Halogen-free low-smoke cable material capable of resisting low temperature of-60 DEG C

Abstract

The invention discloses a halogen-free low-smoke cable material capable of resisting a low temperature of-60 DEG C, and relates to the technical field of cable materials. The halogen-free low-smoke cable material resistant to the low temperature of-60 DEG C is prepared from the following raw materials in parts by weight: 30-60 parts of polyethylene, 80-150 parts of a flame retardant A, 10-25 parts of a flame retardant B, 30-50 parts of a vinyl acetate copolymer, 20-30 parts of an ethylene-vinyl acetate copolymer, 5-10 parts of a lubricant and 3-8 parts of a compatilizer. When the raw materials are prepared, the polyethylene, the vinyl acetate copolymer and the ethylene-vinyl acetate copolymer are mixed, so that the hardness of the cable material is reduced, the flame retardant A and the flame retardant B are added into the mixture, the flame retardance of the low-smoke halogen-free material is improved, and the limit oxygen index of the prepared cable material is higher than that of a common cable material; and meanwhile, the tensile rate tested at minus 60 DEG C is obviously improved, and the cable is not easy to break when being used in a low-temperature environment and can adapt to a more severe environment.

Description

Technical Field

[0001] The invention relates to the technical field of cable materials, in particular to a low-temperature resistant -60°C halogen-free and low-smoke cable material. Background Art

[0002] Plastics used for insulation and sheathing of wires and cables are commonly known as cable materials, which include rubber, plastic, nylon and other varieties. Almost all wire and cable products require an insulating layer except for bare wire products such as steel-core aluminum stranded wire and electromagnetic wire.

[0003] In the prior art, for example, the “halogen-free low-smoke cable material” of publication number CN105367888A includes the following components by weight: 50-80 parts of EVA40, 10-30 parts of POE, 10-20 parts of PPR, 40-60 parts of aluminum hydroxide, 30-60 parts of magnesium hydroxide, 10-30 parts of low-temperature glass powder, 5-15 parts of ZB zinc borate, and coupling agent A172. 1-3 parts, dimethyl silicone oil 5-15 parts, polyethylene wax 3-8 parts, melamine polyphosphate 3-8 parts, 8112 environmentally friendly flame retardant 5-10 parts; its preparation method comprises the following steps: (1) mixing: adding EVA40, POE, PPR in sequence → adding filler (aluminum hydroxide, magnesium hydroxide) → adding sintering shell material (low temperature glass powder, ZB zinc borate) → mixing for 1-3 minutes → adding auxiliary agents (dimethyl silicone oil, coupling agent A172, polyethylene wax, melamine polyphosphate and 8112 environmentally friendly flame retardant) → mixing for 3-5 minutes → feeding; (2) granulation: conveying the above-mentioned feeding to a double-stage granulation equipment for extrusion → rotary granulation → three-stage air conveying → screening → packaging.

[0004] However, in the prior art, the existing low-smoke halogen-free cable materials have high surface hardness, relatively low flexibility at room temperature, and are prone to hardening and cracking. When the material is used in a low temperature environment, especially at a temperature of minus 60°C, the cable material's elongation at break and resistance to low-temperature cracking will further deteriorate, causing the cable to crack easily or even become brittle, and unable to meet the material's use standards.

[0005] Therefore, we proposed a low-temperature resistant -60℃ halogen-free and low-smoke cable material to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a low-temperature resistant -60°C halogen-free and low-smoke cable material, so as to solve the problem that the existing cable material proposed in the above background technology is used in a low-temperature environment, especially when the temperature is minus 60°C, the elongation at break and the low-temperature cracking resistance of the cable material will further deteriorate, resulting in the cable being easy to crack or even brittle, and unable to meet the material use standards. By mixing polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer, it is beneficial to improve the interaction between inorganic particles and the matrix, alleviate the agglomeration problem of inorganic flame retardant particles, and reduce the hardness of the cable material. Flame retardant A and flame retardant B are added to the mixture to improve the flame retardancy of the low-smoke halogen-free material. While having excellent flame retardant properties, it has the benefits of good stability and non-toxic smoke, thereby improving the practical application value of the cable material. The prepared cable material has a limiting oxygen index higher than that of general cable materials, and at the same time, the elongation tested at minus 60°C is significantly improved, which is 20% higher than the standard. The cable material has higher low-temperature resistance, can be used in a low-temperature environment without being easily broken, and can adapt to more severe environments.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a low-temperature resistant -60°C halogen-free and low-smoke cable material, which is made of the following raw materials in parts by weight: 30-60 parts of polyethylene, 80-150 parts of flame retardant A, 10-25 parts of flame retardant B, 30-50 parts of vinyl acetate copolymer, 20-30 parts of ethylene-vinyl acetate copolymer, 5-10 parts of lubricant, and 3-8 parts of compatibilizer.

