Migration-resistant cable sheath material and preparation process thereof

Abstract

The invention relates to the field of cable sheaths, and particularly discloses a migration-resistant cable sheath material and a preparation process thereof, and the cable sheath material comprises the following raw materials: PVC, a filler, a stabilizer, PE wax, a flame retardant, aluminum hydroxide, a polymer non-migration polyester plasticizer and stearic acid; wherein the macromolecular non-migration polyester plasticizer comprises di-iso-decylphthalate and a mica powder-adipic acid polyester composite plasticizer; the preparation method comprises the following steps: mixing the heavy calcium carbonate powder and the PVC powder, adding the stabilizer, the PE wax, the flame retardant, the aluminum hydroxide and the stearic acid, stirring, adding 1 / 2-2 / 3 of the total addition amount of the high-molecular non-migration polyester plasticizer, stirring, adding the rest of the non-migration high-molecular polyester plasticizer, refining the powder, extruding and granulating to obtain the migration-resistant cable sheath material. The cable sheath has the characteristics that the migration resistance of the plasticizer in the cable sheath is improved, and the durability of the cable sheath is improved.

Description

Technical Field

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

[0002] As a key carrier for power transmission and signal transmission, cables are widely used in various fields such as electricity, communication, transportation, and construction. As an important component of cables, cable sheath materials play a role in protecting the internal conductors and insulating layers, preventing losses to the cables caused by external environments such as moisture, mechanical damage, and chemical substances. Their performance directly affects the service life, safety, and reliability of the cables.

[0003] Traditional cable sheaths are mostly prepared by extrusion molding processes using materials such as polyvinyl chloride, polyethylene, or thermoplastic elastomers. 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 materials are prone to migration phenomena, resulting in surface precipitation, hardening, or embrittlement of the materials, and then leading to deterioration of the sheath performance, manifested as a decline in anti-aging ability and insulation performance, and even affecting the overall safety and service life of the cables.

[0004] Therefore, preparing a cable sheath material resistant to migration is of great significance 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 the cable sheath and enhance the durability of the cable sheath, the present application provides a cable sheath material for resistance to migration and its preparation process.

[0006] In the first aspect, the present application provides a cable sheath material for resistance to migration, adopting the following technical solution: A cable sheath material for resistance to migration, comprising 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 part of PE wax, 3 - 7 parts of flame retardant, 12 - 18 parts of aluminum hydroxide, 55 - 70 parts of high molecular non-migrating polyester plasticizer, and 0.1 - 0.3 part of stearic acid; Among them, the high molecular non-migrating polyester plasticizer comprises diisodecyl phthalate and mica powder - adipic acid polyester composite plasticizer with a mass ratio of 1:(3 - 4). The mica powder - adipic acid polyester composite plasticizer is prepared by impregnating mica powder in a mixed solution of graphene oxide and acrylic acid, then soaking it 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.

[0007] By adopting the above technical scheme, 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 reduced performance, ensuring 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 reduces melt viscosity, improves extrusion molding, and reduces the migration of plasticizers during processing, stearic acid as an internal lubricant, promotes the plasticization of PVC particles, and synergizes with PE wax to 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.

[0008] 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, and carbon-carbon unsaturated double bonds are introduced. Then, under the action of an initiator, , reacting with the mixed monomer to achieve polymerization and esterification on the surface of 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 at the end of the polyester molecule form hydrogen bonds with PVC, fixing it in the PVC matrix to inhibit its migration. Combined with the lamellar structure of the mica powder, a barrier path for migration 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.

[0009] Optionally, the polyol is one or more of ethylene glycol, propylene glycol and pentaerythritol.

[0010] Optionally, the mica powder-adipic acid polyester composite plasticizer is prepared by the following method: 1) Dissolve acrylic acid and graphene oxide in water to obtain 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; 2), Mix adipic acid, cinnamic acid and polyol and dissolve them in water to form a mixed monomer solution. Then add the pretreated mica powder prepared in step 1), stir for 5 - 10 min, add initiator and catalyst, heat up to 180 - 200 °C, react for 3 - 4 h, cool, filter, wash with alcohol, and then obtain mica powder - adipic acid polyester composite plasticizer by vacuum distillation.

