阅读说明：本技术 复合粒子材料和其制造方法、复合粒子材料浆料、树脂组合物 (Composite particle material, method for producing same, composite particle material slurry, and resin composition ) 是由 恩田宽之 富田亘孝 新井雄己 于 2018-05-17 设计创作，主要内容包括：本发明的应解决的课题在于提供一种将无机物粒子材料均匀且牢固地接合于树脂粒子材料的表面的用于布线密封材料的复合粒子材料的制造方法。通过使由氟树脂构成的树脂粒子材料与无机物粒子材料熔接,从而能够均匀且牢固地接合。本发明的复合粒子材料的制造方法具有熔接工序,其将树脂粒子材料和无机物粒子材料以漂浮于由气体和/或液体构成的介质中的状态投入到所述树脂粒子材料的玻璃化转变点或软化点以上的高温气氛下,使无机物粒子材料熔接于所述树脂粒子材料的表面。通过使无机物粒子材料熔接于树脂粒子材料的表面,从而能够实现牢固的接合。由于即使不施加外力也会进行熔接,因此,树脂粒子材料与无机物粒子材料能够以混合后的均匀的状态熔接。由于树脂粒子材料与无机物粒子材料的混合物以漂浮于介质中的状态投入到高温气氛下,因此,树脂粒子材料间的熔接·凝聚不易进行。(The problem to be solved by the present invention is to provide a method for producing a composite particle material for a wiring sealing material, in which an inorganic particle material is uniformly and firmly bonded to the surface of a resin particle material. The resin particle material made of fluororesin and the inorganic particle material are fused together, whereby uniform and strong bonding can be achieved. The method for producing a composite particulate material of the present invention includes a welding step of putting a resin particulate material and an inorganic particulate material in a state of floating in a medium composed of a gas and/or a liquid into a high-temperature atmosphere of a glass transition point or a softening point or higher of the resin particulate material, and welding the inorganic particulate material to the surface of the resin particulate material. By fusing the inorganic particle material to the surface of the resin particle material, strong bonding can be achieved. Since the resin particle material and the inorganic particle material are fused together without applying an external force, the resin particle material and the inorganic particle material can be fused together in a uniform state after mixing. Since the mixture of the resin particle material and the inorganic particle material is put in a high-temperature atmosphere in a state of floating in the medium, the fusion and aggregation between the resin particle materials are not easily performed.)

1. A composite particle material comprising a resin particle material and an inorganic particle material having a smaller particle diameter than the resin particle material and fused to the surface of the resin particle material, wherein the composite particle material satisfies the following conditions (a), (b), and (c):

(a) the sphericity of the spherical particles is 0.8 or more,

(b) the volume average particle diameter is 0.1 to 100 μm,

(c) the inorganic particle material is formed of an inorganic oxide and has OH groups on the surface thereof, which are generated by fusion bonding.

2. The method of claim 1The composite particle material of (1), wherein the amount of OH groups on the surface of the inorganic particle material is 0.1 to 30. mu. mol/m²。

3. The composite particle material according to claim 2, wherein said composite particle material is treated with at least one or more of a silane compound, an organosilazane, and an organic compound having an amino group.

4. The composite particle material according to any one of claims 1 to 3, wherein no sea-island structure is observed when the slurry dispersed in methyl ethyl ketone at a concentration of 20% by mass is observed with an optical microscope.

5. The composite particulate material according to any one of claims 1 to 4, wherein the content of the inorganic particles is 1mg/m after mixing 100g of the composite particulate material with 200mL of methyl ethyl ketone and repeating the washing operation of the following (A) 3 times²In the above-mentioned manner,

(A) after 5 minutes of ultrasonic wave irradiation, the precipitate was collected by centrifugation at 10000rpm for 5 minutes under conditions of 40kHz and 600W.

6. The composite particulate material according to any one of claims 1 to 5, wherein the cleaning of (A) is repeated 3 times and the cleaning is redispersible in methyl ethyl ketone.

