Method for manufacturing aqueous dispersions and laminates

Abstract

An aqueous dispersion is provided, exhibiting excellent dispersion stability, mixing and workability during application, and surface smoothness of the resulting coating film; and a method for manufacturing a laminate obtained from the aforementioned aqueous dispersion is provided. An aqueous dispersion comprises: particles containing a tetrafluoroethylene-based polymer, a polydimethylsiloxane compound, hydrophobic silica, and water.

Description

[Technical Field]

[0001] This invention relates to an aqueous dispersion and a method for manufacturing a laminate obtained from the aforementioned aqueous dispersion. More specifically, this invention relates to an aqueous dispersion comprising a tetrafluoroethylene-based polymer and a method for manufacturing a laminate obtained from the aforementioned aqueous dispersion. [Previous Technology]

[0002] Tetrafluoroethylene polymers possess excellent physical properties such as electrical insulation, water and oil repellency, chemical resistance, and heat resistance. Therefore, dispersions containing their particles in water or organic solvents are useful as materials for forming resists, adhesives, electrical insulating layers, lubricants, inks, and coatings. However, tetrafluoroethylene polymers have low surface energy, and their particles tend to aggregate easily. Therefore, dispersions with excellent dispersion stability and low viscosity are being developed.

[0003] For example, Patent Document 1 discloses a non-aqueous dispersion containing tetrafluoroethylene polymer microparticles and fluorine additives.

[0004] [Prior Technology Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2015-199902 [Summary of the Invention]

[0005] Summary of the Invention [Problem to be Solved by the Invention] However, when the liquid dispersion medium is an aqueous dispersion of water containing tetrafluoroethylene-based polymer particles, it is prone to foaming and has low operability in the following situations: when preparing the dispersion, when mixing the dispersion with other components such as resin varnishes, and when applying the dispersion. Furthermore, in order to maintain the long-term stable storage of the dispersion, it is necessary to manage the liquid properties such as pH and viscosity in a complicated manner.

[0006] The inventors of this case discovered that by adding polydimethylsiloxane compounds and hydrophobic silica, an aqueous dispersion can be obtained, which has excellent dispersion stability, mixing and workability during application, and surface smoothness of the resulting coating film, and thus completed the present invention.

[0007] The present invention provides an aqueous dispersion with excellent dispersion stability, mixing, workability during application and surface smoothness of the resulting coating film, and provides a method for manufacturing a laminate obtained from the aforementioned aqueous dispersion.

[0008] [Means for Solving the Problem] The present invention has the following aspects. [1] An aqueous dispersion comprising: particles containing a tetrafluoroethylene polymer, a polydimethylsiloxane compound, hydrophobic silica, and water. [2] An aqueous dispersion of [1] wherein at least a portion of the aforementioned polydimethylsiloxane compound is a hydrophilic polydimethylsiloxane having polyoxyethylene ethyl groups. [3] An aqueous dispersion of [1] or [2] comprising a hydrophilic polydimethylsiloxane having polyoxyethylene ethyl groups and a hydrophobic polydimethylsiloxane with a viscosity of 10 to 100,000 mm² / s as the aforementioned polydimethylsiloxane compound. [4] An aqueous dispersion of any one of [1] to [3] wherein the aforementioned hydrophobic silica has a methanol wetting value of 30 to 75. [5] An aqueous dispersion of any one of [1] to [4], wherein the primary particle size of the aforementioned hydrophobic silica is 0.01 to 20 μm. [6] An aqueous dispersion of any one of [1] to [5], wherein the specific surface area of ​​the aforementioned hydrophobic silica is 100 to 700 m2 / g.

[0009] [7] An aqueous dispersion of any one of [1] to [6], wherein the content of the aforementioned tetrafluoroethylene-containing polymer particles is 30% by mass or more. [8] An aqueous dispersion of any one of [1] to [7], wherein, relative to 100 parts by mass of the aforementioned tetrafluoroethylene-containing polymer particles, the aforementioned polydimethylsiloxane compound contains 11 parts by mass or less, and the aforementioned hydrophobic silica contains 0.5 parts by mass or less. [9] An aqueous dispersion of any one of [1] to [8] further comprises a polyether compound.

[10] An aqueous dispersion of [9], wherein, relative to 100 parts by mass of the aforementioned tetrafluoroethylene-containing polymer particles, the aforementioned polyether compound contains 1 part by mass or less.

[11] An aqueous dispersion of any one of [1] to

[10] , wherein the aforementioned tetrafluoroethylene-containing polymer is a polymer having an oxygen-containing polar group.

[12] An aqueous dispersion of any one of [1] to

[11] comprises particles containing a hot-melt tetrafluoroethylene polymer and particles containing a non-hot-melt tetrafluoroethylene polymer as the aforementioned particles containing a tetrafluoroethylene polymer.

[0010]

[13] A method for manufacturing a laminate involves forming a layer of an aqueous dispersion as described in any one of [1] to

[12] on the surface of a substrate, and then heating the aqueous dispersion layer to remove water to form a layer containing a tetrafluoroethylene polymer on the surface of the substrate, thereby obtaining a laminate having the aforementioned tetrafluoroethylene polymer layer and the aforementioned substrate.

[14] The manufacturing method of

[13] involves firing the aforementioned tetrafluoroethylene polymer layer formed by heating to remove water.

[15] In the manufacturing method of

[13] or

[14] , the thickness of the aforementioned tetrafluoroethylene polymer layer is 10 μm or more.

[0011] The present invention provides an aqueous dispersion having excellent dispersion stability, operability when mixed with other materials and applied, and surface smoothness of the resulting coating film, and provides a method for manufacturing a laminate obtained from the aforementioned aqueous dispersion.

Implementation Method

[0012] [Forms for Implementing the Invention] The following terms have the following meanings. "Tetrafluoroethylene-based polymer" refers to a polymer containing units (hereinafter also referred to as "TFE units") with tetrafluoroethylene (hereinafter also referred to as "TFE units") as the main component, and is also abbreviated as "F polymer". "Hot-melting tetrafluoroethylene-based polymer" means: the aforementioned tetrafluoroethylene-based polymer, and a polymer with a melt flow rate of 1 to 1000 g / 10 min under a load of 49 N. It is also abbreviated as "hot-melting F polymer". "Glass transition point (Tg) of the polymer" is a value determined by analyzing the polymer using the dynamic viscoelasticity assay (DMA). "Melting temperature (melting point) of the polymer" is the temperature corresponding to the maximum value of the dissolution peak when the polymer is determined by the differential scanning calorimetry (DSC). "D50" refers to the average particle size of the particle aggregate, i.e., the powder, which is the cumulative 50% diameter based on the volume of the powder obtained by laser diffraction and scattering. That is, by measuring the particle size distribution of the powder using laser diffraction and scattering, a cumulative curve is obtained with the total volume of the powder set to 100%, and the particle size at the point where the cumulative volume is 50% of the cumulative diameter on this curve. "D90" refers to the cumulative volume particle size of the powder, which is the cumulative 90% diameter based on the volume of the powder obtained in the same way as "D50". "Monomer-based unit" means: an atomic group formed by monomer polymerization, with one molecule of the aforementioned monomer as the main component. The unit can be a unit directly formed through a polymerization reaction, or it can be a unit whose structure is transformed by processing the polymer. Hereinafter, the unit based on monomer a will be abbreviated as "monomer a unit".

