28 results about "Melamine formaldehyde resin" patented technology

This application relates to a highly acid and alkali resistant pigment, Red 48:1, and its preparation process, belonging to the field of chemical pigment manufacturing technology. The pigment is prepared from 2B acid, sodium nitrite, 2,3 acid, a barium-lanthanum-calcium multimetallic salt component, aminotrimethylenephosphonic acid, zirconium salt, melamine-formaldehyde resin prepolymer, epoxy resin emulsion, silane coupling agent, and surfactant. The preparation process includes sequential diazotization and coupling reactions, followed by a co-lake reaction with the addition of multimetallic salts; then interfacial anchoring via aminotrimethylenephosphonic acid, and inorganic deposition hybridization via droplet addition of zirconium salt; finally, a staged crosslinking coating reaction is performed with the aforementioned resin and coupling agent. This invention constructs an inorganic-organic hybrid coating layer in situ on the pigment core surface of the multimetallic lake, physically blocking the penetration pathways of acid and alkali ions, thus improving the pigment's resistance to acid and alkali bleeding and its resistance to ultraviolet aging.

This invention discloses a method for preparing superhydrophobic aerogels under ambient pressure based on framework regulation and its application. The invention involves a multi-component composite of carboxymethyl cellulose, aramid fiber, carboxylated nitrile rubber, melamine-formaldehyde resin, modified montmorillonite, hydrophobic silica, and an organosilicon waterproofing agent. A vertical pore template is constructed through directional freezing, followed by gradient solvent displacement and ambient pressure drying to finally solidify the superhydrophobic-superoleophilic aerogel. This invention successfully overcomes the core challenge of structural collapse caused by capillary forces during ambient pressure drying through the synergistic enhancement of the organic-inorganic hybrid framework and surface energy regulation, achieving a balance between low shrinkage, high porosity, and stable superwetting properties. The aerogel of this invention possesses excellent mechanical strength and elasticity, and its functionality can be expanded by introducing photothermal fillers. The process equipment is simple and energy-efficient, providing an economical and feasible technical path for the large-scale preparation of high-performance superhydrophobic aerogels.

The application belongs to the technical field of bamboo processing, and particularly relates to a preparation method of improved reconstituted bamboo, wherein the defibrated bamboo bundle is stepwise impregnated by preparing etherified melamine formaldehyde resin and modified phenolic resin. First, the bamboo bundle is impregnated by the etherified melamine formaldehyde resin with small molecular size, low viscosity and good water solubility, so that the etherified melamine formaldehyde resin can deeply enter the cell wall and the inner part of the micropore of the bamboo, fully fill the pores and block the hydrophilic channels, and meanwhile, the mildewproof agent is uniformly delivered to the inner part of the bamboo. Further, the bamboo bundle is impregnated by the phenolic resin with large molecular size and modified by flexible sugar ring units, so that the phenolic resin can be enriched on the surface of the bamboo bundle and the bonding interface, a flexible bonding layer is formed, the flexible molecular chain can buffer the residual stress of the interface, the bonding layer flexibility and the bonding strength of the bamboo bundle are improved, and the structural stability of the reconstituted bamboo during long-term use is further ensured.

This application relates to the field of adhesives, and more specifically, to a UV hydrolyzable adhesive and its preparation method. It comprises the following raw materials by weight percentage: 40-58% modified polyurethane acrylate, 10-20% tackifier and absorbent polymer, 1-3% photoinitiator, and the balance being an active diluent; the tackifier and absorbent polymer is composed of a polyurethane associative thickener, methanol-etherified melamine-formaldehyde resin, absorbent fibers, and hydroxyl acrylate. By specifically selecting the polyurethane associative thickener, methanol-etherified melamine-formaldehyde resin, absorbent fibers, and hydroxyl acrylate as the main components of the tackifier and absorbent polymer, and optimizing their ratio, the adhesion strength and hydrolysis detachment effect of the UV hydrolyzable adhesive on the surfaces of lightweight composite materials such as carbon fiber composites and glass fiber reinforced plastics are significantly improved.

