CN107849230B - Copolyester and metal primer coating using the same - Google Patents
Copolyester and metal primer coating using the same Download PDFInfo
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- CN107849230B CN107849230B CN201680040100.4A CN201680040100A CN107849230B CN 107849230 B CN107849230 B CN 107849230B CN 201680040100 A CN201680040100 A CN 201680040100A CN 107849230 B CN107849230 B CN 107849230B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/66—Polyesters containing oxygen in the form of ether groups
- C08G63/668—Polyesters containing oxygen in the form of ether groups derived from polycarboxylic acids and polyhydroxy compounds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
- C09D167/025—Polyesters derived from dicarboxylic acids and dihydroxy compounds containing polyether sequences
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/002—Priming paints
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Polyesters Or Polycarbonates (AREA)
- Paints Or Removers (AREA)
Abstract
The present application provides a copolyester effective as an adhesive component of a metal primer coating for coil coating. Further, a metal primer coating is provided which is a coating composition using the copolyester and is excellent in surface hardness, bendability, corrosion resistance and chemical resistance. A copolyester (A) comprising a polycarboxylic acid component and a polyol component as copolymerized components, wherein the aromatic dicarboxylic acid component is 95 to 100 mol% and the aliphatic dicarboxylic acid component is 0 to 5 mol% based on 100 mol% of the total polycarboxylic acid component; and a diol component having a specific structure is 1 to 30 mol% based on 100 mol% of the total polyol component; the glass transition temperature of the copolyester (A) is in the range of 25 to 50 ℃.
Description
Technical Field
The present invention relates to a copolyester and a metal primer coating using the same. More specifically, the present invention relates to a resin and a coating composition having excellent corrosion resistance and processability.
Background
The copolyester is widely used as a raw material for resin compositions such as coating agents, inks, and adhesives, and generally comprises a polycarboxylic acid and a polyhydric alcohol. Since flexibility and molecular weight can be freely controlled by selecting and combining polycarboxylic acid and polyol, they are widely used in various applications such as coating agent applications and adhesive applications.
Among them, in a precoated metal formed by applying a coating material containing a resin component onto a metal thin plate, a coating material using a high molecular weight copolyester excellent in coating film bendability is often used (for example, patent document 1). However, when a high-molecular-weight polyester is used as a coating material, the solution viscosity becomes very high and handling becomes difficult if the solid content concentration is high, while using a bisphenol a main chain polyol which is problematic in terms of health effects as an essential component. On the other hand, when the solid content concentration is reduced, it is difficult to increase the thickness of the coating film, and a large amount of solvent is also required, which causes economic and environmental problems.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 5-295239
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above problems of the prior art. That is, an object of the present invention is to provide a copolyester effective as a binder component to be mixed in a metal primer coating (metal undercoating coating), and further to provide a coating composition which can form a coating film having high hardness, corrosion resistance and chemical resistance while maintaining a low solution viscosity which is easy to handle even with a high solid content and having high bendability equivalent to that of a high molecular weight polyester.
Means for solving the problems
The present inventors have intensively studied and found that the above problems can be solved by the following means, and reached the present invention.
That is, the present invention is constituted as follows.
A copolyester (A) comprising a polycarboxylic acid component and a polyol component as copolymerized components, wherein the aromatic dicarboxylic acid component is 95 to 100 mol% and the aliphatic dicarboxylic acid component is 0 to 5 mol% based on 100 mol% of the total polycarboxylic acid component; and the diol component represented by the general formula (1) is 1 to 30 mol% based on 100 mol% of the total polyol component; the glass transition temperature of the copolyester (A) is in the range of 25 to 50 ℃,
[ solution 1]
In the general formula (1), n is an integer of 3 or more.
The copolyester (A) preferably has a number average molecular weight of 4000 to 9000. Further, it is preferable that the aliphatic dicarboxylic acid component is not contained.
The general formula (1) is preferably triethylene glycol.
A metallic primer coating comprising the copolyester (A), a crosslinking agent (B), a pigment (C), an additive (D) and an organic solvent (E).
A metal-coated plate having the above-described metal primer coating as a primer layer.
Effects of the invention
The metal primer coating using the copolyester of the present invention has a high solid content and a low solution viscosity, and exhibits high hardness, high bendability, high corrosion resistance, and excellent chemical resistance. Therefore, the primer layer is suitable for coil coating for household appliances or building materials.
Detailed Description
The present invention is described in detail below.
