Continuous forming method of fiber reinforced composite material profile

Abstract

The invention generally relates to the technical field of fiber reinforced composite material profile processing, in particular to a continuous forming method of a fiber reinforced composite material profile. The method comprises the following steps: 1) obtaining prepregs of a plurality of fiber materials treated by thermoplastic resin, stacking and filling the prepregs into a first mold, closing the mold at a first temperature to obtain a pressing plate, and cooling and demolding; (2) the pressing plate is fixed through a fixing piece, and the pressing plate is pre-bent into a first profile in a second mold at a second temperature; and (3) the fixing piece and the first profile are transferred into a third mold, mold closing is conducted at the third temperature, and a second profile is obtained.

Description

Technical Field

[0001] The present disclosure generally relates to the technical field of fiber reinforced composite material profile processing, and in particular, to a continuous molding method of a fiber reinforced composite material profile. Background Art

[0002] Fiber-reinforced composite prepregs are widely used in many fields such as fishing tackle, sports equipment, sports goods, aerospace and transportation. Especially in the context of the increasing demand for lightweighting in the aviation industry, its application scope is constantly expanding. Fiber-reinforced composite prepregs are intermediate materials formed by impregnating fibers with resin. They are environmentally friendly, have stable resin content, high surface quality and simple process. Prepregs can be formed into composite products through autoclave, vacuum-assisted or compression molding processes, among which the production efficiency of prepreg compression molding process is particularly outstanding.

[0003] The prepreg compression molding process includes placing the cut prepreg in the mold cavity according to the layer design for pre-molding, and then transferring it to a hot press, curing and molding it under a certain temperature and pressure, and taking out the finished product after cooling to a low temperature. Compared with other molding processes, the prepreg compression molding process has the advantages of high production efficiency, precise product size, smooth surface, good repeatability of appearance size, low production cost, and easy mechanization and automation. However, the existing prepreg compression molding process requires the prepreg to be made into a preform before compression molding. The coating of the release agent and the cleaning of the mold are time-consuming and laborious, and have an impact on the environment. Each molding cycle requires the mold to be fully cooled before demolding, resulting in a single molding cycle that is usually not less than 1 hour, which limits the application of fiber-reinforced composite materials in the aerospace field.

[0004] Chinese patent CN107187078B (a rapid compression molding process for carbon fiber prepreg) proposes to use a self-cleaning non-stick mold, coat the mold cavity with a non-stick coating, and no mold release agent is required during compression molding. There is no residue when the product is demolded, and no additional mold cleaning process is required, which reduces the mold cleaning process, saves time, and shortens the molding cycle. The shortest can be controlled within 5 minutes, and the molded product quality is good. However, this method relies on the non-stick coating, and the effect of the non-stick coating is related to the specific temperature of the process. The applicable temperature is only 80-200℃. If the process temperature is too high, it still cannot be demolded smoothly, and the versatility is poor. Summary of the invention

[0005] The present disclosure relates to a continuous molding method of a fiber-reinforced composite material profile, comprising:

[0006] 1) obtaining a plurality of prepregs of fiber materials treated with thermoplastic resin, stacking and filling them in a first mold, closing the mold at a first temperature to obtain a pressing plate, and demoulding by cooling;

[0007] 2) fixing the pressing plate by a fixing member and pre-bending it into a first profile in a second mold at a second temperature;

[0008] 3) transferring the fixing member together with the first profile into a third mold, and closing the mold at a third temperature to obtain a second profile;

[0009] in:

[0010] The first temperature is the temperature at which the resin is completely melted and easy to flow; the second temperature is approximately the melting temperature of the resin; the third temperature is higher than the glass transition stable temperature of the resin and lower than the melting temperature of the resin;

[0011] The fixing member has two lining plates arranged opposite to each other and the pressing plate / the first profile is fixed by pressing the lining plates. The lining plates are made of rigid, heat-conductive, high-temperature-resistant material, and the surface in contact with the pressing plate / the first profile is smooth.

[0012] The molding of fiber-reinforced composite material profiles usually requires a multi-step hot pressing and molding process (such as shown in the comparative example). The profiles are molded in the same mold, and the press machine is heated up + molded + cooled down during molding. The problems with this molding method are: the profile is not easy to demold at high temperatures, and the mold temperature must be lowered to room temperature before demolding. The molding time is long, up to 6h-7h, the molding efficiency is low, and the hot press needs to be repeatedly heated and cooled, which results in low molding efficiency and high energy consumption.

