A bamboo-wrapped pipe structure and a method for producing the same

Abstract

The application discloses a kind of bamboo winding pipe structure and its production method, by bamboo fiber reinforced material unit and adhesive composition, the bamboo fiber reinforced material unit includes bamboo short fiber felt layer, 0 ° direction bamboo silk and bamboo silk weaving layer, the bamboo short fiber felt layer, 0 ° direction bamboo silk, bamboo silk weaving layer are sequentially arranged from top to bottom.This patent uses the reinforcing unit of bamboo short fiber felt layer, 0 ° direction bamboo silk, bamboo silk weaving layer to prepare pipeline, bamboo short fiber felt has finer fiber, fiber is more closely arranged between can solve the disadvantage that the porosity of bamboo silk is formed afterwards, meanwhile, bamboo fiber felt has stronger resin adsorption capacity.Another advantage of the present technology is that the arrangement of the fiber material, which is a non-homogeneous material, determines the orientation of the strength in the 0 ° direction. The bamboo silk can improve the axial strength of the pipeline. On the other hand, the present technology uses three or more bamboo silk for weaving, which increases the hoop strength and axial strength.

Description

Technical Field

[0001] This invention relates to the field of bamboo winding pipe technology, and in particular to a bamboo winding pipe structure and its production method. Background Technology

[0002] Bamboo is the fastest-growing plant in the world. Studies show that bamboo can grow up to 1.21 meters every 24 hours, completing both height and thickness growth in just 2-3 months. Bamboo matures quickly, forming forests in 3-5 years, and produces new shoots annually, resulting in high yields and sustainable afforestation. Bamboo is widely distributed and has considerable resources. Bamboo fiber possesses high tensile strength and toughness, making it one of the most suitable bio-based materials for pipe manufacturing. Chinese patent CN118906505A discloses a method for producing bamboo-wound pipes, including: winding a fabric impregnated with unsaturated polyester onto a mold to obtain an inner lining layer; while the unsaturated polyester is in a gel state, winding a first layer of bamboo strips around the outside of the inner lining layer; heating the inner lining layer and the first layer of bamboo strips until the unsaturated polyester solidifies; continuing to wind the bamboo strips to a predetermined number of layers to obtain a structural layer; placing the mold in a curing oven to heat and solidify the structural layer; fabricating an outer protective layer on the outside of the structural layer; and forming a bamboo-wound composite pipe from the inner lining layer, structural layer, and outer protective layer; and removing the bamboo-wound composite pipe from the mold after the outer protective layer has completely solidified. This application addresses the problem of interfacial bonding between the gel-state unsaturated polyester and urea-formaldehyde resin under high temperature, forming a cross-linked interpenetrating network structure, thus achieving a stronger interfacial bond and effectively solving the problems of interfacial bonding between the inner lining layer and the structural layer, as well as the bulging problem of the inner lining layer. However, in practical production, due to the limited height of bamboo growth, it is difficult to form continuous fibers like glass fiber or basalt fiber by mechanically crushing it into bamboo shreds or separating it. Therefore, traditional continuous winding processes for pipes cannot be used during production. Furthermore, because the separated bamboo fibers are relatively coarse, the gaps between the fibers are large during winding, and the resin cannot completely fill them, resulting in high porosity and poor strength in the pipe wall. On the other hand, due to the limitations of winding equipment, traditional winding methods cannot perform small-angle winding, meaning there are more fibers distributed circumferentially and fewer fibers distributed axially (0° direction), leading to uneven fiber distribution in the pipe and consequently poor axial strength. These technical shortcomings have limited the application of bamboo fiber pipes in many fields. Summary of the Invention

[0003] The purpose of this invention is to provide a bamboo-wound tube structure and its production method, in order to solve the defects of traditional winding processes in preparing bamboo-wound tubes, such as the inability to continuously wind, large porosity between fibers in the tube wall, and poor axial strength.

[0004] The technical solution of the present invention:

[0005] A bamboo-wound tube structure is composed of bamboo fiber reinforced material units and an adhesive. The bamboo fiber reinforced material units include a bamboo short fiber felt layer, 0° direction bamboo filaments, and a bamboo filament braided layer, which are arranged sequentially from top to bottom.

