Modified boron nitride as well as preparation method and application thereof

Abstract

The invention relates to modified boron nitride as well as a preparation method and application thereof, the interlayer spacing of the modified boron nitride is greater than or equal to 1.2 nm, and the modified boron nitride in unit molar weight contains 0.5-1.0 mol of hydrogen bonds. When the modified boron nitride is used for preparing the adhesive film, not only is the heat-conducting property improved, but also the elongation at break and the peel strength can be improved, so that the adhesive film can meet the requirements of industrial application when being used for a printed circuit board.

Description

Technical Field

[0001] The present invention relates to the technical field of the electronics industry, and particularly to a modified boron nitride, a preparation method thereof, and an application thereof. Background Art

[0002] Adding high-thermal-conductivity fillers is a reliable method to improve the thermal conductivity of the adhesive film. Among them, boron nitride (BN) low-dimensional materials are widely used due to their excellent insulation and thermal conductivity. However, in the actual use process, boron nitride has poor dispersibility, resulting in poor elongation at break of the adhesive film prepared therefrom and unable to meet the use requirements. At the same time, due to its layered structure, it is easy to slip and peel off, resulting in low peel strength of the adhesive film prepared therefrom and unable to meet the use requirements. Summary of the Invention

[0003] Based on this, in view of the above problems, it is necessary to provide a modified boron nitride, a preparation method thereof, and an application thereof; using the modified boron nitride to prepare an adhesive film is not only beneficial to improving the thermal conductivity, but also can improve the elongation at break and peel strength, so that the adhesive film can meet the requirements of industrial applications when used in printed circuit boards.

[0004] A modified boron nitride, wherein the interlayer spacing of the modified boron nitride is greater than or equal to 1.2 nm, and 0.5 mol - 1.0 mol of hydrogen bonds are contained in the modified boron nitride per unit molar amount.

[0005] In one embodiment, the density of the modified boron nitride is greater than or equal to 0.50 g / cm 3 .

[0006] In one embodiment, the modified boron nitride includes boron nitride and a polyhydroxy polysaccharide compound disposed in the interlayer voids of the boron nitride, and the polyhydroxy polysaccharide compound is linked to the boron nitride through hydrogen bonds.

[0007] In one embodiment, the polyhydroxy polysaccharide compound satisfies at least one of the following conditions:

[0008] (1) The polyhydroxy polysaccharide compound is in a flake structure or a layered structure;

[0009] (2) The degree of polymerization of the polyhydroxy polysaccharide compound is 5000 - 10000.

[0010] In one embodiment, the polyhydroxy polysaccharide compound includes at least one of cellulose, lignin, and starch.

[0011] A preparation method of a modified boron nitride as described above, comprising the following steps:

[0012] Mix boron nitride, polyhydroxy polysaccharide compounds, ionic liquid and a solvent, and heat and react them under a protective atmosphere to obtain the modified boron nitride.

[0013] In one embodiment, the preparation method further satisfies at least one of the following conditions:

[0014] (1) The mass ratio of the boron nitride to the polyhydroxy polysaccharide compound is 8:7 - 2:1;

[0015] (2) The mass of the ionic liquid is 1% - 5% of the mass of the boron nitride;

[0016] (3) The reaction temperature is 100°C - 150°C;

[0017] (4) The reaction time is 3h - 10h.

[0018] A resin composition includes a first filler, a thermosetting resin and a curing agent, and the first filler is selected from the modified boron nitride as described above.

[0019] In one embodiment, the resin composition further satisfies at least one of the following conditions:

[0020] (1) The mass ratio of the thermosetting resin to the modified boron nitride is 1:2 - 1:2.9;

[0021] (2) The thermosetting resin has a benzene ring structure;

[0022] (3) The curing agent includes at least one of amine-based curing agents, phenol-based curing agents, naphthol-based curing agents, benzoxazine-based curing agents, carbodiimide-based curing agents, cyanate ester-based curing agents, active ester-based curing agents, anhydride-based curing agents;

[0023] (4) The resin composition further includes at least one of a second filler, a curing accelerator, a flame retardant, a leveling agent, a solvent.