[0013] The aqueous dispersion of the present invention (hereinafter also referred to as "this dispersion") comprises: particles containing F polymer (hereinafter also referred to as "F particles"), polydimethylsiloxane compound (hereinafter also referred to as "this siloxane"), hydrophobic silica (hereinafter also referred to as "this silica"), and water. Furthermore, the method for manufacturing the laminate of the present invention (hereinafter also referred to as "this method") is a method for manufacturing a laminate having a layer containing F polymer and a substrate (hereinafter also referred to as "this laminate"). This manufacturing method involves forming a layer of this dispersion on the surface of the substrate, and then heating and removing water from the aqueous dispersion layer to form a layer containing F polymer on the surface of the substrate.

[0014] The F polymer is a rigid polymer with very low affinity for other components. Therefore, aqueous dispersions containing F particles, with water as the liquid dispersion medium, are prone to foaming. Furthermore, F particles have low water wettability, resulting in poor operability in the following situations: when preparing themselves, when mixing them with other components such as resin varnishes, or when applying them. This dispersion suppresses foaming and exhibits excellent dispersion stability, operability, and long-term shelf life. The laminate formed from this dispersion possesses high electrical properties and other physical properties derived from the F polymer, and also exhibits excellent surface smoothness. The reason for this is not yet clear, but the idea is as follows: We believe that this siloxane readily covers the surface of F particles, and its interaction with F particles is highly efficient. That is, we believe that this siloxane highly adheres to F particles, thus selectively enhancing the dispersion stability of F particles in this dispersion and suppressing the decline in liquid properties. We further believe that the synergistic effect of hydrophobic silica and this siloxane improves the dispersion stability of F particles while inhibiting foaming in the liquid, thereby improving the workability of this dispersion in mixing and coating, and improving the surface smoothness of the resulting coating and other shaped products.

[0015] The F polymer used in this invention may be hot-meltable or non-hot-meltable, but preferably at least a portion of it is hot-meltable. Hot-meltable polymers are as described above, while non-hot-meltable polymers refer to polymers that do not have a melt flow rate of 1 to 1000 g / 10 minutes under a load of 49 N.

[0016] When polymer F is thermomeltable, its melting temperature is preferably above 200°C, more preferably above 260°C. When polymer F is a thermomeltable polymer, its melting temperature is preferably below 325°C, more preferably below 320°C. At this temperature, F particles readily interact with the siloxane, resulting in excellent dispersion stability and operability of the dispersion.

[0017] The glass transition point of polymer F is preferably 50°C or higher, more preferably 75°C or higher. The glass transition point of polymer F is preferably 150°C or lower, more preferably 125°C or lower. The fluorine content of polymer F is preferably 70% by mass or higher, more preferably 72-76% by mass. The surface tension of polymer F is preferably 16-26 mN / m. Furthermore, the surface tension of polymer F can be measured by carrying droplets of a wetting index reagent (manufactured by Wako Pure Chemical Industries, Ltd.) on a plate made of polymer F. Polymer F with high fluorine content has excellent electrical and physical properties. On the other hand, its surface tension is low and its adhesion is easily reduced. However, according to the present invention, by means of the above-mentioned mechanism, this dispersion with excellent dispersion stability and operability can be easily obtained.

[0018] The polymer F is preferably: polytetrafluoroethylene (hereinafter also referred to as "PTFE"), a polymer containing TFE units and ethylene units, a polymer containing TFE units and propylene units, a polymer containing units mainly composed of TFE units and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE units") (hereinafter also referred to as "PFA"), a polymer containing TFE units and hexafluoropropylene units (hereinafter also referred to as "FEP"), preferably PFA and FEP, and even more preferably PFA. These polymers may further contain units mainly composed of other comonomers. PAVE is preferably CF2=CFOCF3, CF2=CFOCF2CF3 and CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), preferably PPVE.

[0019] From the viewpoint of improving adhesion, the heat-melting F polymer preferably has oxygen-containing polar groups, more preferably hydroxyl-containing groups or carbonyl-containing groups, and even more preferably carbonyl-containing groups. The hydroxyl-containing groups are preferably alcohol-containing hydroxyl groups, preferably -CF2CH2OH and -C(CF3)2OH. The carbonyl-containing groups are preferably carboxyl groups, alkoxycarbonyl groups, amide groups, isocyanate groups, carbamate groups (-OC(O)NH2), anhydride residues (-C(O)OC(O)-), amide residues (-C(O)NHC(O)-, etc.), and carbonate groups (-OC(O)O-), preferably anhydride residues. When the F polymer has oxygen-containing polar groups, the number of oxygen-containing polar groups in the F polymer is preferably 10 to 5000 per 1×106 main chain carbons, preferably 100 to 3000. Furthermore, the number of oxygen-containing polar groups in polymer F can be quantified by the composition of the polymer or by the method described in International Publication No. 2020 / 145133.

[0020] The oxygen-containing polar group can be included in the monomer-based unit of the F polymer, or it can be included in the terminal group of the F polymer backbone, preferably the former. Examples of the latter include: F polymers having oxygen-containing polar groups in the form of terminal groups derived from polymerization initiators, chain transfer agents, etc.; and F polymers obtained by plasma treatment or ionization radiation treatment of F polymerization. The monomers having carbonyl groups are preferably itaconic anhydride, citraconic anhydride, and 5-norcamphene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), preferably NAH. The F polymer is preferably a polymer containing TFE units and PAVE units and having carbonyl groups, and more preferably a polymer that contains TFE units, PAVE units, and units mainly composed of monomers having carbonyl groups, and these units are contained in 90-99 mol%, 0.99-9.97 mol%, and 0.01-3 mol in sequence with respect to all units. Specific examples of this polymer F include the polymer described in International Publication No. 2018 / 16644.

[0021] The D50 of the F particles in this invention is preferably 0.1 μm or more, more preferably greater than 0.3 μm, and even more preferably 1 μm or more. The D50 of the F particles is preferably 25 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. The specific surface area of ​​the F particles is preferably 1~25 m² / g.

[0022] This dispersion may also contain two or more types of F particles. When containing two types of F particles, the F particles are preferably hot-melt F polymer particles and non-hot-melt F polymer particles, more preferably hot-melt F polymer particles containing TFE units and PAVE units and having carbonyl groups, and non-hot-melt PTFE particles. In this case, the dispersion stability and workability of this dispersion are easily excellent, and the electrical properties of the molded articles formed by this dispersion are easily excellent. The proportion of hot-melt F polymer particles in the total amount of hot-melt F polymer particles and non-hot-melt F polymer particles is preferably 50% by mass or less, more preferably 25% by mass or less. Furthermore, the aforementioned proportion is preferably 0.1% by mass or more, more preferably 1% by mass or more.

