USE OF SPECIFIC OPEN-CHAIN ETHER ISOCYANATES

Abstract

The invention relates to the use of at least one open-chain, optionally branched, ether isocyanate having an NCO functionality≥1, wherein 2 or 3 carbon atoms are present between at least one NCO group and at least one ether-oxygen atom, optionally in the presence of other reactants such as alcohols, amines, water, CO.sub.2, or of other reactants having an NCO functionality≥1, optionally in the presence of at least one catalyst, to increase the reaction speed and/or to reduce the optionally required catalyst amount during isocyanate modification. The invention further relates to a process for modifying isocyanates, to the modified isocyanates as such and to a two-component system or one-component system and to the moldings, coatings and composite parts obtainable therefrom.

Claims

1: In a process for increasing the reaction rate and/or reducing the optionally required amount of catalyst in isocyanate modification, the improvement comprising including at least one open-chain, optionally branched, ether isocyanate having an NCO functionality≥1, in which 2 or 3 carbon atoms are located between at least one NCO group and at least one ether oxygen atom, optionally in the presence of further coreactants such as alcohols, amines, water, CO.sub.2, or further isocyanates having an NCO functionality≥1, optionally in the presence of at least one catalyst.

2: The process as claimed in claim 1, characterized in that the at least one open-chain, optionally branched, ether isocyanate has an NCO functionality of 2 and 2 or 3 carbon atoms are located at least between one of the two NCO groups and the at least one ether oxygen atom.

3: The process as claimed in claim 1, characterized in that at least one further coreactant selected from the group consisting of alcohols, amines, water, CO.sub.2 and further isocyanates having an NCO functionality≥1 that do not contain an ether group is present.

4: The process as claimed in claim 1, characterized in that between 1% and 99% by weight, based on the total amount of compounds that have NCO groups, of the at least one open-chain, optionally branched, ether isocyanate is used, the balance to 100% consisting of one or more further isocyanates having an NCO functionality≥1.

5: The process as claimed in claim 4, characterized in that the amount of the at least one open-chain, optionally branched, ether isocyanate is between 50% and 90% by weight.

6: The process as claimed in claim 1, characterized in that modified isocyanates having a urethane, urea, biuret, dimer, isocyanurate, iminooxadiazinedione and/or carbodiimide structure are produced from the at least one open-chain, optionally branched, ether isocyanate.

7: A process for modifying isocyanates, comprising the reaction of at least one open-chain, optionally branched, ether isocyanate having an NCO functionality≥1, in which 2 or 3 carbon atoms are located between at least one NCO group and at least one ether oxygen atom, optionally in the presence of further coreactants selected from the group consisting of alcohols, amines, water, CO.sub.2, and further isocyanates having an NCO functionality≥1.

8: A modified isocyanate produced by the process as claimed in claim 7.

9: A two-component system containing a component A), comprising at least one modified isocyanate based on an open-chain, optionally branched, ether isocyanate having an NCO functionality≥1, in which 2 or 3 carbon atoms are located between at least one NCO group and at least one ether oxygen atom, and a component B), comprising at least one NCO-reactive compound.

10: The two-component system as claimed in claim 9, wherein the at least one NCO-reactive compound is a polyhydroxy compound, selected from the group consisting of a polyether polyol, a polyester polyol, a polycarbonate polyol, and a polyacrylate polyol.

11: A one-component system comprising at least one modified isocyanate based on an open-chain produced according to claim 1, optionally branched, ether isocyanate having an NCO functionality≥1, in which 2 or 3 carbon atoms are located between at least one NCO group and at least one ether oxygen atom, the free NCO groups of which have been deactivated with one or more blocking agents.

12: A shaped body or coating obtainable or produced by curing a two-component system as claimed in claim 9, optionally under the action of heat and/or in the presence of a catalyst.

13: A composite component comprising a material joined at least to a shaped body or a coating as claimed in claim 12 at least in part.

Description

EXAMPLES

[0054] All percentages, unless noted otherwise, are to be understood to mean percent by weight.

[0055] Mol % data were determined by .sup.1H NMR spectroscopy and always relate, unless noted otherwise, to the sum total of the NCO conversion products. The measurements were conducted on the Bruker DPX 400 or DRX 700 instruments on approx. 5% (H NMR) or approx. 50% (.sup.13C NMR) samples in dry C.sub.6D.sub.6, unless noted otherwise, at 400 or 700 MHz (H NMR) or 100 or 176 MHz (.sup.13C NMR).

[0056] The reference employed for the ppm scale was tetramethylsilane in the solvent with .sup.1H NMR chemical shift 0 ppm. Alternatively, C.sub.6D5H present in the NMR solvent was used as reference signal (7.15 ppm, .sup.1H-NMR), or the solvent signal itself (average signal of the 1:1:1 triplet at 128.0 ppm in the .sup.13C NMR. .sup.15N-NMR chemical shifts were indirectly determined by means of .sup.1H-.sup.15N-HMBC measurements, where external reference was made to (liquid) ammonia (0 ppm).

