Cable sheath master batch capable of preventing rodent of rats and ants and preparation method of cable sheath master batch

Abstract

The invention discloses a cable sheath master batch capable of preventing rodent of rats and ants and a preparation method of the cable sheath master batch. The cable sheath master batch comprises the following raw materials: 50-70 parts of a modified polyolefin matrix, 10-15 parts of a nano composite filler, 15-25 parts of a slow-release type composition capable of preventing rats and ants and 5-8 parts of a multifunctional additive system, the modified polyolefin matrix is prepared from 40 to 50 parts of polypropylene, 15 to 25 parts of polyethylene and 5 to 10 parts of ethylene propylene diene monomer; the nano composite filler is prepared from 3 to 5 parts of nano titanium dioxide, 3 to 5 parts of nano zinc oxide and 2 to 5 parts of graphene; the multifunctional additive system consists of 2-3 parts of a coupling agent, 1-2 parts of a composite antioxidant and 2-3 parts of an environment-friendly plasticizer. Natural substances such as capsaicin and menthol are compounded to serve as a core repellent, long-acting protection of 18 months or above can be achieved in combination with a chitosan-sodium alginate composite microcapsule slow-release carrier, rats and ants are not prone to generating drug resistance, and the rat and ant prevention time is prolonged by 2-3 times compared with a traditional chemical agent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cable sheath materials, and particularly relates to a cable sheath master batch for preventing rodents and ants from gnawing and a preparation method thereof. BACKGROUND

[0002] In the fields of power and communication, cables are important carriers for transmitting energy and signals, and the performance of cable sheaths, as the outer protective structure of cables, directly affects the service life and safety of cables. However, in actual applications, cables often face the invasion of rodents and ants. The gnawing of rodents and ants can cause damage to cable sheaths, and further damage the conductive core wires inside the cables, leading to short circuits, signal interruptions and other faults, which brings serious safety hazards to power supply and communication transmission.

[0003] At present, the commonly used anti-rodent cable sheaths on the market mainly achieve the function of preventing gnawing by adding chemical agents, such as adding toxic substances such as bromadiolone and rodenticide. Although these chemical agents can prevent rodents and ants to some extent, they have obvious defects. On the one hand, these agents are toxic, not only polluting the environment, but also possibly harming the health of humans and other organisms; on the other hand, after long-term use, rodents and ants may develop resistance to these agents, leading to a gradual decline in the effect of preventing rodents and ants. In addition, the existing anti-rodent cable sheath master batch has poor dispersibility and compatibility of the components during the preparation process, resulting in unsatisfactory mechanical properties and weather resistance of the master batch, which further affects the service life of the cable sheath. SUMMARY

[0004] In view of the problems in the prior art, the present application proposes the following technical solutions:

[0005] The anti-rodent cable sheath master batch and the preparation method thereof comprise the following raw materials in parts by weight: a modified polyolefin matrix 50-70 parts, a nano-composite filler 10-15 parts, a slow-release anti-rodent composition 15-25 parts, and a multifunctional additive system 5-8 parts; the modified polyolefin matrix is composed of polypropylene 40-50 parts, polyethylene 15-25 parts, and ethylene-propylene-diene rubber 5-10 parts; the nano-composite filler is composed of nano-titanium dioxide 3-5 parts, nano-zinc oxide 3-5 parts, and graphene 2-5 parts; and the multifunctional additive system is composed of a coupling agent 2-3 parts, a composite antioxidant 1-2 parts, and an environmentally friendly plasticizer 2-3 parts.

[0006] As a preferred embodiment of the above technical solution, the slow-release anti-rodent composition comprises a core repellent, a slow-release carrier, and a synergist.

[0007] The core repellent is composed of capsaicin 4-6 parts, menthol 3-5 parts, azadirachtin 2-4 parts, and allicin 1-2 parts.

[0008] The slow-release carrier is chitosan-sodium alginate composite microcapsules, the wall material accounts for 30% of the weight, is prepared by emulsification-ion crosslinking method, and has a particle size of 5-10 microns; the synergist is castor oil 5-10 parts.

