EP0753018A1 - Compositions de revetement vinylique en phase aqueuse a base de melanges de resines, et leurs utilisations - Google Patents

Compositions de revetement vinylique en phase aqueuse a base de melanges de resines, et leurs utilisations

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Publication number
EP0753018A1
EP0753018A1 EP95914213A EP95914213A EP0753018A1 EP 0753018 A1 EP0753018 A1 EP 0753018A1 EP 95914213 A EP95914213 A EP 95914213A EP 95914213 A EP95914213 A EP 95914213A EP 0753018 A1 EP0753018 A1 EP 0753018A1
Authority
EP
European Patent Office
Prior art keywords
resin
monomer
aqueous dispersion
polyol
groups
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95914213A
Other languages
German (de)
English (en)
Inventor
Shanti Swarup
Ronald R. Ambrose
James B. O'dwyer
Lawrence J. Fitzgerald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PPG Industries Inc
Original Assignee
PPG Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/219,603 external-priority patent/US5428084A/en
Application filed by PPG Industries Inc filed Critical PPG Industries Inc
Publication of EP0753018A1 publication Critical patent/EP0753018A1/fr
Withdrawn legal-status Critical Current

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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
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
    • C08G59/4246—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof polymers with carboxylic terminal groups
    • C08G59/4261—Macromolecular compounds obtained by reactions involving only unsaturated carbon-to-carbon bindings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • 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
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/18—Homopolymers or copolymers of nitriles
    • 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
    • C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins

Definitions

  • the present invention relates to vinyl (acrylic) resins and the use thereof in resinous blends with modified epoxy resins.
  • the utility of the present invention relates to water-based coating compositions of resinous blends which have been found to be very suitable for can or coil coatings.
  • coatings intended for use in food and beverage industries generally are expected to meet a number of requirements in order to be commercially acceptable.
  • the coating should adhere well to the base metal and should possess flexibility, extensibility and adhesion characteristics so as to withstand the processing of the container itself.
  • the coating sometimes also must be able to resist heat which can be encountered during processing of the container and its contents.
  • the coating itself should not affect the taste of a food or beverage which is put into the coated container.
  • Film continuity is another characteristic sought after, and one aspect of this requirement is that coatings be blister-free. Blistering is a defect that arises from gas by-products of curing the coating becoming trapped in the coating, and is a problem particularly associated with coated areas in which the coating is relatively thick.
  • a coating that is prone to blistering requires special precautions to be taken during coating to assure that a maximum allowable coating thickness is not exceeded on any portion of the article being coated. It would be desirable if greater latitude could be permitted as to allowable coating thicknesses without inducing blistering.
  • Blister resistance also relates to coating line speed, such as on a production line roll for coating continuous strips of metal. It has been found that blistering can be induced by high line speeds with coatings that have relatively low blister-free thicknesses, regardless of the thickness of the coating actually applied. Therefore, it would be desirable for coatings to have higher blister-free thicknesses for the sake of higher line speeds.
  • blush is a haziness in the film believed to be caused by absorption of water. Blush is particularly evident with container coatings that are subjected to high temperature, high humidity conditions during a canning process.
  • 4,605,476 discloses waterborne can coatings that comprise blends of epoxy resins that have been defunctionalized with ammonia or amine and acrylic copolymers that may incorporate N-(alkoxymethyl) acrylamide or methacrylamide. Mono-alcohols are disclosed as copolymerization solvents for the acrylic component. Although these coatings provide acceptable performance at relatively low line speed, susceptibility to blistering increases with increasing line speeds. It would be desirable to provide greater latitude in coating application conditions, including faster line speeds, particularly improved blister resistance.
  • the present invention uses close to a 1:1 ratio of equivalents of epoxy groups to equivalents of ammoma or amine.
  • the equivalent ratio may range from 1:1.5 to 1.5: 1, preferably from 1:1.3 to 1.3:1. Not only does this substantially reduce the extent to which emissions of excess amine or ammonia need to be collected, but also, it has been found that coating compositions containing defunctionalized epoxies exhibit improved blush and stain resistance when subjected to high temperature processing conditions.
  • the present invention additionally encompasses a coating composition comprising, as an essential film-former, a resinous blend of:
  • the invention also involves a method of defunctionalizing a polyepoxide comprising: dissolving a polyepoxide in solvent; and, introducing ammonia, an amine, or a mixture thereof into the polyepoxide solution so as to react therewith while maintaining the temperature below 60 °C for a period of at least one hour.
  • a method of defunctionalizing a polyepoxide comprising: dissolving a polyepoxide in solvent; and, introducing ammonia, an amine, or a mixture thereof into the polyepoxide solution so as to react therewith while maintaining the temperature below 60 °C for a period of at least one hour.
