Low-smoke halogen-free irradiation crosslinking polyolefin insulating material for thin-wall cable as well as preparation method and application of low-smoke halogen-free irradiation crosslinking polyolefin insulating material

Abstract

The invention discloses a low-smoke halogen-free irradiation cross-linked polyolefin insulating material for a thin-wall cable as well as a preparation method and application of the low-smoke halogen-free irradiation cross-linked polyolefin insulating material. The invention discloses a low-smoke halogen-free irradiation crosslinking polyolefin insulating material for a thin-wall cable. Comprising the following components: 15%-25% of an ethylene-vinyl acetate copolymer, 5%-10% of an ethylene-octylene copolymer, 3%-10% of a maleic anhydride grafting agent, 55%-70% of a halogen-free flame retardant, 0.1%-1% of an assistant crosslinker, 0.5%-2% of an antioxidant, 0.5%-2% of a lubricant and 0.5%-2% of a silane coupling agent. The low-smoke halogen-free irradiation crosslinking polyolefin insulating material for the thin-wall cable has the advantages of excellent comprehensive performance, excellent mechanical property, strong flexibility, high temperature resistance, long-term high-temperature aging resistance, good flame retardant property and good processability, and is especially suitable for the field of building wiring, communication cables and other insulating cables.

Description

Technical Field

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

[0002] With the rapid development of science and technology, the integration of electronic products is constantly improving, and the requirements for cable diameters are getting smaller and smaller. At the same time, the increase in various electrical equipment has caused a rapid surge in electricity consumption. Full-load or overload operation of wires and lines has become the norm. Due to the poor heat resistance of traditional communication cables, wires are prone to failure due to rapid aging. In recent years, fire accidents caused by aging of wires and lines have increased year by year, which has put forward higher requirements for the flame retardancy, temperature resistance and environmental protection of cable materials. Traditional flame-retardant and heat-resistant cable materials mostly contain halogen flame retardants. Although they have high flame retardant efficiency, they will produce toxic gases when burned and do not meet modern environmental protection standards. Therefore, the development of high-performance polyolefin cable materials that are highly flame-retardant, high-temperature resistant and suitable for thin-walled cables has broad application prospects. Summary of the invention

[0003] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables and a preparation method and application thereof. The prepared low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables has excellent comprehensive properties, superior mechanical properties, strong flexibility, high temperature resistance, resistance to long-term high temperature aging, good flame retardant properties, good fluidity and formability during processing, and is particularly suitable for fields such as building wiring and communication cables. In addition, the present invention also provides a preparation process of the insulation material to realize industrial production, thereby solving the problems in the prior art.

[0004] One of the purposes of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables. To achieve this purpose, the present invention adopts the following technical solutions:

[0005] A low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables, wherein the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables include the following components by weight percentage:

[0006]

[0007]

[0008] The second object of the present invention is to provide a method for preparing a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables. To achieve this object, the present invention adopts the following technical solutions:

[0009] The preparation method comprises: uniformly mixing ethylene-vinyl acetate copolymer, ethylene-octene copolymer and maleic anhydride grafting agent, then adding a mixture of lubricant, antioxidant, auxiliary cross-linking agent and silane coupling agent, fully mixing and then adding halogen-free flame retardant, mixing, extruding, granulating, drying and screening, and then processing into cables and then irradiating and cross-linking, with an irradiation dose of 3-10 Mrad, to obtain the low-smoke halogen-free irradiation cross-linked polyolefin insulation material for thin-walled cables.

[0010] The third object of the present invention is to provide a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables and / or the use of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables prepared according to the aforementioned method of the present invention in the field of building wiring and communication cables.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention has excellent comprehensive properties, superior mechanical properties, strong flexibility, high temperature resistance, long-term high temperature aging resistance, good flame retardancy, and good processability. Specifically, under non-irradiated conditions, the tensile strength and elongation at break of the insulation material are respectively greater than 10MPa and greater than 150%; after the insulation material is irradiated and cross-linked, it still has excellent mechanical properties after being kept at a high temperature of 180°C for 168 hours; the flame retardancy is good, the material oxygen index is greater than 40%, and after being cabled, it meets the requirements of bundled Class B combustion and Class B1 combustion. Since no halogen flame retardant, antimony flame retardant or red phosphorus and other synergistic flame retardants are added to the system, the smoke emission is small and the environmental pollution is small. DETAILED DESCRIPTION

