WO2014099582A1 - Procédé de préparation d'une composition de revêtement en poudre - Google Patents

Procédé de préparation d'une composition de revêtement en poudre Download PDF

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Publication number
WO2014099582A1
WO2014099582A1 PCT/US2013/074580 US2013074580W WO2014099582A1 WO 2014099582 A1 WO2014099582 A1 WO 2014099582A1 US 2013074580 W US2013074580 W US 2013074580W WO 2014099582 A1 WO2014099582 A1 WO 2014099582A1
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WO
WIPO (PCT)
Prior art keywords
polyurethane resin
powder coating
coating composition
powder
hydroxy
Prior art date
Application number
PCT/US2013/074580
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English (en)
Inventor
Carmen Flosbach
Stefanie Matten
Jennifer Donnermeyer
Original Assignee
Axalta Coating Systems IP Co. LLC
Coatings Foreign Ip Co. Llc
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
Application filed by Axalta Coating Systems IP Co. LLC, Coatings Foreign Ip Co. Llc filed Critical Axalta Coating Systems IP Co. LLC
Publication of WO2014099582A1 publication Critical patent/WO2014099582A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
    • C08G18/3203—Polyhydroxy compounds
    • C08G18/3206—Polyhydroxy compounds aliphatic
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
    • C08G18/3203—Polyhydroxy compounds
    • C08G18/3212—Polyhydroxy compounds containing cycloaliphatic 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/61—Polysiloxanes
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/6505—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen the low-molecular compounds being compounds of group C08G18/32 or polyamines of C08G18/38
    • C08G18/6511—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen the low-molecular compounds being compounds of group C08G18/32 or polyamines of C08G18/38 compounds of group C08G18/3203
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/73—Polyisocyanates or polyisothiocyanates acyclic
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/81—Unsaturated isocyanates or isothiocyanates
    • C08G18/8141—Unsaturated isocyanates or isothiocyanates masked
    • C08G18/815—Polyisocyanates or polyisothiocyanates masked with unsaturated compounds having active hydrogen
    • C08G18/8158—Polyisocyanates or polyisothiocyanates masked with unsaturated compounds having active hydrogen with unsaturated compounds having only one group containing active hydrogen
    • C08G18/8175—Polyisocyanates or polyisothiocyanates masked with unsaturated compounds having active hydrogen with unsaturated compounds having only one group containing active hydrogen with esters of acrylic or alkylacrylic acid having only one group containing active hydrogen
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/16—Catalysts
    • C08G18/22—Catalysts containing metal compounds
    • C08G18/24—Catalysts containing metal compounds of tin
    • C08G18/244—Catalysts containing metal compounds of tin tin salts of carboxylic acids
    • C08G18/246—Catalysts containing metal compounds of tin tin salts of carboxylic acids containing also tin-carbon bonds
    • 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
    • C08G2150/00—Compositions for coatings
    • C08G2150/20—Compositions for powder coatings