  • novel vinyl addition copolymers are produced from an acid group-containing monomer, an N- (alkoxymethyl) acrylamide or N-(alkoxymethyl) methacrylamide monomer, and at least one other vinyl monomer, the copolymerization being carried out in the presence of a solvent including a polyol, wherein the polyol molecule includes OH groups of different reactivity.
  • an increase in coating thickness latitude results when the copolymerization is carried out in the presence of an alcohol solvent reactive with the acrylamide groups of the vinyl addition copolymer.
  • Polyols have been found to be substantially more reactive in this regard than mono- alcohols.
  • many polyols when used for this purpose have been found to yield unacceptable molecular weight increase, in some cases resulting in gelation which renders the resin useless for the intended purpose.
  • the polyols are those which are characterized by OH groups having different reactivity with regard to the acrylamide groups.
  • the polyols include combinations of a primary OH group, a secondary OH group, or a tertiary OH group, but avoid having two or more primary OH groups, two or more secondary OH groups, or two or more tertiary groups.
  • the present invention further encompasses a coating composition
  • a coating composition comprising as an essential film-former a resinous blend of:
  • the present invention still further encompasses a coating composition
  • a coating composition comprising as an essential film-former a resinous blend of:
  • Improvements in coating application latitude have been found with this type of composition when the resins are dispersed into water by less than fully neutralizing the acid groups contained in the vinyl addition resin.
  • these improvements were found with less than 65 percent neutralization, preferably less than 50 percent neutralization.
  • the coating compositions additionally may contain curing agents such as aminoplasts, phenolic resins, and/or urea- formaldehyde resins.
  • curing agents such as aminoplasts, phenolic resins, and/or urea- formaldehyde resins.
  • the preferred vinyl addition resins can be formed by polymerizing from about 5 to about 25 weight percent of an alpha, beta ethylenically unsaturated carboxylic acid with from about 75 to about 95 weight percent of at least one other copolymerizable vinyl monomer or monomers.
  • the resulting copolymers have an acid value of from about 20 to about 350, preferably from about 45 to about 150.
  • Preferred vinyl addition resins are formed from about 7 percent to about 15 percent of the alpha, beta-ethylenically unsaturated carboxylic acid and from about 85 percent to about 93 percent of the other copolymerizable vinyl monomer.
  • alpha, beta-ethylenically unsaturated carboxylic acids are those containing from 3 to 8 carbon atoms such as acrylic acid and methacrylic acid, both of which are preferred. Acids such as itaconic acid, maleic acid, fumaric acid, mono-esters of unsaturated dicarboxylic acids, e.g., methyl hydrogen maleate and ethyl hydrogen fumarate as well as anhydrides where they exist, may also be used.
  • the other copolymerizable vinyl monomer or monomers for the vinyl addition resin copolymerization may be selected from a wide variety of materials depending upon the properties desired.
  • the other copolymerizable monomer may be a vinyl aromatic compound such as styrene, alpha-methyl styrene, tertiary butyl styrene, vinyl toluene and vinyl xylene.
  • styrene alpha-methyl styrene
  • tertiary butyl styrene vinyl toluene
  • vinyl xylene vinyl xylene.
  • Additional monomers which may be used are the alkyl esters of methacrylic acid which contain from 1 to 3 carbon atoms in the alkyl group. Specific examples of such esters are methyl methacrylate and ethyl methacrylate.
  • Monomers which may be used and which provide flexibility to the coatings are the alkyl esters of acrylic acid having from 2 to 17 carbon atoms in the alkyl group and alkyl esters of methacrylic acid having from 4 to 17 carbon atoms in the alkyl group.
  • Examples of monomers of this type are ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethyl-hexyl acrylate, butyl methacrylate, 2-ethyl-hexyl methacrylate, lauryl methacrylate, and stearyl methacrylate.
  • Still other monomers include vinyl monomers such as ethylene, propylene and the like, the vinyl halides, vinylidene halides, vinyl versatate, vinyl acetate, dialkyl maleate, allyl chloride, allyl alcohol, 1,3-butadiene, 2-chlorobutene, methyl vinyl ether, acrylamide, methacrylamide, acrylonitrile, and methacrylonitrile.
  • vinyl monomers such as ethylene, propylene and the like, the vinyl halides, vinylidene halides, vinyl versatate, vinyl acetate, dialkyl maleate, allyl chloride, allyl alcohol, 1,3-butadiene, 2-chlorobutene, methyl vinyl ether, acrylamide, methacrylamide, acrylonitrile, and methacrylonitrile.
  • Mixtures of any of the above-described vinyl monomers may be used and are preferred.
  • Mixtures of vinyl addition resins formed separately can also be used. Additionally, monomers may be included
  • a preferred example of a third monomer included in the vinyl addition copolymer resin is an N-(alkoxymethyl)acrylamide or N-(alkoxymethyl)methacrylamide having 1 to 4 carbon atoms in the alkoxy group.
