Flame-retardant silane crosslinked polyethylene overhead cable material and preparation method thereof

Abstract

The invention discloses a flame-retardant silane crosslinked polyethylene overhead cable material and a preparation method thereof.The insulation material is prepared from a material A and a material B according to the weight part ratio of 85: (14-16), the material A is prepared from, by weight, 65-75 parts of LLDPE resin 1, 20-25 parts of LLDPE resin 2, 4-5 parts of a processing aid, 1.9-2.1 parts of silane, 0.095-0.105 part of an initiator and 0.10-0.19 part of an antioxidant; the material B is prepared from the following raw materials in parts by weight: 1-50 parts of LLDPE resin, 1.9-2.1 parts of a catalyst, 3-5 parts of an antioxidant, 49-51 parts of carbon black master batch, 100 parts of a flame retardant and 100 parts of silicone rubber. The excellent flame-retardant effect is realized by utilizing the chemical reaction among the flame retardant, the silicon rubber and the carbon black master batch. The reaction not only improves the flame retardant property of the overhead line, but also does not affect the conventional production of the material A. Meanwhile, the flame retardant is added into the catalyst master batch, so that the extruded silane crosslinked polyethylene cable material can well pass a horizontal combustion performance test, and the safety of an overhead line is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of wire and cable materials, and in particular to a flame-retardant silane cross-linked polyethylene overhead cable material and a preparation method thereof. Background Art

[0002] In recent years, fires caused by lightning-induced fires and dripping of overhead lines are common, especially in remote areas where overhead lines are often erected on high mountains due to complex terrain. Once an overhead line is struck by lightning, it is easy to catch fire and burn, and polyethylene materials will drip during the combustion process, and these burning drippings often cause wildfires. Wildfires are extremely harmful, not only causing large-scale burning of forests, but also taking a very long time to restore to their original state. In addition, fires will burn plant resources in the forest and may even lead to the extinction of rare wild plants. At the same time, wild animals in the forest will also face threats to their survival, and soil erosion caused by fires will also affect the water quality of downstream rivers, further causing environmental problems such as air pollution.

[0003] In order to solve this problem, the industry has begun to try to replace non-flame-retardant silane cross-linked polyethylene overhead wires with flame-retardant silane cross-linked polyethylene overhead wires. However, the existing flame-retardant overhead wires often have problems such as slow extrusion speed and rough extrusion surface during the preparation process, and the flame retardant properties of some flame-retardant overhead wires cannot fully meet actual needs. Therefore, it is particularly important to develop a flame-retardant silane cross-linked polyethylene overhead wire that has excellent flame retardant properties and can meet production and use requirements. Summary of the invention

[0004] The purpose of the present invention is to meet the requirements of industry standards and the needs of market development, and to provide a flame-retardant silane cross-linked polyethylene overhead cable material and a preparation method thereof. The flame-retardant effect obtained by the chemical reaction between the flame retardant and the silicone rubber and carbon black masterbatch is added to the catalyst masterbatch, which does not affect the conventional production of material A and can also enable the silane cross-linked polyethylene cable material obtained after extrusion to have good horizontal combustion performance.

[0005] The present invention adopts the following technical solution:

[0006] A flame-retardant silane cross-linked polyethylene overhead cable material, the raw materials of which include material A and material B, wherein the weight ratio of material A to material B is 85:(14-16);

[0007] Wherein, the material A is prepared from the following raw materials in parts by weight:

[0008]

[0009] The B material is prepared from the following raw materials in parts by weight:

[0010]

[0011] Preferably, the LLDPE resin 1 added to the A material and the B material has a melt index of 2±0.2 g / 10 min at 190° C. and 2.16 kg.

[0012] More preferably, the model of the LLDPE resin 1 is Zhongmei LLDPE DFDA-7042.

[0013] Preferably, the antioxidant added to the material A and the material B is 2,2'-thiobis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0014] More preferably, the model of the LLDPE resin 2 is Zhenhai LLDPE M2320.

[0015] Preferably, the processing aid in the material A is a rheological agent FR-3, produced by Shanghai Electric International Economic and Trade Co., Ltd.

[0016] Preferably, the silane in the material A is vinyltrimethoxysilane LT-171, produced in Hubei.

