Weather-resistant, cold-resistant, flame-retardant pvc sheath material composition and preparation method thereof

Abstract

The present application relates to the technical field of PVC sheath material, in particular to a weather-resistant and cold-resistant flame-retardant PVC sheath material composition and a preparation method thereof.The composition comprises the following raw materials by mass: 100 parts of polyvinyl chloride resin; 5-9 parts of composite calcium-zinc stabilizer; 47-59 parts of composite plasticizer; 0.25-0.55 parts of antioxidant; 0.05-0.15 parts of ultraviolet absorber; 21-29 parts of composite flame retardant; 0.3-0.7 parts of polyethylene wax; 0.3-0.7 parts of lubricant; 11-15 parts of calcium carbonate; and 1-3 parts of carbon black.The composite plasticizer is a mixture of DOA, TOTM and PTL; the plasticizer PTL used in the present application is an aliphatic plasticizer, which has high plasticizing efficiency, fast processing speed, low volatility and migration, and excellent ultraviolet stability; PTL has good synergistic plasticizing effect with DOA and TOTM, effectively improving the cold resistance and weather resistance of the sheath material.

Description

Technical Field

[0001] This invention relates to the field of PVC sheathing technology, specifically to a weather-resistant, cold-resistant, and flame-retardant PVC sheathing composition and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) is a polymer material with excellent mechanical and electrical insulation properties, especially its flame-retardant and self-extinguishing properties. This makes PVC widely used in cable material production and it has long held an important position in wire and cable insulation materials, being widely used in various types of wire and cable insulation and sheathing materials. However, with the rapid development of the national economy, cables are widely used in various power stations, wind turbines, charging piles, subway stations, power plants, high-rise buildings, military facilities, oil platforms, submarine cables, and other fields. The operating environment of cables is complex, therefore, the requirements for cable quality and function are becoming increasingly higher. Many wires and cables are used outdoors, enduring harsh climates such as wind, sun, and cold. Therefore, the cable sheathing material must be weather-resistant, cold-resistant, water-resistant, acid and alkali-resistant, and oil-resistant. Currently, existing cable sheathing materials are insufficient in terms of weather resistance to meet the requirements of some fields. During use, due to the complex environment encountered by the cable, the cable surface is prone to aging and wear. After aging and wear, the internal structural layers and even conductors are easily exposed, posing safety hazards and greatly increasing the risk of electric shock.

[0003] Chinese Patent CN 103113692 A discloses a cold-resistant, flame-retardant, and antistatic polyvinyl chloride (PVC) sheathing material for coal mine cables. It is characterized by being composed of the following raw materials: polyvinyl chloride resin SG3, tris(2-chloroethyl) phosphate, antistatic agent, dioctyl sebacate, dioctyl phthalate, tricresyl phosphate, antimony trioxide, zinc borate, tribasic lead sulfate, dibasic lead phosphite, light calcium carbonate, bisphenol A, 2-thiol-based benzoimidazole, vinyltris(β-methoxyethoxy)silane, accelerator TMTD, and modified asbestos powder. This PVC sheathed cable material exhibits low surface resistivity and high antistatic performance. The use of a composite high-concentration antistatic agent composed of TCEP and quaternary ammonium cationic surfactants and nonionic surfactants achieves a good synergistic antistatic effect, resulting in a surface resistivity ≤10⁸ Ω and excellent antistatic properties.

[0004] Chinese Patent CN 103524930 A discloses a cold-resistant PVC sheath material for cables and its preparation method, which is made from the following raw materials in weight fractions: SG-4 type polyvinyl chloride 75-95, chloroprene rubber 10-15, dioctyl phthalate 10-15, diisobutyl nylonate 5-10, ACR 4-7, ethylene bis-hard amide 2-3, dipropylene glycol dibenzoate 8-12, antioxidant 264 1-1.5, decabromodiphenyl ether 10-15, ammonium polyphosphate 5-10, dibasic lead phosphite 1-2, tribasic lead sulfate 1-2, barium stearate 2-3, epoxidized soybean oil 4-8, acetylene carbon black 20-30, titanium dioxide 3-6, calcined loess 5-10, activated calcium carbonate 10-15, and composite filler 4-6. The sheath material of this invention has high cold resistance, with a low-temperature impact catalytic temperature of -50℃, and still maintains excellent tensile strength, impact resistance, wear resistance, and aging resistance under low-temperature conditions.

