A new energy automobile battery package shell polyphenylene sulfide flame-retardant material and a preparation method thereof

Abstract

The application relates to the field of high polymer materials, and particularly discloses a polyphenylene sulfide flame-retardant material for a new energy automobile battery package shell and a preparation method thereof. The polyphenylene sulfide flame-retardant material for the new energy automobile battery package shell comprises the following raw materials in parts by weight: 50-70 parts of polyphenylene sulfide resin, 1-3 parts of a plasticizer, 2-6 parts of a toughening agent, 2-3 parts of a flame retardant, 0.1-1 part of an antioxidant and 30-50 parts of modified composite fibers; the modified composite fibers comprise polydopamine modified carbon fibers and silicon dioxide modified aramid fibers in a mass ratio of 1:0.8-1. The polyphenylene sulfide flame-retardant material has low brittleness, high toughness, good tensile resistance and impact resistance, and is resistant to thermal oxidation, so that the polyphenylene sulfide cannot be cracked due to thermal oxidation.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer materials, in particular to a polyphenylene sulfide flame-retardant material for a battery package shell of a new energy vehicle and a preparation method thereof. BACKGROUND

[0002] The core of a new energy vehicle is a three-electricity system, including electric driving, a battery and electric control, and a power battery is an important power source of the current electric vehicle. The battery package shell is mainly used for protecting the power battery from damage when subjected to external collision and extrusion. The battery shell, as a bearing body of the battery module, plays a key role in the safe operation and protection of the battery module.

[0003] In the power battery system, the battery shell accounts for 20-30% of the total weight of the system and is a main structural part. Therefore, under the premise of ensuring the functional safety of the battery system and the overall safety of the vehicle, the lightweight of the battery shell has become one of the main improvement targets of the battery system. Polyphenylene sulfide is a thermoplastic crystalline polymer with excellent comprehensive performance, and has good forming processability, drug resistance, flame retardance, rigidity and modulus. It has high dimensional stability, excellent electrical performance, high fatigue resistance, good creep resistance, easy forming, and properties such as aging resistance, radiation resistance and non-toxicity. In addition, it has excellent heat resistance: the melting point is higher than 280℃, the heat distortion temperature is higher than 260℃, the long-term use temperature is 220-240℃, it degrades at 700℃ in air, it still has 40% mass in inert gas at 1000℃, the flame retardance can reach UL94 V-0 level, the oxygen index (LOI) is >57%, and it has good non-combustion performance. Therefore, it can be used as a lightweight flame-retardant material for the battery shell.

[0004] However, polyphenylene sulfide has a molecular structure in which benzene rings are alternately connected with sulfur atoms at the para position, and the molecular chain has great rigidity and regularity. Therefore, polyphenylene sulfide is a crystalline polymer, and the crystallinity can be as high as 70%-80%. Although polyphenylene sulfide has high rigidity, it is brittle and has poor toughness. In the prior art, polyphenylene sulfide is often blended with glass fibers to improve the mechanical properties of the blended material by using the high strength of the glass fibers. However, the affinity between the glass fibers and the resin matrix is poor, and the interfacial adhesion is low. Therefore, when the polyphenylene sulfide composite material is actually applied to the battery package shell, the problem of easy fragmentation still exists. SUMMARY

[0005] In order to reduce the brittleness of polyphenylene sulfide material, improve the toughness, and improve the protection of the battery module by the battery shell of the new energy vehicle, the application provides a polyphenylene sulfide flame-retardant material for a battery package shell of a new energy vehicle and a preparation method thereof.

[0006] In a first aspect, the application provides a polyphenylene sulfide flame-retardant material for a battery package shell of a new energy vehicle, which adopts the following technical scheme:

[0007] The polyphenylene sulfide flame-retardant material for a new energy automobile battery pack shell comprises the following raw materials in parts by weight: 50-70 parts of polyphenylene sulfide resin, 1-3 parts of plasticizer, 2-6 parts of toughening agent, 2-3 parts of flame retardant, 0.1-1 part of antioxidant, and 30-50 parts of modified composite fiber.

[0008] The modified composite fiber comprises polydopamine modified carbon fiber and silicon dioxide modified aramid fiber in a mass ratio of 1:0.8-1.

[0009] By adopting the above technical scheme, the toughening agent and the plasticizer are added in the blend material with polyphenylene sulfide resin as the matrix to improve the flexibility and impact resistance, and the polydopamine modified carbon fiber and the silicon dioxide modified aramid fiber are used as the composite fiber. The carbon fiber has very high mechanical strength and can be bent in multiple directions, has excellent bending resistance, and has excellent high-temperature resistance in an oxidizing atmosphere. The polydopamine has strong adhesion due to the similar composition structure to the mussel adhesive protein, thereby enhancing the roughness of the surface of the carbon fiber, improving the wettability of the polyphenylene sulfide to the surface of the carbon fiber, making the carbon fiber uniformly dispersed in the polyphenylene sulfide, and improving the mechanical strength and thermal oxidation resistance of the polyphenylene sulfide composite material. The aramid fiber is a linear polymer composed of aromatic groups and amide groups, and the main chain structure has high regularity. The macromolecules exist in a very stretched state. This structure makes the aramid fiber have the characteristics of ultrahigh strength, high modulus, and low elongation at break, so the mechanical properties are particularly outstanding. Moreover, the thermal oxidation resistance is also very excellent. Because the molecular chain contains a strong benzene ring bond structure, the aramid fiber can exist stably in a high-temperature environment. The surface of the aramid fiber is loaded with silicon dioxide to increase the roughness of the surface of the aramid fiber, increase the wettability of the polyphenylene sulfide to the aramid fiber, and enhance the dispersibility of the aramid fiber, thereby improving the bending resistance and impact resistance of the polyphenylene sulfide, enhancing the toughness of the battery pack shell, and improving the tensile resistance and impact resistance.

