CN116769364A - Coating composition, coating film, laminated coating film, and coated article - Google Patents

Coating composition, coating film, laminated coating film, and coated article Download PDF

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Publication number
CN116769364A
CN116769364A CN202210234615.5A CN202210234615A CN116769364A CN 116769364 A CN116769364 A CN 116769364A CN 202210234615 A CN202210234615 A CN 202210234615A CN 116769364 A CN116769364 A CN 116769364A
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Prior art keywords
mass
coating composition
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ptfe
group
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CN202210234615.5A
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Chinese (zh)
Inventor
吴琮祺
饶宝云
木下琢哉
城丸智洋
西村启
中谷安利
加藤丈人
山本绘美
山部拓也
山中拓
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Dajin Fluorine Coating (Shanghai) Co Ltd
Daikin Industries Ltd
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Dajin Fluorine Coating (Shanghai) Co Ltd
Daikin Industries Ltd
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Application filed by Dajin Fluorine Coating (Shanghai) Co Ltd, Daikin Industries Ltd filed Critical Dajin Fluorine Coating (Shanghai) Co Ltd
Priority to CN202210234615.5A priority Critical patent/CN116769364A/en
Priority to TW112108809A priority patent/TW202348750A/en
Priority to PCT/JP2023/009181 priority patent/WO2023171777A1/en
Publication of CN116769364A publication Critical patent/CN116769364A/en
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/22—Emulsion polymerisation
    • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
    • C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
    • C08F214/18—Monomers containing fluorine
    • C08F214/26—Tetrafluoroethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F216/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
    • C08F216/12—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an ether radical
    • C08F216/14—Monomers containing only one unsaturated aliphatic radical
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F259/00—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00
    • C08F259/08—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00 on to polymers containing fluorine
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
    • C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
    • C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
    • C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
    • C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C09D127/18—Homopolymers or copolymers of tetrafluoroethene
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D151/00—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/65—Additives macromolecular

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Paints Or Removers (AREA)
  • Laminated Bodies (AREA)

Abstract

The invention provides a coating composition, a coating film, a laminated coating film and a coated article, and provides a coating composition capable of obtaining a coating film with excellent abrasion resistance, and a coating film, a laminated coating film and a coated article using the same. A coating composition comprising a fluorine-containing ethylenic polymer, a filler, and water, wherein the content of the fluorine-containing ethylenic polymer is 1 to 50% by mass relative to the coating composition, and the filler is at least one selected from the group consisting of: (i) 0.1 to 80 mass% of a filler having a new mohs hardness of 9 or more relative to the fluoroethylene-based polymer; (ii) 0.1 to 120 mass% of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluoroethylene-based polymer; and (iii) 1 to 150 mass% of a filler having a new mohs hardness of less than 5 relative to the fluorine-containing ethylenic polymer.

Description

Coating composition, coating film, laminated coating film, and coated article
Technical Field
The present disclosure relates to a coating composition, a coating film, a laminated coating film, and a coated article.
Background
A technique of using an aqueous polytetrafluoroethylene dispersion for a coating material is known (for example, refer to patent documents 1 and 2).
Prior art literature
Patent literature
Patent document 1: international publication No. 2021/045228
Patent document 2: japanese patent laid-open No. 2000-238205
Disclosure of Invention
Problems to be solved by the invention
The purpose of the present disclosure is to provide a coating composition capable of providing a coating film having excellent abrasion resistance, and a coating film, a laminated coating film, and a coated article using the coating composition.
Means for solving the problems
The present disclosure provides a coating composition comprising a fluoroethylene-based polymer, a filler material, and water, wherein,
the content of the fluorine-containing ethylenic polymer is 1 to 50% by mass relative to the coating composition,
the filler is at least one selected from the group consisting of:
(i) 0.1 to 80 mass% of a filler having a new mohs hardness of 9 or more relative to the fluoroethylene-based polymer;
(ii) 0.1 to 120 mass% of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluoroethylene-based polymer; and
(iii) 1 to 150 mass% of a filler having a new mohs hardness of less than 5 relative to the fluoroethylene-based polymer.
In one embodiment of the coating composition, the filler is preferably at least one selected from the group consisting of:
(i-1) 0.1 to 15 mass% of a filler having a new mohs hardness of 9 or more relative to the fluorine-containing ethylenic polymer; and
(ii-1) 0.1 to 20 mass% of a filler having a new Mohs hardness of 5 or more and less than 9 relative to the fluorine-containing ethylenic polymer.
In the above aspect, the coating composition preferably does not contain a heat-resistant resin (excluding the fluoroethylene-based polymer).
In the above aspect, the content of the fluorine-containing ethylenic polymer is preferably 15 mass% or more with respect to the coating composition.
In the above aspect, the content of the fluorine-containing ethylenic polymer is preferably 49 mass% or less with respect to the coating composition.
In the above aspect, the viscosity of the coating composition at 25℃is preferably 10 mPas to 1000 mPas.
In another embodiment of the coating composition, the coating composition preferably further comprises a heat-resistant resin (excluding the fluoroethylene-based polymer).
In the above aspect, the content of the fluorine-containing ethylenic polymer is preferably 1 to 30% by mass relative to the coating composition.
In the above aspect, the viscosity of the coating composition at 25℃is preferably 50 mPas to 1500 mPas.
The fluoroethylene-based polymer preferably contains polytetrafluoroethylene.
The content of polytetrafluoroethylene is preferably 50 mass% or more with respect to the fluorine-containing ethylenic polymer.
The gelation time of the above-mentioned coating composition in the stirring stability test is preferably 4 hours or more.
The number of applications of the coating composition to the occurrence of white spots in the continuous spray coatability test is preferably 100 or more.
The present disclosure also provides a coating formed from the above coating composition.
The present disclosure also provides a laminated film comprising the above film.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present disclosure, it is possible to provide: a coating composition which can provide a coating film having excellent abrasion resistance; and a coating film, a laminated coating film and a coated article using the coating composition.
Detailed Description
The present disclosure is specifically described below.
The present disclosure provides a coating composition comprising a fluoroethylene-based polymer, a filler, and water, wherein the content of the fluoroethylene-based polymer is 1 to 50% by mass relative to the coating composition, and the filler is at least one selected from the group consisting of: (i) 0.1 to 80 mass% of a filler having a new mohs hardness of 9 or more relative to the fluoroethylene-based polymer; (ii) 0.1 to 120 mass% of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluoroethylene-based polymer; and (iii) 1 to 150 mass% of a filler having a new mohs hardness of less than 5 relative to the fluorine-containing ethylenic polymer.
The coating composition of the present disclosure can provide a coating film excellent in abrasion resistance.
In addition, the coating composition of the present disclosure is less likely to cause clogging of a coating gun and white spots of a coating film during coating.
In addition, the coating composition of the present disclosure is also excellent in stirring stability (less prone to gelation).
Examples of the fluoroethylene-based polymer include Polytetrafluoroethylene (PTFE) and melt-processible fluororesin, and 1 or 2 or more kinds of the fluoroethylene-based polymers may be used.
The PTFE may be a homopolymer of Tetrafluoroethylene (TFE), or may be modified PTFE including a polymerized unit (TFE unit) based on TFE and a polymerized unit (modified monomer unit) based on a modified monomer. The modified PTFE may contain 99.0 mass% or more of polymerized units based on TFE and 1.0 mass% or less of polymerized units based on a modifying monomer. The modified PTFE may contain only TFE units and modified monomer units. The modified PTFE is preferable in view of excellent appearance of the obtained coating film.
In the modified PTFE, the content of the modified monomer unit is preferably in the range of 0.00001 to 1.0 mass%.
The lower limit of the content of the modified monomer unit is more preferably 0.0001 mass%, still more preferably 0.001 mass%, still more preferably 0.005 mass%, still more preferably 0.010 mass%, still more preferably 0.030 mass%, still more preferably 0.050 mass%, still more preferably 0.070 mass%, still more preferably 0.10 mass%, still more preferably 0.15 mass%, particularly preferably 0.20 mass%, and most preferably 0.25 mass%.
The upper limit of the content of the modified monomer unit is preferably 0.90 mass%, more preferably 0.50 mass%, still more preferably 0.45 mass%, still more preferably 0.40 mass%, particularly preferably 0.35 mass%, and most preferably 0.30 mass%.
In the present specification, the modified monomer unit refers to a part derived from a modified monomer as a part of the molecular structure of PTFE.
In the present specification, the content of each monomer constituting PTFE can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the types of monomers.
The modifying monomer is not particularly limited as long as it can be copolymerized with TFE, and examples thereof include perfluoroolefins such as hexafluoropropylene [ HFP ]; hydrofluoroolefins such as trifluoroethylene and vinylidene fluoride [ VDF ]; perhaloolefins such as chlorotrifluoroethylene; perfluorovinyl ether: perfluoro allyl ether; (perfluoroalkyl) ethylene, and the like. The number of the modifying monomers used may be 1 or 2 or more.
The perfluorovinyl ether is not particularly limited, and examples thereof include the general formula (a):
CF 2 ＝CF-ORf (A)
(wherein Rf represents a perfluorinated organic group) and the like. In the present specification, the term "perfluorinated organic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms. The perfluorinated organic group may have ether oxygen.
As the perfluorovinyl ether, for example, there may be mentioned perfluoro (alkyl vinyl ether) wherein Rf in the general formula (A) is a perfluoroalkyl group having 1 to 10 carbon atoms [ PAVE ]. The number of carbon atoms of the perfluoroalkyl group is preferably 1 to 5.
Examples of the perfluoroalkyl group in PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group.
The perfluorovinyl ether may further be one wherein Rf in the general formula (A) is a perfluoro (alkoxyalkyl) group having 4 to 9 carbon atoms, and Rf is the following formula:
[ chemical 1]
(wherein m represents 0 or an integer of 1 to 4), and Rf is represented by the following formula:
[ chemical 2]
(wherein n represents an integer of 1 to 4), and the like.
The (perfluoroalkyl) ethylene (PFAE) is not particularly limited, and examples thereof include (perfluorobutyl) ethylene (PFBE) and (perfluorohexyl) ethylene.
Examples of the perfluoroallyl ether include
A general formula: CF (compact flash) 2 ＝CF-CF 2 -ORf 11
(wherein Rf 11 Represents a perfluorinated organic group).
The Rf described above 11 A perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms is preferable. The perfluoroallyl ether is preferably selected from the group consisting of CF 2 ＝CF-CF 2 -O-CF 3 、CF 2 ＝CF-CF 2 -O-C 2 F 5 、CF 2 ＝CF-CF 2 -O-C 3 F 7 CF (compact flash) 2 ＝CF-CF 2 -O-C 4 F 9 At least one selected from the group consisting of CF, more preferably 2 ＝CF-CF 2 -O-C 2 F 5 、CF 2 ＝CF-CF 2 -O-C 3 F 7 CF (compact flash) 2 ＝CF-CF 2 -O-C 4 F 9 At least one of the group consisting of CF is further preferred 2 ＝CF-CF 2 -O-CF 2 CF 2 CF 3 。
The modified monomer may be a cyclic monomer. As cyclic monomer, the following general formula (ii) is preferred:
[ chemical 3]
(wherein X is 2 And X 3 Identical or different, represents a hydrogen atom or a fluorine atom, Y represents-CR 1 R 2 -，R 1 And R is 2 The same or different, and represents a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms). As the vinyl heterocyclic compound represented by the above general formula (ii), for example, X is preferable 2 And X 3 Is a fluorine atom, and preferably R 1 And R is 2 Is a fluoroalkyl group having 1 to 6 carbon atoms.
As the vinyl heterocyclic compound represented by the above general formula (ii), X is preferable 2 And X 3 Is a fluorine atom, R 1 And R is 2 Perfluoro-2, 2-dimethyl-1, 3-dioxole [ PDD ] being a perfluoromethyl group]。
The modifying monomer is preferably at least one selected from the group consisting of PAVE, PFAE, and the cyclic monomer, in view of transparency of the coating film.
The modified monomer may preferably have a monomer reactivity ratio of 0.1 to 8 (hereinafter referred to as "modified monomer (3)"). By the presence of the modifying monomer (3), PTFE particles having a small particle diameter can be obtained, and an aqueous dispersion having high dispersion stability can be obtained.
Here, the monomer reactivity ratio in copolymerization with TFE means a value obtained by dividing a rate constant at which a grown radical reacts with TFE by a rate constant at which the grown radical reacts with a modified monomer when the grown radical is less than a repeating unit based on TFE. The lower this value, the higher the reactivity of the modifying monomer with TFE. TFE can be copolymerized with a modifying monomer to determine the composition of the resulting polymer immediately after the start of copolymerization, and the monomer reactivity ratio can be calculated by the Finerman-Ross formula.
The copolymerization was carried out in a stainless steel autoclave having an internal volume of 6.0L using 3600g of deionized and degassed water, 1000ppm of ammonium perfluorooctanoate relative to the water, and 100g of paraffin wax at a pressure of 0.78MPa and a temperature of 70 ℃. To the reactor, 0.05g, 0.1g, 0.2g, 0.5g and 1.0g of a modified monomer were added, and 0.072g of ammonium persulfate (20 ppm relative to water) was added, and TFE was continuously fed so as to maintain the polymerization pressure of 0.78 MPa. After the TFE charge reached 1000g, stirring was stopped and the pressure was removed until the reactor reached atmospheric pressure. After cooling, the paraffin wax is separated, whereby an aqueous dispersion containing the resulting polymer is obtained. The aqueous dispersion was stirred to precipitate a polymer, and dried at 150 ℃. The composition of the resulting polymer was calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the kind of monomer.
The modified monomer (3) having a monomer reactivity ratio of 0.1 to 8 is preferably at least one selected from the group consisting of modified monomers represented by formulas (3 a) to (3 d).
CH 2 ＝CH-Rf 1 (3a)
(wherein Rf 1 Is a perfluoroalkyl group having 1 to 10 carbon atoms. )
CF 2 ＝CF-O-Rf 2 (3b)
(wherein Rf 2 Is a perfluoroalkyl group having 1 to 2 carbon atoms. )
CF 2 ＝CF-O-(CF 2 ) n CF＝CF 2 (3c)
(wherein n is 1 or 2.)
[ chemical 4]
(wherein X is 3 And X 4 Is F, cl or methoxy, Y is of the formula Y1 or Y2. )
[ chemical 5]
-CF＝CF- (Y1)
(in the formula Y2, Z and Z' are F or fluoroalkyl groups having 1 to 3 carbon atoms.)
The content of the modifying monomer (3) is preferably in the range of 0.00001 to 1.0 mass% relative to PTFE. The lower limit is more preferably 0.0001 mass%, still more preferably 0.001 mass%, still more preferably 0.005 mass%, still more preferably 0.010 mass%, still more preferably 0.030 mass%, still more preferably 0.050 mass%, still more preferably 0.070 mass%, still more preferably 0.10 mass%, particularly preferably 0.15 mass%, and most preferably 0.20 mass%. The upper limit is preferably 0.90 mass%, more preferably 0.50 mass%, still more preferably 0.45 mass%, still more preferably 0.40 mass%, particularly preferably 0.35 mass%, and most preferably 0.30 mass%.
For reasons of low viscosity at high temperature and excellent mechanical stability at high temperature, the above-mentioned modified monomer preferably contains at least one selected from the group consisting of hexafluoropropylene, vinylidene fluoride, fluoro (alkyl vinyl ether), perfluoroallyl ether, (perfluoroalkyl) ethylene, and a modified monomer having a functional group capable of reacting in radical polymerization and a hydrophilic group.
The modified monomer preferably contains at least one selected from the group consisting of hexafluoropropylene, perfluoro (alkyl vinyl ether) and (perfluoroalkyl) ethylene, more preferably perfluoro (alkyl vinyl ether), and still more preferably perfluoro (propyl vinyl ether) (hereinafter also referred to as PPVE).
The total amount of hexafluoropropylene unit, perfluoro (alkyl vinyl ether) unit and (perfluoroalkyl) ethylene unit is preferably in the range of 0.00001 to 1.0 mass% relative to PTFE. The lower limit of the total amount is more preferably 0.0001 mass%, still more preferably 0.001 mass%, still more preferably 0.005 mass%, still more preferably 0.010 mass%, still more preferably 0.030 mass%, still more preferably 0.050 mass%, still more preferably 0.070 mass%, still more preferably 0.10 mass%, particularly preferably 0.15 mass%, and most preferably 0.20 mass%. The upper limit is preferably 0.90 mass%, more preferably 0.50 mass%, still more preferably 0.45 mass%, still more preferably 0.40 mass%, particularly preferably 0.35 mass%, and most preferably 0.30 mass%.
By setting the total amount of the units, particularly the amount of perfluoro (alkyl vinyl ether) units, within the above-described range, the appearance of the obtained coating film can be further improved.
The modified monomer is also preferably a modified monomer having a functional group and a hydrophilic group that can react in radical polymerization (hereinafter referred to as "modified monomer (4)"). By including the polymerized unit based on the modified monomer (4), PTFE particles having a small particle diameter can be obtained, and an aqueous dispersion having high dispersion stability can be obtained.
In the polymerization for producing PTFE, the amount of the modifying monomer (4) is preferably more than 0.1ppm, more preferably 5ppm or more, still more preferably 10ppm or more in the aqueous medium. If the amount of the modifying monomer (4) is too small, the particle size of the obtained PTFE may be increased. The modified monomer (4) may be in the above range, and for example, the upper limit may be 5000ppm. In the above production method, the modifying monomer (4) may be added to the system during the reaction in order to improve the stability of the aqueous dispersion during or after the reaction.
Since the modified monomer (4) has high water solubility, the unreacted modified monomer (4) is easily removed in the concentration step or the precipitation/washing step, similarly to the fluorine-containing compound described later, even if it remains in the aqueous dispersion.
The above-mentioned modifying monomer (4) is incorporated into the polymer during the polymerization, but the concentration of the modifying monomer (4) in the polymerization system itself is low and the amount of the modifying monomer incorporated into the polymer is small, so that there is no problem that the heat resistance of PTFE is lowered or coloration occurs after firing.
The modified monomer (4) has a functional group and a hydrophilic group which can react in radical polymerization.
Examples of the hydrophilic group in the modified monomer (4) include-NH 2 、-PO 3 M、-OPO 3 M、-SO 3 M、-OSO 3 M, -COOM (in the formulae, M is H, a metal atom, NR) 7 4 Imidazolium with or without substituents, pyridinium with or without substituents or phosphonium with or without substituents, R 7 H or an organic group may be the same or different. Any 2 may be bonded to each other to form a ring). As the above hydrophilic group, among them, preferred is-SO 3 M and-COOM. The metal atom is preferably an alkali metal, and examples of the alkali metal include Na and K.
Examples of the "functional group capable of reacting during radical polymerization" in the modified monomer (4) include groups having an unsaturated bond such as a vinyl group and an allyl group.
Since the modified monomer (4) has a functional group capable of reacting during radical polymerization, it is presumed that, when used in the polymerization, it reacts with a fluorine-containing monomer at the initial stage of the polymerization reaction to form particles having a hydrophilic group derived from the modified monomer (4) and having high stability. Therefore, it is considered that the number of emulsified particles increases when the polymerization is carried out in the presence of the above-mentioned modifying monomer (4).
In the polymerization, the number of the modifying monomers (4) may be 1 or 2 or more.
In the polymerization, as the modifying monomer (4), a compound having an unsaturated bond may be used.
The above-mentioned modifying monomer (4) is preferably represented by the general formula (4):
CX i X k ＝CX j R a -(CZ 1 Z 2 ) k -Y 3 (4)
(wherein X is i 、X j And X k Each independently F, cl, H or CF 3 ；Y 3 Is a hydrophilic group; r is R a Is a linking group; z is Z 1 And Z 2 Each independently is H, F or CF 3 K is 0 or 1).
Examples of the hydrophilic group include-NH 2 、-PO 3 M、-OPO 3 M、-SO 3 M、-OSO 3 M, -COOM (in the formulae, M is H, a metal atom, NR) 7 4 Imidazolium with or without substituents, pyridinium with or without substituents or phosphonium with or without substituents, R 7 H or an organic group may be the same or different. Any 2 may be bonded to each other to form a ring). As the above hydrophilic group, among them, preferred is-SO 3 M or-COOM. As R 7 Preferably H or C 1-10 More preferably H or C 1-4 Further preferably H or C 1-4 Is a hydrocarbon group.
