JP2019019212A - Surface modified inorganic powder - Google Patents

Abstract

To realize a high function in a composite material containing a high polymer material and an inorganic material, by improving compatibility of the inorganic material and the high polymer material on which a surface modification treatment is conducted.SOLUTION: There is provided a surface modified inorganic powder which is a reaction product between an inorganic material and a surface modifier, in which the surface modifier has a surface modification part Q and a reaction part with the inorganic material R, the surface modified inorganic powder contains the inorganic material and the surface modification part Q covering a surface of the inorganic material. The surface modification part has a property of compatibility to the high polymer material which is an object for compatibility. Each differences between contributions of the surface modification part, δd, δp, δhon Hansen solubility parameters δd, δp, and δhof the surface modifier, and Hansen solubility parameters of the high polymer material δd, δpand δh; δd-δd, δp-δp, and δh-δhis in a range of ±3(J/cm)respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface-modified inorganic powder used in a composite material in which an inorganic material and a polymer material are combined.

  A composite material containing an inorganic material and a polymer material can be made by changing the type of the inorganic material and the polymer material, so that the conductive material, EMC (electromagnetic compatibility) material, recording material, magnetic material, slidable material, sealing Since it can be used as a wide variety of functional materials such as damping materials, vibration damping materials, dental materials, heat insulating materials, heat conductive materials, buoyancy materials, etc., it is applied in various fields.

  For example, the conductive material is carbon black, metal powder, etc., the magnetic material is ferrite powder, the Nd—Fe—B magnetic powder, etc., the thermally conductive material is alumina, and the slidable material is graphite. Molybdenum sulfide is used as an inorganic material.

  As the polymer material, in consideration of thermal characteristics, mechanical characteristics, shape, construction method, etc., thermoplastic resins such as polybutylene terephthalate (PBT), polyamide (PA), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), etc., or A thermosetting epoxy resin, a phenol resin, or the like is appropriately selected.

  In these composite materials, in order to enhance the functionality, the inorganic material is highly filled, highly dispersed, or highly fluidized. For example, in the case of a conductive material, the conductivity can be improved by highly filling carbon black having conductivity. In addition, for example, a surface modifier or the like can be added to the inorganic material powder, so that the inorganic material powder in the composite material can be highly filled, highly dispersed, or highly fluidized.

  Therefore, selecting an effective surface modifier is an important point for enhancing the functionality of the composite material.

  The numerical values of the solubility of each material that can be used to select surface modifiers in composite materials are the Kauri-butanol number, the Solubility Grade developed by the National Gallery of Art Research Project. , Wax number, Hildebrand solubility parameter, Hansen solubility parameter, etc. expressed as the amount of solvent that can be added to the benzene / beeswax solution while maintaining solubility. Among them, the most widely applied are the Hildebrand solubility parameter and the Hansen solubility parameter.

  The Hildebrand solubility parameter only considers van der Waals forces and is only applicable to nonpolar molecules. On the other hand, the Hansen solubility parameter is applicable to polar molecules because it considers hydrogen bonding force and polar force in addition to van der Waals force, and has a wide range of applications. The Hansen solubility parameter is mainly applied to the determination of the compatibility between two different substances such as solvents, solvent and resin, and resin and resin.

  For example, in Patent Document 1, when separating a flame retardant from a thermoplastic resin composition containing a flame retardant, the resin composition is brought into contact with a solvent having a hydrogen bond term δH of a Hansen solubility parameter of 6.0 or more. . Thereby, the flame retardant is actively dissolved in the solvent.

In Patent Document 2, a water-soluble ethylenically unsaturated monomer containing an acidic group and at least partially neutralized is a di (meth) acrylate of a polyol having 2 to 20 carbon atoms, and 2 to 20 carbon atoms. A highly water-absorbent resin is formed using a base resin in the form of a powder polymerized with one or more internal cross-linking agents selected from the group consisting of poly (meth) acrylates of polyols. Further, the base resin is a substance in which δ _p defined by the Hansen solubility parameter satisfies δ _p <12 (J / cm ³ ) ^1/2 , and δ _H is 4 <δ _H <6 (J / cm ³ ) ¹ It is shown that surface crosslinking is performed with at least one selected from the group consisting of a material satisfying ^{/ 2} and a material satisfying δ _tot δ _tot > 31 (J / cm ³ ) ^1/2 .

JP 2002-37914 A JP-T-2006-516877

  As described above, in order to increase the functionality of a composite material including an inorganic material and a polymer material, when the inorganic material powder is highly filled, highly dispersed, or highly fluidized, the phase between the inorganic material and the polymer material It is necessary to increase solubility.

  In order to increase the compatibility between inorganic materials and polymer materials, it is necessary to select a surface modifier so that the compatibility between the surface-modified inorganic material and the polymer material is excellent. There is. However, no guidance has been found to date to predict and evaluate the solubility of surface modified inorganic materials. For this reason, in selecting the optimum surface modifier, it is necessary to repeat experiments and evaluate a large number of prototypes, and only to find one suitable surface modifier. , With significant development time and industrial costs.

  In Patent Document 2, the Hansen solubility parameter is used for evaluating the compatibility between the water-absorbing polymer and the surface cross-linking agent. However, in this method, it is difficult to evaluate the compatibility between the surface-modified inorganic powder and the polymer material.

  As described above, there is no guideline for improving the functionality of composite materials including inorganic materials and polymer materials, and secondary materials such as surface modifiers, and a new technical idea is desired. It was.

In view of the above, one aspect of the present invention is a surface-modified inorganic powder that is a reaction product of an inorganic material and a surface modifier,
The surface modifying agent has a surface modifying portion Q and a reaction portion R with the inorganic material, and the surface modified inorganic powder is a surface that covers the surface of the inorganic material and the inorganic material. A reforming section Q,
The surface modification portion Q has a property of being compatible with a polymer material to be compatible with,
Contributions by the surface modification part Q in the Hansen solubility parameters δd _S , δp _S , δh _S of the surface modifier δd _SQ , δp _SQ , δh _SQ, and Hansen solubility parameters δd _A , δp _A , each difference δd _SQ -δd _a and _{δh a, δp SQ -δp a,} δh SQ -δh a are both within the scope of ^{± 3 [(J / cm 3} ) 1/2], surface modification Relates to a fine inorganic powder.

  According to the present disclosure, it is possible to increase the functionality of a composite material including a polymer material and an inorganic material.