Definitions

  • the present invention refers to a process for preparation of a powder coating composition useful for coatings providing improved flow.
  • polyurethane resins are known to the person skilled in the art; in particular, they may be produced by reacting polyol(s) with polyisocyanate(s).
  • compositions e.g. powder coating compositions.
  • the present invention relates to a process for preparation of a
  • powder coating composition comprising 0.1 to 5 wt% of at least one polyurethane resin, the wt% are based on the total weight of the powder coating composition, wherein the at least one polyurethane resin is produced from an isocyanate component and an alcohol component comprising at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane, wherein the at least one polyurethane resin having a silicon content (calculated as elementary silicon with molecular mass 28) in a range of 5 to 35 wt%, the wt% are based on the weight of the polyurethane resin, wherein the at least one polyurethane resin is produced by reacting the isocyanate component and the alcohol component comprising the at least one ⁇ , ⁇ -hydroxy organo functional
  • polydimethylsiloxane with one another in substance or in the presence of a solvent and/or water.
  • the powder coating composition according to the invention based on the at least one polyurethane resin provides coatings with highly improved flow properties.
  • the present invention refers to a powder coating composition
  • a powder coating composition comprising 0.1 to 5 wt% of at least one polyurethane resin, the wt% are based on the total weight of the powder coating composition, wherein the at least one polyurethane resin is produced from an isocyanate component and an alcohol component comprising at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane, and wherein the at least one polyurethane resin having a silicon content (calculated as elementary silicon with molecular mass 28) in a range of 5 to 35 wt%, the wt% are based on the weight of the polyurethane resin.
  • the powder coating composition of the invention comprises 0.2 to 3 wt% of the at least one polyurethane resin, the wt% are based on the total weight of the powder coating composition, wherein the at least one polyurethane resin is produced from an isocyanate component and an alcohol component comprising at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane, and wherein the at least one polyurethane resin having a silicon content (calculated as elementary silicon with molecular mass 28) in a range of 5 to 35 wt%, the wt% are based on the weight of the polyurethane resin.
  • the at least one polyurethane resin according to this invention can be selected from the group consisting of amorphous, crystalline and/or semi-crystalline polyurethane resins.
  • the at least one polyurethane resin according to this invention is selected from the group consisting of crystalline and/or semi-crystalline polyurethane resins.
  • Amorphous substances can be defined by glass transition temperatures (Tg), and crystalline and/or semi-crystalline substances can be defined by melting temperatures (Tm).
  • Tg is the glass transition temperature of the solid component(s) measured by means of differential scanning calorimetry (DSC) according to ISO 11357-2 standard.
  • Tm is the melting temperature of the solid component(s) measured by means of DSC at heating rates of 10 K/min according to DIN 53765-B-10 standard.
  • the melting temperature is not in general a sharp melting point, but instead the upper end of melting range with a breadth.
  • the at least one polyurethane resin of the invention may have a number-average molar mass (Mn) in the range of, for example, 500 to 15000, preferably 1000 to 12000.
  • the number-average molar mass (Mn) stated herein is the number average molar mass determined or to be determined by gel permeation chromatography (GPC; divinylbenzene-cross-linked polystyrene as the immobile phase, tetrahydrofuran as the liquid phase, polystyrene standards) determined according to ISO 13885-1 standard.
  • GPC gel permeation chromatography
  • the at least one polyurethane resin of the invention may be non- functional, or may have functional groups such as hydroxyl, carboxyl, alkoxy, (meth)acryl, blocked isocyanate groups and/or may have free-radically polymerizable olefinic double bonds in the form of (meth)acryloyl within its resin structure.
  • the polyurethane resin of the invention carries functional groups.
  • the functional groups and/or free-radically polymerizable olefinic double bonds of the polyurethane resin of the invention are able to cross-link with the functional groups of the further components of the powder coating composition, particularly of the binder resins and/or of the cross-linking (curing) agents, to provide the powder coating composition of the invention a highly improved flow effect.
