Low-smoke halogen-free flame-retardant rubber cable

Abstract

The invention relates to the technical field of cables, and provides a low-smoke halogen-free flame-retardant rubber cable which sequentially comprises an outer sheath layer, an insulating layer and a wire core from outside to inside, and the outer sheath layer comprises the following components in parts by weight: 60-70 parts of ethylene propylene diene monomer, 15-26 parts of silicone rubber, 5-10 parts of graphite, 20-30 parts of halloysite powder, 2-14 parts of polyphenyl ether, 2-6 parts of an antioxidant, 30-40 parts of a flame retardant, 2-4 parts of a vulcanizing agent and 3-5 parts of an accelerant; the silicone rubber comprises methyl phenyl vinyl silicone rubber and methyl phenyl silicone rubber, and the weight ratio of the methyl phenyl vinyl silicone rubber to the methyl phenyl silicone rubber is (1: 19)-(19: 1). According to the technical scheme, the problems of poor mechanical property and poor aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to a low-smoke, halogen-free, flame-retardant rubber cable. Background Art

[0002] Low-smoke halogen-free flame-retardant rubber cable is a cable with special properties. Its characteristic is that it produces very little smoke when burning. In contrast, ordinary cable materials such as polyvinyl chloride will release a lot of thick smoke when burning, while low-smoke halogen-free flame-retardant rubber cable can effectively reduce smoke and significantly improve the visibility of the fire scene. At the same time, the cable also has good flame retardant properties, which can effectively prevent the spread of flames and create more favorable conditions for personnel evacuation and fire rescue. In addition, the cable material does not contain halogen, which avoids the problem of toxic and harmful gases such as hydrogen halide produced when halogen burns, making it more environmentally friendly and safer.

[0003] However, compared with some traditional cable materials, rubber cable itself is relatively soft and has relatively poor mechanical properties. During the cable laying process, if it is subjected to excessive tension, the cable may be broken or the internal structure may be damaged, which will affect power transmission. In addition, as one of the main components of the cable, its molecular structure is prone to aging reactions under the action of heat and oxygen. Especially in a high temperature environment, the rubber molecular chain will gradually break, resulting in a decrease in the mechanical strength of the cable and the cable becoming harder and brittle. Therefore, the development of a low-smoke, halogen-free, flame-retardant rubber cable that has both good mechanical properties and aging resistance is of great significance to extending the service life of the cable. Summary of the invention

[0004] The invention provides a low-smoke halogen-free flame-retardant rubber cable, which solves the problems of poor mechanical properties and poor aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides a low-smoke halogen-free flame-retardant rubber cable, which comprises an outer sheath layer, an insulating layer and a core from the outside to the inside, wherein the outer sheath layer comprises the following components in parts by weight: 60-70 parts of EPDM rubber, 15-26 parts of silicone rubber, 5-10 parts of graphite, 20-30 parts of halloysite powder, 2-14 parts of polyphenylene ether, 2-6 parts of antioxidant, 30-40 parts of flame retardant, 2-4 parts of vulcanizing agent, and 3-5 parts of accelerator; The silicone rubber includes methylphenylvinyl silicone rubber and methylphenyl silicone rubber, and the weight ratio of the methylphenylvinyl silicone rubber to the methylphenyl silicone rubber is 1:19-19:1.

[0006] As a further technical solution, the weight ratio of the silicone rubber to the polyphenylene ether is 2-5:1.

[0007] When the weight ratio of silicone rubber to polyphenylene ether is 2~5:1, the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved.

[0008] As a further technical solution, the weight of the methylphenylvinyl silicone rubber is greater than the weight of the methylphenyl silicone rubber.

[0009] In the present invention, the silicone rubber includes methylphenylvinyl silicone rubber and methylphenyl silicone rubber. The two silicone rubbers with different phenyl positions are selected and compounded synergistically, which can better react with polyphenylene ether, so that the internal bonding of the outer sheath layer is denser, thereby further improving the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable. When the weight of the methylphenylvinyl silicone rubber is greater than the weight of the methylphenyl silicone rubber, the reaction between the silicone rubber and the polyphenylene ether can reach the best, thereby further improving the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable.

[0010] As a further technical solution, the halloysite powder is modified halloysite powder, and the raw materials of the modified halloysite powder include halloysite powder and a modifier; The modifier includes hydroxy aromatic ketone compounds.

