WO2012029929A1 - Method for producing fluororesin organosol, fluororesin organosol, and coating composition - Google Patents

Abstract

Provided are: a method for producing a fluororesin organosol at a relatively low temperature wherein a fluorine-containing copolymer (ETFE) containing a repeat unit based on ethylene and a repeat unit based on tetrafluoroethylene is dispersed evenly and at a high concentration in an organic medium; a fluororesin organosol obtained by means of said method; and a coating composition having the fluororesin organosol as the primary component. The method for producing a fluororesin organosol has as a dispersing medium a solvent that can dissolve ETFE at a temperature that is no greater than the melting point of ETFE with ETFE as the dispersoid, and is characterized by having: a dissolution step for dissolving ETFE in the solvent to form a solution; a precipitation step for precipitating ETFE from the solution as microparticles in the solvent; and a cracking/dispersing step for evenly dispersing the ETFE microparticles in the solvent by applying a high shearing force to the mixture of ETFE and the solvent containing ETFE as microparticles.

Description

Method for producing fluororesin organosol, fluororesin organosol and coating composition

The present invention relates to a method for producing a fluororesin organosol, a fluororesin organosol obtained thereby, and a coating composition comprising this as a main component.

Fluororesin is excellent in solvent resistance, low dielectric properties, low surface energy, non-adhesiveness, weather resistance, etc., and is used in various applications that cannot be used with general-purpose plastics. Among them, ethylene / tetrafluoroethylene copolymer (hereinafter also referred to as ETFE) is excellent in heat resistance, flame resistance, chemical resistance, weather resistance, low friction, low dielectric properties, transparency, and the like. It is used in a wide range of fields such as coating materials for electric wires, corrosion-resistant piping materials for chemical plants, vinylhouse materials for agriculture, and mold release films.

However, since ETFE is generally insoluble in a solvent and cannot form a coating film by applying a solution, the ETFE molding method is extrusion molding, injection molding, powder, except for special cases such as the following patent documents. The method is limited to a method in which ETFE is melted by heat, such as painting.

Known methods for forming an ETFE coating film on a substrate include a rotary melt molding method of ETFE powder and an electrostatic powder coating method. However, these methods require special equipment.
Furthermore, in order to form a coating film with sufficient physical properties that adheres closely to the substrate and does not have pinholes, it is necessary to melt and mold ETFE as described above, that is, to heat to a temperature higher than the melting point of ETFE. It was. Therefore, it has been difficult to form an ETFE coating film on a base material that deforms below the melting point of ETFE.

On the other hand, attempts to obtain ETFE solutions have been reported. For example, according to Patent Document 1, Patent Document 2, and Patent Document 3, a high boiling point compound such as diisobutyl adipate and ETFE are stirred at a high temperature of 230 ° C. or more to dissolve ETFE, and then stirred more vigorously. The ETFE suspension is obtained by cooling while cooling. Next, ETFE is separated by filtration, and further dispersed in a mixed solvent of kerosene and diisobutyl adipate to obtain an ETFE dispersion. There is a description that the dispersion was applied to a copper wire and a coating film was formed at a high temperature of 450 ° C. However, this method requires complicated operations for the preparation of the ETFE suspension, and a high-temperature treatment step is required to obtain an ETFE-coated electric wire having sufficient physical properties.

In addition, an attempt to obtain an ETFE solution using oil of a low molecular weight chlorotrifluoroethylene oligomer as a medium has been reported (see Patent Document 4). However, since the oil has a high boiling point and is difficult to dry, it is not easy to use for forming an ETFE coating film. Furthermore, the ETFE dispersion obtained using the oil does not have fluidity near room temperature and cannot be applied to the formation of a coating film.

However, recently, as disclosed in Patent Documents 5 and 6, there has been reported an example in which ETFE is dissolved in a specific medium at a temperature lower by 50 ° C. or more than the melting point of ETFE. When this method is used, a solution of ETFE can be obtained at a relatively low temperature, and by cooling this, an ETFE dispersion can be obtained. However, when the concentration of ETFE is increased, gelation or uniform There were problems such as the inability to obtain a dispersion.

US Pat. No. 2,412,960 US Pat. No. 2,448,952 US Pat. No. 2,484,483 U.S. Pat. No. 4,933,388 International Publication No. 2010/044421 Specification International Publication No. 2010/044445 Specification

The present invention has been made in view of the above circumstances, and a fluorine-containing copolymer containing a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene is dispersed at a high concentration and uniformly in an organic medium. It is an object of the present invention to provide a method for producing a resin organosol at a relatively low temperature, a fluororesin organosol obtained by the method, and a coating composition comprising this as a main component.

The present invention provides a fluororesin organosol production method having the following constitution, a fluororesin organosol obtained by the method, and a coating composition using the fluororesin organosol.
[1] A fluorine-containing copolymer having a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene is used as a dispersoid, and the fluorine-containing copolymer is dissolved at a temperature lower than the melting point of the fluorine-containing copolymer. A method for producing a fluororesin organosol using a solvable solvent as a dispersion medium,
A dissolution step of dissolving the fluorine-containing copolymer in the solvent to form a solution;
A precipitation step of precipitating the fluorine-containing copolymer as fine particles in the solvent in the solution;
A crushing / dispersing step of uniformly dispersing fine particles of the fluorinated copolymer in the solvent by applying a high shear force to the mixture of the solvent and the fluorinated copolymer containing the fluorinated copolymer as fine particles. When,
A process for producing a fluororesin organosol, comprising:

[2] The method for producing a fluororesin organosol according to [1], wherein the precipitation step and the crushing / dispersing step are performed simultaneously.
[3] The high shear force is applied by at least one method selected from the group consisting of high-speed rotation, high-pressure injection, high-speed vibration, ultrasonic treatment, and high-pressure filtration. Of manufacturing fluororesin organosols.
[4] The method for producing a fluororesin organosol according to any one of [1] to [3], wherein the dissolution is performed at a temperature not lower than 40 ° C. and not higher than the melting point of the fluorine-containing copolymer, and the precipitation is performed by cooling. .

[5] The blending ratio of the fluorinated copolymer and the solvent in the dissolving step is 1.0: 99.0 to 70.0: 30.0 in a mass ratio represented by the fluorinated copolymer: solvent. [1] The method for producing a fluororesin organosol according to any one of [4].
[6] The solvent index according to any one of [1] to [5], wherein a solubility index (R) for the fluorinated copolymer based on a Hansen solubility parameter represented by the following formula (1) in the solvent is less than 25: A method for producing a fluororesin organosol.
R = 4 × (δd−15.7) ² + (δp−5.7) ² + (δh−4.3) ² (1)
(In the formula (1), δd, δp, and δh respectively represent a dispersion term, a polar term, and a hydrogen bond term in the Hansen solubility parameter.)
[7] The average particle diameter of the fluorine-containing copolymer fine particles is in the range of 0.005 to 5 μm as the number average particle diameter measured by a dynamic light scattering method at 25 ° C. [1] to [6 ] The manufacturing method of the fluororesin organosol in any one of.

[8] The method for producing a fluororesin organosol according to any one of [1] to [7], wherein the high shear force is applied in the presence of a viscosity modifier.
[9] In the viscosity modifier, an alkyl group having 1 to 20 carbon atoms, which may be substituted with a halogen group or any —CH ₂ — other than a bond terminal may be substituted with an oxygen atom, and an amino group And a method for producing a fluororesin organosol according to any one of [1] to [8], which is a compound having at least one functional group selected from the group consisting of amide group, sulfonamide group, hydroxyl group and mercapto group .
[10] Any of [1] to [9], wherein the proportion of repeating units based on comonomer other than tetrafluoroethylene and ethylene constituting the fluorine-containing copolymer is 0.1 to 50 mol% A process for producing a fluororesin organosol as described above.
[11] The fluorinated copolymer is a fluorinated copolymer having at least one selected from the group consisting of a carboxylic acid group, an acid anhydride group and a carboxylic acid halide group. [1] to [10] The manufacturing method of the fluororesin organosol in any one of.
[12] A fluororesin organosol obtained by the production method according to any one of [1] to [11].
[13] A coating composition comprising as a main component a fluororesin organosol obtained by the production method according to any one of [1] to [11].

According to the present invention, a fluororesin organosol in which a fluorine-containing copolymer containing a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene is uniformly dispersed in an organic medium at a high concentration can be produced at a relatively low temperature. . In addition, when the fluororesin organosol of the present invention and the coating composition containing this as a main component are used, a uniform coating film can be formed by a simple method of applying and drying at a relatively low temperature.

2 is a transmission electron microscope (TEM) photograph (100,000 times) of ETFE fine particles contained in the fluororesin organosol prepared in Example 1. FIG. It is an optical microscope photograph (100 times) of the ETFE coating film surface obtained using the fluororesin organosol produced in Example 1.