[0008] A preparation method is also used, comprising the following steps: S1. Raw material preparation: weigh each component raw material according to the formula ratio, and send the weighed polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for 12 hours to remove moisture; S2, mixing roll: put the dried polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer in an open mill, fully mix the flame retardant A, flame retardant B, lubricant and compatibilizer, add them into the open mill, and melt shear mix for 15 minutes; S3, blend treatment: preheating the mixed blend and feeding it into an extruder, extruding the blend into strips, and obtaining pellets after cooling and crushing; S4. Preparation of cable materials: The screened particles are placed in a vacuum flat vulcanizer, and molded for 10 minutes at a temperature of 150°C and a pressure of 8 MPa to obtain the material. Subsequently, a slicer is used to punch the material into cylindrical particles with a diameter of 4 mm. The particles are placed in a vacuum drying oven and dried for 12 hours to obtain the prepared cable material.

[0009] Preferably, in step S1, the temperature of the vacuum drying oven for drying polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer is set to 60-80°C.

[0010] Preferably, in step S2, the rotation speed of the mixing mill is set to 120 r / min.

[0011] Preferably, in step S3, the preheating temperature of the blend is set to 150-180°C.

[0012] Preferably, in step S3, the blend treatment further comprises the following steps: S31, preheating the mixed blend for 8 minutes, and feeding the treated blend into the barrel of an extruder; S32, the blend is pushed by the pressure screw and extruded out of the extruder to form a strip, and the extruded strip is quickly cooled and solidified into a solid state by cooling water; S33, the cooled and solidified strips are sent to a crusher and crushed into particles; S34, screening the crushed particles, screening out the particles that do not meet the set range, and screening out the particles of qualified size.

[0013] Preferably, in step S32, the screw temperature of the extruder is set to 120°C.

[0014] Preferably, in step S4, the temperature of the vacuum drying oven for drying the pellets is set to 40-50°C.

[0015] Compared with the prior art, the present invention has the following beneficial effects: During the preparation of raw materials, the present invention mixes polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer, which is beneficial to improving the interaction between inorganic particles and the matrix, alleviating the agglomeration problem of inorganic flame retardant particles, reducing the hardness of the cable material, adding flame retardant A and flame retardant B to the mixture, improving the flame retardancy of the low-smoke halogen-free material, and having the benefits of good stability and non-toxic smoke while having excellent flame retardancy, thereby improving the practical application value of the cable material, adding compatibilizer RD360 to make organic materials and inorganic materials compatible, adding lubricant PE wax to play a bridging role between different materials, so that the whole system is better integrated, and the prepared cable material has a limiting oxygen index higher than that of general cable materials, that is, the cable material has better flame retardancy, and at the same time, the elongation tested at minus 60°C is significantly improved, which is 20% higher than the standard, and the cable material has higher low-temperature resistance, can be used in a low-temperature environment without being easily broken, and can adapt to a more severe environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a flow chart of a low-temperature-resistant -60°C halogen-free and low-smoke cable material of the present invention; Figure 2 The -60°C elongation bar graph of a -60°C low-temperature resistant halogen-free and low-smoke cable material according to the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0018] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, which is made of the following raw materials in parts by weight: 30 parts of polyethylene, 80 parts of flame retardant A, 10 parts of flame retardant B, 30 parts of vinyl acetate copolymer, 20 parts of ethylene-vinyl acetate copolymer, 5 parts of lubricant, and 3 parts of compatibilizer.

[0019] Wherein, flame retardant A is magnesium hydroxide 10FG, flame retardant B is magnesium hydroxide H5, the model of vinyl acetate copolymer is EVM500, the model of ethylene-vinyl acetate copolymer is 40LX, the lubricant is PE wax, and the model of compatibilizer is RD360.

