JP2022163625A - Method for producing modified dispersion liquid and dispersion liquid - Google Patents

Abstract

To provide a method for producing a modified dispersion liquid containing tetrafluoroethylene-based polymer particles, inorganic particles, a liquid dispersion medium, and a non-fluorine-based leveling agent, and having excellent dispersion stability and film-forming properties, and also to provide a dispersion liquid.SOLUTION: A method is for producing a modified dispersion liquid including tetrafluoroethylene-based polymer particles, inorganic particles and a liquid dispersion medium. A non-fluorine-based leveling agent is added to a dispersion liquid in which a ratio of the inorganic particles in the total amount is 20 to 60 mass% to decrease a surface tension of the dispersion liquid so as to obtain a modified dispersion liquid.SELECTED DRAWING: None

Description

The present invention relates to a modified dispersion comprising particles of a tetrafluoroethylene-based polymer and an amount of inorganic particles and a process for making the dispersion.

Tetrafluoroethylene polymers such as polytetrafluoroethylene (PTFE) have excellent physical properties such as electrical properties, water and oil repellency, chemical resistance, and heat resistance, and are used in various industrial applications such as printed circuit boards. there is A dispersion containing particles of a tetrafluoroethylene-based polymer is known as a coating agent used for imparting the above physical properties to the substrate surface.
Such a dispersion liquid is attracting attention as a material excellent in electric properties such as a low dielectric constant and a low dielectric loss tangent for forming a dielectric layer of a printed circuit board corresponding to frequencies in a high frequency band.

In order to improve the storage stability and dispersion stability of such a dispersion, Patent Document 1 proposes blending a fluorine-based surfactant and ceramics into the dispersion. Each of Patent Documents 2 and 3 proposes blending a fluorine-based surfactant and a predetermined polyvinyl alcohol into a dispersion.

JP 2016-194017 A JP 2020-186351 A JP 2017-210549 A

A tetrafluoroethylene-based polymer is excellent in electrical properties and the like, but a dispersion liquid containing its particles is poor in dispersion stability, miscibility with other materials, and adhesiveness when a molding is formed. When a fluorosurfactant is blended as a dispersion component, the dispersion stability of the dispersion is improved, but the film-forming properties of the dispersion are likely to be lowered. Specifically, it becomes difficult to form a thick molded product, and the uniformity, workability and adhesiveness of the molded product tend to deteriorate. The present inventors have found that this tendency is remarkable when a large amount of inorganic particles are added to the dispersion as a dispersion component for improving the physical properties of the molded product.

As a result of intensive studies, the present inventors have found that if a non-fluorine-based leveling agent is added to a dispersion containing tetrafluoroethylene polymer particles and inorganic particles to reduce the surface tension for modification, a large amount of It has been found that dispersion liquids containing inorganic particles are also excellent in dispersion stability and film-forming properties. Further, the inventors have found that such a modified dispersion can be used to form thick moldings that are excellent in uniformity, workability, adhesion to other materials, and low linear expansion.
An object of the present invention is to provide a thick film containing particles of a tetrafluoroethylene polymer, inorganic particles, a liquid compound, and a non-fluorine leveling agent, and having excellent uniformity, workability, adhesion to other materials, and low linear expansion. Methods of making modified dispersions capable of forming moldings and such dispersions are provided.

The present invention has the following aspects.
<1> A non-fluorine-based leveling agent is added to a dispersion containing tetrafluoroethylene polymer particles, inorganic particles, and a liquid dispersion medium, wherein the proportion of the inorganic particles in the total amount is 20 to 60% by mass, A method for producing a modified dispersion, wherein the modified dispersion is obtained by reducing the surface tension of the dispersion.
<2> The production method of <1>, wherein the tetrafluoroethylene-based polymer particles include heat-melting tetrafluoroethylene-based polymer particles and non-heat-melting tetrafluoroethylene-based polymer particles.
<3> The production method of <1> or <2>, wherein the tetrafluoroethylene-based polymer has a melting temperature of 200 to 325°C.
<4> The production method according to any one of <1> to <3>, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having a carbonyl group-containing group or a hydroxyl group-containing group.
<5> The production method according to any one of <1> to <4>, wherein the inorganic particles are silica particles.
<6> Any one of <1> to <5>, wherein the non-fluorine leveling agent is at least one selected from the group consisting of (meth)acrylic leveling agents, silicone leveling agents and alcohol alkoxylates. Production method.
<7> The production method according to any one of <1> to <6>, wherein the liquid dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters.
<8> The production method according to any one of <1> to <7>, wherein the difference between the surface tension of the modified dispersion and the surface tension of the dispersion is 1 mN/m or less.
<9> The production method according to any one of <1> to <8>, wherein the dispersion further contains an aromatic polymer.
<10> The production method according to any one of <1> to <9>, wherein the dispersion further contains a nonionic surfactant.
<11> The modified dispersion obtained by the production method of any one of <1> to <10> is applied to the surface of a substrate and heated to contain the tetrafluoroethylene-based polymer and the inorganic particles. A method for producing a laminate, comprising forming a polymer layer to obtain a laminate having a substrate layer composed of the substrate and the polymer layer.
<12> The manufacturing method of <11>, wherein the polymer layer has a thickness of 25 μm or more.
<13> The method according to <11> or <12>, wherein the surface of the substrate has a ten-point average roughness of 0.1 μm or less.
<14> At least one non-fluorinated compound selected from the group consisting of tetrafluoroethylene polymer particles, inorganic particles, liquid dispersion medium, (meth)acrylic leveling agent, silicone leveling agent and alcohol alkoxylate and a leveling agent, wherein the proportion of the tetrafluoroethylene-based polymer particles and the proportion of the inorganic particles in the total amount are 5 to 40% by mass and 20 to 60% by mass in this order.
<15> The modified dispersion of <14>, wherein the liquid dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters.

According to the present invention, it is possible to obtain a modified dispersion having a high content of inorganic particles, which contains particles of a tetrafluoroethylene polymer, inorganic particles, a liquid dispersion medium, and a non-fluorine leveling agent. The modified dispersion is excellent in dispersion stability and film-forming properties, and can form thick moldings with excellent uniformity, workability, adhesion to other materials, and low linear expansion.