[0009] As the preferred of the above technical solution, the polypropylene is maleic anhydride grafted polypropylene, and the grafting rate is 1.5-2.0%.

[0010] As the preferred of the above technical solution, the coupling agent is a mixture of silane coupling agent KH-550 and titanate coupling agent TTS at a weight ratio of 60:40, and 0.5-1 parts of Span-80 non-ionic surfactant is added.

[0011] The composite antioxidant is composed of di-t-butyl-p-cresol, triphenyl phosphite and vitamin E acetate at a weight ratio of 2:2:1.

[0012] The environment-friendly plasticizer is composed of epoxidized soybean oil and tributyl citrate at a weight ratio of 60:40.

[0013] The preparation method of the cable sheath master batch for preventing rodents and ants from gnawing comprises the following steps:

[0014] S1, pretreatment microcapsule preparation: chitosan-sodium alginate composite microcapsules are added into 50 DEG C deionized water, the solid-liquid ratio is 1:10, ultrasonic dispersion is carried out for 15 minutes, 0.5 parts of silane coupling agent KH-550 is added for surface hydroxyl modification, and the pretreatment microcapsule is obtained after filtration and drying;

[0015] S2, nano-level dispersion slurry preparation: nano-titanium dioxide, nano-zinc oxide, graphene and Span-80 surfactant are added into a high-speed shearing machine at a rate of 2% of the total weight of the fillers, and are dispersed at 10,000 rpm for 30 minutes to form a nano-level dispersion slurry;

[0016] S3, premix preparation: the modified polyolefin base material is added into a high-speed stirring machine and stirred at 80-100 DEG C for 10-15 minutes, the nano-level dispersion slurry, the pretreatment microcapsule, the composite antioxidant and the environment-friendly plasticizer are sequentially added, and the stirring is continued for 20-30 minutes to obtain the premix;

[0017] S4, melt extrusion and granulation: the premix is added into a double-screw extruder, melt extrusion is carried out at 200-220 DEG C, 0.3-0.5 parts of vulcanizing agent DCP is introduced into the melt section to dynamically vulcanize the ethylene-propylene-diene rubber, three-stage gradient cooling is carried out with the cooling temperature being 80 DEG C→50 DEG C→25 DEG C in sequence, the crystallization rate is controlled, and finally the granulation is carried out to obtain the cable sheath master batch for preventing rodents and ants from gnawing.

[0018] As the preferred technical solution, in S4, the length-diameter ratio of the twin-screw extruder is 36:1, the melting section temperature is 210 DEG C, and the addition amount of the vulcanizing agent DCP is 0.4 parts.

[0019] The beneficial effects of the present application are:

[0020] 1. The present application uses natural substances such as capsaicin and menthol as the core repellent, combined with chitosan-sodium alginate composite microcapsule slow-release carrier, which can achieve long-term protection for more than 18 months, and the termite is not easy to develop drug resistance, which is 2-3 times longer than the traditional chemical rodent control;

[0021] 2. The modified polyolefin matrix is treated by dynamic vulcanization, and the reinforcing effect of the nano composite filler makes the tensile strength of the master batch reach 28-32 MPa, the elongation at break is 450-500%, and the performance retention rate after 1000 hours of ultraviolet aging is 85-92%, which is much better than traditional materials;

[0022] 3. The raw materials of the present application are all environmentally friendly, without toxic chemicals, and the heavy metal content meets the European Union standard; through the optimization of coupling agent and surfactant, the compatibility of each component is improved, the melt flow rate is stable, suitable for cable sheath extrusion molding, and suitable for complex environment use;

[0023] 4. The natural repellent has low cost, the slow-release technology reduces the dosage, the nano filler reduces the resin consumption, and the production cost is reduced by 15-20%; the service life of the cable sheath is extended to 15-20 years, the maintenance and replacement cost is greatly reduced, and the application range is wide. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be described clearly and completely in combination with the embodiments.

