Composite with high thermal conductivity and method for producing the composite

Abstract

To provide a composite article suitable for thermal management. The composite article may include a composite including an organic polymer and ceramic particles including hexagonal boron nitride (hBN) particles distributed throughout the organic polymer, the amount of hBN particles ranging from 20% to 40% by volume based on the total volume of the composite, and the composite having an in-plane thermal conductivity of at least 10 W / mK. The hBN particles in the composite may have a March-Dorus orientation parameter η of at least 50%.

Description

[Technical Field]

[0001] The present disclosure relates to an organic polymer and a hexagonal nitride nanoparticle that is dispersed throughout the organic polymer with a high degree of orientation. Composite containing ceramic particles including boron (hBN) particles, and method for making the composite Regarding. [Background technology]

[0002] Thermally conductive polymer composites improve the performance of the device by dissipating heat to avoid overheating. It is suitable for use as a heat sink for electrical devices, as it can significantly reduce the temperature and extend the life of the device. Thermally conductive polymer composites play an important role in various industries. Typical industries that play a major role include consumer electronics (e.g., mobile phones, tablets), Telecommunications infrastructure (e.g., cell towers), LED lighting, hybrid, and and electric vehicles (power modules), data centers (server boards, switches, monitoring modules and power supplies), and solar cells.

[0003] There is a need for greater variety and efficiency of materials suitable for thermal management. [Brief explanation of the drawings]

[0004] The present disclosure may be better understood and its numerous features may be better understood by reference to the accompanying drawings. and advantages will be apparent to those skilled in the art.

[0005] [Figure 1A] FIG. 1A is a diagram showing platelet-type hBN particles, according to one embodiment. [Figure 1B] FIG. 1B includes a line drawing showing a cross-sectional side view of a composite having in-plane oriented hBN grains, according to one embodiment. [Figure 1C]FIG. 1C includes a line drawing showing a cross-sectional side view of a composite having hBN particles oriented in the through-plane direction, according to one embodiment. [Figure 2A] FIG. 2A includes a graph showing an X-ray spectrum of a composite including in-plane oriented hBN particles, according to one embodiment. [Figure 2B] Figure 2B is a graph showing the relationship between r and the orientation parameter η according to the March-Dorus method. [Figure 3] FIG. 3 includes IR spectra of hBN particles before and after exfoliation and siliconization, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] As used herein, "comprises" and "comprising" "includes," "including," "has," "having" The term "(s)" or any other variation thereof is intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features does not necessarily represent that list. The present invention is not limited to these features only, and does not include any process not expressly listed or It may include other features specific to a method, article, or device.

[0007] As used herein, unless clearly stated to the contrary, "or" is an inclusive term. For example, condition A or B can be any of the following: is satisfied by one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true is (or exists), and both A and B are true (or exist).

[0008] Also, the use of "a" or "an" refers to the elements and This is used merely for convenience and to provide a general overview of the scope of the present invention. This statement is to be read to include one or at least one. and the singular should also be used in conjunction with the plural unless it is clear that this is not meant to be the case. Also includes.

[0009] The present disclosure provides a method for producing a polymeric composite of organic polymers and hexagonal boron nitride distributed throughout the organic polymer. and ceramic particles comprising hBN particles. The amount of the polymer may be in the range of 20% to 40% by volume based on the total volume of the composite, and the ceramic The amount of the particles may be 50% by volume or less based on the total volume of the composite, and the composite may have at least The composite article may include an in-plane thermal conductivity of 10 W / mK.

[0010] As used herein, the term hBN particles refers to particles, unless otherwise indicated, as shown in FIG. As shown in FIG. 1A, the average aspect ratio of the length to thickness (L / T) is at least 5. This relates to platelet-shaped hBN particles.

[0011] As further used herein, the term "in-plane" refers to the plane of the composite with respect to the x and y directions. FIG. 1B shows that the hBN particles (12) can be oriented in the x and y directions of the composite (as used herein). 1 shows a cross section (10) of the composite (also referred to as aligned), which is interchangeably referred to herein as In contrast, Figure 1C shows that the hBN grains (12) are aligned in the z direction. 1 shows an embodiment of a composite slice, as used herein in the "through-plane" or thickness direction of the composite. are also called interchangeably.

[0012] In one embodiment, the composite of the present disclosure comprises ceramic particles comprising hBN and an organic polymer. preparing a mixture comprising: applying a layer of the mixture to a mold or support; and performing an alignment procedure of the molecules and solidifying the organic polymer to form a composite and / or and curing.

[0013] In one embodiment, the alignment procedure involves applying pressure perpendicular to the in-plane directions (x- and y-directions) of the mixture layers. In certain embodiments, the pressure may include applying a layer of the material to a 12 inch by 12 inch metal plate. and applying pressure to the layer using a second metal plate of the same size. The weight applied to the second metal plate is at least 40,000 lbs, or less. 50,000 lbs, or at least 60,000 lbs, or at least 70,0 In a further embodiment, the weight on the second plate can be 150,000 lbs. It may be less than bs.

[0014] In one embodiment, the method includes surface functionalizing the hBN particles prior to preparing the mixture. The surface functionalization may include exfoliating the activated hBN particles to form activated hBN particles. and activating the hBN particles, and treating the activated hBN particles with an organic compound.

[0015] In one embodiment, activating includes introducing OH groups onto the outer surface of the hBN particles. obtain.