  • the preferred member of this group is N-(butoxymethyl)acrylamide.
  • Examples of other members include N-(butoxymethyl)methacrylamide and N-(ethoxymethyl)acrylamide.
  • These acrylamide monomers may be included in amounts typically ranging from 10 to 50 weight percent of the monomer mixture.
  • Vinyl addition resins described above can be prepared by free radical initiated polymerization of a mixture of the copolymerizable acrylic monomers by solution polymerization techniques.
  • the monomers are dissolved in a solvent or a mixture of solvents and polymerized until the free monomeric content is reduced to below about 0.5 percent, preferably below about 0.1 percent.
  • free radical initiators include azobis(alpha-gamma)-dimethyl- valeronitrile, tertiary-butyl perbenzoate, tertiary-butyl peracetate and benzoyl peroxide.
  • the solvent is first heated to reflux and a mixture of the monomers and the free radical initiator are added simultaneously and slowly to the refluxing solvent. Additional catalyst is optionally added and the reaction mixture held at polymerizing temperatures so as to reduce the free monomer content of the reaction mixture.
  • the copolymerization is carried out in the presence of a solvent. It has also been discovered that advantages in application latitude may be obtained by including a polyol in the solvent, wherein the polyol molecule includes OH groups of different reactivity. It has been found that an increase in coating thickness latitude results when the copolymerization is carried out in the presence of an alcohol solvent reactive with the acrylamide groups that are preferably included in the vinyl addition copolymer. Polyols have been found to be substantially more reactive in this regard than mono-alcohols. However, the use of many polyols leads to unacceptable molecular weight increase, in some cases resulting in gellation which renders the resin useless for the intended purpose.
  • the polyols useful for this purpose are those which are characterized by OH groups having differing reactivity with regard to the acrylamide groups (i.e., having a molecular structure with combinations of a primary OH group, a secondary OH group, or a tertiary OH group, but avoiding two or more primary OH groups, two or more secondary OH groups, or two or more tertiary groups on a single molecule).
  • the polyol includes one primary OH group and one secondary OH group, examples of which include propylene glycol (1,2-propanediol), 1,3-butanediol, 1,2-octanediol, 2-methyl-2,4-pentanediol, and 2,2,4-trimethyl-l,3-pentanediol.
  • An example of a suitable polyol having a combination of a primary, secondary, and tertiary alcohol is 3-methyl-l,2,3-hexanetriol.
  • the entire alcohol content of the solvent consists of one or more of the polyols characterized above, but some mono-alcohol may be included without detracting significantly from the advantages of the present invention.
  • Other non-alcohol solvents may be mixed with the polyol. Examples of non-alcoholic solvents that may be used with the polyols include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Moderate levels of water-insoluble solvents such as toluene or xylene may also be used.
  • the polyols having OH groups of different reactivity as described above comprise at least 5 percent by weight of the total solvent used during the vinyl addition copolymerization, preferably at least 20 percent, most preferably at least 50 percent.
  • Copolymers without acrylic acid in the monomer charge can be made without the gelation problem.
  • polyols with two primary OH groups should be avoided.
  • the copolymerizations which were carried out in polyols having two primary OH groups gelled the most rapidly, it was found that polyols in which the hydroxyl groups were both secondary also presented gelation problems. What was found to be required to successfully produce the desired reaction products without gelling was to use polyols having OH groups of unequal reactivity (e.g., one primary OH and one secondary OH).
  • the amine-defunctionalized epoxy component of the coating formulation of the present invention may be prepared by reacting a polyepoxide resin with ammoma or an amine having at least two active hydrogen atoms.
  • the polyepoxide resin useful herein is a compound or a mixture of compounds having more than 1.0 epoxy groups per molecule.
  • polyepoxides are the polyglycidyl ethers of polyphenols, such as bisphenol A. These are produced by etherification of a polyphenol with epichlorohydrin in the presence of an alkali.
  • the phenolic compound can be 2,2-bis(4-hydroxyphenyl)propane;
  • polyglycidyl ethers of polyhydric alcohols which are derived from such polyhydric alcohols as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerol, and 2,2-bis(4- hydroxycyclohexy l)propane .
  • Cycloaliphatic polyepoxide resins can also be used. Such resins are prepared by epoxidation of cyclic olefins with organic peracids (e.g. peracetic acid).
  • addition polymerization polymers containing pendent epoxy groups may be utilized in this invention.
  • Such polymers are made by copolymerizing a wide variety of polymerizable vinyl monomers including monomers such as glycidyl acrylate and glycidyl methacrylate.
