AMINE CATALYSTS FOR THE MANUFACTURE OF ISOCYANURATE POLYMERS

Abstract

The present invention relates to the use of tertiary amines as catalysts for the cross-linking of isocyanate groups which are aliphatically and/or cyclo-aliphatically bonded. The catalysts according to the invention have the particular advantage that they are thermally latent.

Claims

1. A polymerizable composition comprising a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bonded isocyanate groups; and b) at least one compound of formula (I) ##STR00009## wherein R.sup.1 and R.sup.2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl, and unbranched C7-alkyl; R.sup.5 is selected from the group consisting of propylene, butylene, pentylene, and a radical of formula (II), preferably from butylene and the radical of formula (II); ##STR00010## wherein A in formula (II) is selected from the group consisting of O, S, and NR.sup.3, wherein R.sup.3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, and isobutyl; and B is independently of A selected from the group consisting of OH, SH, NHR.sup.4, and NH.sub.2, wherein R.sup.4 is selected from the group consisting of methyl, ethyl, and propyl; wherein a ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:1 and at least 80% of the isocyanate groups present in the polymerizable composition are aliphatically, cycloaliphatically, or araliphatically bonded.

2. The polymerizable composition as claimed in claim 1, wherein in formula (II) A is NR.sup.3 and R.sup.3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, and isobutyl.

3. The polymerizable composition as claimed in claim 2, wherein R.sup.1, R.sup.2, and R.sup.3 are methyl and B is OH.

4. The polymerizable composition as claimed in claim 1, wherein in formula (II) A is oxygen.

5. The polymerizable composition as claimed in claim 4, wherein R.sup.1 and R.sup.2 are methyl and B is OH.

6. The polymerizable composition as claimed in claim 1, wherein in formula (I) R.sup.5 is butylene.

7. The use of a compound of formula (I) as defined in any of claim 1 as a catalyst for crosslinking of at least two aliphatically and/or cycloaliphatically bonded isocyanate groups.

8. The use as claimed in claim 7, wherein the use results in a highly crosslinked polymer.

9. The use as claimed in claim 7, wherein at least one polyisocyanate selected from the group consisting of HDI, PDI, IPDI, H12MDI, oligomerized HDI, oligomerized PDI, oligomerized H12MDI, and oligomerized IPDI is employed.

10. A kit containing a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bonded isocyanate groups and b) at least one compound of formula (I) as defined in claim 1.

11. A process for producing a polymer comprising a) mixing at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bonded isocyanate groups with a compound of formula (I) as defined in claim 1; and b) curing a polymerizable composition obtained in process step a) by raising the temperature to at least 50° C., wherein at commencement of process step b) a ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:1 and at least 80% of the isocyanate groups present in the polymerizable composition are aliphatically and/or cycloaliphatically bonded.

12. The process as claimed in claim 11, wherein a period of at least 30 minutes elapses between an end of process step a) and commencement of process step b).

13. The process as claimed in claim 11, wherein a reaction mixture obtained in process step a) is mixed with an organic or inorganic filler before performance of process step b).

14. The process as claimed in claim 13, wherein the organic or inorganic filler consists of fibers having a minimum length of 50 m and the curing in process step b) is carried out in a heated mold which imparts the fiber bundle wetted with the reaction mixture with a profile and stabilizes this profile through curing of the reaction mixture.

15. A polymer obtained by the process as claimed in claim 11 or a composite material obtained by the process as claimed in claim 13.

16. (canceled)

Description

WORKING EXAMPLES

General Information:

[0110] Unless otherwise stated all reported percentage values are in percent by weight (% by weight).

[0111] The ambient temperature of 23° C. at the time of performing the experiments is referred to as RT (room temperature).

[0112] The methods detailed hereinafter for determination of the appropriate parameters were used for performance and evaluation of the examples and are also the methods for determination of the parameters of relevance in accordance with the invention in general.

