A continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure plate and a preparation method thereof

Abstract

This invention discloses a continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel and its preparation method. The panel comprises a sandwich structure consisting of a continuous fiber fabric as reinforcement, a modified polyphenylene ether thermoplastic resin as the matrix, and polyphenylene ether foam. The modified polyphenylene ether thermoplastic resin includes polyphenylene ether powder, vinyl-modified polyphenylene ether, styrene monomer, flame retardant, and additives. The materials are mixed until they reach a paste-like consistency and then rolled to achieve uniform thickness. The resulting mixed resin sheet, polyphenylene ether foam, and continuous fiber fabric are sequentially layered and then in-situ polymerized and pressed under high temperature and high pressure conditions to obtain the final product. This invention employs in-situ polymerization and pressing molding, increasing the number of units produced per unit time without shortening the polymerization time and ensuring a high degree of polymerization, thereby significantly improving production capacity to meet mass production demands.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel and its preparation method. Background Technology

[0002] Composite foam sandwich structures are widely used for product lightweighting, while also possessing good rigidity and impact resistance. They can be applied to lightweight composite materials requirements in aerospace, automotive, new energy, and rail transit industries. Furthermore, the recyclable and reusable properties of thermoplastic composite materials better meet current environmental protection needs.

[0003] Currently, most commercially available composite foam sandwich structures use thermosetting resin-based composite materials for the outer skin, which are bonded to the foam using adhesives. However, using adhesives for large-area bonding of composite materials and foam often results in low production efficiency, slow adhesive application, and difficulty in ensuring a completely uniform adhesive surface. Furthermore, due to the natural porosity on the foam surface, the effectiveness of the adhesive in penetrating these pores during bonding plays a crucial role in surface bond strength. Additionally, thermosetting resin-based composite materials are often difficult to recycle, especially in sandwich structures where recycling is more complex and costly. Meanwhile, thermoplastic composite materials have higher softening temperatures, far exceeding the temperature resistance of most foams; therefore, foam sandwich structures using thermoplastic composite materials often still rely on adhesive bonding. Summary of the Invention

[0004] The main objective of this invention is to provide a continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel. It uses thermoplastic resin as the matrix component of the composite material in the sandwich structure, maintaining the recyclable and reusable characteristics of thermoplastic composite materials. Unpolymerized resin raw materials are pressed together with fiber fabric and foam as reinforcement and polymerized in situ to form the composite foam sandwich structure. This invention offers the following technical advantages:

[0005] (1) The resin forms a good bonding interface with the fiber surface during the polymerization process, thus having good mechanical properties of the composite material; (2) The resin can easily penetrate the pores on the foam surface during the compression polymerization process, thus achieving good and stable bonding performance between the composite material and the foam surface; (3) The composite material and the bonding are integrally molded, saving implementation steps compared with conventional laminates, avoiding inefficient large-area bonding, improving production efficiency and reducing production costs; (4) The modified polyphenylene ether resin mixture used as the composite material matrix has a polymerization reaction temperature ≤200℃, while polyphenylene ether foam has high temperature resistance, and its performance is not affected at this polymerization temperature; (5) Since both the matrix resin and the foam are polyphenylene ether systems with consistent polymer polarity, the surface bonding force between the composite material and the foam is much higher than that of conventional structural adhesive bonding.

[0006] Another objective of this invention is to provide a method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel, which is simple in process and easy to industrialize.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel, comprising a continuous fiber fabric as reinforcement, a modified polyphenylene ether thermoplastic resin as matrix, and polyphenylene ether foam, comprising, by weight parts: 30-70 parts by weight of continuous fiber fabric, 10-30 parts by weight of polyphenylene ether foam, and 30-70 parts by weight of modified polyphenylene ether thermoplastic resin; wherein:

[0009] The modified polyphenylene ether thermoplastic resin is polymerized from mixed resin flakes, comprising 30-70 parts by weight of polyphenylene ether, 5-20 parts by weight of vinyl-modified polyphenylene ether, 30-70 parts by weight of styrene, 0.5-2 parts by weight of initiator, 1-3 parts by weight of silane coupling agent, 3-16 parts by weight of flame retardant, 0.2-0.6 parts by weight of antioxidant, 0.3-1 parts by weight of heat stabilizer, 0.2-0.4 parts by weight of light stabilizer, and 0.05-0.2 parts by weight of ultraviolet light absorber;

[0010] The continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel is formed by in-situ polymerization and pressing of at least one layer of continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence under high temperature and high pressure conditions.

