A bio-based copolymerized nylon resin and its preparation method, a bio-based copolymerized nylon composite material and its preparation method and application

Abstract

The present invention provides a bio-based copolymerized nylon resin and a preparation method thereof, a bio-based copolymerized nylon composite material and a preparation method and application thereof, belonging to the technical field of nylon resin and composite materials thereof. The water absorption of polyamide materials is mainly caused by the interaction between polar amide bonds and water molecules. The dodecanedioic acid used in the present invention has a longer carbon chain and a lower amide group density, so the water absorption rate of the material is lower and the barrier property to moisture is better. At the same time, the longer the carbon chain, the better the toughness of the material, and the puncture resistance and fatigue resistance are both proportional to the toughness of the material. Therefore, the bio-based copolymerized nylon composite material prepared by the present invention has excellent barrier properties, puncture resistance and fatigue resistance, and can be widely used in the field of soft-pack lithium battery films, effectively solving the current industry problem of insufficient pit depth in nylon film materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of nylon resin and composite materials thereof, and specifically relates to a bio-based copolymerized nylon resin and a preparation method thereof, a bio-based copolymerized nylon composite material and a preparation method and application thereof. Background Art

[0002] Soft-pack lithium-ion batteries, with their advantages of light weight, flexible design, and high energy density, are widely used in 3C electronic products and are gradually expanding into new energy vehicles and energy storage. Aluminum-plastic film, a key component of soft-pack lithium-ion batteries, consists of a surface layer, a middle layer (aluminum foil), and an inner layer (cast polypropylene). This three-layer structure protects the battery's core materials and electrolyte, ultimately determining its safety, stability, and service life. Currently, the outer layer of aluminum-plastic film is typically made of polyester or nylon, requiring excellent impact resistance, puncture resistance, heat resistance, insulation, and friction resistance to protect the inner layer from scratches and mitigate the impact of drops on the battery.

[0003] As the capacity requirements of soft-pack lithium batteries become higher and higher, traditional nylon materials have insufficient toughness, high water absorption rate, and a significant decrease in mechanical strength and electrical performance after moisture absorption, as well as poor dimensional stability. These defects have greatly affected the depth of the pits in the aluminum-plastic film, thereby limiting its widespread application in the aluminum-plastic film field. Summary of the Invention

[0004] In view of this, the present invention aims to provide a bio-based copolymer nylon resin and its preparation method, as well as a bio-based copolymer nylon composite material and its preparation method and application. The bio-based copolymer nylon composite material provided by the present invention is environmentally friendly, has low water absorption, good dimensional stability, good electrical properties, and excellent toughness and resilience, and can effectively increase the depth of the crater when used in lithium battery separators.

[0005] In order to achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a bio-based copolymer nylon resin, the preparation raw materials of which include water and the following components in parts by weight:

[0007]

[0008] The molar ratio of the adipic acid to the dodecanedioic acid is (0.25-4):1; the ratio of the total molar amount of the adipic acid and the dodecanedioic acid to the molar amount of pentamethylenediamine is 1:(1-1.03).

[0009] Preferably, the relative viscosity of the bio-based copolymer nylon resin is 2.6 to 2.8.

[0010] Preferably, the catalyst includes one or more of sodium hypophosphite, sodium phosphite, phosphate and hypophosphite; the end-capping agent includes one or more of benzoic acid, terephthalic acid and 2-naphthalenecarboxylic acid; and the auxiliary agent includes a metal salt.

[0011] The present invention provides a method for preparing the bio-based copolymer nylon resin described in the above scheme, comprising the following steps:

[0012] Adipic acid, dodecanedioic acid, pentamethylenediamine and water are mixed and neutralized to obtain a mixed solution of PA56 salt and PA512 salt;

[0013] Mixing the catalyst, the end-capping agent, and the auxiliary agent with the mixed solution of the PA56 salt and the PA512 salt, and sequentially performing concentration and oligomerization reactions to obtain a PA56 / 512 oligomer;

[0014] The PA56 / 512 oligomer is polymerized under vacuum conditions to obtain a bio-based copolymerized nylon resin.

[0015] Preferably, the mass concentration of the mixed solution of PA56 salt and PA512 salt is 50-60%.

[0016] Preferably, the temperature of the oligomerization reaction is 200° C., the pressure is 1.5 to 1.7 MPa, and the time is 1 to 2 h; the temperature of the polymerization reaction is 240 to 280° C., the time is 1 to 1.5 h, and the vacuum degree is -0.05 to -0.1 MPa.

