Bio-based polyamide sandwich panel

Abstract

The utility model discloses a bio-based polyamide sandwich panel which comprises an upper skin layer, a lower skin layer and a core layer positioned between the upper skin layer and the lower skin layer, the upper skin layer and the lower skin layer are respectively and independently formed by compounding at least two layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tapes and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tapes, the core layer adopts a bio-based polyamide foam board, and the upper skin layer, the lower skin layer and the core layer are integrally formed through hot pressing. The bio-based polyamide sandwich panel provided by the utility model has the characteristics of high strength, high modulus, light weight and the like, and is suitable for being used as a wall panel of a wind power blade, a building template, a tray, a refrigerator car carriage or a refrigerated container.

Description

Technical Field

[0001] The utility model relates to a bio-based polyamide sandwich plate. Background Art

[0002] In recent years, with the rapid development of science and technology, the demand for composite sandwich panels in the fields of construction, transportation, and prefabricated houses has increased, and various types of composite sandwich panels have emerged. Not only are the structures and styles of the panels unique, but the functions are also undergoing earth-shaking changes. People not only require them to have a smooth and beautiful appearance and reliable quality, but also require them to have high strength, high modulus, light weight, thermal insulation, and other properties.

[0003] The commonly used composite sandwich panels on the market are metal panels and non-metal panels, such as wood panels, fiberglass panels, etc. However, metal panels have high density, poor corrosion resistance, and poor thermal insulation effect; wood panels are flammable and easily damaged by water absorption; fiberglass panels have high density, high pollution, and cannot be recycled.

[0004] Recently, continuous fiber reinforced thermoplastic composite sandwich panels have become an application trend in the market. The existing sandwich panels are sandwich structures in which a thermoplastic lightweight composite material core is arranged between multiple layers of unidirectional continuous glass fiber thermoplastic resin prepreg sheets and / or fiber fabric reinforced thermoplastic resin prepreg composite surface layers, so that the sandwich panels have sufficient longitudinal and transverse performances and are lightweight and recyclable. However, the core material is a thermoplastic lightweight composite sheet reinforced with glass fiber mat. When it is thin, the bending stiffness of the board is insufficient, and when it is thick, the weight is relatively large, and it is difficult to achieve a balance between bending stiffness and weight. Utility Model Content

[0005] In order to solve the above-mentioned problems existing in the prior art, the utility model provides a bio-based polyamide sandwich panel, which uses continuous fiber reinforced bio-based polyamide unidirectional prepreg tape and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape as the skin layer, and uses a bio-based polyamide foam board as the core layer. The sandwich panel formed by molding has good mechanical properties and is light in overall weight, which better meets the demand for lightweight panels and is suitable for use as wind turbine blades, building formwork, pallets, refrigerated truck body panels or refrigerated container wall panels.

[0006] The unidirectional prepreg tape laying method and structure described in the utility model is a limitation on the sandwich plate structure, not on the material components.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A bio-based polyamide sandwich panel, comprising an upper skin layer, a lower skin layer and a core layer located between the upper skin layer and the lower skin layer, wherein the upper skin layer and the lower skin layer are each independently composited by at least two layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tapes and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tapes, the core layer adopts a bio-based polyamide foam board, and the upper skin layer, the lower skin layer and the core layer are integrally formed by hot pressing.

[0009] According to an embodiment of the present invention, the directions of the continuous fibers in two adjacent layers of the unidirectional prepreg tapes are crossed at 0-90°.

[0010] According to an embodiment of the present invention, the directions of the continuous fiber fabrics in two adjacent layers of the unidirectional prepreg tapes are crossed at 0-90 degrees.

[0011] According to an embodiment of the present invention, the directions of the continuous fibers and the continuous fiber fabrics in two adjacent layers of the unidirectional prepreg tapes are crossed at 0-90 degrees.

[0012] According to an embodiment of the utility model, the upper skin layer and the lower skin layer are each independently formed by at least two layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tapes and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tapes according to [0 / 90] ns , [90 / 0] ns [0 / 90 / 0] ns , [90 / 0 / 90] ns [0 / 90 / 90 / 0] ns ,[90 / 0 / 0 / 90] ns , [0 / 90 / 90 / 0 / 90 / 0] ns , [90 / 0 / 90 / 0 / 0 / 90] ns , [0 / 90 / 90 / 0 / 0 / 90 / 90 / 0] ns , [0 / 90 / 0 / 90 / 90 / 0 / 90 / 0] ns or [90 / 0 / 90 / 0 / 0 / 90 / 0 / 90] ns The laminate is formed by hot pressing and compounding in any of the above-mentioned lamination methods, wherein n is the number of unit cycles and n is an integer greater than 1. Wherein s is the first letter of the English word "symmetry", indicating that the above-mentioned lamination method should meet the principle of symmetrical lamination.

