Migration-resistant cable sheath material and preparation process thereof

Abstract

The present application relates to the field of cable sheaths, and specifically discloses a migration-resistant cable sheath material and a preparation process thereof. The cable sheath material comprises the following raw materials: PVC, filler, stabilizer, PE wax, flame retardant, aluminum hydroxide, a polymer non-migrating polyester plasticizer, and stearic acid; wherein the polymer non-migrating polyester plasticizer comprises diisodecyl phthalate and a mica powder-adipic acid polyester composite plasticizer; its preparation method comprises the following steps: mixing heavy calcium powder with PVC powder, adding stabilizer, PE wax, flame retardant, aluminum hydroxide and stearic acid, stirring, and then adding 1 / 2-2 / 3 of the total amount of the polymer non-migrating polyester plasticizer, stirring, and then adding the remaining non-migrating polymer polyester plasticizer, refining the powder and extruding and granulating to obtain the migration-resistant cable sheath material. The present application has the characteristics of improving the migration resistance of the plasticizer in the cable sheath and improving the durability of the cable sheath.

Description

Technical Field

[0001] The present application relates to the field of cable sheaths, and more specifically, to a migration-resistant cable sheath material and a preparation process thereof. Background Art

[0002] As a key carrier for power transmission and signal transmission, cables are widely used in various fields such as electricity, communications, transportation, and construction. Cable sheath materials, as an important component of cables, play a role in protecting internal conductors and insulation layers, and preventing external environmental factors such as moisture, mechanical damage, and chemicals from causing damage to the cables. The performance of cable sheath materials is directly related to the service life, safety, and reliability of cables.

[0003] Traditional cable sheaths are mostly made of materials such as polyvinyl chloride, polyethylene or thermoplastic elastomers through extrusion molding. Although these materials have certain physical properties and processing convenience, during long-term use, small molecule additives such as plasticizers and stabilizers in the sheath material are prone to migration, resulting in precipitation, hardening or embrittlement on the material surface, which in turn causes the sheath performance to deteriorate, manifested as decreased anti-aging ability and reduced insulation performance, and even affects the overall safety and service life of the cable.

[0004] Therefore, it is of great significance to prepare migration-resistant cable sheath materials for the protection and durability of the cable outer sheath. Summary of the Invention

[0005] In order to improve the migration resistance of plasticizers in cable sheaths and improve the durability of cable sheaths, the present application provides a migration-resistant cable sheath material and a preparation process thereof.

[0006] In a first aspect, the present application provides a migration-resistant cable sheath material, which adopts the following technical solution:

[0007] A migration-resistant cable sheath material comprises the following raw materials in parts by weight:

[0008] 75-95 parts of PVC, 25-40 parts of filler, 6-15 parts of stabilizer, 0.2-0.5 parts of PE wax, 3-7 parts of flame retardant, 12-18 parts of aluminum hydroxide, 55-70 parts of high molecular weight non-migrating polyester plasticizer and 0.1-0.3 parts of stearic acid;

[0009] Among them, the high molecular non-migrating polyester plasticizer includes diisodecyl phthalate and mica powder-adipic acid polyester composite plasticizer in a mass ratio of 1: (3-4). The mica powder-adipic acid polyester composite plasticizer is prepared by immersing and modifying mica powder in a mixed solution of graphene oxide and acrylic acid, and then immersing the mica powder in a mixed monomer solution containing adipic acid, cinnamic acid and polyol, and reacting under the action of an initiator to obtain the mica powder-adipic acid polyester composite plasticizer.

[0010] By adopting the above technical solution, in this application, PVC is used as the base resin as the main component of the cable sheath, fillers are added to improve mechanical properties such as wear resistance, stabilizers are added to prevent PVC from being affected by light, heat and oxidation during processing and use, resulting in performance degradation, and to ensure the stability of the outer sheath, flame retardants improve the flame retardant properties of the cable sheath, aluminum hydroxide not only has a flame retardant effect but also can suppress smoke, further improving the flame retardant properties and safety of the sheath material, PE wax as an external lubricant to reduce melt viscosity, improve extrusion moldability, and reduce the migration of plasticizers during processing, stearic acid as an internal lubricant to promote the plasticization of PVC particles, synergistically with PE wax, and balance processing fluidity and material mechanical properties. While the high molecular non-migrating polyester plasticizer improves the toughness of the sheath, it has excellent migration resistance and maintains the stable performance of the cable sheath.