[0024] An insulating adhesive film made of the resin composition as described above.

[0025] A circuit board made of the insulating adhesive film as described above.

[0026] A printed circuit board made of the circuit board as described above.

[0027] The modified boron nitride of the present invention not only increases the interlayer spacing to more than 1.2 nm, thereby improving the dispersibility of the modified boron nitride in the epoxy resin system, but also regulates the hydrogen bond content within a specific range, enabling the modified boron nitride to have greater interlayer forces. Thus, when the modified boron nitride is used as a thermal conductive filler to prepare a film, it can significantly improve the elongation at break and peel strength of the obtained film. Furthermore, when the obtained film is used in a printed circuit board, it can meet the requirements of industrial applications. Detailed Embodiments

[0028] To facilitate the understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention. In the present invention, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0030] The present invention provides a modified boron nitride, wherein the interlayer spacing of the modified boron nitride is greater than or equal to 1.2 nm, and 0.5 mol - 1.0 mol of hydrogen bonds are contained in the modified boron nitride per unit molar amount.

[0031] The modified boron nitride of the present invention not only increases the interlayer spacing of the modified boron nitride to more than 1.2 nm, thereby improving the dispersibility of the modified boron nitride in the epoxy resin system, but also regulates the hydrogen bond content within a specific range, enabling the modified boron nitride to have greater interlayer forces. Thus, when the modified boron nitride is used as a thermal conductive filler to prepare a film, it can significantly improve the elongation at break and peel strength of the obtained film. Furthermore, when the obtained film is used in a printed circuit board, it can meet the requirements of industrial applications.

[0032] It is understandable that the interlayer spacing of the modified boron nitride includes, but is not limited to, any point value among 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 1.9 nm, 2.0 nm or the range value between any two of them; the number of hydrogen bonds contained in the modified boron nitride per unit mole includes, but is not limited to, any point value among 0.5 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1.0 mol or the range value between any two of them.

[0033] In an embodiment of the present invention, the density of the modified boron nitride is greater than or equal to 0.50 g / cm 3 , including but not limited to 0.50 g / cm 3 , 0.52 g / cm 3 , 0.55 g / cm 3 , 0.58 g / cm 3 , 0.60 g / cm 3 , 0.65 g / cm 3 Among any point value or the range value between any two of them, through the filling effect of the polyhydroxy polysaccharide compound on the interlayer voids of boron nitride, the modified boron nitride has a more compact structure, so that when the modified boron nitride is added to the epoxy resin system, it is beneficial to improve the structural stability of the epoxy resin system. Furthermore, when used to prepare the adhesive film, the elongation at break of the adhesive film can be appropriately increased.

[0034] In an embodiment of the present invention, the modified boron nitride includes boron nitride and a polyhydroxy polysaccharide compound disposed in the interlayer voids of the boron nitride. The polyhydroxy polysaccharide compound is linked to the boron nitride by hydrogen bonds. By setting the polyhydroxy polysaccharide compound in the interlayer voids of boron nitride, while maintaining the excellent thermal conductivity without destroying the layered structure of boron nitride, the interlayer spacing of boron nitride can be effectively increased, and the polyhydroxy polysaccharide compound and boron nitride are linked by hydrogen bonds, which can improve the interlayer force of the modified boron nitride, thereby further increasing the elongation at break and peel strength of the adhesive film prepared from the modified boron nitride.

[0035] In an embodiment of the present invention, the polyhydroxy polysaccharide compound is in a flake structure or a layered structure, which is more conducive to the polyhydroxy polysaccharide compound to fully fill the interlayer voids of boron nitride, thereby further improving the dispersibility of the modified boron nitride in the epoxy resin system and being beneficial to increasing the elongation at break of the adhesive film.