[0011] Preferably, the material of the continuous fiber fabric is selected from one or more of carbon fiber, glass fiber, and polymer fiber; and / or the form of the continuous fiber fabric includes woven fabric and / or warp-knitted axial fabric.

[0012] Preferably, the polyphenylene oxide foam has a thickness of 0.5–10 mm, is produced by extrusion foaming, and has a foaming density of 50–500 kg / m³. 2 .

[0013] Preferably, the thickness of the modified polyphenylene ether thermoplastic resin is 0.2 to 2 mm.

[0014] Preferably, the vinyl-modified polyphenylene ether comprises, by weight, 30-70 parts of polyphenylene ether, 1-3 parts of acrylic monomers, and 0.5-1 parts of catalyst. The preparation method includes: dissolving polyphenylene ether and acrylic monomers in a solvent and mixing them, purging with nitrogen, slowly adding the catalyst, heating and stirring in an oil bath to carry out the esterification reaction, the reaction temperature being 60-120°C, the reaction time being 2-10 hours, and after the reaction is completed, cooling, filtering, and removing the solvent to obtain the final product.

[0015] A second aspect of the present invention provides a method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel, comprising the following steps:

[0016] (i) Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet light absorber are thoroughly mixed until they form a paste-like consistency. The mixture is then rolled into a uniform thickness of mixed resin sheet.

[0017] (ii) First, preheat the flatbed press, then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and press them at high temperature. Under high temperature and pressure, in-situ polymerization reaction occurs, and the mixture penetrates and wets the surface of the continuous fiber fabric and polyphenylene ether foam. After the process is completed, cool to room temperature and demold to obtain the final product.

[0018] Preferably, the high-temperature pressing molding temperature is 140–210°C, the pressure is 0.5–3 MPa, and the time is 0.5–2 h.

[0019] Preferably, the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel is formed by high-temperature pressing using a flatbed press, including the following steps:

[0020] (1) The upper surface of the steel plate of the flat press is coated with a release agent or a release film is placed in advance, and the cut continuous fiber fabric is placed at a set position above the lower steel plate.

[0021] (2) Lay the mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence on the placed continuous fiber fabric;

[0022] (3) The lower surface of the upper steel plate of the flat press is coated with a release agent or a release film is placed in advance. The upper steel plate is then covered on the continuous fiber fabric on which the mixed resin sheet is finally laid, and aligned with the lower steel plate below.

[0023] (4) The assembled lower steel plate, together with the laminate composed of continuous fiber fabric, mixed resin sheet, foam, mixed resin sheet and continuous fiber fabric, and upper steel plate, are placed into a flat press with a preheating temperature of 140-210℃. After closing the outer door of the press, the mold is closed and high-temperature pressing is performed. The pressing time is 0.5-2 hours and the pressing pressure is 0.5-3 MPa. Vacuum is assisted during the process. After pressing, the pressure is maintained and the temperature is lowered to below 130℃. The vacuum is released, the door is opened and the mold is removed to obtain the product.

[0024] More preferably, in step (4), a multi-layer flatbed press with six openings is used, and the above steps (1)-(4) are repeated until all openings of the multi-layer flatbed press are filled.

[0025] As a preferred embodiment, in step (4), the vacuum is released and the mold is opened, and the lower steel plate, product and upper steel plate of each layer in the multi-layer flat plate press are transferred to a separate multi-layer cold press and cold-pressed together to below 80°C. The number of open layers of the multi-layer cold press is consistent with the number of multi-layer flat plate presses.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The resin raw material used in this invention is a mixed resin sheet, which is easy to operate and can easily penetrate continuous fiber fabrics under high temperature and pressure conditions, thereby achieving a high fiber volume content of >50%, achieving higher mechanical properties, and is suitable for product application scenarios with higher mechanical requirements.

