Composite cable with high insulating property and preparation method thereof

Abstract

The invention belongs to the technical field of polymer materials and electric wires and cables, and discloses a high-insulating-property composite cable and a preparation method thereof. The preparation method comprises the following steps: carrying out copolymerization reaction on hydroxyl-terminated hydrogen-containing polysiloxane, dihydric alcohol and diisocyanate to obtain an organic silicon modified polyurethane elastomer solution; then adding a vinyl cross-linking agent to carry out a cross-linking reaction, and after the reaction is completed, drying and granulating to obtain organic silicon modified polyurethane elastomer granules; uniformly mixing the elastomer granules with PE, EVA and reinforcing filler, extruding into a mold in which a metal wire is placed, coating, curing and forming to obtain an insulating layer; and finally, mixing nylon slices and color master batch, and coating the mixture on the surface of the insulating layer by injection molding for curing and forming to obtain the composite cable with high insulating property. The insulating layer adopts a specific TPE material to carry out blending modification on PE, so that the strength, the toughness and the thermal aging resistance of the insulating layer can be remarkably improved, and relatively high insulating performance can be maintained.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and electric wires and cables, and specifically relates to a high-insulation composite cable and a preparation method thereof. Background Art

[0002] The insulation materials used for cables mainly include polyvinyl chloride (PVC), polyethylene (PE), cross-linked polyethylene (XLPE), rubber, silicone rubber, etc. PVC has good insulation, chemical resistance and easy processing characteristics, but poor high temperature resistance, weather resistance and flexibility. PE has good flexibility and easy processing characteristics, but poor high temperature resistance and weather resistance. XLPE can improve the high temperature resistance and mechanical properties of PE to a certain extent, but has limited effect on improving weather resistance. Rubbers such as ethylene propylene rubber and silicone rubber have excellent aging resistance, electrical insulation and chemical resistance, but their hardness is low and their thermoplastic processing performance is poor.

[0003] Thermoplastic elastomer (TPE) has the excellent properties of high elasticity, aging resistance, and oil resistance of traditional cross-linked vulcanized rubber, and at the same time has the characteristics of convenient processing and wide processing methods of ordinary plastics. It is increasingly widely used in insulating materials such as cables. For example, the invention patent with publication number CN 117894529 A discloses a method for preparing high-toughness cables, which uses a composite material of nano-composite powder and silicone thermoplastic elastomer to coat the conductor to form an insulating layer, thereby improving the toughness and strength of the cable. However, the strength and aging resistance of the composite insulating material used need to be further improved, resulting in a decrease in the durability of cable protection and insulation stability. Summary of the invention

[0004] In view of the shortcomings and deficiencies of the above prior art, the primary purpose of the present invention is to provide a method for preparing a composite cable with high insulation performance.

[0005] Another object of the present invention is to provide a composite cable with high insulation performance prepared by the above method.

[0006] The present invention uses TPE insulation material + nylon sheath with excellent insulation performance and higher strength, which can achieve insulation performance equivalent to that of conventional PVC materials, and has higher strength and high temperature resistance. It can meet the impact protection and insulation stability under higher voltage with a lower thickness coating layer, thereby reducing the volume of the wire and reducing the cost.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a composite cable with high insulation performance comprises the following preparation steps:

[0009] (1) reacting terminal hydroxyl hydrogen-containing polysiloxane with diol and diisocyanate in an organic solvent and an organic tin catalyst to obtain an organosilicon-modified polyurethane elastomer solution; then adding a vinyl crosslinking agent and a chloroplatinic acid solution catalyst to continue the heat preservation crosslinking reaction, and drying and granulating after the reaction is completed to obtain an organosilicon-modified polyurethane elastomer pellet;

[0010] (2) adding the obtained organosilicon-modified polyurethane elastomer pellets, polyethylene (PE), ethylene-vinyl acetate copolymer (EVA) and reinforcing filler into a mixer, melting and kneading them uniformly, and then extruding them into a mold with a metal wire placed thereon, coating and curing them to obtain an insulating layer;

[0011] (3) Add nylon chips and masterbatch into an injection molding machine, heat and melt them, and then inject and coat them on the surface of the insulation layer to solidify and form them, thereby obtaining a composite cable with high insulation performance.

[0012] In the above preparation method, the terminal hydroxyl hydrogen-containing polysiloxane has the following molecular structure:

[0013] In the formula, x is an integer of 0 to 100, and y is an integer of 10 to 100. It is a common raw material in the art and can be obtained by ring-opening polymerization of hydrogen-containing cyclosiloxane or by ring-opening copolymerization of hydrogen-containing cyclosiloxane and methylcyclosiloxane.