[0036] In an embodiment of the present invention, the degree of polymerization of the polyhydroxyl polysaccharide compound is 5000 - 10000, including but not limited to any point value among 5000, 6000, 7000, 8000, 9000, 10000 or the range value between any two of them. By regulating the degree of polymerization of the polyhydroxyl polysaccharide compound within a certain range, it is not only beneficial to ensure that the modified boron nitride has abundant hydrogen bonds and reduce the slip between the boron nitride layer structures, but also can make the prepared adhesive film have a certain fluidity, thereby further improving the peel strength of the adhesive film.

[0037] It should be noted that in the polyhydroxyl polysaccharide compound, polyhydroxyl means that the number of hydroxyl groups contained in each repeating unit structure is greater than or equal to 2. By forming hydrogen bonds through the reaction of hydroxyl groups with boron nitride, it is beneficial to reduce the slip between the boron nitride layer structures, thereby improving the peel strength of the adhesive film.

[0038] In an embodiment of the present invention, the polyhydroxyl polysaccharide compound includes at least one of cellulose, lignin, and starch. Among them, cellulose is preferably nanocrystalline cellulose. The polyhydroxyl polysaccharide compound has good compatibility with epoxy resin and has an effect similar to that of a reinforcing material, which is beneficial to further improving the elongation at break of the adhesive film.

[0039] The present invention provides a method for preparing the modified boron nitride as described above, including the following steps:

[0040] Mix boron nitride, polyhydroxyl polysaccharide compound, ionic liquid, and solvent, and heat and react under a protective atmosphere to obtain the modified boron nitride.

[0041] For the preparation method provided by the present invention, on the one hand, the ionic liquid is used to fully dissolve the polyhydroxyl polysaccharide compound, enabling the polyhydroxyl polysaccharide compound to overcome the interlayer force and effectively insert into the interlayer voids of boron nitride, thereby increasing the layer spacing without destroying the layered structure of boron nitride; on the other hand, the ionic structure of the ionic liquid can also effectively increase the layer spacing of boron nitride, which is beneficial to improving the effect of intercalation modification.

[0042] In an embodiment of the present invention, the mass ratio of boron nitride to the polyhydroxyl polysaccharide compound is 8:7 - 2:1, including but not limited to any point value among 8:7, 4:3, 5:2, 5:3, 2:1 or the range value between any two of them, preferably 5:3 - 2:1, to improve the dispersion of boron nitride, thereby improving the elongation at break of the adhesive film.

[0043] In an embodiment of the present invention, the mass of the ionic liquid is 1% - 5% of the mass of the boron nitride, preferably 2.0% - 2.5%, including but not limited to any point value among 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% or the range value between any two of them, and more preferably 2.1% - 2.3%, which is beneficial to improving the peel strength of the adhesive film.

[0044] It can be understood that the ionic liquid is composed of an organic cation and an inorganic (or organic anion). Among them, the cation includes at least one of quaternary ammonium salt ions, quaternary phosphonium salt ions, imidazole salt ions, and pyrrole salt ions, and the anion includes at least one of halogen ions, tetrafluoroborate ions, and hexafluorophosphate ions.

[0045] In an embodiment of the present invention, the reaction temperature is 100°C - 150°C, preferably 110°C - 120°C; the reaction time is 3h - 10h, preferably 4h - 5h; the protective gas for forming the protective atmosphere includes but is not limited to nitrogen; the heating reaction method includes but is not limited to oil bath heating; the solvent is preferably an organic solvent, and the organic solvent includes but is not limited to methyl ethyl ketone; before the heating reaction, it is preferred to ultrasonically disperse the mixture first; after the heating reaction, it is preferred to wash and dry with the same solvent.

[0046] The present invention provides a resin composition, which includes a first filler, a thermosetting resin, and a curing agent, and the first filler is selected from the modified boron nitride as described above.

