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 board and its preparation method and application.Bio-based polyamide composite board 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 includes bio-based polyamide film and fiber cloth.The composite board compression molding guarantees that the processing rate of plate and efficient forming are improved, the mechanical properties and thermal deformation temperature of composite board are improved, the water absorption of composite board is reduced, and the overall quality is light, more meet the demand of lightweight plate.

Description

[0001] The present application claims priority from Chinese Patent Application No. 202110854375.4, filed on July 28, 2021, and entitled "A Bio-based Polyamide Composite Board and Its Preparation Method and Application", and Chinese Patent Application No. 202121728585.0, filed on July 28, 2021, and entitled "A Bio-based Polyamide Composite Board". The present application incorporates the entire contents 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 have played an important role in many fields and have replaced many traditional materials. The main composite material forming processes include winding forming, laying forming, mold pressing forming, autoclave forming, and resin transfer molding, etc. Composite material forming process usually includes two stages, first, making the raw material deform or flow under certain temperature and pressure to obtain the required shape, and then trying to maintain its shape. 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.

[0004] The composite material prepared by mold pressing forming is applied in various fields. The existing thermosetting composite board is prepared by curing with epoxy resin, which has a long curing time, low glass fiber content, and the composite board cannot be recycled. The ordinary thermoplastic material composite board also has water absorption, high strength, and low characteristics. Therefore, in order to make the polyamide composite board 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. SUMMARY

[0005] In order to improve the performance of the existing polyamide composite board and broaden the use scenarios, the present application provides a bio-based polyamide composite board and its preparation method and application. The bio-based polyamide composite board of the present application is mold pressed by bio-based polyamide film, fiber cloth and bio-based polyamide unidirectional prepreg tape, which ensures 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, which better meets the demand of lightweight board.

[0006] 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 bio-based content detection standard method ASTM D6866.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] One of the technical solutions: a bio-based polyamide composite board, comprising a first surface layer, a middle layer and a second surface layer; the first surface layer, the middle 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 tape, and the middle layer comprises a bio-based polyamide film and a fiber cloth.

[0009] Long carbon chain polyamide resin unidirectional prepreg tape:

[0010] 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 referring to the mass of the continuous long fibers accounting for the mass of the prepreg tape.

[0011] 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 bio-based long carbon chain polyamide 5X resin has a relative viscosity of 1.8-2.7, preferably 2.1-2.6; an end amino group content of 42-60 mmol / kg; a melting point of 170℃-320℃, preferably 180-230℃; and a bio-based content of 28%-100%.

[0012] In some specific embodiments, the continuous long fibers can be conventional commercially available continuous long fibers in the art, and the types can be conventional in the art, such as carbon fibers, glass fibers, basalt fibers or aramid fibers.

[0013] In some specific embodiments, the continuous long fibers are continuous long glass fibers, and the monofilament diameter can be 8-15μm, more preferably 8-10μm. The linear density of the continuous long glass fibers can be 1000-3600Tex, more preferably 1200Tex, 2400Tex. Alternatively, the monofilament diameter can be 8-25μm, more preferably 15-20μm. The linear density of the continuous long glass fibers can be 500-3600Tex, more preferably 1200Tex, 2400Tex. The continuous long glass fibers are, for example, continuous long glass fibers with a specification of 1200Tex purchased from Owens Corning (OC) or continuous long glass fibers with a specification of 2400Tex purchased from Giant Stone.

[0014] In some specific embodiments, the continuous long fibers are continuous long carbon fibers. The continuous long carbon fibers are preferably polyacrylonitrile-based carbon fibers. The number of filaments of the continuous long carbon fibers can be 20,000-30,000, preferably 12,000 (12K), 24,000 (24K); or, the number of filaments of the continuous long carbon fibers can be 5,000-60,000, preferably 12,000 (12K), 24,000 (24K), 48,000 (48K). The diameter of the filaments of the continuous long carbon fibers can be 5-10 μm, preferably 6-8 μm. The continuous long carbon fibers are, for example, Toray T700 with a specification of 24K, or Guangwei composite continuous long carbon fiber 700S with a specification of 12K or 24K.

[0015] 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.

[0016] In some specific embodiments, the melt impregnation method comprises the following steps:

[0017] S1, stirring and mixing a long carbon chain polyamide 5X resin-containing long carbon chain polyamide resin composition, extruding by a twin-screw extruder (preferably with a length-diameter ratio of 1:36), the temperature of extrusion can be 170-340°C, filtering by a melt filter, and feeding the melt into an impregnation die; preferably, the twin-screw extruder adopts an eight-zone heating mode, and the temperature of the first zone to the eighth zone (from feeding to the die head) is 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.

[0018] S2, introducing the continuous long fibers into the impregnation die, and impregnating the melt and the continuous long fibers; the temperature of the impregnation die can be 240-335°C; the introduction preferably comprises the following processes: the continuous long fibers are unwound from a creel through a yarn separator frame, enter a yarn spreading system to fully spread each filament bundle, then enter a yarn drying device for preheating, and then enter the impregnation die to impregnate the continuous long fibers with the melt, wherein the temperature of the yarn drying device is preferably 70-400°C;

[0019] S3, shaping, cooling, drawing, and winding the impregnated continuous long fibers to obtain the long carbon chain polyamide resin unidirectional prepreg tape;

[0020] In some specific embodiments, the setting and cooling can be performed by a four-roller machine as conventional in the art; the four-roller machine mainly comprises a setting roller and a cooling roller; the temperature of the internal circulating oil in the setting roller can be 30-250°C, for example, 90°C, 120°C, 150°C, or 180°C; the temperature of the internal circulating water in the cooling roller can be 15-90°C, for example, 20°C, 40°C, 60°C, or 80°C. The setting roller functions to secondary infiltration and cooling molding, and the cooling roller functions to cooling molding. The pulling can be performed by a pulling device as conventional in the art, in which further cooling and edge cutting are performed. The speed of the pulling can be 5-15 m / min. The winding can be performed by a winding device as conventional in the art, preferably an automatic winding machine; the speed of the winding can be 5-15 m / min.

