WO1998045348A1 - Systemes de revetements a faible teneur en voc a base de polymeres acryliques et d'isocyanate bloque et leur procede de preparation - Google Patents

Systemes de revetements a faible teneur en voc a base de polymeres acryliques et d'isocyanate bloque et leur procede de preparation Download PDF

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Publication number
WO1998045348A1
WO1998045348A1 PCT/EP1998/002142 EP9802142W WO9845348A1 WO 1998045348 A1 WO1998045348 A1 WO 1998045348A1 EP 9802142 W EP9802142 W EP 9802142W WO 9845348 A1 WO9845348 A1 WO 9845348A1
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Prior art keywords
coating system
isocyanate
acrylic
blocked isocyanate
polymerization
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PCT/EP1998/002142
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English (en)
Inventor
Scott E. Smyth
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Cook Composites And Polymers Company
Cray Valley S.A.
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Publication of WO1998045348A1 publication Critical patent/WO1998045348A1/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
    • C08G18/40—High-molecular-weight compounds
    • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
    • C08G18/6216—Polymers of alpha-beta ethylenically unsaturated carboxylic acids or of derivatives thereof
    • 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
    • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
    • C08G18/6216—Polymers of alpha-beta ethylenically unsaturated carboxylic acids or of derivatives thereof
    • C08G18/622—Polymers of esters of alpha-beta ethylenically unsaturated carboxylic acids
    • C08G18/6225—Polymers of esters of acrylic or methacrylic acid
    • C08G18/6229—Polymers of hydroxy groups containing esters of acrylic or methacrylic acid with aliphatic polyalcohols
    • 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
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
    • C08G18/751—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring
    • C08G18/752—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group
    • C08G18/753—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group
    • C08G18/755—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
    • 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
    • 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
    • C08G18/8064—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with monohydroxy compounds

Definitions

  • This invention relates to protective coating systems.
  • the invention relates to coating systems that exhibit low volatile organic compound (“VOC”) and/or hazardous air polluting system (“HAPS") -free emissions while in another aspect, the invention relates to the preparation of such coating systems by dispersing the reaction product of a blocked isocyanate and one or more acrylic polymers in water or water containing a resin.
  • the reaction product of the blocked isocyanate and acrylic polymer is mixed with a reactive or non reactive solvent to form a high solids coating system.
  • low VOC and/or HAPS-free coating systems comprise (i) at least one blocked isocyanate, (ii) at least one acrylic polymer, (iii) water, (iv) optionally and preferably, a urethane catalyst.
  • the systems comprise (i) at least one blocked isocyanate, (ii) at least one acrylic polymer, (iii) a solvent, (iv) at least one resin, and (v) optionally and preferably, a urethane catalyst.
  • the coating systems of this invention are prepared by a process comprising the steps of (i) reacting by contacting an isocyanate and a blocking compound, (ii) removing excess blocking compound, if any, from the resulting blocked isocyanate, (iii) adding one or more hydroxy or epoxy functional acrylic monomers to the blocked isocyanate, and then polymerizing these monomers to form an acrylic polymer, (iv) mixing the resulting reaction product with either (a) water or water and a resin, or (b) a solvent or a solvent and a resin, and (v) optionally and preferably adding a urethane catalyst to the mixture of (iv) .
  • low VOC means vaporous emissions of volatile organic compounds as measured by ASTM 24 of less than about 419,4 kg/m (3.5 pounds per gallon, lb/gal), preferably less than about 239,7 kg/m (2 lb/gal) and more preferably less than about 59,9 kg/m (0.5 lb/gal).
  • HAPS-free means vaporous emissions of hazardous air
  • the isocyanate compound must have at least one functional group (NCO) preferably at least two functional groups (polyfunctional and typically referred to as a polyisocyanate) , and it must be capable of reacting with the blocking compound.
  • suitable isocyanate compounds include tetramethylxylene isocyanate, 2,4- and 2,6-toluene diisocyanate (TDI) , 4,4 ' -diphenylmethylene diisocyanate (MDI) , polymethylene polyphenyl isocyanate (PMPPI) , dianisidine diisocyanate, metaphenylene diisocyanate, isophorone diisocyanate (IPDI) , hexamethylene diisocyanate (HDI) , urethanes, biurets, isocyanurates and mixtures of any two or more of these compounds.
