Reinforced polyphenylene sulfide composite material for battery cover plate and its preparation method

Abstract

The present invention relates to a reinforced polyphenylene sulfide composite material for a battery cover plate and a preparation method thereof, which comprises the following components in parts by weight: 20-40 parts of polyphenylene sulfide; 1-5 parts of compatibilizer; 1-3 parts of resin crosslinking agent; 35-50 parts of glass fiber; 10-30 parts of mineral whisker; 0.5-2 parts of acid absorbent; the compatibilizer is glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer, and the grafting rate of glycidyl methacrylate is 2-3%; the polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent are mixed evenly to obtain a mixture, and the mixture and the glass fiber are respectively added from the main feeding port and the side feeding port of a twin-screw extruder for melt extrusion granulation to prepare the reinforced polyphenylene sulfide composite material for the battery cover plate. The product has good mechanical strength, and the linear expansion coefficient is close to that of metallic aluminum; the method of the present invention is simple, and the prepared product has good dimensional stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery covers, and relates to a reinforced polyphenylene sulfide composite material for battery covers and a preparation method thereof. Background Art

[0002] Power batteries are the core components of electric vehicles, and the battery has high requirements for safety and cycle life. Among them, the battery cover is one of the important accessories.

[0003] At present, the battery electrode plate is integrally injection-molded with plastic and metal. In actual application, after the single battery undergoes multiple cold and hot cycles of power on and off, a large gap is generated at the connection between the metal part and the insulating plastic, affecting the contact, which will further increase the contact resistance. As the contact resistance increases, the temperature rises, which causes the corrosion and oxidation of the battery at high temperature to intensify, resulting in a vicious cycle, reducing the connection reliability. The excessive temperature at the connection part (including the cover) will cause smoking and the connecting piece to break, affecting the life and performance of the battery pack. Therefore, the battery cover needs to have high strength, high temperature resistance and high dimensional stability.

[0004] PPS (polyphenylene sulfide) is a type of thermoplastic polymer with phenylthio groups on the main chain, having excellent high temperature resistance, corrosion resistance, radiation resistance, flame retardancy, and balanced physical and mechanical properties. PPS reinforced with glass fiber has high heat resistance and mechanical strength and is an ideal material for battery plates. However, since PPS is a crystalline material, after adding fiber filling, the fiber orientation causes shrinkage deformation and poor surface flatness. After high and low temperature cycling, due to the inconsistent expansion coefficients of the insert metal and the plastic, and the poor ductility of the plastic, problems such as metal-plastic separation, airtightness damage, and stress cracking are likely to occur in the high and low temperature cycling environment, greatly affecting the product yield and safety, and the actual use is greatly affected.

[0005] Chinese invention CN103772987A discloses a high-strength and low-warpage modified polyphenylene sulfide material and a preparation method thereof. The modified polyphenylene sulfide material is made of the following components in parts by weight: 60-85 parts of polyphenylene sulfide, 10-30 parts of glass fiber, 5-10 parts of kaolin, 0.3-0.6 parts of lubricant, 0.3-0.6 parts of antioxidant, and 0.6-1 part of coupling agent. The prepared polyphenylene sulfide composite material has characteristics such as high strength and heat resistance, but its linear expansion coefficient is relatively high. After high and low temperature cycling, the size changes greatly and the airtightness becomes poor, which is not suitable for battery plate applications.

[0006] Therefore, it is necessary to study a reinforced polyphenylene sulfide composite material for battery covers and a preparation method thereof to solve the problem of poor dimensional stability of PPS composite with glass fiber in the prior art. Summary of the Invention

[0007] The object of the present invention is to solve the problems existing in the prior art and provide a reinforced polyphenylene sulfide composite material for battery covers and a preparation method thereof.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A reinforced polyphenylene sulfide (PPS) composite material for battery covers comprises the following components in parts by weight:

[0010]

[0011] The compatibilizer is glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer (SEBS-g-GMA); the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer is 2-3%;

[0012] The resin crosslinking agent is thermoplastic phenoxy resin (PKHH);

[0013] The acid absorbent is nanolayered structure hydrotalcite;