[0016] In certain embodiments, exfoliation involves cutting or peeling off the hBN platelet particles to reduce the surface area of ​​the hBN particles. The activation of hBN particles can be a mechanical process that can increase the The method involves treating the particles with an alkaline fluid, which covalently bonds the hBN particles to the OH groups may be introduced onto the surface of the carbon nanotube.

[0017] In certain embodiments, stripping and activation can occur simultaneously. The exfoliation of hBN particles was achieved by ball milling using aqueous sodium hydroxide as the liquid medium. may include:

[0018] The exfoliated and activated hBN particles can be further surface functionalized with organic compounds. In certain embodiments, the organic compound is a polysiloxane or polysilane containing silicon hydride groups, or a silane compound, or any combination thereof.

[0019] In certain embodiments, chemically reacting a silane compound with hBN particles results in boron In a non-limiting example, the boron catalyst may be a triborohydride. It may include (pentafluorophenyl)borane.

[0020] After exfoliation and activation of hBN particles, the interaction between the introduced OH groups and selected organic compounds was investigated. By chemically reacting with the organic compound, it is possible to covalently bond the organic compound to the surface of the hBN particle. This is also referred to herein as grafting.

[0021] In certain embodiments, the grafting of the surface of the hBN particles is carried out using silicone as the organic compound. In certain embodiments, the conjugate may be a polysiloxane containing an anhydride group. Surface-functionalized hBN particles grafted with siloxane and organic polymers. and a silicone polymer having molecules distributed therein.

[0022] Surface functionalization may not be limited to polysiloxane grafting, and may also be used to treat exfoliated hBN particles. Any other monomer, oligomer, or polymer capable of reacting with the introduced OH group Without being bound by theory, the grafted surface of the hBN particles may include Increased compatibility of the polymer with the organic polymer matrix, thereby resulting in lower processing viscosity This allows for easier alignment and improved uniformity of the curing.

[0023] In some embodiments, the organic polymer of the composite is a thermoplastic polymer or a thermoset polymer. It can be a mar.

[0024] In certain embodiments, the organic polymer can be a polymerizable polymer that includes functional groups. In certain embodiments, curing of the polymerizable monomer is required after and / or during compression molding. This may be the case.

[0025] Non-limiting examples of polymerizable polymers include silicone polymers and acrylate polymers. , or an epoxy polymer.

[0026] In certain embodiments, the polymerizable polymer is a silicone polymer containing vinyl groups. In a non-limiting embodiment, the vinyl-containing silicone polymer is crosslinked with a crosslinking agent. In one embodiment, the crosslinking agent for the silicone polymer containing vinyl groups can be The weight percentage ratio to the total may be 0.5-5, or 1-3, or 1-2.

[0027] In certain embodiments, the silicone polymer has a molecular weight of at least 10,000 g / mol and at least At least 100,000 g / mol, at least 200,000 g / mol, at least 4 00,000 g / mol, or at least 700,000 g / mol In another particular embodiment, the molecular weight of the silicone polymer is 1,000,000 g / mol or less, or 800,000 g / mol or less, or 700,000 g / mol or less, or 5 00,000 g / mol or less, or 300,000 g / mol or less, or 100,000 It may be less than g / mol.

[0028] In another particular embodiment, the organic polymer can be a thermoplastic polymer. Non-limiting examples of polymers include polyethylene, polypropylene, polystyrene, polyurethane, Polyacrylate, polyester, polycarbonate, polyimide, polybutylene terephthalate Poly(vinyl methacrylate) (PBT), Poly(methyl methacrylate) (PMMA), Poly(ethylene terephthalate) Polyethylene terephthalate (PET), polyamide, liquid crystal polymer (LCP), polyacrylonitrile (PAN ), Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK) , polysulfone, polyethersulfone, polyphenylene oxide (PPO), polyether Thermoplastic elastomers (TPE, olefin or styrene), polyfluoride Fluoropolymers such as polyvinylidene fluoride (PVDF), perfluoroalkoxyalkanes ( PFA), fluorinated ethylene propylene (FEP), or ethylene tetrafluoroethylene ethylene (ETFE), or any copolymer thereof, or any combination thereof It may include.

[0029] In certain embodiments, the composite comprises surface-functionalized hBN particles grafted with polysiloxane. and, as the organic polymer, a silicone polymer in which hBN particles are distributed.

[0030] In another specific embodiment, the hBN particles are surface functionalized via fluorine surface functionalization. Examples of fluorine surface functionalization include CF4, or C This may include plasma treatment with HF3, SF6, or C2F6.

[0031] In another embodiment, the organic polymer can be an epoxy polymer and the hBN particles are epoxidized. The epoxy compound may be surface-functionalized with an epoxy group, an amine group, or a hydroxyl group. Non-limiting examples of introducing glycidyl methacrylate include plasma treatment with glycidyl methacrylate or allyl glycidyl methacrylate. An example of amine functionalization is plasma treatment with an allyl ether. Or it may include a plasma treatment with 3-(aminopropyl)triethoxysilane.

[0032] In a further embodiment, the organic polymer can be polyethylene and the hBN particles have fluorine surface functional groups. The polymer may be subjected to polymerization or silane functionalization.

