A method of making a thermoplastic composite article

Abstract

The application discloses a method for preparing a thermoplastic composite product, comprising: providing a fiber preform to a feeding section; transferring the fiber preform to a hot pressing section to heat the fiber preform to a first preset temperature, which is greater than or equal to a viscous flow temperature or a melting temperature of a thermoplastic resin, so as to plasticize the fiber preform, and compact the plasticized fiber preform to provide a composite product; and transferring the composite product to a cooling section to cool the composite product to a second preset temperature, which is less than or equal to a crystallization temperature or a glass transition temperature of the thermoplastic resin, so as to shape the composite product. Thus, the fiber orientation of the fiber preform is in a tangential direction perpendicular to a length direction, so that the tensile strength, compression strength and modulus of the composite product in the tangential direction are improved. The method is especially suitable for preparing a composite product in the form of a bar, a pipe or a profile with a similar structure, and the extrusion length can be adjusted according to requirements to improve production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a preparation method of a thermoplastic composite material product. BACKGROUND

[0002] The forming of the thermoplastic composite material usually adopts processing methods such as injection molding, extrusion, and mold pressing. Among them, the injection molding and the extrusion processing are prone to break the fibers, affecting the final mechanical strength of the product; and the mold pressing method has small damage to the fibers, but needs to prepare a prepreg in advance, so that the resin and the fibers are uniformly mixed in advance, such as related technologies can first prepare a unidirectional cloth, the thermoplastic resin is well infiltrated into the unidirectional fibers to form a thin layer cloth, or the fibers are impregnated with the thermoplastic resin, and then the thermoplastic resin is heated and molded to prepare a sheet, a plate and the like.

[0003] In related technologies, the unidirectional cloth impregnated with the thermoplastic resin can also be heated and wound to prepare a pipe or a rod. Or, the thermoplastic resin and the fibers are mixed as processing raw materials, melted by an extruder, and then cooled and shaped through a certain shaped die, and then cut to a fixed length, but such processing will cut the fibers into short fibers (length <1mm), and the fibers are randomly oriented or preferentially oriented along the extrusion direction.

[0004] However, the strength of the composite material product is closely related to the fiber orientation, and generally has higher tensile strength, compressive strength and modulus along the fiber direction. In some special occasions, it is required that the profile has high compression resistance and tensile resistance along the cross direction, but it is difficult to achieve by using the forming method in the related technologies. SUMMARY

[0005] The embodiment of the present application discloses a preparation method of a thermoplastic composite material product, which can solve the problem of low tensile strength, compressive strength and modulus of the composite material product in the cross direction in related technologies.

[0006] In order to achieve the above purpose, a preparation method of a thermoplastic composite material product, the composite material product is formed in a mold cavity of an extrusion die, the extrusion die includes a feeding section, a hot pressing section and a cooling section arranged in the mold cavity in sequence along the feeding direction of the mold cavity, and the method comprises the following steps:

[0007] The fiber pre-product is provided to the feeding section.

[0008] The fiber pre-product is transported to the hot pressing section.

[0009] The fiber pre-product is heated to be greater than or equal to a first preset temperature in the hot pressing section, so as to plasticize the fiber pre-product, and the plasticized fiber pre-product is compacted to provide the composite material product.

[0010] The composite material product is transported to the cooling section.

[0011] cooling the composite article to a second preset temperature or less in a cooling section to shape the composite article.

[0012] wherein the second preset temperature is less than the first preset temperature; the fiber preform comprises a plurality of fiber preform pieces stacked along a length direction, the fiber preform piece is one of a multi-directional fiber preform piece and a unidirectional fiber preform piece; wherein the multi-directional fiber preform piece comprises at least two kinds of fibers with intersecting fiber orientations and a thermoplastic resin; the unidirectional fiber preform piece comprises one kind of fiber with consistent fiber orientation and a thermoplastic resin; the fiber preform comprises at least two kinds of unidirectional fiber preform pieces with intersecting fiber orientations, or the fiber preform comprises a multi-directional fiber preform piece; the length direction is consistent with the feeding direction, the fiber orientation is perpendicular to the length direction; the compaction direction is parallel to the length direction.

[0013] Optionally, the first preset temperature is a viscous flow temperature or a melting temperature of the thermoplastic resin.

[0014] Optionally, the second preset temperature is a crystallization temperature or a glass transition temperature of the thermoplastic resin.

[0015] Optionally, before the fiber preform is provided to the feeding section, the method further comprises:

[0016] pre-impregnating the fiber cloth in the thermoplastic resin to provide the fiber preform piece; the fiber cloth is a multi-directional fiber cloth or a unidirectional fiber cloth; the multi-directional fiber cloth comprises at least two kinds of reinforcing fibers with intersecting fiber orientations, and the unidirectional fiber cloth has consistent fiber orientation of the reinforcing fibers inside.

[0017] stacking the fiber preform pieces along the length direction to provide the fiber preform.

[0018] In some other optional embodiments, before the fiber preform is provided to the feeding section, the method further comprises:

[0019] providing auxiliary fiber filaments and main fiber filaments; the auxiliary fiber filaments are made of the thermoplastic resin, and the main fiber filaments are reinforcing fibers.

[0020] mixing the auxiliary fiber filaments and the main fiber filaments to provide the wrapped yarn.

[0021] weaving the wrapped yarn to provide the fiber preform piece.

[0022] stacking the fiber preform pieces along the length direction to provide the fiber preform. In the wrapped yarn, the auxiliary fiber filaments are arranged to wrap the main fiber filaments, and the auxiliary fiber filaments extend spirally along the running direction of the main fiber filaments; the running direction of the main fiber filaments is the fiber orientation of the fiber preform piece.

[0023] Optionally, the reinforcing fibers in the fiber preform piece of the composite article are organic fibers or inorganic fibers.

[0024] Optionally, the inorganic fiber is one of glass fiber cloth, carbon fiber, basalt fiber, and quartz fiber; and the organic fiber is one of aramid fiber and ultra-high molecular weight polyethylene fiber.

