A method for forming a carbon fiber thermoplastic composite material by co-solidification

Abstract

The application belongs to the field of materials and provides a physical and chemical co-solidification connecting forming method of carbon fiber thermoplastic composite material, wherein the connecting structure is combined by stacking the upper and lower surface layers and the intermediate layer through a concave structure, and a reinforcing layer is connected to form a secondary infiltration connecting whole part under certain temperature and pressure. The forming method adopts a mixed co-solidification plate forming mode combining the physical and mechanical mode and the chemical infiltration method, thereby effectively improving the strength of the connected composite material plate. In addition, the connecting part adopts a carbon fiber three-dimensional weaving structure, so that the structural rigidity, strength and stability are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of materials, and relates to a non-mechanical connecting method of a thermoplastic composite plate or profile, in particular to a connecting method of physical and chemical method mixed co-solidification forming by splicing and secondary infiltration forming of thermoplastic resin. BACKGROUND

[0002] The information disclosed in this background section is only intended to increase an understanding of the general context of the present application and does not necessarily constitute admission of prior art of any form of suggestion that this information forms part of the prior art that is already known to a person of ordinary skill in the art.

[0003] The carbon fiber thermoplastic composite material is a kind of carbon fiber multidimensional fabric reinforced composite material using thermoplastic resin as matrix. The repeated plasticizing forming heat characteristics of thermoplastic resin can be used for multiple processing forming, and can be used for rapid processing forming of plates, various special-shaped plates or multi-curved profiles. For large-sized composite material plates or profiles, material connection is inevitable. The traditional connection method is mechanical connection (screws, nuts, etc.) or adhesive connection. For carbon fiber composite materials, if mechanical connection is used, local hole drilling of the plate or profile is inevitable, which will cause stress concentration and damage problems for subsequent use of structural members. For adhesive connection, since most thermoplastic resins belong to non-polar material type, the requirements for adhesives are very strict, and the adhesive strength is often low, which is prone to interface debonding problems at the connection. SUMMARY

[0004] In order to solve the above problems, the present application provides a physical and chemical co-solidification connecting plate or profile forming method of carbon fiber thermoplastic composite material. The present application realizes the effective connection of carbon fiber thermoplastic composite material plate or profile by using physical and chemical method mixed co-solidification forming of splicing and secondary infiltration forming of thermoplastic resin.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] In a first aspect of the present application, a carbon fiber thermoplastic composite structure is provided, which adopts a three-layer laminated combination design, including: an upper surface layer, a middle layer, a lower surface layer, and a reinforcing layer; the upper surface layer is provided with a first male joint, the lower surface layer is provided with a second male joint, the upper surface of the middle layer is provided with a first female interface, and the lower surface of the middle layer is provided with a second female interface; the upper surface layer, the middle layer and the lower surface layer are arranged in sequence from top to bottom; the first male joint is embedded in the first female interface; the reinforcing layer is arranged between the first male joint and the first female interface; the second male joint is embedded in the second female interface; and the reinforcing layer is arranged between the second male joint and the second female interface.

[0007] The present application adopts the upper and lower surface layers and the intermediate layer to be laminated and combined, and then the connection reinforcing layer is used to form a secondary infiltration connection whole piece under certain temperature and pressure.

[0008] In some embodiments, the upper and lower surface layers adopt a three-dimensional woven fabric structure.

[0009] In some embodiments, the three-dimensional woven fabric structure of the upper and lower surfaces adopts any one of three-dimensional four-way, three-dimensional five-way, three-dimensional six-way, and three-dimensional seven-way fabric structures, and the three-dimensional fabric structures of the upper and lower surface layers can be designed in any combination.

[0010] In some embodiments, the intermediate layer adopts a planar fabric structure.

[0011] In some embodiments, the intermediate layer adopts any one of carbon fiber planar plain weave, twill weave, or satin weave.

[0012] The thickness of the upper surface layer, the intermediate layer, and the lower surface layer can be flexibly adjusted according to design requirements.

