A bio-based polyamide composite sheet material, and a method of making and use thereof

Abstract

The application discloses a kind of bio-based polyamide composite boards, it includes first surface layer, middle layer and second surface layer;The first surface layer, middle layer and second surface layer are sequentially stacked;The first surface layer and second surface layer are long carbon chain polyamide resin unidirectional prepreg tape, and the middle layer is the composite material layer of bio-based polyamide 56 silk glass fiber blended fabric and fiber cloth.The compression molding of the composite board guarantees the processing rate and efficient forming of the board, improves the mechanical properties and heat distortion temperature of the composite board, reduces the water absorption of the composite board, and the overall quality is light, more meets the demand of lightweight board.

Description

[0001] The present application claims priority from Chinese Patent Application No. 2021110369262, filed on September 6, 2021, and entitled "A Bio-based Polyamide Composite Board and Its Preparation Method and Application", and Chinese Patent Application No. 2021221405126, filed on September 6, 2021, and entitled "A Bio-based Polyamide Composite Board". The present application incorporates the entire text of the above-mentioned Chinese patent applications by reference. TECHNICAL FIELD

[0002] The present application relates to a bio-based polyamide composite board and its preparation method and application. BACKGROUND

[0003] Composite materials play an important role in many fields and also replace many traditional materials. The main composite material forming process methods include winding forming, laying forming, mold pressing forming, autoclave forming and resin transfer molding, etc. The composite material forming process usually includes two stages, first, the raw material is deformed or flowed under certain temperature and pressure to obtain the required shape, and then the shape is maintained. Different forming methods can be selected according to different raw materials. The mold pressing forming method is relatively simple and efficient. The mold pressing forming process of composite materials mainly includes: forming mold design, layer design, composite material component forming, mold pressing forming process characteristics, factors affecting the quality of mold pressing products, etc. The board prepared by the mold pressing forming of the composite material is applied in various fields.

[0004] Bio-based polyamide resin is a semi-crystalline thermoplastic polymer, part or all of the monomers in the synthesis are derived from biomass, which has the characteristics of sustainable raw material source, green and environmentally friendly preparation process, and reusable and recyclable product. It can maintain high rigidity and strength at high temperature, and is an excellent fiber-reinforced thermoplastic composite resin.

[0005] The injection molding method is easy to damage the glass fiber structure due to secondary heating and the shearing effect of the screw on the glass fiber, thereby affecting the final performance of the composite material. The PVC wood-plastic composite board has a low use temperature, small modulus, poor strength, and high water absorption rate due to the limitation of the resin matrix. The processing cost of thermosetting composite materials is high due to the influence of the forming process, and the heat resistance is poor. Therefore, in order to make the polyamide composite material adapt to more complex use occasions, broaden the use temperature, reduce the influence of water absorption, and increase the lightweight, it is necessary to design and develop a composite board with high strength, high heat distortion temperature, and low water absorption rate and its preparation process. SUMMARY

[0006] In order to improve the performance of the existing polyamide composite board and broaden the use scene, the application provides a bio-based polyamide composite board and a preparation method and application thereof. The bio-based polyamide composite board of the application performs mold forming on the mixed woven fabric of bio-based polyamide filaments and glass fibers, the fiber cloth and the bio-based polyamide unidirectional prepreg tape, ensures the processing rate and efficient forming of the board, improves the mechanical properties and thermal deformation temperature of the composite board, reduces the water absorption of the composite board, and the overall quality is light, which further meets the demand for light weight board.

[0007] The relative viscosity is determined by the Ubbelohde viscometer concentrated sulfuric acid method (96%). The bio-based content is determined by carbon 14, for example, obtained by detecting the bio-based content by the standard method ASTM D6866.

[0008] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0009] One of the technical solutions: a bio-based polyamide composite board, comprising a first surface layer, an intermediate layer and a second surface layer; the first surface layer, the intermediate layer and the second surface layer are sequentially stacked; the first surface layer and the second surface layer are long carbon chain polyamide resin unidirectional prepreg tapes, and the intermediate layer is a composite material layer of bio-based polyamide 56 filament glass fiber blended fabric and fiber cloth.

[0010] Long carbon chain polyamide resin unidirectional prepreg tape:

[0011] In the application, the long carbon chain polyamide resin unidirectional prepreg tape can be a material known in the art.

[0012] In some specific embodiments, the long carbon chain polyamide resin unidirectional prepreg tape is a continuous long fiber reinforced long carbon chain polyamide resin unidirectional prepreg tape, which comprises continuous long fibers and bio-based long carbon chain polyamide 5X resin; the mass percentage of the continuous long fibers is 40-80%, more preferably 60-70%, for example, 32.8%, the mass percentage refers to the mass of the continuous long fibers accounting for the mass of the prepreg tape.

[0013] In some specific embodiments, the bio-based long carbon chain polyamide 5X resin is selected from one or more of PA510, PA511, PA512, PA513, PA514, PA515, PA516, PA517 and PA518. Among them, the relative viscosity of the bio-based long carbon chain polyamide resin is 1.8-2.7, preferably 2.1-2.8; the end amino content is 42-60 mmol / kg; the melting point is 170℃-320℃, preferably 180-230℃; the bio-based content is 28%-100%.

[0014] In some specific embodiments, the bio-based long carbon chain polyamide 5X resin is PA510, with a viscosity of 2.51, an end amino group content of 54 mmol / kg, and a melting point of 217°C.

[0015] In some specific embodiments, the bio-based long carbon chain polyamide 5X resin is PA512, with a viscosity of 2.32, an end amino group content of 56 mmol / kg, and a melting point of 210°C.

[0016] In some specific embodiments, the continuous long fiber can be a continuous long fiber that is conventionally commercially available in the art, and the kind can be conventional in the art, such as carbon fiber, glass fiber, basalt fiber, or aramid fiber.

