EP1165714A1 - Hitzehärtbare pulverzusammensetzungen zum herstellen von beschichtungen mit geringem glanz - Google Patents

Hitzehärtbare pulverzusammensetzungen zum herstellen von beschichtungen mit geringem glanz

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Publication number
EP1165714A1
EP1165714A1 EP99969427A EP99969427A EP1165714A1 EP 1165714 A1 EP1165714 A1 EP 1165714A1 EP 99969427 A EP99969427 A EP 99969427A EP 99969427 A EP99969427 A EP 99969427A EP 1165714 A1 EP1165714 A1 EP 1165714A1
Authority
EP
European Patent Office
Prior art keywords
acid
hydroxyl groups
weight
containing hydroxyl
parts
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Withdrawn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
EP99969427A
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English (en)
French (fr)
Inventor
Luc Moens
Kris Buysens
Daniel Maetens
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.)
UCB SA
Original Assignee
UCB SA
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Filing date
Publication date
Application filed by UCB SA filed Critical UCB SA
Publication of EP1165714A1 publication Critical patent/EP1165714A1/de
Withdrawn legal-status Critical Current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
    • 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
    • C08G18/80—Masked polyisocyanates
    • C08G18/8061—Masked polyisocyanates masked with compounds having only one group containing active hydrogen
    • C08G18/807—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with nitrogen containing compounds
    • C08G18/8074—Lactams
    • 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
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4202—Two or more polyesters of different physical or chemical nature
    • 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
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4205—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups
    • C08G18/4208—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups
    • C08G18/4211—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols
    • C08G18/4219—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols from aromatic dicarboxylic acids and dialcohols in combination with polycarboxylic acids and/or polyhydroxy compounds which are at least trifunctional
    • 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
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4236—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups
    • C08G18/4238—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols
    • C08G18/4241—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols from dicarboxylic acids and dialcohols in combination with polycarboxylic acids and/or polyhydroxy compounds which are at least trifunctional
    • 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
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4244—Polycondensates having carboxylic or carbonic ester groups in the main chain containing oxygen in the form of ether 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
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4266—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from hydroxycarboxylic acids and/or lactones
    • C08G18/4283—Hydroxycarboxylic acid or ester
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • 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

  • Thermosetting powder compositions for the preparation of low gloss coatings are Thermosetting powder compositions for the preparation of low gloss coatings.
  • thermosetting powder compositions comprising as a binder a mixture of a hyperbranched polyol, a polyester containing hydroxyl groups, optionally a semi-crystalline polyester containing hydroxyl groups and a blocked isocyanate as crosslinking.
  • the invention relates to thermosetting powder compositions which, by firing, give coatings of low gloss.
  • the invention also relates to the use of these compositions for the preparation of powder paints and varnishes providing coatings of low gloss, as well as to the coatings obtained from these compositions.
  • low gloss used to qualify the coatings described in this specification means that these coatings have a gloss, measured according to ASTM D523 at 60 °, ranging from 0 to 70%.
  • this term encompasses coatings which can be described as "semi-matt” for glosses ranging from 31 to 70%, or “matt " for glosses ranging from 0 to 30%, according to the same standard.
  • thermosetting compositions in the form of powders are widely used as paints and varnishes for coating the most diverse objects.
  • thermosetting powder compositions have already found a wide outlet in the construction of household appliances, garden furniture, accessories for the automotive industry, etc. They generally contain an organic thermosetting binder, fillers, pigments, catalysts and various additives to adapt their behavior to their use.
  • thermosetting powder compositions There were mainly two types of thermosetting powder compositions; on the one hand, those which contain as a binder a mixture of polymers with carbon groups such as a polyester or a carboxylated polyacrylate and of epoxidized compounds, mainly triglycidyl isocyanurate and, on the other hand, those which contain as binder a mixture of polymers with hydroxyl groups, the most. often a hydroxylated polyester with isocyanates blocked with phenol, caprolactam. by the uretdione, etc.
  • Powder compositions generally give coatings which have good adhesion to the metal substrate (steel or aluminum), good resistance to impact and to solvents, and excellent resistance to weathering.
