High-flame-retardant cable sheath material and preparation method thereof

Abstract

The invention relates to a high-flame-retardant cable sheath material and a preparation method thereof, and belongs to the technical field of high polymer materials. The high-flame-retardant cable sheath material is prepared from the high-density polyethylene, the ethylene-vinyl acetate copolymer, the initiator, the antioxidant, the carbon black and the self-made reactive flame retardant, and the reactive flame retardant is relatively low in polarity, has reactive double bonds, can be grafted in a polymer molecular chain under the action of the initiator, and can be used for preparing the high-flame-retardant cable sheath material. The reactive flame retardant has good compatibility with a polyolefin cable sheath base material, the mechanical property and the dielectric property of the cable sheath cannot be reduced by using the reactive flame retardant, in addition, the reactive flame retardant can simultaneously exert multiple flame retardant mechanisms, the flame retardant property of the cable sheath is effectively improved, and the service life of the cable sheath is prolonged. And dripping and toxic smoke generation do not occur in flames.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular, relates to a cable sheathing material, and more particularly, to a highly flame-retardant cable sheathing material and a preparation method thereof. Background Art

[0002] Flame retardancy is crucial to the safety performance of cables. Good flame retardancy can effectively reduce the impact of fire on communication facilities and reduce the economic losses caused by fire accidents. Halogen flame retardants have the advantages of low addition amount and fast fire response, but they will release toxic gases during combustion, which endangers people's health and safety and increases the difficulty of fire rescue. Therefore, environmental protection regulations in various countries are increasingly stringent on them. Phosphorus-based flame retardants have the advantages of safety, non-toxicity and environmental protection. They can achieve good flame retardant effects by compounding with nitrogen-based flame retardants and silicon-based flame retardants, and will not drip or produce toxic smoke during combustion. However, in order to achieve the ideal flame retardant effect, phosphorus-based flame retardants require a large addition amount, and phosphorus-based flame retardants themselves have a large polarity, so they are not compatible with polyolefin cables. Adding a large amount of flame retardants may cause phase separation problems due to interface differences, seriously affecting the mechanical properties of the material.

[0003] The dielectric constant can reflect the insulation reliability and anti-interference ability of the cable sheath. The lower the dielectric constant, the lower the signal attenuation and the longer the transmission distance. The dielectric constant of conventional polyolefin cables is 2.3-2.4, which can meet the needs of high-frequency use. However, after adding a large amount of polar flame retardants, the dielectric constant of the cable will increase significantly due to the induced polarization effect of the polar groups on the dipoles, which may lead to abnormal electromagnetic wave reflection / absorption. In order to solve the above technical defects, the present invention prepares a highly flame-retardant cable sheath material by inventing a reactive flame retardant with good compatibility. Summary of the Invention

[0004] The object of the present invention is to provide a highly flame-retardant cable sheath material and a preparation method thereof, so as to solve the problems mentioned in the above background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 75-85 parts of high-density polyethylene, 15-25 parts of ethylene-vinyl acetate copolymer, 0.07-0.08 parts of initiator, 0.2-0.4 parts of antioxidant, 2-3 parts of carbon black, and 14-16 parts of reactive flame retardant;

[0007] Furthermore, the initiator is diisopropyl peroxide.

[0008] Furthermore, the antioxidant is a mixture of any one or more of antioxidant 1010 and antioxidant 1035.

[0009] Furthermore, the carbon black is channel black.

[0010] Furthermore, the reactive flame retardant is prepared by the following steps:

[0011] S1. Mix silane coupling agent KH-550, vinylphosphonyl chloride, triethylamine, and tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, start magnetic stirring, and react at a temperature of 20-40°C for 4-6 hours. After the reaction is completed, filter and separate the solid, and remove low-boiling-point substances by rotary evaporation of the remaining liquid to obtain a silicon-phosphorus flame retardant;

[0012] S2. Mix silicon-phosphorus flame retardant, boric acid, dilute hydrochloric acid and tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, start magnetic stirring, and react at a temperature of 50-70°C for 8-12 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the remaining solid with anhydrous ethanol and dry it to obtain a reactive flame retardant.