[0011] By adopting the above technical solution, the mica powder is first impregnated and modified with graphene oxide and acrylic acid. The hydroxyl groups on the surface of the mica powder form chemical bonding with the carboxyl functional groups in graphene oxide and acrylic acid, thereby further introducing double - bond unsaturated functional groups and hydroxyl groups and other functional groups on its surface. On this basis, it acts in the monomer solution. Under the action of initiator and catalyst, the hydroxyl groups and carboxyl groups on the surface of the mica powder can esterify with adipic acid and 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 cinnamic acid can polymerize with the carbon - carbon double bonds introduced by acrylic acid on the surface of the mica powder, and its hydroxyl groups can form bonding with the carboxyl groups and others introduced by graphene oxide on the surface of the mica powder, obtaining macromolecular chain polyester, and realizing in - situ polyester on the surface of the mica powder to form a cross - linked network structure; The benzene ring rigid group is also introduced. Under the entanglement of the mica powder and the macromolecular network structure, the migration rate of the plasticizer is significantly reduced. Coupled with the introduction of the benzene ring rigid group, its heat resistance stability is improved, effectively inhibiting its migration during high - temperature or long - term use. Moreover, during this process, the formation of functional groups such as hydroxyl groups and polyester can form hydrogen - bonding interactions with bis(2 - ethylhexyl) phthalate, inhibiting its migration. Finally, the plasticizer with a specific ratio in this application has good migration resistance and improves the long - term use performance of the cable sheath.

[0012] 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 addition amount of the mixed impregnating solution is 3 - 4 times the mass of the mica powder; In step 2), the mass ratio of adipic acid, cinnamic acid and polyol added is 1:(0.3 - 0.5):(1.2 - 1.5), and the mass ratio of the pretreated mica powder to the mixture of adipic acid, cinnamic acid and polyol is 1:(2.5 - 3.5). The addition amount of the initiator is 1 - 3 wt% of the pretreated mica powder, and the addition amount of the catalyst is 0.2 - 0.6 wt% of the addition amount of the mixture of adipic acid, cinnamic acid and polyol.

[0013] Optionally, the filler is selected as heavy calcium powder.

[0014] By adopting the above technical solution, using heavy calcium powder as the main filler can significantly and effectively improve the rigidity of the cable sheath, reduce the deformation caused by external force extrusion. Moreover, 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.

[0015] Optionally, the filler is a mixture of heavy calcium powder and modified kaolin with a mass ratio of 1:(0.1 - 0.2). The modified kaolin is prepared by intercalating kaolin with sodium dodecylbenzenesulfonate and then modifying it with an amino silane coupling agent and 2-hydroxyethyl methacrylate.

[0016] By adopting the above technical solution, when the filler is a mixture of heavy calcium powder and modified kaolin, kaolin is the main component to ensure the improvement effect such as the rigidity of the cable, while the addition of modified kaolin forms a good interfacial bond between 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 voids between the filler and the PVC matrix.

[0017] Optionally, the modified kaolin is prepared by the following method: a. Mix kaolin with an aqueous solution of 0.5 - 1.5 wt% sodium dodecylbenzenesulfonate, stir at 70 - 90 °C for 2 - 3 h, then filter, wash with water, and dry to obtain intercalated kaolin. b. Disperse the intercalated kaolin in an ethanol solution, add 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, react at 70 - 80 °C for 1 - 2 h, cool, filter, and dry to obtain modified kaolin.

[0018] By adopting the above technical solution, when kaolin is first treated in an aqueous solution of sodium dodecylbenzenesulfonate, the intercalation modification of the anionic group of sodium dodecylbenzenesulfonate is realized, and benzene ring groups are introduced onto the kaolin. Then, after modification with a silane coupling agent and 2-hydroxyethyl methacrylate, the hydrolyzed silane coupling agent generates silanol groups that react with the surface hydroxyl groups of kaolin to introduce amino functional groups. Then, the hydroxyl groups in 2-hydroxyethyl methacrylate form chemical bonds with the amino groups to introduce ester functional groups. Finally, the surface of kaolin contains functional groups such as hydroxyl, amino, and ester groups. Its hydroxyl and amino groups can form hydrogen bond interactions with PVC, while the ester groups have higher compatibility with the ester groups in the plasticizer, and its benzene rings can also form π-bond interactions with the benzene rings in the plasticizer, ultimately enhancing the chemical binding force between kaolin, PVC, and the plasticizer and further improving the migration resistance of the cable sheath.

[0019] Finally, in the present application, the combined use of ground calcium carbonate and modified kaolin results in ground calcium carbonate enhancing the rigidity of the material and reducing costs, while the modified kaolin, through its surface active groups and good dispersibility, enhances the binding with PVC and plasticizers, improving the overall properties of the material. Ultimately, this not only helps to reduce the migration of plasticizers but also improves the durability and stability of the material.