[0020] A preparation method is also used, comprising the following steps: Step 1, raw material preparation: weigh each component raw material according to the formula ratio, send the weighed polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for 12 hours to remove moisture, so as to avoid moisture volatilization and bubble generation in the subsequent molding process, resulting in material defects; The temperature of the vacuum drying oven for drying polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer is set at 60°C; Step 2, mixing roll: Place the dried polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer in an open mill, fully mix the flame retardant A, flame retardant B, lubricant and compatibilizer, add them into the open mill, and melt shear mix for 15 minutes; Among them, the speed of the mixing mill is set to 110r / min; Step 3, blend treatment: preheat the mixed blend and feed it into an extruder, extrude the blend into strips, and obtain pellets after cooling and crushing; The preheating temperature of the blend was set at 150°C, and the screw temperature of the extruder was set at 120°C; The blend processing also includes the following steps: 31. Preheat the mixed blend for 8 minutes, and feed the mixed blend into the barrel of the extruder; 32. The blend is pushed by the pressure screw and extruded out of the extruder to form a strip. The extruded strip is quickly cooled and solidified into a solid state by cooling water. 33. The cooled and solidified strips are sent to the crusher to be crushed into particles; 34. Screen the broken particles, filter out the particles that do not meet the set range, and screen out the particles of qualified size.

[0021] Step 4, preparation of cable material: placing the crushed granules in a vacuum flat vulcanizer, molding for 10 min at a temperature of 150° C. and a pressure of 8 MPa to prepare the material, then using a slicer to punch the material into cylindrical granules with a diameter of 4 mm, placing the granules in a vacuum drying oven and drying them for 12 h to obtain the prepared cable material; The temperature of the vacuum drying oven for drying the pellets was set at 40°C. Embodiment 2

[0022] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, which is made of the following raw materials in parts by weight: 45 parts of polyethylene, 115 parts of flame retardant A, 20 parts of flame retardant B, 40 parts of vinyl acetate copolymer, 25 parts of ethylene-vinyl acetate copolymer, 8 parts of lubricant, and 5 parts of compatibilizer.

[0023] Wherein, flame retardant A is magnesium hydroxide 10FG, flame retardant B is magnesium hydroxide H5, the model of vinyl acetate copolymer is EVM500, the model of ethylene-vinyl acetate copolymer is 40LX, the lubricant is PE wax, and the model of compatibilizer is RD360.

[0024] A preparation method is also used, comprising the following steps: Step 1, raw material preparation: weigh each component raw material according to the formula ratio, send the weighed polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for 12 hours to remove moisture, so as to avoid moisture volatilization and bubble generation in the subsequent molding process, resulting in material defects; The temperature of the vacuum drying oven for drying polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer is set at 70°C; Step 2, mixing roll: Place the dried polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer in an open mill, fully mix the flame retardant A, flame retardant B, lubricant and compatibilizer, add them into the open mill, and melt shear mix for 15 minutes; Among them, the speed of the mixing mill is set to 120r / min; Step 3, blend treatment: preheat the mixed blend and feed it into an extruder, extrude the blend into strips, and obtain pellets after cooling and crushing; The preheating temperature of the blend was set at 165°C, and the screw temperature of the extruder was set at 120°C; The blend processing also includes the following steps: 31. Preheat the mixed blend for 8 minutes, and feed the mixed blend into the barrel of the extruder; 32. The blend is pushed by the pressure screw and extruded out of the extruder to form a strip. The extruded strip is quickly cooled and solidified into a solid state by cooling water. 33. The cooled and solidified strips are sent to the crusher to be crushed into particles; 34. Screen the broken particles, filter out the particles that do not meet the set range, and screen out the particles of qualified size.

[0025] Step 4, preparation of cable material: placing the crushed granules in a vacuum flat vulcanizer, molding for 10 min at a temperature of 150° C. and a pressure of 8 MPa to prepare the material, then using a slicer to punch the material into cylindrical granules with a diameter of 4 mm, placing the granules in a vacuum drying oven and drying them for 12 h to obtain the prepared cable material; The temperature of the vacuum drying oven for drying the pellets was set at 45°C. Embodiment 3

[0026] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, which is made of the following raw materials in parts by weight: 60 parts of polyethylene, 150 parts of flame retardant A, 25 parts of flame retardant B, 50 parts of vinyl acetate copolymer, 30 parts of ethylene-vinyl acetate copolymer, 10 parts of lubricant, and 8 parts of compatibilizer.

