Water-based dispersion and method for manufacturing laminate

Abstract

The present application provides a water-based dispersion liquid, which is excellent in dispersion stability, workability at the time of mixing or coating, and surface smoothness of a resulting coating film, and a method for manufacturing a laminate obtained from the water-based dispersion liquid. The water-based dispersion liquid contains particles containing a tetrafluoroethylene-based polymer, a polydimethylsiloxane-based compound, hydrophobic silica, and water.

Description

Technical Field

[0001] This invention relates to aqueous dispersions and methods for manufacturing laminates obtained from said aqueous dispersions. More specifically, it relates to aqueous dispersions comprising tetrafluoroethylene-based polymers and methods for manufacturing laminates obtained from said aqueous dispersions. Background Technology

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

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

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-199902 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, aqueous dispersions containing tetrafluoroethylene polymer particles, which are used as liquid dispersion media, are prone to foaming and have poor operability when preparing the dispersion, mixing it with other components such as resin varnishes, or applying it. Furthermore, managing the pH value, viscosity, and other liquid properties of the dispersion is complex for long-term stable storage.

[0009] The inventors discovered that by adding polydimethylsiloxane compounds and hydrophobic silica, an aqueous dispersion with excellent dispersion stability, workability during mixing or coating, and surface smoothness of the resulting coating film can be obtained, thus completing the present invention.

[0010] The present invention provides an aqueous dispersion with excellent dispersion stability, operability during mixing or coating, and surface smoothness of the resulting coating film, and a method for manufacturing a laminate obtained from the aqueous dispersion.

[0011] Technical solutions adopted to solve technical problems

[0012] The present invention has the following technical content.

[0013] [1] An aqueous dispersion comprising particles containing a tetrafluoroethylene polymer, a polydimethylsiloxane compound, hydrophobic silica and water.

[0014] [2] The aqueous dispersion as described in [1], wherein at least a portion of the polydimethylsiloxane compound is a hydrophilic polydimethylsiloxane having polyoxyethylene.

[0015] [3] An aqueous dispersion as described in [1] or [2], wherein the polydimethylsiloxane compound comprises a hydrophilic polydimethylsiloxane having a polyoxyethylene content and a viscosity of 10 to 100,000 mm. 2 / s of hydrophobic polydimethylsiloxane.

[0016] [4] An aqueous dispersion as described in any one of [1] to [3], wherein the methanol wetting value of the hydrophobic silica is 30 to 75.

[0017] [5] An aqueous dispersion as described in any one of [1] to [4], wherein the primary particle size of the hydrophobic silica is 0.01 to 20 μm.

[0018] [6] An aqueous dispersion as described in any one of [1] to [5], wherein the specific surface area of ​​the hydrophobic silica is 100 to 700 m². 2 / g.

[0019] [7] The dispersion as described in any one of [1] to [6], wherein the content of the particles containing the tetrafluoroethylene polymer is 30% by mass or more.

[0020] [8] An aqueous dispersion as described in any one of [1] to [7], wherein the particles containing the tetrafluoroethylene-based polymer comprise no more than 11 parts by mass of the polydimethylsiloxane compound and no more than 0.5 parts by mass of the hydrophobic silica relative to 100 parts by mass.

[0021] [9] The aqueous dispersion of any one of [1] to [8] further comprises a polyether compound.

[0022]

[10] An aqueous dispersion as described in [9], wherein the polyether compound comprises less than 1 part by mass of the particles containing the tetrafluoroethylene polymer relative to 100 parts by mass.

[0023]

[11] An aqueous dispersion as described in any one of [1] to

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

[0024]

[12] An aqueous dispersion as described in any one of [1] to

[11] , wherein the particles containing the tetrafluoroethylene polymer comprise particles containing thermally fusible tetrafluoroethylene polymers and particles containing non-thermally fusible tetrafluoroethylene polymers.

[0025]

[13] A method for manufacturing a laminate having a layer containing a tetrafluoroethylene polymer and a substrate, the method comprising: forming a layer of an aqueous dispersion as described in any one of [1] to

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

[0026]

[14] The manufacturing method as described in

[13] , wherein the layer containing a tetrafluoroethylene polymer formed by heating to remove water is sintered.

[0027]

[15] The manufacturing method as described in

[13] or

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

[0028] Invention Effects

[0029] According to the present invention, an aqueous dispersion with excellent dispersion stability, operability when mixed or coated with other materials, and surface smoothness of the resulting coating film, and a method for manufacturing a laminate obtained from the aqueous dispersion, are provided. Detailed Implementation

[0030] The following terms have the following meanings.

[0031] "Tetrafluoroethylene polymers" are polymers containing tetrafluoroethylene (hereinafter also referred to as "TFE units") units, and are also abbreviated as "F polymers".

[0032] "Hot-melting tetrafluoroethylene polymers" refers to the aforementioned tetrafluoroethylene polymers, specifically those exhibiting melt flowability at temperatures reaching 1–1000 g / 10 minutes under a load of 49 N. They are also abbreviated below as "hot-melting F polymers".

[0033] The glass transition temperature (Tg) of a polymer is a value determined by analyzing polymers using the dynamic viscoelasticity assay (DMA).

[0034] "The melting temperature (melting point) of a polymer" refers to the temperature at which the maximum value of the polymer's melting peak is determined using differential scanning calorimetry (DSC).

[0035] "D50" is the average particle size of the particle aggregate, i.e., the cumulative 50% diameter of the powder volume, determined by laser diffraction scattering. Specifically, it is the particle size at the point where the cumulative volume reaches 50% by measuring the particle size distribution using laser diffraction scattering and calculating the cumulative curve with the total powder volume as 100%.

[0036] "D90" is the cumulative volumetric particle size of the powder, which is the cumulative 90% diameter of the powder's volumetric reference, calculated in the same way as "D50".

[0037] "Monomer-based unit" refers to a group of atoms based on one molecule of a monomer, formed through monomer polymerization. The unit can be formed directly through a polymerization reaction, or it can be formed by processing the polymer to transform a portion of the unit into a unit with a different structure. Hereinafter, monomer-a-based unit will also be abbreviated as "monomer a-unit".

[0038] 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.

[0039] 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 the F polymer and a substrate, wherein a layer of the dispersion is formed on the surface of a substrate, and then water is removed from the layer of the aqueous dispersion by heating to form a layer containing the F polymer on the surface of the substrate (hereinafter also referred to as "this laminate").

[0040] F-polymers are rigid polymers with extremely low affinity for other components. Therefore, aqueous dispersions containing F-particles, using water as the liquid dispersion medium, are prone to foaming. Furthermore, F-particles have low water wettability, resulting in poor workability during their own preparation, when mixed with other components such as resins and varnishes, or during coating.

