Continuous fiber reinforced modified polyphenyl ether thermoplastic composite material foam sandwich structure plate and preparation method thereof

Abstract

The invention discloses a continuous fiber reinforced modified polyphenyl ether thermoplastic composite material foam sandwich structure plate and a preparation method thereof, and the continuous fiber reinforced modified polyphenyl ether thermoplastic composite material foam sandwich structure plate is a sandwich structure composed of a continuous fiber fabric as a reinforcement, modified polyphenyl ether thermoplastic resin as a matrix and polyphenyl ether foam, the modified polyphenyl ether thermoplastic resin comprises polyphenyl ether powder, vinyl modified polyphenyl ether, a styrene monomer, a flame retardant and an auxiliary agent, the materials are uniformly mixed to be in a daub shape and then are rolled until the thickness is uniform, and the obtained mixed resin material sheet, polyphenyl ether foam and the continuous fiber fabric are sequentially paved and then are subjected to in-situ polymerization pressing under the conditions of high temperature and high pressure to obtain the composite material. According to the method, in-situ polymerization compression molding is adopted, the number of production pieces in unit time is increased under the conditions that polymerization time is not shortened and the high polymerization degree is guaranteed, the productivity is improved to a large extent, and therefore the mass production requirement is met.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board and a preparation method thereof. Background Art

[0002] Composite foam core sandwich structures are widely used in lightweight products. They have good stiffness and impact resistance and can be applied to lightweight composite materials in aviation, automobiles, new energy, rail transit, etc. At the same time, the recyclable and reusable properties of thermoplastic composite materials are more in line with current environmental protection needs.

[0003] At present, the outer skin of composite foam sandwich structures on the market is mostly based on thermosetting resin-based composite materials, which are bonded to the foam by gluing. However, the use of gluing to bond large areas of composite materials to foam often leads to low production efficiency, slow gluing over large areas, and it is difficult to ensure that the entire bonding surface is completely uniform. In addition, due to the natural gaps on the foam surface, whether the glue during the bonding process can effectively penetrate the surface gaps plays a key role in the surface bonding strength. In addition, thermosetting resin-based composite materials are often difficult to recycle due to their characteristics, especially in sandwich structures, where recycling is more complicated and costly, while the softening point temperature of thermoplastic composite materials is relatively high, far exceeding the temperature resistance of most foams. For thermoplastic composite foam sandwich structures, gluing is often still used. Summary of the invention

[0004] The main purpose of the present invention is to provide a continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board, which uses thermoplastic resin as the matrix part of the composite material in the sandwich structure, maintains the recyclable and reusable characteristics of the thermoplastic composite material, and uses unpolymerized resin raw materials together with fiber fabrics and foams as reinforcements to press and polymerize in situ to form a composite foam sandwich structure, which has the following technical advantages:

[0005] (1) The resin forms a good bonding interface with the fiber surface during the polymerization process, thereby having better mechanical properties of the composite material; (2) The resin can easily penetrate the gaps on the foam surface during the pressing and polymerization process, thereby achieving better and more stable bonding performance between the composite material and the foam surface; (3) The composite material and the bonding are integrally formed, which saves implementation steps compared to conventional laminates, avoids inefficient large-area bonding, improves production efficiency, and reduces production costs; (4) The modified polyphenylene ether resin mixed raw material used as the composite material matrix has a polymerization reaction temperature of ≤200°C, and the polyphenylene ether foam has high temperature resistance, and the performance of the foam is not affected at this polymerization temperature; (5) Since the matrix resin and the foam are both 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 object of the present invention is to provide a method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board, which has a simple process and is easy for industrial production.

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

[0008] The first aspect of the present invention provides a continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board, which is a sandwich structure composed of a continuous fiber fabric as a reinforcement, a modified polyphenylene ether thermoplastic resin as a matrix, and a polyphenylene ether foam, and comprises, by weight: 30 to 70 parts by weight of the continuous fiber fabric, 10 to 30 parts by weight of the polyphenylene ether foam, and 30 to 70 parts by weight of the modified polyphenylene ether thermoplastic resin; wherein:

[0009] The modified polyphenylene ether thermoplastic resin is polymerized from mixed resin flakes, and includes 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 board is formed by sequentially stacking at least one layer of continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric, and in-situ polymerization and pressing 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 ether foam has a thickness of 0.5 to 10 mm and is formed by extrusion foaming process with a foaming density of 50 to 500 kg / m 2 .

