Degradable plastic for wire clamp and preparation method thereof

Abstract

The invention provides degradable plastic for a wire clamp. The degradable plastic comprises the following raw materials in parts by mass: 40-60 parts of polylactic acid; 20 to 30 parts of poly (butylene succinate); 10 to 20 parts of modified starch and 15 to 25 parts of glass fiber; 5 to 10 parts of a flame retardant; 3-8 parts of a toughening agent; 1-2 parts of a coupling agent; 0.3 to 0.5 part of an antioxidant; the plastic prepared by the invention has relatively high strength, toughness and degradation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, in particular to a plastic material with excellent mechanical properties, heat resistance and degradability, and is particularly suitable for the manufacture of electronic detonator wire clamps. Background Art

[0002] Digital electronic detonator wire clamp (wire card), also known as electronic detonator quick connector, is an important component used to connect electronic detonators to blasting busbars. The outer shell is injection molded with plastic materials such as ABS or PP, with an embedded manganese steel blade. It has high conductivity and mechanical strength and can be laser-coded. It meets the requirements of automated production of digital electronic detonators and can achieve effective connection between electronic detonators and blasting busbars at blasting operations.

[0003] Digital electronic detonator wire clamps are commonly made of engineering plastics such as ABS and PP in traditional manufacturing processes. However, these materials have exposed significant environmental limitations in the full life cycle assessment - their molecular structure is stable, and the degradation cycle in the natural environment can be as long as hundreds of years. Not only does it cause the accumulation of "white pollution", it is more likely to enter the ecosystem in the form of microplastics, causing lasting harm to soil and water bodies.

[0004] With increasingly stringent global environmental regulations and the growing popularity of green blasting concepts, the industry is increasingly in need of new materials that are both environmentally friendly and engineering-ready. While current mainstream biodegradable plastics, such as polylactic acid (PLA), can achieve over 90% biodegradation within 6-12 months under composting conditions and meet international standards such as ASTM D6400, they suffer from inherent drawbacks: insufficient mechanical strength, poor water resistance, and low heat resistance, making them difficult to meet the requirements for electronic detonator clamps. Therefore, the development of materials that combine excellent mechanical properties with biodegradability is urgently needed. Summary of the Invention

[0005] Aiming at the technical problems of insufficient mechanical strength, poor water resistance and low heat resistance of existing wire clamps, the present invention proposes a plastic material for wire clamps with excellent mechanical properties, heat resistance and degradability.

[0006] A biodegradable plastic for a wire clamp, comprising the following raw materials in parts by weight: Polylactic acid (PLA): 40-60 parts; polybutylene succinate (PBSD): 20-30 parts; modified starch: 10-20 parts; glass fiber: 15-25 parts; flame retardant: 5-10 parts; toughening agent: 3-8 parts; coupling agent: 1-2 parts; antioxidant: 0.3-0.5 parts. PLA (PLA) (40-60 parts) serves as the main structural material of the formula. Its unique molecular chain rigidity imparts excellent mechanical properties to the product. This bio-based polyester, derived from renewable resources such as corn and cassava, not only fully complies with the concept of sustainable development and environmental protection, but its unique ester bond structure also ensures that the material will completely biodegrade in composting conditions after its service life, with degradation products remaining solely carbon dioxide and water, leaving zero environmental pollution. Furthermore, to optimize the material's overall performance, PBSD (20-30 parts) is innovatively introduced into the formula as a performance modifier. This biodegradable polyester, with its flexible molecular chain structure, significantly improves the composite's flexibility through molecular plasticization, significantly increasing the product's elongation at break. Its low melt viscosity also effectively improves the blend's processing fluidity. Therefore, polylactic acid, as the bio-based main material, provides excellent mechanical strength and rigidity while ensuring full biodegradability. Polybutylene succinate significantly improves the material's flexibility and processing fluidity, complementing the polylactic acid. Glass fiber, a specially surface-treated fiber, forms a three-dimensional network within the matrix, resulting in remarkable tensile strength and heat deflection temperature, meeting the stringent mechanical and heat resistance requirements of engineering plastics. Flame retardants impart excellent flame retardancy, meeting the safety requirements of electrical applications. Toughening agents effectively enhance impact strength, overcoming the brittleness of polylactic acid. Coupling agents optimize the interfacial bonding between the glass fiber and the matrix, ensuring effective stress transfer. Antioxidants protect the material's thermal stability during processing and use.