[0013] The present invention adopts a fixing part to fix the material and modularizes the material, so as to facilitate the transfer of the pressure plate / the first profile (which can be referred to as "material" later), and can be demolded immediately when the molding is completed, which greatly shortens the time required for cooling / heating / demolding. In addition, the surface of the fixing part in contact with the material is smooth, while the contact surface between the mold and the material is generally rough, which makes the force on the material more uniform, the surface smoother, and the performance better. Furthermore, the lining plate of the fixing part itself has a certain thickness. As needed, the space between the mold and the material can be filled, so that the mold can be suitable for a variety of materials of different thicknesses, reducing the number of molds and saving costs. Finally, the lining plate is a rigid thermally conductive material, which does not have resin and can be separated from the mold without a cooling process, so there is no problem of difficulty in demolding. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 Schematic diagram of the process disclosed in the present invention.

[0016] Figure 2 Comparison of the appearance of the profiles prepared in Comparative Example (A) and Example 5 (B).

[0017] Figure 3 Comparison of the appearance of the profiles prepared in Comparative Example (A) and Example 5 (B). DETAILED DESCRIPTION

[0018] References to embodiments of the present disclosure will now be provided in detail, one or more examples of which are described below. Each example is provided as an explanation rather than a limitation of the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the scope or spirit of the present disclosure. For example, a feature illustrated or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0019] Unless otherwise indicated, the meaning of all terms (including technical and scientific terms) used to disclose the present disclosure is the same as that commonly understood by those of ordinary skill in the art to which the present disclosure belongs. By way of further guidance, the following definitions are used to better understand the teachings of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0020] The terms "and / or", "or / and", and "and / or" used herein have a selection range that includes any one of two or more related listed items, and also includes any and all combinations of related listed items, wherein the any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in the present disclosure, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0021] As used in this disclosure, the terms "comprising," "including," and "including" are synonymous and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

[0022]

[0013] Numerical ranges recited in this disclosure as endpoints include all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0023] As used herein, reference to "about" a value or parameter includes (and describes) embodiments for the value or parameter itself. For example, a description referring to "about X" includes a description of "X". "About the melting temperature of the resin" can be understood as the melting temperature ±5°C, or ±4°C, or ±3°C, or ±2°C, or ±1°C.

[0024] The disclosure relates to length values ​​(especially non-range values), and its meaning includes fluctuations within a certain range. For example, it can fluctuate within a corresponding precision range. For example, 2%, it can allow fluctuations within ±0.1%. For values ​​with larger values ​​or values ​​that do not require too fine control, it is also allowed to include greater fluctuations. Involving time / temperature, etc., it is allowed to include fluctuations of ±10%.

[0025] As used herein, the singular articles "a," "an," and "the" include plural referents unless otherwise indicated.

[0026] In the present disclosure, descriptions such as "plurality" and "multiple" refer to quantities greater than or equal to 2 unless otherwise specified.

[0027] In the present disclosure, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0028] In the present disclosure, "preferred", "better", "more preferred", and "suitable" are only used to describe implementation methods or examples with better effects, and it should be understood that they do not constitute a limitation on the scope of protection of the present disclosure. In the present disclosure, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0029] In this article, the "first", "second", and "third" in "first mold", "second mold", "third mold", "first temperature", "second temperature", and "third temperature" are only used for descriptive purposes to distinguish between the same (or similar) things or features, and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0030] All documents mentioned in the present disclosure are cited as references in the present disclosure, just as each document is cited as a reference individually. Unless they conflict with the invention objectives and / or technical solutions of the present disclosure, the cited documents involved in the present disclosure are cited with all their contents and all their purposes. When the present disclosure involves cited documents, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the present disclosure involves cited documents, the examples and preferred methods of the cited relevant technical features may also be incorporated into the present disclosure as references, but are limited to the implementation of the present disclosure. It should be understood that when the cited content conflicts with the description in the present disclosure, the present disclosure shall prevail or be modified adaptively according to the description of the present disclosure.