[0010] Optionally, the method for preparing the silicon dioxide modified aramid fiber is as follows:

[0011] The silane coupling agent KH550, ethanol, and deionized water are mixed, the pH is adjusted to 5-5.5, nano silicon dioxide is added, and the modification is carried out at 30-40℃ for 1-2h. The modified nano silicon dioxide is obtained by vacuum drying.

[0012] The polyvinylidene fluoride is dissolved to form a base solution with a concentration of 10wt%, the modified nano silicon dioxide is added to the base solution, and the mixture is uniformly sprayed on the aramid fiber and vacuum dried at 70-80℃. The mass ratio of the aramid fiber, the modified nano silicon dioxide, and the polyvinylidene fluoride is 10:1-1.5:0.1-0.15.

[0013] The sulfur atoms in the polyphenylene sulfide are not saturated, and the benzene rings and the sulfur atoms in the molecular chain form a conjugated structure, so that the sulfide bond in the polyphenylene sulfide macromolecule is easily oxidized into a sulfoxide group and a sulfone group, the benzene ring and the adjacent macromolecule are crosslinked due to the oxidation to form an oxygen bridge, and even the main chain is broken. The oxidation and breaking mode of the polyphenylene sulfide is mainly thermal oxidation and photooxidation. When used for the battery pack shell, the battery module generates heat during the driving of the automobile, and the heat causes thermal oxidation of the battery pack shell, so that the battery pack shell is prone to molecular chain rupture, poor toughness, and brittle fracture. Through the above technical scheme, the silica is modified by using the silane coupling agent KH550. The silane coupling agent KH550 will undergo a hydrolysis reaction when it comes into contact with water, and a silicon alcohol group is generated. In addition, part of the hydroxyl group will undergo a dehydration condensation reaction by itself to form an oligomeric siloxane containing a silicon hydroxyl group. The silicon hydroxyl group on the oligomeric siloxane forms a hydrogen bond with the hydroxyl group on the surface of the nanosilica, and the two are combined to form a hydrophobic film on the surface of the nanosilica. The C-F in the polyvinylidene fluoride molecular chain has strong bond energy, so that it has high stability on the surface when it is in an oxidizing environment. In addition, the polyvinylidene fluoride has high crystallinity, which can reduce the penetration probability of oxygen and has good thermal oxidation resistance. After the polyvinylidene fluoride is dissolved, a base liquid with a certain viscosity is obtained. Then the modified nanosilica is adhered to the aramid fiber by using the base liquid. The polar amino group at the other end of the silane coupling agent KH550 molecular chain combined with the nanosilica can interact with the polar F atom in the polyvinylidene fluoride to form a structure similar to a molecular bridge, coupling the nanosilica and the polyvinylidene fluoride. After vacuum drying, the hydrogen bond between the nanosilica and the oligomeric siloxane is broken and water is separated. Covalent bonds are formed between the two, which are tightly combined. In addition, the surface of the nanosilica changes from hydrophilic to oleophilic, slowing down the agglomeration of the nanosilica and effectively improving the dispersity of the nanosilica in the polyvinylidene fluoride base liquid. Therefore, the distribution of the modified nanosilica particles sprayed on the surface of the aramid fiber is more uniform. The modified nanosilica is uniformly adhered to the aramid fiber under the adhesion of the polyvinylidene fluoride, increasing the surface roughness of the aramid fiber and improving the bonding area between the aramid fiber and the polyphenylene sulfide resin, so that the two are more easily combined. In addition, the modified nanosilica can act as a heterogeneous nucleating agent in the polyphenylene sulfide resin, increasing the crystallinity of the polyphenylene sulfide resin and having a plasticizing effect on the polyphenylene sulfide resin, thereby improving the bending strength and impact strength of the composite material. Moreover, the modified nanosilica can effectively hinder the thermal oxidation crosslinking of the polyphenylene sulfide and reduce the thermal degradation reaction. The aramid fiber has strong heat resistance and oxidation resistance, and together with the polyvinylidene fluoride which has strong thermal oxidation resistance, it can enhance the thermal oxidation resistance of the polyphenylene sulfide composite material and prolong the service life.

[0014] Optionally, the base liquid also contains molybdenum disulfide, and the mass ratio of the molybdenum disulfide to the aramid fiber is 0.5-1:10.

[0015] By adopting the technical scheme, the molybdenum disulfide is a transition metal chalcogen compound, has a hexagonal crystal structure, and has unique physical and chemical properties. The molybdenum disulfide is added to the base liquid, adheres to the aramid fiber surface by using the adhesion of the polyvinylidene fluoride, and when the aramid fiber is blended with the polyphenylene sulfide resin, the oxidation resistance of the polyphenylene sulfide at high temperature is enhanced due to the introduction of the molybdenum-oxygen bond in the molybdenum disulfide. The molybdenum-oxygen bond has higher bond energy and can better resist the impact of heat flow to form a film, thereby further protecting the polyphenylene sulfide. In addition, the molybdenum disulfide has high thermal conductivity, can increase the thermal conductivity of the aramid fiber, increase the heat absorption and heat dissipation effect of the polyphenylene sulfide battery package shell, accelerate the heat dissipation, and reduce the thermal oxidation of the polyphenylene sulfide.