[0057] Dynamic viscosities were determined at 23° C. using the MCR 501 rheometer (from Anton Paar) in accordance with DIN EN ISO 3219:1994-10. Measurement at different shear rates ensured that Newtonian flow behavior can be assumed. Details regarding the shear rate can therefore be omitted.

[0058] The NCO content was determined by titration in accordance with DIN EN ISO 10283:2007-11.

[0059] The residual monomer content was determined by gas chromatography in accordance with DIN EN ISO 10283:2007-11 with internal standard.

[0060] GC-MS was performed using the Agilent GC6890, equipped with an MN 725825.30 Optima-5 MS Accent capillary column (30 m, 0.25 mm internal diameter, 0.5 μm film layer thickness) and a 5973 mass spectrometer as detector with helium as transport gas (flow rate of 2 ml/min). The column temperature was initially 60° C. (2 min) and was then increased gradually by 8K/min to 360° C. The GC-MS detection used electron impact ionization with 70 eV ionization energy. The injector temperature chosen was 250° C.

[0061] Size exclusion chromatography (SEC) was performed in accordance with DIN 55672-1:2016-03 with tetrahydrofuran as eluent.

[0062] X-ray crystal structure analysis took place on an Oxford Diffraction Xcalibur equipped with a CCD area detector (Ruby model), a Cu.sub.K,α source and Osmic mirrors as monochromator at 106-107 K. The program CrysAlis Version 1.171.38.43 (Rigaku 2015) was used for data acquisition and reduction. SHELXTL Version 6.14 (Bruker AXS, 2003) was used for structural resolution.

[0063] The Hazen color number was measured by spectrophotometry in accordance with DIN EN ISO 6271-2:2005-03 using a LICO 400 spectrophotometer from Lange, Germany.

[0064] All reactions were conducted under a nitrogen atmosphere in glass apparatuses dried beforehand under reduced pressure at 150-200° C.

[0065] The diisocyanates used are products from Covestro. All other commercially available chemicals were obtained from Aldrich, D-82018 Taufkirchen.

[0066] Production of Starting Materials for Experiments According to the Invention and Comparative Experiments:

[0067] A) Production of 4-methoxy-1-butanamine

[0068] 2(4-Methoxybutyl)-1H-isoindole-1.3(211)dione

[0069] 1.4 liters of DMF, 352 g of phthalimide and 780 g of cesium carbonate were initially charged into a 4 liter four-necked flask and 400 g of 1-bromo-4-methoxybutane were added dropwise with stirring at 70° C. The reaction mixture was kept at this temperature for four hours, cooled and then introduced into ice water with stirring. The product precipitates in crystalline form, is filtered off, rinsed on the filter with water and subsequently dried under reduced pressure. 519.1 g (93% of theory)

4-Methoxy-1 butanamine

[0070] 520 g of 2-4-methoxybutyl)-1˜isoindole-1,3(2hydrazine and 167 g of hydrazine monohydrate in methanol were initially charged into a 4 liter four-necked flask and stirred under reflux for two hours.

[0071] The solution was cooled and 3% aqueous HCl solution was added with stirring.

[0072] The precipitating solids were filtered off and disposed of. The mother liquor was made strongly alkaline with 200 ml of 50% NaOH solution and the product was extracted with diethyl ether. After drying with magnesium sulfate, concentration and distillation were performed. 295 g (79% of theory)

[0073] B) Production of the ether isocyanates and comparative compounds having an NCO function

[0074] In each case a mixture consisting of 2 mol of isophorone diisocyanate and 2 mol of Desmodur® 2460 M (mixture of 4,4′- and 2,4′-diphenylmethane diisocyanate) were initially charged into a 1 liter four-necked flask with effective magnetic stirrer, dropping funnel with pressure equalization, internal temperature control, attached 40 cm-long Vigreux column and adjoining dephlegmator, and 1 mol of the monoamine to be converted to the respective isocyanate were weighed into the dropping funnel with pressure equalization. With stirring, the initially charged diisocyanate was subsequently brought to an internal temperature of 150-160° C. and the monoamine was rapidly added dropwise into the high-boiling diisocyanate mixture (exothermicity up to approx. 180° C.) and distillate that distills over was removed batchwise. Distillate was then removed by gradual reduction of the system pressure until the boiling temperature of the high-boiling diisocyanate mixture was achieved at the top.

[0075] The distillates thus obtained were subsequently fractionated in order to obtain the pure monoisocyanates 1-6 in 70-90% yields, based on the amine used.

