Overmolded composite material structure

Abstract

The present invention relates to an overmolded composite material structure, i) a first component (C1) comprising at least one fibrous material and a matrix resin composition, wherein the matrix resin composition comprises at least one polyamide, and the at least one polyamide has a number average molecular weight Mn between 3,000 g / mol and 35,000 g / mol, preferably between 5,000 g / mol and 20,000 g / mol, preferably between 5,000 g / mol and 15,000 g / mol, preferably between 5,000 g / mol and 10,000 g / mol, and a shear rate of 1800 s -1 The melt viscosity measured by capillary rheology at Tf + 50°C (where Tf is the melting temperature of at least one polyamide) is between 0.05 Pa·s and 1000 Pa·s, preferably between 0.1 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 500 Pa·s, more preferably between 0.3 Pa·s and 250 Pa·s, for example between 0.3 Pa·s and 100 Pa·s, and even more preferably between 0.3 Pa·s and 100 Pa·s. The present invention relates to an overmolded composite material structure comprising: a first component (C1) having a pressure between s and 50 Pa·s, more preferably between 0.3 Pa·s and 25 Pa·s, even more preferably between 0.3 Pa·s and 10 Pa·s, and preferably between 0.3 Pa·s and 5 Pa·s; and a second component (C2) comprising an overmolded resin composition, wherein the first component C1 has at least one surface S, and the component C2 is bonded to the component C1 on at least a portion of the surface S.

Description

[Technical Field]

[0001] Field of Invention The present invention relates to an overmolded structure comprising a composite material and an overmolded thermoplastic polymer component. [Background technology]

[0002] Technical background Composite materials are being increasingly developed in various fields such as automobiles, aerospace, and sporting goods. Hybrid structures (composite material / metal, composite material / polymer, or metal / polymer, etc.) are also being developed and are seen as interesting alternatives that not only lighten and strengthen structures but also provide multiple functions to manufactured parts. In particular, there is a desire to reduce the weight of a part and lower manufacturing costs by replacing metal parts in specific components. Such composite materials are particularly used in the manufacture of overmolded composite material structures in which components are overmolded onto at least a portion of the surface of the composite material.

[0003] Therefore, many companies in the automotive and aerospace sectors have developed methods for manufacturing improved parts.

[0004] For example, localized reinforcements based on composite materials (carbon fiber + thermoplastic polymer) are placed in injection molding dies for automotive parts to locally and intelligently reinforce injection molded parts (e.g., car doors). In this way, the parts are lighter and reinforced in the direction of preferred stress.

[0005] In addition to these application areas, other companies in cutting-edge technology and high-performance fields have also been trying to utilize these new conversion technologies and adapt them to their own needs.

[0006] Thus, in recent years, numerous developments have taken place in the fields of sports, leisure, and electronics. For example, many manufacturers of running shoes or athletic shoes, as well as bicycles and other competitive or leisure sports equipment, have begun incorporating composite material reinforcements into their shoes. These composite materials enable products to offer a variety of improved performance characteristics, such as greater durability, higher performance (especially energy recovery), and lighter weight.

[0007] These composite materials generally exist in the form of pre-fabricated plates manufactured by conventional methods, typically based on carbon fibers impregnated with thermosetting resins (epoxy), but rarely based on carbon fibers impregnated with thermoplastic resins (acrylic, PC, PP). These composite reinforcements can be incorporated into the final product by different methods, particularly bonding to existing supports. This bonding is essential, ensuring a strong bond between the composite component and the overmolded polymer / elastomer, which generally do not share the same chemical properties. It also allows the composite material to be held in place for subsequent stages of finished product manufacturing. Without this bonding force, the composite material and overmolded product would have limited performance over time and would fail to meet certain essential performance criteria (dimensions and position in the finished product, finish appearance, optical quality, thermal or electrical conductivity / insulation, mechanical load transfer from the overmolded product to the composite, and vice versa, premature interfacial failure, etc.) as soon as they leave the production line.

[0008] The bonding solution is generally based on a reactive thermosetting resin (cold or hot) and / or solvent system, chosen to best suit the components being assembled. Therefore, if two components of an overmolded composite have different chemical properties, they will not be perfectly compatible with each other. Furthermore, depolymerization is impossible during the disassembly and recycling phases that may occur at the end of the product's lifecycle.

[0009] To overcome these inconveniences, alternative solutions have been proposed: - The surface condition of the composite material is refined to make it rougher / more textured. Therefore, certain contact surfaces between the composite material and the adhesive become larger, and thus potentially result in better quality. However, chemical / physical incompatibility remains, limiting the performance and / or the period during which it can be used while maintaining performance. - Use thermoplastic adhesives instead of thermosetting adhesives. However, the application of these adhesives is often more complex, and in most cases, they only fit one of the two components being assembled. - A surface treatment to functionalize one or both surfaces and improve their compatibility. However, this process, which generally consists of plasma treatment (cold or hot), is costly and has a short lifespan (at most a few hours).

[0010] Overmolded composite material structures that do not require the use of adhesives are known from US2012108122. However, because the composite material is heated to near its melting point before the overmolding process, the degree of curing, which affects the physical properties of the composite material, particularly the mechanical performance of the final product, may be compromised.

[0011] Therefore, there is a real need to provide a composite material that is compatible with the overmolded polymer layer and eliminates the need for additional adhesive primers between the composite material and the overmolded components. There is also a real need to provide a composite material that is compatible with the overmolded polymer layer, enables good adhesion between the composite material and the overmolded layer, and in particular enables the acquisition of a peel strength of more than 50 N / cm, preferably 70 N / cm or more, and especially preferably 100 N / cm or more. [Overview of the Initiative]

[0012] Summary of the Invention The present invention mainly relates to an overmolded composite material structure, i) A first component (C1) comprising at least one fibrous material and a matrix resin composition, wherein the matrix resin composition comprises at least one polyamide, and the at least one polyamide has a number average molecular weight Mn between 3,000 g / mol and 35,000 g / mol, preferably between 5,000 g / mol and 20,000 g / mol, preferably between 5,000 g / mol and 15,000 g / mol, more preferably between 5,000 g / mol and 10,000 g / mol; and a shear rate of 1800 s -1 The first component (C1), whose melt viscosity, as measured by capillary rheology, is between 0.05 Pa·s and 1000 Pa·s, preferably between 0.1 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 500 Pa·s, more preferably between 0.3 Pa·s and 250 Pa·s, for example between 0.3 Pa·s and 100 Pa·s, even more preferably between 0.3 Pa·s and 50 Pa·s, even more preferably between 0.3 Pa·s and 25 Pa·s, even more preferably between 0.3 Pa·s and 10 Pa·s, preferably between 0.3 Pa·s and 5 Pa·s; and ii) A second component (C2) comprising an overmolding resin composition. Includes, The present invention relates to an overmolded composite material structure in which the first component C1 includes at least one surface S, and the component C2 is bonded to the component C1 on at least a portion of the surface S.