[0031] The present disclosure relates to a continuous molding method of a fiber-reinforced composite material profile, comprising:

[0032] 1) obtaining a plurality of prepregs of fiber materials treated with thermoplastic resin, stacking and filling them in a first mold, closing the mold at a first temperature to obtain a pressing plate, and demoulding by cooling;

[0033] 2) fixing the pressing plate by a fixing member and pre-bending it into a first profile in a second mold at a second temperature;

[0034] 3) transferring the fixing member together with the first profile into a third mold, and closing the mold at a third temperature to obtain a second profile;

[0035] in:

[0036] The first temperature is the temperature at which the resin is completely melted and easy to flow; the second temperature is approximately the melting temperature of the resin; the third temperature is higher than the glass transition stable temperature of the resin and lower than the melting temperature of the resin;

[0037] The fixing member has two lining plates arranged opposite to each other and the pressing plate / the first profile is fixed by pressing the lining plates. The lining plates are made of rigid, heat-conductive, high-temperature-resistant material, and the surface in contact with the pressing plate / the first profile is smooth.

[0038] The first temperature can be roughly understood as a temperature 40°C to 100°C higher than the melting temperature (e.g., 50°C, 60°C, 70°C, 80°C, 90°C higher than the melting temperature). "Easy to flow" can be roughly understood as a melt index ≥ 60 g / 10 min, such as 60 g / 10 min to 100 g / 10 min, preferably 80 g / 10 min.

[0039] The third temperature can be roughly understood as a temperature that is higher than the glass transition stable temperature of the resin and 40°C to 100°C lower than the melting temperature (eg, 50°C, 60°C, 70°C, 80°C, 90°C higher than the melting temperature).

[0040] The number of layers filled with prepreg can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 29, 30, 35, 40 or more layers.

[0041] In some embodiments, the ranges of the first temperature, the second temperature, and the third temperature are all greater than 200°C.

[0042] In some embodiments, the demoulding by cooling is performed by natural cooling.

[0043] In some embodiments, the temperature of the demoulding is reduced to 20°C to 40°C, such as 25°C, 30°C, or 35°C.

[0044] The shape of the liner of the present disclosure is not particularly limited, and can be a rectangle (such as a square), a trapezoid, a parallelogram, a circle, an ellipse or an irregular shape. The shape and size of the upper and lower liner plates are usually the same. The liner plate is a flat plate.

[0045] In some embodiments, the backing plate is a metal backing plate.

[0046] In some embodiments, the material of the lining plate is one or more of silver, copper, brass, gold, aluminum, platinum, tungsten, sodium, molybdenum, titanium, nickel, iron, stainless steel, or alloys thereof. When "multiple" is selected, it means that the material of the lining plate contains multiple materials at the same time but they are not in the form of alloys.

[0047] In some embodiments, the roughness of the surface of the lining plate in contact with the pressing plate / the first profile is ≤0.5Ra, such as 0.4Ra, 0.3Ra, 0.2Ra, 0.1Ra. Preferably, both surfaces of the lining plate are smooth, and more preferably, the roughness of both surfaces is ≤0.5Ra.

[0048] In some embodiments, the thickness of the liner is 0.1 mm to 4 mm, such as 0.3 mm, 0.5 mm, 0.7 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm. By adjusting the thickness of the liner, profiles of different thicknesses can be molded with a mold of the same mold cavity thickness, thereby significantly reducing costs.

[0049] In some embodiments, the upper and lower lining boards are 10 mm to 20 mm larger than the laminate board in both length and width directions; for example, 12 mm, 14 mm, 15 mm, 16 mm, 18 mm.

[0050] In some preferred embodiments, the thickness of the lining plate is adjustable. For example, multiple layers of plate materials can be used in an overlapping manner, and one or more layers of plate materials can be removed according to the depth of the mold to adjust the thickness of the lining plate.

[0051] In some embodiments, a connector is provided between the two lining plates. The connector is preferably a rigid rod. In a preferred embodiment, the lining plate is rectangular, and the connector comprises at least four rods and is respectively installed at the four corners of the lining plate.

[0052] Preferably, the length of the connecting member is adjustable, for example, it is a telescopic sleeve.

