Low-smoke halogen-free flame-retardant material for high-light-transmittance rubber-insulated optical cable and preparation method thereof

Abstract

The invention discloses a low-smoke halogen-free flame-retardant material for a high-light-transmittance rubber-insulated optical cable and a preparation method of the low-smoke halogen-free flame-retardant material. The flame-retardant material is prepared from the following raw materials in parts by weight: 30-45 parts of matrix resin, 10-20 parts of a compatilizer, 80-90 parts of a flame retardant, 2-4 parts of a lubricant, 0.1-0.3 part of an antioxidant and 2-5 parts of a smoke suppressant. The low-smoke halogen-free flame-retardant material is improved on the basis of a conventional low-smoke halogen-free flame-retardant material, so that the low-smoke halogen-free flame-retardant material has excellent mechanical property, cracking resistance and flame retardance, the smoke release amount during combustion is extremely low, the light transmittance can be greater than or equal to 85%, the production speed of 180 m / min or above is met, the extrusion surface is smooth, the wire diameter is stable, and the production and use requirements of rubber-covered wire optical cables can be met.

Description

Technical Field

[0001] The invention relates to the technical field of cable polymer materials, and in particular to a low-smoke halogen-free flame retardant material for a high-transmittance sheathed optical cable and a preparation method thereof. Background Art

[0002] With the full arrival of the 5G era, the development of the communications industry in my country has entered a new stage.

[0003] In this context, as an indispensable signal transmission tool in 5G networks, the performance and quality requirements of leather-line optical cables are also increasing. The outer sheath of leather-line optical cables usually adopts low-smoke halogen-free materials, which have the characteristics of low smoke and less harmful gas release when burning, and meet the high standards of fire safety in modern buildings. However, although traditional low-smoke halogen-free materials have good flame retardant properties, they still need to be improved in suppressing smoke and improving light transmittance. Therefore, the development of a low-smoke halogen-free flame retardant material for high-transmittance leather-line optical cables that has excellent flame retardant properties, can significantly reduce the amount of smoke released during combustion, and improve the light transmittance has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, a low-smoke, halogen-free flame retardant material for high-transmittance sheathed optical cable and a preparation method thereof are provided by optimizing the material formula and the preparation process. By compounding the flame retardant with the smoke suppressant, low smoke release and high transmittance can be achieved when the sheathed optical cable burns.

[0005] The present invention adopts the following technical solution:

[0006] A low-smoke, halogen-free flame retardant for a high-transmittance leather-wire optical cable is prepared from the following raw materials in parts by weight:

[0007] 30-45 parts of base resin

[0008] Compatibilizer 10-20 parts

[0009] Flame retardant 80-90 parts

[0010] 2-4 parts lubricant

[0011] Antioxidant 0.1-0.3 parts

[0012] 2-5 parts of smoke suppressant.

[0013] The matrix resin is a combination of two or three of ethylene-vinyl acetate copolymer, linear low-density polyethylene, and low-density polyethylene.

[0014] Preferably, the matrix resin is a composition of linear low-density polyethylene and ethylene-vinyl acetate copolymer, wherein the weight proportion of the linear low-density polyethylene is 10-20 parts, and the weight proportion of the ethylene-vinyl acetate copolymer is 20-25 parts.

[0015] More preferably, the linear low-density polyethylene has a melt index of 18-22 g / min at 190° C. and 2.16 kg.

[0016] More preferably, the ethylene-vinyl acetate copolymer has a melt index of 4-8 g / min at 190° C. and 2.16 kg, and the vinyl acetate content is 26-28 wt %.

[0017] Preferably, the compatibilizer is one or both of ethylene-vinyl acetate grafted maleic anhydride copolymer and polyethylene grafted maleic anhydride copolymer.

[0018] More preferably, the ethylene-vinyl acetate grafted maleic anhydride copolymer has a melt index of 4-8 g / min at 190° C. and 2.16 kg, and a maleic anhydride grafting rate of 3-8%.

