Overmolded composite structures

Abstract

The present invention relates to an overmolded composite structure comprising: i) a first component C1 comprising at least one fibrous material and a matrix resin component comprising at least one reactive thermoplastic polymer having a number average molecular weight Mn of between 3,000 and 35,000 g / mol, preferably 5,000 and 20,000 g / mol, and optionally a chain extender or chain restrictor; the present invention relates to a method for preparing a high-molecular polymer, the method comprising the steps of: a) adding a catalyst to a solvent, the catalyst comprising: 1-10,000 g / mol; and ii) a second component C2 comprising an overmolded resin component, the first component C1 having at least one surface S, and the component C2 being adhered to the component C1 over at least a portion of the surface S.

Description

Technical Field

[0001] This invention relates to an overmolded structure comprising a composite and an overmolded thermoplastic polymer component. Background Technology

[0002] Composite materials are increasingly being used in various fields such as automotive, aerospace, and sporting goods. Hybrid structures (composite / metal, composite / polymer, or metal / polymer, etc.) are under development and are considered an interesting alternative, not only for reducing and reinforcing structures but also for providing multiple functions to manufactured parts. Notably, there is a desire to replace certain metal parts to reduce their weight and lower production costs. Such composites are particularly used to manufacture overmolded composite structures, where components are overmolded onto at least a portion of the composite's surface.

[0003] Therefore, many players in the automotive and aerospace industries have developed methods for manufacturing improved components.

[0004] For example, a localized reinforcement based on a composite (carbon fiber + thermoplastic polymer) is placed in the injection mold of an automotive part to locally and intelligently reinforce the injected component (e.g., a car door). Thus, the component is both relieved and reinforced in its preferred stress direction.

[0005] Beyond these application areas, other players in the high-tech and performance sectors have sought to adapt these new conversion technologies to their specific needs.

[0006] Therefore, there have been many developments in sports, leisure, and electronics over the past few years. For example, an increasing number of manufacturers of running shoes or athletic shoes, as well as bicycles and other competitive or recreational sports shoes, are incorporating composite reinforcement elements into their footwear. These composites allow for improved and diverse performance in their products, such as better durability, higher performance (especially energy return), and weight reduction.

[0007] These composites typically exist in the form of sheets prefabricated using conventional processes and are usually based on carbon fibers impregnated with thermosetting resins (epoxy resins), or, in rarer cases, carbon fibers impregnated with thermoplastic resins (acrylic resins, PC, PP). These composite reinforcements can then be integrated into the finished product, particularly bonded to an existing carrier, depending on the specific method used. This bonding is essential and ensures cohesion between the composite component and the overmolded polymer / elastomer (which typically do not share the same chemistry). It also allows the composite to remain in place for later stages of finished product manufacturing. Without cohesion, the composite and the overmolded product will have limited performance over time and / or will fail to meet certain fundamental performance criteria outside the production line (size and positioning in the finished product, finished product appearance, optical quality, thermal or electrical conductivity / insulation, mechanical load transfer from overmolding to the composite and vice versa, premature interface failure, etc.).

[0008] To ensure best compatibility with the components to be assembled, bonding solutions are typically based on reactive thermosetting resins (cold or hot) and / or solvents. Therefore, if they have different chemical properties, they are not entirely compatible with the two components (parts) of the overmolded composite. They are also not depolymerizable during the possible disassembly and recycling phases of the product at the end of its life.

[0009] To overcome these inconveniences, alternative solutions have been proposed:

[0010] - Prepare the surface state of the composite to make it rougher / more textured. This results in a larger contact surface, potentially leading to better quality between the composite and the adhesive. However, chemical / physical incompatibilities still exist, limiting performance and / or the duration of use while maintaining performance.

[0011] - Use thermoplastic adhesives instead of thermosetting adhesives. However, the application of these adhesives is often more complex, and very generally, they are only compatible with one of the two components to be assembled.

[0012] - Surface treatment is used to functionalize one or two surfaces to improve their compatibility. However, this step, which typically consists of plasma treatment (cold or hot), is expensive and has a short lifespan (at most a few hours).

[0013] US2012108122 discloses composite structures that do not require the use of adhesives in overmolding. However, heating the composite to near its melting temperature before the overmolding step can damage the physical properties of the composite, particularly its degree of consolidation, and affect the mechanical properties of the final workpiece.

[0014] Therefore, there is a real need to provide a composite material compatible with the overmolding polymer layer, thereby allowing the elimination of any additional adhesive primer between the composite material and the overmolded component. There is also a real need to provide a composite material that is compatible with the overmolding polymer layer and allows good adhesion between the composite material and the overmolding layer, particularly allowing peel strength greater than 50 N / cm, preferably greater than or equal to 70 N / cm, and particularly preferably greater than or equal to 100 N / cm. Summary of the Invention

[0015] This invention mainly relates to a molded composite structure comprising:

[0016] i) A first component (C1) comprising at least one fibrous material and a matrix resin component, said matrix resin component comprising at least one reactive thermoplastic polymer and possibly a chain extender and / or chain restrictor and / or catalyst and / or one or more additives, said thermoplastic polymer having a number-average molecular weight Mn between 3,000 and 35,000 g / mol, preferably between 5,000 and 20,000 g / mol, more preferably between 5,000 and 15,000 g / mol, and more preferably between 5,000 and 10,000 g / mol; and

[0017] ii) A second component (C2) comprising a coating molding resin component, wherein the first component (C1) comprises at least one surface (S), and the component C2 is adhered to the component (C1) on at least a portion of the surface (S).

[0018] Preferably, the at least one reactive thermoplastic polymer is a polyamide, polycarbonate, or polymethacrylate, preferably a polyamide, and may include epoxy groups, preferably a polyamide.

[0019] Preferably, the at least one reactive thermoplastic polymer is selected from:

[0020] -Aliphatic polyamides selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010, and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and polyether amide or polyether ester amide copolymers (PEBA) (or copolymers of polyamide blocks and polyether blocks), or

[0021] - Semi-aromatic polyamides are semi-aromatic polyamides that can be modified by urea units, particularly PA MXD6 and PA MXD10 or semi-aromatic polyamides of formula A / XT, wherein A is selected from a motif obtained from at least one amino acid, a motif obtained from at least one lactam, and at least one motif corresponding to the formula (diamine of Ca).(diacid of Cb), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18, and the motif (diamine of Ca) is selected from linear or branched aliphatic diamines. Alicyclic diamines and alkyl aromatic diamines, wherein the molar (diacid of Cb) is selected from linear or branched alicyclic diacids and aromatic diacids; XT represents the molar obtained by polycondensation of the diamine of Cx and terephthalic acid, wherein x represents the number of carbon atoms of the diamine of Cx, x is between 6 and 36, advantageously between 9 and 18, particularly polyamides of the formula A / 6T, A / 9T, A / 10T or A / 11T, and A is, for example, as defined above, particularly polyamide PA. 6 / 6T, PA66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 10T, where T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane.

[0022] Preferably, the at least one reactive thermoplastic polymer is selected from:

[0023] -Aliphatic polyamides selected from polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and polyether amide or polyether ester amide copolymers (PEBA) (or copolymers of polyamide blocks and polyether blocks), or

[0024] - Semi-aromatic polyamides that may be modified by urea units, particularly PA MXD6 and PA MXD10 or semi-aromatic polyamides having the formula A / XT, wherein A is selected from a moiety obtained from at least one amino acid, a moiety obtained from at least one lactam, and at least one moiety corresponding to the formula (diamine of Ca).(diacid of Cb), wherein a represents the number of carbon atoms in the diamine, and b represents the number of carbon atoms in the diacid, a and b being respectively between 4 and 36, advantageously between 9 and 18, and the moiety (diamine of Ca) is selected from linear or branched aliphatic diamines, alicyclic... Diamines and alkyl aromatic diamines, and the molar (diacid of Cb) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; XT represents the molar obtained by polycondensation of the diamine of Cx and terephthalic acid, where x represents the number of carbon atoms of the diamine of Cx, x is between 6 and 36, advantageously between 9 and 18, especially polyamides of the formula A / 6T, A / 9T, A / 10T, or A / 11T, and A is, for example, as defined above, especially polyamide PA. 6 / 6T, PA 66 / 6T, PA 6I / 6T, PAMPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PABACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 10T; T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane.

