A high strength composite fiber preparation and setting process for Christmas tree branches

Abstract

The application discloses a high-strength composite fiber preparation and setting process for Christmas tree branches, relates to the technical field of composite fiber material and decorative product processing, and improves the structural strength and stability of the Christmas tree branches by optimizing the composite fiber material formula and the preparation process and combining with the sectional gradient temperature control setting technology, so that the root tensile strength reaches above 950 MPa, and the load bearing requirement of large-sized Christmas trees is met. Meanwhile, the flexible setting and low-temperature treatment process makes the bending angle of the tip part reach 90 DEG without breaking, greatly enhances the modeling plasticity and simulation degree, and verifies the durability of the product under different climate conditions through the environmental adaptability test, and realizes the comprehensive improvement of the strength, toughness and aesthetic appearance.

Description

Technical Field

[0001] This invention relates to the field of composite fiber materials and decorative product processing technology, specifically to a high-strength composite fiber preparation and shaping process for Christmas tree branches. Background Technology

[0002] As the Christmas decoration market continues to expand, consumers are increasingly demanding higher quality Christmas trees and their accessories. As a core element of holiday decorations, the strength, resilience, and aesthetics of the branches of a Christmas tree directly affect the overall decorative effect and safety. Traditional Christmas tree branches are mostly made of plastic or metal, materials that have limitations in terms of strength, weight, environmental friendliness, and sculptural flexibility.

[0003] Traditional Christmas tree branch manufacturing techniques suffer from several shortcomings: First, in terms of material selection, plastic branches have low strength, are easily deformed, and cannot support heavy decorations; while metal branches, although strong enough, are heavy, difficult to transport and install, and costly. Second, in terms of manufacturing processes, traditional methods struggle to precisely control the mechanical properties and surface quality of branches, resulting in poor product consistency and difficulty in meeting high-precision customization requirements. Furthermore, traditional branches have limited sculpting flexibility, failing to simulate the natural shape and flexibility of real tree branches, thus affecting the overall aesthetics and realism of the Christmas tree. Finally, regarding environmental adaptability, traditional materials exhibit poor stability and durability under different climatic conditions, making it difficult to meet the needs of outdoor and extreme environments. Therefore, this invention proposes a high-strength composite fiber preparation and shaping process for Christmas tree branches, addressing the problems of insufficient strength, poor toughness, limited sculpting flexibility, and poor environmental adaptability inherent in traditional Christmas tree branch manufacturing techniques. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-strength composite fiber preparation and shaping process for Christmas tree branches. By optimizing the composite fiber material formulation and preparation process, combined with segmented gradient temperature-controlled shaping technology, the structural strength and stability of the Christmas tree branches are improved, with a root tensile strength of over 950 MPa, meeting the load-bearing requirements of large Christmas trees. At the same time, through flexible shaping and low-temperature treatment processes, the tip can be bent at an angle of up to 90° without breaking, greatly enhancing the plasticity and realism of the shape. Furthermore, environmental adaptability tests have verified the product's durability under different climatic conditions, achieving a comprehensive improvement in strength, toughness, and aesthetics.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a process for preparing and shaping high-strength composite fibers for Christmas tree branches, the specific steps of which are as follows: Composite fiber preparation: using basalt fiber and modified polypropylene as the matrix, in-situ interface modification is carried out by a specific ratio of silane coupling agent, and melt blending and spinning processes are adopted to control the spinning speed and draw ratio to prepare composite fiber precursors with specific mechanical properties and surface roughness. Preforming and stress control: The composite fiber filaments are pre-bent using segmented special rollers. The pre-tension stress is monitored and controlled in real time by a tension sensor to eliminate residual stress inside the fiber and ensure the stability of the branching shape during the subsequent setting process. Segmented gradient temperature-controlled shaping: Three-stage shaping treatment is applied to composite fibers. The root is shaped under high temperature and high pressure using a high-pressure hot pressing mold that matches the shape of the branch. After shaping, it is held under pressure and cooled to ensure high strength support performance. The middle section employs a gradient cooling temperature control curve and auxiliary cooling method to achieve a uniform transition in crystallinity, balancing strength and toughness. The tip is gently shaped using a flexible molding die to control fiber crystallinity and improve flexibility and shapeability. Post-processing and quality inspection: After shaping, a segmented cooling method is adopted, with air cooling at the root and natural cooling at the tip, and cooling parameters are controlled to avoid dimensional deviations and residual internal stress; online tension regulation is carried out through a closed-loop control algorithm, and dimensional accuracy and shape consistency are detected by three-dimensional laser scanning; and environmental adaptability tests such as high-temperature softening, low-temperature embrittlement and ultraviolet aging are carried out to verify the stability and durability of the product.

