Method of manufacturing organic matrix composite component comprising elastomeric layer

Abstract

The invention relates to a method for manufacturing an organic matrix composite part comprising at least one elastomer layer, comprising the following steps: producing a fibrous preform (100), consolidating the fibrous preform (110) with an organic matrix to obtain an organic matrix composite part, and forming a layer of the organic matrix composite part, at least one vulcanized unsaturated elastomer layer is bonded to the organic matrix composite component (130), wherein an adhesive film is interposed between the component and the bonding surface of the one or more unsaturated elastomer layers. The method comprises a step (120) of preparing a bonding surface (20a) of each unsaturated elastomer layer prior to the bonding step (130), where the preparation step comprises grafting a halogen element onto the bonding surface by a halogenation reaction.

Description

Technical Field

[0001] This invention relates to the general field of manufacturing organic matrix composite (OMC) components, specifically components comprising fiber-reinforced materials with an organic matrix. Background Technology

[0002] These components are typically made from fiber preforms impregnated with resin (especially epoxy resin), which forms an organic matrix within the fiber preform during polymerization.

[0003] In the aerospace field, several types of components, such as fan blades or fan casings, are made of organic matrix composites. These components are subjected to high levels of vibration, which can lead to vibrational instabilities (e.g., flutter) and / or reduced fatigue life under forced excitation (crosswinds, ground effects, etc.). To reduce vibration levels, it is known to impart vibration damping properties to organic matrix composite components by adding one or more layers of elastomers. US Patent Publication US 2009 / 074586 discloses the use of elastomers on organic matrix composite fan blades to introduce mechanical damping functionality into the blades.

[0004] The adhesion strength of elastomers to organic matrix composites is crucial for ensuring the intended function of the elastomer (e.g., vibration damping). To this end, surface treatments exist to increase the adhesion of elastomers to organic matrix composites, whether bonded or unbonded. These treatments can be mechanical (grinding), such as sanding or blasting, or chemical, such as applying a primer or vulcanizing agent, or surface activation (plasma).

[0005] Mechanical treatments such as grinding or sandblasting are difficult to perform on thin elastomer membranes because they can deform the membrane during the process and, in the most extreme cases, even damage it.

[0006] Even with such treatment, adhesion failure was still observed at the interface between the elastomer layer and the organic matrix composite material in adhesion tests (out-of-plane tensile strength, peel strength, etc.). From a certification perspective, this adhesion failure is unacceptable for critical components such as propellers or fan blades.

[0007] Furthermore, most known existing surface treatments have a limited lifespan, requiring processing days or even hours before the elastomer adheres to the organic matrix composite stage. This poses a significant limitation to methods for manufacturing organic matrix composite components.

[0008] Therefore, a solution is needed to improve the adhesion properties of elastomers to organic matrix composites. Summary of the Invention

[0009] Therefore, the present invention provides a method for manufacturing an organic matrix composite material component comprising at least one elastomer layer, comprising the following steps:

[0010] - Producing fiber preforms.

[0011] - The fiber preform is consolidated with an organic matrix to obtain an organic matrix composite component.

[0012] - At least one unsaturated elastomer layer is bonded to the organic matrix composite component, wherein an adhesive film is inserted between the component and the bonding surfaces of the one or more unsaturated elastomer layers.

[0013] The feature is that, prior to the bonding step, it includes a step of preparing a bonding surface for each unsaturated elastomer layer, wherein the preparation step includes grafting a halogen element onto the bonding surface by a halogenation reaction.

[0014] The preparation process involves halogenation, which saturates the unsaturated bonds on the bonding surface of the elastomer with halogens. These halogens then form polar bonds with the adhesive during bonding, thereby enhancing the adhesion of the elastomer to the organic matrix composite of the component. Therefore, it is possible to achieve cohesive failure of the elastomer that meets the certification requirements for aerospace components, while simultaneously achieving exceptionally high peel strength values.

[0015] The step of preparing the elastomeric bonding surface via halogenation also has the advantage of stability for several weeks. This greatly simplifies the manufacturing process, as it eliminates the need for an immediate bonding step to the organic matrix composite after the preparation step in the elastomeric assembly stage.

[0016] According to a specific feature of the method of the present invention, the step of preparing the bonding surface of the one or more unsaturated elastomer layers includes an electrophilic addition halogenation reaction with a dihalogen or a halide.

[0017] According to another specific feature of the method of the present invention, the step of preparing the bonding surface of the one or more unsaturated elastomer layers includes applying a trichloroisocyanuric acid solution to at least the bonding surface. The advantage of trichloroisocyanuric acid is that it is not classified as a hazardous chemical under the EU Registration, Evaluation, Authorisation of Chemicals (also known as REACH) regulation.