[0025] Preferably, the reactive thermoplastic polymer is a semi-aromatic polyamide selected from PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, and PA 11 / MXDT / 10T.

[0026] Preferably, the reactive thermoplastic polymer is PA11 or PA12, with PA11 being more preferred.

[0027] Preferably, the resin composition of the overmolded resin is the same as or different from that of the matrix resin, and preferably it contains an aliphatic polyamide polymer or a semi-aromatic polymer as defined above.

[0028] Preferably, the fiber material comprises fibers selected from:

[0029] - Mineral-derived fibers, such as carbon fiber, glass fiber, silicon carbide fiber, basalt fiber, and silica fiber;

[0030] - Plant-derived fibers, especially those based on flax, hemp, lignin, bamboo, silk, especially spider silk, or sisal, and cellulose fibers, especially viscose.

[0031] - Organic source fibers, such as amorphous thermoplastic fibers, having a glass transition temperature (Tg) higher than the Tg of the polymer of the matrix resin component (when the polymer of the matrix resin component is amorphous) or higher than the Tf of the polymer of the matrix resin component (when the polymer of the matrix resin component is semi-crystalline), and whose Tg (in the amorphous case) or Tf (in the semi-crystalline case) is higher than the injection temperature of the overmolding resin component; or semi-crystalline thermoplastic fibers, having a melting temperature (Tf) higher than the Tg of the polymer of the matrix resin component (when the matrix resin component is amorphous) or higher than the Tf of the polymer of the matrix resin component, and whose Tg (in the amorphous case) or Tf (in the semi-crystalline case) is higher than the injection temperature of the overmolding resin component; or mixtures of two or more of the aforementioned fibers, preferably mixtures of carbon fibers, glass fibers, or silicon carbide fibers, particularly carbon fibers.

[0032] Or a mixture thereof.

[0033] Preferably, the overmolded composite structure does not contain an adhesive primer between components C1 and C2.

[0034] Preferably, the matrix resin component does not contain filler or contains less than 2% by weight, preferably 0.01% to 0.5% by weight, of filler relative to the weight of the matrix resin component.

[0035] Preferably, the reactive thermoplastic polymer is reacted at 1800 s. -1 The melt viscosity measured in capillary rheology under shear is between 0.05 and 1000 Pa·s, preferably between 0.1 and 1000 Pa·s, more preferably between 0.3 and 1000 Pa·s, more preferably between 0.3 and 500 Pa·s, even more preferably between 0.3 and 250 Pa·s, for example between 0.3 and 100 Pa·s, even more preferably between 0.3 and 50 Pa·s, even more preferably between 0.3 and 25 Pa·s, even more preferably between 0.3 and 10 Pa·s, preferably between 0.3 and 5 Pa·s.

[0036] Preferably, the reactive thermoplastic polymer is an amorphous polyamide or a semi-crystalline polyamide, whose absolute value of the melting enthalpy in the component (C1) prior to overmolding is less than 12 J / g matrix resin, preferably less than 8 J / g matrix resin, and more preferably less than 5 J / g matrix resin, calculated according to equation (1).

[0037] Equation (1):

[0038]

[0039] Enthalpy was measured by differential scanning calorimetry (DSC) according to ISO 11357-3 standard 2013. The melting peak and crystallization peak were the first heating peaks at a rate of 20 K / min.

[0040] Preferably:

[0041] - The matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises PEBA; or

[0042] - The matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11; or

[0043] - The matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises a semi-aromatic polyamide; or

[0044] - The matrix resin comprises a semi-aromatic polyamide, and the overmolding resin comprises a lipid polyamide, preferably PA11 or PA12, with PA11 being more preferred.

[0045] The present invention also relates to a method for manufacturing a composite structure for overmolding according to the invention, comprising the step of overmolding component C2 onto at least a portion of the surface S of component C1.

[0046] Preferably, the overmolding step is an injection overmolding step.

[0047] This application also relates to the use of the overmolded composite structure according to the invention for manufacturing parts, particularly in the fields of machinery, aviation, marine, automotive, oil and gas (especially offshore and gas storage), energy, health and medical, sports and leisure, and electronics.

[0048] This application also relates to the use of the matrix resin composition according to the invention for preparing a molded composite structure comprising a first component (C1) and a second component (C2) to obtain a peel strength between the components (C1) and (C2) greater than or equal to 50 N / cm, preferably greater than or equal to 70 N / cm, and particularly preferably greater than or equal to 100 N / cm, as measured according to a suitable scheme (90° peel) of ISO 4578:1997, wherein the first component (C1) comprises at least one fibrous material and the matrix resin composition, and the second component (C2) comprises a molded resin composition. Attached Figure Description

[0049] Figure 1 The image shows a DSC thermogram of component C1 according to the invention, obtained using a matrix resin containing a semi-aromatic polyamide. The image corresponds to the first heating of the DSC analysis procedure and displays the area under the first heating peak (A) corresponding to the first heating crystallization peak and the area under the first heating melting peak (B). Enthalpy measurements were performed by differential scanning calorimetry (DSC) according to ISO 11357-3 (2013), where the melting and crystallization peaks are the first heating peaks at a rate of 20 K / min.

[0050] Figure 2 This is a representative image of the test sample prepared in Example 2. Detailed Implementation

[0051] The invention will now be described in more detail in a non-limiting manner in the following description.

[0052] Unless otherwise specified, all percentages are by mass.

[0053] In this text, the amount indicated for a given substance may be applied to that substance according to all its definitions (such as those mentioned in this text), including more restrictive definitions.

[0054] In this specification, "fiber material" refers to a set of integral reinforcing fibers.

[0055] Thermoplastic or thermoplastic polymers are materials that are normally solid at room temperature, can be semi-crystalline or amorphous, and soften as the temperature rises, especially after passing their glass transition temperature (Tg). When amorphous, they flow at even higher temperatures, or when semi-crystalline, they exhibit a clear melt at their so-called melting temperature (Tf), and become solid again when the temperature drops below their crystallization temperature (for semi-crystalline) and below their glass transition temperature (for amorphous).

[0056] Tg and Tf were determined by differential scanning calorimetry (DSC) according to ISO 11357-2:2013 and 11357-3:2013, respectively.

[0057] Overmolded composite structures

[0058] This invention mainly relates to a molded composite structure comprising:

[0059] i) A first component (C1) comprising at least one fibrous material and a matrix resin component, said matrix resin component comprising at least one reactive thermoplastic polymer and possibly a chain extender and / or chain restrictor and / or catalyst and / or one or more additives, said thermoplastic polymer having a number-average molecular weight Mn between 3,000 and 35,000 g / mol, preferably between 5,000 and 20,000 g / mol, preferably between 5,000 and 15,000 g / mol, preferably between 5,000 and 10,000 g / mol; and

[0060] ii) Second component (C2), which comprises a coating molding resin component,

[0061] The first component (C1) includes at least one surface (S), and the component (C2) is adhered to the component (C1) on at least a portion of the surface (S).

[0062] It should be understood that the first component (C1) can be of any shape, 2D or 3D, and in particular can be a parallelepiped shape, or a more complex 2D or 3D shape, and thus may contain several surfaces (S). A component (C2) is adhered to the component (C1) on at least one of its surfaces (S). The invention also includes cases where the component (C2) is adhered to the component (C1) on several different surfaces (S), which may be the same or different depending on the surfaces (S).