[0014] Due to the presence of benzene rings and hydroxyl ether bonds in the molecular main chain of PKHH resin, it has excellent mechanical strength and toughness. Due to the presence of a large number of hydroxyl groups, it can not only react with the surface of inorganic substances (glass fiber and whiskers mentioned in the present invention) to improve the binding force with the resin, but also react with the epoxy functional groups of SEBS-g-GMA to achieve the effect of co-toughening and synergistic effect;

[0015] The SEBS-g-GMA used in the present invention has a grafting rate of 2-3%, and its GMA content is excessive. A part of it participates in the toughening reaction of phenoxy resin (PKHH) and PPS molecular chains. At a high temperature of 290 °C, there are unreacted GMA functional groups that undergo micro-crosslinking reactions with the molecular chains to form a macromolecular chain network structure, making the movement ability of PPS molecular chains weaker, and thus the shrinkage of the material decreases, resulting in a lower linear expansion coefficient of the material;

[0016] During the synthesis of PPS, there will inevitably be residues of halogenated metal salts. These free acidic substances will cause metal corrosion and affect the battery life and safety. Utilizing the strong polar ion exchange characteristics of the nanolayered structure of hydrotalcite, impurities such as chloride ions are fixed between the layers without generating by-product impurities, which is beneficial to improving the safety characteristics of battery use.

[0017] As a preferred technical solution:

[0018] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the resin crosslinking agent is dissolved in cyclohexane to prepare a solution with a concentration of 20 wt%, the viscosity measured at 25 °C is 500-750 mPa·s, and the weight average molecular weight is 30,000-60,000.

[0019] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the BET surface area of the nanolayered structure hydrotalcite is greater than 10 m 2 / g, the D50 particle size is 0.2-0.5 μm, and the proportion of particles with a particle size less than 1 μm in the nanolayered structure hydrotalcite is > 90%.

[0020] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the polyphenylene sulfide is linear polyphenylene sulfide, and the melt index under the conditions of 316 °C * 5 kg is 600-1500 g / 10 min, preferably 800-1200 g / 10 min, and more preferably 800-1000 g / 10 min; Linear polyphenylene sulfide as the base material has higher toughness and flowability compared with crosslinked polyphenylene sulfide. Especially when applied through high and low temperature cycles, it has better ductility. Selecting high melt index linear polyphenylene sulfide helps to improve the dispersion of mineral fillers, and improve the flatness and mechanical strength of the material.

[0021] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the glass fiber is a special-shaped glass fiber with a non-circular cross-section, and its aspect ratio is 1:2; Selecting this aspect ratio, compared with general glass fibers, not only has a larger surface contact ability, but also the combination of its own flat structure and mineral whiskers makes the material have higher strength and better anisotropy, and the transverse and longitudinal dimensions of the material are more stable and the flatness is better.

[0022] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the mineral whisker is one or more of zinc oxide whiskers, magnesium borate whiskers, calcium sulfate whiskers, magnesium sulfate whiskers and potassium titanate whiskers, preferably zinc oxide whiskers; The surface of the mineral whisker is treated with a silane KH-570 coupling agent; The mineral crystal has a specific needle-like structure and good fluidity, which can improve the surface smoothness of the product. Compared with the most common anisotropic glass microspheres, it has less damage to the mechanical properties of the material; Zinc oxide whiskers have a unique three-dimensional four-needle structure, which can isotropically improve the mechanical properties of the material and have a lower expansion coefficient.

[0023] An enhanced polyphenylene sulfide composite material for a battery cover plate as described above, wherein the zinc oxide whisker is a four-needle whisker, and the diameter of each needle-like part is 0.5-5 μm and the length is 10-50 μm.

[0024] The present invention also provides an enhanced polyphenylene sulfide composite material for a battery cover plate as described in any one of the above, comprising the following steps:

[0025] (1) Mix polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent in a high-speed mixer for 3 - 5 minutes, and then discharge to obtain a mixture.

[0026] (2) Feed the mixture obtained in step (1) into the main feeding port of a twin-screw extruder, and feed glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder at 290 - 320 °C and the screw rotation speed at 180 - 600 revolutions per minute, and perform extrusion granulation to obtain the reinforced polyphenylene sulfide composite material for battery cover plates.