TABLE-US-00001 TABLE 1 Monoisocyanates No. and formula B.p. (° C.) at p [mbar] n.sub.D.sup.20 1 CH.sub.3OCH.sub.2CH.sub.2NCO 68 120 1.4082 2 CH.sub.3OCH.sub.2C(H,CH.sub.3)NCO 67 92 1.4090 3 CH.sub.3OCH.sub.2CH.sub.2CH.sub.2NCO 73 80 1.4171 4 CH.sub.3CH.sub.2CH.sub.2CH.sub.2NCO 115 1013 1.4060 5 CH.sub.3CH.sub.2CH.sub.2C(H,CH.sub.3)NCO 71 153 1.4077 6 CH.sub.3OCH.sub.2CH.sub.2CH.sub.2CH.sub.2NCO 80 40 1.4242

[0076] The diisocyanates used in Examples 2 to 4 with ether function were produced analogously to the procedure from Example 1 of EP 0 764 633 A2.

Examples 1a to 1i Urethanization (1a to 1e: According to the Invention, 1f to 1i: Comparative Examples)

[0077] In each case 1.5 mol of n-butanol were heated to 50° C. with magnetic stirring in a 250 ml three-necked flask with septum for the metering of the respective isocyanate used, internal temperature control and reflux condenser, and then 0.1 mol of the respective monoisocyanate or 0.05 mol of the respective diisocyanate were quickly injected. Removal of the heating bath and—especially at the beginning of 1a—any necessary cooling with an ice bath allowed the internal temperature to be kept at 50° C.

[0078] The NCO content and thus the conversion was monitored titrimetrically at regular intervals. The time (t.sub.1/2) after which only 50% of the originally present NCO groups were present was used to compare the reactivity of the isocyanates used in the experiments according to the invention (1a to 1e) and the comparative experiments (1f to 1i), cf. Table 2.

TABLE-US-00002 TABLE 2 Urethanizations Example 1 Isocyanate used t.sub.1/2 [sec] a CH.sub.3OCH.sub.2CH.sub.2NCO 1740 b CH.sub.3OCH.sub.2C(H,CH.sub.3)NCO 3650 c CH.sub.3OCH.sub.2CH.sub.2CH.sub.2NCO 2200 d OCNCH.sub.2CH.sub.2OCH.sub.2CH.sub.2NCO  900 e OCNCH.sub.2CH.sub.2CH.sub.2OCH.sub.2CH.sub.2CH.sub.2NCO 2300 f CH.sub.3CH.sub.2CH.sub.2CH.sub.2NCO 2900 g CH.sub.3CH.sub.2CH.sub.2C(H,CH.sub.3)NCO 10 000 h CH.sub.3OCH.sub.2CH.sub.2CH.sub.2CH.sub.2NCO 2900 i OCNCH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2NCO 2500

[0079] As can readily be identified from the comparison of the t.sub.1/2 values, the structurally comparable isocyanates are always significantly more reactive in the presence of an ether oxygen atom in the 2 or 3 position than the counterparts having a CH.sub.2 group instead of oxygen. Even though isocyanate groups bound to secondary carbon atoms are generally less reactive than those bound to primary carbon atoms, the comparison of the results from Example 1b (according to the invention) with Example 1g (comparative) shows that a considerable activation of the NCO group with respect to the urethanization reaction is also able to be recorded here. This effect is more pronounced in the case of the O—C—C—NCO-linked derivatives than in the case of those having 3 carbon atoms between the NCO group and the next oxygen atom in the chain. In the case of the latter, however, said effect is still clearly apparent, but no longer occurs when a further CH.sub.2 unit is incorporated (Ex. 1h, comparative).

Examples 2a and 2b Trimerization (2a: According to the Invention, 2b: Comparative Example)

[0080] In a 100 ml three-necked flask with septum for the metering of the catalyst, internal temperature control and reflux condenser, with magnetic stirring, 39 g (386 mmol) of 2-methoxyethyl isocyanate 1 (Example 2a, according to the invention) or 38.2 g (386 mmol) of n-butyl isocyanate 5 (Example 2b, comparative) were admixed at 60° C. dropwise with a 50% solution of 5-azoniaspiro[4.5]decanium hydrogendifluoride in 2-propanol.

[0081] In Example 2a according to the invention, after addition of a total of 23 mg of catalyst solution and short incubation time, a strongly exothermic reaction began which was able to be limited to a maximum of 70° C. by cooling with an ice bath. After 50 min approx. 50% of the 1 used had been converted into a mixture of isocyanurate and iminooxadiazinedione. In the further course of reaction, further monomer conversion was able to be recorded without additional catalyst addition. Crystallization began after distillative removal of the unconverted monomer 1. Recrystallization from methylene chloride/n-hexane yielded single crystals, m.p.: 45° C., which were identified by means of X-ray crystal structure analysis as N,N′,N″-tris(2-methoxyethyl) isocyanurate (isocyanurate-type trimer from 1).

