JP2000169759A - Novel resin composition for polyester-based powder coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make formable a coating film excellent in durability, acid resistance, external appearance and weathering resistance by incorporating a polyester resin bearing at least one silyl group at the end of a molecular chain in a specific ratio. SOLUTION: The resin composition for powder coating comprises as an essential component a polyester resin (A) bearing at least one silyl group represented by the formula at the end of the molecular chain. The component A bears the silyl group of the formula as a main crosslinkable group, has a glass transition temperature of 40-100 deg.C and a number average mol.wt. of 2,000-20,000 and forms at least 30 wt.% of all the crosslinkable polymers. In the formula, R1 is a 1-10C alkyl, 6-10C aryl or 7-10C aralkyl; X is H, a halogen, hydroxyl, alkoxyl or the like; and a is an integer of 0-2. This composition comprises 0.001-10 pts. by wt. of a curing catalyst based on 100 pts. by wt. of the component A. As the curing catalyst is employed, for example, an organic sulfonic acid, an organic metal compound or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin composition for powder coatings. For example, for example, automotive parts, industrial machinery, steel furniture, building interior and exterior, relates to a resin composition for powder coating suitably used for home appliances, and more specifically, durability, acid resistance, appearance, The present invention relates to a resin composition for powder coatings having excellent thermosetting properties and weather resistance.

[0002]

2. Description of the Related Art Compared to conventional solvent-based paints, powder paints are non-polluting paints, can be used immediately after painting, do not require multiple layers of coating, and are relatively inexpensive. It has been recognized that it has the advantage of being able to recover and reuse the surplus during painting, and has recently been used as a protective decorative paint for automotive parts, industrial machinery, steel furniture, building interior and exterior, and home appliances. Increasing demand. Various powder coatings such as polyester, epoxy, and acrylic are known as powder coatings, and polyester coatings are generally widely used because a coating film having a good balance of physical properties can be obtained. In recent years, the application range of powder coating materials has been expanded, and the use thereof outdoors has been increased. Therefore, needs for weather resistance have been increasing in addition to the conventional performance. However, with conventional polyester resins, the weather resistance is not always at a satisfactory level. To improve the weather resistance, a method using a polyester resin mainly composed of terephthalic acid, isophthalic acid and neopentyl glycol has been proposed.However, since it is cross-linked and cured by acid-epoxy cross-linking or urethane cross-linking, long-term exposure is required. , There is a problem that the weather resistance is reduced.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a polyester which has been frequently used in the prior art by acid-epoxy crosslinking or urethane crosslinking. An object of the present invention is to provide a new crosslinked polyester powder coating which overcomes the drawbacks of the powder coating and has excellent durability, acid resistance, appearance, and weather resistance. By using the method of the present invention, it is possible to obtain a coating film having weather resistance, which was not realized by a conventional polyester resin, and excellent in both acid resistance and appearance.

[0004]

SUMMARY OF THE INVENTION The present invention provides a novel resin composition having the following constitution, thereby achieving the above object. 1) A polyester resin (A) having at least one silyl group represented by the following general formula (1) at a molecular chain terminal is an essential component, and the component (A) is a silyl represented by the following general formula (1). Group as a main crosslinkable group, having a glass transition temperature of 40 to 100 ° C. and a number average molecular weight of 2,000 to 2,000
0, and 3 of the total polymer in which the component (A) is crosslinkable.
A resin composition for powder coatings, which is 0% by weight or more.

[0005]

Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
And at least one group selected from the group consisting of an aryl group having 10 to 10 and an aralkyl group having 7 to 10 carbon atoms, and when there are a plurality of groups, they may be the same or different. X ¹ is a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a phenoxy group, a thioalkoxy group, an acyloxy group, an aminoxy group, a ketoximate group, an amino group,
It is at least one group selected from the group consisting of an amide group and an alkenyloxy group. In the case of a plurality of groups, they may be the same or different. a is an integer of 0 to 2. 2) The resin composition for powder coating according to 1), wherein X in the general formula (1) is an alkoxy group. 3) When the silyl group of the general formula (1) is a trimethoxysilyl group, a triethoxysilyl group, a tripropoxysilyl group, a tributoxysilyl group, a methyldimethoxysilyl group, a methyldiethoxysilyl group, a methyldipropoxysilyl group, The resin composition for a powder coating according to 1) or 2), which is at least one selected from the group consisting of methyldibutoxysilyl groups or a mixture of two or more thereof. 4) The component (A) has both a silyl group and a carboxyl group represented by the general formula (1) (referred to as component A-1).
The resin composition for a powder coating according to any one of 1) to 3), characterized in that: 5) The component according to any one of 1) to 3), wherein the component (A) has both a silyl group represented by the general formula (1) and a hydroxyl group (referred to as component A-2). Resin composition for powder coating. 6) The component (A) wherein the component (A) is a polyester resin having a silyl group represented by the general formula (1) at both ends of a molecular chain (referred to as component A-3). The resin composition for a powder coating according to any one of the preceding claims. 7) The powder coating according to any one of 1) to 3), wherein the component (A) is a mixture of two or more of A-1, A-2, and A-3. Resin composition. 8) The composition according to any one of 1) to 7), wherein the composition contains 0.001 to 10 parts by weight of a curing catalyst (B) based on 100 parts by weight of the component (A). The resin composition for powder coating according to the above. 9) The component (B) is at least one selected from the group consisting of an organic acidic compound, a mixture or a reaction product of the organic acidic compound and a nitrogen-containing compound, and an organic metal compound, or a mixture of two or more types. The resin composition for a powder coating according to any one of 1) to 8), which is characterized in that: 10) at least one selected from the group consisting of an organic sulfonic acid and a mixture of an organic sulfonic acid and a nitrogen-containing compound, wherein the organic acidic compound as the component (B), and the mixture or reaction product of the organic acidic compound and the nitrogen-containing compound; The resin composition for a powder coating according to any one of 1) to 9), wherein the resin composition is a seed or a mixture of two or more kinds. 11) The organic metal compound of the component (B) is at least one selected from the group consisting of an organotin compound, an organic titanium compound, an organic aluminum compound, and an organic zirconium compound, or a mixture of two or more thereof. The resin composition for a powder coating according to any one of 1) to 10). 12) The resin composition for a powder coating contains a polyester resin (C) component having no carboxyl group and / or hydroxyl group, which does not contain a silyl group represented by the general formula (1). The resin composition for a powder coating material according to any one of)) to 11). 13) The compound according to any one of 1) to 12), wherein a compound (D) having a functional group capable of reacting with the carboxyl group and hydroxyl group is blended with the resin composition for powder coating. Resin composition for powder coating. 14) With respect to 100 parts by weight of the component (A), the component (C)
Characterized by containing 10 to 200 parts by weight of the component 1)
The resin composition for powder coatings according to any one of claims 13 to 13. 15) With respect to 100 parts by weight of the component (A), the component (D)
1) to 1 characterized by containing 1 to 50 parts by weight of a component
The resin composition for powder coating according to any one of 4). 16) wherein the component (D) is one or more selected from the group consisting of a compound having an epoxy group, a compound having a blocked isocyanate group, and a compound having a uretdione structure; The resin composition for a powder coating according to any one of the preceding claims. 17) The compound having an epoxy group as the component (D) is triglycidyl isocyanurate, tetraglycidyldiaminodiphenylmethane, glycidyl hexahydrophthalate, glycidyl dimer, epoxidized polybutadiene, epoxidized soybean oil, 3,4-epoxy -6-methylcyclohexylmethylcarboxylate, 3,4-epoxycyclohexylmethylcarboxylate, bisphenol epoxy resin, at least one selected from the group consisting of novolak epoxy resins,
Or a mixture of two or more kinds 1) to
16) The resin composition for a powder coating according to any one of the above 16). 18) The component (D) having a blocked isocyanate group-containing compound and / or a compound having a uretdione structure is obtained by converting isophorone diisocyanate and / or hexyl diisocyanate to ε-caprolactam, methyl ethyl ketone oxime, 1,2-pyrazole, 1,2,4-
At least one selected from the group consisting of triazole, diisopropylamine, 3,5-dimethylpyrazole, blocked isocyanate obtained by reaction with diethyl malonate, a compound having a uretdione structure represented by the following general formula (2), or The resin composition for a powder coating according to any one of 1) to 17), which is a mixture of two or more kinds.

[0006]

Embedded image (Wherein, R ² is an alkylene group having 4 to 12 carbon atoms, isophorone group, R ³ is an alkylene group having 2 to 18 carbon atoms, n is 1
Is an integer of up to 30. The method for producing the component (A) is not particularly limited. For example, a isocyanate containing a silyl group represented by the general formula (1) using a polyester resin having a carboxyl group and / or a hydroxyl group at a molecular chain terminal. A method of reacting a compound, using a polyester resin having a hydroxyl group at a molecular chain terminal, converting the compound into a polyester resin having an alkenyl group at a terminal, and subjecting a silane compound having a silyl group represented by the general formula (1) to a hydrosilylation reaction. It may be produced by a method of introducing, a method of synthesizing a polyester resin having an alkenyl group at a molecular chain terminal, and introducing a silane compound having a silyl group represented by the general formula (1) by a hydrosilylation reaction.

