Abstract: An aqueous polyurethane resin dispersion containing a polyurethane resin obtained by reacting (A) a polyurethane prepolymer obtained by reacting (a) a polyisocyanate compound, (b) at least one polyol compound containing a polycarbonate polyol having a number average molecular weight of 400 to 3000, (c) an acidic group-containing polyol compound, and (d) a blocking agent for an isocyanate group, which dissociates at 80 to 180° C., and (B) a chain elongating agent having reactivity with the isocyanate group, being dispersed in an aqueous medium, a sum of a content of urethane bondings and a content of urea bondings is 7 to 18% by weight of solid components, a content of carbonate bondings is 15 to 40% by weight of solid components, and a content of an isocyanate group to which the above-mentioned blocking agent has bonded is 0.2 to 3% by weight of solid components and calculated on the isocyanate group.

Abstract: The invention relates to an electrode binder composition, an electrode made using the described binder composition, and an electrochemical cell made using the described electrode, where the all of these materials are made using a composition of a poly(dialkylene ester) thermoplastic polyurethane composition. The electrode is made using the described thermoplastic polyurethane and an electrode active material. The electrochemical cells can be made using the described electrodes and also using (i) membranes and/or separators made using the described poly(dialkylene ester) thermoplastic polyurethane composition; (ii) an electrolyte system based on the described poly(dialkylene ester) thermoplastic polyurethane composition; or (iii) a combination thereof.

Abstract: The composition is a composition for forming a thermally-cured coating film, and comprises polyurethane resin comprising at least one group selected from the group consisting of a methacryloyloxy group, an acryloyloxy group, a methacryloyl group, and an acryloyl group; polythiol; and solvent.

Abstract: The present invention relates to zinc(II) complex compounds of the formula Zn(L)x(Y)2-x, wherein the ligand L has the formula (I). Such complex compounds are particularly suitable as catalysts for two-component polyurethane compositions. The invention also relates to two-component polyurethane compositions including at least one polyisocyanate as a first component, at least one polyol as a second component and at least one such zinc(II) complex compound as a catalyst. In addition, the invention relates to various uses of these two-component polyurethane compositions.

Abstract: A compound for imparting water repellency and optionally stain release to substrates wherein the compound is prepared by (i) reacting (a) at least one isocyanate group-containing compound selected from isocyanate, diisocyanate, polyisocyanate, or mixture thereof, and (b) at least one isocyanate-reactive compound selected from formula (Ia), (Ib), or (Ic):

Abstract: The present disclosure provides novel aqueous pigment dispersions containing an aqueous vehicle, a pigment and a branched polyurethane as a dispersant. Also disclosed is the use of these dispersions in ink-jet inks.

Abstract: The present invention provides high solids, two-component polyurethane compositions comprising, as one component, polyisocyanate compositions having one or more isocyanurate made from bis(isocyanatomethyl)-cyclohexane, as a second component, one or more high solids polyol, and in either component, one or more tertiary amine catalyst. Optionally, the compositions further comprise one or more zinc amine catalyst. The compositions provide coatings, which exhibit an excellent balance of pot life and dry to touch or tack free time, as well as early rain resistance and hardness, while enabling a lower volatile organic content (VOC) of the compositions for comparable performance.

Abstract: Disclosed herein is a family of patient positioners that are formed as a reaction product of substantially plant based constituents. In particular, surgical grade foam positioners are configurable in a variety of anatomically acceptable forms are disclosed that are substantially odor free.

Abstract: A process for preparing a polymer comprising reacting at least the components i) to iii) in any order: i) a compound of the Formula (1): Formula (1) wherein: T1 and T2 independently are HO—, HS— or R1HN—; Q1 and Q2 independently are —NR2—; A1 and A2 independently are an optionally substituted divalent organic linking group; R1 when present is H or an optionally substituted alkyl, aryl or heterocyclyl group; R2 is H or an optionally substituted alkyl, aryl or heterocyclyl group; Z is an HO— group or a group of the Formula (2) or (3); Formula (2) wherein: L is —HN—, —O— or —S—; X is an optionally substituted organic group; Formula (3) wherein: each X independently is an optionally substituted organic group; in both Formulae (2) and (3) the asterisk (*) signifies the point of attachment to the triazine ring: ii) a diisocyanate; iii) an isocyanate reactive compound having at least one ionic group.

