Compositions for preparing modified BOPA films, modified BOPA films, their preparation methods and applications

Abstract

This invention discloses a composition for preparing modified BOPA films, the modified BOPA films, their preparation methods, and applications. The composition comprises: a barrier blend, a first thermally conductive blend, and a second thermally conductive blend; wherein the barrier blend comprises: a matrix resin, surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, a rheology modifier, a compatibilizer, and an antioxidant; the first thermally conductive blend comprises: polyamide, surface-functionalized graphene oxide, a liquid crystal polymer, a rheology modifier, a compatibilizer, and an antioxidant; the second thermally conductive blend comprises: polyamide, surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, a rheology modifier, a compatibilizer, and an antioxidant. This invention obtains modified BOPA films with improved thermal conductivity and barrier properties by modifying the fillers and then employing co-extrusion combined with longitudinal and transverse biaxial stretching.

Description

Technical Field

[0001] This invention belongs to the field of biaxially oriented film packaging, specifically relating to a composition for preparing modified BOPA film, the modified BOPA film, its preparation method and application. Background Technology

[0002] Biaxially oriented polyamide (BOPA) film is the third largest polymeric film packaging material after biaxially oriented polypropylene (BOPP) film and biaxially oriented polyethylene terephthalate (BOPET) film. Compared with BOPP and BOPET films, BOPA film has a wider operating temperature range (-60~150℃), better gas barrier properties, and excellent puncture resistance, abrasion resistance, and solvent resistance. Since its inception, BOPA's most successful and representative application area has been food packaging, where it still accounts for over 70% of the market share; followed by the daily chemical industry, accounting for approximately 18%; and then approximately 5%, 3%, and 2% in the pharmaceutical, electronics, and pouch battery industries, respectively.

[0003] Due to the high technological maturity of BOPA film for food packaging, the market has largely become a competition of scale and price, leading to increasingly fierce competition and mounting pressure on related companies. Conversely, with the rapid development of the new energy and microelectronics industries, the demand for packaging materials for batteries, chips, and circuit boards is rising rapidly, creating a vast blue ocean market. However, as the integration, operating frequency, and power density of electronic devices continue to increase, overheating problems are becoming more severe, placing higher demands on the thermal conductivity of packaging materials. Furthermore, many electronic components and military equipment require moisture and oxidation protection, placing high demands on barrier properties. Although BOPA film offers significantly better barrier properties than other two types, this barrier property is still insufficient to meet the packaging requirements of precision components, and BOPA itself has relatively poor thermal conductivity.

[0004] Numerous public reports exist on BOPA films, primarily focusing on improving their barrier properties. Patent CN106671534A discloses a co-extruded biaxially oriented polyamide film containing polyester and its preparation method. The film consists of three layers: A, B, and C. Layer A is a polyester layer, layer B is an adhesive layer, and layer C is a polyamide layer. Layer A: 98.5–99.4% polyester, 0.5–1% anti-sticking agent, 0.1–0.5% slip agent; Layer B: 100% adhesive layer; Layer C: 98.5–99.4% polyamide, 0.5–1% anti-sticking agent, 0.1–0.5% slip agent. The polyamide film obtained by this invention exhibits good toughness, excellent gas barrier properties, and superior heat and chemical corrosion resistance, making it widely applicable to various food and industrial uses, particularly suitable for high-temperature retortable food packaging and lithium battery packaging. For example, patent CN105722899A discloses a biaxially stretched nylon film for cold forming. The biaxially stretched nylon film is characterized by having at least one side coated with a water-based resin such as polyurethane and a crosslinking agent. This coating layer can maintain excellent cold formability and is not prone to delamination between layers under high temperature and high humidity, making it particularly suitable as a main substrate for cold-forming packaging materials, especially for packaging materials used in the outer shell of lithium-ion secondary batteries. Patent CN102431239A discloses a polymer lithium-ion battery core outer packaging molding material. Its outer barrier layer is composed of a single layer or co-extruded composite of heat-resistant PET, BOPA, and PEN. The aluminum foil in the barrier layer contains at least 0.9-1.5 wt% iron. The high barrier layer includes a base layer, a functional layer, and a heat-sealing layer. The base layer is composed of at least two combinations or composites of CPP, PET, PA or MXD6, MPE elastomer, PVDC, EVOH, and PEN. The copolymer film is coated with high-barrier, water-resistant modified polyvinyl alcohol. This invention solves the problems of electrolyte stability and provides superior barrier properties, making it suitable for battery cell packaging materials. Patent CN1157808C discloses a battery case forming sheet and battery assembly. The battery case forming sheet is formed by sequentially stacking a base film layer, a metal sheet layer, and a thermally bonded resin layer. The base film layer is a biaxially oriented polyethylene terephthalate resin film or a biaxially oriented nylon resin film; the metal sheet layer is an aluminum or copper sheet; and the thermally bonded resin layer is a polyolefin resin. The metal sheet layer provides excellent water vapor and oxygen barrier properties, making it suitable for soft-pack battery packaging materials.

[0005] Although the above-mentioned known technologies can all prepare BOPA films for lithium-ion battery packaging, the following limitations still exist: (1) Under current technological conditions, although the barrier properties of BOPA films can meet the requirements for lithium-ion battery packaging, they are insufficient to meet the barrier requirements of precision components; (2) The metal sheets used in the prior art can play a role in barrier and heat conduction, but the conductivity of the metal itself can easily lead to short circuits in electronic devices; (3) Few patents involve the high thermal conductivity of BOPA films, and BOPA films prepared under existing technological conditions cannot meet the packaging requirements of electronic devices with heat dissipation needs. Therefore, it is imperative to develop a new type of functionalized BOPA film with high barrier, high thermal conductivity, and good electrical insulation properties. Summary of the Invention

[0006] The main objective of this invention is to provide a composition for preparing modified BOPA films, the modified BOPA films, their preparation methods and applications, in order to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] This invention provides a composition for preparing a modified BOPA film, comprising: a barrier blend, a first thermally conductive blend, and a second thermally conductive blend;

[0009] The barrier blend comprises: a matrix resin, surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, rheology modifiers, compatibilizers, and antioxidants, wherein the matrix resin comprises polyamide PA and poly(m-phenylene adipamide) MXD6.

