Halogen-free flame-retardant composite material for cable filling rope and preparation method thereof

Abstract

The application discloses a kind of cable filling rope with halogen-free flame-retardant composite material and preparation method thereof, belong to composite material technical field.The application is used to solve the technical problems of poor cell quality, poor mechanical properties and flame-retardant properties of filling rope material in the prior art.A kind of preparation method of cable filling rope with halogen-free flame-retardant composite material includes the following steps: low-density polyethylene, high-density polyethylene, hybrid flame-retardant resin and modified nucleating agent are uniformly mixed to obtain foaming filling rope material;Foaming filling rope material is melt extruded to obtain cable filling rope with halogen-free flame-retardant composite material.The hybrid flame-retardant resin is obtained by reaction of polycyclic epoxy group cyclotriphosphazene, vinyl chloride methyl methacrylate copolymer, mixed inorganic powder, etc.;The modified nucleating agent is obtained by intercalating talc powder with modified diamide nucleating agent.The foaming filling rope material prepared by the application has the characteristics of high cell quality, excellent mechanical properties and flame-retardant properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a halogen-free flame-retardant composite material for cable filling rope and a preparation method thereof. BACKGROUND

[0002] The rapid development of the information age intensifies the social demand for optical cable industry, and high-quality and low-cost optical cable structure becomes the focus of enterprise research. In order to make the cable core round and improve the appearance quality, filling rope is needed to fill the gap of the insulating core during cabling; the filling rope is soft and can be combined and matched at will with different specifications to meet the needs of different gap shapes and areas, and is convenient and widely used. With the development of technology, in order to achieve the purpose of improving efficiency and reducing cost, microcell technology is introduced in the production of filling rope, so that the filling rope has the performance of foamed polymer. The application of microcell technology in the production of optical cable filling rope has the advantages of high production speed and low material consumption; the foamed filling rope reduces the weight of the filling rope on the basis of meeting the mechanical properties, thereby reducing the material cost. However, the existing foamed filling rope has the problem of poor cell quality; in addition, the cable filling rope also needs to have high mechanical properties and flame-retardant properties, thereby prolonging the service life and avoiding extreme conditions under fire and other specific environments.

[0003] Patent application CN104167257A discloses a tensile filling rope for optical cable. The components of the above-mentioned filling rope include high-density polyethylene, low-density polyethylene and micron-sized ultra-fine calcium carbonate; by filling calcium carbonate, the mechanical properties of the cable filling rope are enhanced. However, the above-mentioned tensile filling rope for cable fails to improve its flame retardance; how to prepare a foamed filling rope material with high mechanical properties, good foaming quality and good flame-retardant properties is a technical problem to be solved urgently.

[0004] In view of the above technical defects, a solution is proposed. SUMMARY

[0005] The present application relates to the technical field of composite materials, in particular to a halogen-free flame-retardant composite material for cable filling rope and a preparation method thereof.

[0006] The technical problems to be solved by the present application are as follows:

[0007] A preparation method of a halogen-free flame-retardant composite material for cable filling rope, comprising the following steps:

[0008] S1, according to the weight parts, 50-60 parts of low-density polyethylene, 20-30 parts of high-density polyethylene, 10-20 parts of hybrid flame-retardant resin and 3-5 parts of modified nucleating agent are uniformly mixed to obtain a foamed filling rope material;

[0009] S2, the foaming filling rope material is added into the double screw extruder, and is melt-extruded at 220-230 DEG C; nitrogen is injected during the melt-extrusion process, the injection pressure of the nitrogen is 5-6.5 MPa, and then the nitrogen is released through pressure reduction, so that the halogen-free flame-retardant composite material for cable filling rope is prepared.

[0010] The halogen-free flame-retardant composite material for cable filling rope is prepared by using the physical foaming technology.

[0011] Further, in step S1, the preparation method of the hybrid flame-retardant resin comprises the following steps:

[0012] A1, 2, 3-epoxy-1-propanol and triethylamine are added into N,N-dimethylformamide to obtain a mixed solution; hexachlorocyclotriphosphazene is added into N,N-dimethylformamide to obtain a mixed solution B; the mixed solution B is added dropwise into the mixed solution A, and after the dropwise addition is completed, the reaction is continued at 25-35 DEG C for 35-45 h, and then a viscous product, polycycloepoxy cyclotriphosphazene, is prepared through post-processing.

