Composite sheet, laminated plate, preparation method of laminated plate and vehicle

Abstract

The invention relates to a composite sheet, a laminated plate, a preparation method of the laminated plate and a vehicle. The composite sheet comprises mixed fiber woven cloth and first thermoplastic resin attached to the mixed fiber woven cloth. Wherein the mixed fiber woven cloth is made of second thermoplastic resin and reinforcing fibers, the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1 is smaller than T2. The second thermoplastic resin is added into the mixed fiber woven cloth, so that the toughness of the mixed fiber woven cloth can be improved, the tensile strength and bending strength of the composite sheet can be improved, the isotropy between the first thermoplastic resin and the mixed fiber woven cloth can be improved, and the infiltration effect of the first thermoplastic resin is improved; the weight of the composite sheet can be reduced, and the strength of the composite sheet can be improved; by using the two thermoplastic resins with different melting points, the thermal stability of the composite sheet can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of continuous fiber reinforced thermoplastic composite materials, and in particular to a composite sheet, a laminate and a preparation method thereof, and a vehicle. Background Art

[0002] Compared with thermosetting composites, thermoplastic composites have the inherent advantages of being recyclable and reusable. The continuous fiber reinforced thermoplastic composites (CFRTP) obtained by impregnating continuous fibers with thermoplastic resins usually have excellent properties such as light weight and high strength, good impact resistance, easy repair after damage, and long-term preservation of prepregs. It is a research hotspot in the field of high-strength resin-based composite material development with the goal of "replacing steel with plastic, saving energy and reducing emissions", and has great application value and broad application prospects in the field of new energy vehicles.

[0003] In the prior art, continuous fiber reinforced thermoplastic composite sheets have been widely used. However, the performance of traditional composite sheets is often difficult to meet the complex and changing application requirements, especially in situations where high strength and good thermal stability are required, the limitations of traditional materials are more obvious. Summary of the invention

[0004] Embodiments of the present invention provide a composite sheet, a laminate, a method for preparing the same, and a vehicle, which can improve the strength and thermal stability of existing composite sheets to at least partially solve the above-mentioned technical problems.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a composite sheet is provided, comprising a mixed fiber woven cloth and a first thermoplastic resin attached to the mixed fiber woven cloth; wherein the material of the mixed fiber woven cloth comprises a second thermoplastic resin and reinforcing fibers, the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1<T2.

[0006] Optionally, the melting point T1 of the first thermoplastic resin and the melting point T2 of the second thermoplastic resin satisfy: T2-T1≥30°C.

[0007] Optionally, the mixed fiber woven cloth includes resin fiber filaments and reinforcing fiber filaments;

[0008] The material of the resin fiber filaments includes the second thermoplastic resin, and the material of the reinforcing fiber filaments includes the reinforcing fibers.

[0009] Optionally, the mixed fiber woven cloth comprises mixed fiber filaments;

[0010] Wherein, the material of the mixed fiber filaments includes the second thermoplastic resin and the reinforcing fiber.

[0011] Optionally, the mixed fiber woven cloth comprises first fiber filaments and second fiber filaments which are cross-arranged, the first fiber filaments comprise the resin fiber filaments, and the second fiber filaments comprise the reinforcing fiber filaments; or

[0012] The mixed fiber woven cloth comprises first fiber filaments and second fiber filaments arranged crosswise, the first fiber filaments comprise the resin fiber filaments and the reinforcing fiber filaments, and the second fiber filaments comprise the reinforcing fiber filaments; or

[0013] The mixed fiber woven cloth includes first fiber filaments and second fiber filaments that are cross-arranged, and both the first fiber filaments and the second fiber filaments include the resin fiber filaments and the reinforcing fiber filaments.

[0014] Optionally, the diameter of the reinforcing fiber is 5 to 30 μm; and / or

[0015] The ratio of the diameter of the resin fiber filament to the diameter of the reinforcing fiber filament is (1-2):1.

[0016] Optionally, the weaving density of the resin fiber filaments in the mixed fiber woven cloth is greater than the weaving density of the reinforcing fiber filaments; and / or

[0017] The total content of the first thermoplastic resin and the second thermoplastic resin in the composite sheet is 50% or more.

[0018] Optionally, the thickness of the composite sheet is ≥0.1 mm; and / or

[0019] The weight of the mixed fiber woven cloth is 250-300 g / m 2 .

[0020] Optionally, the reinforcing fiber includes one or more of glass fiber, carbon fiber, Kevlar fiber, metal fiber, and natural fiber; and / or

[0021] The first thermoplastic resin and the second thermoplastic resin independently include one or more of polyethylene, polypropylene, nylon 6, nylon 66, polycarbonate, polyethylene terephthalate, polyetheretherketone, polystyrene, polybutylene terephthalate, polyester, polytetrafluoroethylene, low-density polyethylene, linear low-density polyethylene, polyphenylene sulfide, thermoplastic polyurethane elastomer, polyolefin elastomer and high-density polyethylene; and / or

[0022] The composite sheet also includes a compatibilizer.

[0023] According to a second aspect of the present application, a method for preparing a composite sheet is provided, comprising the following steps:

[0024] Providing a second thermoplastic resin and reinforcing fiber filaments, and making the second thermoplastic resin and the reinforcing fiber filaments into a mixed fiber woven cloth;

[0025] A first thermoplastic resin is provided and disposed on the mixed fiber woven cloth to obtain a composite sheet, wherein the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1<T2.

