1. The high-strength flame-retardant PVC sheath pipe is characterized by comprising a reinforcing layer, a body and a flame-retardant layer, wherein the body is prepared from the following raw materials in parts by weight: 40-55% of polyvinyl chloride particles, 30-36% of graphene, 15-20% of light calcium carbonate, 6-8% of antioxidant, 4-6% of plasticizer and 2-3% of stabilizer. The preparation method comprises the following steps:

the method comprises the following steps: putting the raw materials which are proportioned and comprise antioxidant dibutyl hydroxy toluene, plasticizer dioctyl adipate, tricresyl phosphate and stabilizer zinc stearate into a crushing and stirring machine to be crushed to 50 meshes;

step two: putting the mixed materials into a stirring device, fully mixing by using the stirring device, and finally placing the product in a heating furnace to preheat to 200-300 ℃;

step three: and heating the smelting furnace to raise the temperature of the smelting pit to about 300-400 ℃, ensuring that all the body materials can be fully mixed and stirred, promoting the molecules among all the ingredients to be fully mixed, and opening the heating smelting furnace to cool the finished body mixed liquid for later use after fully melting the materials for 2-3 h.

2. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claim 1, wherein the preparation method comprises the following steps: the reinforcing layer comprises the following raw materials in parts by weight: 50-60% of phenolic resin, 30-36% of steel fiber and 10-20% of carbon fiber. The preparation method comprises the following steps:

the method comprises the following steps: putting the steel fibers and the carbon fibers into a crushing and stirring machine to be crushed to 40 meshes, taking out the crushed materials, putting the materials into a stirring device, and adding the phenolic resin to be fully mixed for more than 30 min;

step two: and in the process of stirring the materials, the materials are also required to be fully heated to 160 ℃, and the materials are kept and mixed for 1-1.5 h after being heated to 120 ℃.

3. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claim 1, wherein the preparation method comprises the following steps: the flame-retardant layer comprises the following raw materials in parts by weight: 40 to 50 percent of curing resin, 20 to 26 percent of glass beads, 10 to 16 percent of phosphate adhesive and 8 to 10 percent of butyl cellulose. The preparation method comprises the following steps:

the method comprises the following steps: accelerating the stirrer to 200-300r/min, uniformly stirring the cured resin and the glass beads to be mixed, heating an external container to about 130 ℃ in the stirring process, fully mixing for 30-40min, and keeping cooling for later use;

step two: adding phosphate adhesive and butyl cellulose with proper weight into the mixture to be used, fully mixing, and cooling the material to normal temperature.

4. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claims 1 to 3, wherein: the preparation method comprises the following steps:

the method comprises the following steps: keeping the temperature of the prepared raw materials of the body at about 120 ℃, putting the raw materials into a double-screw extruder, then adding the raw materials of the reinforcing layer, fully mixing, putting the mixture into the extruder, and extruding and granulating;

step two: after the extruded PVC protective sleeve is cooled and formed, uniformly coating a flame-retardant layer raw material uniformly stirred on the surface layer of the extruded PVC protective sleeve by using a brush, uniformly coating a layer of about 0.2mm, curing and irradiating by using an ultraviolet lamp, after curing is stable, uniformly coating a layer of about 0.4mm, and performing secondary curing;

step three: and cooling and packaging the cured PVC protective sleeve.

5. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claim 1, wherein the preparation method comprises the following steps: the ratio of dioctyl adipate to tricresyl phosphate in the plasticizer is 1: 1.

6. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claim 2, wherein the preparation method comprises the following steps: the length of the steel fibers and the carbon fibers is not more than 1 mm.

7. The high-strength flame-retardant PVC sheathing tube and the preparation method thereof according to claim 4, wherein the preparation method comprises the following steps: the rotating speed of the main machine of the double-screw extruder is 40 +/-5 rpm, and the material temperature is 150-160 ℃.