7. The composite particulate material of any one of claims 1 to 6, wherein the linseed oil absorption is 30g/100g or less.

8. A composite particulate material slurry having:

the composite particle material of any one of claims 1 to 7, and

an organic solvent in which the composite particle material is dispersed.

9. A resin composition containing a composite particle material, comprising:

the composite particle material of any one of claims 1 to 7, and

a resin material before polymerization in which the composite particle material is dispersed.

10. A method for producing a composite particle material, characterized by comprising a welding step in which a resin particle material and an inorganic particle material are put in a state of floating in a medium composed of a gas and/or a liquid into a high-temperature atmosphere composed of a gas having a glass transition point or a softening point or higher of the resin particle material, the inorganic particle material is welded to the surface of the resin particle material, and OH groups are generated on the surface of the inorganic oxide particle material by the welding step.

11. The method for producing a composite particle material according to claim 10, wherein the inorganic oxide particle material having a degree of hydrophobization of 20 or more is used.

12. The method for producing a composite particulate material according to claim 10 or 11, wherein the inorganic particulate material has a surface to which a compound represented by formula (1): -OSiX¹X²X³A functional group shown and formula (2): -OSiY¹Y²Y³The functional groups shown are inorganic particles of two functional groups,

in the formulae (1) and (2), X¹Is phenyl, vinyl, epoxy, methacrylate, amino, ureido, mercapto, isocyanate or acrylate, X²、X³Each independently selected from-OSiR₃and-OSiY⁴Y⁵Y⁶，Y¹Is R, Y²、Y³Each independently selected from R and-OSiY⁴Y⁵Y⁶，Y⁴Is R, Y⁵And Y⁶Each independently selected from R and-OSiR₃R is independently selected from alkyl with 1-3 carbon atoms, and X²、X³、Y²、Y³、Y⁵And Y⁶Any of which may be related to X of an adjacent functional group²、X³、Y²、Y³、Y⁵And Y⁶Any of which is bonded with-O-.

13. The method for producing a composite particulate material according to any one of claims 10 to 12, wherein in the welding step, the resin particulate material is brought into contact with the high-temperature atmosphere until the sphericity of the obtained composite particulate material becomes 0.8 or more.

14. The method for producing a composite particle material according to any one of claims 10 to 13, wherein in the welding step, a sea-island structure is not observed when the obtained composite particle material is dispersed in 20 mass% in a slurry of methyl ethyl ketone by observation with an optical microscope.

Technical Field

The present invention relates to a composite particle material used by mixing with a resin composition for electronic materials, which is formed by fusing an inorganic particle material to the surface of a particle material made of a resin, a method for producing the composite particle material, and a composite particle material slurry and a resin composition containing the composite particle material.

Background

Conventionally, for the purpose of improving electrical characteristics, dimensional stability after curing, and the like by adding different materials, use of a particle material composed of a resin (referred to as "resin particle material" in the present specification) as a filler in a resin composition before curing (resin composition before curing) has been carried out. For example, a fluororesin having a C — F bond is used for improving electrical characteristics.

In general, many resin particle materials have low affinity with organic solvents, organic materials, and the like, and surface modification is not easy.

The present applicant has therefore proposed a composite particle material in which the surface of a resin particle material (made of polytetrafluoroethylene, PTFE) is coated with an inorganic particle material made of silica (patent document 1). The inorganic material constituting the inorganic particle material is easily provided with a desired performance by surface treatment with a silane coupling agent or the like, and is expected to have an effect of improving the affinity with the mixed resin composition before curing.

Disclosure of Invention

However, although the composite particle material disclosed in patent document 1 can improve dispersibility in a solvent or the like, since the inorganic particle material is pressed by an external force and embedded in the surface of the resin particle material, unnecessary stress may remain in the obtained composite particle material. Further, it was found that the inorganic particle material and the resin particle material were not sufficiently bonded to each other because they were merely pressed and embedded, and the adhesion to the resin composition was poor. As a result, it is found that when the metal is used for electronic material applications, the affinity with the metal used for wiring is reduced.