The following terms have the following meanings.
A "tetrafluoroethylene-based polymer" is a polymer containing units based on tetrafluoroethylene, and hereinafter also simply referred to as an "F polymer".
"Average particle diameter (D50)" is the volume-based cumulative 50% diameter of the object (particles) determined by the laser diffraction/scattering method. That is, the particle size distribution is measured by a laser diffraction/scattering method, a cumulative curve is obtained with the total volume of the group of objects as 100%, and the particle diameter at the cumulative volume of 50% on the cumulative curve.
The D50 of the object is obtained by dispersing the object in water and analyzing it by a laser diffraction/scattering method using a laser diffraction/scattering particle size distribution analyzer (LA-920 measuring instrument manufactured by Horiba, Ltd.). .
"Average particle size (D90)" is the cumulative volume particle size of the object, and is the volume-based cumulative 90% diameter of the object determined in the same manner as "D50".
"Polymer melting temperature" is the temperature corresponding to the maximum melting peak of the polymer as measured by differential scanning calorimetry (DSC).
"Hot-melt resin (polymer)" has a melt flow rate of 1 to 1000 g/10 minutes at a temperature higher than the melting temperature of the resin (polymer) by 20°C or more under a load of 49N. It means a fluid resin (polymer).
"Non-meltable resin (polymer)" means a non-melt-flowable resin (polymer) at which there is no temperature at which the melt flow rate is 1 to 1000 g/10 minutes under a load of 49N.
"Polymer glass transition point (Tg)" is a value measured by analyzing a polymer by dynamic viscoelasticity measurement (DMA).
“Viscosity” is the viscosity of a dispersion or liquid composition measured at 25° C. and 30 rpm using a Brookfield viscometer. The measurement is repeated 3 times, and the average value of the 3 measurements is taken.
_The "thixotropic ratio" is a value calculated by dividing the viscosity _η1 of a dispersion or liquid composition measured at a rotation speed of 30 rpm by the viscosity η2 measured at a rotation speed of 60 rpm. be. Each viscosity measurement is repeated three times, and the average value of the three measurements is taken.
A "unit" in a polymer means an atomic group based on the monomer formed by polymerization of the monomer. The units may be units directly formed by a polymerization reaction, or may be units in which some of said units have been converted to another structure by treatment of the polymer. Hereinafter, units based on monomer a are also simply referred to as "monomer a units".

The production method of the present invention (hereinafter also referred to as "this method") comprises particles of a tetrafluoroethylene polymer (F polymer) (hereinafter also referred to as "F particles"), inorganic particles and a liquid dispersion medium. A non-fluorine-based leveling agent is added to a dispersion containing 20 to 60% by mass of inorganic particles in the total amount (hereinafter also referred to as "original dispersion") to reduce the surface tension of the original dispersion. to obtain a modified dispersion. The modified dispersion in this method is a dispersion containing F particles, inorganic particles, a liquid compound and a non-fluorine leveling agent.
The modified dispersion obtained by this method has excellent dispersion stability and film-forming properties, and can form thick moldings with excellent uniformity, workability, adhesion to other materials, and low linear expansion. . Although the reason is not necessarily clear, it is considered as follows.

When the surface tension of the dispersion is high, the F polymer, which has a low surface tension, is less likely to interact with the inorganic particles and the liquid dispersion medium, and the F particles tend to aggregate. On the other hand, when the surface tension of the dispersion is low, when the dispersion is applied to the base material to form a molded product, the dispersion tends to spread thinly, making it difficult to obtain a thick and uniform molded product. These tendencies tend to become more pronounced when the proportion of inorganic particles in the dispersion increases.
In this method, a non-fluorine leveling agent is added to an original dispersion containing F particles, inorganic particles and a liquid dispersion medium. As a result, the surface tension of the modified dispersion can be moderately lowered while suppressing aggregation of the F particles.

Moreover, the addition of a leveling agent improves the rheology (viscosity, thixotropic ratio, etc.) of the modified dispersion, and makes it easier to suppress sedimentation of the F particles and the inorganic particles. Furthermore, the non-fluorine-based leveling agent also acts as a binder, making it easier to improve the physical properties of molded articles formed from the modified dispersion. Specifically, the non-fluorine-based leveling agent promotes close contact between the F polymer and the inorganic particles in the molded article, thereby facilitating the improvement of the low linear expansion property of the molded article. In addition, the non-fluorine-based leveling agent is unevenly distributed on the surface of the molded product, improving the adhesiveness of the surface of the molded product, and easily suppressing powder falling off of F particles and inorganic particles.
As a result, according to this method, a modified dispersion excellent in handling properties such as dispersion stability and film-forming properties can be obtained, and further, uniformity, workability, adhesion to other materials, and low linear expansion can be obtained. It is thought that a thick molded product with excellent properties was formed.

The F polymer in the present invention is a polymer containing units (hereinafter also referred to as "TFE units") based on tetrafluoroethylene (hereinafter also referred to as "TFE").
The F polymer may be hot meltable or non-hot meltable.
When the F polymer is heat-meltable, its melting temperature is preferably 200° C. or higher, more preferably 240° C. or higher, and even more preferably 260° C. or higher. The melting temperature of the F polymer is preferably 325° C. or lower, more preferably 320° C. or lower. The melting temperature of the F polymer is particularly preferably 200-320°C.

The glass transition point of F polymer is preferably 50° C. or higher, more preferably 75° C. or higher. The glass transition point of the F polymer is preferably 150° C. or lower, more preferably 125° C. or lower.
The surface tension of the F polymer is preferably 16-26 mN/m, more preferably 16-20 mN/m. The surface tension of the F polymer can be measured by placing a droplet of a wetting index reagent (manufactured by Wako Pure Chemical Industries, Ltd.) on a flat plate made of the F polymer.
The fluorine content of the F polymer is preferably 70% by mass or more, more preferably 72 to 76% by mass. The F polymer with a high fluorine content is excellent in physical properties such as electrical properties, but on the other hand, it has a low surface tension, and the dispersion stability in the original dispersion tends to decrease. The dispersion stability of such F polymer is likely to be improved.

F polymers include polytetrafluoroethylene (PTFE), polymers containing TFE units and ethylene-based units, polymers containing TFE units and propylene-based units, based on TFE units and perfluoro(alkyl vinyl ether) (PAVE). polymer (PFA) containing units (PAVE units), polymer (FEP) containing TFE units and units based on hexafluoropropylene, polymers containing TFE units and units based on fluoroalkylethylene, TFE units and chlorotrifluoro ethylene-based units, preferably PFA or FEP, more preferably PFA. The polymer may further contain units based on other comonomers.
PAVE is preferably CF ₂ =CFOCF ₃ , CF ₂ =CFOCF ₂ CF ₃ or CF ₂ =CFOCF ₂ CF ₂ CF ₃ (hereinafter also referred to as “PPVE”), more preferably PPVE.

PTFE may be non-heat-fusible PTFE or heat-fusible PTFE.
The F polymer preferably has oxygen-containing polar groups. In this case, it becomes easy to form microspherulites at the molecular assembly level, the wettability of the F particles is improved, and the effects of the present invention described above are likely to be exhibited to a high degree.
The oxygen-containing polar 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 F polymer. As the latter mode, F polymer having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, chain transfer agent, etc., F polymer having an oxygen-containing polar group obtained by plasma treatment or ionizing radiation treatment of F polymer polymers. The oxygen-containing polar group is preferably a hydroxyl group-containing group, a carbonyl group-containing group and a phosphono group-containing group, more preferably a hydroxyl group-containing group and a carbonyl group-containing group from the viewpoint of dispersion stability of the modified dispersion, and a carbonyl group-containing group is more preferred.