< copolyester (A) >
The metal primer coating using the copolyester (A) of the present invention exhibits excellent bendability, hardness, corrosion resistance and chemical resistance. Therefore, the primer is suitable for priming a metal steel sheet which requires deformation processing after coating. The product produced by using the copolyester (A) of the present invention can obtain a coating film having high hardness, high processability and high corrosion resistance.
The copolyester (A) of the present invention has a chemical structure obtainable by a polycondensate of a polycarboxylic acid component and a polyol component, and each of the polycarboxylic acid component and the polyol component is composed of 1 or 2 or more selected components.
In the copolyester (A) of the present invention, the polycarboxylic acid component is preferably a dicarboxylic acid, and more preferably an aromatic dicarboxylic acid. The copolymerization amount of the aromatic dicarboxylic acid is required to be 95 to 100 mol% with respect to all the dicarboxylic acid components. Preferably 98 mol% or more, and more preferably 100 mol%. If a dicarboxylic acid component other than the aromatic dicarboxylic acid component is contained in an amount of more than 5 mol% as a copolymerization component, the chemical resistance of the coating film may be reduced.
The aromatic dicarboxylic acid constituting the copolyester (A) of the present invention is not particularly limited, but terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, sodium 5-sulfoisophthalate, and the like can be used. Among them, terephthalic acid and isophthalic acid are preferable.
The aliphatic dicarboxylic acid constituting the copolyester (a) of the present invention is not particularly limited, but succinic acid, adipic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, tetrahydrophthalic acid, and the like can be used. Among them, sebacic acid is preferable. The copolymerization amount of the aliphatic dicarboxylic acid is preferably 5 mol% or less, more preferably 2 mol% or less, and still more preferably 0 mol% with respect to the total dicarboxylic acids. If the amount exceeds 5 mol%, the chemical resistance of the coating film may be reduced.
In the copolyester (A) of the present invention, the diol component represented by the general formula (1) must be copolymerized in an amount of 1 to 30 mol% based on the total polyol component.
[ solution 1]
In the general formula (1), n is an integer of 3 or more. Preferably 23 or less, more preferably 15 or less, still more preferably 5 or less, particularly preferably 4 or less, and most preferably 3. When n is less than 3, the flexibility of the coating film tends to be lowered. On the other hand, if n is too large, corrosion resistance may be reduced.
The diol component represented by the general formula (1) is not particularly limited, but may include triethylene glycol, tetraethylene glycol, pentaethylene glycol, polyethylene glycol (number average molecular weight 650), polyethylene glycol (number average molecular weight 1000), and the like. Among them, triethylene glycol is preferable from the viewpoint of a good balance between the amount of ester bonds and the amount of ether bonds contributing to adhesion with the coated steel sheet.
The copolymerization amount of the diol component represented by the general formula (1) is preferably 3 mol% or more, more preferably 5 mol% or more, based on 100 mol% of the total polyol component. Further, it is preferably 28 mol% or less, more preferably 25 mol% or less, and still more preferably 20 mol% or less. If the amount is too small, the glass transition temperature of the copolyester (A) may be high, and the bendability (processability) may be deteriorated. On the other hand, if the amount is too large, the glass transition temperature of the copolyester (A) may be too low, and the hardness or corrosion resistance may be lowered.
The polyol constituting the copolyester (A) of the present invention is preferably a diol component other than the diol component represented by the general formula (1). The diol component other than the diol component represented by the general formula (1) is not particularly limited, but aliphatic diol components such as ethylene glycol, 1, 2-propanediol, 1, 3-butanediol, 1, 2-butanediol, 1, 4-butanediol, 2-methyl-1, 3-propanediol, neopentyl glycol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, 1-methyl-1, 8-octanediol, 2-dimethyl-1, 3-propanediol, and 2-ethyl-2-butyl-1, 3-propanediol can be used, and 1 or 2 or more kinds thereof can be used. Further, alicyclic diol components such as 1, 4-cyclohexanedimethanol and tricyclodecanedimethanol, and polyalkylene ether glycol components such as polytetramethylene glycol and polypropylene glycol may also be used. Preferred are ethylene glycol, 1, 2-propylene glycol, 2-methyl-1, 3-propanediol, neopentyl glycol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, 2-ethyl-2-butyl-1, 3-propanediol, 1, 4-cyclohexanedimethanol.
The copolymerization amount of the aliphatic diol component other than the above general formula (1), the alicyclic diol component and the polyalkylene ether glycol component is preferably 70 to 99 mol% based on 100 mol% of all the polyol components. If the amount is too small, the glass transition temperature of the copolyester (A) may be too low, and the hardness or corrosion resistance may be lowered. On the other hand, if the amount is too large, the glass transition temperature of the copolyester (A) may be high, and the bendability (processability) may be lowered.