  • Suitable vinyl monomers include those which do not contain a group reactive with the epoxy group and preferably include the alpha, beta- ethylenically unsaturated carboxylic acid esters of saturated alcohols containing from 1 to 8 carbon atoms and the monovinyl aromatic monomers of the benzene class, e.g., styrene and vinyl toluene.
  • the polyepoxide resin is reacted with ammoma or an amine having at least 2 active hydrogen atoms.
  • the active hydrogen atoms can be on the same nitrogen atom (e.g., the primary amines) or on different nitrogen atoms in a compound (e.g., di- or poly amines), wherein the active hydrogen atoms 5 can be on the same nitrogen atom, or on two or more nitrogen atoms.
  • primary amines include ethylamine, propylamine, isopropylamine and butylamine.
  • poly amines examples include hydrazine, ethylene diamine, propylene diamine, butylene diamine, hexylene diamine, diethylene triamine, tetraethylene pentamine, N-methylethylene diamine, N-methylbutylene diamine, N,N-dimethylethylene o diamine, N,N-dipropylethylene diamine, and N,N-dimethylhexylene diamine.
  • ammoma or monoethanolamine are used either separately or in any combination, most preferably ammoma.
  • the ammonia is used in solution as ammonium hydroxide.
  • the reaction of the polyepoxide resin with the ammonia or amine s involves a ring opening reaction where the resultant ungelled product is the amine- terminated product of a polyepoxide resin. It is desired that substantially all of the 1 ,2-epoxy groups contained in the polyepoxide resin be reacted with the ammoma or amine. For this reason, a molar excess of the ammonia or amine to epoxy groups in the epoxy defunctionalization reaction is typically used. The excess may 0 be expressed as a ratio of epoxy groups to primary amine groups of 1:1.5 to 1:6. Larger excesses may be employed, but are not preferred due to excessive release of ammonia or amine.
  • ratios from 1.5:1 to 1:1.5 may be used.
  • the o preferred ratios range from between 1.3:1 to 1:1.3.
  • the reaction of the polyepoxide resin with the ammoma or amine occurs over a wide range of temperatures, preferably from 30°C to 100°C.
  • the time of reaction varies according to the temperature used in the reaction.
  • the reaction of the polyepoxide resin with the ammonia or amine is carried out under controlled conditions in order to avoid gelation without requiring undue amounts of thinning with organic solvent that would need to be removed subsequently.
  • reaction between the epoxy and the amine is carried out at relatively low temperatures (below 60 °C) over a relatively long period of time (at least one hour). It is believed that, under these reaction conditions, it is substantially only primary amines that are reacted.
  • a solvent or mixture of solvents is preferably included in the reaction of the epoxy resin and ammonia or amine for the purpose of achieving better reaction control.
  • Any nonreactive solvent can be used, examples of which include the ketones and alcohols.
  • the product can be diluted to suitable viscosity with addition solvent, examples of which include: methyl ethyl ketone, methyl butyl ketone, xylene, ethanol, propanol, isopropanol, butanol, butyl ether of ethylene glycol, and propylene glycol.
  • the coating compositions of the preferred embodiments comprise resinous blends having from about 5 percent to about 95 percent, preferably from about 20 percent to about 75 percent of the vinyl addition resin and from about 5 percent to about 95 percent, preferably from about 20 percent to about 75 percent of the modified or defunctionalized epoxy resin.
  • the solids content of the compositions range from about 20 percent to about 60 percent with the balance of the composition comprising water, organic solvent, or a mixture of water and organic solvent. Compositions wherein water is the major liquid carrier are preferred.
  • the resinous blends are prepared from the aforedescribed vinyl addition resins and modified or defunctionalized epoxy resins in alternative ways. In one alternative, the vinyl addition resins and modified or defunctionalized epoxy resins are separately made.
  • the acid group containing vinyl addition copolymer is at least partially neutralized with a base either before or after blending with the modified or defunctionalized epoxy resin, and subsequently water is added to form the coating composition.
  • the bases useful herein can be organic or inorganic.
  • Illustrative examples of the bases are ammonia, monoalkylamines, dialkylamines, or trialkylamines such as ethylamine, propylamine, dimethylamine, dibutylamine and cyclohexylamine; monoalkanolamine, dialkanolamine or trialkanolamine such as ethanolamine, diethanolamine, triethanolamine, propanolamine, diisopropanolamine, dimethylethanolamine and diethylethanolamine; morpholine; and inorganic hydroxides such as potassium and sodium hydroxide.
  • the pH of the final aqueous dispersion is adjusted to 7 to 10, preferably less than 9.
  • the percent of neutralization is such as would make the resinous blends water- dispersible.
  • the resinous blend may be partially neutralized from 20 percent up to 95 percent based on acid groups in the vinyl addition copolymer. Additional improvements to coating application latitude have been found from partially neutralizing the carboxyl group content of the resin blend. For example, the improvements to coating application latitude of the present invention have been found from partially neutralizing the carboxyl group content of the resin blend less than 65 percent, preferably less than 50 percent (based on acid groups in the vinyl addition copolymer).
