SEBS / PET light flame-retardant insulating coiled material as well as preparation method and application thereof

Abstract

The invention discloses an SEBS / PET light flame-retardant insulating coiled material as well as a preparation method and application thereof. The coiled material comprises the following components in parts by weight: 40-60 parts of a hydrogenated styrene-butadiene block copolymer, 5-15 parts of polyethylene glycol terephthalate, 5-10 parts of a plasticizer, 5-10 parts of a flame retardant, 5-10 parts of a stabilizer, 5-10 parts of an antioxidant, 3-5 parts of a dispersing agent and 1-3 parts of an adhesive. The composite material can be directly prepared into a solid coiled material, and can realize uniform and tight coating of a wire based on the thermal shrinkage of the composite material while meeting the performances of voltage resistance, adhesive force, elasticity, weather resistance, dielectric loss and the like, so that the composite material can meet the outdoor construction conditions of wider humidity and temperature ranges; in practical application, the coiled material with the thickness of 2 mm can meet the one-way ground insulation requirement of a 110 KV high-voltage cable (breakdown voltage gt; 63.5 kV); the coiled material is low in density, small in bare conductor insulation construction load capacity and convenient for coating operation of overhead bare conductors, and has a remarkable application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating materials, and particularly to a SEBS / PET lightweight flame-retardant insulating coil and its preparation method and application. Background Art

[0002] With the rapid economic development and the increasing improvement of people's living standards, the demand for electricity has also increased significantly, and higher requirements have been put forward for the distribution network. With the rapid development of the distribution network, its scale is expanding day by day, and its importance is increasing day by day. As an important part of the distribution network, overhead lines are complex in structure, widely distributed, old in line, and poor in operating conditions, posing great potential safety hazards. Overhead lines mainly refer to overhead open wires, which are erected above the ground. They are transmission lines that use insulators to fix transmission wires on poles standing upright on the ground to transmit electric energy. They are relatively convenient for erection and maintenance, and have a lower cost, but are easily affected by meteorological conditions and cause failures. At the same time, the entire transmission corridor occupies a large amount of land area and is likely to cause electromagnetic interference to the surrounding environment. Conductors are components used to conduct current and transmit electric energy. They are often tested by various natural conditions during operation and must have characteristics such as good electrical conductivity, light weight, high mechanical strength, low price, and corrosion resistance. Since the resources of aluminum in China are richer than those of copper, and the price difference between silver and copper is relatively large, almost all steel-cored aluminum stranded wires are used. However, exposed overhead lines are prone to accidents in densely populated areas, among trees, and during fishing, causing personal and property losses and injuries.

[0003] The insulation treatment of the injection insulation layer robot can effectively solve the problem of partial insulation of distribution lines, accelerate the insulation transformation of the distribution network without being restricted by power outages and the environment, reduce the intensity of manual operations and the transformation cost, and effectively solve the problems of distribution network transformation and power outages in some areas. From the perspective of the safe and reliable operation of the power grid, in some special sections such as fish ponds, near buildings, forest areas, and cross-overs, the exposed overhead lines are insulated to ensure power supply and personal safety; from the perspective of economic savings, the lines can be locally insulated and transformed, and there is no need for whole-line insulation transformation. This not only shortens the transformation time of the distribution network, achieves the goal of energy conservation and environmental protection, but also reduces the intensity of manual operations and the transformation cost, and effectively solves the problems of distribution network transformation and power outages in some areas.

[0004] However, the existing insulating material coating devices have relatively high requirements for the performance of the coating. For example, it is required that the coating has a certain fluidity so that efficient coating can be achieved under a small extrusion thrust, and it can dry quickly under normal outdoor conditions without dripping, sagging, etc. At the same time, it is required that the coating has excellent insulation after drying; it is required that the coating has flame retardancy, less auxiliary materials added, low density, and at the same time, indicators such as adhesion, elasticity, weather resistance, and dielectric loss meet the requirements of national standards such as "Overhead Insulated Cables with Rated Voltage of 10 kV" (GB / T 14049-2008). In order to meet the above requirements simultaneously, researchers have carried out extensive development of new coatings. For example, a coating for improving the performance of overhead conductors is disclosed in the patent application No. 201210587245.X. In order to be smoothly coated on the surface of ordinary ACSR conductors, the content of organic solvents in the raw materials of the coating is 30-39 wt%, and the content of curing agent is 12-16 wt%; the transmission line coating described in the patent application No. 201110008322.7 has the content of organic solvents of 35-65 wt% and the content of curing agent of 1-3.5 wt%. These coatings use different types of solvents and curing agents to meet the needs of dispersion and curing of the semi-liquid system. However, these liquid coatings have relatively large restrictions on raw material selection, high raw material costs, and complex manufacturing processes.