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

[0014] Preferably, the vinyl-modified polyphenylene ether comprises, by weight, 30 to 70 parts by weight of polyphenylene ether, 1 to 3 parts by weight of acrylic monomer and 0.5 to 1 part by weight of catalyst. The preparation method comprises: dissolving polyphenylene ether and acrylic monomer in a solvent and mixing evenly, passing nitrogen gas for protection, slowly dropping the catalyst, heating and stirring in an oil bath for esterification reaction, the reaction temperature is 60 to 120° C., the reaction time is 2 to 10 hours, and cooling, filtering and removing the solvent after the reaction is completed to obtain the product.

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

[0016] (i) fully stirring and mixing polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer and ultraviolet light absorber until they are in a clay state, and rolling them into a mixed resin sheet with uniform thickness;

[0017] (ii) Preheating a flat press, sequentially laying the continuous fiber fabric, the mixed resin sheet, the polyphenylene ether foam, the mixed resin sheet and the continuous fiber fabric, and then subjecting them to high-temperature pressing and molding, wherein an in-situ polymerization reaction occurs under the conditions of high temperature and pressure, while the surfaces of the continuous fiber fabric and the polyphenylene ether foam are infiltrated and soaked, and after completion, the reaction is cooled to room temperature and demolded to obtain the product.

[0018] Preferably, the high temperature pressing molding is performed at a temperature of 140 to 210° C., a pressure of 0.5 to 3 MPa, and a time of 0.5 to 2 h.

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

[0020] (1) A release agent is applied to the upper surface of the lower steel plate of the flat press in advance or an isolation film is placed thereon, and the cut continuous fiber fabric is placed at a predetermined position above the lower steel plate;

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

[0022] (3) A release agent is applied to the lower surface of the upper steel plate of the flat press in advance or an isolation film is placed thereon, and the upper steel plate is 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, the laminate composed of continuous fiber fabric, mixed resin sheet, 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°C. After closing the outer door of the press, the mold is closed for high-temperature pressing. The pressing time is 0.5-2h and the pressing pressure is 0.5-3MPa. The process is assisted by vacuuming. After the pressing is completed, the pressure is maintained and the temperature is lowered to below 130°C. The vacuum is released and the door is opened to remove the mold.

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

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

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The resin raw material used in the present invention is a mixed resin flake material, 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% and achieving higher mechanical properties, and is suitable for product application scenarios with higher mechanical requirements.

[0028] 2. The molding method of the present invention adopts an in-situ polymerization method. During the polymerization process, there is a reaction with the fiber interface, which has high mechanical properties. The mixed resin sheet has uniform thickness and good fluidity under high temperature and pressure. It is easy to penetrate and infiltrate the continuous fiber fabric, and can penetrate and fill the gaps on the foam surface. In addition, since the resin and the foam are both polyphenylene ether systems, they have consistent polymer polarity and have excellent composite material and foam interface bonding.

[0029] 3. The present invention directly uses continuous fiber fabrics, unpolymerized mixed resin sheets and foam to form a composite sandwich structure board in one step, without the need to first make a 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 realize automated production due to the easy operation and thickness uniformity of the mixed resin sheet, and can be matched with a multi-layer flat press. The production capacity can be greatly improved 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the six-layer opening press used in the embodiment. DETAILED DESCRIPTION

[0032] In order to more fully understand and demonstrate the technical solutions, purposes and advantages of the present invention, the technical effects produced by the present invention are further described in detail and completely in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all. It should be pointed out that for ordinary technicians in this field, other embodiments obtained without departing from the concept of the present invention all belong to the protection scope of the present invention.