[0033] In yet another embodiment, the organic polymer is a thermoplastic polyurethane (TPU) or polybutylene. The polymer may be polybutadiene terephthalate (PBT), and the hBN particles may be bonded to an epoxy compound, an amine, or In certain further embodiments, PBT can also be functionalized with hydroxyl groups. treatment, air plasma treatment, treatment with boric acid / urea in combination with heat treatment, or heat treatment It can be surface functionalized by treatment with combined boric acid / melamine.

[0034] In certain embodiments, the composites of the present disclosure have an in-plane thermal conductivity of at least 10 W / mK. and the corresponding amount of hBN particles is 39% by volume or less, or 38% by volume or less, or 37% by volume or less. or less, or 36% by volume or less, or 35% by volume or less, or 34% by volume or less, or 33% by volume or less, or 32% by volume or less, or 31% by volume or less, or 30% by volume or less, or 29% by volume or less, or 28% by volume or less, or 25% by volume or less.

[0035] In certain embodiments, a majority of the ceramic particles contained within the composite, e.g., at least 90% by volume, or at least 92% by volume, based on the total volume of the composite particles; or At least 94% by volume, or at least 96% by volume, or at least 98% by volume, or At least 99% by volume may be hBN particles. In certain embodiments, the ceramic particles The particles can consist essentially of hBN particles, and by consisting essentially of hBN particles, it is meant that the particles In the specification, this means that the ceramic particles are not hBN particles and have 0.5% or less by volume. do.

[0036] The orientation of the hBN particles within the complex (also referred to herein as the exchangeable alignment of the hBN particles) (This is done by X-ray diffraction and analyzing the X-ray spectrum according to the March-Doras method. can be measured by the March-Doras orientation parameter (see detailed explanation in the Examples). η is a suitable quantitative expression to characterize the degree of alignment of hBN particles dispersed within the composite. It has been found that good alignment can be achieved in the present disclosure by aligning at least 50% of the sequences. The Tsidorath orientation parameter η is considered to be the hBN orientation parameter. the March-Dauras orientation parameter of the particles is at least 52%, or at least 54%, Or it may be at least 56%, or at least 58%, or at least 60%.

[0037] As further demonstrated in the examples, surprisingly, h before functionalization with organic compounds A specific combination of mechanical exfoliation and chemical treatment of BN particles results in hBN concentrations of less than 40% by volume. It has been found that this can provide a thermal conductivity of at least 10 W / mK at 2000K.

[0038] In one embodiment, the hBN particles have at least 5, or at least 7, or at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60, or at least 70, or at least 80, or at least 90, or at least 100, or at least 110, or at least 120 hBN grains In certain embodiments, the asymmetric crystals may have an average aspect ratio of length (L) to thickness (T). The aspect ratio is 200 or less, or 120 or less, or 80 or less, or 50 or less, or 30 or less , or may be 15 or less.

[0039] In another embodiment, the hBN particles are at least 1 micron, or at least 3 microns. or at least 5 microns, or at least 10 microns, or at least 15 microns ron, or at least 20 microns, or at least 25 microns, or at least 30 In a further embodiment, the hBN particles may have an average particle size (D50) of 100 microns. microns or less, or 50 microns or less, or 45 microns or less, or 40 microns or less, Or 35 microns or less, or 30 microns or less, or 25 microns or less, or 20 microns The particles may have an average particle size of 10 microns or less, or 10 microns or less, or 5 microns or less.

[0040] In some embodiments, the hBN particles of the composite have a multimodal particle distribution, e.g., bimodal or trimodal. In certain embodiments, the particle distribution may be a bimodal particle distribution (PSD). do.

[0041] In one embodiment, the particle size distribution of the hBN particles has a first peak and a second peak having a first peak maximum. and a second peak having a second peak maximum, The intensity ratio of the peaks at the peaks is at least 1.5:1, or at least 2:1, or at least 2 In another embodiment, the first peak maximum pair may be 0.5:1, or at least 3.0:1. the intensity ratio of the second peak maximum is 10:1 or less, or 7:1 or less, or 5:1 or less, or It may be 4:1 or less, or 3.5:1 or less, or 3.0:1 or less.

[0042] In another embodiment, the hBN particle size distribution is The distance is at least 20 microns, or at least 25 microns, or at least 30 microns. In a further embodiment, the first peak maximum may be at least 35 microns. and the second peak maximum is 70 microns or less, or 60 microns or less, or It may be 50 microns or less, or 40 microns or less, or 35 microns or less.

[0043] In yet another embodiment, the first peak maximum is in the range of hB The second peak maximum corresponds to hBN particle size in the 35-50 micron range. It is possible to respond.

[0044] In another embodiment, the 80 percent distribution value (D90-D10) of the hBN particle distribution is at least at least 15 microns, or at least 20 microns, or at least 25 microns, or at least 30 microns, or at least 35 microns, or at least 40 microns; Or at least 45 microns, or at least 50 microns. The 80th percentile value (D90-D10) of the hBN particle distribution is 80 microns or less, or 70 microns or less, or 60 microns or less, or 50 microns or less, or 45 microns or less or below, or 40 microns or less.

[0045] In certain embodiments, a majority of the ceramic particles contained within the composite, e.g., at least 90% by volume, or at least 92% by volume, based on the total volume of the composite particles; or At least 94% by volume, or at least 96% by volume, or at least 98% by volume, or At least 99% by volume may be hBN particles. In certain embodiments, the ceramic particles The particles can consist essentially of hBN particles, and by consisting essentially of hBN particles, it is meant that the particles In the specification, this means that the ceramic particles are not hBN particles and have 0.5% or less by volume. do.

