Thermoplastic lightweight continuous fiber composite material and preparation method and application thereof

Abstract

This invention provides a thermoplastic lightweight continuous fiber composite material, its preparation method, and its application. The preparation method includes: preparing layers cut to the required size and stacking them sequentially; obtaining the thermoplastic lightweight continuous fiber composite material through pressurization, temperature control, and machining. On one hand, the outer surface of the composite material is a woven or unidirectional PBO fiber layer. The molded product is sprayed with a transparent varnish to retain the golden color and fiber texture of the PBO fibers. On the other hand, the intermediate foam layer can reduce the amount of continuous fiber used, thereby reducing costs and weight. Moreover, the unidirectional or woven carbon fiber / glass fiber impregnated with thermoplastic resin is combined with PBO fibers. Based on the required characteristics and the designed thickness and strength, the type and quantity of the carbon fiber layer and / or glass fiber layer impregnated with thermoplastic resin on both sides of the intermediate foam layer are determined to maximize the strength of the board.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic sheet technology, specifically to a thermoplastic lightweight continuous fiber composite material, its preparation method, and its application. Background Technology

[0002] With the development of electronic and electrical devices and information equipment such as notebook computers, tablets, mobile phones, portable information terminals, and cameras, there is a strong market demand for thin and lightweight products. Thin and lightweight products require thin-walled, lightweight casings or internal components, as well as high strength and rigidity. Continuous fiber reinforced composite materials have advantages such as light weight, high strength and high modulus, chemical corrosion resistance, fatigue resistance, and ease of integral molding. They are widely used in the manufacture of casings for military, aircraft, automobiles, wind power, and electronic and electrical devices such as notebook computers, tablets, and portable information terminals, achieving the goals of thinner casings and lighter equipment.

[0003] Currently, most thermoplastic carbon fiber composite products used in electronics, automobiles, and sporting goods are manufactured using full carbon fiber or composite sheets made from a mixture of carbon fiber and glass fiber. The density of thermoplastic full carbon fiber composite sheets is 1.45–1.55 g / cm³. 3 The price is relatively high; the density of composite boards made from a mixture of carbon fiber and glass fiber is 1.7–1.8 g / cm³. 3 Although the price is low and the modulus and rigidity are high, the product is too heavy, which does not conform to the current trend of lightweight development.

[0004] The application of carbon fiber or glass fiber composite materials in laptops mainly involves spraying for surface treatment. The types of paint used include leather, UV, and colored paint. In particular, colored exteriors require the application of colored paint, which completely covers the fiber texture.

[0005] PBO fiber is short for poly-p-phenylene benzobisoxazole fiber. It was developed in the 1980s in the United States as a reinforcing material for composite materials to support the aerospace industry. Due to its excellent strength and heat resistance, it is widely used in military and aerospace products. Its color is golden yellow. PBO fiber has a tensile strength of 5.6 GPa, a tensile modulus of 270 GPa, and a density of 1.55 g / cm³. 3 PBO fiber has similar strength to high-strength carbon fiber T800, but its density is lower (T800 density is 1.78 g / cm³). 3 ).

[0006] In summary, there is a need to develop a thermoplastic lightweight continuous fiber composite material containing PBO fibers, as well as its preparation method and applications. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a thermoplastic lightweight continuous fiber composite material, its preparation method and application. The preparation method uses continuous unidirectional or woven PBO fibers impregnated with thermoplastic resin as the outer surface (golden yellow) of the composite board, and uses continuous unidirectional or woven carbon fiber / glass fiber impregnated with thermoplastic resin and foam material as interlayers. The mixture is mixed and hot-pressed to form a lightweight thermoplastic composite board with a golden yellow appearance. By using PBO fibers on the surface of the composite board and foam material in the middle, the golden yellow appearance and weight reduction of the composite material are achieved, while maintaining the high strength and high modulus performance of the composite board. When applied to laptop shells, the golden yellow appearance requirement can be directly achieved without the need for paint spraying, and the fiber texture will not be completely covered.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] One objective of this invention is to provide a method for preparing a thermoplastic lightweight continuous fiber composite material, the method comprising the following steps:

