Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/63—Additives non-macromolecular organic
• • 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
• • 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
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/181—Acids containing aromatic rings
• • 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
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/20—Polyesters having been prepared in the presence of compounds having one reactive group or more than two reactive groups
• • 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
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/65—Additives macromolecular
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
  • B32B15/09—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyesters
• • 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
  • C08G2390/00—Containers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/0025—Crosslinking or vulcanising agents; including accelerators

Definitions

• the present invention relates to a polyester resin with excellent curability and a composition for coating metal plates. More specifically, the present invention relates to a metal plate coating composition which is mainly composed of a polyester resin having furandicarboxylic acid as a copolymerization component and is particularly excellent in curability, workability and dent resistance.
• Polyester resins are widely used as raw materials for resin compositions used in paints, coating agents, and adhesives.
• a polyester resin is generally composed of a polyhydric carboxylic acid and a polyhydric alcohol. By selecting and combining polyhydric carboxylic acid and polyhydric alcohol, the molecular weight can be freely controlled, and the resulting polyester resin is used in various applications such as paints and adhesives.
• metal cans such as beverage cans and food cans are coated with an organic resin to prevent food from corroding the metal (corrosion resistance) and to preserve the flavor and flavor of the contents (flavor properties).
• corrosion resistance corrosion resistance
• flavor properties preservation the flavor and flavor of the contents
• Patent Document 1 discloses an acid component consisting of 80 to 100 mol% of an aromatic dicarboxylic acid containing 70 to 95 mol% of terephthalic acid and 0 to 20 mol% of a polybasic acid other than the aromatic dicarboxylic acid, and 2-methyl- A polyester resin obtained by reacting 1,3-propanediol and 1,4-cyclohexanedimethanol as essential components with a glycol component containing 25 to 50 mol % of 2-methyl-1,3-propanediol. It is disclosed that a polyester resin for can coating in which the total weight of terephthalic acid and 1,4-cyclohexanedimethanol is in the range of 45 to 65% by weight of the polyester resin is excellent in workability and stain resistance.
• An object of the present invention is to provide a polyester resin having excellent curability, processability, retort resistance, and dent resistance, and a coating composition using the same.
• a polyester resin comprising a polyhydric carboxylic acid component and a polyhydric alcohol component as copolymer components and satisfying the following conditions (i) to (iii). (i) It has 10 mol % or more of polycarboxylic acid components having a furan skeleton among the polycarboxylic acid components constituting the polyester resin. (ii) The polyhydric alcohol component constituting the polyester resin is two or more. (iii) it has a glass transition temperature of 70° C.
• polyester resin according to [1] which has a reduced viscosity of 0.2 to 0.8 dl/g, an acid value of less than 70 eq/t, and no melting point.
• polyvalent carboxylic acid components constituting the polyester resin in addition to the polyvalent carboxylic acid component having a furan skeleton, aromatic polyvalent carboxylic acid, aliphatic polyvalent carboxylic acid, and alicyclic polyvalent carboxylic acid.
• the polyester resin according to the above [1] or [2] which contains 5 mol % or more of at least one selected polyvalent carboxylic acid component.
• a metal containing the polyester resin according to any one of [1] to [8] and a curing agent at a ratio of the polyester resin/curing agent 98/2 to 50/50 (mass ratio)
• a board coating composition [10] The metal plate coating composition according to [9] above, wherein the curing agent is at least one curing agent selected from amino resins, phenol resins and isocyanate compounds.
• A can containing the coated metal sheet according to [12] as a constituent material.
• the total copolymerization ratio of the ethylene glycol component and the 1,2-propylene glycol component is 50 mol% or more, and the 1,2-propylene component is more prevalent than the ethylene glycol component.
• A can comprising the coated metal sheet according to [19] as a constituent material.
• the polyester resin of the present invention has a very high curability, and the coating film obtained is excellent in workability, retort resistance, and dent resistance. is suitable for In addition, since the resin contains non-petroleum-derived components, it can contribute to solving environmental problems such as suppression of carbon dioxide increase.