Determination of Phase Transitions by DSC

[0113] The phase transitions were determined by means of DSC (differential scanning calorimetry) with a Mettler DSC 12E (Mettler Toledo GmbH, Giessen, Germany) in accordance with DIN EN 61006. Calibration was effected via the melt onset temperature of indium and lead. 10 mg of substance were weighed out in standard capsules. The measurement was effected by three heating runs from −50° C. to +200° C. at a heating rate of 20 K/min with subsequent cooling at a cooling rate of 320 K/min. Cooling was effected by means of liquid nitrogen. The purge gas used was nitrogen. The values reported are in each case based on evaluation of the 2nd heating curve. The melting temperatures T.sub.m were obtained from the temperatures at the maxima of the heat flow curves. The glass transition temperature T.sub.g was obtained from the temperature at half the height of a glass transition step.

Determination of Infrared Spectra

[0114] The infrared spectra were measured on a Bruker FT-IR spectrometer equipped with an ATR unit.

Starting Compounds

[0115] Polyisocyanate A1 is an HDI trimer (NCO functionality >3) having an NCO content of 23.0% by weight from Covestro AG. It has a viscosity of about 1200 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

[0116] Polyisocyanate A2 is an HDI trimer (NCO functionality >3) having an NCO content of 23.5% by weight from Covestro AG. It has a viscosity of about 730 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

[0117] Polyisocyanate A3 is a PDI trimer (NCO functionality >3) having an NCO content of 21.5% by weight from Covestro AG. It has a viscosity of about 9500 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

[0118] Polyisocyanate A4 is an HDI/IPDI polyisocyanate having an NCO content of 21.0% by weight from Covestro AG. It has a viscosity of about 22,500 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

[0119] K1: N,N,N′-trimethylaminoethylethanolamine having an OH number of 384 mg KOH/g was obtained from Huntsman Corporation.

[0120] K2: 2-(2-dimethylaminoethoxy)ethanol having an OH number of 421 mg KOH/g was obtained from Huntsman Corporation.

[0121] K3: Benzyldimethylamine was obtained from Huntsman Corporation.

[0122] K4: 2,2′-dimorpholine diethyl ether was obtained from Huntsman Corporation.

[0123] K5: N-(3-dimethylaminopropyl)-N,N-diisopropanolamine having an OH number of 514 mg KOH/g was obtained from Huntsman Corporation.

[0124] K6: Pentamethyldiethylenetriamine was obtained from Covestro AG.

[0125] K7: N,N,N′-trimethyl-N′-hydroxyethylbisaminoethyl ether having an OH number of 295 mg KOH/g was obtained from Huntsman Corporation.

[0126] K8: N,N,N′,N″,N″-pentamethyldipropylenetriamine was obtained from Huntsman Corporation.

[0127] K9: N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine having an OH number of 229 mg KOH/g was obtained from Huntsman Corporation.

[0128] K10: N′-(3-(dimethylamino)propyl)-N,N-dimethyl-1,3-propanediamine was obtained from Huntsman Corporation.

[0129] K11: A mixture of 15% bis[(dimethylamino)methyl]phenol and 2,4,6-tris(dimethylaminomethyl)phenol was obtained from Evonik Industries AG.

[0130] K12: Sodium {N-methyl[(2-hydroxy-5-nonylphenyl)methyl]amino}acetate dissolved in glycol was obtained from Evonik Industries AG.

[0131] K13: Tris(dimethylaminopropyl)hydrotriazine was obtained from Evonik Industries AG.

[0132] Polyethylene glycol (PEG) 400 was obtained with a purity of >99% by weight from ACROS.

[0133] The mold release agent INT-1940® was obtained from Axel Plastics Research Laboratories, INC. and according to the data sheet is a mixture of organic fatty acids and esters.

[0134] All raw materials except for the catalysts were degassed under reduced pressure prior to use and the polyethylene glycol was additionally dried.

Production of the Reaction Mixture

[0135] Unless otherwise stated the reaction mixture was produced by mixing polyisocyanate (A1-A4) with a corresponding amount of catalyst (K1-K14) and additive at 23° C. in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.−1. Said mixture was then poured into a suitable mold for crosslinking and cured without further treatment or used for pultrusion without further treatment.