It is a schematic diagram which shows the structure of the compound for bonded magnets using the surface modification inorganic powder which concerns on one Embodiment of this invention. 5 is a graph showing the relationship between the HSP distance Ra of the surface modified portion relative to the polyamide resin and the viscosity of the compound in a bonded magnet compound using a polyamide resin as a polymer material. It is a graph which shows the relationship between the HSP distance Ra of the surface modification part with respect to LCP resin, and the viscosity of a compound in the compound for bonded magnets which used LCP resin for the polymeric material.

  In the following, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  The surface-modified inorganic powder according to the embodiment of the present invention is a surface-modified inorganic powder that is a reaction product of an inorganic material and a surface modifier, and the surface modifier includes the surface-modified portion Q, The surface-modified inorganic powder includes the inorganic material and a surface-modified portion Q that covers the surface of the inorganic material. In other words, the surface modifying portion Q is supported on the inorganic material so as to cover the surface of the inorganic material by the reaction of the surface modifying agent with the inorganic material. The surface modification portion Q has a property of being compatible with a polymer material to be compatible.

At this time, the contribution δd _SQ , δp _SQ , δh _SQ by the surface modification part Q in the Hansen solubility parameters δd _S , δp _S , δh _S of the surface modifier and the Hansen solubility parameters δd _A , δp _A , each difference δd _SQ -δd _a and δh _a, δp _SQ -δp _a, the .delta.h _SQ - [Delta] H _a, both, within a range of ^{± 3 (J / cm 3)} 1/2. That is,
| Δd _SQ −δd _A | ≦ 3 (J / cm ³ ) ^1/2 ,
| Δp _SQ −δp _A | ≦ 3 (J / cm ³ ) ^1/2 , and
| Δh _SQ −δh _A | ≦ 3 (J / cm ³ ) ^1/2 ,
The surface of the inorganic material is modified using a surface modifying agent that satisfies the requirements to obtain a surface modified inorganic powder.

  The Hansen Solubility Parameter (hereinafter referred to as “HSP parameter” as appropriate) is an index that represents the solubility between materials (swelling property), and the solubility is represented by the London dispersion force term (δd), the dipole. This is represented by a three-dimensional vector of an interatomic force term (δp) and a hydrogen bond force term (δh). For each material, when the solubility is represented by the position coordinates (δd, δp, δh) in the three-dimensional space, the closer the distance between the materials (HSP distance) in the three-dimensional space, the higher the compatibility. To do.

  Here, the London dispersive force is an attractive force generated by a bias of charge in a molecule in a minute time, and is equal to a van der Waals force in a nonpolar molecule. The solubility due to London dispersion is δd. The force between dipoles is an attractive force acting between dipoles of a molecule having a dipole moment (polar molecule), and the solubility due to the force between dipoles is δp. Hydrogen bonding force is a strong intermolecular force generated by a positively bonded hydrogen atom covalently bonded to an atom having a large electronegativity and attracting another negative atom to an equilibrium distance close to the radius of the anion. . The solubility resulting from the hydrogen bonding force is δh.

When the HSP parameter of the material i is (δd _i , δp _i , δh _i ) and the HSP parameter of the material j is (δd _j , δp _j , δh _j ), the HSP distance Ra between the material i and the material j is The compatibility of the material i and the material j becomes higher as Ra is smaller.
[Formula 1]
Ra = {4 (δd _i −δd _j ) ² + (δp _i −δp _j ) ² + (δh _i −δh _j ) ² } ^1/2

  Therefore, the HSP parameter of the polymer material used together with the inorganic material is measured, and the surface modifier having the surface modifying portion at a position where the HSP parameter is close to the parameter is reacted with the inorganic material. Thus, the surface of the inorganic material can be modified to obtain a surface-modified inorganic powder. The surface-modified inorganic powder thus obtained has improved compatibility with the polymer material, and it is possible to increase the functionality of the composite material such as high packing, high dispersion, or high fluidity. Become.

  In addition, as a method for measuring the HSP parameter of the target polymer material, for example, an HSPiP program (Hansen Solubility Parameters in Practice) using the Hansen sphere method, [May 10, 2017 Search], Internet <URL: http://www.hansen-solubility.com/HSPiP/> is known. In this method, the solubility of the target material is confirmed by a dissolution experiment in a plurality of solvents with known Hansen solubility parameters. Thereafter, the Hansen solubility parameter of the solvent used in the dissolution experiment is plotted in a three-dimensional space of (δd, δp, δh). Next, the minimum sphere surrounding the group of Hansen solubility parameters of the solvent in which the material dissolves is obtained without including the Hansen solubility parameter of the solvent in which the material does not dissolve. The center coordinate of the minimum sphere is set as the Hansen solubility parameter of the target material.

  Other experimental methods for obtaining the HSP parameter include a method of measuring the particle diameter when the target material powder is dispersed in a solvent, and calculating the HSP parameter from the difference of the particle diameter for each solvent, and the solvent There is a method of measuring a contact angle when the liquid is dropped on a target material and calculating an HSP parameter from a difference of the contact angle for each solvent.

It should be noted that in evaluating the compatibility between the surface-modified inorganic powder and the polymer material, the HSP parameters (δd _S , δp _S , δh _S ) of the surface modifier are not used as they are, but the surface modification is performed. Of the HSP parameters of the agent, the contribution (δd _SQ , δp _SQ , δh _SQ ) by the surface modification part Q is derived, and the compatibility with the polymer material is evaluated. The contribution of the HSP parameters due to the part that reacts with and binds to the inorganic material of the surface modifier need not be considered. Moreover, it is not necessary to consider also about the HSP parameter of an inorganic material.

  In this way, by evaluating the compatibility of the polymer material using only the HSP parameters of the surface modification part Q that actually interacts with the polymer material, the inorganic material and the polymer material after the surface modification It is possible to improve the compatibility. As a result, in addition to the inorganic material and the polymer material, a composite material containing a secondary material such as a surface modifier can be highly filled, highly dispersed, or highly fluidized.

