Flame-retardant master batch, preparation method thereof and automatic industrial main cable

Abstract

The invention belongs to the technical field of composite materials, and provides a flame-retardant master batch, a preparation method thereof and an automatic industrial main cable. The preparation method comprises the following steps: firstly, reacting phosphonitrilic chloride trimer with phenol and ethidene diamine to synthesize a phosphazene flame retardant with excellent flame retardant property, and modifying through KH-550 to improve the compatibility of the phosphazene flame retardant with a matrix; secondly, boric acid and triphenyl phosphate are compounded in a PHPS matrix, ceramic body powder (MgO, Al2O3 and ZnO) subjected to high-temperature calcination and interface modification of KH-560 are combined, and ceramic body powder with excellent high-temperature ceramic forming performance is prepared; and then melting and mixing the polyethylene matrix with the phosphazene flame retardant, the ceramic body powder and inorganic fillers (magnesium hydroxide and aluminum hydroxide), and assisting with auxiliaries such as a silane coupling agent and an antioxidant to prepare the flame-retardant master batch which is used for a main cable for automatic industry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite materials, and relates to a flame-retardant master batch, a preparation method thereof and an automatic industrial general cable. BACKGROUND

[0002] In modern industrial environments, bus cables are widely used in manufacturing, energy, transportation and construction fields for efficient communication between sensors, controllers and actuators. However, such cables are often exposed to complex industrial application scenarios, such as high temperature, chemical corrosion, electrical noise or mechanical wear and tear under extreme conditions. At the same time, fire hazards are a major safety threat in industrial scenarios, especially in closed or densely populated environments, once the cable becomes a source of fire or a medium for fire spread, which can cause serious property damage and casualties. Therefore, it is of great significance to develop an automatic industrial bus cable with excellent flame-retardant and fireproof performance. There are a large number of flammable substances in industrial environments, such as oil and gas, dust or organic solvents, and cables may become a starting point or a way of fire spread due to short circuit, overload or external heat source. Traditional cable sheath and insulation layer materials are mostly based on polymers, which are easy to burn at high temperatures and release a large amount of toxic gases. Therefore, the flame-retardant and fireproof performance of the cable is directly related to the safety of industrial equipment and the control of fire spread.

[0003] The flame-retardant and fireproof cable technology on the market at present mainly includes halogen-based flame retardants and inorganic flame retardants. Among them, halogen-based flame retardants inhibit the chain reaction of fire by releasing halogen radicals during combustion to achieve flame-retardant effect, but release a large amount of toxic and corrosive gases during combustion, which does not meet the environmental protection requirements of low smoke and halogen-free. Inorganic flame retardants (such as aluminum hydroxide, magnesium hydroxide) reduce the combustion temperature by releasing water vapor through endothermic decomposition, but require a high addition amount, resulting in a significant reduction in the mechanical properties of the material. Phosphazene flame retardants release phosphorus oxides during combustion due to their unique chemical structure, which can quickly promote the formation of a dense carbonized layer on the surface of the material, and the released gas has low toxicity and less smoke, meeting the environmental protection requirements of low smoke and halogen-free; ceramic body powder can form a stable ceramic protective layer under high temperature conditions, further enhancing the fire resistance and thermal barrier effect of the material. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a flame-retardant master batch, a preparation method thereof and an automatic industrial bus cable, first, a phosphazene flame retardant with high carbon formation capacity is prepared by reacting hexachlorocyclotriphosphazene with phenol and ethylenediamine, and the dispersibility and compatibility of the phosphazene flame retardant in the matrix are improved by modifying the phosphazene flame retardant with KH-550 silane coupling agent. Secondly, ceramic powder is prepared by using boric acid and triphenyl phosphate as precursors, combining the ceramic properties of the PHPS matrix, and combining calcined modified MgO, Al2O3 and ZnO, and the interface bonding between the ceramic powder and the matrix is improved and the high-temperature ceramic formation capacity of the ceramic powder is enhanced by removing the surface hydroxyl groups and modifying the KH-560 coupling agent. Then, the phosphazene flame retardant, ceramic powder, inorganic filler and additives are mixed and granulated with the polyethylene matrix to prepare the flame-retardant master batch and the automatic industrial bus cable, thereby meeting the needs of actual production.

[0005] To achieve this purpose, the present application adopts the following technical solutions: In a first aspect, the present application provides a preparation method of a flame-retardant master batch, the preparation method comprising: S1, dispersing triethylamine and phenol dispersion liquid in 2-methyltetrahydrofuran, adjusting the temperature to a first temperature and adding ethylenediamine to obtain a mixed solution A, adjusting the temperature to a second temperature, dispersing hexachlorocyclotriphosphazene in 2-methyltetrahydrofuran and adding the mixed solution A, adjusting the temperature to a third temperature for reflux reaction to obtain a mixed solution B, dispersing the premixed trimethylolpropane, ground melamine and OP-10 in 2-methyltetrahydrofuran and then adding to the mixed solution B, continuing the reaction, cooling to 40℃, adding methyl tert-butyl ether to precipitate the product and washing, vacuum drying, then immersing the product in a KH-550 solution with pH=5, ultrasonic treatment, drying and grinding to obtain a phosphazene flame retardant; S2, adding boric acid dispersion liquid and triethylamine to PHPS, adjusting the temperature to a fourth temperature for stirring, then adding a mixed solution of triphenyl phosphate and acetic acid, adjusting the temperature to a second temperature for reaction, placing 7g of MgO, Al2O3 and ZnO in a muffle furnace, calcining at 400℃, then mixing with a KH-560 solution, pressurizing and homogenizing for dispersion, then adding to PHPS, adjusting the temperature to a fifth temperature for reaction, after the reaction is completed, distilling under reduced pressure and drying, grinding the dried product and spraying hexamethyldisilazane to obtain ceramic powder; S3, pre-mixing the dried polyethylene, methylphenyl silicone resin, phosphazene flame retardant and ceramic powder, then adding inorganic fillers, silane coupling agent, antioxidant and calcium stearate, melt extruding and granulating to obtain a flame-retardant master batch.