[0017] In some specific embodiments, the continuous long fiber is a continuous long glass fiber, and the monofilament diameter can be 8-20 μm, preferably 8-15 μm or 15-20 μm, more preferably 8-10 μm. The linear density of the continuous long glass fiber is 500-3600 Tex, preferably 1200 Tex, 2400 Tex. The continuous long glass fiber is, for example, a continuous long glass fiber with a specification of 1200 Tex purchased from Owens Corning (OC), or a continuous long glass fiber with a specification of 2400 Tex purchased from Giant Stone.

[0018] In some specific embodiments, the continuous long fiber is a continuous long carbon fiber. The continuous long carbon fiber is preferably a polyacrylonitrile-based carbon fiber. The number of monofilaments of the continuous long carbon fiber can be 8000-50000, preferably 20000-30000, more preferably 8000, 12000 (12K), 24000 (24K), 45000. The monofilament diameter of the continuous long carbon fiber can be 5-10 μm, preferably 6-8 μm. The continuous long carbon fiber is, for example, a Toray T700 with a specification of 24K, or a Guangwei composite continuous long carbon fiber 700S with a specification of 12K or 24K.

[0019] In some specific embodiments, the long carbon chain polyamide resin unidirectional prepreg tape is prepared by a melt impregnation method. The melt impregnation method can be a conventional melt impregnation method in the art.

[0020] In some specific embodiments, the melt impregnation method comprises the following steps:

[0021] S1, the long carbon chain polyamide 5X resin containing long carbon chain polyamide resin composition is stirred and mixed, and a twin-screw extruder (the length-diameter ratio is preferably 1:36) is extruded. The extrusion temperature can be 170-340°C. The melt is filtered by a melt filter, and the melt enters the impregnation die. Preferably, the twin-screw extruder adopts an eight-zone heating mode. The temperatures of zones one to eight (from feeding to the die head) are 195-260°C, 255-305°C, 255-325°C, 255-325°C, 255-325°C, 255-325°C, 255-325°C, and 255-325°C, respectively.

[0022] S2, the continuous long fiber is introduced into the impregnation die, and the melt and the continuous long fiber are impregnated. The temperature of the impregnation die can be 240-335°C. The introduction preferably includes the following processes: the continuous long fiber is unwound from a creel through a tension controller, passes through a yarn separator frame, enters a spreader system to fully spread each towpiece, then enters a yarn drying device for preheating, and then enters the impregnation die to impregnate the continuous long fiber with the melt. The temperature of the yarn drying device is preferably 70-400°C.

[0023] S3, the impregnated continuous long fiber is shaped, cooled, pulled, and wound to obtain the long carbon chain polyamide resin unidirectional prepreg tape.

[0024] In some specific embodiments, the shaping and cooling can be performed by a four-roll machine as conventional in the art. The four-roll machine mainly includes a shaping roll and a cooling roll. The shaping roll functions as secondary impregnation and cooling shaping, and the cooling roll functions as cooling shaping. The temperature of the internal circulating oil in the shaping roll can be 30-250°C, such as 90°C, 120°C, 150°C, or 180°C. The temperature of the internal circulating water in the cooling roll can be 15-90°C, preferably 15-40°C, such as 20°C, or 60-90°C, such as 80°C. The pulling can be performed by a pulling device as conventional in the art, in which further cooling and edge cutting are performed. The pulling speed can be 5-15 m / min. The winding can be performed by a winding device as conventional in the art, which is preferably an automatic winding machine. The winding speed can be 5-15 m / min.

[0025] In some specific embodiments, the long carbon chain polyamide resin composition comprises the following components by weight: the long carbon chain polyamide 5X resin 90-95 parts, the antioxidant 0.4-0.6 parts, the lubricant 0.3-0.5 parts, the compatibilizer 4-8 parts, and the coupling agent 0.4-0.5 parts. Wherein, the antioxidant is preferably selected from one or more of antioxidant 168, antioxidant 1098, antioxidant 1010, and antioxidant S9228. Wherein, the lubricant comprises WAXC and WAXE. Wherein, the compatibilizer can be selected from one or more of PP-g-MAH, POE-g-MAH, POE-g-GMA, or EPDM-g-MAH. Wherein, the coupling agent can be selected from one or more of coupling agent KH550, coupling agent KH560, or coupling agent KH570.

[0026] In some specific embodiments, the long carbon chain polyamide resin unidirectional prepreg tape has a thickness of 0.15-0.5 mm, preferably 0.21-0.33 mm, for example 0.31 mm, 0.32 mm, 0.33 mm.

[0027] In some specific embodiments, the long carbon chain polyamide resin unidirectional prepreg tape can be a polyamide glass fiber composite prepreg tape, a polyamide aramid fiber composite prepreg tape, a polyamide basalt fiber composite prepreg tape, a polyamide boron fiber composite prepreg tape, or a polyamide carbon fiber composite prepreg tape.

[0028] In some specific embodiments, the long carbon chain polyamide resin unidirectional prepreg tape can be a continuous long glass fiber reinforced long carbon chain polyamide thermoplastic unidirectional prepreg tape or a continuous long carbon fiber reinforced long carbon chain polyamide thermoplastic unidirectional prepreg tape, for example the continuous long fiber reinforced long carbon chain polyamide resin unidirectional prepreg tape disclosed in the invention patent CN113232384A.

[0029] Bio-based polyamide 56 filament glass fiber blended fabric:

[0030] In the present invention, the bio-based polyamide 56 filament glass fiber blended fabric can be a material known in the art.

[0031] In the present invention, the bio-based polyamide 56 filament glass fiber blended fabric is prepared by blending bio-based polyamide 56 filament / glass fiber mixed yarn, the bio-based polyamide 56 filament / glass fiber mixed yarn is prepared by mixing bio-based polyamide 56 filament and glass fiber, and the mass ratio of the bio-based polyamide 56 filament and the glass fiber is 1:0.15-4.