Hereinafter, embodiments of the present invention will be described in detail.
In this specification, the organosol refers to a substance in which solid fine particles are dispersed in an organic solvent. The fluororesin organosol refers to one containing fluororesin fine particles as the solid fine particles.
[Method for producing fluororesin organosol]
The present invention uses a fluorine-containing copolymer having a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene as a dispersoid, and dissolves the fluorine-containing copolymer at a temperature below the melting point of the fluorine-containing copolymer. A method for producing a fluororesin organosol using a solvable solvent as a dispersion medium, comprising the following (1) dissolution step, (2) precipitation step, and (3) pulverization / dispersion step.
(1) Dissolution step of dissolving the fluorine-containing copolymer in the solvent to form a solution (2) Precipitation step of depositing the fluorine-containing copolymer as fine particles in the solvent in the solution (3) The fluorine-containing A crushing / dispersing step of uniformly dispersing fine particles of the fluorinated copolymer in the solvent by applying a high shearing force to a mixture of the solvent and the fluorinated copolymer containing the copolymer as fine particles.

The fluororesin organosol obtained by the production method of the present invention is any other temperature and pressure as long as it exhibits the properties of the organosol under normal temperature (5 ° C. to 40 ° C.) and normal pressure (0.1 MPa) conditions. The property under the conditions is not particularly limited. For example, it may be in a solution state at a temperature not lower than normal temperature and not higher than the melting point of the fluorine-containing copolymer. Further, the fluororesin organosol obtained by the production method of the present invention may contain other optional components as long as the fluoropolymer fine particles and the solvent, which are essential components, form an organosol. Good.

(1) Dissolution Step The dissolution step in the production method of the present invention comprises a fluorine-containing copolymer containing a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene, which becomes a dispersoid in the form of fine particles in the fluororesin organosol. Is dissolved in a solvent that functions as a dispersion medium in the fluororesin organosol and that can dissolve the fluorocopolymer at a temperature not higher than the melting point of the fluorocopolymer.

(Fluorine-containing copolymer)
The fluorine-containing copolymer used in the method for producing the fluororesin organosol of the present invention is particularly limited as long as it is a fluorine-containing copolymer containing a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene. Not. As an example of such a fluorine-containing copolymer, specifically, a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene (CF ₂ = CF ₂ : TFE) are the main repeating units in the copolymer. ETFE and the like. Here, in this specification, the term “ETFE” may include a repeating unit based on a comonomer other than TFE and ethylene as a constituent unit of the copolymer, and the main component in the copolymer of TFE and ethylene. It is used as a general term for fluorine-containing copolymers having repeating units.

As ETFE in the present invention, the molar ratio of the repeating unit based on TFE / the repeating unit based on ethylene is preferably 70/30 to 30/70, more preferably 65/35 to 40/60, and most preferably 65/35. To 45/55.

In addition, ETFE in the present invention may contain a repeating unit based on a comonomer (comonomer) other than TFE and ethylene in order to add various functions to the obtained copolymer. preferable. Examples of such comonomer include fluoroethylenes such as CF ₂ = CFCl and CF ₂ = CH ₂ (excluding TFE); CF ₂ = CFCF ₃ , CF ₂ = CHCF ₃ , CH ₂ = CHCF hexafluoropropylene such as _{3; CF 3 CF 2 CH =} CH 2, CF 3 CF 2 CF 2 CF 2 CH = CH 2, CF 3 CF 2 CF 2 CF 2 CF = CH 2, CF 2 HCF 2 CF 2 CF = the number of carbon atoms of the CH ₂ or the like having a fluoroalkyl group having 2 to 12 (polyfluoroalkyl) ^{_{ethylenes; R f (OCFXCF 2) m}} OCF = CF 2 ( wherein ^{R f} is perfluoroalkyl of 1 to 6 carbon atoms group, X is a fluorine atom or a trifluoromethyl group, m represents an integer of 0-5) perfluorovinyl ethers such _{as;. CH 3 OC (= O} ) _{F 2 CF 2 CF 2 OCF =} CF 2 or _{FSO 2 CF 2 CF 2 OCF (} CF 3) CF 2 such OCF = CF _2, easily perfluorovinyl ethers having a group convertible to a carboxylic acid group or a sulfonic acid group ; C3 olefins having 3 carbon atoms such as propylene, C4 olefins having 4 carbon atoms such as butylene and isobutylene, olefins such as 4-methyl-1-pentene, cyclohexene, styrene and α-methylstyrene (excluding ethylene) ); Vinyl esters such as vinyl acetate, vinyl lactate, vinyl butyrate, vinyl pivalate, vinyl benzoate; allyl esters such as allyl acetate; methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether , Cyclohexylvini Ethers such as ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, polyoxyethylene vinyl ether, 2-aminoethyl vinyl ether, glycidyl vinyl ether, 2- (vinyloxy) tetrahydro-2H-pyran; methyl (meth) acrylate, Ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-Aminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2-isocyanatoethyl (meth) acrylate, 3- (trimethoxysilyl) propyl (meth) acrylate, 3- (meth) acrylic acid 3- ( Torie Toki (Meth) acrylic esters such as (silyl) propyl; (meth) acrylamides such as (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropylacrylamide, N, N-dimethyl (meth) acrylamide; acrylonitrile, etc. Cyano group-containing monomers; dienes such as isoprene and 1,3-butadiene; chloroolefins such as vinyl chloride and vinylidene chloride; maleic anhydride, itaconic anhydride, citraconic anhydride, 5-norbornene-2, And vinyl compounds containing a carboxylic acid anhydride such as 3-dicarboxylic acid anhydride.
These comonomers may be used alone or in combination of two or more.

When the ETFE contains a repeating unit based on a comonomer other than TFE and ethylene, the content is preferably 0.1 to 50 mol% in all monomer repeating units of ETFE. More preferably, it is 1 to 30 mol%, most preferably 0.1 to 20 mol%, and still more preferably 0.1 to 10 mol%. In the ETFE used in the production method of the present invention, if the content of the repeating unit based on a comonomer other than TFE and ethylene is within this range, the characteristics of ETFE composed only of TFE and ethylene are not impaired. , Functions such as high solubility, water repellency, oil repellency, crosslinkability, and adhesion to a substrate can be imparted.

In addition, from the viewpoint of adhesion to the substrate, ETFE used in the production method of the present invention may have a functional group having adhesion to the substrate in the molecular structure. The functional group may be present either at the molecular end of ETFE or at the side chain or main chain. Further, one kind of the functional group may be used alone in ETFE, or two or more kinds may be used in combination. The kind and content of the functional group having adhesiveness to the substrate are appropriately selected according to the required performance depending on the use in which the fluororesin organosol obtained by this production method is used. For example, when used as a coating composition, it is appropriately selected depending on the type, shape, application, required adhesiveness, adhesion method, functional group introduction method, and the like of the substrate on which the composition is applied.

Specific examples of the functional group having adhesiveness to the substrate include a carboxylic acid group, a residue obtained by dehydration condensation of two carboxyl groups in one molecule (hereinafter referred to as an acid anhydride group), a hydroxyl group, Consists of sulfonic acid group, epoxy group, cyano group, carbonate group, isocyanate group, ester group, amide group, aldehyde group, amino group, hydrolyzable silyl group, carbon-carbon double bond, ether group and carboxylic acid halide group There may be mentioned at least one selected from the group. The carboxylic acid group is a carboxyl group and a salt thereof (—COOM ¹ : M ¹ is a metal atom or atomic group capable of forming a salt with a carboxylic acid), and the sulfonic acid group is a sulfo group and a salt thereof (—SOSO ₃ M ² : M ² means a metal atom or atomic group capable of forming a salt with sulfonic acid.
Among the above functional groups, particularly selected from the group consisting of carboxylic acid groups, acid anhydride groups, hydroxyl groups, epoxy groups, carbonate groups, hydrolyzable silyl groups, carbon-carbon double bonds, and carboxylic acid halide groups. At least one is preferred. Most preferably, it is at least one selected from the group consisting of a carboxylic acid group, an acid anhydride group, and a carboxylic acid halide group. Two or more different functional groups may exist in one molecule of the fluorine-containing copolymer, or two or more functional groups may exist in one molecule.

As a method of introducing an adhesive functional group (hereinafter also referred to as “adhesive functional group”) into ETFE, (i) a copolymerizable monomer having an adhesive functional group at the time of polymerization of ETFE (Ii) a method of introducing an adhesive functional group into the molecular terminal of ETFE at the time of polymerization by a polymerization initiator having an adhesive functional group, a chain transfer agent, or the like (iii) ) A method of grafting a compound (graft compound) having an adhesive functional group and a functional group capable of grafting onto ETFE. These introduction methods can be used alone or in appropriate combination. In consideration of durability, ETFE produced by the above method (i) and / or (ii) is preferable.
In addition to the adhesive functional group, functional groups having various functions introduced as necessary can be introduced into ETFE in the same manner as the adhesive functional group is introduced.

In the production method of the present invention, a commercially available product can also be used as the fluorine-containing copolymer having the repeating unit based on ethylene and the repeating unit based on TFE. As a commercial product of such a fluorine-containing copolymer: ETFE, specifically, Asahi Glass Co., Ltd .: Fluon (registered trademark) ETFE Series, Fluon (registered trademark) LM-ETFE Series, Fluon (registered trademark) LM-ETFE AH Series, Daikin Industries, Ltd .: Neofron (registered trademark), Dyneon: Dyneon (registered trademark) ETFE, DuPont: Tefzel (registered trademark), and the like.
The melting point of the fluorinated copolymer in the present invention is preferably 130 to 275 ° C, more preferably 140 to 265 ° C, and most preferably 150 to 260 ° C. When it is in this range, the solubility in a solvent in the dissolution step is excellent, and the strength is also excellent.