[0013] Further, the carbon fibers in the forming structure of the composite plate or profile can be any one of T300, T700, T800, T1000, and are not limited to the above types. The mixed fiber structure of carbon fibers and glass fibers, aramid fibers can also be used, wherein the mixing ratio can be flexibly adjusted according to design requirements.

[0014] The composite plate or profile can be formed by melting and infiltrating the above laminated layered fabric using a thermoplastic resin matrix, wherein the resin matrix can be any one of polyethylene, polypropylene, polyurethane, polyphenylene sulfide, polyamide, polyformaldehyde, terephthalic acid glycol, polyether ketone, polyether ether ketone, and is not limited to the above types. The final resin content is controlled within the range of 40-60%.

[0015] The interface connection part of the composite plate or profile adopts a concave reserved interface design, and the length of the upper and lower surface layers on both sides is greater than that of the intermediate layer, forming a concave structure along the thickness section of the plate, and the depth can be flexibly designed according to the connection design requirements.

[0016] The forming of the composite plate or profile can be performed by hot pressing, first hot pressing and infiltrating each single layer of the three-layer structure, then laminating and secondarily infiltrating the three layers, the single layer infiltration and secondary infiltration temperature can be flexibly designed according to the type of thermoplastic resin, the heating temperature range is flexibly adjusted within the range of 1-15 MPa during the heating process, and the single layer and secondary infiltration time is flexibly adjusted within the range of 30-90 min.

[0017] In some embodiments, the reinforcing layer adopts a hybrid carbon fiber multidimensional structure fabric.

[0018] In some embodiments, the hybrid carbon fiber multidimensional structure fabric of the reinforcing layer adopts high modulus carbon fiber hybrid high strength carbon fiber to form, adopting any one of three-dimensional four-way, three-dimensional five-way, three-dimensional six-way, three-dimensional seven-way, etc.

[0019] Further, the high modulus carbon fiber can be selected from any one of M40, M40J, M55, M55J, M60, M60J, etc., the high strength carbon fiber can be selected from any one of T300, T700, T800, T1000, etc., and is not limited to the above types, and the hybrid ratio of the two fibers can be adjusted according to design requirements.

[0020] The thickness of the multidimensional structure fabric connecting the reinforcing layer fiber preform and the thickness of the final connecting reinforcing layer are flexibly designed according to the connecting concave depth and thickness.

[0021] In a second aspect of the present application, a physical and chemical co-solidification forming method of carbon fiber thermoplastic composite material is provided, comprising:

[0022] The forming structure of the composite material plate is designed to be a multidimensional structure stack combination, and a concave interface is reserved at the connecting part;

[0023] The hybrid carbon fiber multidimensional structure fabric is used to form the connecting reinforcing layer fiber preform;

[0024] In the connecting forming process, the concave structure of the carbon fiber thermoplastic composite material to be connected is pre-assembled through the connecting reinforcing layer fiber preform, and then placed in an injection mold to inject and impregnate the connecting reinforcing layer fiber preform with high flow modified thermoplastic resin under high pressure, while synchronously performing secondary melting and impregnation high temperature heating and pressurization treatment on the interface position of the connecting profile or plate, and finally forming an overall composite material part after a certain connection processing time.

[0025] In some embodiments, in the connecting forming process, the concave structure of the carbon fiber thermoplastic composite material to be connected is pre-assembled through the connecting reinforcing layer fiber preform, the plate concave structure is docked, and the connecting reinforcing layer fiber preform is embedded in the cavity formed by the concave structure to form a pre-assembled structure, and then the assembled structure is placed in a connecting hot press heater for secondary melting and impregnation forming, and the forming temperature is flexibly adjusted according to the type of thermoplastic resin matrix. The hot press pressure is controlled within the range of 1-10 MPa.

[0026] In some embodiments, the secondary infiltration connection forming process synchronously uses a high-pressure injection tool to inject and impregnate the high-flow modified thermoplastic resin into the inside of the reinforced layer fiber preform in the connection cavity, the high-flow modified thermoplastic resin used is of the same type as the resin of the connection plate material, the injection temperature is consistent with the heating temperature range of the connection forming, the injection pressure is controlled within the range of 10-20 MPa, and the injection time is controlled within the range of 10-30 min.