[0011] In the present invention, the halloysite powder is modified by using hydroxy aromatic ketone compounds, which can improve the dispersibility of the halloysite powder in the outer sheath layer system and improve the binding effect of the halloysite powder with various components, so that the halloysite powder can be better filled in the outer sheath layer system, thereby further improving the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable.

[0012] As a further technical solution, the hydroxy aromatic ketone compound includes one or more of 2,6-dihydroxyacetophenone, 2-hydroxy-2-phenylacetophenone, and 4-hydroxybenzophenone, preferably 2-hydroxy-2-phenylacetophenone.

[0013] As a further technical solution, the weight ratio of the halloysite powder to the modifier is 24:1~4.

[0014] As a further technical solution, the preparation method of the modified halloysite powder comprises the following steps: after the halloysite powder is evenly dispersed in dimethyl sulfoxide, the modifier is added, stirred, and dried to obtain the modified halloysite powder.

[0015] As a further technical solution, the modifier further includes hydroxyapatite, and the weight ratio of the hydroxyaromatic ketone compound to the hydroxyapatite is 1-3:1.

[0016] The inventors found that when the modifier also includes hydroxyapatite, the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved by using hydroxyapatite and hydroxyaromatic ketone compounds to modify the halloysite powder. The reason may be that when hydroxyapatite exists, it not only has a good combination with the hydroxyaromatic ketone compounds, but also can act on the halloysite powder to improve the modification effect of the hydroxyaromatic ketone compounds on the halloysite powder. When the weight ratio of the hydroxyaromatic ketone compounds to hydroxyapatite in the modifier is 1 to 3:1, the modification effect can reach the best, thereby further improving the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable.

[0017] As a further technical solution, the preparation method of the modified halloysite powder comprises the following steps: A1, mixing the halloysite powder and the hydroxyapatite uniformly, grinding, and obtaining a mixture; A2. Dispersing the mixture in dimethyl sulfoxide, adding the hydroxy aromatic ketone compound, stirring, and drying to obtain the modified halloysite powder.

[0018] As a further technical solution, the particle size of the halloysite powder is 20-80 μm; the particle size of the hydroxyapatite is 20-200 nm.

[0019] As a further technical solution, the insulating layer is an EPDM rubber layer; the material of the wire core is a pure copper conductor or a copper alloy conductor.

[0020] As a further technical solution, the flame retardant is one or more of magnesium hydroxide, aluminum hydroxide, and ammonium polyphosphate.

[0021] As a further technical solution, the antioxidant is one or more of antioxidant 1076, antioxidant 626, and antioxidant 1010.

[0022] As a further technical solution, the vulcanizing agent is one or both of sulfur and diisotoluene peroxide.

[0023] As a further technical solution, the accelerator is one or more of accelerator TBBS, accelerator NS, and accelerator TMTD.

[0024] The present invention also proposes a method for preparing the low-smoke halogen-free flame-retardant rubber cable, comprising the following steps: S1, mixing the remaining components except the vulcanizing agent, adding the vulcanizing agent, mixing, extruding, and vulcanizing to obtain an outer sheath layer; S2. Cover the outer sheath layer and the insulating layer on the surface of the wire core in the order of outer sheath layer and insulating layer from outside to inside to obtain a low-smoke halogen-free flame-retardant rubber cable.

[0025] As a further technical solution, during the vulcanization, the temperature is 120-140° C. and the vulcanization time is 25-35 minutes.

[0026] The working principle and beneficial effects of the present invention are: In the present invention, rubber material is used as the main material of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable, combined with polyphenylene ether, halloysite powder, graphite and other additives, and an outer sheath layer with excellent mechanical properties and good aging resistance can be obtained, wherein the components of the outer sheath layer include silicone rubber and polyphenylene ether, and the silicone rubber includes methylphenyl vinyl silicone rubber and methylphenyl silicone rubber. The two silicone rubbers have different flexible segments, and the phenyl groups are in different positions, which can be filled in the rigid structure gap of polyphenylene ether to a certain extent, and achieve a better combination effect with polyphenylene ether. Moreover, in combination with the other components of the outer sheath layer, an outer sheath layer with a tight and stable internal structure can be constructed, thereby improving the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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.

