Composite particles, method for producing composite particles, liquid composition, method for producing a laminate, and method for producing a film

Abstract

An object of the present invention is to provide composite particles that contain an arbitrary amount of inorganic substances and have desired physical properties such as high polarity. The composite particles of the present invention contain a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320°C and an inorganic substance, and the tetrafluoroethylene-based polymer is at least one selected from a tetrafluoroethylene-based polymer having a polar functional group containing a unit based on perfluoro(alkyl vinyl ether), and a tetrafluoroethylene-based polymer having no polar functional group and containing 2.0 to 5.0 mol% of units based on perfluoro(alkyl vinyl ether) relative to all units.

Description

Technical Field

[0001] The present invention relates to composite particles containing a specified tetrafluoroethylene-based polymer and an inorganic substance, a method for producing the same, a method for producing a liquid composition using the composite particles, a method for producing a laminate, and a method for producing a film. Background Art

[0002] As composite particles of silica and a tetrafluoroethylene-based polymer, the methods of Patent Document 1 and Patent Document 2 are known. However, since the tetrafluoroethylene-based polymer has extremely low polarity and low affinity with other components, it is difficult to highly interact with silica. Therefore, it is difficult to incorporate a sufficient amount of silica into the composite particles of the above documents.

[0003] In addition, since the interaction between silica and the tetrafluoroethylene-based polymer in the composite particles of the above documents is low, their own stability is insufficient, and silica is likely to fall off from the composite particles. Therefore, it is necessary to ensure the interaction between silica and the tetrafluoroethylene-based polymer, and the selection range of silica (such as the amount of hydroxyl groups of silica) is easily restricted.

[0004] Furthermore, due to this limitation, the use form of the composite particles of the above documents is also restricted. For example, it is difficult to improve the affinity of the composite particles for a liquid medium, and foaming is severe when formulating a liquid composition in which the composite particles are dispersed, and it is difficult to ensure its dispersion stability.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-124729

[0008] Patent Document 2: International Publication No. 2018 / 212279 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] After earnest discussions, the present inventors found that if a specified tetrafluoroethylene-based polymer is used, the above technical problems can be solved, and thus the present invention has been completed.

[0011] An object of the present invention is to provide composite particles having desired physical properties such as high polarity while containing an arbitrary amount of an inorganic substance.

[0012] Technical Solution for Solving the Technical Problem

[0013] <1>Composite particles, which contain a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320°C and an inorganic substance, and the tetrafluoroethylene-based polymer is at least one selected from a tetrafluoroethylene-based polymer having a polar functional group containing units based on perfluoro(alkyl vinyl ether), and a tetrafluoroethylene-based polymer without a polar functional group containing 2.0 to 5.0 mol% of units based on perfluoro(alkyl vinyl ether) relative to all units.

[0014] <2>The composite particles as described in <1> above, wherein the powder dynamic friction angle of the composite particles is 40 degrees or less.

[0015] <3>The composite particles as described in <1> or <2> above, wherein the inorganic substance is silica or boron nitride.

[0016] <4>The composite particles as described in <1> to <3> above, wherein the composite particles are spherical or flaky.

[0017] <5>The composite particles as described in any one of <1> to <4> above, wherein the tetrafluoroethylene-based polymer is the core, and the inorganic substance is present on the surface of the core.

[0018] <6>The composite particles as described in <5> above, wherein the core of the tetrafluoroethylene-based polymer and the inorganic substance are each in particle form, and the average particle size of the core is larger than the average particle size of the inorganic substance.

[0019] <7>The composite particles as described in any one of <5> or <6> above, wherein the ratio of the fluorine element content to the inorganic element content on the surface of the composite particles measured by energy dispersive X-ray spectroscopy is less than 1.

[0020] <8>The composite particles as described in any one of <1> to <4> above, wherein the inorganic substance is the core, and the tetrafluoroethylene-based polymer is present on the surface of the core.

[0021] <9>The composite particles as described in <8> above, wherein the mass of the inorganic substance in the composite particles is greater than the mass of the tetrafluoroethylene-based polymer.

[0022] <10>A method for manufacturing composite particles, which is a method for manufacturing the composite particles as described in any one of <1> to <9> above, wherein the particles of the tetrafluoroethylene-based polymer and the particles of the inorganic substance are collided at a temperature above the melting temperature of the tetrafluoroethylene-based polymer and in a floating state to obtain the composite particles.

[0023] <11>Method for producing composite particles, which is a method for producing the composite particles according to any one of <1> to <9> above, wherein the composite particles are obtained by causing the particles of the tetrafluoroethylene-based polymer and the particles of the inorganic substance to collide in a pressed or sheared state.

[0024] <12>Liquid composition, which contains the composite particles according to any one of <1> to <9> above and a liquid dispersion medium, and the composite particles are dispersed in the liquid dispersion medium.

[0025] <13>The liquid composition according to <12> above, wherein the liquid dispersion medium is at least one liquid compound selected from water, amide, ketone and ester.

[0026] <14>Method for producing a laminate, wherein the liquid composition according to <12> or <13> above is applied to the surface of a substrate layer and heated to form a polymer layer, and a laminate having the substrate layer and the polymer layer is obtained.

[0027] <15>Method for producing a film, wherein the composite particles according to any one of <1> to <9> above and a fluoroolefin polymer are melt-kneaded and then extrusion-molded to obtain a film.

[0028] Effects of the Invention

[0029] According to the present invention, composite particles having high polarity and other desired physical properties while containing an arbitrary amount of inorganic substance can be obtained. In addition, according to the present invention, a liquid composition having good dispersion stability containing the composite particles, and a laminate and a film highly having good characteristics (electrical characteristics, low linear expansion property, etc.) based on the tetrafluoroethylene-based polymer and the inorganic substance can also be obtained. Detailed Description

[0030] "Average particle size (D50)" means the volume-based cumulative 50% diameter of the object (particles) obtained by the laser diffraction / scattering method. That is, the particle size distribution of the object is measured by the laser diffraction / scattering method, and a cumulative curve is obtained with the total volume of the group of object particles as 100%, and the particle diameter at the point where the cumulative volume reaches 50% on this cumulative curve.

[0031] "D90" is the volume-based cumulative 90% diameter of the object measured in the same manner.

[0032] "Dynamic friction angle of powder" is a value obtained by measuring the object according to the measurement method specified in JIS Z 8835:2016.

[0033] "Melting temperature (melting point)" is the temperature corresponding to the maximum value of the melting peak of the polymer measured by differential scanning calorimetry (DSC).

[0034] "Glass transition temperature (Tg)" refers to the value measured by analyzing a polymer by dynamic viscoelasticity measurement (DMA).

[0035] "Viscosity" refers to the value obtained by measuring a liquid composition using a B-type viscometer under the conditions of a rotation speed of 30 rpm at 25°C. The measurement is repeated 3 times, and the average value of the 3 measurement values is taken.

[0036] "Thixotropy ratio" refers to the value (η1 / η2) calculated by dividing the viscosity η1 obtained by measuring a liquid composition under the condition of a rotation speed of 30 rpm by the viscosity η2 obtained by measuring the liquid composition under the condition of a rotation speed of 60 rpm.

[0037] A "unit" in a polymer can be a group of atoms directly formed from a monomer, or a group of atoms whose structure has been partially transformed by treating the obtained polymer with a specified method. The unit based on monomer A contained in the polymer is also simply denoted as "monomer A unit".

[0038] The composite particles of the present invention (hereinafter also denoted as "the present particles") are particles containing a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320°C and an inorganic substance.

[0039] The tetrafluoroethylene-based polymer (hereinafter also denoted as "F polymer") is at least one selected from a polymer (1) having a polar functional group containing a unit based on perfluoro(alkyl vinyl ether) (PAVE) (PAVE unit), and a polymer (2) having no polar functional group containing 2.0 to 5.0 mol% of PAVE units relative to all units.

[0040] The present particles are a composite material of a highly stable F polymer and an inorganic substance that can contain an arbitrary amount of the inorganic substance and can adjust physical properties such as polarity to a desired state. Its mechanism of action is not yet clear, but it is speculated as follows.

[0041] The F polymer not only has good shape stability such as fibril resistance, but also has a highly free conformation in which the molecular motion restriction at the single-molecule level is alleviated. This F polymer easily forms microspherulites at the molecular aggregate level, and a minute uneven structure is easily generated on its surface. Therefore, it is considered that the molecular aggregate of the F polymer (such as a single particle of the F polymer) can stably adhere physically to the inorganic substance without damage to its shape. In addition, it is also considered that the interaction between the adhered inorganic substances further promotes the adhesion of the inorganic substances, stabilizing the composite particles.

