Classifications

• • 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
• • 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
  • C08G63/183—Terephthalic acids
• • 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
  • C08G63/123—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/137—Acids or hydroxy compounds containing cycloaliphatic 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
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/181—Acids containing aromatic rings
  • C08G63/185—Acids containing aromatic rings containing two or more aromatic rings
  • C08G63/187—Acids containing aromatic rings containing two or more aromatic rings containing condensed aromatic rings
  • C08G63/189—Acids containing aromatic rings containing two or more aromatic rings containing condensed aromatic rings containing a naphthalene ring
• • 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
  • C08G63/199—Acids or hydroxy compounds containing cycloaliphatic 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
  • 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
  • C08G63/52—Polycarboxylic acids or polyhydroxy compounds in which at least one of the two components contains aliphatic unsaturation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • 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
• • 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
  • C09D167/06—Unsaturated polyesters having carbon-to-carbon unsaturation
• • 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
  • C09D5/02—Emulsion paints including aerosols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/50—Aqueous dispersion, e.g. containing polymers with a glass transition temperature (Tg) above 20°C

Definitions

• the present invention relates to polyester resin compositions. More specifically, it relates to a polyester resin composition suitable for can coating, and more specifically, a polyester resin composition suitable for coating the inner surface of a can containing beverages and foods (hereinafter collectively referred to as food and drink), and the same. Aqueous dispersions containing coatings, coating compositions, and coatings and metal cans having such coatings.
• 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).
• These coatings are required to have workability, corrosion resistance, adhesion to metal materials, curability, and the like. Depending on the application, it may be subjected to high temperature and high humidity conditions such as retort sterilization. When applied to the outer surface side, it is also required that the coating film does not whiten.
• epoxy paints such as epoxy-phenol paints, epoxy-amino paints, epoxy-acrylic paints, polyester-phenol paints, polyester - Polyester-based paints such as amino-based paints and vinyl chloride-based paints are widely used.
• bisphenol A which is a raw material of epoxy resin, may have estrogenic effects and affect the brains of fetuses and infants.
• Vinyl chloride-based paints also have the problem of stabilizers and the generation of dioxins during incineration.
• Formaldehyde which is used as a raw material for phenolic resins, amino resins, etc., and remains in paints is known to be harmful to the human body, such as carcinogenicity, and to adversely affect the flavor of the contents.
• a resin composition for metal containers or metal lids for example, an acrylic-modified polyester resin obtained by graft-polymerizing a polymerizable unsaturated monomer component to a polyester resin having an ethylenic double bond at the end of the resin. and a ⁇ -hydroxyalkylamide cross-linking agent dispersed in an aqueous medium have been proposed (Patent Document 1).
• Patent Document 2 proposes a coating composition comprising a polyester polyol and a blocked polyisocyanate curing agent.
• An object of the present invention is to form a coating film having excellent properties such as curability, retort resistance, workability, etc., by suppressing harmful outgassing because the polyester resin alone can be cured without substantially containing a curing agent. It is to provide a polyester resin and a polyester resin composition capable of achieving the above.
• the present inventors have made various studies on the above and found that a polyester resin composition containing a polyester resin having a predetermined amount of acid value and a specific structure can be cured by the polyester resin alone without substantially using a curing agent. I found what I could do. Furthermore, by controlling the amount of catalyst, it was found that a polyester resin coating film having excellent balance between curability and processability, no harmful outgassing, and retort resistance remarkably improved can be obtained, resulting in the present invention. That is, the present invention consists of the following configurations.
• a polyester resin composition comprising a polyester resin (A) and satisfying the following requirements (i) to (iii).
• the polyester resin (A) has an acid value of 100 eq/ton or more.
• the polyester resin (A) has a diol (a) having two primary hydroxyl groups and no alicyclic structure as a polyol component constituting the polyester resin (A); It has either or both of a diol (b) having a structure and a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure.
• the polyester resin (A) has an unsaturated dicarboxylic acid (d) as a polycarboxylic acid component constituting the polyester resin (A).