[0010] S1: Prepare a layer of PBO fiber impregnated with thermoplastic resin, a layer of carbon fiber impregnated with thermoplastic resin and / or a layer of glass fiber impregnated with thermoplastic resin, an intermediate foam layer, a layer of carbon fiber impregnated with thermoplastic resin and / or a layer of glass fiber impregnated with thermoplastic resin, and a layer of PBO fiber impregnated with thermoplastic resin, cut to the required size and stacked in sequence.

[0011] S2: The entire composite material obtained by lamination is pressurized and kept at a constant temperature under a set temperature, and then cooled to obtain the composite board.

[0012] S3: The cooled composite board is machined to obtain a thermoplastic lightweight continuous fiber composite material.

[0013] The preparation method of the present invention includes: preparing layers cut to the required size and stacking them sequentially, obtaining a thermoplastic lightweight continuous fiber composite material through pressurization, constant temperature, and machining. On the one hand, the outer surface of the composite material is a woven or unidirectional PBO fiber layer. After molding, the product is sprayed with transparent paint, which can retain the golden yellow color and fiber texture of the PBO fibers. On the other hand, the intermediate foaming layer can reduce the amount of continuous fiber used, thereby reducing costs and weight. Moreover, the unidirectional or woven carbon fiber / glass fiber impregnated with thermoplastic resin is combined with PBO fiber. Based on the required characteristics and the designed thickness and strength, the type and quantity of the carbon fiber layer and / or glass fiber layer impregnated with thermoplastic resin on both sides of the intermediate foaming layer are determined to maximize the strength of the board.

[0014] As a preferred technical solution of the present invention, in step S1, the thermoplastic resin includes any one or a combination of at least two of polycarbonate (PC), polyamide (PA, commonly known as nylon), polyphenylene sulfide (PPS), and polypropylene (PP).

[0015] It should be noted that, in step S1, the PBO fiber layer impregnated with thermoplastic resin is unidirectional or woven PBO fiber, and the unidirectional PBO fiber is either 0° unidirectional PBO fiber or 90° unidirectional PBO fiber. In step S1, the carbon fiber layer impregnated with thermoplastic resin is unidirectional or woven carbon fiber, and the unidirectional carbon fiber is either 0° unidirectional carbon fiber or 90° unidirectional carbon fiber. In step S1, the glass fiber layer impregnated with thermoplastic resin is unidirectional or woven glass fiber, and the unidirectional glass fiber is either 0° unidirectional glass fiber or 90° unidirectional glass fiber.

[0016] It should be noted that if two adjacent fiber layers are both unidirectional fibers, the unidirectional angles of the two adjacent layers need to be perpendicular to each other to ensure that the strength in both the transverse and longitudinal directions is maintained.

[0017] As a preferred technical solution of the present invention, in step S1, the material of the intermediate foaming layer includes any one or a combination of at least two of polypropylene (PP), polyethylene terephthalate (PET), and polyimide (PI).

[0018] As a preferred embodiment of the present invention, in step S1, the pore diameter of the intermediate foaming layer is 3–300 μm, for example, 3 μm, 10 μm, 30 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, or 300 μm. It should be noted that the pore diameter of the intermediate foaming layer is selected according to the design density and strength of the board material.

[0019] As a preferred technical solution of the present invention, in step S1, the intermediate foaming layer is bonded to the adjacent fiber layers on both sides by an adhesive, such as an tackifying acrylic adhesive, which can withstand 200-250°C in the short term and 100-120°C in the long term.

[0020] As a preferred embodiment of the present invention, in step S2, the target temperature for the pressure-controlled temperature regulation is 180–260°C, such as 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or 260°C. It should be noted that the pressure-controlled temperature regulation operation is performed in a mold, where the mold is pressurized and controlled at a set temperature. The set temperature of the mold depends on the properties of the thermoplastic resin used. For example, when PBO fibers are impregnated with PC resin, the mold temperature is 200–260°C.