[0042] As a result, the present particles have high stability while containing an arbitrary amount of the inorganic substance, in other words, while containing a large amount of the inorganic substance, and highly possess the physical properties of the F polymer and the inorganic substance.

[0043] The F polymer in the present particles is a polymer containing TFE units and PAVE units.

[0044] As PAVE, CF2=CFOCF3, CF2=CFOCF2CF3, and CF2=CFOCF2CF2CF3 (PPVE) are preferred, and PPVE is more preferred.

[0045] The melting temperature of the F polymer is 260 to 320 °C, preferably 285 to 320 °C.

[0046] The glass transition temperature of the F polymer is preferably 75 to 125 °C, more preferably 80 to 100 °C.

[0047] The melt viscosity of the F polymer is preferably 1×10 2 ~1×10 6 Pa·s at 380 °C, and more preferably 1×10 3 ~1×10 6 Pa·s.

[0048] If the melting temperature, glass transition temperature, and melt viscosity of the F polymer are within this range, the above mechanism of action is easily enhanced.

[0049] The polar functional groups possessed by the polymer (1) may be included in the units contained in the polymer or in the end groups of the polymer main chain. As the latter type of polymer, examples include polymers having polar functional groups as end groups derived from polymerization initiators, chain transfer agents, etc., or polymers having polar functional groups obtained by plasma treatment or ionizing radiation treatment.

[0050] If the F polymer is the polymer (1), then in the present particles, the polymer (1) and the inorganic substance are not only easily attached physically but also easily attached chemically, and the above mechanism of action is easily enhanced.

[0051] As polar functional groups, hydroxyl group-containing groups, carbonyl group-containing groups, and phosphonyl group-containing groups are preferred. From the viewpoint of easily improving physical properties such as the dispersibility of the present particles, hydroxyl group-containing groups and carbonyl group-containing groups are preferred, and carbonyl group-containing groups are more preferred.

[0052] As the hydroxyl group-containing group, a group containing an alcoholic hydroxyl group is preferred, and -CF2CH2OH, -C(CF3)2OH, and 1,2-ethylene glycol group (-CH(OH)CH2OH) are more preferred.

[0053] As the carbonyl group-containing group, carboxyl group, alkoxycarbonyl group, amide group, isocyanate group, carbamate group (-OC(O)NH2), acid anhydride residue (-C(O)OC(O)-), imide residue (-C(O)NHC(O)-, etc.), or carbonate group (-OC(O)O-) are preferred, and acid anhydride residue is more preferred.

[0054] When the polymer (1) has a carbonyl group-containing group, the number of carbonyl group-containing groups in the polymer (1) is 1×10 relative to the number of main chain carbons 6 Preferably, it is 500 to 5000, more preferably 600 to 3000, and still more preferably 800 to 1500. The number of carbonyl group-containing groups in the polymer (1) can be quantified according to the composition of the polymer or the method described in International Publication No. 2020 / 145133. In this case, the chemical interaction between the polymer (1) and the inorganic substance is also high, and the inorganic substance is likely to adhere tightly to the surface of the molecular aggregate of the polymer (1) not only physically but also chemically.

[0055] The polymer (1) preferably contains 90 to 99 mol% of TFE units, 0.5 to 9.97 mol% of PAVE units, and 0.01 to 3 mol% of units based on monomers having polar functional groups, respectively, relative to all units.

[0056] As the monomer having a polar functional group, it is preferably itaconic anhydride, citraconic anhydride or 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), and more preferably NAH.

[0057] As a specific example of the polymer (1), the polymer described in International Publication No. 2018 / 16644 can be cited.

[0058] The polymer (2) preferably consists only of TFE units and PAVE units, and contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units relative to all units.

[0059] The content of PAVE units in the polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, relative to all units.

[0060] The degree of freedom of the molecular conformation of this polymer is higher, and the above mechanism of action is easily enhanced.

[0061] In addition, the fact that the polymer (2) does not have a polar functional group means that the number of polar functional groups in the polymer is less than 500 relative to the number of carbon atoms constituting the main chain of the polymer by 1×10 6 Preferably, the number of the above polar functional groups is 100 or less, and more preferably less than 50. The lower limit of the number of the above polar functional groups is usually 0.

[0062] The polymer (2) can be produced using a polymerization initiator or a chain transfer agent that does not generate a polar functional group as the end group of the polymer chain, or can be produced by fluorination treatment of a polymer having a polar functional group (such as a polymer having a polar functional group derived from a polymerization initiator in the end group of the polymer chain).

[0063] As a method of fluorination treatment, a method using fluorine gas can be cited (refer to Japanese Patent Laid-Open No. 2019-194314, etc.).

[0064] These particles may also contain other polymers other than the F polymer. The proportion of the F polymer in the polymers contained in these particles is preferably 80% by mass or more, more preferably 100% by mass.

[0065] As other polymers other than the F polymer, heat-resistant resins such as aromatic polyesters, polyamideimides, thermoplastic polyimides, polyphenylene ethers, and polyphenylene oxides can be cited.

[0066] As the inorganic substances in these particles, oxides, nitrides, elemental metals, alloys, and carbon are preferred, silica (silica), metal oxides (beryllium oxide, cerium oxide, alumina, basic alumina, magnesium oxide, zinc oxide, titanium oxide, etc.), boron nitride, and magnesium metasilicate (talc) are more preferred, inorganic oxides containing at least one element selected from aluminum, magnesium, silicon, titanium, and zinc, talc, and boron nitride are further preferred, silica and boron nitride are particularly preferred, and silica is most preferred. In addition, the inorganic substance may be a ceramic. One kind of inorganic substance can be used, or two or more kinds can be used in combination. In the case of using two or more kinds of inorganic substances in combination, two kinds of silica can be used, or silica and a metal oxide can be used.

[0067] This inorganic substance easily promotes the interaction with the F polymer, and these particles can contain more inorganic substances. In addition, the physical properties based on the inorganic substance are likely to be significantly exhibited in the molded article (for example, the polymer layer and film described later) formed from these particles.

[0068] The inorganic substance in these particles preferably contains silica.

[0069] The content of silica in the inorganic substance is preferably 50% by mass or more, more preferably 75% by mass or more. The upper limit of the silica content is 100% by mass.

[0070] It is preferred that at least a part of the surface of the inorganic substance is surface-treated.

[0071] As the surface treatment agent for this surface treatment, polyhydric alcohols (trimethylolethane, pentaerythritol, propylene glycol, etc.), saturated fatty acids (stearic acid, lauric acid, etc.), their esters, alkanolamines, amines (trimethylamine, triethylamine, etc.), paraffin, silane coupling agents, organosilicons, polysiloxanes, oxides of aluminum, silicon, zirconium, tin, titanium, antimony, etc., their hydroxides, their hydrated oxides, and their phosphates can be cited.

[0072] As the silane coupling agent, 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane or 3-isocyanatopropyltriethoxysilane is preferred.

[0073] The specific surface area (BET method) of the inorganic substance is preferably 1 to 20 m 2 / g, more preferably 5 to 8 m 2 / g. In this case, the interaction between the inorganic substance and the F polymer is easily enhanced. In addition, the inorganic substance and the F polymer are more uniformly distributed in the molded article (such as a polymer layer), and the physical properties of both are more easily balanced.

[0074] Specific examples of the inorganic substance include silica fillers (such as the "admafin (registered trademark)" series manufactured by Admatechs Co., Ltd.), zinc oxide surface-treated with an ester such as dipropylene glycol dicaprate (such as the "FINEX (registered trademark)" series manufactured by Sakai Chemical Industry Co., Ltd.), spherical fused silica (such as the "SFP (registered trademark)" series manufactured by Denka Co., Ltd.), rutile titanium oxide surface-treated with a polyol and an inorganic substance (such as the "TIPAQUE (registered trademark)" series manufactured by Ishihara Sangyo Co., Ltd.), rutile titanium oxide surface-treated with an alkylsilane (such as the "JMT (registered trademark)" series manufactured by Teika Co., Ltd.), hollow silica fillers (such as the "E-SPHERES" series manufactured by Taiheiyo Cement Corporation, the "SiliNax" series manufactured by Nippon Steel Mining Co., Ltd., the "Eccospheres" series manufactured by Emerson and Cuming, the hydrophobic AEROSIL series "RX200" manufactured by Nippon Aerosil Co., Ltd., etc.), talc fillers (such as the "SG" series manufactured by Nippon Talc Co., Ltd.), talc fillers (such as the "BST" series manufactured by Nippon Talc Co., Ltd.), boron nitride fillers (such as the "UHP" series manufactured by Showa Denko K.K., the "Denka Boron Nitride" series (grades "GP", "HGP") manufactured by Denka Co., Ltd., etc.).