[0006] Furthermore, in the composite fiber preparation step, the mass ratio of basalt fiber to modified polypropylene is 3:7, the silane coupling agent is γ-aminopropyltriethoxysilane, where γ- represents gamma, and the addition amount is 0.5% of the total mass of the matrix; the melt blending temperature is 210℃, the spinning speed is 120m / min, the draw ratio is 3.5, and the diameter of the prepared composite fiber precursor is 0.8mm, the tensile strength is ≥800MPa, the elongation at break is ≥25%, and the surface roughness Ra≤0.2μm. This can effectively improve the fit between the fiber and the mold during the subsequent shaping process and avoid delamination or cracking caused by insufficient interfacial bonding.

[0007] Furthermore, in the preforming and stress control steps, the special rollers adopt a segmented structure, with a root roller diameter of 120mm, a middle roller diameter of 80mm, and a tip roller diameter of 40mm. The roller surface is covered with a silicone layer to prevent fiber scratches. The pre-tension stress is monitored in real time by a tension sensor and controlled at 10-15% of the fiber breaking strength. The pre-bending forming angle is 15-20°, and the pre-bending speed is 5m / min. This eliminates residual stress inside the fiber, ensures stable branching morphology during subsequent shaping, and avoids twisting or springback.

[0008] Furthermore, in the segmented gradient temperature-controlled shaping step, the root shaping step uses a high-pressure hot-pressing mold made of stainless steel, with an internal electric heating tube and temperature sensor. The mold cavity perfectly matches the shape of the branch root, and the cavity surface is polished to Ra≤0.1μm. The shaping temperature is 190℃, the pressure is 1.0MPa, the holding time is 12s, and after the holding time, a 0.5MPa pressure is applied for 3s of cooling. This effectively improves the crystallinity and structural density of the fiber, increasing the tensile strength of the root to over 950MPa, meeting the load-bearing requirements of large Christmas tree branches, while avoiding stress concentration caused by excessively rapid cooling.

[0009] Furthermore, in the segmented gradient temperature control and shaping step, the intermediate transition shaping step adopts a gradient cooling temperature control curve, reducing the temperature from 170℃ to 150℃ at a rate of 5℃ / s, with a holding time of 10s. During the cooling process, a fan is used for auxiliary cooling at a wind speed of 1.5m / s to ensure a uniform transition in the crystallinity of the fiber and avoid sudden performance changes due to a rapid temperature drop. The fiber breaking elongation after intermediate shaping is controlled at 30-35%, which can effectively balance strength and toughness, so that the branches can maintain structural stability when subjected to external forces, while also generating a certain deformation buffer, thereby improving the overall service life.

[0010] Furthermore, in the segmented gradient temperature-controlled shaping step, the tip shaping step employs a flexible shaping mold made of silicone rubber with a Shore hardness of 60A, which is adaptively adjusted according to the natural curvature of the branch tip. The shaping temperature is 130℃, the holding time is 6s, and after the holding time, the material is naturally cooled to room temperature, reducing the crystallinity of the tip fiber to below 25%, increasing the elongation at break to above 40%, and allowing the bending angle to reach 90° without breakage. This effectively simulates the flexibility of real tree branches, enhancing the simulation and shape plasticity of the Christmas tree.

