High flame-retardant oil-resistant PVC composition, preparation method and application thereof

Abstract

The present application relates to a kind of high flame-retardant oil-resistant PVC compositions and its preparation method and application, it includes the following weight parts of raw material components: polyvinyl chloride resin 100 parts;Plasticizer 60-75 parts;Cold resistance modifier 5-8 parts;Heat stabilizer 5-10 parts;Calcium carbonate 15-25 parts;Flame retardant synergist 15-25 parts;Butyronitrile rubber powder 5-20 parts;Toughening agent 3-5 parts;Ultraviolet absorber 0.2-0.8 parts.By the synergistic cooperation of each component, both high flame-retardant (oxygen index>32) can be met, and also through oil test (100 ℃×24h), while having excellent low temperature performance (-45 ℃).

Description

Technical Field

[0001] This invention belongs to the field of cable material technology, and relates to a PVC composition, specifically a high flame retardant and oil-resistant PVC composition, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC) materials are widely used in automotive wiring harness protection due to their excellent flame retardancy, electrical insulation, and low cost. However, with the increasingly complex environment of automotive engine compartments, rising temperatures, and increased opportunities for contact with oil contaminants (such as lubricating oil and brake fluid), traditional PVC materials face challenges.

[0003] In existing technologies, pure PVC materials have poor oil resistance and are prone to swelling, leading to a decrease in insulation performance. On the other hand, adding a large amount of plasticizer to improve low-temperature performance can result in a decrease in heat distortion temperature and a deterioration in oil resistance. Furthermore, in order to achieve a high flame retardant rating (such as an oxygen index >32), a large amount of inorganic flame retardants are often required, which can seriously impair the mechanical properties and processing fluidity of the material.

[0004] Chinese invention patent application number 202210989265.3 discloses a high flame-retardant, ceramizable PVC environmentally friendly cable material and its preparation method. The cable material comprises the following components in parts by weight: 100 parts PVC resin powder, 20-40 parts polymer plasticizer, 2.5-10 parts cold-resistant plasticizer, 40-50 parts ceramizable powder, 2.5-5 parts flame retardant, 15-30 parts flame-retardant charring agent, 3.5-10 parts acid-base neutralizer, 4-6 parts stabilizer, 2.5-5 parts molding agent, and 0.5-0.8 parts lubricant. This high flame-retardant, ceramizable PVC environmentally friendly cable material has excellent high flame-retardant properties, but its oil resistance still needs improvement. Therefore, it is necessary to develop a PVC composition that can meet the requirements of high flame retardancy (oxygen index > 32), pass the oil resistance test (100℃ x 24h), and also possess excellent low-temperature resistance (-45℃). Summary of the Invention

[0005] In view of the shortcomings of existing technical approaches, the present invention aims to provide a highly flame-retardant and oil-resistant PVC composition.

[0006] To achieve the above objectives, the present invention provides a high flame-retardant and oil-resistant PVC composition, comprising the following raw material components in parts by weight: 100 parts of polyvinyl chloride resin; Plasticizer 60-75 parts; 5-8 parts of cold-resistant modifier; 5-10 parts heat stabilizer; 15-25 parts calcium carbonate; 15-25 parts of flame retardant synergist; 5-20 parts of nitrile rubber powder; 3-5 parts toughening agent; 0.2-0.8 parts of ultraviolet absorber.

[0007] Ideally, the polyvinyl chloride resin is a loose resin with an average degree of polymerization of 1300-1700.

[0008] Preferably, the plasticizer is a mixture of one or more components selected from diisononyl terephthalate and epoxidized soybean oil.

[0009] Ideally, the cold-resistant modifier is selected from CPE-135A.

[0010] Ideally, the heat stabilizer is a calcium-zinc composite environmentally friendly stabilizer.

[0011] Ideally, the calcium carbonate is heavy calcium carbonate.

[0012] Ideally, the flame retardant synergist is composed of antimony trioxide and zinc borate.

[0013] Ideally, the nitrile rubber powder has a particle size of 80-120 mesh and an acrylonitrile content of 20-25%.

[0014] Preferably, the toughening agent is a mixture of one or more components selected from ethylene terpolymers, and the ultraviolet absorber is UV-531.