The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF ₂ CH ₂ OH or -C(CF ₃ ) ₂ OH.
A carbonyl group-containing group is a group containing a carbonyl group (>C(O)), and includes a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH ₂ ), 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, and an acid anhydride residue is more preferred. In this case, the F particles are likely to interact with the inorganic particles and the liquid dispersion medium, and the modified dispersion tends to be excellent in liquid physical properties such as dispersion stability.

The F polymer is preferably a polymer having carbonyl group-containing groups comprising TFE units and PAVE units, more preferably a polymer comprising units based on monomers having TFE units, PAVE units and carbonyl group-containing groups. , in this order, 90 to 99 mol %, 0.5 to 9.97 mol %, and 0.01 to 3 mol % of these units relative to all units. The presence of a carbonyl group-containing group is preferable from the viewpoint of further improving the affinity of the F polymer with inorganic particles and liquid dispersion medium and the adhesion with other materials.

When the F polymer has a carbonyl group-containing group, the number of carbonyl group-containing groups in the F polymer is preferably 10 to 5000, more preferably 100 to 3000, more preferably 800 per 1 × 10 ⁶ carbon atoms in the main chain. ~1500 is more preferred. 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 WO2020/145133.
The monomer having a carbonyl group-containing group is preferably itaconic anhydride, citraconic anhydride or 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"). Specific examples of such polymers include those described in WO2018/16644.

D50 of the F particles in the present invention is preferably 0.1 to 25 μm. D50 of the F particles is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. D50 of the F particles is preferably 0.2 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. In this range of D50, the fluidity and dispersion stability of the F particles tend to be good.
From the viewpoint of dispersion stability, the specific surface area of F particles is preferably 1 to 25 m ² /g, more preferably 1 to 8 m ² /g.

One type of F particles may be used, or two or more types may be used. When two types of F particles are used, the F particles preferably contain heat-melting F polymer particles and non-heat-melting F polymer particles, and the F polymer having a melting temperature of 200 to 320° C. (preferably more preferably contains particles of a polymer having an oxygen-containing polar group containing TFE units and PAVE units described above) and particles of non-thermally fusible PTFE.
In this case, when the liquid properties are modified by adding a non-fluorine-based leveling agent to the original dispersion, it is thought that the non-thermally fusible F polymer is moderately fibrillated while maintaining its physical properties. Inorganic particles are easily carried in a molded article formed from the material, and the strength of the molded article is likely to be further improved.

In this case, the ratio of the former particles to the total of the former particles and the latter particles is preferably 50% by mass or less, more preferably 25% by mass or less. Moreover, the ratio in this case is preferably 0.1% by mass or more, more preferably 1% by mass or more.
In this case, the D50 of the F polymer particles having a melting temperature of 200 to 320° C. is 0.1 to 1 μm, and the D50 of the non-thermally fusible PTFE particles is 0.1 to 1 μm. is 200 to 320° C., the D50 of the particles of the F polymer is 1 to 4 μm, and the D50 of the non-heat-fusible PTFE particles is 0.1 to 1 μm.

The F particles may contain a resin or inorganic particles other than the F polymer, but preferably contain the F polymer as a main component. The content of the F polymer in the F powder is preferably 80% by mass or more, more preferably 100% by mass.
Resins other than the F polymer include heat-resistant resins such as aromatic polyesters, polyamideimides, (thermoplastic) polyimides, polyphenylene ethers, polyphenylene oxides, and maleimides. Inorganic substances contained in inorganic particles include silicon oxide (silica), metal oxides (beryllium oxide, cerium oxide, alumina, soda alumina, magnesium oxide, zinc oxide, titanium oxide, etc.), boron nitride, magnesium metasilicate (steatite ). At least part of the surface of the inorganic particles may be surface-treated.

The F particles containing a resin other than the F polymer or inorganic particles have a core-shell structure in which the F polymer is the core and the shell is the resin or inorganic particles other than the F polymer, or the F polymer is the shell and the particles other than the F polymer It may have a core-shell structure with a resin or inorganic particles in the core. Such F particles are obtained, for example, by coalescing (colliding, aggregating, etc.) particles of the F polymer and particles of a resin other than the F polymer or inorganic particles.
The content of the F particles in the modified dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, relative to the total amount of the modified dispersion. The content of the F particles is preferably 40% by mass or less, more preferably 30% by mass or less, relative to the total amount of the modified dispersion.

The inorganic particles in the present invention may contain components other than inorganic compounds, but preferably contain inorganic compounds as the main component. The content of the inorganic compound in the inorganic particles is preferably 80% by mass or more, more preferably 100% by mass.
One type of inorganic particles may be used alone, or two or more types may be used in combination.
The shape of the inorganic particles may be spherical, acicular (fibrous), or plate-like, preferably plate-like or spherical, more preferably spherical, and substantially spherical. More preferred. In addition, the substantially spherical inorganic particles are inorganic particles in which the proportion of spherical particles having a ratio of the short axis to the long axis of 0.7 or more is 95% or more when observed with a scanning electron microscope (SEM). means particles. In this case, the inorganic particles and the F particles are likely to interact with each other, and the modified dispersion tends to be excellent in physical properties such as dispersion stability. In addition, a molded article formed from the modified dispersion tends to be excellent in electrical properties and low linear expansion.

Specific shapes of the inorganic particles include spherical, scale-like, layer-like, leaf-like, apricot kernel-like, columnar, crest-like, equiaxed, leaf-like, mica-like, block-like, tabular, wedge-like, rosette-like, and network. shape and prismatic shape.
The inorganic particles are preferably carbon particles, nitride particles and inorganic oxide particles, carbon fiber particles, boron nitride particles, aluminum nitride particles, beryllia particles, silicate particles (silica particles, wollastonite particles, talc particles), and metal oxide particles (cerium oxide, aluminum oxide, magnesium oxide, zinc oxide, titanium oxide, etc.) are more preferable, and the dispersion stability of the modified dispersion and the electrical properties and Boron nitride particles and silica particles are more preferred, and silica particles are particularly preferred, from the viewpoint of increasing low linear expansion properties.

D50 of the inorganic particles is preferably 20 μm or less, more preferably 10 μm or less. D50 is preferably 0.01 μm or more, more preferably 0.1 μm or more. The ratio of D50 of inorganic particles to D50 of F particles is preferably 0.01 or more, more preferably 0.1 or more. The above ratio is preferably 20 or less, more preferably 10 or less.
The specific surface area of the inorganic particles is preferably 1-20 m ² /g.
From the viewpoint of improving the wettability of the inorganic particles, at least a part of the surface of the inorganic particles contains a silane coupling agent (3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3 -glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.).