[0023] Furthermore, the D50 of the hot-melt F polymer particles should preferably be 1~4 μm, and the D50 of the non-hot-melt F polymer particles should preferably be 0.1~1 μm. F particles are particles containing F polymers, and preferably particles composed of F polymers. F particles may also contain resins or inorganic compounds other than F polymers, and may form a core-shell structure with the F polymer as the core and a resin or inorganic compound other than F polymer as the shell, or a core-shell structure with the F polymer as the shell and a resin or inorganic compound other than F polymer as the core. Examples of resins other than F polymers include aromatic polyesters, polyamide-imide, polyamide, and maleimide. Examples of inorganic compounds include silicon dioxide and boron nitride. The content of F particles in this dispersion should preferably be 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more. The content of F particles should preferably be below 60% by mass, and more preferably below 40% by mass.

[0024] This siloxane is an organopolysiloxane having dimethylsiloxane as a structural unit. It may have dimethylpolysiloxane units (-(CH3)2SiO2 / 2-) in the main chain, dimethylpolysiloxane units in the side chains, or dimethylsiloxane units in both the main chain and side chains. Preferably, this siloxane is a linear polymer having dimethylpolysiloxane units in the main chain. From the viewpoint of dispersion stability, this siloxane is preferably a polyoxyalkylene-modified polydimethylsiloxane. Examples of polyoxyalkylene-modified polydimethylsiloxanes include: polyoxyalkylene-modified polydimethylsiloxanes containing dimethylsiloxane units in the main chain and having oxyalkylene groups in the side chains; or polyoxyalkylene-modified polydimethylsiloxanes containing dimethylsiloxane units in the main chain and having oxyalkylene groups at the ends of the main chain.

[0025] The polyoxyalkylene-modified polydimethylsiloxane of the former preferably contains a diorganosiloxane unit of formula -(R1)(R2)SiO2 / 2- in the non-terminal portion of the main chain. The polyoxyalkylene-modified polydimethylsiloxane of the latter preferably contains a triorganosiloxane terminal group of formula (R1)2(R2)SiO2 / 2- in the terminal portion of the main chain. In the formula, R1 represents an alkyl group, preferably methyl. In the formula, R2 represents a group having a polyoxyalkylene group, preferably a group of formula -X2-O-(Y2)n-Z2 (in the formula, X2 represents an alkylene group, Y2 represents a polyoxyalkylene group, Z2 represents a hydrogen atom, alkyl or acetyl group, and n represents an integer from 2 to 100). Examples of X2 include: ethylene, propylene, and butylene. Examples of Y2 include: ethylene and propylene. Examples of alkyl or acetylated groups in Z2 include methyl and acetylated groups.

[0026] Furthermore, the polyoxyalkylene-modified dimethylsiloxane may contain polyoxyalkylene groups formed from two or more types of oxyalkylene groups. In the latter case, different types of oxyalkylene groups may be linked into random shapes or linked into blocks. The degree of polymerization of the oxyalkylene groups in the polyoxyalkylene-modified polydimethylsiloxane, i.e., the number of repeating units of the oxyalkylene groups, is preferably 2 or more. The degree of polymerization is preferably 100 or less, more preferably 50 or less, and even more preferably 20 or less. This siloxane is preferably formulated using both hydrophilic polydimethylsiloxane (hereinafter also referred to as "hydrophilic siloxane") and hydrophobic polydimethylsiloxane (hereinafter also referred to as "hydrophobic siloxane").

[0027] Hydrophilic silicates refer to silicates that are inherently hydrophilic. Here, inherently hydrophilic means that even if some of the functional groups contain hydrophobic groups, the silicate compound can still exhibit hydrophilicity. Hydrophilic silicates preferably have polyoxyethylene ethyl groups. In this case, the dispersion stability and operability of the dispersion are easily excellent. Examples of hydrophilic silicates include the aforementioned polyoxyethylene alkyl-modified polydimethylsiloxane, and examples of hydrophilic silicates include, for instance, polyoxyethylene alkyl-modified polydimethylsiloxane having the structure of formula (I) or (II) below. R12R3SiO-((CH3)2SiO)x-(R1R2SiO)y)-SiR12R3(I) However, in formula (I), R1 and R3 are each alkyl groups having 1 to 18 carbon atoms, R2 is an alkyl group represented by the formula -R4-O(CH2CH2O)a-[CH2(CH3)CHO]b-R5, x is an integer from 5 to 150, and y is an integer from 1 to 15. R4 is an alkyl group having 2 to 6 carbon atoms, and R5 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an acetyl group, or an isocyanate group. a is an integer greater than or equal to 1, b is an integer greater than or equal to 0, the sum of a and b is 3 to 80, and when b is not 0, the value of a divided by b is in the range of 0.25 to 4. R1 and R3 are preferably methyl groups, and R3 may also be an alkyl group other than methyl groups depending on the circumstances. R62R7SiO-((CH3)2SiO)n-SiR62R7(II) In formula (II), R6 is an alkyl group having 1 to 18 carbon atoms, R7 is a group represented by the formula -R8-O(CH2CH2O)c-R9, and c is an integer from 20 to 100. R8 is an alkyl group having 2 to 6 carbon atoms, and R9 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an acetyl group, or an isocyanate group. R6 is preferably methyl.

[0028] Hydrophobic siloxanes refer to siloxanes that are inherently hydrophobic. Here, "inherently hydrophobic" means that even if some of the functional groups contain hydrophilic groups, the siloxane compound should still exhibit hydrophobicity. The viscosity of the hydrophobic siloxane at 25°C, measured using an Ostwald viscometer, should preferably be 10~100,000 mm² / s, more preferably 50~10,000 mm² / s, from the viewpoint of defoaming and operability.

[0029] This silica can be either wet silica or dry silica. Examples of this silica include precipitated silica, silica dry gel, and fumed silica, specifically including commercially available products such as Nipsil (manufactured by Tosoh Silica), SYLYSIA (manufactured by Fuji Silysia Chemical), and AEROSIL (manufactured by NIPPON AEROSIL).

[0030] The methanol wettability of this silica is preferably 30-75, and more preferably 40-75. Methanol wettability refers to the lower limit of the methanol concentration (volume %) of the aqueous methanol solution used to form a dispersion when 5 mL of methanol-water solution and 0.2 g of hydrophobic silica are added to a 10 mL test tube, the tube is inverted 20 times, and allowed to stand for 2 minutes. Furthermore, methanol wettability is sometimes also referred to as the M value. This silica with this methanol wettability achieves a balance between dispersion and precipitation or floating states in the liquid. In addition to the synergistic effect with the silica alkane, it easily improves the bubble-breaking effect, thus enhancing the defoaming properties and other liquid properties of the dispersion.

[0031] The primary particle size of this silica is preferably 0.001~2.0 μm, more preferably 0.01~1.0 μm. The specific surface area of ​​this silica, as determined by the BET method, is preferably 100~700 m² / g, more preferably 100~500 m² / g. When at least one of the primary particle size and specific surface area is within the above range, the silica achieves a balance between its dispersion state and its sedimentation or floating state in the liquid. Besides having a synergistic effect with the silica alkane, it easily enhances its bubble-breaking effect, thus improving the defoaming properties and other liquid properties of the dispersion.