[0005] On the other hand, many equipment manufacturers have developed various coating robots to coat the semi-liquid coating on the surface of ordinary ACSR conductors. Although their operating parameters are different, the common features of their structures include coating extrusion and storage components. The coating tank disclosed in the patent application No. 201810302387.4 includes a storage tank, an extrusion tank, and an extrusion motor. A pushing piston is arranged at the bottom of the feeding cover, and the pushing piston is connected to the bottom of the feeding cover through an elastic component. The extrusion tank is provided with a spiral feeding screw; a device for forming and coating the raw materials of cable insulation on the surface of a cable during high-altitude walking is disclosed in the patent application No. 201811639987.6, which includes a feeding mechanism such as a storage tank, an extrusion tank, and an extrusion motor, and has a substrate and four carrying units respectively arranged on the inner side of the substrate and each used for carrying and fixing a glue tank. The power transmission part is used to provide the power for extrusion of the glue tank extrusion part. Among them, the power transmission device consists of two motors, two driving sprockets, four driven sprockets, and a transmission chain. It can be seen from these coating robot designs that in order to achieve airtight storage and smooth coating of the semi-liquid coating, it is necessary to install supporting equipment with relatively large weight and volume. The increase in weight will increase the power burden of the robot. Especially in the case of relying on the battery system for high-altitude operations, the machine weight directly determines the coating speed, standby time, and climbing angle; the increase in volume will reduce the balance of the robot on the cable, and it is easily interfered by factors such as strong winds when walking.

[0006] Therefore, it is necessary to design a lightweight flame-retardant insulating coil for direct coating of overhead bare conductors, so as to solve the defects of high cost, complex process and great operation difficulty of liquid / semi-liquid coatings in the prior art. Summary of the Invention

[0007] The present invention provides a SEBS / PET lightweight flame-retardant insulating coil and its preparation method and application, so as to solve at least one of the many defects existing in the prior art described above.

[0008] In view of this, the solution of the present invention is as follows:

[0009] In the first aspect of the present invention, a SEBS / PET lightweight flame-retardant insulating coil is proposed, and its components by weight include: 40-60 parts of hydrogenated styrene-butadiene block copolymer (SEBS), 5-15 parts of polyethylene terephthalate (PET), 5-10 parts of plasticizer, 5-10 parts of flame retardant, 5-10 parts of stabilizer, 5-10 parts of antioxidant, 3-5 parts of dispersant and 1-3 parts of adhesive.

[0010] Further, the molecular weight of the hydrogenated styrene-butadiene block copolymer is 80,000-120,000, the content of styrene structural units is 20-40%, and the content of butadiene structural units is 60-80%. Preferably, the content of styrene structural units is 30%, the molecular weight is 100,000, and its melt flow rate range under the action of a 2.16 Kg weight at 230 °C is 5-10 g / 10 min.

[0011] Further, the molecular weight of the polyethylene terephthalate is 20,000-35,000, the molecular weight is preferably 30,000, the molecular weight distribution is 1.5-4.5, and its melt flow rate range under the action of a 2.16 KG weight at 250 °C is 1.5-4.5 g / 10 min.

[0012] Further, the plasticizer is naphthenic oil, selected from at least one of ethylene glycol dinaphthenate, diisononyl cyclohexane-1,2-dicarboxylate and butyl naphthenate, and materials such as saponified salts of zinc or lead that can cause an increase in conductivity are not used.