As a method for obtaining the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameter by the surface modification unit, a method of calculating the Hansen solubility parameter of the surface modifier using a molecular group contribution method can be mentioned. In the molecular group contribution method, the chemical structure of the target material is divided into molecular groups such as —CH ₃ , —CH ₂ —, —COOH, —OH, etc., and the London dispersion force, dipole force, and This is a method of calculating the Hansen solubility parameter of the entire chemical structure by calculating and summing the energy and force of the hydrogen bonding force. By this method, among the HSP parameters (δd _S , δp _S , δh _S ) of the surface modifier, contributions by molecular groups constituting the surface modification portion Q excluding the reaction portion R with the inorganic material (δd _SQ , δp _SQ , δh _SQ ) can be derived. (Δd _SQ , δp _SQ , δh _SQ ) is obtained as an HSP parameter of the molecular structure when a molecular structure consisting only of the molecular group constituting the surface modification portion Q is assumed. For example, for the dispersion term, the HSP parameter δd _{S of the} entire surface modifier is an average weighted with a weight proportional to the molecular weight of the contribution δd _SR by the reaction portion R and the contribution δd _SQ by the surface modification portion Q.

By using molecular group contribution _{method, (δd SQ, δp SQ,} δh SQ) is a molecule groups constituting the surface modification portion Q and k, the molecular weight of the surface modification portion Q and _{V Q, Fd} k, Fp _k and Eh _k can be derived from the following Equation 2 as a molar attractive constant due to the dispersion force term due to the molecular group k, a molar attractive constant due to the force between the dipoles, and hydrogen bond energy, respectively.
[Formula 2]
δd _SQ = Σ _k Fd _k / V _Q
δp _SQ = {Σ _k (Fp _k ) ² } ^1/2 / V _Q
δh _SQ = (Σ _k Eh _k / V _Q ) ^1/2

When designing a composite material in which a polymer material and an inorganic material are combined based on the present invention, first, the inorganic material and the polymer material used in the composite material are naturally determined from the specifications of the desired composite material. . In view of this, a surface modifier for inorganic material suitable for making the inorganic material and polymer material compatible is specified. The surface modifier has a reaction portion R that binds to the inorganic material and a surface modification portion Q that is compatible with the polymer material. _A surface modifier having a position where the HSP parameters (δd _SQ , δp _SQ , δh _SQ ) of the surface modifier Q are close to the values of the HSP parameters (δd _A , δp _A , δd _A ) of the polymer material. By using it, the compatibility between the surface-modified inorganic powder and the polymer material is increased, and the composite material can be highly filled, highly dispersed, highly fluidized, and the like.

Specifically, | δd _SQ −δd _A | ≦ 3 (J / cm ³ ) ^1/2 , | δp _SQ −δp _A | ≦ 3 (J / cm ³ ) ^1/2 , and | δh _SQ −δh. By using a surface modifier that satisfies all the conditions of _A | ≦ 3 (J / cm ³ ) ^1/2 , the compatibility of the surface-modified inorganic powder and the polymer material is increased, and the composite material is highly filled. High dispersion, high fluidization and the like are possible, and high performance of the composite material is achieved.

Conventionally, when evaluating the compatibility between the surface-modified inorganic powder and the polymer material, the HSP parameters (δd _M , δp _M , δh _M ) of the inorganic material before the surface modification are used as the HSP parameters of the polymer material. (Δd _A , δp _A , δh _A ) or the HSP parameters (δd _S , δp _S , δh _S ) of the entire surface modifier including the reactive portion R with the inorganic material Comparison was made with HSP parameters (δd _A , δp _A , δh _A ). However, even if the HSP parameters of the inorganic material and the polymer material are compared, it is difficult to evaluate the compatibility between the surface-modified inorganic powder and the polymer material. In addition, the HSP parameters (δd _S , δp _S , δh _S ) of the entire surface modifier include a contribution from the reactive portion R that does not interact with the polymer material. For this reason, considering the HSP parameters of the entire surface modifier, even if a surface modifier with a small HSP distance Ra from the polymer material is selected, only the surface modifier Q excluding the reactive portion R is considered. The HSP parameters (δd _SQ , δp _SQ , δh _SQ ) are far from the HSP parameters of the polymer material. As a result, at least one of | δd _SQ −δd _A |, | δp _SQ −δp _A | and | δh _SQ −δh _A | exceeds 3 (J / cm ³ ) ^1/2 , and the above condition is satisfied. It was difficult to realize a surface modifier satisfying all of the above.

For example, when the polymer material has an amide bond, δd _SQ is in the range of 14 ≦ δd _SQ ≦ 20, δp _SQ is in the range of 6.5 ≦ δp _SQ ≦ 12.5, and δh _SQ is 9 A surface modifier in the range of 0.1 ≦ δh _SQ ≦ 15.1 may be used. As a result, the compatibility between the inorganic material and the polymer material having an amide bond is improved, and the composite material can be highly filled, highly dispersed, or fluidized, and the high performance of the composite material is achieved. The More preferably, in addition to the above conditions, by using a surface modifier having an Ra of 3.7 or less represented by Formula 1, a composite material having a remarkably low viscosity and excellent fluidity is realized. it can.

  The specific chemical structure of the surface modifier that satisfies the above conditions and includes the surface modifying portion Q suitable for the polymer material having an amide bond is represented by, for example, the following chemical formulas (1) to (11). Structure. However, in chemical formula (1)-(11), R points out the reaction part couple | bonded with an inorganic material. The portion excluding R corresponds to the surface modification portion Q. The specific structure of the R portion will be described later.

For example, as an example of using a monocyclic aromatic compound having a reactive portion R and having a phenolic hydroxyl group in the surface modifying portion Q, surface modifying agents represented by the following chemical formulas (1) to (3) are given. It is done.

Examples of the surface modifier having an ethylene group (—CH ₂ CH ₂ —) in the surface modifier Q include surface modifiers represented by the following chemical formulas (4) to (8).

As an example, the surface modifier represented by the following chemical formula (4) further has a carboxyl group (—COOH) in the surface modifier Q.

As an example, each of the surface modifiers represented by the following chemical formulas (5) and (6) further has an amino group (—NH ₂ ) in the surface modifier Q.

As an example, each of the surface modifiers represented by the following chemical formulas (7) and (8) further has a thiol group (—SH) in the surface modifier Q.

  Examples of the surface modifier having a vinylene group (—CH═CH—) in the surface modifier Q include surface modifiers represented by the following chemical formulas (9) to (11).

As an example, the surface modifier represented by the following chemical formula (9) further has a carboxyl group (—COOH) in the surface modifier Q.

As an example, the surface modifying agent represented by the following chemical formula (10) further has a thiol group (—SH) in the surface modifying portion Q.

As an example, the surface modifying agent represented by the following chemical formula (11) further has an amino group (—NH ₂ ) in the surface modifying portion Q.

