Blended yarn integrated woven grid reinforcing rib composite material and preparation method thereof

Abstract

The invention discloses a blended yarn integrated woven grid reinforcing rib composite material and a preparation method, and belongs to the technical field of textiles. The natural fibers and the resin fibers are blended according to a certain proportion, the obtained blended yarns are integrally woven to obtain the grid reinforcing ribs, and the fibers at the junctions of the warps and the wefts of the reinforcing ribs penetrate through pores generated in the twisting process, so that nodes do not exist at the junctions of the warps and the wefts of the reinforcing ribs; the reinforcing rib integrally woven by the blend fibers is put into an interlayer of natural fiber woven cloth and a fiber felt material for layering, a composite material laminated board is prepared in a hot mold pressing mode, and meanwhile, the effects of self-adhesion and structure enhancement are achieved. Compared with a non-woven fabric, the reinforcing rib has better mechanical performance, and compared with a reinforcing rib prepared by a traditional weaving method, the reinforcing rib does not have nodes like the non-woven fabric.

Description

Technical Field

[0001] The invention belongs to the field of textile technology, and specifically relates to a blended fiber integrated woven grid reinforcement composite material and a preparation method thereof. Background Art

[0002] Lamellar grid reinforcements are widely used to improve the performance of composite laminates. Environmental protection and energy saving have become the slogans of the times. Environmentally friendly and high-yield natural fibers can replace metal in some application scenarios to prepare grid reinforcements. Natural fibers have characteristics that are in line with the characteristics of the times, such as environmental protection and high yield. Some composite reinforcement structures prepared with them can ensure performance while giving composite materials the excellent characteristics of natural fibers, and have become an important part of future material development.

[0003] Most mesh reinforcements are made of metal materials. Although they have good mechanical properties, they are heavy and it is difficult to meet the requirements of lightweight products. The mesh reinforcement structure prepared by the traditional weaving method will produce nodes at the intersection of the warp and weft lines, which will cause stress concentration problems in the subsequent use of the reinforced structure. The mesh reinforcement prepared by the present invention adopts weaving means. The traditional weaving method will inevitably produce nodes on the surface of the woven fabric, which will cause stress concentration in the subsequent preparation of the composite material and affect the product performance. Different from non-woven fabrics, the present invention uses weaving means to eliminate the influence of nodes.

[0004] Lamellar grid reinforcement as interlayer is a common method for reinforcing composite panels. The principle used by the present invention is that the place where the fibers at the intersection of the warp and weft lines of the reinforcement pass through is the pores generated during the twisting process of the blended fibers. By comparing the non-woven fabric with the traditional weaving method, the new weaving method is used to eliminate the influence of the nodes; in order to achieve different reinforcement effects, natural fibers of different proportions and types are blended with resin fibers to obtain blended yarns. This blended yarn not only has the reinforcement effect of natural fibers but also has the self-adhesiveness of resin fibers; the weaving method of the present invention eliminates the stress concentration problem caused by the nodes generated by the traditional weaving method; then the grid reinforcement is placed in the interlayer between the woven cloth and the fiber felt to form a preform, and the preform is molded into a composite laminate by hot molding, which finally achieves the effect of reinforcing the structure of the composite laminate. Summary of the invention

[0005] In order to solve the problems of surface nodes generated by traditional weaving methods and poor mechanical properties of composite materials, the present invention proposes a composite material of blended fiber integrated woven grid reinforcement and a preparation method. The technical solution adopted by the present invention is as follows: A method for preparing a composite material of a blended fiber integrated woven grid reinforcement rib, the specific steps of the method are: (1) Pretreatment: Mechanically degumming the natural continuous fibers at room temperature; the specific method is to boil the natural continuous fibers in 100° C. boiling water for 1-3 hours; the natural continuous fibers are a combination of one or more of flax fibers, jute fibers, and hemp fibers; (2) blending the natural continuous fibers treated in step (1) with resin fibers in a ratio of 4-7 strands to 6-3 strands to obtain a blended yarn; the resin fibers are continuous fibers; (3) The prepared blended yarn is woven to obtain lamellar mesh reinforcement ribs. The weaving method is to take the natural / resin fiber blended yarn and place it on a workbench, take another blended yarn, cross the two in an orthogonal manner, and make the latter pass through the gaps generated by the internal twisting of the former. Through this staggered weaving, stable lamellar mesh reinforcement ribs are formed, that is, the blended fiber integrated woven mesh reinforcement rib composite material; the twist degree of the blended yarn is 30 to 80 twists per meter.