The polyester resin having a carboxyl group and / or a hydroxyl group is not particularly limited, but is preferably a resin mainly composed of terephthalic acid and / or isophthalic acid and neopentyl glycol from the viewpoint of weather resistance. Specific examples of polyvalent carboxylic acids include, for example, terephthalic acid,
Isophthalic acid, phthalic acid, methylphthalic acid, methylterephthalic acid, trimellitic acid, pyromellitic acid, hemi-mellitic acid, benzophenone-3,3 ', 4,4'-tetracarboxylic acid, adipic acid, suberic acid, azelaic acid,
Sebacic acid, succinic acid, maleic acid, fumaric acid, 2,6
-Naphthalenedicarboxylic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,2,3-propanetricarboxylic acid, 6
And polycarboxylic acids such as -methylcyclohex-4-ene-1,2,3-tricarboxylic acid, acid anhydrides thereof, and mixtures of two or more thereof. If necessary, a monobasic acid such as benzoic acid or p-tert-butylbenzoic acid as a molecular weight modifier may be used in combination.

Specific examples of polyhydric alcohols include, for example, ethylene glycol, propylene glycol, 1,
3-butanediol, 1,4-butanediol, 1,6
-Hexanediol, isopentyl glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, bishydroxyethyl terephthalate, hydrogenated bisphenol A, ethylene oxide adduct or propylene oxide adduct of hydrogenated bisphenol A, trimethylolethane, trimethylol Propane, trimethyloloctane, glycerin, erythritol, pentaerythritol, 2,2,4-trimethylpentane-1,3-
Examples thereof include diol, cyclohexanediol, and a mixture of two or more thereof.

The method for producing the polyester resin includes known methods, for example, methods such as an esterification reaction and a transesterification reaction. The isocyanate compound used for introducing the silyl group represented by the general formula (1) into the polyester resin is not particularly limited as long as it has both the silyl group represented by the general formula (1) and the isocyanate group. 2-isocyanatoethyltrimethoxysilane, 2-isocyanatoethylmethyldimethoxysilane, 2-isocyanatoethyltriethoxysilane, 2
-Isocyanatoethylmethyldiethoxysilane, 3-
Isocyanate propyl trimethoxy silane, 3-isocyanate propyl methyl dimethoxy silane, 3-isocyanate propyl triethoxy silane, 3-isocyanate propyl methyl diethoxy silane, and the like. The method for introducing the silyl group represented by the general formula (1) via the alkenyl group-containing polyester resin is not particularly limited, but a hydrosilylation reaction is used from the viewpoint of reaction efficiency and easiness. The method is preferred.

The silane compound used in the hydrosilylation reaction is not particularly limited. For example, trimethoxysilane, methyldimethoxysilane, triethoxysilane, methyldiethoxysilane, tris (methoxymethoxy) silane, methyl-bis (methoxy) And alkoxysilanes such as methoxy) -silane, tris (methoxyethoxy) silane and methyl-bis (methoxyethoxy) -silane. Examples of the hydrosilylation catalyst include a simple substance of platinum, alumina, silica, carbon black, and the like, on which solid platinum is supported, chloroplatinic acid, a complex of chloroplatinic acid with alcohol, aldehyde, ketone, etc., a platinum-olefin complex platinum - vinylsiloxane complex, a platinum - phosphine complex, a platinum - phosphite complex, dicarbonyl dichloroplatinum, platinum catalysts such as platinum _{alcoholate, Rh (PPh 3), RhCl} 3, RhAl 2 O 3, Ru
Cl ₃ , IrCl ₃ , FeCl ₃ , AlCl ₃ , PdCl ₂
2H ₂ O, NiCl ₂ , TiCl _4, etc., and these catalysts may be used alone or in combination of two or more.

The method of introducing an alkenyl group into the hydroxyl-terminated polyester resin is not particularly limited, and is an alkenyl group-containing isocyanate such as allyl isocyanate, 2-isocyanatoethyl (meth) acrylate, or 3-isocyanatopropyl (meth) acrylate. Compound,
Allyl bromide, allyl chloride, 4-bromo-1
-Butene, 4-chloro-1-butene, 6-bromo-1-
Hexene, 6-chloro-1-hexene, 8-bromo-1
And alkenyl group-containing halogen compounds such as 8-octene and 8-chloro-1-octene, and acid halides such as acrylic acid bromide and acrylic acid chloride.

In the synthesis of the polyester resin, the method of introducing an allyl group into the terminal includes allyl acetic acid,
Alkenyl group-containing monobasic acids such as (meth) acrylic acid, 2-butenoic acid and 3-butenoic acid, vinyl alcohol,
Allyl alcohol, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 6-hepten-1-ol, 7-octen-1-ol, 8-
Nonen-1-ol, 9-decene-1-ol, 2-
Examples include a method using an alkenyl group-containing monoalcohol such as (allyloxy) ethanol and neopentyl glycol monoallyl ether.

The component (A) has at least one silyl group represented by the general formula (1) in one molecule, and has a carboxyl group in addition to the silyl group (component A-1). The component (A-2) having both hydroxyl groups and the component (A-3) having a silyl group introduced at both terminals can be mentioned. These A-1, A-2, and A-3 components can be used as a mixture of two or more.

