Low-friction smooth halogen-free low-smoke wire and cable material and preparation method thereof

Abstract

The invention discloses a low-friction smooth halogen-free low-smoke wire and cable material and a preparation method thereof. The cable material comprises the following raw material components in parts by weight: 35-60 parts of matrix resin, 4-15 parts of graft modified resin, 5-10 parts of an organic phosphorus-nitrogen flame retardant, 4-10 parts of flame-retardant master batch, 45-75 parts of an inorganic flame retardant, 3-7 parts of a lubricating additive and 2-5 parts of an antioxidant. The low-friction, smooth, halogen-free and low-smoke wire and cable material is developed and researched aiming at existing market requirements and technical vacancies, through the synergistic effect of the components, the low-friction property is achieved (the processing energy consumption is remarkably reduced), the tensile strength is 12.4-13.0 MPa, the elongation at break is 224-255%, and the low-friction, smooth, halogen-free and low-smoke wire and cable material passes the UL-94V0 level and GB / T 18380 vertical combustion test.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, specifically to a low-friction, smooth, halogen-free, low-smoke wire and cable material and its preparation method. Background Technology

[0002] Against the backdrop of global energy structure transformation and the popularization of green and environmentally friendly concepts, the safety and environmental friendliness of electrical equipment and related products have become core indicators for industry development. As a key component protecting the internal conductors from the influence of the external environment, the weather resistance, flame retardancy, and low smoke characteristics of cable sheath materials directly affect the service life and operational reliability of cables.

[0003] Cables used outdoors or in harsh environments often face multiple challenges, including ultraviolet radiation, extreme temperature changes, moisture erosion, and chemical corrosion. Traditional cable sheath materials are prone to aging, embrittlement, and cracking under these conditions, leading to decreased insulation performance and even causing safety accidents such as short circuits and fires.

[0004] Currently, my country's requirements for the weather resistance of halogen-free wire and cable materials are relatively low compared to international standards. Furthermore, traditional halogen-free materials, in pursuit of flame retardant properties, typically require large amounts of inorganic flame retardants, leading to a significant decrease in mechanical properties and weather resistance, making it difficult to meet long-term usage requirements under extreme conditions. Simultaneously, high friction during processing results in high energy consumption and easy material decomposition. Therefore, developing a low-friction, smooth, halogen-free, low-smoke wire and cable material that maintains good physicochemical stability even with high inorganic flame retardant filling, while possessing both excellent flame retardancy and processing performance, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the problems of poor weather resistance, insufficient mechanical properties, high energy consumption due to high friction during processing, and easy decomposition of materials in existing cable technologies, this invention provides a low-friction, smooth, halogen-free, low-smoke wire and cable material and its preparation method. The aim is to achieve high weather resistance, excellent mechanical properties, low friction and easy processing characteristics, while meeting strict flame retardant standards.

[0006] The present invention adopts the following technical solution:

[0007] A low-friction, smooth, halogen-free, low-smoke wire and cable compound is prepared from the following raw materials in parts by weight:

[0008]

[0009] Wherein, the matrix resin is a blend of at least two of PE, EVA, POE and EMA resins, and satisfies the following conditions:

[0010] (a) PE resin melt index ≥ 0.15 g / 10 min, density ≤ 0.93 g / cm³3 ;

[0011] (b) The VA content in the EVA resin is 22-28wt%, the melt index is 6-25g / 10min, and the mass ratio of low melt index EVA to high melt index EVA is (4-7):(0.5-1);

[0012] (c) POE resin melt index ≥ 0.35 g / 10 min;

[0013] (d) The MA content in the EMA resin is 24-29 wt%.

[0014] Preferably, the matrix resin is composed of PE, POE and EMA in a mass ratio of (2-5):(7-11):(6-9).

[0015] Preferably, the grafted modified resin is selected from at least one of maleic anhydride grafted matrix resin, maleic anhydride grafted polyethylene, and maleic anhydride grafted polyolefin elastomer, and the grafting rate is ≥0.6%.

[0016] Preferably, the inorganic flame retardant is a mixture of modified aluminum hydroxide and modified magnesium hydroxide, with a mass ratio of (7-9):(1-2); wherein the particle sizes of aluminum hydroxide and magnesium hydroxide satisfy: D50=1.8-3.0μm, D90=2.4-5.0μm, and the modification treatment uses at least one of zirconium coupling agent, silane coupling agent or organic acid.

[0017] Preferably, the flame retardant masterbatch contains ≥85wt% of flame retardant active ingredients, which are at least one of ultrafine zinc borate, ammonium polyphosphate, and aluminum hypophosphite, and have a particle size of 4-10μm; the carrier resin of the flame retardant masterbatch is an EVA / POE composite with added silicone masterbatch.

