HDPE high wear-resistant monofilament, its preparation method and application

Abstract

The application belongs to the technical field of polyethylene monofilament preparation, and discloses a kind of HDPE high wear-resistant monofilament.The monofilament has three-dimensional network structure formed by silane hydrolysis crosslinking, and the preparation raw materials include, by weight, 100 parts of silane grafted HDPE masterbatch, 0.5-2.0 parts of composite catalyst, 0.2-0.6 parts of wear-resistant synergist and 0.1-0.4 parts of antioxidant.The preparation raw materials of the silane grafted HDPE masterbatch include 100 parts of HDPE resin, 3-8 parts of modified silane monomer, 0.2-0.8 parts of composite initiator, 0.1-0.5 parts of hydrolysis inhibitor and 0.3-0.9 parts of dispersant.Modified silane monomer is compounded by vinyl trimethoxysilane and gamma-methacryloyloxypropyl trimethoxysilane;Composite initiator is compounded by dicumyl peroxide and benzoyl peroxide;Composite catalyst is compounded by dibutyltin dilaurate and stannous octoate;Wear-resistant synergist is compounded by nano-silicon dioxide and polytetrafluoroethylene micro powder.

Description

Technical Field

[0001] This invention belongs to the field of polyethylene monofilament preparation technology, and particularly relates to a high abrasion-resistant HDPE monofilament, its preparation method, and its application. Background Technology

[0002] High-density polyethylene (HDPE) possesses characteristics such as high crystallinity, good mechanical strength, and excellent processing performance. Its extruded monofilaments are widely used in protective sleeves in the automotive and aerospace industries. However, conventional HDPE monofilaments are prone to surface wear and breakage under long-term friction and complex environmental stress. To improve the wear resistance of the monofilaments, existing technologies often use ultra-high molecular weight polyethylene (UHMWPE) materials for preparation. However, this material has extremely high melt viscosity, making it impossible to obtain high-strength monofilaments through conventional melt extrusion molding. The commonly used gel spinning process is cumbersome and often requires the introduction of organic solvents, leading to a significant increase in costs and serious environmental pollution risks. In addition, directly blending a single wear-resistant filler into the resin matrix is ​​also a common modification method. However, the filler has poor compatibility with the matrix and is prone to agglomeration. In continuous extrusion of fine-diameter monofilaments, this can lead to severe surface granulation and frequent filament breakage, often at the cost of sacrificing the tensile strength and flexibility of the material itself. On the other hand, post-modification processes such as surface coating face technical bottlenecks such as weak adhesion between the coating and the matrix, easy peeling and failure under long-term friction conditions, and lengthy production processes.

[0003] To overcome the inherent defects of blending modification and surface treatment, some existing technologies enhance the overall performance of monofilaments by designing multilayer coating structures or introducing chemical crosslinking networks. The spinning process of multilayer core-shell structures involves multiple complex steps such as emulsion polymerization and co-extrusion, making it difficult to achieve efficient large-scale production. While chemical crosslinking, especially the two-step silane crosslinking method, can improve crosslinking uniformity to some extent, it still faces many technical obstacles in its practical application to the preparation of high-density polyethylene monofilaments. In the grafting reaction stage, conventional silane monomers are prone to volatilization and hydrolysis side reactions in a high-temperature melting environment, resulting in a low and drastically fluctuating final grafting rate. Simultaneously, the amount of a single initiator is difficult to precisely balance, easily leading to severe degradation of the polymer backbone or a lack of grafting active sites. In the crosslinking and molding stages, uneven catalyst dispersion leads to a severe imbalance in the crosslinking density of micro-regions, easily causing localized over-crosslinking leading to embrittlement and fracture or insufficient crosslinking. More seriously, existing crosslinking process parameters often deviate from the kinetic requirements of monofilament extrusion and stretching. The one-sided pursuit of increasing the degree of crosslinking completely destroys the synergy between the crosslinking network structure and the polymer chain orientation process, ultimately resulting in rough surfaces of extruded monofilaments, huge tolerances in wire diameter, and a sharp decrease in the toughness of the material, or even the complete loss of basic spinning continuity.

[0004] Faced with these numerous challenges, there is an urgent need to find a new approach that can fundamentally break the antagonistic relationship between high wear resistance and excellent mechanical toughness at the molecular structure level. Practical engineering applications require fundamentally suppressing the volatilization and early hydrolysis of crosslinking reaction precursors without requiring large-scale modifications to existing conventional extrusion spinning equipment, thereby obtaining a high and stable grafting rate and a dense, uniform three-dimensional crosslinked network. Based on this, further technical requirements focus on how to couple the chemical reaction kinetics process with the physical morphological evolution processes such as monofilament melt spinning, high-ratio stretching, and heat setting, thereby eliminating microscopic phase separation and localized stress concentration, and ensuring high fluidity and surface smoothness of fine-diameter monofilaments in continuous processing environments. Solving the technical challenge of synergistic adaptation between the aforementioned material modification formulation system and molding process parameters, and achieving a significant reduction in surface friction loss of polyethylene monofilaments while maintaining or even improving their tensile strength and elongation at break, thus meeting the stringent requirements of long-term high-load service under complex and demanding conditions, has become a key technical bottleneck that urgently needs to be overcome by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a high-abrasion-resistant HDPE monofilament, its preparation method, and its application.

[0006] Firstly, a high-abrasion-resistant HDPE monofilament is provided, employing the following technical solution: A high-wear-resistant HDPE monofilament, wherein the monofilament has a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 parts of silane-grafted HDPE masterbatch, 0.5 to 2.0 parts of composite catalyst, 0.2 to 0.6 parts of wear-resistant synergist, and 0.1 to 0.4 parts of antioxidant; the raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 parts of HDPE resin, 3 to 8 parts of modified silane monomer, 0.2 to 0.8 parts of composite initiator, 0.1 to 0.5 parts of anti-hydrolysis agent, and 0.3 to 0.9 parts of dispersant. The modified silane monomer is a compound of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 2:1 to 5:1; the composite initiator is a compound of dicumyl peroxide and benzoyl peroxide in a mass ratio of 3:1 to 6:1; the anti-hydrolysis agent is methyltriethoxysilane; the composite catalyst is a compound of dibutyltin dilaurate and stannous octoate in a mass ratio of 4:1 to 7:1; and the wear-resistant synergist is a compound of nano-silica with a particle size of 50 nm to 100 nm and polytetrafluoroethylene micro powder with a particle size of 1 μm to 5 μm in a mass ratio of 1:1 to 3:1.

[0007] Furthermore, the dispersant is a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 1:1 to 2:1; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 0.8:1 to 1.2:1.

[0008] Furthermore, the density of the HDPE resin is 0.940 g / cm³. 3 ~0.965 g / cm 3 The melt flow rate at 190℃ and 2.16 kg was 0.5 g / 10 min to 2.5 g / 10 min.

