Halogen-free flame-retardant rubber cable material and preparation method thereof

Abstract

The present application relates to the field of flame-retardant cables, and specifically discloses a halogen-free flame-retardant rubber cable material and a preparation method thereof. A preparation method of a halogen-free flame-retardant rubber cable material comprises: S1, ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed, stirred evenly to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field; S2, infrared light irradiation treatment: after the ionized raw materials are mixed evenly with a dispersant, a lubricant and an antioxidant, they are placed in an infrared radiation device for infrared light irradiation treatment at 60-80°C; S3, mixing reaction; S4, vulcanization treatment; S5, melt hot pressing. The cable material prepared by the preparation method of the present application effectively improves the mechanical strength of the cable material while ensuring a good flame retardant effect.

Description

Technical Field

[0001] The present application relates to the field of flame-retardant cables, and more specifically, to a halogen-free flame-retardant rubber cable material and a preparation method thereof. Background Art

[0002] As an indispensable and important part of the power system, wires and cables play an irreplaceable role in daily life, commerce, and industry. With the continuous progress and development of society and the improvement of people's living standards, people pay more and more attention to safety in life. While pursuing a high-quality life, fire safety is becoming more and more important and urgent. According to reports on major fires, fires caused by spontaneous combustion of wires and cables account for a large proportion. PVC cable material is based on polyvinyl chloride resin, which is prepared by extrusion and other methods after adding other additives. Since PVC contains a large amount of chlorine, it has excellent flame retardant properties and is the main base material of cable materials. However, when PVC burns, it will produce a large amount of toxic gas, which can easily cause casualties.

[0003] As people pay more and more attention to environmental protection and life safety, how to reduce the incidence of fire and the mortality rate when fire occurs, halogen-free has become the development direction of the wire and cable industry. At present, the production of halogen-free cable materials usually no longer uses PVC materials but other halogen-free polymers, but the flame retardant properties of cable materials prepared by existing halogen-free polymers are not good. The flame retardant effect can be achieved by adding a large amount of magnesium hydroxide or other hydroxides to the halogen-free polymer matrix. However, the addition of a large amount of inorganic flame retardant materials affects the physical and mechanical properties and processing performance of the cable materials.

[0004] In summary, the existing halogen-free cable materials have the defect of being difficult to balance flame retardancy and mechanical strength during the preparation process. How to improve the mechanical strength of the cable materials while ensuring good flame retardancy has become a key issue to be urgently addressed in the current research and development of halogen-free cable materials. Summary of the invention

[0005] In order to improve the mechanical strength of cable materials while ensuring good flame retardant effects, the present application provides a halogen-free flame retardant rubber cable material and a preparation method thereof.

[0006] The present application provides a method for preparing a halogen-free flame-retardant rubber cable material using the following technical solution:

[0007] A method for preparing a halogen-free flame-retardant rubber cable material comprises the following steps:

[0008] S1. Ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed and stirred evenly to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field;

[0009] S2. Infrared light irradiation treatment: after the ionized raw material is mixed evenly with the dispersant, lubricant and antioxidant, it is placed in an infrared radiation device for infrared light irradiation treatment at 60-80°C;

[0010] S3, mixing reaction: adding the mixture treated by infrared light into a mixer, adding a flame retardant, heating to 60-80°C and stirring evenly to obtain a first cable mixture;

[0011] S4, vulcanization treatment: adding a vulcanizing agent and an accelerator to the first cable mixture in sequence for vulcanization treatment to obtain a second cable mixture;

[0012] S5. Melt hot pressing: The second cable mixture is transferred to a twin-screw extruder, and is melt-extruded to obtain a cable masterbatch. The cable masterbatch is plasticized by hot pressing, and cooled and formed to obtain a halogen-free flame-retardant rubber cable material.

[0013] Optionally, the ionization treatment conditions in S1 are a voltage of 5 kV-10 kV and a treatment time of 10 min-20 min.

[0014] Optionally, the wavelength of the infrared light in the infrared light irradiation treatment in S2 is 2.5-15 μm, the irradiation time is 15 min-30 min, and the infrared light dosage is 50-200 W / cm².

[0015] Optionally, the temperature of the vulcanization treatment in S4 is 130° C.-150° C., the pressure is 3 MPa-5 MPa, and the time is 15 min-25 min.

[0016] Optionally, the barrel temperature of the twin-screw extruder in S5 is set to 160°C-180°C, the head temperature is set to 185°C-200°C, the screw speed is 450rpm-550rpm; the hot pressing temperature is 190°C-210°C, and the pressure is 90MPa-110MPa.

[0017] Optionally, the flame retardant in S3 is a mixture of melamine polyphosphate and ammonium polyphosphate.

[0018] Optionally, the dispersant in S2 includes at least one of calcium stearate and zinc stearate.