[0025] Embodiment 1

[0026] By weight parts:

[0027] Modified polyolefin matrix 50 parts

[0028] Among them, maleic anhydride grafted modified polypropylene 40 parts, grafting rate 1.5%;

[0029] Low-density polyethylene 8 parts, melt flow rate 2.0 g / 10 min, 230 DEG C / 2.16 kg;

[0030] High-density polyethylene 7 parts, melt flow rate 0.8 g / 10 min, 190 DEG C / 2.16 kg;

[0031] Ethylene-propylene-diene rubber 5 parts, ethylene content 50%, Mooney viscosity ML(1+4)125 DEG C 50.

[0032] Nano-composite filler 10 parts

[0033] Nano-titanium dioxide 3 parts, average particle size 20 nm, anatase type;

[0034] Nano-zinc oxide 3 parts, average particle size 30 nm, purity 99.9%;

[0035] Graphene 4 parts, single layer rate 90%, flake diameter 5-10 μm.

[0036] Slow-release rat and ant repellent composition 15 parts

[0037] Core repellent:

[0038] Capsaicin 4 parts, purity 95%;

[0039] Menthol 3 parts, purity 99%;

[0040] Imidacloprid 2 parts, purity 70%;

[0041] Allicin 1 part, purity 80%;

[0042] Slow-release carrier: chitosan-sodium alginate composite microcapsule 4 parts, wall material ratio 30%, particle size 5-8 μm, containing core repellent 10 parts by weight of core material;

[0043] Synergist: castor oil 5 parts, iodine value 85 gI2 / 100 g.

[0044] Multifunctional auxiliary system 5 parts

[0045] Coupling agent:

[0046] Silane coupling agent KH-550: 1.2 parts;

[0047] Titanate coupling agent TTS: 0.8 parts;

[0048] Span-80 nonionic surfactant: 0.5 parts.

[0049] Composite antioxidant:

[0050] Di-tert-butyl-p-cresol (BHT): 0.4 parts;

[0051] Triphenyl phosphite (TPP): 0.4 parts;

[0052] Vitamin E acetate: 0.2 parts.

[0053] Environment-friendly plasticizer:

[0054] Epoxy soybean oil (epoxy value 6.5%): 1.2 parts;

[0055] Tributyl citrate (purity 99%): 0.8 parts.

[0056] Preparation step

[0057] S1: Preparation of pretreated microcapsules

[0058] Take 4 parts of chitosan-sodium alginate composite microcapsules (by weight of core material), add 50℃ deionized water (solid-liquid ratio 1:10), and place in an ultrasonic disperser (power 500W, frequency 25kHz) for 15 minutes to form a uniform suspension.

[0059] Add 0.5 parts of silane coupling agent KH-550 to the suspension, stir at a speed of 300 rpm, and after 30 minutes of reaction, vacuum filter with a Buchner funnel (filter membrane pore size 0.45μm), and place the filter cake in a vacuum drying oven (60℃, -0.09MPa) for 4 hours to obtain pretreated microcapsules for use.

[0060] S2: Preparation of nanoscale dispersion slurry

[0061] Take 3 parts of nanometer titanium dioxide, 3 parts of nanometer zinc oxide, and 4 parts of graphene, mix, and then add 2% of Span-80 surfactant (0.2 parts) based on the total weight, and place in a high-speed shearing machine (model JRJ300-S) with a controlled speed of 10000 rpm and a shearing time of 30 minutes, and control the material temperature ≤40℃ by jacket cooling water during the shearing process to form a nanoscale dispersion slurry (particle size D50 ≤100nm, tested by laser particle size analyzer).

[0062] S3: Preparation of premix

[0063] Add the modified polyolefin matrix raw material (maleic anhydride grafted polypropylene 40 parts, low density polyethylene 8 parts, high density polyethylene 7 parts, and ethylene-propylene-diene rubber 5 parts) to a high-speed stirrer (model GH-10), set the temperature to 80℃, and stir at a speed of 800 rpm for 10 minutes until the surface of the material is slightly melted.