[0075] The shape of the inorganic substance is preferably particulate, more preferably spherical, needle-shaped (fibrous) or plate (column)-shaped. Specific shapes of the inorganic substance include spherical, scaly, layered, lamellar, almond-shaped, columnar, cockscomb-shaped, equiaxed, leaf-shaped, mica-shaped, massive, flat-plate-shaped, wedge-shaped, rosette-shaped, reticulate, square-columnar, preferably spherical and scaly. If the inorganic substance of the above shapes is used, the uniformity of the distribution of the inorganic substance in the formed article (such as a polymer layer) is improved, and its function is easily enhanced. The inorganic substance is preferably spherical silica and scaly boron nitride.

[0076] The spherical inorganic substance is preferably approximately spherical. Approximately spherical means that when observing the particles with a scanning electron microscope (SEM), the proportion of spherical particles with a ratio of the minor axis to the major axis of 0.5 or more reaches 95% or more. In this case, the ratio of the minor axis to the major axis of the inorganic substance particles is preferably 0.5 or more, more preferably 0.8 or more, and the above ratio is preferably less than 1. If such highly approximately spherical inorganic substance particles are used, the inorganic substance and the F polymer are more uniformly distributed in the formed article (such as a polymer layer), and the physical properties of both are more easily balanced.

[0077] When the shape of the inorganic substance is scaly, channels are easily formed by the inorganic substance in the formed article, and the thermal conductivity of the formed article is more likely to be improved.

[0078] The aspect ratio of the scaly inorganic substance is preferably 5 or more, more preferably 10 or more. The aspect ratio is preferably 1000 or less.

[0079] The average major axis (average value of the diameters in the long side direction) of the scaly inorganic substance is preferably 1 μm or more, more preferably 3 μm or more. The average major axis is preferably 20 μm or less, more preferably 10 μm or less. The average minor axis (average value of the diameters in the short side direction) is preferably 0.01 μm or more, more preferably 0.1 μm or more. The average minor axis is preferably 1 μm or less, more preferably 0.5 μm or less. In this case, the inorganic substance and the F polymer are more uniformly distributed in the formed article (such as a polymer layer), and the physical properties of both are more easily balanced.

[0080] The scaly inorganic substance can be a single-layer structure or a multi-layer structure.

[0081] As the latter inorganic substance, examples include an inorganic substance having a hydrophobic part on the surface and a hydrophilic part inside. As a specific example, an inorganic substance having a hydrophobic layer, a hydrophilic layer (water-containing layer), and a hydrophobic layer in sequence can be cited. The water content of the hydrophilic layer is preferably 0.3% by mass or more. In this case, not only is the dispersion state of the present particles in the liquid composition easily stabilized, but also the orientation of the inorganic substance in the formed article (such as a polymer layer) is further improved, and it is easy to obtain a formed article (such as a polymer layer) highly having the physical properties of the F polymer and the physical properties of the inorganic substance.

[0082] The D50 of the present particles is preferably 40 μm or less, more preferably 10 μm or less, still more preferably 6 μm or less, and particularly preferably 4 μm or less. The D50 of the present particles is preferably 0.01 μm or more, more preferably 0.1 μm or more, and still more preferably 1 μm or more.

[0083] In addition, the D90 of the present particles is preferably 50 μm or less, more preferably 20 μm or less, and particularly preferably 10 μm or less.

[0084] If the D50 and D90 of the present particles are within the above ranges, the dispersion stability of the present particles in the liquid composition and the physical properties of the molded article (such as a polymer layer) obtained from the liquid composition are more easily improved.

[0085] The powder dynamic friction angle of the present particles is preferably 40 degrees or less, more preferably 30 degrees or less, and still more preferably 20 degrees or less. The powder dynamic friction angle of the present particles is preferably 5 degrees or more. In this case, the present particles are not easily aggregated, and the dispersion stability of the present particles in the liquid composition is easily improved. In addition, the present particles can be more easily dispersed in the liquid composition with a smaller force. When the F polymer in the present particles is polymer (1), this powder dynamic friction angle is easily exhibited.

[0086] The present particles are preferably produced by the following methods: a method of colliding F polymer particles and inorganic particles in a floating state at a temperature above the melting temperature of the F polymer (hereinafter also referred to as "dry method A"), a method of colliding F polymer particles and inorganic particles in a pressed or sheared state (hereinafter also referred to as "dry method B"), and a method of bringing F polymer particles and inorganic particles into contact in a liquid and then solidifying the F polymer particles (hereinafter also referred to as "wet method").

[0087] In dry method A, for example, F polymer particles and inorganic particles are supplied in an atmosphere of high-temperature turbulence, and stress is imparted between them by the collision of the F polymer particles and the inorganic particles to make them composite. This dry method A is sometimes also referred to as a hybrid treatment.

[0088] The atmosphere is formed by a gas. Examples of the gas that can be used include air, oxygen, nitrogen, argon, or a mixture thereof.

[0089] The F polymer particles and the inorganic particles can be supplied all at once in the atmosphere as a pre-mixed mixture, or can be supplied separately in the atmosphere.

[0090] When supplying the F polymer particles and the inorganic particles in a high-temperature atmosphere, it is preferably formed into a state where the particles do not aggregate with each other. As this method, a method of floating the particles in a medium (gas or liquid) can be adopted. A mixture of gas and liquid can also be used as the medium.

[0091] In the dry method A, the F polymer particles and the inorganic particles may be supplied into a high temperature turbulent atmosphere after being prepared, or the F polymer particles and the inorganic particles may be suspended in a medium and then the medium may be heated to form a high temperature turbulent atmosphere.

[0092] As an apparatus that can be used in the former case, there can be cited an apparatus that stirs particles in a cylindrical container by means of a stirring body (e.g., a stirring blade) rotating at high speed, while applying stress to clamp the particles between the inner wall of the container and the stirring body (e.g., the "hybrid mixing system" manufactured by Nara Machinery Manufacturing Co., Ltd.).

[0093] The temperature of the atmosphere is preferably equal to or higher than the melting temperature of the F polymer, more preferably 260 to 400°C, further preferably 320 to 380°C.

[0094] When the inorganic particles contain a large number of aggregates formed by mutual aggregation of primary particles, the aggregates may be broken up before being supplied to the high temperature atmosphere.

[0095] The method for crushing the agglomerates may, for example, be a method using a jet mill, a pin mill or a hammer mill.

[0096] In the dry method B, for example, the F polymer particles and the inorganic particles are pressed onto the inner circumference (receiving surface) of a cylindrical rotating body rotating around the central axis by centrifugal force, and the particles are compounded by applying a pressing force or a shearing force to the particles through the synergistic effect of the inner circumference and the inner stator arranged at a small distance from the inner circumference. This dry method B is sometimes also called mechanical fusion treatment.

[0097] The atmosphere in the cylindrical rotating body may be an inert gas atmosphere or a reducing gas atmosphere. The temperature of the atmosphere is preferably lower than the melting temperature of the F polymer, more preferably lower than 100°C.

[0098] The distance between the inner circumference of the cylindrical rotating body and the inner stator can be appropriately set according to the average particle diameters of the F polymer particles and the inorganic particles. The distance is usually preferably 1 to 10 mm.

[0099] The rotation speed of the cylindrical rotating body is preferably 500 to 10000 rpm. In this case, the production efficiency of the present particles is easily improved.

[0100] When the inorganic particles contain a large number of aggregates formed by mutual aggregation of primary particles thereof, the aggregates may be crushed in the same manner as described in the above-mentioned dry method A before being supplied into the cylindrical rotating body.

[0101] The dry method B can also be carried out using a pulverizing and mixing device having a rotary trough and a pulverizing and mixing blade. The rotary trough has a pulverizing and mixing chamber with an elliptical (abnormal) cross-section whose rotary shaft is arranged horizontally. The pulverizing and mixing blade has an elliptical (abnormal) cross-section that is rotatably inserted into the pulverizing and mixing chamber of the rotary trough, and its rotary shaft is arranged at a concentric position with the rotary shaft of the rotary trough.