[0007] The preparation method of the modified starch is as follows: S1. Raw material pretreatment stage: placing the natural starch raw material in a vacuum drying oven at 55-65° C. for heat treatment for 1.5-2.5 hours, controlling the relative humidity of the system to less than 30%, reducing the moisture content of the starch to 3-5%, and obtaining a dry starch base material; S2. Citric acid catalytic cross-linking modification stage: dispersing the pretreated starch base material in deionized water at a mass ratio of 1:3-1:4, using a reactor equipped with a paddle stirrer to form a uniform suspension at a stirring rate of 350-450 r / min; adding food-grade citric acid in an amount of 8-12% by weight of the dry basis of the starch as a cross-linking catalyst to the suspension, and simultaneously adding sodium hypophosphite in an amount of 0.5-1.5% by weight of the starch as an esterification reaction accelerator; using a 0.1 mol / L HCl solution to accurately adjust the pH of the system to 3.5-4.5, and controlling the ionic strength of the reaction system to 0.05-0.15 mol / L. l / L; react in a constant temperature water bath at 55-65℃ for 1.5-2.5 hours, wash with 75% ethanol solution three times after the reaction, and vacuum dry at 60℃ until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in an ethanol aqueous solution with a volume fraction of 70±5%, with the solid-liquid ratio precisely controlled at 1:4-1:5; add octadecyl glycidyl ether at a dry starch weight of 10-18%, and add tetrabutylammonium bromide at a starch weight of 0.3-0.8% as a phase transfer catalyst; add 1mol / L The pH value of the reaction system was controlled in the range of 8.5-9.5 by using NaOH solution, and the conductivity of the reaction system was maintained at 2.5-3.5 mS / cm; the reaction was carried out at a constant temperature of 65-75°C for 2.5-3.5 hours, and after the reaction, the reaction was washed three times with anhydrous ethanol and dried in a vacuum at 60°C for 12±1 hours to obtain hydrophobic cross-linked starch; S4. β-cyclodextrin molecular inclusion modification stage: the hydrophobic cross-linked starch and β-cyclodextrin (5-8% by weight of starch dry basis) were dispersed in deionized water at 65±2°C at a solid-liquid ratio of 1:6-1:8; octylphenol polyoxyethylene ether (0.1-0.3% by weight of starch) was added as a surfactant; the reaction was carried out at a constant temperature of 65-75°C at a stirring rate of 300±50 r / min for 1.5±0.2 hours; the reaction solution was filtered through a Buchner funnel and dried in a vacuum at 60°C for 24±2 hours to obtain modified starch. Citric acid creates a three-dimensional cross-linked network between starch molecules, providing a rigid backbone for the material. The long alkyl chains (C18) of ODE are grafted onto this cross-linked network via ether bonds, forming a molecular-level hydrophobic barrier. β-CD, through its unique "hydrophilic on the outside, hydrophobic on the inside" structure, encloses the alkyl chains of ODE within its cavity, forming a stable supramolecular structure. This creates a unique "cross-linking-hydrophobic-inclusion" synergistic system. Regarding hydrophobicity and water resistance, the introduction of octadecyl glycidyl ether significantly reduces starch's water absorption, while citric acid cross-linking further reduces water molecule penetration, making the biodegradable plastic more suitable for use in humid environments.In terms of mechanical properties, the addition of β-cyclodextrin reduces starch brittleness and improves flexibility, while citric acid crosslinking enhances rigidity. The two synergistically optimize the tensile strength and elongation at break of the plastic. In terms of processing performance, β-cyclodextrin can act as a compatibilizer, promoting the blending of starch with synthetic polymers (such as PLA and PBS) and improving melt processability.

[0008] Furthermore, the flame retardant is ammonium polyphosphate. This flame retardant system meets the dual requirements of environmental protection and functionality for biodegradable plastics, while maintaining the material's complete biodegradability, providing long-lasting fire safety protection, and its comprehensive performance far exceeds that of traditional flame retardants.

[0009] Furthermore, the toughening agent is maleic anhydride grafted polyolefin elastomer.

[0010] Furthermore, the coupling agent is silane coupling agent KH550.

[0011] Furthermore, the antioxidant is antioxidant 1010.

[0012] A method for preparing a degradable plastic for a wire clamp comprises the following steps: S11 raw material pretreatment: 40-60 parts by mass of polylactic acid and 20-30 parts by mass of polybutylene succinate are vacuum dried at 50-60° C. for 4-6 hours; 10-20 parts by mass of modified starch are dried at 80° C. for 2-3 hours; 15-25 parts by mass of glass fiber are surface treated with 1-2 parts by mass of a silane coupling agent; S12 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 5-10 parts by mass of flame retardant, 3-8 parts by mass of toughening agent and 0.3-0.5 parts by mass of antioxidant; mix at 2000-3000 rpm for 5-10 minutes; S13 melt blending: Add the premix to the main feed port of the twin-screw extruder; add the surface-treated glass fiber from the side feed port; and melt blend at a temperature range of 160-180°C. S14 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S15 injection molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170-190° C.; and the mold temperature is controlled at 40-60° C. to obtain a degradable plastic for a wire clamp.

