Corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particle and processing technology thereof

Abstract

The invention discloses corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particles and a processing technology thereof, and belongs to the field of electronics. 10-25 parts of a high-melting-point block copolymer plasticizer; 5-10 parts of a heat stabilizer with an aromatic heterocyclic structure; 8-20 parts of a multi-phase crosslinked elastomer blending material; 3-8 parts of an efficient chelating flame retardant; 2-6 parts of a fluorine modified corrosion-resistant additive; and 5-15 parts of a silane treated mineral filler. The preparation method comprises the following steps: S1, mixing the vinyl chloride resin with the aromatic heterocyclic structure heat stabilizer and the high-melting-point block copolymerization plasticizer; s2, adding the multi-phase cross-linked elastomer blending material and the fluorine-modified corrosion-resistant additive into the mixture, and continuously mixing; s3, adding the silane-treated mineral filler and the efficient chelating flame retardant into the mixture, and performing low-speed shearing and mixing; and S4, extruding, cooling and granulating. The PVC cable material has the beneficial effects that by optimizing the formula and the processing technology of the PVC cable material particles, the corrosion resistance and the high-temperature stability of the material are improved, the flexibility is considered, the service life of the cable is prolonged, and the reliability of the cable is improved.

Description

Technical Field

[0001] The present invention relates to the field of electronics, and more specifically, to a polyvinyl chloride cable material particle with corrosion resistance and high temperature resistance and its processing technology. Background Art

[0002] Polyvinyl chloride (PVC) cable material particles have been widely used in the wire and cable industry since the 1960s due to their good insulation, mechanical strength, and processability. With the acceleration of the industrialization process, higher requirements are put forward for the corrosion resistance and high temperature resistance of cable materials. In the early days, PVC cable materials mainly improved their performance by adding plasticizers, stabilizers, and flame retardants. However, plasticizers are prone to migration, and stabilizers such as lead salts are harmful to the environment and the human body, becoming limiting factors. Entering the 21st century, the technology has developed towards halogen-free environmental protection and enhanced thermal stability, and a variety of new thermal stabilizers (such as calcium-zinc, magnesium-zinc systems) and cross-linking modification methods have been developed. At the same time, nano-fillers and modified resins are introduced to improve thermal stability and corrosion resistance. These improvements have significantly extended the service life and reliability of PVC cable materials and met the application requirements in more demanding environments.

[0003] However, the biggest shortcoming of the current technology is that it is difficult to balance high temperature stability and flexibility. As the temperature rises, the PVC structure tends to decompose. Even if the heat resistance is improved through cross-linking modification or adding thermal stabilizers, it often leads to a decrease in the flexibility of the material, affecting the construction and use performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a polyvinyl chloride cable material particle with corrosion resistance and high temperature resistance and its processing technology to solve the problems mentioned in the above background art: However, the biggest shortcoming of the current technology is that it is difficult to balance high temperature stability and flexibility. As the temperature rises, the PVC structure tends to decompose. Even if the heat resistance is improved through cross-linking modification or adding thermal stabilizers, it often leads to a decrease in the flexibility of the material, affecting the construction and use performance.

[0005] Technical Solution: A polyvinyl chloride cable material particle with corrosion resistance and high temperature resistance, comprising the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10 - 25 parts of high melting point block copolymer plasticizer; 5 - 10 parts of aromatic heterocyclic structure thermal stabilizer; 8 - 20 parts of multiphase cross-linked elastomer blend material; 3 - 8 parts of highly efficient chelating type flame retardant; 2 - 6 parts of fluorine-modified corrosion-resistant additive; 5 - 15 parts of silane-treated mineral filler.

[0006] Preferably, the high melting point block copolymer plasticizer is made of a block polyester-polyether copolymer and has a chain segment structure with a melting point not lower than 180°C.

[0007] Preferably, the aromatic heterocyclic structure thermal stabilizer includes 2-benzothiazolopyridine compounds and bisphenol A derivatives, which are compounded in a weight ratio of 1:1.

