Preparation method of degradable flow guide net

Abstract

The invention discloses a preparation method of a degradable flow guide net, which comprises the following steps: S1, selecting biomass fiber roving which comprises one or a combination of more of natural fibrilia, cotton yarn, coconut fiber and bamboo fiber, and the fineness of the roving is 5-80; s2, performing pre-drying treatment on the biomass fiber roving until the moisture regain is 0.1-5%; s3, performing yarn pretreatment on the biomass fiber roving subjected to the pre-drying treatment; s4, performing degradable thermoplastic resin surface layer sizing and dipping on the pretreated biomass fiber roving; s5, after sizing the biomass fiber roving, carrying out vacuum drying; s6, weaving a diversion net by adopting different gridding cloth weaving methods according to the design; step S7, hot pressing and cooling; in the step S4, the slurry used for sizing comprises modified starch and deionized water, and the solid content of the slurry is 5-15%. According to the preparation method disclosed by the invention, the product can be endowed with the characteristic of complete degradability.

Description

Technical Field

[0001] The invention belongs to the technical field of flow-guiding materials in composite material molding processes, and particularly relates to a preparation method of a degradable flow-guiding net. Background Art

[0002] Composite materials, with their advantages of lightweight and high strength, are widely used in aerospace, automotive, construction, new energy, rail transit, infrastructure, sports and leisure, and other fields. Composite molding processes are the foundation and prerequisite for the development of the composite materials industry. As the application of composite materials expands, composite molding processes have evolved from initially relying on manual hand lay-up molding to machine-assisted injection molding, compression molding, pultrusion, and winding molding, and more recently, the rise of autoclave molding and vacuum-assisted resin transfer molding.

[0003] Vacuum-assisted resin transfer (VART) is a low-cost composite molding method that injects liquid resin into preformed fiber-reinforced materials. A flow mesh is a highly permeable flow medium used in VAT of composites. Its three-dimensional mesh structure facilitates resin flow and penetration. Widely used in vacuum infusion molding of resin-based composites, it allows for rapid and uniform resin penetration into every part of the product, ensuring uniformity and consistency in the composite structure.

[0004] Currently, most flow guide nets are extruded or woven from non-degradable resins such as polypropylene and polyethylene. This non-degradability poses certain environmental risks. With the continued development of vacuum-assisted resin transfer (VART), more and more composite products will adopt this molding process, and the specifications of the composite materials produced are also increasing, which in turn increases the demand for flow guide nets. For example, with the rapid application and development of composite materials in the wind power sector, in the manufacture of megawatt-class wind turbine blades, the flow guide net used for a single blade shell and other components can reach hundreds of square meters. Summary of the Invention

[0005] In response to the technical problems existing in the prior art, the present invention provides a method for preparing a degradable guide net, which is completely degradable to replace the existing guide net made of non-degradable materials. The guide net can be customized with integrated structures of various shapes according to different process requirements.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] A method for preparing a degradable diversion net comprises the following steps:

[0008] Step S1, selecting biomass fiber roving, including one or more of natural hemp fiber, cotton yarn, coconut fiber, and bamboo fiber, with a roving fineness of 5-80 count;

[0009] Step S2, pre-drying the biomass fiber roving until the moisture regain is 0.1-5%;

[0010] Step S3, performing yarn pretreatment on the pre-baked biomass fiber roving;

[0011] Step S4, sizing and impregnating the pretreated biomass fiber roving with a degradable thermoplastic resin surface;

[0012] Step S5, after the biomass fiber roving is sized, vacuum drying is performed;

[0013] Step S6, weaving a diversion net using different mesh weaving methods according to the design;

[0014] Step S7, after weaving and forming, hot pressing and cooling;

[0015] The degradable thermoplastic resin includes a mixture of one or more of polylactic acid, polycaprolactone, degradable polyethylene terephthalate, polyvinyl alcohol, poly 3-hydroxyalkanoate, poly 3-hydroxybutyrate, polyhydroxyvalerate, polybutylene succinate, and thermoplastic starch;

[0016] In step S4, the sizing material components used for sizing include modified starch and deionized water, the slurry solid content is 5-15%, the slurry temperature is 20-90° C., the sizing speed during sizing is 30-100 m / min, and the sizing tension is 50-200 cN.

[0017] As a further improvement of the above technical solution:

[0018] In the above technical solution, preferably, in step S1, the natural hemp fiber is one or more combinations of jute fiber, hemp fiber, ramie fiber, kenaf fiber, flax fiber, kenaf fiber, hemp fiber, and abaca fiber.