The metal atom may be a 1-valent or 2-valent metal atom, and examples thereof include alkali metal (group 1), alkaline earth metal (group 2), and the like, and Na, K, and Li are preferable.
R is as described above a Is a linking group. The term "linking group" as used herein refers to a divalent linking group. The linking group may be a single bond, preferably contains at least 1 carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. The upper limit is not limited, and may be, for example, 100 or less, or 50 or less.
The linking group may be a chain or branched, cyclic or acyclic structure, saturated or unsaturated, substituted or unsubstituted, may contain 1 or more hetero atoms selected from the group consisting of sulfur, oxygen and nitrogen as desired, or may contain 1 or more functional groups selected from the group consisting of esters, amides, sulfonamides, carbonyl groups, carbonates, carbamates, ureas and carbamates as desired. The linking group may not contain a carbon atom and may be a catenary heteroatom such as oxygen, sulfur, or nitrogen.
R is as described above a For example, a catenary heteroatom such as oxygen, sulfur, nitrogen, or a 2-valent organic group is preferable.
R a In the case of a 2-valent organic group, the hydrogen atom bonded to the carbon atom may be substituted with a halogen other than fluorine, for example, chlorine, and may or may not contain a double bond. In addition, R a The compound may be either chain-shaped or branched, or cyclic or acyclic. In addition, R a Functional groups (e.g., esters, ethers, ketones, amines, halides, etc.) may be included.
In addition, R a May be a non-fluorine 2-valent organic group, or may be a partially fluorinated or perfluorinated 2-valent organic group.
As R a For example, the hydrocarbon group may be a hydrocarbon group to which a fluorine atom is not bonded to a carbon atom, a hydrocarbon group in which a part of hydrogen atoms bonded to a carbon atom is substituted with a fluorine atom, a hydrocarbon group in which all hydrogen atoms bonded to a carbon atom are substituted with a fluorine atom, - (c=o) -O-, or a hydrocarbon group containing- (c=o) -which may contain an oxygen atom, may contain a double bond, or may contain a functional group.
The modifying monomer (4) is preferably at least one selected from the group consisting of compounds represented by the following formulas (4 a) to (4 e).
CF 2 ＝CF-(CF 2 ) n1 -Y 3 (4a)
(wherein n1 represents an integer of 1 to 10, Y) 3 Representation of-SO 3 M 1 or-COOM 1 ，M 1 Representation H, NH 4 Or an alkali metal. )
CF 2 ＝CF-(CF 2 C(CF 3 )F) n2 -Y 3 (4b)
(wherein n2 represents an integer of 1 to 5, Y) 3 The same as defined above
CF 2 ＝CF-O-(CFX 1 ) n3 -Y 3 (4c)
(wherein X is 1 Represents F or CF 3 N3 represents an integer of 1 to 10, Y 3 The same definition as above. )
CF 2 ＝CF-O-(CF 2 CFX 1 O) n4 -CF 2 CF 2 -Y 3 (4d)
(in the formula (I),n4 represents an integer of 1 to 10, Y 3 And X 1 The same definition as above. )
CX 2 2 ＝CFCF 2 -O-(CF(CF 3 )CF 2 O) n5 -CF(CF 3 )-Y 3 (4e)
(wherein each X 2 And the same, represents F or H. n5 represents 0 or an integer of 1 to 10, Y 3 The same definition as above. )
Examples of the alkali metal include Na and K.
In the formula (4 a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. From the viewpoint of obtaining moderate water solubility and surface activity, Y is 3 preferably-COOM 1 M is not easily remained as an impurity, and the heat resistance of the obtained molded article can be improved 1 Preferably H or NH 4 。
Examples of the perfluorovinyl alkyl compound represented by the above formula (4 a) include CF 2 ＝CFCF 2 COOM 1 (wherein M 1 The same definition as above).
In the above formula (4 b), from the viewpoint of emulsifying ability, n2 is preferably an integer of 3 or less, and Y is preferably an integer of 3 or less from the viewpoint of obtaining proper water solubility and surface activity 3 preferably-COOM 1 M is not easily remained as an impurity, and the heat resistance of the obtained molded article can be improved 1 Preferably H or NH 4 。
In the formula (4 c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y is preferably an integer of 5 or less in terms of obtaining moderate water solubility and surface activity 3 preferably-COOM 1 From the aspect of good dispersion stability, M is 1 Preferably H or NH 4 。
In the above formula (4 d), X is as described above in terms of surface activity 1 preferably-CF 3 From the viewpoint of water solubility, n4 is preferably an integer of 5 or less, and from the viewpoint of obtaining moderate water solubility and surface activity, Y is preferably an integer of 5 or less 3 preferably-COOM 1 M is as described above 1 Preferably H or NH 4 。
Examples of the perfluorovinyl ether compound represented by the above formula (4 d) include CF 2 ＝CFOCF 2 CF(CF 3 )OCF 2 CF 2 COOM 1 (wherein M 1 Representation H, NH 4 Or an alkali metal).
In the formula (4 e), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, from the viewpoint of emulsifying ability. From the viewpoint of obtaining moderate water solubility and surface activity, Y is 3 preferably-COOM 1 The M is not easily remained as impurities, and the heat resistance of the obtained molded article can be improved 1 Preferably H or NH 4 。
Examples of the perfluorovinyl alkyl compound represented by the above formula (4 e) include CH 2 ＝CFCF 2 OCF(CF 3 )COOM 1 、CH 2 ＝CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOM 1 (wherein M 1 The same definition as above).
The PTFE preferably has a core-shell structure. This can further suppress clogging of the coating gun and white spots of the coating film, and can further improve stirring stability.
Examples of the fluoropolymer having a core-shell structure include modified PTFE in which a core of high-molecular-weight PTFE and a shell of lower-molecular-weight PTFE or modified PTFE are contained in particles. Examples of such modified PTFE include PTFE described in JP-A2005-527652.
As the core-shell structure, the following structure can be adopted.
And (3) core: TFE homopolymer shell: TFE homopolymers
And (3) core: modified PTFE shell: TFE homopolymers
And (3) core: modified PTFE shell: modified PTFE
And (3) core: TFE homopolymer shell: modified PTFE
The above structures may take the form of high and low molecular weight respectively. For example, the structure of the core of the high molecular weight TFE homopolymer and the shell of the low molecular weight TFE homopolymer, the structure of the core of the high molecular weight modified PTFE and the shell of the low molecular weight modified PTFE, the structure of the core of the high molecular weight TFE homopolymer and the shell of the low molecular weight modified PTFE, the structure of the core of the low molecular weight modified PTFE and the shell of the high molecular weight TFE homopolymer, the structure of the core of the low molecular weight modified PTFE and the shell of the high molecular weight modified PTFE, and the structure of the core of the low molecular weight TFE homopolymer and the shell of the high molecular weight modified PTFE can be adopted.
The PTFE is preferably a core-shell structure having a shell of low molecular weight PTFE, and particularly preferably a core-shell structure having a core of modified PTFE and a shell of low molecular weight PTFE. This can greatly improve the mechanical stability of the coating composition, further suppress clogging of the coating gun and white spots of the coating film, and further improve the stirring stability.
The shell can be made of low molecular weight PTFE by polymerizing a monomer composition comprising TFE in the presence of a chain transfer agent.
The monomer composition containing TFE may contain TFE alone or may contain TFE and a modifying monomer.
The modified monomer constituting the modified PTFE of the core is preferably at least one selected from the group consisting of PAVE, PFAE, and the above-mentioned cyclic monomer. As PAVE, PPVE, PEVE, PMVE and the like are mentioned, and PPVE is preferable.
PFAE may be, for example, (perfluorohexyl) ethylene, PFBE is preferable.
The cyclic monomer may be a vinyl hetero cyclic compound represented by the general formula (ii), and perfluoro-2, 2-dimethyl-1, 3-dioxole [ PDD ] is preferable.
In the modified PTFE constituting the core, the content of the polymerized unit based on the modified monomer is preferably in the range of 0.00001 to 1.0 mass% relative to PTFE. The lower limit is more preferably 0.0001 mass%, still more preferably 0.001 mass%, still more preferably 0.005 mass%, still more preferably 0.010 mass%, still more preferably 0.030 mass%, still more preferably 0.050 mass%, still more preferably 0.070 mass%, still more preferably 0.10 mass%, particularly preferably 0.15 mass%, and most preferably 0.20 mass%. The upper limit is preferably 0.90 mass%, more preferably 0.50 mass%, still more preferably 0.45 mass%, still more preferably 0.40 mass%, particularly preferably 0.35 mass%, and most preferably 0.30 mass%.
The low molecular weight PTFE in the above-described shell may be obtained by polymerizing a monomer composition comprising TFE in the presence of a chain transfer agent. The chain transfer agent is not particularly limited as long as it can reduce the molecular weight of PTFE constituting the shell, and examples thereof include non-peroxidized organic compounds such as water-soluble alcohols, hydrocarbons, fluorinated hydrocarbons, and the like; a water-soluble organic peroxide such as succinyl peroxide [ DSP ]; persulfates such as ammonium persulfate [ APS ], potassium persulfate [ KPS ], and the like. In the above-described shell-forming polymerization, as the chain transfer agent, at least one of the above-described non-peroxidized organic compound, water-soluble organic peroxide and persulfate is preferably used.
Among the above chain transfer agents, 1 or 2 or more types of non-peroxidized organic compounds, water-soluble organic peroxides and persulfates, respectively, may be used.
The chain transfer agent is preferably composed of at least one selected from the group consisting of water-soluble alcohols having 1 to 4 carbon atoms, hydrocarbons having 1 to 4 carbon atoms and fluorinated hydrocarbons having 1 to 4 carbon atoms, more preferably at least one selected from the group consisting of methane, ethane, n-butane, isobutane, methanol and isopropanol, and even more preferably at least one selected from the group consisting of methanol and isobutane, from the viewpoint of good dispersibility and uniformity in the reaction system.
The polymerization is generally carried out in an aqueous medium. The amount of the chain transfer agent is preferably 0.001 to 10000ppm relative to the aqueous medium. The amount of the chain transfer agent is more preferably 0.01ppm or more, still more preferably 0.05ppm or more, particularly preferably 0.1ppm or more, relative to the aqueous medium. Further, the content of the water-based medium is more preferably 1000ppm or less, still more preferably 750ppm or less, particularly preferably 500ppm or less.
In the PTFE having a core-shell structure, the upper limit of the proportion of the core is preferably 99.5 mass%, more preferably 99.0 mass%, further preferably 98.0 mass%, further more preferably 97.0 mass%, particularly preferably 95.0 mass%, and most preferably 90.0 mass%.
In the PTFE having a core-shell structure, the lower limit of the proportion of the shell is preferably 0.5 mass%, more preferably 1.0 mass%, further preferably 2.0 mass%, further more preferably 3.0 mass%, particularly preferably 5.0 mass%, and most preferably 10.0 mass%.
In the PTFE having a core-shell structure, the core or the shell may have a structure of 2 layers or more. For example, it may have the following 3-layer structure: has a core center portion of modified PTFE, a core outer layer portion of TFE homopolymer, and a shell of low molecular weight PTFE.
In the PTFE having a core-shell structure, the extrusion pressure at the compression ratio 1500 is preferably 80MPa or less, more preferably 70MPa or less, and still more preferably 60MPa or less. The extrusion pressure within the above range at the compression ratio 1500 can be achieved in the manufacturing method described later.
In the present specification, the above "extrusion pressure at compression ratio 1500" is measured according to the following procedure.
The PTFE aqueous dispersion was coagulated with methanol, the wet PTFE powder obtained was further subjected to soxhlet extraction with methanol, and the additive containing the nonionic surfactant was removed. The wet PTFE powder obtained after the removal was dried at 150℃for 18 hours to obtain PTFE powder.
Alternatively, after the aqueous PTFE dispersion after completion of polymerization, that is, before the addition of the nonionic surfactant, is diluted with deionized water so that the PTFE concentration is 10 to 15 mass%, mechanical shearing is applied to obtain a wet PTFE powder. The wet PTFE powder was dried at 150℃for 18 hours to obtain a PTFE powder.
To 100 parts by mass (60G) of the obtained PTFE powder, 20.5 parts by mass (12.3G) of a hydrocarbon oil (trade name: isopar G, manufactured by Exxon chemical Co., ltd.) was added, and the mixture was aged at room temperature (25.+ -. 1 ℃ C.) for 1 hour, and paste extrusion was performed using an extrusion die (compression ratio: 1500) having a cylinder with an inner diameter of 25.4 mm. The pressure at the portion where the pressure in the latter half of extrusion reached an equilibrium state was divided by the barrel cross-sectional area, and the obtained value was taken as the extrusion pressure at the compression ratio of 1500.
The average primary particle diameter of the PTFE is preferably 500nm or less, more preferably 400nm or less, and still more preferably 350nm or less. The lower limit of the average primary particle diameter is not particularly limited, and may be, for example, 100nm. In terms of molecular weight, for example, in the case of high molecular weight PTFE, it is preferably 150nm or more, more preferably 200nm or more.
The average primary particle diameter can be determined as follows: the average primary particle diameter is determined from the transmittance of 550nm projected light per unit length of the aqueous dispersion whose resin solid content concentration is adjusted to 0.15 mass%, and the calibration curve of the number of standard length average primary particle diameters determined by measuring the orientation diameters in the transmission electron micrograph.
In the above PTFE, the content of PTFE particles having an aspect ratio of 5 or more is preferably less than 1.5% by mass relative to the total content of PTFE particles.
The aspect ratio was determined by observing an aqueous PTFE dispersion diluted so that the solid content concentration was about 1 mass% with a Scanning Electron Microscope (SEM), and performing image processing on 200 or more randomly extracted particles, and averaging the ratio of the long diameter to the short diameter.
The Standard Specific Gravity (SSG) of the PTFE is preferably 2.220 or less, more preferably 2.190 or less. And is preferably 2.140 or more, more preferably 2.150 or more. The SSG was measured by the water displacement method according to ASTM D-792 using a sample molded according to ASTM D4895-89.
The PTFE generally has stretchability, fibrillation characteristics, and non-melt secondary processability.
The above-mentioned non-melt secondary processability means that the melt flow rate cannot be measured at a temperature higher than the crystallization melting point, i.e., the property of not easily flowing even in the melting temperature region, according to ASTM D-1238 and D-2116.
Examples of the melt-processible fluororesin include Tetrafluoroethylene (TFE)/perfluoro (alkyl vinyl ether) (PAVE) copolymer (PFA), TFE/perfluoroallyl ether (PFAE) copolymer, TFE/Hexafluoropropylene (HFP) copolymer (FEP), ethylene (Et)/TFE copolymer (ETFE), et/TFE/HFP copolymer, poly (chlorotrifluoroethylene) (PCTFE), chlorotrifluoroethylene (CTFE)/TFE copolymer, et/CTFE copolymer, and polyvinylidene difluoride (PVDF), and 1 or 2 or more kinds thereof can be used.
The term "melt processability" means that the polymer can be melted and processed by using conventional processing equipment such as an extruder and an injection molding machine. Therefore, the Melt Flow Rate (MFR) of the melt-processible fluororesin is usually 0.01 to 100g/10 min.
In the present specification, the above MFR is a value measured as follows: according to ASTM D1238, the mass (g/10 min) of the polymer flowing out of a nozzle having an inner diameter of 2mm and a length of 8mm every 10 minutes was measured under a load (e.g., 5kg in the case of PFA, FEP and ETFE) at a measurement temperature (e.g., 372℃in the case of PFA or FEP and 297℃in the case of ETFE) determined according to the type of the fluoropolymer using a melt flow index meter (manufactured by the Co., ltd., an Tian refiner) and the obtained value was used as MFR.
The melting point of the melt-processible fluororesin is preferably 100 to 333 ℃, more preferably 140 ℃ or higher, still more preferably 160 ℃ or higher, particularly preferably 180 ℃ or higher, still more preferably 332 ℃ or lower.
In the present specification, the melting point of the melt processible fluororesin is a temperature corresponding to a maximum value in a melting temperature curve when the temperature is raised at a rate of 10 ℃/min using a differential scanning calorimeter [ DSC ].
The melt-processible fluororesin is preferably at least one selected from the group consisting of PFA and FEP, and more preferably FEP.
The PFA is not particularly limited, and the molar ratio of TFE unit to PAVE unit (TFE unitmeta/PAVE unit) is 70/30 or more and less than 99/1. More preferably, the molar ratio is 70/30 or more and 98.9/1.1 or less, and still more preferably, the molar ratio is 80/20 or more and 98.9/1.1 or less. If the TFE unit is too small, the mechanical properties tend to be lowered, while if it is too large, the melting point is too high, and the moldability tends to be lowered. The PFA is also preferably a copolymer having 0.1 to 10 mol% of monomer units derived from a monomer copolymerizable with TFE and PAVE and 90 to 99.9 mol% of TFE units and PAVE units. Examples of monomers copolymerizable with TFE and PAVE include HFP and CZ 3 Z 4 ＝CZ 5 (CF 2 ) n Z 6 (wherein Z is 3 、Z 4 And Z 5 Identical or different, representing hydrogen or fluorine atoms, Z 6 Represents a hydrogen atom, a fluorine atom or a chlorine atom, n represents an integer of 2 to 10), and CF 2 ＝CF-OCH 2 -Rf 7 (wherein Rf 7 Alkyl perfluorovinyl ether derivatives represented by perfluoroalkyl groups having 1 to 5 carbon atoms).
The melting point of the PFA is preferably 180 to less than 322 ℃, more preferably 230 to 320 ℃, and even more preferably 280 to 320 ℃.
The Melt Flow Rate (MFR) of the PFA is preferably 1 to 100g/10 min.
The thermal decomposition initiation temperature of the PFA is preferably 380 ℃ or higher. The thermal decomposition initiation temperature is more preferably 400℃or higher, and still more preferably 410℃or higher.
In the present specification, the thermal decomposition initiation temperature is the following temperature: the thermal decomposition initiation temperature was obtained by heating 10mg of the sample from room temperature at a heating rate of 10℃per minute using a differential thermal-thermogravimetry apparatus [ TG-DTA ] (trade name: TG/DTA6200, manufactured by SEIKO electronics Co., ltd.) and decreasing the sample by 1% by mass.
The FEP is not particularly limited, but a copolymer having a molar ratio of TFE unit to HFP unit (TFE unit/HFP unit) of 70/30 or more and less than 99/1 is preferable. More preferably, the molar ratio is 70/30 or more and 98.9/1.1 or less, and still more preferably, the molar ratio is 80/20 or more and 98.9/1.1 or less. If the TFE unit is too small, the mechanical properties tend to be lowered, and if the TFE unit is too large, the melting point is too high, and the moldability tends to be lowered. The FEP is also preferably a copolymer having 0.1 to 10 mol% of monomer units derived from a monomer copolymerizable with TFE and HFP and 90 to 99.9 mol% of TFE units and HFP units. Examples of the monomer copolymerizable with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.
The melting point of the FEP is preferably 150 to less than 322 ℃, more preferably 200 to 320 ℃, and even more preferably 240 to 320 ℃.
The MFR of the FEP is preferably 1 to 100g/10 min.
The thermal decomposition initiation temperature of the FEP is preferably 360 ℃ or higher. The thermal decomposition initiation temperature is more preferably 380℃or higher, and still more preferably 390℃or higher.
The content of each monomer unit of the melt-processible fluororesin can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the kind of monomer.
The fluoroethylene-based polymer preferably contains PTFE, and may also contain PTFE and optionally a melt-processible fluororesin. The melt-processible fluororesin is preferably at least one selected from the group consisting of PFA and FEP.
PTFE tends to cause fibrillation and aggregation due to friction with a high-hardness filler, and tends to cause clogging of a coating gun and white spots of a coating film during coating, but in the coating composition of the present disclosure, clogging of a coating gun and white spots of a coating film are not likely to occur even when PTFE is contained.
When the fluoroethylene polymer contains PTFE, the content of PTFE is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more, relative to the fluoroethylene polymer.
The content of the fluoroethylene-based polymer is 1 to 50% by mass relative to the coating composition. The content is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, particularly preferably 20% by mass or more, and preferably 49% by mass or less, still more preferably 45% by mass or less, relative to the coating composition.
