WO2021132055A1

WO2021132055A1 - Dispersion liquid

Info

Publication number: WO2021132055A1
Application number: PCT/JP2020/047359
Authority: WO
Inventors: 敦美山邊; 渉笠井; 創太結城
Original assignee: Ａｇｃ株式会社
Priority date: 2019-12-25
Filing date: 2020-12-18
Publication date: 2021-07-01
Also published as: TW202132457A; CN115003749B; CN115003749A; KR20220120546A; JPWO2021132055A1

Abstract

Provided is a dispersion liquid comprising a tetrafluoroethylene-based polymer, an inorganic filler, and a compound made from a polymer that has a ester bond, an imide bond or an amide bond or made from a precursor of said polymer, wherein said dispersion liquid has excellent state stability, and can form a molded object having, to a high degree, the physical properties of each component therein.　The dispersion liquid according to the present invention comprises: a tetrafluoroethylene-based polymer; an inorganic filler; a compound P made from a polymer that has an ester bond, an imide bond, or an amide bond, or made from a precursor of said polymer; a liquid amide; and at least one liquid compound selected from the group consisting of ketones, esters, and aromatic hydrocarbons.

Description

Dispersion

The present invention is a dispersion containing a tetrafluoroethylene polymer powder, an inorganic filler, a compound P composed of a polymer having an ester bond, an imide bond or an amide bond, or a precursor of such a polymer, and a predetermined liquid dispersion medium. And a method for producing the same, and a method for producing a laminate having a polymer layer formed from such a dispersion.

Tetrafluoroethylene-based polymers such as polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoro (alkyl vinyl ether) (PFA), and a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP) are releasable. It has excellent physical properties such as electrical properties, water and oil repellency, chemical resistance, weather resistance, and heat resistance, and is used in various industrial applications.
As a coating agent for imparting these physical properties to the surface of the base material, a dispersion liquid containing a powder of a tetrafluoroethylene polymer is known. In Patent Document 1, from the viewpoint of improving the state stability, in addition to the powder of PTFE, it is selected from the group consisting of _{Al 2} O ₃ , SiO ₂ , CaCO ₃ , ZrO ₂ , SiC, Si ₃ N _{4 and Zn O.} A non-aqueous dispersion liquid in which an inorganic filler composed of at least one kind of ceramics (inorganic compound) is blended is described (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-194017

However, if the dispersion liquid of the tetrafluoroethylene polymer contains an inorganic filler, there is a problem that it is difficult to obtain a molded product having sufficient properties. Such a problem is remarkable when another component (various components described in paragraph 0019 of Patent Document 1 and the like) is further blended with the dispersion liquid. According to the studies by the present inventors, the state stability of the dispersion is remarkable when a polymer having an ester bond, an imide bond or an amide bond or a compound P composed of a precursor of such a polymer is blended as another component. It has decreased. Specifically, due to the foaming of the dispersion liquid and the decrease in dispersibility, a molded product having excellent surface smoothness could not be obtained.

As a result of diligent studies, the present inventors have excellent state stability if the dispersion contains a tetrafluoroethylene polymer, an inorganic filler, the compound P, a liquid amide, and a predetermined liquid compound. It was found that it is difficult to foam and that a molded product with excellent surface smoothness can be formed. It was also found that such a molded product has a high degree of physical properties of each component.
An object of the present invention is to provide such a dispersion liquid and a method for producing the same, and a method for producing a laminate having a polymer layer formed from the dispersion liquid.

The present invention has the following aspects.
[1] Compound P composed of a tetrafluoroethylene polymer powder, an inorganic filler, a polymer having an ester bond, an imide bond or an amide bond, or a precursor of such a polymer, a liquid amide, a ketone, an ester, and an aromatic. A dispersion containing at least one liquid compound selected from the group consisting of hydrocarbons.
[2] The dispersion liquid of [1], wherein the content of the liquid amide is larger than the content of the liquid compound.
[3] The dispersion liquid of [1] or [2], wherein the content of the tetrafluoroethylene polymer is 5% by mass or more.
[4] The dispersion according to any one of [1] to [3], wherein the ratio of the content of the inorganic filler to the content of the tetrafluoroethylene polymer by mass is 0.5 to 2.0.
[5] The dispersion according to any one of [1] to [4], wherein the ratio of the content of the compound P to the content of the tetrafluoroethylene polymer by mass is 0.4 or less.

[6] The dispersion liquid according to any one of [1] to [5], wherein the inorganic filler is an inorganic filler containing silica.
[7] The dispersion liquid according to any one of [1] to [6], wherein the inorganic filler is a hollow inorganic filler.
[8] The dispersion liquid according to any one of [1] to [7], wherein the average particle size of the inorganic filler is 1 μm or less.
[9] The liquid amide is N-methyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, N, N-dimethylacetamide or dimethylformamide. The dispersion liquid according to any one of [1] to [8], wherein the liquid compound is cyclohexanone, cyclopentanone, γ-butyrolactone or toluene.
[10] The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing a unit based on perfluoro (alkyl vinyl ether) or a unit based on hexafluoropropene, or a polytetrafluoroethylene having a number average molecular weight of 200,000 or less. The dispersion liquid according to any one of [1] to [9].

[11] The dispersion liquid according to any one of [1] to [10], wherein the compound P is an aromatic polyester, an aromatic polyimide, an aromatic polyamic acid or a maleimide compound.
[12] The dispersion liquid according to any one of [1] to [11], wherein the compound P is a liquid crystal aromatic polyester, a thermoplastic aromatic polyimide, or a thermosetting maleimide compound.
[13] The dispersion liquid according to any one of [1] to [12], further containing a surfactant.
[14] The method for producing a dispersion according to any one of [1] to [13], wherein a liquid composition containing the compound P, the inorganic filler, the liquid amide and the liquid compound, and the tetrafluoroethylene system. A method for producing a dispersion, which comprises mixing a polymer powder and a liquid composition containing the liquid amide to obtain the dispersion.
[15] The dispersion liquid according to any one of [1] to [13] is applied to the surface of the base material and heated to form a polymer layer containing the tetrafluoroethylene-based polymer, which is composed of the base material. A method for producing a laminate, which comprises obtaining a laminate having a base material layer and the polymer layer.