[0009] Secondly, a method for preparing high-abrasion-resistant HDPE monofilaments adopts the following technical solution: A method for preparing high abrasion-resistant HDPE monofilament includes the following steps: Step (1): HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent and dispersant are mixed and then melt-grafted in a twin-screw extruder. The mixture is then extruded, cooled, pelletized and dried to obtain silane-grafted HDPE masterbatch. Step (2): The silane-grafted HDPE masterbatch, composite catalyst, wear-resistant synergist and antioxidant obtained in step (1) are mixed and melt-spun in a single screw extrusion spinning machine. After the nascent monofilament is cooled and stretched, it is sent to the crosslinking box for hydrolysis and crosslinking reaction. Then it is dried with hot air, shaped and wound to obtain the HDPE high wear-resistant monofilament.

[0010] Further, in step (1), the mixing operation is carried out in a high-speed mixer, with a mixing temperature of 30 ℃~45 ℃, a mixing speed of 800 r / min~1200 r / min, and a mixing time of 5 min~10 min; The barrel temperature of the melt grafting reaction is set in the following sections: feeding section temperature is 120 ℃~140 ℃, compression section temperature is 150 ℃~170 ℃, reaction section temperature is 175 ℃~195 ℃, and die head section temperature is 180 ℃~200 ℃. The screw speed is 40 r / min~80 r / min, and the residence time of the material in the barrel is 3 min~8 min.

[0011] Further, in step (2), the mixing operation is carried out in a high-speed mixer, with a mixing temperature of 25 ℃~35 ℃, a mixing speed of 600 r / min~900 r / min, and a mixing time of 3 min~6 min; The temperature of the melt spinning barrel is set in the following sections: the temperature of the feeding section is 130 ℃~150 ℃, the temperature of the compression section is 160 ℃~180 ℃, the temperature of the metering section is 185 ℃~205 ℃, the temperature of the spinneret is 190 ℃~210 ℃, the screw speed is 20 r / min~50 r / min, and the spinneret orifice diameter is 0.2 mm~0.8 mm.

[0012] Further, in step (2), the cooling operation is: cooling to 25 ℃~40 ℃ via a cooling water tank; The stretching operation is carried out in a stretching machine at a temperature of 80 ℃ to 110 ℃ and a stretching ratio of 5 to 10 times.

[0013] Further, in step (2), the conditions for the hydrolysis crosslinking reaction are: reaction temperature of 60 ℃~85 ℃, relative humidity of 70 %~90%, and crosslinking time of 2 h~8 h; The hot air drying temperature is 50 ℃~70 ℃, and the drying time is 1 h~3 h; The temperature for the setting process is 100 ℃~120 ℃, and the setting time is 0.5 h~1.5 h.

[0014] Thirdly, an application of a high-abrasion-resistant HDPE monofilament employs the following technical solution: An application of HDPE high abrasion resistant monofilament as described above in the field of protective sleeves.

[0015] Furthermore, the protective sleeve includes a polyethylene braided mesh tube, heat-shrinkable fabric, heat-shrinkable tubing, and textile tubing, used for safety protection of the internal piping system of fuel vehicles and the wiring harness compartment of new energy vehicles.

[0016] The beneficial effects of this invention are: The HDPE high-wear-resistant monofilament provided by this invention achieves a comprehensive leap in material mechanical properties and wear resistance through the deep synergy of the compound system and cross-linking structure. In the silane grafting stage, the compound of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane, combined with the anti-hydrolysis agent methyltriethoxysilane, effectively inhibits the volatilization and early hydrolysis reaction of the monomer in the high-temperature molten state. Combined with a composite initiator composed of dicumyl peroxide and benzoyl peroxide, the reaction initiation temperature is significantly reduced, thereby achieving a stable grafting rate while avoiding excessive degradation of the high-density polyethylene main chain. In the cross-linking stage, the composite catalyst of dibutyltin dilaurate and stannous octoate promotes a more uniform and controllable hydrolysis-cross-linking reaction kinetics, thereby constructing a dense three-dimensional network of macromolecular cross-linked framework. Wear-resistant synergists composed of nano-silica of specific particle sizes and polytetrafluoroethylene micropowder are uniformly and firmly anchored within this three-dimensional cross-linked network. The rigid particles of nano-silica significantly enhance the surface hardness and deformation resistance of the monofilaments, while polytetrafluoroethylene (PTFE) micropowder imparts an extremely low surface friction coefficient to the material. Under the synergistic constraint of a dense cross-linked framework, both particles not only prevent agglomeration and stress-induced detachment but also form a dual-effect wear-resistant mechanism of enhanced hardness and low-friction slippage. This organic fusion, from microscopic chemical bonding to macroscopic physical blending, allows the monofilaments to significantly reduce surface wear while effectively avoiding embrittlement caused by excessive local cross-linking, maintaining excellent tensile strength and elongation at break. This breakthrough overcomes the performance limitations of traditional polymer material modification, which often struggles to balance high wear resistance and high toughness. Detailed Implementation

[0017] The following detailed description, in conjunction with embodiments, further illustrates the HDPE high-abrasion-resistant monofilament, its preparation method, and its application according to the present invention. For the sake of simplicity, this document cannot exhaustively list all alternative technical features and implementation schemes included in the present invention. Therefore, those skilled in the art should understand that any technical feature and implementation scheme within this embodiment does not limit the scope of protection of the present invention. The scope of protection includes all alternative technical features and implementation schemes adopted by those skilled in the art without creative effort. Specifically, any implementation scheme obtained by replacing any technical feature in the present invention or combining any two or more technical features provided by the present invention should be within the scope of protection of the present invention. Where specific techniques and conditions are not specified in the embodiments, they are performed according to the techniques and conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0018] Example Example 1 Example 1 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 1.2 g of composite catalyst, 0.4 g of wear-resistant synergist, and 0.25 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 5 g of modified silane monomer, 0.5 g of composite initiator, 0.3 g of anti-hydrolysis agent, and 0.6 g of dispersant.

[0019] The density of HDPE resin is 0.950 g / cm³. 3 The melt flow rate at 190 °C and 2.16 kg was 1.2 g / 10 min. The modified silane monomer was a mixture of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a 3:1 mass ratio. The composite initiator was a mixture of dicumyl peroxide and benzoyl peroxide in a 4:1 mass ratio. The hydrolysis inhibitor was methyltriethoxysilane. The dispersant was a mixture of zinc stearate and ethylene bis-stearamide in a 1.5:1 mass ratio. The composite catalyst was a mixture of dibutyltin dilaurate and stannous octoate in a 5:1 mass ratio. The wear-resistant synergist was a mixture of 80 nm nano-silica and 3 μm polytetrafluoroethylene micropowder in a 2:1 mass ratio. The antioxidant is a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:1.

[0020] This embodiment 1 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: Add the above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent, and dispersant to a high-speed mixer and mix for 8 minutes at a mixing temperature of 38 ℃ and a mixing speed of 1000 r / min to obtain a mixture.

[0021] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 130 ℃, compression section 160 ℃, reaction section 185 ℃, and die head section 190 ℃. The screw speed is set to 60 r / min, and the material residence time in the barrel is 5 min.

