Low-smoke halogen-free irradiation crosslinking polyolefin sheath material for engineering machinery as well as preparation method and application of low-smoke halogen-free irradiation crosslinking polyolefin sheath material

Abstract

The invention relates to the technical field of cable sheath materials, in particular to an irradiation crosslinking low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery as well as a preparation method and application of the irradiation crosslinking low-smoke halogen-free flame-retardant polyolefin sheath material. The irradiation crosslinking low-smoke halogen-free flame-retardant polyolefin sheath material for the engineering machinery is prepared from the following components in parts by weight: 15 to 30 parts of ethylene-vinyl acetate copolymer, 5 to 15 parts of metallocene polyethylene, 2 to 10 parts of POE (Polyolefin Elastomer), 2 to 10 parts of maleic anhydride grafting agent, 1 to 2 parts of color master batch, 40 to 65 parts of flame retardant, 1 to 5 parts of carbon-forming agent, 0.1 to 1.2 parts of assistant crosslinking agent, 0.2 to 1 part of antioxidant and 0.5 to 2 parts of lubricant. The irradiation crosslinking low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery is excellent in comprehensive performance, excellent in mechanical property, high in toughness, high in tear resistance, high in tensile property, high in wear resistance, high in torque resistance, high in corrosion resistance, low in toxicity index, good in extrusion processability, and capable of meeting the A combustion requirement; the cable sheath layer is very suitable for being used as a communication cable sheath layer of large-scale engineering machinery and shield tunneling machines.

Description

Technical Field

[0001] The invention relates to the technical field of cable sheath materials, and in particular to a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery, and a preparation method and application thereof. Background Art

[0002] Construction machinery cables are cables designed specifically for construction machinery to meet the special requirements of these equipment for cable performance in specific working environments. These cables usually have the characteristics of wear resistance, oil resistance, cold resistance, heat resistance, waterproofness, and corrosion resistance to ensure long-term stable operation in various harsh working environments. The application scope of construction machinery cables includes but is not limited to various construction machinery such as excavators, loaders, bulldozers, rollers, cranes, shield machines, etc.

[0003] Choosing the right cable for construction machinery requires considering multiple factors, including the cable's conductivity, insulation, and environmental resistance. For example, scraper reel cables, also known as JRO cables or mobile towing cables, are specially designed for mobile equipment such as scrapers and are able to maintain good performance during the movement of the machine. This type of cable needs to maintain a stable working state under frequent movement and towing, so it has a special structure and material to ensure its durability and reliability.

[0004] At present, the production of special engineering machinery cables has been localized in China, including the whole vehicle wiring harness. These wiring harnesses are customized according to customer needs to meet the special requirements of specific engineering machinery, especially the engineering cables used in shield machines. The application of engineering machinery cables is not limited to China. With the continuous development of global infrastructure construction, the demand for such cables is also increasing.

[0005] To sum up, construction machinery cable is a special cable designed to meet the high performance and high reliability requirements of construction machinery in various working environments. Its performance and application range are wide, which is of great significance for ensuring the normal operation of construction machinery and extending its service life. Summary of the invention

[0006] The purpose of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery, and a preparation method and application thereof. The prepared low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery has excellent comprehensive performance, superior mechanical properties, high toughness, high tearing, high tensile resistance, high wear resistance, torque resistance, corrosion resistance, low toxicity index, meets the A combustion requirements, and has good extrusion processing performance. It is very suitable as a communication cable sheath layer for large engineering machinery and shield machines, thereby solving the problems in the prior art.

[0007] One of the purposes of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery. To achieve this purpose, the present invention adopts the following technical solutions:

[0008] A low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery, wherein the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery include the following components in parts by weight:

[0009]

[0010] The second object of the present invention is to provide a method for preparing a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery. To achieve this object, the present invention adopts the following technical solutions:

[0011] The preparation method comprises: mixing ethylene-vinyl acetate copolymer, maleic anhydride grafting agent, polyethylene, POE and masterbatch, and then adding flame retardant, carbon forming agent, cross-linking aid, antioxidant and lubricant to obtain a mixture; mixing, extruding, cooling, pelletizing and drying the prepared mixture to obtain the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery.