Preferable specific examples of inorganic particles include silica particles ("Admafine (registered trademark)" series manufactured by Admatechs), zinc oxide surface-treated with an ester such as propylene glycol dicaprate (Sakai Chemical Industry Co., Ltd. "FINEX (registered trademark)" series manufactured by Denka), spherical fused silica ("SFP (registered trademark)" series manufactured by Denka, etc.), titanium oxide coated with polyhydric alcohol and inorganic substances (manufactured by Ishihara Sangyo Co., Ltd. "Tipake (registered trademark)" series, etc.), rutile-type titanium oxide surface-treated with alkylsilane ("JMT (registered trademark)" series, manufactured by Tayca Corporation, etc.), hollow silica particles ("E -SPHERES" series, Nittetsu Mining Co., Ltd.'s "Sirinax" series, Emerson & Cumming Co.'s "Ecocospear" series, etc.), talc particles (Nippon Talc Co., Ltd.'s "SG" series, etc.), steatite particles ( Nippon Talc "BST" series, etc.), boron nitride particles (Showa Denko "UHP" series, Denka "Denka Boron Nitride" series ("GP", "HGP" grades), etc.) mentioned.

The proportion of the inorganic particles in the total amount of the modified dispersion is 20-60% by weight. The proportion of inorganic particles is preferably 30% by mass or more. The proportion of inorganic particles is preferably 50% by mass or less.
In the modified dispersion, the ratio of the content of the inorganic particles to the content of the F particles is preferably 0.8 or more, more preferably greater than 1. The above ratio is preferably 3 or less, more preferably 2 or less. In this case, the modified dispersion tends to be excellent in dispersion stability and film-forming properties, and it is easy to form a molded product excellent in uniformity, adhesiveness, low linear expansion, and electrical properties.

A liquid dispersion medium in the present invention means a compound that is liquid at 25° C. under atmospheric pressure. The liquid dispersion medium is preferably at least one selected from the group consisting of hydrocarbons, water, alcohols, amides, ketones and esters, and more preferably at least one selected from the group consisting of water, amides, ketones and esters.
The boiling point of the liquid dispersion medium is preferably 50 to 240°C. One type of the liquid dispersion medium may be used alone, or two or more types may be used in combination.
Alcohols include methanol, ethanol, isopropanol, glycol.

Amides include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy- N,N-dimethylpropanamide, N,N-diethylformamide, hexamethylphosphorictriamide, 1,3-dimethyl-2-imidazolidinone and the like.
Ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, cycloheptanone.

Esters include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, γ-butyrolactone, γ- Valerolactone can be mentioned.
Preferred specific examples of the liquid dispersion medium include water, N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone and cyclopentanone, and the dispersion stability, film-forming properties and handling properties of the modified dispersion are improved. Water is preferable from the point of view.
The content of the liquid dispersion medium in the modified dispersion is preferably 20 to 70% by mass, more preferably 30 to 50% by mass. Within this range, the liquid physical properties such as dispersion stability of the modified dispersion are likely to be improved.

The non-fluorine-based leveling agent in the present invention is a leveling agent having no fluorine atom, and is preferably a (meth)acrylic leveling agent, a silicone-based leveling agent or an alcohol alkoxylate. And from the viewpoint of the effect of improving film-forming properties, a (meth)acrylic leveling agent is more preferable.
A (meth)acrylic leveling agent means a leveling agent having a structure derived from (meth)acrylic acid or (meth)acrylate. The (meth)acrylic leveling agent may be a polymer of (meth)acrylic acid or (meth)acrylate, or may be a non-polymeric compound having a (meth)acryloyloxy group as its residue. .

A silicone leveling agent means a leveling agent having a siloxane structure.
The silicone leveling agent may be a polymer having a polysiloxane structure, or a compound having a siloxane structure such as a hydrolyzable silyl group.
(Meth)acrylic acid is a generic term for methacrylic acid and acrylic acid, (meth)acrylate is a generic term for methacrylate and acrylate, and (meth)acryloyloxy group is a generic term for methacryloyloxy group and acryloyloxy group.

The (meth)acrylic leveling agent is at least one selected from the group consisting of (meth)acrylic acid, polyether-modified (meth)acrylate, silicone-modified (meth)acrylate and polyether/silicone-modified (meth)acrylate ( It is preferably a polymer of meth)acrylates or a non-polymeric compound having residues of one of the above (meth)acrylates.
The polyether/silicone-modified (meth)acrylate means a (meth)acrylate modified with polyether and silicone.

Silicone leveling agents include polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified acrylic group-containing polydimethylsiloxane, polyester-modified acrylic group-containing polydimethylsiloxane, and polymethylalkyl. Siloxanes or epoxy-modified polydimethylsiloxanes are preferred.
1 type may be used for a non-fluorine-type leveling agent, and 2 or more types may be used for it.
The average molecular weight of the non-fluorine leveling agent is preferably 100-200,000. In this case, the modified dispersion tends to be excellent in dispersion stability and film-forming properties.

Specific examples of non-fluorinated leveling agents include "BYK-325", "BYK-345", "BYK-346", "BYK-347", "BYK-349", "BYK-UV3500", "BYK- 380 N”, “BYK-381”, “BYK-399”, “BYK-3440”, “BYK-3550”, “BYK-3560”, “BYK-3565”, “BYK-3566”, “BYK-SILCLEAN 3700", "BYK-SILCLEAN 3701", "BYK-SILCLEAN 3720", "BYK-DYNWET 800 N", "BYKETOL-AQ", "BYKETOL-WS" (manufactured by BYK-Chemie Japan Co., Ltd.), "Polyflow WS", "Polyflow WS-30", and "Polyflow WS-314" (manufactured by Kyoeisha Chemical Co., Ltd.).
The ratio of the non-fluorine leveling agent to the total amount of the modified dispersion is preferably 0.1 to 15% by mass, more preferably 1 to 5% by mass. Within this range, the liquid physical properties such as dispersion stability of the modified dispersion are likely to be improved.

The original dispersion in this method can be produced by mixing F particles, inorganic particles and a liquid dispersion medium.
The mixing method includes a method of adding the F particles and the inorganic particles to the liquid dispersion medium at once and mixing, a method of sequentially adding the F particles and the inorganic particles to the liquid dispersion medium and mixing them, and a method of adding the F particles and the inorganic particles. A method of mixing to form a powder mixture and further mixing with a liquid dispersion medium, a method of premixing the F particles and the liquid dispersion medium, and premixing the inorganic particles and the liquid dispersion medium, respectively, and further mixing the resulting two mixtures. A preferred method is to mix F particles and inorganic particles to form a powder mixture, which is then mixed with a liquid dispersion medium.

The mixing method for preparing the original dispersion may be either a batch method or a continuous method.
In addition, the device used for mixing includes a propeller blade, a turbine blade, a paddle blade, a stirring device equipped with blades (stirring blades) such as shell-shaped blades (stirring blades) on a single shaft or multiple shafts, a Henschel mixer, a pressure kneader, a Banbury mixer or Agitation by a planetary mixer; ball mill, attritor, basket mill, sand mill, sand grinder, dyno mill (bead mill using grinding media such as glass beads or zirconium oxide beads), dispermat, SC mill, spike mill, agitator mill, etc. Mixing by a dispersing machine using media; Mixing using a dispersing machine that does not use media, such as a high-pressure homogenizer such as a microfluidizer, a nanomizer, or an ultimizer, an ultrasonic homogenizer, a dissolver, a disper, or a high-speed impeller dispersing machine. .