[0027] Beneficial effects:

[0028] (1) The reinforced polyphenylene sulfide composite material for battery cover plates of the present invention has good mechanical strength, high surface flatness, and a coefficient of thermal expansion close to that of metallic aluminum, and is particularly suitable for structural components that require good bonding ability with metallic aluminum.

[0029] (2) In the preparation method of the reinforced polyphenylene sulfide composite material for battery cover plates of the present invention, the grafting rate of SEBS-g-GMA is 2 - 3%, and the content of GMA is in excess. A part of it participates in the toughening reaction of the phenoxy resin (PKHH) and PPS molecular chains. At a high temperature of 290 °C, unreacted GMA functional groups react with the molecular chains to undergo a micro-crosslinking reaction, forming a macromolecular chain network structure, weakening the movement ability of the PPS molecular chains, thereby reducing the shrinkage of the material and making the material have a lower linear expansion coefficient.

[0030] (3) In the preparation method of the reinforced polyphenylene sulfide composite material for battery cover plates of the present invention, by utilizing the strong polar ion exchange characteristics of the hydrotalcite nanolayered structure, impurities such as chloride ions are fixed between the layers without generating by-product impurities, which is beneficial to improving the safety characteristics of battery use. Specific embodiments

[0031] The following further elaborates the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0032] The test methods related to the embodiments of the present invention are as follows:

[0033] Tensile strength and tensile modulus: Test according to ISO 527 standard;

[0034] Notched impact strength: Test according to ISO 179 standard;

[0035] Transverse shrinkage rate, longitudinal shrinkage rate: Tested in accordance with ISO 294 standard;

[0036] Coefficient of linear expansion: Tested in accordance with ASTM D696 standard.

[0037] Example 1

[0038] A preparation method of a reinforced polyphenylene sulfide composite material for a battery cover plate, the specific steps are as follows:

[0039] (1) Preparation of raw materials:

[0040] Polyphenylene sulfide: Linear polyphenylene sulfide, melt index of 1000 g / 10 min under the conditions of 316 °C * 5 kg, manufacturer: Chongqing Jushi New Material Technology Co., Ltd., grade: GAC08;

[0041] Compatibilizer: Glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer, wherein the grafting rate of glycidyl methacrylate is 2-3%, manufacturer: Jiarong Polymer (Shanghai) Co., Ltd., grade: SEBG-03;

[0042] Resin crosslinking agent: Thermoplastic phenoxy resin, manufacturer: Union Carbide Resin PKHH of the United States, weight average molecular weight of 52000, dissolve the resin crosslinking agent in cyclohexane to prepare a solution with a concentration of 20 wt%, and the viscosity measured at 25 °C is 600 mPa.s;

[0043] Glass fiber: Special-shaped glass fiber with a non-circular cross-section, aspect ratio of 1:2, manufacturer: Nittobo Company of Japan, model: Special-shaped glass fiber FF (Ratio2);

[0044] Mineral whisker: Tetrapod-shaped zinc oxide whisker treated with silane KH-570 coupling agent, and the diameter of each needle-shaped part is 0.5-5 μm, length is 10-50 μm;

[0045] Acid absorbent: Nano-layered structure hydrotalcite, BET surface area of nano-layered structure hydrotalcite is greater than 10 m 2 / g, D50 particle size is 0.2-0.5 μm, and the proportion of particles with a particle size less than 1 μm in nano-layered structure hydrotalcite is >90%, manufacturer: Clariant, model: Hycite713;

[0046] By weight, it includes 34 parts of polyphenylene sulfide, 3 parts of compatibilizer, 2 parts of resin crosslinking agent, 25 parts of mineral whisker, 1 part of acid absorbent and 35 parts of glass fiber;

[0047] (2) Mix polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent in a high-speed mixer for 3-5 minutes and then discharge to obtain a mixture;

[0048] (3) Feed the mixture obtained in step (2) into the main feeding port of the twin-screw extruder, and feed glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder to be 290-320 °C and the screw rotation speed to be 180-600 revolutions per minute, and carry out extrusion granulation to obtain the reinforced polyphenylene sulfide composite material for battery cover plates.

