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
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used 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
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/2815—Monohydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • 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
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
  • C09B67/006—Preparation of organic pigments
  • C09B67/0066—Aqueous dispersions of pigments containing only dispersing agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
  • C09B67/0071—Process features in the making of dyestuff preparations; Dehydrating agents; Dispersing agents; Dustfree compositions
  • C09B67/0084—Dispersions of dyes
  • C09B67/0085—Non common dispersing agents
• • 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
  • C09D17/00—Pigment pastes, e.g. for mixing in paints
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/45—Anti-settling agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K23/00—Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
  • C09K23/16—Amines or polyamines
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/14—Paint wastes

Definitions

• This invention relates to polymeric pigment dispersants prepared by reacting an isocyanate with a hydrophilic poly(ethylene glycol) alkyl ether, a hydrophobic polyester or polyacrylate, and a diamine.
• the materials described in this application are cationic dispersants.
• the cationic substitution allows their use with anionic pigments, particularly carbon black and surface treated organic pigments.
• the use of mixed arms provides broader solubility characteristics and utility with a wider range of coatings vehicles. These materials can therefore be considered "universal dispersants”.
• the present invention differs from prior art dispersants in that it encompasses a unique combination of hydrophobic arm(s), hydrophilic arm(s) and amine arm(s) functionality on an isocyanate backbone.
• the present invention provides a pigment dispersant comprising an isocyanate oligomer having at least three isocyanate groups, wherein (a) at least one of the isocyanate groups has been reacted with a hydrophilic poly(ethylene glycol) alkyl ether, preferably a poly(ethylene glycol) methyl ether;
• At least one of the isocyanate groups has been reacted with a hydrophobic polymer selected from the group consisting of polyesters and polyacrylates, preferably a polyester; and
• At least one isocyanate group has been reacted with a diamine comprising a primary amine and a tertiary amine.
• the isocyanate oligomer may be linear or alicyclic and is chosen from isocyanurates or biurets of toluene diisocyanate("TDI"), hexamethylene diisocyanate (“HDI”), and mixtures thereof.
• the dispersants described herein are the reaction product of a multifunctional isocyanate with a polyester or polyacrylate, a polyethylene ether and a diamine.
• the polyester or polyacrylate and polyethylene ether “arms” have widely different solubility profiles and provide entropic stabilization for the dispersant in a wide range of solvent systems.
• the amine "arm” provides a functional group that can strongly interact with an acidic pigment for dispersion stability.
• the dispersants of this invention comprise the reaction product described above wherein 10 to 50 mole % of the isocyanate groups on the oligomer are reacted with a polyester or polyacrylate, 3 to 30 mole % are reacted with the poly(ethylene glycol) methyl ether and 30 to 65 mole % of the isocyanate groups are reacted with the diamine, with the proviso that 100% of the isocyanate groups are reacted.
• the isocyanate oligomer may be linear, branched or alicyclic.
• Isocyanurates that may be used in this invention to provide the isocyanate oligomer include toluene diisocyanate ("TDI”; Desmodur IL), hexamethylene diisocyanate (“HDI”; Desmodur 3300); mixtures of TDI and HDI (Desmodur HL), and biuret of hexamethylene diamine (Desmodur N). These may be obtained from sources indicated in the Examples.
• the isocyanate oligomers must have an average functionality of three or more, meaning that a molecule of the isocyanate contains, on statistical average, at least three free isocyanate groups.
• the average functionality as opposed to the absolute number of isocyanate groups, is used because the isocyanates are obtained as isomeric mixtures of isocyanates having 3, 4, 5 or more functional groups.
• the average functionality can be determined experimentally by titrating to determine the weight % of isocyanate, determining the number average molecular weight ("Mn") of the oligomer (such as by Gel Permeation Chromatography "GPC”), and then calculating the average number of isocyanate groups.
• Mn number average molecular weight
• the dispersants of this invention are prepared by sequentially reacting the polyester or polyacrylate, the poly(ethylene glycol), and the diamine with the selected isocyanate oligomer. At the conclusion of the synthesis, all of the isocyanate groups have been reacted.
• polyesters suitable for use in the invention have the general formula:
• polyesters are conveniently prepared by reacting caprolactone with an alcohol.
• the length of the polyester arm for any particular dispersion is determined by a balance between its being long enough to give good pigment dispersion and yet not so long that it crystallizes too readily to produce a unstable solution.
• a typical synthesis of the polyester arm using n-decanol and caprolactone, is shown in the following figure:
• Polyacrylates useful in the present invention are hydroxy-terminated (meth)acrylic polymers. Such polymers are prepared by reacting (meth)acrylic monomers with 2-mercaptoethanol in the presence of a free radical initiator. Azo initiators such as azobisisobutyronirile (VAZO® 64, E. I du Pont de Nemours & Co., Wilmington, DE) are particularly useful. Other useful monomer compositions and initiating conditions are described in U.S. Pat. No. 4,032,698, the disclosure of which is incorporated herein in its entirety. The preparation of the polyacrylate arm is illustrated schematically by the following equations:
• n 20 to 50
• Poly(ethylene glycol) alkyl ether polymers useful in this invention are those having the general formula H(O-CH 2 -CH 2 ) n -OR where n is an integer of 15 to 67 and R is an alkyl of 1 to 4 carbons, preferably methyl.