[0006] Preferably, the fineness of the natural fiber is 0.5 dtex; the fineness of the resin fiber is 0.5 dtex.

[0007] Preferably, the blending method in step (2) is longitudinal blending or wrapping blending.

[0008] The present invention also provides a blended fiber integrated woven grid reinforcement composite material prepared by the above method.

[0009] The present invention also provides a method for preparing a composite laminate based on the blended fiber integrated woven grid reinforcement composite material, the method comprising the following steps: (1) Pretreatment: Mechanically degumming the natural continuous fibers at room temperature; the specific method is to boil the natural continuous fibers in 100° C. boiling water for 1-3 hours; the natural continuous fibers are a combination of one or more of flax fibers, jute fibers, and hemp fibers; (2) blending the natural continuous fibers treated in step (1) with resin fibers in a ratio of 4-7 strands to 6-3 strands to obtain a blended yarn; the resin fibers are continuous fibers; (3) placing the blended yarn prepared in step (2) into a knitting machine to knit a knitted fabric; the knitted fabric is in the form of a combination of one or more of a non-woven knitted fabric, a warp and weft knitted fabric, and a three-dimensional knitted fabric; (4) forming a fiber felt from the blended yarn prepared in step (2); (5) The mesh reinforcement ribs are alternately layered with woven fabrics and fiber felts to obtain a preform; the fiber composition and ratio of the woven fabrics, mesh reinforcement ribs and woven fabrics are consistent; if the mesh reinforcement ribs are composed of 60wt% natural fibers and 40wt% resin fibers, then the woven fabrics and resin fiber felts also contain the same types of natural fibers and resin fibers, and the ratio is also 60wt% natural fibers and 40wt% resin fibers.

[0010] (6) The preform is placed in a molding machine and, under heating conditions, a hot molding process is used to prepare a natural fiber in-situ reinforced composite laminate.

[0011] Preferably, the grid reinforcement ribs, the woven fabric, and the resin fiber felt are laid in a sandwich structure.

[0012] Preferably, the weaving method in step (3) is manual weaving or mechanical weaving by a weaving machine.

[0013] Preferably, the temperature of the hot pressing process in step (6) is 150-230° C. and the pressure is 1-10 MPa.

[0014] Preferably, the hot pressing process in step (6) adopts one-stage molding or multi-stage molding.

[0015] Preferably, after the hot pressing in step (6) is completed, the prepared blended yarn braided fabric is cooled by mechanical cooling or air cooling to obtain an in-situ reinforced fiber reinforced composite plate.

[0016] Beneficial effects of the present invention: The present invention uses natural fibers and resin fibers to be integrated into a blended fiber grid reinforcement according to a certain ratio. The fibers at the intersection of the warp and weft of the reinforcement pass through the pores generated during the twisting process, so that there are no nodes at the intersection of the warp and weft of the reinforcement. The reinforcement woven with the blended fibers is placed in the interlayer of the natural fiber woven cloth and the fiber felt material for layering, and is prepared into a composite laminate by hot molding, which simultaneously achieves the effects of self-adhesion and structural reinforcement. The reinforcement has better mechanical properties than non-woven fabrics, and has no nodes like non-woven fabrics compared to reinforcements prepared by traditional weaving methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the preparation of the mesh reinforcement and the woven fabric in the present invention; Figure 2 is a flow chart for preparing the composite laminate of the present invention; Figure 3 It is a schematic diagram of the structure of the mesh reinforcement braiding node in the present invention.

[0018] Figure 4The invention discloses a process flow chart of a method for preparing a composite material of a blended fiber integrated woven grid reinforcement.

[0019] Among them: 1- natural fiber and resin fiber; 2- spinning machine; 3- blended yarn; 4- weaving machine; 5- woven cloth; 6- grid reinforcement, 7- fiber felt; 5- woven cloth; 6- grid reinforcement; 8- molding machine; 9- composite laminate. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further explained and illustrated below through specific embodiments in conjunction with the accompanying drawings.

[0021] Example 1 The raw materials of this embodiment are hemp fiber and polypropylene fiber, and the specific implementation method includes the following steps: (1) Pretreatment: Mechanical degumming of hemp fiber at room temperature can remove impurities on the surface of hemp fiber and remove pectin, hemicellulose, lignin and other colloids, thereby improving its softness and spinnability. Then boil it in boiling water for 1 hour to further enhance the spinnability of hemp fiber, improve its spinning effect with polypropylene fiber, and improve the overall performance of blended yarn.

