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
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0895—Manufacture of polymers by continuous processes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3225—Polyamines
  • C08G18/3228—Polyamines acyclic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
  • C08G18/348—Hydroxycarboxylic acids
• • 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
  • C08G18/423—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing cycloaliphatic groups
  • C08G18/4233—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing cycloaliphatic groups derived from polymerised higher fatty acids or alcohols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6633—Compounds of group C08G18/42
  • C08G18/6659—Compounds of group C08G18/42 with compounds of group C08G18/34
• • 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
  • C08G18/758—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing two or more cycloaliphatic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
• • 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
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
• • 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

Definitions

• the present invention relates to a process for continuous production of an aqueous polyurethane-polyurea dispersion.
• the process allows for continuous production of respective dispersions with very low content of organic solvents without the need of a step of removing such solvent via distillation.
• Aqueous dispersions of polyurethane and polyurethane-polyurea polymers are well-known in the art. They find broad applicability in versatile industrial branches like, for example, the coating industry.
• the polymers in particular, are used as binder resins in coating materials and decisively influence the properties and quality level of these materials.
• the prior art describes versatile polyurethane and polyurethane-polyurea polymers and its application in, for example, automotive basecoat materials. For being applicable in such applications and fields, an optimal and stable dispersive character with low particle sizes of the dispersed polymer particles is required.
• WO 2014/007915 A1 discloses a method for producing a multicoat automobile finish, using an aqueous basecoat material which comprises an aqueous dispersion of a polyurethane-polyurea resin produced via batch production.
• the use of the basecoat material produces positive effects on the optical properties, in particular a minimizing of gel specks.
• WO 2016/091539 A1 describes high-quality aqueous polyurethane-polyurea dispersion containing microgel particles and its production via batch procedure.
• the dispersions are applied as binder resins in automotive basecoat compositions and contribute to improvement of optical properties like stability against pinholes and pops.
• comparably high amounts of organic solvents need to be applied, ultimately leading to the requirement of having these distilled off in order to obtain an aqueous dispersion with low content of such organic solvents.
• continuous production is in focus of polymer manufactures. Quite obviously, such continuous production depicts inherent advantages compared to batch production procedures, in particular in the context of industrial scale production.
• DE 10 2004 017 436 A1 discloses a complex method of continuous production of an aqueous polyurethane dispersion by production of an aqueous pre-emulsion by mixing a polyurethane prepolymer with water in a mixing nozzle and homogenization of the so produced pre-emulsion in a multi-step homogenizing nozzle.
• EP2157111 B1 discloses a process for production of an aqueous polyurethan urea resin by mixing a polyurethane prepolymer solution with a low amount of organic solvent (ketones) with water, whereby the prepolymer is prepared by use of an amine-neutralized polyhydroxycarboxylic acid, meaning that the prepolymer is already neutralized before being mixed with water.
• This feature is made responsible for enabling a dispersing process of the prepolymer with a very low amount of organic solvent, meaning that the resulting dispersion contains likewise a low content of such solvent without the need of distilling off such solvent. While the document, in general form, describes that the process of dispersing may be conducted both batch-wise and in a continuous approach via a rotor/stator unit, the working examples solely are batch-wise processes.
• raising the temperature of the polymer means high energy consumption and, even more importantly, may lead to side reactions of the isocyanate groups (the latter being particularly prominent when generally applicable neutralizing agents (tertiary amines) are already present at this stage).
• Increasing the amounts of organic solvents in the organic phase results in likewise higher amounts of organic solvent in the resulting aqueous dispersion (and the need of finally distilling off these organic solvents, if a dispersion with low organic volatile content is desired).
• Figure 1 shows a stator (10) having three stator sets of teeth (11) having teeth (12).
• the first set of teeth (11) having the smallest diameter consist of in total 24 teeth having a distance from each other of, for example, 2.0 mm.
• the second set of teeth (11) consist of 34 teeth (1.2 mm distance), while the set (11) with the biggest diameter consists of 160 teeth (0.3 mm).
• the first inlet (13) and second inlets (14) arranged in form of a circle and having uniform distances to each other.
• the figure shows one half of the stator in detail (i.e. with individual teeth (12) and also showing the individual second inlets (14)), while the second half is a schematic figure (set of teeth as circles, individual second inlets not shown).
• Figure 2 shows a rotor (20) having four rotor sets of teeth (21) having teeth (22).
• the first set of teeth (21) having the smallest diameter consist of 12 teeth in total having a distance from each other of, for example, 3.0 mm.
• the second set of teeth (20) consist of 28 teeth (1.6 mm distance), while the third set (20) consists of 70 teeth (0.6 mm).
• the fourth set of teeth (20) having the biggest diameter consists of 160 teeth (0.3 mm).
• one half is a detailed figure, while the other half is of schematic character.
• Figure 3 shows rotor/stator unit as overlap of Figures 1 and 2, thereby explicitly referring to the first inlet (13), two second inlets (14), the three stator sets of teeth (11) and the four rotor sets of teeth (21). Furthermore, the stator sets of teeth and three rotor sets of teeth are specified according to their position relative to the set of second inlets. Therefore, sets of rotor teeth to which the second inlets are positioned radially outside are named rotor sets of teeth (21a), while respective stator sets of teeth are named stator set of teeth (11a). Also, sets of rotor teeth to which the second inlets are positioned radially inside are named rotor sets of teeth (21b), while respective stator sets of teeth are named stator set of teeth (11b).
• an organic-based phase (I) is provided.
• the organic-based phase (I) comprises at least one polyurethane prepolymer (a) containing isocyanate groups.
• polyurethane polymers containing isocyanate groups are known in principle.
• the respective component (a) is referred to as prepolymer, for greater ease of comprehension.
• This component is in fact a polymer (or oligomer) which can be referred to as a precursor, since it is used as a starting component for preparing another component, specifically the polyurethane-polyurea polymer within the aqueous dispersion.
• polyurethane prepolymers which contain isocyanate groups and comprise anionic groups and/or groups which can be converted into anionic groups
• diisocyanates 1 ,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'- or 2,4'-diphenylmethane diisocyanate, 1 ,4- or 1,5-naphthylene diisocyanate, diisocyanatodiphenyl ether, trimethylene diisocyanate, tetramethylene diisocyanate, ethylethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1 -methyltrimethylene diisocyanate, pentamethylene diisocyanate, 1 ,3-cyclopentylene diisocyanate, hexamethylene diisocyanate, cyclohexylene diisocyanate, 1 ,2-cyclohexylene diisocyanate, octamethylene diisocyanate, trimethylhexane diiso
• dimers and trimers of the stated diisocyanates such as uretdiones and isocyanurates.
• Polyisocyanates of higher isocyanate functionality may also be used. Examples thereof are tris(4- isocyanatophenyl)methane, 1,3,4-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 1 ,3,5- tris(6-isocyanatohexylbiuret), bis(2,5-diisocyanato-4-methylphenyl)methane.
• the functionality may optionally be lowered by reaction with monoalcohols and/or secondary amines.
• diisocyanates more particularly to using aliphatic diisocyanates, such as hexamethylene diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane 4, 4'-diisocyanate, 2,4- or 2,6-diisocyanato-1-methylcyclohexane, and m- tetramethylxylylene diisocyanate (m-TMXDI).
• IPDI isophorone diisocyanate
• m-TMXDI m- tetramethylxylylene diisocyanate
• An isocyanate is termed aliphatic when the isocyanate groups are attached to aliphatic groups; in other words, when there is no aromatic carbon present in alpha position to an isocyanate group.
