1. The environment-friendly high-strength polyvinyl chloride cable material is characterized by comprising the following raw materials in parts by weight: 90-100 parts of polyvinyl chloride resin, 20-40 parts of plasticizer, 5-10 parts of molybdenum flame-retardant smoke inhibitor, 5-8 parts of heat stabilizer and 20-30 parts of nano kaolin; the heat stabilizer is a porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside.

2. The polyvinyl chloride cable material of claim 1, wherein the molybdenum-based flame retardant smoke suppressant comprises ammonium octamolybdate and/or molybdenum trioxide.

3. The polyvinyl chloride cable material of claim 1, wherein the plasticizer comprises at least one of dioctyl sebacate, dioctyl azelate, and epoxidized fatty acid methyl ester.

4. The polyvinyl chloride cable material of claim 1, further comprising the following raw materials in parts by weight: 0.05-0.1 part of lubricant and 0.05-0.1 part of antioxidant.

5. The polyvinyl chloride cable material according to claim 4, wherein the lubricant comprises at least one of stearic acid, polyethylene wax and oxidized polyethylene.

6. The polyvinyl chloride cable material according to claim 4, wherein the antioxidant comprises at least one of antioxidant 1010, antioxidant 168, antioxidant RD, and antioxidant MB.

7. The polyvinyl chloride cable material according to claim 1, wherein the preparation method of the heat stabilizer comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 5.8-7.2:1:1.8-3.6 into an emulsifier aqueous solution, uniformly mixing, adding potassium persulfate, reacting for 3-4h at 80-90 ℃ under stirring, adding into ethanol, centrifuging, washing and drying the precipitate to obtain a low-crosslinking polymer;

(1.2) adding the low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, uniformly mixing, reacting for 10-15h at 85-95 ℃ under stirring, centrifuging, washing and drying the precipitate to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a calcium chloride solution, stirring and adsorbing for 1-1.5h, centrifuging, drying the precipitate to obtain a carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into an ammonium carbonate solution, stirring and reacting for 1-2h, centrifuging, and drying the precipitate to obtain a carboxyl porous polymer loaded with calcium carbonate;

(1.4) dissolving dicyclohexylcarbodiimide and N-hydroxysuccinimide in dimethylformamide, adding a calcium carbonate-loaded carboxyl porous polymer into the dimethylformamide, uniformly dispersing the mixture, and reacting the mixture for 20 to 24 hours at the temperature of between 20 and 30 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, reacting at 10-30 deg.C for 10-12h under stirring, centrifuging, washing the precipitate, and drying to obtain the heat stabilizer.

8. The polyvinyl chloride cable material according to claim 7, wherein in step (1.2), the mass ratio of the low crosslinked polymer to dimethoxymethane is 1: 0.6-0.8.

9. The polyvinyl chloride cable material according to claim 7, wherein in the step (1.4), the mass ratio of the calcium carbonate-loaded carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1: 0.05-0.10.

10. A process for preparing a polyvinyl chloride cable material according to any one of claims 1 to 9, comprising the steps of: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 110-120 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 40-50 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Background

Polyvinyl chloride (PVC) is one of the most widely used plastics in the world, has low price, excellent corrosion resistance and electrical insulation, particularly flame-retardant and self-extinguishing resistance, so that the PVC has been widely applied to the production of cable materials, has a long-standing significance in the insulation and protection materials of wires and cables, and is widely applied to the insulation and protection materials of various wires and cables. However, polyvinyl chloride also has some disadvantages.

Firstly, due to the structural particularity of polyvinyl chloride, when the polyvinyl chloride is processed under the conditions of high temperature and high shear, the molecular hydrogen chloride is easy to be removed, the degradation and dehydrochlorination reaction of the polyvinyl chloride is catalyzed, the generated hydrogen chloride is used for degrading the catalyzed polyvinyl chloride more quickly, and finally the strength of the polyvinyl chloride is reduced. Therefore, the addition of heat stabilizers is required to improve the stability of polyvinyl chloride in its processing. The commonly used environment-friendly heat stabilizer in the PVC cable material is a calcium-zinc heat stabilizer which has good lubricity and transparency, but Lewis acid zinc chloride can be generated in the action process to catalyze PVC degradation, so that the obvious zinc burning phenomenon exists, the long-term heat stabilization effect is poor, and in addition, the problem of poor compatibility with PVC exists, and the strength of the PVC cable material can be influenced.