  • (meth)acryloyl groups can be introduced by transesterifying hydroxy functional polyurethane resin with alkyl esters of (meth)acrylic acid; esterifying hydroxy functional polyurethane resin with (meth)acrylic acid; reacting hydroxyl functional polyurethane resin with isocyanate-functional (meth)acrylates or reacting carboxy functional polyurethane resin with epoxy-functional (meth)acrylates, reacting isocyanate functional polyurethane resin with hydroxyalkyl (meth)acrylates.
  • the hydroxyl groups may be introduced using measures known to the person skilled in the art, for example, by reacting isocyanate groups still present in the polyurethane resin with polyols.
  • (meth)acryloyl is respectively intended to mean acryloyl and/or methacryloyl.
  • (meth)acryl is respectively intended to mean acryl and/or methacryl.
  • the at least one polyurethane resin of the invention may have a hydroxyl number in the range of, for example, 30 to 150 mg KOH/g resin, preferably 30 to 120 mg KOH/g resin.
  • the carboxyl functional polyurethane resin of the invention may have an acid number in the range of, for example, 30 to 150 mg KOH/g resin, preferably 30 to 120 mg KOH/g resin.
  • the at least one polyurethane resin of the invention may have a number of blocked isocyanate groups NCO, calculated as latent NCO-content in a range of 5 to 15, preferably 5 to 10.
  • the latent NCO-content stated herein is the grams of free isocyanate groups NCO (NCO calculated with molecular mass 42) after deblocking, per lOOg resin.
  • the isocyanate groups are incorporated in blocked form. Blocking may proceed as known in the art with conventional agents, e.g., with monoalcohols, glycol ethers, ketoximes, lactams, malonic acid esters, acetoacetic acid esters, for example, ethylene glycol monobutyl ether, butanone oxime, phenol, ethyl acetoacetate, dimethylpyrazole or caprolactam.
  • the hydroxyl number stated herein is defined as the number of mg of potassium hydroxide (KOH) which is equal to the number of milligrams (mg) acetic acid for acetalizing of 1 g of the resin, determined according to DIN 53240 standard.
  • the acid number stated herein is defined as the mg of potassium hydroxide required to neutralise the acid groups of the polyester, described in DIN EN ISO 21 14 standard.
  • the isocyanate component for the production of the polyurethane resin of this invention comprises isocyanate(s) as known by a skilled person for the production of polyurethanes.
  • isocyanate(s) as known by a skilled person for the production of polyurethanes.
  • diisocyanates such as 1,6-hexane diisocyanate,
  • tetramethylxylylene diisocyanate isophorone diisocyanate
  • the isomeric diphenylmethane diisocyanates dicyclohexylmethane diisocyanate and cyclohexane diisocyanate
  • polyisocyanates derived from these diisocyanates like for example, uretidione or isocyanurate type polyisocyanates produced by di- or trimerization of these diisocyanates or polyisocyanates produced by reaction of these diisocyanates with water and containing biuret groups or urethane group containing polyisocyanates produced by reaction of these diisocyanates with polyols.
  • Preferred examples of the isocyanate component are isophorone diisocyanate, 1,6-hexane diisocyanate and dicyclohexylmethane diisocyanate.
  • the alcohol component for the production of the polyurethane resin of this invention comprises the at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane in a content providing the polyurethane resin of the invention a silicon content (calculated as elementary silicon with molecular mass 28) in a range of 5 to 35 wt%, the wt% based on the total weight of the polyurethane resin.
  • the silicon content of the at least one polyurethane resin of the invention in the powder coating composition is provided by the amount of the at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane used for the preparation of the polyurethane resin of the invention.
  • the ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane can be a linear ⁇ , ⁇ - hydroxy organo functional polydimethylsiloxane, for example, linear ⁇ , ⁇ - dihydroxyalkylpolydimethylsiloxane having a hydroxyl number in the range of, for example, 30 to 150, preferably 35 to 120, providing a calculated hydroxy equivalent weight of 375 to 1900, preferably 470 to 1600.
  • the alkyl residue can be, for example, CI to C6 alkyl group.
  • the alcohol component for the production of the polyurethane resin of the invention further comprises alcohols which are diols or polyols in the form of low molar mass compounds defined by empirical and structural formula and/or oligomeric or polymeric polyols with number-average molar masses of, for example, up to 800, for example, corresponding hydroxyl-functional polyethers, hydroxyl-functional polyesters and/or hydroxyl-functional polycarbonates.
  • Examples of such low molar mass diols are ethylene glycol, the isomeric propane- and butanediols, 1,5-pentanediol, 1,6-hexanediol, 1, 10-decanediol, 1, 12- dodecanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, dimer fatty alcohol, neopentyl glycol, butylethylpropanediol, the isomeric cyclohexanediols, the isomeric cyclohexanedimethanols, tricyclodecanedimethanol.
