JP6195108B2 - Modified boron nitride, its production method and composition - Google Patents

Description

  The present invention relates to a modified boron nitride having thermal conductivity and a method for producing the same.

Plastic materials are widely used as materials for electrical and electronic equipment and automobiles as a substitute for metal materials due to the widespread use of engineering plastics with high heat resistance, as well as productivity and freedom of shape. .
On the other hand, in recent years, there has been a further demand for higher performance, smaller size, and lighter weight of the equipment, and the heat generation has increased due to higher integration and larger capacity of semiconductor devices. It is a difficult issue. In addition, there is a strong demand for improving the thermal conductivity of insulating members used in lithium-ion batteries, motors, and inverters as an improvement in the power consumption of electric vehicles.

As a method for maintaining the insulation of the plastic material and imparting thermal conductivity, a technique of adding an inorganic filler is known, and for example, boron nitride, aluminum nitride, alumina, magnesium oxide and the like are used. Among them, boron nitride has high thermal conductivity. However, since it has a hexagonal crystal structure for flakes, there is a problem that the filler is oriented and anisotropy occurs in thermal conductivity. In addition, since boron nitride has a relatively large oil absorption amount, if a large amount of boron nitride is added to the resin, there is a problem that the fluidity is remarkably lowered because the resin is adsorbed, so that the moldability of the resin is maintained. Needed to reduce the amount of boron nitride.

  In order to solve such a problem of boron nitride, for example, a method of activating boron nitride by chemical bonding to the surface of boron nitride (Patent Document 3), a surface treatment method of boron nitride using supercritical carbon dioxide ( Patent document 4) etc. are disclosed. However, even by these methods, the effect of improving the moldability of the resin is insufficient, and the cost is very high, so that it has been difficult to widely use in industry.

JP 2000-233907 A JP 2009-221039 A JP 2010-529938 A JP 2012-529938 A

  The subject of this invention is providing the modified | denatured boron nitride excellent in the filling rate and processability to resin, maintaining its heat conductivity, and its manufacturing method.

  As a result of intensive studies, the present inventors have found that modified boron nitride capable of solving the above problems can be produced by mechanochemical treatment of boron nitride.

That is, the present invention provides a method for producing modified boron nitride, which comprises a step of mechanochemically treating boron nitride, and a modified boron nitride produced thereby.

The present invention also provides a method for producing modified boron nitride that is mechanochemically treated in the presence of water or an organic solvent, and a modified boron nitride produced thereby.

Moreover, the modified boron nitride composition containing the modified boron nitride obtained by the said manufacturing method and a metal coupling agent is provided.

The present invention also provides a surface-treated modified boron nitride obtained by reacting a modified boron nitride obtained by the above production method with a metal coupling agent.

The present invention also provides a resin composition containing the modified boron nitride or the surface-treated modified boron nitride and a resin, and a molded body formed by molding the resin composition.

  The modified boron nitride obtained by the production method of the present invention is excellent as a heat conductive filler for a molding resin because it is excellent in filling rate and processability to the resin while maintaining thermal conductivity. In addition, the surface-treated boron nitride obtained by treating the modified boron nitride with a metal coupling agent is more excellent in thermal conductivity, and thus is suitable as a thermally conductive filler for molding resin. Moreover, the resin composition containing the modified boron nitride and the surface-treated modified boron nitride of the present invention is suitable as a heat conductive material, and the resulting molded article has good heat conductivity.

[Boron nitride]
In the present invention, modified boron nitride can be obtained by modifying boron nitride by mechanochemical treatment. Boron nitride (BN) is known to have various crystal structures such as hexagonal BN and cubic BN, and any of them can be used in the present invention. Among these BN, hexagonal BN is preferable because it is easily available on an industrial scale and is inexpensive. This hexagonal boron nitride can be obtained by heating boron at a high temperature in a nitrogen stream, heating ammonia and boron oxide, or heating ammonium chloride and borax. The boron nitride thus obtained is generally in the form of a scaly or polygonal plate, and particles having a large crystal size are advantageous for use in a heat conductive material. The average particle size of boron nitride is preferably 10 μm or more. More preferably, it is 15-60 micrometers.