[0013] Technical effects of the present invention: 1. Polylactic acid (PLA) (40-60 phr) serves as the backbone material of the formulation. Its unique molecular chain rigidity imparts excellent mechanical properties to the product. This bio-based polyester, derived from renewable resources such as corn and cassava, not only fully complies with sustainable environmental principles, but its unique ester bond structure also ensures complete biodegradation in composting conditions at the end of its life, leaving only carbon dioxide and water as degradation products, resulting in zero environmental impact. Furthermore, to optimize the overall performance of the material, polybutylene succinate (PBSD) (20-30 phr) is innovatively incorporated into the formulation as a performance modifier. This biodegradable polyester, with its flexible molecular chain structure, significantly improves the flexibility of the composite through its molecular plasticizing effect, significantly increasing the elongation at break of the product. Furthermore, its low melt viscosity effectively enhances the processing flowability of the blend. Therefore, PLA, as the bio-based backbone material, provides excellent mechanical strength and rigidity while ensuring complete biodegradability. PBSD significantly improves the flexibility and processing flowability of the material, complementing the PLA.

[0014] 2. Glass fiber, a reinforcing phase, forms a three-dimensional network within the matrix. These specially surface-treated fibers significantly enhance the plastic's tensile strength and heat distortion temperature, meeting the stringent mechanical and heat resistance requirements of engineering plastics. Flame retardants impart excellent flame retardancy, ensuring safety in electrical applications. Toughening agents effectively enhance impact strength, overcoming the brittle nature of polylactic acid. Coupling agents optimize the interfacial bonding between the glass fiber and the matrix, ensuring effective stress transfer. Antioxidants protect the material's thermal stability during processing and use.

[0015] 3. The triple-modified starch of this invention represents a significant advancement. Citric acid creates a three-dimensional crosslinked network between starch molecules, providing a rigid backbone for the material. The long alkyl chains (C18) of ODE are grafted onto the crosslinked network via ether bonds, forming a molecular-level hydrophobic barrier. β-CD, with its unique "hydrophilic on the outside, hydrophobic on the inside" structure, encloses the alkyl chains of ODE within its cavity, forming a stable supramolecular structure. This creates a unique "crosslinking-hydrophobic-inclusion" synergistic system. Regarding hydrophobicity and water resistance, the introduction of octadecyl glycidyl ether significantly reduces starch's water absorption, while citric acid crosslinking further reduces water permeation, making the biodegradable plastic more suitable for use in humid environments. Regarding mechanical properties, the addition of β-cyclodextrin reduces starch's brittleness and improves its flexibility, while citric acid crosslinking enhances rigidity. The two synergistically optimize the plastic's tensile strength and elongation at break. Regarding processability, β-cyclodextrin acts as a compatibilizer, facilitating the blending of starch with synthetic polymers (such as PLA and PBS) and improving melt processability. DETAILED DESCRIPTION

[0016] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0019] A biodegradable plastic for a wire clamp, comprising the following raw materials in parts by weight: Polylactic acid (PLA): 40-60 parts; polybutylene succinate (PBSD): 20-30 parts; modified starch: 10-20 parts; glass fiber: 15-25 parts; flame retardant: 5-10 parts; toughening agent: 3-8 parts; coupling agent: 1-2 parts; antioxidant: 0.3-0.5 parts. PLA (PLA) (40-60 parts) serves as the main structural material of the formula. Its unique molecular chain rigidity imparts excellent mechanical properties to the product. This bio-based polyester, derived from renewable resources such as corn and cassava, not only fully complies with the concept of sustainable development and environmental protection, but its unique ester bond structure also ensures that the material will completely biodegrade in composting conditions after its service life, with degradation products remaining solely carbon dioxide and water, leaving zero environmental pollution. Furthermore, to optimize the material's overall performance, PBSD (20-30 parts) is innovatively introduced into the formula as a performance modifier. This biodegradable polyester, with its flexible molecular chain structure, significantly improves the composite's flexibility through molecular plasticization, significantly increasing the product's elongation at break. Its low melt viscosity also effectively improves the blend's processing fluidity. Therefore, polylactic acid, as the bio-based main material, provides excellent mechanical strength and rigidity while ensuring full biodegradability. Polybutylene succinate significantly improves the material's flexibility and processing fluidity, complementing the polylactic acid. Glass fiber, a specially surface-treated fiber, forms a three-dimensional network within the matrix, resulting in remarkable tensile strength and heat deflection temperature, meeting the stringent mechanical and heat resistance requirements of engineering plastics. Flame retardants impart excellent flame retardancy, meeting the safety requirements of electrical applications. Toughening agents effectively enhance impact strength, overcoming the brittleness of polylactic acid. Coupling agents optimize the interfacial bonding between the glass fiber and the matrix, ensuring effective stress transfer. Antioxidants protect the material's thermal stability during processing and use.

