A ceramic PC film flame retardant material for power batteries and its preparation method

Abstract

The present invention relates to the field of flame retardant technology of diaphragms for power batteries, and specifically to a ceramic PC film flame retardant material dedicated to power batteries and a preparation method thereof. First, polycarbonate particles are blended and modified with a silane coupling agent to improve the surface polarity of the polycarbonate particles, providing a guarantee for the subsequent addition of inorganic substances to be better dispersed in the system; polycarbonate powder is mixed with nano-aluminum nitride, and the powders are blended in the form of powders, which is conducive to better dispersion of nano-aluminum nitride, significantly improving the thermal conductivity of PC, and its heat dissipation performance can also be greatly improved. After the PC is ceramicized and modified, its thermal deformation is improved, its heat resistance is improved, and its flame retardant performance is enhanced, reaching 0.5mm UL94V0 level; the present invention just makes up for the lack of heat resistance or fire resistance of the current battery plate diaphragm, and improves the heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardant membranes of power batteries, and in particular to a ceramic PC film flame retardant material dedicated to power batteries and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the requirements for the safety, performance and life of power batteries are also increasing. Among them, the battery separator is a key component of the power battery, and its performance directly affects the overall performance of the battery. At present, the main separator materials used in the market are polyolefin materials, but they have poor thermal stability and are easy to melt at high temperatures, causing battery short circuits. Therefore, the development of a separator material with excellent thermal stability has become a hot topic in current research.

[0003] In order to solve the above problems, most of the existing technologies use a slurry containing inorganic ceramic particles and flame retardants to coat the PE or PP diaphragm, so that the diaphragm has high heat resistance and improved flame retardancy. However, there is a risk of the coating falling off and separating after a period of use, and it is difficult to continue to play a role. If inorganic ceramic particles are compounded with a polymer matrix, the dispersion of the inorganic ceramic particles is poor during the preparation process, which can easily lead to uneven diaphragm performance and poor flame retardancy, heat dissipation and stability. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, one of the purposes of the present invention is to provide a method for preparing a ceramicized PC film flame retardant material dedicated to power batteries. After the PC is ceramicized and modified, its thermal deformation is improved, and its heat resistance is improved; after ceramicization, its flame retardant performance is enhanced, reaching 0.5mm UL94 V0 level; at the same time, the nano-level aluminum nitride evenly dispersed in the material has an ultra-high specific surface area, which significantly improves the thermal conductivity of PC, and its heat dissipation performance can also be greatly improved. The present invention just makes up for the lack of heat resistance or fire resistance of the current battery plate diaphragm, and improves the heat dissipation performance. The preparation method is simple to operate, easy to control, high in production efficiency, low in production cost, and can be used for large-scale production.

[0005] A second object of the present invention is to provide a ceramic PC film flame retardant material dedicated to power batteries.

[0006] One of the purposes of the present invention is achieved by the following technical solution: A method for preparing a ceramic PC film flame retardant material dedicated to a power battery, comprising the following steps:

[0007] (S1), taking polycarbonate particles, heating and stirring at a speed of 1200-1600 r / min for 5-8 min, adding a silane coupling agent when the material temperature reaches 78-83° C., and then stirring at a speed of 800-1200 r / min for 3-5 min to obtain modified polycarbonate particles;

[0008] (S2), taking polycarbonate powder, adding nano-aluminum nitride, stirring at a speed of 1200-1600 r / min for 15-18 min to obtain a powder blend;

[0009] (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid, an anti-dripping agent, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 800-1200 r / min for 3-5 min to obtain a PC blend material;

[0010] (S4), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a ceramicized PC film flame retardant material.