  • semi-crystalline polyesters have been described, used alone or in admixture with amorphous polyesters, for the preparation of powdered thermosetting compositions. These polyesters contain carboxyl or hydroxyl functions, and they are used with the usual crosslinkers for this type of polyester. This type of composition provides coatings which have a better balance, compared to the amorphous polyesters used alone, of properties such as flexibility and surface equality.
  • one or more specific matting agents such as silica, talc, chalk and metal salts are introduced into the powder composition, in addition to the conventional binder and pigments.
  • the reduction in gloss is often insufficient and there is a marked deterioration in the properties of the paint coatings, for example a lack of adhesion to the metal substrate.
  • waxes for example polyolefin wax and metal salts (for example zinc 2-benzothiazolethiolate)
  • thermosetting powder compositions based on polyesters with terminal carboxyl groups and epoxidized compounds such as triglycidylisocyanurate.
  • European patent application 366,608 describes powder paints obtained by extrusion and providing matt coatings, but two crosslinking agents are used. These powder paints contain an epoxy resin, in particular diglycidyl ether of bisphenol A, a polycarboxylic acid, such as, for example, 2,2,5,5-tetra- ( ⁇ -carboxyethyl) -cyclopentanone as the first crosslinking agent, and a saturated polyester terminated with carboxyl groups, tolylbiguanide or dicyandiamide as the second crosslinking agent.
  • an epoxy resin in particular diglycidyl ether of bisphenol A
  • a polycarboxylic acid such as, for example, 2,2,5,5-tetra- ( ⁇ -carboxyethyl) -cyclopentanone
  • a saturated polyester terminated with carboxyl groups, tolylbiguanide or dicyandiamide as the second crosslinking agent.
  • thermosetting powder compositions comprising at least one semi-crystalline polyester carrying hydroxyl groups, at least one amorphous polyester carrying hydroxyl groups, at least one acrylic copolymer carrying hydroxyl groups and a blocked polyisocyanate as crosslinking agent.
  • the coatings obtained from these compositions have a gloss of less than 35, at an angle of 60 °, good mechanical properties and good pencil hardness.
  • the main disadvantage of the powder paints obtained by extrusion described in the patents cited above is that the conditions Extrusion, such as adjusting the temperatures, the shear gradient, etc., are very critical and make it particularly difficult to obtain a coating having a well reproducible degree of mattness from a well defined composition.
  • the difficulty is to find a composition which produces, under the usual conditions of extrusion, a matt coating in a completely reliable and reproducible manner.
  • thermosetting powder compositions which can provide coatings of low gloss and which do not have the defects of known compositions.
  • thermosetting powder compositions giving coatings of low gloss which are well reproducible and having good mechanical properties and excellent weather resistance without this being necessary to add specific additives to produce the mattness of the coatings, and in a single extrusion.
  • thermosetting powder compositions comprising a mixture of compounds containing hydroxyl groups and of an isocyanate blocked as crosslinking agent, which are characterized in that the mixture comprises: (a) 5 to 50 parts by weight d a hyperbranched polyol, (b) 2.5 to 95 parts by weight of an amorphous polyester containing hydroxyl groups. (c) 0 to 90 parts by weight of a semi-crystalline polyester containing hydroxyl groups, the parts by weight being calculated on the whole of the mixture of the compounds containing hydroxyl groups, and (d) a polyiso yanate blocked at the right level from 5 to 50 parts by weight relative to the total weight of the compounds (a), (b), (c) and (d).
  • the hyperbranched pol ols used according to the present invention belong to the more general family of dendritic molecules, well described in the work. "Denditric Molecules", GR NEWKOME et al., VCH Publ. (1996), more particularly in Chapter 6. These hyperbranched polyols consist of a central monomer or polymer core comprising several identical functional groups, for example hydroxyl groups, that it is reacted with a functional group, such as a carboxyl group, of a branched molecule comprising at least two functional groups different from the first, such as hydroxyl groups. This first extension with branching of the central nucleus is called first generation.
  • hyperbranched polyols have unique properties, such as low polydispersity (with 1 ⁇ Mw / Mn ⁇ 2) and low melt viscosity, even when the molecular weight increases with the number of generations.