[0013] According to an embodiment of the present utility model, the number of layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tape and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape laid in the upper skin layer and the lower skin layer is 2-6.

[0014] According to the implementation scheme of the utility model, the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape is a tape-shaped structural material with a bio-based polyamide resin as a matrix and continuous fibers as a reinforcement.

[0015] According to an embodiment of the present invention, the continuous fiber volume ratio of the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape is 30-75% vol. The volume ratio refers to the volume of the continuous fiber occupied by the volume of the prepreg tape.

[0016] According to an embodiment of the present invention, the type of the continuous fiber includes one or a combination of carbon fiber, glass fiber, silicon carbide fiber, basalt fiber, natural flax fiber, aramid fiber, semi-aromatic polyamide fiber or polyolefin fiber.

[0017] According to the implementation scheme of the present utility model, the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape includes continuous carbon fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous glass fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous silicon carbide fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous basalt fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous natural flax fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous aramid fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous semi-aromatic polyamide fiber reinforced bio-based polyamide unidirectional prepreg tape or continuous polyolefin fiber reinforced bio-based polyamide unidirectional prepreg tape.

[0018] According to a preferred embodiment of the utility model, the continuous fiber is a continuous glass fiber, and the monofilament diameter can be 8-17 μm, and further 8-13 μm. Preferably, the linear density of the continuous glass fiber is 1200-4800 Tex, such as 1200 Tex, 2400 Tex, and 3600 Tex. The continuous 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 Jushi.

[0019] According to a preferred embodiment of the utility model, the continuous fiber is a continuous carbon fiber, for example, a polyacrylonitrile carbon fiber; the number of monofilaments of the continuous carbon fiber can be 10K-60K, for example, 12K, 24K, 36K. The monofilament diameter of the continuous carbon fiber can be 5-10 μm. The continuous carbon fiber is, for example, Toray T700 with a specification of 24K, Guangwei Composites continuous carbon fiber 700S with a specification of 12K or 24K.

[0020] According to the implementation scheme of the utility model, the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape can be prepared by solution impregnation technology, melt coating technology, suspension impregnation technology, co-woven fibers, powder impregnation technology and melt impregnation method.

[0021] According to an embodiment of the present utility model, the thickness of the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape is 0.15-5 mm, preferably 0.2-0.35 mm, such as 0.25 mm, 0.31 mm, 0.32 mm, 0.33 mm.

[0022] According to the implementation scheme of the utility model, the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape is a belt-shaped structural material with bio-based polyamide resin as a matrix and continuous fiber plain, twill, satin or biaxial fabric as a reinforcement.

[0023] According to an embodiment of the utility model, the volume ratio of the continuous fiber fabric of the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape is 35-75% vol. The volume ratio refers to the volume of the continuous fiber fabric occupied by the volume of the prepreg tape.

[0024] According to an embodiment of the utility model, the type of the continuous fiber fabric includes one or a combination of carbon fiber fabric, glass fiber fabric, silicon carbide fiber fabric, basalt fiber fabric, natural flax fiber fabric, aramid fiber fabric, semi-aromatic polyamide fiber fabric or polyolefin fiber fabric.

[0025] According to the implementation scheme of the present utility model, the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape includes continuous carbon fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous glass fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous silicon carbide fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous basalt fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous natural flax fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous aramid fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous semi-aromatic polyamide fiber fabric reinforced bio-based polyamide unidirectional prepreg tape or continuous polyolefin fiber fabric reinforced bio-based polyamide unidirectional prepreg tape.

[0026] According to the implementation scheme of the utility model, the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape can be prepared by solution impregnation technology, powder impregnation technology and melt impregnation method. For example, referring to patents US4098943 and US4469543, the continuous fiber fabric can be compounded with extruded thermoplastic resin film or thermoplastic powder, and then heated and melt-impregnated to obtain it.

[0027] According to an embodiment of the present utility model, the thickness of the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape is 0.15-5 mm, preferably 0.2-0.35 mm, such as 0.25 mm, 0.31 mm, 0.32 mm, 0.33 mm.