• the polyester resin of the present invention is a polyester resin characterized by satisfying the following requirements (i) to (iii).
• the polyester resin of the present invention must contain 10 mol % or more of the polycarboxylic acid component having a furan skeleton among the polycarboxylic acid components constituting the polyester resin. It is preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 30 mol % or more.
• the content is at least the above lower limit, the mobility of the polyester resin is improved, and the polarity is also increased, thereby improving the reactivity with the curing agent and improving the curability of the polyester resin.
• sufficient coating film performance can be obtained even at low temperatures, it can contribute to energy saving in the coating process.
• the contribution to the reduction of the environmental load due to the non-petroleum component origin is increased.
• the polycarboxylic acid component having a furan skeleton is preferably 95 mol% or less, more preferably 90 mol% or less, and 80 mol% or less. is more preferable. By making it below the said upper limit, the flexibility of a polyester resin can improve and dent resistance can be improved.
• the polyvalent carboxylic acid component having a furan skeleton is not particularly limited as long as it contains a furan structure in the structure of the compound, and examples thereof include furandicarboxylic acid. Specific examples include 2,5-furandicarboxylic acid.
• these derivatives may be used as raw materials, and examples of derivatives include alkyl esters having 1 to 4 carbon atoms, among which methyl ester, ethyl ester, n-propyl ester, isopropyl ester, and the like. Methyl ester is preferred, and more preferred.
• These furan skeleton-containing carboxylic acids and/or derivatives thereof may be used singly or in combination of two or more.
• Requirement (ii)> Requirement (ii) will be explained. It is necessary that two or more kinds of polyhydric alcohol components constitute the polyester resin of the present invention. By using two or more polyhydric alcohol components, the flexibility and mobility of the polyester resin are improved, and the workability is improved. In particular, by using a combination of a straight-chain polyhydric alcohol and a polyhydric alcohol having a side chain, the polyester resin is imparted with appropriate flexibility, and together with the improvement of the curability, the workability can be improved.
• the crosslink density of the coating film is improved, and retort resistance, dent resistance, and resistance are improved.
• Various physical properties such as content properties can be improved.
• the glass transition temperature (Tg) of the polyester resin of the present invention must be 70° C. or higher, preferably 72° C. or higher, more preferably 74° C. or higher, still more preferably 76° C. or higher, and particularly preferably is above 78°C. If it is less than the above lower limit, in addition to the dent resistance, retort resistance and/or content resistance may be poor. Although there is no particular upper limit for the glass transition temperature (Tg), it is usually 130° C. or lower, preferably 120° C. or lower, and more preferably 110° C. or lower. Incidentally, Tg in the present invention substantially coincides with T ig defined in JIS K 7121-1987, but strictly speaking, it is a value determined by the method specified in Examples.
• the glass transition temperature (Tg) of the polyester resin of the present invention can be adjusted by changing the copolymer component and its ratio. For example, by increasing the copolymerization ratio of an aromatic polycarboxylic acid or an alicyclic polycarboxylic acid as a polyvalent carboxylic acid component constituting the polyester resin, Tg tends to increase. Tg tends to increase by increasing the copolymerization ratio of an alicyclic polyhydric alcohol or an aliphatic polyhydric alcohol having 3 or less carbon atoms in the main chain as the alcohol component.
• the Tg tends to be lowered, and as the polyhydric alcohol component constituting the polyester resin, the main chain carbon Tg tends to be lowered by increasing the copolymerization ratio of the aliphatic polyhydric alcohol having a number of 4 or more.
• the reduced viscosity of the polyester resin of the present invention is preferably 0.2 to 0.8 dl/g, more preferably 0.25 to 0.75 dl/g, still more preferably 0.3 to 0.7 dl/g, and 0.25 to 0.75 dl/g. 35 to 0.6 dl/g is particularly preferred. If the reduced viscosity is less than 0.2 dl/g, the curability will be insufficient, and the toughness of the coating film will be insufficient, possibly resulting in a decrease in workability. On the other hand, if the reduced viscosity exceeds 0.8 dl/g, the solvent solubility may decrease, and the paint stability may decrease and the coating workability may decrease.