[0018] Preferably, the organophosphorus-nitrogen flame retardant is selected from at least one of dimethyl methylphosphonate, diphenyl phosphate, and melamine derivatives.

[0019] Preferably, the lubricant is selected from at least one of silane coupling agent, silicone masterbatch, and polyethylene wax; the antioxidant is selected from at least one of antioxidant 1010, tris(2,4-di-tert-butylphenyl) phosphite, dilauryl thiodipropionate, and dioctadecyl thiodipropionate.

[0020] The low melt index EVA has a melt index of 6-15 g / 10 min, and the high melt index EVA has a melt index of 16-25 g / 10 min.

[0021] A method for preparing a low-friction, smooth, halogen-free, low-smoke wire and cable material includes the following steps:

[0022] S1. Preheat the internal mixer to 130-140℃, and add the raw materials in the following order: resin → masterbatch → lubricant → powder.

[0023] S2. When the material temperature reaches 110℃, stop mixing, clean the powder adhering to the wall of the mixing chamber, and continue mixing until the material temperature reaches 145-155℃.

[0024] S3. The mortar is plasticized, extruded, pelletized and cooled by a twin-screw extruder to obtain the required cable material.

[0025] Preferably, the twin-screw plasticizing process is divided into 8 temperature zones:

[0026] Zone I: 90-100℃, Zone II: 90-105℃, Zone III: 100-110℃, Zone IV: 110-125℃, Zone V: 110-130℃, Zone VI: 120-140℃, Zone VII: 110-120℃, Zone VIII: 100-115℃.

[0027] Compared with the prior art, the technical solution of this invention has the following advantages:

[0028] A. High weather resistance: Through the synergistic effect of antioxidants and modified flame retardants, the material can maintain long-term stability in extreme environments by passing the hot water immersion aging test (GB / T 1040.3) and water cycle aging test (IEC60800), thus solving the problem of easy aging of traditional materials.

[0029] B. Excellent mechanical properties: Tensile strength reaches 12.4-13.0MPa, elongation at break is 224-255%. Through compatibility optimization of the matrix resin and grafted modified resin, it still maintains good mechanical properties even with high inorganic flame retardant filling.

[0030] C. Low friction and easy production: The lubricant significantly reduces friction during processing, and the main machine current drops from 35A to 27A, reducing energy consumption and the risk of material decomposition. The actual extrusion temperature is closer to the set temperature, and the processing stability is improved.

[0031] D. Excellent flame retardancy: Passes the UL-94V0 vertical burning test and the GB / T 18380 single-insulated wire and cable flame vertical spread test, meeting stringent flame retardant standards. Detailed Implementation

[0032] This invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. All other embodiments derived by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0033] Example 1

[0034] This embodiment provides a low-friction, smooth, halogen-free, low-smoke wire and cable material, which is made from the following raw material ratios by weight:

[0035]

[0036]

[0037] Of the above-mentioned components by weight, the matrix resin is composed of PE, POE, and EMA in a mass ratio of 2:11:6, with the PE resin having a melt flow index ≥0.15 g / 10 min and a density ≤0.93 g / cm³. 3 The POE resin has a melt index ≥0.35 g / 10 min; the MA content in the EMA resin is 24-29 wt%. The grafted modified resin is maleic anhydride-grafted polyolefin elastomer with a grafting rate ≥0.6%. The inorganic flame retardant is a mixture of modified aluminum hydroxide and modified magnesium hydroxide in a mass ratio of 7:2, and the modification treatment uses a silane coupling agent. The flame retardant masterbatch contains ≥85 wt% flame retardant active ingredient, which is a mixture of ultrafine zinc borate and ammonium polyphosphate. The carrier resin of the flame retardant masterbatch is an EVA / POE composite with added silicone masterbatch. The organophosphorus-nitrogen flame retardant is dimethyl methylphosphonate; the lubricant is a mixture of silane coupling agent and polyethylene wax; the antioxidant is dilauryl thiodipropionate.

[0038] The preparation method is as follows:

[0039] S1. Preheat the internal mixer to 130-140℃, and add the raw materials in the following order: resin → masterbatch → lubricant → powder.

[0040] S2. When the material temperature reaches 110℃, stop mixing, clean the powder adhering to the wall of the mixing chamber, and continue mixing until the material temperature reaches 145-155℃.

[0041] S3. The mortar is plasticized, extruded, pelletized and cooled by a twin-screw extruder to obtain the required cable material.