[0026] Optionally, the step of making the second thermoplastic resin and the reinforcing fiber filaments into a mixed fiber woven cloth comprises:

[0027] The second thermoplastic resin is made into resin fiber filaments, and the resin fiber filaments and the reinforcing fiber filaments are woven into a mixed fiber woven cloth; or

[0028] The reinforcing fiber yarn is impregnated in the second thermoplastic resin to obtain a mixed fiber yarn; or the second thermoplastic resin is made into a resin fiber yarn, and the reinforcing fiber yarn is wrapped with the resin fiber yarn to obtain a mixed fiber yarn; and the mixed fiber yarn is woven into a mixed fiber woven cloth.

[0029] Optionally, providing a first thermoplastic resin and placing the first thermoplastic resin on the mixed fiber woven cloth comprises:

[0030] A first thermoplastic resin and a compatibilizer are provided and mixed, and the mixed first thermoplastic resin and the compatibilizer are arranged on the mixed fiber woven cloth.

[0031] Optionally, the first thermoplastic resin is disposed on the mixed fiber woven cloth to obtain a composite sheet, comprising:

[0032] The first thermoplastic resin is heated to a molten state, the mixed fiber woven fabric is immersed in the molten first thermoplastic resin, and then taken out and solidified to obtain a composite sheet; or

[0033] The first thermoplastic resin is made into a film, and the film is laminated and pressed with the mixed fiber woven cloth to obtain a composite sheet.

[0034] According to a third aspect of the present application, a laminate is provided, comprising the above-mentioned composite sheet.

[0035] According to a fourth aspect of the present application, a method for preparing a laminate is provided, comprising the following steps:

[0036] A metal plate and at least one layer of the above-mentioned composite sheet are provided, or multiple layers of composite sheets are provided, and the layers are stacked, heated to soften, and pressed to obtain a laminate.

[0037] Optionally, the heating softening temperature T satisfies: T1 <T<T2。

[0038] The composite sheet of the embodiment of the present application can increase the toughness of the mixed fiber woven cloth by adding a second thermoplastic resin to the mixed fiber woven cloth, thereby improving the tensile strength and bending strength of the composite sheet, so that it can withstand greater mechanical stress; by using two thermoplastic resins with different melting points, the thermal stability of the composite sheet can be improved, so that it can still maintain excellent mechanical properties in a high temperature environment; by adding the second thermoplastic resin to the mixed fiber woven cloth, the isotropy between the first thermoplastic resin and the mixed fiber woven cloth can be improved, thereby improving the impregnation effect of the first thermoplastic resin; by adding the second thermoplastic resin to the mixed fiber woven cloth, the strength of the second thermoplastic resin is similar to that of the reinforcing fiber and the density is smaller than that of the reinforcing fiber, thereby reducing the weight of the composite sheet and improving the strength of the composite sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 is a schematic structural diagram of a composite sheet provided by an embodiment of the present invention;

[0041] Figure 2 is a schematic structural diagram of a mixed fiber woven fabric provided by an embodiment of the present invention;

[0042] Figure 3 Schematic diagrams of three weaving methods of mixed fiber woven fabrics provided by embodiments of the present invention;

[0043] Figure 4 is a flow chart of a method for preparing a composite sheet provided by an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of a preparation process of a laminate provided by an embodiment of the present invention;

[0045] Figure 6 is a schematic diagram of a preparation process of a laminate provided by an embodiment of the present invention;

[0046] Figure 7 is a schematic structural diagram of a laminate provided by an embodiment of the present invention;

[0047] Figure 8 is a surface effect diagram of the laminate provided in Example 1 of the present invention;

[0048] Fig. 9 It is a surface effect diagram of the laminate provided by Comparative Example 4 of the present invention;

[0049] Fig.10 It is a surface effect diagram of the laminate provided in Comparative Example 5 of the present invention. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device.

[0051] At present, there are two main types of CFRTP used in the field of new energy vehicles. One is a unidirectional tape obtained by pre-impregnating unidirectional continuous fibers with thermoplastic resins. It can be cross-stacked in multiple directions when used. Since there is no bonding force between the fibers and between different fiber layers, its mechanical properties are still insufficient. Therefore, pre-impregnated sheets reinforced with woven fibers have been developed. When manufacturing such materials, continuous fiber woven cloth can be directly used to impregnate the resin, or the resin fiber can be first used to wrap the reinforcing fiber to obtain a mixed fiber filament, or the reinforcing fiber filament can be pre-impregnated with resin to obtain a pre-impregnated monofilament, and then the above-mentioned mixed fiber filaments or pre-impregnated monofilaments are woven to obtain a composite sheet reinforced in two directions.

[0052] In addition, the weight-to-strength ratio of existing composite sheets still needs to be optimized to meet the growing demand for lightweight and high-strength materials.

