A bamboo-like hollow flexible composite core rod and its preparation method

Abstract

This invention discloses a bamboo-like hollow flexible composite mandrel and its preparation method. The hollow flexible composite mandrel includes an inner surface diaphragm layer, with several transverse ribs disposed inside the inner surface diaphragm layer, and a cavity between two transverse ribs. An intermediate diaphragm layer is disposed outside the inner surface diaphragm layer, and a resin adhesive and a thin-walled fiber tube are disposed between the inner surface diaphragm layer and the intermediate diaphragm layer. A fiberglass composite structure layer is disposed outside the intermediate diaphragm layer. The mandrel prepared by this invention is lightweight, effectively improving radial compressive strength and axial bending strength, and exhibits good flexibility. It avoids the splitting phenomenon along the length direction that is prone to occur in traditional hollow flexible composite mandrels when subjected to circumferential compression forces. The preparation method is simple, reduces manual operation, and lowers the cost of use.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to a bamboo-like hollow flexible composite mandrel and its preparation method. Background Technology

[0002] Because small-diameter, slender fiberglass composite materials are lighter and easier to transport and construct than traditional materials such as steel and ceramics of the same cross-section and strength, they have been widely used in power engineering, road and bridge engineering, and marine engineering as ultra-high voltage flexible composite insulator core rods, cable rods, and support rods, largely replacing traditional steel or rope locks. Composite materials are materials with new properties formed by combining two or more materials with different properties through physical or chemical methods at the macroscopic (microscopic) level.

[0003] Existing hollow flexible composite mandrels are heavy and have low radial compressive and axial bending strength. Furthermore, traditional hollow composite mandrels are prone to splitting along their length when subjected to circumferential compression forces, exhibiting poor flexibility, low practicality, and inconvenience in use. Additionally, the fabrication process is cumbersome, increasing manual labor and operating costs. Currently, no effective solutions have been proposed to address these technical problems. Summary of the Invention

[0004] To address the problems in related technologies, this invention proposes a bamboo-like hollow flexible composite core rod and its preparation method to overcome the aforementioned technical problems in existing related technologies. The purpose of this invention is that the core rod prepared by this invention is lightweight, effectively improves radial compressive strength and axial bending strength, has good flexibility, and avoids the tendency of traditional hollow flexible composite core rods to split along the length direction when subjected to circumferential compression force. The preparation method is simple, reduces manual operation, and lowers the cost of use.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A bamboo-like hollow flexible composite core rod includes an inner surface diaphragm layer, with a plurality of transverse ribs disposed inside the inner surface diaphragm layer and a cavity between two transverse ribs. An intermediate diaphragm layer is disposed outside the inner surface diaphragm layer. A resin adhesive and a thin-walled fiber tube are disposed between the inner surface diaphragm layer and the intermediate diaphragm layer. A fiberglass composite structure layer is disposed outside the intermediate diaphragm layer. The inner surface diaphragm layer, the resin adhesive, and the thin-walled fiber tube are combined to form a flexible structure layer.

[0007] Preferably, the cross-section of the mandrel is circular, square, or elliptical.

[0008] Preferably, the cavity is filled with air or nitrogen.

[0009] Preferably, the transverse ribs are made of wood fiber, glass fiber, silk fiber, polyester or nylon synthetic hybrid fiber.

[0010] Preferably, the thin-walled fiber tube is made of bamboo fiber or wood fiber.

[0011] Preferably, the inner surface membrane layer is made of polyetheretherketone, polyimide, or polyurethane.

[0012] Preferably, the intermediate spacer layer is made of glass fiber mat and polyester fiber nonwoven fabric.

[0013] Preferably, the thickness of the flexible structural layer is controlled at 3-5 mm, and the thickness of the intermediate spacer layer is controlled at 1.5-2 mm.

[0014] A method for preparing a bamboo-like hollow flexible composite core rod as described above includes the following steps:

[0015] Step 1: Laying up the functional material preform of the hollow flexible composite rod:

[0016] Using a fiberglass pipe pultrusion reinforcement material layup tooling, the raw materials are laid out sequentially along the radial direction, from the inside out as follows: the first layer is a natural bamboo fiber strip or wood fiber strip containing thin-walled conduits in its structure; the second layer is a middle septum layer made of silk fiber satin strip and polyester fiber nonwoven fabric; the third layer is fiberglass yarn and fiberglass strip.

