阅读说明：本技术 一种具有高耐热性的mpp电缆护套管及其生产工艺 (MPP cable sheath pipe with high heat resistance and production process thereof ) 是由 孙捷 陈凌飞 金沁馨 于 2021-09-11 设计创作，主要内容包括：本发明涉及一种具有高耐热性的MPP电缆护套管及其生产工艺,包括绝缘层、缓冲层和阻燃高耐热层,绝缘层包覆在导体表面,缓冲层填充在绝缘层和阻燃高耐热层之间；将交联聚乙烯材料包覆在导体表面形成绝缘层,之后在绝缘层表面均匀缠绕玻璃纤维,形成缓冲层,最后通过挤包工艺将阻燃高耐热层包覆在缓冲层表面,制得MPP电缆护套管；设置玻璃纤维作为缓冲层,能够提高护套管的抗冲击性能,还制备出阻燃高耐热层,具有优异的阻燃性能,当与填充料共混入基体中时,在填充料的催化作用下加快发挥阻燃功效,赋予该电缆护套管优异的阻燃性能。(The invention relates to an MPP cable sheath pipe with high heat resistance and a production process thereof, wherein the MPP cable sheath pipe comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein the insulating layer is coated on the surface of a conductor, and the buffer layer is filled between the insulating layer and the flame-retardant high heat-resistant layer; coating a crosslinked polyethylene material on the surface of a conductor to form an insulating layer, uniformly winding glass fibers on the surface of the insulating layer to form a buffer layer, and finally coating a flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to obtain the MPP cable sheath pipe; the glass fiber is arranged as the buffer layer, so that the impact resistance of the protective sleeve can be improved, the flame-retardant high-heat-resistance layer is prepared, the flame-retardant high-heat-resistance layer has excellent flame-retardant performance, and when the flame-retardant high-heat-resistance layer is mixed with the filler into the matrix, the flame-retardant effect is accelerated under the catalytic action of the filler, so that the cable protective sleeve is endowed with excellent flame-retardant performance.)

1. The utility model provides a MPP cable sheath pipe with high heat resistance, includes insulating layer, buffer layer and fire-retardant high heat-resistant layer, and the insulating layer cladding is on the conductor surface, and the buffer layer is filled between insulating layer and fire-retardant high heat-resistant layer, its characterized in that: the flame-retardant high heat-resistant layer is prepared by the following steps:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 40-45 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to obtain the filler.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing, performing suction filtration and drying, then adding the reaction product into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, performing suction filtration and drying to obtain a synergistic material;

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material into a charging barrel, uniformly stirring for 5min at the rotating speed of 150 plus materials of 200r/min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 150 plus materials of 100 plus materials of 150r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 120: 1-3: 2-3: 1-1.5: 1.5-3.5: 5-10.

2. The MPP cable sheath with high heat resistance of claim 1, wherein: the insulating layer is made of cross-linked polyethylene material.

3. The MPP cable sheath with high heat resistance of claim 1, wherein: the buffer layer is made of glass fiber.

4. The MPP cable sheath with high heat resistance of claim 1, wherein: in the step S1, the dosage ratio of the salicylaldehyde to the potassium hydroxide aqueous solution is controlled to be 3 g: 50mL, the dosage of the hydrogen peroxide aqueous solution is 10-15% of the weight of the salicylaldehyde, in the step S2, the dosage ratio of the intermediate 1, the methanol and the methanol solution of the cobalt acetate is controlled to be 5 g: 20 mL: 30mL, in the step S3, the dosage ratio of the cyanuric chloride to the acetone is controlled to be 35.68-37.80 g: 250mL, the molar ratio of the cyanuric chloride to the KH550 is 1: 1, and the weight ratio of a reaction product to the dioxane is 5-5.8 g: 25 mL.

5. The MPP cable sheath with high heat resistance of claim 1, wherein: in step S3, the mixed solution a is prepared by mixing ethylenediamine and 10% by mass of aqueous sodium hydroxide solution in a weight ratio of 1: 10.

6. A process for manufacturing an MPP cable sheath with high heat resistance according to claims 1-5, wherein: the method comprises the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

Technical Field

The invention belongs to the technical field of cable materials, and particularly relates to an MPP cable sheath tube with high heat resistance and a production process thereof.