The present invention has been made in view of the above circumstances, and an object to be solved by the present invention is to provide a composite particle material in which an inorganic particle material is uniformly and firmly bonded to the surface of a resin particle material, and a method for producing the same.

As a result of intensive studies to solve the above problems, the present inventors have found that by welding a resin particle material and an inorganic particle material, OH groups having an effect of improving the affinity with a metal and the like can be generated on the surface of the inorganic particle material while uniformly and firmly bonding the resin particle material and the inorganic particle material to each other, and have completed the following invention.

(1) The method for producing a composite particulate material according to the present invention for solving the above problems is characterized by comprising a welding step of putting a resin particulate material and an inorganic particulate material in a state of floating in a medium composed of a gas and/or a liquid into a high-temperature atmosphere of a glass transition point or a softening point or higher of the resin particulate material, and welding the inorganic particulate material to the surface of the resin particulate material. The welding step is a condition under which OH (hereinafter, sometimes referred to as "surface OH group") is generated on the surface of the inorganic particle material. The composite particle material produced by the production method of the present invention is suitable for mixing with a resin composition for electronic materials used in contact with a metal wiring.

The surfaces of the resin particle materials are softened or melted to weld the inorganic particle materials, thereby achieving strong bonding. Since the resin particle material and the inorganic particle material are welded to each other without applying an external force, the resin particle material and the inorganic particle material can be joined to each other by welding while maintaining a uniform state after mixing. Since the resin particle materials and the inorganic particle materials are put in a high-temperature atmosphere in a state of floating in the medium, the resin particle materials are not easily fused and aggregated.

(2) As a result of analysis and study of the composite particulate material produced by the method of the present invention, the following composite particulate materials were invented. That is, the composite particle material of the present invention for solving the above problems is characterized by comprising a resin particle material and an inorganic particle material having a smaller particle diameter than the resin particle material and fused to the surface of the resin particle material. The composite particle material of the present invention satisfies the following conditions (a), (b), and (c). (a) A sphericity of 0.8 or more, (b) a volume average particle diameter of 0.1 to 100 [ mu ] m, and (c) the inorganic particle material is formed of an inorganic oxide and has OH groups on the surface thereof, which are generated by fusion bonding.

The composite particle material of the present invention is suitably used as a mixture with a resin composition for electronic materials used in contact with metal wiring.

Since the inorganic particle material is fused to the surface of the resin particle material, even when dispersed in a solvent, a resin composition before curing (and a resin composition before curing after curing), or the like, the inorganic particle material is less likely to fall off, and aggregation and fiberization due to the resin particles can be suppressed, so that aggregation of the composite particle material is less likely to occur. Further, when the resin composition is dispersed in the resin composition before curing to form the resin composition and is cured in a state of being in contact with a member made of a metal such as a copper material and used, the adhesion after curing is excellent.

In the inventions disclosed in (1) and (2), the particle diameter of the inorganic particle material used is preferably 1/10 to 1/10000, more preferably 1/50 to 1/5000, with respect to the particle diameter of the resin particle material. When the amount is within this range, the inorganic particle material can be more uniformly arranged on the surface of the resin particle material.

Further, it is preferable that no sea-island structure is observed when a slurry dispersed in methyl ethyl ketone at a concentration of 20 mass% is observed with an optical microscope. In the discrimination of the sea-island structure, the concentration of 40 mass% or 60 mass% may be used instead of 20 mass%. When the result of discrimination by 40 mass% or 60 mass% is different from the result of discrimination by 20 mass%, the result of 20 mass% is prioritized. In the case of the composite particle material in which the sea-island structure is not observed, the inorganic particle material is uniformly attached to the surface of the resin particle material. Since the inorganic particle material uniformly adheres to the surface of the resin particle material, the inorganic particle material uniformly acts on the particles constituting the composite particle material, and is not easily aggregated and uniformly dispersed in methyl ethyl ketone, and therefore, a sea-island structure is not observed. The judgment as to whether "no sea-island structure is observed" is described in detail in the embodiment.