Abstract: Primer compositions for adhering two sheets of polymer material to one another are provided. The primer compositions include polyurethanes that are the reaction product of an isocyanate, and at least one of a polyol, a chain extender, and a diamine. The polyurethanes may include pure polyurethanes, or commercially available varieties that may include other additives. The premier compositions are well-suited for adhering polycarbonate and polyurethane sheets together for use in transparent armor applications, as they help to ensure a very strong bond between the two sheets, and resist delamination.

Abstract: An embodiment relates to a redispersible polymer powder (RDP) composition for use in the preparation of dry mortar formulations, especially of cementitious bound tile adhesives (CBTA) and adhesives for external thermal insulation composite systems (ETICS). An embodiment further relates to a dry mortar formulation comprising said RDP composition. Embodiments relate to the composition and manufacture of water-redispersible polymer powders that comprise polyurethane powders, particularly where said polyurethane powders comprise particles of ground polyurethane foam. An embodiment is further directed to a method of improving adhesion of said polyurethane powder particles to mineral components of a dry mortar formulation. Furthermore, an embodiment is directed to a method of improving impact resistance of a cured dry mortar formulation without deteriorating workability of the wet mortar or the adhesion strength of the cured dry mortar formulation.

Abstract: The invention relates to an isocyanate-terminated polysiloxane material that can preferably be used as a curing agent, hardener or co-reactant in coatings. The invention further relates to a method of manufacturing the isocyanate-terminated polysiloxane material by partially hydrolyzing a methoxy-functional polysiloxane such as a methyl phenyl polysiloxane, and reacting it with a polyisocyanate to yield the isocyanate-terminated polysiloxane hardener. The hardener can preferably be used with any isocyanate-reactive functional group of another component to form coating systems, including acrylics, polyesters, epoxies and urethanes.

Abstract: A process for the preparation of a dispersion, comprising: dispersing a composition comprising a particulate solid, a liquid medium and a dispersant; wherein the dispersant is obtained by a process comprising at least the steps a) and b): a) co-polymerising a monomer composition comprising at least the components i) and ii) so as to form a phospho-ester functional polymer: i) a monomer having at least one phospho-ester group and two groups independently selected from hydroxyl, amino, thiol and hydrazo groups, ii) a diisocyanate; and b) hydrolysing at least some of the phospho-ester groups in the phospho-ester functional polymer so as to result in a dispersant having phosphorus containing anionic groups.

Abstract: A composition having a polyurea made by reacting a polyisocyanate with one of the below compounds. The value x is 2 or 3. A method of: providing a polyisocyanate and one of the below compounds, spraying the polyisocyanate and the compound with a plural component pump onto a surface to form a mixture, and allowing the mixture to cure to a polyurea.

Abstract: Hard coating compositions are disclosed containing graphenic carbon particles. The coating compositions include polymeric resins such as polyurethane or polyester with relatively small amounts of graphenic carbon particles that provide increased hardness.

Abstract: The present invention provides polyurethanes including a reaction product of components including: (a) an isocyanate functional urethane prepolymer comprising a reaction product of components including: (i) about 1 equivalent of at least one polyisocyanate; and (ii) about 0.1 to about 0.5 equivalents of at least one diol having 2 to 18 carbon atoms; and (b) about 0.05 to about 0.9 equivalents of at least one branched polyol having 4 to 18 carbon atoms and at least 3 hydroxyl groups; and (c) up to about 0.9 equivalents of at least one polyol different from branched polyol (b) and having 2 to 18 carbon atoms, wherein the reaction product components are essentially free of polyester polyol and polyether polyol; compositions, coatings and articles made therefrom and methods of making the same.

Abstract: An ink composition for inkjet recording including: a urethane oligomer or polymer that has at least one group selected from the group consisting of groups represented by following Formulae (1) to (3) at one or more side chains of the oligomer or polymer; and an organic solvent.

Abstract: Polymerizable liquid compositions of the polyurethane type, consisting of two components (A) and (B), wherein component (A) contains at least one cyclo-aliphatic diisocyanate monomer or a mixture of one cyclo-aliphatic diisocyanate monomer and a pre-polymer obtained by reaction, in the presence of an acid phosphate ester catalyst, between said cyclo-aliphatic diisocyanate monomer and one or more polyols having two or more hydroxy 1 groups per molecule and a molecular weight ranging from 50 to 2,000 g/mole; the second component (B) contains one or more polyols having a molecular weight ranging from 50 to 2,000 g/mole and a functionality between 2 and 5; in the absence of polyalkoxylated tertiary diamines and organometallic catalysts, said components (A) and (B) being present in a weight ratio which varies from 1:1 to 2:1 and the process for the production of organic glass starting from polymerizable liquid compositions of the polyurethane type.

