JPH0741699A - Thermosetting powder coating composition - Google Patents

Abstract

PURPOSE:To obtain a thermosetting powder coating composition having excellent weather resistance, acid resistance and adhesivity and exhibiting water-repellency and slipperiness by compounding a specific fluororesin having crosslinkable reactive group with a curing agent, a wax, a compound having coupling group and an epoxy resin. CONSTITUTION:This thermosetting powder coating composition capable of forming a coating film by the baking at <=200 deg.C, having excellent weather resistance, acid resistance and adhesivity to metallic material and exhibiting water-repellency and slipperiness comparable to those of thermoplastic fluororesin is produced by compounding (A) 0.01-10 pts.wt. of a synthetic wax or natural wax and (B) 0.001-1.5 pts.wt. of a compound having coupling group and/or 0.01-5.0 pts.wt. of an epoxy resin to 100 pts.wt. of a resin composition composed of (C) 60-97wt.% of a fluororesin having a fluorine-content of >=10wt.% and a glass transition temperature of 35-120 deg.C and containing crosslinkable reactive group and (D) 3-40wt.% of a curing agent reactive with the crosslinkable reactive group of the fluororesin to form a crosslinking bond.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fluororesin powder coating having a crosslinkable reactive group, which is blended with a synthetic wax or a natural wax to improve the slipperiness and water repellency of the coating film. Compound having ring group and /
Alternatively, the present invention relates to a thermosetting powder composition having excellent adhesion to a material, particularly stainless steel, and excellent impact resistance without impairing the weather resistance of a coating film by blending an epoxy resin.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to use a thermoplastic fluororesin powder composed of tetrafluoroethylene resin,
It is used for non-adhesive applications such as frying pans and rice cookers by taking advantage of the low surface tension which is a characteristic of fluororesins (Japanese Patent Laid-Open No. 61-181567 and Japanese Patent Laid-Open No. 61-1).
No. 51571, JP-A-61-181572). However, when the resin is melted to form a coating film, a temperature of about 400 ° C. is required, and the adhesion to the material is poor. Therefore, a thermosetting fluororesin-based powder coating which has improved these drawbacks has been developed (JP-A-1-10367).
No. 0). This thermosetting powder coating can form a coating film under baking conditions of 200 ° C or less, and is superior in adhesion to materials other than stainless steel as compared with conventional tetrafluoroethylene resin, and also has weather resistance and acid resistance. It has been widely used due to its excellent properties. However, compared to conventional resin powders made of tetrafluoroethylene resin, the fluorine content is low, so the water repellency and the slipperiness of the coating film, which are the characteristics of the fluororesin, are extremely poor, and the adhesion to the material is sufficient. It has the drawback of not being. Therefore, when coating a material such as stainless steel, it was necessary to perform a color conversion coating treatment such as a chromic acid-based treatment or a primer such as an epoxy resin-based coating having excellent adhesion to the material. For this reason, when a chromic acid-based treatment agent is used when performing clear coating with a fluororesin-based powder coating, coloring due to the treatment agent may occur,
There is also a problem in wastewater treatment of chromic acid chemicals. In addition, when the primer is applied, there is a defect that the weather resistance of the primer coating film is inferior to that of the fluororesin coating film, and delamination with the top coating fluororesin coating film is likely to occur. It was difficult to apply the fluororesin-based powder coating that makes the best use of the clearness. Also, in the case of colored coating with a fluororesin powder coating, the coating process tends to be complicated because chromic acid coating treatment and primer application are required.

[0003]

DISCLOSURE OF THE INVENTION According to the present invention, a coating film can be formed under a baking condition of 200 ° C. or less, and is excellent in weather resistance, acid resistance, adhesion to metal materials including stainless steel, and thermoplasticity. An object of the present invention is to provide a thermosetting fluororesin-based powder coating composition having water repellency and slipperiness comparable to those of fluororesins.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies aimed at improving the above-mentioned drawbacks of the prior art, the present inventors have found that a specific fluororesin (a) and a curing agent (b) having a crosslinkable reactive group.
And a synthetic wax or natural wax (c), (d) a compound having a coupling group, and / or
Or by blending the epoxy resin in a specific ratio,
It was found that the water repellency and the slip property are remarkably improved without impairing the performance such as weather resistance, acid resistance and adhesion property, and the adhesion property to a metal material is also remarkably improved, and based on this finding, the present invention was completed. I arrived. That is, the present invention provides (a)
60-97% by weight of a fluororesin having a fluorine content of 10% by weight or more and a glass transition temperature of 35 to 120 ° C., (b) reacting with the crosslinking reaction group of the fluororesin. (C) with respect to 100 parts by weight of a resin composition consisting of 3 to 40% by weight of a curing agent capable of forming crosslinks by
0.01 to 10 parts by weight of synthetic wax or natural wax (d) 0.001 of a compound having a coupling group
~ 1.5 parts by weight and / or 0.01-5 epoxy resin.
The present invention provides a thermosetting powder coating composition containing 0 part by weight.

The present invention will be described in detail below. The present invention relates to a resin composition comprising a specific fluororesin (a) having a crosslinkable reactive group and a curing agent (b), a synthetic wax or a natural wax (c), and (d) a compound having a coupling group and / or By blending epoxy resin in a specific ratio, water repellency and slipperiness are significantly improved without impairing performance such as weather resistance, acid resistance, and adhesion, and adhesion to metal materials is significantly improved and impact resistance is improved. The synthetic wax or the natural wax (c) used in the composition of the present invention has a melting point of 50 to 280 ° C., preferably 50 to 260 ° C., and is of plant, animal or mineral origin. Natural waxes or synthetic waxes can be used. The wax used in the composition of the present invention has a melting point of 50 ° C.
If it is less than the above range, the powder coating material tends to adhere to each other when it is made into a powder coating material. On the other hand, if the melting point is higher than 280 ° C., the powder coating material does not melt at the time of forming the coating film, so that it becomes difficult to sufficiently impart water repellency and slipperiness to the coating film. Further, the synthetic wax or the natural wax preferably has a melting point that melts at the time of forming a coating film. Since the coating film forming temperature differs depending on the application, a material having a melting point lower by about 10 to 20 ° C. than the applied coating film forming temperature is particularly preferable. For example, those having a melting point of 160 to 170 ° C. are particularly preferable for use in baking at 180 ° C. The shapes of the synthetic wax and the natural wax used in the composition of the present invention may be solid lumps, flakes, or powders, as long as they can be uniformly dispersed and kneaded at the time of producing a powder coating, and have various shapes. Can be used. Examples of the natural wax used in the composition of the present invention include montan wax, carnauba wax, beeswax, slack wax, paraffin wax, ceresin, and Japanese wax. Examples of synthetic waxes include long-chain alcohols (having 16 to 36 carbon atoms) such as reaction products of cetyl alcohol, stearyl alcohol, ceryl alcohol or melysyl alcohol with acids such as myristic acid, palmitic acid or stearic acid, and stearic acid. Glycerides of fatty acids such as glycol ester or polyethylene glycol, glycol ester and synthetic beeswax, such as aliphatic amine wax and high molecular weight aliphatic amide, polyamide wax, fluorinated polyolefin obtained by reaction of hydrogenated castor oil and monoethanolamine Examples thereof include wax, fatty acid ester wax, and unsubstituted polyolefin wax. In addition, these waxes may be used alone or in combination of two or more. The blending amount of the synthetic wax and the natural wax used in the composition of the present invention is 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin composition including the fluororesin and the curing agent.
If it is less than 0.01 part by weight, the compounding effect is not obtained, and if it exceeds 10 parts by weight, the smoothness of the powder coating film is deteriorated and the adhesion to the article to be coated is lowered.