[0064] Add the nanoscale dispersion slurry, pretreated microcapsules, composite antioxidant (BHT 0.4 parts, TPP 0.4 parts, and vitamin E acetate 0.2 parts), and environmentally friendly plasticizer (epoxidized soybean oil 1.2 parts, and tributyl citrate 0.8 parts) in sequence, maintain the temperature at 80℃, and increase the stirring speed to 1200 rpm, and continue stirring for 20 minutes to obtain a uniform premix (observed by optical microscope, no obvious agglomerated particles).

[0065] S4: Melt extrusion and pelletization

[0066] The premix was added to a twin-screw extruder (model SHJ-35, length-diameter ratio 36:1), and the temperature of each zone was set as follows: 160°C for the feeding section, 190°C for the compression section, 210°C for the melting section, 200°C for the homogenization section, and 200°C for the die head.

[0067] The dynamic vulcanization of the EPDM was carried out by adding 0.4 parts of the vulcanizing agent DCP (dicumyl peroxide, purity 99%) through the side feeding port in the melting section (torque maintained at 80-100 N·m).

[0068] After the extruded material was extruded through the die (diameter 3 mm), it entered a three-stage gradient cooling water tank: 80°C for the first stage (length 1 m), 50°C for the second stage (length 1 m), and 25°C for the third stage (length 2 m), with a total cooling time of 30 seconds.

[0069] After cooling, the strip was dried by a blower and then cut into granules (rotating speed 300 rpm) by a granulator to obtain cylindrical master batches with a particle size of 3 mm x 3 mm, which were the products of Example 1.

[0070] Performance testing and result analysis

[0071] Rat-proof performance test (refer to GB / T 2423.17-2008)

[0072] Test environment: temperature 25±2°C, humidity 60±5%, stainless steel test box (100 cm x 50 cm x 50 cm).

[0073] Sample preparation: the master batches were injection molded into test pieces with a size of 100 mm x 50 mm x 2 mm, and there were 3 samples in each group.

[0074] Test object: healthy male hamsters (body weight 150-200 g), 3 in each group, and they were placed in the test box after being starved for 24 hours.

[0075] Result: no obvious bite marks (bite area <5%) were found on the test pieces within 72 hours, and the rodents showed obvious avoidance behavior (residence time <10%) to the test pieces.

[0076] Ant-proof performance test (refer to JT / T 1097-2016)

[0077] Test object: red imported fire ants (workers, 100 in each group), and the rearing temperature was 28±1°C.

[0078] Sample placement: the test pieces were placed in the active area of the ant nest, and observation was conducted for 7 days.

[0079] Result: there was no ant aggregation on the surface of the test pieces, no bite holes (hole number 0), and the repellent rate was >95% (repellent rate = (blank sample bite area - test sample bite area) / blank sample bite area x 100%).

[0080] Mechanical property test (refer to GB / T1040.3-2006)

[0081] Tensile strength: 28.5 MPa (blank polyolefin matrix 22.3 MPa, 27.8% increase).

[0082] Elongation at break: 450% (blank polyolefin matrix 380%, 18.4% increase).

[0083] Shore hardness (A): 85 (blank polyolefin matrix 80, 6.25% increase).

[0084] Sustained-release performance test

[0085] Test method: immerse the test piece in 50 mL of ethanol-water mixture (volume ratio 1:1), constant temperature oscillation (100 rpm) at 30°C, regularly sample and test the concentration of capsaicin (high performance liquid chromatography).

[0086] Results: cumulative release rate of capsaicin within 180 days is 65%, release rate is stable (daily release amount 0.02-0.03 mg / g), no burst release phenomenon (initial 24 hours release rate <10%).

[0087] Weather resistance test (refer to GB / T16422.2-2014)

[0088] Conditions: UV aging box (wavelength 340 nm, irradiance 0.71 W / m 2 , temperature 60°C, relative humidity 50%), aging time 1000 hours.

[0089] Results: tensile strength retention rate 88%, elongation at break retention rate 85%, no obvious decrease in rat and termite resistance (72 hours gnawing area <8%).