• the polyester resin (A) contains at least one selected from the group consisting of adipic acid, 2,6-naphthalenedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid as the polycarboxylic acid component constituting the polyester resin (A).
• the present invention can provide a polyester resin composition that does not generate harmful outgassing caused by a curing agent, has an excellent balance between curability and workability, and has significantly improved retort resistance, and a coating film thereof.
• the polyester resin composition of the present invention is a polyester resin composition characterized by containing a polyester resin (A) and satisfying the following requirements (i) to (iii).
• the polyester resin (A) must have an acid value of 100 eq/ton or more. It is preferably 200 eq/ton or more, more preferably 250 eq/ton or more, and still more preferably 300 eq/ton or more. If it is less than the above, there are few carboxyl groups serving as cross-linking points, so the curability may decrease. Furthermore, when the acid value is less than the above range, the thermal decomposition reaction proceeds predominantly over the curing reaction when heated to 240° C., and workability may deteriorate. Moreover, aqueous dispersion becomes easy because an acid value has more than the said lower limit. Although there is no particular upper limit for the acid value, it is preferably 1200 eq/ton or less in order to reduce the amount of unreacted acid components and oligomers during the acid addition reaction.
• the acid value of the polyester resin (A) in the present invention can be given by any method.
• a method of imparting an acid value a method of addition reaction of a polycarboxylic anhydride in the late stage of polycondensation, a method of increasing the acid value in the prepolymer (oligomer) stage and then polycondensing it to obtain a polyester having an acid value
• the former method of addition reaction is preferred because of ease of operation and easy acquisition of the target acid value.
• carboxylic acid monoanhydrides include, for example, phthalic anhydride, succinic anhydride, anhydride Monoanhydrides such as maleic acid, trimellitic anhydride, itaconic anhydride, citraconic anhydride, 5-(2,5-dioxotetrahydrofurfuryl)-3-cyclohexene-1,2-dicarboxylic anhydride, hexahydroanhydride Phthalic acid, tetrahydrophthalic anhydride and the like can be mentioned, and one or more of these can be selected and used.
• trimellitic anhydride is preferred from the viewpoint of versatility and economy.
• carboxylic acid polyanhydrides include, for example, pyromellitic anhydride, 1,2,3 ,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, cyclopentanetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, ethylene glycol bistrimellitate dianhydride, 2,2′, 3,3′-diphenyltetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, ethylenetetracarboxylic dian
• a carboxylic acid monoanhydride and a carboxylic acid polyanhydride can be used alone or in combination. can also
• the polyester resin (A) in the present invention has, as a constituent polyol component, a diol (a) having two primary hydroxyl groups and no alicyclic structure, and a diol (b) having an alicyclic structure. and either or both of a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure.
• each component may also be referred to as component (a), component (b), and component (c).
• Component (a) readily forms an ester bond, while component (b) and component (c) Since the ester bond is more easily cleaved than the component (a), having the component (a) and the components (b) and (c) allows rearrangement and rearrangement of the ester bonds during heat treatment. It is presumed that bonding is facilitated and a coating film having both curability and flexibility, ie workability, can be formed.
• the diol (a) having two primary hydroxyl groups and no alicyclic structure in the polyester resin (A) is, for example, ethylene glycol, 1,3-propanediol, 2-butyl-2-ethyl-1,3- propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, 2,4-diethyl-1,5-pentanediol, 1 ,6-hexanediol, 2-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl-1,8-octanediol, Aliphatic glycols such as 1,9-nonanediol, polyether glycols such as diethylene glycol, triethylene glycol, polyethylene
• the copolymerization ratio of the diol (a) having two primary hydroxyl groups and no alicyclic structure in the polyester resin (A) is preferably 20 to 80 mol%, more preferably 20 to 60, in the total polyol component. mol %, more preferably 20 to 40 mol %. Within the above range, good curability and retort resistance are obtained.
• the polyester resin (A) in the present invention preferably has a diol (b) having an alicyclic structure as a polyol component. Having the diol (b) having an alicyclic structure facilitates compatibility between processability and retort resistance.