[Mechanochemical treatment]
The mechanochemical treatment of the present invention refers to a treatment in which a compressive force and a shear force are simultaneously applied to boron nitride. The mechanochemical treatment is not particularly limited as long as it is an apparatus capable of simultaneously applying a compressive force and a shearing force to an object to be processed. Examples of such apparatuses include a medium agitation mill such as a bead mill, a disperser such as a paint conditioner, a planetary ball mill (manufactured by Fritsch), a vibration mill, a pressure kneader, a kneader such as a two-roll mill, a rotating ball mill, a high A hybridization system (manufactured by Nara Machinery Co., Ltd.), mechanomicros (manufactured by Nara Machinery Co., Ltd.), mechanofusion system (manufactured by Hosokawa Micron Corporation), and the like can be used.

The mechanochemical treatment conditions as described above vary depending on the apparatus to be used and cannot be said unconditionally, but are preferably set so as not to destroy the modified boron nitride particles produced by the treatment. If the load energy is too strong, particle breakage progresses, and particle size reduction and filler decomposition occur partially. Therefore, it is important to appropriately control the processing conditions. For example, when using a paint conditioner, the processing time is 20 to 60 minutes using light beads such as glass beads. When using a planetary ball mill, the rotation speed of the pedestal is 200 to 600 rpm and the processing time is 5 It can be done in ~ 20 minutes.

By the mechanochemical treatment, the surface of boron nitride is activated to become modified boron nitride. The details of how it is modified are unknown, but it is believed that the surface atoms / number of molecules increases in the process of pulverizing boron nitride, and is activated by the disorder of their bonding state. .

  As the mechanochemical treatment, either a wet method using water or an organic solvent or a dry method not using it can be used, but a mechanochemical treatment using a wet method using water or an organic solvent is preferable. This is because the modification of boron nitride is promoted by the mechanochemical treatment in the wet method.

[Metal coupling agent]
Since the surface of the modified boron nitride of the present invention is modified, the surface material tends to adhere firmly when surface treatment is performed with a metal coupling agent. Therefore, effects of surface treatment with a metal coupling agent such as fluidity are more easily obtained.

  Examples of the metal coupling agent used in the present invention include various coupling agents such as a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, and a tin coupling agent. It is a coupling agent.

  Examples of the silane coupling agent include vinyl silanes such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane; γ-methacryloxypropyltrimethoxysilane; β- (3,4 -Epoxycyclohexyl) Epoxy silane such as ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane; N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane Aminosilanes such as N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane; and other silane coupling agents , Γ-mercaptopropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, and the like.

  Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite) Titanate, tetra (2,2-diallyloxymethyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl Titanate, isopropyl isostearoyl diacryl titanate, isop Pirutori (dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri (N- aminoethyl-aminoethyl) titanate, dicumyl phenyloxy acetate titanate, diisostearoyl ethylene titanate.

  Examples of the zirconium coupling agent include tetra-n-propoxyzirconium, tetra-butoxyzirconium, zirconium tetraacetylacetonate, zirconium dibutoxybis (acetylacetonate), zirconium tributoxyethyl acetoacetate, zirconium butoxyacetylacetonate bis. (Ethyl acetoacetate) and the like.

  Examples of the aluminum coupling agent include aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butyrate, aluminum ethylate, ethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), Alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetoacetate) and the like can be mentioned.

  As a method of reacting the metal coupling agent with the modified boron nitride, a known and commonly used method may be used. For example, the metal coupling agent and the modified boron nitride may be mixed and heated. When the metal coupling agent is bonded to the surface of the modified boron nitride, the surface-modified modified boron nitride is obtained.

(Resin composition)
The resin composition of the present invention contains a resin and the modified boron nitride or the surface-modified modified boron nitride.
As the resin, a thermosetting resin or a thermoplastic resin can be used.