[0032] In some specific embodiments, in the bio-based polyamide 56 filament / glass fiber mixed yarn, the linear density ratio of the bio-based polyamide 56 filament and the glass fiber is 1:0.15-4, preferably 1:1.

[0033] In some specific embodiments, the bio-based polyamide 56 filament is prepared according to the method disclosed in Chinese invention patent CN110373736 A.

[0034] In some specific embodiments, the bio-based polyamide 56 filament has a breaking strength of 2.5-5.5 cN / dtex, an elongation at break of 40-100%, and a dry heat shrinkage of 5-10%.

[0035] In some specific embodiments, the glass fiber is a continuous long glass fiber.

[0036] In some specific embodiments, the glass fiber has a monofilament diameter of 5-20 pm.

[0037] In some specific embodiments, the glass fiber has a linear density of 1000-3600 Tex, for example 1200 Tex, 2400 Tex.

[0038] In some specific embodiments, the glass fiber has a moisture content of <0.10%.

[0039] In some specific embodiments, the bio-based polyamide 56 filament / glass fiber hybrid filament is obtained by twisting the bio-based polyamide 56 filament and the glass fiber through a twisting machine.

[0040] In some specific embodiments, the warp and weft yarns of the bio-based polyamide 56 filament / glass fiber hybrid fabric are both bio-based polyamide 56 filament / glass fiber hybrid filaments.

[0041] In some specific embodiments, the warp and weft yarns of the bio-based polyamide 56 filament / glass fiber hybrid fabric have a linear density ratio of 1:0.5-3, preferably 1:1.

[0042] In some specific embodiments, the bio-based polyamide 56 filament / glass fiber hybrid fabric has a tensile strength of above 300 Mpa, and / or a tensile modulus of above 13 Gpa, preferably above 16 Gpa, and / or a tensile strain of below 5%, and / or a moisture content of below 1.5%.

[0043] In some specific embodiments, the bio-based polyamide 56 filament / glass fiber hybrid fabric is obtained by bi-directional hybrid spinning of the bio-based polyamide 56 filament / glass fiber hybrid filament through a rapier loom (for example, a flexible rapier loom of GA731B-210 type), specifically, the weaving process parameters are as follows: weaving speed 300-310 r / min; back rest height 1020-1050 mm, drop height 60-70 mm, front and back 130-140 mm; harness flat time 300 s-320 s.

[0044] In some embodiments, the bio-based polyamide 56 filament glass fiber blended cloth warp and weft yarns are cross-stitched.

[0045] Fiber cloth:

[0046] In the present application, the fiber cloth can be a material known in the art. In some embodiments, the fiber cloth comprises any one or more of a woven cloth, unidirectional cloth, unidirectional prepreg, bidirectional prepreg, or multi-axial cloth made of carbon fiber, glass fiber, basalt fiber, or aramid fiber.

[0047] In some embodiments, the fiber cloth is a glass fiber cloth, such as a plain weave glass fiber cloth or a twill weave glass fiber cloth, for example, commercially available under the trade name EWR400 or EWR500T3 from China Giant Stone Co., Ltd.

[0048] In some embodiments, the fiber cloth has a thickness of 0.1-0.4 mm, preferably 0.175-0.193 mm. For example, a three-oz. right twill glass fiber cloth with a thickness of 0.175 mm or a twill glass fiber cloth with a thickness of 0.185 mm.

[0049] In some embodiments, the intermediate layer is an alternating layer of bio-based polyamide 56 filament glass fiber blended cloth and fiber cloth.

[0050] In some embodiments, the first and second surface layers each have one or more layers, for example, two, three, four or more layers. For example, the first and second surface layers each have one layer of long carbon chain polyamide resin unidirectional prepreg, or each have two layers of long carbon chain polyamide resin unidirectional prepreg cross-laid.

[0051] In some embodiments, the intermediate layer has three or more layers, for example, four, five or more layers. For example, when the intermediate layer has three layers, the bio-based polyamide 56 filament glass fiber blended cloth and fiber cloth are alternately laid, and the intermediate layer is sequentially: PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth. For example, when the intermediate layer has 15 layers, the PA56 filament and fiber cloth are alternately laid, and the intermediate layer is sequentially: PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth.

[0052] In some specific embodiments, the total number of layers of the first surface layer, the intermediate layer and the second surface layer is 5 layers or more, for example, the total number of layers is 5-200 layers, for example, 13 layers, 17 layers, 29 layers, 33 layers. When the total number of layers is 5, the bio-based polyamide composite board material from the first surface layer is: long carbon chain polyamide resin unidirectional prepreg tape-PA56 filament glass fiber blended cloth-fiber cloth-PA56 filament glass fiber blended cloth-long carbon chain polyamide resin unidirectional prepreg tape.

[0053] The number of layers described in the present application is an integer.

[0054] In some specific embodiments, different total number of layers can be set according to the thickness of the composite board to be molded.

[0055] In some specific embodiments, the thickness of the bio-based polyamide composite board material is 0.5 mm or more.

[0056] In some specific embodiments, the thickness of the bio-based polyamide composite board material is 2-40 mm, for example, 2 mm, 4 mm, 10 mm.

[0057] Technical solution two: a preparation method of a bio-based polyamide composite board, the first surface layer, the intermediate layer, and the second surface layer are sequentially laid and then molded, the molding temperature is 170-310℃, and the pressure is 0-5Mpa. In some specific embodiments, the bio-based polyamide 56 filament glass fiber blended cloth and the fiber cloth of the intermediate layer are alternately laid.

[0058] In some specific embodiments, the equipment used for molding can be the equipment commonly used for molding in the art, for example, a molding machine, which can be a double steel belt molding composite machine.