The volume flow rate (hereinafter referred to as Q value) of the fluorinated copolymer used in the present invention is preferably 0.1 to 2000 mm ³ / sec. The Q value is an index representing the melt fluidity of the fluorinated copolymer and is a measure of the molecular weight. A large Q value indicates a low molecular weight, and a small Q value indicates a high molecular weight. The Q value in the present specification is a fluorine content when extruded into an orifice having a diameter of 2.1 mm and a length of 8 mm under a load of 7 kg at a temperature 50 ° C. higher than the melting point of the resin using a flow tester manufactured by Shimadzu Corporation. It is the extrusion rate of the copolymer. When the Q value is too small, the solubility is deteriorated. When the Q value is too large, the mechanical strength of the fluorinated copolymer is lowered, and cracks and the like are easily generated when the coating film is formed. Q value of the fluorocopolymer used in the present invention is more preferably 5 ~ 500 mm ³ / sec, and most preferably 10 ~ 200 mm ³ / sec. Within this range, the fluorine-containing copolymer is excellent in mechanical strength, and when used as a coating composition, the coating film does not crack and the coating film characteristics are excellent.
In the production method of the present invention, one type of these fluorine-containing copolymers can be used alone, or two or more types can be used in combination.

(solvent)
The solvent used in the method for producing the fluororesin organosol of the present invention is a solvent that can dissolve the fluorocopolymer at a temperature not higher than the melting point of the fluorocopolymer. After the copolymer fine particles are precipitated and uniformly dispersed, the solvent functions as a dispersion medium for allowing the fine particles to exist in a dispersed state at least at normal temperature and pressure.

As the solvent in the present invention, various solvents can be mentioned as long as they meet the above conditions. Here, in order for the solvent to be used to meet the above conditions, the polarity of the solvent is preferably within a specific range. In the present invention, the following method is used, in which a solvent that satisfies the above conditions is selected as a solvent having a certain range of polarity based on Hansen solubility parameters (Hansen solubility parameters).

The Hansen solubility parameter is obtained by dividing the solubility parameter introduced by Hildebrand into three components: a dispersion term δd, a polar term δp, and a hydrogen bond term δh, and representing it in a three-dimensional space. The dispersion term δd indicates the effect due to the dispersion force, the polar term δp indicates the effect due to the force between the dipoles, and the hydrogen bond term δh indicates the effect due to the hydrogen bond force.

The definition and calculation of Hansen solubility parameters are described in Charles M. et al. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007). In addition, by using computer software Hansen Solubility Parameters in Practice (HSPiP), the Hansen solubility parameter can be easily estimated from the chemical structure of a medium whose literature values are not known.
For the solvent in the present invention, use HSPiP version 3 to select the solvent to be used by using the value for the solvent registered in the database and the estimated value for the solvent not registered. did.

In general, the Hansen solubility parameter for a particular polymer can be determined by a solubility test in which a sample of the polymer is dissolved in a number of different solvents for which the Hansen solubility parameter is established and the solubility is measured. Specifically, among the solvents used in the solubility test, all the three-dimensional points of the solvent in which the polymer is dissolved are encapsulated inside the sphere, and the non-dissolved solvent points are outside the sphere ( Solubility sphere) is found and the center coordinates of the sphere are taken as the Hansen solubility parameter of the polymer.

Here, for example, when the Hansen solubility parameter of another solvent that has not been used for the measurement of the Hansen solubility parameter of the polymer is (δd, δp, δh), the point indicated by the coordinates is the solubility of the polymer. If encapsulated inside the sphere, the solvent is believed to dissolve the polymer. On the other hand, if the coordinate point is outside the solubility sphere of the polymer, it is considered that this solvent cannot dissolve the polymer.

In the present invention, the Hansen solubility parameter is used to dissolve the fluorine-containing copolymer contained in the fluororesin organosol at a temperature below its melting point, and the fluorine-containing copolymer is used as fine particles at room temperature. With reference to diisopropyl ketone, which is the optimum solvent to be dispersed, a solvent group at a certain distance from the coordinates (15.7, 5.7, 4.3), which is the Hansen solubility parameter, can be used as a preferred solvent.

That is, R, which is a value based on the Hansen solubility parameter represented by the following formula (1), was used as a solubility index for the fluorine-containing copolymer: ETFE.
R = 4 × (δd−15.7) ² + (δp−5.7) ² + (δh−4.3) ² (1)
(In the formula (1), δd, δp, and δh represent a dispersion term, a polar term, and a hydrogen bond term in the Hansen solubility parameter, respectively, and the unit is (MPa) ^1/2 .)

The solvent in the present invention preferably has a solubility index (R) calculated by the above formula (1) using Hansen solubility parameter coordinates (δd, δp, δh) of the solvent of less than 25, preferably less than 16. More preferably, it is most preferably less than 9. A solvent having a Hansen solubility parameter in which R represented by the above formula (1) falls within this range has high affinity with the fluorine-containing copolymer, and high solubility and fine particle dispersibility.

In addition, the solvent in the present invention may be a solvent composed of one compound or a mixed solvent of two or more compounds, and includes the value of R calculated based on the Hansen solubility parameter according to the above formula (1). It can be used as a solubility index of a fluorine copolymer. For example, when a mixed solvent is used, an average Hansen solubility parameter based on the mixing ratio (volume ratio) of the solvent to be used is obtained, and the solubility index (R) can be calculated using the Hansen solubility parameter.

In addition, the boiling point of the solvent in the present invention is preferably 210 ° C. or less, more preferably 200 ° C. or less, and most preferably 180 ° C. or less from the viewpoints of handleability and solvent removal after coating. Further, if the boiling point of the solvent is too low, for example, there is a problem that bubbles are likely to be generated at the time of evaporation removal (hereinafter also referred to as drying) of the solvent after coating the composition. More preferably, it is 80 ° C. or higher.

As the solvent satisfying the above conditions, ketones having 3 to 10 carbon atoms, esters, carbonates, ethers and the like are preferable, and ketones and esters having 5 to 9 carbon atoms are more preferable. . Specific examples include methyl ethyl ketone, 2-pentanone, methyl isopropyl ketone, 2-hexanone, methyl isobutyl ketone, pinacholine, 2-heptanone, 4-heptanone, diisopyrrole ketone, isoamyl methyl ketone, 2-octanone, 2-nonanone. , Diisobutyl ketone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-ethylcyclohexanone, 2,6-dimethylcyclohexanone, 3,3,5-trimethylcyclohexanone, isophorone, (-)-fencon, ethyl formate, propyl formate, formic acid Isopropyl, butyl formate, isobutyl formate, sec-butyl formate, t-butyl formate, amyl formate, isoamyl formate, hexyl formate, cyclohexyl formate, heptyl formate, octyl formate, 2-ethylhexyl formate , Methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, t-butyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, cyclohexyl acetate, heptyl acetate, octyl acetate, 2-acetate Ethylhexyl, 2,2,2-trifluoroethyl acetate, 2,2,3,3-tetrafluoropropyl acetate, 1,1,1,3,3,3-hexafluoro-2-propyl acetate, 2,2 acetate -Bis (trifluoromethyl) propyl, acetic acid 2,2,3,4,4,4-hexafluorobutyl, acetic acid 2,2,3,3,4,4,5,5-octafluoropentyl, acetic acid 3, 3,4,4,5,5,6,6,6-nonafluorohexyl, acetic acid 4,4,5,5,6,6,7,7,7-nonafluoroheptyl, acetic acid 7, , 8,8,8-pentafluorooctyl, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, sec-butyl propionate, t-butyl propionate, amyl propionate , Isoamyl propionate, hexyl propionate, cyclohexyl propionate, heptyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, sec-butyl butyrate, t-butyl butyrate, amyl butyrate, isoamyl butyrate Hexyl butyrate, cyclohexyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, butyl isobutyrate, isobutyl isobutyrate, sec-butyl isobutyrate, t-butyl isobutyrate Chill, amyl isobutyrate, isoamyl isobutyrate, hexyl isobutyrate, cyclohexyl isobutyrate, methyl valerate, ethyl valerate, propyl valerate, isopropyl valerate, butyl valerate, isobutyl valerate, sec-butyl valerate, valeric acid t-butyl, amyl valerate, isoamyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, butyl isovalerate, isobutyl isovalerate, sec-butyl isovalerate, iso T-butyl valerate, isoamyl valerate, isoamyl isovalerate, methyl hexanoate, ethyl hexanoate, propyl hexanoate, isopropyl hexanoate, butyl hexanoate, isobutyl hexanoate, sec-butyl hexanoate, t-hexanoic acid t- Butyl, methyl heptanoate, ethyl heptanoate, Propyl tanoate, isopropyl heptanoate, methyl octoate, ethyl octoate, methyl nonanoate, methyl cyclohexanecarboxylate, ethyl cyclohexanecarboxylate, propyl cyclohexane carboxylate, isopropyl cyclohexane carboxylate, cyclohexanecarboxylic acid 2,2,2-tri Fluoroethyl, bis (2,2,2-trifluoroethyl) succinate, bis (2,2,2-trifluoroethyl) glutarate, ethyl trifluoroacetate, propyl trifluoroacetate, isopropyl trifluoroacetate, trifluoro Butyl acetate, isobutyl trifluoroacetate, sec-butyl trifluoroacetate, t-butyl trifluoroacetate, amyl trifluoroacetate, isoamyl trifluoroacetate, hexyl trifluoroacetate, trifluoro Heptyl acid, octyl trifluoroacetate, 2-ethylhexyl trifluoroacetate, methyl difluoroacetate, ethyl difluoroacetate, 2-propoxyethyl acetate, 2-butoxyethyl acetate, 2-pentyloxyethyl acetate, 2-hexyloxyethyl acetate, 1 -Ethoxy-2-acetoxypropane, 1-propoxy-2-acetoxypropane, 1-butoxy-2-acetoxypropane, 1-pentyloxy-2-acetoxypropane, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, acetic acid 3 -Propoxybutyl, 3-butoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, 3-ethoxy-3-methylbutyl acetate, 3-propoxy-3-methylbutyl acetate, 4-methoxybutyl acetate, 4-ethoxybutyl acetate, acetic acid 4-propoxybuty , 4-butoxybutyl acetate, methyl pentafluorobenzoate, ethyl pentafluorobenzoate, methyl 3- (trifluoromethyl) benzoate, methyl 3,5-bis (trifluoromethyl) benzoate, 2,2 benzoic acid , 2-trifluoroethyl, benzoic acid 2,2,3,3-tetrafluoropropyl, benzoic acid 2,2,3,3,3-pentafluoropropyl, benzoic acid 1,1,1,3,3,3 Hexafluoro-2-propyl, 2,2-bis (trifluoromethyl) propyl benzoate, 2,2,3,3,4,4,4-heptafluorobutyl benzoate, 2,2,3, benzoic acid 4,4,4-hexafluorobutyl, benzoic acid 2,2,3,3,4,4,5,5,5-nonafluoropentyl, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, dicarbonate Chill, bis (2,2,2-trifluoroethyl) carbonate, bis (2,2,3,3-tetrafluoropropyl) carbonate, tetrahydrofuran, pentafluoroanisole, 3,5-bis (trifluoromethyl) anisole, etc. Is mentioned. In addition, all of these solvents are solvents in which R calculated from the above formula (1) is less than 25.

