High-temperature-resistant low-halogen high-flame-retardant polyolefin material as well as preparation method and application thereof

Abstract

The invention relates to a high-temperature-resistant low-halogen high-flame-retardant polyolefin material which comprises the following components in parts by mass: 20-25 parts of ethylene-vinyl acetate copolymer; 5-8 parts of ethylene propylene diene monomer; 8-12 parts of a polyethylene elastomer; 5 to 10 parts of grafting compatilizer; 40-53 parts of a flame retardant; 6.1 to 9.8 parts of an auxiliary agent; wherein the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 26%-28%. The invention also relates to a preparation method of the high-temperature-resistant low-halogen high-flame-retardant polyolefin material, which comprises the following steps: banburying the raw materials according to the proportion at 155-165 DEG C to obtain a molten material block; after double-step cone feeding is carried out, shearing and discharging are carried out in a double-screw extruder, and the shearing temperature ranges from 120 DEG C to 145 DEG C; extruding and granulating by a single screw, wherein the granulating temperature is 135-155 DEG C; and finally, carrying out air-cooling granulation on the granulated material, and then collecting, cooling and packaging the material to obtain the high-temperature-resistant low-halogen high-flame-retardant polyolefin material. The invention further relates to application of the high-temperature-resistant low-halogen high-flame-retardant polyolefin material in cables and wires.

Description

Technical Field

[0001] The present invention relates to the technical field of wire and cable materials, and in particular to a high-temperature resistant, low-halogen and highly flame-retardant polyolefin material and a preparation method and application thereof. Background Art

[0002] With the continuous development of the plastics industry, the power industry and the construction industry, as well as people's close attention to the safety of electricity, the application of wire and cable materials is becoming more and more extensive. The research and development of new wire and cable materials is the top priority of the current materials industry.

[0003] At present, the market requirements for polyolefin materials are mainly: first, low smoke and low halogen materials, with a temperature resistance of 150°C; second, flame retardant grade, which must pass UL1581 FT4 flame retardant; third, tensile strength and elongation at break must meet certain requirements; fourth, dielectric properties and flexibility after aging must also meet specifications. However, the wire and cable materials in the existing technology cannot meet the above requirements at the same time. Summary of the invention

[0004] The purpose of the present invention is to provide a high temperature resistant, low halogen and highly flame retardant polyolefin material and a preparation method and application thereof, which solves the problem that wire and cable materials in the prior art cannot simultaneously meet the requirements of high temperature resistant, low halogen and highly flame retardant properties.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a high temperature resistant, low halogen and highly flame retardant polyolefin material, comprising the following components in parts by weight:

[0007]

[0008]

[0009] The vinyl acetate content of the ethylene-vinyl acetate copolymer is 26% to 28%, the melt index of the ethylene-vinyl acetate copolymer is 3 to 6 g / 10 min; and the melt index of the polyethylene elastomer is 0.5 to 1.5 g / 10 min.

[0010] Furthermore, the grafted compatibilizer is a compatibilizer grafted with MLLDPE and maleic anhydride.

[0011] Furthermore, the flame retardant is a mixture of chemical magnesium hydroxide, decabromodiphenylethane and antimony trioxide, wherein the mass ratio of the chemical magnesium hydroxide, the decabromodiphenylethane and the antimony trioxide is (20-25):(15-21):(5-7).

[0012] Furthermore, the auxiliary agent includes at least one of a lubricant, an antioxidant, an antioxidant and a cross-linking agent.

[0013] Furthermore, the lubricant comprises an internal lubricant and an external lubricant, the internal lubricant is PE wax, the external lubricant is silicone masterbatch, and the lubricant is preferably a combination of 0.4-0.8 parts by mass of PE wax and 0.8-1.2 parts by mass of silicone masterbatch.

[0014] Furthermore, the antioxidant is a mixture of one or more selected from calcium zinc heat stabilizer, antioxidant MBZ and antioxidant 1035, and the antioxidant is preferably a combination of 1 to 1.5 parts of calcium zinc heat stabilizer, 1.5 to 2 parts of antioxidant MBZ and 0.5 to 0.8 parts of antioxidant 1035 in mass parts.

[0015] Furthermore, the antioxidant is a mixture of one or more selected from antioxidant 1010, anti-copper agent 1024 and anti-copper agent 697, and the antioxidant is preferably a combination of 0.3 to 0.5 parts by weight of antioxidant 1010, 0.3 to 0.5 parts by weight of anti-copper agent 1024 and 0.3 to 0.5 parts by weight of anti-copper agent 697.