Among them, the apparatus used for mixing is preferably a Henschel mixer, a pressure kneader, a Banbury mixer or a planetary mixer, more preferably a planetary mixer.
The planetary mixer has two stirring blades that rotate and revolve with each other, and has a structure for stirring and mixing and kneading the mixture in the stirring vessel. Therefore, there is little dead space in the agitation tank that the agitating blades do not reach, and the load on the agitating blades is reduced, so that the contents can be mixed to a high degree.
When the original dispersion further contains optional additive components such as an aromatic polymer and a nonionic surfactant, which will be described later, they can be mixed at any stage. The mixing method and mixing apparatus include the same mixing method and mixing apparatus as described above.

In this method, a modified dispersion is obtained by adding a non-fluorine leveling agent to the original dispersion to lower its surface tension.
The non-fluorine leveling agent may be added directly to the original dispersion or may be added to the original dispersion as a mixture with a liquid dispersion medium. The liquid dispersion medium may be the same as or different from the liquid dispersion medium contained in the original dispersion.
Examples of the mixing method and mixing apparatus for mixing the original dispersion and the non-fluorine-based leveling agent include the mixing method and mixing apparatus for preparing the above-mentioned original dispersion.

The surface tension of the modified dispersion in the present invention is lower than that of the original dispersion.
The difference between the surface tension of the modified dispersion and the surface tension of the original dispersion is preferably 0.1 mN/m or more, more preferably 0.2 mN/m or more. The difference is preferably 1 mN/m or less, more preferably 0.5 mN/m or less. In this case, the surface tension of the original dispersion moderately decreases, the aggregation of the F particles is easily eliminated, and the modified dispersion tends to be excellent in dispersion stability and film-forming properties.

Preferably, the modified dispersion further comprises an aromatic polymer.
Aromatic polymers may be thermoplastic or thermoset. Also, the aromatic polymer may be dissolved in the modified dispersion, or may be dispersed without being dissolved. An aromatic polymer may be included in the modified dispersion as a precursor thereof.
Aromatic polymers are preferably aromatic imide-based polymers, aromatic polyimides, aromatic polyimide precursors (polyamic acid or salts thereof), aromatic polyamideimides, aromatic polyamideimide precursors, aromatic polyetherimides or aromatic Polyetherimide precursors are preferred, and aromatic polyimide precursors or aromatic polyamideimides are more preferred. These aromatic polymers may be modified aromatic polymers further introduced with acidic groups such as carboxylic acid groups and phenolic hydroxyl groups.
When the modified dispersion contains water as a liquid dispersion medium, the aromatic polymer is preferably water-soluble and is a water-soluble aromatic polyamideimide precursor or a water-soluble aromatic polyimide precursor. is more preferred.

A water-soluble aromatic polymer can be prepared by adjusting its acid value and the basicity of the modified dispersion. For example, when the aromatic polymer is an aromatic polyamic acid, it can be prepared by reacting the aromatic polyamic acid with ammonia water or an organic amine to obtain a polyamic acid salt.
Specifically, the aromatic polymer in this case preferably has an acid value of 20 to 100 mg/KOH, more preferably 35 to 70 mgKOH/g. In this case, the pH of the modified dispersion is preferably 5-10, more preferably 7-9.
If the acid value of the aromatic polymer and the pH of the modified dispersion are within the above ranges, not only the dispersion stability of the modified dispersion is improved, but also the aromatic The group polymer is highly dispersed, and it is easy to improve the physical properties (ultraviolet absorption, flexibility, adhesion, etc.) of the molded product.
Specific examples of aromatic polymers include “Ultem 1000F3SP” (manufactured by SABIC), “HPC-1000” and “HPC-2100D” (all of which are manufactured by Showa Denko Materials).

The original dispersion in the present invention preferably further contains a nonionic surfactant.
The hydrophilic portion of the nonionic surfactant preferably has an oxyalkylene group or an alcoholic hydroxyl group.
The oxyalkylene group may be composed of one type, or may be composed of two or more types. In the latter case, different types of oxyalkylene groups may be arranged randomly or in blocks. In addition, the oxyalkylene group is preferably an oxyethylene group.
The hydrophobic portion of the nonionic surfactant preferably has an acetylene group, polysiloxane group, perfluoroalkyl group or perfluoroalkenyl group. In other words, the surfactant is preferably a polyoxyalkylene alkyl ether, an acetylenic surfactant, a silicone surfactant or a fluorosurfactant, more preferably a silicone surfactant.
As the silicone surfactant, an organopolysiloxane having a polyoxyalkylene structure as a hydrophilic group and a polydimethylsiloxane structure as a hydrophobic group is preferred. When a silicone-based surfactant is included, the polyoxyalkylene alkyl ether and the silicone-based surfactant may be used in combination from the viewpoint of improving the long-term storage stability of the modified dispersion.

Specific examples of nonionic surfactants include the "Ftergent" series (manufactured by Neos Co., Ltd. Ftergent is a registered trademark), the "Surflon" series (manufactured by AGC Seimi Chemical Co., Ltd. Surflon is a registered trademark), and the "Megafac" series. (Megafac manufactured by DIC Corporation is a registered trademark), "Unidyne" series (Unidyne manufactured by Daikin Industries, Ltd. is a registered trademark), "BYK-347", "BYK-349", "BYK-378", "BYK-3450" ”, “BYK-3451”, “BYK-3455”, “BYK-3456” (manufactured by BYK-Chemie Japan Co., Ltd.), “KF-6011”, “KF-6043” (manufactured by Shin-Etsu Chemical Co., Ltd.), “ Tergitol" series (manufactured by Dow Chemical Co., Ltd., "Tergitol TMN-100X", etc.), "Lutensol T08", "Lutensol XL70", "Lutensol XL80", "Lutensol XL90", "Lutensol XP80", "Lutensol M5" (above , manufactured by BASF), "Newcol 1308FA", "Newcol 1310" (manufactured by Nippon Nyukazai Co., Ltd.), "LEOCOL TDN-90-80", "LEOCOL SC-90" (manufactured by Lion Specialty Chemicals made).
When the modified dispersion contains a nonionic surfactant, the content of the nonionic surfactant in the modified dispersion is preferably 0.1 to 15% by mass, more preferably 1 to 10% by mass.

When the modified dispersion contains water as a liquid dispersion medium, the pH of the modified dispersion is preferably 5 to 10, more preferably 7 to 9, from the viewpoint of long-term storage.
The modified dispersion may further contain a pH adjusting agent or pH buffering agent. .
pH adjusters include amines, ammonia, and citric acid.
pH buffers include tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium bicarbonate, ammonium carbonate and ammonium acetate.
The step of adding the pH adjusting agent or pH buffering agent may be before or during mixing.