Performance of the Pultrusion Experiments

[0136] The pultrusion experiments were carried out using a Pultrex Px 500-10 system from Pultrex. The fiber bundles were in rolls on a rack and were first pulled through a fiber presort/orientation (perforated plate), then impregnated with resin at room temperature by means of an open dipping bath with deflectors and strippers or in an injection box and then pulled into the heated mold (profile block). The mold had a length of 1000 mm over which were distributed 4 successively connected heating zones of equal size (H1 to H4, H1 at the glass fiber intake). This was followed by an air-cooled cooling zone of 5 m, to which the two pullers were connected. These worked with an appropriate offset, such that there was a continuous tensile force on the profile which transported the profile in the direction of the saw which followed after the pullers and cut the profile to the desired length. The profile cross section was a rectangle having dimensions of 120 mm×3 mm. When using an immersion bath to wet the fibers the stripped excess resin was returned to the bath and reused.

Working Example 1

[0137] A resin mixture composed of polyisocyanate A1 (4.86 kg), catalyst K1 (0.01 kg), zinc stearate (0.03 kg) and INT-1940® (0.10 kg) was produced as described hereinabove. The glass fiber bundles (128 rovings) were oriented and guided into the injection box which was fixedly connected to the mold and filled with the resin mixture via a window opening on the top of the box. The glass fibers thus impregnated with resin were pulled directly into the heated mold. The temperature zones were H1=180° C., H2=220° C., H3=200° C. and H4=180° C. The pulling rate was 0.3 m/min. The takeoff forces were 0.3 t. 8 m of profile were produced. Further measured results are summarized in table 2.

Working Examples 2-13

[0138] The amounts of polyisocyanate reported in table 1, catalyst and optionally additive were treated in accordance with the abovementioned production procedure for reaction mixtures. Curing in the oven was performed according to the times and temperatures likewise reported in.

[0139] The T.sub.g of the cured reaction mixtures was 78-154° C. The viscosities of the inventive reaction mixtures with polyisocyanate A1 (examples 2, 3 and 4) were 1.58-1.61 Pa.Math.s immediately after production and rose to 1.65-1.77 Pa.Math.s over 4 h. The viscosity with polyisocyanate A3 (example 12) was 10.4 Pa.Math.s immediately after production and rose to 10.6 Pa.Math.s over 4 h. The viscosity with polyisocyanate A4 (example 13) was 23.0 Pa.Math.s immediately after production and rose to 24.1 Pa.Math.s over 4 h.

[0140] Working examples 2 and 3 show that different catalysts according to formula (I) may be utilized for curing of isocyanates. The inventive examples 4 to 7 show that different amounts of catalyst can result in polymerization even at relatively low curing temperatures. Embodiments 9 to 11 show that no additives are necessary, but different additives are tolerated. Effective catalysis was also demonstrated for further isocyanates by means of inventive examples 12 and 13.

Comparative Examples 14-24

[0141] The amounts of polyisocyanate reported in table 1, catalyst and optionally additive were treated in accordance with the abovementioned production procedure for reaction mixtures. Curing in the oven was performed according to the times and temperatures likewise reported in Error! Reference source not found.

[0142] The comparative examples show that various other amine-based catalysts do not result in solid materials under the same curing conditions as the inventive examples.

Working Examples 25-33 for Identifying Further Suitable Compounds for Producing Adducts

[0143] The catalytic activity of the compounds was determined with an n-hexyl isocyanate as the model substrate. The most quantitatively significant reaction product was a trimer. The reaction of the NCO groups was verified by .sup.13C-NMR at 100 MHz. The solvent used for the samples was deuterochloroform, its non-deuterated fraction serving as internal standard.

[0144] Compounds K14 to K16 were tested.

[0145] K14: 3-(dimethylamino)-propanol

[0146] K15: 4-(dimethylamino)-butanol

[0147] K16: 5-(dimethylamino)-pentanol

[0148] n-Hexyl isocyanate was in each case admixed with the concentrations of compounds K14, K15 or K6 reported in table 2 which follows. Incubation was carried out under the specified conditions.