[0015] Another object of the present invention is to provide a method for preparing the above-mentioned high flame retardant and oil-resistant PVC composition, comprising the following steps: (a) High-speed mixing: Add the polyvinyl chloride resin, plasticizer, cold-resistant modifier, heat stabilizer and ultraviolet absorber to a high-speed mixer according to the formula amount, and mix at 700-900 rpm for 3-5 minutes; (b) Heating and adding materials: When the temperature rises to 80-90℃, add calcium carbonate, flame retardant synergist, nitrile rubber powder and toughening agent, and continue to stir and mix; (c) Discharge: When the mixing temperature reaches 110-120℃, discharge the material to obtain the premix; (d) Extrusion granulation: The premixed material is fed into a twin-screw extruder and plasticized and extruded at a temperature of 140-160°C. The final composition is obtained by pelletizing.

[0016] Optimally, the process parameters of the twin-screw extruder are: main machine speed 200-300 rpm, feeding frequency 15-25 Hz, and vacuum degree -0.06 to -0.1 MPa.

[0017] A third objective of this invention is to provide an application of the above-mentioned high flame-retardant and oil-resistant PVC composition for manufacturing automotive wiring harness corrugated pipes, oil-resistant cable sheaths, or industrial conveyor belts.

[0018] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art: The high flame retardant and oil-resistant PVC composition of the present invention, through the synergistic cooperation of each component, can not only meet the requirements of high flame retardancy (oxygen index > 32) and pass the oil resistance test (100℃×24h), but also has excellent low temperature resistance (-45℃). Detailed Implementation

[0019] This invention relates to a high flame-retardant and oil-resistant PVC composition, comprising the following raw material components in parts by weight: 100 parts polyvinyl chloride resin; 60-75 parts plasticizer; 5-8 parts cold-resistant modifier; 5-10 parts heat stabilizer; 15-25 parts calcium carbonate; 15-25 parts flame-retardant synergist; 5-20 parts nitrile rubber powder; 3-5 parts toughening agent; and 0.2-0.8 parts ultraviolet absorber. Through the synergistic effect of these components, the composition achieves both high flame retardancy (oxygen index > 32) and passes the oil resistance test (100℃ × 24h), while also exhibiting excellent low-temperature resistance (-45℃).

[0020] The polyvinyl chloride resin is a loose resin with an average degree of polymerization of 1300-1700 (such as one or more combinations of Formosa Plastics US-70 / S-80 and Hanwha HG-1300). The plasticizer is a mixture selected from one or more of diisononyl terephthalate (DINT) and epoxidized soybean oil. The cold-resistant modifier is CPE (Shandong Rike CPE-135A is selected). The heat stabilizer is a calcium-zinc composite environmentally friendly stabilizer. The calcium carbonate is heavy calcium carbonate. The flame retardant synergist is composed of antimony trioxide and zinc borate (preferably in a mass ratio of 2:1-3:1, more preferably 3:1). The nitrile rubber powder has a particle size of 80-120 mesh and an acrylonitrile content of 20-25%. The toughening agent is a mixture selected from one or more of ethylene terpolymers (DuPont HP4051 is selected). The ultraviolet absorber is UV-531.

[0021] The preparation method of the above-mentioned high flame retardant and oil-resistant PVC composition includes the following steps: (a) High-speed mixing: Add the polyvinyl chloride resin, plasticizer, cold-resistant modifier, heat stabilizer, and ultraviolet absorber to a high-speed mixer according to the formula, and mix at 700-900 rpm for 3-5 minutes; (b) Heating and feeding: When the temperature rises to 80-90℃, add calcium carbonate, flame retardant synergist, nitrile rubber powder, and toughening agent, and continue stirring and mixing; (c) Discharging: When the mixing temperature reaches 110-120℃, discharge the material to obtain a premix; (d) Extrusion granulation: Feed the premix into a twin-screw extruder, plasticize and extrude at 140-160℃, and granulate to obtain the final composition. The process parameters of the twin-screw extruder are: main extruder speed 200-300 rpm, feeding frequency 15-25 Hz, and vacuum degree -0.06 to -0.1 MPa.