[0019] More preferably, the polyethylene grafted maleic anhydride copolymer has a melt index of 2-6 g / min at 190° C. and 2.16 kg, and a maleic anhydride grafting rate of 5-9%.

[0020] Preferably, the flame retardant is one or both of aluminum hydroxide and magnesium hydroxide.

[0021] More preferably, the fineness of the aluminum hydroxide and magnesium hydroxide is 2500 mesh or above.

[0022] Preferably, the lubricant is calcium carbonate silica gel masterbatch.

[0023] More preferably, the calcium carbonate silica gel masterbatch is prepared by mixing calcium carbonate and methyl vinyl silicone rubber in a mass ratio of 7:3, the fineness of the calcium carbonate is 2500 mesh or above, the molecular weight of the methyl vinyl silicone rubber is 800,000-920,000, and the vinyl content is 21-24%.

[0024] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant AT-10 and antioxidant DLTP.

[0025] More preferably, the antioxidant 1010 and the antioxidant AT-10 are pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the antioxidant DLTP is dilauryl thiodipropionate.

[0026] Preferably, the smoke suppressant is an ammonium polyphosphate / magnesium aluminum hydrotalcite intercalation composite.

[0027] More preferably, the mass ratio of ammonium polyphosphate to magnesium-aluminum hydrotalcite in the ammonium polyphosphate / magnesium-aluminum hydrotalcite intercalation composite is (3-5):1, and the composite is prepared by grinding the two in a mortar for 30 minutes.

[0028] More preferably, the degree of polymerization of the ammonium polyphosphate is greater than 100, and the magnesium-aluminum hydrotalcite is nitrate magnesium-aluminum hydrotalcite.

[0029] A method for preparing a low-smoke, halogen-free barrier material for a high-transmittance covered optical cable comprises the following steps:

[0030] S1. Weigh various raw materials according to the formula, put them into the internal mixer for mixing, and obtain the mixed rubber material after reaching the set temperature and time;

[0031] S2. Extruding and granulating the mixed rubber material obtained in step S1 through a single screw extruder to obtain the low-smoke halogen-free barrier material for the high-transmittance sheathed optical cable.

[0032] The temperature set in step S1 is 165-175° C., and the time set is 13-16 minutes.

[0033] The extrusion temperature of the single screw extruder in step S2 is 100-120°C.

[0034] Preferably, the temperature of the single screw extruder is set to: 100-105°C in zone 1, 100-105°C in zone 2, 105-110°C in zone 3, 105-110°C in zone 4, 110-115°C in zone 5, 110-115°C in zone 6, 115-120°C in zone 7, and 115-120°C in zone 8.

[0035] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0036] A. Traditional flame retardants, such as aluminum hydroxide or magnesium hydroxide, have certain flame retardant effects, but their smoke suppression effect during combustion is limited. In order to further improve the light transmittance of the sheathed optical cable and reduce the amount of smoke released during combustion, the present invention introduces magnesium-aluminum hydrotalcite as a new type of smoke suppressant. The porous structure formed after thermal decomposition can absorb the smoke generated during combustion and effectively reduce the release of smoke. At the same time, magnesium-aluminum hydrotalcite also has the characteristic of interlayer anion exchangeability. By intercalating phosphate ions with flame retardant effects into magnesium-aluminum hydrotalcite, its flame retardant properties can be further improved.

[0037] B. The present invention improves on conventional low-smoke halogen-free flame retardant materials, making them have excellent mechanical properties, crack resistance and flame retardant properties, extremely low smoke release during combustion, light transmittance ≥ 85%, and can meet production speeds of more than 180m / min. The extruded surface is smooth and the wire diameter is stable, which can meet the production and use requirements of sheathed optical cables. DETAILED DESCRIPTION

[0038] The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0039] Embodiment 1:

[0040] This embodiment provides a low-smoke, halogen-free flame retardant for a high-transmittance covered optical cable, which is prepared from the following raw materials in parts by weight:

[0041]

[0042]

