Flame-retardant cable sheath material and preparation method thereof

Abstract

The invention relates to a flame-retardant cable sheath material and a preparation method thereof, and relates to the technical field of cable materials, the flame-retardant cable sheath material comprises a polyolefin composition, a flame retardant and an auxiliary agent; the flame retardant is prepared from modified magnesium hydroxide and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the weight ratio of the modified magnesium hydroxide to the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is (3.5 to 5.8) to 1. Compared with the prior art, the preparation method has the advantages that the modified magnesium hydroxide is obtained by modifying the compound which is provided with the spirodiindane structure and has a symmetrical molecular skeleton and is shown in the formula I, so that on one hand, the matching property of the spirodiindane structure and a non-polar polyolefin matrix is utilized, and the compatibility between the spirodiindane structure and the non-polar polyolefin matrix is improved; the compatibility of magnesium hydroxide and a matrix is improved; the mechanical property of the material is enhanced; and on the other hand, through compounding with a proper amount of DOPO, a compact carbon layer rich in aromatic rings can be formed, and the flame-retardant effect is further improved, so that the flame-retardant cable sheath material with high flame retardance and high mechanical properties is obtained.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, and in particular to a flame-retardant cable sheath material and its preparation method. Background Technology

[0002] In the field of cable material technology, cable sheath materials play a crucial role in protecting the internal conductors and insulation layers of cables. Their performance directly affects the cable's service life, safety, and stable operation in various complex environments. Among these, flame retardancy is one of the most important performance indicators for cable sheath materials. Good flame retardancy can effectively prevent the spread of flames in the event of a fire, reducing fire damage and protecting lives and property. Simultaneously, with the continuous expansion and increasing complexity of cable applications, higher requirements are being placed on the mechanical properties of cable sheath materials to ensure that cables can withstand various external forces without damage during laying and operation.

[0003] Currently, most common flame-retardant cable sheathing materials on the market use polyolefin as the matrix material and add flame retardants to improve flame-retardant performance. Polyolefin materials have excellent electrical insulation, chemical corrosion resistance, and processing performance, and are relatively inexpensive, thus they are widely used in the cable sheathing field. However, traditional flame retardants have certain problems with compatibility with polyolefin matrices. For example, magnesium hydroxide, as a commonly used inorganic flame retardant, has advantages such as good flame retardant effect, non-toxicity, and smoke suppression. However, due to its strong surface polarity, its compatibility with non-polar polyolefin matrices is poor, resulting in uneven dispersion in the material and easy agglomeration. This not only reduces the mechanical properties of the material, such as tensile strength and elongation at break, but also affects the full realization of the flame-retardant effect, making it difficult to meet the dual requirements of high flame retardancy and high mechanical properties.

[0004] Therefore, there is an urgent need to develop a flame-retardant cable sheath material that combines high flame retardancy and high mechanical properties to meet the ever-evolving needs of the cable industry. Summary of the Invention

[0005] To address the above problems, this invention provides a flame-retardant cable sheath material and its preparation method.

[0006] In a first aspect, the present invention provides a flame-retardant cable sheath material, the flame-retardant cable sheath material comprising a polyolefin composition, a flame retardant, and additives; The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of (3.5-5.8):1. The modified magnesium hydroxide is obtained by modifying magnesium hydroxide as a raw material with the compound shown in Formula I. Equation I: R1, R2, R3, and R4 are each independently hydroxyl and amino groups.

[0007] Furthermore, the compound shown in Formula I includes at least one of compound 1 and compound 2; The chemical structure of compound 1 is shown below: ; The chemical structure of compound 2 is shown below: .

[0008] Furthermore, the flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 4.7:1.

[0009] Furthermore, the preparation of the modified magnesium hydroxide includes the following process: The magnesium hydroxide and silane coupling agent were added to an alcohol-water mixture of ethanol and water and stirred for the first time. Then, the compound shown in Formula I was added and stirred for the second time. The mixture was filtered and the resulting solid was washed and dried to obtain the modified magnesium hydroxide. The weight ratio of the magnesium hydroxide, the compound shown in Formula I, the silane coupling agent, and the alcohol-water mixed solution is 100:(7-12):(3-6):(400-500); the working conditions of the first stirring include: temperature of 40-50℃ and time of 30-60min; the working conditions of the second stirring include: temperature of 40-50℃ and time of 90-120min.