[0041] This dispersion exhibits excellent foaming suppression, dispersion stability, workability, and long-term shelf life. The laminates formed from this dispersion possess excellent electrical properties and other physical properties based on the F polymer, as well as excellent surface smoothness.

[0042] The reasons are not yet clear, but the following are believed to be the causes.

[0043] It is believed that this siloxane readily coats the surface of F particles and enhances the interaction with them. That is, it is believed that because this siloxane is highly adherent to F particles, the dispersion stability of F particles is selectively improved in this dispersion, and the decline in liquid properties is suppressed.

[0044] Furthermore, it is believed that the hydrophobic silica and the siloxane work synergistically to improve the dispersion stability of F particles and suppress foaming in the liquid, thereby improving the operability of the dispersion during mixing or coating, and the surface smoothness of the resulting coating and other shaped products.

[0045] The F polymer used in this invention can be hot-meltable or non-hot-meltable, preferably at least a portion of which is hot-meltable.

[0046] As described above, hot-melt polymers are those that do not reach a melt flow rate of 1 to 1000 g / 10 minutes under a load of 49 N.

[0047] When polymer F is thermoplastic, its melting temperature is preferably above 200°C, more preferably above 260°C. When polymer F is thermoplastic, its melting temperature is preferably below 325°C, more preferably below 320°C. In this case, the F particles readily interact with the siloxane, resulting in excellent dispersion stability and workability of the dispersion.

[0048] The glass transition temperature of polymer F is preferably above 50°C, more preferably above 75°C. The glass transition temperature of polymer F is preferably below 150°C, more preferably below 125°C.

[0049] The fluorine content of polymer F is preferably 70% by mass or more, more preferably 72% to 76% by mass.

[0050] The surface tension of polymer F is preferably 16–26 mN / m. Furthermore, the surface tension of polymer F can be measured by placing a droplet of a wetting index reagent (manufactured by Wako Pure Chemicals Co., Ltd.) onto a plate made of polymer F.

[0051] F polymers with high fluorine content have excellent electrical and physical properties, but on the other hand, they have low surface tension and poor adhesion. However, according to the present invention, due to the above-mentioned mechanism of action, it is easy to obtain a dispersion with excellent dispersion stability and operability.

[0052] Polymer F is preferably polytetrafluoroethylene (PTFE), polymers containing TFE units and ethylene units, polymers containing TFE units and propylene units, polymers containing TFE units and units based on perfluoro(alkyl vinyl ether) (PAVE) (PFA), polymers containing TFE units and hexafluoropropylene units (FEP), more preferably PFA and FEP, and even more preferably PFA. These polymers may also contain units based on other comonomers.

[0053] PAVE is preferably CF2=CFOCF3, CF2=CFOCF2CF3 and CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), and more preferably PPVE.

[0054] From the viewpoint of improving adhesion, the thermally fusible F polymer preferably has oxygen-containing polar groups, more preferably has hydroxyl groups or carbonyl groups, and even more preferably has carbonyl groups.

[0055] As a hydroxyl-containing group, it is preferred to have an alcohol-containing hydroxyl group, and more preferably -CF2CH2OH and -C(CF3)2OH.

[0056] As carbonyl groups, carboxyl groups, alkoxycarbonyl groups, amide groups, isocyanate groups, urethane groups (-OC(O)NH2), acid anhydride residues (-C(O)OC(O)-), imide residues (-C(O)NHC(O)-, etc.) and carbonate groups (-OC(O)O-) are preferred, and acid anhydride residues are more preferred.

[0057] When polymer F has oxygen-containing polar groups, the number of oxygen-containing polar groups in polymer F is preferably relative to 1 × 10 6 The number of carbon atoms in the main chain is 10 to 5000, more preferably 100 to 3000. Furthermore, the number of oxygen-containing polar groups in the F polymer can be quantified according to the polymer composition or the method described in International Publication No. 2020 / 145133.

[0058] The oxygen-containing polar group can be contained in the monomer-based unit of the F polymer or in the terminal group of the F polymer backbone, with the former being preferred. Examples of the latter include F polymers having oxygen-containing polar functional groups as terminal groups derived from polymerization initiators, chain transfer agents, etc., and F polymers obtained by plasma treatment or ionizing radiation treatment of F polymers.

[0059] As monomers containing carbonyl groups, itaconic anhydride, citraconic anhydride and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH") are preferred, and NAH is more preferred.

[0060] Polymer F is preferably a polymer containing TFE units and PAVE units, having a carbonyl group. More preferably, it is a polymer containing TFE units, PAVE units, and units based on monomers having carbonyl groups, and comprising, in sequence, 90-99 mol%, 0.99-9.97 mol%, and 0.01-3 mol% of these units relative to all units. Specific examples of such polymer F include the polymer described in International Publication No. 2018 / 16644.

[0061] The D50 of the F polymer 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.

[0062] The preferred specific surface area of ​​F particles is 1–25 m². 2 / g.

[0063] This dispersion may contain two or more types of F particles. When containing two types of F particles, the F particles are preferably particles of a thermoplastic F polymer and particles of a non-thermally plastic F polymer, more preferably particles of a thermoplastic F polymer containing carbonyl groups and TFE units and PAVE units, and particles of non-thermally plastic PTFE.

[0064] In this case, the dispersion stability and operability of this dispersion are likely to be excellent, and the electrical properties of the molded articles formed by this dispersion are likely to be excellent.

[0065] 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 above proportion is preferably 0.1% by mass or more, more preferably 1% by mass or more.

[0066] Furthermore, the D50 of the particles of the thermally fusible F polymer is preferably 1 to 4 μm, and the D50 of the particles of the non-thermally fusible F polymer is 0.1 to 1 μm.

[0067] F particles are particles containing F polymers, preferably particles composed of F polymers.

[0068] F particles may also contain resins or inorganic compounds other than F polymers, and may form a core-shell structure with F polymer as the core and resins or inorganic compounds other than F polymers as the shell, or may form a core-shell structure with F polymer as the shell and resins or inorganic compounds other than F polymers as the core.

[0069] Examples of resins other than F polymers include aromatic polyesters, polyamide-imide, polyimide, and maleimide.

[0070] Examples of inorganic compounds include silicon dioxide and boron nitride.

[0071] The content of F particles in this dispersion is preferably 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 is preferably 60% by mass or less, more preferably 40% by mass or less.

[0072] This siloxane is an organopolysiloxane with dimethylsiloxane as its structural unit, and can have dimethylpolysiloxane units (-(CH3)2SiO) in the main chain. 2 / 2 -), it can also have dimethyl polysiloxane units in the side chain, or it can have dimethyl polysiloxane units in both the main chain and the side chain. As this siloxane, a linear polymer having dimethyl polysiloxane units in the main chain is preferred.