• the prepolymers (a) are prepared by reacting the stated polyisocyanates with polyols, more particularly diols, generally with formation of urethanes.
• polyols examples are the generally known polyester, polycarbonates, polyether, polydiene, polyene, poly(meth)acrylate and/or polysiloxane polyols, more particularly diols. Mixtures of polyols are likewise possible.
• polyester polyols are saturated or olefinically unsaturated polyester polyols and/or polyether polyols.
• Polyols used more particularly are polyester polyols, especially those having a number-average molecular weight of 400 to 5000 g/mol (for measurement method, see Example section).
• Such polyester polyols, preferably polyester diols may be prepared in a known way by reaction of corresponding polycarboxylic acids, preferably dicarboxylic acids, and/or their anhydrides with corresponding polyols, preferably diols, by esterification. It is of course optionally possible in addition, even proportionally, to use monocarboxylic acids and/or monoalcohols for the preparation.
• the polyester diols are preferably saturated, more particularly saturated and linear.
• polyester polyols examples include polyester diols, are phthalic acid, isophthalic acid, and terephthalic acid, of which isophthalic acid is advantageous and is therefore used with preference.
• Suitable aliphatic polycarboxylic acids are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid, or else hexahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic acid, tricyclodecanedicarboxylic acid, and tetrahydrophthalic acid.
• dimer fatty acids or dimerized fatty acids which, as is known, are mixtures prepared by dimerizing unsaturated fatty acids and are available, for example, under the commercial names Radiacid (from Oleon) or Pripol (from Croda).
• Radiacid from Oleon
• Pripol from Croda
• the use of such dimer fatty acids for preparing polyester diols is preferred.
• Polyols used with preference for preparing the prepolymers (a) are therefore polyester diols which have been prepared using dimer fatty acids.
• polyester polyols for preparing polyester polyols, preferably polyester diols, are ethylene glycol, 1 ,2- or 1 ,3-propanediol, 1 ,2-, 1 ,3-, or 1 ,4-butanediol, 1 ,2-, 1 ,3-, 1 ,4-, or 1 ,5- pentanediol, 2,2-dimethyl-1 ,3-propanediol (neopentylglycol), 2-methyl-2,4-pentanediol, 1 ,2-, 1,3-, 1 ,4-, 1 ,5-, or 1 ,6-hexanediol, trimethylpentanediol, 1 ,2-, 1 ,3-, or 1 ,4-cyclohexanediol, 1 ,2- , 1 ,3-, or 1 ,4-cyclohexanedimethanol, bifunctional alcohol
• corresponding polyols for preparing polyester polyols are polyols based on the hydrogenation products of methylesters of polycarboxylic acids which are derived from dimeric and trimeric fatty acids, for example, the dimer fatty C36 diol after hydrogenation of the methylester of saturated dimeric C36 fatty acid (Pripol® 2033; from Croda)
• More examples of corresponding polyols for preparing polyester polyols, preferably polyester diols are ether Oder cyclic ether alcohols like, diethylene glycol, triethylene glycol, tetraethylene glycol, 2,5- bis(hydroxymethyl)furane, 2,5-bis(hydroxymethyl)terahydrofurane, as well as carbohydate- based cyclic etheralcohols such as isosorbide, isomannide, and isoidide, and ester alcohols like 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-d
• Polyhydroxy-polyesters which are derived from polyhydroxyalkyl acids, like poly 2- hydroxyethanoic acid (polyglycolic acid) or polyhydoxypropionic acid, its other name is poly(lactic acid) (polylactides), and polyhydroxyalkyl acids with higher number of carbon atoms can also be used.
• the direct method is based on the direct polycondensation of hydroxycarboxylic acids as alpha, beta, gamma or omega-hydroxylic acids.
• examples of corresponding hydroxycarboxylic acids are 2-hydroxyethanoic acid (glycolic acid), 2-hydroxypropionic acid, 3-hydroxypropionic acid (lactic acid), 3-hydroxy-2-methylpropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 3-hydroxypentanoic acid, 5-hydroxypentanoic acid up to 12- hydroxydodecanoic acid (sabinic acid) or 13-hydroxytridecanoic acid.
• polyester diols based on polyhydroxyalkyl acids by ring-opening polymerization of cyclic oligomers, prefered dimers, of the corresponding hydroxycarboxylic acids, for example dilactides from corresponding lactic acid to form the best-known biodegradable polymer poly(lactic acid)
• polyester diol is also to be understood as meaning polylactone diols, obtained by reaction of a lactone with polyol as an initiator that has active hydrogen-containing groups; illustrative of which is ethylene glycol, diethylene glycol, propanediols, 1,4-butanediol, 1 ,5- pentandiol or 1 ,6-hexanediol, and generated by ring opening polymerization.
• Lactones which can be used for the synthesis of the polyester polyols are butyrolactone, valerolactone, methylvalerolactone, caprolactone, methylcaprolactone, and 2-oxocanone (enantholactone).
• the preferred lactone polyols are known as polycaprolactone polyols.
• polycarbonate polyols are polycarbonate polyols, more particularly polycarbonate diols.
• These polycarbonate polyols can be prepared by reaction of polyols, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2-methylpentane-1,3-diol, neopentylglycol, 1,6-hexanediol, 2,2,4-trimethylpentane-1,3-diol, 2-butyl-3-ethylpropan-1 ,3- diol, trimethylolpropane or pentaerythritol, 1 ,4-bishydroxymethylcyclohexane, 2,2-bis(4- hydroxycyclohexyl) propane, diethylene glycol, triethylene glycol or tetraethylene glycol, with di-carbonates, such as dimethyl, diethyl or diphenyl carbonate, or pho
• oligomeric or polymeric hydroxy-functional compounds are polydiene or polyene, and there are at least two, preferably terminal, hydroxyl groups per molecule.
• polyether polyols examples include polyols of polyoxyethylene, polyoxypropylene polyoxybutylene, mixed and block copolymers of these, in blocks or randomly distributed along the polymer chain, and, polyoxytetramethylene (polytetrahydrofurane, for example PolyTHF 2000 from BASF SE) containing terminal OH groups, also simply known as glycols. Again, diols are preferred.
• Eligible polyols are further exemplified by alpha, omega - dihydroxy poly(meth)acrylates (for example TEGO® Diol MD 1000 of Evonik Tego Chemie GmbH) and alpha, omega - polydialkylsiloxane diols, like polydimethylsiloxane diols.
• alpha, omega - dihydroxy poly(meth)acrylates for example TEGO® Diol MD 1000 of Evonik Tego Chemie GmbH
• alpha, omega - polydialkylsiloxane diols like polydimethylsiloxane diols.
• Diols are used with preference.
• the prementioned polyols and/or diols may of course also be used directly for preparing the prepolymer (a), in other words reacted directly with polyisocyanates.
• polyamines such as diamines and/or amino alcohols.
• diamines include hydrazine, alkyl- or cycloalkyldiamines such as propylene diamine and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane
• amino alcohols include ethanolamine or diethanolamine.
• the prepolymers (a) preferably comprise anionic groups and/or groups which can be converted into anionic groups (that is, groups which can be converted into anionic groups by the use of known neutralizing agents, and also neutralizing agents specified later on below, such as bases).
• these groups are, for example, carboxylic, sulfonic and/or phosphonic acid groups, especially preferably carboxylic acid groups (functional groups which can be converted into anionic groups by neutralizing agents), and also anionic groups derived from the aforementioned functional groups, such as, more particularly, carboxylate, sulfonate and/or phosphonate groups, preferably carboxylate groups.
• the introduction of such groups is known to increase the dispersibility in water.
