COMPOSITE MATERIALS BASED ON DUAL-CURING ISOCYANURATE POLYMERS

Abstract

The present invention relates to polymerizable compositions which contain components that can be crosslinked both via isocyanurate bonds and by a radical reaction mechanism. The invention further relates to methods by way of which polymers can be produced from said compositions.

Claims

1.-15. (canceled)

16. A polymerizable composition for production of a composite material, comprising a) a reactive resin having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0:1.0, comprising the following components: a1) an isocyanate component A; a2) at least one trimerization catalyst C; and a3) at least one component selected from the group consisting of components B, D and E, where component B has at least one ethylenic double bond but no isocyanate-reactive group; component D has at least one isocyanate-reactive group and at least one ethylenic double bond in one molecule; and component E has both at least one isocyanate group and at least one ethylenic double bond in one molecule; and b) at least one filler J.

17. The polymerizable composition as claimed in claim 16, wherein the reactive resin a) contains at least one component B.

18. The polymerizable composition as claimed in claim 16, wherein the reactive resin a) contains at least one component D or E.

19. The polymerizable composition as claimed in claim 17, wherein the quantitative ratio of component A to the total amount of components B, D and E is such that the reactive resin has a viscosity of not more than 10000 mPas.

20. The polymerizable composition as claimed in claim 16, wherein the molar ratio of isocyanate groups to isocyanate-reactive groups in the reactive resin is at least 4.0:1.0.

21. The polymerizable composition as claimed in claim 16, wherein the reactive resin additionally contains a component F suitable as an initiator for a free-radical polymerization of the ethylenic double bonds present in the polymerizable composition of the invention.

22. The use of at least one component selected from the group consisting of components B, D and E for production of a polymerizable composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0:1.0, which contains an isocyanate component A and a filler J and is polymerizable either by free-radical polymerization or by crosslinking of isocyanate groups with one another.

23. A process for preparing a polymer, comprising the steps of a) providing a reactive resin as defined in claim 16; b) providing at least one filler J; c) wetting the filler J with the reactive resin mixture; d) crosslinking the ethylenic double bonds present in said polymerizable composition; and e) crosslinking the isocyanate groups present in said polymerizable composition; wherein process steps d) and e) are conducted simultaneously or in any desired sequence and process step c) is conducted prior to process steps d) and e).

24. The process as claimed in claim 23, wherein the reactive resin comprises a heat-activated initiator F2, the polymerizable composition comprises at least one fibrous filler J3 and process steps d) and e) are conducted in parallel.

25. The process as claimed in claim 23, wherein the polymerizable composition comprises at least one component E and the process comprises a further process step d) in which the isocyanate-reactive group of component E is crosslinked with an isocyanate group of the isocyanate component A or of a reaction product of the isocyanate component A.

26. The process as claimed in claim 23, wherein, in process step b), at least 50% of the free isocyanate groups present in isocyanate component A are converted to isocyanurate structural units.

27. A composite material obtainable by the process as claimed in claim 23.

28. The composite material as claimed in claim 27, in the form of a profile.

29. The composite material as claimed in claim 27, in the form of a hollow body.

30. The composite material as claimed in claim 27, in the form of a shaped body and produced by a casting method.

Description

EXAMPLES

General Details

[0160] All percentages, unless stated otherwise, are based on percent by weight (% by weight).

[0161] The ambient temperature of 23 C. at the time of conduct of the experiments is referred to as RT (room temperature).

[0162] The methods detailed hereinafter for determination of the appropriate parameters were employed for conduction 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

[0163] 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 each based on the evaluation of the 2nd heating 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

[0164] The infrared spectra were measured on a Bruker FT-IR spectrometer equipped with an ATR unit.

Starting Compounds

[0165] Polyisocyanate A1: HDI trimer (NCO functionality>3) with 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).

[0166] Polyisocyanate A2: PDI trimer (NCO functionality>3) with an NCO content of 21.5% by weight from Covestro AG. The viscosity is about 9500 mPa.Math.s at 23 C. (DIN EN ISO 3219/A.3).

[0167] Hexanediol diacrylate (HDDA) was sourced with a purity of <=100% by weight from Sigma-Aldrich,

[0168] Hydroxypropyl methacrylate (HPMA) was sourced with a purity of 98% by weight from abcr GmbH,

[0169] Isobornyl methacrylate (IBOMA) was sourced with a purity of <=100% by weight from Sigma-Aldrich.

[0170] Initiator: Trigonox C. (tert-butyl peroxybenzoate) was sourced with a purity of 98% by weight from Akzo Nobel.