Abstract: A composite material includes: carbon fibers having an average fiber length of more than about 10 mm and about 100 mm or less; and a thermoplastic resin. The carbon fibers are substantially two-dimensionally-randomly oriented. The composite material includes a carbon fiber bundle (A) in a ratio of more than 0 volume % and less than about 30 volume % to a total volume of the carbon fibers, the carbon fiber bundle (A) including the carbon fibers of a critical single fiber number defined by formula (1) or more. An average number (N) of the carbon fibers in the carbon fiber bundle (A) satisfies formula (2). Critical single fiber number=600/D??(1) 1.0×104/D2<N<2.5×104/D2??(2) D is an average fiber diameter (?m) of the carbon fibers.

Abstract: The present invention relates to a molding composition, a process for the manufacturing of said molding composition, molded parts obtainable therefrom as well as the use of the molding composition for the manufacturing of molded parts used in the automotive industry, for housings, latches, window winding systems, wiper systems, sun roof systems, seat adjustments, levers, gears, claws, pivot housing or wiper arms.

Abstract: The present invention relates to processes for preparing compact transparent polyurethanes by mixing (a) isocyanates with (b) compounds having at least two isocyanate-reactive groups, (c) catalysts, and optionally (d) auxiliaries and additives to give a reaction mixture and carrying out reaction to the compact transparent polyurethanes, the isocyanates (a) comprising at least 50 wt % of biurets of hexamethylene diisocyanate. The present invention further relates to a compact, transparent polyurethane prepared by a process of the invention, and to the use of such a compact, transparent polyurethane as a surface coating, more particularly in the interior of means of transport.

Abstract: Coating compositions comprising a polyurea formed from a reaction mixture comprising: (a) a first component comprising an isocyanate, the first component having a viscosity of ?2000 centipoise at a temperature ?7° C.; and (b) a second component comprising an amine. Substrates coated at least in part with such a composition are also disclosed. Footwear coated at least in part with polyurea are also disclosed.

Abstract: Isocyanurate-reactive mixture obtained by reacting an anhydride and a polyol; process for making it; polyisocyanate composition comprising this mixture; binder composition comprising such a polyisocyanate composition; the use of such a polyisocyanate composition and/or binder composition for making a polyisocyanurate and such polyisocyanurates.

Abstract: The invention is directed to coating compositions comprising A) at least one hydroxyl-functional and optionally acid-functional binder, preferably with an acid number of 0 to 150 mg KOH/g binder solids, B) at least one polyisocyanate curing agent with free isocyanate groups, C) at least one thermally latent tetrahydrocarbyl tin catalyst of general formula (I) RnR?4-nSn??(I) wherein R is an alkyl group, R? is an aryl, arylalkyl or alkenyl group and n is 1, 2 or 3, and D) optionally at least one acid-functional compound, that is different from component A), with the proviso that the acid number of a composition, consisting of the at least one binder A) and optionally of the at least one acid-functional compound D), has an acid number of at least 5 mg KOH/g solids, preferably of least 10 mg KOH/g solids, and to a process for coating substrates comprising the steps: I) applying the coating composition to an optionally pre-coated substrate, and II) curing the applied coating composition by means of thermal ene

Abstract: Provided is a surface protective film including, as an outermost layer, a pressure-sensitive adhesive layer containing a urethane-based pressure-sensitive adhesive as a main component, the surface protective film allowing the contamination of an adherend to be extremely suppressed, and being preferably excellent in wettability and reworkability. The surface protective film of the present invention includes, as an outermost layer, a pressure-sensitive adhesive layer containing, as a main component, a urethane-based pressure-sensitive adhesive containing a polyurethane-based resin; and when a pressure-sensitive adhesive layer side of the surface protective film is attached to a glass plate at 50° C. for 10 days and then the surface protective film is peeled from the glass plate, a residual adhesive strength on the peeled surface side of the glass plate is 3.0 N/19 mm or more.

