WO2023120540A1 - Composition de revêtement par électrodéposition cationique, produit revêtu par électrodéposition et procédé de production d'un produit revêtu par électrodéposition - Google Patents

Composition de revêtement par électrodéposition cationique, produit revêtu par électrodéposition et procédé de production d'un produit revêtu par électrodéposition Download PDF

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WO2023120540A1
WO2023120540A1 PCT/JP2022/046966 JP2022046966W WO2023120540A1 WO 2023120540 A1 WO2023120540 A1 WO 2023120540A1 JP 2022046966 W JP2022046966 W JP 2022046966W WO 2023120540 A1 WO2023120540 A1 WO 2023120540A1
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electrodeposition coating
coating composition
coated
compound
cationic electrodeposition
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PCT/JP2022/046966
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English (en)
Japanese (ja)
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雄大 山下
シャラフ，マハ
沙理 中島
祐斗 岩橋
俊雄 印部
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日本ペイント・オートモーティブコーティングス株式会社
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Priority to JP2023536560A priority Critical patent/JP7429332B2/ja
Publication of WO2023120540A1 publication Critical patent/WO2023120540A1/fr

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    • 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
    • C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
    • 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
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • 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
    • C09D179/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen, with or without oxygen, or carbon only, not provided for in groups C09D161/00 - C09D177/00
    • C09D179/02—Polyamines
    • 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
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • 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

Definitions

  • the present invention relates to a cationic electrodeposition coating composition, an electrodeposition coating, and a method for producing an electrodeposition coating.
  • Cationic electrodeposition paints are often used as undercoat paints to impart rust resistance to industrial products such as automobiles. From the viewpoint of rust prevention, it is required that the coating film be uniformly formed on the object to be coated. However, it is difficult to cover the edges with a sufficiently thick coating, and corrosion is likely to occur. Therefore, it has been proposed to increase the viscosity of the paint.
  • US Pat. No. 6,200,000 teaches the addition of polyvinylformamide polymer to cationic electrodeposition paints.
  • Patent Document 2 teaches adding a polyvinyl compound to a cationic electrodeposition paint.
  • an aminated epoxy resin (A); a blocked isocyanate curing agent (B); a pigment (C); A polyamidine compound or a hydrophobized modified product thereof (D),
  • the polyamidine compound or its hydrophobized modified product (D) has the following general formula (I):
  • R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.
  • a cationic electrodeposition coating composition having a structural unit represented by [2]
  • the hydrophobized modified form of the polyamidine compound has a cyclic structural unit derived from an unsaturated nitrile or the following general formula (X):
  • R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and R 3 is a substituted or unsubstituted linear or branched chain having
  • cationic electrodeposition coating composition [4] The cationic electrodeposition coating composition according to [1] or [2], wherein the polyamidine compound or its hydrophobized modified product (D) has a weight average molecular weight of 50,000 or more.
  • the aminated epoxy resin (A) is an aminated epoxy resin obtained by reacting an amine compound with an epoxy resin, the amine compound is a combination of two types of primary amine and secondary amine;
  • the primary amine has the formula: NH 2 —(CH 2 )n—NR 11 R 12 (In the formula, R 11 and R 12 are the same or different and represent an alkyl group having 1 to 6 carbon atoms which may have a terminal hydroxyl group, and n represents an integer of 2 to 4.) has wherein said secondary amine has the formula: R13R14NH _ (In the formula, R 13 and R 14 are the same or different and represent an alkyl group having 1 to 4 carbon atoms and having a terminal hydroxyl group.) or the amine compound comprises one or more selected from the group consisting of ketimine compounds and diketimine compounds, The cationic electrodeposition coating composition according to [1] or [2].
  • an object to be coated An electrodeposition-coated article having, on the article to be coated, an electrodeposition coating film formed from the cationic electrodeposition coating composition according to [1] or [2].
  • a voltage is applied between the article to be coated and the counter electrode, and the uncured electrodeposition is applied to the article to be coated.
  • a step of applying an electrodeposition pretreatment agent to the object to be coated The article to be coated to which the pretreatment agent for electrodeposition has been applied is immersed in the cationic electrodeposition coating composition, and then a voltage is applied between the article to be coated and a counter electrode to remove the uncoated material from the article to be coated.
  • a step of forming a cured electrodeposition coating a step of heating the uncured electrodeposition coating film at a temperature of 75° C. or more and 200° C.
  • the cationic electrodeposition coating composition contains an aminated epoxy resin (A), a blocked isocyanate curing agent (B), a pigment (C), and a polyamidine compound or a hydrophobized modified product thereof (D),
  • the polyamidine compound or its hydrophobized modified product (D) has the following general formula: (In the formula, R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.)
  • a cationic electrodeposition paint composition it is possible to provide a cationic electrodeposition paint composition, an electrodeposition-coated article, and a method for producing the same that provide a coating film with excellent rust resistance, particularly edge rust resistance, and appearance.
  • the polymer viscosity agent interacts with the film-forming resin and pigment to increase the viscosity of the cationic electrodeposition paint composition.
  • the coating composition is suppressed from flowing during heating. However, it is difficult to cure the coating composition while covering the edges.
  • a polyamidine compound having a cyclic amidine skeleton (hereinafter referred to as a cyclic polyamidine compound) is added to the coating composition.
  • a cyclic polyamidine compound has an electric charge.
  • a charged polyamidine compound tends to deposit on the edge portion.
  • the coating composition can be cured while covering the edges, thereby improving the rust prevention of the edges.
  • a cyclic polyamidine compound may be modified to introduce a hydrophobic group from the viewpoint of paint stability.
  • a product into which a hydrophobic group has been introduced is referred to herein as a "hydrophobic modified product".
  • the coating film-forming resin flows to some extent when heated, the surface of the resulting cured coating film is leveled and a good appearance can be obtained.
  • the cationic electrodeposition coating composition according to the present embodiment (hereinafter sometimes simply referred to as coating composition) comprises an aminated epoxy resin (A), a blocked isocyanate curing agent (B), and a pigment (C). , and a polyamidine compound or a hydrophobized modified product thereof (D).
  • the polyamidine compound or its hydrophobized modified product (D) has the following general formula: (In the formula, R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.) It has a structural unit represented by
  • the aminated epoxy resin (A) is a film-forming resin.
  • the aminated epoxy resin is included in the coating composition in the form of a resin emulsion along with the blocked polyisocyanate curing agent.
  • at least one oxirane ring (also referred to as "epoxy group") of the epoxy resin is aminated.
  • the number average molecular weight of the aminated epoxy resin (A) is, for example, 1,000 or more and 7,000 or less. When the number average molecular weight is 1,000 or more, the resulting cured electrodeposition coating film is likely to have improved rust resistance and solvent resistance. When the number average molecular weight is 7,000 or less, the viscosity of the aminated epoxy resin (A) can be easily adjusted, smooth synthesis becomes possible, and the resulting aminated epoxy resin (A) can be emulsified and dispersed. becomes easier.
  • the aminated epoxy resin (A) may have a number average molecular weight of 1,500 or more and 4,000 or less.
  • the number average molecular weight of the aminated epoxy resin (A) is a styrene homopolymer conversion value measured using gel permeation chromatography.
