Insect-proof composite material, preparation method thereof and cable

Abstract

The invention relates to the technical field of wire and cable protection, in particular to an insect-proof composite material, a preparation method thereof and a cable. The preparation method of the insect-resistant composite material comprises the following steps: mixing matrix resin, a cross-linking agent and an insect-resistant agent, and enabling the matrix resin to be subjected to a cross-linking reaction under the action of the cross-linking agent and coat the insect-resistant agent to obtain an insect-resistant cross-linked material; performing crushing treatment at the temperature below the brittle temperature of the insect-proof cross-linked material to obtain insect-proof microcapsules; and mixing the insect-proof microcapsules and the polyolefin resin to obtain the insect-proof composite material. When the insect-proof composite material prepared by the invention is applied to a coating layer of an electric wire and a cable, lasting and stable insect-proof performance can be obtained.

Description

Technical Field

[0001] This application relates to the technical field of wire and cable protection, and particularly to an insect-proof composite material, a preparation method thereof, and a cable. Background Art

[0002] Wires and cables are the main carriers for power transmission. Their laying environments are relatively complex. In dark and humid spaces, pests such as termites often appear. As a widely distributed pest, the gnawing behavior of termites on the cable coating layer will lead to a decline in the insulation performance and waterproof performance of the cable. In severe cases, it may even shorten the service life of the cable, causing significant economic losses.

[0003] Currently, it is mainly to directly add insect repellents to the coating layer of wires and cables to reduce the invasion of pests. However, the dispersibility, heat resistance, and persistence of the insect repellents are poor, resulting in unsatisfactory insect-proof performance of the wires and cables. Summary of the Invention

[0004] Based on this, it is necessary to provide an insect-proof composite material, a preparation method thereof, and a cable to solve the problems such as poor dispersibility, heat resistance, and persistence of the insect repellent.

[0005] The above object of this application is achieved through the following technical solutions:

[0006] In the first aspect of this application, a preparation method of an insect-proof composite material is provided, including the following steps:

[0007] Mix a matrix resin, a cross-linking agent, and an insect repellent, and cause the matrix resin to undergo a cross-linking reaction under the action of the cross-linking agent and coat the insect repellent to obtain an insect-proof cross-linked material;

[0008] Perform a pulverization treatment below the embrittlement temperature of the insect-proof cross-linked material to obtain insect-proof microcapsules;

[0009] Mix the insect-proof microcapsules and a polyolefin resin to obtain the insect-proof composite material.

[0010] In some embodiments, the mass ratio of the matrix resin, the cross-linking agent, and the insect repellent is (75~98.5):(0.5~5):(0.5~20).

[0011] In some embodiments, the matrix resin includes one or more of polyurethane, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, styrene-butadiene-styrene block copolymer, polystyrene-isoprene-styrene block copolymer, and silicone rubber.

[0012] In some embodiments, the cross-linking agent includes one or more of dicumyl peroxide, bis(tert-butylperoxy) diisopropylbenzene, benzoyl peroxide, and diisopropyl peroxydicarbonate.

[0013] In some embodiments, the insect repellent includes one or more of imidacloprid, bifenthrin, avermectin, ivermectin, cypermethrin, pyrethrum, and fenvalerate.

[0014] In some embodiments, the polyolefin resin includes one or more of polyethylene, polypropylene, and polyvinyl chloride.

[0015] In some embodiments, the mass fraction of the insect-repellent microcapsules in the insect-repellent composite material is 1% - 40%.

[0016] In some embodiments, mixing the matrix resin, cross-linking agent, and insect repellent includes the following steps: melt-blending for 6 min - 10 min under the conditions of a temperature of 100°C - 120°C and a rotation speed of 40 r / min - 80 r / min, and compression molding under the conditions of a temperature of 100°C - 120°C and a pressure of 6 MPa - 10 MPa.

[0017] In some embodiments, causing the matrix resin to undergo a cross-linking reaction under the action of the cross-linking agent and coating the insect repellent includes the following steps: cross-linking reaction for 5 min - 30 min under the conditions of a temperature of 180°C - 200°C and a pressure of 6 MPa - 10 MPa.

[0018] In some embodiments, performing a pulverization treatment below the embrittlement temperature of the insect-repellent cross-linked material includes the following steps: pulverizing the insect-repellent cross-linked material to a particle size of 15 μm - 100 μm under the conditions of a temperature ≤ -120°C and a frequency of 40 Hz - 70 Hz, and vacuum drying for 6 h - 12 h under the conditions of a temperature of 60°C - 80°C.

