CN107674444B

CN107674444B - Method for recycling recycled plastic for cable sheath material

Info

Publication number: CN107674444B
Application number: CN201710962996.8A
Authority: CN
Inventors: 陈庆; 曾军堂
Original assignee: Jiaxing Huawei New Energy Co Ltd
Current assignee: Jiaxing Huawei new energy Co., Ltd
Priority date: 2017-10-17
Filing date: 2017-10-17
Publication date: 2020-12-08
Anticipated expiration: 2037-10-17
Also published as: CN107674444A

Abstract

The invention belongs to the technical field of application of recycled plastics, and provides a method for recycling recycled plastics for a cable sheath material. The method comprises the steps of melting the regenerated plastic, homogenizing molecular chains of the regenerated plastic by adopting plasma, reducing viscosity, increasing free volume and enhancing the activity capability of the molecular chains, and then blending the molten regenerated plastic and a rubber body under high pressure with the assistance of a cross-linking agent and a catalyst to enable the freely-moving activated regenerated plastic molecular chains to be cross-linked with the rubber and to be polymerized by self, so as to form the cable sheath material with high strength, high elongation and high softness. Compared with the traditional method, the method overcomes the defects of low strength and unstable quality of the regenerated plastic in the conventional recovery, the obtained cable sheath material has high strength, elongation and softness, various service performances are excellent, the whole process is simple and easy to control, the product quality is relatively stable, and the industrial production can be realized.

Description

Method for recycling recycled plastic for cable sheath material

Technical Field

The invention belongs to the technical field of application of recycled plastics, and provides a method for recycling recycled plastics for a cable sheath material.

Background

The plastic industry is one of the prop industries of national economy in China, in recent years, the production and application development of plastic products, the market demand is continuously increased, the application of the plastic products in China is ubiquitous from agricultural production to clothes and food residents, and the plastic wastes are increased. The characteristics of non-putrefaction and non-decomposition become social problems which are noticed by China. Sources of waste plastics can be broadly divided into: firstly, leftover materials generated in the production process of a factory are blanked; secondly, packing materials used by a large material collecting and distributing center; and thirdly, various waste plastics purchased from society. Although some plastics do not directly pollute the environment, the plastics occupy a large amount of space, are difficult to degrade by air or microorganisms due to extremely strong chemical inertness, have great influence on the environment and cause huge waste of resources. Therefore, the research on the recycling of the plastics has very important significance to the economy and the environment and is very slow.

The recycled plastic is an important way for recycling the plastic, and is a plastic raw material obtained by processing the waste plastic through physical or chemical methods such as pretreatment, melting granulation, modification and the like, and is the recycling of the plastic. But the waste plastics have complex varieties and high impurity content, so the performance loss is serious.

The loss of properties of recycled plastics is mainly caused by photoaging, oxidation and thermal aging. The magnitude of the performance degradation depends mainly on the age and the environment. The properties of several common recycled plastics vary as follows: the color change of the regenerated PVC is obvious, the specific viscosity is unchanged for two times, the reduction tendency is realized for more than two times, and a stabilizer is required to be added; the PE is regenerated, the performance is reduced, the color turns yellow, and after multiple times of extrusion, the viscosity of the high-density polyethylene is reduced, and the viscosity of the low-density polyethylene is increased; when the PP is regenerated once, the color is almost unchanged, the melt index is increased, the color is increased more than twice, the melt index is still increased, and the breaking strength and the elongation after regeneration are reduced to some extent; the color of the regenerated PS turns yellow, so the regenerated PS generally undergoes a color difference. The reduction degree of each property of the reclaimed material is in direct proportion to the regeneration times, the breaking strength is not obviously changed when the doping amount is less than 60 percent, and the ultimate viscosity is not obviously changed when the doping amount is less than 40 percent; the color change of the ABS after regeneration is obvious, but the performance is not obviously changed when the doping amount is not more than 20-30%; the regeneration of nylon also has the problems of discoloration and performance reduction, and the addition amount is preferably less than 20%, the regeneration elongation rate is reduced, but the elasticity tends to be increased.