[0073] From the viewpoint of the dispersion stability of this dispersion, the preferred siloxane is a polyoxyethylene-modified polydimethylsiloxane. Examples of polyoxyethylene-modified polydimethylsiloxanes include those with a main chain containing dimethylsiloxane units and side chains containing alkenyl oxide groups, or those with a main chain containing dimethylsiloxane units and end chains containing alkenyl oxide groups.

[0074] As a former type of polyoxyethylene-modified polydimethylsiloxane, it is preferable to contain the formula -(R) in the non-terminal portion of the main chain. 1 (R) 2 SiO 2 / 2 - represents the diorganosiloxane unit. As the latter type of polyoxyethylene-modified polydimethylsiloxane, it is preferable to contain the formula (R) at the end of the main chain. 1 )2(R 2 SiO 2 / 2 - represents the two organosiloxane units.

[0075] R in the formula 1 It indicates an alkyl group, preferably a methyl group.

[0076] R in the formula 2 The group representing a polyoxyalkylene group is preferably of formula -X. 2 -O-(Y 2 ) n -Z 2 The group represented (where X is a radical) 2 Y represents methylene. 2 Indicates polyoxyalkylene group, Z 2 (This represents a hydrogen atom, alkyl group, or acyl group, where n represents an integer from 2 to 100).

[0077] As X 2 Examples include vinyl, propylene, and butene.

[0078] As Y 2 Examples include oxyvinyl and oxypropylene groups.

[0079] As Z 2 The alkyl or acyl group in it can be exemplified by methyl or acetyl groups.

[0080] Furthermore, the polyoxyalkylene groups contained in polyoxyalkylene-modified dimethylsiloxane can be composed of two or more types of alkylene oxides. In the latter case, the different types of alkylene oxides can be randomly linked or block-linked.

[0081] The degree of polymerization of the oxidized alkenyl group in the polyoxyethylene-modified polydimethylsiloxane, i.e., the number of repeating units of the oxidized alkenyl group, 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.

[0082] The preferred siloxane is to use both a hydrophilic polydimethylsiloxane (hereinafter also referred to as "hydrophilic siloxane") and a hydrophobic polydimethylsiloxane (hereinafter also referred to as "hydrophobic siloxane").

[0083] Hydrophilic siloxanes are essentially hydrophilic siloxanes. Here, "essentially hydrophilic" means that even if some functional groups contain hydrophobic groups, as long as the siloxane compound exhibits hydrophilicity, it is acceptable.

[0084] Preferably, the hydrophilic siloxane has a polyoxyethylene content. In this case, the dispersion exhibits excellent dispersion stability and operability.

[0085] As a hydrophilic siloxane, examples of hydrophilic siloxanes in the above-mentioned polyoxyethylene modified polydimethylsiloxanes include, for example, polyoxyethylene modified polydimethylsiloxanes having the structure of formula (I) or (II).

[0086] R 1 2R 3 SiO-((CH3)2SiO) x -(R 1 R 2 SiO) y )-SiR 1 2R 3 (I)

[0087] In equation (I), R 1 R 3 They are alkyl groups having 1 to 18 carbon atoms, R 2 For the formula -R 4 -O(CH2CH2O) a -[CH2(CH3)CHO] b -R 5 The groups represented are integers x from 5 to 150 and y from 1 to 15. R 4 R is an alkylene group having 2 to 6 carbon atoms. 5 It consists of hydrogen atoms, alkyl groups, acetyl groups, or isocyanates with 1 to 6 carbon atoms. 'a' is an integer greater than or equal to 1, and 'b' is an integer greater than or equal to 0. The sum of 'a' and 'b' is between 3 and 80. When 'b' is not 0, the value obtained by dividing 'a' by 'b' ranges from 0.25 to 4.

[0088] R 1 R 3 Preferably, all are methyl, R 3 Depending on the circumstances, it can also be an alkyl group other than methyl.

[0089] R 6 2R 7 SiO-((CH3)2SiO) n -SiR 6 2R 7 (II)

[0090] In equation (II), R 6 R is an alkyl group having 1 to 18 carbon atoms. 7 For the formula -R 8 -O(CH2CH2O) c -R 9 The group to be represented, where c is an integer from 20 to 100. R 8 R is an alkylene group having 2 to 6 carbon atoms. 9 It consists of hydrogen atoms, alkyl groups, acetyl groups, or isocyanates with 1 to 6 carbon atoms.

[0091] R 6 Methyl is preferred.

[0092] Hydrophobic siloxanes are siloxanes that are substantially hydrophobic. Here, substantially hydrophobic means that even if some functional groups contain hydrophilic groups, as long as the siloxane compound exhibits hydrophobicity, it is acceptable.

[0093] From the perspectives of defoaming properties and operability, the optimal viscosity of hydrophobic siloxanes, measured using an Ostwald viscometer at 25°C, is 10–100,000 mmHg. 2 / s, more preferably 50~10000mm 2 / s.

[0094] This silica can be either wet silica or dry silica. Examples of this silica include precipitated silica, silica dry gel, and fumed silica, specifically commercial products such as Nipsil (manufactured by Tosoh Silicon Chemical Co., Ltd.), SYLYSIA (manufactured by Fuji Silicon Chemical Co., Ltd.), and Aerosil (manufactured by AEROSIL Co., Ltd.).

[0095] The methanol wetting rate of this silica is preferably 30–75%, more preferably 40–75. Methanol wetting rate refers to the lower limit of the methanol concentration (volume %) of the aqueous methanol solution used to disperse the total amount of hydrophobic silica in a 10 mL test tube after adding 5 mL of methanol-water solution and 0.2 g of hydrophobic silica, inverting the tube 20 times, and allowing it to stand for 2 minutes. Methanol wetting rate is sometimes also referred to as the M value. This silica with this methanol wetting rate achieves a balance between its dispersion state and sedimentation or floating state in a liquid, and in addition to the synergistic effect with the siloxane, its defoaming effect is easily enhanced, and the defoaming properties and other liquid properties of the dispersion are easily improved.

[0096] The primary particle size of this silica is preferably 0.001 to 2.0 μm, more preferably 0.01 to 1.0 μm.

[0097] The specific surface area of ​​this silica, as measured by the BET method, is preferably 100–700 m². 2 / g, more preferably 100-500m 2 / g.

[0098] The silica, whose primary particle size and specific surface area are within the above-mentioned range, achieves a balance between its dispersion state and sedimentation or floating state in a liquid, and in addition to the synergistic effect with the siloxane, its defoaming effect is easily enhanced, and its defoaming properties and other liquid properties of the dispersion are easily improved.