[0019] In some embodiments, mixing the insect-repellent microcapsules and the polyolefin resin includes the following steps: melt-blending for 6 min - 10 min under the conditions of a temperature of 180°C - 220°C and a rotation speed of 40 r / min - 80 r / min.

[0020] In the second aspect of the present application, there is provided an insect-repellent composite material prepared by using the preparation method of the insect-repellent composite material as described above.

[0021] In the third aspect of the present application, there is provided a cable including the insect-repellent composite material as described above.

[0022] The present application has at least the following beneficial effects:

[0023] This application utilizes the cross-linking reaction of the matrix resin under the action of a cross-linking agent to coat the insect repellent, which has a good protective effect on the insect repellent, effectively reducing the volatilization and decomposition of the insect repellent during high-temperature processing, and reducing the loss rate of the insect repellent during application. Crushing treatment is carried out below the embrittlement temperature of the insect-repellent cross-linked material, and finer insect-repellent microcapsules can be obtained, promoting their uniform dispersion in the high-heat-resistant polyolefin resin, thereby enhancing the heat resistance and the persistence of the insect-repellent effect of the composite material. Applying the insect-repellent composite material prepared by this application to the coating layer of wire and cable can obtain a durable and stable insect-repellent performance. In addition, the preparation method provided by this application is simple and easy to implement, the equipment used is simple and easy to obtain, and no organic solvents are used throughout the preparation process, and no waste liquid is generated, fully reflecting the green and environmental protection production concept. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of this application and more comprehensively understand this application and its beneficial effects, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic flow chart of the preparation method of the insect-repellent composite material in some embodiments;

[0026] Figure 2 It is the SEM image of the insect-repellent composite material in Example 2;

[0027] Figure 3 It is the chlorine element distribution result chart of the insect-repellent composite material in Example 2;

[0028] Figure 4 It is the thermogravimetric analysis chart of the products of Examples 1 to 3 and Comparative Examples 1 and 3;

[0029] Figure 5 It is the hardness comparison chart of the insect-repellent composite materials of Examples 1 to 3;

[0030] Figure 6 It is the tensile stress comparison chart of the insect-repellent composite materials of Examples 1 to 3. Detailed Description of the Embodiments

[0031] To facilitate the understanding of this application, the following further detailed description of this application is provided in conjunction with specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of this application more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0033] In this application, the meaning of "and / or" includes any and all combinations of one or more of the related listed items. The meaning of "at least one" is more than one, such as one, two or more. The meaning of "multiple" or "several" is at least two, such as two, three, etc., and the meaning of "multiple layers" is at least two layers, such as two layers, three layers, etc., unless otherwise specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise specifically defined.

[0034] When a numerical range is disclosed in this application, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all sub-ranges subsumed therein.

[0035] If there is no special instruction, all steps of this application can be carried out in sequence or randomly. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out in sequence, or can also include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c) in sequence, or can also include steps (a), (c) and (b), or can also include steps (c), (a) and (b), etc.

[0036] In this application, "above" or "below" both include the number itself. For example, below 1 includes 1.

[0037] The temperature parameter in this application, unless otherwise specifically limited, allows both constant temperature treatment and variation within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuation within a range such as ±5°C, ±4°C, ±3°C, ±2°C, ±1°C is allowed.

[0038] In this application, room temperature refers to indoor temperature, normal temperature or general temperature. Generally speaking, the range of room temperature can be any one of the following temperature ranges: 23°C ± 2°C, 25°C ± 5°C or 20°C ± 5°C.

[0039] In the conventional technology, insect repellents such as imidacloprid are usually directly added to the coating layer of wire and cable. However, the dispersibility of the insect repellent in the coating layer is poor, and the processing temperature of the coating layer is about 200 °C, which easily causes the volatilization and decomposition of the insect repellent, resulting in a decrease in the content of the insect repellent in the coating layer and the deterioration of the insect-proof performance of the wire and cable. At the same time, the laying environment of the wire and cable is complex and will be subjected to destructive effects such as high temperature, ultraviolet radiation, mechanical damage, and chemical erosion. The loss rate of the insect repellent in the coating layer is very fast, resulting in insufficient durability of the insect-proof effect of the wire and cable.

[0040] Based on this, in the first aspect of the present application, a preparation method of an insect-proof composite material is provided to solve the problems of poor dispersibility, heat resistance, and durability of traditional insect repellents.

[0041] Please refer to Figure 1 , which is a schematic flow chart of the preparation method of the insect-proof composite material in an embodiment. As Figure 1 shown, the preparation method of the insect-proof composite material includes the following steps:

[0042] S100: Mix the matrix resin, cross-linking agent, and insect repellent, and make the matrix resin undergo a cross-linking reaction under the action of the cross-linking agent to coat the insect repellent, obtaining an insect-proof cross-linked material;

[0043] S200: Perform a pulverization treatment below the brittle temperature of the insect-proof cross-linked material to obtain insect-proof microcapsules;

[0044] S300: Mix the insect-proof microcapsules and polyolefin resin to obtain an insect-proof composite material.