[0025] Optionally, the thermoplastic resin is one of polyethylene, polypropylene, nylon, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, polyterephthalate resin, and polycarbonate.

[0026] Optionally, the nylon is one of polyamide-6, polyamide-66, long-chain nylon, and aromatic nylon.

[0027] Optionally, the unidirectional fiber prepreg sheet in the fiber prepreg product is divided into a first unidirectional fiber prepreg sheet and a second unidirectional fiber prepreg sheet; the first unidirectional fiber prepreg sheet is oriented in a first direction, and the second unidirectional fiber prepreg sheet is oriented in a second direction, the first direction, the second direction, and the length direction intersecting each other in pairs. The fiber prepreg product includes first prepreg sections and second prepreg sections alternately arranged along the length direction, the first prepreg sections including one first unidirectional fiber prepreg sheet or a plurality of first unidirectional fiber prepreg sheets stacked in sequence along the length direction; and the second prepreg sections including one second unidirectional fiber prepreg sheet or a plurality of second unidirectional fiber prepreg sheets stacked in sequence along the length direction.

[0028] Compared with the prior art, the application has the following beneficial effects:

[0029] The preparation method disclosed in the application is used for preparing a thermoplastic composite product. The composite product is formed in a mold cavity of an extrusion die. The extrusion die includes a feeding section, a hot pressing section, and a cooling section arranged in sequence in the mold cavity along a feeding direction of the mold cavity. The method includes the following steps.

[0030] The fiber prepreg product is provided to the feeding section.

[0031] The fiber prepreg product is transported to the hot pressing section.

[0032] The fiber prepreg product is heated to a temperature greater than or equal to a first preset temperature in the hot pressing section, so as to plasticize the fiber prepreg product, and the plasticized fiber prepreg product is compacted to provide the composite product.

[0033] The composite product is transported to the cooling section.

[0034] The composite product is cooled to a temperature less than or equal to a second preset temperature in the cooling section, so as to shape the composite product.

[0035] The second preset temperature is less than the first preset temperature; the fiber preform includes a plurality of fiber preform pieces stacked in sequence along a length direction, the fiber preform piece being one of a multidirectional fiber preform piece and a unidirectional fiber preform piece; the multidirectional fiber preform piece includes at least two kinds of fibers with intersecting fiber orientations and a thermoplastic resin; the unidirectional fiber preform piece includes one kind of fibers with consistent fiber orientations and a thermoplastic resin; the fiber preform includes at least two kinds of unidirectional fiber preform pieces with intersecting fiber orientations, or the fiber preform includes the multidirectional fiber preform piece; the length direction is consistent with a feeding direction, and the fiber orientation is perpendicular to the length direction; and the compaction direction is parallel to the length direction.

[0036] The composite product formed in this way has, in a first aspect, the fiber orientations of the fiber preform pieces therein being all normal orientations (perpendicular to the length direction), thereby improving the tensile strength, compressive strength and modulus and other properties of the composite product in the normal direction thereof.

[0037] In a second aspect, the new composite product is continuously generated at the input end of the mold cavity (i.e., the end where the feeding section is located) using the preparation method of the present application, and the composite product is continuously accumulated out of the mold at the output end of the mold cavity (i.e., the end close to the hot pressing section). It can be seen that the preparation method of the present application is more suitable for the extrusion molding of composite products in the form of bars, pipes or other similar structural profiles.

[0038] In a third aspect, compared with the composite product in the form of a plate, the thickness of the plate is limited by its processing equipment, and therefore the thickness of the plate cannot be too large, generally not exceeding 50 mm, while the composite product of the present application is used to prepare a bar or a pipe, and the length thereof can be adjusted as needed, such as 3000 mm, 5000 mm, etc., and the composite product of the present application has more advantages in size control than the plate.

[0039] In a fourth aspect, for a plate or other types of composite products, different processing procedures often need to be performed on different equipment, such as a compaction belt machine for compaction, an infrared heating device for heating and curing, etc. The change of procedures requires the product to be transferred between different equipment, while the composite product of the present application is completed from feeding to final molding in the extrusion mold, and therefore the product does not need to be transferred when the procedures are connected, thereby improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0041] Figure 1First state diagram of a process for manufacturing a composite article disclosed in the present application;

[0042] Figure 2 Second state diagram of a process for manufacturing a composite article disclosed in the present application;

[0043] Figure 3 Third state diagram of a process for manufacturing a composite article disclosed in the present application;

[0044] Figure 4 Fourth state diagram of a process for manufacturing a composite article disclosed in the present application;

[0045] Figure 5 Diagram of a process for manufacturing a composite article of a pipe structure disclosed in the present application;

[0046] Figure 6 Diagram of a process for manufacturing another composite article of a pipe structure disclosed in the present application;

[0047] Figure 7 Diagram of a first composite article structure composed of unidirectional fiber prepreg disclosed in the present application;

[0048] Figure 8 Diagram of a second composite article structure composed of unidirectional fiber prepreg disclosed in the present application;

[0049] Figure 9 Diagram of a third composite article structure composed of unidirectional fiber prepreg disclosed in the present application;

[0050] Figure 10 Diagram of a composite article structure composed of multidirectional fiber prepreg disclosed in the present application;

[0051] Figure 11 Diagram of a process for manufacturing a composite article of a pipe structure disclosed in the present application;

[0052] Figure 12 Diagram of a process for manufacturing a composite article of a pipe structure disclosed in the present application;

[0053] Explanation of reference numerals:

[0054] X - first direction, Y - second direction, Z - length direction,

[0055] 10 - composite article,

[0056] 11 - first unidirectional fiber prepreg, 12 - second unidirectional fiber prepreg, 13 - multidirectional fiber prepreg,

[0057] 101 - main fiber, 102 - auxiliary fiber,

[0058] 20 - mold cavity,

[0059] 21 - feeding section, 22 - hot pressing section, 23 - cooling section,

[0060] 201 - first pile extrusion mechanism, 202 - second pile extrusion mechanism, 203 - mandrel. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0062] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0063] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. Those skilled in the art can understand the specific meaning of these terms in the present application according to the specific situation.