[0008] Preferably, the multi-phase cross-linked elastomer blend material is composed of ethylene propylene diene monomer rubber and peroxide-cross-linked polyether ester thermoplastic elastomer, and the cross-linking degree is 50%-70%.

[0009] Preferably, the fluorine-modified corrosion-resistant additive is a compound of perfluoroalkyl sulfonate and fluorosilane, and the mass ratio is 3:2.

[0010] Preferably, the silane-treated mineral filler is talc powder modified by silane coupling agent KH-570, the particle size distribution is in the range of 1-3μm, and the treatment temperature is controlled at 120°C.

[0011] Preferably, a processing process for a corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particle comprises the following steps: S1. Mix polyvinyl chloride resin with an aromatic heterocyclic structure heat stabilizer and a high melting point block copolymer plasticizer in a mixer, control the temperature at 160-180°C, and the mixing time at 5-10 minutes to obtain a mixture; S2. Add the multi-phase cross-linked elastomer blend material and the fluorine-modified corrosion-resistant additive to the mixture, and continue mixing for 10 minutes; S3. Add the silane-treated mineral filler and the high-efficiency chelating flame retardant to the mixture, and perform low-speed shear mixing, control the temperature at 140-150°C, and the time at 3-5 minutes; S4. Extrude through a twin-screw extruder, cool and pelletize to obtain cable material particles.

[0012] Preferably, in S2, a high-frequency magnetron ultrasonic field-assisted dispersion technology is adopted, the frequency is 20-40kHz, and the action time is 3-6 minutes.

[0013] Preferably, in S3, a vacuum devolatilization treatment is performed to remove trace volatile monomers and unreacted substances in the system, the pressure is controlled at -0.08~-0.1MPa, and the time is 5 minutes.

[0014] Preferably, the cable material particles are heat-treated at 160°C for 2 hours.

[0015] Compared with the prior art, the advantages of the present invention are as follows: (1) Different from using phthalate plasticizers in the prior art, the present invention adopts a high melting point block copolymer plasticizer, which significantly improves the thermal stability and molecular chain flexibility of the plasticizing system, and inhibits the migration and volatilization phenomena at high temperatures while ensuring flexibility.

[0016] (2) Different from only adding non-polar polyolefin elastomers in the prior art, in the present invention, ethylene propylene diene monomer rubber and COPE thermoplastic elastomer are blended, and a continuous phase network is formed through cross-linking, improving the elastic modulus retention rate and stress recovery performance of the material in high-temperature environments.

[0017] (3) Different from using simple metal soap-based heat stabilizers in the prior art, in the present invention, heat stabilizers with aromatic heterocyclic structures are introduced. This type of stabilizer has functions such as antioxidant, inhibiting HCl release, and heat-resistant decomposition, effectively extending the service life of the material and increasing the thermal decomposition temperature.

[0018] (4) Different from the traditional formulations in the prior art that do not consider corrosion resistance, in the present invention, fluorine-modified corrosion-resistant additives are specifically added, which can construct a hydrophobic and oleophobic barrier structure on the surface of the PVC matrix, enhancing its dimensional stability and physical property retention rate in acid, alkali, salt water, and oil-polluted environments.

[0019] (5) Different from the single filler treatment method in the prior art, in the present invention, mineral reinforcing fillers are treated by silane coupling, and with the synergistic effect of a thermal reaction-type compatibilizer, the interfacial bonding force between the polar PVC matrix and the non-polar elastic phase is enhanced, avoiding performance degradation caused by weak phase boundaries.

[0020] (6) Different from using ordinary mixing-extrusion molding processes in the prior art, in the present invention, process steps such as magnetron ultrasonic dispersion, vacuum devolatilization, and post-treatment of thermal crystallization are introduced, not only improving the dispersion of fillers but also significantly reducing the influence of residual stress, bubbles, and volatiles on the insulation performance.