  In addition, as an example of a specific chemical structure of a surface modifier including a surface modifying portion that is particularly suitable for a polymer material that exhibits liquid crystallinity in a molten state, the following chemical formulas (12) to (15) ). In chemical formulas (12) to (15), R represents a reactive moiety that binds to the inorganic material. The portion excluding R corresponds to the surface modification portion Q. The specific structure of the R portion will be described later.

The chemical formulas (1) to (15) are examples, and the structure of the surface modification portion Q may be any of an aromatic compound, an aliphatic compound, and an alicyclic compound. Examples of the functional group possessed by the surface modification portion Q include phenolic or alcoholic hydroxyl groups, carboxyl groups, amino groups, thiol groups, halogen groups, and nitrile groups, but are not limited thereto. Moreover, these functional groups cannot be introduced only into the specific compounds exemplified in chemical formulas (1) to (15). Any chemical structure can be adopted as long as δd _SQ , δp _SQ , and δh _SQ satisfy the above conditions and can be stably synthesized.

  Examples of the surface modifier include a silane coupling agent, a titanate coupling agent, or phosphonic acid.

  When a silane coupling agent is used as the surface modifier, examples of the specific chemical structure of the surface modifier including the reaction portion (R portion) with the inorganic material include the following chemical formulas (16) to (25). ). The structure represented by the chemical formula In the chemical formulas (16) to (25), Q is a surface modification portion, and corresponds to a portion excluding the R portion in the chemical formulas (1) to (15). As the structure of Q, the structures shown in the above chemical formulas (1) to (15) can be suitably used.

  When a titanate coupling agent is used as the surface modifier, examples of the specific chemical structure of the surface modifier including the reaction portion (R portion) with the inorganic material include the following chemical formulas (26) to (28). ). In chemical formulas (26) to (28), Q is a surface modification portion, and corresponds to a portion excluding the R portion in chemical formulas (1) to (15).

In the chemical formulas (26) to (28), Ti is tetravalent, and in the chemical formula (26), the surface modification portion Q has three functional groups (Q ₁ , Q ₂ , Q ₃ and each bonded to Ti. ). In this _case, Q 1, _{Q 2,} and considering all the contributions of the Hansen solubility parameters by _{Q 3,} Q 1, _{Q 2,} and the contribution by the entire surface modification portion Q comprising _{Q 3 (δd SQ, δp SQ} , Δh _SQ ), δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A are set to satisfy the above conditions. In formula (27) and (28), the surface modification portion Q is comprised of two functional groups which each is bound to Ti _(Q 1, and _{Q 2),} also in this case, similarly, _{Q 1} and The contribution of the Hansen solubility parameter by the entire surface modification part Q including Q ₂ is (δd _SQ , δp _SQ , δh _SQ ), and δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A are the above conditions To satisfy.

  Preferably, the reaction portion R of the surface modifier has an alkoxy group, and the alkoxy group reacts with the inorganic material to form a bonding site between the inorganic material and the surface modified portion.

  For example, when a silane coupling agent having a structure represented by chemical formula (16) is used as the surface modifier, an alkoxy group (methoxy group) present in the reaction portion reacts with an inorganic material, and a silanol group generated by hydrolysis. Reacts with a hydroxyl group present on the surface of the inorganic material M, and the inorganic material and the surface modified portion Q are bonded by the bonding of Si-OM. In the case of the structure of formula (16), three silanol groups can be generated. Of these three silanol groups, all can react with the inorganic material, but one or two silanol groups can dehydrate and condense with the silanol groups of another adjacent surface modifier. Thereby, the coupling | bonding of an inorganic material and the surface modification part Q becomes strong.

  Similarly, for example, when a titanate coupling agent having a structure represented by the chemical formula (26) is used, an alkoxy group (isopropoxy group) present in the reaction portion reacts with the inorganic material M, and Ti—O—M bonds, The inorganic material and the surface modification portion Q are combined.

Moreover, organic phosphonic acid (Q-PO (OH) ₂ ) can also be used as a surface modifier. Q is a surface modification part, and corresponds to a part excluding the R part in chemical formulas (1) to (15). As the structure of Q, the silane coupling agents shown in the chemical formulas (16) to (25) and the titanate coupling agents shown in the chemical formulas (26) to (28) are used. The structure shown in (15) can be suitably used.

  When the above organic phosphonic acid is used as a surface modifier, the phosphonic acid has two hydroxyl groups in the reaction portion R with the inorganic material. In this case, one of the two hydroxyl groups of phosphonic acid reacts with the hydroxyl group of the inorganic material M, and a P—O—M bond is generated by the dehydration reaction, thereby forming a binding site between the inorganic material and the surface modification portion. Is done. Furthermore, the other hydroxyl group of phosphonic acid can supply protons to regenerate the hydroxyl group on the surface of the inorganic material M. The regenerated hydroxyl group can be bonded to the hydroxyl group of another phosphonic acid by a dehydration reaction. In this way, an inorganic material whose surface is modified with high density by a chain reaction is obtained.

  In one embodiment of the present invention, the inorganic material is preferably a magnetic material. More preferably, the magnetic material is at least one selected from the group consisting of Nd—Fe—B based magnetic powder, Sm—Fe—N based magnetic powder, Sm—Co based magnetic powder, and ferrite based magnetic powder. Including. With this configuration, the magnetic powder can be highly filled, highly dispersed, and highly fluidized, a high-magnetism resin magnet can be realized, and the optimum magnetic powder for a bond magnet compound can be provided.

  Hereinafter, the surface-modified inorganic powder according to one embodiment of the present invention will be described taking as an example the case of using it for a compound for a bonded magnet and a bonded magnet. FIG. 1 is a schematic view showing the structure of a compound for a bonded magnet as a composite material composed of a surface-modified inorganic powder and a polymer material according to an embodiment of the present invention.

  As shown in FIG. 1, a bonded magnet compound (composite material) 5 includes a surface-modified inorganic powder 4 and a polymer material (resin) 2. The surface modified inorganic powder 4 includes a rare earth magnetic powder (inorganic material) 1 and a surface modified portion 3. The surface modification portion 3 covering the rare earth magnetic powder 1 is formed as a result of the reaction between the rare earth magnetic powder 1 and the surface modifier.