[0011] Furthermore, in the post-processing and quality inspection steps, the segmented cooling adopts root air cooling and tip natural cooling. The root air cooling wind speed is 2.0m / s, the cooling time is 15s, and the temperature is cooled to below 40℃. The tip natural cooling environment temperature is 25℃, the relative humidity is 50%, and the cooling time is 30s. This can effectively avoid dimensional deviations or residual internal stress caused by uneven cooling rates. The straightness deviation of the cooled branches is ≤0.5mm, and the shape retention rate is ≥98%, which can meet the customized needs of high-precision irregular Christmas tree branches.

[0012] Furthermore, in the post-processing and quality inspection steps, the online tension control adopts a closed-loop control algorithm. The tension sensor collects fiber tension data in real time, compares it with the preset value, and automatically adjusts the roller speed to ensure that the tension fluctuation range is ≤±2%. The laser scanning inspection uses a three-dimensional laser scanner with a scanning accuracy of 0.01mm and a scanning frequency of 10Hz. It detects the curvature, length, and thickness parameters of the branches in real time, compares them with the design values, and automatically marks unqualified products to ensure the consistency and stability of mass production and improve the product qualification rate to over 99.5%.

[0013] Furthermore, the environmental adaptability test in the post-processing and quality inspection steps includes a high-temperature softening test and a low-temperature embrittlement test. The high-temperature softening test conditions are 60℃ for 24 hours, and the branch deformation after the test is ≤0.5mm, with no softening or sagging. The low-temperature embrittlement test conditions are -20℃ for 4 hours, and the branch can be bent at 30° without breakage or cracking after the test. At the same time, an ultraviolet aging test is performed under the conditions of UVB 313nm for 1000 hours, and the mechanical property retention rate after the test is ≥90%. This can effectively verify the stability and durability of the branch under different environments and meet the usage requirements in outdoor and extreme environments.

[0014] Compared with existing technologies, this high-strength composite fiber preparation and shaping process for Christmas tree branches has the following advantages: I. This invention utilizes basalt fiber and modified polypropylene in a 3:7 mass ratio as the matrix, combined with 0.5% γ-aminopropyltriethoxysilane by mass for in-situ interfacial modification. This, combined with a spinning process of 210℃ melt blending, 120m / min spinning speed, and a 3.5 times draw ratio, overcomes the technical bottlenecks of traditional plastic branches (low strength, easy deformation) and metal branches (large weight, high cost). The prepared composite fiber precursor has a tensile strength ≥800MPa and an elongation at break ≥25%, achieving lightweight while laying a material foundation for Christmas tree branches that balances high strength and high toughness. Simultaneously, by precisely controlling the fiber surface roughness Ra≤0.2μm, the adhesion between the fiber and the mold during subsequent shaping is effectively improved, avoiding delamination and cracking problems caused by insufficient interfacial bonding.

[0015] II. This invention employs a segmented pre-bending forming process combined with real-time tension control using specialized rollers. This, along with a three-stage gradient temperature control forming technology that differentiates the root, middle, and tip sections, solves the industry pain points of traditional manufacturing processes, such as inability to meet the performance requirements of different parts of the branch, poor shape consistency, and susceptibility to springback deformation. Specifically, the root section undergoes high-temperature, high-pressure forming at 190℃ and 1.0MPa, combined with a pressure-holding cooling process, increasing the tensile strength of the branch root to over 950MPa, fully meeting the load-bearing requirements of large Christmas trees. The middle section undergoes high-temperature, high-pressure forming at 170℃ to 150MPa... The 0℃ gradient cooling temperature control process achieves a uniform transition in fiber crystallinity, stabilizing the elongation at break at 30-35%, perfectly balancing support and deformation buffering capacity. The tip is softened and shaped using a 130℃ silicone rubber flexible mold, controlling the fiber crystallinity at the tip to below 25% and increasing the elongation at break to over 40%, enabling 90° bending without breakage. This significantly enhances the plasticity and natural simulation of the branch shape, fundamentally achieving differentiated performance customization of the Christmas tree branch with high strength at the root, a combination of strength and toughness in the middle, and high flexibility at the tip.