  • the preferred isocyanates are liquefied IPDI, HDI or biurets of HDI because of their low
  • these blocking compounds are monohydroxyl compounds and representative of these compounds are those illustrated by the formula :
  • R' is hydrocarbyl such as alkyl, cycloalkyl, aryl, aralkyl, alkaryl, etc ., preferably containing up to 18, and more preferably containing four or less, carbon atoms ;
  • R" is an alkylene radical, preferably of two to four carbon atoms ; and
  • a is an integer of 0 to 18 , preferably of 0 to 2.
  • Illustrative monohydroxyl blocking compounds include the alkanols, e.g.
  • the monoalkyl ethers of glycols and polyglycols e.g., 2-ethoxyethanol, 2- propoxyethanol , 2-butoxyethanol, the mono
  • blocking compounds include oximes, e.g. methyl ethyl ketoxime, acetone oxi e, cyclohexyl oxi e, and the like ; lactams, e.g. ?- caprolactam, etc. ; alkanolamines, e.g. diethylethanolamine, diethanolmethylamine, etc. ; phenols and malonic diesters.
  • the choice of blocking compound is usually determined by the desired properties of the coating or film and the curing conditions (e.g. baking temperature) employed.
  • the isocyanate groups are blocked by reacting by contacting, preferably in the absence of a catalyst, the isocyanate compound with a stoichio etric amount, typically with a slight excess of a stoichiometric amount, e.g. an excess of about 5 to about 30, preferably about 8 to 15, mole percent of blocking compound at a temperature and at other reaction conditions under which the blocking reaction can proceed to completion (all of which are well known in the art) .
  • the minimum temperature for the blocking reaction is typical at least about 35, preferably at least about 60 and more preferably at least about 80°C, while the maximum temperature typically is not in excess of about 150, preferably not in excess of about 120 and more preferably not in excess of 110 °C.
  • the pressure at which the blocking reaction is conducted can vary to convenience, but it is preferably at or slightly in excess of atmospheric pressure.
  • the reaction is conducted with sufficient agitation to insure complete mixing of the reactants and a relatively uniform temperature throughout the reaction mass, and the exotherm from the reaction is controlled by any conventional means, e.g. metered addition of the isocyanate to the blocking agent, the use of a cooling apparatus, etc.
  • the blocked isocyanate is then used as a solvent, i.e. a reaction media, for the preparation of the acrylic polymer.
  • solvents such as the glycol ethers, acetates, glycol ether acetates, ketones, and aromatic and aliphatic compounds were used, but these solvents contributed to the VOC's and/or HAPS's of the coating systems.
  • Sufficient blocked isocyanate is used such that an equivalents ratio of isocyanate functionalities on the blocked isocyanate to the hydroxy or epoxy groups on the finished acrylic polymer product is between about 1:1 to about 4:1, preferably between about 1:1 to about 3:1, and more preferably between about 1:1 and about 1:2.
  • the monomers used to prepare the acrylic polymer include a wide class of hydroxy or epoxy functional ethylenically unsaturated monomers, and particularly useful members of this class are the acrylic polymers which are well established for the production of coatings in the automobile industry, e.g. hydroxy or epoxy functional polymers or copolymers of one or more alkyl esters of acrylic acid or methacrylic acid, optionally together with other ethylenically unsaturated monomers. These polymers may be of either the thermoplastic type or the thermosetting, crosslinking type.
  • Suitable hydroxy or epoxy functional polymers are obtained from monomers including acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2- hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, allyl alcohol, allyl alcohol propoxylate, glycidyl acrylate and glycidyl methacrylate.
  • the acrylic polymerization is promoted with the use of known vinyl polymerization catalysts, and these catalysts include peroxides, persulfides, perborates, percarbonates, and azo compounds or any other suitable catalyst capable of catalyzing the vinyl polymerization of the acrylic monomer, e.g. methyl methacrylate, and/or the ethylenically unsaturated monomer, e.g. styrene.
  • these catalysts include peroxides, persulfides, perborates, percarbonates, and azo compounds or any other suitable catalyst capable of catalyzing the vinyl polymerization of the acrylic monomer, e.g. methyl methacrylate, and/or the ethylenically unsaturated monomer, e.g. styrene.