Background

The MPP pipe is also called MPP power cable protection pipe and is divided into an excavation type and a non-excavation type, the MPP non-excavation pipe is called MPP jacking pipe or a dragging pipe, the MPP pipe adopts modified polypropylene as main raw materials, the pipe has excellent electrical insulation, higher thermal deformation temperature and low-temperature impact performance, can be in butt joint by hot-melt welding, and is suitable for high-voltage transmission line cable arrangement pipes above 10 KV.

But the fire prevention thermal-insulated ability of current MPP power cable protection tube is relatively poor, when using in the actual process, life is short.

Disclosure of Invention

The invention aims to provide an MPP cable sheath pipe with high heat resistance and a production process thereof.

The purpose of the invention can be realized by the following technical scheme:

the utility model provides a MPP cable sheath pipe with high heat resistance, includes insulating layer, buffer layer and fire-retardant high heat-resistant layer, and the insulating layer cladding is on the conductor surface, and the buffer layer is filled between insulating layer and fire-retardant high heat-resistant layer, fire-retardant high heat-resistant layer includes that following step makes:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 40-45 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to obtain the filler.

In step S1, salicylaldehyde is dissolved in a potassium hydroxide aqueous solution, and then reacted under the oxidation action of hydrogen peroxide to generate an intermediate 1, which is a prepolymer, and then a methanol solution of cobalt acetate is blended to prepare a filler, wherein the filler is a complex of salicylaldehyde and metallic cobalt, and is added into a substrate, and when a system is combusted, the filler can exert a synergistic effect with a synergistic material, so that a catalytic system forms a stable carbon layer, thereby isolating oxygen and heat and improving the flame retardant effect.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding is finished and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing with a 50% acetone aqueous solution by volume fraction, washing again with deionized water, suction filtering, drying, then adding into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, suction filtering, and drying to obtain a synergistic material;

in the step S3, cyanuric chloride reacts with KH550 to generate an intermediate b, then reacts with ethylenediamine to generate an intermediate c, and finally, the intermediate c is polymerized to generate a synergist, wherein the reaction process is as follows:

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material into a charging barrel, uniformly stirring for 5min at the rotating speed of 150 plus materials of 200r/min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 150 plus materials of 100 plus materials of 150r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 120: 1-3: 2-3: 1-1.5: 1.5-3.5: 5-10.

Further: the insulating layer is made of cross-linked polyethylene material.

Further: the buffer layer is made of glass fiber.

Further: in the step S1, the dosage ratio of the salicylaldehyde to the potassium hydroxide aqueous solution is controlled to be 3 g: 50mL, the dosage of the hydrogen peroxide aqueous solution is 10-15% of the weight of the salicylaldehyde, in the step S2, the dosage ratio of the intermediate 1, the methanol and the methanol solution of the cobalt acetate is controlled to be 5 g: 20 mL: 30mL, in the step S3, the dosage ratio of the cyanuric chloride to the acetone is controlled to be 35.68-37.80 g: 250mL, the molar ratio of the cyanuric chloride to the KH550 is 1: 1, and the weight ratio of a reaction product to the dioxane is 5-5.8 g: 25 mL.

Further: in step S3, the mixed solution a is prepared by mixing ethylenediamine and 10% by mass of aqueous sodium hydroxide solution in a weight ratio of 1: 10.

A production process of an MPP cable sheath pipe with high heat resistance comprises the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

The invention has the beneficial effects that:

the MPP cable sheath pipe comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein glass fiber is arranged as the buffer layer, the impact resistance of the sheath pipe can be improved, the flame-retardant high heat-resistant layer is also prepared, in the preparation process, salicylaldehyde is dissolved in a potassium hydroxide aqueous solution, then, the salicylaldehyde reacts under the oxidation action of hydrogen peroxide to generate an intermediate 1 which is a prepolymer, then, a methanol solution of cobalt acetate is mixed to prepare a filler, the filler is a complex of the salicylaldehyde and metal cobalt, the complex is added into a matrix, when the system is combusted, the complex and a synergistic material can play a synergistic effect, a catalytic system forms a stable carbon layer, further, oxygen and heat are isolated, the flame-retardant effect is improved, the synergistic material is a compound containing a triazine structure from the structural viewpoint of structure, the flame-retardant high heat-resistant layer has excellent flame-retardant performance, when the synergistic material and the filler are mixed into the matrix, the flame retardant effect is accelerated under the catalysis of the filler, and the cable sheath tube has excellent flame retardant property.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

