Low-smoke PVC cable material

Abstract

The invention relates to the field of cables, in particular to a low-smoke PVC (polyvinyl chloride) cable material which comprises the following components in parts by weight: 70-90 parts of PVC resin, 22-38 parts of filler, 10-25 parts of a flame retardant, 13-28 parts of a plasticizer, 1.5-5.5 parts of a lubricant and 0.3-1.2 parts of a light stabilizer, wherein the flame retardant is modified magnesium hydroxide. The raw materials used in the low-smoke flame-retardant cable material cooperate with one another to achieve the low-smoke flame-retardant effect, and especially through modification treatment of the flame retardant, the cable material not only keeps excellent flame retardance, but also shows better mechanical strength and aging resistance compared with a traditional cable.

Description

Technical Field

[0001] The invention relates to the field of cables, and in particular to a low-smoke PVC cable material. Background Art

[0002] With the development of economy, the demand for wires and cables is increasing day by day, especially in the fields of high-rise buildings, electronic products, electrical appliances, automobiles, computers and aerospace industry products, the requirements for cable materials are getting higher and higher. Wires and cables are widely used in polyvinyl chloride (PVC) materials, which is the second largest resin variety in the world after polyethylene. PVC cable has the advantages of softness, wear resistance, high mechanical properties, easy processing and high cost performance, and is an ideal power cable material.

[0003] PVC cable material is made of PVC as the main raw material, and various additives such as plasticizers, stabilizers, lubricants, etc. are added. In addition, the flame retardant performance of PVC cable material is poor. When the PVC cable encounters a fire source, the polyvinyl chloride material inside it will decompose rapidly, accompanied by the release of a large amount of smoke and toxic gases. These toxic gases not only pose a threat to human health, but also may accelerate the spread of the fire, bringing great difficulties to the rescue work. Therefore, generally in the PVC cable material formula, tricresyl phosphate is added to partially replace the phthalate plasticizer, and a large amount of inorganic flame retardants, such as magnesium hydroxide (or aluminum hydroxide), are added to prepare low-smoke and low-halogen flame-retardant PVC cable material. Although such an operation improves the flame retardant performance of PVC cable materials to a certain extent and reduces the generation of smoke and harmful gases. However, because a large amount of inorganic flame retardants such as magnesium hydroxide (or aluminum hydroxide) are added, the mechanical properties of PVC cable materials are deteriorated, and many performance indicators are greatly reduced. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a low-smoke PVC cable material.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a low-smoke PVC cable material, which comprises the following components calculated by weight:

[0007] 70-90 parts of PVC resin, 22-38 parts of filler, 10-25 parts of flame retardant, 13-28 parts of plasticizer, 1.5-5.5 parts of lubricant and 0.3-1.2 parts of light stabilizer.

[0008] Preferably, the PVC resin is one of SG-2, SG-3, SG-5, SG-7, and SG-8, or a mixture of multiple thereof, and more preferably Tangshan Sanyou SG-3.

[0009] Preferably, the flame retardant is modified magnesium hydroxide.

[0010] Preferably, the filler is calcium carbonate (CaCO 3 ), including micron calcium carbonate and nano calcium carbonate in a mass ratio of 2-4:1, the particle size of the micron calcium carbonate is 2-3μm, and the particle size of the nano calcium carbonate is 50-100nm.

[0011] Preferably, the plasticizer is a mixture of tricresyl phosphate and dioctyl phthalate, and the mass ratio of tricresyl phosphate to dioctyl phthalate is 1:3-5.

[0012] Preferably, the lubricant is a mixture of one or more of butyl stearate, glyceryl monostearate, zinc stearate, calcium stearate, paraffin, polyethylene wax, and oxidized polyethylene wax. More preferably, it is a mixture of zinc stearate and calcium stearate, and the mass ratio of zinc stearate to calcium stearate is 1-3:1-3.

[0013] Preferably, the light stabilizer is a mixture of one or more of UV-9, UV-531, UV-327, and UV-326, and more preferably UV-327.