  • catalysts are benzoyl peroxide (BPO) , tertiarybutyl-peroxybenzoate, 2,2' -azo-bis-isobutyronitrile, lauryl peroxide, di-tertiarybutylperoxide, diisopropyl peroxide carbonate, tertiarybutylperoxy-2-ethylhexanoate, and the like.
  • BPO benzoyl peroxide
  • tertiarybutyl-peroxybenzoate 2,2' -azo-bis-isobutyronitrile
  • lauryl peroxide di-tertiarybutylperoxide
  • diisopropyl peroxide carbonate tertiarybutylperoxy-2-ethylhexanoate
  • pphr parts per hundred parts of monomers
  • Promoters for the vinyl polymerization can also be used in combination with vinyl polymerization peroxide catalysts to control the rate of free radical initiation.
  • Suitable promoters for use with peroxide catalysts, e.g. BPO include N,N-diethylaniline, N,N-dimethyl paratoluidine, other tertiary aromatic amines, and the like.
  • the acrylic polymerization is conducted using known techniques and conditions, e.g. it is typically conducted at a temperature of at least about 50, preferably at least about 120 and more preferably at least about 150 °C and preferably at a temperature not in excess of about 200, preferably not in excess of about 175 and more preferably not in excess of 165 °C.
  • the pressure at which the polymerization is conducted can vary to convenience, but it is preferably at or slightly in excess of atmospheric pressure.
  • the polymerization can be performed on a batch, semi-continuous or continuous basis and depending upon the nature of the monomers, in the presence or absence of an inert atmosphere, e.g. a nitrogen blanket.
  • an inert atmosphere e.g. a nitrogen blanket.
  • the use of an inert atmosphere is preferred to promote better color since upon exposure to oxygen aromatic isocyanates tend to yellow and amines tend to darken.
  • the blocked isocyanate is typically and preferably stripped of any unreacted blocking agent by any conventional means, e.g. heat distillation, vacuum stripping, etc.
  • the resulting product of the acrylic polymerization comprises acrylic polymer and blocked isocyanate which is then mixed, e.g. dissolved, dispersed, emulsified, etc., in water, optionally containing a resin.
  • the acrylic polymerization product is mixed with water and a resin.
  • the acrylic polymerization product, water and resin can be mixed in any order, but preferably the water and resin are first mixed and then the water resin mix is added to the acrylic polymerization product.
  • the amount of water used to make the mixture can vary widely, but usually the minimum amount of water is at least about 10, preferably at least about 40 and more preferably at least about 60, percent by weight based on the total weight of the mixed composition, and usually the amount of water is not in excess of about 90 percent, preferably not in excess of about 80 and more preferably not in excess of about 70, weight percent. The less water that is present, the better for building film or coating thickness, and thus the less need for recoating.
  • the resin is typically first neutralized with a neutralizing agent to the extent that the resin contains one or more functionalities which would otherwise ionize upon mixing with water. If the functionality is acid in nature, then an appropriate amount of a suitable base, e.g. an amine, is added to and well mixed with the polymer before mixing the polymer with water.
  • a neutralizing agent e.g. an amine
  • a neutralizing amount e.g. stoechiometric or a slight stoichiometric excess
  • a suitable acid e.g. lactic acid
  • agitation is continued until an emulsion, usually milky in appearance, is formed.
  • high shear means sufficient shear to form a stable emulsion from the materials at hand. The actual shear necessary to create an emulsion will be dependent upon such variables as the nature and concentrations of the various components, the blade and container configurations, and similar such considerations familiar to those skilled in the art.
  • the acrylic polymerization product is mixed in any suitable solvent to produce a high (e.g. 838,8 kg/m or more or 7 or more lb/gal of resin) solids coating system.
  • suitable solvents are those that will reduce the viscosity of the acrylic polymerization product to that needed for a particular application, e.g. spraying, dipping, electrodeposition, etc.
  • the solvent can be either reactive, e.g. it will react with either the acrylic polymer or the deblocked isocyanate during the cure, or non-reactive, i.e. it will not react with either the acrylic polymer or the deblocked isocyanate during the cure.