[0043] Among them, in the base resin, there are 25 parts of polyethylene-vinyl acetate copolymer, whose melt index is 5-7g / min and VA content is 26-28wt%; polyethylene is 10 parts, whose melt index is 18-22g / min. The compatibilizer is polyethylene grafted maleic anhydride copolymer, whose melt index is 3-4g / min and maleic anhydride grafting rate is 5%. The flame retardant is aluminum hydroxide with a fineness of 2500 mesh. The lubricant is calcium carbonate silica gel masterbatch. The antioxidant is a combination of antioxidant AT-10 and antioxidant DLTP, and the mass ratio of the two is 1:1. The smoke suppressant is an ammonium polyphosphate / magnesium aluminum hydrotalcite intercalation composite, and the mass ratio of ammonium polyphosphate and magnesium aluminum hydrotalcite is 3:1.

[0044] The preparation method comprises the following steps:

[0045] S1. The raw materials are put into an internal mixer according to a preset ratio for mixing at a mixing temperature of 172° C. for 15 min to obtain a uniformly mixed rubber material;

[0046] S2. The rubber material in step S1 is extruded and granulated by a single screw extruder to obtain the low-smoke, halogen-free flame retardant for high-transmittance leather-wire optical cable, wherein the particle length is 2-3 mm and the particle diameter is about 3 mm. The temperature of the single screw extruder is set as follows: zone 1 105°C, zone 2 105°C, zone 3 110°C, zone 4 110°C, zone 5 115°C, zone 6 115°C, zone 7 120°C, zone 8 120°C.

[0047] Embodiment 2:

[0048] This embodiment provides a low-smoke, halogen-free flame retardant for a high-transmittance covered optical cable, which is prepared from the following raw materials in parts by weight:

[0049]

[0050] Among them, in the base resin, there are 20 parts of polyethylene-vinyl acetate copolymer, whose melt index is 4-8g / min and VA content is 26-28wt%; 10 parts of polyethylene, whose melt index is 18-22g / min. The compatibilizer is polyethylene grafted maleic anhydride copolymer, whose melt index is 3-4g / min and maleic anhydride grafting rate is 5%. The flame retardant is aluminum hydroxide with a fineness of 2500 mesh. The lubricant is calcium carbonate silica gel masterbatch. The antioxidant is a combination of antioxidant AT-10 and antioxidant DLTP, and the mass ratio of the two is 1:1. The smoke suppressant is an ammonium polyphosphate / magnesium aluminum hydrotalcite intercalation composite, and the mass ratio of ammonium polyphosphate and magnesium aluminum hydrotalcite is 4:1.

[0051] The preparation method comprises the following steps:

[0052] S1. The raw materials are put into an internal mixer according to a preset ratio for mixing at a mixing temperature of 175° C. for 16 min to obtain a uniformly mixed rubber material;

[0053] S2. The rubber material in step S1 is extruded and granulated by a single screw extruder to obtain the low-smoke halogen-free flame retardant for high-transmittance leather-wire optical cable, wherein the particle length is 2-3 mm and the particle diameter is about 3 mm. The temperature of the single screw extruder is set as follows: 105°C in zone 1, 105°C in zone 2, 110°C in zone 3, 110°C in zone 4, 115°C in zone 5, 115°C in zone 6, 120°C in zone 7 and 120°C in zone 8.

[0054] Embodiment 3:

[0055] This embodiment provides a low-smoke, halogen-free flame retardant for a high-transmittance covered optical cable, which is prepared from the following raw materials in parts by weight:

[0056]

[0057] Among them, in the base resin, there are 25 parts of polyethylene-vinyl acetate copolymer, whose melt index is 5-7g / min and VA content is 26-28wt%; 20 parts of polyethylene, whose melt index is 18-22g / min. The compatibilizer is polyethylene grafted maleic anhydride copolymer, whose melt index is 2-6g / min and maleic anhydride grafting rate is 9%. The flame retardant is a combination of aluminum hydroxide and magnesium hydroxide, and the fineness is 2500 mesh. Among them, there are 70 parts of aluminum hydroxide and 15 parts of magnesium hydroxide. The lubricant is calcium carbonate silica gel masterbatch. The antioxidant is a combination of antioxidant AT-10 and antioxidant DLTP, and the mass ratio of the two is 1:1. The smoke suppressant is an ammonium polyphosphate / magnesium aluminum hydrotalcite intercalation composite, and the mass ratio of ammonium polyphosphate and magnesium aluminum hydrotalcite is 5:1.