[0017] The present invention provides a bio-based copolymer nylon composite material, which comprises the following raw materials in parts by weight based on 100 parts of the total amount:

[0018]

[0019] Preferably, the relative viscosity of the nylon MXD10 is 2.0 to 4.5; the compatibilizer includes one or more of ethylene acrylate copolymer, ethylene-octene copolymer grafted with maleic anhydride and glycidyl methacrylate functional group grafted modified polyether block amide copolymer; the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant TNP, antioxidant TPP and antioxidant 264; and the other additives include a lubricant.

[0020] This method provides a method for preparing the bio-based copolymer nylon composite material described in the above scheme, comprising the following steps:

[0021] The bio-based copolymer nylon resin, nylon MXD10, a compatibilizer, an antioxidant and other additives are mixed, and the mixture is melt-extruded, pulled and granulated to obtain a bio-based copolymer nylon composite material.

[0022] The present invention provides the use of the bio-based copolymer nylon composite material described in the above scheme or the bio-based copolymer nylon composite material prepared by the preparation method described in the above scheme in soft-pack lithium battery films.

[0023] The present invention provides a bio-based copolymer nylon resin. The raw materials for preparation include water and the following components in parts by weight: 100 parts of adipic acid, dodecanedioic acid, and pentamethylenediamine; 0.02-0.1 parts of a catalyst; 0.1-0.5 parts of an end-capping agent; and 0.05-0.5 parts of an additive. The molar ratio of the adipic acid to dodecanedioic acid is (0.25-4):1; and the ratio of the total molar amount of the adipic acid and dodecanedioic acid to the molar amount of pentamethylenediamine is 1:(1-1.03). The present invention uses long-chain aliphatic dodecanedioic acid, adipic acid, and pentamethylenediamine as comonomers to prepare a bio-based polyamide PA56 salt and a long-chain all-bio-based polyamide PA512 salt. The PA56 salt and the PA512 salt are then copolymerized to innovatively prepare a bio-based copolymer nylon resin, designated as PA56 / 512. It combines the advantages of ordinary polyamides such as high strength, high melting point, solvent resistance and wear resistance, while being green and environmentally friendly, with low water absorption, good dimensional stability, and excellent toughness and resilience.

[0024] The present invention provides a bio-based copolymer nylon composite material, which includes the following raw materials in parts by weight based on 100 parts of the total amount: 60 to 86 parts of bio-based copolymer nylon resin; 10 to 20 parts of nylon MXD10; 1 to 5 parts of compatibilizer; 0.1 to 0.5 parts of antioxidant; and 0.1 to 2 parts of other additives. The bio-based copolymer nylon composite material provided by the present invention is a bio-based polyamide, which is more environmentally friendly than traditional petroleum-based polyamide. The water absorption of polyamide materials is mainly caused by the interaction between polar amide bonds and water molecules. The dodecanedioic acid used in the present invention has a longer carbon chain and a lower amide group density, so the water absorption rate of the material is lower and the barrier property to moisture is better. At the same time, the longer the carbon chain, the better the toughness of the material, and the puncture resistance and fatigue resistance are both proportional to the toughness of the material. Therefore, the bio-based copolymer nylon composite material provided by the present invention has excellent barrier properties, puncture resistance and fatigue resistance, and can be widely used in the field of soft-pack lithium battery films, effectively solving the current industry problem of insufficient pit depth in nylon film materials. At the same time, because the bio-based copolymer nylon composite material provided by the present invention has low water absorption and good fatigue resistance, it has broad application prospects in the fields of military industry, aerospace, rail transportation, automobiles, engineering machinery, electronic appliances, etc.

[0025] Since longer non-polar methylene groups (derived from dodecanedioic acid) are introduced into the molecular chains of the bio-based copolymer nylon composite material provided by the present invention, the hydrogen bond density is reduced, the disadvantage of the nylon material being easily absorbent is greatly improved, and the dimensional stability and toughness of the bio-based copolymer nylon composite material are improved.