[0012] The third object of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery and / or the use of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery prepared according to the aforementioned method of the present invention in the field of building wiring and communication cables.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery of the present invention does not require special process requirements. It only needs to cooperate with the formula design requirements and assist certain processing techniques to meet the requirements of a radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery with excellent comprehensive performance, superior mechanical properties, high toughness, high tearing, high tensile resistance, high wear resistance, torque resistance, corrosion resistance, low toxicity index, meet the A combustion requirements, and have good extrusion processing performance. It is very suitable as a communication cable sheath layer for large engineering machinery and shield machines. DETAILED DESCRIPTION

[0015] After a large number of experimental explorations and studies, the inventors of the present invention provide a low-smoke, halogen-free, radiation-crosslinked polyolefin sheath material for engineering machinery. The radiation-crosslinked, low-smoke, halogen-free, flame-retardant polyolefin sheath material for engineering machinery described in the present invention uses ethylene-vinyl acetate copolymer (EVA) and eight-carbon structure POE as matrix resins, which effectively improves the oil resistance, low temperature resistance, stress cracking resistance and aging resistance of the product; metallocene polyethylene is added to increase its tear resistance to prevent the cable sheath from being broken by boulders or sharp objects at the application end, causing the material to be more easily damaged. The present invention improves the tear resistance of the material to effectively solve this problem; the addition of flame retardants can effectively improve the ablation resistance and flame retardant properties of the sheath material and prevent the spread of fire in a fire environment; the addition of carbon forming agents prevents the carbon layer on the surface of the cable from falling off easily after burning, promotes carbonization, thereby inhibiting flame combustion and improving flame retardant properties; maleic anhydride grafting agent can serve as a "bridge" connecting organic matter and inorganic matter, effectively promotes the blending of various components, and as a compatibilizer, gives the final product good properties. The lubricant makes the surface of the product smooth and delicate, eliminates surface burrs, and improves processing performance; in combination with a cross-linking agent, an antioxidant, and a lubricant, the final prepared radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery has excellent comprehensive performance, superior mechanical properties, high toughness, high tearing, high tensile resistance, high wear resistance, torque resistance, corrosion resistance, low toxicity index, meets the A combustion requirements, and has good extrusion processing performance, which is very suitable as a communication cable sheath layer for large engineering machinery and shield machines. On this basis, this application is completed.

[0016]

Low smoke halogen-free radiation cross-linked polyolefin sheath material for construction machinery

[0017] The present invention provides a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery. The raw materials of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery include the following components in parts by weight:

[0018] The weight portion of ethylene-vinyl acetate copolymer is 15-30 parts. For example, it is 15-17 parts, 17-20 parts, 17-25 parts, 17-30 parts, 15-20 parts, 20-25 parts, 25-30 parts, etc. Another example is 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc.

[0019] The weight portion of polyethylene is 5-15 parts, such as 5-10 parts, 10-15 parts, 5-8 parts, 8-15 parts, 8-10 parts, 10-13 parts, 13-15 parts, etc. Another example is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0020] The weight portion of the maleic anhydride grafting agent is 2-10 parts, such as 2-5 parts, 5-10 parts, 5-8 parts, 8-10 parts, etc. Another example is 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0021] The weight proportion of POE is 2-10 parts, such as 2-4 parts, 4-10 parts, 2-5 parts, 5-10 parts, 5-8 parts, 8-10 parts, etc. Another example is 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0022] The weight proportion of the masterbatch is 1-2 parts, for example, 1-1.5 parts, 1.5-2 parts, 1-1.3 parts, 1.3-1.5 parts, 1.5-1.8 parts, 1.8-2 parts, etc. Another example is 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, etc.

[0023] The weight portion of the flame retardant is 40-65 parts. For example, 40-55 parts, 55-65 parts, 40-50 parts, 50-65 parts, 40-45 parts, 45-50 parts, 50-55 parts, 55-60 parts or 60-65 parts. Another example is 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts or 65 parts.