At present, the recycling of the recycled plastics both at home and abroad achieves certain achievements. Ding et al invented a recycled plastic composite reinforced with herb residue, comprising the following components in mass percent: 50-70% of traditional Chinese medicine residues, 20-40% of modified recycled plastic, 2-10% of mineral filler, 2-5% of compatilizer, 1-5% of lubricant, 1-3% of colorant, 1-3% of antioxidant and 1-3% of light stabilizer, and the main processes comprise traditional Chinese medicine residue pretreatment, recycled plastic modification, material mixing process, granulation process, extrusion molding and surface post-treatment. In addition, Zhao et al, a method for preparing a building and packaging template from recycled plastic, comprising the steps of: crushing the plastic waste into fragments with the diameter less than or equal to 1cm to prepare plastic fragments; taking sawdust or breaking branches and branches into wood chips with the diameter of less than or equal to 1 cm; wood chips or sawdust and plastic chips in a weight ratio of 2: 1-1, mixing and stirring; putting the mixture into a mold, placing kraft paper or aluminum plastic films on the upper surface and the lower surface in the mold, heating at 200-400 ℃, pressurizing at 100-200 Mpa, cooling and shaping after 10-30 minutes, and planting edges to prepare a template with the thickness of 1-10 cm. The technical method improves the performance and the use value of the recycled plastic to a certain extent, but still causes unobvious performance improvement effect due to the problems of complicated varieties, more impurities and the like of various waste plastics, and simultaneously has more complicated process and high cost.

Disclosure of Invention

Aiming at the defects of low performance, complex variety and low recycling value of the existing waste plastic, the method for recycling the regenerated plastic for the cable sheath material is provided, and is characterized in that the molecular chain of the regenerated plastic is homogenized by adopting plasma after the regenerated plastic is melted, the viscosity is reduced, the free volume is increased, the activity capability of the molecular chain is enhanced, and then the regenerated plastic is mixed with a rubber body under the assistance of a cross-linking agent and a catalyst at high pressure, so that the freely-moving activated regenerated plastic molecular chain is cross-linked with the rubber and self-polymerized to form the cable sheath material with high strength, high elongation and high softness, the additional value of the regenerated plastic is greatly improved, and the method can be popularized and applied in a. Particularly, the method can solve the problems of complicated varieties, serious performance loss and reduced application value in the process of recycling common waste plastics. Provides a better technical approach for the recycling of the waste plastics.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

a method for recycling cable sheath material from regenerated plastic is characterized in that the molecular chain of the regenerated plastic is homogenized by plasma after being melted, the viscosity is reduced, the free volume is increased, the mobility of the molecular chain is enhanced, and then the molecular chain is mixed with a rubber body under high pressure with the assistance of a cross-linking agent and a catalyst, so that the freely moving activated regenerated plastic molecular chain is cross-linked with rubber and self-polymerized to form the cable sheath material with high strength, high elongation and high softness; the method comprises the following specific steps:

(1) firstly, manually screening waste plastics to remove coarse impurities; then screening by using a magnetic separator, removing impurities of scrap iron and scrap steel and drying; then adding a proper amount of plasticizer, uniformly mixing, adding into a melting tank, and taking molten salt as a heating medium to heat and melt the regenerated plastic; further adopting a radio frequency glow plasma generating device, and treating the melt for 10-20min at a plasma radio frequency of 30-50 MHz and a working current of 120-150 mA under a certain background vacuum and working vacuum to obtain a homogenized melt; molecular chain homogenization, viscosity reduction, free volume increase and molecular chain mobility enhancement of the recycled plastic are realized;

(2) strongly stirring and mixing the homogenized melt obtained in the step (1) and the rubber body uniformly according to a certain mass ratio in a high-pressure reaction kettle, adding an anti-aging agent, applying a high pressure of 1.5-3MPa to the reaction kettle, and maintaining the pressure for 5-15min under the stirring state; then adding a certain amount of cross-linking agent and catalyst, continuing to stir at high pressure for reaction, so that the homogenized melt molecular chain with stronger activity ability is cross-linked with rubber and self-polymerized to form stable macromolecules; and granulating to obtain the cable sheath material with high strength, high elongation and high softness.