[0021] In some specific embodiments, the long carbon chain polyamide resin composition comprises the following components in parts 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. The antioxidant is preferably selected from one or more of antioxidant 168, antioxidant 1098, antioxidant 1010, and antioxidant S9228. The lubricant comprises WAXC and WAXE. The compatibilizer can be selected from one or more of PP-g-MAH, POE-g-MAH, POE-g-GMA, or EPDM-g-MAH. The coupling agent can be selected from one or more of coupling agent KH550, coupling agent KH560, or coupling agent KH570.

[0022] In a specific embodiment, the long carbon chain polyamide resin composition comprises the following components in parts by weight: long carbon chain bio-based polyamide PA510: 94.5 parts, antioxidant 1098: 0.3 parts, antioxidant 168: 0.3 parts, internal lubricant WAXE: 0.2 parts, external lubricant WAXC: 0.2 parts, compatibilizer POE-g-MAH: 4 parts, coupling agent KH550: 0.5 parts.

[0023] In a specific embodiment, the long carbon chain polyamide resin composition comprises the following components in parts by weight: long carbon chain bio-based polyamide PA512: 94.5 parts, antioxidant 1098: 0.3 parts, antioxidant 168: 0.3 parts, internal lubricant WAXE: 0.2 parts, external lubricant WAXC: 0.2 parts, compatibilizer POE-g-MAH: 4 parts, coupling agent KH550: 0.5 parts.

[0024] 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.

[0025] In some specific embodiments, the continuous long fiber reinforced 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.

[0026] In some specific embodiments, the continuous long fiber reinforced 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 paragraphs

[0008] and

[0052] -

[0053] of patent CN113232384A.

[0027] Bio-based polyamide film:

[0028] In some specific embodiments, the bio-based polyamide film has a thickness of 0.01-5 mm, for example 0.15 mm.

[0029] In some specific embodiments, the bio-based polyamide film is obtained by casting a bio-based polyamide resin / melt. The bio-based polyamide is selected from one or more of PA56, PA510, PA511, PA512, PA513, PA514, PA515, and PA516.

[0030] In some specific embodiments, the bio-based polyamide film can be obtained by screw extruding a bio-based polyamide resin at 220-300 °C to obtain a molten polyamide, extruding the molten polyamide through a casting die to obtain a molten film, and then cooling and setting the molten film through a cooling roller and a cooling roller, winding, and slitting. The cooling roller temperature is 20-40 °C, for example 30 °C. Specifically, the thickness deviation of the film can be controlled within ±2% by automatically adjusting the die lip opening through online thickness detection and feedback to obtain films of different thicknesses.

[0031] In some specific embodiments, the bio-based polyamide resin is PA56, which has a relative viscosity of 2.29, an end amino group content of 55 mmol / kg, a melting point of 253 °C, a bio-based content of 45%, and a water content of ≤2000 ppm.

[0032] In some specific embodiments, the bio-based polyamide resin is PA510 with a relative viscosity of 2.51, an amino end group content of 54 mmol / kg, a melting point of 217℃, a bio-based content of 100%, and a moisture content of ≤2000 ppm.

[0033] In some specific embodiments, the bio-based polyamide film can be a nylon 56 film, for example, the nylon film disclosed in paragraphs

[0008] -

[0013] of patent CN103146190A.

[0034] In some specific embodiments, the bio-based polyamide film can be a polyamide 56 resin film, for example, the polyamide 56 resin film disclosed in paragraph

[0007] of patent CN111763313A.

[0035] Fiber cloth:

[0036] In some specific embodiments, the fiber cloth includes any one or more of woven cloth, unidirectional cloth, unidirectional prepreg cloth, bidirectional prepreg cloth, or multi-axial cloth made of carbon fiber, glass fiber, basalt fiber, or aramid fiber.

[0037] In some specific embodiments, the fiber cloth is a glass fiber cloth, for example, a plain weave glass fiber cloth or a twill weave glass fiber cloth, such as commercially available EWR400 or EWR500T3 from China Giant Stone Co., Ltd.

[0038] In some specific embodiments, the fiber cloth has a thickness of 0.1-0.4 mm, preferably 0.175-0.193 mm. For example, a plain weave glass fiber cloth with a thickness of 0.175 mm or a twill weave glass fiber cloth with a thickness of 0.185 mm.

[0039] In the present application, the layering manner between the first surface layer, the intermediate layer, and the second surface layer can be parallel layering or cross layering. The parallel layering refers to the same layering direction between layers, and the cross layering refers to a certain angle between layers. The angle of the cross layering can be 0°-90° cross, for example, 45° cross or 90° cross.

[0040] In some specific embodiments, the bio-based polyamide film and the fiber cloth of the intermediate layer are alternately layered.

[0041] In some specific embodiments, the number of layers of the first surface layer and the second surface layer is respectively 1 layer or more, which can also be 2 layers, 3 layers, 4 layers, or more. For example, the first surface layer and the second surface layer each layer 1 layer of long carbon chain polyamide resin unidirectional prepreg tape, or are cross-layered with 2 layers of long carbon chain polyamide resin unidirectional prepreg tape, respectively.

[0042] In some specific embodiments, the number of layers of the intermediate layer is more than 2, for example, it can be 3, 4 or more. For example, when the number of layers of the intermediate layer is 3, the biobased polyamide film and the fiber cloth are alternately laid, and each layer is respectively: biobased polyamide film-fiber cloth-biobased polyamide film. For example, when the number of layers of the intermediate layer is 4, the biobased polyamide film and the fiber cloth are alternately laid, and each layer is respectively: biobased polyamide film-fiber cloth-biobased polyamide film-fiber cloth.