[0013] The polycycloepoxy cyclotriphosphazene is synthesized by using N,N-dimethylformamide as a solvent, triethylamine as a catalyst, and hexachlorocyclotriphosphazene and 2, 3-epoxy-1-propanol as reactants, and the reaction formula is as follows:

[0014]

[0015] A2, diatomite, expanded perlite and fly ash floating bead are uniformly mixed and ground to obtain a mixed inorganic powder; the polycycloepoxy cyclotriphosphazene and the mixed inorganic powder are uniformly mixed to obtain a composite refractory material; the vinyl chloride-methacrylate copolymer is heated and melted, and then the solidification agent and the composite refractory material are uniformly mixed and solidified to prepare the hybrid flame-retardant resin.

[0016] Further, in step A1, the amount ratio of 2, 3-epoxy-1-propanol, triethylamine and N,N-dimethylformamide is 3-6 g:3-5 g:20-30 mL, the amount ratio of hexachlorocyclotriphosphazene and N,N-dimethylformamide is 5-7 g:30-40 mL, and the amount ratio of the mixed solution B and the mixed solution A is 35-47 mL:25-35 mL; the post-processing step is that the triethylamine hydrochloride solid is removed by filtration, and the N,N-dimethylformamide is removed by rotary evaporation to obtain a solid; the solid is washed and vacuum dried to constant weight to obtain the viscous product, polycycloepoxy cyclotriphosphazene.

[0017] Further, in step A2, the mass ratio of diatomite, expanded perlite and fly ash floating bead is 1:1:2-3, the mass ratio of epoxy-based cyclophosphine and mixed inorganic powder is 9-10:1; the temperature of heating and melting of vinyl chloride-methacrylate copolymer is 160-180℃; the curing agent is phthalic anhydride, and the mass ratio of vinyl chloride-methacrylate copolymer, curing agent and composite refractory material is 50:0.5-1:5-10.

[0018] Further, in step S1, the preparation method of the modified nucleating agent comprises the following steps:

[0019] B1, uniformly mix p-aminoacetanilide, 1-bromohexane and ethanol, then reflux at 80-85℃ for 2-3h, then stop heating, cool and evaporate all ethanol solvent at 45-50℃ to obtain a solid; wash the solid with diethyl ether, then vacuum dry at 75-80℃ until constant weight to obtain a modified diamide nucleating agent;

[0020] The p-aminoacetanilide and 1-bromohexane undergo quaternary ammonium reaction to synthesize a modified diamide nucleating agent, and the reaction formula is as follows:

[0021]

[0022] B2, grind the talc powder to obtain talc powder powder; then mix the talc powder powder and hydrochloric acid solution and heat at 70-80℃ for 1-2h to obtain a talc powder suspension; centrifuge and remove impurities from the talc powder suspension to obtain a suspension after impurity removal; then add the modified diamide nucleating agent, stir uniformly, and heat in a water bath at 70-80℃ for 1-2h to obtain a modified talc powder suspension; the modified talc powder suspension is subjected to post-process treatment to obtain a modified nucleating agent.

[0023] Further, in step B1, the amount of p-aminoacetanilide, 1-bromohexane and ethanol is 1.5-3g:3.61-7.22g:200mL; in step B2, the concentration of the hydrochloric acid solution is 0.02-0.05mol / L, and the amount of talc powder powder and hydrochloric acid solution is 5-10g:100mL; the centrifugal speed of the talc powder suspension is 1000-1200r / min; and the amount of the suspension after impurity removal and the modified diamide nucleating agent is 50-100mL:10-15g.

[0024] Further, in step B2, the post-process treatment specifically comprises: pouring the modified talc powder suspension into a separatory funnel, standing and layering, and removing the lower layer filtrate by filtration; then adding distilled water and repeating the standing three times, and during each standing, the volume ratio of the modified talc powder suspension and distilled water is 1:5-10; collecting the upper layer suspended foam solid; vacuum drying, grinding and sieving the suspended foam solid to obtain a white powder modified nucleating agent.

[0025] As another aspect of the present application, a cable filler rope is prepared by the method of preparing a halogen-free flame-retardant composite material for a cable filler rope.

[0026] The present application has the following advantages:

[0027] 1. The present application uses physical foaming technology to prepare a halogen-free flame-retardant composite material for a cable filler rope with low density, using low-density polyethylene, high-density polyethylene, hybrid flame-retardant resin, and modified nucleating agent as raw materials. The foamed filler rope material is heated and melted in an extruder, while nitrogen is injected at a certain pressure, and then the nitrogen is released by reducing the pressure, thereby generating uniform bubbles that are tightly combined with the inner layer, to prepare a halogen-free flame-retardant composite material for a cable filler rope. Due to the uniform distribution of extremely small pores in the above-mentioned composite material, energy can be absorbed to achieve the purpose of toughening.