Preferably, the magnetic field intensity of the magnetic separator in the step (1) is 1.5-2T, and metal impurities with the particle size of less than 3mm can be screened;

preferably, the plasticizer in the step (1) is dioctyl phthalate, diethyl phthalate or dibutyl phthalate, and the addition amount of the plasticizer is 0.1-0.3% of the mass of the waste plastic;

preferably, the heating temperature in the step (1) is 150-300 ℃, based on the complete melting of the waste plastics;

preferably, the molten salt of step (1) is an alkali metal or alkaline earth metal halide, silicate or carbonate, such as sodium chloride, magnesium bromide, potassium silicate or sodium carbonate;

preferably, the background vacuum of the plasma treatment in the step (1) is 7-12 Pa, and the working vacuum is 7-14 Pa;

preferably, the rubber body in the step (2) is ethylene propylene diene monomer or styrene butadiene rubber, and the mixing mass ratio of the ethylene propylene diene monomer or styrene butadiene rubber to the homogenized melt is 1: 3-1: 2;

preferably, the anti-aging agent in the step (2) is N-phenyl-N '-isopropyl-p-phenylenediamine or N-N' -diphenyl-p-phenylenediamine, and the addition amount of the anti-aging agent is 1-3% of the mass amount of the mixture of the homogenized melt and the rubber body;

preferably, the crosslinking agent in the step (2) is benzoyl peroxide, dicumyl peroxide or dicumyl peroxide, and the addition amount of the crosslinking agent is 5-8% of the mass of the mixture of the homogenized melt and the rubber body;

preferably, the catalyst in the step (2) is zinc nitrate, aluminum sulfate or aluminum chloride, and the addition amount of the catalyst is 0.5-1% of the mass of the mixture of the homogenized melt and the rubber body.

The plasma has atomic processes of electron collision excitation and de-excitation, light excitation and spontaneous radiative decay, electron collision ionization and multi-body recombination, and molecular processes of molecular dissociation, group replacement, charged particle neutralization, charge exchange decomposition and the like. These processes can produce free radical excited state atoms and molecules, metastable atoms and molecules, and are therefore susceptible to chemical reactions. When the plasma is adopted to treat and regenerate plastic melt, a large amount of plasma particle ozone is generated to directly or indirectly react with plastic molecular chains, so that carbonyl and nitrogen-containing groups are generated on the molecular chains, the polar groups have strong reaction activity, and the molecular chains generate crosslinking and permanent polarization charges. After the regenerated plastic is subjected to plasma activation treatment, molecular chains are homogenized, the viscosity is reduced, the free volume is increased, the mobility is enhanced due to the homogenization of the molecular chains, the molecular chains are intertwined under the action of high pressure after being mixed with a rubber body, self-polymerization is carried out under the action of a catalyst, cross-linking is carried out under the action of a cross-linking agent, the molecular chains and the rubber body are mutually fused at the molecular layer surface to generate a new high molecular chain, and the obtained material has higher strength, extensibility and flexibility and meets the use performance requirement of a cable sheath.

The invention provides a method for recycling a cable sheath material by using recycled plastic, which has the outstanding characteristics and excellent effects compared with the prior art:

1. the method for recycling the waste plastics has the advantages that the waste plastics are activated by the plasmas, so that the molecular chains are homogenized, the homogenization of the molecular chains reduces the viscosity, increases the free volume and enhances the mobility, and the cable sheath material mixed with the rubber body has higher strength, elongation and softness, and is suitable for manufacturing the cable sheath.

2. The method for recycling the recycled plastic overcomes the defects of low strength and poor uniformity of the recycled plastic in the conventional recycling. By virtue of the rubber body, the molecular chain of the homogenized melt is crosslinked with rubber and self-polymerized to form stable macromolecules.

3. The method has the advantages of simple process, easy control, stable and reliable product quality, realization of industrial production and great improvement of the recovery value of the waste plastics.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.

Example 1

A method for recycling recycled plastic for a cable sheath material comprises the following specific steps of:

the waste plastics are manually screened to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 2T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.02kg of dioctyl phthalate, uniformly mixing, adding into a melting tank, and taking sodium chloride as a heating medium to heat and melt the regenerated plastic. Then, a radio frequency glow plasma generating device is adopted, the melt is processed for 10min at the radio frequency of 50MHz under the background vacuum of 7Pa, the working vacuum of 14Pa and the current of 150mA, so that the regenerated plastic forms a homogenized melt, the molecular chain is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; stirring and mixing 10kg of homogenized melt and 4kg of ethylene propylene diene monomer rubber in a high-pressure reaction kettle, adding 0.25kg of N-phenyl-N' -isopropyl-p-phenylenediamine, applying a high pressure of 3MPa to the reaction kettle, and maintaining the pressure for 5min under the stirring state. Then 0.9kg of dicumyl peroxide and 0.1kg of zinc nitrate are added, the high-pressure stirring reaction is continued for 1 hour, the regenerated plastic molecular chain with stronger activity is crosslinked with rubber and self-polymerized to form stable macromolecules, and the cable sheath material with high strength, high elongation and high softness can be obtained after granulation.