Abstract: An article of manufacture is disclosed for incorporating into a civil engineering structure, for example a concrete structure, such as a floor. The article comprises a substantially fully cured thermosetting polymer resin and a particulate aggregate material having a Mohs hardness of from 3 to 9, preferably from 5 to 8. The article optionally comprises a reinforcing fiber. The hardness of the article can be closely matched to that of the surrounding structure. The article can be ground with a diamond tool to form a smooth transition with the surrounding structure. The article is particularly suitable for incorporation into an exposed surface of the structure.

Abstract: The invention relates to moisture-curing compositions which comprise at least one aromatic isocyanate group-bearing polyisocyanate and at least one dialdimine of formula (I). The compositions according to the invention have a longer open time and at the same time a shorter curing time, they are storage-stable and cure without forming bubbles. They are especially suitable as adhesives, sealing agents, potting compounds or coating materials, the use as sealing agents being especially advantageous.

Abstract: The disclosure provides an aqueous dispersion and ink jet inks comprising a colorant and an amphoteric polyurethane dispersant, wherein the amphoteric polyurethane dispersant comprises a reaction product of at least one basic amine urethane monomer, at least one acidic urethane monomer, and at least one urethane monomer comprising two or more isocyanates having improved bleed control, and optical density/chroma.

Abstract: A composite material comprises aggregate and an elastomeric composition. The elastomeric composition comprises the reaction product of an isocyanate component and an isocyanate-reactive component. The isocyanate component comprises a polymeric isocyanate, and optionally, an isocyanate-prepolymer. The isocyanate-reactive component comprises a hydrophobic polyol and a chain extender having at least two hydroxyl groups and a molecular weight of from about 62 to about 220. The chain extender is present in the isocyanate-reactive component in an amount of from about 1 to about 20 parts by weight based on 100 parts by weight of the isocyanate-reactive component. The aggregate may be rock, crumb rubber, and/or glass. The composite material has excellent physical properties and may be formed underwater, used in various locations, and used in various applications, such as for pavement, revetments, etc.

Abstract: A non-aqueous pigment dispersion includes a pigment, a non-aqueous dispersion medium, and a polymeric dispersant including at least one oxalylamide structural unit according to Formula (I): wherein: R1 represents a first polymeric moiety selected from the group consisting of a linear polymeric moiety, a star shaped polymeric moiety, a dendritic polymeric moiety, a branched polymeric moiety, and a hyperbranched polymeric moiety; and R2 represents a second polymeric moiety selected from the group consisting of a polyester, a polyether, a polyamide, a polyacrylate, a polymethacrylate, or copolymers thereof.

Abstract: There is described a process for producing a gel free hyperbranched polyamide polymer P having a polydispersity of at least 1.1 and a weight average molecular weight of at least 300 daltons, having primary amino groups (useful as a crosslinker). The process comprises the step of reacting Reagent A, a compound comprising at least one amino group (—NH2) and one functional group selected from the group consisting of a further amino group (—NH2), thiol (—SH) and a secondary amine radical (—NHR); (where R denotes a hydrocarbo group) (=functional amine) and Reagent B, an alpha-beta unsaturated Michael-reactive ester comprising a plurality of ester groups (=diester); in a molar ratio of amine A to diester B greater than 1 but less than 3 (preferably 2.1 to 2.9); to form the polyamide in a two stage reaction Michael addition and then amidation.

Abstract: The present invention discloses a semicrystalline, thermoplastic polyurethane which is comprised of the reaction product of (1) a hydrophobic polyol, (2) a polyisocyanate, and (3) a linear chain extender containing 5 carbon atoms or 7 to 12 carbon atoms; wherein the hydrophobic polyol has a number average molecular weight which is within the range of about 1,000 to about 4,000; wherein the semicrystalline, thermoplastic polyurethane has a weight average molecular weight which is within the range of 50,000 to 1,000,000; and wherein the semicrystalline, thermoplastic polyurethane has a melting point which is within the range of 80° C. to 150° C. This hydrophobic thermoplastic polyurethane offers a unique array of characteristics that are highly desirable for utilization in manufacturing a variety of products. For instance, it can be used in overmolding soft grips onto consumer products, in adhesives, and in protective coatings.