The coating composition of the present disclosure comprises at least one filler material selected from the group consisting of: (i) 0.1 to 80 mass% of a filler having a new mohs hardness of 9 or more relative to the fluoroethylene-based polymer; (ii) 0.1 to 120 mass% of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluoroethylene-based polymer; and (iii) 1 to 150 mass% of a filler having a new mohs hardness of less than 5 relative to the fluorine-containing ethylenic polymer.
In general, when the coating material contains such a filler, the abrasion resistance of the coating film is improved, while the fluorine-containing ethylenic polymer tends to aggregate due to friction, and the clogging of the coating gun and the white spots of the coating film tend to occur during coating. The coating composition of the present disclosure, despite containing the filler, is less likely to cause clogging of a coating gun or white spots of a coating film.
The coating composition of the present disclosure preferably comprises at least one selected from the group consisting of the above-described filler material (i) and the above-described filler material (ii).
The filler (i) has a new mohs hardness of 9 or more. The filler (i) preferably has a new mohs hardness of 10 or more, more preferably 11 or more, and still more preferably 12 or more.
Examples of the filler (i) include diamond, diamond fluoride, corundum, boron nitride, boron carbide, silicon carbide, chrysoberyl, topaz, garnet, fused zirconia, tantalum carbide, titanium carbide, alumina, tungsten carbide, zirconium carbide, and the like, and 1 or 2 or more kinds thereof can be used.
Among them, at least one selected from the group consisting of silicon carbide, diamond, and alumina is preferable, and silicon carbide is more preferable.
The new mohs hardness may be different even for the same kind (name) of filler due to the crystal structure and other differences. The filler (i) is exemplified by the filler having a new mohs hardness of 9 or more and the type of filler is the type described above.
In the case where the coating composition of the present disclosure contains the filler (i), the content thereof is 0.1 to 80% by mass relative to the fluorine-containing ethylenic polymer. The content is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and further preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, relative to the fluorine-containing ethylenic polymer.
The filler (ii) has a new mohs hardness of 5 or more and less than 9.
Examples of the filler (ii) include iron oxide, ultramarine, titanium oxide, emerald, germanium, quartzite, silica, quartz, andalusite, tourmaline, and the like, and 1 or 2 or more kinds may be used.
Among them, at least one selected from the group consisting of titanium oxide and iron oxide is preferable, and titanium oxide is more preferable.
The filler (ii) is exemplified by the filler having a new mohs hardness of 5 or more and less than 9 and the type of filler is the type described above.
In the case where the coating composition of the present disclosure contains the filler (ii), the content thereof is 0.1 to 120% by mass relative to the fluorine-containing ethylenic polymer. The content is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably 8% by mass or more, particularly preferably 10% by mass or more, and is preferably 100% by mass or less, more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably 50% by mass or less, relative to the fluorine-containing ethylenic polymer.
The filler material (iii) has a new mohs hardness of less than 5. The filler (iii) may have a new mohs hardness of 1 or more, preferably 2 or more, more preferably 3 or more.
Examples of the filler (iii) include clay, talc, mica, and barium sulfate, and 1 or 2 or more kinds thereof may be used.
Among them, at least one selected from the group consisting of barium sulfate and talc is preferable, and barium sulfate is more preferable.
The filler (iii) is exemplified by the filler having a new mohs hardness of less than 5 and the type of filler is the type described above.
In the case where the coating composition of the present disclosure contains the filler (iii), the content thereof is 1 to 150% by mass relative to the fluorine-containing ethylenic polymer. The content is preferably 2% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably 8% by mass or more, still more preferably 10% by mass or more, particularly preferably 12% by mass or more, most preferably 15% by mass or more, and further preferably 130% by mass or less, more preferably 110% by mass or less, still more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less, most preferably 50% by mass, relative to the fluorine-containing ethylenic polymer.
The coating composition of the present disclosure comprises water. The coating composition of the present disclosure may be a water-based coating composition. The coating composition of the present disclosure is preferably obtained by dispersing particles of the above-described fluoroethylene-based polymer and the above-described filler in water.
The coating composition of the present disclosure may contain water as well as organic solvents such as non-fluorinated organic solvents, e.g., alcohols, ethers, ketones, and the like, fluorinated organic solvents having a boiling point of 40 ℃ or less. In this case, the water is preferably 90% by mass or more, more preferably 95% by mass or more, relative to the total amount of water and the organic solvent.
The coating compositions of the present disclosure preferably further comprise a nonionic surfactant. This can further suppress clogging of the coating gun and white spots of the coating film, and can further improve stirring stability.
The nonionic surfactant is preferably a nonionic surfactant containing no fluorine. For example, the following general formula (i) can be mentioned:
R 3 -O-A 1 -H(i)
(wherein R is 3 Is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, A 1 A polyoxyalkylene chain).
R 3 The number of carbon atoms of (2) is preferably 8 to 16, more preferably 10 to 14.R is R 3 When the number of carbon atoms is in the above range, the coating composition has high affinity for the fluoroethylenic polymer, and excellent mechanical stability can be achieved. In addition, clogging of the coating gun and white spots of the coating film can be further suppressed, and stirring stability can be further improved.
R is as described above 3 Preferably of the general formula (i-1)
CHR 31 R 32 -(i-1)
(wherein R is 31 Represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms, R 32 Represents an alkyl group having 1 to 17 carbon atoms, R 31 And R is R 32 An alkyl group having 7 to 17 total carbon atoms). As R as above 31 More preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, still more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and still more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. In addition, as R 32 More preferably an alkyl group having 1 to 15 carbon atoms, still more preferably an alkyl group having 1 to 14 carbon atoms, and still more preferably an alkyl group having 1 to 13 carbon atoms.
R is as described above 3 Alkyl groups having 8 to 18 carbon atoms and having an average methyl number of 2.0 or more are preferable. R is as described above 3 The average number of methyl groups in (a) is more preferably 2.5 or more, still more preferably 3.0 or more, still more preferably 3.5 or more, and particularly preferably 4.0 or more. In addition, R 3 The average number of methyl groups of (a) is preferably 12 or less, more preferably 10 or less, and still more preferably 8 or less.
In addition, the R is a component that can further suppress clogging of the coating gun, white spots of the coating film, and further improve stirring stability 3 The average number of methyl groups per 1 molecule is preferably 4.0 or more, more preferably 4.3 or more, still more preferably 4.7 or more, and most preferably 5.0 or more.
The R is the above-mentioned one, from the viewpoint that clogging of a coating gun and white spots of a coating film can be further suppressed and stirring stability can be further improved 3 Trimethylnonyl is preferred, and 2,6, 8-trimethyl-4-nonyl is particularly preferred.
The average number of methyl groups in the present specification is obtained by Soxhlet extraction with methanol added to a sample, and then using 1 H-NMR was measured on the extract.
Examples of the commercial products of the nonionic surfactant include Genapol X080 (product name, manufactured by Clariant corporation), the Noigen TDS series (manufactured by first Industrial pharmaceutical Co., ltd.) exemplified by Noigen TDS-80 (trade name) and Noigen TDS-100 (trade name), the Leocollol TD series (manufactured by LION corporation) exemplified by Leocol TD-90 (trade name), the Lionol TD series (manufactured by LION corporation), the T-Det A series (manufactured by Harcros Chemicals corporation) exemplified by T-Det A138 (trade name), the Tergitol 15S series (manufactured by Dow corporation), the Dispanol TOC (trade name, manufactured by Japanese fat Co., ltd.).
The nonionic surfactant may be a mixture of 2 different nonionic surfactants, preferably A 1 A mixture of compounds represented by the formula (i) having different average numbers of ethylene oxide units. For example, A of the above general formula (i) may be mentioned 1 A polyoxyalkylene chain compound having an average oxyethylene unit number of 7.0 to 12.0 and an average oxypropylene unit number of 0.0 to 2.0, and A of the above general formula (i) 1 A mixture of compounds having a polyoxyalkylene chain having an average number of oxyethylene units of 10.0 to 12.0.
In addition, for example, A of the above general formula (i) may be used 1 A compound having an average oxyethylene unit number of 7.0 or more and less than 10.0 and A of the above general formula (i) 1 A mixture of compounds having a polyoxyalkylene chain having an average number of oxyethylene units of 10.0 to 12.0.
The nonionic surfactant is more preferably poly (ethylene oxide) 2,6, 8-trimethyl-4-nonylether having an average ethylene oxide unit number of 4.0 to 18.0, poly (ethylene oxide) 2,6, 8-trimethyl-4-nonylether having an average ethylene oxide unit number of 6.0 to 12.0, or a mixture thereof. Nonionic surfactants of this type are also commercially available as TERGITOL TMN-6, TERGITOL TMN-10, and TERGITOL TMN-100X (both trade names, manufactured by Dow chemical Co.).
A in the above formula (i) 1 The average number of alkylene oxide units in (a) is preferably 5.0 to 20.0, more preferably 7.0 to 15.0, still more preferably 8.0 to 12.0, particularly preferably 10.0 to 12.0.
Particularly preferably, the ethylene oxide unit is contained, and the average number of ethylene oxide units is preferably 7.0 or more, more preferably 8.0 or more, still more preferably 10.1 or more, still more preferably 10.2 or more, preferably 14.0 or less, more preferably 13.0 or less, still more preferably 12.0 or less, still more preferably 10.8 or less, still more preferably 10.7 or less, particularly preferably 10.6 or less, and most preferably 10.5 or less.
The average alkylene oxide unit number in the present specification is obtained by Soxhlet extraction with methanol added to a sample, and then using 1 H-NMR was measured on the extract.
A in the above formula (i) 1 May be formed of ethylene oxide units and propylene oxide units. For example, the polyoxyalkylene chain may be formed of an average oxyethylene unit number of 5.0 to 20.0 and an average oxypropylene unit number of 0.0 to 2.0. The number of ethylene oxide units may comprise any of the broad or narrow unimodal distributions typically provided, or the broader or bimodal distributions obtained by blending. When the average number of propylene oxide units is more than 0.0, the ethylene oxide units and the propylene oxide units in the polyoxyalkylene chain may be arranged in a block or may be arranged in a random manner.
From the viewpoints of viscosity and mechanical stability of the PTFE aqueous dispersion, a polyoxyalkylene chain composed of an average number of oxyethylene units of 7.0 to 12.0 and an average number of oxypropylene units of 0.0 to 2.0 is preferable. If A 1 The average number of propylene units is preferably 0.5 to 1.5, since the foam is excellent in low foaming property.
The HLB of the nonionic surfactant is preferably 13.00 or more, more preferably 13.20 or more, still more preferably 14.00 or more, still more preferably 14.05 or more, and particularly preferably 14.10 or more. The content is preferably 15.00 or less, more preferably 14.90 or less, and particularly preferably 14.80 or less. By setting the HLB to the above range, the viscosity at high temperature can be reduced while maintaining mechanical stability.
The above HLB is a calculation formula using Griffin [ hlb=e/5 (where E is the weight% of ethylene oxide in the molecule); hlb= (e+p)/5 (where E is a parameter defined above.p is the weight% of polyol in the molecule); hlb=20 (1-S/N)/5 (where S is a saponification value of an ester.n is a neutralization value of fatty acids constituting the ester) ].
When 2 or more nonionic surfactants are used, the HLB is calculated from the HLB of each nonionic surfactant and the mass ratio thereof. For example, when the nonionic surfactant having an HLB of 14.00 is 60 mass% and the nonionic surfactant having an HLB of 15.00 is 40 mass% relative to the total content of the nonionic surfactants, the hlb=14.00×0.6+15.00×0.4=14.40.
The coating composition of the present disclosure preferably contains 2 or more nonionic surfactants having different hydrophilicities, and preferably contains 3 to 5 nonionic surfactants. As an index showing the difference in hydrophilicity, for example, the above-mentioned HLB, the coating composition of the present disclosure preferably contains a nonionic surfactant having an HLB of 13.00 or more and less than 14.10 and a nonionic surfactant having an HLB of 14.10 or more and 15.00 or less. When nonionic surfactants having different HLB are added, foaming can be suppressed without adding an antifoaming agent.
In addition, for example, the coating composition of the present disclosure preferably contains a nonionic surfactant having an HLB of 13.00 or more and less than 13.50 and a nonionic surfactant having an HLB of 13.50 or more and 15.00 or less (preferably 14.50 or less, more preferably 14.00 or less).
The cloud point of a nonionic surfactant is a measure of the solubility of the surfactant in water. The surfactant used in the coating composition of the present disclosure has a cloud point of 30 to 90 ℃, preferably 35 to 85 ℃, more preferably 40 to 80 ℃, still more preferably 45 to 75 ℃.
In the coating composition of the present disclosure, 2 or more nonionic surfactants having different cloud points are preferably added, and 3 to 5 nonionic surfactants are also preferably added. For example, the coating composition of the present disclosure preferably contains a nonionic surfactant having a cloud point of 30 ℃ to 60 ℃ and a nonionic surfactant having a cloud point of more than 60 ℃ and 90 ℃ or less, more preferably contains a nonionic surfactant having a cloud point of 35 to 60 ℃ and a nonionic surfactant having a cloud point of 65 to 80 ℃. When a nonionic surfactant having a high cloud point is used, mechanical stability can be improved. In addition, when nonionic surfactants having different cloud points are added, foaming can be suppressed without adding an antifoaming agent.
In addition, for example, the coating composition of the present disclosure preferably contains a nonionic surfactant having a cloud point of 30 ℃ to 60 ℃ and a nonionic surfactant having a cloud point of more than 60 ℃ and 90 ℃ or less, more preferably contains a nonionic surfactant having a cloud point of 35 to 60 ℃ and a nonionic surfactant having a cloud point of 65 to 80 ℃.
The nonionic surfactant preferably has an HLB of 14.05 to 14.35 and an average alkylene oxide unit number of 10.2 to 10.9, for example.
As a more specific constitution, it is preferable that the nonionic surfactant is R of the formula (i) 3 Is 2,6, 8-trimethyl-4-nonyl, A 1 A polyoxyethylene chain compound (component 1) having an average oxyethylene unit number of 7.0 to 9.0 and R of the formula (i) 3 Is 2,6, 8-trimethyl-4-nonyl, A 1 A mixture of compounds (component 2) having a polyethylene oxide chain and having an average number of ethylene oxide units of 10.0 to 12.0, wherein component 1 comprises 5 to 25 mass% and component 2 comprises 75 to 95 mass%. In the nonionic surfactant, the 1 st component is more preferably 10% by mass or more, still more preferably 15% by mass or less, and the 2 nd component is more preferably 85% by mass or more, still more preferably 90% by mass or less.
The nonionic surfactant preferably has an HLB of 13.00 to 13.50 and an average alkylene oxide unit number of 7.0 to 12.0.
As a more specific constitution, it is preferable that the nonionic surfactant is A of the formula (i) 1 A compound having a polyoxyethylene chain having an average oxyethylene unit number of 7.0 to 9.5 (component 1) and A of the formula (i) 1 A mixture of compounds (component 2) having a polyethylene oxide chain and having an average number of ethylene oxide units of 10.0 to 12.0, wherein component 1 comprises 40 to 70 mass% and component 2 comprises 30 to 60 mass%. In the nonionic surfactant, the 1 st component is more preferably 45% by mass or more, still more preferably 65% by mass or less, and the 2 nd component is more preferably 35% by mass or more, still more preferably 55% by mass or less.
The content of the nonionic surfactant is preferably 4% by mass or more, more preferably 4.5% by mass or more, still more preferably 5% by mass or more, still more preferably 5.5% by mass or more, and is preferably 12% by mass or less, more preferably 10% by mass or less, still more preferably 8% by mass or less, and particularly preferably 7% by mass or less, relative to the fluoroethylene-based polymer.
If the amount of the nonionic surfactant is too large, the viscosity may become higher; if the amount is too small, the storage stability and mechanical stability may be lowered.
In the coating composition of the present disclosure, the content of the fluorosurfactant relative to the above coating composition is preferably 1000 ppb by mass or less.
The coating composition of the present disclosure, although substantially free of fluorosurfactant, can further suppress clogging of a coating gun, white spots of a coating film, and can further improve stirring stability. In addition, the viscosity at high temperature can be reduced, and the mechanical stability at high temperature can be made excellent.
The content of the fluorosurfactant is preferably 700 ppb by mass or less, more preferably 600 ppb by mass or less, further preferably 500 ppb by mass or less.
The content of the fluorosurfactant may be at least the lower limit of detection, at least the lower limit of quantification, or at least 100 ppb by mass.
In the coating composition of the present disclosure, the content of the fluorosurfactant is a value measured by liquid chromatography mass spectrometry as described in examples described later. Specifically, the measurement can be performed by the following method.
[ method for measuring the content of fluorosurfactant ]
The solid content of the aqueous dispersion was measured, and an amount of the aqueous dispersion corresponding to 1.5g of the PTFE solid content was weighed in a 100mL screw tube. Thereafter, water and methanol were added so that the extraction solvent was 37g of water/methanol=10/90 mass% to be combined with the water contained in the aqueous dispersion, and shaking was sufficient until precipitation. The liquid phase was extracted, and centrifuged at 4000rpm for 1 hour to extract the supernatant. Instead of such methanol extraction, a method of adding methanol to an aqueous dispersion and performing soxhlet extraction may be used.
The fluorosurfactant in the extract obtained as described above is measured by a liquid chromatograph mass spectrometer.
In the case where the above-mentioned fluoroethylene polymer is a polymer obtained by polymerization using a fluorosurfactant, a nonionic surfactant may be added to an aqueous dispersion of the above-mentioned fluoroethylene polymer in which polymerization is completed, and the amount of the fluorosurfactant may be adjusted to the above-mentioned range by concentration or the like.
Examples of the fluorosurfactant include a fluorine-containing anionic surfactant.
The fluorinated anionic surfactant may be represented by the following general formula (N) 0 ) In addition to anionic groups Y 0 A surfactant containing fluorine atoms, the total carbon number of the other parts of the surfactant being 20 or less.
The fluorine-containing surfactant may be a surfactant having an anionic portion with a molecular weight of 1000 or less.
The "anionic portion" refers to a portion of the fluorosurfactant other than a cation. For example, inF (CF) represented by formula (I) described below 2 ) n1 In the case of COOM, it is "F (CF) 2 ) n1 COO'.
The fluorosurfactant may also be a fluorosurfactant having a log pow of 3.5 or less, preferably 3.4 or less. The LogPOW is a partition coefficient between 1-octanol and water, and is represented by LogP [ in the formula, P represents a ratio of concentration of fluorosurfactant in octanol to concentration of fluorosurfactant in water when phase separation of octanol/water (1:1) mixed solution containing fluorosurfactant occurs ].
The LogPOW is calculated as follows: in the column: TOSOH ODS-120T columnManufactured by eastern co.) eluent: acetonitrile/0.6 mass% HClO4 water = 1/1 (vol/vol%), flow rate: 1.0 ml/min, sample size: 300 μl, column temperature: 40 ℃, detection light: HPLC was performed on standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) having known octanol/water distribution coefficients under UV210nm conditions to prepare calibration curves for each elution time and known octanol/water distribution coefficients, and the above-mentioned LogPOW was calculated from the elution time of HPLC in the sample solution based on the calibration curves.
The fluorinated surfactant is specifically a fluorinated surfactant described in U.S. patent application publication No. 2007/0015864, U.S. patent application publication No. 2007/0015865, U.S. patent application publication No. 2007/0016377, U.S. patent application publication No. 2007/0276103, U.S. patent application publication No. 2007/0117944, U.S. patent application publication No. 2007/142541, U.S. patent application publication No. 2008/0015319, U.S. patent No. 3250808, U.S. patent No. 3271341, japanese patent application laid-open No. 2003-119204, international publication No. 2005/042593, international publication No. 2008/060461, international publication No. 2007/046377, international publication No. 2007/119526, international publication No. 2007/046482, international publication No. 2007/046345, U.S. 2014/8531, international publication No. 2013/189824, and International publication No. 2013/1802226, and the like.
The fluorinated anionic surfactant may be represented by the following general formula (N) 0 )：
X n0 -Rf n0 -Y 0 (N 0 )
(wherein X is n0 H, cl or sum F. Rf (radio frequency identification) n0 An alkylene group having 3 to 20 carbon atoms, which is chain, branched or cyclic and in which part or all of H is substituted with F, and which may contain 1 or more ether linkages and in which part of H may be substituted with Cl. Y is Y 0 Is an anionic group).