[0016] Optionally, the method for preparing the polydopamine modified carbon fiber is as follows:

[0017] The dopamine hydrochloride solution is adjusted to a pH of 8-8.5 by using a Tris-HCl buffer solution, and boron carbide and carbon aerogel are added to prepare a treatment liquid. The carbon fiber is immersed in the treatment liquid at room temperature for 22-24 hours, washed and dried, and the mass ratio of the carbon fiber, the boron carbide and the carbon aerogel is 1:0.1-0.15:0.1-0.3.

[0018] By adopting the technical scheme, the dopamine hydrochloride is subjected to a self-polymerization reaction to form polydopamine in an alkaline environment. The boron carbide and the carbon aerogel are added, and the polydopamine is adhered to load on the carbon fiber. The boron carbide has a special chemical structure, can effectively inhibit the spread of flame at high temperature, produce less harmful gas, and has good oxidation resistance, high hardness, high melting point, chemical resistance, low density and other excellent properties. At high temperature, a stable oxidation film can be formed to play an antioxidant role. The molecular structure of the boron carbide is special, and the chemical reaction between the boron carbide and the oxidizing agent is relatively slow, so that the boron carbide is not easily eroded by oxygen. The boron carbide also has excellent thermal conductivity, can rapidly conduct heat to the surface of the material, rapidly dissipate heat, and improve the flame retardation effect and the thermal oxidation resistance of the polyphenylene sulfide. The carbon aerogel is an ultralight solid material with a special three-dimensional space network structure, has excellent mechanical properties such as high bearing capacity and compression resilience, can effectively avoid structural damage caused by local stress concentration, and can improve the tensile resistance of the carbon fiber. Due to the special carbon structure and stable chemical bond of the carbon aerogel, the carbon aerogel has extremely high temperature resistance and can maintain structural stability at extremely high temperature. The high thermal stability and chemical stability can improve the thermal oxidation resistance of the high polymer material.

[0019] Optionally, the method for preparing the carbon aerogel is as follows:

[0020] The nanocellulose is dispersed into deionized water, ultrasonic, to obtain a cellulose sol, pre-freezing, freeze-drying, carbonization under nitrogen protection at 550-650℃ for 2-3h, and then crushing to obtain the base carbon aerogel with a particle size of 1-4mm;

[0021] The ten water sodium sulfate and the twelve water sodium phosphate dibasic are mixed according to a mass ratio of 1:3-4, heated to 50-55℃, and ultrasonic to prepare an impregnating solution;

[0022] The base carbon aerogel is placed in the impregnating solution and vacuum impregnated at 50-60℃ for 3-4h.

[0023] By adopting the above technical scheme, the nanocellulose is dispersed in deionized water under the action of ultrasonic, and hydrogen bonds are formed between the molecular chains to obtain a stable cellulose skeleton. A fixed three-dimensional network structure is formed during pre-freezing, and the vacuum drying further strengthens the three-dimensional structure of the cellulose aerogel. The nitrogen protection and suitable carbonization temperature during carbonization can uniformly carbonize the cellulose, and finally form a base carbon aerogel with a three-dimensional network structure and a rough surface. After carbonization, the unsaturated carbon structure increases, and the hydrophilic group of the original cellulose molecule basically disappears, which improves the hydrophobicity of the carbon aerogel to a certain extent. The ten water sodium sulfate and the twelve water sodium phosphate dibasic are both inorganic phase change materials, and the phase change temperature of the ten water sodium sulfate is 32.4℃, and the phase change temperature of the twelve water sodium phosphate dibasic is 35.1℃. The latent heat of phase change is 265kJ / kg, which is a good low-temperature energy storage material. By mixing two different phase change materials according to a specific ratio, a eutectic phase change energy storage material is obtained, and the phase change temperature is closer to the heating temperature of the battery pack shell, so that the heat of the battery pack shell is absorbed through phase change, thereby reducing the heating temperature of the battery pack shell and reducing the thermal oxidation of the polyphenylene sulfide battery pack shell.

[0024] Optionally, the impregnating solution further contains nanometer zinc oxide, and the mass ratio of nanometer zinc oxide to ten water sodium sulfate is 0.2-0.4:1.

[0025] By adopting the above technical scheme, the nanometer zinc oxide has a very high specific surface area and activity, and by being impregnated in the carbon aerogel, the thermal conductivity of the cellulose carbon aerogel can be increased, the heat exchange rate between the phase change material and the external environment can be increased, the time required for temperature rise and fall can be shortened, and the nanometer zinc oxide can also have a synergistic effect with other flame-retardant components to absorb a large amount of heat at high temperatures, reduce the surface temperature of the material, and increase the flame-retardant effect and thermal oxidation resistance.

[0026] Optionally, the toughening agent is selected from one or more of methyl methacrylate-butadiene-styrene ternary random copolymer, ethylene-methyl acrylate-glycidyl methacrylate ternary random copolymer, and maleic anhydride grafted ethylene-octene copolymer.

[0027] By adopting the technical scheme, the toughening agent is a copolymer of a plastic phase and a rubber phase, the plastic phase plays a role of being compatible with the polymer matrix, and the rubber phase plays a role of absorbing and buffering external impact force, thereby achieving a good toughening effect on the polyphenylene sulfide.