[0032] This silica can also be surface treated. Surface treatment can be performed using mixing and dispersing devices such as Henschel mixers, Loedige mixers, and high speeders, and can be performed by adding the raw silica powder to the aforementioned device, and spraying an organopolysiloxane before or during stirring. Heating or adding alkaline catalysts such as ammonia water can also be performed as needed. In this case, it is preferable to perform the treatment at a temperature from room temperature to 100°C, preferably at a temperature of 50 to 80°C, for 10 to 120 minutes, preferably for 15 to 60 minutes.

[0033] In addition, the amount of surface treatment agent such as basic polysiloxane relative to the silica may vary depending on the specific surface area of ​​the silica. However, when the specific surface area of ​​the silica is 100 to 700 m2 / g as shown by BET specific surface area, it is preferably 1 to 50 parts by mass relative to 100 parts by mass of the silica, and more preferably 5 to 30 parts by mass.

[0034] This dispersion preferably contains 11 parts by mass or less of the siloxane and 0.5 parts by mass or less of the silicon dioxide per 100 parts by mass of F particles. This dispersion may contain more than 0 parts by mass of the siloxane and silicon dioxide per 100 parts by mass of F particles, but from an effectiveness point of view, it is preferable to contain 0.1 parts by mass or less of the siloxane and 0.01 parts by mass or more of the silicon dioxide. When this dispersion is used in conjunction with the aforementioned hydrophilic and hydrophobic siloxanes, this dispersion preferably contains 10 parts by mass or less of the hydrophilic siloxane, 1 part by mass or less of the hydrophobic siloxane, and 0.5 parts by mass or less of the silicon dioxide per 100 parts by mass of F particles. When this dispersion is used in conjunction with the aforementioned hydrophilic and hydrophobic silicates, the dispersion shall preferably contain at least 0.1 parts by mass of hydrophilic silicate, at least 0.1 parts by mass of hydrophobic silicate, and at least 0.01 parts by mass of silica per 100 parts by mass of F particles.

[0035] In addition to the aforementioned siloxane and silicon dioxide, this dispersion may also contain polyether compounds. In this case, the polyether compound interacts with the F particles and has an antifoaming effect, thus easily improving the dispersion stability and workability of this dispersion. The polyether compound refers to the polyoxyalkylene compound shown in the following formula (III). R10O-(R11O)z-R10(III) However, in the above formula (III), R10 is a hydrogen atom or a monovalent organic group. The two R10s may be the same or different. z is an integer from 2 to 150. Examples of monovalent organic groups include alkyl groups such as methyl, ethyl, propyl, and butyl; alkenyl groups such as vinyl and allyl; and monovalent organic groups with 1 to 20 carbon atoms, preferably 1 to 18, such as acetyl or stearyl. R11 is ethyl or propyl. The multiple R11s may also be two or more different groups.

[0036] The weight-average molecular weight of the polyether compound, as determined by GPC, is preferably 500 to 5,000, and more preferably 1,000 to 4,000, from the viewpoint of dispersion stability and operability during application. When this dispersion contains the aforementioned polyether compound, from the viewpoint of dispersion stability, the dispersion preferably contains no more than 10 parts by mass of the siloxane, no more than 0.5 parts by mass of the silicon dioxide, and no more than 1 part by mass of the aforementioned polyether compound per 100 parts by mass of F particles. When this dispersion contains the aforementioned polyether compound, the dispersion preferably contains more than 0.1 parts by mass of the siloxane, more than 0.01 parts by mass of the silicon dioxide, and more than 0.1 parts by mass of the aforementioned polyether compound per 100 parts by mass of F particles. When the aforementioned polyether compound is incorporated, the siloxane is preferably the aforementioned hydrophilic siloxane.

[0037] This dispersion comprises the aforementioned F particles, the siloxane, the silicon dioxide, and water. The water content in this dispersion is preferably 40% by mass or more, more preferably 60% by mass or more. The water content is preferably 90% by mass or less, more preferably 80% by mass or less. This dispersion may also further contain a water-soluble liquid compound as a dispersion medium. Examples of water-soluble liquid compounds include water-soluble alcohols and water-soluble amides.

[0038] The viscosity of this dispersion is preferably 10 mPa·s or higher, more preferably 100 mPa·s or higher. The viscosity of this composition is preferably 10000 mPa·s or lower, more preferably 3000 mPa·s or lower. The viscosity of the dispersion was measured using a Type B viscometer at 25°C and 30 rpm. The measurement was repeated three times, and the average of the three measurements was taken.

[0039] The thixotropic ratio of this dispersion should be 1.0 to 3.0. The thixotropic ratio of the dispersion is calculated by dividing the viscosity η1 measured at 30 rpm by the viscosity η2 measured at 60 rpm. The viscosity of each component is measured three times, and the average of the three measurements is calculated.

[0040] The pH of this dispersion should preferably be greater than 7, and more preferably 8-10. At this pH, the siloxane is difficult to decompose, and the long-term storage properties of this dispersion are excellent. To adjust the pH, this dispersion may further contain a pH adjuster or a pH buffer. Examples of pH adjusters include amines, ammonia, and citric acid. Examples of pH buffers include tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium bicarbonate, ammonium carbonate, and ammonium acetate.

[0041] This dispersion may also contain a nonionic surfactant. Preferably, the nonionic surfactant is a glycol-based surfactant, an acetylene-based surfactant, a polysiloxane-based surfactant, or a fluorinated surfactant, with a polysiloxane-based surfactant being more preferred. Two or more nonionic surfactants may also be used. When using two nonionic surfactants, the nonionic surfactant is preferably a combination of a polysiloxane-based surfactant and a glycol-based surfactant.

[0042] Specific examples of nonionic surfactants include: the "Ftergent" series (manufactured by NEOS), the "Surflon" series (manufactured by AGC SEIMI CHEMICAL), the "Megafac" series (manufactured by DIC), the "UNIDYNE" series (manufactured by Daikin Industries), "BYK-347", "BYK-349", "BYK-378", "BYK-3451", "BYK-3455", "BYK-3456" (manufactured by BIGCHEMI・JAPAN), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.), and the "Tergitol" series (manufactured by Dow Chemical Company, "Tergitol TMN-100X", etc.). When this dispersion contains a nonionic surfactant, the content of the nonionic surfactant in this dispersion should preferably be 1 to 15% by mass.

[0043] This dispersion may further include a resin different from polymer F. The resin other than polymer F may be thermosetting or thermoplastic. The resin other than polymer F may be soluble in this dispersion or dispersed in this dispersion. The resin other than polymer F may also be included in this dispersion in the form of its precursor. Examples of resins other than polymer F include: polyester resins (such as liquid crystal aromatic polyesters), amide resins, epoxy resins, maleimide resins, urethane resins, polyphenylene ether resins, polyphenylene oxide resins, polyphenylene sulfide resins, and fluoropolymers other than polymer F.

[0044] The resin, other than the F polymer, is preferably an aromatic polymer or a fluoropolymer other than the F polymer. Examples of aromatic polymers include: aromatic polyimides, polyamides, or their salts, i.e., aromatic polyimide precursors, aromatic polyamide-imides, aromatic polyamide-imide precursors, aromatic polyether-imides, and aromatic polyether-imide precursors. The aromatic polymer is preferably water-soluble, and more preferably a water-soluble aromatic polyimide precursor or a water-soluble polyamide-imide or its precursor.