[0049] The tensile strength of the finally obtained reinforced polyphenylene sulfide composite material for battery cover plates is 145 MPa, the tensile modulus is 16400 MPa, and the notch impact strength is 7.5 KJ / m 2 , the transverse shrinkage rate is 0.25%, the longitudinal shrinkage rate is 0.28%, and the linear expansion coefficient is 24.5*10 -6 mm / mm*°C.

[0050] Comparative Example 1

[0051] A preparation method of a polyphenylene sulfide composite material is basically the same as that of Example 1, except that the resin cross-linking agent is omitted.

[0052] The tensile strength of the finally obtained polyphenylene sulfide composite material is 142 MPa, the tensile modulus is 16700 MPa, and the notch impact strength is 6.4 KJ / m 2 , the transverse shrinkage rate is 0.29%, the longitudinal shrinkage rate is 0.33%, and the linear expansion coefficient is 27.6*10- 6 mm / mm*°C.

[0053] Comparing Comparative Example 1 with Example 1, it can be seen that in addition to the decrease in impact performance, the deviation of the transverse and longitudinal shrinkage rates increases, the flatness decreases, and the linear expansion coefficient is too large. This is because without the synergistic toughening effect of PKHH, the toughening performance decreases. More importantly, without the micro-crosslinking reaction of PKHH with SEBS-g-GMA and PPS molecular chains, the movement ability of PPS molecular chains is limited, and the PPS molecular chains still have strong activity ability, and then the size changes greatly with the change of temperature.

[0054] Comparative Example 2

[0055] A preparation method of a polyphenylene sulfide composite material is basically the same as that of Example 1, except that the compatibilizer is replaced with FG1901 (SEBS-g-MAH, grafting rate is 1.4-2%) of Kraton in the United States.

[0056] The tensile strength of the finally obtained polyphenylene sulfide composite material is 138 MPa, the tensile modulus is 15760 MPa, and the notch impact strength is 6.1 KJ / m 2 , the transverse shrinkage rate is 0.27%, the longitudinal shrinkage rate is 0.34%, and the linear expansion coefficient is 26.4*10 -6mm / mm*℃。

[0057] Comparing Comparative Example 2 with Example 1, it can be seen that the deviation of the transverse and longitudinal shrinkage rates increases, and the linear expansion coefficient is relatively large. Replacing the same amount of SEBS-g-GMA with SEBS-g-MAH does not seem to have a good toughening effect. This may be because the high-temperature resistance of maleic anhydride is limited, its reactivity decreases at high temperatures, and at the same time, the grafting rate is low, and the synergistic effect with PKHH is limited, so it cannot achieve the purpose of reducing the linear expansion coefficient.

[0058] Example 2

[0059] A preparation method of a reinforced polyphenylene sulfide composite material for a battery cover plate is as follows:

[0060] (1) Preparation of raw materials:

[0061] Polyphenylene sulfide: linear polyphenylene sulfide, with a melt index of 1000 g / 10 min at 316 °C * 5 kg, manufacturer: Chongqing Jushi New Material Technology Co., Ltd., grade: GAC08;

[0062] Compatibilizer: glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer, the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer is 2-3%, manufacturer: Jia Yirong Polymer (Shanghai) Co., Ltd., grade: SEBG-03;

[0063] Resin crosslinking agent: thermoplastic phenoxy resin, manufacturer: Union Carbide Resin PKHH of the United States, with a weight average molecular weight of 52000. The resin crosslinking agent is dissolved in cyclohexane to prepare a solution with a concentration of 20 wt%, and the viscosity measured at 25 °C is 600 mPa·s;

[0064] Glass fiber: profiled glass fiber with a non-circular cross-section, and its aspect ratio is 1:2, manufacturer: Nittobo Company of Japan, model: profiled glass fiber FF (Ratio2);

[0065] Mineral whisker: four-needle zinc oxide whisker treated with silane KH-570 coupling agent, and the diameter of each needle-like part is 0.5-5 μm, and the length is 10-50 μm;

