966 results about "Aqueous dispersion" patented technology

The invention discloses a pure bio-based polyhydroxyalkanoate adhesive as well as preparation and application thereof, and belongs to the technical field of degradable adhesives. According to the adhesive, polyhydroxybutyrate valerate or polyhydroxybutyrate hexanoate is used as a matrix, and the acid value reaches 2-15 mg KOH / g through molten end group activation; a reactive emulsifier with a hydrophilic-lipophilic balance value of 9-12 is introduced into a water phase, and the stable aqueous dispersion is prepared through phase inversion high-shear emulsification. The Z-average particle size of the dispersion is 0.12-0.30 [mu] m, and the content of the free surfactant is not higher than 30wt%. After the tackifying resin, the plasticizer and the vegetable wax are compounded, the bio-based carbon content of the obtained adhesive is not lower than 95%, and the volatile organic compound content is not higher than 100 mg / kg. The paper / paper heat sealing strength of the adhesive is not lower than 7.0 N / 15mm, the 180-degree peel strength is not lower than 7.5 N / 25mm, and the adhesive can pass repulping evaluation.

The invention discloses a positive electrode material for a zinc-bromine flow battery and a preparation method and application thereof, and belongs to the technical field of zinc-bromine flow batteries, the preparation method comprises the following steps: crushing and sieving an active carbon source, adding the active carbon source into a graphene oxide aqueous dispersion, stirring, centrifuging, removing supernate, drying, mixing with an activating agent, and activating in an inert atmosphere; washing to be neutral, drying and sieving to obtain a graphene / activated carbon composite material; and attaching the graphene / activated carbon composite material to a carbon-plastic bipolar plate to obtain the positive electrode material for the zinc-bromine flow battery. A graphene / activated carbon composite system is combined with a high-conductivity network, graded holes and surface functional groups, so that the reaction kinetics bottleneck of a traditional carbon material Br2 is broken through.

The invention discloses a pure bio-based PHA aqueous dispersion as well as a preparation method and application thereof, and belongs to the technical field of pure bio-based polymer aqueous dispersion. According to the dispersion, polyhydroxyalkanoate is used as a unique film forming matter, Pickering solid particles and a natural surfactant are adopted for synergistic stabilization, and a bio-based plasticizer can be selected. The emulsion or slurry with the polyhydroxyalkanoate content of 40-85wt% and the particle size of 0.2-3m is prepared through a melting high-pressure homogenization method, a low-temperature wet grinding method or a solvent replacement method. The coating does not contain petrochemical polymer protective colloid and perfluorinated and polyfluoroalkyl substances, and the bio-based content is greater than or equal to 99%. Due to the excellent stability, rheological property and film-forming property of the modified starch, the modified starch becomes an ideal basic material for constructing a multi-layer programmable controlled release and degradation functional coating system, can be used in the fields of paper-based barrier coatings, adhesives, advanced crop seed coats and the like, realizes excellent barrier, bonding and controlled release properties, meets the industrial compost and repulping property standards, and has wide application prospects. The method has green, environment-friendly and industrial potential.

The invention provides a PHA dispersion emulsion as well as a preparation method and application thereof, and belongs to the field of high polymer materials. The invention aims to solve the technical problem that the prior art cannot simultaneously meet the requirements of the polyhydroxyalkanoate water dispersion system on extremely low temperature natural film-forming property, excellent comprehensive performance after film formation and long-term storage stability. The method is characterized in that a polyhydroxyalkanoate polymer with specific molecular weight and polydispersity index range, a coalescing agent 2, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate with a specific chemical structure and a specific type of aliphatic polyisocyanate cross-linking agent compatible with water dispersion are strictly limited and combined. Through the synergistic effect generated by the unique ternary combination, the minimum film forming temperature of the prepared emulsion can be reduced to 6-10 DEG C, a film can be naturally formed without hot pressing, and the formed film has excellent mechanical property, water resistance and adhesive force and has excellent storage stability of at least one year.

The invention discloses a PHA-acrylic acid structural unit water-based dispersion based on interface engineering regulation and control, a preparation method thereof and application of a paper-based barrier coating, and belongs to the technical field of high polymer materials, interface engineering and water-based coatings. The stable interface layer is constructed in situ between the crystalline PHA and the acrylic resin through the amphiphilic polymer, so that the problems of poor compatibility and film forming defects of a bio-based material are effectively solved. The dispersion can realize excellent waterproof, oil-proof and gas barrier effects by only needing a relatively low coating weight, and the material consumption is remarkably reduced. The unique gradient structure of the coating has excellent mechanical adhesive force and efficient re-pulping and recycling characteristics, and the technical defect that a traditional barrier coating is difficult to recycle is overcome. And an ideal solution with high performance and high safety is provided for green packaging.