[0064] In addition, the terms "mount", "set", "provided with", "connect", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two devices, elements or components. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific situation.

[0065] In addition, the terms "first", "second", and the like are mainly used to distinguish different devices, elements or components (the specific types and structures can be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "multiple" is two or more.

[0066] The forming of thermoplastic composites usually adopts processing methods such as injection molding, extrusion, and molding. Among them, the injection molding and extrusion processing are easy to break the fibers, affecting the final mechanical strength of the product; and the molding method has small damage to the fibers, but needs to prepare a prepreg in advance, so that the resin and the fibers are uniformly mixed in advance, such as related technologies can first prepare unidirectional cloth, thermoplastic resin is well infiltrated into unidirectional fibers to form a thin layer of cloth, or the fibers are impregnated with thermoplastic resin, and then the thermoplastic is heated and molded to prepare sheets, boards and the like.

[0067] In the related art, the unidirectional cloth impregnated with thermoplastic resin can also be heated and wound to prepare pipes or rods. Or, the processing method of extrusion is adopted, the thermoplastic resin and the fibers are mixed as processing raw materials, melted by an extruder, then cooled and shaped, and cut to a fixed length, but such processing will make the fibers be cut into short fibers (length <1mm), and the fiber orientation is random or preferentially oriented along the extrusion direction.

[0068] The strength of the composite product is closely related to the fiber orientation, and usually has higher tensile strength and modulus along the fiber direction, and better compression strength and modulus. In some special occasions, it is required that the profile has high compression and tensile resistance along the cross direction, but it is difficult to achieve by using the forming method in the related art. In summary, in order to improve the compression and tensile resistance of the composite product along the cross direction, the technical scheme of the present application is generated, which is described below in combination with Figures 1-12 .

[0069] The application discloses a preparation method of a thermoplastic composite product 10, and the composite product 10 is formed into a rod or a pipe in a die cavity 20 of an extrusion die. The extrusion die comprises a feeding section 21, a hot pressing section 22 and a cooling section 23 which are arranged in the die cavity 20 in sequence along a feeding direction of the die cavity 20, the feeding section 21 is arranged close to an input end of the die cavity 20, the cooling section 23 is arranged close to an output end of the die cavity 20, the feeding direction is from the input end of the die cavity 20 to the output end of the die cavity 20, the extrusion die is movably provided with a first piling and extruding mechanism 201 and a second piling and extruding mechanism 202, the die cavity 20 is located between the first piling and extruding mechanism 201 and the second piling and extruding mechanism 202, the first piling and extruding mechanism 201 is arranged towards a side of the die cavity 20 close to the feeding section 21, the second piling and extruding mechanism 202 is arranged towards a side of the die cavity 20 close to the cooling section 23, at least part of the first piling and extruding mechanism 201 and at least part of the second piling and extruding mechanism 202 can enter the die cavity 20, here, the first piling and extruding mechanism 201 and the second piling and extruding mechanism 202 can be selected from an electric push rod mechanism, a cylinder piston mechanism and the like, taking the cylinder piston mechanism as an example, a front end of a piston rod can be provided with a top plate, thus the top plate of the first piling and extruding mechanism 201 and the top plate of the second piling and extruding mechanism 202 can enter the die cavity 20, and the top plate of the first piling and extruding mechanism 201 and the top plate of the second piling and extruding mechanism 202 can approach each other to form extrusion on the composite product 10 in the die cavity 20, and the composite product 10 is gradually compacted to tightly adhere to an inner wall of the die cavity 20 in the extrusion process, so as to ensure that an outer shape of the composite product 10 is consistent with a shape of the die cavity 20, that is, the shape of the die cavity 20 determines the outer shape of the composite product 10, for example, the composite product 10 can be a pipe or a rod with various shapes such as a circular cross section, a rectangular cross section, a hexagonal cross section and the like.

[0070] The preparation method of the composite product 10 can comprise the following steps.

[0071] The feeding process is performed, that is, a fiber preform is provided to the feeding section 21. The fiber preform is a thermoplastic preform, thus the fiber preform has the forming characteristics of a thermoplastic material, that is, the fiber preform can be repeatedly heated, plasticized and cooled and hardened reversibly. Specifically, the fiber preform comprises a plurality of fiber preform pieces which are stacked in sequence along a length direction Z, and the fiber preform pieces are one of multidirectional fiber preform pieces and unidirectional fiber preform pieces. The multidirectional fiber preform piece comprises at least two kinds of fibers with intersecting fiber orientations and a thermoplastic resin; the unidirectional fiber preform piece comprises one kind of fibers with consistent fiber orientations and a thermoplastic resin. The fiber preform comprises at least two kinds of unidirectional fiber preform pieces with intersecting fiber orientations, or the fiber preform comprises multidirectional fiber preform pieces, for example, the fiber preform comprises only multidirectional fiber preform pieces, or the fiber preform comprises two or more kinds of unidirectional fiber preform pieces with different fiber orientations, and the fiber orientations of different kinds of unidirectional fiber preform pieces intersect, or the fiber preform comprises both multidirectional fiber preform pieces and unidirectional fiber preform pieces.

[0072] Performing a transfer process: controlling the first stack extrusion mechanism 201 to move in the length direction Z towards the rear, so as to transfer the fiber preform to the hot pressing section 22.

[0073] Performing a hot pressing process: heating the fiber preform to a first preset temperature in the hot pressing section 22, so as to plasticize the fiber preform, and the first stack extrusion mechanism 201 and the second stack extrusion mechanism 202 approach each other, so that the extrusion die compacts the plasticized fiber preform, so that the fiber preform gradually adheres to the inner wall of the mold cavity 20, so as to provide the composite product 10, as shown in Figure 1 The first preset temperature refers to the temperature at which the fiber preform containing thermoplastic material is heated to plasticize, such as the first preset temperature being the viscous flow temperature or melting temperature of the thermoplastic resin.