Secondly, the polyvinyl chloride has good flame retardant property, the chlorine content of the polyvinyl chloride reaches 56%, the oxygen index can be more than 45%, but due to the addition of a large amount of plasticizers and other auxiliary agents, the polyvinyl chloride cable material has insufficient flame resistance, black smoke (mainly composed of carbon formed by aromatic compounds) can be generated during combustion, a large amount of HCl is released, and the latter can react with water in the atmosphere to form corrosive cloud mist, so that the polyvinyl chloride cable material has great harm to human bodies, and secondary disasters of cable combustion are caused.

Disclosure of Invention

In order to solve the technical problems, the invention provides an environment-friendly high-strength polyvinyl chloride cable material and a preparation method thereof. The heat stabilizer with a special structure is adopted in the invention, the compatibility with polyvinyl chloride is good, the degradation of the PVC cable material in the processing and using processes can be reduced, and the strength of the cable material is improved; meanwhile, the heat stabilizer can also reduce the release of HCl during the combustion of the polyvinyl chloride cable.

The specific technical scheme of the invention is as follows:

an environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 90-100 parts of polyvinyl chloride resin, 20-40 parts of plasticizer, 5-10 parts of molybdenum flame-retardant smoke inhibitor, 5-8 parts of heat stabilizer and 20-30 parts of nano kaolin; the heat stabilizer is a porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside.

The molybdenum-based flame-retardant smoke suppressant can achieve the aim of low smoke generation while not damaging the flame retardance of materials, and is generally thought to be capable of catalyzing polyvinyl chloride to remove HCl by adding the molybdenum-based flame-retardant smoke suppressant into polyvinyl chloride through a Lewis acid mechanism to form trans-polyene, wherein the trans-polyene cannot be cyclized to generate an aromatic structure, and the compounds are main components of smoke, so that the generation amount of combustible gas is effectively reduced, and the flame retardance and smoke suppression are realized through the mode. In the heat stabilizer, the porous polymer can absorb HCl by utilizing the porous structure of the porous polymer, and meanwhile, calcium carbonate loaded in the porous polymer can neutralize the absorbed HCl in time, so that the adsorption capacity of the heat stabilizer on hydrogen chloride is improved, HCl desorption is prevented, and the release amount of corrosive gas of the polyvinyl chloride cable during combustion can be effectively reduced through the synergistic effect between the porous structure and the calcium carbonate.

Besides reducing the release of HCl during cable combustion, the heat stabilizer used in the invention can also play the role of the heat stabilizer in the cable processing and using process, and improve the strength of the polyvinyl chloride cable material, and the action mode comprises the following two aspects:

1) the thiourea on the surface is used for replacing unstable chlorine atoms in a polyvinyl chloride molecular chain, so that the continuous formation of the unstable chlorine atoms and the formation of a large number of conjugated double bonds can be blocked, and the degradation of PVC is slowed down; and after replacing unstable chlorine atoms, thiourea can form covalent connection with PVC molecular chains, and in this way, the heat stabilizer can form crosslinking among the PVC molecular chains, so that the strength of the polyvinyl chloride cable material is improved.

2) By utilizing the synergistic effect between the porous structure and the calcium carbonate loaded in the porous structure, the hydrogen chloride generated in the PVC degradation process can be adsorbed and neutralized, and the hydrogen chloride is prevented from contacting with PVC to catalyze and further degrade; in addition, after replacing the unstable chlorine atoms, thiourea can generate hydrogen chloride, and can also accelerate the degradation of PVC, so that the long-term thermal stability effect is poor.

In addition, the heat stabilizer used in the invention is mainly composed of organic materials, and the calcium carbonate is loaded in an organic carrier, so that the heat stabilizer has better compatibility with polyvinyl chloride, and the strength of the polyvinyl chloride cable material is not influenced by poor compatibility.

Preferably, the molybdenum-based flame-retardant smoke suppressant comprises ammonium octamolybdate and/or molybdenum trioxide.

Preferably, the plasticizer includes at least one of dioctyl sebacate, dioctyl azelate, and epoxidized fatty acid methyl ester.

Preferably, the feed also comprises the following raw materials in parts by weight: 0.05-0.1 part of lubricant and 0.05-0.1 part of antioxidant.

Preferably, the lubricant comprises at least one of stearic acid, polyethylene wax and oxidized polyethylene.

Preferably, the antioxidant comprises at least one of antioxidant 1010, antioxidant 168, antioxidant RD and antioxidant MB.