  • the amine value of the aminated epoxy resin (A) is, for example, 20 mgKOH/g or more and 100 mgKOH/g or less.
  • the amine value of the aminated epoxy resin (A) is 20 mgKOH/g or more, the emulsified dispersion stability of the aminated epoxy resin (A) in the coating composition is improved.
  • the amine value is 100 mgKOH/g or less, the amount of amino groups in the cured electrodeposition coating film is appropriate, and the decrease in water resistance of the coating film is suppressed.
  • the amine value of the aminated epoxy resin (A) may be 20 mgKOH/g or more and 80 mgKOH/g or less.
  • the amine value can be determined by the following method according to ASTM D2073. (1) Accurately weigh 500 mg of aminated epoxy resin into a 200 ml Erlenmeyer flask. (2) Add about 50 ml of glacial acetic acid and dissolve uniformly. (3) Add 5 to 6 drops of indicator (methyl violet solution) and stir evenly. (4) Titration is continued with 0.1N perchloric acid acetic acid solution, and the end point is the bright green point. ((3) and (4) above may be replaced by potentiometric titration.)
  • the hydroxyl value of the aminated epoxy resin (A) is, for example, 150 mgKOH/g or more and 650 mgKOH/g or less.
  • the hydroxyl value of the aminated epoxy resin may be 150 mgKOH/g or more and 400 mgKOH/g or less.
  • the hydroxyl value can be determined by the neutralization titration method using an aqueous potassium hydroxide solution described in JIS K 0070.
  • the aminated epoxy resin (A) has a number average molecular weight within the range of 1,000 to 7,000, an amine value of 20 to 100 mgKOH/g, and a hydroxyl value of 150 to 650 mgKOH/g (preferably is 150 to 400 mgKOH/g), the rust prevention property of the object to be coated is likely to be further improved.
  • the coating composition may contain a plurality of aminated epoxy resins (A) with different amine values and/or hydroxyl values.
  • the average amine value and the average hydroxyl value calculated based on the mass ratio of the plural aminated epoxy resins (A) fall within the above ranges.
  • the plural aminated epoxy resins (A) are composed of an aminated epoxy resin having an amine value of 20 to 50 mgKOH/g and a hydroxyl value of 50 to 300 mgKOH/g and an amine value of 50 to 200 mgKOH/g. and an aminated epoxy resin having a hydroxyl value of 200 to 500 mgKOH/g.
  • the aminated epoxy resin (A) can be prepared, for example, by reacting the oxirane ring of the epoxy resin with an amine compound.
  • an amine compound that is generally used for producing an aminated epoxy resin is used.
  • commonly used amine compounds include primary amines such as butylamine, octylamine, monoethanolamine; secondary amines such as diethylamine, dibutylamine, methylbutylamine, diethanolamine, N-methylethanolamine; complex amines such as diethylenetriamine; Amines are mentioned.
  • the above primary amine can control the reaction by forming a ketimine group using a ketone compound and by so-called blocking.
  • Ketimine-forming ketone compounds include methyl isopropyl ketone (MIPK), diisobutyl ketone (DIBK), methyl isobutyl ketone (MIBK), diethyl ketone (DEK), ethyl butyl ketone (EBK), ethyl propyl ketone (EPK), di Examples include propyl ketone (DPK) and methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK) is preferably used.
  • MIPK isopropyl ketone
  • DIBK diisobutyl ketone
  • MIBK methyl isobutyl ketone
  • DEK diethyl ketone
  • EBK ethyl butyl ketone
  • EPK ethyl propyl ketone
  • di Examples include propyl ketone (DPK) and methyl ethyl ketone (
  • a tertiary amine may be used, and specific examples thereof include triethylamine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, and the like. These amines may be used individually by 1 type, and may use 2 or more types together.
  • the amine compound is preferably used in an amount of 0.9 equivalent or more and 1.2 equivalent or less with respect to 1 equivalent of the epoxy group of the raw material epoxy resin.
  • the reaction conditions for amination can be appropriately selected according to the reaction scale and the like. For example, the reaction may be carried out at 80° C. to 150° C. for 0.1 hour to 5 hours, or at 120° C. to 150° C. for 0.5 hours to 3 hours.
  • primary amino groups, secondary amino groups and tertiary amino groups other than ketimine are used as amine compounds that modify the oxirane ring (also referred to as "epoxy group") of the epoxy resin.
  • amine compounds that modify the oxirane ring also referred to as "epoxy group”
  • the amine compound is a combination of two types of primary amine and secondary amine, and the primary amine has the formula: NH 2 —(CH 2 )n—NR 11 R 12 (1)
  • R 11 and R 12 are the same or different and represent an alkyl group having 1 to 6 carbon atoms which may have a terminal hydroxyl group, and n represents an integer of 2 to 4.
  • R13R14NH 2
  • R 13 and R 14 represent an alkyl group having 1 to 4 carbon atoms and having a terminal hydroxyl group.
  • a tertiary amino group or a tertiary amino group produced by the reaction of a secondary amino group present in the primary amine may also react with an epoxy group to form a quaternary ammonium group, but this reaction is thought to be rare. be done.
  • the primary amine has the above formula (1), and R 11 and R 12 are specifically methyl, ethyl, propyl or butyl, and may have a terminal hydroxyl group. Further, n is 2 to 4, preferably 3. Specific examples of primary amines include aminopropyldiethanolamine, dimethylaminopropanediamine, diethylaminopropanediamine, dibutylaminopropanediamine and the like.
  • the above secondary amine is a secondary amine having the above formula (2), and is obtained by bonding R 13 and R 14 to a nitrogen atom, and R 3 and R 4 both have hydroxyl groups and have 1 to 1 carbon atoms. It has 4 alkyl groups. Specific examples of secondary amines include dimethanolamine and diethanolamine.
  • the amine compound used for amination may contain an amine compound having a ketimine group or a diketimine group.
  • the coating composition may optionally contain aminated resins other than the aminated epoxy resin (A), such as aminated acrylic resins and aminated polyester resins.
  • the coating composition may also contain other film-forming resins other than the aminated resins described above. Examples of other coating film-forming resins include hydroxyl group-containing acrylic resins, hydroxyl group-containing polyester resins, urethane resins, butadiene resins, phenol resins, and xylene resins.
  • 80% by mass or more, further 90% by mass or more, particularly 100% by mass may be the aminated epoxy resin (A).
  • the blocked polyisocyanate curing agent (B) (hereinafter sometimes simply referred to as curing agent (B)) also constitutes the electrodeposition coating film.
  • the blocked polyisocyanate curing agent (B) preferentially reacts with the amine groups of the aminated epoxy resin (A) and further reacts with hydroxyl groups to cure the aminated epoxy resin (A).
  • a blocked isocyanate curing agent (B) can be prepared by blocking a polyisocyanate with a blocking agent.
  • polyisocyanates examples include aliphatic diisocyanates such as hexamethylene diisocyanate (including trimers), tetramethylene diisocyanate and trimethylhexamethylene diisocyanate; Aromatic diisocyanates such as polyisocyanate, 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate and xylylene diisocyanate can be mentioned.