[0010] The first thermally conductive blend comprises: polyamide PA, surface-functionalized graphene oxide (MGO), liquid crystal polymer (LCP), rheology modifier, compatibilizer, and antioxidant;

[0011] The second thermally conductive blend includes: polyamide (PA), surface-functionalized micron-sized thermally conductive filler, surface-functionalized nano-sized thermally conductive filler, rheology modifier, compatibilizer, and antioxidant.

[0012] This invention also provides a method for preparing a modified BOPA film, which includes: using the aforementioned barrier blend, first thermally conductive blend and second thermally conductive blend to perform three-layer co-extrusion to obtain a modified BOPA film;

[0013] The modified BOPA film comprises a surface layer formed by the barrier blend, an intermediate layer formed by the first thermally conductive blend, and an inner layer formed by the second thermally conductive blend.

[0014] This invention also provides a modified BOPA film prepared by the aforementioned method. The modified BOPA film has a transverse tensile strength of 160-260 MPa, a longitudinal tensile strength of 200-300 MPa, a transverse elongation at break of 60%-160%, a longitudinal elongation at break of 40%-140%, a puncture force of 5-15 N, a thermal conductivity of 0.5-1.5 W / (m·K), and an oxygen permeability of 3-13 cm⁻¹. 3 / (m 2 ·d·atm).

[0015] This invention also provides the use of the aforementioned modified BOPA film in the preparation of lithium-ion battery packaging.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) This invention improves the compatibility of fillers and polymers through surface chemical modification, promotes their uniform dispersion, and reduces interfacial thermal resistance.

[0018] (2) This invention achieves high-efficiency thermal conductivity of BOPA film by modifying the thermally conductive fillers at the micron and nano scales in different ways so that they can react with each other, build a "bridge" structure between the thermally conductive particles, and construct a dual-network thermally conductive pathway.

[0019] (3) The present invention achieves synergistic barrier and thermal conductivity properties of BOPA film by combining MXD6 with thermally conductive filler;

[0020] (4) In this invention, the bi-stretch flow field induces LCP to form microfibers, thereby achieving efficient in-plane thermal conductivity of BOPA film;

[0021] (5) In this invention, the surface epoxidized thermally conductive filler (MGO) can react with PA6 or LCP respectively, which will create certain obstacles to the movement and orientation of polymer molecular chains, regulate the distribution of two-dimensional nano thermally conductive filler and LCP microfiber in the vertical direction, construct a three-dimensional thermally conductive path, and realize that BOPA film can conduct heat efficiently in both the in-plane and vertical directions. Detailed Implementation

[0022] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] In this invention, unless otherwise stated, “PA” refers to polyamide; “BOPA” refers to biaxially oriented polyamide; and “MXD6” refers to poly(m-phenylene adipamide).

[0024] Specifically, as one aspect of the technical solution of the present invention, a composition for preparing a modified BOPA film includes: a barrier blend, a first thermally conductive blend, and a second thermally conductive blend;

[0025] The barrier blend comprises: a matrix resin, surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, rheology modifiers, compatibilizers, and antioxidants, wherein the matrix resin comprises polyamide PA and poly(m-phenylene adipamide) MXD6.

[0026] The first thermally conductive blend comprises: polyamide PA, surface-functionalized graphene oxide (MGO), liquid crystal polymer (LCP), rheology modifier, compatibilizer, and antioxidant;

[0027] The second thermally conductive blend includes: polyamide (PA), surface-functionalized micron-sized thermally conductive filler, surface-functionalized nano-sized thermally conductive filler, rheology modifier, compatibilizer, and antioxidant.

[0028] In some preferred embodiments, the barrier blend comprises the following components by weight: 100 parts of matrix resin, 10-25 parts of surface-functionalized micron-sized thermally conductive filler, 5-15 parts of surface-functionalized nano-sized thermally conductive filler, 0.5-5 parts of rheology modifier, 0.1-2 parts of compatibilizer, and 0.1-2 parts of antioxidant, wherein the matrix resin comprises 60-90 parts of poly(m-phenylene adipamide).

[0029] Further, the barrier blend comprises the following components by weight: 100 parts of matrix resin, 15-22 parts of surface-functionalized micron-sized thermally conductive filler, 8-14 parts of surface-functionalized nano-sized thermally conductive filler, 1-4 parts of rheology modifier, 0.5-1.5 parts of compatibilizer, and 0.5-1.5 parts of antioxidant, wherein the matrix resin comprises 70-85 parts of poly(m-phenylene adipamide).

[0030] Furthermore, the barrier blend comprises the following components by weight: 100 parts of matrix resin, 18-20 parts of surface-functionalized micron-sized thermally conductive filler, 10-12 parts of surface-functionalized nano-sized thermally conductive filler, 2-3 parts of rheology modifier, 1-1.2 parts of compatibilizer, and 1-1.2 parts of antioxidant, wherein the matrix resin comprises 75-80 parts of poly(m-phenylene adipamide).

[0031] In some preferred embodiments, the barrier blend is obtained by mixing and extruding a matrix resin, surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, rheology modifiers, compatibilizers, and antioxidants.

[0032] In some preferred embodiments, the first thermally conductive blend comprises the following components in parts by weight: 100 parts polyamide PA, 5-15 parts surface-functionalized graphene oxide (MGO), 10-25 parts liquid crystal polymer (LCP), 0.5-5 parts rheology modifier, 0.1-2 parts compatibilizer, and 0.1-2 parts antioxidant.

[0033] Further, the first thermally conductive blend comprises the following components in parts by weight: 100 parts polyamide PA, 8-13 parts surface-functionalized graphene oxide (MGO), 12-22 parts liquid crystal polymer (LCP), 1-4 parts rheology modifier, 0.5-1.5 parts compatibilizer, and 0.5-1.5 parts antioxidant.

[0034] Furthermore, the first thermally conductive blend comprises the following components in parts by weight: 100 parts polyamide PA, 10-12 parts surface-functionalized graphene oxide (MGO), 16-20 parts liquid crystal polymer (LCP), 2-3 parts rheology modifier, 1-1.2 parts compatibilizer, and 1-1.2 parts antioxidant.

