A low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience and its preparation method

Abstract

The present invention relates to the technical field of sheath materials, in particular to a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience and a preparation method thereof. Step 1: Add O-type silica sol into an ethanol aqueous solution of 20-30 wt%, stir evenly, add borosilane, heat up to 60-65 °C and stir for 6-8 hours, and dry to obtain a flame-retardant release agent; Step 2: Add ammonium polyphosphate flame retardant, polyurethane prepolymer, and catalyst into tetrahydrofuran in sequence, heat up to 70-90 °C and stir for 1.5-2.5 hours; evaporate the solvent at 45-50 °C to obtain a polyurethane elastomer; Step 3: Mix low-density polyethylene, ethylene-vinyl acetate, polyurethane elastomer, flame-retardant release agent, compatibilizer, and antioxidant evenly, and melt-extrude to obtain masterbatch; Knead and press the masterbatch to obtain the low-smoke and halogen-free optical cable sheath material.

Description

Technical Field

[0001] The present invention relates to the technical field of optical cable sheath materials, and specifically to a low-smoke and halogen-free optical cable sheath material with easy peeling and high resilience and a preparation method thereof. Background Art

[0002] In the communication industry, as an important medium for transmitting information, the performance of optical cables is directly related to the stability and security of communication. Among them, the optical cable sheath material is a key material for protecting the optical cable from external influences and has an important impact on the service life of optical fibers and their shielding layers. At present, in the performance trend of optical fiber sheath materials, first, it is necessary to have high resilience and mechanical properties, which can effectively buffer the effects of external impacts and thus effectively improve the protection; second, it is necessary to have easy peeling performance, which is convenient for installation and reduces damage during installation; third, it is necessary to have low-smoke and halogen-free properties. Traditional PVC-based sheath materials produce toxic smoke when burned, which is harmful to the environment and human health.

[0003] In the prior art, elastomers, release agents, and flame retardants are usually used to increase the high resilience of optical fiber sheath materials. However, in general sheath materials, the introduction of substances such as elastomers reduces the compatibility, which will affect the interfacial action and rheological properties and is not conducive to the increase of resilience and mechanical properties. On the other hand, although flame retardants are introduced, due to the decrease in crosslinking degree, the flame retardant performance cannot be maximized.

[0004] In summary, to solve the above problems, it is of great significance to prepare a low-smoke and halogen-free optical cable sheath material with easy peeling and high resilience. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-smoke and halogen-free optical cable sheath material with easy peeling and high resilience and a preparation method thereof to solve the problems proposed in the above background art.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] A preparation method of a low-smoke and halogen-free optical cable sheath material with easy peeling and high resilience includes the following steps:

[0008] Step 1: (1) Dissolve boric acid in isopropanol, add vinyltriethoxysilane and 3-aminopropyltriethoxysilane, stir at room temperature for 8-10 hours; adjust the pH = 8-10, continue to stir for 0.5-1.5 hours, filter, wash, and dry to obtain boron-based silane; (2) Add O-type silica sol to a 20-30 wt% ethanol aqueous solution, stir evenly, add boron-based silane, heat to 60-65 °C, stir for 6-8 hours, and dry to obtain a flame retardant release agent;

[0009] Step 2: Add ammonium polyphosphate flame retardant, polyurethane prepolymer, and catalyst into tetrahydrofuran in sequence, heat up to 70 - 90 °C and stir for 1.5 - 2.5 hours; evaporate the solvent at 45 - 50 °C to obtain polyurethane elastomer;

[0010] Step 3: Mix low-density polyethylene, ethylene vinyl acetate, polyurethane elastomer, flame retardant release agent, compatibilizer, and antioxidant evenly, and perform melt extrusion to obtain masterbatch; open mill and press the masterbatch to obtain low-smoke and halogen-free cable sheath material.

[0011] Preferably, the raw materials of the low-smoke and halogen-free cable sheath material include the following components: by weight, 42 - 45 parts of low-density polyethylene, 5 - 8 parts of ethylene vinyl acetate, 28 - 32 parts of polyurethane elastomer, 10 - 13 parts of flame retardant release agent, 8 - 9 parts of compatibilizer, and 0.5 - 1 part of antioxidant.