[0028] 2. The vinyl chloride methyl acrylate copolymer is doped into the polyethylene material as a modified resin, which can further improve the thermal stability and mechanical properties of the polyethylene material. 2,3-epoxy-1-propanol reacts with hexachlorocyclotriphosphazene to obtain a polycycloepoxy cyclophosphazene. The polycycloepoxy cyclophosphazene is compounded with the vinyl chloride methyl acrylate copolymer as an organic material, thereby further improving the flame retardance of the doped modified resin. Adding mixed inorganic powder to the above-mentioned two organic materials can improve the compatibility of the mixed inorganic powder in the organic body. The above-mentioned mixed inorganic powder is composed of diatomite, expanded perlite, and fly ash floating beads. The expanded perlite has a honeycomb structure with thin pore walls and high porosity, and can be used as a super-lightweight and high-efficiency thermal insulation material. The fly ash floating beads are glassy hollow microbeads, and their main components are SiO2 and Al2O3. The fly ash floating beads are filled with nitrogen and silicon dioxide. The hybrid flame-retardant resin synthesized by high-temperature curing of the polycycloepoxy cyclophosphazene and the mixed inorganic powder has high flame-retardant performance, and still has high mechanical properties and mechanical properties when reducing the cost of the synthesized filler rope material.

[0029] 3. When preparing rope-filled foam materials, the structure and shape of the nucleating agent effectively promote bubble nucleation. Designing and selecting the shape and structure of the nucleating agent is crucial for producing lightweight polymer foam materials with high density, small pore diameter, and uniform pore distribution. Talc, as an α-nucleating agent, can induce heterogeneous nucleation in polypropylene, significantly improving its toughness and dielectric properties. However, it cannot change the dominant crystal form of the polypropylene matrix. Talc is also difficult to disperse in polypropylene and has low nucleation efficiency. N,N"-dicyclohexyl-2,6-naphthalenedicarbamide, as a β-nucleating agent, effectively induces the formation of the β-form with high nucleation efficiency. Combining the two forms a highly efficient nucleating agent. Modified diamide nucleating agents are synthesized by reacting p-aminoacetanilide with 1-bromohexane. Modified diamide nucleating agents can be used as quaternary ammonium salts to intercalate talc, resulting in modified nucleating agents. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The diatomite in Examples 1-3 of the present invention is from Lingshou County Linrun Mineral Products Co., Ltd., with a product number of 002-001, a model of 325-1250, a SiO2 content of ≥95%, and a specific surface area of ​​0.2 m 2 / g; the expanded perlite in Examples 1-3 of the present invention was purchased from Yongqing County Jie Runfa Insulation Material Factory with the item number 932204; the fly ash beads in Examples 1-3 of the present invention were purchased from Lingshou County Ruohong Mineral Products Co., Ltd. with the item number rh021 and the product mesh number 100 mesh; the vinyl chloride methacrylate copolymer in Examples 1-3 of the present invention was purchased from Hubei Yongkuo Technology Co., Ltd. with the CAS number 25038-72-6; the talc in Examples 4-6 of the present invention was purchased from Lingshou County Qiangdong Mineral Products Processing Plant with the item number qd-679; the low-density polyethylene in Examples 7-9 of the present invention was purchased from Yuyao Huirun Plastics Co., Ltd. with the item number 8001 and the brand LD608; the high-density polyethylene in Examples 7-9 of the present invention was purchased from Shanghai Yanxing Plastics Co., Ltd. with the item number 1508S and the brand 1508S.

[0032] Example 1

[0033] This embodiment provides a method for preparing a hybrid flame retardant resin for a halogen-free flame retardant composite material for cable filling ropes, comprising the following steps:

[0034] A1, 3g of 2,3-epoxy-1-propanol, 3g of triethylamine and 20mL of N,N- dimethylformamide were added into a flask, mixed to obtain a mixed solution A. 5g of hexachlorocyclotriphosphazene was added into 30mL of N,N-dimethylformamide, stirred to obtain a mixed solution B. 25mL of the mixed solution A was added dropwise into 35mL of the mixed solution B, and the total dropping time was controlled within 20min. After the dropping was completed, the reaction was continued at 25°C with stirring at 100r / min for 35h, then the triethylamine hydrochloride solid was removed by filtration, and then N,N-dimethylformamide was removed by rotary evaporation, the vacuum degree of rotary evaporation was -0.1MPa, and the temperature of rotary evaporation was 70°C, to obtain a solid product. The solid product was washed with deionized water and dried at 70°C to obtain a viscous product of polyepoxy cyclophosphazene.