[0018] According to another specific feature of the method of the present invention, the thickness of the one or more elastomeric layers is greater than or equal to 0.2 mm.

[0019] The present invention also provides a method for manufacturing an organic matrix composite material component comprising at least one elastomer layer, comprising the following steps:

[0020] -The bonding surface of at least one unsaturated elastomer layer is brought into contact with a resin-impregnated fiber preform.

[0021] - The resin is converted into an organic matrix through heat treatment to obtain an organic matrix composite component comprising one or more elastomer layers.

[0022] The feature is that, prior to the contact step, it includes a step of preparing a bonding surface for each unsaturated elastomer layer, wherein the preparation step includes grafting a halogen element onto the bonding surface by a halogenation reaction.

[0023] The preparation process involves halogenation, which saturates the unsaturated bonds on the bonding surface of the elastomer with halogens. These halogens then form polar bonds with the resin during the conversion of the resin into an organic matrix. This allows for the achievement of cohesive failure of the elastomer to meet aerospace component certification requirements, while simultaneously achieving exceptionally high peel strength values.

[0024] The step of preparing the elastomeric bonding surface via halogenation also has the advantage of stability for several weeks. This greatly simplifies the manufacturing process, as the contact step is no longer required immediately after the preparation step in the elastomer assembly stage.

[0025] According to a specific feature of the method of the present invention, the production of a fiber preform is included before the contact step, and the injection of resin into the fiber preform is included after the contact step.

[0026] According to another specific feature of the method of the invention, the production of the fiber preform includes laying a layer of pre-impregnated fiber before the contact step.

[0027] According to another specific feature of the method of the present invention, the step of preparing the bonding surface of the one or more unsaturated elastomer layers includes an electrophilic addition halogenation reaction with a dihalogen or a halide.

[0028] According to another specific feature of the method of the invention, the step of preparing the bonding surface of the one or more unsaturated elastomer layers includes applying a trichloroisocyanuric acid solution to at least the bonding surface. The advantage of trichloroisocyanuric acid is that it is not classified as a hazardous chemical under the EU's Registration, Evaluation and Authorization of Chemicals (also known as REACH) regulation.

[0029] According to another specific feature of the method of the present invention, the thickness of the one or more elastomeric layers is greater than or equal to 0.2 mm. Attached Figure Description

[0030] Other features and advantages of the invention will become apparent from the description given below, which refers to the accompanying drawings illustrating examples of embodiments without limitation.

[0031] Figure 1 This is a flowchart of the steps in a method for manufacturing an organic matrix composite material component according to an embodiment of the present invention.

[0032] Figure 2 This is a flowchart of the steps in a method for manufacturing an organic matrix composite material component according to another embodiment of the present invention.

[0033] Figure 3 This is a flowchart of the steps in a method for manufacturing an organic matrix composite material component according to another embodiment of the present invention.

[0034] Figure 4A An organic matrix composite component equipped with a viscoelastic damping device is schematically and partially shown.

[0035] Figure 4B It shows what happens when subjected to vibration. Figure 4A Components. Detailed Implementation

[0036] This invention is applicable to the manufacture of any organic matrix composite parts comprising one or more elastomer layers. As used herein, "layer" refers to an elastomer with a thickness greater than or equal to 0.2 mm and which may have various geometries. Organic matrix composite parts according to the invention may be specifically fully coated with elastomer layers, or may include one or more elastomer layers or elastomer sheets disposed at specific locations within the part. The elastomers used in this invention are unsaturated elastomers, such as polyisoprene (IR), polybutadiene (BR), styrene-butadiene (SBR), butadiene-acrylonitrile (NBR), butadiene-propylene-diene (EPDM), and isobutylene-isoprene (IIR). The elastomers used are preferably vulcanized.

[0037] As explained in detail below, the adhesion of the one or more elastomer layers can be achieved by bonding with an adhesive to an already solidified organic matrix composite component, or during the solidification phase of the component's organic matrix composite, in which case the elastomer adheres directly to the resin.

[0038] According to the present invention, the manufacturing method includes the step of preparing a bonding surface for each unsaturated elastomer layer. This bonding surface preparation step is carried out via a halogenation reaction, known as an addition halogenation reaction. A halogenation reaction allows halogen atoms to react with double bonds present in the elastomer structure. Halogenation is an addition reaction in which halogen atoms add to the double bonds of the unsaturated elastomer. Therefore, the preparation of the bonding surface involves grafting a halogen element onto the bonding surface.