[0022] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 11.2%).

[0023] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 4.5 min at a mixing temperature of 30 ℃ and a mixing speed of 750 r / min to obtain the molding material.

[0024] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 140 ℃, compression section 170 ℃, metering section 195 ℃, and spinneret temperature 200 ℃. The screw speed is set to 35 r / min, and the spinneret orifice diameter is 0.5 mm.

[0025] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 32 ℃ in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 95 ℃ and the stretching ratio is 7.5 times.

[0026] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking chamber for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 75 ℃, relative humidity 80%, and crosslinking time 5 h.

[0027] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 60 ℃ for 2 hours; then they are set at a temperature of 110 ℃ for 1 hour; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilaments.

[0028] Example 2 This embodiment 2 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 0.5 g of composite catalyst, 0.2 g of wear-resistant synergist, and 0.1 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 3 g of modified silane monomer, 0.2 g of composite initiator, 0.1 g of anti-hydrolysis agent, and 0.3 g of dispersant.

[0029] The density of HDPE resin is 0.940 g / cm³. 3The melt flow rate at 190 °C and 2.16 kg was 0.5 g / 10 min. The modified silane monomer was a mixture of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a 2:1 mass ratio. The composite initiator was a mixture of dicumyl peroxide and benzoyl peroxide in a 3:1 mass ratio. The hydrolysis inhibitor was methyltriethoxysilane. The dispersant was a mixture of zinc stearate and ethylene bis-stearamide in a 1:1 mass ratio. The composite catalyst was a mixture of dibutyltin dilaurate and stannous octoate in a 4:1 mass ratio. The wear-resistant synergist was a mixture of 50 nm nano-silica and 1 μm polytetrafluoroethylene micropowder in a 1:1 mass ratio. The antioxidant is a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 0.8:1.

[0030] This embodiment 2 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: Add the above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent, and dispersant to a high-speed mixer and mix for 5 minutes at a mixing temperature of 30 ℃ and a mixing speed of 800 r / min to obtain a mixture.

[0031] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 120 ℃, compression section 150 ℃, reaction section 175 ℃, and die head section 180 ℃. The screw speed is set to 40 r / min, and the material residence time in the barrel is 3 min.

[0032] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 8.3%).

[0033] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 3 min at a mixing temperature of 25 ℃ and a mixing speed of 600 r / min to obtain the molding material.

[0034] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections: feeding section 130 ℃, compression section 160 ℃, metering section 185 ℃, and spinneret temperature 190 ℃. The screw speed is set to 20 r / min, and the spinneret orifice diameter is 0.2 mm.

[0035] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 25°C in a cooling water bath and then fed into a stretching machine for stretching. The stretching temperature is controlled at 80°C and the stretching ratio is 5 times.

[0036] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking chamber for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 60 ℃, relative humidity 70%, and crosslinking time 8 h.

[0037] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 50 ℃ for 1 h; then they are set at a temperature of 100 ℃ for 0.5 h; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilament.

[0038] Example 3 This embodiment 3 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 2.0 g of composite catalyst, 0.6 g of wear-resistant synergist, and 0.4 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 8 g of modified silane monomer, 0.8 g of composite initiator, 0.5 g of anti-hydrolysis agent, and 0.9 g of dispersant.

[0039] The density of HDPE resin is 0.965 g / cm³. 3The melt flow rate at 190 °C and 2.16 kg was 2.5 g / 10 min. The modified silane monomer was a mixture of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 5:1. The composite initiator was a mixture of dicumyl peroxide and benzoyl peroxide in a mass ratio of 6:1. The anti-hydrolysis agent was methyltriethoxysilane. The dispersant was a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 2:1. The composite catalyst was a mixture of dibutyltin dilaurate and stannous octoate in a mass ratio of 7:1. The wear-resistant synergist was a mixture of 100 nm nano-silica and 5 μm polytetrafluoroethylene micropowder in a mass ratio of 3:1. The antioxidant is a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1.2:1.

[0040] This embodiment 3 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: Add the above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent, and dispersant to a high-speed mixer and mix for 10 min at a mixing temperature of 45 ℃ and a mixing speed of 1200 r / min to obtain a mixture.

[0041] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 140 ℃, compression section 170 ℃, reaction section 195 ℃, and die head section 200 ℃. The screw speed is set to 80 r / min, and the material residence time in the barrel is 8 min.

[0042] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 14.7%).

[0043] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 6 min at a mixing temperature of 35 ℃ and a mixing speed of 900 r / min to obtain the molding material.

[0044] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 150 ℃, compression section 180 ℃, metering section 205 ℃, and spinneret temperature 210 ℃. The screw speed is set to 50 r / min, and the spinneret orifice diameter is 0.8 mm.

[0045] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 40°C in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 110°C and the stretching ratio is 10 times.

[0046] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking box for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 85 ℃, relative humidity 90%, and crosslinking time 2 h.

[0047] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 70 ℃ for 3 hours; then they are set at a temperature of 120 ℃ for 1.5 hours; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilaments.

[0048] Example 4 Example 4 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 0.8 g of composite catalyst, 0.3 g of wear-resistant synergist, and 0.2 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 4 g of modified silane monomer, 0.3 g of composite initiator, 0.2 g of anti-hydrolysis agent, and 0.4 g of dispersant.

[0049] The density of HDPE resin is 0.945 g / cm³. 3 The melt flow rate at 190 °C and 2.16 kg was 0.8 g / 10 min. The modified silane monomer was a compound of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 2.5:1. The composite initiator was a compound of dicumyl peroxide and benzoyl peroxide in a mass ratio of 3.5:1. The anti-hydrolysis agent was methyltriethoxysilane. The dispersant was a compound of zinc stearate and ethylene bis-stearamide in a mass ratio of 1.2:1. The composite catalyst was a compound of dibutyltin dilaurate and stannous octoate in a mass ratio of 4.5:1. The wear-resistant synergist was a compound of 60 nm nano-silica and 2 μm polytetrafluoroethylene micropowder in a mass ratio of 1.5:1. The antioxidant was a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0050] This embodiment 4 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: The above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent and dispersant are added to a high-speed mixer and mixed for 6 min at a mixing temperature of 32 ℃ and a mixing speed of 900 r / min to obtain a mixture.

[0051] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 125 ℃, compression section 155 ℃, reaction section 180 ℃, and die head section 185 ℃. The screw speed is set to 50 r / min, and the material residence time in the barrel is 4 min.

[0052] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 11.0%).

[0053] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 4 min at a mixing temperature of 28 ℃ and a mixing speed of 700 r / min to obtain the molding material.

[0054] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 135 ℃, compression section 165 ℃, metering section 190 ℃, and spinneret temperature 195 ℃. The screw speed is set to 30 r / min, and the spinneret orifice diameter is 0.4 mm.

[0055] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 28 ℃ in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 90 ℃ and the stretching ratio is 6 times.