[0035] A2, diatomite, expanded perlite and fly ash floating bead were mixed uniformly according to a mass ratio of 1:1:2, and then ground in a grinder to a particle size of 100 meshes to obtain a mixed inorganic powder; the polyepoxy cyclophosphazene and the mixed inorganic powder were mixed uniformly according to a mass ratio of 9:1 to obtain a composite refractory material. The vinyl chloride methacrylate copolymer was heated and melted at 160°C, and then mixed uniformly with the curing agent phthalic anhydride and the composite refractory material according to a mass ratio of 50:0.5:5, and then poured into a preheated mold body, and then cured in an oven at 155°C to obtain a hybrid flame-retardant resin.

[0036] Example 2

[0037] The present embodiment provides a preparation method of a hybrid flame-retardant resin for a halogen-free flame-retardant composite material for cable filling ropes, which comprises the following steps:

[0038] A1, 3g of 2,3-epoxy-1-propanol, 3g of triethylamine and 20mL of N,N- dimethylformamide were added into a flask, mixed to obtain a mixed solution A. 5g of hexachlorocyclotriphosphazene was added into 30mL of N,N-dimethylformamide, stirred to obtain a mixed solution B. 25mL of the mixed solution A was added dropwise into 35mL of the mixed solution B, and the total dropping time was controlled within 20min. After the dropping was completed, the reaction was continued at 25°C with stirring at 100r / min for 35h, then the triethylamine hydrochloride solid was removed by filtration, and then N,N-dimethylformamide was removed by rotary evaporation, the vacuum degree of rotary evaporation was -0.1MPa, and the temperature of rotary evaporation was 70°C, to obtain a solid product. The solid product was washed with deionized water and dried at 70°C to obtain a viscous product of polyepoxy cyclophosphazene.

[0039] A2, diatomite, expanded perlite and fly ash floating bead are mixed uniformly according to a mass ratio of 1:1:2, then added into a grinder for grinding for 30 min to obtain mixed inorganic powder; the polyepoxy cyclophosphazene and the mixed inorganic powder are mixed uniformly according to a mass ratio of 9:1 to obtain a composite refractory material. The vinyl chloride-methacrylate copolymer is heated and melted at 170°C, then mixed uniformly with the curing agent phthalic anhydride and the composite refractory material according to a mass ratio of 50:0.8:8, poured into a preheated mold body, and then cured in an oven at 158°C to obtain the hybrid flame-retardant resin.

[0040] Example 3

[0041] The present embodiment provides a preparation method of a hybrid flame-retardant resin for a halogen-free flame-retardant composite material for cable filler rope, comprising the following steps:

[0042] A1, 6g of 2,3-epoxy-1-propanol, 5g of triethylamine and 30mL of N,N-dimethylformamide are added into a flask and mixed to obtain a mixed solution A. 7g of hexachlorocyclotriphosphazene is added into 40mL of N,N-dimethylformamide and stirred uniformly to obtain a mixed solution B. Then, 35mL of the mixed solution A is added dropwise into 47mL of the mixed solution B, and the total dropping time is controlled within 30 min. After the dropping is completed, stirring is continued at 35°C and 200r / min for 45h, then triethylamine hydrochloride solid is removed by filtration, and N,N-dimethylformamide is removed by rotary evaporation, with a vacuum degree of -0.2MPa and a rotary evaporation temperature of 80°C, to obtain a solid product. The solid product is washed with deionized water and vacuum dried to obtain a viscous product, polyepoxy cyclophosphazene.

[0043] A2, diatomite, expanded perlite and fly ash floating bead are mixed uniformly according to a mass ratio of 1:1:2, then added into a grinder for grinding for 30 min to obtain mixed inorganic powder; the polyepoxy cyclophosphazene and the mixed inorganic powder are mixed uniformly according to a mass ratio of 9:1 to obtain a composite refractory material. The vinyl chloride-methacrylate copolymer is heated and melted at 170°C, then mixed uniformly with the curing agent phthalic anhydride and the composite refractory material according to a mass ratio of 50:0.8:8, poured into a preheated mold body, and then cured in an oven at 158°C to obtain the hybrid flame-retardant resin.

[0044] Example 4

[0045] The present embodiment provides a preparation method of a modified nucleating agent for a halogen-free flame-retardant composite material for cable filler rope, comprising the following steps:

[0046] B1, in a 250 mL round bottom flask equipped with a spherical condenser, 200 mL of ethanol, 1.5 g of p-aminoacetanilide and 3.61 g of 1-bromohexane were added, and then refluxed at 80°C for 2 h, and then the heating was stopped and cooled. All the ethanol solvent was evaporated at 45°C using a rotary evaporator to obtain a solid. The solid was washed with ether three times, and then dried to constant weight at 75°C under vacuum to obtain a modified diamide nucleating agent.