Abstract: The present invention provides two-component polyurethane compositions comprising, as one component, polyisocyanate compositions of the isocyanurate of one or more bis(isocyanatomethyl)cyclohexane or, preferably, a mixture of two or more of these, and of the isocyanurate of hexamethylene diisocyanate (HDI trimer), and, as the other component, a mix of a soft polyol having a hydroxyl functionality of from 2.5 to 5.0 and a molecular weight of from 500 to 3,000, and a hard polyol. Such compositions provide coatings, especially clear topcoats, which exhibit excellent scratch and mar and solvent resistance in addition to a good balance of hardness and flexibility without the need for increasing the volatile organic content (VOC) of the compositions. Also provided are compositions of a polyisocyanate compositions of the isocyanurate of one or more bis(isocyanatomethyl)cyclohexane with soft polyol which have lower VOCs.

Abstract: The invention relates to aqueous formulations comprising silane-modified polymeric binders having a siloxane content and inorganic nanoparticles, a process for the preparation thereof and the use thereof for the preparation of aqueous coating compositions.

Abstract: Disclosed is a composition comprising at least one polyol component (a) having an OH group content of 3% to 15% by weight relative to the total weight of the polyol component, and at least one isocyanate component (b) having an isocyanate group content of 5% to 15% by weight relative to the total weight of the isocyanate component. The polyol component (a) comprises at least one OH group-containing polyurethane prepolymer that is the product of a reaction between at least one compound a1. of the general formula (I) HO—R1—X—R2—OH??(I) and at least one di- or polyisocyanate a2. The isocyanate component (b) comprises at least one di- or polyisocyanate-terminated polylactone prepolymer. The composition can be used as erosion-resistant coating material.

Abstract: The present invention provides water swellable one-component sealants prepared by incorporation of polyols containing ethylene oxide (“EO”) into the backbone of the polymer. The inventive one-component hydrophilic polyurethane sealant contains a silane-terminated polyurethane prepolymer, a compound having an ethylene oxide content of at least about 40 wt. %, based on the weight of the compound and a catalyst, optionally, one or more of plasticizers, fillers, pigments, drying agents, light stabilizers, antioxidants, thixotropic agents and bonding agents. The one-component hydrophilic polyurethane sealant increases at least about 1.4% by weight and at least about 2.5% by volume upon exposure to water for 24 hours and are capable of curing in a high humidity environment (including underwater) without foaming and maintain physical characteristics such as hardness.

Abstract: A super hydrophobic coating composition that is a highly durable super hydrophobic transparent coating for glass, metal, and plastic, and automobile painted surfaces that is manually dispensable and may be easily applied to many substrates is provided. Moreover, the inventive super hydrophobic coating is user friendly as coating takes place at room temperature, and can be applied by a normal hand spray method. Embodiments of the coating dry within 30 minutes, and generate a super hydrophobic effect for ready use. The coating is useful to repel water droplets, dew drops, and dust particles in various applications such as solar panels, wind turbines surfaces, house hold components, metal coated furniture, marine equipment parts, marine sports equipment like speed boat screens, automobile wind shields, automobile plastic components, auto bodies and aerospace applications.

Abstract: The present disclosure relates to an aqueous dispersible polymer composition comprising: (a) at least one of: (i) a dendritic polymer in admixture with a hydrophilic functionalizing agent; and (ii) a hydrophilic functionalized dendrimer; and (b) a non-dendritic polymer capable of forming bonds with said dendritic polymer to thereby form a dendrimer-non-dendrimer (DND) polymer hybrid that is dispersible in the aqueous phase, methods of forming the same and uses thereof.

Abstract: A two-coat barrier system employing a coating of a water-dispersible or solvent-soluble polyurethane resin with innate gas and moisture vapor barrier properties and an additional coating of a multivalent metal cation to enhance the overall barrier performance without the need to add fillers.

Abstract: Biocompatible macromer compositions are provided including an isocyanate-functional polyalkylene oxide combined with at least one multi-functional isocyanate as a first component, and a multi-amino functional compound possessing multiple primary amines as a second component. The isocyanate-functional polyalkylene oxide has pendant polyalkylene oxide groups. The resulting biocompatible macromer composition can be employed as an adhesive or sealant for medical/surgical uses.

Abstract: The present invention relates to a polyurethaneurea solution having a polyurethaneurea having a structural unit of the formula (I) and terminated with at least one copolymer unit of the group consisting of a polyethylene oxide, a polypropylene oxide, and mixtures thereof.

Abstract: A multi-component variable hardness polyurethane system and method of creating a thermosetting composition having a particular hardness. In the preferred embodiment a polyurethane compound can be created having any desired hardness between 10 and 90 Shore A, by mixing the same two curative components in different proportions, according to the hardness desired, along with a stoichiometrically determined amount of isocyanate as a hardener.