[0028] In the following embodiments and comparative examples, the model of EPDM rubber is J-3092E; the model of methylphenylvinyl silicone rubber is MY120; the model of methylphenyl silicone rubber is SE-52; the average particle size of graphite is 74 μm; the particle size of halloysite powder is 30 μm; the particle size of hydroxyapatite is 60 nm; the model of polyphenylene ether is LXN050; the material of the core is pure copper conductor; and the insulating layer is an EPDM rubber layer.

[0029] Example 1 A low-smoke halogen-free flame-retardant rubber cable comprises an outer sheath layer, an insulating layer and a core from the outside to the inside, wherein the outer sheath layer comprises the following components in parts by weight: 60 parts of EPDM rubber, 15 parts of silicone rubber, 5 parts of graphite, 20 parts of halloysite powder, 2 parts of polyphenylene ether, 2 parts of antioxidant 626, 30 parts of magnesium hydroxide, 2 parts of sulfur, 3 parts of accelerator NS; The silicone rubber includes 0.75 parts of methylphenyl vinyl silicone rubber and 14.25 parts of methylphenyl silicone rubber; A method for preparing a low-smoke halogen-free flame-retardant rubber cable comprises the following steps: S1. Mix the remaining components except the vulcanizing agent, add sulfur, mix, extrude, and vulcanize at 120° C. for 35 minutes to obtain an outer sheath layer; S2. Cover the outer sheath layer and the insulating layer on the surface of the wire core in the order of outer sheath layer and insulating layer from outside to inside to obtain a low-smoke halogen-free flame-retardant rubber cable.

[0030] Example 2 A low-smoke halogen-free flame-retardant rubber cable comprises an outer sheath layer, an insulating layer and a core from the outside to the inside, wherein the outer sheath layer comprises the following components in parts by weight: 65 parts of EPDM rubber, 18 parts of silicone rubber, 8 parts of graphite, 24 parts of halloysite powder, 12 parts of polyphenylene ether, 4 parts of antioxidant 626, 35 parts of magnesium hydroxide, 3 parts of sulfur, 4 parts of accelerator NS; The silicone rubber includes 9 parts of methylphenyl vinyl silicone rubber and 9 parts of methylphenyl silicone rubber; A method for preparing a low-smoke halogen-free flame-retardant rubber cable comprises the following steps: S1. Mix the remaining components except the vulcanizing agent, add sulfur, mix, extrude, and vulcanize at 130° C. for 30 minutes to obtain an outer sheath layer; S2. Cover the outer sheath layer and the insulating layer on the surface of the wire core in the order of outer sheath layer and insulating layer from outside to inside to obtain a low-smoke halogen-free flame-retardant rubber cable.

[0031] Example 3 A low-smoke halogen-free flame-retardant rubber cable comprises an outer sheath layer, an insulating layer and a core from the outside to the inside, wherein the outer sheath layer comprises the following components in parts by weight: 70 parts of EPDM rubber, 26 parts of silicone rubber, 10 parts of graphite, 30 parts of halloysite powder, 14 parts of polyphenylene ether, 6 parts of antioxidant 626, 40 parts of magnesium hydroxide, 4 parts of sulfur, and 5 parts of accelerator NS; The silicone rubber includes 24.7 parts of methylphenyl vinyl silicone rubber and 1.3 parts of methylphenyl silicone rubber; A method for preparing a low-smoke halogen-free flame-retardant rubber cable comprises the following steps: S1. Mix the remaining components except the vulcanizing agent, add sulfur, mix, extrude, and vulcanize at 140° C. for 25 minutes to obtain an outer sheath layer; S2. Wrap the outer sheath layer and the insulating layer on the surface of the wire core in the order of outer sheath layer and insulating layer from outside to inside to obtain a low-smoke halogen-free flame-retardant rubber cable.

[0032] Example 4 The only difference between this embodiment and embodiment 2 is that in this embodiment, 25.6 parts of silicone rubber are added (12.8 parts of methylphenyl vinyl silicone rubber and 12.8 parts of methylphenyl silicone rubber), and 4.4 parts of polyphenylene ether are added.

[0033] Example 5 The difference between this embodiment and embodiment 2 is that, in this embodiment, 20 parts of silicone rubber are added (10 parts of methylphenyl vinyl silicone rubber and 10 parts of methylphenyl silicone rubber), and 10 parts of polyphenylene ether are added.

[0034] Example 6 The difference between this embodiment and embodiment 2 is that, in this embodiment, 25 parts of silicone rubber are added (12.5 parts of methylphenyl vinyl silicone rubber and 12.5 parts of methylphenyl silicone rubber), and 5 parts of polyphenylene ether are added.

