COMPOSITE SEMI-FINISHED PRODUCTS, MOLDED PARTS PRODUCED THEREFROM, AND DIRECTLY PRODUCED MOLDED PARTS BASED ON HYDROXY-FUNCTIONALIZED (METH)ACRYLATES AND URETDIONES THAT ARE CROSS-LINKED IN A THERMOSETTING MANNER

Abstract

The invention relates to a process for producing storage-stable polyurethane prepregs and mouldings produced therefrom (composite components). For production of the prepregs or components, for example, (meth)acrylate monomers, (meth)acrylate polymers, hydroxy-functionalized (meth)acrylate monomers and/or hydroxy-functionalized (meth)acrylate polymers are mixed with non-(meth)acrylic polyols and with uretdione materials. This mixture or solution is applied to fibre material, for example carbon fibres, glass fibres or polymer fibres, by known methods and polymerized thermally, via a redox initiation or with the aid of radiation or plasma applications.

Polymerization, for example at room temperature or at up to 80° C., gives rise to thermoplastics or thermoplastic prepregs which can subsequently be subjected to a forming operation. The hydroxy-functionalized (meth)acrylate constituents and the polyols can subsequently be crosslinked with the uretdiones already present in the system by means of elevated temperature. In this way, dimensionally stable thermosets or crosslinked composite components can be produced.

Claims

1. A process for producing a semi-finished composite and further processing thereof to give a moulding, said process comprising: I. producing a reactive composition, II. directly impregnating a fibrous carrier with the composition from I., III. curing the resin component in the composition by thermal initiation, redox initiation of a two-component system, electromagnetic radiation, electron beams or a plasma, IV. shaping to give the moulding and V. curing an isocyanate component in the composition, wherein the composition comprises: A) a reactive (meth)acrylate-based resin component, wherein at least one constituent of the resin component has a hydroxyl, amine and/or thiol group, B) at least one di- or polyisocyanate which has been internally blocked and/or blocked with a blocking agent as isocyanate component, and C) one or more polyols which are not (meth)acrylates or poly(meth)acrylates.

2. The process according to claim 1, wherein the composition contains 25% to 85% by weight of the resin component, 10% to 60% by weight of the isocyanate component and 3% by weight to 40% by weight of one or more polyols.

3. The process according to claim 1, wherein the resin component comprises at least 0% by weight to 30% by weight of crosslinker, 30% by weight to 100% by weight of monomers, and 0% by weight to 40% by weight of poly(meth)acrylates.

4. The process according to claim 1, wherein the resin component comprises at least 2% by weight to 10% by weight of di- or tri(meth)acrylates, 40% by weight to 60% by weight of (meth)acrylate monomers, 0% by weight to 20% by weight of urethane (meth)acrylates, 5% by weight to 30% by weight of poly(meth)acrylates, and 0% by weight to 10% by weight of photoinitiator, peroxide and/or azo initiator.

5. The process according to claim 1, wherein the composition contains 10% by weight to 40% by weight of the polyol, and wherein the polyol is a low molecular weight polyol having 3 to 6 OH functionalities, a polyester having a molecular weight M.sub.n between 200 and 4000 g/mol, an OH number between 25 and 800 mg KOH/g and an acid number less than 2 mg KOH/g, a polyether having an OH number between 25 and 1200 mg KOH/g and a molar mass M.sub.w between 100 and 2000 g/mol, or a mixture of at least two of these polyols.

6. The process according to claim 5, wherein the polyester is a polycaprolactone having an OH number between 25 and 540, an acid number between 0.5 and 1 mg KOH/g and a molar mass between 240 and 2500 g/mol.

7. The process according to claim 1, wherein the fibrous carriers comprise for the most part at least one member selected from the group consisting of glass, carbon, polymers, natural fibres, and mineral fibre materials, and wherein the fibrous carriers take the form of at least one selected from the group consisting of sheetlike textile structures made from nonwoven fabric, knitted fabric, non-knitted structures, and of long-fibre or short-fibre materials.

8. The process according to claim 1, wherein di- or polyisocyanates are at least one selected from the group consisting of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate/2,4,4-trimethylhexamethylene diisocyanate (TMDI) and/or norbornane diisocyanate (NBDI), including the isocyanurates, and are used as isocyanate component, and wherein said di- or polyisocyanates have been blocked with at least one external blocking agent selected from the group consisting of ethyl acetoacetate, diisopropylamine, methyl ethyl ketoxime, diethyl malonate, ε-caprolactam, 1,2,4-triazole, phenol or substituted phenols and 3,5-dimethylpyrazole.

9. The process according to claim 1, wherein the isocyanate component additionally contains 0.01% to 5.0% by weight of a catalyst

10. The process according to claim 1, wherein the isocyanate components used are uretdiones prepared from isophorone diisocyanate hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate/2,4,4-trimethylhexamethylene diisocyanate (TMDI) and/or norbornane diisocyanate (NBDI).