[0021] As a preferred technical solution of the present invention, in step S2, the pressure and temperature holding time is 2 to 5 minutes, such as 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes.

[0022] As a preferred technical solution of the present invention, in step S2, the target cooling temperature is 50-60°C, such as 50°C, 51°C, 53°C, 55°C, 57°C, 58°C or 60°C.

[0023] As a preferred technical solution of the present invention, in step S3, the machining includes punching and / or CNC machining.

[0024] A second objective of this invention is to provide a thermoplastic lightweight continuous fiber composite material, which is prepared using the preparation method described in the first objective.

[0025] A third objective of this invention is to provide an application of a thermoplastic lightweight continuous fiber composite material, which is used in the casing of a laptop computer, comprising the following steps:

[0026] A thermoplastic lightweight continuous fiber composite material is prepared using the preparation method described in one of the objectives. Based on the target size of the laptop shell, the composite material is sequentially subjected to hot pressing, injection molding, and cooling to obtain the molded product.

[0027] Preferably, the preheating temperature of the hot-pressed plastic is 100-150°C, such as 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, and the preheating time is 20-40s, such as 20s, 25s, 30s, 35s or 40s.

[0028] Preferably, the injection molding process uses infrared radiation technology for preheating, and the preheating temperature is controlled at 100-150℃, such as 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃.

[0029] It should be noted that the composite board obtained by pressurization and constant temperature is first punched or CNC machined according to the size drawings of the laptop shell, and then hot-pressed to form the curvature required for the laptop shell. Local areas can be thinned, and then it is placed in an injection mold to injection mold the shape and structure of the laptop shell. In particular, by using PBO fibers on the surface of the composite board and foaming materials in the middle, the composite material achieves a golden appearance, lightweight and weight reduction, while maintaining the high strength and high modulus performance of the composite board.

[0030] From the fiber layer impregnated with thermoplastic resin and the intermediate foam layer to the composite material used in laptop shells, the process includes: material preparation and layering → hot pressing mold heating → layer placement and positioning in the mold → mold closing, pressure and heat preservation → mold cooling → removal of the sheet material after cooling → CNC machining according to the dimensions of the laptop shell → sheet material preheating and hot pressing → placement into the injection molding machine mold by a robotic arm, mold heating → injection molding machine mold closing, plastic injection molding structure → mold cooling → product removal.

[0031] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0032] This invention provides a thermoplastic lightweight continuous fiber composite material, its preparation method, and its application. The preparation method includes: preparing layers cut to the required size and stacking them sequentially; obtaining the thermoplastic lightweight continuous fiber composite material through pressurization, temperature control, and machining. On one hand, the outer surface of the composite material is a woven or unidirectional PBO fiber layer. The molded product is sprayed with a transparent varnish to retain the golden color and fiber texture of the PBO fibers. On the other hand, the intermediate foam layer can reduce the amount of continuous fiber used, thereby reducing costs and weight. Moreover, the unidirectional or woven carbon fiber / glass fiber impregnated with thermoplastic resin is combined with PBO fibers. Based on the required characteristics and the designed thickness and strength, the type and quantity of the carbon fiber layer and / or glass fiber layer impregnated with thermoplastic resin on both sides of the intermediate foam layer are determined to maximize the strength of the board. Attached Figure Description

[0033] Figure 1 This is an exploded view of the structure of the thermoplastic lightweight continuous fiber composite material obtained in Example 1 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0036] Example 1

[0037] This embodiment provides a method for preparing a thermoplastic lightweight continuous fiber composite material, with the goal of producing a lightweight composite carbon fiber board with a 1.45mm thick golden PBO fiber appearance. The preparation method includes the following steps:

[0038] S1: Prepare a PC resin impregnated unidirectional textured PBO fiber layer (0.1mm thick), a PC resin impregnated unidirectional textured carbon fiber layer (0.1mm thick), and a PET intermediate foam layer (1mm thick), and cut them into 1m×1m dimensions; wherein, the pore diameter of the intermediate foam layer is 30μm.