[0099] This silica can be surface-treated. Surface treatment can be performed, for example, using a mixing and dispersing device such as a Henschel mixer, a Lodige mixer, or a high-speed mixer, or by adding raw silica powder to the aforementioned device, spraying an organopolysiloxane before stirring, or spraying an organopolysiloxane while stirring. Heating or the addition of an alkaline catalyst such as ammonia may also be performed as needed. In this case, treatment is preferably performed at a temperature of room temperature to 100°C, more preferably at 50 to 80°C for 10 to 120 minutes, and even more preferably for 15 to 60 minutes.

[0100] Furthermore, the amount of surface treatment agents such as organopolysiloxanes relative to the silica varies depending on the specific surface area of ​​the silica, but the specific surface area of ​​the silica, measured in BET form, is generally 100–700 m². 2 In the case of / g, it is preferably 1 to 50 parts by mass relative to 100 parts by mass of this silica, more preferably 5 to 30 parts by mass.

[0101] This dispersion preferably contains 11 parts by mass or less of the siloxane relative to 100 parts by mass of F particles and 0.5 parts by mass or less of the silica. This dispersion may contain siloxane and silica with more than 0 parts by mass of F particles relative to 100 parts by mass, but from the viewpoint of effectiveness, it is preferable to contain 0.1 parts by mass or more of the siloxane and 0.01 parts by mass or more of the silica.

[0102] When this dispersion uses both the aforementioned hydrophilic and hydrophobic siloxanes, it preferably contains 10 parts by mass or less of a hydrophilic siloxane, 1 part by mass or less of a hydrophobic siloxane, and 0.5 parts by mass or less of silica relative to 100 parts by mass of F particles. When this dispersion uses both the aforementioned hydrophilic and hydrophobic siloxanes, it preferably contains 0.1 parts by mass or more of a hydrophilic siloxane, 0.1 parts by mass or more of a hydrophobic siloxane, and 0.01 parts by mass or more of silica relative to 100 parts by mass of F particles.

[0103] In addition to the aforementioned siloxane and silica, this dispersion may also contain a polyether compound. In this case, the polyether compound interacts with the F particles and also has an antifoaming effect, thus improving the dispersion stability and workability of the dispersion. The polyether compound refers to a polyoxyethylene compound represented by the following formula (III).

[0104] R 10 O-(R 11 O) z -R 10 (III)

[0105] In equation (III) above, R 10 It is a hydrogen atom or a monovalent organic group. Two Rs 10 They can be the same or different. z is an integer from 2 to 150.

[0106] 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 stearoyl. 11 It is ethylidene or propyleneide. Multiple R 11 It can be two or more different groups.

[0107] From the viewpoint of dispersion stability and operability during coating, the weight-average molecular weight of the polyether compound determined by GPC is preferably 500 to 5000, more preferably 1000 to 4000.

[0108] When this dispersion contains the aforementioned polyether compound, from the viewpoint of dispersion stability, this dispersion preferably contains 10 parts by mass or less of the siloxane, 0.5 parts by mass or less of the silica, and 1 part by mass or less of the aforementioned polyether compound relative to 100 parts by mass of F particles. When this dispersion contains the aforementioned polyether compound, this dispersion preferably contains 0.1 parts by mass or more of the siloxane, 0.01 parts by mass or more of the silica, and 0.1 parts by mass or more of the aforementioned polyether compound relative to 100 parts by mass of F particles.

[0109] When the above-mentioned polyether compound is incorporated, the siloxane is preferably the above-mentioned hydrophilic siloxane.

[0110] This dispersion comprises the aforementioned F particles, the siloxane, the silica, 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.

[0111] This dispersion may also contain water-soluble liquid compounds as the dispersion medium. Examples of water-soluble liquid compounds include water-soluble alcohols or water-soluble amides.

[0112] 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.

[0113] 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.

[0114] The thixotropic ratio of this dispersion is preferably 1.0 to 3.0.

[0115] 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. Each viscosity measurement was repeated three times, and the average of the three measurements was used.

[0116] The pH value of this dispersion is preferably greater than 7, and more preferably 8 to 10. Under this condition, the siloxane is not easily decomposed, and the long-term storage properties of this dispersion are excellent.

[0117] To adjust the pH value, 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.

[0118] This dispersion may contain nonionic surfactants.

[0119] As nonionic surfactants, glycol surfactants, acetylene surfactants, organosilicon surfactants, and fluorinated surfactants are preferred, with organosilicon surfactants being more preferred. Two or more nonionic surfactants may be used. When using two nonionic surfactants, a combination of an organosilicon surfactant and a glycol surfactant is preferred.

[0120] Specific examples of nonionic surfactants include the "FTERGENT" series (manufactured by Neos Corporation), the "SURFLON" series (manufactured by AGC Seimei Chemical Co., Ltd.), the "MEGAFACE" series (manufactured by DIC Corporation), the "UNIDYNE" series (manufactured by Daikin Industries, Ltd.), and "BYK-347". "BYK-349", "BYK-378", "BYK-3451", "BYK-3455", "BYK-3456" (manufactured by BYK Chemical Japan Co., Ltd.), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Industry Co., Ltd.), "Tergitol" series ("Tergitol TMN-100X" manufactured by Dow Chemical Company, etc.).

[0121] When the dispersion contains a nonionic surfactant, the content of the nonionic surfactant in the dispersion is preferably 1 to 15% by mass.

[0122] This dispersion may also contain resins different from those of polymer F.

[0123] Resins other than polymer F can be thermosetting or thermoplastic. Resins other than polymer F can be dissolved in or dispersed in this dispersion. Resins other than polymer F can also be included in this dispersion as precursors. Examples of resins other than polymer F include polyester resins (such as liquid crystal aromatic polyesters), imide resins, epoxy resins, maleimide resins, polyurethane resins, polyphenylene ether resins, polyphenylene ether resins, polyphenylene sulfide resins, and fluoropolymers other than polymer F.

[0124] As a resin other than F polymers, aromatic polymers or fluoropolymers other than F polymers are preferred.

[0125] Examples of aromatic polymers include aromatic polyimides, aromatic polyimide precursors that are polyamic acids or their salts, aromatic polyamide imides, aromatic polyamide imide precursors, aromatic polyether imides, and aromatic polyether imide precursors. Aromatic polymers are preferably water-soluble, more preferably water-soluble aromatic polyimide precursors, and water-soluble polyamide imides or their precursors.

[0126] Examples of water-soluble aromatic polyimide precursors include polyamic acids and their salts, which are obtained by polymerizing tetracarboxylic dianhydrides with diamines.

[0127] 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.

[0128] Examples of tetracarboxylic dianhydrides include pyromellitic dianhydride and biphenyltetracarboxylic dianhydride. Examples of diamines include phenylenediamine, 3,3'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl ether.

[0129] Examples of diisocyanates include 4,4'-diphenylmethane diisocyanate, phenyl dimethyl isocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, and 3,3'-diphenylmethane diisocyanate.