Examples of the coupling agent used as the component (d) of the composition of the present invention include, for example, the general formula YSiX _n R _3-n ... [1] [wherein R represents a hydrogen atom, a methyl group or an ethyl group. , X represents a methoxy group, an ethoxy group or a β-methoxyethoxy group, and n represents 1, 2 or 3. Y is a vinyl group; a (meth) acryloxyalkyl group such as a methacryloxymethyl group, an acryloxyethyl group or a methacryloxypropyl group; a β- (3,4-epoxycyclohexyl) ethyl group or a γ-glycidoxypropyl group. Such an epoxy group-substituted alkyl group; γ-aminopropyl group, N-
It represents an aminoalkyl group such as (2-aminoethyl) -γ-aminopropyl group and N-phenyl-γ-aminopropyl group; and a chlorine atom-substituted alkyl group such as chloromethyl group and γ-chloropropyl group. ] Examples of such compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinyltris (β).
-Methoxyethoxy) silane, γ- (meth) acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyl Examples thereof include trimethoxysilane and γ-aminopropyltriethoxysilane, and commercially available products can be used. Examples of the coupling agent other than the silane coupling agent include a titanium coupling agent having an alkoxy group, an aluminum coupling agent, a zirconium coupling agent, and the like. Examples of titanium coupling agents include isopropyl trioctanoyl titanate, isopropyl diisostearoyl cumylphenyl titanate, isopropyl distearoyl methacryloyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl diisostearoyl acryloyl titanate, isopropyl isostearoyl diacryloyl. Titanate, isopropyl (dioctyl phosphate) titanate, isopropyl tri-n-stearoyl titanate, isopropyl-4-aminobenzenesulfonyl di (dodecylbenzenesulfonyl) titanate, isopropyl tricumylphenyl titanate, isopropyl di (4-aminobenzoyl) isostearoyl titanate , Isopropyl tri (dioctyl Pyrophosphate) titanate, isopropyl tri (octylbutyl pyrophosphate) titanate, tetraisopropyl di (dilauryl phosphite) titanate, tetraoctyl di (ditridecyl phosphite) titanate, tetraisopropyl di (ditridecyl phosphite) titanate, tetra ( 2,2-diallyloxymethyl-1-butoxy) di (ditridecyl) phosphite titanate, diisostearoyloxyacetate titanate, isostearoyl methacryloyloxyacetate titanate, isostearoylacryloyloxyacetate titanate, di (dioctylphosphate) oxyacetate titanate, 4-aminobenzoylisostearoyloxyacetate titanate, di (dioctylpyrophohate Feto) oxy acetate titanate, di (octyl butyl pyrophosphate) oxyacetate titanate, diisostearoyl ethylene titanate, isostearoyl Irume Tactile Leroy Le ethylene titanate, di (dioctyl phosphate) ethylene titanate, 4-
Examples thereof include aminobenzoylisostearoylethylene titanate, di (dioctylpyrophosphate) ethylene titanate, isopropyldimethacryloylisostearoyl titanate, isopropyltriisostearoyl titanate, and tetraisopropoxytitanium, and commercially available products can be used. Examples of the aluminum-based coupling agent include aluminum isopropoxide and acetoalkoxy aluminum diisopropylate, and commercially available products can be used. The zirconium-based coupling agent, for example, isopropyl trioctanoyl zirconate, isopropyl diisostearoyl cumylphenyl zirconate, isopropyl distearoyl methacryloyl zirconate, isopropyl tridodecylbenzenesulfonyl zirconate, isopropyl diisostearoyl acryloyl zirconate, Isopropyl isostearoyl diacryloyl zirconate, isopropyl (dioctyl phosphate) zirconate, isopropyl tri-n-stearoyl zirconate, isopropyl-4-aminobenzenesulfonyl di (dodecylbenzenesulfonyl) zirconate, isopropyl tricumylphenyl zirconate, isopropyl di ( 4-Aminobenzoyl) isostearoyl zirconate , Isopropyl tri (dioctyl pyrophosphate) zirconate, isopropyl tri (octyl butyl pyrophosphate) zirconate, tetraisopropyl di (dilauryl phosphite) zirconate, tetraoctyl di (ditridecyl phosphite) zirconate, tetraisopropyl di (ditridecyl phosphite) ) Zirconate,
Tetra (2,2-diallyloxymethyl-1 butoxy)
Di (ditridecyl) phosphite zirconate, diisostearoyl oxyacetate zirconate, isostearoyl methacryloyl oxyacetate zirconate, isostearoyl acryloyloxy acetate zirconate, di (dioctyl phosphate) oxyacetate zirconate, 4-aminobenzoyl isostearoyloxy Acetate zirconate, di (dioctyl pyrophosphate) oxyacetate zirconate,
Di (octylbutyl pyrophosphate) oxyacetate zirconate, diisostearoyl ethylene zirconate, isostearoyl methacryloyl ethylene zirconate, di (dioctyl phosphate) ethylene zirconate, 4-aminobenzoyl isostearoyl ethylene zirconate, di (dioctyl pyrophosphate) ) Ethylene zirconate, isopropyl dimethacryloyl isostearoyl zirconate, isopropyl triisostearoyl zirconate, tetraisopropoxy zirconium and the like can be mentioned, and a commercially available product can be used. In addition, these coupling agents are 1
One kind or two or more kinds can be mixed. As described above, as the composition of the thermosetting fluororesin powder coating material, 0.001 to 100 parts by weight of the coupling agent (c) is added to 100 parts by weight of the resin composition comprising the fluororesin (a) and the curing agent (b).
By blending 1.5 parts by weight, preferably 0.001 to 1.0 part by weight, the thermosetting property is excellent in weather resistance, acid resistance, etc., excellent in adhesion to stainless steel material and also excellent in impact resistance. A fluororesin-based powder coating composition is obtained.

When the amount of the coupling agent used in the composition of the present invention is less than 0.001 part by weight, a sufficient effect of improving the adhesiveness is not recognized, and when it exceeds 1.5 parts by weight, the appearance of the coating film appears. Properties and impact resistance. Examples of the epoxy resin used as the other component (d) of the composition of the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenoxy resin, novolac type epoxy resin, β-methylepichloro type epoxy resin, brominated type epoxy resin. Examples thereof include resins, cycloaliphatic epoxy resins, phenol compound-modified epoxy resins and hydrogenated epoxy resins thereof. These epoxy resins have a number average molecular weight of 350 to 50,000 and a softening point of 17
It is preferably 0 ° C. or lower, more preferably 160 ° C. or lower. When the number average molecular weight of the epoxy resin is less than 350, the storage stability of the powder coating is poor, and the number average molecular weight is 5,000.
If it exceeds 0, the appearance of the coating film tends to deteriorate. On the other hand, when the softening point of the epoxy resin exceeds 170 ° C, the appearance of the coating film tends to deteriorate. Commercially available products of such epoxy resin are, for example, Epicoat 828, Epicoat 1001, Epicoat 1002, Epicoat 1 manufactured by Shell Chemical Co., Ltd.
003, Epicoat 1003F, Epicoat 1004,
Epicoat 1004N, Epicoat 1007, Epicoat 1009, Epicoat 1055, Epicoat 505
0, Epicoat 5051, Epicoat 517, Epicoat 571, Epicoat 575, Epicoat 190P, Epicoat 872 [all trade names], Araldite AER6003 [trade name] manufactured by Asahi Chiba Co., Ltd., ECN-1273 manufactured by Ciba Geigy, ECN- 1280, ECN-1
299 [all trade names], D.C. manufactured by Dow Chemical Japan Co., Ltd. E. R. 732, D.I. E. R. 542 [all are trade names], Toto Kasei Co., Ltd. Epotote YDB400,
Epotote YH-434, Epotote ST-3000,
Epotote ST-5100, Epotote YH-325,
Phenothote YP-50 [all are trade names] and the like. These epoxy resins may be used alone or in combination of two or more. As described above, as the composition of the thermosetting fluororesin-based powder coating material, the epoxy resin (d) is replaced with the fluororesins (a) and (b).
0.0 with respect to 100 parts by weight of a resin composition comprising a curing agent
By blending 1 to 5.0 parts by weight, a thermosetting fluororesin-based powder coating composition having excellent weather resistance, acid resistance, etc., excellent adhesion to stainless steel materials and excellent impact resistance can be obtained. To be If the amount of the epoxy resin used in the composition of the present invention is less than 0.01 part by weight, a sufficient effect of improving the adhesiveness is not observed, and if it exceeds 5.0 parts by weight, the weather resistance of the coating film decreases. Or the gloss value may decrease.

