Preparation method and device of continuous fiber reinforced thermoplastic resin composite material

Abstract

The invention relates to a preparation method and device of a continuous fiber reinforced thermoplastic resin composite material, and the preparation method comprises the following steps: carrying out dipping treatment on continuous fibers in a resin solution to obtain dipped fibers; carrying out extrusion treatment on the impregnated fibers to obtain impregnated and glue-pressed fibers; and carrying out drying treatment on the fibers subjected to impregnation and adhesive pressing, so as to prepare the continuous fiber reinforced thermoplastic resin composite material. According to the preparation method of the continuous fiber reinforced thermoplastic resin composite material provided by the embodiment of the invention, the continuous fiber reinforced thermoplastic resin composite material with high fiber content and better mechanical properties can be prepared.

Description

Technical Field

[0001] The present invention relates to polymer composites, and in particular to a preparation method and device for a continuous fiber reinforced thermoplastic resin composite material. Background Art

[0002] In recent years, continuous fiber reinforced thermoplastic composites (CFRTP) have been rapidly developed as a kind of high-performance composites. It uses continuous fibers as the reinforcement and thermoplastic resins as the matrix, and uses the process of thermoplastic resin melt impregnating fibers to prepare composites with high strength, high rigidity and high toughness. Continuous fibers include reinforcing materials such as continuous glass fibers, carbon fibers, aramid fibers and basalt fibers, and thermoplastic resins mainly include thermoplastic resins such as PP (polypropylene), PE (polyethylene), PA6 (polyamide 6), PET (polyethylene terephthalate). Compared with traditional thermosetting composites, CFRTP has the advantages of easy molding, light weight, high strength and toughness, recyclability, excellent heat resistance, creep resistance and dimensional stability, and can meet the requirements of various practical applications for material properties, and has broad application prospects in the fields of automobile industry, construction, aerospace, military and so on.

[0003] At present, the preparation process of continuous fiber reinforced thermoplastic composite prepreg in China basically adopts the method of thermoplastic resin melt impregnating fibers. The impregnation method used is resin melt coating impregnation. This impregnation method is simple and easy to clean. However, for thermoplastic resins with high melting temperatures and high processing viscosities such as PEI (polyetherimide), PPS (polyphenylene sulfide), PES (polyethersulfone resin), PSF (polysulfone), PEEK (polyetheretherketone resin), high-temperature PA (polyamide), it is very difficult to obtain prepreg with uniform resin dispersion and sufficient impregnation by this method. Due to the high viscosity of the molten resin, its fluidity and permeability are poor, and the fibers are difficult to be fully impregnated, and dry yarns are easily generated, resulting in low fiber content and poor mechanical properties of continuous fiber reinforced composites, thus limiting the application of matrix resins in continuous fiber reinforced composites. Summary of the Invention

[0004] To overcome at least one defect of the above-mentioned prior art, in a first aspect, an embodiment of the present invention provides a preparation method for a continuous fiber reinforced thermoplastic resin composite material, including the following steps:

[0005] Impregnate continuous fibers in a resin solution to obtain impregnated fibers;

[0006] Extrude the impregnated fibers to obtain impregnated and pressure-compacted fibers; and

[0007] Dry the impregnated and pressure-compacted fibers to obtain a continuous fiber reinforced thermoplastic resin composite material.

[0008] In a second aspect, an embodiment of the present invention provides a continuous fiber reinforced thermoplastic resin composite material, which is prepared by the above preparation method.

[0009] In a third aspect, an embodiment of the present invention provides a preparation device for a continuous fiber reinforced thermoplastic resin composite material, including a traction unit, a solution impregnation unit, a pressing unit and a drying unit; the traction unit includes a continuous fiber introduction end and a composite material extraction end which are oppositely arranged; under the action of the continuous fiber introduction end, the continuous fiber can sequentially pass through the impregnation unit for impregnation treatment, pass through the pressing unit for extrusion treatment, and pass through the drying unit for drying treatment.

[0010] In a fourth aspect, an embodiment of the present invention provides an application of the above continuous fiber reinforced thermoplastic resin composite material in the preparation of pultruded products.

[0011] The preparation method of the continuous fiber reinforced thermoplastic resin composite material according to an embodiment of the present invention can prepare a continuous fiber reinforced thermoplastic resin composite material with a high fiber content and excellent material mechanical properties. Description of the Drawings

[0012] The drawings are only for the purpose of showing specific embodiments, and are not considered as a limitation to the present invention. Among them:

[0013] Figure 1 is a schematic structural diagram of a preparation device for a continuous fiber reinforced thermoplastic resin composite material according to an embodiment of the present invention;

[0014] Figure 2 is a schematic structural diagram of a traction unit, a solution impregnation unit, a pressing unit and a drying unit according to an embodiment of the present invention;

[0015] Figure 3 is a schematic structural diagram of a preparation device for a continuous fiber reinforced thermoplastic resin composite material according to another embodiment of the present invention;

[0016] Figure 4 is a schematic structural diagram of a traction unit, a solution impregnation unit, a pressing unit, a drying unit and a solution recovery unit according to an embodiment of the present invention;

[0017] The description of the reference numerals in the drawings is as follows:

[0018] 001. Continuous fiber inlet end; 002. Composite material outlet end; 003. Input guide roller; 004. Output guide roller; 100. Solution impregnation unit; 200. Pressing unit; 300. Drying unit; 400. Solution recovery unit; 101. Impregnation tank; 102. Yarn spreading roller; 201. Upper pressing roller; 202. Lower pressing roller; 301. Drying oven; 302. Guide wheel; 303. Solvent recovery tank; 304. Vacuum pump; 401. Glue receiving tank. Detailed implementation mode

[0019] Typical implementation modes reflecting the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different implementation modes, all of which do not depart from the scope of the present invention, and the descriptions therein are for illustrative purposes in essence rather than to limit the present invention. The same components are denoted by the same reference numerals. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings. The terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0020] Refer to Figure 1 As shown, an implementation mode of the present invention provides a preparation device for continuous fiber reinforced thermoplastic resin composite materials, including a traction unit, a solution impregnation unit 100, a pressing unit 200 and a drying unit 300; wherein, the traction unit includes a relatively arranged continuous fiber inlet end 001 and a composite material outlet end 002; the continuous fiber sequentially passes through the solution impregnation unit 100, the pressing unit 200, the drying unit 300 and the composite material outlet end 002 from the continuous fiber inlet end 001.