• the reduced viscosity can be adjusted by changing the polymerization time and temperature of the polyester resin and the degree of pressure reduction during polymerization (in the case of reduced pressure polymerization).
• the reduced viscosity in this invention be the value determined by the method as described in an Example.
• the acid value of the polyester resin of the present invention is preferably less than 70 eq/t, more preferably 60 eq/t or less, even more preferably 50 eq/t or less, and particularly preferably 40 eq/t or less. If the above upper limit is exceeded, the water resistance of the polyester resin may decrease, resulting in a decrease in dent resistance, retort resistance, content resistance, and the like.
• the polyester resin of the present invention preferably has no melting point. Specifically, it is preferred that a differential scanning calorimeter (DSC) is used to raise the temperature from ⁇ 100° C. to 250° C. at a rate of 20° C./min, and that no clear melting peak is shown during the heating process. By not exhibiting a melting point, the stability when dissolved in a solvent is improved. When the polyester resin has a melting point and crystallinity, solvent solubility and/or paint stability may be lowered, and workability and/or dent resistance may be lowered.
• DSC differential scanning calorimeter
• the polyester resin of the present invention has 10 mol % or more of a polycarboxylic acid component having a furan skeleton as a polycarboxylic acid component.
• polyvalent carboxylic acid components constituting the polyester resin of the present invention in addition to the polyvalent carboxylic acid component having a furan skeleton, aromatic polyvalent carboxylic acid, aliphatic polyvalent carboxylic acid and alicyclic polyvalent carboxylic acid
• At least one selected polyvalent carboxylic acid component preferably has 5 mol% or more, more preferably 10 mol% or more, further preferably 20 mol% or more, particularly 30 mol% or more. preferable. By making it more than the said lower limit, the solubility of a polyester resin improves and workability
• Polyvalent carboxylic acid components other than the polyvalent carboxylic acid component having a furan skeleton include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,8-naphthalenedicarboxylic acid. acids, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5-[4-sulfophenoxy]isophthalic acid and alkali metal salts thereof, etc.
• aromatic polycarboxylic acid components aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, fumaric acid, maleic acid, itaconic acid, and citraconic acid component, alicyclic polyvalent carboxylic acid components such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, 1,2-cyclohexenedicarboxylic acid, and 2,5-norbornanedicarboxylic acid.
• aromatic polycarboxylic acid components are preferred from the viewpoint of reactivity, water resistance, and heat resistance, and terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are particularly preferred.
• Polyhydric alcohol components constituting the polyester resin of the present invention include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3- Methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol , 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol, 4-methyl-1,7 - aliphatic glycols such as heptanediol, 4-methyl-1,8-octaned
• Two or more of these can be selected and used.
• a combination of a linear aliphatic glycol having 4 or less carbon atoms and an aliphatic glycol having 5 or less carbon atoms having a side chain it is preferable to use a combination of a linear aliphatic glycol having 4 or less carbon atoms and an aliphatic glycol having 5 or less carbon atoms having a side chain.
• Linear aliphatic glycols having 4 or less carbon atoms are ethylene glycol, 1,3-propanediol and 1,4-butanediol, and aliphatic glycols having 5 or less carbon atoms having side chains include 1,2 -propylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,3-pentanediol, etc. .
• ethylene glycol as a linear aliphatic glycol having 4 or less carbon atoms and 1,2-propylene glycol as an aliphatic glycol having 5 or less carbon atoms having a side chain.
• 1,2-propylene glycol it is preferable to use a combination of trimethylolpropane as a polyhydric alcohol having a functionality of 3 or more.