The fluororesin (a) having a crosslinkable reactive group used as the component (a) of the composition of the present invention has a fluorine content of 10% by weight or more and a glass transition temperature of 35.
It is necessary to be 120 ° C. Such a fluororesin has a fluoroolefin unit and a unit having a crosslinkable reactive group. As the raw material of the fluoroolefin unit, for example, tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene, pentafluoropropylene, etc. can be used. It can be appropriately selected depending on the combination with the polymer component or the curing agent. These fluoroolefins may be used alone or in combination of two or more. Examples of the crosslinkable reactive group of the fluororesin used in the composition of the present invention include a hydroxyl group, a carboxyl group, a glycidyl group, an amide group, an amino group, a mercapto group, an isocyanate group, and an active halogen atom such as bromine and iodine. A hydroxyl group, a carboxyl group and a glycidyl group are particularly preferable as these crosslinkable reactive groups. The method of introducing such a crosslinkable reactive group into the fluororesin is
Method for copolymerizing fluoroolefin and monomer having crosslinkable reactive group, copolymer after copolymerizing fluoroolefin and monomer having substituent capable of decomposing to produce crosslinkable reactive group How to disassemble a part of
And a method of copolymerizing a fluoroolefin and a monomer having a functional group capable of reacting with a compound providing a crosslinkable reactive group, and then reacting a compound providing a crosslinkable reactive group with the functional group of the copolymer. There is a means of. The preferred monomer having a crosslinkable reactive group used in the composition of the present invention is a monomer having a hydroxyl group or a group capable of being converted into a hydroxyl group, which is a double bond copolymerizable with a fluoroolefin. It is possible to use those having, for example, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether,
Hydroxyalkyl vinyl ethers such as hydroxycyclohexyl vinyl ether, vinyl hydroxyacetate, vinyl hydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinyl hydroxyisobutyrate, and vinyl alcohols such as hydroxycyclohexanecarboxylate. Hydroxyalkyl allyl ethers such as hydroxyethyl allyl ether, hydroxypropyl allyl ether, hydroxybutyl allyl ether, hydroxyisobutyl allyl ether, hydroxy cyclohexyl allyl ether, allyl hydroxyacetate,
Esters of hydroxyalkylcarboxylic acids such as allyl hydroxypropionate, allyl hydroxybutyrate, allyl hydroxyvalerate, allyl hydroxyisobutyrate, allyl hydroxycyclohexanecarboxylate and allyl alcohol, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2- Examples thereof include hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate and hydroxypropyl methacrylate, and partially fluorine-substituted compounds thereof.

As the raw material for the hydroxyl group-containing unit, one or more of these may be selected and used. Further, it is desirable to use a vinyl-based or allyl-based compound because of its copolymerizability with fluoroolefin. Next, examples of the monomer having a carboxyl group used in the present invention include (meth) acrylic acid and carboxylalkyl allyl ether. Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, glycidyl vinyl ether, glycidyl allyl ether, and the like. Further, as a method of decomposing a part of the copolymer, after copolymerizing a monomer having a hydrolyzable ester group after polymerization, by hydrolyzing the copolymer, A method of producing a carboxyl group is exemplified. Further, in this way, in the direct curing reaction without the hydrolysis of the ester, the cross-linking bond can be formed by the transesterification reaction. The fluorine resin having a crosslinkable reactive group used in the thermosetting powder coating composition of the present invention needs to have a fluorine content of 10% by weight or more. This fluorine content is usually related to the composition ratio of the fluoroolefin unit in the fluororesin having a crosslinkable reactive group. However, it is also possible to increase or decrease this content by polymer reaction once the copolymer is produced. When the fluorine content in the fluororesin having a crosslinkable reactive group used in the composition of the present invention is less than 10% by weight, a coating film having sufficient weather resistance cannot be obtained. The preferred range of the fluorine content in the fluororesin is 10 to 72% by weight. The fluororesin (a) having a crosslinkable reactive group used in the thermosetting powder coating composition of the present invention has a crosslinkable reactive group and is strong and has an adhesive property due to the reaction with the curing agent (b). Although an excellent coating film can be obtained, the average molecular weight of the chain per one crosslinkable reactive group is preferably 250 to 25,000. When the average molecular weight of the copolymer chain per one crosslinkable reactive group present in the fluororesin molecule exceeds 25,000, the crosslinking becomes insufficient and the physical properties such as solvent resistance decrease, and when it is less than 250, The crosslink density becomes too high and flexibility tends to decrease.

The average molecular weight of the chain per one crosslinkable reactive group of the fluorine-containing copolymer in the composition of the present invention is represented by the following formula:

[Equation 1] Specifically, this average molecular weight is determined by the crosslinkable reaction group value (mgKO, such as hydroxyl value, acid value or epoxy value of the fluororesin.
H / g) can be calculated by a method such as IR spectrum, NMR spectrum and titration and calculated by the following formula.

[Equation 2] (Here, 56.1 is the molecular weight of KOH.) When the crosslinkable reactive group is an epoxy group, the epoxy equivalent corresponds to this value. The hydroxyl value of the fluororesin (a) having a hydroxyl group as a crosslinkable reactive group is 1 to 200 mgKOH
/ G, preferably 10 to 140 mgKOH / g, more preferably 25 to 120 mgKOH / g. Hydroxyl value is 1mgKOH
If it is less than / g, crosslinking will be insufficient and the physical properties will deteriorate.
If it exceeds 200 mgKOH / g, the crosslink density tends to be too high and the flexibility tends to decrease. The acid value of the fluororesin (a) having a carboxyl group as a crosslinkable reactive group is 1 to 200 mgKOH / g, preferably 3 to 140 m.
It is gKOH / g. When the acid value is less than 1 mgKOH / g,
If the cross-linking becomes insufficient and the physical properties decrease, and if it exceeds 200 mgKOH / g, the cross-linking density tends to be too high and the flexibility tends to decrease. The epoxy equivalent of the fluororesin (a) having an epoxy group as a crosslinkable reactive group is 100 to
15000 g / eq, preferably 300-14000 g /
eq. If it exceeds 15000 g / eq, the crosslinking tends to be insufficient and the physical properties are deteriorated. If the epoxy equivalent is less than 100 g / eq, the crosslinking density tends to be too high and the flexibility tends to decrease. Further, a fluororesin having an active halogen atom such as an amide group, an amino group, a mercapto group, an isocyanate group, bromine or iodine as a crosslinkable reactive group can be mentioned. Further, the glass transition temperature of the fluororesin used in the composition of the present invention needs to be 35 to 120 ° C, and preferably 40 to 100 ° C. When the glass transition temperature is less than 35 ° C., it becomes hard to be solid and cannot be used as a curable powder coating composition. Further, if the glass transition temperature exceeds 120 ° C., the softening point becomes too high and the flowability of the coating film deteriorates.

The fluororesin having a crosslinkable reactive group in the composition of the present invention can be synthesized by a conventionally known method, and a polymerization initiator acts on a monomer mixture in a predetermined ratio in the presence or absence of a catalyst. It can be polymerized by urging. Further, it can be produced by any method of solution polymerization, emulsion polymerization and suspension polymerization. When a fluororesin having a crosslinkable reactive group is obtained by emulsion polymerization or suspension polymerization, the dispersion medium is removed from the polymerization liquid and the pressure reduction degree is 10 mm.
It can be manufactured by evaporating and removing at Hg or less at 50 to 100 ° C., and then pulverizing with a milling machine such as a wheelet type, a vibration mill type, an impact type hammer mill type. When obtained by solution polymerization, the solvent of the polymerization liquid is removed, or the polymer is not put into a solvent that does not dissolve to precipitate a fluororesin having a crosslinkable reactive group, and the solvent is removed and then pulverized. Can be manufactured. The fluororesin having a crosslinkable reactive group used in the curable powder coating composition of the present invention is used as a solid resin, and the resin is a residual amount of a solvent (hereinafter, used to include a dispersion medium). The (heating loss) is preferably 2% or less. When a large amount of solvent remains in the fluororesin having a crosslinkable reactive group, the storage stability of the powder coating is poor, and after baking and curing of the powder coating, foaming, blistering, pinholes, etc. on the coating film occur. Is likely to occur, which is not preferable. In particular, it is preferable that the heating loss is 1% or less. The thermosetting powder coating composition of the present invention is a resin for a thermosetting powder coating having a crosslinkable reactive group in which the content of the fluororesin of component (a) is 50% by weight or less, preferably 30% by weight or less. It is preferable to replace. The thermosetting powder coating resin may have any one of a hydroxyl value, an acid value, an epoxy equivalent, or 2 of them.
Examples thereof include polyester resins and acrylic resins having crosslinkable reactive groups corresponding to 3 to 3. The polyester resin having a crosslinkable reactive group is a solid resin having an average of 2 or more crosslinkable reactive groups per molecule at room temperature and a number average molecular weight of 1,000 to 20,000, preferably 1,500 to 8,000. When the group is a hydroxyl group, the hydroxyl value is 10 to 300 mgKOH / g, preferably 10 to
200 mg KOH / g resin can be used. Also,
When the crosslinkable reactive group is a carboxyl group, the acid value is 10
300 mg KOH / g, preferably 10-200 mg KOH / g resin can be used. It can be obtained by directly esterifying the carboxylic acid capable of forming the polyester resin and a polyhydric alcohol mainly containing ethylene glycol, or a commercially available product can be used. Examples of the carboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, β-oxypropionic acid, oxalic acid, maleic anhydride, trimellitic acid, pyromellitic acid and The polyhydric alcohol is preferably selected from the group consisting of a mixture thereof, and examples of the polyhydric alcohol include ethylene glycol, propanediol, butanediol, pentanediol, 1,6-hexanediol, neopentyl glycol, and 2,2. It is preferably selected from the group consisting of diethylpropanediol, cyclohexanediol, glycerin, trimethylolpropane, pentaerythritol and mixtures thereof.