The present application provides a kind of microcapsule aqueous dispersion and preparation method and its application in water-based photosensitive solder resist ink.The microcapsule aqueous dispersion is shell-core structure, the core material of the microcapsule aqueous dispersion is water-soluble basic epoxy acrylate resin, the wall material of the microcapsule aqueous dispersion is ultraviolet light degradable resin, and the ultraviolet light degradable resin is selected from urea-formaldehyde resin or melamine-formaldehyde resin.Microcapsule aqueous dispersion is configured into water-based photosensitive solder resist ink with conventional water-based alkali-soluble epoxy acrylate resin, hydrophilic multifunctional acrylate reactive diluent, photoinitiator, auxiliary agent and water.This application realizes the physical isolation and light-controlled release of basic active component through microcapsule technology, fundamentally solves the poor long-term storage stability of traditional water-based solder resist ink, the poor pattern accuracy caused by uneven volatilization of amine neutralizer, and the contradiction between alkali-soluble requirement and chemical resistance.

This invention discloses a self-healing microcapsule for asphalt pavement cracks and its preparation method, relating to the field of road engineering materials technology. The structure includes: the microcapsule comprises a composite modified wall material and a core material, wherein the core material forms an interpenetrating network structure after curing; the mass ratio of the composite modified wall material to the core material is 1:(1.5-2.5); the composite modified wall material, by weight, consists of 60-75 parts of urea-formaldehyde resin prepolymer, 5-15 parts of glass fiber, 8-12 parts of melamine-formaldehyde resin, and 400 parts of polyethylene glycol. The wall material consists of 5-8 parts of silane coupling agent KH-5501-3 parts, polyethylene glycol diglycidyl ether 0.5-1.0 parts, and dispersant 0.8-1.2 parts; the core material, by weight, consists of 75-85 parts of asphalt recycling agent with an aromatic content ≥45%, 2-5 parts of maleic anhydride, 0-15 parts of epoxy resin E-511, and 2-3 parts of microcapsule-encapsulated dicyandiamide latent curing agent; this invention optimizes the design of the wall and core materials, enhances performance and compatibility, improves the preparation process, improves microcapsule performance, reduces costs, and enhances the overall benefits and sustainability of road surfaces.

The application belongs to the technical field of adhesives, and relates to a kind of organic silicon foaming glue and its preparation method.The organic silicon foaming glue includes component A and component B, the component A includes the following raw materials: vinyl silicone oil, hydroxyl silicone oil, fumed silica, platinum catalyst;The component B includes the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsule, inhibitor;Wherein, the core material of the flame-retardant microcapsule is graphene, and the shell material from inside to outside is modified acrylic resin and melamine formaldehyde resin in turn.The organic silicon foaming glue provided in the application solves the problem of high filling amount of existing foaming glue flame retardant and easy leakage of flame retardant in the prior art, and the limiting oxygen index (LOI) of the prepared foaming glue is improved to more than 32%, the vertical burning grade reaches UL94V-0 level, and no melt dripping occurs;The foaming glue remains stable in performance in the range of-60℃~200℃, and after high-low temperature cycle-40℃ / 2h→150℃ / 2h, cycle 10 times, the compression permanent deformation rate is less than or equal to 15%.

This invention belongs to the field of electromagnetic wave absorbing materials technology, and specifically discloses a hollow spherical Ti3C2T x @Molybdenum disulfide@cobalt / carbon composite materials, their preparation methods, and applications. The preparation method includes the following steps: reacting formaldehyde with melamine to prepare melamine-formaldehyde resin particles, ultrasonically dispersing them in water, and then adding Ti3C2T. x Suspension, stirred, melamine-formaldehyde resin particles with Ti3C2T x Self-assembly yields the core-shell material Ti3C2T x @MF; Ti3C2T x @MF, molybdenum source, and sulfur source are dispersed in water in a certain proportion and subjected to a hydrothermal reaction. The hydrothermal reaction product is washed and dried to obtain hollow spherical Ti3C2T x @Molybdenum disulfide composite material HTM; A dimethylimidazole alcohol solution is slowly added to a mixed alcohol solution of HTM and a cobalt source, stirred for a set time, and then allowed to stand for a set time to obtain HTM@ZIF67; HTM@ZIF67 is then pyrolyzed in an inert atmosphere to obtain hollow spherical Ti3C2T. x @Molybdenum disulfide@cobalt / carbon composite material. This material combination can effectively promote the attenuation of electromagnetic waves and reduce the material's filler content.