[0035] In some preferred embodiments, the first thermally conductive blend is obtained by extrusion granulation of polyamide PA, surface-functionalized graphene oxide (MGO), liquid crystal polymer (LCP), rheology modifier, compatibilizer and antioxidant.

[0036] In some preferred embodiments, the second thermally conductive blend comprises the following components by weight: 100 parts polyamide PA, 10-25 parts surface-functionalized micron-sized thermally conductive filler, 5-15 parts surface-functionalized nano-sized thermally conductive filler, 0.5-5 parts rheology modifier, 0.1-2 parts compatibilizer, and 0.1-2 parts antioxidant.

[0037] Further, the second thermally conductive blend comprises the following components by weight: 100 parts polyamide PA, 15-22 parts surface-functionalized micron-sized thermally conductive filler, 8-14 parts surface-functionalized nano-sized thermally conductive filler, 1-4 parts rheology modifier, 0.5-1.5 parts compatibilizer, and 0.5-1.5 parts antioxidant.

[0038] Furthermore, the second thermally conductive blend comprises the following components by weight: 100 parts polyamide PA, 18-20 parts surface-functionalized micron-sized thermally conductive filler, 10-12 parts surface-functionalized nano-sized thermally conductive filler, 2-3 parts rheology modifier, 1-1.2 parts compatibilizer, and 1-1.2 parts antioxidant.

[0039] In some preferred embodiments, the second thermally conductive blend is obtained by extrusion granulation of polyamide PA, surface-functionalized micron-sized thermally conductive filler, surface-functionalized nano-sized thermally conductive filler, rheology modifier, compatibilizer and antioxidant.

[0040] In some preferred embodiments, the preparation method of the surface-functionalized micron-sized thermally conductive filler includes: hydrolyzing an amino-containing silane coupling agent to form a silanol with a trihydroxy structure, and then blending the silanol with the micron-sized thermally conductive filler to obtain the surface-functionalized micron-sized thermally conductive filler.

[0041] Furthermore, the preparation method of the surface-functionalized micron-sized thermally conductive filler includes:

[0042] Step 1: Hydrolyze the amino-containing silane coupling agent to form a silanol with a trihydroxy structure; the hydrolysis temperature is 15-45℃ and the hydrolysis time is 10-60 min;

[0043] Step 2: Blend the silanol with a trihydroxy structure obtained by hydrolysis with micron-sized thermally conductive filler (alumina or magnesium oxide);

[0044] Step 3: The silanol with a trihydroxy structure reacts with the hydroxyl groups on the surface of the thermally conductive filler, and amino groups are introduced on the surface of the thermally conductive filler through silane hydrolysis-condensation. Specifically, the molar ratio of hydroxyl groups on the silanol surface to hydroxyl groups on the filler surface is 1:5-5:1, the solution pH is 2-5, the temperature is 30-90℃, and the reaction time is 1-12h.

[0045] Furthermore, the amino-containing silane coupling agent includes any one or a combination of two or more of KH540, KH550, and KH792, and is not limited thereto.

[0046] Furthermore, the micron-scale thermally conductive filler includes, but is not limited to, alumina and / or magnesium oxide.

[0047] In some preferred embodiments, the preparation method of the surface-functionalized nanoscale thermally conductive filler includes: hydrolyzing an epoxy-containing silane coupling agent to form a silanol with a trihydroxy structure, and then blending the silanol with the nanoscale thermally conductive filler to obtain the surface-functionalized nanoscale thermally conductive filler.

[0048] Furthermore, the preparation method of the surface-functionalized nanoscale thermally conductive filler includes:

[0049] Step 1: Hydrolyze the epoxy-containing silane coupling agent to form a silanol with a trihydroxy structure; the hydrolysis temperature is 15-45℃ and the hydrolysis time is 10-60 min;

[0050] Step 2: Blend the silanol with a trihydroxy structure obtained by hydrolysis with nanoscale thermally conductive fillers (aluminum nitride or boron nitride);

[0051] Step 3: The silanol with a trihydroxy structure reacts with the hydroxyl groups on the surface of the thermally conductive filler, and epoxy groups are introduced on the surface of the thermally conductive filler through silane hydrolysis-condensation; specifically, the molar ratio of hydroxyl groups on the silanol surface to hydroxyl groups on the filler surface is 1:5-5:1, the solution pH is 2-5, the temperature is 30-90℃, and the reaction time is 1-12h.

[0052] Furthermore, the epoxy-containing silane coupling agent includes any one or a combination of two or more of KH560, HD-M3133, and HD-E3133, and is not limited thereto.

[0053] Furthermore, the nanoscale thermally conductive filler includes, but is not limited to, aluminum nitride and / or boron nitride.

[0054] In some preferred embodiments, the preparation method of the surface-functionalized graphene oxide includes: first controlling the hydroxylation of graphene oxide, and then reacting it with cyanuric chloride and modifiers containing hydroxyl and epoxy groups, respectively, to obtain surface-functionalized graphene oxide.

[0055] Furthermore, the method for preparing the surface-functionalized graphene oxide includes:

[0056] Step 1: Control the hydroxylation of graphene oxide to retain hydroxyl groups on its surface; specifically, in a constant temperature chamber filled with a mixture of inert gas and nitrogen in a volume ratio of 1:1, the temperature is 250-300℃, and the graphene oxide treatment time is 10-60min.

[0057] Step 2: Utilizing the different reactivity of the three chlorine atoms in cyanuric chloride, the highly reactive chlorine reacts with the hydroxyl groups on the graphene surface, introducing cyanuric chloride groups containing active chlorine onto the graphene surface; specifically, the molar ratio of cyanuric chloride to hydroxyl groups in the graphene sheets is 1:5-5:1, the temperature is -10-25℃, and the reaction time is 3-24h.

[0058] Step 3: React graphene containing cyanuric chloride groups with a modifier containing hydroxyl and epoxy groups to introduce epoxy groups on its surface; specifically, the molar ratio of cyanuric chloride-containing graphene to hydroxyl groups of the modifier is 1:5-5:1, the temperature is -10-25℃, and the reaction time is 3-24h.

[0059] Furthermore, the modifier containing hydroxyl and epoxy groups includes, but is not limited to, hydroxyl epoxy resins.

