Urea urethanes

Abstract

Urea urethane, obtained or obtained by a process comprising or consisting of the following steps: (a) Providing a monohydroxyl compound of formula (I) R-OH (I) in the R n-alkyl or isoalkyl with 4 to 22 carbon atoms, cycloalkyl with 6 to 12 carbon atoms, aralkyl with 7 to 12 carbon atoms or a residue of formula C m H 2m+1 (OC n H 2n ) x - or C m H 2m+1 (OOC-C v H 2v ) x - is, and m represents an integer from 1 to 22, n represents an integer from 2 to 4, x represents an integer from 1 to 15 and v represents 4 or 5; (b) Providing a diisocyanate compound of formula (II) OCN-[A]-NCO (II) in which A stands for a linear or branched alkylene residue with 2 to 10 carbon atoms and / or a toluene residue; (c) Reacting the monohydroxyl compound and the diisocyanate compound to form a prepolymer; (d) Reacting the prepolymer with a diamine compound, wherein the diamine compound is selected from the group consisting of (d1) Connection (III) H2N-[B]-NH2 (III) where B represents a linear, branched and / or cyclic alkylene group with 2 to 12 carbon atoms; and / or (d2) Connection (IV) H2N-(CH2) a -Ph-(CH2) b NH2 (IV) in which a and b independently represent integers from 1 to 5 and Ph stands for a phenyl residue, wherein the aforementioned prepolymer and the aforementioned diamine are reacted in the presence of a surfactant and the surfactant is a sulfosuccinate.

Description

AREA OF INVENTION

[0001] The present invention is in the field of additives for varnishes and paints and relates to urea urethanes with improved rheological behavior and thixotropic agents containing them. TECHNOLOGICAL BACKGROUND

[0002] Organically modified bentonites, silicas, hydrogenated castor oil, and polyamide waxes are predominantly used to modify the rheology of liquid coatings. A disadvantage of these substances is that they are generally dry solids that must be dispersed into semi-finished products using solvents and shear forces, or incorporated into the liquid coating by controlled temperature control. If these temperatures are not maintained, crystallites form in the finished coating, which can lead to defects.

[0003] The general disadvantage of these currently used rheology aids is that they cause haze and clouding on clear, transparent coatings. Furthermore, handling dry, powdery products that generate dust during processing is undesirable. STATE OF THE ART

[0004] Further advances in the field of rheology control are disclosed in European patent application EP 0198519 B1 (AKZO). This application describes the reaction of an isocyanate with an amine in the presence of coating resin solutions to form a urea that creates needle-shaped crystals in a very finely dispersed form. These modified coating binders are offered as rheology control agents and deflection inhibitors, also known as "sag control agents." However, the disadvantage of these products is that they are always bound to the binder in which they were manufactured and do not allow for any subsequent universal correction of finished coating materials.

[0005] European patent EP 0006252 B1 (BYK CHEMIE) describes a process for the production of a thixotropic agent that eliminates some of the aforementioned disadvantages by describing urea-urethanes prepared in aprotic solvents in the presence of LiCl by reacting isocyanate adducts with polyamines. The disadvantage of the products prepared in this way is the undefined structure of the urea-urethanes due to the preparation method. Although isocyanate monoadducts are mentioned, in this case they are by no means monoadducts, as the example makes clear, but rather mixtures of different adducts. In the described process, one mole of a diisocyanate is initially reacted with one mole of a monoalcohol. This yields some of the desired NCO-functional monoadducts, but also some non-NCO-functional diadducts. Furthermore, a portion of the monomeric diisocyanate remains unreacted.

[0006] The proportions of these different compounds can vary depending on the accessibility of the NCO group and the reaction conditions used, such as temperature and time. However, the major disadvantage is that all adducts prepared in this way contain fairly large amounts of unreacted diisocyanate, which, upon further reaction with polyamines in the presence of lithium chloride, leads to uncontrolled chain elongation of the urea-urethane and to polymeric urea compounds. These products then tend to precipitate and can only be kept in solution with great difficulty.