[0130] The number-average molecular weight (Mn) of the aromatic polymer is preferably 5,000 to 50,000.

[0131] The preferred acid value of the aromatic polymer is 20–100 mg / KOH.

[0132] The acid value of aromatic polymers can be determined by titrating a mixed solution of 0.5 g of the 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 containing 0.05 mol / L potassium hydroxide ethanol solution. Alternatively, in the case where the aromatic polymer has an anhydride group, the acid value is the acid value of the aromatic polymer when that anhydride group is open.

[0133] When the dispersion contains an aromatic polymer, the content of the aromatic polymer is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. The content of the aromatic polymer is preferably 30% by mass or less, more preferably 10% by mass or less.

[0134] Examples of fluoropolymers other than F polymers include polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride.

[0135] When the dispersion contains fluoropolymers other than F polymers, the content of 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.

[0136] This dispersion may further contain inorganic fillers other than hydrophobic silica. Two or more types of inorganic fillers may be used.

[0137] The inorganic filler is preferably spherical, needle-like, fibrous, or plate-like in shape, more preferably spherical, scaly, or layered, and even more preferably spherical or scaly.

[0138] Spherical inorganic packing materials are preferably approximately spherical. Approximately spherical means that when observed by scanning electron microscopy (SEM), the proportion of inorganic packing materials with a minor axis to major axis ratio of 0.7 or higher is 95%.

[0139] The aspect ratio of non-spherical inorganic packing material is preferably 2 or more, more preferably 5 or more. The aspect ratio is preferably 10000 or less.

[0140] As inorganic fillers, carbon fillers, inorganic nitride fillers, and inorganic oxide fillers are preferred, and carbon fiber fillers, boron nitride fillers, aluminum nitride fillers, beryllium oxide fillers, silica fillers other than hydrophobic silica, wollastonite fillers, talc fillers, cerium oxide fillers, aluminum oxide fillers, magnesium oxide fillers, zinc oxide fillers, and titanium oxide fillers are more preferred. Boron nitride fillers and silica fillers other than hydrophobic silica are even more preferred.

[0141] In addition, the silica filler other than hydrophobic silica is a hydrophilic silica filler, preferably untreated or treated with a hydrophilic surface treatment agent.

[0142] The D50 of the inorganic packing is preferably below 20 μm, more preferably below 10 μm. The D50 is preferably above 0.01 μm, more preferably above 0.1 μm. The specific surface area of ​​the inorganic packing is preferably 1–20 m². 2 / g.

[0143] The surface of inorganic fillers can be treated with silane coupling agents.

[0144] The preferred silane coupling agents are silane coupling agents with functional groups, such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0145] Specific examples of silica fillers other than hydrophobic silica include the "admafin" series (manufactured by Adma Technology Co., Ltd.), the "SFP" series (manufactured by Denka Co., Ltd.), and the "E-SPHERES" series (manufactured by Pacific Cement Co., Ltd.).

[0146] As a specific example of zinc oxide filler, the "FINEX" series (manufactured by Sakai Chemical Industry Co., Ltd.) can be cited.

[0147] Specific examples of titanium oxide fillers include the "TIPAQUE" series (manufactured by Ishihara Sangyo Co., Ltd.) and the "JMT" series (manufactured by Teika Co., Ltd.).

[0148] As a specific example of talc fillers, the "SG" series (manufactured by Japan Talc Corporation) can be cited.

[0149] As a specific example of block talc filler, the "BST" series (manufactured by Japan Talc Co., Ltd.) can be cited.

[0150] Specific examples of boron nitride fillers include the "UHP" series (manufactured by Showa Denko Co., Ltd.), the "GP" and "HGP" grades of the "Denka boron nitride" series (manufactured by Denka Co., Ltd.).

[0151] When the dispersion contains inorganic fillers other than hydrophobic silica, the content of inorganic fillers in the dispersion is preferably 10 to 40% by mass.

[0152] This dispersion may also contain polyols other than the polyether compounds described above. Such polyols are compounds having two or more hydroxyl groups other than the polyoxyethylene compounds represented by formula (III) above, and are referred to as polyols below.

[0153] As a polyol, aliphatic polyols containing 2 or 3 hydroxyl groups, free of nitrogen atoms, and with a boiling point above 100°C are preferred.

[0154] The boiling point of the polyol is preferably above 150°C, more preferably above 200°C. The boiling point is preferably below 340°C.

[0155] Furthermore, the polyol is preferably a polyol that is mixed with water.

[0156] 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.

[0157] 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 become excellent.

[0158] Polyols can be used alone or in combination with two or more.

[0159] When this dispersion contains a polyol, the mass ratio of the polyol to water is preferably 0.2 or more, more preferably 0.5 or more. This mass ratio is preferably 10 or less, more preferably 5 or less. Within this range, the aggregation inhibition and rheological regulation effects of the polyol are well balanced, and the dispersion readily exhibits excellent dispersion stability.

[0160] In addition to the above-mentioned components, this dispersion may also contain additives such as thixotropic agents, viscosity modifiers, defoamers, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, release agents, surface treatment agents, flame retardants, and various fillers, as needed.

[0161] This dispersion is preferably prepared by the following methods: adding F particles, the siloxane, and the silica, as well as other components such as the aforementioned polyether compound, inorganic filler, resin different from the F polymer, and additives, to water in one step and mixing; adding F particles and other components to water sequentially and mixing; pre-mixing F particles with water and other components with water separately and then mixing them; or mixing F particles with other components and then mixing them with water. These mixing methods can be carried out in batches or continuously.

[0162] Examples of mixing devices include: agitators with blades such as Henschel mixers, pressure kneaders, Banbury mixers, and planetary mixers; pulverizers with media such as ball mills, pulverizers, basket mills, sand mills, sand grinders, DYNO mills, DISPERMAT dispersers, SC mills, Spike mills, or stirred mills; and dispersion devices with other mechanisms such as microfluidizers, nano-dispersants, Ultimaizer dispersers, ultrasonic homogenizers, dissolvers, dispersers, high-speed impeller dispersers, self-rotating and revolution-rotating mixers, or thin-film gyratory high-speed mixers.

[0163] As a preferred method for manufacturing this dispersion, an example is a method in which F particles are pre-mixed with a portion of water to obtain a compound, and then the compound is added to the remaining water to obtain a dispersion. If this dispersion also contains other components such as polyether compounds, inorganic fillers, and other resins, these other components can be mixed during mixing or added.

[0164] The compound obtained from mixing can be either a paste or a wet powder. A paste refers to a paste with a viscosity of 1,000 to 100,000 mPa·s. A wet powder refers to a wet powder with a viscosity of 10,000 to 100,000 Pa·s as measured by a capillary rheometer.