[0028] 2. The molding method of this invention employs in-situ polymerization, during which a reaction occurs at the fiber interface, resulting in high mechanical properties. The mixed resin sheet exhibits uniform thickness and excellent fluidity under high temperature and pressure, easily penetrating and wetting continuous fiber fabrics, and can also penetrate and fill the voids on the foam surface. Furthermore, since both the resin and the foam are polyphenylene ether systems with consistent polymer polarity, they possess excellent interfacial bonding strength between the composite material and the foam.

[0029] 3. This invention directly uses continuous fiber fabric, unpolymerized mixed resin flakes and foam to form a composite sandwich structure board in one step, without the need to first make the composite board and then bond it with the foam. The product has good stability, reduces costs and improves production efficiency.

[0030] 4. The preparation method of the present invention is easy to operate and has uniform thickness of mixed resin flakes, which can be easily automated for production. It can be matched with a multi-layer flat press and can greatly increase the production capacity by increasing the number of pieces produced per unit time without shortening the polymerization time and ensuring a high degree of polymerization, thereby meeting the needs of mass production. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the six-layer open press used in the embodiment. Detailed Implementation

[0032] To more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that other embodiments obtained by those skilled in the art without departing from the concept of the present invention are all within the protection scope of the present invention.

[0033] The specific raw materials used are as follows:

[0034] Polyphenylene ether: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0035] Acrylic acid: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0036] Benzoyl peroxide (BPO): Analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0037] p-Toluenesulfonic acid: analytical grade, produced by Beijing Yancheng Technology Co., Ltd.;

[0038] Styrene: Analytical grade, produced by Beijing Yancheng Technology Co., Ltd.

[0039] γ-Methacryloxypropyltrimethoxysilane (KH-570): Analytical grade, produced by Beijing Yancheng Technology Co., Ltd.

[0040] Aluminum hypophosphite: analytical grade, produced by Beijing Huawirui Chemical Co., Ltd.

[0041] Triphenyl phosphite: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0042] 2-(2-hydroxy-5-methylphenyl)benzotriazole: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0043] Zinc oxide: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0044] Tetraphenyl (bisphenol-A) diphosphate: analytical grade, produced by Beijing Huawirui Chemical Co., Ltd.

[0045] 3,5-Di-tert-butyl-hydroxyphenyl propionate octadecyl ester: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0046] 2,2-Methylenebis(4-methyl-6-tert-butylphenol): Analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0047] 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol: analytical grade, produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0048] Tris(nonylphenyl) phosphite: analytical grade, produced by Shanghai Maclean Biochemical Technology Co., Ltd.

[0049] Distearate thiopropionate: analytical grade, produced by Shanghai Maclean Biochemical Technology Co., Ltd.

[0050] Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate: analytical grade, produced by Shanghai Maclean Biochemical Technology Co., Ltd.

[0051] The following examples illustrate a method for the mass production of continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panels, with the following steps:

[0052] Step 1: Place the cut continuous fiber fabric at the designated position above the lower steel plate. The upper surface of the lower steel plate should be coated with a release agent in advance (for low-cost products without high surface requirements) or a release film should be placed (for products with higher surface requirements). Use a positioning auxiliary device to ensure accurate fabric placement. Place the lower steel plate on the operating table with a conveyor belt, and the fabric will be automatically picked up and placed.

[0053] Step 2: Lay the mixed resin sheet on the placed continuous fiber fabric. The weight of the sheet is calculated in advance according to the actual needs of the product. Select the automated operation and transport the lower steel plate carrying the continuous fiber fabric to the sheet laying robot operation area via conveyor belt. The robot will then lay the mixed resin sheet.

[0054] Step 3: Lay polyphenylene ether foam on the prepared mixed resin sheet, and use a positioning auxiliary device to ensure that the fabric is laid in an accurate position.

[0055] Step 4: Lay the mixed resin sheets on the placed foam. The weight of the sheets should be calculated in advance according to the actual needs of the product. Automated operation is selected, and the mixed resin sheets are laid by a robot arm.

[0056] Step 5: Lay out continuous fiber fabric on the mixed resin sheet, using a positioning aid to ensure accurate fabric placement.