[0013] After a lot of experimental exploration and research, the inventor of the present invention provides a low-smoke, halogen-free, radiation-cross-linked polyolefin insulation material for highly flame-retardant thin-walled cables designed specifically for thin-walled cables. The cable material is intended to meet the urgent needs of modern communications, electronics, home appliances and other industries for miniaturization, lightweight and high safety of cable materials, especially in the context of increasingly stringent environmental protection requirements, to achieve low-smoke, halogen-free and flame-retardant cable materials.

[0014] Specifically: a blend of two resins, ethylene-vinyl acetate copolymer and ethylene-octene copolymer (POE), is used as a base material to improve the flexibility and processability of the material, wherein the mechanical properties and flame retardant properties of the material are improved by compounding two ethylene-vinyl acetate copolymers. Maleic anhydride grafting agent acts as a "bridge" connecting inorganic and organic matter, and mainly plays a role of volume expansion in the system. The halogen-free flame retardant is mainly a mixture of aluminum hydroxide / magnesium hydroxide and boron flame retardant, which improves the flame retardant grade and oxygen index through a synergistic flame retardant effect, while reducing smoke release and the generation of toxic gases. Silane coupling agent can promote the dispersibility of fillers, further improve the oxygen index of materials, and improve flame retardant properties. With appropriate amounts of co-crosslinking agents, antioxidants and lubricants, the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables has excellent comprehensive properties and good molding and processing properties. On this basis, this application is completed.

[0015]

Low smoke halogen-free radiation cross-linked polyolefin insulation material for thin-wall cables

[0016] The present invention provides a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables. The raw materials of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables include the following components by weight percentage:

[0017] The weight percentage of ethylene-vinyl acetate copolymer is 15%-25%. For example, 15%-17%, 17%-25%, 15%-20%, 20%-20%, 17%-20%, 20%-23% or 23%-25%, etc. Another example is 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24 or 25%, etc.

[0018] The weight percentage of the ethylene-octene copolymer is 5%-10%, such as 5%-7%, 7%-10%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, etc. Another example is 5%, 6%, 7%, 8%, 9% or 10%.

[0019] The weight percentage of the maleic anhydride grafting agent is 3%-10%, such as 3%-4%, 4%-10%, 4%-8%, 8%-10%, etc. Another example is 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.

[0020] The weight percentage of the halogen-free flame retardant is 55%-70%. For example, it is 55%-68%, 68%-70%, 55%-60%, 60%-65%, 65%-70%, etc. Another example is 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% or 70%, etc.

[0021] The weight percentage of the auxiliary cross-linking agent is 0.1%-1%, for example, 0.1%-0.5%, 0.5%-1%, 0.1%-0.3%, 0.3%-0.5%, 0.5%-0.8%, 0.8%-1%, etc. Another example is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0022] The weight percentage of the antioxidant is 0.5%-2%, for example, 0.5%-0.6%, 0.6%-1%, 1%-2%, 0.6%-2%, 0.5%-1%, 1%-1.5%, 1.5%-2%, etc. Another example is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2.0%, etc.

[0023] The weight percentage of the lubricant is 0.5%-2%, for example, 0.5%-1%, 1%-1.5%, 0.5%-1.5%, 1.5%-2%, etc. Another example is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%, etc.

[0024] The weight percentage of the silane coupling agent is 0.5%-2%, such as 0.5%-1%, 0.5%-1%, 0.5%-1%, 1%-1.5%, 1.5%-2%, etc. Another example is 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0025] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the ethylene-vinyl acetate copolymer is one or both of a first ethylene-vinyl acetate copolymer (ethylene-vinyl acetate copolymer with high VA content) and a second ethylene-vinyl acetate copolymer (ethylene-vinyl acetate copolymer with low VA content), wherein the VA content in the first ethylene-vinyl acetate copolymer is 33-45%, which can be 33-41%, 41-45%, 33-40%, 40-45%, 40-41%, etc. The VA content in the second ethylene-vinyl acetate copolymer is 22-28%, which can be 22-24%, 24-28%, etc.