[0043] In some specific embodiments, the total number of layers of the first surface layer, the intermediate layer and the second surface layer is 5-200, for example, 13, 25, 11. For example, when the total number of layers is 5, the biobased polyamide composite board is sequentially: long-chain carbon polyamide resin unidirectional prepreg tape-biobased polyamide film-fiber cloth-biobased polyamide film-long-chain carbon polyamide resin unidirectional prepreg tape from the first surface layer.

[0044] In some specific embodiments, different total number of layers can be set according to the thickness of the composite board for molding.

[0045] In some specific embodiments, the thickness of the biobased polyamide composite board is more than 0.5 mm.

[0046] In some specific embodiments, the thickness of the biobased polyamide composite board is 1-40 mm, for example, 2 mm, 4 mm, 10 mm.

[0047] Technical solution two: a biobased polyamide composite board A, comprising a biobased polyamide film and a fiber cloth, the biobased polyamide film and the fiber cloth are alternately laid.

[0048] Wherein, the biobased polyamide film can be as described above.

[0049] Wherein, the fiber cloth can be as described above.

[0050] Wherein, the number of layers of the biobased polyamide composite board A can be more than 2, for example, it can be 3, 4 or more. For example, when the number of layers of the biobased polyamide composite board A is 3, the biobased polyamide film and the fiber cloth are alternately laid, and each layer is respectively: biobased polyamide film-fiber cloth-biobased polyamide film. For example, when the number of layers of the biobased polyamide composite board A is 4, the biobased polyamide film and the fiber cloth are alternately laid, and each layer is respectively: biobased polyamide film-fiber cloth-biobased polyamide film-fiber cloth.

[0051] Technical solution three: a preparation method of a biobased polyamide composite board, the first surface layer, the intermediate layer and the second surface layer are sequentially laid and then molded, the temperature of the molding is 170-310℃, and the pressure is 0-5Mpa.

[0052] In the preparation process of the composite board, the bio-based polyamide film is melted at high temperature, impregnated with fiber cloth and / or long carbon chain polyamide resin prepreg, and then cooled and shaped to obtain the composite board.

[0053] In the present application, the equipment used for the compression molding can be the equipment commonly used in the field for compression molding, such as a compression molding machine, which can be a double steel belt compression molding machine.

[0054] In some specific embodiments, the temperature of the compression molding is preferably 5-10℃ higher than the melting point of the bio-based polyamide resin, preferably 225-265℃, for example 265℃.

[0055] In some specific embodiments, the pressure is 1-5Mpa, for example 2Mpa.

[0056] In some specific embodiments, the compression molding method can be the conventional compression molding method in the field, such as continuous compression molding or direct compression molding.

[0057] In some specific embodiments, when the compression molding method is continuous compression molding, the steps of continuous automatic layering in the field can be followed, for example, including preheating for 1-7min, pressure maintaining for 1-30min, preferably, preheating for 5-7min, pressure maintaining for 8-10min. When the compression molding method is direct compression molding, the direct compression molding can follow the steps of preheating, degassing, pressure maintaining, and cooling in the field.

[0058] In the present application, before the layering, the step of drying the material of each layer is preferably also included. Reducing the water content of the material through drying can prevent excessive bubbles from being generated during the compression process.

[0059] The drying operation can be the conventional drying operation in the field, such as vacuum drying. The drying temperature is preferably 85-120℃, for example 105℃. The drying time is preferably 4-25h, further 15-24h, for example 15h, 20h, 24h.

[0060] Technical solution four: a shaped product comprising the bio-based polyamide composite board.

[0061] Technical solution five: application of the bio-based polyamide composite board in the fields of aerospace, military, automotive materials, sports equipment, building materials, or electronics.

[0062] On the basis of common sense in the field, 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.

[0063] The positive progress effect of the present application is that:

[0064] 1、The bio-based polyamide composite board of 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, thereby reducing carbon emissions.

[0065] 2、The bio-based polyamide composite board of the present application has:

[0066] (1) High glass fiber content, which can be higher than 60%;

[0067] (2) Excellent mechanical properties, specifically, the bending strength of 2mm composite board is all above 295MPa, and the bending modulus is all above 13GPa; the bending strength of 4mm composite board is all above 376MPa, and the bending modulus is all above 13GPa; low water absorption, all below 0.64%; excellent heat resistance;

[0068] (3) Uniform fiber distribution, no fiber exposure, easy to process;

[0069] (4) The thickness of the board can be set between 1-40mm according to needs, which can provide more design freedom for products.

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

[0071] Figure 1 Figure 1 is a structural schematic diagram of the composite board of Example 1 of the present application, wherein: 1: PA510 unidirectional prepreg tape; 2: PA56 film; 3: plain glass fiber cloth; 4: PA510 unidirectional prepreg tape. DETAILED DESCRIPTION

[0072] The present application will be further described by way of examples, but the present application is not limited in the scope of the examples. The experimental methods in the following examples without specific conditions are selected according to conventional methods and conditions, or according to the instructions of the commodity.

[0073] In the following examples and comparative examples: the purchase sources of each raw material are as follows: bio-based polyamide resin PA56, PA510, PA512, purchased from Kaisy (Jinxiang) Biomatierials Co., Ltd.; antioxidant purchased from BASF Group in Germany; WAXE and WAXC purchased from Clariant in Germany; compatibilizer purchased from Shanghai Jiaiyi Polymer Co., Ltd.; coupling agent purchased from Hangzhou Jessica Chemical Co., Ltd.; continuous long glass fiber purchased from Owens Corning (OC), with a specification of 1200 Tex; plain weave glass fiber cloth (brand EWR400), twill weave glass fiber cloth (brand EWR500T3), purchased from China Jushi Co., Ltd. The molding press used for molding is a double-steel-belt molding compound machine.