[0063] In a particularly advantageous manner, the inventors have shown that a specific selection of the matrix resin composition allows for good cohesion and particularly good adhesion (or “cohesion”) between components (C1) and (C2) without the need for an adhesion primer between components (C1) and (C2). In a particularly advantageous manner, the inventors have shown that a specific selection of the matrix resin composition allows for good adhesion between components (C1) and (C2), characterized by a peel strength, measured according to a suitable scheme (90° peel) of ISO 4578:1997, greater than or equal to 50 N / cm, preferably greater than or equal to 70 N / cm, and particularly preferably greater than or equal to 100 N / cm.

[0064] Overmolding includes molding products (here, components (C1)). It should be understood that the composite structure of overmolding differs from the association of two impregnated fibrous materials. Unlike the impregnated fibrous materials, the overmolding resin component cannot contain continuous fibers. In fact, the presence of continuous fibers would render it unusable in overmolding processes, such as injection overmolding.

[0065] Overmolding includes molding a second component (C2) in a mold containing a preformed component (C1), wherein if the component (C2) comprises an amorphous polymer, the second component (C2) is introduced at a temperature above the glass transition temperature of the component (C2), or if the component (C2) comprises a semi-crystalline polymer, the second component (C2) is introduced at a temperature above the melting temperature of the component (C2).

[0066] Matrix resin components

[0067] The term "reactive thermoplastic polymer" refers to a thermoplastic polymer that can react with the overmolding resin, or may react with itself through condensation to release water, or through substitution, or through reaction with a chain extender via addition or condensation polymerization. In a particularly advantageous manner, the polymer can react with the overmolding resin via its terminal functional groups, or even through exchange reactions between its respective repeating units, or even through reactions between its repeating units and its terminal functional groups. Optionally, this reaction is made possible by adding additives.

[0068] When this "reactive thermoplastic polymer" reacts with itself, it exhibits an initial number-average molecular weight Mn1 and an initial melt viscosity ƞ1. When its temperature is above its glass transition temperature, and particularly above its melting temperature, the substance evolves through its own reaction, meaning that the polymer produced by the reaction of the reactive thermoplastic polymer with itself has a number-average molecular weight Mn2 and a melt viscosity ƞ2 greater than or equal to the initial molecular weight Mn1 and the initial melt viscosity ƞ1. Preferably, Mn2 is at least 5% greater than Mn1, more preferably at least 10% greater.

[0069] In the following text, we will refer to the number-average molecular weight of a reactive thermoplastic polymer as the number-average molecular weight of the thermoplastic polymer (if it does not react with itself) or the number-average molecular weight (Mn2) of the polymer produced by its reaction with itself. Similarly, in the following text, we will refer to the melt viscosity as the viscosity of the thermoplastic polymer (if it does not react with itself) or the viscosity (ƞ2) of the polymer produced by its reaction with itself.

[0070] The chain extender may be any type of chain extender known to those skilled in the art, such as those cited in patent application FR1907685.

[0071] These number-average molecular weights should be understood as those in a solid state after the polymer is cooled.

[0072] Preferably, the reactive thermoplastic polymer is a polyamide, polycarbonate, or polymethacrylate, with polyamide being preferred. Optionally, it includes epoxy functional groups.

[0073] Preferably, the reactive polymer is a polyamide, particularly an aliphatic, alicyclic, or semi-aromatic polyamide.

[0074] Advantageously, the reactive thermoplastic polymer is a homopolymer or a copolymer or a mixture thereof.

[0075] The number-average molecular weight (Mn) of the reactive thermoplastic polymer is between 3,000 and 35,000 g / mol, preferably between 5,000 and 20,000 g / mol, more preferably between 5,000 and 15,000 g / mol, and even more preferably between 5,000 and 10,000 g / mol. This number-average molecular weight can be determined, in particular, by size exclusion chromatography according to ISO 16014-1:2012, 16014-2:2012 and 16014-3 standards, using the following conditions:

[0076] - Apparatus: Waters Alliance 2695 instrument

[0077] Solvent: Hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate

[0078] - Flow rate: 1 mL / min

[0079] - Column temperature: 40℃.

[0080] - Two columns in series: 1000ÅPFG and 100ÅPFG(PPS)

[0081] - Sample concentration: 1 g / L (dissolved at room temperature for 24 hours)

[0082] - Sample filtration was performed using a syringe equipped with an Acrodisc PTFE filter with a diameter of 25 mm and a porosity of 0.2 μm.

[0083] Injection volume: 100 μL

[0084] - Refractive index was measured at 40°C using UV detection at 228nm.

[0085] - Calibrated to 1,900,000 g / mol to 402 g / mol using PMMA standards. The calibration curves were modeled using a fifth-order polynomial.

[0086] Advantageously, the composite obtained with such a matrix allows for obtaining a more improved adhesion to the overmolded matrix, particularly resulting in an even greater peel strength.

[0087] Preferably, the melt viscosity of the at least one reactive thermoplastic polymer measured in capillary rheology under a shear of 1800 s -1 is between 0.05 and 1000 Pa·s, preferably between 0.1 and 1000 Pa·s, preferably between 0.3 and 1000 Pa·s, preferably between 0.3 and 500 Pa·s, more preferably between 0.3 and 250 Pa·s, such as between 0.3 and 100 Pa·s, even more preferably between 0.3 and 50 Pa·s, more preferably between 0.3 and 25 Pa·s, even more preferably between 0.3 and 10 Pa·s, preferably between 0.3 and 5 Pa·s. The melt viscosity is measured by capillary rheology using a Gottfert Rheotester 2000 device. The measurement temperature (T) follows the inequality Tf < T ≤ Tf + 70 °C. The measurement is carried out according to ISO 11443:2014. The preheating time is 240 seconds, the die has a diameter of 1 mm and a length of 30 mm. Shear and viscosity are corrected by Rabinowitsch. Preferably, the melt viscosity is preferably measured at Tf + 50 °C, where Tf is the melting temperature of the at least one polyamide. Advantageously, the composite obtained with such a matrix allows for obtaining an even more improved adhesion to the overmolded matrix, particularly resulting in an even greater peel strength.

[0088] The reactive thermoplastic polymer of the matrix resin constituting the fibrous material can be composed of a mixture of thermoplastic polymers, where at least one thermoplastic polymer is reactive. The polymer or polymer mixture can be ground into powder form so as to be able to be used in devices such as tanks, particularly in a fluidized bed or in an aqueous or solvent dispersion.

[0089] The device in the form of a tank, particularly in the form of a fluidized bed, can be open or closed.

[0090] Optionally, the matrix resin further contains a carbon filler, particularly carbon black or carbon nano-fillers, preferably selected from carbon nano-fillers, particularly graphene and / or carbon nanotubes and / or carbon nanofibrils or mixtures thereof. These fillers allow for electrical and thermal conduction and thus promote the melting of the matrix upon heating.

[0091] Optionally, the reactive thermoplastic polymer contains at least one additive, particularly selected from catalysts, antioxidants, heat stabilizers, UV stabilizers, light stabilizers, lubricants, fillers, plasticizers, flame retardants, nucleating agents, dyes, conductive agents, heat conductive agents or mixtures thereof.

[0092] Advantageously, the additive is selected from flame retardants, conductive agents, and thermal conductive agents.

[0093] The flame retardant may be a halogen-free flame retardant, such as those described in US 2008 / 0274355, and particularly selected from metal salts of hypophosphonic acids, metal salts of secondary phosphonic acids, polymers containing at least one metal salt of hypophosphonic acid, polymers containing at least one metal salt of secondary phosphonic acid, or metal salts of red phosphorus, antimony oxide, zinc oxide, iron oxide, magnesium oxide, or metal borates such as zinc borate, or even melamine pyrophosphate and melamine cyanurate. They may also be halogenated flame retardants, such as brominated or polybrominated polystyrene, brominated polycarbonate, or brominated phenol.

[0094] Advantageously, the reactive thermoplastic polymer is a polyamide, and is selected from aliphatic polyamides, alicyclic polyamides, and semi-aromatic polyamides (polyphthalamides).