[0024] The weight proportion of the carbon forming agent is 1-5 parts, such as 1-2 parts, 2-5 parts, 2-3 parts, 3-4 parts or 4-5 parts. Another example is 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc. If the weight proportion of the carbon forming agent is small, the crusting property of the material will be greatly reduced during combustion, resulting in unqualified hardness of the carbon layer.

[0025] The weight portion of the auxiliary crosslinking agent is 0.1-1.2 parts, for example, 0.1-0.5 parts, 0.5-1.2 parts, 0.1-0.3 parts, 0.3-0.5 parts, 0.5-0.8 parts or 0.8-1.2 parts, etc. Another example is 0.1 parts, 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 parts, 1.1 parts or 1.2 parts, etc.

[0026] The weight portion of the antioxidant is 0.2-1 part, for example, 0.2-0.5 part, 0.5-0.8 part, 0.2-0.8 part, 0.8-1 part, etc. Another example is 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, etc.

[0027] The weight portion of the lubricant is 0.5-2 parts, for example, 0.5-1.2 parts, 1.2-2 parts, 0.5-1 parts, 1-1.5 parts or 1.5-2 parts, etc. Another example is 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, etc.

[0028] In a specific embodiment, the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery include the following components in parts by weight:

[0029]

[0030] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the VA content in the ethylene-vinyl acetate copolymer is not less than 26%, for example, the VA content in the ethylene-vinyl acetate copolymer is not less than 28%. Another example is 26%-41%, 28%-41%, 28%-33%, 33-40%, 40-41%, etc. Another example is 28%, 33%, 40%, 41%.

[0031] In some embodiments, the ethylene-vinyl acetate copolymer is selected from one or more of Hanhua Petrochemical 1828, Taiho 33003, Arcoma 2805, or Dow 40L-03. It can be a combination of Hanhua 1828 and Dow 40L-03, or a combination of 2805 and Dow 40L-03.

[0032] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, polyethylene plays a role in improving the tear resistance, bending fatigue resistance and heat resistance of the base material and improving the strength. The polyethylene is metallocene polyethylene, and the tear strength shall not be less than 18N / mm. Preferably, the polyethylene is selected from one or more of ExxonMobil's 3518CB, Exxon XP8656ML or Japan Prime's mLLDPE SP0540.

[0033] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the grafting rate of the maleic anhydride grafting agent is greater than or equal to 0.8%, and can be selected to be 0.8-1.0%. When the grafting rate is less than 0.8%, the material will be unqualified in oil resistance.

[0034] In some embodiments, the maleic anhydride grafting agent is one or both of the domestically produced POE grafting agent Y1406 produced by Jiuju or the domestically produced POE grafting agent 5260 produced by Zhongkexianxing.

[0035] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, POE is an ethylene-octene block copolymer, specifically, the molecular chain carbon structure is an eight-carbon structure, and the tensile strength is ≥28MPa. Preferably, the POE is one or more of DowDuPont 8480 or SABIC C3080. If a four-carbon POE, such as Dow 8003, is selected, and an equal amount of it is replaced by an eight-carbon POE in the formula, the material tensile strength and oil resistance margin are not large, and the tear strength is unqualified.

[0036] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the carbon black content of the masterbatch is not less than 45%, and the dispersion grade is not less than grade 2. One or both of the imported masterbatch Cabot 6269 or 2762 can be selected.

[0037] In the low-smoke halogen-free irradiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the flame retardant is any one of aluminum hydroxide, magnesium hydroxide or phosphorus nitrogen flame retardants or a mixture of at least two thereof. Optionally, the flame retardant is a combination of aluminum hydroxide and magnesium hydroxide. Optionally, the D50 particle size of the flame retardant is not higher than 2 μm. When the particle size is greater than 2 μm, as the particle size increases, the mechanical properties of the material decrease and the mechanical properties of the material are deficient, and the tear strength and the oil and chemical resistance of the material are all unqualified. Optionally, the D50 diameter of the flame retardant is less than 1.5-1.8 μm, and optionally, the D50 particle size of the flame retardant is 1.5-2.0 μm. Preferably, the D50 particle size of the flame retardant is 1.8±0.2 μm. The above particle size range is more conducive to material processing. In some embodiments, for example, the D50 diameter of aluminum hydroxide is less than 1.5-1.8 μm.