[0007] A solution to this problem is offered by European patent EP 1048681 B1 (BYK CHEMIE), which proposes carrying out the reaction described above with a molar excess of the diisocyanate compound of at least 1.5, preferably of about 2 to 3 and up to 5. The unreacted diisocyanate is separated, for example, by vacuum distillation. TASK OF INVENTION

[0008] A significant disadvantage of the processes described above is that they require the presence of lithium salts as an initiator for the formation of urethanes. Once these urethanes are formulated into a ready-to-use additive, they also serve as stabilizers for customers' end products, such as paints and coatings. Despite these advantages, lithium salts remain controversial due to their high corrosiveness. Another drawback of lithium is that its reserves are limited and its production is generally environmentally damaging.

[0009] Therefore, the aim of the present invention was to find alternative stabilizers for the polyurethane reaction which simultaneously provide stability to the formulations and are non-corrosive or at least less corrosive, so that the presence of lithium salts, in particular lithium chloride or lithium nitrate, can be avoided during the manufacturing process.

[0010] A second object of the invention relates to the provision of thixotropic agents based on urea-urethanes which are either free of lithium or at least have a lower content compared to the products available on the market. DESCRIPTION OF THE INVENTION

[0011] A first object of the invention relates to urea urethanes obtainable or obtained by a process comprising or consisting of the following steps: (a) Providing a monohydroxyl compound of formula (I) R-OH (I) in the R n-alkyl or isoalkyl with 4 to 22 carbon atoms, cycloalkyl with 6 to 12 carbon atoms, aralkyl with 7 to 12 carbon atoms or a residue of formula C m H 2m+1 (OC n H 2n ) x - or C m H 2m+1 (OOC-C v H 2v ) x - is, and m represents an integer from 1 to 22, n represents an integer from 2 to 4, x represents an integer from 1 to 15 and v represents 4 or 5; (b) Providing a diisocyanate compound of formula (II) OCN-[A]-NCO (II) in which A stands for a linear or branched alkylene residue with 2 to 10 carbon atoms and / or a toluene residue; (c) Reaction of the monohydroxyl compound and the diisocyanate compound to form a prepolymer; (d) reacting the prepolymer with a diamine compound, wherein the diamine compound is selected from the group consisting of (d1) Connection (III) H2N-[B]-NH2 (III) where B represents a linear, branched and / or cyclic alkylene group with 2 to 12 carbon atoms; and / or (d2) Connection (IV) H2N-(CH2) a -Ph-(CH2) b NH2 (IV) in which a and b independently represent integers from 1 to 5 and Ph stands for a phenyl residue, in which the mentioned prepolymer and the mentioned diamine are reacted in the presence of a surfactant and the surfactant is a sulfosuccinate.

[0012] The reaction can be carried out in the presence of an aprotic solvent; however, the solvent can also be added after the reaction of the prepolymer with the diamine.

[0013] Surprisingly, it has been observed that the formation of polyurethanes from isocyanates and amines occurs rapidly and in high yields when sulfosuccinate-type surfactants are present. Customer products containing the urea urethanes of the present invention, or rheological additives containing them, exhibit stability that is at least comparable to, and in many cases even better than, that of commercially available products containing similar amounts of lithium salts. Therefore, sulfosuccinates have not only proven to be complete replacements for lithium salts, but also offer the additional advantage of being non-corrosive. Manufacturing process

[0014] The process for producing the urea urethanes according to the invention, which comprises or consists of the following steps, is not subject to the claimed scope of protection: (a) Providing a monohydroxyl compound of formula (I) R-OH (I) in the R n-alkyl or isoalkyl with 4 to 22 carbon atoms, cycloalkyl with 6 to 12 carbon atoms, aralkyl with 7 to 12 carbon atoms or a residue of formula C m H 2m+1 (OC n H 2n ) x - or C m H 2m+1 (OOC-C v H 2v ) x - is, and m for an integer from 1 to 22, n represents an integer from 2 to 4, x represents an integer from 1 to 15 and v represents 4 or 5; (b) Providing a diisocyanate compound of formula (II) OCN-[A]-NCO (II) in which A stands for a linear or branched alkylene residue with 2 to 10 carbon atoms and / or a toluene residue; (c) Reaction of the monohydroxyl compound and the diisocyanate compound to form a prepolymer; (d) reacting the prepolymer with a diamine compound, wherein the diamine compound is selected from the group consisting of (d1) Connection (III) H2N-[B]-NH2 (III) where B represents a linear, branched and / or cyclic alkylene group with 2 to 12 carbon atoms; and / or (d2) Connection (IV) H2N-(CH2) a -Ph-(CH2) b NH2 (IV) in which a and b independently represent integers from 1 to 5 and Ph stands for a phenyl residue, wherein the aforementioned prepolymer and the aforementioned diamine are reacted in the presence of a surfactant and the surfactant is a sulfosuccinate.