[0026] Further, in some embodiments, the first ethylene-vinyl acetate copolymer may be, for example, EV40W from Dow Chemical, Z4003AC from Celanese, etc. The second ethylene-vinyl acetate copolymer may be, for example, 2803W from Celanese, 24J6 from Yanshan Petrochemical, etc.

[0027] Optionally, the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables include 4%-10% of the first ethylene-vinyl acetate copolymer and 10%-20% of the second ethylene-vinyl acetate copolymer by weight percentage. Optionally, the weight percentage of the first ethylene-vinyl acetate copolymer can be, for example, 10%-11% or 11%-20%.

[0028] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the melt index of the ethylene-octene copolymer is less than or equal to 5 g / 10 min. Optionally, the melt index of the ethylene-octene copolymer may be, for example, less than or equal to 4 g / 10 min, less than or equal to 3 g / 10 min, less than or equal to 2 g / 10 min, less than or equal to 1.8 g / 10 min, less than or equal to 1.5 g / 10 min, less than or equal to 1.2 g / 10 min, less than or equal to 1 g / 10 min, less than or equal to 0.8 g / 10 min, or less than or equal to 0.5 g / 10 min.

[0029] Optionally, the ethylene-octene copolymer is one or both of SABIC's C0570D and SABIC's C5070D.

[0030] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the grafting rate of the maleic anhydride grafting agent is greater than or equal to 0.8%. Optionally, the grafting rate of the maleic anhydride grafting agent ranges from 0.8% to 2%, 0.8% to 1.2%, etc. Preferably, it is MD715 from Mitsui of Japan.

[0031] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the flame retardant is any one of aluminum hydroxide, magnesium hydroxide and a boron flame retardant or a mixture of at least two thereof. Optionally, the D50 particle size of the flame retardant is less than 2 μm. Optionally, the D50 particle size of the flame retardant is in the range of 0.8-1.5 μm.

[0032] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the auxiliary cross-linking agent is at least one of trimethylolpropane trimethacrylate, triallyl isocyanurate and dicumyl peroxide.

[0033] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the antioxidant is a main antioxidant and an auxiliary antioxidant. Optionally, the main antioxidant is one of hindered phenols 1010, 1076 or 330. The auxiliary antioxidant is any one of thioester type DSTP, DLTP, anti-copper agent 1024 and phosphite 168 or a mixture of at least two. Among them, the anti-copper agent is a type of antioxidant. The anti-copper agent, also known as a heavy metal ion passivator, has the main function of complexing transition metal ions to prevent them from catalyzing the oxidative degradation reaction of polymer resins. Anti-copper agents are usually used in plastic products to extend the service life and stability of plastics.

[0034] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the lubricant is one or both of imported polyethylene wax with a molecular weight greater than or equal to 50,000 or silicone masterbatch with a siloxane content of not less than 50%. For example, the lubricant is SR-500 from Guangzhou Yinyuan.

[0035] In the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, the silane coupling agent is selected from 11-100 produced by Dow Corning of the United States.

[0036] [Preparation method of low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables]

[0037] The present invention also provides a method for preparing the aforementioned low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention, comprising the following steps:

[0038] Ethylene-vinyl acetate copolymer, ethylene-octene copolymer and maleic anhydride grafting agent are mixed uniformly according to a proportion, and then a mixture of a lubricant, an antioxidant, a cross-linking aid and a silane coupling agent is added, and after being fully mixed, a halogen-free flame retardant is added, and after mixing, extrusion, granulation, drying and screening, a low-smoke halogen-free polyolefin insulation material is obtained. After subsequent processing into a cable, it is irradiated and cross-linked, and the irradiation dose is 3-10Mrad to obtain the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables.