[0039] The halogenation reaction on unsaturated elastomers produces polarity due to the electronegativity difference between halogens and carbon atoms. Therefore, the unsaturated bonds of halogen-saturated elastomers allow for the formation of very strong polar bonds with the adhesive during the bonding stage to the solidified organic matrix composite component, or with the organic matrix composite resin during the solidification stage. Halogens can be, in particular, chlorine (Cl), fluorine (F), bromine (Br), or iodine (I).

[0040] The preparation of unsaturated elastomer bonding surfaces can be carried out via electrophilic addition halogenation reactions, particularly using dihalogens such as chlorine (Cl2), fluorine (F2), iodine (I2), bromine (Br2), or the corresponding hydrogen halides (HCl, HF, HI, HBr). The reactions are mainly carried out in the gas phase and can be conducted at room temperature and atmospheric pressure.

[0041] According to a specific feature of the method of the present invention, the step of preparing the bonding surface of the one or more unsaturated elastomer layers includes applying a trichloroisocyanuric acid solution to at least the bonding surface.

[0042] As a non-limiting example, a solution is prepared by diluting 20 grams of trichloroisocyanuric acid powder in 1 liter of solvent (ethyl acetate in this case). The resulting solution is applied to the elastomer bonding surface using a non-metallic brush until the solvent evaporates. The elastomer can then be immersed in a trichloroisocyanuric acid solution bath.

[0043] The advantage of trichloroisocyanuric acid is that it is not classified as a hazardous chemical under the EU's "Registration, Evaluation and Authorization of Chemicals" (also known as "REACH") regulation.

[0044] Elastomer bonding surfaces prepared by addition halogenation (i.e., generating polarity by grafting halogen elements onto the bonding surface) can remain stable for several weeks. This greatly simplifies the manufacturing process, as it eliminates the need for bonding to the organic matrix composite or consolidation of the organic matrix composite immediately after the elastomer assembly stage. Elastomers prepared in this way can be stored for several weeks before use.

[0045] Now refer to Figure 1 A method for manufacturing an organic matrix composite component according to an embodiment of the present invention is described, wherein an elastomer is bonded to a solidified component.

[0046] This method begins with the fabrication of a dry fiber preform (step 100). This fiber preform is intended to form a fiber reinforcement for the organic matrix composite component to be manufactured. It can be obtained using any known textile construction technique or combination of techniques. The preform can be manufactured, in particular, by stacking unidirectional or two-dimensional layers. It can also be made directly as a single piece by three-dimensional weaving. "Two-dimensional weaving" here refers to a conventional weaving method in which each weft yarn passes from one side of the warp yarn to the other, and vice versa. "Three-dimensional weaving" here refers to a weaving method in which warp yarns pass through several layers of weft yarns, or weft yarns pass through several layers of warp yarns. The preform is made of carbon fiber.

[0047] The fiber preform is then consolidated or densified (step 110), typically maintaining its shape within the cavity of an injection mold. Consolidation of the fiber preform involves filling its pores with a matrix material. This densification is performed using a well-known liquid-based method (CVL). A liquid-based method involves impregnating the preform with a liquid composition containing a matrix material precursor. This precursor is typically in the form of a polymer, such as a high-performance epoxy resin, optionally diluted in a solvent.

[0048] The precursor is converted into the matrix, i.e., its polymerization, through heat treatment, usually by heating the injection mold. After removing any solvent and crosslinking the polymer, the preform is always held in the mold cavity corresponding to the shape of the part to be produced.

[0049] Densification of fiber preforms can be achieved using the well-known resin transfer molding method. In this method, the fiber preform is placed in a mold with the same external shape as the part to be produced. Thermosetting resin is injected into the internal space of the mold containing the fiber preform. Typically, a pressure gradient is established within this internal space between the resin injection point and the resin discharge point to control and optimize the impregnation of the preform by the resin.

[0050] The resin used can be, for example, an epoxy resin with a temperature rating of 180°C (i.e., the highest temperature it can withstand without loss of performance). Resins suitable for resin transfer molding are well known. They preferably have low viscosity to facilitate fiber injection. The selection of the temperature rating and / or resin chemistry is determined based on the thermomechanical stresses the part will experience. Once the resin is injected into the entire reinforcing material, it is polymerized by heat treatment according to the resin transfer molding method.

[0051] After injection and polymerization, the organic matrix composite component is demolded.

[0052] An unsaturated elastomer layer is then bonded to the organic matrix composite component (step 130). Prior to this bonding step, the bonding surface of the unsaturated elastomer layer is prepared by addition halogenation as detailed above (step 120). Since the bonding surface preparation step is stable for several weeks, it can be performed before or after steps 100 and 110, which correspond to the production and consolidation of the fiber preform. For example, it can be performed long before the first step 100, and the prepared elastomer is stored until it is bonded to the organic matrix composite component.