[0020] 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 - 1.5 wt%, and the addition amount of sodium dodecylbenzenesulfonate is 5 - 8 wt% of the kaolin. In step b, the ethanol solution is a mixture of ethanol and water in a volume ratio of 1:(0.6 - 0.8), and the addition amount of the ethanol solution is 3 - 5 mass times that of the intercalated kaolin. The added mass ratio of the intercalated kaolin, 2 - hydroxyethyl methacrylate, and γ - aminopropyltriethoxysilane is 1:(0.1 - 0.2):(0.5 - 0.6).

[0021] By adopting the above - mentioned technical solution, the modified kaolin prepared with the above - mentioned addition amounts has better migration resistance when added to the cable sheath material.

[0022] Optionally, the stabilizer is a mixture of a calcium - zinc composite heat stabilizer and calcium stearate with a mass ratio of 1:(0.4 - 0.6).

[0023] In a second aspect, the present application provides a preparation process for a cable sheath material with migration resistance, adopting the following technical solution: A preparation process for a cable sheath material with migration resistance includes the following steps: Mix ground calcium carbonate and PVC powder, then add a stabilizer, PE wax, a flame retardant, aluminum hydroxide, and stearic acid, and stir. Then add 1 / 2 - 2 / 3 of the total addition amount of the non - migrating polyester plasticizer, stir, and then add the remaining non - migrating polyester plasticizer. After powder refining, extrude and pelletize to obtain the cable sheath material with migration resistance.

[0024] By adopting the above - mentioned technical solution, the method provided by the present application is simple and convenient, and is easy to industrialize.

[0025] In summary, the present application has the following beneficial effects: In this application, the plasticizer is selected as a compound of diisodecyl phthalate and mica powder - adipic acid polyester composite plasticizer. Diisodecyl phthalate, as a traditional plasticizer, provides initial plasticization and has better low-temperature resistance. The composite plasticizer is obtained by impregnating mica powder in a mixed solution of graphene oxide and acrylic acid. Hydroxyl and carboxyl functional groups are introduced onto the surface of mica powder, and at the same time, carbon-carbon unsaturated double bonds are introduced. Then, under the action of an initiator, it reacts with the mixed monomers to achieve polymerization and esterification on the surface of mica powder, forming a long-chain esterified polyester structure, thereby reducing the migration driving force of the plasticizer. Secondly, hydrogen bond interactions are formed between functional groups such as hydroxyl groups at the ends of polyester molecules and PVC, fixing it in the PVC matrix and inhibiting its migration. Combining with the lamellar structure of mica powder to form an obstacle path for migration significantly improves its migration resistance. Then, the polyester layer forms a gap filling between 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 Embodiments

[0026] The following further elaborates on this application in conjunction with embodiments. It should be specifically noted that: for those not specifying specific conditions in the following embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. All raw materials used in the following embodiments can be obtained from ordinary commercial sources unless otherwise specified.

[0027] In the following embodiments, the PVC powder is selected as the PVC S - 1300 model (i.e., PVC powder with a polymerization degree of 1300); stearic acid is selected as stearic acid 1801; the flame retardant is selected as a phosphorus-nitrogen type flame retardant, specifically the halogen-free flame retardant Exolit AP 462, a high-efficiency phosphorus-nitrogen series AP - 462 from Clariant of Dongguan Weijie New Materials Co., Ltd.; the calcium-zinc composite heat stabilizer is selected as the calcium-zinc stabilizer from Shandong Yueyang New Materials Co., Ltd.

[0028] The following preparation examples are for the preparation of mica powder - adipic acid polyester composite plasticizer Preparation Example 1 A preparation method of mica powder - adipic acid polyester composite plasticizer includes the following steps: 1). Dissolve acrylic acid and graphene oxide in water to obtain a mixed impregnating solution. Then add mica powder and ultrasonically impregnate and mix for 25 min, then heat to 90 °C, stir for 2.5 h and then cool, filter, and dry to obtain pretreated mica powder; Among them, the added mass ratio of mica powder, acrylic acid, and graphene oxide is 1:0.4:0.3, and the addition amount of the mixed impregnating solution is 3.5 mass times that of mica powder; 2), Mix adipic acid, cinnamic acid and polyol according to the added mass ratio of 1:0.4:1.3 to obtain a mixed monomer. The polyol is selected as pentaerythritol. Then dissolve the mixed monomer in 2.5 times the mass of water to form a mixed monomer solution; Then add the pretreated mica powder prepared in step 1) to the mixed monomer solution. The added mass ratio of the pretreated mica powder to the mixed monomer is 1:3. After stirring for 8 min, add benzoyl peroxide as the initiator and tetrabutyl titanate as the catalyst. The addition amount of the initiator is 2 wt% of the pretreated mica powder, and the addition amount of tetrabutyl titanate is 0.5 wt% of the addition amount of the monomer mixture. Heat up to 190 °C and react for 3.5 h. After cooling, filter and wash with alcohol, and then perform vacuum distillation (remove the residual solvent at 180 °C under the vacuum condition of -0.1 MPa) to obtain the mica powder - adipic acid polyester composite plasticizer.