[0012] Preferably, the melt extrusion temperature is 140 - 150 °C, the rotation speed is 150 - 200 rpm; the open mill temperature is 130 - 140 °C; the pressing temperature is 160 - 170 °C, the pressure is 15 - 18 Mpa, and the pressing time is 5 - 10 min.

[0013] Preferably, the raw materials of the boron-based silane include the following components: by weight, 4.5 - 5.5 parts of boric acid, 120 - 150 parts of isopropanol, 4 - 6 parts of vinyltriethoxysilane, and 8 - 10 parts of 3-aminopropyltriethoxysilane;

[0014] The raw materials of the flame retardant release agent include O-type silica sol and boron-based silane with a mass ratio of 1:0.03 - 0.05, and the solid content of the O-type silica sol is 20 - 22 wt%.

[0015] Preferably, in the raw materials of the polyurethane elastomer, the ammonium polyphosphate flame retardant accounts for 8 - 10 wt% of the mass of the polyurethane prepolymer.

[0016] Preferably, the preparation method of the ammonium polyphosphate flame retardant is: (1) Under a nitrogen atmosphere, add ammonium polyphosphate and polyethyleneimine into an ethanol aqueous solution of 95 - 98 wt% in sequence, heat up to 75 - 80 °C and stir for 4 - 6 hours, filter and dry to obtain an intermediate product; (2) Add Tri-buffer solution into an ethanol aqueous solution of 90 - 92 wt%, with a concentration of 0.2 - 0.3 g / mL; adjust the pH = 8 - 9 using sodium hydroxide solution; add tannic acid and hydrogen peroxide and stir evenly, add the intermediate product, and stir at 30 - 35 °C for 5 - 6 hours, filter and dry to obtain ammonium polyphosphate flame retardant.

[0017] Preferably, the raw materials of the ammonium polyphosphate flame retardant include the following components: by weight, 10 parts of ammonium polyphosphate, 5-7 parts of polyethyleneimine, 8-10 parts of tannic acid, and 0.2-0.3 parts of hydrogen peroxide.

[0018] Preferably, the compatibilizer includes polyethylene-polyurethane-polyethylene and maleic anhydride grafted polyethylene with a mass ratio of 1.2-1.5:0.5-0.8.

[0019] Preferably, the preparation method of the polyethylene-polyurethane-polyethylene is as follows: (1) Low-density polyethylene and 2-mercaptoethanol with a mass ratio of 1:1.1-1.2 are sequentially added to toluene, initiator AIBN is added, and the temperature is raised to 105-110°C and stirred for 5-6 hours, washed and dried to obtain hydroxylated polyethylene; (2) Hydroxylated polyethylene and polyurethane prepolymer with a mass ratio of 1:2-3 are sequentially added to toluene, a catalyst is added, and stirred at 100-105°C for 1-2 hours, washed and dried to obtain polyethylene-polyurethane-polyethylene.

[0020] Preferably, a low-smoke and halogen-free optical cable sheath material prepared by the preparation method of an easily peelable and highly elastic low-smoke and halogen-free optical cable sheath material.

[0021] Compared with the prior art, the beneficial effects of the present application are as follows:

[0022] In the solution, an elastomer is introduced to improve the resilience performance; among them, ethylene vinyl acetate is a material with resilience performance, but it has high adhesiveness, and introducing too much will increase the peelability. Therefore, a polyurethane elastomer with high strength and high toughness is used as the main elastic material in the solution. The introduction of polyurethane can increase the crosslinking density of the optical cable sheath material, thereby increasing cohesion, effectively improving mechanical properties such as resilience, and ensuring the easy peelability. On the other hand, the combination of polyurethane and ethylene vinyl acetate makes the optical cable sheath material maintain softness and enhances mechanical properties such as impact resistance, improves environmental stress cracking resistance, and increases the long-term stability and reliability of optical cable applications in different environments.

[0023] In the solution, the polyurethane elastomer is prepared by reacting an ammonium polyphosphate flame retardant and a polyurethane prepolymer E95C; and the ammonium polyphosphate flame retardant forms an intumescent flame retardancy by pre-coating with polyethyleneimine and tannic acid. Compared with directly introducing ammonium polyphosphate, after coating, the increase in the residual carbon amount and carbon strength during the pyrolysis process effectively inhibits the emission of toxic and harmful gases, forms a thermal barrier, thereby effectively improving the flame retardancy and improving the low-smoke performance. At the same time, the coating is used to effectively improve the interfacial property of its composite with the polyurethane elastomer and enhance its dispersibility in the optical cable sheath material.