[0102] In this pulverizing and mixing device, the F polymer particles and the inorganic particles are pressed between the minor axis part of the pulverizing and mixing chamber and the major axis part of the pulverizing and mixing blade, and a pressing force or a shearing force is applied to the above-mentioned particles to make them composite.

[0103] In addition, in the pulverizing and mixing device, it is preferable that the rotary direction of the rotary trough and the rotary direction of the pulverizing and mixing blade are reverse, and it is preferable to set the rotary speed of the rotary trough slower than the rotary speed of the pulverizing and mixing blade.

[0104] In this pulverizing and mixing device, both the pulverizing and mixing chamber and the pulverizing and mixing blade have abnormal cross-sections. In the pulverizing and mixing chamber, the flowing F polymer particles and inorganic particles that fall due to their own weight can be repeatedly subjected to instantaneous pressing force or shearing force. Thereby, for the above-mentioned particles, pulverizing and mixing can be carried out in a short time while reducing the adverse effects brought by heat, so it is easy to obtain the particles with the target characteristics.

[0105] In the wet method, for example, inorganic particles are added and mixed into the dispersion liquid containing F polymer particles. Specifically, after the inorganic particles are dispersed into a liquid dispersion medium, they are added and mixed into the dispersion liquid containing F polymer particles. This method is beneficial to the mixing between the inorganic particles and the F polymer particles.

[0106] If the mixed liquid containing F polymer particles and inorganic particles is made unstable and solidified, the F polymer particles and the inorganic particles can be composite.

[0107] When the inorganic substance is silica, the inorganic particles are preferably colloidal silica.

[0108] The dispersion liquid containing F polymer particles can be stirred during the process of adding the inorganic particles or after the addition is completed.

[0109] As the device for this stirring, for example, a stirring device having blades (stirring blades) such as propeller blades, turbine blades, paddle blades, and shell-type blades can be cited.

[0110] The stirring speed at this time only needs to be able to efficiently disperse the inorganic particles into the dispersion liquid containing F polymer particles, and it is not necessary to apply a high shearing force to the F polymer particles.

[0111] From the perspective of further improving the adhesion (bonding property) with inorganic particles, it is preferable to perform surface treatment on the F polymer particles before or simultaneously with mixing with the inorganic particles.

[0112] Examples of the surface treatment include plasma treatment, corona discharge treatment, etching treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, and ozone exposure treatment. Plasma treatment (especially low-temperature plasma treatment) is preferred.

[0113] In addition, when the F polymer particles and the inorganic particles collide by the dry method A and the dry method B, heat is easily and uniformly transferred to these particles, and the densification and spheroidization of the present particles are easy to perform, so it is preferred. In this case, the sphericity of the present particles is preferably 0.5 or more.

[0114] Preferred forms of the present particles include a form in which the F polymer is the core and the inorganic substance is attached to the surface of the core (hereinafter also denoted as "form I"), and a form in which the inorganic substance is the core and the F polymer is attached to the surface of the core (hereinafter also denoted as "form II").

[0115] Here, the "core" refers to the core (central part) necessary for forming the particle shape of the present particles, and does not refer to the main component in the composition of the present particles.

[0116] The attachment (inorganic substance or F polymer) attached to the surface of the core may be attached to only a part of the surface of the core, or may be attached to most or the entire surface thereof. In the former case, it can be said that the attachment adheres to the surface of the core in a dust-like state, in other words, it is formed in a state where most parts of the surface of the core are exposed. In the latter case, it can be said that the attachment covers the surface of the core everywhere or the attachment covers the surface of the core, and the present particles can also be said to have a core-shell structure formed by the core and the shell covering the core.

[0117] In the case of form I, both the core of the F polymer and the inorganic substance are preferably in the form of particles. In this case, the inorganic substance having a hardness higher than that of the F polymer is exposed on the surface, improving the fluidity of the present particles and facilitating the improvement of its operability.

[0118] In addition, in the case of form I, the core of the F polymer may be composed of a single particle of the F polymer or an aggregate of particles of the F polymer.

[0119] The present particles of form I are preferably manufactured by the dry method A or the dry method B. In this case, it is preferable to set the D50 of the F polymer particles to be larger than the D50 of the inorganic particles and set the amount of the F polymer particles to be larger than the amount of the inorganic particles. If such a relationship is set and the present particles are manufactured by the dry method A or the dry method B, it is easy to obtain the present particles of form I.

[0120] Based on the D50 of the F polymer particles, the D50 of the inorganic particles is preferably 0.0001 to 0.5, more preferably 0.0001 to 0.1, and further preferably 0.002 to 0.02. As specific preferred forms, there may be cited forms in which the D50 of the F polymer particles exceeds 20 μm and the D50 of the inorganic particles is 10 μm or less, forms in which the D50 of the F polymer particles exceeds 2 μm and the D50 of the inorganic particles is 1 μm or less, and forms in which the D50 of the F polymer particles exceeds 1 μm and the D50 of the inorganic particles is 0.1 μm or less.

[0121] Relative to 100 parts by mass of the F polymer particles, the amount of the inorganic particles is preferably 0.1 part by mass or more, more preferably 1 part by mass or more. The upper limit is preferably 50 parts by mass, more preferably 25 parts by mass, and further preferably 5 parts by mass.

[0122] In the present particles of Form I thus obtained, the D50 of the F polymer core is greater than the D50 of the inorganic particles and the mass of the F polymer in the present particles is greater than the mass of the inorganic matter. In this case, the surface of the F polymer core can be coated with a larger amount of inorganic particles, and the present particles of Form I are formed into a core-shell structure. Further, in this case, aggregation between the F polymer particles is suppressed, and it is easy to obtain composite particles (the present particles) in which inorganic particles are attached to the core formed by individual F polymer particles.

[0123] In Form I, the inorganic particles are preferably spherical or scaly, more preferably spherical, and further preferably approximately spherical. In this case, the ratio of the minor axis to the major axis of the inorganic particles is preferably 0.6 or more, more preferably 0.8 or more. The above ratio is preferably less than 1. Here, "spherical" includes not only spherical but also slightly deformed spherical.

[0124] If such highly approximately spherical inorganic particles are used, the inorganic matter and the F polymer are more uniformly distributed in the molded article (such as a polymer layer), and it is easier to balance the physical properties of both.

[0125] In Form I, the D50 of the inorganic particles is preferably in the range of 0.001 to 10 μm, more preferably in the range of 0.001 to 0.3 μm, further preferably 0.005 to 0.2 μm, and particularly preferably 0.01 to 0.1 μm. If the D50 is within the above range, the handleability and fluidity of the present particles are easily improved, and the dispersion stability is also easily improved.

[0126] Further, the particle size distribution of the inorganic particles is preferably 3 or less, more preferably 2.9 or less, with the value of D90 / D10 as an index. Here, "D10" is measured in the same manner as D50 and D90, and is the volume-based cumulative 10% diameter of the object. A narrow particle size distribution is preferred from the viewpoint of easily controlling the fluidity of the obtained present particles.

[0127] In Form I, it is preferable to perform surface treatment on at least a part of the surface of the inorganic particles, and more preferably, surface treatment is carried out with a silazane compound such as hexamethyldisilazane or a silane coupling agent. As the silane coupling agent, the above-mentioned compounds can be exemplified.

[0128] In Form I, one type of inorganic particles can be used, or two or more types can be used in combination. When two types of inorganic particles are used in combination, the average particle diameters of the respective inorganic particles can be different from each other, and the mass ratio of the contents of the respective inorganic particles can be appropriately set according to the required functions.

[0129] In addition, in Form I, it is preferable that a part of the inorganic particles is embedded in the core of the F polymer. Thereby, the adhesion of the inorganic particles to the core of the F polymer is higher, and the inorganic particles are less likely to fall off from the present particles. That is, the stability of the present particles is further improved.

[0130] In the present particles of Form I, the D50 of the F polymer core is preferably 0.1 μm or more, more preferably more than 1 μm. The upper limit is preferably 100 μm, more preferably 50 μm, and further preferably 10 μm.

[0131] In addition, the D50 of the inorganic particles is preferably 0.001 μm or more, more preferably 0.01 μm or more. The upper limit is preferably 10 μm, more preferably 1 μm, and further preferably 0.1 μm.

[0132] In the present particles of Form I, the proportion of the F polymer is preferably 50 to 99% by mass, more preferably 75 to 99% by mass. The proportion of the inorganic matter is preferably 1 to 50% by mass, more preferably 1 to 25% by mass.