[0011] The preparation method of the ceramicized PC film flame retardant material comprises the following steps: firstly, polycarbonate particles are blended and modified with a silane coupling agent to improve the surface polarity of the polycarbonate particles, thereby providing a guarantee for the subsequent addition of inorganic substances to be better dispersed in the system; secondly, polycarbonate powder is mixed with nano-aluminum nitride, and the powders are blended in the form of powders, which is conducive to better dispersion of the nano-aluminum nitride. Meanwhile, the nano-scale aluminum nitride uniformly dispersed in the material has an ultra-high specific surface area, which significantly improves the thermal conductivity of the PC, and its heat dissipation performance can also be greatly improved; the powder blend is added to the modified polycarbonate particles, and the polycarbonate particles, There is also polycarbonate powder. Due to its fine particle size and high specific surface area, powder materials often have high surface energy and mutual attraction, which easily leads to agglomeration, caking or adhesion to the container wall during the mixing process, which is not conducive to material feeding; in addition, nanomaterials in the system are more likely to agglomerate due to their extremely small size, which further increases the difficulty of material feeding. In order to solve this problem, polycarbonate particles have a larger particle size and lower surface energy, which can play a role in dispersion and lubrication in powder materials, reduce direct contact and interaction between powder materials, and thus reduce the possibility of agglomeration and caking. At the same time, the addition of polycarbonate particles can also improve the fluidity of the material, making it easier to discharge from the mixing container and improving the efficiency of material feeding. The added processing aid can effectively improve the melt tension, improve the mold expansion, and improve the dispersion of the filler, which is more conducive to the film drawing and forming of the ceramicized PC film flame retardant material during the film making process; the added composite flame retardant and anti-dripping agent have a good flame retardant and flame resistant effect, especially when mixed with the ceramicized flame retardant, the flame retardant performance of the flame retardant material is enhanced after ceramicization, and the flame retardant carbon layer covers the ceramic layer during the combustion process, and the flame retardant effect can reach 0.5mm UL94 V0 level; the added thermal conductive filler further improves the thermal conductivity of the PC material and improves the heat dissipation effect; the added inorganic ceramic filler improves the thermal deformation and heat resistance of the PC after the PC is ceramicized, and under the action of the ceramicized flame retardant, it begins to melt at about 900°C to form a ceramic state, which is conducive to reducing the ceramicization problem of the inorganic filler and improving the ceramicization degree of PC during the combustion process; the added special toughening agent is conducive to reinforcing the toughness of the material, and the special toughening agent has its own flame retardancy, which avoids the impact of the toughening agent on the flame retardant performance.

[0012] Preferably, the weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 30-70 parts of polycarbonate particles, 0.1-0.5 parts of silane coupling agent, 15-25 parts of polycarbonate powder, 1-10 parts of nano-aluminum nitride, 0.1-1 parts of processing aid, 0.1-0.5 parts of anti-dripping agent, 3-23 parts of composite flame retardant, 1-10 parts of thermal conductive filler, 2-20 parts of inorganic ceramic filler and 0.5-3 parts of toughening agent.

[0013] Preferably, the polycarbonate particles are selected from models L-1250Y and / or 3025IR, the polycarbonate powder is selected from models L-1250WP and / or FN1900; and the silane coupling agent is selected from at least one of models KH550, KH560 and KH570.

[0014] By adopting the above technical solution, the polycarbonate particles and polycarbonate powder themselves have excellent thermal stability and mechanical properties, which is more conducive to ensuring the thermal stability of the flame retardant material.

[0015] Preferably, the processing aid is selected from model A-3000; the anti-drip agent is selected from model K-PT107 and / or K-PT200.

[0016] By adopting the above technical solution, the processing aid A-3000 can effectively increase the melt tension, improve the mold expansion, and improve the dispersion of the filler, which is more conducive to the film drawing and film formation of the ceramic PC film flame retardant material during the film making process.

[0017] Preferably, the composite flame retardant is compounded by a ceramic flame retardant, a sulfonate flame retardant and a silicone flame retardant in a weight ratio of 1-10:1-3:1-10.

[0018] With the above technical solution, the ceramic flame retardant mainly plays the role of ceramicization, and also plays the role of assisting flame retardancy. It promotes the formation of a dense ceramic protective layer on the surface of PC during the combustion process, thereby significantly improving the flame retardancy and ceramicization degree of PC, which can effectively isolate heat and oxygen and prevent the further spread of flames. It mainly acts between the interior of the material and the carbon layer, and can reduce the ceramicization problem of inorganic fillers and improve the ceramicization degree of PC during the combustion process. Sulfonate is the main flame retardant, which can accelerate the carbonization of PC materials. During the combustion process, it migrates to the surface of the material and forms a carbon layer on the surface of the PC material, which plays a barrier role. Silicone flame retardant can also accelerate the carbonization of PC materials, forming a carbon layer on the surface of PC materials, and at the same time, non-combustible SiO2 particles are formed during the combustion process, making the flame retardant barrier more dense. The ceramic flame retardant, sulfonate flame retardant and silicone flame retardant work synergistically, and the flame retardant carbon layer covers the ceramic layer. After the flame retardant material is ceramicized, its flame retardant performance is enhanced to reach 0.5MM UL94V0 level.