[0024] In the solution, in order to improve the easy peeling performance and further increase the flame retardant performance, silica in the O-type silica sol is used as an inorganic anti-sticking agent, and it is modified on its surface by boron-based silane containing boron to reduce the force between the sheath material and the optical fiber, serving as an organic anti-sticking agent, thereby effectively improving the easy peeling property. On the other hand, silica and boron elements can effectively improve the flame retardancy and also reduce the smoke generation amount of the material during the pyrolysis process, improving the low-smoke performance. At the same time, boron-based silane can also improve its dispersibility in the optical cable sheath material, and a small amount of vinyl silane coupling agent is introduced into the boron-based silane, which can be partially cross-linked in and on the surface of the optical cable sheath material to improve the durability.

[0025] In the solution, since the polyurethane elastomer contains ammonium polyphosphate flame retardant, the elastic performance of the polyurethane elastomer will be weakened, so ethylene vinyl acetate is used to cooperate with it to improve the resilience. On the other hand, in the solution, polyethylene-polyurethane-polyethylene containing polyurethane segments is prepared to assist in improving the elasticity. At the same time, this polyethylene-polyurethane-polyethylene is prepared from low-density polyethylene and polyurethane prepolymer, and the raw materials have excellent similar compatibility, so as a compatibilizer, it effectively enhances the interfacial interaction between substances, improves the mechanical properties, and at the same time increases the chain segment entanglement and crosslinking, improves the cohesion, and thus enhances the easy peeling performance.

[0026] In summary, this application is mainly based on low-density polyethylene, and improves the resilience by introducing ethylene vinyl acetate and polyurethane elastomer; effectively enhances the easy peeling property by introducing a flame retardant and peeling agent; at the same time, effectively improves the flame retardant performance of the optical cable sheath material by introducing ammonium polyphosphate flame retardant into polyurethane and cooperating with the flame retardant and peeling agent; and effectively improves the interfacial interaction and crosslinking by introducing a compatibilizer including polyethylene-polyurethane-polyethylene, thereby effectively maximizing the mechanical properties and flame retardant performance of the optical cable sheath material. Detailed implementation manners

[0027] Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0028] It should be noted that the following parts are parts by mass; there are no special restrictions on the purchase manufacturers of all raw materials involved in the present invention. Exemplarily, the model of the low-density polyethylene is 1050B, and the brand is DowDuPont; the model of the polyethylene grafted maleic anhydride is E158, and the brand is DuPont; the solid content of the O-type silica sol is 20 wt%; the model of the polyurethane prepolymer is E95C, purchased from Shanghai Jiren International; the rest of the raw materials are commercially available.

[0029] The preparation method of ammonium polyphosphate flame retardant is as follows: (1) Under a nitrogen atmosphere, 10 parts of ammonium polyphosphate and 6 parts of polyethyleneimine are successively added to an ethanol aqueous solution with a concentration of 95 wt%, and the temperature is raised to 80 °C and stirred for 5 hours. After filtration and drying, an intermediate product is obtained; (2) Tri-buffer solution is added to an ethanol aqueous solution with a concentration of 90 wt%, and the concentration is 0.2 g / mL; the pH is adjusted to 8.6 using sodium hydroxide solution; 10 parts of tannic acid and 0.25 parts of hydrogen peroxide are added and stirred evenly, then the intermediate product is added, and the mixture is stirred at 30 °C for 6 hours. After filtration and drying, ammonium polyphosphate flame retardant is obtained.

[0030] The preparation method of the polyethylene-polyurethane-polyethylene is as follows: (1) 10 parts of low-density polyethylene and 12 parts of 2-mercaptoethanol are successively added to toluene, 0.05 parts of initiator AIBN is added, and the temperature is raised to 110 °C and stirred for 6 hours. After washing and drying, hydroxylated polyethylene is obtained; (2) 10 parts of hydroxylated polyethylene and 22 parts of polyurethane prepolymer are successively added to toluene, 0.02 parts of organotin catalyst MT9001 is added, and the mixture is stirred at 105 °C for 2 hours. After washing and drying, polyethylene-polyurethane-polyethylene is obtained.