According to the present invention, a dispersion liquid containing a tetrafluoroethylene polymer powder, an inorganic filler, and the compound P and having excellent state stability can be obtained.

The following terms have the following meanings.
The "average particle size (D50)" is a volume-based cumulative 50% diameter of the object (powder or filler) determined by the laser diffraction / scattering method. That is, the particle size distribution of the object is measured by the laser diffraction / scattering method, the cumulative curve is obtained with the total volume of the group of particles of the object as 100%, and the particles at the point where the cumulative volume is 50% on the cumulative curve. The diameter.
“D90” is the volume-based cumulative 90% diameter of the object, measured in the same manner.
The "specific surface area" is a value obtained by analyzing an inorganic filler by a gas adsorption method (BET method).
The “melting temperature (melting point)” is the temperature corresponding to the maximum value of the melting peak of the polymer measured by the differential scanning calorimetry (DSC) method.
The "glass transition point" is a value measured by analyzing a polymer by a dynamic viscoelasticity measurement (DMA) method.
A "unit" in a polymer is an atomic group formed directly from one molecule of a monomer by a polymerization reaction, and an atom obtained by processing the polymer obtained by the polymerization reaction by a predetermined method to convert a part of its structure. It may be a group. The unit based on monomer A contained in the polymer is also simply referred to as "monomer A unit".

The dispersion liquid of the present invention (hereinafter, also referred to as “the present dispersion liquid”) is a powder of a tetrafluoroethylene-based polymer (hereinafter, also referred to as “F polymer”) (hereinafter, also referred to as “F powder”). At least one liquid selected from the group consisting of an inorganic filler, a polymer having an ester bond, an imide bond or an amide bond, or a compound P consisting of a precursor of such a polymer, a liquid amide, and a ketone, an ester and an aromatic hydrocarbon. Includes with compounds. Hereinafter, the liquid compound selected from the group consisting of ketones, esters and aromatic hydrocarbons is also referred to as "liquid compound Q".
The F polymer and the compound P are different compounds, and the compound P is a compound different from both the liquid amide and the liquid compound Q.
This dispersion is a dispersion in which F powder and an inorganic filler are dispersed in a liquid dispersion medium containing a liquid amide and a liquid compound Q, and compound P is highly dissolved.
This dispersion is excellent in state stability. From this dispersion, it is easy to form a molded product having a high degree of physical characteristics of each of the F polymer, the inorganic filler and the compound P (hereinafter, also referred to as “three components”). The reason is not always clear, but it can be considered as follows.

The liquid amide has high wettability in all three components and functions as a good dispersion medium or solvent for the three components in the dispersion liquid. Due to this function, in the dispersion liquid containing the liquid amide, the liquid amide and the F polymer having a low surface tension are highly wetted, so that the apparent concentration of the other two components, particularly the compound P, is considered to increase. As a result, it is considered that the interaction of the compound P is excessively enhanced, the viscosity of the dispersion liquid is increased, and the aggregation and sedimentation of the three components are induced, so that the state stability of the entire dispersion liquid is rather lowered.
This dispersion further contains the liquid compound Q in addition to the above liquid amide. While the liquid compound Q has the same solubility in the compound P as the liquid amide, the wettability to the inorganic filler and the F polymer, particularly the F polymer, is lower than that of the liquid amide. Therefore, if the dispersion liquid further contains the liquid compound Q, it is considered that it selectively functions as a solvent for the compound P and stabilizes the state.

That is, it is considered that this dispersion is excellent in state stability such as foaming and homogeneity because the dispersibility or solubility of the three components is balanced by the inclusion of the two liquid dispersion media. As a result, it is considered that a molded product having excellent surface smoothness and having a high degree of physical characteristics of the three components can be easily formed from the dispersion liquid.

The F powder in this dispersion contains an F polymer. The content of the F polymer in the F powder is preferably 80% by mass or more, more preferably 100% by mass.
Other components that can be contained in the F powder include polymers and inorganic substances different from the F polymer. Examples of the polymer different from the F polymer include aromatic polyester, polyamide-imide, thermoplastic polyimide, polyphenylene ether, and polyphenylene oxide. Examples of the inorganic substance include silicon oxide (silica), metal oxides (beryllium oxide, cerium oxide, alumina, soda alumina, magnesium oxide, zinc oxide, titanium oxide, etc.), boron nitride, and magnesium metasilicate (steatite).
The F powder containing the other component preferably has a core-shell structure having the F polymer as a core and the other component in the shell, or a core-shell structure having the F polymer as the shell and the other component in the core. .. Such F powder is obtained, for example, by coalescing (collision, agglomeration, etc.) the powder of the F polymer and the powder of the other components.

The D50 of the F powder is preferably 10 μm or less, more preferably 6 μm or less, and even more preferably 4 μm or less. The D50 of the F powder is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 1 μm or more. Further, the D90 of the F powder is more preferably 10 μm or less.
The content of the F polymer in this dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 25% by mass or more. The content of the F polymer is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. Due to the above-mentioned mechanism of action, the dispersion liquid tends to be excellent in state stability even when the content of the F polymer is high.

The F polymer in this dispersion is a polymer containing a unit (TFE unit) based on tetrafluoroethylene (TFE).
Examples of the F polymer include polytetrafluoroethylene having a number average molecular weight of 200,000 or less (hereinafter, also referred to as “low molecular weight PTFE”), and a unit (PAVE unit) or hexafluoro based on perfluoro (alkyl vinyl ether) (PAVE). Polymers containing units based on propene (HFP) (HFP units) are preferred. The latter F polymer may contain both PAVE and HFP units.