[0074] Performing a transfer process: controlling the first stack extrusion mechanism 201 to continue moving in the length direction Z, so as to transfer the composite product 10 from the hot pressing section 22 to the cooling section 23 by pushing.

[0075] Performing a curing process: cooling the composite product 10 to a second preset temperature in the cooling section 23, so as to shape the composite product 10, as shown in Figure 2 The second preset temperature refers to the temperature at which the composite product 10 can be cooled and hardened, such as the second preset temperature being the crystallization temperature or glass transition temperature of the thermoplastic resin. It can be understood that the second preset temperature is less than the first preset temperature.

[0076] It should be noted that after each transfer process, new fiber preforms can be added to the feeding section 21, as shown in Figure 3 The newly added fiber preforms are then transferred to the hot pressing section 22, and the hot pressing process is performed on the newly added fiber preforms, as shown in Figure 4 The newly added fiber preforms are then transferred to the hot pressing section 22, and the hot pressing process is performed on the newly added fiber preforms, as shown in

[0077] It should also be noted that since the composite material product 10 is continuously formed in the extrusion die, the transfer process specifically includes: controlling the movement of the first stacking mechanism 201 to transfer the fiber pre-product in the feeding section 21 to the hot pressing section 22, and transferring the composite material product 10 in the hot pressing section 22 to the cooling section 23, and pushing the composite material product 10 in the cooling section 23 out of the die.

[0078] After receiving their respective materials, the hot pressing section 22 and the cooling section 23 execute their corresponding processes. For example, the hot pressing section 22 receives fiber pre-products and the cooling section 23 receives composite material products 10. For example, the hot pressing section 22 executes the hot pressing process and the cooling section 23 executes the curing process. These will not be described in detail here.

[0079] Understandably, if the mold cavity 20 only contains the fiber preform in the hot pressing section 22, the first extrusion mechanism 201 and the second extrusion mechanism 202 directly contact the two opposite end faces of the fiber preform to plasticize and compact it. However, if the composite material product 10 is already present in the cooling section 23 of the mold cavity 20, and the fiber preform is already present in the feeding section 21 of the mold cavity 20, the first extrusion mechanism 201 transmits force through the fiber preform in the feeding section 21 to indirectly compress one side of the fiber preform in the hot pressing section 22, and the second extrusion mechanism 202 transmits force through the composite material product 10 in the cooling section 23 to indirectly compress the other side of the fiber preform in the hot pressing section 22, thereby plasticizing and compacting the fiber preform in the hot pressing section 22 to transform it into the composite material product 10. At this time, the composite material product 10 in the hot pressing section 22 will be connected to the end of the composite material product 10 in the cooling section 23.

[0080] The following are examples illustrating composite material products 10 composed of several different prepreg sections:

[0081] like Figures 7-9 As shown, the fiber preform can be composed of only two unidirectional fiber preforms with different fiber orientations, and the unidirectional fiber preforms in the fiber preform are divided into a first unidirectional fiber preform 11 and a second unidirectional fiber preform 12. The first unidirectional fiber preform 11 is oriented in a first direction X, and the second unidirectional fiber preform 12 is oriented in a second direction Y. The first direction X, the second direction Y, and the length direction Z intersect each other, for example, they are perpendicular to each other.

[0082] The fiber prepreg includes a first prepreg section and a second prepreg section arranged alternately along the length direction Z. The first prepreg section includes a first unidirectional fiber prepreg 11 or a plurality of first unidirectional fiber prepregs 11 stacked sequentially along the length direction Z. The second prepreg section includes a second unidirectional fiber prepreg 12 or a plurality of second unidirectional fiber prepregs 12 stacked sequentially along the length direction Z.

[0083] like Figure 7 As shown, in the structure of the first composite material product 10, the composite material product 10 is formed by alternating superposition of the first unidirectional fiber preform 11 and the second unidirectional fiber preform 12 along the length direction Z, that is, the first prepreg section includes only one first unidirectional fiber preform 11, and the second prepreg section includes only one second unidirectional fiber preform 12.

[0084] like Figure 8 As shown, in the structure of the second composite material article 10, the first prepreg section may include multiple first unidirectional fiber preforms 11, such as two first unidirectional fiber preforms 11, and the second prepreg section may include one second unidirectional fiber preform 12. The composite material article 10 thus formed is generated by alternatingly stacking the first unidirectional fiber preforms 11 and the second unidirectional fiber preforms 12 in a 2:1 ratio along the length direction Z.

[0085] like Figure 9 As shown, in the structure of the third composite material article 10, the first prepreg section may include a first unidirectional fiber preform 11, and the second prepreg section may include two second unidirectional fiber preforms 12. The composite material article 10 thus formed is generated by alternatingly stacking the first unidirectional fiber preform 11 and the second unidirectional fiber preform 12 in a 1:2 ratio along the length direction Z.

[0086] Of course, the first unidirectional fiber preform 11 and the second unidirectional fiber preform 12 can also be adjusted in other proportions to adjust the structure of the composite material product 10. By adjusting the proportions, the cross-sectional properties of the composite material product 10 in a specific direction can be adjusted. At the same time, the composite material product 10 can also be formed by stacking more fiber preforms with different fiber orientations to have better cross-sectional properties in more directions. Alternatively, the fiber preform can also be composed of three or more unidirectional fiber preforms with different fiber orientations, which will not be described in detail here.

[0087] Figure 12 Compared to the traditional compression molding methods used in related technologies for composite material products, the preparation method of this application has significant mechanical advantages in the cross-section parallel to the fiber preform, such as the first direction X and the second direction Y, as shown in the table below:

[0088]

[0089] The composite material product 10 formed in this way, in a first aspect, has the fibers of the fiber preform therein oriented in the cross direction (perpendicular to the length direction Z), thereby improving the tensile strength, compressive strength and modulus of the composite material product 10 in the cross direction.