[0026] The present invention provides a method for preparing the bio-based copolymer nylon composite material described in the above scheme. The method comprises mixing a bio-based copolymer nylon resin, nylon MXD10, a compatibilizer, an antioxidant and other additives, and subjecting the mixture to melt extrusion, pulling and granulation to obtain the bio-based copolymer nylon composite material, thereby improving the dimensional stability, barrier properties and puncture resistance of the material. The preparation method provided by the present invention is simple to operate and highly efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 The water vapor equilibrium transmission rate test results of the film in Comparative Example 1;

[0029] Figure 2 The water vapor equilibrium transmission rate test results of the film in Example 8;

[0030] Figure 3 The oxygen equilibrium transmission rate test results of the film in Comparative Example 1;

[0031] Figure 4 The oxygen equilibrium transmission rate test results of the film in Example 8 are shown. DETAILED DESCRIPTION

[0032] The present invention provides a bio-based copolymer nylon resin, the preparation raw materials of which include water and the following components in parts by weight:

[0033]

[0034] The molar ratio of the adipic acid to the dodecanedioic acid is (0.25-4):1; the ratio of the total molar amount of the adipic acid and the dodecanedioic acid to the molar amount of pentamethylenediamine is 1:(1-1.03).

[0035] In the present invention, unless otherwise specified, all raw materials used are commercially available products well known in the art.

[0036] In the present invention, the raw materials for preparing the bio-based copolymerized nylon resin include, by weight, 100 parts of adipic acid, dodecanedioic acid, and pentamethylenediamine. In the present invention, the molar ratio of adipic acid to dodecanedioic acid is (0.25-4):1, preferably (0.5-3):1, and more preferably (1-2.5):1; and the ratio of the total molar amount of adipic acid and dodecanedioic acid to the molar amount of pentamethylenediamine is 1:(1-1.03).

[0037] The raw materials for preparing the bio-based copolymerized nylon resin of the present invention include 0.02 to 0.1 parts of a catalyst, preferably 0.04 to 0.08 parts, based on the total weight of the adipic acid, dodecanedioic acid, and pentamethylenediamine. In the present invention, the catalyst preferably includes one or more of sodium hypophosphite, sodium phosphite, a phosphate ester, and a hypophosphite ester.

[0038] The raw materials for preparing the bio-based copolymerized nylon resin of the present invention include 0.1 to 0.5 parts of an end-capping agent, preferably 0.2 to 0.4 parts, based on the total weight of adipic acid, dodecanedioic acid, and pentamethylenediamine. In the present invention, the end-capping agent preferably includes one or more of benzoic acid, terephthalic acid, and 2-naphthalenecarboxylic acid. The end-capping agent of the present invention can control the molecular weight of the bio-based copolymerized nylon resin.

[0039] Based on the total weight of adipic acid, dodecanedioic acid, and pentamethylenediamine, the raw materials for preparing the bio-based copolymerized nylon resin of the present invention include 0.05-0.5 parts of an additive, preferably 0.1-0.3 parts. In the present invention, the additive preferably comprises a metal salt; the metal salt preferably comprises a magnesium salt and / or a zinc salt; the magnesium salt is preferably magnesium chloride and / or magnesium bromide; and the zinc salt is preferably one or more of zinc chloride, zinc bromide, and zinc borate. In the present invention, the metal salt can act as a heterogeneous nucleation agent, simultaneously controlling the crystallization rate and grain size.

[0040] Based on the total mass fraction of the adipic acid, dodecanedioic acid and pentamethylenediamine, the raw materials for preparing the bio-based copolymer nylon resin of the present invention include water.

[0041] In the present invention, the relative viscosity of the bio-based copolymer nylon resin is preferably 2.6 to 2.8, more preferably 2.7. In the present invention, relative viscosity is used to measure molecular weight: a relative viscosity ≤ 2.0 indicates a low molecular weight; a relative viscosity ≥ 2.5 indicates a high molecular weight. The PA56 / 512 produced in the present invention preferably has a high molecular weight.

[0042] The present invention provides a method for preparing the bio-based copolymer nylon resin described in the above scheme, comprising the following steps:

[0043] Adipic acid, dodecanedioic acid, pentamethylenediamine and water are mixed and neutralized to obtain a mixed solution of PA56 salt and PA512 salt;

[0044] Mixing the catalyst, the end-capping agent, and the auxiliary agent with the mixed solution of the PA56 salt and the PA512 salt, and sequentially performing concentration and oligomerization reactions to obtain a PA56 / 512 oligomer;

[0045] The PA56 / 512 oligomer is polymerized under vacuum conditions to obtain a bio-based copolymerized nylon resin.

[0046] The invention mixes adipic acid, dodecanedioic acid, pentamethylenediamine and water, and performs a neutralization reaction to obtain a mixed solution of PA56 salt and PA512 salt.