[0020] The preparation method of the modified starch is as follows: S1. Raw material pretreatment stage: placing the natural starch raw material in a vacuum drying oven at 55-65° C. for heat treatment for 1.5-2.5 hours, controlling the relative humidity of the system to less than 30%, reducing the moisture content of the starch to 3-5%, and obtaining a dry starch base material; S2. Citric acid catalytic cross-linking modification stage: dispersing the pretreated starch base material in deionized water at a mass ratio of 1:3-1:4, using a reactor equipped with a paddle stirrer to form a uniform suspension at a stirring rate of 350-450 r / min; adding food-grade citric acid in an amount of 8-12% by weight of the dry basis of the starch as a cross-linking catalyst to the suspension, and simultaneously adding sodium hypophosphite in an amount of 0.5-1.5% by weight of the starch as an esterification reaction accelerator; using a 0.1 mol / L HCl solution to accurately adjust the pH of the system to 3.5-4.5, and controlling the ionic strength of the reaction system to 0.05-0.15 mol / L. l / L; react in a constant temperature water bath at 55-65℃ for 1.5-2.5 hours, wash with 75% ethanol solution three times after the reaction, and vacuum dry at 60℃ until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in an ethanol aqueous solution with a volume fraction of 70±5%, with the solid-liquid ratio precisely controlled at 1:4-1:5; add octadecyl glycidyl ether at a dry starch weight of 10-18%, and add tetrabutylammonium bromide at a starch weight of 0.3-0.8% as a phase transfer catalyst; add 1mol / L The pH value of the reaction system was controlled in the range of 8.5-9.5 by using NaOH solution, and the conductivity of the reaction system was maintained at 2.5-3.5 mS / cm; the reaction was carried out at a constant temperature of 65-75°C for 2.5-3.5 hours, and after the reaction, the reaction was washed three times with anhydrous ethanol and dried in a vacuum at 60°C for 12±1 hours to obtain hydrophobic cross-linked starch; S4. β-cyclodextrin molecular inclusion modification stage: the hydrophobic cross-linked starch and β-cyclodextrin (5-8% by weight of starch dry basis) were dispersed in deionized water at 65±2°C at a solid-liquid ratio of 1:6-1:8; octylphenol polyoxyethylene ether (0.1-0.3% by weight of starch) was added as a surfactant; the reaction was carried out at a constant temperature of 65-75°C at a stirring rate of 300±50 r / min for 1.5±0.2 hours; the reaction solution was filtered through a Buchner funnel and dried in a vacuum at 60°C for 24±2 hours to obtain modified starch. Citric acid creates a three-dimensional cross-linked network between starch molecules, providing a rigid backbone for the material. The long alkyl chains (C18) of ODE are grafted onto this cross-linked network via ether bonds, forming a molecular-level hydrophobic barrier. β-CD, through its unique "hydrophilic on the outside, hydrophobic on the inside" structure, encloses the alkyl chains of ODE within its cavity, forming a stable supramolecular structure. This creates a unique "cross-linking-hydrophobic-inclusion" synergistic system. Regarding hydrophobicity and water resistance, the introduction of octadecyl glycidyl ether significantly reduces starch's water absorption, while citric acid cross-linking further reduces water molecule penetration, making the biodegradable plastic more suitable for use in humid environments.In terms of mechanical properties, the addition of β-cyclodextrin reduces starch brittleness and improves flexibility, while citric acid crosslinking enhances rigidity. The two synergistically optimize the tensile strength and elongation at break of the plastic. In terms of processing performance, β-cyclodextrin can act as a compatibilizer, promoting the blending of starch with synthetic polymers (such as PLA and PBS) and improving melt processability.

[0021] Furthermore, the flame retardant is ammonium polyphosphate. This flame retardant system meets the dual requirements of environmental protection and functionality for biodegradable plastics, while maintaining the material's complete biodegradability, providing long-lasting fire safety protection, and its comprehensive performance far exceeds that of traditional flame retardants.

[0022] Furthermore, the toughening agent is maleic anhydride grafted polyolefin elastomer.