[0039]

use

[0040] The present invention also provides a use of a low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables in the fields of building wiring and communication cables. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables can be used for the preparation of building wiring and communication cables.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention has excellent comprehensive properties, superior mechanical properties, strong flexibility, high temperature resistance, long-term high temperature aging resistance, good flame retardancy, and good processability. Specifically, under non-irradiated conditions, the tensile strength and elongation at break of the insulation material are respectively greater than 10MPa and greater than 150%; after the insulation material is irradiated and cross-linked, it still has excellent mechanical properties after being kept at a high temperature of 180°C for 168 hours; the flame retardancy is good, the material oxygen index is greater than 40%, and after being cabled, it meets the requirements of bundled Class B combustion and Class B1 combustion. Since no halogen flame retardant, antimony flame retardant or red phosphorus and other synergistic flame retardants are added to the system, the smoke emission is small and the environmental pollution is small.

[0043] The beneficial effects of the present invention are further illustrated below in conjunction with embodiments.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Example 1

[0048] The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of this embodiment comprises the following components by weight percentage:

[0049]

[0050] Among them, the VA content of ethylene-vinyl acetate copolymer with high VA content is 41%, model EV40W of Dow Chemical, with a mass fraction of 6%, and the VA content of ethylene-vinyl acetate copolymer with low VA content is 28%, model 2803W of Celanese, with a mass fraction of 11%. The compounding of the two ethylene-vinyl acetate copolymers can improve the inorganic filling rate, optimize the flame retardant properties and improve the mechanical properties of the material; the model of ethylene-octene copolymer is C0570D of Sabic; the grafting rate of maleic anhydride grafting agent is 1.5%, model MD715 of Mitsui Chemicals; the antioxidant is a compound mixture of 0.3 parts of hindered phenol 1010, 0.2 parts of thioester DLTP and 0.1 parts of anti-copper agent 1024; the auxiliary cross-linking agent is triallyl isocyanurate (TAI C); the lubricant is a silicone masterbatch with a siloxane content of 50%, the carrier is a linear low-density polyethylene, and the model is SR-500 produced by Guangzhou Yinyuan; the flame retardant is a compound mixture of 60% magnesium hydroxide and 8% zinc borate, among which magnesium hydroxide (ZH-E6) with a stearate surface treatment produced by Jiangsu Zehui is used, and the D50 particle size is less than 1.5μm, the zinc borate is selected to have a moisture content of less than or equal to 0.5%, and the D50 particle size is less than or equal to 4μm, and the silane coupling agent is 11-100 produced by Dow Corning of the United States.

[0051] The preparation method of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of this embodiment is as follows:

[0052] Ethylene-vinyl acetate copolymer, ethylene-octene copolymer and maleic anhydride grafting agent are mixed uniformly according to the formula, and then a mixture of lubricant, antioxidant, auxiliary cross-linking agent and silane coupling agent is added, and after being fully mixed uniformly, a halogen-free flame retardant is added, and the mixture is subjected to banburying, extrusion, granulation, drying and screening, and then processed into cables and irradiated and cross-linked, with an irradiation dose of 3-10 Mrad, to obtain the low-smoke halogen-free irradiation cross-linked polyolefin insulation material for thin-walled cables.

[0053] Example 2

[0054] The difference between this embodiment and embodiment 1 is that the type of ethylene-vinyl acetate copolymer is changed. The ethylene-vinyl acetate copolymer with high VA content is Celanese Z4003AC with a VA content of 40%. The other components are the same as those in embodiment 1.

[0055] The preparation method of this embodiment is also the same as that of embodiment 1. Unless otherwise specified, the preparation methods of subsequent embodiments and comparative examples are the same as that of embodiment 1.

[0056] Example 3

[0057] The difference between this embodiment and embodiment 1 is that the type of the ethylene-vinyl acetate copolymer with low VA content is changed to 24J6 produced by Yanshan Petrochemical, with a VA content of 24%. The rest is the same as in embodiment 1.

[0058] Example 4

[0059] The difference between this embodiment and embodiment 1 is that the type of ethylene-octene copolymer is changed to C5070D of Sabic, and the melt index is 5.0 g / 10 min. The others are the same as those in embodiment 1.

[0060] Example 5

[0061] The difference between this embodiment and embodiment 1 is that the grafting rate of the maleic anhydride grafting agent is 0.8%, and the other aspects are the same as those of embodiment 1.

[0062] Example 6

[0063] The difference between this embodiment and embodiment 1 is that the amount of the auxiliary cross-linking agent is 1%, and the other aspects are the same as those of embodiment 1.