[0006] The bamboo short fiber felt layer is prepared from bamboo fibers with a diameter of 200-500μm and a length of 30-100mm by a carding machine or an airflow forming machine, and has a thickness of 3-10mm.

[0007] The 0° direction bamboo strips are bamboo strips with a width of 1-10mm, a thickness of 1-3mm, and a length of 1-6 meters, which are degreased, desugared, and softened by soaking in a 2-10% NaOH solution for 5-10 hours.

[0008] The bamboo woven layer is made of three or more bamboo filaments that have been soaked in a 2-10% NaOH solution for 5-10 hours to degrease, desugar, and soften, with a weaving angle of 30-60°.

[0009] The adhesive is an unsaturated polyester resin, epoxy resin, or polyurethane resin. During molding, a curing agent corresponding to the adhesive material is added and cured under heating conditions.

[0010] A method for producing bamboo-wound tubes includes the following steps:

[0011] S1: Bamboo fiber reinforced material unit production method: Bamboo fiber woven layer is laid at the bottom of airflow forming machine, and bamboo filaments are laid in the axial direction of the pipe with a spacing of 3-5cm. Bamboo short fibers are prepared into bamboo short fiber felt layer by a carding machine or airflow forming machine and evenly laid on bamboo filaments to form bamboo fiber reinforced material unit.

[0012] S2: Pipe winding: Spray adhesive material onto the bamboo short fiber felt layer of the bamboo fiber reinforced material unit. The amount of resin sprayed is 30-120% of the weight of the bamboo short fiber felt layer. Wrap the bamboo fiber reinforced material unit sprayed with resin onto the mandrel of the winding machine. Start the winding machine to wrap the bamboo fiber reinforced material unit onto the mandrel. Wrap one layer at a time and use a pressure roller to press the fiber so that the resin completely impregnates the bamboo fiber. Finally, wrap the polyester fiber film.

[0013] S3: Resin curing and demolding: Select the appropriate curing conditions according to the resin and curing agent used. After the resin is completely cured, remove the bamboo fiber tube from the core mold.

[0014] The thickness of the bamboo fiber felt is 3-10mm.

[0015] The width of the bamboo fiber reinforced material unit is equal to the length of the bamboo winding tube, and the length is determined based on the pipe pressure and thickness and is an integer multiple of 3.14D.

[0016] This patent uses a reinforcing unit composed of a bamboo short fiber felt layer, 0° oriented bamboo filaments, and a bamboo filament woven layer to fabricate the pipe. The bamboo short fiber felt has finer fibers and a tighter fiber arrangement, which solves the problem of high porosity after bamboo filament molding. At the same time, the bamboo fiber felt has a strong resin adsorption capacity, ensuring the resin content. The bamboo fiber felt layer is arranged inside the pipe to achieve good flatness and smoothness. Another advantage of this technology is that the fiber material is a heterogeneous material, and the fiber arrangement determines the strength orientation. The bamboo filaments are fully distributed in the 0° direction, which can improve the axial strength of the pipe. On the other hand, this technology uses three or more bamboo filaments for weaving, which increases both circumferential and axial strength. The width of the woven layer is the length of the pipe, and it is wrapped around the mandrel in one go. The number of winding layers is selected according to the pipe strength and wall thickness requirements. The bamboo filaments used are soaked in a 2-10% NaOH solution for 5-10 hours to treat them. This treatment not only degreases and removes sugars, reducing the possibility of mold growth on the bamboo fibers, but also softens the fibers, resulting in better fiber adhesion during winding and easier molding. Because this technology contains bamboo short fiber felt, which is prone to detachment, the traditional glue tank immersion method cannot be used for glue application. This technology uses a spray application method to avoid the detachment of short fibers and to precisely control the amount of glue applied. The pipes produced by integrating the above technologies have high strength and few defects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fiber distribution in the bamboo fiber wound pipe of the present invention;

[0018] Figure 2 A side view of a bamboo fiber-wound pipe. Detailed Implementation

[0019] 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 a part of the embodiments of the present invention, and not all of the 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.