[0021] In one implementation mode, the traction unit is used to traction the continuous fiber to move between the continuous fiber inlet end 001 and the composite material outlet end 002, and make the continuous fiber pass through the solution impregnation unit 100, the pressing unit 200 and the drying unit 300 in sequence.

[0022] In one implementation mode, the continuous fiber enters the solution impregnation unit 100 from the continuous fiber inlet end 001, and the solution impregnation unit 100 is used to impregnate the continuous fiber with a solution to obtain continuous fiber attached with the solution (or impregnated fiber). Wherein, the above solution is a resin solution.

[0023] In one implementation mode, a resin solution can be set in the solution impregnation unit 100 for solution impregnation. The resin solution includes a thermoplastic resin (such as polyamide) and a solvent; further, the resin solution can also include other raw materials, such as additives, and the additives include one or more of auxiliaries such as flame retardants, nucleating agents, and reinforcing agents.

[0024] In one embodiment, the pressing unit 200 is used to squeeze the impregnated fibers, so that the solution is evenly attached to the continuous fibers, and the excess resin solution is removed to obtain the fibers after impregnation and pressing.

[0025] In one embodiment, the drying unit 300 is used to dry the fibers after impregnation and pressing, so as to form a continuous fiber reinforced thermoplastic resin composite integrated structure with the continuous fibers and the solution (fibers after impregnation and pressing), and the formed composite material is output from the lead-out end 002.

[0026] In one embodiment, the above-mentioned preparation device for continuous fiber reinforced thermoplastic resin composite is used to prepare continuous fiber reinforced thermoplastic composite by solution impregnation method; specifically, a thermoplastic resin and a solvent are formulated into a resin solution with a certain concentration. When the continuous fibers pass through the solution impregnation unit 100, the thermoplastic resin is evenly attached to the continuous fibers, and then the excess resin solution is removed by the pressing unit 200, and the solvent is removed by the drying unit 300, so as to obtain a composite material with resin evenly distributed on the continuous fibers. The use of this device or method is of great significance for reducing the resin viscosity in the impregnation process, increasing the glass fiber content of the composite material, and improving the mechanical properties of the composite material.

[0027] In one embodiment, referring to Figure 2 As shown, the solution impregnation unit 100 includes an impregnation tank 101 and a yarn spreading roller 102.

[0028] In one embodiment, the solution impregnation unit 100 includes an impregnation tank 101 and at least one yarn spreading roller 102 disposed in the impregnation tank 101. The yarn spreading roller 102 is used to apply tension to the continuous fibers, which can produce a tensioning effect on the continuous fibers to prevent the continuous fibers from agglomerating in the resin solution. A heat circulation structure can be arranged in the impregnation tank 101 to control the temperature of the solution in the impregnation unit, so that the continuous fibers can obtain a better impregnation effect.

[0029] In one embodiment, the yarn spreading roller 102 is detachably connected in the impregnation tank 101. During the operation process, the yarn spreading roller 102 is located in the impregnation solution.

[0030] In one embodiment, the number of the yarn spreading rollers 102 is multiple. The multiple yarn spreading rollers 102 are arranged staggeredly (or offset) along the moving direction of the continuous fibers in the impregnation tank 101. There is a certain gap between adjacent yarn spreading rollers 102 for adjustment during production. Preferably, the multiple yarn spreading rollers 102 are divided into two rows, an upper yarn spreading roller located relatively above and a lower yarn spreading roller located relatively below. The upper yarn spreading roller and the lower yarn spreading roller are staggeredly distributed. During operation, the continuous fibers sequentially bypass above the upper yarn spreading roller and below the lower yarn spreading roller.

[0031] In one embodiment, the thermal cycling structure includes, but is not limited to, a hydrothermal cycling structure. For example, a circulating water pipe is installed on the impregnation tank 101, and water is used as a medium to heat or cool the resin solution.

[0032] In one embodiment, a temperature display structure is provided inside the impregnation tank 101. The temperature display structure can obtain the temperature of the resin solution inside the impregnation tank 101 in real time. The temperature display structure is used in conjunction with the thermal cycling structure to keep the resin solution inside the impregnation tank 101 within a suitable temperature range.

[0033] In one embodiment, a stirring structure is provided inside the impregnation tank 101. The stirring structure can keep the concentration of the resin solution inside the impregnation tank 101 uniform, so as to obtain a better impregnation effect for continuous fibers.

[0034] In one embodiment, a yarn guiding structure is provided inside the impregnation tank 101. The yarn guiding structure and the yarn spreading roller 102 are both connected to the inner wall of the impregnation tank 101, and are used to adjust the height of the yarn spreading roller 102.

[0035] In one embodiment, a vibration structure is provided on the yarn spreading roller 102. The vibration structure can enhance the vibration amplitude and frequency of the yarn spreading roller 102, thereby further improving the yarn spreading effect.

[0036] In one embodiment, the material of the yarn spreading roller 102 includes one or more of 316 stainless steel, 316L stainless steel, 2205 stainless steel, and Hastelloy, and preferably 316L stainless steel.