[0047] B2, talc powder was ground to 50 mesh to obtain talc powder; then 5 g of talc powder and 100 mL of 0.02 mol / L hydrochloric acid solution were weighed into a 250 mL beaker, and then the beaker was transferred to a water bath, heated at 70°C for 1 h to obtain a talc suspension. The talc suspension was centrifuged to remove impurities to obtain a purified suspension, and the centrifugal speed was 1000 r / min; then 10 g of modified diamide nucleating agent was added to 50 mL of purified suspension, stirred uniformly, and then heated and stirred at 70°C for 1 h to obtain a modified talc suspension.

[0048] B3, all the modified talc suspension was poured into a separatory funnel, and then the layers were separated after standing for 24 h, and the lower layer was removed by filtration, and then distilled water was added and repeatedly standing for 3 times, and the volume ratio of modified talc suspension to distilled water was 1:5; the upper layer of suspended foam solid was collected by filtration each time, and then vacuum dried and ground through a 100 mesh screen to obtain a white powder, which was a modified nucleating agent.

[0049] Example 5

[0050] The present embodiment provides a preparation method of a modified nucleating agent for a halogen-free flame-retardant composite material for cable filler rope, comprising the following steps:

[0051] B1, in a 250 mL round bottom flask equipped with a spherical condenser, 200 mL of ethanol, 1.5 g of p-aminoacetanilide and 3.61 g of 1-bromohexane were added, and then refluxed at 80°C for 2 h, and then the heating was stopped and cooled. All the ethanol solvent was evaporated at 45°C using a rotary evaporator to obtain a solid. The solid was washed with ether three times, and then dried to constant weight at 75°C under vacuum to obtain a modified diamide nucleating agent.

[0052] B2, talc powder is ground to 80 mesh to obtain talc powder; 58 g of the talc powder and 100 mL of 0.03 mol / L hydrochloric acid solution are weighed into a 250 mL beaker, and then the beaker is transferred to a water bath, heated at 75°C for 1.5 h to obtain a talc powder suspension. The talc powder suspension is centrifuged to remove impurities to obtain a suspension after impurity removal, and the centrifugal speed is 1100 r / min; then 12 g of the modified diamide nucleating agent is added to 80 mL of the suspension after impurity removal, stirred uniformly, and then heated and stirred at a water bath temperature of 77°C for 1.5 h to obtain a modified talc powder suspension.

[0053] B3, all the modified talc powder suspensions are poured into a separatory funnel, and then allowed to stand for 24 h, and then separated by layers, and the lower layer filtrate is removed by filtration; distilled water is added repeatedly for 3 times, and the volume ratio of the modified talc powder suspension to the distilled water is 1:8; the upper layer suspended foam solid is collected by filtration each time, and then vacuum dried and ground through a 120 mesh sieve to obtain a white powder, which is the modified nucleating agent.

[0054] Example 6

[0055] The present embodiment provides a preparation method of a modified nucleating agent for a halogen-free flame-retardant composite material for cable filler rope, comprising the following steps:

[0056] B1, 200 mL of ethanol, 3 g of p-aminoacetanilide and 7.22 g of 1-bromohexane are added into a 250 mL round-bottom flask equipped with a spherical condenser, and then refluxed at 85°C for 3 h, and then the heating is stopped and allowed to cool. All the ethanol solvent is evaporated at 50°C by using a rotary evaporator to obtain a solid. The solid is washed with ether three times, and then vacuum dried at 80°C to constant weight to obtain a modified diamide nucleating agent.

[0057] B2, talc powder is ground to 100 mesh to obtain talc powder; 10 g of the talc powder and 100 mL of 0.05 mol / L hydrochloric acid solution are weighed into a 250 mL beaker, and then the beaker is transferred to a water bath, heated at 80°C for 2 h to obtain a talc powder suspension. The talc powder suspension is centrifuged to remove impurities to obtain a suspension after impurity removal, and the centrifugal speed is 1200 r / min; then 15 g of the modified diamide nucleating agent is added to 100 mL of the suspension after impurity removal, stirred uniformly, and then heated and stirred at a water bath temperature of 80°C for 2 h to obtain a modified talc powder suspension.

[0058] B3, pour all the modified talcum powder suspensions into a separatory funnel, stand for 24h, then separate the layers, remove the lower layer filtrate by filtration; add distilled water repeatedly for 3 times, the volume ratio of the modified talcum powder suspension and the distilled water is 1:10; collect the upper layer suspended foam solid each time, then vacuum dry, grind through a 200 mesh sieve, and the obtained white powder is the modified nucleating agent.