[0033] The 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 Huawei Ruike 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 Huawei Ruike Chemical Co., Ltd.;

[0045] 3,5-di-tert-butyl-hydroxyphenylpropionic acid 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-methyl-phenol: 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] Distearyl 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 mass production method of the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board in the following embodiment comprises the following steps:

[0052] Step 1: Place the cut continuous fiber fabric on the set 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 an isolation film (for products with higher surface requirements). Use a positioning auxiliary device to ensure the accurate placement of the fabric. Place the lower steel plate on an operating table with a conveyor belt, and automatically grab and place the fabric.

[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 automated operation and transport the lower steel plate carrying the continuous fiber fabric to the sheet laying robot operation area via a conveyor belt. The robot will lay the mixed resin sheet.

[0054] Step 3: lay polyphenylene ether foam on the placed mixed resin sheet, and use a positioning auxiliary device to ensure the accurate placement of the fabric.

[0055] Step 4: Place the mixed resin sheet on the placed foam. The weight of the sheet is calculated in advance based on the actual needs of the product. Select automated operation and use a robot to place the mixed resin sheet.

[0056] Step 5: Lay the continuous fiber fabric on the mixed resin sheet, and use a positioning auxiliary device to ensure the accurate placement of the fabric.

[0057] Step 6: Cover the upper steel plate on the finally laid continuous fiber fabric and align it with the lower steel plate below. Apply a release agent or place an isolation film on the lower surface of the upper steel plate in advance. Select the automated operation and transport the lower steel plate carrying the laid continuous fiber fabric, mixed resin sheet, foam, mixed resin sheet and continuous fiber fabric to the storage area of ​​the upper steel plate via a conveyor belt to automatically grab and place the upper steel plate.

[0058] Step 7: Move the lower steel plate, continuous fiber fabric, mixed resin sheet, foam, mixed resin sheet, continuous fiber fabric together with the upper steel plate into a flat press with a preheating temperature of 140-210°C, and select automated operation to transport them to the flat press via a conveyor belt. Since the polymerization time of the mixed resin sheet is at least 30 minutes or more, the production time of a single piece needs to be shortened for mass production, while the polymerization time should not be reduced to ensure a high degree of polymerization. A multi-layer flat press is used for pressing. For example, a 6-layer open flat press ( Figure 1 ), repeat the above steps 6 times until all the openings of the multi-layer flat press are filled. In the cycle operation of the integrated automated production line, the theoretically shortest production time of a single piece after average production is 5 minutes. If more layers of openings are added, the average production time of a single piece can be further shortened to achieve higher production efficiency.

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

[0061] For mass production, the multi-layer flat press is kept at a preheating temperature of 140-210°C. After the pressing time is over, the vacuum is directly removed and the door is opened to remove the mold. The lower steel plate, product, and upper steel plate combination of each layer in the multi-layer flat press are transferred to a separate multi-layer cold press and cold pressed together to below 80°C. The number of opening layers of the multi-layer cold press is consistent with the number of multi-layer flat presses; the lower steel plate, product, and upper steel plate combination after pressing are transferred to the operating table and the upper steel plate is removed, and then the product is taken out. This step selects automated operation, and the lower steel plate, product, and upper steel plate combination are transported to the upper steel plate storage area by a conveyor belt, and the upper steel plate is automatically grabbed and unloaded and re-placed for storage, and then the product is automatically grabbed and unloaded and transferred for storage. Finally, the lower steel plate is transported back to the starting position of the lower steel plate in step 1 by a conveyor belt to wait for the next round of automated cycle operation.

[0062] Example 1

[0063] The present embodiment proposes a continuous fiber reinforced polyphenylene ether thermoplastic composite foam sandwich structure panel, which comprises a surface layer material of a continuous fiber fabric as a reinforcement and a modified polyphenylene ether resin as a matrix, and a polyphenylene ether extruded sheet as a foam core layer 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 an initiator, 3 parts by weight of a silane coupling agent, 7 parts by weight of a flame retardant, 0.5 parts by weight of an antioxidant, 0.7 parts by weight of a heat stabilizer, 0.3 parts by weight of a light stabilizer, and 0.2 parts by weight of an ultraviolet light absorber.