[0056] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking chamber for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 65 ℃, relative humidity 75%, and crosslinking time 6 h.

[0057] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 55 ℃ for 1.5 h; then they are set at a temperature of 105 ℃ for 0.8 h; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilaments.

[0058] Example 5 This embodiment 5 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 1.5 g of composite catalyst, 0.5 g of wear-resistant synergist, and 0.3 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 6 g of modified silane monomer, 0.6 g of composite initiator, 0.4 g of anti-hydrolysis agent, and 0.8 g of dispersant.

[0059] The density of HDPE resin is 0.955 g / cm³. 3 The melt flow rate at 190 °C and 2.16 kg was 1.8 g / 10 min. The modified silane monomer was a mixture of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 4:1. The composite initiator was a mixture of dicumyl peroxide and benzoyl peroxide in a mass ratio of 5:1. The anti-hydrolysis agent was methyltriethoxysilane. The dispersant was a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 1.8:1. The composite catalyst was a mixture of dibutyltin dilaurate and stannous octoate in a mass ratio of 6:1. The wear-resistant synergist was a mixture of 90 nm nano-silica and 4 μm polytetrafluoroethylene micropowder in a mass ratio of 2.5:1. The antioxidant was a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0060] This embodiment 5 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: The above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent and dispersant are added to a high-speed mixer and mixed for 9 min at a mixing temperature of 42 ℃ and a mixing speed of 1100 r / min to obtain a mixture.

[0061] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 135 ℃, compression section 165 ℃, reaction section 190 ℃, and die head section 195 ℃. The screw speed is set to 70 r / min, and the material residence time in the barrel is 6 min.

[0062] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 11.3%).

[0063] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 5 min at a mixing temperature of 32 ℃ and a mixing speed of 850 r / min to obtain the molding material.

[0064] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 145 ℃, compression section 175 ℃, metering section 200 ℃, and spinneret temperature 205 ℃. The screw speed is set to 45 r / min, and the spinneret orifice diameter is 0.6 mm.

[0065] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 35°C in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 100°C and the stretching ratio is 8 times.

[0066] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking box for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 80 ℃, relative humidity 85%, and crosslinking time 4 h.

[0067] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 65 ℃ for 2.5 h; then they are set at a temperature of 115 ℃ for 1.2 h; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilaments.

[0068] Example 6 Example 6 provides a high-wear-resistant HDPE monofilament with a three-dimensional network structure formed by silane hydrolysis and crosslinking. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 1.0 g of composite catalyst, 0.35 g of wear-resistant synergist, and 0.35 g of antioxidant. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 7 g of modified silane monomer, 0.4 g of composite initiator, 0.35 g of anti-hydrolysis agent, and 0.5 g of dispersant.

[0069] The density of HDPE resin is 0.960 g / cm³. 3The melt flow rate at 190 °C and 2.16 kg was 2.0 g / 10 min. The modified silane monomer was a compound of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 3.5:1. The composite initiator was a compound of dicumyl peroxide and benzoyl peroxide in a mass ratio of 4.5:1. The anti-hydrolysis agent was methyltriethoxysilane. The dispersant was a compound of zinc stearate and ethylene bis-stearamide in a mass ratio of 1.6:1. The composite catalyst was a compound of dibutyltin dilaurate and stannous octoate in a mass ratio of 5.5:1. The wear-resistant synergist was a compound of 70 nm nano-silica and 2.5 μm polytetrafluoroethylene micropowder in a mass ratio of 2.2:1. The antioxidant was a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0070] This embodiment 6 provides a method for preparing HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing: Add the above-mentioned weights of HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent, and dispersant to a high-speed mixer and mix for 7 minutes at a mixing temperature of 40 ℃ and a mixing speed of 1050 r / min to obtain a mixture.

[0071] Melt grafting: The above mixture is fed into a twin-screw extruder for melt grafting reaction. The barrel temperature is set in sections: feeding section 128 ℃, compression section 158 ℃, reaction section 182 ℃, and die head section 188 ℃. The screw speed is set to 65 r / min, and the material residence time in the barrel is 7 min.

[0072] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch (the grafting rate of the masterbatch was measured to be 11.1%).

[0073] Step (2), prepare HDPE high abrasion resistant monofilament: Mixing: 100 g of silane-grafted HDPE masterbatch obtained in step (1) is added to a high-speed mixer in proportion to the composite catalyst, wear-resistant synergist and antioxidant. The mixture is mixed for 5.5 min at a mixing temperature of 33 ℃ and a mixing speed of 850 r / min to obtain the molding material.

[0074] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 142 ℃, compression section 172 ℃, metering section 198 ℃, and spinneret temperature 202 ℃. The screw speed is set to 40 r / min, and the spinneret orifice diameter is 0.7 mm.

[0075] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 38 ℃ in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 105 ℃ and the stretching ratio is 9 times.

[0076] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking chamber for hydrolysis and crosslinking reaction. The reaction conditions are strictly controlled as follows: reaction temperature 70 ℃, relative humidity 78%, and crosslinking time 7 h.

[0077] Post-processing and winding: The cross-linked monofilaments are dried by hot air at a temperature of 58 ℃ for 2.8 h; then they are set at a temperature of 108 ℃ for 0.8 h; finally, they are wound up by a winding machine to obtain the HDPE high abrasion resistant monofilaments.

[0078] Comparative Example Comparative Example 1 Comparative Example 1 provides a common HDPE monofilament, the raw materials for preparing the monofilament comprising, by weight only: 100 g HDPE resin and 0.25 g antioxidant.

[0079] The density of HDPE resin is 0.950 g / cm³. 3 The melt flow rate at 190 °C and 2.16 kg was 1.2 g / 10 min. The antioxidant was a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:1.

[0080] Comparative Example 1 provides a method for preparing ordinary HDPE monofilaments, specifically including the following steps: Mixing: Add the above-mentioned weight of HDPE resin and antioxidant to a high-speed mixer and mix for 4.5 min at a mixing temperature of 30 ℃ and a mixing speed of 750 r / min to obtain the molding material.

[0081] Melt spinning: The shaped material is fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections as follows: feeding section 140 ℃, compression section 170 ℃, metering section 195 ℃, and spinneret temperature 200 ℃. The screw speed is set to 35 r / min, and the spinneret orifice diameter is 0.5 mm.

[0082] Cooling and stretching: The nascent monofilaments extruded from the spinning process are cooled to 32 ℃ in a cooling water bath and then sent to a stretching machine for stretching. The stretching temperature is controlled at 95 ℃ and the stretching ratio is 7.5 times.

[0083] Post-processing and winding: Without cross-linking reaction, the stretched monofilaments are directly subjected to setting treatment at a temperature of 110 ℃ for 1 h; finally, they are wound up by a winding machine to obtain ordinary HDPE monofilaments.

[0084] Comparative Example 2 Comparative Example 2 provides an HDPE monofilament having a cross-linked network. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 1.2 g of a single catalyst, and 0.25 g of antioxidant. No wear-resistant synergist is used. The raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 g of HDPE resin, 5 g of a single silane monomer, 0.5 g of a single initiator, 0.3 g of anti-hydrolysis agent, and 0.6 g of dispersant.