• the poly(ethylene glycol) alkyl ethers have a number average molecular weight ("Mn") between 750 and 3000, preferably between 900 and 2500, and all ranges encompassed therein.
• Mn number average molecular weight
• the poly(ethylene glycol) alkyl ethers have a single hydroxyl functional group. Such polymers are commercially available from
• poly(ethylene glycol) alkyl ether polymers can easily be prepared using conventional techniques well known to those skilled in the art.
• Suitable diamines useful in the invention are those having a primary amine and a tertiary amine. Such diamines have the general formula:
• R, and R 2 are each independently an alkyl of 1 to 4 carbons or together form a saturated or unsaturated 5 to 8 member ring optionally containing N or O.
• diamines which are preferred are:
• l-(3-aminopropyl)imidazole is the most preferred. It has the complexing activity of pyridine, but is more basic. It has a relatively low equivalent weight, and is commercially available. In the experimental results reported herein, it was necessary to use a 10 to 15% calculated excess of isocyanate to ensure complete consumption of all of the diamine used in the last step of the synthesis.
• the dispersants of this invention can thus be schematically illustrated by the figure below, in which a tri-functional isocyanate has been reacted with a diamine, a polyester and a poly(ethylene glycol) methyl ether. It should be recognized that, in accordance with the invention, the polyester could be substituted with a polyacrylate in the figure below.
• the dispersants of this invention are useful in making pigment dispersions and mill bases for paints and other coatings.
• pigments are added to the dispersant and the pigments are dispersed using conventional techniques such as high speed mixing, ball milling, sand grinding, attritor grinding or two or three roll milling.
• the resulting pigment dispersion has a pigment to dispersant binder weight ratio of 100/1 to 100/500.
• any of the conventional pigments used in paints can be used to form the pigment dispersion such as metallic oxides like titanium dioxide, iron oxides of various colors, zinc oxide, carbon black, filler pigments such as talc, china clay, barytes, carbonates, silicates and a wide variety of organic pigments such as quinacridones, phthalocyanines, perylenes, azo pigments, indanthrones, carbazoles such as carbazole violet, isoindolinones, thioindigo reds, benzimidazolinones, metallic flakes such as aluminum flake, pearlescent flakes and the like.
• pigment dispersion It may be desirable to add other optional ingredients to the pigment dispersion such as antioxidants, flow control agents, rheology control agents such as fumed silica, microgels, UV stabilizers, screeners, quenchers and absorbers.
• the pigment dispersions can be added to a variety of solvent borne or aqueous coating compositions such a primers, primer surfacers, topcoats which may be monocoats or basecoats of a clear coat/base coat finish. These compositions preferably have an acrylic polymer or polyester polymer or a blend of these types of coating vehicle as the film forming constituent and may also contain crosslinking agents such as blocked isocyanates, isocyanates, alkylated melamines, epoxy resins and the like.
• Other film forming polymers can also be used, such as acrylourethanes, polyester urethanes, polyethers and polyether urethanes that are compatible with the pigment dispersion.
• the GH viscosity were determined using a comparative set of viscosity standards to obtain a bubble tube match. The method is described in ASTM D 1545-76.
• the standards used were 0.1% of polystyrene of 3.04M, 1.03M, 330K, 156K, 66K, 28.5K, 9.2K, 3.25K, 580 molecular weight. A point to point calibration was used with these narrow molecular weight standards. Tetrahydrofuran was used as the solvent.
• a Waters 410 RI detector (Milford, MA) was used for the measurements. The columns used were from Polymer Laboratories, Inc. (Amherst, MA) (part #1110-6500). The column heater temperature was 30°C. The detector temperature was 35°C. The flow rate was 1.0 ml/min. with an injection volume of 100 ⁇ l of the 0.1% solution of experimental polymer in THF. The samples were filtered through a 0.5 ⁇ m Millipore filter before being run.
• a 2 g sample was diluted with 25 ml of THF. Ten drops of 0.1% bromophenol blue indicator was then added and the solution titrated to a blue to yellow end point with 0.1 N aqueous hydrochloric acid.
• Amine # cc Titrant x Normality x 56.1 /sample wt.
• Example 1 polyester of 6:1 mole ratio of caprolactone to n-decanol The following materials were combined in a 2 liter flask fitted with a stirrer thermocouple and condenser. The condenser was topped with a nitrogen inlet to maintain a constant pressure of nitrogen in the flask.
• the materials were heated with stirring to 140°C over about 25 minutes and held at 140 to 147°C for three hours.