[0017] Step 2: Fabrication of prepreg blanks for axial functional materials of hollow flexible composite rods:

[0018] The adhesive liquid is injected into the injection cavity mold by injection pultrusion, and the adhesive is fully impregnated with the layup functional material in step one to form a prepreg blank;

[0019] Step 3: Fabrication of transverse diaphragms using malleable material:

[0020] A premixed plastic material for molding is prepared by thoroughly mixing cross ribs with wood chopped fibers, glass chopped fibers, silk chopped fibers, polyester or nylon synthetic mixed chopped fibers, and a fixed amount of resin adhesive using a rubber mixing machine.

[0021] Step 4: Fabrication of the hollow flexible composite rod preform:

[0022] (1) During the pultrusion process, the hollow flexible composite rod axial functional material prepreg blank made in step two is pulled out from the injection cavity mold and enters the transverse rib making and hollow cavity blow molding mold.

[0023] (2) The inner surface diaphragm layer is made of polyether ether ketone, polyimide and polyurethane raw materials. The axial functional material prepreg blank of the hollow flexible composite rod made in step two is blown into the hollow flexible composite pipe by the blow molding machine. At the same time, the transverse rib forming mold inserts the transverse rib plastic into the cross section of the composite pipe at a certain speed along the direction perpendicular to the axis of the hollow flexible composite pipe. Together with the inner surface diaphragm strip formed by blow molding, the blow molding uses dry air or nitrogen to form a closed hollow cavity of a certain length, thus completing the production of the hollow flexible composite rod preform blank.

[0024] Step 5: Curing and shaping of the hollow flexible composite rod preform. The hollow flexible composite rod preform obtained in Step 4 is further pulled by the traction machine through the molding mold for molding and curing, and then pulled out of the machine head. The heating and curing process is divided into three stages: the temperature of the first preheating stage is 100℃~120℃, the temperature of the second gel stage is 135℃~145℃, and the temperature of the third curing stage is 170℃~180℃. Finally, a bamboo-like hollow flexible composite core rod is obtained.

[0025] Preferably, the adhesive solution in step two is an epoxy, anhydride, or vinyl resin system adhesive solution.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The present invention is a bamboo-shaped hollow flexible composite core rod and its preparation method. By setting the core rod to be hollow, the bamboo-shaped hollow flexible composite core rod is lighter in weight than the traditional solid core rod, making it convenient for people to use.

[0028] (2) The present invention is a bamboo-shaped hollow flexible composite core rod and its preparation method. By using transverse ribs, inner surface diaphragm layer, thin-walled fiber tube, resin adhesive, intermediate diaphragm layer and fiberglass composite structure layer, the radial compressive strength and axial bending strength of the bamboo-shaped hollow flexible composite core rod are comprehensively improved compared with the traditional hollow flexible composite core rod. That is, it gives the hollow flexible composite core rod good flexibility and avoids the traditional hollow flexible composite core rod from splitting along the length direction when subjected to circumferential compression force.

[0029] (3) The present invention is a hollow flexible composite core rod with a bamboo-like structure and its preparation method. The preparation method is simple, reduces manual operation, and lowers the cost of use. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the three-dimensional cross-section of the present invention;

[0031] Figure 2 This is a schematic diagram of the cross-section of the cavity in this invention;

[0032] Figure 3 This is a schematic diagram of the cross-section of the transverse diaphragm of the present invention.

[0033] In the attached diagram, the following are the reference numerals: 1. Inner surface diaphragm layer; 2. Transverse rib; 3. Cavity; 4. Intermediate diaphragm layer; 5. Resin adhesive; 6. Thin-walled fiber tube; 7. Fiberglass composite structure layer. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] Based on inner and outer diameter dimensions Taking the fabrication method of bamboo-shaped hollow flexible composite core rod as an example

[0037] A method for preparing a bamboo-like hollow flexible composite core rod includes the following steps:

[0038] Step 1: Laying up the functional material preform of the hollow flexible composite rod:

[0039] The fiberglass tube pultrusion reinforcement layering tooling is used to lay up the raw materials sequentially along the radial direction. The inner layer uses 40-count natural bamboo fiber yarn with mesh thin-walled conduits, with a layer thickness of 3.5mm; the middle separator layer uses 0.2mm thick polyester fiber nonwoven fabric, with a layer thickness of 1.5mm; and the outer composite layer uses 9600Tex fiberglass yarn, with a layer thickness of 5.5mm.

