Environment-friendly polypropylene wire for home decoration

Abstract

The invention discloses an environment-friendly polypropylene electric wire for home decoration. According to the insulation material of the polypropylene wire, the polypropylene / elastomer composite material is modified by adopting two means of crystal form regulation and control and chemical grafting, and the composite material not only keeps good mechanical properties, but also has excellent high-temperature mechanical and electrical properties. Meanwhile, the novel nano flame retardant is adopted, and the product can still have good flame retardant property under the condition of high temperature resistance due to excellent char forming effect and gas barrier effect. And cable use, processing performance, installation and laying requirements are satisfied.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to an environmentally friendly polypropylene electric wire for home decoration. Background Art

[0002] Traditional home decoration wiring insulation materials are basically made of halogen-containing PVC materials. However, when halogen-containing cables burn, they will produce toxic halogenated hydrogen smoke, which will make the victims lose their way and affect their breathing, making it difficult for them to escape from the fire scene, causing serious casualties. At the same time, the halogenated hydrogen acid produced by the combustion will seriously corrode the on-site equipment, causing permanent or intermittent equipment failures, hindering its subsequent reliable operation, and thus causing great economic losses. Various painful lessons from fire hazards have made people increasingly aware of the importance of using environmentally friendly halogen-free materials. In addition, it is also difficult for PVC materials to achieve a temperature resistance of 105°C. Most of the existing cable materials with a temperature resistance of more than 105°C use irradiated cross-linked polyolefin cable materials. Irradiated cross-linked cable materials have the following main disadvantages: 1. Unsatisfactory flame retardancy; 2. Large amounts of flame retardants are added, and subsequent product quality control is difficult to control, and the material has a heavy specific gravity, generally 1.45g / cm 3 The surface is relatively rough, the processability is unstable, the product performance is not stable, and the wire must be irradiated and cross-linked to meet the high temperature resistance requirements, which increases the subsequent processing time and economic costs. In addition, since irradiation belongs to the radiation hazard industry, the state controls irradiation equipment more strictly; 3. The cross-linked polyolefin wire is a thermosetting material and cannot be recycled. Therefore, it is difficult to call the irradiated cross-linked wire an environmentally friendly wire in the strict sense.

[0003] At present, the main modification methods for polypropylene include blending modification, copolymerization modification, addition of nucleating agents and nano addition. The electrical properties of polypropylene are improved to a certain extent by modifying polypropylene through nano doping and chemical grafting, but its mechanical properties have not been significantly improved. Adding elastomers can effectively improve the mechanical properties of polypropylene, but when the amount added is small, the improvement effect on the mechanical properties of polypropylene is not obvious, and there is still a certain gap with cross-linked polyethylene; when the amount added is too much, due to the low melting point and high content of the elastomer, the crystallinity of the blend decreases, the binding ability of polypropylene crystals on the chain segments at high temperatures is reduced, and the chain segment relaxation is aggravated, resulting in a weakened resistance to thermal deformation of the material and a significant deterioration of the electrical properties. Therefore, the simultaneous improvement of the high-temperature mechanical and electrical properties of the polypropylene / elastomer composite system is a key issue for the use of polypropylene in cable insulation materials.

[0005] Therefore, it is of great economic and social significance to develop halogen-free flame-retardant and radiation-free wire and cable products with good processability and various mechanical properties and a temperature resistance of up to 105°C. Summary of the invention

[0006] The object of the present invention is to overcome at least one disadvantage of the prior art and provide an environmentally friendly polypropylene wire for home decoration.

[0007] The technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides a composite polypropylene insulating material, wherein a method for preparing the composite polypropylene insulating material comprises the following steps:

[0009] 1) blending a polypropylene raw material with a rare earth nucleating agent to form granules to obtain β-crystalline polypropylene;

[0010] 2) The beta-crystalline polypropylene, elastomer, grafting agent and flame retardant obtained in step 1) are blended and granulated in a mass ratio of 200:100:1:(25-35) to obtain a composite polypropylene insulation material.

