Low-smoke halogen-free flame-retardant cable material and preparation method thereof

Abstract

The invention relates to a low-smoke halogen-free flame-retardant cable material and a preparation method thereof, and belongs to the technical field of high polymer materials, the low-smoke halogen-free flame-retardant cable material comprises the following raw materials by weight: 30-40 parts of polyethylene resin; 5 to 10 parts of silane modified polyether resin; 5-10 parts of a compatilizer; 40 to 50 parts of a flame retardant; 1 part of an antioxidant; 1 part of carbon black master batch; and 1 part of silicone. According to the low-smoke halogen-free flame-retardant cable material, the problems that a traditional halogen-free flame-retardant polyolefin material is poor in fluidity and difficult in injection molding are solved, the light transmittance is improved, other necessary electrical performance is considered, breakthrough in the injection molding process is achieved, and the safety and reliability of a pre-branched cable are improved.

Description

Technical Field

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

[0002] Prefabricated branch cables are mainly designed and manufactured from main cables, branch lines and branch connectors. The main cables and branch lines use flame-retardant polyolefin materials as the insulation or sheath materials of the cables, and the branch connectors should also use halogen-free low-smoke flame-retardant polyolefin materials from the performance requirements. Otherwise, when installing and laying at the construction site, gaps will appear at the joints bonded together, resulting in serious quality problems.

[0003] However, in practical applications, especially in the injection molding process of pre-branching cable connectors, the poor fluidity of low-smoke halogen-free flame-retardant polyolefin materials has become a common problem faced by the industry. Although the existing halogen-free low-smoke flame-retardant polyolefin materials can meet the basic flame retardant requirements, the poor fluidity makes it difficult to guarantee the quality of injection molded parts, especially the connection parts are prone to form air gaps, which reduces the overall performance of the pre-branching cable.

[0004] Therefore, there is an urgent need to develop a low-smoke halogen-free flame-retardant cable material with improved fluidity and light transmittance. Summary of the invention

[0005] The present application provides a low-smoke halogen-free flame-retardant cable material and a preparation method thereof, which solves the problems of poor fluidity and difficulty in injection molding of traditional halogen-free flame-retardant polyolefin materials, improves the light transmittance while taking into account other necessary electrical properties, achieves a breakthrough in the injection molding process, and improves the safety and reliability of pre-branching cables.

[0006] The first aspect of the present application provides a low-smoke halogen-free flame-retardant cable material, wherein the raw materials for preparing the cable material include, by weight: 30-40 parts of polyethylene resin; Silane modified polyether resin 5-10 parts; Compatibilizer 5-10 parts; Flame retardant 40-50 parts; 1 part antioxidant; 1 part of carbon black masterbatch; 1 part silicone.

[0007] By adopting the above technical scheme, the addition of silane-modified polyether resin can reduce the crystallinity of polyethylene resin, thereby reducing light scattering caused by crystalline areas and improving light transmittance; the polar groups of silane-modified polyether resin can improve the interface compatibility between polymer and filler or other additives, reduce interface defects, and thus reduce light scattering; by reducing light scattering, improving interface compatibility and reducing crystallinity, silane-modified polyether resin can effectively improve the light transmittance of cable materials.

[0008] Optionally, the polyethylene resin is selected from one or more of low-density polyethylene resin, linear low-density polyethylene resin, and metallocene linear low-density polyethylene resin.

[0009] Optionally, the silane-modified polyether resin is selected from one or more of Jiangsu Ruiyang Antai 200D and SAX260.

[0010] Optionally, the compatibilizer is selected from one or more of polyethylene glycol grafted polyethyleneimine and maleic anhydride grafted polyethylene.

[0011] By adopting the above technical scheme, the flexibility and low melt viscosity of the polyethylene glycol chain segment can reduce the friction between polyethylene molecular chains and improve the fluidity of the material; the synergistic effect of polyethylene glycol grafted polyethyleneimine and maleic anhydride grafted polyethylene significantly improves the fluidity of the cable material through the dual mechanisms of plasticization and interface lubrication. The two work together to improve the dispersion and interface compatibility of the filler, making the material more uniform and significantly improving the light transmittance.

[0012] Optionally, the antioxidant is selected from one or more of phenolic antioxidants, phosphite antioxidants, and thioester antioxidants.

[0013] By adopting the above technical solution, antioxidants are used to prevent the material from degrading at high temperatures, thereby ensuring the long-term stability and electrical properties of the material.

[0014] Optionally, the flame retardant is selected from one or more of magnesium hydroxide, highly flame-retardant red phosphorus and antimony trioxide.

[0015] By adopting the above technical solution, magnesium hydroxide, highly flame-retardant red phosphorus and antimony trioxide work synergistically to improve the flame retardant properties of the material.