[0038] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the carbon-forming agent is selected from any one of montmorillonite or a fibrous material with a large aspect ratio of the crystal structure, or a mixture of at least two of them. Optionally, the montmorillonite is surface intercalated, and the fibrous material with a large aspect ratio of the crystal structure has an aspect ratio of at least greater than or equal to 50.

[0039] For example, the carbon former whisker structure is layered, and the surface of the carbon former whisker is treated with an intercalating agent.

[0040] In a specific embodiment, the carbon-forming agent is sepiolite from TOLSa of Spain, with a brand name of SIL-1.

[0041] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the auxiliary cross-linking agent is one or more of triallyl isocyanurate (TAIC) or trimethylolpropane trimethacrylate (TMPTMA), which can effectively reduce the radiation dose and improve the cross-linking degree.

[0042] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the antioxidant is a main antioxidant and an auxiliary antioxidant. Optionally, the main antioxidant is one of hindered phenols 1010 or 1076. The auxiliary antioxidant is any one of thioester type DLTP and phosphite 168 or a mixture of at least two. Further optionally, the antioxidant is a mixture of hindered phenols 1010 and thioester DLTP. The combination of the main and secondary antioxidants has an effect far greater than 1+1>2, and the cost is reduced. Further optionally, the weight ratio of the mixture of hindered phenols 1010 and thioester DLTP is 2:1.

[0043] In the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery provided by the present invention, the lubricant is a silicone masterbatch with a silicone content of not less than 60%, a molecular weight of not less than 1.2 million, and a carrier of silicon dioxide. For example, the lubricant is FD3200 with a fumed silica carrier from domestic boiling point chemical, which has the characteristics of high silicone content, good dispersibility, and not easy to migrate.

[0044]

Preparation method of low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery

[0045] The present invention also provides a method for preparing the aforementioned low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery of the present invention, comprising the following steps:

[0046] Ethylene-vinyl acetate copolymer, maleic anhydride grafting agent, polyethylene, POE and masterbatch are stirred and mixed according to a proportion, and then a flame retardant, a carbon forming agent, a cross-linking agent, an antioxidant and a lubricant are added to obtain a mixture; the prepared mixture is subjected to mixing, extrusion, cooling, pelletizing and drying to obtain the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery.

[0047] In a specific embodiment:

[0048] (1) Ethylene-vinyl acetate copolymer, maleic anhydride grafting agent, POE, polyethylene and masterbatch were mixed in a high-speed mixer at a low speed for 30 seconds to obtain a mixture 1.

[0049] (2) Then, flame retardant, co-crosslinking agent, antioxidant and lubricant were added together with mixture 1 in a high speed mixer and mixed at low speed for 1 minute to obtain mixture 2.

[0050] (3) The mixture 2 prepared in step (2) is mixed in an internal mixer, extruded, cooled, pelletized, and dried to obtain the radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery for locomotives.

[0051] In step (3), a double-layer filter is used in the extrusion process, wherein the mesh number of the inner layer filter is 100 meshes and the mesh number of the outer layer filter is 120 meshes.

[0052] Preferably, the extrusion temperature is 110-150°C, for example, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C.

[0053]

use

[0054] The present invention also provides a use of a low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery in the field of large-scale engineering machinery and shield machines. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery can be used as a sheath layer of communication cables for large-scale engineering machinery and shield machines.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery of the present invention does not require special process requirements. It only needs to cooperate with the formula design requirements and assist certain processing techniques to meet the requirements of a radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery with excellent comprehensive performance, superior mechanical properties, high toughness, high tearing, high tensile resistance, high wear resistance, torque resistance, corrosion resistance, low toxicity index, meet the A combustion requirements, and have good extrusion processing performance. It is very suitable as a communication cable sheath layer for large engineering machinery and shield machines.

[0057] The beneficial effects of the present invention are further illustrated below in conjunction with embodiments.

[0058] In order to make the invention purpose, technical scheme and beneficial technical effect of the present invention clearer, the present invention is further described in detail below in conjunction with examples. However, it should be understood that the examples of the present invention are only for explaining the present invention, not for limiting the present invention, and the examples of the present invention are not limited to the examples given in the specification. The specific experimental conditions or operating conditions not specified in the examples are made under conventional conditions, or are made under the conditions recommended by the material supplier.