  • An alternative way to prepare the resinous blends comprises blending the vinyl addition resin with the polyepoxide resin and then reacting the epoxide groups with ammonia or amine. It is often desirable in order to get a more durable film to add an external crosslinking agent to the above-described coating compositions. Examples thereof include the aminoplast resins, phenoplast resins, and isocyanates, preferably blocked poly isocyanates.
  • the level of crosslinking agent used as part of the film- forming resin may range up to about 40 percent, and is preferably from about 5 percent to about 20 percent of the film-forming resin.
  • While vinyl addition resins derived from N-(alkoxymethyl)methacrylamide and N-(alkoxymethyl)acrylamide are capable of crosslinking without an external crosslinking agent, such as agents may be added.
  • Aminoplast resins are the condensation products of an aldehyde (e.g. , formaldehyde, acetaldehyde, crotonaldehyde and benzaldehyde), with an amino- or amido group-containing substance (e.g., urea, melamine and benzoguanamine). Products obtained from the reaction of alcohols and formaldehyde with melamine, urea or benzoguanamine are preferred in the aqueous-based coating compositions because of their good water dispersibility.
  • an aldehyde e.g. , formaldehyde, acetaldehyde, crotonaldehyde and benzaldehyde
  • an amino- or amido group-containing substance e.g.,
  • Useful alcohols used to make the ether ified products are the monohydric alcohols, such as methanol, ethanol, propanol, butanol, hexanol, benzyl alcohol, cyclohexanol, and ethoxy ethanol.
  • Etherified melamine-formaldehyde resin is the preferred aminoplast resin.
  • Phenolic resins include the condensation product of an aldehyde with a phenol. Formaldehyde and acetaldehyde are preferred aldehydes.
  • Various phenols can be used (e.g., phenol, cresol, p-phenylphenol, p-tert-butylphenol, p- tert-amylphenol and cyclopentylphenol).
  • blocked polyisocyanates are satisfactory crosslinking agents. These agents are well known in the art. Generally, the organic polyisocyanates are blocked with a volatile alcohol, epsilon-caprolactam or ketoxime. These blocked polyisocyanates become unblocked at elevated temperatures (e.g., above about 100°C).
  • the coating compositions of this invention may contain other optional components such as pigments, fillers, anti-oxidants, flow control agents, surfactants and the like.
  • the coatings of the present invention have been found to possess particular advantages when utilized on high speed roll coating lines for coating sheet aluminum stock intended for containers, but the coatings could be applied onto any substrate, particularly metallic substrates, by any conventional process.
  • the coatings may also be adapted for electrodeposition. Typically, the coatings are cured at elevated temperatures on the order of 200°C to 300°C.
  • Examples Al through A17 disclose vinyl addition copolymerization procedures using a variety of alcohol solvents. The results reported in Table 1 demonstrate the effect of these solvent choices on molecular weight on Examples Al through A14.
  • Examples Al through A10 and A12 through 14 copolymerization of the same monomer mixture of 27.5% N-(butoxymethyl)acrylamide (NBMA), 10% butyl acrylate, 50% styrene and 12.5% acrylic acid was carried out in various dihydroxy functional alcohols.
  • N-(butoxymethyl) acrylamide was replaced with butyl methacrylate for comparison.
  • Example A15 the methly ethyl ketone was replaced with propylene glycol; in Example A16 it was replaced with a propyl ether of propylene glycol; and in Example A17 it was replaced with a butyl ether of propylene glycol. All the reaction conditions were kept constant including temperature which was adjusted by adding methyl ethyl ketone.
  • Example El a modified epoxy resin is disclosed which may be blended with the vinyl addition copolymers.
  • Examples Dl through D5 disclose making dispersions of several of die vinyl addition copolymers of Examples A1-A14 blended with the modified epoxy resin of Example El . These dispersions were then incorporated into coating formulations as set forth in Examples FI through F5.
  • Examples D6 through D9 disclose making dispersions of the vinyl addition copolymer of Example Al blended with the modified epoxy resin of Example El. These dispersions were neutralized with varying amounts of amine, and were then incorporated into coating formulations as set forth in Examples F6 through F9.
  • Examples D10 through D14 disclose making dispersions of several of the vinyl addition copolymers of Examples Al, A2 and A15-A17 blended with the modified epoxy resin of Example El. These dispersions were then incorporated into coating formulations as set forth in Examples F10 through F15.
  • the coating formulations of Examples FI through F9 were tested for coating application latitude. The observed the results are set forth in Table 2.