  • polyols are polyols with more than two hydroxyl groups such as glycerol, trimethylolpropane, trimethylolethane and pentaerythrite.
  • Preferred examples of such further diols and polyols are trimethylolpropane and glycerol.
  • the person skilled in the art selects the nature and proportion of the isocyanate component and the alcohol component comprising the at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane for the production of the polyurethane resin of the invention in such a manner providing the polyurethane resin of the invention a silicon content (calculated as elementary silicon with molecular mass 28) in a range of 5 to 35 wt%, the wt% based on the total weight of the polyurethane resin.
  • the isocyanate component and the polyol component comprising the at least one ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane can be reacted with one another in substance or in the presence of a solvent and/or water.
  • solvent means an organic solvent or mixture of organic solvents, as known in the art.
  • solvent may be used, in general, for example, in an amount of 0 to 50 wt%, the wt% based on the total amount of the polyurethane resin solution which, however, makes it necessary to remove the solvent from the resulted resin.
  • the production of the polyurethane resin according to the invention is carried out without solvent and without subsequent purification operations.
  • the reactants may all be reacted together simultaneously or in two or more synthesis stages. When the synthesis is performed in multiple stages, the reactants may be added in the most varied order, for example, also in succession or in alternating manner.
  • the polyol component may be divided into two or more partial amounts, for example, or into the individual polyols, for example, such that the isocyanate component is reacted first with a portion of the polyol component, e.g. ⁇ , ⁇ -hydroxy organo functional polydimethylsiloxane, and finally with the remaining proportion of the polyol component.
  • the isocyanate component may also be divided into two or more partial amounts, for example, such that the polyols are reacted first with a portion of the isocyanate component and finally with the remaining proportion of the isocyanate component. That means, that the individual reactants may be added in their entirety or in two or more portions.
  • the reaction is exothermic and proceeds at a temperature above the melting temperature of the reaction mixture.
  • the reaction temperature is, for example, 60 to 140°C.
  • the rate of addition or quantity of reactants added is accordingly determined on the basis of the degree of exothermy and the liquid (molten) reaction mixture may be maintained within the desired temperature range by heating or cooling.
  • solid polyurethane resin is obtained.
  • the polyurethane resin assumes the form of a mixture exhibiting a molar mass distribution.
  • the polyurethane resin does not, however, require working up and may be used directly in the powder coating composition of the invention.
  • the resulted polyurethane resin may be used in the powder coating composition of the invention in amounts of 0.1 to 5 wt%, preferably 0.2 to 3 wt%, the wt% are based on the total weight of the powder coating composition, in combination with commonly used components of a powder coating composition as known in the art, such as binder resin(s), cross-linking (curing) agent(s) and pigment(s), filler(s) and further coating additive(s).
  • binder resin(s) and cross-linking (curing) agent(s) are compounds known as such in the art of paints and coatings by a skilled person which are different from the polyurethane resin of this invention.
  • the binder resins can also be based on, for example, polyester resins, urethane resins, polyester urethane resins, polyester epoxy resins, epoxy resins, (meth) acrylic resins, alkyd resins and melamine/urea/formaldehyde resins, including polymer hybrid resins derived from these classes of resin binders, with a number-average molar mass (Mn) in the range of, for example, 500 to 10000.
  • Mn number-average molar mass
  • the polyesters may be produced in a conventional manner by reacting of one or more aliphatic, aromatic or cycloaliphatic di- or polycarboxylic acids, and the anhydrides and/or esters thereof with polyalcohols, as is, for example, described in D.A. Bates, The Science of Powder Coatings, volumes 1 & 2, Gardiner House, London, 1990, and as known by the person skilled in the art.
  • (Meth)acrylic resins may include, for example, copolymers prepared from alkyl(meth) acrylates with glycidyl(meth) acrylates and olefinic monomers; functionalized resins such as polyester (meth)acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, glycidyl(meth) acrylates.
  • the binder resin(s) may comprise self-crosslinkable resins containing cross- linkable functional groups known by a person skilled in the art. In this case, no cross- linking (curing) agent needs to be used in the composition according to the invention.