[0057] Step 6: Cover the final laid continuous fiber fabric with the upper steel plate, aligning it with the lower steel plate below. Apply a release agent or place a release film on the lower surface of the upper steel plate beforehand. Select automated operation, and transport the lower steel plate, containing the laid continuous fiber fabric, mixed resin sheets, foam, mixed resin sheets, and continuous fiber fabric, to the upper steel plate storage area via conveyor belt for automatic gripping and placement.

[0058] Step 7: Combine the lower steel plate, continuous fiber fabric, mixed resin sheet, foam, and upper steel plate together and transfer them into a flatbed press preheated to 140-210°C. Select automated operation and transport them to the flatbed press via conveyor belt. Since the polymerization time of the mixed resin sheet is at least 30 minutes, for mass production, it is necessary to shorten the production time per unit without reducing the polymerization time to ensure a high degree of polymerization. Therefore, a multi-layer flatbed press is used for pressing. For example, a 6-layer open flatbed press (…) Figure 1 Repeat the above steps 6 times until all openings of the multi-layer flatbed press are filled. In the cyclic operation of the integrated automated production line, the shortest production time per piece after amortization is theoretically 5 minutes. If more layers of openings are added, the amortized production time per piece can be further shortened to achieve higher production efficiency.

[0059] Step 8: After all the lower steel plates, continuous fiber fabric, mixed resin sheets, foam, mixed resin sheets, continuous fiber fabric and upper steel plates are combined and put into the preheated press, the mold is closed and pressed after the outer door of the press is closed. The pressing time is 0.5 to 2 hours (depending on the product performance requirements and production efficiency), and the pressing pressure is 0.5 to 3 MPa. Vacuuming is assisted during the process to improve product quality. The continuous fiber fabric, mixed resin sheets and foam are pressed at high temperature and polymerized in situ to form the product.

[0060] Step 9: After the pressing time is over, continue to maintain the pressure and cool down to below 130°C, then release the vacuum and open the door to remove the mold.

[0061] For mass production, the multi-layer flat press is kept at a constant preheating temperature of 140–210°C. After the pressing time is completed, the vacuum is immediately released and the mold is opened. The lower steel plates, products, and upper steel plates from each layer of the multi-layer flat press are transferred to a separate multi-layer cold press for cold pressing to below 80°C. The number of open layers in the cold press is consistent with the number of multi-layer flat presses. After pressing, the lower steel plates, products, and upper steel plates are transferred to the operating table, the upper steel plates are removed, and then the products are taken out. This step is automated. The lower steel plates, products, and upper steel plates are transported by conveyor belt to the upper steel plate storage area, where the upper steel plates are automatically grabbed, unloaded, and repositioned. Then, the products are automatically grabbed, unloaded, and transferred for storage. Finally, the lower steel plates are transported back to the starting position of the lower steel plates in step 1 by conveyor belt, ready for the next round of automated cycle operation.

[0062] Example 1

[0063] This embodiment proposes a continuous fiber reinforced polyphenylene ether thermoplastic composite foam sandwich structure panel, which consists of a surface material composed of a continuous fiber fabric as the reinforcement and a modified polyphenylene ether resin as the matrix, and a polyphenylene ether extruded sheet as the foam core material. The modified polyphenylene ether thermoplastic resin is polymerized from a mixed resin material, wherein: 55 parts by weight of polyphenylene ether, 5 parts by weight of vinyl-modified polyphenylene ether, 50 parts by weight of styrene, 2 parts by weight of initiator, 3 parts by weight of silane coupling agent, 7 parts by weight of flame retardant, 0.5 parts by weight of antioxidant, 0.7 parts by weight of heat stabilizer, 0.3 parts by weight of light stabilizer, and 0.2 parts by weight of ultraviolet light absorber.

[0064] The initiator is BPO; the silane coupling agent is KH-570; the flame retardant is aluminum hypophosphite; the antioxidant is octadecyl 3,5-di-tert-butyl-hydroxyphenylpropionate; the heat stabilizer is triphenyl phosphite; the light stabilizer is 2-(2-hydroxy-5-methylphenyl)benzotriazole; and the ultraviolet absorber is zinc oxide.