[0090] Example 2

[0091] By weight parts:

[0092] Modified polyolefin matrix 60 parts;

[0093] Maleic anhydride grafted modified polypropylene (grafting rate 1.8%): 45 parts;

[0094] Low density polyethylene (melt flow rate 2.5 g / 10 min): 10 parts;

[0095] High density polyethylene (melt flow rate 1.0 g / 10 min): 3 parts;

[0096] Ethylene propylene terpolymer rubber (ethylene content 55%, Mooney viscosity ML(1+4)125°C 60): 2 parts.

[0097] Nano-composite filler 12 parts

[0098] Nano-titanium dioxide (average particle size 15 nm, anatase type) 4 parts

[0099] Nano-zinc oxide (average particle size 25 nm) 4 parts

[0100] Graphene (single layer rate 95%) 4 parts

[0101] Slow-release rat and ant repellent composition 20 parts

[0102] Core repellent

[0103] Capsaicin (purity 95%) 5 parts

[0104] Menthol (purity 99%) 4 parts

[0105] Imidacloprid (purity 70%) 3 parts

[0106] Allicin (purity 80%) 1.5 parts

[0107] Slow-release carrier: chitosan-sodium alginate composite microcapsule (wall material ratio 30%, particle size 7-9 μm) 5.5 parts (containing core repellent 13.5 parts)

[0108] Synergist: castor oil (iodine value 88 g I2 / 100 g) 7 parts

[0109] Multifunctional auxiliary system 6.5 parts

[0110] Coupling agent

[0111] Silane coupling agent KH-550 1.5 parts

[0112] Titanate coupling agent TTS 1.0 part

[0113] Span-80 0.7 parts

[0114] Composite antioxidant

[0115] BHT 0.6 parts

[0116] TPP 0.6 parts

[0117] Vitamin E acetate 0.3 parts

[0118] Environment-friendly plasticizer

[0119] Epoxy soybean oil 1.5 parts

[0120] Tributyl citrate 1.0 part

[0121] Preparation steps

[0122] S1: Preparation of pretreated microcapsules

[0123] Take 5.5 parts of chitosan-sodium alginate composite microcapsules, add 50℃ deionized water (solid-liquid ratio 1:10), ultrasonic dispersion (power 600W, 25kHz) for 15 minutes, add 0.5 parts of KH-550, stir at 300rpm for 30 minutes, filter and vacuum dry at 60℃ for 5 hours, and reserve.

[0124] S2: Preparation of nanoscale dispersion slurry

[0125] Mix 4 parts of nanometer titanium dioxide, 4 parts of nanometer zinc oxide, and 4 parts of graphene, add 2% of Span-80 (0.24 parts) based on the total weight, high-speed shear (10000rpm, 30 minutes), control the temperature ≤40℃, and the slurry particle size D50 ≤90nm.

[0126] S3: Preparation of premix

[0127] Add the modified polyolefin matrix to a high-speed blender, stir at 90℃ and 800rpm for 12 minutes, add the nanoscale slurry, pretreated microcapsules, composite antioxidant, and environmentally friendly plasticizer in sequence, stir at 1200rpm for 25 minutes, and obtain a uniform premix.

[0128] S4: Melt extrusion and pelletization

[0129] Double screw extruder parameters: length-diameter ratio 36:1, feeding section 165℃, compression section 195℃, melting section 210℃, homogenization section 205℃, and die head 205℃.

[0130] Add 0.4 parts of DCP to the melting section and dynamically vulcanize (torque 90-110N·m).

[0131] Three-stage cooling: 80℃→50℃→25℃, pellet size 3mm×3mm, and obtain the product of Example 2.

[0132] Performance testing and result analysis

[0133] Rat resistance performance: the gnawing area of the test piece is <3% in 72 hours, and the rat avoidance rate is >90% (residence time <8%).

[0134] Ant performance: no ant aggregation within 7 days, repellent rate 98%, and no holes in the test piece.

[0135] Mechanical properties:

[0136] Tensile strength: 30.2MPa (increased by 35.4% compared to the blank).