[0019] More preferably, the ceramic flame retardant is selected from model ZB03-500 and / or AFirebrake ZB; the sulfonate flame retardant is selected from model KFR-KKS-A2; and the silicone flame retardant is selected from at least one of model SIFR-SI907, FCA-107 and Dow Corning 40-001.

[0020] Preferably, the thermally conductive filler is at least one of aluminum oxide, magnesium oxide, zinc oxide and boron nitride; the inorganic ceramic filler is ultrafine talc and kaolin; and the toughening agent is selected from model MR01 / USI-3309.

[0021] By adopting the above technical solution, the added thermal conductive filler further improves the thermal conductivity of the PC material and improves the heat dissipation effect; the added inorganic ceramic filler realizes the PC ceramic modification, and its thermal deformation is improved, and its heat resistance is improved. Under the action of the ceramic flame retardant, it begins to melt and form a ceramic state at about 900°C, which is conducive to reducing the ceramicization problem of inorganic filling and improving the ceramicization degree of PC during the combustion process; more preferably, the inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 1-10:1-10, the mesh number of the ultrafine talcum powder is 8000-10000 mesh, and the mesh number of the kaolin is 8000-10000 mesh. The addition of the above special toughening agent is conducive to strengthening the toughness of the material, and the above special toughening agent has its own flame retardancy, avoiding the impact of the addition of the toughening agent on the flame retardancy.

[0022] Preferably, in the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone one is controlled at 230-240°C, the temperature of zone two is controlled at 260-270°C, the temperature of zone three is controlled at 270-280°C, the temperature of zone four is controlled at 270-280°C, the temperature of zone five is controlled at 260-270°C, the temperature of zone six is ​​controlled at 260-270°C, the temperature of zone seven is controlled at 260-270°C, the temperature of zone eight is controlled at 260-270°C, the temperature of zone nine is controlled at 270-280°C, the temperature of zone ten is controlled at 270-280°C, the head temperature is controlled at 280-285°C, the screw speed is 300-500r / min, the feeding speed is set at 13-18HZ, and the total residence time is controlled at 2-3min.

[0023] Preferably, the method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps:

[0024] (R1), take the ceramic PC film flame retardant material and dry it at a temperature of 115-125°C for 3-5 hours;

[0025] (R2) The ceramic PC film flame retardant material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 260-270°C, the temperature of screw zone B is controlled at 260-270°C, the temperature of screw zone C is controlled at 270-280°C, and the temperature of the head is controlled at 280-285°C; the main engine speed is controlled at 50-60HZ, the traction speed 1 is set to 8-10m / min, the traction speed 2 is set to 8-10m / min, the traction speed 3 is set to 10-12m / min, the traction speed 4 is set to 10-12m / min, the winding speed is set to 14-16m / min, the film temperature of the roller is set to 98-105°C, the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.4-0.5mm.

[0026] Preferably, the particle size of the nano-aluminum nitride is 50-100 nm.

[0027] The second object of the present invention is achieved through the following technical solution: A ceramic PC film flame retardant material dedicated to power batteries is prepared by the above-mentioned preparation method of the ceramic PC film flame retardant material dedicated to power batteries.

[0028] The beneficial effects of the present invention are as follows: the preparation method of the ceramicized PC film flame retardant material for power batteries of the present invention improves the thermal deformation and heat resistance of PC after ceramicization modification; after ceramicization, its flame retardant performance is enhanced to reach 0.5mm UL94 V0 level; at the same time, the nano-scale aluminum nitride evenly dispersed in the material has an ultra-high specific surface area, which significantly improves the thermal conductivity of PC, and its heat dissipation performance can also be greatly improved. The present invention just makes up for the lack of heat resistance or fireproof performance of the current battery plate diaphragm, and improves the heat dissipation performance. The preparation method is simple to operate, easy to control, high in production efficiency, low in production cost, and can be used for large-scale production.

[0029] The ceramic PC film flame retardant material dedicated to power batteries of the present invention has significantly improved thermal stability, heat dissipation and flame retardancy, and is particularly suitable for making battery plate diaphragms, making up for the defects of insufficient heat resistance, heat dissipation or fire resistance of current battery plate diaphragms. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0031] Example 1

[0032] A method for preparing a ceramic PC film flame retardant material dedicated to a power battery comprises the following steps:

[0033] (S1), taking polycarbonate particles L-1250Y, heating and stirring at a speed of 1500 r / min for 6 minutes, adding silane coupling agent KH560 when the material temperature reaches 80°C, and stirring at a speed of 1000 r / min for 4 minutes to obtain modified polycarbonate particles;

[0034] (S2), taking polycarbonate powder L-1250WP, adding nano-aluminum nitride, and stirring at a speed of 1500 r / min for 16 min to obtain a powder blend;

[0035] (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid A-3000, an anti-dripping agent K-PT107, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 1000 r / min for 4 min to obtain a PC blend material;

[0036] (S4), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a ceramicized PC film flame retardant material.

