B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with d0-grade combustion drippings and preparation method of B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material

Abstract

The invention provides a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 grade and a preparation method thereof. The B1-grade low-smoke halogen-free flame-retardant cable material is prepared from the following components in parts by weight: 15 to 25 parts of ethylene-vinyl acetate copolymer, 5 to 10 parts of linear low-density polyethylene, 5 to 10 parts of ethylene-octylene copolymer, 1 to 6 parts of maleic anhydride grafting agent, 1 to 2 parts of color master batch, 50 to 70 parts of flame retardant, 1 to 6 parts of ceramic forming aid, 0.5 to 1.5 parts of charring agent, 0.5 to 2 parts of lubricant and 0.2 to 1 part of antioxidant. The B1-grade low-smoke halogen-free flame-retardant cable material does not melt and drop in the combustion process, is good in carbon forming effect, non-toxic, low-smoke and excellent in mechanical property and processing extrusion performance, and is particularly suitable for the fields of the building industry, the communication industry, the electric power industry and the like. The method is high in process operability and easy for industrial large-scale production, and has good economic benefits and wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant cable technology, and in particular to a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method. Background Technology

[0002] In modern construction and industrial sectors, the safety requirements for cable materials are becoming increasingly stringent, especially in terms of fire safety. Traditional cable materials may release toxic fumes and corrosive gases in the event of a fire. Furthermore, traditional cable materials are prone to large-scale dripping during combustion, which not only increases the risk of personal injury and death in a fire but also threatens property safety. Therefore, developing a low-smoke, non-toxic cable material with a drip rate of d0 has become particularly important. The market demand for low-smoke, halogen-free, flame-retardant cables is growing, especially in public utilities, transportation, construction, and industrial sectors, where higher requirements are placed on the safety and environmental performance of cables.

[0003] Patent application CN 115710396 A discloses a B1-grade, drip-free, low-smoke, halogen-free polyolefin cable material. The main mechanism involves the esterification reaction between inorganic acids released from an acid source and polyols. The resulting water vapor and non-combustible gases released from a gas source cause the molten system to expand and foam. Simultaneously, the polyol and esters dehydrate and carbonize, forming inorganic matter and carbon residues, further promoting system expansion and foaming. Near the completion of the reaction, the system gels and solidifies. This invention effectively suppresses dripping during combustion, thus improving cable safety to some extent. However, the formulation introduces melamine, which may release harmful ammonia gas during combustion, potentially having adverse effects on the environment and human health. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method. This material replaces traditional halogen-containing materials with environmentally friendly flame retardants, which not only releases very little smoke and toxic gases during combustion, but also has excellent anti-dripping effect and good mechanical properties. At the same time, it simplifies the production process, reduces costs, and ensures the long-term stability and reliability of the material, making it suitable for various high-end cable manufacturing needs.

[0005] The technical solution of this invention is:

[0006] The first aspect of this invention provides a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0, comprising the following raw materials by weight:

[0007]

[0008] The second aspect of this invention provides a method for preparing a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0. The preparation method includes: mixing ethylene-vinyl acetate copolymer, linear low-density polyethylene, ethylene-octene copolymer, maleic anhydride grafting agent, color masterbatch, and lubricant evenly according to the specified ratio; finally adding flame retardant, ceramic-forming aid, charring agent, and antioxidant; and then mixing, extruding, pelletizing, and drying to obtain a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0.

[0009] The third aspect of this invention provides the application of the B1 grade low-smoke halogen-free flame-retardant polyolefin sheathing material with a combustion dripping grade of d0 as described in this invention in the field of cables.

[0010] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0011] The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material of the present invention, with a combustion dripping grade of d0, has good comprehensive performance, excellent mechanical properties, good processing flow properties and heat aging resistance, and can meet the B1-grade combustion index and dripping grade requirements. It is particularly suitable for large industrial equipment, railway signal cables and other fields. Detailed Implementation

[0012] The following details the implementation of the B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method provided by the present invention.