[0028] Optionally, the plasticizer is selected from one or more of trioctyl trimellitate, diethyl phthalate, methyl methacrylate and dioctyl phthalate.

[0029] By adopting the technical scheme, the plasticizer can improve the flexibility and plasticity of the polyphenylene sulfide, so that the prepared battery package shell has increased plasticity, impact resistance and crack resistance.

[0030] Optionally, the flame retardant is selected from one or more of melamine, melamine cyanurate, melamine phosphate and the like.

[0031] By adopting the technical scheme, the melamine can provide an inert gas source, dilute the density of oxygen and flammable gas generated by decomposition of the polymer, and carry away part of the heat through gas generation and thermal convection, thereby achieving a flame retardant effect. Moreover, the melamine has good compatibility with the polyphenylene sulfide resin, so that the toughening agent can be uniformly dispersed in the polyphenylene sulfide matrix, thereby improving the overall flame retardant effect of the material and helping to maintain the mechanical properties and processing properties of the material. In addition, the melamine phosphate can form a stable carbon layer when burning, thereby preventing the transmission of heat and oxygen and achieving a good flame retardant effect. Moreover, the melamine phosphate has the characteristics of low smoke and non-toxicity, and does not significantly affect the color and transparency of the material.

[0032] In a second aspect, the application provides a preparation method of a polyphenylene sulfide flame retardant material for a new energy automobile battery package shell, which adopts the following technical scheme:

[0033] The preparation method of the polyphenylene sulfide flame retardant material for the new energy automobile battery package shell comprises the following steps:

[0034] The polydopamine modified carbon fiber and the silica modified aramid fiber are mixed to obtain a modified composite fiber, and then the polyphenylene sulfide resin, the plasticizer, the toughening agent, the flame retardant, the antioxidant and the modified composite fiber are mixed to prepare a premix;

[0035] The premix is extruded, cooled and solidified, and then pelletized to prepare the polyphenylene sulfide flame retardant material.

[0036] By adopting the above technical scheme, the raw materials are uniformly mixed and then extruded, thereby avoiding the problems of uneven melting and fiber floating on the outer surface of the material when the inorganic filler is added from the side feeding port.

[0037] In summary, the application has the following beneficial effects:

[0038] 1、Due to the combination of polydopamine modified carbon fiber and silica modified aramid fiber in the application as modified composite fiber, after modification by polydopamine, the wettability of carbon fiber with polyphenylene sulfide resin matrix is improved, and the compatibility of silica modified aramid fiber with polyphenylene sulfide resin is also increased, so that the carbon fiber and aramid fiber are uniformly dispersed in the polyphenylene sulfide resin matrix, the brittleness is reduced, the flexibility is increased, and the impact resistance and bending resistance are improved.

[0039] 2、In the application, the dispersibility of silica modified by silane coupling agent KH550 in polyvinylidene fluoride is preferred, and then the adhesion of polyvinylidene fluoride is used to load modified silica on aramid fiber, increase the roughness of aramid fiber surface, improve the wettability of polyphenylene sulfide to it, in addition, silica and polyvinylidene fluoride can further improve the heat oxidation resistance of polyphenylene sulfide, prolong the service life of battery package shell and reduce the possibility of thermal oxidation and brittleness.

[0040] 3、In the application, polydopamine is preferably used to load boron carbide and carbon aerogel on the surface of carbon fiber, which increases the compatibility of carbon fiber in polyphenylene sulfide, and boron carbide and carbon aerogel further improve the heat oxidation resistance of polyphenylene sulfide, preventing the thermal oxidation and brittleness of polyphenylene sulfide battery package shell. DETAILED DESCRIPTION

[0041] The following examples further illustrate the application.

[0042] Preparation examples 1-6 of silica modified aramid fiber

[0043] Preparation example 1: 15g of silica was dispersed in 15g of deionized water, mixed uniformly, and then sprayed on 100g of aramid fiber, vacuum dried at 80℃, the particle size of nano-silica was 50±5nm, and the aramid fiber was selected from Hubei Tengdi New Material, with the product number TD240730 and the length of 6mm.

[0044] Preparation example 2: (1) 2g of silane coupling agent KH550, ethanol and deionized water were mixed according to the mass ratio of 2:78:20, the pH was adjusted to 5 with glacial acetic acid, nano-silica was added, and the modification was immersed at 30℃ for 1h, and vacuum dried at 70℃ for 24h to obtain modified nano-silica, the particle size of nano-silica was 50±5nm;

[0045] (2) 1.5g of polyvinylidene fluoride was dissolved with DMF to obtain a base solution with a concentration of 10wt%, 15g of modified nano-silica was added, and then sprayed on 100g of aramid fiber after mixing uniformly, vacuum dried at 80℃ for 6h, the type of polyvinylidene fluoride was FR904, Mn=4.5x10 5g / mol, crystallinity 32.13%, selected from Shanghai Sanai Fu Material, aramid fiber selected from Hubei Tengdi New Material, with the model number TD240730, length 6 mm.