The acrylic resin having a crosslinkable reactive group is a resin which is solid at room temperature and has an average of two or more crosslinkable reactive groups per molecule, and preferably has a number average molecular weight of 1
000 to 20,000, when the crosslinkable reactive group is a hydroxyl group, the hydroxyl value is 10 to 300 mgKOH / g, preferably 10
200 mg KOH / g resin can be used. Also,
When the crosslinkable reactive group is a carboxyl group, the acid value is 10
A resin of 300 mgKOH / g, preferably 10 to 200 mgKOH / g can be used, and when the crosslinkable reactive group is an epoxy group, a resin having an epoxy equivalent of 200 to 1500 g / eq can be used. This acrylic resin is a copolymerizable vinyl monomer having a hydroxyl group, a carboxyl group, a glycidyl group, an amide group, an amino group, a mercapto group, an isocyanate group and a halogen atom, and other vinyl-based monomers capable of being copolymerized therewith. It is obtained by copolymerizing with the body. Examples of the vinyl monomer containing a hydroxyl group include mono (meth) acrylic acid ester of polyhydric alcohol, monotonic acid ester, allyl alcohol,
Preferable examples include monoallyl ethers of polyhydric alcohols and hydroxyethyl vinyl ether. Examples of polyhydric alcohols that can be used for the hydroxyl group-containing vinyl-based monomer include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and 1 Examples of the polyhydric alcohol include dihydric alcohols such as 1,3-butylene glycol, 1,4-butylene glycol and 1,6-hexanediol; glycerin, trimethylolpropane, trimethylolethane and pentaerythritol. In addition, fumaric acid dihydroxyethyl ester, fumaric acid butylhydroxyethyl ester and the like can also be used. Examples of the vinyl monomer containing a carboxyl group include unsaturated acids containing a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid. Examples of vinyl monomers containing an epoxy group include glycidyl acrylate, glycidyl methacrylate and β-
Methylglycidyl acrylate and β-methylglycidyl methacrylate can be preferably mentioned. Other copolymerizable vinyl monomers include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, methacryl Butyl acid, methacrylic acid alkyl esters such as 2-ethylhexyl methacrylate; styrene such as styrene and α-methylstyrene or derivatives thereof; other vinyl acetate, vinyl propionate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, Vinyl stearate, fumaric acid dialkyl ester, itaconic acid dialkyl ester, halogen-containing vinyl monomer, silicon-containing vinyl monomer, ethylene and the like can be mentioned, and they are used alone or as a mixture. Door can be.

The acrylic resin having a crosslinkable functional group used in the present invention can be prepared by the conventionally known emulsion polymerization method, suspension polymerization method, solution polymerization method or the like in the presence of a usual polymerization initiator in the presence of the vinyl monomer. In addition to being produced by copolymerizing, a commercially available product can also be used. When the number average molecular weight of the acrylic resin having a crosslinkable functional group is less than 1000, the resulting coating film has insufficient mechanical strength such as impact resistance and flexibility, and when it exceeds 20,000. The resulting coating film tends to have poor appearance such as smoothness and sharpness. In the case of a resin having a hydroxyl group as the functional group of the polyester resin having the crosslinkable functional group and the acrylic resin, the hydroxyl value is 10 to 300 mgKOH / g.
Is preferable, and the hydroxyl value is 10 mgKOH /
If it is less than g, the cross-linking density is low, so that sufficient physical properties of the coating film may not be obtained, and if it exceeds 300 mgKOH / g, the coating film tends to be hard and brittle. Further, in the case of a resin having a carboxyl group as a functional group, those having an acid value in the range of 10 to 300 mgKOH / g are preferable,
If the acid value is less than 10 mgKOH / g, the cross-linking density is low and there is a risk that sufficient coating film physical properties may not be obtained.
If it exceeds g, the coating film tends to be hard and brittle. In the case of a resin having a functional group having an epoxy group, it is preferable that the epoxy equivalent is in the range of 200 to 1500 g / eq, and if the epoxy equivalent is less than 200 g / eq, the coating film tends to be hard and brittle. Epoxy equivalent is 15
If it exceeds 00 g / eq, the crosslink density is low and sufficient coating film physical properties may not be obtained. In the thermosetting powder coating composition of the present invention, 50% by weight or less, preferably 30% by weight or less of the component (a) fluororesin can be replaced with a resin for thermoplastic powder coating. Examples of the thermoplastic resin used in the composition of the present invention include acrylic resins, polyester resins, nylon resins and fluororesins, and those having a softening point of the thermoplastic resin of 60 to 200 ° C. are preferable.
Examples of commercially available thermoplastic acrylic resins include DIALNAL BR-60 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.), and commercially available thermoplastic polyester resins include, for example, Byron 560 (produced by Toyobo Co., Ltd.). , Trade name], as a commercial product of the thermoplastic nylon resin, for example, Olgasol 3502 [manufactured by Nippon Rilsan Co., Ltd., trade name], as a commercial product of the thermoplastic fluororesin, for example, Kainer 500 [manufactured by Penwald Chemicals, Product name], Kainer ADS
[Penwald Chemicals, trade name], Kynar S
L [manufactured by Penwald Chemicals, trade name] and the like.

On the other hand, the curing agent used as the component (b) in the thermosetting powder coating composition of the present invention is a blocked isocyanate compound such as isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane. Diisocyanate,
Hexamethylene diisocyanate, polyisocyanate compounds such as dicyclohexyl methane diisocyanate and diisocyanates, trimers and polyisocyanate compounds modified with polyhydric alcohols such as trimethylol propane are used for ε-caprolactam, phenol and benzyl. Examples thereof include compounds blocked with a blocking agent such as alcohol and methylethylketoxime. As the blocked isocyanate compound, a compound that is solid at room temperature can be preferably used. Further, aliphatic dibasic acids such as fumaric acid, succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid, acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride, and an acid value of 10 ~ 300 mgKOH / g, glass transition temperature 30 ~ 120 ° C, number average molecular weight 1000 ~ 1
5000 polyester resin or acrylic resin, dicyandiamide and dicyandiamide derivative, imidazole and imidazole derivative, dibasic acid dihydrazide, diaminodiphenylmethane, amine compound such as cyclic amidine compound, melamine resin, terephthalic acid diglycidyl ester, paraoxybenzoic acid diglycidyl ester ,
Triglycidyl isocyanurate, glycidyl compound such as spiroglycol diglycidyl ether, alicyclic epoxy resin, 1,4-bis (2-hydroxyethoxy) benzene, bishydroxyethyl terephthalate, styrene-allyl alcohol copolymer, spiroglycol, Tris (2-hydroxyethyl) isocyanurate, hydroxyl value 10-300 mgKOH / g, glass transition temperature 30-
120 ° C. and number average molecular weight of 1,000 to 20,000
And a compound having a hydroxyl group such as an acrylic resin. The glass transition temperature of the thermosetting powder coating composition of the present invention is preferably 35.
To 120 ° C, and particularly preferably 40 to 100 ° C. If the glass transition temperature is lower than 35 ° C, it may not be solid and may not be used as a thermosetting powder coating composition. Further, when the glass transition temperature exceeds 120 ° C., the softening point becomes too high and the flow of the coating film becomes poor. Further, the heat loss of the thermosetting powder coating composition of the present invention is 2
% Or less, particularly preferably 1% or less. If the loss on heating exceeds 2%, the storage stability of the powder coating is poor,
Further, after baking and curing the powder coating material, foaming, blistering, pinholes and the like are likely to occur in the coating film, which is not preferable.