[0165] In addition, the viscosity measured by the capillary rheometer refers to the viscosity measured using a capillary with a length of 10 mm and a radius of 1 mm, at a furnace diameter of 9.55 mm, a weighing sensor capacity of 2 t, a temperature of 25 °C, and a shear rate of 1 s. -1 The value was measured under the specified conditions.

[0166] A planetary mixer is preferred for mixing during the compounding process. A planetary mixer is a mixing device with two shafts of stirring blades that rotate on their own axis and revolve around the sun.

[0167] The mixing during addition is preferably performed using a thin-film gyratory high-speed mixer. A thin-film gyratory high-speed mixer is a stirring device that spreads F particles and liquid dispersion media into a thin film on the inner wall of a cylindrical stirring tank and rotates it while applying centrifugal force to mix them.

[0168] This method manufactures the laminate by forming a layer of the dispersion (hereinafter also referred to as a "wet film layer") on the surface of a substrate, followed by heating to remove water from the dispersion layer to form a layer containing polymer F (hereinafter also referred to as a "dry film layer") on the surface of the substrate. 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 on the surface of the substrate layer (hereinafter also referred to as an "F layer") can be obtained. The formation of the F layer can be performed after the formation of the dry film layer, or it can be performed in a process separate from the formation of the dry film layer.

[0169] 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 polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamide-imide, liquid crystal polyester, and F polymer; prepreg substrates used as precursors for fiber-reinforced resin substrates; ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates.

[0170] Among these substrates, copper foil and polyimide film are preferred as substrates, and copper foil with low roughness is more preferred.

[0171] Examples of substrate shapes include planar, curved, and uneven surfaces. Furthermore, substrate properties can be any of the following: foil, plate, film, or fibrous.

[0172] The ten-point average roughness of the substrate surface is preferably 0.01 to 0.05 μm.

[0173] The substrate surface can be treated with silane coupling agents or plasma treatment.

[0174] The preferred silane coupling agents are silane coupling agents with functional groups, such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0175] As a method for forming a wet film layer on the surface of a substrate using this dispersion, examples include coating. Examples of coating methods include coating, droplet spraying, and dipping, with preferred methods being roller coating, blade coating, bar coating, mold coating, or spray coating.

[0176] The heating process for forming a dry film layer by removing moisture from the wet film layer is preferably performed at 100–200°C for 0.1–30 minutes. During this heating, it is not necessary to completely remove the water; rather, the water is removed to the extent that the layer formed by the accumulation of F particles can maintain a self-supporting membrane. Furthermore, air can be blown during heating to promote water removal through air drying.

[0177] Furthermore, if the dispersion also contains a water-soluble liquid compound other than water as a liquid dispersion medium, it is preferable that the water-soluble liquid compound other than water is also removed together with water by the above-mentioned heating.

[0178] The F layer can be formed by firing the F polymer through heating the dry film layer. The temperature can be further increased during the heating stage described above for forming the dry film layer to fire the F polymer. Heating the F polymer during firing is more preferably performed at 360–400°C for 0.1–30 minutes. If the F polymer is a thermoplastic F polymer, heating the F polymer during firing is preferably performed at a temperature above the melting temperature of the F polymer.

[0179] Examples of heating devices used for the formation of the dry film layer and the F layer include ovens and ventilated drying furnaces. The heat source in the device can be a contact heat source such as hot air or a heating plate, or a non-contact heat source such as infrared radiation.

[0180] Each heating step can be performed under normal pressure or under reduced pressure.

[0181] The atmosphere during heating can be any of the following inert gas atmospheres: air, helium, neon, argon, nitrogen, etc.

[0182] Layer F is formed by contacting the dispersion with a substrate and then heating it. These processes can each be performed once or repeated two or more times. For example, the dispersion can be coated onto the substrate surface and heated to form a dry film layer, and then layer F can be formed. A second layer of layer F can then be formed by further coating the dispersion onto the surface of layer F and heating it. Alternatively, layer F can be formed by further coating the dispersion onto the substrate surface and heating it during the stage of forming a dry film layer.

[0183] This dispersion can contact only one surface of the substrate or both surfaces of the substrate. The former case yields a laminate having a substrate layer and an F layer on a single surface of the substrate layer, while the latter case yields a laminate having a substrate layer and an F layer on both surfaces of the substrate layer.

[0184] Preferred examples of laminates include metal-coated laminates having a metal foil and an F layer on at least one surface of the metal foil, and multilayer films having a polyimide film and F layers on both surfaces of the polyimide film.

[0185] 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.

[0186] The peel strength between the F layer and the substrate layer is preferably 10 to 100 N / cm.

[0187] The substrate layer can be further removed from the laminate to obtain a film containing the F polymer.

[0188] This laminate has excellent electrical properties, making it suitable as a printed circuit board material. Specifically, it can be used as a flexible metal-clad laminate or a rigid metal-clad laminate in the manufacture of printed circuit boards. It is particularly preferred as a flexible metal-clad laminate in the manufacture of flexible printed circuit boards.

[0189] In the manufacture of this printed circuit board, an interlayer insulating film can be formed on the transmission circuit, a solder resist can be laminated on the transmission circuit, and a coating film can be laminated on the transmission circuit. These interlayer insulating films, solder resists, and coating films can all be formed using this dispersion.

[0190] This laminate can be used for antenna components, printed circuit boards, aircraft components, automotive components, sporting goods, food industry products, heat dissipation components, coatings, cosmetics, etc. It can also be used in printed circuit boards as a novel material to replace traditional glass epoxy boards, preventing temperature rise in printed circuit boards with high-density mounted electronic components.

[0191] Specifically, it can be used as a wire sheathing material for aircraft wires, enameled wire sheathing material for motors in electric vehicles, electrical insulating tape, insulating tape for oil drilling, materials for printed circuit boards, separation membranes such as precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, and gas separation membranes, electrode adhesives for lithium secondary batteries and fuel cells, covers for photocopier rollers, furniture, automotive dashboards, and household appliances, sliding parts such as load bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, conveyor belts, and food conveyor belts, wear-resistant pads, wear-resistant strips, tube lights, test sleeves, wafer guides, and wear parts for centrifugal pumps, pumps for supplying hydrocarbons / chemicals and water, tools such as shovels, files, awls, and saws, sheathing materials for boilers, hoppers, pipes, ovens, baking molds, chutes, plastic molds, toilets, and containers, power devices, transistors, thyristors, rectifiers, transformers, and power MOSFETs. FETs, CPUs, heat sinks, metal heat sinks, blades of windmills or wind power generation equipment or aircraft, etc.