[0133] In addition, the ratio of the fluorine element content to the inorganic element content on the surface of the present particles of Form I measured by energy dispersive X-ray spectroscopy is preferably less than 1, more preferably 0.5 or less, and further preferably 0.1 or less. The above ratio is preferably 0 or more. The target elements in this measurement are four elements: carbon element, fluorine element, oxygen element, and silicon element, and sometimes the respective proportions (unit: atomic %) of the fluorine element and the silicon element in their total are used as the contents of the respective elements.

[0134] In other words, the present particles of Form I with the above mass ratio are particles highly coated with inorganic matter on the surface, and not only have excellent particle properties of the inorganic matter (such as dispersibility in liquid), but also the formed molded article is likely to highly possess the physical properties of the inorganic matter and the F polymer.

[0135] The present particles in Form I can be further surface-treated according to the physical properties of the inorganic substances attached to the surface. As a specific example of such surface treatment, a method of surface-treating the present particles in Form I containing silica as the inorganic substance with siloxanes (such as polydimethylsiloxane) or silane coupling agents can be cited.

[0136] This surface treatment can be carried out by mixing the dispersion liquid in which the present particles are dispersed with siloxanes or silane coupling agents, reacting the siloxanes or silane coupling agents, and then recovering the particles.

[0137] As the silane coupling agent, the above compounds are preferred.

[0138] By this method, not only the amount of silica on the surface of the above present particles can be adjusted, but also the surface physical properties can be further regulated.

[0139] In the case of Form II, it is preferred that at least a part of the F polymer is welded to the surface of the core of the inorganic substance. Thereby, the adhesion of the F polymer to the core of the inorganic substance is further improved, and the F polymer particles are less likely to fall off from the present particles. That is, the stability of the present particles is further improved.

[0140] The core of the inorganic substance is preferably in the form of particles. In this case, the surface of the inorganic substance core in the present particles is easily coated with the F polymer, and thus, it is easy to prevent the present particles from aggregating.

[0141] The particles in Form II are also preferably manufactured by dry method A or dry method B. In this case, it is preferred that the D50 of the inorganic substance particles is set to be larger than the D50 of the F polymer particles, and the amount of the inorganic substance particles is set to be larger than the amount of the F polymer particles. If the relationship is set as such and the present particles are manufactured by dry method A or dry method B, it is easy to obtain the present particles in Form II.

[0142] Based on the D50 of the inorganic substance particles, the D50 of the F polymer particles is preferably 0.0001 to 0.02, more preferably 0.002 to 0.1.

[0143] In addition, with respect to 100 parts by mass of the inorganic substance particles, the amount of the F polymer particles is preferably 0.1 part by mass or more, more preferably 1 part by mass or more. The upper limit is preferably 50 parts by mass, more preferably 10 parts by mass, and further preferably 3 parts by mass.

[0144] In the present particles in Form II obtained thereby, the D50 of the inorganic substance core is larger than the D50 of the F polymer particles and the mass of the inorganic substance in the present particles is larger than the mass of the F polymer. In this case, the surface of the inorganic substance core is coated with a larger amount of F polymer particles, and the present particles in Form II are formed into a core-shell structure.

[0145] In the particles of Form II, the D50 of the inorganic nucleus is preferably 0.1 μm or more, more preferably more than 1 μm. The upper limit is preferably 30 μm, more preferably 6 μm.

[0146] In addition, the proportion of the inorganic substance in the particles of Form II is preferably 50 to 99% by mass, more preferably 60 to 90% by mass. The proportion of the F polymer is preferably 1 to 50% by mass, more preferably 10 to 40% by mass.

[0147] The liquid composition of the present invention (hereinafter also referred to as "the present composition") is a composition in which the present particles and a liquid dispersion medium are included and the present particles are dispersed in the liquid dispersion medium.

[0148] The present particles can exhibit a sufficiently high polarity and can be stably dispersed even when added in a large amount to the liquid dispersion medium. In addition, in a molded article (polymer layer, film, etc.) formed from the liquid composition, the F polymer and the inorganic substance are more uniformly distributed, and it is easy to highly exhibit the physical properties (electrical properties, adhesiveness, etc.) based on the F polymer and the physical properties (low linear expansion property, etc.) based on the inorganic substance.

[0149] The liquid dispersion medium of the present invention is a liquid compound that functions as a dispersion medium for the present particles and is inert at 25°C. The liquid dispersion medium can be water or a non-aqueous dispersion medium. The liquid dispersion medium can be one kind or two or more kinds. In this case, it is preferable that different kinds of liquid compounds are compatible.

[0150] The boiling point of the liquid dispersion medium is preferably 125 to 250°C. When within this range, when the liquid dispersion medium is removed from the liquid composition, the present particles are highly fluid and densely packed, and as a result, it is easy to form a dense molded article (polymer layer, etc.).

[0151] As the liquid dispersion medium, from the viewpoint of improving the dispersion stability of the present particles in the present composition, at least one liquid compound selected from water, amides, ketones, and esters is preferably used, and water, N-methyl-2-pyrrolidone, γ-butyrolactone, methyl ethyl ketone, cyclohexanone, and cyclopentanone are more preferably used.

[0152] When the liquid dispersion medium contains an aprotic polar solvent such as N-methyl-2-pyrrolidone, at least a part of the surface of the inorganic substance in the present particles is preferably surface-treated with a silane coupling agent having at least one group selected from an amino group, a vinyl group, and a (meth)acryloyloxy group, and more preferably surface-treated with phenylaminosilane.

[0153] When the liquid dispersion medium contains a nonpolar solvent such as toluene, at least a part of the surface of the inorganic substance in the present particles is preferably hydrophobized and preferably surface-treated with a silane coupling agent having at least one group selected from an alkyl group and a phenyl group.

[0154] In addition, when the liquid dispersion medium contains a protic polar solvent such as water, the inorganic substance in the present particles is preferably not surface-treated.

[0155] When the above liquid dispersion medium and inorganic substance are combined, the dispersion stability of the present composition is more likely to be improved.

[0156] The content of the present particles in the present composition is preferably 1 to 50% by mass, more preferably 10 to 40% by mass.

[0157] The content of the liquid dispersion medium in the present composition is preferably 50 to 99% by mass, more preferably 60 to 90% by mass.

[0158] From the perspective of further improving the dispersion stability of the present particles, suppressing particle sedimentation, and improving operability, the present composition preferably further contains a surfactant. The surfactant is preferably a nonionic surfactant.

[0159] The hydrophilic part of the surfactant preferably has an oxyalkylene group or an alcohol hydroxyl group.

[0160] The hydrophobic part of the surfactant preferably has an alkyl group, an ethynyl group, a polysiloxanyl group, a perfluoroalkyl group, or a perfluorovinyl group. The surfactant is preferably a polyoxyalkylene alkyl ether, an acetylene-type surfactant, a silicone surfactant, or a fluorine surfactant, more preferably a silicone surfactant. The silicone surfactant can be used in combination with a polyoxyalkylene alkyl ether.

[0161] As specific examples of the surfactant, the "Ftergent" series (manufactured by Neos Co., Ltd.), the "Surflon" series (manufactured by AGC Seimi Chemical Co., Ltd.), the "MEGA FACE" series (manufactured by DIC Corporation), the "Unidyne" series (manufactured by Daikin Industries, Ltd.), "BYK-347", "BYK-349", "BYK-378", "BYK-3450", "BYK-3451", "BYK-3455", "BYK-3456" (manufactured by BYK-Chemie Japan Co., Ltd.), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be cited.

[0162] When the present composition contains a surfactant, its content is preferably 1 to 15% by mass. In this case, the dispersion stability of the present particles in the present composition is more likely to be improved.

[0163] The viscosity of the present composition is preferably 50 mPa·s or more, more preferably 100 mPa·s or more. The viscosity of the present composition is preferably 1000 mPa·s or less, more preferably 800 mPa·s or less. In this case, the coating property of the present composition is excellent, and thus it is easy to form a shaped article (such as a polymer layer) having an arbitrary thickness.

[0164] The thixotropic ratio of the present composition is preferably 1.0 or more. The thixotropic ratio of the present composition is preferably 3.0 or less, more preferably 2.0 or less. In this case, the present composition not only has excellent coating property but also excellent homogeneity, and thus it is easy to form a denser shaped article (such as a polymer layer).