[0013] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0014] Through extensive research and exploration, the inventors of this invention provide a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method. The method utilizes a blend of ethylene-vinyl acetate copolymer and ethylene-octene copolymer resins as the base material to improve the material's flexibility and processability. Simultaneously, linear low-density polyethylene is introduced to enhance the material's crack resistance. Maleic anhydride grafting agents are used to connect inorganic and organic materials. Combined with flame retardants, ceramic-forming agents, charring agents, lubricants, and antioxidants, the prepared B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 exhibits excellent comprehensive performance and good molding and processing properties. Based on this, this application was completed.

[0015] [B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping rating of d0]

[0016] This invention provides a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0, comprising ethylene-vinyl acetate copolymer, linear low-density polyethylene, ethylene-octene copolymer, maleic anhydride grafting agent, color masterbatch, lubricant, flame retardant, ceramicizing agent, charring agent, and antioxidant.

[0017] In some embodiments of the present invention, the ethylene-vinyl acetate copolymer is 15-25 parts by weight, optionally 15-20 parts, 20-25 parts, 15-18 parts, 18-20 parts, 20-22 parts, 22-25 parts, etc. For example, the ethylene-vinyl acetate copolymer is 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts by weight, etc. The ethylene-vinyl acetate copolymer is a mixture of two copolymers with different vinyl acetate (VA) contents, and the VA content of both different vinyl acetates is greater than 25%. Optionally, the ethylene-vinyl acetate copolymer is two of the following: BASF 6110M, Taipoly 33002, and DowDuPont 220W. Preferably, the mixture of BASF 6110M and 33002 is used, and the ratio of the two can be 15:5 to 19:1, for example, 15:5, 16:4, 17:3, 18:2, or 19:1.

[0018] In some embodiments of the present invention, the linear low-density polyethylene is 5-10 parts by weight, optionally 5-8 parts, 8-10 parts, 5-6 parts, 6-7 parts, 7-8 parts, 8-9 parts, or 9-10 parts, etc. For example, the linear low-density polyethylene is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts by weight, etc. Optionally, the density of the linear low-density polyethylene is 0.915-0.945 g / cm³. 3Preferably, the linear low-density polyethylene is one or more of the following: Borealis bimodal polyethylene and Saudi 218WJ.

[0019] In some embodiments of the present invention, the ethylene-octene copolymer is 5-10 parts by weight, optionally 5-8 parts, 8-10 parts, 5-6 parts, 6-7 parts, 7-8 parts, 8-9 parts, or 9-10 parts, etc. For example, the ethylene-octene copolymer is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts by weight, etc. The density of the ethylene-octene copolymer is 0.85-0.95 g / cm³. 3 The melt flow index is 0.5-2 g / 10 min, for example, the melt flow index can be 0.5-1 g / 10 min, 1-2 g / 10 min, 1-1.5 g / 10 min, or 1.5-2 g / 10 min. Preferably, the ethylene-octene copolymer is one or more of DowDuPont's 8100 and Exxon's 3980FL.

[0020] In some embodiments of the present invention, the maleic anhydride grafting aid is 1-6 parts by weight, optionally 1-3 parts, 3-6 parts, 1-5 parts, 5-6 parts, 1-2 parts, 2-4 parts, 4-6 parts, etc. For example, the maleic anhydride grafting aid is 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts by weight, etc. Optionally, the grafting rate of the maleic anhydride grafting aid is greater than 0.8%. Preferably, the maleic anhydride grafting aid is one or more of Y5102 from Yunfeiyang Plastics and MC509 from Nengzhiguang.

[0021] In some embodiments of the present invention, the color masterbatch is 1-2 parts by weight, optionally 1-1.4 parts, 1.4-2 parts, 1-1.6 parts, or 1.6-2 parts. For example, the color masterbatch may be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2 parts by weight. Optionally, the carbon black content in the color masterbatch shall not be less than 45%, and the dispersion grade shall not be less than grade 2. Preferably, the color masterbatch is one or more of Cabot's 2762 and 2718.