[0021] (7) Different from the limitations in the prior art that cannot simultaneously meet heat resistance and flexibility performance, in the present invention, through composite material design and synergistic reinforcement strategies, overall performance improvements are achieved in aspects such as the initial thermal decomposition temperature, elongation at break, and retention rate of hot air aging strength, solving the technical bottleneck of "flexibility - heat resistance - corrosion resistance" being difficult to balance. Description of the Drawings

[0022] Figure 1 It is a schematic flow chart of the processing technology of a corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particle of the present invention Detailed Embodiments

[0023] Examples Examples 1 - 4 Example 1: A corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particle, comprising the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10 - 25 parts of high-melting-point block copolymer plasticizer; 5 - 10 parts of heat stabilizer with aromatic heterocyclic structure; 8 - 20 parts of multi-phase cross-linked elastomer blend material; 3 - 8 parts of highly efficient chelating flame retardant; 2 - 6 parts of fluorine-modified corrosion-resistant additive; 5 - 15 parts of silane-treated mineral filler.

[0024] The preparation steps are as follows: S1. Mix polyvinyl chloride resin and a high melting point block copolymer plasticizer in a high-speed mixer for 10 minutes until pre-plasticized; S2. Add ethylene propylene diene monomer rubber, COPE elastomer, aromatic heterocyclic heat stabilizer, fluorine-modified additive and treated filler, and continue mixing for 15 minutes; S3. Treat the mixture with a magnetron ultrasonic dispersion device for 8 minutes; S4. Melt and extrude in a twin-screw extruder (temperature set at 170 - 185 °C), and the vacuum devolatilization section is set in the fourth section with a vacuum degree of -0.08 MPa; S5. The discharged material is cooled, drawn into strips, pelletized, and dried with hot air to obtain pellets.

[0025] Performance test results: Initial thermal decomposition temperature (TGA): ≥260 °C; Tensile strength: ≥15 MPa; Elongation at break: ≥230%; Dielectric strength: ≥20 kV / mm; Acid and alkali corrosion resistance (immersed in 10% NaOH and HCl for 72 h): Mass retention rate ≥98%; Tensile strength retention rate after thermal aging (136 °C, 168 h): ≥80% Example 2: The difference from Example 1 is that the dosage of the high melting point block copolymer plasticizer is adjusted to 50 parts; The COPE elastomer is increased to 6 parts; the aromatic heterocyclic heat stabilizer is increased to 3.5 parts; the other components and process steps are the same.

[0026] The test results are as follows: Initial thermal decomposition temperature: 263 °C Elongation at break: 245% Tensile strength retention rate after thermal aging: 82% Example 3: The difference from Example 1 is that The ethylene propylene diene monomer rubber is changed to an ethylene propylene - polystyrene graft copolymer, still 8 parts; The silane-treated talc powder is replaced with silane-treated mica powder (D50 = 2 μm) with a dosage of 8 parts; The vacuum devolatilization temperature section is increased to 190 °C and the vacuum degree is -0.085 MPa.

[0027] The test results are as follows: Initial thermal decomposition temperature: 262 °C Tensile strength: 16.2 MPa Tensile strength retention rate after thermal aging: 81% There are no significant changes in electrical properties and corrosion resistance.

[0028] Example 4: The difference from Example 1 is that the plasticizer uses 48 parts of a high glass transition temperature (Tg>-20°C) polyester copolymer plasticizer; the amount of the thermal reaction compatibilizer added is increased to 3 parts; Using microwave-assisted heating and mixing, the mixing time is shortened to 4 minutes, and the discharge temperature is controlled not to exceed 190°C.

[0029] The test results are as follows: Thermal decomposition starting temperature: 267℃ Elongation at break: 240% Acid and alkali resistance is slightly improved, and the quality retention rate is 99% Comparative Example Comparative Example 1: In Comparative Example 1, no COPE elastomer was added, and the remaining proportions were the same as in Example 1.