[0010] Furthermore, based on 100 parts by weight of the polyolefin composition, the amount of flame retardant added is 10-15 parts by weight.

[0011] Furthermore, based on 100 parts by weight of the polyolefin composition, the amount of the additive added is 1-5 parts by weight.

[0012] Furthermore, the additives include at least one of a lubricant and an antioxidant; the lubricant includes polyethylene wax, and the antioxidant includes antioxidant 1010.

[0013] Furthermore, the polyolefin composition is composed of materials with a density of 0.941-0.960 g / cm³. 3 High-density polyethylene with a density of 0.910-0.925 g / cm³ 3 It is composed of low-density polyethylene, wherein the weight ratio of high-density polyethylene to low-density polyethylene is (70-75):(25-30).

[0014] Secondly, based on the same inventive concept, the present invention provides a method for preparing the flame-retardant cable sheath material described in the first aspect, comprising the following steps: The raw materials are then thoroughly mixed to obtain a mixture. The mixture is melt-extruded and granulated to obtain the flame-retardant cable sheath material.

[0015] Furthermore, the mixing temperature is 155-160℃, and the melt extrusion temperature is 165-170℃.

[0016] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art: This invention provides a flame-retardant cable sheath material and its preparation method. Compared with the prior art, this invention mainly introduces modified magnesium hydroxide obtained by modifying a compound of Formula I with a spirocyclic diindene structure and a symmetrical molecular skeleton. On the one hand, the compatibility between the spirocyclic diindene structure and the non-polar polyolefin matrix is ​​utilized to improve the compatibility between magnesium hydroxide and the matrix and enhance the mechanical properties of the material. On the other hand, by compounding with an appropriate amount of DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), it is beneficial to form a dense carbon layer rich in aromatic rings, further improving the flame-retardant effect, thereby obtaining a flame-retardant cable sheath material with both high flame retardancy and high mechanical properties. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods; for example, Compound 1, Compound 2, and aluminum hydroxide can all be commercially available products. Furthermore, unless otherwise specified or detailed, the steps and parameters involved in this invention can be carried out according to the existing flame-retardant cable sheath material preparation process or directly using existing equipment, and will not be elaborated further in this application.

[0019] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0020] Example 1 This example provides a flame-retardant cable sheath material, including a polyolefin composition, a flame retardant, and additives; The polyolefin composition is composed of high-density polyethylene (product model HSGC7260) and low-density polyethylene (product model DJ210), with a weight ratio of high-density polyethylene to low-density polyethylene of 73:27. The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 4.7:1. The preparation of the modified magnesium hydroxide includes the following process: magnesium hydroxide (particle size of 2µm) and a silane coupling agent (specifically KH-550, γ-aminopropyltriethoxysilane) are added to an alcohol-water mixture (ethanol and water in a volume ratio of 4:1, with the pH adjusted to 4.5 by adding an appropriate amount of glacial acetic acid) for the first stirring; then the compound shown in Formula I (specifically compound 1) is added for the second stirring; the mixture is filtered, and the resulting solid is washed and dried to obtain the modified magnesium hydroxide; wherein the weight ratio of the magnesium hydroxide, the compound shown in Formula I, the silane coupling agent, and the alcohol-water mixture is 100:9:5:450; the operating conditions for the first stirring include a temperature of 45℃ and a time of 45 min; the operating conditions for the second stirring include a temperature of 45℃ and a time of 100 min. The chemical structure of compound 1 is shown below: ; Based on 100 parts by weight of the polyolefin composition, the flame retardant is added in the amount of 12 parts by weight and the additive is added in the amount of 3 parts by weight, the additive being composed of a lubricant (specifically polyethylene wax, 1.5 parts) and an antioxidant (specifically antioxidant 1010, 1.5 parts).