[0085] The single silane monomer is vinyltrimethoxysilane. The single initiator is dicumyl peroxide. The single catalyst is dibutyltin dilaurate. The composition and parameters of all other raw materials are the same as in Example 1.

[0086] Comparative Example 2 provides a method for preparing HDPE monofilaments, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: Mixing and melt grafting: The above-mentioned weights of HDPE resin, single silane monomer, single initiator, anti-hydrolysis agent, and dispersant were added to a high-speed mixer and mixed for 8 minutes to obtain a mixture, which was then fed into a twin-screw extruder for melt grafting reaction. The barrel temperature was set in the following sections: feeding section 130 ℃, compression section 160 ℃, reaction section 185 ℃, and die head section 190 ℃; the screw speed was 60 r / min, and the residence time was 5 minutes.

[0087] Granulation: After extrusion, the material is water-cooled, granulated, and dried to obtain silane-grafted HDPE masterbatch.

[0088] Step (2), preparing HDPE monofilaments: Mixing and spinning: 100 g of the masterbatch obtained in step (1) was mixed with a single catalyst and antioxidant in a high-speed mixer for 4.5 min, and then fed into a single-screw extrusion spinning machine for melt spinning. The process parameters were the same as in Example 1.

[0089] Cooling and stretching: After the nascent monofilament is cooled to 32 ℃, it is stretched 7.5 times at 95 ℃.

[0090] Hydrolysis crosslinking and winding: The stretched monofilaments are crosslinked at 75 ℃ and 80% relative humidity for 5 h, and then wound up after hot air drying and setting at 110 ℃ for 1 h to obtain the HDPE monofilament.

[0091] Comparative Example 3 Comparative Example 3 provides a high-abrasion-resistant HDPE monofilament, whose raw material ratio is exactly the same as that in Example 1, but it is prepared by a one-step method.

[0092] Comparative Example 3 provides a method for preparing high abrasion-resistant HDPE monofilament, specifically including the following steps: Mixing: 100 g HDPE resin, 5 g modified silane monomer, 0.5 g composite initiator, 0.3 g anti-hydrolysis agent, 0.6 g dispersant, 1.2 g composite catalyst, 0.4 g wear-resistant synergist, and 0.25 g antioxidant were added to a high-speed mixer at one time and mixed for 8 min at a mixing temperature of 38 ℃ and a mixing speed of 1000 r / min to obtain a mixture.

[0093] Melt spinning: The mixture is directly fed into a single-screw extrusion spinning mill for melt spinning. The barrel temperature is set in sections: feeding section 140 ℃, compression section 170 ℃, metering section 195 ℃, and spinneret temperature 200 ℃. The screw speed is set to 35 r / min, and the spinneret orifice diameter is 0.5 mm.

[0094] Cooling and stretching: After the nascent monofilament is cooled to 32 ℃ in a cooling water tank, it is sent to a stretching machine for stretching operation. The stretching temperature is controlled at 95 ℃ and the stretching ratio is 7.5 times.

[0095] Hydrolysis and crosslinking: The stretched monofilaments are sent into a crosslinking chamber for hydrolysis and crosslinking reaction at a temperature of 75 ℃ and a relative humidity of 80% for 5 h.

[0096] Post-processing and winding: After drying with hot air at 60 ℃ for 2 h and setting at 110 ℃ for 1 h, HDPE monofilaments are obtained by winding.

[0097] Comparative Example 4 Comparative Example 4 provides an HDPE monofilament, the proportions of which are exactly the same as those in Example 1.

[0098] Comparative Example 4 provides a method for preparing HDPE monofilaments, which is completely consistent with Example 1 except that the hydrolysis crosslinking step is omitted. Specifically, it includes the following steps: Step (1), Preparation of silane-grafted HDPE masterbatch: The process parameters of Example 1 are used for mixing, melt grafting (twin-screw extrusion) and granulation to obtain silane-grafted HDPE masterbatch.

[0099] Step (2), preparing HDPE monofilaments: Mixing and spinning: 100 g of masterbatch obtained in step (1) was mixed with 1.2 g of composite catalyst, 0.4 g of wear-resistant synergist and 0.25 g of antioxidant, and then fed into a single screw extrusion spinning machine for melt spinning, with the same parameters as in Example 1.

[0100] Cooling and stretching: After the monofilament is cooled to 32 ℃, it is stretched 7.5 times at 95 ℃.

[0101] Post-processing and winding: The stretched monofilaments are not sent to the cross-linking box for cross-linking. They are directly set at 110 ℃ for 1 h and finally wound up by a winding machine to obtain HDPE monofilaments.

[0102] Comparative Example 5 Comparative Example 5 provides an HDPE monofilament with a cross-linked network. The raw materials for preparing the monofilament, by weight, include: 100 g of silane-grafted HDPE masterbatch, 1.2 g of composite catalyst, and 0.25 g of antioxidant. The difference from Example 1 is that no wear-resistant synergist is added. The raw materials for preparing the silane-grafted HDPE masterbatch are the same as in Example 1.

[0103] Comparative Example 5 provides a method for preparing HDPE monofilaments, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: process is the same as in Example 1.

[0104] Step (2), preparing HDPE monofilaments: Mixing: Add 100 g of silane-grafted HDPE masterbatch obtained in step (1) to 1.2 g of composite catalyst and 0.25 g of antioxidant (without wear-resistant synergist) in a high-speed mixer and mix for 4.5 min to obtain the molding material.

[0105] All parameters and operating steps for melt spinning, cooling and stretching, hydrolysis crosslinking and post-treatment winding were completely consistent with those in Example 1, resulting in HDPE monofilaments.

[0106] Comparative Example 6 Comparative Example 6 provides a high-abrasion-resistant HDPE monofilament, differing from Example 1 only in that: when preparing the silane-grafted HDPE masterbatch, all 5 g of modified silane monomer used were vinyltrimethoxysilane, i.e., not compounded with KH-570. All other components and proportions are completely identical to those in Example 1.

[0107] Comparative Example 6 provides a method for preparing this high abrasion-resistant HDPE monofilament, specifically including the following steps: Step (1), Preparation of silane-grafted HDPE masterbatch: Mix 100 g HDPE resin, 5 g VTMS monomer, 0.5 g composite initiator, 0.3 g anti-hydrolysis agent and 0.6 g dispersant, and perform melt grafting and granulation according to the extrusion parameters of Example 1.

[0108] Step (2), preparing HDPE high wear-resistant monofilament: using the above masterbatch combined with composite catalyst, wear-resistant enhancer and antioxidant, the same mixing, spinning, stretching, crosslinking and post-treatment process as in Example 1 is followed, and finally the monofilament is wound up.