• the diol (b) having an alicyclic structure constituting the polyester resin (A) in the present invention is, for example, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane Glycols, hydrogenated bisphenols and the like can be mentioned, and one or more of these can be selected and used. Among them, 1,4-cyclohexanedimethanol is preferably used from the viewpoint of curability, workability and retort resistance.
• the copolymerization ratio of the diol (b) having an alicyclic structure that constitutes the polyester resin (A) in the present invention is preferably 5 to 50 mol%, more preferably 10 to 40 mol%, in the total polyol component. It is preferably 20 to 30 mol %. Within the above range, the workability is good.
• the polyester resin (A) in the present invention preferably has a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure as a polyol component.
• Examples of the diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure in the polyester resin (A) include 1,2-propylene glycol and 1,2-butanediol. etc., and one or more of these can be selected and used. Among them, it is preferable to use 1,2-propylene glycol.
• the copolymerization ratio of the diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure in the polyester resin (A) is 5 to 75 mol% of the total polyol component. It is preferably 10 to 65 mol %, and still more preferably 15 to 50 mol %. Within the above range, good curability and retort resistance are obtained.
• the polyester resin (A) in the present invention has an unsaturated dicarboxylic acid (d) as a constituent polycarboxylic acid component.
• unsaturated dicarboxylic acid (d) By containing the unsaturated dicarboxylic acid (d), the curability can be improved by a reaction that generates intermolecular carbon-carbon bonds due to cleavage of unsaturated bonds during heat treatment.
• unsaturated dicarboxylic acid (d) include fumaric acid, maleic acid, itaconic acid, citraconic acid, 2,5-norbornanedicarboxylic acid, tetrahydrophthalic acid, and acid anhydrides thereof. More than one species can be used.
• the copolymerization ratio of the unsaturated dicarboxylic acid (d) is preferably 5 to 20 mol % in the polycarboxylic acid component. More preferably 10 to 15 mol %. By being within the above range, it is possible to achieve both workability and curability.
• Polycarboxylic acid components constituting the polyester resin (A) in the present invention include, for example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,8-naphthalene.
• aromatic dicarboxylic acid components such as dicarboxylic acids. These may be used alone or in combination of two or more. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred.
• Examples of other polycarboxylic acid components constituting the polyester resin (A) in the present invention include aliphatic dicarboxylic acid components and alicyclic dicarboxylic acid components.
• Aliphatic dicarboxylic acid components include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid and the like.
• Alicyclic dicarboxylic acid components include 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, and 1,2-cyclohexenedicarboxylic acid. One or more of these can be selected and used. Among them, adipic acid and 1,4-cyclohexanedicarboxylic acid are preferred in terms of reactivity and economy.
• the copolymerization ratio thereof is preferably 5 to 40 mol % in the polycarboxylic acid component. More preferably 10 to 30 mol %. If it is out of the above range, the glass transition temperature of the polyester resin (A) may be greatly lowered and the retort resistance may be lowered.
• the polyester resin (A) in the present invention preferably has a branched structure. Having a branched structure means having a branched structure in the main chain of the polyester.
• a polycarboxylic acid component and/or a polyol An example is a method of copolymerizing a tri- or more functional component as a part of the component.
• Tri- or more functional polycarboxylic acid components include, for example, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, etc.
• Tri- or more functional polyols include glycerin, trimethylolethane, trimethylolpropane, mannitol, sorbitol, pentaerythritol, ⁇ -methylglucoside and the like.
• the polyester resin (A) has a branched structure, the crosslink density is increased when rearrangement and recombination of ester bonds occur during heat treatment, so curability and workability can be improved.
• the copolymerization ratio of the tri- or higher functional polycarboxylic acid component is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, when the total polycarboxylic acid component is 100 mol%, More preferably, it is 1 mol % or more. Also, it is preferably 7 mol % or less, more preferably 6 mol % or less, still more preferably 5 mol % or less, and particularly preferably 4 mol % or less.