[0020] This invention provides a method for producing bamboo-wound tubes, comprising the following steps:

[0021] S1: Bamboo fiber reinforced material unit production method: Bamboo fiber woven layer is laid at the bottom of airflow forming machine, and bamboo filaments are laid in the axial direction of the pipe with a spacing of 3-5cm. Bamboo short fibers are prepared into bamboo short fiber felt layer by a carding machine or airflow forming machine and evenly laid on bamboo filaments to form bamboo fiber reinforced material unit.

[0022] S2: Pipe winding: Spray adhesive material onto the bamboo short fiber felt layer of the bamboo fiber reinforced material unit. The amount of resin sprayed is 30-120% of the weight of the bamboo short fiber felt layer. Wrap the bamboo fiber reinforced material unit sprayed with resin onto the mandrel of the winding machine. Start the winding machine to wrap the bamboo fiber reinforced material unit onto the mandrel. Wrap one layer at a time and use a pressure roller to press the fiber so that the resin completely impregnates the bamboo fiber. Finally, wrap the polyester fiber film.

[0023] S3: Resin curing and demolding: Select the appropriate curing conditions according to the resin and curing agent used. After the resin is completely cured, remove the bamboo fiber tube from the core mold.

[0024] The thickness of the bamboo fiber felt is 3-10mm.

[0025] The width of the bamboo fiber reinforced material unit is equal to the length of the bamboo winding tube, and the length is determined based on the pipe pressure and thickness and is an integer multiple of 3.14D.

[0026] Example 1: DN300 bamboo fiber sewage treatment discharge pipe.

[0027] Raw materials: The resin used is epoxy resin supplied by Shanghai Huibo, and the curing agent is matched according to the type of epoxy resin.

[0028] Mixed viscosity: 300 MPa; Working time: 50 min; Curing conditions: 1 h at room temperature.

[0029] The specific steps adopt the S1 method for producing bamboo fiber reinforced material units: A bamboo fiber woven layer is laid at the bottom of the airflow forming machine, and bamboo filaments are laid in the axial direction of the pipe (0° direction), with a spacing of 3cm and a width of 3 meters. Short bamboo fibers are then processed into 3mm thick, 3-meter wide units using a carding machine. Bamboo fiber felt is evenly laid on the bamboo filaments to form bamboo fiber reinforced units with a length of 4710mm (5 units are wound). These are then set aside.

[0030] S2: Pipe winding: After mixing the resin and curing agent evenly, spray the mixture onto the bamboo felt of the bamboo fiber reinforced material unit. The amount of resin sprayed should be 50% of the fiber weight. Wrap the resin-sprayed bamboo fiber onto the mandrel of the winding machine, and start the winding machine to wrap the bamboo fiber reinforced material unit onto the mandrel. Each layer is wound using a pressure roller to press the fiber to ensure that the resin completely impregnates the bamboo fiber. Finally, a polyester fiber film is wound.

[0031] S3: Resin curing and demolding: After the resin has fully cured for 1 hour after winding, remove the bamboo fiber pipe from the core mold.

[0032] Technical specifications for bamboo-wound pipes: density 1.1 g / cm³ 3 Axial tensile strength 18MPa, ring stiffness 10000N / m2.

[0033] Example 2: DN500 anti-corrosion pipe.

[0034] Raw materials:

[0035] Resin: Modified epoxy vinyl resin; Curing agent: m-phenylenediamine

[0036] Material ratio: Epoxy vinyl resin: m-phenylenediamine = 100:10

[0037] Mixed viscosity: 400 MPa; Working time: 120 min; Curing conditions: 150℃, 1 h curing.

[0038] The specific steps adopt the S1 method for producing bamboo fiber reinforced material units: A bamboo fiber woven layer is laid at the bottom of the airflow forming machine, and 5 meters of bamboo filaments are laid in the axial direction of the pipe (0° direction), with a spacing of 5 cm and a width of 5 meters. Short bamboo fibers are then processed into 3mm thick, 5mm wide pieces using a carding machine. Bamboo fiber felt is evenly laid on the bamboo filaments to form bamboo fiber reinforced units with a length of 15700mm (10 units are wound). These are then set aside.