Among these, the following compounds can be specifically exemplified as more preferable compounds as the solvent used in the present invention.
Methyl ethyl ketone, 2-pentanone, methyl isopropyl ketone, 2-hexanone, methyl isobutyl ketone, pinacholine, 2-heptanone, 4-heptanone, diisopyrrole ketone, isoamyl methyl ketone, 2-octanone, 2-nonanone, diisobutyl ketone, 4 -Ethylcyclohexanone, 3,3,5-trimethylcyclohexanone, isophorone, isopropyl formate, isobutyl formate, sec-butyl formate, t-butyl formate, amyl formate, isoamyl formate, hexyl formate, heptyl formate, octyl formate, 2-ethylhexyl formate , Methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, cyclohexyl acetate, heptyl acetate, octyl acetate, 2-ethylhexyl acetate, Acid 2,2,2-trifluoroethyl, acetic acid 2,2,3,3-tetrafluoropropyl, acetic acid 1,1,1,3,3,3-hexafluoro-2-propyl, acetic acid 2,2-bis (Trifluoromethyl) propyl, 2,2,3,4,4,4-hexafluorobutyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, propionic acid sec-butyl, t-butyl propionate, amyl propionate, isoamyl propionate, hexyl propionate, cyclohexyl propionate, heptyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, sec sec -Butyl, t-butyl butyrate, amyl butyrate Isoamyl butyrate, hexyl butyrate, cyclohexyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, butyl isobutyrate, isobutyl isobutyrate, sec-butyl isobutyrate, t-butyl isobutyrate, amyl isobutyrate, iso Isoamyl butyrate, hexyl isobutyrate, cyclohexyl isobutyrate, methyl valerate, ethyl valerate, propyl valerate, isopropyl valerate, butyl valerate, isobutyl valerate, sec-butyl valerate, t-butyl valerate, amyl valerate , Isoamyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, butyl isovalerate, isobutyl isovalerate, sec-butyl isovalerate, t-butyl isovalerate, iso Amyl valerate, isoamyl isovalerate, hexanoic acid Methyl, ethyl hexanoate, propyl hexanoate, isopropyl hexanoate, butyl hexanoate, isobutyl hexanoate, sec-butyl hexanoate, t-butyl hexanoate, methyl heptanoate, ethyl heptanoate, propyl heptanoate, isopropyl heptanoate, Methyl octoate, ethyl octoate, methyl nonanoate, methyl cyclohexane carboxylate, ethyl cyclohexane carboxylate, propyl cyclohexane carboxylate, isopropyl cyclohexane carboxylate, cyclohexanecarboxylate 2,2,2-trifluoroethyl, bis succinate (2 , 2,2-trifluoroethyl), bis (2,2,2-trifluoroethyl) glutarate, ethyl trifluoroacetate, propyl trifluoroacetate, isopropyl trifluoroacetate, trifluoro Butyl acetoacetate, isobutyl trifluoroacetate, sec-butyl trifluoroacetate, t-butyl trifluoroacetate, amyl trifluoroacetate, isoamyl trifluoroacetate, hexyl trifluoroacetate, heptyl trifluoroacetate, octyl trifluoroacetate, trifluoro 2-ethylhexyl acetate, methyl difluoroacetate, ethyl difluoroacetate, 2-propoxyethyl acetate, 2-butoxyethyl acetate, 2-pentyloxyethyl acetate, 2-hexyloxyethyl acetate, 1-ethoxy-2-acetoxypropane, 1- Propoxy-2-acetoxypropane, 1-butoxy-2-acetoxypropane, 3-ethoxybutyl acetate, 3-propoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, 3-ethoxy-3-methylbutyl acetate, vinegar 4-methoxybutyl, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2,2,3,3-tetrafluoropropyl benzoate, 2,2,3,3,3-pentafluoropropyl benzoate, benzoic acid 1 , 1,1,3,3,3-hexafluoro-2-propyl, 2,2-bis (trifluoromethyl) propyl benzoate, 2,2,3,3,4,4,4-heptafluorobenzoate Butyl, benzoic acid 2,2,3,4,4,4-hexafluorobutyl, benzoic acid 2,2,3,3,4,4,5,5,5-nonafluoropentyl, ethyl methyl carbonate, diethyl carbonate , Dipropyl carbonate, dibutyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, pentafluoroanisole, 3,5-bis (trifluoromethyl) anisole. In addition, all of these solvents are solvents in which R calculated from the above formula (1) is less than 16.

The above solvents may be used alone or in admixture of two or more as long as they satisfy the above conditions of the present invention. Moreover, as long as the said conditions are satisfy | filled, you may mix and use solvents other than the above in the said solvent.

The solvent that can be used in the production method of the present invention in combination with the solvent that can be used alone is not particularly limited as long as the solvent satisfies the above conditions in a mixed solvent state. Specific examples of such combinations include the above pinacholine (Hansen solubility parameters: 15.2, 5.7, 5.3, R: 2.0) and benzonitrile (Hansen solubility parameters: 18.8, 12). 0.0, 3.3, R: 79.1) in a 90:10 volume ratio (Hansen solubility parameter: 15.6, 6.3, 5.1, R: 1.1), t-butyl formate (Hansen solubility parameter: 14.8, 5.4, 7.4, R: 12.9) and acetophenone (Hansen solubility parameter: 18.8, 9.0, 4.0, R: 49.4) Mixed solvent having a volume ratio of 71:29 (hansen solubility parameters: 16.0, 6.4, 6.4, R: 5.3), isobutyl acetate (hansen solubility parameters: 15.1, 3.7, 6.3) , R: 9.4) and methyl benzoate (dissolved in Hansen) (18.9, 8.2, 4.7, R: 47.4) in a volume ratio of 74:26 (Hansen solubility parameter: 16.1, 4.9, 5.9, R: 3. 8), t-butyl formate (Hansen solubility parameter: 14.8, 5.4, 7.4, R: 12.9) and 1,3-bis (trifluoromethyl) benzene (Hansen solubility parameter: 17. 0, 6.8, 0.0, R: 26.5) in a volume ratio of 59:41 (Hansen solubility parameters: 15.7, 6.0, 4.4, R: 0.1), etc. Combinations are mentioned.

In such a mixed solvent, the solubility index (R) calculated from the Hansen solubility parameter and volume ratio of each solvent constituting the mixed solvent is preferably less than 25, more preferably less than 16, and most preferably less than 9. In addition, the said combination is an illustration, Comprising: The mixed solvent which can be used for the manufacturing method of the fluororesin organosol of this invention is not limited to these combinations.

In the method for producing a fluororesin organosol of the present invention, the fluorine-containing copolymer is dissolved in the solvent in the dissolving step to obtain a fluorine-containing copolymer solution. The blending ratio of the fluorine-containing copolymer and the solvent used for the preparation of the fluorine-containing copolymer solution is 1.0: 99.0 to 70.0: 30.30 in a mass ratio represented by the fluorine-containing copolymer: solvent. 0 is preferable, and 2.0: 98.0 to 60.0: 40.0 is more preferable.