[0046] Surprisingly, certain surface-functionalized hBN particles exhibited complex thermal conductivity of at least 10 W / mK. To achieve a thermal conductivity of 40% or less hB based on the total volume of the composite, It was observed that N can be dispersed in organic polymers with a high degree of orientation already at high N concentrations.

[0047] Many different aspects and embodiments are possible. After reading this specification, those skilled in the art will understand that these aspects and embodiments are illustrative and not restrictive. It will be understood that the above is illustrative only and does not limit the scope of the present invention. The implementation may be according to any one or more of the embodiments listed below.

[0048] Embodiment Embodiment 1. An organic polymer and hexagonal boron nitride (hB) distributed throughout the organic polymer. N) ceramic particles, The amount of hBN particles ranges from 20% to 40% by volume based on the total volume of the composite. , the amount of ceramic particles is 50% by volume or less based on the total volume of the composite; A composite article, wherein the composite has an in-plane thermal conductivity of at least 10 W / mK.

[0049] Embodiment 2. The in-plane March-Dauer orientation parameter η of the hBN particles in the composite is small. at least 50%, or at least 51%, or at least 52%, or at least 53% , or at least 54%, or at least 55%, or at least 56%, or at least or at least 57%, or at least 58%, or at least 59%, or at least 60%, or At least 61%, or at least 62%, or at least 63%, or at least 64% %, or at least 65%.

[0050] Embodiment 3. The average length-to-thickness aspect ratio of the hBN particles is at least 5, or less. At least 10, or at least 20, or at least 30, or at least 40, or at least At least 50, or at least 60, or at least 70, or at least 80, or at least At least 90, or at least 100, or at least 110, or at least 120 10. The composite article of any one of the preceding embodiments.

[0051] Embodiment 4. The average aspect ratio of the hBN particles is 200 or less, or 120 or less, or The composite article of any one of the preceding embodiments, wherein the .lambda.

[0052] Embodiment 5. The hBN particles are at least 1 micron, or at least 3 microns, or is at least 5 microns, or at least 10 microns, or at least 15 microns, Or at least 20 microns, or at least 25 microns, or at least 30 microns or any of the preceding embodiments having an average particle size (D50) of at least 35 microns. A composite article according to any one of the preceding items.

[0053] Embodiment 6. The hBN particles are 100 microns or less, or 70 microns or less, or 50 microns or less, or 45 microns or less, or 40 microns or less, or 35 microns or less, Or 30 microns or less, or 25 microns or less, or 20 microns or less, or 10 microns 10. The method of claim 1, wherein the granular material has an average particle size of 100 microns or less, or 5 microns or less. A composite article containing the above.

[0054] Embodiment 7. Any one of the preceding embodiments, wherein the hBN particles have a multimodal distribution. A composite article as described above.

[0055] Embodiment 8. The hBN particles of embodiment 7 include a combination of three different particle size ranges. A composite article as described above.

[0056] Embodiment 9. A first batch of hBN particles having an average particle size of 3 to 7 microns. a second portion of hBN particles having an average particle size of 12 to 20 microns; and a third portion of hBN particles having an average particle size of 25 to 35 microns. and a third portion of hBN particles having an average particle size of microns. A composite item.

[0057] Embodiment 10. The volume ratio of the first portion to the second and third portions is 0.7:1.0 :1.3~1.3:1.0:0.7, or 0.8:1.0:1.2~1.2:1.0:0 0.8, or in the range of 0.9:1.0:1.1 to 1.1:1.0:0.9. A composite article as described above.

[0058] Embodiment 11. The composite has an electrical volume resistivity of at least 1.0E+12, or any of the preceding embodiments, wherein the A composite article according to any one of the preceding items.

[0059] Embodiment 12. The organic polymer of the composite is a thermoplastic polymer or a thermosetting polymer. 10. The composite article of any one of the preceding embodiments, comprising:

[0060] Embodiment 13. The organic polymer is a silicone polymer, an acrylate polymer, Polyurethane, epoxide polymer, polyamide, polyimide, liquid crystal polymer (LCP) , fluoropolymer, polyethylene, polypropylene, polystyrene, polyester, Polycarbonate, Polybutylene terephthalate (PBT), Polyethylene terephthalate (PET), polyamide, liquid crystal polymer (LCP), polyacrylonitrile (PAN), Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Poly Polysulfone, polyethersulfone, polyphenylene oxide (PPO), polyether Imide, thermoplastic elastomer (TPE, olefin or styrene), polyfluoride Polyvinylidene (PVDF), Perfluoroalkoxyalkane (PFA), Fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), or or any combination thereof. Goods.

[0061] Embodiment 14. Any of the preceding embodiments, wherein the organic polymer comprises a silicone polymer. A composite article according to any one of the preceding items.

[0062] Embodiment 15. The method of embodiment 1, wherein the organic polymer consists essentially of a silicone polymer. 6. A composite article as set forth in claim 6.

[0063] Embodiment 16. The silicone polymer has a molecular weight of at least 10,000 g / mol and at least At least 100,000 g / mol, at least 200,000 g / mol, at least 40 0,000 g / mol, or at least 700,000 g / mol. 18. The composite article of any one of embodiments 16 or 17.