[0095] Preferably,

[0096] - The aliphatic polyamide is selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and polyether amides or polyether ester amide copolymers ( PEBA (or block copolymers having polyamide and polyether blocks), preferably selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof, and

[0097] - The semi-aromatic polyamide is a semi-aromatic polyamide that may be modified by a urea unit, particularly a semi-aromatic polyamide of the formula X / YAr, such as that described in EP1505099, particularly a semi-aromatic polyamide of the formula A / XT, wherein A is selected from a moiety obtained from at least one amino acid, a moiety obtained from at least one lactam, and at least one moiety corresponding to the formula (diamine of Ca). (diacid of Cb), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18, the moiety (diamine of Ca) is selected from linear or branched aliphatic diamines, alicyclic diamines and alkyl aromatic diamines, and the moiety (diacid of Cb) is selected from linear or branched aliphatic diacids, alicyclic diacids and aromatic diacids;

[0098] XT represents the moiety obtained by polycondensation of a diamine of Cx and terephthalic acid, where x represents the number of carbon atoms in the diamine of Cx, x being between 6 and 36, advantageously between 9 and 18, particularly polyamides of the formula A / 6T, A / 9T, A / 10T or A / 11T, A being as defined above, particularly polyamides PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PABACT / 10T / 6T, PA 11 / BACT / 10T.

[0099] T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane.

[0100] Preferably:

[0101] - The aliphatic polyamide is selected from polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, as well as polyetheramides or polyether esteramides copolymerized. Polyamide (PEBA) (or copolymers of polyamide blocks and polyether blocks), preferably selected from polyamide 11 (PA-11), polyamide 12 (PA-66), polyamide 66 (PA-610), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof, and

[0102] - The semi-aromatic polyamide is a semi-aromatic polyamide that may be modified by a urea unit, particularly a semi-aromatic polyamide of the formula PA MXD6 and PAMXD10 or the formula X / YAr, as described in EP1505099, particularly a semi-aromatic polyamide of the formula A / XT, wherein A is selected from a moiety obtained from at least one amino acid, a moiety obtained from at least one lactam, and at least a moiety corresponding to the formula (diamine of Ca). (diacid of Cb), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18, the moiety (diamine of Ca) is selected from linear or branched aliphatic diamines, alicyclic diamines and alkyl aromatic diamines, and the moiety (diacid of Cb) is selected from linear or branched aliphatic diacids, alicyclic diacids and aromatic diacids;

[0103] XT represents the moiety obtained by polycondensation of a diamine of Cx and terephthalic acid, where x represents the number of carbon atoms in the diamine of Cx, x being between 6 and 36, advantageously between 9 and 18, particularly polyamides of the formula A / 6T, A / 9T, A / 10T or A / 11T, and A being, for example, as defined above, particularly polyamides PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 10T.

[0104] T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane.

[0105] Preferably, the polyamide is a semi-aromatic polyamide selected from PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, and PA 11 / MXDT / 10T.

[0106] Preferably, the polyamide is an aliphatic polyamide PA11 or PA12, with PA11 being more preferred.

[0107] According to an alternative, the polyamide is a polyether amide or polyether ester amide copolymer (PEBA) (or a copolymer of polyamide blocks and polyether blocks). The polyamide blocks of these copolymers may be selected from polyamide 6, polyamide 11, polyamide 6.10, polyamide 6.12, polyamide 10.10, polyamide 10.12, polyamide 10.14, polyamide 12, and combinations thereof. The polyether blocks of these copolymers may be selected from PEG (polyethylene glycol), PPG (polypropylene glycol), PO3G (polytrimethylene glycol), PTMG (polytetramethylene glycol or polytetrahydrofuran), and combinations thereof. Such copolymers may be prepared according to either ATOFINA patent application FR2846332 or UBE INDUSTRIE patent application EP1482011.

[0108] Preferably, the reactive thermoplastic polymer is an amorphous polyamide or a semi-crystalline polyamide, whose absolute value of the melting enthalpy in the component (C1) prior to overmolding is less than 12 J / g matrix resin, preferably less than 8 J / g matrix resin, and more preferably less than 5 J / g matrix resin, calculated according to equation (1).

[0109] Equation (1):

[0110]

[0111] Enthalpy was measured by differential scanning calorimetry (DSC) according to ISO 11357-3 standard 2013, wherein the melting peak and crystallization peak were the first heating peaks at a rate of 20 K / min. Advantageously, the composite obtained with this matrix allows for even better adhesion with the overmolding matrix, particularly resulting in even greater peel strength. It should be understood that the component (C1) is preferably obtained by implementing a matrix resin composition, wherein the at least one polyamide is an amorphous or semi-crystalline polyamide whose absolute value of the melting enthalpy in the component (C1) prior to overmolding is less than 12 J / g of the matrix resin, preferably less than 8 J / g, and most preferably less than 5 J / g.

[0112] The following information allows for understanding how to perform enthalpy of fusion measurements from component (C1). It should be understood that during DSC analysis of component (C1), and particularly during the first heating cycle, crystals initially not present in component (C1) may form, and the formation of these crystals will increase the enthalpy of fusion measured in that same first heating. To determine the actual enthalpy of fusion of component (C1), it is therefore necessary to measure the enthalpy of fusion from the first heating peak (C1). Figure 1 Subtract the area of ​​peak B from the area of ​​the first heating crystallization enthalpy peak. Figure 1 The area of ​​peak A in the sample (if present). It is also agreed that the actual enthalpy of melting of component (C1) is recorded as an absolute value. It is also agreed that the enthalpy of crystallization upon first heating may be zero; if it is zero, then the actual enthalpy of melting of component (C1) is equal to the enthalpy of melting upon first heating.

[0113] The actual enthalpy of fusion thus measured and calculated is then corrected relative to the mass rate of the matrix resin (and any fusible filler of the matrix resin) in the component (C1) and reported to the mass of the matrix resin in the component (C1), so that the above enthalpy is therefore expressed in J / g matrix resin.

[0114] The mass percentage of the matrix resin can be obtained according to ASTM D3171-22 by acid digesting the resin and weighing it before / after digestion.

[0115] Fiber materials

[0116] Preferably, the fibrous material is composed of fibers, particularly mineral, organic, or plant-derived fibers that are typically in the form of strands.

[0117] The fiber is preferably a continuous fiber.

[0118] Among mineral-derived fibers, examples include carbon fiber, glass fiber, basalt fiber, silica fiber, or silicon carbide fiber.

[0119] Advantageously, these are carbon fibers or glass fibers, wherein the number of fibers per strand of the carbon fibers is greater than or equal to 12K (therefore 12,000 filaments / strand), particularly greater than or equal to 24K (24,000 filaments / strand), and the weight of the glass fibers is greater than or equal to 1200 tex, particularly greater than or equal to 2400 tex.

[0120] Among plant-derived fibers, those based on flax, hemp, lignin, bamboo, silk, especially spider silk, or sisal, as well as cellulose fibers, particularly viscose fibers, are particularly noteworthy. These plant-derived fibers can be pure, treated, or coated to promote the adhesion and impregnation of the matrix resin components.

[0121] Among organic-source fibers, organic-source fibers may be mentioned, such as amorphous thermoplastic fibers, whose glass transition temperature Tg is higher than the Tg of the polymer of the matrix resin component (when the polymer of the matrix resin component is amorphous) or higher than the Tf of the polymer of the matrix resin component (when the matrix resin component is semi-crystalline), and whose Tg (in the amorphous case) or Tf (in the semi-crystalline case) is higher than the injection temperature of the overmolding resin component; or semi-crystalline thermoplastic fibers, whose melting temperature Tf is higher than the Tg of the polymer of the matrix resin component (when the matrix resin component is amorphous) or higher than the Tf of the polymer of the matrix resin component, and whose Tg (in the amorphous case) or Tf (in the semi-crystalline case) is higher than the injection temperature of the overmolding resin component; or mixtures of two or more of the aforementioned fibers, preferably mixtures of carbon, glass or silicon carbide fibers, especially carbon fibers.

