Low-temperature-resistant PVC (polyvinyl chloride) cable material as well as preparation method and application thereof

Abstract

The invention relates to the field of high polymer materials, in particular to a low-temperature-resistant PVC cable material and a preparation method and application thereof. The low-temperature-resistant PVC cable material comprises the following components in parts by weight: 40-50 parts of polyvinyl chloride resin powder, 12-17 parts of calcium carbonate, 32-38 parts of a composite plasticizer and 8-12 parts of a processing aid, the composite plasticizer is composed of a polyester plasticizer containing aromatic rings or conjugated double bonds, a cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fibers and polyester fibers in a weight ratio of (1-3): (4-8): (1-1.5): (0.5-1): 1. The low-temperature-resistant PVC cable material with the formula has the characteristics of low temperature resistance, ultraviolet resistance and acid corrosion resistance, also has high strength in-55 DEG C extremely cold and acid rain regions, can effectively prevent acid rain erosion, effectively avoids aging and cracking phenomena, prolongs the service life of the PVC cable material, and meets the use requirements in-55 DEG C extremely cold and acid rain regions.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high polymer materials, in particular to a low-temperature-resistant PVC cable material and a preparation method and application thereof. BACKGROUND

[0002] In the technical field of cable materials, PVC cable materials are widely used, especially in the field of wind power cable sheath. With the rapid development of the wind power industry, the performance requirements of cable materials are also increasing. As an important part of the cable, the performance of the cable material directly affects the service life and safety of the cable. Good cable material can effectively protect the conductor inside the cable and prevent external environmental factors from damaging the cable, thereby ensuring the stability and safety of power transmission. In recent years, the wind power industry is developing towards larger power and more complex environmental applications, which puts forward more stringent performance requirements for cable materials.

[0003] In the industry, in order to prepare PVC cable materials, different formulations and process preparation methods are usually used to meet different performance requirements. From the formulation, some formulations will focus on adding plasticizers to improve the flexibility and processing performance of the cable material, making the cable more convenient during bending and installation. Commonly used plasticizers include dioctyl phthalate; some formulations will add stabilizers to enhance the thermal stability of the cable material and prevent decomposition and aging in high temperature environments, such as lead salt stabilizers, calcium-zinc composite stabilizers, etc.; in addition, some fillers will also be added to reduce costs and improve certain physical properties of the cable material, such as calcium carbonate, talc, etc. In the process preparation method, the various raw materials are usually mixed in a certain proportion, then preliminary mixing is carried out by a banbury mixer, and then melt extrusion granulation is carried out by a single screw or double screw extruder. These conventional means to some extent solve the basic performance problems of the flexibility, thermal stability, etc. of the cable material.

[0004] However, the existing PVC cable material has obvious defects in actual application. The main problem is that the existing PVC cable material is used in wind power cable harness, especially in the extremely low temperature and acid rain in the northern region. In the environment of long-term extremely low temperature and high intensity ultraviolet radiation, the existing PVC cable material is easily corroded by acid rain and has aging and cracking problems. The existing PVC cable material cannot meet the use requirements in extremely cold environments. SUMMARY

[0005] In order to improve the cold resistance, acid corrosion resistance and ultraviolet resistance of the PVC cable material, ensure that the PVC cable material can be used in extremely cold and acid rain environments for a long time, and effectively avoid the aging and cracking of the PVC cable material, a low-temperature-resistant PVC cable material and a preparation method and application thereof are provided.

[0006] The first aspect of the present application provides a low-temperature-resistant PVC cable material, which comprises the following components in parts by weight: 40-50 parts of polyvinyl chloride resin powder, 12-17 parts of calcium carbonate, 32-38 parts of a composite plasticizer, and 8-12 parts of a processing aid; the composite plasticizer is composed of a polyester plasticizer containing aromatic rings or conjugated double bonds, a cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fiber, and polyester fiber in a weight ratio of (1-3):(4-8):(1-1.5):(0.5-1):1.