[0014] Preferably, the preparation method of modified magnesium hydroxide comprises:

[0015] S1, weighing magnesium hydroxide (MH) powder and adding it to an ethanol aqueous solution, dispersing it evenly at room temperature, then dropping a vinyl silane coupling agent, heating the mixture for reaction, and after the reaction is completed, centrifuging, washing and drying to obtain vinyl magnesium hydroxide;

[0016] S2, weighing ethylene magnesium hydroxide and adding it to toluene, then adding 4-amino-2-mercaptopyrimidine, dispersing evenly at room temperature, introducing nitrogen as a protective gas, stirring and reacting under ultraviolet light for 1-3 hours, and after the reaction is completed, centrifuging, washing and drying to obtain active magnesium hydroxide;

[0017] S3. Weigh adamantanesulfonyl chloride and add it to toluene. After sufficient stirring, add active magnesium hydroxide and disperse it evenly. Under the action of a catalyst and an oxidant, stir and react at 70-110° C. for 8-12 hours. After the reaction is completed, remove the solvent under reduced pressure, wash with alcohol 2-3 times, and dry in vacuo to obtain modified magnesium hydroxide.

[0018] Preferably, in S1, the particle size of the magnesium hydroxide (MH) powder is 10-20 μm, and the mass fraction of the ethanol aqueous solution is 25%-75%.

[0019] Preferably, in S1, the mass volume ratio of magnesium hydroxide (MH) powder and ethanol aqueous solution is 1 g: (10-20) mL.

[0020] Preferably, in S1, the vinyl silane coupling agent is A-172, and the added amount is 3%-12% of the mass of the magnesium hydroxide (MH) powder.

[0021] Preferably, in S2, the mass volume ratio of ethylene magnesium hydroxide, 4-amino-2-mercaptopyrimidine and toluene is 1 g:(0.17-0.34) g:(10-20) mL.

[0022] Preferably, in S2, a photoinitiator is added during the ultraviolet light initiation reaction, and the added amount is 1%-6% of the mass of 4-amino-2-mercaptopyrimidine; wherein the photoinitiator is any one of benzoin dimethyl ether, benzoin diethyl ether, and 2,2-diethoxyacetophenone.

[0023] Preferably, in S3, the mass volume ratio of active magnesium hydroxide, adamantanesulfonyl chloride and toluene is 1 g: (0.24-0.48) g: (15-25) mL.

[0024] Preferably, in S3, the catalyst is tetrabutylammonium iodide, and the added amount is 6%-12% of the mass of adamantanesulfonyl chloride.

[0025] Preferably, in S3, the oxidant is tert-butyl hydroperoxide, and the added amount is 5%-10% of the mass of adamantanesulfonyl chloride.

[0026] In a second aspect, the present invention provides a method for preparing a low-smoke PVC cable material, comprising the following steps:

[0027] Step 1, mixing PVC resin, filler, modified flame retardant and plasticizer at 160-180° C. for 20-30 min to obtain a first mixed raw material;

[0028] Step 2, adding a lubricant, a light stabilizer and a heat stabilizer to the first mixed raw material, and stirring and mixing again under heat preservation for 5-15 minutes to obtain a second mixed raw material;

[0029] Step 3, introducing the second mixed raw material into a twin-screw extruder, and subjecting it to melt extrusion granulation at an extrusion temperature range of 175-200° C., to obtain a low-smoke PVC cable material.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention prepares a PVC cable material, which uses PVC resin as the main material, calcium carbonate of different particle sizes as the filler, tricresyl phosphate as the plasticizer to partially replace the phthalate compound, and the flame retardant is modified magnesium hydroxide. In addition, a lubricant and a light stabilizer are added. The raw materials cooperate with each other to achieve a low-smoke flame retardant effect, especially the modification of the flame retardant, so that the cable material not only maintains excellent flame retardancy, but also exhibits better mechanical strength and aging resistance than traditional cables.

[0032] 2. Flame retardant modified magnesium hydroxide is prepared by modifying the surface of inorganic flame retardant magnesium hydroxide with organic coating. The modification process includes: firstly silanizing magnesium hydroxide to obtain vinyl magnesium hydroxide; then reacting with 4-amino-2-mercaptopyrimidine through vinyl-mercapto click chemistry to obtain active magnesium hydroxide containing thioether group; then combining with adamantane sulfonyl chloride to obtain sulfonamide group through reaction between sulfonyl-amino group, and finally preparing modified magnesium hydroxide.

[0033] 3. Compared with traditional inorganic magnesium hydroxide flame retardants, the modified magnesium hydroxide prepared by the present invention has better compatibility with polyvinyl chloride. After surface modification, the surface of magnesium hydroxide contains a large number of sulfide, sulfonamide, pyrimidine and adamantane groups. It is found through testing that it not only has a certain improvement effect on the flame retardant effect of PVC cables, but also has good performance in mechanical properties and aging resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0035] Figure 1 is a schematic diagram of a scanning electron microscope of a flame retardant prepared in Example 1 of the present invention;

[0036] Figure 2 It is a schematic diagram of a vertical combustion test of the low-smoke PVC cable material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0038] The present invention will be further described below in conjunction with the following examples.