[0066] Acid absorbent: nanolayered structure hydrotalcite, the BET surface area of the nanolayered structure hydrotalcite is greater than 10 m 2 / g, the D50 particle size is 0.2-0.5 μm, and the proportion of particles with a particle size less than 1 μm in the nanolayered structure hydrotalcite is >90%, manufacturer: Clariant, model: Hycite713;

[0067] The invention comprises, by weight, 32 parts of polyphenylene sulfide, 5 parts of a compatibilizer, 1.5 parts of a resin crosslinking agent, 21 parts of mineral whiskers, 0.5 parts of an acid absorbent and 40 parts of glass fibers;

[0068] (2) mixing polyphenylene sulfide, a compatibilizer, a resin crosslinking agent, mineral whiskers, and an acid scavenger in a high-speed mixer for 3 to 5 minutes and then discharging the mixture to obtain a mixture;

[0069] (3) The mixture obtained in step (2) is fed into the main feed port of a twin-screw extruder, and the glass fiber is fed into the side feed port of the twin-screw extruder. The processing temperature of the twin-screw extruder is controlled to be 290-320° C., and the screw speed is 180-600 rpm. Extrusion granulation is performed to obtain a reinforced polyphenylene sulfide composite material for a battery cover.

[0070] The tensile strength of the reinforced polyphenylene sulfide composite material for battery cover is 152MPa, the tensile modulus is 17200MPa, and the notched impact strength is 9.5KJ / m 2 The transverse shrinkage is 0.17%, the longitudinal shrinkage is 0.21%, and the linear expansion coefficient is 23.8*10 -6 mm / mm*℃.

[0071] Example 3

[0072] A method for preparing a reinforced polyphenylene sulfide composite material for a battery cover, comprising the following steps:

[0073] (1) Preparation of raw materials:

[0074] Polyphenylene sulfide: linear polyphenylene sulfide, melt index 1000g / 10min at 316℃*5kg, manufacturer: Chongqing Jushi New Material Technology Co., Ltd., brand: GAC08;

[0075] Compatibilizer: glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer, the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer is 2-3%, manufacturer: Jiayirong Polymer (Shanghai) Co., Ltd., brand: SEBG-03;

[0076] Resin crosslinker: thermoplastic phenoxy resin, manufacturer: Union Carbide Resin PKHH, USA, weight-average molecular weight 52,000. The resin crosslinker was dissolved in cyclohexane to prepare a 20 wt% solution. The viscosity measured at 25°C was 600 mPa·s.

[0077] Glass fiber: Shaped glass fiber with non-circular cross-section, with an aspect ratio of 1:2, manufacturer: Nittobo Co., Ltd., Japan, model: Shaped glass fiber FF (Ratio2);

[0078] Mineral whisker: Four-needle zinc oxide whisker treated with silane KH-570 coupling agent, and the diameter of each needle part is 0.5 - 5 μm, and the length is 10 - 50 μm;

[0079] Acid absorbent: Nano-layered structure hydrotalcite, the BET surface area of the nano-layered structure hydrotalcite is greater than 10 m 2 / g, the D50 particle size is 0.2 - 0.5 μm, and the proportion of particles with a particle size less than 1 μm in the nano-layered structure hydrotalcite is > 90%, manufacturer: Clariant, model: Hycite713;

[0080] By weight, it includes 30 parts of polyphenylene sulfide, 3 parts of compatibilizer, 3 parts of resin cross-linking agent, 18 parts of mineral whisker, 1 part of acid absorbent and 45 parts of glass fiber;

[0081] (2) Mix the polyphenylene sulfide, compatibilizer, resin cross-linking agent, mineral whisker and acid absorbent in a high-speed mixer for 3 - 5 min and then discharge to obtain a mixture;

[0082] (3) Feed the mixture obtained in step (2) into the main feeding port of a twin-screw extruder, and feed the glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder to be 290 - 320 °C, and the screw rotation speed to be 180 - 600 revolutions per minute, and perform extrusion granulation to obtain a reinforced polyphenylene sulfide composite material for battery covers.