This invention discloses a hyperbranched polyamide modifier, a modified melamine-formaldehyde resin, and their applications, belonging to the technical field of melamine-formaldehyde resin modification. The modifier is prepared from tetraethylenepentamine, ethylenediaminetetraacetic acid (EDTA), a catalyst, and water; the molar ratio of tetraethylenepentamine to EDTA is 1:(0.3-1); the amount of catalyst is 0.5-1.5 wt% of the total mass of tetraethylenepentamine and EDTA. The hyperbranched polyamide modifier prepared by this invention is compatible with melamine-formaldehyde resin, improving toughness and appropriately reducing formaldehyde release.

FIELD: radio engineering industry; instrument engineering; aviation industry.SUBSTANCE: invention relates to lacquer protective compositions and can be used in the radio engineering industry, instrument engineering, aviation industry, and other sectors of the national economy for the anti-corrosion protection of aluminum, copper, iron, and their alloys. A lacquer composition is proposed, including 0.6-1.10 g / l of 50% butanolized melamine-formaldehyde resin K-421-02, 0.6-1.10 g / l pentaphthalic varnish “ПФ-060”, 0.78-1.05 g / l triethylamine, 15.8-16.5 g / l resin “BMA”-0120, which is a solution in isopropyl alcohol hydrolyzed a product consisting of a maleinated mixture of linseed and dehydrated castor oils, 0.025-0.03 g / l of manganese sulfate and water up to 1 liter.EFFECT: invention provides a protective composition capable of forming a corrosion-resistant transparent coating on the surface of metals, while reducing the amount of solvents in the composition.1 cl, 2 ex

The present application belongs to the technical field of environmental protection chemical materials, and particularly relates to a green and environment-friendly high-methyl-etherified resin adhesive and a preparation method thereof. The adhesive comprises a high-methyl-etherified melamine formaldehyde resin matrix and temperature-sensitive slow-release capsules dispersed therein. The capsules are composed of a temperature-sensitive liposome encapsulating a formaldehyde adsorbent and a VOC adsorbent. The preparation method comprises the following steps: synthesizing the resin matrix through a two-step method; preparing the temperature-sensitive liposome by using an ether injection method to encapsulate the adsorbents, and then obtaining capsule powder through freeze-drying; and finally, compounding the two. Through the intelligent response release characteristics of the temperature-sensitive capsules, the present application can accurately release the adsorbents in the curing temperature range of the adhesive, realize in-situ efficient capture of free formaldehyde and volatile organic compounds generated in the curing process, thereby significantly reducing the pollutant emissions in the coating process, and not affecting the original mechanical properties and workability of the adhesive.

This invention relates to the field of polymer material modification, and discloses a highly dispersed flame-retardant and antistatic ABS masterbatch and its preparation method. The method includes: preparing an LS-CNC composite carrier by mixing and drying an aqueous suspension of sodium lignosulfonate and cellulose nanocrystals; preparing APP / LS-CNC composite particles by loading ammonium polyphosphate onto the surface of LS-CNC; preparing an organic-inorganic dual-stage flame-retardant framework composite powder by ultrasonically co-dispersing the APP / LS-CNC composite particles with sepiolite mineral fibers and then spray drying; preparing MF@IL-MMT composite particles by in-situ polymerization and coating of ionic liquid intercalated montmorillonite with melamine-formaldehyde resin prepolymer; and preparing the masterbatch by melt-blending and extruding the above composite powder, MF@IL-MMT composite particles, conductive mica powder, and tetraneedle-shaped zinc oxide whiskers with ABS resin. This invention achieves durable antistatic properties across the entire humidity range.