[0037] The weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 50.2 parts of polycarbonate particles, 0.5 parts of silane coupling agent, 20 parts of polycarbonate powder, 4 parts of nano-aluminum nitride, 0.5 parts of processing aid, 0.3 parts of anti-dripping agent, 9 parts of composite flame retardant, 4 parts of thermal conductive filler, 10 parts of inorganic ceramic filler and 1.5 parts of toughening agent.

[0038] The composite flame retardant is prepared by compounding a ceramic flame retardant, a sulfonate flame retardant and an organosilicon flame retardant in a weight ratio of 3:1:5.

[0039] The ceramic flame retardant is selected from the model ZB03-500; the sulfonate flame retardant is selected from the model KFR-KKS-A2; and the silicone flame retardant is selected from the model SIFR-SI907.

[0040] The thermal conductive filler is alumina; the inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 5:5, the mesh number of the ultrafine talcum powder is 10000 mesh, and the mesh number of the kaolin is 8000 mesh; the toughening agent is selected from model MR01.

[0041] The particle size of the nano aluminum nitride is 70 nm.

[0042] In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 235°C, the temperature of zone 2 is controlled at 265°C, the temperature of zone 3 is controlled at 275°C, the temperature of zone 4 is controlled at 275°C, the temperature of zone 5 is controlled at 265°C, the temperature of zone 6 is controlled at 265°C, the temperature of zone 7 is controlled at 265°C, the temperature of zone 8 is controlled at 265°C, the temperature of zone 9 is controlled at 275°C, the temperature of zone 10 is controlled at 275°C, the head temperature is controlled at 283°C, the screw speed is 400r / min, the feeding speed is set to 15HZ, and the total residence time is controlled at 2min.

[0043] The method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps:

[0044] (R1), take the ceramicized PC film flame retardant material and dry it at 120°C for 4 hours;

[0045] (R2) The ceramic PC flame retardant film material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 265°C, the temperature of screw zone B is controlled at 265°C, the temperature of screw zone C is controlled at 275°C, and the temperature of the head is controlled at 283°C; the main engine speed is controlled at 55HZ, the traction speed 1 is set to 9m / min, the traction speed 2 is set to 9m / min, the traction speed 3 is set to 11m / min, the traction speed 4 is set to 11m / min, the winding speed is set to 15m / min, the film temperature of the roller is set to 100°C, and the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.5mm.

[0046] Example 2

[0047] A method for preparing a ceramic PC film flame retardant material dedicated to a power battery comprises the following steps:

[0048] (S1), taking polycarbonate particles L-1250Y, heating and stirring at a speed of 1500 r / min for 5 min, adding silane coupling agent KH560 when the material temperature reaches 80°C, and stirring at a speed of 1000 r / min for 3 min to obtain modified polycarbonate particles;

[0049] (S2), taking polycarbonate powder L-1250WP, adding nano-aluminum nitride, stirring at a speed of 1500 r / min for 15 min to obtain a powder blend;

[0050] (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid A-3000, an anti-dripping agent K-PT107, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 1000 r / min for 3 min to obtain a PC blend material;

[0051] (S4), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a ceramicized PC film flame retardant material.

[0052] The weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 52.7 parts of polycarbonate particles, 0.3 parts of silane coupling agent, 20 parts of polycarbonate powder, 2 parts of nano-aluminum nitride, 0.5 parts of processing aid, 0.5 parts of anti-dripping agent, 5 parts of composite flame retardant, 5 parts of thermal conductive filler, 13 parts of inorganic ceramic filler and 0.8 parts of toughening agent.

[0053] The composite flame retardant is prepared by compounding a ceramic flame retardant, a sulfonate flame retardant and an organosilicon flame retardant in a weight ratio of 1:1:3.

[0054] The ceramic flame retardant is selected from the model AFirebrake ZB; the sulfonate flame retardant is selected from the model KFR-KKS-A2; and the organosilicon flame retardant is selected from the model FCA-107.