[0047] In the present invention, the mixing of adipic acid, dodecanedioic acid, pentamethylenediamine, and water preferably comprises mixing adipic acid, dodecanedioic acid, and water to obtain a suspension, followed by the addition of pentamethylenediamine. In the present invention, the water is preferably deionized water; the mixing is preferably performed under stirring at atmospheric pressure; the stirring speed is preferably 100-150 rpm, more preferably 110-140 rpm, and even more preferably 120-130 rpm. In the present invention, the stirring is preferably performed until the system forms a white suspension, followed by the temperature being raised to 80°C and the addition of pentamethylenediamine.

[0048] In the present invention, the neutralization reaction is preferably carried out under stirring; the stirring speed is preferably 180-300 rpm, more preferably 200-250 rpm, and even more preferably 210-240 rpm. In the present invention, the neutralization reaction time is preferably 1-2 hours, more preferably 1.2-1.8 hours; the neutralization reaction time is preferably calculated from the completion of the addition of pentamethylenediamine. In the present invention, the PA56 salt is obtained by the neutralization reaction of adipic acid and pentamethylenediamine; the PA512 salt is obtained by the neutralization reaction of dodecanedioic acid and pentamethylenediamine.

[0049] After the neutralization reaction is completed, the present invention preferably uses pentamethylenediamine to adjust the pH of the resulting salt solution to 7.5-7.9, thereby obtaining a mixed solution of PA56 salt and PA512 salt. In the present invention, the mass concentration of the mixed solution of PA56 salt and PA512 salt is preferably 50-60%, more preferably 52-58%. The amount of water used is determined by the mass concentration of the mixed solution of PA56 salt and PA512 salt. Adjusting the pH to 7.5-7.9 ensures that the diamine and dibasic acid react in equimolar amounts.

[0050] After obtaining the mixed solution of PA56 salt and PA512 salt, the present invention mixes the mixed solution of PA56 salt and PA512 salt with a catalyst, a capping agent, and an auxiliary agent, and sequentially performs concentration and oligomerization reactions to obtain PA56 / 512 oligomers.

[0051] In the present invention, the concentration and oligomerization reactions are preferably carried out in an autoclave. The concentration preferably includes replacing the air in the autoclave with nitrogen three to five times, followed by heating to 140-160°C, more preferably 145-155°C. In the present invention, the concentration is preferably carried out at a pressure of 1.5 MPa. The concentration is preferably carried out until the water content of the resulting mixed solution is 20% by weight. By controlling the water content, the molecular weight of the oligomers subsequently prepared can be controlled.

[0052] In the present invention, the temperature of the oligomerization reaction is preferably 200°C; the pressure of the oligomerization reaction is preferably 1.5-1.7 MPa, more preferably 1.6 MPa; and the duration of the oligomerization reaction is preferably 1-2 hours, more preferably 1.2-1.8 hours. In the present invention, the oligomerization reaction is a condensation reaction between PA56 salt and PA512 salt; the molecular weight of the PA56 / 512 oligomer is determined by the reaction temperature and reaction pressure.

[0053] After obtaining the PA56 / 512 oligomer, the present invention performs a polymerization reaction on the PA56 / 512 oligomer under vacuum conditions to obtain a bio-based copolymerized nylon resin.

[0054] In the present invention, the polymerization reaction is preferably carried out in an autoclave. The pressure in the autoclave is preferably maintained at 1.6 MPa, the temperature is then raised to the polymerization reaction temperature, the steam in the autoclave is gradually released to reduce the pressure to atmospheric pressure, and then vacuum is drawn.

[0055] In the present invention, the polymerization reaction temperature is preferably 240-280° C., more preferably 250-270° C., and more preferably 255-260° C.; the polymerization reaction time is preferably 1-1.5 h, and more preferably 1.2-1.4 h.

[0056] In the present invention, the time for gradually releasing the steam in the autoclave to reduce the pressure in the autoclave to normal pressure is preferably 45 to 90 minutes. In the present invention, the vacuum degree of the polymerization reaction is preferably -0.05 to -0.1 MPa, and more preferably -0.06 to -0.08 MPa. In the present invention, the polymerization reaction occurs while the vacuum is being drawn. In the present invention, the pressure in the autoclave is initially maintained at 1.6 MPa to prevent the volatilization of pentamethylenediamine. In the polymerization reaction of the present invention, the PA56 / 512 oligomers further undergo polycondensation, achieving a significant increase in molecular weight to form a bio-based copolymerized nylon resin.