An MPP cable sheath pipe with high heat resistance comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein the insulating layer is coated on the surface of a conductor, and the buffer layer is filled between the insulating layer and the flame-retardant high heat-resistant layer;

the good cable sheath pipe is prepared by the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

The flame-retardant high heat-resistant layer is prepared by the following steps:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 40 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1, and in step S1, controlling the using amount ratio of the salicylaldehyde to the potassium hydroxide aqueous solution to be 3 g/50 mL, wherein the using amount of the hydrogen peroxide aqueous solution is 10% of the weight of the salicylaldehyde;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to prepare the filler, wherein the dosage ratio of the intermediate 1, the methanol and the methanol solution of cobalt acetate is controlled to be 5 g: 20 mL: 30 mL.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding is finished and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing with a 50% acetone aqueous solution by volume fraction, washing again with deionized water, suction filtering, drying, then adding into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, performing suction filtration and drying to obtain a synergistic material, controlling the dosage ratio of the cyanuric chloride to the acetone to be 35.68g to 250mL, the molar ratio of the cyanuric chloride to the KH550 to be 1 to 1, and controlling the weight ratio of a reaction product to dioxane to be 5g to 25 mL;

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant 1010, the epoxidized soybean oil, the filler and the synergistic material into a charging barrel, uniformly stirring at a rotating speed of 150r/min for 5min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 100r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 100: 1: 2: 1.5: 5.

Example 2

An MPP cable sheath pipe with high heat resistance comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein the insulating layer is coated on the surface of a conductor, and the buffer layer is filled between the insulating layer and the flame-retardant high heat-resistant layer;

the good cable sheath pipe is prepared by the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

The flame-retardant high heat-resistant layer is prepared by the following steps:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 42 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1, and in step S1, controlling the using amount ratio of the salicylaldehyde to the potassium hydroxide aqueous solution to be 3 g/50 mL, wherein the using amount of the hydrogen peroxide aqueous solution is 12% of the weight of the salicylaldehyde;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to prepare the filler, wherein the dosage ratio of the intermediate 1, the methanol and the methanol solution of cobalt acetate is controlled to be 5 g: 20 mL: 30 mL.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding is finished and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing with a 50% acetone aqueous solution by volume fraction, washing again with deionized water, suction filtering, drying, then adding into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, performing suction filtration and drying to obtain a synergistic material, controlling the dosage ratio of the cyanuric chloride to the acetone to be 35.80 g: 250mL, the molar ratio of the cyanuric chloride to the KH550 to be 1: 1, and controlling the weight ratio of a reaction product to dioxane to be 5.4 g: 25 mL;

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant 1010, the epoxidized soybean oil, the filler and the synergistic material into a charging barrel, uniformly stirring at a rotating speed of 150r/min for 5min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 100r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 110: 1.5: 2.5: 1.2: 2: 8.

Example 3

An MPP cable sheath pipe with high heat resistance comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein the insulating layer is coated on the surface of a conductor, and the buffer layer is filled between the insulating layer and the flame-retardant high heat-resistant layer;

the good cable sheath pipe is prepared by the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

The flame-retardant high heat-resistant layer is prepared by the following steps:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 45 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1, and in step S1, controlling the using amount ratio of the salicylaldehyde to the potassium hydroxide aqueous solution to be 3 g/50 mL, wherein the using amount of the hydrogen peroxide aqueous solution is 14% of the weight of the salicylaldehyde;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to prepare the filler, wherein the dosage ratio of the intermediate 1, the methanol and the methanol solution of cobalt acetate is controlled to be 5 g: 20 mL: 30 mL.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding is finished and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing with a 50% acetone aqueous solution by volume fraction, washing again with deionized water, suction filtering, drying, then adding into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, performing suction filtration and drying to obtain a synergistic material, controlling the dosage ratio of cyanuric chloride to acetone to be 37.50 g: 250mL, the molar ratio of cyanuric chloride to KH550 to be 1: 1, and controlling the weight ratio of a reaction product to dioxane to be 5.6 g: 25 mL;

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant 1010, the epoxidized soybean oil, the filler and the synergistic material into a charging barrel, uniformly stirring at a rotating speed of 200r/min for 5min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 150r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 118: 2.5: 1.4: 3: 8.