[0013] Preferably, the polyamide is an aliphatic, alicyclic, or semi-aromatic polyamide: - Aliphatic polyamides are 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 polyetheramide or polyether ester amide copolymer (PEBA) (or copolymer of polyamide block and polyether block), or - Semi-aromatic polyamides may be semi-aromatic polyamides modified by urea units, particularly PA MXD6 and PA MXD10, or of the formula A / XT [wherein A is selected from a constituent unit derived from at least one amino acid, a constituent unit derived from at least one lactam, and at least one constituent unit corresponding to the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, and the constituent unit (Ca diamine) is a linear or branched aliphatic diamine, an alicyclic diamine, and an alkyl aromatic A semi-aromatic polyamide of formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically polyamide 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, where T corresponds to terephthalic acid, MXD to m-xylylenediamine, MPMD to methylpentamethylenediamine, and BAC to 1,3-bis(aminomethyl)cyclohexane.

[0014] Preferably, at least one polyamide is - 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 aliphatic polyamides selected from polyetheramide or polyether ester amide copolymer (PEBA) (or copolymer of polyamide block and polyether block), or - Semi-aromatic polyamides that may be modified by urea units, particularly PA MXD6 and PA MXD10, or of formula A / XT [wherein A is selected from a constituent unit derived from at least one amino acid, a constituent unit derived from at least one lactam, and at least one constituent unit corresponding to the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, and the constituent unit (Ca diamine) is a linear or branched aliphatic diamine, an alicyclic diamine, and an alkyl aromatic A semi-aromatic polyamide of formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically polyamide 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 corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane, semi-aromatic polyamides. It will be selected from among the following.

[0015] 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, PA 11 / MXDT / 10T.

[0016] Preferably, the polyamide is PA11 or PA12, preferably PA11.

[0017] Preferably, at least one polyamide is an amorphous or semi-crystalline polyamide in which the absolute value of the melting enthalpy in the component (C1) before overmolding is less than 12 J per gram of the matrix resin, preferably less than 8 J per gram of the matrix resin, preferably less than 5 J per gram of the matrix resin, calculated according to formula (1). Formula (1): TIFF2026511032000001.tif14170

[0018] The enthalpy measurement is carried out by differential scanning calorimetry (DSC) according to ISO11357-3 in 2013, and the melting peak and crystallization peak are the first heating peaks at a rate of 20 K / min.

[0019] Preferably, the overmold resin composition contains at least one polymer selected from polyamides that are the same as or different from the polyamide of the surface resin composition, or polyetherimide or polyether ester amide copolymer.

[0020] Preferably, - The matrix resin contains an aliphatic polyamide, preferably PA11 or PA12, preferably PA11, and the overmold resin contains 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.

[0021] Preferably, the fibrous material is - Mineral-derived fibers such as carbon fiber, glass fiber, silicon carbide fiber, basalt fiber, and silica fiber; - Plant-derived fibers, especially those based on flax, hemp, lignin, bamboo, silk (especially spider silk), or sisal, and cellulose fibers (especially viscose); - Organic-derived fibers, for example, amorphous thermoplastic fibers, in which the glass transition temperature Tg is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition if the polymer is semicrystalline, and the Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition; or semicrystalline thermoplastic fibers, in which the melting temperature Tf is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition, and the Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition. - Or, a mixture of two or more of the aforementioned fibers, preferably a mixture of carbon fibers, glass fibers, or silicon carbide fibers, particularly carbon fibers. It includes continuous fibers selected from among them.

[0022] Preferably, the overmolded composite material structure of the present invention does not contain an adhesive primer between the constituent elements C1 and C2.

[0023] Preferably, the matrix resin composition contains no filler or contains less than 2% by weight of filler relative to the weight of the matrix resin composition, and preferably contains 0.02 to 0.1% by weight of filler.

[0024] The present invention also relates to a method for manufacturing an overmolded composite material structure according to the present invention, comprising the step of overmolding a component C2 onto at least a portion of the surface S of a component C1.

[0025] Preferably, the overmolding process is an injection overmolding process.

[0026] The present invention also relates to the use of overmolded composite material structures according to the present invention for the manufacture of components in the fields of machinery, aviation, ships, automobiles, oil and gas (particularly offshore and gas storage), energy, health and medicine, sports and leisure, and electronics.

[0027] The present invention also relates to the use of a matrix resin composition as defined according to the present invention for the preparation of an overmolded composite material structure comprising a first component C1 comprising at least one fibrous material and the matrix resin composition, and a second component C2 comprising an overmolding resin composition, wherein a peel strength of 50 N / cm or more, preferably 70 N / cm or more, and particularly preferably 100 N / cm or more is obtained between component C1 and component C2, as measured according to a suitable protocol of ISO 4578:1997 (90° peel). [Brief explanation of the drawing]

[0028] [Figure 1]Figure 1 is a DSC thermogram of component C1 according to the present invention, obtained using a matrix resin containing a semi-aromatic polyamide. This graph corresponds to the first heating of the DSC analysis program and shows the region below the first heating peak corresponding to the first heating crystallization peak (A) and the region below the first heating peak corresponding to the first heating melting peak (B). Enthalpy measurements were performed by differential scanning calorimetry (DSC) according to ISO 11357-3 2013, and the melting and crystallization peaks are the first heating peaks at a rate of 20 K / min. [Figure 2] Figure 2 is a representative diagram of the test specimen prepared in Example 2. [Modes for carrying out the invention]

[0029] Detailed explanation The present invention will be described in more detail and in a non-limiting manner in the following description.

[0030] Unless otherwise specified, all percentages are based on mass.

[0031] In this text, the quantities given for specific species may apply to that species according to all definitions (as mentioned in the text), including more restrictive definitions.

[0032] In this specification, "fibrous material" means an aggregate of a single reinforcing fiber.

[0033] Thermoplastics or thermoplastic polymers are generally solid at room temperature, can be semi-crystalline or amorphous, soften as the temperature rises, especially after exceeding the glass transition temperature (Tg), flow at higher temperatures if amorphous, or, if semi-crystalline, exhibit clear melting above the so-called melting temperature (Tf), and become solid again when the temperature drops below its crystallization temperature (for semi-crystalline materials) and below its glass transition temperature (for amorphous materials).

[0034] Tg and Tf are determined by differential scanning calorimetry (DSC) in accordance with ISO 11357-2:2013 and 11357-3:2013, respectively.