[0055] The thermal conductive filler is alumina; the inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 10:3, the mesh number of the ultrafine talcum powder is 8000 mesh, and the mesh number of the kaolin is 8000 mesh; the toughening agent is selected from model MR01.

[0056] The particle size of the nano aluminum nitride is 100 nm.

[0057] In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 230°C, the temperature of zone 2 is controlled at 260°C, the temperature of zone 3 is controlled at 270°C, the temperature of zone 4 is controlled at 270°C, the temperature of zone 5 is controlled at 270°C, the temperature of zone 6 is controlled at 260°C, the temperature of zone 7 is controlled at 270°C, the temperature of zone 8 is controlled at 260°C, the temperature of zone 9 is controlled at 280°C, the temperature of zone 10 is controlled at 280°C, the head temperature is controlled at 280°C, the screw speed is 300r / min, the feeding speed is set to 13HZ, and the total residence time is controlled at 2min.

[0058] The method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps:

[0059] (R1), take the ceramicized PC film flame retardant material and dry it at 120°C for 4 hours;

[0060] (R2) The ceramic PC flame retardant film material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 260°C, the temperature of screw zone B is controlled at 260°C, the temperature of screw zone C is controlled at 270°C, and the temperature of the head is controlled at 280°C; the main engine speed is controlled at 50HZ, the traction speed 1 is set to 8m / min, the traction speed 2 is set to 8m / min, the traction speed 3 is set to 10m / min, the traction speed 4 is set to 10m / min, the winding speed is set to 14m / min, the film temperature of the roller is set at 100°C, and the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.5mm.

[0061] Example 3

[0062] A method for preparing a ceramic PC film flame retardant material dedicated to a power battery comprises the following steps:

[0063] (S1), taking polycarbonate particles L-1250Y, heating and stirring at a speed of 1500 r / min for 8 minutes, adding silane coupling agent KH560 when the material temperature reaches 80°C, and stirring at a speed of 1000 r / min for 5 minutes to obtain modified polycarbonate particles;

[0064] (S2), taking polycarbonate powder L-1250WP, adding nano-aluminum nitride, stirring at a speed of 1500 r / min for 18 min to obtain a powder blend;

[0065] (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid A-3000, an anti-dripping agent K-PT107, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 1000 r / min for 5 minutes to obtain a PC blend material;

[0066] (S4), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a ceramicized PC film flame retardant material.

[0067] The weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 42.7 parts of polycarbonate particles, 0.5 parts of silane coupling agent, 20 parts of polycarbonate powder, 7 parts of nano-aluminum nitride, 0.5 parts of processing aid, 0.5 parts of anti-dripping agent, 15 parts of composite flame retardant, 2 parts of thermal conductive filler, 13 parts of inorganic ceramic filler and 3 parts of toughening agent.

[0068] The composite flame retardant is prepared by compounding a ceramic flame retardant, a sulfonate flame retardant and an organosilicon flame retardant in a weight ratio of 7:1:7.

[0069] The ceramic flame retardant is selected from the model ZB03-500; the sulfonate flame retardant is selected from the model KFR-KKS-A2; and the silicone flame retardant is selected from the model SIFR-SI907.

[0070] The thermal conductive filler is alumina; the inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 3:10, the mesh number of the ultrafine talcum powder is 10000 mesh, and the mesh number of the kaolin is 10000 mesh; the toughening agent is selected from model MR01.

[0071] The particle size of the nano aluminum nitride is 50 nm.

[0072] In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 240°C, the temperature of zone 2 is controlled at 270°C, the temperature of zone 3 is controlled at 270°C, the temperature of zone 4 is controlled at 280°C, the temperature of zone 5 is controlled at 270°C, the temperature of zone 6 is controlled at 260°C, the temperature of zone 7 is controlled at 270°C, the temperature of zone 8 is controlled at 260°C, the temperature of zone 9 is controlled at 270°C, the temperature of zone 10 is controlled at 280°C, the head temperature is controlled at 285°C, the screw speed is 500r / min, the feeding speed is set to 18HZ, and the total residence time is controlled at 3min.

[0073] The method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps:

[0074] (R1), take the ceramicized PC film flame retardant material and dry it at 120°C for 4 hours;

[0075] (R2) The ceramic PC film flame retardant material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 270°C, the temperature of screw zone B is controlled at 270°C, the temperature of screw zone C is controlled at 280°C, and the temperature of the head is controlled at 285°C; the main engine speed is controlled at 60HZ, the traction speed 1 is set to 10m / min, the traction speed 2 is set to 10m / min, the traction speed 3 is set to 12m / min, the traction speed 4 is set to 12m / min, the winding speed is set to 16m / min, the film temperature of the roller is set to 100°C, the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.5mm.