  • sealants include monohydric alkyl (or aromatic) alcohols such as n-butanol, n-hexyl alcohol, 2-ethylhexanol, lauryl alcohol, phenol carbinol, methylphenyl carbinol; cellosolves such as hexyl ether and ethylene glycol mono-2-ethylhexyl ether; polyether type double-ended diols such as polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol phenol; ethylene glycol, propylene glycol, 1,4-butanediol and the like and polyester type double-ended polyols obtained from dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, suberic acid and sebacic acid; phenols such as para-t-butylphenol and cresol; dimethyl ketoxime and methyl ethyl keto Oximes such as oxime, methyl iso
  • the blocking rate of the blocked isocyanate curing agent (B) is preferably 100%. This improves the storage stability of the coating composition.
  • the content of the curing agent (typically curing agent (B)) is set in consideration of the amount, structure, etc. of the coating film-forming resin (typically aminated epoxy resin (A)). Specifically, a curing agent is used in an amount sufficient to react with active hydrogen-containing functional groups such as primary amino groups, secondary amino groups and hydroxyl groups possessed by the film-forming resin.
  • the solid content mass ratio of the coating film-forming resin to the curing agent (coating film-forming resin/curing agent) is 90/10 to 50/50, more preferably 80/20 to 65/35. are blended as The solids weight ratio of film-forming resin to curing agent controls the flowability and cure rate of the coating composition.
  • the coating composition may contain a curing agent other than the blocked isocyanate curing agent (B), if necessary.
  • Other curing agents include, for example, organic curing agents such as melamine resins or phenolic resins, silane coupling agents, and metal curing agents. Of all the curing agents contained in the coating composition, 80% by mass or more, further 90% by mass or more, particularly 100% by mass may be the blocked isocyanate curing agent (B).
  • Pigments are pigments commonly used in paint compositions.
  • pigments include coloring pigments such as titanium white (titanium dioxide), carbon black and red iron oxide; extender pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica and clay; iron phosphate, aluminum phosphate, calcium phosphate , aluminum tripolyphosphate, and antirust pigments such as aluminum phosphomolybdate and aluminum zinc phosphomolybdate.
  • the coating composition may contain an extender pigment in that the edge rust prevention property can be further improved. Extender pigments can moderately interact with cyclic polyamidine compounds.
  • the solid content of the coating composition means all the components contained in the coating composition that remain solid even after the solvent is removed.
  • the solid content of the coating composition specifically includes the aminated epoxy resin (A), the blocked polyisocyanate curing agent (B), the pigment (C) and the cyclic polyamidine compound or its They are a hydrophobized modified product (D) and a solid component such as a pigment dispersing resin that is optionally included.
  • Pigments are usually added to the paint composition as a pigment dispersion paste containing a pigment dispersion resin and a pigment.
  • a pigment dispersing resin is a resin for dispersing a pigment.
  • Pigment dispersing resins include, for example, pigment dispersing resins having cationic groups, such as modified epoxy resins having at least one selected from quaternary ammonium groups, tertiary sulfonium groups and primary amino groups.
  • Specific examples of pigment dispersion resins include quaternary ammonium group-containing epoxy resins and tertiary sulfonium group-containing epoxy resins.
  • the aqueous solvent include ion-exchanged water and ion-exchanged water containing a small amount of alcohol.
  • a cyclic polyamidine compound or a hydrophobized modified product thereof (D) has the following general formula: (In the formula, R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.) It has a structural unit represented by
  • a polyamidine compound having such a cyclic structure has an electric charge, so it is likely to precipitate at the edge, and further increases the viscosity of the coating composition. Therefore, it is considered that the edge rust prevention property is improved.
  • R 1 and R 2 may each independently be a hydrogen atom.
  • X represents an anion, for example a halogen ion.
  • Halogen ions include F ⁇ , Cl ⁇ , Br ⁇ and I ⁇ .
  • the halogen ion may be Cl 2 ⁇ because it is easily available.
  • the cyclic polyamidine compound (D) can be synthesized, for example, by hydrolyzing a copolymer of N-vinylcarboxylic acid amide and unsaturated nitrile in the presence of an acid. During hydrolysis in the presence of an acid, the amide group derived from the N-vinylcarboxylic acid amide hydrolyzes and reacts with the cyano group of the unsaturated nitrile to form a cyclic amidine skeleton.
  • N-vinylcarboxylic acid amides include N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylformamide, N-methyl-N-vinylformamide, N-vinylpropionamide and N-vinylbutyric acid. Amides can be mentioned. These are used singly or in combination of two or more.
  • the unsaturated nitrile may have, for example, 3 to 18 carbon atoms, or 3 to 9 carbon atoms.
  • Specific examples of unsaturated nitriles include acrylonitrile; ⁇ -alkylacrylonitrile such as methacrylonitrile and ethacrylonitrile; fumaronitrile; ⁇ -halogenoacrylonitrile such as ⁇ -chloroacrylonitrile and ⁇ -bromoacrylonitrile. These are used singly or in combination of two or more.
  • the acid used for hydrolysis is, for example, a strong inorganic acid, specifically hydrochloric acid, nitric acid and p-toluenesulfonic acid.
  • the cyclic polyamidine compound (D) may be a partially hydrolyzed copolymer of N-vinylcarboxylic acid amide and unsaturated nitrile. Using a chemical formula, it can be explained as follows.
  • an N-vinylcarboxylic acid amide is represented by CH 2 ⁇ CR 4 --NH--CO--R 6 and an unsaturated nitrile is represented by CH 2 ⁇ CR 5 --CN
  • their copolymerized polymer has the following general formula: commonly represented as (II).
  • R 1 and R 2 are used in general formula (I)
  • R 4 to R 6 are used because general formula (I) and general formula (II) are different parts of the copolymer.
  • R 4 , R 5 and R 6 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.
  • the copolymer of (II) in this general formula represents a state in which each monomer is alternately polymerized, but in fact, the structural unit (III) from the following N-vinylcarboxylic acid amide and the unsaturated nitrile Structural unit (IV) and are composed of randomly combined: (In formulas (III) and (IV) above, R 4 to R 6 have the same meanings as above.)
  • the ratio of the number of structural units (I) to the total number of the structural units (I) and the structural units (II) in one molecule of the cyclic polyamidine compound (D): I/(I+II) is 5% or more. Well, it may be 10% or more, and it may be 20% or more. The ratio: I/(I+II) may be 100%, may be 90% or less, or may be 80% or less.
  • Another preferred embodiment of the present invention is to modify the cyclic polyamidine compound to introduce a hydrophobic portion into the polyamidine compound.
  • Hydrophobization has the advantage of improving the stability of the coating when forming the coating (cationic electrodeposition coating composition). More specifically, by hydrophobizing the polyamidine compound, it is possible to improve the storage stability when the resin emulsion containing the aminated epoxy resin (A) and the curing agent is mixed with the polyamidine compound.
  • Hydrophobic modification is mainly performed by the following two methods. In the first hydrophobizing modification method, when the unsaturated nitrile structural units (IV) are arranged next to each other, a cyclization reaction between the nitrile groups with an acid occurs to generate a cyclized structural unit.