[0019] Optionally, the vulcanizing agent in S4 is dicumyl peroxide DCP; and the accelerator is zinc oxide.

[0020] Optionally, the raw material ratio of the cable material is:

[0021] 40-50 parts of polyurethane liquid rubber;

[0022] Polyamide liquid rubber 20-30 parts;

[0023] 15-20 parts of xylene;

[0024] 6-10 parts of melamine polyphosphate;

[0025] 6-8 parts of ammonium polyphosphate;

[0026] Dicumyl peroxide DCP 5-8 parts;

[0027] Zinc oxide 2-5 parts

[0028] 1-3 parts of dispersant;

[0029] 1-3 parts of lubricant;

[0030] 1-3 parts of antioxidant.

[0031] The present application also provides a halogen-free flame-retardant rubber cable material, which is prepared by the above-mentioned preparation method.

[0032] In summary, this application has the following beneficial effects:

[0033] 1. The preparation method of the present application ionizes the rubber base material. The ionization treatment can promote the cross-linking reaction between the molecular chains of the liquid rubber to form a three-dimensional network structure, which is beneficial to improve the mechanical strength of the rubber matrix. Especially for polyurethane liquid rubber and polyamide liquid rubber, the molecular chains contain polar groups such as urethane bonds. Ionization treatment may more easily induce a cross-linking reaction, thereby forming a three-dimensional network structure with an enhanced structure; and the ionization treatment can effectively change the charge distribution on the surface of the rubber base material particles, increase the interaction force between the particles, thereby improving the uniformity and stability in the subsequent mixing and extrusion process, and thus enhancing the mechanical strength of the cable material. Infrared light irradiation treatment uses the thermal effect and vibration effect of infrared light to further treat the mixture after ionization treatment. Infrared light can penetrate the surface of the material and directly act on the inside of the material, causing the vibration and rotation of molecules or atoms, and increasing its internal energy. Under the condition of 60-80°C, infrared light irradiation promotes the interaction between the rubber base material and the additive, such as the formation of chemical bonds or the enhancement of physical adsorption, further improving the uniformity and stability of the mixture. At the same time, infrared light irradiation can also help remove moisture and volatile substances in the material, reduce the formation of bubbles and defects, and also have a positive effect on improving the mechanical strength of cable materials. In addition, infrared radiation can provide additional heat energy to promote the cross-linking reaction in the cable material, thereby enhancing the thermal stability and flame retardancy of the material.

[0034] 2. The cable material formula in this application abandons the traditional PVC material and selects halogen-free polymers such as polyurethane liquid rubber and polyamide liquid rubber as the base material. This meets the current demand for environmentally friendly materials in the wire and cable industry, reduces the risk of toxic and harmful gases produced when the cable burns, and is beneficial to protecting the environment and personnel safety. A mixture of melamine polyphosphate and ammonium polyphosphate is added to the formula as a flame retardant. These two flame retardants can form a dense carbon layer when heated, effectively isolating oxygen and heat, thereby delaying or preventing the burning of the cable. This combination can significantly improve the flame retardant properties of the cable and reduce the risk of fire. The formula also contains additives such as dispersants, lubricants, and antioxidants. These additives can further improve the processing performance and physical properties of the cable material and improve the overall mechanical strength of the cable material. DETAILED DESCRIPTION

[0035] The present application is further described in detail below with reference to the embodiments. Example

[0036] Example 1

[0037] A method for preparing a halogen-free flame-retardant rubber cable material, wherein the raw material dosage is as shown in Table 1, wherein the dispersant is calcium stearate, the lubricant is paraffin, and the antioxidant is antioxidant 264; the preparation method comprises the following steps:

[0038] S1. Ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed and stirred to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field, wherein the ionization device is set to a treatment voltage of 5 kV and a treatment time of 20 min;

[0039] S2. Infrared light irradiation treatment: after the ionized raw material is mixed evenly with the dispersant, lubricant and antioxidant, it is placed in an infrared radiation device for infrared light irradiation treatment at 60°C, wherein the wavelength of the infrared light for infrared light irradiation treatment is 2.5μm, the irradiation time is 30min, and the infrared light dose is 50W / cm²;

[0040] S3, mixing reaction: adding the mixture treated by infrared light irradiation into a mixer, and adding melamine polyphosphate and ammonium polyphosphate, heating to 60° C. and stirring evenly to obtain a first cable mixture;

[0041] S4, vulcanization treatment: adding dicumyl peroxide DCP and zinc oxide to the first cable mixture in sequence for vulcanization treatment to obtain a second cable mixture, the vulcanization temperature is 130°C, the pressure is 5MPa, and the time is 15min;

[0042] S5. Melt hot pressing: The second cable mixture is transferred to a twin-screw extruder, the barrel temperature is set to 160°C, the head temperature is set to 185°C, the screw speed is 450rpm, and the cable masterbatch is obtained through melt extrusion; the cable masterbatch is subjected to hot pressing and plasticizing treatment at a hot pressing temperature of 190°C and a pressure of 90MPa. After cooling and shaping, a halogen-free flame-retardant rubber cable material is obtained.