  • hyperbranched polyols consist of: i) a central monomer or polymer core which is a compound carrying at least one epoxy group or a reaction product of a polyepoxidized compound still having at least one reactive epoxy group (such as for example l, 2-epoxy-3- allyloxypropane, l-allyloxy-2,3-epoxypropane, l, 2-è ⁇ oxy-3-phenoxypropane, l-glycidyloxy-2-ethylhexane, diglycidyl ether of bisphenol A, isocyanurate triglydicyl, diglycidyl terephthalate, epoxy soybean oil or acid, polyvinyl alcohol epoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, etc.), and ii) at least
  • hyperbranched polyol As an example of this type of hyperbranched polyol, mention may be made of the reaction product of the diglycidyl ether of bisphenol A as component i) with dimethylolpropionic acid as component ii). A hyperbranched polyol belonging to the class of polyesters is thus obtained.
  • hyperbranched polyols of the type of polyesters and of their preparation are given in patent application WO 93 / 17060.
  • These hyperbranched polyesters consist of: i) a central monomer or polymer core chosen from an aliphatic, cycloaliphatic diol or aromatic, a triol, a tetrol (such as ditrimethylolpropane, ditrimethylolethane, pentaerythritol, alkoxylated or not, glycerol, neopentylglycol, dimethylolpropane, 1,3-dioxane-5,5-dimethanol, etc.) sugar such as sorbitol or mannitol, an anhydroene aheptitol, dipentaerythritol, an alpha-alkylglucoside, or else the reaction product of an alkyleneox of or one of its derivatives with one or more hydroxyl groups of the abovementioned alcohol
  • the amorphous polyesters containing hydroxyl groups which can be used in the compositions according to the present invention are polyesters which are well known in the state of the art and commonly used in the formulations of paints and varnishes in powder form for the production of coatings.
  • the amorphous polyesters containing hydroxyl groups used in the thermosetting compositions according to the invention have a hydroxyl number of 10 to 100, and preferably from 20 to 50 mg of KOH / g.
  • ICI viscosity A viscosity in the molten state of 100 to 20,000 mPa.s measured at 200 ° C with a cone / plate viscometer (known as "ICI viscosity"), according to standard ASTM D 4287-88.
  • the acid component of the amorphous polyester used in the thermosetting compositions in accordance with the present invention contains from 70 to 100 mole% of isophthalic and / or terephthalic acid, the 0 to 30 mole% of remaining acids consisting of one or more other aliphatic, and / or cycloaliphatic and / or aromatic polycarboxylic acids having 4 to 15 carbon atoms such as fumaric acid, maleic acid, phthalic acid, acids 1, 2-, 1, 3- or 1, 4- cyclohexanedicarboxylic, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1, 12-dodecanedioic acid, etc., or their corresponding anhydrides.
  • a polycarboxylic acid comprising at least three carboxyl groups or its anhydride, for example trimellitic acid (or anhydride) or pyromellitic acid, allows the preparation of branched
  • the alcoholic constituent of the amorphous polyester used in the thermosetting compositions in accordance with the present invention contains from 60 to 100 mol% of neopentylglycol.
  • the 0 to 40 mole% of the remaining alcohols consist of one or more other aliphatic and / or cycloaliphatic polyols having from 2 to 15 carbon atoms chosen from ethylene glycol, propylene glycol, 1,4-b anediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 2-methyl-1,3-pro ⁇ anediol, 2-butyl-2-ethyl-1,3-propanediol, bisphenol A hydrogenated and neopentylglycol hydroxypivalate.
  • trihydroxylated or tetrahydroxylated polyols such as trimethylolpropane, ditrimethylolpropane, trimethylolethane, pentaerythritol and their mixtures are advantageously used.
  • the semi-crystalline polyesters containing hydroxyl groups according to the invention have the following characteristics:
  • These semi-crystalline polyesters are chosen from two types of compounds, (Cl) or (C2).
  • the acid component of the semi-crystalline polyester (C1) containing hydroxyl groups contains 85 to 100 mole% of terephthalic acid, 1,4-cyclohexanedicarboxylic acid or 1,12-docecanedioic acid and optionally up to 15 moles % of one or more other aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids, such as maleic acid, fumaric acid, isophthalic acid, phthalic acid, 1,2-cyclohexanedicarboxylic acid, l 1,3-cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid.
  • terephthalic acid 1,4-cyclohexanedicarboxylic acid or 1,12-docecanedioic acid
  • These acids can be used in the form of the free acid or their functional derivatives, in particular in the form of the anhydride.