  • the chemical reaction formula for the formation of the nitrile cyclization structural unit is believed to be:
  • two nitrile groups (CN) are cyclized to form the nitrogen atom-containing 6-membered ring structure (aminopyridine structure or 6-membered ring pyridine derivative-like structure) as described above. Since the nitrile cyclized structural unit is more hydrophobic than other moieties, it can be hydrophobized.
  • the reaction is carried out by heating in the presence of an acid.
  • Acids are, for example, weak acids such as acetic acid, formic acid, lactic acid, phosphoric acid, oxalic acid, and hydrogen sulfide, and the heating conditions are preferably 70 to 98°C.
  • the amount of acid added is preferably 5 to 40 parts by mass, more preferably 8 to 25 parts by mass, per 100 parts by mass of the polyamidine compound.
  • the reaction time can be appropriately selected according to the heating conditions and the amount of acid added, and can be selected, for example, in the range of 12 to 80 hours, more preferably 36 to 72 hours.
  • pressurization conditions may be added in order to accelerate the reaction.
  • the second method of hydrophobization modification is a method of reacting the amidine ring represented by the above formula (I) with a halogenated alkyl compound to bond the alkyl group to the amidine ring to impart hydrophobicity.
  • a reaction equation is as follows: (In the reaction formula above, R 1 to R 3 and X have the same meanings as above, and Hal represents a halogen atom.)
  • the reaction is carried out by heating in the presence of an alkali.
  • the reaction conditions include a mode in which an alkaline substance such as sodium hydroxide, potassium hydroxide, or aqueous ammonia is added under conditions of pH 4.0 to 6.5.
  • the heating conditions are preferably 80°C to 98°C.
  • the reaction time can be appropriately selected according to the heating conditions, pH conditions and the type of alkaline substance used, and can be selected, for example, in the range of 2 to 36 hours, more preferably 10 to 24 hours.
  • pressurization conditions may be added.
  • R 3 is a substituted or unsubstituted linear or branched C 3-12 alkyl group or a substituted or unsubstituted C 6-12 aromatic at least any of the groups.
  • R 3 is an alkyl group (e.g., n-propyl group, sec-propyl group, n-butyl group, sec-butyl group, hexyl group, n-pentyl group, sec-pentyl group, neopentyl group , heptyl group, pentyl group, octyl group, etc.); or aromatic groups (eg, benzyl group, naphthalene group, etc.).
  • substituents for these groups substituents that do not affect hydrophobization modification can be used without particular limitation. Examples of substituents include alkenyl groups having 3 to 6 carbon atoms and alkyl ether groups having 3 to 6 carbon atoms.
  • the above alkyl group and aromatic group preferably have no substituents.
  • the halogen atom in the halogenated alkyl includes a chlorine atom, a bromine atom and a fluorine atom.
  • Alkyl halides (R 3 -Hal) are more particularly chlorohexane, bromohexane, chloropentane, bromopentane, iodohexane, iodopentane, chloroheptane, bromoheptane, iodoheptane, chlorooctane, bromooctane, iodooctane etc.
  • the weight average molecular weight of the cyclic polyamidine compound or its hydrophobized modified product (D) is, for example, 50,000 or more. As a result, it is possible to obtain the effect of improving the edge portion rust prevention property with a small amount.
  • the weight average molecular weight of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 80,000 or more, 100,000 or more, or 300,000 or more.
  • the weight average molecular weight of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 4 million or less, 3.5 million or less, 3.2 million or less, or 3 million or less. In one aspect, the weight average molecular weight of the cyclic polyamidine compound or its hydrophobized modified product (D) is 50,000 or more and 4,000,000 or less, and may be 80,000 or more and 3,200,000 or less.
  • the weight-average molecular weight of the cyclic polyamidine compound or its hydrophobized modified product (D) is measured by a molecular weight measuring device (DLS-7000 manufactured by Otsuka Electronics Co., Ltd., etc.) using a static light scattering method.
  • the solid content mass of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 0.2 ppm or more of the solid content mass of the cationic electrodeposition coating composition.
  • the solid content mass of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 1,200 ppm or less. Even if the addition amount of the cyclic polyamidine compound or its hydrophobized modified product (D) is such a small amount, it is possible to obtain the effect of improving edge rust prevention.
  • the solid content mass of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 1 ppm or more, 2 ppm or more, or 50 ppm or more.
  • the solid content mass of the cyclic polyamidine compound or its hydrophobized modified product (D) may be 1,000 ppm or less, 700 ppm or less, or 200 ppm or less. In one aspect, the solid content mass of the cyclic polyamidine compound or its hydrophobized modified product (D) is 20 ppm or more and 1,200 ppm or less, may be 25 ppm or more and 1,000 ppm or less, may be 25 ppm or more and 700 ppm or less, It can be 50 ppm or more and 200 ppm or less.
  • the coating composition may contain a curing catalyst.
  • the curing catalyst is not particularly limited, and those known in the field of coatings can be used.
  • curing catalysts include organic tin compounds and bismuth compounds.
  • organotin compounds include dibutyltin oxide, dioctyltin oxide, dioctyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dibenzoate, and dioctyltin dibenzoate.
  • Bismuth compounds include bismuth oxide, bismuth hydroxide, bismuth subsalicylate, and bismuth subnitrate.
  • the content of the curing catalyst may be 0.5% by mass or less, or 0.25% by mass or less, of the solid content of the coating composition.
  • the coating composition may further contain a metal nitrite.
  • the nitrite metal salt can further improve the edge rust prevention.
  • the nitrite metal salt is preferably an alkali metal nitrite or an alkaline earth metal nitrite, more preferably an alkaline earth metal nitrite.
  • Nitrite metal salts include, for example, calcium nitrite, sodium nitrite, potassium nitrite, magnesium nitrite, strontium nitrite, barium nitrite, and zinc nitrite.
  • the content of the nitrite metal salt is, for example, 0.001% by mass or more and 0.2% by mass or less in terms of the metal element of the metal component with respect to the total mass of the coating film-forming resin and the curing agent.
  • the paint composition may optionally contain additives commonly used in the paint field, such as organic solvents, anti-drying agents, surfactants such as antifoaming agents, viscosity modifiers such as acrylic resin fine particles, Anti-repellent agents, inorganic rust inhibitors may be included.
  • organic solvents include ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoethylhexyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and propylene glycol monophenyl ether.
  • inorganic rust inhibitors include vanadium salts, copper, iron, manganese, magnesium and calcium salts.
  • auxiliary complexing agents buffering agents, smoothing agents, stress relaxation agents, brightening agents, semi-brightening agents, antioxidants, ultraviolet absorbers, and the like may be included depending on the purpose.
  • the coating composition comprises a resin emulsion containing a film-forming resin (typically an aminated epoxy resin (A)) and a curing agent (typically a blocked polyisocyanate curing agent (B)), a pigment (C ), and a cyclic polyamidine compound or a hydrophobized modified product thereof (D: hereinafter simply referred to as “cyclic polyamidine compound (D)”, “cyclic polyamidine or hydrophobized modified product thereof (D)” ) are mixed by a commonly used method.