Further, a diol component having a bisphenol skeleton such as bisphenol a or bisphenol F is less preferable because it is considered to be an endocrine-disturbing substance. The copolymerization amount of the diol component having a bisphenol skeleton is preferably 5 mol% or less, more preferably 1 mol% or less, and still more preferably 0 mol% when the total polyol component is 100 mol%.
The glass transition temperature of the copolyester (A) of the present invention must be in the range of 25 to 50 ℃. By setting the glass transition temperature in the range of 25 to 50 ℃, corrosion resistance and bendability can be achieved at the same time. Preferably 30 to 48 ℃, and more preferably 35 to 45 ℃. If the glass transition temperature is less than 25 ℃, the corrosion resistance may be lowered. Further, when the glass transition temperature exceeds 50 ℃, the flexibility of the coating film tends to be lowered, which is not preferable.
The copolyester (A) of the present invention may contain a polycarboxylic acid component having a valence of 3 or more and/or a polyol component having a valence of 3 or more. Examples of the polycarboxylic acid component having a valence of 3 or more include aromatic carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and trimesic acid, and aliphatic carboxylic acids such as 1,2,3, 4-butane tetracarboxylic acid. Examples of the polyhydric alcohol component having a valence of 3 or more include glycerin, trimethylolpropane, trimethylolethane, neopentyltetraol, α -methylglucose, mannitol and sorbitol, and 1 or 2 or more kinds thereof can be used. The copolymerization amount of the polycarboxylic acid component having a valence of 3 or more is preferably 5 mol% or less, more preferably 2 mol% or less, further preferably 1 mol% or less, and may be 0 mol% when the total polycarboxylic acid component is 100 mol%. The copolymerization amount of the polyol component having a valence of 3 or more is preferably 2 mol% or less, more preferably 1 mol% or less, and may be 0 mol% when the total polyol component is 100 mol%. If too much, the copolyester (A) may gel during the polymerization.
The number average molecular weight of the copolyester (A) of the present invention is preferably 2000 or more, more preferably 4000 or more. Further, 9000 or less is preferable, 8000 or less is more preferable, and 7400 or less is particularly preferable. When the number average molecular weight is less than 2000, the flexibility of the coating film may be lowered, which is not preferable. On the other hand, if it exceeds 9000, the viscosity of the resulting coating material will be high, making handling difficult, which is not preferable.
The reduced viscosity of the copolyester (A) of the present invention is preferably 0.15dl/g or more, more preferably 0.18dl/g or more. Further, it is preferably not more than 0.35dl/g, more preferably not more than 0.32 dl/g. If the reduced viscosity is too low, the flexibility of the coating film may be reduced, and if it is too high, the viscosity when dissolved in an organic solvent may be too high, making handling difficult.
Examples of the polycondensation reaction for producing the copolyester (A) of the present invention include: 1) a method of heating a polycarboxylic acid and a polyhydric alcohol in the presence of an arbitrary catalyst to conduct a dehydro-esterification step to conduct a dehydro-polycondensation reaction, and 2) a method of heating an alcohol ester of a polycarboxylic acid and a polyhydric alcohol in the presence of an arbitrary catalyst to conduct a transesterification reaction to conduct a dehydro-polycondensation reaction. In the above methods 1) and 2), a part or all of the acid component may be replaced with an acid anhydride.
In the production of the copolyester (A) of the present invention, conventionally known polymerization catalysts can be used, for example, titanium compounds such as tetra-n-butyl titanate, tetra-isopropyl titanate and titanium oxyacetylacetonate, antimony compounds such as antimony trioxide and tributoxyantimony, germanium compounds such as germanium oxide and tetra-n-butoxygermanium, and acetates of magnesium, iron, zinc, manganese, cobalt, aluminum, etc. These catalysts may be used in a proportion of 1 kind, or 2 or more kinds in combination.
In the production of the copolyester (A) of the present invention, the resin acid value of the copolyester (A) may be increased for the purpose of improving the substrate adhesiveness and the crosslinking property. The acid value of the resin is preferably leq/106g or more, more preferably 3eq/106g or more, particularly preferably 5eq/106g is above. Further, it is preferably 200eq/106g or less, more preferably 100eq/106g or less, particularly preferably 50eq/106g or less, particularly preferably 40eq/106g or less, most preferably 30eq/106g is below. These effects can be expected by setting the resin acid value within the above range. If the acid value of the resin is too small, it may be difficult to improve the substrate adhesiveness and the crosslinkability, and if it is too large, the chemical resistance may be reduced although the substrate adhesiveness and the crosslinkability are improved, and thus it is not suitable for applications requiring durability.