[0017] Preferably, the initiator in the material A is dicumyl peroxide DCP, produced in Aksu.

[0018] Preferably, the antioxidant in the material A and the material B is 2,2'-thiobis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0019] Preferably, the catalyst in the material B is dibutyltin dilaurate.

[0020] Preferably, the carbon black masterbatch in the B material is CAB2020.

[0021] Preferably, the flame retardant in the material B is an organic phosphorus-nitrogen flame retardant.

[0022] More preferably, the flame retardant in the B material is RF770, produced by Shanghai Electric International Economic and Trade Co., Ltd.

[0023] Preferably, the silicone rubber in the material B is GM-601, produced by Shanghai Xuchuang Polymer Materials Co., Ltd.

[0024] A method for preparing a flame-retardant silane cross-linked polyethylene overhead cable material, comprising the preparation of material A, the preparation of material B, and uniformly mixing material A and material B according to a weight ratio to obtain the silane cross-linked low-smoke halogen-free flame-retardant polyolefin insulating material with a B1 flame-retardant grade;

[0025] Wherein, the preparation method of material A comprises the following steps:

[0026] S1-1, weigh various raw materials according to the formula and set aside;

[0027] S1-2, drying LLDPE resin 1 and LLDPE resin 2, adding processing aids according to the weight ratio and mixing evenly to obtain a mixture;

[0028] S1-3, adding silane, initiator and antioxidant to the mixture obtained in step S1-3 according to the weight ratio while the wall of the kneading pot is heated, mixing at high speed, and then extruding through a twin-screw extruder after mixing evenly to obtain pellet 1;

[0029] S1-4, the pellets 1 obtained in step S1-3 are sequentially dried with hot air and cold air, and then vacuum packaged to obtain material A having a water content of ≤0.2% by weight;

[0030] The preparation method of the B material comprises the following steps:

[0031] S2-1, various raw materials are weighed according to the formula and added into the internal mixer, and then the raw materials are lumped into a mass by internal mixer, and then extruded by a single screw to obtain pellet 2;

[0032] S2-2, the granular material 2 obtained in step S2-1 is sequentially dried with hot air and cold air, and then packaged to obtain material B with a moisture content of ≤0.2%.

[0033] The drying temperature of the LLDPE resin 1 and the LLDPE resin 2 is 75-85° C., and the drying time is 1.5-2.5 hours.

[0034] The heating temperature of the kneading pot wall is 45-55°C.

[0035] The rotation speed of the high-speed mixing is 475 rpm-525 rpm, and the mixing time is 2.5-3.5 minutes.

[0036] The temperatures of the twin-screw extrusion granulation zones are: 150°C in zone I, 120°C in zone II, 160°C in zone III, 160°C in zone IV, 165°C in zone V, 160°C in zone VI, 180°C in zone VII, 190°C in zone VIII, 200°C in zone IX, and 230°C in the die head zone.

[0037] In the preparation step S1-1 of material B, the temperature of each zone during the single screw extrusion granulation is: 140°C in zone I, 155°C in zone II, 165°C in zone III, 170°C in zone IV, and 175°C in zone V.

[0038] In the preparation step S1-4 of material A and the preparation step S2-2 of material B, the hot air temperature of hot air drying is 55-65°C, and the drying time is 0.5-1.5h; during cold air drying, the cold air is not heated, and the drying time is 0.51h; since the hot air takes away the moisture, the cold air reduces the material temperature of the granules and further dries them, the moisture in the cross-linked polyethylene insulation materials A and B can be removed more thoroughly, and the detected moisture content can be as low as 0.2%; the automatic dehumidification and drying equipment used when drying the granules is the DRF-25Z-KS model drying equipment of Kawada Machinery Manufacturing (Shanghai) Co., Ltd.

[0039] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0040] A. The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention utilizes the chemical reaction between the flame retardant, silicone rubber and carbon black masterbatch to achieve excellent flame retardant effect. This chemical reaction not only improves the flame retardant performance of the overhead line, but also does not affect the conventional production of material A. At the same time, by adding the flame retardant to the catalyst masterbatch, the silane cross-linked polyethylene cable material obtained after extrusion can pass the horizontal combustion performance test well, thereby ensuring the safety of the overhead line.