[0045] In the present application, the brittle temperature refers to the temperature at which the probability of brittle failure of the specimen reaches 50% in the impact test, and can be used to describe the low-temperature mechanical behavior of polymer materials.

[0046] The present application uses the matrix resin to undergo a cross-linking reaction under the action of the cross-linking agent to coat the insect repellent, which has a good protective effect on the insect repellent, effectively reducing the volatilization and decomposition of the insect repellent during high-temperature processing, and reducing the loss rate of the insect repellent during application. Performing a pulverization treatment below the brittle temperature of the insect-proof cross-linked material can obtain insect-proof microcapsules with finer particle sizes, promoting their uniform dispersion in the polyolefin resin with high heat resistance, thereby enhancing the heat resistance and durability of the insect-proof effect of the composite material. Applying the insect-proof composite material prepared by the present application to the coating layer of wire and cable can obtain a durable and stable insect-proof performance. In addition, the preparation method provided by the present application is simple and easy to implement, the equipment used is simple and easy to obtain, and no organic solvents are used throughout the preparation process, and no waste liquid is generated, fully reflecting the green and environmental protection production concept.

[0047] The preparation method of the insect-proof composite material will be described in detail in the following step-by-step manner.

[0048] S100: Mix the matrix resin, crosslinking agent and insect repellent, and make the matrix resin undergo a crosslinking reaction under the action of the crosslinking agent to coat the insect repellent, obtaining an insect-proof crosslinked material.

[0049] In some embodiments, the matrix resin includes one or more of polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), styrene-butadiene-styrene block copolymer (SBS), polystyrene-isoprene-styrene block copolymer (SIS), and silicone rubber. Further, the matrix resin includes one or more of polyurethane (PU) and ethylene-vinyl acetate copolymer (EVA).

[0050] In the traditional technology, the coating layer of wire and cable mostly uses high-hardness polymer materials and is prone to cracking. The materials such as polyurethane (PU) and ethylene-vinyl acetate copolymer (EVA) used in this application have good elasticity and excellent flexibility, so that the insect-proof crosslinked material obtained by crosslinking the matrix resin can protect the insect repellent while adjusting the hardness of the insect-proof composite material, enhancing its flexibility and stress cracking resistance.

[0051] In some embodiments, the crosslinking agent includes peroxide crosslinking agents. Among them, the peroxide crosslinking agents include one or more of dicumyl peroxide (DCP), bis(tert-butylperoxy)diisopropylbenzene (BIPB), benzoyl peroxide (BPO), and diisopropyl peroxydicarbonate (DIPP). Further, the crosslinking agent includes one or more of dicumyl peroxide (DCP) and bis(tert-butylperoxy)diisopropylbenzene (BIPB).

[0052] In some embodiments, the insect repellent includes one or more of imidacloprid, bifenthrin, avermectin, ivermectin, cypermethrin, permethrin, and fenvalerate. Further, the insect repellent includes one or more of imidacloprid, bifenthrin, and avermectin.

[0053] In some embodiments, the mass ratio of the matrix resin, the crosslinking agent, and the insect repellent is (75~98.5):(0.5~5):(0.5~20). As an example, in the above mass ratio, the value corresponding to the matrix resin can be 75, 78, 80, 82, 85, 88, 90, 92, 95, 98, or 98.5, the value corresponding to the crosslinking agent can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, and the value corresponding to the insect repellent can be 0.5, 1, 2, 5, 8, 10, 12, 15, 18, or 20. In some specific examples, the mass ratio of the matrix resin, the crosslinking agent, and the insect repellent can be 75:5:20, 80:2:18, 85:3:12, 90:1:9, or 95:0.5:4.5. Further, the mass ratio of the matrix resin, the crosslinking agent, and the insect repellent is (85~90):(0.5~3):(8~12).

[0054] In some embodiments, mixing the matrix resin, the crosslinking agent, and the insect repellent includes the following steps:

[0055] S110: melt-blend for 6 min to 10 min under the conditions of a temperature of 100°C to 120°C and a rotation speed of 40 r / min to 80 r / min to obtain a first mixture;

[0056] S120: press and form under the conditions of a temperature of 100°C to 120°C and a pressure of 6 MPa to 10 MPa to obtain a preformed sheet.

[0057] It can be understood that the melt-blending temperature in step S110 and the press-forming temperature in step S120 are both above the melting point of the matrix resin and below the crosslinking temperature of the crosslinking agent.