[0031] Example 1: A preparation method of a low-smoke and halogen-free cable sheath material with easy peelability and high resilience includes the following steps:

[0032] Step 1: (1) 5 parts of boric acid is dissolved in 150 parts of isopropanol, 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane are added, and the mixture is stirred at room temperature for 10 hours; the pH is adjusted to 9.1, and stirring is continued for 1 hour. After filtration, washing and drying, borosilane is obtained; (2) 10 parts of O-type silica sol is added to an ethanol aqueous solution with a concentration of 20 wt% and stirred evenly, 0.4 parts of borosilane is added, and the temperature is raised to 60 °C and stirred for 6 hours. After drying, a flame-retardant release agent is obtained;

[0033] Step 2: 0.8 parts of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 parts of organotin catalyst MT9001 are successively added to 100 parts of tetrahydrofuran, and the temperature is raised to 90 °C and stirred for 2 hours; the solvent is evaporated at 45 °C to obtain a polyurethane elastomer;

[0034] Step 3: 44 parts of low-density polyethylene, 6 parts of ethylene vinyl acetate, 30 parts of polyurethane elastomer, 11 parts of flame-retardant release agent, 9 parts of compatibilizer (a mixture of polyethylene-polyurethane-polyethylene and polyethylene grafted maleic anhydride with a mass ratio of 1.4:0.6), and 0.5 parts of antioxidant LOWINOX-CA22 are mixed evenly; the rotation speed is set to 200 rpm, and melt extrusion is carried out at 145 °C to obtain a masterbatch; the masterbatch is open-milled at 135 °C, and the temperature is set to 170 °C and the pressure is set to 15 Mpa for pressing for 6 min to form a sheet, and a low-smoke and halogen-free cable sheath material is obtained.

[0035] Example 2: A preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience, comprising the following steps:

[0036] Step 1: (1) Dissolve 5 parts of boric acid in 150 parts of isopropanol, add 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane, and stir at room temperature for 10 hours; adjust the pH to 9.1, continue stirring for 1 hour, filter, wash, and dry to obtain borosilane; (2) Add 10 parts of O-type silica sol to a 20 wt% ethanol aqueous solution, stir evenly, add 0.4 part of borosilane, heat up to 60 °C and stir for 6 hours, and dry to obtain a flame retardant release agent;

[0037] Step 2: Add 1 part of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 part of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat up to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain a polyurethane elastomer;

[0038] Step 3: Mix 42 parts of low-density polyethylene, 8 parts of ethylene vinyl acetate, 28 parts of polyurethane elastomer, 13 parts of flame retardant release agent, 9 parts of compatibilizer (polyethylene-polyurethane-polyethylene and polyethylene grafted maleic anhydride with a mass ratio of 1.2:0.8), and 0.5 part of antioxidant LOWINOX-CA22 evenly; set the rotation speed to 200 rpm, melt and extrude at 145 °C to obtain a masterbatch; open mill the masterbatch at 135 °C, set the temperature to 170 °C and the pressure to 15 Mpa, press for 6 min to form a sheet, and obtain the low-smoke and halogen-free optical cable sheath material.

[0039] Example 3: A preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience, comprising the following steps:

[0040] Step 1: (1) Dissolve 5 parts of boric acid in 150 parts of isopropanol, add 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane, and stir at room temperature for 10 hours; adjust the pH to 9.1, continue stirring for 1 hour, filter, wash, and dry to obtain borosilane; (2) Add 10 parts of O-type silica sol to a 20 wt% ethanol aqueous solution, stir evenly, add 0.4 part of borosilane, heat up to 60 °C and stir for 6 hours, and dry to obtain a flame retardant release agent;

[0041] Step 2: Add 0.8 part of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 part of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat up to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain a polyurethane elastomer;

[0042] Step 3: Mix 45 parts of low-density polyethylene, 5 parts of ethylene vinyl acetate, 32 parts of polyurethane elastomer, 10 parts of flame-retardant release agent, 8 parts of compatibilizer (polyethylene-polyurethane-polyethylene and polyethylene-grafted maleic anhydride with a mass ratio of 1.5:0.5), and 0.5 part of antioxidant LOWINOX-CA22 evenly; set the rotation speed at 200 rpm, and melt-extrude at 145 °C to obtain masterbatch; open mill the masterbatch at 135 °C, set the temperature at 170 °C and the pressure at 15 Mpa, press for 6 min to form a sheet, and obtain a low-smoke and halogen-free optical cable sheath material.