• the copolymerization ratio of ethylene glycol is preferably 5 mol% or more, more preferably 10 mol%, in the total polyhydric alcohol component. more preferably 13 mol % or more, particularly preferably 15 mol % or more. By making it more than the said lower limit, curability, retort-proof property, and/or content-proof property may become more favorable. Moreover, the copolymerization ratio of ethylene glycol is preferably 45 mol % or less, more preferably 40 mol % or less, and still more preferably 35 mol % or less in the total polyhydric alcohol component. If it is less than the above upper limit, the crystallinity of the polyester resin may be suppressed, and solvent solubility and/or paint stability may be improved.
• the copolymerization ratio of 1,2-propylene glycol is preferably 45 mol% or more in the total polyhydric alcohol component. More preferably 50 mol % or more, still more preferably 55 mol % or more, particularly preferably 60 mol % or more, most preferably 65 mol % or more. Solvent solubility and/or paint stability may become more favorable as it is more than the said lower limit.
• the copolymerization ratio of 1,2-propylene glycol is preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less, in the total polyhydric alcohol component, Particularly preferably, it is 80 mol % or less. If it is at most the above upper limit, workability and/or curability may be better.
• the polyhydric alcohol component constituting the polyester resin of the present invention it is preferable to use both a linear diol component and a diol component having a side chain.
• the linear diol in the present invention means an aliphatic diol having no branches in the hydrocarbon chain connecting the hydroxyl groups at both ends of the molecule. Specific examples thereof include ethylene glycol, 1,3-propanediol, Mention may be made of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,9-nonanediol.
• the diol having a side chain in the present invention means an aliphatic diol having a branch in the hydrocarbon chain connecting the hydroxyl groups at both ends of the molecule, and the branch may be one or two or more.
• Specific examples thereof include 1,2-propylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 1-methyl-1,8-octanediol, 3-methyl-1 ,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl-1,8-octanediol, 4-propyl-1,8-octanediol
• the total copolymerization ratio of the linear diol component and the diol component having a side chain is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, in the total polyhydric alcohol component, More preferably 70 to 100 mol %, particularly preferably 80 to 100 mol %, most preferably 90 to 100 mol %.
• the retort resistance and/or content resistance of the coating film tend to be better, and the dent resistance tends to be improved.
• the diol having a side chain is higher in molar ratio than the copolymerization ratio of the straight-chain diol component.
• the copolymerization ratio of the components is preferably high, and the value obtained by subtracting the copolymerization ratio of the straight-chain glycol component from the copolymerization ratio of the diol component having a side chain is preferably 10 mol% or more, more preferably 20% by mole. mol % or more, more preferably 30 mol % or more, and particularly preferably 35 mol % or more.
• the crystallinity of the polyester resin can be suppressed, the solvent solubility of the polyester resin and / or the storage stability of the paint is improved, and the processability and / or dent resistance of the coating film are improved. can be.
• the total copolymerization ratio of ethylene glycol and 1,2-propylene glycol is the total polyhydric alcohol component , preferably 50 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 70 to 100 mol%, particularly preferably 80 to 100 mol%, most preferably 90 to 100 mol %.
• the total polyhydric alcohol component preferably 50 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 70 to 100 mol%, particularly preferably 80 to 100 mol%, most preferably 90 to 100 mol %.
• the copolymerization ratio of the 1,2-propylene glycol component is higher than the copolymerization ratio of the ethylene glycol component in terms of molar ratio. is preferably high.
• the value obtained by subtracting the copolymerization ratio of ethylene glycol from the copolymerization ratio of 1,2-propylene glycol is preferably 10 mol% or more, more preferably 20 mol% or more, and still more preferably 30 mol% or more. Yes, particularly preferably 35 mol % or more.
• the crystallinity of the polyester resin can be suppressed, the solvent solubility of the polyester resin and / or the storage stability of the paint is improved, and the processability and / or dent resistance of the coating film are improved. can be.
• a polyhydric carboxylic acid component and/or a polyhydric alcohol component may be copolymerized with a trifunctional or higher component.