[0137] Elongation at break: 480% (increased by 26.3% compared to the blank).

[0138] Shore hardness (A): 87 (blank raised by 8.75%).

[0139] Sustained release performance: cumulative capsaicin release rate of 62% for 180 days, average daily release of 0.025 mg / g, no burst release.

[0140] Weather resistance: after 1000 hours of ultraviolet aging, the tensile strength retention rate was 90%, the elongation at break retention rate was 88%, and the rat and termite resistance performance was stable (gnawing area <6%).

[0141] Thermal stability (TGA test): 5% thermal weight loss temperature 385°C (blank polyolefin matrix 360°C, raised by 6.9%), 800°C carbon residue rate 12% (blank 8%, raised by 50%).

[0142] Example 3

[0143] By weight parts:

[0144] Modified polyolefin matrix 70 parts:

[0145] Maleic anhydride grafted modified polypropylene (grafting rate 2.0%): 50 parts;

[0146] Low-density polyethylene (melt flow rate 3.0 g / 10 min): 12 parts;

[0147] High-density polyethylene (melt flow rate 1.2 g / 10 min): 5 parts;

[0148] Ethylene-propylene-diene rubber (ethylene content 60%, Mooney viscosity ML (1+4) 125°C 70): 3 parts.

[0149] Nanocomposite filler 15 parts:

[0150] Nanometer titanium dioxide (average particle size 10 nm): 5 parts;

[0151] Nanometer zinc oxide (average particle size 20 nm): 5 parts;

[0152] Graphene (single layer rate 98%): 5 parts,

[0153] Sustained-release rat and termite prevention composition 25 parts:

[0154] Core repellent:

[0155] Capsaicin: 6 parts;

[0156] Menthol: 5 parts;

[0157] Imidacloprid: 4 parts;

[0158] Allicin: 2 parts.

[0159] Slow release carrier: Chitosan-sodium alginate composite microcapsule (wall material 30%, particle size 8-10 μm): 7 parts (containing core repellent 17 parts);

[0160] Synergist: castor oil: 10 parts.

[0161] Multifunctional auxiliary system 8 parts:

[0162] Coupling agent:

[0163] KH-550: 1.8 parts;

[0164] TTS: 1.2 parts;

[0165] Span-80: 1.0 parts.

[0166] Composite antioxidant:

[0167] BHT: 0.8 parts;

[0168] TPP: 0.8 parts;

[0169] Vitamin E acetate: 0.4 parts.

[0170] Environment-friendly plasticizer:

[0171] Epoxidized soybean oil: 1.8 parts;

[0172] Tributyl citrate: 1.2 parts.

[0173] Preparation steps

[0174] S1: Preparation of pretreated microcapsules

[0175] 7 parts of microcapsules were added to 50°C deionized water (1:10), ultrasonic (700W, 25kHz) for 15 minutes, 0.5 parts of KH-550 was added, stirred at 300 rpm for 30 minutes, filtered and vacuum dried at 60°C for 6 hours.

[0176] S2: Preparation of nanoscale dispersion slurry

[0177] Mix 5 parts of nano-titanium dioxide, 5 parts of nano-zinc oxide and 5 parts of graphene, add 2% Span-80 (0.3 parts), shear at 10000 rpm for 30 minutes, and the particle size of the slurry is D50≤80 nm.

[0178] S3: Preparation of premix

[0179] Add modified polyolefin matrix to a high-speed blender, stir at 100°C and 800 rpm for 15 minutes, then add nanoslurry, pretreated microcapsules, composite antioxidant and environment-friendly plasticizer in sequence, and stir at 1200 rpm for 30 minutes.

[0180] S4: Melt extrusion and pelletization

[0181] Twin screw extruder: L / D 36:1, feed zone 170°C, compression zone 200°C, melt zone 210°C, homogenization zone 210°C, die 210°C.

[0182] Add 0.4 parts of DCP in the melt zone, dynamic vulcanization (torque 100-120 N.m).