[0016] Third, this invention utilizes a segmented post-processing cooling technology—root air cooling and tip natural cooling—combined with closed-loop online tension control, three-dimensional laser scanning for full-size inspection, and comprehensive environmental adaptability testing including high-temperature softening, low-temperature embrittlement, and UV aging. This effectively eliminates residual internal stress during product processing, controls branch straightness deviation to ≤0.5mm, maintains a shape retention rate of ≥98%, and increases the batch production qualification rate to over 99.5%. Simultaneously, it verifies the product's stability in extreme environments ranging from -20℃ to 60℃ and under long-term outdoor UV radiation, with a mechanical property retention rate of ≥90%. This significantly improves the durability of Christmas tree branches under different climatic conditions, ultimately achieving a comprehensive improvement in product strength, toughness, simulation accuracy, and environmental adaptability.

[0017] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1This is a flowchart illustrating the core process of preparing and shaping a high-strength composite fiber for Christmas tree branches. Figure 2 A process flow diagram showing the specific parameters for the preparation and shaping of a high-strength composite fiber for Christmas tree branches; Figure 3 This is a flowchart illustrating the specific process flow of root shaping in the segmented gradient temperature-controlled shaping process for the preparation and shaping of high-strength composite fibers used in Christmas tree branches. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] Example 1 This embodiment follows the following... Figure 1 The overall preparation and shaping core process flow shown is as follows: In this embodiment, the composite fiber is prepared by mixing basalt fiber and modified polypropylene as the matrix in a 3:7 mass ratio. This ratio balances the high strength of basalt fiber with the good formability of modified polypropylene, laying a solid foundation for the excellent mechanical properties of the composite fiber. γ-aminopropyltriethoxysilane is selected as the silane coupling agent, and it is added to the matrix at a mass of 0.5% of the total matrix mass for in-situ interface modification. This coupling agent effectively improves the interfacial bonding force between basalt fiber and modified polypropylene, avoiding matrix delamination and fiber debonding during subsequent processing, and enhancing the overall structural stability of the composite fiber. Subsequently, melt blending and spinning processes are used for processing. The melt blending temperature is set at 210℃, which allows the modified polypropylene to... The process ensures complete melting without thermal degradation of basalt fibers, guaranteeing uniform matrix mixing. Simultaneously, precise control of the spinning speed (120 m / min) and draw ratio (3.5) allows for the regulation of fiber molecular orientation, further enhancing tensile strength and elongation at break. This results in a composite fiber precursor with a diameter of 0.8 mm, achieving tensile strength ≥800 MPa, elongation at break ≥25%, and surface roughness Ra ≤0.2 μm. The suitable surface roughness improves adhesion to the molding die, preventing interfacial bubbles during molding. The entire preparation process, through precise control of raw material ratios and process parameters, ensures the composite fiber precursor possesses the high strength, good toughness, and suitable surface properties required for Christmas tree branches, laying a high-quality material foundation for subsequent preforming and molding processes. Figure 2 As shown.

[0022] Preforming and Stress Control: The prepared composite fiber filaments are pre-bent using segmented specialized rollers. These rollers are designed with a segmented structure to meet the gradual branching requirements of a Christmas tree. The diameter of the root roller is set to 120mm, the middle roller to 80mm, and the tip roller to 40mm, allowing the fiber to form a natural, gradual bending shape from root to tip. The roller surface is coated with a silicone layer, which effectively prevents scratches on the fiber surface during pre-bending, protects the structural integrity of the fiber, and reduces frictional damage between the fiber and the roller. The pre-tension stress of the fiber is monitored in real time using a tension sensor. The stress is precisely controlled within 10-15% of the fiber breaking strength. This stress range effectively eliminates the internal residual stress generated during melt blending and spinning, while preventing fiber breakage due to excessive stress. At the same time, the pre-bending angle is set at 15-20° and the pre-bending speed is 5m / min. Reasonable pre-bending parameters allow the fiber to form an initial bending shape that fits the Christmas tree branches, effectively avoiding problems such as shape deviation and springback during subsequent shaping. This ensures the stability of the Christmas tree branch shape and provides a well-shaped semi-finished product for the subsequent segmented gradient temperature-controlled shaping process, ensuring the consistency of the final product's shape.