The modified dispersion may be subjected to a defoaming treatment. Degassing is preferably carried out using a rotation-revolution stirrer.
In addition to the above components, the modified dispersion contains a thixotropic agent, a viscosity modifier, an antifoaming agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightener, a coloring agent, Additives such as agents, conductive agents, release agents, surface treatment agents, flame retardants, preservatives, antifungal agents, organic fillers, etc. may be further included.

The viscosity of the modified dispersion is preferably 10 mPa·s or more, more preferably 50 mPa·s or more, and even more preferably 100 mPa·s or more. The viscosity of the modified dispersion is preferably 10000 mPa·s or less, more preferably 3000 mPa·s or less, and even more preferably 1000 mPa·s or less. In this case, the modified dispersion tends to be excellent in dispersion stability, film-forming properties, and the like.
The thixotropic ratio of the modified dispersion is preferably 1.0 or more. The thixotropic ratio of the modified dispersion is preferably 3.0 or less, more preferably 2.0 or less. In this case, the modified dispersion is excellent in liquid physical properties such as dispersion stability, and can easily form a denser molded product.

The dispersed layer ratio of the modified dispersion is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. Since the modified dispersion is excellent in dispersion stability, the dispersion layer ratio tends to fall within the above range.
Here, the dispersion layer ratio is the total height of the dispersion in the screw tube before and after standing when the dispersion (18 mL) is put in a screw tube (inner volume: 30 mL) and allowed to stand at 25 ° C. for 14 days. and the height of the sedimentation layer (dispersion layer), the value is calculated by the following formula. If no sedimentation layer is observed after standing and there is no change in the state, the dispersion layer ratio is assumed to be 100% on the assumption that there is no change in the height of the dispersion as a whole.
Dispersed layer ratio (%) = (height of sedimentation layer) / (height of entire dispersion) x 100

The solid content of the modified dispersion is preferably 30% by mass or more, more preferably 40% by mass or more. From the viewpoint of dispersion stability, the solid content of the modified dispersion is preferably 80% by mass or less, more preferably 60% by mass or less.
The solid content in the modified dispersion means the total amount of substances forming the solid content in the molded product formed from the modified dispersion. For example, when the dispersion contains F particles, inorganic particles, and aromatic polyimide, the total content of these components is the solid content in the modified dispersion.

In the modified dispersion, the proportion of the F particles in the solid content is preferably 10% by mass or more, more preferably 20% by mass or more. The proportion of F particles in the solid content is preferably 50% by mass or less, more preferably 40% by mass or less.
In the modified dispersion, the ratio of the inorganic particles to the solid content is preferably 20% by mass or more, more preferably 40% by mass or more. The ratio of the inorganic particles to the solid content is preferably 80% by mass or less, more preferably 70% by mass or less.

The modified dispersion is used for forming insulating layers of printed wiring boards, for bonding ceramic parts and metal parts in automotive engines, and for imparting corrosion resistance to heat exchangers and the fins or tubes that constitute them. Applications: thermal interface material, substrate for power modules, impregnating and drying coils used in power devices such as motors to form a thermally conductive heat-resistant coating layer, coating the inside and outside of glass containers such as medical vials and syringes It can be used for

The modified dispersion has excellent liquid physical properties such as dispersion stability, and can form a molded article having excellent physical properties based on the F polymer and the inorganic particles due to the mechanism of action described above. In addition, it is possible to form a molding exhibiting strong adhesion to the base material.
If the modified dispersion is applied to the surface of the substrate and heated to form a layer containing F polymer and inorganic particles (hereinafter also referred to as “F layer”), the substrate composed of the above substrate can be obtained. A laminate having a material layer and an F layer as a molding (hereinafter also referred to as "this laminate") can be produced.
Preferred embodiments of the laminate include a metal-clad laminate having a metal foil and an F layer formed on at least one surface thereof, and a multilayer film having a resin film and an F layer formed on at least one surface thereof. is mentioned.

The ten-point average roughness of the substrate surface is preferably 0.1 μm or less, more preferably 0.05 μm or less. The ten-point average roughness of the substrate surface is preferably 0.01 μm or more. Since the F layer having excellent adhesion can be formed from the modified dispersion, the laminate tends to have excellent peel strength even when a substrate having excellent smoothness is used.
In the production of the laminate, the F layer may be formed on at least one surface of the base material, the F layer may be formed only on one side of the base material, or the F layer may be formed on both sides of the base material. may
The surface of the substrate may be surface-treated with a silane coupling agent or the like.

When applying the modified dispersion liquid, 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 Meyer bar A coating method such as a method, a slot die coating method, or the like can be used.
The F layer is preferably formed by baking the F polymer by heating after removing the liquid dispersion medium by heating. It is preferable to blow air in the step of removing the liquid dispersion medium.
After removing the liquid dispersion medium, it is preferable to heat the base material to a temperature range where the F polymer is baked, for example, it is preferable to bake the F polymer in the range of 300 to 400°C. The F layer preferably contains a fired product of F particles.

The F layer is formed through the steps of applying the modified dispersion liquid, drying, and firing as described above.
These steps may be performed once or twice or more, and from the viewpoint of obtaining a thick film with excellent smoothness, the steps of coating, drying, and baking the modified dispersion may be performed multiple times.
For example, the modified dispersion is applied to a substrate, and the liquid dispersion medium is removed by heating to form a film. The F layer may be formed by further coating the modified dispersion on the formed film, removing the liquid dispersion medium by heating, and then baking the F polymer by heating.
Alternatively, the modified dispersion is applied to a substrate, the liquid dispersion medium is removed by heating to form a film, and the F polymer is baked by heating to form a baked film. The F layer may be formed by further coating the modified dispersion liquid on the formed baked film, removing the liquid dispersion medium by heating, and baking the F polymer by heating to form a baked film.

In the latter case, the gaseous decomposition product of the non-fluorine-based leveling agent or the atmosphere gas when applying the modified dispersion exists at the boundary between the fired films in the F layer, and microspaces are likely to be formed. it is conceivable that. It is believed that the presence of these microspaces alleviates the difference in stress between the fired films caused by the expansion and contraction of the F polymer, and this laminate is excellent in low linear expansion properties.
The thickness of the F layer is preferably 25 μm or more, more preferably 50 μm or more. The upper limit of thickness is 200 μm. Since the modified dispersion has excellent film-forming properties, such a thick film can be satisfactorily formed, and in this range, an F layer having excellent crack resistance can be easily formed.
The peel strength between the F layer and the substrate layer is preferably 10 N/cm or more, more preferably 15 N/cm or more. The peel strength is preferably 100 N/cm or less. Using the modified dispersion makes it possible to easily form such a laminate without impairing the physical properties of the F polymer in the F layer.