  The thermosetting resin is a resin having characteristics that can be substantially insoluble and infusible when cured by heating or means such as radiation or a catalyst. Specific examples include phenol resin, urea resin, melamine resin, benzoguanamine resin, alkyd resin, unsaturated polyester resin, vinyl ester resin, diallyl terephthalate resin, epoxy resin, silicone resin, urethane resin, furan resin, ketone resin, xylene. Examples thereof include resins and thermosetting polyimide resins. These thermosetting resins can be used alone or in combination of two or more.

  The thermoplastic resin refers to a resin that can be melt-molded by heating. Specific examples thereof include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, Polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile resin, polyamide resin, polyacetal resin, polybutylene terephthalate resin, polylactic acid resin, polyphenylene ether resin, modified polyphenylene ether resin, polycarbonate Resin, polysulfone resin, polyphenylene sulfide resin, polyetherimide resin, polyethersulfone Fat, polyarylate resins, thermoplastic polyimide resins, polyamideimide resins, polyether ether ketone resin, polyketone resin, liquid crystal polyester resins, fluorine resins, syndiotactic polystyrene resin, cyclic polyolefin resin. These thermoplastic resins can be used alone or in combination of two or more.

[Heat conduction material]
The resin composition of the present invention can be suitably used as a heat conductive material.
Moreover, since the cured | curing material obtained is excellent also in heat conductivity, it is favorable as a heat conductive member.

  Hereinafter, the present invention will be described with examples, but the present invention is of course not limited thereto.

<Example 1>
A mixture of 40 parts of boron nitride (DENKABORON NITRIDE SGP manufactured by Denki Kagaku Kogyo) and 100 parts of toluene was dispersed with a paint conditioner for 1 hour using glass beads having a diameter of 0.5 mm. The solvent was filtered off from the obtained dispersion, and the filter cake was blown and dried to obtain modified boron nitride (D-1).

(Resin composition)
Diglycidyl ether of bisphenol A (manufactured by DIC Corporation: trade name EPICLON 850-S, epoxy equivalent 188 g / eq.) 45.5 g, polytetramethylene glycol diglycidyl ether 30 (Sakamoto Pharmaceutical Co., Ltd., epoxy equivalent 412 g) / Eq.) 50 g and dicyandiamide Amicure AH-154 (Ajinomoto Fine Techno Co., Ltd.) 4.5 g were mixed to prepare a resin mixed solution (E).
With respect to the obtained resin liquid mixture (E), the said modified boron nitride (D-1) was mix | blended according to the compounding table | surface of following Table 1, knead | mixed with three rolls, and the resin composition was obtained by defoaming.

〔Evaluation method〕
The following evaluations were performed and the results are shown in Table 1.
○ Fluidity of the resin composition When the viscosity of the resin composition is measured at 25 ° C and a shear rate of 1.0 (1 / s) using RHEOSTRES RS150 (manufactured by HAAKE), the viscosity is 600 Pa · s or less. ◎, a case where the viscosity is 600 to 1000 Pa · s is made ◯, and a case where the viscosity exceeds 1000 Pa · s is made X.

○ Resin molded body evaluation (thickness direction)
Using the resin composition, it was cured by hot press molding to prepare a resin molded article test piece A (60 × 110 × 0.8 mm) (temporary curing conditions 170 ° C. × 20 minutes, main curing conditions 170 ° C. × 2 hours). ). About the test piece cut out to 10x10 mm from the obtained molded object, the heat conductivity was measured using the heat conductivity measuring apparatus (LFA447 nanoflash, the product made from NETZSCH).

○ Thermal conductivity of molded body (in-plane direction)
Using the resin composition, a resin molded body test piece B (110 mm × 70 mm × 1 mm) is prepared by hot press molding, and heat conductivity is measured using a hot wire type thermal conductivity measuring device (QTM-500 manufactured by Kyoto Electronics Industry). Was measured.