Preferably, the preparation method of the heat stabilizer comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 5.8-7.2:1:1.8-3.6 into an emulsifier aqueous solution, uniformly mixing, adding potassium persulfate, reacting for 3-4h at 80-90 ℃ under stirring, adding into ethanol, centrifuging, washing and drying the precipitate to obtain a low-crosslinking polymer;

(1.2) adding the low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, uniformly mixing, reacting for 10-15h at 85-95 ℃ under stirring, centrifuging, washing and drying the precipitate to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a calcium chloride solution, stirring and adsorbing for 1-1.5h, centrifuging, drying the precipitate to obtain a carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into an ammonium carbonate solution, stirring and reacting for 1-2h, centrifuging, and drying the precipitate to obtain a carboxyl porous polymer loaded with calcium carbonate;

(1.4) dissolving dicyclohexylcarbodiimide and N-hydroxysuccinimide in dimethylformamide, adding a calcium carbonate-loaded carboxyl porous polymer into the dimethylformamide, uniformly dispersing the mixture, and reacting the mixture for 20 to 24 hours at the temperature of between 20 and 30 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, reacting at 10-30 deg.C for 10-12h under stirring, centrifuging, washing the precipitate, and drying to obtain the heat stabilizer.

The mechanism for preparing the heat stabilizer through the steps is as follows:

in step (1.1), styrene, acrylic acid, and divinylbenzene are subjected to radical polymerization using potassium persulfate as an initiator to form a polymer having a low degree of crosslinking. In the process, carboxyl can be introduced into the porous polymer by the acrylic monomer to provide a binding site for subsequent calcium ions, so that the load capacity of calcium carbonate is improved, the binding strength between the calcium carbonate and the porous polymer is improved, the calcium carbonate is prevented from falling off in the subsequent reaction process of grafting thiourea and the preparation process of a PVC cable material, and the synergistic effect between the calcium carbonate and the porous polymer is ensured; in addition, the carboxyl groups can provide grafting sites for N- (2-aminophenyl) -N-phenylthiourea, so that the thiourea can be grafted to the surface of the porous polymer.

In the step (1.2), under the catalysis of anhydrous ferric chloride, benzene rings in the low-crosslinking polymer and dimethoxymethane are subjected to post-crosslinking Friedel-Crafts alkylation reaction to form the porous polymer with higher heat resistance.

In step (1.3), calcium ions are adsorbed into the pores of the porous polymer and form coordinate bonds with carboxyl groups, followed by formation of calcium carbonate with carbonate ions.

In step (1.4), carboxyl groups on the surface of the porous polymer react with amino groups in the N- (2-aminophenyl) -N-phenylthiourea to graft the thiourea on the surface of the porous polymer.

Preferably, in the step (1.2), the mass ratio of the low-crosslinked polymer to the dimethoxymethane is 1: 0.6-0.8.

Preferably, in the step (1.4), the mass ratio of the calcium carbonate-loaded carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1: 0.05-0.10.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 110-120 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 40-50 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Compared with the prior art, the invention has the following advantages:

(1) the heat stabilizer can replace unstable chlorine atoms in PVC by utilizing thiourea on the surface of the heat stabilizer, reduces the degradation of PVC cable materials in the processing and using processes, and forms covalent crosslinking among PVC molecular chains, thereby improving the strength of the PVC cable materials;

(2) the heat stabilizer can utilize the porous structure and the calcium carbonate loaded in the porous structure to remove HCl generated after the thiourea on the surface replaces unstable chlorine atoms in time, so that the heat stability of the polyvinyl chloride is further improved, and the strength of the PVC cable material is further improved;

(3) the heat stabilizer can reduce the release of HCl during the combustion of the polyvinyl chloride cable by utilizing the porous structure and the calcium carbonate loaded in the porous structure.

Detailed Description

The present invention will be further described with reference to the following examples. The following examples are intended only to illustrate the invention in detail and are not intended to limit the scope of the invention in any way.

Example 1

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 20 parts of dioctyl sebacate, 10 parts of epoxy fatty acid methyl ester, 7.5 parts of molybdenum trioxide, 6.5 parts of heat stabilizer, 25 parts of nano kaolin, 0.08 part of stearic acid and 10100.08 parts of antioxidant.