[0015] As mentioned, the reaction can be carried out in the presence of an aprotic solvent; however, the solvent can also be added after the reaction of the prepolymer with the diamine. Monohydroxyl compounds

[0016] Suitable monohydroxyl compounds include linear or branched, aliphatic or aromatic alcohols with 4 to 22, preferably 6 to 12 carbon atoms, and their alkylene oxide adducts, preferably adducts averaging 1 to 20, preferably 2 to 10 moles of ethylene oxide, propylene oxide, or mixtures thereof, to one of the aforementioned alcohols. Particularly preferred are butanol (all isomers), pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, myristyl alcohol, stearyl alcohol, cetyl alcohol, oleyl alcohol, erucyl alcohol, behenyl alcohol, phenol, benzyl alcohol, and their technical-grade mixtures and adducts of 1 to 20, preferably 2 to 10 moles of ethylene oxide and / or 1 to 5, preferably 2 to 4 moles of propylene oxide.

[0017] Particularly preferred, however, are alkyl polyalkylene glycol ethers, preferably alkyl polyethylene glycol ethers with a molecular weight of about 200 to about 1,000 Daltons, such as methyl ether (MPEG) or butyl ether (BPEG) of PEG100, PEG200, PEG300, PEG350 or PEG500. Diisocyanate compounds

[0018] While the diisocyanate compound may be of aliphatic origin, preferred embodiments include aromatic or cycloaliphatic compounds or mixtures thereof, such as: - Methylene diphenyl isocyanate (MDI) - Toluene diisocyanate (TDI) - Xylylene diisocyanate (XDI) - Hexamethylene diisocyanate (HDI) - Isophorone diisocyanate (IPDI) - 4,4-Dicyclohexylmethane diisocyanate (H12MDI)

[0019] Toluene diisocyanate (also called toluene diisocyanate) is particularly preferred. With regard to the performance of the final product, a toluene diisocyanate containing approximately 50 to approximately 80 mol% of the 2,4-isomer is particularly preferred. Diamine compounds

[0020] Suitable diamine compounds are aliphatic, cycloaliphatic, and aromatic diamines. A suitable diamine is, for example, where R''' represents hydrogen or a methyl group. However, the preferred species is xylenediamine.

[0021] In a particularly preferred embodiment, the urea urethanes of the present invention are obtained by reacting MPEG300, MPEG350, BPEG300 or BPEG350 with toluene diisocyanate in a molar ratio of 1:1.05 to 1:1.6 to form a prepolymer, which is subsequently reacted with xylenediamine to form the final product and is represented by the following formula: Reaction step 1: Formation of the prepolymer

[0022] Crucial to the present invention is the formation of the prepolymer in which the monohydroxyl compounds and the diisocyanate compounds are reacted in a molar ratio of about 1:1.05 to about 1:6, preferably of about 1:1.05 to about 1:3 and even more preferably of about 1:1.1 to about 1:2.5.

[0023] Depending on the excess of diisocyanate, prepolymers containing one or two polyether groups are obtained. A disubstituted prepolymer does not offer a free reaction site for condensation with the amine group and remains as such in the final composition. However, the applicant recognized that the unsatisfactory performance of similar products on the market is related to the amount of unreacted prepolymers. By reducing the excess of diisocyanate, the amount of prepolymers available for further condensation with the diamine compound—as desired—is significantly increased. This leads not only to products with improved performance but also to a composition that differs from market products and is therefore novel compared to the prior art.

