ADDUCTS OF AMINE CATALYSTS FOR PRODUCING ISOCYANURATE POLYMERS

Abstract

The present invention relates to urethane, thiourethane and urea adducts of tertiary amines and the use thereof as catalysts for the crosslinking of aliphatically, cycloaliphatically, araliphatically or aromatically bonded isocyanate groups with one another. The catalysts according to the invention have the particular advantage that they are thermolatent.

Claims

1. An adduct of a compound having at least one isocyanate group and a compound according to formula (I): ##STR00011## 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); ##STR00012## 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 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 the adduct no longer comprises any free isocyanate-reactive groups.

2. The adduct according to claim 1, wherein R.sup.5 is the radical of formula (II) and A is NR.sup.3−, where R.sup.3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, and isobutyl.

3. The adduct according to claim 1, wherein R.sup.5 is the radical of formula (II) and A is oxygen.

4. The adduct according to claim 1, wherein R.sup.5 is butylene.

5. The adduct according to claim 1, wherein the isocyanate is a monomeric or oligomeric isocyanate having aliphatically or cycloaliphatically bonded isocyanate groups.

6. The adduct according to claim 1, comprising a first compound having at least one aliphatically bound isocyanate group and a second compound having at least one aromatically bound isocyanate group, wherein the first compound makes up at least 50 wt.-% of all isocyanates used for preparing the adduct and the second compound makes up 5 wt.-% to 50 wt.-% of all isocyanates used for preparing the adduct.

7. A method of crosslinking at least two isocyanate groups, comprising catalyzing crosslinking of at least two isocyanate groups using the adduct of claim 1, wherein the at least two isocyanate groups comprise one or more of aliphatically, cycloaliphatically, araliphatically, or aromatically bonded isocyanate groups.

8. The method according to claim 7, wherein the catalyzing results in a highly crosslinked polymer.

9. A polymerizable composition comprising a) at least one polyisocyanate having isocyanate groups comprising one or more of aliphatically, cycloaliphatically, araliphatically, or aromatically bonded isocyanate groups; and b) at least one adduct according to claim 1; wherein a molar ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:1.

10. The polymerizable composition according to claim 9, wherein the polyisocyanate component of the polymerizable composition comprises at least 80% by weight of at least one polyisocyanate selected from the group consisting of monomeric HDI, oligomeric HDI, monomeric PDI, oligomeric PDI, monomeric H12MDI, oligomeric H12MDI, monomeric IPDI, and oligomeric IPDI.

11. A kit comprising a) at least one polyisocyanate having isocyanate groups comprising one or more of aliphatically, cycloaliphatically, araliphatically, or aromatically bonded isocyanate groups; and b) at least one adduct according to claim 1.

12. (canceled)

13. A process for producing a polymer comprising a) mixing at least one polyisocyanate having isocyanate groups comprising one or more of aliphatically, cycloaliphatically, araliphatically, or aromatically bonded isocyanate groups with an adduct according to claim 1 to form a polymerizable composition; and b) curing the polymerizable composition 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.

14. The process according to claim 13, wherein a period of at least 30 minutes elapses between the end of process step a) and commencement of process step b).

15. The process according to claim 13, wherein the polymerizable composition is mixed with an organic or inorganic filler before performance of process step b).

16. The process according to claim 15, wherein the organic or inorganic filler comprises fibres having a minimum length of 50 m and the curing in process step b) is carried out in a heated mould which imparts the fibre bundle wetted with the polymerizable composition with a profile and stabilizes the profile by the curing of the polymerizable composition.

17. A polymer obtained by the process according to claim 13.

18. A composite material obtained by the process according to claim 15.

Description

FIGURES

[0167] FIG. 1 shows the viscosities of the adducts of example 42 at different temperatures

[0168] The working examples which follow serve merely to illustrate the invention. They are not intended to limit the scope of protection of the patent claims in any manner.

WORKING EXAMPLES

General Details:

[0169] All percentages, unless stated otherwise, are based on percent by weight (% by weight).

[0170] The ambient temperature of 23° C. at the time of conducting the experiments is referred to as RT (room temperature).

[0171] The methods detailed hereinafter for determining the relevant parameters were employed for performing/evaluating the examples and are also the methods for determining the parameters relevant in accordance with the invention in general.