[0014] In the above preparation method, the diol is a polyether diol (such as ethylene glycol polyether, propylene glycol polyether, etc.) or a polyester diol (such as ethylene glycol adipate diol, butylene adipate diol, polycaprolactone diol, polycarbonate diol, etc.) with a molecular weight of 500 to 3000; polyester diol is preferred. The use of polyester diol as the soft segment of the polyurethane elastomer in the present invention can further improve the strength.

[0015] In the above preparation method, the diisocyanate is one or more of 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate, and hexamethylene diisocyanate.

[0016] In the above preparation method, the organic solvent is one or more of toluene, benzene, ethyl acetate and N,N-dimethylformamide.

[0017] In the above preparation method, the molar ratio of the terminal hydroxyl hydrogen-containing polysiloxane to the diol and diisocyanate is 1:1-2:2-4.

[0018] In the above preparation method, the vinyl crosslinking agent is one or more of divinylbenzene, terminal dienes (such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, etc.), and terminal vinyl polydimethylsiloxane. Preferably, the terminal vinyl polydimethylsiloxane has a molecular weight of 1000 to 3000. The present invention uses terminal vinyl polydimethylsiloxane as a crosslinking agent for polyurethane elastomers to significantly improve the strength of the elastomer, and at the same time, the elastomer obtained by other crosslinking agents has better flexibility and heat aging resistance.

[0019] In the above preparation method, the amount of the vinyl crosslinking agent added is 5% to 40% of the mass of the terminal hydroxyl hydrogen-containing polysiloxane.

[0020] In the above preparation method, the temperature of the reaction and the heat preservation cross-linking reaction is 70 to 90° C., and the time is 2 to 6 hours.

[0021] In the above preparation method, the reinforcing filler is one or more of nano calcium carbonate, nano silicon dioxide and nano kaolin.

[0022] In the above preparation method, the mass ratio of the silicone modified polyurethane elastomer granules, PE, EVA and reinforcing fillers is: 10-40 parts of silicone modified polyurethane elastomer granules, 60-100 parts of PE, 5-20 parts of EVA, and 5-15 parts of reinforcing fillers.

[0023] A composite cable with high insulation performance is prepared by the method.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The insulating layer of the composite cable of the present invention adopts silicone-modified polyurethane elastomer to blend and modify the PE main body, which can significantly improve its strength, toughness and heat aging resistance, and can maintain high insulation performance.

[0026] (2) The present invention further cross-links the silicone-modified polyurethane elastomer, thereby further improving its strength and heat aging resistance while ensuring good toughness.

[0027] (3) By adding a certain amount of EVA to the insulating layer of the present invention, the blending modification effect of the silicone-modified polyurethane elastomer and the PE substrate can be significantly improved, thereby improving the overall performance. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0029] Example 1

[0030] A method for preparing a composite cable with high insulation performance comprises the following preparation steps:

[0031] (1) Under nitrogen protection, a terminal hydroxyl-containing hydrogenated polysiloxane (hydroxyl value 37 mgKOH / g) with a hydrogen content of 0.65 wt% and a molecular weight of 3000, a butylene adipate diol with a molecular weight of 1000 and 4,4'-diphenylmethane diisocyanate with a molar ratio of 1:1.5:3 were heated to 80°C for reaction for 3 h in a toluene solvent and an organic tin catalyst to obtain an organosilicon-modified polyurethane elastomer solution. Then, a vinyl crosslinking agent (divinylbenzene, 1,7-octadiene and a terminal vinyl-containing polydimethylsiloxane (vinyl content 2.8 wt%)) accounting for 20% of the mass of the terminal hydroxyl-containing hydrogenated polysiloxane and a chloroplatinic acid solution catalyst were added to continue the crosslinking reaction for 4 h. After the reaction was completed, the reaction was dried and granulated to obtain an organosilicon-modified polyurethane elastomer granule.

[0032] (2) adding the obtained organosilicon-modified polyurethane elastomer pellets, PE material, EVA material and nano-calcium carbonate filler in a mass ratio of 20:80:10:10 into a mixer, melting and kneading them uniformly, and then extruding them into a mold with a metal wire placed thereon, coating and curing them to obtain an insulating layer.

[0033] (3) Add nylon 66 chips and masterbatch into an injection molding machine, heat and melt them, and then inject and coat them on the surface of the insulation layer to solidify and form them, thereby obtaining a composite cable with high insulation performance.