[0022] In some embodiments of the present invention, the flame retardant is present in parts by weight of 50-70, optionally 50-60, 60-70, 50-55, 55-60, 60-65, 65-70, etc. For example, the flame retardant may be present in parts by weight of 50, 55, 60, 65, 70, etc. Optionally, the flame retardant is selected from one or at least two combinations of aluminum hydroxide, magnesium hydroxide, and phosphosilicon compounds. For example, the aluminum hydroxide may have a particle size D50 of less than 3 micrometers.

[0023] In some embodiments of the present invention, the ceramic-forming aid is 1-6 parts by weight, optionally 1-3 parts, 3-6 parts, 1-5 parts, 5-6 parts, 1-2 parts, 2-4 parts, 4-6 parts, etc. For example, the ceramic-forming aid may be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts by weight, etc. Optionally, the particle size of the ceramic-forming aid may be 5-10 micrometers, more specifically 5-7 micrometers, 7-10 micrometers, etc. Optionally, the ceramic-forming aid is one or more of wollastonite and ceramic powder. For example, it may be wollastonite from Fangli Chemical.

[0024] In some embodiments of the present invention, the charring agent is 0.5-1.5 parts by weight, optionally 0.5-1 part, 1-1.5 parts, 0.5-1.5 parts, etc. For example, the charring agent is 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, etc. Optionally, the charring agent is one or a combination of two of XY101 and CFA.

[0025] In some embodiments of the present invention, the lubricant is 1-2 parts, optionally 1-1.4 parts, 1.4-2 parts, 1-1.6 parts, or 1.6-2 parts by weight. For example, the lubricant may be 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2 parts by weight. Optionally, the lubricant is one or a combination of two of the following: imported polyethylene wax with a molecular weight greater than 50,000 or silicone masterbatch with a siloxane content of not less than 50%. For example, the lubricant may be one or more of SR-208 and SR-500 from Guangzhou Yinyuan.

[0026] In some embodiments of the present invention, the antioxidant is present in a weight ratio of 0.2-1 parts, optionally 0.2-0.6 parts, 0.6-1 parts, 0.2-0.3 parts, 0.3-1 parts, 0.2-0.4 parts, 0.4-0.6 parts, 0.6-0.8 parts, 0.8-1 parts, etc. For example, the antioxidant may be present in weight ratios of 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, etc. Optionally, the antioxidant is a combination of a primary antioxidant and a secondary antioxidant. Preferably, the primary antioxidant is selected from hindered phenols 1010 or 1222. The secondary antioxidant is selected from thioesters DSTP and DLTP. The weight ratio of the primary and secondary antioxidants can be 1:1 to 3:1, optionally 1:1 to 2:1 or 2:1 to 3:1, etc. For example, the ratios could be 1:1, 2:1, or 3:1.

[0027] Preparation method of B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0

[0028] This invention also provides a method for preparing a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0. The preparation method includes: mixing ethylene-vinyl acetate copolymer, linear low-density polyethylene, ethylene-octene copolymer, maleic anhydride grafting agent, color masterbatch, and lubricant evenly according to the specified ratio; finally adding flame retardant, ceramic-forming aid, charring agent, and antioxidant; and then mixing, extruding, pelletizing, and drying to obtain a B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0.

[0029] In the preparation method provided by the present invention, the mixing temperature is 150-175°C, and can be selected as 150-165°C or 165-175°C.

[0030] In the preparation method provided by the present invention, the drying temperature is 60-90℃, and can be selected as 60-70℃, 70-80℃ or 80-90℃.

[0031]

application

[0032] The present invention also provides the application of the B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 as described in the present invention in the fields of large industrial equipment and railway signal cables.

[0033] The beneficial effects of the present invention will be further illustrated below with reference to the embodiments.

[0034] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention is further described in detail below with reference to embodiments. However, it should be understood that the embodiments of this invention are merely for illustrative purposes and not for limiting the invention, and the embodiments are not limited to those given in the specification. Unless otherwise specified, specific experimental or operational conditions in the embodiments were prepared under conventional conditions or according to the conditions recommended by the material supplier.

[0035] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0036] In the following embodiments, unless otherwise specified, all the raw materials of the present invention are commercially available or prepared according to conventional methods in the art.