[0023] Segmented gradient temperature control shaping: The pre-formed composite fiber is subjected to a three-stage shaping process. By selecting different molds and adjusting process parameters, the performance of different parts of the Christmas tree branch is differentiated, which precisely matches the usage requirements of high-strength support at the root, strength and toughness in the middle, and high plasticity at the tip, so that the mechanical and shaping properties of the finished branch are highly adapted to the use scenarios of the Christmas tree. The root section is shaped under high temperature and pressure using a stainless steel high-pressure hot-press mold that perfectly matches the shape of the branch root. The mold is equipped with an electric heating element and a temperature sensor, enabling precise control and uniform heating of the shaping temperature. The precise match between the mold cavity and the branch root shape allows the fiber root to fully conform to the mold. The cavity surface is polished to Ra≤0.1μm to further improve the fit and reduce interface bubbles during the shaping process. During shaping, the temperature is controlled at 190℃, the pressure at 1.0MPa, and the holding time at 12s. These parameters allow the fiber root to fully plasticize and form a dense structure, ensuring the high-strength support performance of the branch root and meeting the requirements of the Christmas tree branch root to withstand the overall branch weight and decorative load. After the holding time, a pressure of 0.5MPa is applied for 3s of pressure cooling. This pressure cooling effectively fixes the shaped form of the fiber root, preventing deformation due to stress release during cooling and further strengthening the structural stability of the root. Figure 3As shown; the middle section employs a gradient cooling temperature control curve combined with auxiliary cooling for shaping. Following the gradient cooling temperature control curve, the temperature is reduced from 170℃ to 150℃ at a rate of 5℃ / s and held for 10 seconds. During the cooling process, a fan provides auxiliary cooling at a wind speed of 1.5m / s. The gradient cooling method ensures a uniform transition in the crystallinity of the fiber's middle section, avoiding mechanical property deviations caused by uneven crystallinity due to sudden temperature changes. Auxiliary cooling precisely controls the crystallization process, keeping the fiber's elongation at break after shaping at 30-35%, achieving a balance between strength and toughness. This meets the requirements of the Christmas tree branch, which connects the root and tip, needing both support and good flexibility. The tip section uses fibers with a Shore hardness of 60A. A flexible silicone rubber molding die is used for low-temperature gentle shaping. This flexible molding die can adaptively adjust according to the natural curvature of the branch tip, better conforming to the bending shape of the tip and avoiding damage to the tip shape caused by a rigid die. The shaping temperature is set at 130℃ and the holding time is 6 seconds. These low-temperature shaping parameters can precisely control the crystallization process of the fiber tip, reducing the crystallinity of the fiber tip to below 25% and increasing the elongation at break to above 40%. After the holding time, the fiber tip is naturally cooled to room temperature to further ensure precise control of the crystallinity of the tip. This allows the tip to bend at an angle of up to 90° without breaking, effectively improving the flexibility and plasticity of the tip, and meeting the needs of Christmas tree branch tips for flexible shaping and adaptation to different decorative layouts.