[0043] Example 2

[0044] A method for preparing a halogen-free flame-retardant rubber cable material, wherein the raw material dosage is as shown in Table 1, wherein the dispersant is zinc stearate, the lubricant is sodium stearate, and the antioxidant is antioxidant 168; the preparation method comprises the following steps:

[0045] S1. Ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed and stirred to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field, wherein the ionization device is set to a treatment voltage of 7 kV and a treatment time of 15 min;

[0046] S2. Infrared light irradiation treatment: after the ionized raw material is mixed evenly with the dispersant, lubricant and antioxidant, it is placed in an infrared radiation device for infrared light irradiation treatment at 70°C, wherein the wavelength of the infrared light for infrared light irradiation treatment is 7μm, the irradiation time is 25min, and the infrared light dose is 100W / cm²;

[0047] S3, mixing reaction: adding the mixture treated by infrared light irradiation into a mixer, and adding melamine polyphosphate and ammonium polyphosphate, heating to 70° C. and stirring evenly to obtain a first cable mixture;

[0048] S4, vulcanization treatment: adding dicumyl peroxide DCP and zinc oxide to the first cable mixture in sequence for vulcanization treatment to obtain a second cable mixture, the vulcanization temperature is 140°C, the pressure is 4MPa, and the time is 20min;

[0049] S5. Melt hot pressing: transfer the second cable mixture to a twin-screw extruder, set the barrel temperature to 170°C, the head temperature to 190°C, and the screw speed to 500rpm, and obtain the cable masterbatch through melt extrusion; subject the cable masterbatch to hot pressing plasticization treatment at a hot pressing temperature of 200°C and a pressure of 100MPa, and after cooling and shaping, obtain the halogen-free flame-retardant rubber cable material.

[0050] Example 3

[0051] A method for preparing a halogen-free flame-retardant rubber cable material, wherein the raw material dosage is as shown in Table 1, wherein the dispersant is zinc stearate, the lubricant is sodium stearate, and the antioxidant is antioxidant 168; the preparation method comprises the following steps:

[0052] S1. Ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed and stirred to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field, wherein the ionization device is set to a treatment voltage of 10 kV and a treatment time of 10 min;

[0053] S2. Infrared light irradiation treatment: after the ionized raw material is mixed evenly with the dispersant, lubricant and antioxidant, it is placed in an infrared radiation device for infrared light irradiation treatment at 80°C, wherein the wavelength of the infrared light for infrared light irradiation treatment is 15μm, the irradiation time is 15min, and the infrared light dose is 200W / cm²;

[0054] S3, mixing reaction: adding the mixture treated by infrared light irradiation into a mixer, and adding melamine polyphosphate and ammonium polyphosphate, heating to 80° C. and stirring evenly to obtain a first cable mixture;

[0055] S4, vulcanization treatment: adding dicumyl peroxide DCP and zinc oxide to the first cable mixture in sequence for vulcanization treatment to obtain a second cable mixture, the vulcanization temperature is 150°C, the pressure is 3MPa, and the time is 25min;

[0056] S5. Melt hot pressing: transfer the second cable mixture to a twin-screw extruder, set the barrel temperature to 180°C, the head temperature to 200°C, and the screw speed to 550rpm, and obtain the cable masterbatch through melt extrusion; subject the cable masterbatch to hot pressing plasticization treatment at a hot pressing temperature of 210°C and a pressure of 110MPa, and obtain the halogen-free flame-retardant rubber cable material after cooling and shaping.

[0057] Table 1 Amount of each raw material used in Examples 1-3 (kg)

[0058] Comparative Example

[0059] Comparative Example 1

[0060] A method for preparing a halogen-free flame-retardant rubber cable material is different from Example 3 in that: in the preparation method of this comparative example, the S1 ionization treatment step is omitted, that is, a slurry of polyurethane liquid rubber, polyamide liquid rubber and xylene is directly mixed with a dispersant, a lubricant and an antioxidant and then subjected to infrared light irradiation treatment.

[0061] Comparative Example 2

[0062] A method for preparing a halogen-free flame-retardant rubber cable material is different from Example 3 in that: in the preparation method of this comparative example, the S2 infrared light irradiation treatment step is omitted, that is, the ionized raw material is directly mixed with the dispersant, lubricant and antioxidant and then added to a mixer for mixing reaction.

[0063] Comparative Example 3

[0064] A method for preparing a halogen-free flame-retardant rubber cable material is different from Example 3 in that: in the preparation method of this comparative example, the steps S1 ionization treatment and 2 infrared light irradiation treatment are omitted, and the raw materials are directly added into a mixer for mixing reaction.