[0005] Chinese Patent CN104861385A discloses a flame-retardant insulating polyvinyl chloride (PVC) cable sheath material, relating to the field of cable processing technology. It is made from the following raw materials in parts by weight: 80-90 parts PVC, 50-60 parts butyl rubber, 30-40 parts pentaerythritol, 5-15 parts trioctyl trimellitate, 10-20 parts chlorinated paraffin, 3-5 parts antioxidant, and 12-14 parts calcium carbonate. The beneficial effects of this invention are: a simple process flow, reasonable raw material ratio, providing suitable raw materials for cable sheath material production, strong flame-retardant properties, high insulation strength, better performance, and guaranteed cable product quality.

[0006] Chinese Patent CN 112194863A discloses an outdoor weather-resistant polyvinyl chloride (PVC) cable sheath material and its preparation method. The sheath material is made from the following raw materials in parts by weight: 30-50 parts polyvinyl chloride (PVC), 30-50 parts epoxy resin, 1-3 parts polyethylene wax, 10-20 parts graphene oxide, 1-3 parts antimony trioxide, 20-40 parts plasticizer, 10-15 parts stabilizer, and 1-5 parts triphenylphosphine. The epoxy resin is bisphenol A type epoxy resin; the weight ratio of the epoxy resin to the PVC is 1:1. This invention, by simultaneously introducing graphene and epoxy resin into the PVC cable material, and by chemically bonding the epoxy resin and graphene oxide before mixing them with the PVC cable material, fully ensures the uniformity of the mixing of all raw materials in the sheath material, effectively improving the mechanical properties and weather resistance of the PVC cable sheath material.

[0007] The cable sheath materials involved in the above four patents have single or dual properties in terms of cold resistance, flame retardancy, and weather resistance. None of them are cable sheath materials with more comprehensive cold resistance, flame retardancy, and weather resistance, and all have their limitations. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides a weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition, which has excellent properties such as cold resistance, flame retardancy, and weather resistance. This invention also provides its preparation method, which is scientific, reasonable, simple, and easy to implement.

[0009] A weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition, comprising the following raw materials in parts by weight:

[0010]

[0011] in:

[0012] The composite plasticizer is a mixture of dioctyl adipate (DOA), trioctyl trimellitate (TOTM), and pentaerythritol tetravalerate (PTL).

[0013] The mass ratio of the mixture of dioctyl adipate (DOA), trioctyl trimellitate (TOTM), and pentaerythritol tetravalerate (PTL) is (28–32):(13–17):(6–10), preferably (29–31):(14–16):(7–9).

[0014] The polyethylene resin is a PVC resin with an average degree of polymerization of 1700-2000, preferably an S-80 resin from Formosa Plastics Industrial (Ningbo) Co., Ltd. with an average degree of polymerization of 1700.

[0015] The preferred composite calcium-zinc stabilizer is RUP-127 composite calcium-zinc stabilizer from Adico Corporation of Japan, with an preferred dosage of 6 to 8 parts.

[0016] The antioxidant is a mixture of antioxidant 1010 and antioxidant 168.

[0017] The antioxidant 1010 is pentaerythritol tetrakis[methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) ester], and the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite ester 168. The mixing mass ratio of antioxidant 1010 and antioxidant 168 is (0.15-0.35):(0.1-0.2), preferably (0.2-0.3):(0.1-0.2).

[0018] The ultraviolet absorber is a benzotriazole light stabilizer, preferably UV-326, namely 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, and the preferred dosage is 0.08 to 0.12 parts.

[0019] The composite flame retardant is a mixture of aluminum hydroxide and antimony trioxide.

[0020] The mass ratio of aluminum hydroxide and antimony trioxide is (16-20):(5-9), preferably (17-19):(6-8).

[0021] The lubricant is polyethylene wax, a polyethylene oligomer with an average molecular weight of 4000-6000.

[0022] The calcium carbonate mentioned is active nano-calcium carbonate, and the preferred dosage is 12 to 14 parts.

[0023] The carbon black is produced by the furnace flue gas method, and the preferred dosage is 1 to 3 parts.