[0059] Preferably, the molding temperature is preferably 250-310℃, for example, 265℃.

[0060] In some specific embodiments, the molding method can be the conventional molding method in the art, for example, continuous molding or direct molding.

[0061] When the molding method is continuous molding, the steps including continuous automatic laying can be included according to the conventional method in the art, for example, including preheating for 1-7 min and pressure maintaining for 1-30 min. When the molding method is direct molding, the steps including preheating, exhaust, pressure maintaining, and cooling can be included according to the conventional method in the art.

[0062] In some specific embodiments, before the laying, the step of drying the material of each layer is preferably included. By drying to reduce the water content of the material, excessive bubbles can be prevented during the molding process.

[0063] The drying operation can be a conventional drying operation in the art, such as vacuum drying. The temperature of the drying is preferably 85-120℃, such as 105℃. The time of the drying is preferably 4-25h, further 15-24h, such as 15h, 20h, 24h.

[0064] Solution three: a shaped product comprising the bio-based polyamide composite sheet.

[0065] Solution four: use of the bio-based polyamide composite sheet in the field of aerospace, military, automotive materials, sports equipment, building materials or electronics.

[0066] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily, i.e. to obtain each preferred example of the present application. The reagents and raw materials used in the present application are commercially available.

[0067] The positive progress effect of the present application is that:

[0068] 1. The present application uses bio-based polyamide as raw material: the monomer pentanediamine in the raw material is prepared by biological fermentation, has high bio-based content, meets the concept of sustainable development of material source, has high bio-based content, effectively reduces the use of fossil raw materials, and thus reduces carbon emissions.

[0069] 2. The bio-based polyamide composite sheet of the present application: high fiber content, which can be higher than 60%; excellent mechanical properties, excellent heat resistance, and water absorption less than 0.3%, which can be applied to more extensive occasions; uniform fiber distribution, no fiber exposure, easy to process; the thickness of the composite material can be set between 2-40mm according to the needs, which can provide more design freedom for products; the final shaped product comprising the bio-based polyamide composite sheet of the present application can be recycled and reused, and has high resource utilization rate.

[0070] 3. The preparation method of the bio-based polyamide composite sheet of the present application is simple and feasible. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 It is a schematic diagram of the bio-based polyamide composite sheet in Example 1 of the present application, wherein: 1-first surface layer PA510 unidirectional prepreg tape; 2-intermediate layer PA56 silk glass fiber blended fabric; 3-intermediate layer three right diagonal glass fiber cloth. DETAILED DESCRIPTION

[0072] The present application will be further described by way of examples, but the present application is not limited to the scope of the examples. The experimental methods in the following examples are not specified, which are selected according to conventional methods and conditions, or according to the instructions of the goods.

[0073] In the following examples and comparative examples: each raw material is purchased from the following sources: PA510 and PA512 are both purchased from Kaisy (Jinxiang) Biomatierials Co., Ltd.; antioxidant is purchased from BASF Group, Germany; WAXE and WAXC are purchased from Clariant, Germany; compatibilizer is purchased from Shanghai Jiaiyi Polymer Co., Ltd.; coupling agent is purchased from Hangzhou Jessica Chemical Co., Ltd.; continuous long glass fiber is purchased from China Jushi, with a specification of 1200 Tex; three-ply right twill glass fiber cloth (brand EWR400) is purchased from China Jushi. The molding press used for molding is a double-steel-belt molding compound machine (mold width is 40 mm).

[0074] Among them, the properties of each polyamide resin are as follows:

[0075] The viscosity of PA510 is 2.51, the terminal amino group content is 54 mmol / kg, and the melting point is 217℃;

[0076] The viscosity of PA512 is 2.32, the terminal amino group content is 56 mmol / kg, and the melting point is 210℃.

[0077] Preparation of PA510 unidirectional prepreg tape as shown in Preparation Example 3 of the specification of the invention patent CN113232384A

[0078] Preparation of PA512 unidirectional prepreg tape as shown in Preparation Example 3 of the specification of the invention patent CN113232384A

[0079] Preparation of biobased PA56 filament glass fiber blended cloth

[0080] PA56 filaments (1200 dtex / 1100 f) with a breaking strength of 4.7 cN / dtex, an elongation at break of 59.1%, and a dry heat shrinkage of 8.2% were prepared according to the embodiment seven of the Chinese invention patent CN 110373736 A. The PA56 filaments and continuous long glass fibers (1200 tex) were twisted into PA56 / glass fiber hybrid filaments (2400 tex) by a twisting machine; then the hybrid filaments were bi-directionally blended by a rapier loom, and the warp and weft of the rapier loom were both PA56 / glass fiber hybrid filaments (2400 tex), the weaving process parameters were as follows: the speed of the loom was 300 r / min; the height of the back rest was 1050 mm, the height of the drop was 70 mm, and the distance between the front and back was 140 mm; the flat time was 320 s, and the hybrid fabric unit was woven by the warp and weft of the PA56 / glass fiber hybrid filaments in a cross shape, thereby obtaining a PA56 filament and glass fiber blended fabric, the average tensile strength in the warp and weft directions was 340.3 Mpa, the tensile modulus was 18.9 GPa, the tensile strain was 2.5%, and the moisture content was 0.79%. The tensile strength, the tensile modulus, and the tensile strain of the blended fabric were tested according to the standard GB / T 7689.5-2013, and the moisture content was tested according to the standard GB / T-9914.1.