The blending ratio in the composition of the present invention is (a)
60 to 97% by weight of a fluororesin having a crosslinkable reactive group,
(B) 100 parts by weight of a resin composition composed of 2 components of 3 to 40% by weight of a curing agent capable of reacting with a crosslinkable reactive group of the fluororesin to form a crosslink (c) a synthetic wax or a natural wax 0.01 to 10 parts by weight, (d) 0.001 to 1.5 parts by weight of the compound having a coupling group and /
Alternatively, 0.01 to 5.0 parts by weight of an epoxy resin is blended. The ratio of the component (a) and the component (b) is appropriately selected depending on the ratio and type of the crosslinkable reactive group.
The thermosetting powder coating composition of the present invention may contain an additive usually used in coating compositions as a third component. As the additive, for example, a modified resin, a coloring pigment (for example, titanium dioxide, red iron oxide, yellow iron oxide, an inorganic pigment such as carbon black, phthalocyanine blue, phthalocyanine green, a quinacridone red pigment, an isoindolinone yellow organic pigment, etc. Pigments), extenders such as talc, silica, calcium carbonate, metal powders such as aluminum powder and stainless powder, mica powder and leveling agents, ultraviolet absorbers, heat deterioration inhibitors, antifoaming agents and other additives. If desired, one kind or two or more kinds may be blended. The composition of the present invention can be prepared by a method similar to the known method for producing a thermosetting powder coating material.
The thermosetting powder coating composition produced as described above usually has a particle size of 2 to 200 μm or less, and is made of stainless steel, iron, aluminum, copper, zinc or alloys thereof such as stainless steel, brass and the like. It is possible to form a good coating film by uniformly coating the same metal with a commercially available electrostatic powder coating machine, fluidized dipping device, etc., and then baking it in a hot air oven, infrared oven, dielectric heating oven, etc. it can. As described above, as the composition of the thermosetting fluororesin-based powder coating material, the synthetic wax or the natural wax (c) is added in an amount of 0.01 to 100 parts by weight based on 100 parts by weight of the total amount of the fluororesin (a) and the curing agent (b). 10
Parts by weight, (d) compound having coupling group 0.00
By blending 0.01 to 5.0 parts by weight of a compound having 1 to 1.5 parts by weight and / or an epoxy resin, excellent weather resistance, acid resistance, adhesion to stainless steel materials, and water repellency, A thermosetting fluororesin-based powder coating composition excellent in slipperiness is obtained.

[0016]

EXAMPLES Next, the present invention will be described in more detail with reference to production examples of fluororesins having a crosslinkable reactive group and examples and comparative examples of thermosetting powder coating compositions, but the present invention is not limited to these. Not something. The physical properties in the examples were evaluated by the following methods. A sulfuric acid aqueous solution having an acid resistance of 20% was dropped on a test piece with a dropper, a spot test was performed, and the state of change in the coating film after 200 hours at 20 ° C. was observed and evaluated. Weather resistance JIS K 5400 (1990) 9.8.1 Accelerated weather resistance sunshine carbon arc lamp type, the gloss retention and color difference after 3000 hours test JIS D 0205 7.
It evaluated according to 6. Adhesiveness After dipping the test plate in boiling water for 2 hours, JIS K 54
According to the cross-cutting method of 00 (1990) 8.5.1, 100 squares were formed and the cellophane tape was pressure-bonded and then rapidly peeled off. Smoothness The visual evaluation was made by the shape of the fluorescent lamp when the fluorescent lamp was copied on the coating film. Sliding property of coating film HEIDON-10, static friction coefficient measuring device manufactured by Shinto Kagaku Co., Ltd.
Using a mold, the coefficient of static friction was determined and evaluated. Water repellency of the coating film The critical surface tension was determined by the contact angle method and evaluated. Impact resistance After immersing the test plate in boiling water for 2 hours, JIS K 54
00 (1990) 8.3.2. The evaluation criteria for each evaluation item are as follows.

1) Acid resistance: good; almost no change Poor; Severe changes such as blister and gloss are observed. 2) Weather resistance: Good; almost no change is observed. (Gloss retention rate is 8
5% or more and a color difference of less than 1.5) Poor; A drastic change is observed. (Gloss retention rate is 85%
Less than and / or color difference of 1.5 or more) 3) Smoothness: good; when the fluorescent lamp is viewed on the coating film, the fluorescent lamp has no distortion. Defective: When the fluorescent lamp was copied on the coating film, the fluorescent lamp was distorted. 4) Adhesion: Good; no peeling is observed. (100/100) Poor; one or more peels are observed. (0/100 to 99
/ 100) 5) Impact resistance: good; 500 g, 50 cm, no coating film abnormality. Defective: Abnormalities such as cracks, cracks, and peeling at 500 g and 50 cm. 6) Sliding property: good; less than 0.20 poor; 0.20 or more 7) water repellency: good; less than 23 poor; 23 or more

The raw materials used for blending the compositions of Examples and Comparative Examples are as follows. 1) LF-710F, manufactured by Asahi Glass Co., Ltd., trade name, hydroxyl value 50 mgKOH / g, glass transition temperature 68 ° C., fluorine content 30%. 2) Polyflon, manufactured by Daikin Industries, Ltd., trade name, polytetrafluoroethylene, thermoplastic fluororesin. 3) Adduct B-1530, manufactured by Huls, trade name, ε
-Caprolactam block isophorone diisocyanate, NCO equivalent 280 g / eq. 4) Adduct B-1065, manufactured by Huls, trade name, ε
-Caprolactam block isophorone diisocyanate, NCO equivalent 400 g / eq. 5) Adduct BF-1540, manufactured by Huls, trade name,
Uretdione compound, solid content 100%, NCO equivalent 28
0 g / eq. 6) Powderlink 1174, manufactured by Cyanamid, trade name, amino resin type curing agent, average molecular weight 350,
Functional group equivalent 90-125 g / eq. 7) TYPURE R-960, manufactured by DuPont, trade name, titanium dioxide. 8) Ceridust 3620, Hoechst, trade name, polyethylene wax, melting point 125 ° C. 9) Lanco Wax PE1500F, manufactured by Langer Co., trade name, polyethylene wax, melting point 140 ° C. 10) Viscor 330-P, manufactured by Sanyo Chemical Industries, Ltd.,
Trade name, polypropylene wax, melting point 152 ° C. 11) TSL-8340, manufactured by Toshiba Silicone Co., Ltd., trade name, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane. 12) TSL-8350, manufactured by Toshiba Silicone Co., Ltd., trade name, γ-glycidoxypropyltrimethoxysilane. 13) TSL-8370, manufactured by Toshiba Silicone Co., Ltd., trade name, γ- (meth) acryloxypropyltrimethoxysilane. 14) KR-TTS, manufactured by Ajinomoto Co., Inc., trade name, isopropoxy group-containing titanate coupling agent. 15) KR-41B, manufactured by Ajinomoto Co., Inc., trade name, isopropoxy group-containing titanate coupling agent. 16) KR-44, a trade name, manufactured by Ajinomoto Co., Inc., a titanate coupling agent containing an isopropoxy group. 17) AL-M, manufactured by Ajinomoto Co., Inc., trade name, acetoalkoxyaluminum diisopropylate. 18) Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.,
Brand name, bisphenol A type epoxy resin, number average molecular weight 380. 19) Epicoat 1002, Yuka Shell Epoxy Co., Ltd.
Product name, bisphenol A type epoxy resin, number average molecular weight 1060, softening point 83 ° C. 20) Araldite AER6003, manufactured by Asahi Ciba Co., Ltd., trade name, bisphenol A type epoxy resin, number average molecular weight 1500, softening point 97 ° C. 21) Epicoat 1009, Yuka Shell Epoxy Co., Ltd.
Product name, bisphenol A type epoxy resin, number average molecular weight 3750, softening point 152 ° C. 22) Araldite ECN1299, manufactured by Ciba Geigy, trade name, novolac type epoxy resin, number average molecular weight 1270, softening point 99 ° C. 23) Epotote ST-5100, manufactured by Tohto Kasei Co., Ltd., trade name, hydrogenated bisphenol A type epoxy resin, number average molecular weight 2000. 24) Phenothote YP-50, manufactured by Tohto Kasei Co., Ltd., trade name, phenoxy resin, number average molecular weight 11800, softening point 150 ° C. 25) Epicoat 1004, Yuka Shell Epoxy Co., Ltd.
Product name, bisphenol A type epoxy resin, number average molecular weight 1600, softening point 98 ° C. 26) Epicoat 1055, Yuka Shell Epoxy Co., Ltd.
Product name, bisphenol A type epoxy resin, number average molecular weight 1350, softening point 94 ° C. 27) DER732, Dow Chemical Japan Co., Ltd., trade name, polyglycol type liquid epoxy resin, number average molecular weight 650. 28) DER542, Dow Chemical Japan KK, trade name, brominated epoxy resin, number average molecular weight 650, softening point 57 ° C. 29) Findex M-8540, manufactured by Dainippon Ink and Chemicals, Inc., trade name, polyester resin, acid value 220
mgKOH / g, number average molecular weight: 1900. 30) John Krill 680, manufactured by Johnson Wax,
Trade name, acrylic resin, acid value 215 mgKOH / g, number average molecular weight: 1800. 31) ALMATEX PD-6730, Mitsui Toatsu Chemicals
Product name, acrylic resin, epoxy equivalent 460g
/ Eq, number average molecular weight: 3300. 32) PRIMID XL-552, manufactured by Zarome and Haas Company, trade name, β-hydroxyalkylamide. 33) MPP-230F, manufactured by Micro Powder Co., trade name, polyethylene wax, melting point 245 ° C. 34) ALMATEX AP-3304, Mitsui Toatsu Chemicals
Co., Ltd., trade name, acrylic resin, hydroxyl value 50 mgKOH /
g, number average molecular weight 3000. 35) Fine Dick A-207S, manufactured by Dainippon Ink and Chemicals, Inc., trade name, acrylic resin, epoxy equivalent 5
08 g / eq, number average molecular weight 3500. 36) ALMATEX AP-3299, Mitsui Toatsu Chemicals
Co., Ltd., trade name, acrylic resin, acid value 33 mgKOH / g,
Number average molecular weight 3300. 37) Ester Resin ER-6650, Nippon Ester
Co., Ltd., trade name, polyester resin, hydroxyl value 30 mg KO
H / g, number average molecular weight 4100. 38) Ularak P-3500, Yupica DSM Resins
Co., Ltd., trade name, polyester resin, acid value 33-38 mg
KOH / g, number average molecular weight 2900. 39) Diinal BR-60, manufactured by Mitsubishi Rayon Co., Ltd.
Trade name, thermoplastic acrylic resin, softening point 100-140
° C. 40) Byron 560, manufactured by Toyobo Co., Ltd., trade name, thermoplastic polyester resin, softening point 110 ° C. 41) Organsol 3502, Nippon Rilsan Co., Ltd. product name, nylon powder, softening point 135-160 degreeC. 42) Kainer 500, manufactured by Penwalt Chemicals,
Trade name, vinylidene fluoride, softening point 160-170 ° C. 43) Kainer ADS, manufactured by Penwald Chemicals,
Trade name, thermoplastic fluororesin, softening point 87-93 ° C.