[0029] Preparation Example 2 A preparation method of a mica powder - adipic acid polyester composite plasticizer includes the following steps: 1), Dissolve acrylic acid and graphene oxide in water to obtain a mixed impregnating solution. Then add mica powder and ultrasonically impregnate and mix for 20 min. Then heat up to 80 °C, stir for 3 h, cool, filter, and dry to obtain pretreated mica powder; Among them, the added mass ratio of mica powder, acrylic acid and graphene oxide is 1:0.3:0.2, and the addition amount of the mixed impregnating solution is 3 times the mass of mica powder; 2), Mix adipic acid, cinnamic acid and polyol according to the added mass ratio of 1:0.3:1.2 to obtain a mixed monomer. The polyol is selected as glycerol. Then dissolve the mixed monomer in 2 times the mass of water to form a mixed monomer solution; Then add the pretreated mica powder prepared in step 1) to the mixed monomer solution. The added mass ratio of the pretreated mica powder to the mixed monomer is 1:2.5. After stirring for 5 min, add benzoyl peroxide as the initiator and tetrabutyl titanate as the catalyst. The addition amount of the initiator is 1 wt% of the pretreated mica powder, and the addition amount of tetrabutyl titanate is 0.2 wt% of the addition amount of the monomer mixture. Heat up to 180 °C and react for 4 h. After cooling, filter and wash with alcohol, and then perform vacuum distillation (remove the residual solvent at 180 °C under the vacuum condition of -0.1 MPa) to obtain the mica powder - adipic acid polyester composite plasticizer.

[0030] Preparation Example 3 A preparation method of a mica powder - adipic acid polyester composite plasticizer includes the following steps: 1), Dissolve acrylic acid and graphene oxide in water to obtain a mixed impregnating solution. Then add mica powder and ultrasonically impregnate and mix for 30 min. Then heat up to 100 °C, stir for 2 h, cool, filter, and dry to obtain pretreated mica powder; Among them, the mass ratio of mica powder, acrylic acid and graphene oxide added is 1:0.5:0.4, and the addition amount of the mixed impregnating solution is 3 to 4 times the mass of mica powder; 2), Mix adipic acid, cinnamic acid and polyol according to the added mass ratio of 1:0.5:1.5 to obtain a mixed monomer. Pentaerythritol is selected as the polyol. Then dissolve the mixed monomer in 3 times the mass of water to form a mixed monomer solution; Then add the pretreated mica powder prepared in step 1) to the mixed monomer solution. The added mass ratio of the pretreated mica powder to the mixed monomer is 1:3.5. After stirring for 10 min, add initiator benzoyl peroxide and catalyst tetrabutyl titanate. The addition amount of the initiator is 3 wt% of the pretreated mica powder, and the addition amount of tetrabutyl titanate is 0.6 wt% of the addition amount of the monomer mixture. Heat up to 200 °C and react for 3 h. After cooling, filter, wash with alcohol, and then carry out vacuum distillation (remove the residual solvent at 180 °C under the vacuum condition of -0.1 MPa) to obtain mica powder - adipic acid polyester composite plasticizer.

[0031] Comparative Preparation Example 1 A preparation method of 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).

[0032] Comparative Preparation Example 2 A preparation method of 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).

[0033] Comparative Preparation Example 3 A preparation method of 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 carried out, and the pretreated mica powder in step 2) is replaced with mica powder in equal amount.