[0165] The present composition may further contain a polymer other than the F polymer or its precursor. Examples of the polymer or its precursor include polytetrafluoroethylene (PTFE), a polymer containing TFE units and PAVE units (PFA), a polymer containing TFE units and units based on hexafluoropropylene (FEP), a polymer containing TFE units and units based on ethylene (ETFE), polyvinylidene fluoride (PVDF), polyimide, polyarylate, polysulfone, polyarylsulfone, polyamide, polyetheramide, polyphenylene ether, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystalline polyester, liquid crystalline polyesteramide, epoxy resin, maleimide resin, etc. PFA may be an F polymer or a PFA other than the F polymer.

[0166] These polymers or their precursors may be dispersed in the present composition or dissolved in the present composition.

[0167] In addition, these polymers or their precursors may be thermoplastic or thermosetting.

[0168] In addition to the above components, the present composition may further contain other components such as a thixotropy imparting agent, a viscosity modifier, an antifoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightening agent, a coloring agent, a conductive agent, a mold release agent, a surface treatment agent, a flame retardant, and various fillers.

[0169] In the method for manufacturing the laminate of the present invention (hereinafter also referred to as "Method 1"), the present composition is applied to the surface of the substrate layer and heated to form a polymer layer, thereby obtaining a laminate having a substrate layer and a polymer layer. More specifically, in Method 1, the present composition is applied to the surface of the substrate layer to form a liquid film, the liquid film is heated to remove the liquid dispersion medium to form a dry film, and then the dry film is heated to bake the F polymer, thereby obtaining a laminate having a polymer layer containing an F polymer and an inorganic substance on the surface of the substrate layer.

[0170] The heating temperature of the liquid film is preferably 120°C to 200°C. The heating temperature of the dried film is preferably 250°C to 400°C, more preferably 300 to 380°C.

[0171] As the respective heating methods, methods using an oven, methods using a ventilation drying furnace, methods of irradiating thermal rays such as infrared rays, etc. can be cited.

[0172] As the base material layer, a metal base material layer (metal foils such as copper, nickel, aluminum, titanium, their alloys, etc.), a resin film (films such as PTFE, polyimide, polyarylate, polysulfone, polyarylsulfone, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystalline polyester, liquid crystalline polyester amide, etc.), a prepreg (precursor of a fiber-reinforced resin substrate) can be cited.

[0173] The application of this composition is preferably carried out by coating. As the coating methods, spray method, roll coating method, spin coating method, gravure coating method, microgravure coating method, gravure offset coating method, knife coating method, brush coating method, bar coating method, die coating method, jet Meyer rod coating method, comma coating method can be cited.

[0174] The thickness of the polymer layer is preferably 0.1 to 150 μm. Specifically, when the base material layer is a metal foil, the thickness of the polymer layer is preferably 1 to 30 μm. When the base material layer is a resin film, the thickness of the polymer layer is preferably 1 to 150 μm, more preferably 10 to 50 μm.

[0175] This composition can be applied to only one surface of the base material layer or can be applied to both surfaces of the base material layer. In the former case, a laminate having the base material layer and a polymer layer on one surface of the base material layer can be obtained. In the latter case, a laminate having polymer layers on both surfaces of the base material layer can be obtained. The latter laminate is less likely to warp, so its workability during processing is excellent.

[0176] As specific examples of the laminate, a metal-clad laminate having a metal foil and a polymer layer on at least one surface of the metal foil, a multilayer film having a polyimide film and polymer layers on both surfaces of the polyimide film can be cited.

[0177] As the metal foil, a carrier metal foil containing two or more layers of metal foil can also be used. As the carrier metal foil, a carrier copper foil (thickness: 10 to 35 μm) and an ultra-thin copper foil (thickness: 2 to 5 μm) laminated on the carrier copper foil via a release layer can be cited. If this carrier copper foil is used, a fine pattern can be formed by the MSAP (modified semi-additive) method. As the above release layer, a metal layer containing nickel or chromium or a multilayer metal layer in which this metal layer is laminated is preferred.

[0178] As a specific example of the metal foil with a carrier, the trade name "FUTF-5DAF-2" manufactured by Fukuda Metal Foil Powder Industry Co., Ltd. (Fukuda Metal Foil Powder Industry Co., Ltd.) can be mentioned.

[0179] In order to further improve the adhesiveness of the outermost surface (the surface of the polymer layer on the opposite side to the substrate layer) of the laminate in Method 1, the outermost surface may be further surface treated.

[0180] The surface treatment method may, for example, be annealing treatment, corona treatment, plasma treatment, ozone treatment, excimer treatment or silane coupling treatment.

[0181] The conditions for the annealing treatment are preferably a temperature of 120 to 180° C., a pressure of 0.005 to 0.015 MPa, and a time of 30 to 120 minutes.

[0182] Examples of the gas used in the plasma treatment include oxygen, nitrogen, a rare gas (argon, etc.), hydrogen, ammonia, and vinyl acetate. These gases may be used alone or in combination of two or more.

[0183] Another substrate may be stacked on the outermost surface of the stacked body in Method 1.

[0184] As other substrates, there may be mentioned a heat-resistant resin film, a prepreg which is a precursor of a fiber-reinforced resin sheet, a laminate having a heat-resistant resin film layer, or a laminate having a prepreg layer.

[0185] Prepreg is a sheet-like substrate made by impregnating a base material (such as short hemp and woven fabric) of reinforcing fibers (such as glass fibers and carbon fibers) with a thermosetting resin or a thermoplastic resin.

[0186] The heat-resistant resin film is a film containing one or more heat-resistant resins. Examples of the heat-resistant resin include polyimide, polyarylate, polysulfone, polyarylsulfone, aromatic polyamide, aromatic polyether amide, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystalline polyester, and liquid crystalline polyester amide. Polyimide (particularly aromatic polyimide) is preferred.

[0187] As a lamination method, a method of heat-pressing the laminate and another substrate may be mentioned.

[0188] When the other substrate is a prepreg, the hot pressing conditions are preferably a temperature of 120 to 400° C., a vacuum atmosphere of 20 kPa or less, and a pressurizing pressure of 0.2 to 10 MPa.

[0189] The laminate in the present method 1 has a polymer layer with excellent electrical properties, and thus is suitable as a printed circuit board material. Specifically, the laminate of the present invention can be used as a flexible metal-clad laminate or a rigid metal-clad laminate for the manufacture of printed circuit boards, and is particularly suitable as a flexible metal-clad laminate for the manufacture of flexible printed circuit boards.

[0190] A printed circuit board can be obtained by etching the metal foil of a laminate (metal foil with a polymer layer) whose base material layer is a metal foil to form a transmission circuit. Specifically, a printed circuit board can be manufactured by a method of processing the metal foil into a specified transmission circuit by etching the metal foil, or by a method of processing the metal foil into a specified transmission circuit by using an electroplating method (semi-additive process (SAP process), MSAP process, etc.).

[0191] The printed circuit board made of a metal foil with a polymer layer sequentially has a transmission circuit formed by the metal foil and a polymer layer. As a specific example of the structure of the printed circuit board, examples include: transmission circuit / polymer layer / prepreg layer, transmission circuit / polymer layer / prepreg layer / polymer layer / transmission circuit.

[0192] In the manufacture of this printed circuit board, an interlayer insulating film can be formed on the transmission circuit, a solder resist can be laminated on the transmission circuit, or a cover layer film can be laminated on the transmission circuit. These interlayer insulating films, solder resists, and cover layer films can also be formed from this composition.

[0193] In the manufacturing method of the film of the present invention (hereinafter also referred to as "this method 2"), the present particles and a fluoroolefin polymer are melt-kneaded and then extrusion-molded to obtain a film.

[0194] Since the present particles contain an F polymer with a high interaction (compatibility) with the fluoroolefin polymer, in the film obtained by uniformly melt-kneading the two, the F polymer, the fluoroolefin polymer, and the inorganic substance are uniformly distributed, and it is easy to highly exhibit the physical properties (especially electrical properties) based on the F polymer and the fluoroolefin polymer and the physical properties (such as low linear expansion) based on the inorganic substance.

[0195] The fluoroolefin polymer melt-kneaded with the present particles can be an F polymer or a polymer containing units based on fluoroolefins other than the F polymer.

[0196] Examples of the fluoroolefin polymer include PTFE, PFA, FEP, ETFE, PVDF. PFA can be an F polymer or PFA other than the F polymer.

[0197] The melting temperature (melting point) of the fluoroolefin polymer is preferably 160 to 330 °C.

[0198] The glass transition temperature of the fluoroolefin polymer is preferably 45 to 150 °C.