The invention discloses a bio-based PHA oil-resistant and moisture-permeable coating for hamburger paper, coated paper and a preparation method, and belongs to the technical field of bio-based high polymer materials and paper-based food packaging. The coating is a PHA aqueous dispersion, and mainly comprises a semi-crystalline matrix PHA and a low-crystallinity or amorphous toughening PHA. The core of the coating is that after the coating is dried to form a film, a functional gradient structure can be spontaneously formed in the thickness direction of the coating: an interface layer close to a paper base is rich in toughening PHA so as to enhance toughness and adhesive force; and the surface layer of the coating is rich in matrix PHA so as to maximize the oil resistance. By means of the functional gradient structural design, the packaging material integrates oil resistance, moisture permeability and flexibility of the packaging material, has the degradable environment-friendly characteristic and is suitable for packaging high-grease food.

The present invention relates to a composition comprising an aqueous dispersion of biodegradable polymer particles, a method of preparing the composition, and a method of preparing a coated substrate comprising the composition. The composition is useful as a coating applied to a substrate, particularly a paper substrate. The coated paper is useful as a single layered barrier coated paper or paperboard.

The invention discloses a cellulose paper-based diaphragm for a zinc-iodine battery as well as a preparation method and application of the cellulose paper-based diaphragm. The diaphragm is of a three-layer composite structure and comprises a matrix layer formed by paper pulp fibers such as softwood pulp, hardwood pulp, bamboo pulp or straw pulp through a wet papermaking technology, and compact functional layers which cover the two sides of the matrix layer and are formed by oxidized nanocellulose (TOCN). The preparation method mainly comprises the following steps: preparing the paper-based diaphragm matrix through wet papermaking, coating the two sides of the paper-based diaphragm matrix with TOCN aqueous dispersion, and finally carrying out hot-pressing drying treatment to enable the three layers to be tightly combined. According to the invention, the nano aperture and the surface negative electricity functional group of the TOCN layer are utilized, so that physical blocking and electrostatic repulsion of polyiodide ions can be realized at the same time, and the shuttle effect is effectively inhibited; and the uniform pore channels can guide zinc ions to uniformly deposit and inhibit dendritic crystal growth. The diaphragm is green in raw material, simple in process and low in cost, and the cycle life and coulombic efficiency of the battery can be remarkably improved when the diaphragm is applied to the zinc-iodine battery.

The invention discloses an antiskid sewage-resistant waterborne coating and a preparation method thereof, and relates to the technical field of tableware coatings. The water-based paint comprises a liquid A and a liquid B, the liquid A comprises the following components in parts by weight: 35-60 parts of emulsion type organic silicon aqueous dispersion resin; 3 to 10 parts of maleic anhydride grafted polypropylene wax emulsion; 5-10 parts of an elastomer modified acrylic dispersion; 0.5 to 1.2 parts of a dispersant; 1-3 parts of a thickening agent; 3-8 parts of a nanoscale aluminum oxide dispersion liquid; 15-25 parts of a water-based color paste; 0.3-1 part of an emulsifying ripple auxiliary agent; 0.1-1 part of a substrate wetting agent; 0.1 to 1 part of a defoaming agent; 3-5 parts of deionized water; the liquid B comprises the following components in parts by weight: 90-100 parts of a water-based isocyanate curing agent, 0.3-0.8 part of a dehydrating agent, 5-8 parts of an adhesion promoter and 2-5 parts of a coalescing agent. The invention provides an innovative two-component water-based paint system, through the synergistic effect of the components after the liquid A and the liquid B are mixed, the multiple requirements of tableware or catering auxiliary appliances on the skid resistance, stain resistance, adhesive force and environment friendliness of the coating are comprehensively met, and the coating completely meets the high-standard requirements of food contact materials.