[0122] Preferably, the fiber is a mineral fiber, particularly a mixture of carbon, glass or silicon carbide fibers, especially carbon fiber.

[0123] Fiber materials can also be fabrics woven or woven from fibers.

[0124] It can also correspond to fibers with holding threads.

[0125] These constituent fibers can be used alone or in combination. Thus, organic fibers can be mixed with mineral fibers impregnated with a thermoplastic polymer, optionally with a chain extender, to form an impregnated fibrous material.

[0126] Organic fiber strands can have several weights. They can also take on several geometries. Fibers can exist as short fibers, which are then used to form felts or nonwovens, which can be in the form of strips, pads, or blocks, or they can exist as continuous fibers, which form 2D fabrics, braids, or unidirectional (UD) fiber strands or nonwovens. The constituent fibers of the fibrous material can also exist as a mixture of reinforcing fibers of these different geometries. Preferably, the fibers are continuous.

[0127] Preferably, the fibrous material is composed of continuous carbon, glass, or silicon carbide fibers or mixtures thereof, particularly carbon fibers. It is used in the form of one strand or several strands.

[0128] In one embodiment, the matrix resin component is distributed within the fibers in a manner as uniform as possible to achieve minimal porosity, in other words, minimal voids between the fibers. In practice, the presence of pores in this type of material can, for example, act as stress concentration points during mechanical tensile stress, and they then form the initiation points for the rupture of the impregnated fiber material and mechanically weaken it. Therefore, the uniform distribution of the matrix resin component improves the mechanical strength and uniformity of the composite material (component (C1)) formed from these impregnated fiber materials.

[0129] The fiber content in component (C1) is preferably between 40 and 65% by volume, more preferably between 40 and 60% by volume, and particularly between 50 and 60% by volume.

[0130] Impregnation rate can be measured by image analysis of the cross-section of the component (C1), particularly using a microscope, camera, or digital camera, by dividing the surface of the component (C1) impregnated by the matrix resin component by the total surface area of ​​the product (the impregnated surface includes the matrix resin and fibers, plus the surface area of ​​the pores). To obtain good quality images, it is preferable to embed the component (C1) cut along its transverse direction in a standard cold-polymerized polishing resin and polish it using a standard method, thereby allowing the sample to be observed at a microscope magnification of at least 6x.

[0131] Advantageously, the porosity of the impregnated fibrous material (component (C1)) is less than 10%, particularly less than 5%, and especially less than 2%.

[0132] It should be noted that zero porosity is difficult to achieve (or measure), and therefore, advantageously, porosity is greater than 0% but less than the aforementioned ratio.

[0133] Porosity corresponds to closed-cell porosity and can be determined by electron microscopy or by the relative difference between the theoretical density and experimental density of the impregnated fiber material, as described in the Embodiments section of this invention, for example.

[0134] The component (C1) can be obtained from fibrous materials by any method known to those skilled in the art, and in particular, for example, by coating in a fluidized bed, impregnating in an aqueous or solvent dispersion of polymer powder, extruding in a polymer melt (or melt route), or spraying dry powder (excluding active electrostatic powdering).

[0135] In a particularly preferred embodiment, the component (C1) of the present invention may be obtained according to the method described in WO2018 / 234436 and, in a particularly preferred embodiment, according to the fluidized bed method described on pages 15 to 21 of WO2018 / 234436.

[0136] Coating molding resin components

[0137] The coating molding resin component according to the present invention comprises at least one polymer selected from polymers used in the matrix resin.

[0138] Preferably, the polymer coating the molding resin is the same as or different from the polymer of the matrix resin. Preferably, the polymer coating the molding resin component and the polymer of the matrix resin component have the same chemical properties (especially functional groups) and the same physical properties.

[0139] Preferably, the coating molding resin component according to the present invention comprises at least one polymer selected from polyamide, polyetheramide, or polyether esteramide copolymer.

[0140] Polyamides are preferably the matrix resins as defined above.

[0141] When the overmolding resin component contains at least one polyamide, it may be the same as or different from the polyamide in the matrix resin component.

[0142] Preferably, the polymer coating the molding resin component and the polymer of the matrix resin component have the same chemical properties (especially functional groups) and the same physical properties.

[0143] Preferably, the polymer coating the molding resin component and the polymer of the matrix resin component are the same.

[0144] In the particularly preferred method:

[0145] - The matrix resin contains an aliphatic polyamide, preferably PA11 or PA12, such as PA11, and the overmolding resin contains PEBA; or

[0146] - The matrix resin contains an aliphatic polyamide, preferably PA11 or PA12, such as PA11, and the overmolding resin contains an aliphatic polyamide, preferably PA11 or PA12, preferably PA11; or

[0147] - The matrix resin contains an aliphatic polyamide, preferably PA11 or PA12, such as PA11, and the overmolding resin contains a semi-aromatic polyamide; or

[0148] - The matrix resin comprises a semi-aromatic polyamide, and the overmolding resin comprises an aliphatic polyamide, preferably PA11 or PA12, such as PA11.

[0149] Optionally, the overmolding resin component includes at least one additive, particularly selected from catalysts, antioxidants, heat stabilizers, UV stabilizers, light stabilizers, lubricants, release agents, fillers, plasticizers, flame retardants, nucleating agents, chain extenders, colorants, conductive agents, thermally conductive agents, or mixtures thereof.

[0150] Advantageously, the additive is selected from heat stabilizers, antioxidants, flame retardants, conductive agents, and thermal conductive agents.

[0151] The surface resin composition may also include liquid crystal polymers or cyclized poly(butylene terephthalate), or mixtures thereof. These compounds, in particular, allow the molten matrix resin to be fluidized for better penetration into the core of the fibrous material.

[0152] The filler may be selected, for example, from carbon fillers, particularly carbon black or carbon nanofillers, preferably from graphene, carbon nanotubes, carbon nanofibers, or mixtures thereof. In a particularly preferred embodiment, the coating molding resin component of the present invention comprises 0.01% to 2% by weight of filler, preferably 0.01% to 0.5% by weight, relative to the total weight of the coating molding resin component.

[0153] The coating molding resin component may also contain fibers, and more preferably short fibers, preferably short glass fibers or short carbon fibers.

[0154] Before the composition is implemented, the fibers are preferably between 2 and 13 mm in length, more preferably between 3 and 8 mm.

[0155] Component (C2) can be in the form of foam, thus allowing for weight reduction. The term "foam" or "polymer foam" refers to a two-phase material containing a continuous phase consisting of a polymer matrix and a continuous or discontinuous gas phase. When the polymer matrix is ​​the only continuous phase of the system, the foam is said to have closed porosity. The gas exists only in discrete form as bubbles. Otherwise, in open-porosity foams, the gas phase and polymer phase are continuous. The foam according to the invention can be prepared by mixing a coated molding resin with an expanding agent (and optionally one or more additives) and then performing a foaming step. The expanding agent can be a chemical or physical reagent, or it can also consist of any type of hollow material or any type of expandable microsphere. For example, but not limited to, physical expanding agents can be nitrogen or carbon dioxide, or hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, or hydrochlorofluorocarbons (saturated or unsaturated) or mixtures thereof. Physical expanding agents can exist in gaseous, liquid, or supercritical form and in this case are converted to the gas phase during the foaming step. This same foaming step can be caused by thermodynamic instabilities of the type of pressure and / or temperature jumps. For polyamides, particularly, the density of the foam is less than or equal to 1000 kg / m³, preferably less than or equal to 800 kg / m³, more preferably less than or equal to 600 kg / m³, more preferably less than or equal to 500 kg / m³, more preferably less than or equal to 400 kg / m³, more particularly preferably less than or equal to 300 kg / m³, and ideally less than or equal to 200 kg / m³. The foam density can be controlled according to techniques known to those skilled in the art and, particularly, by adjusting the parameters of the preparation method. The density, or density measure, is determined according to ISO 1183-1 by immersion in water (23°C).