[0006] Hexachlorocyclotriphosphazene is a highly symmetrical cyclic compound with six phosphorus atoms and three nitrogen atoms forming a six-membered ring structure. Each phosphorus atom is connected to one chlorine atom, while the phosphorus and nitrogen atoms are connected by covalent bonds. Due to the bonding characteristics between phosphorus and nitrogen atoms, the phosphorus atoms exhibit partial positive charge, while the strong electron-withdrawing effect of the chlorine atoms leads to a decrease in electron cloud density on the phosphorus atoms, resulting in a higher positive charge. This electronic property makes hexachlorocyclotriphosphazene exhibit extremely strong electrophilicity under certain reaction conditions, especially under the action of nucleophilic reagents, its phosphorus-chlorine bond is easily broken, and thus replaced by nucleophilic reagents. As a nucleophilic reagent, the hydroxyl oxygen atom in the phenol molecule has a certain nucleophilicity, but the hydroxyl group in phenol is weakly acidic, and it is difficult for it to effectively attack the phosphorus atom of hexachlorocyclotriphosphazene by its own nucleophilicity. Therefore, triethylamine is added as a basic reagent, which mainly functions to deprotonate the hydroxyl group of phenol to form phenolate, enhancing the nucleophilicity of the phenol molecule and making its oxygen atom have a higher negative charge density, thus more easily attacking the phosphorus atom of hexachlorocyclotriphosphazene. After the formation of phenolate, its oxygen atom attacks the phosphorus atom of hexachlorocyclotriphosphazene by nucleophilic attack, causing the phosphorus-chlorine bond to break, and the chlorine atom to be removed as a leaving group. The phenolate replaces one chlorine atom in the hexachlorocyclotriphosphazene molecule one by one, and finally forms a completely substituted phenoxyphosphazene derivative. After the substitution of phenol on hexachlorocyclotriphosphazene is completed, ethylenediamine is added to further cross-link the molecules. Ethylenediamine molecules contain two amino functional groups, each of which has strong nucleophilicity. The addition of ethylenediamine allows the molecules to form chemical bonds between the amino groups and the phosphorus atoms of phosphazene, further improving the cross-linking degree of phosphazene molecules. In this process, the lone pair electrons in the amino group attack the phosphorus atom in the phosphazene molecule by nucleophilic attack, causing some of the phenoxy groups in the phosphazene structure to be replaced by amino groups while forming new phosphorus-nitrogen bonds. Not only does this enhance the thermal stability of the phosphazene flame retardant, but it also introduces more nitrogen-containing structures, further improving its flame retardant performance.

[0007] After the crosslinking of ethylenediamine, trimethylolpropane and melamine were added to further modify the phosphazene derivatives. Trimethylolpropane is a trifunctional compound with three hydroxyl groups in its molecule, which can form hydrogen bonds with the hydroxyl or oxo groups in the phosphazene molecules or form ether bonds through condensation reactions under certain conditions. This modification is mainly to enhance the interaction between phosphazene molecules, thereby improving the thermal stability and mechanical strength of the flame retardant. The introduction of melamine provides additional nitrogen sources for the system, and the multiple nitrogen atoms in its molecule can release ammonia gas at high temperatures, which can dilute flammable gases and inhibit the spread of flames. At the same time, the structure of melamine contains a large number of nitrogen-hydrogen bonds, which can react with the active intermediates (such as phosphoric acid or phosphate) generated by phosphazene molecules during high-temperature degradation, further promoting the formation of carbonized layer. Finally, the product was surface modified by KH-550 solution. KH-550 is a silane coupling agent that contains both inorganic and organic functional groups in its molecule. The ethoxy functional group of KH-550 will form silanol groups after hydrolysis, which can undergo condensation reactions with the hydroxyl groups on the surface of phosphazene molecules, forming siloxane bonds on the surface of phosphazene molecules. This process not only enhances the surface activity of phosphazene flame retardants, but also improves their dispersibility in the polymer matrix. In addition, the aminopropyl functional group in the KH-550 molecule can react with the polar functional groups in the polymer matrix, thereby establishing a strong interfacial bond between the flame retardant and the matrix, effectively solving the problem of uneven dispersion of phosphazene flame retardants in the polymer matrix, and significantly improving the mechanical properties and flame retardant effect of the composite material.