[0039] Example 1

[0040] A low-smoke PVC cable material, calculated by weight, includes the following components:

[0041] 80 parts of PVC resin, 29 parts of filler, 18 parts of flame retardant, 21 parts of plasticizer, 3.5 parts of lubricant and 0.8 parts of light stabilizer.

[0042] The PVC resin model is Tangshan Sanyou SG-3; the filler is calcium carbonate (CaCO 3 ), including micron calcium carbonate and nano calcium carbonate in a mass ratio of 3:1, the particle size of the micron calcium carbonate is 2-3μm, and the particle size of the nano calcium carbonate is 50-100nm; the plasticizer is tricresyl phosphate and dioctyl phthalate in a mass ratio of 1:4; the lubricant is a mixture of zinc stearate and calcium stearate, and the mass ratio of zinc stearate to calcium stearate is 2:1; the light stabilizer is UV-327.

[0043] Wherein, the flame retardant is modified magnesium hydroxide, and the preparation method comprises:

[0044] S1. Weigh magnesium hydroxide powder (MH) with a particle size of 10-20 μm and add it to an aqueous solution of 55% ethanol by mass, and disperse it evenly at room temperature. The mass volume ratio of the magnesium hydroxide powder and the aqueous solution of ethanol is 1 g:15 mL. Then, A-172 is added dropwise in an amount of 8% of the mass of the magnesium hydroxide powder. The temperature is raised to react. After the reaction is completed, centrifuge, wash and dry to obtain ethylene magnesium hydroxide.

[0045] S2, weigh ethylene magnesium hydroxide and add it to toluene, then add 4-amino-2-mercaptopyrimidine, the mass volume ratio of ethylene magnesium hydroxide, 4-amino-2-mercaptopyrimidine and toluene is 1g:0.25g:15mL, disperse evenly at room temperature, introduce nitrogen as protective gas, add 4% of benzoin diethyl ether by mass of 4-amino-2-mercaptopyrimidine, and irradiate at an intensity of 30mw / cm2 , stirring and reacting for 2 hours under the initiation of ultraviolet light with a wavelength of 365 nm, and after the reaction is completed, centrifuging, washing and drying to obtain active magnesium hydroxide;

[0046] S3. Weigh adamantanesulfonyl chloride and add it to toluene. After sufficient stirring, add active magnesium hydroxide. The mass volume ratio of active magnesium hydroxide, adamantanesulfonyl chloride and toluene is 1g:0.36g:20mL. Disperse evenly. Add 10% of the mass of adamantanesulfonyl chloride as catalyst tetrabutylammonium iodide and 7% of the mass of adamantanesulfonyl chloride as oxidant tert-butyl hydroperoxide. Stir and react at 95°C for 10h. After the reaction is completed, remove the solvent under reduced pressure. Wash with alcohol 3 times and dry in vacuo to obtain modified magnesium hydroxide.

[0047] The method for preparing the low-smoke PVC cable material comprises the following steps:

[0048] Step 1, mixing PVC resin, filler, modified flame retardant and plasticizer at 170° C. for 25 minutes to obtain a first mixed raw material;

[0049] Step 2, adding a lubricant, a light stabilizer and a heat stabilizer to the first mixed raw material, and stirring and mixing again under heat preservation for 10 minutes to obtain a second mixed raw material;

[0050] Step 3, introducing the second mixed raw material into a twin-screw extruder, and subjecting it to melt extrusion granulation at an extrusion temperature range of 175-200° C., to obtain a low-smoke PVC cable material.

[0051] Example 2

[0052] A low-smoke PVC cable material, calculated by weight, includes the following components:

[0053] 70 parts of PVC resin, 22 parts of filler, 10 parts of flame retardant, 13 parts of plasticizer, 1.5 parts of lubricant and 0.3 parts of light stabilizer.

[0054] The model of PVC resin is SG-5; the filler is calcium carbonate (CaCO 3 ), including micron calcium carbonate and nano calcium carbonate in a mass ratio of 2:1, the particle size of the micron calcium carbonate is 2-3μm, and the particle size of the nano calcium carbonate is 50-100nm; the plasticizer is a mixture of tricresyl phosphate and dioctyl phthalate, and the mass ratio of tricresyl phosphate to dioctyl phthalate is 1:3; the lubricant is glyceryl monostearate; and the light stabilizer is UV-9.