[0156] Preferably, the thickness of component (C1) is between 0.07 and 50 mm, more preferably between 0.15 and 50 mm, even more preferably between 0.15 and 10 mm, for example between 0.15 and 4 mm, and the thickness of component (C2) is between 0.5 and 50 mm, more preferably between 0.5 and 10 mm, more preferably between 0.5 and 5 mm, and more preferably between 0.15 and 2 mm.

[0157] In a particularly advantageous manner, the overmolded composite structure of the present invention does not contain an adhesive primer between components (C1) and (C2). Therefore, and in a particularly advantageous manner, components (C1) and (C2) in the overmolded composite structure are in direct contact without any intermediate layer. The cohesive force between components (C1) and (C2) is provided by a specific selection of the polyamide of the matrix resin component as defined above.

[0158] The absence of an adhesive primer allows for easier recycling of the overmolded composite structure. Recycling can be carried out, in particular, by grinding the overmolded composite structure to obtain fragments, heating the fragments to their melting point to form a molten mass, and extruding the molten mass in pellet form. Recycling can also be carried out by disassembling both components (C1) and (C2), for example by heating or cooling, and then recycling or reusing components (C1) and (C2) separately.

[0159] The term "adhesion primer" refers to a compound that, when applied to a carrier (in this case, component (C1)) and intended to receive a second carrier (in this case, component (C2)), allows for enhanced bonding between the two carriers and thus creates a chemical and / or physical bond between them, resulting in strong adhesion between the carriers and thus allowing curing and thereby increasing the adhesion between component (C2) and component (C1). Such adhesion primers are, for example, epoxides, combinations of epoxides, ethyl silicate, aromatic or aliphatic polyurethanes and mixtures thereof, such as aromatic or aliphatic polyurethanes, epoxides, or mixtures of aromatic or aliphatic polyurethanes and epoxides.

[0160] Preferably, the overmolded composite structure does not contain an adhesive primer selected from epoxides, combinations of epoxides, ethyl silicate, aromatic or aliphatic polyurethanes and mixtures thereof, such as aromatic or aliphatic polyurethanes, epoxides, mixtures of aromatic or aliphatic polyurethanes and epoxides.

[0161] method

[0162] This application also relates to a method for manufacturing an overmolded composite structure according to the invention, comprising the step of overmolding a component (C2) onto at least a portion of the surface (S) of a component (C1). Overmolding methods are known to those skilled in the art. Thus, the second component (C2) is molded in a mold containing the preformed component (C1). The overmolding resin component is introduced in a molten state.

[0163] Any overmolding technique known to those skilled in the art can be implemented. In a preferred embodiment, the overmolding of the method of the present invention is performed by injection (injecting the overmolding resin component into the mold).

[0164] The component (C1) is manufactured using any technique known to those skilled in the art prior to implementing the method of the present invention. The component (C1) may be given shape prior to the overmolding step.

[0165] In an advantageous manner, the method of the present invention does not involve the steps of assembling components (C1) and (C2) by adhering a primer.

[0166] In a preferred embodiment, the method of the present invention does not require heating the assembly (C1) prior to the overmolding step. Preferably, the mold is heated during the overmolding step to a maximum temperature corresponding to Tg+40°C of the matrix resin composition.

[0167] use

[0168] The present invention also relates to the use of the above-described overmolded composite structure in the manufacture of components, particularly in the fields of machinery, aviation, marine, automotive, oil and gas (especially offshore and gas storage), energy, health and medical, sports and leisure, and electronics.

[0169] The present invention also relates to the use of a matrix resin component, as defined above, for preparing a molded composite structure comprising a first component (C1) and a second component (C2) to improve adhesion between the components (C1) and (C2), wherein the first component (C1) comprises at least one fibrous material and the matrix resin component, and the second component (C2) comprises a molded resin component.

[0170] The present invention also relates to the use of, for example, the matrix resin component as defined above, for preparing a molded composite structure comprising a first component (C1) and a second component (C2) to obtain a peel strength between the components (C1) and the components (C2) of greater than or equal to 50 N / cm, preferably greater than or equal to 70 N / cm, and particularly preferably greater than or equal to 100 N / cm, as measured according to a suitable scheme (90° peel) of ISO 4578:1997, wherein the first component (C1) comprises at least one fibrous material and the matrix resin component, and the second component (C2) comprises a molded resin component.

[0171] The present invention also relates to the use of, for example, the matrix resin component as defined above for preparing a coated molded composite structure comprising a first component (C1) comprising at least one fibrous material and the matrix resin component; and a second component (C2) comprising a coated molding resin component, wherein no primer is required between the components (C1) and the components (C2).

[0172] The invention will be explained in more detail in the following embodiments.

[0173] Example

[0174] Unless otherwise stated, percentages are expressed by weight relative to the total weight of the composition.

[0175] Example 1

[0176] Preparation of component (C1) (also known as complex):

[0177] All composites are unidirectional, meaning the reinforcing fibers are all oriented in the same direction. The fibers used consist of carbon filaments with a unit diameter of 7 μm. As described in WO2018 / 234436, these carbon fibers, initially composed of 24,000 filaments each, were impregnated in a so-called fluidized bed powder method using a powder (reactive or non-reactive) of polyamide 11 (PA11) with the same average particle size D50 = 108 μm. The powder was pre-added with 0.1 wt% Monarch 800 carbon black (Cabot). The resulting pre-impregnated material had an average width of 98 mm and an average thickness of 145 μm, and an average fiber content of 55% by volume + / - 1% as measured by ASTM D3171-22.

[0178] The resulting prepregs are either used alone as component C1 in the impregnation process output, or post-crystallized under vacuum, or finally assembled and consolidated into a unidirectional composite by stacking multiple prepregs in an automated fiber placement (AFP) and then consolidating them under hot pressing. If a reactive resin is used, the consolidation time under the press at a holding temperature (above Tf, here 210°C) allows for adjustment of the molar mass. Here, we hold the consolidation at 210°C for 3 minutes, always at a pressure of 10 bar. The cooling rate of the plate under the press is also varied (from very fast to very slow (5°C / min) for samples quenched by air) to adjust the crystallization rate of the composite sample.

[0179] The samples will be named as follows:

[0180] -T01: Pre-impregnation by fluidized bed impregnation method

[0181] -T02: Pre-impregnated by a fluidized bed impregnation process involving recrystallization under vacuum at 130°C for 3 hours.

[0182] -P31: Pre-impregnated T01, assembled and solidified under a press for 3 minutes, and cooled by air quenching.

[0183] -P32: Pre-impregnated T01, assembled and cured under press for 3 minutes, and slowly cooled at 5°C / min.

[0184] The resulting plate has a final thickness of 1.1 mm on average.

[0185] The composite material, which is integrated into the overmolding mold, is pre-cut to 98 x 98 mm. 2 The sample was dried in the specified format under vacuum at 80°C for 24 hours.

[0186] Before integration into the overmolding mold, a 7 mm wide strip of the composite is covered with a polyimide adhesive film on the edge of the composite to initiate peeling after overmolding.

[0187] Injection polymer and overmolding methods:

[0188] The polymer used for injection molding is BESNO TL grade polyamide 11. A vertical press with dimensions of 100×100×2mm was used. 3 Injection was performed using a mold with a cavity volume and center point injection. PA11 was injected using a barrel temperature of 290°C and a mold temperature of 80°C (approximately 100°C lower than the melting point of the composite (matrix resin) or the polyamide 11 used for injection). The holding pressure for these tests was 60% of the switching pressure, and the holding time was 15 seconds.

[0189] Characterization of the composite prior to encapsulation molding:

[0190] Fiber content measured according to ASTM D3171-22: 55% vol + / -1% vol

[0191] Measurement of the enthalpy of melting of the matrix resin in DSC (ISO 11357-3:2013)

[0192] Determination of molecular weight Mn in GPC of matrix resin

[0193] As described above, the viscosity of the matrix resin was measured.

[0194] Preparation and peel test of the peel sample:

[0195] The obtained molded plate was then cut to extract a size of 98×15mm. 2 The peeled sample was cut in the longitudinal direction of the fiber (so 98 mm corresponds to the length of the sample in the fiber direction).