[0058] In some embodiments, in step S110, the melt-blending is carried out in a torque rheometer.

[0059] In some embodiments, in step S110, the melt-blending temperature is 100°C to 120°C, including but not limited to 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C, or 120°C.

[0060] In some embodiments, in step S110, the melt-blending rotation speed is 40 r / min to 80 r / min, including but not limited to 40 r / min, 50 r / min, 60 r / min, 70 r / min, or 80 r / min.

[0061] In some embodiments, in step S110, the melt-blending time is 6 min to 10 min, including but not limited to 6 min, 7 min, 8 min, 9 min, or 10 min.

[0062] In some embodiments, in step S110, after melt blending, the following steps are further included: crushing the first mixture into particles with a particle size of 1 mm to 5 mm. Among them, the method of crushing the first mixture can be shearing or mechanical crushing. Crushing the first mixture is beneficial to the subsequent pressing and forming of the first mixture.

[0063] In some embodiments, in step S120, the pressing and forming is carried out in a flat vulcanizing machine.

[0064] In some embodiments, in step S120, the temperature of the pressing and forming is 100°C to 120°C, including but not limited to 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C.

[0065] In some embodiments, in step S120, the pressure of the pressing and forming is 6 MPa to 10 MPa, including but not limited to 6 MPa, 7 MPa, 8 MPa, 9 MPa or 10 MPa.

[0066] In some embodiments, in step S120, the thickness of the preformed sheet is 0.5 mm to 5 mm, including but not limited to 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0067] In some embodiments, the matrix resin is crosslinked under the action of a crosslinking agent and coated with an insect repellent, including the following steps:

[0068] S130: Crosslink the preformed sheet at a temperature of 180°C to 200°C and a pressure of 6 MPa to 10 MPa for 5 min to 30 min to obtain an insect-repellent crosslinked material.

[0069] It can be understood that the temperature of the crosslinking reaction in step S130 is above the crosslinking temperature of the crosslinking agent.

[0070] In some embodiments, in step S130, the crosslinking reaction is carried out in a flat vulcanizing machine.

[0071] In some embodiments, in step S130, the temperature of the crosslinking reaction is 180°C to 200°C, including but not limited to 180°C, 182°C, 184°C, 186°C, 188°C, 190°C, 192°C, 194°C, 196°C, 198°C or 200°C.

[0072] In some embodiments, in step S130, the pressure of the cross-linking reaction is 6 MPa to 10 MPa, including but not limited to 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa.

[0073] In some embodiments, in step S130, the time of the cross-linking reaction is 5 min to 30 min, including but not limited to 5 min, 10 min, 15 min, 20 min, 25 min, or 30 min.

[0074] In some embodiments, in step S130, after the cross-linking reaction, the following steps are further included: crushing the insect-proof cross-linked material into particles with a particle size of 1 mm to 5 mm. Among them, the method of crushing the insect-proof cross-linked material can be one or more of shearing, mechanical crushing, ball milling, and sand milling. Performing a crushing treatment on the insect-proof cross-linked material is beneficial to the subsequent cryogenic grinding of the insect-proof cross-linked material.

[0075] S200: Performing a grinding treatment below the embrittlement temperature of the insect-proof cross-linked material to obtain insect-proof microcapsules.

[0076] Traditional grinding methods, such as mechanical grinding at room temperature, have poor grinding effects on the insect-proof cross-linked material. Performing cryogenic grinding below the embrittlement temperature of the insect-proof cross-linked material can, on the one hand, increase the brittleness of the material, making it easier to obtain smaller-sized insect-proof microcapsules, increasing the probability that insects bite into the insect-proof microcapsules in the composite material, and achieving a better insect-proof effect. On the other hand, cryogenic grinding can also avoid the problem of heat accumulation caused by friction and collision between components during the grinding process, resulting in too high a temperature and damaging the molecular structure of the insect repellent, thereby ensuring that the insect-proof composite material has a stable insect-proof effect.

[0077] In some embodiments, performing a grinding treatment below the embrittlement temperature of the insect-proof cross-linked material includes the following steps: grinding the insect-proof cross-linked material to a particle size of 15 μm to 100 μm under the conditions of a temperature ≤ -120 °C and a frequency of 40 Hz to 70 Hz, and performing vacuum drying at a temperature of 60 °C to 80 °C for 6 h to 12 h.

[0078] In some embodiments, the grinding treatment is performed in a cryogenic grinder.

[0079] In some embodiments, the particle size of the insect-proof microcapsules is 15 μm to 100 μm, including but not limited to 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm. Further, the particle size of the insect-proof microcapsules is 15 μm to 40 μm.