[0199] The fluoroolefin polymer preferably has a polar functional group. Preferably, both the F polymer and the fluoroolefin polymer have polar functional groups. The types of polar functional groups and the methods of introducing them, including the preferred types and methods, are the same as those described for the above-mentioned F polymer.

[0200] The melt-kneading of these particles and the TFE polymer is carried out, for example, using a single-screw kneader. The single-screw kneader has a cylinder and one screw rotatably provided in the cylinder. If a single-screw kneader is used, it is easy to prevent the deterioration of the F polymer and the TFE polymer during melt-kneading.

[0201] In this case, when the total length of the screw is L (mm) and the diameter is D (mm), the effective length (L / D) expressed as the ratio of the total length L to the diameter D is preferably 30 to 45. If the effective length is within the above range, sufficient shear stress can be applied to the F polymer and the TFE polymer while preventing their deterioration, and it is easy to reduce the temperature non-uniformity of the melt-kneaded product.

[0202] The rotation speed of the screw is preferably 10 to 50 ppm.

[0203] The melt-kneaded product can be extruded from a T-die provided at the front end of the cylinder. Then, the melt-kneaded product extruded from the T-die contacts multiple cooling rolls and solidifies into a film. The obtained strip-shaped film is wound onto a winding roll.

[0204] The thickness of the film is preferably 5 to 150 μm, more preferably 10 to 100 μm.

[0205] The shape of the film can be strip-shaped or leaf-shaped. The length in the long side direction of the strip-shaped film is preferably 100 m or more. The upper limit of the length in the long side direction is usually 2000 m. The length in the short side direction of the strip-shaped film is preferably 1000 mm or more, and the upper limit of the length in the short side direction is usually 3000 mm.

[0206] The obtained film is overlapped with a substrate layer and then hot-pressed to obtain a laminate having a polymer layer formed by the film and a substrate layer.

[0207] The hot-pressing conditions are preferably as follows: the temperature is 120 to 300 °C, the atmospheric pressure is a vacuum of 20 kPa or less, and the pressing pressure is 0.2 to 10 MPa.

[0208] In addition, the form of the substrate layer, the printed circuit board using the laminate, and the multilayer printed circuit board, including their preferred forms, are the same as those described in the above-mentioned Method 1.

[0209] In addition, a blown film can also be manufactured by replacing the T-die with a circular die.

[0210] As described above, the composite particles, the method for producing the composite particles, the liquid composition, the method for producing the laminate, and the method for producing the film of the present invention have been described, but the present invention is not limited to the configurations of the above-described embodiments.

[0211] For example, with respect to the composite particles and the liquid composition of the present invention, any other arbitrary configurations may be added to the configurations of the above-described embodiments, or they may be replaced with any configurations that exhibit the same functions.

[0212] In addition, with respect to the method for producing the composite particles, the method for producing the laminate, and the method for producing the film of the present invention, any other arbitrary steps may be added to the configurations of the above-described embodiments, or they may be replaced with any steps that produce the same effects.

[0213] Examples

[0214] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

[0215] 1. Preparation of Each Component

[0216] [Particles of Polymer]

[0217] Particles 1 of F-polymer 1: Particles (D50: 2.0 μm) composed of F-polymer 1 having a polar functional group containing 97.9 mol% of TFE units, 0.1 mol% of NAH units, and 2.0 mol% of PPVE units (melting temperature: 300 °C)

[0218] Particles of F-polymer 2: Particles (D50: 2.6 μm) composed of F-polymer 2 having no polar functional group containing 97.5 mol% of TFE units and 2.5 mol% of PPVE units (melting temperature: 300 °C)

[0219] Particles of non-F-polymer: Particles (D50: 2.1 μm) composed of non-F-polymer having no polar functional group containing 98.7 mol% of TFE units and 1.3 mol% of PPVE units (melting temperature: 305 °C)

[0220] PTFE particles: Particles (D50: 2.4 μm) composed of fibrillar non-thermally fusible PTFE

[0221] Particles 2 of F-polymer 1: Particles (D50: 25 μm) composed of F-polymer 1

[0222] In addition, the number of carbonyl groups per 1 × 10 6 main-chain carbon atoms in F-polymer 1 is 1000, and in F-polymer 2 is 40. The melt viscosities of F-polymer 1 and F-polymer 2 at 380 °C are both in the range of 1 × 10 3 to 1 × 10 6In the range of Pa·s, the glass transition temperatures of both F-polymer 1 and F-polymer 2 are in the range of 80 to 100 °C.

[0223] [Particles of inorganic substances]

[0224] Silica particles 1: Spherical particles composed of silica (D50: 0.5 μm, approximately spherical)

[0225] Silica particles 2: Spherical particles composed of silica surface-treated with a silane coupling agent (D50: 0.03 μm, approximately spherical)

[0226] Boron nitride particles: Flaky particles composed of boron nitride (D50: 7.0 μm, aspect ratio: 1000 or less)

[0227] 2. Manufacture of composite particles

[0228] (Example 1)

[0229] Prepare a mixture of 98 parts by mass of particles of F-polymer 1 and 2 parts by mass of silica particles 1.

[0230] Then, the mixture is introduced into a powder processing apparatus (mechanical fusion) having a cylindrical rotating body with a bearing surface on its inner peripheral surface and an inner stator disposed at a small distance from the bearing surface. Then, the cylindrical rotating body is rotated at high speed around the central axis. By using the centrifugal force generated at this time, the particles are pressed onto the bearing surface, and the mixture is introduced into the narrow space (pressing space) between the bearing surface and the inner stator, and the particles are made to collide in a shear state for processing. The atmosphere temperature of the cylindrical rotating body during processing is maintained below 100 °C, and the processing time is 15 minutes.

[0231] The obtained processed product is a fine powder. After analyzing this powder with an optical microscope, it was confirmed to be composite particle 1 having a core-shell structure in which F-polymer 1 is the core and silica particles 1 are attached to the surface of the core.

[0232] The ratio of the fluorine element content to the silicon element content on the surface of the composite particles (hereinafter also referred to as "F / Si ratio") measured by energy dispersive X-ray spectroscopy is 0.006. The target elements in this measurement are four elements, namely carbon element, fluorine element, oxygen element, and silicon element, and the content of each element is the proportion of fluorine element and silicon element in their total (unit: atomic %).

[0233] The shape of composite particle 1 is spherical, its D50 is 20 μm, and the powder dynamic friction angle is 18 degrees.

[0234] After producing the composite particles 1, without cleaning the mechanical fusion device, a mixture of 98 parts by mass of the particles 1 of F polymer 1 and 2 parts by mass of the silica particles 1 was directly introduced into the mechanical fusion device to obtain a treated product, which was the same particles as the above composite particles 1.

[0235] (Example 2)

[0236] Except that a mixture was prepared using 95 parts by mass of the particles 1 of F polymer 1 and 5 parts by mass of the silica particles 1, composite particles 2 were obtained in the same operation as in Example 1. The F / Si ratio of the composite particles 2 was 0.337, and its D50 was 30 μm.

[0237] (Example 3)

[0238] Except that a mixture was prepared using 75 parts by mass of the particles 1 of F polymer 1 and 25 parts by mass of the silica particles 1, composite particles 3 were obtained in the same operation as in Example 1. The F / Si ratio of the composite particles 3 was 0.672, and its D50 was 40 μm.

[0239] (Example 4)

[0240] Except that the particles 1 of F polymer 1 were changed to the particles of F polymer 2, composite particles 4 were obtained in the same operation as in Example 2. The F / Si ratio of the composite particles 4 was 0.555, its D50 was 35 μm, and the powder dynamic friction angle was 25 degrees.

[0241] (Example 5)

[0242] Except that the particles 1 of F polymer 1 were changed to the particles of non-F polymer, composite particles 5 were obtained in the same operation as in Example 1. The F / Si ratio of the composite particles 5 exceeded 1, its D50 was 50 μm, and the powder dynamic friction angle was 45 degrees.

[0243] (Example 6)

[0244] Except that the particles 1 of F polymer 1 were changed to the particles of PTFE, the treatment was carried out in the same manner as in Example 1. The obtained treated product was a non-particle-like lump.

[0245] (Example 7)

[0246] Except that a mixture was prepared using 10 parts by mass of the particles 1 of F polymer 1 and 90 parts by mass of the silica particles 1, composite particles 7 were obtained in the same operation as in Example 1. The composite particles 7 were analyzed with an optical microscope, and it was confirmed that they were composite particles with a core-shell structure in which silica was the core and F polymer 1 was attached to the surface of the core to form a shell.