[0013] Furthermore, the mass ratio of silane coupling agent KH-550, vinylphosphonyl chloride, triethylamine and tetrahydrofuran used in S1 is 20-22:6-7:9-12:60-100.

[0014] Furthermore, the concentration of the dilute hydrochloric acid used in S2 is 0.1 to 2 mol / L.

[0015] Furthermore, the mass ratio of the silicon-phosphorus flame retardant, boric acid, dilute hydrochloric acid, and tetrahydrofuran used in S2 is 18-24:1.5-2.0:10-20:40-70.

[0016] The invention also discloses a preparation method of the highly flame-retardant cable sheath material.

[0017] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0018] Under inert gas protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black and reactive flame retardant are added into a twin-screw extruder for melt extrusion and granulation to obtain a highly flame-retardant cable sheath material.

[0019] Furthermore, the inert gas is one of nitrogen and argon.

[0020] Furthermore, the temperature condition of melt extrusion is 175-185°C.

[0021] Beneficial effects of the present invention:

[0022] 1) The present invention uses a silane coupling agent KH-550 and vinylphosphonyl chloride as raw materials, utilizes the amino group of the silane coupling agent KH-550 to undergo a nucleophilic substitution reaction with the acyl chloride group of vinylphosphonyl chloride to obtain a silicon-phosphorus flame retardant, and then utilizes the silicon-oxygen bond of the silicon-phosphorus flame retardant to undergo a condensation reaction with the hydroxyl group of boric acid to obtain a reactive flame retardant. The present invention introduces a reactive double bond into the reactive flame retardant through vinylphosphonyl chloride, which can be grafted into the polyethylene molecular chain under the action of an initiator, diisophenylene peroxide, thereby improving the compatibility of the reactive flame retardant of the present invention with high-density polyethylene, avoiding the problem of phase separation, and thereby improving the tensile strength and impact toughness of the material.

[0023] 2) The reactive flame retardant of the present invention is a macromolecular polymer containing phosphorus, nitrogen, silicon, and boron elements, which can simultaneously exert multiple flame retardant mechanisms. Compared with the addition of various flame retardants separately, the reactive flame retardant of the present invention has better dispersion between the elemental components, can better exert a synergistic flame retardant effect, and will not produce interface defects due to the polarity differences of the flame retardants of each component.

[0024] 3) The structure of the reactive flame retardant of the present invention is mainly a flexible chain segment of a borosiloxane polymer. The molecular chain contains a small number of polar functional groups and does not contain an aromatic ring. Not only does it not induce dipole polarization, but it can also utilize the strong mobility and large free volume of the flexible chain segment to make it difficult for the dipoles to be oriented, thereby suppressing the electronic polarization effect of the material, reducing the dielectric constant of the material, and improving the dielectric properties of the material. DETAILED DESCRIPTION

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0026] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0027] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0028] As used herein, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0029] In this document, when referring to a range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same. For example, 40-80°C means that the units of both the left endpoint "40" and the right endpoint "80" are °C.

[0030] Only certain numerical ranges are specifically disclosed herein. However, any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and similarly, any upper limit may be combined with any other upper limit to form an unspecified range. In addition, each individually disclosed point or single value may itself serve as a lower limit or upper limit and be combined with any other point or single value, or with other lower limits or upper limits, to form an unspecified range.

[0031] Example 1

[0032] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 75 parts of high-density polyethylene, 25 parts of ethylene-vinyl acetate copolymer, 0.07 parts of initiator, 0.2 parts of antioxidant, 2 parts of carbon black, and 14 parts of reactive flame retardant;

[0033] The initiator is diisopropyl peroxide, the antioxidant is antioxidant 1010, the carbon black is channel black, and the reactive flame retardant is prepared by the following steps:

[0034] S1. Mix 20 parts by mass of silane coupling agent KH-550, 6 parts of vinylphosphonyl chloride, 9 parts of triethylamine, and 60 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at 20°C for 6 hours. After the reaction is completed, filter and separate the solid, and evaporate the remaining liquid to remove low-boiling point substances to obtain a silicon-phosphorus flame retardant;

[0035] S2. Mix 18 parts of silicon-phosphorus flame retardant, 1.5 parts of boric acid, 20 parts of dilute hydrochloric acid with a concentration of 0.1 mol / L, and 40 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at a temperature of 70°C for 8 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the remaining solid with anhydrous ethanol, and then dry to obtain a reactive flame retardant.