[0034] The following preparation examples are preparation examples of modified kaolin Preparation Example 4 A preparation method of modified kaolin includes the following steps: a. Mix kaolin with an aqueous solution of sodium dodecylbenzenesulfonate with a mass concentration of 1 wt%, stir at 80 °C for 2.5 h, then filter, wash with water, and dry to obtain intercalated kaolin. The addition amount of sodium dodecylbenzenesulfonate is 6 wt% of kaolin; b. Disperse the intercalated kaolin in an ethanol solution with a mass multiple of 4 (mixed by ethanol and water in a volume ratio of 1:0.7). After adding 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, react at 75 °C for 1.5 h. After cooling, filter and dry to obtain the modified kaolin. The added mass ratio of the intercalated kaolin, 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.1:0.5.

[0035] Preparation Example 5 A preparation method of modified kaolin, comprising the following steps: a. Mix kaolin with an aqueous solution of sodium dodecylbenzenesulfonate with a mass concentration of 0.5 wt%. After stirring at 70 °C for 3 h, filter, wash with water, and dry to obtain the intercalated kaolin. The added amount of sodium dodecylbenzenesulfonate is 5 wt% of the kaolin; b. Disperse the intercalated kaolin in an ethanol solution with a mass multiple of 3 (mixed by ethanol and water in a volume ratio of 1:0.6). After adding 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, react at 70 °C for 2 h. After cooling, filter and dry to obtain the modified kaolin. The added mass ratio of the intercalated kaolin, 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.1:0.5.

[0036] Preparation Example 6 A preparation method of modified kaolin, comprising the following steps: a. Mix kaolin with an aqueous solution of sodium dodecylbenzenesulfonate with a mass concentration of 1.5 wt%. After stirring at 90 °C for 2 h, filter, wash with water, and dry to obtain the intercalated kaolin. The added amount of sodium dodecylbenzenesulfonate is 8 wt% of the kaolin; b. Disperse the intercalated kaolin in an ethanol solution with a mass multiple of 5 (mixed by ethanol and water in a volume ratio of 1:0.8). After adding 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane, react at 80 °C for 1 h. After cooling, filter and dry to obtain the modified kaolin. The added mass ratio of the intercalated kaolin, 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:0.2:0.6.

[0037] Preparation Example 7 A preparation method of modified kaolin is carried out according to the method in Preparation Example 4, except that in step a, sodium dodecylbenzenesulfonate is equally replaced with sodium dodecyl sulfate.

[0038] Preparation Example 8 A preparation method of modified kaolin is carried out according to the method in Preparation Example 4, except that 2-hydroxyethyl methacrylate is not added in step b.

[0039] Example 1

[0040] A preparation process of a cable sheath material for resistance to migration, comprising the following steps: First, put 31.5 kg of filler, then add 87.5 kg of PVC powder, then add 10.5 kg of stabilizer, 0.28 kg of PE wax, 4.9 kg of flame retardant, 15.4 kg of aluminum hydroxide and 0.14 kg of stearic acid. After low-speed stirring at a speed of 300 r / min for 20 min, add 40.2 kg of high-molecular non-migrating polyester plasticizer and then stir at a high speed of 1200 r / min and heat up to 90 °C. After stirring for 10 min, add 21.4 kg of high-molecular non-migrating polyester plasticizer, mill the powder to 155 °C, discharge the milled powder to a twin-screw extruder for extrusion granulation to obtain the cable sheath material for resistance to migration. The screw temperatures are: the temperature of the first zone is 125 °C, the temperature of the second zone is 130 °C, the temperature of the third zone is 135 °C, the temperature of the fourth zone is 138 °C, the temperature of the fifth zone is 142 °C, the temperature of the sixth zone is 145 °C, and the temperature of the die head is 148 °C.

[0041] Among them, the filler is selected as heavy calcium powder, the stabilizer is selected as a mixture of calcium-zinc composite heat stabilizer and calcium stearate with a mass ratio of 1:0.5, the flame retardant is selected as a phosphorus-nitrogen type flame retardant, and the high-molecular non-migrating polyester plasticizer includes diisodecyl phthalate with a mass ratio of 1:3.5 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 1.

[0042] Example 2

[0043] A preparation process of a cable sheath material for resistance to migration, comprising the following steps: First, put 25 kg of filler, then add 75 kg of PVC powder, then add 6 kg of stabilizer, 0.2 kg of PE wax, 3 kg of flame retardant, 12 kg of aluminum hydroxide and 0.1 kg of stearic acid. After low-speed stirring at a speed of 300 r / min for 20 min, add 27 kg of high-molecular non-migrating polyester plasticizer and then stir at a high speed of 1200 r / min and heat up to 90 °C. After stirring for 10 min, add 28 kg of high-molecular non-migrating polyester plasticizer, mill the powder to 155 °C, discharge the milled powder to a twin-screw extruder for extrusion granulation to obtain the cable sheath material for resistance to migration. The screw temperatures are: the temperature of the first zone is 125 °C, the temperature of the second zone is 130 °C, the temperature of the third zone is 135 °C, the temperature of the fourth zone is 138 °C, the temperature of the fifth zone is 142 °C, the temperature of the sixth zone is 145 °C, and the temperature of the die head is 148 °C.