• the copolymerization ratio of the trifunctional or higher polyol component is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, still more preferably 1, when the total polyol component is 100 mol%. mol% or more.
• the polyester resin may lose its flexibility and workability, or may gel during polymerization of the polyester.
• Raw materials derived from biomass resources can be used for the polycarboxylic acid component and the polyol component that constitute the polyester resin (A) in the present invention.
• Biomass resources are stored by converting the energy of sunlight into starch and cellulose through the photosynthesis of plants, the bodies of animals that grow by eating plants, and the bodies of plants and animals that are processed. This includes products that can be Among these, more preferable biomass resources are plant resources, such as wood, rice straw, rice husk, rice bran, old rice, corn, sugar cane, cassava, sago palm, bean curd refuse, corn cob, tapioca cass, bagasse, vegetable oil cake, potato.
• buckwheat soybeans, oils and fats, used paper, papermaking residue, marine product residue, livestock excrement, sewage sludge, food waste, and the like. More preferred are corn, sugar cane, cassava and sago palm.
• the esterification/exchange reaction all monomer components and/or low polymers thereof are heated and melted for reaction.
• the esterification/exchange reaction temperature is preferably 180 to 250°C, more preferably 200 to 250°C.
• the reaction time is preferably 1.5 to 10 hours, more preferably 3 to 6 hours.
• the reaction time is the time from reaching the desired reaction temperature to the subsequent polycondensation reaction.
• the polyol component is distilled off from the esterified product obtained by the esterification reaction at a temperature of 220 to 280° C. under reduced pressure, and the polycondensation reaction proceeds until the desired molecular weight is reached.
• the reaction temperature for polycondensation is preferably 220 to 280°C, more preferably 240 to 275°C.
• the degree of pressure reduction is preferably 130 Pa or less. If the degree of pressure reduction is insufficient, the polycondensation time tends to become long, which is not preferable. As for the pressure reduction time from the atmospheric pressure to 130 Pa or less, it is preferable to gradually reduce the pressure over 30 to 180 minutes.
• an organic titanate compound such as tetrabutyl titanate, an organic tin compound such as germanium dioxide, antimony oxide, and tin octylate is used for polymerization.
• Organic titanic acid compounds are preferable from the viewpoint of reaction activity, and germanium dioxide is preferable from the viewpoint of resin coloring.
• the glass transition temperature of the polyester resin (A) in the present invention is preferably 40°C or higher, more preferably 60°C or higher, from the viewpoint of water resistance, particularly retort resistance of the coating film. Although there is no particular upper limit for the glass transition temperature, it is usually 130° C. or less.
• the reduced viscosity of the polyester resin (A) of the present invention is preferably 0.2-0.6 dl/g, more preferably 0.3-0.5 dl/g. If the reduced viscosity is 0.2 dl/g or less, the curability will be insufficient, and the toughness of the coating film will be insufficient, so that there is a risk that it will not withstand molding into cans after being coated on a metal plate. On the other hand, when the reduced viscosity is 0.6 dl/g or more, the melt viscosity and the solution viscosity become high, and not only the workability is lowered, but also the number of terminal hydroxyl groups is decreased, so that it may not be possible to impart a sufficient acid value.
• the polyester resin composition of the present invention contains substantially no curing agent.
• substantially free of curing agent means that the curing agent content is less than 1 part by mass (as solid content) with respect to 100 parts by mass (as solid content) of the polyester resin.
• the curing agent refers to a known curing agent that reacts with the polyester resin (A) of the present invention to form a crosslinked structure. Reaction, cation addition reaction, or anion addition reaction, etc., reaction to generate intermolecular carbon-carbon bonds, condensation reaction with polyvalent carboxylic acid groups and polyhydric alcohol groups in polyester resin, polyaddition reaction, Alternatively, formation of an intermolecular bond by transesterification or the like can be mentioned.
• curing agents include phenol resins, amino resins, isocyanate compounds, epoxy compounds, ⁇ -hydroxylamide compounds, unsaturated bond-containing resins, and the like.