[0036] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0037] Under nitrogen protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black, and reactive flame retardant are added into a twin-screw extruder and melt-extruded and granulated at a temperature of 175°C to obtain a highly flame-retardant cable sheath material.

[0038] Example 2

[0039] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 80 parts of high-density polyethylene, 20 parts of ethylene-vinyl acetate copolymer, 0.075 parts of initiator, 0.3 parts of antioxidant, 2.5 parts of carbon black, and 15 parts of reactive flame retardant;

[0040] The initiator is diisopropyl peroxide, the antioxidant is antioxidant 1010, the carbon black is channel black, and the reactive flame retardant is prepared by the following steps:

[0041] S1. Mix 21 parts of silane coupling agent KH-550, 6.5 parts of vinylphosphonyl chloride, 10.5 parts of triethylamine, and 80 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at 30°C for 5 hours. After the reaction is completed, filter and separate the solid, and remove low-boiling-point substances by rotary evaporation of the remaining liquid to obtain a silicon-phosphorus flame retardant;

[0042] S2. Mix 21 parts of silicon-phosphorus flame retardant, 1.75 parts of boric acid, 15 parts of dilute hydrochloric acid with a concentration of 1 mol / L, and 55 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at a temperature of 60°C for 10 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the remaining solid with anhydrous ethanol, and then dry to obtain a reactive flame retardant.

[0043] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0044] Under nitrogen protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black, and reactive flame retardant are added into a twin-screw extruder and melt-extruded and granulated at a temperature of 180°C to obtain a highly flame-retardant cable sheath material.

[0045] Example 3

[0046] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 85 parts of high-density polyethylene, 15 parts of ethylene-vinyl acetate copolymer, 0.08 parts of initiator, 0.4 parts of antioxidant, 3 parts of carbon black, and 16 parts of reactive flame retardant;

[0047] The initiator is diisopropyl peroxide, the antioxidant is antioxidant 1035, the carbon black is channel black, and the reactive flame retardant is prepared by the following steps:

[0048] S1. Mix 22 parts by mass of silane coupling agent KH-550, 7 parts of vinylphosphonyl chloride, 12 parts of triethylamine, and 100 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at 40°C for 4 hours. After the reaction is completed, filter and separate the solid, and remove low-boiling-point substances by rotary evaporation of the remaining liquid to obtain a silicon-phosphorus flame retardant;

[0049] S2. Mix 24 parts of silicon-phosphorus flame retardant, 2 parts of boric acid, 10 parts of 2 mol / L dilute hydrochloric acid, and 70 parts of tetrahydrofuran in a three-necked flask, install a condenser and a thermometer, turn on magnetic stirring, and react at 50°C for 12 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash the remaining solid with anhydrous ethanol, and then dry to obtain a reactive flame retardant.

[0050] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0051] Under argon protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant and carbon black are added into a twin-screw extruder and melt-extruded and granulated at a temperature of 185°C to obtain a highly flame-retardant cable sheath material.

[0052] Comparative Example 1

[0053] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 85 parts of high-density polyethylene, 15 parts of ethylene-vinyl acetate copolymer, 0.4 parts of antioxidant, 3 parts of carbon black, and 16 parts of flame retardant;

[0054] Among them, the antioxidant is antioxidant 1035, the carbon black is channel carbon black, the flame retardant is ammonium polyphosphate, polysiloxane, and triethyl borate, and the mass ratio of ammonium polyphosphate, polysiloxane, and triethyl borate is 13:2:1.

[0055] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0056] Under argon protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black and flame retardant are added into a twin-screw extruder and melt-extruded and granulated at a temperature of 185°C to obtain a highly flame-retardant cable sheath material.