[0060] In some preferred embodiments, the polyamide PA includes any one or a combination of two or more of PA6 (nylon 6), PA66 (polyhexamethylene adipamide), PA6-PA66 copolymer (nylon 6-polyhexamethylene adipamide copolymer), PA46 (polybutylene adipamide), PA1010 (polydecanoyl decanoyl diamine), PA1212 (polydodecanoyl dodecylamine), PA11 (polyundecyl lactam), and PA12 (polydodecyl lactam), and is not limited thereto.

[0061] In some preferred embodiments, the liquid crystal polymer (LCP) includes any one or a combination of two or more of the three types of LCPs: type I, type II, and type III, and is not limited thereto.

[0062] Specifically, the three types of LCP structures, Type I, Type II, and Type III, are as follows:

[0063]

[0064] In some preferred embodiments, the rheology modifier includes any one or a combination of two or more of petroleum resins, terpene resins, rosin esters, polyether-type rheology modifiers, polyurethane-type rheology modifiers, polyether-polyurethane associative rheology modifiers, and organobentonite-based rheology modifiers, and is not limited thereto.

[0065] In some preferred embodiments, the compatibilizer includes any one or more combinations of maleic anhydride-grafted nylon 6, glycidyl methacrylate-grafted nylon 6, glycidyl methacrylate-grafted polyethylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted ethylene-octene block copolymer, ethylene-maleic anhydride copolymer, and maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, and is not limited thereto.

[0066] In some preferred embodiments, the antioxidant includes, but is not limited to, any one or a combination of two or more of antioxidant 1010 (tetradecyl[3-3',5'-di-tert-butyl-4'-hydroxyphenyl]propionate), antioxidant DLTDP (dilauryl thiodipropionate), and antioxidant DSTDP (distearate thiodipropionate).

[0067] Another aspect of the present invention provides a method for preparing a modified BOPA film, comprising:

[0068] A modified BOPA film was prepared by three-layer co-extrusion using the aforementioned barrier blend, first thermally conductive blend and second thermally conductive blend.

[0069] The modified BOPA film comprises a surface layer formed by the barrier blend, an intermediate layer formed by the first thermally conductive blend, and an inner layer formed by the second thermally conductive blend.

[0070] In some preferred embodiments, the preparation method shown includes:

[0071] The barrier blend, the first thermally conductive blend, and the second thermally conductive blend are respectively melted and plasticized by an extrusion device and extruded through a T-die to obtain a melt; wherein, the melting temperatures of the barrier blend, the first thermally conductive blend, and the second thermally conductive blend are 240-280℃, 260-310℃, and 240-280℃, respectively, and the temperature of the T-die is 230-250℃;

[0072] A low-pressure air knife is used to attach the molten material to a cold roll to obtain a casting sheet; wherein the thickness of the casting sheet is 150-350μm and the temperature of the cold roll is 15-40℃.

[0073] Furthermore, the cast sheet is subjected to moisture conditioning, longitudinal and transverse bidirectional stretching, and heat setting treatment, and then the inner layer is subjected to corona treatment to obtain a modified BOPA film.

[0074] In some more specific embodiments, the method for preparing the modified BOPA film includes:

[0075] Step 1: Dry the barrier blend (the aforementioned "barrier blend"), thermally conductive blend 1 (the aforementioned "first thermally conductive blend"), and thermally conductive blend 2 (the aforementioned "second thermally conductive blend"), and control the moisture content to be below 500 ppm;

[0076] Step 2: The barrier blend, thermally conductive blend 1, and thermally conductive blend 2 are respectively passed through their respective screw extruders as the surface layer, intermediate layer, and inner layer of the functional modified BOPA film. They are melt-plasticized and extruded at melting temperatures of 240-280℃, 260-310℃, and 240-280℃, respectively, and flow out through a T-die with a die temperature of 230-250℃.

[0077] Step 3: Use a low-pressure air knife to attach the melt to a cold roll and cast it into a thick sheet, wherein the thickness of the cast sheet is 150-350 micrometers and the temperature of the cold roll is 15-40℃.

[0078] Step 4: Moisten the casting in a water bath at 35-75℃ for 1-3 minutes. After moistening, use an air knife to blow away the residual moisture on the surface of the casting and perform bidirectional stretching in both longitudinal and transverse directions. The stretching temperature is 170-210℃ and the stretching ratio is 2.5×2.5-3.5×3.5.

[0079] Step 5: The biaxially stretched film is heat-set at a temperature of 170-215℃, and the inner layer is corona-treated. Then it is wound up and slit to prepare a functional modified BOPA film with a thickness of 10-40 micrometers.

[0080] Another aspect of this invention provides a modified BOPA film prepared by the aforementioned method, wherein the modified BOPA film has a transverse (TD) tensile strength of 160-260 MPa, a longitudinal (MD) tensile strength of 200-300 MPa, a transverse elongation at break of 60%-160%, a longitudinal elongation at break (MD) of 40%-140%, a puncture force of 5-15 N, a thermal conductivity of 0.5-1.5 W / (m·K), and an oxygen permeability of 3-13 cm⁻¹. 3 / (m 2 ·d·atm).

[0081] Furthermore, the thickness of the modified BOPA film is 10-40 μm.

[0082] Specifically, the modified BOPA film is a three-layer co-extruded biaxially oriented polyamide film, consisting of a surface layer, a middle layer, and an inner layer from the outside to the inside, which are respectively obtained by extruding a barrier blend, a thermally conductive blend 1, and a thermally conductive blend 2.

[0083] In this invention, the inner layer of the modified BOPA film refers to the layer that is in close contact with electronic components during use; the outer layer refers to the layer exposed to air.

[0084] Another aspect of the present invention provides the use of the aforementioned modified BOPA film in the preparation of lithium-ion battery packaging.

[0085] This invention achieves functionally modified BOPA films with improved in-plane and vertical thermal conductivity and barrier properties through specific thermally conductive filler modification, formulation design, functional blend preparation, multilayer co-extrusion, and longitudinal and transverse biaxial stretching. This overcomes the performance bottleneck of conventional BOPA films, which suffer from poor thermal conductivity, especially in the vertical direction, thus fully meeting application requirements and greatly expanding its application areas.