The tensile strength, elongation and shore hardness of the cable sheath material obtained in example 1 were measured, and compared with those obtained by recycling recycled plastics by a conventional method, the obtained data are shown in table 1. Therefore, the preparation method of the invention homogenizes and activates the regenerated plastic molecular chain through the plasma, and then carries out crosslinking and self-polymerization with the rubber body, so that the formed novel macromolecular material has higher strength, extensibility and softness and excellent comprehensive performance.

Example 2

the waste plastics are manually screened to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 1.5T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.03kg of diethyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by taking magnesium bromide as a heating medium. Then, a radio frequency glow plasma generating device is adopted to treat the melt for 20min at the radio frequency of 30MHz under the background vacuum of 7Pa, the working vacuum of 8Pa and the current of 120mA, so that the molecular chain of the regenerated plastic is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; stirring and mixing 10kg of homogenized melt and 3.8kg of styrene butadiene rubber in a high-pressure reaction kettle, adding 0.25kg of N-N' -diphenyl-p-phenylenediamine, applying 2MPa of high pressure to the reaction kettle, and maintaining the pressure for 10min under the stirring state. Then adding 0.85kg of benzoyl peroxide and 0.1kg of aluminum chloride, continuing stirring at high pressure for reaction for 1 hour, enabling the regenerated plastic molecular chain with stronger activity to be crosslinked with rubber and self-polymerized to form stable macromolecules, and granulating to obtain the cable sheath material with high strength, high elongation and high softness.

The tensile strength, elongation and shore hardness of the cable sheath material obtained in example 2 were measured, and compared with those obtained by recycling recycled plastics by a conventional method, the obtained data are shown in table 1. Therefore, the preparation method of the invention homogenizes and activates the regenerated plastic molecular chain through the plasma, and then carries out crosslinking and self-polymerization with the rubber body, so that the formed novel macromolecular material has higher strength, extensibility and softness and excellent comprehensive performance.

Example 3

the waste plastics are manually screened to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 1.8T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.01kg of dibutyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by taking potassium silicate as a heating medium. Then, a radio frequency glow plasma generating device is adopted, and the melt is processed for 15min at the radio frequency of 40MHz under the background vacuum of 8Pa, the working vacuum of 12Pa and the current of 130mA, so that the molecular chain of the regenerated plastic is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; stirring and mixing 10kg of homogenized melt and 3.5kg of ethylene propylene diene monomer rubber in a high-pressure reaction kettle, adding 0.25kg of N-N' -diphenyl-p-phenylenediamine, applying a high pressure of 3MPa to the reaction kettle, and maintaining the pressure for 15min under the stirring state. Then adding 0.85kg of dicumyl peroxide and 0.1kg of aluminum chloride, continuing stirring at high pressure for reaction for 30min to enable the regenerated plastic molecular chain with stronger activity to be crosslinked with rubber and to be self-polymerized to form stable macromolecules, and granulating to obtain the cable sheath material with high strength, high elongation and high softness.

The tensile strength, elongation and shore hardness of the cable sheath material obtained in example 3 were measured, and compared with those obtained by recycling recycled plastics by a conventional method, the obtained data are shown in table 1. Therefore, the preparation method of the invention homogenizes and activates the regenerated plastic molecular chain through the plasma, and then carries out crosslinking and self-polymerization with the rubber body, so that the formed novel macromolecular material has higher strength, extensibility and softness and excellent comprehensive performance.

Example 4

the waste plastics are manually screened to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 2T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.02kg of dioctyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by taking sodium carbonate as a heating medium. Then, a radio frequency glow plasma generating device is adopted, and the melt is processed for 20min at the radio frequency of 30MHz under the background vacuum of 10Pa, the working vacuum of 13Pa and the current of 140mA, so that the molecular chain of the regenerated plastic is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; stirring and mixing 10kg of melt and 4kg of styrene butadiene rubber in a high-pressure reaction kettle, adding 0.28kg of N-phenyl-N' -isopropyl-p-phenylenediamine, applying a high pressure of 1.5MPa to the reaction kettle, and maintaining the pressure for 10min under the stirring state. Then adding 0.84kg of benzoyl peroxide and 0.1kg of aluminum sulfate, continuing stirring at high pressure for reaction for 5 hours, enabling the regenerated plastic molecular chain with stronger activity to be crosslinked with rubber and self-polymerized to form stable macromolecules, and granulating to obtain the cable sheath material with high strength, high elongation and high softness.