[0065] The preparation steps of the above-mentioned foam sandwich structure panel are as follows: Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet absorber are thoroughly mixed until they reach a paste-like consistency. This mixture is then rolled into a uniform thickness of mixed resin sheet. A flatbed press is preheated. Continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, and the remaining mixed resin sheet are sequentially laid out and then subjected to high-temperature pressing. Under high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization, simultaneously penetrating and wetting the continuous fiber fabric and foam surface. After high-temperature pressing, the mixture is cooled to room temperature and demolded to obtain the composite sandwich structure panel. The high-temperature pressing temperature is 200℃, the pressure is 2MPa, and the time is 1h. The surface layer thickness of the composite material is 1mm, the core layer polyphenylene ether foam is 3mm, and the foam density is 500kg / m³.3 .

[0066] Example 2

[0067] This embodiment proposes a continuous fiber reinforced polyphenylene ether thermoplastic composite foam sandwich structure panel, which consists of a surface material composed of a continuous fiber fabric as the reinforcement and a modified polyphenylene ether resin as the matrix, and a polyphenylene ether extruded sheet as the foam core material. The modified polyphenylene ether thermoplastic resin is polymerized from a mixed resin material, wherein there are 55 parts by weight of polyphenylene ether, 5 parts by weight of vinyl-modified polyphenylene ether, 50 parts by weight of styrene, 2 parts by weight of initiator, 3 parts by weight of silane coupling agent, 7 parts by weight of flame retardant, 0.5 parts by weight of antioxidant, 0.7 parts by weight of heat stabilizer, 0.3 parts by weight of light stabilizer, and 0.2 parts by weight of ultraviolet light absorber.

[0068] The initiator is BPO; the silane coupling agent is KH-570; the flame retardant is aluminum hypophosphite; the antioxidant is octadecyl 3,5-di-tert-butyl-hydroxyphenylpropionate; the heat stabilizer is triphenyl phosphite; the light stabilizer is 2-(2-hydroxy-5-methylphenyl)benzotriazole; and the ultraviolet absorber is zinc oxide.

[0069] The preparation steps of the above-mentioned foam sandwich structure panel are as follows: Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet absorber are thoroughly mixed until a paste-like consistency is achieved. This mixture is then rolled into a uniform thickness of mixed resin sheet. A flatbed press is preheated. Continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, and the remaining mixed resin sheet are sequentially laid out and then subjected to high-temperature pressing. Under high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization, simultaneously penetrating and wetting the continuous fiber fabric and foam surface. After high-temperature pressing, the mixture is cooled to room temperature and demolded to obtain the composite sandwich structure panel. The high-temperature pressing temperature is 200℃, the pressure is 2MPa, and the time is 1h. The surface layer thickness of the composite material is 1mm, the core layer polyphenylene ether extruded foam is 3mm thick, and the foam density is 300kg / m³. 3 .

[0070] Example 3

[0071] This embodiment proposes a continuous fiber reinforced polyphenylene ether thermoplastic composite foam sandwich structure panel, which consists of a surface material composed of a continuous fiber fabric as the reinforcement and a modified polyphenylene ether resin as the matrix, and a polyphenylene ether extruded sheet as the foam core material. The modified polyphenylene ether thermoplastic resin is polymerized from a mixed resin material, wherein there are 55 parts by weight of polyphenylene ether, 5 parts by weight of vinyl-modified polyphenylene ether, 50 parts by weight of styrene, 2 parts by weight of initiator, 3 parts by weight of silane coupling agent, 7 parts by weight of flame retardant, 0.5 parts by weight of antioxidant, 0.7 parts by weight of heat stabilizer, 0.3 parts by weight of light stabilizer, and 0.2 parts by weight of ultraviolet light absorber.

[0072] The initiator is BPO; the silane coupling agent is KH-570; the flame retardant is aluminum hypophosphite; the antioxidant is octadecyl 3,5-di-tert-butyl-hydroxyphenylpropionate; the heat stabilizer is triphenyl phosphite; the light stabilizer is 2-(2-hydroxy-5-methylphenyl)benzotriazole; and the ultraviolet absorber is zinc oxide.