The heat stabilizer is a porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside, and the preparation method comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 6.5:1:2.5 into a 0.8 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:45mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.4, reacting for 3.5 hours at 85 ℃ under stirring, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinking polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.6g:0.7g:60mL, uniformly mixing, reacting for 12h at 90 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a 5 wt% calcium chloride solution, stirring and adsorbing for 1.5h, centrifuging, drying the precipitate to obtain a carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into a 5 wt% ammonium carbonate solution, stirring and reacting for 1.5h, centrifuging, and drying the precipitate to obtain a carboxyl porous polymer loaded with calcium carbonate;

(1.4) dissolving DCC and NHS in DMF, adding a calcium carbonate-loaded carboxyl porous polymer into the DMF, wherein the mass-to-volume ratio of the DCC to the NHS to the calcium carbonate-loaded carboxyl porous polymer to the DMF is 0.013g:0.08g:1g, uniformly dispersing, and reacting for 22h at 25 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, wherein the mass ratio of the calcium carbonate-loaded carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1:0.08, reacting for 11h at 20 ℃ under stirring, centrifuging, washing the precipitate with ethanol, and drying to obtain the heat stabilizer.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 115 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 45 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Example 2

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 15 parts of dioctyl azelate, 5 parts of dioctyl sebacate, 5 parts of ammonium octamolybdate, 5 parts of heat stabilizer, 20 parts of nano kaolin, 0.05 part of polyethylene wax and 1680.05 parts of antioxidant.

The heat stabilizer is a porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside, and the preparation method comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 5.8:1:3.6 into a 0.6 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:40mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.3, reacting for 4 hours under the condition of stirring at 80 ℃, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinking polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.78g:0.9g:65mL, uniformly mixing, reacting for 10 hours at 95 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a 3 wt% calcium chloride solution, stirring and adsorbing for 1.5h, centrifuging, drying the precipitate to obtain a carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into a 3 wt% ammonium carbonate solution, stirring and reacting for 2h, centrifuging, and drying the precipitate to obtain a carboxyl porous polymer loaded with calcium carbonate;

(1.4) dissolving DCC and NHS in DMF, adding a calcium carbonate-loaded carboxyl porous polymer into the DMF, wherein the mass-to-volume ratio of the DCC to the NHS to the calcium carbonate-loaded carboxyl porous polymer to the DMF is 0.09g to 0.05g to 1g, uniformly dispersing, and reacting for 24 hours at 30 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, wherein the mass ratio of the calcium carbonate-loaded carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1:0.05, reacting for 12h at 10 ℃ under stirring, centrifuging, washing the precipitate with ethanol, and drying to obtain the heat stabilizer.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 110 ℃, transferring into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 40 ℃, and transferring into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Example 3

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 90 parts of polyvinyl chloride resin, 25 parts of dioctyl azelate, 15 parts of epoxy fatty acid methyl ester, 4 parts of ammonium octamolybdate, 6 parts of molybdenum trioxide, 8 parts of a heat stabilizer, 30 parts of nano kaolin, 0.1 part of oxidized polyethylene and 0.1 part of an anti-aging agent RD.

The preparation method of the heat stabilizer is characterized in that the heat stabilizer is a porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside, and comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 7.2:1:1.8 into a 1.0 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:50mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.5, reacting for 3 hours at 90 ℃ under stirring, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinked polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.8g:1.1g:70mL, uniformly mixing, reacting for 15h at 85 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into 8 wt% calcium chloride solution, stirring and adsorbing for 1h, centrifuging, drying the precipitate to obtain a carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into 8 wt% ammonium carbonate solution, stirring and reacting for 1h, centrifuging, and drying the precipitate to obtain a carboxyl porous polymer loaded with calcium carbonate;

(1.4) dissolving DCC and NHS in DMF, adding a calcium carbonate-loaded carboxyl porous polymer into the DMF, wherein the mass-volume ratio of the DCC to the NHS to the calcium carbonate-loaded carboxyl porous polymer to the DMF is 0.18g to 0.10g to 1g, uniformly dispersing, and reacting for 20 hours at 20 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, wherein the mass ratio of the calcium carbonate-loaded carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1:0.10, reacting for 10h at 30 ℃ under stirring, centrifuging, washing the precipitate with ethanol, and drying to obtain the heat stabilizer.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 120 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 50 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Comparative example 1

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 20 parts of dioctyl sebacate, 10 parts of epoxy fatty acid methyl ester, 7.5 parts of molybdenum trioxide, 6.5 parts of calcium-zinc heat stabilizer, 25 parts of nano kaolin, 0.08 part of stearic acid and 10100.08 parts of antioxidant.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 115 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 45 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Comparative example 2

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 20 parts of dioctyl sebacate, 10 parts of epoxy fatty acid methyl ester, 7.5 parts of molybdenum trioxide, 6.5 parts of heat stabilizer, 25 parts of nano kaolin, 0.08 part of stearic acid and 10100.08 parts of antioxidant.

