JP2022061774A - Manufacturing method of dispersion liquid and manufacturing method of laminated body - Google Patents

Abstract

To provide a manufacturing method capable of industrially and efficiently obtaining dispersion liquid in which when composite particles containing a tetrafluoroethylene polymer and an inorganic material are mixed with a dispersion medium and the composite particles are dispersed in a dispersion medium, deformation and modification of composite particles are suppressed and a manufacturing method of a laminated body excellent in appearance of surface smoothness using the dispersion liquid obtained according to the manufacturing method.SOLUTION: According to a method of manufacturing dispersion liquid of the present invention, composite particles containing a tetrafluoroethylene based polymer and an inorganic material, and a dispersant are mixed under a non-pulverizing condition in a tank provided with at least one kind of a stirring mechanism selected from a group consisting of a stirring mechanism due to a stirring blade, a stirring mechanism due to rotation and a stirring mechanism due to revolution to disperse the composite particles in the dispersion medium to obtain the dispersion liquid, and a method for manufacturing a laminated body is configured to contact the dispersion liquid obtained according to the manufacturing method with a surface of a substrate, then heat for forming a polymer layer to obtain a laminated body having the substrate and the polymer layer.SELECTED DRAWING: None

Description

The present invention is a method for producing a dispersion liquid in which composite particles containing a tetrafluoroethylene polymer and an inorganic substance are dispersed in a dispersion medium, and a laminate in which the dispersion liquid obtained by the production method is applied to the surface of a substrate. Regarding the manufacturing method of.

As composite particles of a tetrafluoroethylene polymer and silica, composite particles having a core-shell structure having a tetrafluoroethylene polymer as a core and silica as a shell are known (see Patent Documents 1 and 2). Such composite particles can form a composition having a low viscosity, and are useful for forming a molded product having both physical characteristics such as low linear expansion and electrical characteristics.

International release 2017/135168 International Publication No. 2018/21279

However, since the tetrafluoroethylene polymer has extremely low polarity and low affinity with other components, it is highly difficult to interact with silica. Therefore, such composite particles tend not to be sufficiently stable in themselves.
The present inventors have such a tendency when a dispersion liquid (liquid composition) in which such composite particles are dispersed in a dispersion medium is mixed by using a dynamic stirring mechanism in order to obtain industrially and efficiently. I learned that is remarkable. Specifically, it was found that during the preparation thereof, foaming became intense and the dispersion stability decreased.
Furthermore, it was found that the physical properties of the molded product obtained from the molded product were not sufficiently expressed, and the surface smoothness of the molded product was lowered.

As a result of diligent studies, the present inventors have solved these problems by mixing and dispersing composite particles containing a tetrafluoroethylene polymer and an inorganic substance and a dispersion medium under predetermined conditions, and the composite particles are solved. It was found that a dispersion liquid stably dispersed in a dispersion medium can be obtained industrially and efficiently. Further, it has been found that when the dispersion liquid obtained under such conditions is brought into contact with the surface of the base material and heated, a laminate having excellent surface smoothness and good appearance can be obtained.
An object of the present invention is a dispersion liquid in which composite particles containing a tetrafluoroethylene polymer and an inorganic substance are mixed with a dispersion medium, and deformation and modification of the composite particles are suppressed when the composite particles are dispersed in the dispersion medium. Is provided with a manufacturing method that can be obtained industrially and efficiently. Further, an object of the present invention is to provide a method for producing a laminate having excellent surface smoothness and good appearance using the dispersion liquid obtained by the above-mentioned production method.

The present invention has the following aspects.
<1> At least one stirring mechanism selected from the group consisting of a composite particle containing a tetrafluoroethylene polymer and an inorganic substance and a dispersion medium, a stirring mechanism by a stirring blade, a stirring mechanism by rotation, and a stirring mechanism by revolution. A method for producing a dispersion liquid, which comprises mixing under non-pulverized conditions in a provided tank and dispersing the composite particles in the dispersion medium to obtain a dispersion liquid.
<2>
The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320 ° C. and containing 1 to 5 mol% of units based on perfluoro (alkyl vinyl ether) with respect to all units. The manufacturing method described in.
<3>
The production method according to <1> or <2>, wherein the tetrafluoroethylene polymer further has a polar functional group.
<4>
The production method according to any one of <1> to <3>, wherein the inorganic substance is silica.
<5>
The production method according to any one of <1> to <4>, which is a composite particle having an average particle diameter of 2 μm or more and 10 μm or less.
<6>
The production method according to any one of <1> to <5>, wherein the composite particles contain 20 to 80 parts by mass of the inorganic substance with respect to 100 parts by mass of the tetrafluoroethylene polymer.
<7>
The production method according to any one of <1> to <6>, wherein the composite particles have the tetrafluoroethylene polymer as a core and the inorganic substance on the surface of the core.
<8>
The production method according to <7>, wherein the core of the tetrafluoroethylene polymer and the inorganic substance are each in the form of particles.
<9>
The production method according to <7> or <8>, wherein the average particle size of the core is larger than the average particle size of the inorganic substance.
<10>
The production method according to any one of <1> to <9>, wherein the dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters.
<11>
The production method according to any one of <1> to <10>, which does not substantially contain a surfactant.
<12>
The production method according to any one of <1> to <11>, wherein the content of the composite particles is 25% by mass or more.
<13>
The production method according to any one of <1> to <12>, wherein the dispersion layer ratio of the dispersion liquid is 60% or more.
<14>
The production method according to any one of <1> to <13>, wherein the composition containing at least one of another resin or an inorganic filler is mixed.
<15>
The dispersion liquid obtained by the production method according to any one of <1> to <14> is brought into contact with the surface of the base material and heated to form a polymer layer, and the base material and the polymer layer are separated from each other. A method for manufacturing a laminated body, which obtains the laminated body having the same.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing a dispersion liquid in which the stability of the composite particles is sufficient when the composite particles containing the tetrafluoroethylene polymer and the inorganic substance are dispersed in the dispersion medium. Further, according to the present invention, there is provided a method for producing a laminate having excellent surface smoothness and good appearance by using the dispersion liquid obtained by the above-mentioned production method.