[0064] Example 7

[0065] The difference between this embodiment and the first embodiment is that the antioxidant is 0.8 parts of 1010, 0.4 parts of DLTP and 0.2 parts of the anti-copper agent 1024, and the rest is the same as the first embodiment.

[0066] Example 8

[0067] The difference between this embodiment and embodiment 1 is that the amount of lubricant used is 2%, and the other aspects are the same as those of embodiment 1.

[0068] Example 9

[0069] The difference between this embodiment and embodiment 1 is that the ethylene-vinyl acetate copolymer 2803W with low VA content is completely replaced by the ethylene-vinyl acetate copolymer EV40W with high VA content, and the rest is the same as embodiment 1.

[0070] Example 10

[0071] The difference between this embodiment and embodiment 1 is that the ethylene-vinyl acetate copolymer EV40W with a high VA content is completely replaced by the ethylene-vinyl acetate copolymer 2803W with a low VA content, and the rest is the same as embodiment 1.

[0072] Embodiment 11

[0073] The difference between this embodiment and embodiment 1 is that the dosage of the synergistic flame retardant zinc borate is reduced to 2%, and the reduced portion is completely replaced by magnesium hydroxide. The rest is the same as embodiment 1.

[0074] Example 12

[0075] The difference between this embodiment and embodiment 1 is that the dosage of the silane coupling agent is reduced to 0.5%, and the other aspects are the same as those of embodiment 1.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is that the resin is changed, and the specific composition is:

[0078]

[0079] The specific types of the components are substantially the same as those in Example 1, wherein the two VA contents of ethylene-vinyl acetate copolymers are each reduced by 1.5% and added to the ethylene-octene copolymer.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 1 is that the ethylene-octene copolymer is not contained, and the amount of the reduced ethylene-octene copolymer is added to the two ethylene-vinyl acetate copolymers on average to ensure that the total amount of the resin matrix remains unchanged. The rest is the same as Example 1.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 1 is that it does not contain maleic anhydride grafting agent, and the reduced amount of maleic anhydride grafting agent is evenly added to the remaining resins to ensure that the total amount of the resin matrix remains unchanged. The rest is the same as Example 1.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 1 is that the antioxidant 1010 is replaced by 2246, and the rest is the same as Example 1.

[0086] Comparative Example 5

[0087] The difference between this comparative example and Example 1 is that the amount of magnesium hydroxide used is reduced by 4%, the amount of ethylene-octene copolymer used is increased by 4%, and the other aspects are the same as those of Example 1.

[0088] Comparative Example 6

[0089] The difference between this comparative example and Example 1 is that the amount of magnesium hydroxide used is increased by 4%, and the amount of ethylene-octene copolymer used is reduced by 4%. The other aspects are the same as those of Example 1.

[0090] The performance of the thin-walled cables prepared in Examples 1 to 12 and Comparative Examples 1 to 6 was tested using low-smoke halogen-free radiation cross-linked polyolefin insulation material. The test results are shown in Table 1.

[0091] Among them, the test standards are as follows:

[0092] 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 test standard is carried out in accordance with GB / T 1040, the elongation at break test standard is carried out in accordance with GB / T 1040, the oxygen index test standard is carried out in accordance with GB / T2406.2-2009, the heat aging is carried out in accordance with GB / T2951.12-2008, and the technical indicators are carried out in accordance with GB / T 32129-2015.

[0093] Table 1: Performance comparison analysis table

[0094]

[0095]

[0096] It can be seen from Table 1 that the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables of the present invention has excellent comprehensive properties, superior mechanical properties, high temperature resistance, resistance to long-term high temperature aging, good flame retardancy, good fluidity and formability during processing, and is particularly suitable for the fields of building wiring and communication cables.

[0097] Although the change in the resin ratio in Comparative Example 1 is helpful for the mechanical properties, the flame retardant properties of the material are reduced.

[0098] Comparative Example 2 does not contain ethylene-octene copolymer, which will improve the flame retardant properties of the material, but reduce the mechanical properties and thermal aging properties.

[0099] Comparative Example 3 does not contain maleic anhydride grafting agent, and all properties of the material are severely deteriorated.