[0011] In some examples, the mass ratio of the polypropylene raw material to the rare earth nucleating agent is (95-96):5.

[0012] In some examples, the elastomer is selected from any one of POE, PBE, EPR, EPDM, SEBS and SBS.

[0013] In some examples, the grafting agent is selected from any one of acrylic acid, acrylic acid ester, maleic acid, maleic anhydride or methylene succinic acid.

[0014] In some examples, the rare earth nucleating agent is WBG-II.

[0015] In some examples, the flame retardant is selected from magnesium hydroxide or aluminum hydroxide.

[0016] In some examples, the granulation process of step 1) and step 2) is performed by using a twin-screw extruder.

[0017] In some examples, the compression ratio of the screw of the twin-screw extruder is 1.2-1.4.

[0018] In some examples, the temperature of the twin-screw extruder from the feed port to the die port is sequentially set to 180-190°C in the feeding section, 200-210°C in the compression section, 205-210°C in the metering section, and 180-190°C in the die.

[0019] In a second aspect, the present invention provides an environmentally friendly polypropylene electric wire for home decoration, wherein the insulating layer of the electric wire is the composite polypropylene insulating material described in the first aspect.

[0020] The beneficial effects of the present invention are:

[0021] The present invention adopts two methods, crystal form regulation and chemical grafting, to modify the polypropylene / elastomer composite material. The composite material not only maintains good mechanical properties, but also has excellent high-temperature mechanical and electrical properties. At the same time, a new type of nano flame retardant is used, which has excellent carbonization effect and gas barrier effect, so that the product can still have good flame retardant properties under high temperature resistance. It meets the requirements of cable use, processing performance and installation and laying.

[0022] The composite polypropylene material is used as the insulation layer to extrude the finished wire. A screw with a compression ratio of 1.2-1.4 is used, which is close to the compression ratio of conventional low-smoke halogen-free products, but the head of the screw is treated accordingly, and the conventional flat head is changed to a special pointed head, which reduces the storage of the extruder screw head and the neck, improves the plasticization degree of the material, and reduces the scorching caused by long storage time. Because polypropylene material is a non-polar polymer, there is internal stress after extrusion. In order to eliminate the internal stress of the material, the product should be treated with high temperature (refer to 9.1.3 in GB / T2951.11, placed at 70±2℃ for 24h) and then measure its elongation at break and tensile strength. After treatment, the elongation at break is more than 120% and the strength is more than 10.0Mpa. After aging at high temperature of 135℃ for 7 days, its elongation at break can still be maintained at more than 60%. Without cross-linking, the high temperature pressure test can reach less than 40%. The product does not contain heavy metals harmful to the human body (meets ROHS requirements) and has excellent flame retardant properties and a long service life. After the service life of the wire product ends, the waste can be recycled and reused.

[0023] Through the application of this material, a radiation-free, 105°C temperature-resistant, low-smoke, halogen-free polypropylene wire has been produced. Compared with traditional PVC wires, its temperature resistance is higher than 70°C, and it will not produce hydrogen chloride and other toxic gases after combustion. Compared with 105° irradiation cross-linked low-smoke, halogen-free, flame-retardant polyolefin insulated wires, it does not require irradiation processing, reducing radiation damage. At the same time, the product can be recycled and will not cause harm to the environment when discarded. There will be no spread of carcinogens such as dioxins. It is a truly environmentally friendly wire product. DETAILED DESCRIPTION

[0024] The following disclosure provides many different embodiments or examples for implementing different solutions of the present invention.

[0025] Example 1

[0026] The method for preparing the composite polypropylene insulating material of the present embodiment comprises the following steps:

[0027] 1) Putting the polypropylene raw material and the rare earth nucleating agent WBG-Ⅱ into a twin-screw extruder at a mass ratio of 95:5, blending and granulating, and obtaining β-crystalline polypropylene;

[0028] 2) The β-crystalline polypropylene, POE, maleic anhydride and aluminum hydroxide obtained in step 1) are blended and granulated in a mass ratio of 200:100:1:30 to obtain a composite polypropylene insulating material.