[0011] The addition of high molecular non-migrating polyester plasticizer is combined with PVC substrate. On the basis of ensuring the flexibility of the material through the entanglement of the plasticizer and the PVC molecular chain, the plasticizer in this application is selected from the compound of diisodecyl phthalate and mica powder-adipic acid polyester composite plasticizer. Diisodecyl phthalate is used as a traditional plasticizer to provide initial plasticization, and it has better low-temperature resistance. The composite plasticizer is modified by immersing mica powder in a mixed solution of graphene oxide and acrylic acid, and then hydroxyl and carboxyl functional groups are introduced on the surface of the mica powder while introducing carbon-carbon unsaturated double bonds. Then, under the action of an initiator, , and react with the mixed monomer to achieve polymerization and esterification on the surface of the mica powder to form a long-chain esterified polyester structure, thereby reducing the migration power of the plasticizer. Secondly, the hydroxyl and other functional groups in the end of the polyester molecule form hydrogen bonds with PVC, fixing it in the PVC matrix and inhibiting its migration. Combined with the lamellar structure of the mica powder, a migration barrier path is formed, which significantly improves its migration resistance. Combined with the polyester layer, a gap is formed between the mica powder and the matrix to form a dense physical barrier, which further reduces the migration rate, thereby improving the migration resistance of the cable sheath and significantly improving the service life of the cable sheath.

[0012] Optionally, the polyol is one or more of ethylene glycol, glycerol and pentaerythritol.

[0013] Optionally, the mica powder-adipic acid polyester composite plasticizer is prepared by the following method:

[0014] 1) Dissolve acrylic acid and graphene oxide in water to prepare a mixed impregnation solution, then add mica powder and ultrasonically impregnate and mix for 20-30 minutes, heat to 80-100°C, stir for 2-3 hours, cool, filter, and dry to obtain pretreated mica powder;

[0015] 2) Adipic acid, cinnamic acid and polyol are mixed and dissolved in water to form a mixed monomer solution, and then the pretreated mica powder prepared in step 1) is added. After stirring for 5-10 minutes, an initiator and a catalyst are added. The temperature is raised to 180-200° C., and the reaction is carried out for 3-4 hours. After cooling, the solution is filtered, washed with alcohol, and then distilled under reduced pressure to obtain a mica powder-adipic acid polyester composite plasticizer.

[0016] By adopting the above technical solution, mica powder is first impregnated and modified with graphene oxide and acrylic acid, and the hydroxyl groups on the surface of the mica powder form chemical bonds with the carboxyl functional groups in the graphene oxide and acrylic acid, thereby further introducing double-bond unsaturated functional groups and functional groups such as hydroxyl groups on the surface of the mica powder. On this basis, the mica powder is then subjected to a monomer solution. Under the action of an initiator and a catalyst, the hydroxyl and carboxyl groups on the surface of the mica powder can be esterified with adipic acid and a polyol. At the same time, cinnamic acid contains carbon-carbon double bonds, carboxyl groups, and benzene ring structures, so that the carbon-carbon double bonds in the cinnamic acid can be polymerized with the carbon-carbon double bonds introduced by the acrylic acid on the surface of the mica powder. The hydroxyl groups in the cinnamic acid can form bonds with the carboxyl groups introduced by the graphene oxide on the surface of the mica powder, thereby preparing a macromolecular chain polyester. In addition, in-situ polyester is achieved on the surface of the mica powder to form a cross-linked network structure.

[0017] A benzene ring rigid group is also introduced, and under the entanglement of mica powder and macromolecular network structure, the migration rate of the plasticizer is significantly reduced. The introduction of the benzene ring rigid group improves its heat stability and effectively inhibits its migration during high temperature or long-term use. Moreover, the formation of functional groups such as hydroxyl groups and polyester in the process can form hydrogen bonds with diisodecanoic acid phthalate, thereby inhibiting its migration. Finally, the specific ratio of plasticizer in this application is resistant to migration, thereby improving the long-term performance of the cable sheath.

[0018] Optionally, when preparing the mica powder-adipic acid polyester composite plasticizer, the mass ratio of mica powder, acrylic acid and graphene oxide added in step 1) is 1: (0.3-0.5): (0.2-0.4), and the amount of the mixed impregnation liquid added is 3-4 times the mass of the mica powder;

[0019] In step 2), the addition mass ratio of adipic acid, cinnamic acid and polyol is 1: (0.3-0.5): (1.2-1.5), and the addition mass ratio of pretreated mica powder to the mixture of adipic acid, cinnamic acid and polyol is 1: (2.5-3.5), the addition amount of initiator is 1-3wt% of the pretreated mica powder, and the addition amount of catalyst is 0.2-0.6wt% of the addition amount of the mixture of adipic acid, cinnamic acid and polyol.

[0020] Optionally, the filler is heavy calcium powder.

[0021] By adopting the above technical solution, heavy calcium powder is used as the main filler, which can significantly and effectively improve the rigidity of the cable sheath and reduce deformation caused by external force extrusion. In addition, the thermal expansion coefficient of heavy calcium powder is lower than that of PVC, which can reduce the deformation of the material when the temperature changes, and ensure the structural stability of the cable in extreme environments.