In the following description, [parts] and [%] are based on weight. Production Example 1 In a pressure resistant reactor with a stirrer made of stainless steel with an internal volume of 300cc,
Liquid nitrogen was charged with 157 g of t-butanol, 16 g of cyclohexyl vinyl ether (c-HxVE), 9 g of isobutyl vinyl ether (isoBVE), 25 g of hydroxybutyl vinyl ether (HBVE), 1 g of potassium carbonate and 0.07 g of azobisisobutyronitrile (AIBN). The dissolved air was removed by solidification degassing with. After that, chlorotrifluoroethylene (CTFE) 50
g was introduced and the temperature was gradually raised. Then, the reaction was continued under stirring while maintaining the temperature at 65 ° C., and after 10 hours, the reactor was water-cooled to stop the reaction. After cooling to room temperature, unreacted monomer was extracted and the reactor was opened. Then, the mixture was heated to 60 ° C., the dispersion medium was removed under a reduced pressure of 1 mmHg for 24 hours, and then pulverized with an impact hammer mill to give a hydroxyl value of 120.
A fluororesin (A-1) containing mgKOH / g, a glass transition temperature of 45 ° C., and a heating loss of 2% or less was obtained. Production Examples 2 to 5 Monomer mixtures having the composition ratios shown in Table 1 for each Production Example were polymerized in the same manner as in Production Example 1. However, each t
-The amounts of butanol and AIBN were appropriately changed depending on the compounding conditions to obtain a fluororesin having a crosslinkable reactive group shown in Table 1. Table 1 also shows the hydroxyl value, glass transition temperature, and heating loss of the obtained fluororesins (A-2 to 5) having a crosslinkable reactive group.

[0020]

[Table 1]

Note 1) TFE: Tetrafluoroethylene 2) EVE: Ethyl vinyl ether 3) Measured by the heat loss of JIS K 5407 (1990) 5. Production Example 6 100 parts of a polymer obtained by polymerizing a monomer mixture having the composition ratio shown in Table 1 in the same manner as in Production Examples 1 to 5 was dissolved in 100 parts of xylene to give 0.9 part of succinic anhydride. And 0.05 part of triethylbenzylammonium chloride were added, and the mixture was heated to 100 ° C. in a four-necked flask equipped with a stirrer, stirred for 3 hours, and then cooled. Then the temperature 60
After heating to ℃ and removing the dispersion medium for 24 hours under a reduced pressure of 1 mmHg, it was pulverized by an impact hammer mill to obtain a fluororesin (A-6) powder containing a hydroxyl group and a carboxyl group. Table 1 shows the hydroxyl value, acid value, glass transition temperature, and weight loss on heating of the obtained fluororesin (A-6). Production Example 7 In a pressure resistant reactor with a stirrer made of stainless steel with an internal volume of 300cc,
157 g of t-butanol, 18 g of cyclohexyl vinyl ether (c-HxVE), 10 g of isobutyl vinyl ether (isoBVE), 20 g of glycidyl vinyl ether (GVE), 1 g of potassium carbonate and 0.07 g of azobisisobutyronitrile (AIBN) were charged, and liquid nitrogen was used. Dissolved air is removed by solidification degassing. After that, 52 g of chlorotrifluoroethylene (CTFE)
Is introduced and the temperature is gradually raised. Then, the temperature is maintained at 65 ° C., the reaction is continued under stirring, and after 10 hours, the reactor is water-cooled to stop the reaction. After cooling to room temperature, unreacted monomer is extracted and the reactor is opened. Next, the dispersion medium was heated at 60 ° C. under a reduced pressure of 1 mmHg for 24 hours to remove the dispersion medium, and then pulverized with an impact hammer mill to obtain a glycidyl group-containing fluororesin (A-7). Obtained fluororesin (A-
The epoxy equivalent of 7) was 500 g / eq, the glass transition temperature was 49 ° C., and the heating loss was 2% or less. Production Examples 8 to 10 A monomer mixture having the composition ratio shown in Table 2 for each Production Example was polymerized in the same manner as in Production Example 1, the dispersion medium was removed, and then the mixture was crushed with an impact hammer mill. However, each t-
By appropriately changing the amounts of butanol and AIBN depending on the compounding conditions, a glycidyl group-containing fluororesin shown in Table 2 was obtained. Table 2 also shows the epoxy equivalent, glass transition temperature, and heating loss of the obtained fluororesin (A-8 to 10) having a crosslinkable reactive group.

[0022]

[Table 2]

Note 1) TFE: tetrafluoroethylene 2) EVE: ethyl vinyl ether 3) VA: vinyl acetate 4) AGE: allyl glycidyl ether 5) Measured by the heat loss of JIS K 5407 (1990) 5 Production Example 11 Production Example 7 CTFE52g, c-HxVE
28 g, hydroxybutyl vinyl ether (HBVE)
20 g of a fluorinated copolymer was obtained. Next, 100 parts of this polymer was dissolved in 100 parts of xylene, 3.6 parts of succinic anhydride and 0.05 part of triethylbenzylammonium chloride were added, and the mixture was heated to 100 ° C. in a four-necked flask equipped with a stirrer. After stirring for 3 hours, the mixture was cooled. Then, heat to a temperature of 60 ° C. and reduce the pressure to 1 mmHg for 24 hours.
After removing the dispersion medium over time, it is crushed with an impact hammer mill to give a carboxyl group-containing fluororesin (A-11).
A powder was obtained. The acid value of the obtained fluororesin (A-11) was 19.5 mgKOH / g, the glass transition temperature was 47 ° C., and the heating loss was 2% or less. Production Examples 12 to 14 In the same manner as in Production Example 11, a monomer mixture having a composition ratio shown in Table 3 was polymerized, and then an addition reaction of succinic anhydride was performed to obtain a fluororesin containing a carboxyl group. It was However, the amounts of t-butanol and AIBN for each polymerization were appropriately changed depending on the compounding conditions.
The obtained carboxyl group-containing fluororesin (A-12 to 1
The acid value of 4), the glass transition temperature, and the weight loss upon heating are also shown in Table 3.