[0053] Bonding involves inserting an adhesive material between the outer surface of the organic matrix composite component (which has undergone known surface treatments, such as sandblasting) and the bonding surface of the elastomeric layer. For example, the adhesive material could correspond to that made of Hysol. The company manufactures EA914 epoxy resin, which is supplied by 3M. The company manufactures AF191 adhesive film, which is supplied by Cytec. The company manufactures FM300 adhesive film or uses Hysol. The company manufactures EA9396 epoxy resin. Thermal cycling is then applied to the component to polymerize the adhesive film, completing the bonding between the elastomer layer and the component's organic matrix composite. By using a halogen-saturated elastomer to bond the unsaturated bonds on the surface, high-strength polar bonds are formed with the adhesive, significantly improving the adhesion between the elastomer and the component's organic matrix composite.

[0054] Now refer to Figure 2 A method for manufacturing an organic matrix composite material component according to another embodiment of the present invention is described. This method is similar to... Figure 1 The difference in the methods is that the adhesion of the elastomer layer occurs during the consolidation step, rather than as... Figure 1 That method will be used later.

[0055] The method begins with the production of a dry fiber preform (step 200). This fiber preform is intended to form a fiber reinforcement for an organic matrix composite component to be manufactured. It can be used for... Figure 1 Method step 100 is obtained using one of the techniques already described. Here, the preform is made of carbon fiber.

[0056] Once the fiber preform is made, an unsaturated elastomer layer is brought into contact with the preform (step 220).

[0057] Prior to this contact step, the bonding surface of the unsaturated elastomer layer is prepared by addition halogenation as detailed above (step 210). Since the bonding surface preparation step is stable for several weeks, it can be performed before or after step 200 of the fiber preform production. For example, it can be performed well before this first step 200, and the prepared elastomer is stored until it is bonded to the organic matrix composite component.

[0058] Then the resin is injected into the fiber preform (step 230), as described above. Figure 1 As detailed in step 110 of the method. The fiber preforms with the elastomer layer can maintain their shape and abut against each other, especially within the cavity of an injection mold or resin transfer molding.

[0059] Once the fiber preform is impregnated with resin, it is transformed into the matrix, i.e., its polymerization, through heat treatment (step 240), typically by heating the injection mold. After removing any solvent and crosslinking the polymer, the preform and elastomer layer remain within a mold cavity that corresponds to the shape of the part to be produced.

[0060] After injection and polymerization, the organic matrix composite component with the elastomeric layer is demolded.

[0061] By using the unsaturated bonds of the bonding surface with a halogen-saturated elastomer, high-strength polar bonds are formed between the elastomer bonding surface and the resin of the injected preform during polymerization. Therefore, the adhesion between the elastomer and the component organic matrix composite is significantly improved.

[0062] Now refer to Figure 3 A method for manufacturing an organic matrix composite material component according to another embodiment of the present invention is described. This method is similar to... Figure 1 The difference in the methods is that the adhesion of the elastomer layer occurs during the consolidation step, rather than as... Figure 1 That method will be used later.

[0063] The method begins by producing a pre-impregnated fiber preform by laying or stacking unidirectional or two-dimensional layers pre-impregnated with resin (step 300). This fiber preform is intended to form a fiber reinforcement for an organic matrix composite component to be manufactured. In this case, the preform is made of carbon fiber.

[0064] Once the preimpregnated fiber preform is formed, an unsaturated elastomer layer is brought into contact with the preform (step 320). Holding the elastomer layer on the preimpregnated preform is performed in a molding tool that allows the preform to be shaped into the final part.

[0065] Prior to this contact step, the bonding surface of the unsaturated elastomer layer is prepared by addition halogenation as detailed above (step 310). Since the preparation of the elastomer bonding surface is stable for several weeks, it can be performed before or after step 300 of the fiber preform production. For example, it can be performed well before this first step 300, and the prepared elastomer is stored until it is bonded to the organic matrix composite component.

[0066] Once contact is complete, the resin is converted into the matrix, i.e., its polymerization, through heat treatment (step 340), typically by heating, while the preform and elastomer layer are always kept in contact with each other, for example, in the molding tool.

[0067] After polymerization, the organic matrix composite component with the elastomeric layer is demolded.

[0068] By using the unsaturated bonds on the bonding surface of the halogen-saturated elastomer, high-strength polar bonds are formed between the elastomer bonding surface and the resin present in the preform during its polymerization. Therefore, the adhesion between the elastomer and the component organic matrix composite is significantly improved.