[0037] In one embodiment, the impregnation tank 101 includes a box body and a sealing cover that is detachably connected to the box body. The box body is used to hold the resin solution, and the sealing cover is detachably connected to the box body to open and close the box body. When the sealing cover is opened, it is convenient for workers to operate, such as replenishing the resin solution. When the sealing cover is closed, it can effectively prevent the smell of the resin solution from spreading to the outside, prevent impurities in the air from entering the resin solution, avoid contamination, and prevent the solvent in the resin solution from volatilizing too quickly, resulting in an increase in the viscosity of the resin solution and affecting the impregnation effect of continuous fibers.

[0038] In one embodiment, a sealing cover for overall sealing the box opening is provided on the box body of the impregnation tank 101. The sealing cover can be partially opened, or a through hole for guiding continuous fibers in and out is provided on the sealing cover, so that continuous fibers can enter and exit the impregnation tank 101.

[0039] In another embodiment, two through holes for guiding continuous fibers in and out are provided on the box body of the impregnation tank 101, and the sealing cover is used to seal the through holes.

[0040] In one embodiment, at least one guide roller is arranged on the box body along the moving direction of the continuous fiber. There is a certain gap between adjacent guide rollers for adjustment during production. The guide roller is used to guide the movement of the continuous fiber in the impregnation tank 101 so that the continuous fiber can effectively pass through the impregnation tank 101 to achieve sufficient impregnation.

[0041] In one embodiment, the number of guide rollers is multiple, and the multiple guide rollers are arranged staggeredly along the moving direction of the continuous fiber inside (i.e., the periphery of) the impregnation tank 101. There is a certain gap between adjacent guide rollers for adjustment during production.

[0042] In one embodiment, referring to Figure 4 As shown, the number of guide rollers is two, namely the input guide roller 003 and the output guide roller 004. The input guide roller 003 and the output guide roller 004 are respectively arranged at opposite ends of the impregnation tank 101 along the moving direction of the continuous fiber. The input guide roller 003 is used to introduce the continuous fiber into the impregnation tank 101, and the output guide roller 004 is used to draw out the impregnated fiber from the impregnation tank 101.

[0043] In one embodiment, the material of the guide roller includes one or more of 316 stainless steel, 316L stainless steel, 2205 stainless steel, 304 stainless steel, Hastelloy, PE, PP, and PTFE, preferably 316L stainless steel or PP.

[0044] In one embodiment, the pressing unit 200 includes at least two squeezing rollers. Every two squeezing rollers are opposite and spaced apart, and are respectively arranged on opposite sides of the continuous fiber. The continuous fiber attached with the resin solution is passed between the two squeezing rollers to remove the excess resin solution on the continuous fiber, and can also be used to control the thickness of the resin solution on the continuous fiber, thereby controlling the thickness of the continuous fiber reinforced thermoplastic resin composite material.

[0045] Referring to Figure 2 、 4 As shown, in one embodiment, the number of squeezing rollers can be adjusted according to the length of the continuous fiber. The longer the length of the continuous fiber, the more the number of squeezing rollers, and there are at least two. Every two squeezing rollers form a group and are respectively located on opposite sides of the continuous fiber. The squeezing roller located above the continuous fiber is the upper squeezing roller 201, and the squeezing roller located below the continuous fiber is the lower squeezing roller 202. There is a certain distance between the upper squeezing roller 201 and the lower squeezing roller 202, and this distance can be 0.1 - 2 mm.

[0046] In one embodiment, the material of the squeezing roller includes one or more of 316 stainless steel, 316L stainless steel, 2205 stainless steel, 304 stainless steel, Hastelloy, PE, PP, and PTFE, preferably 316L stainless steel or PP.

[0047] In one embodiment, grooves and protrusions that can mesh with each other are respectively provided on the extrusion rollers arranged opposite to each other in pairs. Both the grooves and the protrusions extend along the axial direction of the extrusion rollers. The impregnated fibers pass through the extrusion rollers with grooves and protrusions, further playing the role of separating and equalizing the yarns, preventing the phenomenon of stacking of the impregnated fibers, and avoiding uneven quality of subsequent products.

[0048] In one embodiment, grooves and protrusions that mesh with each other are respectively arranged along the axial direction on the surfaces of the upper extrusion roller 201 and the lower extrusion roller 202.

[0049] In one embodiment, the drying unit 300 includes a drying box 301 and a heating structure. A solvent recovery tank 303 and a vacuum pump 304 are provided on the drying box 301. Among them, the heating structure can adjust the temperature in the drying box 301, and the vacuum pump 304 is used to keep the drying box 301 in a relatively vacuum environment, so that the heating process of the continuous fibers by the drying unit 300 is carried out under vacuum conditions, thereby improving the heat treatment quality; the solvent recovery tank 303 can be arranged at the top or the upper middle part of the drying box 301. During the drying process, solvents will volatilize, and the volatilized solvents are recovered through the solvent recovery tank 303 for subsequent use.

[0050] In one embodiment, the heating structure is arranged in the drying box 301. The heating structure includes one or more of an oil bath heating structure, an infrared heating structure, and an electric heating structure. For example, the heating structure adopts an oil bath heating structure, that is, a plurality of uniformly distributed metal conduits are arranged in the drying box 301, and the metal conduits are heated by circulating heat-conducting oil, and the fibers after impregnation and pressure bonding are dried by means of heat convection. Drying with an oil bath heating structure has uniform heating and good drying effect.

[0051] In one embodiment, at least one guide wheel 302 is arranged in the drying box 301, and the continuous fiber passes through the guide wheel 302. The guide wheel 302 is used to guide the direction of the continuous fiber. By adding the guide wheel 302, the moving distance of the continuous fiber in the drying box 301 can be extended, the drying time is increased, and thus the drying rate is improved.