[0064] Embodiment 17. The silicone polymer has a molecular weight of 1,000,000 g / mol or less, or 8 00,000 g / mol or less, or 700,000 g / mol or less, or 500,000 g / mol or less, or 300,000 g / mol or less, or 100,000 g / mol or less 19. The composite article of any one of embodiments 16-18, having a molecular weight of:

[0065] Embodiment 18. Any of the preceding embodiments, wherein the complex further comprises a surfactant. A composite article as described in item 1.

[0066] Embodiment 19. The amount of the surfactant is at least 0.1% by weight and not more than 5% by weight. 18. The composite article of embodiment 17.

[0067] Embodiment 20. The composition of any one of embodiments 27 to 28, wherein the surfactant is a polysiloxane. Composite goods.

[0068] Embodiment 21. The amount of hBN particles is 92% by volume based on the total volume of the ceramic particles; or at least 94%, at least 96%, or at least 98% by volume, or at least 99% by volume of the composite article of any one of the preceding embodiments. .

[0069] Embodiment 22. The ceramic particles of the composite essentially consist of hBN particles. 10. The composite article of any one of the embodiments.

[0070] Embodiment 23. The amount of hBN particles is 39% by volume or less based on the total volume of the composite; or 38% by volume or less, or 37% by volume or less, or 36% by volume or less, or 35% by volume or less , The composite article of any one of the preceding embodiments.

[0071] Embodiment 24. The amount of hBN particles is at least 21% by volume based on the total volume of the composite. , or at least 22% by volume, or at least 23% by volume, or at least 24% by volume; or at least 25% by volume, or at least 26% by volume, or at least 27% by volume, or is at least 28% by volume, or at least 29% by volume, or at least 30% by volume, or At least 31% by volume, or at least 32% by volume, or at least 33% by volume, or less 10. The composite article of any one of the preceding embodiments, wherein the porosity is at least 34% by volume.

[0072] Embodiment 25. The thermal conductivity of the composite is at least 10.5 W / mK, or at least 11.0 W / mK, or at least 11.5 W / mK, or at least 12 W / mK, or is at least 12.5 W / mK, or at least 13.0 W / mK, or at least 13 0.5W / mK, or at least 14W / mK, or at least 14.5W / mK, or less At least 15.0 W / mK, or at least 15.5 W / mK, or at least 16 W / mK, or at least 16.5 W / mK, or at least 17.0 W / mK, or less 17.5W / mK, or at least 18W / mK, or at least 18.5W / mK , or at least 19.0 W / mK, or at least 19.5 W / mK, or at least 20 W / mK.

[0073] Embodiment 26. The thermal conductivity of the composite is 40 W / mK or less, or 30 W / mK or less, or 3. The composite article of any one of the preceding embodiments, wherein the thermal conductivity is less than or equal to 20 W / mK.

[0074] Embodiment 27. The method of any preceding embodiment, wherein the surface of the hBN particles is functionalized with an organic compound. 10. A composite article according to any one of the preceding claims.

[0075] Embodiment 28. The organic compound is a polysiloxane, a polysilane, a silane, or any of these. 28. The composite article of embodiment 27 selected from any combination.

[0076] Embodiment 29. The composite of embodiment 28, wherein the organic compound is a polysiloxane. Product.

[0077] Embodiment 30. The organic compound is covalently bonded to the surface of the hBN particles. A composite article according to any one of claims 1 to 29.

[0078] Embodiment 31. The polysiloxane has at least 100 and no more than 100,000 molecules. 27. The composite article of any one of embodiments 25-26, having an amount

[0079] Embodiment 32. The organic compound contains a fluorine-containing compound, an epoxy compound, or an amine. 28. The composite article of embodiment 27.

[0080] Embodiment 33. A method of forming a composite article, comprising: preparing a mixture of ceramic particles and an organic polymer, The amount of hBN particles is in the range of 20 to 40% by volume based on the total weight of the dispersion. The total amount of ceramic particles is 50% by volume or less based on the total volume of the composite. and applying a layer of the mixture to a mold or substrate; performing an alignment procedure of hBN particles; Solidifying and / or curing the organic polymer or organic polymerizable material to form a composite. and The method wherein the in-plane thermal conductivity of the composite is at least 10 W / mK.

[0081] Embodiment 34. The method further comprises surface functionalizing the hBN particles before preparing the mixture. 34. The method of embodiment 33.

[0082] Embodiment 35. Surface functionalization exfoliates hBN particles to form activated hBN particles. and activating the hBN particles and treating the activated hBN particles with an organic compound. 34. The method according to claim 34.

[0083] Embodiment 36. An embodiment in which the activation comprises introducing OH groups onto the outer surface of the hBN particles. 36. The method of claim 35.

[0084] Embodiment 37. The method of embodiment 34 or 35, wherein stripping and activation are performed simultaneously. Law.

[0085] Embodiment 38. Any one of embodiments 34 to 37, wherein the exfoliation comprises ball milling. The method described below.

[0086] Embodiment 39. The organic compound is a polysiloxane or polysilane containing silicon hydride groups. 39. The method of any of embodiments 35 to 38, wherein the compound is a silane compound, a silane compound, or any combination thereof. The method according to any one of the preceding claims.