[0171] Potassium acetate was sourced with a purity of >99% by weight from ACROS. Polyethylene glycol (PEG) 400 was sourced with a purity of >99% by weight from ACROS.

[0172] The INT-1940 RTM demolding agent was acquired from Axel Plastics Research Laboratories, INC. and, according to the datasheet, is a mixture of organic fatty acids and esters.

[0173] The short glass fibers designated 910A-10P were supplied by Owens Corning and were in the form of bundles of about 4.5 mm in length. The diameter of the individual fibers was 0.01 mm.

[0174] The endless glass fiber was glass fiber bundles with standard size for UP, VE and epoxy resins with the product name Advantex 399 with 4800 tex from 3B-fiberglass. According to the datasheet, the endless glass fibers have a diameter of 24 micrometers, are boron-free and consist of E-CR glass. The tensile modulus is 81-83 GPa, the tensile strength 2200-2400 MPa and the density 2.62 g/cm.sup.3.

[0175] All raw materials except for the catalyst were degassed under reduced pressure prior to use, and the polyethylene glycol was additionally dried.

Preparation of Catalyst K

[0176] Potassium acetate (5.0 g) was stirred in the PEG 400 (95.0 g) at RT until all of it had dissolved. In this way, a 5% by weight solution of potassium acetate in PEG 400 was obtained and was used as catalyst without further treatment.

Preparation of the Reaction Mixtures

[0177] Unless stated otherwise, the polyisocyanurate composites were produced by first preparing the isocyanate composition by mixing the appropriate isocyanate components (A1 or A2) with an appropriate amount of catalyst K, initiator and acrylate at 23 C. in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.1 for 60-300 seconds. Subsequently, one tenth of the amount of short glass fibres was added at first to the isocyanate composition. The overall mixture was mixed in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.1 for 60 to 300 seconds, in the course of which the short glass fiber bundles are exfoliated and the whole mixture forms a slurry-like mass. Then the remaining amount of short glass fibers is added and the mixture is mixed again in the Speedmixer at 2750 min.sup.1 for about 60 seconds.

[0178] Subsequently, the mixture was transferred to a mold (metal lid, about 6 cm in diameter and about 1 cm in height) and cured in an oven.

Working Example 1

[0179] As described above, polyisocyanate A1 (16.13 g) was treated with initiator I (0.064 g), catalyst K (0.595 g) and HPMA (1.60 g) according to the abovementioned preparation method for reaction mixtures, and the mass was introduced into the mold without addition of glass fibers. After the preparation, the mixture had a viscosity of 929 mPas.

[0180] After curing at 200 C. for 3 min, a material with a T.sub.G of 58 C. was obtained.

[0181] After stepwise curing at 100 C. for 3 min and at 200 C. for 3 min, a material with a T.sub.G of 87 C. was obtained.

Working Example 2

[0182] As described above, polyisocyanate A1 (16.13 g) was treated with initiator I (0.064 g), catalyst K (0.595 g) and HPMA (1.60 g) according to the abovementioned preparation method for reaction mixtures, the short glass fibers (4.0 g) were incorporated and the mass was introduced into the mold.

[0183] After curing at 200 C. for 3 min, a material with a T.sub.G of 87 C. was obtained.

[0184] After curing at 100 C. for 2 min and at 200 C. for 2 min, a material with a T.sub.G of 91 C. was obtained.

Working Example 3

[0185] As described above, polyisocyanate A1 (32.2 g) was treated with initiator I (0.12 g), catalyst K (12.3 g), HPMA (0.29 g), HDDA (3.08 g), IBOMA (3.08 g) according to the abovementioned preparation method for reaction mixtures. After the preparation, the material had a viscosity of 611 mPas. After curing at 220 C. for 5 min, a material with a T.sub.G of 102 C. was obtained.

Working Example 4

[0186] As described above, polyisocyanate A2 (29.7 g) was treated with initiator I (0.16 g), catalyst K (1.23 g), HPMA (0.41 g), HDDA (4.21 g), IBOMA (4.21 g) according to the abovementioned preparation method for reaction mixtures. After the preparation, the mixture had a viscosity of 1560 mPas. After curing at 200 C. for 10 min, a material with a T.sub.G of 126 C. was obtained.

[0187] Production of the Resin Mixture for Pultrusion

[0188] The isocyanate was initially charged in an open vessel at room temperature and stirred by means of a Dispermat and dissolver disk at 100 revolutions per minute (rpm). Subsequently, first the acrylate and then the demolding agent were added, and the stirrer speed was increased to 300 rpm and the whole mixture was stirred for a further 5 min, so as to form a homogeneous mixture. Then the catalyst solution and the initiator were metered in and the resin mixture was stirred at 300 rpm for a further 5 min. This reactive resin mixture was used without further treatment for the pultrusion.