[0074] wherein the properties of each polyamide resin are as follows:

[0075] The viscosity of PA56 is 2.29, the terminal amino group content is 55 mmol / kg, and the melting point is 253℃;

[0076] The viscosity of PA510 is 2.51, the terminal amino group content is 54 mmol / kg, and the melting point is 217℃;

[0077] The viscosity of PA512 is 2.32, the terminal amino group content is 56 mmol / kg, and the melting point is 210℃;

[0078] The viscosity of PA6 is 2.3, the terminal amino group content is 54 mmol / kg, and the melting point is 223℃.

[0079] Preparation of PA510 unidirectional prepreg tape as shown in the preparation example 3 of the patent CN113232384A.

[0080] Preparation of PA512 unidirectional prepreg tape as shown in the preparation example 3 of the patent CN113232384A.

[0081] Preparation of bio-based polyamide 56 film

[0082] The PA56 resin is extruded by a double-screw extruder to obtain molten PA56, with a screw temperature of 265℃, and then extruded by a casting die to obtain a melt film, which is cooled and shaped by a casting roller and a cooling roller, with a cooling roller temperature of 30℃, and then adjusted by a film thickness gauge, with a die lip opening of 0.15mm to control the thickness deviation within ±2%, and then electrostatically eliminated and cut, to obtain a PA56 film with a thickness of 0.15mm.

[0083] Preparation of bio-based polyamide 510 film

[0084] The preparation method is the same as that of preparation example 3, except that the film raw material is PA510 resin, and finally a PA510 film with a thickness of 0.15mm is obtained.

[0085] Preparation of the polyamide 6 film of Comparative Preparation 1

[0086] The PA6 resin was extruded by a twin-screw extruder to obtain a melt PA6, the screw temperature was 230℃, and then the melt PA6 was extruded by a casting die to obtain a melt film, the melt film was cooled and shaped by a casting roller and a cooling roller, the cooling roller temperature was 30℃, and then the melt film was adjusted by a film thickness gauge, the die lip opening was adjusted to 0.15mm to control the thickness deviation within ±2%, electrostatic elimination and slitting were performed, and a PA6 film with a thickness of 0.15mm was obtained.

[0087] Preparation of the polyamide 6 unidirectional prepreg tape of Comparative Preparation 2

[0088] The preparation method was the same as that of Preparation Example 1, except that in step (1), the twin-screw extruder was in an eight-zone heating mode, and the temperatures of the first zone to the eighth zone (from feeding to the die head) were 200℃, 220℃, 245℃, 245℃, 245℃, 245℃, 245℃, and 245℃, respectively; the screw rotation speed was 400r / min; the length-diameter ratio of the twin-screw extruder was 1:36; the temperature of the melt filter was 250℃; and the die head temperature was 250℃, and finally a PA6 unidirectional prepreg tape was obtained.

[0089] Biobased polyamide composite board of Example 1

[0090] First surface layer A1: PA510 unidirectional prepreg tape (preparation method as in Preparation Example 1), thickness of 0.31mm, fiber content of 62.8wt%;

[0091] Middle layer B: PA56 film (preparation method as in Preparation Example 3), thickness of 0.15mm; plain glass fiber cloth, thickness of 0.175mm;

[0092] Second surface layer A2: PA510 unidirectional prepreg tape (preparation method as in Preparation Example 1), thickness of 0.31mm, fiber content of 62.8wt%;

[0093] The prepreg tapes and glass fiber cloth were cut into the size of the mold, a layer of release cloth or release paper was placed on the upper and lower layers of the mold, and different numbers of first surface layers, middle layers and second surface layers were placed in the middle, and continuous mold pressing was performed on a double steel belt mold pressing machine, specifically:

[0094] (1) One layer of PA510 unidirectional prepreg tape was laid on the first surface layer;

[0095] (2) the intermediate layer is laid 11 layers, the upper and lower layers are PA56 film layers, and the middle is alternately laid PA56 film and plain glass fiber cloth layers, and the PA56 film is laid 6 layers and the plain glass fiber cloth is laid 5 layers, that is, PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film;

[0096] (3) the second surface layer is laid 1 layer of PA510 unidirectional prepreg tape;

[0097] After the first surface layer, the intermediate layer and the second surface layer are sequentially laid, the mold pressing forming is performed, the temperature of the mold pressing machine is set to 265°C, and the pressure is controlled to 2 MPa, thereby preparing a bio-based polyamide composite board 1A1-[11B]-1A2 with a thickness of 2 mm and 13 layers. The structural schematic diagram is shown in Figure 1 .

[0098] Example 2 bio-based polyamide composite board

[0099] The first surface layer A1 is a PA512 unidirectional prepreg tape (the preparation method is as shown in Preparation Example 2), with a thickness of 0.31 mm and a fiber content of 62.8 wt%;

[0100] The intermediate layer B is a PA56 film (the preparation method is as shown in Preparation Example 3), with a thickness of 0.15 mm; and a plain glass fiber cloth, with a thickness of 0.175 mm;

[0101] The second surface layer A2 is a PA512 unidirectional prepreg tape (the preparation method is as shown in Preparation Example 2), with a thickness of 0.31 mm and a fiber content of 62.8 wt%;

[0102] The prepreg tape and the glass fiber cloth are cut into the size of the mold, a layer of release cloth or release paper is placed on the upper layer and the lower layer of the mold plate, and the first surface layer, the intermediate layer and the second surface layer with different layers are placed in the middle, and the continuous mold pressing forming is performed on the double-steel-belt mold pressing composite machine, specifically:

[0103] (1) the first surface layer is laid 1 layer of PA512 unidirectional prepreg tape;

[0104] (2) the intermediate layer is laid 11 layers, the upper and lower layers are PA56 film layers, and the middle is alternately laid PA56 film and plain glass fiber cloth layers, and the PA56 film is laid 6 layers and the plain glass fiber cloth is laid 5 layers, that is, PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film;

[0105] (3) the second surface layer is laid 1 layer of PA512 unidirectional prepreg tape;

[0106] 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 machine is set to 265°C, and the pressure is controlled to 2 MPa, to prepare a bio-based polyamide composite board 1A1-[11B]-1A2 with a thickness of 2 mm and 13 layers.