[0043] Comparative Example 1: Based on Example 1, adjust the preparation of polyurethane elastomer, and the rest is the same as Example 1; specifically as follows:

[0044] Step 1: (1) Dissolve 5 parts of boric acid in 150 parts of isopropanol, add 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane, stir at room temperature for 10 hours; adjust the pH = 9.1, continue to stir for 1 hour, filter, wash, and dry to obtain boron-based silane; (2) Add 10 parts of O-type silica sol to 20 wt% ethanol aqueous solution and stir evenly, add 0.4 part of boron-based silane, heat up to 60 °C and stir for 6 hours, and dry to obtain a flame-retardant release agent;

[0045] Step 2: Add 0.8 part of ammonium polyphosphate, 10 parts of polyurethane prepolymer E95C, and 0.02 part of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat up to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain polyurethane elastomer;

[0046] Step 3: Mix 44 parts of low-density polyethylene, 6 parts of ethylene vinyl acetate, 30 parts of polyurethane elastomer, 11 parts of flame-retardant release agent, 9 parts of compatibilizer (polyethylene-polyurethane-polyethylene and polyethylene-grafted maleic anhydride with a mass ratio of 1.4:0.6), and 0.5 part of antioxidant LOWINOX-CA22 evenly; set the rotation speed at 200 rpm, and melt-extrude at 145 °C to obtain masterbatch; open mill the masterbatch at 135 °C, set the temperature at 170 °C and the pressure at 15 Mpa, press for 6 min to form a sheet, and obtain a low-smoke and halogen-free optical cable sheath material.

[0047] Comparative Example 2: Based on Example 1, adjust the preparation of the flame-retardant release agent, and the rest is the same as Example 1; specifically as follows:

[0048] Step 1: Add 10 parts of O-type silica sol to 20 wt% ethanol aqueous solution and stir evenly, add 0.4 part of 3-aminopropyltriethoxysilane, heat up to 60 °C and stir for 6 hours, and dry to obtain a flame-retardant release agent;

[0049] Step 2: Add 0.8 parts of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 parts of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat up to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain polyurethane elastomer;

[0050] Step 3: Mix 44 parts of low-density polyethylene, 6 parts of ethylene vinyl acetate, 30 parts of polyurethane elastomer, 11 parts of flame-retardant release agent, 9 parts of compatibilizer (polyethylene-polyurethane-polyethylene and polyethylene-grafted maleic anhydride with a mass ratio of 1.4:0.6), and 0.5 part of antioxidant LOWINOX-CA22 evenly; set the rotation speed at 200 rpm, melt and extrude at 145 °C to obtain masterbatch; open mill the masterbatch at 135 °C, set the temperature at 170 °C and the pressure at 15 Mpa, press for 6 min to form sheets and obtain low-smoke and halogen-free optical cable sheath material.

[0051] Comparative Example 3: Based on Example 1, adjust the introduction amounts of ethylene vinyl acetate and polyurethane elastomer, and the rest is the same as Example 1; specifically as follows:

[0052] Step 1: (1) Dissolve 5 parts of boric acid in 150 parts of isopropanol, add 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane, stir at room temperature for 10 hours; adjust pH = 9.1, continue to stir for 1 hour, filter, wash, and dry to obtain boron-based silane; (2) Add 10 parts of O-type silica sol to 20wt% ethanol aqueous solution and stir evenly, add 0.4 part of boron-based silane, heat up to 60 °C and stir for 6 hours, and dry to obtain flame-retardant release agent;

[0053] Step 2: Add 0.8 parts of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 parts of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat up to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain polyurethane elastomer;

[0054] Step 3: Mix 44 parts of low-density polyethylene, 11 parts of ethylene vinyl acetate, 25 parts of polyurethane elastomer, 11 parts of flame-retardant release agent, 9 parts of compatibilizer (polyethylene-polyurethane-polyethylene and polyethylene-grafted maleic anhydride with a mass ratio of 1.4:0.6), and 0.5 part of antioxidant LOWINOX-CA22 evenly; set the rotation speed at 200 rpm, melt and extrude at 145 °C to obtain masterbatch; open mill the masterbatch at 135 °C, set the temperature at 170 °C and the pressure at 15 Mpa, press for 6 min to form sheets and obtain low-smoke and halogen-free optical cable sheath material.