[0046] Preparation Example 3: (1) 2 g of silane coupling agent KH550, ethanol and deionized water were mixed in a mass ratio of 2:78:20, and the pH was adjusted to 5.5 with glacial acetic acid. Nano-silica was added, and the modified nano-silica was prepared by dipping at 40°C for 2 h and vacuum drying at 70°C for 24 h. The particle size of the nano-silica was 50±5 nm;

[0047] (2) 1 g of polyvinylidene fluoride was dissolved in DMF to obtain a base solution with a concentration of 10 wt%, and 10 g of modified nano-silica was added. After mixing evenly, it was sprayed on 100 g of aramid fiber and vacuum dried at 70°C for 8 h. The polyvinylidene fluoride was FR904, Mn = 4.5 x 10 5 g / mol, crystallinity 32.13%, selected from Shanghai Sanai Fu Material, aramid fiber selected from Hubei Tengdi New Material, with the model number TD240730, length 6 mm.

[0048] Preparation Example 4: The difference from Preparation Example 2 is that an equal amount of deionized water is used instead of the base solution.

[0049] Preparation Example 5: The difference from Preparation Example 2 is that 10 g of molybdenum disulfide is also added to the base solution, and the mass ratio of molybdenum disulfide to aramid fiber is 1:10.

[0050] Preparation Example 6: The difference from Preparation Example 2 is that 5 g of molybdenum disulfide is also added to the base solution, and the mass ratio of molybdenum disulfide to aramid fiber is 0.5:10.

[0051] Preparation Examples 7-14 of polydopamine-modified carbon fibers

[0052] Preparation Example 7: (1) 1000 g of a 2 g / l dopamine hydrochloride solution was adjusted to pH 8.5 with a 0.01 mol / l Tris-HCl buffer solution to obtain a treatment solution;

[0053] (2) 100 carbon fibers were immersed in the treatment solution at room temperature for 24 h, washed with distilled water, and dried at 50°C for 24 h. The length of the carbon fibers was 3 mm.

[0054] Preparation Example 8: (1) 1000 g of a dopamine hydrochloride solution with a concentration of 2 g / l was adjusted to pH 8.5 with a 0.01 mol / l Tris-HCl buffer solution, 15 g of boron carbide and 30 g of carbon aerogel were added to obtain a treatment liquid, the carbon aerogel was prepared by the following method: 1 g of nanocellulose was dispersed in 100 ml of deionized water, ultrasonic treatment was performed at a power of 350 W for 30 min to obtain a cellulose sol, pre-freezing was performed at -20℃ for 24 h, then freeze-drying was performed at -30℃ for 48 h, under the protection of nitrogen, the temperature was raised to 600℃ at a rate of 5℃ / min, carbonization was performed for 2 h, and then crushing was performed to obtain carbon aerogel with a particle size of 4 mm, the boron carbide was selected from Anhui Nanhu Electronics Technology, model B4C;

[0055] (2) 100 g of carbon fibers were immersed in the treatment liquid at room temperature for 24 h, washed with distilled water, and dried at 50℃ for 24 h, the length of the carbon fibers was 3 mm.

[0056] Preparation Example 9: (1) 1000 g of a dopamine hydrochloride solution with a concentration of 2 g / l was adjusted to pH 8.5 with a 0.01 mol / l Tris-HCl buffer solution, 10 g of boron carbide and 10 g of carbon aerogel were added to obtain a treatment liquid, the carbon aerogel was prepared by the following method: 1 g of nanocellulose was dispersed in 100 ml of deionized water, ultrasonic treatment was performed at a power of 350 W for 30 min to obtain a cellulose sol, pre-freezing was performed at -20℃ for 24 h, then freeze-drying was performed at -30℃ for 48 h, under the protection of nitrogen, the temperature was raised to 550℃ at a rate of 5℃ / min, carbonization was performed for 3 h, and then crushing was performed to obtain carbon aerogel with a particle size of 1 mm, the boron carbide was selected from Anhui Nanhu Electronics Technology, model B4C;

[0057] (2) 100 g of carbon fibers were immersed in the treatment liquid at room temperature for 22 h, washed with distilled water, and dried at 50℃ for 24 h, the length of the carbon fibers was 3 mm.

[0058] Preparation Example 10: The difference from Preparation Example 8 is that no boron carbide is added.

[0059] Preparation Example 11: The difference from Preparation Example 8 is that no carbon aerogel is added.

[0060] Preparation Example 12: The difference from Preparation Example 8 is that the carbon aerogel is prepared by the following method: the carbon aerogel is prepared by the following method: 1 g of nanocellulose is dispersed in 100 ml of deionized water, ultrasonic treatment is performed at a power of 350 W for 30 min to obtain a cellulose sol, pre-freezing is performed at -20℃ for 24 h, then freeze-drying is performed at -30℃ for 48 h, under the protection of nitrogen, the temperature is raised to 600℃ at a rate of 5℃ / min, carbonization is performed for 2 h, and then crushing is performed to obtain basic carbon aerogel with a particle size of 4 mm;

[0061] Sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate and nano zinc oxide were mixed in a mass ratio of 1:3:0.4, heated to 55℃, and ultrasonicated for 30 min to prepare the impregnating solution;

[0062] The base carbon aerogel was placed in the impregnating solution and vacuum impregnated at 50℃ for 4h.

[0063] Preparation Example 13: The difference from Preparation Example 8 is that the carbon aerogel is prepared by the following method: 1g of nanocellulose is dispersed in 100ml of deionized water, ultrasonicated at 350W power for 30min to obtain a cellulose sol, pre-frozen at-20℃ for 24h, then freeze-dried at-30℃ for 48h, heated to 550℃ at 5℃ / min under nitrogen protection, carbonized for 3h, then crushed to obtain a base carbon aerogel with a particle size of 4mm;

[0064] Sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate and nano zinc oxide were mixed in a mass ratio of 1:3:0.4, heated to 55℃, and ultrasonicated for 30 min to prepare the impregnating solution;

[0065] The base carbon aerogel was placed in the impregnating solution and vacuum impregnated at 50℃ for 4h.