Y 0 The anionic groups of (C) may be-COOM, -SO 2 M or-SO 3 M may be-COOM, or-SO 3 M。
M is H, a metal atom, NR 7 4 Imidazolium with or without substituents, pyridinium with or without substituents or phosphonium with or without substituents, R 7 Is H or an organic group.
Examples of the metal atom include alkali metal (group 1) and alkaline earth metal (group 2), and are Na, K, and Li.
As R 7 Can be H or C 1-10 The organic group of (C) may be H or C 1-4 The organic radical of (2) may also be H or C 1-4 Is a hydrocarbon group.
M may be H, a metal atom or NR 7 4 Can be H, alkali metal (group 1), alkaline earth metal (group 2) or NR 7 4 H, na, K, li or NH 4 。
The Rf described above n0 More than 50% of H may be substituted by fluorine.
As the above general formula (N) 0 ) The compounds represented may be:
the following general formula (N) 1 ) The compound represented:
X n0 -Rf m -Y 0 (N 1 )
(wherein X is n0 Is H,Cl and F, rf m Is a linear or branched perfluoroalkylene radical having 3 to 15 carbon atoms, Y 0 As defined above. ) (more specifically, the following general formula (N) 1a ) The compound represented:
X n0 -(CF 2 ) m1 -Y 0 (N 1a )
(wherein X is n0 H, cl and F, m1 is an integer of 3 to 15, Y 0 As defined above. ) A) is provided;
the following general formula (N) 2 ) The compound represented:
Rf n1 -O-(CF(CF 3 )CF 2 O) m2 CFX n1 -Y 0 (N 2 )
(wherein Rf n1 Is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, X n1 Is F or CF 3 ，Y 0 As defined above. ) The method comprises the steps of carrying out a first treatment on the surface of the
The following general formula (N) 3 ) The compound represented:
Rf n2 (CH 2 ) m3 -(Rf n3 ) q -Y 0 (N 3 )
(wherein Rf n2 Is a partially fluorinated or fully fluorinated alkyl group having 1 to 13 carbon atoms and optionally containing an ether bond, m3 is an integer of 1 to 3, rf n3 Is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, Y 0 As defined above. ) The method comprises the steps of carrying out a first treatment on the surface of the
The following general formula (N) 4 ) The compound represented:
Rf m4 -O-L 4 -Y 0 (N 4 )
(wherein Rf m4 Is a linear or branched partially fluorinated or fully fluorinated aliphatic group which may contain an ether bond and/or chlorine, L4 represents a partially fluorinated or fully fluorinated linear alkylene or aliphatic hydrocarbon group, Y 0 As defined above. ) (more specifically, the following general formula (N) 4a ) The compound represented:
Rf n4 -O-(CY n1 Y n2 ) p CF 2 -Y 0 (N 4a )
(wherein Rf n4 Is a linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 12 carbon atoms and optionally containing an ether bond and/or chlorine, Y n1 And Y n2 Identical or different, H or F, p being 0 or 1, Y 0 As defined above. ) A) is provided; and
the following general formula (N) 5 ) The compound represented:
[ chemical 6]
(wherein X is n2 、X n3 And X n4 The alkyl group may be the same or different, and is H, F or a linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 6 carbon atoms and optionally containing an ether bond. Rf (radio frequency identification) n5 Is a linear or branched partially fluorinated or fully fluorinated alkylene group having 1 to 3 carbon atoms and optionally containing an ether bond, L is a linking group, Y 0 As defined above. Wherein X is n2 、X n3 、X n4 And Rf n5 The total number of carbon atoms is 18 or less).
As the above general formula (N) 0 ) More specifically, examples of the compound represented by the formula (I) include a perfluorocarboxylic acid (I) represented by the following general formula (I), an omega-H perfluorocarboxylic acid (II) represented by the following general formula (II), a perfluoropolyether carboxylic acid (III) represented by the following general formula (III), a perfluoroalkylalkylene carboxylic acid (IV) represented by the following general formula (IV), a perfluoroalkoxy fluorocarboxylic acid (V) represented by the following general formula (V), a perfluoroalkylsulfonic acid (VI) represented by the following general formula (VI), an omega-H perfluorosulfonic acid (VII) represented by the following general formula (VII), a perfluoroalkylalkylene sulfonic acid (VIII) represented by the following general formula (VIII), an alkylalkylene carboxylic acid (IX) represented by the following general formula (IX), a fluorocarboxylic acid (X) represented by the following general formula (X), an alkoxyfluorosulfonic acid (XI) represented by the following general formula (XI), and a compound (XII) represented by the following general formula (XII).
The perfluorocarboxylic acid (I) is represented by the following general formula (I)
F(CF 2 ) n1 COOM (I)
(wherein n1 is an integer of 3 to 14, M is H, a metal atom, NR 7 4 Imidazolium with or without substituents, pyridinium with or without substituents or phosphonium with or without substituents, R 7 Is H or an organic group).
The omega-H perfluorocarboxylic acid (II) is represented by the following general formula (II)
H(CF 2 ) n2 COOM (II)
(wherein n2 is an integer of 4 to 15, and M is as defined above).
The perfluoropolyether carboxylic acid (III) is represented by the following general formula (III)
Rf 1 -O-(CF(CF 3 )CF 2 O) n3 CF(CF 3 )COOM (III)
(wherein Rf 1 A perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above).
The perfluoropolyether carboxylic acid (III) is preferably one having 7 or less total carbon atoms and LogPOW3.5 or less. The total number of carbon atoms is particularly preferably 5 to 7. The LogPOW is more preferably 3.4 or less.
The perfluoroalkyl alkylene carboxylic acid (IV) is represented by the following general formula (IV)
Rf 2 (CH 2 ) n4 Rf 3 COOM (IV)
(wherein Rf 2 Is a perfluoroalkyl group having 1 to 5 carbon atoms, rf 3 Linear or branched perfluoroalkylene groups having 1 to 3 carbon atoms, n4 is an integer of 1 to 3, and M is defined as above).
The above-mentioned alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V)
Rf 4 -O-CY 1 Y 2 CF 2 -COOM (V)
(wherein Rf 4 Is a linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 12 carbon atoms and optionally containing an ether bond and/or chlorine, Y 1 And Y 2 Identical or different, H or F, M being as defined above) are providedShown.
The perfluoroalkyl sulfonic acid (VI) is represented by the following general formula (VI)
F(CF 2 ) n5 SO 3 M (VI)
(wherein n5 is an integer of 3 to 14, and M is as defined above).
The omega-H perfluorosulfonic acid (VII) is represented by the following general formula (VII)
H(CF 2 ) n6 SO 3 M (VII)
(wherein n6 is an integer of 4 to 14, and M is as defined above).
The perfluoroalkyl alkylene sulfonic acid (VIII) is represented by the following general formula (VIII)
Rf 5 (CH 2 ) n7 SO 3 M (VIII)
(wherein Rf 5 A perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is defined as above).
The above-mentioned alkyl alkylene carboxylic acid (IX) is represented by the following general formula (IX)
Rf 6 (CH 2 ) n8 COOM (IX)
(wherein Rf 6 A linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, n8 is an integer of 1 to 3, and M is defined as above).
The fluorocarboxylic acid (X) is represented by the following general formula (X)
Rf 7 -O-Rf 8 -O-CF 2 -COOM (X)
(wherein Rf 7 A linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 6 carbon atoms and optionally containing an ether bond and/or chlorine, rf 8 A linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 6 carbon atoms, M being defined as above).
The above alkoxy fluorosulfonic acid (XI) is represented by the following general formula (XI)
Rf 9 -O-CY 1 Y 2 CF 2 -SO 3 M (XI)
(wherein Rf 9 Is of 1-12 carbon atomsA partially fluorinated or fully fluorinated alkyl group which may contain an ether bond, linear or branched and may contain chlorine, Y 1 And Y 2 The same or different, H or F, M being as defined above).
The above compound (XII) is represented by the following general formula (XII):
[ chemical 7]
(wherein X is 1 、X 2 And X 3 H, F and a linear or branched partially fluorinated or fully fluorinated alkyl group having 1 to 6 carbon atoms which may contain an ether bond, rf 10 Is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, Y 0 An anionic group).
Y 0 Can be-COOM, -SO 2 M or-SO 3 M may also be-SO 3 M or COOM (wherein M is as defined above).
Examples of L include a single bond and a partially fluorinated or fully fluorinated alkylene group having 1 to 10 carbon atoms which may contain an ether bond.
As described above, examples of the fluorine-containing anionic surfactant include carboxylic acid surfactants and sulfonic acid surfactants.
In the above-mentioned fluorine-containing anionic surfactant, the general formula (N) 1 ) In the case of the compound represented by the formula (N) 1 ) Rf in (f) m The number of carbon atoms of (3) to (6). In addition, the formula (N) is preferred 1a ) M1 in (2) is an integer of 3 to 6. In the case of using the perfluorocarboxylic acid (I), n1 in the general formula (I) is preferably an integer of 3 to 6.
The fluorinated anionic surfactant is particularly preferably a compound selected from the group consisting of fluorinated carboxylic acids having 4 to 9 carbon atoms, preferably 4 to 7 carbon atoms, which may have ether oxygen and/or chlorine, and salts thereof. The number of carbon atoms herein refers to the total number of carbon atoms in a molecule. The above-mentioned fluorinated anionic surfactants may be used in combination of two or more.
The fluorinated anionic surfactant is preferably a compound selected from the group consisting of fluorinated carboxylic acids having 4 to 9 carbon atoms, preferably 4 to 7 carbon atoms, having etheric oxygen and/or chlorine, and salts thereof. The fluorine-containing carboxylic acid having an etheric oxygen is a compound having 4 to 9 carbon atoms, preferably 4 to 7 carbon atoms, an etheric oxygen in the middle of the carbon chain of the main chain and a terminal-COOH. The terminal-COOH may form a salt.
The number of etheric oxygen atoms present in the middle of the main chain is 1 or more, preferably 1 to 4, more preferably 1 or 2.
The number of carbon atoms is preferably 5 to 7.
The fluorinated anionic surfactant is particularly preferably a carboxylic acid having 6 to 7 carbon atoms in the main chain, 1 to 4 etheric oxygen in the main chain, and a linear, branched or cyclic, partially fluorinated or fully fluorinated main chain, or a salt thereof. The "main chain" herein means a continuous chain having the largest number of carbon atoms.
The fluorosurfactant is specifically exemplified by F (CF) 2 ) 7 COOM、F(CF 2 ) 5 COOM、H(CF 2 ) 6 COOM、H(CF 2 ) 7 COOM、CF 3 O(CF 2 ) 3 OCHFCF 2 COOM、C 3 F 7 OCF(CF 3 )CF 2 OCF(CF 3 )COOM、CF 3 CF 2 CF 2 OCF(CF 3 )COOM、CF 3 CF 2 OCF 2 CF 2 OCF 2 COOM、C 2 F 5 OCF(CF 3 )CF 2 OCF(CF 3 )COOM、CF 3 OCF(CF 3 )CF 2 OCF(CF 3 )COOM、CF 2 ClCF 2 CF 2 OCF(CF 3 )CF 2 OCF 2 COOM、CF 2 ClCF 2 CF 2 OCF 2 CF(CF 3 )OCF 2 COOM、CF 2 ClCF(CF 3 )OCF(CF 3 )CF 2 OCF 2 COOM、CF 2 ClCF(CF 3 )OCF 2 CF(CF 3 )OCF 2 COOM、
The following formula:
[ chemical 8]
And the like (wherein M is as defined above). The anionic fluorosurfactant may be a mixture of two or more kinds, not a single composition.
In the coating composition of the present disclosure, an anionic surfactant is preferably contained for the purpose of adjusting viscosity or improving miscibility of pigments, fillers, and the like. The anionic surfactant may be added appropriately in a range where there is no problem in terms of economy and environment.
Examples of the anionic surfactant include a non-fluorinated anionic surfactant containing no fluorine, and a fluorinated anionic surfactant, preferably a non-fluorinated anionic surfactant containing no fluorine (i.e., a hydrocarbon-based anionic surfactant).
In the case of adjusting the viscosity, the type of the anionic surfactant is not particularly limited as long as it is a known anionic surfactant, and for example, non-fluorinated anionic surfactants described in International publication Nos. 2013/146950 and 2013/146947 may be used. Examples thereof include those having a saturated or unsaturated aliphatic chain having 6 to 40 carbon atoms, preferably 8 to 20 carbon atoms, more preferably 9 to 13 carbon atoms. The saturated or unsaturated aliphatic chain may be either a straight chain or a branched chain, or may have a cyclic structure. The hydrocarbon may be aromatic or may have an aromatic group. The hydrocarbon may have hetero atoms such as oxygen, nitrogen, sulfur, and the like.
Examples of the non-fluorinated anionic surfactant include alkyl sulfonate, alkyl sulfate, alkylaryl sulfate, and salts thereof; fatty acids (aliphatic carboxylic acids) and salts thereof; alkyl phosphate, alkylaryl phosphate or salts thereof; and the like, with alkyl sulfonates, alkyl sulfates, aliphatic carboxylic acids or salts thereof being preferred.
As the alkyl sulfate or a salt thereof, ammonium lauryl sulfate, sodium lauryl sulfate, or the like is preferable.
As the fatty acid (aliphatic carboxylic acid) or a salt thereof, succinic acid, capric acid, undecanoic acid, undecylenic acid, lauric acid, hydrododecanoic acid or a salt thereof is preferable.
The non-fluorinated anionic surfactant is preferably at least one selected from the group consisting of alkyl sulfate and salts thereof, and fatty acid and salts thereof.
The content of the non-fluorinated anionic surfactant varies depending on the type of the non-fluorinated anionic surfactant and other compounding agents, and is preferably 10ppm to 5000ppm based on the mass of the solid content of the fluorinated ethylenic polymer.
The lower limit of the amount of the non-fluorinated anionic surfactant to be added is more preferably 50ppm or more, still more preferably 100ppm or more. If the amount is too small, the viscosity adjusting effect is insufficient.
The upper limit of the amount of the non-fluorinated anionic surfactant is preferably 4000ppm or less, more preferably 3000ppm or less. If the amount is too large, the viscosity may increase, and particularly the viscosity at high temperature may increase. In addition, foaming may increase.
In order to adjust the viscosity of the coating composition of the present disclosure, in addition to the non-fluorine-containing anionic surfactant, for example, methylcellulose, alumina sol, polyvinyl alcohol, carboxylated vinyl polymer, acrylic polymer, and the like may be compounded.
In order to adjust the pH of the coating composition, a pH adjuster such as ammonia may be blended.
The pH of the coating composition of the present disclosure is preferably 8 to 13. More preferably 9 to 12, still more preferably 9 to 11.
The pH is measured at 25℃in accordance with JIS K6893.
The coating composition of the present disclosure may contain other water-soluble polymer compounds as needed within a range that does not impair the characteristics of the coating composition.
The other water-soluble polymer compound is not particularly limited, and examples thereof include polyethylene oxide (dispersion stabilizer), polyethylene glycol (dispersion stabilizer), polyvinylpyrrolidone (dispersion stabilizer), phenol resin, urea resin, epoxy resin, melamine resin, polyester resin, polyether resin, acrylic silicone resin, silicone polyester resin, and urethane resin. In addition, preservatives such as isothiazolone, azole, brobol, chlorothalonil, methylsulfonyl tetrachloropyridine, carbendazim, 2- [ (dichlorofluoromethyl) -thio ] -1H-isoindole-1, 3- (2H) -dione (Fluor Folpet), sodium diacetate, diiodomethyl-p-tolylsulfone and the like may be contained.
The coating compositions of the present disclosure may include an antifoaming agent. The defoaming agent can be added appropriately in a range where there is no problem in terms of economy and environment.
As the defoaming agent, various aqueous defoaming agents can be used, and examples thereof include: lower alcohols such as methanol, ethanol, butanol, etc.; higher alcohols such as amyl alcohol, polypropylene glycol and derivatives thereof; oils and fats such as oleic acid, tall oil, mineral oil, soap, and the like; surfactants such as sorbitan fatty acid esters, polyethylene glycol fatty acid esters, pluronic (registered trademark) nonionic surfactants, and the like; silicone surfactants such as siloxane and silicone resin may be used alone or in combination. Representative commercial products of the antifoaming agent include B-series (manufactured by Asahi Denka Co., ltd.) such as Adekanate B and Adekanate B1068; SN Defoamer series such as Foamaster DL, nopcon xz, SN Defoamer 113, 325, 308, 368, etc.; dehydran 1293, dehydran 1513[ san NOPCO Co., ltd. ]; flown SB-110N, SB-210, 510, 551, aqualen 800, 805, aqualen 1488[ manufactured by Kyowa Kagaku Co., ltd.; surfynol 104E, 440 (acetylene-based defoamer manufactured by Air Products); KS-607A (made by Xinyue chemical Co., ltd.); FS anti-foam (manufactured by Dow Corning Co.); BYK-020, 031, 073, W (manufactured by BigChemi); dehydran 981 (manufactured by Henkel Hakusui corporation); epan-410, 710, 720[ manufactured by first Industrial pharmaceutical Co., ltd. ]; tego Foamex series (manufactured by Tego Goldschmidt Co.); foamlex-747, TY-10, EP series (manufactured by Nikka chemical Co., ltd.), and the like. The content of the defoaming agent is preferably 0.01 to 10% by mass, particularly preferably 0.05 to 5% by mass, relative to the coating composition.
The coating compositions of the present disclosure may include an antifoaming agent, but preferably do not include an antifoaming agent. Without the inclusion of an antifoaming agent, it is advantageous from the viewpoint of cost. In addition, when an antifoaming agent is contained, coloring may occur when the coating composition is formed into a coating film.
The coating compositions of the present disclosure may comprise other additives, for example, comprise a coating raw material. Examples of the coating raw materials include pigments (extender pigments, flake pigments, etc.), pigment dispersants, thickeners, leveling agents, film forming aids, solid lubricants, anti-settling agents, moisture absorbers, surface regulators, thixotropic agents, viscosity modifiers, anti-gelling agents, ultraviolet absorbers, HALS (light stabilizers), gloss control agents, plasticizers, anti-blooming agents, anti-skinning agents, anti-scratch agents, rust inhibitors, mold inhibitors, antibacterial agents, antioxidants, flame retardants, anti-dripping agents, antistatic agents, silane coupling agents, carbon black, various reinforcing materials, various extenders, conductive fillers, metal powders such as colloidal silica, gold, silver, copper, platinum, stainless steel, and the like.
More preferably, the coating compositions of the present disclosure do not comprise colloidal silica.
The coating compositions of the present disclosure also preferably comprise a preservative. Examples of the preservative include hydrogen peroxide, organic bromine compounds, organic nitrogen sulfur compounds, organic iodine compounds, organic sulfur compounds, and triazine compounds, and from the viewpoint of corrosion resistance, organic iodine compounds and organic nitrogen sulfur compounds are preferable. Specific examples of the organoiodine compound and the organonitrogen sulfur compound include the Deltop series manufactured by OSAKA GAS CHEMICALS.
The amount of the preservative to be added is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, relative to the coating composition.
The gelation time of the coating composition of the present disclosure in the stirring stability test is preferably 4 hours or more, more preferably 6 hours or more, and still more preferably 8 hours or more. The upper limit is not particularly limited, and may be, for example, 24 hours.
The gelation time is a value measured by the following method.
A container containing 250ml of 200ml of the coating composition was immersed in a water tank at 40 ℃ and a stirring blade (spiral 4 blades) was rotated at 300rpm, and the time until aggregates were generated or solidified in the coating composition was measured and used as a gelation time.
The number of applications of the coating composition of the present disclosure in the continuous spray coatability test until the occurrence of spray gun clogging may be 70 times or more, preferably 100 times or more, more preferably 120 times or more, still more preferably 150 times or more. The upper limit is not particularly limited, and may be 200 times, for example.
The number of coating times until clogging of the spray gun occurred was a value measured by the following method.
In rock Tian Penqiang W88 (nozzle diameter 1.5 mm), a coating amount valve (paint amount) was reversed by 1 turn at 9.8N (5 kgf), and coating was performed intermittently with a trigger switch set so as to fully close the valve, and the number of times that paint was not sprayed from a spray gun was counted.
In the coating composition of the present disclosure, the number of coating times until occurrence of white spots in the continuous spray coatability test may be 45 or more, preferably 100 or more, more preferably 120 or more, still more preferably 140 or more, particularly preferably 150 or more, and most preferably 200 or more. The upper limit is not particularly limited, and may be 250 times, for example.