[0057] This invention uses long-chain aliphatic dodecanedioic acid, adipic acid, and pentamethylenediamine as comonomers to produce bio-based polyamide PA56 and long-chain, all-bio-based polyamide PA512. PA56 and PA512 are then copolymerized to create an innovative bio-based copolymer nylon resin, designated PA56 / 512. This product combines the advantages of conventional polyamides, such as high strength, high melting point, solvent resistance, and abrasion resistance, while also being environmentally friendly, exhibiting low water absorption, good dimensional stability, and superior toughness and resilience.

[0058] The present invention provides a bio-based copolymer nylon composite material, which comprises the following raw materials in parts by weight based on 100 parts of the total weight:

[0059]

[0060] In the present invention, based on 100 parts by weight, the raw materials for preparing the bio-based copolymer nylon composite material include 60 to 86 parts by weight of bio-based copolymer nylon resin, preferably 65 to 80 parts, and more preferably 65 to 72 parts.

[0061] The raw materials for preparing the bio-based copolymerized nylon composite material include 10 to 20 parts by weight of nylon MXD10, preferably 12 to 18 parts by weight, per 100 parts by weight. In the present invention, the relative viscosity of the nylon MXD10 is preferably 2.0 to 4.5, more preferably 2.5 to 4. In the present invention, the addition of nylon MXD10 can further improve the barrier properties of the film, such as its ability to block water vapor and oxygen.

[0062] The raw materials for preparing the bio-based copolymer nylon composite material include 1 to 5 parts of a compatibilizer, preferably 1.2 to 4 parts, and more preferably 2 to 3.5 parts, based on 100 parts by weight. In the present invention, the compatibilizer preferably includes one or more of ethylene acrylate copolymer, ethylene-octene copolymer grafted with maleic anhydride (POE-g-MAH), and glycidyl methacrylate functional group-grafted modified polyether block amide copolymer.

[0063] The raw materials for preparing the bio-based copolymer nylon composite material include 0.1 to 0.5 parts of antioxidant, preferably 0.2 to 0.4 parts, based on 100 parts by weight. In the present invention, the antioxidant preferably includes one or more of antioxidant 1010, antioxidant 168, antioxidant TNP, antioxidant TPP, and antioxidant 264.

[0064] The raw materials for preparing the bio-based copolymer nylon composite material include 0.1 to 2 parts of other additives, preferably 0.5 to 1.5 parts, based on 100 parts by weight. In the present invention, the other additives preferably include a lubricant; the lubricant preferably includes one or more of oleamide, erucamide, ethylene bisstearamide, and gall wax.

[0065] The bio-based copolymer nylon composite material provided by the present invention is a bio-based polyamide, which is more environmentally friendly than traditional petroleum-based polyamides. Water absorption in polyamide materials is primarily caused by the interaction of polar amide bonds with water molecules. The dodecanedioic acid used in the present invention has a longer carbon chain and a lower amide group density, resulting in a lower water absorption rate and improved moisture barrier properties. Furthermore, the longer carbon chain improves the material's toughness, and both puncture resistance and fatigue resistance are directly proportional to the material's toughness. Therefore, the bio-based copolymer nylon composite material provided by the present invention exhibits excellent barrier properties, puncture resistance, and fatigue resistance.

[0066] Since longer non-polar methylene groups (derived from dodecanedioic acid) are introduced into the molecular chains of the bio-based copolymer nylon composite material provided by the present invention, the hydrogen bond density is reduced, the disadvantage of the nylon material being easily absorbent is greatly improved, and the dimensional stability and toughness of the bio-based copolymer nylon composite material are improved.

[0067] The present invention provides a method for preparing the bio-based copolymer nylon composite material described in the above scheme, comprising the following steps:

[0068] The bio-based copolymer nylon resin, nylon MXD10, a compatibilizer, an antioxidant and other additives are mixed, and the mixture is melt-extruded, pulled and granulated to obtain a bio-based copolymer nylon composite material.

[0069] In the present invention, the melt extrusion is preferably carried out in an extruder, and the temperature of the extruder barrel is preferably 210-220°C, more preferably 212-216°C; the temperature of the extruder conveying section is preferably 220-260°C, more preferably 230-250°C, more preferably 235-245°C; the temperature of the extruder compression section is preferably 230-260°C, more preferably 235-250°C, more preferably 240-245°C; the temperature of the extruder metering section is preferably 230-260°C ℃, more preferably 235-250℃, more preferably 240-245℃; the extruder nozzle temperature is preferably 235-265℃, more preferably 240-260℃, more preferably 245-250℃; the extruder screw speed is preferably 180-200r / min, more preferably 185-195r / min, more preferably 187-193r / min; the extruder feeding speed is preferably 15-20r / min, more preferably 16-18r / min.