[0007] By adopting the above technical solution, the polyvinyl chloride resin powder is used as a basic material to provide the cable material with basic physical properties and processing performance. The calcium carbonate can reduce the cost and improve some physical properties of the cable material. In the composite plasticizer, the polyester plasticizer containing aromatic rings or conjugated double bonds has good plasticizing effect and migration resistance, which can increase the flexibility and processing performance of the cable material; the cold-resistant plasticizer can significantly improve the flexibility and anti-brittle ability of the cable material in a low-temperature environment, so that the cable material can still maintain good performance in an extremely cold environment; the polytetrafluoroethylene has excellent chemical stability, corrosion resistance, and low friction coefficient, which can enhance the acid corrosion resistance and ultraviolet resistance of the cable material; the alkali-free glass fiber has high strength, high temperature resistance, and good insulation performance, which can improve the mechanical strength and dimensional stability of the cable material; the polyester fiber has high strength and modulus, which can further enhance the mechanical properties of the cable material. The alkali-free glass fiber, the polyester fiber, and the polytetrafluoroethylene synergistically play a role, so that the cable material can maintain good flexibility in a low-temperature environment and avoid brittle cracking due to low temperature; and the cable material can effectively resist the damage of ultraviolet rays and prevent the cable material from easily cracking due to aging. The PVC cable material can effectively avoid acid rain erosion even in an extremely cold environment of -55℃ and an acid rain environment for a long time. In summary, the low-temperature-resistant PVC cable material of the formula has the characteristics of low-temperature resistance, ultraviolet resistance, and acid corrosion resistance, has high strength, can effectively prevent acid rain erosion and aging cracking, prolongs the service life of the PVC cable material, and meets the use requirements in an extremely cold environment of -55℃ and an acid rain area.

[0008] Preferably, the cold-resistant plasticizer is composed of an aliphatic dibasic acid ester plasticizer, a polymer plasticizer, and / or an epoxidized plasticizer.

[0009] By adopting the technical scheme, the aliphatic dibasic acid ester plasticizer has good low-temperature performance, the molecular structure thereof can maintain good fluidity and flexibility at low temperature, the glass transition temperature of the cable material can be reduced, and the cable material can still maintain toughness at low temperature environment; the polymer plasticizer has large molecular weight and good compatibility, can form a stable structure with the polyvinyl chloride resin, and enhances the cohesive strength and stability of the cable material, and further improves the physical performance of the cable material at low temperature; the epoxidized plasticizer not only has a certain plasticizing effect, but also reacts with unstable chlorine atoms in the polyvinyl chloride molecules, and plays a stabilizing and anti-aging role. The cold-resistant plasticizer composed of these plasticizers is applied to the low-temperature-resistant PVC cable material, can significantly improve the cold resistance of the cable material, and makes the cable material applicable to extremely cold environment, avoiding aging and cracking problems at low temperature.

[0010] Preferably, the aliphatic dibasic acid ester plasticizer uses at least one of dioctyl sebacate, dioctyl adipate and dioctyl azelate.

[0011] By adopting the technical scheme, at least one of dioctyl sebacate, dioctyl adipate and dioctyl azelate is used as the aliphatic dibasic acid ester plasticizer, and these plasticizers have good cold resistance. The molecular structure thereof can effectively reduce the intermolecular force of the polyvinyl chloride resin, and the molecular chain is more easily moved. In extremely cold environment, this characteristic makes the cable material still maintain good flexibility and elasticity, avoiding hardening and cracking caused by low temperature. At the same time, they synergistically act with other components, further improve the comprehensive performance of the low-temperature-resistant PVC cable material in extremely cold and acid rain areas, and meet the demand of use in-55℃ extremely cold and acid rain areas.

[0012] Preferably, the inorganic glass fiber contains titanium dioxide, zirconium oxide, copper oxide and iron oxide components.