[0034] The insulating properties (volume resistivity), tensile strength, elongation at break (GB / T 528-2009) and heat aging resistance (GB / T 7141-2008, exposure temperature of 110°C for 240 h; then tensile strength retention rate) of the insulating layer obtained in this embodiment under different vinyl crosslinking agent conditions were tested, and the insulating layer obtained by uncrosslinked silicone modified polyurethane elastomer and the insulating layer without adding silicone modified polyurethane elastomer (control group) were used for comparison. The results are shown in Table 1 below.

[0035] Table 1

[0036]

[0037]

[0038] It can be seen from the results in Table 1 that the insulating layer of the composite cable of the present invention has a high volume resistivity and excellent insulation performance. The strength and heat aging resistance of the obtained insulating layer can be significantly improved by cross-linking the organosilicon-modified polyurethane elastomer, and the insulating layer obtained by using vinyl-terminated polydimethylsiloxane as a cross-linking agent has better flexibility and heat aging resistance than other cross-linking agents.

[0039] Example 2

[0040] A method for preparing a composite cable with high insulation performance comprises the following preparation steps:

[0041] (1) Under nitrogen protection, a terminal hydroxyl-containing hydrogenated polysiloxane (hydroxyl value 37 mgKOH / g) with a hydrogen content of 0.65 wt% and a molecular weight of 3000, a butylene adipate diol with a molecular weight of 1000 and p-phenylene diisocyanate were heated to 85° C. in a molar ratio of 1:1:2 in the presence of toluene solvent and an organic tin catalyst for reaction for 4 h to obtain an organosilicon-modified polyurethane elastomer solution. Then, a vinyl crosslinking agent (a vinyl-terminated polydimethylsiloxane (vinyl content 5.6 wt%) with a molecular weight of 1000) accounting for 5% of the mass of the terminal hydroxyl-containing hydrogenated polysiloxane) and a chloroplatinic acid solution catalyst were added to continue the crosslinking reaction for 4 h at a temperature of 40 ° C. After the reaction was completed, the reaction was dried and granulated to obtain an organosilicon-modified polyurethane elastomer granule.

[0042] (2) The obtained silicone-modified polyurethane elastomer pellets, PE material, EVA material and nano-silica filler are added into a mixer in a mass ratio of 40:100:20:15, melt-mixed and uniformly kneaded, and then extruded into a mold with a metal wire placed thereon for coating and curing to obtain an insulating layer.

[0043] (3) Add nylon 66 chips and masterbatch into an injection molding machine, heat and melt them, and then inject and coat them on the surface of the insulation layer to solidify and form them, thereby obtaining a composite cable with high insulation performance.

[0044] The volume resistivity of the insulating layer obtained in this embodiment is 1.4*10 15 Ω·cm, tensile strength is 35MPa, elongation at break is 514%, and heat aging strength retention rate is 90%.

[0045] Example 3

[0046] A method for preparing a composite cable with high insulation performance comprises the following preparation steps:

[0047] (1) Under nitrogen protection, a terminal hydroxyl-containing hydrogen polysiloxane (hydroxyl value 37 mgKOH / g) with a hydrogen content of 0.65 wt% and a molecular weight of 3000, a polycarbonate diol with a molecular weight of 1000 and isophorone diisocyanate were heated to 90°C in a molar ratio of 1:2:4 in the presence of a toluene solvent and an organic tin catalyst for reaction for 2 h to obtain an organosilicon-modified polyurethane elastomer solution. Then, a vinyl crosslinking agent (a vinyl-terminated polydimethylsiloxane (vinyl content 1.9 wt%) with a molecular weight of 3000) accounting for 40% of the mass of the terminal hydroxyl-containing hydrogen polysiloxane) and a chloroplatinic acid solution catalyst were added to continue the crosslinking reaction for 4 h. After the reaction was completed, the reaction was dried and granulated to obtain an organosilicon-modified polyurethane elastomer pellet.

[0048] (2) adding the obtained organosilicon-modified polyurethane elastomer pellets, PE material, EVA material and nano-silica filler in a mass ratio of 10:60:5:5 into a mixer, melting and kneading them uniformly, and then extruding them into a mold with a metal wire placed thereon for coating and curing to obtain an insulating layer.

[0049] (3) Add nylon 66 chips and masterbatch into an injection molding machine, heat and melt them, and then inject and coat them on the surface of the insulation layer to solidify and form them, thereby obtaining a composite cable with high insulation performance.