• the stated groups may be present proportionally or almost completely in the one form (carboxylic acid, for example) or the other form (carboxylate).
• One particular influencing factor resides, for example, in the use of the neutralizing agents which have already been addressed and which are described in even more detail later on below. If the prepolymer (a) is mixed with such neutralizing agents, then an amount of the carboxylic acid groups is converted into carboxylate groups, this amount corresponding to the amount of the neutralizing agent. Irrespective of the form in which the stated groups are present, however, a uniform nomenclature is frequently selected in the context of the present invention, for greater ease of comprehension.
• a particular acid number is specified for a polymer, such as for a prepolymer (a), or where such a polymer is referred to as carboxy-functional
• this reference hereby always embraces not only the carboxylic acid groups but also the carboxylate groups. If there is to be any differentiation in this respect, such differentiation is dealt with, for example, using the degree of neutralization.
• Corresponding compounds contemplated for introducing the preferred carboxylic acid groups are polyether polyols and/or polyester polyols, provided they contain carboxyl groups.
• compounds used with preference are at any rate low molecular weight compounds which have at least one carboxylic acid group and at least one functional group reactive toward isocyanate groups, preferably hydroxyl groups.
• the expression "low molecular weight compound", as opposed to higher molecular weight compounds, especially polymers should be understood to mean those to which a discrete molecular weight can be assigned, as preferably monomeric compounds.
• a low molecular weight compound is thus, more particularly, not a polymer, since the latter are always a mixture of molecules and have to be described using mean molecular weights.
• the term "low molecular weight compound” is understood to mean that the corresponding compounds have a molecular weight of less than 300 g/mol. Preference is given to the range from 100 to 200 g/mol.
• the prepolymers (a) are carboxy-functional. They preferably possess an acid number of 10 to 35 mg KOH/g, more particularly 15 to 23 mg KOH/g (based on solids content).
• the prepolymer (a) preferably is build-up from difunctional compounds like, in particular, diisocyanate and diols. Therefore, it is evident that the prepolymer preferably is of linear character.
• the prepolymer (a) contains isocyanate groups.
• the polyurethane prepolymer preferably has an isocyanate equivalent weight of below 3000 g/mol. More preferably, the isocyanate equivalent weight is below 2500 g/mol. Preferred ranges are from 500 to 3000 g/mol, even more preferably from 1000 to 2500 g/mol (determined via NCO content of the prepolymer (solids content)).
• the prepolymer (a) has a number-average molecular weight of at most 6000 g/mol, for example in the range from 1000 to 6000 g/mol, more preferably from 2000 to 5000 g/mol.
• the comparably low molecular weight contributes to a likewise low viscosity of the prepolymer, meaning that a more aligned viscosity with the below-described aqueous phase (II) and, therefore, an enhanced dispersibility is reached.
• the prepolymers (a) may be prepared by known and established methods in bulk or solution, especially preferably by reaction of the starting compounds in organic solvents, such as preferably methyl ethyl ketone, at temperatures of, for example, 60 to 120°C, and optionally with use of catalysts typical for polyurethane preparation.
• organic solvents such as preferably methyl ethyl ketone
• catalysts typical for polyurethane preparation.
• Such catalysts are known to those skilled in the art, one example being dibutyltin laurate.
• the procedure here is of course to select the proportion of the starting components such that the product, in other words the prepolymer (a), contains isocyanate groups.
• the solvents ought to be selected in such a way that they do not enter into any unwanted reactions with the functional groups of the starting compounds, in other words being inert toward these groups to the effect that they do not hinder the reaction of these functional groups.
• the preparation is preferably actually carried out in an organic solvent (b) as described below.
• the fraction of organic solvent for preparing the prepolymer (a), based on synthesis mixture (i.e. mixture containing starting compounds and organic solvents) preferably does not exceed the fraction of organic solvents (b) in the organic-based phase as defined below.
• the organic-based phase (I) may also comprises at least one organic solvent (b). Quite obviously, this organic solvent may be the one or those applied within the manufacturing process of the prepolymer (a). Regarding the organic solvents (b), those being known to the person skilled in the art may be applied and no particular restrictions apply. For example, as solvents (b) ketones, ether, ester, pyrrolidones, amides, morpholines, lactones, acetates or sulfoxides may be applied.
• solvents (b) are methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, diethyl ether, dibutyl ether, dipropylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dibutyl ether, diglycol acetate, toluene, methyl acetate, ethyl acetate, butyl acetate, propylene carbonate, cyclohexanone, acetone, N-methyl-2-pyrrolidone, N-ethyl-2- pyrrolidone, tetra hydrofuran, dioxane, N-formylmorpholine, dimethylformamide, or dimethyl sulfoxide, 3-methoxy-N,N-dimethyl propione amide, 3-butoxy-N,N-dimethyl propione amide, N-formyl morpholine, gamma
• the fraction of the at least one organic solvent (b) is not more than 20 % by weight (20 wt.-%), based on the total weight of the organic-based phase (I). Therefore, the organic-based phase (I) may even be entirely free of such organic-solvent (meaning that in such a case the organicbased phase may consist of the prepolymer (a)).
• the fraction of the at least one organic solvent (b) preferably is not less than 5 % by weight.
• the fraction is from 5 to 20 % by weight, more preferably from 10 to 15 % by weight, in each case based in the total weight of the organic-based phase.
• the solids content of the organic-based phase (I) preferably is at least 80 % by weight, more preferably at least 85 % by weight, but preferably below 90 % by weight. Preferred ranges are from 80 to 95 % by weight like, for example, 85 to 90 % by weight.
• Neutralizing agents contemplated include, in particular, the known basic neutralizing agents such as, for example, carbonates, hydrogencarbonates, or hydroxides of alkali metals and alkaline earth metals, such as LiOH, NaOH, KOH, or Ca(OH)2 for example.
• organic bases containing nitrogen such as amines, such as ammonia, trimethylamine, triethylamine, tributylamines, dimethylaniline, triphenylamine, dimethylethanolamine, methyldiethanolamine, or triethanolamine, and also mixtures thereof, as well as and also alkali metals.
• the neutralization of the prepolymer (a) with the neutralizing agents, more particularly with the nitrogen-containing organic bases, may take place after the preparation of the prepolymer in organic phase, in other words in solution with an organic solvent, more particularly a solvent (b) as described above.
• the neutralizing agent may of course also be added during or before the beginning of the actual polymerization, in which case, for example, the starting compounds containing carboxylic acid groups are neutralized.
• the neutralization and thus addition of neutralizing agents to the prepolymer (and successively forming aqueous polyurethane dispersion, respectively) may take place during and/or after dispersing the organic-based phase (I) with the aqueous phase (II).
• an aqueous phase (II) is provided in the second step (2) of the process of the invention. Quite obviously, the second step may take place before or after or in parallel to the first step (1).
• the aqueous phase (II) apparently, comprises water. Besides water, of course, the aqueous phase may also include, proportionally, typical auxiliaries such as typical emulsifiers and protective colloids.
• typical auxiliaries such as typical emulsifiers and protective colloids.
• suitable emulsifiers and protective colloids is found in, for example, Houben Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], volume XIV/1 Makromolekulare Stoffe [Macromolecular compounds], Georg Thieme Verlag, Stuttgart 1961 , p. 411 ff.
• the aqueous phase may include neutralizing agents like in particular nitrogen-containing organic bases or hydroxides of alkali metals, meaning that in this embodiment neutralization at least partly takes place when bringing into contact the aqueous phase and the organic phase, i.e. neutralization takes place during the dispersing procedure.