[0019] In the above technical solution, preferably, in step S3, the pretreatment adopts an ethanol pretreatment method: the natural fiber yarn is immersed in anhydrous ethanol for 5-15 minutes at a temperature of 20°C and a relative humidity of 65%. The ethanol immersion drying or normal temperature and pressure plasma treatment method is used to enhance the interfacial bonding strength between the fiber and the degradable thermoplastic resin, improve the wettability of the yarn and the sizing liquid penetration ability in the subsequent sizing process, and thus improve the sizing quality.

[0020] The normal temperature and pressure plasma treatment method is: using normal pressure plasma jet equipment, the gases used are helium and one or two of nitrogen, oxygen, hydrogen, argon, and air, the gas flow ratio is 90-100:0-10, the radio frequency range is 1-40kHz, the treatment time is 10-600s, and the treatment power is 0.1-150w, depending on the specific yarn fineness.

[0021] In the above technical solution, preferably, in step S3, the pretreatment adopts a normal temperature and pressure plasma treatment method, and the gases used are helium and one or two of nitrogen, oxygen, hydrogen, argon, and air, with a gas flow ratio of 90-100:0-10, a radio frequency range of 1-40kHz, a treatment time of 10-600s, and a treatment power of 0.1-150w.

[0022] In the above technical solution, preferably, in step S5, the vacuum degree is -50-100 kPa, the temperature is 40-100° C., and the time is 4-12 h.

[0023] In the above technical solution, preferably, in step S6, the diversion mesh has a pore size of 1mm-5mm, a mesh thickness of 0.9-1.2mm, and a weight of 90-160g. By adjusting weaving parameters such as warp and weft density and mesh structure, yarns of varying thicknesses can be used for weaving to achieve a resin diversion effect that meets design requirements.

[0024] In the above technical solution, preferably, in step S7, the hot pressing temperature is 120°C-180°C, the pressing time is 5-15 minutes, and the pressure is 5-15 MPa. The hot pressing-cooling process allows the surface thermoplastic resin at the interweaving points to fuse together, preventing the natural fiber mesh flow-guiding material from interweaving and slipping, thereby ensuring manufacturing quality.

[0025] The preparation method of the degradable diversion net provided by the present invention has the following advantages compared with the prior art:

[0026] (1) The preparation method of the degradable guide net of the present invention is to carry out sizing and impregnation of the surface of the biomass fiber roving with a degradable thermoplastic resin, thereby solving the problem of the biomass fiber mesh cloth shedding; on the other hand, it reduces the amount of degradable resin used, reduces the product cost, and makes it more convenient to reinforce the interweaving points after the net is formed.

[0027] (2) The present invention's method for preparing a degradable flow-guiding mesh has developed a biomass fiber mesh flow-guiding material with a degradable resin coating suitable for vacuum-assisted resin transfer processes for composite materials. This material is fully degradable and can replace existing flow-guiding meshes made of non-degradable materials, thereby achieving green manufacturing and sustainable development of resin-based composite materials. Unlike the extrusion process of traditional flow-guiding meshes, natural fiber mesh can be prepared using various weaving processes, offering greater structural flexibility and adaptability to a variety of resin infusion speeds. This allows for effective control of the resin flow state, thereby improving the reliability and product quality of the complex product molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of a method for preparing a degradable diversion net.

[0029] Figure 2 It is the degradable PLA-ramie diversion net of Example 1 of the present invention.

[0030] Figure 3 The degradable PVA-jute diversion net of Example 2 of the present invention.

[0031] Figure 4 It is the degradable PCL-cotton diversion net of Example 3 of the present invention. DETAILED DESCRIPTION

[0032] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0033] Example 1

[0034] Step S1, selecting 100% ramie with a yarn fineness of 10.

[0035] In step S2, the ramie roving is dried to obtain a moisture regain of 1%.

[0036] Step S3: Plasma-treating the ramie roving. Helium is introduced into a normal pressure plasma treatment device with a helium flow rate of 500 L / h-2000 L / h, a radio frequency of 12.56 MHz, a power of 30 W, and a treatment time of 30 seconds.

[0037] Step S4: Sizing the pretreated ramie yarn with a polylactic acid (PLA) resin slurry. The slurry formulation is PLA, dichloromethane, concentration / solid content is 10%, slurry temperature is 20°C, sizing speed is 45m / min, sizing rate is 10%, and sizing tension is 35kN.

[0038] Step S5: vacuum drying after sizing, with a vacuum degree of -80 kPa, a temperature of 70° C., and a drying time of 4 hours.

[0039] Step S6: The ramie yarn after being sized with polylactic acid resin is knitted into a knotless rope net or a warp-knitted structure with warp and weft yarns of different counts to obtain a PLA-coated ramie fabric.

[0040] Step S7, after hot pressing and cooling, a green and degradable PLA-ramie guide net is obtained, such as Figure 2 shown.