[0016] Furthermore, the cross-linking agent is TAIC, and the cross-linking agent is preferably 1 to 2 parts by mass of TAIC.

[0017] The second aspect of the present invention provides a method for preparing a high temperature resistant, low halogen and highly flame retardant polyolefin material, comprising the following steps:

[0018] S1: Put the above raw materials into a mixer according to the proportion and mix them to obtain a molten material block. The mixing temperature is 155-165°C;

[0019] S2: After the molten material block is subjected to double-stage cone feeding, it is sheared and discharged in a twin-screw extruder at a shear temperature of 120-145° C.;

[0020] S3: extruding the sheared material in step S2 into granules through a single screw, with the granulation temperature being 135-155° C.;

[0021] S4: air-cooling and pelletizing the granulated material in step S3, followed by collecting, cooling and packaging the material to obtain the high temperature resistant, low halogen and highly flame retardant polyolefin material.

[0022] The third aspect of the present invention provides an application of a high temperature resistant, low halogen and highly flame retardant polyolefin material, wherein the high temperature resistant, low halogen and highly flame retardant polyolefin material can be applied to cables and wires.

[0023] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0024] The present invention provides a high temperature resistant, low halogen and highly flame retardant polyolefin material, comprising the following components by mass: 20 to 25 parts of ethylene-vinyl acetate copolymer; 5 to 8 parts of ethylene propylene diene monomer; 8 to 12 parts of polyethylene elastomer; 5 to 10 parts of grafting compatibilizer; 40 to 53 parts of flame retardant; 6.1 to 9.8 parts of auxiliary agent; wherein the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 26% to 28%; such ethylene-vinyl acetate copolymer has strong processability and good radiation cross-linking performance; ethylene propylene diene monomer has good compatibility with the above copolymer; the use of polyolefin elastomer greatly improves the mechanical and physical properties of the material, and the use of flame retardant and auxiliary agent makes the prepared high temperature resistant, low halogen and highly flame retardant polyolefin material have excellent performance. The polyolefin material prepared in the present invention withstands high temperature pressure at 150°C and 2500V, and passes the UL1581 VW-1 flame retardant test. DETAILED DESCRIPTION

[0025] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0026] The high-temperature resistant, low-halogen and highly flame-retardant polyolefin material of the present invention comprises the following components in parts by weight: 20 to 25 parts of ethylene-vinyl acetate copolymer; 5 to 8 parts of ethylene propylene diene rubber; 8 to 12 parts of polyethylene elastomer; 5 to 10 parts of grafting compatibilizer; 40 to 53 parts of flame retardant; and 6.1 to 9.8 parts of auxiliary agent.

[0027] The ethylene-vinyl acetate copolymer selected in the embodiment of the present invention has a VA content of 26% to 28% and a melt index of 3 to 6 g / 10 min, such as Formosa Plastics' 7470M, Sulbond's 6020M, Levima's 00428 and Exxon's 00328. This type of EVA has good mechanical and physical properties and good fluidity, and has good radiation cross-linking properties, and has strong processability in wire and cable materials.

[0028] The EPDM rubber used in the present invention has an ethylene content of ≥65% and a Mooney viscosity of ≤30, such as Dow's 4725P, Mitsui's EPT3012P, Lanxess's 2070P, etc. This type of EPDM rubber has good compatibility with the aforementioned ethylene resin, and has excellent mechanical properties and a good degree of radiation crosslinking, and does not affect the processing and use of the material.

[0029] The polyethylene elastomer used in the present invention is a 4C high tensile strength material with a melt index of 0.5-1.5 g / 10 min, such as DF810 from Mitsui and 7270 from DOW. Such materials have good mechanical and physical properties and moderate fluidity.

[0030] The grafted compatibilizer in the present invention is a compatibilizer grafted with MLLDPE and maleic anhydride. Such a material has excellent compatibility and mechanical and physical properties, can increase the tensile strength and filling dispersibility of the material, and also has good extrusion processing performance.