The component (A) has a silyl group represented by the general formula (1) as a main crosslinkable group. (A)
In the copolymer of the components, the number of silyl groups is preferably 50% or more based on the total number of crosslinkable groups.
%, More preferably at least 80%.

The number average molecular weight of the component (A) is from 2000 to 2000.
20,000, and preferably in the range of 3,000 to 10,000. When the molecular weight is less than 2,000, it becomes difficult for the coating film to exhibit sufficient mechanical physical properties.
If it exceeds 000, there is a problem that the smoothness of the coating film is inferior.

Further, the glass transition temperature of the component (A) is as follows:
It is 40-100 degreeC, Preferably it is 50-80 degreeC. When the temperature is lower than 40 ° C., the storage stability of the powder coating material is poor. On the other hand, when the temperature is higher than 100 ° C., the smoothness of the coating film is poor. The component (A) forms a siloxane bond by the action of moisture and can be crosslinked and cured. In the present invention, only the component (A) may be used as a crosslinkable and curable polymer. In addition, other crosslinkable and curable polymers (including homopolymers and copolymers. In addition, as a crosslinkable group,
(Including a silyl group, an epoxy group, and a hydroxyl group), for example, an epoxy resin, a polyester resin, an acrylic resin, a silicone resin, and the like. When another crosslinkable curable polymer is used in combination, the component (A) is preferably used in an amount of 30% by weight or more, preferably 40% by weight, and more preferably 50% by weight of the entire crosslinkable curable polymer (including the component (A)). % By weight, more preferably 70% by weight or more.

Examples of the curing catalyst of the component (B) include organic sulfonic acids, mixtures or reactants of organic sulfonic acids and nitrogen-containing compounds, phosphoric acid or phosphoric acid esters, and organometallic compounds. These may be used in combination of two or more.

Specific examples of the curing catalyst (B) include organic sulfonic acid compounds such as dodecylbenzenesulfonic acid, p-toluenesulfonic acid, 1-naphthalenesulfonic acid and 2-naphthalenesulfonic acid; And a nitrogen-containing compound (for example, 1-amino-2-
Propanol, monoethanolamine, diethanolamine, 2- (methylamino) ethanol, 2-dimethylethanolamine, 2-amino-2-methyl-1-propanol, diisopropanolamine, 3-aminopropanol, 2-methylamino-2- Mixtures or reactants with methylpropanol, morpholine, oxazolidine, 4,4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine, etc .; phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, mono Phosphoric acid or phosphate such as dodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didodecyl phosphate; propylene Kisaido, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidyl ether, 3
-Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethyldimethoxysilane, hexylamine, di-2-ethylhexylamine, N, N-dimethyldodecylamine, DABCO, DBU , Morpholine, diisopropanolamine and other amines; reactants of these amines with acidic phosphate esters; alkaline compounds such as sodium hydroxide and potassium hydroxide; benzyltriethylammonium chloride or bromide, tetrabutylammonium chloride or bromide Quaternary ammonium salts such as, for example, phosphonium salts; divalent tin compounds such as tin octylate and tin stearate, dibutyltin dioctoate, dibutyltin dilaurate,
Dibutyltin compounds such as dibutyltin diacetate, dibutyltin diacetylacetonate, dibutyltin bistriethoxysilicate, dibutyltin distearate, dibutyltin malate, dioctyltin diversate, dioctyltin dilaurate, dioctyltin distearate, and dioctyl such as dioctyltin malate Tetravalent organic tin compounds such as tin compounds; organic titanate compounds such as tetrastearyloxytitanium and tetramethoxytitanium; organic aluminum compounds such as isopropoxyaluminum and aluminum acetylacetonate; organic compounds such as zirconia stearylate and zirconium tetraacetylacetonate Zirconium compounds and the like can be mentioned.

Of these, organic titanate compounds and organic zirconium compounds are preferred from the viewpoint of curability during baking.

These curing catalysts may be used alone or in combination.

The amount of these curing catalysts used is (A) Component 1
0.001 to 10 parts by weight, preferably 0.01 to 8 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight.
Used by weight. If the amount is less than 0.001 part by weight, the curability is inferior.

As the other crosslinkable polymer, a silyl group represented by the general formula (1) may be used in view of compatibility with the component (A) and characteristics of a coating film obtained from the mixture. It is preferable to use a polyester resin (C) component containing no carboxyl group and / or hydroxyl group. The amount of the component (C) used is 10
The amount is preferably from 10 to 200 parts by weight, more preferably from 20 to 150 parts by weight, based on 0 parts by weight.

Also, the number average molecular weight of the component (C),
The glass transition temperature is not particularly limited, but from the viewpoint of weather resistance, acid resistance, and appearance of the coating film, the number average molecular weight is 2,000 to 20,
000, preferably in the range of 3000-10000, the glass transition temperature is 40-100 ℃,
Preferably it is 50-80 degreeC.