[0045] Examples of water-soluble aromatic polyamide precursors include polyamide acid and its salts obtained by polymerizing tetracarboxylic dianhydride with a diamine. Examples of water-soluble aromatic polyamide imides or their precursors include polyamide imides or their precursors obtained by reacting at least one of a diisocyanate or a diamine with a tricarboxylic acid anhydride.

[0046] Examples of tetracarboxylic dianhydrides include phenyltetracarboxylic anhydride and biphenyltetracarboxylic anhydride. Examples of diamines include phenylenediamine, 3,3'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl ether. Examples of diisocyanates include 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, and 3,3'-diphenylmethane diisocyanate.

[0047] The number average molecular weight (Mn) of the aromatic polymer should preferably be 5000~50000. The acid value of the aromatic polymer should preferably be 20~100 mg / KOH. The acid value of the aromatic polymer can be determined by the following method: titrating a mixed solution of 0.5 g of aromatic polymer, 0.15 g of 1,4-diazabicyclo[2.2.2]octane, 60 g of N-methyl-2-pyrrolidone and 1 mL of deionized water using a potentiometric titration apparatus, wherein the potentiometric titration apparatus uses an ethanolic potassium hydroxide solution of 0.05 moles / L. In addition, when the aromatic polymer has an anhydride group, the acid value at which the anhydride group is opened is taken as the acid value of the aromatic polymer.

[0048] When this dispersion contains aromatic polymers, the content of aromatic polymers should preferably be 0.1% by mass or more, more preferably 0.3% by mass or more. The content of aromatic polymers should preferably be 30% by mass or less, more preferably 10% by mass or less.

[0049] Examples of fluoropolymers other than F polymers include polychlorotrifluoroethylene, polyvinyl fluoride, and polyvinyl fluoride. When this dispersion contains fluoropolymers other than F polymers, the content of the fluoropolymers other than F polymers is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. The content of aromatic polymers is preferably 30% by mass or less, more preferably 10% by mass or less.

[0050] This dispersion may further contain inorganic fillers other than hydrophobic silica. Two or more types of inorganic fillers may be used. The inorganic filler should preferably be spherical, needle-like, fibrous, or plate-like, preferably spherical, scaly, or layered, and more preferably spherical or scaly. Spherical inorganic fillers should preferably be approximately true spherical. Approximately true spherical means that when observed by a scanning electron microscope (SEM), the proportion of inorganic fillers with a minor axis to major axis ratio of 0.7 or higher is 95% or higher. The aspect ratio of non-spherical inorganic fillers should preferably be 2 or higher, preferably 5 or higher. The aspect ratio should preferably be 10000 or lower.

[0051] The inorganic filler is preferably carbon filler, inorganic nitride filler, or inorganic oxide filler, more preferably carbon fiber filler, boron nitride filler, aluminum nitride filler, beryllium filler, silica filler other than hydrophobic silica, silash filler, talc filler, cerium oxide filler, alumina filler, magnesium oxide filler, zinc oxide filler, or titanium oxide filler, and even more preferably boron nitride filler and silica filler other than hydrophobic silica. Furthermore, the silica filler other than hydrophobic silica is a hydrophilic silica filler, preferably untreated or surface-treated with a hydrophilic surface treatment agent. The D50 of the inorganic filler is preferably less than 20 μm, more preferably less than 10 μm. The D50 is preferably greater than 0.01 μm, more preferably greater than 0.1 μm. The specific surface area of ​​the inorganic filler is preferably 1~20 m² / g.

[0052] The surface of the inorganic filler can also be surface-treated with a silane coupling agent. The silane coupling agent is preferably a silane coupling agent with the following functional groups: 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidylpropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanate propyltrimethoxysilane, etc.

[0053] Specific examples of silica fillers other than hydrophobic silica include the "ADMAFINE" series (manufactured by Admatechs), the "SFP" series (manufactured by Denka), and the "E-SPHERES" series (manufactured by Taiheiyo Cement). Specific examples of zinc oxide fillers include the "FINEX" series (manufactured by Sakai Chemical Industry Co., Ltd.). Specific examples of titanium oxide fillers include the "TIPAQUE" series (manufactured by Ishihara Sangyo Co., Ltd.) and the "JMT" series (manufactured by TAYCA). Specific examples of talc fillers include the "SG" series (manufactured by NIPPON TALC). Specific examples of steatite fillers include the "BST" series (manufactured by NIPPON TALC). Specific examples of boron nitride fillers include the "UHP" series (manufactured by Showa Denko) and the "GP" and "HGP" grades of the "Denka Boron Nitride" series (manufactured by Denka). When the dispersion contains inorganic fillers other than hydrophobic silicon dioxide, the content of such inorganic fillers in the dispersion should preferably be 10-40% by mass.

[0054] This dispersion may further contain a polyol other than the aforementioned polyether compound. The polyol has two or more alcoholic hydroxyl groups and is a compound other than the polyoxyalkylene compound shown in formula (III), hereinafter referred to as a polyol. Preferably, the polyol is an aliphatic polyol containing two or three alcoholic hydroxyl groups and without nitrogen atoms, with a boiling point of 100°C or higher. The boiling point of the polyol is preferably 150°C or higher, preferably 200°C or higher. The boiling point is preferably 340°C or lower. Furthermore, the polyol is preferably miscible with water.

[0055] Examples of polyols include: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-buten-1,4-diol, glycerol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, and 1,2,6-hexanetriol. Glycerol is preferred as the polyol. In this case, the dispersibility of F particles in the dispersion is further improved, and the dispersion stability and operability of the dispersion are excellent. One type of polyol can be used alone, or two or more can be used in combination.

[0056] When this dispersion contains polyol, the mass ratio of polyol to water should preferably be 0.2 or more, and more preferably 0.5 or more. This mass ratio should preferably be 10 or less, and more preferably 5 or less. When the mass ratio is within this range, the anti-agglomeration effect and the rheological adjustment effect of the polyol will be well balanced, resulting in excellent dispersion stability of this dispersion.

[0057] In addition to the aforementioned components, this dispersion may also contain, as required, additives such as: thixotropic agents, viscosity modifiers, defoamers, 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, and various fillers.

[0058] This dispersion is preferably manufactured by the following methods: adding F particles, the siloxane, and the silica, along with other components such as the aforementioned polyether compound, inorganic filler, resin different from the F polymer, and additives as needed, to water and mixing them; adding F particles and other components sequentially to water and mixing them; pre-mixing F particles with water and other components with water separately before mixing them; mixing F particles with other components and then mixing them with water. These mixing methods can be carried out in batches or continuously.

[0059] As mixing devices, examples include: Henschel mixers, pressure kneaders, Bamboo mixers, and planetary mixers, which are mixing devices with blades; ball mills, grinding mills, basket mills, sand mills, sand grinders, dyno mills, dispermats, SC mills, spike mills, or stirred mills, which are pulverizing devices with media; and microfluidic homogenizers, nanomizers, high-pressure homogenizers, ultrasonic homogenizers, dissolvers, dispersants, high-speed impellers, self-rotating and revolution-rotating mixers, or thin-film rotary mixers, which are dispersion devices with other mechanisms.