In addition, the blending ratio of the fluorinated copolymer and the solvent in the dissolution step is in agreement with the content ratio of the fluorinated copolymer fine particles and the dispersion medium in the obtained fluororesin organosol. When the fluororesin organosol is used as, for example, a coating composition, the blending ratio can be appropriately changed according to the film thickness of the target molded product. When the blending ratio of the fluorine-containing copolymer and the solvent in the fluororesin organosol is within this range, for example, when used as a coating composition, it has excellent handling properties such as viscosity, drying speed, and film uniformity, and contains A homogeneous coating film made of a fluorine copolymer can be formed.

The conditions such as temperature, pressure, and stirring in the dissolution step are not particularly limited as long as the fluorine-containing copolymer is dissolved in the solvent. The temperature condition in the dissolving step is preferably a temperature not higher than the melting point of the fluorine-containing copolymer to be used. Since the melting point of the fluorine-containing copolymer in the present invention, that is, ETFE explained above is the highest at about 275 ° C., the temperature of the step of dissolving it in the solvent is about 275 ° C. or less. Preferably there is. The temperature at which the fluorine-containing copolymer is dissolved in the solvent is more preferably 230 ° C. or less, and particularly preferably 200 ° C. or less. Moreover, as a minimum of the temperature of this melt | dissolution process, 40 degreeC is preferable, 60 degreeC is more preferable, and 80 degreeC is further more preferable when operativity etc. are considered. When the temperature of the melting step is less than 40 ° C., a sufficient dissolved state may not be obtained, and when the temperature exceeds 275 ° C., it may not be easily performed when performing actual work.

In the above-described dissolution step of the method for producing a fluororesin organosol of the present invention, conditions other than temperature are not particularly limited. Usually, it is preferable to dissolve under conditions of normal pressure to slight pressure of about 0.5 MPa. The pressure at the time of dissolution depends on the type of the fluorine-containing copolymer and the solvent, and when the boiling point of the solvent is lower than the temperature of the dissolution process, etc., in the pressure vessel, it is at least lower than the spontaneously generated pressure, preferably 3 MPa or lower, More preferably, it is 2 MPa or less, More preferably, it is 1 MPa or less, Most preferably, it is below normal pressure. In general, it can be dissolved under a pressure of about 0.01 to 1 MPa.

The dissolution time depends on the content of the fluorinated copolymer in the fluororesin organosol obtained by the production method of the present invention, the shape of the fluorinated copolymer, and the like. The shape of the fluorine-containing copolymer to be used is preferably a powder from the viewpoint of work efficiency for shortening the dissolution time. Moreover, the thing of other shapes, such as a pellet form, can also be used from availability.

The dissolution means in the dissolution step is not particularly limited, and a general method can be used. Arbitrary components that are appropriately selected and blended according to the required performance depending on the intended use of the fluorocopolymer and the solvent, which are essential components of the fluororesin organosol, and the intended use of the fluororesin organosol obtained thereby. It is sufficient to weigh the added amount of and uniformly mix and dissolve. When used as a coating composition, it is preferable to add various components described below as optional components.

In addition, in the process of producing the fluororesin organosol of the present invention, as an optional component to be added, for example, a thickener having a function of adjusting viscosity, a thickener, etc., an ultraviolet absorber having a function of preventing deterioration, a light stabilization Agents and the like. In addition, it is preferable that the total compounding quantity of these arbitrary components which the fluororesin organosol obtained in the manufacturing method of this invention contains is 30 mass% or less with respect to the fluororesin organosol whole quantity, and it is 10 mass% or less. More preferred. In other words, the total amount of the fluorine-containing copolymer and the solvent contained in the fluororesin organosol is preferably 70% by mass or more and more preferably 90% by mass or more based on the total amount of the fluororesin organosol.
Furthermore, optional components that function in using the fluororesin organosol can be added to the obtained fluororesin organosol after the following (3) crushing / dispersing step.

The mixing temperature of the fluorinated copolymer, the solvent and the optional component is preferably 40 ° C. or higher and the melting point of the fluorinated copolymer to be used. Specifically, 60 to 230 ° C. is more preferable, and 80 to 200 ° C. is most preferable. In the melting step, mixing and heating of various raw material components may be performed simultaneously, or after mixing various raw material components, heating may be performed while stirring as necessary.

When dissolving under pressure, equipment such as an autoclave with a stirrer can be used. As the shape of the stirring blade, a marine propeller blade, a paddle blade, an anchor blade, a turbine blade, or the like is used. When performing on a small scale, a magnetic stirrer or the like may be used.

(2) Precipitation step The solution obtained by dissolving the above fluorinated copolymer in the above-mentioned (1) dissolution step under the condition that the fluorinated copolymer is precipitated as fine particles in the solvent. A composition in which fine particles of the fluorine copolymer are precipitated in the solvent and the fine particles of the fluorine-containing copolymer are dispersed in the solvent is obtained. As the deposition condition, normal temperature and normal pressure are preferable.
As an example of a specific operation in the precipitation step, the fluorocopolymer fine particles are precipitated in the solvent by cooling the solution obtained in the dissolution step (1) to room temperature. In this case, the cooling method is not particularly limited, and may be slow cooling or rapid cooling.
Here, the composition refers to a mixture of a solvent and a fluorine-containing copolymer containing the fluorine-containing copolymer as fine particles.

As the dispersion state of the fluorine-containing copolymer fine particles in the composition obtained in the precipitation step, in addition to the case where the fine particles are uniformly dispersed in the solvent, a part or the whole of the solvent containing the fine particles is gelled. In some cases, the fine particles are unevenly distributed in the solvent and dispersed unevenly. The dispersion state like the latter appears more remarkably as the blending ratio of the fluorine-containing copolymer to the solvent is higher. In the case of such a non-uniform composition, the following crushing / dispersing steps are performed in order to obtain a fluororesin organosol having excellent handling properties in which the fine particles of the fluorine-containing copolymer are uniformly dispersed in the solvent. .

(3) Crushing / dispersing step In the crushing / dispersing step, a high shear force is applied to the composition of the fluorine-containing copolymer obtained in the above (2) precipitation step with the fine particles to form a solvent. This is a step of dispersing the fine particles of the fluorinated copolymer more uniformly.
Specific examples of methods for applying a high shear force to the mixture include high-speed rotation, high-pressure injection, high-speed vibration, ultrasonic treatment, and high-pressure filtration. Among these, a method using high-speed rotation, high-pressure injection, or high-speed vibration (hereinafter collectively referred to as “stirring”) is preferable because it is a simple method. Moreover, the method of applying these high shear forces may be performed alone, or two or more methods, for example, stirring and ultrasonic treatment may be used in combination.

As a device for applying a high shearing force to the mixture by stirring, a stirring device usually used for stirring a liquid material while applying a high shearing force can be used without any particular limitation. As such an agitator, an agitator having an agitating blade having a large shearing force among normal agitating blades such as a turbine blade and an edged turbine blade can be used in the crushing / dispersing step. Moreover, it is preferable to use the following stirring apparatus and dispersion apparatus which can obtain a higher shearing force. Conditions such as the number of revolutions, pressure, treatment time, treatment temperature, etc. when applying a high shear force to the mixture of the solvent and the fluorinated copolymer using a high shearing stirrer are determined depending on the state of the mixture and used. It is appropriately selected depending on the apparatus. Hereinafter, (a) to (c) and (e) are stirring devices by high-speed rotation, and (d) is a dispersing device by high-pressure injection.

(A) A stirrer represented by a TK homomixer (manufactured by Primix), Ultra Thalax (manufactured by IKA), polytron (manufactured by KINEMATICA) or the like, that is, a stirrer in which a stationary ring is combined in the vicinity of the outer periphery of a stirring blade. A device that rotates the rotor at high speed and enhances the atomization effect by using the powerful shearing effect and impact force generated in the minute gap between the stirring blade and the stationary ring; rotation when applying high shearing force Specific examples of the number include 1000 to 30000 rotations / minute.
(B) Stirring devices represented by Claremix (made by M Technique Co., Ltd.), that is, shearing force, collision force, pressure fluctuation, cavitation and potential core generated on the rotor rotating at high speed and the surrounding screen. Stirring device: Specific examples of the number of rotations when applying a high shear force include 1000 to 22000 rotations / minute.
(C) A stirrer represented by Cavitron (manufactured by Eurotech), DRS2000 (manufactured by IKA) or the like, that is, a stirrer provided with a comb-shaped rotor and a stator arranged concentrically. , A device for rotating the rotor at a high speed, causing a mixture to be stirred from the inside of the rotor to the outside of the stator, and stirring the mixture in the gap between the rotor and the stator; Specifically, the tip speed of the stirring blade is 2 to 50 m / sec.

(D) Dispersing device typified by Menton Gaulin homogenizer (manufactured by Gorin), that is, pressurizing the processing liquid with a high pressure plunger pump, etc. An apparatus that strikes and disperses at a high speed; specifically, the pressure when applying a high shearing force is 1 to 100 MPa.
(E) A stirrer typified by TK fill mix (manufactured by Primix), that is, the liquid mixture to be processed is pressed against the side wall of the dispersion tank by centrifugal force to form a liquid film, and the liquid film is rotated at an ultra high speed. A device that stirs by touching the tip of the stirrer; Specific examples of the tip speed of the stirring blade when high shear force is applied include 2 to 50 m / sec.