The component (D) is a compound having a functional group capable of reacting with a carboxyl group or a hydroxyl group in the component (A) or the component (C).

The component (D) includes a compound having an epoxy group and / or a compound having a blocked isocyanate group and / or a compound having a uretdione structure.

The compound having an epoxy group is not particularly limited, but is preferably a compound having two or more epoxy groups in one molecule from the viewpoint of physical properties of the coating film. As specific examples, for example, triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, glycidyl hexahydrophthalate, glycidyl dimer,
Epoxidized polybutadiene, epoxidized soybean oil, 3,4
-Epoxy-6-methylcyclohexylmethylcarboxylate, 3,4-epoxycyclohexylmethylcarboxylate, bisphenol-type epoxy resin, novolak-type epoxy resin, and the like.

The compound having a blocked isocyanate group and / or a uretdione structure is not particularly limited, but from the viewpoint of physical properties of a coating film, a compound having two or more blocked isocyanate groups and / or a uretdione structure in one molecule is preferable. preferable. As a specific example, for example,
(Poly) isocyanate such as isophorone diisocyanate, trimethylhexamethylene diisocyanate, hexyl diisocyanate, isophorone diisocyanate and / or hexyl diisocyanate are converted to ε-caprolactam, methyl ethyl ketone oxime, 1,2-pyrazole, 1,2,4-triazole, diisopropylamine, 3 , 5-dimethylpyrazole, blocked isocyanate obtained by reaction with diethyl malonate, a compound having a uretdione structure represented by the general formula (2), and the like.

The component (D) is the same as the component (A) 100
It is preferably used in an amount of 1 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on parts by weight.
The ratio of the crosslinkable functional group contained in the component (A) and / or the component (C) and the component (D) is based on 1 mol of the functional group in the component (A) and / or the component (C). The functional group in the component (D) is used in an amount of 0.5 to 1.7 mol, preferably 0.7 to 1.5 mol, more preferably 0.8 to 1.3 mol. When the ratio of the crosslinkable functional group is below the lower limit, the amount of crosslinking becomes insufficient, and the weather resistance, acid resistance, and curability are inferior. When the ratio exceeds the upper limit, the smoothness and storage stability are reduced.

The resin composition for powder coatings may contain, if necessary, resins such as polyester, epoxy and acrylic, inorganic pigments such as titanium dioxide, carbon black, iron oxide and chromium oxide, and phthalocyanine-based and quinacdrine-based resins. Additives such as organic pigments, coloring aids, spreading agents and defoamers, ultraviolet absorbers, antistatic agents and antiblocking agents can be added. The mixing ratio of these additives can be appropriately selected according to the required characteristics, and they can be used as a mixture.

The production of the powder coating is performed, for example, by using a heating roll,
It is prepared by using a melt kneader such as a kneader, melting and kneading the resin composition for a powder coating of the present invention containing the above additives as necessary, cooling, and then pulverizing.

The powder coating obtained in this manner is applied to a substrate by a known method such as electrostatic coating or fluid immersion coating. The thickness of the coating film can be appropriately selected as needed, and is usually 20 to 200 μm, preferably 40 to 150 μm.
μm is good. When the thickness is less than 20 μm, the coating film tends to be uneven, and when the thickness is more than 200 μm, there is a problem that the coating film tends to have irregularities.

The obtained coated product is usually at 150 to 220 ° C.
By baking at a temperature of about 5 minutes to 1 hour, it can be sufficiently cured, and a cured product (coating film) having excellent physical properties such as weather resistance and acid resistance can be formed. Fifteen
If the temperature is lower than 0 ° C or shorter than 5 minutes, the coating film is not sufficiently cured. If the temperature is higher than 220 ° C or longer than 1 hour, workability deteriorates and costs such as utility costs increase. Problem arises.