The resin particle material is preferably composed of a fluororesin. Although the fluororesin has low affinity for the solvent and the resin composition before curing and tends to aggregate in this state, the composite particle material firmly coated with the inorganic particle material can suppress the generation of aggregates.

The inorganic particle material is preferably surface-treated with a silane coupling agent. By surface-treating with a silane coupling agent having an appropriate functional group, the adhesiveness to the surface of the welded resin material is improved, and the affinity with the solvent in which the obtained composite particle material is mixed and dispersed and the resin composition before curing can be improved, whereby the aggregation can be effectively suppressed, and the bond at the time of curing the resin composition before curing can be made strong.

In the welding step, the resin particle material is preferably brought into contact with the high-temperature atmosphere until the sphericity of the composite particle material obtained becomes 0.8 or more. The resin particle material is exposed to a high-temperature atmosphere to release stress and thereby approach a spherical shape, and therefore, the sphericity can be improved.

The composite particulate material and the method for producing the same according to the present invention have the above-described configuration, and can provide a composite particulate material in which an inorganic particulate material is firmly bonded to the surface of a resin particulate material. In particular, the inorganic particle material can be uniformly arranged on the surface of the resin particle material. As a result of uniformly and firmly bonding the inorganic particle materials, for example, when constituting a slurry, low viscosity, low dielectric characteristics, and high adhesion can be achieved.

Drawings

FIG. 1 is a photograph showing the dispersion state of the slurry dispersion of example 1 observed with an optical microscope in examples.

FIG. 2 is a photograph showing the dispersion state of the slurry dispersion of comparative example 2 observed by an optical microscope in examples.

Fig. 3 is a photograph showing the state of dispersion of the slurry dispersion prepared after washing the composite particle material of example 1, by an optical microscope.

Fig. 4 is an IR spectrum of the surface measured after cleaning the composite particle material of example 1.

Fig. 5A is an SEM photograph (2000 ×) of the test specimen of example 1 in example.

Fig. 5B is an SEM photograph (50000 times) of the test specimen of example 1 in example.

Fig. 6A is an SEM photograph (1000 ×) of the test sample of comparative example 1 in example.

Fig. 6B is an SEM photograph (3000 times) of the test sample of comparative example 1 in example.

Fig. 6C is an SEM photograph (1000 ×) of the test sample of comparative example 3 in example.

Fig. 6D is an SEM photograph (3000 times) of the test sample of comparative example 3 in example.

Fig. 7 is a photograph showing a cross-sectional TEM image of the composite particle material of example 1.

Fig. 8 is an IR spectrum of the composite particle materials of examples 1 and 22.

FIG. 9 shows IR spectra of composite particle materials of examples 1 and 17 to 20.

Detailed Description

The composite particle material and the method for producing the same according to the present invention will be described in detail based on the following embodiments. The composite particulate material of the present embodiment can be used as a filler dispersed in a resin composition before curing. The properties of the resin material contained in the composite particle material can be imparted to the dispersed resin composition before curing. For example, when a composite particle material containing a fluororesin having a low dielectric constant is added to a resin composition before curing, the dielectric constant of the added resin composition before curing can be reduced. Further, by adding and dispersing the composite particle material of the present embodiment to a resin composition before curing composed of a monomer, a resin precursor, or the like, shrinkage accompanying curing of the resin composition before curing can be suppressed, and a precise member can be manufactured. Examples of the resin composition before curing to which the composite particle material of the present embodiment can be added and dispersed include a precursor of a thermosetting resin material (an epoxy resin, a polyester resin, a urea resin, a silicone resin, etc.; a material before curing, a material that is partially cured but has fluidity), a monomer of a thermoplastic resin (a polyphenylene ether resin, a modified polyphenylene ether resin, a polyimide resin, a liquid crystal polymer resin, etc.), and a melt obtained by heating and melting the thermoplastic resin. The composite particle material of the present embodiment has excellent adhesion to the metal constituting the wiring, and therefore can be used by being mixed with a resin composition for an electronic material used in contact with the metal wiring.