The porosity of the F layer is preferably 5% or less, more preferably 4% or less. The porosity is preferably 0.01% or more, more preferably 0.1% or more.
In addition, the porosity is obtained by determining the void portion of the F layer by image processing from the SEM photograph of the cross section of the molded product observed using a scanning electron microscope (SEM), and the area occupied by the void portion of the F layer. It is the ratio (%) divided by the area. The area occupied by the void portion is obtained by approximating the void portion to a circle.

Substrates include metal substrates such as metal foils made of copper, nickel, aluminum, titanium, and alloys thereof, polyimides, polyarylates, polysulfones, polyallylsulfones, polyamides, polyetheramides, polyphenylene sulfides, and polyallyl ethers. Examples include heat-resistant films made of heat-resistant resins such as ketones, polyamideimides, liquid crystalline polyesters, liquid crystalline polyester amides, and tetrafluoroethylene-based polymers, prepregs that are precursors of fiber-reinforced resin substrates, and glass substrates.
The shape of the base material may be planar, curved, or uneven, and may be any of foil, plate, film, and fibrous.

When the substrate is a metal foil, the substrate may be a low-roughened metal foil or a non-roughened metal foil. The substrate is preferably a non-roughened metal foil, more preferably a non-roughened copper foil. Also in this case, since the F layer has excellent adhesion to the substrate, the laminate tends to have excellent peel strength. Further, in this case, the printed circuit board formed from this laminate tends to have excellent transmission characteristics.

The ten-point average roughness of the substrate surface is preferably 0.1 μm or less, more preferably 0.05 μm or less. The ten-point average roughness is preferably 0.001 μm or more. Even with such a non-roughened base material, the present laminate can form a printed circuit board or the like having excellent peel strength and excellent transmission characteristics. The ten-point average roughness of the surface of the base material is a value specified in Annex JA of JIS B 0601:2013.
The thickness of the substrate is preferably 2-100 μm. When the substrate is a metal foil, the thickness of the substrate is preferably 1-35 μm. The substrate may also be a metal foil with a carrier, which is an ultra-thin copper foil (thickness of 2 to 5 μm) laminated on a copper carrier foil via a release layer.

Specific examples of the present laminate include a metal foil and a metal-clad laminate having an F layer on at least one surface of the metal foil, a polyimide film, and a multilayer film having an F layer on both surfaces of the polyimide film. mentioned. These laminates are excellent in various physical properties such as electrical properties, and are suitable as materials for printed circuit boards and the like. Specifically, such laminates can be used in the production of flexible printed circuit boards and rigid printed circuit boards.

One aspect of the laminate is a laminate of prepreg/F layer/metal foil. The base material is preferably a prepreg having a polymer layer on the surface of the glass cloth obtained by impregnating the glass cloth with the heat-resistant resin that may be contained in the base material. The polymer layer may be formed from a plurality of polymer layers, in which case each polymer layer is preferably formed from a different polymer. Having the F layer between the prepreg and the metal foil is preferable because the prepreg and the metal foil are less likely to separate.
The laminate is useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sporting goods, food industry goods, heat dissipation parts, paints, cosmetics and the like. In the printed circuit board, it can be used as a new printed circuit board material to replace the conventional glass epoxy board in order to prevent the temperature rise of the printed circuit board on which electronic parts are mounted at high density.

Specifically, the laminate can be used as wire coating materials for aircraft wires, enameled wire coating materials used in motors such as electric vehicles, electrical insulating tapes, insulating tapes for oil drilling, materials for printed circuit boards, Separation membranes such as microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes and gas separation membranes, electrode binders for lithium secondary batteries, fuel cells, etc., copy rolls, furniture, automobile dashboards , Covers for home appliances, etc., load bearings, slide shafts, valves, bearings, bushes, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors and food transport belts. Pads, wear strips, tube lamps, test sockets, wafer guides, wear parts for centrifugal pumps, hydrocarbon, chemical and water supply pumps, tools such as shovels, files, awls, saws, boilers, hoppers, pipes, ovens, baking molds , chutes, dies, toilet bowls, container coverings, power devices, transistors, thyristors, rectifiers, transformers, power MOS FETs, CPUs, heat radiating fins, metal heat radiating plates.
More specifically, this laminate is used as a sealing material for processing machines, vacuum ovens, plasma processing equipment, etc. that heat-treat under low oxygen conditions, such as housings of personal computers and displays, electronic device materials, interior and exterior of automobiles, etc. It is useful as a heat dissipation component in processing units such as sputtering and various dry etching devices.

The dispersion of the present invention (hereinafter also referred to as "this dispersion") comprises F particles, inorganic particles, a liquid dispersion medium, a (meth)acrylic leveling agent, a silicone leveling agent, and an alcohol alkoxylate. and at least one non-fluorine-based leveling agent selected from the group, and the proportion of F particles and the proportion of inorganic particles in the total amount is 5 to 40 mass % and 20 to 60 mass % in this order.
The definition and scope of each of the F particles, inorganic particles, liquid dispersion medium and non-fluorinated leveling agent in the present dispersion are the same as those in the present method, including preferred embodiments thereof.
The present dispersion may further contain aromatic polymers, nonionic surfactants, pH adjusters, pH buffers, additives and the like. The definitions and ranges of the aromatic polymer, nonionic surfactant, pH adjuster, pH buffer, and additive in the present dispersion are the same as those in the present method, including preferred embodiments thereof.

The dispersion may be produced by this method or by another method, preferably by this method. In this case, aggregation of the F particles is easily eliminated, and the present dispersion tends to be excellent in dispersion stability.
Other methods include a method of adding F particles, inorganic particles, a liquid dispersion medium and a non-fluorine leveling agent all at once and mixing them, a method of adding a non-fluorine leveling agent to a liquid dispersion medium, and further adding F particles and inorganic particles. A method of sequentially adding and mixing F particles and inorganic particles, a method of pre-mixing each of the F particles and the inorganic particles with a liquid dispersion medium and a non-fluorine leveling agent, and further mixing the resulting two types of mixture. .
As the mixing method and mixing apparatus, the same mixing method and mixing apparatus as in the present method can be used.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these.
1. Preparation of each component and each member [F particle]
F particle 1: containing 97.9 mol%, 0.1 mol%, and 2.0 mol% of TFE units, NAH units, and PPVE units in this order, and a carbonyl group-containing group having 1×10 ⁶ carbon atoms in the main chain Particles (D50: 2.1 μm) made of F polymer 1 having 1000 per particle and a melting temperature of 300 ° C.
F particles 2: Particles made of non-thermally fusible PTFE (D50: 0.3 μm)
[F Dispersion]
F Dispersion 1: Aqueous dispersion containing 60% by mass of F particles 2 (manufactured by AGC, “Product No. AD-915E”)