[0060] A suitable manufacturing method for this dispersion is as follows: F particles are pre-mixed with a portion of water to obtain a mixture, and then the aforementioned mixture is added to the remaining water to obtain a dispersion. When this dispersion further includes other components such as polyether compounds, inorganic fillers, and other resins, these other components may be mixed during mixing or added. The mixture obtained from mixing may be a paste or a wet powder. A paste refers to a paste with a viscosity of 1000 to 100000 mPa·s. A wet powder refers to a wet powder with a viscosity of 10000 to 100000 Pa·s as measured by a capillary rheometer. Furthermore, the viscosity measured by the capillary rheometer refers to the value measured using a capillary with a length of 10 mm and a radius of 1 mm, with the furnace diameter set to 9.55 mm, the load cell capacity set to 2 t, the temperature set to 25 °C, and the shear rate set to 1 s⁻¹.

[0061] Mixing during the mixing process should preferably be carried out using a planetary mixer. A planetary mixer is a mixing device with two-axis mixing blades that rotate on their own axis and revolve around the sun. Mixing during the addition process should preferably be carried out using a thin-film rotary high-speed mixer. A thin-film rotary high-speed mixer is a mixing device that spreads F particles and liquid dispersion media into a thin film on the inner wall of a cylindrical mixing tank and rotates it, mixing them while centrifugal force is applied.

[0062] This method involves forming a layer of the dispersion (hereinafter also referred to as "wet film layer") on the surface of a substrate, then heating the dispersion layer to remove water and forming a layer containing polymer F (hereinafter also referred to as "dry film layer") on the surface of the substrate, thereby manufacturing the laminate. After forming the dry film layer, if the dry film layer is further heated to calcine the polymer F, a laminate having a substrate layer and a calcined layer containing polymer F located on the surface of the substrate layer (hereinafter also referred to as "F layer") can be obtained. The formation of the F layer can be performed consecutively with the formation of the dry film layer, or it can be performed using a different step than the formation of the dry film layer.

[0063] Examples of substrates include: metal substrates such as metal foils made of copper, nickel, aluminum, titanium, and alloys thereof; heat-resistant resin films such as heat-resistant resin films made of polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryl ether ketone, polyamide-imide, liquid crystal polyester, and F polymer; prepreg substrates, which are precursors of fiber-reinforced resin substrates; ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates. Among these substrates, copper foil and polyimide films are particularly suitable, and low-roughness copper foil is also preferred. Examples of substrate shapes include planar, curved, and uneven shapes. Furthermore, the substrate shape can also be any of foil, plate, film, or fibrous.

[0064] The average roughness of ten points on the substrate surface should preferably be 0.01~0.05μm. The substrate surface can be surface treated with a silane coupling agent or plasma treatment. The silane coupling agent should preferably be one of the following functional groups: 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidylpropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanate propyltrimethoxysilane, etc.

[0065] A method for forming a wet film layer on the surface of a substrate using this dispersion may include, for example, a coating method. Coating methods may include coating, droplet spraying, and dipping, and are preferably roller coating, doctor blade coating, bar coating, mold coating, or spraying.

[0066] When removing water from the wet film layer by heating to form a dry film layer, the heating should preferably be performed at 100~200°C for 0.1~30 minutes. It is not necessary to completely remove the water during this heating; removal is sufficient until the layer formed by the coating of the F particles can maintain the film's integrity. Furthermore, air can be blown during heating to promote water removal through air drying. Moreover, when a water-soluble liquid compound other than water is further included as the liquid dispersion medium of this dispersion, the water-soluble liquid compound other than water should also be removed along with the water by the aforementioned heating.

[0067] The F layer can be formed by firing the F polymer through heating the dry film layer. Alternatively, the temperature can be further increased during the heating stage of forming the aforementioned dry film layer to fire the F polymer. The heating for firing the F polymer should preferably be performed at 360~400°C for 0.1~30 minutes. When the F polymer is a thermoplastic F polymer, the heating for firing the F polymer should preferably be performed above the melting temperature of the F polymer.

[0068] In the heating for forming the dry film layer and the heating for forming the F layer, the respective heating devices can be an oven or a ventilated drying furnace. The heat source in the device can be a contact heat source such as hot air or a hot plate, or a non-contact heat source such as infrared radiation. The respective heating can be carried out under normal pressure or under reduced pressure.

[0069] The gas environment for each heating step can be any of the following: an air environment; an inactive gas environment such as helium, neon, argon, or nitrogen. The F layer is formed by contacting the dispersion with the substrate and then heating it. These steps can be performed one at a time or repeated two or more times. For example, the dispersion can be coated onto the surface of the substrate and heated to form a dry film layer, followed by the formation of the F layer, and then the dispersion can be coated onto the surface of the aforementioned F layer and heated to form a second F layer. Alternatively, during the stage of coating the dispersion onto the surface of the substrate and heating to form a dry film layer, the dispersion can be further coated onto its surface and heated to form the F layer.

[0070] This dispersion may contact only one surface of the substrate or both surfaces of the substrate. In the former case, the resulting laminate has a substrate layer and an F layer located on one side of the substrate layer; in the latter case, the resulting laminate has a substrate layer and F layers located on both sides of the substrate layer. Suitable examples of the laminate include: a metal-coated laminate having a metal foil and an F layer located on at least one surface of the metal foil; and a multilayer film having a polyimide film and F layers located on both surfaces of the polyimide film. The thickness of the F layer is preferably 10 μm or more, more preferably 10 to 200 μm, and even more preferably 10 to 50 μm. The peel strength between the F layer and the substrate layer is preferably 10 to 100 N / cm. A film containing the F polymer can also be obtained by further removing the substrate layer from the laminate.

[0071] This multilayer exhibits excellent electrical properties, making it suitable as a printed circuit board material. Specifically, it can be used to manufacture printed circuit boards in the form of flexible metal-clad laminates and rigid metal-clad laminates. It is particularly suitable for manufacturing flexible printed circuit boards in the form of flexible metal-clad laminates. During the manufacture of this printed circuit board, an interlayer insulating film can be formed on the transmission circuit, a solder resist can be deposited on the transmission circuit, and a capping film can be deposited on the transmission circuit. These interlayer insulating films, solder resists, and capping films can also be formed using this dispersion.

[0072] This laminate is useful for: antenna components, printed circuit boards, aircraft components, automotive components, sporting goods, food industry products, heat dissipation components, coatings, cosmetics, etc. In printed circuit boards, it can prevent temperature rise in printed circuit boards with high-density mounting of electronic components, and can also be used as a new printed circuit board material to replace conventional glass epoxy boards. Specifically, it is useful for: wire coating materials for aircraft wires, enameled wire coating materials for motors used in electric vehicles, electrical insulating tapes, oil drilling insulating tapes, printed circuit board materials, precision filter membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.; electrode adhesives for lithium secondary batteries, fuel cells, etc.; coatings for printing rollers, furniture, automotive dashboards, home appliances, etc.; heavy-duty bearings, sliding shafts, valves, bearings, bushings, seals, thrust bearings, etc. Sliding components such as gaskets, wear rings, pistons, slide switches, gears, cams, belt conveyors, and conveyor belts for handling food; wear pads, wear strips, tube lights, test sockets, wafer guides, wear parts for centrifugal pumps, pumps for supplying hydrocarbons, pharmaceuticals, and water, tools such as shovels, files, awls, and saws; boilers, funnels, pipes, ovens, baking molds, chutes, dies, toilets, container coverings, power units, transistors, thyristors, rectifiers, transformers, power MOSFETs, CPUs, cooling fans, metal heat sinks, windmills, wind power generation equipment, and aircraft rotors. More specifically, it is useful as: computer and monitor frames, electronic equipment materials, automotive interior and exterior parts, sealing materials for processing machines that undergo heat treatment in low-oxygen environments, vacuum ovens, plasma processing equipment, weld spatter, and heat dissipation components within processing units of various dry etching equipment.