[0031] As for the flame retardant, the flame retardant selected in the embodiment of the present invention is a composition of chemical magnesium hydroxide, decabromodiphenylethane and antimony trioxide. Among them, the chemical magnesium hydroxide is selected as an imported material, such as S-6 from Japan's Kamishima, H5 from Albemarle, etc. Such materials have good flame retardant properties as filling flame retardants, and have good dispersion properties in the material, which is beneficial to improving the extrusion processing performance of the material. Decabromodiphenylethane has environmental protection performance, has excellent flame retardant properties in resin materials, and does not affect the extrusion processing and use of the material. Antimony trioxide is selected with a purity of 99.8%, and the compound decabromodiphenylethane has excellent flame retardant self-extinguishing properties, which can improve the flame retardant properties of the material.

[0032] In addition to the above-mentioned preparations, a certain amount of auxiliary agents are added in the present invention for material compounding. Specifically, the auxiliary agents include at least one of lubricants, antioxidants, antioxidants and cross-linking agents.

[0033] In the embodiment of the present invention, an internal lubricant and an external lubricant are compounded and used together. PE wax (such as Honeywell's AC-6A) is selected for internal lubrication, and silicone masterbatch is selected for external lubricant. Such mixed lubricants have good surface lubrication effects, which are helpful to increase the surface finish of the material and avoid over-temperature decomposition of the material during processing. The antioxidant is a mixture of one or more of calcium zinc heat stabilizer, antioxidant MBZ and antioxidant 1035. The role of calcium zinc heat stabilizer is to prevent the embrittlement of the material under high temperature conditions, and the role of antioxidant MBZ and antioxidant 1035 is to improve the stability of the material under high temperature conditions and reduce the oxidation effect of the material under high temperature conditions. The antioxidant is a mixture of one or more of antioxidant 1010, anti-copper agent 1024 and anti-copper agent 697. The role of antioxidant 1010 is to reduce the oxidation effect of the material under high temperature conditions, and the role of anti-copper agent 1024 and anti-copper agent 697 is to reduce the embrittlement effect of copper ions on the material when the material contacts the copper core. The crosslinking agent used is TAIC. Due to the high crosslinking effective content of TAIC, it can increase the crosslinking degree of the material, thereby promoting the flame retardancy, high temperature resistance and tensile strength of the material.

[0034] The present invention also provides a method for preparing the high temperature resistant, low halogen and highly flame retardant polyolefin material as described above, comprising the following steps:

[0035] S1: Put the raw materials into a mixer according to the proportion and mix them to obtain a molten material block. The mixing temperature is 155-165°C;

[0036] S2: After the molten material block is subjected to double-stage cone feeding, it is sheared and discharged in a twin-screw extruder at a shear temperature of 120-145° C.;

[0037] S3: extruding the sheared material in step S2 into granules through a single screw, with the granulation temperature being 135-155° C.;

[0038] S4: air-cooling and pelletizing the granulated material in step S3, followed by collecting, cooling and packaging the material to obtain the high temperature resistant, low halogen and highly flame retardant polyolefin material.

[0039] Certain embodiments are selected below to further describe the present invention.

[0040] Examples 1 to 3 and Comparative Examples 1 to 16 respectively provide a high temperature resistant, low halogen and highly flame retardant polyolefin material. The amounts of components in each example and comparative example are shown in Table 1.

[0041] Note: In Examples 1 to 3, the ethylene-vinyl acetate copolymer is 7470M produced by Formosa Plastics (vinyl acetate content is 26%, melt index is 7.5 g / min), the EPDM is 4725P produced by Dow Chemical (ethylene content is 70%, Mooney viscosity is 25), and the polyethylene elastomer is DF810 produced by Mitsui (melt index is 1.2 g / min).

[0042] The grafted compatibilizer used is MLLDPE3518 and maleic anhydride grafted compatibilizer, and its brand is ExxonMobil's 3518 grafted compatibilizer; the chemical magnesium hydroxide uses Japan's Kamishima S-6, the decabromodiphenylethane uses Tianyi's decabromodiphenylethane, and the antimony trioxide uses 99.8% antimony trioxide from Xiangmeng.

[0043] The lubricant used is MaiTai's silicone masterbatch with 50% PE carrier and Honeywell's PE wax AC-6A (wherein the mass ratio of silicone masterbatch to PE wax AC-6A is 2-3:1-2), and the antioxidants used are Aidico calcium zinc stabilizer 288G, Shanghai Dirui's antioxidant MBZ, Shanghai Dirui's antioxidant 1035, extremely easy antioxidant 1010, extremely easy anti-copper agent 1024 and 697 (wherein the mass ratio of stabilizer 288G, antioxidant MBZ, antioxidant 1035, antioxidant 1010, anti-copper agent 1024 and anti-copper agent 697 is 10-15:15-20:5-8:3-5:3-5:3-5).