[0053] The technical solution of this application is as follows:

[0054] See also Figure 1-3 , first of all, such as Figure 1 The figure is a schematic diagram of a structure of a composite sheet provided by an embodiment of the present invention. The embodiment of the present application provides a composite sheet, comprising a mixed fiber woven cloth and a first thermoplastic resin attached to the mixed fiber woven cloth, wherein the material of the mixed fiber woven cloth comprises a second thermoplastic resin and reinforcing fibers, wherein the melting point of the first thermoplastic resin is T1, and the melting point of the second thermoplastic resin is T2, and T1<T2.

[0055] In the present application, by adding a second thermoplastic resin to the mixed fiber woven cloth, the toughness of the mixed fiber woven cloth can be increased, thereby improving the tensile strength and bending strength of the composite sheet, so that it can withstand greater mechanical stress; by using two thermoplastic resins with different melting points, the thermal stability of the composite sheet can be improved, so that it can still maintain excellent mechanical properties in a high temperature environment; by adding a second thermoplastic resin to the mixed fiber woven cloth, the isotropy between the first thermoplastic resin and the mixed fiber woven cloth can be improved, thereby improving the impregnation effect of the first thermoplastic resin; by adding a second thermoplastic resin to the mixed fiber woven cloth, its strength is similar to that of the reinforcing fiber and its density is lower than that of the reinforcing fiber, thereby reducing the weight of the composite sheet and improving the strength of the composite sheet.

[0056] In some embodiments, the melting point T1 of the first thermoplastic resin and the melting point T2 of the second thermoplastic resin satisfy: T2-T1≥30°C.

[0057] In this application, when processing to form a composite sheet, the first thermoplastic resin needs to be heated to a molten state. The heating temperature is theoretically its melting point. However, in actual experiments or production processes, due to equipment errors, energy loss, resin impurities and other issues, and in order to improve heating efficiency and match a faster production cycle, the heating temperature usually needs to be 20 to 30°C higher than its actual melting point (empirical value). In order to make the composite sheet have good formability, the second thermoplastic resin cannot melt when the first thermoplastic resin melts. By making the melting point of the second thermoplastic resin at least 30°C higher than the melting point of the first thermoplastic resin, it can be prevented from melting at the selected heating temperature.

[0058] In the present application, the first thermoplastic resin may have a melting point of T L1 、T L2 、T L3 ,…,T LN The second thermoplastic resin may also be a mixture of several resins having melting points T H1 、T H2 、T H3 ,…,T HN If it is mixed with several resins, it should meet the MIN(T H1 、T H2 、T H3 ,…,T HN )-MAX(T L1 、T L2 、T L3 ,…,T LN )≥30°C, that is, the minimum value of the melting points of several resins in the first thermoplastic resin is at least 30°C greater than the maximum value of the melting points of several resins in the second thermoplastic resin.

[0059] In some embodiments, the melting point T1 of the first thermoplastic resin and the melting point T2 of the second thermoplastic resin satisfy: T2-T1≥50°C.

[0060] In the present application, the first thermoplastic resin may have a melting point of T L1 , T L2 , T L3 ,…,T LN The second thermoplastic resin may also be a mixture of several resins having melting points T H1 , T H2 , T H3 ,…,T HN If it is mixed with several resins, it should meet the MIN(T H1 , T H2 , T H3 ,…,T HN )-MAX(T L1 , T L2 , T L3 ,…,T LN )≥50℃.

[0061] In some embodiments, the mixed fiber woven cloth includes resin fiber filaments and reinforcing fiber filaments;

[0062] The material of the resin fiber filaments includes the second thermoplastic resin, and the material of the reinforcing fiber filaments includes the reinforcing fibers.

[0063] In the present application, the mixed fiber woven fabric can be woven from fiber filaments made of the second thermoplastic resin and the reinforcing fiber. The resin fiber filaments can be obtained by a melt spinning process. The weaving method of the resin fiber filaments and the reinforcing fiber filaments can be any one of plain weave, satin weave or twill weave (such as Figure 3 shown).

[0064] like Figure 2 FIG. 1 is a schematic diagram of a structure of a mixed fiber woven cloth provided in an embodiment of the present invention. In some embodiments, the mixed fiber woven cloth comprises a first fiber filament and a second fiber filament arranged crosswise, the first fiber filament comprises the resin fiber filament, and the second fiber filament comprises the reinforcing fiber filament.

[0065] In the present application, the first fiber filaments and the second fiber filaments arranged crosswise may be perpendicular to each other, or may be at an angle less than 90°.

[0066] like Figure 2, which is a schematic diagram of the structure of a mixed fiber woven cloth provided by an embodiment of the present invention. In some embodiments, the mixed fiber woven cloth includes a first fiber filament and a second fiber filament arranged crosswise, the first fiber filament includes the resin fiber filament and the reinforcing fiber filament, and the second fiber filament includes the reinforcing fiber filament.

[0067] In the present application, the first fiber filaments and the second fiber filaments arranged crosswise may be perpendicular to each other, or may be at an angle less than 90°.

[0068] like Figure 2 , which is a schematic diagram of the structure of a mixed fiber woven cloth provided by an embodiment of the present invention. In some embodiments, the mixed fiber woven cloth comprises a first fiber filament and a second fiber filament arranged crosswise, and the first fiber filament and the second fiber filament both comprise the resin fiber filament and the reinforcing fiber filament.