[0013] By adopting the technical scheme, the titanium dioxide, zirconium oxide, copper oxide and iron oxide are introduced into the alkali-free glass fiber, the titanium dioxide has good chemical stability and ultraviolet absorption capacity, can effectively resist the damage of ultraviolet to the cable material; the zirconium oxide can improve the hardness and wear resistance of the material, and enhance the physical properties of the cable material; the copper oxide and iron oxide have certain corrosion resistance, and can enhance the ability of the cable material to resist acid rain corrosion. The characteristics of these substances make the low-temperature-resistant PVC cable material better resist corrosion, aging and cracking in the extreme environment of long-term extremely low temperature cold and high-intensity ultraviolet radiation, and possible acid rain, and improve the durability and service life of the cable material in extremely cold environment. Preferably, the preparation method of the alkali-free glass fiber is: raw material mixing: quartz sand, aluminum oxide, limestone, dolomite, titanium dioxide, zirconium oxide, copper oxide and iron oxide powder are mixed according to the formula proportion, and are uniformly mixed by a ball mill to obtain a mixture; high-temperature melting: the mixture is put into a high-temperature melting furnace, and is heated in stages to form a uniform molten liquid; fiber forming: the molten liquid is discharged through a platinum-gold sieve plate to form a fine stream, and the fine stream is pulled by a rotating wire winding drum to be drawn into continuous glass fiber.

[0014] By adopting the technical scheme, the titanium dioxide, zirconium oxide, copper oxide and iron oxide are introduced into the alkali-free glass fiber, the titanium dioxide has good chemical stability and ultraviolet absorption capacity, can effectively resist the damage of ultraviolet to the cable material; the zirconium oxide can improve the hardness and wear resistance of the material, and enhance the physical properties of the cable material; the copper oxide and iron oxide have certain corrosion resistance, and can enhance the ability of the cable material to resist acid rain corrosion. The characteristics of these substances make the low-temperature-resistant PVC cable material better resist corrosion, aging and cracking in the extreme environment of long-term extremely low temperature cold and high-intensity ultraviolet radiation, and possible acid rain, and improve the durability and service life of the cable material in extremely cold environment. Preferably, the preparation method of the alkali-free glass fiber is: raw material mixing: quartz sand, aluminum oxide, limestone, dolomite, titanium dioxide, zirconium oxide, copper oxide and iron oxide powder are mixed according to the formula proportion, and are uniformly mixed by a ball mill to obtain a mixture; high-temperature melting: the mixture is put into a high-temperature melting furnace, and is heated in stages to form a uniform molten liquid; fiber forming: the molten liquid is discharged through a platinum-gold sieve plate to form a fine stream, and the fine stream is pulled by a rotating wire winding drum to be drawn into continuous glass fiber.

[0015] Preferably, the processing aid is composed of stabilizers, antioxidants, flame retardants and colorants.

[0016] By adopting the technical scheme, the processing aid is composed of stabilizers, antioxidants, flame retardants and coloring agents. The stabilizers can enhance the thermal stability of the cable material, prevent decomposition and aging in a high-temperature environment; the antioxidants can inhibit the oxidation reaction of the cable material with oxygen, delay the aging speed; the flame retardants can endow the cable material with flame retardant performance, reduce the danger in case of fire; and the coloring agents can make the cable material have a specific color for easy identification and differentiation. The functions of these components comprehensively improve the thermal stability, oxidation resistance and flame retardance of the low-temperature-resistant PVC cable material, and the cable material also has the characteristics of easy identification, thereby improving the performance and safety of the cable material in actual application and meeting the use requirements in extremely cold, acid rain and other harsh environments.

[0017] In a second aspect, a method for preparing the low-temperature-resistant PVC cable material comprises the following steps: S1. adding polyvinyl chloride resin powder, calcium carbonate, composite plasticizer and processing aid in a proportion according to a formula into a stirrer, and then adding them into a mixing machine, and first mixing at 110-120℃ for 5-8 minutes, and then mixing at 140-150℃ for 10-20 minutes to obtain a mixture; and S2. transferring the mixture into a granulator, and extruding and granulating the mixture by temperature rising at each section to obtain cable material particles.