[0247] (Example 8)

[0248] Except for changing the silica particles 1 to silica particles 2, composite particles 8 were obtained by the same operation as in Example 1. The F / Si ratio of the composite particles 8 was 0.005, its D50 was 5.5 μm, and the powder dynamic friction angle was 16 degrees.

[0249] (Example 9)

[0250] First, a mixture of 70 parts by mass of particles 2 of F polymer 1 and 30 parts by mass of boron nitride particles was prepared.

[0251] Then, the mixture was put into a powder processing device (hybrid system) in a cylindrical container where the particles were stirred by a stirring blade rotating at high speed, and stress was applied to clamp the particles between the inner wall of the container and the stirrer. Subsequently, the particles 2 of F polymer 1 and the boron nitride particles were made to float and collide in a high-temperature turbulent atmosphere, and stress was applied between them for compounding treatment. During the treatment, the temperature inside the device was maintained below 100 °C in a nitrogen atmosphere, and the treatment time was 15 minutes.

[0252] The obtained treated product was a fine powder. After analyzing the powder with an optical microscope, it was confirmed to be composite particles 9 with a core-shell structure in which F polymer 1 was the core and boron nitride particles were attached to the surface of the core to form a shell.

[0253] The shape of the composite particles 9 was spherical, its D50 was 35 μm, and the powder dynamic friction angle was 26 degrees.

[0254] 3. Evaluation

[0255] 3-1. Evaluation of dispersion stability

[0256] Dispersion liquids were prepared by dispersing each of the composite particles 1 to 5, 7 to 9 in water, and after allowing them to stand for a specified time, their dispersion stabilities were evaluated according to the following criteria.

[0257] [Evaluation criteria]

[0258] 〇: Foaming during preparation was suppressed, and no sediment was produced after standing at 25 °C for 3 days after preparation.

[0259] △: Foaming occurred during preparation, but no sediment was produced after standing at 25 °C for 3 days after preparation.

[0260] ×: Sediment was produced after standing at 25 °C for 3 days.

[0261] As a result, the composite particles 1, 2, 7 to 9 were "〇", the composite particles 3 and 4 were "△", and the composite particles 5 were "×". The composite particles 8 took the longest time to produce sediment.

[0262] 3-2. Evaluation of powder shedding and warping

[0263] First, the composite particles 1 to 4, 7 to 9 and N-methyl-2-pyrrolidone (NMP) were put into a pot. After zirconia balls were put into the pot, the pot was rolled under the condition of 150 rpm for 1 hour to prepare a liquid composition.

[0264] Then, the liquid composition was coated on the surface of a long strip of copper foil using a bar coater to form a liquid film. Next, the metal foil with the liquid film formed thereon was passed through a drying furnace at 120 °C for 5 minutes and dried by heating to obtain a dried film. Then, the dried film was heated in a nitrogen furnace at 380 °C for 3 minutes. Thereby, a laminate having a copper foil and a polymer layer including a polymerized fired product and an inorganic substance on its surface was obtained.

[0265] Next, the powder shedding of the dried film and the warpage of the laminate were evaluated.

[0266] The edge part of the dried film was visually confirmed, and the powder shedding of the dried film was evaluated according to the following criteria.

[0267] [Evaluation criteria for powder shedding]

[0268] 〇: No shedding was confirmed at the edge part of the dried film.

[0269] △: A part of the edge part of the dried film was confirmed to have shed.

[0270] ×: A large range of the edge part of the dried film was confirmed to have shed.

[0271] In addition, a square test piece with a side length of 180 mm was cut out from the laminate, and the test piece was measured according to the measurement method specified in JIS C 6471:1995, and the warpage of the laminate was evaluated according to the following criteria.

[0272] [Evaluation criteria for warpage]

[0273] 〇: The coefficient of linear expansion is less than ±20 ppm / °C.

[0274] ×: The coefficient of linear expansion is ±20 ppm / °C or more.

[0275] These results are shown in Table 1 below.

[0276] [Table 1]

[0277] Powder dropping Warpage Composite particle 1 ○ ○ Composite particle 2 △ ○ Composite particle 3 △ × Composite particle 4 × × Composite particle 7 ○ ○ Composite particle 8 ○ ○ Composite particle 9 ○ ○

[0278] 4. Fabrication of the film

[0279] (Example 10)

[0280] Mix the composite particles 1 (50 parts by mass) and the particles 1 of F polymer 1 with a blender to prepare a mixture. Using a single-screw extruder (a single-screw extruder with a 700-mm wide coat hanger die), single-screw extruder), the mixture was extrusion molded at a die temperature of 340 °C to obtain Film 1 with a width of 500 mm, a length of 100 m, and a thickness of 25 μm. The linear expansion coefficient of Film 1 decreased compared to a film formed only of F polymer 1.

[0281] Industrial Applicability

[0282] The composite particles of the present invention have excellent dispersion stability in a liquid composition. The liquid composition can be used to manufacture molded articles (laminates, films, etc.) highly having the physical properties based on F polymer and the characteristics based on inorganic substances. The molded articles of the present invention can be used as antenna components, printed circuit boards, aircraft components, automotive components, sports equipment, food industry products, coatings, cosmetics, etc. Specifically, they can be used as heat dissipation components (heat dissipation components for electronic devices or engines, etc.), wire coating materials (aircraft wires, etc.), electrical insulating tapes, insulating tapes for oil exploration, materials for printed circuit boards, separation membranes (precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode adhesives (for lithium secondary batteries, fuel cells, etc.), copying rollers, furniture, covers for automotive instrument panels, home appliances, etc., sliding members (load bearings, sliding shafts, valves, bearings, gears, cams, conveyor belts, food conveyor belts, etc.), tools (shovels, files, awls, saws, etc.), boilers, hoppers, pipes, ovens, barbecue molds, chutes, plastic molds, toilets, container coating materials, outer surface coating materials for heat exchangers (heat sinks, heat pipes, etc.) of heating and cooling machines, etc.

Claims

1. Composite particles, wherein, Containing a tetrafluoroethylene-based polymer and an inorganic substance with a melting temperature of 260 to 320 °C, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer with polar functional groups containing units based on perfluoro(alkyl vinyl ether), and the inorganic substance is silica or boron nitride. Using the tetrafluoroethylene-based polymer as the core, the inorganic substance is present on the surface of the core. The ratio of the fluorine element content to the inorganic element content on the surface of the composite particles measured by energy-dispersive X-ray spectroscopy is 0.5 or less. Alternatively, using the inorganic substance as the core, the tetrafluoroethylene-based polymer is present on the surface of the core.

2. The composite particles according to claim 1, wherein, The powder dynamic friction angle of the composite particles is 40 degrees or less.

3. The composite particles according to claim 1, wherein, The composite particles are spherical or flaky.

4. The composite particles according to claim 1, wherein, The core of the tetrafluoroethylene-based polymer and the inorganic substance are each in particle form, and the average particle diameter of the core is larger than the average particle diameter of the inorganic substance.

5. The composite particles according to claim 1, wherein, The mass of the inorganic substance in the composite particles is greater than the mass of the tetrafluoroethylene-based polymer.

6. A method for producing composite particles, which is a method for producing the composite particles according to any one of claims 1 to 5, wherein, The composite particles are obtained by colliding the particles of the tetrafluoroethylene-based polymer and the particles of the inorganic substance at a temperature above the melting temperature of the tetrafluoroethylene-based polymer and in a floating state.

7. A method for producing composite particles, which is a method for producing the composite particles according to any one of claims 1 to 5, wherein, The composite particles are obtained by colliding the particles of the tetrafluoroethylene-based polymer and the particles of the inorganic substance in a pressed or sheared state.

8. Liquid composition, wherein, Containing the composite particles according to any one of claims 1 to 5 and a liquid dispersion medium, wherein the composite particles are dispersed in the liquid dispersion medium.

9. The liquid composition according to claim 8, wherein, The liquid dispersion medium is at least one liquid compound selected from water, amides, ketones, and esters.

10. Method for manufacturing a laminate, wherein, Applying the liquid composition according to claim 8 or 9 to the surface of a substrate layer, and forming a polymer layer by heating to obtain a laminate having the substrate layer and the polymer layer.

11. Method for manufacturing a membrane, wherein, The composite particles according to any one of claims 1 to 5 and a fluorinated olefin polymer are melt-kneaded and then extrusion-molded to obtain a film.