[0023] Furthermore, the coupling agent is silane coupling agent KH550.

[0024] Furthermore, the antioxidant is antioxidant 1010.

[0025] A method for preparing a degradable plastic for a wire clamp comprises the following steps: S1 Raw material pretreatment: 40-60 parts by mass of polylactic acid and 20-30 parts by mass of polybutylene succinate are vacuum dried at 50-60° C. for 4-6 hours; 10-20 parts by mass of modified starch are dried at 80° C. for 2-3 hours; 15-25 parts by mass of glass fiber are surface treated with 1-2 parts by mass of a silane coupling agent; S2 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 5-10 parts by mass of flame retardant, 3-8 parts by mass of toughening agent and 0.3-0.5 parts by mass of antioxidant; mix at 2000-3000 rpm for 5-10 minutes; S3 melt blending: Add the premix to the main feed port of the twin-screw extruder; add the surface-treated glass fiber from the side feed port; and melt blend at a temperature range of 160-180°C. S4 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S5 Injection Molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170-190° C.; and the mold temperature is controlled at 40-60° C. to obtain a degradable plastic for a wire clamp. Example

[0026] A biodegradable plastic for a wire clamp, comprising the following raw materials in parts by weight: Polylactic acid: 40 parts; polybutylene succinate: 20 parts; modified starch: 20 parts, glass fiber: 15 parts; ammonium polyphosphate: 5 parts; maleic anhydride grafted polyolefin elastomer: 3 parts; silane coupling agent KH550: 1 part; antioxidant 1010: 0.3 parts; The preparation method of the modified starch is as follows: S1. Raw material pretreatment stage: the natural starch raw material is placed in a vacuum drying oven at 55° C. for heat treatment for 1.5 hours, the relative humidity of the system is controlled to be less than 30%, and the moisture content of the starch is reduced to 5%, thereby obtaining a dry starch base material; S2. Citric acid catalytic cross-linking modification stage: the pretreated starch base material is dispersed in deionized water at a mass ratio of 1:4, and a reactor equipped with a paddle stirrer is used to form a uniform suspension at a stirring rate of 350 r / min; food-grade citric acid of 12% by weight of the dry basis of the starch is added to the suspension as a cross-linking catalyst, and sodium hypophosphite of 1.5% by weight of the starch is added as an esterification reaction accelerator; a 0.1 mol / L HCl solution is used to accurately adjust the pH of the system to 3.5, and the ionic strength of the reaction system is controlled to be 0.15 mol / L. L; react in a constant temperature water bath at 55°C for 1.5 hours, wash three times with 75% ethanol solution after the reaction, and vacuum dry at 60°C until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in a 75% ethanol aqueous solution by volume fraction, with the solid-liquid ratio precisely controlled at 1:4; add octadecyl glycidyl ether at a dry starch weight of 18% and tetrabutylammonium bromide at a starch weight of 0.8% as a phase transfer catalyst; add 1 mol / L The pH value of the reaction system was controlled within the range of 8.5 by using NaOH solution, and the conductivity of the reaction system was maintained at 3.5 mS / cm; the reaction was carried out at a constant temperature of 65°C for 2.5 hours, and after the reaction, the reaction was washed three times with anhydrous ethanol and dried in a vacuum at 60°C for 12 hours to obtain hydrophobic cross-linked starch; S4. β-cyclodextrin molecular inclusion modification stage: the hydrophobic cross-linked starch and β-cyclodextrin (8% by weight of starch dry basis) were dispersed in deionized water at 65°C at a solid-liquid ratio of 1:8; octylphenol polyoxyethylene ether (0.3% by weight of starch) was added as a surfactant; the reaction was carried out at a constant temperature of 65°C at a stirring rate of 300 r / min for 1.5 hours; the reaction solution was filtered through a Buchner funnel and dried in a vacuum at 60°C for 24 hours to obtain modified starch.

[0027] A method for preparing a degradable plastic for a wire clamp comprises the following steps: S1 Raw material pretreatment: 40 parts by mass of polylactic acid and 20 parts by mass of polybutylene succinate were vacuum dried at 55°C for 4 hours; 20 parts by mass of modified starch were dried at 80°C for 2 hours; 15 parts by mass of glass fiber were surface treated with 1 part by mass of silane coupling agent KH550; S2 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 5 parts by mass of ammonium polyphosphate, 3 parts by mass of maleic anhydride grafted polyolefin elastomer and 0.3 parts by mass of antioxidant 1010; mix at 2000-3000 rpm for 5 minutes; S3 melt blending: The premix is ​​added to the main feed port of the twin-screw extruder; the surface-treated glass fiber is added from the side feed port; and melt blending is performed at a temperature range of 160°C; S4 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S5 Injection Molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170° C.; and the mold temperature is controlled at 40° C. to obtain a biodegradable plastic for a wire clamp. Example

