%

[0215] Si content: 6.1%

[0216] Monomeric HDI: 0.06%

[0217] Viscosity (23? C., shear gradient D=100 l/s): 452 mPas

[0218] Thiourethane: 0.0 mol %

[0219] Thioallophanate: 99.0 mol %

[0220] Isocyanurate groups: 1.0 mol %.

[0221] Catalysts

[0222] Cat.1: Production of a Catalytic Potassium Acetate 18-Crown-6 Solution in Diethylene Glycol

[0223] 1.77 g of potassium acetate (Sigma Aldrich), 4.75 g of the crown ether 18-crown-6 from Merck KGaA and 31.15 g of diethylene glycol from Sigma Aldrich were weighed in and stirred for several hours until a clear solution was formed.

[0224] Cat. 2: Tetrabutylammonium Benzoate (TBAB)

[0225] TBAB (tetrabutylammonium benzoate from Sigma Aldrich) was used as a 10% solution in MPA (1-methoxy-2-propyl acetate; 1,2-propylene glycol monomethyl ether acetate).

[0226] Use Example:

[0227] The coating compositions were produced by initially charging the polyisocyanates having alkoxysilyl groups/the mixture according to example 3 and subsequently adding the respective catalyst solutions. Stirring was carried out using a Speed Mixer (Hausschild Engineering, type DAC 150.1 FVZ) at 2750 rpm for 1 min. The clearcoats were subsequently applied to a glass sheet using a 100 ?m film casting frame (Byk Gardner) and dried in a recirculating air drying cabinet for 10 minutes at 140? C. After cooling (10 min RT) the films were subjected to visual assessment and the first K?nig pendulum damping measurements were taken.

TABLE-US-00001 Comparison Inventive Comparison Inventive Example 5 6 7 8 Product according to example 4 30.00 g 30.00 g 30.00 g 30.00 g Cat. 1 0.94 g 0.94 g Cat. 2 1.50g 1.50g Total amount of product + catalyst 30.00g 30.94g 31.50g 32.44g Curing: 10 min, 140? C. Coating appearance clear, wet clear, dry clear, dry clear, dry but rubbery, scrapeable Pendulum immediately measurable 14 s not 13 s damping measurable after 1 d RT 17 s 20 s after 3 d RT 17 s 18 s after 7 d RT 45 s 22 s after 14 d RT 70 s 30 s Solvent xylene 1 0 resistance 1-methoxyprop-2-yl 1 0 after 5 min.; acetate sheets after ethyl acetate 2 2 14 d RT acetone 2 2 = not measured

[0228] To verify the completeness of the NCO reaction the NCO reduction was investigated by IR spectroscopy for the compositions according to examples 6 and 8.

[0229] The coating compositions were produced by weighing in the silane-modified polyisocyanates with the catalysts and their mixtures and subsequently stirring in the Speed Mixer (Hausschild Engineering, type DAC 150.1 FVZ) at 2750 rpm for 1 min.

TABLE-US-00002 Composition according to example 6 8 Integration or NCO (2380-2170) cm.sup.?1 Liquid 100% 100% Dry, immediately 1% 1% after curing

[0230] The test lacquers were analyzed directly (wet lacquer) with an FT-IR spectrometer (Tensor 11 with platinum ATR unit (diamond crystal) from Bruker). The clearcoat was subsequently applied to a glass sheet using a 100 ?m film casting frame and dried in a recirculating air drying cabinet for 10 minutes at 140? C. and then immediately after the baking removed as a clearcoat film and reanalyzed.

[0231] The isocyanate reaction is characterized by tracking the intensity of the NCO peak (using an integration in the wavenumber range of 2380-2170 cm.sup.?1), wherein the first measurement of the wet lacquer material after mixing of the components is set to 100% as the starting value. All further measurements (after application, thermal treatment and/or storage) are then calculated relative to the starting value (ratio formation).

[0232] In the measurement on an ATR crystal the intensity of the spectrum is dependent on the penetration depth of the IR beam into the material to be measured and on the covering of the crystal surface. This penetration depth is in turn dependent on the refractive index of the material. Since the refractive index of the wet lacquer differs from the refractive index of the baked clearcoat film and a comparable covering of the crystal surface cannot be ensured for different measurements (on the wet lacquer/on the clearcoat) the ratio calculation must include a correction of both effects by virtue of all spectra being normalized to the CH stretching vibration peak (wavenumber range 3000-2800 cm.sup.?1).

[0233] Examples 6 and 8 (inventive) show, in contrast to the comparative examples 5 and 7 that, the trimerization reaction starts only when the catalyst cat. I is present. The IR measurements verify the virtually complete conversion of the NCO groups. Subsequent post-curing upon storage must then be ascribed to the second curing mechanism of the alkoxysilyl groups. Without catalyst (5) or only with a catalyst (7) which catalyzes the hydrolysis/condensation of alkoxysilyl groups at the chosen temperature, no cured films are produced.

TABLE-US-00003 Inventive Inventive Inventive Inventive Example 8 9 10 11 Product according to example 4 30.00 g Product according to example 1 30.00 g Product according to example 2 30.00 g Product according to example 3 30.00 g Cat. 1 0.94 g 0.94 g 0.94 g 0.94 g Cat. 2 1.50g 1.50g 1.50g 1.50g Total amount of product + catalyst 32.44g 32.44g 32.44g 32.44g Curing: 10 min, 140? C. Coating appearance clear, dry clear, dry clear, dry clear, dry Pendulum damping immediately 13 s 24 s 24 s 63 s after 1 d RT 20 s 112 s 70 s 78 s after 3 d RT 18 s 166 s 155 s 161 s after 7 d RT 22 s 173 s 184 s 176 s after 14 d RT 30 s 180 s 195 s 184 s Solvent resistance xylene 0 0 1 1 after 5 min.; sheets 1-methoxyprop-2-yl 0 0 1 1 after 14 d RT acetate ethyl acetate 2 1 2 2 acetone 2 2 2 2

[0234] Examples 8 to 11 show that the properties of the inventive polyisocyanurate plastics can be varied with respect to hardness and solvent resistance.

[0235] The scratch resistance of the coated glass sheets stored for 21 days according to examples 6, 8, 9, 10 and 11 in comparison with a two component polyurethane lacquer was tested. As comparative example 12, 49.06 g of Setalux? D A 665 BA/X, 65% in butyl acetate/xylene (3:1) (polyacrylate polyol from Nuplex, DE) and 0.50 g of BYK-331, 10% in 1-methoxyprop-2-yl acetate (flow assistant from BYK, DE), were mixed with 16.56 g of Desmodur? N 3300 using a Speed Mixer (Hausschild Engineering, type DAC 150.1 FVZ) at 2750 rpm for 1 min. The clearcoat was subsequently applied to to a glass sheet using a 100 ?m film casting frame (Byk Gardner) and dried in a recirculating air drying cabinet for 30 minutes at 140? C. The lacquer according to comparative example 12 was likewise stored for 21 days at RT.

[0236] The determination of scratch resistance by means of the hammer test gave the following values:

TABLE-US-00004 Example 6 8 9 10 11 12 In- In- In- In- In- Com- ventive ventive ventive ventive ventive parison Delta 122 92 60 81 139 216 haze

[0237] The inventive examples exhibit a smaller increase in haze upon scratching with steel wool than the comparison.