[0059] Example 7

[0060] The embodiment provides a preparation method of a halogen-free flame-retardant composite material for cable filling ropes, and the method comprises the following steps:

[0061] S1, according to the weight part, 50 parts of low-density polyethylene, 30 parts of high-density polyethylene, 10 parts of the hybrid flame-retardant resin prepared in example 1 and 3 parts of the modified nucleating agent prepared in example 4 are uniformly mixed to obtain a foaming filling rope material.

[0062] S2, the foaming filling rope material is added into a double-screw extruder and is melt-extruded at 220 DEG C, nitrogen is injected into the melt-extrusion process, the injection pressure of the nitrogen is 5 MPa, and then the nitrogen is released through pressure reduction to obtain the halogen-free flame-retardant composite material for cable filling ropes.

[0063] Example 8

[0064] The embodiment provides a preparation method of a halogen-free flame-retardant composite material for cable filling ropes, and the method comprises the following steps:

[0065] S1, according to the weight part, 55 parts of low-density polyethylene, 25 parts of high-density polyethylene, 15 parts of the hybrid flame-retardant resin prepared in example 2 and 4 parts of the modified nucleating agent prepared in example 5 are uniformly mixed to obtain a foaming filling rope material.

[0066] S2, the foaming filling rope material is added into a double-screw extruder and is melt-extruded at 225 DEG C, nitrogen is injected into the melt-extrusion process, the injection pressure of the nitrogen is 6 MPa, and then the nitrogen is released through pressure reduction to obtain the halogen-free flame-retardant composite material for cable filling ropes.

[0067] Example 9

[0068] The embodiment provides a preparation method of a halogen-free flame-retardant composite material for cable filling ropes, and the method comprises the following steps:

[0069] S1, according to the weight part, 60 parts of low-density polyethylene, 20 parts of high-density polyethylene, 20 parts of the hybrid flame-retardant resin prepared in example 3 and 5 parts of the modified nucleating agent prepared in example 6 are uniformly mixed to obtain a foaming filling rope material.

[0070] S2, the foaming filling rope material is added into the twin-screw extruder, melted and extruded at 230℃, nitrogen is injected into the melted and extruded material during the process, the injection pressure of the nitrogen is 6.5MPa, and then the nitrogen is released through pressure reduction, thereby obtaining the halogen-free flame-retardant composite material for cable filling rope.

[0071] Comparative Example 1

[0072] The difference between the present comparative example and Example 9 is that, when preparing the hybrid flame-retardant resin, step A1 is cancelled, and 2,3-epoxy-1-propanol is used to replace the polyepoxy-based cyclotriphosphazene in the same mass.

[0073] Comparative Example 2

[0074] The difference between the present comparative example and Example 9 is that, when preparing the hybrid flame-retardant resin, the mixed inorganic powder is replaced by the same mass of diatomite, thereby obtaining the composite refractory material.

[0075] Comparative Example 3

[0076] The difference between the present comparative example and Example 9 is that, the modified diamide nucleating agent is replaced by the same mass of p-aminoacetanilide, thereby obtaining the modified nucleating agent.

[0077] Comparative Example 4

[0078] The difference between the present comparative example and Example 9 is that, the modified nucleating agent is replaced by the same mass of modified diamide nucleating agent.

[0079] Performance test:

[0080] 1. The modified nucleating agent prepared in Examples 4-6 and Comparative Example 3 is subjected to thermogravimetric analysis to test the weight loss rate at 200℃.

[0081] Table 1. Performance test data of samples

[0082] Item Group Example 4 Example 5 Example 6 Comparative Example 3 Weight loss rate (%) 6.2 5.5 6.1 14.5

[0083] Data analysis: the halogen-free flame-retardant composite material for cable filling rope prepared in Examples 4-6 all has high thermal stability, which is manifested in that the modified nucleating agent prepared in Examples 4-6 has low thermal stability at 200℃, and the weight loss rate is not more than 10%. However, in Comparative Example 3, the same mass of p-aminoacetanilide is used to replace the modified diamide nucleating agent; since the modified diamide nucleating agent can be used as an intercalating agent to intercalate the talc powder, the intercalated talc powder can further improve the thermal stability of the modified nucleating agent, so the modified nucleating agent prepared in Comparative Example 3 has poor thermal stability, which is manifested in that the weight loss rate value is large.