[0008] Boric acid is a weak acid, which can partially dissociate into trihydroxy borate ions in solution. Dibutyl phthalate, as a high-boiling organic solvent, can not only effectively disperse boric acid, but also interact with organic components in the reaction system through its non-polar part, stabilizing the physical dispersion state in the system. Triethylamine, as an organic base, can adjust the pH value of the solution and promote the dissociation of boric acid. Subsequently, the boric acid dispersion is mixed with PHPS and stirred at a certain temperature. In this stage, boric acid reacts with PHPS to form a boron-oxygen-silicon-nitrogen network structure. PHPS is a polyhydrosilazane containing a large number of amino-silicon bonds and silicon-hydrogen bonds in its molecule. The silicon-hydrogen bond is easily broken and reacts with the hydroxyl group of boric acid to form a silicon-oxygen bond. At the same time, boric acid can form hydrogen bonds with the amino group in PHPS through its hydroxyl group, further enhancing the degree of chemical cross-linking in the system. The main purpose of this stage is to introduce boron-oxygen and silicon-oxygen bonds through the chemical reaction between boric acid and PHPS, thereby endowing the final ceramic body powder with the ability to form ceramics at high temperatures. After the above reaction is completed, triphenyl phosphate is added to the PHPS system and reacts with boric acid under the catalysis of acetic acid to form a network structure containing phosphorus-oxygen-boron bonds. Triphenyl phosphate is a phosphoric acid ester with strong reactivity. The phosphorus-oxygen double bond in its molecule has high electrophilicity and can undergo nucleophilic attack with the hydroxyl group in the boric acid molecule to form a phosphorus-oxygen-boron compound. The addition of triphenyl phosphate also introduces phosphorus elements, which can promote the formation of carbonized layers and inhibit the generation of flammable gases at high temperatures, thereby significantly improving the flame-retardant effect of the ceramic body powder.

[0009] Meanwhile, magnesium oxide, aluminum oxide, and zinc oxide were calcined in a muffle furnace for several hours to remove surface hydroxyl groups, which decomposed the adsorbed water and hydroxyl groups on the surface of the oxides at high temperatures to generate a more pure inorganic oxide surface. The calcined magnesium oxide, aluminum oxide, and zinc oxide were modified with a KH-560 solution, which is a silane coupling agent containing a silane group and an epoxy group in its molecule. The silane group can undergo condensation with the hydroxyl groups on the surface of the oxides to form a silicon-oxygen bond, thereby introducing an organic functional group on the surface of the oxides. This surface modification not only improves the dispersibility of the oxides in the organic matrix, but also enhances the compatibility with the matrix. The modified magnesium oxide, aluminum oxide, and zinc oxide were dispersed by pressure homogenization and then added to the PHPS system. The surface activity of the inorganic oxide particles was significantly improved by the KH-560, thereby enabling chemical reactions with the silicon-hydrogen bonds and amino groups in the PHPS molecules. The introduction of these particles further enhances the high-temperature performance and mechanical strength of the ceramic body powder. The surface of the ceramic body powder was treated with hexamethyldisilazane by spraying, which further improves the thermal and chemical stability of the ceramic body powder. Hexamethyldisilazane is a silicon-containing compound containing two silicon atoms and two nitrogen atoms in its molecule, which forms a dense silicon-oxygen-silicon or silicon-nitrogen-silicon network structure by reacting with the surface of the ceramic body powder. This surface treatment not only improves the high-temperature performance of the ceramic body powder, but also enhances its dispersibility and flowability in the polymer matrix.

[0010] As the core of the reaction, the unique molecular structure of hexachlorocyclotriphosphazene not only provides a high-activity reaction site, but also lays the foundation for the flame-retardant system through the thermal stability of the phosphorus-nitrogen skeleton. Phenol is introduced into the phosphazene molecule through a multi-step nucleophilic substitution reaction, further enhancing the high-temperature stability and carbonization ability of the molecule. The addition of ethylenediamine significantly improves the spatial network structure between molecules through cross-linking reaction, making it have higher anti-pyrolysis and anti-oxidation ability in material application. Phosphorus elements form polyphosphate compounds to form a stable carbonized layer at high temperatures; while nitrogen elements release ammonia gas to dilute combustible gases, and together with phosphorus compounds, further improve the density and heat insulation performance of the carbonized layer. The preparation of ceramic powder realizes the coupling of various chemical bonds and structure functions by introducing boric acid, triphenyl phosphate, inorganic oxides and PHPS. The condensation reaction between boric acid and PHPS forms a boron-oxygen-silicon network structure, which not only has extremely high thermal stability, but also provides a heat-resistant skeleton for the material through its chemical cross-linking properties. The addition of triphenyl phosphate further strengthens this network structure, which introduces phosphorus-oxygen-boron bonds through reaction with boric acid, thereby constructing a ceramic network with dynamic response capability. At high temperatures, the phosphorus-oxygen-boron network can quickly generate a stable ceramic layer, and at the same time, release phosphate compounds to promote the formation of a carbonized layer. Specifically, the phosphazene flame retardant generates a stable carbonized layer at high temperatures through its efficient phosphorus-nitrogen synergistic mechanism, while the ceramic powder further strengthens the physical strength and heat insulation performance of the carbonized layer through the boron-oxygen-silicon network and high-temperature ceramic behavior of inorganic oxides. This multi-level synergistic effect forms a flame-retardant system that combines gas-phase inhibition and solid-phase protection: nitrogen gas release in the gas phase can dilute combustible gases and reduce flame temperature, while the carbonized layer and ceramic layer in the solid phase synergistically work together to effectively isolate the transfer of oxygen and heat, enabling the material to exhibit excellent flame-retardant performance at high temperatures.

[0011] As a preferred technical solution of the present application, in S1, the volume ratio of triethylamine, phenol dispersion liquid and ethylenediamine is (22-26):100:(16-20), for example, it can be (22, 22.4, 22.8, 23.2, 23.6, 24.0, 24.4, 24.8, 25.2, 25.6 or 26.0):100:(16, 16.4, 16.8, 17.2, 17.6, 18.0, 18.4, 18.8, 19.2, 19.6 or 20.0), but is not limited to the listed values, other values not listed in this range are also applicable.