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

[0065] The preparation steps of the above foam sandwich structure board are as follows: polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, ultraviolet light absorber are fully stirred and mixed until it is in a clay state, and then rolled into a mixed resin sheet with uniform thickness. First, preheat the flat press, and then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and then perform high-temperature pressing and molding. Under the conditions of high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization reaction, and at the same time penetrates and infiltrates the continuous fiber fabric and the foam surface. After the high-temperature pressing and molding is completed, it is cooled to room temperature and demolded to obtain a composite sandwich structure board. The high-temperature pressing and molding temperature is 200°C, the pressure is 2MPa, and the time is 1h. The surface thickness of the composite material is 1mm, the core layer polyphenylene ether foam is 3mm, and the foam density is 500kg / m3 .

[0066] Example 2

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

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

[0069] The preparation steps of the above foam sandwich structure board are as follows: polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, ultraviolet light absorber are fully stirred and mixed until it is in a clay state, and then rolled into a mixed resin sheet with uniform thickness. First, preheat the flat press, and then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and then perform high-temperature pressing and molding. Under the conditions of high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization reaction, and at the same time penetrates and infiltrates the continuous fiber fabric and the foam surface. After the high-temperature pressing and molding is completed, it is cooled to room temperature and demolded to obtain a composite sandwich structure board. The temperature of high-temperature pressing and molding is 200°C, the pressure is 2MPa, the time is 1h, the surface thickness of the composite material is 1mm, the core layer polyphenylene ether extruded foam is 3mm, and the foam density is 300kg / m 3 .

[0070] Example 3

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

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

[0073] The preparation steps of the above-mentioned foam sandwich structure board are as follows: polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, and ultraviolet light absorber are fully stirred and mixed until they are in a clay state, and then rolled into a mixed resin sheet with uniform thickness. First, preheat the flat press, and then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and then perform high-temperature pressing and molding. Under high temperature and pressure conditions, the mixed resin sheet undergoes in-situ polymerization reaction, and at the same time penetrates and infiltrates the continuous fiber fabric and the foam surface. After the high-temperature pressing and molding is completed, it is cooled to room temperature and demolded to obtain a composite sandwich structure board. The temperature of high-temperature pressing and molding is 220°C, the pressure is 2MPa, and the time is 1h. The surface thickness of the composite material is 1mm, the core layer polyphenylene ether extruded foam is 3mm, and the foam density is 300kg / m 3 .

[0074] Example 4

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

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

[0077] The preparation steps of the above-mentioned foam sandwich structure board are as follows: polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer, ultraviolet light absorber are fully stirred and mixed until it is in a clay state, and then rolled into a mixed resin sheet with uniform thickness. First, preheat the flat press, and then lay the continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric in sequence and then perform high-temperature pressing and molding. Under the conditions of high temperature and pressure, the mixed resin sheet undergoes in-situ polymerization reaction, and at the same time penetrates and infiltrates the continuous fiber fabric and the foam surface. After the high-temperature pressing and molding is completed, it is cooled to room temperature and demolded to obtain a composite sandwich structure board. The temperature of high-temperature pressing and molding is 200°C, the pressure is 2MPa, the time is 1h, the surface thickness of the composite material is 2mm, the core layer polyphenylene ether extruded foam is 2mm, and the foam density is 300kg / m 3 .

[0078] Comparative Example

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

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

[0081] The above materials are pressed into sheets by a flat vulcanizer and then alternately covered with continuous fiber fabrics. Polyphenylene ether extruded foam sheets are added in the middle as the core layer. The high-temperature pressing temperature is 200°C, the pressure is 2MPa, and the time is 1h. The surface thickness of the composite material is 1mm, the core layer polyphenylene ether extruded foam is 3mm, and the foam density is 300kg / m 3 .