[0057] Comparative Example 2

[0058] A highly flame-retardant cable sheath material, comprising the following raw materials in parts by weight: 85 parts of high-density polyethylene, 15 parts of ethylene-vinyl acetate copolymer, 0.4 parts of an antioxidant, and 3 parts of carbon black;

[0059] Wherein, the antioxidant is antioxidant 1035, and the carbon black is channel black.

[0060] A method for preparing a highly flame-retardant cable sheath material comprises the following steps:

[0061] Under argon protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black, and reactive flame retardant are added into a twin-screw extruder and melt-extruded and granulated at a temperature of 185°C to obtain a highly flame-retardant cable sheath material.

[0062] Experimental example

[0063] The cable sheath materials in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to performance tests, tensile performance tests were performed in accordance with the national standard GB / T13849.1-2013, and oxygen limiting index tests were performed in accordance with the national standard GB / T2406.2-2009. The dielectric constants of the cable sheath materials of each component were tested using dielectric and impedance spectrometers. The test results are shown in Table 1:

[0064] Table 1

[0065]

[0066] It can be seen from Table 1 that the highly flame-retardant cable sheath material of the present invention in Examples 1 to 3 can maintain good tensile properties and a low dielectric constant while having good flame retardancy. It can be seen from Comparative Examples 1 and 2 that not using the reactive flame retardant of the present invention but adding a small molecule flame retardant alone not only fails to achieve a good flame retardant effect, but also seriously affects the mechanical properties and dielectric properties of the material.

[0067] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A highly flame-retardant cable sheath material, characterized in that: The invention comprises the following raw materials in parts by weight: 75 to 85 parts of high-density polyethylene, 15 to 25 parts of ethylene-vinyl acetate copolymer, 0.07 to 0.08 parts of initiator, 0.2 to 0.4 parts of antioxidant, 2 to 3 parts of carbon black, and 14 to 16 parts of reactive flame retardant; Wherein, the reactive flame retardant is prepared by the following steps: Silane coupling agent KH-550, vinylphosphonyl chloride and triethylamine are dissolved in tetrahydrofuran and then reacted at a temperature of 20-40°C to obtain a silicon-phosphorus flame retardant. The obtained silicon-phosphorus flame retardant is then dissolved together with boric acid and dilute hydrochloric acid in tetrahydrofuran and then reacted at a temperature of 50-70°C to obtain a reactive flame retardant.

2. A highly flame-retardant cable sheath material according to claim 1, characterized in that: The initiator is diisophenylpropane peroxide.

3. The highly flame-retardant cable sheath material according to claim 1, characterized in that: The antioxidant is a mixture of any one or more of antioxidant 1010 and antioxidant 1035.

4. A highly flame-retardant cable sheath material according to claim 1, characterized in that: The carbon black is channel black.

5. The highly flame-retardant cable sheath material according to claim 1, characterized in that: The mass ratio of silane coupling agent KH-550, vinylphosphonyl chloride and triethylamine is 20-22:6-7:9-12.

6. The highly flame-retardant cable sheath material according to claim 1, characterized in that: The concentration of dilute hydrochloric acid is 0.1~2mol / L.

7. The highly flame-retardant cable sheath material according to claim 1, characterized in that: The mass ratio of silicon-phosphorus flame retardant, boric acid and dilute hydrochloric acid is 18-24:1.5-2.0:10-20.

8. A method for preparing a highly flame-retardant cable sheath material as claimed in any of claims 1 to 7, characterized in that: The following steps are involved: Under inert gas protection conditions, high-density polyethylene, ethylene-vinyl acetate copolymer, initiator, antioxidant, carbon black and reactive flame retardant are added into a twin-screw extruder for melt extrusion and granulation to obtain a highly flame-retardant cable sheath material.

9. The method for preparing a highly flame-retardant cable sheath material according to claim 8, characterized in that: The inert gas is one of nitrogen and argon.

10. The method for preparing a highly flame-retardant cable sheath material according to claim 8, characterized in that: The temperature condition for melt extrusion is 175 to 185°C.

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