The tensile strength, elongation and shore hardness of the cable sheath material obtained in example 4 were measured, and compared with those obtained by recycling recycled plastics by a conventional method, the obtained data are shown in table 1. Therefore, the preparation method of the invention homogenizes and activates the regenerated plastic molecular chain through the plasma, and then carries out crosslinking and self-polymerization with the rubber body, so that the formed novel macromolecular material has higher strength, extensibility and softness and excellent comprehensive performance.

Example 5

the waste plastics are manually screened to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 1.5T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.03kg of diethyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by using potassium carbonate as a heating medium. Then, a radio frequency glow plasma generating device is adopted, and the melt is processed for 20min at the radio frequency of 50MHz under the background vacuum of 7Pa, the working vacuum of 9Pa and the current of 150mA, so that the molecular chain of the regenerated plastic is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; stirring and mixing 10kg of melt and 4kg of styrene butadiene rubber in a high-pressure reaction kettle with strong force, adding 0.3kg of N-N' -diphenyl-p-phenylenediamine, applying 2MPa of high pressure to the reaction kettle, and maintaining the pressure for 5min under the stirring state. Then adding 0.9kg of benzoyl peroxide and 0.095kg of zinc nitrate, continuing stirring at high pressure for reaction for 1h to enable regenerated plastic molecular chains with stronger activity to be crosslinked with rubber and to be self-polymerized to form stable macromolecules, and granulating to obtain the cable sheath material with high strength, high elongation and high softness.

The tensile strength, elongation and shore hardness of the cable sheath material obtained in example 5 were measured, and compared with those obtained by recycling recycled plastics by a conventional method, the obtained data are shown in table 1. Therefore, the preparation method of the invention homogenizes and activates the regenerated plastic molecular chain through the plasma, and then carries out crosslinking and self-polymerization with the rubber body, so that the formed novel macromolecular material has higher strength, extensibility and softness and excellent comprehensive performance.

Comparative example 1

the same batch of waste plastics as in example 5 was selected and the waste plastics were first screened by hand to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 1.5T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.03kg of diethyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by using potassium carbonate as a heating medium. Stirring and mixing 10kg of melt and 4kg of styrene butadiene rubber in a high-pressure reaction kettle with strong force, adding 0.3kg of N-N' -diphenyl-p-phenylenediamine, applying 2MPa of high pressure to the reaction kettle, and maintaining the pressure for 5min under the stirring state. Then 0.9kg of benzoyl peroxide and 0.095kg of zinc nitrate are added, and the mixture is continuously stirred under high pressure for reaction for 1 hour, so that the regenerated plastic molecular chain with stronger activity is crosslinked with rubber and self-polymerized to form the cable sheath material.

The cable sheath material obtained in comparative example 1 was tested for tensile strength, elongation and shore hardness, and the obtained data are shown in table 1.

Comparative example 2

the same batch of waste plastics as in example 5 was selected and the waste plastics were first screened by hand to remove coarse impurities. Then screening by using a magnetic separator under the magnetic field intensity of 1.5T, removing fine impurities such as scrap steel and iron and drying. Taking 10kg of waste plastic, adding 0.03kg of diethyl phthalate, uniformly mixing, adding into a melting tank, and heating and melting the regenerated plastic by using potassium carbonate as a heating medium. Then, a radio frequency glow plasma generating device is adopted, and the melt is processed for 20min at the radio frequency of 50MHz under the background vacuum of 7Pa, the working vacuum of 9Pa and the current of 150mA, so that the molecular chain of the regenerated plastic is homogenized, the viscosity is reduced, the free volume is increased, and the mobility of the molecular chain is enhanced; and (3) stirring and mixing 10kg of melt and 4kg of styrene butadiene rubber in a high-pressure reaction kettle, and granulating to obtain the cable sheath material.

The cable sheath material obtained in comparative example 2 was tested for tensile strength, elongation and shore hardness, and the obtained data are shown in table 1.