[0012] In some optional examples, the phenol dispersion liquid is 24g of phenol and 1g of polyethylene glycol 400 dispersed in 100mL of 2-methyltetrahydrofuran at 50℃.

[0013] In some alternative embodiments, the first temperature is 45-50 °C, for example, it can be 45 °C, 45.5 °C, 46 °C, 46.5 °C, 47 °C, 47.5 °C, 48 °C, 48.5 °C, 49 °C, 49.5 °C, or 50 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0014] In some alternative embodiments, the second temperature is 65-70 °C, for example, it can be 65 °C, 65.5 °C, 66 °C, 66.5 °C, 67 °C, 67.5 °C, 68 °C, 68.5 °C, 69 °C, 69.5 °C, or 70 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0015] In some alternative embodiments, the third temperature is 85-90 °C, for example, it can be 85 °C, 85.5 °C, 86 °C, 86.5 °C, 87 °C, 87.5 °C, 88 °C, 88.5 °C, 89 °C, 89.5 °C, or 90 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0016] In some alternative embodiments, the time of the reflux reaction is 6-7 h, for example, it can be 6 h, 6.1 h, 6.2 h, 6.3 h, 6.4 h, 6.5 h, 6.6 h, 6.7 h, 6.8 h, 6.9 h, or 7 h, but not limited to the listed values, other values not listed in the range are also applicable.

[0017] In some alternative embodiments, the time of the continued reaction is 3-4 h, for example, it can be 3 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h, 3.5 h, 3.6 h, 3.7 h, 3.8 h, 3.9 h, or 4 h, but not limited to the listed values, other values not listed in the range are also applicable.

[0018] In some alternative embodiments, the mass volume ratio of the hexachlorotriphosphazene, trimethylolpropane, ground melamine, and OP-10 is (27-30) g: (8-10) g: (15-17) g: (3-5) mL, such as (27, 27.3, 27.6, 27.9, 28.2, 28.5, 28.8, 29.1, 29.4, 29.7, or 30.0) g: (8, 8.2, 8.4, 8.6, 8.8, 9.0, 9.2, 9.4, 9.6, 9.8, or 10.0) g: (15, 15.2, 15.4, 15.6, 15.8, 16.0, 16.2, 16.4, 16.6, 16.8, or 17.0) g: (3, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4..8, or 5.0) mL, but is not limited to the listed values, as other, non-listed values within the range are equally applicable.

[0019] In some alternative embodiments, the mass volume ratio of the triethylamine and hexachlorotriphosphazene is (22-26) mL: (27-30) g, such as (22, 22.4, 22.8, 23.2, 23.6, 24.0, 24.4, 24.8, 25.2, 25.6, or 26.0) mL: (27, 27.3, 27.6, 27.9, 28.2, 28.5, 28.8, 29.1, 29.4, 29.7, or 30.0) g, but is not limited to the listed values, as other, non-listed values within the range are equally applicable.

[0020] In some alternative embodiments, the mass volume ratio of the triethylamine and hexachlorotriphosphazene is (22-26) mL: (27-30) g, such as (22, 22.4, 22.8, 23.2, 23.6, 24.0, 24.4, 24.8, 25.2, 25.6, or 26.0) mL: (27, 27.3, 27.6, 27.9, 28.2, 28.5, 28.8, 29.1, 29.4, 29.7, or 30.0) g, but is not limited to the listed values, as other, non-listed values within the range are equally applicable.

[0021] In some alternative embodiments, the mass volume ratio of the triethylamine and hexachlorotriphosphazene is (22-26) mL: (27-30) g, such as (22, 22.4, 22.8, 23.2, 23.6, 24.0, 24.4, 24.8, 25.2, 25.6, or 26.0) mL: (27, 27.3, 27.6, 27.9, 28.2, 28.5, 28.8, 29.1, 29.4, 29.7, or 30.0) g, but is not limited to the listed values, as other, non-listed values within the range are equally applicable.

[0022] In some alternative embodiments, the mass volume ratio of the triethylamine and hexachlorotriphosphazene is (22-26) mL: (27-30) g, such as (22, 22.4, 22.8, 23.2, 23.6, 24.0, 24.4, 24.8, 25.2, 25.6, or 26.0) mL: (27, 27.3, 27.6, 27.9, 28.2, 28.5, 28.8, 29.1, 29.4, 29.7, or 30.0) g, but is not limited to the listed values, as other, non-listed values within the range are equally applicable.

[0023] In some optional examples, the PHPS has a solids content of 20% and the solvent is xylene.

[0024] In some optional embodiments, the fourth temperature is 50-55 °C, such as 50 °C, 50.5 °C, 51 °C, 51.5 °C, 52 °C, 52.5 °C, 53 °C, 53.5 °C, 54 °C, 54.5 °C, or 55 °C, but is not limited to the recited values, as other, non-recited values within the range are equally applicable.

[0025] In some optional embodiments, the stirring time is 1-2 h, such as 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, or 2 h, but is not limited to the recited values, as other, non-recited values within the range are equally applicable.

[0026] In some optional examples, the phosphoric acid triphenyl ester mixture is 15 g of phosphoric acid triphenyl ester dispersed in 125 mL of o-xylene.