[0042] The twin-screw plasticizing process is divided into eight temperature zones: Zone I: 90-100℃, Zone II: 90-105℃, Zone III: 100-110℃, Zone IV: 110-125℃, Zone V: 110-130℃, Zone VI: 120-140℃, Zone VII: 110-120℃, and Zone VIII: 100-115℃.

[0043] Example 2

[0044] This embodiment provides a low-friction, smooth, halogen-free, low-smoke wire and cable material, which is made from the following raw material ratios by weight:

[0045]

[0046]

[0047] Of the above-mentioned components by weight, the matrix resin is composed of PE, POE, and EMA in a mass ratio of 4:10:8, with the PE resin having a melt flow index ≥0.15 g / 10 min and a density ≤0.93 g / cm³. 3 The POE resin has a melt index ≥0.35 g / 10 min; the MA content in the EMA resin is 24-29 wt%. The grafted modified resin is maleic anhydride-grafted polyethylene with a grafting rate ≥0.6%. The inorganic flame retardant is a mixture of modified aluminum hydroxide and modified magnesium hydroxide in a mass ratio of 8:1; and the modification treatment uses a zirconium coupling agent. The flame retardant masterbatch contains ≥85 wt% of flame retardant active ingredient, which is ultrafine zinc borate. The carrier resin of the flame retardant masterbatch is an EVA / POE composite with added silicone masterbatch; the organophosphorus-nitrogen flame retardant is diphenyl phosphate. The lubricant is polyethylene wax; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite.

[0048] The preparation method is the same as in Example 1.

[0049] Example 3

[0050] This embodiment provides a low-friction, smooth, halogen-free, low-smoke wire and cable material, which is made from the following raw material ratios by weight:

[0051]

[0052] Of the above-mentioned components by weight, the matrix resin is composed of PE, POE, and EMA in a mass ratio of 5:7:9. The PE resin has a melt index ≥0.15 g / 10 min and a density ≤0.93 g / cm³. 3 The POE resin has a melt index ≥0.35 g / 10 min; the MA content in the EMA resin is 24-29 wt%. The grafted modified resin is a maleic anhydride-grafted matrix resin with a grafting rate ≥0.6%. The inorganic flame retardant is a mixture of modified aluminum hydroxide and modified magnesium hydroxide in a mass ratio of 9:2, and the modification treatment uses a silane coupling agent. The flame retardant masterbatch contains ≥85 wt% of the flame retardant active ingredient, which is aluminum hypophosphite. The carrier resin of the flame retardant masterbatch is an EVA / POE composite with added silicone masterbatch. The organophosphorus-nitrogen flame retardant is a mixture of dimethyl methylphosphonate and melamine derivative; the lubricant is silicone masterbatch; and the antioxidant is dioctadecanothiopropionate.

[0053] The preparation method is the same as in Example 1.

[0054] Comparative Example 1

[0055] This comparative example provides a cable material, which, by weight, is made from the following raw materials in the following proportions:

[0056]

[0057] Compared with Example 1, the grafted modified resin and lubricant are missing, but the other components and preparation methods are the same as in Example 1.

[0058] The cable materials prepared in Examples 1-3 and Comparative Example 1 were subjected to performance testing. The measured technical indicators are shown in the table below.

[0059] Table 1 Test data of cable material properties

[0060]

[0061]

[0062] Table 2 Extrusion Performance Data of Cable Material

[0063] project Example 1 Example 2 Example 3 Example 4 Extruder 70# 70# 70# 70# Main unit speed (RPM) 50 50 50 50 Host current (A) 32 29 27 35 Set temperature (°C) 150 150 150 150 Actual temperature (°C) 162 155 150 172