• tri- or more functional polycarboxylic acid components include trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, etc.
• tri- or more functional polyhydric alcohol components include glycerin, trimethylolethane, trimethylolpropane, mannitol, sorbitol, pentaerythritol, ⁇ -methylglucoside and the like.
• the copolymerization ratio is preferably 0 to 5 mol% in the polyhydric carboxylic acid component or polyhydric alcohol component, and more It is preferably 0 to 4 mol %, more preferably 0.1 to 3 mol %, particularly preferably 0.1 to 2 mol %. If the above upper limit is exceeded, the flexibility of the polyester resin may be lost, the workability and/or dent resistance may be lowered, or gelation may occur during polymerization of the polyester.
• the polyester resin of the present invention may be given an acid value by any method.
• an acid value By imparting an acid value, effects such as improved curability with a curing agent and improved adhesion to metal materials for cans may be obtained.
• a method of imparting an acid value a depolymerization method in which a polyvalent carboxylic acid anhydride is added in the late stage of polycondensation, a prepolymer (oligomer) is made to have a high acid value at the stage, and then polycondensed to increase the acid value.
• the former depolymerization method is preferred because it is easy to operate and it is easy to obtain the target acid value.
• polyvalent carboxylic acid anhydrides used for acid addition in such depolymerization methods include phthalic anhydride, tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, and hexahydrophthalic anhydride. acid, ethylene glycol bis-anhydro-trimellitate, and the like. Preferred is trimellitic anhydride.
• the polymerization catalyst includes, for example, titanium compounds such as tetra-n-butyl titanate, tetraisopropyl titanate and titaniumoxyacetylacetonate, antimony compounds such as antimony trioxide and tributoxyantimony. , germanium oxide, tetra-n-butoxygermanium, and other germanium compounds, as well as acetates of magnesium, iron, zinc, manganese, cobalt, aluminum, and the like. These catalysts can be used singly or in combination of two or more.
• the method of the polymerization condensation reaction for producing the polyester resin of the present invention is not particularly limited. 2) Heating an alcohol ester of a polyhydric carboxylic acid and a polyhydric alcohol in the presence of an arbitrary catalyst to conduct an ester exchange reaction, followed by a polyhydric alcohol removal/polycondensation reaction. how to do it, etc.
• part or all of the polycarboxylic acid component may be replaced with an acid anhydride.
• various additives, stabilizers, etc. may be added depending on the purpose of use and various properties required so as not to impair the inherent properties of other thermoplastic resins.
• Antioxidants may be used in the polyester resin of the present invention, if necessary.
• Antioxidants are not particularly limited. -tri(4-hydroxy-2-methyl-5-t-butylphenyl)butane, 1,1-bis(3-t-butyl-6-methyl-4-hydroxyphenyl)butane, 3,5-bis(1 ,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, pentaerythritol tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate and the like.
• the amount to be added is preferably 0.1% by mass or more and 5% by mass or less based on the mass of the polyester resin. If it is less than 0.1% by mass, the effect of preventing thermal deterioration may be poor. If it exceeds 5% by mass, the color tone may be adversely affected.
• the metal plate coating composition of the present invention is a composition containing the polyester resin of the present invention, and preferably further contains a curing agent.
• a ratio of 92/8 to 70/30 (mass ratio) is more preferred, and a ratio of 90/10 to 75/25 (mass ratio) is particularly preferred.
• the amount of the curing agent is less than 2 parts by mass with respect to 98 parts by mass of the polyester resin, sufficient curability cannot be obtained, and processability, retort resistance, content resistance and/or dent resistance may deteriorate. If the amount of the curing agent exceeds 50 parts by mass with respect to 50 parts by mass of the polyester resin, unreacted curing agent components may remain and the dent resistance, retort resistance and content resistance may be lowered.
• the curing agent that constitutes the metal plate coating composition of the present invention is not particularly limited as long as it reacts with the polyester resin of the present invention to form a crosslinked structure.