[0081] Preparation of the PA6 filament and glass fiber blended fabric of comparative preparation example 1

[0082] Commercial PA6 filaments with a breaking strength of 7.5 cN / dtex, an elongation at break of 21.4%, and a boiling water shrinkage of 9.0% were used. The PA6 filaments and continuous long glass fibers (1200 tex) were twisted into PA6 / glass fiber hybrid filaments (2400 tex) by a twisting machine; then the hybrid filaments were bi-directionally blended by a rapier loom, and the warp and weft of the rapier loom were both PA56 / glass fiber hybrid filaments (2400 tex), the weaving process parameters were the same as those of preparation example 3, and the hybrid fabric unit was woven by the warp and weft of the PA6 / glass fiber hybrid filaments in a cross shape, thereby obtaining a PA6 filament and glass fiber blended fabric, the average tensile strength in the warp and weft directions was 318.9 Mpa, the tensile modulus was 16.3 GPa, the tensile strain was 3.0%, and the moisture content was 1.01%. The tensile strength, the tensile modulus, and the tensile strain of the blended fabric were tested according to the standard GB / T 7689.5-2013, and the moisture content was tested according to the standard GB / T-9914.1.

[0083] Biobased polyamide composite board of embodiment 1

[0084] The first surface layer was a PA510 unidirectional prepreg tape (the preparation method was as described in preparation example 1), the thickness was 0.31 mm, and the fiber content was 62.8 wt%;

[0085] The middle layer was a PA56 filament and glass fiber blended fabric (the preparation method was as described in preparation example 3); three pieces of right bias glass fiber cloth, the thickness was 0.175 mm;

[0086] Second skin layer: PA510 unidirectional prepreg tape (preparation method as in Preparation Example 1), thickness of 0.31 mm, fiber content of 62.8 wt%;

[0087] The prepreg tape, blended fabric, and glass fabric were cut into the size of the mold, a layer of release cloth was placed on the upper and lower layers of the mold plate, and different numbers of first skin layer, intermediate layer, and second skin layer were placed in the middle. Continuous molding was performed on a double steel belt molding composite machine, specifically:

[0088] (1) The first skin layer was laid 1 layer, i.e., PA510 unidirectional prepreg tape;

[0089] (2) The intermediate layer was laid a total of 15 layers, with PA56 silk glass fiber blended fabric layers on the upper and lower layers, and PA56 silk glass fiber blended fabric and three pieces of right bias glass fabric layers alternately laid in the middle. PA56 silk glass fiber blended fabric was laid a total of 8 layers, and three pieces of right bias glass fabric were laid a total of 7 layers, i.e., PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric-glass fabric-PA56 silk glass fiber blended fabric;

[0090] (3) The second skin layer was laid 1 layer, i.e., PA510 unidirectional prepreg tape;

[0091] The molding machine temperature was set to 265°C, and the molding machine pressure was controlled at 2 MPa. A bio-based polyamide composite board with a thickness of 2 mm and 17 layers was prepared. The schematic diagram of the bio-based polyamide composite board prepared in this example is shown in Figure 1 .

[0092] Bio-based polyamide composite board of Example 2

[0093] First skin layer: PA512 unidirectional prepreg tape (preparation method as in Preparation Example 2), thickness of 0.31 mm, fiber content of 61.8 wt%;

[0094] Intermediate layer: PA56 silk glass fiber blended fabric (preparation method as in Preparation Example 3); three pieces of right bias glass fabric, thickness of 0.175 mm;

[0095] Second skin layer: PA512 unidirectional prepreg tape (preparation method as in Preparation Example 2), thickness of 0.31 mm, fiber content of 61.8 wt%;

[0096] The prepreg, blended fabric and glass fiber fabric are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of first surface layer, intermediate layer and second surface layer are placed in the middle, and continuous molding is carried out on the double steel belt molding compound machine, specifically:

[0097] (1) The first surface layer is laid in 1 layer, that is, PA512 unidirectional prepreg;

[0098] (2) The intermediate layer is laid in 15 layers, the upper and lower layers of which are PA56 silk glass fiber blended fabric layers, and the middle is PA56 silk glass fiber blended fabric and three pieces of right bias glass fiber fabric laid alternately, 8 layers of PA56 silk glass fiber blended fabric and 7 layers of three pieces of right bias glass fiber fabric, that is, PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric;

[0099] (3) The second surface layer is laid in 1 layer, that is, PA512 unidirectional prepreg;

[0100] The temperature of the molding machine is set to 265 DEG C, and the pressure of the molding machine is controlled at 2 MPa, and a bio-based polyamide composite plate with a thickness of 2 mm and 17 layers is prepared.

[0101] Example 3 bio-based polyamide composite plate

[0102] The first surface layer, the second surface layer and the intermediate layer are the same as in Example 1, except that the first surface layer and the third surface layer are respectively laid by two layers of prepreg.

[0103] The prepreg, blended fabric and glass fiber fabric are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of first surface layer, intermediate layer and second surface layer are placed in the middle, and continuous molding is carried out on the double steel belt molding compound machine, specifically:

[0104] (1) The first surface layer is laid in 2 layers, and the two layers of PA510 unidirectional prepreg are laid in 0° / 90° cross-laying;

[0105] (2) The intermediate layer is laid in 9 layers, the upper and lower layers of which are PA56 silk glass fiber blended fabric layers, and the middle is PA56 silk glass fiber blended fabric and three pieces of right bias glass fiber fabric laid alternately, and 5 layers of PA56 silk are laid, and 4 layers of three pieces of right bias glass fiber fabric, that is, PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric-glass fiber fabric-PA56 silk glass fiber blended fabric;

[0106] (3) The second surface layer is laid with 2 layers of PA510 unidirectional prepreg tape in 0° / 90° cross-laying;

[0107] The temperature of the molding machine was set to 265°C, and the pressure of the molding machine was controlled at 2 MPa to prepare a bio-based polyamide composite board with a thickness of 2 mm and 13 layers.