[0070] The present invention can improve the dimensional stability, barrier properties and puncture resistance of the material through the above-mentioned preparation method; and the preparation method provided by the present invention is simple to operate and highly efficient.

[0071] The present invention provides the use of the bio-based copolymer nylon composite material described in the above scheme or the bio-based copolymer nylon composite material prepared by the preparation method described in the above scheme in soft-pack lithium battery films.

[0072] The bio-based copolymer nylon composite material provided by the present invention exhibits excellent barrier properties, puncture resistance, and fatigue resistance, making it widely applicable in the field of soft-pack lithium battery thin films, effectively resolving the current industry challenge of insufficient crater depth in nylon membrane materials. Furthermore, due to its low water absorption and excellent fatigue resistance, the bio-based copolymer nylon composite material provided by the present invention has broad application prospects in the fields of military, aerospace, rail transportation, automobiles, engineering machinery, and electronic appliances.

[0073] To further illustrate the present invention, a bio-based copolymer nylon resin and its preparation method, a bio-based copolymer nylon composite material and its preparation method and application provided by the present invention are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0074] Examples 1 to 7

[0075] According to the raw material formula in Table 1, adipic acid, dodecanedioic acid, and deionized water were mixed and stirred at normal pressure at 120 rpm until the system became a white suspension. The temperature was then raised to 80°C, pentamethylenediamine was added, and the mixture was vigorously stirred at 180 rpm for 1 hour. The pH of the resulting salt solution was adjusted to 7.8 with pentamethylenediamine to obtain a mixed solution of PA56 salt and PA512 salt with a mass concentration of 50%.

[0076] The mixed solution of PA56 salt and PA512 salt was added to an autoclave, followed by the addition of a catalyst, a capping agent, and an auxiliary agent. The air in the autoclave was replaced with nitrogen three times, and then the temperature was raised to 150° C., the pressure was maintained at 1.5 MPa, and the water content of the mixed solution was controlled to 20% (concentrated) by draining. The temperature in the autoclave was raised to 200° C., the air was removed by nitrogen, the pressure was maintained at 1.6 MPa, and the reaction was carried out for 1 hour to prepare a PA56 / 512 oligomer.

[0077] The pressure was maintained at 1.6 MPa, and the temperature in the kettle was raised to 250°C. After the temperature was reached, the steam in the polymerization kettle was gradually released to reduce the pressure in the kettle to 0. Then, vacuum was applied and the vacuum degree was maintained at -0.06 MPa for 1 hour. Finally, a significant increase in molecular weight was achieved at 270°C to prepare the copolymer nylon resin PA56 / 512.

[0078] Table 1 Bio-based copolymer nylon resin raw material formula in Examples 1 to 7

[0079] serial number Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Pentamethylenediamine (kg) 10.5 10.5 10.5 10.5 10.5 10.5 10.5 Adipic acid (kg) 11.68 10.22 8.76 7.3 5.84 4.38 2.92 Dodecanedioic acid (kg) 4.6 6.9 9.2 11.5 13.2 16.1 18.4 Deionized water (kg) 25 25 25 25 25 25 25 Sodium hypophosphite (g) 12 12 12 12 12 12 12 Benzoic acid (g) 75 75 75 75 75 75 75 Magnesium chloride (g) 50 50 50 50 50 50 50

[0080] Examples 8 to 11

[0081] The bio-based copolymer nylon resin (PA56:PA512=4:6) prepared in Example 5 was used to prepare a bio-based copolymer nylon composite material according to the formulation in Table 2 using the following preparation method:

[0082] The bio-based copolymer nylon resin, nylon MXD10, a compatibilizer, an antioxidant and a lubricant are mixed, and the mixture is melt-extruded, pulled and pelletized to obtain a bio-based copolymer nylon composite material;

[0083] The melt extrusion is carried out in an extruder, and the extruder barrel mouth temperature is 210°C, the conveying section temperature is 240°C, the compression section temperature is 245°C, the metering section temperature is 240°C, the nozzle temperature is 255°C, the screw speed is 200r / min, and the feeding speed is 15r / min.

[0084] Comparative Examples 1-2

[0085] The same preparation method as in Example 8 was used to prepare a copolymerized nylon composite material according to the formulation in Table 2. The formulations of the copolymerized nylon composite materials of Examples 8-11 and Comparative Examples 1-2 are shown in Table 2. Comparative Example 1 is a standard nylon composite material formulation for lithium battery separators currently available on the market.