[0073] Furthermore, this dispersion can also be used for the following applications: impregnating coils used as insulating layers for printed circuit boards, thermal interface materials, power module substrates, motors, and other power devices, and drying them to form a thermally conductive and heat-resistant coating; further processing ceramic and metal parts in automotive engines; imparting corrosion resistance to heat exchangers, their fans, or pipes; and coating the inside and outside of glass containers. It is particularly suitable for imparting impact-resistant coatings. Examples of glass containers include vials, syringes, syringes with needles, cartridge syringes, and ampoules.

[0074] Furthermore, this dispersion can be used as a capacitor for: secondary batteries such as lithium-ion batteries, primary batteries such as lithium batteries, free radical batteries, solar cells, especially pigment-sensitized solar cells, fuel cells, lithium-ion capacitors, hybrid capacitors, electric double-layer capacitors, etc.; various capacitors such as aluminum electrolytic capacitors and tantalum electrolytic capacitors; electrochemical devices with electrodes such as electrochromic elements, electrochemical conversion elements, and various electrochemical sensors; adhesive materials for electrodes, coating materials for separators, and coating materials for positive or negative electrodes.

[0075] Furthermore, when this dispersion contains conductive fillers, it can also be used in applications requiring conductivity, such as the field of printed electronics. Specifically, it can be used to manufacture electrically conductive components such as: printed circuit boards, sensor electrodes, displays, backplanes, RFID (Radio Frequency Identification), solar power generation, lighting, disposable electronic devices, automotive heaters, electromagnetic interference (EMI) shielding, and diaphragm switches. Furthermore, the sintered product obtained from this dispersion can be used as an adhesive in semiconductor components, high-density substrates, module parts, etc., to bond IC chips, resistors, capacitors, and other electronic components mounted on the substrate, or to bond circuit boards and heat sinks, or to bond LED chips to the substrate. Further, the aforementioned sintered product can also be used as a conductive bonding material between circuit wiring and electronic components during the mounting process (as an alternative to solder bonding). It can also be used as an adhesive for bonding ceramic and metal parts to each other in automotive engines. Furthermore, the above-mentioned fired products can also be used for the purposes described in International Publication No. 2016 / 017801, paragraph number

[0149] .

[0076] Although the manufacturing method of the dispersion and the laminate has been described above, the present invention is not limited to the configuration of the above embodiments. For example, in the configuration of the above embodiments, other arbitrary configurations may be added to the dispersion, or it may be replaced with any configuration that can perform the same function. Furthermore, in the manufacturing method of the laminate, other arbitrary steps may be added to the configuration of the above embodiments, or it may be replaced with any step that can produce the same effect.

[0077] The present invention will be described in detail below by way of examples, but the present invention is not limited thereto. 1. Preparation of each component [F particles] F particles 1: Particles constituting the following powder (D50: 1.7 μm), the powder system containing 97.9 mol% TFE units, 0.1 mol% NAH units and 2.0 mol% PPVE units, and a polymer (melting temperature: 300°C) with 1 × 106 carbon atoms per main chain F particles 2: Particles constituting the following powder (D50: 1.8 μm), the powder system containing 98.7 mol% TFE units and 1.3 mol% PPVE units, and a polymer (melting temperature: 305°C) without oxygen-containing polar groups.

[0078] [Silicone Compounds] Silicone 1: Hydrophilic polyoxyalkylene-modified polydimethylsiloxane (manufactured by BIGCHEMI JAPAN, "BYK-3450") having dimethylsiloxane units in the main chain and oxyethyl groups in the side chains. Silicone 2: Hydrophobic polydimethylsiloxane (viscosity at 25°C, measured by an Ostwald viscometer: 8000 mm² / s).

[0079] [Hydrophobic Silicon Dioxide] Silicon Dioxide 1: Hydrophobic silicon dioxide with a surface treated with dimethyl polysiloxane having hydroxyl groups at both ends (specific surface area: 300 m² / g, manufactured by NIPPON AEROSIL, "AEROSIL 300") Silicon Dioxide 2: Hydrophobic silicon dioxide with a surface treated trimethylsilyl group (primary particle size: 0.01 μm, specific surface area: 130 m² / g, methanol wettability: 70, manufactured by NIPPON AEROSIL, "RX200") Silicon Dioxide 3: Hydrophobic silicon dioxide with a surface treated alkylsilyl group (primary particle size: 0.01 μm, specific surface area: 150 m² / g, methanol wettability: 50, manufactured by NIPPON AEROSIL, "R805") Silicon dioxide 3: Surface-treated hydrophobic silicon dioxide with dimethylsilicon groups (primary particle size: 0.01 μm, specific surface area: 170 m2 / g, methanol wettability: 35, manufactured by NIPPON AEROSIL "R974")

[0080] [Polyether] Polyether 1: A ring-opening addition polymer of ethylene oxide and propylene oxide with 25 oxyethyl units and 35 oxypropyl units.

[0081] [Varnish of Aromatic Polyamide Imide] Varnish 1: Water-based varnish [polyurethane] containing aromatic polyamide imide precursor (PAI1) Polyurethane 1: Polyurethane tackifier (ADEKA Corporation "ADEKA NOL UH450VF")

[0082] 2. Preparation of the dispersion: Water and F particles 1 are added to a container containing zirconium dioxide spheres, followed by the addition of siloxane 1, siloxane 2, silicon dioxide 1, varnish 1, and polyurethane 1. The container is rotated to obtain dispersion 1, which contains 56.5 parts by mass of water, 40 parts by mass of F particles, 2 parts by mass of siloxane 1, 0.3 parts by mass of siloxane 2, 0.1 parts by mass of silicon dioxide 1, 0.1 parts by mass of PAI 1, and 0.8 parts by mass of polyurethane 1, and F particles 1 are dispersed therein. Dispersions 2 to 6 are prepared in the same manner as dispersion 1, except that the composition of the dispersion is changed as shown in Table 1.

[0083] [Table 1]

[0084] 3. Fabrication of the laminate: Dispersion 1 is coated onto the surface of a strip of copper foil with a thickness of 18 μm using a small-diameter gravure reverse coating method to form a wet film layer. Next, the copper foil with the wet film layer is passed through a drying oven at 110°C for 5 minutes to dry it by heating and obtain a dry film layer. Then, the dry film layer is heated at 380°C for 3 minutes in an oven under a nitrogen atmosphere. This produces laminate 1, which includes a copper foil and polymer 1 on the surface of the copper foil, and has a polymer layer with a thickness of 25 μm. Laminates 2 to 6 are manufactured in the same manner as laminate 1, except that dispersion 1 is changed to dispersions 2 to 6.