[0055] Wherein, the flame retardant is modified magnesium hydroxide, and the preparation method comprises:

[0056] S1. Weigh magnesium hydroxide powder (MH) with a particle size of 10-20 μm and add it to an aqueous solution of ethanol with a mass fraction of 25%. Disperse it evenly at room temperature. The mass volume ratio of the magnesium hydroxide powder to the aqueous solution of ethanol is 1 g:10 mL. Then, add A-172 dropwise in an amount of 3% of the mass of the magnesium hydroxide powder. Heat the reaction. After the reaction is completed, centrifuge, wash and dry to obtain ethylene magnesium hydroxide.

[0057] S2, weighing ethylene magnesium hydroxide and adding it to toluene, then adding 4-amino-2-mercaptopyrimidine, the mass volume ratio of ethylene magnesium hydroxide, 4-amino-2-mercaptopyrimidine and toluene is 1g:0.17g:10mL, uniformly dispersed at room temperature, nitrogen gas was introduced as a protective gas, 1% of benzoin dimethyl ether by mass of 4-amino-2-mercaptopyrimidine was added, and the reaction was stirred for 1h under ultraviolet light initiation. After the reaction was completed, the reaction was centrifuged, washed and dried to obtain active magnesium hydroxide;

[0058] S3. Weigh adamantanesulfonyl chloride and add it to toluene. After sufficient stirring, add active magnesium hydroxide. The mass volume ratio of active magnesium hydroxide, adamantanesulfonyl chloride and toluene is 1g:0.24g:15mL. Disperse evenly. Add 6% by mass of adamantanesulfonyl chloride as catalyst tetrabutylammonium iodide and 5% by mass of adamantanesulfonyl chloride as oxidant tert-butyl hydroperoxide. Stir and react at 70°C for 8h. After the reaction is completed, remove the solvent under reduced pressure. Wash twice with alcohol and dry in vacuo to obtain modified magnesium hydroxide.

[0059] The method for preparing the low-smoke PVC cable material comprises the following steps:

[0060] Step 1, mixing PVC resin, filler, modified flame retardant and plasticizer at 180° C. for 20 minutes to obtain a first mixed raw material;

[0061] Step 2, adding a lubricant, a light stabilizer and a heat stabilizer to the first mixed raw material, and stirring and mixing again under heat preservation for 5 minutes to obtain a second mixed raw material;

[0062] Step 3, introducing the second mixed raw material into a twin-screw extruder, and subjecting it to melt extrusion granulation at an extrusion temperature range of 175-200° C., to obtain a low-smoke PVC cable material.

[0063] Example 3

[0064] A low-smoke PVC cable material, calculated by weight, includes the following components:

[0065] 90 parts of PVC resin, 38 parts of filler, 25 parts of flame retardant, 28 parts of plasticizer, 5.5 parts of lubricant and 1.2 parts of light stabilizer.

[0066] The model of PVC resin is SG-7; the filler is calcium carbonate (CaCO 3 ), including micron calcium carbonate and nano calcium carbonate in a mass ratio of 4:1, the particle size of the micron calcium carbonate is 2-3μm, and the particle size of the nano calcium carbonate is 50-100nm; the plasticizer is a mixture of tricresyl phosphate and dioctyl phthalate, and the mass ratio of tricresyl phosphate to dioctyl phthalate is 1:5; the lubricant is oxidized polyethylene wax; and the light stabilizer is UV-326.

[0067] Wherein, the flame retardant is modified magnesium hydroxide, and the preparation method comprises:

[0068] S1. Weigh magnesium hydroxide powder (MH) with a particle size of 10-20 μm and add it to an aqueous solution of 75% ethanol by mass, and disperse it evenly at room temperature. The mass volume ratio of magnesium hydroxide powder to ethanol aqueous solution is 1 g: 20 mL. Then, add A-172 dropwise in an amount of 12% of the mass of magnesium hydroxide powder. Heat the reaction. After the reaction is completed, centrifuge, wash and dry to obtain ethylene magnesium hydroxide.