[0024] Post-processing and quality inspection: After shaping, the composite fibers undergo segmented cooling for post-processing. Simultaneously, a closed-loop control algorithm enables online tension regulation. Combined with high-precision detection and comprehensive environmental adaptability testing, this ensures the final product's dimensional accuracy, shape consistency, and environmental tolerance, guaranteeing that the prepared Christmas tree branch composite fibers can adapt to different usage environments and meet long-term use requirements. A segmented cooling method is employed: root air cooling and tip natural cooling. The root air cooling speed is set at 2.0 m / s, with a cooling time of 15 seconds, cooling the root to below 40℃. Rapid air cooling quickly fixes the root's shape, further improving its dimensional stability. The tip is naturally cooled for 30 seconds at an ambient temperature of 25℃ and relative humidity of 50%. Slow natural cooling avoids internal stress caused by sudden temperature drops, protecting the tip's high plasticity. The entire segmented cooling process, through precise control of cooling parameters, effectively prevents dimensional deviations and residual internal stress in the fibers, ensuring that the straightness deviation of the cooled Christmas tree branch is ≤0.5. mm, shape retention rate ≥98%; the online tension control process adopts a closed-loop control algorithm, which collects fiber tension data in real time through tension sensors, compares the collected data with preset values, and automatically adjusts the roller speed based on the comparison results to ensure that the tension fluctuation range is ≤±2%. The application of the closed-loop control algorithm realizes real-time dynamic tension control, ensuring uniform fiber stress during subsequent processing, and further improving the size and shape consistency of the product; a 3D laser scanner is used to perform laser scanning inspection on the branches, detecting the curvature, length, and thickness parameters of the branches in real time, and comparing the inspection results with the design values ​​to automatically mark unqualified products. The scanning inspection system boasts high precision and efficiency, accurately identifying dimensional deviations and shape defects in products, enabling rapid screening of defective products and improving the overall yield rate. Finally, environmental adaptability tests are conducted, including high-temperature softening, low-temperature embrittlement, and UV aging tests. The high-temperature softening test is performed at 60℃ for 24 hours, requiring branch deformation ≤0.5mm and no softening or sagging afterward. This test verifies the structural stability of the product under high-temperature conditions, preventing branch deformation of the Christmas tree in high-temperature environments. The low-temperature embrittlement test is performed at -20℃ for 4 hours, requiring the branches to be bent... The product exhibits no breakage or cracking when folded at 30°, verifying its toughness in low-temperature environments and preventing branch breakage in cold conditions. The UV aging test, conducted for 1000 hours under UVB 313nm conditions (UVB refers to the UVB band), requires a mechanical property retention rate of ≥90% after testing. This test verifies the product's anti-aging ability under outdoor UV radiation, extending the lifespan of the Christmas tree branches. Through comprehensive environmental adaptability testing, the product's stability and durability are fully verified, ensuring that the prepared Christmas tree branch composite fiber can adapt to different indoor and outdoor usage environments and long-term use requirements.

[0025] Example 2 This embodiment also follows the same principle. Figure 1 The core process flow shown is as follows, with specific parameters and implementation procedures: In this embodiment, composite fiber preparation: basalt fiber and modified polypropylene are selected as matrix raw materials and mixed strictly according to a 3:7 mass ratio. γ-aminopropyltriethoxysilane is added as a silane coupling agent at a ratio of 0.5% of the total matrix mass for in-situ interface modification. Melt blending and spinning processes are used, with a melt blending temperature of 210℃, a spinning speed of 120m / min, and a draw ratio of 3.5, to prepare composite fiber precursors with a diameter of 0.8mm. Testing shows that the precursor has a tensile strength of 810MPa, an elongation at break of 26%, and a surface roughness Ra of 0.19μm, meeting the performance requirements of tensile strength ≥800MPa, elongation at break ≥25%, and surface roughness Ra ≤0.2μm. Figure 2 As shown.

[0026] Pre-forming and stress control: The composite fiber filaments are pre-bent using segmented special rollers. The rollers have a root diameter of 120mm, a middle diameter of 80mm, and a tip diameter of 40mm, and are covered with a silicone layer to prevent fiber scratches. The pre-tension stress is monitored and controlled in real time using a tension sensor. In this implementation, it is controlled at 12% of the fiber breaking strength. At the same time, the pre-bending angle is set to 18° and the pre-bending speed is 5m / min. By setting these parameters, residual stress inside the fiber is fully eliminated, ensuring that the Christmas tree branch shape does not shift or deform during subsequent shaping.