[0027] Wherein, flame retardant A is magnesium hydroxide 10FG, flame retardant B is magnesium hydroxide H5, the model of vinyl acetate copolymer is EVM500, the model of ethylene-vinyl acetate copolymer is 40LX, the lubricant is PE wax, and the model of compatibilizer is RD360.

[0028] A preparation method is also used, comprising the following steps: Step 1, raw material preparation: weigh each component raw material according to the formula ratio, send the weighed polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for 12 hours to remove moisture, so as to avoid moisture volatilization and bubble generation in the subsequent molding process, resulting in material defects; The temperature of the vacuum drying oven for drying polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer is set at 80°C; Step 2, mixing roll: Place the dried polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer in an open mill, fully mix the flame retardant A, flame retardant B, lubricant and compatibilizer, add them into the open mill, and melt shear mix for 15 minutes; Among them, the speed of the mixing mill is set to 130r / min; Step 3, blend treatment: preheat the mixed blend and feed it into an extruder, extrude the blend into strips, and obtain pellets after cooling and crushing; The preheating temperature of the blend was set at 180°C, and the screw temperature of the extruder was set at 120°C; The blend processing also includes the following steps: 31. Preheat the mixed blend for 8 minutes, and feed the mixed blend into the barrel of the extruder; 32. The blend is pushed by the pressure screw and extruded out of the extruder to form a strip. The extruded strip is quickly cooled and solidified into a solid state by cooling water. 33. The cooled and solidified strips are sent to the crusher to be crushed into particles; 34. Screen the broken particles, filter out the particles that do not meet the set range, and screen out the particles of qualified size.

[0029] Step 4, preparation of cable material: placing the crushed granules in a vacuum flat vulcanizer, molding for 10 min at a temperature of 150° C. and a pressure of 8 MPa to prepare the material, then using a slicer to punch the material into cylindrical granules with a diameter of 4 mm, placing the granules in a vacuum drying oven and drying them for 12 h to obtain the prepared cable material; The temperature of the vacuum drying oven for drying the pellets was set at 50°C. Comparative Example 1

[0030] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, and its preparation method is roughly the same as that of Example 1, with the main difference being that in step 1, when the raw materials are prepared, the polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer are not sent to a vacuum drying oven for drying. Comparative Example 2

[0031] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, and its preparation method is roughly the same as that of Example 1, with the main difference being that in step 2, no flame retardant B is added during mixing and rolling. Comparative Example 3

[0032] Please refer to Figure 1-2 As shown, this embodiment provides a low-temperature resistant -60°C halogen-free and low-smoke cable material, and its preparation method is roughly the same as that of the first embodiment, with the main difference being that in step four, the pressure of the vacuum flat vulcanizer is set to 3MPa. Test Trial:

[0033] The cable materials prepared by Examples 1, 2 and 3 are recorded as Example Groups 1-3, and the cable materials prepared by Comparative Examples 1-3 are recorded as Comparative Groups 1-3. According to GB / T2406-2008 and GB / T2951.5-1997 standards, the limiting oxygen index and elongation at -60°C of the cable materials of Example Groups 1-3 and Comparative Groups 1-3 are tested, and the relevant test data are recorded in Table 1. Table 1: Test data record table

[0034] Group Limiting oxygen index (%) -60℃ elongation (%) Example 1 Group 26.1 28 Example 2 Group 26.3 30 Example 3 Group 26.5 26 Comparison group 1 24.5 15 Comparison of 2 groups 24.2 23 Comparison of 3 groups 25.5 17 As can be seen from Table 1, the cable materials prepared by example groups 1-3 have a limiting oxygen index higher than 26%, and an elongation greater than 25% at -60°C, which is higher than the standard of 20%. They have passed the -60°C low-temperature impact test, which means that the cable materials prepared by implementation groups 1-3 have higher low-temperature resistance, can be used in low-temperature environments without breaking, and can adapt to more severe environments.