[0035] Overmolded composite material structure The present invention mainly relates to an overmolded composite material structure, i) A first component (C1) comprising at least one fibrous material and a matrix resin composition, wherein the matrix resin composition comprises at least one polyamide, and the at least one polyamide has a number average molecular weight Mn between 3,000 g / mol and 35,000 g / mol, preferably between 5,000 g / mol and 20,000 g / mol, preferably between 5,000 g / mol and 15,000 g / mol, preferably between 5,000 g / mol and 10,000 g / mol, and a shear rate of 1800 s -1 The first component (C1), whose melt viscosity, as measured by capillary rheology, is between 0.05 Pa·s and 1000 Pa·s, preferably between 0.1 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 500 Pa·s, more preferably between 0.3 Pa·s and 250 Pa·s, for example between 0.3 Pa·s and 100 Pa·s, even more preferably between 0.3 Pa·s and 50 Pa·s, even more preferably between 0.3 Pa·s and 25 Pa·s, even more preferably between 0.3 Pa·s and 10 Pa·s, preferably between 0.3 Pa·s and 5 Pa·s; and ii) A second component (C2) comprising an overmolding resin composition. Includes, The present invention relates to an overmolded composite material structure in which the first component (C1) includes at least one surface S, and the component (C2) is bonded to the component (C1) on at least a portion of the surface (S).

[0036] It is important to understand that the first component (C1) can be any 2D or 3D shape, particularly a parallelepiped shape, or a more complex 2D or 3D shape, and therefore can include multiple surfaces (S). Component (C2) is bonded to component (C1) on at least one of its surfaces (S). The present invention also includes cases where component (C2) is bonded to component (C1) on multiple different surfaces (S), and component (C2) can be identical or different depending on the surfaces (S).

[0037] In a particularly advantageous embodiment, the inventors have shown that by a specific selection of the matrix resin composition, good bonding strength, particularly good adhesion (or "bonding strength"), between components (C1) and (C2) can be obtained without the need for the use of an adhesive primer between components (C1) and (C2). In a particularly advantageous embodiment, the inventors have shown that by a specific selection of the matrix resin composition, good adhesion between components (C1) and (C2) can be obtained, characterized in that the peel strength measured according to a suitable protocol of ISO 4578:1997 (90° peel) is 50 N / cm or more, preferably 70 N / cm or more, and particularly preferably 100 N / cm or more.

[0038] Overmolding consists of molding a product (here, a component (C1)). It is important to understand that an overmolded composite material structure is different from the association of two impregnated fiber materials. Unlike impregnated fiber materials, an overmolded resin composition cannot contain continuous fibers. In fact, the presence of continuous fibers would render it unusable in the overmolding process, for example, the injection overmolding process.

[0039] Overmolding involves molding a second component (C2) within a mold containing a pre-made component (C1), wherein the second component (C2) is introduced at a temperature higher than the glass transition temperature of the component (C2) if the component (C2) contains an amorphous polymer, or at a temperature higher than the melting temperature of the component (C2) if the component (C2) contains a semicrystalline polymer.

[0040] Matrix resin composition At least one polyamide in the matrix resin has a number-average molecular weight (Mn) between 3,000 g / mol and 35,000 g / mol, preferably between 5,000 g / mol and 20,000 g / mol, preferably between 5,000 g / mol and 15,000 g / mol, and more preferably between 5,000 g / mol and 10,000 g / mol, and a shear rate of 1800 s. -1 The melt viscosity measured by capillary rheology is between 0.05 Pa·s and 1000 Pa·s, preferably between 0.1 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 500 Pa·s, more preferably between 0.3 Pa·s and 250 Pa·s, for example between 0.3 Pa·s and 100 Pa·s, even more preferably between 0.3 Pa·s and 50 Pa·s, even more preferably between 0.3 Pa·s and 25 Pa·s, even more preferably between 0.3 Pa·s and 10 Pa·s, preferably between 0.3 Pa·s and 5 Pa·s.

[0041] The number-average molecular weight (Mn) and weight-average molecular weight (Mw) are measured by size exclusion chromatography according to ISO 16014-1:2012, 16014-2:2012, and 16014-3:2012, under the following conditions: Equipment:Waters Alliance2695 Equipment Solvent: Hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate Flow rate: 1ml / min Column temperature: 40°C. Two in-line columns: 1000 Å PFG and 100 Å PFG (PPS) Sample concentration: 1 g / L (dissolved for 24 hours at room temperature) Sample filtration using a syringe equipped with an ACRODISC PTFE filter with a diameter of 25 mm and a porosity of 0.2 μm Injection volume: 100 μl Refractive index detection at 40 °C along with UV detection at 228 nm Calibration according to PMMA standards of 1,900,000 - 402 g / mol. Calibration curve modeled by a fifth-order polynomial

[0042] The melt viscosity is measured by capillary rheology using a Gottfert Rheotester 2000 apparatus. The measurement temperature (T) follows the inequality Tf < T ≤ Tf + 70 °C. The measurement is carried out according to ISO11443:2014. 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. The melt viscosity is preferably measured at Tf + 50 °C, where Tf is the melting temperature of at least one polyamide

[0043] Preferably, in the matrix resin composition of the present invention, at least one polyamide is an amorphous or semi-crystalline polyamide in which the absolute value of the melting enthalpy in the component (C1) before overmolding is less than 12 J per gram of matrix resin, preferably less than 8 J, preferably less than 5 J, calculated according to formula (1) Formula (1): TIFF2026511032000002.tif14170

[0044] Enthalpy measurements were performed by differential scanning calorimetry (DSC) in accordance with ISO 11357-3 2013, and the melting and crystallization peaks are the first heating peaks at a rate of 20 K / min. In advantageous embodiments, composite materials obtained using such matrices can obtain even better adhesion with the overmolded matrix, and in particular, even greater peel strength. Therefore, it should be understood that the component (C1) is preferably obtained by mounting a matrix resin composition in which at least one polyamide is an amorphous or semi-crystalline polyamide in which the absolute value of the melting enthalpy of the component (C1) before overmolding is less than 12 J, preferably less than 8 J, and preferably less than 5 J per g of matrix resin.

[0045] The following information helps to understand how the enthalpy of melting is measured from component (C1). During the DSC analysis of component (C1), particularly during the first heating cycle, crystals that were not initially present in component (C1) may form during the first heating cycle. It is important to understand that the formation of these crystals, which were not initially present in component (C1), will increase the enthalpy of melting measured in this same first heating cycle. Therefore, to determine the actual enthalpy of melting of component (C1), it is necessary to subtract the area of ​​the first heating crystallization enthalpy peak (peak A in Figure 1), if present, from the area of ​​the first heating enthalpy of melting peak (peak B in Figure 1). It is also agreed that this actual enthalpy of melting of component (C1) is expressed as an absolute value. It is also agreed that the first heating crystallization enthalpy may be zero, in which case the actual enthalpy of melting of component (C1) is equal to the first heating enthalpy of melting.

[0046] The actual enthalpy of melt measured and calculated in this manner is corrected for the mass fraction of the matrix resin (and any fusible fillers in the matrix resin) in the component (C1) and reported relative to the mass of the matrix resin in the component (C1). Therefore, the above enthalpy is expressed in J / g units of the matrix resin.