The number average molecular weight of the low molecular weight PTFE is preferably 100,000 or less, more preferably 50,000 or less. The number average molecular weight of the PTFE is preferably 10,000 or more. The number average molecular weight is a value calculated based on the following equation (1).
Mn = 2.1 × 10 ¹⁰ × ΔHc- ^5.16 ... (1)
In the formula (1), Mn indicates the number average molecular weight of low molecular weight PTFE, and ΔHc indicates the amount of heat of crystallization (cal / g) of low molecular weight PTFE measured by differential scanning calorimetry.
As the PAVE, CF ₂ = CFOCF ₃ , CF ₂ = CFOCF ₂ CF ₃ or CF ₂ = CFOCF ₂ CF ₂ CF ₃ (PPVE) is preferable, and PPVE is more preferable.

The melting temperature (melting point) of the F polymer is preferably 200 ° C. or higher, more preferably 260 ° C. or higher, further preferably 280 to 325 ° C., and particularly preferably 285 to 320 ° C.
The glass transition point of the F polymer is preferably 75 to 125 ° C, more preferably 80 to 100 ° C.
The F polymer preferably has a polar functional group. The polar functional group may be contained in a unit in the F polymer, or may be contained in the terminal group of the main chain of the polymer. Examples of the latter aspect include an F polymer having a polar functional group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer having a polar functional group obtained by plasma-treating or ionizing the F polymer. Be done.

The polar functional group is preferably a hydroxyl group-containing group or a carbonyl group-containing group, and a carbonyl group-containing group is more preferable from the viewpoint of enhancing the state stability of the dispersion.
The hydroxyl group-containing group is preferably an alcoholic hydroxyl group-containing group, preferably -CF ₂ CH ₂ OH or -C (CF ₃ ) ₂ OH.
The carbonyl group-containing group is a group containing a carbonyl group (> C (O)), and is a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC (O) NH ₂ ), and an acid anhydride residue. A group (-C (O) OC (O)-), an imide residue (-C (O) NHC (O)-etc.) or a carbonate group (-OC (O) O-) is preferred.
The number of carbonyl group-containing groups in the F polymer is preferably 10 to 5000, more preferably 100 to 3000, and even more preferably 50 to 1500, per ^{1 × 10 6 carbon atoms in the main chain.} The number of carbonyl group-containing groups in the F polymer can be quantified by the composition of the polymer or the method described in International Publication No. 2020/145133.

As the F polymer, a polymer containing TFE units and PAVE units, containing 1.5 to 5.0 mol% of PAVE units with respect to all units, and having a melting temperature of 285 to 320 ° C. is preferable, and TFE units, PAVE units and A polymer having a polar functional group (1) containing a unit based on a monomer having a polar functional group, and containing 2.0 to 5.0 mol% of PAVE units with respect to all units including TFE units and PAVE units. The polymer (2) having no polar functional group is more preferable.
Not only is the powder excellent in state stability, these F polymers are more likely to be more densely and uniformly distributed in the molded product formed from the present dispersion. Furthermore, microspherulites are likely to be formed in the molded product, and adhesion with other components is likely to be enhanced. As a result, it is easier to obtain a molded product having a high degree of physical characteristics of the three components.

As the polymer (1), the TFE unit is 90 to 98 mol%, the PAVE unit is 1.5 to 9.97 mol%, and the unit based on the monomer having a polar functional group is 0.01 to 3 with respect to all the units. It is preferable to contain each in mol%.
Further, as the monomer having a polar functional group, itaconic anhydride, citraconic anhydride and 5-norbornene-2,3-dicarboxylic acid anhydride (also known as hymic anhydride; hereinafter, also referred to as “NAH”) are preferable.
Specific examples of the polymer (1) include the polymers described in International Publication No. 2018/16644.

The polymer (2) is composed of only TFE units and PAVE units, and contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units with respect to all the units. Is preferable.
The content of PAVE units in the polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, based on all the units.
The fact that the polymer (2) does not have polar functional groups means that the number of polar functional groups contained in the polymer is less than 500 with respect to ^{1 × 10 6 carbon atoms constituting the polymer main chain.} Means that The number of the polar functional groups is preferably 100 or less, more preferably less than 50. The lower limit of the number of polar functional groups is usually 0.
The polymer (2) may be produced by using a polymerization initiator, a chain transfer agent or the like that does not generate a polar functional group as the terminal group of the polymer chain, and is an F polymer having a polar functional group (derived from the polymerization initiator). An F polymer having a polar functional group at the terminal group of the main chain of the polymer) may be fluorinated to produce the polymer. Examples of the fluorination treatment method include a method using fluorine gas (see JP-A-2019-194314, etc.).

The content of the inorganic filler in this dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more. The content of the inorganic filler is preferably 40% by mass or less, more preferably 35% by mass or less, and further preferably 30% by mass or less.
The ratio (mass ratio) of the content of the inorganic filler to the content of the F polymer in the present dispersion is preferably 0.5 or more, more preferably 0.8 or more, still more preferably 1.0 or more. The above ratio is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.6 or less.
Due to the above-mentioned action mechanism, the dispersion liquid tends to be excellent in state stability even when the inorganic filler is contained in a high concentration.

As the inorganic filler, a nitride filler and an inorganic oxide filler are preferable, and boron nitride filler, beryllia filler (verylium oxide filler), silicate filler (silica filler, wollastonite filler, talc filler), and talc filler. Metal oxide (cerium oxide, aluminum oxide, magnesium oxide, zinc oxide, titanium oxide, etc.) fillers are more preferable. Such an inorganic filler makes it easy to balance the interaction between the components and further improves the state stability of the dispersion liquid. In addition, the physical properties of the molded product are likely to be remarkably exhibited.
The inorganic filler preferably contains silica from the viewpoint of further improving the state stability of the dispersion liquid.
The content of silica in the inorganic filler containing silica is preferably 50% by mass or more, more preferably 75% by mass or more, still more preferably 99% by mass or more. The upper limit of the silica content is 100% by mass.