[0100] In Comparative Example 4, the type of antioxidant was changed, and the mechanical properties of the material did not change much, but the thermal aging performance decreased.

[0101] In Comparative Example 5, the magnesium hydroxide content is reduced and the flame retardant properties of the material are reduced.

[0102] In Comparative Example 6, the magnesium hydroxide content is increased, the flame retardant properties of the material are improved, but the fluidity and mechanical properties are greatly reduced.

[0103] 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.

[0104] 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.

[0105] 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.

Claims

1. A low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables, wherein the raw materials of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables include the following components by weight percentage:

2. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 1, characterized in that: The ethylene-vinyl acetate copolymer is one or both of a first ethylene-vinyl acetate copolymer and a second ethylene-vinyl acetate copolymer.

3. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 2, characterized in that: Also includes any one or more of the following features: A1) the VA content in the first ethylene-vinyl acetate copolymer is 33-45%; A2) the VA content of the second ethylene-vinyl acetate copolymer is 22-28%; A3) The raw materials of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables include 4%-10% of a first ethylene-vinyl acetate copolymer and 10%-20% of a second ethylene-vinyl acetate copolymer by weight percentage.

4. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 3, characterized in that: Also includes any one or more of the following features: A11) the first ethylene-vinyl acetate copolymer is one of EV40W of Dow Chemical and Z4003AC of Celanese; A21) The second ethylene-vinyl acetate copolymer is one of Celanese's 2803W and Yanshan Petrochemical's 24J6.

5. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 1, characterized in that: Also includes any one or more of the following features: B1) the melt index of the ethylene-octene copolymer is less than or equal to 5 g / 10 min; B2) The grafting rate of the maleic anhydride grafting agent is greater than or equal to 0.8%.

6. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 1, characterized in that: Also includes any one or more of the following features: B11) the ethylene-octene copolymer is one or both of SABIC's C0570D and SABIC's C5070D; B21) The maleic anhydride grafting agent is MD715 produced by Mitsui Chemicals.

7. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 1, characterized in that: Also includes any one or more of the following features: C1) the flame retardant is any one of aluminum hydroxide, magnesium hydroxide and a boron flame retardant or a mixture of at least two thereof; C2) the D50 particle size of the flame retardant is less than 2 μm; C3) the auxiliary cross-linking agent is at least one of trimethylolpropane trimethacrylate, triallyl isocyanurate, and dicumyl peroxide; C4) the antioxidant is a primary antioxidant and an auxiliary antioxidant; C5) The lubricant is one or both of imported polyethylene wax with a molecular weight greater than or equal to 50,000 or silicone masterbatch with a siloxane content of not less than 50%; C6) The silane coupling agent is selected from Dow Corning 11-100 of the United States.

8. The low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to claim 1, characterized in that: Also includes any one or more of the following features: C11) the flame retardant is a combination of zinc borate and magnesium hydroxide; C21) the flame retardant has a D50 particle size of less than 1.5 μm; C41) the primary antioxidant is one of hindered phenols 1010, 1076 or 330; C42) the auxiliary antioxidant is any one of thioester type DSTP, DLTP, anti-copper agent 1024 and phosphite 168, or a mixture of at least two thereof; C51) The lubricant is SR-500 from Guangzhou Yinyuan.

9. The method for preparing the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to any one of claims 1 to 8, characterized in that: The preparation method comprises: uniformly mixing ethylene-vinyl acetate copolymer, ethylene-octene copolymer and maleic anhydride grafting agent, then adding a mixture of lubricant, antioxidant, auxiliary cross-linking agent and silane coupling agent, fully mixing and then adding halogen-free flame retardant, mixing, extruding, granulating, drying and screening, and then processing into cables and then irradiating and cross-linking, with an irradiation dose of 3-10 Mrad, to obtain the low-smoke halogen-free irradiation cross-linked polyolefin insulation material for thin-walled cables.

10. Use of the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables according to any one of claims 1 to 8 and / or the low-smoke halogen-free radiation cross-linked polyolefin insulation material for thin-walled cables prepared by the preparation method according to claim 9 in the fields of building wiring and communication cables.

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