The number of painting times until the occurrence of white spots was measured by the following method.
In rock Tian Penqiang W88 (nozzle diameter: 1.5 mm), the discharge valve was reversed 1 turn at 9.8N (5 kgf), and under the setting of the full-closed valve, the trigger switch was intermittently applied to 10 sheets of 20 cm. Times.60 cm black kraft paper, and the number of times of white spot ejection was counted visually.
The coating composition of the present disclosure can be suitably used as a top coating (top coat) or a base coating (primer).
A coating composition suitable for a top coating (also referred to as a 1 st coating composition) and a coating composition suitable for a primer coating (also referred to as a 2 nd coating composition) among the coating compositions of the present disclosure are described below. The composition of the present disclosure may be the same as that of the coating composition described above, except for the following configuration.
In the 1 st coating composition, the filler is preferably at least one selected from the group consisting of: (i-1) 0.1 to 15 mass% of a filler having a new mohs hardness of 9 or more relative to the fluorine-containing ethylenic polymer; and (ii-1) 0.1 to 20 mass% of a filler having a new Mohs hardness of 5 or more and less than 9 relative to the fluorine-containing ethylenic polymer.
By including the filler having a high new mohs hardness in this manner, a coating film having more excellent abrasion resistance can be provided. In addition, the 1 st coating composition, although containing a filler having a high new mohs hardness, is not likely to cause clogging of a coating gun and white spots of a coating film at the time of coating.
The filler (i-1) may be the same as the filler (i).
When the 1 st coating composition contains the filler (i-1), the content thereof is 0.1 to 15 mass%, preferably 1 mass% or more, more preferably 3 mass% or more, still more preferably 5 mass% or more, and preferably 12 mass% or less, more preferably 10 mass% or less, relative to the fluorine-containing ethylenic polymer.
The filler (ii-1) may be the same as the filler (ii).
When the filler (ii-1) is contained in the coating composition 1, the content thereof is 0.1 to 20% by mass, preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably 8% by mass or more, particularly preferably 10% by mass or more, and preferably 18% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less, relative to the fluorine-containing ethylenic polymer.
The 1 st coating composition preferably does not contain a heat-resistant resin (excluding the above-mentioned fluoroethylene-based polymer). Examples of the heat-resistant resin include heat-resistant resins that can be used in the coating composition of item 2 described below.
In the 1 st coating composition, the content of the fluorine-containing ethylenic polymer is 1 to 50% by mass, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, particularly preferably 20% by mass or more, and preferably 49% by mass or less, more preferably 45% by mass or less, relative to the coating composition.
In the coating composition 1, the viscosity at 25℃is preferably 10 mPas to 1000 mPas in view of excellent sprayability in spray coating. The viscosity is more preferably 100 mPas or more, still more preferably 150 mPas or more, and still more preferably 600 mPas or less, still more preferably 500 mPas or less.
The viscosity was measured at 25℃using a B-type rotary viscometer (manufactured by Tokyo industries Co., ltd., rotor No. 2) at a rotation speed of 60rpm for 120 seconds.
The 1 st coating composition preferably further comprises depolymerized acrylic resin particles.
When the coating composition 1 is fired after being applied and dried, the depolymerized acrylic resin particles maintain the binder effect on the fluorine-containing ethylenic polymer particles and slowly decompose, so that the occurrence of shrinkage cracks can be prevented. Therefore, it is necessary for the depolymerizable acrylic resin particles to be melted at or below the melting temperature of the fluoroethylene polymer and to start depolymerization, at least a part of the particles remain at the melting temperature of the fluoroethylene polymer, and most of the particles decompose and volatilize at the firing temperature.
When the dried coating film is heated, the evaporation of the residual nonionic surfactant or the thermal melting of the decomposed volatile and depolymerized acrylic resin particles is started first. The nonionic surfactant needs to remain until at least the completion of the hot melting of the depolymerized acrylic resin particles. If the temperature is further increased, the evaporation or decomposition of the residual nonionic surfactant is completed, and the depolymerization of the depolymerization acrylic resin by the hot melt is started. The depolymerization of the depolymerizable acrylic resin is gradually started from a temperature equal to or lower than the melting temperature of the fluorine-containing ethylenic polymer, and is completed when the depolymerization is completed until the temperature (melting temperature) at which the fluorine-containing ethylenic polymer particles start to thermally melt reaches a firing temperature exceeding the melting temperature of the fluorine-containing ethylenic polymer. Therefore, a large amount of depolymerized acrylic resin can be prevented from remaining in the obtained fluoroethylenic polymer coating film. Since the depolymerizable acrylic resin has tackiness during hot melting and depolymerization proceeds slowly, rapid shrinkage does not occur even when the fluoroethylene-based polymer particles are melted and welded, and occurrence of heat shrinkage cracking can be suppressed.
Therefore, it is preferable that the depolymerization acrylic resin particles remain from the melting point of the fluoroethylene polymer or lower to the temperature (melting temperature) at which the fluoroethylene polymer particles start to melt, and decompose and volatilize at the firing (processing) temperature. For example, it is preferable that 5% or more, particularly 10% or more, at least 50% or more, preferably at least 20% or less remain at the melting temperature of the fluoroethylene polymer, and that only 10% or less, particularly 5% or less remain at the firing (processing) temperature (usually, the temperature exceeding the melting temperature of the fluoroethylene polymer to 415 ℃ C., preferably 360 to 400 ℃ C.), and substantially no remain at the completion of firing. In this respect, the depolymerization (decomposition) temperature of the depolymerizable acrylic resin particles is preferably about 200 ℃ or higher and less than the firing (processing) temperature of the fluorine-containing ethylenic polymer, particularly the melting temperature of the fluorine-containing ethylenic polymer or lower. In the case of acrylic resin particles whose depolymerization (thermal decomposition) temperature exceeds the melting temperature of the fluorine-containing ethylenic polymer and which generate a large amount of decomposed gas, the obtained coating film is likely to have coating film defects such as pinholes.
In particular, from the viewpoint of the balance between the effect of preventing shrinkage cracking and the effect of preventing coloration, it is preferable that about 25 to 50% of the depolymerized acrylic resin remains in the temperature range of 300 to 320 ℃ and about 20 to 10% of the depolymerized acrylic resin remains in the temperature range of 330 to 345 ℃ regardless of the type of resin, and the depolymerized acrylic resin particles satisfying this condition may be used.
Regarding depolymerization, as described in "Polym.Eng.Sci." volume 6, volume 273 (1966) "," Plast.Massa. "volume 75, page 48 (1971)", "degradation of polymer materials" CORONA PUBLISHING CO., LTD., "144 (1958), in general, the more branches in the polymer chain are, the weaker the C-C bond and C-H bond are, and the more oxidative decomposition is likely to occur, resulting in depolymerization. Thus, as the depolymerizable acrylic resin particles of the present disclosure, there may be mentioned methacrylate resins, specifically, for example, there may be mentioned preferably, for example, the following formula (9): CH (CH) 2 ＝C(CH 3 ) A methacrylate homopolymer or a methacrylate copolymer containing a methacrylate monomer represented by COOR (9) (wherein R is an alkyl group or a hydroxyalkyl group having 1 to 5 carbon atoms) as an essential component. Specific examples of the methacrylate-based monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, dimethyl propyl methacrylate, butyl methacrylate, and pentyl methacrylate. Among these, depolymerizable acrylic resins containing butyl methacrylate as a monomer are preferable from the viewpoint of low glass transition temperature and good depolymerizability (degradability).
In addition, even if the polymer is a homopolymer, there is no problem as long as a stable emulsion can be formed, and a monomer having a carboxyl group or a hydroxyl group or the like can be used as a suitable comonomer from the viewpoint of stabilizing the emulsion.
The depolymerizable acrylic resin particles may be, for example, particles produced by emulsion polymerization or the like (depolymerizable acrylic resin emulsion) as they are, and the average particle diameter thereof is preferably 0.1 to 100 μm, particularly preferably 0.2 to 1 μm. If the average particle diameter is less than 0.1. Mu.m, cracks tend to be generated easily, and if it exceeds 100. Mu.m, coating tends to be difficult.
The blending amount of the depolymerized acrylic resin particles is 5 to 25 parts, preferably 7 to 20 parts, and particularly preferably 10 to 15 parts per 100 parts of the fluoroethylene-based polymer (solid content). When the blending amount is less than 5 parts, film formation of the fluoroethylene-based polymer becomes difficult, and when it exceeds 25 parts, the coating film may be colored.
The depolymerized acrylic resin particles are preferably mixed with other components in the form of an emulsion.
The 1 st coating composition may contain other liquid organic compounds having hydrophilic groups, in order to achieve dispersion stability of the coating composition with affinity for water. As the hydrophilic group-containing organic compound, a high boiling point polyol is preferable.
As the high boiling point polyol, a polyol containing no nitrogen atom is preferable because it hardly causes coloration due to thermal decomposition upon firing. The number of hydroxyl groups is preferably 2 to 3. Polyols having a hydroxyl number of 4 or more are mostly solid at room temperature.
Preferred polyhydric alcohols include, for example, 1 or 2 or more of ethylene glycol (boiling point: 198 ℃ C.), 1, 2-propylene glycol (188 ℃ C.), 1, 3-propylene glycol (214 ℃ C.), 1, 2-butanediol (190 ℃ C.), 1, 3-butanediol (208 ℃ C.), 1, 4-butanediol (229 ℃ C.), 1, 5-pentanediol (242 ℃ C.), 2-butene-1, 4-diol (235 ℃ C.), glycerin (290 ℃ C.), 2-ethyl-2-hydroxymethyl-1, 3-propanediol (295 ℃ C.), 1,2, 6-hexanetriol (178 ℃ C./5 mmHg) and the like.
In addition, an organic solvent other than the high boiling point polyol may be used in combination as necessary within a range that does not impair the effects of the present disclosure. Examples of such an organic solvent include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents having 9 to 11 carbon atoms, and the like.
The blending amount of the polyhydric alcohol is 5 to 18 parts, preferably 7 to 15 parts, particularly preferably 7 to 12 parts, per 100 parts of the fluoroethylene-based polymer (solid content). If the amount is less than 5 parts, the effect of preventing the occurrence of cracks becomes weak, and if the amount exceeds 18 parts, the coating film may become cloudy.
The 2 nd coating composition preferably comprises a heat resistant resin (excluding the above-mentioned fluoroethylene-based polymer). The heat-resistant resin may be any resin that is generally considered to have heat resistance, and does not include the fluoroethylene-based polymer. In the present specification, "heat resistance" means a property capable of being continuously used at a temperature of 150 ℃ or higher.
Examples of the heat-resistant resin include polyamide imide resin (PAI), polyimide resin (PI), polyether sulfone resin (PES), polyetherimide resin, aromatic polyether ketone resin (PAEK), aromatic polyester resin, and polyarylene sulfide resin (PAS), and the like, and 1 or 2 or more kinds thereof may be used singly or in combination.
PAI is a resin composed of a polymer having an amide bond and an imide bond in a molecular structure. The PAI is not particularly limited, and examples thereof include resins composed of high molecular weight polymers obtained by the following reactions: reaction of an aromatic diamine having an amide bond in the molecule with an aromatic tetracarboxylic acid such as pyromellitic acid; reaction of aromatic tricarboxylic acid such as trimellitic anhydride with diamine such as 4, 4-diaminophenyl ether or diisocyanate such as diphenylmethane diisocyanate; a reaction of a dibasic acid having an aromatic imide ring in the molecule with a diamine; etc. The PAI is preferably composed of a polymer having an aromatic ring in the main chain, because of excellent heat resistance.
PI is a resin composed of a polymer having an imide bond in a molecular structure. The PI is not particularly limited, and examples thereof include resins composed of high molecular weight polymers obtained by reaction of aromatic tetracarboxylic acid anhydride such as pyromellitic dianhydride and the like. The PI is preferably composed of a polymer having an aromatic ring in the main chain, because of excellent heat resistance.
PES is represented by the general formula:
[ chemical 9]
The resin composed of the polymer of the repeating unit represented. The PES is not particularly limited, and examples thereof include resins composed of polymers obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol.
The aromatic polyether ketone resin is a resin containing a repeating unit composed of an arylene group, an ether group [ -O- ] and a carbonyl group [ -C (=O) - ]. Examples of the aromatic polyether ketone resin include polyether ketone resin (PEK), polyether ether ketone resin (PEEK), polyether ketone resin (PEKK), polyether ether ketone resin (PEEKK), polyether ketone ester resin, and the like. The aromatic polyether ketone resin may be used alone or in combination of 2 or more.
The aromatic polyether ketone resin is preferably at least one selected from the group consisting of PEK, PEEK, PEKK, PEEKK and polyether ketone ester resins, more preferably at least one selected from the group consisting of PEEK and PEKK, and still more preferably PEEK.
PAS is composed of a PAS having the general formula
[ chemical 10]
(wherein Ar represents an arylene group) and a resin comprising a polymer of a repeating unit represented by the formula (I). The PAS is not particularly limited, and examples thereof include polyphenylene sulfide (PPS).
The heat-resistant resin is preferably at least one selected from the group consisting of PAI, PI, PES, an aromatic polyether ketone resin and PAS, more preferably at least one selected from the group consisting of PAI, PI, PES, PEEK, PEKK and PPS, still more preferably at least one selected from the group consisting of PAI, PI and PES, and particularly preferably PAI.
The mass ratio of the fluoroethylene-based polymer to the heat-resistant resin (fluoroethylene-based polymer/heat-resistant resin) is preferably 10/90 to 90/10, more preferably 20/80 or more, still more preferably 30/70 or more, still more preferably 40/60 or more, particularly preferably 50/50 or more, most preferably 55/45 or more, and still more preferably 80/20 or less, still more preferably 70/30 or less.
In the coating composition 2, the content of the fluorine-containing ethylenic polymer is preferably 1 to 30% by mass relative to the coating composition. The content is more preferably 5% by mass or more, still more preferably 10% by mass or more, particularly preferably 15% by mass or more, and still more preferably 25% by mass or less, still more preferably 20% by mass or less, relative to the coating composition.
When the filler (i) is contained in the coating composition 2, the content thereof is 0.1 to 80% by mass, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further more preferably 8% by mass or more, particularly preferably 10% by mass or more, most preferably 12% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less, further preferably 50% by mass or less, relative to the fluorine-containing ethylenic polymer.
When the filler (ii) is contained in the coating composition 2, the content thereof is 0.1 to 120% by mass, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further more preferably 8% by mass or more, particularly preferably 10% by mass or more, most preferably 12% by mass or more, and preferably 100% by mass or less, more preferably 90% by mass or less, further preferably 80% by mass or less, further more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably 50% by mass or less, relative to the fluorine-containing ethylenic polymer.
When the filler (iii) is contained in the coating composition 2, the content thereof is preferably 1 to 150% by mass, more preferably 2% by mass or more, still more preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably 8% by mass or more, still more preferably 10% by mass or more, particularly preferably 12% by mass or more, most preferably 15% by mass or more, and preferably 130% by mass or less, more preferably 110% by mass or less, still more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably 50% by mass or less, relative to the fluorine-containing ethylenic polymer.
The 2 nd coating composition preferably contains at least one selected from the group consisting of the above-mentioned filler (i) and the above-mentioned filler (ii).
In the coating composition 2, the viscosity at 25℃is preferably 50 mPas to 1500 mPas in view of excellent sprayability in spray coating. The viscosity is more preferably 100 mPas or more, still more preferably 150 mPas or more, and still more preferably 700 mPas or less, still more preferably 500 mPas or less.
The viscosity was measured at 25℃using a B-type rotary viscometer (manufactured by Tokyo industries Co., ltd., rotor No. 2) at a rotation speed of 60rpm for 120 seconds.
The coating compositions of the present disclosure and the 1 st and 2 nd coating compositions can be produced, for example, by mixing the essential components in the aqueous dispersion of the fluorine-containing ethylenic polymer and concentrating and diluting the mixture as necessary.
The aqueous dispersion of the fluoroethylene polymer may be prepared by adding a nonionic surfactant to the aqueous dispersion of the fluoroethylene polymer after completion of polymerization, concentrating, diluting, or the like, and the solid content concentration of the fluoroethylene polymer may be adjusted.
In the case where the fluorine-containing ethylenic polymer is PTFE, the PTFE aqueous dispersion can be suitably produced, for example, by a production method for producing an aqueous PTFE dispersion, which comprises the steps of:
step A, emulsion polymerizing TFE in the presence of a fluorine-containing anionic surfactant to obtain a dispersion containing PTFE,
a step B of adding a nonionic surfactant (1) to the dispersion obtained in the step A,
a step C of removing the fluorine-containing anionic surfactant from the dispersion liquid obtained in the step B and further concentrating the dispersion liquid; or a step of concentrating the dispersion obtained in the step B to further remove the fluorine-containing anionic surfactant, and
and step D of adding a nonionic surfactant (2) and a non-fluorine-containing anionic surfactant to the dispersion liquid obtained in step C.
In the present specification, the term "dispersion obtained in step a" is merely intended to mean a dispersion having undergone step a, and may be a dispersion having undergone other treatments or the like after step a. The same applies to steps B to D.
The emulsion polymerization can be carried out, for example, as follows: the emulsion polymerization is carried out by charging an aqueous medium, a fluorine-containing anionic surfactant, a monomer and, if necessary, other additives into a reaction apparatus, stirring the contents of the reaction apparatus, maintaining the reaction apparatus at a specific polymerization temperature, and then adding a specific amount of a polymerization initiator to initiate the polymerization. After the polymerization reaction is started, a monomer, a polymerization initiator, a chain transfer agent, the surfactant, and the like may be additionally added according to the purpose. The surfactant may be added after the polymerization reaction is started.
The polymerization temperature and polymerization pressure in the emulsion polymerization are appropriately determined according to the type of the monomer used, the molecular weight of the target PTFE, and the reaction rate.
For example, the polymerization temperature is preferably 10 to 150 ℃. The polymerization temperature is more preferably 30℃or higher, still more preferably 50℃or higher. And more preferably 120 ℃ or less, and still more preferably 100 ℃ or less.
The polymerization pressure is preferably 0.05 to 10MPa. The polymerization pressure is more preferably 0.3MPa or more, still more preferably 0.5MPa or more. And more preferably 5.0MPa or less, and still more preferably 3.0MPa or less.
The polymerization initiator is not particularly limited as long as it can generate radicals in the polymerization temperature range, and known oil-soluble and/or water-soluble polymerization initiators can be used. It is also possible to further combine with a reducing agent or the like and initiate polymerization in a redox form. The concentration of the polymerization initiator may be appropriately determined depending on the kind of the monomer, the molecular weight of the target PTFE, and the reaction rate.
As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.
Examples of the oil-soluble radical polymerization initiator include known oil-soluble peroxides such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate and the like, peroxy esters such as t-butyl peroxyisobutyrate, t-butyl peroxypivalate and the like, dialkyl peroxides such as di-tert-butyl peroxide and the like, and di (ω -hydro-dodecafluoroheptanoyl) peroxide, di (ω -hydro-tetradecahaloyl) peroxide, di (ω -hydro-hexadecahaloyl) peroxide, di (perfluorobutanoyl) peroxide, di (perfluoropentanoyl) peroxide, di (perfluorohexanoyl) peroxide, di (perfluoroheptanoyl) peroxide, di (perfluorooctanoyl) peroxide, di (perfluorononanoyl) peroxide, di (ω -chloro-hexafluorobutanoyl) peroxide, di (ω -chloro-decafluorohexanoyl) peroxide, di (ω -chloro-tetradecahaloyl) peroxide, di (ω -chloro-dodecafluoroheptanoyl) peroxide, ω -fluoro-dodecafluorodecanoyl peroxide, ω -chloro-octafluorodecanoyl peroxide, and the like, typical examples thereof include di [ perfluoro (or fluorochloroacyl) ] peroxides such as di (tetrachloroundecanoyl) peroxide, di (pentachlorotetradecanoyl) peroxide and di (undecanothirty-difluorotwenty-diacyl) peroxide.
The water-soluble radical polymerization initiator may be a known water-soluble peroxide, and examples thereof include ammonium salts, potassium salts, sodium salts, t-butyl peroxymaleate, t-butyl hydroperoxide, etc. of persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, percarbonic acid, etc. Reducing agents such as sulfites and sulfites may be contained at the same time, and the amount thereof may be 0.1 to 20 times that of the peroxide.