[0039] S2: Pipe winding: Mix epoxy vinyl ester resin and m-phenylenediamine in a 100:10 ratio until homogeneous, then spray the mixture onto the bamboo felt of the bamboo fiber reinforced material unit. The resin spraying amount should be 100% of the fiber weight. Wrap the resin-coated bamboo fibers onto the mandrel of the winding machine, and start the winding machine to wrap the bamboo fiber reinforced material unit onto the mandrel. For each layer wound, use a pressure roller to press the fibers to ensure the resin completely impregnates the bamboo fibers. Finally, wrap a polyester fiber film.

[0040] S3: Resin curing and demolding: After winding, cure at 150℃ for 1 hour. After the resin is fully cured, remove the bamboo fiber pipe from the core mold.

[0041] Technical specifications for bamboo-wound pipes: density 1.5 g / cm³ 3 Axial tensile strength 20MPa, ring stiffness ≥120000N / m2.

[0042] In addition to the preferred embodiments described above, the present invention has other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

Claims

1. A bamboo-wound tube structure, characterized in that, Composed of bamboo fiber reinforced material units and adhesive, the bamboo fiber reinforced material units include a bamboo short fiber felt layer, 0° direction bamboo filaments and a bamboo filament woven layer, which are arranged sequentially from top to bottom.

2. The bamboo winding tube structure according to claim 1, characterized in that, The bamboo short fiber felt layer is prepared from bamboo fibers with a diameter of 200-500μm and a length of 30-100mm by a carding machine or an airflow forming machine, and has a thickness of 3-10mm.

3. The bamboo winding tube structure according to claim 1, characterized in that, The 0° direction bamboo strips are bamboo strips with a width of 1-10mm, a thickness of 1-3mm, and a length of 1-6 meters, which are degreased, desugared, and softened by soaking in a 2-10% NaOH solution for 5-10 hours.

4. The bamboo winding tube structure according to claim 1, characterized in that, The bamboo woven layer is made of three or more bamboo filaments that have been soaked in 2-10% NaOH solution for 5-10 hours to degrease, desugar, and soften, with a weaving angle of 30-60°.

5. The bamboo winding tube structure according to claim 1, characterized in that, The adhesive is an unsaturated polyester resin, epoxy resin, or polyurethane resin. During molding, a curing agent corresponding to the adhesive material is added and cured under heating conditions.

6. A method for producing a bamboo winding tube as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Bamboo fiber reinforced material unit production method: Bamboo fiber woven layer is laid at the bottom of airflow forming machine, and bamboo filaments are laid in the axial direction of the pipe with a spacing of 3-5cm. Bamboo short fibers are prepared into bamboo short fiber felt layer by a carding machine or airflow forming machine and evenly laid on bamboo filaments to form bamboo fiber reinforced material unit. S2: Pipe winding: Spray adhesive material onto the bamboo short fiber felt layer of the bamboo fiber reinforced material unit. The amount of resin sprayed is 30-120% of the weight of the bamboo short fiber felt layer. Wrap the bamboo fiber reinforced material unit sprayed with resin onto the mandrel of the winding machine. Start the winding machine to wrap the bamboo fiber reinforced material unit onto the mandrel. Wrap one layer at a time and use a pressure roller to press the fiber so that the resin completely impregnates the bamboo fiber. Finally, wrap the polyester fiber film. S3: Resin curing and demolding: Select the appropriate curing conditions according to the resin and curing agent used. After the resin is completely cured, remove the bamboo fiber tube from the core mold.

7. The method for producing bamboo-wound tubes according to claim 6, characterized in that, The thickness of the bamboo fiber felt is 3-10mm.

8. The method for producing bamboo-wound tubes according to claim 6, characterized in that, The width of the bamboo fiber reinforced material unit is equal to the length of the bamboo winding tube, and the length is determined based on the pipe pressure and thickness and is an integer multiple of 3.14D.

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