[0044] Among them, the filler is selected as heavy calcium powder, the stabilizer is selected as a mixture of calcium-zinc composite heat stabilizer and calcium stearate with a mass ratio of 1:0.4, the flame retardant is selected as a phosphorus-nitrogen type flame retardant, and the high-molecular non-migrating polyester plasticizer includes diisodecyl phthalate with a mass ratio of 1:3 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 2.

[0045] Example 3

[0046] A preparation process of a cable sheath material for resistance to migration, comprising the following steps: First, put in 40 kg of filler, then add 95 kg of PVC powder, and then add 15 kg of stabilizer, 0.5 kg of PE wax, 7 kg of flame retardant, 18 kg of aluminum hydroxide, and 0.3 kg of stearic acid. After low-speed stirring at a speed of 300 r / min for 20 min, add 47 kg of a high-molecular non-migrating polyester plasticizer, and then stir at a high speed of 1200 r / min and heat up to 90 °C. After stirring for 10 min, add 23 kg of the high-molecular non-migrating polyester plasticizer, knead the powder to 155 °C, discharge the kneaded powder to a twin-screw extruder for extrusion granulation to obtain the cable sheath material for resistance to migration. The screw temperatures are: the temperature of the first zone is 125 °C, the temperature of the second zone is 130 °C, the temperature of the third zone is 135 °C, the temperature of the fourth zone is 138 °C, the temperature of the fifth zone is 142 °C, the temperature of the sixth zone is 145 °C, and the die head temperature is 148 °C.

[0047] Among them, the filler is selected as heavy calcium powder, the stabilizer is selected as a mixture of a calcium-zinc composite heat stabilizer and calcium stearate with a mass ratio of 1:0.6, the flame retardant is selected as a phosphorus-nitrogen type flame retardant, and the high-molecular non-migrating polyester plasticizer includes diisodecyl phthalate with a mass ratio of 1:4 and the mica powder-adipic acid polyester composite plasticizer prepared in Preparation Example 3.

[0048] Example 4

[0049] A preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 1, the difference being that the filler is selected as a mixture of heavy calcium powder with a mass ratio of 1:0.15 and the modified kaolin prepared in Preparation Example 4.

[0050] Example 5

[0051] A preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 4, the difference being that the filler is selected as a mixture of heavy calcium powder with a mass ratio of 1:0.1 and the modified kaolin prepared in Preparation Example 5.

[0052] Example 6

[0053] A preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 4, the difference being that the filler is selected as a mixture of heavy calcium powder with a mass ratio of 1:0.2 and the modified kaolin prepared in Preparation Example 6.

[0054] Examples 7 - 8 A preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 4, the difference being that the modified kaolin is respectively selected as the modified kaolin prepared in Preparation Example 7 and Preparation Example 8.

[0055] Example 9

[0056] The preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 4, except that the modified kaolin is replaced with kaolin in equal amounts.

[0057] Comparative Examples 1-3 The preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 1, except that the mica powder - adipic acid polyester composite plasticizer is respectively selected from the mica powder - adipic acid polyester composite plasticizers prepared in Comparative Preparation Examples 1-3.

[0058] Comparative Example 4 The preparation process of a cable sheath material for resistance to migration is carried out according to the method in Example 1, except that the mica powder - adipic acid polyester composite plasticizer is replaced with a polyester plasticizer in equal amounts. The polyester plasticizer is selected as an adipic acid polyester plasticizer, and is specifically prepared by the following method: Adipic acid and pentaerythritol are mixed in a mass ratio of 1:1.3 to obtain a monomer mixture. The monomer mixture is dissolved in 1 mass multiple of N,N-dimethylformamide, tetrabutyl titanate is added, and then the temperature is raised to 140 °C. After reacting for 1 h, the temperature is further raised to 190 °C and the reaction is continued for 2 h, followed by cooling. Then, it is subjected to vacuum distillation (removing the residual solvent at 180 °C under a vacuum condition of -0.1 MPa) to obtain the polyester plasticizer, wherein the addition amount of tetrabutyl titanate is 0.5 wt% of the addition amount of the monomer mixture.