For example, when polymerization is carried out at a low temperature of 30 ℃ or lower, a redox initiator in which an oxidizing agent and a reducing agent are combined is preferably used as the polymerization initiator. Examples of the oxidizing agent include persulfates, organic peroxides, potassium permanganate, manganese triacetate, ammonium cerium nitrate, bromates, and the like. Examples of the reducing agent include sulfite, bisulfite, bromate, diimine, and oxalic acid. Examples of the persulfate include ammonium persulfate and potassium persulfate. The sulfite may be sodium sulfite or ammonium sulfite. In order to increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the combination of redox initiators. Copper salts include copper (II) sulfate, and iron salts Include Iron (II) sulfate.
As the redox initiator, for example, potassium permanganate/oxalic acid, ammonium persulfate/bisulfite/iron (II) sulfate, ammonium persulfate/sulfite, ammonium persulfate/iron (II) sulfate, manganese triacetate/oxalic acid, ceric ammonium nitrate/oxalic acid, bromate/sulfite, bromate/bisulfite, etc., may be carried out, and potassium permanganate/oxalic acid, ammonium persulfate/sulfite/iron (II) sulfate are preferable. In the case of using a redox initiator, either the oxidizing agent or the reducing agent may be charged into the polymerization vessel in advance, and then the other may be continuously or intermittently charged to initiate polymerization. For example, in the case of using potassium permanganate/oxalic acid, oxalic acid is preferably charged into a polymerization vessel, and potassium permanganate is continuously added thereto.
The amount of the polymerization initiator to be added is not particularly limited, and may be an amount (for example, several ppm relative to the concentration of water) of not less than an amount which does not significantly reduce the polymerization rate at one time, sequentially or continuously at the initial stage of polymerization. The upper limit is a range in which heat removal from the apparatus surface can be performed by using the polymerization reaction heat and the reaction temperature can be increased, and the upper limit is more preferably a range in which the polymerization reaction heat can be removed from the apparatus surface.
As the polymerization initiator, a radical polymerization initiator may be used. As the radical polymerization initiator, a peroxide is preferable. The radical polymerization initiator may be the oil-soluble radical polymerization initiator, the water-soluble radical polymerization initiator, or the like, and the water-soluble radical polymerization initiator is preferable. The water-soluble radical polymerization initiator is more preferably a peroxide, further preferably a persulfate, an organic peroxide, or a mixture thereof. Examples of the persulfate include ammonium persulfate and potassium persulfate. Examples of the organic peroxide include disuccinic acid peroxide and dipentaerythritol peroxide. More preferably ammonium persulfate or succinyl peroxide.
In the emulsion polymerization, the water-soluble radical polymerization initiator is preferably used in an amount of 500ppm or less relative to the aqueous medium, more preferably 400ppm or less, still more preferably 300ppm or less, particularly preferably 200ppm or less, and preferably 5ppm or more, more preferably 10ppm or more, still more preferably 20ppm or more.
For example, the water-soluble radical polymerization initiator is preferably ammonium persulfate in an amount of preferably 0.1ppm or more, more preferably 1.0ppm or more, still more preferably 1.5ppm or more, still more preferably 2.0ppm or more, and particularly preferably 2.5ppm or more, relative to the aqueous medium. The amount of ammonium persulfate to be used in the aqueous medium is preferably 50ppm or less, more preferably 40ppm or less, and still more preferably 30ppm or less.
The water-soluble radical polymerization initiator is preferably succinyl peroxide in an amount of 10ppm or more, more preferably 30ppm or more, and still more preferably 50ppm or more, relative to the aqueous medium. The amount of succinyl peroxide is preferably 500ppm or less, more preferably 300ppm or less, and still more preferably 200ppm or less, relative to the aqueous medium.
In the emulsion polymerization, ammonium persulfate and succinyl peroxide are particularly preferably used in combination, and the amounts of ammonium persulfate and succinyl peroxide may be used in combination as the amounts of ammonium persulfate and succinyl peroxide in the case of combination.
In the emulsion polymerization, the radical polymerization initiator may be added continuously or intermittently after the start of the polymerization.
Examples of the chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, and dimethyl succinate, various halogenated hydrocarbons such as isopentane, methane, ethane, propane, isobutane, methanol, ethanol, isopropanol, acetone, various mercaptans, and carbon tetrachloride, and cyclohexane.
Among these, at least one selected from the group consisting of alkanes and alcohols is preferable from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, and the like. The number of carbon atoms of the alkane is preferably 1 to 6, more preferably 1 to 5. The number of carbon atoms of the alcohol is preferably 1 to 5, more preferably 1 to 4. The chain transfer agent is particularly preferably at least one selected from the group consisting of methane, ethane, propane, isobutane, methanol, ethanol, and isopropanol.
The amount of the chain transfer agent is preferably 0.001 to 10000ppm relative to the aqueous medium. The amount of the chain transfer agent is more preferably 0.01ppm or more, still more preferably 0.05ppm or more, particularly preferably 0.1ppm or more, relative to the aqueous medium. Further, the content of the water-based medium is more preferably 1000ppm or less, and still more preferably 500ppm or less.
The chain transfer agent may be added to the reaction apparatus at one time before the start of the polymerization, may be added at one time after the start of the polymerization, may be added in multiple portions during the polymerization, or may be added continuously during the polymerization.
The step (a) is preferably a step of polymerizing TFE and a monomer copolymerizable with TFE.
The monomer copolymerizable with TFE includes the above-mentioned modified monomer, and particularly, at least one monomer selected from the group consisting of PAVE, PFAE, perfluoroallyl ether, and cyclic monomer is preferable, and PAVE is more preferable.
As the PAVE, regarding the perfluoro (alkyl vinyl ether), for example, perfluoro (methyl vinyl ether) [ PMVE ], perfluoro (ethyl vinyl ether) [ PEVE ], perfluoro (propyl vinyl ether) [ PPVE ], perfluoro (butyl vinyl ether) [ PBVE ] and the like are mentioned, and at least one selected from the group consisting of PMVE, PEVE and PPVE is preferable, and PPVE is more preferable.
The PFAE is not particularly limited, and examples thereof include (perfluorobutyl) ethylene [ PFBE ], (perfluorohexyl) ethylene, and the like.
Examples of the perfluoroallyl ether include
A general formula: CF (compact flash) 2 ＝CF-CF 2 -ORf 12
(wherein Rf 12 Represents a perfluorinated organic group).
The Rf described above 12 A perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms is preferable. The perfluoroallyl ether is preferably selected from the group consisting of CF 2 ＝CF-CF 2 -O-CF 3 、CF 2 ＝CF-CF 2 -O-C 2 F 5 、CF 2 ＝CF-CF 2 -O-C 3 F 7 CF (compact flash) 2 ＝CF-CF 2 -O-C 4 F 9 At least one selected from the group consisting of, more preferably, CF 2 ＝CF-CF 2 -O-C 2 F 5 、CF 2 ＝CF-CF 2 -O-C 3 F 7 CF (compact flash) 2 ＝CF-CF 2 -O-C 4 F 9 At least one of the group consisting of CF is further preferred 2 ＝CF-CF 2 -O-CF 2 CF 2 CF 3 。
The cyclic monomer is preferably represented by the general formula (ii):
[ chemical 11]
(wherein X is 2 And X 3 Identical or different, represents a hydrogen atom or a fluorine atom, Y represents-CR 1 R 2 -，R 1 And R is 2 The same or different, and represents a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms). As the vinyl heterocyclic compound represented by the above general formula (ii), for example, X is preferable 2 And X 3 Is a fluorine atom, and preferably R 1 And R is 2 Is a fluoroalkyl group having 1 to 6 carbon atoms.
As the vinyl heterocyclic compound represented by the above general formula (ii), X is preferable 2 And X 3 Is a fluorine atom, R 1 And R is 2 Perfluoro-2, 2-dimethyl-1, 3-dioxole [ PDD ] being a perfluoromethyl group]。
In the step a, as the fluorine-containing anionic surfactant, for example, a fluorine-containing anionic surfactant having a LogPOW of 3.5 or less, preferably a fluorine-containing anionic surfactant having a LogPOW of 3.4 or less, is used, and the fluorine-containing anionic surfactant described in the coating composition of the present disclosure is exemplified.
The step a is preferably a step of obtaining a dispersion of PTFE having a core-shell structure.
For example, a dispersion of PTFE having a core-shell structure can be obtained by polymerizing TFE and, if necessary, a modifying monomer to produce a core (PTFE or modified PTFE), and then polymerizing TFE and, if necessary, a modifying monomer to produce a shell (PTFE or modified PTFE).
In addition, the step a is a step of obtaining a dispersion of a modified polytetrafluoroethylene having a core-shell structure, and preferably includes the steps of: step A-1 of polymerizing TFE and at least one modifying monomer selected from the group consisting of perfluoro (alkyl vinyl ether), (perfluoroalkyl) ethylene and cyclic monomers to produce the core; and a step A-2 of polymerizing at least one selected from the group consisting of hexafluoropropylene and a chain transfer agent in addition to TFE and the modifying monomer to produce the shell.
The step A-2 is more preferably a step of polymerizing TFE and a chain transfer agent.
The shell may be obtained by copolymerizing a modified monomer which is a monomer copolymerizable with TFE, and may be obtained by adding a chain transfer agent at the time of polymerization, or may be obtained by performing both of them.
Regarding the above-mentioned shell, it is preferable to obtain it by using a chain transfer agent, and/or by allowing the following general formula (iii):
F 2 C＝CFO(CF 2 ) n1 X 1 (iii)
(wherein X is 1 Represents a hydrogen atom or a fluorine atom, and n1 represents an integer of 1 to 6) is fluoro (alkyl vinyl ether)Or the following general formula (iv)
CX 4 X 5 ＝CX 6 (CF 2 ) n2 F (iv)
(wherein X is 4 、X 5 And X 6 At least one of the hydrogen atom and the fluorine atom represents a fluorine atom. n2 represents an integer of 1 to 5) and copolymerizing a fluorinated olefin represented by the formula (i).
The chain transfer agent used for producing the shell is not particularly limited as long as it can reduce the molecular weight of PTFE constituting the shell, and examples thereof include water-soluble alcohols, non-peroxidized organic compounds such as hydrocarbons and fluorinated hydrocarbons, water-soluble organic peroxides such as succinyl peroxide [ DSP ], and/or chain transfer agents formed from persulfates such as ammonium persulfate [ APS ] and potassium persulfate [ KPS ]. The chain transfer agent may be any one of at least one non-peroxidized organic compound, water-soluble organic peroxide and persulfate. Among the above chain transfer agents, 1 or 2 or more types of non-peroxidized organic compounds, water-soluble organic peroxides and persulfates, respectively, may be used.
The chain transfer agent is preferably composed of at least 1 selected from the group consisting of water-soluble alcohols having 1 to 4 carbon atoms, hydrocarbons having 1 to 4 carbon atoms, fluorinated hydrocarbons having 1 to 4 carbon atoms, and the like, more preferably at least 1 selected from the group consisting of methane, ethane, n-butane, isobutane, methanol, isopropanol, DSP, APS, and KPS, and even more preferably methanol and/or isobutane, from the viewpoint of good dispersibility and uniformity in the reaction system.
The fluoroolefin represented by the general formula (iv) is preferable as the modifying monomer used for producing the shell.
Examples of the fluoroolefins include perfluoroolefins having 2 to 4 carbon atoms and hydrofluoroolefins having 2 to 4 carbon atoms.
As the above fluoroolefin, perfluoroolefin is preferable, and hexafluoropropylene [ HFP ] is particularly preferable.
The content of the modifier unit derived from the modifying monomer in the shell varies depending on the type of modifying monomer used, but is preferably 0.001 to 0.5 mass%, more preferably 0.005 mass%, still more preferably 0.2 mass%, and still more preferably 0.10 mass% of the total primary particles constituting PTFE, from the viewpoint of stability of the PTFE dispersion. In the case of using HFP as the modifying monomer in the above-mentioned shell, the lower limit is preferably 0.001 to 0.3 mass%, more preferably 0.005 mass%, and even more preferably the upper limit is 0.15 mass% of the entire primary particles constituting PTFE.
The shell may be obtained by either the use of a chain transfer agent or the copolymerization of a modifier, or may be obtained by both the copolymerization of a modifying monomer and the use of a chain transfer agent.
In the case where the fluoro (alkyl vinyl ether) represented by the general formula (iii) is used as a modifying monomer in the PTFE constituting the core, particularly PPVE, the PTFE is preferably obtained by using methanol, isobutane, DSP and/or APS as a chain transfer agent, or copolymerizing HFP and/or PPVE as a modifying agent, and more preferably by using methanol or HFP.
The step a is preferably a step of polymerizing TFE and a modified monomer to produce a core, and then polymerizing a monomer composition containing TFE in the presence of a chain transfer agent to produce a shell. As the modifying monomer and the chain transfer agent, the modifying monomer and/or the chain transfer agent described for PTFE having the core-shell structure can be used.
The core-shell structure is particularly preferably a core-shell structure comprising a core of modified PTFE and a shell of low-molecular-weight PTFE obtained by polymerizing a monomer composition containing TFE in the presence of a chain transfer agent. As described above, by polymerizing a monomer composition containing TFE in the presence of a chain transfer agent, a shell of low molecular weight PTFE can be obtained.
When the PTFE obtained in step a is modified PTFE, the modified PTFE preferably contains 0.050% by mass or more and 1.00% by mass or less of polymerized units (modified monomer units) based on the modified monomer. The modified PTFE preferably contains 99.00 mass% or more and 99.95 mass% or less of polymerized units based on TFE. The modified PTFE described above may be composed of only polymerized units based on TFE and polymerized units based on a modified monomer. The lower limit of the content of the modified monomer unit is more preferably 0.070 mass%, still more preferably 0.10 mass%, still more preferably 0.15 mass%, particularly preferably 0.20 mass%, and particularly preferably 0.25 mass%. The upper limit of the content of the modified monomer unit is preferably 0.90 mass%, more preferably 0.50 mass%, still more preferably 0.45 mass%, still more preferably 0.40 mass%, and particularly preferably 0.35 mass%.
The step a preferably includes the steps of: step 1, adding deionized water, a fluorine-containing anionic surfactant (excluding PFOA or a salt thereof), and a stabilizing aid to a reaction apparatus, removing oxygen, adding TFE, and adding a polymerization initiator; step 2, adding a monomer copolymerizable with TFE; step 3, adding a chain transfer agent; and step 4, cooling after the polymerization is completed, and removing the stabilizing additive.
In the step 1, the fluorine-containing anionic surfactant (excluding PFOA or a salt thereof) may be a fluorine-containing anionic surfactant other than PFOA or a salt thereof, and for example, a fluorine-containing anionic surfactant having a log pow of less than 3.5, preferably a fluorine-containing anionic surfactant having a log pow of 3.4 or less, may be used.
More specifically, the compound represented by the general formula (N 1 ) A compound represented by the general formula (N) above (excluding PFOA or a salt thereof) 2 ) The compound represented by the above general formula (N) 3 ) The compound represented by the above general formula (N) 4 ) The compound represented by the general formula (N) 5 ) At least one compound of the group consisting of the indicated compounds (excluding PFOA or a salt thereof).
More specifically, at least one selected from the group consisting of perfluorocarboxylic acid (I) represented by the above general formula (I) (excluding PFOA or a salt thereof), ω -H perfluorocarboxylic acid (II) represented by the above general formula (II), perfluoropolyether carboxylic acid (III) represented by the above general formula (III), perfluoroalkylene carboxylic acid (IV) represented by the above general formula (IV), perfluoroalkoxy fluorocarboxylic acid (V) represented by the above general formula (V), perfluoroalkylsulfonic acid (VI) represented by the above general formula (VI), ω -H perfluorosulfonic acid (VII) represented by the above general formula (VII), perfluoroalkylene sulfonic acid (VIII) represented by the above general formula (VIII), alkyl alkylene carboxylic acid (IX) represented by the above general formula (IX), fluorocarboxylic acid (X) represented by the above general formula (X), alkoxyfluorosulfonic acid (XI) represented by the above general formula (XI), and compound (XII) represented by the below is exemplified.
In the fluorine-containing anionic surfactant in the step 1, the general formula (N) 1 ) In the case of the compound represented by the formula (N) 1 ) Rf in (f) m The number of carbon atoms in (a) is preferably an integer of 3 to 6. In addition (N) 1a ) M1 in (2) is preferably an integer of 3 to 6. In the case of using the perfluorocarboxylic acid (I), n1 in the general formula (I) is preferably an integer of 3 to 6.
The fluorinated anionic surfactant is particularly preferably a compound selected from the group consisting of fluorinated carboxylic acids having 4 to 7 carbon atoms and optionally having etheric oxygen, and salts thereof. The number of carbon atoms herein refers to the total number of carbon atoms in one molecule. The above-mentioned fluorinated anionic surfactants may be used in combination of two or more.
The fluorinated anionic surfactant is preferably a compound selected from the group consisting of fluorinated carboxylic acids having 4 to 7 carbon atoms and having an etheric oxygen group and salts thereof. The fluorine-containing carboxylic acid having an etheric oxygen is a compound having 4 to 7 carbon atoms, an etheric oxygen in the middle of the main chain carbon chain, and-COOH at the end. The terminal-COOH may also form a salt.
The number of etheric oxygen atoms present in the middle of the main chain is 1 or more, preferably 1 to 4, more preferably 1 or 2.
The number of carbon atoms is preferably 5 to 7.
The fluorinated anionic surfactant is particularly preferably a carboxylic acid or a salt thereof having 6 to 7 carbon atoms in the main chain, 1 to 4 etheric oxygen in the main chain, and a linear, branched or cyclic, partially or completely fluorinated main chain. The "main chain" herein means a continuous chain having the largest number of carbon atoms.
As the aboveThe fluorosurfactant is specifically exemplified by F (CF) 2 ) 7 COOM、F(CF 2 ) 5 COOM、H(CF 2 ) 6 COOM、H(CF 2 ) 7 COOM、CF 3 O(CF 2 ) 3 OCHFCF 2 COOM、C 3 F 7 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )COOM、CF 3 CF 2 CF 2 OCF(CF 3 )COOM、CF 3 CF 2 OCF 2 CF 2 OCF 2 COOM、C 2 F 5 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )COOM、CF 3 OCF(CF 3 )CF 2 OCF(CF 3 )COOM、CF 2 ClCF 2 CF 2 OCF(CF 3 )CF 2 OCF 2 COOM、CF 2 ClCF 2 CF 2 OCF 2 CF(CF 3 )OCF 2 COOM、CF 2 ClCF(CF 3 )OCF(CF 3 )CF 2 OCF 2 COOM、CF 2 ClCF(CF 3 )OCF 2 CF(CF 3 )OCF 2 COOM、
The following formula:
[ chemical 12]
And the like (wherein M is as defined above). The anionic fluorosurfactant may be a mixture of two or more kinds, not a single composition.
In the step 1, examples of the stabilizing additive include the above-mentioned substances, and paraffin is particularly preferable. The paraffin wax may be a liquid, semi-solid or solid at room temperature, and is preferably a saturated hydrocarbon having 12 or more carbon atoms. The melting point of paraffin wax is usually preferably 40 to 65 ℃, more preferably 50 to 65 ℃.
In the step 1, the polymerization initiator described in the step A may be used, and the amount thereof to be added is not particularly limited.
In the step 2, as the monomer copolymerizable with TFE, the above-mentioned modified monomer may be used, and for example, at least one monomer selected from the group consisting of PAVE, PFAE and cyclic monomer is preferable. As PAVE, at least one selected from the group consisting of PMVE, PEVE, and PPVE is preferable. The cyclic monomer is preferably a vinyl heterocyclic compound represented by the general formula (II).
Examples of the PFAE include (perfluorobutyl) ethylene (PFBE) and (perfluorohexyl) ethylene.
In the step 2, the monomer copolymerizable with TFE is preferably added before or after the start of polymerization when the solid content concentration of PTFE is less than 5 mass%. This can give a dispersion of PTFE having a core of modified PTFE.
In the step 2, the method for removing oxygen is not particularly limited, and a conventionally known method can be used.
In the step 3, the amount of the chain transfer agent to be added may be the amount described in the step A.