The composite particle material of the present embodiment includes a resin particle material and an inorganic particle material. The inorganic particle material is fused to the surface of the resin particle material. The presence ratio of the inorganic particle material to the resin particle material is not particularly limited. The inorganic particle material is fused to the surface, thereby modifying the surface of the resin particle material. In addition to the composite particle material, a free inorganic particle material or a resin particle material may be present. The particle diameter of the composite particle material of the present embodiment is 0.1 to 100. mu.m. In particular, when the resin composition is used while dispersed in the resin composition, it is preferable that particles (coarse particles) having a particle size larger than the smallest gap of a portion filled with the resin composition are substantially not contained (for example, the upper limit of the content of the coarse particles is preferably 1000ppm, 500ppm, 200ppm, 100ppm, 50 ppm). For example, in the case of a resin composition filled in a 50 μm gap, coarse particles having a particle size of 50 μm or more are preferably 1000ppm or less, more preferably 500ppm or less, and still more preferably 200ppm or less.

The inorganic particle material is preferably uniformly arranged on the surface of the resin particle material. Whether the slurry is uniformly arranged or not can be judged by the sea-island structure in the slurry state.

The presence or absence of the sea-island structure was observed by an optical microscope using a slurry prepared by dispersing the composite particle material of the present embodiment in methyl ethyl ketone at 20 mass%. Since the sea-island structure is observed from the portion composed of methyl ethyl ketone and the portion where the dispersed composite particle material is aggregated, the sea-island structure is not observed if uniformly dispersed. The size of the visual field observed to determine the sea-island structure is about 100 to 1000 times the particle size of the composite particle material. Particularly, the particle diameter of the composite particle material is 200 times.

The resin particle material is a particle made of fluororesin. The resin constituting the resin particle material is a resin that softens or melts when heated. Examples of the fluororesin include, but are not particularly limited to, tetrafluoroethylene (PTFE), Perfluoroalkoxyalkane (PFA), perfluoroethylene-propylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), Polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), tetrafluoroethylene-perfluorobisperfluorobismuthyl

Metallocene copolymer (TFE/PDD), polyvinyl fluoride (PVF). More than 2 kinds may be used.

The particle size of the resin particle material varies depending on the application, and the particle size distribution is not particularly limited, and is selected so that the particle size of the obtained composite particle material falls within the above range. For example, it may be about 0.05 μm to 100. mu.m. When the composite particulate material is used as a filler for an electronic component material, it is also preferable to remove the resin particulate material having a particle diameter of a predetermined size or more. The method of controlling the particle diameter is not particularly limited, and the resin material may be produced by a method of cutting the resin material into fine particles by physical action such as pulverization, or by classification to obtain a resin particle material having a desired particle size distribution, or by emulsion polymerization or suspension polymerization to initially have a desired particle size distribution. The resin particle material is preferably a resin particle material having a high sphericity. The sphericity of the composite particle material of the present embodiment is preferably 0.8 or more, and more preferably 0.85 or more and 0.9 or more. More preferably a spherical composite particle material.

In order to improve the sphericity, a method of adjusting the particle size distribution of the resin material to an appropriate value and then putting the resin material in a high-temperature atmosphere may be employed. The charging into the high-temperature atmosphere may be performed by the same method as the method of charging the resin particle material into the high-temperature atmosphere performed in the welding step of the manufacturing method described later. In the welding step described later, the sphericity can be improved by selecting conditions under which the resin particle material is sufficiently melted.