[0018] By adopting the technical scheme, the polyvinyl chloride resin powder, calcium carbonate, composite plasticizer and processing aid are first added into a stirrer according to a formula, and then are put into a mixing machine, and are first mixed at 110-120℃ for 5-8 minutes. This temperature and time setting can make the raw materials preliminarily mixed uniformly at a relatively low temperature, so as to avoid premature reaction or decomposition of part of the raw materials due to high temperature. Then, the temperature is raised to 140-150℃ for mixing for 10-20 minutes. The higher temperature can make the raw materials further fully react and form a mixture with stable performance. The mixture is transferred into a granulator, and is extruded and granulated by temperature rising at each section. Such a step-by-step temperature rising and granulating process can ensure that the material is properly treated at different stages, so that the cable material particles obtained finally have good uniformity and stability, and the quality of the low-temperature-resistant PVC cable material is ensured, and the low-temperature resistance, anti-aging performance and corrosion resistance of the cable material in extremely cold, acid rain and other harsh environments are improved.

[0019] Preferably, the temperature rising at each section of the granulator in S2 is as follows: the temperature of a feeding section is controlled to be 80-100℃, the temperatures of plasticizing sections of the granulator are 100-110℃, 110-130℃ and 120-135℃ respectively, and the temperature of a discharging section of the granulator is 110-100℃.

[0020] By adopting the above technical scheme, the temperature of each section of the granulator is strictly controlled, the temperature of the feeding section is 80-100℃, the lower temperature can preliminarily preheat the material and keep a certain fluidity, and premature melting and bonding are avoided; the temperature of the plasticizing section is 100-110℃, 110-130℃ and 120-135℃ respectively, the temperature is gradually increased in stages, which can make the material fully plasticize, and the polyvinyl chloride resin powder, calcium carbonate, composite plasticizer and processing aid are uniformly dispersed and fused, so that the performance of the cable material is uniform and stable; the temperature of the discharging section is 110-100℃, and the appropriate temperature reduction can make the cable material maintain a good shape during extrusion molding, and prevent excessive deformation. Such precise temperature control can prepare the low-temperature-resistant PVC cable material particles with good performance and stable quality, so that the cable material has better low-temperature resistance and corrosion resistance in the extremely cold and acid rain area at-55℃, and can effectively avoid aging and cracking problems in extreme environment, and meet the use requirements in extremely cold environment.

[0021] In a third aspect, the application provides the use of the low-temperature-resistant PVC cable material in an extremely cold and acid rain area at-55℃. By adopting the above technical scheme, the material performance of the low-temperature-resistant PVC cable material is further optimized through specific temperature and time mixing and temperature increasing and granulation extrusion of each section of the granulator, and the low-temperature-resistant PVC cable material has good flexibility, thermal stability and mechanical properties. Therefore, the low-temperature-resistant PVC cable material can be applied in an extremely cold and acid rain area at-55℃, and can effectively avoid corrosion by acid rain and aging and cracking problems, so as to ensure the service life and safety of the cable in extreme environment, and meet the use requirements in extremely cold environment.

[0022] In summary, the application has at least one of the following beneficial technical effects: 1. The polyvinyl chloride resin powder, calcium carbonate, composite plasticizer and processing aid are combined according to specific weight proportions, the composite plasticizer is composed of polyester plasticizer containing aromatic ring or conjugated double bond, cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fiber and polyester fiber in a specific weight ratio, the polytetrafluoroethylene, alkali-free glass fiber and polyester fiber of the composite plasticizer play a synergistic role with the polyester plasticizer and cold-resistant plasticizer, which can effectively improve the low-temperature resistance, ultraviolet resistance and acid corrosion resistance of the cable material, has high strength, can effectively prevent acid rain erosion and aging and cracking, and meets the use requirements in an extremely cold and acid rain area at-55℃; 2. The preparation method of the low-temperature-resistant PVC cable material mixes the material uniformly through different temperature sections of the mixer, and then granulates and extrudes the cable material particles through different temperature sections of the granulator, so as to further optimize the low-temperature resistance, ultraviolet resistance and acid corrosion resistance of the cable material particles. DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with examples.