  • a polycarboxylic acid (or its anhydride) comprising at least three carboxyl groups, for example trimellitic acid (or anhydride) or pyromellitic acid, allows the preparation of branched polyesters.
  • these di- or polycarboxylic acids can be used alone or as a mixture, but preferably they are used alone.
  • the alcohol component of the semi-crystalline polyester (C1) containing hydroxyl groups contains 85 to 100 mole% of a saturated aliphatic diol with straight chain.
  • diols which can be used are ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, etc.
  • semi-crystalline polyester (Cl) can also contain up to 15 mol% of one or more other aliphatic or cycloaliphatic diols or polyols, such as, for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol or bisphenol A hydrogen.
  • aliphatic or cycloaliphatic diols or polyols such as, for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol or bisphenol A hydrogen.
  • trihydroxylated or tetrahydroxylated polyols such as trimethylolpropane, ditrimethylolpropane or pentaerythritol and their mixtures, are advantageously used.
  • the acid component of the semi-crystalline polyester (C2) containing hydroxyl groups contains 85 to 100 mole% of a saturated aliphatic straight chain dicarboxylic acid.
  • the acids which can be used are succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, acid 1, 12 -dodecanedioic, etc. These acids can be used in the form of free acids or their functional derivatives, in particular in the form of anhydrides. In addition, these acids can be used alone or as a mixture, but preferably they are used alone.
  • the acid component of the semi-crystalline polyester (C2) containing hydroxyl groups may also contain up to 15 mol% of one or more other aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids having from 4 to 8 carbon atoms, such as as maleic acid, fumaric acid, terephthalic acid, phthalic acid, isophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4 acid - cyclohexanedicarboxylic.
  • polycarboxylic acid or its anhydride
  • trimellitic acid or anhydride
  • pyromellitic acid allows the preparation of branched polyesters.
  • these di- or polycarboxylic acids can be used alone or as a mixture, but preferably they are used alone.
  • the alcohol component of the semi-crystalline polyester (C2) containing hydroxyl groups contains 85 to 100 mol% of 1,4-cyclohexanediol or 1,4-cyclohexanedimethanol or ethylene glycol.
  • the alcoholic constituent of this semi-crystalline polyester (C2) can also contain up to 15 mol% of one or more other aliphatic or cycloaliphatic di- or polyols having from 2 to 15 carbon atoms such as propylene glycol, 1 , 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.
  • trihydroxylated or tetrahydroxylated polyols such as trimethylolpropane, ditrimethylolpropane, trimethylolethane or pentaerythritol, etc., are advantageously used.
  • Semi-crystalline or amorphous polyesters containing hydroxyl groups are prepared according to conventional methods of synthesis of polyesters by t: sterification in one or more stages. If one proceeds in one stage to obtain the polyesters, a stoichiometric excess of one or more diols or polyols is reacted together with one or more suitable di- or polycarboxylic acids.
  • a polyester containing carboxyl groups is first prepared from a stoichiometric excess of one or more di- or polycarboxylic acids and one or more diols or polyols and the polyester containing carboxyl groups thus obtained is then esterified with one or more other suitable diols or polyols to obtain a semi-crystalline or amorphous polyester containing hydroxyl groups.
  • a conventional reactor For the preparation of semi-crystalline or amorphous polyesters containing hydroxyl groups, a conventional reactor is generally used provided with a stirrer, an inert gas (nitrogen) inlet, a distillation column connected to a cooled condenser. with water and a thermometer connected to a thermoregulator.
  • a stirrer for the preparation of semi-crystalline or amorphous polyesters containing hydroxyl groups, a conventional reactor is generally used provided with a stirrer, an inert gas (nitrogen) inlet, a distillation column connected to a cooled condenser. with water and a thermometer connected to a thermoregulator.
  • esterification conditions used for the preparation of these polyesters are conventional, namely that it is possible to use a conventional esterification catalyst derived from tin, such as dibutyltin oxide, dibutyltin dilaurate, trioctoate of n-butyltin or titanium derivative, such as tetrabutyl titanate, in a proportion of 0 to 1% by weight of the reagents, and optionally add antioxidants such as the phenolic compounds IRGANOX 1010 (CIBA-GEIGY) or IONOL CP
  • SHELL SHELL
  • stabilizers of phosphonite or phosphite type such as tributyl phosphite or triphenyl phosphite, in an amount of 0 to 1% by weight of the reactants.