[0024] A method for preparing a weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition includes the following steps:

[0025] (1) Weigh the raw materials according to the formula, pour the weighed solid materials into the high-speed mixer and stir at high speed;

[0026] (2) When the material temperature reaches 75℃~80℃, stir at low speed, add the weighed composite plasticizer, mix at low speed for 1~2 minutes, and then adjust to high speed stirring.

[0027] (3) By observation, it was found that after the plasticizer was completely absorbed and the material was loose, it was discharged into the low-speed mixer, the stirring and cooling were started, the material was cooled down and then discharged, and the mixed material was granulated in a twin-screw extruder.

[0028] in:

[0029] The high-speed stirring speed is 1000-1400 rpm;

[0030] The low-speed stirring speed is 700-999 rpm;

[0031] Step (3) The material temperature is 45℃-55℃;

[0032] The parameters of the twin-screw extruder described in step (3) are set as follows:

[0033] Zones 1-3: 100℃-140℃

[0034] Zones 4-7: 150℃-170℃

[0035] Machine head: 163℃~167℃.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) The plasticizer used in this invention, pentaerythritol tetravalve ester (PTL), is an aliphatic plasticizer with high plasticizing efficiency, fast processing speed, low volatility migration, and excellent UV stability. PTL has a good synergistic plasticizing effect with dioctyl adipate (DOA) and trioctyl trimellitate (TOTM), which effectively improves the cold resistance and weather resistance of the sheath material.

[0038] (2) The aluminum hydroxide used in this invention has flame retardant, smoke suppression and filling effects, and has excellent dispersion performance. It has a good synergistic flame retardant effect with antimony trioxide. The addition of aluminum hydroxide effectively improves the flame retardancy and smoke suppression of the sheath material.

[0039] (3) The carbon black particles produced by the furnace smoke method are fine and have good dispersion properties, which can effectively improve the surface smoothness of the sheath material. Detailed Implementation

[0040] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0041] The polyvinyl chloride resins used in the examples and comparative examples were S-80, S-70, and S-85 resins, purchased from Formosa Plastics Industrial (Ningbo) Co., Ltd. The polyethylene wax was CH-4A type polyethylene wax, purchased from Shanghai Huayi Plastic Additives Factory.

[0042] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0043] Table 1. Formulation components (parts by weight) of weather-resistant, cold-resistant, and flame-retardant PVC cable sheath materials in Examples 1-5.

[0044]

[0045]

[0046] Comparative Examples 1-7 are control formulations, and the component ratios of the control formulations are shown in Table 2.

[0047] Table 2. Formulation components (parts by weight) of weather-resistant, cold-resistant, and flame-retardant PVC cable sheathing materials for Comparative Examples 1-7.

[0048]

[0049]

[0050] Weigh the samples according to the formula for the examples and comparative examples. Pour the weighed solid materials into a high-speed mixer and start high-speed stirring. When the material temperature reaches about 80°C, adjust to low speed and add the weighed composite plasticizer through the plasticizer inlet. Mix at low speed for 1-2 minutes, then adjust to high speed stirring and continue mixing for 4-6 minutes. After observing that the plasticizer is completely absorbed and the material is loose, discharge the material into a low-speed mixer and start stirring to cool. When the material temperature drops to about 50°C, discharge the material. The high-speed stirring speed is 1300 rpm and the low-speed stirring speed is 700 rpm.

[0051] The mixed materials were granulated in a twin-screw extruder, and the granulation parameters were set as shown in Table 3. The resulting PVC cable sheath material was then prepared into corresponding samples for performance testing.

[0052] Table 3 Granulator Parameter Settings

[0053]

[0054] The performance test results of the PVC cable sheathing material compositions in the examples and comparative examples are shown in Tables 4 and 5.