[0035] In comparison group 1, when preparing the raw materials, polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer were not sent to the vacuum drying oven for drying, resulting in hollowing inside the prepared cable material, making the measured limiting oxygen index value and the elongation tested at -60°C significantly lower than those of the other groups. In comparison group 2, only flame retardant A was added without flame retardant B, and the limiting oxygen index of the cable material test decreased significantly. In comparison group 3, the working pressure of the vacuum flat vulcanizer was reduced, resulting in a decrease in the elongation value of the cable material tested at -60°C. The molding pressure will affect the elongation of the cable material. When preparing the raw materials, the present invention first puts polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for drying for 12 hours to remove moisture, so as to avoid volatilization of moisture in the subsequent molding process to generate bubbles and cause material defects. By adding vinyl acetate copolymer and ethylene-vinyl acetate copolymer, it is beneficial to improve the interaction between inorganic particles and the matrix, alleviate the agglomeration problem of inorganic flame retardant particles, and reduce the hardness of the cable material. By adding flame retardant A and flame retardant B, the flame retardancy of the low-smoke halogen-free material is improved. While having excellent flame retardant performance, it has the benefits of good stability and non-toxic smoke, thereby improving the practical application value of the cable material. The added compatibilizer RD360 can The organic material and the inorganic material are made compatible, and the added lubricant PE wax can act as a bridge between different materials, so that the whole system is better integrated. After the pellets are prepared, they are sent into a vacuum dryer for drying for 12 hours to finally obtain a cable material, which can improve the dryness of the pellets. The prepared cable material has a limiting oxygen index higher than that of ordinary cable materials, that is, the cable material prepared by the present invention has good flame retardancy. At the same time, the elongation tested at minus 60°C is significantly improved, which is 20% higher than the standard. The cable material has higher low-temperature resistance, can be used in a low-temperature environment without being easily broken, can adapt to a more severe environment, and reduces the possibility of cracking and brittleness of the cable material when used in a low-temperature environment.

[0036] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-temperature resistant -60℃ halogen-free low-smoke cable material, characterized by: The invention is prepared from the following raw materials in parts by weight: 30-60 parts of polyethylene, 80-150 parts of flame retardant A, 10-25 parts of flame retardant B, 30-50 parts of vinyl acetate copolymer, 20-30 parts of ethylene-vinyl acetate copolymer, 5-10 parts of lubricant and 3-8 parts of compatibilizer.

2. According to the low temperature resistant -60℃ halogen-free low smoke cable material as described in claim 1, characterized in that: A preparation method is also used, comprising the following steps: S1. Raw material preparation: weigh each component raw material according to the formula ratio, and send the weighed polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer into a vacuum drying oven for 12 hours to remove moisture; S2, mixing roll: put the dried polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer in an open mill, fully mix the flame retardant A, flame retardant B, lubricant and compatibilizer, add them into the open mill, and melt shear mix for 15 minutes; S3, blend treatment: preheating the mixed blend and feeding it into an extruder, extruding the blend into strips, and obtaining pellets after cooling and crushing; S4. Preparation of cable materials: The screened particles are placed in a vacuum flat vulcanizer, and molded for 10 minutes at a temperature of 150°C and a pressure of 8 MPa to obtain the material. Subsequently, a slicer is used to punch the material into cylindrical particles with a diameter of 4 mm. The particles are placed in a vacuum drying oven and dried for 12 hours to obtain the prepared cable material.

3. According to the low temperature resistant -60℃ halogen-free low smoke cable material as described in claim 2, it is characterized by: In step S1, the temperature of the vacuum drying oven for drying polyethylene, vinyl acetate copolymer and ethylene-vinyl acetate copolymer is set to 60-80°C.

4. According to the low temperature resistant -60℃ halogen-free low smoke cable material as described in claim 2, characterized in that: In step S2, the rotation speed of the mixing mill is set to 110-130 r / min.

5. According to the low temperature resistant -60℃ halogen-free low smoke cable material as described in claim 2, it is characterized by: In step S3, the preheating temperature of the blend is set to 150-180°C.

6. According to claim 2, a low-temperature-resistant -60°C halogen-free low-smoke cable material, characterized in that: In step S3, the blend treatment further comprises the following steps: S31, preheating the mixed blend for 8 minutes, and feeding the treated blend into the barrel of an extruder; S32, the blend is pushed by the pressure screw and extruded out of the extruder to form a strip, and the extruded strip is quickly cooled and solidified into a solid state by cooling water; S33, the cooled and solidified strips are sent to a crusher and crushed into particles; S34, screening the crushed particles, screening out the particles that do not meet the set range, and screening out the particles of qualified size.

7. The low-temperature-resistant -60°C halogen-free and low-smoke cable material according to claim 6, characterized in that: In step S32, the screw temperature of the extruder is set to 120°C.

8. According to claim 2, a low-temperature-resistant -60°C halogen-free low-smoke cable material, characterized in that: The temperature of the vacuum drying oven for drying the pellets is set at 40-50°C.

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