The inorganic particle material is fused to the surface of the resin particle material. The step of welding (welding step) is performed by performing a treatment at a high temperature under the condition that the inorganic particle material is present on the surface of the resin particle material. By the high temperature treatment, OH groups are generated on the surface of the inorganic particle material. The amount of OH groups present on the surface may be, for example, 0.1 to 30. mu. mol/m². The lower limit of the amount of OH groups is, for example, 0.1. mu. mol/m²、0.5μmol/m²、1μmol/m²The upper limit is, for example, 30. mu. mol/m²、25μmol/m²、20μmol/m². These upper and lower limits may be combined arbitrarily, and when they fall within these ranges, the adhesion is improved.

The treatment temperature in the welding step is a temperature at which at least a part of the surface of the resin particle material can be melted. For example, the temperature is a temperature equal to or higher than the softening point, and further equal to or higher than the melting point of the resin material constituting the resin particle material. In addition, the temperature at which OH groups are generated on the surface of the inorganic particle material is used. For example, when silica is used as the inorganic particle material, it is preferably 400 ℃ or higher, and when alumina is used, it is preferably 400 ℃ or higher.

The fusion bonding is a state in which a part of the surface of the resin particle material is deformed in accordance with the outer shape of the inorganic particle material. In particular, when the content of the inorganic particles measured by the method described later in the composite particle material becomes a predetermined value or more, it can be determined that the welding is reliably performed. The predetermined value may be set to 1mg/m²、3mg/m²、5mg/m²、10mg/m²、50mg/m²The predetermined value is particularly preferably a large value. It is preferable that the sea-island structure under the above-described conditions is not observed even after 3 times of washing operations in the method of measuring the content of inorganic particles described later (in this case, it is judged to be redispersible).

The inorganic particle material has a smaller particle diameter than the resin particle material. The inorganic material constituting the inorganic particle material is not particularly limited, and examples thereof include inorganic oxides such as silica, alumina, zirconia, and titania, and composite oxides thereof. The inorganic particle material may contain an organic material. Examples thereof include particles such as silicone oil, an aqueous solution of silicic acid, an aqueous solution of tetraethyl orthosilicate, and silicone resin. The inorganic particle material has a smaller particle diameter than the resin particle material. The method for controlling the particle size of the inorganic particle material is not particularly limited, and the inorganic particles may be formed into a desired particle size distribution by a combination of mechanical methods such as pulverization and classification, or formed into particles by a method in which inorganic materials constituting the inorganic particle material are synthesized by a sol-gel method, a hydrothermal method, or the like.

The particle size of the inorganic particle material is preferably 1/10 to 1/10000, more preferably 1/50 to 1/5000, based on the particle size of the resin particle material. Specific numerical values are exemplified, and the lower limit values of the particle diameters include 1nm, 3nm, 5nm, 10nm, 15nm, 20nm, 30nm, 50nm, 80nm and 100nm, and the upper limit values thereof include 1 μm, 800nm, 500nm, 300nm, 200nm, 150nm and 100 nm.

The inorganic particle material may be surface-treated with a silane compound having an Si — H bond. In addition, the surface treatment may be performed after the composite particle material is produced. The silane compound further includes a silane coupling agent, silazanes, and silicones (substances having an organopolysiloxane structure in the molecule). The silane compound is preferably a compound having a phenyl group, a vinyl group, an epoxy group, a methacrylic group, an amino group, a phenylamino group, a ureido group, a mercapto group, an isocyanate ester, an acrylic group, a fluoroalkyl group, or an alkyl group. Among the silane compounds, examples of silazanes include 1,1,1,3,3, 3-hexamethyldisilazane. In addition, surface treatment may be performed using titanates or aluminates. The surface treatment may be performed for the purpose of improving the affinity with the resin particle material described above, or for the purpose of improving the affinity with a target material (resin material, solvent, or the like) to which the composite particle material of the present embodiment is used. The surface treatment with the silane compound is preferably an amount such that all OH groups present on the surface of the inorganic particle material can be reacted, but OH groups may remain.