[0069] Figure 4A and Figure 4B An example of the invention applied to an organic matrix composite component equipped with a damping system is shown. In the example described herein, the organic matrix composite component 10, such as a turbine engine fan blade, is equipped with a viscoelastic damping device consisting of a stack of an elastomer layer 20 and a backing layer 30 made of a rigid material (e.g., a metallic material). The rigid material backing layer 30 may also advantageously consist of a pre-impregnated organic matrix composite material, which is laid out and then polymerized on a previously halogenated elastomer film. The polymerization step of the pre-impregnated composite backing layer can be performed prior to the step of bonding the elastomer film to the organic matrix composite component to be damped. The polymerization step can also be performed simultaneously with the resin transfer molding injection polymerization of the component to be damped if the elastomer film and the uncured pre-impregnated layer are laid out in a mold together with a dry fiber preform. The bonding surface 20a of the elastomer layer 20 is prepared by addition halogenation as described above, and thus adheres firmly to the organic matrix composite surface 10b of the component 10.

[0070] like Figure 4B As shown, vibration of the organic matrix composite component 10 causes deformation of the elastomer 20 between the component 10 and the rigid backing layer 30. Its viscoelastic properties dissipate the mechanical energy of the vibration, thus damping it. Good adhesion of the elastomer layer 20 to both the organic matrix composite component 10 and the backing layer 30 is crucial for the proper performance and durability of the damping technology. The bonding surface of the elastomer layer, prepared by halogenation, ensures that this condition is met.

[0071] Thanks to the halogenation process used to prepare the elastomeric bonding surface, cohesive failure of the elastomeric material that meets the certification requirements for aerospace components can be achieved, while simultaneously achieving exceptionally high peel strength values. Comparative tests (with and without halogenation preparation of the elastomeric bonding surface) show that preparing the elastomeric bonding surface before bonding can increase the peel strength by at least four times, reaching at least 4 N / mm (peel force per unit peel strip width).

[0072] The phrase "between... and..." should be understood to include the endpoints.

Claims

1. A method for manufacturing an organic matrix composite component (10) comprising at least one elastomeric layer (20), comprising the following steps: - Producing fiber preforms (100), - The fiber preform (110) is consolidated with an organic matrix to obtain an organic matrix composite component. - Adhere at least one unsaturated elastomer layer to the organic matrix composite component (130), wherein an adhesive film is inserted between the component and the bonding surfaces of the one or more unsaturated elastomer layers, characterized in that, prior to the bonding step (130), a step (120) is included to prepare the bonding surface (20a) of each unsaturated elastomer layer, wherein the preparation step includes grafting a halogen element onto the bonding surface by a halogenation reaction.

2. The method according to claim 1, wherein, The step of preparing the bonding surface of the one or more unsaturated elastomer layers includes applying a trichloroisocyanuric acid solution to at least the bonding surface.

3. The method according to claim 1, wherein, The step of preparing the bonding surface of the one or more unsaturated elastomer layers includes an electrophilic addition halogenation reaction with a halogen or a halogen.

4. The method according to any one of claims 1 to 3, wherein, The thickness of the at least one elastomer layer (20) is greater than or equal to 0.2 mm.

5. A method for manufacturing an organic matrix composite component (10) comprising at least one elastomeric layer (20), comprising the following steps: -The bonding surface (20a) of at least one unsaturated elastomer layer (20) is brought into contact with the fiber preform (220, 320). - The resin present in the fiber preform is converted into an organic matrix (240, 330) by heat treatment to obtain an organic matrix composite component (10) comprising one or more elastomer layers (20). The invention is characterized by comprising, prior to the contact step, a step (210, 310) of preparing a bonding surface (20a) of each unsaturated elastomer layer (20), wherein the preparation step comprises grafting a halogen element onto the bonding surface by a halogenation reaction.

6. The method of claim 5, comprising producing the fiber preform (200) prior to the contact step (220) and injecting resin into the fiber preform (230) after the contact step.

7. The method of claim 5, comprising producing a fiber preform (300) by laying a pre-impregnated fiber layer prior to the contact step (320).

8. The method according to any one of claims 5 to 7, wherein, The step of preparing the bonding surface of the one or more unsaturated elastomer layers includes applying a trichloroisocyanuric acid solution to at least the bonding surface.

9. The method according to any one of claims 5 to 7, wherein, The step of preparing the bonding surface of the one or more unsaturated elastomer layers includes an electrophilic addition halogenation reaction with a halogen or a halogen.

10. The method according to any one of claims 5 to 9, wherein, The thickness of the at least one elastomer layer (20) is greater than or equal to 0.2 mm.

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