[0041] Example 2

[0042] 100% jute was selected, and the yarn fineness was 5 counts. After pre-drying, the moisture regain of the jute roving was 2.5%. The jute roving was soaked in anhydrous ethanol for 10 minutes and dried at room temperature. The pretreated jute yarn was then sized with polyvinyl alcohol (PVA) resin slurry. The slurry formula is PVA and deionized water, the concentration / solid content is 15%, the slurry temperature is 90°C, the sizing speed is 100m / min, and the sizing tension is 40kN. After sizing, vacuum drying is carried out with a vacuum degree of -100kPa, a temperature of 100°C, and a drying time of 6h. The jute yarn after sizing with PVA resin is plain woven with a warp and weft density of 50×50 to obtain a PVA-coated jute plain fabric. After hot pressing-cooling, a green and degradable PVA-jute diversion net is obtained, such as Figure 3 shown.

[0043] Example 3

[0044] 100% cotton was selected, and the yarn fineness was 32 counts. After pre-drying, the moisture regain of the cotton yarn was 3.5%. The cotton yarn was plasma treated. Helium was introduced into the normal pressure plasma treatment equipment, the helium flow rate was: 75ml / min, the radio frequency was 14.72MHz, the power was 50w, and the treatment time was 60s. Then the pretreated cotton yarn was sized with polycaprolactone (PCL) resin slurry. The slurry formula is PCL, dichloromethane, the concentration / solid content is 5%, the slurry temperature is 40°C, the sizing speed is 50m / min, the sizing tension is 26kN, and the vacuum drying treatment is carried out after sizing, the vacuum degree is -50kPa, the temperature is 40°C, and the drying time is 12h. The cotton yarn after PCL resin sizing is woven to obtain a PCL-coated all-cotton grid structure. After hot pressing-cooling, a green and degradable PCL-cotton guide net is obtained, such as Figure 4 shown.

[0045] The above examples are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modifications, equivalent variations, and modifications to the above examples that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a degradable diversion net, characterized in that: The following steps are involved: Step S1, selecting biomass fiber roving, including one or more of natural hemp fiber, cotton yarn, coconut fiber, and bamboo fiber, with a roving fineness of 5-80 count; Step S2, pre-drying the biomass fiber roving until the moisture regain is 0.1-5%; Step S3, performing yarn pretreatment on the pre-baked biomass fiber roving; Step S4, sizing and impregnating the pretreated biomass fiber roving with a degradable thermoplastic resin surface; Step S5, after the biomass fiber roving is sized, vacuum drying is performed; Step S6, weaving a diversion net using different mesh weaving methods according to the design; Step S7, after weaving and forming, hot pressing and cooling; The degradable thermoplastic resin includes a mixture of one or more of polylactic acid, polycaprolactone, degradable polyethylene terephthalate, polyvinyl alcohol, poly 3-hydroxyalkanoate, poly 3-hydroxybutyrate, polyhydroxyvalerate, polybutylene succinate, and thermoplastic starch; In step S4, the sizing material components used for sizing include modified starch and deionized water, the slurry solid content is 5-15%, the slurry temperature is 20-90° C., the sizing speed during sizing is 30-100 m / min, and the sizing tension is 50-200 cN.

2. The method for preparing the degradable flow-guiding net according to claim 1, characterized in that: In step S1, the natural hemp fiber is one or more combinations of jute fiber, hemp fiber, ramie fiber, kenaf fiber, flax fiber, kenaf fiber, hemp fiber, and abaca fiber.

3. The method for preparing the degradable diversion net according to claim 1, characterized in that: In step S3, the pretreatment adopts an ethanol pretreatment method: the natural fiber yarn is immersed in anhydrous ethanol for 5-15 minutes at a temperature of 20° C. and a relative humidity of 65%.

4. The method for preparing a degradable flow-guiding net according to claim 1, wherein: In step S3, the pretreatment adopts a normal temperature and normal pressure plasma treatment method, the gases used are helium and one or two of nitrogen, oxygen, hydrogen, argon, and air, the gas flow ratio is 90-100:0-10, the radio frequency range is 1-40kHz, the treatment time is 10-600s, and the treatment power is 0.1-150w.

5. The method for preparing the degradable diversion net according to claim 1, characterized in that: In step S5, the vacuum degree is -50-100 kPa, the temperature is 40-100° C., and the time is 4-12 hours.

6. The method for preparing the degradable flow-guiding net according to claim 5, characterized in that: In step S6, the guide mesh has an aperture of 1 mm to 5 mm, a mesh thickness of 0.9 to 1.2 mm, and a gram weight of 90 to 160 g.

7. The method for preparing the degradable flow-guiding net according to claim 5, characterized in that: In step S7, the hot pressing temperature is 120° C.-180° C., the pressing time is 5 min-15 min, and the pressure is 5 MPa-15 MPa.

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