[0027] In some optional examples, the second temperature reaction time is 3-4 h, such as 3 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h, 3.5 h, 3.6 h, 3.7 h, 3.8 h, 3.9 h, or 4 h, but is not limited to the recited values, as other, non-recited values within the range are equally applicable. The calcination time is 2-3 h, such as 2 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, or 3 h, but is not limited to the recited values, as other, non-recited values within the range are equally applicable.

[0028] In some optional examples, the KH-560 solution has a mass fraction of 2 wt.%, the solvent is xylene / isopropyl alcohol at a volume ratio of 8:2, and 0.5 wt.% of acetic acid is added.

[0029] In some optional examples, the fifth temperature is 75-80 °C, such as 75 °C, 75.5 °C, 76 °C, 76.5 °C, 77 °C, 77.5 °C, 78 °C, 78.5 °C, 79 °C, 79.5 °C, or 80 °C, but is not limited to the recited values, as other, non-recited values within the range are equally applicable.

[0030] In some optional examples, the fifth temperature reaction time is 5-6 h, such as 5 h, 5.1 h, 5.2 h, 5.3 h, 5.4 h, 5.5 h, 5.6 h, 5.7 h, 5.8 h, 5.9 h, or 6 h, but is not limited to the recited values, as other, non-recited values within the range are equally applicable.

[0031] As a preferred technical solution of the present application, in S3, the mass ratio of polyethylene, methylphenyl silicone resin, phosphazene flame retardant, ceramic powder, inorganic filler, silane coupling agent, antioxidant and calcium stearate is 100:25:(15-25):(5-10):(5-10):(3-5):(1-2):(1-2), for example, it can be 100:(15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25):(5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0):(5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0):(3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8 or 5.0):(1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0):(1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0), but not limited to the listed values, other values not listed in the range are also applicable.

[0032] In some optional examples, the inorganic filler is magnesium hydroxide / aluminum hydroxide, with a mass ratio of 1:1.

[0033] In some optional examples, the silane coupling agent is KH-550.

[0034] In some optional examples, the antioxidant is 1010 / 168, with a mass ratio of 1:1.

[0035] In some optional examples, the melt extrusion conditions are: feed temperature 170°C, melt temperature 185°C, die temperature 175°C.

[0036] In a second aspect, the present application provides a flame-retardant master batch prepared by the preparation method of the first aspect.

[0037] In a third aspect, the present application provides an automatic industrial total cable, comprising a conductor core coated with an insulating layer and a shielding layer on the surface, and a flame-retardant layer coated outside, wherein the flame-retardant layer material is a flame-retardant master batch prepared by the preparation method of the first aspect.

[0038] Compared with the prior art, the application has the following beneficial effects: (1) in the phosphazene flame retardant, phosphorus elements generate polyphosphoric acid compounds during pyrolysis, forming a stable carbonized protective layer, and nitrogen elements release inert ammonia gas by decomposition, diluting combustible gases in the flame and reducing the flame temperature, and the synergistic effect not only improves the gas-phase flame-retardant effect of the material, but also enhances the solid-phase protection capability, and the synergistic effect of boric acid, triphenyl phosphate, PHPS and inorganic oxides further strengthens the solid-phase flame-retardant mechanism, the condensation reaction of boric acid and PHPS generates a boron-oxygen-silicon network structure, and the introduction of triphenyl phosphate forms a phosphorus-oxygen-boron bond through reaction with boric acid, showing high thermal stability and ceramic ability, and a dense ceramic protective layer can be formed on the surface of the material, improving the flame-retardant efficiency and high-temperature stability of the material; (2) the phosphazene flame retardant constructs a molecular skeleton containing phosphorus-nitrogen functional groups through the step-by-step substitution reaction of phenol on hexachlorocyclotriphosphazene, the aromatic ring structure of phenol endows the molecule with excellent thermal stability, the nitrogen element introduced through crosslinking reaction not only enhances the flame-retardant performance, but also increases the mechanical strength of the material through intermolecular interaction, the ceramic powder realizes the uniform distribution of inorganic particles in the organic matrix through surface modification and homogeneous dispersion, and the phosphorus-oxygen bond, silicon-oxygen bond, boron-oxygen bond and nitrogen-silicon bond jointly constitute a highly crosslinked and chemically stable network structure, and the mechanical strength and high-temperature stability of the material are improved through strong intermolecular forces. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 A flame-retardant master batch preparation method flow chart is provided for the embodiments 1-4 of the application. DETAILED DESCRIPTION

[0040] The technical solutions of the application will be described in detail below with reference to specific embodiments and drawings. The embodiments described herein are specific specific embodiments of the application, which are used to illustrate the concept of the application; these descriptions are all explanatory and exemplary, and should not be understood as limiting the embodiments of the application and the protection scope of the application. In addition to the embodiments described herein, those skilled in the art can also employ other technical solutions that are obvious based on the content disclosed in the claims and the description of the application, which include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0041] The chemical reagents used in the embodiments and comparative examples of the application are all commercially available goods, and are not subjected to any further purification treatment.