[0053] In this specification, "fibrous material" refers to an aggregate of fibers. Before it is pre-impregnated and formed, it takes the form of strands. After forming and impregnation (particularly impregnated to the core), it has the form of a band, strip or layer. When the reinforcing fibers are continuous, their aggregates may constitute a fabric or a nonwoven fabric (NCF). When the fibers are short, their aggregates may constitute a felt or a fiber mat. In some embodiments, the fibrous material includes one or more of fibers, organic fibers or plant fibers; preferably mineral fibers include one or more of carbon fibers, glass fibers, basalt fibers, silicon oxide fibers and silicon carbide fibers; preferably organic fibers include fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers; plant fibers include natural flax fibers, hemp fibers, lignin fibers, bamboo fibers, silk fibers, especially spider silk fibers, sisal fibers, and other cellulose fibers, particularly viscose fibers. In order to promote adhesion and impregnation of thermoplastic polymer matrices, these plant fibers can be used in pure, treated, or coated forms.

[0054] The fibrous material may also be a woven, woven, or knitted fabric with fibers. It may also correspond to fibers with a supporting thread.

[0055] These constituent fibers may be used alone or in the form of a mixture. Thus, organic fibers may be mixed with mineral fibers to be pre-impregnated with the thermoplastic polymer powder and to form a pre-impregnated fibrous material.

[0056] The organic fiber strands may have several gram weights. They may further have several geometric shapes. The fibers may be in the form of short fibers, which then constitute a felt or nonwoven in the form of strips, layers or blocks, or in the form of continuous fibers, which constitute 2D textiles, braids or unidirectional (UD) strands or nonwoven fibers. The constituent fibers of the fibrous material may further take the form of a mixture of these reinforcing fibers having different geometric shapes. Preferably, the fibers are continuous.

[0057] Preferably, the fibrous material consists of continuous carbon fibers, glass fibers or silicon carbide fibers or mixtures thereof, in particular carbon fibers. It is used in the form of strands or several strands.

[0058] In some embodiments, the thermoplastic resin is selected from: polyaryletherketone (PAEK); polyaryletherketoneketone (PAEKK); aromatic polyetherimide (PEI); polyarylsulfone; polyarylsulfide; polyamide (PA); PEBA, polyacrylate; polyolefins, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers; and mixtures thereof.

[0059] For the fluorinated polymer, a homopolymer of vinylidene fluoride (VDF with the formula CH2=CF2) or a copolymer of VDF can be used, the copolymer comprising at least 50% by weight of VDF and at least one other monomer copolymerizable with VDF. The level of VDF must exceed 80% by weight, even better 90% by weight, in order to provide good mechanical strength to the structural component, especially when it is subjected to thermal and chemical stresses. The comonomer must be a fluorinated monomer, such as vinyl fluoride.

[0060] For structural parts that must withstand high temperatures, in addition to fluorinated polymers, PAEK (polyaryletherketone) such as poly(etherketone) PEK, poly(etheretherketone) PEEK, poly(etherketoneketone) PEKK, poly(etherketoneetherketoneketone) PEKEKK or PA with a high glass transition temperature Tg is advantageously used according to the present disclosure.

[0061] Advantageously, the thermoplastic polymer is a polymer whose glass transition temperature Tg≥80°C, or a semi-crystalline polymer whose melting temperature Tm≥150°C.

[0062] The embodiments of the present disclosure will be described in detail below in conjunction with examples. It should be understood that these examples are only used to illustrate the present disclosure and are not intended to limit the scope of the present disclosure. The experimental methods for which specific conditions are not specified in the following examples are preferably referred to the guidance given in the present disclosure, and can also be based on the experimental manuals or conventional conditions in the art, and can also be based on other experimental methods known in the art, or according to the conditions recommended by the manufacturer.

[0063] In the following specific embodiments, the measured parameters of raw material components may have slight deviations within the range of weighing accuracy unless otherwise specified. For temperature and time parameters, acceptable deviations caused by instrument test accuracy or operation accuracy are allowed.

[0064] In the following examples, the fiber material used is carbon fiber, which has a tensile strength of 4.9 GPa, an elastic modulus of 240 GPa, and a fiber density of 1.8 g / cm 3 ; The hot-soluble resin is polyetheretherketone resin, which has a particle size of 10 to 30 μm, a glass transition temperature of 140 to 145°C, and a melting point of 315 to 325°C.