[0028] A biodegradable plastic for a wire clamp, comprising the following raw materials in parts by weight: Polylactic acid: 60 parts; polybutylene succinate: 30 parts; modified starch: 15 parts, glass fiber: 25 parts; ammonium polyphosphate: 10 parts; maleic anhydride grafted polyolefin elastomer: 8 parts; silane coupling agent KH550: 2 parts; antioxidant 1010: 0.5 parts; The preparation method of the modified starch is as follows: A method for preparing a biodegradable plastic for a wire clamp comprises the following steps: S1. a raw material pretreatment stage: placing a natural starch raw material in a vacuum drying oven at 65°C for heat treatment for 2.5 hours, controlling the relative humidity of the system to less than 30%, reducing the moisture content of the starch to 3%, and obtaining a dry starch base material; S2. a citric acid catalyzed cross-linking modification stage: dispersing the pretreated starch base material in deionized water at a mass ratio of 1:4, using a reactor equipped with a paddle stirrer to form a uniform suspension at a stirring rate of 450 r / min; adding food-grade citric acid in an amount of 8% by weight of the dry basis of the starch as a cross-linking catalyst to the suspension, and simultaneously adding sodium hypophosphite in an amount of 0.5% by weight of the starch as an esterification reaction accelerator; using a 0.1 mol / L HCl solution to accurately adjust the system pH to 4.5, and controlling the ionic strength of the reaction system to be 0.08 mol / L. / L; react in a constant temperature water bath at 65℃ for 2 hours, wash with 75% ethanol solution 3 times after the reaction, and vacuum dry at 60℃ until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in a 75% ethanol aqueous solution by volume fraction, with the solid-liquid ratio precisely controlled at 1:5; add 10% octadecyl glycidyl ether by weight of the dry basis of starch, and add 0.8% tetrabutylammonium bromide by weight of the starch as a phase transfer catalyst; add 1mol / L The pH value of the reaction system was controlled in the range of 9.5 by using NaOH solution, and the conductivity of the reaction system was maintained at 3.5 mS / cm; the reaction was carried out at a constant temperature of 75°C for 3.5 hours, and after the reaction, the reaction was washed with anhydrous ethanol three times and vacuum dried at 60°C for 12 hours to obtain hydrophobic cross-linked starch; S4. β-cyclodextrin molecular inclusion modification stage: the hydrophobic cross-linked starch and β-cyclodextrin (8% by weight of starch dry basis) were dispersed in deionized water at 65°C at a solid-liquid ratio of 1:8; 0.3% by weight of starch octylphenol polyoxyethylene ether was added as a surfactant; the reaction was carried out at a constant temperature of 65-75°C at a stirring rate of 300 r / min for 1.5 hours; the reaction solution was filtered through a Buchner funnel and vacuum dried at 60°C for 24 hours to obtain modified starch.

[0029] A method for preparing a degradable plastic for a wire clamp comprises the following steps: S1 Raw material pretreatment: 60 parts by mass of polylactic acid and 30 parts by mass of polybutylene succinate were vacuum dried at 55°C for 4 hours; 15 parts by mass of modified starch were dried at 80°C for 2 hours; 25 parts by mass of glass fiber were surface treated with 2 parts by mass of silane coupling agent KH550; S2 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 10 parts by mass of ammonium polyphosphate, 8 parts by mass of maleic anhydride grafted polyolefin elastomer and 0.5 parts by mass of antioxidant 1010; mix at 2000-3000 rpm for 5 minutes; S3 melt blending: The premix is ​​added to the main feed port of the twin-screw extruder; the surface-treated glass fiber is added from the side feed port; and melt blending is performed at a temperature range of 160°C; S4 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S5 Injection Molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170° C.; and the mold temperature is controlled at 40° C. to obtain a biodegradable plastic for a wire clamp. Example