[0047] In an embodiment of the present invention, the mass ratio of the thermosetting resin to the modified boron nitride is 1:2 - 1:2.9, preferably 1:2.3 - 1:2.5.

[0048] In an embodiment of the present invention, the thermosetting resin has a benzene ring structure and is similar to the structure of polyhydroxy polysaccharide compounds, which is beneficial to improving compatibility and thus improving the elongation at break of the adhesive film prepared from the resin composition.

[0049] In an embodiment of the present invention, the thermosetting resin includes but is not limited to at least one of epoxy resin, hydrocarbon resin, thermosetting polyphenylene ether resin, and cyanate ester resin.

[0050] Among them, the epoxy resin preferably includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, triphenol type epoxy resin, naphthol novolac epoxy resin, and phenol novolac epoxy resin.

[0051] In an embodiment of the present invention, the curing agent includes at least one of amine-based curing agents, phenol-based curing agents, naphthol-based curing agents, benzoxazine-based curing agents, carbodiimide-based curing agents, cyanate ester-based curing agents, active ester-based curing agents, and anhydride-based curing agents.

[0052] In order to further improve processability and preparation efficiency, the resin composition also includes a curing accelerator. Specifically, the curing accelerator includes but is not limited to at least one of a phosphorus curing accelerator, an amine curing accelerator, an imidazole curing accelerator, a guanidine curing accelerator, and a metal curing accelerator, and preferably includes at least one of a phosphorus curing accelerator, an amine curing accelerator, and an imidazole curing accelerator.

[0053] In one embodiment of the present invention, the resin composition further comprises other thermally conductive fillers as second fillers. Preferably, the second filler comprises aluminum nitride, silicon dioxide, or silicon nitride.

[0054] It is understandable that the resin composition further includes a solvent; according to the performance requirements of different film products, the resin composition may also include other additives such as a flame retardant and a leveling agent, which is not limited in the present invention.

[0055] The present invention also provides an insulating adhesive film made of the resin composition as described above, wherein the insulating adhesive film has excellent thermal conductivity and elongation at break.

[0056] It should be noted that the insulating adhesive film in the present invention can be prepared by an existing method, and the present invention does not limit this. Preferably, after the above-mentioned resin composition is mixed evenly, it is coated on the surface of the support film, and after being dried in an oven, an insulating film is formed, and a protective film is laminated on the surface of the insulating film. The insulating adhesive film includes a support film, an insulating film and a protective film stacked in sequence, and the support film is preferably at least one of a polyethylene terephthalate (PET) film, a polyimide (PI) film and a polypropylene (BOPP) film, and the protective film is selected from a polypropylene (BOPP) film.

[0057] The present invention also provides a circuit substrate made of the insulating adhesive film as described above. The circuit substrate is not prone to delamination, board bursting and other undesirable phenomena, has a long service life, can meet higher processing requirements, and has broad application prospects.

[0058] In one embodiment of the present invention, the circuit substrate includes an insulating layer and a conductive layer arranged on at least one surface of the insulating layer, wherein the insulating layer is pressed from one or more laminated insulating films as described above, and the insulating film is obtained by peeling off the reinforcing film and the protective film from the insulating adhesive film, and the conductive layer is selected from conductive materials such as copper foil and aluminum foil, and the present invention is not limited to this.

[0059] In another embodiment of the present invention, the circuit board includes an insulating layer, a metal plate disposed on one surface of the insulating layer, and a conductive layer disposed on the other surface of the insulating layer. Among them, the insulating layer is formed by pressing one or two or more laminated insulating films as described above. The insulating film is obtained by peeling the insulating adhesive film from the reinforcing film and the protective film. The metal plate is selected from metal plates such as copper plates, aluminum plates, and copper-aluminum alloy plates, and the conductive layer is selected from conductive materials such as copper foils and aluminum foils. The present invention does not limit this.

[0060] The present invention also provides a printed circuit board made of the circuit board as described above. The printed circuit board has a relatively high service life, can meet diversified application scenarios, and has relatively high market application potential.