[0076] Example 4

[0077] A method for preparing a ceramic PC film flame retardant material dedicated to a power battery comprises the following steps:

[0078] (S1), taking polycarbonate particles L-1250Y, heating and stirring at a speed of 1500 r / min for 7 minutes, adding silane coupling agent KH560 when the material temperature reaches 80°C, and stirring at a speed of 1000 r / min for 5 minutes to obtain modified polycarbonate particles;

[0079] (S2), taking polycarbonate powder L-1250WP, adding nano-aluminum nitride, stirring at a speed of 1500 r / min for 18 min to obtain a powder blend;

[0080] (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid A-3000, an anti-dripping agent K-PT107, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 1000 r / min for 5 minutes to obtain a PC blend material;

[0081] (S4), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a ceramicized PC film flame retardant material.

[0082] The weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 60 parts of polycarbonate particles, 0.3 parts of silane coupling agent, 16 parts of polycarbonate powder, 6 parts of nano-aluminum nitride, 0.6 parts of processing aid, 0.3 parts of anti-dripping agent, 18 parts of composite flame retardant, 2 parts of thermal conductive filler, 10 parts of inorganic ceramic filler and 1 part of toughening agent.

[0083] The composite flame retardant is prepared by compounding a ceramic flame retardant, a sulfonate flame retardant and an organosilicon flame retardant in a weight ratio of 4:2:4.

[0084] The ceramic flame retardant is selected from the model ZB03-500; the sulfonate flame retardant is selected from the model KFR-KKS-A2; and the silicone flame retardant is selected from the model SIFR-SI907.

[0085] The thermal conductive filler is alumina; the inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 5:5, the mesh number of the ultrafine talcum powder is 8000 mesh, and the mesh number of the kaolin is 10000 mesh; the toughening agent is selected from model MR01.

[0086] The particle size of the nano aluminum nitride is 60 nm.

[0087] In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 235°C, the temperature of zone 2 is controlled at 265°C, the temperature of zone 3 is controlled at 275°C, the temperature of zone 4 is controlled at 275°C, the temperature of zone 5 is controlled at 265°C, the temperature of zone 6 is controlled at 265°C, the temperature of zone 7 is controlled at 265°C, the temperature of zone 8 is controlled at 265°C, the temperature of zone 9 is controlled at 275°C, the temperature of zone 10 is controlled at 275°C, the head temperature is controlled at 283°C, the screw speed is 400r / min, the feeding speed is set to 15HZ, and the total residence time is controlled at 2min.

[0088] The method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps:

[0089] (R1), take the ceramicized PC film flame retardant material and dry it at 120°C for 4 hours;

[0090] (R2) The ceramic PC flame retardant film material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 265°C, the temperature of screw zone B is controlled at 265°C, the temperature of screw zone C is controlled at 275°C, and the temperature of the head is controlled at 283°C; the main engine speed is controlled at 55HZ, the traction speed 1 is set to 9m / min, the traction speed 2 is set to 9m / min, the traction speed 3 is set to 11m / min, the traction speed 4 is set to 11m / min, the winding speed is set to 15m / min, the film temperature of the roller is set to 100°C, and the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.5mm.

[0091] Comparative Example 1

[0092] A method for preparing a PC film flame retardant material comprises the following steps:

[0093] (S1), taking polycarbonate particles L-1250Y, heating and stirring at a speed of 1500 r / min for 6 minutes, adding silane coupling agent KH560 when the material temperature reaches 80°C, and stirring at a speed of 1000 r / min for 4 minutes to obtain modified polycarbonate particles;

[0094] (S2), adding polycarbonate powder L-1250WP to the modified polycarbonate particles, and then adding processing aid A-3000, anti-dripping agent K-PT107 and composite flame retardant, stirring at a speed of 1000 r / min for 4 minutes to obtain a PC blend material;

[0095] (S3), melt-extrude the PC blended material through a twin-screw extruder and granulate to obtain a PC film flame retardant material.

[0096] The weight amounts of the components of the ceramicized PC film flame retardant material are as follows: 59.7 parts of polycarbonate particles, 0.5 parts of silane coupling agent, 20 parts of polycarbonate powder, 0.5 parts of processing aid, 0.3 parts of anti-dripping agent, 10 parts of inorganic ceramic filler and 9 parts of composite flame retardant.