[0047] The mass fraction of the matrix resin can be obtained by acid-degrading the resin according to ASTM D3171-22 and measuring the weight before / after degradation.

[0048] Amorphous polyamides do not contain crystals, and therefore, by definition, do not exhibit enthalpy of melting or enthalpy of crystallization.

[0049] The polyamide in the matrix resin composition is selected from homopolymers and copolymers of the aliphatic, alicyclic polyamide (PA), or semi-aromatic polyamide (PA) family (also known as polyphthalamide (PPA)), or mixtures thereof.

[0050] Polyamides can be thermally stabilized. Thermal stabilizers are especially necessary for polyamides that decompose easily at a temperature of Tg + 220°C.

[0051] The nomenclature used to define polyamides is described in particular on page 3 (Tables 1 and 2) of ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation" and is well known to those skilled in the art.

[0052] Polyamides may be homopolyamides, copolyamides, or mixtures thereof.

[0053] Semi-aromatic polyamides are semi-aromatic polyamides optionally modified with urea units, particularly PA MXD6 and PA MXD10, or semi-aromatic polyamides of formula X / YAr as described in EP1505099, particularly formula A / XT [wherein A is selected from a constituent unit derived from at least one amino acid, a constituent unit derived from at least one lactam, and at least one constituent unit corresponding to the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, where the constituent unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the constituent unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; XT is a semi-aromatic polyamide of the formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically the 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.

[0054] T corresponds to terephthalic acid, MXD to m-xylylenediamine, MPMD to methylpentamethylenediamine, and BAC to 1,3-bis(aminomethyl)cyclohexane.

[0055] Aliphatic and alicyclic polyamides are repeating structural units selected from structural units obtained from the polycondensation of at least one amino acid and structural units obtained from the polycondensation of at least one lactam (in the case of aliphatic polyamides), or At least one diamine, wherein the diamine is selected from linear (or branched) aliphatic diamines and alicyclic diamines. At least one carboxylic acid diacid, wherein the diacid is selected from aliphatic diacids and alicyclic diacids, and The repeating structural units are selected from the repeating structural units XY obtained from the polycondensation of (for both aliphatic polyamides and alicyclic polyamides, the diamine and the diacid contain 4 to 36 carbon atoms, preferably 6 to 18 carbon atoms).

[0056] It is clear that alicyclic polyamides contain at least one alicyclic diamine and / or alicyclic diacid in their constituent units X and Y.

[0057] Advantageously, the aliphatic polyamides are 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 preferably polyamide 6 (PA-6), polyamide 11 (PA -11) Selected from polyetheramide or polyether ester amide copolymer (PEBA) (or copolymer of polyamide block and polyether block) selected from 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.

[0058] Preferably, - The aliphatic polyamide is 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 preferably polyamide 11 (PA-11), polyamide 12 ( Selected from among polyetheramides or polyether ester amide copolymers (PEBA) (or copolymers of polyamide blocks and polyether blocks), including 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. - The semi-aromatic polyamide may be a semi-aromatic polyamide modified by urea units, particularly PA MXD6 and PA MXD10, or a semi-aromatic polyamide of formula X / YAr as described in EP1505099, particularly formula A / XT [wherein A is selected from a constituent unit derived from at least one amino acid, a constituent unit derived from at least one lactam, and at least one constituent unit corresponding to formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, where the constituent unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the constituent unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; XT is a semi-aromatic polyamide of the formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically the 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.

[0059] T corresponds to terephthalic acid, MXD to m-xylylenediamine, MPMD to methylpentamethylenediamine, and BAC to 1,3-bis(aminomethyl)cyclohexane.

[0060] 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.

[0061] Preferably, the polyamide is an aliphatic polyamide PA11 or PA12, and preferably PA11.

[0062] According to one alternative method, the polyamide is a polyetheramide or polyether esteramide copolymer (PEBA) (or a copolymer of a polyamide block and a polyether block). The polyamide blocks of these copolymers can 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 can be selected from PEG (polyethylene glycol), PPG (polypropylene glycol), PO3G (polytrimethylene glycol), PTMG (polytetramethylene glycol or polytetrahydrofuran), and combinations thereof. Such copolymers can be prepared according to either patent application FR2846332 in the name of ATOFINA or patent application EP1482011 in the name of UBE INDUSTRIE.

[0063] Preferably, at least one polyamide of the matrix resin of the present invention exhibits a polymolecular index Ip of 2 to 5, particularly 2 to 4, and especially 2 to 3. The polymolecular index, denoted as Ip, is measured by size exclusion chromatography or gel permeation chromatography and corresponds to the Mw / Mn ratio.

[0064] Optionally, the matrix resin composition includes at least one additive selected from among catalysts, antioxidants, heat stabilizers, ultraviolet stabilizers, light stabilizers, lubricants, release agents, fillers, plasticizers, flame retardants, nucleating agents, chain extenders, and colorants, conductive agents, thermal conductors, or mixtures thereof.

[0065] Advantageously, the additive is selected from among heat stabilizers, antioxidants, flame retardants, conductive agents, and thermal conductors.

[0066] The matrix resin composition may also include liquid crystal polymers or cyclopolymers (butylene terephthalate), or mixtures containing them. These compounds can fluidize the matrix resin in a molten state, allowing it to penetrate more effectively into the core of the fiber material.

[0067] The filler can be selected from, for example, carbon fillers, particularly carbon black or carbon nanofillers, and preferably from graphene, carbon nanotubes, carbon nanofibrils, or mixtures thereof. Particularly preferably, the matrix resin composition of the present invention contains no filler or contains less than 2% by weight of filler relative to the total weight of the matrix resin composition, preferably 0.02 to 0.1% by weight of filler.

[0068] Textile materials Preferably, the fibrous material consists of fibers, in particular, of mineral, organic, or plant origin, generally in the form of strands.

[0069] The fibers are preferably continuous fibers.

[0070] Examples of mineral-derived fibers include carbon fibers, glass fibers, basalt fibers, silica fibers, or silicon carbide fibers.

[0071] Advantageously, these are carbon fibers with a fiber count of 12K or more per strand (and therefore 12,000 filaments / strand), especially carbon fibers with a fiber count of 24K or more (24,000 filaments per strand), or glass fibers with a weight of 1200 tex or more, especially 2400 tex or more.

[0072] Examples of plant-derived fibers include those based on flax, hemp, lignin, bamboo, silk (especially spider silk), or sisal, or cellulose fibers (especially viscose). These plant-derived fibers can be used in their pure form, treated form, or coated form with a coating layer to promote adhesion and impregnation of the matrix resin composition.

[0073] Examples of organic fibers include amorphous thermoplastic fibers whose glass transition temperature Tg is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition if the polymer is semicrystalline, and whose Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition; or semicrystalline thermoplastic fibers whose melting temperature Tf is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition, and whose Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition; or a mixture of two or more of the above fibers, preferably a mixture of carbon fibers, glass fibers, or silicon carbide fibers, particularly carbon fibers.