[0022] The above-mentioned high flame-retardant and oil-resistant PVC composition is used to manufacture automotive wiring harness corrugated pipes, oil-resistant cable sheaths, or industrial conveyor belts.

[0023] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in this industry.

[0024] Examples 1-5, Comparative Examples 1-6 Examples 1-5 and Comparative Examples 1-6 each provide a PVC composition and its preparation method, which adopts the formulation ratios in Table 1 (unit: kg) and further includes the following steps (the parameter ranges in the following steps have virtually no effect on the performance of the product): (a) High-speed mixing: Add polyvinyl chloride resin, plasticizer, cold-resistant modifier, heat stabilizer and ultraviolet absorber to a high-speed mixer according to the formula amount, and mix at 700-900 rpm for 3-5 minutes; (b) Heating and adding materials: When the temperature rises to 80-90℃, add calcium carbonate, flame retardant synergist, nitrile rubber powder and toughening agent, and continue to stir and mix; (c) Discharge: When the mixing temperature reaches 110-120℃, discharge the material to obtain the premix; (d) Extrusion granulation: The premixed material is fed into a twin-screw extruder and plasticized and extruded at a temperature of 140-160℃. The final composition is obtained by pelletizing. The process parameters of the twin-screw extruder are: main machine speed 200-300rpm, feeding frequency 15-25Hz, vacuum degree -0.06 to -0.1MPa.

[0025] Table 1. Product formulation composition of Examples 1-5 and Comparative Examples 1-6 (unit: kg)

[0026] Note: Calcium carbonate A is active heavy calcium carbonate (Lida LD-1000C); calcium carbonate B is inactive heavy calcium carbonate (Huahong A103); CPE (chlorinated polyvinyl chloride resin) is 135A; the flame retardant synergist is composed of antimony trioxide and zinc borate in a mass ratio of 3:1.

[0027] Table 2. Physical performance test results of the products in Examples 1-5 and Comparative Examples 1-6

[0028] Specifically, the particles obtained in step (d) are placed in a 170°C open mill for 5-7 minutes for thermoplasticization to produce sheets. The pre-plasticized sheets are then cut and placed in a flat vulcanizing machine, pressed at 170°C and 12.5 MPa to standard thickness samples for the required physical properties. These samples are tested at 1.0 mm (specific gravity / tensile strength / breaking strength / 20°C electrical resistance / oil resistance / aging) / 2.0 mm (low-temperature impact embrittlement temperature) / 3.0 mm (oxygen index) / 6.0 mm (hardness) for subsequent physical property tests. (Note: The 200°C thermal stability test uses the particles obtained in step (d) directly tested using the static Congo red method.) In Examples 1-5, based on the test results in Table 2, adjusting the normal dosages of vinyl chloride resin, plasticizer, calcium-zinc stabilizer, calcium carbonate, flame retardant synergist, and nitrile rubber powder has little impact on the physical properties of the materials, remaining within the normal range. Within the normal range, a higher dosage of calcium-zinc stabilizer results in a longer thermal stability time at 200℃.

[0029] Compared with Example 4, calcium carbonate B (non-active heavy calcium carbonate selected from Huahong A103) is prone to agglomeration. Its surface is hydrophilic and easily absorbs moisture, making it difficult to blend with oily organic resins, resulting in poor dispersibility in liquids.

[0030] Compared with Examples 3-5, Comparative Example 2 showed that the oxygen index was lower than the normal range, and the oil resistance tensile strength retention rate and oil resistance elongation at break retention rate of 902# oil did not meet the test requirements.

[0031] Compared to Example 4, Comparative Example 3 showed that the amount of flame retardant synergist was below the normal range, and the oxygen index of the material was also below the normal range. If the amount is too small, it cannot cover sufficient reaction sites, and the potential of the flame retardant synergist cannot be realized, failing to produce a strong synergistic effect and thus unable to achieve efficient flame retardancy by capturing free radicals and forming an isolation layer in the gas phase. Compared to Example 4, Comparative Example 4 showed that the amount of flame retardant synergist was above the normal range, and the material's low-temperature impact embrittlement temperature also failed to meet the requirements. This is because high amounts of flame retardant synergists (especially inorganic fillers) disrupt the continuity of the plastic matrix, making the material brittle and losing its original toughness, thus failing the low-temperature impact test.