[0024] Introduction of some raw materials: Polyvinyl chloride resin powder, manufacturer: Wuhan Xindongyi Chemical Co., Ltd., CAS number: 9002-86-2; Polypropylene glycol adipate, manufacturer: Wuhan Shur Biological Technology Co., Ltd., CAS number: 25101-03-5; Polytetrafluoroethylene (Japan DuPont brand), supplier: Shanghai Hemocheng Plastic Co., Ltd., model: C-5200; Polyester fiber, manufacturer: Taian Hongfa New Material Co., Ltd., specification: 6mm; Alkali-free glass fiber, manufacturer: Taian Hongfa New Material Co., Ltd., specification: 50mm; Di-octyl terephthalate, manufacturer: Zhengzhou Yufeng Nanometer Material Co., Ltd., molecular formula: C57H106O10; Di-octyl sebacate, manufacturer: Zhengzhou Yufeng Nanometer Material Co., Ltd.; Calcium-zinc stabilizer, manufacturer: Wuhan Xindongyi Chemical Co., Ltd., packaging specification: 200kg; Antimony trioxide, manufacturer: Zhengzhou Boxuan Chemical Products Co., Ltd., packaging specification: 25kg; Antioxidant, manufacturer: Tianjin Li'anlong New Material Co., Ltd., CAS number: 10081-67-1; Colorant, manufacturer: Jinan Rongzheng Chemical Co., Ltd., CAS number: 1314-13-2. Embodiment

[0025] Embodiment 1

[0026] A low-temperature-resistant PVC cable material is prepared by the following method: S1: 40kg of chloroethylene resin powder, 17kg of calcium carbonate, 38kg of composite plasticizer and 8kg of processing aid are added to a mixer, and then added to a mixer, first mixed at 110℃ for 5 minutes, and then mixed at 140℃ for 20 minutes to obtain a mixture; S2: The mixture obtained in S1 is transferred to a granulator, and the granulator is heated by controlling the temperature of each section of the granulator: the feeding section temperature is 80℃, the plasticizing section temperature of the granulator is 100℃, 120℃ and 135℃ respectively, and the discharge section temperature of the granulator is 110℃, and the cable material particles are obtained by extrusion granulation.

[0027] The composite plasticizer used in this embodiment is composed of polyester plasticizer containing aromatic ring or conjugated double bond, cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fiber and polyester fiber in a weight ratio of 3:8:1:0.5:1.

[0028] The polyester plasticizer containing aromatic ring or conjugated double bond in the embodiment is dioctyl terephthalate.

[0029] The cold-resistant plasticizer in the embodiment is composed of aliphatic dibasic acid ester plasticizer and polymer plasticizer in a weight ratio of 1:1, the aliphatic dibasic acid ester plasticizer is dioctyl sebacate, and the polymer plasticizer is polypropylene adipate.

[0030] The processing aid in the embodiment is composed of stabilizer, antioxidant, flame retardant, and colorant in a weight ratio of 1:1:1:1. The stabilizer is calcium-zinc stabilizer, and the flame retardant is antimony trioxide.

[0031] Example 2-3 Example 2-3 is different from Example 1 in that the raw material formula and amount of polyvinyl chloride resin powder, calcium carbonate, composite plasticizer, and processing aid are different, as shown in Table 1:

[0032] Table 1 Raw material amount (kg) of Examples 1-3

[0033] Example 4-5 Example 4-5 is different from Example 1 in that the raw material formula and amount of polyester plasticizer containing aromatic ring or conjugated double bond, cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fiber, and polyester fiber in the composite plasticizer are different, as shown in Table 2: Table 2 Weight ratio of raw material formula amount of Examples 1, 4-5

[0034] Example 6

[0035] Example 6 is different from Example 1 in that the alkali-free glass fiber in the embodiment is an alkali-free glass fiber into which titanium dioxide, zirconium oxide, copper oxide, iron oxide, and the like are introduced; wherein the alkali-free glass fiber used in the embodiment is prepared by the following method: Raw material mixing: mix quartz sand, aluminum oxide, limestone, dolomite, titanium dioxide, zirconium oxide, copper oxide, and iron oxide powder in a weight ratio of 280:70:100:30:2.5:10:1.5:1, and mix them uniformly through a ball mill to obtain a mixture; High-temperature melting: put the mixture into a high-temperature melting furnace, and heat in stages: preheating section: 300℃, remove moisture and volatile matter: decomposition section: 800℃, decompose carbonate into oxide: melting section: 1400℃, to form a uniform molten liquid; Fiber forming: the molten liquid flows out through a platinum-gold sieve plate to form a fine stream, which is drawn into continuous glass fiber by a rotating wire winding drum.