  • the coating formulations of Examples F10 through F15 were tested for adhesion by Crosshatch tape test and evaluated for blush, discoloration, blistering and loss of adhesion. These observed results are set forth in Table 3.
  • Shellmax wax is a refined petroleum wax of long chain saturated hydrocarbon molecules available from Shell Chemical Company. It is 100 percent solids.
  • the flask charge was taken into a 5 liter round bottom flask equipped with stirrer, dropping funnel, thermometer, condenser and a nitrogen inlet. The mixture was heated to reflux at 140°C. The monomer and initiator charges were fed simultaneously to the reaction mixture over a period of 4 hours. Upon completion of these additions, the initiator (scavenger) charge was added in three equal portions. After each addition, the reaction mixture was held for 1.5 hours. The resulting product was cooled below 60°C, followed by the addition of thinning solvent. The product was stored at room temperature.
  • reaction product was gelled during the addition of monomer and initiator feeds.
  • EXAMPLE A 7 Same as example Al , except that propylene glycol was replaced with DPG (dipropylene glycol). Analysis: The reaction product was extremely viscous after the addition of 2/3 of d e initiator scavenger feed, and gelled during the hold period.
  • EXAMPLE A 17 Same as example Al , except that methyl ethyl ketone was replaced with Propasol ® B (butyl ether of propylene glycol available from Union Carbide) in the thinning charge. Analysis: theoretical solids 46%, viscosity 5380 centipoises.
  • EXAMPLE E 1 A modified epoxy functional resin, was prepared as follows:
  • Methyl ethyl ketone 703.0 Butanol 326.2 *EPON® 828 is a epoxy functional resin (epoxy equivalent weight 188) available from Shell Chemical Company.
  • the charge 1 was taken into a 5 liter flask and heated to 105-110°C. The contents of the flask were held at this temperature for 30 minutes or until dissolved. When dissolved, charge 2 was added, and the mixmre was heated to 135 °C. The reaction mixmre was then allowed to exotherm to 160-190°C and then held for 1.5 hour at 160°C. Following the hold period, the product was allowed to cool to 90°C. Charge 3 was added and the product was cooled and stored at room temperature.
  • the polymerized epoxy resin had epoxy equivalent weight of about 1450, and theoretical solids of 65 % .
  • Charge 1 was taken into a 5 liter round bottom flask, and heated to 35-37°C.
  • Charge 2 was then added sub-surface over 15 minutes.
  • the contents of the flask were heated to 55°C over 30 minutes and held at this temperature for 2 hours.
  • the excess ammonia and some solvents from the modified epoxy were distilled while keeping the temperature below 90°C.
  • Charge 3 was then added to d e flask, and the contents were mixed for 30 minutes. Some solvents of the acrylic polymer were distilled by heating the contents to 110°C.
  • Charge 4 was then added, and die contents were held for 15 minutes.
  • Charges 4 and 5 were added over 90 and 120 minutes, respectively.
  • the product was cooled and stored at room temperature.
  • the reaction product had a solids content of 42%, viscosity of 1240 centipoises (Brookfield viscometer with number 4 spindle at 20 rpm), pH of 8.51, particle size of about 5800 A, and 43.5% of d e acidic groups were neutralized wid dimethy lethanolamine .
  • Example D3 Same as Example D3, except that the acrylic polymer of Example Al was replaced with the acrylic polymer of Example A2 (butyl Carbitol ® solvent). Analysis: the resulting polymeric dispersion had a particle size of 11,900 A and solids content of 42 % .
  • Example D3 Same as Example D3, except that the acrylic polymer Al was replaced with acrylic polymer A3 (Propasol ® B solvent).
  • the resulting polymeric dispersion had particle size of 4010 A, pH of 8.7, viscosity of 596 centipoises, and solids content of 42% .
  • Example D 5 Same as Example D3, except that the acrylic polymer Al was replaced with acrylic polymer A4 (Propasol ® P solvent).
  • the resulting polymeric dispersion had particle size of 4270 A, pH of 8.55, viscosity of 790 centipoises, and solid contents of 42%.
  • Example D3 Same as Example D3, except that the acrylic polymer Al was replaced with acrylic polymer A12 (with 1,3-butanediol used as d e solvent).
  • the resulting polymeric dispersion had a particle size of 4,170 A, pH of 8.25, viscosity of 1,640 centipoises, and solids content of 42% .
  • the resulting polymeric dispersion had particle size of 3900 A, pH of 8.9, viscosity of 3590 centipoises, and solids contents of 42% .
  • the resulting polymeric dispersion had particle size of 5400 A, pH of 8.65, viscosity of 2290 centipoises, and solids contents of 42% .
  • the resulting polymeric dispersion had particle size of 9,660 A, pH of 8.3, viscosity of 500 centipoises, and solids content of 42% .
  • Charge 1 was taken in to a 5 liter round bottom flask, and heated to 35-37°C.