Examples of the method for increasing the acid value of the copolyester (A) of the present invention include: (1) the method of adding a polycarboxylic acid and/or a polycarboxylic acid anhydride after the completion of the polycondensation reaction and reacting the resulting mixture, (2) the method of intentionally modifying the resin by allowing heat, oxygen, water or the like to act during the polycondensation reaction, and the like, and these methods can be optionally performed.
The copolyester (A) of the present invention can be used in a state of being dissolved in a known organic solvent. Examples of the known organic solvent that can be used include aromatic hydrocarbons such as toluene, xylene, and Solvesso (registered trademark), esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and dibasic ester (DBE), ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone, and ethers such as n-butyl cellosolve and t-butyl cellosolve, and they can be arbitrarily selected and mixed in consideration of solubility and evaporation rate (drying property). Among them, preferred are mixed solvents of aromatic hydrocarbons and ketones, and preferred are mixed solvents of Solvesso and cyclohexanone.
The polyester (a) of the present invention is preferably dissolved in the organic solvent at 25 ℃ at a concentration of 40% by mass or more, more preferably at a concentration of 50% by mass or more, and still more preferably at a concentration of 60% by mass or more. By adopting the above solubility, the solid content concentration of the metal primer coating can be increased, and the operation can be facilitated.
< crosslinking agent (B) >)
The copolyester (A) of the present invention may be used together with the crosslinking agent (B). The crosslinking agent (B) may be a known crosslinking agent. The crosslinking agent (B) is not particularly limited as long as it is a substance which causes a crosslinking reaction with the copolyester (A), and preferable examples thereof include isocyanate compounds, epoxy resins, amino resins (common name of alkyl etherified formaldehyde resins), phenol resins, and the like, and 1 or 2 or more kinds thereof can be arbitrarily selected.
The isocyanate compound is not particularly limited, and may be an aromatic, alicyclic or aliphatic polyisocyanate compound, and may be of a low molecular weight type or a high molecular weight type. Examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, or a trimer of these isocyanate compounds, and a terminal isocyanate compound obtained by reacting the above isocyanate compound with an active hydrogen compound such as ethylene glycol, trimethylolpropane, propylene glycol, glycerin, sorbitol, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, polyester polyols, polyether polyols, polyamides, and the like. These compounds may be used in a proportion of 1 species, or in a proportion of 2 or more species.
Further, when a blocked isocyanate compound is used as the isocyanate compound, the life of the metallic primer coating can be extended. Examples of the blocking agent for blocking the isocyanate compound include phenols such as phenol, thiophenol, tolylthiophenol, cresol, xylenol, resorcinol, nitrophenol and chlorophenol, oximes such as acetoxime, methylethylketoxime and cyclohexanone oxime, alcohols such as methanol, ethanol, propanol, butanol, t-butanol and t-amyl alcohol, lactams such as e-caprolactam, other aromatic amines, imides, active methylene compounds such as acetylacetone, acetoacetate and ethyl malonate, thiols, imines, and ureas. The blocked isocyanate compound is obtained by reacting the above isocyanate compound with a blocking agent according to a conventionally known method, and 1 kind or 2 or more kinds may be used in combination.
Examples of the epoxy resin include: glycidyl ethers of bisphenol A and oligomers thereof, diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl p-hydroxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene glycol diglycidyl ester, propylene glycol diglycidyl ester, 1, 4-butanediol diglycidyl ester, 1, 6-hexanediol diglycidyl ester, and polyalkylene glycol diglycidyl esters, triglycidyl trimellitate, triglycidyl isocyanurate, 1, 4-glycidoxybenzene, diglycidyl propyleneurea, glycerol triglycidyl ether, trimethylolethane glycidyl ether, trimethylolpropane diglycidyl ether, maleic anhydride, Trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, triglycidyl ether of a glycerin alkylene oxide adduct, and the like. These may be used in a proportion of 1 species, or in a proportion of 2 or more species.
The amino resin is not particularly limited, and examples thereof include methylolated amino resins obtained by the reaction of an amino component such as melamine, urea, benzoguanamine, methylguanamine, steroidal guanamine (steroguanamine), spiroguanamine (spiroguanamine), or dicyandiamide with an aldehyde component such as formaldehyde, trioxymethylene, acetaldehyde, or benzaldehyde. The methylol group of the methylolated amino resin is etherified with an alcohol having 1 to 6 carbon atoms. These may be used alone or in combination of 2 or more.