[0082] Table 1

[0083]

[0084]

[0085] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board, characterized in that: The sandwich structure is composed of continuous fiber fabric as a reinforcement, modified polyphenylene ether thermoplastic resin as a matrix and polyphenylene ether foam, which comprises, by weight: 30 to 70 parts by weight of continuous fiber fabric, 10 to 30 parts by weight of polyphenylene ether foam and 30 to 70 parts by weight of modified polyphenylene ether thermoplastic resin; wherein: The modified polyphenylene ether thermoplastic resin is polymerized from mixed resin flakes, and includes 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 board is formed by sequentially stacking at least one layer of continuous fiber fabric, mixed resin sheet, polyphenylene ether foam, mixed resin sheet and continuous fiber fabric, and in-situ polymerization and pressing under high temperature and high pressure conditions.

2. The continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board 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 thickness of the polyphenylene ether foam is 0.5-10 mm, and it is made by extrusion foaming process, and the foaming density is 50-500 kg / m 2 .

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 0.2-2 mm.

5. The continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to claim 1, characterized in that: The vinyl modified polyphenylene ether comprises, by weight, 30 to 70 parts by weight of polyphenylene ether, 1 to 3 parts by weight of acrylic monomer and 0.5 to 1 part by weight of catalyst. The preparation method comprises: dissolving polyphenylene ether and acrylic monomer in a solvent and mixing them evenly, passing nitrogen gas for protection, slowly dropping the catalyst, heating and stirring in an oil bath for esterification reaction, the reaction temperature is 60 to 120° C., the reaction time is 2 to 10 hours, and cooling, filtering and removing the solvent after the reaction is completed to obtain the vinyl modified polyphenylene ether.

6. The method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to any one of claims 1 to 5, characterized in that: The following steps are involved: (i) fully stirring and mixing polyphenylene ether, vinyl modified polyphenylene ether, styrene, initiator, silane coupling agent, flame retardant, antioxidant, heat stabilizer, light stabilizer and ultraviolet light absorber until they are in a clay state, and rolling them into a mixed resin sheet with uniform thickness; (ii) Preheating a flat press, sequentially laying the continuous fiber fabric, the mixed resin sheet, the polyphenylene ether foam, the mixed resin sheet and the continuous fiber fabric, and then subjecting them to high-temperature pressing and molding, wherein an in-situ polymerization reaction occurs under the conditions of high temperature and pressure, while the surfaces of the continuous fiber fabric and the polyphenylene ether foam are infiltrated and soaked, and after completion, the reaction is cooled to room temperature and demolded to obtain the product.

7. The method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to claim 6, characterized in that: The high temperature pressing molding is performed at a temperature of 140 to 210° C., a pressure of 0.5 to 3 MPa, and a time of 0.5 to 2 h.

8. The method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to claim 6, characterized in that: The high temperature pressing and molding is performed by a flat plate press, comprising the following steps: (1) A release agent is applied to the upper surface of the lower steel plate of the flat press in advance or an isolation film is placed thereon, and the cut continuous fiber fabric is placed at a predetermined position above the lower steel plate; (2) placing a mixed resin sheet, polyphenylene ether foam, a mixed resin sheet and a continuous fiber fabric in sequence on the placed continuous fiber fabric; (3) A release agent is applied to the lower surface of the upper steel plate of the flat press in advance or an isolation film is placed thereon, and the upper steel plate is covered on the continuous fiber fabric on which the mixed resin sheet is finally laid, and aligned with the lower steel plate below; (4) The assembled lower steel plate, the laminate composed of continuous fiber fabric, mixed resin sheet, 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°C. After closing the outer door of the press, the mold is closed for high-temperature pressing. The pressing time is 0.5-2h and the pressing pressure is 0.5-3MPa. The process is assisted by vacuuming. After the pressing is completed, the pressure is maintained and the temperature is lowered to below 130°C. The vacuum is released and the door is opened to remove the mold.

9. The method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to claim 8, characterized in that: In step (4), a multi-layer flat plate press with six openings is used, and the above steps (1)-(4) are repeated until all openings of the multi-layer flat plate press are filled.

10. The method for preparing the continuous fiber reinforced modified polyphenylene ether thermoplastic composite foam sandwich structure board according to claim 8, characterized in that: In step (4), the vacuum is released and the door is opened to release the mold, and the lower steel plate, product and upper steel plate combination 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 opening layers of the multi-layer cold press is consistent with the number of multi-layer flat plate presses.

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