The following terms have the following meanings.
"D50" is an average particle diameter, which is a volume-based cumulative 50% diameter of an object (particle) obtained by a laser diffraction / scattering method. That is, the particle size distribution of the object is measured by the laser diffraction / scattering method, the cumulative curve is obtained with the total volume of the group of particles of the object as 100%, and the particles at the point where the cumulative volume is 50% on the cumulative curve. The diameter.
“D90” is the volume-based cumulative 90% diameter of the object, which is similarly measured.
The "melting temperature (melting point)" is the temperature corresponding to the maximum value of the melting peak of the polymer measured by the differential scanning calorimetry (DSC) method.
The "glass transition point (Tg)" is a value measured by analyzing a polymer, cured product or elastomer by a dynamic viscoelasticity measurement (DMA) method.
The "viscosity" is a value obtained by measuring the dispersion liquid at 25 ° C. and a rotation speed of 30 rpm using a B-type viscometer. The measurement is repeated 3 times, and the average value of the measured values for 3 times is used.
The "thixo ratio" is a value calculated by dividing the viscosity η ₁ obtained by measuring the dispersion liquid under the condition of a rotation speed of 30 rpm by the viscosity η ₂ obtained by measuring the dispersion liquid under the condition of a rotation speed of 60 rpm ( η ₁ / η ₂ ).
The "unit" in the polymer may be an atomic group formed directly from the monomer, or may be an atomic group in which a part of the structure is converted by treating the obtained polymer by a predetermined method. The unit based on the monomer A contained in the polymer is also simply referred to as "monomer A unit".
The "dispersion layer ratio" is the height of the entire dispersion in the screw tube and the dispersion layer before and after standing when 18 mL of the dispersion is placed in a screw tube having an internal volume of 30 mL and allowed to stand at 25 ° C. for 14 days. It is a value calculated by the following formula from the height of. If the dispersed layer is not confirmed after standing and there is no change in the state, it is assumed that the height of the entire dispersion liquid does not change, and the dispersed layer ratio is 100%. The larger the dispersion layer ratio, the better the dispersion stability.
Dispersion layer ratio (%) = (height of dispersion layer) / (height of the entire dispersion) × 100

The method for producing a dispersion liquid of the present invention (hereinafter, also referred to as “this method”) is a composite particle containing a tetrafluoroethylene polymer (hereinafter, also referred to as “F polymer”) and an inorganic substance (hereinafter, “this composite”). (Also referred to as “particles”) and the dispersion medium are not pulverized in a tank equipped with at least one stirring mechanism selected from the group consisting of a stirring mechanism by a stirring blade, a stirring mechanism by rotation and a stirring mechanism by revolution. This is a method of obtaining a dispersion liquid by mixing under the above conditions and dispersing the composite particles in the dispersion medium.
Further, in the method for producing a laminate of the present invention (hereinafter, also referred to as “the present production method”), the dispersion obtained by the present method is brought into contact with the surface of the substrate and heated to form a polymer layer. , A method for obtaining a laminate having the substrate and the polymer layer.

The F polymer is a highly rigid polymer, has a low surface energy, and its powders tend to aggregate with each other. Therefore, it is difficult to obtain a dispersion liquid containing F polymer particles and having excellent dispersion stability, and in order to improve the dispersibility, a method of mixing with a dispersion medium by applying high shear is generally adopted. However, it is also considered that the F polymer is easily denatured in the dispersion when mixed with the dispersion medium under high shear. In particular, when composite particles containing an F polymer and an inorganic substance are mixed under high shear, the inorganic substance and the F polymer strongly collide with each other, so that the composite particles are likely to be deformed or the F polymer is easily modified. In addition, foaming and agglomeration are likely to occur due to the entrainment of air.
In this method, the composite particles containing the F polymer and the inorganic substance are mixed with the dispersion medium under appropriate shearing conditions to suppress the deformation of the composite particles and the modification of the F polymer in the dispersion liquid, and to entrain air. Foaming and agglomeration due to Therefore, the dispersion obtained by this method is considered to be excellent in dispersibility and dispersion stability. Further, it is considered that the inorganic substance is uniformly dispersed in the polymer layer formed from the dispersion liquid, and the laminated body highly expresses the physical properties of the F polymer and the inorganic substance.

The F polymer may be heat-meltable or non-heat-meltable, but is preferably heat-meltable.
When the F polymer is thermally meltable, its melting temperature is preferably 260 ° C. to 320 ° C., more preferably 285 ° C. or higher and 320 ° C. or lower.
The glass transition point of the F polymer is preferably 75 to 125 ° C, more preferably 80 to 100 ° C.
The melt viscosity of the F polymer is preferably 1 × 10 ² to 1 × 10 ⁶ Pa · s at 380 ° C., more preferably 1 × 10 ³ to 1 × 10 ⁶ Pa · s.
If the melting temperature, glass transition point, or melting viscosity of the F polymer is within such a range, an appropriate tip force is likely to be applied when mixing with the dispersion medium.

Examples of the F polymer include polytetrafluoroethylene (hereinafter, also referred to as PTFE), tetrafluoroethylene-based units (hereinafter, also referred to as TFE units) and perfluoro (alkyl vinyl ether) (hereinafter, also referred to as PAVE) units (hereinafter, also referred to as PAVE). Polymers containing PAVE units (hereinafter also referred to as PFA) or copolymers containing units based on TFE and hexafluoropropylene (hereinafter also referred to as FEP) are preferable, PFA or FEP is more preferable, and PFA is even more preferable. These polymers may further contain units based on other comonomeres.
As the PAVE, CF ₂ = CFOCF ₃ , CF ₂ = CFOCF ₂ CF ₃ or CF ₂ = CFOCF ₂ CF ₂ CF ₃ (hereinafter, also referred to as PPVE) is preferable, and PPVE is more preferable.

The F polymer preferably has a polar functional group.
As the polar functional group, a hydroxyl group-containing group, a carbonyl group-containing group and a phosphono group-containing group are preferable, and a hydroxyl group-containing group and a carbonyl group-containing group are more preferable, and a carbonyl group is more preferable from the viewpoint of easily enhancing physical properties such as dispersibility of the particles. The containing group is more preferable.

As the hydroxyl group-containing group, an alcoholic hydroxyl group-containing group is preferable, and —CF ₂ CH ₂ OH, —C (CF ₃ ) ₂ OH and 1,2-glycol group (—CH (OH) CH ₂ OH) are more preferable.
Examples of the carbonyl group-containing group include a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC (O) NH ₂ ), an acid anhydride residue (-C (O) OC (O)-), and the like. An imide residue (-C (O) NHC (O)-etc.) and a carbonate group (-OC (O) O-) are preferable, and an acid anhydride residue is more preferable.

The F polymer preferably has a melting temperature of 260 to 320 ° C., contains PAVE units, and preferably contains 1 to 5 mol% of PAVE units relative to all units, preferably contains TFE units and PAVE units, and contains polar functional groups. A polymer (1) having PAVE units or a polymer (2) containing TFE units and PAVE units, containing 2 to 5 mol% of PAVE units with respect to all monomer units, and having no polar functional group is more preferable. When the dispersion liquid containing these polymers is applied to a substrate to form an F polymer layer, microspherulites are formed in the F polymer layer, so that the characteristics of the obtained laminate can be easily improved.

The polar functional group contained in the polymer (1) may be contained in the unit contained in the polymer, or may be contained in the terminal group of the polymer main chain. Examples of the latter polymer include polymers having a polar functional group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and a polymer having a polar functional group prepared by plasma treatment, ionization line treatment, radiation treatment, or the like. Be done.
If the F polymer is the polymer (1), in the present composite particles, the polymer (1) and the inorganic substance not only easily adhere physically but also chemically easily adhere to each other, and when mixed with the dispersion medium. In addition, the modification of the composite particles is suppressed. Further, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium more industrially and efficiently.