[0090] In a second aspect, the new composite material product 10 is continuously generated at the input end of the mold cavity 20 (i.e. the end where the feeding section 21 is located) and continuously accumulated out of the mold at the output end of the mold cavity 20 (i.e. the end close to the hot pressing section 22) using the preparation method of the present application. It can be seen that the preparation method of the present application is more suitable for the extrusion molding of the composite material product 10 in the form of a bar, a pipe or other similar structural profiles.

[0091] In a third aspect, Figure 12 The preparation method in the related art disclosed is more suitable for the composite material product 10 in the form of a plate. Compared with the composite material product 10 in the form of a plate, the thickness of the plate is limited by the processing equipment and cannot be too large, generally not more than 50 mm. The composite material product 10 of the present application is used to prepare a bar or a pipe, and the length thereof can be adjusted as needed, such as 3000 mm, 5000 mm, etc. The composite material product 10 of the present application has more advantages in size control than the plate.

[0092] In a fourth aspect, for a plate or other types of composite material products, different processing procedures often need to be carried out on different equipment, such as using a pressure belt machine to realize compaction, using an infrared heating device to realize heating and curing, etc. The change of procedures requires the product to be transferred between different equipment. The composite material product 10 of the present application is completed from feeding to final molding in the extrusion mold, and does not need to be transferred during the connection of procedures, thereby improving the production efficiency.

[0093] In some other optional embodiments, Figure 10 For the fiber preform prepared by simply using the multidirectional fiber preform 13, the multidirectional fiber preform 13 contains not only the first fibers oriented in the first direction X, but also the second fibers oriented in the second direction Y, and the first fibers and the second fibers are interlaced in the multidirectional fiber preform 13, such as perpendicular to each other. In this way, since the fibers in the multidirectional fiber preform 13 are oriented in the cross direction (perpendicular to the length direction Z), the tensile strength, compressive strength and modulus of the composite material product 10 in the cross direction can also be improved.

[0094] It should be noted that, since the multidirectional fiber preform 13 has at least two intersecting fiber orientations, when the multidirectional fiber preform 13 is stacked, the multidirectional fiber preform 13 can be stacked in a manner as shown inFigure 10 As shown, when arranging the plurality of fibrous preforms 13, the first fibers of one portion of the plurality of fibrous preforms 13 can be arranged in the first direction X and the second fibers arranged in the second direction Y, and the first fibers of another portion of the plurality of fibrous preforms 13 can be arranged obliquely relative to the first direction X and the second fibers arranged obliquely relative to the second direction Y. In this way, compared with the way of preparing the composite material product 10 using the unidirectional fibrous preform, when preparing the composite material product 10 using the plurality of fibrous preforms 13, the arrangement direction of the fibers in the plurality of fibrous preforms 13 does not need to be considered deliberately, and the plurality of fibrous preforms 13 can be stacked directly in the length direction Z, which can improve the preparation efficiency. The stacking of the unidirectional fibrous preform can make the fibrous preform have better strength, and is more suitable for the composite material product 10 of the present application. Therefore, the producer can consider the composite material product 10 to be prepared using the plurality of fibrous preforms 13 or the unidirectional fibrous preform or the plurality of fibrous preforms and the unidirectional fibrous preform to be prepared in a certain proportion according to the needs, which will not be described in detail here.

[0095] In other optional embodiments, the preparation method of the present application is used to prepare the composite material product 10 in the form of a pipe, for example, a pipe for a water heater. Figures 1-4 In addition to the preparation of the composite material product 10 in the form of a rod, the preparation method of the present application can also be used to prepare the composite material product 10 in the form of a pipe, for example, a pipe for a water heater. Figure 5 As shown, in this way, the core rod 203 is arranged in the mold cavity 20 of the extrusion die, the fibrous preform is also annular and is sleeved on the core rod 203, and the top plate of the first stacking and extruding mechanism 201 and the top plate of the second stacking and extruding mechanism 202 are also sleeved on the core rod 203. In this way, when the hot pressing process is performed, the fibrous preform will be tightly attached to the outer periphery of the core rod 203 and the inner wall of the mold cavity 20 under the compression of the first stacking and extruding mechanism 201 and the second stacking and extruding mechanism 202, and then the composite material product 10 in the form of a pipe is obtained after the curing process. As shown in the figure, the core rod 203 is arranged in the mold cavity 20 of the extrusion die, the fibrous preform is also annular and is sleeved on the core rod 203, and the top plate of the first stacking and extruding mechanism 201 and the top plate of the second stacking and extruding mechanism 202 are also sleeved on the core rod 203. In this way, when the hot pressing process is performed, the fibrous preform will be tightly attached to the outer periphery of the core rod 203 and the inner wall of the mold cavity 20 under the compression of the first stacking and extruding mechanism 201 and the second stacking and extruding mechanism 202, and then the composite material product 10 in the form of a pipe is obtained after the curing process. Figure 6 As shown, the top plate of the first stacking and extruding mechanism 201 is sleeved on the core rod 203, and the top plate of the second stacking and extruding mechanism 202 is located on one side of the core rod 203 along the length direction Z, which can also achieve the compression of the composite material product 10.

[0096] Optionally, the preparation method of the present application can further include a demolding process: controlling the first stacking and extruding mechanism 201 to perform the stacking and extruding movement to push the composite material product 10 in the cooling section 23 out of the mold. Further, the extrusion die can also be provided with a cutting mechanism, such as a laser cutting device, a water jet cutting device, etc. at the end of the cooling section 23, which can cut the composite material product 10 after the composite material product 10 is extruded out of the mold cavity 20 to the required length, so as to facilitate the storage of the composite material product 10 according to the preset length.

[0097] Optionally, for the temperature control mode of the hot pressing section 22, heating can be performed by installing an electric heating jacket or an electric heating rod at the position of the mold cavity 20, and temperature control can be achieved by installing a temperature sensor; for the cooling mode of the cooling section 23, cooling can be achieved by circulating air cooling, liquid medium circulating cooling, etc., which will not be described in detail here.