[0040] Step 2: Fabrication of prepreg blanks for axial functional materials of hollow flexible composite rods:

[0041] Bisphenol A epoxy resin / anhydride adhesive liquid is injected into the injection cavity mold by injection pultrusion, and the adhesive is fully impregnated with the layup functional material in step one to form a prepreg blank.

[0042] Step 3: Fabrication of transverse diaphragms using malleable material:

[0043] A premixed plastic material for molding was prepared by thoroughly mixing short wood fibers for transverse ribs with a 25% bisphenol A epoxy resin / anhydride adhesive using a rubber mixing mill.

[0044] Step 4: Fabrication of the hollow flexible composite rod preform:

[0045] (1) During the pultrusion process, the hollow flexible composite rod axial functional material prepreg blank made in step two is pulled out from the injection cavity mold and enters the transverse rib making and hollow cavity blow molding mold.

[0046] (2) The inner surface diaphragm layer is made of polyimide film. The hollow flexible composite rod is blown into the hollow flexible composite pipe by the blow molding machine through the inner wall of the axial functional material prepreg blank. At the same time, the transverse diaphragm is made of epoxy resin wood fiber clumps prepared in step three. The transverse diaphragm clumps are implanted into the cross section of the composite pipe at a certain speed along the direction perpendicular to the axis of the hollow flexible composite pipe. The inner surface diaphragm formed by blow molding is bagged with the diaphragm layer. The diaphragm layer is 0.2mm thick. Dry air is used to form a closed hollow cavity of a certain length for blow molding, thus completing the production of the hollow flexible composite rod preform.

[0047] Step 5: Curing and shaping of the hollow flexible composite rod preform. The hollow flexible composite rod preform obtained in Step 4 is further pulled by the traction machine through the molding mold for molding and curing, and then pulled out of the machine head. The heating and curing process is divided into three stages: the temperature of the first preheating stage is 100℃~120℃, the temperature of the second gel stage is 135℃~145℃, and the temperature of the third curing stage is 170℃~180℃. Finally, a bamboo-like hollow flexible composite core rod is obtained.

[0048] Example 2

[0049] Based on inner and outer diameter dimensions Taking the fabrication method of bamboo-shaped hollow flexible composite rod as an example

[0050] A method for preparing a bamboo-like hollow flexible composite core rod includes the following steps:

[0051] Step 1: Laying up the functional material preform of the hollow flexible composite rod:

[0052] Layup fabrication of functional material preform for hollow flexible composite rod: Using a fiberglass tube pultrusion reinforcement material layup tooling, raw materials are laid up sequentially along the radial direction. The inner layer uses natural wood fiber cloth tape with mesh thin-walled conduit, with a layup thickness of 3mm; the middle diaphragm layer uses 0.2mm thick silk fiber satin tape, with a layup thickness of 1.5mm; the outer composite layer uses 9600Tex glass fiber yarn, with a layup thickness of 6mm.

[0053] Step 2: Fabrication of prepreg blanks for axial functional materials of hollow flexible composite rods:

[0054] Bisphenol A type polyethylene ester adhesive liquid is injected into the injection cavity mold by injection pultrusion, and the adhesive is fully impregnated with the layup functional material in step one to form a prepreg blank;

[0055] Step 3: Fabrication of transverse diaphragms using malleable material:

[0056] A premixed plastic material for molding was prepared by thoroughly mixing chopped wood fibers for transverse diaphragms with a quantitative bisphenol A polyethylene ester adhesive solution containing 25% adhesive using a rubber mixing mill.

[0057] Step 4: Fabrication of the hollow flexible composite rod preform:

[0058] (1) During the pultrusion process, the hollow flexible composite rod axial functional material prepreg blank made in step two is pulled out from the injection cavity mold and enters the transverse rib making and hollow cavity blow molding mold.

[0059] (2) The inner surface diaphragm layer is made of polyester film and is blown into the hollow flexible composite pipe by the blow molding machine through the inner wall of the hollow flexible composite rod axial functional material prepreg blank. At the same time, the transverse diaphragm is made of epoxy resin wood fiber clumps prepared in step three. The transverse diaphragm clumps are implanted into the cross section of the composite pipe at a certain speed along the direction perpendicular to the axis of the hollow flexible composite pipe. It is bagged with the inner surface diaphragm formed by blow molding. The diaphragm layer is 0.2mm thick. Dry air is used to form a closed hollow cavity of a certain length, thus completing the production of the hollow flexible composite rod preform blank.