[0044] Table 1 Composition of high temperature resistant, low halogen and highly flame retardant polyolefin materials in Examples 1 to 3 and Comparative Examples 1 to 16

[0045]

[0046]

[0047]

[0048] Note: The ethylene-vinyl acetate copolymer used in Comparative Example 1 has a vinyl acetate content of 18%, a melt index of 3.5 g / min, and a brand name of 18J3 from Yanshan Petrochemical; the ethylene-vinyl acetate copolymer used in Comparative Example 2 has a vinyl acetate content of 33%, a melt index of 30 g / min, and a brand name of 150VA from Mitsui; the ethylene-vinyl acetate copolymer used in Comparative Example 3 has a vinyl acetate content of 28%, a melt index of 20 g / min, and a brand name of SV1055 from TPI of Thailand.

[0049] The Mooney viscosity of the EPDM rubber used in Comparative Example 4 is 40, the ethylene content is 65%, and its brand is Mitsui's EPT1045; the Mooney viscosity of the EPDM rubber used in Comparative Example 5 is 25, the ethylene content is 55%, and its brand is Mitsui's EPT4021.

[0050] The polyethylene elastomer used in Comparative Example 6 has a tensile strength of 8C and a melt index of 1.5 g / min, and its brand is DOW 8150; the polyethylene elastomer used in Comparative Example 7 has a tensile strength of 4C and a melt index of 3.5 g / min, and its brand is Mitsui's DF710; the grafting compatibilizer used in Comparative Example 8 is LDPE grafting, and its brand is Yanshan Petrochemical 7042; the grafting compatibilizer used in Comparative Example 9 is POE grafting, and its brand is DOW 8150.

[0051] The performance of the high temperature resistant, low halogen and highly flame retardant polyolefin materials in Examples 1 to 3 and Comparative Examples 1 to 16 was tested, and the test results are shown in Table 2.

[0052] Table 2 Performance test table of high temperature resistant, low halogen and highly flame retardant polyolefin materials in Examples 1 to 3 and Comparative Examples 1 to 16

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] Note: When testing tensile strength, it is necessary to pass the UL1581 standard, and the required value is ≥13.8Mpa; when testing elongation at break, it is necessary to pass the UL1581 standard, and the required value is ≥300%; when testing flame retardancy, it is necessary to pass the UL1581, VW-1 flame retardancy test; when testing aging performance, the insulated wire tube, UL ventilation aging box, 180℃*168h, test speed 500mm / s, the strength retention rate is required to be ≥80%, and the elongation retention rate is ≥80%.

[0059] When testing the dielectric properties after aging①, UL758.29 with copper core cable, UL ventilated aging box, 180℃*168h, after aging, place it at room temperature for 16h, apply 2500V voltage power supply on both sides of the line end for 1min during the test, and require that there is no breakdown on the surface of the wire; when testing the dielectric flexibility after aging, with copper core cable, UL ventilated aging box, 180℃*168h, after aging, place it at room temperature for 16h, wrap 6 turns on a 2.8mm winding rod, apply 2500V voltage power supply on both sides of the line end for 1min during the test, and require that there is no breakdown on the surface of the wire.

[0060] When testing the dielectric performance after aging②, UL758.31 copper core cable is immersed in water for 24 hours (normal temperature). During the test, 2500V voltage power supply is applied on both sides of the line end for 1 minute, and the surface of the wire is required to have no breakdown; when testing the dielectric performance after aging③, IL758.30 copper core cable is used in UL ventilated aging box, 180℃*168h. After aging, it is placed at room temperature for 16 hours, and then the test line is placed in a 150℃ oven. During the test, 2500V voltage power supply is applied on both sides of the line end for 1 minute, and the surface of the wire is required to have no breakdown.

[0061] It can be concluded from the data changes in Table 2 that the appropriate material ratios in Examples 1 to 3 meet the test performance of the materials, and the performance of the polyolefin material provided in Example 1 is the best.

