Low-smoke halogen-free flame-retardant cable and manufacturing method thereof

[0050] Example 1 Preparation and performance of cable insulation layer

[0051] Raw material: The components and weight ratio of the outer layer are: linear low density polyethylene: magnesium hydroxide: montmorillonite = 45:50:5;

[0052] The composition and weight ratio of the intermediate layer are: linear low density polyethylene: vinyl trimethoxysilane: dicumyl peroxide: dibutyl tin dilaurate: stearic acid + zinc oxide = 95.4:1:0.1: 0.5:3;

[0053] The composition and weight ratio of the inner layer are: linear low-density polyethylene: vinyltrimethoxysilane: dicumyl peroxide: dibutyltin dilaurate: alkyl sulfonic acid + tin oxide = 95.3: 2: 0.2 :1:1.5;

[0054] Among them, the grade of linear low density polyethylene is 218W.

[0055] Preparation method: Weigh various raw materials according to the above ratio. The middle layer and the innermost layer are processed in the form of A\B material, that is, polyolefin resin base material (in this example, linear low-density polyethylene) is mixed with silane and peroxide and then pelletized to make A material , Then the polyolefin resin base material, the crosslinking catalyst, and the water producing agent are mixed and pelletized to form the B material, and then the A material and the B material are mixed and extruded in a certain ratio (such as 19:1); for the outermost layer directly Than mixed. Three extruders are used to extrude the cable insulation layer by a multi-layer co-extrusion device and coat it on the cable core through a co-extrusion die; wherein, by controlling the distribution ratio of each layer of the multi-layer co-extrusion device, the obtained The thickness of each layer of the cable insulation layer is: outer layer thickness 0.5mm, middle layer thickness 0.2mm, and inner layer thickness 0.3mm.

[0056] Performance of cable insulation layer: The pH weighted value of the combustion product of the cable insulation layer is 6.2, and the light transmittance of smoke and dust generated during combustion is 81.5%. Both single burning and bundle burning meet the requirements of GB/T18380; the tensile strength of the cable insulation layer It is 18.5MPa, and the elongation at break is 520%; the cable insulation layer can withstand 10kV high voltage.

[0057] Example 2 Preparation and performance of cable insulation layer

[0058] Raw material: the components and weight ratio of the outer layer are: low density polyethylene: polyphosphate amine: pentaerythritol: montmorillonite = 67:20:10:3;

[0059] The composition and weight ratio of the intermediate layer are: low density polyethylene: vinyl triethoxy silane: benzoyl peroxide: stannous octoate: magnesium hydroxide = 93.5:1:0.5:1:4;

[0060] The composition and weight ratio of the inner layer are: low-density polyethylene: vinyl triethoxy silane: benzoyl peroxide: organic titanium chelate: alkyl sulfonic acid + tin oxide = 94.5: 2: 0.5: 2:1;

[0061] Among them, the low-density polyethylene brand name is DJ210.

[0062] Preparation method: same as Example 1, by controlling the distribution ratio of each layer of the multi-layer co-extrusion device, the thickness of each layer of the obtained cable insulation layer is: the thickness of the outer layer is 0.3 mm, the thickness of the middle layer is 0.1 mm, and the thickness of the inner layer is 0.2 mm.

[0063] Cable insulation layer performance: the weighted PH value of the combustion product of the cable insulation layer is 5.7, the smoke and dust generated during combustion have a light transmittance of 85.1%, and the single burning and bundle burning meet the requirements of GB/T18380; the tensile strength of the cable insulation layer It is 17.4MPa and the elongation at break is 530%; the cable insulation layer can withstand 3kV high voltage.

[0064] Example 3 Preparation and performance of cable insulation layer

[0065] Raw material: The components and weight ratio of the outer layer are: low density polyethylene: aluminum hydroxide: montmorillonite = 47:50:3;

[0066] The composition and weight ratio of the intermediate layer are: low-density polyethylene: vinyltrimethoxysilane: 1,1-di-tert-butylperoxycyclohexane: tetraphenyltin: magnesium hydroxide = 94:1: 0.5:1:3.5;

[0067] The composition and weight ratio of the inner layer are: low density polyethylene: vinyl triethoxy silane: benzoyl peroxide: alkylbenzene sulfonic acid: benzene sulfonic acid + zinc oxide = 94.5: 2: 0.2: 2 ︰1;

[0068] Among them, the low-density polyethylene grade is QLT17.

[0069] Preparation method: same as Example 1, by controlling the distribution ratio of each layer of the multi-layer co-extrusion device, the thickness of each layer of the obtained cable insulation layer is: the thickness of the outer layer is 1.0 mm, the thickness of the middle layer is 0.5 mm, and the thickness of the inner layer is 1.0 mm.

[0070] Cable insulation layer performance: the PH weighted value of the combustion product of the cable insulation layer is 6.1, the smoke and dust generated during combustion have a light transmittance of 75%, and the single burning and bundle burning meet the requirements of GB/T18380; the tensile strength of the cable insulation layer It is 18.9MPa and the elongation at break is 490%; the cable insulation layer can withstand 35kV high voltage.