[0036] Comparative Example Comparative Example 1 Comparative Example 1 differs from Example 1 in that the polytetrafluoroethylene is replaced by an equivalent amount of alkali-free glass fiber.

[0037] Comparative Example 2 Comparative Example 2 differs from Example 1 in that the polyester fiber is replaced by an equivalent amount of alkali-free glass fiber.

[0038] Comparative Example 3 Comparative Example 3 differs from Example 1 in that the polytetrafluoroethylene is replaced by an equivalent amount of alkali-free glass fiber.

[0039] Comparative Example 4 Comparative Example 4 differs from Example 1 in that the cold-resistant plasticizer is replaced by an equivalent amount of polyester plasticizer.

[0040] Comparative Example 5 Comparative Example 5 differs from Example 1 in that the polyester plasticizer is replaced by an equivalent amount of cold-resistant plasticizer.

[0041] Performance Test The PVC cable material particles obtained in Examples 1-6 and Comparative Examples 1-5 were injected by an injection molding machine at a temperature of 160°C to obtain a plurality of pipe test samples, and the corresponding pipe test samples were used to test the low-temperature resistance, ultraviolet resistance, acid corrosion resistance, and tensile breaking strength of the pipes. The specific data are shown in Table 3.

[0042] Detection Method / Test Method Tensile strength test: The tensile strength of the pipe test samples of Examples 1-6 and Comparative Examples 1-5 was directly tested according to GB / T 8804.2-2003, with the unit being MPa: Low-temperature resistance test: The impact catalytic temperature test of the pipe test samples of Examples 1-6 and Comparative Examples 1-5 was performed according to the GB / T 5470 standard requirement for “Plastics - Determination of brittleness temperature by impact”, with the unit being °C; Ultraviolet resistance test: The ultraviolet resistance test of the pipe test samples of Examples 1-6 and Comparative Examples 1-5 was performed according to GB / T 16422.3-2022 “Plastics - Laboratory light source exposure test - Part 3: Fluorescent UV lamps”, with the experimental conditions being: illumination stage: 0.76 W / m² @ 340 nm, 60°C, for 12-18 hours; condensation stage: 50°C, humidity, for 4 hours, and then the tensile strength test of the pipe test samples of Examples 1-6 and Comparative Examples 1-5 was performed, with the tensile strength ≥ 20 MPa being recorded as qualified, and the tensile strength < 20 MPa being recorded as unqualified; Acid corrosion resistance test: the pipe test samples of examples 1-6 and comparative examples 1-5 were immersed in 5% sulfuric acid solution at -55℃ for 100 hours, then taken out, washed to neutral, dried, and then the tensile breaking strength of each pipe test sample was tested, and those with tensile strength ≥ 20 MPa were considered qualified, and those with tensile strength < 20 MPa were considered unqualified; the experimental data of examples 1-6 and comparative examples 1-5 are shown in table 3.