[0087] Embodiment 40. The treating step comprises chemically reacting the hBN particles with an organic compound. 40. The method of embodiment 39, comprising:

[0088] Embodiment 41. Chemically reacting hBN particles with organic compounds using a boron catalyst. 41. The method of embodiment 40, comprising using

[0089] Embodiment 42. The boron catalyst comprises tri(pentafluorophenyl)borane. 42. The method of claim 41.

[0090] Embodiment 43. The alignment procedure includes applying pressure to the layers of the mixture. 42. The method according to any one of claims 1 to 42.

[0091] Embodiment 44. The pressure affects the in-plane March-Dorus orientation parameter of the cured composite. 44. The method of embodiment 43, wherein the intensity is adjusted to be at least 50%.

[0092] Embodiment 45. The pressure is at least 2 MPa, or at least 100 MPa, or less 45. The method of embodiment 43 or 44, wherein the pressure is at least 500 MPa. [Example]

[0093] The following non-limiting examples illustrate the present invention.

[0094] Example 1 Preparation of activated hBN powder

[0095] Activated hBN (with OH groups on the surface) for use as a starting material for silane functionalization To prepare the hydroxybenzoates containing hBN, different treatments were carried out.

[0096] In all the experiments carried out, the average particle size was 30 microns and the particle size was 8-10 as. hBN particles with a 2000 stoichiometric ratio were used as starting materials before surface functionalization with silanes. In combination with the introduction of OH groups on the outer surface of hBN particles, different types of exfoliation were observed. It was served.

[0097] Stripping and activation with NaOH (sample BN1) A PQ-N4 planetary ball mill (Across International) containing zirconia beads was used. hBN powder was exfoliated using a zirconia beads exfoliation method. The ratio was approximately 50:1. For milling, 200 g of hBN powder was added to 500 mL of 2 M Mix with NaOH and mill at 200 rpm for 12 hours. Then reduce the mill speed to 400 rpm. The temperature was increased to 100°C and the mixture was milled for 12 or 24 hours. After milling, the zirconia beads were removed and the mixture was milled for 12 or 24 hours. The BN platelets were rinsed with dilute HCl solution and washed with water by vacuum filtration until a neutral pH was obtained. The final powder was dried in a vacuum oven at 50-60°C.

[0098] Peeling in a neutral solvent (sample BN2) The same procedure as above was used to prepare sample BN1, except that neutral water (deionized water) was used. The same experiment was performed.

[0099] Sonication and polydopamine (PDA) treatment (sample BN3) 200 g of hBN powder and 300 mL of isopropyl alcohol (IPA) were added to Fla. Mix together in a ckTek Speedmixer and then sonicate for 30 minutes to exfoliate. I left.

[0100] To introduce hydroxyl groups onto the surface of the hBN particles, the exfoliated hBN was further treated with P It was subjected to DA functionalization.

[0101] PDA functionalization was performed by dissolving 20 g of exfoliated hBN in 8 g of dopamine hydrochloride and 300 mL of Tris Immerse in a solution of buffer solution (10 mM, pH 8.5) and 100 mL of ethanol solution. The mixture was stirred for 12 hours at room temperature in the dark. The pellet was separated by centrifugation at 4000 rpm for 15 minutes and diluted with deionized water and ethanol. The mixture was washed with water and dried at 60°C for 12 hours.

[0102] O2 plasma activation (sample BN4) The plasma treatment of hBN powder was performed using a Pic The oxygen plasma treatment was carried out using an o-SR-PCCE-C low-pressure plasma reactor. It is known that hydroxyl groups can be grafted onto the surface of hBN plates.

[0103] Plasma treatment was performed using a batch size of 15 g of hBN in a 50% O2 / 50% air mixture. The plasma was conducted at 0.3 mbar pressure and 100 W power for 12 minutes. A combination of O2 and air was chosen to introduce water vapor for xyl formation.

[0104] Glycidyl methacrylate plasma polymerization (sample BN5) Glycidyl methacrylate (GMA) is a polymer that is deposited by plasma-enhanced chemical vapor deposition (PECVD). It is an epoxy functional monomer that can be polymerized by applying a power of 40 W or more. This promotes the opening of the epoxide ring and the generation of a hydroxyl group.

[0105] Plasma activation of hBN powder was performed using air gas at 100 W power and 0.3 mbar. The reaction was carried out at a pressure of 1000 kJ for 5 minutes.

[0106] Example 2 Functionalization of activated hBN particles via the Piers-Rubinsztajn reaction Activated hBN Powder Samples of Example 1 (BN1, BN2, BN3, BN4, and BN5) by silanization via the Piers-Rubinsztajn reaction according to the following procedure: 50 g of activated hBN powder was placed in a 5000K flask equipped with a reflux condenser under a N2 atmosphere. Disperse the solution in 300 mL of anhydrous toluene in a 0 mL round-bottom flask, to which 1 mL of toluene 30 mg of the catalyst tris(pentafluorophenyl)borane-B(C6F5)3- was stirred in Furthermore, the flask was used to promote the reaction at the interface of the glass beads and prevent them from forming during peeling. To break the formed hBN stacks, glass beads (number 40, diameter 6 mm) were used. After adding the catalyst, 4.0 mL of silicon hydride (DMS-H 11) was slowly added to the reaction mixture, followed by stirring at a temperature of 60° C. for 12 hours.

[0107] The reaction mixture was then filtered and the siliconized hBN particles were washed with toluene and IPA. to remove the ungrafted silicone.