  The material constituting the rare earth magnetic powder 1 is not particularly limited. For example, Nd—Fe—B magnetic powder, Sm—Co magnetic powder, Sm—Fe—N magnetic powder, or a mixture of these magnetic powders should be adopted. Can do. Among the above magnetic powders, it is more preferable to employ Nd—Fe—B magnetic powder, Sm—Fe—N magnetic powder, and a mixture of these magnetic powders.

  Moreover, the heat resistance of the magnetic powder can be further enhanced by previously coating the rare earth magnetic powder with a heat resistant coating. The heat resistant coating is not particularly limited, but is preferably an inorganic phosphoric acid compound.

It is preferable that the content of the rare earth magnetic powder 1 is adjusted to be in the range of 66 to 83% by volume or in the range of 92 to 98% by mass with respect to the total amount of the rare earth bonded magnet. The rare earth magnetic powder content is preferably adjusted so that the density of the rare earth bonded magnet is in the range of 5.4 Mg / m ^{3 to} 6.5 Mg / m ³ . By setting the content of the rare earth magnetic powder 1 to 66% or more by volume or 92% or more by mass, high magnetic properties can be obtained. In addition, by making the content of rare earth magnetic powder 1 83% or less by volume or 98% or less by mass, it is possible to suppress a decrease in fluidity of the compound for bonded magnets, making it difficult to form into bonded magnets. Can be suppressed.

  In a rare earth bonded magnet or the like, various devices for increasing the content of magnetic powder contained in the bonded magnet are employed in order to improve magnetic characteristics. For example, the content of magnetic powder is increased by mixing magnetic powder having a large average particle diameter and magnetic powder having a small average particle diameter and filling the gap between the magnetic powder having a large average particle diameter with a magnetic powder having a small average particle diameter. Techniques are commonly used. Of course, in the present invention, it is possible to use a mixture of a magnetic powder having a large average particle diameter and a magnetic powder having a small average particle diameter.

  Specific examples of the rare earth magnetic powder 1 include isotropic Nd—Fe—B magnetic powder (trade names: MQP-7-8, MQP-8-5, MQP-10-8.5HD, manufactured by Magnequench) MQP-11-8, MQP-13-9, MQP-14-9, MQP-14-12, MQP-14-13, MQP-15-7, MQP-15-9HD, MQP-16-7, MQP- 16-9HD, MQP-B, MQP-B +, MQP-S-11-9) can be used. The average particle diameter is, for example, 90 μm. These magnetic powders can be used after applying a phosphate coating for preventing oxidation.

  As the polymer material 2, a polyamide-based resin can be suitably used as the polymer material having an amide bond. Specifically, “Unitika nylon 6 grade A1012” manufactured by Unitika Ltd. can be used. The general name of this resin is polyamide 6 resin. In this embodiment, in addition to polyamide 6 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 66 resin, polyamide 610 resin, polyamide 612 resin, polyamide 1010 resin, polyamide 1012 resin, polyamide 6T resin, polyamide 9T Resin, polyamide 10T resin, or a mixture of several of these materials can be used.

  The shape of the polyamide resin is not particularly limited. For example, powder, beads, pellets, or a mixture of these embodiments may be employed.

  Among the polyamide-based resins, it is particularly preferable to use polyamide 6 resin. Polyamide 6 resin has a relatively high fluidity and melting point, and is suitable for applications requiring high heat resistance.

  The molecular weight of the polyamide resin is preferably lower as long as the desired strength is obtained. Moreover, you may employ | adopt what mixed the polyamide resin from which molecular weight differs.

  Alternatively, as the polymer material 2, a polymer material exhibiting liquid crystallinity in a molten state may be used. Specifically, a so-called LCP resin (liquid crystal polymer) can be used. As an example of the LCP resin, Ueno Pharmaceutical Co., Ltd. trade name “UENO LCP A8100” can be mentioned, but is not limited thereto, and if it is a resin having the same characteristics as the above LCP resin (liquid crystal polymer), Is available.

In consideration of the HSP parameter of the polymer material, the surface modifying agent has an HSP parameter of the surface modifying portion 3 of the above relational expression | δd _SQ −δd _A | ≦ 3 (J / cm ³ ) ^1/2 , | δp _A material that satisfies all the conditions of _SQ −δp _A | ≦ 3 (J / cm ³ ) ^1/2 and | δh _SQ −δh _A | ≦ 3 (J / cm ³ ) ^1/2 is selected. When the polymer material 2 is a polyamide resin, for example, a surface modifier having a chemical structure represented by the above chemical formulas (1) to (11) can be suitably used. When the polymer material 2 is an LCP resin, for example, a surface modifier having a chemical structure represented by the chemical formulas (12) to (15) can be suitably used.

  The compound for bonded magnet is intended to eliminate defects in the manufacturing process, etc., and additives such as lubricants, antioxidants, heavy metal deactivators, plasticizers, and modifiers are appropriately surface modified. It can be included separately from the agent. For example, an ethylenediamine-stearic acid-sebacic acid polycondensate can be used as an additive for reducing the viscosity of the compound and increasing fluidity. As a specific example, a trade name “Light Amide WH-215” manufactured by Kyoeisha Chemical Co., Ltd. can be used.

  The manufacturing method of the magnet compound and bond magnet of this embodiment includes the following processes, for example.

(Production of surface-modified rare earth magnetic powder)
First, an organic solvent such as toluene and the rare earth magnetic powder 1 are placed in a beaker or the like and stirred. Further, a solution in which a surface modifier is mixed and dissolved in an organic solvent in advance is added and further stirred. In this way, the surface of the rare earth magnetic powder 1 is reacted with the surface modifier, and the surface of the rare earth magnetic powder 1 is coated with the surface modifying portion 3.

  Thereafter, the coated rare earth magnetic powder is separated from the organic solvent using a centrifuge. The separated rare earth magnetic powder is again washed with an organic solvent and then dried under reduced pressure to obtain the rare earth magnetic powder 1 (surface modified inorganic powder 4) whose surface is coated with the surface modified portion 3.

(Manufacture of compound for bonded magnet)
A kneading extruder or kneader in which a mixture of a rare earth magnetic powder 1 (surface-modified inorganic powder 4), a polymer material (resin) 2, and other additives, the surface of which is coated with a surface modification portion 3, is heated to a high temperature. And knead. The bonded magnet compound 5 is produced by processing the kneaded material with a pelletizer or the like. The shape of the bonded magnet compound 5 is not particularly limited. For example, powder, beads, pellets, or a mixture of these shapes may be employed.