The polymer (1) contains 93 to 98.9 mol% of TFE units, 1 to 5 mol% of PAVE units and 0.01 to 2 mol% of units based on monomers having polar functional groups, based on all units. It is preferable to contain each.
Further, as the monomer having a polar functional group, itaconic anhydride, citraconic anhydride and 5-norbornen-2,3-dicarboxylic acid anhydride (hereinafter, also referred to as “NAH”) are preferable.
Specific examples of the polymer (1) include the polymers described in International Publication No. 2018/16644.

The polymer (2) is composed of only TFE units and PAVE units, and preferably contains 95 to 98 mol% of TFE units and 2 to 5 mol% of PAVE units with respect to all the units.
The content of PAVE units in the polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, based on all the units.
The fact that the polymer (2) does not have polar functional groups means that the number of polar functional groups possessed by the polymer is less than 500 per 1 × 10 ⁶ carbon atoms constituting the polymer main chain. Means that The number of the polar functional groups is preferably 100 or less, more preferably less than 50. The lower limit of the number of polar functional groups is usually 0.

The polymer (2) may be produced by using a polymerization initiator, a chain transfer agent, or the like that does not generate a polar functional group as the terminal group of the polymer chain, and the polar functional group derived from the polymerization initiator may be used in the polymer chain. A polymer having a polar functional group such as a polymer having a terminal group may be fluorinated to produce the polymer.
Examples of the fluorination treatment method include a method using fluorine gas (see JP-A-2019-194314).

The composite particles may contain a polymer other than the F polymer. However, the ratio of the F polymer to the polymer contained in the particles is preferably 80% by mass or more, more preferably 100% by mass.
Examples of the polymer other than the F polymer include heat-resistant resins such as aromatic polyester, polyamide-imide, thermoplastic polyimide, polyphenylene ether, and polyphenylene oxide.

The inorganic substances in the composite particles are preferably oxides, nitrides, simple metals, alloys and carbons, such as silicon oxide (silica), beryllium oxide, cerium oxide, alumina, soda alumina, magnesium oxide, zinc oxide and titanium oxide. Metal oxides, boron nitride, and magnesium metasilicate (steatite) are more preferred, and inorganic oxides containing at least one element selected from aluminum, magnesium, silicon, titanium, and zinc are more preferred, silica, oxidation. Titanium, zinc oxide, steatite and boron nitride are particularly preferred, with silica being most preferred. Further, the inorganic substance may be ceramics. As the inorganic substance, one kind may be used, or two or more kinds may be mixed and used. When two or more kinds of inorganic substances are mixed, two kinds of silica may be used, or silica and other metal oxides may be used.

Such inorganic substances tend to have an enhanced interaction with the F polymer. Further, in a molded product such as an F polymer layer and a film, which will be described later, which are formed from the present composite particles, physical characteristics based on an inorganic substance are remarkably likely to be exhibited.
The inorganic substance in the composite particles preferably contains silica.
The content of silica in the inorganic substance is preferably 50% by mass or more, more preferably 75% by mass. The silica content is preferably 100% by mass or less.

It is preferable that at least a part of the surface of the inorganic substance is surface-treated.
Examples of the surface treatment agent used for such surface treatment include polyhydric alcohols such as trimethylolethane, pentaeristol, and propylene glycol, saturated fatty acids such as stearic acid and lauric acid, or esters thereof, and amines such as alkanolamine, trimethylamine, and triethylamine. , Paraffin wax, silane coupling agent, silicone, polysiloxane, aluminum, silicon, zirconium, tin, titanium, antimony and other oxides, their hydroxides, their hydrated oxides, their phosphates. Be done.

Silane coupling agents include 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-. Ixylpropyltriethoxysilane is preferred.

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 likely to be enhanced. Further, in the layer of the F polymer or the like, the inorganic substance and the F polymer are more uniformly distributed, and it is easy to balance the physical properties of both.

Specific examples of inorganic substances include silica filler ("Admafine (registered trademark)" series manufactured by Admatex Co., Ltd.) and zinc oxide surface-treated with an ester such as propylene glycol dicaprate (manufactured by Sakai Chemical Industry Co., Ltd.). FINEX (registered trademark) "series, etc.), spherical fused silica (Denka's" SFP (registered trademark) "series, etc.), rutile-type titanium oxide coated with polyhydric alcohol and inorganic substances ("Ishihara Sangyo Co., Ltd." Typake (registered trademark) "series, etc.), rutile-type titanium oxide surface-treated with alkylsilane ("JMT (registered trademark)" series manufactured by Teika, etc.), hollow silica filler ("E-" manufactured by Pacific Cement Co., Ltd.) SPHERES "series, Nittetsu Mining Co., Ltd." Sirinax "series, Emerson & Cumming Co., Ltd." Ecocos Fire "series, Nippon Aerosil Co., Ltd. hydrophobic AEROSIL series" RX200 ", etc.), Tarkufiller (manufactured by Nippon Tarku Co., Ltd.) "SG" series, etc.), Steatite filler ("BST" series manufactured by Nippon Tarku, etc.), Boron nitride filler ("UHP" series manufactured by Showa Denko Co., Ltd., "Denka Boron Night Ride" series manufactured by Denka Co., Ltd. ( "GP", "HGP" grade), etc.).

The shape of the inorganic substance is preferably granular, more preferably spherical, needle-shaped (fibrous), and plate-shaped (pillar). Specific shapes of inorganic substances include spherical, scale-like, layered, leaf-like, apricot kernel-like, columnar, chicken crown-like, equiaxed, leaf-like, mica-like, block-like, flat plate-like, wedge-like, rosette-like, and mesh-like. , Square column, preferably spherical and scaly. When an inorganic substance having such a shape is used, the uniformity of the distribution of the inorganic substance in the layer of the F polymer or the like is improved, and it is easy to enhance its function.

The spherical inorganic substance is preferably substantially spherical. In the inorganic particles in this case, the ratio of the minor axis to the major axis is preferably 0.5 or more, more preferably 0.8 or more. The above ratio is preferably less than 1. By using such highly spherical inorganic particles, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium more industrially and efficiently. Further, in a molded product such as a layer of F polymer, the inorganic substance and the F polymer are more uniformly distributed, and it is easier to balance the physical properties of both.

The aspect ratio of the scaly inorganic substance is preferably 5 or more, and more preferably 10 or more. The aspect ratio is preferably 1000 or less.
The average major axis (average value of the diameter in the longitudinal direction) of the scaly inorganic substance is preferably 1 μm or more, and 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 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, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium more industrially and efficiently. Further, in the layer of the F polymer or the like, the inorganic substance and the F polymer are more uniformly distributed, and it is easier to balance the physical properties of both.