[0108] As evidence that silicone chains were grafted onto the hBN particles, DRIFT IR Measurements were performed using a siliconized BN1 powder sample. IR spectrum (Figure 3, Spectrum 3) is the Si-CH3 and Si-O- expected from the grafting reaction. The characteristic peaks of Si are clearly visible, confirming the success of grafting. In comparison, IR spectra 1 and 2 shown in Figure 3 are from hBN particles before functionalization. (1) before functionalization and (2) before functionalization and after stripping and activation. .

[0109] Overview of the different types of hBN powders used in the experiments to form hBN-silicone composites. The main points are shown in Table 1.

[0110] Preparation of hBN-silicone composites After siliconization of the activated hBN powder sample, a method for dispersing the hBN particles was used. Composites were prepared using silicone polymer as the matrix.

[0111] The following procedure was performed: A 34% by volume sample of hBN particles was placed on a silicone rubber (AB sp Specialty Andigum H110-0) and crosslinker 2,4-dichlorobenzo By mixing with methyl peroxide (50% in polydimethylsiloxane; Gelest) The weight percent ratio of crosslinker to silicone was about 1-1.5. The formulation contains 2% by weight of Siltech silicone surfactant and 3% by weight of Evonik V The dispersion was mixed in a Brabender mixture at room temperature for approximately 40 minutes. I went for a while.

[0112] From the prepared hBN dispersion, a layer of the dispersion mixture was poured onto a metal plate, and the temperature was adjusted to 34-46 MP. A composite was fabricated by pressing it to a predetermined thickness by applying a pressure of a for 20 minutes. Specifically, a 60,000 lb. load was placed between two 12" x 12" metal plates. The sheet was pressed under a weight. The mixture is pressed between two metal plates containing the rubber to create a desired thickness. After cold pressing, the pressed material (sheet) was cured in an oven at 120°C for 4 minutes. Ta.

[0113] Table 2 provides an overview of the samples prepared, including the type of hBN activation and the complexes formed. The measured thermal conductivity of the coalescence is shown. [Table 1]

[0114] The data summarized in Table 2 show that hBN powder is ball-milled in the presence of NaOH solution. When activated via exfoliation, we show that a surprising increase in thermal conductivity can be achieved. This appears to be the best activation for efficient siliconization, and furthermore, the silicone polymer The polymer has a strong effect on the formation of hBN-containing composites, and the resulting composites have high thermal conductivity. has a rate.

[0115] In sample E1, the amount of hBN was only about 34% by volume based on the total volume of the composite, and the Materials with high thermal conductivity in W / mK were obtained.

[0116] Example 3 Example 2 for Sample E1, except using a different volumetric amount of hBN The composites were formed in the same manner as above. The volume ratios were 25%, 30%, and 38%. The thermal conductivity is measured and the March-Doras orientation parameter is measured.

[0117] Example 4 The same as sample E1 in Example 2 except that low polyethylene was used as the organic polymer. The thermal conductivity and March-Doras orientation parameter are measured. .

[0118] Example 5 For sample E1, a plurality of composite sheets obtained in Example 2 were stacked in layers before curing. The laminate is compressed by applying pressure, after which the silicone A heat treatment is performed to effect curing of the polymer.

[0119] From the pressed and cured multilayer laminate, a 0.5 mm thick composite slice was cut using a diamond. The composite slices are analyzed for thermal conductivity through their thickness (z). The thermal conductivity across the thickness (z-direction, also called the through-plane direction) of the composite slice The conductivity has been measured and is at least 90% of the in-plane thermal conductivity of the multilayer composite of sample E1. Schematic of a composite slice with hBN particles (14) oriented in the through-plane direction. is shown in Figure 1C.

[0120] Thermal conductivity measurement The thermal conductivity is measured using a transient planar light source device (TPS 2500 S, Hot Disk I The instruments and measurements were performed on two samples of the test material. A temperature sensor is placed between the test specimen and the surface of the test specimen, and a heat pulse is introduced to measure the temperature change. The temperature sensor is designed by calculating the thermal conductivity based on the Insulated Hot Disk® Sensor Model 5501 (6.4m Radius) The heat pulse was varied in the range of 60 to 150 mW for 3 to 15 seconds, and the conductivity values ​​were The measurements were performed to ensure that the temperature remained constant regardless of the pulse parameters. Hot Disk Thermal Constants from Disk® Analyser Instruction Manual (2015-04-15) The in-plane thermal conductivity was measured using a slab module, and the through-plane thermal conductivity was measured using a slab module. The anisotropic method was applied to the determination.

[0121] Measurement of the March-Dauras orientation parameter η X-ray diffraction analysis was performed to determine the orientation (also referred to herein as alignment) of the hBN particles within the composite. In the case of in-plane oriented hBN platelets, the principal plane of interest is parallel to the surface. First, 2D XRD spectra were taken at 10° Focused Cu Kα radiation (λ = 1.5418) in step scan mode with angular positions ranging from ~80° Å) were obtained after spot diffraction of the sample on a Bruker D8 diffractometer. (1D) XRD spectra were obtained using the built-in functions of Bruker's EVA software. The results were obtained by integrating the 2D spectrum using Rietveld peak fitting. Using the lattice method, the (002) peak intensity of the oriented hBN pattern was compared with the non-oriented hBN data. Compared to the base pattern, a quantifiable measure of orientation was obtained. The XRD spectrum is shown in Figure 2A. The more (002) hBN planes are aligned parallel to the surface, the As the temperature rises, the relative intensity of the (002) experimental peak increases compared to the database peak. do.