  • the final product can also be cross-linked by using at least one cross-linking (curing) agent suitable for the binder resins as such known by a person skilled in the art.
  • curing agents are blocked cycloaliphatic, aliphatic or aromatic
  • polyisocyanates agents containing epoxy groups, such as, for example, triglycidyl isocyanurate (TGIC); polyglycidyl ethers based on diethylene glycol; glycidyl functionalized (meth) acrylic copolymers; agents containing amino, amido, (meth)acrylate and/or hydroxyl groups, for example hydroxyl alkylamide crosslinker, as well as vinyl ethers.
  • TGIC triglycidyl isocyanurate
  • acrylic copolymers agents containing amino, amido, (meth)acrylate and/or hydroxyl groups, for example hydroxyl alkylamide crosslinker, as well as vinyl ethers.
  • conventionally curing agents such as, dicyanodiamide hardeners, carboxylic acid hardeners or phenolic hardeners are usable.
  • the powder coating composition of the invention may comprise those binder resin(s) and cross-linking (curing) agent(s) in amounts of, for example, 30 to 99.9 wt%, based on the total weight of the powder coating composition of the invention.
  • the powder coating composition of the invention may comprise pigment(s), filler(s) and/or further coating additive(s) known at a skilled person in a range of, for example, 0.5 to 60 wt%, preferably 1 to 60 wt%, based on the total weight of the powder coating composition of the invention.
  • the pigments can be transparent pigments, color-imparting and/or special effect-imparting pigments and/or fillers (extenders).
  • inorganic or organic color-imparting pigments are titanium dioxide, iron oxide pigments, carbon black, azo pigments, phthalocyanine pigments, quinacridone or pyrrolopyrrole pigments.
  • special effect-imparting pigments are metal pigments, for example, made from aluminum, copper or other metals; interference pigments, such as, for example, metal oxide coated metal pigments, for example, titanium dioxide coated or mixed oxide coated aluminum, coated mica, such as, for example, titanium dioxide coated mica.
  • Examples of usable fillers are silicon dioxide, aluminum silicate, barium sulfate, calcium carbonate and talcum.
  • Further coating additives are, for example, inhibitors, catalysts, levelling agents, degassing agents, wetting agents, anticratering agents, initiators, antioxidants and light stabilizers.
  • the coating additives are used in conventional amounts known to the person skilled in the art.
  • the components of the powder coating composition are mixed, extruded and ground by conventional techniques employed in the powder coatings art familiar to a person of ordinary skill in the art. Typically, all of the components of the present powder coating formulation are added to a mixing container and mixed together. The blended mixture is then melt blended, for example, in a melt extruder. Also, components can be melt blended with the molten polyurethane resin. The melt blended, for example extruded, composition is then cooled and broken down and ground to a powder. The ground powder is subsequently screened to achieve the desired particle size, for example, an average particle size (mean particle diameter) of 20 to 200 ⁇ , determined by means of laser diffraction.
  • an average particle size mean particle diameter
  • a predetermined amount of a component of the powder coating components be added, for example, to the further components of the composition, and then premixed.
  • the premix can then be extruded, cooled, and thereafter pulverized and classified.
  • the powder coating composition may also be prepared by spraying from supercritical solutions, NAD "non-aqueous dispersion” processes or ultrasonic standing wave atomization process.
  • specific components of the powder coating composition may be processed with the finished powder coating particles after extrusion and grinding by a "bonding" process using an impact fusion.
  • the specific components may be mixed with the powder coating particles.
  • the individual powder coating particles are treated to softening their surface so that the components adhere to them and are homogeneously bonded with the surface of the powder coating particles.
  • the softening of the powder particles' surface may be done by heat treating the particles to a temperature, e.g., 40 to 100°C, dependent from the melt behaviour of the powder particles.
  • the desired particle size of the resulted particles may be proceed by a sieving process.
  • the powder coating composition of the invention can be readily applied to metallic and non-metallic substrates, in a dry-film thickness of 10 to 300 ⁇ , preferably 20 to 100 ⁇ , particularly from 10 to 50 ⁇ for thin film coatings.
  • the powder coating composition of the invention can be used to coat metallic substrates including, but not limited to, steel, brass, aluminum, chrome, and mixtures thereof, and also to other substrates including, for example, heat-sensitive substrates, such as, substrates based on wood, plastics and paper, and other substrates based, for example, on glass and ceramics.