[0196] Adhesive properties were measured according to the 90° peel method adapted from ISO 4578:1997. The setup used was a pulley system connected to a Criterion C42 force gauge equipped with a suitable force sensor. Tests were conducted at a speed of 50 mm / min with a crosshead displacement of 50 mm. Five different specimens were analyzed for each type of overmolded part.

[0197] result

[0198] - For Examples C001 to C004, the polyamide 11 powder used in the impregnation method to generate component (C1) (also referred to as the composite) is a PA11 reactive powder and exhibits the following characteristics before impregnation: at 240°C and 1800s-1 The melt viscosity at the shear rate is 0.4 Pa·s, Mn = 5400 g / mol (GPC molecular weight), and IP = 2.1. For Example C005, the polyamide 11 powder used in the impregnation method to produce the component (C1) (also referred to as the composite) is a non-reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and 1800 s -1 The melt viscosity at the given shear rate is 0.4 Pa·s, Mn = 6200 g / mol (GPC molecular weight), and IP = 2.1.

[0199] For Example C006, the polyamide 11 powder used in the impregnation method to produce component (C1) (also referred to as the composite) is a non-reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and 1800s -1 The melt viscosity at the given shear rate is 1.3 Pa·s, Mn = 10100 g / mol (GPC molecular weight), and IP = 2.1.

[0200]

[0201] All composite data were measured before preheating the composite.

[0202] The above embodiments demonstrate that, when comparing C001 and C005, and C003 and C006, higher peel strength is achieved when the matrix resin of the composite prior to overmolding is reactive. Similarly, comparative tests of C001 to C003 and C004 show that, in the case of a reactive matrix resin in the composite prior to overmolding, higher peel strength can be achieved if the matrix resin has low viscosity and low molar mass prior to overmolding.

[0203] Example 2

[0204] Preparation of component (C1) (also known as complex):

[0205] The composites are all unidirectional, meaning the reinforcing fibers are all oriented in the same direction. The fibers used consist of carbon filaments with a unit diameter of 7 μm. As described in WO2018 / 234436, these carbon fibers, initially composed of 24,000 filaments each, were impregnated in a so-called fluidized bed powder method using polyamide 11 (PA11) powder with the same average particle size D50 = 108 μm. The powder was pre-added with 0.1% by weight of Monarch 800 carbon black (Cabot).

[0206] The obtained prepreg (or component C1) has an average width of 98 mm and an average thickness of 145 μm, and an average fiber content of 55% by volume + / - 1%, as measured by ASTM D3171-22.

[0207] Overmolding method

[0208] The obtained component (C1) is cut to obtain a sample with the following dimensions (L×W×H): 125×25×1.5mm.

[0209] The specimen is placed in a mold, allowing the specimen to be held on one side and the polymer overmolding component injected on the other side, so as to create a 25x25 mm contact area between the composite substrate and the overmolded surface component. Representative illustrations of these specimens are shown in [illustration missing]. Figure 2 In the middle (black represents the composite (C1), and white represents the overmolded component (C2)).

[0210] Storage and analysis conditions

[0211] Upon removal from the overmolding process, the overmolded specimens were conditioned in a sealed bag at 23°C for at least 240 h. After opening the bag and until testing, the specimens were placed in a desiccator at room temperature.

[0212] Tensile tests on the offset support were conducted according to conditions close to NF EN 1465 (2009) standard, details of which are as follows:

[0213] ○ Initial distance between jaws: 115mm

[0214] ○ Test speed: 1.3mm / min

[0215] ○ Test temperature: 23°C + / -2°C

[0216] ○ Relative humidity: 50% + / -10%

[0217] Once the composite / polymer interface breaks, the breaking force is measured.

[0218] The device used in the test was a ZWICK 1455 force gauge equipped with a 20 kN sensor (cell).

[0219] Prior to the overmolding step, the area of ​​the composite (C1) that will then come into contact with the overmolding component (C2) can be preheated.

[0220] Overmolding is performed at a temperature of 260°C.

[0221] The matrix implemented in component (C1) is as follows:

[0222] S1: The PA11 powder used to produce component (C1) in the impregnation method is a reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and at 1800s -1 The melt viscosity at the given shear rate is 0.7 Pa·s, Mn = 7500 g / mol (GPC molecular weight), and IP = 2.3.

[0223] S2: The PA11 powder used to produce component (C1) in the impregnation method is a non-reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and at 1800s -1 The melt viscosity at the given shear rate is 0.4 Pa·s, Mn = 6200 g / mol (GPC molecular weight), and IP = 2.1.

[0224] S3: The PA11 powder used to produce component (C1) in the impregnation method is a reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and at 1800s -1 The melt viscosity at the given shear rate is 0.4 Pa·s, Mn = 5400 g / mol (GPC molecular weight), and IP = 2.1.

[0225] S4 (Comparison): The PA11 powder used to produce component (C1) in the impregnation method is a non-reactive PA11 powder and exhibits the following characteristics before impregnation: at 240°C and at 1800s -1 The melt viscosity at the given shear rate is 205 Pa·s, Mn = 39500 g / mol (GPC molecular weight), and IP = 2.1.

[0226] The results are listed in the table below:

[0227] Table 2

[0228]

[0229] Table 3:

[0230]

[0231] Tests show that using the matrix resin according to the invention in component C1 for preparing the overmolded composite allows for good adhesion without preheating component C1 prior to the overmolding step. Tests also show that by preheating component C1, adhesion is improved relative to overmolded composites using matrix resins different from those of the present invention.

[0232] The comparative test using S2 must be compared with the test using S3 (same viscosity). This comparison shows that the combination of molar mass and reactivity characteristics allows for improved adhesion between the component (C1) and the overmolded component (C2).

Claims

1. Overmoulded composite structure comprising: i) a first component (C1) comprising at least one fibrous material and a matrix resin composition comprising at least one reactive thermoplastic polymer and possibly chain extender and / or chain limiter and / or catalyst and / or one or more additives, the thermoplastic polymer having a number average molecular weight Mn between 3,000 and 35,000 g / mol, preferably between 5,000 and 20,000 g / mol, preferably between 5,000 and 15,000 g / mol, more preferably between 5,000 and 10,000 g / mol; and ii) a second component (C2) comprising an overmoulding resin composition, the first component (C1) comprising at least one surface (S) and the component (C2) adhering to the component (C1) on at least a portion of the surface (S).

2. Overmoulded composite structure according to claim 1, wherein the at least one reactive thermoplastic polymer is a polyamide, a polycarbonate or a polymethacrylate, preferably a polyamide, and optionally comprises epoxy-type groups, preferably the reactive thermoplastic polymer is a polyamide.