Determination of Phase Transitions by DSC

[0172] 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 curve. 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

[0173] The infrared spectra were measured on a Bruker FT-IR spectrometer equipped with an ATR unit.

Dynamic Mechanic Analysis (DMA

[0174] The temperature at which crosslinking started was determined by DMA. Glass fiber tissue was wetted with the reaction mixture and tested with an amplitude of 200μ, a heating rate of 2 k per minute and an excitation frequency of 2 Hz. The temperatures given in table 5 indicate the onset of crosslinking.

Starting Compounds

[0175] Polyisocyanate A1 is an HDI trimer (NCO functionality >3) having an NCO content of 23.0% by weight from Covestro AG. The viscosity is about 1200 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

[0176] Polyisocyanate A2 is HDI having an NCO content of 49.7% by weight from Covestro AG.

[0177] Polyisocyanate A3 is IPDI having an NCO content of 37.5% by weight from Covestro AG.

[0178] Polyisocyanate A4 is H12MDI having an NCO content of 31.8% by weight from Covestro AG.

[0179] Monoisocyanate A5 is cyclohexyl isocyanate and was obtained in a purity of >98% from Sigma-Aldrich.

[0180] Monoisocyanate A6 is phenyl isocyanate and was obtained in a purity of 98% from Sigma-Aldrich.

[0181] Monoisocyanate A7 is octadecyl isocyanate and was obtained in a purity of 98% from Sigma-Aldrich.

[0182] Monoisocyanate A8 is hexyl isocyanate and was obtained in a purity of 97% from Sigma-Aldrich.

[0183] Polyisocyanate A9 is 1,3-bis(isocyanatomethyl)benzene having an NCO content of 44% by weight from Covestro AG.

[0184] Polyisocyanate A10 is 2,4′-diphenylmethane diisocyanate having an NCO content of 33.6% by weight from Covestro AG.

[0185] Polyisocyanate A11 is a mixture of 2,4- and 2,6-tolylene diisocyanate in a ratio of 80:20 having an NCO content of 48% by weight from Covestro AG.

[0186] Polyisocyanate A12 is 4,4′-diphenylmethane diisocyanate having an NCO content of 33.6% by weight from Covestro AG.

[0187] Polyisocyanate A13 is a polyisocyanate based on diphenylmethane diisocyanate having an NCO content of 31.5% by weight from Covestro AG. The viscosity is about 90 mPa.Math.s at 25° C. (DIN EN ISO 3219/A.3).

[0188] K1: N,N,N′-trimethylaminoethylethanolamine having an OH number of 384 mg KOH/g was obtained from Huntsman Corporation.

[0189] K2: 2-(2-dimethylaminoethoxy)ethanol having an OH number of 421 mg KOH/g was obtained from Huntsman Corporation.

[0190] K3: Benzyldimethylamine was obtained from Huntsman Corporation.

[0191] K4: 2,2′-dimorpholine diethyl ether was obtained from Huntsman Corporation.

[0192] K5: N-(3-dimethylaminopropyl)-N,N-diisopropanolamine having an OH number of 514 mg KOH/g was obtained from Huntsman Corporation.

[0193] K6: Pentamethyldiethylenetriamine was obtained from Covestro AG.

[0194] K7: N,N,N′-trimethyl-N′-hydroxyethylbisaminoethyl ether having an OH number of 295 mg KOH/g was obtained from Huntsman Corporation.

[0195] K8: N,N,N′,N″,N″-pentamethyldipropylenetriamine was obtained from Huntsman Corporation.

[0196] K9: N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine having an OH number of 229 mg KOH/g was obtained from Huntsman Corporation.

[0197] K10: N′-(3-(dimethylamino)propyl)-N,N-dimethyl-1,3-propanediamine was obtained from Huntsman Corporation.

[0198] K11: A mixture of 15% bis[(dimethylamino)methyl]phenol and 2,4,6-tris(dimethylaminomethyl)phenol was obtained from Evonik Industries AG.

[0199] K12: Sodium {N-methyl[(2-hydroxy-5-nonylphenyl)methyl]amino}acetate dissolved in glycol was obtained from Evonik Industries AG.

[0200] K13: Tris(dimethylaminopropyl)hydrotriazine was obtained from Evonik Industries AG.