[0065] Example 1

[0066] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0067] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0068] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0069] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0070] 5. Use anhydrous ethanol to clean mold 2 and mold 3 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of mold 2 and mold 3. The release agent is a high-temperature water-based release agent;

[0071] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold one, where the length and width of the upper and lower liner are 10-20mm larger than the laminate. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold two (mold one, mold two and mold three are installed on hot press one, hot press two and hot press three respectively, where hot press one and mold one are for pressing laminates, and hot press two, hot press three and mold two and mold three are for pressing profiles);

[0072] 7. Set the temperature of the second hot press machine to 320°C and the molding pressure to 1 MPa, and mold in the second mold cavity for 10 minutes to pre-bend the laminate into a profile with a thickness of 4 mm;

[0073] 8. Transfer the 4mm profile molded in mold 2 together with the upper and lower lining plates into the mold cavity of mold 3;

[0074] 9. The temperature of the mold cavity of mold three is maintained at 250°C and the molding pressure is maintained at 4MPa. The profile with a thickness of 4mm molded in mold two is continued to be pressurized at low temperature for 10 minutes, and the mold is opened to take out the profile and liner.

[0075] Regarding the setting of the above temperature: the melting point of the resin is 320℃. If you want to process it into a profile, you must first make the resin on the flat plate in a completely molten state (395℃) so that it can be bent and shaped; 320℃ is pre-forming near the melting point of the resin. The choice of temperature is based on the melting point of the resin, which mainly plays a pre-bending role. However, if there is no shaping molding below the melting point of the resin, the profile is taken out directly, and the resin still has a certain fluidity. The profile will shrink and produce defects, so it is necessary to press it again below the melting point (250℃) to compact the profile.

[0076] Example 2

[0077] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0078] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0079] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0080] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0081] 5. Use anhydrous ethanol to clean mold 2 and mold 3 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of mold 2 and mold 3. The release agent is a high-temperature water-based release agent;

[0082] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold one, where the length and width of the upper and lower liner are 10-20mm larger than the laminate. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold two (mold one, mold two and mold three are installed on hot press one, hot press two and hot press three respectively, where hot press one and mold one are for pressing laminates, and hot press two, hot press three and mold two and mold three are for pressing profiles);

[0083] 7. Set the temperature of the second hot press machine to 340°C and the molding pressure to 1 MPa, and pre-bend the laminate into a profile with a thickness of 4 mm in the mold cavity of the second mold for 10 minutes;

[0084] 8. Transfer the 4mm profile molded in mold 2 together with the upper and lower lining plates into the mold cavity of mold 3;

[0085] 9. The temperature of the mold cavity of mold three is maintained at 270°C and the molding pressure is maintained at 4MPa. The profile with a thickness of 4mm molded in mold two is continued to be pressurized at low temperature for 10 minutes, and the mold is opened to take out the profile and liner.

[0086] Example 3

[0087] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0088] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0089] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0090] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0091] 5. Use anhydrous ethanol to clean mold 2 and mold 3 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of mold 2 and mold 3. The release agent is a high-temperature water-based release agent;

[0092] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold one, where the length and width of the upper and lower liner are 10-20mm larger than the laminate. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold two (mold one, mold two and mold three are installed on hot press one, hot press two and hot press three respectively, where hot press one and mold one are for pressing laminates, and hot press two, hot press three and mold two and mold three are for pressing profiles);

[0093] 7. Set the temperature of the second hot press machine to 300°C and the molding pressure to 1 MPa, and pre-bend the laminate into a profile with a thickness of 4 mm in the mold cavity of the second mold for 10 minutes;

[0094] 8. Transfer the 4mm profile molded in mold 2 together with the upper and lower lining plates into the mold cavity of mold 3;

[0095] 9. The temperature of mold cavity three is maintained at 230℃ and the molding pressure is maintained at 4MPa. The profile with a thickness of 4mm molded in mold two is continued to be pressurized at low temperature (equivalent to the temperature mentioned above, 250℃ is considered low) for 10 minutes, and the mold is opened to take out the profile and liner.