  • a film-forming resin typically an aminated epoxy resin (A)
  • a curing agent typically a blocked polyisocyanate curing agent (B)
  • B blocked polyisocyanate curing agent
  • C a pigment
  • D cyclic polyamidine compound or a hydrophobized modified product thereof
  • the cyclic polyamidine compound or its hydrophobized modified product (D), other components and additives may be added to the resin emulsion, the pigment dispersion paste, or the combination of the resin emulsion and the pigment dispersion paste. It may be added during or after mixing.
  • a cyclic polyamidine compound or a hydrophobized modified product thereof (D) or the like is added thereto, for example, in the form of an aqueous solution.
  • the resin emulsion is prepared by dissolving each of the aminated epoxy resin (A) and further film-forming resins and the blocked polyisocyanate curing agent (B) and further curing agents in an organic solvent to form a solution. After preparation and mixing of these solutions, they can be prepared by neutralizing with a neutralizing acid.
  • neutralizing acids examples include organic acids such as methanesulfonic acid, sulfamic acid, lactic acid, dimethylolpropionic acid, formic acid, and acetic acid.
  • the neutralizing acid may be one or more selected from the group consisting of formic acid, acetic acid and lactic acid.
  • the solid content of the resin emulsion is, for example, 25% by mass or more and 50% by mass or less, and may be 35% by mass or more and 45% by mass or less, relative to the total amount of the resin emulsion.
  • the solid content of the resin emulsion means all the components contained in the resin emulsion that remain solid even after removal of the solvent.
  • the solid content of the resin emulsion is specifically the aminated epoxy resin (A), the blocked isocyanate curing agent (B), and other solid components added as necessary, which are contained in the resin emulsion.
  • the amount of the neutralizing acid used may be 10% or more and 100% or less, or 20% or more and 70% or less, as the equivalent ratio of the neutralizing acid to the amino group equivalents of the aminated epoxy resin.
  • the equivalent ratio of the neutralizing acid to the amino group equivalent of the aminated epoxy resin is referred to as the neutralization rate.
  • the neutralization rate is 10% or more, affinity for water is ensured, and water dispersibility is improved.
  • a pigment dispersion paste is prepared by mixing a pigment dispersion resin and a pigment.
  • the solid content mass of the pigment dispersion resin in the pigment dispersion paste is not particularly limited, and may be, for example, 20 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the pigment.
  • the solid content mass of the pigment dispersion paste is, for example, 40% by mass or more and 70% by mass or less, and may be 50% by mass or more and 60% by mass or less.
  • the solid content of the pigment-dispersed paste means all the components contained in the pigment-dispersed paste that remain solid even after the solvent is removed.
  • the solid content of the pigment dispersion paste is specifically the pigment dispersion resin, the pigment, and other solid components added as necessary, which are contained in the pigment dispersion paste.
  • An electrodeposition coating film is formed by subjecting an object to be coated to electrodeposition coating using the coating composition.
  • An electrodeposition-coated article having an electrodeposition coating film is obtained by immersing the article to be coated in the cationic electrodeposition coating composition according to the present embodiment, and then applying a voltage between the article to be coated and the counter electrode.
  • a method comprising a step of forming an uncured electrodeposition coating film on an object and a step of heating the coating film at a temperature of 75° C. or more and 200° C. or less to obtain a cured electrodeposition coating film (manufacturing method 1 ).
  • the cationic electrodeposition coating composition comprises an aminated epoxy resin (A), a blocked isocyanate curing agent (B), a pigment (C), a cyclic polyamidine compound or a hydrophobized modified product thereof (D), including.
  • the voltage is, for example, 50 V or more and 450 V or less.
  • the bath liquid temperature is, for example, 10° C. or higher and 45° C. or lower.
  • the voltage application time is not particularly limited, and is, for example, 2 minutes or more and 5 minutes or less.
  • the material of the object to be coated is not particularly limited as long as it is electrically conductive.
  • the shape of the object to be coated is also not particularly limited, and may be a flat plate shape or a complicated three-dimensional shape. Examples of objects to be coated include cold-rolled steel sheets, hot-rolled steel sheets, stainless steel, electrogalvanized steel sheets, hot-dip galvanized steel sheets, zinc-aluminum alloy plated steel sheets, zinc-iron alloy plated steel sheets, and zinc-magnesium alloy plated steel sheets.
  • the article to be coated may be surface-conditioned with a zinc-based, titanium-based, or manganese-based surface conditioner before the chemical conversion treatment. This makes the crystals of the zinc phosphate coating more dense.
  • the formed uncured electrodeposited coating is, if necessary, washed with water and then heated at a temperature of 75° C. or higher and 200° C. or lower. Thereby, a curing reaction occurs and a cured electrodeposition coating film is obtained.
  • the curing temperature may be 100° C. or higher, and may be 110° C. or higher.
  • the curing temperature may be, for example, 180° C. or lower, or 150° C. or lower.
  • the heating time is not particularly limited, and is, for example, 10 to 30 minutes.
  • the electrodeposition-coated article has an article to be coated and an electrodeposition coating film formed on the article from the above cationic electrodeposition coating composition.
  • the electrodeposition coating film is cured.
  • the electrodeposition-coated article is produced, for example, by the method described above.
  • the electrodeposition-coated article is excellent in rust prevention, especially edge rust prevention.
  • the electrodeposition coating also has a good appearance.
  • the film thickness of the electrodeposition coating film after curing may be 5 ⁇ m or more and 60 ⁇ m or less from the viewpoint of rust prevention.
  • the film thickness of the electrodeposition coating film after curing may be 10 ⁇ m or more.
  • the film thickness of the electrodeposition coating film after curing may be 25 ⁇ m or less.
  • Edge rust resistance is evaluated, for example, by a salt spray test (35°C x 72 hours) in accordance with JIS Z 2371 (2000), which is performed on a cured electrodeposition coating film with a thickness of 25 to 50 ⁇ m. After the salt spray test, if the number of rust generated on the edge of the object to be coated is less than 5/cm 2 , it can be evaluated that the edge rust prevention is excellent.
  • the cyclic polyamidine compound may be used as a pretreatment agent for electrodeposition coating (electrodeposition pretreatment agent). Since the electrodeposition pretreatment layer containing the cyclic polyamidine compound is also deposited on the edge portion, a coating film having excellent edge portion rust prevention properties can be obtained.
  • an electrodeposition-coated article having an electrodeposition coating film is produced by applying an electrodeposition pretreatment agent containing a cyclic polyamidine compound or a hydrophobized modified product thereof (D) to the article to be coated, and a step of immersing the object to be coated with the pretreatment agent for electrodeposition into the substrate, and then applying a voltage between the object to be coated and the counter electrode to form an uncured electrodeposition coating film on the object to be coated. and heating the uncured electrodeposition coating film at a temperature of 75° C. or more and 200° C. or less to obtain a cured electrodeposition coating film.
  • an electrodeposition pretreatment agent containing a cyclic polyamidine compound or a hydrophobized modified product thereof (D) to the article to be coated, and a step of immersing the object to be coated with the pretreatment agent for electrodeposition into the substrate, and then applying a voltage between the object to be coated and the counter electrode to form an uncured electrodeposition coating film on the object to be coated. and heating the uncured electrodeposition coating film
  • the cationic electrodeposition coating composition used in production method 2 contains an aminated epoxy resin (A), a blocked isocyanate curing agent (B), and a pigment (C).