[0016] The second aspect of the present application provides a method for preparing a low-smoke halogen-free flame-retardant cable material as described above, comprising the following steps: Step 1: polyethylene resin, silane-modified polyether resin, flame retardant, carbon black masterbatch, and antioxidant are mixed evenly, and a compatibilizer and silicone are added, and the mixture is continuously mixed to obtain a mixture; Step 2: sending the mixture into a screw extruder for extrusion and granulation to obtain the cable material.

[0017] The third aspect of the present application provides the use of the low-smoke halogen-free flame-retardant cable material as described above for preparing a branch connector of a branch cable.

[0018] In summary, the present application includes at least one of the following beneficial technical effects: This application significantly improves the fluidity of low-smoke halogen-free flame-retardant cable materials, making the materials more suitable for the injection molding process of pre-branching cable connectors, reducing the air gap phenomenon at the connection parts, and improving the safety and reliability of the cables; The light transmittance of the material in this application reaches more than 80%, which is much higher than the general performance of similar products, providing a strong guarantee for unobstructed vision in emergency situations such as fire; This application successfully achieved a balance between high light transmittance and other necessary properties (such as flame retardancy and mechanical strength) by optimizing the formula, meeting the material performance requirements of "JB / T10436-2006 Rated voltage 0.6 / 1kv (Um=1.2kv) copper core plastic insulated pre-branching cable" and expanding the product's application scope and market share. DETAILED DESCRIPTION

[0019] The present invention is described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by professionals and technicians in this field based on the content of the present invention above still belong to the scope of protection of the present invention.

[0020] Example 1 A low-smoke halogen-free flame-retardant cable material comprises the following components in parts by weight: 30 parts of polyethylene resin; 7 parts of silane-modified polyether resin 200D; 10 parts of a compatibilizer (composed of 5 parts of polyethylene glycol-grafted polyethyleneimine and 5 parts of maleic anhydride-grafted polyethylene); 1 part of a carbon black masterbatch; 30 parts of magnesium hydroxide; 5 parts of highly flame-retardant red phosphorus; 15 parts of antimony trioxide; 1 part of silicone; and 1 part of an antioxidant.

[0021] The polyethylene resin includes low-density polyethylene resin, linear low-density polyethylene resin, and metallocene linear low-density polyethylene resin, and the weight ratio is 1:1:1.

[0022] The silane-modified polyether resin 200D was purchased from Jiangsu Ruiyang Antai.

[0023] The antioxidants are antioxidant 1790 and antioxidant 168, and the weight ratio is 3:1.

[0024] This example also provides a method for preparing the cable material as described above, comprising the following steps: Step 1: polyethylene resin, silane-modified polyether resin, flame retardant, carbon black masterbatch, and antioxidant are mixed evenly, and a compatibilizer and silicone are added, and the mixture is continuously mixed to obtain a mixture; Step 2: feeding the mixture into a screw extruder for extrusion and granulation to obtain the cable material; the aspect ratio of the twin-screw extruder is 44:1; the temperatures of each section of the twin-screw extruder body are: 80°C-100°C, 125°C-130°C, 130°C-135°C, 135°C-140°C, 140°C-145°C, 145°C-150°C, 150°C-155°C; and the head temperature is 145°C-150°C.

[0025] Example 2 A low-smoke halogen-free flame-retardant cable material comprises the following components in parts by weight: 40 parts of polyethylene resin; 5 parts of silane-modified polyether resin 200D; 5 parts of compatibilizer (3 parts of polyethylene glycol grafted polyethyleneimine and 2 parts of maleic anhydride grafted polyethylene); 1 part of carbon black masterbatch; 30 parts of magnesium hydroxide; 2 parts of highly flame-retardant red phosphorus; 15 parts of antimony trioxide; 1 part of silicone; and 1 part of antioxidant. The rest is consistent with Example 1.

[0026] Example 3 A low-smoke halogen-free flame-retardant cable material comprises the following components in parts by weight: 40 parts of polyethylene resin; 10 parts of silane-modified polyether resin 200D; 7 parts of compatibilizer (4 parts of polyethylene glycol grafted polyethyleneimine and 3 parts of maleic anhydride grafted polyethylene); 1 part of carbon black masterbatch; 25 parts of magnesium hydroxide; 2 parts of highly flame-retardant red phosphorus; 13 parts of antimony trioxide; 1 part of silicone; and 1 part of antioxidant. The rest is consistent with Example 1.

[0027] Example 4 A low-smoke, halogen-free, flame-retardant cable material, wherein the silane-modified polyether resin adopts SAX260 (purchased from Japan Zhongyuan Chemical Industry), and the rest is consistent with Example 1.

[0028] Example 5 A low-smoke halogen-free flame-retardant cable material, wherein the silane-modified polyether resin adopts SAX260 and 200D in a weight ratio of 1:1, and the rest is consistent with Example 1.