  • the surface of the substrate may be subjected to a mechanical treatment, such as, blasting followed by, in case of metal substrates, acid rinsing, or cleaning followed by chemical treatment.
  • the powder coating composition of the invention may be applied by, e.g., electrostatic spraying, electrostatic brushing, thermal or flame spraying, fluidized bed coating methods, flocking, tribostatic spray application and the like, also coil coating techniques, all of which are known to those skilled in the art.
  • the substrate Prior to applying the powder coating composition of the invention the substrate may be grounded but not pre-heated, so that the substrate is at an ambient temperature of about 25°C.
  • the substrate to be coated may be pre-heated before the application of the powder coating composition, and then either heated after the application of the powder composition or not.
  • gas is commonly used for various heating steps, but other methods, e.g., microwaves, infra red (IR), near infra red (NIR) and/or ultra violet (UV) irradiation are also known.
  • the pre-heating can be to a temperature ranging from 60 to 260°C using means familiar to a person of ordinary skill in the art.
  • the powder coating composition of the invention can be applied directly on the substrate surface as a primer coating or on a layer of a primer which can be a liquid or a powder based primer.
  • the powder coating composition can also be applied as a coating layer of a multilayer coating system based on liquid or powder coats, for example, as clear coat layer applied onto a color-imparting and/or special effect-imparting base coat layer or as pigmented one-layer coat applied onto a prior coating.
  • the powder After being applied, the powder can be melted by exposing by convective, gas and/or radiant heating, e.g., IR and/or NIR irradiation, as known in the art, to temperatures of, e.g. 100°C to 300°C, preferably, 120°C to 200°C, object temperature in each case, for, e.g., 2 to 20 minutes in case of pre-heated substrates, and, for example, 4 to 30 minutes in case of non-pre-heated substrates.
  • convective, gas and/or radiant heating e.g., IR and/or NIR irradiation
  • the applied and melted powder can be cured by thermal energy.
  • the coating layer may, for example, be exposed to convective, gas and/or radiant heating, e.g., infrared (IR) and/or near infra-red (NIR) irradiation, as known in the art, to temperatures of, e.g., 100 to 300°C, preferably of 120 to 230°C for convective thermal curing and preferably 200 to 280°C for radiation heating processes (object temperature in each case).
  • IR infrared
  • NIR near infra-red
  • Dual curing means a curing method of the powder coating composition according to the invention where the applied powder coating composition can be cured, e.g., both by high energy radiation such as, e.g. ultra violet (UV) irradiation, and by thermal curing methods known by a skilled person as described above.
  • UV radiation ultra violet
  • UV-radiation is the preferred high-energy radiation. Irradiation may proceed continuously or discontinuously.
  • thermally curable powder coating compositions may contain thermally cleavable free-radical initiators
  • the powder coating compositions curable by UV irradiation contain photoinitiators.
  • the initiators can be used, for example, in amounts of 0.1 to 7 wt%, preferably of 0.5 to 5 wt%, based on the total powder coating composition of the invention.
  • the initiators may be used individually or in combination.
  • thermally cleavable free-radical initiators are azo compounds, peroxide compounds and C-C-cleaving initiators, as known by a person skilled in the art.
  • photoinitiators are benzoin and derivatives thereof, acetophenone, benzophenone, thioxanthone and derivatives thereof, anthraquinone, 1- benzoylcyclohexanol, organophosphorus compounds as known by a person skilled in the art.
  • HDI 1,6-hexandiisocyanate
  • thermo couple and column 18.8 wt% of 1,6-hexandiisocyanate (HDI) are mixed with 0.3 wt% of methylhydrochinone and 0.01 wt% dibutyltindilaurate. The mixture is heated to 60 °C, and 12.9 wt% of hydroxyethylacrylate is dosed in such a way that a temperature of 80 °C is not exceeded. The mixture is kept at 80 °C till the target NCO-value is reached. After having reached the target NCO-content 65.
  • HDI 1,6-hexandiisocyanate
  • lwt% of TEGOMER® H-Si 231 1 (commercially available from Tego, a part of Evonik Industries AG) and 2.9 wt% of 1,5-Pentandiol are added one after the other in such a way that a temperature of 120°C is not exceeded. The temperature is kept at 120°C till no NCO-value is detectable. The molten resin is filled off and cooled down.
  • Example 3 and 4 are each applied with a film thickness of 80 ⁇ onto steel panels, molten for 10 min at 140 °C (oven temperature) and after that irradiated with UV-light with an intensity of 500 mW/cm 2 and a UV-dose of 800 mJ/cm 2 .