[0086] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments. These embodiments are implemented on the premise of the technical solution of the invention, and provide detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0087] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0088] The present invention will be described in detail below through embodiments. In the following embodiments and comparative examples:

[0089] (1) Tensile properties (including tensile strength and elongation at break) were measured by a universal tensile testing machine (refer to national standard GB / T 1040.3);

[0090] (2) The puncture force was measured by a membrane puncture force tester (refer to national standard GB / T 37841-2019);

[0091] (3) The thermal conductivity was measured by a thermal conductivity meter (refer to ASTM C177).

[0092] (4) The oxygen permeability was measured by an oxygen permeability tester (refer to the American standard ASTM F1927);

[0093] (4) PA was purchased from Shenma Industry Co., Ltd., and MXD6, LCP, thermally conductive filler, graphene oxide and related additives were all obtained through commercial purchase.

[0094] The preparation methods for the surface-functionalized micron-sized thermally conductive fillers, surface-functionalized nano-sized thermally conductive fillers, and surface-functionalized graphene oxide used in the following embodiments are as follows:

[0095] 1. Methods for preparing surface-functionalized micron-sized thermally conductive fillers include:

[0096] Step 1: Hydrolyze KH540 to form silanol with a trihydroxy structure; the hydrolysis temperature is 30℃ and the hydrolysis time is 30min;

[0097] Step 2: Blend the silanol with a trihydroxy structure obtained from hydrolysis with alumina;

[0098] Step 3: The silanol with a trihydroxy structure reacts with the hydroxyl groups on the surface of the thermally conductive alumina filler, and amino groups are introduced on the surface of the thermally conductive filler through silane hydrolysis-condensation. Specifically, the molar ratio of hydroxyl groups on the silanol surface to hydroxyl groups on the filler surface is 1:2, the solution pH is 3, the temperature is 40℃, and the reaction time is 3h.

[0099] 2. Methods for preparing surface-functionalized nanoscale thermally conductive fillers include:

[0100] Step 1: Hydrolyze the epoxy-containing silane coupling agent HD-M3133 to form a silanol with a trihydroxy structure; the hydrolysis temperature is 25℃ and the hydrolysis time is 30min;

[0101] Step 2: Blend the silanol with a trihydroxy structure obtained by hydrolysis with aluminum nitride nanoscale thermally conductive filler;

[0102] Step 3: The silanol with a trihydroxy structure reacts with the hydroxyl groups on the surface of the thermally conductive filler, and epoxy groups are introduced on the surface of the thermally conductive filler through silane hydrolysis-condensation; specifically, the molar ratio of hydroxyl groups on the silanol surface to hydroxyl groups on the filler surface is 1:3, the solution pH is 4, the temperature is 45℃, and the reaction time is 5h.

[0103] 3. Methods for preparing surface-functionalized graphene oxide include:

[0104] Step 1: Control the hydroxylation of graphene oxide to retain hydroxyl groups on its surface; specifically, in a constant temperature chamber filled with a mixture of inert gas and nitrogen in a volume ratio of 1:1, the temperature is 260℃, and the graphene oxide treatment time is 30min.

[0105] Step 2: Utilizing the different reactivity of the three chlorine atoms in cyanuric chloride, the highly reactive chlorine reacts with the hydroxyl groups on the graphene surface, introducing cyanuric chloride groups containing active chlorine onto the graphene surface; specifically, the molar ratio of cyanuric chloride to hydroxyl groups in the graphene sheets is 1:3, the temperature is 10℃, and the reaction time is 8h.

[0106] Step 3: React graphene containing cyanuric chloride groups with hydroxyl epoxy resin, a modifier containing hydroxyl and epoxy groups, to introduce epoxy groups on its surface; specifically, the molar ratio of cyanuric chloride-containing graphene to hydroxyl modifier is 1:3, the temperature is 10℃, and the reaction time is 5h.

[0107] Example 1

[0108] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0109] The surface layer (barrier blend) includes: matrix resin (PA: 20 parts by weight and MXD6: 80 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 20 parts by weight, surface-functionalized nano-sized thermally conductive filler: 12 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0110] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 12 parts by weight, liquid crystal polymer (LCP): 20 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0111] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 20 parts by weight, surface-functionalized nano-sized thermal conductive filler: 12 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0112] In this embodiment, PA is PA6; LCP is type I LCP; rheology modifier is petroleum resin; compatibilizer is maleic anhydride-grafted nylon 6; and antioxidant is antioxidant 1010.

[0113] Example 2

[0114] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0115] The surface layer (barrier blend) includes: matrix resin (PA: 22 parts by weight and MXD6: 78 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 19 parts by weight, surface-functionalized nano-sized thermally conductive filler: 11 parts by weight, rheology modifier: 2.5 parts by weight, compatibilizer: 1.1 parts by weight, antioxidant: 1.1 parts by weight.

[0116] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 11 parts by weight, liquid crystal polymer (LCP): 18 parts by weight, rheology modifier: 2.6 parts by weight, compatibilizer: 1.1 parts by weight, antioxidant: 1.1 parts by weight.

[0117] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 19 parts by weight, surface-functionalized nano-sized thermal conductive filler: 11 parts by weight, rheology modifier: 2.6 parts by weight, compatibilizer: 1.1 parts by weight, antioxidant: 1.1 parts by weight.

[0118] In this embodiment, PA is PA6; LCP is type I LCP; rheology modifier is petroleum resin; compatibilizer is maleic anhydride-grafted nylon 6; and antioxidant is antioxidant 1010.

[0119] Example 3

[0120] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0121] The surface layer (barrier blend) includes: matrix resin (PA: 25 parts by weight and MXD6: 75 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 18 parts by weight, surface-functionalized nano-sized thermally conductive filler: 10 parts by weight, rheology modifier: 2 parts by weight, compatibilizer: 1 part by weight, antioxidant: 1 part by weight.

[0122] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 10 parts by weight, liquid crystal polymer (LCP): 16 parts by weight, rheology modifier: 2 parts by weight, compatibilizer: 1 part by weight, antioxidant: 1 part by weight.

[0123] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 18 parts by weight, surface-functionalized nano-sized thermal conductive filler: 10 parts by weight, rheology modifier: 2 parts by weight, compatibilizer: 1 part by weight, antioxidant: 1 part by weight.