[0059] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these explicitly mentioned two devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0060] In the following examples, unless otherwise specified, various raw materials of the present invention can be purchased from the market or prepared according to conventional methods in the art.

[0061] Example 1

[0062] The radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery of the present embodiment 1 comprises the following components in parts by weight:

[0063]

[0064]

[0065] Among them, ethylene-vinyl acetate copolymer is a compound of Hanhua 1828 and Dow 40L-03, among which the VA content of 40L-03 is 12 parts of 40%, and the VA content of 1828 is 5 parts of 28%; the polyethylene is ExxonMobil's metallocene polyethylene 3518CB, the maleic anhydride grafting agent is the domestic POE grafting agent 5260 of Zhongke Xianxing; the POE is DowDuPont's 8480; the masterbatch used is Cabot's 2762, and the carbon black content is 50%; the flame retardant used is imported Russian magnesium hydroxide A5 is compounded with domestic Zhongshun aluminum hydroxide HC9000, with a compounding ratio of 40:25, and the D50 diameter is less than 1.5-1.8μm; the carbon former is sepiolite from Spanish TOLSa, brand SIL-1, and the auxiliary cross-linking agent is TAIC; the antioxidant is a mixture of hindered phenol 1010 and thioester DLTP, and the weight ratio of the main and auxiliary antioxidants is 2:1; the lubricant is FD3200 with a fumed silica carrier from domestic Boiling Point Chemical, which has the characteristics of high silicone content, good dispersibility, and not easy to migrate.

[0066] The preparation method of the radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for locomotives and engineering machinery of this embodiment 1 comprises the following steps:

[0067] By weight, take 17 parts of ethylene-vinyl acetate copolymer, 8 parts of polyethylene, 5 parts of maleic anhydride grafting agent, 4 parts of POE, and 2 parts of black masterbatch, accurately measure and put them into the high-speed mixer, run at low speed for 3 minutes, then accurately weigh 65 parts of flame retardant, 2 parts of carbon forming agent, 0.8 parts of co-crosslinking agent, 0.4 parts of main and auxiliary antioxidants in total, and 1.2 parts of lubricant in the mixing kettle, and mix at high speed for 1 minute.

[0068] The above-mentioned uniformly mixed raw materials are evenly plasticized in an internal mixer at a plasticizing temperature of 165-168°C, and then sent to a double-cone feeding hopper through an elevator, and then re-mixed, plasticized, extruded, pelletized, cooled and packaged through a twin-screw extruder unit. The extrusion process uses an extruder with a double-layer filter screen, the inner filter screen has a mesh number of 100 meshes, the outer filter screen has a mesh number of 120 meshes, and the extrusion temperatures are 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, and 150°C.

[0069] Example 2

[0070] The difference between Example 2 and Example 1 is that the ethylene-vinyl acetate copolymers used are EVA2805 and Dow 40L-03, wherein, by weight, the amount of EVA2805 is 12 parts, and the amount of 40L-3 is 5 parts, with a ratio of 12:5, and the rest are the same as in Example 1.

[0071] Example 3

[0072] The difference between Example 3 and Example 1 is that the amount of maleic anhydride POE grafting agent used is reduced by 2 parts, and the reduced amount is added to the amount of mLLDPE3518CB. The rest is the same as Example 1.

[0073] Example 4

[0074] The difference between Example 4 and Example 1 is that the number of POE used is increased by 2, and the rest is the same as Example 1.

[0075] Example 5

[0076] The difference between Example 5 and Example 1 is that the flame retardant used is a formula of aluminum hydroxide and magnesium hydroxide, the D50 particle size is 1.5-2.0 μm, the ratio is 10:55, and the rest is the same as Example 1.

[0077] Example 6

[0078] The difference between Example 6 and Example 1 is that the amount of the auxiliary cross-linking agent used is increased to 0.4 parts, and the rest is the same as Example 1.