[0069] In the present application, by replacing the reinforcing fiber filaments with resin fiber filaments in two directions, the weight of the composite sheet can be reduced while ensuring the mechanical strength of the composite sheet; at the same time, the resin fiber filaments and the reinforcing fiber filaments are completely mixed, which also helps to increase the wettability of the first thermoplastic resin and improve the temperature adaptability of the composite sheet. The crossed first fiber filaments and the second fiber filaments can be perpendicular to each other or have an angle less than 90°.

[0070] In some embodiments, the diameter of the reinforcing fiber filament is 5-30 μm. Within the above range, the strength and toughness of the fiber filament can be good. If the fiber filament is too thin, the strength may not be enough, and if it is too thick, the toughness is poor.

[0071] In some embodiments, the ratio of the diameter of the resin fiber filament to the diameter of the reinforcing fiber filament is (1-2): 1. Within the range, the mechanical properties of the resin fiber filament and the mechanical properties of the reinforcing fiber filament can be ensured to match, so as to prevent deformation and other problems caused by asymmetric properties.

[0072] In some embodiments, the weaving density of the resin fiber filaments in the mixed fiber woven cloth is greater than the weaving density of the reinforcing fiber filaments.

[0073] In the present application, there is a difference in shrinkage rate between the resin fiber filaments and the reinforcing fiber filaments. Generally, the shrinkage rate of the resin fiber filaments is greater than that of the reinforcing fiber filaments. By making the resin fiber filaments denser, their higher shrinkage rate can be compensated and the deformation amount can be reduced.

[0074] In some embodiments, the weaving density of the resin fiber filaments in the mixed fiber woven cloth is more than twice that of the reinforcing fiber filaments.

[0075] In some embodiments, the weaving density of the resin fiber filaments in the mixed fiber woven cloth is more than 4 times that of the reinforcing fiber filaments.

[0076] In some embodiments, the weight of the mixed fiber woven fabric is 250-300 g / m 2 .

[0077] In some embodiments, the mixed fiber woven cloth includes mixed fiber filaments;

[0078] Wherein, the material of the mixed fiber filaments includes the second thermoplastic resin and the reinforcing fiber.

[0079] In the present application, the mixed fiber woven cloth can be woven from fiber filaments made of a second thermoplastic resin and reinforcing fibers. For example, the fiber filaments made of reinforcing fibers can be wrapped with the fiber filaments made of the second thermoplastic resin to obtain mixed fiber filaments, and the fiber filaments made of reinforcing fibers can be pre-impregnated with the second thermoplastic resin to obtain pre-impregnated monofilaments, and the obtained mixed fiber filaments and / or pre-impregnated monofilaments can be woven to obtain a mixed fiber woven cloth.

[0080] In some embodiments, the reinforcing fiber includes one or more of glass fiber, carbon fiber, Kevlar fiber (aramid fiber), metal fiber, and natural fiber.

[0081] In this application, natural fiber refers to bamboo fiber, cotton fiber and the like.

[0082] In some embodiments, the first thermoplastic resin and the second thermoplastic resin independently include one or more of polyethylene, polypropylene, nylon 6, nylon 66, polycarbonate, polyethylene terephthalate, polyetheretherketone, polystyrene, polybutylene terephthalate, polyester, polytetrafluoroethylene, low-density polyethylene, linear low-density polyethylene, polyphenylene sulfide, thermoplastic polyurethane elastomer (TPU), polyolefin elastomer (POE) and high-density polyethylene.

[0083] In some embodiments, the first thermoplastic resin includes one or more of polyethylene, high-density polyethylene, polypropylene and nylon 6.

[0084] In some embodiments, the second thermoplastic resin includes one or more of nylon 66, polycarbonate, polyethylene terephthalate, polyetheretherketone, polyphenylene sulfide, polystyrene, polybutylene terephthalate and polytetrafluoroethylene.

[0085] In some embodiments, the thickness of the composite sheet is ≥ 0.1 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, etc.

[0086] In the present application, the thickness of the composite sheet is determined by the thickness of the impregnating resin and the thickness of the mixed fiber woven cloth. The thickness of the mixed fiber woven cloth is determined by its surface density and fiber diameter / linear density. The greater the thickness of the impregnating resin, the higher the resin impregnation amount, which can improve the molding quality of the composite sheet.

[0087] In some embodiments, the total content of the first thermoplastic resin and the second thermoplastic resin in the composite sheet is greater than 50%. Within the range, a high resin content is beneficial to the molding of the composite sheet and can improve the surface quality of the composite sheet.

[0088] In some embodiments, the composite sheet further includes a compatibilizer.

[0089] In the present application, the compatibilizer can increase the compatibility of the first thermoplastic resin with the second thermoplastic resin and the reinforcing fiber. The compatibilizer can cause a "coupling" effect between different types of molecules, which can be a physical process (such as polarity effect, intermolecular force) or a chemical process (such as PP compatibilizer (PP-g-MAH) can use the anhydride bond -C(=O)-OC(=O)- or -COOH in MAH to react with the hydroxyl -OH or free amino group -NH2 in other molecules).

[0090] In some embodiments, the compatibilizer includes a maleic anhydride type compatibilizer, a carboxylic acid type compatibilizer, an epoxy type compatibilizer, an oxazoline type compatibilizer, an imide type compatibilizer, a low molecular weight type compatibilizer, and an isocyanate type compatibilizer.