[0060] Step 5: Curing and shaping of the hollow flexible composite rod preform. The hollow flexible composite rod preform obtained in Step 4 is further pulled by the traction machine through the molding mold for molding and curing, and then pulled out of the machine head. The heating and curing process is divided into three stages: the temperature of the first preheating stage is 100℃~120℃, the temperature of the second gel stage is 135℃~145℃, and the temperature of the third curing stage is 170℃~180℃. Finally, a bamboo-like hollow flexible composite core rod is obtained.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hollow flexible composite core rod with a bamboo-like structure, characterized in that, The system includes an inner surface diaphragm layer (1), which has several transverse ribs (2) inside and a cavity (3) between two transverse ribs (2). An intermediate diaphragm layer (4) is provided outside the inner surface diaphragm layer (1). A resin adhesive (5) and a thin-walled fiber tube (6) are provided between the inner surface diaphragm layer (1) and the intermediate diaphragm layer (4). A fiberglass composite structure layer (7) is provided outside the intermediate diaphragm layer (4). The inner surface diaphragm layer (1), the resin adhesive (5), and the thin-walled fiber tube (6) are combined to form a flexible structure layer.

2. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The cavity (3) is filled with air or nitrogen.

3. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The transverse ribs (2) are made of wood fiber, glass fiber, silk fiber, polyester or nylon synthetic mixed fiber.

4. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The thin-walled fiber tube (6) is made of bamboo fiber or wood fiber.

5. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The inner surface membrane layer (1) is made of polyetheretherketone, polyimide, or polyurethane.

6. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The intermediate spacer layer (4) is made of glass fiber felt and polyester fiber nonwoven fabric.

7. The bamboo-like hollow flexible composite core rod according to claim 1, characterized in that, The thickness of the flexible structure layer is controlled at 3 to 5 mm, and the thickness of the intermediate spacer layer (4) is controlled at 1.5 to 2 mm.

8. A method for preparing a bamboo-like hollow flexible composite core rod as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Laying up the functional material preform of the hollow flexible composite rod: Using a fiberglass pipe pultrusion reinforcement material layup tooling, the raw materials are laid out sequentially along the radial direction, from the inside out as follows: the first layer is a natural bamboo fiber strip or wood fiber strip containing thin-walled conduits in its structure; the second layer is a middle septum layer made of silk fiber satin strip and polyester fiber nonwoven fabric; the third layer is fiberglass yarn and fiberglass strip. Step 2: Fabrication of prepreg blanks for axial functional materials of hollow flexible composite rods: The adhesive liquid is injected into the injection cavity mold by injection pultrusion, and the adhesive is fully impregnated with the layup functional material in step one to form a prepreg blank; Step 3: Fabrication of transverse diaphragms using malleable material: A premixed plastic material for molding is prepared by thoroughly mixing cross ribs with wood chopped fibers, glass chopped fibers, silk chopped fibers, polyester or nylon synthetic mixed chopped fibers, and a fixed amount of resin adhesive using a rubber mixing machine. Step 4: Fabrication of the hollow flexible composite rod preform: (1) During the pultrusion process, the hollow flexible composite rod axial functional material prepreg blank made in step two is pulled out from the injection cavity mold and enters the transverse rib making and hollow cavity blow molding mold. (2) The inner surface diaphragm layer is made of polyether ether ketone, polyimide and polyurethane raw materials. The axial functional material prepreg blank of the hollow flexible composite rod made in step two is blown into the hollow flexible composite pipe by the blow molding machine. At the same time, the transverse rib forming mold inserts the transverse rib plastic into the cross section of the composite pipe at a certain speed along the direction perpendicular to the axis of the hollow flexible composite pipe. Together with the inner surface diaphragm strip formed by blow molding, the blow molding uses dry air or nitrogen to form a closed hollow cavity of a certain length, thus completing the production of the hollow flexible composite rod preform blank. Step 5: Curing and shaping of the hollow flexible composite rod preform. The hollow flexible composite rod preform obtained in Step 4 is further pulled by the traction machine through the forming mold for molding and curing, and then pulled out of the machine head. The curing and shaping process is divided into three stages: the temperature of the first stage preheating stage is 100℃~120℃, the temperature of the second stage gel stage is 135℃~145℃, and the temperature of the third stage curing stage is 170℃~180℃. Finally, a bamboo-like hollow flexible composite core rod is obtained.

9. The method for preparing a bamboo-like hollow flexible composite core rod according to claim 8, characterized in that, The adhesive solution mentioned in step two is an epoxy, anhydride, or vinyl resin system adhesive solution.

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