  • Representative solvents include methyl ethyl ketone, methyl amyl ketone, butyl acetate, tripropylene glycol, diethylene glycol, glycerine, hydroxy or epoxy functional monomers such as hydroxypropyl acrylate, and the like.
  • the amount of solvent used to make the mixture can vary widely, but usually the minimum amount of solvent is at least about 10, preferably at least about 30 and more preferably at least about 50, percent by weight based on the total weight of the mixed composition, and usually the amount of solvent is not in excess of about 90 percent, preferably not in excess of about 70 and more preferably not in excess of about 65, weight percent. The less solvent that is present, the better for building film or coating thickness, and thus the less need for recoating.
  • the optional resin (s) used in practice of this invention include any of those well known in the coating industry, e.g. the polyesters, polyethers, alkyds, etc., such as those described in "Surface Coatings" by S. Paul (Wiley- Interscience, New York, 1985) , “Polyesters and their Applications”, Bjorksten Research Laboratories (Reinhold, New York, 1956), “Polyethers” by N.G. Gaylord (ed.) (Part 1, Wiley-Interscience, New York, 1963), and "Alkyd Resins” by CR. Martens (Reinhold, New York, 1961) .
  • these resins readily react with one or both of the acrylic polymer and deblocked isocyanate during the cure of the coating system.
  • the amount, if any, and nature of the resin used in the coating systems of this invention can vary to convenience, and these considerations are usually determined by the desired properties of the coating.
  • the isocyanate is deblocked and the blocking agent is either or both emitted as a gas or remains in the coating.
  • the released blocking agent can serve various purposes. In those instances in which flexibility is a desirable property of the coating, some blocking agents can act as a plasticizer.
  • Other blocking agents e.g. glycol ethers, have a leveling effect, i.e. they promote the smooth flow of the coating during cure.
  • the cure process is promoted by catalysts that promote the formation of urethane bonds and, preferably, also promote the deblocking of the isocyanate.
  • Representative catalysts include (a) tertiary amines such as N,N-dimethylcyclohexylamine, (b) tertiary phosphines such as trialkylphosphines, (c) strong bases such as alkali and alkaline earth metal hydroxides and phenoxides, (d) acidic metal salts of strong acids such as ferric chloride, (e) organo-tin compounds such as dibutyl tin dilaurate, and (f) cyclic amines such as 1, 5-diazabicyclo(5.5.0)undec-5-ene.
  • tertiary amines such as N,N-dimethylcyclohexylamine
  • tertiary phosphines such as trialkylphosphines
  • strong bases such as alkali and alkaline earth metal hydroxides and phenoxides
  • acidic metal salts of strong acids such as ferric chloride
  • organo-tin compounds
  • the mixture of acrylic polymerization product and (i) water, or (ii) water and a resin, or (iii) solvent, or (iv) solvent and a resin can contain one or more a,b-ethylenically unsaturated monomers which can crosslink with the deblocked isocyanate and/or acrylic polymer or self-polymerize through thermally or ultraviolet light induced free radical polymerization during cure.
  • a,b-ethylenically unsaturated monomers which can crosslink with the deblocked isocyanate and/or acrylic polymer or self-polymerize through thermally or ultraviolet light induced free radical polymerization during cure.
  • the presence of such monomers provide a high solids, dual-curing coating system.
  • the concentration of these monomers is usually less than about 30, preferably less than about 10 and more preferably less than about 5, weight percent based upon the total weight of the mixture, and the vinyl crosslinking is promoted with one or more free radical initiators, e.g. a catalytic amount of a peroxide.
  • free radical initiators e.g. a catalytic amount of a peroxide.
  • Illustrative monomers include the mono-, di- and trifunctional acrylic and methacrylic esters, glycidyl acrylates and methacrylates, N-vinyl-2-pyrrolidone, N-methacrylamide, the hydroxyalkyl esters of acrylic and methacrylic acid, and aromatic vinyl and divinyl compounds, e.g. styrene.
  • unsaturated monomers with relatively low volatility under process conditions such as the polyfunctional acrylic and methacrylic esters
  • unsaturated monomers with relatively low volatility under process conditions such as the polyfunctional acrylic and methacrylic esters
  • free radical initiators include benzoyl peroxide, tertiarybutylperoxybenzoate, 2, 2 ' -azo-bis- isobutyronitrile, lauryl peroxide, di-tertiarybutylperoxide, diisopropyl peroxide carbonate, tertiarybutylperoxide-2- ethylhexanoate, and the like.