[0055] Comparative Example 4: Based on Example 1, use polyethylene-grafted maleic anhydride alone, and the rest is the same as Example 1; specifically as follows:

[0056] Step 1: (1) Dissolve 5 parts of boric acid in 150 parts of isopropanol, add 5 parts of vinyltriethoxysilane and 10 parts of 3-aminopropyltriethoxysilane, and stir at room temperature for 10 hours; adjust the pH to 9.1, continue to stir for 1 hour, filter, wash, and dry to obtain borosilane; (2) Add 10 parts of O-type silica sol to an aqueous ethanol solution of 20 wt%, stir evenly, add 0.4 parts of borosilane, heat to 60 °C and stir for 6 hours, and dry to obtain a flame retardant release agent;

[0057] Step 2: Add 0.8 parts of ammonium polyphosphate flame retardant, 10 parts of polyurethane prepolymer E95C, and 0.02 parts of organotin catalyst MT9001 to 100 parts of tetrahydrofuran in sequence, heat to 90 °C and stir for 2 hours; evaporate the solvent at 45 °C to obtain a polyurethane elastomer;

[0058] Step 3: Mix 44 parts of low-density polyethylene, 6 parts of ethylene vinyl acetate, 30 parts of polyurethane elastomer, 11 parts of flame retardant release agent, 9 parts of polyethylene grafted maleic anhydride, and 0.5 parts of antioxidant LOWINOX-CA22 evenly; set the rotation speed to 200 rpm, and melt-extrude at 145 °C to obtain masterbatch; mill the masterbatch at 135 °C, set the temperature to 170 °C, the pressure to 15 Mpa, and press for 6 min to form sheets to obtain a low-smoke and halogen-free optical cable sheath material.

[0059] Performance Test 1: Conduct relevant performance tests on the low-smoke and halogen-free optical cable sheath materials in the examples and comparative examples. (1) Prepare a sample bar of 75 mm × 4 mm × 1 mm, use a universal tensile testing machine to test the tensile strength at a speed of 100 mm / min; (2) Prepare a sample bar of 100 mm × 10 mm × 4 mm, use an oxygen index meter to detect the limiting oxygen index; (3) The peel force test is detected using an optical fiber peel force at a rate of 25 mm / min; (4) The permanent deformation is hot-extended at a temperature of 200 °C, a pressure of 0.2 Mpa, and a time of 15 minutes, and then the permanent deformation rate after cooling is tested to evaluate the resilience. The obtained data are shown in the following table:

[0060] Spline Tensile strength / Mpa LOI / % Peeling force / N Permanent deformation rate after cooling / % Example 1 20.7 32.4 70 4.3 Comparative Example 1 18.0 28.9 72 10.1 Comparative Example 2 18.8 29.5 77 8.7 Comparative Example 3 20.3 30.2 81 5.9 Comparative Example 4 19.1 31.9 74 7.3

[0061] Conclusion: From the data in the above table, it can be seen that: In this application, a low-smoke and halogen-free optical cable sheath material was prepared. While introducing functional substances such as flame retardants, through effective modification methods and component ratio settings, on the basis of effectively ensuring the mechanical properties, the flame retardancy was enhanced. The comparison of the data of Comparative Examples 1-4 with the data of Example 1 shows that: directly introducing ammonium polyphosphate into the polyurethane elastomer affects the interfacial properties and flame retardancy, resulting in a decline in performance; using an amino silane coupling agent to replace the macromolecular boron-containing silane causes a decline in related properties; in addition, the ratio of ethylene vinyl acetate and polyurethane elastomer affects the interfacial properties of the substances, resulting in a decline in related properties; and using only polyethylene grafted maleic anhydride as a compatibilizer causes a decline in mechanical properties and resilience properties.