[0074] Preferably, the fibers are mineral fibers, particularly carbon fibers, glass fibers, or a mixture of silicon carbide fibers, and especially carbon fibers.

[0075] Textile materials can be fabrics made by knitting or weaving fibers.

[0076] It can also correspond to fibers that have supporting threads.

[0077] These constituent fibers can be used individually or in combination. Therefore, organic fibers can be mixed with mineral fibers and impregnated with a thermoplastic prepolymer (including a chain extender if necessary) to form an impregnated fiber material.

[0078] Organic fiber strands can have multiple weights and can also exhibit multiple shapes. Fibers can exist in the form of short fibers, which constitute felt or nonwoven fabrics, which may be in the form of strips, mats, or fragments; or they can exist in the form of continuous fibers, which constitute 2D fabrics, braids, or unidirectional (UD) fiber strands or nonwoven fabrics. The constituent fibers of a fibrous material can also exist in the form of a mixture of these reinforcing fibers of different shapes. Preferably, the fibers are continuous.

[0079] Preferably, the fibrous material consists of continuous carbon fibers, glass fibers, or silicon carbide fibers, or mixtures thereof, particularly carbon fibers. It is used in the form of one strand or multiple strands.

[0080] In one embodiment, the matrix resin composition is dispersed as uniformly as possible within the fibers to obtain the minimum porosity, in other words, the minimum voids between fibers. In fact, the presence of porosity in this type of material can act, for example, as stress concentration points during mechanical tensile stress, which then form fracture initiation points in the impregnated fiber material, thereby mechanically weakening it. Therefore, the uniform distribution of the matrix resin composition improves the mechanical strength and uniformity of the composite material (component (C1)) formed from these impregnated fiber materials.

[0081] 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.

[0082] The impregnation rate can be measured by dividing the surface area of ​​the component (C1) impregnated with the matrix resin composition by the total surface area of ​​the product (impregnated surface area including matrix resin and fibers + porous surface area) by image analysis of the cross-section of the component (C1) (particularly using a microscope, camera, or digital camera). To obtain a good quality image, it is preferable to coat the transversely cut component (C1) with a standard low-temperature polymerizable polishing resin and polish it according to a standard protocol so that the sample can be observed under at least 6x microscope magnification.

[0083] Advantageously, the porosity of the impregnated fiber material (component (C1)) is less than 10%, particularly less than 5%, and particularly less than 2%.

[0084] It is difficult to achieve (or measure) zero porosity, and consequently, it should be noted that, advantageously, the porosity is greater than 0%, but less than the rate mentioned above.

[0085] The porosity corresponds to the closed porosity and can be determined by electron microscopy or as the relative difference between the theoretical density and experimental density of the impregnated fibrous material, as described in the section of the embodiments of the present invention.

[0086] The component (C1) can be obtained from a fibrous material by any method known to those skilled in the art, in particular by, for example, coating on a fluid bed, impregnation in an aqueous or solvent dispersion of polymer powder, extrusion molding in a polymer molten material (or melting path), or dry powder spraying, excluding spontaneous electrostatic pulverization.

[0087] Particularly preferably, the component (C1) of the present invention can be obtained according to the method described in International Publication No. 2018 / 234436, and especially preferably according to the fluidized bed method described on pages 15-21 of International Publication No. 2018 / 234436.

[0088] Overmolding resin composition The overmolding resin composition according to the present invention comprises at least one polymer selected from polyamides. The polyamide is preferably as defined above.

[0089] If the overmolding resin composition contains at least one polyamide, it may be the same as or different from the polyamide in the matrix resin composition.

[0090] Preferably, the polymer of the overmolding resin composition and the polymer of the matrix resin composition have the same chemical properties (especially functional groups) and the same physical properties.

[0091] Preferably, the polymer of the overmolding resin composition and the polymer of the matrix resin composition are the same.

[0092] In a particularly preferred embodiment, - The matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, for example, PA11, and the overmolding resin comprises PEBA; or - The matrix resin comprises an aliphatic polyamide, preferably PA11 or PA12, for example, 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, for example, 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, for example, PA11.

[0093] Optionally, the overmolding resin composition includes at least one additive selected from among catalysts, antioxidants, heat stabilizers, ultraviolet stabilizers, light stabilizers, lubricants, release agents, fillers, plasticizers, flame retardants, nucleating agents, chain extenders, and colorants, conductive agents, thermal conductors, or mixtures thereof.

[0094] Advantageously, the additive is selected from among heat stabilizers, antioxidants, flame retardants, conductive agents, and thermal conductors.

[0095] The surface resin composition may also include liquid crystal polymers or cyclopolymers (butylene terephthalate), or mixtures containing them. These compounds can fluidize the matrix resin in a molten state, allowing for better penetration into the core of the fibrous material.

[0096] The filler can be selected from, for example, carbon fillers, particularly carbon black or carbon nanofillers, and preferably from graphene, carbon nanotubes, carbon nanofibrils, or mixtures thereof. In a particularly preferred embodiment, the overmolding resin composition of the present invention contains 0.01% to 2% by weight of the filler, preferably 0.01% to 0.5% by weight of the filler, based on the total weight of the overmolding resin composition.

[0097] The overmolding resin composition may also contain fibers, more preferably short fibers, preferably short glass fibers or short carbon fibers.

[0098] The fibers, before the composition is implemented, preferably have a length between 2 and 13 mm, and more preferably between 3 and 8 mm.

[0099] The component (C2) can be in the form of a foam, which in turn allows for weight reduction. The terms “foam” or “polymer foam” refer to a two-phase material comprising a continuous phase consisting of a polymer matrix and a continuous or discontinuous gas phase. A foam is said to be closed-porous if the polymer matrix is ​​the only continuous phase of the system. The gas exists only in the form of individual bubbles. Otherwise, in an open-porous foam, the gas phase and the polymer phase are continuous. The foam according to the present invention can be prepared by mixing an overmolded resin with a leavening agent (and optionally one or more additives), and then carrying out a foaming process. The leavening agent can be a chemical or physical agent, and may consist of any type of hollow object or any type of inflatable microsphere. For example, but not limited to, a physical leavening agent may be nitrogen or carbon dioxide, or hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons or hydrochlorofluorocarbons (saturated or unsaturated), or mixtures thereof. The physical leavening agent may exist in gaseous, liquid, or supercritical form, in which case it is converted to the gas phase during the foaming process. This same foaming process can be caused by thermodynamic instability of the pressure and / or temperature jump type. In the case of polyamide, the foam in particular exhibits a density of 1000 kg / m³ or less, preferably 800 kg / m³ or less, preferably 600 kg / m³ or less, preferably 500 kg / m³ or less, preferably 400 kg / m³ or less, and in a more particularly preferred embodiment, 300 kg / m³ or less, and ideally 200 kg / m³ or less. The foam density can be controlled by adapting the parameters of the preparation method in particular, according to techniques known to those skilled in the art. The density is measured by immersion in water (23°C) according to ISO 1183-1.