[0022] Optionally, the filler is a mixture of heavy calcium powder and modified kaolin in a mass ratio of 1:(0.1-0.2), and the modified kaolin is prepared by modifying kaolin with sodium dodecylbenzenesulfonate intercalation and then with aminosilane coupling agent and hydroxyethyl methacrylate.

[0023] By adopting the above technical solution, when a mixture of heavy calcium powder and modified kaolin is selected as the filler, kaolin is mainly used to ensure the improvement effect such as the rigidity of the cable, and the addition of modified kaolin forms a good interface bonding between the mica powder-adipic acid polyester composite plasticizer and the PVC substrate, reducing the enrichment and migration of the plasticizer at the interface and reducing its migration through the gaps between the filler and the PVC matrix.

[0024] Optionally, the modified kaolin is prepared by the following method:

[0025] a. Mix kaolin with a 0.5-1.5 wt% aqueous solution of sodium dodecylbenzenesulfonate, stir at 70-90° C. for 2-3 hours, filter, wash with water, and dry to obtain intercalated kaolin;

[0026] b. Disperse the intercalated kaolin in an ethanol solution, add hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, react at 70-80°C for 1-2 hours, filter and dry after cooling to obtain modified kaolin.

[0027] By adopting the above technical scheme, kaolin is first treated in an aqueous solution of sodium dodecylbenzenesulfonate to achieve sodium dodecylbenzenesulfonate anion group intercalation modification, and benzene ring groups are introduced into the kaolin. Then, the kaolin is modified with a silane coupling agent and hydroxyethyl methacrylate. The silanol groups generated after hydrolysis of the silane coupling agent react with the hydroxyl groups on the surface of the kaolin to introduce amino functional groups. The hydroxyl groups in the hydroxyethyl methacrylate are then chemically bonded with the amino groups to introduce ester functional groups. Finally, the surface of the kaolin contains functional groups such as hydroxyl groups, amino groups and ester groups. The hydroxyl groups and amino groups can form hydrogen bonds with PVC, and the ester groups are more compatible with the ester groups in the plasticizer. Moreover, the benzene rings can also form π bonds with the benzene rings in the plasticizer, thereby enhancing the chemical bonding between the kaolin and the PVC and the plasticizer, and further improving the migration resistance of the cable sheath.

[0028] Finally, in this application, heavy calcium powder and modified kaolin are mixed and used. The heavy calcium powder improves the rigidity of the material and reduces the cost, while the modified kaolin enhances the binding with PVC and plasticizers through its surface active groups and good dispersibility, thereby improving the overall performance of the material. Ultimately, it not only helps to reduce the migration of plasticizers, but also improves the durability and stability of the material.

[0029] Optionally, when preparing the modified kaolin, in step a, the mass concentration of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 0.5-1.5wt%, and the amount of sodium dodecylbenzenesulfonate added is 5-8wt% of the kaolin;

[0030] In step b, the ethanol solution is mixed by ethanol and water in a volume ratio of 1: (0.6-0.8), and the amount of ethanol solution added is 3-5 times the mass of the intercalated kaolin. The mass ratio of the intercalated kaolin, hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane added is 1: (0.1-0.2): (0.5-0.6).

[0031] By adopting the above technical solution and using the above addition amount, the modified kaolin prepared and added to the cable sheath material has better migration resistance.

[0032] Optionally, the stabilizer is a mixture of a calcium-zinc composite heat stabilizer and calcium stearate in a mass ratio of 1:(0.4-0.6).

[0033] In a second aspect, the present application provides a preparation process for a migration-resistant cable sheath material, which adopts the following technical solution:

[0034] A preparation process of a migration-resistant cable sheath material comprises the following steps:

[0035] After mixing heavy calcium powder with PVC powder, add stabilizer, PE wax, flame retardant, aluminum hydroxide and stearic acid, stir, then add 1 / 2-2 / 3 of the total amount of high molecular non-migratory polyester plasticizer, stir and then add the remaining non-migratory high molecular polyester plasticizer, refine the powder and extrude into granules to obtain migration-resistant cable sheath material.

[0036] By adopting the above technical solution, the method provided by this application is simple, convenient and easy to industrialize.

[0037] In summary, this application has the following beneficial effects:

[0038] In this application, the plasticizer is a compound of diisodecyl phthalate and mica powder-adipic acid polyester composite plasticizer. Diisodecyl phthalate is used as a traditional plasticizer to provide initial plasticization, and it has better low-temperature resistance. The composite plasticizer is modified by immersing mica powder in a mixed solution of graphene oxide and acrylic acid, and then introducing hydroxyl and carboxyl functional groups on the surface of the mica powder and introducing carbon-carbon unsaturated double bonds. Then, under the action of an initiator, it reacts with the mixed monomer to achieve polymerization and esterification on the surface of the mica powder to form The long-chain esterified polyester structure reduces the migration power of the plasticizer. Secondly, the functional groups such as hydroxyl groups at the end of the polyester molecule form hydrogen bonds with PVC, fixing it in the PVC matrix and inhibiting its migration. Combined with the lamellar structure of the mica powder, a migration barrier is formed, which significantly improves its migration resistance. The polyester layer forms a gap filling between the mica powder and the matrix to form a dense physical barrier, further reducing the migration rate, thereby improving the migration resistance of the cable sheath and significantly improving the service life of the cable sheath. DETAILED DESCRIPTION