[0052] In one embodiment, the number of the guide wheels 302 is multiple, and the multiple guide wheels 302 are staggered along the moving direction of the continuous fiber in the drying box 301, and there is a certain gap between adjacent guide wheels 302 for adjustment during production. The fibers after impregnation and pressure bonding pass through the guide wheels 302 in sequence and are reciprocally pulled in the drying box 301, increasing the drying time.

[0053] In one embodiment, a ceramic layer or a self-lubricating layer is provided on at least the surface of the guide roller 302. The friction of the ceramic or self-lubricating material is small. When the fiber after impregnating and pressing contacts the ceramic layer or the self-lubricating layer of the guide roller 302, the friction in the drying device can be reduced. Other coatings with a friction equivalent to that of the ceramic layer can also be provided on the surface of the guide roller 302.

[0054] In one embodiment, the material of the guide roller 302 includes one or more of 316 stainless steel, 316L stainless steel, 2205 stainless steel, 304 stainless steel, Hastelloy, PE, PP, and PTFE, and it can also be made of ceramic or self-lubricating material.

[0055] In one embodiment, referring to Figure 3 As shown, the preparation device for the continuous fiber reinforced thermoplastic resin composite includes a traction unit, a solution impregnation unit 100, a pressing unit 200, a drying unit 300 solution, and a recovery unit 400.

[0056] In one embodiment, the solution recovery unit 400 is disposed opposite to the pressing unit 200, that is, the solution recovery unit 400 is located directly below the pressing unit 200. The solution recovery unit 400 can receive the excess resin solution extruded from the continuous fiber by the pressing unit 200 for reuse.

[0057] In one embodiment, the two opposite ends of the solution recovery unit 400 are respectively communicated with the solution impregnation unit 100 and the drying unit 300, that is, the solution recovery unit 400 is located between the drying box 301 and the impregnation box 101. One end of it is communicated with the drying box 301, and the other end is communicated with the impregnation box 101. A solvent recovery tank 303 is provided on the drying box 301 to recover the volatilized resin solution in the drying box 301 and transport it to the solution recovery unit 400. All the collected resin solutions can be transported to the impregnation box 101 through the solution recovery unit 400 for recycling.

[0058] In one embodiment, referring to Figure 4 As shown, the solution recovery unit 400 includes a glue receiving groove 401.

[0059] In one embodiment, the glue receiving groove 401 is obliquely disposed between the drying box 301 and the impregnation box 101 and is located directly below the pressing unit 200 (for example, directly below). The two ends of the glue receiving groove 401 are respectively connected to the drying box 301 and the impregnation box 101. The end connected to the drying box 301 is higher than the end connected to the impregnation box 101, so that the resin solution in the glue receiving groove 401 can enter the impregnation box 101 by its own weight.

[0060] In one embodiment, the glue receiving groove 401 is an opening with an inclined surface. The opening of the glue receiving groove 401 is connected to the impregnation tank 101 without a gap. The resin solution extruded by the upper extrusion roller 201 and the lower extrusion roller 202 can flow into the glue receiving groove 401 along the inclined surface of the opening of the glue receiving groove 401, and finally return to the impregnation tank 101 for recovery.

[0061] For the preparation device of the continuous fiber reinforced thermoplastic resin composite material according to one embodiment of the present invention, during operation, continuous fibers enter the solution impregnation unit 100 through the continuous fiber introduction end 001, and enter the impregnation tank 101 through the input guide roller 003. After solution impregnation in the impregnation tank 101, the impregnated fibers are obtained, and the impregnated fibers are led out of the impregnation tank 101 through the output guide roller 004; then, the impregnated fibers are extruded by the upper extrusion roller 201 and the lower extrusion roller 202 to obtain the impregnated and pressure-compacted fibers; afterwards, the impregnated and pressure-compacted fibers are introduced into the drying oven 301 for vacuum heating and drying, and finally enter the composite material lead-out end 002 under the traction of the guide wheel 302 to obtain the continuous fiber reinforced thermoplastic resin prepreg yarn.

[0062] One embodiment of the present invention provides a method for preparing a continuous fiber reinforced thermoplastic resin composite material, including the following steps:

[0063] Impregnate the continuous fibers in a resin solution to obtain impregnated fibers;

[0064] Extrude the impregnated fibers to obtain impregnated and pressure-compacted fibers; and

[0065] Dry the impregnated and pressure-compacted fibers to prepare the continuous fiber reinforced thermoplastic resin composite material.

[0066] The method for preparing a continuous fiber reinforced thermoplastic resin composite material according to one embodiment of the present invention can be implemented using the above-mentioned preparation device. Further, the impregnation treatment can be carried out in the solution impregnation unit 100, the extrusion treatment can be carried out in the pressure application unit 200, and the drying treatment can be carried out in the drying unit 300.

[0067] In one embodiment, the resin solution for impregnating the continuous fibers includes a polyamide resin. The mass content of the polyamide resin in the resin solution can be 3 to 25 wt%, further can be 8 to 15 wt%, such as 4 wt%, 5 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 18 wt%, 20 wt%, 21 wt%, 22 wt%.

[0068] In one embodiment, the resin solution includes a polyamide resin and optional additives, and the additives can be one or more of a flame retardant, a nucleating agent, and a reinforcing agent.

[0069] In one embodiment, the preparation monomers of the polyamide resin contained in the resin solution include a diamine and a dicarboxylic acid. The diamine can be an aliphatic diamine containing 4 to 6 carbon atoms, and the dicarboxylic acid can include one or more of an aliphatic dicarboxylic acid containing 6 to 8 carbon atoms and an aromatic dicarboxylic acid containing 8 to 10 carbon atoms.

[0070] In one embodiment, the diamine used to prepare the polyamide resin can be pentamethylenediamine.

[0071] In one embodiment, the aromatic dicarboxylic acid used to prepare the polyamide resin can be one or more of terephthalic acid, phthalic acid, and isophthalic acid.