[0107] Example 3 Bio-based polyamide composite board

[0108] The raw materials of the first surface layer and the second surface layer are the same as in Example 1, and the difference lies in that the intermediate layer B is a PA510 film (preparation method as in Preparation Example 4) with a thickness of 0.15 mm; and the plain glass fiber cloth has a thickness of 0.175 mm.

[0109] The prepreg and the glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and continuous mold pressing forming is performed on the double-steel-belt mold pressing composite machine, specifically:

[0110] (1) The first surface layer is layered with 1 layer of PA510 unidirectional prepreg;

[0111] (2) The intermediate layer is layered with 11 layers, the upper and lower layers of which are layered with PA510 film, and the middle is layered with PA510 film and plain glass fiber cloth alternately, and a total of 6 layers of PA510 film and 5 layers of plain glass fiber cloth are layered, i.e., PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film;

[0112] (3) The second surface layer is layered with 1 layer of PA510 unidirectional prepreg;

[0113] 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 machine is set to 225°C, and the pressure is controlled to 2 MPa, to prepare a bio-based polyamide composite board 1A1-[11B]-1A2 with a thickness of 2 mm and 13 layers.

[0114] Example 4 Bio-based polyamide composite board

[0115] The raw materials of the first surface layer and the second surface layer are the same as in Example 2, and the difference lies in that the intermediate layer B is a PA510 film (preparation method as in Preparation Example 4) with a thickness of 0.15 mm; and the plain glass fiber cloth has a thickness of 0.175 mm.

[0116] The prepreg and the glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and continuous mold pressing forming is performed on the double-steel-belt mold pressing composite machine, specifically:

[0117] (1) The first surface layer is paved with 1 layer of PA512 unidirectional prepreg tape;

[0118] (2) The middle layer is paved with 11 layers, the upper and lower surface layers are paved with PA510 film layers, and the middle is paved with PA510 film and plain glass fiber cloth layers alternately, and there are 6 layers of PA510 film and 5 layers of plain glass fiber cloth, i.e. PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film;

[0119] (3) The second surface layer is paved with 1 layer of PA512 unidirectional prepreg tape;

[0120] After the first surface layer, the middle layer, and the second surface layer are sequentially paved, molding is performed, the temperature of the molding machine is set to 225°C, and the pressure is controlled to 2 MPa, thereby preparing a bio-based polyamide composite board 1A1-[11B]-1A2 with a thickness of 2 mm and 13 layers.

[0121] Example 5 Bio-based polyamide composite board

[0122] The first surface layer, the second surface layer, and the middle layer are made of the same raw materials as in Example 1, and the difference lies in the paving method: the prepreg tape and the glass fiber cloth are cut into the size of the mold, 1 layer of release cloth or release paper 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 continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0123] (1) The first surface layer is paved with 1 layer of PA510 unidirectional prepreg tape;

[0124] (2) The middle layer is paved with 23 layers, the upper and lower surface layers are paved with PA56 film layers, and the middle is paved with PA56 film and plain glass fiber cloth layers alternately, and there are 12 layers of PA56 film and 11 layers of plain glass fiber cloth, i.e. PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film;

[0125] (3) The second surface layer is paved with 1 layer of PA510 unidirectional prepreg tape;

[0126] After the first surface layer, the middle layer, and the second surface layer are sequentially paved, molding is performed, the temperature of the molding machine is set to 265°C, and the pressure is controlled to 2 MPa, thereby preparing a bio-based polyamide composite board 1A1-[23B]-1A2 with a thickness of 4 mm and 25 layers.

[0127] Example 6 Bio-based polyamide composite sheet

[0128] The first surface layer, the second surface layer, and the intermediate layer are the same as those in Example 2, except that the layering method is different: the prepreg and glass cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and continuous molding is performed on a double steel belt molding composite machine, specifically:

[0129] (1) The first surface layer is layered with 1 layer of PA512 unidirectional prepreg;

[0130] (2) The intermediate layer is layered with 23 layers, the upper and lower layers of which are PA56 film layers, and the middle is an alternating layer of PA56 film and plain glass cloth, with a total of 12 layers of PA56 film and 11 layers of plain glass cloth, i.e., PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film-glass cloth-PA56 film;

[0131] (3) The second surface layer is layered with 1 layer of PA512 unidirectional prepreg;

[0132] After the first surface layer, the intermediate layer, and the second surface layer are layered in order, molding is performed, the temperature of the molding machine is set to 265°C, and the pressure is controlled at 2 MPa, to produce a bio-based polyamide composite sheet 1A1-[23B]-1A2 with a thickness of 4 mm and 25 layers.

[0133] Example 7 Bio-based polyamide composite sheet

[0134] The first surface layer, the second surface layer, and the intermediate layer are the same as those in Example 3, except that the layering method is different: the prepreg and glass cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and continuous molding is performed on a double steel belt molding composite machine, specifically:

[0135] (1) The first surface layer is layered with 1 layer of PA510 unidirectional prepreg;

[0136] (2) the middle layer is laid in 23 layers, the upper and lower layers of which are PA510 film layers, and the middle is alternately laid with PA510 film and plain glass fiber cloth, with 12 layers of PA510 film and 11 layers of plain glass fiber cloth, i.e. PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film;

[0137] (3) the second surface layer is laid in 1 layer of PA510 unidirectional prepreg tape;

[0138] After the first surface layer, the middle layer, and the second surface layer are sequentially laid, molding is performed, the temperature of the molding machine is set to 225°C, and the pressure is controlled to 2 MPa, to prepare a bio-based polyamide composite board 1A1-[23B]-1A2 with a thickness of 4 mm and 25 layers.