[Inorganic particles]
Inorganic particles 1: Spherical silica having a D50 of 1 μm surface-treated with phenylaminosilane [Non-fluorine-based leveling agent]
Leveling agent 1: polyether-modified acrylate (manufactured by BYK-Chemie Japan, "BYK-381")
[Aromatic resin varnish]
Varnish 1: Water varnish containing aromatic polyamideimide precursor (PAI1, acid value: 50 mgKOH/g) ("HPC-1000" manufactured by Showa Denko Materials Co., Ltd.)
[Nonionic surfactant]
Surfactant 1: Nonionic surfactant (manufactured by BYK-Chemie Japan, "BYK-3450")

2. Production example of modified dispersion (Example 1)
First, F particles 1, inorganic particles 1, varnish 1, surfactant 1, aqueous ammonia and ammonium bicarbonate were put into a pot, and zirconia balls were put thereinto. After that, the pot was rolled at 150 rpm for 1 hour to prepare original dispersion liquid 1 (content of inorganic particles 1: 45% by mass).
Into another pot, raw dispersion liquid 1 and leveling agent 1 were charged, and zirconia balls were charged. After that, after rolling the pot at 150 rpm for 1 hour, the F dispersion liquid 1 was further added to the pot, and the pot was rolled at 150 rpm for 1 hour to obtain F particles 1 (18.5 parts by mass) and F particles as a whole. 2 (20 parts by mass), inorganic particles 1 (60 parts by mass), PAI1 (1.5 parts by mass), surfactant (1 part by mass), leveling agent 1 (2 parts by mass), aqueous ammonia (100 parts by mass) and modified dispersion liquid 1 (viscosity: 300 mPa·s, pH: 8.0) containing ammonium hydrogen carbonate.
The surface tension of the modified dispersion 1 was lower than that of the original dispersion 1, the difference being 0.1 to 1 mN/m, and the dispersion layer ratio being 60% or more.

3. Laminate Production Example A modified dispersion 1 was applied to the surface of a long non-roughened copper foil (surface ten-point average roughness: 0.1 μm or less, thickness: 18 μm) using a bar coater. , forming a wet film. Next, the copper foil on which the wet film was formed was passed through a drying furnace at 110° C. for 5 minutes and dried by heating to obtain a dry film. After that, the dry film was heated at 380° C. for 3 minutes in an oven in a nitrogen gas atmosphere. Thus, a laminate 1 having a copper foil and a polymer layer (thickness: 50 μm) as a molded product containing F polymer 1, PTFE, inorganic oxide particles 1 and PAI1 on its surface was produced.
When a laminate was produced in the same manner as laminate 1 except that original dispersion 1 was used instead of the modified dispersion, cracks were found in the polymer layer having a thickness of 100 μm.

The copper foil of the laminate 1 was removed by etching with an aqueous ferric chloride solution to prepare a single polymer layer, and the dielectric loss tangent was measured by the SPDR (split post dielectric resonance, measurement frequency: 10 GHz) method. As a result, the dielectric loss tangent of the polymer layer was 0.0010 or less.
The copper foil of the laminate 1 was removed by etching with an aqueous solution of ferric chloride to prepare a single polymer layer, and a square test piece of 180 mm square was cut out. The coefficient of linear expansion of the cut test piece was measured in the range of 25 to 260° C. according to the measuring method specified in JIS C 6471:1995. The coefficient of linear expansion of the test piece was 30 ppm/°C or less.

A rectangular test piece having a length of 100 mm and a width of 10 mm was cut out from the laminate 1 . A position 50 mm from one end in the length direction of the test piece was fixed, and the copper foil and the polymer layer were separated from one end in the length direction at a pulling speed of 50 mm/min at 90° to the test piece. The maximum load at the time of peeling was defined as the peel strength (N/cm). The peel strength of the laminate 1 was 10 N/cm or more.
In addition, the inorganic particles 1 were firmly supported in the polymer layer and did not fall off.

As is clear from the above results, the modified dispersion prepared by this method is excellent in dispersion stability and film-forming properties, and the F layer obtained by applying it to the substrate has excellent electrical properties and low linear expansion. was excellent in character. In addition, the adhesion between the F layer and the substrate layer was excellent, and the inorganic particles were firmly supported in the F layer. Therefore, it is considered that the laminate formed from the modified dispersion obtained by this method has excellent uniformity of component distribution and exhibits the properties of the F polymer and the inorganic particles to a high degree. In addition, it is believed that no voids are generated at the interfaces of the layers, and a decrease in water resistance is suppressed.

Claims (15)

A non-fluorine leveling agent is added to a dispersion containing tetrafluoroethylene-based polymer particles, inorganic particles, and a liquid dispersion medium, wherein the proportion of the inorganic particles in the total amount is 20 to 60% by mass, and the dispersion is obtained. A method for producing a modified dispersion, wherein the surface tension of the modified dispersion is reduced to obtain a modified dispersion. 2. The production method according to claim 1, wherein the tetrafluoroethylene-based polymer particles include heat-melting tetrafluoroethylene-based polymer particles and non-heat-melting tetrafluoroethylene-based polymer particles. The production method according to claim 1 or 2, wherein the tetrafluoroethylene-based polymer has a melting temperature of 200 to 325°C. The production method according to any one of claims 1 to 3, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having a carbonyl group-containing group or a hydroxyl group-containing group. The production method according to any one of claims 1 to 4, wherein the inorganic particles are silica particles. The production according to any one of claims 1 to 5, wherein the non-fluorine leveling agent is at least one selected from the group consisting of (meth)acrylic leveling agents, silicone leveling agents and alcohol alkoxylates. Method. The production method according to any one of claims 1 to 6, wherein the liquid dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters. The production method according to any one of claims 1 to 7, wherein the difference between the surface tension of the modified dispersion and the surface tension of the dispersion is 1 mN/m or less. The production method according to any one of claims 1 to 8, wherein the dispersion further contains an aromatic polymer. The production method according to any one of claims 1 to 9, wherein the dispersion further contains a nonionic surfactant. The modified dispersion obtained by the production method according to any one of claims 1 to 10 is applied to the surface of a substrate and heated to obtain a polymer containing the tetrafluoroethylene-based polymer and the inorganic particles. A method for producing a laminate, comprising forming layers to obtain a laminate having a substrate layer composed of the substrate and the polymer layer. 12. The manufacturing method according to claim 11, wherein the polymer layer has a thickness of 25 [mu]m or more. The manufacturing method according to claim 11 or 12, wherein the ten-point average roughness of the surface of the base material is 0.1 µm or less. Tetrafluoroethylene polymer particles, inorganic particles, a liquid dispersion medium, and at least one non-fluorine leveling agent selected from the group consisting of (meth)acrylic leveling agents, silicone leveling agents and alcohol alkoxylates wherein the proportion of the tetrafluoroethylene-based polymer particles and the proportion of the inorganic particles in the total amount are 5 to 40% by mass and 20 to 60% by mass in this order. 15. The dispersion according to claim 14, wherein the liquid dispersion medium is at least one selected from the group consisting of water, amides, ketones and esters.