The invention discloses three-dimensional reticular porous MOFs / MXene cellulose composite aerogel as well as a preparation method and application thereof, and belongs to the technical field of aerogel. The preparation method comprises the following steps: adding divalent metal salt into an MXene aqueous dispersion to obtain a mixed dispersion I; sequentially adding the mixed dispersion liquid I and a borax aqueous solution into the mixed dispersion liquid of cellulose nanofibers and polyvinyl alcohol under a heating condition, stirring and dispersing, cooling, and freeze-drying to obtain double-crosslinked network aerogel; the preparation method comprises the following steps: preparing a bi-crosslinked network aerogel, immersing the bi-crosslinked network aerogel into a solution containing imidazole ligands for an in-situ reaction, and then washing and drying to obtain the three-dimensional network porous MOFs / MXene cellulose composite aerogel which has high MOFs loading capacity and excellent stability, can realize efficient adsorption of antibiotics, and is simple in preparation method and suitable for large-scale production.

The present invention relates to a composition comprising an aqueous dispersion of biodegradable polymer particles, a method of preparing the composition, and a method of preparing a coated substrate comprising the composition. The composition is useful as a coating applied to a substrate, particularly a paper substrate. The coated paper is useful as a single layered barrier coated paper or paperboard.

This invention discloses a bio-based PHA oil-blocking and moisture-permeable coating for hamburger paper, the coated paper, and its preparation method, belonging to the fields of bio-based polymer materials and paper-based food packaging technology. The coating is an aqueous dispersion of PHA, mainly comprising semi-crystalline matrix PHA and low-crystallinity or amorphous toughening PHA. Its core feature is that after the coating dries and forms a film, it spontaneously forms a functional gradient structure along the coating thickness direction: the interfacial layer near the paper substrate is rich in toughening PHA to enhance toughness and adhesion; while the surface layer is rich in matrix PHA to maximize oil-blocking performance. Through this functional gradient structure design, this invention balances the oil-blocking, moisture-permeable, and flexible properties of the packaging material, and possesses biodegradable environmental characteristics, making it suitable for high-oil food packaging.

The invention discloses a sustained-release pill as well as a preparation method and application thereof, and belongs to the technical field of medicines. The sustained-release pill comprises a pill core and a coating layer coated outside the pill core, the pellet core is prepared from the following raw materials in parts by mass: 8 to 14 parts of loxoprofen sodium, 30 to 60 parts of a filling agent, 3 to 10 parts of an adhesive, 2 to 10 parts of a disintegrating agent, 0.1 to 2 parts of a penetration enhancer, 0.05 to 0.2 part of a pH regulator, 0.1 to 0.5 part of a surfactant and 0 to 20 parts of an auxiliary agent; the coating layer is prepared from an aqueous dispersion liquid containing acrylic resin; the coating layer is prepared from an aqueous dispersion liquid containing acrylic resin. Aiming at the drug characteristics of loxoprofen sodium, the loxoprofen sodium sustained-release tablet is composed of specific auxiliary materials, the drug composition is optimized, the drug release rate is accurately controlled, the bioavailability and stability of the drug are effectively improved, and the loxoprofen sodium sustained-release tablet has a good application prospect in preparation of antipyretic and analgesic drugs.

To provide hollow particles in which the dielectric dissipation factor is decreased, and the performance stability in high-humidity environment is improved. Hollow particles comprising a shell, which contains a resin, and a hollow portion surrounded by the shell, wherein the hollow particles have a void ratio of 50% or more; wherein the shell contains a polymer as the resin, and a content of a crosslinkable monomer unit is 60% by mass or more in 100% by mass of all monomer units of the polymer; and wherein an aqueous dispersion of the hollow particles, which is obtained by dispersing the hollow particles with a volume of 0.35 cm3 in 100 mL of deionized water, has a pH of 6.5 or more and 7.5 or less and a conductivity of 50 μS / cm or less.

The invention relates to the technical field of garment materials, and discloses a high-moisture-absorption breathable polyester fabric and a preparation method thereof. The preparation method of the high-moisture-absorption breathable polyester fabric comprises the following steps: mixing terephthalic acid, ethylene glycol, a modified flame-retardant comonomer and tetrabutyl titanate, and carrying out esterification and melt polycondensation to obtain modified polyester; mixing the modified polyester and the polyester master batch, and spinning to obtain the high-performance hollow polyester fiber. Blending and knitting high-performance hollow polyester fibers and cotton fibers to obtain polyester fabric; the preparation method comprises the following steps: modifying palygorskite with a silane coupling agent KH-550, and then loading phosphorus-doped carbon dots to obtain loaded modified palygorskite; the polyester fabric is soaked in the polydopamine finishing liquid and the loaded modified palygorskite aqueous dispersion liquid, and the high-moisture-absorption breathable polyester fabric is obtained. The high-moisture-absorption breathable polyester fabric not only has good moisture absorption and breathability, but also has excellent flame retardance.