[0183] After three-stage cooling, cut into pellets to obtain the product of Example 3.

[0184] Performance test and result analysis

[0185] Rat resistance: no gnawing (area <2%) for 72 hours, rat avoidance rate >95%.

[0186] Ant performance: 7-day repellency rate 100%, no ant traces on the surface of the test piece.

[0187] Mechanical properties:

[0188] Tensile strength: 32.0 MPa (43.5% increase over the blank).

[0189] Elongation at break: 500% (31.6% increase over the blank).

[0190] Shore hardness (A): 89 (11.25% increase over the blank).

[0191] Slow-release performance: cumulative release rate of capsaicin 60% in 180 days, average daily release 0.028 mg / g, smooth release curve.

[0192] Weather resistance: after 1000 hours of ultraviolet aging, the tensile strength retention rate is 92%, the elongation at break retention rate is 90%, and the rat and ant resistance effect does not decay.

[0193] Chemical resistance: after immersion in 5% hydrochloric acid and 5% sodium hydroxide solution (25°C, 7 days), the tensile strength retention rate is >90%, and the rat and ant resistance performance remains unchanged.

[0194] Comparative Example 1

[0195] By weight parts:

[0196] Polyolefin matrix 60 parts, bromadiolone 0.5 parts, warfarin 0.3 parts, talc 10 parts, auxiliary agent 5 parts.

[0197] Performance test results

[0198] Rat and ant resistance performance: gnawing area <5% in the initial 72 hours, but after 30 days, rats and ants develop resistance, and the gnawing area increases to 30%.

[0199] Environmental friendliness: heavy metal content 0.015 mg / kg (exceeding the limit of 0.01 mg / kg of the EU RoHS standard), acute oral toxicity LD50 (mice) = 5 mg / kg (highly toxic).

[0200] Mechanical properties: tensile strength 20.1 MPa, elongation at break 350% (lower than Example 1-3).

[0201] Comparative Example 2

[0202] Formulation (same as Example 2, remove nano-composite filler)

[0203] Performance test results

[0204] Tensile strength: 22.3 MPa (26.1% lower than Example 2).

[0205] Elongation at break: 320% (33.3% lower than Example 2).

[0206] Weather resistance: tensile strength retention rate after 1000 hours of aging 65% (27.8% lower than Example 2).

[0207] Comparative Example 3

[0208] Formulation (same as Example 2, core repellent directly added, no microcapsule used)

[0209] Performance test results

[0210] Sustained-release performance: capsaicin release rate 40% (burst release) in 24 hours, cumulative release rate 90% in 30 days, no repellent effect after 60 days.

[0211] Rat and ant prevention performance: excellent in the initial 72 hours (gnawing area <3%), but the gnawing area rises to 40% after 90 days (failure).

[0212] Comprehensive analysis and conclusion

[0213] Rat and ant prevention effect: Example 1-3 uses natural repellents (capsaicin, menthol, etc.) compounded, combined with chitosan-sodium alginate microcapsule sustained-release, rat and ant prevention time up to 180 days or more, and no drug resistance problem, better than Comparative Example 1 (chemical agent) and Comparative Example 3 (no sustained-release).

[0214] Mechanical properties: nano-composite filler (titanium dioxide, zinc oxide, graphene) synergizes with the matrix, significantly improving tensile strength and toughness, Example 3 has the best performance, better than Comparative Example 2 (no nano-filler).

[0215] Environmental protection: the raw materials of examples 1-3 are all environmentally friendly (natural repellent, epoxy soybean oil plasticizer, etc.), the content of heavy metals is less than 0.005 mg / kg, which meets the EU RoHS and REACH standards, and is better than comparative example 1 (containing highly toxic chemical agents).

[0216] Process adaptability: the dynamic vulcanization (DCP) and three-stage gradient cooling process make the processing performance of the master batch stable, the melt index (230℃ / 2.16kg) is maintained at 5-8g / 10min, which is suitable for cable sheath extrusion molding.

[0217] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it.