The scaly inorganic substance may have a single-layer structure or a multi-layer structure.
Examples of the latter inorganic substance include an inorganic substance having a hydrophobic layer on the surface and a hydrophilic layer inside. Specific examples thereof include an inorganic substance having a hydrophobic layer, a hydrophilic layer or a water-containing layer, and a hydrophobic layer in this order. The water content of the hydrophilic layer is preferably 0.3% by mass or more. In this case, not only the dispersed state of the composite particles in the dispersion liquid is easy to be stable, but also the orientation of the inorganic substance in the layer of the F polymer is further enhanced, and the physical properties of the F polymer and the physical properties of the inorganic substance are highly provided. It is easy to obtain a layer of F polymer or the like.

The average particle size of the composite particles, D50, is preferably 40 μm or less, more preferably 10 μm or less, further preferably 6 μm or less, and particularly preferably 4 μm or less. The D50 of the composite particles is preferably 0.01 μm or more, more preferably 0.1 μm or more, still more preferably 1 μm or more.
The D90 of the present composite particle is preferably 20 μm or less, more preferably 10 μm or less.
When D50 and D90 of the present composite particles are within such a range, the dispersion stability of the present composite particles in the dispersion medium and the physical properties of the F polymer layer obtained from the dispersion liquid are more likely to be improved. Further, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium more industrially and efficiently.

The amount of the inorganic substance in the composite particles is preferably 20 to 80 parts by mass with respect to 100 parts by mass of the F polymer. The amount of the inorganic substance in the particles is more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, based on 100 parts by mass of the F polymer. The amount of the inorganic substance in the particles is more preferably 60 parts by mass or less, still more preferably 50 parts by mass or less, based on 100 parts by mass of the F polymer.

This composite particle is a method of colliding F polymer particles and inorganic particles in a suspended state under heating conditions (hereinafter, also referred to as "dry method A"), and F polymer particles and inorganic particles. , A method of colliding in a pressed or sheared state (hereinafter, also referred to as "dry method B"), a method of bringing F polymer particles into contact with inorganic particles to coagulate the F polymer particles (hereinafter, "wet method"). It is also described as "law"). Drywall method A may also be referred to as hybridization treatment.

Preferable embodiments of the composite particles include an F polymer as a core and an inorganic substance attached to the surface of the core (hereinafter, also referred to as “Aspect I”), and an inorganic substance as a core on the surface of the core. An embodiment to which the F polymer is attached (hereinafter, also referred to as “Aspect II”) can be mentioned.
Here, the "core" means a core (central part) necessary for forming the particle shape of the present composite particle, and does not mean the main component in the composition of the present composite particle.
The inorganic substance or F-polymer deposit that adheres to the surface of the core may adhere to only a part of the surface of the core, or may adhere to most or the entire surface thereof. In the former case, it can be said that the deposits cling to the surface of the core like dust, in other words, a large part of the surface of the core is exposed. In the latter case, it can be said that the deposits are evenly sprinkled on the surface of the core or are in a state of covering the surface of the core, and the composite particles are the core and the shell covering the core. It can be said that it has a core-shell structure consisting of.

In the case of the aspect I, it is preferable that the core of the F polymer and the inorganic substance are each in the form of particles. In this case, since the inorganic substance having a hardness higher than that of the F polymer is exposed on the surface of the particles, the fluidity is increased and the handleability thereof is likely to be improved.
In the case of the aspect I, the core of the F polymer may be composed of a single particle of the F polymer, or may be composed of an aggregate of the particles of the F polymer.
The composite particles of the aspect I are preferably produced 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 to set the amount of the F polymer particles to be larger than the amount of the inorganic particles. If the particles are produced by the dry method A or the dry method B with such a relationship set, the particles of the aspect I can be easily obtained.

In the present composite particle of the aspect I, the D50 of the core of the F polymer is larger than the D50 of the inorganic particle, and the mass of the F polymer occupying the D50 is larger than the mass of the inorganic substance. In this case, the surface of the core of the F polymer is covered with a larger amount of inorganic particles, and the particles of Embodiment I will have a core-shell structure. In this case, the aggregation of the F powder particles is suppressed, and it is easy to obtain the present composite particles in which the inorganic particles are attached to the core composed of the single F powder particles.

In the aspect I, the particles of the inorganic substance are preferably spherical, and more preferably substantially true spherical. Approximately spherical means that when the particles are observed with a scanning electron microscope (SEM), the ratio of the minor axis to the major axis is 0.5 or more, and the proportion of spherical particles is 95% or more. do. In the inorganic particles in this case, the ratio of the minor axis to the major axis is preferably 0.6 or more, more preferably 0.8 or more. The above ratio is preferably less than 1. Here, the term "spherical" includes not only a true spherical shape but also a slightly distorted spherical shape.
When such highly spherical inorganic particles are used, the inorganic substance and the F polymer are more uniformly distributed in a molded product such as a polymer layer, and it is easier to balance the physical properties of both.

In the aspect I, the D50 of the inorganic particles is preferably in the range of 0.001 to 1 μm, more preferably 0.01 to 0.5 μm, still more preferably 0.05 to 0.3 μm. If it is within the range where D50 is applied, the handleability and fluidity of the particles are likely to be improved, and the dispersion stability is likely to be improved.
Further, the particle size distribution of the inorganic particles is preferably 3 or less, and more preferably 2.9 or less, using the value of D90 / D10 as an index. Here, "D10" is a volume-based cumulative 10% diameter of the object, which is measured in the same manner as D50 and D90. When the particle size distribution is narrow, it is preferable from the viewpoint that the fluidity of the obtained particles can be easily controlled.

In the aspect I, it is preferable that at least a part of the surface of the inorganic particles is surface-treated, and it is more preferable that the surface is treated with a silazane compound such as hexamethyldisilazane, a silane coupling agent, or the like. .. Examples of the silane coupling agent include the above-mentioned compounds.

In the aspect I, one kind of inorganic particles may be used, or two or more kinds may be mixed and used. When two kinds of inorganic particles are mixed and used, the average particle diameter of each inorganic particle may be different from each other, and the mass ratio of the content of each inorganic particle can be appropriately set according to the desired function.

Further, in the case of the aspect I, it is preferable that some of the particles of the inorganic substance are embedded in the core of the F polymer. As a result, the adhesion of the inorganic particles to the core of the F polymer is further improved, and the fall of the inorganic particles from the present particles is less likely to occur. That is, the stability of the particles is further improved.
In the particles of Embodiment I, the D50 of the core of the F polymer 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 even more preferably 10 μm.
In the present particles of the aspect I, 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 1 μm, more preferably 0.1 μm.
In the present particles of the aspect I, the D50 of the inorganic particles is preferably 0.001 to 0.5, more preferably 0.01 to 0.3, and 0.1 to 0, based on the D50 of the core of the F polymer. .2 is more preferable. Specifically, it is preferable that the D50 of the core of the F powder is more than 1 μm and the D50 of the inorganic particles is 0.5 μm or less.