Working Example 5

[0189] As described above, polyisocyanate A1 (3.22 kg) was treated with initiator I (12 g), catalyst K (123 g), HPMA (29 g), HDDA (308 g), IBOMA (308 g) and INT-1940 RTM demolding agent (103 g) according to the abovementioned production method for resin mixture for pultrusion. After the preparation, the mixture had a viscosity of 611 mPas.

[0190] The glass fiber bundles (126 rovings) were oriented and guided through an injection box, which was connected to the mold in a fixed manner and was filled with the resin mixture via a window opening on the top side of the box. The glass fibers that had thus been 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 speed was 0.3 m/min and 0.5 m/min. The offtake forces were about 0.7 t. 5 m of profile were produced at each of the two speeds. The surface of the profile was homogeneous and matt, and the glass content was 80% by mass.

Working Example 6

[0191] As described above, polyisocyanate A2 (2.97 kg) was treated with initiator 1 (16 g), catalyst K (123 g), HPMA (41 g), HDDA (421 g), IBOMA (421 g) and INT-1940 RTM demolding agent (102 g) according to the abovementioned production method for resin mixture for pultrusion.

[0192] The glass fiber bundles (126 rovings) were oriented and guided through an injection box, which was connected to the mold in a fixed manner and was filled with the resin mixture via a window opening on the top side of the box. The glass fibers that had thus been 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 speed was 0.3 m/min and 0.5 m/min. The offtake forces were about 0.7 t. 5 m of profile were produced at each of the two speeds. The surface of the profile was homogeneous and matt, and the glass content was 80% by mass.

Comparative Example 7

[0193] As described above, polyisocyanate A1 (93.5 g) and catalyst K (4.0 g) were treated according to the abovementioned preparation method for reaction mixtures, and the mass was introduced into the mold. After the preparation, the mixture had a viscosity of 2180 mPas.

[0194] After curing at 220 C. for 3 min, a material with a T.sub.G of 98 C. was obtained.

Comparative Example 8

[0195] As described above, polyisocyanate A2 (93.5 g) and catalyst K (4.0 g) were treated according to the abovementioned preparation method for reaction mixtures, and the mass was introduced into the mold. After the preparation, the mixture had a viscosity of more than 10000 mPas.

[0196] After curing at 220 C. for 3 min, a material with a T.sub.G of 128 C. was obtained.

Comparative Example 9

[0197] As described above, polyisocyanate A2 (4.39 kg) was treated with catalyst K (188 g) and INT-1940 RTM demolding agent (117 g) according to the abovementioned production method for resin mixture for pultrusion. After the preparation, the mixture had a high viscosity by comparison of more than 10000 mPas. After curing at 220 C. for 3 min, a material with a T.sub.G of 126 C. was obtained.

[0198] The glass fiber bundles (126 rovings) were oriented and guided through an injection box, which was connected to the mold in a fixed manner and was filled with the resin mixture via a window opening on the top side of the box. The glass fibers thus treated 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 speed was 0.2 m/min and 0.3 m/min. The offtake forces were between about 0.4 and 0.9 t. The glass fibers came out of the mold virtually unchanged since the resin was unable to impregnate the fibers owing to the high viscosity.

Discussion

[0199] Working examples 1, 3 and 4 show that an addition of double bond-containing (acrylate-based) monomers to polyisocyanate-based reaction mixtures leads to significantly reduced starting viscosities compared to pure polyisocyanate-based reaction mixtures (cf. comparative examples 7 and 8). Such reduced starting viscosities are often helpful in the case of use of such mixtures as resins for (fiber) composite materials since they facilitate the wetting of (fibrous) fillers (see below).

[0200] Working examples 1, 3 and 4 also show that a combination of the addition reaction of isocyanate groups with the free-radical polymerization of double bond-containing monomers leads in principle to cured plastics having high glass transition temperatures.

[0201] Furthermore, working example 2 shows that such mixtures are of good suitability for embedding (fibrous) fillers without undergoing losses in material properties (e.g. Tg).

[0202] Finally, working examples 5 and 6 show that mixtures of this kind are of good suitability for continuously producing fiber composite materials with very high filler contents (>80% by mass) by means of pultrusion, whereas comparative example 9 demonstrates that excessively high starting viscosities of polymer resins prevent the continuous production of fiber composite materials.