As the phenol resin, resol-type phenol resin can be used. Examples of the resol-type phenol resin include phenol resins obtained from phenol, m-cresol, m-methylphenol, 3, 5-xylenol, m-methoxyphenol, o-cresol, p-tert-butylphenol, p-ethylphenol, 2, 3-xylenol, 2, 5-xylenol, bisphenol a, bisphenol F and the like, and these resins may be used alone or in combination of 2 or more.
The crosslinking agent (B) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and further preferably 10 parts by mass or more, based on 100 parts by mass of the copolyester (a). Further, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less. If the amount is too small, the crosslinking of the coating film obtained from the metal primer coating material becomes insufficient, and the necessary hardness, firmness, and adhesive strength of the coating film may not be obtained. If the amount is too large, the flexibility of the coating film may be decreased.
In the present invention, a catalyst which contributes to the crosslinking reaction of the copolyester (A) and the crosslinking agent (B) may be further used. For example, as the acid catalyst, an organic sulfonic acid compound such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, camphorsulfonic acid, etc., a phosphoric acid compound, and an amine-neutralized product of these compounds can be used. As the base catalyst, an amine compound can be used. As the metal catalyst, organic acid salts, halide salts, nitrate salts, sulfate salts, organic complex compounds, and the like of various metals can be used. These catalysts may be used in combination of 1 or 2 or more in accordance with the curing behavior of the crosslinking agent (B).
< pigment (C) >
The copolyester (A) of the present invention can be used together with the pigment (C). Specific examples of the pigment (C) include, but are not particularly limited to, inorganic pigments such as titanium oxide, zinc oxide, zirconium oxide, calcium carbonate, barium sulfate, aluminum oxide, chromium oxide, chromate, kaolin, carbon black, iron oxide, talc, mica, zinc phosphate, iron phosphate, aluminum phosphate, zinc phosphite, aluminum tripolyphosphate, calcium molybdate, aluminum molybdate, barium molybdate, vanadium oxide, chromic acid, zinc chromate, calcium silicate, water-dispersible silica, and fumed silica, and organic pigments such as phthalocyanine blue, phthalocyanine green, carbazole dioxazine violet, anthrapyrimidine yellow, isoindoline yellow, and indanthrene blue. By adding 1 or 2 or more of these substances, effects of coloring, corrosion prevention, and improvement of durability can be expected.
The amount of the pigment (C) is preferably 5 parts by mass or more, more preferably 50 parts by mass or more, and still more preferably 100 parts by mass or more, based on 100 parts by mass of the copolyester (a). Further, it is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, and further preferably 200 parts by mass or less. If the amount of the pigment (C) is too small, the intended effects such as coloring and corrosion prevention may not be obtained. If the amount is too large, the flexibility of the coating film may be reduced.
< additive (D) >)
The copolyester (A) of the present invention may contain an additive (D) as required. Specific examples of the additive (D) are not particularly limited, but include acid catalysts such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, camphorsulfonic acid, and phosphoric acid compounds, base catalysts such as amine compounds, antifoaming agents, leveling agents, thermal aging inhibitors, ultraviolet absorbers, viscosity modifiers, and waxes. These substances may be used in 1 or 2 or more. The additive (D) can be freely mixed as long as it does not affect the physical properties of the coating film. Preferably, the amount is 0.1 to 5 parts by mass based on 100 parts by mass of the copolyester (A).
< organic solvent (E) >)
The organic solvent (E) used in the present invention is not particularly limited as long as it dissolves the copolyester (A). Specifically, aromatic hydrocarbons such as toluene, xylene and Solvesso (registered trademark), esters such as ethyl acetate, butyl acetate, propylene glycol methyl ether acetate and dibasic acid esters, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone, ethers such as n-butyl cellosolve and t-butyl cellosolve, and the like can be used, and they can be arbitrarily selected and mixed in consideration of solubility, evaporation rate (drying property), and the like. Among them, a mixed solvent of aromatic hydrocarbons and ketones is preferable, and a mixed solvent of Solvesso and cyclohexanone is preferable.
The organic solvent (E) is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and further preferably 150 parts by mass or more, based on 100 parts by mass of the copolyester (a). Further, it is preferably 500 parts by mass or less, more preferably 400 parts by mass or less, and further preferably 300 parts by mass or less. If the amount is too small, the storage stability may be lowered, and if the amount is too large, the cost may be increased, which is not practical.