[0039] The present application is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0040] In the following examples, PVC S-1300 (i.e., PVC powder with a degree of polymerization of 1300) was used as PVC powder; stearic acid was stearic acid 1801; a phosphorus-nitrogen flame retardant was used as the flame retardant, specifically Clariant's halogen-free flame retardant Exolit AP 462 (high-efficiency phosphorus-nitrogen AP-462) manufactured by Dongguan Weijie New Materials Co., Ltd.; and a calcium-zinc composite heat stabilizer manufactured by Shandong Yueyang New Materials Co., Ltd. was used as the calcium-zinc composite heat stabilizer.

[0041] The following preparation example is a preparation example of mica powder-adipic acid polyester composite plasticizer

[0042] Preparation Example 1

[0043] A method for preparing a mica powder-adipic acid polyester composite plasticizer comprises the following steps:

[0044] 1) Dissolve acrylic acid and graphene oxide in water to prepare a mixed impregnation solution, then add mica powder and ultrasonically impregnate and mix for 25 minutes, then heat to 90°C, stir for 2.5 hours, cool, filter, and dry to obtain pretreated mica powder;

[0045] The mass ratio of mica powder, acrylic acid and graphene oxide is 1:0.4:0.3, and the amount of mixed impregnation liquid added is 3.5 times the mass of mica powder.

[0046] 2) Adipic acid, cinnamic acid and polyol are mixed in a mass ratio of 1:0.4:1.3 to prepare a mixed monomer, and the polyol is pentaerythritol. The mixed monomer is then dissolved in 2.5 times the mass of water to form a mixed monomer solution;

[0047] Then, the pretreated mica powder prepared in step 1) was added to the mixed monomer solution, with the added mass ratio of the pretreated mica powder to the mixed monomer being 1:3. After stirring for 8 minutes, the initiator benzoyl peroxide and the catalyst tetrabutyl titanate were added, with the initiator added in an amount of 2wt% of the pretreated mica powder and the tetrabutyl titanate added in an amount of 0.5wt% of the monomer mixture. The temperature was raised to 190°C, the reaction was carried out for 3.5 hours, the solution was cooled, filtered, washed with alcohol, and then distilled under reduced pressure (residual solvent was removed at 180°C under a vacuum condition of -0.1 MPa) to obtain a mica powder-adipic acid polyester composite plasticizer.

[0048] Preparation Example 2

[0049] A method for preparing a mica powder-adipic acid polyester composite plasticizer comprises the following steps:

[0050] 1) Dissolve acrylic acid and graphene oxide in water to prepare a mixed impregnation solution, then add mica powder and ultrasonically impregnate and mix for 20 minutes, heat to 80°C, stir for 3 hours, cool, filter, and dry to obtain pretreated mica powder;

[0051] The mass ratio of mica powder, acrylic acid and graphene oxide is 1:0.3:0.2, and the amount of mixed impregnation liquid added is 3 times the mass of mica powder;

[0052] 2) Adipic acid, cinnamic acid and polyol are mixed in a mass ratio of 1:0.3:1.2 to prepare a mixed monomer, and propylene glycol is selected as the polyol. The mixed monomer is then dissolved in 2 times the mass of water to form a mixed monomer solution;

[0053] Then, the pretreated mica powder prepared in step 1) was added to the mixed monomer solution, with the added mass ratio of the pretreated mica powder to the mixed monomer being 1:2.5. After stirring for 5 minutes, the initiator benzoyl peroxide and the catalyst tetrabutyl titanate were added, with the initiator added in an amount of 1wt% of the pretreated mica powder and the tetrabutyl titanate added in an amount of 0.2wt% of the monomer mixture. The solution was heated to 180°C, reacted for 4 hours, cooled, filtered, washed with alcohol, and then distilled under reduced pressure (removing residual solvent at 180°C under a vacuum condition of -0.1 MPa) to obtain a mica powder-adipic acid polyester composite plasticizer.