  • the cyclic polyamidine compound or its hydrophobized modified product (D) is contained in the electrodeposition pretreatment agent and is applied to the article to be coated prior to the cationic electrodeposition coating composition.
  • a pretreatment agent is used in combination as a paint set.
  • Electrodeposition Pretreatment Agent containing a cyclic polyamidine compound or its hydrophobized modified product (D) is applied to the object to be coated.
  • the electrodeposition pretreatment agent is, for example, an aqueous solution of a cyclic polyamidine compound or its hydrophobized modified product (D).
  • the concentration of the cyclic polyamidine compound is, for example, 10% by mass.
  • the application method is not particularly limited, and the object to be coated may be immersed in the electrodeposition pretreatment agent, or the electrodeposition pretreatment agent may be applied to the object to be coated.
  • Application methods include a coating method and a spray method.
  • a voltage may be applied to the article to be coated.
  • the voltage is, for example, 50 V or more and 450 V or less.
  • the bath liquid temperature is, for example, 10° C. or higher and 45° C. or lower.
  • the voltage application time is not particularly limited, and is, for example, 2 minutes or more and 5 minutes or less.
  • the object to be coated may be subjected to the next step without voltage application.
  • Examples of the object to be coated include those similar to those in manufacturing method 1.
  • the electrodeposition pretreatment agent is applied after the surface conditioning treatment and chemical conversion treatment and before electrodeposition coating.
  • Curing of Electrodeposited Coating The formed uncured electrodeposited coating is optionally washed with water and heated at a temperature of 75° C. or higher and 200° C. or lower. Thereby, a curing reaction occurs and a cured electrodeposition coating film is obtained. Curing conditions may be the same as in production method 1.
  • the film thickness of the electrodeposition coating film after curing may be 5 ⁇ m or more and 60 ⁇ m or less from the viewpoint of rust prevention.
  • the film thickness of the electrodeposition coating film after curing may be 10 ⁇ m or more.
  • the film thickness of the electrodeposition coating film after curing may be 25 ⁇ m or less.
  • Electrodeposition coating 2 According to production method 2, an object to be coated, an electrodeposition pretreatment layer containing a cyclic polyamidine compound or a hydrophobized modified product thereof (D) formed on the object to be coated, an aminated epoxy resin (A), and blocked isocyanate curing and an electrodeposition coating film formed from the cationic electrodeposition coating composition containing the agent (B) and the pigment (C).
  • an electrodeposition coated article including an article to be coated and an electrodeposition coating film formed on the article to be coated is obtained.
  • the electrodeposition coating film is formed by a cationic electrodeposition coating composition containing an aminated epoxy resin (A), a blocked isocyanate curing agent (B) and a pigment (C), and further containing at least Some cyclic polyamidine compounds or hydrophobized modified products thereof (D) are included.
  • A aminated epoxy resin
  • B blocked isocyanate curing agent
  • C a pigment
  • D hydrophobized modified products thereof
  • Preparation Example 1 Preparation of pigment dispersion paste A In a sand grind mill, 1,200 parts of the pigment dispersion resin obtained in Production Example 3, 3 parts of carbon black, 620 parts of kaolin, 500 parts of titanium dioxide, 70 parts of bismuth oxide, deionized 1100 g of water was added and dispersed until the particle size became 10 ⁇ m or less to obtain a pigment-dispersed paste A (solid content: 50%).
  • Preparation Example 2 Preparation of Pigment Dispersion Paste B In a sand grind mill, 1,500 parts of the pigment dispersion resin obtained in Production Example 3, 18 parts of carbon black, 680 parts of kaolin, 590 parts of titanium dioxide, 90 parts of organic tin, deionized. 570 parts of water was added and dispersed until the particle size became 10 ⁇ m or less to obtain a pigment-dispersed paste B (solid content: 52%).
  • Example 1 (1) Preparation of Cationic Electrodeposition Coating Composition A1 In a stainless container, 1394 g of ion-exchanged water, 560 g of resin emulsion prepared as follows, and 41 g of pigment dispersion paste A were added. After that, it was aged at 40° C. for 16 hours.
  • the cyclic polyamidine compound (D1) has a structural unit of the following formula.
  • a cold-rolled steel sheet (JIS G3141, SPCC-SD) was prepared as an object to be coated.
  • This steel plate was degreased by immersing it in a surf cleaner EC90 (manufactured by Nippon Paint Surf Chemicals Co., Ltd.) at 50° C. for 2 minutes. Subsequently, it was immersed in Surfdyne EC3200 (a zirconium chemical conversion treatment agent manufactured by Nippon Paint Surf Chemicals Co., Ltd.) at 35° C. for 90 seconds. After that, it was washed with deionized water.
  • a surf cleaner EC90 manufactured by Nippon Paint Surf Chemicals Co., Ltd.
  • Surfdyne EC3200 a zirconium chemical conversion treatment agent manufactured by Nippon Paint Surf Chemicals Co., Ltd.
  • a necessary amount of 2-ethylhexyl glycol was added to the cationic electrodeposition coating composition A1 so that the film thickness of the electrodeposition coating film after curing was 20 ⁇ m.
  • voltage application was started. The voltage was applied under the condition that the voltage was increased for 30 seconds and maintained for 150 seconds after reaching 180V. As a result, an uncured electrodeposition coating film was deposited on the object to be coated. The resulting uncured electrodeposition coating film was cured by heating at 160° C. for 15 minutes to obtain an electrodeposition coating having a cured electrodeposition coating film of 20 ⁇ m in thickness.
  • Example 2 A cationic electrodeposition coating composition A2 was prepared in the same manner as in Example 1, except that the amount of the polyamidine compound (D1) added was 100 ppm, to produce an electrodeposition coating.
  • Example 3 In place of the polyamidine compound (D1), a cyclic polyamidine compound (D2) (Hymo Co., Ltd., Himolock PVAD, weight average molecular weight of 100,000, partial hydrolyzate of acrylonitrile/N-vinylformamide copolymer, constitution of structural unit (I)
  • the cyclic polyamidine compound (D2) has a structural unit of the following formula.
  • Example 4 A cationic electrodeposition coating composition A4 was prepared in the same manner as in Example 1, except that 1,000 ppm of the polyamidine compound (D2) was added, and an electrodeposition coating was produced.
  • Example 1 A cationic electrodeposition coating composition a1 was obtained in the same manner as in Example 1, except that the pigment dispersion paste B was used instead of the pigment dispersion paste A and the polyamidine compound (D1) was not added. An electrodeposition coating was produced.
  • the object to be coated is cut from a cold-rolled steel plate (JIS G3141, SPCC-SD) to a special blade for L type (LB10K: manufactured by Olfa Co., Ltd., length 100 mm, width 18 mm, thickness 0.5 mm ), a test piece having a cured electrodeposition coating film having a thickness of 20 ⁇ m was prepared in the same manner as described above, except that it was changed to ).
  • This test piece was subjected to a salt spray test (35° C. ⁇ 72 hours) according to JIS Z 2371 (2000), and the number of rust spots generated on the edges of the object to be coated was examined.
  • the edge portion of the object to be coated is a region extending from the apex of the blade to 5 mm in the direction of the main body of the blade, and is present on the front and rear surfaces of the blade.