Background

Polyvinyl chloride is an initiator of vinyl chloride monomer (abbreviated as VCM) in peroxide, azo compounds and the like; or a polymer polymerized by a free radical polymerization mechanism under the action of light and heat. Vinyl chloride homopolymer and vinyl chloride copolymer are generally called vinyl chloride resin, the molecular weight of PVC produced industrially is generally within the range of 5-11 ten thousand, and the PVC has larger polydispersity, and the molecular weight is increased along with the reduction of polymerization temperature; without a fixed melting point, softening begins at 80-85 ℃, the temperature of 130 ℃ becomes a viscoelastic state, and the temperature of 160-180 ℃ begins to change into a viscous state; the composite material has good mechanical properties, the tensile strength is about 60MPa, and the impact strength is 5-10 kJ/m 2; has excellent dielectric properties.

However, the existing PVC protective sleeve does not have a good flame retardant effect when in use, and the strength of the PVC protective sleeve is not enough, so that the service life of the PVC protective sleeve cannot be prolonged, and the use effect of the PVC protective sleeve is improved.

Disclosure of Invention

The invention aims to provide a high-strength flame-retardant PVC (polyvinyl chloride) protective sleeve and a preparation method thereof, and aims to solve the problems that the conventional PVC protective sleeve does not have a good flame-retardant effect when in use, is not enough in strength, cannot prolong the service life and helps to increase the use effect of the PVC protective sleeve in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the high-strength flame-retardant PVC sheath pipe comprises a reinforcing layer, a body and a flame-retardant layer, wherein the body comprises the following raw materials in parts by weight: 40-55% of polyvinyl chloride particles, 30-36% of graphene, 15-20% of light calcium carbonate, 6-8% of antioxidant, 4-6% of plasticizer and 2-3% of stabilizer. The preparation method comprises the following steps:

the method comprises the following steps: putting the raw materials which are proportioned and comprise antioxidant dibutyl hydroxy toluene, plasticizer dioctyl adipate, tricresyl phosphate and stabilizer zinc stearate into a crushing and stirring machine to be crushed to 50 meshes;

step two: putting the mixed materials into a stirring device, fully mixing by using the stirring device, and finally placing the product in a heating furnace to preheat to 200-300 ℃;

step three: and heating the smelting furnace to raise the temperature of the smelting pit to about 300-400 ℃, ensuring that all the body materials can be fully mixed and stirred, promoting the molecules among all the ingredients to be fully mixed, and opening the heating smelting furnace to cool the finished body mixed liquid for later use after fully melting the materials for 2-3 h.

Further, the reinforcing layer comprises the following raw materials in parts by weight: 50-60% of phenolic resin, 30-36% of steel fiber and 10-20% of carbon fiber. The preparation method comprises the following steps:

the method comprises the following steps: putting the steel fibers and the carbon fibers into a crushing and stirring machine to be crushed to 40 meshes, taking out the crushed materials, putting the materials into a stirring device, and adding the phenolic resin to be fully mixed for more than 30 min;

step two: and in the process of stirring the materials, the materials are also required to be fully heated to 160 ℃, and the materials are kept and mixed for 1-1.5 h after being heated to 120 ℃.

Further, the flame-retardant layer comprises the following raw materials in parts by weight: 40 to 50 percent of curing resin, 20 to 26 percent of glass beads, 10 to 16 percent of phosphate adhesive and 8 to 10 percent of butyl cellulose. The preparation method comprises the following steps:

the method comprises the following steps: accelerating the stirrer to 200-300r/min, uniformly stirring the cured resin and the glass beads to be mixed, heating an external container to about 130 ℃ in the stirring process, fully mixing for 30-40min, and keeping cooling for later use;

step two: adding phosphate adhesive and butyl cellulose with proper weight into the mixture to be used, fully mixing, and cooling the material to normal temperature.

Further, the ratio of dioctyl adipate to tricresyl phosphate in the plasticizer is 1: 1.