In order to apply a high shearing force to the above mixture by high pressure filtration, a commercially available high pressure filtration device that allows a liquid to pass through pores such as a filter at high pressure can be applied without particular limitation. In addition, specific conditions, for example, pressure, filter pore diameter, treatment time, treatment temperature, etc. when applying a high shear force to the mixture of the solvent and the fluorinated copolymer using a high-pressure filtration device are as follows: It is appropriately selected depending on the state of the mixture and the apparatus used. More specifically, conditions such as a pressure of 0.1 to 2.0 Mpa and a filter pore size of 0.1 to 5 μm can be mentioned.

In order to apply a high shear force to the mixture by ultrasonic treatment, a commercially available ultrasonic cleaner, ultrasonic transmitter, or the like can be used. Also in this case, specific conditions when applying a high shear force to the mixture of the solvent and the fluorinated copolymer, such as frequency, treatment time, treatment temperature, etc., are appropriately selected depending on the state of the mixture and the apparatus used. Is done. More specifically, the oscillation frequency includes conditions such as 10 to 200 kHz.
In addition, in the manufacturing method of this invention, you may perform said (2) precipitation process and (3) crushing and dispersion | distribution process simultaneously as needed.

Further, in order to disperse the fluorine-containing copolymer fine particles more uniformly in the solvent, a viscosity modifier (also referred to as “thickening agent”) is added to the (3) crushing / dispersing step of the production method of the present invention. It is preferable to carry out.
The viscosity modifier to be used is not particularly limited as long as it can reduce the viscosity of the mixture of the solvent and the fluorinated copolymer. Specifically, an alkyl group having 1 to 20 carbon atoms in which any —CH ₂ — other than the bonding terminal, which may be substituted with a halogen group, may be substituted with an oxygen atom, an amino group, an amide And a compound having at least one functional group selected from the group consisting of a group, a sulfonamide group, an imidazole group, a hydroxyl group and a mercapto group.

More specifically, as such a viscosity modifier, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecyl Amine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, icosylamine, 2-ethoxyethylamine, 3-butoxypropylamine, 2- (ethylamino) ethanol, 4-ethylamino-1-butanol, 2- (butylamino) ) Ethanol, 4- (butylamino) -1-butanol, octanamide, nonanamide, decanamide, dodecanamide, tridecanamide, tetradecanamide, pentadecanamide, hexadecanamide Heptadecanamide, octadecanamide, 1-octanesulfonamide, 1-nonanesulfonamide, 1-decanesulfonamide, 1-undecanesulfonamide, 1-dodecanesulfonamide, 1-tridecanesulfonamide, 1-tetradecanesulfonamide, 1-pentadecane sulfonamide, 1-hexadecane sulfonamide, 1-heptadecane sulfonamide, 1-octadecane sulfonamide, 2-butylimidazole, 2-pentylimidazole, 2-hexylimidazole, 2-heptylimidazole, 2-octylimidazole, 2-nonylimidazole, 2-decylimidazole, 2-undecylimidazole, 2-dodecylimidazole, 2-tridecylimidazole, 2-tetradecylimidazole, 2-pen Decylimidazole, 2-hexadecylimidazole, 2-heptadecylimidazole, 2-octadecylimidazole, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-octanethiol, 1-nonanethiol, 1-decanethiol, 1-undecanethiol, 1-dodecanethiol, 1 -Tridecanethiol, 1-tetradecanethiol, 1-pentadecanethiol, 1-hexadecanethiol, 1-heptadecanethiol, 1-octadecanethiol and the like. Among these, 3-butoxypropylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine and the like are preferable. . These can be used alone or in combination of two or more.

The amount of the viscosity modifier used is preferably from 0.1 to 20% by mass, more preferably from 0.5 to 10% by mass, based on the fluorine-containing copolymer in the mixture. The amount of the viscosity modifier is a total amount with other optional components, and is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total amount of the fluororesin organosol. Further, the timing of adding the viscosity modifier is not particularly limited as long as it is before the (3) crushing / dispersing step. For example, you may add in said (1) melt | dissolution process, and may add after said (2) precipitation process. However, when adding after a precipitation process, it is preferable to perform sufficient stirring with a ball mill etc. so that a viscosity modifier may exist uniformly in the mixture of the said solvent and a fluorine-containing copolymer.
In the thus obtained dispersion of the fluorinated copolymer, coarse aggregated particles may remain. For the purpose of removing such agglomerated particles, a step of filtering the dispersion may be performed. As a filtration method, any method such as pressure filtration, vacuum suction filtration, and normal pressure natural filtration may be used. As a filtration method, pressure filtration is preferable, and as a filter medium, a stainless steel filter or a resin filter can be used.
Thus, by the production method of the present invention, a fluororesin in which the fine particles of the fluorine-containing copolymer are dispersed in the solvent, and the fine particles of the fluorine-containing copolymer are uniformly dispersed in the solvent. An organosol is obtained.

[Fluoro resin organosol]
In the fluororesin organosol obtained by the production method of the present invention (hereinafter referred to as the fluororesin organosol of the present invention), the fine particles of the fluorocopolymer are uniformly dispersed in the dispersion medium using the solvent as a dispersion medium. It exists in a distributed state. In the fluororesin organosol of the present invention, the average particle diameter of the fluorine-containing copolymer fine particles is preferably 0.005 to 5 μm as the number average particle diameter measured by a dynamic light scattering method at 25 ° C., 0.005 ˜2 μm is more preferable, and 0.01 to 1 μm is most preferable. Here, the number average particle diameter is a particle diameter in which the ratio of the number of particles having a smaller particle diameter is equal to the number of particles having a larger particle diameter than the average particle diameter obtained.

In the fluororesin organosol of the present invention, if the average particle size of the fluorine-containing copolymer fine particles is in the above range, for example, when this is used as a coating composition, it is homogeneous, transparent, flat, and adherent. A coating film excellent in properties can be formed. Unless otherwise specified, in this specification, the average particle diameter means the average primary particle diameter.

[Coating composition]
The coating composition of the present invention is a coating composition containing the fluororesin organosol of the present invention as a main component. The coating composition of the present invention is a fluororesin organosol consisting of the fluorocopolymer fine particles and the solvent alone, or a fluororesin organosol containing the fluorocopolymer microparticles and the solvent and an optional component. . Moreover, what added arbitrary components to such a fluororesin organosol may be used.

The coating composition of the present invention contains, as an essential component, an organosol formed by the fine particles of the fluorine-containing copolymer and a solvent satisfying the above conditions. Furthermore, other optional components can be contained as necessary within a range not impairing the effects of the present invention. Examples of such optional components include antioxidants, light stabilizers, ultraviolet absorbers, crosslinking agents, lubricants, plasticizers, thickeners, dispersion stabilizers, fillers, fillers, reinforcing agents, pigments, dyes And various additives such as flame retardants and antistatic agents. Moreover, as content of an arbitrary component, 30 mass% or less is preferable with respect to the coating composition whole quantity, and 10 mass% or less is more preferable.
Moreover, when using the coating composition of this invention as a coating material, you may mix a non-fluororesin like it is performed with the general fluorine coating material.

The optional component may be added to the raw material component in the (1) dissolution step of the fluororesin organosol production process, or may be added to the fluororesin organosol consisting only of the fluorocopolymer fine particles and the solvent. . In addition, when a plurality of optional components are added, some of the optional components are added to the raw material components in the above (1) dissolving step to produce a fluororesin organosol, and then the same or different types of fluororesin organosol are used. Optional ingredients may be added.

Formation of the fluorine-containing copolymer coating film on the substrate by the coating composition of the present invention can be performed by the following coating film forming method.
The coating composition of the present invention is applied to a substrate to form a solvent-containing coating film, and the solvent removal step is performed to remove the solvent from the solvent-containing coating film to form a solvent-free coating film. Thereby, the coating film of a fluorine-containing copolymer can be obtained simply from the coating composition of this invention.

(Coating process)
In the coating step of the coating film forming method using the coating composition of the present invention, the means used for coating the coating composition on the substrate is not particularly limited, and generally used methods can be used. Examples of the application method include gravure coating, dip coating, die coating, spray coating, electrostatic coating, brush coating, screen printing, roll coating, spin coating, and the like.

In the coating step, the coating composition of the present invention does not necessarily have to be applied in a state where the fluorine-containing copolymer is dissolved in the solvent. The coating composition of the present invention is characterized in that the fluorine-containing copolymer is uniformly dispersed in the solvent even at a temperature below the temperature at which the fluorine-containing copolymer dispersed in the solvent dissolves. Therefore, in the coating step, the coating composition of the present invention is applied to the substrate at a temperature lower than the temperature at which the fluorine-containing copolymer is dissolved in the solvent, and the solvent is heated at a relatively low temperature described below. Can be removed (dried). Application in this way is preferable from the following viewpoints and workability. In the method for forming a coating film using the coating composition of the present invention, a dense and flat coating film can be obtained by adjusting the coating temperature and the drying temperature to such a low temperature.