[0091] In the present application, the maleic anhydride type compatibilizer is prepared by grafting maleic anhydride molecules onto a first thermoplastic resin.

[0092] In some embodiments, the mass of the compatibilizer is 0.1-10% of the mass of the first thermoplastic resin. Within the above range, a good compatibilization effect can be achieved while controlling the cost.

[0093] Second, see Figure 4 , is a flow chart of a method for preparing a composite sheet provided by an embodiment of the present invention. The present application embodiment provides a method for preparing a composite sheet, comprising the following steps:

[0094] S1. providing a second thermoplastic resin and reinforcing fiber filaments, and making the second thermoplastic resin and the reinforcing fiber filaments into a mixed fiber woven cloth;

[0095] S2. Provide a first thermoplastic resin, and place the first thermoplastic resin on the mixed fiber woven cloth to obtain a composite sheet, wherein the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1<T2.

[0096] In step S1,

[0097] In some embodiments, the step of preparing a mixed fiber woven cloth from the second thermoplastic resin and the reinforcing fiber filaments comprises:

[0098] The second thermoplastic resin is made into resin fiber yarns, and the resin fiber yarns and the reinforcing fiber yarns are woven into a mixed fiber woven cloth.

[0099] In the present application, the method of making the second thermoplastic resin into resin fiber yarns can adopt a melt spinning process. The weaving method of the resin fiber yarns and the reinforcing fiber yarns can be any one of plain weave, satin weave or twill weave.

[0100] In some embodiments, the weaving directions of the resin fiber filaments and the reinforcing fiber filaments are perpendicular.

[0101] In some embodiments, one of the transverse fiber filaments and the longitudinal fiber filaments of the mixed fiber woven cloth includes the resin fiber filaments and the reinforcing fiber filaments, and the other includes the reinforcing fiber filaments.

[0102] In some embodiments, both the transverse fiber filaments and the longitudinal fiber filaments of the mixed fiber woven cloth include the resin fiber filaments and the reinforcing fiber filaments.

[0103] In some embodiments, the step of preparing a mixed fiber woven cloth from the second thermoplastic resin and the reinforcing fiber comprises:

[0104] The second thermoplastic resin is made into resin fiber yarn, and the reinforcing fiber yarn is wrapped with the resin fiber yarn to obtain mixed fiber yarn;

[0105] The mixed fiber filaments are woven into mixed fiber woven cloth.

[0106] In some embodiments, the step of preparing a mixed fiber woven cloth from the second thermoplastic resin and the reinforcing fiber comprises:

[0107] impregnating the reinforcing fiber filaments into the second thermoplastic resin to obtain mixed fiber filaments;

[0108] The mixed fiber filaments are woven into mixed fiber woven cloth.

[0109] In step S2,

[0110] In some embodiments, providing a first thermoplastic resin and disposing the first thermoplastic resin on the mixed fiber woven cloth comprises:

[0111] A first thermoplastic resin and a compatibilizer are provided and mixed, and the mixed first thermoplastic resin and the compatibilizer are arranged on the mixed fiber woven cloth.

[0112] In some embodiments, the first thermoplastic resin is disposed on the mixed fiber woven cloth to obtain a composite sheet, comprising:

[0113] The first thermoplastic resin is heated to a molten state, the mixed fiber woven fabric is immersed in the molten first thermoplastic resin, and then taken out and solidified to obtain a composite sheet.

[0114] In the present application, the first thermoplastic resin is heated to a molten state, which can achieve effective impregnation of the mixed fiber woven cloth. At the same time, since the melting point of the first thermoplastic resin is lower than the melting point of the second thermoplastic resin, when the first thermoplastic resin is in a molten state, the second thermoplastic resin can still maintain a rigid structure with a certain toughness, thereby playing a supporting role and facilitating transfer after impregnation.

[0115] In some embodiments, the immersion time is 10 s to 5 min.

[0116] In the present application, the impregnation can be continuous impregnation or discontinuous impregnation. Continuous impregnation means that the mixed fiber woven cloth continuously passes through the glue tank containing the molten first thermoplastic resin to obtain a rolled composite resin sheet, and the continuous impregnation time is 10 to 30 seconds. Discontinuous impregnation refers to discontinuous production, for example, a piece of mixed fiber woven cloth of a specific area is directly impregnated with resin to obtain a single composite sheet, and the discontinuous impregnation time is 1 to 5 minutes.

[0117] In some embodiments, the first thermoplastic resin is disposed on the mixed fiber woven cloth to obtain a composite sheet, comprising:

[0118] The first thermoplastic resin is made into a film, and the film is laminated and pressed with the mixed fiber woven cloth to obtain a composite sheet.

[0119] In the present application, the method of making the first thermoplastic resin into a film may be an extrusion casting method, and the pressing method may be a hot pressing method or a roll pressing method.

[0120] In some embodiments, the lamination includes: laminating adhesive films on both sides of the mixed fiber woven cloth.

[0121] In the present application, the stacking method can be carried out in the form of "adhesive film + mixed fiber woven cloth + adhesive film", wherein the resin adhesive film can be stacked in one or more layers.

[0122] The types and parameters of materials used in the method for preparing the composite sheet in the present application are as described above.