[0039] like Figure 1 As shown, the layers are stacked in the following order: a PC resin-impregnated unidirectional PBO fiber layer (0°), a PC resin-impregnated unidirectional carbon fiber layer (90°), a PC resin-impregnated unidirectional carbon fiber layer (0°), adhesive (tackifying acrylic adhesive), a PET intermediate foam layer, adhesive (tackifying acrylic adhesive), a PC resin-impregnated unidirectional carbon fiber layer (0°), a PC resin-impregnated unidirectional carbon fiber layer (90°), and a PC resin-impregnated unidirectional PBO fiber layer (0°); wherein, Figure 1 The adhesive is not shown in the image.

[0040] S2: Place the laminated whole into the hot press mold of the hot press machine. The hot press mold is pressurized and kept at 220℃ for 3 minutes. After cooling, the composite board is obtained.

[0041] S3: The cooled composite material is CNC machined according to the dimensions of the laptop shell to obtain a thermoplastic lightweight continuous fiber composite material.

[0042] This embodiment also provides an application of a thermoplastic lightweight continuous fiber composite material, which is applied to a laptop computer casing, including the following steps:

[0043] The thermoplastic lightweight continuous fiber composite material obtained in this embodiment is preheated to 120°C for 30 seconds according to the target size of the laptop shell, and then hot-pressed to form the curvature required for the laptop shell. The overlapping parts on all four sides are thinned. The hot-pressed composite sheet is then preheated using infrared radiation technology to a preheating temperature of 120°C. The preheated composite sheet is then fed into the mold of an injection molding machine and fixed. The mold is heated, the mold is closed and locked under high pressure, and the injection molding machine injects plastic to form the product structure on the composite carbon fiber sheet. After the mold cools to 60°C, the molded product is obtained.

[0044] After applying a clear coat to the molded laptop casing obtained in this embodiment, the following test results were obtained: density is 1.5 g / cm³. 3 It has a tensile strength of up to 3600MPa, a golden yellow appearance, and fully displays the fiber texture.

[0045] Example 2

[0046] This embodiment provides a method for preparing a thermoplastic lightweight continuous fiber composite material. Compared with Embodiment 1, the only difference is that the unidirectional textured carbon fiber layers (0.1 mm thick) impregnated with PC resin on both sides and adjacent to the intermediate foam layer are replaced with unidirectional textured glass fiber layers (0.1 mm thick) impregnated with PC resin. That is, the sequential stacking order in step S1 is as follows:

[0047] PC resin impregnated unidirectional textured PBO fiber layer (0°), PC resin impregnated unidirectional textured carbon fiber layer (90°), PC resin impregnated unidirectional textured glass fiber layer (0°), adhesive (tackifying acrylic adhesive), PET intermediate foam layer, adhesive (tackifying acrylic adhesive), PC resin impregnated unidirectional textured glass fiber layer (0°), PC resin impregnated unidirectional textured carbon fiber layer (90°), PC resin impregnated unidirectional textured PBO fiber layer (0°).

[0048] After applying a clear coat to the molded laptop casing obtained in this embodiment, the following test results were obtained: density is 1.5 g / cm³. 3 The tensile strength is 3500 MPa, it has a golden-yellow appearance, and fully displays the fiber texture. Compared to Example 1, the tensile strength of the laptop casing molded product obtained in this example is reduced.

[0049] Example 3

[0050] This embodiment provides a method for preparing a thermoplastic lightweight continuous fiber composite material. Compared with Example 1, the only difference is that the adhesives on both sides of the intermediate foaming layer are completely omitted.