In the step 3, p1/p2 is preferably 0.60 or more. The ratio p1/p2 is more preferably 0.70 or more, still more preferably 0.80 or more, still more preferably 0.90 or more, particularly preferably 0.95 or more. The upper limit of p1/p2 is not particularly limited, and may be, for example, 0.98.
The above-mentioned p1/p2 represents the proportion of the core to the whole PTFE, and represents the proportion of the TFE fed amount when the modifying monomer or the chain transfer agent is fed during the polymerization with respect to the total fed amount of TFE during the polymerization of PTFE. The above p1 represents the TFE charge amount when the shell is charged, and p2 represents the total TFE charge amount.
In the step 4, the method of cooling and removing the stabilizing additive is not particularly limited, and a conventionally known method can be used.
In addition, in the emulsion polymerization, additives for stabilizing each compound may be used in addition to the surfactant and other compounds having surface activity ability according to the intended use. Examples of the additives include buffers, pH adjusters, stabilization aids, and dispersion stabilizers.
As the stabilizing aid, paraffin wax, fluorine-based oil, fluorine-based solvent, silicone oil, and the like are preferable. The stabilizing aids may be used singly or in combination of 1 or more than 2. As the stabilizing aid, paraffin is more preferable. The paraffin wax may be a liquid, semi-solid or solid at room temperature, and is preferably a saturated hydrocarbon having 12 or more carbon atoms. The melting point of paraffin wax is usually 40 to 65℃and more preferably 50 to 65 ℃.
The amount of the stabilizing additive to be used is preferably 0.1 to 12% by mass, more preferably 0.1 to 8% by mass, based on the mass of the aqueous medium (e.g., deionized water) to be used. The stabilizing additive preferably has sufficient hydrophobicity and is completely separated from the PTFE aqueous emulsion after emulsion polymerization of TFE, and does not become a contaminating component.
The aqueous medium is a reaction medium for polymerization, and means a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water, and for example, a non-fluorinated organic solvent such as alcohol, ether, ketone, and/or a fluorinated organic solvent having a boiling point of 40 ℃ or less.
As the nonionic surfactant (1) added in the step B, a nonionic surfactant represented by the above formula (i) can be used.
The nonionic surfactant (1) is preferably a surfactant represented by the following formula (1):
R 4 -O-A 2 -H (1)
(wherein R is 4 Is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms and having an average methyl number per 1 molecule of 2.0 or more, A 2 A polyoxyalkylene chain having an average oxyethylene unit number of 7.0 to 12.0 and an average oxypropylene unit number of 0.0 to 2.0).
R is as described above 4 Preference is given to the following general formula (1-1):
CHR 41 R 42 - (1-1)
(wherein R is 41 Represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms, R 42 Represents an alkyl group having 1 to 17 carbon atoms, R 41 And R is R 42 An alkyl group having 7 to 17 total carbon atoms). As R as above 41 More particularlyThe hydrogen atom or the alkyl group having 1 to 15 carbon atoms is preferable, the hydrogen atom or the alkyl group having 1 to 12 carbon atoms is more preferable, and the hydrogen atom or the alkyl group having 1 to 10 carbon atoms is still more preferable. In addition, as R 42 More preferably an alkyl group having 1 to 15 carbon atoms, still more preferably an alkyl group having 1 to 14 carbon atoms, and still more preferably an alkyl group having 1 to 13 carbon atoms.
R is as described above 4 Alkyl groups having 8 to 18 carbon atoms and having an average methyl number of 2.5 or more are preferable. R is as described above 4 The average number of methyl groups in (a) is more preferably 3.0 or more, still more preferably 3.5 or more, still more preferably 4.0 or more. In addition, R 4 The average number of methyl groups in (a) is preferably 12 or less, more preferably 10 or less, and further preferably 8 or less.
In the formula (1), R 4 Preferably trimethylnonyl, more preferably 2,6, 8-trimethyl-4-nonyl.
R 4 In the case of 2,6, 8-trimethyl-4-nonyl, the average number of ethylene oxide units is preferably 10.0 to 10.5. In this case, the average propylene oxide unit number was 0.0.
The removal of the fluorine-containing anionic surfactant in step C is preferably performed by bringing the aqueous dispersion into contact with an anion exchange resin.
The anion exchange resin in step C is not particularly limited, and known ones can be used. The method of contacting the anion exchange resin may be a known method.
Examples of the anion exchange resin include resins having-N as a functional group + X - (CH 3 ) 3 Strongly basic anion exchange resins having groups (X represents Cl or OH) with-N + X - (CH 3 ) 3 (C 2 H 4 OH) group (X is the same as above), and the like. Specifically, examples thereof include anion exchange resins described in International publication No. 99/62858, international publication No. 03/020836, international publication No. 2004/078836, international publication No. 2013/027850, and International publication No. 2014/084399.
As the cation exchange resin does not containThere are specific limitations, and examples thereof include those having-SO as a functional group 3 - Strongly acidic cation exchange resins having-COO as functional group - Among them, strongly acidic cation exchange resins are preferred, and H is more preferred from the viewpoint of removal efficiency + Strongly acidic cation exchange resins.
The "mixed bed composed of a cation exchange resin and an anion exchange resin" is not particularly limited, and includes a case where both are packed in the same column, a case where both are packed in different columns, a case where both are dispersed in an aqueous dispersion, and the like.
The removal of the fluorine-containing anionic surfactant in step C can be performed by concentration. As described in International publication No. 2005/042593, the concentration step may be performed 2 or more times.
Therefore, in step C, the dispersion obtained in step B may be concentrated 2 or more times.
In addition, the step C is preferably performed by bringing the aqueous dispersion into contact with an anion exchange resin.
As the concentration method in the above step C, a known method is used. Specifically, methods described in international publication No. 2007/046482 and international publication No. 2014/084399 are mentioned.
Examples thereof include phase separation, centrifugal sedimentation, cloud point concentration, electric concentration, electrophoresis, filtration treatment using ultrafiltration, filtration treatment using reverse osmosis membrane (RO membrane), nanofiltration treatment, and the like. The concentration may be such that the concentration of PTFE is 50 to 70% by mass, depending on the application. By concentration, the stability of the dispersion may be impaired, so that a nonionic surfactant may be further added in step C. The nonionic surfactant in step C is the same as in the coating composition of the present disclosure.
Further, a dispersion stabilizer other than the nonionic surfactant may be used as needed. The total amount of the dispersion stabilizer is 0.5 to 20% by mass based on the mass of the solid component of PTFE. If the amount is less than 0.5 mass%, the dispersion stability may be deteriorated, and if it exceeds 20 mass%, the dispersion effect commensurate with the amount present may not be obtained, and it is not practical. The lower limit of the dispersion stabilizer is more preferably 2% by mass, and the upper limit is more preferably 12% by mass.
By the above-described concentration operation, even in the case of using a fluorosurfactant in the polymerization, the fluorosurfactant in the aqueous dispersion can be removed.
As the above concentration, cloud point concentration is preferable. The cloud point concentration is preferably performed by heating at a temperature of 5 ℃ or higher below the cloud point of the nonionic surfactant, for example. More specifically, it is preferable that the liquid phase be allowed to stand after heating at a temperature of 5℃or higher below the cloud point of the nonionic surfactant, and separated into a supernatant liquid phase and a concentrated phase.
The concentration may be performed only 1 time, or may be performed 2 or more times.
Step D is a step of adding a nonionic surfactant (2) and a non-fluorine-containing anionic surfactant to the dispersion liquid obtained in step C.
The order of adding the non-ionic surfactant (2) and the non-fluorine-containing anionic surfactant is not limited, and the non-fluorine-containing anionic surfactant may be added after the non-ionic surfactant (2), the non-ionic surfactant (2) may be added after the non-fluorine-containing anionic surfactant is added, or the non-fluorine-containing anionic surfactant and the non-ionic surfactant may be added simultaneously.
The addition of the nonionic surfactant (2) and the non-fluorinated anionic surfactant may be performed a plurality of times, or the addition of the nonionic surfactant (2) and the addition of the non-fluorinated anionic surfactant may be performed alternately a plurality of times.
As the nonionic surfactant (2) added in step D, a nonionic surfactant represented by the above formula (i) can be used. The nonionic surfactant (2) is preferably a surfactant represented by the following formula (2):
R 5 -O-A 3 -H(2)
(wherein R is 5 Is per one1 molecule of a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms and an average methyl number of 2.0 or more, A 3 A polyoxyalkylene chain having an average oxyethylene unit number of 10.0 to 12.0).
R 5 Preference is given to the following general formula (2-1):
CHR 51 R 52 - (2-1)
(wherein R is 51 Represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms, R 52 Represents an alkyl group having 1 to 17 carbon atoms, R 51 And R is R 52 An alkyl group having 7 to 17 total carbon atoms). As R as above 51 More preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, still more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and still more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. In addition, as R 52 More preferably an alkyl group having 1 to 15 carbon atoms, still more preferably an alkyl group having 1 to 14 carbon atoms, and still more preferably an alkyl group having 1 to 13 carbon atoms.
R is as described above 5 Alkyl groups having 8 to 18 carbon atoms and having an average methyl number of 2.5 or more are preferable. R is as described above 5 The average number of methyl groups in (a) is more preferably 3.0 or more, still more preferably 3.5 or more, still more preferably 4.0 or more. R is R 5 The upper limit of the average number of methyl groups in (a) is preferably 12 or less, more preferably 10 or less, and further preferably 8 or less.
In the formula (2), R 5 Preferably trimethylnonyl, more preferably 2,6, 8-trimethyl-4-nonyl.
R 5 In the case of 2,6, 8-trimethyl-4-nonyl, the average number of ethylene oxide units is preferably 10.1 to 11.0. In this case, the average propylene oxide unit number was 0.0.
The step D is preferably a step of adding the nonionic surfactant (2) so that the concentration of the nonionic surfactant in the dispersion is 4 to 12 mass% relative to polytetrafluoroethylene. More preferably, the addition is performed so that the concentration is 5% by mass or more, still more preferably 10% by mass or less, and still more preferably 8% by mass or less.
Examples of the non-fluorinated anionic surfactant added in step D include alkyl sulfonate, alkyl sulfate, alkylaryl sulfate, and salts thereof; fatty acids (aliphatic carboxylic acids) and salts thereof; alkyl phosphate, alkylaryl phosphate or salts thereof; and the like, with alkyl sulfonates, alkyl sulfates, aliphatic carboxylic acids or salts thereof being preferred.
More preferably at least one selected from the group consisting of alkyl sulfate and salts thereof and fatty acid and salts thereof.
As the alkyl sulfate and its salt, ammonium lauryl sulfate, sodium lauryl sulfate, or the like is preferable.
The fatty acid and its salt are preferably succinic acid, capric acid, undecylenic acid, lauric acid, hydrogenated dodecanoic acid or their salts.
The content of the non-fluorine-containing anionic surfactant is preferably 50 to 5000ppm relative to PTFE.
The lower limit of the amount of the non-fluorinated anionic surfactant to be added is more preferably 50ppm, still more preferably 100ppm, still more preferably 200ppm. If the amount is too small, the viscosity adjusting effect is insufficient.
The upper limit of the amount of the non-fluorinated anionic surfactant to be added is more preferably 4000ppm, still more preferably 3000ppm, still more preferably 2000ppm, particularly preferably 1000ppm. If the amount is too large, the viscosity may be increased, and in particular, the viscosity at high temperature may be increased. In addition, foaming may be increased.
The above production method preferably further comprises a step of adding a preservative to the aqueous dispersion. As the preservative, the one described in the coating composition of the present disclosure can be mentioned.
The above production method preferably further includes a step of adding a paint raw material. Examples of the raw material of the paint include additives which can be added to the paint. Specifically, examples thereof include pigments (extender pigments, flake pigments, etc.), pigment dispersants, thickeners, leveling agents, film forming aids, solid lubricants, anti-settling agents, moisture absorbers, surface regulators, thixotropic agents, viscosity modifiers, anti-gelling agents, ultraviolet absorbers, HALS (light stabilizers), gloss control agents, plasticizers, anti-blooming agents, anti-skinning agents, anti-scratch agents, rust inhibitors, mildewcides, antibacterial agents, antioxidants, flame retardants, anti-dripping agents, antistatic agents, silane coupling agents, carbon black, various reinforcing materials, various extender materials, conductive fillers, colloidal silica, metal powders such as gold, silver, copper, platinum, stainless steel, and the like.
The additive may be an additive other than colloidal silica.
The content of the coating material is not particularly limited, and may be appropriately set according to the application.
The above production method may further include a step of recovering the PTFE aqueous dispersion obtained by polymerization.
The aqueous dispersion in the case where the fluoroethylene polymer is a melt-processible fluororesin can be produced by a known production method such as emulsion polymerization.
The coating film (coating film) may be formed by coating the coating composition of the present disclosure or the 1 st or 2 nd coating composition. The present disclosure also provides a coating formed from the coating composition of the present disclosure or the 1 st or 2 nd coating composition.
The coating film of the present disclosure may be formed, for example, by applying the coating composition of the present disclosure or the 1 st or 2 nd coating composition, preferably the coating composition of the present disclosure or the 2 nd coating composition, to a substrate. The material of the base material is not particularly limited, and examples thereof include metals such as elemental metals including iron, aluminum, stainless steel, copper, and alloys thereof; non-metallic inorganic materials such as enamels, glasses, ceramics, etc. Examples of the alloy include aluminum alloy and stainless steel. As the material of the base material, a metal is preferable, and an aluminum alloy, aluminum, or stainless steel is more preferable. In order to improve the adhesion, it is preferable to roughen the surface of the substrate by a sand blast method or the like or to perform a chemical treatment such as an alumite treatment.
As the coating method, various coating methods similar to the conventional methods can be used. Examples thereof include dipping, spraying, roll coating, doctor blade, flow coating, spin coating, and the like.
The coating composition applied to the substrate may be dried. The drying may be carried out under usual conditions, for example, at room temperature to 80℃and preferably at 80 to 100℃for 5 minutes to 1 hour.
The dried film may be fired as needed. The firing temperature and time vary depending on the type of the fluoroethylene polymer, the melting temperature, etc., and are usually from 360 to 420℃for 5 to 30 minutes, preferably from 360 to 380℃for 10 to 30 minutes, at or above the melting temperature of the fluoroethylene polymer in the case of PTFE.
The thickness of the coating film of the present disclosure is preferably 20 μm or more, and preferably 100 μm or less.
The laminated coating film can also be obtained by applying the coating composition of the present disclosure or the 1 st or 2 nd coating composition, preferably the coating composition of the present disclosure or the 1 st coating composition, to a coating film formed of another coating composition. The present disclosure also provides a laminated coating film comprising a coating film formed from the coating composition of the present disclosure or the 1 st or 2 nd coating composition.
The laminated coating film of the present disclosure can be produced by a method (2-coat 2-bake method, 3-coat 3-bake method) of coating, drying, and baking the coating composition of the present disclosure or the 1 st or 2 nd coating composition after coating, drying, and baking the other coating composition; the coating composition of the present disclosure or the 1 st or 2 nd coating composition may be prepared by a method (2-coat 1-bake method, 3-coat 2-bake method) in which the other coating compositions are applied and dried, and then the coating compositions are applied and dried, and both are fired at the same time.
The present disclosure also provides a coated article having the film of the present disclosure or the laminated film of the present disclosure. Examples of the coated article include: frying pans, baking trays, pressure cookers, other cooking devices such as various cookers, electric cookers, rice cake machines, ovens, heating plates, bread baking molds, kitchen knives, electric heating plates, air fryers, and the like; food containers such as electric kettles, thermos cups and ice making trays; stirring roller, calendaring roller, conveyor, hopper and other food industry components; industrial products such as rolls for office automation equipment [ OA ], OA belts, OA separating claws, paper making rolls, and calender rolls for film production; demolding a mold such as a mold for molding foamed styrene, a mold, a stripper for manufacturing plywood and decorative boards, and the like; kitchen articles such as a range hood; frozen food manufacturing devices such as conveyor belts; tools such as saw, file, die, drill, etc.; household articles such as flatirons, scissors, kitchen knives and the like; metal foil, wire; sliding bearings for food processors, packaging machines, textile machines, etc.; sliding parts of camera and clock; pipe, valve, bearing, etc., snow shovel, spade, chute, ship bottom, boiler, industrial vessel (particularly semiconductor industrial vessel).
Of these, a metal cooking device is preferred, and a frying pan is more preferred.
Examples
The present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.
The respective values of examples and comparative examples were measured by the following methods.
< average primary particle diameter >
A calibration curve was prepared by diluting an aqueous PTFE dispersion with water until the solid content became 0.15% by mass, and measuring the transmittance per unit length of 550nm of the projected light with respect to the resulting diluted aqueous dispersion and the number of the standard length average primary particle diameters determined from the measurement of the alignment diameters by a transmission electron micrograph. Using this calibration curve, the average primary particle diameter was determined from the measured transmittance of each sample for 550nm projected light.
< solid content concentration (P) >)
About 1g (Xg) of the sample was placed in an aluminum cup having a diameter of 5cm, dried at 110℃for 30 minutes, further dried at 300℃for 30 minutes, based on the resulting heated residue (Zg), according to the formula: p=z/x×100 (mass%) to determine the solid content concentration (P).
< Standard Specific Gravity (SSG) >)
The sample molded according to ASTM D4895-89 was used and was measured by the water displacement method according to ASTM D-792.
< content of modified monomer >
Regarding the PPVE content, a film disk was produced by press molding PTFE powder, and 995cm was measured for infrared absorbance obtained by FT-IR measurement of the film disk -1 Is/935 cm -1 The ratio of absorbance of (2) was multiplied by 0.14 to obtain the PPVE content.
< fluorosurfactant concentration >
The solid content of the aqueous dispersion was measured, and an amount of the aqueous dispersion corresponding to 1.5g of the PTFE solid content was weighed in a 100mL screw tube. Thereafter, water and methanol were added so that the extraction solvent was 37g of water/methanol=10/90 mass% to be combined with the water contained in the aqueous dispersion, and shaking was sufficient until precipitation. The liquid phase was extracted, and centrifuged at 4000rpm for 1 hour to extract the supernatant.
The fluorosurfactant in the extract is measured by means of a liquid chromatograph mass spectrometer (Waters, LC-MS acquisition UPLC/TQD). The measurement device configuration and LC-MS measurement conditions are shown in Table 1.
TABLE 1
The calibration curve used for calculation of the fluorosurfactant concentration was obtained under the following conditions.
5 grades of 1ng/mL to 100ng/mL of a known concentration of fluorosurfactant in methanol standard solution were prepared and measured using a liquid chromatograph mass spectrometer (Waters, LC-MS ACQUITY UPLC/TQD). A and b are obtained from the sample concentrations and peak integrated values by using the first approximation by the following relational expression (3).
A＝a×X+b (3)
A: peak area of fluorosurfactant
X: concentration of fluorosurfactant (ng/mL)
The lower limit of the quantification is 100 ppb by mass.
< content of nonionic surfactant (N) >)
About 1g (Xg) of the sample was charged into an aluminum cup having a diameter of 5cm, heated at 110℃for 30 minutes to obtain a heated residue (Yg), and the obtained heated residue (Yg) was further heated at 300℃for 30 minutes to obtain a heated residue (Zg) represented by the formula: n= [ (Y-Z)/X ] ×100 (mass%) was calculated, and the stabilizer was subtracted from the obtained amount, and the obtained amount was taken as the content of the nonionic surfactant. The stabilizers were calculated based on the amount added at the time of preparation.
< average number of methyl groups per 1 molecule >
Adding equal amount of methanol into PTFE aqueous dispersion, performing Soxhlet extraction, and using the extractive solution 1 H-NMR was measured to determine the average number of methyl groups per 1 molecule.
The average molecular structures of the surfactants used in examples and comparative examples are shown below.
Surfactant (a): c (C) 13 H 27 O(CH 2 CH 2 O) 8 H (average number of methyl groups per 1 molecule 4.0), HLB13.30, cloud point 60 DEG C
Surfactant (b): c (C) 13 H 27 O(CH 2 CH 2 O) 10 H (average number of methyl groups per 1 molecule 4.0), HLB13.80, cloud point 71℃C
Surfactant (c): tergitolTMN-100X
C 12 H 25 O(CH 2 CH 2 O) 10 H (average number of methyl groups per 1 molecule of 5.0), HLB of 14.00, cloud point of 65 DEG C
Surfactant (d): tergitol TMN-10
C 12 H 25 O(CH 2 CH 2 O) 11 H (average number of methyl groups per 1 molecule of 5.0), HLB of 14.40, cloud point of 76 DEG C
The Tergitol TMN-100X was a mixture of Tergitol TMN-6 and Tergitol TMN-10, and the composition ratio was as follows.