• neutralizing agents like in particular nitrogen-containing organic bases or hydroxides of alkali metals, meaning that in this embodiment neutralization at least partly takes place when bringing into contact the aqueous phase and the organic phase, i.e. neutralization takes place during the dispersing procedure.
• step (3) of the process of the invention the organic-based phase (I) and aqueous-based phase (II) are continuously fed into a high shear dispersion device comprising a rotor/stator unit. It is essential that the two phases are brought into contact within the rotor/stator unit and thus not before reaching this rotor/stator unit.
• a high shear dispersion device comprises one rotor/stator unit. In the unlikely case that more than one such unit is present in the device, the above-mentioned rotor/stator unit of course is the first unit into which both the organic-based phase (I) and aqueous-based phase (II) are fed.
• High shear dispersion devices comprising rotor/stator units as well as their application for continuous dispersing processes are well known in the art.
• EP 1 489 130 B1 or US 8,669,401 B2 describe details on such units in the context of continuous production of polyurethane emulsions or wax dispersions.
• such rotor/stator units comprise a rotor subunit and a stator subunit.
• Both the rotor and stator subunit comprise at least one set of teeth, whereby the teeth of each set are assembled circumferentially on a circle with a certain circumference and diameter, respectively.
• the at least one set of the rotor and the at least one set of the stator are aligned to each other in a way that the respective teeth of rotor and stator (each describing a circle) are oriented concentrically to each other.
• the sets of teeth of rotor and stator are arranged alternatingly.
• the to be dispersed liquid components are centrically introduced into the device and respective rotation of the rotor results in exposing the liquids to a centrifugal force, ultimately pushing the medium outwards.
• the rotor movement also leads to rotation of the rotor teeth against the fixed teeth of the stator and thus exposing shear to the liquids when flowing outwards through the respectively dynamically changing cavities / cavity sizes of the unit. More specifically, the dynamic changing of the cavities I the size of cavities is based on the mentioned rotation of the rotor teeth against the stationary stator teeth.
• the rotor/stator unit comprises at least two sets of teeth of a rotor (21) and at least two sets of teeth of a stator (11). Even more preferably, at least three sets of teeth of a rotor (21) and at least three sets of teeth of a stator (11). Even more preferably, four sets of teeth of a rotor (21) and three set of teeth of a stator (11) are comprised. As mentioned above, the set of teeth of rotor (21) and set of teeth of stator (11) are of course arranged alternatingly.
• the first set of teeth of the rotor (21) has the overall smallest diameter (thus lying most centrically) and the fourth set of teeth (21) has the overall biggest diameter (thus lying hair outwards).
• the two phases namely the organic-based phase (I) and the aqueous phase (II), are brought into contact within the rotor/stator unit and thus not before reaching this rotor/stator unit. Accordingly, quite obviously, a first requirement is that the two phases are separately supplied as two separate feed streams via two separate inlets into the high shear dispersion device and thus into the rotor/stator unit.
• the organic phase (I) is fed in form of multiple sub feed streams via multiple inlets into the rotor/stator unit. Therefore, the organic phase (I), for example initially provided as one (main) feed stream, is split into multiple sub feed streams before reaching the rotor/stator unit and thus is supplied as such multiple sub feed streams into the unit.
• the two separate feed streams (3.1) ensure a continuous, constant and controllable feeding of both phases into the unit (contrary to a single feed stream comprising both phases, as in this scenario the viscosity difference of the two phases impedes such continuous, constant and controllable feeding), while the feeding of the organic phase in form of multiple sub feed streams (3.2) serves for enhanced dispersing effectiveness.
• the above principle involves one first inlet into the rotor/stator unit being located centrically within unit, i.e. inside the circle described by the smallest und thus most inside set of teeth (which is either a set of teeth of the rotor or of the stator).
• the inlet is part of the stator. Accordingly, this first aspect is equal to the inlet of a standard rotor/stator unit. This first inlet is provided for the aqueous phase (II) and the feed stream of the aqueous phase (II), respectively.
• the novel process involves feeding the organic phase (I) via multiple inlets.
• These inlets may also be named second inlets.
• These multiple inlets i.e. multiple second inlets or set of second inlets
• the inlets are part of the stator.
• the set of second inlets result from a partition of one main inlet pipe into the rotor/stator unit. In other words, one main feed line is split into a respective number of supply inlets.
• the number of second inlets making up the set of second inlets preferably is at least 5, more preferably at least 10 or even at least 20.
• second inlets depends on further factors like overall size of the respective rotor/stator unit or size (i.e. inner diameter) of the inlets.
• the inner diameter of the second inlets also may vary and be selected according to individual needs.
• an appropriate size of second inlets may be influenced by the viscosity of the organic phase (I) or its mass flow. Exemplary size ranges (without implying any limitation, but only a preference) may be from 1.5 to 10 mm like for example 1.8 to 7.5 mm or 1.8 to 5 mm (inner diameter).
• the set of second inlets may be arranged in different types and manner.
• the second inlets as part of the stator may be located, for example, between the central first inlet and the first set of teeth of the stator (i.e. the set of teeth of the stator with the smallest diameter). Also, the second inlets may be located between two sets of teeth of the stator. Obviously, also a first portion of the second inlets may be located between the central first inlet and the first set of teeth of the stator, while a second portion is located between two sets of teeth of the stator (or the second portion may even be divided into groups of inlets located between different pairs of set of teeth of the stator). It is preferred that at least a portion of the second inlets, more preferably all of the second inlets, are positioned between two sets of teeth of the stator.
• the second inlets are located circumferentially on a circle with a certain circumference and diameter.
• the second inlets preferably are uniformly distributed overthe above-named circle, i.e., are positioned on such a circle in uniform distance to each other. From the above follows that it is preferred that this circle has a circumference and thus diameter lying between the circumference and thus diameter of one first set of teeth of the stator and the circumference and thus diameter of one second set of teeth of the stator, meaning that the second inlets are positioned between two sets of teeth of the stator.
• the set of second inlets is a set of inlets (i.e. holes) located circumferentially on a circle having a circumference and diameter being greater than the circumference and diameter of at least one set of stator teeth and at least one set of rotor teeth.
• a portion of second inlets are positioned radially outside of at least one set of rotor teeth and at least one set of stator teeth like, for example, radially outside of two sets of rotor teeth and one set of stator teeth (lying between the two sets of rotor teeth).
• sets of rotor teeth to which the second inlets are positioned radially outside may be named rotor sets of teeth (21a), while respective stator sets of teeth may be named stator set of teeth (11a).
• the second inlets are located at positions where a fluid entering the unit via the first inlet (i.e. the aqueous phase (II)) is passing by in form of already having been exposed to shear via the unit.
• the sets of rotor and stator teeth in a rotor/stator device are located concentrically to each other and, in case of more than one set of teeth of rotor and/or stator, the sets of teeth of rotor and stator are arranged alternatingly
• the set of second inlets as part of the stator preferably are located on a circle also at least substantially describing a circle of a set of rotor teeth (cf. Figure 3). Therefore, the set of second inlets (being holes in the stator) lie directly or approximately (i.e. slightly staggered) beneath the teeth of the respective rotor set of teeth.
• the respective spaces defined by these conditions then are the areas where a first fluid entering the unit via the first inlet is brought into contact with a second fluid entering the unit via the set of second inlets.
• the organic phase (I) entering the unit via the set of second inlets needs to be effectively dispersed with the aqueous phase (II) and thus needs to be effectively exposed to shear to effect appropriate dispersibility character.