[0108] Example 4 Bio-based polyamide composite board

[0109] The first surface layer, the second surface layer, and the intermediate layer have the same raw materials as in Example 2, except that the first surface layer and the third surface layer are respectively laid with two layers of prepreg tape in cross-laying.

[0110] The prepreg tape, the blended fabric, and the twill glass fiber cloth were cut to the size of the mold, one layer of release cloth was placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the intermediate layer, and the second surface layer were placed in the middle. Continuous molding was performed on a double-steel-belt molding composite machine, specifically:

[0111] (4) The first surface layer is laid with 2 layers of PA512 unidirectional prepreg tape in 0° / 90° cross-laying;

[0112] (5) The intermediate layer is laid with a total of 9 layers, of which the upper and lower layers are PA56 silk glass fiber blended fabric layers, and the middle is PA56 silk glass fiber blended fabric and three layers of right twill glass fiber cloth laid alternately, with a total of 5 layers of PA56 silk and 4 layers of three layers of right twill glass fiber cloth, i.e. PA56 silk glass fiber blended fabric-glass fiber cloth-PA56 silk glass fiber blended fabric-glass fiber cloth-PA56 silk glass fiber blended fabric-glass fiber cloth-PA56 silk glass fiber blended fabric-glass fiber cloth-PA56 silk glass fiber blended fabric;

[0113] (6) The second surface layer is laid with 2 layers of PA512 unidirectional prepreg tape in 0° / 90° cross-laying;

[0114] The temperature of the molding machine was set to 265°C, and the pressure of the molding machine was controlled at 2 MPa to prepare a bio-based polyamide composite board with a thickness of 2 mm and 13 layers.

[0115] Example 5 Bio-based polyamide composite board

[0116] The first surface layer, the second surface layer, and the intermediate layer have the same raw materials as in Example 1, except that the laying method is different: the prepreg tape, the blended fabric, and the glass fiber cloth were cut to the size of the mold, one layer of release cloth was placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the intermediate layer, and the second surface layer were placed in the middle. Continuous molding was performed on a double-steel-belt molding composite machine, specifically:

[0117] (1) The first surface layer is laid with 1 layer, i.e. PA510 unidirectional prepreg tape;

[0118] (2) the middle layer is 31 layers of PA56 silk glass fiber mixed fabric layers, the upper and lower layers are PA56 silk glass fiber mixed fabric layers, and the middle is 16 layers of PA56 silk glass fiber mixed fabric and 15 layers of three right diagonal glass fiber cloth layers which are alternately laid up;

[0119] (3) the second surface layer is 1 layer of PA510 unidirectional prepreg tape;

[0120] The temperature of the molding machine is set to 270°C, and the pressure of the molding machine is controlled at 3 MPa, thereby preparing a bio-based polyamide composite board with a thickness of 4 mm and 33 layers.

[0121] Example 6: Bio-based polyamide composite board

[0122] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 2, except that the laying method is different: the prepreg tape, the mixed fabric, and the glass fiber cloth are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the middle layer, and the second surface layer are placed in the middle, and then continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0123] (1) the first surface layer is 1 layer of PA512 unidirectional prepreg tape;

[0124] (2) the middle layer is 31 layers of PA56 silk glass fiber mixed fabric layers, the upper and lower layers are PA56 silk glass fiber mixed fabric layers, and the middle is 16 layers of PA56 silk glass fiber mixed fabric and 15 layers of three right diagonal glass fiber cloth layers which are alternately laid up;

[0125] (3) the second surface layer is 1 layer of PA512 unidirectional prepreg tape;

[0126] The temperature of the molding machine is set to 270°C, and the pressure of the molding machine is controlled at 3 MPa, thereby preparing a bio-based polyamide composite board with a thickness of 4 mm and 33 layers.

[0127] Example 7: Bio-based polyamide composite board

[0128] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 1, except that the laying method is different: the prepreg tape, the mixed fabric, and the glass fiber cloth are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the middle layer, and the second surface layer are placed in the middle, and then continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0129] (1) the first surface layer is 2 layers of PA510 unidirectional prepreg tape which are laid in a 0° / 90° cross pattern;

[0130] (2) the middle layer is 25 layers of PA56 silk glass fiber blended fabric layers, the upper and lower layers are 13 layers of PA56 silk glass fiber blended fabric layers and 13 layers of three right diagonal glass fiber cloth layers alternately arranged;

[0131] (3) the second surface layer is 2 layers of PA510 unidirectional prepreg tape layers arranged in 0° / 90° cross-ply;

[0132] The temperature of the molding machine is set to 270°C, and the pressure of the molding machine is controlled at 3 MPa, thereby preparing a bio-based polyamide composite board with a thickness of 4 mm and 29 layers.

[0133] Example 8 bio-based polyamide composite board

[0134] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 2, except that the layer arrangement is different: the prepreg tape, the blended fabric, and the glass fiber cloth are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the middle layer, and the second surface layer are placed in the middle, and then continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0135] (4) the first surface layer is 2 layers of PA512 unidirectional prepreg tape layers arranged in 0° / 90° cross-ply;

[0136] (5) the middle layer is 25 layers of PA56 silk glass fiber blended fabric layers, the upper and lower layers are 13 layers of PA56 silk glass fiber blended fabric layers and 13 layers of three right diagonal glass fiber cloth layers alternately arranged;

[0137] (6) the second surface layer is 2 layers of PA512 unidirectional prepreg tape layers arranged in 0° / 90° cross-ply;

[0138] The temperature of the molding machine is set to 270°C, and the pressure of the molding machine is controlled at 3 MPa, thereby preparing a bio-based polyamide composite board with a thickness of 4 mm and 29 layers.