[0027] In some embodiments, the processing time of the secondary infiltration connection forming is controlled within the range of 30-90 min and can be flexibly designed according to the requirements of connection forming and co-curing treatment.

[0028] Advantages of the present application

[0029] (1) The present application adopts a mixed co-curing plate forming method combining physical and mechanical methods and chemical infiltration methods, thereby improving the strength of the composite material plate connection.

[0030] (2) The present application avoids using mechanical hole opening methods, thereby avoiding the stress concentration problem of the composite material caused by hole opening. The present application adopts a splicing type design of three layers of laminates, and uses a carbon fiber three-dimensional woven structure (reinforced layer) at the interface bonding part, thereby effectively improving the interface bonding strength of the carbon fiber thermoplastic composite material plate or profile.

[0031] (3) The present application uses a carbon fiber three-dimensional woven structure at the interface bonding part, thereby effectively improving the rigidity of the connection interface and improving the interface bonding strength.

[0032] (4) The preparation method of the present application is simple, practical, and easy to popularize. DETAILED DESCRIPTION

[0033] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the exemplary embodiments of the present application and the description thereof serve to explain the present application and do not constitute an improper limitation on the present application.

[0034] Figure 1 It is a kind of carbon fiber thermoplastic composite material physicochemical co-solidification connection plate or profile forming method, 1 upper surface layer, 2 middle layer, 3 lower surface layer, 4 reinforced layer. DETAILED DESCRIPTION

[0035] It should be pointed out that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0036] Term explanation:

[0037] “M40, M40J, M55, M55J, M60, M60J” are all trade names of high modulus carbon fibers.

[0038] “T300, T700, T800, T1000” are all trade names of high strength carbon fibers.

[0039] The present application will be further described in detail below with reference to specific examples, which are intended to explain but not limit the present application.

[0040] Example 1

[0041] A method for forming a plate or profile of physical-chemical co-solidification connection of carbon fiber thermoplastic composite material, specifically, in the first step, a three-layer laminated combination design of multi-dimensional structure is performed on the forming structure of the composite material plate, and a concave interface is reserved for the connection part. The upper and lower surface layers adopt a three-dimensional four-directional fabric structure of T300 carbon fiber, and the middle layer adopts a plain weave fabric structure of T300 carbon fiber. The length of the two side surface layers exceeds the middle layer by 50 mm. Each single layer of the three-layer structure is subjected to hot-pressing infiltration (i.e., one-time infiltration), respectively forming a corresponding carbon fiber thermoplastic composite material structure.

[0042] In the second step, a three-dimensional four-directional structure fabric of 1:1 mixed M40 high modulus carbon fiber mixed T300 high strength carbon fiber is used to form a connection reinforcement layer fiber preform to strengthen the connection part, and the number of its layers is 4.

[0043] In the third step, during the connection forming process, the concave structure of the carbon fiber thermoplastic composite material to be connected is pre-laminated and assembled through the connection reinforcement layer fiber preform, and then placed in an injection mold to inject and impregnate the connection reinforcement layer fiber preform with high-flow modified thermoplastic resin under high pressure, while simultaneously performing a secondary infiltration treatment on the interface position of the connection profile or plate under a pressure of 1 MPa and a temperature of 210°C. After 30 minutes, the overall composite material part is finally formed.

[0044] Example 2

[0045] A method for forming a plate or profile of physical-chemical co-solidification connection of carbon fiber thermoplastic composite material, specifically, in the first step, a three-layer laminated combination design of multi-dimensional structure is performed on the forming structure of the composite material plate, and a concave interface is reserved for the connection part. The upper and lower surface layers adopt a three-dimensional four-directional fabric structure of T300 carbon fiber, and the middle layer adopts a plain weave fabric structure of T300 carbon fiber. The length of the two side surface layers exceeds the middle layer by 50 mm. Each single layer of the three-layer structure is subjected to hot-pressing infiltration (i.e., one-time infiltration), respectively forming a corresponding carbon fiber thermoplastic composite material structure.