[0030] A biodegradable plastic for a wire clamp, comprising the following raw materials in parts by weight: Polylactic acid: 50 parts; polybutylene succinate: 25 parts; modified starch: 10 parts, glass fiber: 20 parts; ammonium polyphosphate: 8 parts; maleic anhydride grafted polyolefin elastomer: 6 parts; silane coupling agent KH550: 1.5 parts; antioxidant 1010: 0.4 parts; The preparation method of the modified starch is as follows: S1. Raw material pretreatment stage: placing the natural starch raw material in a vacuum drying oven at 60° C. for heat treatment for 2 hours, controlling the relative humidity of the system to less than 30%, reducing the moisture content of the starch to 4%, and obtaining a dry starch base material; S2. Citric acid catalytic cross-linking modification stage: dispersing the pretreated starch base material in deionized water at a mass ratio of 1:3, using a reactor equipped with a paddle stirrer to form a uniform suspension at a stirring rate of 400 r / min; adding food-grade citric acid at a dry basis weight of 9% of the starch as a cross-linking catalyst to the suspension, and adding sodium hypophosphite at a dry basis weight of 0.8% of the starch as an esterification reaction accelerator; using a 0.1 mol / L HCl solution to accurately adjust the system pH to 3.9, and controlling the ionic strength of the reaction system to 0.06 mol / L. L; react in a constant temperature water bath at 60°C for 1.6 hours, wash three times with 75% ethanol solution after the reaction, and vacuum dry at 60°C until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in a 75% ethanol aqueous solution with a solid-liquid ratio precisely controlled at 1:4; add 12% octadecyl glycidyl ether by weight of the dry basis of starch and 0.4% tetrabutylammonium bromide by weight of the starch as a phase transfer catalyst; add 1 mol / L The pH value of the reaction system was controlled in the range of 8.7 by using NaOH solution, and the conductivity of the reaction system was maintained at 2.6 mS / cm; the reaction was carried out at a constant temperature of 66°C for 2.6 hours. After the reaction, the reaction was washed three times with anhydrous ethanol and dried in a vacuum at 60°C for 12 hours to obtain hydrophobic cross-linked starch; S4. β-cyclodextrin molecular inclusion modification stage: the hydrophobic cross-linked starch and β-cyclodextrin (6% by weight of starch dry basis) were dispersed in deionized water at 65°C at a solid-liquid ratio of 1:6; octylphenol polyoxyethylene ether (0.2% by weight of starch) was added as a surfactant; the reaction was carried out at a constant temperature of 66°C with a stirring rate of 300 r / min for 1.5 hours; the reaction solution was filtered through a Buchner funnel and dried in a vacuum at 60°C for 24 hours to obtain modified starch.

[0031] A method for preparing a degradable plastic for a wire clamp comprises the following steps: S1 Raw material pretreatment: 50 parts by mass of polylactic acid and 25 parts by mass of polybutylene succinate were vacuum dried at 55°C for 4 hours; 10 parts by mass of modified starch were dried at 80°C for 2 hours; 20 parts by mass of glass fiber were surface treated with 1.5 parts by mass of silane coupling agent KH550; S2 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 8 parts by mass of ammonium polyphosphate, 6 parts by mass of maleic anhydride grafted polyolefin elastomer and 0.4 parts by mass of antioxidant 1010; mix at 2000-3000 rpm for 5 minutes; S3 melt blending: The premix is ​​added to the main feed port of the twin-screw extruder; the surface-treated glass fiber is added from the side feed port; and melt blending is performed at a temperature range of 160°C; S4 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S5 Injection Molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170° C.; and the mold temperature is controlled at 40° C. to obtain a biodegradable plastic for a wire clamp.

[0032] Mechanical properties and degradation performance tests of the degradable plastic for wire clamps of the present invention: 1. Mechanical properties According to GB / T1040-1979 (1992), the standard sample was placed under constant temperature and humidity conditions for 5 days, and then a tensile test was performed on a universal mechanical testing machine at a tensile rate of 10 mm / min to measure the tensile strength and elongation at break. The experimental results are shown in Table 1.

[0033] Table 1: Mechanical properties of biodegradable plastics for wire clamps Tensile strength (MPa) Elongation at break (%) Example 1 40.06 54.08 Example 2 39.09 53.19 Example 3 39.81 53.69 2. Degradation Performance: A 10 cm thick layer of soil was placed in a beaker with a water activity of 15%. Plastic was dried at 90°C to constant weight and then evenly buried in the soil. The plastic was removed every 20 days, rinsed with distilled water, and then dried at 90°C to constant weight. The weight loss rate was calculated. The experimental results are shown in Table 2.

[0034] Table 2: Degradation properties of biodegradable plastics for wire clamps 60d weight loss rate (%) 100d weight loss rate (%) Example 1 60.71 96.81 Example 2 58.71 95.12 Example 3 59.12 95.36 In summary, the degradable plastic for wire clamps provided by the present invention not only has high tensile strength and good elongation at break, but also has high biodegradability and a short degradation time, and is almost completely degraded within 100 days. The plastic made by the present invention has high strength, toughness and degradation effect.