[0050] The volume resistivity of the insulating layer obtained in this embodiment is 1.7*10 15 Ω·cm, tensile strength is 49MPa, elongation at break is 350%, and heat aging strength retention is 91%.

[0051] Example 4

[0052] A method for preparing a composite cable with high insulation performance. Compared with Example 1, propylene glycol polyether with a molecular weight of 1000 is used to replace butylene adipate diol, and the vinyl crosslinking agent is vinyl-terminated polydimethylsiloxane with a molecular weight of 2000, and the rest is the same.

[0053] The volume resistivity of the insulating layer obtained in this embodiment is 1.6*10 15 Ω·cm, tensile strength is 32MPa, elongation at break is 370%, and heat aging strength retention is 92%.

[0054] By comparing the results of this embodiment with those of embodiment 1, it can be seen that the polyester diol used as the soft segment of the polyurethane elastomer in the present invention can further improve the strength of the obtained insulating layer compared with polyether diol.

[0055] Comparative Example 1

[0056] Compared with Example 1, in this comparative example, no EVA material is added in the preparation of the insulating layer, and the vinyl crosslinking agent adopts vinyl-terminated polydimethylsiloxane with a molecular weight of 2000, and the rest is the same.

[0057] The volume resistivity of the insulating layer obtained in this embodiment is 1.5*10 15 Ω·cm, tensile strength is 34MPa, elongation at break is 338%, and heat aging strength retention is 85%.

[0058] By comparing the results of this comparative example with Example 1, it can be seen that when EVA is not added, the comprehensive performance of the insulation layer is significantly reduced. The reason is that EVA can significantly improve the blending modification effect of the silicone-modified polyurethane elastomer of the present invention and the PE substrate, thereby improving the comprehensive performance.

[0059] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite cable with high insulation performance, characterized in that: The method comprises the following preparation steps: (1) reacting terminal hydroxyl hydrogen-containing polysiloxane with diol and diisocyanate in an organic solvent and an organic tin catalyst to obtain an organosilicon-modified polyurethane elastomer solution; then adding a vinyl crosslinking agent and a chloroplatinic acid solution catalyst to continue the heat preservation crosslinking reaction, and drying and granulating after the reaction is completed to obtain an organosilicon-modified polyurethane elastomer pellet; (2) adding the obtained silicone-modified polyurethane elastomer pellets, PE, EVA and reinforcing filler into a mixer, melting and kneading them uniformly, and then extruding them into a mold with a metal wire placed thereon, coating and curing them to obtain an insulating layer; (3) Add nylon chips and masterbatch into an injection molding machine, heat and melt them, and then inject and coat them on the surface of the insulation layer to solidify and form them, thereby obtaining a composite cable with high insulation performance.

2. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The terminal hydroxyl hydrogen-containing polysiloxane has the following molecular structure: In the formula, x is an integer from 0 to 100, and y is an integer from 10 to 100.

3. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The diol is a polyether diol or polyester diol with a molecular weight of 500 to 3000; the diisocyanate is one or more of 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate and hexamethylene diisocyanate.

4. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The organic solvent is one or more of toluene, benzene, ethyl acetate and N,N-dimethylformamide.

5. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The molar ratio of the terminal hydroxyl hydrogen-containing polysiloxane to the diol and diisocyanate is 1:1-2:2-4.

6. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The vinyl crosslinking agent is one or more of divinylbenzene, terminal diene, and vinyl-terminated polydimethylsiloxane; the amount of the vinyl crosslinking agent added is 5% to 40% of the mass of the terminal hydroxyl hydrogen-containing polysiloxane.

7. The method for preparing a composite cable with high insulation performance according to claim 6, characterized in that: The vinyl crosslinking agent is vinyl-terminated polydimethylsiloxane with a molecular weight of 1000-3000.

8. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The temperature of the reaction and heat preservation cross-linking reaction is 70-90° C., and the time is 2-6 hours; the reinforcing filler is one or more of nano calcium carbonate, nano silicon dioxide, and nano kaolin.

9. The method for preparing a composite cable with high insulation performance according to claim 1, characterized in that: The mass proportion of the organic silicon modified polyurethane elastomer granules, PE, EVA and reinforcing filler is: 10-40 parts of organic silicon modified polyurethane elastomer granules, 60-100 parts of PE, 5-20 parts of EVA and 5-15 parts of reinforcing filler.

10. A high insulation performance composite cable, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

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