[0046] Second step, the 3D seven-way multidimensional fabric of M55 high modulus carbon fiber mixed with T700 high strength carbon fiber in a ratio of 2:1 is used to form the connecting reinforcement layer fiber preform to strengthen the connecting part, and the number of layers is 5.

[0047] Third step, during the connecting forming process, the concave structure of the carbon fiber thermoplastic composite plate to be connected is pre-laminated by the connecting reinforcement layer fiber preform, and then placed in an injection mold to inject and impregnate the connecting reinforcement layer fiber preform with high flow modified thermoplastic resin under high pressure, while simultaneously performing secondary infiltration treatment on the interface position of the connecting profile or plate under a pressure of 2 MPa and a temperature of 220°C. After 40 minutes, the overall composite part is finally formed.

[0048] Example 3

[0049] A forming method of a carbon fiber thermoplastic composite material physical and chemical co-solid connection plate or profile, specifically, first step, the multidimensional three-layer laminated design is performed on the forming structure of the composite material plate, and a concave interface is reserved for the connecting part. The upper and lower surface layers adopt a 3D six-way three-dimensional fabric structure of T800 carbon fiber, and the middle layer adopts a satin plane fabric structure of T800 carbon fiber. The length of the two surface layers exceeds the middle layer by 60 mm. Each single layer of the three-layer structure is subjected to hot-pressing infiltration (i.e., primary infiltration) to form a corresponding carbon fiber thermoplastic composite structure.

[0050] Second step, the 3D six-way multidimensional fabric of M60 high modulus carbon fiber mixed with T800 high strength carbon fiber in a ratio of 3:1 is used to form the connecting reinforcement layer fiber preform to strengthen the connecting part, and the number of layers is 5.

[0051] Third step, during the connecting forming process, the concave structure of the carbon fiber thermoplastic composite plate to be connected is pre-laminated by the connecting reinforcement layer fiber preform, and then placed in an injection mold to inject and impregnate the connecting reinforcement layer fiber preform with high flow modified thermoplastic resin under high pressure, while simultaneously performing secondary infiltration treatment on the interface position of the connecting profile or plate under a pressure of 4 MPa and a temperature of 230°C. After 30-90 minutes, the overall composite part is finally formed.

[0052] Example 4

[0053] A kind of carbon fiber thermoplastic composite material's physical and chemical co-solidification connection plate or section bar forming method, specifically, first, the three-layer laminated combination design of multidimensional structure is carried out to the forming structure of composite material plate, and recessed interface is reserved for connecting part.The upper and lower surface layer adopts the three-dimensional seven-directional three-dimensional fabric structure of T1000 carbon fiber, and the middle layer adopts the satin plane fabric structure of T800 carbon fiber.The length of two side surface layers exceeds middle layer 80mm.The hot-pressing infiltration (i.e.: once infiltration) is carried out to each single layer of three-layer structure, and corresponding carbon fiber thermoplastic composite material structural member is formed respectively.

[0054] Second, the three-dimensional six-directional multidimensional structure fabric of 3.5:1 ratio mixed M60J high-modulus carbon fiber mixed T1000 high-strength carbon fiber is used to form connecting reinforcement layer fiber preform to strengthen the connecting part, and the number of its laying is 6 layers.

[0055] Third, during connecting forming processing, the recessed structure of carbon fiber thermoplastic composite material plate needing connection is pre-laminated assembly through connecting reinforcement layer fiber preform, then it is placed in injection mold, high-flow modified thermoplastic resin is high-pressure injected to impregnate connecting reinforcement layer fiber preform, and at the same time, the interface position of connecting section bar or plate is simultaneously subjected to secondary infiltration treatment of pressure 8MPa and temperature 200 DEG C, after 90min, finally, overall composite material piece is formed.