[0051] After applying a clear coat to the molded laptop casing obtained in this embodiment, the following test results were obtained: density is 1.5 g / cm³. 3 It has a tensile strength of 3600 MPa, a golden-yellow appearance, and fully displays the fiber texture. Compared to Example 1, although the density and tensile strength of the laptop shell molded product obtained in this example are basically the same, the molded product is prone to cracking and has a reduced service life due to the omission of adhesive.

[0052] This invention mainly uses PBO fiber + UD carbon fiber and / or glass fiber + intermediate foaming layer to reduce density and ensure board strength. Moreover, PBO fiber has excellent strength and heat resistance, and its color will not change during hot pressing. After molding, the product is sprayed with transparent paint, which can retain the golden yellow color and fiber texture of PBO fiber itself. Compared with composite materials obtained by using carbon fiber and / or glass fiber, there is no need to spray colored paint on the surface, which would completely cover the original fiber texture.

[0053] This invention provides a thermoplastic lightweight continuous fiber composite material, its preparation method, and its application. The preparation method includes: preparing layers cut to the required size and stacking them sequentially; obtaining the thermoplastic lightweight continuous fiber composite material through pressurization, temperature control, and machining. On one hand, the outer surface of the composite material is a woven or unidirectional PBO fiber layer. The molded product is sprayed with a transparent varnish to retain the golden color and fiber texture of the PBO fibers. On the other hand, the intermediate foam layer can reduce the amount of continuous fiber used, thereby reducing costs and weight. Moreover, the unidirectional or woven carbon fiber / glass fiber impregnated with thermoplastic resin is combined with PBO fibers. Based on the required characteristics and the designed thickness and strength, the type and quantity of the carbon fiber layer and / or glass fiber layer impregnated with thermoplastic resin on both sides of the intermediate foam layer are determined to maximize the strength of the board.

[0054] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0055] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0056] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0057] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a thermoplastic lightweight continuous fiber composite material, characterized in that, The preparation method includes the following steps: S1: Prepare a layer of PBO fiber impregnated with thermoplastic resin, a layer of carbon fiber impregnated with thermoplastic resin and / or a layer of glass fiber impregnated with thermoplastic resin, an intermediate foam layer, a layer of carbon fiber impregnated with thermoplastic resin and / or a layer of glass fiber impregnated with thermoplastic resin, and a layer of PBO fiber impregnated with thermoplastic resin, cut to the required size and stacked in sequence. S2: The entire composite material obtained by lamination is pressurized and kept at a constant temperature under a set temperature, and then cooled to obtain the composite board. S3: The cooled composite board is machined to obtain a thermoplastic lightweight continuous fiber composite material.

2. The preparation method according to claim 1, characterized in that, In step S1, the thermoplastic resin includes any one or a combination of at least two of polycarbonate, polyamide, polyphenylene sulfide, and polypropylene.

3. The preparation method according to claim 1, characterized in that, In step S1, the material of the intermediate foam layer includes any one or a combination of at least two of polypropylene, polyethylene terephthalate, and polyimide.

4. The preparation method according to claim 1 or 3, characterized in that, In step S1, the pore diameter of the intermediate foaming layer is 3 to 300 μm.

5. The preparation method according to claim 1 or 3, characterized in that, In step S1, the intermediate foam layer is bonded to the adjacent fiber layers on both sides by an adhesive.

6. The preparation method according to claim 1, characterized in that, In step S2, the target temperature for the pressurized constant temperature is 180–260°C.

7. The preparation method according to claim 1, characterized in that, In step S2, the pressure and temperature holding time is 2 to 5 minutes.

8. The preparation method according to claim 1, characterized in that, In step S3, the machining includes punching and / or CNC machining.

9. A thermoplastic lightweight continuous fiber composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. An application of a thermoplastic lightweight continuous fiber composite material, characterized in that, Applying thermoplastic lightweight continuous fiber composite materials to laptop casings includes the following steps: A thermoplastic lightweight continuous fiber composite material is prepared using the preparation method described in any one of claims 1 to 8. Based on the target size of the laptop shell, the composite material is sequentially subjected to hot pressing, injection molding, and cooling to obtain the molded product.

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