• the rotor/stator unit comprises at least one combination of a set of rotor teeth and a set of stator teeth radially outside of the positions of the second inlets. Therefore, in the case where the set of second inlets is arranged as a circle, the circumference and diameter of this circle is smaller than the circumference and diameter of at least one set of stator teeth and at least one set of rotor teeth.
• a portion of the second inlets are positioned radially inside of at least one set of rotor teeth and at least one set of stator teeth like, for example, radially inside of two sets of rotor teeth and two sets of stator teeth (arranged alternatingly).
• sets of rotor teeth to which the second inlets are positioned radially inside may be named rotor sets of teeth (21b), while respective stator sets of teeth may be named stator set of teeth (11b).
• the viscosity of the organic phase comprising a polyurethane-prepolymer and a comparably low solvent content will be significantly higher than the viscosity of the aqueous phase.
• the above setup copes with these hurdles, i.e., guarantees an effective dispersion process despite respective deviations of viscosities of the to be mixed phases.
• the organic phase may be heated before being introduced into the high shear dispersion device and thus rotor/stator unit.
• the temperature of the organic phase (I) when being introduced into the rotor/stator unit and when being brought into contact with the aqueous phase (II), is of at least 50°C, more preferably of at least 65°C or even at least 75°C. Preferred ranges are from 50 to 160°C, more preferably 65 to 140°C or even 75 to 120°C.
• the organic phase when being introduced into the rotor/stator unit preferably has a viscosity of below 35 Pas, preferably 15 to 30 Pas (measured via rotational viscosimeter at a shear rate of 10/s). This viscosity may be reached when heating the organic phase to a temperature as mentioned above.
• the temperature of the aqueous phase (II), when being introduced into the rotor/stator unit and when being brought into contact with the organic phase (I), is of below 25°C, more preferably of below 15°C or even of below 10°C. Preferred ranges are from 1 to 15°C, more preferably 2 to 10°C. As generally known, at such temperatures the viscosity of water and thus of an aqueous phase (II) will be significantly lower than the viscosity of the above-mentioned organic phase (I) (for example, below 10 mPas at a shear rate of 1000/s).
• the preferably low temperature of the aqueous phase serves for a compensation of the preferably higher temperature of the organic phase, meaning that after bringing the phases into contact and thus starting the continuous dispersion step (4) of the process of the invention, the emerging aqueous polyurethane-based dispersion may have a moderate temperature.
• the rotor/stator unit or parts thereof may be cooled by external measures. The same, in principle, applies for the fluid pipe system in connection with the outlet of the rotor/stator unit.
• the temperature also depends on the weight ratio and thus mass flow of the two different phases during production of the aqueous polyurethane-based dispersion, but preferably is between 30 to 80°C or even 40 to 70°C when leaving the rotor/stator unit.
• One reason is that - differently to the prepolymer and organic-based phase (I) - the emerging aqueous dispersion often has a higher viscosity at higher temperatures, meaning that too high temperature may lead to inappropriate flow.
• the ratio of the mass flow of the organic phase (I) and the mass flow of the aqueous phase (II), when entering the rotor/stator unit, may be selected according to individual needs like, for example, the desired solids content of the resulting dispersion.
• the ratio (l):(ll) may be, for example, 1 :4 to 1.5:1.
• the (potentially) anionic groups being initially present in the polyurethane prepolymer are at least partly neutralized before, during or after the dispersing process of the invention.
• at least partly neutralization is conducted during and/or after the dispersing process.
• the “dispersing process” means the step of actual dispersion according to steps (3) and (4) of the process of the invention, i.e. the steps where the two phases are brought into contact and then dispersed within the rotor/stator unit.
• a neutralization is conducted after the dispersing process, this may be conducted, for example, by simple addition of neutralizing agent (for example in form of an aqueous solution) into a final holding vessel for the to be produced aqueous polyurethanepolyurea dispersion or in form of a continuous feeding via a T joint in the pipe system, for example.
• neutralizing agent for example in form of an aqueous solution
• the aqueous phase (II) contains a neutralization agent.
• Preferred neutralization agents are nitrogen-containing organic bases and hydroxides of alkali metals, more preferably nitrogen-containing organic bases. In the here described embodiment, it is likewise preferred that no neutralization agents are added before the dispersing process, e.g. during formation of the prepolymer or directly thereafter.
• a two-step neutralization process i.e. a first neutralization step during the dispersing step and a second neutralization step after the dispersing step, preferably in form of an addition of neutralization agent to the final collecting vessel.
• first neutralization step thus preferably is conducted at a temperature of the to be neutralized mixture of 30 to 80°C or 40 to 70°C.
• the second neutralization step is preferably conducted at a temperature of the to be neutralized mixture of below 35°C like for example 10 to 30°C (i.e. room temperature).
• the degree of neutralization realized in the first step is preferably between 50 and 70 %, while the degree of neutralization realized in the second step is from above 70 to 95 % (as sum of the first and second step) (degree of neutralization in each case calculated as molar ratio of existing potentially anionic groups in the prepolymer and the amount of neutralizing groups in the applied neutralization agent (cf. example section for further details), always considering the respective mass flows of the respective phases in the continuous process).
• the degree of neutralization of the finally resulting aqueous polyurethane-polyurea dispersion preferably is from above 70 to 95 %.
• While neutralization may be relevant for stabilizing the aqueous polyurethane-polyurea dispersion, addition of the agent at different temperatures and/or conditions/reaction progresses during the inventive process may have influence on viscosity and particle size of the final aqueous polyurethane-polyurea dispersion.
• the above preferred embodiments take care of optimizing the resulting aqueous polyurethane-polyurea dispersion in view of these influences.
• an aqueous dispersion comprising polyurethane- based species is formed.
• an amount of isocyanate groups of the prepolymer will react with water to form primary amino groups.
• These emerging amino groups then, will react in turn with remaining isocyanate groups of the prepolymer.
• These reactions will unavoidably take place as of the moment of bringing the two phases (I) and (II) into contact with each other, i.e. within the rotor/stator unit and also during and after continuously discharging the aqueous polyurethane-based dispersion from the high shear dispersion device within step (5) of the process of the invention.
• step (6) of the process of the invention at least one chain extension agent is continuously fed to the aqueous polyurethane-based dispersion discharged from the rotor/stator unit, thereby producing the aqueous polyurethane-polyurea dispersion.
• the chain extension agent reacts with the polyurethane-based species in the polyurethane-based dispersion, more particularly with isocyanate groups of these polyurethane-based species. Therefore, quite obviously, it has to be taken care that an amount of isocyanate groups will remain for reaction with the chain extension agent.
• step (6) at least one chain extension agent is fed to the aqueous polyurethane-based dispersion discharged from the rotor/stator unit, meaning that a chain extension reaction with isocyanate is conducted.
• chain extension agents those agents being established and known to the person skilled in the art may be applied. Therefore, the chain extension agents have N-H functionality, e.g. in form of primary or secondary amino groups or a hydrazine moiety.
• exemplary chain extension agents are aliphatic, aromatic, or araliphatic (mixed aliphatic-aromatic) polyamines like diamines or triamines and also hydrazine or hydrazides.
• Explicit examples are ethylene diamine (EDA), diethylene triamine (DETA), 3-(2- aminoethylamino)propylamine (N3-Amine), dipropylene triamine (DPTA), triethylene tetramine (TETA), N,N’-bis-(3-aminopropyl)ethylene diamine (N4-Amine), meta-xylylenediamine (MXDA), N-(2-aminoethyl) ethanolamine (AEEA), N-(2-aminoethyl) propanolamine (AEPA), 2- methyl pentane diamine, and the like, and mixtures thereof.