[0062] Comparative Examples 1-9: The influence of ethylene-vinyl acetate copolymer materials on mechanical and physical properties and residual rate of performance after aging; EPDM affects the extrusion surface, mechanical and physical properties and aging properties of the material; polyethylene elastomer has a greater influence on the aging properties of the material; the grafting compatibilizer mainly affects the mechanical and aging properties of the material. Comparative Examples 10-14: Regarding the influence of flame retardant materials, magnesium hydroxide must use chemical magnesium hydroxide, and quantitative addition can ensure the flame retardant and mechanical and physical properties of the material; decabromodiphenylethane has a great influence on the flame retardant and physical properties of the material, and the appropriate addition amount can ensure the qualified performance of the material. Comparative Examples 15-16: Regarding the influence of auxiliary materials, antioxidants have a great influence on the aging performance of the material, and sufficient antioxidants can ensure the aging performance of the material; lubricants have an influence on the processing surface of the material; cross-linking agents have an influence on the aging performance of the material.

[0063] In summary, in the present invention, ethylene-vinyl acetate copolymer with a specific VA content is selected, combined with EPDM rubber with good compatibility, and a certain amount of flame retardant and additives are added under the support of MLLDPE and maleic anhydride grafted compatibilizer, thereby preparing a high temperature resistant, low halogen and highly flame retardant polyolefin material with excellent anti-aging and oxidation properties and mechanical and physical properties.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature resistant, low halogen and highly flame retardant polyolefin material, characterized in that: It is composed of the following components in parts by mass: 20-25 parts of ethylene-vinyl acetate copolymer; 5~8 parts of EPDM; 8-12 parts of polyethylene elastomer; 5-10 parts of grafting compatibilizer; Flame retardant 40~53 parts; Additives 6.1~9.8 parts; The vinyl acetate content of the ethylene-vinyl acetate copolymer is 26% to 28%, the melt index of the ethylene-vinyl acetate copolymer is 3 to 6 g / 10 min; and the melt index of the polyethylene elastomer is 0.5 to 1.5 g / 10 min.

2. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 1, characterized in that: The grafted compatibilizer is a compatibilizer grafted with MLLDPE and maleic anhydride.

3. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 1, characterized in that: The flame retardant is a mixture of chemically produced magnesium hydroxide, decabromodiphenylethane and antimony trioxide, wherein the mass ratio of the chemically produced magnesium hydroxide, the decabromodiphenylethane and the antimony trioxide is (20-25): (15-21): (5-7).

4. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 1, characterized in that: The auxiliary agent includes at least one of a lubricant, an antioxidant, an antioxidant and a cross-linking agent.

5. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 4, characterized in that: The lubricant comprises an internal lubricant and an external lubricant, the internal lubricant is PE wax, the external lubricant is silicone masterbatch, and the lubricant is preferably a combination of 0.4-0.8 parts by mass of PE wax and 0.8-1.2 parts by mass of silicone masterbatch.

6. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 4, characterized in that: The antioxidant is a mixture of one or more selected from calcium zinc heat stabilizer, antioxidant MBZ and antioxidant 1035. The antioxidant is preferably a combination of 1-1.5 parts of calcium zinc heat stabilizer, 1.5-2 parts of antioxidant MBZ and 0.5-0.8 parts of antioxidant 1035 in mass parts.

7. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 4, characterized in that: The antioxidant is a mixture of one or more selected from antioxidant 1010, anti-copper agent 1024 and anti-copper agent 697. The antioxidant is preferably a combination of 0.3-0.5 parts by weight of antioxidant 1010, 0.3-0.5 parts by weight of anti-copper agent 1024 and 0.3-0.5 parts by weight of anti-copper agent 697.

8. The high temperature resistant, low halogen and highly flame retardant polyolefin material according to claim 4, characterized in that: The cross-linking agent is TAIC, and the cross-linking agent is preferably 1 to 2 parts by weight of TAIC.

9. A method for preparing a high temperature resistant, low halogen and highly flame retardant polyolefin material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Put the raw materials in claims 1-8 into an internal mixer in proportion and mix them to obtain a molten material block. The mixing temperature is 155-165° C.; S2: After the molten material block is subjected to double-stage cone feeding, it is sheared and discharged in a twin-screw extruder at a shear temperature of 120-145° C.; S3: extruding the sheared material in step S2 into granules through a single screw extruder at a granulation temperature of 135-155° C.; S4: air-cooling and pelletizing the granulated material in step S3, followed by collecting, cooling and packaging the material to obtain the high temperature resistant, low halogen and highly flame retardant polyolefin material.

10. Use of the high temperature resistant, low halogen and highly flame retardant polyolefin material according to any one of claims 1 to 8 in cables and wires.

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