[0035] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A biodegradable plastic for a wire clamp, characterized in that: Including the following raw materials by weight: Polylactic acid: 40-60 parts; polybutylene succinate: 20-30 parts; modified starch: 10-20 parts; glass fiber: 15-25 parts; flame retardant: 5-10 parts; Toughener: 3-8 parts; Coupling agent: 1-2 parts; Antioxidant: 0.3-0.5 parts; The preparation method of the modified starch is as follows: S1. Raw material pretreatment stage: placing the natural starch raw material in a vacuum drying oven at 55-65°C for heat treatment for 1.5-2.5 hours, controlling the relative humidity of the system to less than 30%, reducing the moisture content of the starch to 3-5%, and obtaining a dry starch base material; S2. Citric acid catalytic cross-linking modification stage: dispersing the pretreated starch base material in deionized water at a mass ratio of 1:3-1:4, using a reactor equipped with a paddle stirrer to form a uniform suspension at a stirring rate of 350-450r / min; adding 8-12% of the dry weight of the starch to the suspension as a cross-linking catalyst, and adding 0.5-1.5% of the weight of the starch as an esterification reaction promoter; using 0.1mol / L HCl solution to accurately adjust the pH of the system to 3.5-4.5, and controlling the ionic strength of the reaction system to 0.05-0.15m ol / L; react in a constant temperature water bath at 55-65℃ for 1.5-2.5 hours, wash with 75% ethanol solution three times after the reaction, and vacuum dry at 60℃ until the moisture content is less than 2% to obtain a cross-linked starch intermediate; S3. Octadecyl glycidyl ether hydrophobic grafting stage: redisperse the cross-linked starch intermediate in an ethanol aqueous solution with a volume fraction of 70±5%, and control the solid-liquid ratio at 1:4-1:5; add octadecyl glycidyl ether at a volume fraction of 10-18% of the dry weight of starch, and at the same time add tetrabutylammonium bromide at a volume fraction of 0.3-0.8% of the starch weight as a phase transfer catalyst; add 1 mol / L NaOH solution dropwise to control the pH in the range of 8.5-9.5, and maintain the conductivity of the reaction system at 2.5-3.5 mS / cm; react at a constant temperature of 65-75℃ for 2.5-3.5 hours, wash with anhydrous ethanol three times after the reaction, and vacuum dry at 60℃ for 12±1 hours to obtain a hydrophobized cross-linked starch; S4. β-cyclodextrin inclusion modification stage: Disperse the hydrophobized cross-linked starch and 5-8% β-cyclodextrin by weight of the starch dry weight in deionized water at 65±2°C at a solid-to-liquid ratio of 1:6-1:8; Octylphenol polyoxyethylene ether (0.1-0.3% by weight of starch) was added as a surfactant; the reaction was carried out at a constant temperature of 65-75° C. and a stirring rate of 300±50 r / min for 1.5±0.2 hours; the reaction solution was filtered through a Buchner funnel and vacuum-dried at 60° C. for 24±2 hours to obtain modified starch.

2. The biodegradable plastic for wire clamp according to claim 1, characterized in that: The flame retardant is ammonium polyphosphate.

3. The biodegradable plastic for wire clamp according to claim 1, characterized in that: The toughening agent is maleic anhydride grafted polyolefin elastomer.

4. The biodegradable plastic for wire clamp according to claim 1, characterized in that: The coupling agent is silane coupling agent KH550.

5. The biodegradable plastic for wire clamp according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

6. A method for preparing a degradable plastic for a wire clamp according to any one of claims 1 to 5, characterized in that: The following steps are involved: S11 raw material pretreatment: 40-60 parts by mass of polylactic acid and 20-30 parts by mass of polybutylene succinate are vacuum dried at 50-60° C. for 4-6 hours; 10-20 parts by mass of modified starch are dried at 80° C. for 2-3 hours; 15-25 parts by mass of glass fiber are surface treated with 1-2 parts by mass of a silane coupling agent; S12 premix preparation: Add the dried PLA, PBS and modified starch to a high-speed mixer; add 5-10 parts by mass of flame retardant, 3-8 parts by mass of toughening agent and 0.3-0.5 parts by mass of antioxidant; mix at 2000-3000 rpm for 5-10 minutes; S13 melt blending: Add the premix to the main feed port of the twin-screw extruder; add the surface-treated glass fiber from the side feed port; and melt blend at a temperature range of 160-180°C. S14 extrusion granulation: The melt was pelletized by water-cooling strands; the pellets were dried at 50°C for 4 hours; S15 injection molding: The dried particles are added into the hopper of an injection molding machine; injection molding is performed at a melting temperature of 170-190° C.; and the mold temperature is controlled at 40-60° C. to obtain a degradable plastic for a wire clamp.