[0013] Further, the flame retardant is preferably a phosphorus-nitrogen type piperazine pyrophosphate-based flame retardant (piperazine pyrophosphate, pentaerythritol piperazine pyrophosphate, polyfocused piperazine pyrophosphate, etc., preferably pentaerythritol piperazine pyrophosphate), and polyammonium phosphate-based flame retardant materials with low water resistance and serious moisture absorption are not used. While ensuring good compatibility between the flame retardant and the substrate, the problems of low water resistance and serious moisture absorption are effectively avoided. Materials such as carbonates or hydroxides of aluminum or magnesium and stannates that can cause an increase in conductivity are not used as halogen-free flame retardants.

[0014] Further, the stabilizer is a mixture of insulating carbon black and piperidine derivatives; the insulating carbon black used plays the roles of coloring and strengthening, filling, and improving light stability to improve the material properties, while avoiding the reduction of the tensile strength and breakdown voltage of the material by fillers such as talcum powder, silica, and conductive carbon black. Preferably, the weight ratio of insulating carbon black to piperidine derivatives in the stabilizer is 3:2; the piperidine derivatives are selected from benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester, bis(2,2,6,6-tetramethyl-4-hydroxypiperidine) sebacate, and N,N'-bis(2,2,6,6-tetramethylpiperidinyl) hexamethylenediamine.

[0015] Further, the antioxidant is a phosphite antioxidant; preferably at least one of triphenyl phosphate, tris(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol bis(2,4-di-tert-butylphenyl) phosphite, which can play a synergistic role with the main flame retardant.

[0016] Further, the dispersant is a hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride, which can effectively improve the compatibility of various raw materials and avoid the occurrence of stretching and whitening phenomena.

[0017] Further, the binder is a silicone-based material, preferably at least one of polydimethylsiloxane, polymethylsiloxane, or vinyl polysiloxane.

[0018] The second aspect of the present invention lies in providing a preparation method for the SEBS / PET lightweight flame-retardant insulating coil described in the first aspect above, and the steps include:

[0019] Mix the preliminarily dried hydrogenated styrene-butadiene block copolymer, plasticizer, polyethylene terephthalate, flame retardant, stabilizer, antioxidant, dispersant, and binder evenly and perform deep drying;

[0020] Extrude and granulate the deeply dried material, and then perform plasticizing, molding, cooling, and winding to obtain the SEBS / PET lightweight flame-retardant insulating coil.

[0021] Further, the preliminary drying process is hot air drying at 80°C for 4 hours; the deep drying process is drying at 100°C for 2 - 6 hours.

[0022] Further, a twin-screw extruder is used in the extrusion granulation process, and five temperature control sections are set: the first temperature control section is 180 - 190°C, the second temperature control section is 190 - 220°C, the third temperature control section is 220 - 240°C, the fourth temperature control section is 220 - 240°C, the fifth temperature control section is 200 - 220°C, the screw speed is 55 r / min, and the main machine speed is 200 r / min.

[0023] Further, the twin-screw extruded pellets are placed in an oven and dried at 60°C for 4 hours.

[0024] Further, in the cooling process, the cooling roller of the casting machine is used to cool the extruded semi-finished product. The calendering speed is controlled so that the extrusion swelling ratio of the obtained coil is below 0.15, and the following calendering effects are controlled: the swelling ratio in the width direction is below 0.25, the shrinkage ratio in the thickness direction is below 0.25, and the difference between the swelling ratio in the width direction and the shrinkage ratio in the thickness direction is below 0.30.

[0025] Further, the calendering speed is 1 - 5 m / min.

[0026] The third aspect of the present invention lies in the application of the SEBS / PET lightweight flame-retardant insulating coil described in the first aspect above or the SEBS / PET lightweight flame-retardant insulating coil prepared by the preparation method described in the second aspect in coating the bare conductor of the cable.