The heat stabilizer is a porous polymer internally loaded with calcium carbonate, and the preparation method comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 6.5:1:2.5 into a 0.8 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:45mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.4, reacting for 3.5 hours at 85 ℃ under stirring, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinking polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.6g:0.7g:60mL, uniformly mixing, reacting for 12h at 90 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a 5 wt% calcium chloride solution, stirring and adsorbing for 1.5h, centrifuging, drying the precipitate to obtain the carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into a 5 wt% ammonium carbonate solution, stirring and reacting for 1.5h, centrifuging, and drying the precipitate to obtain the heat stabilizer.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 115 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 45 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Comparative example 3

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 20 parts of dioctyl sebacate, 10 parts of epoxy fatty acid methyl ester, 7.5 parts of molybdenum trioxide, 6.02 parts of porous polymer internally loaded with calcium carbonate, 0.48 part of N- (2-aminophenyl) -N-phenylthiourea, 25 parts of nano kaolin, 0.08 part of stearic acid and 10100.08 parts of antioxidant.

The preparation method of the porous polymer internally loaded with calcium carbonate comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 6.5:1:2.5 into a 0.8 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:45mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.4, reacting for 3.5 hours at 85 ℃ under stirring, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinking polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.6g:0.7g:60mL, uniformly mixing, reacting for 12h at 90 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dispersing the carboxyl porous polymer into a 5 wt% calcium chloride solution, stirring and adsorbing for 1.5h, centrifuging, drying the precipitate to obtain the carboxyl porous polymer loaded with calcium ions, putting the carboxyl porous polymer into a 5 wt% ammonium carbonate solution, stirring and reacting for 1.5h, centrifuging, drying the precipitate to obtain the porous polymer loaded with calcium carbonate inside.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 115 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 45 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

Comparative example 4

An environment-friendly high-strength polyvinyl chloride cable material comprises the following raw materials in parts by weight: 95 parts of polyvinyl chloride resin, 20 parts of dioctyl sebacate, 10 parts of epoxy fatty acid methyl ester, 7.5 parts of molybdenum trioxide, 6.5 parts of heat stabilizer, 25 parts of nano kaolin, 0.08 part of stearic acid and 10100.08 parts of antioxidant.

The heat stabilizer is a porous polymer with thiourea grafted on the surface, and the preparation method comprises the following steps:

(1.1) adding styrene, acrylic acid and divinylbenzene with the mass ratio of 6.5:1:2.5 into a 0.8 wt% SDS aqueous solution, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the volume of an emulsifier aqueous solution is 1g:45mL, uniformly mixing, adding potassium persulfate, wherein the ratio of the total mass of the styrene, the acrylic acid and the divinylbenzene to the mass of the potassium persulfate is 1:0.4, reacting for 3.5 hours at 85 ℃ under stirring, adding ethanol with the volume being three times that of the SDS aqueous solution, centrifuging, washing precipitates with ethanol, and drying to obtain a low-crosslinking polymer;

(1.2) adding a low-crosslinked polymer into 1, 2-dichloroethane, fully dissolving, adding dimethoxymethane and anhydrous ferric chloride, wherein the mass-to-volume ratio of the low-crosslinked polymer to the dimethoxymethane to the anhydrous ferric chloride to the 1, 2-dichloroethane is 1g:0.6g:0.7g:60mL, uniformly mixing, reacting for 12h at 90 ℃ under stirring, centrifuging, washing precipitate with methanol, and drying to obtain a carboxyl porous polymer;

(1.3) dissolving DCC and NHS in DMF, adding a carboxyl porous polymer into the DMF, wherein the mass-volume ratio of the DCC to the NHS to the carboxyl porous polymer to the DMF is 0.013g to 0.08g to 1g, uniformly dispersing the mixture, and reacting the mixture for 22 hours at 25 ℃ under the stirring condition; adding N- (2-aminophenyl) -N-phenylthiourea, wherein the mass ratio of the carboxyl porous polymer to the N- (2-aminophenyl) -N-phenylthiourea is 1:0.08, reacting for 11h at 20 ℃ under stirring, centrifuging, washing the precipitate with ethanol, and drying to obtain the heat stabilizer.