• the curing agent that constitutes the metal plate coating composition of the present invention is not particularly limited as long as it reacts with the polyester resin of the present invention to form a crosslinked structure.
• phenol resins, amino resins, and isocyanate compounds are preferred from the viewpoint of hygiene and reactivity.
• it is more preferably an isocyanate compound, and more preferably a blocked isocyanate compound.
• isocyanate compound examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, tetramethylxylene diisocyanate, 4,4' -diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3 '-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naph
• Blocking agents include phenolic compounds such as phenol, cresol, ethylphenol, and butylphenol, 2-hydroxypyridine, butyl cellosolve, propylene glycol monomethyl ether, benzyl alcohol, methanol, ethanol, n-butanol, isobutanol, 2-ethylhexanol, and the like.
• active methylene compounds such as dityl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; acid amide compounds such as acetanilide and acetic amide , ⁇ -caprolactam, ⁇ -valerolactam, ⁇ -butyrolactam and other lactam compounds, imidazole, 2-methylimidazole and other imidazole compounds, urea, thiourea, ethyleneurea and other urea compounds, formamide oxime, acetaldoxime , acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime and cyclohexanone oxime; and amine compounds such as diphenylaniline, aniline, carbazole, ethyleneimine and polyethyleneimine.
• Such a reaction between the blocking agent and the isocyanate curing agent component can be carried out, for example, at 20 to 200°C using a known inert solvent or catalyst as necessary.
• the blocking agent is preferably used in an amount of 0.7 to 1.5 times the molar amount of the terminal isocyanate groups.
• the phenolic resin is preferably a resol-type phenolic resin synthesized from a phenolic compound.
• trifunctional or higher functional phenol compounds include phenol, m-cresol, m-ethylphenol, 3,5-xylenol, m-methoxyphenol, bisphenol-A and bisphenol-F.
• Bifunctional phenol compounds include o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, 2,5-xylenol and the like. These have two or more functional groups capable of being methylolated per molecule of the phenol compound, and can be synthesized by methylolation with formaldehyde or the like. These can be used singly or in combination of two or more.
• the blending ratio of these trifunctional or higher functional phenol compounds and difunctional phenol compounds is arbitrarily blended according to the required coating film (cured film), but is 1/99 to 100/0 (parts by mass). is preferred.
• the coating film requires hardness and acid resistance, it is preferable to use more than 30 parts by mass of a trifunctional or higher phenolic compound, and the coating film requires flexibility and low residual stress after processing.
• the amount of the tri- or higher functional phenol compound is preferably less than 50 parts by mass.
• formaldehydes used when making these phenolic compounds into phenolic resins include formaldehyde, paraformaldehyde, and trioxane, which can be used singly or in combination of two or more.
• a monohydric alcohol having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms can be used as the alcohol used to alkyl-etherify a portion of the methylol groups of the methylolated phenolic resin.
• the phenol resin has an average of 0.3 or more, preferably 0.5 to 3, alkoxymethyl groups per phenol nucleus from the viewpoint of reactivity and compatibility with the polyester resin. If the number is less than 0.3, the curability with the polyester resin may be poor and the workability may be lowered.
• a method for obtaining a phenolic resin in which these trifunctional or higher phenolic compounds and bifunctional phenolic compounds are mixed a method of mixing at an arbitrary ratio before forming a phenolic resin with formaldehyde, or a method of mixing with trifunctional
• the phenolic compounds and bifunctional phenolic compounds described above may be individually converted into phenolic resins and mixed at any mixing ratio.
• amino resins examples include methylol obtained by reacting amino components such as melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide with aldehyde components such as formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. modified amino resins.
• the above amino resins also include those obtained by etherifying the methylol group of this methylolated amino resin with an alcohol having 1 to 6 carbon atoms. These can be used alone or in combination of two or more. Amino resins with benzoguanamine or melamine are preferred.