[0027] Further, the bare conductor of the cable is used for overhead lines. The coating process uses a coil wrapping machine, specifically an on-line automatic robot. The SEBS / PET lightweight flame-retardant insulating coil can achieve rapid adhesion (within 3 seconds) in the range of 90 - 120°C, and exhibits good heat shrinkage in a lower temperature range (60 - 80°C), so that it can be coated on the surface of the cable wire energy-efficiently, tightly, and hermetically.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The lightweight flame-retardant insulating coil provided by the present invention meets the performance requirements such as breakdown voltage resistance (the breakdown voltage resistance can reach 30 kV / mm, the service life can reach more than 10 years, and in practical applications, the 2-mm-thick coil can meet the one-way-to-ground insulation requirements of 110 kV high-voltage cables), adhesion, elasticity, weather resistance, and dielectric loss. At the same time, its density is lower than that of coating materials, and since there is no solvent volatilization, the material quality is the same as the coating layer quality, which can effectively improve the material utilization rate and thus reduce the application cost; it can be directly made into a solid coil, and compared with liquid / semi-liquid coating materials, it does not require a surface drying time, and uses its own heat shrinkage to achieve uniform and tight coating on the conductor, so it can meet the outdoor construction conditions in a wider humidity and temperature range; the density of the coil is lower than 1 g / cm 3 , and the load force applied to the insulation of the bare conductor is small, which is convenient for the coating operation of overhead bare conductors, and has a broad application prospect.

[0030] The effective storage time of the SEBS / PET lightweight flame-retardant insulation coil of the present invention is greatly extended, from 6 - 10 months to more than ten years; it can be placed openly, is convenient for transportation, will not cause harm when directly contacted by the human body, and will not cause environmental impacts such as solvent volatilization, paint dripping, and leakage during use; it uses a low-temperature lamination system to replace paint extrusion, without considering storage conditions and the self-weight of the container, which reduces the overall weight of the coil covering operation device, showing greater cost and process advantages compared with the traditional coating process.

[0031] In the manufacturing process of existing SEBS / PET composites, the addition of halogen-free flame retardants such as inorganic salts of ammonium polyphosphate, carbonates or hydroxides of zinc, aluminum, and magnesium, stannates, etc. will increase the conductivity of the material. On the other hand, widely used fillers such as talcum powder, silica, titanium dioxide, etc. will reduce the tensile strength and breakdown voltage of the material. Therefore, in the material formula of the present invention, as much as possible, the mechanical properties and insulation properties of the material are considered. For example, insulating carbon black is used to play the role of coloring, reinforcing, filling, and improving light stability to improve the material properties; by adding nitrogen- or oxygen-containing polymers with good organic compatibility, the flammability of the material is effectively reduced and the flame retardant grade is improved.

[0032] By selecting the ratio of the two monomers and the molecular weight of SEBS and PET in the present invention, the base material has good mechanical properties and processing properties. The preferred ratio of the two monomers and the molecular weight of SEBS make the rigid chain segment of PET and the SEBS molecules wind more tightly. When impacted, the tip stress of the crack propagation of SEBS will be released by the relatively rigid PET particles, so the crack propagation is hindered and the impact resistance is improved; and PET has good chemical resistance and good processing fluidity, which can significantly improve the processability and low-temperature resistance of the product; the ratio of each component of the product is a choice based on the comprehensive performance of the product. If the PET content is too much, the material elongation is insufficient and the hardness is too large. If the PET content is too little, the heat deformation performance becomes poor. If the SEBS content is too much, the uncoiling force of the material will be too large, increasing the traction force and possibly affecting the heat deformation performance. If the SEBS content is too little, it is difficult to form a continuous phase or a bicontinuous phase, it is difficult to reduce the processing temperature of SEBS, and it is impossible to effectively achieve interlayer adhesion at a lower temperature, and it is also difficult for the new coil to achieve rapid (within 3 seconds) adhesion in the range of 90 - 120°C and show good heat shrinkage in the range of 60 - 80°C, so as to be tightly wrapped on the surface of the cable. If the contents of the flame retardant, stabilizer, antioxidant, and binder are too much, it will affect the mechanical properties, and if too little, the corresponding effects will not be achieved. The present invention flexibly regulates the structure, type, and content of each component to meet different requirements of the product. Specific embodiments

[0033] The technical solutions of the present invention will be clearly and completely described below in conjunction with preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] Unless otherwise specified, the reagents used in the examples were purchased commercially in this field, and the experimental means used were those familiar to those skilled in the art.