[0043] Table 3 experimental data of examples 1-6 and comparative examples 1-5

[0044] Analysis of experimental results Comparative analysis of examples 1-6: Among them, the impact strength of example 2 is the highest, which is 23.8 MPa, and the impact embrittlement temperature is the lowest, which is -60℃. Although increasing the amount of polyvinyl chloride resin powder in example 3 can improve rigidity, it will reduce toughness, resulting in a decrease in impact strength. Reducing the amount of calcium carbonate in example 2 can improve the flexibility of the material and achieve a balance between rigidity and toughness, indicating that the formulation ratio of example 2 is the optimal combination, which can simultaneously improve the impact resistance and low temperature toughness. Among them, the impact embrittlement temperature of example 5 is the lowest, which is -62℃, and the impact strength is relatively high, which is 24.0 MPa. Although reducing the amount of dioctyl terephthalate in example 4 can improve the impact strength, it will reduce the ultraviolet resistance. Increasing the amount of polytetrafluoroethylene in example 5 can significantly improve the chemical corrosion resistance and ultraviolet resistance, and improve the low temperature toughness. It is indicated that the formulation ratio of example 5 is the optimal combination, which can simultaneously improve the low temperature toughness and environmental aging resistance.

[0045] Comparative analysis of example 1 and comparative examples 1-5: By comparing the performance data of the above examples 1 and comparative examples 1-5, the key role of polyester plasticizer, cold resistance plasticizer, polytetrafluoroethylene, alkali-free glass fiber and polyester fiber in PVC cable material can be clearly obtained, especially the synergistic effect of polytetrafluoroethylene, alkali-free glass fiber and polyester fiber.

[0046] After replacing the alkali-free glass fiber with polytetrafluoroethylene in comparative example 1, the impact strength before aging was tested, which decreased from 23.2 MPa to 17.3 MPa, with a decrease of 25.4%. The impact embrittlement temperature increased from -55℃ to -45℃, and the low temperature performance decreased significantly. The ultraviolet resistance test was unqualified, and the acid corrosion resistance was also unqualified. It is obvious that the absence of alkali-free glass fiber leads to a decrease in material rigidity and impact resistance. It is indicated that polytetrafluoroethylene cannot completely replace the ultraviolet resistance and acid corrosion resistance of alkali-free glass fiber, and long-term use is prone to aging cracking.

[0047] The impact strength before aging of Comparative Example 2, in which polyester fiber is replaced by alkali-free glass fiber, is tested, and the impact strength decreases from 23.2 MPa to 17.6 MPa, a decrease of 24.1%; the impact embrittlement temperature increases from -55°C to -48°C, and the low-temperature performance decreases; and the ultraviolet resistance and acid corrosion resistance are both unqualified. It can be seen that the absence of polyester fiber weakens the toughness and environmental aging resistance of the material, and although alkali-free glass fiber can enhance rigidity, it cannot make up for the contribution of polyester fiber in ultraviolet resistance and acid corrosion resistance.

[0048] The impact strength before aging of Comparative Example 3, in which polytetrafluoroethylene is replaced by alkali-free glass fiber, is tested, and the impact strength decreases from 23.2 MPa to 18.6 MPa, a decrease of 19.8%; the impact embrittlement temperature increases from -55°C to -43°C, and the low-temperature performance deteriorates significantly; and the ultraviolet resistance and acid corrosion resistance are both unqualified. It shows that the absence of polytetrafluoroethylene leads to a significant decrease in the chemical corrosion resistance and ultraviolet resistance of the material, and although alkali-free glass fiber can provide certain rigidity, it cannot replace the protective effect of polytetrafluoroethylene.

[0049] The impact strength before aging of Comparative Example 4, in which cold-resistant plasticizer is replaced by polyester plasticizer, is tested, and the impact strength decreases from 23.2 MPa to 20.2 MPa, a decrease of 12.9%; the impact embrittlement temperature increases from -55°C to -21°C, and the low-temperature performance deteriorates severely; although the ultraviolet resistance is qualified, the acid corrosion resistance is still unqualified. It shows that the absence of cold-resistant plasticizer leads to insufficient low-temperature toughness of the material, and although polyester plasticizer can provide certain ultraviolet resistance, it cannot make up for the role of cold-resistant plasticizer in low-temperature environments.