[0037] Example 1

[0038] This embodiment discloses a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method, characterized in that it comprises the following raw materials in parts by weight:

[0039] 15 parts of ethylene-vinyl acetate copolymer;

[0040] Six parts of linear low-density polyethylene;

[0041] 6 parts of ethylene-octene copolymer;

[0042] 5 parts of maleic anhydride grafting agent;

[0043] 1.6 parts color masterbatch;

[0044] 70 parts flame retardant;

[0045] Five parts of porcelain-forming additive;

[0046] One part of charring agent;

[0047] 1.6 parts lubricant;

[0048] Antioxidant 0.3 parts.

[0049] The ethylene-vinyl acetate copolymer is a blend of BASF Yangzi's 6110M and Taipoly's 33002 in a ratio of 15:5. 6110M contains 26.5% VA, and 33002 contains 33% VA. The linear low-density polyethylene is Borealis bimodal polyethylene with a density of 0.936 g / cm³. 3 The ethylene-octene copolymer is DowDuPont's 8100, with a density of 0.868 g / cm³. 3 The melt index is 1g / 10min; the maleic anhydride grafting agent is Y5102 from Yunfeiyang Plastics, with a grafting rate greater than 0.8%, for example, a grafting rate of 1%; the color masterbatch is Cabot's 2762, with a carbon black content of 50%; the flame retardant is AH-1 from Aluminum Corporation of China, whose composition is aluminum hydroxide, and its particle size D50 is less than 3 micrometers; the ceramic-forming aid is wollastonite from Fangli Chemical, with a particle size of less than 7 micrometers; the charring agent is XY101 from Xingyuan Chemical; the lubricant is SR-208 from Guangzhou Yinyuan, with linear low-density polyethylene as the carrier and a siloxane content of 50%; the antioxidant is a compound of primary antioxidant and secondary antioxidant, with the primary antioxidant being hindered phenol 1010 and the secondary antioxidant being thioester DLTP, and the weight ratio of the primary and secondary antioxidants being 2:1.

[0050] The following is an embodiment of a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 and its preparation method:

[0051] According to the above formula, ethylene-vinyl acetate copolymer, linear low-density polyethylene, ethylene-octene copolymer, maleic anhydride grafting agent, and color masterbatch are added to the high-speed mixer and run at low speed for two minutes. Then, flame retardant, ceramic-forming aid, charring agent, lubricant, and antioxidant are added and mixed at high speed in the mixer for 3 minutes. After being fully mixed and homogeneous, the mixture is further extruded, cooled, granulated, dried, sieved, and packaged.

[0052] Example 2

[0053] The difference between this embodiment and Embodiment 1 is that the ethylene-vinyl acetate copolymer 6110M and ethylene-vinyl acetate copolymer 33002 are used, wherein the content of EVA6110M is increased by 3 parts and the content of EVA33002 is decreased by 3 parts, while the rest are the same as in Embodiment 1.

[0054] The preparation method in this embodiment is the same as that in Example 1. Unless otherwise specified, the preparation methods in subsequent embodiments and comparative examples are the same as those in Example 1.

[0055] Example 3

[0056] The difference between this embodiment and Example 1 is that the linear low-density polyethylene is reduced by one part, and the ethylene-octene copolymer is increased by one part; otherwise, they are the same as in Example 1.

[0057] Example 4

[0058] The difference between this embodiment and Example 1 is that the amount of maleic anhydride grafting agent is reduced by 2 parts, and the amount of EVA6110M is increased by 2 parts, while the rest is the same as in Example 1.

[0059] Example 5

[0060] The difference between this embodiment and Example 1 is that the amount of maleic anhydride grafting agent is reduced by 2 parts, and the amount of EVA33002 is increased by 2 parts, while the rest is the same as in Example 1.

[0061] Example 6

[0062] The difference between this embodiment and Embodiment 1 is that the number of parts of linear low-density polyethylene is reduced by 2 parts, and the number of parts of maleic anhydride grafting agent is increased by 2 parts, while the rest are the same as in Embodiment 1.