It is preferable that at least a part of the surface of the inorganic filler is surface-treated. Examples of the surface treatment agent used for such surface treatment include polyhydric alcohols (trimethylolethane, pentaeristol, propylene glycol, etc.), saturated fatty acids (stearic acid, lauric acid, etc.), esters thereof, alkanolamines, amines (trimethylamine, etc.). (Triethylamine, etc.), paraffin wax, silane coupling agent, silicone, polysiloxane, etc.
Silane coupling agents include 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane or 3-isocyanate. Propyltriethoxysilane is preferred.

The average particle size of the inorganic filler is preferably 20 μm or less, more preferably 1 μm or less, further preferably 0.8 μm or less, and particularly preferably 0.6 μm or less. The average particle size is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more. Even when the dispersion liquid contains such an inorganic filler, which has a large specific surface area and is easily wetted, it tends to be excellent in state stability due to the above-mentioned action mechanism. When the inorganic filler is a hollow inorganic filler, the average particle size described later is preferable.
Specific examples of such inorganic fillers include zinc oxide ("FINEX" manufactured by Sakai Chemical Industry Co., Ltd.) surface-treated with an ester such as silica filler ("Admafine" series manufactured by Admatex Co., Ltd.) and propylene glycol dicaprate. Series, etc.), spherical molten silica (Denka's "SFP" series, etc.), coated with polyhydric alcohol and inorganic substances (Ishihara Sangyo's "Typake" series, etc.), and surface-treated with alkylsilane. Type Titanium oxide ("JMT" series manufactured by Teika), talc filler ("SG" series manufactured by Nippon Tarku, etc.), Steatite filler ("BST" series manufactured by Nippon Tarku, etc.), Boron nitride filler ("BST" series, etc.) Examples include the "UHP" series manufactured by Showa Denko Co., Ltd. and the "Denka Boron Night Ride" series ("GP" and "HGP" grades) manufactured by Denka Co., Ltd.).

The shape of the inorganic filler may be granular, needle-like (fibrous), or plate-like. Specific shapes of the inorganic filler include spherical, scaly, layered, leafy, apricot kernel, columnar, chicken crown, equiaxed, leafy, mica, block, flat, wedge, rosette, and mesh. Shape and prismatic shape.
The shape of the inorganic filler is preferably hollow. Even when the dispersion liquid contains such an inorganic filler, which has a large specific surface area and is easily wetted, it tends to be excellent in state stability due to the above-mentioned action mechanism.

The average particle size of the hollow inorganic filler is preferably 0.01 μm or more, more preferably 0.1 μm or more. The average particle size is preferably 100 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. In such a case, in the molded product molded from the present dispersion, the inorganic fillers are likely to be in contact with each other and filled, and the molded product is likely to be excellent in electrical insulation.
The specific surface area of the inorganic filler (BET method) is preferably 10 ~ 250m ² / g, more preferably 40 ~ 100m ² / g.
Due to the above-mentioned action mechanism, the present dispersion tends to be excellent in state stability even when it contains an inorganic filler having a large average particle size and a large specific surface area.

The average pore diameter of the pores of the hollow inorganic filler is preferably 10 to 1000 nm, more preferably 50 to 100 nm. For the average pore diameter, the pore diameters of a plurality of pores (100) are obtained by direct observation with a scanning electron microscope (SEM) or the like, and the average value is taken as the average pore diameter. In the case of irregularly shaped holes, the maximum diameter of the holes is the hole diameter.
The apparent specific gravity of the hollow inorganic filler is preferably 100 g / L or less, more preferably 30 to 60 g / L, from the viewpoint of sufficiently increasing the porosity. The apparent specific gravity of the hollow inorganic filler is obtained from the mass and volume of the inorganic filler when it is charged into a graduated cylinder (capacity: 250 mL).
The bulk density of the hollow inorganic filler is preferably from 5 g / cm ³ or less, preferably from 1 g / cm ³ or less. The lower limit of the bulk density is preferably 0.1 or more.
As the hollow inorganic filler, a hollow silica filler is preferable. Specific examples of hollow silica fillers include hydrophobic AEROSIL series "RX200" (manufactured by Nippon Aerosil), E-SPHERES series (manufactured by Taiheiyo Cement), Sirinax series (manufactured by Nittetsu Mining Co., Ltd.), and eco-cosfier series. (Manufactured by Emerson & Cumming) and the like.

Compound P in this dispersion is a polymer having an ester bond, an imide bond or an amide bond, or a precursor of such a polymer. The polymer precursor refers to an oligomer or a non-polymeric compound that becomes a polymer by polymerization, cross-linking, or the like.
As the compound P, a compound P having an imide bond or an amide bond is preferable, a polymer having a unit containing an imide bond, a polymer having a unit containing an amide bond, and an N-substituted maleimide structure, an imide succinate structure or a phthalimide structure. A precursor having the above is more preferable. Further, a compound having a polyimide, polyamideimide, polyamic acid, and N-substituted maleimide structure (maleimide compound) is preferable, and a polyimide and a maleimide compound are particularly preferable.
The polymer-like compound P is a polymer different from the F polymer. When the compound P is a polymer precursor, the dispersion liquid preferably contains a polymerization initiator for polymerizing the polymer precursor and a curing agent for curing the polymer precursor together with the polymer precursor.

Compound P is preferably aromatic. When the aromatic compound P is formed into a molded product, the aromatic rings having high flatness are likely to be in a laminated state, so that the mechanical strength and heat resistance of the molded product are likely to be improved. Further, since the aromatic compound has an absorption property for ultraviolet rays having a wavelength of 355 nm, which is common in UV lasers, the UV processability of the obtained molded product is likely to be further improved.
The polyimide is preferably an aromatic polyimide, and more preferably a thermoplastic aromatic polyimide.
If the compound P is a thermoplastic aromatic polyimide, the plasticity of the compound P further improves the uniformity of the aromatic polyimide in the molded product formed from the present dispersion, and a dense molded product is likely to be formed. As a result, the physical properties of the aromatic polyimide are likely to be highly expressed in the molded product, and the adhesion of the molded product is also likely to be excellent.