[0054] Preparation Example 3

[0055] A method for preparing a mica powder-adipic acid polyester composite plasticizer comprises the following steps:

[0056] 1) Dissolve acrylic acid and graphene oxide in water to prepare a mixed impregnation solution, then add mica powder and ultrasonically impregnate and mix for 30 minutes, heat to 100°C, stir for 2 hours, cool, filter, and dry to obtain pretreated mica powder;

[0057] The mass ratio of mica powder, acrylic acid and graphene oxide is 1:0.5:0.4, and the amount of mixed impregnation liquid added is 3-4 times the mass of mica powder;

[0058] 2) Adipic acid, cinnamic acid and polyol are mixed in a mass ratio of 1:0.5:1.5 to prepare a mixed monomer, and the polyol is pentaerythritol. The mixed monomer is then dissolved in 3 times the mass of water to form a mixed monomer solution;

[0059] Then, the pretreated mica powder prepared in step 1) was added to the mixed monomer solution, with the added mass ratio of the pretreated mica powder to the mixed monomer being 1:3.5. After stirring for 10 minutes, the initiator benzoyl peroxide and the catalyst tetrabutyl titanate were added, with the initiator added in an amount of 3wt% of the pretreated mica powder and the tetrabutyl titanate added in an amount of 0.6wt% of the monomer mixture. The temperature was raised to 200°C, reacted for 3 hours, cooled, filtered, washed with alcohol, and then distilled under reduced pressure (residual solvent was removed at 180°C under a vacuum condition of -0.1 MPa) to obtain a mica powder-adipic acid polyester composite plasticizer.

[0060] Comparative Preparation Example 1

[0061] A method for preparing a mica powder-adipic acid polyester composite plasticizer is carried out according to the method in Preparation Example 1, except that acrylic acid is not added in step 1).

[0062] Comparative Preparation Example 2

[0063] A method for preparing a mica powder-adipic acid polyester composite plasticizer is carried out according to the method in Preparation Example 1, except that cinnamic acid is not added in step 2).

[0064] Comparative Preparation Example 3

[0065] A method for preparing a mica powder-adipic acid polyester composite plasticizer is carried out according to the method in Preparation Example 1, except that the treatment in step 1) is not performed, and the pretreated mica powder in step 2) is replaced with an equal amount of mica powder.

[0066] The following preparation example is a preparation example of modified kaolin

[0067] Preparation Example 4

[0068] A method for preparing modified kaolin comprises the following steps:

[0069] a. Mix kaolin with a 1 wt% aqueous solution of sodium dodecylbenzenesulfonate, stir at 80°C for 2.5 hours, filter, wash with water, and dry to obtain intercalated kaolin. The amount of sodium dodecylbenzenesulfonate added is 6 wt% of the kaolin.

[0070] b. Disperse the intercalated kaolin in 4 times the mass of an ethanol solution (a mixture of ethanol and water in a volume ratio of 1:0.7), add hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, and react at 75°C for 1.5 hours. After cooling, filter and dry to obtain modified kaolin. The added mass ratio of the intercalated kaolin, hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.1:0.5.

[0071] Preparation Example 5

[0072] A method for preparing modified kaolin comprises the following steps:

[0073] a. Mix kaolin with a 0.5 wt% aqueous solution of sodium dodecylbenzenesulfonate, stir at 70°C for 3 h, filter, wash with water, and dry to obtain intercalated kaolin. The amount of sodium dodecylbenzenesulfonate added is 5 wt% of the kaolin.

[0074] b. Disperse the intercalated kaolin in 3 times the mass of an ethanol solution (a mixture of ethanol and water in a volume ratio of 1:0.6), add hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, and react at 70°C for 2 hours. After cooling, filter and dry to obtain modified kaolin. The added mass ratio of the intercalated kaolin, hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.1:0.5.

[0075] Preparation Example 6

[0076] A method for preparing modified kaolin comprises the following steps:

[0077] a. Mix kaolin with a 1.5 wt% aqueous solution of sodium dodecylbenzenesulfonate, stir at 90°C for 2 h, filter, wash with water, and dry to obtain intercalated kaolin. The amount of sodium dodecylbenzenesulfonate added is 8 wt% of the kaolin.

[0078] b. Disperse the intercalated kaolin in 5 times by mass of an ethanol solution (a mixture of ethanol and water in a volume ratio of 1:0.8), add hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, and react at 80°C for 1 hour. After cooling, filter and dry to obtain modified kaolin. The added mass ratio of the intercalated kaolin, hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.2:0.6.

[0079] Preparation Example 7

[0080] A method for preparing modified kaolin is carried out according to the method in Preparation Example 4, except that an equal amount of sodium dodecylbenzenesulfonate is replaced by sodium dodecyl sulfate in step a.

[0081] Preparation Example 8

[0082] A method for preparing modified kaolin is carried out according to the method in Preparation Example 4, except that hydroxyethyl methacrylate is not added in step b.

