INFUSION DEVICE AND METHOD FOR PRODUCING FIBER-REINFORCED COMPOSITE PARTS

Abstract

The invention relates to a method for producing fiber-reinforced composite parts by means of vacuum infusion of a reactive resin mixture, characterized in that the steps of production of the reactive resin mixture and injection into the cavity are carried out in an infusion device in immediate temporal succession.

Claims

1. A vacuum-assisted infusion process for the production of fiber-reinforced composite components, wherein a reactive resin mixture is injected into a cavity comprising a laid fiber scrim, comprising the steps of: a. providing a reaction-injection device comprising at least two feeds comprising the reactive resin components, evacuation equipment for the degassing of the feeds, a metering unit attached respectively to the feeds by way of supply lines, and a mixing unit in which the reactive resin components from the metering units are brought together, and b. providing a closed cavity comprising a laid fiber scrim, which i. is encompassed by a shell that has at least one input duct suitable for applying a vacuum to the cavity and for introducing a resin into the cavity, and ii. has at least one drying duct suitable for introducing a drying gas into the cavity in order to remove moisture from the laid fiber scrim and for applying a vacuum by using a first vacuum source for the evacuation during the infusion and optionally during the drying, and iii. has connection to the reaction-injection device at the input duct by way of an input line, where the input line is evacuatable by way of a lateral outlet which is closeable and which is attached to a second vacuum source. c. degassing and drying of the cavity and of the laid fiber scrim present therein, of the input line and optionally of the metering unit/mixing unit with the aid of the second vacuum source, where optionally a drying gas is introduced by way of the drying duct or optionally an additional evacuation takes place with the aid of the first vacuum source, d. start of an infusion procedure via introducing the degassed, reactive components from the feeds into the metering units of the reaction-injection device by way of the supply lines, and producing a reactive resin mixture from the components in the mixing unit, where the outlet to the second vacuum source is closed before said outlet is reached by the reactive resin mixture, and e. injecting the reactive resin mixture by way of the input duct into the cavity with simultaneous evacuation of the cavity with the aid of the first vacuum source by way of the drying duct, where, during the injection, an entry pressure measured at an entry point of the cavity remains lower than ambient pressure, and f. completing reaction of the resin mixture with hardening in the cavity.

2. The vacuum-assisted infusion process for the production of fiber-reinforced composite components as claimed in claim 1, wherein the process is a vacuum-assisted resin transfer molding process.

3. The process as claimed in claim 1, wherein, when a specified maximal entry pressure, measured at the entry point of the cavity, is reached, the metering unit applies control to reduce an output quantity in continuously variable fashion, whilst ensuring compliance with a maximal entry pressure.)

4. The process as claimed in claim 3, wherein the maximal entry pressure, measured at the entry point of the cavity, is 0.01 bar-0.2 bar below the ambient pressure.

5. The process as claimed in claim 3, wherein the maximal entry pressure is between 0.88 and 0.92 bar absolute.

6. The process as claimed in claim 1, wherein the input line additionally has a buffer container.

7. The process as claimed in claim 6, where the buffer container is an elastic bladder.

8. The process as claimed in claim 1, wherein the fiber-reinforced composite component is a wind turbine rotor blade and the resin comprises polyurethane resins, unsaturated polyester resins, vinyl ester resins, hybrid resins, epoxy resins, or a combination thereof.

9. The process as claimed in claim 1, wherein the resin is a polyurethane-polyacrylic hybrid resin and the reactive resin components are an isocyanate component and an isocyanate-reactive component comprising a polyol and a hydroxy-terminated (meth)acrylate monomer.

10. The use of the process as claimed in claim 1 for the production of rotor blades for wind turbines.

11. An infusion device comprising a. a reaction-injection device comprising at least two feeds comprising reactive resin components, evacuation equipment for degassing the feeds, a metering unit attached respectively to the feeds by way of supply lines, and a mixing unit in which the reactive resin components from the metering units are brought together, and b. a closed cavity comprising a laid fiber scrim, which i. is encompassed by a shell that has at least one input duct suitable for applying a vacuum to the cavity and for introducing resin into the cavity, and ii. has at least one drying duct suitable for introducing a drying gas into the cavity in order to remove moisture from the laid fiber scrim and for applying a vacuum by using a first vacuum source for the evacuation during the infusion and optionally during the drying, and iii. has connection to the reaction-injection device at the input duct by way of an input line, where this input line is evacuatable by way of a lateral outlet which is closeable and which is attached on a second vacuum source.

Description

[0055] The invention is illustrated below by way of example on the basis of a preferred working example of the infusion device, with reference to the two drawings attached; an aspect of the invention can be represented either by any of the individual features set out below or else by said features in combination.

[0056] FIG. 1 Infusion device

[0057] Reaction-injection device 40

[0058] Feeds for the resin components 48, 49

[0059] Evacuation equipment 50 for the feeds

[0060] Supply lines 41, 42

[0061] Metering units 44a, 44b

[0062] Mixing unit 43

[0063] Cavity 10

[0064] Fiber-reinforced composite component 20

[0065] Laid fiber scrim 21

[0066] Input duct 31

[0067] Drying duct 32

[0068] Drying gas 33

[0069] First vacuum source 34

[0070] Input line 45

[0071] Outlet 46

[0072] Second vacuum source 47

[0073] FIG. 2 Infusion device with buffer container

[0074] Reaction-injection device 40

[0075] Feeds for the resin components 48, 49

[0076] Evacuation equipment 50 for the feeds

[0077] Supply lines 41, 42

[0078] Metering units 44a, 44b

[0079] Mixing unit 43

[0080] Cavity 10

[0081] Fiber-reinforced composite component 20

[0082] Laid fiber scrim 21

[0083] Input duct 31

[0084] Drying duct 32

[0085] Drying gas 33

[0086] First vacuum source 34

[0087] Input line 45

[0088] Outlet 46

[0089] Second vacuum source 47

[0090] Buffer container 51

[0091] The infusion device and the process according to the invention can advantageously be utilized for the production of large composite components, e.g. for the production of rotor blades for wind turbines made of resins based on polyurethane polymers, on hybrid polymers, on unsaturated polyester polymers, on vinyl ester polymers and/or on epoxy polymers.

[0092] In a preferred embodiment, the resin used in the process according to the invention is a polyurethane-polyacrylic hybrid resin, and the reactive resin components are an isocyanate component and an isocyanate-reactive component comprising a polyol and a hydroxy-terminated acrylate monomer or hydroxy-terminated (meth)acrylate monomer.