Use of layer structures in wind power plants

Abstract

The invention relates to the use of layer structures in the production of rotor blades for wind power plants, and to rotor blades for wind power plants.

Claims

1. A process for the production of rotor blades for wind power plants comprising providing a layer structure, wherein the layer structure comprises a) a release agent layer b) a fiber layer treated with a polyurethane, c) a fiber layer provided with the polyurethane wherein at least one of the treatment of the fiber layer b) and the providing of the fiber layer c) comprises injection of a polyurethane reaction mixture through a vacuum-assisted resin transfer moulding process into a mould comprising the fiber layer b) and the fiber layer c), and wherein the polyurethane reaction mixture has a viscosity of 5000 mPas at 25 C., 30 minutes after a mixing of the polyurethane reaction mixture.

2. Process for the production of rotor blades according to claim 1 for wind power plants, comprising providing rotor blades comprising a casing comprising the layer structure.

3. Process according to claim 2, wherein the reaction mixture comprises an isocyanate diphenylmethane diisocyanate and/or polyphenylenepolymethylene polyisocyanate having an NCO content of more than 25 wt. %.

4. Process according to claim 2, wherein the reaction mixture contains a compound having at least two hydrogen atoms reactive towards isocyanate a polyether polyol in which at least 60% of the OH groups are secondary OH groups and which has an OH number of from 200 to 1830 mg KOH/g.

5. Process according to claim 2, wherein the reaction mixture is applied to the fiber layers at a temperature of from 20 to 80 C.

6. Process according to claim 2, wherein the reaction mixture is cured at a temperature of from 40 to 160 C.

7. Process according to claim 2, wherein the reaction mixture has a viscosity of 5000 mPas 30 minutes after a mixing of the reaction mixture.

8. The process according to claim 2, wherein the reaction mixture comprises an isocyanate diphenylmethane diisocyanate and/or polyphenylenepolymethylene polyisocyanate having an NCO content of more than 25 wt. %, wherein the reaction mixture contains as the compound having at least two hydrogen atoms reactive towards isocyanate a polyether polyol in which at least 60% of the OH groups are secondary OH groups and which has an OH number of from 200 to 1830 mg KOH/g, and wherein the reaction mixture has a viscosity of 5000 mPas 30 minutes after a mixing of the reaction mixture.

9. The process according to claim 8, wherein the reaction mixture has a viscosity of 2000 mPas 30 minutes after the mixing of the reaction mixture.

Description

EXAMPLES

(1) Moulded bodies (sheets) were produced from various polyurethane systems and compared with a standard epoxy resin system. The sheet size was 17 cm*17 cm, with a thickness of 4 mm.

(2) The demoulding time is the time after which the PUR test specimen can be removed from the sheet mould by hand without being deformed.

(3) The viscosity was determined 30 minutes after mixing of the components because, in the production of larger mouldings, a low viscosity is necessary for a certain time for uniform filling of the mould.

Example 1

(4) 70 g of Baygal K 55 (polyether polyol from Bayer MaterialScience AG; OH number: 38515 mg KOH/g; viscosity at 25 C.: 60050 mPas) were stirred at room temperature with 65.3 g of Baymidur K 88 (product of Bayer MaterialScience AG; mixture of diphenylmethane diisocyanate and polyphenylenepolymethylene polyisocyanate; NCO content: 31.50.5 wt. %; viscosity at 25 C.: 9020 mPas) and degassed at reduced pressure. The solution was poured into a sheet mould and stored for one hour at room temperature. The sample was then tempered at 80 C. The gelling time was about 70 minutes and the demoulding time was two hours.

(5) The test specimen had a hardness of 76 Shore D.

(6) The viscosity at 25 C. 30 minutes after mixing of the components was 1540 mPas.

Example 2

(7) 70 g of Baygal K 55 (polyether polyol from Bayer MaterialScience AG; OH number: 38515 mg KOH/g; viscosity at 25 C.: 60050 mPas) were stirred at room temperature with 63 g of Baymidur VP.KU 3-5009 (Bayer MaterialScience AG; mixture of diphenylmethane diisocyanate and polyphenylenepolymethylene polyisocyanate; NCO content: 31.5-33.5 wt. %; viscosity at 25 C.: 15-30 mPas) and degassed at reduced pressure. The solution was poured into a sheet mould and stored for one hour at room temperature. The sample was then tempered at 80 C. The demoulding time was two hours.

(8) The test specimen had a hardness of 76 Shore D.

(9) The viscosity at 25 C. 30 minutes after mixing of the components was 974 mPas.

Comparison Example 3

(10) 180 g of Larit RIM 135 (L-135i) infusion resin (product of Lange+Ritter) were stirred at room temperature with 60 g of Larit RIMH 137 curing agent (product of Lange+Ritter) and degassed at reduced pressure. The solution was poured into a sheet mould and stored for one hour at room temperature. The sample was then tempered at 80 C. The demoulding time was twelve hours.

(11) The test specimen had a hardness of 76 Shore D.

(12) The polyurethane system could be demoulded significantly more quickly. The quicker demoulding time of the polyurethane system permits higher productivity because the time for which the moulds are occupied can be markedly reduced and more moulded bodies can accordingly be produced.