[0027] Segmented gradient temperature-controlled shaping: The pre-formed composite fibers undergo three-segment gradient temperature-controlled shaping. A stainless steel high-pressure hot-press mold matching the shape of the branch root is used at the root. The mold cavity is polished to Ra≤0.1μm and includes an internal electric heating element and temperature sensor. The shaping parameters are set to 190℃ and 1.0MPa, followed by holding at 12s and then cooling at 0.5MPa for 3s to ensure excellent high-strength support performance at the branch root. Figure 3 As shown; the middle section adopts a gradient cooling temperature control curve, reducing the temperature from 170℃ to 150℃ at a rate of 5℃ / s, and holding it at that temperature for 10s. At the same time, the fan is turned on to assist cooling at a wind speed of 1.5m / s, achieving a uniform transition in crystallinity. After shaping, the elongation at break of the middle fiber is 32%, balancing strength and toughness. The tip uses a flexible shaping mold made of silicone rubber with a Shore hardness of 60A, which is adaptively adjusted to fit the natural curvature of the branch tip. It is held at 130℃ for 6s, and then naturally cooled to room temperature, reducing the crystallinity of the tip fiber to 23% and increasing the elongation at break to 42%. It can bend 90° without breaking, exhibiting good flexibility and shape plasticity.

[0028] Post-processing and quality inspection: After shaping, a segmented cooling post-processing was implemented. The root was air-cooled at a wind speed of 2.0 m / s for 15 seconds to reach 38°C, while the tip was naturally cooled in an environment of 25°C and 50% relative humidity for 30 seconds. After testing, the straightness deviation of the Christmas tree branches after cooling was 0.4 mm, the shape retention rate was 98.5%, and there were no dimensional deviations or residual internal stress issues. Online tension control adopted a closed-loop control algorithm, which collected data in real time through tension sensors and compared it with preset values ​​to automatically adjust the roller speed. In this implementation, the tension fluctuation range was controlled within ±1. 5%; The curvature, length, and thickness of the branches were detected using a 3D laser scanner, and the results were precisely matched with the design values, with no unqualified product markings; Environmental adaptability tests were conducted, and after a high-temperature softening test at 60℃ for 24 hours, the branch deformation was 0.4mm, with no softening or sagging; after a low-temperature embrittlement test at -20℃ for 4 hours, the branch did not break or crack when bent at 30°; after a UVB 313nm ultraviolet aging test for 1000 hours, the product's mechanical properties retention rate was 91%, and all test results met the standards, verifying the product's stability and durability.

[0029] Understandably, this invention provides a high-strength composite fiber preparation and shaping process for Christmas tree branches. By optimizing the composite fiber material formulation and preparation process, combined with segmented gradient temperature-controlled shaping technology, the structural strength and stability of the Christmas tree branches are improved, with a root tensile strength exceeding 950 MPa, meeting the load-bearing requirements of large Christmas trees. Simultaneously, through flexible shaping and low-temperature treatment processes, the tip can be bent at an angle of up to 90° without breaking, significantly enhancing the plasticity and realism of the shape. Furthermore, environmental adaptability tests have verified the product's durability under different climatic conditions, achieving a comprehensive improvement in strength, toughness, and aesthetics, and demonstrating high reliability.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for preparing and shaping high-strength composite fibers for Christmas tree branches, characterized in that, The specific steps of this process are as follows: Composite fiber preparation: using basalt fiber and modified polypropylene as the matrix, in-situ interface modification is carried out by a specific ratio of silane coupling agent, and melt blending and spinning processes are adopted to control the spinning speed and draw ratio to prepare composite fiber precursors with specific mechanical properties and surface roughness. Preforming and stress control: The composite fiber filaments are pre-bent using segmented special rollers. The pre-tension stress is monitored and controlled in real time by a tension sensor to eliminate residual stress inside the fiber and ensure the stability of the branching shape during the subsequent setting process. Segmented gradient temperature-controlled shaping: Three-stage shaping treatment is applied to composite fibers. The root is shaped under high temperature and high pressure using a high-pressure hot pressing mold that matches the shape of the branch. After shaping, it is held under pressure and cooled to ensure high strength support performance. The middle section employs a gradient cooling temperature control curve and auxiliary cooling method to achieve a uniform transition in crystallinity, balancing strength and toughness. The tip is gently shaped using a flexible molding die to control fiber crystallinity and improve flexibility and shapeability. Post-processing and quality inspection: After shaping, a segmented cooling method is adopted, with air cooling at the root and natural cooling at the tip, and cooling parameters are controlled to avoid dimensional deviations and residual internal stress; online tension regulation is carried out through a closed-loop control algorithm, and dimensional accuracy and shape consistency are detected by three-dimensional laser scanning; and high-temperature softening, low-temperature embrittlement and UV aging environmental adaptability tests are carried out to verify the product's stability and durability.