TABLE-US-00001 TABLE 2 Experiment Compound Reaction parameters Result 29 3-(dimethylamino)-propanol 80° C. for 2 h, 20 mol % Trimerization detectable but residual NCO content 30 3-(dimethylamino)-propanol 150° C. for 5 min, 20 mol % Trimerization detectable but residual NCO content 31 3-(dimethylamino)-propanol 150° C. for 5 min, 0.5 mol % No reaction detectable 32 4-(dimethylamino)-butanol 80° C. for 2 h, 20 mol % Complete reaction of NCO groups 33 4-(dimethylamino)-butanol 150° C. for 5 min, 20 mol % Complete reaction of NCO groups 34 4-(dimethylamino)-butanol 150° C. for 5 min, 0.5 mol % Complete reaction of NCO groups 35 5-(dimethylamino)-pentanol 80° C., 2 h, 20 mol % No reaction detectable 36 5-(dimethylamino)-pentanol 150° C., 5 min, 20 mol % Complete reaction of NCO groups 37 5-(dimethylamino)-pentanol 150° C., 5 min, 0.5 mol % No reaction detectable

[0149] The experiment shows that alkylene radicals without heteroatoms are also suitable as radical R.sup.5 to the extent that they contain 3 to 5 carbon atoms. Radicals R.sup.5 made of 4 carbon atoms are optimal. Corresponding compounds are of course also suitable starting materials for the production of the inventive adducts.

TABLE-US-00002 TABLE 1 Compositions, production conditions and material properties of working and comparative examples. Amount of Curing T.sub.g polyisocyanate Amount Amount temperature Curing time Pot life after Appearance Ex. Isocyanate [g] Cat. [g] Additives [g] [° C.] [min] at RT curing after curing 2 (inv.) A1 97 K1 0.5 zinc stearate 0.5 220 5 >4 h 103° C. solid 3 (inv.) A1 97 K2 0.5 zinc stearate 0.5 220 5 >4 h  91° C. solid 4 (inv.) A1 97.25 K1 0.25 zinc stearate 0.5 120 30 >4 h 107° C. solid 5 (inv.) A1 97 K1 0.5 zinc stearate 0.5 120 30 n.d. 101° C. solid 6 (inv.) A1 96.5 K1 1 zinc stearate 0.5 120 30 n.d. 104° C. solid 7 (inv.) A1 95.5 K1 2 zinc stearate 0.5 120 30 n.d. 102° C. solid 8 (inv.) A2 93.5 K1 0.25 zinc stearate/ 0.5/0.75 220 5 n.d. 154° C. solid PEG 400 9 (inv.) A1 99.75 K1 0.25 220 22 n.d. 113° C. solid 10 (inv.) A1 99.75 K1 0.25 PEG 400 2 220 5 n.d. 108° C. solid 11 (inv.) A1 99.75 K1 0.25 PEG 400 4 220 5 n.d.  92° C. solid 12 (inv.) A3 97.25 K1 0.25 zinc stearate 0.5 220 5 >4 h 135° C. solid 13 (inv.) A4 97.25 K1 0.25 zinc stearate 0.5 220 5 >4 h  78° C. solid 14 (comp.) A1 97 K3 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 15 (comp.) A1 97 K4 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 16 (comp.) A1 97 K5 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 17 (comp.) A1 97 K6 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 18 (comp.) A1 97 K7 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 19 (comp.) A1 97 K8 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 20 (comp.) A1 97 K9 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 21 (comp.) A1 97 K10 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 22 (comp.) A1 97 K11 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 23 (comp.) A1 97 K12 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid 24 (comp.) A1 97 K13 0.5 zinc stearate 0.5 220 5 n.d. does not cure liquid n.d.: not determined

TABLE-US-00003 TABLE 2 Mechanical characteristics of inventive composite example 1. Example 1 Test (inv.) Tensile test DIN EN ISO 527 Tensile modulus GPa 54.7 Yield stress MPa 876 Elongation at break % 1.65 Flexural test DIN EN ISO 14125 Flexural modulus (axial) GPa 47.1 Flexural stress (axial) MPa 650 Flexural strain (axial) % 2.87 Flexural modulus (transv.) GPa 10.9 Flexural stress (transv.) MPa 54 Flexural strain (transv.) % 0.57 Charpy DIN EN ISO 179 Ak kJ/m.sup.2 353 Filler content DIN EN ISO 1172/A wt % 81.6 Density DIN EN ISO 1183-1 g/cm.sup.3 2.142 Coefficient of expansion according to DIN 53572 axial 10.sup.−6/K 5.70 transv. 10.sup.−6/K 3.30 DMA (3-point flexural test) DIN EN ISO 6721-1 Tangent δ ° C. 106 ILSS DIN EN ISO 14130 axial MPa 28.5 transv. MPa 4.78