[0029] Example 6 A low-smoke, halogen-free, flame-retardant cable material, wherein the compatibilizer is polyethylene glycol grafted polyethyleneimine, and the rest is consistent with Example 1.

[0030] Comparative Example 1 A low-smoke, halogen-free, flame-retardant cable material, wherein the compatibilizer is maleic anhydride grafted polyethylene, and the rest is consistent with Example 1.

[0031] Comparative Example 2 A low-smoke halogen-free flame-retardant cable material comprises the following components in parts by weight: 37 parts of polyethylene resin; 10 parts of compatibilizer (composed of 5 parts of polyethylene glycol grafted polyethyleneimine and 5 parts of maleic anhydride grafted polyethylene); 1 part of carbon black masterbatch; 30 parts of magnesium hydroxide; 5 parts of highly flame-retardant red phosphorus; 15 parts of antimony trioxide; 1 part of silicone; and 1 part of antioxidant. The rest is consistent with Example 1.

[0032] Comparative Example 3 A low-smoke, halogen-free, flame-retardant cable material, wherein the polyethylene resin is only a low-density polyethylene resin, and the rest is consistent with Example 1.

[0033] Performance Evaluation The cable materials provided in the embodiments and comparative examples should be prepared by molding or other suitable methods. The tubular sample can be cut and weighed, and preheated in a hydraulic press at 170℃-180℃ without pressure for 60s. Then it is pressurized for 4 minutes, and the pressure of the hydraulic press is greater than 15MPa. Cool to room temperature under pressure. The test piece should be flat and smooth, with uniform thickness and no bubbles. Then immerse the test piece in a water bath at a temperature of 90℃~95℃ for 0.5~4 hours. The test piece should still remain flat after warm water cross-linking. The performance characterization test results are shown in Table 1.

[0034] Table 1 Test items Melt flow rate (MFR) 170℃ 5kg Smoke density (with flame) Pre-branch cable connector combustion transmittance unit g / 10min / % Test Method ISO 1133 GB8323 / T IEC61034-2-2013 Example 1 7.2 76 86 Example 2 6.3 72 76 Example 3 6.6 75 81 Example 4 7.1 74 84 Example 5 7.5 73 88 Example 6 6.1 77 78 Comparative Example 1 2.6 72 63 Comparative Example 2 4.4 73 54 Comparative Example 3 5.6 75 71

[0035] Compared with Comparative Examples 1-3, Examples 1-6 solve the problems of poor fluidity and difficulty in injection molding of traditional halogen-free flame-retardant polyolefin materials by reasonably matching the types and proportions of raw materials, significantly improve the light transmittance, and take into account other necessary electrical properties (this application uses smoke density as a representative performance), achieving a breakthrough in the injection molding process and improving the safety and reliability of the pre-branching cable.

[0036] The foregoing examples are merely illustrative and are used to explain some features of the method of the present invention. The appended claims are intended to claim the widest possible range that can be conceived, and the embodiments presented herein are only illustrations of selected implementations according to the combination of all possible embodiments. Therefore, it is the applicant's intention that the appended claims are not limited by the selection of examples that illustrate the features of the present invention. Some numerical ranges used in the claims also include sub-ranges within them, and changes in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A low-smoke halogen-free flame-retardant cable material, characterized in that: The raw materials for preparing the cable material include, by weight: 30-40 parts of polyethylene resin; Silane modified polyether resin 5-10 parts; Compatibilizer 5-10 parts; Flame retardant 40-50 parts; 1 part antioxidant; 1 part of carbon black masterbatch; 1 part silicone.

2. The low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The polyethylene resin is selected from one or more of low-density polyethylene resin, linear low-density polyethylene resin, and metallocene linear low-density polyethylene resin.

3. The low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The silane-modified polyether resin is selected from one or more of Jiangsu Ruiyang Antai 200D and Japan Zhongyuan Chemical SAX260.

4. The low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The compatibilizer is selected from one or more of polyethylene glycol grafted polyethylene imine and maleic anhydride grafted polyethylene.

5. The low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The antioxidant is selected from one or more of phenolic antioxidants, phosphite antioxidants, and thioester antioxidants.

6. The low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The flame retardant is selected from one or more of magnesium hydroxide, highly flame-retardant red phosphorus and antimony trioxide.

7. A method for preparing a low-smoke halogen-free flame-retardant cable material according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: polyethylene resin, silane-modified polyether resin, flame retardant, carbon black masterbatch, and antioxidant are mixed evenly, and a compatibilizer and silicone are added, and the mixture is continuously mixed to obtain a mixture; Step 2: sending the mixture into a screw extruder for extrusion and granulation to obtain the cable material.

8. Use of the low-smoke halogen-free flame-retardant cable material according to any one of claims 1 to 6 for preparing a branch connector of a branch cable.