The invention relates to the technical field of memristors, and provides a chitosan-based memristor which comprises a substrate, a buffer layer, a composite dielectric layer and a top electrode which are sequentially stacked from bottom to top, the buffer layer is formed by spin-coating a PEDOT: PSS aqueous solution on the substrate and then carrying out heat treatment; the composite dielectric layer is formed by spin-coating the buffer layer with an ultrasonic composite solution formed by a graphene oxide aqueous dispersion and a chitosan acetic acid solution and then carrying out heat treatment. By adopting a collaborative architecture of the chitosan-graphene oxide composite dielectric layer and the PEDOT: PSS buffer layer, the prepared bio-based memristor has the effects of relatively high switching ratio, relatively low operating voltage and good performance stability. Meanwhile, based on stable high and low resistance states of the device, all seven basic logic operations including a NOT gate, an AND gate, an OR gate, a NAND gate, a NOR gate, an XOR gate and an XNOR gate are completely realized on a single bio-based platform, the function accuracy can reach 100%, and an unexpected effect is achieved.

A dispersion, methods of making the same, applications of the dispersion to graphitic material and the resulting coated particles are disclosed. The dispersion includes ≤55% wt. coal tar pitch (softening point 100° C.-95° C.), ≤60% wt. dispersant, and the balance a non-aromatic solvent such as water or alcohol. Pitch particles in the dispersion are preferably ≤10 μm with a distribution of D50<15 μm. The pitch particles are micronized, such as by dry and / or wet milling with the dispersant and aqueous solvent to achieve the desired pitch particle size and distribution. This aqueous dispersion may be mixed with natural or synthetic graphitic material having a diameter of 5-20 μm in a ratio of 5%-30% pitch to graphite, dried and carbonized to form coated particles having a graphitic core at least partially coated by pitch particles.

The invention provides a modified aspartate resin and an aqueous dispersion, and relates to the technical field of aqueous emulsions. The modified aspartic ester resin is obtained by reacting hydrophilic aspartic ester resin with a polyisocyanate compound and then reacting with hydrophobic aspartic ester resin, has moderate hydrophilicity and can be self-emulsified and dispersed in water to form an aqueous dispersion, and a coating cured by the aqueous dispersion is relatively good in water resistance.

The invention discloses a paper-based molded coffee capsule capable of being naturally composted, a PHA aqueous dispersion in-situ film forming barrier heat-sealing composite layer, a preparation method and application thereof, and belongs to the field of degradable packaging and single-cup extraction capsules. The capsule body is formed by molding paper pulp and is provided with a side wall, a bottom wall and a mouth flange; the biodegradable polyester-based film sealing component is connected to the flange in a sealing manner; and the polyhydroxyalkanoate barrier heat-sealing composite layer covers the inner surface of the body and the sealing surface of the flange. The composite layer is obtained by in-situ film forming of a particle size gradient double-layer aqueous dispersion and comprises a permeation anchoring layer located in paper pulp pores and a continuous compact layer located on the outer side in the thickness direction. The flange is a hot-pressing densified area, and a local thickening heat sealing ring is formed on the sealing face of the flange. Through physical anchoring of the small-particle-size components and surface film forming of the large-particle-size components, the moisture and oxygen blocking and interface bonding performance is achieved, and the brewing sealing performance is guaranteed.

To provide a method for producing an aqueous alumina dispersion that forms a highly stable aqueous alumina dispersion utilizing only the protective stability of water-soluble aliphatic amino acids and minimizes the content of alkali metal components and halogen elements.SOLUTION: In the aqueous alumina dispersion, (a) an average particle diameter of dispersed particles is in the range of 5 to 500 nm, (b) alumina particles when the alumina-containing aqueous dispersion is dried at 100°C are composed of one or more of boehmite and pseudo-boehmite, (c) a pH of the aqueous alumina dispersion is in the range of 2.0 to 5.3, (d) the aqueous alumina dispersion comprises a water-soluble aliphatic amino acid, (e) an alumina (Al2O3) equivalent concentration of aluminum contained in the aqueous alumina dispersion is in the range of 0.3 to 11.5 mass%, and (f) a time until the viscosity of the aqueous alumina dispersion becomes 100,000 mPa s or more when a base is added to the aqueous alumina dispersion to adjust the pH to 5.4 to 10 is 24 hours or more.SELECTED DRAWING: Figure 1

