CURABLE EPOXIDE/POLYURETHANE HYBRID RESIN SYSTEM FOR SMCS

Abstract

The present invention relates to a curable epoxide/polyurethane hybrid resin system comprising an epoxide resin, a polyurethane and a latent curing agent for the epoxide resin and having a viscosity which makes the hybrid resin system suitable for use in the SMC (sheet molding compound) range. The invention also relates to the use of said resin systems for smc applications, to methods for producing fiber-reinforced composite materials using the claimed resin systems and to the thus obtained fiber-reinforced composite material and construction and moulding materials.

Claims

1. A curable epoxy/polyurethane hybrid resin system for SMC (sheet molding compound), characterized in that the hybrid resin system comprises: (1) at least one epoxy resin, (2) at least one polyurethane; wherein the at least one polyurethane is obtainable by reacting a reaction mixture comprising: (a) at least one polyisocyanate; (b) at least one polyol; and (c) at least one catalyst for the synthesis of polyurethane; and (3) at least one latent curing agent for the epoxy resin; wherein the hybrid resin system at a temperature of 150 C. has a viscosity of at least 100 Pas.

2. The hybrid resin system according to claim 1, characterized in that the at least one epoxy resin is a prepolymer based on at least one glycidyl ether, in particular an aromatic diglycidyl ether, particularly preferably a bisphenol diglycidyl ether.

3. The hybrid resin system according to claim 1, characterized in that the at least one polyisocyanate is an aromatic polyisocyanate, in particular methylene diphenyl diisocyanate (MDI) or polymeric methylene diphenyl diisocyanate (PMDI).

4. The hybrid resin system according to claim 1, characterized in that the at least one polyol is selected from the group consisting of polyether polyol, polyester polyol and mixtures thereof and/or at least one triol is contained as polyol.

5. The hybrid resin system according to claim 4, characterized in that the at least one polyol (a) is selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol and mixtures thereof, preferably from the group consisting of polyethylene glycol, polypropylene glycol and mixtures thereof and more preferably is propylene glycol; and/or (b) has a number average molecular weight M.sub.n of less than 10,000 g/mol, preferably from 120 to 6000 g/mol, in particular 150 to 3000 g/mol, very particularly preferably from 180 to 1000 g/mol; and or (c) comprises at least one linear polyether polyol, in particular polyethylene glycol or polypropylene glycol, and at least one trifunctional polyol, in particular trifunctional polyether polyol.

6. The hybrid resin system according to claim 1, characterized in that (a) the latent curing agent is activated only at temperatures above 120 C.; and or (b) the polyurethane synthesis catalyst is an organotin compound, especially dibutyltin dilaurate (DBTL).

7. A use of the hybrid resin system according to claim 1 as matrix resin in SMCs.

8. A method for the production of fiber composites by means of SMC methods, characterized in that a hybrid resin system comprising: (1) at least one epoxy resin, (2) at least one polyurethane; wherein the at least one polyurethane is obtainable by reacting a reaction mixture comprising: (a) at least one polyisocyanate; (b) at least one polyol; and (c) at least one catalyst for the synthesis of polyurethane; and (3) at least one latent curing agent for the epoxy resin is pressed with a suitable fiber material at elevated temperature and is thereby cured.

9. A fiber composite obtainable according to the method of claim 8.

10. Structural or molded material containing the fiber composite material according to claim 9.

Description

EXAMPLES

[0100] First of all, all raw materials which were liquid at room temperature from Table 1 were mixed in the speed mixer for 2 minutes at 2000 revolutions per minute in vacuo. In a second step, fillers and other solid constituents were mixed in as well. After the mixture had cooled back to room temperature, the catalyst for the polyurethane reaction was mixed for 1 min at 2000 revolutions per minute under vacuum. Subsequently, the mixtures were pre-cured for 1 h at 80 C. in a convection oven. After this pre-curing, the temperature-dependent viscosity of the hybrid resin system was determined by means of a plate/plate rheometer at a heating rate of 10 K/s in the range of 20 to 200 C. in oscillation at 100 rad/s at a deformation of 1%.

TABLE-US-00001 TABLE 1 1 2 3 4 5 DER 331 (epoxy resin prepolymer) 21.31 22.83 21.97 26.74 26.74 PEG 200 5.00 3.00 PPG2000 4.90 12.81 12.32 Trifunctional polyether polyol 8.73 4.27 4.93 5.00 3.00 (Mn ~300 g/mol MDI/PMDI from Desmodur 14.37 9.20 9.92 15.32 10.12 Filler (Omyacarb 4HD) 49.00 49.10 49.13 54.10 44.90 DBTL (dibutyltin dilaurate) 0.1 0.09 0.08 0.11 0.09 Dyhard 100SH (dicyandiamide) 1.49 1.60 1.54 1.87 1.87 Dyhard UR300 (Fenuron) 0.11 0.11 0.11 0.13 0.13 Viscosity at RT OK OK OK OK OK Viscosity at 150 C. OK OK OK OK OK MDI: methylene diphenyl isocyanate PMDI: polymeric methylene diphenyl isocyanate PEG: polyethylene glycol PPG: polypropylene glycol DER 331: epoxy resin (diglycidyl ether of bisphenol A), Dow Chemical

[0101] The hybrid resin systems of Examples 1 to 5 exhibited excellent viscosity properties both at RT and at 150 C., which are particularly suitable for SMC. The hybrid resin systems of Examples 4 and 5 showed particularly advantageous material properties in the cured fiber composites.