[0082] In Comparative Example 2b, significantly more catalyst solution was required (28 mg), the conversion thus achievable after approx. 45 min was only 14% and then increased only very slowly without further catalyst addition. The temperature increase during the reaction was also significantly more moderate. The N,N′,N″-tris(n-butyl) isocyanurate isolated distillatively after monomer removal, b.p. 120° C./0.01 mbar, was obtained as a slightly viscous liquid that does not crystallize even after storage in a refrigerator.

[0083] These investigations prove, on the one hand, the significantly increased reactivity of the open-chain, optionally branched, ether isocyanates according to the invention, such as 1, even in NCO—NCO reactions on the one hand and, on the other hand, that the replacement of a methylene group in 5 by an oxygen atom (1) surprisingly results in products having significantly different physical properties—here the melting point.

Examples 3a, b and c Trimerization (3a and b: According to the Invention, 3c: Comparative Example)

[0084] In a 1 liter three-necked flask with septum for the metering of the catalyst, internal temperature control and reflux condenser, with mechanical stirring, 500 g (3.2 mol) of bis(2-isocyanatoethyl) ether (Example 3a, according to the invention), 590 g (3.2 mol) of bis(3-isocyanatpropyl) ether (Example 3b, according to the invention) or 494 g (3.2 mol) of pentamethylene diisocyanate (Example 2c, comparative) were admixed at 60° C. dropwise with “isooctyl phobane” (isomer mixture, consisting of 9-(2,4,4-trimethylpentyl)-9-phosphabicyclo[3.3.1]nonane and 9-(2,4,4-trimethylpentyl)-9-phosphabicyclo[4.2.1]nonane) until a slight exothermicity and a continuous decrease in the NCO content was able to be recorded.

[0085] In Examples 2a and 2b according to the invention, after addition of a total of 846 mg and 956 mg, respectively, of catalyst (0.1 and 0.12 mol %, respectively, based on the catalyst and diisocyanate used), this effect began. By occasionally removing the external heat source, the reactions were able to be performed in a readily controllable manner at approx. 60° C. In Comparative Example 3c, 12.2 g of catalyst (1.5 mol %, based on the catalyst and diisocyanate used) were necessary for this purpose. Over the course of 4 to 5 hours, the NCO contents of the mixtures had decreased by approx. 20% in each case. After the catalyst had been deactivated by addition of elemental sulfur (1.1 equivalents based on the catalyst), stirring for a further thirty minutes at 60° C. and subsequent distillative monomer removal, the result in Examples 3a and 3b according to the invention was light-colored (<50 APHA), viscous resins; the product from Comparative Example 3c exhibited, due to the significantly higher catalyst consumption, a significantly higher color number (120 APHA). The further data can be found in Table 3.

TABLE-US-00003 TABLE 3 Trimerizations NCO content Viscosity Example 3 Diisocyanate used [%] [mPas]* a OCNCH.sub.2CH.sub.2OCH.sub.2CH.sub.2NCO 14.2**  3840** b OCNCH.sub.2CH.sub.2CH.sub.2OCH.sub.2CH.sub.2CH.sub.2NCO 19.5 1360 c OCNCH.sub.2CH.sub.2CH.sub.2CH.sub.2CH.sub.2NCO 23.5 5480 *at 23° C. **80% solution in butyl acetate, the 100% resin is of extremely high viscosity

[0086] These investigations likewise prove the significantly increased reactivity of the specific open-chain, optionally branched, ether isocyanates and, on the other hand, that the replacement of a methylene group by an oxygen atom also in diisocyanate conversion products results in products having significantly different physical properties—here in particular in Example 3a the viscosity.

Example 4: Trimerization

[0087] In a 4 liter three-necked flask with dropping funnel with pressure equalization for the metering of the catalyst, internal temperature control and reflux condenser, with mechanical stirring, 2700 g (14.7 mol) of an isomer mixture obtained in accordance with EP 0 764 633 A2, Example 1 (therein as “dipropylene glycol diisocyanate, isomer mixture”) were admixed at 60° C. dropwise with a total of 15.9 g of a 10% solution of benzyltrimethylammonium hydroxide in 2-ethyl-1,3-hexanediol such that, with moderate exothermicity, a continuous decrease in the NCO content was able to be recorded.

[0088] Over the course of approx. 6 hours, the NCO content had fallen from initially 45.4% to 36.6%. The reaction was concluded by addition of 2.1 g of di-n-butyl phosphate so as to deactivate the catalyst and, after stirring for a further thirty minutes at 60° C. and subsequent distillative monomer removal, the result was 900 g of a highly viscous (48 Pas), clear, virtually colorless polyisocyanate resin having an NCO content of 19.2%.