[0065] Comparative Example 4

[0066] The cable material in this comparative example is prepared according to the method of Example 1 of the application number CN201810793713.6 and the patent name A low-smoke halogen-free flame-retardant cable material and preparation method thereof.

[0067] Performance testing

[0068] The performance of the halogen-free flame-retardant rubber cable materials prepared in Examples 1-3 and Comparative Examples 1-4 was tested. The test results are shown in Table 2.

[0069] Table 2 Test results of Examples 1-3 and Comparative Examples 1-4

[0070]

[0071] The tensile strengths of Examples 1-3 are 32.5MPa, 34.5MPa, and 36.1MPa, respectively, and the elongations at break are 495%, 482%, and 493%, respectively, and the limiting oxygen index (LOI) is 55%, 58%, and 59%, respectively. These data show that the cable materials in the examples have excellent mechanical properties and flame retardant properties; compared with the cable materials in Comparative Example 4, the preparation method of the present application effectively improves the mechanical properties of the cable materials while ensuring the flame retardant properties. This is mainly due to the cross-linking effect of the ionization treatment on the molecular chains of the rubber base material, and the further optimization of the internal structure of the mixture by the infrared light irradiation treatment.

[0072] Comparison of Comparative Examples 1-3 with Example 3 shows that after omitting the ionization treatment or infrared light irradiation treatment, the tensile strength and elongation at break of the cable material are significantly reduced. The tensile strength of Comparative Example 1 (omitted ionization treatment) is 24.2MPa and the elongation at break is 405%; the tensile strength of Comparative Example 2 (omitted infrared light irradiation treatment) is lower, 22.3MPa and 412% respectively; while the tensile strength of Comparative Example 3 (both omitted) is reduced to the lowest, with a tensile strength of 23.6MPa and an elongation at break of 386%. This further verifies the key role of ionization treatment and infrared light irradiation treatment in improving the mechanical strength of cable materials.

[0073] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a halogen-free flame-retardant rubber cable material, characterized in that: The steps include: S1. Ionization treatment: polyurethane liquid rubber, polyamide liquid rubber and xylene are mixed and stirred to form a slurry, and then the slurry is placed in an ionization device for ionization treatment under the action of an electric field. The ionization treatment conditions are a voltage of 5kV-10kV and a treatment time of 10min-20min. S2. Infrared light irradiation treatment: after the ionized raw material is mixed evenly with the dispersant, lubricant and antioxidant, it is placed in an infrared radiation device for infrared light irradiation treatment at 60-80°C. The wavelength of the infrared light for infrared light irradiation treatment is 2.5-15μm, the irradiation time is 15min-30min, and the infrared light dosage is 50-200W / cm²; S3, mixing reaction: adding the mixture treated by infrared light irradiation into a mixer, adding melamine polyphosphate and ammonium polyphosphate, heating to 60-80° C. and stirring evenly to obtain a first cable mixture; S4, vulcanization treatment: adding dicumyl peroxide DCP and zinc oxide to the first cable mixture in sequence for vulcanization treatment to obtain a second cable mixture; S5, melt hot pressing: the second cable mixture is transferred to a twin-screw extruder, and is melt-extruded to obtain a cable masterbatch, and the cable masterbatch is subjected to hot pressing and plasticizing treatment, and is cooled and shaped to obtain a halogen-free flame-retardant rubber cable material; The raw material ratio of the halogen-free flame-retardant rubber cable material is: 40-50 parts of polyurethane liquid rubber; Polyamide liquid rubber 20-30 parts; 15-20 parts of xylene; 6-10 parts of melamine polyphosphate; 6-8 parts of ammonium polyphosphate; Dicumyl peroxide DCP 5-8 parts; Zinc oxide 2-5 parts 1-3 parts of dispersant; 1-3 parts of lubricant; 1-3 parts of antioxidant.

2. The method for preparing a halogen-free flame-retardant rubber cable material according to claim 1, characterized in that: The temperature of the vulcanization treatment in S4 is 130° C.-150° C., the pressure is 3 MPa-5 MPa, and the time is 15 min-25 min.

3. The method for preparing a halogen-free flame-retardant rubber cable material according to claim 1, characterized in that: The barrel temperature of the twin-screw extruder in S5 is set to 160°C-180°C, the head temperature is set to 185°C-200°C, the screw speed is 450rpm-550rpm; the hot pressing temperature is 190°C-210°C, and the pressure is 90MPa-110MPa.

4. The method for preparing a halogen-free flame-retardant rubber cable material according to claim 1, characterized in that: The dispersant in S2 includes at least one of calcium stearate and zinc stearate.

5. A halogen-free flame-retardant rubber cable material, characterized in that: The preparation method is described in any one of claims 1 to 4.

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