• EDA ethylene diamine
• DETA diethylene triamine
• DPTA 3-(2- aminoethylamino)propylamine
• TETA triethylene tetramine
• N4-Amine triethylene tetramine
• MXDA meta-xylylenediamine
• AEEA N-(2-aminoe
• Also suitable for practice in this invention are 1 ,2-propane diamine, 1 ,3-propane diamine, 1 ,3-butane diamine, 1 ,4-butane diamine, 2,2-dimethylpropane-1,3-diamine, 1 ,6-hexamethylene diamine, octamethylene diamine, dimeric fatty acid (C36) diamine, 1 ,2-cyclohexane diamine, 1 ,4-cyclohexane diamine, 2-methyl cyclohexane-1,3-diamine, 4-methyl cyclohexane-1,3-diamine, 3- (cylohexylamino)propyl amine, 4,4’-dicyclohexylmethane diamine, 2,4’--dicyclohexylmethane diamine, 3,3’-dimethyl-4,4’-dicyclohexylmethane diamine, 3,3’-dimethyl-2,4’- dicycl
• Preferred chain extension agents are polyamines having at least three amino groups like for example at least two primary amino groups and at least one secondary amino group. Even more preferably, exactly three amino groups are present, more particularly two primary amino groups and one secondary amino group.
• One preferred polyamine is diethylene triamine.
• the chain extension agent is preferably fed in form of an aqueous composition to the aqueous polyurethane-based dispersion being discharged from the high shear dispersion device and rotor/stator unit, respectively.
• the aqueous composition may be a solution or dispersion of the chain extension agent in water having a concentration of the chain extension agent of between 5 and 20 % by weight, based on the composition.
• the feeding of the aqueous composition takes place in a continuous manner.
• concentration of the chain extension agent may depend on different aspects like mass flow of aqueous polyurethane-based dispersion being discharged from the high shear dispersion device, concentration of the polyurethane-based species in the dispersion, isocyanate content of the polyurethane-based species or mass flow of the composition containing the chain extension agent. In sum, these parameters are adjustable according to individual needs.
• the continuous feeding of the chain extension agent may be conducted via a T joint in the pipe system.
• a mixing device like a static mixer may be positioned in the system after the point where the chain extending agent is fed.
• the molar ratio of isocyanate groups of the polyurethane-based dispersion (calculated as isocyanate groups contained in the prepolymer of the organic phase (I)) and the sum of primary and secondary amino groups of the chain extension agent (calculated from the concentration of the respective agent in the aqueous composition) is greater than 0.8:1, for example from 0.8:1 to 3:1 or 0.9:1 to 2:1.
• the continuous mass flow of the polyurethane-based dispersion being discharged from the high shear dispersion device and the continuous mass flow of the composition comprising the chain extension agent are adjusted in a way that the molar ratio of isocyanate groups of the polyurethane-based dispersion (calculated as isocyanate groups contained in the prepolymer of the organic phase (I)) and the sum of primary and secondary amino groups of the chain extension agent (calculated from the concentration of the respective agent in the aqueous composition) is greater than 0.8:1, for example from 0.8:1 to 3:1 or 0.9:1 to 2:1.
• the fact that the chain extension agent is only added after the dispersion has left the high shear dispersion device has the advantage that effective crosslinking triggered by the chain extension agent does not occur within the device and thus avoids potential clogging and blocking processes of the intricate cavity system of the device.
• the duration between the point in time at which the dispersion is leaving the high shear dispersion device and the point in time of feeding / adding the chain extension agent is not more than 30 seconds.
• the residence time is not more than 20 seconds or even not more than 10 seconds or 5 seconds.
• Calculation of the residence time may be conducted under consideration of the mass flow of the aqueous polyurethane-based dispersion continuously discharged from the rotor/stator unit (and thus high shear dispersion device) and the volume which the polyurethane-based dispersion has to pass via the respective pipe system before the chain extending agent is fed/added (volume calculated, for example, via inner diameter of the pipe system and distance between the point where the aqueous polyurethane-based dispersion leaves the high shear dispersion device and the point where the chain extender agent is added).
• the calculation may be conducted via the parameters mass flow, inner diameter of the pipe system, length of relevant pipe system (exit from high shear dispersion device and the point where the chain extender agent is added) and density of the aqueous dispersion exiting the high shear dispersion device (for the calculation, the density at a temperature of 60°C was taken).
• the residence time is the average time which a part of the aqueous dispersion and thus polyurethane species is in contact with water, but without the chain extension agent.
• Step (6) of the process of the invention i.e. , feeding the chain extension agent and thus starting reaction of in particular amino groups of this chain extension agent with isocyanate, ultimately lead to production of an aqueous polyurethane-polyurea dispersion.
• the dispersion may be collected in a holding vessel, for example. It of course is also possible to directly convey the dispersion via pipe systems to further processes and respective plant setups, like processes and setups for producing coating materials.
• the dispersions preferably are microgel dispersions, i.e. polymer dispersions in which on the one hand the polymer is present in the form of comparatively small particles, or microparticles, and on the other hand the polymer particles are at least partly intramolecularly crosslinked.
• microgel dispersions have great advantages on versatile properties of coating materials like, for example, automotive coating compositions like pigmented automotive coating compositions. Such properties are, for example, excellent optical and mechanical properties of cured coatings prepared by such coating materials, on the one hand, and a high solids content and good storage stability of aqueous coating materials, in particular pigmented coating materials like basecoat materials, on the other.
• the fraction of the polyurethane-polyurea polymer in the aqueous dispersion is preferably 25 to 55 wt%, preferably 30 to 50 wt%, more preferably 35 to 45 wt%, based in each case on the total amount of the aqueous dispersion. Therefore, the solids content of the aqueous dispersion, quite obviously, preferably, is 25 to 55 %, preferably 30 to 50 %, more preferably 35 to 45 %.
• the fraction of water in the dispersion is preferably 40 to 70 wt%, preferably 45 to 65 wt%, more preferably 50 to 60 wt%, based in each case on the total amount of the dispersion.
• the aqueous dispersion consists preferably to an extent of at least 90 wt% of the polyurethane- polyurea polymer and water (calculated as sum of fraction of water and solids content of the dispersion (in wt%)).
• the content of organic solvents in the aqueous dispersion may be very low and preferably is below 10 wt%, based on the total weight of the dispersion.
• this very low content of organic solvents may be achieved without any need of a final distillation process for removing such organic solvents.
• the process of the invention preferably does not include such a distillation step (even if, of course, this is not excluded). Also, in case that such a distillation step is conducted, during this step normally only a minor fraction of organic solvent needs to be removed, quite obviously. Therefore, in case a distillation step is conducted, this step is comparably low energy and/or time consuming compared to what is known from the prior art.
• the process of the invention thus does not include a distillation step or the process of the invention includes a distillation step in which organic solvents are distilled of making up not more than a fraction of 5 wt% of the aqueous dispersion before distillation, whereby the process still results in an aqueous polyurethane-polyurea dispersion having a content of organic solvents of below 10 wt%.
• solids content also referred to as solid fraction hereinafter, was determined in accordance with DIN EN ISO 3251 at 130°C; 60 min, initial mass 1.0 g. If reference is made in the context of the present invention to an official standard, this of course means the version of the standard that was current on the filing date, or, if no current version exists at that date, then the last current version.
• the isocyanate content also referred to below as NCO content
• NCO content was determined by adding an excess of a 2% strength N,N-dibutylamine solution in xylene to a homogeneous solution of the samples in acetone/N-ethylpyrrolidone (1 :1 vol%), by potentiometric back-titration of the amine excess with 0.1 N hydrochloric acid, in a method based on DIN EN ISO 3251, DIN EN ISO 11909, and DIN EN ISO 14896.