When the composite particles are measured by X-ray photoelectron spectroscopy (hereinafter, also referred to as ESCA), the amount of silicon atoms with respect to the amount of fluorine atoms in the vicinity of the surface is preferably 1 or more. ESCA is a method for quantifying the amount of elements present on the surface of particles and the like, and it is possible to quantify each element such as carbon (C), oxygen (O), fluorine (F), and silicon (Si).
In the present invention, the vicinity of the surface is defined as a depth of 2 to 8 nm from the surface. In the present invention, the element existing at such a depth is measured from the surface of the composite particle by ESCA, and the amount of silicon atom and the amount of fluorine atom are quantified. The composite particles preferably have a value of 1 or more, and more preferably 1.2 or more, obtained by dividing the amount of silicon thus quantified by the amount of fluorine. In this case, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium more industrially and efficiently.

The composite particles may be further surface-treated depending on the physical characteristics of the inorganic substance adhering to the surface. Specific examples of such surface treatment include a method of surface-treating the composite particles of Embodiment I in which the inorganic substance contains silica with a siloxane such as polydimethylsiloxane or a silane coupling agent.
Such surface treatment can be carried out by dispersing the present composite particles in a liquid, mixing them with a siloxane or a silane coupling agent, reacting the siloxanes or the silane coupling agent, and recovering the present composite particles.
As the silane coupling agent, the above-mentioned silane coupling agent having a functional group is preferable.
According to such a method, not only the amount of surface silica of the composite particles can be adjusted, but also the surface physical characteristics thereof can be further adjusted.

The dispersion medium in the present invention is a liquid compound that is inert at 25 ° C. The dispersion medium may be water or a non-aqueous dispersion medium. The dispersion medium may be one kind or two or more kinds. In this case, it is preferable that the dissimilar dispersion media are compatible with each other.

The boiling point of the dispersion medium is preferably 125 to 250 ° C. In this range, when the dispersion medium is removed from the dispersion liquid obtained by this method, the composite particles are highly fluidized and densely packed, and as a result, a dense F polymer layer or the like is likely to be formed.
As the dispersion medium, at least one liquid compound selected from the group consisting of water, amides, ketones and esters is preferable, and water and N-methyl-2 are preferable, from the viewpoint of enhancing the dispersion stability of the complex particles in the dispersion liquid. -Pyrrolidone, γ-butyrolactone, methyl ethyl ketone, cyclohexanone and cyclopentanone are more preferred.

When the 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 composite particles is composed of an amino group, a vinyl group and a (meth) acryloyloxy group. It is preferably surface-treated with a silane coupling agent having at least one group selected from the above group, and more preferably surface-treated with phenylaminosilane.
When the dispersion medium contains a non-polar solvent such as toluene, at least a part of the surface of the inorganic substance in the composite particles is preferably hydrophobized, and is selected from the group consisting of an alkyl group and a phenyl group. It is preferably surface-treated with a silane coupling agent having at least one group.
When the dispersion medium contains a protic polar solvent such as water, it is preferable that the inorganic substances in the composite particles are not surface-treated.
In the case of such a combination of the dispersion medium and the inorganic substance, the dispersion liquid obtained by this method tends to have excellent dispersion stability.

In this method, the composite particles and the dispersion medium are not pulverized in a tank equipped with at least one stirring mechanism selected from the group consisting of a stirring mechanism by a stirring blade, a stirring mechanism by rotation, and a stirring mechanism by revolution. It is a method of obtaining a dispersion liquid by mixing under the conditions and dispersing the composite particles in the dispersion medium.
The stirring mechanism by the stirring blade is a mechanism in which a uniaxial or multi-axis stirring blade or a rotor equipped with a stirring blade receives rotational energy from a drive unit such as a motor to agitate an object to be agitated in a tank. The stirring blade may stir the object from either the upper part, the lower part, or the lateral part. Rotational energy may be received directly from the drive shaft of the motor, or may be indirectly received from magnetic force or the like by rotating a magnet or the like.

The rotation-based agitation mechanism is a mechanism in which a tank containing an object to be agitated rotates around a rotation axis to agitate the object. The direction of the rotation axis may be any direction with respect to the tank. On the other hand, the stirring mechanism by revolution is a mechanism in which the tank orbits around a fixed point outside the tank containing the stirring object to stir the object. The layer may be vertical, horizontal or inclined with respect to the plane of revolution.

The composite particles and the dispersion medium are stirred in a tank having any of the above-mentioned stirring mechanisms. The tank may have two or more of the stirring mechanisms. For example, a tank having a stirring mechanism by a stirring blade and a stirring mechanism by rotation, a tank having a stirring mechanism by a stirring blade and a stirring mechanism by revolution, a tank having a stirring mechanism by rotation and rotation, a stirring mechanism by a stirring blade, and a stirring mechanism by rotation. And a tank having a stirring mechanism by revolution may be used.

The tanks equipped with the stirring mechanism include a Henschel mixer, a tank equipped with a stirrer having propeller blades, a tank equipped with a stirrer having anchor blades, a planetary mixer, a rotation / revolution mixer, and a mixer for rotating the tank (limited). An example is "Maze Maze Man" (registered trademark) manufactured by Misugi Co., Ltd.).

The composite particles and the dispersion medium are mixed under non-pulverized conditions in a tank having at least one of the stirring mechanisms.
The non-pulverized condition is a condition in which the surface area of the present composite particles is generally maintained before and after mixing. For example, when the surface area of the present composite particles before mixing is 1, the surface area after mixing is from 1. The conditions are within the range of 1.2.

In order to achieve the non-pulverization condition, the mixing conditions of the tank having the stirring mechanism may be appropriately set, but it is preferable to stir only by the stirring mechanism or a combination thereof. Also, when stirring, do not use an inner piece like a ball used in a ball mill or a baffle provided on the wall of the tank to improve stirring efficiency, the inner wall of the tank is smooth, and in the case of a tank with a stirring mechanism. It is preferable that the stirring blade is not equipped with a scraper or the like and the stirring blade and the inner wall of the tank are not brought into contact with each other.
While these stirring conditions are factors that reduce the shearing force applied to the composite particles during mixing, they are factors that suppress the deformation of the composite particles and the modification of the F polymer, further enhancing the high dispersion of the composite particles. Promote. As a result, it is easy to obtain a dispersion liquid in which the composite particles are dispersed in the dispersion medium under these stirring conditions more industrially and efficiently.

In this method, the temperature of mixing of the composite particles and the dispersion medium is not particularly limited as long as the composite particles are uniformly dispersed, but is usually carried out at 20 ° C. or higher. Further, the mixing is carried out at a temperature lower than the boiling point of the dispersion medium, and it is preferable to carry out the mixing at 100 ° C. or lower.

In a tank having at least one of the stirring mechanisms, the composite particles and the dispersion medium are stirred under the non-pulverized conditions, and the composite particles are dispersed in the dispersion medium to deform the composite particles and obtain F. A dispersion liquid having excellent dispersibility and dispersion stability can be obtained, in which denaturation of the polymer in the dispersion liquid is suppressed and foaming and aggregation due to air entrainment are suppressed.

The content of the composite particles in the dispersion obtained by this method is preferably 25% by mass or more, more preferably 30% by mass to 60% by mass, with the dispersion as 100% by mass.
This method is suitable for producing a dispersion having a relatively high concentration of the composite particles.