  • the coating systems of this invention can be applied to a wide array of substrates, e.g. metal, plastic, ceramic, wood, etc. , in any conventional manner, e.g. electrodeposition, spraying, drawing, dipping, powder coatings, and the like. Cure can be effected under ambient conditions or promoted with heat, light, etc.
  • Isophorone diisocyanate 500 g is placed in an addition funnel which is attached to a one liter resin kettle charged with anhydrous ethanol (285 g) .
  • the temperature of the resin kettle is gradually increased to 80°C at which time the addition of the IPDI to the ethanol begins.
  • the IPDI is added to the ethanol at a constant rate, and the addition is completed at the end of five hours. At that time, the temperature of the resin kettle is 120 °C and the reaction product is clear and of low viscosity.
  • the percent of free isocyanate is usually less than 0.5 weight percent (based on the total weight of the reaction product) .
  • the blocked isocyanate is then tested for the stability or propensity of the ethanol to deblock from the isocyanate, i.e. the propensity of the urethane linkage formed by the reaction of the isocyanate and ethanol to break.
  • reaction product Upon cooling to room temperature, the reaction product is measured to comprise 89 weight percent of non- volatile material with a viscosity of 50 Pa.s (500 poise) and a water-clear color.
  • the free isocyanate is measured at less than one weight percent.
  • Example 1 is charged to one liter reactor equipped with reflux, nitrogen sparger, two addition funnels, a mechanical agitator and a temperature controller. The temperature of the reactor is raised over 75 minutes from ambient to 150 " C to strip excess ethanol by distillation from the blocked isocyanate. Sixty minutes after reaching 150 °C, initiator (dicumyl peroxide (2.3 g) dissolved in styrene (20 g) ) is added to the reactor at a rate of about 1 drop every 10-15 seconds. After 15 minutes of initiator addition, monomer solution is added at a rate of about 1 or 2 drops per second.
  • initiator dicumyl peroxide (2.3 g) dissolved in styrene (20 g)
  • the monomer solution consists of styrene (68 g) , ethyl acrylate (130 g) and hydroxyethyl acrylate (22 g) .
  • the initiator addition is complete and the contents of the reactor become a viscous solution ; after 2.5 hours, the addition of monomer is complete at which time a second charge of initiator (0.26 g) is added and the temperature held at 150 °C for an additional 60 minutes.
  • the reaction product is then allowed to cool, and it is recovered from the reactor and measured to have a non-volatile material content of 98 weight percent.
  • the resin is water-white clear, and it is determined by gel permeation chromatography (GPC) to have a weight average molecular weight (M ) of 43,000 and a number average molecular weight (M ) of 13,500 for a polydispersity (M w /M n ) of approximately three.
  • GPC gel permeation chromatography
  • the cure properties of the resin are then determined.
  • Propylene glycol t-butyl ether is used to reduce the viscosity of the resin.
  • Films are prepared which are approximately 38.1 ⁇ m (1.5 mil) thick upon drying in an oven at 196°C (385°F) for 20 minutes.
  • the first film is prepared without the benefit of a catalyst and comprises approximately 60 weight percent of the acrylic polymer of this example and approximately 40 weight percent blocked isocyanate. This film is simply a dried, uncrosslinked resin and it demonstrates deterioration after only 10 double rubs with methyl ethyl ketone (ASTM D 4752-87) .
  • the second film is virtually identical in composition to the first film except it is cured with approximately one weight percent of dibutyl tin diacetate (DBTDA) .
  • DBTDA dibutyl tin diacetate
  • This film does not exhibit any deterioration after more than 100 double rubs with MEK.
  • the third film is modified with about 20 weight percent (based on the weight of the mix) of an epoxy resin (which has an hydroxy equivalent weight of 200) , and the crosslinking is promoted with less than one percent DBTDA. After less than 10 double rubs with MEK, the film exhibits deterioration. However, a similar film in which the crosslinker level is increased by fifty weight percent demonstrates no deterioration after more than 100 double rubs with MEK.