[0028] According to an embodiment of the present invention, the bio-based polyamide in the continuous fiber reinforced bio-based polyamide unidirectional prepreg or the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg is selected from bio-based polyamide PA56, bio-based polyamide PA510, bio-based polyamide PA511, bio-based polyamide PA512, bio-based polyamide PA513, bio-based polyamide PA514, bio-based polyamide PA515 and bio-based polyamide PA516, bio-based polyamide PA56 / 5T, bio-based polyamide PA510 / 5T, bio-based polyamide PA511 / 5T, bio-based polyamide PA512 / 5T, bio-based polyamide PA513 / 5T, bio-based polyamide PA514 / 5T, bio-based polyamide PA515 / 5T, bio-based polyamide PA516 / 5T, bio-based polyamide PA56 / 5I, commercially available 6638, 6308, 6300, 6290, 6635, 6631, 6632, 6520, 5000, 3600, 3601, 3100, 3102, 3300, 3500, 2260, 2262, 1273, 1251, Any one or a combination of 1320.

[0029] It should be noted that It is the brand of semi-biobased or fully bio-based polyamide raw materials of Shanghai Cathay Biotechnology Co., Ltd. The numbers behind are the grades of polyamide corresponding to different performance indicators. Its main raw materials come from renewable plant raw materials, with a bio-based content of 25%-100%. It has the characteristics of renewable sources, recyclable products, standard performance and competitive costs.

[0030] According to the embodiments of the present invention, the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape or the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape are materials known in the art.

[0031] According to the embodiment of the utility model, the density of the bio-based polyamide foam board is 80-200 kg / m3 , preferably 100-200kg / m 3 , for example 100kg / m 3 , 150kg / m 3 , 200kg / m 3 .

[0032] According to the implementation scheme of the utility model, the material of the bio-based polyamide foam board is selected from bio-based polyamide PA56, bio-based polyamide PA510, bio-based polyamide PA511, bio-based polyamide PA512, bio-based polyamide PA513, bio-based polyamide PA514, bio-based polyamide PA515 and bio-based polyamide PA516, bio-based polyamide PA56 / 5T, bio-based polyamide PA510 / 5T, bio-based polyamide PA511 / 5T, bio-based polyamide PA512 / 5T, bio-based polyamide PA513 / 5T, bio-based polyamide PA514 / 5T, bio-based polyamide PA515 / 5T, bio-based polyamide PA516 / 5T, bio-based polyamide PA56 / 5I, commercially available 6638, 6308, 6300, 6290, 6635, 6631, 6632, 6520, 5000, 3600, 3601, 3100, 3102, 3300, 3500, 2260, 2262, 1273, 1251, Any one or a combination of 1320.

[0033] According to the implementation scheme of the utility model, the bio-based polyamide foam board includes bio-based polyamide PA56 foam board, bio-based polyamide PA510 foam board, bio-based polyamide PA511 foam board, bio-based polyamide PA512 foam board, bio-based polyamide PA513 foam board, bio-based polyamide PA514 foam board, bio-based polyamide PA515 foam board, bio-based polyamide PA516 foam board, bio-based polyamide PA56 / 5T foam board, bio-based polyamide PA510 / 5T foam board, bio-based polyamide PA511 / 5T foam board, bio-based polyamide PA512 / 5T foam board, bio-based polyamide PA513 / 5T foam board, bio-based polyamide PA514 / 5T foam board, bio-based polyamide PA515 / 5T foam board, bio-based polyamide PA516 / 5T foam board, bio-based polyamide PA56 / 5I foam board, 6638 foam board, 6308 foam board, 6300 foam board, 6290 foam board, 6635 foam board, 6631 foam board, 6632 foam board, 6520 foam board, 5000 foam board, 3600 foam board, 3601 foam board, 3100 foam board, 3102 foam board, 3300 foam board, 3500 foam board, 2260 foam board, 2262 foam board, 1273 foam board, 1251 foam board or 1320 Foam board.

[0034] According to the embodiment of the utility model, the bio-based polyamide foam board can be prepared by a conventional foaming molding process and is a known material in the art.

[0035] According to the implementation scheme of the utility model, the thickness of the core layer is 5-50 mm. The thickness of the core layer should not be too thick or too thin. A too thick core layer has a high cost and a large weight, while a too thin core layer is difficult to meet the strength requirements. The use of the bio-based polyamide foam board of the above thickness can conveniently provide a solution that meets the above requirements at the same time.