[0030] The performance results are as follows: Elongation at break dropped to 180%; After heat aging, the strength retention rate dropped to 68%; The material showed obvious brittle cracks during the high-temperature bending test.

[0031] Comparative Example 2: In Comparative Example 2, the aromatic heterocyclic heat stabilizer was replaced with 3 parts of a common organotin stabilizer.

[0032] Performance results: The thermal decomposition starting temperature dropped to 245°C; the color darkened after thermal aging, the mechanical properties dropped significantly, and the strength retention rate was only 60%; the interfacial adhesion decreased due to HCl release.

[0033] Comparative Example 3: In Comparative Example 3, the magnetic controlled ultrasonic dispersion and vacuum devolatilization steps were not performed.

[0034] The performance results are as follows: the bubble rate in the particles increased significantly (>5%); the dielectric strength dropped to 16kV / mm; the volume resistivity dropped by 40% after aging, and the insulation grade degraded.

[0035] In order to compare the high temperature stability and flexibility of the polyvinyl chloride cable material particles of the embodiment and the comparative example, the following experiment was designed. The experimental steps are as follows: Preparation of experimental items: Samples were prepared according to the methods of the respective examples or comparative examples using high shear mixing, vacuum devolatilization, ultrasonic assistance, microwave melting and other processes to prepare polyvinyl chloride cable material particles. After granulation, they were pressed into tensile specimens (standard type III), sheets (thickness about 2 mm) and other experimental samples using hot pressing equipment.

[0036] Supporting instruments and equipment include high-temperature thermal aging chamber, universal material testing machine, thermogravimetric analyzer (TGA), repeated bending fatigue testing machine, electron microscope and standard light source light box, etc.

[0037] The experimental procedures are as follows: Thermal stability test: Place the molded sample in a high-temperature thermal aging oven at a constant temperature of 136°C for 168 hours. After aging, cool it to room temperature. Subsequently, use a universal material testing machine to measure the tensile strength, calculate the strength retention rate before and after aging, and use TGA to test the initial thermal decomposition temperature of the sample (i.e., the temperature at 5% mass loss).

[0038] Flexibility retention test: Cut the sheet samples before and after aging into standard strips respectively, and use a bending fatigue machine to repeatedly bend them with an inner diameter of 5 mm, and record the number of cycles when visible cracks first appear.

[0039] Meanwhile, use a universal material testing machine to measure the elongation at break, and calculate the elongation retention ratio before and after aging to evaluate the flexibility retention ability. Finally, select the fractured spline to observe the fracture morphology under SEM, and record the fracture structure and crack characteristics.

[0040] Experimental evaluation indicators: Initial thermal decomposition temperature: Reflects the heat resistance limit of the material, the higher the value, the better; Strength retention rate after thermal aging: The less the tensile strength decreases, the more stable the structure; Bending fatigue times: The higher it is, the better the flexibility retention after aging; Elongation at break retention rate: An important characterization of ductility and crack resistance performance; Crack morphology analysis: Judge the brittle fracture or plastic deformation mechanism, and provide a reference for structural stability.

[0041] The experimental data are shown in Table 1: Table 1 Experimental analysis: All examples showed excellent synergistic performance of high-temperature stability and flexibility. Especially in Example 4, with the combination of high-melting-point plasticizer + microwave-assisted processing, the performance is optimal; The performance of the comparative sample degraded significantly, indicating that the links such as COPE elastomer, heteroaromatic thermal stabilizer, vacuum devolatilization, and ultrasonic dispersion are the key control factors for performance synergy; The above results further prove that the present invention effectively solves the technical problem of "difficult to balance high-temperature stability and flexibility" of polyvinyl chloride cable material particles through a synergistic formulation and advanced processing means.