[0096] Example 4

[0097] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0098] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0099] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0100] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0101] 5. Use anhydrous ethanol to clean mold 2 and mold 3 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of mold 2 and mold 3. The release agent is a high-temperature water-based release agent;

[0102] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold one, where the length and width of the upper and lower liner are 10-20mm larger than the laminate. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold two (mold one, mold two and mold three are installed on hot press one, hot press two and hot press three respectively, where hot press one and mold one are for pressing laminates, and hot press two, hot press three and mold two and mold three are for pressing profiles);

[0103] 7. Set the temperature of the second hot press machine to 320°C and the molding pressure to 1 MPa, and mold in the second mold cavity for 5 minutes to pre-bend the laminate into a profile with a thickness of 4 mm;

[0104] 8. Transfer the 4mm profile molded in mold 2 together with the upper and lower lining plates into the mold cavity of mold 3;

[0105] 9. The temperature of mold cavity three is maintained at 250℃ and the molding pressure is maintained at 4MPa. The profile with a thickness of 4mm molded in mold two is continued to be pressurized at low temperature (equivalent to the temperature mentioned above, 250℃ is considered low) for 5 minutes, and the mold is opened to take out the profile and liner.

[0106] Example 5

[0107] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0108] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0109] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0110] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0111] 5. Use anhydrous ethanol to clean mold 2 and mold 3 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of mold 2 and mold 3. The release agent is a high-temperature water-based release agent;

[0112] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold one, where the length and width of the upper and lower liner are 10-20mm larger than the laminate. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold two (mold one, mold two and mold three are installed on hot press one, hot press two and hot press three respectively, where hot press one and mold one are for pressing laminates, and hot press two, hot press three and mold two and mold three are for pressing profiles);

[0113] 7. Set the temperature of the second hot press machine to 320°C and the molding pressure to 1 MPa, and pre-bend the laminate into a profile with a thickness of 4 mm in the mold cavity of the second mold for 3 minutes;

[0114] 8. Transfer the 4mm profile molded in mold 2 together with the upper and lower lining plates into the mold cavity of mold 3;

[0115] 9. The temperature of the mold cavity of mold three is maintained at 250°C and the molding pressure is maintained at 4MPa. The profile with a thickness of 4mm molded in mold two is continued to be pressurized at low temperature for 3 minutes, and the mold is opened to take out the profile and liner.

[0116] Comparative Example

[0117] The specific forming steps of the profile are:

[0118] 1. Clean the mold 1 with anhydrous ethanol. After cleaning, evenly apply a layer of release agent on the inner surface of the mold 1. The release agent is a high-temperature water-based release agent;

[0119] 2. The 28 layers of quasi-isotropic prepreg are laid, and the laid 28 layers of quasi-isotropic prepreg are placed in the mold cavity of a 4 mm thick mold 1 fixed on a hot press, and the mold is closed;

[0120] 3. The temperature of the mold cavity on the hot press is maintained at 395°C and the molding pressure is maintained at 3MPa, and the 28 layers of quasi-isotropic prepreg are molded into a flat laminate with a thickness of 4mm;

[0121] 4. Wait for the temperature of mold 1 to cool naturally to 30°C (the cooling speed on both sides of mold 1 remains consistent), and then demoulding is completed;

[0122] 5. Use anhydrous ethanol to clean the mold 2 with a mold cavity thickness of 4 mm, and evenly apply a layer of release agent on the inner surface of the mold cavity of the mold 2. The release agent is a high-temperature water-based release agent;

[0123] 6. Add a layer of 0.1mm liner on the upper and lower sides of the 4mm flat laminate molded in mold 1, where the upper and lower liner sizes are 10-20mm larger than the laminate size in both length and width directions. After softening on a heating table at 395°C for 5 minutes, the laminate and the liner are moved together into the mold cavity of mold 2 (mold 1 and mold 2 are installed in hot press 1 and hot press 2 respectively, where hot press 1 and mold 1 are for pressing laminates, and hot press 2 and mold 2 are for pressing profiles);

[0124] 7. Set the temperature of the second hot press machine to 320°C and the molding pressure to 1 MPa. Bend the laminate into a profile with a thickness of 4 mm in the mold cavity of the second mold for 10 minutes. Open the mold and take out the profile and liner.