This invention relates to the field of composite panels and discloses a wear-resistant and UV-resistant fiberglass-silicon core composite panel and its preparation method. The composite panel comprises melamine-faced paper, fiberglass mat, and calcium silicate board impregnated with adhesive. The adhesive includes deionized water, melamine-formaldehyde resin, modified aluminum hydroxide, organosilicon flexibility agent, and coupling agent. The modified aluminum hydroxide is prepared by reacting a functional modifier, N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine with benzophenone derivatives and pyridylthiazole derivatives, with 3-chloropropyltriethoxysilane and grafted onto aluminum hydroxide. The organosilicon flexibility agent is prepared by modifying phenyl hydrogen-containing silicone oil with allyl polyoxyethylene ether and glycidyl methacrylate. This invention achieves an integrated structure of the panel, maintaining a surface free of blistering and cracking under complex environmental conditions, with the overall material intact and without delamination, and possessing good antibacterial, fire-resistant, and UV-resistant properties.

The application discloses a preparation method and application of a chitin / melamine formaldehyde resin crosslinked hydrogel. The chitin / melamine formaldehyde resin crosslinked hydrogel is prepared by using chitin as a main raw material and by compounding the chitin with melamine formaldehyde resin, a thermosetting material with adsorption, and by adopting a chemical-physical double-crosslinking synthesis strategy and by regulating the mass ratio of the chitin and the melamine formaldehyde resin. The chitin / melamine formaldehyde resin composite hydrogel with an interpenetrating network structure is successfully prepared. The obtained hydrogel has excellent mechanical properties, adsorption properties and stability. After 48 hours of adsorption, the concentration of Zn 2+ and Ag + metal ions in acetonitrile is reduced to below 10 ppb, meeting the recovery requirements of high-purity acetonitrile. The raw material of the application is green and low in cost, and the preparation process is simple, so that the application provides an efficient solution for the adsorption of trace metals in organic solvents.

This invention relates to the field of glass coating technology, specifically to a self-cleaning coating for glass surfaces and its preparation method. The self-cleaning coating comprises the following components by weight: 3-7 parts of KH570-SiO₂ / photochromic microcapsules, 2-4 parts of fluoroalkylated silica, 25-35 parts of modified waterborne fluoroalkylsiloxane, 35-50 parts of deionized water, 0.5-2 parts of additives, 0.1-0.3 parts of leveling agent, and 0.2-0.3 parts of UV absorber; the additives are a combination of dispersant and thickener in a mass ratio of (70-85):(15-30). The core material of the photochromic microcapsules is a spiropyran compound, and the wall material is melamine-formaldehyde resin. It not only achieves self-cleaning but also provides anti-glare properties, making it widely applicable.

The application discloses a TiO2-foam carbon composite wave-absorbing material and a preparation method and application thereof, and comprises the following steps: performing a hydroxymethylation reaction on melamine and a formaldehyde aqueous solution under alkaline conditions to obtain a melamine-formaldehyde resin prepolymer solution; adding dropwise di(acetylacetonyl) titanium diisopropyl titanate and stirring to react to obtain a titanium-doped colloid; adding a non-ionic surfactant, a physical foaming agent and a curing agent, and then performing shear homogenization treatment to obtain a foaming slurry; performing step-by-step curing to obtain a titanium-doped organic foam block; and performing carbonization and crushing to obtain the TiO2-foam carbon composite wave-absorbing material. The wave-absorbing material effectively utilizes the dielectric loss capacity of TiO2 and the electric conduction loss characteristics of foam carbon, and further introduces a large number of heterogeneous interfaces, pore structures and defects, so that the interface polarization, multiple scattering and dipole polarization effects are enhanced, and the impedance matching and electromagnetic wave loss capacity of the material are improved.