[0061] Specifically, the printed circuit board is made from the circuit board through processes such as drilling board, hole finishing, micro-etching, pre-impregnation, activation, acceleration, electroless copper, and copper thickening. The present invention does not limit this.

[0062] Hereinafter, the modified boron nitride and its preparation method and application will be further described through the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0063] Example 1

[0064] 300 g of boron nitride, 150 g of nanocrystalline cellulose (layered structure, degree of polymerization of 8000), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and then the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0065] Example 2

[0066] 300 g of boron nitride, 150 g of lignin (layered structure, degree of polymerization of 7000), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and then the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0067] Example 3

[0068] 300 g of boron nitride, 150 g of starch (layered structure, degree of polymerization of 7,500), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0069] Example 4

[0070] 300 g of boron nitride, 150 g of nanocrystalline cellulose (rod-like structure, degree of polymerization of 8,000), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0071] Example 5

[0072] 300 g of boron nitride, 150 g of nanocrystalline cellulose (layered structure, degree of polymerization of 4,000), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0073] Example 6

[0074] 300 g of boron nitride, 150 g of nanocrystalline cellulose (layered structure, degree of polymerization of 12,000), 6.9 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of butanone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C and the reaction time was 5 h. The reaction product was washed with butanone and dried to obtain modified boron nitride.

[0075] Example 7

[0076] 240 g of boron nitride, 150 g of nanocrystalline cellulose (lamellar structure, degree of polymerization of 8000), 5.52 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of methyl ethyl ketone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C, the reaction time was 5 h, and the reaction product was washed with methyl ethyl ketone and dried to obtain modified boron nitride.

[0077] Example 8

[0078] 240 g of boron nitride, 210 g of nanocrystalline cellulose (lamellar structure, degree of polymerization of 9000), 5.52 g of ionic liquid (1-vinyl-3-butylimidazolium tetrafluoroborate), and 500 mL of methyl ethyl ketone were added to a beaker, ultrasonically dispersed for 1 h, then added to a three-necked flask, and the three-necked flask was placed in an oil bath. Under a nitrogen atmosphere, the reaction temperature was 110 °C, the reaction time was 5 h, and the reaction product was washed with methyl ethyl ketone and dried to obtain modified boron nitride.

[0079] Comparative Example 1

[0080] The difference between Comparative Example 1 and Example 1 was that 150 g of polyethylene glycol (non-lamellar structure, degree of polymerization of 10000) was used instead of 150 g of nanocrystalline cellulose.

[0081] Comparative Example 2

[0082] The difference between Comparative Example 2 and Example 1 was that 150 g of polyvinylpyrrolidone (non-lamellar structure, degree of polymerization of 8000) was used instead of 150 g of nanocrystalline cellulose.

[0083] Comparative Example 3

[0084] The difference between Comparative Example 3 and Example 1 was that 150 g of polylactic acid (non-lamellar structure, degree of polymerization of 12000) was used instead of 150 g of nanocrystalline cellulose.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 was that 150 g of polyacrylic acid (non-lamellar structure, degree of polymerization of 7000) was used instead of 150 g of nanocrystalline cellulose.

[0087] The products prepared in the above examples and comparative examples were tested, and the results are shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] Application Example

[0092] Take 272 parts by weight of the products obtained from the above examples and comparative examples respectively, mix them with 100 parts by weight of 3,3’,5,5’-tetraalkyl-4,4’-biphenyldiglycidyl ether (epoxy group equivalent: 180 g / eq, number average molecular weight: 950 g / mol), 1 part by weight of dimethylimidazole curing accelerator and 25 parts by weight of 4-aminophenyl sulfone curing agent, and uniformly disperse them to obtain a resin composition.