[0024] After the formation of the prepolymer, it is advantageous to remove the unreacted diisocyanate, e.g., by vacuum distillation. Preferably, the remaining prepolymers have an unreacted diisocyanate content of less than 0.5 wt.%, preferably of about 0.1 to 0.2 wt.%.

[0025] The specific reaction conditions are illustrated by the production examples, but are not limited to these. Reaction step 2: Formation of urea urethane

[0026] The resulting prepolymer is then reacted with a diamine compound, preferably in at least one solvent, preferably an aprotic solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, or N-butylpyrrolidone, or similar alkylpyrrolidones. Typically, the diamine compound—and optionally the lithium salt—is dissolved in the solvent and added to the reactor, to which the prepolymer is added. The preferred solvent is N-methylpyrrolidone, as it is not currently classified as a CMR (carcinogenic, mutagenic, or reprotoxic).

[0027] The molar ratio between prepolymer and diamine compound is adjusted to approximately 1:1.2 to 1.2:1, preferably to approximately 1:1.1 to 1.1:1.

[0028] The amount of solids can be adjusted within a wide range from about 5 to about 80 wt.%, preferably about 20 to about 60 wt.%, and particularly preferably about 40 to about 50 wt.%. The proportion to 100% is the solvent, which optionally contains small amounts of suitable additives such as corrosion inhibitors.

[0029] The urea urethanes produced according to the invention contain neither free isocyanate groups nor free amino groups. They are therefore physiologically harmless. Furthermore, no undesirable side reactions occur with binders or fillers. The storage stability of these urea urethane solutions produced in this way is exceptionally high and can easily reach 6 months or more at normal storage temperature. Sulfosuccinate

[0030] The core of the invention consists in carrying out urethane formation in the presence of a specific type of surfactant, namely sulfosuccinates, instead of lithium salts. Sulfosuccinic acid esters are sulfonation products of succinic acid mono- and diesters with the general formula R 1 OOC-CH2-CH(SO3X)-COOR2

[0031] with R 1 = H, C1-C 18 -Alkyl, R 2 = C1-C 18 -Alkyl and X = alkali, alkaline earth, ammonium, or alkylammonium. The preferred sulfosuccinates are mono- or diesters of linear or branched alcohols with 6 to 12, and preferably 8, atoms, such as octanol or 2-ethylhexyl alcohol. The structures may also contain polyalkylene glycol groups, such as 1 to 10 moles of ethylene oxide and / or propylene oxide. These structures (also called ether sulfosuccinates) are derived from the corresponding adducts of alkylene oxides to alcohols.

[0032] The amount of surfactant is approximately 0.2 to approximately 2 mol, preferably approximately 0.5 to approximately 1.5 mol, particularly preferably approximately 0.75 to approximately 1.25 mol of surfactant, based on the amine equivalent of the diamine used. COMMERCIAL APPLICABILITY

[0033] A further aspect of the present invention is a thixotropic agent comprising the novel urea urethanes as described above and a solvent. The preferred solvents are aprotic and include, for example, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, or N-butylpyrrolidone, or similar alkylpyrrolidones. Typically, the solvent is present in an amount of about 20 to about 95 wt.%, preferably about 40 to about 80 wt.%, and even more preferably about 50 to about 60 wt.%.

[0034] The thixotropic agents may also contain small amounts of lithium salts, particularly lithium chloride and / or lithium nitrate, which are added to the formulation but are not present during the formation of the urethanes. These amounts may range from about 0.1 to about 2 wt%, preferably from about 0.5 to about 1 wt%. These amounts can be helpful in further improving the viscosity stability in a paint or solution. EXAMPLES GENERAL MANUFACTURING PROCESS Synthesis of monoisocyanate with glycol compounds

[0035] A 1-liter reactor was charged with diisocyanate and placed under a nitrogen blanket at 25 °C. The glycol compound was added dropwise to the mixture with stirring. The temperature was not raised above 35 °C. After the addition was complete, the reaction was monitored for the NCO content and stopped when the NCO content reached a value corresponding to the theoretical amount for a monoadduct. Subsequently, the excess diisocyanate was evaporated under vacuum at 150 to 175 °C. A light brown product was obtained. The final NCO content was less than 7%, and the product had a viscosity of approximately 400 to 500 mPas (measured at 25 °C). The final free diisocyanate content was less than 0.1%. Synthesis of polyurea based on monoisocyanate from Example 1A