Example 4

An MPP cable sheath pipe with high heat resistance comprises an insulating layer, a buffer layer and a flame-retardant high heat-resistant layer, wherein the insulating layer is coated on the surface of a conductor, and the buffer layer is filled between the insulating layer and the flame-retardant high heat-resistant layer;

the good cable sheath pipe is prepared by the following steps:

and finally, coating the flame-retardant high-heat-resistance layer on the surface of the buffer layer by an extrusion coating process to prepare the MPP cable sheath pipe.

The flame-retardant high heat-resistant layer is prepared by the following steps:

step S1, adding salicylaldehyde into a potassium hydroxide aqueous solution with the mass fraction of 10%, stirring at a constant speed until the salicylaldehyde is dissolved, transferring the salicylaldehyde into a flask, heating in a water bath at 45 ℃, slowly adding a hydrogen peroxide aqueous solution with the mass fraction of 25%, heating to 75 ℃, continuing stirring at a constant speed and reacting for 10 hours to obtain an intermediate 1, and in step S1, controlling the using amount ratio of the salicylaldehyde to the potassium hydroxide aqueous solution to be 3 g/50 mL, wherein the using amount of the hydrogen peroxide aqueous solution is 15% of the weight of the salicylaldehyde;

and step S2, adding the intermediate 1 into methanol, stirring at a constant speed for 15min, then adding a methanol solution of cobalt acetate, heating to 70 ℃, stirring at a constant speed and reacting for 6h to generate a precipitate, filtering, and drying at 90 ℃ for 5h to prepare the filler, wherein the dosage ratio of the intermediate 1, the methanol and the methanol solution of cobalt acetate is controlled to be 5 g: 20 mL: 30 mL.

Step S3, adding cyanuric chloride into acetone, stirring at constant speed for 45min in an ice-water bath, adding KH550, dropwise adding a 10% sodium hydroxide aqueous solution by mass fraction to adjust the pH until the pH is 6, stirring at constant speed after dropwise adding is finished and reacting for 3h, then heating to 45 ℃, slowly dropwise adding a mixed solution a to adjust the pH until the pH is 8 to obtain a reaction product, washing with a 50% acetone aqueous solution by volume fraction, washing again with deionized water, suction filtering, drying, then adding into dioxane, heating to 100 ℃, stirring at constant speed to form a suspension, slowly dropwise adding the mixed solution a again to adjust the pH until the pH is 8, stirring and reacting for 5h, washing, performing suction filtration and drying to obtain a synergistic material, controlling the dosage ratio of cyanuric chloride to acetone to be 37.80 g: 250mL, the molar ratio of cyanuric chloride to KH550 to be 1: 1, and controlling the weight ratio of a reaction product to dioxane to be 5.8 g: 25 mL;

step S4, uniformly adding the MPP resin, the nano calcium carbonate powder, the antioxidant 1010, the epoxidized soybean oil, the filler and the synergistic material into a charging barrel, uniformly stirring at a rotating speed of 200r/min for 5min to obtain a mixture, adding the mixture into a double-screw extrusion granulator, wherein the extrusion rotating speed of the double-screw extrusion granulator is 150r/min to obtain a blank, performing melt extrusion and cooling to obtain the flame-retardant high heat-resistant layer, and controlling the weight ratio of the MPP resin, the nano calcium carbonate powder, the antioxidant, the plasticizer, the filler and the synergistic material to be 120: 3: 1.5: 3.5: 10.

Comparative example 1

In this comparative example, compared to example 1, IFA flame retardant was added in place of the filler and synergist of the present invention.

Comparative example 2

The comparative example is a flame-retardant MPP cable sheath pipe produced by a certain company on the market.

The flame retardant properties of examples 1 to 4 and comparative examples 1 to 2 were measured, and the results are shown in the following table:

it is seen from the table that examples 1-4 have excellent flame retardant properties.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is illustrative and explanatory only and is not intended to be exhaustive or to limit the invention to the precise embodiments described, and various modifications, additions, and substitutions may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the claims.