[0093] Uniformly coat the resin composition on a PET film (RZ 0.1 μm, thickness 35 μm), dry it at 100 °C for 5 min, and then laminate an OPP film on the surface to obtain an adhesive film. Use an oven to cure the adhesive film at 180 °C for 90 min to cure the resin composition layer. After peeling the cured resin composition layer from the PET film and the OPP film, an insulating film is obtained.

[0094] Perform performance tests on the insulating films obtained from the above examples and comparative examples. The test indexes and methods are as follows:

[0095] (1) Elongation at break: According to GB / T 1040.3, use a universal testing machine to conduct a tensile test on the insulating film, and measure its elongation at break at 23 °C;

[0096] (2) Peel strength: Test according to the test standard of GB / T 4722-2017;

[0097] (3) Thermal conductivity: Test according to the test standard of ASTM D5470.

[0098] The test results are shown in Table 2.

[0099] Table 2

[0100]

[0101]

[0102] According to the test results in Table 1 and Table 2, it can be seen that the modified boron nitride provided by the present invention can not only improve the thermal conductivity of the adhesive film when used in the epoxy resin system, but also enhance the peel strength and elongation at break of the adhesive film, and can meet the requirements of industrial applications when used in printed circuit boards.

[0103] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0104] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A modified boron nitride, characterized in that: The interlayer spacing of the modified boron nitride is greater than or equal to 1.2 nm, and a unit mole of the modified boron nitride contains 0.5 mol to 1.0 mol of hydrogen bonds.

2. The modified boron nitride according to claim 1, characterized in that The density of the modified boron nitride is greater than or equal to 0.50 g / cm 3 .

3. The modified boron nitride according to claim 1, characterized in that: The modified boron nitride comprises boron nitride and a polyhydroxy polysaccharide compound disposed in the interlayer gaps of the boron nitride, and the polyhydroxy polysaccharide compound is linked to the boron nitride through hydrogen bonds.

4. The modified boron nitride according to claim 3, characterized in that: The polyhydroxy polysaccharide compound satisfies at least one of the following conditions: (1) The polyhydroxy polysaccharide compound has a sheet-like structure or a layered structure; (2) The degree of polymerization of the polyhydroxy polysaccharide compound is 5000-10000.

5. The modified boron nitride according to claim 3 or 4, characterized in that: The polyhydroxy polysaccharide compound includes at least one of cellulose, lignin and starch.

6. A method for preparing modified boron nitride according to any one of claims 1 to 5, characterized in that: The steps include: Boron nitride, polyhydroxy polysaccharide compounds, ionic liquid and solvent are mixed, and heated to react under a protective atmosphere to obtain the modified boron nitride.

7. The method for preparing modified boron nitride according to claim 6, characterized in that: The preparation method also satisfies at least one of the following conditions: (1) The mass ratio of the boron nitride to the polyhydroxy polysaccharide compound is 8:7-2:1; (2) The mass of the ionic liquid is 1%-5% of the mass of the boron nitride; (3) The reaction temperature is 100°C-150°C; (4) The reaction time is 3h-10h.

8. A resin composition, characterized in that It comprises a first filler, a thermosetting resin and a curing agent, wherein the first filler is selected from the modified boron nitride according to any one of claims 1 to 5.

9. The resin composition according to claim 8, characterized in that The resin composition further satisfies at least one of the following conditions: (1) The mass ratio of the thermosetting resin to the modified boron nitride is 1:2-1:2.9; (2) The thermosetting resin has a benzene ring structure; (3) the curing agent includes at least one of an amine curing agent, a phenol curing agent, a naphthol curing agent, a benzoxazine curing agent, a carbodiimide curing agent, a cyanate curing agent, an active ester curing agent, and an acid anhydride curing agent; (4) The resin composition further comprises at least one of a second filler, a curing accelerator, a flame retardant, a leveling agent, and a solvent.

10. An insulating adhesive film made from the resin composition according to claim 8 or 9.

11. A circuit substrate made of the insulating adhesive film according to claim 10.

12. A printed circuit board made using the circuit substrate as claimed in claim 11.

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