[0125] The preferred embodiment (Example 5) of the present disclosure is compared with the comparative example, and the results are shown in the following table:

[0126]

[0127]

[0128] In the comparative example, each round of profile molding (corresponding to step 7 in the comparative example; corresponding to steps 7-9 in the embodiment) requires a complete press heating + molding + cooling procedure, so even under relatively ideal process conditions, molding a profile requires 2h+20min+2h=260min; in the embodiment, the press needs to be heated up only once at the beginning of the process, but from the second round onwards, each press does not need to repeat the heating and cooling process, and only needs to maintain a constant temperature. The time consumed is only the molding time of each step, which is about 5min+3min+3min=11min.

[0129] according to Figure 2 and Figure 3 As shown, by adopting the improved process disclosed in the present invention, the addition of the liner makes it easy for the profile to be demolded at high temperatures, so the high-temperature pre-pressing step and the low-temperature pressurizing step of the profile can be separated to obtain greater molding efficiency. By adopting the secondary molding method, the prepared profile has an obviously smoother and flatter surface and better strength. The prepreg of the comparative example is difficult to compact, so the profile has a high defect rate and poor strength. In addition, the profile obtained by the improved process molding has a stronger ability to bear loads. It can withstand a load of 1650N per unit cross-sectional area, while the aluminum alloy used in aerospace can only withstand a load of 898N per unit cross-sectional area, and the profile density is only 1.6g / cm 3 , the density of aluminum alloy is 2.7g / cm 3 . Both strength and quality are far superior to aluminum alloy.

[0130] The above-described embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure shall be based on the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. A continuous molding method for a fiber reinforced composite material profile, comprising: 1) obtaining a plurality of prepregs of fiber materials treated with thermoplastic resin, stacking and filling them in a first mold, closing the mold at a first temperature to obtain a pressing plate, and demoulding by cooling; 2) fixing the pressing plate by a fixing member and pre-bending it into a first profile in a second mold at a second temperature; 3) transferring the fixing member together with the first profile into a third mold, and closing the mold at a third temperature to obtain a second profile; in: The first temperature is the temperature at which the resin is completely melted and easy to flow; the second temperature is approximately the melting temperature of the resin; the third temperature is higher than the glass transition stable temperature of the resin and lower than the melting temperature of the resin; The fixing member has two lining plates arranged opposite to each other and the pressing plate / the first profile is fixed by pressing the lining plates. The lining plates are made of rigid, heat-conductive, high-temperature-resistant material, and the surface in contact with the pressing plate / the first profile is smooth.

2. The method according to claim 1, wherein the demoulding is performed by natural cooling; preferably, the temperature is lowered to 20°C to 40°C. The method according to claim 1 , wherein the liner is a metal liner.

4. According to the method of claim 3, the material of the lining plate is one or more of silver, copper, brass, gold, aluminum, platinum, tungsten, sodium, molybdenum, titanium, nickel, iron, stainless steel, or their alloys.

5. According to the method described in any one of claims 1 to 4, the roughness of the surface of the lining plate in contact with the pressing plate / the first profile is ≤0.5Ra; preferably, the roughness of both surfaces of the lining plate is ≤0.5Ra.

6. The method according to any one of claims 1 to 4, wherein the thickness of the lining plate is 0.1 mm to 4 mm.

7. The method according to any one of claims 1 to 4, wherein the thickness of the lining plate is adjustable.

8. According to the method according to any one of claims 1 to 4, a connecting piece is provided between the two lining plates, and preferably the length of the connecting piece is adjustable.

9. According to the method according to any one of claims 1 to 4, the fiber material includes one or more of mineral fibers, organic fibers or plant fibers; preferably, the mineral fibers include one or more of carbon fibers, glass fibers, basalt fibers, silicon oxide fibers and silicon carbide fibers; preferably, the organic fibers include fibers based on thermoplastic or thermosetting polymers, such as at least one of semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers; preferably, the plant fibers include at least one of natural flax fibers, hemp fibers, lignin fibers, bamboo fibers, silk fibers, especially spider silk fibers, and sisal fibers.

10. The method according to any one of claims 1 to 4, wherein the thermoplastic resin is selected from: polyaryletherketone (PAEK); polyaryletherketoneketone (PAEKK); aromatic polyetherimide (PEI); polyarylsulfone; polyarylsulfide; polyamide (PA); PEBA, polyacrylate; polyolefin, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers; and mixtures thereof.

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