Table 1:

through test data analysis, the method utilizes the plasma to activate and treat the waste plastic, homogenizes molecular chains, endows the molecular chains with good reactivity, and forms high-strength and high-stability macromolecules through crosslinking and self-polymerization with rubber bodies. The high-strength high-ductility high-toughness high-ductility low-ductility high-. The comparative example 1 does not homogenize the waste plastics, and even though the subsequent crosslinking and catalytic polymerization are adopted, the molecular chains of the waste plastics cannot be homogenized and activated, so that the crosslinking and catalytic polymerization hardly has effects and the strength is extremely low; in contrast, the waste plastic is homogenized by adopting plasma in the comparative example 2, but subsequent crosslinking and catalytic polymerization are absent, the strength is extremely low, and the feasibility and the remarkable effect of homogenizing and activating the molecular chain of the waste plastic in the crosslinking polymerization are further proved.

Claims

1. A method for recycling cable sheath material from regenerated plastic is characterized in that the molecular chain of the regenerated plastic is homogenized by plasma after being melted, the viscosity is reduced, the free volume is increased, the mobility of the molecular chain is enhanced, and then the molecular chain is mixed with a rubber body under high pressure with the assistance of a cross-linking agent and a catalyst, so that the freely moving activated regenerated plastic molecular chain is cross-linked with rubber and self-polymerized to form the cable sheath material with high strength, high elongation and high softness; the method comprises the following specific steps:

(1) firstly, manually screening waste plastics to remove coarse impurities; then screening by using a magnetic separator, removing impurities of scrap iron and scrap steel and drying; then adding a proper amount of plasticizer, uniformly mixing, adding into a melting tank, and taking molten salt as a heating medium to heat and melt the regenerated plastic; further adopting a radio frequency glow plasma generating device, and treating the melt for 10-20min at a plasma radio frequency of 30-50 MHz and a working current of 120-150 mA under a certain background vacuum and working vacuum to obtain a homogenized melt; molecular chain homogenization, viscosity reduction, free volume increase and molecular chain mobility enhancement of the recycled plastic are realized; the background vacuum of the plasma treatment is 7-12 Pa, and the working vacuum is 7-14 Pa; the plasticizer is dioctyl phthalate, diethyl phthalate or dibutyl phthalate, and the addition amount of the plasticizer is 0.1-0.3% of the mass of the waste plastic;

(2) strongly stirring and mixing the homogenized melt obtained in the step (1) and the rubber body uniformly according to a certain mass ratio in a high-pressure reaction kettle, adding an anti-aging agent, applying a high pressure of 1.5-3MPa to the reaction kettle, and maintaining the pressure for 5-15min under the stirring state; then adding a certain amount of cross-linking agent and catalyst, continuing to stir at high pressure for reaction, so that the homogenized melt molecular chain with stronger activity ability is cross-linked with rubber and self-polymerized to form stable macromolecules; after granulation, the cable sheath material with high strength, high elongation and high softness can be obtained; the cross-linking agent is benzoyl peroxide, dicumyl peroxide or dicumyl peroxide, and the addition amount of the cross-linking agent is 5-8% of the mass of the mixture of the homogenized melt and the rubber body; the catalyst is zinc nitrate, aluminum sulfate or aluminum chloride, and the addition amount of the catalyst is 0.5-1% of the mass of the mixture of the homogenized melt and the rubber body.

2. The method for recycling the cable sheath material by the recycled plastic according to claim 1, wherein the method comprises the following steps: and (2) the magnetic field intensity of the magnetic separator in the step (1) is 1.5-2T.

3. The method for recycling the cable sheath material by the recycled plastic according to claim 1, wherein the method comprises the following steps: the heating temperature in the step (1) is 150-300 ℃, based on the complete melting of the waste plastics.

4. The method for recycling the cable sheath material by the recycled plastic according to claim 1, wherein the method comprises the following steps: the molten salt in the step (1) is halide, silicate or carbonate of alkali metal or alkaline earth metal.

5. The method for recycling the cable sheath material by the recycled plastic according to claim 1, wherein the method comprises the following steps: the rubber body in the step (2) is ethylene propylene diene monomer or styrene butadiene rubber, and the mixing mass ratio of the ethylene propylene diene monomer or styrene butadiene rubber to the homogenized melt is 1: 3-1: 2.

6. The method for recycling the cable sheath material by the recycled plastic according to claim 1, wherein the method comprises the following steps: the anti-aging agent in the step (2) is N-phenyl-N '-isopropyl-p-phenylenediamine or N-N' -diphenyl-p-phenylenediamine, and the addition amount of the anti-aging agent is 1-3% of the mass of the mixture of the homogenized melt and the rubber body.