3. Overmoulded composite structure according to claim 1 or 2, wherein the at least one reactive thermoplastic polymer is selected from: - aliphatic polyamides selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010, and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and polyetheramides or polyether ester amide copolymers (PEBA) (or copolymers of polyamide blocks and polyether blocks), or - aromatic polyamides selected from polyamide 6T (PA-6T), polyamide 6I (PA-6I), polyamide 6T / 6I (PA-6T / 6I), polyamide 6 / 6T (PA-6 / 6T), polyamide 6 / 6I (PA-6 / 6I), polyamide 6 / 6T / 6I (PA-6 / 6T / 6I), polyamide 6 / 6 / 6T / 6I (PA-6 / 6 / 6T / 6I), polyamide 6 / 6 / 6T (PA-6 / 6 / 6T), polyamide 6 / 6 / 6I (PA-6 / 6 / 6I), polyamide 6 / 6 / 6T / 6I / 6 (PA-6 / 6 / 6T / 6I / 6), polyamide 6 / 6 / 6T / 6I / 6T (PA-6 / 6 / 6T / 6I / 6T), polyamide 6 / 6 / 6T / 6I / 6I (PA-6 / 6 / 6T / 6I / 6I), polyamide 6 / 6 / 6T / 6I / 6 / 6T (PA-6 / 6 / 6T / 6I / 6 / 6T), polyamide 6 / 6 / 6T / 6I / 6 / 6I (PA-6 / 6 / 6T / 6I / 6 / 6I), polyamide 6 / 6 / 6T / 6I / 6 / 6T / 6I (PA-6 / 6 / 6T / 6I / 6 / 6T / 6I), polyamide 6 / 6 / 6T / 6I / 6 / 6T / 6I / 6 (PA-6 / 6 / 6T / 6I / 6 / 6T / 6I / 6), or mixtures thereof or copolyamides thereof, and - semi-aromatic polyamides, which are semi-aromatic polyamides possibly modified with urea units, in particular PA MXD6 and PA MXD10 or semi-aromatic polyamides of formula A / XT, in which A is chosen from a motif obtained from at least one amino acid, a motif obtained from at least one lactam and at least one motif corresponding to a diamine of formula (Ca and a diacid of formula (Cb), in which a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, the motif (diamine of formula (Ca) being chosen from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines, and the motif (diacid of formula (Cb) being chosen from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; X.T represents a motif obtained from the polycondensation of a diamine of formula Cx and terephthalic acid, in which x represents the number of carbon atoms of the diamine of formula Cx, x being between 6 and 36, advantageously between 9 and 18, in particular polyamides of formula A / 6T, A / 9T, A / 10T or A / 11T, A being for example as defined above, in particular polyamides PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 10T; T corresponding to terephthalic acid, MXD corresponding to m-xylylenediamine, MPMD corresponding to methylpentamethylene diamine and BAC corresponding to 1,3-bis(aminomethyl)cyclohexane.

4. The overmoulded composite structure according to any one of claims 1 to 3, wherein the at least one reactive thermoplastic polymer is selected from: - aliphatic polyamides selected from polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010, and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and polyether amide or polyether ester amide copolymer (PEBA) (or block copolymer with polyamide blocks and polyether blocks), or - semi-aromatic polyamides possibly modified with urea units, in particular PA MXD6 and PA MXD10 or semi-aromatic polyamides of formula A / X T, in which A is chosen from a motif obtained from at least one amino acid, a motif obtained from at least one lactam and at least one motif corresponding to a diamine of formula (Ca and a diacid of formula (Cb), in which a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, the diamine of formula (Ca being chosen from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines and the diacid of formula (Cb) being chosen from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; X.T represents a motif obtained from the polycondensation of a diamine of Cx and terephthalic acid, in which x represents the number of carbon atoms in the diamine of Cx, x being between 6 and 36, advantageously between 9 and 18, in particular polyamides of formula A / 6T, A / 9T, A / 10T or A / 11T, A being for example as defined above, in particular polyamides PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA PMPDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA PMPDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 10T, T corresponding to terephthalic acid, MXD corresponding to m-xylylenediamine, MPMD corresponding to methylpentamethylene diamine and BAC corresponding to 1,3-bis(aminomethyl)cyclohexane.

5. The overmoulded composite structure according to any one of claims 1 to 4, wherein the reactive thermoplastic polymer is a semi-aromatic polyamide selected from PA PMPDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA PMPDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T.

6. The overmoulded composite structure according to any one of claims 1 to 4, wherein the reactive thermoplastic polymer is PA11 or PA12, preferably PA11.

7. The overmoulded composite structure according to any one of claims 1 to 6, wherein the overmoulding resin component is the same or different from the matrix resin, preferably it comprises an aliphatic or semi-aromatic polyamide polymer as defined in any one of claims 3 to 6.

8. The overmoulded composite structure according to any one of claims 1 to 7, wherein the fibrous material comprises continuous fibres selected from: - mineral origin fibers, such as carbon, glass, silicon carbide, basalt, silica fibers; - plant origin fibers, in particular fibers based on flax, hemp, lignin, bamboo, silk, in particular spider silk, or sisal, cellulose fibers, in particular viscose fibers; - organic origin fibers, such as amorphous thermoplastic fibers having a glass transition temperature Tg higher than the Tg of the polymer of the matrix resin component when the polymer of the matrix resin component is amorphous or higher than the Tf of the polymer of the matrix resin component when the polymer of the matrix resin component is semi-crystalline, and having a Tg (in the case of amorphous) or Tf (in the case of semi-crystalline) higher than the injection temperature of the overmolding resin component, or semi-crystalline thermoplastic fibers having a melting temperature Tf higher than the Tg of the polymer of the matrix resin component when the polymer of the matrix resin component is amorphous or higher than the Tf of the polymer of the matrix resin component, and having a Tg (in the case of amorphous) or Tf (in the case of semi-crystalline) higher than the injection temperature of the overmolding resin component, or a mixture of two or more of said fibers, preferably a mixture of carbon, glass or silicon carbide fibers, in particular carbon fibers, or a mixture thereof.

9. The overmolded composite structure of any one of claims 1 to 8, wherein The overmolded composite structure does not comprise an adhesion primer between the components C1 and C2.

10. The overmolded composite structure according to any one of claims 1 to 9, wherein the matrix resin component does not comprise a filler or comprises less than 2 wt% of a filler, preferably 0.01 to 0.5 wt% of a filler, relative to the weight of the matrix resin component.

11. Overmolded composite structure according to any one of claims 1 to 10, wherein the reactive thermoplastic polymer has a melt viscosity measured in capillary rheology between 0.05 and 1000 Pa.s, preferably between 0.1 and 1000 Pa.s, preferably between 0.3 and 1000 Pa.s, preferably between 0.3 and 500 Pa.s, more preferably between 0.3 and 250 Pa.s, for example between 0.3 and 100 Pa.s, even more preferably between 0.3 and 50 Pa.s, more preferably between 0.3 and 25 Pa.s, even more preferably between 0.3 and 10 Pa.s, preferably between 0.3 and 5 Pa.s, at a shear rate of 1800 s -1 at Tf + 50°C, Tf being the melting temperature of the at least one polyamide.

12. The overmolded composite structure according to any one of claims 1 to 11, wherein the reactive thermoplastic polymer is an amorphous polyamide or a semi-crystalline polyamide, which exhibits an absolute value of the enthalpy of fusion in component (C1) calculated according to equation (1) of less than 12 J / g matrix resin, preferably less than 8 J / g matrix resin, preferably less than 5 J / g matrix resin, before overmolding. Equation (1): The measurement of the enthalpy is carried out by differential scanning calorimetry (DSC) according to the ISO 11357-3 standard of 2013, with the melting and crystallization peaks being the first heating peak at a rate of 20 K / min.

13. The overmolded composite structure according to any one of claims 1 to 12, wherein: - the matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises PEBA; or - the matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11; or - the matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmolding resin comprises a semi-aromatic polyamide; or - the matrix resin comprises a semi-aromatic polyamide, and the overmolding resin comprises an aliphatic polyamide, preferably PA11 or PA12, preferably PA11.

14. Process for manufacturing an overmoulded composite structure according to any one of claims 1 to 13, comprising the step of overmoulding said assembly C2 on at least a portion of the surface S of said assembly C1.

15. Process according to claim 14, wherein the overmoulding step is an injection overmoulding step.

16. Use of an overmoulded composite structure according to any one of claims 1 to 11 for manufacturing parts, in particular parts in the fields of machinery, aeronautics, marine, automotive, oil and gas (in particular offshore, gas storage), energy, health and medical, sports and leisure, and electronics.

17. Use of a matrix resin composition, for example as defined in claims 1 to 6 and 10 to 13, for preparing an overmoulded composite structure comprising a first assembly (C1) comprising at least one fibrous material and said matrix resin composition, and a second assembly (C2) comprising an overmoulding resin composition, to achieve a peel strength measured according to the modified protocol of the ISO 4578:1997 standard (90° peel) of greater than or equal to 50 N / cm, preferably greater than or equal to 70 N / cm, and particularly preferably greater than or equal to 100 N / cm, between assembly (C1) and assembly (C2).

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