[0024]

[Table 3]

Note 1) Isopropyl vinyl ether Examples 1 to 17 and Comparative Examples 1 to 3 Examples of thermosetting powder coating compositions containing a compound having a coupling group as the component (d) in Examples 1 to 17 Listed. All the components of the compositions of Examples 1 to 17 and Comparative Examples 1 to 3 shown in Table 4-1 and Table 2 are homogenized for about 1 minute with a dry blender [trade name, Henschel mixer, manufactured by Mitsui Kakoki Co., Ltd.]. Extruder kneader [trade name, Busco Kneader PR46, B under a temperature condition of 80 to 100 ° C.
[made by uss] was used for melt kneading, and after cooling, finely pulverized by a hammer type impact pulverizer. Then, it was sieved with a 180 mesh wire mesh to obtain powder coatings 1 to 17 and comparative coatings 1 and 2. As Comparative Example 3, polyflon (PTFE) manufactured by Daikin Industries, Ltd. was used. Examples 1 to 17 and Comparative Examples 1 to 3 of the obtained powder coating material were treated with an electrostatic powder coating machine.
0.8 mm thick stainless steel (SUS304 HL) plate that has been subjected to hairline processing and has been degreased with alkali (soaked in a NaOH aqueous solution at a liquid temperature of 50 ° C for 5 minutes, thoroughly washed with deionized water and dried at room temperature) It is coated so as to have a thickness of 50 to 60 μm, and Examples 1 to 4, 6 to 17 and Comparative Examples 1 to
No. 2 was 190 ° C. for 20 minutes, Example 5 was 250 ° C., 5
For 3 minutes, Comparative Example 3 was baked at 380 ° C. for 20 minutes to obtain a test plate. The test plate thus obtained was tested by the method described below. The results are shown in Table 5-1 and 2.

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

[Table 6]

[0029]

[Table 7]

[0030]

[Table 8]

[0031]

[Table 9]

[0032]

[Table 10]

[0033]

[Table 11]

Examples 18 to 34 and Comparative Examples 4 to 5 Examples 18 to 34 are examples of thermosetting powder coating compositions containing an epoxy resin as the component (d). Examples 18 to 34 and Comparative Examples 4 to 5 shown in Table 4-3 to 4
After uniformly mixing all the components of the composition in a dry blender (trade name, Henschel Mixer, manufactured by Mitsui Kakoki Co., Ltd.) for about 1 minute, the mixture is extruded and kneaded under a temperature condition of 80 to 100 ° C. [trade name, Busco Kneader]. PR46, made by Buss]
Was melt-kneaded, and after cooling, finely pulverized with a hammer type impact pulverizer. Then, it was sifted through a 180 mesh wire mesh to obtain powder coatings 18 to 34 and comparative coatings 4 to 5. Examples 18 to 34 and Comparative Examples 4 to 5 of the obtained powder coatings
Is subjected to hairline processing with an electrostatic powder coating machine and degreased with alkali (soaked in a NaOH aqueous solution at a liquid temperature of 50 ° C for 5 minutes, thoroughly washed with deionized water and dried at room temperature)
It was coated on a 0.8 mm thick stainless steel (SUS304 HL) plate so as to have a thickness of 50 to 60 μm.
21, 23 to 34 and Comparative Examples 4 to 5 are 190 ° C. and 20
For 15 minutes, in Example 22, baking was performed at 250 ° C. for 5 minutes to obtain a test plate. The test plate thus obtained was tested by the method described below. The results are shown in Table 5-3 to 4. Examples 35 to 48, Comparative Examples 6 to 9 In Examples 35 to 40, glycidyl group-containing fluororesin (a).
And an example of a thermosetting powder coating composition comprising a curing agent (b) having a carboxyl group, Examples 41 to 48 comprising a fluororesin containing a carboxyl group (a) and a curing agent (b) having a glycidyl group. Examples of thermosetting powder coating compositions are given. Example 3 shown in Tables 6-1 to 6 and Table 6-4
5 to 48, and all components of the compositions of Comparative Examples 6 to 9 were uniformly mixed for about 1 minute with a dry blender [trade name, Henschel mixer, manufactured by Mitsui Kakoki Co., Ltd.], and then 80 to 12
The mixture was melt-kneaded using an extrusion kneader [trade name, Busconieder PR46, manufactured by Buss] under a temperature condition of 0 ° C., cooled, and then finely pulverized by a hammer-type impact pulverizer. Then 180
The powder coatings 35 to 48 and the comparative coatings 6 to 9 were obtained by sieving with a mesh wire mesh. Example 35 of the obtained powder coating material
~ 48 and Comparative Examples 6 to 9 were subjected to hairline processing with an electrostatic powder coating machine, and alkali degreasing (liquid temperature 50 ° C Na
After soaking in an OH aqueous solution for 5 minutes, a degreasing solution was thoroughly washed with pure water and dried at room temperature. A stainless steel (SUS304 HL) plate having a thickness of 0.8 mm was coated to a thickness of 50 to 60 μm, and 190 ° C. Then, baking was performed for 20 minutes to obtain a test plate. A coating film performance test was conducted on the obtained test plate by the same method as described above. The results are shown in Tables 1 and 2 of Table 7.

[0035]

[Table 12]

[0036]

[Table 13]

[0037]

[Table 14]

[0038]

[Table 15]

[0039]

[Table 16]

[0040]

[Table 17]

[0041]

[Table 18]

[0042]

[Table 19]

[0043]

[Table 20]

[0044]

[Table 21]

[0045]

[Table 22]

[0046]

[Table 23]

Examples 49 to 62, Comparative Examples 10 to 13 In Examples 49 to 54, a glycidyl group-containing fluororesin (a) was used.
And an example of a thermosetting powder coating composition comprising a curing agent (b) having a carboxyl group, Examples 55 to 61 comprising a fluorocarbon resin containing a carboxyl group (a) and a curing agent (b) having a glycidyl group. An example of a thermosetting powder coating composition was given in Example 62 as an example of a thermosetting powder coating comprising a carboxyl-containing fluororesin (a) and a β-hydroxyalkylamide compound. All the components of the compositions of Examples 49 to 62 and Comparative Examples 10 to 13 shown in Tables 6 to 5 and 6 to 8 are dry blended [trade name, Henschel mixer, Mitsui Kakoki Co., Ltd. Manufactured for 1 minute, then melt-kneaded using an extrusion kneader [trade name, Busconieder PR46, manufactured by Buss] at a temperature condition of 80 to 120 ° C., and after cooling, hammer-type impact crusher Finely crushed with. Then, it was sieved with a 180 mesh wire mesh to obtain powder coatings 49 to 62 and comparative coatings 10 to 13. Examples 49 to 62 and Comparative Examples 10 to 13 of the obtained powder coatings
Is subjected to hairline processing with an electrostatic powder coating machine and degreased with alkali (soaked in a NaOH aqueous solution at a liquid temperature of 50 ° C for 5 minutes, thoroughly washed with deionized water and dried at room temperature)
It was painted on a 0.8 mm thick stainless steel (SUS304 HL) plate to a thickness of 50 to 60 μm,
Baking was performed for 0 minutes to obtain a test plate. A coating film performance test was conducted on the obtained test plate by the same method as described above. The results are shown in Table 7-3 to 4. Examples 63 to 73, Comparative Examples 14 to 18 Thermosetting in which 50% by weight or less of the fluororesin of component (a) is replaced with a thermosetting powder coating resin having a crosslinkable reactive group in Examples 63 to 67. Examples of the heat-resistant powder coating composition, in which, in Examples 68 to 73, 50% by weight or less of the fluororesin of the component (a) is replaced with a resin for thermoplastic powder coating, Was mentioned. Examples 63 to 73 shown in Table 8-1 and Table 8-2 and Comparative Example 14 shown in Table 3-3.
After uniformly mixing all the components of the composition of 18 with a dry blender [trade name, Henschel mixer, manufactured by Mitsui Kakoki Co., Ltd.] for about 1 minute, at a temperature condition of 80 to 120 ° C., an extrusion kneader [trade name, Busco kneader PR46, manufactured by Buss] was melt-kneaded, cooled, and then finely pulverized with a hammer-type impact pulverizer. Then, it was sieved with a 180-mesh wire mesh to obtain powder coatings 63 to 73 and comparative coatings 14 to 18. The obtained powder coating materials of Examples 63 to 73 and Comparative Examples 14 to 18 were subjected to hairline processing with an electrostatic powder coating machine, and alkali degreasing (5% in a NaOH aqueous solution at a liquid temperature of 50 ° C. was applied).
After soaking for 1 minute, the degreasing solution was thoroughly washed with pure water and dried at room temperature.
HL) 50 to 60 μm on the plate,
A test plate was obtained by baking at 0 ° C. for 20 minutes. A coating film performance test was conducted on the obtained test plate by the same method as described above. The test methods and test results are shown in Tables 9-1 and 9-2.