• the NCO content of the polymer, based on solids, can be calculated back via the fraction of a polymer (solids content) in solution.
• the hydroxyl number was determined on the basis of R.-P. Kruger, R. Gnauck and R. Algeier, Plaste und Kautschuk, 20, 274 (1982), by means of acetic anhydride in the presence of 4- dimethylaminopyridine as a catalyst in a tetrahydrofuran (THF)/dimethylformamide (DMF) solution at room temperature, by fully hydrolyzing the excess of acetic anthydride remaining after acetylation and conducting a potentiometric back-titration of the acetic acid with alcoholic potassium hydroxide solution. Acetylation times of 60 minutes were sufficient in all cases to guarantee complete conversion.
• the MEQ base (in meq/g solids content) was determined on the basis of DIN EN ISO 15880 in homogeneous solution of tetrahydrofuran (THF)Zwater (9 parts by volume of THF and 1 part by volume of distilled water) by neutralization with hydrochloric acid.
• degree of neutralization The degree of neutralization of a component was calculated from the amount of substance of the carboxylic acid groups present in the component (determined via the acid number) and the amount of neutralizing groups (i.e. base) of the neutralizing agent used. The degree of neutralization can also be calculated as
• the amount of an organic solvent in a mixture was determined by means of gas chromatography (Agilent 7890A, 50 m silica capillary column with polyethylene glycol phase or 50 m silica capillary column with polydimethylsiloxane phase, helium carrier gas, 250°C split injector, 40 - 220°C oven temperature, flame ionization detector, 275°C detector temperature, n-propyl glycol as internal standard).
• M n The number-average molar mass (M n ) was determined, unless otherwise indicated, by means of a vapor pressure osmometer (VPO) 10.00 (from Knauer) on concentration series in toluene at 50°C with benzophenone as calibration substance for the determination of the experimental calibration constant of the instrument used, by the method of E. Schroder, G. Muller, K. F. Arndt, "Leitfaden der Polymer charactermaschine” [Principles of polymer characterization], Akademie-Verlag, Berlin, pp. 47 - 54, 1982.
• VPO vapor pressure osmometer
• the particle size was determined by laser diffraction or photon correlation spectroscopy (PCS).
• PCS photon correlation spectroscopy
• the defining parameter for describing the particle size according to the present invention is the volume-based mean diameter (also called “D[4.3] I De Broucker mean” in the context of laser diffraction). For the sake of completeness, also further parameters were determined (cf. below).
• a Malvern Nano S90 (from Malvern Instruments) at 25 ⁇ 1°C.
• the instrument is equipped with a 4 mW He-Ne laser at 633 nm.
• the samples i.e. aqueous dispersions
• the samples were diluted with particle-free, deionized water as dispersing medium, before being subjected to measurement in a 1 ml polystyrene cell at suitable scattering intensity.
• Evaluation took place using a digital correlator, with the assistance of the Zetasizer analysis software, version 6.32 (from Malvern Instruments). Measurement took place five times, and the measurements were repeated on a second, freshly prepared sample. The standard deviation of a 5-fold determination was 4%.
• the maximum deviation of the volume-based mean diameters of five individual measurements was ⁇ 15%.
• the reported particle size is the arithmetic mean of the volume-based mean diameters measured for the individual preparations. Verification was carried out using polystyrene standards having certified particle sizes between 50 to 3000 nm.
• gel fraction The gel fraction of the polyurethane-polyurea particles (microgel particles) present in the aqueous dispersions is determined gravimetrically in the context of the present invention.
• the polymer present was isolated from a sample of an aqueous dispersion (initial mass 1.0 g) by freeze-drying. Following determination of the solidification temperature - the temperature after which the electrical resistance of the sample shows no further change when the temperature is lowered further - the fully frozen sample underwent its main drying, customarily in the drying vacuum pressure range between 5 mbar and 0.05 mbar, at a drying temperature lower by 10°C than the solidification temperature.
• the insoluble fraction of the isolated polymer (gel fraction) was then separated off on a suitable frit, dried in a forced air oven at 50°C for 4 hours, and subsequently reweighed.
• gel fraction determined in this way in accordance with the invention is also called gel fraction (freeze-dried).
• a gel fraction hereinafter also called gel fraction (130°C) was determined gravimetrically, by isolating a polymer sample from aqueous dispersion (initial mass 1.0 g) at 130°C for 60 minutes (solids content). The mass of the polymer was ascertained, after which the polymer was extracted in an excess of tetrahydrofuran at 25°C, in analogy to the procedure described above, for 24 hours, after which the insoluble fraction (gel fraction) was separated off, dried, and reweighed.
• Example P1 Preparation of a polyurethane prepolymer (a) and an organic phase (I)
• a reaction vessel equipped with stirrer, internal thermometer, reflux condenser, and electrical heating 6110.6 parts by weight of a linear polyester polyol and 289.9 parts by weight of dimethylolpropionic acid (from GEO Speciality Chemicals) were dissolved under nitrogen in 650.0 parts by weight of methylisobutylketone (from BASF SE) and 650.0 parts by weight of dipropylenglycol dimethylether (Proglyme®, from BASF SE).
• the polyurethane prepolymer and the respective organic phase (I) was kept at 82 °C under nitrogen and was further processed within 12 hours. Within this time the isocyanate level and the viscosity remained constant.
• Solids content (130°C, 60min, 1g): 87.1 wt.-%
• GC Dipropylene glycol dimethylether content
• VPO Number average molecular weight
• TMXDI® tetramethylxylene diisocyanate
• Allnex tetramethylxylene diisocyanate
• isocyanate content 34.4 wt-%
• dibutyltin dilaurate from Merck
• the polyurethane prepolymer kept at 85 °C under nitrogen and was immediately processed to dispersion. Within 8 hours the isocyanate level and the viscosity remained constant.
• the characteristics of the prepolymer i.e. the organic phase (I) were as follows:
• VPO Number average molecular weight
• the organic phase (I) P1 was loaded into an addition tank at 82 °C under 5.0 bar nitrogen overpressure and was then fed continuously at a mass flow of 7.600 kg per hour through a stainless-steel pipe into a high shear dispersion device comprising a rotor/stator unit via a gear pump.
• the transfer tube was insulated and heated to 82°C.
• an aqueous phase (II) consisting of a 2.028 wt.-% triethylamine solution in deionized water was provided at 5°C and continuously fed through a separate pipe with a mass flow of 8.341 kg per hour into said high shear dispersion device comprising a rotor/stator unit by using an eccentric screw pump.
• the high shear dispersion device was based on a Cavitron CD 1010 rotor / stator dispenser from Hagen & Funke.
• the cylindrical stator subunit with centric inlet (13) further had 24 drill holes with an inner diameter of 2 mm (i.e. multiple inlets (14)) arranged in form of a circle and having uniform distances to each other.
• the stator subunit was equipped with three stator sets of teeth (11) (inner diameters: I - 35.2 mm, II - 52.5 mm, III - 63.5 mm) having different numbers of teeth (12) (I - 24, II - 34, III - 160), whereby the drill holes were positioned between two stator sets of teeth as shown in Figure 1 (i.e.
• the cylindric rotor subunit was equipped with four rotor sets of teeth (21) having a different number of teeth (22) (I - 12, II - 28, III - 70, IV - 160).
• the rotor sets of teeth were positioned alternatingly to the stator sets of teeth as in principle shown in Figure 3 and were rotatable at a maximum rotation speed of 12000 rpm.
• the high viscous organic-based phase (I) and low viscous aqueous phase were intensively dispersed under high shear.