  • the total area of the edge portion is 10 cm 2 where the length of the blade is 100 mm ⁇ the width of the area (5 mm ⁇ 2).
  • Comparative Example 1 is an example that does not contain the polyamidine compound additive of the present disclosure. In this example, it was confirmed that the edge rust resistance was inferior.
  • Comparative Examples 2 and 3 are examples containing compounds (polyvinylformamide, poly-N-vinylacetamide) known as additives for improving edge rust resistance. In this example, while the edge rust prevention property was improved, the surface roughness was remarkably increased, resulting in poor paint film appearance.
  • Example 5 Preparation of electrodeposition pretreatment agent A 100 ppm aqueous solution of the polyamidine compound (D1) was prepared.
  • Cationic electrodeposition coating composition B was prepared in the same manner as in Example 1, except that the polyamidine compound (D1) was not added.
  • Example 6 An electrodeposition coated article having a cured electrodeposition coating film having a thickness of 20 ⁇ m was obtained in the same manner as in Example 5, except that the electrodeposition pretreatment agent was applied to the steel sheet by electrodeposition as follows.
  • Example 4 After applying the electrodeposition pretreatment agent, a cured electrodeposition coating film was formed in the same manner as in Example 5, except that a 100 ppm aqueous solution of polyvinylformamide (weight average molecular weight: 3,000,000) was used as the electrodeposition pretreatment agent. Then, an electrodeposition-coated article was obtained.
  • a 100 ppm aqueous solution of polyvinylformamide weight average molecular weight: 3,000,000
  • Electrodeposition pretreatment was carried out in the same manner as in Example 5, except that a 100 ppm aqueous solution of poly-N-vinylacetamide (weight average molecular weight: 50,000) was used as the electrodeposition pretreatment agent. After applying the agent, a cured electrodeposition coating film was formed to obtain an electrodeposition coating.
  • a 100 ppm aqueous solution of poly-N-vinylacetamide weight average molecular weight: 50,000
  • Example 7 A cationic electrodeposition coating composition was prepared in the same manner as in Example 1, except that 2 ppm of the polyamidine compound (D1) was added, and an electrodeposition coating was produced.
  • Example 8 A cationic electrodeposition coating composition was prepared in the same manner as in Example 1, except that 10 ppm of the polyamidine compound (D1) was added, and an electrodeposition coating was produced.
  • Production Example 11-1 Production of aminated epoxy resin (A1) In a reaction vessel, 26 parts of butyl cellosolve, 940 parts of bisphenol A type epoxy resin (trade name DER-331J, manufactured by Dow Chemical Co.), 380 parts of bisphenol A, 58 parts of phenol, Two parts of dimethylbenzylamine were added and the internal temperature was maintained at 120°C. After reacting until the epoxy equivalent reached 1100 g/eq, the temperature inside the reactor was cooled to 110°C.
  • bisphenol A type epoxy resin trade name DER-331J, manufactured by Dow Chemical Co.
  • Production Example 13-1 Production of Resin Emulsion (1) 400 g (solid content) of aminated epoxy resin (A1) and 160 g (solid content) of blocked polyisocyanate curing agent (B) obtained in Production Example 2 were mixed. , ethylene glycol mono-2-ethylhexyl ether was added to 3% (15 g) of solids. Next, formic acid was added so as to give a neutralization rate of 40% for neutralization, and ion-exchanged water was added to slowly dilute to obtain a resin emulsion (1).
  • Production Example 13-2 Production of Resin Emulsion (2) 400 g (solid content) of aminated epoxy resin (A2) and 160 g (solid content) of blocked polyisocyanate curing agent (B) obtained in Production Example 2 were mixed. , ethylene glycol mono-2-ethylhexyl ether was added to 3% (15 g) of solids. Next, formic acid was added so as to give a neutralization rate of 40% for neutralization, and ion-exchanged water was added to slowly dilute to obtain a resin emulsion (2).
  • Production Example 15 Preparation of Pigment Dispersion Paste
  • 1,200 parts of the pigment dispersion resin obtained in Production Example 3 3 parts of carbon black, 620 parts of kaolin, 500 parts of titanium dioxide, 70 parts of bismuth oxide, and 1,100 parts of deionized water were added. and dispersed until the particle size became 10 ⁇ m or less to obtain a pigment-dispersed paste A (solid content: 50%).
  • additive A hydrophobicization of polyamidine compound by cyclization of nitrile group
  • proportion of structural unit (I) and structural unit (I+II): I/I+II 30 to 40%
  • 1 part and 499 parts of deionized water were added to the reaction vessel and stirred to prepare a 2% aqueous solution.
  • the temperature in the reaction vessel is maintained at 90 degrees, 1 part of 90% acetic acid, and 30 parts of the epoxy resin having the amine group prepared above as an amine catalyst are added and heated for 60 hours to obtain an unsaturated nitrile.
  • Additive A which is a polyamidine compound (a hydrophobized polyamidine compound) having a cyclization segment (two nitrile groups (CN) are cyclized) units, was obtained.
  • Production Example 16-3 Production of Additive C 33.6 parts of a liquid epoxy resin having an epoxy equivalent weight of 220 g/equivalent was placed in a reactor and heated to 50° C. with stirring. Stirred for 1 hour. In a separate vessel, 50 parts of methyl isobutyl ketone and 11.2 parts of isophorone diisocyanate were mixed and the mixture was heated to 70°C with stirring. Then, the reaction mixture of the above liquid epoxy resin and dialkylamine was added over 1.5 hours and stirred at 70 for 1 hour to react to obtain a cationizing agent. 99 parts of polyvinyl alcohol (Mowiol, manufactured by Kuraray Co., Ltd.) and 1 part of the cationizing agent were mixed to obtain a polyvinyl alcohol (PVA) intermediate.
  • PVA polyvinyl alcohol
  • a reactor equipped with an agitator, thermometer and condenser was prepared and 1000 parts of epoxidized polybutadiene having an oxirane oxygen content of 6.5% and a number average molecular weight of 1800, 377 parts of ethylene glycol monobutyl ether and 131 parts of methyl ethanolamine were prepared. It was kept at 170° C. for 6 hours while stirring in a nitrogen gas stream. Next, the mixture was cooled to 120°C, 81.4 parts of acrylic acid, 8.8 parts of hydroquinone and 27.1 parts of ethylene glycol monobutyl ether were added, maintained at 120°C for 4 hours, and the solid concentration was 75% per molecule. An acrylic-modified polybutadiene resin (e2) containing two ⁇ , ⁇ -ethylenically unsaturated groups was obtained.
  • e2 acrylic-modified polybutadiene resin
  • Example 11 Production of electrodeposition coating composition 1394 parts of ion-exchanged water, 560 parts of resin emulsion (2) prepared in Production Example 3-2, and 41 parts of pigment dispersion paste prepared in Production Example 5 were added to a stainless container. , followed by aging at 40° C. for 16 hours. Next, Additive A prepared in Production Example 16-1 was added in an amount such that the solid content was 10 ppm of the solid content mass of the cationic electrodeposition coating composition to prepare a cationic electrodeposition coating composition.