[0036] According to the embodiment of the utility model, the thickness of the upper skin layer and the lower skin layer is independently 0.15-10mm, for example, 1mm, 2mm. The thickness of the upper skin layer and the lower skin layer should not be too thick or too thin. Too thick surface layer and bottom layer are heavy and have poor toughness, while too thin surface layer is not convenient for forming strong protection for the core layer and has insufficient bending strength. Using more than 2 layers, preferably 2-4 layers, of continuous fiber reinforced bio-based polyamide unidirectional prepreg tape with a thickness of 0.15-0.5mm, preferably 0.21-0.33mm, can effectively take into account the strength and toughness of the sandwich panel.

[0037] According to the implementation scheme of the utility model, the total number of layers of the upper skin layer, the core layer and the lower skin layer is 5-20 layers, for example, 5 layers, 7 layers, 9 layers, 11 layers, 13 layers, 15 layers, etc., and more preferably 5-8 layers; for example, when the total number of layers is 5 layers, the bio-based polyamide sandwich panel material is, starting from the upper skin layer, in sequence: continuous fiber reinforced bio-based polyamide unidirectional prepreg tape-continuous fiber reinforced bio-based polyamide unidirectional prepreg tape-bio-based polyamide foam board-continuous fiber reinforced bio-based polyamide unidirectional prepreg tape-continuous fiber reinforced bio-based polyamide unidirectional prepreg tape.

[0038] According to the implementation scheme of the utility model, different total numbers of layers can be set according to the thickness of the sandwich panel material for molding.

[0039] According to the implementation scheme of the utility model, the thickness of the bio-based polyamide sandwich panel is 5-70 mm, for example, 19 mm, 20 mm. The thickness of the bio-based polyamide sandwich panel should not be too thick or too thin. An overly thick sandwich panel will result in excessive weight, which is not conducive to transportation and will occupy storage space, while an overly thin composite panel will have difficulty in meeting the structural strength and toughness requirements. Using a sandwich panel within the above thickness range can further effectively balance the strength and toughness of the sandwich panel.

[0040] According to the implementation scheme of the utility model, according to different application scenarios, a mixed prepreg tape laying method can be adopted in combination with different types of foam boards, that is, different types of unidirectional prepreg tapes and different laying methods are used for the upper skin layer and the lower skin layer, such as different types or contents of continuous long fibers, different types or contents of continuous long fiber fabrics, different types of bio-based polyamide resins, etc.; different types of polyamide foam boards are used as the core material, such as different densities, different types of bio-based polyamide resins, etc.

[0041] According to the implementation scheme of the utility model, the bio-based polyamide sandwich panel can be prepared by the following method: the upper skin layer, the core layer and the lower skin layer are sequentially layered and then compression molded, and the temperature is controlled to be 270-340°C and the pressure is 0-5MPa.

[0042] Preferably, the compression molding is performed by continuous compression molding or direct compression molding, more preferably continuous compression molding.

[0043] Preferably, the temperature of the compression molding is controlled to be 275-310°C.

[0044] Preferably, the pressure of the compression molding is controlled to be 1-5 MPa, such as 2 MPa.

[0045] In some specific embodiments, the compression molding method may be a conventional compression molding method in the art, such as continuous compression molding or direct compression molding, preferably continuous compression molding.

[0046] In some specific embodiments, when the compression molding method is continuous compression molding, the conventional continuous automatic layering steps in the art can be followed.

[0047] When the compression molding method is direct compression molding, the direct compression molding may include the steps of preheating, exhausting, pressure holding, and cooling according to the conventional techniques in the art.

[0048] In the utility model, before the layering, it is preferred to further include a step of drying the material of each layer. Reducing the water content of the material by drying can prevent excessive bubbles from being generated during the molding process.

[0049] The drying operation may be a conventional drying operation in the art, such as vacuum drying. The drying temperature is preferably 85-120° C., such as 105° C. The drying time is preferably 4-25 h, and further 15-24 h, such as 15 h, 20 h, 24 h.

[0050] The positive and progressive effects of the utility model are:

[0051] 1. The prepreg tape and foam board in the bio-based polyamide sandwich panel of the utility model both contain bio-based polyamide resin, which has a high bio-based content and conforms to the concept of sustainable development of material sources. The high bio-based content effectively reduces the use of fossil raw materials, thereby reducing carbon emissions.

[0052] 2. The bio-based polyamide sandwich panel of the utility model has a high fiber content, excellent mechanical properties, and excellent thermal insulation performance, and can be applied to a wider range of occasions; the fiber distribution is uniform, there is no fiber exposure, and it is easy to process; the thickness of the sandwich panel can be set between 5-70mm as needed, which can provide more design freedom for the product; the final molded product containing the bio-based polyamide sandwich panel of the utility model can be recycled and reused, and the resource utilization rate is high.