[0083] Example 1

[0084] A preparation process of a migration-resistant cable sheath material comprises the following steps:

[0085] First, add 31.5kg of filler, then add 87.5kg of PVC powder, and then add 10.5kg of stabilizer, 0.28kg of PE wax, 4.9kg of flame retardant, 15.4kg of aluminum hydroxide and 0.14kg of stearic acid. After stirring at a low speed of 300r / min for 20min, add 40.2kg of high molecular non-migrating polyester plasticizer and stir at a high speed of 1200r / min and heat to 90°C. After stirring for 10min, add 21.4kg of high molecular non-migrating polyester plasticizer and refine the powder to 155°C. After refining the powder, discharge the material to a twin-screw extruder for extrusion granulation to obtain a migration-resistant cable sheath material. The screw temperature is: zone 1 temperature 125°C, zone 2 temperature 130°C, zone 3 temperature 135°C, zone 4 temperature 138°C, zone 5 temperature 142°C, zone 6 temperature 145°C, and die head temperature 148°C.

[0086] Among them, the filler is heavy calcium powder, the stabilizer is a mixture of calcium zinc composite heat stabilizer and calcium stearate in a mass ratio of 1:0.5, the flame retardant is a phosphorus nitrogen flame retardant, and the high molecular non-migrating polyester plasticizer includes diisodecyl phthalate in a mass ratio of 1:3.5 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 1.

[0087] Example 2

[0088] A preparation process of a migration-resistant cable sheath material comprises the following steps:

[0089] First, add 25kg of filler, then add 75kg of PVC powder, and then add 6kg of stabilizer, 0.2kg of PE wax, 3kg of flame retardant, 12kg of aluminum hydroxide and 0.1kg of stearic acid. After stirring at a low speed of 300r / min for 20min, add 27kg of high molecular non-migrating polyester plasticizer and stir at a high speed of 1200r / min and heat to 90℃. After stirring for 10min, add 28kg of high molecular non-migrating polyester plasticizer and refine the powder to 155℃. After refining, discharge the material to a twin-screw extruder for extrusion granulation to obtain migration-resistant cable sheath material. The screw temperature is: zone 1 temperature 125℃, zone 2 temperature 130℃, zone 3 temperature 135℃, zone 4 temperature 138℃, zone 5 temperature 142℃, zone 6 temperature 145℃, and die head temperature 148℃.

[0090] Among them, the filler is heavy calcium powder, the stabilizer is a mixture of calcium zinc composite heat stabilizer and calcium stearate in a mass ratio of 1:0.4, the flame retardant is a phosphorus nitrogen type flame retardant, and the high molecular non-migrating polyester plasticizer includes diisodecyl phthalate in a mass ratio of 1:3 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 2.

[0091] Example 3

[0092] A preparation process of a migration-resistant cable sheath material comprises the following steps:

[0093] First, add 40kg of filler, then add 95kg of PVC powder, and then add 15kg of stabilizer, 0.5kg of PE wax, 7kg of flame retardant, 18kg of aluminum hydroxide and 0.3kg of stearic acid. After stirring at a low speed of 300r / min for 20min, add 47kg of high molecular non-migrating polyester plasticizer and stir at a high speed of 1200r / min and heat to 90℃. After stirring for 10min, add 23kg of high molecular non-migrating polyester plasticizer and refine the powder to 155℃. After refining, discharge the material to a twin-screw extruder for extrusion granulation to obtain migration-resistant cable sheath material. The screw temperature is: zone 1 temperature 125℃, zone 2 temperature 130℃, zone 3 temperature 135℃, zone 4 temperature 138℃, zone 5 temperature 142℃, zone 6 temperature 145℃, and die head temperature 148℃.

[0094] Among them, the filler is heavy calcium powder, the stabilizer is a mixture of calcium zinc composite heat stabilizer and calcium stearate in a mass ratio of 1:0.6, the flame retardant is a phosphorus nitrogen type flame retardant, and the high molecular non-migrating polyester plasticizer includes diisodecyl phthalate in a mass ratio of 1:4 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 3.

[0095] Example 4

[0096] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 1, except that a mixture of heavy calcium powder and modified kaolin prepared in Preparation Example 4 with a mass ratio of 1:0.15 is used as the filler.

[0097] Example 5

[0098] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 4, except that a mixture of heavy calcium powder and modified kaolin prepared in Preparation Example 5 with a mass ratio of 1:0.1 is used as the filler.

[0099] Example 6

[0100] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 4, except that a mixture of heavy calcium powder and modified kaolin prepared in Preparation Example 6 with a mass ratio of 1:0.2 is used as the filler.

[0101] Examples 7-8

[0102] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 4, except that the modified kaolin is the modified kaolin prepared in Preparation Example 7 and Preparation Example 8, respectively.

[0103] Example 9

[0104] A preparation process of a migration-resistant cable sheath material is carried out according to the method in Example 4, except that an equal amount of modified kaolin is replaced by kaolin.

[0105] Comparative Examples 1-3

[0106] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 1, except that the mica powder-adipic acid polyester composite plasticizer is selected from the mica powder-adipic acid polyester composite plasticizer prepared in Comparative Preparation Examples 1-3.