The coating temperature in the coating step varies depending on the coating composition to be used, but is preferably 0 to 210 ° C, more preferably 0 to 130 ° C, and most preferably 0 to 50 ° C. If the coating temperature is less than 0 ° C., the dispersion state of the fluorine-containing copolymer is not sufficient, and if it exceeds 210 ° C., the contained solvent tends to volatilize and bubbles may be generated, which is not preferable. .

(Solvent removal step)
The said solvent removal process is a process of removing a solvent from the solvent containing coating film obtained at the said application | coating process, and setting it as the coating film which does not contain a solvent.
The solvent removal temperature in the solvent removal step, that is, the drying temperature is preferably 0 to 350 ° C, more preferably 10 to 270 ° C, and most preferably 20 to 240 ° C.
If the temperature at the time of solvent removal (drying temperature) is less than 0 ° C, it takes too much time to remove the solvent, and if it exceeds 350 ° C, coloring or decomposition may occur, which is not preferable.
It is also preferable to heat-treat at 40 to 350 ° C. after forming a coating film using the coating composition. The heat treatment temperature is more preferably 70 to 270 ° C, and most preferably 100 to 250 ° C. By performing the heat treatment, the coating film becomes denser and the adhesion to the substrate can be enhanced. Thereby, durability improves and it can protect a base material more effectively.

Thus, in the method for forming a coating film of a fluorinated copolymer using the coating composition of the present invention, it is not necessary to apply and dry the coating composition at a high temperature. Therefore, a coating film can be formed even on materials having low heat resistance such as plastic, paper, and cloth without causing decomposition or deformation of the substrate.

The material and shape of the substrate coated with the fluorine-containing copolymer are not particularly limited, and metals such as iron, stainless steel, aluminum, titanium, copper, and silver, glass such as window glass, mirror, and synthetic quartz are used. , Silicon, polycarbonate (PC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), glass fiber reinforced plastic (FRP), polyvinyl chloride (PVC), organic materials such as fluororesin, stone, wood, ceramics, Can be applied to cloth, paper, etc.

Here, in the method for forming a coating film of a fluorinated copolymer using the coating composition of the present invention, the base material is pretreated for the purpose of improving the adhesion between the base material and the coating film. Also good. For example, a silane coupling agent, polyethyleneimine, or the like can be applied to the substrate, the surface can be physically treated by sandblasting, or treatment by corona discharge or the like can be performed.

By coating the coating composition mainly composed of the fluororesin organosol obtained by the production method of the present invention on the substrate in this way, the coating film of the fluorinated copolymer and the coating film Coated articles can be provided.

Also, the coating film of the fluorine-containing copolymer obtained by the method for forming a coating film can be used as a film-like molded body by separating from the base material. The thus obtained fluorine-containing copolymer, that is, the ETFE film, is thinner and more uniform than an ETFE film obtained by general melt molding.

The thickness of the obtained coating film or film-like molded product can be freely selected according to the purpose. If a high concentration solution or dispersion is used, a thick film can be obtained, and if a low concentration solution or dispersion is used, a thin coating can be obtained. Moreover, a thicker film can be obtained by repeating the coating process a plurality of times.

Since it has the above-mentioned features, the application of the coating composition mainly composed of the fluororesin organosol of the present invention includes an optical fiber clad material, a lens, an article for solar cell, an article for display panel / display, an optical disk, Semiconductors, hybrid ICs, liquid crystal cells, printed circuit boards, IC cards, photosensitive drums, film capacitors, glass windows, resin windows, various films, various sensors, antennas, covered wires, motors, power generation devices, etc. Protective coating agent in the field, water repellent coating agent, low reflection coating agent, electrically insulating coating material, charge retention layer, trains, buses, trucks, automobiles, ships, aircraft and other transportation equipment articles, outer walls, roofing materials, Sealant parts, building articles such as bridges and tunnels, syringes, pipettes, thermometers, beakers, shears , Medical cylinders, chemicals, other solder masks, solder resists, rubber, plastic protection, weather resistance, antifouling coating, fiber, fabric protective coating, sealant antifouling coating, IC sealing Examples of the stopper include rust preventive paints, resin adhesion inhibitors, ink adhesion inhibitors, articles for separation membranes, primers for laminated steel sheets, various adhesives, and binders.

Examples of the solar cell article include a protective cover material made of glass or resin, a transparent conductive member, a protective coating agent such as a backsheet, a gas barrier layer, a thin glass support resin layer, and an adhesive layer.

Examples of the display panel / display article include liquid crystal display panels, plasma display panels, electrochromic display panels, electroluminescent display panels, protective coating agents for transparent members (glass substrates and resin substrates) used in touch panels, and antifouling coating agents. , Low reflection coating agents, thin glass support resins, and the like.

As the above-mentioned articles for transport equipment, exterior members such as display device surface materials mounted on transport equipment, interior members such as instrument panel surface materials, protective coating agents such as bodies and mirrors, antifouling coating agents, and low reflection coating agents And laminated materials for safety glass.
Examples of the separation membrane article include functional layers such as reverse osmosis membranes and nanofiltration membranes, functional layers of gas separation membranes that separate carbon dioxide, hydrogen, etc., adhesives in membrane module production, antifouling coating agents, and the like. .

Further, the coating composition of the present invention can be advantageously used as a material composition for producing an interlayer insulating film and a protective film in semiconductor elements and integrated circuit devices. If the coating composition mainly composed of the fluororesin organosol of the present invention is used for such applications, the response speed utilizing the characteristics such as low water absorption, low dielectric constant and high heat resistance of the fluorine-containing copolymer can be obtained. A semiconductor element integrated circuit device can be obtained quickly and with few malfunctions.

Further, the coating composition of the present invention is advantageous for a protective coating agent for a condensing mirror used in concentrating solar power generation, an antifouling coating agent, a protective coating agent for a sealing part such as a backing resin of the condensing mirror, and the like. Can be used. If the coating composition mainly composed of the fluororesin organosol of the present invention is used for such applications, the power generation system that is highly durable and does not require maintenance due to the high heat resistance and low water absorption characteristics of the fluororesin. Can be obtained.
Moreover, the fluororesin organosol of the present invention can be used for applications such as adhesives, binders, and toner additives in addition to coating applications.

Examples of the present invention will be described below, but the present invention is not limited thereto.
(Dissolution procedure)
Examples and Comparative Examples shown below were carried out by the following methods unless otherwise specified.
A fluorine-containing copolymer, a solvent and a stirrer were placed in a pressure resistant reaction vessel made of borosilicate glass having a wall thickness of 4 mm and an outer diameter of 30 mm. The relative amount of the fluorinated copolymer and the solvent was set to 5 to 10% by mass as the amount of the fluorinated copolymer relative to the amount of the solvent.
The reaction vessel was heated using a well stirred and temperature controlled oil bath.
Whether or not the fluorine-containing copolymer was dissolved was determined by visual observation. If the content of the test tube was a transparent and uniform solution, it was determined as a dissolved state.

(Fine particle dispersion, coating film evaluation method)
The fine particle dispersions obtained in the examples and the coating film were evaluated for the following items by the following method.
(1) Number average particle diameter The number average particle diameter of the ETFE fine particles in the dispersion is measured by a dynamic light scattering method using a particle size distribution measuring device (Nanotrac manufactured by Microtrac) under a temperature condition of 25 ° C. did. In addition, the primary particle diameter of the ETFE fine particles was observed with a transmission electron microscope (TEM) (JEM-1230 manufactured by JEOL Ltd.), and the results obtained by the dynamic light scattering method were confirmed. confirmed.

(2) Film thickness About the coating film obtained by potting and bar coater, the coating film obtained by a method other than the above using a stylus type surface shape measuring instrument (Sloan, DEKTAK 3ST) The film thickness was measured with a contact optical thin film measuring apparatus (Filmtrics F-20, manufactured by Filmetrics).

(3) Adhesion The adhesion test was performed in accordance with JIS-K-5600 (1999). That is, 11 straight cuts with a 2 mm interval were made on the fluorine-containing copolymer thin film on the substrate using a cutter knife to make 100 grids, and cellophane adhesive tape was strongly pressure-bonded on the grids. The end of this tape was held and peeled off instantaneously, and the state of the thin film remaining without being peeled on the surface of the skin was observed. Evaluation was made based on the state of peeling after five peeling tests. The case where 91 squares or more are adhered is indicated by ○ (excellent), the case where 90-51 squares are adhered is indicated by △ (normal), and the case where 50-0 squares are adhered is indicated by × (defective).

[Example 1]
In a 30 mL borosilicate glass pressure-resistant reaction vessel, as a fluorine-containing copolymer, ETFE (molar ratio of repeating units based on constituent monomers: repeating units based on tetrafluoroethylene / repeating units based on ethylene / 3, 3, 3, Repeating unit based on 4,4,4-pentafluoro-1-butene / repeating unit based on itaconic anhydride = 57.5 / 39.9 / 2.3 / 0.3, melting point: 240 ° C., hereinafter “ETFE1 ) And 0.85 g of diisopropyl ketone (R calculated by the above formula (1) (hereinafter simply referred to as “R”) = 0) and heated to 185 ° C. with stirring. As a result, a uniform and transparent solution was obtained.