• the content of the curing agent is less than 1 part by mass with respect to 100 parts by mass of the polyester resin (A) (solid content). More preferably less than 0.5 parts by weight, even more preferably less than 0.1 parts by weight, most preferably no curing agent. If the content of the curing agent is higher than the above range, not only is it economically uneconomical, but also the self-condensation reaction between the curing agents reduces processability, volatilizes the blocking agent, and generates harmful outgas such as formaldehyde. Long-term storage stability may be poor.
• the polyester resin composition of the present invention can be cured by heat treatment at 240°C for 1 hour even if it does not substantially contain a curing agent.
• the cured product is not contained as much as possible.
• the content of such a cured product can be known using the tetrahydrofuran (THF)-insoluble matter as an index.
• the polyester resin composition of the present invention preferably has a tetrahydrofuran-insoluble content of 10% by mass or more when heat-treated at 240°C for 1 hour.
• a polyester resin composition and a coating film thereof having an excellent balance between retort resistance and workability can be obtained.
• the THF-insoluble content is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 70% by mass. If the amount is less than 10% by mass, the curability will be insufficient, and the toughness of the coating film will be insufficient, which may result in a decrease in retort resistance and may not withstand molding into cans after coating a metal plate.
• the polyester composition of the present invention preferably has a THF-insoluble content of less than 10% by mass when heat-treated at 150°C for 30 minutes. It is more preferably less than 5% by mass, still more preferably less than 1% by mass, and may even be 0% by mass.
• THF-insoluble matter is less than the above value under relatively low temperature heating conditions of about 150° C., it is possible to suppress the generation of aggregates during dissolution in a solvent or formation of an aqueous dispersion.
• the polyester resin composition of the present invention contains a polyester resin (A) and satisfies the requirements (i) to (iii), so that the polyester resin alone can be cured substantially without using a curing agent. can. Therefore, the polyester resin composition of the present invention may be in the form of the polyester resin (A) alone without containing components other than the polyester resin (A).
• the polyester resin composition of the present invention preferably further contains a catalyst (B).
• a catalyst (B) By containing the catalyst (B), the self-crosslinking property of the polyester resin (A) during the heat treatment can be promoted and the curability can be improved.
• catalysts include acid catalysts such as sulfuric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, camphorsulfonic acid, and phosphoric acid, and amine blocks ( partially neutralized with amine), organic tin compounds such as dibutyltin dilaurate, titanium compounds such as titanium tetrabutoxide, zinc compounds such as zinc acetate, hafnium compounds such as hafnium chloride/THF complex, scandium triflate, etc. Examples include rare earth compounds, and one or more of these can be used in combination. Of these, dodecylbenzenesulfonic acid and neutralized products thereof are preferred from the viewpoint of compatibility with the polyester resin (A) and sanitation.
• (A)/(B) 100/0.01 to 0.5 (mass ratio), more preferably 100/0 0.05 to 0.4 (mass ratio), most preferably 100/0.1 to 0.3 (mass ratio).
• the catalyst (B) may be contained in the polyester resin (A) or may be added later. From the viewpoint of avoiding gelation during polymerization of the polyester resin (A), it is preferable to add the catalyst (B) after the production of the polyester resin (A).
• a radical polymerization inhibitor (C) may be added to the polyester resin composition of the present invention. It is mainly used to prevent gelation due to the cleavage of unsaturated bonds when the polyester resin (A) is polymerized. good.
• the radical polymerization inhibitor (C) include known antioxidants such as phenol antioxidants, phosphorus antioxidants, amine antioxidants, sulfur antioxidants and inorganic compound antioxidants.
• Phenolic antioxidants include 2,5-di-t-butylhydroquinone, 4,4′-butyldenbis(3-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4 -hydroxy-5-t-butylphenyl)butane, 1,3,5-tris-methyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris(3 ,5-di-t-butyl-4-hydroxyphenyl)isocyanurate and derivatives thereof.