• the resulting dispersion was discharged from an outlet located beyond the outmost rotor set of teeth.
• the rotor/stator unit was completely jacketed and internally cooled, leading to a temperature of said discharging dispersion of approximately 60°C.
• Chain extension was accomplished via a T joint injector.
• the aqueous dispersion discharged from the high shear dispersion device was continuously passed through a respective pipe system connected to one arm of a T joint, while the chain extension agent was continuously fed via a second arm of the T joint.
• the chain extension agent was continuously fed as an aqueous solution (8.0 wt.-% of diethylene triamine in deionized water) with a mass flow of 0.962 kg per hour by using a double piston pump (again for a duration of 23 minutes and 41 seconds, meaning that a total of 379.7 g of aqueous amine solution was supplied).
• a static mixer has been used for effectively mixing the polyurethan dispersion with the chain extension amine.
• the mass flows of the aqueous dispersion discharged from the high shear dispersion device and the diethylene triamine solution ensured a molar ratio of isocyanate groups of the polyurethane- based dispersion (calculated as isocyanate groups contained in the prepolymer of the organic phase (I)) and the sum of primary and secondary amino groups of the chain extension agent (calculated from the concentration of the respective diethylene triamine in the aqueous solution) of 1.62:1.
• the duration between the point in time at which the aqueous dispersion was leaving the high shear dispersion device and the point in time of feeding / adding the chain extension agent (residence time) was calculated to 6.8 s.
• the continuously produced aqueous polyurethane-polyurea dispersion was collected in a collecting vessel and cooled down to 23°C.
• a white, stable, solids-rich, low-viscosity dispersion containing crosslinked particles was obtained, and showed no sedimentation within 6 months.
• Solids content (130°C, 60min, 1g): 40.1 wt.-%
• aqueous polyurethane-polyurea dispersion D2 For preparation of aqueous polyurethane-polyurea dispersion D2 the same general procedure as for Example D1 were applied. However, instead of supplying the two streams of the organicbased phase (I) and aqueous phase (II) separately into the high shear dispersion device, the phases were combined via a T joint before entering the device. The combined fed stream then was fed into the rotor/stator unit via the centrically located first inlet (13). No drill holes (i.e multiple second inlets (14)) were existent.
• Solids content (130°C, 60min, 1g): 40.2 wt.-%
• aqueous polyurethane-polyurea dispersion D3 involves the same general procedure as for Example D1 except for applying solvent free organic phase (I) P2 (instead of P1). Therefore, different from example D2, the overall process conditions and in particular properties of the high shear dispersion device (drill holes etc.) were chosen as in example D1.
• the organic phase (I) P2 was loaded into an addition tank at 85 °C under 6.0 bar nitrogen overpressure and was then fed continuously at a mass flow of 6.498 kg per hour through a stainless-steel pipe into a high shear dispersion device comprising a rotor/stator unit via a gear pump.
• the transfer tube was insulated and heated (oil jacket) to 106°C, leading to a temperature of the organic phase when entering the high shear dispersion device of 90°C.
• an aqueous phase (II) consisting of a 1.807 wt.-% triethylamine solution in deionized water was provided at 5°C and continuously fed through a separate pipe with a mass flow of 9.266 kg per hour into said high shear dispersion device comprising a rotor/stator unit by using an eccentric screw pump. Both dosages were stopped after 27 minutes and 42 seconds. By that time, 3000.0 g of organic phase (I) and 4277.7 g of aqueous phase (II) were supplied. During the entire process, the mass flows of the two phases as mentioned above ensured a degree of neutralization of 84 %. The two streams were supplied, combined and dispersed as described in example D1. For reducing the temperature of the discharging dispersion, the rotor/stator unit again was completely jacketed and internally cooled.
• chain extension was again accomplished via a T joint injector.
• the aqueous dispersion discharged from the high shear dispersion device was continuously passed through a respective pipe system connected to one arm of a T joint, while the chain extension agent was continuously fed via a second arm of the T joint.
• the chain extension agent was continuously fed as an aqueous solution (8.0 wt-% of diethylene triamine in deionized water) with a mass flow of 0.761 kg per hour by using a double piston pump (for a duration of 27 minutes and 42 seconds, meaning that a total of 351.2 g of aqueous amine solution was supplied).
• a static mixer has been used for effectively mixing the polyurethan dispersion with the chain extension amine.
• the molar ratio of isocyanate groups of the polyurethane-based dispersion (calculated as isocyanate groups contained in the prepolymer of the organic phase (I)) and the sum of primary and secondary amino groups of the chain extension agent (calculated from the concentration of the respective diethylene triamine in the aqueous solution) again was kept at 1.62:1.
• the duration between the point in time at which the aqueous dispersion was leaving the high shear dispersion device and the point in time of feeding I adding the chain extension agent (residence time) was calculated to 6.9 s.
• the continuously produced aqueous polyurethane-polyurea dispersion was collected in a collecting vessel and cooled down to 23°C. A white, stable, solids-rich, low-viscosity dispersion containing crosslinked particles was obtained, and showed no sedimentation within 2 months.
• the characteristics of the produced aqueous polyurethane-polyurea dispersion D3 were as follows:
• Solids content (130°C, 60min, 1g): 40.0 wt.-%
• example D2 For comparative purposes, the device described in example D2 was applied for producing a dispersion based on organic phase (I) P2. The process could not be realized in any stable manner, the experiment was stopped.
• Example D4 Preparation of an aqueous polyurethane-polyurea dispersion Like in example D3, the preparation of the aqueous polyurethane-polyurea dispersion D4 again involves the same overall general procedure as for Example D1 in terms of properties of the high shear dispersion device (drill holes etc.). Deviations in particular lie in the selection and addition of the neutralizing agent.
• the organic phase (I) P1 was loaded into an addition tank at 82 °C under 5.5 bar nitrogen overpressure and was then fed continuously at a mass flow of 7.671 kg per hour through a stainless-steel pipe into a high shear dispersion device comprising a rotor/stator unit via a gear pump.
• the transfer tube was insulated and heated to 82°C.
• an aqueous phase (II) consisting of a 0.639 wt.-% sodium hydroxide (Fa.
• chain extension was again accomplished via a T joint injector.
• the aqueous dispersion discharged from the high shear dispersion device was continuously passed through a respective pipe system connected to one arm of a T joint, while the chain extension agent was continuously fed via a second arm of the T joint.
• the chain extension agent was continuously fed as an aqueous solution (8.0 wt.-% of diethylene triamine in deionized water) with a mass flow of 0.971 kg per hour by using a double piston pump (for a duration of 23 minutes and 28 seconds, meaning that a total of 379.7 g of aqueous amine solution was supplied).
• a static mixer Downstream of the T joint, again a static mixer has been used for effectively mixing the polyurethan dispersion with the chain extension amine.
• the duration between the point in time at which the aqueous dispersion was leaving the high shear dispersion device and the point in time of feeding I adding the chain extension agent (residence time) was calculated to 6.7 s.
• the continuously produced aqueous polyurethane-polyurea dispersion was collected in a collecting vessel and cooled down to 23°C. 54.2 g of a 10 wt.-% sodium hydroxide solution in deionized water were added under stirring to result in a degree of neutralization of 82 % (second neutralization step). A white, stable, solids-rich, low-viscosity dispersion containing crosslinked particles was obtained, and showed no sedimentation within 12 months.
• Solids content (130°C, 60min, 1g): 40.2 wt-%
• the produced aqueous polyurethane-polyurea dispersions D1 to D4 were well suitable for applications in, for example, basecoat materials like automotive basecoat materials.

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• 2024
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