[0063] Example 7

[0064] The difference between this embodiment and Embodiment 1 is that the number of flame retardants is reduced by 3 parts, and the number of ceramic-forming additives is increased by 3 parts; all other aspects are the same as in Embodiment 1.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that the ethylene-vinyl acetate copolymer 6110M and ethylene-vinyl acetate copolymer 33002 are used, wherein the amount of EVA 6110M is increased to 20 parts and the amount of EVA 33002 is reduced to 0 parts, while the rest are the same as in Example 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that the ethylene-vinyl acetate copolymer 6110M and maleic anhydride grafting agent are used, wherein the amount of maleic anhydride grafting agent is reduced to 0 parts, and the reduced amount of maleic anhydride grafting agent is increased on EVA6110M, while the rest are the same as in Example 1.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is that the amount of lubricant is reduced by 0.3 parts, while everything else is the same as in Example 1.

[0071] The performance of a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 prepared in Examples 1-8 and Comparative Examples 1-3 was tested, and the test results are shown in Table 1.

[0072] The testing standards are as follows:

[0073] The tensile strength test standard is in accordance with GB / T 1040, the elongation at break test standard is in accordance with GB / T 1040, the density test standard is in accordance with GB / T 1033, the volume resistivity test standard is in accordance with GB / T 1410, and the thermal aging test standard is in accordance with GB / T2951.21.

[0074] Table 1: Performance Comparison Analysis Table

[0075]

[0076] The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 prepared in the above examples and comparative examples was used for cable extrusion. The model and specification were WDZB1-YJY-0.6 / 1kv-4×35+1×16. The B1-grade combustion test was carried out according to GB / T 31248.

[0077] Table 2: Performance Comparison Analysis Table

[0078]

[0079]

[0080] As can be seen from Tables 1 and 2, the B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to the present invention has good comprehensive performance, excellent mechanical properties, good heat aging resistance, and can meet the B1 grade combustion index and dripping grade requirements. It is particularly suitable for large industrial equipment, railway signal cables and other fields.

[0081] Example 1 demonstrates that by selecting the right resin, rationally combining various additives, and using appropriate proportions, all performance indicators are met.

[0082] The difference between Example 2 and Example 1 is that the ethylene-vinyl acetate copolymer used is a blend of 6110M and 33002, wherein the content of EVA 6110M is increased by 3 parts and the content of EVA 33002 is decreased by 3 parts. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0083] The difference between Example 3 and Example 1 is that the linear low-density polyethylene is reduced by one part and the ethylene-octene copolymer is increased by one part. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0084] The difference between Example 4 and Example 1 is that the amount of maleic anhydride grafting agent is reduced by 2 parts, and the amount of ethylene-vinyl acetate copolymer 6110M used is increased by 2 parts. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0085] The difference between Example 5 and Example 1 is that the amount of maleic anhydride grafting agent is reduced by 2 parts, and the amount of ethylene-vinyl acetate copolymer 33002 is increased by 2 parts. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0086] The difference between Example 6 and Example 1 is that the number of parts of linear low-density polyethylene is reduced by 2 parts and the number of parts of maleic anhydride grafting agent is increased by 2 parts. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0087] The difference between Example 7 and Example 1 is that the number of flame retardants is reduced by 3 parts and the number of ceramic-forming additives is increased by 3 parts. As can be seen from the data in Table 1 and Table 2, both meet the basic performance indicators.

[0088] The difference between Comparative Example 1 and Example 1 is that the ethylene-vinyl acetate copolymer 6110M and ethylene-vinyl acetate copolymer 33002 were used, with the part of EVA 6110M increased to 20 parts and the part of EVA 33002 decreased to 0 parts. Although the formulation cost decreased, the elongation at break of the material was not up to standard, and the melt flow rate of EVA 6110M was relatively high, which resulted in poor combustion shelling after extrusion into cables, making it difficult to meet the combustion dripping index.

[0089] The difference between Comparative Example 2 and Example 1 is that the ethylene-vinyl acetate copolymer 6110M and maleic anhydride grafting agent were used. The amount of maleic anhydride grafting agent was reduced to 0 parts, and the reduced amount of maleic anhydride grafting agent was increased in EVA6110M. Since the amount of compatibilizer was reduced to 0 parts, the compatibility between the resin and the powder decreased significantly, the elongation at break was not up to standard, and the combustion dripping index could not be met.