[0059] Comparative Example 5 The preparation process of a cable sheath material for resistance to migration is carried out according to the method in Comparative Example 4, except that the mica powder - adipic acid polyester composite plasticizer is replaced with a mixture of mica powder and a polyester plasticizer in equal amounts. The polyester plasticizer is selected as the polyester plasticizer prepared in Comparative Example 4, and the addition mass ratio of mica powder to the polyester plasticizer is 1:3.

[0060] Performance testing The cable sheath materials prepared in the examples and comparative examples of this application are subjected to a migration resistance performance test according to the method in HG / T 4454-2012 "Determination of Plasticizer Migration in Plastics". PS plates and ABS plates are used as absorption sheets respectively. The test temperature is 60 °C and the test time is 72 h. The mass change of the absorption sheets is measured, and the plasticizer migration rate (%) = mass change of the absorption sheet (g) / addition amount of the plasticizer (g). The test results of the PS migration resistance rate and the ABS migration resistance rate are measured respectively, and the results are shown in Table 1 below.

[0061] In addition, the tensile strength retention rate and the elongation at break retention rate of the cable sheath material after the above migration test are measured, and the test results are shown in Table 1 below.

[0062] Table 1:

[0063] During the use of cable sheath materials, the migration of plasticizers can lead to surface precipitation, hardening or catalysis of the materials, thereby affecting the overall performance and service life of the cables. By the plasticizer migration rate, the migration resistance of cable sheath materials can be visually evaluated. High retention rates of tensile strength and elongation at break indicate that the cable sheath materials can maintain high mechanical properties and flexibility after the migration test. Combining the test results in Table 1 above, it can be seen that the cable sheath materials prepared in the embodiments of the present application have excellent resistance to PS migration and ABS migration, and at the same time have excellent retention rates of tensile strength and elongation at break, and have a better service life.

[0064] Combining the test results of Example 1 and Examples 4-6, it can be seen that when heavy calcium powder and modified kaolin are selected as fillers, it helps to further improve the migration resistance of the cable sheath, and its ability to maintain mechanical properties is further improved. Combining the test results of Example 7 and Example 8, when sodium dodecyl sulfate is used as an intercalation modifier during the preparation of modified kaolin in Example 7, compared with sodium dodecylbenzenesulfonate used in Example 4, its migration resistance and ability to maintain mechanical properties are both reduced. When 2-hydroxyethyl methacrylate is not added during the post-treatment of the intercalated modification of kaolin in Example 8, its migration resistance is also reduced. The introduction of ester groups is better for the combination between plasticizers and fillers and the PVC matrix, further improving the migration resistance; Combining the test results of Example 9, when kaolin is directly used as a filler, its migration resistance is significantly reduced.

[0065] Combined with the test results of Example 1 and Comparative Example 1, when preparing mica powder - adipic acid polyester composite plasticizer, when acrylic acid was not added during the pretreatment of mica powder, its influence on the subsequent in-situ polymerization to form polyester, and ultimately the migration resistance performance was significantly reduced. When cinnamic acid was not added in Comparative Example 2, the migration resistance performance was also significantly reduced. The carboxyl and benzene ring groups had an anchoring effect on the polyester plasticizer with a macromolecular branched chain structure, significantly improving its migration resistance performance. When mica powder in Comparative Example 3 directly reacted with the monomer solution without pretreatment modification, its migration resistance performance was significantly reduced. Combined with the test results of Comparative Example 4, when a common adipic acid plasticizer was selected as the plasticizer, compared with in-situ generating polyester chains with mica powder in Example 1, its migration resistance was reduced. The lamellar structure of mica powder could increase the migration path, thereby improving the migration resistance performance, and further improving the migration resistance performance with its physical anchoring effect. Combined with the test results of Comparative Example 5, when mica powder and polyester plasticizer were simply mixed and added, there was a lack of binding effect between them, and due to the dispersibility of mica powder and the increase in the gap between mica powder and the PVC matrix, its migration resistance performance was reduced instead. Using the plasticizer in this application helps to improve its migration resistance performance.