[0109] Comparative Example 7 Comparative Example 7 provides a high-abrasion-resistant HDPE monofilament, differing from Example 1 only in that: when preparing the silane-grafted HDPE masterbatch, the 0.5 g composite initiator used was completely replaced with an equal weight (0.5 g) of dicumyl peroxide (DCP), i.e., BPO was not used for compounding. All other components and proportions are completely consistent with Example 1.

[0110] Comparative Example 7 provides a method for preparing this high abrasion-resistant HDPE monofilament, specifically including the following steps: Step (1), Preparation of silane-grafted HDPE masterbatch: Mix 100 g HDPE resin, 5 g modified silane monomer, 0.5 g single initiator (DCP), 0.3 g anti-hydrolysis agent and 0.6 g dispersant, and perform melt grafting and granulation according to the extrusion parameters of Example 1.

[0111] Step (2), preparing HDPE high abrasion resistant monofilament: using the above masterbatch, combined with composite catalyst, abrasion synergist and antioxidant, the spinning, stretching, crosslinking and setting process is carried out and wound up in the same manner as in Example 1.

[0112] Comparative Example 8 Comparative Example 8 provides a high-abrasion-resistant HDPE monofilament, which differs from Example 1 only in that: when preparing the monofilament, the 1.2 g composite catalyst added in step (2) is completely replaced with an equal weight (1.2 g) of dibutyltin dilaurate (DBTDL), that is, it is not compounded with stannous octoate. The remaining components and proportions are completely consistent with those of Example 1.

[0113] Comparative Example 8 provides a method for preparing this high abrasion-resistant HDPE monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: raw materials and process parameters are the same as in Example 1.

[0114] Step (2), preparing HDPE high wear-resistant monofilament: 100 g of silane-grafted HDPE masterbatch obtained in step (1), 1.2 g of single catalyst (DBTDL), 0.4 g of wear-resistant synergist and 0.25 g of antioxidant are mixed, and then the same extrusion spinning, stretching, crosslinking reaction and post-treatment process as in Example 1 is followed, and finally the monofilament is wound up.

[0115] Comparative Example 9 Comparative Example 9 provides a high-abrasion-resistant HDPE monofilament, which differs from Example 1 only in that: when preparing the monofilament, the 0.4 g abrasion-resistant synergist added in step (2) is completely replaced with an equal weight (0.4 g) of nano-silica with a particle size of 80 nm, that is, it is not compounded with polytetrafluoroethylene micro powder. The remaining components and proportions are completely consistent with those of Example 1.

[0116] Comparative Example 9 provides a method for preparing the HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: raw materials and process parameters are the same as in Example 1.

[0117] Step (2), preparing HDPE high abrasion resistant monofilament: 100 g of silane-grafted HDPE masterbatch, 1.2 g of composite catalyst, 0.4 g of nano silica and 0.25 g of antioxidant obtained in step (1) are mixed, and then the same single screw spinning, cooling stretching, crosslinking and shaping process as in Example 1 is performed and wound up.

[0118] Comparative Example 10 Comparative Example 10 provides a high-abrasion-resistant HDPE monofilament, differing from Example 1 only in that the anti-hydrolysis agent (methyltriethoxysilane) is not added during the preparation of the silane-grafted HDPE masterbatch, i.e., this 0.3 g component is omitted. All other components and their weight ratios remain consistent with Example 1.

[0119] Comparative Example 10 provides a method for preparing the HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), Preparation of silane-grafted HDPE masterbatch: 100 g HDPE resin, 5 g modified silane monomer, 0.5 g composite initiator and 0.6 g dispersant were added to a high-speed mixer and mixed for 8 min. Then, the melt grafting reaction and granulation were carried out according to the twin-screw temperature and speed parameters of Example 1.

[0120] Step (2), preparing HDPE high abrasion resistant monofilament: using the masterbatch obtained by the above-mentioned missing anti-hydrolysis agent system, combined with composite catalyst, abrasion synergist and antioxidant, the spinning, cooling, stretching, hydrolysis crosslinking and winding processes are completed in full according to the parameters corresponding to Example 1.

[0121] Comparative Example 11 Comparative Example 11 provides a high-abrasion-resistant HDPE monofilament, differing from Example 1 only in that: in preparing the silane-grafted HDPE masterbatch, 5g of modified silane monomer is prepared by compounding vinyltrimethoxysilane (VTMS) and γ-methacryloyloxypropyltrimethoxysilane (KH-570) in a 1:1 mass ratio. All other raw material components, proportions, and process parameters are completely consistent with Example 1.

[0122] Comparative Example 11 provides a method for preparing the HDPE high abrasion-resistant monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: 100 g HDPE resin, 5 g modified silane monomer (VTMS and KH-570 mass ratio 1:1), 0.5 g composite initiator, 0.3 g anti-hydrolysis agent and 0.6 g dispersant are mixed and melt-grafted and granulated according to the extrusion parameters of Example 1.

[0123] Step (2), preparing HDPE high abrasion resistant monofilament: using the above masterbatch combined with composite catalyst, abrasion synergist and antioxidant, the same mixing, spinning, stretching, crosslinking and post-treatment process as in Example 1 is followed, and finally the monofilament is wound up.

[0124] Comparative Example 12 Comparative Example 12 provides a high-abrasion-resistant HDPE monofilament, differing from Example 1 only in that: in preparing the silane-grafted HDPE masterbatch, 5g of modified silane monomer is prepared by compounding vinyltrimethoxysilane (VTMS) and γ-methacryloyloxypropyltrimethoxysilane (KH-570) at a mass ratio of 6:1. All other raw material components, proportions, and process parameters are completely consistent with Example 1.

[0125] Comparative Example 12 provides a method for preparing the high abrasion-resistant HDPE monofilament, specifically including the following steps: Step (1), preparation of silane-grafted HDPE masterbatch: 100 g HDPE resin, 5 g modified silane monomer (VTMS and KH-570 mass ratio 6:1), 0.5 g composite initiator, 0.3 g anti-hydrolysis agent and 0.6 g dispersant are mixed and melt-grafted and granulated according to the extrusion parameters of Example 1.

[0126] Step (2), preparing HDPE high abrasion resistant monofilament: using the above masterbatch combined with composite catalyst, abrasion synergist and antioxidant, the same mixing, spinning, stretching, crosslinking and post-treatment process as in Example 1 is followed, and finally the monofilament is wound up.

[0127] Application Examples Application Example 1: Heat Shrink Tubing for Wiring Harness Compartment in New Energy Vehicles This application example 1 provides a heat shrink tubing prepared based on the HDPE high abrasion resistant monofilament obtained in example 1 and its application in the safety protection of the wiring harness compartment of new energy vehicles.

[0128] 1. Preparation process of protective sleeve: Warping and weaving: The HDPE high abrasion resistant monofilaments prepared in Example 1 are used as warp and weft yarns and are circularly woven by a high-speed weaving machine. The weaving angle is controlled between 45° and 60° to prepare a polyethylene braided mesh tube substrate with a specific pipe diameter.