  • the polyesterification is generally carried out at a temperature which is gradually increased from 130 ° C. to approximately 180 to 250 ° C., first under normal pressure, then under reduced pressure while maintaining these conditions until a polyester having the desired hydroxyl and / or acid number and viscosity.
  • the degree of esterification is followed by determining the amount of water formed during the reaction and the properties of the polyester obtained, for example, the hydroxyl number, the acid number, the molecular weight and / or viscosity.
  • catalysts can be added thereto to accelerate the crosslinking reaction, at a rate of 0 to 1.5% by weight relative to the polyesters.
  • organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin oxide, tin octanoate, l, 3-diacetoxy-l, l, 3,3-tetrabutyldistanoxane and similar compounds.
  • Hyperbranched polyols, amorphous polyesters containing hydroxyl groups and semi-crystalline polyesters containing hydroxyl groups described above are intended to serve mainly as binders, together with crosslinking agents, in the preparation of thermosetting powder compositions usable in particular as varnishes and paints suitable for application according to the deposition technique by means of an electrostatic spray gun or triboelectric or according to the technique of deposition in a fluidized bed.
  • the present invention also relates to the use of the thermosetting powder compositions in accordance with the invention for the preparation of powder varnishes and paints, as well as to the powder varnishes and paints obtained using these compositions.
  • thermosetting powder composition in accordance with the invention by spraying with an electrostatic spray gun or triboelectrically or by deposition in a fluidized bed followed by a baking of the coating thus obtained at a temperature of 150 to 220 ° C for a period from about 5 to 35 minutes.
  • the crosslinking agent used for the preparation of the thermosetting powder compositions in accordance with the invention is chosen from compounds containing functional groups capable of reacting with the hydroxyl groups of the hyperbranched polyol and of the polyesters. Among these compounds, blocked polyisocyanates are used as crosslinking agents.
  • the blocked polyisocyanates used as crosslinking agents according to the present invention are compounds well known in the art. They are commercially available or they can be prepared according to well described methods. When the powders are cooked to prepare coatings according to the invention, these polyisocyanates are released and the isocyanate groups react with the hydroxyl groups present on the hyperbranched polyol, on the amorphous polyester and on the semi-crystalline polyester if the powder contains them , which causes cross-linking of the polymer chains.
  • blocked polyisocyanates examples include those based on isophorone diisocyanate blocked with epsilon-caprolactam, commercially available under the brands HULS B1530, RUCO NI-2 and CARGILL 2400. Mention may also be made of 2 , 4-toluene diisocyanate blocked by epsilon-caprolactam, commercially available under the brand CARGILL 2450, as well as hexamethylene diisocyanate blocked with phenol.
  • the polyisocyanate preferably used as a crosslinking agent belongs to the group of isophorone diisocyanates blocked with epsilon-caprolactam.
  • Another class of blocked polyisocyanates useful as crosslinkers in thermosetting powder compositions consists of the adducts of dimer l, 3-diazetidine-2,4-dione derivative of isophorone diisocyanate with a diol, in which the molar ratio between the isocyanate and hydroxyl groups is from 1 / 0.5 to 1 / 0.9, and the molar ratio between the diazetidinedione and the diol is from 2/1 to 6/5; in these adducts, the content of free isocyanate groups is not higher than 8% by weight, their molecular weight ranges from 500 to 4,000 and their melting temperature ranges from 70 to 130 ° C.
  • Such adducts can be prepared according to the method described in US Pat. No. 4,413,079 by reacting the diazetidinedione dimer of isophorone diisocyanate, preferably free of trimer, with diols using quantities of reagents such that a molar ratio between the isocyanate and hydroxyl groups ranging from 1 / 0.5 to 1 / 0.9, preferably from 1 / 0.6 to 1 / 0.8, is obtained; such an adduct has a molecular weight of 1,450 to 2,800, preferably, and a melting temperature of 85 to 120 ° C; the preferred diol is 1,4-butanediol.
  • Such an adduct is commercially available under the brand HULS BF 1540, or under the brand CRELAN LS2147 from BAYER.
  • the amount of blocked polyisocyanate used as crosslinking agent in the compositions according to the invention varies according to different factors, such as the characteristics of the particular hyperbranched polyol used, as well as those of the amorphous and semi-crystalline polyesters; other factors varying the amount of crosslinker to be used are the nature and characteristics of the latter, the degree of pigment load, the desired properties of the coatings to be prepared using the compositions, etc.