[0035] Example 1

[0036] The formulation of the SEBS / PET lightweight flame-retardant insulation coil is as follows: 40 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 40%, the molecular weight is 120,000, and the melt flow rate is 10 g / 10 min), 5 parts of polyethylene terephthalate (the molecular weight is 20,000, and the melt flow rate is 1.5 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pentaerythritol pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant tris(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0037] Process conditions:

[0038] (1) Weigh the raw materials such as hydrogenated styrene-butadiene block copolymer, polyethylene terephthalate, flame retardant, stabilizer, antioxidant, dispersant, and adhesive that have been dried by hot air (80 °C, 4 h) according to the experimental ratio, mix them evenly with a high-speed mixer, and then use a dehumidifying dryer to deeply dry them at 100 °C for 2 - 6 h.

[0039] (2) Use a twin-screw extruder to granulate. Set five temperature control sections. The first temperature control section is 180 - 190 °C, the second temperature control section is 190 - 220 °C, the third temperature control section is 220 - 240 °C, the fourth temperature control section is 220 - 240 °C, the fifth temperature control section is 200 - 220 °C, the screw speed is 55 r / min, and the main machine speed is 200 r / min; after strand pelletizing, put it into an oven and dry it at 60 °C for 4 h; the obtained pellets are subjected to double-roll plasticizing and molded into a coil (temperature 155 - 180 °C). Use the cooling roller of the casting machine to fully cool the extruded semi-finished product, and at the same time control the calendering speed, extend the loading time of the material during the cooling process, fully maintain the lateral ductility of the material, and finally wind, cut, and package to obtain the SEBS / PET lightweight flame-retardant insulation coil.

[0040] Example 2

[0041] The formulation of the SEBS / PET lightweight flame-retardant insulating coil is as follows: 60 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 20%, the molecular weight is 80,000, and the melt flow rate is 5 g / 10 min), 15 parts of polyethylene terephthalate (the molecular weight is 35,000, and the melt flow rate is 4.5 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pentaerythritol pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant tris(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0042] The process conditions are the same as those in Example 1.

[0043] Example 3

[0044] The formulation of the SEBS / PET lightweight flame-retardant insulating coil is as follows: 50 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 30%, the molecular weight is 100,000, and the melt flow rate is 7.5 g / 10 min), 10 parts of polyethylene terephthalate (the molecular weight is 30,000, and the melt flow rate is 3 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pentaerythritol pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant tris(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0045] The process conditions are the same as those in Example 1.

[0046] Example 4

[0047] The formulation of the SEBS / PET lightweight flame-retardant insulating coil is as follows: 50 parts of ethylene-vinyl acetate copolymer (the content of styrene structural unit is 30%, the molecular weight is 115,000, and the melt flow rate is 9 g / 10 min), 10 parts of polyethylene terephthalate (the molecular weight is 32,500, and the melt flow rate is 4 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant tris(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0048] The process conditions are the same as those in Example 1.

[0049] Example 5

[0050] The formulation of the SEBS / PET lightweight flame-retardant insulation coil is as follows: 50 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 35%, the molecular weight is 110,000, and the melt flow rate is 8 g / 10 min), 10 parts of polyethylene terephthalate (the molecular weight is 35,000, and the melt flow rate is 4.5 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanoate, 8 parts of flame retardant polyphosphoric acid piperazine, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0051] The process conditions are the same as those in Example 1.

[0052] Example 6

[0053] The formulation of the SEBS / PET lightweight flame-retardant insulation coil is as follows: 50 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 30%, the molecular weight is 100,000, and the melt flow rate is 7.5 g / 10 min), 10 parts of polyethylene terephthalate (the molecular weight is 27,000, and the melt flow rate is 2.5 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanoate, 5 parts of flame retardant pentaerythritol pyrophosphate piperazine salt, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant pentaerythritol bis(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0054] The process conditions are the same as those in Example 1.