[0124] In this embodiment, PA is PA6; LCP is type I LCP; rheology modifier is petroleum resin; compatibilizer is maleic anhydride-grafted nylon 6; and antioxidant is antioxidant 1010.

[0125] Example 4

[0126] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0127] The surface layer (barrier blend) includes: matrix resin (PA: 15 parts by weight and MXD6: 85 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 22 parts by weight, surface-functionalized nano-sized thermally conductive filler: 14 parts by weight, rheology modifier: 4 parts by weight, compatibilizer: 1.5 parts by weight, antioxidant: 1.5 parts by weight.

[0128] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 13 parts by weight, liquid crystal polymer (LCP): 22 parts by weight, rheology modifier: 4 parts by weight, compatibilizer: 1.5 parts by weight, antioxidant: 1.5 parts by weight.

[0129] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 22 parts by weight, surface-functionalized nano-sized thermal conductive filler: 14 parts by weight, rheology modifier: 4 parts by weight, compatibilizer: 1.5 parts by weight, antioxidant: 1.5 parts by weight.

[0130] In this embodiment, PA is PA6; LCP is type II LCP; rheology modifier is petroleum resin; compatibilizer is glycidyl methacrylate-grafted nylon 6; and antioxidant is antioxidant 1010.

[0131] Example 5

[0132] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0133] The surface layer (barrier blend) includes: matrix resin (PA: 30 parts by weight and MXD6: 70 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 15 parts by weight, surface-functionalized nano-sized thermally conductive filler: 8 parts by weight, rheology modifier: 1 part by weight, compatibilizer: 0.5 parts by weight, antioxidant: 0.5 parts by weight.

[0134] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 8 parts by weight, liquid crystal polymer (LCP): 12 parts by weight, rheology modifier: 1 part by weight, compatibilizer: 0.5 parts by weight, antioxidant: 0.5 parts by weight.

[0135] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 15 parts by weight, surface-functionalized nano-sized thermal conductive filler: 8 parts by weight, rheology modifier: 1 part by weight, compatibilizer: 0.5 parts by weight, antioxidant: 0.5 parts by weight.

[0136] In this embodiment, PA is PA6; LCP is type III LCP; rheology modifier is petroleum resin; compatibilizer is glycidyl methacrylate-grafted nylon 6; and antioxidant is antioxidant 1010.

[0137] Example 6

[0138] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0139] The surface layer (barrier blend) includes: matrix resin (PA: 40 parts by weight and MXD6: 60 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 10 parts by weight, surface-functionalized nano-sized thermally conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0140] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 5 parts by weight, liquid crystal polymer (LCP): 10 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0141] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 10 parts by weight, surface-functionalized nano-sized thermal conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0142] In this embodiment, PA is PA46 (poly(dibutyl adipamide)); LCP is type II LCP; rheology modifier is terpene resin; compatibilizer is glycidyl methacrylate-grafted polyethylene; and antioxidant is DLTDP.

[0143] Example 7

[0144] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0145] The surface layer (barrier blend) includes: matrix resin (PA: 10 parts by weight and MXD6: 90 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 25 parts by weight, surface-functionalized nano-sized thermally conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0146] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 15 parts by weight, liquid crystal polymer (LCP): 25 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0147] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 25 parts by weight, surface-functionalized nano-sized thermal conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0148] In this embodiment, PA is PA1010; LCP is type III LCP; rheology modifier is rosin ester; compatibilizer is maleic anhydride-grafted polypropylene; and antioxidant is antioxidant DLTDP.

[0149] Example 8

[0150] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0151] The surface layer (barrier blend) includes: matrix resin (PA: 10 parts by weight and MXD6: 90 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 25 parts by weight, surface-functionalized nano-sized thermally conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0152] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 5 parts by weight, liquid crystal polymer (LCP): 10 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0153] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 25 parts by weight, surface-functionalized nano-sized thermal conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0154] In this embodiment, PA is PA1212; LCP is type I LCP; rheology modifier is polyether rheology modifier; compatibilizer is acrylic acid grafted ethylene-octene block copolymer; antioxidant is antioxidant DSTDP.

[0155] Example 9

[0156] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0157] The surface layer (barrier blend) includes: matrix resin (PA: 40 parts by weight and MXD6: 60 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 10 parts by weight, surface-functionalized nano-sized thermally conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0158] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 15 parts by weight, liquid crystal polymer (LCP): 25 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0159] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 10 parts by weight, surface-functionalized nano-sized thermal conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0160] In this embodiment, PA is PA11; LCP is type I LCP; rheology modifier is polyurethane type rheology modifier; compatibilizer is ethylene maleic anhydride copolymer; and antioxidant is antioxidant DSTDP.

[0161] Example 10

[0162] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0163] The surface layer (barrier blend) includes: matrix resin (PA: 40 parts by weight and MXD6: 60 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 10 parts by weight, surface-functionalized nano-sized thermally conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0164] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 15 parts by weight, liquid crystal polymer (LCP): 25 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0165] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 10 parts by weight, surface-functionalized nano-sized thermal conductive filler: 5 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0166] In this embodiment, PA is PA12; LCP is a blend of type I and type II LCP; rheology modifier is a polyether polyurethane associative rheology modifier; compatibilizer is maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer; and antioxidant is a blend of antioxidant 1010 and antioxidant DLTDP.

[0167] Example 11

[0168] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0169] The surface layer (barrier blend) includes: matrix resin (PA: 10 parts by weight and MXD6: 90 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 25 parts by weight, surface-functionalized nano-sized thermally conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0170] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 12 parts by weight, liquid crystal polymer (LCP): 20 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0171] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 25 parts by weight, surface-functionalized nano-sized thermal conductive filler: 15 parts by weight, rheology modifier: 5 parts by weight, compatibilizer: 2 parts by weight, antioxidant: 2 parts by weight.

[0172] In this embodiment, PA is a blend of PA66 and PA6-PA66 copolymer; LCP is a blend of type II and type III LCP; rheology modifier is an organobentonite rheology modifier; compatibilizer is a blend of maleic anhydride-grafted nylon 6 and glycidyl methacrylate-grafted nylon 6; antioxidant is a blend of antioxidant 1010 and antioxidant DSTDP.