The preparation method of the polyvinyl chloride cable material comprises the following steps: weighing the raw materials according to the parts by weight, adding all the raw materials into a high-speed mixer, mixing at a high speed until the temperature of the materials rises to 115 ℃, transferring the materials into a low-speed mixer, mixing at a low speed until the temperature of the materials drops to 45 ℃, and transferring the materials into a double-screw extruder for extrusion granulation to obtain the environment-friendly high-strength polyvinyl chloride cable material.

The cable materials prepared in examples 1-3 and comparative examples 1-4 were tested for their performance by the following specific methods: testing the tensile strength and the elongation at break of the cable material according to the standard GB/T1040.2-2006; after air heat aging is carried out for 168 hours at the temperature of 100 +/-2 ℃, the tensile strength and the elongation at break of the cable material are tested again; the cable material was tested for HCl emissions on combustion according to standard GB/T17650.1-1998. The results of the performance tests are shown in table 1.

TABLE 1

As can be seen from the data in table 1:

(1) compared with comparative example 1 using a commercially available calcium-zinc heat stabilizer, in example 1, the strength and the thermal stability of the prepared cable material are higher and the emission amount of HCl during combustion is smaller by using the porous polymer with thiourea grafted on the surface and calcium carbonate loaded inside as the heat stabilizer. The calcium-zinc heat stabilizer has poor dispersibility in PVC, and can generate zinc chloride in the action process to catalyze PVC degradation to cause the strength reduction of a cable material, while the heat stabilizer has good compatibility with PVC, hydrogen chloride generated by replacing unstable chlorine atoms with thiourea can be removed in time, and other Lewis acids such as zinc chloride and the like can not be generated, so that the heat stabilization effect is good; in addition, after the heat stabilizer replaces unstable chlorine atoms, covalent crosslinking can be formed among PVC molecular chains, so that the strength of the PVC cable material is further improved. In addition, in the heat stabilizer, the porous polymer can absorb HCl by utilizing the porous structure of the porous polymer, meanwhile, calcium carbonate loaded in the porous polymer can neutralize the absorbed HCl in time, the absorption capacity of the heat stabilizer on hydrogen chloride is improved, HCl desorption is prevented, and the HCl release amount of the polyvinyl chloride cable during combustion can be effectively reduced through the synergistic effect between the porous structure and the calcium carbonate.

(2) Compared with comparative example 2 in which a porous polymer internally loaded with calcium carbonate is used as a heat stabilizer, in example 1, thiourea is grafted on the surface of the heat stabilizer, so that the prepared cable material has higher strength and thermal stability. The thiourea can replace unstable chlorine atoms in a polyvinyl chloride molecular chain, on one hand, the stable chlorine atoms can be blocked from being continuously formed and a large number of conjugated double bonds can be blocked, so that the degradation of PVC is slowed down, on the other hand, the thiourea can be in covalent connection with the PVC molecular chain after replacing the unstable chlorine atoms, and through the mode, the heat stabilizer can form crosslinking among the PVC molecular chains, so that the strength of the PVC cable material is improved.

(3) Compared with comparative example 3 in which the porous polymer internally loaded with calcium carbonate and thiourea are added in a dispersed manner, in example 1, the thiourea is grafted on the surface of the porous polymer, and the prepared cable material has higher strength and thermal stability. The HCl is generated after the thiourea replaces unstable chlorine atoms, the degradation of PVC is accelerated, the long-term thermal stability effect is poor, and the HCl can be removed by the porous polymer by utilizing pores and loaded calcium carbonate, so that the catalytic degradation caused by the contact of the HCl and the PVC is avoided, and the effect of a heat stabilizer is improved; if thiourea and a porous polymer loaded with calcium carbonate inside are added in a dispersing manner, HCl generated after the thiourea replaces unstable chlorine atoms cannot be removed in time.

(4) Compared with comparative example 4 in which the porous polymer with the thiourea grafted on the surface is used as the heat stabilizer, in example 1, calcium carbonate is loaded in the porous polymer, so that the prepared cable material is high in strength and heat stability, and the HCl release amount during combustion is small. The calcium carbonate loaded in the porous polymer can neutralize the adsorbed HCl in time, so that the adsorption capacity of the heat stabilizer to the HCl is improved, HCl desorption is prevented, the degradation of PVC catalyzed by HCl is better avoided, and the HCl release amount of the cable material during combustion is reduced.

Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that the embodiments may be modified or changed without departing from the spirit of the present invention within the scope of the appended claims.