This invention provides a flexible functional composite material with excellent thermal management capabilities and its preparation method. It mainly comprises the following key components: a polydimethylsilane (PDMS) matrix material, a hexagonal boron nitride (h-BN) thermally conductive material, and a microencapsulated phase change microsphere (MPCM) thermal storage material with melamine-formaldehyde resin as the shell and n-eicosane as the core material. The preparation method involves only simple stirring, heating, and curing, and based on the crosslinking inhibition mechanism and external force constraints, it is possible to prepare flexible functional composite materials with high filler concentrations. The flexible functional composite material of this invention exhibits excellent mechanical and thermal management properties. The thermally conductive phase material can rapidly transfer heat flow, improving the heat absorption efficiency of the thermal storage phase material, while the thermal storage phase material can rapidly absorb heat, promoting temperature reduction. This invention is simple to prepare and has superior performance, showing promising application prospects in fields such as electronic skin, electronic devices, and advanced fabrics.

The present application relates to the technical field of porous reservoir materials, and discloses a perfume porous reservoir material with a biomimetic honeycomb structure and a preparation process thereof, modified melamine formaldehyde resin, hollow glass microspheres, mesoporous silica nanoparticles, natural plant polyphenol, nano-hydroxyapatite, biodegradable polyester resin, a surfactant mixture, and a catalyst. The modified melamine formaldehyde resin is used as a skeleton material, the hollow glass microspheres and the mesoporous silica nanoparticles are introduced as composite fillers, and the natural plant polyphenol is added as a functional modifier to form a unique three-dimensional network structure. The skeleton material provides structural support and mechanical strength to ensure the integrity of the material during use. The functional filler provides a high specific surface area and porosity to achieve efficient adsorption and storage of perfume. By constructing a multi-level pore structure system and combining the principles of biomimetics, efficient storage and sustained controllable release of perfume are achieved.

The present application belongs to the technical field of papermaking and functional material composite, and in particular relates to a decorative paper with antibacterial function and a preparation process thereof. The present application discloses a scheme named "a decorative paper with antibacterial function and a preparation process thereof", aiming to solve the problems of uneven dispersion, uncontrollable release and poor antibacterial durability of existing antibacterial agents in decorative paper. The decorative paper comprises a decorative base paper layer, an embedded antibacterial functional layer and a surface cross-linked protective layer; wherein the embedded layer is composed of amino-modified mesoporous silica microspheres loaded with nano-zinc oxide / quaternary ammonium salt chitosan composite antibacterial agent and modified melamine formaldehyde resin, and presents a spatial gradient distribution; the surface layer is cross-linked and solidified by a silane coupling agent to form a dense protective film. The structure realizes the dual mechanism of humidity-responsive controlled release and contact sterilization, while ensuring the physical properties and appearance of the decorative paper, providing broad-spectrum and long-lasting antibacterial effect, with an antibacterial rate of ≥99.5% in 24 hours, and the antibacterial rate still >95% after 50 times of wiping or 12 months of aging.

This invention relates to the field of functional materials technology, and discloses an anti-Kasha organic long-afterglow material, its preparation method, and its applications. The anti-Kasha organic long-afterglow material provided by this invention precisely reconstructs the excited-state energy levels of guest molecules through a sulfur oxidation strategy. Using melamine-formaldehyde resin as a rigid matrix, a pure organic long-afterglow material system with both high quantum yield and anti-Kasha type multiple phosphorescence emission is successfully constructed. Compared with the unoxidized system, the singlet-triple bandgap of the oxidized molecules is significantly reduced from 1.264 eV to 0.944 eV, significantly enhancing the intersystem crossing efficiency. At the optimal doping concentration, a phosphorescence quantum yield of up to 63.1% and a total quantum yield of 88.5% are achieved. Furthermore, the oxidized molecules form a dense multi-triple energy level layout, effectively suppressing the internal conversion from the high-energy triplet state to the lowest triplet state in the rigid matrix. For the first time in this type of system, anti-Kasha type multiple room-temperature phosphorescence emission precisely tunable by the excitation wavelength is achieved.