[0086] Table 2 Formula of copolymerized nylon composite materials of Examples 8 to 11 and Comparative Examples 1 to 2 (parts by weight)

[0087]

[0088] Performance Testing

[0089] (1) The hygroscopicity evaluation of the bio-based copolymer nylon resin PA56 / 512 prepared in Examples 1 to 7 is shown in Table 3 (hygroscopicity refers to the water absorption rate test of the material, and the test standard is GB / T 1034). The toughness evaluation is shown in Table 4 (toughness refers to the impact strength test of the material, and the test standard is GB / T 1043.1).

[0090] Table 3 Material water absorption test

[0091]

[0092]

[0093] In Examples 1 to 7, the PA512 content increases sequentially. As can be seen from Table 3, the water absorption rate of the bio-based copolymer nylon resin PA56 / 512 decreases with the increase of PA512 content;

[0094] Table 4 Material elongation at break test

[0095]

[0096] It can be seen from Table 4 that the elongation at break of the bio-based copolymer nylon resin PA56 / 512 is improved, and the copolymer nylon resin PA56 / 512 prepared in Example 5 has the highest elongation at break, which is helpful for the crater depth of the film.

[0097] (2) The barrier properties of bio-based copolymer nylon composite materials were evaluated by casting and double drawing to make films.

[0098] aPreparation of cast film

[0099] The copolymer nylon composite material prepared in Table 2 was cast on a casting machine. The temperature setting values of the 6 zones of the casting machine (starting from the feed port and sequentially to the die port) were: 220°C, 235°C, 255°C, 265°C, 255°C and 255°C, respectively. The extrusion speed was 20r / min. After extrusion, the film was cooled on a casting roller at 30°C to form a film. The direction of the casting film was set to the MD direction (longitudinal direction), and the direction perpendicular to the casting was set to the TD direction (transverse direction) to obtain a cast film.

[0100] b Preparation of biaxially oriented film

[0101] The cast film was biaxially stretched using a biaxial tensile testing machine. First, the cast film was cut into 100 x 100 mm square sheets. The film was then placed in the sample loading area of the tensile testing machine, with the four sides of the square secured with clips. The following settings were used: stretching time of 0.5 seconds, preheating temperature of 10°C below the crystallization peak temperature, preheating time of 90 seconds, heat setting temperature of 20°C below the melting onset temperature, setting time of 60 seconds, stretch ratio of 3 x 3, and stretch rate of 100%.

[0102] c Performance test of biaxially oriented film

[0103] The films of Examples 8 to 11 and Comparative Examples 1 to 2 were subjected to performance tests. The test results are shown in Table 5.

[0104] Table 5 Test results of film properties of various embodiments and comparative examples

[0105]

[0106] As shown in Table 5, Example 8 and Comparative Example 2 demonstrate that the introduction of a bio-based long carbon chain (derived from dodecanedioic acid) significantly reduces the water absorption rate of the bio-based copolymer nylon composite, ensuring the composite's tensile strength after balanced water absorption. Furthermore, because the bio-based copolymer nylon resin combines both strength and toughness, it effectively increases the depth of the punched hole used in lithium battery separators. Furthermore, by compounding nylon MXD10 with the bio-based copolymer nylon resin PA56 / 512, the barrier properties of the bio-based copolymer nylon composite are further enhanced.

[0107] Although nylon MXD10 can improve the barrier properties of the composite material, it can be seen from Comparative Example 2 and Examples 9 to 11 in Table 5 that as the MXD10 content increases, the tensile strength of the material increases, but the elongation at break decreases, indicating a decrease in toughness. This will affect the pit depth of the lithium battery separator when the product is used, so it should be added in an appropriate amount.

[0108] It can be seen from Comparative Example 2 and Comparative Example 1 in Table 5 that nylon MXD10 can reduce the water absorption rate of the composite material; it can be seen from Comparative Example 2 and Example 9 that the water absorption rate of Example 9 is lower, indicating that the long carbon chain bio-based copolymer nylon PA56 / 512 is more effective in reducing the water absorption rate.

[0109] It can be seen from Examples 8 and 10 in Table 5 that the optimal addition ratio of the compatibilizer is 4 parts. As the amount of compatibilizer added decreases, the water absorption rate of the composite material increases and the barrier performance decreases.