[0129] Composite and expansion: The above-mentioned braided mesh substrate is co-extruded with the hot melt adhesive layer (or the inner wall is coated with hot melt adhesive), and then fed into an expansion machine. Mechanical radial expansion is performed at a temperature above the resin softening point. After expansion, it is rapidly cooled and shaped to give it a heat shrinkage memory effect, thus producing a braided heat shrink tubing.

[0130] Cutting and winding: According to the specifications of new energy vehicle wiring harnesses, heat shrink tubing is cut to the specified length or packaged in rolls.

[0131] 2. Application and measured performance: The heat shrink tubing was fitted onto the outside of the high-voltage wiring harness inside the engine compartment of a new energy vehicle, and heated with a heat gun to shrink it tightly against the surface of the wiring harness. Real vehicle and laboratory simulation tests were conducted. Under wide temperature range cycling conditions from -40℃ to 150℃, the sheath shrinkage rate remains stable at over 98%, with no cracking, deformation, or performance degradation.

[0132] In the ISO6722 / TL5266 standard abrasion resistance test, using commercially available ordinary irradiated cross-linked PE heat shrink tubing of the same specifications as a control group, the abrasion resistance life of the sheath prepared in this application example was improved by 30% and passed SGS certification, fully complying with RoHS and REACH environmental directives.

[0133] Application Example 2: Braided mesh tubing for internal piping systems in fuel-powered vehicles This application example 2 provides a braided mesh tube prepared based on the HDPE high abrasion resistant monofilament obtained in example 1 and its application in anti-friction protection of the internal piping system of fuel vehicles.

[0134] 1. Preparation process of protective sleeve: Doubling and winding: The monofilaments prepared in Example 1 are doubled and wound onto a spindle for a braiding machine to ensure uniform tension of the monofilaments.

[0135] Multi-axis braiding: Using a 24-spindle or 36-spindle cross-braiding machine, monofilaments are interwoven and braided into a tubular braided mesh with a high expansion rate in a three-filament-per-spindle or multi-filament-per-spindle pattern. During the weaving process, the coverage rate of the mesh is controlled to reach over 85%.

[0136] Heat setting treatment: The formed braided mesh tube is briefly heat-set in a heat setting oven at 110℃~120℃ to eliminate internal stress in the braid, prevent monofilaments from unraveling, and maintain the flexibility and elasticity of the mesh tube.

[0137] 2. Application and measured performance: The braided mesh tube can be directly fitted onto the outside of fuel delivery lines and coolant lines in the chassis and engine compartment of a gasoline-powered vehicle. Its expandability due to its mesh structure allows for quick installation, and both ends are secured with cable ties or clamps.

[0138] In the third-party accelerated aging test, after 1000 hours of double 85 composite testing (85℃, 85% humidity), the sheath surface showed no powdering or cracking, and the wear resistance performance retention rate was ≥95%.

[0139] It effectively resists mechanical friction between the pipeline and the frame, and between pipelines themselves, during vehicle operation, significantly extending the safe service life of the fuel pipeline.

[0140] Performance Testing and Result Analysis I. Performance Testing Indicators and Methods To comprehensively evaluate the physical and mechanical properties, microstructure, and appearance quality of the HDPE monofilaments prepared in the embodiments and comparative examples of the present invention, the following indicators and test methods were adopted.

[0141] 1. Grafting Rate Test: The grafting rate was determined using the Soxhlet extraction method. The prepared silane-grafted HDPE masterbatch was sliced ​​and accurately weighed, then placed in a Soxhlet extractor. Using xylene as the solvent, extraction was performed continuously for 48 hours under reflux to completely dissolve and remove unreacted free silane monomers and self-polymers. After extraction, the remaining insoluble material was placed in a vacuum drying oven and dried at 80°C to constant weight. The grafting rate was calculated based on the mass difference of the sample before and after extraction. The average value of three parallel tests was taken for each group.

[0142] 2. Wear Test: Plastic sliding friction and wear tests were conducted according to GB / T 3960 standard. A fixed-length monofilament sample was tightly wound and fixed onto the test wheel of the wear testing machine. A standard friction wheel was used to apply a constant contact load of 10 N, and continuous friction testing was performed at a rotation speed of 1000 r / min. The mass change of the sample before and after the test was accurately measured, and the wear amount (unit: mg / 1000 r) was calculated. The smaller this value, the better the wear resistance of the monofilament.

[0143] 3. Tensile Strength and Elongation at Break Test: The tensile properties of monofilaments were determined according to GB / T 1040.2 standard. Monofilament specimens approximately 200 mm in length were cut and conditioned for 24 hours under standard constant temperature and humidity conditions (temperature 23±2℃, relative humidity 50±5%). A universal testing machine was used, with the initial distance between the upper and lower clamps set to 100 mm and a constant tensile rate of 50 mm / min for room temperature tensile testing. The maximum stress and gauge length elongation at break were automatically recorded, and the tensile strength (MPa) and elongation at break (%) were calculated. Five samples were tested in each group, and their arithmetic mean was taken.

[0144] 4. Surface Smoothness Assessment: Under sufficient natural light or standard light source illumination, professional inspectors will conduct a macroscopic visual assessment and tactile inspection of the surface of the heat-set and wound HDPE monofilaments. If the monofilament surface is continuous and uniform, without exudates, scratches, burrs, or obvious unevenness, the surface smoothness is judged as "qualified"; if there is local roughness or granulation, it is recorded as "slight burrs" or "obvious burrs".

[0145] 5. Diameter Deviation Test: Using a digital vernier caliper or online laser diameter gauge with an accuracy of 0.001 mm, randomly select a 10-meter sample section along the length of the finished monofilament after winding, and measure the outer diameter at 10 different locations at equal intervals. Record the readings at each measuring point, calculate the difference between the reading and the set standard wire diameter, and take the maximum absolute deviation value as the diameter deviation (±mm) of the batch of monofilaments.

[0146] II. Performance Test Results The samples prepared in Examples 1-6 and Comparative Examples 1-10 were subjected to the above tests, and the performance test results are shown in Table 1 below.

[0147] Table 1 Performance test results of HDPE monofilaments provided in Examples 1-6 and Comparative Examples 1-10

[0148] Based on the test data from Examples 1-6, all embodiments provided by this invention achieved a stable and controllable grafting rate between 8.3% and 14.7%, with abrasion loss effectively suppressed below 28.7 mg / 1000 r, and tensile strength exceeding a high level of 35 MPa, while maintaining excellent surface quality and diameter tolerance. Even under the relatively low raw material and process parameter conditions of Example 2, good overall performance was still achieved; while under the parameter conditions of Example 3, although the elongation at break decreased slightly due to the increased crosslinking density, its abrasion loss reached an excellent level of 20.1 mg / 1000 r, and the tensile strength even climbed to 40.3 MPa.