  • Charge 2 was then added sub-surface over 15 minutes.
  • the contents of the flask were heated to 55°C over 30 minutes and held at tiiis temperature until the epoxy equivalent became infinite (4 to 6 hours).
  • Charge 3 was then added to die flask, and d e contents were mixed for 30 minutes, followed by die addition of Charge 4.
  • Charge 5 was added over 2 hours, followed by die addition of charge 6.
  • the reaction mixmre was then heated to reflux and 300 grams of solvents were distilled off. The product was cooled below 40 °C and stored at room temperature.
  • reaction product had a theoretical solids content of 42%, viscosity of 1890 centipoises, pH of 8.59, particle size of about 4040 A. 39.0% of the acidic groups were neutralized with dimethy lethanolamine.
  • Example D10 a small excess of ammonia was again employed (epoxy to ammonia equivalent ratio of 1:1.5).
  • the dispersion was prepared in die same way as in Example D10, except that the polymer of Charge 3 was replaced with d e product of Example A15.
  • the resulting polymeric dispersion was unstable, and separated into two layers.
  • the epoxy to ammonia equivalent ratio was 1 : 1 in accordance widi the preferred practice of die present invention.
  • the dispersion was prepared in the same way as in die example D10, except that the amount of ammonium hydroxide was reduced to 36.4 grams and the polymer of Charge 3 was replaced with the product of Example A2.
  • the resulting polymeric dispersion had particle size of 6100 A, viscosity of 995 centipoises, pH of 7.85 and dieoretical solids of 42% .
  • the epoxy to ammonia equivalent ratio was 1 : 1 in accordance with the preferred practice of the present invention.
  • the dispersion was prepared in die same way as in Example D12, except that the polymer of Charge 3 was replaced by the product of Example A16.
  • the resulting polymeric dispersion had viscosity of 800 centipoises, pH of 7.9, and solids of 39.2% .
  • EXAMPLE D 14 In this example the epoxy to ammoma equivalent ratio was 1:1 in accordance wid die preferred practice of the present invention.
  • the dispersion was prepared in the same way as in Example D12, except that die polymer of Charge 3 was replaced by the product of Example A17.
  • the resulting polymeric dispersion had viscosity of 1090 centipoises, pH of 8.0, and solids content of 39.0% COMPARATIVE DISPERSIONS
  • the polymeric dispersions described in Examples Dl through D14 were combined with additional film formers, such as phenolic resins and/or urea- formaldehyde resins, and water to produce coating formulations FI through F15.
  • additional film formers such as phenolic resins and/or urea- formaldehyde resins
  • the amount of die additional film formers used is not critical, but typically each may be present in amounts of 0-3% by weight on a resin solids basis.
  • the urea-formaldehyde resin is "Beetle 80” an etherified, butylated urea-formaldehyde from American Cyanamid
  • the phenolic resin is "Uravar FB209,” a 57% solids solution in butanol and toluene from DSM Resins.
  • Phenolic resin solution 66 Phenolic resin solution 66
  • Epoxy-acrylic dispersion (Example D3) 2,501
  • Phenolic resin solution 62 Phenolic resin solution 62
  • Epoxy-acrylic dispersion (Example D5) 2556
  • Phenolic resin solution 62 Phenolic resin solution 62
  • Epoxy-acrylic dispersion (Example D7) 2,555
  • Epoxy-acrylic dispersion (Example D13) 168.2
  • Epoxy-acrylic dispersion (Example D14) 169.3
  • the application characteristics for each formulation FI through F9 were evaluated using a Gasway Corporation lab coater (Model RPP044) and a Grieve Corporation high velocity oven (Model VA-1000).
  • the lab coater was set ⁇ up with a stainless steel pick-up roll and a urethane rubber covered applicator roll, botii 8 inches in diameter. These rolls were operated in a typical two roll reverse mode.
  • the line speed of the lab coater was typically 150-165 meters per minute.
  • the application roll speed was typically 150-170 meters per minute; and the pick-up roll speed was typically 30-60 meters per minute.
  • the oven temperature was typically 260-288°C, with dwell time of 10-15 seconds.
  • Formulation FI through F9 were each filtered into a reservoir, the pick-up roll was partially submerged in the reservoir, and the motor driving the applicator and pick-up rolls was started.
  • a 0.019 gauge (0.48 millimeter thick) aluminum panel (5182H19 alloy with A272A pretreatment from Aluminum Company of America) was attached to a stainless steel belt which acted as me line. The line was started at the above-stated speed, and d e coating was applied to the aluminum panel. The coated aluminum panel was ien quickly transferred into the high velocity oven and cured. After cooling, the film weight per 4 square inches (25.8 square centimeters) was then determined and die film was examined for any sign of defects such as solvent blistering or air entrapment.