[0107] Comparative Example 4

[0108] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Example 1, except that an equal amount of a mica powder-adipic acid polyester composite plasticizer is replaced with a polyester plasticizer, and the polyester plasticizer is an adipic acid polyester plasticizer. The preparation process is specifically carried out by the following method:

[0109] Adipic acid and pentaerythritol were mixed in a mass ratio of 1:1.3 to obtain a monomer mixture, which was dissolved in 1 mass multiple of N,N-dimethylformamide. Tetrabutyl titanate was added, and the temperature was raised to 140°C. After reacting for 1 hour, the temperature was further raised to 190°C, and the reaction was continued for 2 hours. The mixture was cooled and then distilled under reduced pressure (residual solvent was removed at 180°C under a vacuum condition of -0.1 MPa), to obtain a polyester plasticizer, wherein the amount of tetrabutyl titanate added was 0.5 wt% of the amount of the monomer mixture added.

[0110] Comparative Example 5

[0111] A preparation process for a migration-resistant cable sheath material is carried out according to the method in Comparative Example 4, except that an equal amount of mica powder-adipic acid polyester composite plasticizer is replaced by a mixture of mica powder and a polyester plasticizer, the polyester plasticizer is the polyester plasticizer prepared in Comparative Example 4, and the added mass ratio of mica powder to polyester plasticizer is 1:3.

[0112] Performance testing

[0113] The cable sheath materials prepared in the examples and comparative examples of the present application were tested for migration resistance according to the method in HG / T 4454-2012 "Determination of Migration of Plasticizers in Plastics". PS and ABS boards were used as absorbent sheets, respectively. The test temperature was 60°C and the test time was 72 hours. The mass change of the absorbent sheet was obtained by the test. The plasticizer migration rate (%) = the mass change of the absorbent sheet (g) / the amount of plasticizer added (g). The test results of the PS migration resistance and the ABS migration resistance were respectively measured, and the results are shown in Table 1 below.

[0114] In addition, the tensile strength retention rate and elongation at break retention rate of the cable sheath material after the above migration test were measured, and the test results are shown in Table 1 below.

[0115] Table 1:

[0116]

[0117] During the use of cable sheath materials, the migration of plasticizers can cause precipitation, hardening or catalysis on the material surface, thereby affecting the overall performance and service life of the cable. The migration resistance of the cable sheath material can be intuitively evaluated by the plasticizer migration rate. The high retention rates of tensile strength and elongation at break indicate that the cable sheath material can maintain high mechanical properties and flexibility after the migration test. Combined with the test results in Table 1 above, it can be seen that the cable sheath material prepared in the embodiment of the present application has excellent resistance to PS migration and ABS migration, as well as excellent tensile strength retention and elongation at break retention, and has a better service life.

[0118] Combining the test results of Example 1 with Examples 4-6, it can be seen that when heavy calcium powder and modified kaolin are used as fillers, it helps to further improve the migration resistance of the cable sheath, and its mechanical property retention ability is further improved. Combined with the test results of Example 7 and Example 8, when sodium dodecyl sulfate is used as the intercalation modifier when preparing the modified kaolin in Example 7, compared with the use of sodium dodecylbenzene sulfonate in Example 4, its migration resistance and mechanical property retention ability are both reduced. In Example 8, when hydroxyethyl methacrylate is not added during the post-treatment of the kaolin intercalation modification, its migration resistance is also reduced. The introduction of ester groups improves the bonding between the plasticizer and filler and the PVC matrix, further improving the migration resistance. Combined with the test results of Example 9, when kaolin is directly used as a filler, its migration resistance is significantly reduced.

[0119] Combined with the test results of Example 1 and Comparative Example 1, when preparing the mica powder-adipic acid polyester composite plasticizer, when acrylic acid is not added during the pretreatment of the mica powder, it affects the subsequent in-situ polymerization to form polyester, and the final migration resistance is significantly reduced. When cinnamic acid is not added in Comparative Example 2, the migration resistance is also significantly reduced. The carboxyl and benzene ring groups have an anchoring effect on the prepared polyester plasticizer with a macromolecular branched structure, which significantly improves its migration resistance. When the mica powder in Comparative Example 3 is not pretreated and modified and directly reacts with the monomer solution, its migration resistance is significantly reduced. Combined with the test results of Comparative Example 4, when ordinary adipic acid plasticizers are used as plasticizers, the migration resistance is reduced compared to the in-situ generation of polyester chains using mica powder in Example 1. The lamellar structure of mica powder can increase the migration path, thereby improving the migration resistance, and its physical anchoring effect further improves the migration resistance. Combined with the test results of Comparative Example 5, when mica powder and polyester plasticizer are simply mixed and added, the two lack a binding effect. Moreover, due to the dispersibility of mica powder and the increase in the gap between mica powder and PVC matrix, the migration resistance is actually reduced. The use of the plasticizer in this application helps to improve its migration resistance.