[0083] The tensile strength of the finally prepared reinforced polyphenylene sulfide composite material for battery covers is 161 MPa, the tensile modulus is 18400 MPa, and the notch impact strength is 8.5 KJ / m 2 , the transverse shrinkage rate is 0.15%, the longitudinal shrinkage rate is 0.19%, and the linear expansion coefficient is 22.9 * 10 -6 mm / mm * °C.

[0084] Example 4

[0085] A preparation method of a reinforced polyphenylene sulfide composite material for battery covers, the specific steps are as follows:

[0086] (1) Preparation of raw materials:

[0087] Polyphenylene sulfide: Linear polyphenylene sulfide, the melt index at 316 °C * 5 kg is 1000 g / 10 min, manufacturer: Chongqing Jushi New Materials Technology Co., Ltd., brand: GAC08;

[0088] Compatibilizer: Glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer, the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer is 2-3%, manufacturer: Jia Yirong Polymer (Shanghai) Co., Ltd., grade: SEBG-03;

[0089] Resin crosslinking agent: Thermoplastic phenoxy resin, manufacturer: Union Carbide Resin PKHH, USA, the weight average molecular weight is 52000, dissolve the resin crosslinking agent in cyclohexane to prepare a solution with a concentration of 20wt%, and the viscosity measured at 25°C is 600mPa.s;

[0090] Glass fiber: Special-shaped glass fiber with a non-circular cross-section, the aspect ratio of length to width is 1:2, manufacturer: Nittobo Co., Ltd., Japan, model: Special-shaped glass fiber FF (Ratio2);

[0091] Mineral whisker: Four-needle zinc oxide whisker treated with silane KH-570 coupling agent, and the diameter of each needle part is 0.5-5μm, and the length is 10-50μm;

[0092] Acid absorbent: Nano-layered structure hydrotalcite, the BET surface area of the nano-layered structure hydrotalcite is greater than 10m 2 / g, the D50 particle size is 0.2-0.5μm, and the proportion of particles with a particle size less than 1μm in the nano-layered structure hydrotalcite is >90%, manufacturer: Clariant, model: Hycite713;

[0093] By weight, it includes 30.8 parts of polyphenylene sulfide, 4 parts of compatibilizer, 2 parts of resin crosslinking agent, 12 parts of mineral whisker, 1.2 parts of acid absorbent and 50 parts of glass fiber;

[0094] (2) Mix polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent in a high-speed mixer for 3-5 minutes and then discharge to obtain a mixture;

[0095] (3) Feed the mixture obtained in step (2) into the main feeding port of the twin-screw extruder, and feed the glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder to be 290-320°C, and the screw rotation speed to be 180-600 revolutions per minute, and perform extrusion granulation to obtain the reinforced polyphenylene sulfide composite material for battery cover.

[0096] The tensile strength of the finally prepared reinforced polyphenylene sulfide composite material for battery cover is 172MPa, the tensile modulus is 19500MPa, and the notch impact strength is 9.7KJ / m 2 , the transverse shrinkage rate is 0.13%, the longitudinal shrinkage rate is 0.18%, and the linear expansion coefficient is 22.8*10 -6 mm / mm*°C.

[0097] Example 5

[0098] A preparation method of a reinforced polyphenylene sulfide composite material for a battery cover plate, the specific steps are as follows:

[0099] (1) Preparation of raw materials:

[0100] Polyphenylene sulfide: linear polyphenylene sulfide, the melt index at 316 °C * 5 kg is 1000 g / 10 min, manufacturer: Chongqing Jushi New Material Technology Co., Ltd., grade: GAC08;

[0101] Compatibilizer: glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer, the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butene-styrene copolymer is 2-3%, manufacturer: Jia Yirong Polymer (Shanghai) Co., Ltd., grade: SEBG-03;

[0102] Resin crosslinking agent: thermoplastic phenoxy resin, manufacturer: Union Carbide Resin PKHH, USA, the weight average molecular weight is 52000, the resin crosslinking agent is dissolved in cyclohexane to prepare a solution with a concentration of 20 wt%, and the viscosity measured at 25 °C is 600 mPa.s;

[0103] Glass fiber: profiled glass fiber with a non-circular cross-section, the aspect ratio of length to width is 1:2, manufacturer: Nittobo Co., Ltd., Japan, model: profiled glass fiber FF (Ratio2);