  • Example F10 through F15 were adjusted to a common solids content of 40% and applied by wire- wound drawdown bar to commercially pretreated aluminum sheet stock. To increase the severity of the test, these coatings were applied onto non-pretreated aluminum substrate. Cure was accomplished in a gas-fired oven by baking the panels to a 465°F (240°C) peak metal temperature. Each coated panel was then sealed in a container filled with Gatorade® sports drink and processed for one hour in a steam retort at 250°F (121 °C). The panels were then evaluated for adhesion by die Crosshatch tape test and evaluated for blush, discoloration, blistering, and loss of adhesion.
  • the Crosshatch tape adhesion test was carried out as follows: The coating was scribed with eleven parallel cuts through the film approximately 1/16 inch (1.6 millimeters) apart. Eleven similar cuts are made at 90 degrees to and crossing the first eleven cuts. Adhesive tape is applied over the area of cuts by pressing down firmly against the coating to eliminate voids and air pockets. Then the tape is sharply pulled off at a right angle to the plane of the coated surface. Adhesion is reported as the percentage of squares remaining on the substrate in the scribed area. For comparison purposes, the same test was performed with a commercially available vinyl resin based coating formulation (Comparative Formulation) which is an industry standard coating for aluminum can end stock. The comparative coating was applied onto a pretreated aluminum substrate, which would be expected to yield better adhesion and blush results than an untreated substrate. The results are reported in Table 3.
  • Comparative Formulation is an industry standard coating for aluminum can end stock.
  • the comparative coating was applied onto a pretreated aluminum substrate, which would be expected to yield better adhesion and

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
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Abstract

L'utilisation d'une formulation contenant une résine pouvant être mise en dispersion dans l'eau permet d'accroître les possibilités d'application de revêtements, et d'améliorer en particulier leur résistance à la formation de cloques. Cette résine comprend le produit de la réaction de copolymérisation de monomères vinyliques obtenus par addition, tels qu'un monomère renfermant un groupe acide, un monomère de N-(alcoxyméthyl)acrylamide ou de N-(alcoxyméthyl)méthacrylamide et au moins un autre monomère vinylique. La réaction a lieu en présence d'un solvant contenant un polyol, les groupes OH de la molécule de polyol présentant une réactivité inégale. Le copolymère peut être mélangé à une résine époxy modifiée avec une amine afin de former une composition de revêtement. Des résultats similaires peuvent être obtenus avec une formulation de revêtement comprenant une résine pouvant être mise en dispersion dans l'eau, ladite résine contenant le produit de la réaction de copolymérisation par addition de monomères vinyliques, tels qu'un monomère renfermant un groupe acide, et au moins un autre monomère vinylique mélangé à une résine modifiée avec une amine. Les groupes acides présents dans le copolymère de vinyle obtenu par addition n'ont été que partiellement neutralisés lors de la mise en dispersion aqueuse. Des résines époxy défonctionnalisées avec une amine, utilisées dans des formulations de revêtements, améliorent la résistance à la formation de voile et de taches si les rapports de réaction entre équivalents groupe époxy et équivalents amine primaire ou ammoniac sont proches de 1:1.
EP95914213A 1994-03-29 1995-03-29 Compositions de revetement vinylique en phase aqueuse a base de melanges de resines, et leurs utilisations Withdrawn EP0753018A1 (fr)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
US219603 1988-07-15
US21960194A 1994-03-29 1994-03-29
US21932294A 1994-03-29 1994-03-29
US219601 1994-03-29
US219322 1994-03-29
US08/219,603 US5428084A (en) 1994-03-29 1994-03-29 Defunctionalized epoxy resins useful in coatings
PCT/US1995/003893 WO1995026373A1 (fr) 1994-03-29 1995-03-29 Compositions de revetement vinylique en phase aqueuse a base de melanges de resines, et leurs utilisations

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DE19650157A1 (de) 1996-12-04 1998-06-10 Basf Coatings Ag Verfahren zur Beschichtung von Substraten, vorzugsweise aus Metall
DE102010012047A1 (de) 2010-03-19 2011-09-22 Basf Coatings Gmbh Verfahren zur Beschichtung eines Metall- oder Kunststoffsubstrats, daraus erhältliche Beschichtung und beschichtetes Substrat

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DE4141693A1 (de) * 1991-12-18 1993-07-01 Roehm Gmbh Verfahren zur herstellung einer wasserloeslichen polymersuspension

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JP3472281B2 (ja) 2003-12-02
KR970702303A (ko) 1997-05-13
JPH09511008A (ja) 1997-11-04
KR100374528B1 (ko) 2003-05-09
JP3321171B2 (ja) 2002-09-03
WO1995026373A1 (fr) 1995-10-05
JP2002121262A (ja) 2002-04-23

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