[0048]

[Table 24]

[0049]

[Table 25]

[0050]

[Table 26]

[0051]

[Table 27]

[0052]

[Table 28]

[0053]

[Table 29]

[0054]

[Table 30]

[0055]

[Table 31]

[0056]

[Table 32]

[0057]

[Table 33]

[0058]

[Table 34]

[0059]

[Table 35]

[0060]

[Table 36]

[0061]

[Table 37]

Examples 74-89, Comparative Examples 19-23 50% by weight of the component (a) fluororesin in Examples 74-78.
An example of a thermosetting powder coating composition in which the following is replaced with a resin for thermosetting powder coating having a crosslinkable reactive group is shown in Examples 79 to 84 in which 50% by weight or less of the fluororesin of component (a) is used. Examples of thermosetting powder coating compositions obtained by substituting the resin for thermoplastic powder coatings in Examples 85 to 89, in which an epoxy resin and a coupling agent as component (d) are used in combination. I gave an example. Examples 74 to 89 and Comparative Examples 19 to 23 shown in Table 8-4 to 6 and Table 8-7.
After uniformly mixing all the components of the composition in a dry blender (trade name, Henschel Mixer, manufactured by Mitsui Kakoki Co., Ltd.) for about 1 minute, the mixture is extruded and kneaded under a temperature condition of 80 to 120 ° C. [trade name, Busconieder. PR46, made by Buss]
Was melt-kneaded, and after cooling, finely pulverized with a hammer type impact pulverizer. Then, it was sieved with a 180-mesh wire mesh to obtain powder coatings 74 to 89 and comparative coatings 19 to 23. The obtained powder coatings of Examples 74 to 89 and Comparative Examples 19 to 23 were subjected to hairline processing with an electrostatic powder coating machine, and alkali degreasing (5% in a NaOH aqueous solution at a liquid temperature of 50 ° C was used.
After soaking for 1 minute, the degreasing solution was thoroughly washed with pure water and dried at room temperature.
HL) 50 to 60 μm on the plate,
A test plate was obtained by baking at 0 ° C. for 20 minutes. A coating film performance test was conducted on the obtained test plate by the same method as described above. The results are shown in Table 9-4-7. Table 5 and 7
As can be seen from the results shown in Tables and Tables 9,
The thermosetting powder coating composition of the present invention No. 89 has reduced static friction coefficient and critical surface tension without lowering weather resistance and acid resistance, and has water repellency and slipperiness comparable to those of polytetrafluoroethylene coating film. Thermosetting fluororesin-based powder that has excellent properties and excellent adhesion and impact resistance after boiling water test on stainless steel materials, so-called secondary adhesion of coating film and excellent secondary physical properties It is understood to be a coating composition. On the other hand, the compositions of Comparative Examples 1, 4, 6 and 10 containing no wax were poor in slipperiness and water repellency, and Comparative Examples 17 and 22 containing a small amount of wax.
The composition (1) is inferior in both slipperiness and water repellency. Further, Comparative Example 2 containing a large amount of wax is inferior in smoothness and impact resistance. On the other hand, the compositions of Comparative Examples 7, 11, 15, 19 and 20 in which neither the compound having a coupling group nor the epoxy resin was blended as the component (d) had poor adhesion and impact resistance. Similarly, the composition of Comparative Example 12 containing a small amount of the epoxy resin as the component (d) also has poor adhesion and impact resistance. On the contrary, the compositions of Comparative Examples 5, 13, and 23 containing a large amount of the epoxy resin as the component (d) were inferior in weather resistance and smoothness, and were inferior in impact resistance except Comparative Example 13. There is. Further, the composition of Comparative Example 8 in which the compound having the coupling group as the component (d) is small in the compounding amount is inferior in adhesiveness and impact resistance. vice versa,
The compositions of Comparative Examples 9 and 18 in which the compound having the coupling group as the component (d) was used in a large amount were inferior in smoothness. Furthermore, the composition of Comparative Example 14 in which the thermosetting powder coating resin having a crosslinkable reactive group was blended in an amount of more than 50% by weight of the fluororesin as the component (a), the weather resistance, the adhesion and the impact resistance were obtained. The compositions of Comparative Examples 16 and 21 in which the resin for thermoplastic powder coating is blended in an amount of more than 50% by weight of the fluororesin as the component (a) are inferior in weather resistance and smoothness. Comparative Example 3 using the polytetrafluoroethylene resin is inferior in adhesion and impact resistance.

[0063]

The thermosetting powder coating composition of the present invention is comparable to a coating film made of a polytetrafluoroethylene resin which is a thermoplastic fluororesin while maintaining a high degree of weather resistance, acid resistance and adhesion. A coating film having water repellency and slipperiness is formed. Furthermore, it is industrially useful for forming a coating film excellent in adhesion and impact resistance on a stainless steel material without chemical pretreatment or primer coating.

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Claims (11)

[Claims] 1. A fluororesin having a crosslinkable reactive group having a fluorine content of 10% by weight or more and a glass transition temperature of 35 to 120 ° C., and (b) the fluororesin. 0.01 to 10 parts by weight of (c) synthetic wax or natural wax, relative to 100 parts by weight of a resin composition consisting of 3 to 40% by weight of a curing agent capable of reacting with a crosslinkable reactive group to form a crosslink. (D) A thermosetting powder coating composition comprising 0.001 to 1.5 parts by weight of a compound having a coupling group and / or 0.01 to 5.0 parts by weight of an epoxy resin. 2. The thermosetting powder coating composition according to claim 1, wherein the weight loss on heating of the fluororesin having a crosslinkable reactive group is 2% by weight or less. 3. The hydroxyl value of component (a) is from 1 to 200 mg KOH.
/ G, The thermosetting powder coating composition according to claim 1 or 2. 4. The acid value of component (a) is from 1 to 200 mg KOH / g.
The thermosetting powder coating composition according to claim 1 or 2. 5. The epoxy equivalent of component (a) is 100-1.
The thermosetting powder coating composition according to claim 1 or 2, which has an amount of 5000 g / eq. 6. The thermosetting powder coating composition according to claim 1, wherein the melting point of the component (c) is 50 to 280 ° C. 7. The thermosetting powder coating composition according to claim 1, wherein the epoxy resin as the component (d) has a number average molecular weight of 350 to 50,000 and a softening point of 170 ° C. or lower. 8. The thermosetting resin composition according to claim 1, wherein 50% by weight or less of the compounding amount of the fluororesin as the component (a) is replaced with a thermosetting powder coating resin having a crosslinkable reactive group. Powder coating composition. 9. A thermosetting powder coating resin, wherein the resin is a hydroxyl group, an acid number, an epoxy equivalent, or a polyester resin or acryl having a crosslinkable reactive group corresponding to two or three of them. The thermosetting powder coating composition according to claim 8, which is a resin. 10. The compounding amount of the fluororesin of component (a) is 50.
2. A thermoplastic resin is used to replace less than or equal to wt%.
To 7. The thermosetting powder coating composition described in 7 above. 11. The thermosetting powder coating composition according to claim 10, wherein the thermoplastic resin is an acrylic resin, a polyester resin, a nylon resin or a fluororesin.