Since the dispersion liquid obtained by this method is excellent in dispersibility and dispersion stability, it is usually preferable that the dispersion liquid does not contain substantially the added surfactant. If a surfactant is contained, the appearance of the layer may be inferior when the F polymer layer is formed from the dispersion liquid as described later. The fact that the surfactant is substantially not contained means that the concentration of the surfactant in the dispersion does not exceed 1% by mass, and the amount of the surfactant in the obtained dispersion is 1% by mass. It is as follows. The amount of the surfactant is preferably 0.5% by mass or less, more preferably 0% by mass.

In this method, a composition containing another resin or an inorganic filler (hereinafter, also referred to as a third component) may be further mixed. The other resin may be an F polymer. Other resins include polytetrafluoroethylene (PTFE), polymers containing TFE units and PAVE units (PFA), polymers containing TFE units and units based on hexafluoropropylene (FEP), TFE units and based on ethylene. Polymer (ETFE) containing units, polyvinylidene fluoride (PVDF), polyimide, polyallylate, polysulfone, polyallylsulfone, polyamide, polyetheramide, polyphenylene ether, polyphenylenesulfide, polyallyl ether ketone, polyamideimide, liquid crystal. Examples thereof include polyester, liquid crystal polyesteramide, epoxy resin, maleimide resin and the like. The other resin may be dispersed or dissolved in the dispersion obtained by this method.
The other resin may be thermoplastic, may be thermosetting, and is preferably thermoplastic.
The other resin is preferably an F polymer or an aromatic polymer. As the aromatic polymer, aromatic polyimide is preferable.

As the inorganic filler, an embodiment similar to that of the above-mentioned inorganic substance can be exemplified.
The composition containing another resin or an inorganic filler is preferably liquid from the viewpoint of handleability at the time of addition and the ability to add a large amount.

In this method, as the third component, the third component and the present composite particles may be mixed in advance and mixed with the dispersion medium, or the third component and the dispersion medium may be mixed in advance and the present composite particles may be mixed. May be mixed with. Further, according to this method, the composite particles and the dispersion medium may be mixed under the above conditions, the composite particles may be dispersed in the dispersion medium, and then the third component may be further added and mixed.

In this method, in addition to the above components, tyxo-imparting agents, viscosity modifiers, defoaming agents, silane coupling agents, dehydrating agents, plasticizers, weather resistant agents, antioxidants, heat stabilizers, lubricants, antistatic agents , Whitening agents, colorants, conductive agents, mold release agents, surface treatment agents, flame retardants, various fillers and the like may be further added.

The viscosity of the dispersion obtained by this method is preferably 50 mPa · s or more, more preferably 100 mPa · s or more. The viscosity of the present composition is preferably 50,000 mPa · s or less, more preferably 1000 mPa · s or less, and even more preferably 800 mPa · s or less. In this case, since the present composition is excellent in coatability, it is easy to form a layer of F polymer having an arbitrary thickness.
The thixotropy of the dispersion obtained by this method is preferably 1 or more. The thixotropy of the dispersion obtained by this method is preferably 3 or less, more preferably 2 or less. In this case, the dispersion obtained by this method is not only excellent in coatability but also excellent in homogeneity, so that it is easy to form a more dense layer of F polymer or the like.

The dispersion layer ratio of the dispersion obtained by this method is preferably 60% or more, more preferably 70% or more. The upper limit of the dispersed layer ratio is 100%. As described above, the dispersion obtained by this method tends to be excellent in dispersibility and dispersion stability.

From the viewpoint of reducing the uniformity of the component distribution of the molded product obtained from the dispersion liquid by this method and suppressing voids, the foam volume ratio in the dispersion liquid is preferably less than 10%, more preferably less than 5%. The foam volume ratio is preferably 0% or more.
The foam volume ratio was measured by measuring the volume ( _VN ) of the dispersion liquid at standard atmospheric pressure and 20 ° C. and the combined volume ( _VV ) of the foam when the pressure was reduced to 0.003 MPa, and the following was measured. It is a value obtained by the calculation formula.
Foam volume ratio [%] = 100 × ( _{VV −} VN) / _VN .

In the present production method, the dispersion liquid obtained by this method (hereinafter, also referred to as “the main dispersion liquid”) is brought into contact with the substrate and heated to form a layer made of an F polymer (hereinafter, also referred to as “F layer”). Is formed to produce a laminate in which the base material is coated with the F layer. The contact method is, for example, a method of applying the present dispersion on the surface of the substrate, a method of immersing the substrate in the present dispersion and impregnating the substrate with the present dispersion, or a method of spraying the present dispersion on the substrate. And so on.

Examples of the base material include metal foil, resin film, woven fabric, non-woven fabric, fiber and the like. Preferable embodiments of the base material include a metal-clad laminate having a metal foil and an F layer formed on at least one surface thereof, and a multilayer film having a resin film and an F layer formed on at least one surface thereof. , A coated woven fabric obtained by impregnating a woven fabric or a nonwoven fabric with the present dispersion and coating the fibers in the woven fabric or the nonwoven fabric with an F layer. Further, the present dispersion may be brought into direct contact with the fiber and fired to coat the fiber with the F polymer.
The F layer may cover the entire surface of the base material or a part of the base material, and the F polymer may be attached to the surface of the base material. The F layer may have holes.

Examples of the metal foil include metal substrates such as copper, nickel, aluminum, titanium, and metal foils such as alloys thereof. Examples of the resin film include resin films such as polyimide, polyarylate, polysulfone, polyallyl sulfone, polyamide, polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, liquid crystal polyester, liquid crystal polyester amide, and F polymer, and fibers. A prepreg which is a precursor of a reinforced resin substrate can be mentioned. As the F polymer in the resin film, PTFE, PFA and FEP are preferable. The shape of these metal foils or resin films may be flat, curved, uneven, and may be foil, plate, film, or fibrous.
Specific examples of the laminate include a metal foil, a metal-clad laminate having an F layer on at least one surface of the metal foil, a polyimide film, and a multilayer film having an F layer on both surfaces of the polyimide film. Be done. These laminates are excellent in various physical properties such as electrical characteristics, and are suitable as a printed circuit board material or the like. Specifically, such a laminate can be used for manufacturing a flexible printed circuit board or a rigid printed circuit board.

The metal foil is preferably a copper foil. A metal-clad laminate in which the base material is a copper foil is particularly useful as a printed circuit board material.
The resin film is preferably a polyimide film or an F polymer film. A multilayer film, which is a laminate of films on which a base material is applied, is useful as an electric wire coating material and a printed circuit board material.

In the production of a metal-clad laminate having an F layer or a multilayer film having an F layer, it is sufficient that the F layer is formed on at least one side of the surface of the base material, and even if the F layer is formed on only one side of the base material. Often, the F layer may be formed on both sides of the base material. The surface of the base material may be surface-treated with a silane coupling agent or the like. When applying this dispersion, the spray method, roll coat method, spin coat method, gravure coat method, micro gravure coat method, gravure offset method, knife coat method, kiss coat method, bar coat method, die coat method, fountain Mayer bar method. , The application method of the slot die coating method can be used.