[0201] All raw materials except for the catalyst were degassed under vacuum before use.

Production of the Catalyst Adducts

[0202] The isocyanate was added dropwise to the catalyst K1/K2 with cooling and the mixture was then stirred until homogeneous and until residual isocyanate was no longer detectable by IR analysis.

TABLE-US-00001 TABLE 1 Usage amounts of isocyanates and catalysts for producing catalyst adducts KA1 to KA14. Catalyst Amount of Amount of adduct Isocyanate isocyanate [g] Catalyst catalyst [g] KA1 A1 18.3 K1 14.6 KA2 A1/A2 9.15/4.2 K1 14.6 KA3 A2 8.4 K1 14.6 KA4 A2 8.4 K1 13.14 KA5 A1 18.3 K1 13.14 KA6 A1/A2 9.15/4.2 K1 13.14 KA7 A3 44.4 K1 58.4 KA8 A4 52.4 K1 58.4 KA9 A5 2.50 K1 2.92 KA10 A6 2.38 K1 2.92 KA11 A7 5.91 K1 2.92 KA12 A8 2.54 K1 2.92 KA13 A1 366 K2 266 KA14 A9 29.2 K1 16.13

Production of Catalyst Adducts Using Solvent

[0203] The isocyanate in ethyl acetate was added dropwise to the catalyst K1 in ethyl acetate with cooling and the mixture was then stirred until homogeneous and until residual isocyanate was no longer detectable by IR analysis. The solvent was then removed under reduced pressure.

TABLE-US-00002 TABLE 2 Usage amounts of isocyanates and catalysts for producing catalyst adducts KA15 to KA17. Amount of Amount of isocyanate in catalyst K1 in amount of ethyl amount of ethyl Catalyst adduct Isocyanate acetate [g] acetate [g] KA15 A10 12.5 in 37.5 14.6 in 14.6 KA16 A11 17.5 in 17.5 29.2 in 29.2 KA17 A12 12.5 in 37.5 14.6 in 14.6

Production of the Reaction Mixture

[0204] Unless otherwise stated the reaction mixture was produced by mixing polyisocyanate (A1) with a corresponding amount of catalyst and additive at 23° C. in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.−1. Without any further treatment said mixture was then poured into a suitable mould for crosslinking and cured.

Working Examples 1-17

[0205] The amounts of polyisocyanate A1 reported in table 1, catalyst adduct and in each case 0.5 g of zinc stearate were treated in accordance with the abovementioned production procedure for reaction mixtures. Curing in an oven was performed at 220° C. over 5 min. The T.sub.g of the cured reaction mixtures was 81-113° C. The viscosities of the inventive reaction mixtures comprising polyisocyanate A1 (examples 1 and 3) were 1.27-1.30 Pa-s directly after production and in both cases increased to 1.36 Pa-s over 4 h.

[0206] The working examples 1 to 17 show that these catalysts may be reacted with various isocyanates to form adducts which, in turn, are all catalytically active.

Comparative Examples 18-28

[0207] The amounts of polyisocyanate A1 reported in table 2, catalyst and in each case 0.5 g of zinc stearate were treated in accordance with the abovementioned production procedure for reaction mixtures. Curing in an oven was performed at 220° C. over 5 min. The comparative examples show that various other amine-based catalysts do not result in solid materials under the same curing conditions.