[0022] (2) blending the hemp fiber obtained after the treatment in step (1) with the polypropylene fiber in a certain proportion to obtain a blended yarn, wherein the ratio of the natural fiber to the resin fiber is 4 strands:6 strands; (3) The prepared blended yarn is placed in a weaving machine and weaved into a woven cloth using a plain weave method.

[0023] (4) The prepared blended yarn is integrated by hand weaving to obtain a lamellar mesh reinforcement. The weaving method is to take the hemp / polypropylene fiber blended yarn and place it on the workbench longitudinally, labeled 6-1; take another blended yarn, labeled 6-2, and cross the two in an orthogonal manner, and pass through the gaps generated by the internal twisting of the longitudinal blended yarn 6-1 in the transverse direction. Through this staggered weaving, a stable lamellar mesh reinforcement is formed; the twist degree of the blended yarn is 30 to 80 twists per meter.

[0024] (5) The woven cloth woven in step (3), the mesh reinforcement ribs woven in step (4), and the resin fiber felt (made of 40wt% hemp fiber and 60wt% polypropylene fiber) are layered to obtain a preform with a sandwich structure. The layering method is to alternately layer a layer of woven cloth, a layer of mesh reinforcement ribs, and a layer of resin fiber felt. The preform consists of two layers of woven cloth, two layers of mesh reinforcement ribs, and a layer of resin fiber felt, wherein both ends of the preform are woven cloth.

[0025] (6) The preform is placed in a mold, and the mold is placed in a molding machine. Under heating conditions, the molding machine is heated to 180°C, and the preform is molded at a pressure of 2 MPa for 3 minutes. After the molding is completed, the mold is taken out and placed in room temperature for air cooling to obtain the target laminate.

[0026] Example 2 The raw materials of this embodiment are flax fiber and ABS resin fiber, and the specific implementation method includes the following steps: (1) Pretreatment: The flax fibers are mechanically degummed at room temperature to remove impurities on the surface of the flax fibers and remove pectin, hemicellulose, lignin and other colloids, thereby improving their softness and spinnability. The fibers are then boiled in boiling water for 1 hour to further enhance their spinnability, improve their spinning effect with ABS resin fibers, and improve the overall performance of the blended yarn.

[0027] (2) The flax fiber obtained after the treatment in step (1) is blended with ABS resin fiber in a certain proportion to obtain a blended yarn, wherein the ratio of natural fiber to resin fiber is 5 strands:5 strands.

[0028] (3) The prepared blended yarn is placed in a weaving machine and weaved into a woven cloth using a plain weave method.

[0029] (4) The prepared blended yarn is integrated into a layered grid reinforcement by manual weaving; the twist degree of the blended yarn is 30 to 80 twists per meter.

[0030] (5) The woven cloth woven in step (3), the mesh reinforcement ribs woven in step (4), and the resin fiber felt (made of 50wt% flax fiber and 50wt% ABS resin fiber) are layered to obtain a preform with a sandwich structure. The layering method is to alternately layer a layer of woven cloth, a layer of mesh reinforcement ribs, and a layer of resin fiber felt. The preform consists of two layers of woven cloth, two layers of mesh reinforcement ribs, and a layer of resin fiber felt, wherein both ends of the preform are woven cloth.

[0031] (6) The preform is placed in a mold, and the mold is placed in a molding machine. Under heating conditions, the molding machine is heated to 210°C, and the preform is molded at a pressure of 3 MPa for 3 minutes. After the molding is completed, the mold is taken out and placed in room temperature for air cooling to obtain the target laminate.

[0032] Example 3 This embodiment uses jute fiber and nylon fiber as synthetic fibers, and the specific implementation method includes the following steps: (1) Pretreatment: Mechanical degumming of jute fiber is performed at room temperature. Mechanical degumming can remove impurities on the surface of jute fiber and remove pectin, hemicellulose, lignin and other colloids, thereby improving its softness and spinnability. Then, the jute fiber is boiled in boiling water for 1 hour to further enhance the spinnability of jute fiber, improve its spinning effect with nylon fiber, and improve the overall performance of the blended yarn.

[0033] (2) blending the jute fiber obtained after the treatment in step (1) with nylon fiber in a certain proportion to obtain a blended yarn, wherein the ratio of natural fiber to resin fiber is 7 strands:3 strands; (3) The prepared blended yarn is placed in a weaving machine and weaved into a woven cloth using a plain weave method.