[0056] The above only for the preferred embodiment of the present application and does not limit the present application, for the person skilled in the art, the present application can have various changes and variations.Any modification, equivalent replacement, improvement, etc., within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A method of forming a carbon fiber thermoplastic composite material physical-chemical co-bonding connection, characterized by, The application relates to a carbon fiber thermoplastic composite material and a preparation method thereof. A multi-dimensional structure is designed by laminating and combining the forming structure of the composite material plate, and a concave interface is reserved at a connecting position; A connecting reinforcing layer fiber preform is formed by using a hybrid carbon fiber multi-dimensional structure fabric; During the connecting forming process, each single layer of the upper surface layer, the middle layer and the lower surface layer is firstly subjected to hot-pressing and melting penetration, the concave structure of the carbon fiber thermoplastic composite material plate to be connected is pre-assembled through the connecting reinforcing layer fiber preform, and then the connecting reinforcing layer fiber preform is placed in an injection mold to inject and impregnate the high-flow modified thermoplastic resin into the connecting reinforcing layer fiber preform under high pressure, meanwhile, the interface position of the connecting profile or plate is subjected to secondary melting penetration, high-temperature heating and pressurizing treatment, and finally, the whole composite material part is formed after a certain connecting treatment time. The carbon fiber thermoplastic composite material comprises an upper surface layer, a middle layer, a lower surface layer and a reinforcing layer, the upper surface layer is provided with a first convex joint, the lower surface layer is provided with a second convex joint, the upper surface of the middle layer is provided with a first concave interface, the lower surface of the middle layer is provided with a second concave interface, the upper surface layer, the middle layer and the lower surface layer are sequentially arranged from top to bottom, the first convex joint is embedded in the first concave interface, the reinforcing layer is arranged between the first convex joint and the first concave interface, the second convex joint is embedded in the second concave interface, and the reinforcing layer is arranged between the second convex joint and the second concave interface.

2. The carbon fiber thermoplastic composite coform process of claim 1, wherein, The hot-pressing forming method is used to firstly perform hot-pressing and melting penetration on each single layer of the upper surface layer, the middle layer and the lower surface layer, then perform laminating and secondary melting penetration combination treatment on the upper surface layer, the middle layer and the lower surface layer, the melting penetration and secondary melting penetration temperature is flexibly designed according to the heating temperature range of the thermoplastic resin type, the pressure during the heating process is controlled within the range of 1-15 MPa, and the single layer melting penetration and secondary melting penetration time is within the range of 30-90 min.

3. The carbon fiber thermoplastic composite coform process of claim 1, wherein, The high-flow modified thermoplastic resin matrix used is consistent with the resin type of the connected plate, the injection temperature is consistent with the connecting forming heating temperature range, the injection pressure is controlled within the range of 10-20 MPa, and the injection time is controlled within the range of 10-30 min. The processing time of the secondary melting penetration connecting forming is controlled within the range of 30-90 min.

4. The carbon fiber thermoplastic composite material structure prepared by the method in any one of claims 1-3.

5. The carbon fiber thermoplastic composite structure of claim 4, wherein, The upper and lower surface layers adopt a three-dimensional woven fabric structure.

6. The carbon fiber thermoplastic composite structure of claim 5, wherein, The three-dimensional woven fabric structure adopts any one of a three-dimensional four-way, a three-dimensional five-way, a three-dimensional six-way and a three-dimensional seven-way fabric structure.

7. The carbon fiber thermoplastic composite structure of claim 4, wherein, The middle layer adopts a planar fabric structure.

8. The carbon fiber thermoplastic composite structure of claim 7, wherein, The middle layer adopts any one of a carbon fiber planar plain weave, a carbon fiber planar twill weave or a carbon fiber planar satin weave.

9. The carbon fiber thermoplastic composite structure of claim 4, wherein, The hybrid carbon fiber multi-dimensional structure fabric is formed by using high-modulus carbon fibers and high-strength carbon fibers, and adopts any one of a three-dimensional four-way, a three-dimensional five-way, a three-dimensional six-way and a three-dimensional seven-way fabric structure type.

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