[0053] 3. The bio-based polyamide sandwich panel provided by the utility model has the characteristics of high strength, high modulus, light weight, heat preservation and heat insulation, and is suitable for use as the wall panel of wind turbine blades, building formwork, pallets, refrigerated truck compartments or refrigerated containers. The sandwich panel has strong designability and can reasonably select the thickness and density of the skin and core layer according to actual needs to achieve the best economic effect.

[0054] 4. The upper skin layer, core layer and lower skin layer of the utility model are integrally formed by a double steel belt press. The optimized forming process makes the bonding strength between the skin layer and the core layer higher, and no adhesive or adhesive film is required, which saves costs, optimizes the process, and avoids the generation of unpleasant odors. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic structural diagram of the bio-based polyamide sandwich panel in Example 1 of the utility model.

[0056] Description of reference numerals:

[0057] Epithelium 1

[0058] Core layer 2

[0059] Lower cortex 3 DETAILED DESCRIPTION

[0060] The following will further describe the technical solution of the utility model in combination with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the utility model, and should not be interpreted as limiting the scope of protection of the utility model. All technologies implemented based on the above content of the utility model are included in the scope of protection of the utility model.

[0061] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. 6635 unidirectional prepreg tape and bio-based polyamide 6635 foam boards were purchased from Shanghai Cathay Biotechnology Co., Ltd.

[0062] Examples 1A-1C

[0063] like Figure 1 As shown, a bio-based polyamide sandwich panel comprises an upper skin layer 1, a lower skin layer 3 and a core layer 2 located between the upper skin layer 1 and the lower skin layer 3.

[0064] The upper skin layer 1 and the lower skin layer 3 are made of two layers of continuous glass fiber reinforced bio-based polyamide with a thickness of 0.25 mm. 6635 unidirectional prepreg tape according to [0 / 90] nsIt is made of continuous glass fiber reinforced bio-based polyamide by hot pressing. The volume ratio of the continuous glass fiber in the 6635 unidirectional prepreg tape is 30% vol, and the thickness of the upper skin layer 1 and the lower skin layer 3 are both 0.5 mm.

[0065] The core layer 2 has a thickness of 18 mm and a density of 100 kg / m 3 、150kg / m 3 , 200kg / m 3 Bio-based polyamide 6635 Foam board.

[0066] The upper skin layer 1, the core layer 2 and the lower skin layer 3 are laid out in a predetermined manner and continuously compression molded on a double steel belt compression molding machine. The temperature of the compression molding machine is set to 305°C and the pressure of the compression molding machine is controlled at 2MPa to prepare a bio-based polyamide sandwich panel with a thickness of 19m and 5 layers.

[0067] Examples 2A-2C

[0068] A bio-based polyamide sandwich panel comprises an upper skin layer 1, a lower skin layer 3 and a core layer 2 located between the upper skin layer 1 and the lower skin layer 3.

[0069] The upper skin layer 1 and the lower skin layer 3 are made of 3 layers of continuous glass fiber reinforced bio-based polyamide with a thickness of 0.33 mm. 6635 unidirectional prepreg tape according to [0 / 90 / 0] ns It is made of continuous glass fiber reinforced bio-based polyamide by hot pressing. The volume ratio of the continuous glass fiber in the 6635 unidirectional prepreg tape is 30% vol, and the thickness of the upper skin layer 1 and the lower skin layer 3 are both 1 mm.

[0070] The core layer 2 has a thickness of 18 mm and a density of 100 kg / m 3 , 150kg / m 3 , 200kg / m 3 Bio-based polyamide 6635 Foam board.

[0071] The upper skin layer 1, the core layer 2 and the lower skin layer 3 are laid out in a predetermined manner and continuously compression molded on a double steel belt compression molding machine. The temperature of the compression molding machine is set to 305°C and the pressure of the compression molding machine is controlled at 2MPa to prepare a bio-based polyamide sandwich panel with a thickness of 20m and 7 layers.

[0072] Examples 3A-3C

[0073] A bio-based polyamide sandwich panel comprises an upper skin layer 1, a lower skin layer 3 and a core layer 2 located between the upper skin layer 1 and the lower skin layer 3.