[0080] In some embodiments, the temperature of the comminution treatment is ≤ -120°C, including but not limited to -120°C, -130°C, -140°C, -150°C, -160°C, -170°C, -180°C, -190°C, -200°C, -210°C, -220°C, -230°C, -240°C or -250°C. Further, the temperature of the comminution treatment is -200°C to -150°C.

[0081] In some embodiments, the frequency of the comminution treatment is 40 Hz to 70 Hz, including but not limited to 40 Hz, 45 Hz, 50 Hz, 55 Hz, 60 Hz, 65 Hz or 70 Hz.

[0082] In some embodiments, the comminution treatment includes the following steps: placing the insect-proof crosslinked material in a zirconia grinding jar, soaking the zirconia grinding jar in liquid nitrogen for 1 h and then placing it in a cryogenic mill, and performing cryogenic comminution at a frequency of 40 Hz to 70 Hz. Among them, the number of cryogenic comminution times is 1 to 5 times; the time for each cryogenic comminution is 1 min to 5 min, including but not limited to 1 min, 2 min, 3 min, 4 min or 5 min; after each cryogenic comminution, the zirconia grinding jar is soaked in liquid nitrogen for 10 min to keep the temperature in the zirconia grinding jar below -120°C.

[0083] The comminution treatment needs to keep the temperature below the embrittlement temperature of the insect-proof crosslinked material. For example, below -120°C, it is easy to absorb water during the comminution process, which affects the uniform dispersion of the insect-proof microcapsules in the polyolefin resin and the exertion of the insect-proof effect. Therefore, vacuum drying is required to fully remove the water vapor in the insect-proof microcapsules, improve the uniform dispersion of the insect-proof microcapsules, and avoid the influence of water vapor on the stable exertion of the insect-proof effect.

[0084] In some embodiments, the temperature of the vacuum drying is 60°C to 80°C, including but not limited to 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C.

[0085] In some embodiments, the time of the vacuum drying is 6 h to 12 h, including but not limited to 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h or 12 h.

[0086] S300: Mix the insect-proof microcapsules and the polyolefin resin to obtain an insect-proof composite material.

[0087] In some embodiments, the polyolefin resin includes one or more of polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC). Among them, the polyethylene can be high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ultra-high molecular weight polyethylene (UHMWPE). Further, the polyolefin resin is high-density polyethylene (HDPE), which has good heat resistance, cold resistance, and chemical stability, and also has high rigidity and toughness. Its hardness, tensile strength, and creep resistance are superior to those of low-density polyethylene (LDPE), and it can further improve the heat resistance of the insect-proof composite material and extend the durability of the insect-proof effect.

[0088] In some embodiments, the mass fraction of the insect-proof microcapsules in the insect-proof composite material is 1% - 40%, including but not limited to 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, or 40%. Further, the mass fraction of the insect-proof microcapsules in the insect-proof composite material is 5% - 20%.

[0089] In some embodiments, mixing the insect-proof microcapsules and the polyolefin resin includes the following steps:

[0090] S310: Melt-blend for 6 min - 10 min under the conditions of a temperature of 180°C - 220°C and a rotation speed of 40 r / min - 80 r / min.

[0091] In some embodiments, in step S310, the melt-blending is carried out in a torque rheometer.

[0092] In some embodiments, in step S310, the melt-blending temperature is 180°C - 220°C, including but not limited to 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, or 220°C.

[0093] In some embodiments, in step S310, the melt-blending rotation speed is 40 r / min - 80 r / min, including but not limited to 40 r / min, 50 r / min, 60 r / min, 70 r / min, or 80 r / min.

[0094] In some embodiments, in step S310, the melt-blending time is 6 min - 10 min, including but not limited to 6 min, 7 min, 8 min, 9 min, or 10 min.

[0095] In some embodiments, in step S310, after the melt-blending, the following steps are further included:

[0096] S320: Compress and mold the second mixture obtained in step S310 under the conditions of a temperature of 180°C to 220°C and a rotation speed of 40 r / min to 80 r / min to obtain the insect-proof composite material.

[0097] In some embodiments, in step S320, the compression molding is carried out in a flat vulcanizing machine.

[0098] In some embodiments, in step S320, the temperature of the compression molding is 180°C to 220°C, including but not limited to 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C or 220°C.

[0099] In some embodiments, in step S320, the pressure of the compression molding is 6 MPa to 10 MPa, including but not limited to 6 MPa, 7 MPa, 8 MPa, 9 MPa or 10 MPa.