As the aromatic polyimide, a semi-aromatic polyimide in which one of the tetracarboxylic dianhydride and the diamine has an aromatic ring, or a total aromatic polyimide in which both have an aromatic ring is more preferable.
Specific examples of aromatic polyimides include "Neoprim" series (manufactured by Mitsubishi Gas Chemical Company), "Spixeria" series (manufactured by Somar), "Q-PILON" series (manufactured by PI Technology Research Institute), and "WINGO" series (manufactured by PI Technology Co., Ltd.). Wingo Technology Co., Ltd.), "Toimide" series (T & K TOKA Co., Ltd.), "KPI-MX" series (Kawamura Sangyo Co., Ltd.).

If the compound P is a maleimide compound, the maleimide compound is likely to be uniformly and densely distributed in the molded product formed from the present dispersion, the physical properties of the maleimide compound are likely to be highly expressed, and the electrical characteristics and difficulties of the molded product are difficult. Flammability and adhesion are more likely to be improved. In this case, the dispersion further contains a component (radical polymerization initiator, imidazole-based curing agent, cationic curing agent, other copolymerizable crosslinkable monomer, etc.) that further promotes the reaction of the maleimide compound. Is preferable.
As the maleimide compound, a bismaleimide compound is more preferable. The bismaleimide compound may have an N-substituted maleimide structure only in the terminal group, or may have an N-substituted maleimide structure in both the terminal group and the side chain.

Maleimide compounds include 4,4'-diphenylmethane bismaleimide, phenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane. Examples thereof include bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and 1,6'-bismaleimide- (2,2,4-trimethyl) hexane.
The maleimide compound is a reaction product of a diamine such as diamine or a diamine having an alicyclic structure and a tetracarboxylic acid dianhydride having an aromatic ring, and maleic anhydride is added to a polyimide having an amino group as a terminal group. Examples thereof include a bismaleimide compound obtained by reaction.
These maleimide compounds are commercially available as BMI series manufactured by DESIGNER MOLECULES Inc.

As the compound P having an ester bond, an aromatic polyester is preferable, and a liquid crystal aromatic polyester (liquid crystal polyester) is more preferable. The aromatic polyester also includes an aromatic polyester amide having an amide bond further introduced, and an aromatic polyester having an isocyanate-derived bond such as an imide bond, a carbonate bond, a carbodiimide bond, or an isocyanurate bond introduced therein. Will be done.
Specific examples of the liquid crystal polyester include dicarboxylic acids (terephthalic acid, isophthalic acid, diphenyl ether-4,4'-dicarboxylic acid, acetic anhydride, etc.), dihydroxy compounds (4,4'-biphenol, etc.), aromatic hydroxycarboxylic acids (4,4'-biphenol, etc.). 4-Hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, etc.), polymers such as aromatic diamine, aromatic hydroxyamine, aromatic aminocarboxylic acid, 4-hydroxybenzoic acid And 6-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid and acetaminophen, 4-hydroxybenzoic acid, terephthalic acid and 4,4'-biphenol. Examples thereof include a reaction product of 2-hydroxy-6-naphthoic acid, 4,4'-dihydroxybiphenyl, terephthalic acid and 2,6-naphthalenedicarboxylic acid.
The liquid crystal polyester may be a solvent-soluble type or a solvent-insoluble type.
The melting point of the liquid crystal polyester is preferably 280 to 340 ° C.

The content of compound P in this dispersion is preferably 0.01% by mass or more, more preferably 0.1% by mass or more. The content of compound P is preferably 5% by mass or less, more preferably 1% by mass or less.
The ratio (mass ratio) of the content of compound P to the content of F polymer in this dispersion by mass is preferably 0.001 or more, more preferably 0.01 or more. The above ratio is preferably 0.4 or less, more preferably 0.2 or less. Even when compound P is contained in such a ratio, the present dispersion is excellent in state stability due to the above-mentioned action mechanism.

The liquid amide in this dispersion is a liquid compound inert at 25 ° C. that functions as a dispersion medium or solvent for the three components. The liquid amide is preferably an amide that is compatible with the liquid compound Q.
The liquid amide may be used as a mixture of two or more of them.
The boiling point of the liquid amide is preferably 125 to 250 ° C. In this case, when the molded product is formed from the present dispersion, the molded product tends to have excellent homogeneity.
As the liquid amide, N-methyl-2-pyrrolidone (NMP), 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide are used from the viewpoint of ease of wetting with the three components. , N, N-dimethylacetamide and dimethylformamide are preferred, with NMP being more preferred.
The content of the liquid amide in this dispersion is preferably 40% by mass or more, more preferably 50% by mass or more. The content of the liquid amide is preferably 90% by mass or less, more preferably 80% by mass or less.

The liquid compound Q in this dispersion is a liquid compound selected from the group consisting of ketones, esters and aromatic hydrocarbons, and is an inactive liquid compound at 25 ° C. The liquid compound Q is preferably a compound that is compatible with the liquid amide. Further, the liquid compound Q may be used in combination of two or more thereof.
As the liquid compound Q, 4-methyl-2-pentanone, cyclohexanone, tetrahydrofuran, toluene, xylene, γ-butyrolactone, cyclopentanone, butyl acetate and methyl isopropyl ketone are preferable from the viewpoint of enhancing the state stability of the dispersion. , Cyclohexanone, cyclopentanone, γ-butyrolactone and toluene are more preferred. Further, cyclohexanone, cyclopentanone and γ-butyrolactone are more preferable as the liquid compound Q when the compound P is polyimide, and toluene is more preferable as the liquid compound Q when the compound P is a maleimide compound.