[0098] The following further describes the specific embodiments of the present application by taking a composite material product 10 composed of basalt fibers and polyether ether ketone resin as an example, with the length of the composite material product 10 being 3 m, the width being 80 mm (the width direction being the second direction Y), and the thickness being 25 mm (the thickness direction being the first direction X), and the temperature being set as follows: the feeding section 21 is controlled at 100-300°C, the temperature of the hot pressing section 22 is controlled at 350-410°C (i.e., the range of the first preset temperature), and the temperature of the cooling section 23 is controlled at 50-145°C (i.e., the range of the second preset temperature), without limiting the present application to the described embodiments.

[0099] Example 1

[0100] The fiber preform is composed of first unidirectional fiber preform sheets 11 oriented in the first direction X and second unidirectional fiber preform sheets 12 oriented in the second direction Y, which are alternately stacked in a 1:1 ratio, with the content ratio of polyether ether ketone to basalt fibers being 40:60, and the temperature being set as follows: the temperature of the feeding section 21 = 100°C, the temperature of the hot pressing section 22 = 380°C, and the temperature of the cooling section 23 = 130°C, and the performance parameters of the obtained composite material product 10 are as follows:

[0101] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 630 Tensile strength along the second direction Y (MPa) 630 Bending strength along the second direction Y (MPa) 800 Bending modulus (GPa) 40 Compression strength along the second direction Y (MPa) 750 Compression modulus (GPa) 65

[0102] Example 2

[0103] The difference from Example 1 is that the temperature is set as follows: the temperature of the feeding section 21 = 200°C, the temperature of the hot pressing section 22 = 350°C, and the temperature of the cooling section 23 = 50°C, and the performance parameters of the obtained composite material product 10 are as follows:

[0104] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 610 Tensile strength along the second direction Y (MPa) 611 Bending strength along the second direction Y (MPa) 760 Bending modulus (GPa) 37 Compression strength along the second direction Y (MPa) 730 Compression modulus (GPa) 62

[0105] Example 3

[0106] The difference from Example 1 is that the temperature is set as follows: the temperature of the feeding section 21 = 300°C, the temperature of the hot pressing section 22 = 410°C, and the temperature of the cooling section 23 = 145°C, and the performance parameters of the obtained composite material product 10 are as follows:

[0107] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 635 Tensile strength along the second direction Y (MPa) 636 Bending strength along the second direction Y (MPa) 810 Bending modulus (GPa) 42 Compression strength along the second direction Y (MPa) 760 Compression modulus (GPa) 66

[0108] Example 4

[0109] The fiber preform was obtained by alternately stacking the first unidirectional fiber preform sheet 11 oriented in the first direction X and the second unidirectional fiber preform sheet 12 oriented in the second direction Y in a ratio of 2:1, wherein the content ratio of polyether ether ketone to basalt fiber = 40:60, and the set temperatures: the temperature of the feeding section 21 = 100°C, the temperature of the hot-pressing section 22 = 380°C, and the temperature of the cooling section 23 = 130°C. The performance parameters of the obtained composite product 10 are as follows:

[0110]

[0111]

[0112] Example 5

[0113] The difference from Example 4 is that the set temperatures: the temperature of the feeding section 21 = 200°C, the temperature of the hot-pressing section 22 = 350°C, and the temperature of the cooling section 23 = 50°C. The performance parameters of the obtained composite product 10 are as follows:

[0114] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 580 Tensile strength along the second direction Y (MPa) 460 Bending strength along the second direction Y (MPa) 640 Bending modulus (GPa) 28 Compression strength along the second direction Y (MPa) 600 Compression modulus (GPa) 50

[0115] Example 6

[0116] The difference from Example 4 is that the set temperatures: the temperature of the feeding section 21 = 300°C, the temperature of the hot-pressing section 22 = 410°C, and the temperature of the cooling section 23 = 145°C. The performance parameters of the obtained composite product 10 are as follows:

[0117]

[0118]

[0119] Example 7

[0120] The fiber preform was obtained by alternately stacking the first unidirectional fiber preform sheet 11 oriented in the first direction X and the second unidirectional fiber preform sheet 12 oriented in the second direction Y in a ratio of 1:2, wherein the content ratio of polyether ether ketone to basalt fiber = 40:60, and the set temperatures: the temperature of the feeding section 21 = 100°C, the temperature of the hot-pressing section 22 = 380°C, and the temperature of the cooling section 23 = 130°C. The performance parameters of the obtained composite product 10 are as follows:

[0121] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 600 Tensile strength along the second direction Y (MPa) 660 Bending strength along the second direction Y (MPa) 860 Bending modulus (GPa) 45 Compression strength along the second direction Y (MPa) 820 Compression modulus (GPa) 72

[0122] Example 8

[0123] The temperature was set as follows: temperature of the feeding section 21 = 200°C, temperature of the hot-pressing section 22 = 350°C, and temperature of the cooling section 23 = 50°C. The performance parameters of the resulting composite product 10 were as follows:

[0124]

[0125]

[0126] Example 9

[0127] The temperature was set as follows: temperature of the feeding section 21 = 300°C, temperature of the hot-pressing section 22 = 410°C, and temperature of the cooling section 23 = 145°C. The performance parameters of the resulting composite product 10 were as follows:

[0128] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 610 Tensile strength along the second direction Y (MPa) 650 Bending strength along the second direction Y (MPa) 865 Bending modulus (GPa) 46 Compression strength along the second direction Y (MPa) 830 Compression modulus (GPa) 73

[0129] Example 10

[0130] The fiber preform was made by stacking multiple unidirectional fiber preforms, which were made by interlacing fibers oriented in a first direction X and fibers oriented in a second direction Y in a 1:1 ratio, wherein the content ratio of polyether ether ketone to basalt fibers = 40:60. The temperature was set as follows: temperature of the feeding section 21 = 100°C, temperature of the hot-pressing section 22 = 380°C, and temperature of the cooling section 23 = 130°C. The performance parameters of the resulting composite product 10 were as follows:

[0131]

[0132]

[0133] Example 11

[0134] The temperature was set as follows: temperature of the feeding section 21 = 200°C, temperature of the hot-pressing section 22 = 350°C, and temperature of the cooling section 23 = 50°C. The performance parameters of the resulting composite product 10 were as follows:

[0135] Item Data Density (g / cm3) 1.90 Tensile strength along the first direction X (MPa) 480 Tensile strength along the second direction Y (MPa) 480 Bending strength along the second direction Y (MPa) 600 Bending modulus (GPa) 30 Compression strength along the second direction Y (MPa) 600 Compression modulus (GPa) 50

[0136] Example 12

[0137] The temperature was set as follows: temperature of the feeding section 21 = 300°C, temperature of the hot-pressing section 22 = 410°C, and temperature of the cooling section 23 = 145°C. The performance parameters of the resulting composite product 10 were as follows:

[0138]

[0139]

[0140] Optionally, taking the composite material product 10 containing polyether ether ketone as an example, the temperature of each section, but the temperature of each section in the mold cavity 20 is selected according to the material of the composite material product 10, taking the preparation of the composite material product 10 containing polyamide-6 as an example, the feeding section 21 of the extrusion die is controlled at 50-150℃, the temperature of the hot pressing section 22 is controlled at 220-280℃, and the temperature of the cooling section 23 is controlled at 30-100℃.

[0141] Optionally, the application also discloses a preparation method of a fiber preform. Specifically, the preparation of the fiber preform can be performed in an impregnation manner. The fiber preform formed in this way is a prepreg product. The fiber preform formed in this way is a prepreg tape. That is, before the fiber preform is provided to the feeding section 21, the preparation method of the application further comprises:

[0142] pre-impregnating a fiber cloth in a thermoplastic resin to provide a fiber preform. Here, the fiber cloth can be a multidirectional fiber cloth or a unidirectional fiber cloth. The multidirectional fiber cloth comprises at least two kinds of reinforcing fibers with intersecting fiber orientations. The unidirectional fiber cloth has consistent fiber orientations of the reinforcing fibers inside. Taking polyether ether ketone as an example, the polyether ether ketone is softened to form a liquid state at a temperature of 400℃, and then the fiber cloth is impregnated in the liquid state polyether ether ketone to obtain the fiber preform.

[0143] cutting the fiber preform according to a preset cross-sectional shape. For example, a scissors or a cutting die is used.

[0144] stacking the fiber preforms in sequence along the length direction Z to provide the fiber preform.

[0145] In this way, the liquid state thermoplastic resin can better wrap the fiber cloth and achieve good dispersion impregnation. The fiber cloth determines the fiber orientation of the fiber preform, and the preset cross-sectional shape is substantially consistent with the cross-sectional shape of the composite material product 10. For example, the preset cross-sectional shape is cut into a circular shape, a rectangular shape, a hexagonal shape, or a ring shape according to needs, so as to prepare the composite material product 10 with a circular cross-sectional shape, a rectangular cross-sectional shape, a hexagonal cross-sectional shape, or a ring cross-sectional shape. Meanwhile, the preset cross-sectional shape has a coincidence degree with the cross-sectional shape of the composite material product 10 greater than 95%, so as to facilitate the fiber preform to smoothly enter the feeding section 21 and tightly adhere to the inner wall of the mold cavity 20 after being compacted in the hot pressing section 22.

[0146] Optionally, the application also discloses another preparation method of a fiber preform. Specifically, the preparation of the fiber preform can be performed in a wrapped yarn manner. That is, before the fiber preform is provided to the feeding section 21, the preparation method of the application further comprises:

[0147] The auxiliary fiber yarn 102 and the main fiber yarn 101 are mixed to provide the wrapped yarn.

[0148] The auxiliary fiber yarn 102 and the main fiber yarn 101 are mixed to provide the wrapped yarn.

[0149] The wrapped yarn is woven to provide the fiber preform.

[0150] The fiber preform is cut according to the preset cross-sectional shape. For example, a scissors, a cutting die, etc.

[0151] The fiber preforms are stacked in sequence along the length direction Z to provide the fiber preform product.

[0152] In the wrapped yarn, the auxiliary fiber yarn 102 is arranged to wrap the main fiber yarn 101, and the auxiliary fiber yarn 102 extends spirally along the direction of the main fiber yarn 101. The direction of the main fiber yarn 101 is the fiber orientation of the fiber preform, as shown in detail in Figure 11 Generally, the fiber preform woven from the wrapped yarn has at least two intersecting fiber orientations inside, and the main fiber yarns of the fiber preform are arranged in a crisscross layout to form a woven cloth structure.

[0153] It can be understood that the fiber preform thus formed is guaranteed in the cross-direction performance by the main fiber yarn 101, and the auxiliary fiber yarn 102 containing the thermoplastic resin can be well mixed with the main fiber yarn 101 in advance, so that when the fiber preform product is subjected to the hot pressing process in the subsequent hot pressing section 22, the thermoplastic auxiliary fiber yarn 102 melts to infiltrate and coat the main fiber yarn 101 it wraps. Such a wrapped yarn method can achieve better mixing and dispersion effect compared with the pre-impregnation method, and thus the structure of the composite product 10 formed is more stable.

[0154] It should be noted that the main fiber yarns 101 can be arranged side by side and have consistent directions, so that the fiber preform formed is a unidirectional fiber preform.

[0155] Optionally, the reinforcing fibers in the fiber preform of the composite product 10 can be organic fibers or inorganic fibers. Specifically, the inorganic fibers can be one of glass fiber cloth, carbon fiber, basalt fiber, and quartz fiber; and the organic fibers can be one of aramid fiber and ultra-high molecular weight polyethylene fiber.