[0192] More specifically, it can be used as a sealing material for computer or monitor frames, electronic device materials, automotive interior and exterior trim, processing machines or vacuum furnaces that perform heat treatment under low oxygen conditions, plasma processing devices, etc., or heat dissipation components in processing units such as sputtering or various dry etching devices.

[0193] In addition, this dispersion can also be used for impregnating and drying insulating layers of printed circuit boards, thermal interface materials, power module substrates, coils used in power equipment such as electric motors to form thermally conductive and heat-resistant coatings; for bonding ceramic or metal components in automotive engines; for imparting corrosion resistance to heat exchangers or the fins or tubes constituting heat exchangers; and for coating the inside and outside of glass containers. It is particularly suitable for coatings that impart impact resistance. Examples of glass containers include vials, syringes, syringes with needles, tubular syringes, and ampoules.

[0194] In addition, this dispersion can be used as an electrode bonding material, a membrane coating material, and a coating material for positive or negative electrodes in electrochemical devices with electrodes, such as lithium-ion batteries, secondary batteries, primary batteries, free radical batteries, solar cells, especially dye-sensitized solar cells, fuel cells, lithium-ion capacitors, hybrid capacitors, double-layer capacitors, aluminum electrolytic capacitors, tantalum electrolytic capacitors, electrochromic elements, electrochemical conversion elements, and various electrochemical sensors.

[0195] Furthermore, when this dispersion contains conductive fillers, it can also be suitably used in applications requiring conductivity, such as the printed electronics field. Specifically, it can be used to manufacture conductive components such as printed circuit boards, sensor electrodes, displays, substrates, RFID (Radio Frequency Identification), solar power generation, lighting, disposable electronic devices, automotive heaters, electromagnetic interference (EMI) shielding covers, and membrane switches.

[0196] Furthermore, the sintered product obtained from this dispersion can also be used as an adhesive in semiconductor elements, high-density substrates, or module components for bonding IC chips or electronic components such as resistors and capacitors mounted on substrates, bonding circuit boards to heat sinks, and bonding LED chips to substrates. Moreover, the sintered product can also be used as a conductive bonding material between circuit wiring and electronic components during the assembly process of electronic components (as a substitute for solder bonding). Additionally, it can be used as an adhesive between ceramic or metal components in automotive engines. Furthermore, the sintered product can also be used for the purposes described in International Publication No. 2016 / 017801, paragraph

[0149] .

[0197] The manufacturing method of the dispersion and the laminate has been described above, but the present invention is not limited to the configuration of the above embodiments.

[0198] For example, in the configuration of the above-described embodiments, this dispersion can be supplemented with any other components, or it can be replaced with any component that performs the same function. Furthermore, in the manufacturing method of this laminate in the above-described embodiments, any other steps can be supplemented, or it can be replaced with any step that performs the same function.

[0199] Example

[0200] The present invention will be described in detail below through embodiments, but the present invention is not limited thereto.

[0201] 1. Preparation of each ingredient

[0202] [F particle]

[0203] F particles 1: constitute each 1 × 10⁻⁶ TFE units, NAH units, and PPVE units, comprising 97.9 mol%, 0.1 mol%, and 2.0 mol% respectively. 6 Particles (D50: 1.7 μm) of a polymer powder with 1000 carbonyl groups in its main chain (melting temperature: 300 °C).

[0204] F particle 2: Particles (D50: 1.8 μm) constituting a polymer powder (melting temperature: 305 °C) without oxygen-containing polar groups, comprising 98.7 mol% and 1.3 mol% TFE units and PPVE units respectively.

[0205] [Siloxane compounds]

[0206] Siloxane 1: A hydrophilic polyoxyethylene-modified polydimethylsiloxane (BYK-3450) with dimethylsiloxane units in the main chain and oxyvinyl groups in the side chains.

[0207] Siloxane 2: Hydrophobic polydimethylsiloxane (viscosity at 25°C, measured using an Ostwald viscometer: 8000 mm). 2 / s)

[0208] Hydrophobic silica

[0209] Silica 1: Hydrophobic silica with both ends surface-treated with hydroxydimethylpolysiloxane (specific surface area: 300 m²) 2 / g, "AEROSIL 300" manufactured by Japan AEROSIL Co., Ltd.)

[0210] Silica 2: Surface-treated hydrophobic silica with trimethylsilyl groups (primary particle size: 0.01 μm, specific surface area: 130 m²). 2 / g, methanol wetting rate: 70, "RX200" manufactured by AEROSIL Co., Ltd. of Japan)

[0211] Silica 3: Surface-treated hydrophobic silica with alkyl silane groups (primary particle size: 0.01 μm, specific surface area: 150 m²). 2 / g, methanol wetting rate: 50, "R805" manufactured by AEROSIL Co., Ltd. of Japan)

[0212] Silica 3: Surface-treated hydrophobic silica with dimethylsilyl groups (primary particle size: 0.01 μm, specific surface area: 170 m²). 2 / g, methanol wetting rate: 35, "R974" manufactured by AEROSIL Co., Ltd. of Japan)

[0213] [Polyether]

[0214] Polyether 1: A ring-opening addition polymer of ethylene oxide and propylene oxide with 25 ethylene oxide units and 35 propylene oxide units.

[0215] [Aromatic polyamide-imide varnish]

[0216] Varnish 1: A water-based varnish containing the aramid-imide precursor (PAI1).

[0217] [Polyurethane]

[0218] Polyurethane 1: Polyurethane thickener ("ADEKANOL UH450VF" manufactured by ADEKA Corporation)

[0219] 2. Preparation of dispersion

[0220] Water and F particles 1 were placed in a container containing zirconia balls, followed by the addition of siloxane 1, siloxane 2, silica 1, varnish 1, and polyurethane 1. The container was rotated, and 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 silica 1, 0.1 parts by mass of PAI 1, and 0.8 parts by mass of polyurethane 1 were added to obtain a dispersion 1 containing F particles 1.

[0221] Except for changing the composition of the dispersion according to Table 1, dispersions 2 to 6 were obtained in the same manner as dispersion 1.

[0222] [Table 1]

[0223]

[0224] All figures are in parts by weight.

[0225] 3. Fabrication of laminated bodies

[0226] A dispersion 1 was coated onto the surface of a 18 μm thick strip of copper foil using a small-diameter gravure reverse coating method to form a wet film layer. Next, the copper foil with the wet film layer was passed through a drying oven at 110°C for 5 minutes to dry it, obtaining a dry film layer. Then, the dry film layer was heated at 380°C for 3 minutes in an oven under a nitrogen atmosphere. This produced a laminate 1 having a copper foil and a 25 μm thick polymer layer containing polymer 1 (F) on its surface.

[0227] Except for changing dispersion 1 to dispersion 2 to 6, laminates 2 to 6 were manufactured in the same manner as laminate 1.