• amino resins using benzoguanamine include methyl-etherified benzoguanamine resin obtained by etherifying a part or all of the methylol groups of methylolated benzoguanamine resin with methyl alcohol, butyl-etherified benzoguanamine resin obtained by butyl-etherifying with butyl alcohol, or methyl alcohol. Methyl ether etherified both with butyl alcohol and mixed etherified benzoguanamine resin with butyl ether are preferred. Isobutyl alcohol and n-butyl alcohol are preferable as the butyl alcohol.
• amino resins using melamine examples include methyl-etherified melamine resin obtained by etherifying a part or all of the methylol groups of methylolated melamine resin with methyl alcohol, butyl-etherified melamine resin obtained by butyl-etherifying with butyl alcohol, or methyl alcohol. Methyl ether etherified both with butyl alcohol and mixed etherified melamine resin with butyl ether are preferred.
• the metal plate coating composition of the present invention further contains a catalyst.
• a catalyst By containing a catalyst, the performance of the cured film can be improved.
• the curing agent is a phenolic resin or an amino resin
• examples of the catalyst include sulfuric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, camphorsulfonic acid, Phosphoric acid and amine-blocked (partially neutralized by adding amine) of these may be mentioned, and one or more of these may be used in combination.
• Dodecylbenzenesulfonic acid and neutralized products thereof are preferred in terms of compatibility with polyester resins and sanitation.
• the curing agent is an isocyanate compound
• organotin compounds such as stannous octoate and dibutyltin dilaurate, triethylamine, zinc compounds, aluminum compounds, etc.
• organotin compounds such as stannous octoate and dibutyltin dilaurate, triethylamine, zinc compounds, aluminum compounds, etc.
• Known inorganic pigments such as titanium oxide and silica, phosphoric acid and its esters, surface smoothing agents, antifoaming agents, dispersants, lubricants and the like are added to the metal plate coating composition of the present invention according to the required properties.
• known additives can be blended.
• lubricants are important for imparting lubricity to coating films required during the molding of DI cans and DR (or DRD) cans.
• suitable lubricants include silicone waxes, fluorine waxes, polyolefin waxes such as polyethylene, lanolin waxes, montan waxes, microcrystalline waxes, and carnauba waxes. Lubricants can be used singly or in combination of two or more.
• the metal plate coating composition of the present invention can be made into a paint by dissolving it in a known organic solvent.
• organic solvents used for coating include toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, methyl cellosolve, butyl cellosolve, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene Glycol monoacetate, methanol, ethanol, butanol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, Solvesso and the like. From these, one or two or more are selected and used in consideration of solubility, evaporation rate, and the like.
• composition for coating a metal plate of the present invention can be blended with other resins for the purpose of modifying properties such as imparting flexibility and adhesion to the coating film.
• other resins include ethylene-polymerizable unsaturated carboxylic acid copolymers and ethylene-polymerizable carboxylic acid copolymer ionomers, and at least one or more resins selected from these are blended. In some cases, flexibility and/or adhesion of the coating film can be imparted thereby.
• the metal plate coating composition of the present invention can be applied to various known substrates.
• the substrate is not particularly limited, and examples thereof include chin-free steel plates, tin plates, bonderized steel plates, galvanized steel plates, aluminum and stainless steel.
• Metal sheets made of these metal materials are subjected to phosphate treatment, chromic acid chromate treatment, phosphoric acid chromate treatment, anti-corrosion treatment with other anti-corrosive agents, and surface treatment for the purpose of improving the adhesion of the coating film in advance. You can use things.
• the coating method to the base material is not particularly limited either, and examples thereof include bar coater, curtain flow, roll coat, dipping, spray and brush coating.
• the coating amount is not particularly limited, and the thickness of the coating film after drying is usually adjusted to about 1 to 30 ⁇ m, preferably about 5 to 15 ⁇ m.
• the baking conditions for the coating film are usually in the range of about 100 to 300° C. for about 5 seconds to about 30 minutes, and further in the range of about 150 to 250° C. for about 20 seconds to about 15 minutes. things are preferable.