[0029] The parameters of the twin-screw extruder are set as follows: the compression ratio of the screw of the twin-screw extruder is 1.2 to 1.4;

[0030] The temperature of the twin-screw extruder from the feed port to the die port was set to 185°C in the feeding section, 205°C in the compression section, 210°C in the metering section, and 185°C in the die head.

[0031] Comparative Example 1

[0032] The difference between this comparative example and Example 1 is that in step 2), the mass ratio of β-crystalline polypropylene, POE, maleic anhydride and aluminum hydroxide is 200:100:1:20.

[0033] Comparative Example 2

[0034] The difference between this comparative example and Example 1 is that in step 2), the mass ratio of β-crystalline polypropylene, POE, maleic anhydride and aluminum hydroxide is 200:100:1:10.

[0035] Performance Testing

[0036] The elongation at break is determined in accordance with GB / T 1040-1992 Test method for tensile properties of plastics. During the test, the sample is stretched at a speed of 25 mm / min.

[0037] Oxygen index test: Test in accordance with ASTM D2863 or BS EN ISO 4589-3, requiring the oxygen index at room temperature to be ≥30.

[0038] The experimental test results are shown in Table 1 below.

[0039] Table 1

[0040] Ratio Example 1 Comparative Example 1 Comparative Example 2 Elongation at break 200％ 280％ 350％ Oxygen Index 32 28 24

[0041] It can be seen from the results in Table 1 that the composite material not only maintains good mechanical properties, but also has excellent high temperature mechanics.

[0042] The above is a further detailed description of the present invention, which should not be regarded as a limitation on the specific implementation of the present invention. For ordinary technicians in the technical field to which the present invention belongs, simple deduction or replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A composite polypropylene insulating material, characterized in that: The preparation method of the composite polypropylene insulating material comprises the following steps: 1) blending a polypropylene raw material with a rare earth nucleating agent to form granules to obtain β-crystalline polypropylene; 2) The beta-crystalline polypropylene, elastomer, grafting agent and flame retardant obtained in step 1) are blended and granulated in a mass ratio of 200:100:1:(25-35) to obtain a composite polypropylene insulation material.

2. The composite polypropylene insulating material according to claim 1, characterized in that: The mass dosage ratio of the polypropylene raw material to the rare earth nucleating agent is (95-96):

5.

3. The composite polypropylene insulating material according to claim 1, characterized in that: The elastomer is selected from any one of POE, PBE, EPR, EPDM, SEBS and SBS.

4. The composite polypropylene insulating material according to claim 1, characterized in that: The grafting agent is selected from any one of acrylic acid, acrylic ester, maleic acid, maleic anhydride or methylene succinic acid.

5. The composite polypropylene insulating material according to claim 1 or 2, characterized in that: The rare earth nucleating agent is WBG-Ⅱ.

6. The composite polypropylene insulating material according to claim 1, characterized in that: The flame retardant is selected from magnesium hydroxide or aluminum hydroxide.

7. The composite polypropylene insulating material according to claim 1, characterized in that: The granulation process of step 1) and step 2) is carried out by using a twin-screw extruder.

8. The composite polypropylene insulating material according to claim 7, characterized in that: The compression ratio of the screw of the twin-screw extruder is 1.2 to 1.

4.

9. The composite polypropylene insulating material according to claim 7, characterized in that: The temperature of the twin-screw extruder from the feed port to the die port is sequentially set to 180-190°C in the feeding section, 200-210°C in the compression section, 205-210°C in the metering section, and 180-190°C in the die head.

10. An environmentally friendly polypropylene wire for home decoration, characterized in that: The insulating layer of the electric wire is the composite polypropylene insulating material according to any one of claims 1 to 9.