[0097] The composite flame retardant is prepared by compounding sulfonate flame retardant FR-2025 and sulfonate flame retardant KSS-103 in a weight ratio of 1:8.

[0098] The inorganic ceramic filler is a mixture of ultrafine talcum powder and kaolin in a weight ratio of 5:5; the mesh number of the ultrafine talcum powder is 8000 mesh, and the mesh number of the kaolin is 10000 mesh.

[0099] In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 235°C, the temperature of zone 2 is controlled at 265°C, the temperature of zone 3 is controlled at 275°C, the temperature of zone 4 is controlled at 275°C, the temperature of zone 5 is controlled at 265°C, the temperature of zone 6 is controlled at 265°C, the temperature of zone 7 is controlled at 265°C, the temperature of zone 8 is controlled at 265°C, the temperature of zone 9 is controlled at 275°C, the temperature of zone 10 is controlled at 275°C, the head temperature is controlled at 283°C, the screw speed is 400r / min, the feeding speed is set to 15HZ, and the total residence time is controlled at 2min.

[0100] The method for preparing PC film from the PC film flame retardant material comprises the following steps:

[0101] (R1), take the PC film flame retardant material and dry it at 120°C for 4 hours;

[0102] (R2) PC film flame retardant material is made into film by cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 265°C, the temperature of screw zone B is controlled at 265°C, the temperature of screw zone C is controlled at 275°C, and the temperature of the head is controlled at 283°C; the main engine speed is controlled at 55HZ, the traction speed 1 is set to 9m / min, the traction speed 2 is set to 9m / min, the traction speed 3 is set to 11m / min, the traction speed 4 is set to 11m / min, the winding speed is set to 15m / min, the film temperature of the roller is set to 100°C, the film drawing operation is carried out, and the distance between the two rollers is adjusted to obtain a PC film with a thickness of 0.5mm.

[0103] Comparative Example 2

[0104] The difference between this comparative example and Example 1 is:

[0105] The composite flame retardant is prepared by compounding brominated triazine flame retardant FR-245 and antimony trioxide in a weight ratio of 3:1.

[0106] Comparative Example 3

[0107] The difference between this comparative example and Example 1 is:

[0108] The inorganic ceramic filler is replaced with 1000 mesh asbestos powder.

[0109] Performance Testing

[0110] The PC films of Examples 1-4 and Comparative Examples 1-3 were tested for flame retardancy; the flame retardant materials of Examples 1-4 and Comparative Examples 1-3 were tested for thermal deformation, thermal conductivity, Izod impact strength, tensile properties and bending properties; the test methods are as follows:

[0111] According to the UL94 standard, the flame retardant test of 0.5mm thick PC film was carried out;

[0112] According to the standard of GB / T 1634.1-2019, samples of flame retardant materials are prepared and thermal deformation tests are carried out;

[0113] According to the standard of GBT3139-2005, the flame retardant materials are sampled and the thermal conductivity is tested;

[0114] According to the standard of GB / T 1843-2008, the flame retardant material samples were prepared and the cantilever beam impact strength test was carried out;

[0115] According to the standard of GB / T 1040.2-2022, the flame retardant materials are sampled and the tensile properties are tested;

[0116] According to the standard of GB / T 9341-2008, samples of flame retardant materials were prepared and the bending performance test was carried out.

[0117] The test results are shown in Table 1 below:

[0118]

[0119] As shown in Table 1 above, the ceramicized PC film flame retardant material prepared by the preparation method of the present invention has improved thermal deformation and heat resistance after PC ceramic modification; its flame retardant performance is enhanced after ceramic modification, reaching 0.5mm UL94 V0 level; at the same time, the nano-level aluminum nitride evenly dispersed in the material has an ultra-high specific surface area, which significantly improves the thermal conductivity of PC, and its heat dissipation performance can also be greatly improved. The present invention just makes up for the lack of heat resistance or fire resistance of the current battery plate diaphragm, and improves the heat dissipation performance.