[0085] 4. Evaluation 4-1. Evaluation of Dispersion Stability Individual dispersions (18 mL) were added to a threaded tube (internal volume: 30 mL) and allowed to stand at 25°C for 14 days. After standing, the dispersion ratio was calculated by combining the overall height of the dispersion and the height of the sediment layer (dispersion layer) in the threaded tube using the following formula. Further confirmation of redispersibility when the threaded tube was manually shaken was then made, and the dispersion stability was evaluated according to the following criteria. [Evaluation Criteria] 〇: Dispersion ratio ≥ 60%, and easily redispersible △: Dispersion ratio < 60%, but easily redispersible ×: Dispersion ratio < 60%, and difficult to redispersible

[0086] 4-2. Evaluation of Coating and Film Properties: Visually observe whether there are cracks on the surface of the polymer layer of the resulting laminate when fabricating from individual dispersions, and evaluate the film-forming properties according to the following criteria. [Evaluation Criteria] ◎: No cracks observed ○: Fine cracks observed at the edges of the polymer layer △: Fine cracks observed throughout the polymer layer ×: Large cracks observed throughout the polymer layer

[0087] 4-3. Evaluation of the electrical properties of the laminate: Rectangular test pieces, 100 mm long and 50 mm wide, were cut from individual laminates. Copper foil was removed by etching with ferric chloride aqueous solution to obtain a single polymer layer. The dielectric loss tangent of the polymer layer was measured using the SPDR (Split Columnar Dielectric Resonance) method (measurement frequency: 10 GHz), and evaluated according to the following criteria. [Evaluation Criteria] 〇: Dielectric loss tangent less than 0.0020 △: Dielectric loss tangent greater than 0.0020 and less than 0.0025 ×: Dielectric loss tangent greater than 0.0025

[0088] 4-4. Evaluation of the peel strength of the laminate: A rectangular test piece (100 mm long and 10 mm wide) is cut from an individual laminate. The test piece is fixed at a position 50 mm from one end in the length direction. At a tensile speed of 50 mm / min, the polymer layer is peeled from the copper foil at a 90° angle from one end in the length direction. The maximum load applied at this time is taken as the peel strength, and the peel strength is evaluated according to the following criteria. [Evaluation Criteria] 〇: Peel strength greater than 12 N / cm △: Peel strength greater than 8 N / cm and less than 12 N / cm ×: Peel strength less than 8 N / cm These evaluation results are summarized and shown in Table 2.

[0089] [Table 2]

[0090] Except for replacing silicon dioxide 1 in the manufacture of dispersion 2 with silicon dioxide 2, silicon dioxide 3, or silicon dioxide 4, dispersion 21 containing silicon dioxide 2, dispersion 31 containing silicon dioxide 3, and dispersion 41 containing silicon dioxide 4 are obtained in the same manner. The dispersion stability of each dispersion is the same as that of dispersion 2, and dispersion 31 in particular has excellent dispersion stability. Furthermore, when boron nitride particles 25 parts by mass are sheared and stirred to 100 parts by mass of each dispersion, dispersion 21 and dispersion 31 have less foaming than dispersion 41, and dispersion 21 in particular also has excellent defoaming properties.

[0091] Furthermore, when using siloxane 2 and silicon dioxide 1 together, they are pre-mixed and used in the form of a polysiloxane oil compound. This can also be replaced by commercially available products such as BYK-017, BYK-1786, and BYK-1789 (all manufactured by BIGCHEMI JAPAN). When using polyether 1 and silicon dioxide 1 together, they are also pre-mixed and used in the form of a polysiloxane oil compound. This can also be replaced by commercially available products such as BYK-012 (manufactured by BIGCHEMI JAPAN).

[0092] As shown in the above results, the dispersion exhibits excellent dispersion stability, ease of application, and surface smoothness of the resulting coating. Furthermore, the laminate obtained from this dispersion fully possesses the electrical properties of the F polymer and exhibits excellent peel strength to the substrate. In addition, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-131924, filed on August 13, 2021, are incorporated herein by reference and are included as disclosure in this specification.

Claims

1. An aqueous dispersion comprising: particles containing a tetrafluoroethylene-based polymer, a polydimethylsiloxane compound, hydrophobic silica, and water, wherein the aforementioned tetrafluoroethylene-based polymer comprises units mainly composed of tetrafluoroethylene and units mainly composed of perfluoro(alkyl vinyl ether), and has a melting temperature of 200°C or higher and 320°C or lower, and the aforementioned hydrophobic silica has a methanol wetting value of 40 to 75.

2. The aqueous dispersion of claim 1, wherein at least a portion of the aforementioned polydimethylsiloxane compound is a hydrophilic polydimethylsiloxane having polyoxyethyl groups.

3. The aqueous dispersion of claim 1 or 2, comprising a hydrophilic polydimethylsiloxane having polyoxyethylated form and a hydrophobic polydimethylsiloxane with a viscosity of 10 to 100,000 mm² / s as the aforementioned polydimethylsiloxane compound.

4. The aqueous dispersion of claim 1 or 2, wherein the primary particle size of the aforementioned hydrophobic silica is 0.01~20μm.

5. The aqueous dispersion of claim 1 or 2, wherein the specific surface area of ​​the aforementioned hydrophobic silica is 100~700 m2 / g.

6. The aqueous dispersion of claim 1 or 2, wherein the content of the aforementioned tetrafluoroethylene-based polymer particles is 30% by mass or more.

7. The aqueous dispersion of claim 1 or 2, wherein, relative to 100 parts by mass of the aforementioned tetrafluoroethylene-based polymer particles, the aforementioned polydimethylsiloxane compound contains 11 parts by mass or less, and the aforementioned hydrophobic silica contains 0.5 parts by mass or less.

8. The aqueous dispersion of claim 1 or 2 further comprises a polyether compound.

9. The aqueous dispersion of claim 8, wherein the aforementioned polyether compound comprises 1 part by mass or less relative to 100 parts by mass of the aforementioned tetrafluoroethylene-containing polymer particles.

10. The aqueous dispersion of claim 1 or 2, wherein the aforementioned tetrafluoroethylene polymer is a polymer having an oxygen-containing polar group.

11. The aqueous dispersion of claim 1 or 2, comprising particles containing a thermally fusible tetrafluoroethylene polymer and particles containing a non-thermally fusible tetrafluoroethylene polymer as the aforementioned particles containing a tetrafluoroethylene polymer.

12. A method for manufacturing a laminate, comprising forming a layer of an aqueous dispersion as described in any one of claims 1 to 11 on the surface of a substrate, and then heating the aqueous dispersion layer to remove water and forming a layer containing a tetrafluoroethylene polymer on the surface of the substrate, thereby obtaining a laminate having the aforementioned tetrafluoroethylene polymer layer and the aforementioned substrate.

13. The manufacturing method of claim 12, wherein the aforementioned layer of a tetrafluoroethylene-based polymer formed by heating to remove water is fired.

14. The manufacturing method of claim 12 or 13, wherein the thickness of the aforementioned layer containing the tetrafluoroethylene polymer is 10 μm or more.