Abstract: The present invention provides siliceous-based polyurea compositions, obtainable by reacting isocyanates, alkali silicates and hydratable aluminosilicates. Moreover, the present invention provides a process for the manufacture of these compositions, comprising the steps of mixing a hydratable aluminosilicate with an aqueous silicate and reacting this mixture with a polyisocyanate and/or a polyisocyanate prepolymer, optionally in the presence of a polyol and/or with the inclusion of an inert filler. Finally, the present invention provides the use of these compositions in the fields of aviation, automotive assemblies, construction, consumer products, fire protection, furniture components, insulation, shipbuilding and/or windmill construction. The compositions obtainable according to the present invention are lightweight, high load bearing, flame retarding materials.

Abstract: A protective sealant composition that is useful for sealing a colorant to a substrate, such as carpet. The protective sealant composition is formulated such that, upon drying, the composition forms a topcoat on the surface of the substrate, with the topcoat having a hard component and a soft component. The composition provides a durable protection against color fading and resoiling to the applied colorant, as well as to the rest of the surface of the substrate. The composition also provides wear resistance to the carpet by reducing the amount that the widths of the top ends of carpet fibers increase when subjected to wearing.

Abstract: A tin-containing polyurethane resin having a melting temperature of 40 to 180° C., measured by DSC at a heating rate of 10 K/min and prepared by carrying out a condensation reaction between a diorganotin compound and carboxyl groups of a carboxyl-functional polyurethane resin, wherein the molar ratio between the tin and the carboxyl groups is 1:2-20; and liquid coating compositions containing solid particles of the tin-containing polyurethane resin.

Abstract: The present invention provides polyurethanes including a reaction product of components including: (a) at least one isocyanate functional prepolymer including a reaction product of: (1) about 1 equivalent of at least one polyisocyanate; and (2) about 0.01 to about 0.5 equivalent of at least one polycarbonate polyol; and (b) about 0.01 to about 1 equivalent of at least one branched polyol having at least 3 hydroxyl groups; compositions, coatings and articles made therefrom and methods of making the same.

Abstract: Disclosed herein are materials such as a coating, comprising a lipolytic enzyme or organophosphrous compound degrading enzyme. Also disclosed herein are methods of visually detecting enzyme activity in a coating by contacting the coating with a substrate of an enzyme and a visual indicator that changes appearance upon production of a product of enzyme activity on a tack-free coating surface.

Abstract: The present invention relates to a composition comprising a hydrophobically modified alkylene oxide urethane polymer with pendant or end-capping tertiary amine groups, the conjugate acids of which have a pKa in the range of about 4.5 to about 6.5. The composition of the present invention is useful as a rheology modifier for paint formulations formulated over a wide pH range and is more stable to heat aging than higher pKa amine-modified HEURs.

Abstract: Provided is an aqueous polyurethane resin dispersion having a good film-forming property, and excellent mechanical properties and water resistance. The present invention is an aqueous polyurethane resin dispersion comprising water and a polyurethane resin (U) and satisfying all of the following conditions (1) to (6): (1) a urethane group content in the polyurethane resin (U) is 0.5 to 5.0 mmol/g, based on weight of the polyurethane resin (U); (2) a terminal amino group content in the polyurethane resin (U) is not more than 0.35 mmol/g, based on the weight of the polyurethane resin (U); (3) a number average molecular weight (Mn) of the polyurethane resin (U) is 10,000 to 1,000,000; (4) a ratio (Mw/Mn) of a weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polyurethane resin (U) is 1.5 to 3.5; (5) a melting temperature of the polyurethane resin (U) is 70 to 280° C.; and (6) a volume average particle diameter (Dv) of the polyurethane resin (U) is 0.01 to 1 ?m.

Abstract: Solutions of a salt of a diamine and of a diacid, more particularly concentrated solutions of hexamethylene diammonium adipate salt (“nylon salt”), useful starting materials for the production of polyamides, more specifically of PA66, are prepared by mixing a diacid and a diamine, at a salt concentration by weight of from 50% to 80%, in a first stage, to provide aqueous solutions of diacid and diamine having a diacid/diamine molar ratio of greater than 1.1 and, in a second stage, adjusting the diacid/diamine molar ratio, by adding diamine, to a value of from 0.9 to 1.1, preferably from 0.99 to 1.01, and in fixing the salt concentration by weight by, optionally, adding water thereto.