[0066] This specific embodiment is only an explanation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A cable sheath material for resistance to migration, characterized in that, It includes 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 part of PE wax, 3 - 7 parts of flame retardant, 12 - 18 parts of aluminum hydroxide, 55 - 70 parts of high - molecular non - migrating polyester plasticizer, and 0.1 - 0.3 part of stearic acid; Among them, the high - molecular non - migrating polyester plasticizer includes diisodecyl phthalate and mica - adipic acid polyester composite plasticizer with a mass ratio of 1:(3 - 4). The mica - adipic acid polyester composite plasticizer is prepared by impregnating mica powder in a mixed solution of graphene oxide and acrylic acid, then soaking it in a mixed monomer solution containing adipic acid, cinnamic acid, and polyol, and reacting under the action of an initiator to obtain the mica - adipic acid polyester composite plasticizer.

2. The cable sheath material for migration resistance according to claim 1, wherein: The polyol is selected from one or more of ethylene glycol, glycerol, and pentaerythritol.

3. The cable sheath material for resistance to migration according to claim 1, characterized in that: The mica - adipic acid polyester composite plasticizer is prepared by the following method: 1). Dissolve acrylic acid and graphene oxide in water to obtain a mixed impregnating solution, then add mica powder and ultrasonically impregnate and mix for 20 - 30 min, then heat up to 80 - 100 °C, stir for 2 - 3 h, cool, filter, and dry to obtain pretreated mica powder; 2). Mix adipic acid, cinnamic acid, and polyol and dissolve them in water to form a mixed monomer solution, then add the pretreated mica powder prepared in step 1), stir for 5 - 10 min, then add an initiator and a catalyst, heat up to 180 - 200 °C, react for 3 - 4 h, cool, filter, wash with alcohol, and then obtain the mica - adipic acid polyester composite plasticizer by vacuum distillation.

4. The cable sheath material for migration resistance according to claim 3, characterized in that: When preparing the mica - 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 addition amount of the mixed impregnating solution is 3 - 4 times the mass of mica powder; In step 2), the mass ratio of adipic acid, cinnamic acid, and polyol added is 1:(0.3 - 0.5):(1.2 - 1.5), and the mass ratio of the pretreated mica powder to the mixture of adipic acid, cinnamic acid, and polyol is 1:(2.5 - 3.5). The addition amount of the initiator is 1 - 3 wt% of the pretreated mica powder, and the addition amount of the catalyst is 0.2 - 0.6 wt% of the addition amount of the mixture of adipic acid, cinnamic acid, and polyol.

5. The cable sheath material for migration resistance according to claim 1, characterized in that: The filler is selected as heavy calcium powder.

6. The cable sheath material for resistance to migration according to claim 1, characterized in that: The filler is selected as a mixture of heavy calcium powder and modified kaolin with a mass ratio of 1:(0.1 - 0.2). The modified kaolin is prepared by intercalating kaolin with sodium dodecylbenzenesulfonate and then modifying it with amino silane coupling agent and 2 - hydroxyethyl methacrylate.

7. The cable sheath material for migration resistance according to claim 6, characterized in that: The modified kaolin is prepared by the following method: a. Mix kaolin with an aqueous solution of sodium dodecylbenzenesulfonate, stir at 70 - 90 °C for 2 - 3 h, then filter, wash with water, and dry to obtain intercalated kaolin; b. Disperse the intercalated kaolin in an ethanol solution, add 2 - hydroxyethyl methacrylate and γ - aminopropyltriethoxysilane, react at 70 - 80 °C for 1 - 2 h, cool, filter, and dry to obtain modified kaolin.

8. The cable sheath material for resistance to migration according to claim 7, 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 0.5-1.5 wt%, and the addition amount of sodium dodecylbenzenesulfonate is 5-8 wt% of the kaolin; In step b, the ethanol solution is prepared by mixing ethanol and water in a volume ratio of 1:(0.6-0.8), and the addition amount of the ethanol solution is 3-5 mass times that of the intercalated kaolin. The addition mass ratio of the intercalated kaolin, 2-hydroxyethyl methacrylate and γ-aminopropyltriethoxysilane is 1:(0.1-0.2):(0.5-0.6).

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

10. A preparation process for a cable sheath material for migration resistance as described in any one of claims 1-9, characterized in that: It includes the following steps: Mix the heavy calcium powder and PVC powder, then add the stabilizer, PE wax, flame retardant, aluminum hydroxide and stearic acid, stir, then add 1 / 2-2 / 3 of the total addition amount of the high molecular non-migrating polyester plasticizer, stir and then add the remaining non-migrating high molecular polyester plasticizer, and extrude and pelletize after powder refining to obtain the cable sheath material for anti-migration.

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