[0173] Example 12

[0174] This embodiment illustrates the preparation of a functionally modified BOPA film using the functional blends and methods of the present invention.

[0175] The surface layer (barrier blend) includes: matrix resin (PA: 20 parts by weight and MXD6: 80 parts by weight); based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermally conductive filler: 20 parts by weight, surface-functionalized nano-sized thermally conductive filler: 12 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0176] The intermediate layer (thermally conductive blend 1) comprises: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized graphene oxide (MGO): 5 parts by weight, liquid crystal polymer (LCP): 10 parts by weight, rheology modifier: 0.5 parts by weight, compatibilizer: 0.1 parts by weight, antioxidant: 0.1 parts by weight.

[0177] The inner layer (thermal conductive blend 2) includes: matrix resin PA; based on 100 parts by weight of matrix resin, surface-functionalized micron-sized thermal conductive filler: 20 parts by weight, surface-functionalized nano-sized thermal conductive filler: 12 parts by weight, rheology modifier: 3 parts by weight, compatibilizer: 1.2 parts by weight, antioxidant: 1.2 parts by weight.

[0178] In this embodiment, PA is a blend of PA6, PA66, and PA6-PA66 copolymer; LCP is a blend of type I and type III LCP; rheology modifier is a blend of petroleum resin and terpene resin; compatibilizer is a blend of maleic anhydride-grafted nylon 6 and acrylic acid-grafted ethylene-octene block copolymer; and antioxidant is a blend of antioxidant DLTDP and antioxidant DSTDP.

[0179] The method for preparing the modified BOPA film in the above embodiments of the present invention includes the following steps:

[0180] Step 1: Dry the barrier blend, thermally conductive blend 1, and thermally conductive blend 2, controlling the moisture content to be below 500 ppm;

[0181] Step 2: The barrier blend, thermally conductive blend 1, and thermally conductive blend 2 are respectively extruded through their respective screw extruders as the surface layer, intermediate layer, and inner layer of the functional modified BOPA film. The extrusion is performed by melt plasticizing at melting temperatures of T1 (240-280℃), T2 (260-310℃), and T3 (240-280℃), and then flows out through a T-die at a die temperature of T4 (230-250℃).

[0182] Step 3: Use a low-pressure air knife to attach the melt to a cold roll and cast it into a thick sheet, wherein the thickness of the cast sheet is Thickness 1 (150-350 micrometers) and the temperature of the cold roll is T5 (15-40℃).

[0183] Step 4: Humidify the casting in a water bath at temperature T6 (35-75℃) for a certain time t (1-3 minutes). After humidification, use an air knife to blow away the residual moisture on the surface of the casting and perform longitudinal and transverse bidirectional stretching at a temperature of T7 (170-210℃) and a stretching ratio of DR (2.5×2.5-3.5×3.5).

[0184] Step 5: The biaxially stretched film is heat-set at T8 (170-215℃), and the inner layer is corona-treated. Then it is wound up and slit to prepare a functional modified BOPA film with a thickness of Thickness 2 (10-40 micrometers).

[0185] The process parameters for each embodiment are shown in Tables 1 and 2:

[0186] Table 1. Process parameters for preparing the thin films in the examples.

[0187]

[0188]

[0189] Table 2. Process parameters for preparing the thin films in the examples.

[0190] name <![CDATA[Thickness1 (micrometers)]]> <![CDATA[Thickness2 (micrometers)]]> T(min) DR Example 1 220 20 2.1 3.5×3.5 Example 2 200 18 2.0 3.5×3.5 Example 3 232 22 1.8 3.5×3.5 Example 4 254 25 2.3 2.8×2.8 Example 5 280 28 1.9 3.0×3.0 Example 6 350 40 1 3.5×3.5 Example 7 150 32 3 2.5×2.5 Example 8 150 10 2.2 3.5×3.5 Example 9 346 35 1.7 2.7×2.7 Example 10 290 27 1.5 2.9×2.9 Example 11 320 30 2.5 3.0×3.0 Example 12 180 15 2.7 3.3×3.3

[0191] Comparative Example 1

[0192] The method is the same as in Example 6, except that LCP is not added.

[0193] Comparative Example 2

[0194] The method is the same as in Example 6, except that MGO is not added.

[0195] Comparative Example 3

[0196] The method is the same as in Example 6, except that MGO is replaced with GO.

[0197] Comparative Example 4

[0198] The method is the same as in Example 6, except that the surface-functionalized micro / nano-scale thermally conductive filler is replaced with an unfunctionalized micro / nano-scale thermally conductive filler.

[0199] The performance of each embodiment and comparative example is shown in Table 3:

[0200] Table 3. Performance of the thin films in each embodiment and comparative example.

[0201]

[0202] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0203] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A composition for preparing a modified BOPA film, characterized in that Comprise: Barrier blend, first thermal conductive blend and second thermal conductive blend; Wherein, the barrier blend comprises: base resin 100 parts, surface functionalized micron-sized thermal conductive filler 10-25 parts, surface functionalized nanometer-sized thermal conductive filler 5-15 parts, rheological aid 0.5-5 parts, compatibilizer 0.1-2 parts and antioxidant 0.1-2 parts, the base resin comprises poly-m-xylylene adipamide 60-90 parts, and the rest is polyamide PA; The first thermal conductive blend comprises: polyamide PA 100 parts, surface functionalized graphene oxide 5-15 parts, liquid crystal polymer 10-25 parts, rheological aid 0.5-5 parts, compatibilizer 0.1-2 parts and antioxidant 0.1-2 parts; The second thermal conductive blend comprises: polyamide PA 100 parts, surface functionalized micron-sized thermal conductive filler 10-25 parts, surface functionalized nanometer-sized thermal conductive filler 5-15 parts, rheological aid 0.5-5 parts, compatibilizer 0.1-2 parts and antioxidant 0.1-2 parts; The preparation method of the surface functionalized micron-sized thermal conductive filler comprises: hydrolyzing amino-containing silane coupling agent to form silanol with trihydroxy structure, and then blending and reacting the silanol with micron-sized thermal conductive filler to obtain the surface functionalized micron-sized thermal conductive filler; wherein the amino-containing silane coupling agent comprises any one or a combination of two or more of KH540, KH550 and KH792; and the micron-sized thermal conductive filler comprises alumina and / or magnesium oxide; The preparation method of the surface functionalized nanometer-sized thermal conductive filler comprises: hydrolyzing epoxy-containing silane coupling agent to form silanol with trihydroxy structure, and then blending and reacting the silanol with nanometer-sized thermal conductive filler to obtain the surface functionalized nanometer-sized thermal conductive filler; wherein the epoxy-containing silane coupling agent is KH560; and the nanometer-sized thermal conductive filler comprises aluminum nitride and / or boron nitride; The preparation method of the surface functionalized graphene oxide comprises: first, performing hydroxyl group control treatment on graphene, and then respectively reacting with cyanuric chloride and a modifier containing hydroxyl and epoxy groups to obtain the surface functionalized graphene oxide; wherein the modifier containing hydroxyl and epoxy groups comprises hydroxyl epoxy resin.