[0042] For the comparative experiment to measure the corrosion resistance and high-temperature stability of the polyvinyl chloride cable material particles in the examples and comparative examples, the following experiment is designed. The experimental procedures are as follows: Preparation of experimental articles: Samples of each experimental group were prepared into polyvinyl chloride cable material particles by combining the solvent method and the hot extrusion method according to the components in their respective examples or comparative examples, and then conventional particle granulation and molding were carried out. After preparation, aging simulation was carried out using a standard light source light box, and all samples were tested according to standard requirements.

[0043] The supporting instruments and equipment include an electron microscope (SEM), a corrosion test chamber, a thermal aging tester, a universal material testing machine, a spectrometer, etc.

[0044] The experimental steps are as follows: Corrosion performance test: Samples of each group were made into sheets according to the standard thickness and placed in a corrosion environment simulation chamber (simulating acid rain environment: pH = 4.5, 80% humidity, 50 °C ambient temperature) for long-term exposure (96 hours). The corrosion area and surface quality changes were measured every 24 hours (the change in surface metal ion content was measured using a spectrometer). After the exposure, the corrosion characteristics on the sample surface and the change in residual mechanical properties were observed.

[0045] Thermal aging and mechanical property test: The samples were subjected to thermal aging treatment at a set temperature of 120 °C for 72 hours. The thermal stability (mass loss curve) was measured by a thermogravimetric analyzer (TGA), and the tensile strength and elongation at break before and after thermal aging were measured using a universal material testing machine to evaluate the high-temperature stability and flexibility retention of the material.

[0046] Ultraviolet light aging test: The samples were placed in an ultraviolet light aging chamber for exposure to simulate a high-intensity ultraviolet environment (UVB band, 60 °C, 72 hours). After exposure, the surface cracks and color changes were observed, and the change in the surface microstructure was examined by an electron microscope (SEM) to further judge the ultraviolet tolerance of the material.

[0047] The experimental evaluation indexes are as follows: Change in corrosion area: Comparing the surface quality of the samples before and after exposure, the sample with a smaller corrosion area and less surface damage has better performance; Tensile strength: The higher the tensile strength after thermal aging, the better the thermal stability; Elongation at break: A high elongation at break indicates that the material has better flexibility and stronger adaptability; Thermal stability: The thermal stability of the material was analyzed by TGA. The higher the temperature and the less the mass loss, the better the high-temperature resistance performance; Surface changes after ultraviolet light aging: Fewer cracks and structural damages indicate that the material has strong ultraviolet anti-aging ability.

[0048] The experimental data are shown in Table 2: Table 2 Analysis of experimental conclusions, the performance advantages of the embodiments are as follows: Corrosion resistance: In the corrosion environment simulation test, Examples 5 to 8 showed significantly better corrosion resistance than the comparative examples, with significantly smaller corrosion areas and less change in surface quality. This indicates that optimizing the antioxidant and anti-ultraviolet components in the formulation effectively enhances the corrosion resistance of the material.

[0049] High-temperature stability: In the thermal aging test, the tensile strength retention rate and the initial temperature of thermal decomposition of the embodiments were both high, indicating strong stability and toughness retention ability in high-temperature environments. In particular, Example 8 showed the most excellent thermal stability and anti-aging ability.

[0050] Flexibility: All embodiments showed strong flexibility in terms of the elongation at break retention rate. In particular, Examples 6 and 8 had elongation at break retention rates close to or exceeding 90%, indicating that the optimized process effectively balanced flexibility and thermal stability.

[0051] UV aging resistance: The UV aging test results showed that the UV tolerance of the embodiments was significantly better than that of the comparative examples, with fewer surface cracks and no obvious metal ion migration.

[0052] Deficiencies of the comparative examples: Stronger corrosion: Comparative Examples 4 to 6 showed significantly worse performance than the embodiments in the corrosion test, with larger corrosion areas, obvious metal ion migration on the surface, and more serious surface damage.

[0053] Poor thermal stability: The thermal stability of the comparative examples was significantly lower than that of the embodiments, with a lower initial temperature of thermal decomposition, and obvious decreases in the strength retention rate and elongation retention rate, indicating that their high-temperature performance could not meet the actual application requirements.