TABLE-US-00003 TABLE 3 Compositions and material properties of working and comparative examples. Amount of Amount polyisocyanate of cat. Pot life T.sub.g after Appearance Ex. A1 [g] Cat. [g] at RT curing after curing  1 (inv.) 97 KA1 1.13 >4 h 109° C. solid  2 (inv.) 97 KA2 0.96 n.d. 109° C. solid  3 (inv.) 97 KA3 0.79 >4 h 108° C. solid  4 (inv.) 97 KA4 0.82 n.d. 113° C. solid  5 (inv.) 97 KA5 1.2 n.d. 101° C. solid  6 (inv.) 97 KA6 1.01 n.d. 105° C. solid  7 (inv.) 96.93 KA7 1.01 n.d.  92° C. solid  8 (inv.) 96.93 KA8 1.08 n.d.  92° C. solid  9 (inv.) 96.93 KA9 1.72 n.d. 101° C. solid 10 (inv.) 96.93 KA10 1.06 n.d. 100° C. solid 11 (inv.) 96.93 KA11 1.03 n.d.  92° C. solid 12 (inv.) 96.93 KA12 1.07 n.d. 103° C. solid 13 (inv.) 96.93 KA13 1.20 n.d.  81° C. solid 14 (inv.) 96.93 KA14 1.61 n.d.  98° C. solid 15 (inv.) 96.93 KA15 1.06 n.d.  92° C. solid 16 (inv.) 96.93 KA16 1.53 n.d.  98° C. solid 17 (inv.) 96.93 KA17 1.06 n.d.  83° C. solid 18 (comp.) 97 K3 0.5 n.d. does not cure liquid 19 (comp.) 97 K4 0.5 n.d. does not cure liquid 20 (comp.) 97 K5 0.5 n.d. does not cure liquid 21 (comp.) 97 K6 0.5 n.d. does not cure liquid 22 (comp.) 97 K7 0.5 n.d. does not cure liquid 23 (comp.) 97 K8 0.5 n.d. does not cure liquid 24 (comp.) 97 K9 0.5 n.d. does not cure liquid 25 (comp.) 97 K10 0.5 n.d. does not cure liquid 26 (comp.) 97 K11 0.5 n.d. does not cure liquid 27 (comp.) 97 K12 0.5 n.d. does not cure liquid 28 (comp.) 97 K13 0.5 n.d. does not cure liquid

Working Examples 29-37 for Identifying Further Suitable Compounds for Producing Adducts

[0208] 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.

[0209] Compounds K14 to K16 were tested.

[0210] K14: 3-(dimethylamino)-propanol

[0211] K15: 4-(dimethylamino)-butanol

[0212] K16: 5-(dimethylamino)-pentanol

[0213] n-Hexylisocyanate was in each case admixed with the concentrations of the compounds K14, K15 and K6 reported in the table which follows. Incubation was carried out under the specified conditions

TABLE-US-00004 TABLE 4 Reaction Experiment Compound parameters Result 29 3-(dimethylamino)- 80° C. for Trimerization propanol 2 h, 20 mol % detectable but residual NCO content 30 3-(dimethylamino)- 150° C. for Trimerization propanol 5 min, 20 mol % detectable but residual NCO content 31 3-(dimethylamino)- 150° C. for No reaction propanol 5 min, 0.5 mol % detectable 32 4-(dimethylamino)- 80° C. for Complete reaction butanol 2 h, 20 mol % of NCO groups 33 4-(dimethylamino)- 150° C. for Complete reaction butanol 5 min, 20 mol % of NCO groups 34 4-(dimethylamino)- 150° C. for Complete reaction butanol 5 min, 0.5 mol % of NCO groups 35 5-(dimethylamino)- 80° C., No reaction pentanol 2 h, 20 mol % detectable 36 5-(dimethylamino)- 150° C., Complete reaction pentanol 5 min, 20 mol % of NCO groups 37 5-(dimethylamino)- 150° C., No reaction pentanol 5 min, 0.5 mol % detectable

[0214] 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.

[0215] Corresponding compounds are of course also suitable starting materials for the production of the inventive adducts.

Inventive Examples 38 to 41 for Investigating the Effect of Isocyanate on Activity of Catalyst

[0216] It was to be investigated whether the structure of the polyisocyanate used for producing the adduct (aliphatic or aromatic) has an effect on the catalytic activity of the adduct.

[0217] The INT-1940® demoulding agent was obtained from Axel Plastics Research Laboratories, INC. and according to the datasheet is a mixture of organic fatty acids and esters.

Production of the Reaction Mixture

[0218] Unless otherwise stated the reaction mixture was produced by mixing the polyisocyanate with a corresponding amount of catalyst and additive at 23° C. in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.−1. Without any further treatment said mixture was then poured into a suitable mould for crosslinking and cured. Part of the mixture was subsequently used to carry out investigations on pot life.

Working Example 38

[0219] A resin mixture composed of isocyanate A1 (2.47 g), polyisocyanate A13 (22.23 g) and catalyst KA1 (0.30 g) was produced. Curing in the oven for 5 min at 220° C. afforded a solid material having a T.sub.g of over 200° C. The gel time of the resin mixture at room temperature was more than 22 hours. After 24 h of storage at room temperature a liquid material having a gelled top was obtained.