[0032] Compared with Example 4, Comparative Example 5 showed that the amount of plasticizer was lower than the normal range, and the tensile strength of the material was lower than the required value. The molecular chains were loosely connected, and when subjected to tensile force, the molecular chains were prone to slippage rather than absorbing energy through chemical bond breakage, resulting in low tensile strength and potentially abnormal elongation at break (usually smaller or abnormally larger but without strength).

[0033] Compared with Example 4, Comparative Example 6 showed that the amount of nitrile rubber powder used was lower than the normal range, and the oil retention rate of the material did not meet the requirements. Nitrile rubber powder is a copolymer of butadiene and acrylonitrile produced by low-temperature polymerization. It is a powdered elastomer made by a special process and has good resistance to oils and organic solvents, making it suitable for applications requiring contact with oils. The addition of nitrile rubber powder is usually to improve the material's oil resistance, heat resistance, and aging resistance. Without the addition of effective nitrile rubber powder, the oil resistance cannot meet high standards.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A highly flame-retardant and oil-resistant PVC composition, characterized in that, It comprises the following raw material components in parts by weight: 100 parts of polyvinyl chloride resin; Plasticizer 60-75 parts; 5-8 parts of cold-resistant modifier; 5-10 parts heat stabilizer; 15-25 parts calcium carbonate; 15-25 parts of flame retardant synergist; 5-20 parts of nitrile rubber powder; 3-5 parts toughening agent; 0.2-0.8 parts of ultraviolet absorber.

2. The high flame-retardant and oil-resistant PVC composition according to claim 1, characterized in that: The polyvinyl chloride resin is a loose resin with an average degree of polymerization of 1300-1700.

3. The high flame-retardant and oil-resistant PVC composition according to claim 1, characterized in that: The plasticizer is a mixture of one or more of diisononyl terephthalate and epoxidized soybean oil; the cold-resistant modifier is selected from CPE-135A; the heat stabilizer is a calcium-zinc composite environmentally friendly stabilizer; and the calcium carbonate is heavy calcium carbonate.

4. The high flame-retardant and oil-resistant PVC composition according to claim 1, characterized in that: The flame retardant synergist is composed of antimony trioxide and zinc borate.

5. The high flame-retardant and oil-resistant PVC composition according to claim 1, characterized in that: The nitrile rubber powder has a particle size of 80-120 mesh and an acrylonitrile content of 20-25%.

6. The high flame-retardant and oil-resistant PVC composition according to claim 1, characterized in that: The toughening agent is a mixture of one or more components selected from ethylene terpolymers, and the ultraviolet absorber is UV-531.

7. A method for preparing the high flame-retardant and oil-resistant PVC composition according to any one of claims 1 to 6, characterized in that, Includes the following steps: (a) High-speed mixing: Add the polyvinyl chloride resin, plasticizer, cold-resistant modifier, heat stabilizer and ultraviolet absorber to a high-speed mixer according to the formula amount, and mix at 700-900 rpm for 3-5 minutes; (b) Heating and adding materials: When the temperature rises to 80-90℃, add calcium carbonate, flame retardant synergist, nitrile rubber powder and toughening agent, and continue to stir and mix; (c) Discharge: When the mixing temperature reaches 110-120℃, discharge the material to obtain the premix; (d) Extrusion granulation: The premixed material is fed into a twin-screw extruder and plasticized and extruded at a temperature of 140-160°C. The final composition is obtained by pelletizing.

8. The method for preparing the high flame-retardant and oil-resistant PVC composition according to claim 7, characterized in that, The process parameters of the twin-screw extruder are: main machine speed 200-300 rpm, feeding frequency 15-25 Hz, and vacuum degree -0.06 to -0.1 MPa.

9. The application of the high flame-retardant and oil-resistant PVC composition according to any one of claims 1 to 6, characterized in that: Used to manufacture automotive wiring harness corrugated pipes, oil-resistant cable sheaths, or industrial conveyor belts.

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