[0064] As shown in Table 1, the elongation at break of Examples 1-3 was 224-255%, significantly higher than the 190% of the comparative example. This is because the grafted modified resin added in this invention forms chemical bonds with the surface modified groups of the inorganic flame retardant through polar groups, improving the interfacial bonding force between the matrix resin and the inorganic flame retardant, reducing stress concentration, and overcoming the problem of insufficient toughness caused by the lack of this component in the comparative example. In terms of tensile strength, Examples 1-3 were 12.4-13.0 MPa, close to the 13.1 MPa of the comparative example. This indicates that under high inorganic flame retardant filling, this invention achieves a balance between strength and toughness through the synergy of the PE / POE / EMA blend matrix and the grafted modified resin, solving the defect of "increased stiffness inevitably leads to brittleness" in traditional high-filler materials. Regarding weather resistance, Examples 1-3 all passed the hot water immersion aging test (GB / T 1040.3) and the water cycle aging test (IEC60800), while the comparative example failed. This is attributed to the antioxidants (such as thiodipropionates) capturing free radicals and delaying oxidation, as well as the synergistic effect of the grafted modified resin reducing the channels for moisture and oxygen permeation. In terms of processing performance, the main machine current of Examples 1-3 was 27-32A, lower than the 35A of the comparative example, and the actual extrusion temperature was closer to the set value of 150℃. This is because the silicone masterbatch in the lubricant forms a low surface energy lubricating layer, and the polyethylene wax reduces intramolecular friction, thus reducing processing energy consumption and the risk of material decomposition. Regarding flame retardant performance, both the examples and the comparative example passed the UL-94V0 level and GB / T18380.12 tests. The organophosphorus nitrogen flame retardant of this invention, containing ≥85wt% ultrafine flame retardant components in the flame retardant masterbatch and inorganic flame retardant, forms a "gas phase-condensed phase" synergistic mechanism, ensuring flame retardant effect while improving overall performance.

[0065] The above embodiments demonstrate that the present invention achieves synergistic optimization of the material's weather resistance, mechanical properties, processing performance, and flame retardancy through specific component ratios and preparation processes, exhibiting significant technical advantages.

[0066] Any aspects not described in this invention are applicable to existing technologies.

[0067] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A low-friction, smooth, halogen-free, low-smoke wire and cable material, characterized in that, It is prepared from the following raw materials in parts by weight: Wherein, the matrix resin is a blend of at least two of PE, EVA, POE and EMA resins, and satisfies the following conditions: (a) PE resin melt index ≥ 0.15 g / 10 min, density ≤ 0.93 g / cm³ 3 ; (b) The VA content in the EVA resin is 22-28wt%, the melt index is 6-25g / 10min, and the mass ratio of low melt index EVA to high melt index EVA is (4-7):(0.5-1); (c) POE resin melt index ≥ 0.35 g / 10 min; (d) The MA content in the EMA resin is 24-29 wt%.

2. The cable material according to claim 1, characterized in that, The grafted modified resin is selected from at least one of maleic anhydride grafted matrix resin, maleic anhydride grafted polyethylene, and maleic anhydride grafted polyolefin elastomer, and the grafting rate is ≥0.6%.

3. The cable material according to claim 1, characterized in that, The inorganic flame retardant is a mixture of modified aluminum hydroxide and modified magnesium hydroxide, with a mass ratio of (7-9):(1-2); wherein the particle sizes of aluminum hydroxide and magnesium hydroxide satisfy: D50=1.8-3.0μm, D90=2.4-5.0μm, and the modification treatment uses at least one of zirconium coupling agent, silane coupling agent or organic acid.

4. The cable material according to claim 1, characterized in that, The flame retardant masterbatch contains ≥85wt% of flame retardant active ingredients, which are at least one of ultrafine zinc borate, ammonium polyphosphate, and aluminum hypophosphite, with a particle size of 4-10μm; the carrier resin of the flame retardant masterbatch is an EVA / POE composite with added silicone masterbatch.

5. The cable material according to claim 1, characterized in that, The organophosphorus-nitrogen flame retardant is selected from at least one of dimethyl methylphosphonate, diphenyl phosphate, and melamine derivatives.

6. The cable material according to claim 1, characterized in that, The lubricant is selected from at least one of silane coupling agents, silicone masterbatches, and polyethylene wax; the antioxidant is selected from at least one of antioxidant 1010, tris(2,4-di-tert-butylphenyl) phosphite, dilauryl thiodipropionate, and dioctadecyl thiodipropionate.

7. The cable material according to claim 1, characterized in that, The low melt index EVA has a melt index of 6-15 g / 10 min, and the high melt index EVA has a melt index of 16-25 g / 10 min.

8. A method for preparing a low-friction, smooth, halogen-free, low-smoke wire and cable material according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Preheat the internal mixer to 130-140℃, and add the raw materials in the following order: resin → masterbatch → lubricant → powder. S2. When the material temperature reaches 110℃, stop mixing, clean the powder adhering to the wall of the mixing chamber, and continue mixing until the material temperature reaches 145-155℃. S3. The mortar is plasticized, extruded, pelletized and cooled by a twin-screw extruder to obtain the required cable material.

9. The preparation method according to claim 8, characterized in that, The twin-screw plasticizing process is divided into 8 temperature zones: Zone I: 90-100℃, Zone II: 90-105℃, Zone III: 100-110℃, Zone IV: 110-125℃, Zone V: 110-130℃, Zone VI: 120-140℃, Zone VII: 110-120℃, Zone VIII: 100-115℃.

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