11. The process according to claim 10, wherein the isocyanate component is in solid form below 40° C. and in liquid form above 125° C., has a free NCO content of less than 5% by weight and a uretdione content of 3% to 50% by weight, and wherein the isocyanate component additionally contains 0.01% to 5% by weight of at least one catalyst selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts and mixtures thereof with halogens, hydroxides, alkoxides or organic or inorganic acid anions as counterion.

12. The process according to claim 10, wherein the isocyanate component additionally contains 0.1% to 5% by weight of at least one cocatalyst selected from either at least one epoxide and/or at least one metal acetylacetonate and/or quaternary ammonium acetylacetonate and/or quaternary phosphonium acetylacetonate, and optionally auxiliaries and additives known from polyurethane chemistry.

13. The process according to claim 1, wherein the resin component, the polyols and the isocyanate component are present in such a ratio to one another that there is 0.3 to 1.0 uretdione group for every hydroxyl group in the resin component and the polyol.

14. The process according to claim 1, wherein the curing of the isocyanate component in process step V. is conducted at a temperature between 80 and 200° C.

15. A moulding produced from a semi-finished composite according to claim 1, formed from at least one fibrous carrier and at least one crosslinked reactive composition containing a cured (meth)acrylate resin, as matrix.

16. (canceled)

Description

EXAMPLES

[0118] The following glass fibre scrims/fabrics were used in the examples:

[0119] Glass filament fabric 296 g/m.sup.2-Atlas, Finish FK 144 (Interglas 92626)

[0120] The polyol used in the inventive examples is Polyol 4290 from Perstorp. This polyol is tetrafunctional, and has a hydroxyl number of 290±20 mg KOH/g and a molecular weight of about 800 g/mol.

Preparation of the Uretdione-Containing Curing Agent CA:

[0121] 119.1 g of IPDI uretdione (Evonik Degussa GmbH) were dissolved in 100 ml of methyl methacrylate, and 27.5 g of methylpentanediol and 3.5 g of trimethylolpropane were added. After adding 0.01 g of dibutyltin dilaurate, the mixture was heated to 80° C. while stirring for 4 h. Thereafter, no free NCO groups were detectable any longer by titrimetric methods. The curing agent CA has an effective latent NCO content of 12.8% by weight (based on solids).

Reactive Polyurethane Composition

[0122] Reactive polyurethane compositions having the formulations which follow were used for production of the prepregs and the composites (see tables).

Comparative Example 1

Corresponding to the Teaching from EP 2 661 459

[0123]

TABLE-US-00001 TABLE 1 Proportion Component Function (% by wt.) Manufacturer Curing agent CA uretdione-containing 53.3 (60% in MMA) curing agent (effective NCO: 7.7%) component a) Hydroxypropyl OH-containing 14.0 Evonik acrylate monomer Industries AG Laminating resin C methacrylate resin 8.2 Evonik Industries AG Methyl methacrylate monomer 22.7 Evonik (MMA) Industries AG Dibenzoyl peroxide initiator 0.9 Fluka N,N-bis(2-Hydroxy- accelerator 0.9 Aldrich ethyl)- p-toluidine

[0124] The feedstocks from Table 1 were mixed in a premixer to form a solution of the solid constituents in the monomers. This mixture can be used within about 2 to 3 h before it gelates.

[0125] To produce the prepregs, the glass fibre fabric was impregnated with the solution of the matrix materials. The prepregs were dried to constant weight in an oven at temperatures of 60° C. for 30 min. The proportion by mass of fibres was 47% by weight. The impregnated glass fibre mats were compressed at 180° C. and 50 bar for 1 h (press: Polystat 200 T from Schwabenthan) and fully crosslinked in the process. The hard, stiff, chemical-resistant and impact-resistant composite components (sheet material) had a T.sub.g of 119° C.

Comparative Example 2

Corresponding to the Teaching from PCT/EP2014/053705

[0126]

TABLE-US-00002 TABLE 2 Proportion Component Function (% by wt.) Manufacturer Curing agent CA uretdione-containing 53.3 (60% in MMA) curing agent (effective NCO: 7.7%) component a) Hydroxypropyl OH-containing 14.0 Evonik acrylate monomer Industries AG Laminating resin C methacrylate resin 8.2 Evonik Industries AG Methyl methacrylate monomer 22.7 Evonik (MMA) Industries AG Irgacure 819 photoinitiator 1.8 Ciba

[0127] The feedstocks from Table 2 were mixed in a premixer to form a solution of the solid constituents in the monomers. This mixture can be stored for about 1 to 2 years without gelation.

[0128] To produce the prepregs, the glass fibre fabric was impregnated with the solution of the matrix materials. The prepregs were irradiated at 1.5 m/min with a UV-LED lamp (Heraeus NobleCure® based on water-cooled heat sink, wavelength: 395±5 nm, power density: 8 W/cm.sup.2 at working distance 5 mm, emission window: 251×35 mm.sup.2) and dried in the process. The proportion by mass of fibres was 54% by weight. The impregnated glass fibre mats were compressed at 180° C. and 50 bar for 1 h (press: Polystat 200 T from Schwabenthan) and fully crosslinked in the process. The hard, stiff, chemical-resistant and impact-resistant composite components (sheet material) had a Tg of 123° C.