When the woven fabric is impregnated with the present dispersion and dried by heating, a coated woven fabric in which the woven fabric is coated with the F layer can be obtained. The woven fabric is preferably a glass fiber woven fabric, a carbon fiber woven fabric, an aramid fiber woven fabric or a metal fiber woven fabric, and more preferably a glass fiber woven fabric or a carbon fiber woven fabric. Examples of the method of impregnating the woven fabric with the present dispersion include a method of immersing the woven fabric in the present dispersion and a method of applying the present dispersion to the woven fabric.

When the present dispersion is brought into contact with the fiber surface and fired to attach the F layer to the fiber surface, a coated fiber in which the fiber is coated with the F layer can be obtained. Examples of the fiber include glass fibers such as E glass, D glass, L glass, S glass, T glass, Q glass, UN glass, NE glass, and spherical glass, aramid fibers, and polyolefins, which are used as reinforcing fibers of fiber reinforced plastics. Examples thereof include organic fibers such as fibers, modified polyphenylene ether fibers, vinylon fibers, rayon fibers, polyester fibers and natural fibers, boron fibers, carbon fibers and metal fibers.
The shape of the fiber may be chopped strand, surfing, roving or any of these mats, woven fabrics, non-woven fabrics and the like. Further, the fiber length and the cross-sectional shape of the fiber are not particularly limited.

By coating the above fibers with the F layer, a sizing effect of suppressing yarn breakage and fluffing of the fibers can be obtained. Therefore, this dispersion is suitably used as a sizing agent. When the present dispersion is used as a sizing agent, necessary additives may be appropriately added to the present dispersion depending on the fibers used. The fibers sized with this dispersion have excellent heat resistance and adhesiveness to other polymers.

The F layer is preferably formed by further firing the polymer after removing the dispersion medium by heating. The temperature for removing the dispersion medium is preferably a temperature equal to or lower than the boiling point of the dispersion medium, and more preferably a temperature 50 ° C. to 150 ° C. lower than the boiling point. For example, when N-methyl-2-pyrrolidone having a boiling point of about 200 ° C. is used, it is preferable to heat it at 150 ° C. or lower, preferably 100 to 120 ° C. For example, when water having a boiling point of about 100 ° C. is used, it is preferable to heat it at 90 ° C. or lower, preferably 70 to 80 ° C. It is preferable to blow air in the step of removing the dispersion medium.

After removing the dispersion medium, it is preferable to heat the substrate to a temperature range in which the polymer is fired to form an F layer, and it is preferable to fire the polymer in the range of, for example, 300 to 400 ° C. The F layer preferably contains a fired product of the F polymer.
The F layer is formed through a step of contacting the dispersion liquid with the substrate and a step of heating the dispersion liquid as described above. These steps may be performed once or twice or more. For example, the present dispersion is applied to a substrate, and the dispersion medium is removed by heating to form a film. The present dispersion may be further applied onto the formed film, the dispersion medium may be removed by heating, and the F polymer may be further fired by heating to form the film. From the viewpoint of easily obtaining a thick film having an excellent appearance, the steps of applying, drying and firing the present dispersion may be performed twice.

The thickness of the F layer is preferably 0.1 μm or more, and more preferably 1 μm or more. The upper limit of the thickness is preferably 200 μm. In this range, the F layer having excellent crack resistance can be easily formed.
The peel strength between the F layer and the substrate is preferably 10 mN / m or more, more preferably 15 mN / m or more. The peel strength is preferably 100 mN / m or less. By using this dispersion, such a laminate can be easily formed without impairing the physical properties of the F polymer in the F layer.
The porosity of the F layer is preferably 20% or less, more preferably 10% or less. The porosity is preferably 0.1% or more. The void ratio is determined by image processing to determine the void portion of the F layer from the SEM photograph of the cross section of the molded product observed using a scanning electron microscope (SEM), and the area occupied by the void portion is the F layer. It is the ratio (%) divided by the area. The area occupied by the void portion is obtained by approximating the void portion to a circle.

Examples of the structure of the metal-clad laminate or the multilayer film include a base material / F layer / base material / F layer / base material, a base material / base material / F layer / base material / base material, and the like. Each base material may be the same or different, and the base material or the F layer may further contain a glass cloth or a filler.
Such metal-clad laminates are useful as antenna parts, printed films, aircraft parts, automobile parts, sports equipment, food industry supplies, heat dissipation parts, paints, cosmetics, etc., and specifically, electric wires for aircraft and the like. Wire coating materials, enamel wire coating materials used for motors of electric vehicles, etc., electrical insulating tapes, insulating tapes for oil drilling, materials for printed boards, precision filtration membranes, ultrafiltration membranes, back-penetration membranes, ion exchange Separation membranes such as membranes, dialysis membranes, gas separation membranes, electrode binders for lithium secondary batteries, fuel cells, etc., copy rolls, furniture, automobile dashboards, covers for home appliances, load bearings, sliding shafts, valves, etc. Sliding members such as bearings, gears, cams, belt conveyors, food transport belts, tools such as shovels, shavings, cuttings, saws, boilers, hoppers, pipes, ovens, baking molds, dies, dies, toilet bowls, container covering materials. , Power devices, transistors, thyristors, rectifiers, transformers, power MOS FETs, CPUs, heat dissipation fins and metal heat dissipation plates.
More specifically, sealing materials for processing machines, vacuum ovens, plasma processing equipment, etc. that heat-treat under low oxygen, such as housings for personal computers and displays, electronic device materials, interior and exterior of automobiles, spattering and various dry etching. It is useful as a heat dissipation component in a processing unit such as a device.

Further, this dispersion is impregnated into an insulating layer of a printed wiring board, a heat interface material, a substrate for a power module, a coil used in a power device such as a motor, and dried to form a heat conductive heat-resistant coating layer. It can also be used for applications, applications for bonding ceramic parts and metal parts to each other in an in-vehicle engine, applications for imparting corrosion resistance to heat exchangers and fins or tubes constituting the heat exchangers.