[0100] In some embodiments, in step S320, the thickness of the insect-proof composite material is 0.5 mm to 5 mm, including but not limited to 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0101] In the second aspect of the present application, an insect-proof composite material is provided, which is prepared by using the preparation method of the insect-proof composite material as described above.

[0102] In the third aspect of the present application, a cable is provided, which includes the insect-proof composite material as described above.

[0103] In some embodiments, the cable includes a conductor and a coating layer sleeved on the conductor, and the coating layer is made of the insect-proof composite material as described above.

[0104] The following is further described in conjunction with specific examples and comparative examples. For the raw materials involved in the following specific examples and comparative examples, unless otherwise specified, they can all be obtained commercially. For the instruments used, unless otherwise specified, they can all be obtained commercially. For the processes involved, unless otherwise specified, they are all the conventional selections of those skilled in the art.

[0105] Example 1

[0106] The insect-proof composite material of this example is prepared by the following method:

[0107] (1) Using a torque rheometer, ethylene-vinyl acetate copolymer (EVA), dicumyl peroxide (DCP), and imidacloprid (denoted as IMI) were melt-blended at a mass ratio of 89:1:10 under the conditions of 100 °C and 40 r / min for 6 min. After taking out, it was cut into particles with a particle size of 1 mm to 5 mm to obtain the first mixture.

[0108] (2) Using a flat vulcanizing machine, the first mixture was pressed at 100 °C and 6 MPa for 3 min to obtain a preformed sheet with a thickness of 2 mm.

[0109] (3) In a flat vulcanizing machine, the preformed sheet was cross-linked at 180 °C and 6 MPa for 3 min. After taking out, it was cut into particles with a particle size of 1 mm to 5 mm to obtain the cross-linked insect-proof material.

[0110] (4) The cross-linked insect-proof material was loaded into a special zirconia grinding jar. The zirconia grinding jar was soaked in liquid nitrogen for 1 h and then put into a cryogenic mill. It was cryogenically milled at a frequency of 70 Hz. After every 3 min of milling, the zirconia grinding jar needed to be taken out, re-soaked in liquid nitrogen for 10 min and then milled again, repeating 3 times; then using a vacuum oven, it was dried at 60 °C and a vacuum degree of -75 kPa for 6 h to obtain insect-proof microcapsules with a particle size of 15 μm.

[0111] (5) Using a torque rheometer, 5% by mass of the insect-proof microcapsules and high-density polyethylene (HDPE) were melt-blended at 200 °C and 60 r / min for 6 min to obtain the second mixture.

[0112] (6) Using a flat vulcanizing machine, the second mixture was pressed at 200 °C and 6 MPa for 6 min to obtain an insect-proof composite material with a thickness of 2 mm.

[0113] Examples 2 to 7

[0114] The preparation methods of the insect-proof composite materials in Examples 2 to 7 are basically the same as those of the insect-proof composite material in Example 1, and the differences are as follows:

[0115] Example 2: The mass fraction of the insect-proof microcapsules is 10%.

[0116] Example 3: The mass fraction of the insect-proof microcapsules is 20%.

[0117] Example 4: The mass ratio of EVA, DCP, and imidacloprid is 75:5:20.

[0118] Example 5: The mass ratio of EVA, DCP, and imidacloprid is 95:0.5:4.5.

[0119] Example 6: The particle size of the insect - proof microcapsules prepared in step (4) is 30 μm.

[0120] Example 7: The particle size of the insect - proof microcapsules prepared in step (4) is 40 μm.

[0121] Comparative Examples 1 to 4

[0122] The preparation methods of the insect - proof composite materials of Comparative Examples 1 - 4 and the insect - proof composite material of Example 1 are basically the same. The specific differences are as follows:

[0123] Comparative Example 1: HDPE was pressed into a sheet with a thickness of 2 mm as the blank control group.

[0124] Comparative Example 2: Using a torque rheometer, imidacloprid with a mass fraction of 5% and HDPE were melt - blended at 200 °C and 60 r / min for 6 min, and then the obtained mixture was pressed at 200 °C and 6 MPa for 6 min using a flat vulcanizer to obtain an insect - proof composite material with a thickness of 2 mm.

[0125] Comparative Example 3: The sheet cross - linked in step (3) (without being shredded) was used as the insect - proof composite material.

[0126] Comparative Example 4: Without performing the low - temperature grinding in step (4), using a torque rheometer, the insect - proof cross - linked material with a mass fraction of 5% and HDPE were melt - blended at 200 °C and 60 r / min for 6 min, and then the obtained mixture was pressed at 200 °C and 6 MPa for 6 min using a flat vulcanizer to obtain an insect - proof composite material with a thickness of 2 mm.