Method for producing composite particle material

The method for producing a composite particulate material according to the present embodiment is a method capable of suitably producing the composite particulate material according to the present embodiment described above. The method for producing a composite particle material of the present embodiment includes a welding step and other steps that are used as necessary.

The welding step is a step of welding the inorganic particle material, which is softened by the resin particle material and attached to the surface, to the resin particle material. The temperature at which the resin particle material softens is a melting point, but a glass transition point and a softening point which are temperatures equal to or lower than the melting point may be used. The inorganic particle material and the resin particle material are charged in a high-temperature atmosphere at a temperature higher than these temperatures. The particularly preferred temperature is as described above.

The high temperature atmosphere is formed of a gas. The gas that can be used is not particularly limited, and air, oxygen, nitrogen, argon, or the like can be used. As the inorganic particle material and the resin particle material, the same materials as those usable for the composite particle material of the present embodiment described above can be used, and therefore, further description thereof will be omitted.

The inorganic particle material and the resin particle material may be added together as a mixture in advance, or may be added separately. The inorganic particle material is embedded in advance on the surface of the resin particle material by a mechanochemical method such as a composite chemical device or a pulverizing device before the welding step, whereby the bond between the resin particle material and the inorganic particle material in the subsequent welding step can be made strong. If the inorganic particle material is embedded on the surface of the resin particle material by a mechanochemical method, the resin particle material may be strained, but the strain generated can be eliminated by heating the resin material to a temperature at which the resin material softens in the welding step.

The method for realizing the high-temperature atmosphere is not particularly limited, and a gas (air, oxygen, nitrogen, argon, or the like) constituting the atmosphere may be heated and used. The heating method is not particularly limited, and flame or electrical methods may be used.

For example, as a heat source for the heating method, a flame generated by burning a combustible gas such as propane, town gas, or acetylene can be used. Further, a flame produced by burning a mist or vaporized steam sprayed with an organic solvent such as ethanol, octane, or kerosene may be used. The heating may be performed by direct contact with the flame formed in this manner, or may be performed indirectly by using high-temperature air obtained by heating air with a flame. Specific examples of the combustion device include a premix burner, a diffusion combustion burner, and a liquid fuel burner. For example, as a commercially available apparatus, there can be used a Nanocreator FCM (manufactured by HOSOKAWA MICRON) or an apparatus such as a high-frequency induction thermal plasma nanoparticle synthesis apparatus TP-40020NPS (manufactured by japan electronics). Further, gases heated by using an electric heater such as an air flow Dryer HIRAIWA TurboJet Dryer (manufactured by the flatrock ironman), a Flash Jet Dryer (manufactured by Seishin corporation), a metor Rainbow (manufactured by the PNEUMATIC industry, japan), a micro spray Dryer for high temperature drying (manufactured by kawasaki motor), and the like can be used as a heat source.

When the inorganic particle material and the resin particle material are introduced in a high-temperature atmosphere, the inorganic particle material and the resin particle material are preferably introduced in a dispersed state so that the individual particles are not fused to each other. As a method of dispersing and charging the particles, a method of floating in a medium composed of gas or liquid is employed. The gas and liquid may also be used in combination. If the medium is a liquid, aggregation of particles generated before charging can be suppressed, and therefore, fusion of the resin particle materials can be effectively prevented.

In addition, the "introduction of the inorganic particle material and the resin particle material into the high-temperature atmosphere" may be achieved by preparing the high-temperature atmosphere and introducing the inorganic particle material and the resin particle material therein, or may be achieved by forming the high-temperature atmosphere by raising the temperature of the medium after forming a state in which the inorganic particle material and the resin particle material are floated in the medium (for example, a state in which a fluidized layer is formed).