[0072] In one embodiment, the polyamide resin can be one or more of PA56T resin, PA56 resin, PA56TI resin, and PA5T66 resin. Among them, PA56T resin is obtained by copolymerizing the monomers pentamethylenediamine, adipic acid, and terephthalic acid; PA56 resin is obtained by copolymerizing the monomers pentamethylenediamine and adipic acid; PA56TI resin is obtained by copolymerizing the monomers pentamethylenediamine, adipic acid, terephthalic acid, and isophthalic acid; PA5T66 resin is obtained by copolymerizing the monomers pentamethylenediamine, hexamethylenediamine, terephthalic acid, and adipic acid.

[0073] In one embodiment, the relative viscosity of the polyamide resin can be 2.0 to 2.6, further can be 2.2 to 2.5, such as 2.2, 2.3, 2.4, 2.5.

[0074] In one embodiment, the melting point of the polyamide resin can be 200 to 300 °C, further can be 250 to 270 °C, such as 210 °C, 230 °C, 255 °C, 258 °C, 260 °C, 262 °C, 265 °C, 268 °C, 290 °C, 295 °C, 297 °C.

[0075] In one embodiment, during the preparation process of the continuous fiber reinforced thermoplastic resin composite, the temperature of the impregnation tank 101 of the solution impregnation unit 100 or the temperature for solution impregnation treatment of the continuous fiber can be 18 to 45 °C, further can be 35 to 40 °C, such as 20 °C, 25 °C, 30 °C, 36 °C, 37 °C, 38 °C. Keeping the impregnation treatment temperature within the above range can keep the resin solution in good uniformity, and further make the impregnation of the fiber more uniform.

[0076] In one embodiment, during the preparation of the continuous fiber reinforced thermoplastic resin composite material, through the traction action of the traction unit, the continuous fiber sequentially undergoes impregnation treatment, extrusion treatment, and drying treatment; the traction speed of the traction unit is 2 to 150 m / min, further it can be 2 to 120 m / min, such as 4 m / min, 9 m / min, 10 m / min, 11 m / min, 15 m / min, 19 m / min, 20 m / min, 21 m / min, 25 m / min, 29 m / min, 30 m / min, 31 m / min, 35 m / min, 39 m / min, 40 m / min, 41 m / min, 44 m / min, 45 m / min, 46 m / min, 80 m / min, 85 m / min, 90 m / min, 110 m / min, 115 m / min, 120 m / min, 130 m / min, 140 m / min.

[0077] In one embodiment, during the preparation of the continuous fiber reinforced thermoplastic resin composite material, the temperature of the drying unit 300 or the temperature for drying the fiber after impregnation and pressing can be 170 to 225 °C, such as 175 °C, 185 °C, 195 °C, 205 °C, 215 °C, 220 °C.

[0078] In one embodiment, the continuous fiber reinforced thermoplastic resin composite material can be a continuous fiber reinforced thermoplastic resin prepreg yarn.

[0079] In one embodiment, the continuous fiber for impregnation treatment with a resin solution can be glass fiber.

[0080] In one embodiment, the continuous fiber used for preparing the continuous fiber reinforced thermoplastic resin composite material is glass fiber, and the mass content of glass fiber in the composite material can be 70 to 97%, further it can be 80 to 90%, such as 72%, 73%, 75%, 79%, 82%, 84%, 85%, 86%, 87%, 88%, 91%, 93%, 94%, 95%.

[0081] In one embodiment, the flexural modulus of the continuous fiber reinforced thermoplastic resin composite material can be 40 to 65 GPa, such as 43 GPa, 44 GPa, 45 GPa, 46 GPa, 50 GPa, 53 GPa, 54 GPa, 55 GPa, 56 GPa, 57 GPa, 58 GPa, 60 GPa, 61 GPa, 62 GPa, 63 GPa.

[0082] In one embodiment, the flexural strength of the continuous fiber reinforced thermoplastic resin composite material can be 880 - 1330 MPa, such as 880 MPa, 886 MPa, 890 MPa, 900 MPa, 950 MPa, 952 MPa, 953 MPa, 956 MPa, 957 MPa, 1000 MPa, 1020 MPa, 1021 MPa, 1022 MPa, 1030 MPa, 1063 MPa, 1064 MPa, 1100 MPa, 1200 MPa, 1262 MPa, 1263 MPa, 1270 MPa, 1287 MPa, 1288 MPa, 1300 MPa, 1310 MPa, 1313 MPa, 1314 MPa, 1327 MPa, 1328 MPa.

[0083] In one embodiment, the deviation of the glass fiber content in the continuous fiber reinforced thermoplastic resin composite material is less than 2.5 wt%, and further can be less than 2 wt%.

[0084] In one embodiment, the flexural modulus of the continuous fiber reinforced thermoplastic resin composite material is above 40 GPa, and further can be above 50 GPa.

[0085] In one embodiment, the flexural strength of the continuous fiber reinforced thermoplastic resin composite material is above 880 MPa, and further can be above 1000 MPa.

[0086] One embodiment of the present invention provides the application of the above-mentioned continuous fiber reinforced thermoplastic resin composite material in the preparation of pultruded products.

[0087] In one embodiment, a formed pultruded product is obtained by subjecting the raw material to pultrusion molding treatment, and the raw material includes the above-mentioned continuous fiber reinforced thermoplastic resin composite material. Further, the pultruded product can be a hollow or profiled product.

[0088] In one embodiment, the pultrusion molding process (or pultrusion process) can be an existing process. For example, it can be to form and cure a pre-impregnated yarn by passing it through an extrusion die under the action of traction force.