(Manufacture of bonded magnets)
The above-described bonded magnet compound 5 is processed into a predetermined shape using an injection molding machine, a transfer molding machine, or the like, and a bonded magnet is manufactured.

  The bonded magnet compound 5 is heated and pressurized and melted by the injection molding machine. The melt of the bond magnet compound 5 is injected into a molding die placed on an injection molding machine, thereby filling the inside of the die. The bonded magnet compound 5 filled in the molding die is solidified by cooling to complete the bonded magnet. Note that the bonded magnet in this state is not magnetized and is not magnetized. The non-magnetized bonded magnet is magnetized by a magnetizing device as it is or after being incorporated into a mounted product.

  Evaluation of the produced cylindrical bond magnet can evaluate density using the Archimedes method. Moreover, magnetic characteristics can be evaluated using a VSM (Vibrating Sample Magnetometer).

  FT-IR (Fourier Transform Infrared Spectroscopy), FD-MS (Field Desorption Mass Spectroscopy), GPC (Gel Permeation Chromatography), GC-MS (Gas Chromatograph Mass) Analysis), analysis using NMR (Nuclear Magnetic Resonance), etc., the surface modification part (surface modifier) is included in the compound for the bond magnet, and the surface modification part is included in the bond magnet. It can be confirmed that (surface modifier) remains.

  Next, embodiments of the present invention will be further described based on examples.

<< Examples 1 to 11 >>
In accordance with the above-described method for producing rare earth magnetic powder, “MQP-14-12” manufactured by Magnequen Co., Ltd. is treated with a surface modifier as an inorganic material (rare earth magnetic powder), and polyamide 6 resin (Unitika Ltd.) as a polymer material is treated. “Unitika Nylon 6 Grade A1012”) and “Light Amide WH-215” manufactured by Kyoeisha Chemical Co., Ltd. as additives are mixed and kneaded at a predetermined blending ratio, and the kneaded product is processed into pellets with a pelletizer or the like. A compound for a bonded magnet was obtained. The blending ratio of the inorganic material, the polymer material, the additive, and the surface modifier was 94.25: 5: 0.5: 0.25 in terms of mass ratio, respectively. The kneading temperature was 250 ° C.

  As the surface modifier, the structures shown in the above chemical formulas (1) to (11) were synthesized and used as the surface modifiers in Examples 1 to 11, respectively. As the structure of the R portion, a trimethoxysilane group represented by the chemical formula (16), a triethoxysilane group represented by the chemical formula (17), or phosphonic acid was appropriately selected.

  About the produced compound for bonded magnets, the viscosity which is a parameter | index of fluidity | liquidity was measured using the capillary rheometer. The viscosity of the bonded magnet compound at 300 ° C. was measured.

  Moreover, the HSP parameter of the polymer material was measured according to the above-mentioned HSPiP program. Specifically, when a dissolution experiment was performed in a solvent with 33 known HSP parameters, 5 were dissolved at room temperature, and the other 28 were not dissolved. The 33 solvents for which dissolution experiments were performed are shown below, including dissolution / non-dissolution results.

  Dissolved solvent: p-chlorophenol, trifluoroacetic acid, hexafluoroisopropanol, 2,2,2-trifluoroethanol, 2-fluoroethanol

  Solvent not dissolved: acetic acid, acetone, acetonitrile, aniline, benzyl alcohol, bromobenzene, 1-bromonaphthalene, γ-butyrolactone (GBL), 1-chlorobutane, chloroform, p-chlorotoluene, o-dichlorobenzene, dimethyl sulfoxide (DMSO), 1,4-dioxane, ethanol, ethanolamine, fluorobenzene, formamide, methanol, N-methylformamide, 1-methylimidazole, octane, quinoline, 1,1,2,2-tetrabromoethane, tetrahydrofuran ( THF), toluene, 1,1,2-trichloroethane, 4- (trifluoromethyl) acetophenone

From this result, the HSP parameter of the polymer material (polyamide 6) is obtained by obtaining a Hansen sphere that contains the solvent to be dissolved inside the sphere, the solvent that does not dissolve is outside the sphere, and has the smallest radius. (Δd _A , δp _A , δh _A ) were derived as δd _A = 17, δp _A = 9.5, and δh _A = 12.1, respectively.

Further, regarding the surface modifiers used in Examples 1 to 11 shown in the chemical formulas (1) to (11), the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameter by the surface modification unit is expressed as a molecular group. Calculation was made by the contribution method, and δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A were derived. Table 1 shows the derivation results.

<< Comparative Example 1 >>
A rare earth magnetic powder was produced in the same manner as in Example 1 except that the surface treatment with the surface modifier was not performed. Specifically, in Example 1, the surface modifier is not added, and the blending ratio of the inorganic material, the polymer material, and the additive is 94.25: 5.25: 0. 5 was kneaded to obtain a compound for a bonded magnet.

In addition, the particle diameter when inorganic material powder is dispersed in a plurality of organic solvents with known HSP parameters is measured based on the dynamic light scattering method, and the difference in particle diameter due to the difference in aggregation and dispersion for each solvent. The wettability of the inorganic material was determined, and the HSP parameters (δd _M , δp _M , δh _M ) of the inorganic material (rare earth magnetic powder) were measured. Specifically, a solvent whose average particle size was within twice the average particle size of the inorganic material powder was evaluated as having good wettability. Solvents that have been determined to have good wettability are contained inside the sphere, and the solvent that has not been determined to have good wettability is outside the sphere, and the Hansen sphere having the smallest radius is obtained. The HSP parameters (δd _M , δp _M , δh _M ) of the material (rare earth magnetic powder) were derived as δd _M = 16.8, δp _M = 7.7, and δh _M = 2.2, respectively.

<< Comparative Example 2 >>
A rare earth magnetic powder was produced in the same manner as in Example 1 except that a material represented by the following chemical formula (29) was used as the surface modifier.

<< Comparative Example 3 >>
A rare earth magnetic powder was produced in the same manner as in Example 1 except that a material represented by the following chemical formula (30) was used as the surface modifier.

In the chemical formulas (29) and (30), the portion of the trimethoxysilane group (—Si (OCH ₃ ) ₃ ) is the reaction portion R with the surface of the inorganic material, and the portion other than this is the surface modification portion Q. . As in Examples 1 to 11, regarding the surface modifiers represented by the chemical formulas (29) and (30), the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameter by the surface modification portion is the molecular group contribution. Δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A were derived.