In the welding step, the resin particle material and the inorganic particle material are exposed to a high-temperature atmosphere until the inorganic particle material is welded to the surface of the resin particle material and OH groups are generated on the surface of the inorganic particle material. Whether or not the fusion is performed may be determined by whether or not at least a part of the surface of the resin particle material contained is softened, or may be determined by a state in which the sea-island structure is not observed when the composite particle material in a slurry state is observed by the above-described method. When the temperature of the high-temperature atmosphere is higher than the melting point of the resin material constituting the resin particle material, it is determined that the inorganic particle material is fused to the surface of the resin particle material. In particular, the time of exposure to a high-temperature atmosphere in the welding step may be set so that the value of the content of the inorganic particles measured by the method described later with respect to the produced composite particle material becomes equal to or greater than a predetermined value. The predetermined value may be set to 1mg/m²、3mg/m²、5mg/m²、10mg/m²、50mg/m²The predetermined value is particularly preferably a large value. In addition, in the welding process, the amount of OH groups generated is not particularly limited, but is preferably 0.1 to 30. mu. mol/m based on the surface area of the inorganic particle material²Within the range of (1). Further preferable upper limit and lower limit of the amount of OH groups may be the above values, and may be combined arbitrarily.

In the welding step, the resin particle material and the inorganic particle material may be brought into contact with each other in a high-temperature atmosphere for a time equal to or longer than a time for heating the resin particle material to form a spherical shape. If the heating time is long, the resin particle material is heated to be softened and melted, and the softened and melted resin particle material can be made spherical by surface tension or the like. The sphericity of the composite particulate material produced by the production method of the present embodiment is preferably 0.8 or more, and more preferably 0.85 or more and 0.9 or more. More preferably, the composite particle material has a high sphericity.

Method for measuring sphericity and method for measuring content of inorganic particles

The sphericity of the composite particle material is calculated by using an image observed by a Scanning Electron Microscope (SEM) on a computer using image analysis software ("ImageJ" and (National Institutes of health, USA) and is a photograph in which about 100 pieces of each composite particle material can be observed on the SEM, and the area and the perimeter of the particle observed therefrom are calculated as a value calculated from (sphericity) {4 pi × (area)/(perimeter) 2 }. the closer to 1 the sphere, and the average value thereof is used.

The composite particulate material developed this time can be used as a raw material for granules of a compression molded product after melt-kneading using a kneader or the like.

The content of the inorganic particles was calculated by the following method. The composite particle material was mixed with 100g of methyl ethyl ketone (200 mL), irradiated with ultrasonic waves (40kHz, 600W) for 5 minutes, centrifuged at 10000rpm for 5 minutes to collect the supernatant, and the washing operation was repeated 3 times to dry the supernatant collected liquid. The residue after drying is mostly an inorganic particulate material, and is considered to be a material that is detached from the surface of the composite particulate material by the above-described cleaning operation. The inorganic particle content was calculated from the following formula, assuming that all of the added inorganic particle materials were fixed or physically adsorbed to the resin particle materials.

Fixing amount [ g ] -addition amount [ g ] -residue after drying (physical adsorption amount) [ g ]

Content of inorganic particles [ mg/m ]²]Fixation amount [ g]/{ (specific surface area after cleaning [ m)²/g]×100[g])}

Here, the drying conditions were carried out at 180 ℃ for 1 hour. The specific surface area was measured by the BET method using nitrogen.

Degree of hydrophobization

The hydrophobization degree of the composite particle material of the present embodiment is preferably 20 or more, more preferably 30 or more, and further preferably 40 or more.

The determination method comprises the following steps: a stirrer was placed in the flask, and 50ml of ion-exchanged water was measured to gently float a sample of 0.2g on the water surface. The stirrer was rotated and methanol was added dropwise gently so as not to directly contact the sample. The hydrophobization degree was calculated from the amount of methanol when all samples were precipitated from the water surface.

(degree of hydrophobization:%) 100 × (methanol addition amount (mL))/(50 mL + methanol addition amount (mL))