< Metal primer coating >
The metal primer coating of the present invention is a coating comprising a copolyester (a), a crosslinking agent (B), a pigment (C), an additive (D), and an organic solvent (E).
< Metal-coated plate >
The metal-coated sheet of the present invention is a sheet having the metal primer coating of the present invention as a primer layer on at least one surface of a metal sheet. The coating method is not particularly limited, and roll coater coating, curtain coater coating, air spraying, electrostatic spraying, screen printing, and the like can be used.
The metal plate is not particularly limited, and is preferably a metal plate such as a hot-rolled steel plate, an electrogalvanized steel plate, an alloy-plated steel plate, an aluminum-zinc alloy-plated steel plate, an aluminum plate, a tin-plated steel plate, a stainless steel plate, a copper-plated steel plate, a tin-free steel, a nickel-plated steel plate, an extremely thin tin-plated steel plate, or a chromium-treated steel plate.
Examples
The present invention will be specifically described below with reference to examples. In the present example and comparative example, parts represent parts by mass.
(1) Measurement of composition of copolyester (A)
Using 400MHz1H-nuclear magnetic resonance spectroscopy apparatus (hereinafter sometimes abbreviated toNMR) was used to determine the molar ratio of the polycarboxylic acid component and the polyol component constituting the copolyester (A). Deuterated chloroform was used as a solvent. When the acid value of the copolyester is increased by post-addition of an acid (Japanese: post-acid addition), the molar ratio of each component is calculated assuming that the total amount of acid components other than the acid component used in the post-addition of an acid is 100 mol%.
(2) Measurement of number average molecular weight of copolyester (A)
After 4mg of the sample (copolyester (A)) was dissolved in 4mL of tetrahydrofuran, the resulting solution was filtered through a filter of polytetrafluoroethylene having a pore size of 0.2. mu.m. This was used as a sample solution, and analysis was performed by Gel Permeation Chromatography (GPC). The device is TOSOH HLC-8220, the detector is a differential refractive index detector, and tetrahydrofuran is used as a mobile phase, and the measurement is carried out at the flow rate of 1 mL/min and the column temperature of 40 ℃. The columns are manufactured by KF-802, 804L and 806L manufactured by Showa electrician. The molecular weight standard was monodisperse polystyrene, and the number average molecular weight was calculated by omitting the portion corresponding to a molecular weight of less than 1000 from the standard polystyrene conversion value.
(3) Determination of the glass transition temperature
Measured using a differential scanning calorimeter (SII Co., DSC-200). 5mg of the sample (copolyester (A)) was placed in an aluminum push-cap type container and sealed, and cooled to-50 ℃ using liquid nitrogen. Then, the temperature was raised to 150 ℃ at a temperature raising rate of 20 ℃/min, and in the endothermic curve obtained in the temperature raising process, the temperature at the intersection of the extension of the base line before the onset of the endothermic peak (glass transition temperature or lower) and the tangent to the endothermic peak (tangent showing the maximum slope from the rising portion of the peak to the apex of the peak) was set to the glass transition temperature (Tg, unit:. degree.C.)
(4) Measurement of acid value
A0.2 g sample (copolyester (A)) was accurately weighed and dissolved in 40mL of chloroform. Subsequently, titration was performed with a 0.01N ethanol solution of potassium hydroxide. The indicator is phenolphthalein. The potassium hydroxide equivalent was obtained for each sample, and the measured value was converted to 10 per unit6g equivalent of sample, in equivalent/106g。
(5) Measurement of reduced viscosity eta sp/c (dl/g)
A sample (copolyester (A))0.10g of 25cc of a mixed solvent of phenol/tetrachloroethane (weight ratio: 6/4) was measured at 30 ℃ using an Ubbelohde tube.
The following shows production examples of the copolyester (A) of the present invention and a copolyester as a comparative example.
Production example of copolyester (a1)
809 parts of dimethyl terephthalate, 793 parts of dimethyl isophthalate, 19 parts of trimellitic anhydride, 407 parts of ethylene glycol, 540 parts of neopentyl glycol, 287 parts of triethylene glycol and 0.03 mol% of tetrabutyl orthotitanate as a catalyst to all acid components were charged into a reaction vessel equipped with a stirrer, a condenser and a thermometer, and the temperature was raised from 160 ℃ to 220 ℃ over 4 hours, and the transesterification reaction was carried out while passing through a methanol removal step. Then, the polycondensation reaction was carried out by reducing the pressure to 5mmHg for 20 minutes in the reaction system and then raising the temperature to 250 ℃. Then, the pressure was reduced to 0.3mmHg or less, and the polycondensation reaction was carried out for 60 minutes, followed by taking out. From the results of the composition analysis by NMR, the molar ratio of the resulting copolyester (a1) was: terephthalic acid/isophthalic acid/trimellitic acid/ethylene glycol/neopentyl glycol/triethylene glycol-50/49/1/40/40/20 [ molar ratio [ ]]. Further, the number average molecular weight was 7000, the glass transition temperature was 40 ℃ and the acid value was 20eq/106g. The results are shown in Table 1.