Table 1 shows differences in HSP parameters between the surface modified portion and the polymer material in Examples 1 to 11 and Comparative Examples 1 to δd _SQ −δd _A , δp _SQ −δp _A , and δh. The value of _SQ- δh _A is shown. The unit of the HSP parameter is (J / cm ³ ) ^1/2 . The same applies to the tables shown below. In Comparative Example 1, since no surface modifier is used, instead of the HSP parameters (δd _SQ , δp _SQ , δh _SQ ) of the surface modified portion, the HSP parameters (δd _M , δp _M ) of the inorganic material are used. , Δh _M ) was used. As can be seen from Table 1, in Examples 1 to 11, | δd _SQ −δd _A | ≦ 3 (J / cm ³ ) ^1/2 , | δp _SQ −δp _A | ≦ 3 (J / cm ³ ) ^{1 / 2} and | δh _SQ −δh _A | ≦ 3 (J / cm ³ ) ^1/2 are satisfied, but Comparative Examples 1 to 3 do not satisfy all the above conditions.

  Moreover, it replaced with the polyamide resin of Examples 1-11 as a polymeric material, the surface modification inorganic powder 4 using LCP resin was produced, and the compound 5 for bond magnets was produced and evaluated.

<< Examples 12-15 >>
In accordance with the above-described method for preparing rare earth magnetic powder, “MQP-14-12” manufactured by Magnequen Co., Ltd. as an inorganic material (rare earth magnetic powder 1) is treated with a surface modifier, and LCP resin (Ueno Pharmaceutical Co., Ltd.) as polymer material 2 is obtained. "UENO LCP A8100" manufactured by Co., Ltd.) and "Light Amide WH-215" manufactured by Kyoeisha Chemical Co., Ltd. as an additive are added and mixed and kneaded at a predetermined mixing ratio, and the kneaded product is processed into pellets with a pelletizer or the like. The compound 5 for bond magnets was obtained. The blending ratio of the inorganic material, the polymer material, the additive, and the surface modifier was 94.25: 5: 0.5: 0.25 in terms of mass ratio, respectively. The kneading temperature was 250 ° C.

  As the surface modifier, the structures shown in the above chemical formulas (12) to (15) were synthesized and used as the surface modifiers in Examples 12 to 15, respectively. As the structure of the R portion, a trimethoxysilane group represented by the chemical formula (16), a triethoxysilane group represented by the chemical formula (17), or phosphonic acid was appropriately selected.

  About the produced compound for bonded magnets, the viscosity which is a parameter | index of fluidity | liquidity was measured using the capillary rheometer. The viscosity of the bonded magnet compound at 300 ° C. was measured.

  Moreover, the HSP parameter of the polymer material was measured. Since LCP resin does not dissolve in most solvents, the contact angle when various solvents were dropped onto the LCP resin plate was measured to evaluate the wettability with the solvent. The height of the dropped solvent is h, the width is 2r, the contact angle θ is obtained from the relationship of tan θ = h / r, the solvent having a contact angle of 8 ° or less is evaluated as soluble, and the solvent having a contact angle exceeding 8 ° Was evaluated as insoluble. As a result, 2 types of 11 types of solvents were dissolved at room temperature, and the other 9 types were not dissolved. The 11 solvents for which dissolution experiments were performed are shown below, including the results of dissolution / non-dissolution.

  Dissolved solvent: 1-methylnaphthalene, aniline

  Solvents not dissolved: nitrobenzene, 1-bromonaphthalene, benzylbenzoate, quinoline, γ-butyrolactone (GBL), N-methylaniline, dimethyl sulfoxide (DMSO), ethylene glycol, formaldehyde

From this result, the HSP parameter of the polymer material (LCP resin) is obtained by obtaining a Hansen sphere that contains the solvent to be dissolved inside the sphere, the solvent that does not dissolve is outside the sphere, and has the smallest radius. (Δd _A , δp _A , δh _A ) were derived as δd _A = 17.4, δp _A = 17, and δh _A = 19.1, respectively.

Further, regarding the surface modifiers used in Examples 12 to 15 shown in the chemical formulas (12) to (15), the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameter by the surface modification unit is expressed in the molecular group. When calculated by the contribution method and δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A were derived, the results shown in Table 2 were obtained.

<< Comparative Example 4 >>
A rare earth magnetic powder was produced in the same manner as in Example 12 except that the surface treatment was not performed with the surface modifier. Specifically, in Example 12, the surface modifier is not added, and the blending ratio of the inorganic material, the polymer material, and the additive is 94.25: 5.25: 0. 5 was kneaded to obtain a compound for a bonded magnet.

<< Comparative Example 5 >>
A rare earth magnetic powder was produced in the same manner as in Example 12 except that a material represented by the following chemical formula (31) was used as the surface modifier.

<< Comparative Example 6 >>
A rare earth magnetic powder was produced in the same manner as in Example 12 except that a material represented by the following chemical formula (32) was used as the surface modifier.

In the chemical formulas (31) and (32), the portion of the trimethoxysilane group (—Si (OCH ₃ ) ₃ ) is the reaction portion R with the surface of the inorganic material, and the portion other than this is the surface modification portion Q. . In the same manner as in Examples 12 to 15, with respect to the surface modifier represented by the chemical formulas (31) and (32), the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameters by the molecular modification group Calculation was made by the contribution method, and δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A were derived.

Table 2 shows differences in HSP parameters δd _SQ −δd _A , δp _SQ −δp _A , and δh between the surface modified portion and the polymer material in Examples 12 to 15 and Comparative Examples 4 to 6. The value of _SQ- δh _A is shown. However, in Comparative Example 4, since no surface modifier is used, instead of the HSP parameters (δd _SQ , δp _SQ , δh _SQ ) of the surface modified portion, the HSP parameters (δd _M , δp _M ) of the inorganic material are used. , Δh _M ) was used. As can be seen from Table 2, in Examples 12 to 15, | δd _SQ −δd _A | ≦ 3 (J / cm ³ ) ^1/2 , | δp _SQ −δp _A | ≦ 3 (J / cm ³ ) ^{1 / 2} and | δh _SQ −δh _A | ≦ 3 (J / cm ³ ) ^1/2 are satisfied, but Comparative Examples 4 to 6 do not satisfy all the above conditions.