[0034] (4) The prepared blended yarn is integrated into a layered grid reinforcement by manual weaving; the twist degree of the blended yarn is 30 to 80 twists per meter.

[0035] (5) The woven cloth woven in step (3), the mesh reinforcement ribs woven in step (4), and the resin fiber felt (made of 60wt% jute fiber and 40wt% nylon fiber) are layered to obtain a preform with a sandwich structure. The layering method is to alternately layer a layer of woven cloth, a layer of mesh reinforcement ribs, and a layer of resin fiber felt. The preform consists of two layers of woven cloth, two layers of mesh reinforcement ribs, and a layer of resin fiber felt, wherein both ends of the preform are woven cloth.

[0036] (6) The preform is placed in a mold, and the mold is placed in a molding machine. Under heating conditions, the molding machine is heated to 220°C, and the preform is molded at a pressure of 2 MPa for 3 minutes. After the molding is completed, the mold is taken out and placed in room temperature for air cooling to obtain the target laminate.

[0037] Example 4 This example serves as a control group. The woven cloth, fiber felt and raw materials used in this example are the same as those described in Example 1. The specific implementation method includes the following steps: (1) blending flax fiber and polypropylene fiber in a ratio of 4 strands:6 strands to obtain blended yarn; weaving the obtained blended yarn using a traditional weaving method to obtain a woven fabric with a grid-like reinforcement structure; (2) The woven cloth and the resin fiber felt (made of 40wt% hemp fiber and 60wt% polypropylene fiber) are layered to obtain a preform with a sandwich structure. The layering method is to alternately layer a layer of woven cloth and a layer of resin fiber felt. The preform consists of two layers of woven cloth and a layer of resin fiber felt, and both ends of the preform are woven cloth.

[0038] (3) Place the preform in a mold and place it in a molding press. The molding press is heated to 180°C and the preform is molded for 3 minutes at a pressure of 2 MPa. After the molding is completed, the mold is taken out and placed at room temperature for air cooling to obtain a composite board.

[0039] It should be noted that the weaving method of the lamellar grid reinforcement of the present invention is different from the traditional yarn weaving method in which the yarn is woven alternately in the longitudinal / lateral direction. The two blended yarns are interwoven at the nodes, so that the nodes can tightly connect the two blended yarns together.

[0040] The following describes the weaving method in detail by taking the weaving method of a blended yarn of 4 strands of yarn and a blended yarn of 4 strands of yarn as an example. Figure 3 As shown, the first blended yarn 6-1 and the second blended yarn 6-2 are respectively composed of 4 yarns; wherein the first blended yarn 6-1 is composed of the first blended yarn No. 1 6-1-1, the first blended yarn No. 2 6-1-2, the first blended yarn No. 3 6-1-3 and the first blended yarn No. 3 6-1-4, and the second blended yarn 6-2 is composed of the second blended yarn No. 1 6-2-1, the second blended yarn No. 2 6-2-2, the second blended yarn No. 3 6-2-3 and the second blended yarn No. 4 6-2-4; The first blended yarn 6-1-1 No. 1 is located at the top, the first blended yarn 6-1-2 No. 2 passes under the second blended yarn 6-2-4 No. 4, and over the second blended yarn 6-2-2 No. 2 and the second blended yarn 6-2-3 No. 3; the first blended yarn 6-1-3 No. 3 passes under the second blended yarn 6-2-1 No. 1, the second blended yarn 6-2-3 No. 3, and the second blended yarn 6-2-4 No. 4, and over the second blended yarn 6-2-2 No. 2; the first blended yarn 6-1-4 No. 4 passes under the second blended yarn 6-2-1 No. 1, and over the second blended yarn 6-2-3 No. 3 and the second blended yarn 6-2-4 No. 4; The second blended yarn No. 1 6-2-1 passes between the first blended yarn No. 1 6-1-1 and the first blended yarn No. 4 6-1-4, the second blended yarn No. 2 6-2-2 is located at the bottom, the second blended yarn No. 3 6-2-3 passes between the first blended yarn No. 3 6-1-3 and the first blended yarn No. 2 6-1-2, and the second blended yarn No. 4 6-2-4 passes between the first blended yarn No. 1 6-1-1 and the first blended yarn No. 2 6-1-2.