• Phosphorus antioxidants include tri(nonylphenyl)phosphite, triphenylphosphite, diphenylisodecylphosphite, trioctadecylphosphite, tridecylphosphite, diphenyldecylphosphite, 4,4′-butylidene-bis (3-methyl-6-t-butylphenyl ditridecylphosphite), distearyl-pentaerythritol diphosphite, trilauryltrithiophosphite, and derivatives thereof.
• Amine antioxidants include phenyl-beta-naphthylamine, phenothiazine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-betanaphthyl-p-phenylenediamine, N-cyclohexyl-N'- Phenyl-p-phenylenediamine, aldol-alpha-naphthylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymers, and derivatives thereof.
• sulfur-based antioxidants examples include thiobis(N-phenyl-beta-naphthylamine, 2-mercaptobenchiazole, 2-mercaptobenzimidazole, tetramethylthiuram disulfide, nickel isopropylxanthate, etc., or derivatives thereof.
• Nitro compound antioxidants include 1,3,5-trinitrobenzene, p-nitrosodiphenylamine, p-nitrosodimethylaniline, 1-chloro-3-nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, Nitrobenzene, p-nitrobenzoic acid, nitrobenzene, 2-nitro-5-cyanothiophene, etc., or derivatives thereof.
• Inorganic compound-based antioxidants include FeCl3, Fe(CN)3, CuCl2, CoCl3, Co(ClO4)3, Co(NO3)3, Co2(SO4)3, and the like.
• radical polymerization inhibitor (C) used in the present invention among the above antioxidants, phenolic antioxidants and amine antioxidants are preferable in terms of thermal stability, and have a melting point of 120° C. or higher and a molecular weight of is more preferably 200 or more, and more preferably 170° C. or more. Specific examples include phenothiazine and 4,4'-butyldenbis(3-methyl-6-t-butylphenol).
• polyester resin composition of the present invention 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 according to the required properties. of 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, and microcrystalline waxes. Lubricants can be used singly or in combination of two or more.
• the polyester resin 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.
• the polyester resin composition of the present invention can be made into a powder coating by a known pulverization method.
• known pulverization methods include pulverization methods.
• the polyester resin composition of the present invention and, if necessary, a mixture of antirust pigments and additives are dry-mixed in a mixer such as a tumbler mixer or a Henschel mixer, and melt-kneaded in a kneader.
• a mixer such as a tumbler mixer or a Henschel mixer
• melt-kneaded in a kneader melt-kneaded in a kneader.
• a general kneader such as a single-screw or twin-screw extruder, a triple roll, or a lab blast mill can be used.
• the kneaded material is solidified by cooling, and the solidified material is coarsely pulverized and finely pulverized to obtain a pulverized material.
• pulverizers include a jet pulverizer that pulverizes using a supersonic jet stream, and a space formed between a rotor and a liner that rotate at high speed.
• An impact pulverizer that is introduced and pulverized can be used.
• additives may be added to the pulverized product.
• a powder coating composition can be obtained by classifying the pulverized product to adjust the powder to a desired particle size and particle size distribution.
• a known classifier capable of removing excessively pulverized toner base particles by classification by centrifugal force and wind power can be used, for example, a swirling wind classifier (rotary wind classifier) can be used.
• the polyester resin composition of the present invention can be blended with other resins for the purpose of improving the flexibility and adhesion of the coating film.
• other resins include amorphous polyesters, crystalline polyesters, ethylene-polymerizable unsaturated carboxylic acid copolymers, and ethylene-polymerizable carboxylic acid copolymer ionomers, and are selected from these. Blending at least one or more resins may sometimes impart flexibility and/or adhesion to the coating film.
• the polyester resin composition of the present invention is a metal plate made of a metal material that can be used for beverage cans, cans for cans, lids, caps, etc., it can be applied to one or both sides of the metal plate, and if necessary, to the end face. Can be painted.
• the metal material include tinplate, tin free steel, and aluminum.
• 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 polyester resin composition of the present invention can be applied to a metal plate and cured by a known coating method such as roll coater coating or spray coating.