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Paints Or Removers (AREA)

Abstract

L'invention concerne un procédé de préparation d'une composition de revêtement en poudre comprenant 0,1 à 5 % en poids d'au moins une résine de polyuréthane, le pourcentage en poids étant basé sur le poids total de la composition de revêtement en poudre. La résine de polyuréthane est fabriquée à partir d'un composant isocyanate et d'un composant alcool contenant au moins un polydiméthylsiloxane α,ω-hydroxy organo-fonctionnel. La résine de polyuréthane contient 5 à 35 % en poids de silicium, le pourcentage en poids étant basé sur le poids de la résine de polyuréthane. La résine de polyuréthane est obtenue en faisant réagir le composant isocyanate et le composant alcool contenant ledit polydiméthylsiloxane α,ω-hydroxy organo-fonctionnel l'un avec l'autre en substance ou en présence d'un solvant et/ou d'eau. La composition de revêtement en poudre permet de produire des revêtements dont les propriétés d'écoulement sont extrêmement améliorées.
PCT/US2013/074580 2012-12-17 2013-12-12 Procédé de préparation d'une composition de revêtement en poudre WO2014099582A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108531061A (zh) * 2018-04-12 2018-09-14 太仓中化环保化工有限公司 一种粉末涂料及其制备方法和应用
WO2018195119A1 (fr) * 2017-04-17 2018-10-25 Cornell University Revêtement oléophobe sans fluor, procédés de production de celui-ci et utilisations de celui-ci

Citations (2)

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Publication number Priority date Publication date Assignee Title
DE102004058069A1 (de) * 2004-12-01 2006-06-08 Basf Ag Kratzfeste strahlungshärtbare Beschichtungen
US20070112164A1 (en) * 2005-11-17 2007-05-17 Bayer Materialscience Llc Low surface energy, ethylenically unsaturated polyisocyanate addition compounds and their use in coating compositions

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
DE102004058069A1 (de) * 2004-12-01 2006-06-08 Basf Ag Kratzfeste strahlungshärtbare Beschichtungen
US20070112164A1 (en) * 2005-11-17 2007-05-17 Bayer Materialscience Llc Low surface energy, ethylenically unsaturated polyisocyanate addition compounds and their use in coating compositions

Non-Patent Citations (1)

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Title
D.A. BATES: "The Science of Powder Coatings", vol. 1, 2, 1990, GARDINER HOUSE

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018195119A1 (fr) * 2017-04-17 2018-10-25 Cornell University Revêtement oléophobe sans fluor, procédés de production de celui-ci et utilisations de celui-ci
CN115717337A (zh) * 2017-04-17 2023-02-28 康奈尔大学 无氟防油涂层及其制作方法和用途
CN108531061A (zh) * 2018-04-12 2018-09-14 太仓中化环保化工有限公司 一种粉末涂料及其制备方法和应用

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