[0123] Third, see Figure 7, which is a schematic diagram of a structure of a laminate provided in an embodiment of the present invention. The present application provides a laminate, comprising at least one layer of the above-mentioned composite sheet. The laminate of the present application can be used as a bottom protective plate of a power battery pack, such as Figure 7 As shown, it may include two layers of composite sheet material with a metal plate therebetween.

[0124] Fourth, please refer to Figure 5 , 6 , is a schematic diagram of a preparation process of a laminate provided by an embodiment of the present invention. The present application embodiment provides a method for preparing a laminate, comprising the following steps:

[0125] At least one layer of composite sheet and metal plate is provided, or multiple layers of composite sheets are provided, stacked, heated to soften, and pressed to obtain a laminate.

[0126] In the present application, the metal plate may be a steel plate or an aluminum plate, and the steel plate may be a surface-treated steel plate, such as an electrophoretic steel plate, a PVC-sprayed steel plate, a galvanized steel plate, and the like.

[0127] In some embodiments, the heating softening temperature T satisfies: T1 <T<T2。

[0128] In the present application, the compression molding of the laminate generally adopts the hot material cold mold process, so the composite sheet needs to be heated to a softened / melted state and then moved into the mold for compression molding. If the temperature is too low, the first thermoplastic resin is not completely softened, making it difficult or impossible to perform compression molding; if the temperature is too high, the first thermoplastic resin is converted into a fluid and cannot be transferred, and the resin may also undergo thermal decomposition; at this temperature, the first thermoplastic resin is in a molten but not dripping state, which can make the impregnated mixed fiber woven cloth have a certain softness to facilitate compression molding.

[0129] In some embodiments, the pressing is molding, and the temperature of the mold for the molding is from room temperature to 120°C.

[0130] In the present application, the compression molding of the laminate generally adopts the hot material cold mold process. The softened resin should follow the shape and harden into shape after contacting the mold surface. If the mold temperature is too high, although the conformability is improved, the softened resin will re-harden and mold slowly, and the production efficiency will be low. If the mold temperature is too low, the softened resin will harden rapidly after contacting the mold surface, making it difficult to follow the shape, and the molding effect is poor.

[0131] In some embodiments, the mold temperature of the molding is 60°C-120°C.

[0132] In some embodiments, the molding pressure is 2.5 MPa-20 MPa.

[0133] In the present application, if the molding pressure is too low, the molding effect and molding quality will be poor, and if the holding pressure is too high, the reinforcing fibers may be broken.

[0134] In some embodiments, the molding pressure is 5 MPa-15 MPa.

[0135] In some embodiments, the holding time of the molding is 1-10 minutes. Within the above range, the resin can be completely molded and hardened, and the molding effect is good.

[0136] In some embodiments, the holding time of the molding is 2 to 5 minutes.

[0137] In some embodiments, the compounding includes heating and softening and roll forming.

[0138] In a fifth aspect, an embodiment of the present application provides a vehicle, comprising the above-mentioned composite sheet or the above-mentioned laminate. When the laminate is used as a bottom guard plate of a power battery pack, it can be placed at the bottom of a battery pack tray to protect the battery pack from external impact.

[0139] Example 1

[0140] A composite sheet and a preparation method thereof, comprising the following steps:

[0141] (1) Commercially available nylon (PA66) fiber yarn (diameter: 20 μm, melting point: 252°C) and commercially available E-type alkali-free glass fiber yarn (diameter: 17 μm) were woven according to a plain weave method (the direction of the E-type alkali-free glass fiber yarn was the same as the pulling direction of the weaving machine, i.e., M-type, and the direction of the PA66 fiber yarn was the same as the pulling direction of the weaving machine, i.e., T-type), to obtain a mixed fiber woven fabric (the weaving density of the PA66 fiber yarn was twice that of the E-type alkali-free glass fiber yarn, and the gram weight of the mixed fiber woven fabric was 280 g / m 2 );

[0142] (2) 100 parts of polypropylene (PP) (melting point: 170°C) and 5 parts by mass of PP compatibilizer (PP-g-MAH) were mixed and heated to a molten state, and the mixed fiber woven fabric was immersed in it for 20 seconds to obtain a 0.2 mm thick composite sheet (the content of PA66 and PP is 55%).

[0143] A laminate and a preparation method thereof, comprising the following steps: stacking the above-mentioned composite sheets in the manner of M-type-T-M-type-T-type, heating and softening at 220°C, and then transferring them into a mold at 70°C, and pressing them at 10MPa and maintaining the pressure for 2 minutes to obtain a laminate with a thickness of about 0.8mm (such as Figure 8 shown).

[0144] Example 2

[0145] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the nylon (PA66) fiber filaments are replaced with polybutylene terephthalate (PBT) fiber filaments (melting point: 230° C.).

[0146] Example 3

[0147] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the nylon (PA66) fiber filaments are replaced with polyphenylene sulfide (PPS) fiber filaments (melting point: 280° C.).

[0148] Example 4

[0149] This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the weaving density of the PA66 fiber filaments is three times that of the E-type alkali-free glass fiber filaments.

[0150] Example 5

[0151] This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the weaving density of the PA66 fiber filaments is 5 times that of the E-type alkali-free glass fiber filaments.