[0089] In the prior art, continuous fiber reinforced thermoplastic composites are prepared by melt impregnation. Due to the high melting temperature and high viscosity of thermoplastic resins, the continuous fiber reinforced composites obtained usually have a low fiber content and poor mechanical properties. An embodiment of the present invention provides a device / method for preparing a continuous fiber reinforced thermoplastic resin composite. By means of solution impregnation (or a solution impregnation unit), continuous fiber reinforced thermoplastic composites are prepared, enabling the thermoplastic resin to uniformly adhere to the continuous fibers. Then, through a pressing unit (or extrusion treatment), the excess resin solution is removed, and a drying unit (or drying treatment) removes the solvent, thereby obtaining a composite material with the resin uniformly distributed on the continuous fibers. Moreover, it is of great significance for reducing the resin viscosity during the impregnation process, increasing the glass fiber content of the composite material, and improving the mechanical properties of the composite material.

[0090] Hereinafter, with reference to the accompanying drawings and specific embodiments, the preparation of a continuous fiber reinforced thermoplastic composite (continuous glass fiber / thermoplastic polyamide resin prepreg) according to an embodiment of the present invention will be further described. Among them, each embodiment uses Figure 4 the shown preparation device to prepare continuous glass fiber / thermoplastic polyamide resin prepreg; the continuous fibers used in each embodiment and comparative example are continuous glass fibers with a linear density of 1200 tex. The test methods involved in each embodiment and comparative example are as follows:

[0091] Testing method

[0092] 1. Bending property test

[0093] The complete performance is tested according to the test method for the bending properties of fiber-reinforced plastics in GB / T 1449-2005. Among them, according to this method, an impregnated yarn plate specimen is prepared. In the three-point bending test, the specifications of the specimen are 80 mm × 10 mm × 4 mm (length × width × thickness), the test span is 64 mm, the specimen shows interlaminar shear failure, and specimens with obvious internal defects or failures outside the middle one-third of the specimen should be invalidated. The number of valid specimens in the same batch is not less than 5.

[0094] 2. Test of glass fiber content

[0095] The glass fiber content is tested according to the calcination method of ISO 1172: the glass fiber content is obtained by calculating the difference between the mass of the calcined sample and the mass of the dry sample. The specific process is: weigh the clean and dry crucible, and record the mass in grams as m1; place the sample in the crucible and dry it to a constant mass in a ventilated drying oven at 105°C, cool it to room temperature in a dryer and re-weigh and record the mass m2; calcine it at a constant temperature of 700°C in a muffle furnace for 120 minutes, then cool the residue and the crucible together in a dryer to room temperature and weigh its mass m3. Each group of test samples has at least two samples, the mass of the samples is in the range of 2 to 10g, and the difference between the measured values ​​is less than 5%. Use equation (1) to calculate the glass fiber content M of each sample glass .

[0096]

[0097] When testing the glass fiber content of the prepreg obtained in the embodiment or comparative example, sampling and testing are performed every 50 m from the initial winding of the prepreg, and 20 groups of samples are taken, each of which has a prepreg length of 10 ± 0.5 m. The standard deviation σ of the glass fiber content of the prepreg is calculated using equation (2), which represents the stability of the glass fiber content of the prepreg. i is the glass fiber content value of each group of samples, is the average glass fiber content of all samples, and n is the number of sampling groups.

[0098]

[0099] 3. Resin relative viscosity (ηr) test

[0100] Ubbelohde viscometer concentrated sulfuric acid method: Accurately weigh 0.5±0.0002 g of the dried polyamide resin sample, add 50 mL of concentrated sulfuric acid (96%) to dissolve it to obtain a polyamide solution, and measure and record the concentrated sulfuric acid flow time t0 and the polyamide solution flow time t in a 25°C constant temperature water bath, respectively.

[0101] Relative viscosity calculation formula:

[0102] Relative viscosity ηr = t / t0.

[0103] Example 1

[0104] (1) A certain amount of polyamide resin (PA56T resin, melting point 260° C., relative viscosity 2.35) was dissolved in 85 wt % formic acid aqueous solution and stirred thoroughly to obtain a polyamide resin solution, in which the content of polyamide was 10 wt %.

[0105] (2) Add the polyamide resin solution prepared in step (1) to the impregnation tank 101 of the solution impregnation unit 100, and set the temperature of the impregnation tank to 37°C; start to draw the continuous fiber from the introduction end 001, and successively pass through the solution impregnation unit 100, the pressure application unit 200 and the drying unit 300 for corresponding treatments, and finally output from the composite material outlet end 002 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn.

[0106] Among them, two groups of yarn spreading rollers 102 are arranged in the impregnation tank 101, and each group of yarn spreading rollers 102 consists of an upper yarn spreading roller and a lower yarn spreading roller; during the preparation process, control the height of the liquid level in the impregnation tank 101 to always exceed the yarn spreading rollers 102, the drawing speed of the traction unit for the continuous fiber (or prepreg yarn) is 10 m / min, and the drying temperature of the drying unit 300 is 180°C.

[0107] Example 1-1

[0108] This example uses basically the same raw materials and process as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, the difference is only that: the content of polyamide in the polyamide resin solution prepared in step (1) is 13 wt%.

[0109] Example 1-2

[0110] This example uses basically the same raw materials and process as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, the difference is only that: the content of polyamide in the polyamide resin solution prepared in step (1) is 15 wt%.

[0111] Example 1-3

[0112] This example uses basically the same raw materials and process as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, the difference is only that: the content of polyamide in the polyamide resin solution prepared in step (1) is 18 wt%.

[0113] Example 1-4

[0114] This example uses basically the same raw materials and process as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, the difference is only that: the content of polyamide in the polyamide resin solution prepared in step (1) is 20 wt%.

[0115] Example 1-5

[0116] This example uses basically the same raw materials and process as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, the difference is only that: the content of polyamide in the polyamide resin solution prepared in step (1) is 4 wt%.

[0117] Example 1-6

[0118] This example uses substantially the same raw materials and processes as Example 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that in step (2), the temperature of the impregnation tank is set to 18°C.