[0066] Preparation Example 14: The difference from Preparation Example 12 is that no nano zinc oxide is added.

[0067] Example

[0068] Example 1: A new energy automobile battery pack shell polyphenylene sulfide flame retardant material, the amount of raw materials is shown in Table 1, wherein the polyphenylene sulfide resin is selected from Japan Toray, model A900, plasticizer is tris (octyl) trimellitate, selected from Shandong Yuxiao Chemical Technology, model TOTM, toughening agent is methyl methacrylate-butadiene-styrene ternary random copolymer (MBS), selected from Ningbo Jiuli New Material, model EM500, serial number 1037, flame retardant is melamine, antioxidant is antioxidant 1010, modified composite fiber includes polydopamine modified carbon fiber and silicon dioxide modified aramid fiber with a mass ratio of 1:1, silicon dioxide modified aramid fiber is made by Preparation Example 1, and polydopamine modified carbon fiber is made by Preparation Example 7.

[0069] The preparation method of the above-mentioned new energy automobile battery pack shell polyphenylene sulfide flame retardant material includes the following steps:

[0070] S1, mix the polydopamine modified carbon fiber and the silicon dioxide modified aramid fiber to obtain a modified composite fiber, then mix the polyphenylene sulfide resin, the plasticizer, the toughening agent, the flame retardant, the antioxidant and the modified composite fiber at a stirring speed of 100rpm for 3h to prepare a premix;

[0071] S2, the premix is extruded, cooled and solidified, and granulated to prepare the polyphenylene sulfide flame-retardant material, the extrusion temperature is 290°C, and the screw rotation speed is 300 rpm.

[0072] Table 1 Raw material ratio of polyphenylene sulfide flame-retardant material for new energy automobile battery pack shell

[0073]

[0074]

[0075] Example 2: A polyphenylene sulfide flame-retardant material for a new energy automobile battery pack shell, the raw material usage is shown in Table 1, wherein the polyphenylene sulfide resin is selected from Japan Toray, model A900, the plasticizer is diethyl phthalate, the toughening agent is ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA) selected from Arkema, model AX8900, the flame retardant is melamine cyanurate selected from Jiangsu Xinsu New Material, model MAC, the antioxidant is antioxidant 1010, and the modified composite fiber includes polydopamine modified carbon fiber and silica modified aramid fiber with a mass ratio of 1:0.8, the silica modified aramid fiber is prepared in Preparation Example 1, and the polydopamine modified carbon fiber is prepared in Preparation Example 7.

[0076] The preparation method of the polyphenylene sulfide flame-retardant material for a new energy automobile battery pack shell, including the following steps:

[0077] S1, the polyphenylene sulfide resin, the plasticizer, the toughening agent, the flame retardant, the antioxidant and the modified composite fiber are mixed to prepare a premix; S2, the premix is extruded, cooled and solidified, and granulated to prepare the polyphenylene sulfide flame-retardant material, the extrusion temperature is 300°C, and the screw rotation speed is 300 rpm.

[0078] Example 3: A polyphenylene sulfide flame-retardant material for a new energy automobile battery pack shell, the raw material usage is shown in Table 1, wherein the polyphenylene sulfide resin is selected from Japan Toray, model A900, the plasticizer is methyl methacrylate, the toughening agent is maleic anhydride grafted ethylene-octene copolymer (POE-g-MAH) selected from American Dow, model M2265, the flame retardant is melamine and melamine cyanurate with a mass ratio of 1:1, the melamine cyanurate is selected from Jiangsu Xinsu New Material, model MAC, the antioxidant is antioxidant 1010, and the modified composite fiber includes polydopamine modified carbon fiber and silica modified aramid fiber with a mass ratio of 1:1, the silica modified aramid fiber is prepared in Preparation Example 1, and the polydopamine modified carbon fiber is prepared in Preparation Example 7.

[0079] The preparation method of the polyphenylene sulfide flame-retardant material for a new energy automobile battery pack shell, including the following steps:

[0080] S1, polyphenylene sulfide resin, plasticizer, toughening agent, flame retardant, antioxidant and modified composite fiber are mixed to prepare a premix; S2, the premix is extruded, cooled and solidified, and then granulated to prepare a polyphenylene sulfide flame retardant material, the extrusion temperature is 300℃, and the screw rotation speed is 300rpm.

[0081] Examples 4-8: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 1 in that the preparation example of the silica modified aramid fiber is selected as shown in table 2.

[0082] Examples 9-15: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 4 in that the preparation example of the polydopamine modified carbon fiber is selected as shown in table 2.

[0083] Table 2: Selection of silica modified aramid fiber and polydopamine modified carbon fiber in examples 5-15

[0084] Embodiment Silica-modified aramid fibers Polydopamine-modified carbon fibers Embodiment 4 Preparation Example 2 Preparation Example 7 Embodiment 5 Preparation Example 3 Preparation Example 7 Embodiment 6 Preparation Example 4 Preparation Example 7 Embodiment 7 Preparation Example 5 Preparation Example 7 Embodiment 8 Preparation Example 6 Preparation Example 7 Embodiment 9 Preparation Example 2 Preparation Example 8 Embodiment 10 Preparation Example 2 Preparation Example 9 Embodiment 11 Preparation Example 2 Preparation Example 10 Embodiment 12 Preparation Example 2 Preparation Example 11 Embodiment 13 Preparation Example 2 Preparation Example 12 Embodiment 14 Preparation Example 2 Preparation Example 13 Embodiment 15 Preparation Example 2 Preparation Example 14

[0085] Comparative example

[0086] Comparative example 1: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 1 in that an equal amount of polydopamine modified carbon fiber is used to replace the silica modified aramid fiber.