The content of the liquid compound Q in this dispersion is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more. The content of the liquid compound Q is preferably 40% by mass or less, more preferably 35% by mass or less, and further preferably 30% by mass or less.
The content of the liquid amide in this dispersion is preferably higher than the content of the liquid compound Q. In this case, the above-mentioned mechanism of action balances the affinity between the three components (particularly between the inorganic filler and the compound P) without lowering the dispersibility of the three components (particularly the F polymer) itself. , It is easy to improve the state stability of this dispersion.
The ratio (mass ratio) of the content of the liquid compound Q to the content of the liquid amide by mass is preferably 0.8 or less, more preferably 0.5 or less. The above ratio is preferably 0.1 or more, more preferably 0.2 or more. When the ratio of the two is within such a range, the above-mentioned mechanism of action allows the three components (particularly, the inorganic filler and the compound P) to be separated from each other without lowering the dispersibility of the three components (particularly the F polymer) itself. It is easy to improve the state stability of this dispersion by balancing the affinity between them.

The dispersion liquid preferably further contains a surfactant from the viewpoint of improving state stability and handleability.
The surfactant is preferably nonionic.
The hydrophilic moiety of the surfactant preferably has an oxyalkylene group or an alcoholic hydroxyl group.
The oxyalkylene group may be composed of one kind or two or more kinds. In the latter case, different types of oxyalkylene groups may be arranged in a random manner or in a block shape.
As the oxyalkylene group, an oxyethylene group is preferable.
The hydrophobic moiety of the surfactant preferably has an acetylene group, a polysiloxane group, a perfluoroalkyl group or a perfluoroalkenyl group. In other words, the surfactant is preferably an acetylene-based surfactant, a silicone-based surfactant or a fluorine-based surfactant, and more preferably a silicone-based surfactant.

As the fluorine-based surfactant, a fluorine-based surfactant having a hydroxyl group (particularly an alcoholic hydroxyl group) or an oxyalkylene group and a perfluoroalkyl group or a perfluoroalkenyl group is preferable.
Specific examples of surfactants include "Futergent" series (manufactured by Neos), "Surflon" series (manufactured by AGC Seimi Chemical Co., Ltd.), "Megafuck" series (manufactured by DIC), and "Unidyne" series (manufactured by Daikin Industries). (Made by), "BYK-347", "BYK-349", "BYK-378", "BYK-3450", "BYK-3451", "BYK-3455", "BYK-3456" (Big Chemie Japan shares) (Manufactured by a company), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.).
The content of the surfactant in this dispersion is preferably 1 to 15% by mass. In this case, the affinity between the components is enhanced, and the state stability of the dispersion liquid is likely to be further improved.

The viscosity of this dispersion is preferably 50 mPa · s or more, more preferably 100 mPa · s or more. The viscosity of this dispersion is preferably 10,000 mPa · s or less, more preferably 1000 mPa · s or less, and even more preferably 800 mPa · s or less.
The thixotropy ratio of this dispersion is preferably 1.0 or more. The thixotropy of the dispersion is preferably 3.0 or less, more preferably 2.0 or less.
This dispersion is easy to adjust to a viscosity or thixotropic property in such a range, and is excellent in handleability.

The dispersion may further contain a resin (polymer) different from the F polymer or compound P. The other resin may be a thermosetting resin or a thermoplastic resin.
Examples of other resins include epoxy resins, urethane resins, elastomers, polyphenylene ethers, polyphenylene oxides, and fluoropolymers other than F polymers.
In addition to the above-mentioned components, this dispersion contains a thioxogenic agent, a defoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weather resistant agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, and an increase. It may contain additives such as whitening agents, colorants, conductive agents, mold release agents, surface treatment agents, viscosity modifiers, and flame retardants.

In this dispersion, a liquid composition (hereinafter, also referred to as “liquid composition N”) is prepared by mixing the compound P dissolved in the liquid compound Q, the liquid amide, and the inorganic filler, and the liquid composition N is combined with the liquid composition N. It is preferably produced by a method of mixing a liquid composition containing F powder and a liquid amide (hereinafter, also referred to as “liquid composition F”) (hereinafter, also referred to as “method 1”). In the preparation of the liquid composition N, the liquid compound Q may be separately mixed to adjust its state stability.
The content of the compound P in the liquid composition N is preferably 0.01% by mass or more, more preferably 0.1% by mass or more. The content is preferably 10% by mass or less.
The content of the inorganic filler in the liquid composition N is preferably 5% by mass or more, more preferably 10% by mass or more. The content is preferably 50% by mass or less.

The content of the liquid amide in the liquid composition N is preferably 50% by mass or more, more preferably 60% by mass or more. The content is preferably 90% by mass or less.
The content of the liquid compound Q in the liquid composition N is preferably 1% by mass or more, more preferably 5% by mass or more. The content is preferably 40% by mass or less.
The liquid composition N preferably further contains a dispersant. The mode of the dispersant in the liquid composition N is the same as that of the dispersant in the present dispersion, including the preferred mode.
The liquid composition N may further contain a resin (polymer) different from the F polymer and the compound P, and other components other than the inorganic filler.

The content of the F polymer in the liquid composition F is preferably 5% by mass or more, more preferably 10% by mass or more. The content is preferably 60% by mass or less.
The content of the liquid amide in the liquid composition F is preferably 50% by mass or more, more preferably 60% by mass or more. The content is preferably 90% by mass or less.
The liquid composition F preferably further contains a dispersant. The mode of the dispersant in the liquid composition F is the same as that of the dispersant in the present dispersion, including the preferred mode.
The liquid composition F may further contain a resin (polymer) different from the F polymer and the compound P, and other components.