The invention discloses fingerprint-resistant impregnated bond paper and a preparation method thereof, and belongs to the technical field of decorative materials. The method comprises the following steps: firstly, carrying out primary impregnation on decorative raw paper by using melamine modified urea resin, and then impregnating the decorative raw paper by using melamine formaldehyde resin modified by a fluorinated inorganic SiO2 core-Gemini organic shell core-shell structure, so as to prepare the fingerprint-resistant impregnated bond paper. The Gemini organic shell can improve the compatibility of fluorinated nano SiO2 and resin, particle aggregation is avoided, and meanwhile, a functional micro-area is driven to be enriched towards the surface layer by utilizing water-isopropanol volatilization gradient, so that a compact low-surface-energy anti-fingerprint layer is formed. The static water contact angle of the obtained adhesive film paper can reach 142 degrees, an excellent anti-fingerprint effect is still kept after 1000 times of dry wiping, and the durability is remarkably improved. The problems that traditional fluorine series modification is prone to agglomeration and fluorine components are prone to loss are solved, the process is stable and controllable, and the method is suitable for industrial production of anti-fingerprint ecological boards for high-end furniture and smart home panels.

The application discloses an anti-sticking modified BOPP master batch and a preparation process thereof, and particularly relates to the field of polypropylene film master batch. The preparation process of the master batch comprises the following core steps: firstly, a mixture of aluminum stearate and calcium stearate is reacted with a modifier such as vinyl silane at a certain temperature to generate a modified compound. Secondly, polypropylene resin, a dispersing agent, the compound, a microcapsule foaming agent and an antioxidant are mixed according to a specific mass ratio to obtain a premix. The microcapsule foaming agent is prepared by in-situ coating of azodicarbonamide with melamine-formaldehyde resin, and finally, the premix is subjected to melt blending, extrusion and granulation in a double-screw extruder at a set temperature, melt pressure and screw rotation speed to obtain a final master batch product. When the master batch is used for BOPP film production, it can be blended with base polypropylene in proportion, and then subjected to melt extrusion and bidirectional stretching to form a film with excellent anti-sticking performance.

The utility model discloses a kind of concrete blocks combined with microcapsule phase change material, it is related to concrete block technical field, the concrete block includes block main body, the top of the block main body is equidistantly provided with multiple positioning blocks, the bottom of the block main body is equidistantly provided with multiple positioning grooves, and positioning groove and positioning block are adapted between, and the block main body includes microcapsule phase change material main body.In the utility model, the microcapsule phase change material main body of block built-in, its kernel paraffin-fatty acid composite phase change material can be in 20~28 ℃ interval high-efficiency heat absorption and release, reduce indoor maximum temperature 2~5 ℃ in summer, reduce heat loss 15~25% in winter, realize building energy saving and indoor thermal comfort promotion, shell melamine-formaldehyde resin can completely block phase change material leakage, guarantee the stable temperature control life of block more than 15 years, avoid the functional attenuation caused by material loss of conventional phase change block.

The application discloses high-wear-resistance melamine impregnated decorative paper and a preparation method thereof, and belongs to the technical field of decorative materials. The preparation method comprises the following steps: S1, preheating and argon / oxygen low-temperature plasma treatment of raw paper; S2, impregnation of modified melamine formaldehyde resin and pre-drying to semi-curing; S3, spraying of KH-560 ethanol solution on the surface of the semi-curing layer to form an interface bonding layer; S4-S6, preparation of first, second and third wear-resistant layer coating liquids respectively, and gradient coating of the three layers of coating liquids on the interface bonding layer in sequence, and pre-drying and drying are performed to obtain the high-wear-resistance melamine impregnated decorative paper. Through the synergistic effect of the modified resin, the interface chemical bonding and the three-layer gradient wear-resistant layer, the wear resistance of the decorative paper is significantly improved, meanwhile, the decorative paper has good crack resistance, impact resistance and crack resistance, and can be widely applied to high-wear-resistance requirement fields such as reinforced wood floor, furniture veneer and cabinet board.