[0087] Comparative example 2: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 1 in that the aramid fiber is not modified by silica.

[0088] Comparative example 3: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 1 in that no silica modified aramid fiber is added.

[0089] Comparative example 4: A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, which is different from example 1 in that an equal amount of glass fiber is used to replace the modified composite fiber.

[0090] Performance detection test

[0091] The polyphenylene sulfide flame retardant material is prepared according to the method in the examples and comparative examples, and the performance is detected according to the following method, and the detection results are recorded in table 3.

[0092] 1, Tensile properties: tested according to GB / T1040-2006 "Plastics - Determination of tensile properties - Method of test".

[0093] 2, Impact properties: tested according to GB / T1043-1993 "Rigid plastics - Charpy impact test method".

[0094] 3. Flexural strength: tested according to GB / T9341-2008 "Determination of flexural properties of plastics".

[0095] 3. Flame retardant property: tested according to GB / T2406-1993 "Standard test methods for measuring the flammability of plastic (oxygen index method)".

[0096] 4. Thermal oxidative resistance: the prepared polyphenylene sulfide material was placed at 200℃ for 72h, then the tensile strength was detected again, and the strength retention rate was calculated.

[0097] Table 3 Performance test results of polyphenylene sulfide flame retardant material

[0098]

[0099] As can be seen from Examples 1-3 and the data in Table 3, by using a specific amount of polydopamine modified carbon fiber and silica modified aramid fiber, the prepared polyphenylene sulfide composite material has high flexural strength and impact resistance, good toughness, is not easy to produce fragmentation, and has high oxygen index and good flame retardancy.

[0100] In Examples 4 and 5, the silica modified aramid fiber prepared by Preparation Example 2 and Preparation Example 3 is used respectively, and in Example 6, the silica modified aramid fiber prepared by Preparation Example 4 is used. Compared with Example 4, the base liquid made of polyvinylidene fluoride is not used as a binder, and as shown in Table 3, the thermal oxidation capacity of the polyphenylene sulfide flame retardant material decreases, and the flexural strength and impact strength decrease slightly, indicating that polyvinylidene fluoride can increase the interfacial bonding strength of the silica and aramid fiber surface, thereby increasing the surface roughness of the aramid fiber and improving the embedding degree of the aramid fiber with the polyphenylene sulfide matrix resin, thereby improving the improvement effect of the aramid fiber on the mechanical strength.

[0101] Compared with Example 4, Examples 7 and 8 use the silica modified aramid fiber prepared by Preparation Example 5 and Preparation Example 6 respectively, and the data in Table 3 shows that the strength retention rate of the polyphenylene sulfide flame retardant material increases after high temperature oxidation, and the impact strength is high, and the flame retardant effect is slightly improved.

[0102] In Examples 9 and 10, the silica modified aramid fiber prepared by Preparation Example 2 is used, and the polydopamine modified carbon fiber prepared by Preparation Example 8 and Preparation Example 9 is used respectively, and compared with Preparation Example 7, boron carbide and carbon aerogel are also used in Preparation Example 8 and Preparation Example 9, and as shown in Table 3, compared with Example 4, the oxygen index of the polyphenylene sulfide flame retardant material prepared in Examples 9 and 10 increases, the strength retention increases, and the bending resistance and impact resistance are further improved.

[0103] The polydopamine modified carbon fiber prepared in Preparation Example 10 and Preparation Example 11 is used in Example 11 and Example 12 respectively, compared with Preparation Example 8, boron carbide and carbon aerogel are not added in Preparation Example 10 and Preparation Example 11 respectively, as shown in Table 3, compared with Example 9, the decrease of tensile strength, bending strength and impact strength in Example 11 is not too obvious, but the decrease of oxygen index and strength retention rate is significant, which indicates that boron carbide can improve the heat resistance of the material, the change of oxygen index in Example 12 is not large, but the mechanical properties such as tensile strength and the strength retention rate are significantly decreased, which indicates that carbon aerogel can significantly improve the mechanical properties and heat oxidation resistance of polyphenylene sulfide composite material.

[0104] The polydopamine modified carbon fiber prepared in Preparation Example 12 and Preparation Example 13 is used in Example 13 and Example 14 respectively, as shown in Table 3, the heat oxidation resistance of polyphenylene sulfide flame-retardant material prepared in Example 13 and Example 14 is enhanced, which indicates that the addition of sodium sulfate decahydrate and disodium hydrogen phosphate dodecahydrate can improve the heat absorption effect of carbon aerogel and reduce heat.

[0105] The polydopamine modified carbon fiber prepared in Preparation Example 14 is used in Preparation Example 15, compared with Preparation Example 12, nano zinc oxide is not added, as shown in Table 3, the heat oxidation resistance of polyphenylene sulfide flame-retardant material prepared in Example 15 is weakened, and the rest of the performance is not much different from that of Example 13.