  • Examples 12-14 and Comparative Examples 11-14 A cationic electrodeposition coating composition was prepared in the same manner as in Example 11, except that the types of resin emulsion and/or additives were changed to those shown in Table 4 below.
  • Examples 11, 12 and 14 are examples using a cationic electrodeposition coating composition using a polyamidine compound hydrophobized by the general formula (X), and Example 13 is hydrophobized by cyclization of nitrile groups.
  • This is an example using a cationic electrodeposition coating composition using a polyamidine compound, and both are excellent in surface roughness Ra and edge rust prevention.
  • This hydrophobized modified polyamidine compound also aims at stabilizing the resin emulsion, and the stability to the resin emulsion was also evaluated, and Examples 11 to 14 were also excellent in stability.
  • Comparative Examples 11 to 14 are examples using additives C to F.
  • Additive C of Comparative Example 11 is an additive corresponding to the polyvinyl alcohol-encapsulating cationic microgel described in WO2022/189111.
  • Comparative Example 11 is an example in which the additive C was used as an edge protective agent in a cationic electrodeposition coating composition.
  • Additive D in Comparative Example 12 is an additive corresponding to the alkoxylated polyethyleneimine described in WO 2022/128359.
  • Comparative Example 12 is an example in which the additive D is used as an edge antirust agent in a cationic electrodeposition coating composition.
  • Additive E in Comparative Example 13 is a cationic microgel
  • Comparative Example 13 is an example in which Additive E (cationic microgel) is used as an edge portion rust inhibitor.
  • Additive F in Comparative Example 14 is a polyvinyl polyamide/polyamine copolymer
  • Comparative Example 14 is an example in which Additive F (polyvinyl polyamide/polyamine copolymer) is used as an edge rust inhibitor. None of Comparative Examples 11 to 14 could achieve both edge rust prevention and surface smoothness. In addition, many of them have poor stability in resin emulsions.
  • the cationic electrodeposition coating composition of the present invention it is possible to obtain a coating film that is excellent in rust resistance, especially edge rust resistance, and appearance. Therefore, the cationic electrodeposition coating composition of the present invention is suitable for coating objects having edges. In addition, the cationic electrodeposition coating composition of the present invention is excellent in coating stability.
  • an aminated epoxy resin A
  • a blocked isocyanate curing agent B
  • a pigment C
  • a polyamidine compound or a hydrophobized modified product thereof D
  • the polyamidine compound or its hydrophobized modified product (D) has the following general formula (I):
  • R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.
  • a cationic electrodeposition coating composition having a structural unit represented by [2]
  • the hydrophobized modified form of the polyamidine compound has a cyclic structural unit derived from an unsaturated nitrile or the following general formula (X):
  • R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and R 3 is a substituted or unsubstituted linear or branched chain having 3 to 3 carbon atom
  • cationic electrodeposition coating composition [4] The cationic electrodeposition coating composition according to any one of [1] to [3], wherein the polyamidine compound or its hydrophobized modified product (D) has a weight average molecular weight of 50,000 or more.
  • the aminated epoxy resin (A) is an aminated epoxy resin obtained by reacting an amine compound with an epoxy resin, the amine compound is a combination of two types of primary amine and secondary amine;
  • the primary amine has the formula: NH 2 —(CH 2 )n—NR 11 R 12 (In the formula, R 11 and R 12 are the same or different and represent an alkyl group having 1 to 6 carbon atoms which may have a terminal hydroxyl group, and n represents an integer of 2 to 4.) has wherein said secondary amine has the formula: R13R14NH _ (In the formula, R 13 and R 14 are the same or different and represent an alkyl group having 1 to 4 carbon atoms and having a terminal hydroxyl group.) or the amine compound comprises one or more selected from the group consisting of ketimine compounds and diketimine compounds, The cationic electrodeposition coating composition according to any one of [1] to [6].
  • an object to be coated An electrodeposition-coated article having, on the article to be coated, an electrodeposition coating film formed from the cationic electrodeposition coating composition according to any one of [1] to [7].
  • a voltage is applied between the article to be coated and the counter electrode to remove the untreated material from the article to be coated.
  • a step of forming a cured electrodeposition coating and heating the uncured electrodeposition coating at a temperature of 75° C. or more and 200° C. or less to obtain a cured electrodeposition coating.
  • a step of applying an electrodeposition pretreatment agent to the object to be coated The article to be coated to which the pretreatment agent for electrodeposition has been applied is immersed in the cationic electrodeposition coating composition, and then a voltage is applied between the article to be coated and a counter electrode to remove the uncoated material from the article to be coated.
  • a step of forming a cured electrodeposition coating a step of heating the uncured electrodeposition coating film at a temperature of 75° C. or more and 200° C.
  • the cationic electrodeposition coating composition contains an aminated epoxy resin (A), a blocked isocyanate curing agent (B), a pigment (C), and a polyamidine compound or a hydrophobized modified product thereof (D),
  • the polyamidine compound or its hydrophobized modified product (D) has the following general formula: (In the formula, R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and X is an anion.)

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  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
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Abstract

L'invention concerne une composition de revêtement par électrodéposition cationique qui donne un film de revêtement ayant une exceptionnelle résistance à la rouille, en particulier à la rouille de bord, et un aspect exceptionnel.　La présente invention porte sur une composition de revêtement par électrodéposition cationique qui comprend une résine époxy aminée (A), un agent de durcissement isocyanate bloqué (B), un pigment (C) et un composé polyamidine ou une forme modifiée hydrophobisée de ce dernier (D), le composé polyamidine ou sa forme modifiée hydrophobisée (D) ayant un motif structural représenté par la formule générale (dans la formule, R1 et R2 représentent chacun indépendamment un atome d'hydrogène ou un groupe hydrocarboné en C1-3, et X représente un anion).
PCT/JP2022/046966 2021-12-22 2022-12-20 Composition de revêtement par électrodéposition cationique, produit revêtu par électrodéposition et procédé de production d'un produit revêtu par électrodéposition WO2023120540A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000026530A (ja) * 1998-07-09 2000-01-25 Mitsubishi Chemicals Corp 環状アミジン構造を有する重合体、その製造法及び用途
JP2000026790A (ja) * 1998-07-09 2000-01-25 Mitsubishi Chemicals Corp コーティング用重合体組成物及びその製造法
JP2011524934A (ja) * 2008-06-19 2011-09-08 ビーエーエスエフ コーティングス ゲゼルシャフト ミット ベシュレンクテル ハフツング 電着組成物および方法
WO2020262549A1 (fr) * 2019-06-28 2020-12-30 関西ペイント株式会社 Composition de peinture par électrodéposition cationique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000026530A (ja) * 1998-07-09 2000-01-25 Mitsubishi Chemicals Corp 環状アミジン構造を有する重合体、その製造法及び用途
JP2000026790A (ja) * 1998-07-09 2000-01-25 Mitsubishi Chemicals Corp コーティング用重合体組成物及びその製造法
JP2011524934A (ja) * 2008-06-19 2011-09-08 ビーエーエスエフ コーティングス ゲゼルシャフト ミット ベシュレンクテル ハフツング 電着組成物および方法
WO2020262549A1 (fr) * 2019-06-28 2020-12-30 関西ペイント株式会社 Composition de peinture par électrodéposition cationique

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