• the coating film thickness is not particularly limited, but the dry film thickness is preferably in the range of 3 to 18 ⁇ m, more preferably 5 to 15 ⁇ m.
• the baking conditions for the coating film are usually about 180 to 260° C. for about 10 minutes to 2 hours, preferably about 200 to 240° C. for about 5 minutes to 1 hour.
• the polyester resin composition of the present invention can also be dispersed in an aqueous medium and used as an aqueous polyester resin dispersion.
• a method of making the polyester resin (A) used in the present invention into a water dispersion the polyester resin (A) is dissolved in a water-soluble organic solvent in which the polyester resin (A) is soluble, and if necessary, a basic compound, Method (a) of sequentially adding and dispersing water, Method (b) of adding a polyester resin (A), water, a water-soluble organic solvent that dissolves the polyester resin (A), and, if necessary, a basic compound, followed by heating and dispersing. etc.
• polyester resin (A) the former method (a) is preferred from the viewpoint of film-forming properties.
• the temperature for dissolving the polyester resin (A) is preferably 40 to 160°C, more preferably 50 to 140°C, still more preferably 60 to 120°C, and most preferably 70 to 100°C. If the temperature is less than 40°C, the polyester resin (A) may not be sufficiently dissolved, and the entanglement of the molecular chains cannot be sufficiently released. If the temperature exceeds 160°C, the polyester resin (A) deteriorates. This is because the risk of inviting Organic solvents in which the polyester resin (A) can be dissolved by heating in the temperature range of 40 to 160° C.
• methyl ethyl ketone dimethylacetamide, dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3 -dioxane, 1,3-dioxolane, 1,2-hexanediol, methyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, propylene glycol monobutyl ether, triethylene glycol monobutyl ether and the like.
• methyl ethyl ketone, butyl cellosolve, propylene glycol monopropyl ether, propylene glycol monobutyl ether and the like are preferred.
• the temperature of the polyester resin solution is cooled to 100° C. or lower, and water and, if necessary, a basic compound are successively added while stirring the resin solution. It is necessary to obtain an aqueous dispersion by performing a phase inversion.
• a compound that volatilizes during the drying or baking process during coating film formation is preferable, such as ammonia and/or a compound having a boiling point of 250° C. or less.
• An organic amine compound or the like is used.
• These basic compounds are required in an amount capable of at least partially neutralizing the carboxyl groups of the polyester resin (A), and specifically, 0.5 to 1.5 equivalents are added to the carboxyl group equivalents. is desirable.
• the average particle size of the polyester resin water dispersion according to the present invention is very important because it greatly affects the coating film appearance and storage stability, and is preferably 30 to 250 nm. More preferably 50 to 200 nm, particularly preferably 70 to 150 nm.
• the average particle size exceeds 250 nm, not only is the dispersion stability significantly lowered, but also the film-forming properties are lowered, resulting in poor appearance of the resulting film.
• it is less than 30 nm the film-forming property tends to be remarkably improved, but this tends to cause coalescence and aggregation between the dispersed particles, resulting in a high possibility of causing thickening and poor dispersion, which is preferable. do not have.
• the polyester resin aqueous dispersion of the present invention is preferably produced with a resin solid content concentration of 10 to 45% by mass. It is more preferably 15 to 40% by mass, and still more preferably 20 to 35% by mass. If the resin solid content concentration exceeds 45% by mass, the viscosity of the aqueous dispersion increases, and aggregation between resin particles tends to occur, resulting in a significant decrease in dispersion stability. On the other hand, if the content is less than 10% by mass, it is difficult to say that it is practical from both the production and usage standpoints.
• the polyester resin aqueous dispersion of the present invention is ideal for the inner surface coating of food and beverage cans.
• Various additives may be blended depending on the purpose for the inner surface coating of cans for food and beverages. Coatability, smoothness of the coating film, leveling agents and surfactants for improving the appearance, lubricants for preventing scratches on the coating film, further coloring pigments and in some cases polyester resins other than the polyester resin of the present invention, Resins other than polyester resins, such as acrylic resin emulsions and polyurethane resin emulsions, can be blended to the extent that the objects of the present invention, such as food sanitation and flavor properties, are not impaired.