[0055] Table 4 Performance Comparison of PVC Cable Sheathing Material Compositions in Examples 1-5

[0056]

[0057] Table 5. Performance Comparison of PVC Cable Sheathing Compounds (Comparative Examples 1-7)

[0058]

[0059] As can be seen from the examples and comparative examples, Example 3 is the optimal formulation. Comparative Examples 3-5 show that the cold and weather resistance of cable sheath materials prepared by combining the three plasticizers in pairs is significantly less effective than the simultaneous application of all three plasticizers. The optimal ratio of the three plasticizers results in excellent cold and weather resistance for the PVC cable sheath material. Pentaerythritol tetravalve ester (PTL) is an aliphatic plasticizer with high plasticizing efficiency, fast processing speed, low volatility migration, and excellent UV stability. PTL exhibits a good synergistic plasticizing effect with the other two plasticizers, effectively improving the cold and weather resistance of the sheath material. The sheath material prepared from S-70 with an average degree of polymerization of 1300 demonstrates superior weather and cold resistance. The performance of cable sheathing materials prepared with S-80 resin with an average degree of polymerization of 1700 is inferior to that of materials prepared with S-85 resin with an average degree of polymerization of 2500. Cable sheathing materials prepared with S-85 resin have better weather resistance and cold resistance, but poor processing performance due to the high degree of polymerization. Aluminum hydroxide has flame retardant, smoke suppression, and filling effects, and has excellent dispersibility. It has a good synergistic flame retardant effect with antimony trioxide. The addition of aluminum hydroxide effectively improves the flame retardancy and smoke suppression of the sheathing material. Magnesium hydroxide has poor dispersibility. The synergistic flame retardant effect of aluminum hydroxide and antimony trioxide is better than that of magnesium hydroxide. Compared with ordinary carbon black, furnace smoke carbon black has finer particles and better dispersion, which can effectively improve the surface smoothness of the sheathing material.

Claims

1. A weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition, characterized in that, The raw materials include the following parts by weight: 100 parts of polyvinyl chloride resin; 5-9 parts of compound calcium-zinc stabilizer; 47-59 parts of compound plasticizer; Antioxidant 0.25~0.55 parts; 0.05~0.15 parts of ultraviolet absorber; 21-29 parts of composite flame retardant; Lubricant 0.3~0.7 parts; 11-15 parts calcium carbonate; 1-3 parts carbon black; in: The composite plasticizer is a mixture of dioctyl adipate (DOA), trioctyl trimellitate (TOTM), and pentaerythritol tetravalerate (PTL). The mass ratio of the mixture of dioctyl adipate (DOA), trioctyl trimellitate (TOTM), and pentaerythritol tetravalerate (PTL) is (28~32): (13~17): (6~10). The polyvinyl chloride resin mentioned is a PVC resin with an average degree of polymerization of 1700~2000; The composite flame retardant is a mixture of aluminum hydroxide and antimony trioxide, wherein the mass ratio of aluminum hydroxide to antimony trioxide is (16~20):(5~9).

2. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition according to claim 1, characterized in that, The antioxidant is a mixture of antioxidant 1010 and antioxidant 168.

3. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition according to claim 2, characterized in that, The mass ratio of antioxidant 1010 and antioxidant 168 is (0.15~0.35): (0.1~0.2).

4. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition according to claim 1, characterized in that, The ultraviolet absorber is a benzotriazole light stabilizer.

5. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition according to claim 1, characterized in that, The lubricant is a polyethylene wax with an average molecular weight of 4000-6000.

6. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing material composition according to claim 1, characterized in that, The calcium carbonate mentioned is active nano-calcium carbonate.

7. The weather-resistant, cold-resistant, and flame-retardant PVC sheathing composition according to claim 1, characterized in that, The carbon black mentioned is carbon black produced by the furnace flue gas process.

8. A method for preparing a weather-resistant, cold-resistant, flame-retardant PVC sheathing material composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Weigh the raw materials according to the formula, pour the weighed solid materials into the high-speed mixer and stir at high speed; (2) When the material temperature reaches 75℃~80℃, stir at low speed, add the weighed composite plasticizer, mix at low speed for 1~2 minutes, and then adjust to high speed stirring. (3) By observation, it was found that after the plasticizer was completely absorbed and the material was loose, it was discharged into the low-speed mixer, the stirring and cooling were started, the material was cooled down and then discharged, and the mixed material was granulated in the twin-screw extruder. in: The high-speed stirring speed is 1000~1400 rpm; The low-speed stirring speed is 700~999 rpm; Step (3) The material temperature is 45℃-55℃; The parameters of the twin-screw extruder described in step (3) are set as follows: Zones 1-3: 100℃~140℃ Zones 4-7: 150℃~170℃ Machine head: 163℃~167℃.

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