  • Example 2 is repeated except that the amount of initiator is increased to two weight percent ; the monomer solution contains 24 g of styrene, 44.5 g of ethyl acrylate, 7.2 g of hydroxy ethylacrylate and 12 g of dimethylaminoethyl methacrylate (DMAEMA) ; and the weight ratio of acrylic monomer to blocked isocyanate is adjusted to 1:1.
  • the resulting acrylic polymer is measured to have a M- ⁇ of 42,500, a M n of 12,700 for a polydispersity of 3.35.
  • the acrylic polymer is neutralized with 1.1 weight percent lactic acid, and the acrylic polymerization product (blocked isocyanate and neutralized acrylic polymer) is then used to prepare a water dispersion of approximately 70 weight percent water based upon the weight of the dispersion.
  • Example 2 The procedure of Example 2 is repeated. Excess ethanol (12 g recovered from 222 g of blocked isocyanate heated from room temperature to 155 °C over one hour and then held at 155 "C for an additional hour) is stripped from the blocked isocyanate prior to the addition of di-t-amyl peroxide (2.58 g in 10 g of styrene) as the catalyst, and the monomer solution contains 43.64 g of styrene, 99.46 g of ethyl acrylate, 16.1 g of hydroxyethyl acrylate and 26.82 g of DMAEMA.
  • the reaction product is measured to have a non- volatile material (NVM) content of 98 weight percent, the resin is clear, and it is determined by gel permeation chromatography (GPC) to have a weight average molecular weight
  • NVM non- volatile material
  • KL. number average molecular weight of 42,700 and a number average molecular weight (M n ) of 13,400 for a polydispersity (IL./M_) of approximately 3.1.
  • the blocked isocyanate prepared in Example 1 is charged to a 500 ml reactor equipped with a reflux condenser, dean-stark trap, mechanical agitator, nitrogen inlet and temperature controller. The temperature of the reactor is raised to 155 °C with an increased flow of nitrogen to remove any excess ethanol. After approximately one hour at 155 ⁇ -"-C, both initiator solution (7.7 g dicumyl peroxide and 15 g butyl acrylate) and monomer solution (95 g butyl acrylate, 74 g methyl methacrylate, 29 g 2-hydroxyethyl acrylate and 18 g acrylic acid) are added. The initiator solution is added at a rate of approximately one drop every 12-15 seconds.
  • the finished resin e.g. acrylic polymerization product
  • the finished resin is measured to have a non-volatile content of 98 percent and an acid value of 35 mg KOH/gm resin.
  • the finished resin is then neutralized with dimethylethanol amine and dispersed in water to a non-volatile content of 30.2%.
  • Films are then prepared with and without the use of a cure catalyst to evaluate the cure response of the aqueous dispersion.
  • Example 2 The basic procedure of Example 1 is repeated except 1.73 moles of IPDI is reacted with 2.76 moles of propylene glycol monopropyl ether and 0.87 moles of anhydrous ethanol. The resulting blocked isocyanate is a viscous, slightly yellow solution at room temperature void of free isocyanate.
  • HDI 227 g
  • an addition funnel which is attached to a one liter round bottom flask equipped with agitation, reflux condenser, temperature controller, and nitrogen purge and charged with anhydrous methanol (73 g) .
  • the temperature of the flask contents is increased to approximately 70°C.
  • the trimethyl HDI is added to the methanol at a constant rate over a time period of one hour.
  • the addition funnel is rinsed with anhydrous methanol and the reflux condenser is replaced with a distillation column.
  • the temperature of the reactants is gradually increased to 120°C over a period of one hour and maintained at that temperature for an additional one hour.
  • a sample of the reaction product is analyzed for free isocyanate using ASTM D 1638.
  • the free isocyanate is less than 0.1 weight-percent and the amount of non-volatile material in the product is at least 98 weight- percent (based on the total weight of the reaction product) .
  • the blocked diisocyanate (200 g) prepared in Example 7 and 26 g methyl amyl ketone (2-heptanone) are charged to one liter round bottom flask equipped with agitation, nitrogen purge, reflux condenser, temperature controller and two addition funnels.
  • the round bottom flask is heated to a temperature of 155-160°C and then a mixture of 156 g 2-hydroxyethyl acrylate, 147 g styrene and 156 g ethyl acrylate is added at a constant rate from one addition funnel and 29 g di-t-amyl peroxide is added at a constant rate from the other addition funnel at a constant weight ratio of 10:1 over a six-hour time period.