[0100] Preferably, the thickness of component (C1) is between 0.07 and 50 mm, preferably between 0.15 and 50 mm, 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, preferably between 0.5 and 10 mm, preferably between 0.5 and 5 mm, preferably between 0.15 and 2 mm.

[0101] In a particularly advantageous embodiment, the overmolded composite material structure of the present invention does not contain an adhesive primer between components (C1) and (C2). Therefore, in a particularly advantageous embodiment, components (C1) and (C2) in the overmolded composite material structure are in direct contact without an intermediate layer. The bonding force between components (C1) and (C2) is provided by a specific selection of polyamide in the matrix resin composition as defined above.

[0102] The absence of an adhesive primer facilitates the recycling of overmolded composite structures. Recycling can be carried out, in particular, by crushing 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 the form of pellets. Recycling can also be carried out by decomposing the two components (C1) and (C2), for example by heating or cooling, and then recycling or reusing the components (C1) and (C2) separately.

[0103] The term "adhesion primer" refers to a compound that, when applied to a support (in this case, component (C1)) and intended to receive a second support (in this case, component (C2)), enables strengthening of the bond between the two supports, thereby creating a chemical and / or physical bond between the two supports, resulting in strong adhesion between the supports, thereby enabling solidification, and thus increasing the adhesion of component (C2) to component (C1). Such adhesion primers are selected from, for example, epoxides, combinations of epoxides, ethyl silicates, aromatic or aliphatic polyurethanes, and mixtures thereof, for example, aromatic or aliphatic polyurethanes, epoxides, and mixtures of aromatic or aliphatic polyurethanes and epoxides.

[0104] Preferably, the overmolded composite material structure does not contain an adhesive primer selected from epoxides, combinations of epoxides, ethyl silicates, aromatic or aliphatic polyurethanes, and mixtures thereof, for example, aromatic or aliphatic polyurethanes, epoxides, or mixtures of aromatic or aliphatic polyurethanes and epoxides.

[0105] method This application also relates to a method for producing an overmolded composite material structure according to the present invention, comprising the step of overmolding a component (C2) onto at least a portion of the surface (S) of a component (C1). The overmolding method is known to those skilled in the art. Thus, the second component (C2) is molded in a mold containing a pre-made component (C1). The overmolding resin composition is introduced in a molten state.

[0106] Any overmolding technique known to those skilled in the art can be employed. In a preferred embodiment, the overmolding of the method of the present invention is carried out by injection molding (the overmolding resin composition is injected into a mold).

[0107] The component (C1) is manufactured by any technique known to those skilled in the art before carrying out the method of the present invention. The component (C1) can be shaped before the overmolding step.

[0108] In an advantageous embodiment, the method of the present invention does not involve the step of assembling components (C1) and (C2) using an adhesive primer.

[0109] In a preferred embodiment, the method of the present invention does not require heating the component (C1) before the overmolding step. Preferably, the mold during the overmolding step is heated to the highest temperature corresponding to the Tg + 40°C of the matrix resin composition.

[0110] Purpose The present invention also relates to the use of the above-mentioned overmolded composite material structure for the manufacture of components, particularly in the fields of machinery, aerospace, ships, automobiles, oil and gas (especially offshore and gas storage), energy, health and medical, sports and leisure, and electronics.

[0111] The present invention also relates to the use of a matrix resin composition as defined above for the preparation of an overmolded composite material structure comprising a first component (C1) comprising at least one fibrous material and the matrix resin composition, and a second component (C2) comprising an overmolding resin composition, wherein the use improves the adhesion between component (C1) and component (C2).

[0112] The present invention also relates to the use of the matrix resin composition as defined above for the preparation of an overmolded composite material structure comprising a first component (C1) comprising at least one fibrous material and the matrix resin composition, and a second component (C2) comprising an overmolding resin composition, wherein a peel strength of 50 N / cm or more, preferably 70 N / cm or more, and particularly preferably 100 N / cm or more is obtained between component (C1) and component (C2) according to a suitable protocol of ISO 4578:1997 (90° peel).

[0113] The present invention also relates to the use of a matrix resin composition as defined above for the preparation of an overmolded composite material structure comprising a first component (C1) comprising at least one fibrous material and the matrix resin composition; and a second component (C2) comprising an overmolding resin composition, wherein no adhesive primer is required between the component (C1) and the component (C2).

[0114] The present invention will be described in more detail in the following embodiments. [Examples]

[0115] Examples Unless otherwise specified, percentages are expressed as weight relative to the total weight of the composition.

[0116] Example 1 Preparation of constituent elements (C1) (also called composite materials): All composite materials are unidirectional composites, meaning that all reinforcing fibers are oriented in the same direction. The fibers used consist of carbon filaments with a unit diameter of 7 μm. These carbon fibers initially consist of 24,000 filaments each and are impregnated using the so-called fluidized bed powder method with polyamide 11 (PA11) powder of the same average particle size D50 = 108 μm, as described in International Publication No. 2018 / 234436. The powder is pre-added with 0.1 wt% Monarch 800 carbon black (Cabot). The resulting pre-impregnated material has an average width of 98 mm and an average thickness of 145 μm, with an average fiber content of 55% vol + / - 1%, as measured by ASTM D3171-22.

[0117] The pre-impregnated material thus obtained is either used alone as component C1 at the output of the impregnation process, or multiple of these pre-impregnated materials are stacked in an automated stacking process (AFP) and then solidified under a hot press to produce a unidirectional composite material. Here, the material is placed on a solidification plateau at 210°C under a pressure of 10 bar for 3 minutes, and the resulting composite material is rapidly cooled by air quenching. The sample is named as follows: T01: Pre-impregnated material obtained by fluidized bed impregnation method P31:T01 Pre-impregnated material assembled, solidified under pressure for 3 minutes, and cooled by air quenching.

[0118] The final thickness of the P31 plates obtained in this way will be an average of 1.1 mm.

[0119] The composite material incorporated into the overmolding mold is 98x98mm 2 It is pre-cut into the specified format and dried for 24 hours under vacuum at 80°C.

[0120] Before being incorporated into the overmolding mold, the 7mm wide composite material pieces at the edges of the composite material are covered with a polyimide adhesive film to initiate demolding after overmolding.

[0121] Injection molding polymers and overmolding methods: The polymer used for injection molding is polyamide 11 of grade BESNO TL. Injection molding is performed using a vertical press with cavity dimensions of 100 x 100 x 2 mm. 3 The process is carried out using a mold and center-point injection molding. PA11 is injection molded at a barrel temperature of 290°C and a mold temperature of 80°C (approximately 100°C lower than the melting point of polyamide 11 used in the manufacture or injection molding of the composite material (matrix resin)). The holding pressure in these tests is 60% of the switch pressure and the holding time is 15 seconds.