[0139] Bio-based polyamide composite board of Example 8

[0140] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 4, and the difference lies in the different laying methods: the prepreg tape and the glass fiber cloth are cut into the size of the mold, 1 layer of release cloth or release paper 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 continuous molding is performed on a double-steel-belt molding composite machine, specifically:

[0141] (1) the first surface layer is laid in 1 layer of PA512 unidirectional prepreg tape;

[0142] (2) the middle layer is laid in 23 layers, the upper and lower layers of which are PA510 film layers, and the middle is alternately laid with PA510 film and plain glass fiber cloth, with 12 layers of PA510 film and 11 layers of plain glass fiber cloth, i.e. PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film;

[0143] (3) the second surface layer is laid in 1 layer of PA512 unidirectional prepreg tape;

[0144] The first surface layer, the middle layer, and the second surface layer are sequentially layered and then subjected to mold pressing forming, the temperature of the mold pressing machine is set to 225°C, and the pressure is controlled to 2MPa, to prepare a bio-based polyamide composite board 1A1-[23B]-1A2 with a thickness of 4mm and 25 layers.

[0145] Example 9 Bio-based polyamide composite board

[0146] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 1, except that the layering method is different: the prepreg and glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper 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 continuous mold pressing forming is performed on a double steel belt mold pressing composite machine, specifically:

[0147] (1) The first surface layer is layered with 2 layers of PA510 unidirectional prepreg, which is layered according to the 90° cross direction of the long glass fiber;

[0148] (2) The middle layer is layered with 7 layers, the upper and lower layers of which are PA56 film, and the middle is PA56 film and plain glass fiber cloth layered alternately, with 4 layers of PA56 film and 3 layers of plain glass fiber cloth, i.e. PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film-glass fiber cloth-PA56 film

[0149] (3) The second surface layer is layered with 2 layers of PA510 unidirectional prepreg, which is layered according to the 90° cross direction of the long glass fiber;

[0150] The first surface layer, the middle layer, and the second surface layer are sequentially layered and then subjected to mold pressing forming, the temperature of the mold pressing machine is set to 265°C, and the pressure is controlled to 2MPa, to prepare a bio-based polyamide composite board 2A1-[7B]-2A2 with a thickness of 2mm and 11 layers.

[0151] Example 10 Bio-based polyamide composite board

[0152] The first surface layer, the second surface layer, and the middle layer have the same raw materials as in Example 3, except that the layering method is different: the prepreg and glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper 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 continuous mold pressing forming is performed on a double steel belt mold pressing composite machine, specifically:

[0153] (1) The first surface layer is layered with 2 layers of PA510 unidirectional prepreg, which is layered according to the 90° cross direction of the long glass fiber;

[0154] (2) the middle layer is 7 layers of PA510 film, and the upper and lower layers are alternately layered with PA510 film and plain glass fiber cloth, and 4 layers of PA510 film and 3 layers of plain glass fiber cloth are layered, that is, PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film-glass fiber cloth-PA510 film

[0155] (3) the second surface layer is 2 layers of PA510 unidirectional prepreg, and the long glass fiber direction is crossed at 90°;

[0156] After the first surface layer, the middle layer and the second surface layer are sequentially layered, the mold pressing machine is set to 225°C, and the pressure is controlled to 2 MPa, to prepare a bio-based polyamide composite board 2A1-[7B]-2A2 with a thickness of 2 mm and 11 layers.

[0157] Comparative Example 1: Polyamide 6 composite board

[0158] The first surface layer A1 is a PA510 unidirectional prepreg (preparation method as in Preparation Example 1), with a thickness of 0.31 mm and a fiber content of 62.8 wt%;

[0159] The middle layer B is a PA6 film (preparation method as in Comparative Preparation Example 1), with a thickness of 0.15 mm; and a plain glass fiber cloth with a thickness of 0.175 mm;

[0160] The second surface layer A2 is a PA510 unidirectional prepreg (preparation method as in Preparation Example 1), with a thickness of 0.31 mm and a fiber content of 62.8 wt%;

[0161] The prepreg and the glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper is placed on the upper and lower layers of the mold, and different numbers of the first surface layer, the middle layer and the second surface layer are placed in the middle, and continuous mold pressing is performed on a double steel belt mold pressing composite machine, specifically:

[0162] (1) the first surface layer is 1 layer of PA510 unidirectional prepreg;

[0163] (2) the middle layer is 11 layers of PA6 film, and the upper and lower layers are alternately layered with PA6 film and plain glass fiber cloth, and 6 layers of PA6 film and 5 layers of plain glass fiber cloth are layered, that is, PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film;

[0164] (3) the second surface layer is 1 layer of PA510 unidirectional prepreg;

[0165] 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 machine is set to 235°C, and the pressure is controlled to 2MPa, thereby preparing a PA6 composite board 1A1-[11B]-1A2 with a thickness of 2mm and 13 layers.

[0166] Polyamide 6 composite board of Comparative Example 2

[0167] The first surface layer, the second surface layer and the intermediate layer have the same raw materials as Comparative Example 1, except that the layering method is different: the prepreg and the glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and then subjected to continuous mold pressing forming on a double steel belt mold pressing composite machine, specifically:

[0168] (1) The first surface layer is layered with 1 layer of PA510 unidirectional prepreg;

[0169] (2) The intermediate layer is layered with 23 layers, the upper and lower layers of which are layered with PA6 film, and the middle is layered with PA6 film and plain glass fiber cloth alternately, and a total of 12 layers of PA6 film and 11 layers of plain glass fiber cloth are layered, i.e. PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film;

[0170] (3) The second surface layer is layered with 1 layer of PA510 unidirectional prepreg;

[0171] 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 machine is set to 235°C, and the pressure is controlled to 2MPa, thereby preparing a PA6 composite board 1A1-[11B]-1A2 with a thickness of 2mm and 13 layers.