[0127] Test Example

[0128] The following tests were carried out on the products of each example and each comparative example:

[0129] (1) Morphology analysis: The scanning electron microscope (SEM) was used to characterize the micro - morphology.

[0130] (2) Elemental analysis: The energy - dispersive X - ray spectroscopy (EDS) was used to characterize the distribution of chlorine elements.

[0131] (3) Hardness: The test was carried out with reference to GB / T 2411 - 2008, and the durometer type D was used to characterize the hardness of each product.

[0132] (4) Stress - cracking resistance: The test was carried out with reference to GB / T 1040 - 1 - 2018, and a universal testing machine was used to perform tensile tests on each product to characterize the stress - resistance of each product.

[0133] (5) Thermal stability: The thermal stability of the products of each example and each comparative example was characterized by thermogravimetric analysis (TGA), and the thermal decomposition temperature of each product was recorded.

[0134] (6) Insect prevention effect: It was tested by the experimental population method with reference to GB / T 34016-2017 General Rules for Rodent and Ant-proof Electric Wires and Cables and JB / T10696.9-2011 Test Methods for Mechanical and Physical-Chemical Properties of Electric Wires and Cables - Part 9: Termite Experiment.

[0135] The above test results are shown in Table 1 and Figures 2 to 6 as follows.

[0136] Table 1. Performance test results of insect-proof composite materials

[0137]

[0138] As can be seen from Table 1, the insect-proof composite materials prepared in Examples 1 to 7 have the following properties: (1) The particle size of the insect-proof microcapsules obtained by low-temperature grinding is 16 μm to 40 μm, which is beneficial to their uniform dispersion in HDPE; (2) The hardness is 56 HD to 62 HD, and the tensile stress is 17.68 MPa to 18.76 MPa. The hardness is slightly lower than that of the HDPE in Comparative Example 1, but it has better flexibility and improved stress cracking resistance; (3) The thermal decomposition temperature is 370 °C to 385 °C, which is much higher than the thermal decomposition temperature of imidacloprid, effectively preventing the volatilization and decomposition of the insecticide during the cable processing and reducing the loss rate of the insecticide during application; (4) The insect prevention effect is all at level 1, with a persistent and stable insect prevention performance.

[0139] Figure 2 It is the SEM image of the insect-proof composite material of Example 2. As Figure 2 shown, in the insect-proof composite material of Example 2, the structure of the insect-proof microcapsules is complete, the particle size distribution is obvious, showing good microscopic morphological characteristics.

[0140] Figure 3 It is the chlorine element distribution result map of the insect-proof composite material of Example 2. As Figure 3 shown, chlorine elements are significantly enriched and uniformly distributed in the insect-proof composite material of Example 2, and chlorine element is the characteristic element of imidacloprid, indicating that imidacloprid has been successfully incorporated into the insect-proof composite material of Example 2.

[0141] Figure 4 It is the thermogravimetric analysis diagram of the products of Examples 1 to 3 and Comparative Examples 1 and 3. As Figure 4As shown, in Examples 1 to 3, as the mass fraction of the insect-proof microcapsules increases, the thermal stability of the insect-proof composite material slightly decreases, and the thermal decomposition temperature gradually drops; in Comparative Example 3, the sheet obtained by cross-linking in step (3) is used as the insect-proof composite material, without adding HDPE, and its thermal stability decreases significantly, and the thermal decomposition temperature drops to 242 °C, indicating that dispersing the insect-proof microcapsules in HDPE helps to improve the thermal stability of the insect-proof composite material.

[0142] Figure 5 It is a hardness comparison chart of the insect-proof composite materials of Examples 1 to 3. As Figure 5 shown, in Examples 1 to 3, as the mass fraction of the insect-proof microcapsules increases, the hardness of the insect-proof composite material gradually decreases.

[0143] Figure 6 It is a tensile stress comparison chart of the insect-proof composite materials of Examples 1 to 3. As Figure 6 shown, in Examples 1 to 3, as the mass fraction of the insect-proof microcapsules increases, the tensile stress of the insect-proof composite material remains at a level similar to that of the resin matrix.

[0144] Compared with Example 1, the differences in Examples 4 to 5 lie in the weight ratios of the matrix resin, cross-linking agent, and insect repellent in the insect-proof microcapsules. The properties of the obtained insect-proof composite materials are basically the same as those of Example 1. The differences in Examples 6 to 7 lie in the particle size of the insect-proof microcapsules. The properties of the obtained insect-proof composite materials are basically the same as those of Example 1. In addition, the smaller the particle size of the insect-proof microcapsules, the greater the probability that insects and ants bite the insect-proof microcapsules, the greater the probability of the release of the insect repellent, and the better the insect-proof effect. Therefore, the insect-proof and ant-proof effect of Example 1 is more significant in practical applications.