Production examples of copolyesters (a2) to (a10)
The copolyesters (a2) to (a11) of the present invention were produced by changing the kinds and mixing ratios of the raw materials according to the production examples of the copolyester (a 1). The results are shown in Table 1.
[ Table 1]
Example 1
Preparation of Metal primer coating (A1)
80 parts of the copolyester (a1) was dissolved in a mixed solvent of 100 parts of cyclohexanone and 100 parts of Solvesso 150. To this, 50 parts of calcium silicate, 13 parts of aluminum tripolyphosphate, and 37 parts of titanium oxide were added, and the mixture was dispersed for 6 hours by using a shaker. Then, 20 parts of CYMEL 303 (melamine curing agent, available from Allnex) as a crosslinking agent and 0.2 part of dodecylbenzenesulfonic acid as a curing catalyst were added to prepare a metallic primer coating (Al) of the present invention.
Examples 2 to 10 and comparative examples 1 to 3
Preparation of Metal primer coatings (A2) - (Kl)
In the same manner as the metal primer coating (Al), metal primer coatings (a2) to (Kl) were obtained as examples or comparative examples of the present invention. The mixing ratio is shown in table 2.
[ Table 2]
Evaluation of Metal-coated sheet
Production of test piece
A hot-dip galvanized steel sheet having a thickness of 0.5mm was prepared, and the metal primer coating described in the above examples was applied thereto so that the thickness after drying became 5 μm, and the steel sheet was dried at 210 ℃ for 45 seconds. Subsequently, a top coat paint composed of 16 parts by mass of a copolyester resin having a number average molecular weight of 15000 and a glass transition temperature of 38 ℃,4 parts by mass of a melamine resin, 20 parts by mass of titanium oxide and 60 parts by mass of cyclohexanone was applied thereon so that the film thickness after drying became 15 μm, and the film was dried at 250 ℃ for 60 seconds to obtain a test piece of a metal-coated plate.
(film hardness)
The pencil lead was pressed against the coated surface of the test piece of the metal-coated plate at an angle of 45 degrees and slid forward with a load of 1 kg. The hardness of the pencil lead was evaluated as the highest hardness without causing scars when H, F, HB, B and 2B were used from the harder ones. The higher the hardness, the higher the hardness of the coating film, and the more difficult it is to cause scratches.
Evaluation criteria
O: above H
△：F～B
X: 2B or less
(flexibility)
The above-mentioned test piece of the metal-coated plate was subjected to a 180 ° bending test at 25 ℃. Cracks in the coating film were visually observed. 2T is the case where 2 metal plates having the same thickness as the test metal plate were sandwiched and bent, and no cracks were generated in the coating film. The smaller the number, the better the flexibility.
○：0～2T
△：3～4T
X: above 5T
(Corrosion resistance)
The ends of the test pieces of the metal-coated plate were protected with tape, and after a crosscut (cross cut) was made on the surface of the test pieces until reaching the substrate with a cutter, a neutral salt spray test was carried out for 500 hours by the method described in J1S Z2371-2015. The size of the bulge of the cross-cut portion of the coated plate after the test was measured. The smaller the bump size, the better the corrosion resistance.
Evaluation criteria
O: diameter of 3mm or less
And (delta): the diameter is more than 3mm and less than 7mm
X: diameter of 7mm or more
(high solid compatibility (solution viscosity))
The resulting copolyester (A) was dissolved in a mixed solution of cyclohexanone and Solvesso l50 at the same weight ratio at a solid content concentration of 60 wt%, and the solution viscosity was measured at 25 ℃ using a B-type rotational viscometer (model EM, manufactured by Tokyo instruments, spindle No.4, 12 rpm). If the solution viscosity exceeds 200 poise, handling in the production of the coating material becomes difficult.