Further, the length of the steel fibers and carbon fibers does not exceed 1 mm.

Further, the main machine rotating speed of the double-screw extruder is 40 +/-5 rpm, and the material temperature is 150-160 ℃.

Compared with the prior art, the invention has the beneficial effects that: the high-strength flame-retardant PVC sheath pipe and the preparation method thereof are characterized in that a reinforcing layer and a flame-retardant layer are added outside a pipe body, in the using process, two additional layer bodies can well improve the firm effect of the sheath pipe and are added with the proportion of the whole material, the improvement of the use strength and the toughness of the PVC sheath pipe is facilitated, the service life of the whole sheath pipe can be greatly prolonged, the arrangement of glass beads inside the flame-retardant layer is facilitated, the friction index of the flame-retardant layer is improved, the external friction effect of the flame-retardant layer is improved, the hardness index of the flame-retardant layer is further increased under the irradiation of an ultraviolet lamp, the smooth formation of crystallization of the sheath pipe is facilitated, other additives are mixed with each other, the toughness of the sheath pipe is also facilitated, and therefore, after the surface is subjected to heavy impact, the external structure can quickly and equally distribute force to each stress point, and the effect of reinforcing the whole pipe body is achieved, and grinding before most material refabrication, homogeneity when assurance body raw materials that can be better mix has led to its inside each part atress compact, and the flame retardant coating of its interpolation can improve the flame retardant efficiency of this pipeline, and help its normal cooling that can be better when using keeps stably.

Detailed Description

The present invention will be further described with reference to the following examples.

The first embodiment is as follows:

the invention discloses a high-strength flame-retardant PVC (polyvinyl chloride) protective sleeve and a preparation method thereof, wherein the preparation method comprises the following steps:

the method comprises the following steps: putting the proportioned body raw materials into a crushing stirrer to be crushed to 50 meshes, putting the mixed materials into a stirring device, fully mixing by using the stirring device, finally placing the product into a heating furnace to be preheated to 300 ℃ for 200-;

step two: meanwhile, putting the steel fibers and the carbon fibers into a crushing stirrer to be crushed to 40 meshes, taking out the crushed materials, putting the materials into a stirring device, adding the phenolic resin, fully mixing for more than 30min, fully heating the materials in the process of stirring the materials to 120-160 ℃, and staying and mixing for 1-1.5 h;

step three: taking out the raw materials of the flame-retardant layer for later use, accelerating the stirrer to 200-300r/min, uniformly stirring the cured resin and the glass beads to be mixed, heating an external container to about 130 ℃ in the stirring process, fully mixing for 30-40min, and keeping cooling for later use;

step four: adding a proper amount of phosphate adhesive and butyl cellulose into the mixture to be used, fully mixing, and cooling the material to normal temperature;

step five: keeping the temperature of the prepared raw materials of the body at about 120 ℃, putting the raw materials into a double-screw extruder, then adding the raw materials of the reinforcing layer, fully mixing, putting the mixture into the extruder, and extruding and granulating;

step six: after the extruded PVC sheathing tube is cooled and formed, uniformly stirring the flame-retardant layer raw material on the surface layer of the PVC sheathing tube by using a brush, uniformly coating a layer of about 0.2mm, curing and irradiating by using an ultraviolet lamp, waiting for the stable curing, uniformly coating a layer of about 0.4mm, performing secondary curing, and finally cooling and packaging the cured PVC sheathing tube.