The utility model provides an anti-tear folding impregnated paper, including the base material layer, fiber reinforced layer, impregnated layer, surface protection layer connected in proper order, the base material layer is biaxially oriented polypropylene film, fiber reinforced layer is polyester fiber grid, is fixed on the base material layer through hot melt adhesive point -like adhesion, the impregnated layer is the modified glue solution of melamine -formaldehyde resin and nanometer silicon dioxide compound, and the surface protection layer is poly (vinylidene fluoride) coating. The product has the advantages of preventing crack propagation; the high modulus of biaxially oriented polypropylene base material resists tearing force, and the tearing strength is improved in cooperation.

This invention relates to the field of coating technology, specifically to an aluminum cap coil coating and its preparation method. It achieves rapid curing at 245℃ / 1min by compounding saturated polyester resin A and saturated polyester resin B, combined with a dual crosslinking system of blocked isocyanate curing agent and n-butyl etherified melamine-formaldehyde resin, while maintaining good flexibility and resistance to boiling. Resin A provides moderate crosslinking activity, while resin B retains flexible segments; the two work synergistically to avoid brittleness caused by high crosslinking density. The melamine resin and isocyanate form a complementary crosslinking network, further improving the coating's resistance to damp heat. The addition of calcium sulfate whiskers significantly enhances the coating's flexibility and MEK resistance. This invention overcomes the inherent contradiction between rapid curing and high flexibility in coil coatings through a synergistic design of chemical crosslinking and physical toughening, while simultaneously meeting the stringent requirements of deep drawing and high-temperature boiling of aluminum caps.

This invention discloses a phosphorus-nitrogen flame retardant and its preparation method, belonging to the field of phosphorus-nitrogen flame retardants. It comprises: 1 part by mass of ammonium polyphosphate, with a mass ratio of ammonium polyphosphate to melamine of 5-15:1, and a molar ratio of melamine to formaldehyde of 1:2-3. The preparation is achieved through the following steps: S1, ammonium polyphosphate and solvent form a uniform ammonium polyphosphate suspension; S2, melamine and formaldehyde react in a 5wt%-15wt% ammonium polyphosphate suspension to generate a melamine-formaldehyde hydroxymethyl prepolymer; S3, the melamine-formaldehyde hydroxymethyl prepolymer reacts in the remaining ammonium polyphosphate suspension. This invention eliminates the adverse effects on the rate of expansion into char and the quality of the char layer by introducing APP into the MF coating layer. Furthermore, by using DMSO as a dispersant, it significantly improves the uniformity and density of the coating layer, effectively improving its flexibility and water resistance, thereby enhancing the flame retardant effect and processing stability of melamine-formaldehyde resin-coated ammonium polyphosphate.

This invention relates to the field of self-healing concrete technology, and more particularly to a crack-resistant self-healing concrete and its preparation method. The invention comprises the following components: 280-350 parts cement, 60-100 parts fly ash, 40-80 parts mineral powder, 15-30 parts silica fume, 700-850 parts fine aggregate, 1000-1200 parts coarse aggregate, 140-170 parts water, 4-8 parts water-reducing agent, 20-40 parts expansion agent, 8-20 parts self-healing microcapsules, 5-12 parts nano-silica, 1-3 parts polypropylene fiber, and 15-30 parts steel fiber. This invention uses melamine-formaldehyde resin as the wall material and epoxy resin as the core material. The resulting microcapsules have good mechanical strength and chemical stability, and a high core material coverage rate. When the width of concrete cracks reaches 0.1-0.3 mm, the microcapsules can effectively rupture and release the repair agent, achieving self-repair of the cracks. Furthermore, the synergistic effect of multiple functional components such as expansion agents, nano-silica, polypropylene fibers, and steel fibers forms a multi-level crack-resistant system, significantly improving the crack resistance of concrete and effectively extending the service life of concrete structures.