This dispersion can be used for forming a molded product having a high degree of physical properties of three components.
A laminate having the base material layer composed of the base material and the polymer layer can be obtained by a method of applying the dispersion liquid to the surface of the base material and heating to form a polymer layer containing the F polymer. ..
This polymer layer is a layer containing an F polymer and an inorganic filler, and compound P or a reaction product thereof, and is a layer in which each component is uniformly and densely distributed.
Examples of the base material include metal base materials (metal foils such as copper, nickel, aluminum, titanium, and alloys thereof), resin films (polyimide, polyarylate, polysulfone, polyallylsulfone, polyamide, polyetheramide, polyphenylene sulfide, etc.). Examples thereof include films such as polyallyl ether ketone, polyamideimide, liquid polyester, and liquid polyester amide), and prepreg (a precursor of a fiber-reinforced resin base material).

The dispersion is applied by spray method, roll coating method, spin coating method, gravure coating method, micro gravure coating method, gravure offset method, knife coating method, kiss coating method, bar coating method, die coating method, fountain Mayer bar method, etc. It can be done by the slot die coating method.
The heating after the coating film is preferably carried out by heating by removing the liquid dispersion medium (liquid amide, liquid compound Q) and drying, and heating by melting and firing the F polymer. The former heating temperature is preferably 120 ° C to 200 ° C. The latter heating temperature is preferably 250 ° C. to 400 ° C., more preferably 300 to 380 ° C. When the compound P is a polymer precursor, the latter is usually heated to become a polymer.
Heating can be performed by a method using an oven, a method using a ventilation drying oven, or a method of irradiating heat rays such as infrared rays.

The thickness of the polymer layer formed is preferably 0.1 to 150 μm. Specifically, when the base material is a metal foil, the thickness of the polymer layer is preferably 1 to 30 μm. When the base material is a resin film, the thickness of the polymer layer is preferably 1 to 150 μm, more preferably 10 to 50 μm.
The polymer layer may be formed on only one surface of the base material or on both sides of the base material. In the former, a base material layer and a laminate having a polymer layer on one surface of the base material layer are obtained, and in the latter, a laminate having a polymer layer on both the surfaces of the base material layer and the base material layer. Is obtained. Since the latter laminate is less likely to warp, it is excellent in handleability during processing.

Specific examples of the laminate include a metal foil layer, a metal-clad laminate having a polymer layer on at least one surface of the metal foil layer, a polyimide film layer, and a polymer layer on both surfaces of the polyimide film layer. Multilayer film can be mentioned.
These laminates are suitable as a printed base material or the like because they have a high degree of physical characteristics of three components and are particularly excellent in electrical characteristics. Specifically, such a laminate can be used in the production of a flexible printed base material or a rigid printed base material.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.
1. 1. Preparation of each ingredient [F polymer / F powder]
Powder 1: Contains 97.9 mol%, 0.1 mol%, and 2.0 mol% of TFE units, NAH units, and PPVE units in this order, and has 1000 ^{carbonyl groups per 1 × 10 6 main chain carbon atoms.} Powder (D50: 2.1 μm) made of polymer (melting temperature: 300 ° C., F polymer 1)
Powder 2: Polymer 2 containing 98.7 mol% and 1.3 mol% of TFE units and PPVE units in this order and ^{having 40 carbonyl groups per 1 × 10 6} main chain carbon atoms (melting temperature: 305 ° C., Powder consisting of F polymer 2) (D50: 1.8 μm)

[Inorganic filler]
Filler 1: Hollow silica filler (D50: 0.5 μm, bulk specific density: 0.10 g / cm ³ )
Filler 2: Crushed titanium oxide filler (D50: 2 to 6 μm, bulk specific density: 0.25 to 0.75 g / cm ³ )
[Compound P]
PI1: Thermoplastic aromatic polyimide BM1: Bismaleimide compound (“BMI-3000” manufactured by DESIGNER MOLECULES). In addition, BM1 further contains a heat-sensitive radical polymerization initiator for thermosetting it.

[Liquid dispersion medium]
NMP: N-methyl-2-pyrrolidone CHN: Cyclohexanone Tol: Toluene [Surfactant]
Surfactant 1: CH ₂ = C (CH ₃ ) C (O) OCH ₂ CH ₂ (CF ₂ ) ₆ F and CH ₂ = C (CH ₃ ) C (O) (OCH ₂ CH ₂ ) ₂₃ OH Copolymer

2. Production example of dispersion liquid (Example 1)
First, the varnish in which PI1 was dissolved in CHN and NMP were put into the pot, then the zirconia balls were put into the pot, and the pot was rolled at 150 rpm for 1 hour. Subsequently, the surfactant 1 was added and the pot was rolled at 150 rpm for 1 hour, and further, the filler 1 was added and the pot was rolled at 150 rpm for 1 hour to prepare a liquid composition N1.
Powder 1, surfactant 1 and NMP were put into another pot, and zirconia balls were put into the pot. Then, the pot was rolled at 150 rpm for 1 hour to prepare a liquid composition F1.

In still another pot, the liquid compositions of both were charged, and zirconia balls were charged. Then, the pot was rolled at 150 rpm for 1 hour to add powder 1 (8 parts by mass), filler 1 (12 parts by mass), PI1 (0.1 parts by mass), and surfactant 1 (1 part by mass). , NMP (49 parts by mass) and CHN (27 parts by mass) were contained in a dispersion liquid 1 (viscosity: 700 mPa · s).
The ratio of the content of the liquid compound Q to the content of the liquid amide in the dispersion 1 by mass was 0.6, and the ratio of the content of F polymer to the content of PI1 by mass was 0.01. The ratio of the content of F polymer to the content of inorganic filler by mass was 1.5.

(Examples 2 to 7)
Dispersions 2 to 7 were obtained in the same manner as in Example 1 except that the type and amount of the liquid dispersion medium were changed as shown in Table 1 below.