[0139] Comparative Example 1 polyamide 6 composite board

[0140] The first surface layer and the first surface layer have the same raw materials as in Example 1, except that the middle layer is PA6 silk glass fiber blended fabric (preparation method as in Comparative Preparation Example 1); three right diagonal glass fiber cloth with a thickness of 0.175 mm;

[0141] The prepreg tape, the blended fabric, and the glass fiber cloth are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold plate, and different numbers of the first surface layer, the middle layer, and the second surface layer are placed in the middle, and then continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0142] (1) The first surface layer is laid with 1 layer, i.e. PA510 unidirectional prepreg tape;

[0143] (2) The middle layer is laid with 15 layers, the upper and lower surface layers of which are PA6 silk layers, and the middle is alternately laid with PA6 silk fiberglass blended fabric and three right diagonal fiberglass cloth layers, and the PA6 silk fiberglass blended fabric is laid with 8 layers and the three right diagonal fiberglass cloth is laid with 7 layers, i.e. PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric;

[0144] (3) The second surface layer is laid with 1 layer, i.e. PA510 unidirectional prepreg tape;

[0145] The temperature of the molding machine is set to 240°C, and the pressure of the molding machine is controlled at 2 MPa, thereby preparing a polyamide 6 composite board with a thickness of 2 mm and 17 layers.

[0146] Comparative polyamide 6 composite board 2

[0147] The first surface layer and the raw material of the first surface layer are the same as those of Example 2, and the difference lies in that the middle layer is PA6 silk fiberglass blended fabric (preparation method as in Comparative Preparation Example 1); three right diagonal fiberglass cloth, thickness is 0.175 mm;

[0148] The prepreg tape, blended fabric and fiberglass cloth are cut into the size of the mold, a layer of release cloth is placed on the upper and lower layers of the mold, and different layers of the first surface layer, the middle layer and the second surface layer are placed in the middle, and then continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0149] (1) The first surface layer is laid with 1 layer, i.e. PA512 unidirectional prepreg tape;

[0150] (2) The middle layer is laid with 15 layers, the upper and lower surface layers of which are PA6 silk layers, and the middle is alternately laid with PA6 silk fiberglass blended fabric and three right diagonal fiberglass cloth layers, and the PA6 silk fiberglass blended fabric is laid with 8 layers and the three right diagonal fiberglass cloth is laid with 7 layers, i.e. PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric-glass fiber cloth-PA6 silk fiberglass blended fabric;

[0151] (3) The second surface layer is laid with 1 layer, i.e. PA512 unidirectional prepreg tape;

[0152] The temperature of the molding machine was set to 240°C, and the pressure of the molding machine was controlled at 2 MPa, to prepare a polyamide 6 composite board with a thickness of 2 mm and 17 layers.

[0153] Comparative Example 3: Polyamide 6 composite board

[0154] The first surface layer and the raw material of the first surface layer were the same as in Example 1, except that the intermediate layer was PA6 silk glass fiber blended fabric (preparation method as in Comparative Preparation Example 1); three right diagonal glass fiber cloth, thickness of 0.175 mm;

[0155] The prepreg, blended fabric and glass fiber cloth were cut to the size of the mold, and a layer of release cloth was placed on the upper and lower layers of the mold plate, and different numbers of first surface layers, intermediate layers and second surface layers were placed in the middle. Continuous molding was performed on a double steel belt molding composite machine, specifically:

[0156] (1) The first surface layer was laid 1 layer, PA510 unidirectional prepreg;

[0157] (2) The intermediate layer was laid 31 layers in total, with PA6 silk glass fiber blended fabric layers on the upper and lower layers, and PA6 silk glass fiber blended fabric and three right diagonal glass fiber cloth layers alternately laid on the upper and lower layers, with 16 layers of PA6 silk and 15 layers of three right diagonal glass fiber cloth;

[0158] (3) The second surface layer was laid 1 layer, PA510 unidirectional prepreg;

[0159] The temperature of the molding machine was set to 240°C, and the pressure of the molding machine was controlled at 2 MPa, to prepare a polyamide 6 composite board with a thickness of 4 mm and 33 layers.

[0160] Comparative Example 4: Polyamide 6 composite board

[0161] The first surface layer and the raw material of the first surface layer were the same as in Example 1, except that the intermediate layer was PA6 silk glass fiber blended fabric (preparation method as in Comparative Preparation Example 1); three right diagonal glass fiber cloth, thickness of 0.175 mm;

[0162] The prepreg, blended fabric and glass fiber cloth were cut to the size of the mold, and a layer of release cloth was placed on the upper and lower layers of the mold plate, and different numbers of first surface layers, intermediate layers and second surface layers were placed in the middle. Continuous molding was performed on a double steel belt molding composite machine, specifically:

[0163] (1) The first surface layer was laid 2 layers, i.e. two layers of PA510 unidirectional prepreg were laid at 90°;

[0164] (2) The intermediate layer was laid 25 layers in total, with PA6 silk glass fiber blended fabric layers on the upper and lower layers, and PA6 silk glass fiber blended fabric and three right diagonal glass fiber cloth layers alternately laid on the upper and lower layers, with 13 layers of PA6 silk glass fiber blended fabric and 12 layers of three right diagonal glass fiber cloth;

[0165] (3) The second surface layer is laid 2 layers, i.e. two layers of PA510 unidirectional prepreg tape are laid in a 90° layer;

[0166] The temperature of the molding machine is set to 240℃, and the pressure of the molding machine is controlled at 2MPa, to prepare a polyamide 6 composite board material with a thickness of 4mm and 29 layers.

[0167] The composite board material prepared in the above examples and comparative examples is tested according to the following standards:

[0168] 1. Bending strength and bending modulus: according to the standard ASTM D790-2017, the composite board material sample is cut into a sample with a size of 127mm long, 12.7mm wide and 2mm thick for testing;

[0169] 2. Heat distortion temperature (HDT) test: according to the national standard GB / T 1634.2-2004, a sample with a size of 120mm long, 10mm wide and 4mm thick is prepared, and a bending stress of 1.8Mpa is applied.