[0062] Finally, it should be noted that: The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience, characterized in that: It includes the following steps: Step 1: (1) Dissolve boric acid in isopropanol, add vinyltriethoxysilane and 3-aminopropyltriethoxysilane, and stir at room temperature for 8 - 10 hours; adjust the pH to 8 - 10, continue stirring for 0.5 - 1.5 hours, filter, wash, and dry to obtain borosilane; (2) Add O-type silica sol to an ethanol aqueous solution with a concentration of 20 - 30 wt%, stir evenly, add borosilane, heat up to 60 - 65 °C, stir for 6 - 8 hours, and dry to obtain a flame retardant release agent; Step 2: Add ammonium polyphosphate flame retardant, polyurethane prepolymer, and catalyst to tetrahydrofuran in sequence, heat up to 70 - 90 °C, and stir for 1.5 - 2.5 hours; evaporate the solvent at 45 - 50 °C to obtain a polyurethane elastomer; Step 3: Mix low-density polyethylene, ethylene vinyl acetate, polyurethane elastomer, flame retardant release agent, compatibilizer, and antioxidant evenly, and melt-extrude to obtain masterbatch; mill and press the masterbatch to obtain a low-smoke and halogen-free cable sheath material; The raw materials of the low-smoke and halogen-free cable sheath material include the following components: by weight, 42 - 45 parts of low-density polyethylene, 5 - 8 parts of ethylene vinyl acetate, 28 - 32 parts of polyurethane elastomer, 10 - 13 parts of flame retardant release agent, 8 - 9 parts of compatibilizer, and 0.5 - 1 part of antioxidant; The preparation method of the ammonium polyphosphate flame retardant is: (1) Under a nitrogen atmosphere, add ammonium polyphosphate and polyethyleneimine to an ethanol aqueous solution with a concentration of 95 - 98 wt% in sequence, heat up to 75 - 80 °C, and stir for 4 - 6 hours, filter and dry to obtain an intermediate product; (2) Add Tri-buffer solution to an ethanol aqueous solution with a concentration of 90 - 92 wt%, and the concentration is 0.2 - 0.3 g / mL; Use sodium hydroxide solution to adjust the pH to 8 - 9; add tannic acid and hydrogen peroxide, stir evenly, add the intermediate product, and stir at 30 - 35 °C for 5 - 6 hours, filter and dry to obtain ammonium polyphosphate flame retardant; The compatibilizer includes polyethylene-polyurethane-polyethylene and polyethylene grafted maleic anhydride with a mass ratio of 1.2 - 1.5:0.5 - 0.

8.

2. The preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience according to claim 1, wherein: The temperature of the melt extrusion is 140 - 150 °C, the rotation speed is 150 - 200 rpm; the milling temperature is 130 - 140 °C; the pressing temperature is 160 - 170 °C, the pressure is 15 - 18 Mpa, and the pressing time is 5 - 10 min.

3. The preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience according to claim 1, characterized in that: The raw materials of the borosilane include the following components: by weight, 4.5 - 5.5 parts of boric acid, 120 - 150 parts of isopropanol, 4 - 6 parts of vinyltriethoxysilane, and 8 - 10 parts of 3-aminopropyltriethoxysilane; The raw materials of the flame retardant release agent include O-type silica sol and borosilane with a mass ratio of 1:0.03 - 0.05, and the solid content of the O-type silica sol is 20 - 22 wt%.

4. The preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience according to claim 1, characterized in that: In the raw materials of the polyurethane elastomer, the ammonium polyphosphate flame retardant accounts for 8 - 10 wt% of the mass of the polyurethane prepolymer.

5. The preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience according to claim 1, characterized in that: The raw materials of the ammonium polyphosphate flame retardant include the following components: by weight, 10 parts of ammonium polyphosphate, 5 - 7 parts of polyethyleneimine, 8 - 10 parts of tannic acid, and 0.2 - 0.3 parts of hydrogen peroxide.

6. The preparation method of a low-smoke and halogen-free optical cable sheath material with easy peelability and high resilience according to claim 1, characterized in that: The preparation method of the polyethylene-polyurethane-polyethylene is as follows: (1) Low-density polyethylene and 2-mercaptoethanol with a mass ratio of 1:1.1-1.2 are sequentially added to toluene, initiator AIBN is added, the temperature is raised to 105-110°C, and stirred for 5-6 hours, washed and dried to obtain hydroxylated polyethylene; (2) Hydroxylated polyethylene and polyurethane prepolymer with a mass ratio of 1:2-3 are sequentially added to toluene, a catalyst is added, and stirred at 100-105°C for 1-2 hours, washed and dried to obtain polyethylene-polyurethane-polyethylene.

7. The low-smoke zero-halogen optical cable sheath material prepared by the preparation method of the low-smoke zero-halogen optical cable sheath material with easy peeling and high resilience according to claim 1.