Although the method for producing the dispersion liquid and the method for producing the laminate of the present invention have been described above, the present invention is not limited to the configuration of the above-described embodiment.
For example, the composite particles and the dispersion medium may be added to any other configuration or may be replaced with any configuration exhibiting the same function in the configuration of the above embodiment, respectively.
In addition, the method for producing the dispersion liquid and the method for producing the laminate of the present invention may additionally have any other step in the configuration of the above embodiment, respectively, or any step that produces the same action. May be replaced with.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
1. 1. Preparation of each component [composite particles]
Composite particle 1: F polymer 1 containing TFE unit, NAH unit and PPVE unit in this order at 97.9 mol%, 0.1 mol% and 2.0 mol% and having a polar functional group (melting temperature: 300). F polymer obtained by treating 70 parts by mass of particles (D50: 2.0 μm) of (° C.) and 30 parts by mass of substantially spherical silica filler 1 (D50: 0.25 μm) by a hybridization method. Spherical composite particles (D50: 3 μm) having a core-shell structure in which 1 is used as a core and a shell is formed by adhering silica filler 1 to the surface of the core.
Composite particle 2: 70 parts by mass of particles (D50: 1.8 μm) made of F polymer 2 (melting temperature 305 ° C) having no oxygen-containing polar group, consisting of TFE units and PPVE units, and substantially spherical silica. 30 parts by mass of filler 1 (D50: 0.25 μm) was treated with an F polymer 2 obtained by a hybridization method as a core, and silica filler 1 adhered to the surface of the core to form a shell. Spherical composite particles with core-shell structure (D50: 3 μm)
[Polyimide varnish]
Varnish 1: Varnish in which aromatic polyimide (PI1) is dissolved in NMP [liquid dispersion medium]
NMP: N-methyl-2-pyrrolidone

2. Preparation of dispersion (Example 1)
The composite particles 1, the varnish 1, and the NMP were put into a pot and stirred with a rotating revolution mixer for 1 hour, and the composite particles 1 (40 parts by mass), PI1 (1 part by mass), and NMP (59 parts by mass) were stirred. A dispersion liquid 1 containing the above was obtained. For the tank of the rotation / revolution mixer, a tank with a smooth inner surface was selected.
(Example 2)
The dispersion liquid 2 containing the composite particles 2 (40 parts by mass), PI1 (1 part by mass), and NMP (59 parts by mass) was prepared in the same manner as in Example 1 except that the composite particles 1 were changed to the composite particles 2. Obtained.
(Example 3)
The composite particles 2, the varnish 1, and the NMP were put into the pot, and the zirconia balls were put into the pot. Then, the pot was rolled at 150 rpm for 1 hour to obtain a dispersion liquid 3 containing composite particles 1 (40 parts by mass), PI1 (1 part by mass), and NMP (59 parts by mass).
3. 3. Evaluation 3-1. Evaluation of Dispersion Stability of Dispersion Solution 18 mL of each dispersion solution was placed in a screw tube having an internal volume of 30 mL and allowed to stand at 25 ° C. for 14 days. From the total height of the dispersion liquid in the screw tube and the height of the component dispersion layer before and after standing, the component dispersion layer ratio was calculated by the following formula.
Component dispersion layer ratio (%) = (height of component dispersion layer) / (total height of dispersion) × 100
If the sedimentation layer is not confirmed after standing and there is no change in the state, it is assumed that there is no change in the overall height of the dispersion liquid, and the component dispersion layer ratio is 100%.
The dispersion stability of the dispersion was evaluated according to the following criteria.
[Evaluation criteria]
〇: The component dispersion layer ratio is 80% or more.
Δ: The component dispersion layer ratio is 60% or more and less than 80%.
X: The component dispersion layer ratio is less than 60%.

3-2. Appearance Evaluation A liquid film was formed by applying the dispersion liquid 1 on the surface of a copper foil having a thickness of 18 μm by a roll-to-roll method by a gravure reverse method. Next, the copper foil on which the liquid film was formed was passed through a drying oven at 120 ° C. for 5 minutes and dried by heating. Then, the dry film was heated at 340 ° C. for 3 minutes in a far-infrared oven under a nitrogen atmosphere. As a result, the laminated body 1 in which the polymer layer having a thickness of 10 μm was formed on the surface of the copper foil was manufactured.
The laminate 2 or 3 was obtained in the same manner as the laminate 1 except that the dispersion 1 was changed to the dispersion 2 or 3.
The surface of the polymer layer of each laminate was visually observed and evaluated according to the following criteria.
〇: No agglomeration or powder falling on the surface, and smooth. Δ: Agglomeration or powder falling is seen on a part of the surface.
X: Aggregation or powder falling is observed on the entire surface.

The results of each evaluation are summarized in Table 1 below.

The dispersion obtained by the method for producing a dispersion of the present invention is excellent in dispersibility and dispersion stability. Such a dispersion can be used for producing a laminate having physical characteristics based on an F polymer and properties based on an inorganic substance. The laminate obtained by the method for producing a laminate of the present invention is useful as an antenna component, a printed substrate, an aircraft component, an automobile component, a sports tool, a food industry article, a paint, a cosmetic, and the like. Wire coating materials (aircraft wires, etc.), electrical insulating tapes, insulating tapes for oil drilling, materials for printed substrates, separation membranes (precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gases) Separation membranes, etc.), electrode binders (for lithium secondary batteries, fuel cells, etc.), copy rolls, furniture, automobile dashboards, covers for home appliances, sliding members (load bearings, sliding shafts, valves, bearings, gears, etc.) , Cams, belt conveyors, food transport belts, etc.), tools (shovels, shavings, cuttings, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, dies, toilet bowls, container covering materials.

Claims (15)

A tank equipped with at least one stirring mechanism selected from the group consisting of a stirring mechanism by a stirring blade, a stirring mechanism by rotation, and a stirring mechanism by revolution of composite particles containing a tetrafluoroethylene polymer and an inorganic substance and a dispersion medium. A method for producing a dispersion liquid, which comprises mixing under non-pulverized conditions and dispersing the composite particles in the dispersion medium to obtain a dispersion liquid. The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320 ° C. and containing 1 to 5 mol% of units based on perfluoro (alkyl vinyl ether) with respect to all units, according to claim 1. The manufacturing method described. The production method according to claim 1 or 2, wherein the tetrafluoroethylene polymer further has a polar functional group. The production method according to any one of claims 1 to 3, wherein the inorganic substance is silica. The production method according to any one of claims 1 to 4, wherein the composite particles have an average particle diameter of 2 μm or more and 10 μm or less. The production method according to any one of claims 1 to 5, wherein the composite particles contain 20 to 80 parts by mass of the inorganic substance with respect to 100 parts by mass of the tetrafluoroethylene polymer. The production method according to any one of claims 1 to 6, wherein the composite particles have the tetrafluoroethylene polymer as a core and the inorganic substance on the surface of the core. The production method according to claim 7, wherein the core of the tetrafluoroethylene polymer and the inorganic substance are each in the form of particles. The production method according to claim 7 or 8, wherein the average particle size of the core is larger than the average particle size of the inorganic substance. The production method according to any one of claims 1 to 9, wherein the dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters. The production method according to any one of claims 1 to 10, which does not substantially contain a surfactant. The production method according to any one of claims 1 to 11, wherein the content of the composite particles is 25% by mass or more. The production method according to any one of claims 1 to 12, wherein the dispersion layer ratio of the dispersion liquid is 60% or more. The production method according to any one of claims 1 to 13, further comprising a composition containing at least one of another resin or an inorganic filler. The dispersion liquid obtained by the production method according to any one of claims 1 to 14 is brought into contact with the surface of a base material and heated to form a polymer layer, which has the base material and the polymer layer. A method for manufacturing a laminated body to obtain a laminated body.