The composition of the present invention is used, for example, for building interiors and exteriors such as aluminum siding and fences, road materials such as guardrails, and home appliances such as air conditioners and refrigerators.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In addition, the part shown below shall show a weight part unless there is particular notice. Further, the characteristic values and the performance of the coating film in the examples were measured or evaluated by the following methods. Characteristic values (1) Hydroxyl value 3 g of a polyester resin and 0.6 ml of acetic anhydride were added to 50 ml of pyridine to perform acetylation, and then titrated with a 0.5N methanolic potassium hydroxide solution. (2) Acid value 1 g of polyester resin is dissolved in 50 ml of dioxane,
It was determined by titration with a 0.1N methanol solution of carylhydroxide. (3) Number average molecular weight of polymer Measured by gel permeation chromatography (GPC). Using a Waters 600 GPC system, chloroform was used as the mobile phase and the flow rate was 1 m.
L / min. The column temperature was measured at 40 ° C. The number average molecular weight was calculated using polystyrene as a standard sample. (4) Glass transition temperature Differential scanning calorimeter (DSC, DSC- manufactured by Shimadzu Corporation)
50 type) under a nitrogen atmosphere at a heating rate of 5 ° C./mi.
n and determined. Performance of coating film (1) Appearance Specular gloss (reflection at 60 °) was measured based on JIS K5400 and used as an index of appearance. ：: extremely good, ：: good, Δ: gloss, ×: poor (2) Weather resistance The appearance of the coating film after 1500 hours of irradiation with a sunshine weather meter was visually evaluated. ：: gloss retention of 85% or more, ：: 84 to 70%, Δ: 6
9 to 50%, x: 50% or less (3) Acid resistance The coating film appearance after immersing the coating film in a 5% aqueous sulfuric acid solution at room temperature for 24 hours was visually evaluated. ◎: extremely good, ○: slightly glossy, Δ: glossy,
×: cracking, peeling (4) Curability 1 g of the baked composition was wrapped in a 200-mesh stainless steel wire gauze, immersed in acetone for 24 hours, and the weight change of the composition was examined. 1
00%. ◎: 90% or more, ：: 90 to 80%, Δ: 80 to 70
%, ×: 70% or less (5) Storage stability For powder coatings stored at 40 ° C. for one month, the change in gel fraction before and after storage was examined as a measure of the progress of gelation. ◎: no change, ：: change in gel fraction within 5%, Δ: 5%
Gel fraction change of １５15%, ×: Gel fraction change of 15% or more Resin Production Example 1 40 parts of terephthalic acid, 8 parts of isophthalic acid, 36 parts of neopentyl glycol, 9 parts of ethylene glycol, 0.02 part of dibutyltin oxide Was charged into a reaction vessel, and the esterification reaction was carried out at 220 ° C. for 4 hours while gradually increasing the reaction temperature from 100 ° C. under a nitrogen stream while removing generated water. Then, once cooled to room temperature, 3-butene-1
7 parts of all were added, the temperature was raised again, and the esterification reaction was subsequently performed. The reactor was evacuated to remove water in the system, and purified to obtain an alkenyl-terminated polyester resin. 100 parts of the obtained polyester resin, 9 parts of triethoxysilane, 3 parts of methyl orthoformate, and 0.003 part of platinum bis (divinyltetramethyldisiloxane) were charged into a pressure-resistant reaction vessel and reacted at 100 ° C. for 4 hours. To obtain a vinyl copolymer having an alkoxysilyl group (resin (α-1)). The resin (α-1) had a number average molecular weight of 4000 and a glass transition temperature of 58 ° C. Resin Production Example 2 ER commercially available as polyester resin for powder coating
-6680 (manufactured by Nippon Ester Co., Ltd .; hydroxyl value 36 mg)
100 parts of (KOH / g) and 200 parts of toluene were charged into a reaction vessel, and heated to 100 ° C. while stirring under a nitrogen stream to dissolve the same. A mixture of 16 parts of 3-isocyanatopropyltriethoxysilane and 50 parts of toluene was added dropwise over 30 minutes, and thereafter, stirring was continued for 3 hours. By IR
After confirming the completion of the reaction and cooling to room temperature, toluene was distilled off under reduced pressure to obtain a vinyl copolymer having an alkoxysilyl group at both terminals (resin (α-2)). The resin (α-2) had a number average molecular weight of 3,600 and a glass transition temperature of 55 ° C. Resin Production Example 3 FineDick A-239-J (Dainippon Ink Chemical Co., Ltd.) commercially available as a polyester resin for powder coatings
Product; acid value 14 mgKOH / g, hydroxyl value 14 mgKOH
/ G) 100 parts and 200 parts of toluene were charged into a reaction vessel, and heated to 100 ° C. while stirring under a nitrogen stream to dissolve the same. A mixture of 8 parts of 3-isocyanatopropyltriethoxysilane and 50 parts of toluene was added dropwise over 30 minutes, and then stirring was continued for 3 hours. After confirming the completion of the reaction by IR and cooling to room temperature, toluene was distilled off under reduced pressure to obtain a polyester resin having a terminal alkoxysilyl group and a carboxyl group (resin (α-3)).
The acid value of the resin (α-3) was 14 mgKOH / g, the number average molecular weight was 4,100, and the glass transition temperature was 60 ° C. Resin Production Example 4 ER commercially available as polyester resin for powder coating
-6680 (manufactured by Nippon Ester Co., Ltd .; hydroxyl value 36 mg)
100 parts of (KOH / g) and 200 parts of toluene were charged into a reaction vessel, and heated to 100 ° C. while stirring under a nitrogen stream to dissolve the same. A mixture of 8 parts of 3-isocyanatopropyltriethoxysilane and 50 parts of toluene was added dropwise over 30 minutes, and then stirring was continued for 3 hours. After confirming the completion of the reaction by IR and cooling to room temperature, toluene was distilled off under reduced pressure to obtain a vinyl copolymer having a terminal alkoxysilyl group and hydroxyl group (resin (α-4)). . The resin (α-4) had a hydroxyl value of 17 mgKOH / g, a number average molecular weight of 3,300 and a glass transition temperature of 59 ° C. Examples 1 to 11 Using resins (α-1) to (α-4), according to the formulation (shown in parts) in Table 1, all components were drive-rendered (trade name, manufactured by Mitsui Chemicals, Inc.) Henschel mixer), melt-kneaded using an extrusion kneader (BUSS Co-Kneader PCS-30, manufactured by BUSS) under a temperature condition of 110 to 120 ° C., cooled, and then jet crushed. (Single Enterprise Jet Co., Ltd., trade name: single track jet mill STJ200), finely pulverized, and powder coating (γ-1) having an average particle size of 30 μm
(Γ-11) was produced. The obtained powder coating is coated to a thickness of 0.
Film thickness of 50-60μm on 8mm zinc phosphate treated steel plate
Become an electrostatic coating machine (made by Nippon Wagner Spray Tech Co., Ltd., trade name Airmatic Spray Gun PE
It was applied using M-C1) and baked at 180 ° C. for 20 minutes to form a coating film. The results of evaluating the performance of the obtained coating film are shown in Table 1.