• composition for coating a metal plate of the present invention can be suitably used as a coated metal plate by laminating it on the surface of the metal plate.
• the coated metal sheet can be applied as a constituent material of cans, and examples of cans containing the coated metal sheet as a constituent material include beverage cans, cans for canning, and their lids or caps.
• ⁇ Polyester resin> (1) Measurement of Resin Composition A polyester resin sample was dissolved in heavy chloroform and subjected to 1H-NMR analysis using a nuclear magnetic resonance (NMR) device 400-MR manufactured by VARIAN. A molar ratio was obtained from the integral value ratio.
• NMR nuclear magnetic resonance
• Tg glass transition temperature
• Tm melting point
• Gel fraction (% by mass) [ ⁇ (Y) - copper foil mass ⁇ / ⁇ (X) - copper foil mass ⁇ ] x 100 (judgement) ⁇ : Gel fraction is 90% by mass or more ⁇ : Gel fraction is 80% by mass or more and less than 90% by mass ⁇ : Gel fraction is 60% by mass or more and less than 80% by mass ⁇ : Gel fraction is less than 60% by mass
• the test piece was bent 180° in the direction where the cured film was on the outside, and cracking of the cured film occurring at the bent portion was evaluated by measuring the electric current value.
• the bending process was performed without inserting anything (so-called 0T).
• a sponge width 20 mm, depth 50 mm, thickness 10 mm
• a 1% NaCl aqueous solution was placed on an aluminum plate electrode (width 20 mm, depth 50 mm, thickness 0.5 mm). The vicinity of the central portion of the bent portion of the test piece was brought into contact with the sponge so as to be parallel to the 20 mm side.
• a DC voltage of 5.0 V was applied between the aluminum plate electrode and the non-coated portion on the back surface of the test piece, and the energization value was measured.
• a smaller energization value means better bending characteristics. (judgement) ⁇ : Less than 0.5 mA ⁇ : 0.5 mA or more and less than 2.0 mA ⁇ : 2.0 mA or more
• a sponge (width 20 mm, depth 50 mm, thickness 10 mm) immersed in a 1 mass% NaCl aqueous solution was placed on an aluminum plate electrode (width 20 mm, depth 50 mm, thickness 0.5 mm), The projecting portion of the impacted test piece was brought into contact with the sponge, and a DC voltage of 5.0 V was applied between the aluminum plate electrode and the non-coated portion of the back surface of the test piece to measure the energization value.
• a smaller energization value means better bending characteristics.
• polyester resin was subjected to post-polymerization under a vacuum of 1 mmHg or less for 120 minutes.
• Synthesis Example 1 was obtained.
• the obtained polyester resin had a reduced viscosity of 0.50 dl/g, an acid value of 65 eq/t, a glass transition temperature (Tg) of 79° C., and no melting point was observed.
• a metal plate coating composition was created using the obtained polyester resin, and the curability, workability, retort resistance, and dent resistance were evaluated.
• Table 2 shows the formulation of the metal plate coating composition and the evaluation results.
• Cymel 303 Methylated melamine, manufactured by Allnex Corporation Cymel 1123: Methyl/ethylated benzoguanamine, manufactured by Allnex Corporation Phenodur PR521: Phenolic curing agent, Desmodur BL 2078/2, manufactured by Sumika Covestro Urethane Co., Ltd. isocyanate
• the polyester resin showed a melting point and had insufficient solubility in the solvent, and could not be dissolved in the solvent, and the coating film performance was evaluated. could not.
• the metal plate coating composition using the polyester resin of the present invention has excellent reactivity with the curing agent, and the obtained cured film (coating film) has excellent workability, retort resistance, and dent resistance. Both sexes are excellent.
• the product of the present invention is a polyester resin excellent in curability, workability, retort resistance, and dent resistance, a metal plate coating composition containing the same, a coated metal plate, and a metal can for food and beverages, It is suitable as a main component of a metal plate coating composition used for precoat metal coating.

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• 2023
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