• Example 2 polyester of 9:1 mole ratio of caprolactone to n-decanol
• Example 1 was repeated using 9 moles of caprolactone for every 1 mole of n-decanol. The resulting product was 99.7% solids, had a calculated OH# of 47 and a calculated molecular weight of 1186.
• Example 3 polyester of 10:1 mole ratio of caprolactone to n-decanol
• Example 1 was repeated using 10 moles of caprolactone for every 1 mole of n-decanol.
• the resulting product was 99.6% solids, had a calculated OH# of 43 and a calculated molecular weight of 1300.
• a monohydroxy acrylic arm can be prepared by the following solution feed process:
• part I Charge part I to a 2 liter reactor fitted for reflux and two feed streams. Bring the ethyl acetate to reflux under a nitrogen blanket and concurrently feed part II over 200 minutes and part III over 185 minutes while mantaining reflux. Continue heating at reflux for an additional 30 minutes. Complete conversion of the reactants will occur to produce a clear solution with a 60% nonvolatile content.
• the calculated OH number of the solids is 16.4.
• the estimated end to end length of the product is 8 nanometers.
• the calculated molecular weight is 3421.
• a monohydroxy acrylic arm with lower viscosity and improved solubility in low polarity solvents can be prepared by the following solution feed process:
• n-butyl methacrylate 853.2 Monomer Charge part I to a 2 liter reactor fitted for reflux and two feed streams. Bring the ethyl acetate to reflux under a nitrogen blanket and concurrently feed part II over 200 minutes and part III over 185 minutes while mantaining reflux. Continue heating at reflux for an additional 30 minutes. Complete conversion of the reactants will occur to produce a clear solution with a 60% nonvolatile content.
• the calculated OH number of the solids is 11.62.
• the estimated end to end length of the product is 8 nanometers.
• the calculated molecular weight is 4828.
• the materials for the preparation of the acrylic arms can be obtained from Aldrich Chemical Co.
• a dispersant was prepared by reacting an isocyanate with a polyester and a diamine.
• the comparative dispersant did not contain a poly(ethylene glycol) alkyl ether arm. The following reaction was done at sub- reflux in a nitrogen blanketed reactor. A 1 liter flask was fitted for portionwise addition of the amine solution. The following charge was used:
• Part I was charged to the flask and heated under nitrogen for 2 hours at 70°C. Parts II and III were then added according to the following log:
• the dispersant was at least as good as that of Comparative Example A, but the presence of the poly(ethylene glycol) methyl ether arm makes the dispersant more compatible with polar solvents and water.
• Part I was charged to the flask and headed under nitrogen for 2.5 hours at 70°C. Part II was then added according to the following log. In this experiment, even though the calculation showed that 14.6% excess isocyanate was being used, all of the isocyanate was used up by the charge so that no additional amine was needed (i.e., no Part III was needed as in Comp. Ex. A above).
• Example 7 Example 6 was repeated, except that 4-(3aminopropyl)morpholine was used as the diamine.
• Example 8 Example 6 was repeated except that Desmodur HL was used as the isocyanurate.
• Example 9 Example 8 was repeated except that 3-aminomethyl pyridine was used as the diamine.
• Example 10 Example 8 was repeated except that 3-dimethylamino propylamine was used as the diamine.
• Example 6 was repeated to prepare a dispersant having a higher content of poly(ethylene glycol) methyl ether. Assuming an average isocyanate functionality of 6, the dispersant will contain, on average, 0.5 moles of the hydrophobic polyester arms, 0.9 moles of the hydrophilic poly(ethylene glycol) methyl ether arms and 2.2 moles of the imidazole groups.
• Part I was charged to the flask and headed under nitrogen for 3 hours at 70°C. Although it became fairly viscous, it was still easy to stir. IR indicated an appropriate drop in isocyanate had occurred. Part II was then added over about 3 minutes at about 70 °C. The temperature rose to 75 °C, and the mixture became very viscous. Part III was added, then part IV without preventing the material from becoming gel like. Only when part V was added did the mixture begin to thin and go into solution. It was held for 96 hours at 25 °C with occasional stirring as it dissolved. Finally part VI was added to thin the clear light yellow solution for filtration through a stainless steel mesh paint filter.
• Example 12 Dispersant with Methyl Methacrylate and Methoxy PEO 2000 Arms
• This dispersant can be prepared using the following charge. A theoretical excess of 10% Desmodur IL is included.
• This material will be a good dispersant for acidic pigments and would be particularly suitable for use in acrylic lacquers.

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• Chemical & Material Sciences (AREA)
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• Engineering & Computer Science (AREA)
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• Health & Medical Sciences (AREA)
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• Polymers & Plastics (AREA)
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• Wood Science & Technology (AREA)
• Dispersion Chemistry (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
• Polyurethanes Or Polyureas (AREA)
• Paints Or Removers (AREA)

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• 1999
  • 1999-08-09 US US09/370,416 patent/US6506899B1/en not_active Expired - Lifetime
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