TMN-6: TMN-10=30:70 (weight ratio)
TMN-6 structural formula
C 12 H 25 O(CH 2 CH 2 O) 8 H (average number of methyl groups per 1 molecule of 5.0), HLB of 13.10, cloud point of 36 DEG C
Synthesis example 1
After replacing 1L of the autoclave with nitrogen, 16.5g of dehydrated tetramethylurea and 220g of diethylene glycol dimethyl ether were charged and cooled. 38.5g of carbonyl fluoride was charged, and 100g of hexafluoropropylene oxide was introduced thereinto and stirred. Thereafter, 38.5g of carbonyl fluoride and 100g of hexafluoropropylene oxide were additionally charged. Thereafter, the same amounts of carbonyl fluoride and hexafluoropropylene oxide were further charged. After the reaction, the reaction mixture was taken out and separated to obtain a lower reaction product.
To a 6L autoclave, 1000ml of tetraethyleneglycol dimethyl ether and CsF (75 g) were added, and the inside of the autoclave was replaced with nitrogen. Thereafter, the autoclave was cooled, 2100g of the reaction product obtained above was charged, and hexafluoropropylene oxide was introduced into the autoclave to initiate the reaction. Finally 1510g of hexafluoropropylene oxide was charged. Thereafter, the content was withdrawn and separated into an upper layer and a lower layer by a separating funnel. 1320g for the upper layer and 3290g for the lower layer. And rectifying the lower layer.
Then, 1000g of pure water was added to 1000g of a distillate obtained by rectifying the lower layer, and hydrolysis was performed. Thereafter, the organic layer (lower layer) was recovered by separating the liquid using a separating funnel. The recovered organic layer (lower layer) was washed with sulfuric acid water. The washed organic layer was subjected to simple distillation to obtain a distillate. Further, 500g of the distillate obtained above was added dropwise to an aqueous solution of 76g of 28wt% aqueous ammonia solution and 600g of pure water. After the completion of the dropwise addition, 28wt% aqueous ammonia solution was added thereto to adjust the pH to 7. It was freeze-dried, whereby a white solid was obtained.
Production example 1
To a SUS-made reactor having an internal volume of 6L and equipped with a stirrer, 3580g of deionized water, 160g of paraffin wax, and 4.7g of the white solid obtained in Synthesis example 1 as a fluorosurfactant were charged. Then, the contents of the reactor were stirred by purging with TFE while heating the contents to 70 ℃. 6.5g of perfluoropropyl vinyl ether (PPVE) was pressed into the reactor using TFE. 50mg of Ammonium Persulfate (APS) dissolved in 20g of deionized water as an initiator was charged into the reactor to bring the pressure to 1.5MPaG. TFE was added at a constant pressure of 1.5MPaG. The reaction was continued by injecting 0.5g of methanol into the reactor at the time point when the TFE consumed in the reaction reached 1466 g. The TFE supply was stopped at the point when the TFE consumption in the reaction reached 1543g, and the stirring was stopped to terminate the reaction. Thereafter, the reactor was vented until the pressure in the reactor reached normal pressure, and the contents were taken out of the reactor and cooled. Paraffin is removed to obtain modified PTFE aqueous dispersion 1-1.
The resulting aqueous dispersion 1-1 had a solid content concentration of 30.0% by mass and an average primary particle diameter of 272nm. The PTFE obtained is a modified PTFE having a core-shell structure with a shell of low molecular weight PTFE. The resulting modified PTFE aqueous dispersion 1-1 was diluted with deionized water to a solid content of about 10 mass%, coagulated under high-speed stirring, and the coagulated wet powder was dried at 150℃for 10 hours to obtain a modified PTFE powder. The standard specific gravity of the obtained modified PTFE powder was 2.167 and the PPVE content was 0.28% by mass.
To the aqueous dispersion 1-1, a surfactant (a) was added as a nonionic surfactant to prepare a dispersion having a nonionic surfactant concentration of 10 parts by mass relative to 100 parts by mass of the modified PTFE. Subsequently, 250ml of an OH-type anion exchange resin (trade name Amberjet 4002, manufactured by Rohm and Haas Co., ltd.) was packed into a column having a diameter of 20mm, and the dispersion was introduced at SV=1. Further, a surfactant (a) was added to the aqueous dispersion obtained by passing through the liquid, and the mixture was kept at 65℃for 3 hours so as to give a supernatant phase and a concentrated phase, with respect to 100 parts by mass of PTFE, in 16 parts by mass. Recovering the concentrated phase to obtain modified PTFE aqueous dispersion 1-2.
The solid content concentration of the obtained modified PTFE aqueous dispersion 1-2 was 68.3% by mass, the content of the nonionic surfactant was 2.7% by mass relative to the modified PTFE, and the fluorine-containing surfactant concentration was 420ppb relative to the modified PTFE aqueous dispersion.
To the obtained modified PTFE aqueous dispersion 1-2, a surfactant (b) was added in an amount of 2.3% by mass relative to the modified PTFE, and 500ppm of ammonium lauryl sulfate relative to the modified PTFE was added, and deionized water and aqueous ammonia were further added to obtain PTFE aqueous dispersion A.
The solid content concentration (% by mass) and the content (% by mass) of each component with respect to PTFE of the obtained PTFE aqueous dispersion a are shown in table 2.
Production example 2
An aqueous dispersion 2-1 of modified PTFE was obtained in the same manner as in production example 1, except that the reaction was continued without injecting methanol into the reactor at the time when the TFE consumed in the reaction reached 1466 g.
The solid content concentration of the obtained modified PTFE aqueous dispersion 2-1 was 30.0 mass%, and the average primary particle diameter was 270nm. The PTFE obtained is a modified PTFE having no core-shell structure. A modified PTFE powder was obtained from the obtained modified PTFE aqueous dispersion 2-1 in the same manner as in production example 1. The standard specific gravity of the obtained modified PTFE powder was 2.163 and the PPVE content was 0.28 mass%.
Modified PTFE aqueous dispersion 2-2 and PTFE aqueous dispersion B were obtained in the same manner as in production example 1, except that modified PTFE aqueous dispersion 1-1 was changed to modified PTFE aqueous dispersion 2-1.
The solid content concentration (% by mass) and the content (% by mass) of each component with respect to PTFE of the obtained PTFE aqueous dispersion B are shown in table 2. The fluorosurfactant concentration was 430 ppb by mass relative to the PTFE aqueous dispersion B.
Production example 3
3500g of deionized water, 100g of paraffin wax, and 5.3g of a white solid as a fluorosurfactant were charged to a SUS-made reactor with stirring blade having an inner capacity of 6L. Then, the contents of the reactor were stirred by purging with TFE while heating the contents to 70 ℃. TFE was introduced under pressure to an internal pressure of 0.78MPaG, and 10g of an aqueous solution of 0.6 mass% Ammonium Persulfate (APS) was introduced to initiate the reaction. As polymerization proceeds, the pressure in the polymerization system decreases, and therefore TFE is continuously added, and the internal pressure is maintained at 0.78mpa g, and the reaction is continued.
The stirring and TFE supply were stopped at the point when the TFE consumption in the reaction reached 1200g, and the stirring was stopped to terminate the reaction. Thereafter, the reaction vessel was vented until the pressure in the reaction vessel reached normal pressure, and the contents were taken out of the reaction vessel and cooled. Paraffin wax was removed to obtain PTFE aqueous dispersion 3-1.
The solid content concentration of the obtained PTFE aqueous dispersion 3-1 was 25.3% by mass, and the average primary particle diameter was 256nm. The PTFE obtained was PTFE having no core-shell structure. PTFE powder was obtained from the obtained PTFE aqueous dispersion 3-1 in the same manner as in production example 1. The standard specific gravity of the obtained PTFE powder was 2.210.
An aqueous PTFE dispersion 3-2 and an aqueous PTFE dispersion C were obtained in the same manner as in production example 1, except that the aqueous modified PTFE dispersion 1-1 was changed to an aqueous PTFE dispersion 3-1.
The solid content concentration (% by mass) and the content (% by mass) of each component with respect to PTFE of the obtained PTFE aqueous dispersion C are shown in table 2.
Production example 4
To a SUS-made reactor having an internal volume of 6L and equipped with a stirrer, 3540g of deionized water, 94g of paraffin wax, and 5.4g of the white solid obtained in Synthesis example 1 as a fluorosurfactant were charged. Then, the contents of the reactor were stirred by purging with TFE while heating the contents to 70 ℃. 0.78g of perfluoropropyl vinyl ether (PPVE) was pressed into the reactor using TFE. 250.6mg of succinyl peroxide (DSP) dissolved in 20g of deionized water and 10.7mg of Ammonium Persulfate (APS) dissolved in 20g of deionized water as an initiator were injected into the reactor to bring the reactor to a pressure of 0.90MPaG. The polymerization was observed to be initiated by a decrease in pressure after initiator injection. TFE was added to the reactor and the pressure was maintained at a constant 0.90MPaG. The reaction was continued by injecting 1.0g of methanol into the reactor at the time point when the TFE consumed in the reaction reached 1380 g. The supply of TFE was stopped at the point when the consumption of TFE in the reaction reached 1534g, and the stirring was stopped to terminate the reaction. Thereafter, the reactor was vented until the pressure in the reactor reached normal pressure, and the contents were taken out of the reactor and cooled. Paraffin wax was removed to obtain PTFE aqueous dispersion 4-1.
The resulting aqueous dispersion 4-1 had a solid content concentration of 30.0% by mass and an average primary particle diameter of 254nm. The PTFE obtained is a modified PTFE having a core-shell structure with a shell of low molecular weight PTFE. A modified PTFE powder was obtained from the obtained PTFE aqueous dispersion 4-1 in the same manner as in production example 1. The standard specific gravity of the obtained modified PTFE powder was 2.174 and the PPVE content was 0.046 mass%.
To the aqueous dispersion 4-1, a surfactant (c) was added as a nonionic surfactant to prepare a dispersion having a nonionic surfactant concentration of 10 parts by mass relative to 100 parts by mass of PTFE. Subsequently, 250ml of an OH-type anion exchange resin (trade name: amberjet AMJ4002, manufactured by Rohm and Haas Co., ltd.) was packed into a column having a diameter of 20mm, and the dispersion was introduced at SV=1. Further, a surfactant (c) was added to the aqueous dispersion obtained by passing the liquid through so as to be 20 parts by mass relative to 100 parts by mass of PTFE, and the mixture was kept at 65℃for 3 hours, and separated into a supernatant phase and a concentrated phase. The concentrated phase was recovered to obtain PTFE aqueous dispersion 4-2.
The solid content concentration of the obtained PTFE aqueous dispersion 4-2 was 71.5% by mass, the content of the nonionic surfactant was 2.7% by mass relative to PTFE, and the fluorine-containing surfactant concentration was 480 ppb by mass relative to the PTFE aqueous dispersion.
To the PTFE aqueous dispersion 4-2 thus obtained, a surfactant (c) was added so as to be 4.0 mass% with respect to PTFE, a surfactant (D) was further added so as to be 2.0 mass% with respect to PTFE, ammonium lauryl sulfate was added so as to be 500ppm with respect to PTFE, and deionized water and aqueous ammonia were further added to obtain PTFE aqueous dispersion D. The solid content concentration (% by mass) and the content (% by mass) of each component with respect to PTFE of the obtained PTFE aqueous dispersion D are shown in table 2.
Further, an equal amount of methanol was added to the obtained PTFE aqueous dispersion D, followed by Soxhlet extraction, and the extract was measured by 1H-NMR, whereby the average number of alkylene oxide units was 10.4.
Production example 5
An aqueous dispersion 5-1 of modified PTFE was obtained in the same manner as in production example 4, except that the reaction was continued without injecting methanol into the reactor at the time when the amount of TFE consumed in the reaction reached 1380 g.
The solid content concentration of the obtained PTFE aqueous dispersion was 30.0 mass%, and the average primary particle diameter was 252nm. The PTFE obtained is a modified PTFE having no core-shell structure. A modified PTFE powder was obtained from the obtained modified PTFE aqueous dispersion 5-1 in the same manner as in production example 1. The standard specific gravity of the obtained modified PTFE powder was 2.170, and the PPVE content was 0.046 mass%.
An aqueous PTFE dispersion 5-2 and an aqueous PTFE dispersion E were obtained in the same manner as in production example 4, except that the aqueous PTFE dispersion 5-1 was changed to an aqueous PTFE dispersion 4-1.
The solid content concentration (% by mass) and the content (% by mass) of each component with respect to PTFE of the obtained PTFE aqueous dispersion E are shown in table 2.
TABLE 2
Example 1
The following components were mixed in the order described.
(A) 68.0 parts of PTFE aqueous dispersion A obtained in production example 1
(B) 13.0 parts of depolymerized acrylic resin particle emulsion (butyl methacrylate resin, average particle size: 0.3 μm, solid content: 40% by mass)
(C) Nonionic surfactant A (DispanolTOC (50% aqueous solution) manufactured by Polyoxyethylene tridecyl ether, nikko Co., ltd.) 5.0 parts
(D) 8.0 parts of organic solvent (ethylene glycol)
(E) Amine (Ammonia) 0.2 part
(F) 5.8 parts of water
(G) 2.3 parts of filling material (SiC, new Mohs hardness 13)
The following properties were investigated for the resulting coating composition. The results are shown in Table 3.
< viscosity >
The viscosity at 25℃was measured using a type B rotary viscometer (manufactured by Dong machine industries Co., ltd., rotor No. 2) at a rotation speed of 60rpm for 120 seconds.
<pH>
The pH at 25℃was measured by using a glass electrode (manufactured by horiba, ltd.) in accordance with JISK 6893.
< storage stability >
500g of the coating composition was placed in a polyethylene bottle, and the bottle was left to stand in a constant temperature bath at 40℃for 1 month, and the redispersibility was evaluated. A150 mesh wire mesh was used for the evaluation, and the total passage was marked as "O" and the presence of the residue on the wire mesh was marked as "X".
< stirring stability >
A container containing 250ml of 200ml of the coating composition was immersed in a water tank at 40℃and a stirring blade (spiral 4 blades) was rotated at 300rpm, and the time until aggregates were generated or solidified in the coating composition was measured and used as a gelation time.
< physical Properties of coating film >
(cracking)
The resulting coating composition was applied by spraying onto an unglazed aluminum plate and dried at 80 ℃ for 15 minutes. The surface of the obtained dried coating film was observed with an optical microscope to examine the presence or absence of occurrence of cracks.
The dried film was then fired at 380℃for 20 minutes to form a molten film. The following physical properties of the coating film were examined for the coating film.
(appearance of coating film)
The surface of the coating film was observed by an optical microscope.
(Pencil hardness)
Evaluation was performed at 25℃according to the method described in JIS K5600.
(crack limiting film thickness)
The film thickness was variously changed, and the film thickness at which the crack starts to occur was defined as the crack limit film thickness.
(coloring)
The coating film was visually observed.
(spray gun blockage)
In the rock Tian Penqiang W88 (nozzle diameter 1.5 mm), the discharge valve was reversed by 1 turn at 9.8N (5 kgf), and the trigger switch was turned back and forth to apply intermittently with the valve fully closed, and the number of times that no paint was discharged from the spray gun was counted.
(white spots)
In rock Tian Penqiang W88 (nozzle diameter: 1.5 mm), the discharge valve was reversed 1 turn at 9.8N (5 kgf), and under the setting of the full-closed valve, the trigger switch was intermittently applied to 10 sheets of 20 cm. Times.60 cm black kraft paper, and the number of times of white spot ejection was counted visually.
(abrasion resistance)
An aqueous solution containing a lotion was dropped onto the coating film, and a load of 4.5Kg was applied to Scotch-Brite (3M Co., ltd.: model 7447C) to make it slide back and forth. Every 500 times the sliding is stopped, the exposure state of the substrate is observed, and the number of times the substrate is observed and checked.
Examples 2 to 12 and comparative examples 1 to 5
A coating composition was obtained in the same manner as in example 1, except that the components shown in table 3 were mixed in the proportions shown in table 3. The properties of the obtained coating composition were examined in the same manner as in example 1. The results are shown in Table 3.
Nonionic surfactant B in table 3 represents polyoxyethylene tridecyl ether.
Example 13
The following components were mixed in the order described.
(A) 26.3 parts of the PTFE aqueous dispersion A obtained in production example 1
(B) 2.6 parts of FEP aqueous dispersion (solid content: 62.0% by mass)
(C) PAI (solid matter) 11.8 parts
(D) 2.1 parts of carbon black
(E) Nonionic surfactant A (polyoxyethylene tridecyl ether, dispanol TOC (50% aqueous solution) manufactured by Nikko Co., ltd.) 2.0 parts
(F) 13.0 parts of organic solvent (N-methyl-2-pyrrolidone)
(G) Amine (Ammonia) 0.1 part
(H) 0.2 part of thickener (methylcellulose)
(I) 41.9 parts of water
(J) 2.6 parts of filling material (SiC, new Mohs hardness 13)
The properties of the obtained coating composition were examined in the same manner as in example 1. The results are shown in Table 4.
Examples 14 to 21 and comparative examples 6 to 7
A coating composition was obtained in the same manner as in example 13, except that the components shown in table 4 were mixed in the proportions shown in table 4. The properties of the obtained coating composition were examined in the same manner as in example 13. The results are shown in Table 4.
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Claims (15)

1. A coating composition comprising a fluoroethylene-based polymer, a filler material and water, wherein,
The content of the fluorine-containing ethylenic polymer is 1 to 50% by mass relative to the coating composition,
the filler is at least one selected from the group consisting of:
(i) 0.1 to 80 mass% of a filler having a new mohs hardness of 9 or more relative to the fluoroethylene-based polymer;
(ii) 0.1 to 120 mass% of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluoroethylene-based polymer; and
(iii) 1 to 150 mass% of a filler material having a new mohs hardness of less than 5 relative to the fluoroethylene-based polymer.
2. The coating composition of claim 1, wherein the filler material is at least one selected from the group consisting of:
(i-1) 0.1 to 15 mass% of a filler having a new mohs hardness of 9 or more relative to the fluorine-containing ethylenic polymer; and
(ii-1) 0.1 to 20% by mass of a filler having a new mohs hardness of 5 or more and less than 9 relative to the fluorine-containing ethylenic polymer.
3. The coating composition of claim 2, wherein the coating composition does not comprise a heat resistant resin that does not include the fluoroethylene-based polymer therein.
4. A coating composition according to claim 2 or 3, wherein the content of the fluorine-containing ethylenic polymer is 15 mass% or more with respect to the coating composition.
5. The coating composition according to any one of claims 2 to 4, wherein the content of the fluorine-containing ethylenic polymer is 49 mass% or less with respect to the coating composition.
6. The coating composition according to any one of claims 2 to 5, wherein the viscosity of the coating composition is 10 mPa-s or more and 1000 mPa-s or less at 25 ℃.
7. The coating composition of claim 1, wherein the coating composition comprises a heat resistant resin that excludes the fluoroethylene-based polymer.
8. The coating composition according to claim 7, wherein the content of the fluorine-containing ethylenic polymer is 1 to 30% by mass relative to the coating composition.
9. The coating composition according to claim 7 or 8, wherein the viscosity of the coating composition is 50 mPa-s or more and 1500 mPa-s or less at 25 ℃.
10. The coating composition of any one of claims 1-9, wherein the fluoroethylene-based polymer comprises polytetrafluoroethylene.
11. The coating composition according to claim 9 or 10, wherein the polytetrafluoroethylene content is 50 mass% or more with respect to the fluorine-containing ethylenic polymer.
12. The coating composition according to any one of claims 1 to 11, wherein the gelation time of the coating composition in the stirring stability test is 4 hours or more.
13. The coating composition according to any one of claims 1 to 12, wherein the number of applications of the coating composition in a continuous spray coatability test until white spots are generated is 100 or more.
14. A coating formed from the coating composition of any one of claims 1-13.
15. A laminated coating comprising the coating of claim 14.
CN202210234615.5A 2022-03-09 2022-03-09 Coating composition, coating film, laminated coating film, and coated article Pending CN116769364A (en)

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