Evaluation criteria
O: less than 130 poise
And (delta): above 130 poise and below 200 poise
X: over 200 poises
(chemical resistance)
The ends of the test pieces of the metal-coated plate were protected with tape, and the test pieces were immersed in a 5 wt% aqueous solution of sodium hydroxide at 25 ℃ for 48 hours, and then evaluated by visual observation for appearance. The less the ridges, etc., the better the chemical resistance.
O: no bump-micro bumps with diameter less than 1mm
And (delta): with large ridges of diameter greater than 1mm
X: film peeling
Industrial applicability
The copolyester and the coating composition of the present invention are excellent in processability, corrosion resistance and chemical resistance, and are useful as a resin for a primer for a metal plate. Particularly useful as a component used for coil coating for home appliances.
Claims (4)
1. A copolyester A which comprises a polycarboxylic acid component and a polyol component as copolymerized components, wherein when the total amount of the polycarboxylic acid component is 100 mol%, the amount of the aromatic dicarboxylic acid component is 95 to 100 mol%, and the amount of the aliphatic dicarboxylic acid component is 0 to 5 mol%; and 1 to 30 mol% of triethylene glycol when the total polyol component is 100 mol%; the glass transition temperature of the copolyester A is in the range of 25-50 ℃, and the number average molecular weight of the copolyester A is in the range of 4000-9000.
2. The copolyester A according to claim 1, which contains no aliphatic dicarboxylic acid component.
3. A metallic primer coating comprising the copolyester A according to claim 1 or 2, a crosslinking agent B, a pigment C, an additive D and an organic solvent E.
4. A metal-coated plate having the metallic primer coating of claim 3 as a primer layer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
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| JP2015-182806 | 2015-09-16 | ||
| JP2015182806 | 2015-09-16 | ||
| PCT/JP2016/069141 WO2017047197A1 (en) | 2015-09-16 | 2016-06-28 | Copolymerized polyester and metal primer coating material using same |
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| CN107849230A CN107849230A (en) | 2018-03-27 |
| CN107849230B true CN107849230B (en) | 2021-02-05 |
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| CN201680040100.4A Active CN107849230B (en) | 2015-09-16 | 2016-06-28 | Copolyester and metal primer coating using the same |
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| JP (1) | JP6724921B2 (en) |
| KR (1) | KR20180055758A (en) |
| CN (1) | CN107849230B (en) |
| TW (1) | TWI719998B (en) |
| WO (1) | WO2017047197A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2018084064A1 (en) * | 2016-11-04 | 2018-05-11 | Dic株式会社 | Polyester polyol resin and coating |
| WO2018084065A1 (en) * | 2016-11-04 | 2018-05-11 | Dic株式会社 | Polyester polyol resin and coating |
| WO2020149082A1 (en) * | 2019-01-17 | 2020-07-23 | 東洋紡株式会社 | Copolyester and aqueous dispersion |
| TW202138424A (en) * | 2020-02-17 | 2021-10-16 | 日商東洋紡股份有限公司 | Aromatic polyester and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH11121270A (en) * | 1997-10-17 | 1999-04-30 | Toyo Metallizing Co Ltd | Dielectric polyester film for capacitor and plastic film capacitor |
| JP3768145B2 (en) * | 2001-03-21 | 2006-04-19 | 東洋鋼鈑株式会社 | Thermoplastic resin-coated metal plate and can using the same |
| JP2004339446A (en) * | 2003-05-19 | 2004-12-02 | Mitsubishi Rayon Co Ltd | Acrylic syrup composition, resin mortar and method for laying laminate |
| JP2010235647A (en) * | 2009-03-30 | 2010-10-21 | Unitika Ltd | Polyether-ester block copolymer, and adhesive and laminate comprising the same |
| JP5578891B2 (en) * | 2010-03-11 | 2014-08-27 | ユニチカ株式会社 | Aqueous polyester resin dispersion, method for producing the same, and resin film obtained therefrom |
| CN104220483B (en) * | 2012-03-28 | 2017-02-22 | 东洋纺株式会社 | Polyester resin, resin composition for can paint, painted metal plate for can, and can |
| JP6339380B2 (en) * | 2014-02-26 | 2018-06-06 | ユニチカ株式会社 | Polyester resin composition and laminate thereof |
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2016
- 2016-06-28 CN CN201680040100.4A patent/CN107849230B/en active Active
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| CN107849230A (en) | 2018-03-27 |
| WO2017047197A1 (en) | 2017-03-23 |
| TW201712051A (en) | 2017-04-01 |
| JP6724921B2 (en) | 2020-07-15 |
| JPWO2017047197A1 (en) | 2018-07-05 |
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