[0036] The reactor was loaded with surfactant, approximately 220 g of n-butylpyrrolidone (NBP), and 4.5 wt% m-xylenediamine, calculated based on the NCO content. The mixtures were heated to 95°C with stirring. After the surfactant was completely dissolved, a homogeneous mixture of approximately 180 g of monoadduct from Example A and 72.50 g of NBP was added over about 1 hour. The reaction mixture was stirred for about 50 minutes and cooled to room temperature as soon as no NCO signal was visible on IR. Clear, low-viscosity products were obtained.

[0037] The following Tables 1 and 2 contain the parameters for the various embodiments and the components used to produce the polyurethanes: Table 1 Reaction conditions parameter 1 2 3 4 5 A Isocyanate type A1 A1 A1 A1 A2 Quantity [g] 209 261 348 870 375 Amount [mol] 1.2 1.5 2.0 3.0 1.5 B Glycol component type B1 B1 B1 B1 B1 Quantity [g] 382 382 382 382 382 Amount [mol] 1.0 1.0 1.0 1.0 1.0 C surfactant type C1 C1 C1 C1 C1 Quantity [wt.%]* 1.2 1.4 1.4 1.5 1.2 *) Amount calculated based on the amine equivalent of the diamine used Table 2 Materials A1 Toluene diisocyanate (80% 2.4 isomer) Desmodur T80 A2 Diphenylmethane diisocyanate Desmodur MDI B1 Polyethylene glycol monobutyl ether (MW: 382) BPEG B2 Polyethylene glycol monomethyl ether (MW: 350) MPEG C1 Dioctyl sulfosuccinate sodium salt APPLICATION EXAMPLES

[0038] The product from manufacturing example 1 was compared with a market product (C1) and a comparison product (C2) that was manufactured according to the following procedure:

[0039] A first 1-liter reactor was loaded with 209 g (1.2 mol) of toluene diisocyanate and placed under a nitrogen blanket at 25°C. 382 g (1.0 mol) of polyethylene glycol monobutyl ether were added dropwise to the mixture with stirring. The temperature was not raised above 35°C. After the addition was complete, the reaction was monitored for the NCO content and stopped when the NCO content reached a value corresponding to the theoretical amount for a monoadduct. Subsequently, the excess diisocyanate was evaporated under vacuum at 150 to 175°C. A light brown product was obtained. The final NCO content was less than 7%, and the product had a viscosity of approximately 400 to 500 mPas. The final content of free diisocyanate was less than 0.1%. A second 1-I reactor was charged with 1.2 wt% lithium chloride, 220 g n-butylpyrrolidone (NBP) and 22.5 g m-xylenediamine (4.5 wt% based on the NCO content).The mixture was heated to 95°C with stirring. Once the salt had completely dissolved, a homogeneous mixture of approximately 180 g of the mono-adduct from the above-mentioned product and 72.50 g of NBP was added over about 1 hour. The reaction mixture was stirred for about 50 minutes and cooled to room temperature once no NCO signal was visible on IR. A clear, low-viscosity product was observed.

[0040] All three products were added at 1.2% and 1.7% w / w to a standard xylene-based lacquer formulation and also to a butyl acetate lacquer formulation. Fig. The values ​​ / 4 to 3 / 4 provide information about the stability of the compositions in a tan δ diagram over time. The results show that the products according to the invention perform equally well compared to the reference products; in some cases, the stability is even better.

[0041] The figures show the tan Δ, which corresponds to G'' / G' (viscosity loss modulus / elasticity storage modulus). A tan Δ value below 1 means that the elastic modulus dominates and the material behaves like a solid. Values ​​above 1 mean that the material behaves like a (viscous) fluid. - The first section (0 - 120 sec.) of the diagram is used to measure the structure in the paint formulation after application. - The second section (120 - 240 sec., not visible in the diagram) of the diagram serves to destroy the entire structure in the color sample. - The third section (240–720 seconds) of the diagram is used to measure the recrosslinking of the paint sample after destruction. This section should recover to the same level as the first section as quickly as possible (at least < 1). The following values ​​are used: G'': Elastic storage modulus: The ability of the material to store energy. G': Viscosity loss modulus: The ability of the material to dissipate energy (energy is lost as heat).