[0035] Example 7 The only difference between this embodiment and embodiment 6 is that in this embodiment, 11 parts of methylphenyl vinyl silicone rubber are added, and 14 parts of methylphenyl silicone rubber are added.

[0036] Example 8 The only difference between this embodiment and embodiment 6 is that in this embodiment, 14 parts of methylphenyl vinyl silicone rubber are added, and 11 parts of methylphenyl silicone rubber are added.

[0037] Example 9 The only difference between this embodiment and embodiment 8 is that in this embodiment, the halloysite powder is modified halloysite powder, and its preparation method comprises the following steps: after 24 parts of halloysite powder are evenly dispersed in 80 parts of dimethyl sulfoxide, 1 part of 2-hydroxy-2-phenylacetophenone is added, stirred, and dried to obtain modified halloysite powder.

[0038] Example 10 The only difference between this embodiment and embodiment 8 is that, in this embodiment, 24 parts of halloysite powder and 4 parts of 2-hydroxy-2-phenylacetophenone are added.

[0039] Embodiment 11 The difference between this embodiment and embodiment 10 is that, in this embodiment, the halloysite powder is modified halloysite powder, and its preparation method comprises the following steps: A1. Mix 24 parts of halloysite powder and 3 parts of hydroxyapatite uniformly, grind, and obtain a mixture; A2. Disperse the mixture in 30 parts of dimethyl sulfoxide, add 1 part of 2-hydroxy-2-phenylacetophenone, stir, and dry to obtain modified halloysite powder.

[0040] Example 12 The only difference between this embodiment and embodiment 11 is that, in this embodiment, 3.5 parts of 2-hydroxy-2-phenylacetophenone and 0.5 parts of hydroxyapatite are added.

[0041] Example 13 The only difference between this embodiment and embodiment 11 is that in this embodiment, 2 parts of 2-hydroxy-2-phenylacetophenone and 2 parts of hydroxyapatite are added.

[0042] Embodiment 14 The only difference between this embodiment and embodiment 11 is that, in this embodiment, 3 parts of 2-hydroxy-2-phenylacetophenone and 1 part of hydroxyapatite are added.

[0043] Comparative Example 1 The difference between this comparative example and Example 1 is that in this comparative example, no polyphenylene ether is added, and 17 parts of silicone rubber (0.85 parts of methylphenyl vinyl silicone rubber and 16.15 parts of methylphenyl silicone rubber) are added.

[0044] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, no silicone rubber is added and 17 parts of polyphenylene ether are added.

[0045] Comparative Example 3 The only difference between this comparative example and Example 1 is that in this comparative example, silicone rubber and polyphenylene ether are not added.

[0046] Comparative Example 4 The difference between this comparative example and Example 1 is that in this comparative example, the silicone rubber is only methylphenylvinyl silicone rubber.

[0047] Comparative Example 5 The difference between this comparative example and Example 1 is that in this comparative example, the silicone rubber is only methylphenyl silicone rubber.

[0048] The outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable prepared in Examples 1 to 14 and Comparative Examples 1 to 5 was subjected to the following performance tests: ① Mechanical properties test: According to the test method in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the tensile strength and elongation at break of the outer sheath layer sample are tested, and the test speed is 500mm / min; ②Aging resistance test: After the outer sheath layer sample is subjected to an aging resistance test according to the method in GB / T 3512-2014 "Hot air accelerated aging and heat resistance test for vulcanized rubber or thermoplastic rubber", an aging resistance tensile strength test is performed, and the aging resistance tensile strength retention rate is calculated. Aging resistance tensile strength retention rate (%) = tensile strength after aging / tensile strength before aging × 100%. In the aging resistance test, the temperature is 100°C and the aging time is 288h; the result is rounded to 2 decimal places.

[0049] The test results are shown in Table 1 below: Table 1 Performance test results of the outer sheath layer of Examples 1 to 14 and Comparative Examples 1 to 5

[0050] Compared with comparative examples 1 to 5, the tensile strength before aging, the elongation at break before aging and the aging-resistant tensile strength retention rate of Example 1 are significantly improved, indicating that when the components of the outer sheath layer include silicone rubber and polyphenyl ether, and the silicone rubber includes methylphenyl vinyl silicone rubber and methylphenyl silicone rubber, the methylphenyl vinyl silicone rubber, methylphenyl silicone rubber and polyphenyl ether have a synergistic effect and can improve the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable.