[0152] Example 6

[0153] This embodiment is substantially the same as Embodiment 1, except that the content of PA66 and PP in this embodiment is 50%.

[0154] Example 7

[0155] This embodiment is substantially the same as Embodiment 1, except that the content of PA66 and PP in this embodiment is 60%.

[0156] Example 8

[0157] This embodiment is basically the same as Embodiment 1, except that, in this embodiment, the composite sheets are stacked in the manner of M-shape-T-steel plate-M-shape-T-shape.

[0158] Comparative Example 1

[0159] This comparative example is basically the same as Example 1, except that the PA66 fiber filaments are replaced with polypropylene (PP) fiber filaments in this comparative example.

[0160] Comparative Example 2

[0161] This comparative example is basically the same as Example 1, with the only difference being that in this comparative example, the PA66 fiber yarn is replaced with a low-melting-point polyester (LPET) fiber yarn (melting point: 195°C), and the heating softening temperature is changed to 190°C.

[0162] Comparative Example 3

[0163] This comparative example is substantially the same as Example 1, except that the weaving density of the PA66 fiber filaments in this comparative example is the same as the weaving density of the E-type alkali-free glass fiber filaments.

[0164] Comparative Example 4

[0165] This comparative example is basically the same as Example 1, except that the content of PA66 and PP in this comparative example is 40% (the surface effect diagram of the laminate obtained in this example is shown in FIG. Fig. 9 shown).

[0166] Comparative Example 5

[0167] This comparative example is basically the same as Example 1, except that PA66 fiber yarn is not used in this comparative example (the woven cloth is woven from E-type alkali-free glass fiber yarn, and the gram weight is controlled to be 500g / m 2 ) (The surface effect diagram of the laminate obtained in this embodiment is as follows Fig.10 shown).

[0168] Test example:

[0169] Strips were cut from the laminates obtained from the examples and comparative examples (the laminated composite sheets without steel plates at the edges of the laminates in Example 8) and tested for tensile strength (strip size: 1A dumbbell shape), bending strength (strip size: 127mm*12.7mm*3.2mm), and compressive strength (strip size: 140mm*12mm*4mm). The test results are shown in Table 1.

[0170] Tensile strength test standard: GB / T1040-2006

[0171] Flexural strength test standard: ASTM D790

[0172] Compression strength test standard: ASTM D6641

[0173] Table 1 Test results of tensile strength, flexural strength and compressive strength

[0174]

[0175]

[0176] As can be seen from Table 1, compared with Comparative Example 1, the tensile strength, bending strength and compressive strength of the laminate of the embodiment are all improved, which is because the composite sheet in the embodiment uses two different thermoplastic resins. Compared with Comparative Example 2, the tensile strength, bending strength and compressive strength of the laminate of Example 1 are better, and the laminate molding effect in the embodiment is better and the molding success rate is higher. It can be seen that by controlling the temperature difference between the first thermoplastic resin and the second thermoplastic resin, the strength and toughness of the composite sheet can be improved, and the molding effect and molding rate of the laminate can be improved. Compared with Comparative Example 3, the tensile strength, bending strength and compressive strength of the laminates of Examples 1, 4 and 5 are all improved, that is, the toughness of the laminate is increased, which is due to the increase in the weaving density of the PA66 fiber filaments, which speeds up the infiltration speed of polypropylene, thereby improving the infiltration effect, and then improving the strength and toughness of the composite sheet and the molding effect of the laminate. Compared with Comparative Example 4, the forming effects of the laminates of Example 1, Example 6 and Example 7 are better, which shows that the forming effect of the laminate can be controlled by controlling the content of the first thermoplastic resin and the second thermoplastic resin. Compared with Comparative Example 5, the tensile strength, bending strength, compressive strength and forming effect of the laminate of the embodiment are improved because the composite sheet in the embodiment uses two different thermoplastic resins.

[0177] See also Figure 8-10 , Figure 8 The composite sheet obtained in Example 1, Fig. 9 The composite sheet obtained in Comparative Example 4 is Fig.10 The composite sheet obtained in Comparative Example 5 shows that the composite sheet obtained in Example 1 is fully impregnated, has a smooth surface, and has a good molding effect. The composite sheets obtained in Comparative Examples 4 and 5 have obvious resin deficiency and fiber leakage, and have a poor molding effect.

[0178] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A composite sheet, characterized in that: The invention comprises a mixed fiber woven cloth and a first thermoplastic resin attached to the mixed fiber woven cloth; The material of the mixed fiber woven cloth includes a second thermoplastic resin and reinforcing fibers, the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1<T2.

2. The composite sheet according to claim 1, characterized in that: The melting point T1 of the first thermoplastic resin and the melting point T2 of the second thermoplastic resin satisfy: T2-T1≥30°C.

3. The composite sheet according to claim 1, characterized in that: The mixed fiber woven cloth comprises resin fiber filaments and reinforcing fiber filaments; The material of the resin fiber filaments includes the second thermoplastic resin, and the material of the reinforcing fiber filaments includes the reinforcing fibers.

4. The composite sheet according to claim 1, characterized in that: The mixed fiber woven cloth comprises mixed fiber filaments; Wherein, the material of the mixed fiber filaments includes the second thermoplastic resin and the reinforcing fiber.