[0110] This invention combines a self-made bio-based copolymerized nylon resin, PA56 / 512, with nylon MXD10, achieving both strength and toughness. The composite material exhibits advantages such as low water absorption and dimensional stability. Films made from this composite material exhibit excellent barrier properties, puncture resistance, and fatigue resistance.

[0111] Figure 1 The water vapor equilibrium transmission rate test results of the film in Comparative Example 1; Figure 2 is the test result of water vapor equilibrium transmission rate of the film in Example 8; Figures 1-2 It can be seen that the water vapor equilibrium permeability of the biaxially oriented film is Figure 1 130.8g / (m 2 -day) to Figure 2 57.2g / (m 2 -day), the water vapor barrier performance of the film prepared from the bio-based copolymer nylon composite material of Example 8 of the present application was improved by 56.2% compared with that of Comparative Example 1.

[0112] Figure 3 The oxygen equilibrium transmission rate test results of the film in Comparative Example 1; Figure 4 The oxygen equilibrium transmission rate test results of the film in Example 8 are as follows. Figures 3-4 It can be seen that the oxygen equilibrium permeability of the film is given by Figure 3 107.1cc / (m 2 -day) to Figure 4 58.8cc / (m 2-day), the oxygen barrier performance of the film prepared from the bio-based copolymer nylon composite material of Example 8 of the present application was improved by 45.1% compared with that of Comparative Example 1. The improved barrier performance of the film effectively protects the battery core material and electrolyte, and improves the safety, stability and service life of the battery.

[0113] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A bio-based copolymer nylon composite material, the total amount of which is 100 parts, consisting of the following raw materials in parts by weight: The raw materials for preparing the bio-based copolymer nylon resin are water and the following components in parts by weight: The molar ratio of the adipic acid to the dodecanedioic acid is (0.25-4):1; the ratio of the total molar amount of the adipic acid and the dodecanedioic acid to the molar amount of pentamethylenediamine is 1:(1-1.03).

2. The bio-based copolymer nylon composite material according to claim 1, characterized in that: The relative viscosity of the bio-based copolymer nylon resin is 2.6-2.

8.

3. The bio-based copolymer nylon composite material according to claim 1 or 2, characterized in that: The catalyst includes one or more of sodium hypophosphite, sodium phosphite, phosphate and hypophosphite; the end-capping agent includes one or more of benzoic acid, terephthalic acid and 2-naphthalenecarboxylic acid; and the auxiliary agent includes a metal salt.

4. The bio-based copolymer nylon composite material according to claim 1 or 2, characterized in that: The following steps are involved: Adipic acid, dodecanedioic acid, pentamethylenediamine and water are mixed and neutralized to obtain a mixed solution of PA56 salt and PA512 salt; Mixing the catalyst, the end-capping agent, and the auxiliary agent with the mixed solution of the PA56 salt and the PA512 salt, and sequentially performing concentration and oligomerization reactions to obtain a PA56 / 512 oligomer; The PA56 / 512 oligomer is polymerized under vacuum conditions to obtain a bio-based copolymerized nylon resin.

5. The bio-based copolymer nylon composite material according to claim 4, characterized in that: The mass concentration of the mixed solution of PA56 salt and PA512 salt is 50-60%.

6. The bio-based copolymer nylon composite material according to claim 4, characterized in that: The temperature of the oligomerization reaction is 200° C., the pressure is 1.5-1.7 MPa, and the time is 1-2 hours; the temperature of the polymerization reaction is 240-280° C., the time is 1-1.5 hours, and the vacuum degree is -0.05--0.1 MPa.

7. The bio-based copolymer nylon composite material according to claim 1, wherein the relative viscosity of the nylon MXD10 is 2.0 to 4.5; the compatibilizer comprises one or more of ethylene acrylate copolymer, ethylene-octene copolymer grafted with maleic anhydride, and polyether block amide copolymer grafted with glycidyl methacrylate functional groups; the antioxidant comprises one or more of antioxidant 1010, antioxidant 168, antioxidant TNP, antioxidant TPP, and antioxidant 264; and the other additives include a lubricant.

8. The method for preparing the bio-based copolymer nylon composite material according to any one of claims 1 to 7, comprising the following steps: The bio-based copolymer nylon resin, nylon MXD10, a compatibilizer, an antioxidant and other additives are mixed, and the mixture is melt-extruded, pulled and granulated to obtain a bio-based copolymer nylon composite material.

9. Use of the bio-based copolymer nylon composite material according to any one of claims 1 to 7 or the bio-based copolymer nylon composite material prepared by the preparation method according to claim 8 in soft-pack lithium battery films.

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