[0051] Compared with Examples 2 and 4, the tensile strength before aging, the elongation at break before aging and the retention rate of tensile strength against aging of Examples 5 to 6 are improved, indicating that when the weight ratio of silicone rubber to polyphenylene ether is 2 to 5:1, the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved.

[0052] Compared with Examples 6 to 7, the tensile strength before aging, the elongation at break before aging and the aging-resistant tensile strength retention rate of Example 8 are improved, indicating that when the weight of the methylphenyl vinyl silicone rubber is greater than the weight of the methylphenyl silicone rubber, the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved.

[0053] Compared with Example 8, the tensile strength before aging, the elongation at break before aging and the aging-resistant tensile strength retention rate of Examples 9 to 10 are improved, indicating that the modification of halloysite powder with hydroxy aromatic ketone compounds can further improve the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable.

[0054] Compared with Example 10, the tensile strength before aging, the elongation at break before aging, and the retention rate of tensile strength against aging of Examples 11 to 14 are improved, indicating that the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved by modifying the halloysite powder with hydroxyapatite and hydroxyaromatic ketone compounds. Compared with Examples 11 to 12, the tensile strength before aging, the elongation at break before aging, and the retention rate of tensile strength against aging of Examples 13 to 14 are improved, indicating that when the weight ratio of the hydroxyaromatic ketone compound to hydroxyapatite in the modifier is 1 to 3:1, the mechanical properties and aging resistance of the outer sheath layer of the low-smoke halogen-free flame-retardant rubber cable can be further improved.

[0055] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. 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-smoke, halogen-free, flame-retardant rubber cable, comprising an outer sheath layer, an insulating layer and a core from the outside to the inside, characterized in that: The outer sheath layer comprises the following components in parts by weight: 60-70 parts of EPDM rubber, 15-26 parts of silicone rubber, 5-10 parts of graphite, 20-30 parts of halloysite powder, 2-14 parts of polyphenylene ether, 2-6 parts of antioxidant, 30-40 parts of flame retardant, 2-4 parts of vulcanizing agent, and 3-5 parts of accelerator; The silicone rubber includes methylphenylvinyl silicone rubber and methylphenyl silicone rubber, and the weight ratio of the methylphenylvinyl silicone rubber to the methylphenyl silicone rubber is 1:19-19:

1.

2. The low-smoke halogen-free flame-retardant rubber cable according to claim 1, characterized in that: The weight ratio of the silicone rubber to the polyphenylene ether is 2-5:

1.

3. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 1, characterized in that: The weight of the methylphenylvinyl silicone rubber is greater than the weight of the methylphenyl silicone rubber.

4. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 1, characterized in that: The halloysite powder is modified halloysite powder, and the raw materials of the modified halloysite powder include halloysite powder and a modifier; The modifier includes hydroxy aromatic ketone compounds.

5. The low-smoke halogen-free flame-retardant rubber cable according to claim 4, characterized in that: The hydroxy aromatic ketone compound includes one or more of 2,6-dihydroxyacetophenone, 2-hydroxy-2-phenylacetophenone, and 4-hydroxybenzophenone.

6. The low-smoke halogen-free flame-retardant rubber cable according to claim 4, characterized in that: The weight ratio of the halloysite powder to the modifier is 24:1-4.

7. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 4, characterized in that: The preparation method of the modified halloysite powder comprises the following steps: after the halloysite powder is evenly dispersed in dimethyl sulfoxide, the modifier is added, stirred, and dried to obtain the modified halloysite powder.

8. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 4, characterized in that: The modifier further comprises hydroxyapatite, and the weight ratio of the hydroxyaromatic ketone compound to the hydroxyapatite is 1-3:

1.

9. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 8, characterized in that: The particle size of the halloysite powder is 20-80 μm; the particle size of the hydroxyapatite is 20-200 nm.

10. The low-smoke, halogen-free, flame-retardant rubber cable according to claim 1, characterized in that: The flame retardant is one or more of magnesium hydroxide, aluminum hydroxide, and ammonium polyphosphate; and / or The antioxidant is one or more of antioxidant 1076, antioxidant 626, and antioxidant 1010; and / or The vulcanizing agent is one or both of sulfur and diisotoluene peroxide; and / or The accelerator is one or more of accelerator TBBS, accelerator NS and accelerator TMTD.

Images