  In Table 3, the result of having measured the viscosity of the compound for bonded magnets about Examples 1-11 and Comparative Examples 1-3 is shown. As shown in Table 3, it can be seen that the compounds for bonded magnets of Examples 1 to 11 have a significantly reduced viscosity and show good fluidity as compared with Comparative Examples 1 to 3.

  In Table 4, the result of having measured the viscosity of the compound for bonded magnets about Examples 12-15 and Comparative Examples 4-6 is shown. As shown in Table 4, it can be seen that the bonded magnet compounds of Examples 12 to 15 have significantly lower viscosities and better fluidity than Comparative Examples 4 to 6.

In Tables 3 and 4, the value of the HSP distance Ra between the surface modified portion Q and the polymer material is shown together with the measurement result of the viscosity. Here, the HSP distance Ra in Table 3 and Table 4 regards the HSP parameters (δd _SQ , δp _SQ , δh _SQ ) attributed to the surface modifier Q as the HSP parameters of the surface modifier, and the polymer material HSP distance Ra between is calculated based on Equation 1.

  In both Table 3 and Table 4, the smaller the HSP distance Ra, the lower the viscosity, suggesting that there is some positive correlation between the decrease in HSP distance Ra and the decrease in viscosity.

FIG. 2 is a graph of the results in Table 3. Similarly, FIG. 3 is a graph of the results in Table 4. 2 and 3, it can be seen that there is a linear relationship between the HSP distance Ra and the viscosity. This is a proof that it is effective to evaluate the compatibility with the polymer material based on the contribution (δd _SQ , δp _SQ , δh _SQ ) of the HSP parameter by the surface modification portion.

  The surface-modified inorganic powder according to the present invention includes various materials such as conductive materials, EMC materials, recording materials, magnetic materials, sliding materials, sealing materials, vibration damping materials, dental materials, heat insulating materials, heat conducting materials, buoyancy materials, and the like. It can be used as various functional materials, and can be used as a composite material combined with a polymer material.

  1: rare earth magnetic powder (inorganic material), 2: polymer material, 3: surface modified part, 4: surface modified inorganic powder, 5: compound for bonded magnet (composite material)

Claims (25)

A surface-modified inorganic powder that is a reaction product of an inorganic material and a surface modifier,
The surface modifier has a surface modification portion Q and a reaction portion R with the inorganic material,
The surface-modified inorganic powder includes the inorganic material, and a surface-modified portion Q that covers the surface of the inorganic material,
The surface modification portion Q has a property of being compatible with a polymer material to be compatible with,
Contributions by the surface modification part Q in the Hansen solubility parameters δd _S , δp _S , δh _S of the surface modifier δd _SQ , δp _SQ , δh _SQ, and Hansen solubility parameters δd _A , δp _A , Each of the differences δd _SQ −δd _A , δp _SQ −δp _A , and δh _SQ −δh _A within the range of ± 3 (J / cm ³ ) ^1/2 , respectively, from δh _A Powder. The polymer material has an amide bond,
The δd _SQ is in a range of 14 ≦ δd _SQ ≦ 20;
The δp _SQ is in a range of 6.5 ≦ δp _SQ ≦ 12.5,
The surface-modified inorganic powder according to claim 1, wherein the δh _SQ is in a range of 9.1 ≦ δh _SQ ≦ 15.1.   The surface-modified inorganic powder according to claim 2, wherein the surface modifier is a monocyclic aromatic compound having the reactive portion R and a phenolic hydroxyl group. The surface modifier is represented by the following chemical formula (1):

The surface-modified inorganic powder according to claim 3, represented by: The surface modifier is represented by the following chemical formula (2):

The surface-modified inorganic powder according to claim 3, represented by: The surface modifier is represented by the following chemical formula (3):

The surface-modified inorganic powder according to claim 3, represented by:   The surface-modified inorganic powder according to claim 2, wherein the surface-modified portion Q has an ethylene group.   The surface-modified inorganic powder according to claim 2, wherein the surface-modified portion Q has a vinylene group.   The surface-modified inorganic powder according to claim 7 or 8, wherein the surface-modified portion Q has a carboxyl group.   The surface-modified inorganic powder according to any one of claims 7 to 9, wherein the surface-modified portion Q has an amino group.   The surface-modified inorganic powder according to any one of claims 7 to 10, wherein the surface-modified portion Q has a thiol group. The surface modifier is represented by the following chemical formula (4):

The surface-modified inorganic powder according to claim 7, represented by: The surface modifier is represented by the following chemical formula (5):

The surface-modified inorganic powder according to claim 7, represented by: The surface modifier is represented by the following chemical formula (6):

The surface-modified inorganic powder according to claim 7, represented by: The surface modifier is represented by the following chemical formula (7):

The surface-modified inorganic powder according to claim 7, represented by: The surface modifier is represented by the following chemical formula (8):

The surface-modified inorganic powder according to claim 7, represented by: The surface modifier is represented by the following chemical formula (9):

The surface-modified inorganic powder according to claim 8, represented by: The surface modifier is represented by the following chemical formula (10):

The surface-modified inorganic powder according to claim 8, represented by: The surface modifier has the following chemical formula (11):

The surface-modified inorganic powder according to claim 8, represented by:   20. The reaction part R has an alkoxy group, and the alkoxy group reacts with the inorganic material to form a binding site between the inorganic material and the surface modification portion Q. The surface-modified inorganic powder according to claim 1.   The surface-modified inorganic powder according to any one of claims 1 to 20, wherein the surface modifier includes a silane coupling agent or a titanate coupling agent. The surface modifier comprises an organic phosphonic acid having a hydroxyl group in the reaction portion R;
The surface according to any one of claims 1 to 19, wherein the hydroxyl group in the organic phosphonic acid reacts with the inorganic material to form a binding site between the inorganic material and the surface modification portion. Modified inorganic powder. The δd _SQ , the δp _SQ , and the δh _SQ are respectively the Hansen solubility parameters δd _S , δp _S , and δh _S of the surface modifier calculated by the molecular group contribution method. The surface-modified inorganic powder according to any one of claims 1 to 22, which is obtained by deriving a contribution from a molecular group constituting the same.   The surface-modified inorganic powder according to any one of claims 1 to 23, wherein the inorganic material is a magnetic material.   The magnetic material includes at least one selected from the group consisting of Nd-Fe-B based magnetic powder, Sm-Fe-N based magnetic powder, Sm-Co based magnetic powder, and ferrite based magnetic powder. Item 25. The surface-modified inorganic powder according to Item 24.

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