[0050] The impact strength before aging of Comparative Example 5, in which polyester plasticizer is replaced by cold-resistant plasticizer, is tested, and the impact strength decreases from 23.2 MPa to 21.0 MPa, a decrease of 9.5%; the impact embrittlement temperature increases from -55°C to -38°C, and the low-temperature performance decreases; and the ultraviolet resistance is qualified, but the acid corrosion resistance is still unqualified. It shows that the absence of polyester plasticizer leads to a decrease in the acid corrosion resistance of the material, and although cold-resistant plasticizer can improve the low-temperature performance, it cannot replace the chemical corrosion resistance of polyester plasticizer.

[0051] In summary, the synergistic effect of polytetrafluoroethylene, alkali-free glass fiber, and polyester fiber is significant, and all three play a key role in ultraviolet resistance and acid corrosion resistance, and none of them can be omitted. The absence of any one of them will lead to the easy occurrence of aging cracking of the material during long-term use, and all three must work together to achieve better comprehensive performance of low-temperature resistance, ultraviolet resistance, acid corrosion resistance, and high strength, so that the material can effectively resist acid rain erosion and prevent aging cracking during long-term use, and meet the use requirements in extremely cold and acid rain areas at -55°C.

[0052] The specific embodiments are only illustrative of the application and are not intended to limit the scope of the application. Any modifications of the embodiments made by those skilled in the art without inventive effort shall fall within the scope of the patent law as long as they are within the scope of the claims of the application.

Claims

1. A low temperature resistant PVC cable compound, characterized in that, By weight parts comprising the following components: polyvinyl chloride resin powder 40-50 parts, calcium carbonate 12-17 parts, composite plasticizer 32-38 parts, processing aid 8-12 parts; the composite plasticizer is composed of polyester plasticizer containing aromatic ring or conjugated double bond, cold-resistant plasticizer, polytetrafluoroethylene, alkali-free glass fiber and polyester fiber in a weight ratio of (1-3):(4-8):(1-1.5):(0.5-1):

1.

2. The low temperature resistant PVC cable compound according to claim 1, wherein, The cold-resistant plasticizer is composed of aliphatic dibasic acid ester plasticizer, polymer plasticizer and / or epoxidized plasticizer.

3. The low temperature resistant PVC cable compound according to claim 2, wherein, The aliphatic dibasic acid ester plasticizer uses at least one of dioctyl sebacate, dioctyl adipate, dioctyl azelate.

4. The cold-resistant PVC cable compound according to claim 1, characterized in that, The inorganic glass fiber contains titanium dioxide, zirconium oxide, copper oxide, iron oxide components.

5. The low temperature resistant PVC cable compound according to claim 4, wherein, The preparation method of the alkali-free glass fiber is: Raw material mixing: mix quartz sand, alumina, limestone, dolomite, titanium dioxide, zirconium oxide, copper oxide, iron oxide powder according to the formula proportion, mix uniformly by ball mill to get the mixture; High temperature melting: put the mixture into high temperature melting furnace, heat in stages to form uniform molten liquid; Fiber forming: the molten liquid flows out through platinum gold sieve plate to form fine stream, which is drawn into continuous glass fiber by rotating wire drawing cylinder.

6. The cold-resistant PVC cable compound according to claim 1, wherein, The processing aid is composed of stabilizer, antioxidant, flame retardant, colorant.

7. A process for the preparation of a cold-resistant PVC cable compound according to any one of claims 1 to 6, characterized in that, Including the following steps: S1 add polyvinyl chloride resin powder, calcium carbonate, composite plasticizer, processing aid in the proportion of formula in the blender, add to the mixing mill, first mix at 110-120℃ for 5-8 minutes, then heat to 140-150℃ for 10-20 minutes to get the mixture; S2 transfer the mixture to the granulator, the granulator is extruded and granulated by temperature rising of each section to get the cable granules.

8. A process for the preparation of a low temperature resistant PVC cable compound according to claim 7, characterized in that, The temperature rising of each section of the granulator in S2 is: the feeding section temperature is controlled at 80-100℃, the plasticizing section temperature of the granulator is 100-110℃, 110-130℃ and 120-135℃ respectively, and the discharge section temperature of the granulator is 110-100℃.

9. The application of the low-temperature-resistant PVC cable material of any one of claims 1-8 in-55℃ extremely cold and acid rain area.

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