• a paint using the polyester resin aqueous dispersion of the present invention can be applied to a metal substrate for cans such as aluminum, stainless steel, and tinplate by a gravure roll coater, a comma coater, a spray method, or the like.
• the film thickness is not particularly limited, but the dry film thickness is usually in the range of 3 to 18 ⁇ m, preferably 5 to 15 ⁇ m.
• the baking conditions for the coating film are usually about 180 to 260° C. for about 10 minutes to 2 hours, preferably about 200 to 240° C. for about 5 minutes to 1 hour.
• ⁇ Polyester resin (A)> (1) Measurement of Resin Composition A sample of polyester resin (A) was dissolved in deuterated 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
• THF-insoluble content was measured by coating a polyester resin composition on a copper foil so that the thickness after drying was 10 ⁇ m, and heating at 240 ° C. for 1 hour.
• the mass of the sample heated to 10 cm long and 2.5 cm wide before immersion in THF was (X), immersed in 60 ml of THF at 25 ° C. for 1 hour, and dried at 100 ° C. for 10 minutes.
• the mass of the sample was taken as the mass (Y) after immersion in THF, and it was obtained by the following formula.
• THF insoluble content [ ⁇ (Y) - copper foil mass ⁇ / ⁇ (X) - copper foil mass ⁇ ] x 100
• the THF-insoluble matter after heat treatment at 150° C. for 30 minutes was determined in the same manner as above, except that the temperature was set at 150° C. and the heating was performed for 30 minutes.
• test piece A polyester resin composition was coated on one side of a tin plate (JIS G 3303 (2008) SPTE, 70 mm ⁇ 150 mm ⁇ 0.3 mm) with a bar coater so that the film thickness after drying was 10 ⁇ 2 ⁇ m, and the baking condition was 240.
• the obtained test piece was bent 180° in the direction in which the cured film was on the outside, and cracking of the cured film occurring at the bent portion was evaluated by measuring the 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 plate, 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 1.0 mA ⁇ : 1.0 mA or more and less than 2.0 mA ⁇ : 2.0 mA or more
• Curability Evaluation Gauze felt impregnated with methyl ethyl ketone was pressed against the cured film surface of the test piece so as to make 1 cm 2 contact, and a rubbing test was performed by applying a load of 500 g. The number of times until the cured film was peeled off (once per reciprocation) was evaluated according to the following criteria.
• TBT tetra-n-butyl titanate
• polyester resin (synthesis example (a)).
• the obtained polyester resin had a reduced viscosity of 0.33 dl/g, a glass transition temperature (Tg) of 65° C., and an acid value of 300 eq/t.
• Synthesis examples (b) to (r) Polyester resins (Synthesis Examples (b) to (r)) having the resin compositions shown in Table 1 were produced by the direct polymerization method in the same manner as in Synthesis Example (b), except that the charging composition was changed.
• a polyester resin composition was prepared using the obtained polyester resin and evaluated for workability, curability and retort resistance.
• Tables 2 and 3 show the formulation of the polyester resin composition and the evaluation results.
• the cured film (coating film) obtained from the polyester resin composition using the polyester resin (A) of the present invention is excellent in all of its workability, curability and retort resistance. ing.
• the polyester resin did not have an unsaturated dicarboxylic acid (d) as a polycarboxylic acid component, so the curability was poor.
• the polyester resin did not contain both the (b) component and the (c) component as polyol components, the retort resistance was poor.
• the polyester resin did not have component (a) as a polyol component, and was inferior in retort resistance.
• Comparative Examples 4 and 5 since the acid value of the polyester resin was low, the curability was insufficient, and the workability and retort resistance were also inferior.
• the product of the present invention is a polyester resin composition and a polyester resin aqueous dispersion, which are excellent in workability, curability and retort resistance, and a paint or coating film containing the same, which can be used for food and beverage metal cans. It is suitable as a main ingredient of paint to be applied.

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• 2022
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