[0054] Poor UV aging performance: After UV aging, the surfaces of the comparative examples had more cracks, obvious metal ion migration, and surface discoloration, indicating poor UV aging resistance.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention; those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed; the scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyvinyl chloride cable compound particle with corrosion resistance and high temperature resistance, characterized in that, It comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10 - 25 parts of high melting point block copolymer plasticizer; 5 - 10 parts of heat stabilizer with aromatic heterocyclic structure; 8 - 20 parts of multi-phase cross-linked elastomer blend material; 3 - 8 parts of highly efficient chelating flame retardant; 2 - 6 parts of fluorine-modified corrosion-resistant additive; 5 - 15 parts of silane-treated mineral filler.

2. The polyvinyl chloride cable material particles with corrosion resistance and high temperature resistance according to claim 1, characterized in that, The high melting point block copolymer plasticizer is made of block polyester-polyether copolymer and has a segment structure with a melting point not lower than 180 °C.

3. A polyvinyl chloride cable material particle resistant to corrosion and high temperature according to claim 1, characterized in that, The heat stabilizer with aromatic heterocyclic structure includes 2-benzothiazolopyridine compounds and bisphenol A derivatives, which are compounded in a weight ratio of 1:

1.

4. A polyvinyl chloride cable material particle resistant to corrosion and high temperature according to claim 1, characterized in that, The multi-phase cross-linked elastomer blend material is composed of ethylene propylene diene monomer rubber and peroxide-cross-linked polyether ester thermoplastic elastomer, and the cross-linking degree is 50% - 70%.

5. A polyvinyl chloride cable material particle with corrosion resistance and high temperature resistance according to claim 1, characterized in that, The fluorine-modified corrosion-resistant additive is a compound of perfluoroalkyl sulfonate and fluorosilane, and the mass ratio is 3:

2.

6. The polyvinyl chloride cable material particles with corrosion resistance and high temperature resistance according to claim 1, characterized in that, The silane-treated mineral filler is talc powder modified by silane coupling agent KH-570, and the particle size distribution is in the range of 1 - 3 μm, and the treatment temperature is controlled at 120 °C.

7. A processing process for polyvinyl chloride cable material particles with corrosion resistance and high temperature resistance, characterized in that The processing technology of a corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particle comprises the following steps: S1. Mix polyvinyl chloride resin with heat stabilizer with aromatic heterocyclic structure and high melting point block copolymer plasticizer in a mixer, control the temperature at 160 - 180 °C, and the mixing time is 5 - 10 minutes to obtain a mixture. S2. Add the multi-phase cross-linked elastomer blend material and the fluorine-modified corrosion-resistant additive to the mixture and continue mixing for 10 minutes. S3. Add the silane-treated mineral filler and the highly efficient chelating flame retardant to the mixture, carry out low-speed shear mixing, control the temperature at 140 - 150 °C, and the time is 3 - 5 minutes. S4. Extrude through a twin-screw extruder, cool and pelletize to obtain cable material particles.

8. A processing process of polyvinyl chloride cable material particles with corrosion resistance and high temperature resistance according to claim 7, characterized in that, In S2, a high-frequency magnetron ultrasonic field-assisted dispersion technology is adopted, the frequency is 20 - 40 kHz, and the action time is 3 - 6 minutes.

9. A processing technology for corrosion-resistant and high-temperature-resistant polyvinyl chloride cable material particles according to claim 7, characterized in that, In S3, vacuum devolatilization treatment is carried out to remove trace volatile monomers and unreacted substances in the system, the pressure is controlled at -0.08 ~ -0.1 MPa, and the time is 5 minutes.

10. A processing process of polyvinyl chloride cable material particles with corrosion resistance and high temperature resistance according to claim 7, characterized in that, The cable material particles are heat-treated at 160 °C for 2 hours.

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