[0170] 3. Water absorption test: according to the standard ASTM-D570-2005, a sample with a size of 60mm long, 60mm wide and 2mm thick is prepared, and the test time is 24h according to the plastic method.

[0171] 4. Fiber content test of the composite board material: according to the national standard GB / T 9345.1-2008, calcination is carried out at a high temperature of 700℃ for 2 hours.

[0172] Table 1

[0173]

[0174] As can be seen from Table 1: by comparing the examples with the comparative examples, it can be found that the mechanical strength and modulus of the bio-based polyamide composite board material of the present application are obviously improved compared with the corresponding properties of the PA6 composite board material, the heat resistance is also significantly better than that of the PA6 composite board material, and the water absorption is lower than that of the PA6 composite board material.

Claims

1. A bio-based polyamide composite panel, characterized in that, It comprises a first surface layer, an intermediate layer and a second surface layer; the first surface layer, the intermediate layer and the second surface layer are stacked in turn; the first surface layer and the second surface layer are long carbon chain polyamide resin unidirectional prepreg tapes, and the intermediate layer is a composite layer of bio-based polyamide 56 filament glass fiber blended fabric and fiber cloth; The long carbon chain polyamide resin unidirectional prepreg tape is a continuous long fiber reinforced long carbon chain polyamide resin unidirectional prepreg tape, which comprises continuous long fibers and bio-based long carbon chain polyamide 5X resin, and the bio-based long carbon chain polyamide 5X resin is selected from one or more of PA510, PA511, PA512, PA513, PA514, PA515, PA516, PA517 and PA518; The fiber cloth comprises any one or more of woven cloth, unidirectional cloth, bidirectional prepreg cloth or multi-axial cloth made of carbon fiber, glass fiber, basalt fiber or aramid fiber.

2. The bio-based polyamide composite panel according to claim 1, characterized in that, The mass percentage of the continuous long fiber is 40-80%; and / or, The bio-based long carbon chain polyamide 5X resin has a relative viscosity of 1.8-3.2, an amino end group content of 42-60 mmol / kg, a melting point of 170-320°C, and a bio-based content of 28-100%; and / or, The continuous long fiber comprises carbon fiber, glass fiber, basalt fiber or aramid fiber; and / or, The fiber cloth comprises unidirectional prepreg cloth made of carbon fiber, glass fiber, basalt fiber or aramid fiber.

3. The bio-based polyamide composite panel according to claim 1, characterized in that, The mass percentage of the continuous long fiber is 60-70%; and / or, The bio-based long carbon chain polyamide 5X resin has a relative viscosity of 2.1-2.8; and / or, The bio-based long carbon chain polyamide 5X resin has a melting point of 180-230°C; and / or, The continuous long fiber is continuous long glass fiber or continuous long carbon fiber.

4. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the long carbon chain polyamide resin unidirectional prepreg tape is 0.15-0.5 mm.

5. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the long carbon chain polyamide resin unidirectional prepreg tape is 0.21-0.33 mm.

6. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the long carbon chain polyamide resin unidirectional prepreg tape is 0.31 mm, 0.32 mm or 0.33 mm.

7. The bio-based polyamide composite panel of claim 1, wherein, The bio-based polyamide 56 filament glass fiber blended fabric is made by blending bio-based polyamide 56 filament / glass fiber mixed yarns; the bio-based polyamide 56 filament / glass fiber mixed yarns are made by mixing bio-based polyamide 56 filament and glass fiber, and the mass ratio of the bio-based polyamide 56 filament to the glass fiber is 1:0.15-4; and / or, The bio-based polyamide 56 filament glass fiber blended fabric has a tensile strength of more than 300 MPa, a tensile modulus of more than 13 GPa, a tensile strain of less than 5%, and a moisture content of less than 1.5%.

8. The bio-based polyamide composite panel according to claim 7, characterized in that, The warp and weft yarns of the bio-based polyamide 56 filament glass fiber blended fabric are both bio-based polyamide 56 filament / glass fiber mixed yarns; and / or, The warp and weft yarns of the bio-based polyamide 56 filament glass fiber blended fabric are crosswise interlaced; and / or, The bio-based polyamide 56 filament glass fiber blended fabric has a tensile modulus of more than 16 GPa.

9. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the fiber cloth is 0.1-0.4 mm.

10. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the fiber cloth is 0.175-0.193 mm.

11. The bio-based polyamide composite panel according to claim 1, characterized in that, The thickness of the fiber cloth is 0.185 mm.

12. The bio-based polyamide composite panel of claim 1, wherein, The intermediate layer is an alternately layered bio-based polyamide 56 filament glass fiber blended cloth and fiber cloth; The number of layers of the intermediate layer is more than 3.

13. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the bio-based polyamide composite board is more than 0.5 mm; and / or, The total number of layers of the first surface layer, the intermediate layer and the second surface layer is more than 5.

14. The bio-based polyamide composite panel of claim 1, wherein, The thickness of the bio-based polyamide composite board is 2-40 mm.

15. A method for producing the bio-based polyamide composite board according to any one of claims 1 to 14, characterized by, The first surface layer, the intermediate layer and the second surface layer are sequentially layered and then subjected to mold pressing forming, the temperature of the mold pressing forming is 170-310 ℃, and the pressure of the mold pressing forming is 0-5 MPa.

16. The method of claim 15, wherein, The mold pressing forming is continuous mold pressing forming or direct mold pressing forming; and / or, The pressure of the mold pressing forming is 2 MPa.

17. A molded product comprising the bio-based polyamide composite board according to any one of claims 1-14.

18. Use of the bio-based polyamide composite board according to any one of claims 1-14 in the fields of aerospace, military, automobile materials, sports equipment, building materials or electronics.

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