[0055] Example 7

[0056] 50 parts of hydrogenated styrene-butadiene block copolymer (the content of styrene structural unit is 25%, the molecular weight is 110,000, and the melt flow rate is 8 g / 10 min), 10 parts of polyethylene terephthalate (the molecular weight is 25,000, and the melt flow rate is 2 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanoate, 10 parts of flame retardant pentaerythritol pyrophosphate piperazine salt, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester), 5 parts of antioxidant pentaerythritol bis(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, and 2 parts of adhesive polymethylsiloxane.

[0057] The process conditions are the same as those in Example 1.

[0058] Example 8

[0059] 50 parts of hydrogenated styrene-butadiene block copolymer (content of styrene structural unit: 30%, molecular weight: 115,000, melt flow rate: 9 g / 10 min), 10 parts of polyethylene terephthalate (molecular weight: 30,000, melt flow rate: 3 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pentaerythritol pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of bis(2,2,6,6-tetramethyl-4-hydroxypiperidyl) sebacate), 5 parts of antioxidant pentaerythritol bis(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, 2 parts of adhesive polymethylsiloxane.

[0060] The process conditions are the same as those in Example 1.

[0061] Example 9

[0062] 50 parts of hydrogenated styrene-butadiene block copolymer (content of styrene structural unit: 30%, molecular weight: 100,000, melt flow rate: 7.5 g / 10 min), 10 parts of polyethylene terephthalate (molecular weight: 30,000, melt flow rate: 3 g / 10 min), 8 parts of plasticizer ethylene glycol dicyclohexanecarboxylate, 8 parts of flame retardant piperazine pentaerythritol pyrophosphate, 10 parts of stabilizer (6 parts of insulating carbon black, 4 parts of N,N'-bis(2,2,6,6-tetramethylpiperidyl) hexanediamine), 5 parts of antioxidant pentaerythritol bis(2,4-di-tert-butylphenyl) phosphite, 3 parts of dispersant hydrogenated styrene-butadiene block copolymer grafted maleic anhydride, 2 parts of adhesive polymethylsiloxane.

[0063] The process conditions are the same as those in Example 1.

[0064] Comparative Example 1

[0065] Differing from Example 3, 30 parts of hydrogenated styrene-butadiene block copolymer.

[0066] The process conditions are the same as those in Example 1.

[0067] Comparative Example 2

[0068] Differing from Example 3, 70 parts of hydrogenated styrene-butadiene block copolymer.

[0069] The process conditions are the same as those in Example 1.

[0070] Comparative Example 3

[0071] Different from Example 3, 3.5 parts of polyethylene terephthalate.

[0072] The process conditions are the same as those in Example 1.

[0073] Comparative Example 4

[0074] Different from Example 3, 20 parts of polyethylene terephthalate.

[0075] The process conditions are the same as those in Example 1.

[0076] Comparative Example 5

[0077] Different from Example 3, 2 parts of flame retardant.

[0078] The process conditions are the same as those in Example 1.

[0079] Comparative Example 6

[0080] Different from Example 3, 12 parts of flame retardant

[0081] The process conditions are the same as those in Example 1.

[0082] Comparative Example 7

[0083] Different from Example 3, 8 parts of flame retardant (6 parts of ammonium polyphosphate, 2 parts of magnesium hydroxide).

[0084] The process conditions are the same as those in Example 1.

[0085] Performance Test

[0086] The material performance tests were carried out under the test conditions of a temperature of 25 ± 1 °C and a relative humidity of 40 ± 5%, and the following standards or methods were specifically implemented:

[0087] 1. The polymer density was measured according to ISO1183 and is expressed in g / cm.

[0088] 2. The bond strength was measured according to AFERA4001 using a 5 mm wide test strip at a 180° peel angle, and an AFERA standard steel plate was used as the test substrate.

[0089] 3. The unrolling force was measured according to DINEN1944 under the condition of 100 mm / min.

[0090] 4. The thermal stability was measured based on the method of ISO 6722.

[0091] 5. The low-temperature test was based on the method of ISOlDIS6722. The sample was wound around a paper tube shaft with a diameter of 10 cm and left standing at a certain temperature for 5 hours, and then the roll was visually inspected for defects such as cracks.

[0092] 6. The breakdown voltage is measured according to ASTM D149, and the value taken is the highest voltage that the specimen can withstand within one minute.