[0058] The preparation method comprises the following steps:

[0059] S1. The raw materials are put into an internal mixer according to a preset ratio for mixing at a mixing temperature of 172° C. for 15 min to obtain a uniformly mixed rubber material;

[0060] S2. The rubber material in step S1 is extruded and granulated by a single screw extruder to obtain the low-smoke, halogen-free flame retardant for high-transmittance leather-wire optical cable, wherein the particle length is 2-3 mm and the particle diameter is about 3 mm. The temperature of the single screw extruder is set to: 100°C for zone 1, 100°C for zone 2, 105°C for zone 3, 105°C for zone 4, 110°C for zone 5, 110°C for zone 6, 115°C for zone 7 and 115°C for zone 8.

[0061] The low-smoke, halogen-free flame retardant materials for high-transmittance covered optical cables prepared in Examples 1-3 were subjected to various performance tests. The specific data are shown in Table 1.

[0062] Table 1 Performance test results of the embodiment

[0063]

[0064]

[0065] As can be seen from Table 1, the low-smoke halogen-free flame retardant material for high-transmittance sheathed optical cable of the present invention has excellent mechanical properties, crack resistance and flame retardant properties, while the smoke release during combustion is extremely low, the transmittance can be ≥85%, and it can meet the production speed of more than 180m / min, the extrusion surface is smooth, the wire diameter is stable, and it can meet the production and use requirements of sheathed optical cable, making up for the deficiency of reducing the extrusion speed due to increasing the amount of flame retardant filling to improve the transmittance.

[0066] Anything not described in the present invention is applicable to the prior art.

[0067] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A low-smoke, halogen-free flame retardant for high-transmittance covered optical cable, characterized in that: It is prepared from the following raw materials in parts by weight: 30-45 parts of base resin Compatibilizer 10-20 parts Flame retardant 80-90 parts 2-4 parts lubricant Antioxidant 0.1-0.3 parts 2-5 parts of smoke suppressant.

2. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The matrix resin is a combination of two or three of ethylene-vinyl acetate copolymer, linear low-density polyethylene, and low-density polyethylene.

3. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The compatibilizer is one or both of ethylene-vinyl acetate grafted maleic anhydride copolymer and polyethylene grafted maleic anhydride copolymer.

4. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The flame retardant is one or both of aluminum hydroxide and magnesium hydroxide.

5. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The lubricant is calcium carbonate silica gel masterbatch.

6. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant AT-10 and antioxidant DLTP.

7. The low-smoke, halogen-free flame retardant material for high-transmittance covered optical cable according to claim 1, characterized in that: The smoke suppressant is an ammonium polyphosphate / magnesium aluminum hydrotalcite intercalation composite.

8. A method for preparing the low-smoke halogen-free flame retardant material for high-transmittance covered optical cable according to any one of claims 1 to 7, characterized in that: The steps include: S1. Weigh various raw materials according to the formula, put them into the internal mixer for mixing, and obtain the mixed rubber material after reaching the set temperature and time; S2. Extruding and granulating the mixed rubber material obtained in step S1 through a single screw extruder to obtain the low-smoke halogen-free barrier material for the high-transmittance sheathed optical cable.

9. The preparation method according to claim 8, characterized in that: The temperature set in step S1 is 165-175° C., and the time set is 13-16 minutes.

10. The preparation method according to claim 8, characterized in that: The extrusion temperature of the single screw extruder in step S2 is 100-120°C.

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