[0122] Characterization of composite materials before overmolding: Fiber content measured according to ASTM D3171-22: 55% vol ± 1% vol Measurement of enthalpy of melting of matrix resin by DSC (ISO11357-3:2013) Measurement of the molecular weight (Mn) of matrix resin by GPC Measurement of the viscosity of the matrix resin described above.

[0123] Preparation of peel test specimens and peel test: Next, the resulting overmolded plate was cut in the longitudinal direction of the fibers, resulting in dimensions of 98 × 15 mm. 2 A peel test specimen (therefore, 98 mm corresponds to the length of the specimen in the fiber direction) is taken out.

[0124] Adhesion performance was measured according to the 90° peel method conforming to the aforementioned ISO 4578:1997. The setup used was load-bearing by a pulley plate and connected to a Criterion C42 dynamometer with a suitable force cell. The test was performed at a speed of 50 mm / min with a crosshead displacement of 50 mm. Five different test specimens were analyzed for each type of overmolded component.

[0125] result - In the case of examples B001 and B002, the polyamide 11 powder used in the impregnation method to create the component (C1) (also called composite material) is PA11 powder that exhibits the following properties before impregnation: 240°C, shear rate 1800 s -1 The melt viscosity is 0.5 Pa·s, Mn = 6200 g / mol (GPC molecular weight), and IP = 2.1.

[0126] - In the case of Example B003, the polyamide 11 powder used in the impregnation method to create the component (C1) (also called the composite material) is a non-reactive PA11 powder that exhibits the following properties before impregnation: 240°C, shear rate 1800 s -1 The melt viscosity is 0.7 Pa·s, Mn = 7500 g / mol (GPC molecular weight), and IP = 2.3.

[0127] - In the case of Example B004, the polyamide 11 powder used by the impregnation method to create the component (C1) (also called composite material) is PA11 powder that exhibits the following characteristics before impregnation: 240 °C, shear rate 1800 s -1 and the melt viscosity at = 1.3 Pa·s, Mn = 10100 g / mol (GPC molecular weight), IP = 2.1.

[0128] TIFF2026511032000003.tif199170TIFF2026511032000004.tif169170

[0129] All composite material data are measured before preheating the composite material.

[0130] The above examples show that the matrix resin of the present invention makes it possible to obtain a significant peel strength that guarantees good adhesion between components (C1) and (C2) without the need for an adhesion primer.

[0131] <于 Example 2 Preparation of component (C1) (also called composite material): All composite materials are unidirectional composite materials, which means that all reinforcing fibers are oriented in the same direction. The fibers used are composed of carbon filaments with a unit diameter of 7 μm. These carbon fibers were initially composed of 24,000 filaments each, and were impregnated by the so-called fluidized bed powder method using polyamide 11 (PA11) powder with the same average particle diameter D50 = 108 μm as described in International Publication No. 2018 / 234436. The powder is pre-added with 0.1% by weight of Monarch 800 carbon black (Cabot).

[0132] The obtained pre-impregnated material (or component C1) has an average width of 98 mm and an average thickness of 145 μm, and the average fiber content measured by ASTM D3171-22 is 55% vol + / - 1%.

[0133] Overmolding method The obtained component (C1) is cut to obtain a test piece with the following dimensions (length x width x height): 125 x 25 x 1.5 mm.

[0134] The test specimens are placed in a mold that can accommodate the specimen on one side and into which the polymer of the overmolding composition can be injected on the other side, in order to create a 25x25mm contact area between the composite material substrate and the overmolding surface composition. Representative diagrams of these test specimens are shown in Figure 2 (black represents the composite material (C1), and white represents the overmolding component (C2)).

[0135] Storage and analytical conditions After the overmolding process, the overmolded test specimens are conditioned in a sealed bag at 23°C for a minimum of 240 hours. After opening the bag, the test specimens are placed in a desiccator at room temperature until testing.

[0136] The offset support tensile tests were conducted under conditions close to those of the NF EN 1465 (2009) standard: details are as follows. Initial distance between jaws: 115mm Test speed: 1.3 mm / min o Test temperature: 23℃ ± 2℃ o Relative humidity: 50% + / - 10%

[0137] The breaking force is measured immediately upon fracture of the composite material / polymer interface.

[0138] The device used in the test was a ZWICK1455 dynamometer equipped with a 20kN cell.

[0139] The region of the composite material (C1) that will subsequently come into contact with the overmolding composition (C2) can be preheated before the overmolding process.

[0140] Overmolding is performed at a temperature of 260°C.

[0141] The matrix implemented in component (C1) is as follows: S1: The PA11 powder used in the impregnation method to create component (C1) is a reactive PA11 powder and exhibits the following properties before impregnation: 240°C, shear rate 1800 s. -1 Melt viscosity = 0.7 Pa·s, Mn = 7500 g / mol (GPC molecular weight), IP = 2.3 S2: The PA11 powder used in the impregnation method to create the component (C1) is a non-reactive PA11 powder and exhibits the following properties before impregnation: 240°C, shear rate 1800 s. -1 Melt viscosity = 0.4 Pa·s, Mn = 6200 g / mol (GPC molecular weight), IP = 2.1 S3: The PA11 powder used in the impregnation method to create component (C1) is a reactive PA11 powder and exhibits the following properties before impregnation: 240°C, shear rate 1800 s -1 Melt viscosity = 0.4 Pa·s, Mn = 5400 g / mol (GPC molecular weight), IP = 2.1 S4 (Comparison): The PA11 powder used in the impregnation method to create the component (C1) is a non-reactive PA11 powder and exhibits the following properties before impregnation: 240°C, shear rate 1800 s. -1 Melt viscosity = 205 Pa·s, Mn = 39500 g / mol (GPC molecular weight), IP = 2.1

[0142] The results obtained are shown in the table below: TIFF2026511032000005.tif237170

[0143] TIFF2026511032000006.tif106170

[0144] The tests demonstrate that by mounting the matrix resin according to the present invention onto component C1 for the preparation of an overmolded composite material, good adhesion can be obtained without preheating component C1 before the overmolding process. The tests also demonstrate that preheating component C1 improves adhesion compared to overmolded composite materials containing a matrix resin different from that of the present invention.