[0035]

[Table 1] (In the table, ER-8107 is a carboxyl group-terminated polyester resin manufactured by Nippon Ester Co., Ltd. (acid value 33 mg KOH /
g), ER-6680 is a hydroxyl-terminated polyester resin manufactured by Nippon Ester Co., Ltd. (hydroxyl value 36 mgKOH / g)
MBTO is monobutyltin oxide, TGIC is triglycidyl isocyanurate, B1530 is Block Isocyanate VES manufactured by Daicel Huls Co., Ltd.
TAGON B 1530, TiO ₂ indicates titanium oxide CR-90 manufactured by Ishihara Sangyo Co., Ltd., and acronal (Acronal 4F) indicates an acrylate-based leveling agent manufactured by BASF. ) Comparative Examples 1 to 3 According to Table 2, powder coating (γ
-12) and (γ-13) were prepared. Table 2 shows the results of evaluation of the performance of the coating film obtained by coating in the same manner as in the examples.
It was shown to.

[0036]

[Table 2] (In the table, ER-8107 is a carboxyl group-terminated polyester resin manufactured by Nippon Ester Co., Ltd. (acid value 33 mg KOH /
g), ER-6680 is a hydroxyl-terminated polyester resin manufactured by Nippon Ester Co., Ltd. (hydroxyl value 36 mgKOH / g)
TGIC is triglycidyl isocyanurate, B
1530 Daicel-Huels Co., Ltd. manufactured blocked isocyanate VESTAGON B 1530, TiO ₂
Indicates titanium oxide CR-90 manufactured by Ishihara Sangyo Co., Ltd., and acronal (Acronal 4F) indicates an acrylate-based leveling agent manufactured by BASF. )

[0037]

According to the present invention, a resin composition for powder coatings having excellent durability, acid resistance, appearance, thermosetting properties and weather resistance can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C08G 18/79 C08G 18/79 A 18/80 18/80 59/42 59/42 63/695 63/695 F-term (for reference) 4J029 AA03 AB07 AC02 AD01 AD02 AD03 AD07 AE11 BA02 BA03 BA05 BA08 BA09 BA10 BD03A BD07A CA02 CA04 CA06 CB04A CB04B CB05A CB06A CC06A CD03 FC02 FC03 FC04 FC05 FC07 FC08 FC35 FC31 GA41 GA04 GA03 DA04 DF20 DF21 DF22 HA07 HC03 HC17 HC22 HC34 HC71 HC73 HD04 HD12 RA07 4J036 AB17 AD01 AF01 AG06 AH07 AK03 AK19 FB11 JA03 4J038 DB002 DD241 DD242 DG262 GA01 GA03 GA06 GA09 GA12 GA13 GA15 JC13 JC38 KA04 MA05 MA13 P14

Claims (18)