[0021] The preparation method of the above-mentioned flame-retardant cable sheath material includes the following steps: The raw materials are intensively mixed at 158°C for 12 minutes to obtain a mixture; the mixture is then melt-extruded and granulated at 167°C to obtain the flame-retardant cable sheath material.

[0022] Example 2 This example provides a flame-retardant cable sheath material, including a polyolefin composition, a flame retardant, and additives; The polyolefin composition is composed of high-density polyethylene (product model HSGC7260) and low-density polyethylene (product model DJ210), with the weight ratio of high-density polyethylene to low-density polyethylene being 70:30. The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 3.5:1. The preparation of the modified magnesium hydroxide includes the following process: magnesium hydroxide (particle size of 2µm) and a silane coupling agent (specifically KH-550, γ-aminopropyltriethoxysilane) are added to an alcohol-water mixture (ethanol and water in a volume ratio of 4:1, with the pH adjusted to 4.5 by adding an appropriate amount of glacial acetic acid) for the first stirring; then the compound shown in Formula I (specifically compound 2) is added for the second stirring; the mixture is filtered, and the resulting solid is washed and dried to obtain the modified magnesium hydroxide; wherein the weight ratio of the magnesium hydroxide, the compound shown in Formula I, the silane coupling agent, and the alcohol-water mixture is 100:7:3:400; the operating conditions for the first stirring include a temperature of 40℃ and a time of 60 min; the operating conditions for the second stirring include a temperature of 50℃ and a time of 90 min. The chemical structure of compound 2 is shown below: ; Based on 100 parts by weight of the polyolefin composition, the flame retardant is added in the amount of 10 parts by weight and the additive is added in the amount of 2.5 parts by weight, the additive being composed of a lubricant (specifically polyethylene wax, 1 part) and an antioxidant (specifically antioxidant 1010, 1.5 parts).

[0023] The preparation method of the above flame-retardant cable sheath material is the same as that in Example 1.

[0024] Example 3 This example provides a flame-retardant cable sheath material, including a polyolefin composition, a flame retardant, and additives; The polyolefin composition is composed of high-density polyethylene (product model HSGC7260) and low-density polyethylene (product model DJ210), with the weight ratio of high-density polyethylene to low-density polyethylene being 75:25. The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 5.8:1. The preparation of the modified magnesium hydroxide includes the following process: magnesium hydroxide (particle size of 2µm) and a silane coupling agent (specifically KH-550, γ-aminopropyltriethoxysilane) are added to an alcohol-water mixture (ethanol and water in a volume ratio of 4:1, with the pH adjusted to 4.5 by adding an appropriate amount of glacial acetic acid) for the first stirring; then the compound shown in Formula I (specifically compound 1) is added for the second stirring; the mixture is filtered, and the resulting solid is washed and dried to obtain the modified magnesium hydroxide; wherein the weight ratio of the magnesium hydroxide, the compound shown in Formula I, the silane coupling agent, and the alcohol-water mixture is 100:10:5.7:500; the operating conditions for the first stirring include a temperature of 45℃ and a time of 35 min; the operating conditions for the second stirring include a temperature of 45℃ and a time of 110 min. The chemical structure of compound 1 is shown below: ; Based on 100 parts by weight of the polyolefin composition, the flame retardant is added in the amount of 14 parts by weight and the additive is added in the amount of 4 parts by weight, the additive being composed of a lubricant (specifically polyethylene wax, 2 parts) and an antioxidant (specifically antioxidant 1010, 2 parts).

[0025] The preparation method of the above flame-retardant cable sheath material is the same as that in Example 1.

[0026] Comparative Example 1 This example provides a flame-retardant cable sheath material and its preparation method, which differs from Example 1 only in that: (1) Compound 1 was modified to Compound 3 (i.e., magnesium hydroxide was modified using an asymmetric indenamine compound); the chemical structure of Compound 3 is shown below: .

[0027] Comparative Example 2 This example provides a flame-retardant cable sheath material and its preparation method, which differs from Example 1 only in that: (1) The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 1:4.7 (i.e., the ratio of modified magnesium hydroxide and DOPO is adjusted so that the flame retardant is mainly composed of DOPO).