<Example 2>
The same operation as in Example 1 was performed except that 40 parts of methanol was used instead of 40 parts of toluene blended in Example 1, to obtain a modified boron nitride (D-2), a resin composition, and a resin molded body, and evaluation was performed. went. -

<Example 3>
The same operation as in Example 1 was performed except that 40 parts of water was used instead of 40 parts of toluene blended in Example 1, to obtain a modified boron nitride (D-3), a resin composition, and a resin molded body, and evaluation was performed. went.

<Example 4>
A mixture of 40 parts boron nitride (SGP) and 100 parts water was dispersed with a paint conditioner for 1 hour using glass beads with a diameter of 0.5 mm. The filter cake obtained by filtering the solvent from the obtained dispersion was put into a flask, 50 parts of isopropanol and 0.8 part of 3- (N-phenyl) aminopropyltrimethoxysilane were added, and the mixture was reacted at 75 ° C. for 3 hours. The reaction product was filtered and dried to obtain a coupling agent-treated modified boron nitride (D-4). For the obtained D-4, a resin composition was prepared according to the composition shown in Table 1, a resin molded product was obtained in the same manner as in Example 1, and the thermal conductivity in the thickness direction was measured.

<Example 5>
For D-4, a resin composition was prepared according to the composition of Table 1, a resin molded body was obtained in the same manner as in Example 1, a resin molded body was obtained in the same manner as in Example 1, and heat conduction in the thickness direction The rate was measured.

<Example 6>
Coupling was carried out in the same manner as in Example 4 except that 0.8 part of isopropyltriisostearoyl titanate was used instead of 0.8 part of 3- (N-phenyl) aminopropyltrimethoxysilane compounded in Example 4. Agent-treated modified boron nitride (D-5) was obtained. For the obtained D-5, a resin composition was prepared according to the composition shown in Table 1, a resin molded product was obtained in the same manner as in Example 1, and the thermal conductivity in the thickness direction was measured.

<Comparative Example 1>
Commercially available boron nitride (DENKABORON NITRIDE SGP manufactured by Denki Kagaku Kogyo Co., Ltd.) was used as it was, and a resin composition was prepared according to the composition shown in Table 1. A resin molded product was obtained and evaluated in the same manner as in Example 1.

<Comparative example 2>
Resin compositions were prepared according to the compositions in Table 1, resin molded bodies were obtained and evaluated in the same manner as in Example 1.

<Comparative Example 3>
Boron nitride (DENKABORON NITRIDE SGP manufactured by Denki Kagaku Kogyo) is put in a flask, 50 parts of isopropanol and 0.8 part of 3- (N-phenyl) aminopropyltrimethoxysilane are added and reacted at 75 ° C. for 3 hours. The product was filtered and dried to obtain a coupling agent-treated boron nitride (H-1). A resin composition was prepared for the obtained H-1 according to the composition shown in Table 1, a resin molded product was obtained in the same manner as in Example 1, and the thermal conductivity in the thickness direction was measured.

The modified boron nitride of the present invention is excellent as a heat conductive material, and the resin composition containing the modified boron nitride can be suitably used as a heat conductive material.
Moreover, since the cured | curing material obtained is excellent also in heat conductivity, it is favorable as a heat conductive member.

Claims (4)

Production of modified boron nitride for heat conductive material having an average particle size of 15 to 60 μm, comprising a step of mechanochemical treatment of boron nitride in the presence of water or an organic solvent so as not to destroy the particles Method. The manufacturing method according to claim 1, wherein the modified surface of boron nitride by mechanochemical treatment is further reacted with a metal coupling agent .   The production method according to claim 2, wherein the metal coupling agent is at least one selected from a silane coupling agent, a titanate coupling agent, a zirconate coupling agent, a zirconium aluminate coupling agent, and an aluminate coupling agent. The manufacturing method of the resin composition for heat conductive materials which mixes the modified | denatured boron nitride obtained with the manufacturing method as described in any one of Claims 1-3, and resin .