[0041] B. The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention has excellent characteristics such as fast extrusion speed and smooth and delicate extrusion surface, which not only improves production efficiency but also makes the overhead line more beautiful and durable during actual use.

[0042] C. The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention can not only meet the performance requirements of GB / T12527-2008 and GB / T14049-2008 standards, but also pass the horizontal combustion test, which fully proves the performance excellence and reliability of the flame-retardant silane cross-linked polyethylene overhead cable material of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is a production process flow chart of flame-retardant silane cross-linked polyethylene overhead cable material A of the present invention;

[0045] Figure 2 This is a production process flow chart of flame-retardant silane cross-linked polyethylene overhead cable material B of the present invention. DETAILED DESCRIPTION

[0046] The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0047] Example 1

[0048] Prepare material A and material B according to the following weight parts:

[0049]

[0050] A material preparation, such as Figure 1 As shown, the resin LLDPE DFDA-7042 and LLDPE M2320 are dried at 90℃*2h according to the above ratio, and then mixed with the processing aid FR-3 at a mass ratio of 97:5, and then mixed at high speed in a kneading pot heated to 50℃, and silane LT-171, initiator DCP, antioxidant 1035 are added at the same time, mixed at high speed for 3min, and then fed into a twin-screw extruder. The extrusion temperature is shown in the following table:

[0051] Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ Machine head 150 120 160 160 160 160 180 190 200 230

[0052] The extruded strips are drawn and pelletized in a water trough. The pellets are first pumped into a 60°C hot air dryer for drying for 1 hour, then pumped into a cold air dryer for drying for 1 hour, and then packed in a vacuum aluminum-plastic composite bag to obtain the required A material.

[0053] Preparation of B material, such as Figure 2 As shown, LLDPE DFDA-7042, catalyst dibutyltin dilaurate, antioxidant, carbon black masterbatch, flame retardant and silicone rubber are first added to the internal mixer and fully kneaded into a mass, and then fed into a single screw extruder. The extrusion temperature is shown in the following table:

[0054] Heating zone Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ temperature 140 155 165 170 175

[0055] After extrusion and pelletization, the particles are first pumped into a 60℃ hot air dryer for drying for 1 hour, then pumped into a cold air dryer for drying for 1 hour, and then packed in a vacuum aluminum-plastic composite bag to obtain the required B material.

[0056] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:15.

[0057] Example 2

[0058] Prepare material A and material B according to the following weight parts:

[0059]

[0060] A material preparation, such as Figure 1 As shown, the resin LLDPE DFDA-7042 and LLDPE M2320 are dried at 85℃*1.5h according to the above ratio, and then mixed with the processing aid FR-3 at a mass ratio of 85:4, and then mixed at high speed in a kneading pot heated to 45℃, and silane LT-171, initiator DCP, antioxidant 1035 are added at the same time, mixed at high speed for 3.5min, and then fed into a twin-screw extruder. The extrusion temperature is shown in the following table:

[0061] Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ Machine head 150 120 160 160 160 160 180 190 200 230

[0062] The extruded strips are drawn and pelletized in a water trough. The pellets are first pumped into a 55°C hot air dryer for drying for 1.5 hours, then pumped into a cold air dryer for drying for 1.5 hours, and then packed in a vacuum aluminum-plastic composite bag to obtain the required A material.

[0063] Preparation of B material, such as Figure 2 As shown, LLDPE DFDA-7042, catalyst dibutyltin dilaurate, antioxidant, carbon black masterbatch, flame retardant and silicone rubber are first added to the internal mixer and fully kneaded into a mass, and then fed into a single screw extruder. The extrusion temperature is shown in the following table:

[0064] Heating zone Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ temperature 140 155 165 170 175

[0065] After extrusion and pelletization, the particles are first pumped into a 55°C hot air dryer for drying for 1.5 hours, then pumped into a cold air dryer for drying for 1.5 hours, and then vacuum-packed into aluminum-plastic composite bags to obtain the required B material.

[0066] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:14.