Example two:

the invention discloses a high-strength flame-retardant PVC (polyvinyl chloride) protective sleeve and a preparation method thereof, wherein the preparation method comprises the following steps:

the method comprises the following steps: putting the proportioned body raw materials into a crushing stirrer to be crushed to 60 meshes, putting the mixed materials into a stirring device, fully mixing by using the stirring device, finally putting the product into a heating furnace to be preheated to 350 ℃ for 250-;

step two: meanwhile, putting the steel fibers and the carbon fibers into a crushing stirrer to be crushed to 50 meshes, taking out the crushed materials, putting the materials into a stirring device, adding the phenolic resin, fully mixing for more than 30min, fully heating the materials in the process of stirring the materials to 130-165 ℃, and staying and mixing for 1-1.5 h;

step three: taking out the raw materials of the flame-retardant layer for later use, accelerating the stirrer to 150-250r/min, uniformly stirring the cured resin and the glass beads to be mixed, heating an external container to about 120 ℃ in the stirring process, fully mixing for 30-40min, and keeping cooling for later use;

step four: adding a proper amount of phosphate adhesive and butyl cellulose into the mixture to be used, fully mixing, and cooling the material to normal temperature;

step five: keeping the temperature of the prepared raw materials of the body at about 130 ℃, putting the raw materials into a double-screw extruder, then adding the raw materials of the reinforcing layer, fully mixing, putting the mixture into the extruder, and extruding and granulating;

step six: after the extruded PVC sheathing tube is cooled and formed, uniformly stirring the flame-retardant layer raw material on the surface layer of the PVC sheathing tube by using a brush, uniformly coating a layer of about 0.2mm, curing and irradiating by using an ultraviolet lamp, waiting for the stable curing, uniformly coating a layer of about 0.4mm, performing secondary curing, and finally cooling and packaging the cured PVC sheathing tube.

Example three:

the invention discloses a high-strength flame-retardant PVC (polyvinyl chloride) protective sleeve and a preparation method thereof, wherein the preparation method comprises the following steps:

the method comprises the following steps: putting the proportioned body raw materials into a crushing stirrer to be crushed to 70 meshes, putting the mixed materials into a stirring device, fully mixing by using the stirring device, finally placing the product into a heating furnace to be preheated to 400 ℃ plus 300 ℃, heating for about 50min, heating the furnace to raise the temperature of the melting cellar to 400 ℃ plus 300 ℃ to ensure that all the body materials can be fully mixed and stirred, promoting the molecules among all ingredients to be fully mixed, and opening the heating furnace to cool the finished body mixed liquid for standby after fully melting the materials for 2-3 h;

step two: meanwhile, putting the steel fibers and the carbon fibers into a crushing stirrer to be crushed to 60 meshes, taking out the crushed materials, putting the materials into a stirring device, adding the phenolic resin, fully mixing for more than 30min, fully heating the materials in the process of stirring the materials to 140-170 ℃, and staying and mixing for 1-1.5 h;

step three: taking out the raw materials of the flame-retardant layer for later use, accelerating the stirrer to 100-200r/min, uniformly stirring the cured resin and the glass beads to be mixed, heating an external container to about 110 ℃ in the stirring process, fully mixing for 30-40min, and keeping cooling for later use;

step four: adding a proper amount of phosphate adhesive and butyl cellulose into the mixture to be used, fully mixing, and cooling the material to normal temperature;

step five: keeping the temperature of the prepared raw materials of the body at about 140 ℃, putting the raw materials into a double-screw extruder, then adding the raw materials of the reinforcing layer, fully mixing, putting the mixture into the extruder, and extruding and granulating;

step six: after the extruded PVC sheathing tube is cooled and formed, uniformly stirring the flame-retardant layer raw material on the surface layer of the PVC sheathing tube by using a brush, uniformly coating a layer of about 0.2mm, curing and irradiating by using an ultraviolet lamp, waiting for the stable curing, uniformly coating a layer of about 0.4mm, performing secondary curing, and finally cooling and packaging the cured PVC sheathing tube.

Compared with the traditional process mode, the high-strength flame-retardant PVC protective sleeve and the preparation method thereof provided by the invention have the advantages that multiple raw materials are fully ground and subdivided, so that the uniformity of the whole PVC protective sleeve during mixing can be better ensured, the external stress uniformity of the PVC protective sleeve during use is greatly improved, and the service life of the PVC protective sleeve is prolonged.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.