[0042] Embodiment 1 The embodiment provides a flame-retardant master batch and a preparation method thereof, and the preparation method specifically comprises the following steps: S1, 22 mL of triethylamine was dispersed in 100 mL of phenol dispersion liquid in 300 mL of 2-methyltetrahydrofuran, the temperature was adjusted to 41℃, and 16 mL of ethylenediamine was added to obtain a mixed solution A, the temperature was adjusted to 65℃, 27 g of hexachlorocyclotriphosphazene was dispersed in 100 mL of 2-methyltetrahydrofuran and added to the mixed solution A, the temperature was adjusted to 88℃, and the reaction was refluxed for 6.3 h to obtain a mixed solution B, 8.2 g of trimethylolpropane, 15.8 g of ground melamine and 3.5 mL of OP-10 were pre-mixed and then dispersed in 50 mL of 2-methyltetrahydrofuran and added to the mixed solution B, and the reaction was continued for 3.0 h, the temperature was lowered to 40℃, methyl tert-butyl ether was added to precipitate the product and wash, and the product was immersed in a 3.8 wt.% KH-550 solution with pH = 5, ultrasonic treated and dried and ground to obtain a phosphazene flame retardant; S2, 70 mL of boric acid dispersion liquid and 0.5 g of triethylamine were added to 200 g of PHPS with a solid content of 20%, the temperature was adjusted to 50℃ and stirred for 1.3 h, then 125 mL of triphenyl phosphate mixed solution and 0.5 mL of acetic acid were added, the triphenyl phosphate mixed solution was 15 g of triphenyl phosphate dispersed in 125 mL of o-xylene, the temperature was adjusted to 66℃ and the reaction was carried out for 3.5 h, 7 g of MgO, Al2O3 and ZnO were placed in a muffle furnace, calcined at 400℃ for 2.5 h, then mixed with a 2 wt% KH-560 solution, pressurized and homogenized, then added to the PHPS, the temperature was adjusted to 75℃ and the reaction was carried out for 5.2 h, after the reaction was completed, the product was distilled under reduced pressure and dried, the dried product was ground and sprayed with hexamethyldisilazane to obtain a ceramic powder; S3, 1000 g of polyethylene, 250 g of methylphenyl silicone resin, 150 g of phosphazene flame retardant and 50 g of ceramic powder were pre-mixed after drying, then 60 g of magnesium hydroxide / aluminum hydroxide, 32 g of KH-550, 12 g of antioxidant 1010 / 168 and 12 g of calcium stearate were added, and the mixture was melt extruded and granulated to obtain a flame retardant masterbatch, the melt extrusion conditions were as follows: feed temperature 170℃, melt temperature 185℃ and die temperature 175℃.

[0043] Example 2 The present embodiment provides a flame retardant masterbatch and a preparation method thereof, the preparation method specifically comprising the following steps: S1, 24 mL of triethylamine was dispersed in 100 mL of phenol dispersion liquid in 300 mL of 2-methyltetrahydrofuran, the temperature was adjusted to 40°C, and 18 mL of ethylenediamine was added to obtain a mixed solution A, the temperature was adjusted to 70°C, 28 g of hexachlorocyclotriphosphazene was dispersed in 100 mL of 2-methyltetrahydrofuran and added to the mixed solution A, the temperature was adjusted to 85°C and refluxed for 6.0 h to obtain a mixed solution B, 8.0 g of trimethylolpropane, 15.0 g of ground melamine and 3.0 mL of OP-10 were pre-mixed and then dispersed in 50 mL of 2-methyltetrahydrofuran and added to the mixed solution B, and the reaction was continued for 3.5 h, the temperature was lowered to 40°C, methyl tert-butyl ether was added to precipitate the product and washed, and the product was immersed in a 3.0 wt.% KH-550 solution with pH = 5, ultrasonically treated and dried and ground to obtain a phosphazene flame retardant; S2, 70 mL of boric acid dispersion liquid and 0.8 g of triethylamine were added to 200 g of PHPS with a solid content of 20%, the temperature was adjusted to 55°C and stirred for 1.0 h, then 125 mL of triphenyl phosphate mixed solution and 0.5 mL of acetic acid were added, the triphenyl phosphate mixed solution was 15 g of triphenyl phosphate dispersed in 125 mL of o-xylene, the temperature was adjusted to 65°C and reacted for 3.0 h, 7 g of MgO, Al2O3 and ZnO each were placed in a muffle furnace, calcined at 400°C for 2.0 h, then mixed with a 2 wt% KH-560 solution, pressurized and homogenously dispersed, and then added to the PHPS, the temperature was adjusted to 77°C and reacted for 5.0 h, after the reaction was completed, the product was distilled under reduced pressure and dried, the dried product was ground and sprayed with hexamethyldisilazane to obtain a ceramic body powder; S3, 1000 g of polyethylene, 250 g of methylphenyl silicone resin, 180 g of phosphazene flame retardant and 70 g of ceramic body powder were pre-mixed after drying, then 100 g of magnesium hydroxide / aluminum hydroxide, 30 g of KH-550, 16 g of antioxidant 1010 / 168 and 10 g of calcium stearate were added, and melt extrusion granulation was performed to obtain a flame retardant master batch, the melt extrusion conditions were as follows: feed temperature 170°C, melting temperature 185°C and die temperature 175°C.