[0067] Example 3

[0068] Prepare material A and material B according to the following weight parts:

[0069]

[0070] A material preparation, such as Figure 1 As shown, the resin LLDPE DFDA-7042 and LLDPE M2320 are dried at 75℃*2.5h according to the above ratio, and then mixed with the processing aid FR-3 at a mass ratio of 97:5, and then mixed at high speed in a kneading pot heated to 55℃, and silane LT-171, initiator DCP, antioxidant 1035 are added at the same time, mixed at high speed for 2.5min, and then fed into a twin-screw extruder. The extrusion temperature is shown in the following table:

[0071] Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ Machine head 150 120 160 160 160 160 180 190 200 230

[0072] The extruded strips are drawn and pelletized in a water trough. The pellets are first pumped into a 65°C hot air dryer for drying for 0.5 hours, then pumped into a cold air dryer for drying for 0.5 hours, and then packed in a vacuum aluminum-plastic composite bag to obtain the required A material.

[0073] Preparation of B material, such as Figure 2 As shown, LLDPE DFDA-7042, catalyst dibutyltin dilaurate, antioxidant, carbon black masterbatch, flame retardant and silicone rubber are first added to the internal mixer and fully kneaded into a mass, and then fed into a single screw extruder. The extrusion temperature is shown in the following table:

[0074] Heating zone Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ temperature 140 155 165 170 175

[0075] After extrusion and pelletization, the particles are first pumped into a 65℃ hot air dryer for drying for 0.5 hours, then pumped into a cold air dryer for drying for 0.5 hours, and then packed in a vacuum aluminum-plastic composite bag to obtain the required B material.

[0076] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:16.

[0077] Comparative Example 1

[0078] Prepare material A and material B according to the following weight parts:

[0079]

[0080] The preparation method of Comparative Example 1 is the same as that of Example 1.

[0081] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:15.

[0082] Comparative Example 2

[0083] Prepare material A and material B according to the following weight parts:

[0084]

[0085] The preparation method of Comparative Example 2 is the same as that of Example 1.

[0086] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:15.

[0087] Comparative Example 3

[0088] Prepare material A and material B according to the following weight parts:

[0089]

[0090] The preparation method of Comparative Example 2 is the same as that of Example 1, wherein the preparation of material B does not contain carbon black masterbatch.

[0091] The weight ratio of material A to material B in the flame-retardant silane cross-linked polyethylene overhead cable material is 85:15.

[0092] The material A and the material B prepared in the above Example 1 and Comparative Examples 1-3 were mixed uniformly in a weight ratio of 85:15, the material A and the material B prepared in Example 2 were mixed uniformly in a weight ratio of 85:14, and the material A and the material B prepared in Example 3 were mixed uniformly in a weight ratio of 85:16, and then extruded on a φ70 machine. The cable materials obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to surface comparison and performance tests, respectively, and their performance data are shown in Table 1.

[0093] Table 1 Performance test results of products

[0094]

[0095] From the performance data in Table 1 and the surface observation of the process test site, the surface of Examples 1-3 is smooth and delicate, and the data is quite good. Although other data of Comparative Examples 1-3 are very good, due to the wrong ratio of flame retardant to silicone rubber and even no addition of carbon black, horizontal combustion cannot be passed, and the performance of the materials in the examples cannot be achieved at the same time.

[0096] The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention utilizes the chemical reaction between the flame retardant, silicone rubber and carbon black masterbatch to achieve excellent flame retardant effect. This chemical reaction not only improves the flame retardant performance of the overhead line, but also does not affect the conventional production of material A. At the same time, by adding the flame retardant to the catalyst masterbatch, the silane cross-linked polyethylene cable material obtained after extrusion can pass the horizontal combustion performance test well, thereby ensuring the safety of the overhead line.

[0097] The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention has excellent characteristics such as fast extrusion speed and smooth and delicate extrusion surface, which not only improves production efficiency but also makes the overhead cable more beautiful and durable during actual use.

[0098] The flame-retardant silane cross-linked polyethylene overhead cable material of the present invention can not only meet the performance requirements of GB / T12527-2008 and GB / T14049-2008 standards, but also pass the horizontal combustion test, which fully proves the performance excellence and reliability of the flame-retardant silane cross-linked polyethylene overhead cable material of the present invention.

[0099] In summary, the flame-retardant silane cross-linked polyethylene overhead line of the present invention and the preparation method thereof are of great significance in solving the fire problem caused by the ignition, burning and dripping of the overhead line due to lightning strikes. It can not only improve the flame retardant properties of the overhead line, but also improve production efficiency and product quality, providing a strong guarantee for the safe development of the power industry.