[0069] S2, weighing ethylene magnesium hydroxide and adding it to toluene, then adding 4-amino-2-mercaptopyrimidine, the mass volume ratio of ethylene magnesium hydroxide, 4-amino-2-mercaptopyrimidine and toluene is 1g:0.34g:20mL, uniformly dispersed at room temperature, nitrogen gas was introduced as a protective gas, 2,2-diethoxyacetophenone with a mass percentage of 6% of 4-amino-2-mercaptopyrimidine was added, stirring and reacting for 3h under ultraviolet light induction, and after the reaction was completed, centrifuged, washed and dried to obtain active magnesium hydroxide;

[0070] S3. Weigh adamantanesulfonyl chloride and add it to toluene. After sufficient stirring, add active magnesium hydroxide. The mass volume ratio of active magnesium hydroxide, adamantanesulfonyl chloride and toluene is 1g:0.48g:25mL. Disperse evenly. Add 12% of the mass of adamantanesulfonyl chloride as catalyst tetrabutylammonium iodide and 10% of the mass of adamantanesulfonyl chloride as oxidant tert-butyl hydroperoxide. Stir and react at 110°C for 12h. After the reaction is completed, remove the solvent under reduced pressure. Wash with alcohol 3 times and dry in vacuo to obtain modified magnesium hydroxide.

[0071] The method for preparing the low-smoke PVC cable material comprises the following steps:

[0072] Step 1, mixing PVC resin, filler, modified flame retardant and plasticizer at 160° C. for 30 minutes to obtain a first mixed raw material;

[0073] Step 2, adding a lubricant, a light stabilizer and a heat stabilizer to the first mixed raw material, and mixing again with stirring under heat preservation for 15 minutes to obtain a second mixed raw material;

[0074] Step 3, introducing the second mixed raw material into a twin-screw extruder, and subjecting it to melt extrusion granulation at an extrusion temperature range of 175-200° C., to obtain a low-smoke PVC cable material.

[0075] Comparative Example 1

[0076] The difference between the PVC cable material prepared in this comparative example and Example 1 is that the flame retardant in the raw material components of the PVC cable material is replaced by ethylene magnesium hydroxide prepared in Example 1, and the other raw material components and weight proportions remain unchanged. The preparation method of the cable material is also the same as that of Example 1.

[0077] Comparative Example 2

[0078] The difference between the PVC cable material prepared in this comparative example and Example 1 is that the flame retardant in the raw material components of the PVC cable material is replaced by the active magnesium hydroxide prepared in Example 1, and the other raw material components and weight proportions remain unchanged. The preparation method of the cable material is also the same as that of Example 1.

[0079] Comparative Example 3

[0080] The difference between the PVC cable material prepared in this comparative example and Example 1 is that the flame retardant in the raw material components of the PVC cable material is replaced by a composite reactant of magnesium hydroxide, adamantanesulfonyl chloride and 4-amino-2-mercaptopyrimidine, and the other raw material components and weight proportions remain unchanged. The preparation method of the cable material is also the same as that of Example 1.

[0081] The preparation method of the flame retardant in this comparative example includes:

[0082] Weigh adamantanesulfonyl chloride and add it to toluene. After fully stirring, add magnesium hydroxide and 4-amino-2-mercaptopyrimidine. The mass volume ratio of magnesium hydroxide, 4-amino-2-mercaptopyrimidine, adamantanesulfonyl chloride and toluene is 1g:0.25g:0.36g:20mL. Disperse evenly. Add 10% of the mass of adamantanesulfonyl chloride as catalyst tetrabutylammonium iodide and 7% of the mass of adamantanesulfonyl chloride as oxidant tert-butyl hydroperoxide. Stir and react at 95°C for 10h. After the reaction is completed, remove the solvent under reduced pressure. Wash with alcohol 3 times and dry in vacuum to obtain a flame retardant.

[0083] Experimental testing

[0084] The PVC cable materials prepared in Example 1 and Comparative Examples 1-3 were respectively tested for performance, including: tensile strength test reference standard GB / T 1040.1-2018, notched impact strength test reference standard GB / T 1843-2008, smoke density test reference standard GB / T 8627-2007, flame retardant grade (UL-94) test reference standard ANSI / UL-94-2009 vertical burning method, aging resistance test is to treat the product at 100 ° C for 120 hours, and then test the change rate of tensile strength.