[0041] The present invention tests the tensile strength, shear strength and impact strength of the composite plate reinforced with integrated woven mesh reinforcement ribs of the blended fibers obtained in Examples 1 to 4, and the results are shown in Table 1. The test results show that the composite plate reinforced with mesh reinforcement ribs of the hybrid fiber sheet structure of the present invention is superior in mechanical properties, and has better performance than the ordinary laminated plate in Example 4 that is not in-situ reinforced with woven fabrics.

[0042] Table 1 The above content discloses the basic principle, key technology and main advantage of the present invention. Professional and technical personnel should understand that the embodiments provided are intended to illustrate the core concept of the present invention and do not limit its application. Under the premise of complying with the spirit and scope of protection of the present invention, the present invention allows various adjustments and improvements. All these changes and improvements, as long as they comply with the scope of protection of the present invention, should be regarded as part of the present invention. Any changes within the scope of protection or equivalent thereto should be regarded as the scope of coverage of the present invention.

Claims

1. A method for preparing a composite material of blended fiber integrated woven grid reinforcement, characterized in that: The specific steps of this method are: (1) Pretreatment: Mechanically degumming the natural continuous fibers at room temperature; the specific method is to boil the natural continuous fibers in 100° C. boiling water for 1-3 hours; the natural continuous fibers are a combination of one or more of flax fibers, jute fibers, and hemp fibers; (2) blending the natural continuous fibers treated in step (1) with resin fibers in a ratio of 4-7 strands to 6-3 strands to obtain a blended yarn; the resin fibers are continuous fibers; (3) The prepared blended yarn is woven to obtain lamellar mesh reinforcement ribs. The weaving method is to take the natural / resin fiber blended yarn and place it on a workbench, take another blended yarn, cross the two in an orthogonal manner, and make the latter pass through the gaps generated by the internal twisting of the former. Through this staggered weaving, stable lamellar mesh reinforcement ribs are formed, that is, the blended fiber integrated woven mesh reinforcement rib composite material; the twist degree of the blended yarn is 30 to 80 twists per meter.

2. The method for preparing the blended fiber integrated woven grid reinforcement composite material according to claim 1, characterized in that: The fineness of the natural fiber is 0.5 dtex; the fineness of the resin fiber is 0.5 dtex.

3. The method for preparing the blended fiber integrated woven grid reinforcement composite material according to claim 1, characterized in that: The blending method in step (2) is longitudinal blending or wrapping blending.

4. A composite material of blended fiber integrated woven grid reinforcement prepared by the method as described in any one of claims 1 to 3.

5. A method for preparing a composite laminate based on the blended fiber integrated woven grid reinforcement composite material according to claim 4, characterized in that: The steps of this method are: (1) Pretreatment: Mechanically degumming the natural continuous fibers at room temperature; the specific method is to boil the natural continuous fibers in 100° C. boiling water for 1-3 hours; the natural continuous fibers are a combination of one or more of flax fibers, jute fibers, and hemp fibers; (2) blending the natural continuous fibers treated in step (1) with resin fibers in a ratio of 4-7 strands to 6-3 strands to obtain a blended yarn; the resin fibers are continuous fibers; (3) placing the blended yarn prepared in step (2) into a knitting machine to knit into a knitted fabric; (4) forming a fiber felt from the blended yarn prepared in step (2); (5) alternately layering mesh reinforcement ribs, woven fabrics, and fiber felt to obtain a preform; the fiber composition and ratio of the woven fabrics, mesh reinforcement ribs, and woven fabrics are consistent; (6) The preform is placed in a molding machine and, under heating conditions, a hot molding process is used to prepare a natural fiber in-situ reinforced composite laminate.

6. The method for preparing the composite laminate according to claim 5, characterized in that: The grid reinforcement, woven fabric and resin fiber felt are laid in a sandwich structure.

7. The method for preparing the composite laminate according to claim 5, characterized in that: The weaving method in step (3) is manual weaving or mechanical weaving by a weaving machine.

8. The method for preparing the composite laminate according to claim 5, characterized in that: The temperature of the hot pressing process in step (6) is 150-230°C and the pressure is 1-10MPa.

9. The method for preparing the composite laminate according to claim 5, characterized in that: In step (6), the hot pressing process adopts one-stage molding or multi-stage molding.

10. The method for preparing a composite laminate according to claim 5, characterized in that: After the hot pressing in step (6) is completed, the prepared blended yarn braided fabric is cooled by mechanical cooling or air cooling to obtain an in-situ reinforced fiber reinforced composite plate.

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