[0073] The preparation steps of the above-mentioned foam sandwich structure panel are as follows: Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet absorber are thoroughly mixed until a paste-like consistency is achieved. This mixture is then rolled into a uniform thickness of mixed resin sheet. A flatbed press is preheated. Continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, and the remaining mixed resin sheet are sequentially laid out and then subjected to high-temperature pressing. Under high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization, simultaneously penetrating and wetting the continuous fiber fabric and foam surface. After high-temperature pressing, the mixture is cooled to room temperature and demolded to obtain the composite sandwich structure panel. The high-temperature pressing temperature is 220℃, the pressure is 2MPa, and the time is 1 hour. The surface layer thickness of the composite material is 1mm, the core layer polyphenylene ether extruded foam is 3mm thick, and the foam density is 300kg / m³. 3 .

[0074] Example 4

[0075] This embodiment proposes a continuous fiber reinforced polyphenylene ether thermoplastic composite foam sandwich structure panel, which consists of a surface material composed of a continuous fiber fabric as the reinforcing body and a modified polyphenylene ether resin as the matrix, and a polyphenylene ether extruded sheet as the foam core material. The modified polyphenylene ether thermoplastic resin is polymerized from a mixed resin material, wherein there are 55 parts by weight of polyphenylene ether, 5 parts by weight of vinyl modified polyphenylene ether, 50 parts by weight of styrene, 2 parts by weight of initiator, 3 parts by weight of silane coupling agent, 7 parts by weight of flame retardant, 0.5 parts by weight of antioxidant, 0.7 parts by weight of heat stabilizer, 0.3 parts by weight of light stabilizer, and 0.2 parts by weight of ultraviolet light absorber.

[0076] The initiator is BPO; the silane coupling agent is KH-570; the flame retardant is aluminum hypophosphite; the antioxidant is octadecyl 3,5-di-tert-butyl-hydroxyphenylpropionate; the heat stabilizer is triphenyl phosphite; the light stabilizer is 2-(2-hydroxy-5-methylphenyl)benzotriazole; and the ultraviolet absorber is zinc oxide.

[0077] The preparation steps of the above-mentioned foam sandwich structure panel are as follows: Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet absorber are thoroughly mixed until they reach a paste-like consistency. This mixture is then rolled into a uniform thickness of mixed resin sheet. A flatbed press is preheated. Continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, and the remaining mixed resin sheet are sequentially laid out and then subjected to high-temperature pressing. Under high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization, simultaneously penetrating and wetting the continuous fiber fabric and foam surface. After high-temperature pressing, the mixture is cooled to room temperature and demolded to obtain the composite sandwich structure panel. The high-temperature pressing temperature is 200℃, the pressure is 2MPa, and the time is 1h. The surface layer thickness of the composite material is 2mm, the core layer polyphenylene ether extruded foam is 2mm thick, and the foam density is 300kg / m³. 3 .

[0078] Comparative Example

[0079] Compared with Example 1, this comparative example does not use in-situ polymerization to produce thermoplastic composite foam sandwich structure panels, wherein the materials are: 55 parts by weight of polyphenylene ether, 55 parts by weight of polystyrene, 2 parts by weight of initiator, 3 parts by weight of silane coupling agent, 7 parts by weight of flame retardant, 0.5 parts by weight of antioxidant, 0.7 parts by weight of heat stabilizer, 0.3 parts by weight of light stabilizer, and 0.2 parts by weight of ultraviolet light absorber.

[0080] The initiator is BPO; the silane coupling agent is KH-570; the flame retardant is aluminum hypophosphite; the antioxidant is octadecyl 3,5-di-tert-butyl-hydroxyphenylpropionate; the heat stabilizer is triphenyl phosphite; the light stabilizer is 2-(2-hydroxy-5-methylphenyl)benzotriazole; and the ultraviolet absorber is zinc oxide.

[0081] The above materials are pressed into sheets using a flat vulcanizing machine, then alternately laid with continuous fiber fabric, with polyphenylene ether extruded foam board added in between as a core layer. The high-temperature pressing molding process is carried out at 200℃, 2MPa, and 1 hour. The composite material has a surface layer thickness of 1mm, a core layer of 3mm thick polyphenylene ether extruded foam, and a foam density of 300kg / m³. 3 .