[0042] The product according to the invention and the LiCI-containing comparator product were subjected to a solvent gel test. The results are listed in Table 3: Table 3 Solvent Gel Test Solvent tests (6% addition to the solvent) product % by weight Water Ethanol Ethyl acetate Butyl acetate Xylene Example Precipitations Strong yellow cloudiness Cloudy gel Cloudy gel Cloudy gel E1 1,2 White gel Strong yellow cloudiness Strong Gel Strong yellow cloudiness Strong Gel C2 1,2 Precipitations Strong yellow cloudiness Liquid, precipitates Partially gel-like Weak gel C2 1,7 Precipitations Strong gel white Fluid Fluid Fluid Method:

[0043] Six percent by weight of thickener (corrected for solids content) was added to the pure solvent. The rheology modifier was mixed by hand. A gel should form after two hours. The mixture was visually inspected by rotating the container. The thicker the gel, the better the performance in a clear solvent. The product according to the invention showed better gel performance than the LiCl-based comparison. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 0198519 B1

[0004] EP 0006252 B1

[0005] EP 1048681 B1

[0007]

Claims

[1] Urea urethane, obtained or obtained by a process comprising or consisting of the following steps: (a) Providing a monohydroxyl compound of formula (I) R-OH (I) in the R n-alkyl or isoalkyl with 4 to 22 carbon atoms, cycloalkyl with 6 to 12 carbon atoms, aralkyl with 7 to 12 carbon atoms or a residue of formula C m H 2m+1 (OC n H 2n ) x - or C m H 2m+1 (OOC-C v H 2v ) x - is, and m represents an integer from 1 to 22, n represents an integer from 2 to 4, x represents an integer from 1 to 15 and v represents 4 or 5; (b) Providing a diisocyanate compound of formula (II) OCN-[A]-NCO (II) in which A stands for a linear or branched alkylene residue with 2 to 10 carbon atoms and / or a toluene residue; (c) Reacting the monohydroxyl compound and the diisocyanate compound to form a prepolymer; (d) Reacting the prepolymer with a diamine compound, wherein the diamine compound is selected from the group consisting of (d1) Connection (III) H2N-[B]-NH2 (III) where B represents a linear, branched and / or cyclic alkylene group with 2 to 12 carbon atoms; and / or (d2) Connection (IV) H2N-(CH2) a -Ph-(CH2) b NH2 (IV) in which a and b independently represent integers from 1 to 5 and Ph stands for a phenyl residue, wherein the aforementioned prepolymer and the aforementioned diamine are reacted in the presence of a surfactant and the surfactant is a sulfosuccinate. [2] Urea urethane according to claim 1, characterized by, that the monohydroxyl compound is an alkyl polyalkylene glycol ether with a molecular weight of approximately 200 to approximately 1,000 Daltons. [3] Urea urethane according to claim 1 and / or 2, characterized by that the diisocyanate compound is toluene diisocyanate. [4] Urea urethane according to any one of claims 1 to 3, characterized by that the monohydroxyl compound and the diisocyanate compound are reacted in a molar ratio of 1:1.05 to 1:

6. [5] Urea urethane according to any one of claims 1 to 4, characterized by that the diamine compound is xyloldiamine. [6] Urea-urethane according to any one of claims 1 to 5, characterized by that the surfactant is a dioctyl sulfosuccinate or a 2-ethylhexyl sulfosuccinate. [7] Urea urethane according to any one of claims 1 to 6, characterized by that the surfactant is present in an amount of approximately 1.0 to approximately 2.0 wt%, calculated on the total reaction mixture. [8] Urea urethane according to any one of claims 1 to 7, characterized by that the prepolymer and the diamine compound are reacted in an aprotic solvent. [9] Thixotropic agent comprising the urea urethane according to claim 1 and a solvent. [10] The composition of claim 9, further comprising a lithium salt.

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