[0120] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A method for preparing a ceramic PC film flame retardant material for power batteries, characterized in that: The steps include: (S1), taking polycarbonate particles, heating and stirring at a speed of 1200-1600 r / min for 5-8 min, adding a silane coupling agent when the material temperature reaches 78-83° C., and then stirring at a speed of 800-1200 r / min for 3-5 min to obtain modified polycarbonate particles; (S2), taking polycarbonate powder, adding nano-aluminum nitride, stirring at a speed of 1200-1600 r / min for 15-18 min to obtain a powder blend; (S3), adding the powder blend to the modified polycarbonate particles, and then adding a processing aid, an anti-dripping agent, a composite flame retardant, a thermal conductive filler, an inorganic ceramic filler and a toughening agent, and stirring at a speed of 800-1200 r / min for 3-5 min to obtain a PC blend material; (S4), melt-extrude and granulate the PC blended material through a twin-screw extruder to obtain a ceramicized PC film flame retardant material; The composite flame retardant is prepared by mixing a ceramic flame retardant, a sulfonate flame retardant and an organosilicon flame retardant in a weight ratio of 1-10:1-3:1-10; The ceramic flame retardant is selected from the model ZB03-500 and / or AFirebrake ZB; the sulfonate flame retardant is selected from the model KFR-KKS-A2; the silicone flame retardant is selected from at least one of the models SIFR-SI907, FCA-107 and Dow Corning 40-001; The thermal conductive filler is at least one of aluminum oxide, magnesium oxide, zinc oxide and boron nitride; the inorganic ceramic filler is ultrafine talc and kaolin; and the toughening agent is selected from model MR01 / USI-3309.

2. The method for preparing a ceramic PC film flame retardant material for power batteries according to claim 1, characterized in that: The weight proportions of the components of the ceramicized PC film flame retardant material are as follows: 30-70 parts of polycarbonate particles, 0.1-0.5 parts of silane coupling agents, 15-25 parts of polycarbonate powders, 1-10 parts of nano-aluminum nitride, 0.1-1 parts of processing aids, 0.1-0.5 parts of anti-dripping agents, 3-23 parts of composite flame retardants, 1-10 parts of thermal conductive fillers, 2-20 parts of inorganic ceramic fillers and 0.5-3 parts of toughening agents.

3. The method for preparing a ceramic PC film flame retardant material for power batteries according to claim 1, characterized in that: The polycarbonate particles are selected from models L-1250Y and / or 3025IR, the polycarbonate powder is selected from models L-1250WP and / or FN1900; the silane coupling agent is selected from at least one of models KH550, KH560 and KH570.

4. The method for preparing a ceramic PC film flame retardant material for power batteries according to claim 1, characterized in that: The processing aid is selected from model A-3000; the anti-drip agent is selected from model K-PT107 and / or K-PT200.

5. The method for preparing a ceramic PC film flame retardant material for power batteries according to claim 1, characterized in that: In the step (S4), the extrusion process parameters of the twin-screw extruder are: the temperature of zone 1 is controlled at 230-240°C, the temperature of zone 2 is controlled at 260-270°C, the temperature of zone 3 is controlled at 270-280°C, the temperature of zone 4 is controlled at 270-280°C, the temperature of zone 5 is controlled at 260-270°C, the temperature of zone 6 is controlled at 260-270°C, the temperature of zone 7 is controlled at 260-270°C, the temperature of zone 8 is controlled at 260-270°C, the temperature of zone 9 is controlled at 270-280°C, the temperature of zone 10 is controlled at 270-280°C, the head temperature is controlled at 280-285°C, the screw speed is 300-500r / min, the feeding speed is set at 13-18HZ, and the total residence time is controlled at 2-3min.

6. The method for preparing a ceramic PC film flame retardant material for power batteries according to any one of claims 1 to 5, characterized in that: The method for preparing a ceramic PC film from the ceramic PC film flame retardant material comprises the following steps: (R1), take the ceramic PC film flame retardant material and dry it at a temperature of 115-125°C for 3-5 hours; (R2) The ceramic PC film flame retardant material is made into a film by a cast film method, wherein, during the cast film process, the temperature of screw zone A is controlled at 260-270°C, the temperature of screw zone B is controlled at 260-270°C, the temperature of screw zone C is controlled at 270-280°C, and the temperature of the head is controlled at 280-285°C; the main engine speed is controlled at 50-60HZ, the traction speed 1 is set to 8-10m / min, the traction speed 2 is set to 8-10m / min, the traction speed 3 is set to 10-12m / min, the traction speed 4 is set to 10-12m / min, the winding speed is set to 14-16m / min, the film temperature of the roller is set to 98-105°C, the film drawing operation is carried out, and the spacing between the two rollers is adjusted to obtain a ceramic PC film with a thickness of 0.4-0.5mm.

7. A ceramic PC film flame retardant material for power batteries, characterized in that: The material is prepared by the method for preparing a ceramicized PC film flame retardant material dedicated to power batteries as described in any one of claims 1 to 5.

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