[Claims] An essential component is a polyester resin (A) having at least one silyl group represented by the following general formula (1) at a molecular chain terminal, wherein the component (A) is represented by the following general formula (1): The main group is a silyl group to be crosslinked, the glass transition temperature is 40 to 100 ° C, and the number average molecular weight is 20.
A resin composition for a powder coating, wherein the amount is from 0.000 to 20,000, and the component (A) accounts for 30% by weight or more of the entire crosslinkable polymer. Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
And at least one group selected from the group consisting of an aryl group having 10 to 10 and an aralkyl group having 7 to 10 carbon atoms, and when there are a plurality of groups, they may be the same or different. X ¹ is a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a phenoxy group, a thioalkoxy group, an acyloxy group, an aminoxy group, a ketoximate group, an amino group,
It is at least one group selected from the group consisting of an amide group and an alkenyloxy group. In the case of a plurality of groups, they may be the same or different. a is an integer of 0 to 2. ) 2. The resin composition according to claim 1, wherein X in the general formula (1) is an alkoxy group. 3. The silyl group of the general formula (1) is a trimethoxysilyl group, a triethoxysilyl group, a tripropoxysilyl group, a tributoxysilyl group, a methyldimethoxysilyl group, a methyldiethoxysilyl group, or a methyldipropoxy group. The resin composition for a powder coating according to claim 1 or 2, wherein the resin composition is at least one selected from the group consisting of a silyl group and a methyldibutoxysilyl group, or a mixture of two or more thereof. 4. The component (A) according to claim 1, wherein the component (A) has both a silyl group and a carboxyl group represented by the general formula (1) (referred to as component A-1). Item 10. The resin composition for a powder coating according to item 8. 5. The component (A) has both a silyl group represented by the general formula (1) and a hydroxyl group (referred to as component A-2).
The resin composition for a powder coating according to any one of claims 1 to 3, characterized in that: 6. The component (A) wherein the component (A) is a polyester resin having a silyl group represented by the general formula (1) at both ends of a molecular chain (referred to as component (A-3)). The resin composition for a powder coating according to any one of claims 1 to 3. 7. The composition according to claim 1, wherein the component (A) is A-1, A-2 or A-3.
A mixture of two or more of the following:
4. The resin composition for a powder coating according to any one of 3. 8. The composition according to claim 1, wherein the composition contains 0.001 to 10 parts by weight of the curing catalyst (B) based on 100 parts by weight of the component (A). Or 1
Item 10. The resin composition for a powder coating according to item 8. 9. The component (B) comprises an organic acidic compound, a mixture or a reaction product of the organic acidic compound and a nitrogen-containing compound,
At least one selected from the group consisting of organometallic compounds
The resin composition for a powder coating according to any one of claims 1 to 8, wherein the resin composition is a seed or a mixture of two or more kinds. 10. The organic acidic compound as the component (B), a mixture or a reaction product of the organic acidic compound and a nitrogen-containing compound, selected from the group consisting of organic sulfonic acids and a mixture of an organic sulfonic acid and a nitrogen-containing compound. At least one,
The resin composition for powder coating according to any one of claims 1 to 9, wherein the resin composition is a mixture of two or more kinds. 11. The organometallic compound as the component (B) is at least one selected from the group consisting of organotin compounds, organotitanium compounds, organoaluminum compounds, and organozirconium compounds, or a mixture of two or more thereof. The resin composition for a powder coating according to any one of claims 1 to 10, characterized in that: 12. The resin composition for a powder coating contains a polyester resin (C) having a carboxyl group and / or a hydroxyl group, which does not contain a silyl group represented by the general formula (1). Claims 1 to 11
The resin composition for powder coating according to any one of the above. 13. A compound (D) having a functional group capable of reacting with a carboxyl group or a hydroxyl group in the resin composition for powder coating.
The resin composition for powder coating according to any one of the above. 14. The powder coating composition according to claim 1, wherein the component (C) is contained in an amount of 10 to 200 parts by weight based on 100 parts by weight of the component (A). Resin composition. 15. The powder coating material according to claim 1, wherein the component (D) is contained in an amount of 1 to 50 parts by weight based on 100 parts by weight of the component (A). Resin composition. 16. The method according to claim 16, wherein the component (D) is at least one compound selected from the group consisting of compounds having an epoxy group, compounds having a blocked isocyanate group, and compounds having a uretdione structure. Item 1
The resin composition for a powder coating according to any one of claims 15 to 15. 17. The compound having an epoxy group as the component (D) is triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, glycidyl hexahydrophthalate, glycidyl dimer,
Epoxidized polybutadiene, epoxidized soybean oil, 3,4
-At least one selected from the group consisting of epoxy-6-methylcyclohexylmethylcarboxylate, 3,4-epoxycyclohexylmethylcarboxylate, bisphenol-type epoxy resin, and novolak-type epoxy resin, or a mixture of two or more thereof. The resin composition for a powder coating according to any one of claims 1 to 16, which is characterized by the following. 18. The method according to claim 18, wherein the blocked isocyanate group-containing compound and / or the compound having a uretdione structure as the component (D) is obtained by converting isophorone diisocyanate and / or hexyl diisocyanate to ε-caprolactam, methyl ethyl ketone oxime, 1,2-pyrazole,
2,4-triazole, diisopropylamine, 3,5
-At least one selected from the group consisting of dimethylpyrazole, blocked isocyanate obtained by reaction with diethyl malonate, and a compound having a uretdione structure represented by the following general formula (2), or a mixture of two or more types; The resin composition for a powder coating according to any one of claims 1 to 17, characterized in that: Embedded image (Wherein, R ² is an alkylene group having 4 to 12 carbon atoms, isophorone group, R ³ is an alkylene group having 2 to 18 carbon atoms, n is 1
Is an integer of up to 30 )