[0079] Example 7

[0080] The difference between Example 7 and Example 1 is that the amount of lubricant used is reduced to 0.4 parts, and the rest is the same as Example 1.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is that the VA content in the ethylene-vinyl acetate copolymer used is less than 26%, and Yanshan Petrochemical EVA18J3 with a VA content of 18% is used to replace 1828, and the rest is the same as Example 1.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 1 is that the grafting rate of the maleic anhydride grafting agent used is <0.8%, and the grafting rate is 0.5%. The other conditions are the same as those in Example 1.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 1 is that the D50 particle size of the flame retardant used is 2.5-3.0 μm, and the rest is the same as Example 1.

[0087] Comparative Example 4

[0088] The difference between this comparative example and Example 1 is that Dow 8003, a POE with a molecular structure of four carbon atoms, is used to replace the POE with an eight-carbon structure in the formula in equal amounts. The rest is the same as Example 1.

[0089] Comparative Example 5

[0090] The difference between this comparative example and Example 1 is that 2 parts of the carbon forming agent are reduced, 2 parts of the flame retardant aluminum hydroxide are added, and the rest are the same as Example 1.

[0091] Comparative Example 6

[0092] The difference between this comparative example and Example 1 is that 2 parts of the carbon forming agent are reduced, 2 parts of the flame retardant magnesium hydroxide are added, and the rest are the same as Example 1.

[0093] The radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery prepared in the above-mentioned Examples 1-7 and Comparative Examples 1-6 was subjected to performance and preliminary process tests, and the results are shown in Table 1 below.

[0094] The test standards used are as follows:

[0095] The density test standard is carried out in accordance with GB / T 1033, the melt flow rate test standard is carried out in accordance with GB / T 3682, the tensile strength and elongation at break test standard is carried out in accordance with GB / T 1040, the hot extension test standard is carried out in accordance with GB / T2951.21, the kerosene resistance, 902# mineral oil resistance and 903# fuel oil resistance test standard is carried out in accordance with GB / T2951.21, the oxalic acid solution and sodium hydroxide solution resistance test standard is carried out in accordance with EN:50264, the oxygen index is carried out in accordance with GB / T2406, and the tear performance is carried out in accordance with JB / T 10696.7.

[0096] Table 1: Performance comparison analysis table of the embodiments

[0097]

[0098]

[0099] Table 2: Comparative performance analysis table

[0100]

[0101] It can be seen from Table 1 that the radiation cross-linked low-smoke halogen-free flame-retardant polyolefin sheath material for engineering machinery of the present invention has excellent comprehensive performance, superior mechanical properties, high toughness, high tearing, high tensile strength, high wear resistance, torque resistance, corrosion resistance, low toxicity index, meets the A combustion requirements, and has good extrusion processing performance, and is very suitable as a communication cable sheath layer for large engineering machinery and shield machines.

[0102] It can be seen from Table 2 that the VA content of the ethylene-vinyl acetate copolymer used in Comparative Example 1 is less than 26%, and the use of Yanshan Petrochemical EVA18J3 with a VA content of 18% to replace 1828 directly leads to the material's unqualified oil resistance.

[0103] The grafting rate of the maleic anhydride grafting agent used in Comparative Example 2 is less than 0.8%, and the grafting rate is 0.5%, which directly leads to the material failing to meet the oil resistance standard.

[0104] In Comparative Example 3, the flame retardant used has a D50 particle size of 2.5-3.0 μm, and the aluminum hydroxide particle size is slightly lower than the preferred value. The increase in particle size leads to a decrease in the mechanical properties of the material, resulting in poor mechanical properties of the material, and its tear strength and oil and chemical resistance are all unqualified.

[0105] Comparative Example 4 uses Dow 8003, a four-carbon POE, to replace the eight-carbon POE in the formula in equal amounts, resulting in a small margin in the tensile strength and oil resistance of the material, and unqualified tear strength.

[0106] In Comparative Example 5, the amount of carbon-forming agent is reduced by 2 parts, and the amount of flame retardant aluminum hydroxide is increased by 2 parts. The amount of carbon-forming agent is small, and the amount of flame retardant aluminum hydroxide is increased. Although the flame retardancy is increased, its carbon-forming crusting property is reduced, resulting in a decrease in flame retardancy and failure to meet the standards.