[0090] The difference between Comparative Example 3 and Example 1 is that the amount of lubricant was reduced by 0.3 parts, which resulted in poor material processing performance and failure to meet the requirements for elongation at break and combustion dripping.

[0091] This invention illustrates the detailed process equipment and process flow through the above embodiments. However, this invention is not limited to the detailed process equipment and process flow described above, meaning that this invention does not necessarily depend on the detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

[0092] The embodiments of the present invention have been described in detail above, and the B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 prepared in the examples are all qualified products and meet the performance preparation requirements. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0094] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0, characterized in that, By weight, it comprises the following raw materials:

2. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 1, characterized in that, It also includes one or more of the following conditions: A1) The ethylene-vinyl acetate copolymer is a mixture of two copolymers with different vinyl acetate VA contents, and the VA contents of the two different vinyl acetates are both greater than 25%. A2) The linear low-density polyethylene has a density of 0.915-0.945 g / cm³. 3 .

3. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 2, characterized in that, It also includes one or more of the following conditions: A11) In feature A1), the ethylene-vinyl acetate copolymer is two of the following: BASF Yangzi 6110M, Taiju 33002, and DowDuPont 220W. In feature A2), linear low-density polyethylene is one or more of Borealis bimodal polyethylene and Saudi 218WJ.

4. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 as described in claim 1, characterized in that, It also includes one or more of the following conditions: B1) The density of the ethylene-octene copolymer is 0.85-0.95 g / cm³. 3 Melt index is 0.5-2 g / 10 min; B2) The grafting rate of the maleic anhydride grafting agent is greater than 0.8%.

5. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 4, characterized in that, It also includes one or more of the following conditions: B11) In feature B1), the ethylene-octene copolymer is one or more of DowDuPont's 8100 and Exxon's 3980FL; B21) In feature B2), the maleic anhydride grafting agent is one or more of Yunfeiyang Plastics' Y5102 and Nengzhiguang's MC509.

6. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 1, characterized in that, The carbon black content in the masterbatch shall not be less than 45% and the dispersion grade shall not be less than 2.

7. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 1, characterized in that, It also includes one or more of the following conditions: C1) The flame retardant is one or a combination of at least two of aluminum hydroxide, magnesium hydroxide, and phosphorus silicon compounds; C2) The particle size of the ceramic-forming aid is 5-10 micrometers; C3) The ceramic-forming aid is one or more of wollastonite and ceramic powder; C4) The char-forming agent is one or a combination of two of XY101 and CFA; C5) The lubricant is one or a combination of two of the following: imported polyethylene wax with a molecular weight greater than 50,000 or silicone masterbatch with a siloxane content of not less than 50%. The antioxidant described in C6) is a combination of primary antioxidant and secondary antioxidant.

8. The B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to claim 7, characterized in that, It also includes one or more of the following conditions: C11) In feature C1), the particle size D50 of the aluminum hydroxide is less than 3 micrometers; C51) In feature C5), the lubricant is selected from one or more of SR-208 and SR-500; C61) In feature C6), the primary antioxidant is selected from one of hindered phenols 1010 or hindered phenols 1222; C62) In feature C6), the auxiliary antioxidant is selected from one of thioester DSTP and DLTP; In feature C6), the weight ratio of the primary antioxidant to the secondary antioxidant is 1:1 to 3:

1.

9. The method for preparing a B1-grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to any one of claims 1-8, characterized in that, The preparation method includes: mixing ethylene-vinyl acetate copolymer, linear low-density polyethylene, ethylene-octene copolymer, maleic anhydride grafting agent, color masterbatch, and lubricant evenly according to the formula; finally adding flame retardant, ceramicizing agent, charring agent, and antioxidant; and then mixing, extruding, pelletizing, and drying to obtain B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0.

10. The application of the B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material with a combustion dripping grade of d0 according to any one of claims 1-8 in the fields of large industrial equipment and railway signal cables.

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