A method for preparing a heavy-duty tire with a natural rubber (NR) modified by graphene / carbon blacks varying in particle size synergized with a vulcanization system is provided. Carbon blacks varying in particle size are subjected to surface modification to obtain an graphene oxide / carbon blacks varying in particle size aqueous dispersion. Subsequently, a graphene oxide / carbon blacks varying in particle size modified NR masterbatch is prepared using an aqueous-phase synergistic aggregating precipitating process. Finally, a natural rubber heavy-duty tire is prepared from graphene / carbon blacks varying in particle size synergistically vulcanized modified natural rubber through a molding process. Compounding of graphene with the carbon blacks varying in particle size is utilized to improve dispersion of reinforcing fillers within the rubber matrix. Adjustment of a ratio of a vulcanizing agent to an accelerator is utilized to regulate a cross-linked network structure of the rubber.

The application discloses a paper-based moulded coffee capsule capable of natural composting, a PHA aqueous dispersion in-situ film-forming barrier heat-sealing composite layer and a preparation method and application thereof, and belongs to the field of degradable packaging and single-cup extraction capsules. The capsule comprises a capsule body formed by moulded paper pulp, a side wall, a bottom wall and a mouth flange, a biodegradable polyester-based film sealing member sealed to the flange, and a polyhydroxyalkanoate barrier heat-sealing composite layer coated on the inner surface of the body and the sealing surface of the flange. The composite layer is obtained by in-situ film-forming of a particle size gradient double-layer aqueous dispersion, and comprises an infiltration anchoring layer located in the pores of the paper pulp and a continuous dense layer on the outside along the thickness direction. The flange is a heat-pressed densification area, and a locally thickened heat-sealing ring is formed on the sealing surface of the flange. The application realizes the moisture and oxygen barrier and interface bonding performance through physical anchoring of small particle size components and surface film-forming of large particle size components, and guarantees the brewing sealing performance.

The present invention relates to a method for preparing a liquid dispersion of MXene, comprising: S1, providing an aqueous dispersion of a monolayer or a few-layer MXene; S2, providing a lignin fraction; the preparation method comprising: adding lignin to an organic solvent, stirring and dissolving the lignin, and then centrifuging to obtain a supernatant; first subjecting the supernatant to rotary evaporation to remove most of the organic solvent, and then vacuum drying to obtain a lignin fraction corresponding to the organic solvent; S3, dissolving the lignin fraction in an organic solvent, then adding the aqueous dispersion of the monolayer or few-layer MXene to the organic solution of lignin, stirring for reaction, then centrifuging the product, and repeatedly washing the precipitate with deionized water until the supernatant is clear; S4, separating the precipitate, adding an organic solvent or deionized water to the precipitate, and homogenizing to obtain a MXene organic phase dispersion or aqueous phase dispersion of a predetermined concentration. The present invention can provide a MXene liquid dispersion that can be stably stored.

The invention discloses a performance-adjustable aramid nanofiber reinforced polyvinyl alcohol hydrogel and a preparation method thereof, and the preparation method comprises the following steps: S1, through a high-speed shearing sequential control method, realizing the conversion of aramid fibers from a micron level to a nano level; s2, dissolving and dispersing aramid fibers by using a mixed acid system to obtain an ANFs stock solution, dropwise adding deionized water into an ice bath, and centrifuging to obtain an ANFs aqueous dispersion system; s3, PVA, TA and ANFs are heated and stirred, and a uniform PVA / ANFs-TA mixed solution is obtained; the preparation method comprises the following steps: mixing a PVA solution with ANFs-TA, adding a borax solution into the mixed solution, heating, pouring into a mold to obtain PVA / ANFs-TA hydrogel, and adjusting the concentration of TA to obtain super-stretched hydrogel (TA 2%) and self-repairing hydrogel (TA 0.8%). The prepared self-repairing hydrogel solves the problems that a single hydrogel material is insufficient in mechanical strength and limited in self-repairing capacity; the super-stretching hydrogel can realize 50000% super-stretching rate and underwater long-term adhesion.

The invention provides a polyhydroxyalkanoate aqueous composite dispersion and a preparation method and application thereof, the polyhydroxyalkanoate aqueous composite dispersion comprises a polyhydroxyalkanoate aqueous dispersion, an acrylic emulsion and a stabilizer, and the stabilizer is a surfactant with an HLB value of 12-14 or a combination thereof. By adding the surfactant with a specific HLB value, the polarity difference between particles is reduced, and the stability of a PHA aqueous dispersion and acrylic emulsion composite system is improved. The preparation method is simple in production process and has a wide application prospect.