3. 3. Production Example of Laminated Body (Copper-clad Laminated Body) A wet film was formed by applying the dispersion liquid 1 to the surface of a long copper foil (thickness: 18 μm) using a bar coater. Next, the copper foil on which the wet film was formed was passed through a drying oven at 120 ° C. for 5 minutes and dried by heating to obtain a dry film. Then, the dry film was heated at 380 ° C. for 3 minutes in an oven under a nitrogen gas atmosphere. As a result, a laminate 1 having a copper foil and a polymer layer (thickness: 5 μm) containing F polymer 1, PI1 and filler 1 was produced.
Laminates 2 to 4 were produced in the same manner as the laminate 1 except that the dispersion 1 was changed to each of the dispersions 2 to 7.

4. Evaluation 4-1. State stability of the dispersions For each dispersion, the state immediately after preparation and the state after storage in a container at 25 ° C. were visually confirmed, and the state stability was evaluated according to the following criteria.
[Evaluation criteria]
〇: There is little foaming immediately after preparation, and it is well dispersed even after storage.
Δ: Immediately after preparation, although it foams, it is dispersed. After storage, agglomerates adhere to the wall surface.
X: Immediately after preparation, it foams and immediately becomes mousse-like. After storage, a large amount of agglomerates have settled.

4-2. Surface Smoothness of Laminates The surface smoothness of each polymer layer of the laminate was visually confirmed, and the surface smoothness was evaluated according to the following criteria.
[Evaluation criteria]
〇: The entire surface of the polymer layer is smooth.
Δ: The edge of the polymer layer is raised and the central part is recessed.
X: The edges of the polymer layer are raised, the central portion is recessed, and unevenness due to lack of polymer or inorganic filler is also confirmed.
The evaluation results are summarized in Table 2 below.

4-3. Electrical characteristics and dimensional stability of the laminate For each of the laminates 1, 3 and 7, the copper foil of the laminate was removed by etching with an aqueous ferric chloride solution to prepare a single polymer layer, and SPDR (split post dielectric) was prepared. The dielectric constant and the dielectric loss tangent (measurement frequency: 10 GHz) of the polymer layer were measured by the body resonance method.
Further, for each of the laminated bodies 1, 3 and 7, a 180 mm square test piece is cut out, and the test piece line is in the range of 25 ° C. or higher and 260 ° C. or lower according to the measurement method specified in JIS C 6471: 1995. The coefficient of expansion was measured.
The results of each are summarized in Table 3 below.

This dispersion has excellent state stability and can be used for producing molded products (films, impregnated materials such as prepregs, laminated plates, etc.) having highly physical properties based on F-polymers, inorganic fillers and compound P. The molded product of the present invention is useful as an antenna part, a printed substrate, an aircraft part, an automobile part, a sports tool, a food industry product, a paint, a cosmetic, and the like. ), Electrical insulation tape, insulation tape for oil drilling, material for printed substrate, separation membrane (precision filtration membrane, ultrafiltration membrane, reverse osmosis membrane, ion exchange membrane, dialysis membrane, gas separation membrane, etc.), electrode binder ( Lithium secondary batteries, fuel cells, etc.), copy rolls, furniture, automobile dashboards, covers for home appliances, sliding members (load bearings, sliding shafts, valves, bearings, gears, cams, belt conveyors, food transport It is useful as a material for bearings, etc.), tools (shovels, shavings, cuttings, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, dies, toilet bowls, and container covering materials.
The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2019-234714 filed on December 25, 2019 are cited here and incorporated as disclosure of the specification of the present invention. Is.

Claims

From compound P, which consists of a tetrafluoroethylene polymer powder, an inorganic filler, a polymer having an ester bond, an imide bond or an amide bond, or a precursor of such a polymer, a liquid amide, a ketone, an ester, and an aromatic hydrocarbon. A dispersion containing at least one liquid compound selected from the group.
The dispersion according to claim 1, wherein the content of the liquid amide is larger than the content of the liquid compound.
The dispersion liquid according to claim 1 or 2, wherein the content of the tetrafluoroethylene polymer is 5% by mass or more.
The dispersion according to any one of claims 1 to 3, wherein the ratio of the content of the inorganic filler to the content of the tetrafluoroethylene polymer by mass is 0.5 to 2.0.
The dispersion according to any one of claims 1 to 4, wherein the ratio of the content of the compound P to the content of the tetrafluoroethylene polymer by mass is 0.4 or less.
The dispersion liquid according to any one of claims 1 to 5, wherein the inorganic filler is an inorganic filler containing silica.
The dispersion liquid according to any one of claims 1 to 6, wherein the inorganic filler is a hollow inorganic filler.
The dispersion liquid according to any one of claims 1 to 7, wherein the average particle size of the inorganic filler is 1 μm or less.
The liquid amide is N-methyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, N, N-dimethylacetamide or dimethylformamide. The dispersion according to any one of claims 1 to 8, wherein the liquid compound is cyclohexanone, cyclopentanone, γ-butyrolactone or toluene.
Claim 1 The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing a unit based on perfluoro (alkyl vinyl ether) or a unit based on hexafluoropropene, or a polytetrafluoroethylene having a number average molecular weight of 200,000 or less. 9. The dispersion according to any one of 9.
The dispersion according to any one of claims 1 to 10, wherein the compound P is an aromatic polyester, an aromatic polyimide, an aromatic polyamic acid or a maleimide compound.
The dispersion according to any one of claims 1 to 11, wherein the compound P is a liquid crystal aromatic polyester, a thermoplastic aromatic polyimide, or a thermosetting maleimide compound.
The dispersion liquid according to any one of claims 1 to 12, further containing a surfactant.
The method for producing a dispersion according to any one of claims 1 to 13, wherein a liquid composition containing the compound P, the inorganic filler, the liquid amide, and the liquid compound, and the tetrafluoroethylene-based polymer. A method for producing a dispersion liquid, wherein the powder and the liquid composition containing the liquid amide are mixed to obtain the dispersion liquid.
The dispersion liquid according to any one of claims 1 to 13 is applied to the surface of a base material and heated to form a polymer layer containing the tetrafluoroethylene-based polymer, which is composed of the base material. A method for producing a laminate, which comprises obtaining a laminate having a base material layer and the polymer layer.