[0074] The upper skin layer 1 and the lower skin layer 3 are made of 4 layers of continuous glass fiber reinforced bio-based polyamide with a thickness of 0.25 mm. 6635 unidirectional prepreg tape according to [0 / 90 / 90 / 0] ns It is made of continuous glass fiber reinforced bio-based polyamide by hot pressing. The volume ratio of the continuous glass fiber in the 6635 unidirectional prepreg tape is 30% vol, and the thickness of the upper skin layer 1 and the lower skin layer 3 are both 1 mm.

[0075] The core layer 2 has a thickness of 18 mm and a density of 100 kg / m 3 , 150kg / m 3 , 200kg / m 3 Bio-based polyamide 6635 Foam board.

[0076] The upper skin layer 1, the core layer 2 and the lower skin layer 3 are laid out in a predetermined manner and continuously molded on a double steel belt molding compound machine. The molding machine temperature is set to 305°C and the molding machine pressure is controlled at 2MPa to prepare a bio-based polyamide sandwich panel with a thickness of 20m and 9 layers.

[0077] The bio-based polyamide sandwich panels obtained in Examples 1A-1C, 2A-2C, and 3A-3C were tested as follows, and the results are shown in Table 1: Among them, the flexural strength and flexural modulus were tested in accordance with GB / T 1456-2005 standard.

[0078] Table 1

[0079]

[0080] As can be seen from Table 1, the bio-based polyamide sandwich panel of the utility model has the characteristics of light weight, high strength, high modulus, etc., and can be used as a wall panel for wind turbine blades, building formwork, pallets, refrigerated truck compartments or refrigerated containers.

[0081] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A bio-based polyamide sandwich panel, characterized in that: The board material comprises an upper skin layer, a lower skin layer and a core layer located between the upper skin layer and the lower skin layer, wherein the upper skin layer and the lower skin layer are each independently composited by at least two layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tapes and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tapes, the core layer adopts a bio-based polyamide foam board, and the upper skin layer, the lower skin layer and the core layer are integrally formed by hot pressing.

2. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The directions of the continuous fibers and continuous fibers, the continuous fiber fabrics and continuous fiber fabrics, or the continuous fibers and continuous fiber fabrics in two adjacent layers of the unidirectional prepreg tapes are crossed at 0-90 degrees.

3. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The upper skin layer and the lower skin layer are each independently composed of at least two layers of continuous fiber reinforced bio-based polyamide unidirectional prepreg tapes and / or continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tapes according to [0 / 90] ns , [90 / 0] ns [0 / 90 / 0] ns , [90 / 0 / 90] ns , [0 / 90 / 90 / 0] ns ,[90 / 0 / 0 / 90] ns , [0 / 90 / 90 / 0 / 90 / 0] ns , [90 / 0 / 90 / 0 / 0 / 90] ns , [0 / 90 / 90 / 0 / 0 / 90 / 90 / 0] ns , [0 / 90 / 0 / 90 / 90 / 0 / 90 / 0] ns or [90 / 0 / 90 / 0 / 0 / 90 / 0 / 90] ns The laminate is formed by hot pressing and compounding using any one of the lamination methods, wherein n is the number of unit cycles and n is an integer greater than 1.

4. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The continuous fiber reinforced bio-based polyamide unidirectional prepreg tape includes continuous carbon fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous glass fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous silicon carbide fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous basalt fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous natural flax fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous aramid fiber reinforced bio-based polyamide unidirectional prepreg tape, continuous semi-aromatic polyamide fiber reinforced bio-based polyamide unidirectional prepreg tape or continuous polyolefin fiber reinforced bio-based polyamide unidirectional prepreg tape.

5. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape includes continuous carbon fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous glass fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous silicon carbide fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous basalt fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous natural flax fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous aramid fiber fabric reinforced bio-based polyamide unidirectional prepreg tape, continuous semi-aromatic polyamide fiber fabric reinforced bio-based polyamide unidirectional prepreg tape or continuous polyolefin fiber fabric reinforced bio-based polyamide unidirectional prepreg tape.

6. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The thickness of the continuous fiber reinforced bio-based polyamide unidirectional prepreg tape is 0.15-5 mm; The thickness of the continuous fiber fabric reinforced bio-based polyamide unidirectional prepreg tape is 0.15-5 mm.

7. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The density of the bio-based polyamide foam board is 80-200 kg / m 3 .

8. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The thickness of the core layer is 5-50 mm.

9. The bio-based polyamide sandwich panel according to claim 1, characterized in that: The thickness of the upper skin layer and the lower skin layer is independently 0.15-10 mm; the thickness of the bio-based polyamide sandwich panel is 5-70 mm.

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