[0044] Example 3 The present embodiment provides a flame retardant master batch and a preparation method thereof, and the preparation method specifically comprises the following steps: S1, 26 mL of triethylamine and 100 mL of phenol dispersion were dispersed in 300 mL of 2-methyltetrahydrofuran, the temperature was adjusted to 45°C, and 22 mL of ethylenediamine was added to obtain a mixed solution A, the temperature was adjusted to 68°C, 30 g of hexachlorocyclotriphosphazene was dispersed in 100 mL of 2-methyltetrahydrofuran and added to the mixed solution A, the temperature was adjusted to 90°C and refluxed for 7.0 h to obtain a mixed solution B, 10.0 g of trimethylolpropane, 16.4 g of ground melamine and 5.0 mL of OP-10 were pre-mixed and then dispersed in 50 mL of 2-methyltetrahydrofuran and added to the mixed solution B, and the reaction was continued for 4.0 h, the temperature was lowered to 40°C, methyl tert-butyl ether was added to precipitate the product, and the product was washed and dried under vacuum, then the product was immersed in a 5.0 wt.% KH-550 solution with pH = 5, ultrasonically treated and dried and ground to obtain a phosphazene flame retardant; S2, 70 mL of boric acid dispersion and 1.0 g of triethylamine were added to 200 g of PHPS with a solid content of 20%, the temperature was adjusted to 54°C and stirred for 2.0 h, then 125 mL of triphenyl phosphate mixture and 0.5 mL of acetic acid were added, the triphenyl phosphate mixture was 15 g of triphenyl phosphate dispersed in 125 mL of o-xylene, the temperature was adjusted to 70°C and reacted for 4.0 h, 7 g of MgO, Al2O3 and ZnO each were placed in a muffle furnace, calcined at 400°C for 2.7 h, then mixed with a 2 wt% KH-560 solution, pressurized and homogenously dispersed, and then added to the PHPS, the temperature was adjusted to 80°C and reacted for 6.0 h, after the reaction was completed, the product was distilled under reduced pressure and dried, the dried product was ground and sprayed with hexamethyldisilazane to obtain a ceramic body powder; S3, 1000 g of polyethylene, 250 g of methylphenyl silicone resin, 250 g of phosphazene flame retardant and 100 g of ceramic body powder were pre-mixed after drying, then 80 g of magnesium hydroxide / aluminum hydroxide, 45 g of KH-550, 10 g of antioxidant 1010 / 168 and 20 g of calcium stearate were added, and melt extrusion granulation was performed to obtain a flame retardant master batch, the melt extrusion conditions of the flame retardant master batch were as follows: feed temperature 170°C, melt temperature 185°C, and die temperature 175°C.

[0045] Example 4 The present embodiment provides a flame retardant master batch and a preparation method thereof, and the preparation method specifically comprises the following steps: S1, 23 mL of triethylamine and 100 mL of phenol dispersion were dispersed in 300 mL of 2-methyltetrahydrofuran, the temperature was adjusted to 43℃, and 20 mL of ethylenediamine was added to obtain a mixed solution A, the temperature was adjusted to 66℃, 29 g of hexachlorocyclotriphosphazene was dispersed in 100 mL of 2-methyltetrahydrofuran and added to the mixed solution A, the temperature was adjusted to 87℃, and the reaction was carried out under reflux for 6.8 h to obtain a mixed solution B, 9.4 g of trimethylolpropane, 17.0 g of ground melamine, and 4.6 mL of OP-10 were pre-mixed and then dispersed in 50 mL of 2-methyltetrahydrofuran and added to the mixed solution B, and the reaction was continued for 3.8 h, the temperature was lowered to 40℃, methyl tert-butyl ether was added to precipitate the product, and the product was washed and dried under vacuum, then the product was immersed in a 4.7 wt.% KH-550 solution with pH = 5, ultrasonic treatment was performed, and the product was dried and ground to obtain a phosphazene flame retardant; S2, 70 mL of boric acid dispersion and 0.7 g of triethylamine were added to 200 g of PHPS with a solid content of 20%, the temperature was adjusted to 53℃, and stirring was carried out for 1.7 h, then 125 mL of triphenyl phosphate mixed solution and 0.5 mL of acetic acid were added, the triphenyl phosphate mixed solution was 15 g of triphenyl phosphate dispersed in 125 mL of o-xylene, the temperature was adjusted to 68℃, and the reaction was carried out for 3.8 h, 7 g each of MgO, Al2O3, and ZnO were placed in a muffle furnace, calcination was carried out at 400℃ for 3.0 h, then a 2 wt% KH-560 solution was mixed, pressure homogenization dispersion was carried out, and then the product was added to the PHPS, the temperature was adjusted to 76℃, and the reaction was carried out for 5.7 h, after the reaction was completed, the product was distilled under reduced pressure and dried, the dried product was ground and sprayed with hexamethyldisilazane to obtain a ceramic body powder; S3, 1000 g of polyethylene, 250 g of methylphenyl silicone resin, 210 g of phosphazene flame retardant, and 80 g of ceramic body powder were pre-mixed after drying, then 70 g of magnesium hydroxide / aluminum hydroxide, 50 g of KH-550, 20 g of antioxidant 1010 / 168, and 17 g of calcium stearate were added, and melt extrusion granulation was carried out to obtain a flame retardant master batch, the melt extrusion conditions of the flame retardant master batch were as follows: feed temperature 170℃, melt temperature 185℃, and die temperature 175℃.

[0046] Comparative Example 1 This comparative example provides a flame retardant master batch and a preparation method thereof, which is different from Example 1 in that the mass of hexachlorocyclotriphosphazene in S1 is 40 g, which is 13 g more than that in Example 1, and other process parameters and operating conditions are completely the same as those in Example 1.

[0047] Comparative Example 2 This comparative example provides a flame retardant master batch and a preparation method thereof, which is different from Example 1 in that the mass of hexachlorocyclotriphosphazene in S1 is 14 g, which is 13 g less than that in Example 1, and other process parameters and operating conditions are completely the same as those in Example 1.

[0048] Comparative Example 3 The comparative example provides a flame-retardant master batch and a preparation method thereof, which is different from example 1 in that the mass of triphenyl phosphate in S2 is 25 g, which is increased by 10 g compared with example 1, and other process parameters and operating conditions are completely the same as those of example 1.