[0172] Polyamide 6 composite board of Comparative Example 3

[0173] The first surface layer, the second surface layer and the intermediate layer have the same raw materials as Comparative Example 1, except that the layering method is different: the prepreg and the glass fiber cloth are cut to the size of the mold, 1 layer of release cloth or release paper is 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 are placed in the middle, and then subjected to continuous mold pressing forming on a double steel belt mold pressing composite machine, specifically:

[0174] (1) The first surface layer is layered with 2 layers of PA510 unidirectional prepreg, which are layered according to the direction of the long glass fiber at an angle of 90°;

[0175] (2) the middle layer is 7 layers of PA6 film, and the upper and lower layers are 4 layers of PA6 film and 3 layers of plain glass fiber cloth, i.e. PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film

[0176] (3) the second surface layer is 2 layers of PA510 unidirectional prepreg, and the long glass fiber direction is 90° cross-laid;

[0177] After the first surface layer, the middle layer and the second surface layer are sequentially laid, the mold pressing forming is performed, the temperature of the mold pressing machine is set to 235°C, and the pressure is controlled to 2 MPa, thereby preparing a PA6 composite board 2A1-[7B]-2A2 with a thickness of 2 mm and 11 layers.

[0178] Comparative Example 4: polyamide 6 composite board

[0179] The first surface layer A1 is a PA6 unidirectional prepreg (the preparation method is as shown in Comparative Preparation Example 2), with a thickness of 0.32 mm and a fiber content of 61.4 wt%;

[0180] The middle layer B is a PA6 film (the preparation method is as shown in Comparative Preparation Example 1), with a thickness of 0.15 mm; and a plain glass fiber cloth, with a thickness of 0.175 mm

[0181] The second surface layer A2 is a PA6 unidirectional prepreg (the preparation method is as shown in Comparative Preparation Example 2), with a thickness of 0.32 mm and a fiber content of 61.4 wt%;

[0182] The prepreg and the glass fiber cloth are cut into the size of the mold, 1 layer of release cloth or release paper is placed on the upper layer and the lower layer of the mold plate, and the first surface layer, the middle layer and the second surface layer with different layers are placed in the middle, and the continuous mold pressing forming is performed on the double-steel-belt mold pressing composite machine, specifically:

[0183] (1) the first surface layer is 2 layers of PA6 unidirectional prepreg, and the long glass fiber direction is 90° cross-laid;

[0184] (2) the middle layer is 7 layers of PA6 film, and the upper and lower layers are 4 layers of PA6 film and 3 layers of plain glass fiber cloth, i.e. PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film-glass fiber cloth-PA6 film

[0185] (3) the second surface layer is 2 layers of PA6 unidirectional prepreg, and the long glass fiber direction is 90° cross-laid;

[0186] The first surface layer, the middle layer and the second surface layer are sequentially laid and then molded to prepare a PA6 composite board 2A1-[7B]-2A2 with a thickness of 2 mm and 11 layers.

[0187] The composite board prepared in the above examples and comparative examples is tested according to the following standards, and the test results are shown in Table 1.

[0188] 1. Bending strength and bending modulus: according to the standard requirement of ASTM D790-2017, a sample size of 127 mm long, 12.7 mm wide and 2 mm thick is cut for bending experiment.

[0189] 2. Heat distortion temperature (HDT) test: according to the national standard GB / T 1634.2-2004, a sample size of 120 mm long, 10 mm wide and 4 mm thick is prepared, and a bending stress of 1.8 MPa is applied.

[0190] 3. Water absorption test: according to the standard ASTM-D570-2005, a sample size of 60 mm long, 60 mm wide and 2 mm thick is prepared, and according to the plastic method, the test time is 24 h.

[0191] 4. Fiber content test of the composite board: according to the national standard GB / T 9345.1-2008, calcination is carried out at a high temperature of 700℃ for 2 hours.

[0192] Table 1

[0193]

[0194] As can be seen from Table 1, by comparing the examples with the comparative examples, it can be found that the mechanical properties of the continuous long glass fiber reinforced bio-based polyamide composite board are obviously improved compared with the corresponding properties of the continuous long glass fiber reinforced PA6 composite board, the heat resistance is also significantly better than that of the continuous long glass fiber reinforced PA6 composite board, and the water absorption is lower than that of the continuous long glass fiber reinforced PA6 composite board.

[0195] Unless specifically limited, the terms used in the present application have the meanings generally understood by those skilled in the art.

[0196] The embodiments described in the present application are for illustrative purposes only and are not intended to limit the scope of protection of the present application, and those skilled in the art can make various other replacements, changes and improvements within the scope of the present application, therefore, the present application is not limited to the above embodiments, but is limited only by the claims.

Claims

1. A bio-based polyamide composite board, characterized in that, It includes 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 sequentially; the first surface layer and the second surface layer are unidirectional prepreg tapes of long carbon chain polyamide resin, and the intermediate layer includes a bio-based polyamide film and a fiber cloth; The long-chain polyamide resin unidirectional prepreg tape is a continuous long fiber reinforced long-chain polyamide resin unidirectional prepreg tape, which includes continuous long fibers and bio-based long-chain polyamide 5X resin. The bio-based long-chain polyamide 5X resin is selected from one or more of PA510, PA511, PA512, PA513, PA514, PA515, PA516, PA517 and PA518.