Claims

1. An overmolded composite material structure, i) A first component (C1) comprising at least one fibrous material and a matrix resin composition, wherein the matrix resin composition comprises at least one polyamide, and the at least one polyamide has a number average molecular weight Mn between 3,000 g / mol and 35,000 g / mol, preferably between 5,000 g / mol and 20,000 g / mol, preferably between 5,000 g / mol and 15,000 g / mol, more preferably between 5,000 g / mol and 10,000 g / mol, and a shear rate of 1800 s －１ The first component (C1), wherein the melt viscosity measured by capillary rheology at Tf + 50°C (where Tf is the melting temperature of at least one of the polyamides) is between 0.05 Pa·s and 1000 Pa·s, preferably between 0.1 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 1000 Pa·s, preferably between 0.3 Pa·s and 500 Pa·s, more preferably between 0.3 Pa·s and 250 Pa·s, for example between 0.3 Pa·s and 100 Pa·s, even more preferably between 0.3 Pa·s and 50 Pa·s, even more preferably between 0.3 Pa·s and 25 Pa·s, even more preferably between 0.3 Pa·s and 10 Pa·s, preferably between 0.3 Pa·s and 5 Pa·s; and ii) A second component (C2) comprising an overmolding resin composition. Includes, An overmolded composite material structure wherein the first component C1 includes at least one surface S, and the component C2 is bonded to the component C1 on at least a portion of the surface S.

2. The polyamide is an aliphatic, alicyclic, or semi-aromatic polyamide: - Here, 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 polyetheramide or polyether esteramide copolymer (PEBA) (or copolymer of polyamide block and polyether block), or - Semi-aromatic polyamides are semi-aromatic polyamides optionally modified with urea units, particularly PA MXD6 and PA MXD10, or formula A / XT [wherein A is selected from a constituent unit derived from at least one amino acid, a constituent unit derived from at least one lactam, and at least one constituent unit corresponding to formula (Ca diamine) - (Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, the constituent unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the constituent unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; X. A semi-aromatic polyamide of formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically polyamides PA6 / 6T, PA66 / 6T, PA6I / 6T, PAMPMDT / 6T, PA11 / 10T, PA11 / 6T / 10T, PAMXDT / 10T, PAMPMDT / 10T, PABACT / 10T, PABACT / 6T, PA11 / BACT, PABACT / 10T / 6T, PA The formula is 11 / BACT / 10T; T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane. The overmolded composite material structure according to claim 1.

3. The at least one type of polyamide is - Aliphatic polyamide 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 aliphatic polyamides selected from polyetheramide or polyether ester amide copolymer (PEBA) (or copolymer of polyamide block and polyether block), or - Semi-aromatic polyamides that may be modified by urea units, particularly PA MXD6 and PA MXD10, or formula A / XT [wherein A is selected from at least one structural unit derived from at least one amino acid, at least one structural unit derived from at least one lactam, and at least one structural unit corresponding to formula (Ca diamine) - (Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, where a and b are between 4 and 36, preferably between 9 and 18, where the structural unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the structural unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; X. A semi-aromatic polyamide of formula A / 6T, A / 9T, A / 10T, or A / 11T [where A is as defined above], specifically polyamides PA6 / 6T, PA66 / 6T, PA6I / 6T, PAMPMDT / 6T, PA11 / 10T, PA11 / 6T / 10T, PAMXDT / 10T, PAMPMDT / 10T, PABACT / 10T, PABACT / 6T, PA11 / BACT, PABACT / 10T / 6T, PA The compound is 11 / BACT / 10T, where T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to 1,3-bis(aminomethyl)cyclohexane, and is a semi-aromatic polyamide. An overmolded composite material structure according to claim 1 or 2, selected from among the following.

4. An overmolded composite material structure according to any one of claims 1 to 3, wherein 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, PA 11 / MXDT / 10T.

5. The overmolded composite material structure according to any one of claims 1 to 3, wherein the polyamide is PA11 or PA12, preferably PA11.

6. At least one polyamide is an amorphous or semi-crystalline polyamide in which the absolute value of the enthalpy of melting in the component (C1) before overmolding is less than 12 J per gram of matrix resin, preferably less than 8 J per gram of matrix resin, and preferably less than 5 J per gram of matrix resin, calculated according to formula (1). Formula (1): Enthalpy measurements were performed by differential scanning calorimetry (DSC) in accordance with ISO 11357-3 of 2013. The melting and crystallization peaks are the first heating peaks at a rate of 20 K / min. The overmolded composite material structure according to claim 1 or 5.

7. The overmolded composite material structure according to any one of claims 1 to 3, wherein the overmolded resin composition comprises at least one polymer selected from polyamides that are the same as or different from the polyamide of the surface resin composition, or from polyetheramides or polyether ester amide copolymers.

8. - 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 contains a semi-aromatic polyamide, and the overmolding resin contains an aliphatic polyamide, preferably PA11 or PA12, preferably PA11. An overmolded composite material structure according to any one of claims 1 to 7.

9. Fiber materials, - Mineral-derived fibers such as carbon fiber, glass fiber, silicon carbide fiber, basalt fiber, and silica fiber; - Plant-derived fibers, especially those based on flax, hemp, lignin, bamboo, silk (especially spider silk), or sisal, and cellulose fibers (especially viscose); - Organic-derived fibers, for example, amorphous thermoplastic fibers, in which the glass transition temperature Tg is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition if the polymer is semicrystalline, and the Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition; or semicrystalline thermoplastic fibers, in which the melting temperature Tf is higher than the Tg of the polymer in the matrix resin composition if the polymer is amorphous, or higher than the Tf of the polymer in the matrix resin composition, and the Tg (in the case of amorphous) or Tf (in the case of semicrystalline) of the fiber is higher than the injection temperature of the overmolded resin composition. - Or, a mixture of two or more of the above fibers, preferably a mixture of carbon fibers, glass fibers, or silicon carbide fibers, particularly carbon fibers. An overmolded composite material structure according to any one of claims 1 to 8, comprising continuous fibers selected from among.

10. An overmolded composite material structure according to any one of claims 1 to 9, characterized in that no adhesive primer is included between constituent elements C1 and C2.

11. The overmolded composite material structure according to any one of claims 1 to 10, wherein the matrix resin composition contains no filler or contains less than 2% by weight of a filler relative to the weight of the matrix resin composition, preferably containing 0.02 to 0.1% by weight of a filler.

12. A method for manufacturing an overmolded composite material structure according to any one of claims 1 to 11, comprising the step of overmolding a component C2 onto at least a portion of the surface S of a component C1.

13. The method according to claim 12, wherein the overmolding process is an injection overmolding process.

14. Use of an overmolded composite material structure according to any one of claims 1 to 11, particularly for the manufacture of components in the fields of machinery, aviation, ships, automobiles, oil and gas (particularly offshore, gas storage), energy, health and medicine, sports and leisure, and electronics.

15. Use of the matrix resin composition according to any one of claims 1 to 6, 8, and 11 for the preparation of an overmolded composite material structure comprising a first component C1 comprising at least one fibrous material and the matrix resin composition, and a second component C2 comprising an overmolding resin composition, wherein a peel strength of 50 N / cm or more, preferably 70 N / cm or more, and particularly preferably 100 N / cm or more is obtained between component C1 and component C2, as measured according to a suitable protocol of ISO 4578:1997 (90° peel).

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