The invention is applicable to the technical field of material preparation and electrochemical sensing, and discloses a graphdiyne oxide gold nanoparticle composite electrode, a preparation method and application of the graphdiyne oxide gold nanoparticle composite electrode in a non-enzymatic glucose electrochemical sensor. Preparing the prepared graphdiyne oxide into an aqueous dispersion, taking carbon cloth as a substrate electrode, soaking the carbon cloth in the graphdiyne oxide dispersion after ethanol soaking, drying and surface treatment, drying, then soaking the carbon cloth in the prepared gold nanoparticle solution, and heating and drying to obtain the graphdiyne oxide gold nanoparticle composite electrode; the graphdiyne oxide and the gold nanoparticles are uniformly distributed on the surface of the carbon cloth. Due to the fact that rich oxygen-containing groups on the graphdiyne oxide can cooperate with the gold nanoparticles to promote catalytic oxidation of glucose, the non-enzymatic glucose electrochemical sensor prepared based on the electrode material has high catalytic activity on glucose and shows high sensitivity, selectivity and stability.

The invention provides a modified graphene / PMIA nano composite material and a preparation method thereof, and relates to the field of electromagnetic shielding materials, the preparation method comprises the following steps: S1, adding a modifier into an aqueous dispersion of graphene oxide, and carrying out solid-liquid separation and drying to obtain modified graphene oxide powder; s2, adding the modified graphene oxide powder into a solvent, dispersing to a uniform state, standing, and taking upper-layer dispersion liquid; s3, adding lithium salt into the dispersion liquid until the lithium salt is fully dissolved; s4, adding PMIA short fibers into the dispersion liquid, and heating and dissolving the PMIA short fibers to prepare a spinning solution; s5, spinning by adopting a wet spinning process to prepare a wet film, and removing the solvent to obtain a graphene / PMIA nano composite material; the graphene oxide is subjected to specific process steps including a specific modification process, alcohol washing and the like, the composite material obtained after the modified graphene oxide and the PMIA short fibers are combined is tighter, and the electromagnetic shielding effectiveness can reach 50 dB; the whole process is simpler, the raw material selectivity is wide, and the process is not limited by the structural form of raw material fiber bundles.

To provide a method for producing a conductive polymer dispersion liquid in which a conductive composite exhibiting excellent conductivity is dispersed, and a method for producing a conductive laminate using the dispersion liquid.SOLUTION: A method for producing a conductive polymer dispersion liquid comprises a step of adding an oxidizing agent that polymerizes a monomer forming a π-conjugated conductive polymer to a reaction liquid containing a polyanion, the monomer forming the π-conjugated conductive polymer, and an aqueous dispersion medium to cause a polymerization reaction and to form a conductive composite containing the π-conjugated conductive polymer and the polyanion, wherein a ratio represented by absorbance A at 600 nm of the reaction liquid immediately before addition of the oxidizing agent divided by a concentration C on a mass basis of the monomer contained in the reaction liquid (absorbance A / concentration C) is 90 or more and 650 or less.SELECTED DRAWING: None

The present invention relates to an aqueous coating composition, preferably an aqueous sanding surfacer or primer-surfacer, comprising an aqueous epoxy resin dispersion (A), an aqueous amine-functional resin dispersion (B) and an aromatic carboxylic acid (C). The aqueous dispersion (B) comprises at least one specific di- and / or polyfunctional monomeric amine (A1) and at least one resin component (RC), the resin component (RC) comprising at least one specific polyfunctional organic amine (A2). The present invention also relates to a kit comprising a base varnish comprising an aqueous epoxy resin dispersion (A) and a curing component comprising an aqueous amine-functional resin dispersion (B) and an aromatic carboxylic acid (C). The present invention also relates to a method for preparing a coating on a substrate and a coated substrate obtained by the method. The cured coating formed from the composition exhibits good adhesion to the substrate under humid conditions, high intercoat adhesion and blister stability, without negatively affecting the excellent sanding properties and good stone chipping properties.

The present invention relates to a method of preparing a superabsorbent polymer. More particularly, the preparation method performs a polymerization reaction of a monomer in the presence of an aqueous dispersion of hydrophobic particles, thus enabling the preparation of a superabsorbent polymer having a high surface tension and an improved absorption rate without deterioration in absorption properties.