Comparative Example 3

Corresponding to the Teaching from PCT/EP2014/053705

[0129]

TABLE-US-00003 TABLE 3 Proportion Component Function (% by wt.) Manufacturer Curing agent CA uretdione-containing 63.0 (60% in MMA) curing agent (effective NCO: 7.7%) component a) Hydroxypropyl OH-containing 14.0 Evonik acrylate monomer Industries AG Isobornyl monomer 21.0 Evonik methacrylate Industries AG Irgacure 819 photoinitiator 2.0 Ciba

[0130] The feedstocks from Table 3 were mixed in a premixer to form a solution of the solid constituents in the monomers. This mixture can be stored for at least 1 to 2 days without gelation.

[0131] To produce the prepregs, the glass fibre fabric was impregnated with the solution of the matrix materials. The prepregs were irradiated at 1.5 m/min with a UV-LED lamp (Heraeus NobleCure® based on water-cooled heat sink, wavelength: 395±5 nm, power density: 8 W/cm.sup.2 at working distance 5 mm, emission window: 251×35 mm.sup.2) and dried in the process. The proportion by mass of fibres was 50% by weight. The impregnated glass fibre mats were compressed at 170° C. and 15 bar for 1 h (press: Polystat 200 T from Schwabenthan) and fully crosslinked in the process. The hard, stiff, chemical-resistant and impact-resistant composite components (sheet material) had a Tg of 98° C. Interlaminar shear strength of the laminate was 15 MPa.

Example 1

[0132]

TABLE-US-00004 TABLE 4 Proportion Component Function (% by wt.) Manufacturer Curing agent CA uretdione-containing 74.0 (60% in MMA) curing agent (effective NCO: 7.9%) component a) Hydroxypropyl OH-containing 11.0 Evonik methacrylate monomer Industries AG Polyol 4290 polyol 13.0 Perstop Dibenzoyl peroxide initiator 2.0 Fluka

[0133] The feedstocks from Table 4 were mixed in a premixer to form a solution of the solid constituents in the monomers. This mixture can be used within about 24 hours before it gelates.

[0134] To produce the prepregs, the glass fibre fabric was impregnated with the solution of the matrix materials and then rolled up together in a film sandwich. The supply of film prevented contact of air with the matrix. However, there are only slight differences in this regard from the comparative tests. Corresponding performance of the comparative tests gave products having a somewhat lower fibre content and a tendency toward an increase in glass transition temperature of the matrix material by a few degrees Celsius.

[0135] The prepregs together with the film were polymerized in an oven at a temperature of 60° C. for 60 min. The proportion by mass of fibres was determined in Example 1 to be 40%. The impregnated glass fibre mats were compressed at 170° C. and 15 bar for 1 h (press: Polystat 200 T from Schwabenthan) and fully crosslinked in the process. The hard, stiff, chemical-resistant and impact-resistant composite components (sheet material) had a Tg of 105° C. Interlaminar shear strength of the laminate was 71 MPa.

Example 2

[0136]

TABLE-US-00005 TABLE 5 Proportion Component Function (% by wt.) Manufacturer Curing agent CA uretdione-containing 74.0 (60% in MMA) curing agent (effective NCO: 7.9%) component a) Hydroxypropyl OH-containing 11.0 Evonik methacrylate monomer Industries AG Polyol 4290 polyol 13.0 Perstop Dibenzoyl peroxide initiator 1.0 Fluka Irgacure 819 photoinitiator 1.0 Ciba

[0137] The feedstocks from Table 5 were mixed in a premixer to form a solution of the solid constituents in the monomers. This mixture can be used for several hours with exclusion of light at room temperature before it gelates.

[0138] To produce the prepregs, the glass fibre fabric was impregnated with the solution of the matrix materials and then rolled up together in a film sandwich. Then the prepregs together with the film were irradiated at 1.5 m/min with a UV-LED lamp (Heraeus NobleCure® based on water-cooled heat sink, wavelength: 395±5 nm, power density: 8 W/cm.sup.2 at working distance 5 mm, emission window: 251×35 mm.sup.2) and dried in the process. Subsequently, further polymerization was effected in an oven at a temperature of 60° C. for 30 min. The proportion by mass of fibres was determined in Example 2 to be a content of 40% by weight.

[0139] The impregnated glass fibre mats were compressed at 170° C. and 15 bar for 1 h and fully crosslinked in the process. The hard, stiff, chemical-resistant and impact-resistant composite components (sheet material) had a Tg of 120° C.

[0140] Comparing the comparative examples to the inventive examples, the following improvements were achieved: [0141] 1. Lowering the pressure from 50 Pa (comparative examples) to 15 Pa in the inventive examples [0142] 2. Improving the interlaminar shear strength (ILSS) from 15 MPa in the comparative examples to 71 in the inventive examples [0143] 3. Achieving higher glass transition temperatures with simultaneously lower melt viscosities.