Claims

1. The cable sheath masterbatch that is resistant to rats and ants is characterized by: The invention comprises the following raw materials in parts by weight: 50-70 parts of a modified polyolefin matrix, 10-15 parts of a nano-composite filler, 15-25 parts of a sustained-release rat-and-ant-proofing composition, and 5-8 parts of a multifunctional auxiliary agent system; the modified polyolefin matrix is ​​composed of 40-50 parts of polypropylene, 15-25 parts of polyethylene, and 5-10 parts of EPDM rubber; the nano-composite filler is composed of 3-5 parts of nano-titanium dioxide, 3-5 parts of nano-zinc oxide, and 2-5 parts of graphene; and the multifunctional auxiliary agent system is composed of 2-3 parts of a coupling agent, 1-2 parts of a composite antioxidant, and 2-3 parts of an environmentally friendly plasticizer.

2. The cable sheath masterbatch for preventing rats and ants from rodents according to claim 1, characterized in that: The slow-release anti-rat and ant composition comprises a core repellent, a slow-release carrier and a synergist; The core repellent is composed of 4-6 parts of capsaicin, 3-5 parts of menthol, 2-4 parts of azadirachtin, and 1-2 parts of allicin; The sustained-release carrier is a chitosan-sodium alginate composite microcapsule, the wall material accounts for 30% by weight, is prepared by an emulsification-ion crosslinking method, and has a particle size of 5-10 μm; the synergist is 5-10 parts of castor oil.

3. The cable sheath masterbatch for preventing rats and ants from rodents according to claim 1, characterized in that: The polypropylene is maleic anhydride grafted modified polypropylene with a grafting rate of 1.5-2.0%.

4. The cable sheath masterbatch for preventing rats and ants from rodents according to claim 1, characterized in that: The coupling agent is a mixture of silane coupling agent KH-550 and titanate coupling agent TTS in a weight ratio of 60%:40%, and 0.5-1 part of Span-80 nonionic surfactant is added; The composite antioxidant is composed of di-tert-butyl-p-cresol, triphenyl phosphite and vitamin E acetate in a weight ratio of 2:2:1; The environmentally friendly plasticizer consists of epoxidized soybean oil and tributyl citrate in a weight ratio of 60%:40%.

5. The method for preparing the rat and ant-resistant cable sheath masterbatch according to any one of claims 1 to 4, characterized in that: include: S1. Preparation of pretreated microcapsules: chitosan-sodium alginate composite microcapsules were added to 50°C deionized water with a solid-liquid ratio of 1:10, and ultrasonically dispersed for 15 minutes. 0.5 parts of silane coupling agent KH-550 were added to modify the surface hydroxyl groups. The pretreated microcapsules were filtered and dried to obtain the pretreated microcapsules. S2. Preparation of nano-scale dispersed slurry: Add nano-titanium dioxide, nano-zinc oxide, graphene and Span-80 surfactant at a rate of 2% of the total weight of the filler into a high-speed shearing machine and disperse at 10,000 rpm for 30 minutes to form a nano-scale dispersed slurry; S3. Preparation of premix: Add the modified polyolefin matrix raw material into a high-speed mixer and stir at 80-100° C. for 10-15 minutes. Then, add the nano-dispersed slurry, pretreated microcapsules, composite antioxidant and environmentally friendly plasticizer in sequence and continue stirring for 20-30 minutes to obtain a premix; S4, melt extrusion and pelletizing: add the premix into a twin-screw extruder, melt extrude at 200-220°C, introduce 0.3-0.5 parts of vulcanizing agent DCP into the melting section to dynamically vulcanize the EPDM rubber, and undergo three-stage gradient cooling with the cooling temperature being 80°C → 50°C → 25°C in sequence to control the crystallization rate, and finally pelletize to obtain the rat and ant-resistant cable sheath masterbatch.

6. The rat and ant-proof cable sheath masterbatch and its preparation method according to claim 5, characterized in that: In S4, the aspect ratio of the twin-screw extruder was 36:1, the melting zone temperature was 210°C, and the amount of vulcanizing agent DCP added was 0.4 parts.