  • the amount of crosslinking agent to be used to prepare coatings having a good combination of properties is of the order of 5 to 50% by weight, and preferably 25 to 40% by weight, calculated on the total weight hyperbranched polyol, amorphous polyester containing hydroxyl groups, semi-crystalline polyester containing hydroxyl groups optionally present, and crosslinking agent.
  • a hyperbranched polyol from the compounds containing hydroxyl groups, 5 to 50 parts by weight of a hyperbranched polyol are chosen, and preferably from 10 to 30 parts by weight, from 2.5 to 95 parts by weight of an amorphous polyester containing hydroxyl groups, and preferably from 50 to 90 parts by weight, and from 0 to 90 parts by weight of a semi-crystalline polyester containing hydroxyl groups, and preferably from 0 to 40 parts by weight, these parts by weight being calculated on the total weight of the compounds containing hydroxyl groups.
  • thermosetting powder compositions makes it possible to obtain coatings whose reproducibility can be very easily controlled very reproducibly depending on the amount of the hyperbranched polyol and its generation number, as will be seen later in the examples.
  • Other coating properties such as flexibility, surface appearance, resistance to chemicals and weathering, are excellent.
  • the semi-crystalline polyester is added to the compositions, an improvement in the mechanical properties of the coatings is obtained.
  • all these results are obtained in a single extrusion of the powder.
  • thermosetting powder compositions according to the invention can also contain various auxiliary substances conventionally used in the manufacture of powder paints and varnishes.
  • thermosetting compositions in accordance with the invention are inter alia ultraviolet ray absorbing compounds such as Tinuvin 900 (from CIBA-GEIGY Corp.), light stabilizers based on hindered amines (by example Tinuvin 144 from CIBA-GEIGY Corp.).
  • the compositions in accordance with the invention can contain up to 10% by weight thereof relative to the weight of the polyesters.
  • a variety of pigments and mineral fillers can also be added to the thermosetting compositions according to the invention.
  • pigments and fillers examples include metal oxides such as titanium dioxide, iron oxide, zinc oxide, etc., metal hydroxides, metal powders, sulfides, sulfates, carbonates, silicates such as for example aluminum silicate, carbon black, talc, kaolins, barytes, iron blues, lead blues, organic reds, organic browns, etc. Mention will also be made, as auxiliary substances, of fluidity regulating agents such as Resiflo PV5 (from WORLEE) or Modaflow (from MONSANTO), or Acronal 4F (from BASF), and degassing agents such as benzoin. These auxiliary substances are used in usual quantities, it being understood that if the thermosetting compositions according to the invention are used as varnish, the addition of auxiliary substances having opacifying properties will be omitted.
  • metal oxides such as titanium dioxide, iron oxide, zinc oxide, etc.
  • metal hydroxides metal powders, sulfides, sulfates, carbonates, silicates
  • the hyperbranched polyol, the amorphous polyester, the semi-crystalline polyester, the crosslinking agent and the various auxiliary substances conventionally used for the manufacture of powder paints and varnishes are dry mixed. example in a drum mixer. This mixture is then homogenized to a temperature in the range of 80 to 150 ° C in an extruder, for example a Buss-Ko-Kneder single screw extruder or a twin screw extruder of the Prism or APV type Then, the extrudate is allowed to cool, it is grinds, optionally cryogenically using liquid nitrogen, and is sieved to obtain a powder whose particle size is between 10 and 150 micrometers.
  • an extruder for example a Buss-Ko-Kneder single screw extruder or a twin screw extruder of the Prism or APV type
  • the extrudate is allowed to cool, it is grinds, optionally cryogenically using liquid nitrogen, and is sieved to obtain a powder whose particle size is between 10 and
  • powder paints and varnishes thus obtained are perfectly suitable for application to the article to be coated by traditional techniques, that is to say by the well-known technique of deposition in a fluidized bed or by application with an electrostatic or triboelectric spray gun. .
  • additives that are known to add charge in triboelectric systems are optionally added.
  • the coatings deposited are cured by baking in an oven at a temperature of 160 to 220 ° C. for a period of approximately 5 to 35 minutes in order to obtain complete crosslinking of the coating.