[0084] The halogen-free flame-retardant composite material for cable filling rope prepared in Examples 7-9 and Comparative Examples 1-4 is extruded into a long strip, and the long strip is cut into 100x13x3.2mm3 spline.

[0085] 2. A 2mm deep hole was made in the middle of the sample prepared in Example 7-9 and Comparative Example 1-4, then the sample was soaked in water for 3 hours, and then impact brittle fracture was performed and the bubble size and bubble density were counted.

[0086] N0= (n / A) 3 / 2 V f , V f = p0-p f ;

[0087] In the formula, n is the number of bubbles in the scanning electron microscope, A is the area of the scanning electron microscope picture, V f is the bubble volume expansion ratio, p0is the density of the foamed filling rope material before and after foaming.

[0088] 3. According to GB 1033-86 "Test method for density and relative density of plastics", the density of the sample prepared in Example 7-9 and Comparative Example 1-4 was tested, and the average value was obtained after three tests. The tensile strength value and elongation at break value of the sample prepared in Example 7-9 and Comparative Example 1-4 were determined.

[0089] 4. According to the standard of ASTM D2863-9, the sample prepared in Example 7-9 and Comparative Example 1-4 was tested by LOI on the horizontal / vertical combustion instrument of model 5801. The specific test results are shown in the following table:

[0090] Table 2. Test data of sample performance

[0091] Item Group Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Average density (cells / cm 3 ) 5.18 x 10 6 ]] 5.11 x 10 6 ]]> 5.06 x 10 6 ]] 5.18 x 10 6 ]]> 5.13 x 10 6 ]]> 5.30 x 10 6 ]]> 5.24 x 10 6 ]]> Average size (pm) 50.1 49.3 48.3 50.7 51.3 55.1 53.6 Tensile strength (MPa) 24.5 25.3 26.1 25.2 20.6 22.5 22.6 Elongation at break (%) 150 155 165 151 130 139 141 LOI (vol %) 25.4 26.3 27.8 15.3 20.1 27.5 27.8

[0092] Data analysis: by comparing and analyzing the data in the above table, the halogen-free flame-retardant composite material for cable filling rope prepared in Example 7-9 has excellent bubble quality, which is specifically manifested in that the average size of the prepared foamed material is reduced, and the average density of the bubble is high. However, in Comparative Example 3, the mixture of p-aminophenylacetamide and talc powder is used to replace the modified nucleating agent, so that the average density of the bubble formed by the prepared halogen-free flame-retardant composite material for cable filling rope is larger, and the average size is larger; accordingly, the tensile strength and breaking strength value of the prepared halogen-free flame-retardant composite material for cable filling rope is reduced. In Comparative Example 4, the same quality of modified diamide nucleating agent is used to replace the modified nucleating agent; compared with the modified nucleating agent blended with α nucleating agent and β nucleating agent, the average density of the bubble of the halogen-free flame-retardant composite material for cable filling rope using the modified diamide nucleating agent is larger than that of the composite material prepared in Example 7-9, and the average size is larger.

[0093] In the comparative example 1, when the hybrid flame-retardant resin is prepared, the 2,3-epoxy-1-propanol is used to replace the polycyclophosphazene with the same mass; the hexachlorocyclotriphosphazene is used as the reaction monomer, which can further improve the flame-retardant property of the prepared hybrid flame-retardant resin, and the flame-retardant property of the composite material prepared in the comparative example 1 is the worst, and the limiting oxygen index value is the smallest.

[0094] Compared with the single diatomite, the mixed inorganic powder formed by the diatomite, the expanded perlite and the fly ash floating bead can not only improve the mechanical property of the prepared composite material, but also enhance the flame-retardant property of the prepared composite material. In the comparative example 2, the tensile strength and the elongation at break of the prepared composite material are lower, and the limiting oxygen index value of the prepared composite material is also lower.

[0095] The above content is only an example and description of the structure of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as the modifications or supplements do not deviate from the structure of the present application or exceed the scope defined by the present claims, and should belong to the protection scope of the present application.

[0096] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details, and the present application is not limited to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present specification. The present specification selects and describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is only limited by the claims and their entire scope and equivalents.