[0106] Comparative Example 1 uses polydopamine modified carbon fiber instead of silica modified aramid fiber compared with Example 1, as shown in Table 3, the polyphenylene sulfide flame-retardant material prepared in Comparative Example 1 has good flame-retardant performance, but the tensile resistance, bending resistance, impact resistance and heat oxidation resistance are decreased.

[0107] Polydopamine modified carbon fiber and aramid fiber are used in Comparative Example 2, the aramid fiber is not modified by silica, as shown in Table 3, compared with Example 1, the heat oxidation resistance of polyphenylene sulfide material prepared in Comparative Example 2 is decreased, the impact resistance and bending resistance are weakened, and the heat oxidation resistance is weakened.

[0108] Silica modified aramid fiber is not added in Comparative Example 3, which reduces the amount of modified composite fiber, compared with Example 1, the performance of polyphenylene sulfide material prepared in Comparative Example 3 is decreased, and glass fiber is used instead of modified composite fiber in Comparative Example 4, which has good flame-retardant effect, but the bending resistance and impact resistance are significantly decreased.

[0109] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A polyphenylene sulfide flame retardant material for a new energy automobile battery pack shell, characterized in that, The raw materials include the following components by weight: 50-70 parts of polyphenylene sulfide resin, 1-3 parts of plasticizer, 2-6 parts of toughening agent, 2-3 parts of flame retardant, 0.1-1 part of antioxidant and 30-50 parts of modified composite fiber; The modified composite fiber comprises polydopamine modified carbon fiber and silica modified aramid fiber in a mass ratio of 1:0.8-1.

2. The polyphenylene sulfide flame retardant material for new energy vehicle battery pack shell according to claim 1, characterized in that: The method for preparing the silica modified aramid fiber is as follows: The silane coupling agent KH550, ethanol and deionized water are mixed, the pH is adjusted to 5-5.5, nano-silica is added, and the modified nano-silica is prepared by dipping at 30-40℃ for 1-2h and vacuum drying. The polyvinylidene fluoride is dissolved to form a base solution with a concentration of 10wt%, the modified nano-silica is added to the base solution, and the aramid fiber is sprayed after mixing, and vacuum dried at 70-80℃, the mass ratio of aramid fiber, modified nano-silica and polyvinylidene fluoride is 10:1-1.5:0.1-0.

15.

3. The polyphenylene sulfide flame retardant material for new energy vehicle battery pack shell according to claim 2, characterized in that: The base solution also contains molybdenum disulfide, and the mass ratio of molybdenum disulfide to aramid fiber is 0.5-1:

10.

4. The polyphenylene sulfide flame retardant material for new energy vehicle battery pack shell according to claim 1, characterized in that: The method for preparing the polydopamine modified carbon fiber is as follows: The hydrochloric acid dopamine solution is adjusted to pH 8-8.5 with Tris-HCl buffer, and boron carbide and carbon aerogel are added to prepare a treatment solution. The carbon fiber is dipped in the treatment solution at room temperature for 22-24h, washed and dried, and the mass ratio of carbon fiber, boron carbide and carbon aerogel is 1:0.1-0.15:0.1-0.

3.

5. The polyphenylene sulfide flame retardant material for new energy vehicle battery pack shell according to claim 4, characterized in that: The method for preparing the carbon aerogel is as follows: The nanocellulose is dispersed in deionized water and ultrasonicated to obtain a cellulose sol, and then the cellulose sol is pre-frozen, freeze-dried, carbonized at 550-650℃ under nitrogen protection for 2-3h, and then crushed to obtain a base carbon aerogel with a particle size of 1-4mm. Sodium sulfate decahydrate and sodium phosphate dibasic dodecahydrate are mixed in a mass ratio of 1:3-4, heated to 50-55℃, and ultrasonicated to prepare an impregnation solution. The base carbon aerogel is placed in the impregnation solution and vacuum impregnated at 50-60℃ for 3-4h.

6. The new energy vehicle battery pack shell use polyphenylene sulfide flame retardant material of claim 5, characterized in that: The impregnation solution also contains nano-zinc oxide, and the mass ratio of nano-zinc oxide to sodium sulfate decahydrate is 0.2-0.4:

1.

7. The new energy vehicle battery pack shell use polyphenylene sulfide flame retardant material of claim 1, characterized in that: The toughening agent is selected from one or more of methyl methacrylate-butadiene-styrene ternary random copolymer, ethylene-methyl acrylate-glycidyl methacrylate ternary random copolymer, and maleic anhydride grafted ethylene-octene copolymer. 8.The polyphenylene sulfide flame-retardant material for new energy vehicle battery pack shell according to claim 1, characterized in that: The plasticizer is selected from one or more of trioctyl trimellitate, diethyl phthalate, methyl methacrylate and dioctyl phthalate. 9.The polyphenylene sulfide flame-retardant material for new energy vehicle battery pack shell according to claim 1, characterized in that: The flame retardant is selected from one or more of melamine, melamine cyanurate, melamine phosphate and the like.

10. The method of producing a polyphenylene sulfide flame retardant material for a new energy vehicle battery pack housing according to any one of claims 1 to 9, characterized by: The method comprises the following steps: The polydopamine modified carbon fiber and the silica modified aramid fiber are mixed to obtain a modified composite fiber, and then the polyphenylene sulfide resin, the plasticizer, the toughening agent, the flame retardant, the antioxidant and the modified composite fiber are mixed to prepare a premix; The premix is extruded, cooled and solidified, and then pelletized to prepare a polyphenylene sulfide flame retardant material.

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