[0122] Peaks in the XRD patterns were analyzed using Bruker's Topas quantitative software. The fitting was performed using the Topas software, which calculates the March-Dorus function W(α) as It has a built-in refinement function for determining March-Dorus parameters using: Please refer to equation (1) below.

number

[0123] The preferred orientation η(r) as a function of the March-Dorus parameter r is given by the following equation (2 ) can be calculated according to

number

[0124] The graph shown in Figure 2B shows the relationship between the March-Dorus parameter r and the The graph shows the relationship between the preferred orientation η(r), also called the "Dorus orientation parameter η". The solid line in the figure shows the actual measured curve, and the dashed line shows the curve as a simplified linear trend line. It is a converted one.

[0125] Electrical volume resistivity measurement The electrical resistivity of the samples was measured according to ASTM D257.

[0126] Measurement of hBN particle size distribution The particle size distribution of hBN particles was measured using a Horiba Laser Scattering P article Size Distribution Analyzer LA-95 The median size (D50) and average size were measured by laser scattering using a 0.0 meter. The expression "is used in accordance with the HORIBA manual definition."

[0127] In the foregoing specification, concepts have been described with reference to specific embodiments. Those skilled in the art will appreciate that various modifications may be made without departing from the scope of the invention as set forth in the following claims. It is understood that various modifications and variations may be made to the present invention. All such modifications shall be considered in an illustrative, not a categorical, sense. are intended to be included within the scope of the present invention.

Claims

1. an organic polymer and hexagonal boron nitride (hBN) particles distributed throughout the organic polymer; and ceramic particles comprising: The amount of the hBN particles is in the range of 20% to 40% by volume based on the total volume of the composite. It is an enclosure, the amount of the ceramic particles is 50 volume % or less based on the total volume of the composite; The composite article, wherein the composite has an in-plane thermal conductivity of at least 10 W / mK.

2. The in-plane March-Dollase orientation of the hBN particles in the composite 10. The composite article of claim 1, wherein the meter η is at least 50.

3. The hBN particles have an average aspect ratio of length (L) to thickness (T) of at least 5.

2. The composite article of claim 1 .

4. The hBN particles have an average particle size (D50) of at least 1 micron and no greater than 70 microns.

10. The composite article of claim 1, comprising:

5. 10. The composite of claim 1, wherein the composite has an electrical volume resistivity of at least 1.0E+12. A composite item.

6. the organic polymer of the composite comprises a thermoplastic polymer or a thermosetting polymer; The composite article of claim 1 .

7. The organic polymer is a silicone polymer, an acrylate polymer, a polyurethane, Epoxide polymers, polyamides, polyimides, liquid crystal polymers (LCPs), fluoropolymers mer, polyethylene, polypropylene, polystyrene, polyester, polycarbonate , polybutylene terephthalate (PBT), polyethylene terephthalate (PET), amide, liquid crystal polymer (LCP), polyacrylonitrile (PAN), polyether ether Polyetherketone (PEEK), polyetherketoneketone (PEKK), polysulfone, Polyethersulfone, polyphenylene oxide (PPO), polyetherimide, thermoplastic Resistant elastomer (TPE, olefin or styrene), polyvinylidene fluoride (PV DF), perfluoroalkoxyalkane (PFA), fluorinated ethylene propylene (F ethylene tetrafluoroethylene (EP), ethylene tetrafluoroethylene (ETFE), or any copolymer thereof 8. The composite article of claim 7, comprising: a polymer; ...

8. The composite article of claim 8 , wherein the organic polymer comprises a silicone polymer.

9. The amount of the hBN particles is at least 92% by volume based on the total volume of the ceramic particles. The composite article according to any one of claims 1 to 8.

10. 10. The composite article of any one of claims 1 to 9, wherein the surface of the hBN particles is functionalized with an organic compound.

11. The organic compound may be polysiloxane, polysilane, silane, or any combination thereof.

12. The composite article of claim 11, wherein the composite article is selected from a laminate.

12. 1. A method of forming a composite article, comprising: preparing a mixture of ceramic particles and an organic polymer, The particles include hBN particles, and the amount of the hBN particles is 20 to 40% based on the total weight of the dispersion. 0% by volume, and the total amount of ceramic particles is in the range of 50% by volume based on the total volume of the composite. % or less; applying a layer of said mixture to a mold or substrate; performing an alignment procedure for hBN particles; solidifying and / or curing the organic polymer or organic polymerizable material to form a composite. and causing The method of claim 1, wherein the composite has an in-plane thermal conductivity of at least 10 W / mK.

13. and further comprising surface functionalizing the hBN particles prior to preparing the mixture. Item 17. The method according to item 16.

14. Surface functionalization exfoliates and activates the hBN particles to form activated hBN particles. and treating the activated hBN particles with an organic compound, The product is a polysiloxane, polysilane, or silane compound containing silicon hydride groups, or The method of claim 17, including any combination thereof.

15. The exfoliation step includes ball milling, and the activation step includes ball milling the hBN particles.

20. The method of claim 18, comprising introducing OH groups onto the surface of the molecule.

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