[0145] Compared with Example 1, in Comparative Example 1, no insect-proof microcapsules were added to the HDPE, and it has no insect-proof effect. In Comparative Example 2, the insect repellent was not coated, resulting in a significant decrease in tensile stress and poor stress cracking resistance; at the same time, the insect repellent will quickly lose in the soil, especially in a high-humidity and high-temperature environment, and the loss rate is more significant, resulting in poor long-term effectiveness of the insect repellent and unable to play a role for a long time. Therefore, the insect-proof effect in practical applications is also not ideal. In Comparative Example 3, no HDPE was added, and the hardness, tensile stress, and thermal decomposition temperature of the material all decreased significantly, indicating that dispersing the insect-proof microcapsules in HDPE helps to improve the heat resistance and mechanical properties of the composite material, thereby enhancing the durability of the insect-proof effect. In Comparative Example 4, the insect-proof microcapsules were not cryogenically pulverized, and their particle size was 1 mm to 5 mm, and the dispersion effect in HDPE was poor, resulting in significant deterioration of its hardness, tensile stress, thermal decomposition temperature, and insect-proof effect, indicating that cryogenically pulverizing the insect-proof microcapsules into micron-sized particles is crucial for obtaining a durable and stable insect-proof performance.

[0146] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0147] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for preparing an insect-proof composite material, characterized in that: The following steps are involved: Mixing a base resin, a crosslinking agent and an insect repellent, allowing the base resin to undergo a crosslinking reaction under the action of the crosslinking agent and coat the insect repellent to obtain an insect repellent crosslinked material; Performing a crushing treatment below the brittle temperature of the insect-proof cross-linked material to obtain insect-proof microcapsules; The insect-proof microcapsules and polyolefin resin are mixed to obtain the insect-proof composite material.

2. The method for preparing the insect-proof composite material according to claim 1, characterized in that: The mass ratio of the base resin, the cross-linking agent and the insect repellent is (75-98.5): (0.5-5): (0.5-20).

3. The method for preparing the insect-proof composite material according to claim 2, characterized in that: One or more of the following conditions are met: (1) The matrix resin includes one or more of polyurethane, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, styrene-butadiene-styrene block copolymer, polystyrene-isoprene-styrene block copolymer and silicone rubber; (2) The cross-linking agent includes one or more of diisopropyl peroxide, diisopropyl di-tert-butyl peroxide, benzoyl peroxide and diisopropyl peroxydicarbonate; (3) The insect repellent includes one or more of imidacloprid, bifenthrin, avermectin, ivermectin, cypermethrin, permethrin and cypermethrin; (4) The polyolefin resin includes one or more of polyethylene, polypropylene and polyvinyl chloride.

4. The method for preparing the insect-proof composite material according to claim 3, characterized in that: The mass fraction of the insect-proof microcapsules in the insect-proof composite material is 1% to 40%.

5. The method for preparing the insect-proof composite material according to any one of claims 1 to 4, characterized in that: Mixing the base resin, the crosslinking agent and the insect repellent comprises the following steps: The melt blending is carried out at a temperature of 100°C to 120°C and a rotation speed of 40 r / min to 80 r / min for 6 min to 10 min, and the pressing is carried out at a temperature of 100°C to 120°C and a pressure of 6 MPa to 10 MPa.

6. The method for preparing the insect-proof composite material according to any one of claims 1 to 4, characterized in that: The base resin is made to undergo a cross-linking reaction under the action of the cross-linking agent and to cover the insect repellent, comprising the following steps: The cross-linking reaction is carried out for 5min~30min at a temperature of 180℃~200℃ and a pressure of 6MPa~10MPa.

7. The method for preparing the insect-proof composite material according to any one of claims 1 to 4, characterized in that: The pulverization process is carried out below the brittle temperature of the insect-proof cross-linked material, comprising the following steps: The insect-proof cross-linked material is crushed to a particle size of 15 μm to 100 μm at a temperature of ≤-120° C. and a frequency of 40 Hz to 70 Hz, and vacuum dried at a temperature of 60° C. to 80° C. for 6 h to 12 h.

8. The method for preparing the insect-proof composite material according to any one of claims 1 to 4, characterized in that: Mixing the insect-proof microcapsules and the polyolefin resin comprises the following steps: Melt blending is carried out at a temperature of 180°C to 220°C and a rotation speed of 40r / min to 80r / min for 6min to 10min.

9. An insect-proof composite material, characterized in that: The insect-proof composite material is prepared by the preparation method of any one of claims 1 to 8.

10. A cable, characterized in that: The invention comprises the insect-proof composite material as claimed in claim 9.

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