Working Example 39

[0220] A resin mixture composed of isocyanate A1 (5.00 g), polyisocyanate A13 (19.38 g) and catalyst KA1 (0.63 g) was produced. Curing in the oven for 60 min at 100° C. afforded a solid material having a T.sub.g of more than 280° C. Thermal curing reduced the height of the characteristic NCO band between 2300 to 2250 cm.sup.−1 by at least 80%. The gel time of the resin mixture at room temperature was more than 22 h. After 24 h of storage at room temperature a liquid material having a gelled top was obtained.

Working Example 40

[0221] A resin mixture composed of isocyanate A1 (3.50 g), polyisocyanate A13 (16.20 g) and catalyst KA1 (0.4 g) was produced. Curing in the oven for 10 min at 100° C. afforded a solid material having a T.sub.g of more than 280° C. Thermal curing reduced the height of the characteristic NCO band between 2300 to 2250 cm.sup.−1 by at least 80%. The gel time of the resin mixture at room temperature was more than 22 h. After 24 h of storage at room temperature a liquid material having a gelled top was obtained.

Working Example 41

[0222] A resin mixture composed of isocyanate A1 (96.30 g), INT-1940® (2.50 g) and catalyst KA16 (1.2 g) was produced. The material became hot and then solid over one minute, thus forming a material having a T.sub.g of 101° C. Exothermic curing reduced the height of the characteristic NCO band between 2300 to 2250 cm.sup.−1 by at least 80%.

[0223] Examples 38 to 40 show that adducts produced with aliphatic polyisocyanates are very good thermolatent catalysts. Reaction mixtures containing said catalysts are storable for more than 20 hours at room temperature without viscosity increase impairing the processability of the mixture. This was surprisingly also found for reaction mixtures having high proportions of aromatic polyisocyanates which are very reactive in combination with conventional catalysts. Nevertheless, a rapid curing of the reaction mixture is possible at elevated temperature. Thus example 38 required only 5 minutes at 220° C. for curing.

[0224] By contrast, if an aromatic polyisocyanate is used for producing the adduct even normally rather slowly reacting aliphatic polyisocyanates (example 41) undergo a very rapid reaction.

[0225] The catalytic properties of the inventive adducts can accordingly be controlled through the choice of a suitable polyisocyanate. Reaction systems which react spontaneously and very rapidly at room temperature as well as systems having a very pronounced thermolatency are obtainable.

Working Example 42: Properties of Adducts Based on Mixtures of Aromatic and Aliphatic Isocyanates

[0226] The adducts were prepared as described above. They were derived from K1. Mixtures of HDI and MDI in different proportions were used instead of pure isocyanates. Viscosity at different temperatures and pot life at 23° C. were determined. Onset of crosslinking was determined by DMA. The results are summarized in table 5 below. Pot life was determined at 23° C. It is defined as the time in which viscosity of the reaction mixture doubled.

[0227] The reaction mixture consisted of polyisocyanate A1 and the respective adduct. The concentration of the adduct was adjusted so that the concentration of the amine as core was always 0.5 wt.-%. The concentration of the adduct thus differed as MDI and HDI have different molecular weights and are present in different proportions.

TABLE-US-00005 TABLE 5 Viscosity at Viscosity at Onset of 20° C. 60° C. Pot crosslinking [mPa*s] [mPa*s] life [° C.] MDI 4,750,000 15,000* >4 h 98.2 MDI-HDI 257,000 2,350 134 min. 94.3 (80:20) MDI-HDI 46,800 1,650 62 min. 90.4 (50:50) MDI-HDI solid   227 >6 h 107.6 (20:80) MDI-HDI solid   219 >6 h 136.8 (5:95) HDI solid 2,460 >4 h 120.0 *inaccurate measurement as adduct had a high viscosity which prevented easy mixing

[0228] It can be seen from table 5 as well as FIG. 1 that at 60° C. adducts which comprise between 5 wt.-% and 50 wt.-% MDI have a lower viscosity than adducts prepared with pure HDI or pure MDI. These adducts retain a pot life of at least one hour while having a low crosslinking temperature which is still practically useful.