2. The composition of claim 1, wherein, The barrier blend comprises the following components by weight parts: base resin 100 parts, surface functionalized micron-sized thermal conductive filler 15-22 parts, surface functionalized nanometer-sized thermal conductive filler 8-14 parts, rheological aid 1-4 parts, compatibilizer 0.5-1.5 parts and antioxidant 0.5-1.5 parts, and the base resin comprises poly-m-xylylene adipamide 70-85 parts, and the rest is polyamide PA.

3. The composition of claim 2, wherein, The barrier blend comprises the following components by weight parts: base resin 100 parts, surface functionalized micron-sized thermal conductive filler 18-20 parts, surface functionalized nanometer-sized thermal conductive filler 10-12 parts, rheological aid 2-3 parts, compatibilizer 1-1.2 parts and antioxidant 1-1.2 parts, and the base resin comprises poly-m-xylylene adipamide 75-80 parts, and the rest is polyamide PA.

4. The composition of claim 1, wherein, The first heat-conductive blend comprises the following components by weight parts: polyamide PA 100 parts, surface-functionalized graphene oxide 8-13 parts, liquid crystal polymer 12-22 parts, rheological agent 1-4 parts, compatibilizer 0.5-1.5 parts, and antioxidant 0.5-1.5 parts.

5. The composition of claim 4, wherein, The first heat-conductive blend comprises the following components by weight parts: polyamide PA 100 parts, surface-functionalized graphene oxide 10-12 parts, liquid crystal polymer 16-20 parts, rheological agent 2-3 parts, compatibilizer 1-1.2 parts, and antioxidant 1-1.2 parts.

6. The composition of claim 1, wherein, The second heat-conductive blend comprises the following components by weight parts: polyamide PA 100 parts, surface-functionalized micro-scale heat-conductive filler 15-22 parts, surface-functionalized nano-scale heat-conductive filler 8-14 parts, rheological agent 1-4 parts, compatibilizer 0.5-1.5 parts, and antioxidant 0.5-1.5 parts.

7. The composition of claim 6, wherein, The second heat-conductive blend comprises the following components by weight parts: polyamide PA 100 parts, surface-functionalized micro-scale heat-conductive filler 18-20 parts, surface-functionalized nano-scale heat-conductive filler 10-12 parts, rheological agent 2-3 parts, compatibilizer 1-1.2 parts, and antioxidant 1-1.2 parts.

8. The composition of claim 1, wherein: The polyamide PA comprises any one of PA6, PA66, PA6-PA66 copolymer, PA46, PA1010, PA1212, PA11, PA12, or a combination of two or more thereof.

9. The composition of claim 1, wherein: The liquid crystal polymer LCP comprises any one of type I, type II, and type III LCP, or a combination of two or more thereof.

10. The composition of claim 1, wherein: The rheological agent comprises any one of petroleum resin, terpene resin, rosin ester, polyether-type rheological agent, polyurethane-type rheological agent, and organic bentonite-type rheological agent, or a combination of two or more thereof.

11. The composition of claim 1, wherein: The compatibilizer comprises any one of maleic anhydride grafted nylon 6, glycidyl methacrylate grafted nylon 6, glycidyl methacrylate grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted ethylene-octene block copolymer, ethylene-maleic anhydride copolymer, and maleic anhydride grafted styrene-ethylene-butylene-styrene copolymer, or a combination of two or more thereof.

12. The composition of claim 1, wherein: The antioxidant comprises any one of antioxidant 1010, antioxidant DLTDP, and antioxidant DSTDP, or a combination of two or more thereof.

13. A method of making a modified BOPA film, characterized in that Comprising: The modified BOPA film is prepared by three-layer co-extrusion of the barrier blend, the first heat-conductive blend, and the second heat-conductive blend according to any one of claims 1-12. The modified BOPA film comprises a surface layer formed by the barrier blend, a middle layer formed by the first heat-conductive blend, and an inner layer formed by the second heat-conductive blend.

14. The method of claim 13, wherein Comprising: The barrier blend, the first heat-conducting blend and the second heat-conducting blend are respectively melt-plasticized and extruded through an extrusion device and a T-shaped die to obtain a melt; wherein the melt temperatures of the barrier blend, the first heat-conducting blend and the second heat-conducting blend are respectively 240-280℃, 260-310℃ and 240-280℃, and the temperature of the T-shaped die is 230-250℃; The melt is attached to a cold roller by a low-pressure air knife to obtain a cast sheet; wherein the thickness of the cast sheet is 150-350μm, and the temperature of the cold roller is 15-40℃; The cast sheet is subjected to humidity adjustment, longitudinal and lateral stretching, heat setting, and the inner layer is subjected to corona treatment to obtain the modified BOPA film.

15. Modified BOPA film produced by the production process according to claim 13 or 14, characterized in that: The modified BOPA film has a transverse tensile strength of 160-260 MPa, a longitudinal tensile strength of 200-300 MPa, a transverse elongation at break of 60%-160%, a longitudinal elongation at break of 40%-140%, a puncture force of 5-15 N, a thermal conductivity of 0.5-1.5 W / (m K), and an oxygen transmission rate of 3-13 cm 3 / (m 2 d atm); and a thickness of 10-40 μm.

16. Use of the modified BOPA film of claim 15 in the preparation of lithium ion battery packaging.

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