[0107] In Comparative Example 6, the amount of carbon-forming agent is reduced by 2 parts, and the amount of flame retardant magnesium hydroxide is increased by 2 parts. The amount of carbon-forming agent is small, and the amount of flame retardant magnesium hydroxide is increased. Although the amount of flame retardant is increased, its carbon-forming crusting property is reduced, resulting in a decrease in flame retardancy and failure to meet the standards.

[0108] The present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0109] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0110] 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 further describe various possible combinations.

[0111] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery, wherein the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery include the following components in parts by weight:

2. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: A1) the VA content of the ethylene-vinyl acetate copolymer is not less than 26%; A2) The polyethylene is a metallocene polyethylene.

3. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: A11) the ethylene-vinyl acetate copolymer is selected from one or more of Hanwha Petrochemical 1828, Taiho 33003, Arco 2805 or Dow 40L-03; A12) The tear strength of the polyethylene shall not be less than 18N / mm; A13) The polyethylene is selected from one or more of ExxonMobil's 3518CB, Exxon XP8656ML or Japan Prime's mLLDPE S0540.

4. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: B1) the grafting rate of the maleic anhydride grafting agent is greater than or equal to 0.8%; B2) The POE is an ethylene-octene block copolymer.

5. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: B11) the maleic anhydride grafting agent is one or both of the domestically produced POE grafting agent Y1406 produced by Jiuju or the domestically produced POE grafting agent 5260 produced by Zhongke Xianxing; B21) the POE is an ethylene-octene block copolymer having an eight-carbon molecular chain carbon structure and a tensile strength of ≥28MP; B22) The POE is one or more of DowDuPont 8480 or SABIC C3080.

6. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: C1) the carbon black content of the masterbatch is not less than 45% and the dispersion grade is not less than grade 2; C2) the flame retardant is selected from any one of aluminum hydroxide, magnesium hydroxide or phosphorus nitrogen flame retardants or a mixture of at least two thereof; C3) the particle size of the flame retardant is not higher than 2 μm; C4) the carbon-forming agent is selected from any one of montmorillonite and a fibrous material having a large aspect ratio of a crystal structure, or a mixture of at least two thereof; C5) the auxiliary crosslinking agent is selected from one or two of triallyl isocyanurate and trimethylolpropane trimethacrylate; C6) the antioxidant is a primary antioxidant and an auxiliary antioxidant; C7) The lubricant is a silicone masterbatch with a silicone content of not less than 60%, a molecular weight of not less than 1.2 million, and a carrier of silicon dioxide.

7. The low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 1, characterized in that: Also includes any one or more of the following features: C21) the flame retardant is a combination of aluminum hydroxide and magnesium hydroxide; C31) the flame retardant has a D50 particle size of 1.8±0.2 μm; C41) the montmorillonite is subjected to surface intercalation treatment, and the fibrous material with a large aspect ratio of the crystal structure has an aspect ratio of at least greater than or equal to 50; C61) the primary antioxidant is selected from one of the hindered phenols 1010 or 1076; C62) the auxiliary antioxidant is selected from any one of thioester type DLTP and phosphite type 168 or a mixture of at least two thereof; C71) The lubricant is FD3200 with fumed silica carrier from domestically produced Boiling Point Chemical.

8. The method for preparing the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to any one of claims 1 to 7, characterized in that: The preparation method comprises: mixing ethylene-vinyl acetate copolymer, maleic anhydride grafting agent, polyethylene, POE and masterbatch, and then adding flame retardant, carbon forming agent, cross-linking aid, antioxidant and lubricant to obtain a mixture; mixing, extruding, cooling, pelletizing and drying the prepared mixture to obtain the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery.

9. The method for preparing the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to claim 8, characterized in that: Also includes any one or more of the following features: D1) Double-layer filter screen is used in the extrusion process; D2) The extrusion temperature is 110-150°C.

10. Use of the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery according to any one of claims 1 to 7 and / or the low-smoke halogen-free radiation cross-linked polyolefin sheath material for engineering machinery prepared according to the preparation method according to claim 8 or 9 in the field of large-scale engineering machinery and shield machines.

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