[0228] 4. Evaluation

[0229] 4-1. Evaluation of Dispersion Stability

[0230] Each dispersion (18 mL) was placed in a solenoid tube (internal volume: 30 mL) and allowed to stand at 25 °C for 14 days. Based on the total height of the dispersion and the height of the sedimentation layer (dispersion layer) in the solenoid tube after standing, the dispersion ratio was calculated using the following formula to further confirm the redispersibility after hand-vibration of the solenoid tube, and the dispersion stability was evaluated according to the following criteria.

[0231] [Evaluation Criteria]

[0232] 〇: The dispersion ratio is above 60%, and it is easy to redisperse.

[0233] △: The dispersion layer ratio is less than 60%, but redispersion is easy.

[0234] ×: The dispersion layer ratio is less than 60%, and redispersion is difficult.

[0235] 4-2. Evaluation of Coating / Film Properties

[0236] The surface of the polymer layer of the laminate obtained when the laminate was made from each dispersion was visually inspected for cracks, and the film-forming properties were evaluated according to the following criteria.

[0237] [Evaluation Criteria]

[0238] ◎: No cracks observed

[0239] ○: Small cracks were observed at the edge of the polymer layer.

[0240] △: Small cracks were observed throughout the polymer layer.

[0241] ×: Large cracks were observed throughout the polymer layer.

[0242] 4-3. Evaluation of the electrical properties of laminates

[0243] Rectangular test pieces, 100 mm in length and 50 mm in width, were cut from each laminate and etched with ferric chloride aqueous solution to remove the copper foil, yielding polymer layer monomers. The dielectric loss tangent of the polymer layer was measured using the SPDR (Separated Column Dielectric Resonant Cavity) method (measurement frequency: 10 GHz), and evaluated according to the following criteria.

[0244] [Evaluation Criteria]

[0245] 〇: Dielectric loss tangent is less than 0.0020

[0246] △: Dielectric loss tangent is above 0.0020 and below 0.0025.

[0247] ×: Dielectric loss tangent greater than 0.0025

[0248] 4-4. Evaluation of the peel strength of laminates

[0249] Rectangular test pieces (100 mm long and 10 mm wide) were cut from each laminate. The pieces were fixed 50 mm from one end along their length. The metal foil was peeled from the polymer layer at a 90° angle relative to the test piece from the other end along the length, with a tensile speed of 50 mm / min. The maximum load at this point is the peel strength. The peel strength was evaluated according to the following criteria.

[0250] [Evaluation Criteria]

[0251] ○: Peel strength greater than 12 N / cm

[0252] △: Peel strength is above 8 N / cm and below 12 N / cm

[0253] ×: Peel strength less than 8 N / cm

[0254] These evaluation results are summarized in Table 2.

[0255] [Table 2]

[0256] Dispersion 1 2 3 4 5 6 Dispersion stability ○ ○ ○ △ × × Layered bodies 1 2 3 4 5 6 Coating / Film Forming Properties ◎ ◎ ○ △ × × Electrical properties of laminates ○ ○ ○ △ - - peel strength of laminate ○ ○ △ △ - -

[0257] Except for replacing silica 1 in the manufacture of dispersion 2 with silica 2, silica 3, or silica 4, dispersion 21 containing silica 2, dispersion 31 containing silica 3, and dispersion 41 containing silica 4 were obtained in the same manner. The dispersion stability of each dispersion was the same as that of dispersion 2, and the dispersion stability of dispersion 31 was particularly excellent. Furthermore, after mixing 25 parts by mass of boron nitride particles with 100 parts by mass of each dispersion by shear stirring, dispersion 21 and dispersion 31 produced less foaming than dispersion 41, and the defoaming properties of dispersion 21 were also particularly excellent.

[0258] Alternatively, when using siloxane 2 and silica 1 together, they can be pre-mixed and used as a silicone oil compound. This can also be replaced by commercially available products such as BYK-017, BYK-1786, and BYK-1789 (all manufactured by BYK Chemicals Japan Co., Ltd.).

[0259] When using polyether 1 and silica 1 together, they are also pre-mixed and treated before being used as a silicone oil compound. This can also be replaced by commercially available products such as BYK-012 (manufactured by BYK Chemicals Japan Co., Ltd.).

[0260] The results above demonstrate that this dispersion exhibits excellent dispersion stability, ease of application during coating, and surface smoothness of the resulting coating film. Furthermore, the laminate obtained from this dispersion fully possesses the electrical properties of the F polymer and exhibits excellent peel strength to the substrate.

[0261] Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-131924, filed on August 13, 2021, are incorporated herein as a disclosure of the present invention.

Claims

1. An aqueous dispersion comprising particles containing a tetrafluoroethylene polymer, a polydimethylsiloxane compound, hydrophobic silica, and water. The tetrafluoroethylene-based polymers comprise tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units, and have a melting temperature above 200°C and below 320°C. The methanol wetting value of the hydrophobic silica is 40-75.

2. The aqueous dispersion as described in claim 1, wherein, At least a portion of the polydimethylsiloxane compounds are hydrophilic polydimethylsiloxanes having polyoxyethylene properties.

3. The aqueous dispersion as described in claim 1 or 2, wherein, The polydimethylsiloxane compound comprises a hydrophilic polydimethylsiloxane having a polyoxyethylene content and a viscosity of 10 to 100,000 mm. 2 / s of hydrophobic polydimethylsiloxane.

4. The aqueous dispersion as described in claim 1 or 2, wherein, The primary particle size of the hydrophobic silica is 0.01–20 μm.

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

6. The dispersion as described in claim 1 or 2, wherein, The content of particles containing tetrafluoroethylene polymers is above 30% by mass.

7. The aqueous dispersion as described in claim 1 or 2, wherein, The particles comprising, relative to 100 parts by weight, are 11 parts by weight or less of the polydimethylsiloxane compound and 0.5 parts by weight or less of the hydrophobic silica.

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

9. The aqueous dispersion as described in claim 8, wherein, The polyether compound contains less than 1 part by mass of particles containing the tetrafluoroethylene-based polymer relative to 100 parts by mass.

10. The aqueous dispersion as described in claim 1 or 2, wherein, The tetrafluoroethylene polymers are polymers containing oxygen-containing polar groups.

11. The aqueous dispersion as described in claim 1 or 2, wherein, The particles containing tetrafluoroethylene polymers include particles containing thermally fusible tetrafluoroethylene polymers and particles containing non-thermally fusible tetrafluoroethylene polymers.

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

13. The manufacturing method as described in claim 12, wherein, The layer containing a tetrafluoroethylene-based polymer, formed by heating to remove the water, is then fired.

14. The manufacturing method as described in claim 12 or 13, wherein, The thickness of the layer containing the tetrafluoroethylene polymer is greater than 10 μm.

Images