When the test tube was gradually cooled to room temperature, a uniform fluorine-containing copolymer gel (the concentration of ETFE 1 was 5% by mass) was obtained. This gel-like product was stirred for 2 minutes at 30 m / sec using a TK film mix type 40-40 manufactured by Primics to obtain a uniform dispersion (fluororesin organosol of the present invention). The average particle size of the fine particles of the fluorinated copolymer was 58 nm as the number average particle size measured by a dynamic light scattering method at 25 ° C.

Further, when this dispersion was diluted to 0.05% by mass and observed with a transmission electron microscope, it was confirmed that the primary particle diameter was 40 to 50 nm. FIG. 1 shows a transmission electron microscope (TEM) photograph (100,000 times).
In TEM photography, since the solvent in the dispersion is removed at the time of sample preparation, in the resulting photograph, for example, the fluorine-containing copolymer particles form aggregated particles as shown in the photograph in FIG. it is conceivable that. When the photograph of FIG. 1 is observed, it can be seen that there is one large aggregate particle in the photograph, and each of the aggregate particles is formed by a collection of many smaller particles. The aggregated particles are ETFE1 aggregated particles, and the individual particles constituting the aggregated particles are primary ETFE1 particles. The observed number average particle size means that the primary particles of ETFE1 that have identified the photographic particles in this way are present alone in the dispersion or as secondary particles formed by collecting several primary particles. The particle diameter of the particles corresponding to 50% of the total number of particles.

The dispersion was applied on a glass substrate (crown glass, thickness 1 mm) with a bar coater at room temperature and dried at room temperature. Heating was performed on a hot plate at 180 ° C. for 3 minutes to obtain a glass substrate having a ETFE1 thin film formed on the surface. When the surface of the obtained thin film was observed with an optical microscope (100 times), it was confirmed to be a uniform and smooth film. FIG. 2 shows an optical micrograph (100 times) of the surface of the thin film made of ETFE1. Moreover, it was 3 micrometers when the film thickness was measured with the stylus type surface shape measuring device. When the adhesion of the obtained ETFE1 film was evaluated, no peeling was observed. That is, the evaluation of adhesion was ○ (excellent).

[Example 2]
The fluororesin organosol obtained in Example 1 was coated on a PET (polyethylene terephthalate) film (Cosmo Shine (registered trademark) A4300 manufactured by Toyobo Co., Ltd .; thickness: 100 μm) with a bar coater at room temperature and dried at room temperature. It heated for 3 minutes on a 100 degreeC hotplate, and the thin film of ETFE1 was formed on PET film. Moreover, it was 3 micrometers when the film thickness was measured with the stylus type surface shape measuring device. When the adhesion of the obtained ETFE1 film to the PET film was evaluated, no peeling was observed. That is, the evaluation of adhesion was ○ (excellent).

[Example 3]
The fluororesin organosol obtained in Example 1 was coated on an aluminum plate (thickness: 200 μm) with a bar coater at room temperature, dried, and then heated on a hot plate at 230 ° C. for 3 minutes to form ETFE1 on the aluminum plate. A thin film was formed. When the adhesion between the obtained ETFE1 film and the aluminum plate was evaluated, no peeling was observed. That is, the evaluation of adhesion was ○ (excellent).

[Example 4]
A uniform fluorine-containing copolymer gel (concentration of ETFE1 of 10% by mass) in the same manner as in Example 1 except that 1.60 g of ETFE1 and 14.4 g of diisopropyl ketone are used as the fluorine-containing copolymer. Got. To this gel was added dodecylamine (0.03 g) as a viscosity modifier, and the mixture was stirred for 10 minutes at 2000 rpm with a planetary ball mill (Shinky Corporation, Awatori Nertaro ARE-310). The obtained slurry was stirred for 2 minutes at 30 m / sec using a TK film mix type 40-40 manufactured by Primics, to obtain a uniform dispersion (fluororesin organosol of the present invention). Using this dispersion, a glass substrate having a ETFE1 thin film formed on the surface thereof was obtained in the same manner as in Example 1. When the obtained ETFE1 film was observed with an optical microscope, it was confirmed to be a uniform and smooth film. Moreover, it was 6 micrometers when the film thickness was measured with the stylus type surface shape measuring device. When the adhesion of the obtained ETFE1 film was evaluated, no peeling was observed. That is, the evaluation of adhesion was ○ (excellent).

[Example 5]
In the same manner as in Example 1, a uniform gel-like product of ETFE 1 (the concentration of ETFE 1 was 5% by mass) was obtained. This gel-like product was stirred for 5 minutes at 22,000 rpm using a Polytron PT10-35 type manufactured by KINEMATICA to obtain a uniform dispersion (fluororesin organosol of the present invention).
A glass substrate having a ETFE 1 thin film formed on the surface of the dispersion was obtained in the same manner as in Example 1. When the surface of the obtained ETFE1 film was observed with an optical microscope, it was confirmed that the film was uniform and smooth.

(Chemical resistant protective coating)
[Example 6]
The aluminum substrate coated with ETFE1 obtained in Example 3 (aluminum substrate with protective coating) was immersed in 1N hydrochloric acid, and the change was observed. The results are shown in Table 1 together with the results obtained by similarly treating an aluminum substrate without a protective coat.

As shown in Table 1, the chemical resistance of the aluminum plate could be remarkably improved by coating the fluororesin organosol of the present invention.

When the fluororesin organosol of the present invention is used as a coating composition, it is easy to form an ETFE coating film by coating, and has heat resistance, flame resistance, chemical resistance, weather resistance, low friction, low dielectric constant. Suitable for applications such as surface treatment that require properties and transparency.
The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2010-198288 filed on September 3, 2010 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (13)

1. A fluorine-containing copolymer having a repeating unit based on ethylene and a repeating unit based on tetrafluoroethylene is used as a dispersoid, and a solvent capable of dissolving the fluorine-containing copolymer at a temperature below the melting point of the fluorine-containing copolymer. A method for producing a fluororesin organosol as a dispersion medium,
   A dissolution step of dissolving the fluorine-containing copolymer in the solvent to form a solution;
   A precipitation step of precipitating the fluorine-containing copolymer as fine particles in the solvent in the solution;
   A crushing / dispersing step of uniformly dispersing fine particles of the fluorinated copolymer in the solvent by applying a high shear force to the mixture of the solvent and the fluorinated copolymer containing the fluorinated copolymer as fine particles. A process for producing a fluororesin organosol, comprising:
2. The method for producing a fluororesin organosol according to claim 1, wherein the precipitation step and the crushing / dispersing step are performed simultaneously.
3. The fluororesin organosol according to claim 1 or 2, wherein the high shear force is applied by at least one method selected from the group consisting of high-speed rotation, high-pressure jetting, high-speed vibration, ultrasonic treatment, and high-pressure filtration. Production method.
4. The method for producing a fluororesin organosol according to any one of claims 1 to 3, wherein the dissolution is performed at a temperature of 40 ° C or higher and below the melting point of the fluorine-containing copolymer, and the precipitation is performed by cooling.
5. 2. The blending ratio of the fluorinated copolymer and the solvent in the dissolving step is 1.0: 99.0 to 70.0: 30.0 in a mass ratio represented by the fluorinated copolymer: solvent. 5. The method for producing a fluororesin organosol according to any one of items 1 to 4.
6. 6. The fluororesin organosol according to claim 1, wherein a solubility index (R) for the fluorine-containing copolymer based on a Hansen solubility parameter represented by the following formula (1) in the solvent is less than 25. Manufacturing method.
   R = 4 × (δd−15.7) ² + (δp−5.7) ² + (δh−4.3) ² (1)
   (In the formula (1), δd, δp, and δh respectively represent a dispersion term, a polar term, and a hydrogen bond term in the Hansen solubility parameter.)
7. The average particle diameter of the fluorine-containing copolymer fine particles is in a range of 0.005 to 5 μm as a number average particle diameter measured by a dynamic light scattering method at 25 ° C. The manufacturing method of the fluororesin organosol as described in a term.
8. The method for producing a fluororesin organosol according to any one of claims 1 to 7, wherein the high shear force is applied in the presence of a viscosity modifier.
9. The viscosity modifier may be substituted with a halogen group, and an arbitrary —CH ₂ — other than the bond terminal may be substituted with an oxygen atom, an amino group, an amide group The method for producing a fluororesin organosol according to any one of claims 1 to 8, which is a compound having at least one functional group selected from the group consisting of a sulfonamide group, a hydroxyl group and a mercapto group.
10. The proportion of repeating units based on comonomer other than tetrafluoroethylene and ethylene constituting the fluorine-containing copolymer is 0.1 to 50 mol%, according to any one of claims 1 to 9. Of manufacturing fluororesin organosols.
11. 11. The fluorine-containing copolymer according to claim 1, wherein the fluorine-containing copolymer is at least one selected from the group consisting of a carboxylic acid group, an acid anhydride group, and a carboxylic acid halide group. A method for producing a fluororesin organosol as described in 1.
12. A fluororesin organosol obtained by the production method according to any one of claims 1 to 11.
13. A coating composition comprising as a main component a fluororesin organosol obtained by the production method according to any one of claims 1 to 11.

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