[0028] Test case This example demonstrates the performance testing of the flame-retardant cable sheath materials obtained from the above embodiments and comparative examples.

[0029] The testing methods include: 1) The oxygen index (OI, %) was tested in accordance with the GB / T 2406.2-2009 test standard; 2) Tensile strength (MPa) was tested in accordance with the ISO 527-1:2019 test standard.

[0030] The test results are shown in Table 1.

[0031] Table 1 As shown in Table 1: 1) The oxygen index of the flame-retardant cable sheath material provided in this embodiment of the invention is maintained at 34.2%-42.9%, which meets the Class A requirement (oxygen index ≥32%) in the "Classification of Combustion Performance of Cables and Optical Cables", and has excellent mechanical properties.

[0032] 2) The test results of Example 1, Comparative Example 1 and Comparative Example 2 show that if asymmetric indanediamine compounds are used to modify magnesium hydroxide or the ratio of modified magnesium hydroxide to DOPO is adjusted, the flame retardant properties and mechanical properties of the resulting material will be significantly reduced.

[0033] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0034] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A flame-retardant cable sheath material, characterized in that, Includes polyolefin compositions, flame retardants, and additives; The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of (3.5-5.8):

1. The modified magnesium hydroxide is obtained by modifying magnesium hydroxide as a raw material with the compound shown in Formula I. Equation I: R1, R2, R3, and R4 are each independently hydroxyl and amino groups.

2. The flame-retardant cable sheath material according to claim 1, characterized in that, The compound represented by Formula I includes at least one of compound 1 and compound 2; The chemical structure of compound 1 is shown below: ; The chemical structure of compound 2 is shown below: .

3. The flame-retardant cable sheath material according to claim 1, characterized in that, The flame retardant is composed of modified magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a weight ratio of 4.7:

1.

4. The flame-retardant cable sheath material according to claim 1, characterized in that, The preparation of the modified magnesium hydroxide includes the following process: The magnesium hydroxide and silane coupling agent were added to an alcohol-water mixture of ethanol and water and stirred for the first time. Then, the compound shown in Formula I was added and stirred for the second time. The mixture was filtered and the resulting solid was washed and dried to obtain the modified magnesium hydroxide. The weight ratio of the magnesium hydroxide, the compound shown in Formula I, the silane coupling agent, and the alcohol-water mixed solution is 100:(7-12):(3-6):(400-500); the working conditions of the first stirring include: temperature of 40-50℃ and time of 30-60min; the working conditions of the second stirring include: temperature of 40-50℃ and time of 90-120min.

5. The flame-retardant cable sheath material according to any one of claims 1-4, characterized in that, The flame retardant is added in 10-15 parts by weight per 100 parts by weight of the polyolefin composition.

6. The flame-retardant cable sheath material according to claim 5, characterized in that, The amount of the additive added is 1-5 parts by weight, based on 100 parts by weight of the polyolefin composition.

7. The flame-retardant cable sheath material according to claim 6, characterized in that, The additives include at least one of lubricant and antioxidant; the lubricant includes polyethylene wax, and the antioxidant includes antioxidant 1010.

8. The flame-retardant cable sheath material according to claim 7, characterized in that, The polyolefin composition is composed of materials with a density of 0.941-0.960 g / cm³. 3 High-density polyethylene with a density of 0.910-0.925 g / cm³ 3 It is composed of low-density polyethylene, wherein the weight ratio of high-density polyethylene to low-density polyethylene is (70-75):(25-30).

9. A method for preparing the flame-retardant cable sheath material according to any one of claims 1-8, characterized in that, Includes the following steps: The raw materials are then thoroughly mixed to obtain a mixture. The mixture is melt-extruded and granulated to obtain the flame-retardant cable sheath material.

10. The method for preparing the flame-retardant cable sheath material according to claim 9, characterized in that, The mixing temperature is 155-160℃, and the melt extrusion temperature is 165-170℃.

Images