Claims

1. A method for preparing a halogen-free flame-retardant composite material for cable filling rope, characterized in that: The following steps are involved: S1. Mix 50-60 parts of low-density polyethylene, 20-30 parts of high-density polyethylene, 10-20 parts of hybrid flame retardant resin and 3-5 parts of modified nucleating agent by weight to obtain a foamed filling rope material; S2. Add the foamed filling rope material into a twin-screw extruder and melt extrude it at 220-230° C.; inject nitrogen during the melt extrusion process at a pressure of 5-6.5 MPa, and then release the nitrogen by decompression to prepare a halogen-free flame-retardant composite material for cable filling rope; In step S1, the preparation method of the modified nucleating agent comprises the following steps: B1, p-aminoacetanilide, 1-bromohexane, and ethanol are mixed, and then refluxed at 80-85°C for 2-3 hours. After that, heating is stopped, the mixture is allowed to cool, and all the ethanol solvent is evaporated at 45-50°C to obtain a solid; the solid is washed with ether, and then vacuum-dried at 75-80°C to constant weight to obtain a modified diamide nucleating agent; B2, grinding talc to obtain talc powder; then mixing the talc powder with a hydrochloric acid solution, heating at 70-80° C. for 1-2 hours to obtain a talc suspension; centrifuging the talc suspension and removing impurities to obtain a purified suspension; then adding a modified diamide nucleating agent, stirring evenly, and heating in a water bath at 70-80° C. for 1-2 hours to obtain a modified talc suspension; the modified talc suspension is subjected to a post-processing process to prepare a modified nucleating agent; In step S1, the preparation method of the hybrid flame retardant resin comprises the following steps: A1, 2,3-epoxy-1-propanol, and triethylamine are added to N,N-dimethylformamide and mixed to obtain a mixed solution A; hexachlorocyclotriphosphazene is added to N,N-dimethylformamide and stirred to obtain a mixed solution B; mixed solution A is then added dropwise to the mixed solution B. After the addition is complete, the reaction is continued at 25-35°C for 35-45 hours, and after post-processing, a viscous product, polyepoxy cyclophosphazene, is prepared; A2, diatomaceous earth, expanded perlite and fly ash beads are mixed and ground to obtain a mixed inorganic powder; polyepoxy cyclophosphazene and the mixed inorganic powder are mixed to obtain a composite refractory material; vinyl chloride methacrylate copolymer is heated and melted, and then mixed with a curing agent and the composite refractory material and cured to prepare a hybrid flame retardant resin.

2. The method for preparing a halogen-free flame-retardant composite material for cable filling rope according to claim 1, characterized in that: In step A1, the amount ratio of 2,3-epoxy-1-propanol, triethylamine and N,N-dimethylformamide is 3-6 g:3-5 g:20-30 mL, the amount ratio of hexachlorocyclotriphosphazene and N,N-dimethylformamide is 5-7 g:30-40 mL, and the amount ratio of mixed solution B to mixed solution A is 35-47 mL:25-35 mL; the post-processing steps are: filtering to remove triethylamine hydrochloride solid, rotary evaporation to remove N,N-dimethylformamide to obtain a solid; washing the solid and vacuum drying to constant weight to obtain a viscous product polyepoxy cyclic phosphazene.

3. The method for preparing a halogen-free flame-retardant composite material for cable filling rope according to claim 2, characterized in that: In step A2, the mass ratio of diatomaceous earth, expanded perlite and fly ash beads is 1:1:2-3, the mass ratio of polyepoxy cyclophosphazene and mixed inorganic powder is 9-10:1; the temperature of heating and melting the vinyl chloride methacrylate copolymer is 160-180°C; the curing agent is phthalic anhydride, and the mass ratio of the vinyl chloride methacrylate copolymer, curing agent and composite refractory material is 50:0.5-1:5-10.

4. The method for preparing a halogen-free flame-retardant composite material for cable filling rope according to claim 1, characterized in that: In step B1, the amount ratio of p-aminoacetanilide, 1-bromohexane and ethanol is 1.5-3g:3.61-7.22g:200mL; in step B2, the concentration of the hydrochloric acid solution is 0.02-0.05mol / L, the amount ratio of talc powder and hydrochloric acid solution is 5-10g:100mL; the centrifugal speed of the talc suspension is 1000-1200r / min; the amount ratio of the suspension after impurity removal and the modified diamide nucleating agent is 50-100mL:10-15g.

5. The method for preparing a halogen-free flame-retardant composite material for cable filling rope according to claim 1, characterized in that: In step B2, the post-processing step is specifically as follows: the modified talc suspension is poured into a separatory funnel, allowed to stand, separated, and the lower filtrate is removed by filtration; distilled water is added and allowed to stand three times, and each time the volume ratio of the modified talc suspension to distilled water is 1:5-10; the upper suspended foam solid is collected; the suspended foam solid is vacuum dried, ground, and sieved to prepare a white powder modified nucleating agent.

6. A halogen-free flame-retardant composite material for cable filling rope, characterized in that: The material is prepared by the method for preparing a halogen-free flame-retardant composite material for cable filling rope according to any one of claims 1 to 5.

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