[0120] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A migration-resistant cable sheath material, characterized in that: The invention comprises the following raw materials in parts by weight: 75-95 parts of PVC, 25-40 parts of filler, 6-15 parts of stabilizer, 0.2-0.5 parts of PE wax, 3-7 parts of flame retardant, 12-18 parts of aluminum hydroxide, 55-70 parts of high molecular weight non-migrating polyester plasticizer and 0.1-0.3 parts of stearic acid; wherein the high molecular weight non-migrating polyester plasticizer comprises diisodecyl phthalate and mica powder-adipic acid polyester composite plasticizer in a mass ratio of 1:(3-4); the mica powder-adipic acid polyester composite plasticizer is prepared by immersing mica powder in a mixed solution of graphene oxide and acrylic acid for modification, and then immersing the mica powder in a mixed monomer solution containing adipic acid, cinnamic acid and polyol, and reacting under the action of an initiator to obtain the mica powder-adipic acid polyester composite plasticizer; The flame retardant is a phosphorus-nitrogen type flame retardant, and the filler is heavy calcium powder or a mixture of heavy calcium powder and modified kaolin.

2. The migration-resistant cable sheath material according to claim 1, characterized in that: The polyol is selected from one or more of ethylene glycol, glycerol and pentaerythritol.

3. The migration-resistant cable sheath material according to claim 1, characterized in that: The mica powder-adipic acid polyester composite plasticizer is prepared by the following method: 1) dissolving acrylic acid and graphene oxide in water to prepare a mixed impregnation liquid, then adding mica powder and ultrasonically impregnating and mixing for 20-30 minutes, heating to 80-100°C, stirring for 2-3 hours, cooling, filtering, and drying to obtain pretreated mica powder; 2) mixing adipic acid, cinnamic acid and polyol and dissolving them in water to form a mixed monomer solution, then adding the pretreated mica powder prepared in step 1), stirring for 5-10 minutes, adding initiator and catalyst, heating to 180-200°C, reacting for 3-4 hours, filtering after cooling, washing with alcohol, and then distilling under reduced pressure to obtain the mica powder-adipic acid polyester composite plasticizer.

4. The migration-resistant cable sheath material according to claim 3, characterized in that: When preparing the mica powder-adipic acid polyester composite plasticizer, the addition mass ratio of mica powder, acrylic acid and graphene oxide in step 1) is 1: (0.3-0.5): (0.2-0.4), and the addition amount of the mixed impregnation liquid is 3-4 times the mass of the mica powder; in step 2), the addition mass ratio of adipic acid, cinnamic acid and polyol is 1: (0.3-0.5): (1.2-1.5), and the addition mass ratio of pretreated mica powder and the mixture of adipic acid, cinnamic acid and polyol is 1: (2.5-3.5), the addition amount of the initiator is 1-3wt% of the pretreated mica powder, and the addition amount of the catalyst is 0.2-0.6wt% of the addition amount of the adipic acid, cinnamic acid and polyol mixture.

5. The migration-resistant cable sheath material according to claim 1, characterized in that: The filler is a mixture of heavy calcium powder and modified kaolin in a mass ratio of 1: (0.1-0.2). The modified kaolin is prepared by modifying kaolin with sodium dodecylbenzenesulfonate intercalation and then with aminosilane coupling agent and hydroxyethyl methacrylate.

6. The migration-resistant cable sheath material according to claim 5, characterized in that: The modified kaolin is prepared by the following method: a. Mixing kaolin with an aqueous solution of sodium dodecylbenzenesulfonate, stirring at 70-90°C for 2-3 hours, filtering, washing with water, and drying to obtain intercalated kaolin; b. Dispersing the intercalated kaolin in an ethanol solution, adding hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, reacting at 70-80°C for 1-2 hours, cooling, filtering, and drying to obtain modified kaolin.

7. The migration-resistant cable sheath material according to claim 6, characterized in that: When preparing the modified kaolin, in step a, the mass concentration of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 0.5-1.5wt%, and the amount of sodium dodecylbenzenesulfonate added is 5-8wt% of the kaolin; in step b, the ethanol solution is mixed by ethanol and water in a volume ratio of 1:(0.6-0.8), and the amount of ethanol solution added is 3-5 times the mass of the intercalated kaolin, and the mass ratio of the intercalated kaolin, hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane added is 1:(0.1-0.2):(0.5-0.6).

8. The migration-resistant cable sheath material according to claim 1, characterized in that: The stabilizer is a mixture of a calcium zinc composite heat stabilizer and calcium stearate in a mass ratio of 1: (0.4-0.6).

9. A process for preparing the migration-resistant cable sheath material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing the filler with PVC powder, adding a stabilizer, PE wax, flame retardant, aluminum hydroxide and stearic acid, stirring, then adding 1 / 2-2 / 3 of the total amount of a high molecular non-migratory polyester plasticizer, stirring, and then adding the remaining non-migratory high molecular polyester plasticizer, refining the powder and then extruding and granulating to obtain a migration-resistant cable sheath material.

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