[0082] Table 1

[0083]

[0084]

[0085] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel, characterized in that, It is a sandwich structure composed of a continuous fiber fabric as reinforcement, a modified polyphenylene ether thermoplastic resin as matrix, and polyphenylene ether foam, wherein the continuous fiber fabric comprises 30-70 parts by weight, the polyphenylene ether foam comprises 10-30 parts by weight, and the modified polyphenylene ether thermoplastic resin comprises 30-70 parts by weight; wherein: The modified polyphenylene ether thermoplastic resin is polymerized from mixed resin flakes, which include 30-70 parts by weight of polyphenylene ether, 5-20 parts by weight of vinyl-modified polyphenylene ether, 30-70 parts by weight of styrene, 0.5-2 parts by weight of initiator, 1-3 parts by weight of silane coupling agent, 3-16 parts by weight of flame retardant, 0.2-0.6 parts by weight of antioxidant, 0.3-1 parts by weight of heat stabilizer, 0.2-0.4 parts by weight of light stabilizer, and 0.05-0.2 parts by weight of ultraviolet light absorber. The continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel is formed by in-situ polymerization and pressing of continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence under high temperature and high pressure conditions, with a temperature of 140~210 ℃ and a pressure of 0.5~3 MPa. The vinyl-modified polyphenylene ether comprises, by weight, 30-70 parts of polyphenylene ether, 1-3 parts of acrylic monomers, and 0.5-1 parts of catalyst. The preparation method includes: dissolving polyphenylene ether and acrylic monomers in a solvent and mixing them, purging with nitrogen, slowly adding the catalyst, heating and stirring in an oil bath to carry out the esterification reaction, the reaction temperature being 60-120℃, the reaction time being 2-10h, and after the reaction is completed, cooling, filtering, and removing the solvent to obtain the product.

2. The continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 1, characterized in that, The material of the continuous fiber fabric is selected from one or more of carbon fiber, glass fiber, and polymer fiber; and / or the form of the continuous fiber fabric includes woven fabric and / or warp-knitted axial fabric.

3. The continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 1, characterized in that, The polyphenylene oxide foam has a thickness of 0.5~10mm, is produced by extrusion foaming process, and has a foaming density of 50~500kg / m³. 3 .

4. The continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 1, characterized in that, The thickness of the modified polyphenylene ether thermoplastic resin is 0.2~2mm.

5. A method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to any one of claims 1 to 4, characterized in that, Includes the following steps: (i) Polyphenylene ether, vinyl-modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet absorber are thoroughly mixed until they form a paste-like consistency. The mixture is then rolled into uniformly thick mixed resin sheets. (ii) First, preheat the flatbed press, then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and press them at high temperature. Under high temperature and pressure, in-situ polymerization reaction occurs, and the mixture penetrates and wets the surface of the continuous fiber fabric and polyphenylene ether foam. After the process is completed, cool to room temperature and demold to obtain the final product.

6. The method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 5, characterized in that, High-temperature pressing and molding using a flatbed press includes the following steps: (1) The upper surface of the steel plate of the flat press is coated with a release agent or a release film is placed in advance, and the cut continuous fiber fabric is placed at the set position above the lower steel plate. (2) Lay the mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence on the placed continuous fiber fabric; (3) The lower surface of the upper steel plate of the flat press is coated with a release agent or a release film is placed in advance, the upper steel plate is covered on the continuous fiber fabric and aligned with the lower steel plate below; (4) The assembled lower steel plate, the laminate composed of continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric and the upper steel plate are combined and moved into a flat plate press with a preheating temperature of 140~210 ℃. (5) After closing the outer door of the press, close the mold and press it at high temperature. The pressing time is 0.5~2 h and the pressing pressure is 0.5~3 MPa. Vacuum is assisted during the process. After pressing, maintain the pressure and cool down to below 130℃. Release the vacuum, open the door and remove the mold to obtain the product.

7. The method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 6, characterized in that, In step (5), a multi-layer flatbed press with six openings is used, and steps (1)-(4) above are repeated until all openings of the multi-layer flatbed press are filled.

8. The method for preparing the continuous fiber-reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure panel according to claim 7, characterized in that, In step (5), the vacuum is released and the mold is opened. The lower steel plate, product and upper steel plate of each layer in the multi-layer flat plate press are transferred to a separate multi-layer cold press and cold-pressed together to below 80°C. The number of open layers of the multi-layer cold press is consistent with the number of open layers of the multi-layer flat plate press.

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