2. The bio-based polyamide composite board according to claim 1, characterized in that, The continuous long fibers comprise 40-80% by mass.

3. The bio-based polyamide composite board according to claim 1, characterized in that, The continuous long fibers comprise 60-70% by mass.

4. The bio-based polyamide composite board according to claim 1, characterized in that, The bio-based long-chain polyamide 5X resin has a relative viscosity of 1.8-2.7; terminal amino content of 42-60 mmol / kg; melting point of 170℃-320℃; and bio-based content of 28%-100%.

5. The bio-based polyamide composite board according to claim 1, characterized in that, The relative viscosity of the bio-based long-chain polyamide 5X resin is 2.1-2.

6.

6. The bio-based polyamide composite board according to claim 1, characterized in that, The melting point of the bio-based long carbon chain polyacrylamide is 180-230℃.

7. The bio-based polyamide composite board according to claim 1, characterized in that, The continuous long fibers include carbon fiber, glass fiber, basalt fiber or aramid fiber.

8. The bio-based polyamide composite board according to claim 1, characterized in that, The continuous long fiber is a continuous long glass fiber or a continuous long carbon fiber.

9. The bio-based polyamide composite board according to claim 1, characterized in that, The thickness of the long-chain polyamide resin unidirectional prepreg tape is 0.15-0.5 mm.

10. The bio-based polyamide composite board according to claim 9, characterized in that, The thickness of the long-chain polyamide resin unidirectional prepreg tape is 0.21-0.33 mm.

11. The bio-based polyamide composite board according to claim 1, characterized in that, The thickness of the bio-based polyamide film is 0.01-5 mm.

12. The bio-based polyamide composite board according to claim 1, characterized in that, The bio-based polyamide film is obtained by casting bio-based polyamide resin / melt.

13. The bio-based polyamide composite board according to claim 1, characterized in that, The bio-based polyamide in the bio-based polyamide film is selected from one or more of PA56, PA510, PA511, PA512, PA513, PA514, PA515 and PA516.

14. The bio-based polyamide composite board according to claim 12, characterized in that, The bio-based polyamide film is obtained by extruding bio-based polyamide resin through a screw at 220℃-300℃ to obtain molten polyamide, extruding it through a casting die to obtain a molten film, and then cooling and shaping it through casting rollers and cooling rollers, winding it up, and slitting it.

15. The bio-based polyamide composite board according to claim 14, characterized in that, The temperature of the cooling roller is 20-40℃.

16. The bio-based polyamide composite board according to claim 1, characterized in that, The fiber cloth includes any one or more of the following: woven fabric, unidirectional fabric, unidirectional prepreg, bidirectional prepreg, or multiaxial fabric made of carbon fiber, glass fiber, basalt fiber, or aramid fiber.

17. The bio-based polyamide composite board according to claim 16, characterized in that, The thickness of the fiber cloth is 0.1-0.4 mm.

18. The bio-based polyamide composite board according to claim 16, characterized in that, The thickness of the fiber cloth is 0.175-0.193 mm.

19. The bio-based polyamide composite board according to claim 1, characterized in that, The layup method between the first top layer, the intermediate layer, and the second top layer is either parallel layup or cross layup.

20. The bio-based polyamide composite board according to claim 19, characterized in that, The intermediate layer consists of alternating layers of bio-based polyamide film and fiber cloth.

21. The bio-based polyamide composite board according to claim 19, characterized in that, The first and second surface layers each have one or more layers.

22. The bio-based polyamide composite board according to claim 19, characterized in that, The number of intermediate layers is two or more.

23. The bio-based polyamide composite board according to claim 19, characterized in that, The total number of layers, including the first surface layer, the intermediate layer, and the second surface layer, is 5-200.

24. The bio-based polyamide composite board according to claim 1, characterized in that, The thickness of the bio-based polyamide composite board is 0.5 mm or more.

25. The bio-based polyamide composite board according to claim 24, characterized in that, The thickness of the bio-based polyamide composite board is 1-40mm.

26. A method for preparing a bio-based polyamide composite board as described in any one of claims 1-25, characterized in that, The first surface layer, the intermediate layer, and the second surface layer are sequentially laid out and then molded. The molding temperature is 170-310℃ and the molding pressure is 0-5 MPa.

27. The method for preparing the bio-based polyamide composite board as described in claim 26, characterized in that, The molding temperature is 5-10°C higher than the melting point of the bio-based polyamide resin.

28. The method for preparing the bio-based polyamide composite board as described in claim 27, characterized in that, The molding temperature is 225-265℃.

29. The method for preparing the bio-based polyamide composite board as described in claim 26, characterized in that, The molding method is either continuous molding or direct molding.

30. The method for preparing the bio-based polyamide composite board as described in claim 29, characterized in that, When the compression molding method is continuous compression molding, the steps include preheating for 5-7 minutes and holding pressure for 8-10 minutes.

31. The method for preparing the bio-based polyamide composite board as described in claim 29, characterized in that, When the compression molding method is direct compression molding, the steps include preheating, venting, pressure holding, and cooling.

32. The method for preparing the bio-based polyamide composite board as described in claim 26, characterized in that, Before each layer is laid up, the material of each layer is dried.

33. The method for preparing the bio-based polyamide composite board as described in claim 32, characterized in that, The drying temperature is 85-120℃.

34. The method for preparing the bio-based polyamide composite board as described in claim 32, characterized in that, The drying time is 4-25 hours.

35. The method for preparing the bio-based polyamide composite board as described in claim 34, characterized in that, The drying time is 15-24 hours.

36. A molded article comprising the bio-based polyamide composite sheet as described in any one of claims 1-25.

37. The application of a bio-based polyamide composite panel as described in any one of claims 1-25 in the aerospace, military, automotive, sporting goods, building materials, or electronic and electrical applications.

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