  • the mixture is heated in a nitrogen atmosphere and with stirring to a temperature of about 230 ° C; the water formed begins to distill around 180 ° C.
  • a portion of tributylphosphite is added, and a vacuum of 50 mm Hg is gradually established.
  • the amorphous polyester containing hydroxyl groups thus obtained has the following characteristics: hydroxyl number 47 mg KOH / g acid number of 3 mg KOH / g
  • polyester is cooled to 180 ° C. and 2.5 parts of phosphite of tri- (2,4-di-tert.butylphenyl) and 2.5 are added thereto. parts of octadecyl-3- (3,5-di-tert.butyl-4-hydroxyphenyl) propionate. After 1 hour of stirring, the polyester is discharged from the reactor.
  • Tm Melting temperature
  • the semi-crystalline polyester containing hydroxyl groups is cooled to 160 ° C. and 10 parts of Tinuvin 144 and 20 parts of Tinuvin 900 are added thereto. After one hour of stirring, the polyester contained in the flask is recovered.
  • the hyperbranched polyols of these examples consist of a central nucleus which is the ethoxylated pentaerythritol. Dimethylolpropionic acid is grafted onto this core, to make a hyperbranched polyol of the second, third and fourth generation, which constitutes Examples 7, 8 and 9 respectively, as described in patent application WO 93/17060 to examples 27, 28 and 29 respectively.
  • These hyperbranched polyols are commercially available under the brand name BOLTORN from the company PERSTORP.
  • Table I shows the characteristics of the hyperbranched polyol of each of these three examples.
  • the 1st line gives the number of the example as well as the number of generations; the second line the hydroxyl number, in mg of KOH / g;
  • Viscosity HERE (mPa.s). 1,400 8,400 34,000 at 125 ° C!
  • a series of powders which can be used for the manufacture of coatings are prepared, according to the following two different formulations, one of white color (formulation A) and the other of dark brown color (formulation B):
  • Titanium dioxide (1) 300.0 parts
  • Fluidity control agent (2) 10.0 parts
  • Fluidity control agent (2) 10.0 parts
  • the binder of these formulations contains either a mixture of hyperbranched polyol and amorphous polyester containing hydroxyl groups (compositions 17 to 20), or, a mixture of hyperbranched polyol, amorphous polyester containing hydroxyl groups and semi-crystalline polyester containing hydroxyl groups (compositions 10 to 16 and 21 to 24), as indicated in Table II.
  • Dibutyltin dilaurate was also added to these formulations as a crosslinking catalyst, in an amount of 0.6% by weight relative to the semi-crystalline and amorphous polyesters.
  • the hyperbranched polyol, the amorphous polyester and the semi-crystalline polyester can be used as a mixture or as separate resins.
  • the constituents can be mixed, either in the molten state in a conventional flask until the mixture is homogeneous, or by using an extruder, for example of the Betol BTS type.
  • the powders are prepared by dry mixing and homogenizing the binder, a blocked polyisocyanate as crosslinking agent and the various auxiliary substances conventionally used for the manufacture of powder paints and varnishes.
  • the mixture is homogenized and extruded at a temperature of 85 ° C. in a twin screw extruder, of the Prism 16 mm L / D 15/1 type (from the company PRISM).
  • the extrudate is cooled and ground in a grinder such as the Retsch ZM 100 having meshes of 0.5 mm (from the company RETSCH).
  • the powder is sieved to obtain a particle size between 10 and 100 micrometers.
  • thermosetting powder compositions thus prepared are listed in Table II.
  • the powders, formulated as described above, are applied with the electrostatic spray gun GEMA-Volstatic PCG 1, at a voltage of 60 kV, on cold-rolled steel panels, untreated, in a film thickness of 50 to 70 micrometers.
  • the coatings deposited are then subjected to a baking in an oven ventilated with air at a temperature of 200 ° C, for a period of 15 minutes.
  • the hardened coatings thus obtained are subjected to conventional tests. The results obtained are reported in Table II.