[0093] 7. Combustion performance test: Wrap the specimen around the No. 5 ACSR. In a non-ventilated room, fix it vertically and ignite it with the outer flame of a flame from below for 10 seconds. If the ACSR self-extinguishes within 10 seconds, the test is passed.

[0094] 8. Stretch whitening: Use a tensile testing machine to stretch a 5m long sample to 150% of its original length at a rate of 10 cm / minute, and then measure it visually.

[0095] 9. Mechanical properties: Use a tensile testing machine to measure the mechanical properties according to GB / T 1040.1-2018.

[0096] 10. Degree of aging: Use a xenon lamp aging chamber. According to GBT16422.2-2014, irradiate it under the xenon lamp for 5000h, and use a tensile testing machine to measure the mechanical properties after aging according to GB / T 1040.1-2018.

[0097] For the light-weight flame-retardant insulation rolls obtained in the above Examples 1-9 and Comparative Examples 1-7, performance tests were carried out, and the results are shown in Table 1 and Table 2 respectively.

[0098] Table 1:

[0099]

[0100] Table 2:

[0101]

[0102]

[0103] Based on the test results in Table 1 and Table 2, the following conclusions are drawn:

[0104] 1) The SEBS / PET light-weight flame-retardant insulation rolls proposed in Examples 1-9 have good mechanical and flame-retardant properties while meeting the performance requirements such as adhesion, elasticity, and dielectric loss. Their breakdown voltage resistance can reach 30 kV / mm (in actual applications, 2mm thick rolls can meet the single-phase to ground insulation requirements of 110KV high-voltage cables). After aging for 5000h under the xenon lamp (equivalent to 10 years of outdoor aging), their mechanical properties decrease by less than 35%, which can meet the usage requirements, and their theoretical storage and service life can both reach more than 10 years. Example 3 is a preferred example of the present invention compared to other examples. By flexibly regulating the structure, type, and content of each component, the best performance is achieved.

[0105] 2) The difference between Comparative Example 1 and Example 3 is that in Example 3, the hydrogenated styrene-butadiene block copolymer is preferably 50 parts, while in Comparative Example 1 it is 30 parts. By regulating the content of the hydrogenated styrene-butadiene block copolymer, the disadvantage of insufficient elongation of the substrate is improved.

[0106] 3) The difference between Comparative Example 2 and Example 3 is that in Example 3, the hydrogenated styrene-butadiene block copolymer is 50 parts, while in Comparative Example 2 it is 70 parts. By regulating the content of the hydrogenated styrene-butadiene block copolymer, the disadvantages of too large unwinding force of the substrate and increased traction are improved.

[0107] 4) The difference between Comparative Example 3 and Example 3 is that in Example 3, the polyethylene terephthalate is 10 parts, while in Comparative Example 3 it is 4.5 parts. By regulating the content of the polyethylene terephthalate, the disadvantage of poor heat deformation performance of the substrate is improved.

[0108] 5) The difference between Comparative Example 4 and Example 3 is that in Example 3, the polyethylene terephthalate is 10 parts, while in Comparative Example 4 it is 20 parts. By regulating the content of the polyethylene terephthalate, the bonding strength and mechanical properties of the substrate are improved.

[0109] 6) The difference between Comparative Example 5 and Example 3 is that in Example 3, the flame retardant is 8 parts, while in Comparative Example 5 it is 2 parts. Being too small results in poor flame retardant effect of the substrate.

[0110] 7) The difference between Comparative Example 6 and Example 3 is that in Example 3, the flame retardant is 8 parts, while in Comparative Example 6 it is 12 parts. Being too high results in poor mechanical properties, poor bonding strength and poor low temperature resistance of the substrate.

[0111] 8) The difference between Comparative Example 7 and Example 3 is that in Example 3, the flame retardant is 8 parts of pentaerythritol pyrophosphate piperazine salt, while in Comparative Example 7, the flame retardant is 8 parts which is 6 parts of ammonium polyphosphate and 2 parts of magnesium hydroxide. Due to the moisture absorption of ammonium polyphosphate and the conductivity of magnesium hydroxide, the weather resistance and withstand voltage of the substrate are greatly reduced.