[0156] Optionally, the thermoplastic resin can be one of polyethylene, polypropylene, nylon, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer (LCP), polyterephthalate resin (such as PET) and polycarbonate (PC). The nylon can be one of polyamide-6 (PA6), polyamide-66 (PA66), long-chain nylon and aromatic nylon.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a thermoplastic composite material product (10), the composite material product (10) being formed in a mold cavity (20) of an extrusion die, the extrusion die comprising a feeding section (21), a hot-pressing section (22) and a cooling section (23) arranged in the mold cavity (20) in sequence along a feeding direction of the mold cavity (20), characterized in that, The extrusion die is movably provided with a first stack extrusion mechanism (201) arranged on one side close to the feeding section (21) and a second stack extrusion mechanism (202) arranged on one side close to the cooling section (23), and a die cavity (20) is located between the first stack extrusion mechanism (201) and the second stack extrusion mechanism (202), at least part of the first stack extrusion mechanism (201) and at least part of the second stack extrusion mechanism (202) can move in and out of the die cavity (20), The method comprises: cutting the fiber prepreg according to the preset cross-sectional shape; stacking the fiber prepregs in sequence along the length direction (Z) to form the fiber preform; providing the fiber preform to the feeding section (21); transporting the fiber preform to the hot pressing section (22) by the first stack extrusion mechanism (201); heating the fiber preform to a first preset temperature or above in the hot pressing section (22) to plasticize the fiber preform, and approaching the first stack extrusion mechanism (201) and the second stack extrusion mechanism (202) to compact the plasticized fiber preform to provide the composite product (10); transporting the composite product (10) to the cooling section (23) by the first stack extrusion mechanism (201); cooling the composite product (10) to a second preset temperature or below in the cooling section (23) to shape the composite product (10); wherein the second preset temperature is lower than the first preset temperature; the fiber preform comprises a plurality of fiber prepregs stacked in sequence along the length direction (Z), and the fiber prepregs are one of multidirectional fiber prepregs and unidirectional fiber prepregs; wherein the multidirectional fiber prepregs comprise at least two kinds of fibers with intersecting fiber orientations and thermoplastic resin; the unidirectional fiber prepregs comprise one kind of fibers with consistent fiber orientation and thermoplastic resin; the fiber preform comprises at least two kinds of the unidirectional fiber prepregs with intersecting fiber orientations, or the fiber preform comprises the multidirectional fiber prepregs; the fiber preform with the preset cross section can enter the feeding section (21) and be shaped closely to the inner wall of the die cavity (20) after being compacted in the hot pressing section (22); the length direction (Z) is consistent with the feeding direction, and the fiber orientation is perpendicular to the length direction (Z); the compacting direction is parallel to the length direction (Z).

2. The production method according to claim 1, characterized by, The first preset temperature is the viscous flow temperature or the melting temperature of the thermoplastic resin.

3. The preparation method according to claim 1, characterized in that, The second preset temperature is the crystallization temperature or the glass transition temperature of the thermoplastic resin.

4. The production method according to claim 1, characterized by, Before the step of providing the fiber preform to the feeding section (21), the method further comprises: pre-impregnating the fiber cloth in the thermoplastic resin to provide the fiber prepreg; the fiber cloth is multidirectional fiber cloth or unidirectional fiber cloth; the multidirectional fiber cloth comprises at least two kinds of reinforcing fibers with intersecting fiber orientations, and the unidirectional fiber cloth has consistent fiber orientation of the reinforcing fibers inside; stacking the fiber prepregs in sequence along the length direction (Z) to provide the fiber preform.

5. The preparation method according to claim 1, characterized in that, Before the step of providing the fiber preform to the feeding section (21), the method further comprises: providing auxiliary fiber filaments (102) and main fiber filaments (101); wherein the auxiliary fiber filaments (102) are made of the thermoplastic resin, and the main fiber filaments (101) are reinforcing fibers; spinning the auxiliary fiber filaments (102) and the main fiber filaments (101) to provide wrapped yarns; weaving the wrapped yarns to provide fiber preforms; stacking the fiber preforms along the length direction (Z) to provide the fiber preform; In the wrapped yarns, the auxiliary fiber filaments (102) are arranged to wrap the main fiber filaments (101), and the auxiliary fiber filaments (102) extend spirally along the orientation of the main fiber filaments (101), and the orientation of the main fiber filaments (101) is the fiber orientation of the fiber preform.

6. The production method according to claim 4 or 5, characterized by, The reinforcing fibers in the fiber preforms of the composite product (10) are organic fibers or inorganic fibers.

7. The production method according to claim 6, wherein The inorganic fibers are one of glass fiber cloth, carbon fiber, basalt fiber, and quartz fiber. The organic fibers are one of aramid fiber and ultra-high molecular weight polyethylene fiber.

8. The production method according to claim 4 or 5, characterized by, The thermoplastic resin is one of polyethylene, polypropylene, nylon, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, polyterephthalate resin, and polycarbonate.

9. The production method according to claim 8, characterized by, The nylon is one of polyamide-6, polyamide-66, long-chain nylon, and aromatic nylon.

10. The method of claim 1, wherein, The unidirectional fiber preforms in the fiber preform are divided into first unidirectional fiber preforms (11) and second unidirectional fiber preforms (12); the first unidirectional fiber preforms (11) are oriented in a first direction (X), and the second unidirectional fiber preforms (12) are oriented in a second direction (Y), and the first direction (X), the second direction (Y), and the length direction (Z) intersect with each other in pairs; The fiber preform comprises first pre-impregnation sections and second pre-impregnation sections arranged alternately along the length direction (Z), the first pre-impregnation sections comprise one first unidirectional fiber preform (11) or a plurality of first unidirectional fiber preforms (11) stacked along the length direction (Z) in sequence; and the second pre-impregnation sections comprise one second unidirectional fiber preform (12) or a plurality of second unidirectional fiber preforms (12) stacked along the length direction (Z) in sequence.

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