[0149] In the verification of comparative examples and Example 1, the wear rates of Comparative Examples 1 and 4, which did not introduce modified and cross-linked structures, were as high as 38.5 mg / 1000r and 35.2 mg / 1000r, respectively. The wear rate of Comparative Example 5, which lacked the wear-resistant synergist, also rebounded to 31.6 mg / 1000r, far inferior to the 22.3 mg / 1000r of Example 1. This proves that neither simple physical blending nor pure chemical cross-linking can achieve ultimate wear resistance. Only when the nanofiller is firmly anchored in the three-dimensional network framework formed by hydrolysis and cross-linking can a synergistic qualitative change in hardness and low-friction slip be triggered. Regarding the core compounding characteristics of this invention, Comparative Examples 2 and 3, which used a single system and a one-step cross-linking method, not only had grafting rates reduced to 6.8% and 5.3%, but also suffered from severe burrs and dimensional instability on the monofilament surface due to the intense cross-linking reaction. In particular, the verification of the silane compound boundary in Comparative Examples 11 and 12 showed that when the ratio of VTMS to KH-570 decreased to 1:1 (Comparative Example 11), the lack of dominant crosslinking activity in VTMS led to a grafting rate of 7.8%, resulting in a significant decrease in wear resistance. When this ratio increased to 6:1 (Comparative Example 12), excessive local crosslinking caused severe locking of polymer chain segments, resulting in a drop in elongation at break to 370% and the appearance of slight burrs on the surface. Comparative Example 10, lacking an anti-hydrolysis agent, directly suffered from early hydrolysis, causing the grafting rate to drop to 6.5%, thus compromising mechanical properties.

[0150] In summary, this invention successfully constructed a three-dimensional cross-linked network of siloxanes at the molecular chain level through component compounding and physical-mechanical processing steps, encapsulating dual-effect wear-resistant nanoparticles. Test data shows that this microstructure reshaping fundamentally overcomes problems such as monomer volatilization, localized excessive cross-linking, and filler agglomeration and peeling. While significantly reducing the frictional wear of single filaments, it achieves a leap in tensile strength and precise control of surface dimensions, successfully realizing the performance that is difficult to achieve simultaneously in existing technologies, namely high wear resistance and high toughness.

[0151] For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, but obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this invention.

Claims

1. A high-abrasion-resistant HDPE monofilament, characterized in that, The monofilament has a three-dimensional network structure formed by silane hydrolysis and cross-linking. The raw materials for preparing the monofilament, by weight, include: 100 parts of silane-grafted HDPE masterbatch, 0.5 to 2.0 parts of composite catalyst, 0.2 to 0.6 parts of wear-resistant synergist, and 0.1 to 0.4 parts of antioxidant; the raw materials for preparing the silane-grafted HDPE masterbatch, by weight, include: 100 parts of HDPE resin, 3 to 8 parts of modified silane monomer, 0.2 to 0.8 parts of composite initiator, 0.1 to 0.5 parts of anti-hydrolysis agent, and 0.3 to 0.9 parts of dispersant. The modified silane monomer is a compound of vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane in a mass ratio of 2:1 to 5:1; the composite initiator is a compound of dicumyl peroxide and benzoyl peroxide in a mass ratio of 3:1 to 6:1; the anti-hydrolysis agent is methyltriethoxysilane; the composite catalyst is a compound of dibutyltin dilaurate and stannous octoate in a mass ratio of 4:1 to 7:1; and the wear-resistant synergist is a compound of nano-silica with a particle size of 50 nm to 100 nm and polytetrafluoroethylene micro powder with a particle size of 1 μm to 5 μm in a mass ratio of 1:1 to 3:

1.

2. The HDPE high abrasion-resistant monofilament according to claim 1, characterized in that, The dispersant is a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 1:1 to 2:1; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 0.8:1 to 1.2:

1.

3. The HDPE high abrasion-resistant monofilament according to claim 1, characterized in that, The density of the HDPE resin is 0.940 g / cm³. 3 ~0.965 g / cm 3 The melt flow rate was 0.5 g / 10 min to 2.5 g / 10 min at 190 °C and 2.16 kg.

4. A method for preparing HDPE high abrasion-resistant monofilament as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step (1): HDPE resin, modified silane monomer, composite initiator, anti-hydrolysis agent and dispersant are mixed and then melt-grafted in a twin-screw extruder. The mixture is then extruded, cooled, pelletized and dried to obtain silane-grafted HDPE masterbatch. Step (2): The silane-grafted HDPE masterbatch, composite catalyst, wear-resistant synergist and antioxidant obtained in step (1) are mixed and melt-spun in a single screw extrusion spinning machine. After the nascent monofilament is cooled and stretched, it is sent to the crosslinking box for hydrolysis and crosslinking reaction. Then it is dried with hot air, shaped and wound to obtain the HDPE high wear-resistant monofilament.

5. The preparation method according to claim 4, characterized in that, In step (1), the mixing operation is carried out in a high-speed mixer, with a mixing temperature of 30 ℃~45 ℃, a mixing speed of 800 r / min~1200 r / min, and a mixing time of 5 min~10 min; The barrel temperature of the melt grafting reaction is set in the following sections: feeding section temperature is 120 ℃~140 ℃, compression section temperature is 150 ℃~170 ℃, reaction section temperature is 175 ℃~195 ℃, and die head section temperature is 180 ℃~200 ℃. The screw speed is 40 r / min~80 r / min, and the residence time of the material in the barrel is 3 min~8 min.

6. The preparation method according to claim 4, characterized in that, In step (2), the mixing operation is carried out in a high-speed mixer, with a mixing temperature of 25 ℃~35 ℃, a mixing speed of 600 r / min~900 r / min, and a mixing time of 3 min~6 min; The temperature of the melt spinning barrel is set in the following sections: the temperature of the feeding section is 130 ℃~150 ℃, the temperature of the compression section is 160 ℃~180 ℃, the temperature of the metering section is 185 ℃~205 ℃, the temperature of the spinneret is 190 ℃~210 ℃, the screw speed is 20 r / min~50 r / min, and the spinneret orifice diameter is 0.2 mm~0.8 mm.

7. The preparation method according to claim 4, characterized in that, In step (2), the cooling operation is as follows: cooling to 25 ℃~40 ℃ via a cooling water tank; The stretching operation is carried out in a stretching machine at a temperature of 80 ℃ to 110 ℃ and a stretching ratio of 5 to 10 times.

8. The preparation method according to claim 4, characterized in that, In step (2), the conditions for the hydrolysis crosslinking reaction are: reaction temperature of 60 ℃~85 ℃, relative humidity of 70 %~90%, and crosslinking time of 2 h~8 h; The hot air drying temperature is 50 ℃~70 ℃, and the drying time is 1 h~3 h; The temperature for the setting process is 100 ℃~120 ℃, and the setting time is 0.5 h~1.5 h.

9. An application of HDPE high abrasion resistant monofilament as described in any one of claims 1 to 3 in the field of protective sleeves.

10. The application according to claim 9, characterized in that, The protective sleeve includes polyethylene braided mesh, heat-shrinkable fabric, heat-shrinkable tubing, and textile tubing, and is used for safety protection of the internal piping system of fuel vehicles and the wiring harness compartment of new energy vehicles.

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