[0085] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength(MPa) 58.2 46.7 50.4 53.5 <![CDATA[Izod impact strength of cantilever beam (kJ / m 2 )]]> 27.5 20.1 21.7 24.6 Change rate of tensile strength after aging (%) -4.9 -10.4 -8.5 -6.2 Smoke Density Rating (SDR) 42.5 61.6 54.3 50.8 UL-94(3.2mm) V-0 V-1 V-1 V-0

[0086] It can be seen from the test results in the above table that the PVC cable material prepared in Example 1 of the present invention not only has a lower smoke density, but also Figure 2 It can be seen from the two ignitions that it meets the V-0 grade of the UL-94 standard, and also shows better mechanical strength and aging resistance than the control cable.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0088] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A low-smoke PVC cable material, characterized in that: Calculated by weight, it includes the following ingredients: 70-90 parts of PVC resin, 22-38 parts of filler, 10-25 parts of flame retardant, 13-28 parts of plasticizer, 1.5-5.5 parts of lubricant and 0.3-1.2 parts of light stabilizer; Wherein, the flame retardant is modified magnesium hydroxide, and the preparation method of the modified magnesium hydroxide includes: S1, weighing magnesium hydroxide powder and adding it to an ethanol aqueous solution, dispersing it evenly at room temperature, then dropping a vinyl silane coupling agent, heating the mixture for reaction, and after the reaction is completed, centrifuging, washing and drying to obtain vinyl magnesium hydroxide; S2, weighing ethylene magnesium hydroxide and adding it to toluene, then adding 4-amino-2-mercaptopyrimidine, dispersing evenly at room temperature, introducing nitrogen as a protective gas, stirring and reacting under ultraviolet light for 1-3 hours, and after the reaction is completed, centrifuging, washing and drying to obtain active magnesium hydroxide; S3. Weigh adamantanesulfonyl chloride and add it to toluene. After sufficient stirring, add active magnesium hydroxide and disperse it evenly. Under the action of a catalyst and an oxidant, stir and react at 70-110° C. for 8-12 hours. After the reaction is completed, remove the solvent under reduced pressure, wash with alcohol 2-3 times, and dry in vacuo to obtain modified magnesium hydroxide.

2. The low-smoke PVC cable material according to claim 1, characterized in that: The model of the PVC resin is one of SG-2, SG-3, SG-5, SG-7, and SG-8, or a mixture of multiple types.

3. The low-smoke PVC cable material according to claim 1, characterized in that: The filler is calcium carbonate, including micron calcium carbonate and nano calcium carbonate in a mass ratio of 2-4:1, the particle size of the micron calcium carbonate is 2-3 μm, and the particle size of the nano calcium carbonate is 50-100 nm.

4. The low-smoke PVC cable material according to claim 1, characterized in that: The plasticizer is a mixture of tricresyl phosphate and dioctyl phthalate, and the mass ratio of tricresyl phosphate to dioctyl phthalate is 1:3-5.

5. The low-smoke PVC cable material according to claim 1, characterized in that: The lubricant is a mixture of one or more of butyl stearate, glyceryl monostearate, zinc stearate, calcium stearate, paraffin, polyethylene wax, and oxidized polyethylene wax.

6. The low-smoke PVC cable material according to claim 1, characterized in that: The light stabilizer is a mixture of one or more of UV-9, UV-531, UV-327 and UV-326.

7. The low-smoke PVC cable material according to claim 1, characterized in that: In S2, the mass volume ratio of ethylene magnesium hydroxide, 4-amino-2-mercaptopyrimidine and toluene is 1 g: (0.17-0.34) g: (10-20) mL.

8. The low-smoke PVC cable material according to claim 1, characterized in that: In the S3, the mass volume ratio of active magnesium hydroxide, adamantanesulfonyl chloride and toluene is 1 g: (0.24-0.48) g: (15-25) mL.

9. The low-smoke PVC cable material according to claim 1, characterized in that: In the step S3, the catalyst is tetrabutylammonium iodide, and the added amount is 6%-12% of the mass of the adamantanesulfonyl chloride; the oxidant is tert-butyl hydroperoxide, and the added amount is 5%-10% of the mass of the adamantanesulfonyl chloride.

10. A method for preparing the low-smoke PVC cable material according to claim 1, characterized in that: The following steps are involved: Step 1, mixing PVC resin, filler, modified flame retardant and plasticizer at 160-180° C. for 20-30 min to obtain a first mixed raw material; Step 2, adding a lubricant, a light stabilizer and a heat stabilizer to the first mixed raw material, and stirring and mixing again under heat preservation for 5-15 minutes to obtain a second mixed raw material; Step 3, introducing the second mixed raw material into a twin-screw extruder, and subjecting it to melt extrusion granulation at an extrusion temperature range of 175-200° C., to obtain a low-smoke PVC cable material.

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