[0119] Example 2

[0120] This example uses substantially the same raw materials and processes as Example 1-1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 4 m / min.

[0121] Example 2-1

[0122] This example uses substantially the same raw materials and processes as Example 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 10 m / min.

[0123] Example 2-2

[0124] This example uses substantially the same raw materials and processes as Example 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 30 m / min.

[0125] Example 2-3

[0126] This example uses substantially the same raw materials and processes as Example 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 60 m / min.

[0127] Example 2-4

[0128] This example uses substantially the same raw materials and processes as Example 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 90 m / min.

[0129] Example 2-5

[0130] This example uses substantially the same raw materials and processes as Example 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarn, with the only difference being that during the preparation process, the traction speed of the continuous fiber (or prepreg yarn) by the traction unit is 115 m / min.

[0131] Example 2-6

[0132] This embodiment uses substantially the same raw materials and process as those of Embodiment 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarns, with the only difference being that the pulling speed of the pulling unit for the continuous fiber (or prepreg yarn) during the preparation process is 140 m / min.

[0133] Embodiment 2-7

[0134] This embodiment uses substantially the same raw materials and processes as those in Embodiment 2 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarns, with the only difference being that the pulling speed of the pulling unit for the continuous fiber (or prepreg yarn) during the preparation process is 110 m / min. The drying temperature of the drying unit 300 is 220°C.

[0135] Example 3

[0136] This embodiment uses substantially the same raw materials and processes as those of Embodiment 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarns, with the only difference being that step (1) is different and the drying temperature of the drying unit 300 is different, being 175°C.

[0137] Step (1) is: dissolving a certain mass of polyamide resin (PA56 resin, melting point of 255° C., relative viscosity of 2.5) in a 90wt% formic acid aqueous solution, and stirring thoroughly to obtain a polyamide resin solution, in which the content of polyamide is 13wt%.

[0138] Example 3-1

[0139] This embodiment uses substantially the same raw materials and processes as those of Embodiment 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarns, with the only difference being that step (1) is different and the drying temperature of the drying unit 300 is different, being 185°C.

[0140] Step (1) is: dissolving a certain mass of polyamide resin (PA56TI resin, melting point of 200° C., relative viscosity of 2.2) in a 92wt% formic acid aqueous solution, and stirring thoroughly to obtain a polyamide resin solution, in which the content of polyamide is 13wt%.

[0141] Example 3-2

[0142] This embodiment uses substantially the same raw materials and processes as those of Embodiment 1 to prepare continuous glass fiber / thermoplastic polyamide resin prepreg yarns, with the only difference being that step (1) is different and the drying temperature of the drying unit 300 is different, being 185°C.

[0143] Step (1) is: dissolving a certain mass of polyamide resin (PA5T66 resin, melting point of 297° C., relative viscosity of 2.3) in a 92wt% formic acid aqueous solution, and stirring thoroughly to obtain a polyamide resin solution, in which the content of polyamide is 13wt%.

[0144] Comparative Example 1

[0145] (1) Bisphenol A epoxy resin, curing agent dicyandiamide, and active thickener polyetheramine were mixed and stirred at a mass ratio of 10:1:1 at 40°C. The stirring speed was 150 rpm, and the stirring time was 20 min to obtain a uniform and stable mixed solution. The mixed solution was cooled to room temperature to obtain a low-temperature curing epoxy resin system;

[0146] (2) The low-temperature curing epoxy resin system prepared in step (1) was placed in the glue tank of a film coater and heated to 40°C. The viscosity of the resin system at this temperature was 16 Pa·s; Separation paper required for preparing the glue film was laid, the gap of the glue coating roller was adjusted to 0.02 mm, and the surface density of the resin glue film was 25 g / m 2 , and the film coater was started to prepare an epoxy resin glue film using the above epoxy resin system. The thickness of the glue film was detected by an infrared ray instrument, cooled, and wound to obtain a resin glue film with separation paper covered on both sides;

[0147] (3) The above glue film was led out from the upper and lower glue film rollers of a prepreg machine, and glass fiber was led out from a yarn rack. The glass fiber was located between two layers of glue film and passed through 2 - 3 groups of hot rolling rollers at 45°C on the prepreg machine in sequence to fully impregnate the resin glue film and glass fiber, and then through steps such as cooling, film covering (polyethylene film), and winding to obtain a fiber epoxy resin low-temperature curing prepreg with a glass fiber content of about 77%.

[0148] The composites prepared in each example and comparative example were tested for glass fiber content, bending properties, etc. according to the foregoing method. The results are shown in Table 1.

[0149] Table 1

[0150]

[0151]

[0152] Comparative Example 1 used a prepreg form to prepare a low-temperature curing composite material. The main problem is that since the pot life of a general low-temperature curing resin system is only a few hours, it will cure quickly after being made into a prepreg, and it cannot meet the time requirements for processes such as pre-impregnation, cutting, and laying of some components. The preparation process of the thermoplastic resin system impregnated yarn in the examples of the present invention is simple, the production is more convenient, the stability is high, and there is no difficulty in storage, which has obvious advantages in promoting the use of impregnated yarn.

[0153] As can be seen from the data in Table 1, for the continuous glass fiber / thermoplastic polyamide resin prepreg yarn (i.e., continuous fiber reinforced thermoplastic resin composite) prepared in the embodiments of the present invention, the product performance is controllable, the glass fiber content can be maintained between 72% and 97%, the deviation of the glass fiber content is maintained within 2.5%, the flexural modulus is maintained above 43 GPa, and the flexural strength is maintained above 880 MPa.