[0112] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A SEBS / PET lightweight flame-retardant insulating coil, characterized in that, The components include, by weight: 40-60 parts of hydrogenated styrene-butadiene block copolymer, 5-15 parts of polyethylene terephthalate, 5-10 parts of plasticizer, 5-10 parts of flame retardant, 5-10 parts of stabilizer, 5-10 parts of antioxidant, 3-5 parts of dispersant and 1-3 parts of adhesive.

2. The SEBS / PET lightweight flame-retardant insulating coil according to claim 1, wherein The molecular weight of the hydrogenated styrene-butadiene block copolymer is 80,000-120,000, the content of styrene structural units is 20-40%, and the content of butadiene structural units is 60-80%. And / or, the molecular weight of the polyethylene terephthalate is 20,000-35,000.

3. The SEBS / PET lightweight flame-retardant insulating coil according to claim 1, wherein The plasticizer is naphthenic oil, selected from at least one of ethylene glycol diester of naphthenic acid, diisononyl cyclohexane 1,2-dicarboxylate and butyl naphthenate; And / or, the flame retardant is a phosphorus-nitrogen type piperazine pyrophosphate flame retardant, selected from at least one of piperazine pyrophosphate, pentaerythritol piperazine pyrophosphate salt, and polypyrazine pyrophosphate.

4. The SEBS / PET lightweight flame-retardant insulating coil according to claim 1, wherein The stabilizer is a mixture of insulating carbon black and a piperidine derivative; And / or, the antioxidant is a phosphite antioxidant; and / or, the dispersant is hydrogenated styrene-butadiene block copolymer grafted with maleic anhydride; And / or, the adhesive is siloxane.

5. The SEBS / PET lightweight flame-retardant insulation coil according to claim 4, wherein The weight ratio of insulating carbon black and piperidine derivative in the stabilizer is 3:2; the piperidine derivative is selected from benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, sebacate bis (2,2,6,6-tetramethyl-4-hydroxypiperidinyl), N, N'-bis (2,2,6,6-tetramethylpiperidinyl) hexanediamine; The phosphite antioxidant is selected from at least one of triphenyl phosphate, tris(2,4-di-tert-butylphenyl)phosphite and / or pentaerythritol di(2,4-di-tert-butylphenyl) bisphosphite; The siloxane is selected from at least one of polydimethylsiloxane, polymethylsiloxane or vinyl polysiloxane.

6. The preparation method of the SEBS / PET lightweight flame-retardant insulating coil according to any one of claims 1-5, characterized in that the steps include: The preliminarily dried hydrogenated styrene-butadiene block copolymer, plasticizer, polyethylene terephthalate, flame retardant, stabilizer, antioxidant, dispersant and adhesive are mixed evenly and deeply dried; The deeply dried material is extruded into granules, plasticated, molded, cooled and rolled to obtain SEBS / PET lightweight flame-retardant insulation coils.

7. The preparation method according to claim 6, characterized in that, The extrusion granulation process uses a twin-screw machine, and five temperature control sections are set: the first temperature control section is 180-190°C, the second temperature control section is 190-220°C, the third temperature control section is 220-240°C, the fourth temperature control section is 220-240°C, the fifth temperature control section is 200-220°C, the screw speed is 55r / min, and the main machine speed is 200r / min; And / or, the cooling process uses the cooling roller of the casting machine to cool the extruded semi-finished product, controls the calendering speed, makes the extrusion expansion ratio of the obtained coil below 0.15, and controls the following calendering effects: the expansion ratio in the width direction is below 0.25, the shrinkage ratio in the thickness direction is below 0.25, and the difference between the expansion ratio in the width direction and the shrinkage ratio in the thickness direction is below 0.

30.

8. The preparation method according to claim 7, wherein The calendering speed is 1-5 m / min.

9. Application of the SEBS / PET lightweight flame-retardant insulating coil described in any one of claims 1-5 or the SEBS / PET lightweight flame-retardant insulating coil prepared by the preparation method described in any one of claims 6-8 in coating a bare cable conductor.

10. The application according to claim 9, wherein The bare cable conductor is used for an overhead line, and a coil wrapping machine is used in the coating process.

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