[0100] Anything not described in the present invention is applicable to the prior art.

[0101] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A flame-retardant silane cross-linked polyethylene overhead cable material, characterized in that: The raw materials of the overhead cable material include material A and material B, and the weight ratio of material A to material B is 85:(14-16); Wherein, the material A is prepared from the following raw materials in parts by weight: The B material is prepared from the following raw materials in parts by weight:

2. The flame-retardant silane cross-linked polyethylene overhead cable material according to claim 1, characterized in that: The LLDPE resin 1 added to the material A and the material B has a melt index of 2±0.2 g / 10 min at 190° C. and 2.16 kg; The antioxidant is 2,2'-thiobis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

3. The flame-retardant silane cross-linked polyethylene overhead cable material according to claim 1, characterized in that: The LLDPE resin 2 added to the material A has a melt index of (8-10) g / 10 min at 150° C. and 2.16 kg; The processing aid is a rheological agent; The silane is vinyltrimethoxysilane; The initiator is dicumyl peroxide.

4. The flame-retardant silane cross-linked polyethylene overhead cable material according to claim 1, characterized in that: The catalyst added to the material B is dibutyltin dilaurate; The flame retardant is an organic phosphorus-nitrogen flame retardant.

5. A method for preparing the flame-retardant silane cross-linked polyethylene overhead cable material according to any one of claims 1 to 4, characterized in that: The method comprises the steps of preparing material A, preparing material B, and uniformly mixing material A and material B according to a weight ratio to obtain the silane cross-linked low-smoke halogen-free flame-retardant polyolefin insulating material with a flame retardant grade of B1; Wherein, the preparation method of material A comprises the following steps: S1-1, weigh various raw materials according to the formula and set aside; S1-2, drying LLDPE resin 1 and LLDPE resin 2, adding processing aids according to the weight ratio and mixing evenly to obtain a mixture; S1-3, adding silane, initiator and antioxidant to the mixture obtained in step S1-3 according to the weight ratio while the wall of the kneading pot is heated, mixing at high speed, and then extruding through a twin-screw extruder after mixing evenly to obtain pellet 1; S1-4, the pellets 1 obtained in step S1-3 are sequentially dried with hot air and cold air, and then vacuum packaged to obtain material A having a water content of ≤0.2% by weight; The preparation method of the B material comprises the following steps: S2-1, various raw materials are weighed according to the formula and added into the internal mixer, and then the raw materials are lumped into a mass by internal mixer, and then extruded by a single screw to obtain pellet 2; S2-2, the granular material 2 obtained in step S2-1 is sequentially dried with hot air and cold air, and then packaged to obtain material B with a moisture content of ≤0.2%.

6. The preparation method according to claim 5, characterized in that: In the preparation step S1-2 of material A, the drying temperature of the LLDPE resin 1 and the LLDPE resin 2 is 75-90° C., and the drying time is 1.5-2.5 h.

7. The preparation method according to claim 5, characterized in that: In the step S1-3 of preparing material A, the heating temperature of the kneading pot wall is 45-55°C.

8. The preparation method according to claim 5, characterized in that: In the preparation step S1-3 of material A, the rotation speed of the high-speed mixing is 475 rpm-525 rpm, and the mixing time is 2.5-3.5 minutes.

9. The preparation method according to claim 5, characterized in that: In the preparation step S1-3 of material A, the temperatures of each zone of the twin-screw extrusion granulation are: 150°C in zone I, 120°C in zone II, 160°C in zone III, 160°C in zone IV, 165°C in zone V, 160°C in zone VI, 180°C in zone VII, 190°C in zone VIII, 200°C in zone IX, and 230°C in the die zone.

10. The preparation method according to claim 5, characterized in that: In the preparation step S1-1 of material B, the temperature of each zone during the single screw extrusion granulation is: 140°C in zone I, 155°C in zone II, 165°C in zone III, 170°C in zone IV, and 175°C in zone V.

11. The preparation method according to claim 5, characterized in that: In the preparation step S1-4 of material A and in the preparation step S2-2 of material B, the hot air temperature of hot air drying is 55-65°C and the drying time is 0.5-1.5h; during cold air drying, the cold air is not heated and the drying time is 0.5-1h.

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