[0154] Furthermore, according to the descriptions of Examples 1 to 1-5, the difference between them lies in the content of polyamide in the polyamide resin solution used for impregnation, which are 10 wt%, 13 wt%, 15 wt%, 18 wt%, 20 wt%, and 4 wt% in sequence. As can be seen from the results in Table 1, although the glass fiber content of the composites in Examples 1-5 is relatively high, the deviation of the glass fiber content is also relatively large, indicating relatively low glass fiber stability, uneven impregnation effect, and further affecting the mechanical properties of the material. In addition, the glass fiber content of the composites in Examples 1-4 is relatively low, indicating that the content of polyamide resin in the material is relatively high; at the same time, the deviation of its glass fiber content is relatively large, indicating relatively low glass fiber stability and uneven impregnation effect.

[0155] The above results show that polyamide solutions with relatively low or high resin content will have an adverse impact on the glass fiber stability of the composite material and the flexural strength of the product. Generally speaking, the deviation of the glass fiber content of the composites in Examples 1, 1-1, and 1-2 is less than 2 wt%, the flexural modulus is above 50 GPa, and the flexural strength is above 1000 MPa. The above three parameters are all at a relatively good level. Therefore, the content of polyamide in the polyamide resin solution is preferably 8-18 wt%, and more preferably 8-15 wt%.

[0156] According to the descriptions of Examples 2 to 2-7, the difference between them lies in that the traction speed of the traction unit for the fiber during the preparation process is different, which are 4 m / min, 10 m / min, 30 m / min, 60 m / min, 90 m / min, 115 m / min, 140 m / min, and 110 m / min in sequence. As can be seen from the results in Table 1, for the composite material prepared in Example 2-6 with a traction speed of 140 m / min, although the glass fiber content is relatively high, the deviation of the glass fiber content is also relatively large, indicating relatively low glass fiber stability, and it may cause easy yarn breakage during the subsequent application of the material (such as preparing plates by pultrusion process); at the same time, the flexural strength of the material is significantly low. Therefore, during the preparation process of the continuous fiber reinforced thermoplastic resin composite, the traction speed of the traction unit is preferably 2-120 m / min.

[0157] Unless otherwise specified, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0158] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various other substitutions, changes, and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments and is only defined by the claims.

Claims

1. A method for preparing a continuous fiber reinforced thermoplastic resin composite material, comprising the following steps: Impregnating continuous fibers in a resin solution to obtain impregnated fibers; Extruding the impregnated fibers to obtain impregnated and compacted fibers; And Drying the impregnated and compacted fibers to obtain a continuous fiber reinforced thermoplastic resin composite material.

2. The preparation method according to claim 1, wherein The resin solution includes a polyamide resin; and / or, The continuous fibers include glass fibers; and / or, The temperature of the drying treatment is 170 - 225 °C; and / or, Under the traction of a traction unit, the continuous fibers sequentially pass through the impregnation treatment, the extrusion treatment, and the drying treatment, and the traction speed of the traction unit is 2 - 150 m / min; and / or, The temperature of the impregnation treatment is 18 - 45 °C.

3. The preparation method according to claim 2, wherein The mass content of the polyamide resin in the resin solution is 3 - 25 wt%, and further can be 8 - 15 wt%; and / or, The polyamide resin includes one or more of PA56T resin, PA56 resin, PA56TI resin, PA5T66 resin; or, The preparation monomers of the polyamide resin include a diamine and a dicarboxylic acid. The diamine includes an aliphatic diamine containing 4 - 6 carbon atoms, and the dicarboxylic acid includes one or more of an aliphatic dicarboxylic acid containing 6 - 8 carbon atoms and an aromatic dicarboxylic acid containing 8 - 10 carbon atoms; and / or, The relative viscosity of the polyamide resin is 2.0 - 2.6, and further can be 2.2 - 2.5; and / or, The traction speed of the traction unit is 2 - 120 m / min; and / or, The temperature of the impregnation treatment is 35 - 40 °C.

4. A continuous fiber reinforced thermoplastic resin composite material prepared by the preparation method according to any one of claims 1 to 3.

5. The composite material according to claim 4, wherein the deviation of the glass fiber content is less than 2.5 wt%, and / or, the flexural modulus is above 40 GPa, and / or, the flexural strength remains above 880 MPa.

6. A preparation device for a continuous fiber reinforced thermoplastic resin composite material, comprising a traction unit, a solution impregnation unit, a pressing unit, and a drying unit; the traction unit includes a continuous fiber inlet end and a composite material outlet end arranged oppositely; under the action of the continuous fiber inlet end, continuous fibers can sequentially pass through the impregnation unit for impregnation treatment, pass through the pressing unit for extrusion treatment, and pass through the drying unit for drying treatment.

7. The production apparatus according to claim 6, wherein, The solution impregnation unit includes an impregnation tank and at least one yarn spreading roller arranged in the impregnation tank; and / or, The pressing unit includes at least two pressing rollers, and every two of the pressing rollers are arranged oppositely and at intervals, and the continuous fibers can pass between the two oppositely arranged pressing rollers; and / or, The drying unit includes a drying box and a heating structure for adjusting the temperature of the drying box.

8. The preparation device according to claim 7, wherein A heat circulation structure for heating the impregnation solution is arranged in the impregnation tank; and / or, A vibration structure is arranged on the yarn spreading roller; and / or, The impregnation tank includes a tank body and a sealing cover that is detachably connected to the tank body; and / or, The preparation device further includes a solution recovery unit, which is disposed opposite to the pressing unit and is used to collect the solution from the pressing unit; and / or, On two relatively arranged extrusion rollers, grooves and protrusions that can engage with each other are respectively provided.

9. The production device according to claim 8, wherein, The two opposite ends of the solution recovery unit are respectively communicated with the solution impregnation unit and the drying unit; and / or, At least one guide roller is provided on the tank body for guiding the movement of the continuous fiber in the impregnation tank; and / or, A solvent recovery tank and a vacuum pump are provided on the drying oven.

10. Application of the continuous fiber reinforced thermoplastic resin composite material according to claim 4 or 5 in the preparation of pultruded products.

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