[0104] Mineral whisker: four-needle zinc oxide whisker treated with silane KH-570 coupling agent, and the diameter of each needle part is 0.5-5 μm, and the length is 10-50 μm;

[0105] Acid absorbent: nanolayered structure hydrotalcite, the BET surface area of the nanolayered structure hydrotalcite is greater than 10 m 2 / g, the D50 particle size is 0.2-0.5 μm, and the proportion of particles with a particle size less than 1 μm in the nanolayered structure hydrotalcite is >90%, manufacturer: Clariant, model: Hycite713;

[0106] By weight, it includes 29.5 parts of polyphenylene sulfide, 2 parts of compatibilizer, 1 part of resin crosslinking agent, 16 parts of mineral whisker, 0.5 part of acid absorbent and 50 parts of glass fiber;

[0107] (2) Mix the polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent in a high-speed mixer for 3-5 minutes and then discharge to obtain a mixture;

[0108] (3) Feed the mixture obtained in step (2) into the main feeding port of the twin-screw extruder, and feed the glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder to be 290 - 320 °C and the screw rotation speed to be 180 - 600 revolutions per minute, and perform extrusion granulation to obtain the reinforced polyphenylene sulfide composite material for battery covers.

[0109] The tensile strength of the finally obtained reinforced polyphenylene sulfide composite material for battery covers is 178 MPa, the tensile modulus is 20200 MPa, and the notch impact strength is 8.8 KJ / m 2 , the transverse shrinkage rate is 0.11%, the longitudinal shrinkage rate is 0.16%, and the linear expansion coefficient is 22.1×10 -6 mm / mm·°C.

Claims

1. An enhanced polyphenylene sulfide composite material for a battery cover plate, characterized in that Comprising the following components in parts by weight: The compatibilizer is glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer; the grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted styrene-ethylene / butylene-styrene copolymer is 2-3%; The resin crosslinking agent is a thermoplastic phenoxy resin; The acid absorbent is a nanolayered structure hydrotalcite.

2. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 1, wherein, The resin crosslinking agent is dissolved in cyclohexane to prepare a solution with a concentration of 20 wt%, the viscosity measured at 25 °C is 500-750 mPa·s, and the weight average molecular weight is 30,000-60,000.

3. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 1, wherein, The BET surface area of the nano-layered structure hydrotalcite is greater than 10 m 2 / g, the D50 particle size is 0.2 - 0.5 μm, and the proportion of particles with a particle size less than 1 μm in the nano-layered structure hydrotalcite is > 90%.

4. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 1, characterized in that, The polyphenylene sulfide is a linear polyphenylene sulfide, and the melt index under the conditions of 316 °C * 5 kg is 600-1500 g / 10 min.

5. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 1, wherein The glass fiber is a special-shaped glass fiber with a non-circular cross-section, and its aspect ratio is 1:

2.

6. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 1, wherein The mineral whisker is one or more of zinc oxide whisker, magnesium borate whisker, calcium sulfate whisker, magnesium sulfate whisker and potassium titanate whisker; the surface of the mineral whisker is treated with a silane KH-570 coupling agent.

7. The reinforced polyphenylene sulfide composite material for a battery cover plate according to claim 6, characterized in that, The zinc oxide whisker is a tetrapod whisker, and the diameter of each needle-like part is 0.5-5 μm, and the length is 10-50 μm.

8. The preparation method of a reinforced polyphenylene sulfide composite material for a battery cover plate according to any one of claims 1 to 7, characterized in that Comprising the following steps: (1) Mix polyphenylene sulfide, compatibilizer, resin crosslinking agent, mineral whisker and acid absorbent in a high-speed mixer for 3-5 min and then discharge to obtain a mixture; (2) Feed the mixture obtained in step (1) into the main feeding port of a twin-screw extruder, and feed the glass fiber into the side feeding port of the twin-screw extruder. Control the processing temperature of the twin-screw extruder to be 290-320 °C, and the screw rotation speed to be 180-600 revolutions per minute, and perform extrusion granulation to obtain the reinforced polyphenylene sulfide composite material for the battery cover plate.

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