  • the 1st column gives the number of the example of the composition prepared
  • the 2nd column the type of formulation A or B used
  • the 3rd column the number of the example of preparation of the amorphous polyester containing hydroxyl groups used in the composition prepared, as well as the quantity used of this polyester, in parts by weight
  • the 4th column the number of the example of preparation of the semi-crystalline polyester containing hydroxyl groups used in the composition prepared, as well as the quantity used of this polyester, in parts by weight
  • the 5th column the number of the example describing the hyperbranched polyol used in the composition prepared, as well as the quantity of this polyol used, in parts by weight
  • the 6th column the nature and quantity of the blocked polyisocyanate used as crosslinking agent, in parts by weight; in this column, the abbreviations have the following meaning: BF 1540: the composition of this polyisocyanate is given above in this specification.
  • the coatings obtained with the various powder compositions according to Examples 10 to 24 all have a smooth and regular surface appearance, without any defect such as pinholes or craters, and a matt or semi-matt appearance.
  • the present invention provides a very versatile and flexible means for producing coatings of a desired degree of mattness, by playing on parameters such as the quantity and the number of generations of the hyperbranched polyol, as well as, to a lesser extent , on the nature of the crosslinking agent and of the polyesters.
  • the weather resistance of paint coatings obtained with the mixture of hyperbranched polyol, amorphous polyester and semi-crystalline polyester of the composition of Example 24, in accordance with the invention is compared with that of 'A coating obtained with a composition not in accordance with the invention.
  • the pigmented powders formulated are applied with an electrostatic spray gun to chromated aluminum panels under the same conditions as in Example 24.
  • the coatings were subjected to an accelerated aging test in order to assess their resistance to weathering (Q-UV test).
  • the gloss values measured at an angle of 60 ° are measured according to standard ASTM D523, every 200 hours.
  • the comparison composition formulated according to type B, contains an amorphous polyester containing hydroxyl groups, consisting of terephthalic acid and neopentylglycol, of hydroxyl index of 30 mg KOH / g, as well as the blocked polyisocyanate B 1530 marketed by the firm HULS (described in examples 10 to 24), in a ratio 88 / 12.
  • a reduction of 50% in the initial value of the gloss is observed, which is 92% after only 2,400 hours.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Paints Or Removers (AREA)
  • Polyesters Or Polycarbonates (AREA)
EP99969427A 1998-09-22 1999-09-10 Hitzehärtbare pulverzusammensetzungen zum herstellen von beschichtungen mit geringem glanz Withdrawn EP1165714A1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
BE9800679 1998-09-22
BE9800679A BE1012176A3 (fr) 1998-09-22 1998-09-22 Compositions thermodurcissables en poudre pour la preparation de revetements de faible brillant.
PCT/EP1999/006729 WO2000017279A1 (fr) 1998-09-22 1999-09-10 Compositions thermodurcissables en poudre pour la preparation de revetements de faible brillant

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CN101481578B (zh) * 2009-02-03 2011-01-19 广州慧谷化学有限公司 具有耐深冲性能且高温不黄变的电容器涂料及其制备方法

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GB2493936A (en) 2011-08-23 2013-02-27 Nipsea Technologies Pte Ltd A high solids content polymer composition

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JPS63154771A (ja) * 1986-12-17 1988-06-28 Nippon Ester Co Ltd 艶消し粉体塗料用樹脂組成物
ATE127822T1 (de) * 1990-07-20 1995-09-15 Eastman Chem Co Pulver-beschichtungsmasse.
JPH0753630A (ja) * 1993-06-30 1995-02-28 Shell Internatl Res Maatschappij Bv 末端に水酸基を有する液状スターポリマー
US5554692A (en) * 1994-01-06 1996-09-10 Ferro Corporation Blocked isocyanate crosslinkers based on pentaerythritol for use in thermosetting coatings
SE503622C2 (sv) * 1994-12-21 1996-07-22 Perstorp Ab Ett härdplastmaterial tillverkat av en härdplastkomposition innefattande en kedjeterminerad dendritisk eller hyperförgrenad makromolexyl av polyestertyp
DE19611368C1 (de) * 1996-03-22 1997-11-20 Bayer Ag Mischungen, enthaltend A) Reaktionsprodukte aus Isocyanaten mit NCO-reaktiven Silanen und B) Carbosilan-Dendrimere, ein Verfahren zur Herstellung von Pulverlacken aus den Mischungen und deren Verwendung

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CN101481578B (zh) * 2009-02-03 2011-01-19 广州慧谷化学有限公司 具有耐深冲性能且高温不黄变的电容器涂料及其制备方法

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