5. The composite sheet according to claim 3, characterized in that: The mixed fiber woven cloth comprises first fiber filaments and second fiber filaments arranged crosswise, the first fiber filaments comprise the resin fiber filaments, and the second fiber filaments comprise the reinforcing fiber filaments, or The mixed fiber woven cloth comprises first fiber filaments and second fiber filaments arranged crosswise, the first fiber filaments comprise the resin fiber filaments and the reinforcing fiber filaments, and the second fiber filaments comprise the reinforcing fiber filaments; or The mixed fiber woven cloth includes first fiber filaments and second fiber filaments that are cross-arranged, and both the first fiber filaments and the second fiber filaments include the resin fiber filaments and the reinforcing fiber filaments.

6. The composite sheet according to claim 3, characterized in that: The diameter of the reinforcing fiber is 5 to 30 μm; and / or The ratio of the diameter of the resin fiber filament to the diameter of the reinforcing fiber filament is (1-2):

1.

7. The composite sheet according to claim 3, characterized in that: The weaving density of the resin fiber filaments in the mixed fiber woven cloth is greater than the weaving density of the reinforcing fiber filaments; and / or The total content of the first thermoplastic resin and the second thermoplastic resin in the composite sheet is 50% or more.

8. The composite sheet according to claim 3, characterized in that: The thickness of the composite sheet is ≥ 0.1 mm; and / or The weight of the mixed fiber woven cloth is 250-300 g / m 2 .

9. The composite sheet according to claim 1, characterized in that: The reinforcing fibers include one or more of glass fibers, carbon fibers, Kevlar fibers, metal fibers, and natural fibers; and / or The first thermoplastic resin and the second thermoplastic resin independently include one or more of polyethylene, polypropylene, nylon 6, nylon 66, polycarbonate, polyethylene terephthalate, polyetheretherketone, polystyrene, polybutylene terephthalate, polyester, polytetrafluoroethylene, low-density polyethylene, linear low-density polyethylene, polyphenylene sulfide, thermoplastic polyurethane elastomer, polyolefin elastomer and high-density polyethylene; and / or The composite sheet also includes a compatibilizer.

10. A method for preparing a composite sheet, characterized in that: The following steps are involved: Providing a second thermoplastic resin and reinforcing fiber filaments, and making the second thermoplastic resin and the reinforcing fiber filaments into a mixed fiber woven cloth; A first thermoplastic resin is provided and disposed on the mixed fiber woven cloth to obtain a composite sheet, wherein the melting point of the first thermoplastic resin is T1, the melting point of the second thermoplastic resin is T2, and T1<T2.

11. The method for preparing a composite sheet according to claim 10, characterized in that: The step of preparing a mixed fiber woven cloth from the second thermoplastic resin and the reinforcing fiber yarns comprises: The second thermoplastic resin is made into resin fiber filaments, and the resin fiber filaments and the reinforcing fiber filaments are woven into a mixed fiber woven cloth; or The reinforcing fiber yarn is impregnated in the second thermoplastic resin to obtain a mixed fiber yarn; or the second thermoplastic resin is made into a resin fiber yarn, and the reinforcing fiber yarn is wrapped with the resin fiber yarn to obtain a mixed fiber yarn; and the mixed fiber yarn is woven into a mixed fiber woven cloth.

12. The method for preparing a composite sheet according to claim 10, characterized in that: The providing of a first thermoplastic resin and placing the first thermoplastic resin on the mixed fiber woven cloth comprises: A first thermoplastic resin and a compatibilizer are provided and mixed, and the mixed first thermoplastic resin and the compatibilizer are arranged on the mixed fiber woven cloth.

13. The method for preparing a composite sheet according to claim 12, characterized in that: The first thermoplastic resin is disposed on the mixed fiber woven cloth to obtain a composite sheet, comprising: The first thermoplastic resin is heated to a molten state, the mixed fiber woven fabric is immersed in the molten first thermoplastic resin, and then taken out and solidified to obtain a composite sheet; or The first thermoplastic resin is made into a film, and the film is laminated and pressed with the mixed fiber woven cloth to obtain a composite sheet.

14. A laminated board, characterized in that: The invention comprises a composite sheet material as described in any one of claims 1 to 9, or a composite sheet material prepared by the method for preparing a composite sheet material as described in any one of claims 10 to 13.

15. A method for preparing a laminate, characterized in that: The following steps are involved: Provide a metal plate and at least one layer of a composite sheet as described in any one of claims 1 to 9 or a composite sheet made by the method for preparing a composite sheet as described in any one of claims 10 to 13, or provide multiple layers of a composite sheet as described in any one of claims 1 to 9 or a composite sheet made by the method for preparing a composite sheet as described in any one of claims 10 to 13, stack them, heat to soften them, and press them to obtain a laminate.

16. The method for preparing a laminate according to claim 15, characterized in that: The heating softening temperature T satisfies: T1 <T<T2。 17. A vehicle, characterized in that: It includes a composite sheet as described in any one of claims 1 to 9, or a composite sheet made by the method for preparing a composite sheet as described in any one of claims 10 to 13, or a laminate as described in claim 14, or a laminate made by the method for preparing a laminate as described in any one of claims 15 or 16.

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