[0049] Comparative example 4 The comparative example provides a flame-retardant master batch and a preparation method thereof, which is different from example 1 in that the mass of triphenyl phosphate in S2 is 5 g, which is reduced by 10 g compared with example 1, and other process parameters and operating conditions are completely the same as those of example 1.

[0050] The limiting oxygen index test method is GB / T 2406.2-2009; the flame-retardant performance test method is GB / T 2408-2021. The test results are shown in Table 1.

[0051] Table 1 Test results of bus cables for automation industry of examples 1-4 and comparative examples 1-4 As can be seen from Table 1, compared with example 1, the limiting oxygen index of comparative example 1 increases, and the flame-retardant grade decreases; the limiting oxygen index and the flame-retardant grade of comparative example 2 both decrease. This is because the hexachlorotriphosphazene in comparative example 1 is excessive, the phosphazene provides more phosphorus elements, which can generate more polyphosphate at high temperature combustion, form a more dense carbonized layer, and enhance the nitrogen release capacity, improve the oxygen requirement to maintain combustion, but the excessive phosphazene content causes the carbonized layer to be too thick, which cracks or falls off during the combustion process, and the flame-retardant grade of the material decreases. The hexachlorotriphosphazene in comparative example 2 is insufficient, the amount of polyphosphate and nitrogen generated by the decomposition of phosphazene decreases, and the density and heat insulation of the carbonized layer are insufficient, so the flame-retardant grade decreases.

[0052] As can be seen from Table 1, compared with example 1, the limiting oxygen index of comparative example 3 increases, and the flame-retardant grade decreases; the limiting oxygen index and the flame-retardant grade of comparative example 4 both decrease. This is because the triphenyl phosphate in comparative example 3 is excessive, which can generate more phosphate to strengthen the oxygen-blocking effect of the carbonized layer, but excessive triphenyl phosphate will introduce too much low molecular weight product, which will volatilize during the combustion process, resulting in a decrease in the strength of the carbonized layer and cracks or falling off of the carbonized layer. The triphenyl phosphate in comparative example 4 is insufficient, and the generation of phosphate is insufficient, which greatly reduces the density and heat insulation of the ceramic layer, and at the same time, the carbonization capacity of the material is weakened, and the flame-retardant grade decreases.

[0053] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A process for the preparation of a flame retardant masterbatch, characterized in that, The preparation method comprises: S1, triethylamine and phenol dispersion liquid are dispersed in 2-methyltetrahydrofuran to obtain a mixed liquid A, hexachlorocyclotriphosphazene is added into the mixed liquid A to obtain a mixed liquid B, trimethylolpropane, ground melamine and OP-10 are added into the mixed liquid B to obtain a phosphazene flame retardant; S2, boric acid dispersion liquid and triethylamine are added into PHPS, and a phosphoric acid triphenyl ester mixed liquid and acetic acid are added, MgO, Al2O3 and ZnO are calcined in a muffle furnace and then added into the PHPS to obtain a ceramic body powder; S3, polyethylene, methylphenyl silicone resin, the phosphazene flame retardant and the ceramic body powder are premixed, inorganic fillers, silane coupling agent, antioxidant and calcium stearate are added, and melt extrusion is performed to obtain a flame-retardant masterbatch.

2. The method of claim 1, wherein the flame retardant masterbatch is prepared by mixing the flame retardant and the polymer in a ratio of 1 : 1 to 1 :

10. In S1, The volume ratio of the triethylamine, the phenol dispersion liquid and the ethylenediamine is (22-26): 100: (16-20).

3. The method for preparing flame-retardant masterbatch according to claim 1, characterized in that, In S1, The mass-volume ratio of the hexachlorocyclotriphosphazene, trimethylolpropane, ground melamine and OP-10 is (27-30) g: (8-10) g: (15-17) g: (3-5) mL. The mass-volume ratio of the triethylamine and the hexachlorocyclotriphosphazene is (22-26) mL: (27-30) g.

4. The method for preparing flame-retardant masterbatch according to claim 1, characterized in that, In S2, The volume-mass ratio of the boric acid dispersion liquid, triethylamine, PHPS, phosphoric acid triphenyl ester mixed liquid and acetic acid is 70 mL: (0.5-1) g: 200 g: 125 mL: (0.5-1) mL.

5. The method of claim 1, wherein the flame retardant masterbatch is prepared by mixing the flame retardant and the polymer in a ratio of 1: 10 to 10:

1. In S3, The mass ratio of the polyethylene, methylphenyl silicone resin, phosphazene flame retardant, ceramic body powder, inorganic fillers, silane coupling agent, antioxidant and calcium stearate is 100: 25: (15-25): (5-10): (5-10): (3-5): (1-2): (1-2).

6. The method of claim 1, wherein the flame retardant masterbatch is prepared by mixing the flame retardant and the polymer in a ratio of 1: 10 to 10:

1. In S3, The melt extrusion conditions are that the feeding temperature is 170 DEG C, the melt temperature is 185 DEG C, and the die temperature is 175 DEG C.

7. The flame-retardant masterbatch obtained by the preparation method according to any one of claims 1-6.

8. An automation industrial bus cable comprising a conductor core with a surface covering insulation layer and a shielding layer and a flame-retardant layer for covering externally, characterized in that The flame-retardant layer material is the flame-retardant masterbatch prepared by the preparation method according to claims 1-6 or is melt extruded from the flame-retardant masterbatch according to claim 7.

Images