2. The high-strength composite fiber preparation and shaping process for Christmas tree branches according to claim 1, characterized in that, In the composite fiber preparation step, the mass ratio of basalt fiber to modified polypropylene is 3:7, the silane coupling agent is γ-aminopropyltriethoxysilane, and the addition amount is 0.5% of the total mass of the matrix; the melt blending temperature is 210℃, the spinning speed is 120m / min, the draw ratio is 3.5, the diameter of the prepared composite fiber precursor is 0.8mm, the tensile strength is ≥800MPa, the elongation at break is ≥25%, and the surface roughness Ra≤0.2μm.

3. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the preforming and stress control steps, the special rollers adopt a segmented structure, with a root roller diameter of 120mm, a middle roller diameter of 80mm, and a tip roller diameter of 40mm. The roller surface is covered with a silicone layer to avoid fiber scratches. The pre-tension stress is monitored in real time by a tension sensor and controlled at 10-15% of the fiber breaking strength. The pre-bending angle is 15-20°, and the pre-bending speed is 5m / min to eliminate residual stress inside the fiber.

4. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the segmented gradient temperature control shaping step, the root shaping step uses a high-pressure hot press mold made of stainless steel, with an internal electric heating tube and temperature sensor. The mold cavity perfectly matches the shape of the branch root, and the cavity surface is polished to Ra≤0.1μm. The shaping temperature is 190℃, the pressure is 1.0MPa, the holding time is 12s, and after the holding time is completed, a 0.5MPa pressure is applied for 3s of cooling.

5. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the segmented gradient temperature control and shaping step, the intermediate transition shaping step adopts a gradient cooling temperature control curve, reducing the temperature from 170℃ to 150℃ at a rate of 5℃ / s, with a holding time of 10s. During the cooling process, a fan is used for auxiliary cooling at a wind speed of 1.5m / s. The fiber breaking elongation after intermediate shaping is controlled at 30-35%.

6. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the segmented gradient temperature-controlled shaping step, the tip shaping step uses a flexible shaping mold made of silicone rubber with a Shore hardness of 60A, which is adaptively adjusted according to the natural curvature of the branch tip. The shaping temperature is 130℃, the holding time is 6s, and after the holding time is completed, it is naturally cooled to room temperature, which reduces the crystallinity of the tip fiber to below 25%, increases the elongation at break to above 40%, and allows the bending angle to reach 90° without breaking.

7. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the post-processing and quality inspection steps, the segmented cooling adopts root air cooling and tip natural cooling. The root air cooling wind speed is 2.0m / s, the cooling time is 15s, and the temperature is cooled to below 40℃. The tip natural cooling environment temperature is 25℃, the relative humidity is 50%, and the cooling time is 30s. The straightness deviation of the branches after cooling is ≤0.5mm, and the shape retention rate is ≥98%.

8. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, In the post-processing and quality inspection steps, the online tension control adopts a closed-loop control algorithm. The tension sensor collects fiber tension data in real time, compares it with the preset value, and automatically adjusts the roller speed to ensure that the tension fluctuation range is ≤±2%. The laser scanning inspection uses a three-dimensional laser scanner to detect the curvature, length, and thickness parameters of the branches in real time, compares them with the design value, and automatically marks unqualified products.

9. The process for preparing and shaping high-strength composite fibers for Christmas tree branches according to claim 1, characterized in that, The environmental adaptability test in the post-processing and quality inspection steps includes a high-temperature softening test and a low-temperature embrittlement test. The high-temperature softening test conditions are 60℃ for 24 hours, and the branch deformation after the test is ≤0.5mm with no softening or sagging. The low-temperature embrittlement test conditions are -20℃ for 4 hours, and the branch can be bent at 30° without breakage or cracking after the test. At the same time, an ultraviolet aging test is performed under the conditions of UVB 313nm for 1000 hours, and the mechanical property retention rate after the test is ≥90%.

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