  • the temperature is maintained at 5 160°C for one hour. Then 2.9 g di-t-amyl peroxide is added and the reaction conditions are maintained for an additional one hour. The reactor flask is then permitted to cool to approximately 100 °C, at which time the product is discharged.
  • the product obtained according to this Example is a clear 0 homogeneous solution having a non-volatile material (NVM) content of 90 weight-percent with a viscosity of 58,2 Pa.s (582 poise) at 25°C, and it is determined by gel permeation chromatography (GPC) to have a weight average molecular weight (M ⁇ of 6323 and a number average molecular weight (M ) of 5 2881 for a polydispersity (M ⁇ M ⁇ of approximately 2.2.
  • NVM non-volatile material

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Abstract

L'invention porte sur des systèmes de revêtements à faible teneur en VOC et exempts de HAPS qui comprennent: (i) au moins un isocyanate bloqué par exemple le produit de réaction d'isophorone diisocyanate et d'étanol; (ii) un ou plusieurs polymères acryliques à fonctionnalités hydroxy et époxy, par exemple un polymère d'acrylate d'éthyle, d'acrylate d'hydroxyéthyle, et de styrène; et (iii) de l'eau, ou de l'eau et de la résine, ou un solvant par exemple du tripropylène glycol. Lesdits systèmes de revêtements se préparent: (i) par blocage de l'isocyanate; (ii) par extraction de l'agent de blocage en excès, s'il existe, et (iii) par polymérisation des monomères pour former le polymère acrylique en présence de l'isocyanate bloqué. Ce sont des catalyseurs à l'uréthane qui assurent le durcissement desdits systèmes de revêtements.
PCT/EP1998/002142 1997-04-04 1998-04-06 Systemes de revetements a faible teneur en voc a base de polymeres acryliques et d'isocyanate bloque et leur procede de preparation WO1998045348A1 (fr)

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US60/042,513 1997-04-04

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7358301B2 (en) * 2002-12-17 2008-04-15 Hewlett-Packard Development Company, L.P. Latex particles having incorporated image stabilizers
JP2016053112A (ja) * 2014-09-03 2016-04-14 東洋インキＳｃホールディングス株式会社 熱硬化性樹脂組成物、および太陽電池裏面保護シート
CN111902450A (zh) * 2018-03-30 2020-11-06 阿科玛法国公司 用作具有能基于外部刺激而改变的性质的粘合剂的可固化组合物及其制造方法和用途

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0263983A1 (fr) * 1986-09-16 1988-04-20 Takeda Chemical Industries, Ltd. Compositions de résine à un seul composant et leur durcissement
EP0548690A1 (fr) * 1991-12-20 1993-06-30 BASF Corporation Méthode de revêtement pour vernis clair à un composant avec un isocyanate bloqué
EP0703256A1 (fr) * 1994-09-21 1996-03-27 Dsm N.V. Composition de liant pour peinture en poudre

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0263983A1 (fr) * 1986-09-16 1988-04-20 Takeda Chemical Industries, Ltd. Compositions de résine à un seul composant et leur durcissement
EP0548690A1 (fr) * 1991-12-20 1993-06-30 BASF Corporation Méthode de revêtement pour vernis clair à un composant avec un isocyanate bloqué
EP0703256A1 (fr) * 1994-09-21 1996-03-27 Dsm N.V. Composition de liant pour peinture en poudre

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7358301B2 (en) * 2002-12-17 2008-04-15 Hewlett-Packard Development Company, L.P. Latex particles having incorporated image stabilizers
US8148461B2 (en) 2002-12-17 2012-04-03 Hewlett-Packard Development Company, L.P. Latex particles having incorporated image stabilizers
JP2016053112A (ja) * 2014-09-03 2016-04-14 東洋インキＳｃホールディングス株式会社 熱硬化性樹脂組成物、および太陽電池裏面保護シート
CN111902450A (zh) * 2018-03-30 2020-11-06 阿科玛法国公司 用作具有能基于外部刺激而改变的性质的粘合剂的可固化组合物及其制造方法和用途

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