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3072 results about "Urea-formaldehyde" patented technology

Urea-formaldehyde (UF), also known as urea-methanal, so named for its common synthesis pathway and overall structure, is a non-transparent thermosetting resin or polymer. It is produced from urea and formaldehyde. These resins are used in adhesives, finishes, particle board, medium-density fibreboard (MDF), and molded objects.

Process for the manufacturing of an improved core for decorative laminates and a decorative laminate obtained by the process

A process for the manufacturing of a core forming a carrying structure for decorative laminates. The core comprises particles of cured, and optionally foamed, rigid, polyurethane, polyisocyanurate and / or phenolic resin. The particles are bonded to each other in a pressing procedure with a bonding agent comprising an adhesive such as a polymerizing monomer.i) The particles are achieved by grinding cured, and optionally foamed, rigid, polyurethane, polyisocyanurate and / or phenolic resin so that it passes through a 2 mm screen, preferably a 1 mm screen,ii) 100 parts per weight of particles is mixed with 1-100 parts per weight of fiber, the fiber additive having an average length in the range 1-15 mm.iii) The particle-fiber mixture is allowed to absorb a selected amount of water, the amount of water being in the range 1-15% by weight, The water is either added at any stage before the adding of bonding agent, and / or being used as a solvent in the bonding agent, and that,iv) 85 parts per weight of the particle mixture is mixed with 2-15 parts per weight of a bonding agent, the bonding agent selected from the group consisting of,a) A mixture of polyols, such as polyester or polyether, crude methylene diphenyl diisocyanate and possibly a small amount of blowing agent in a ratio forming a polymeric resin with a density in the range 600-1400 kg / m3.b) A formaldehyde based resin such as phenol-formaldehyde resin, urea-formaldehyde resin, melamine-urea-formaldehyde resin, melamine-urea-phenol-formaldehyde resin or phenol-resorcinol-formaldehyde resin, orc) Polyvinyl acetate resin.v)The mixture is applied between the belts of the continuos belt press or the press plates of a static press, optionally with at least one intermediate carrier web, the belts or press plates allowing a mainly uniform and specified material thickness to form. A slightly porous and preconditioned core with a selected water content in the range 0.8-12% is hereby achieved. The invention also relates to a decorative laminate achieved through the process.
Owner:PERGO

Environmental protection urea-formaldehyde resin and preparation method thereof

A novel environmental protective urea-formaldehyde resin and a preparation method belong to the field of wood processing adhesives. The urea-formaldehyde resin is formed by the reaction of urea, formaldehyde, aldehyde, one or more stabilizers and modifier according to the route of weak base-weak acid-weak base. The method firstly controls the F / U feed ratio, the pH value and the temperature during the reaction process to reduce the content of free formaldehyde in the resin; then the aldehyde is introduced to allow the resin to generate the stable alkyl ether (-(CH2)n-O-(CH2)n-) structure, thus reducing the content of methylene-ether bond (-CH2-O-CH2-) in the resin structure, simultaneously reducing the using amount of the formaldehyde and further greatly reducing the release amount of the formaldehyde during the using process of a plate from the two aspects; in addition, the introduction of a long chain and polyaldehyde can ensure the resin to have great bonding strength and water resistance. The urea-formaldehyde resin which is prepared by the invention has the advantages of low content of free formaldehyde, simple process, low cost, etc., the release amount of the formaldehyde of the plate which is prepared by using the adhesive achieves the E0 level standard, and the high bonding strength can be maintained after being boiled in hot water.
Owner:BEIJING UNIV OF CHEM TECH

E0-grade melamine modified urea-formaldehyde resin adhesive, and preparation method and application thereof

The invention relates to an E0-grade melamine modified urea-formaldehyde resin adhesive, and a preparation method and application thereof. The E0-grade melamine modified urea-formaldehyde resin adhesive is characterized by comprising an E0-grade melamine modified urea-formaldehyde resin, a composite curing agent and a composite filler, wherein the E0-grade melamine modified urea-formaldehyde resin is prepared from the following raw materials in parts by mass: 100 parts of formaldehyde, 0.1-0.5 part of polyvinyl alcohol, 100-200ml of basic catalyst and 200-400ml of acidic catalyst; the mol ratio of the formaldehyde to the urea+melamine (F / (U+M)) is equal to 0.80-0.98; the composite curing agent is prepared from the following raw materials in parts by mass: 200-250 parts of ammonium chloride, 150-200 parts of oxalic acid, 400-450 parts of citric acid, 100-150 parts of tartaric acid and 500-800 parts of water; and the composite filler is prepared from the following raw materials in parts by mass: 60 parts of industrial flour, 20 parts of 800-mesh light calcium carbonate and 20 parts of 800-mesh wood meal. The E0-grade melamine modified urea-formaldehyde resin adhesive is used for gluing plates. The E0-grade melamine modified urea-formaldehyde resin adhesive has the advantages of low free formaldehyde content, low cost, favorable precompression performance, good gluing performance and the like.
Owner:BEIHUA UNIV

Production method of environmental-friendly type low-cost middle and high density fiber board

The invention relates to a production method of an environmental-friendly type low-cost middle and high density fiber board. Self-made modified urea-formaldehyde glue, a composite curing agent and a formaldehyde trapping agent are used in a glue blending procedure, wherein the modified urea-formaldehyde glue is prepared by heating formaldehyde, melamine and urea in a reaction kettle through a chemical reaction; the composite curing agent is prepared by mixing ammonium chloride, boric acid, oxalic acid and water; and the formaldehyde trapping agent is prepared from phosphoric acid, urea, a catalyst and water under a certain temperature condition. When the middle and high density fiber is produced, the application amount of the formaldehyde trapping agent is 3 percent or 4 percent of the weight of modified urea-formaldehyde glue solid, the application amount of the modified urea-formaldehyde glue solution is 12.5 percent of the weight of absolute dried fiber, and the application amount of the composite curing agent is 3 percent or 2 percent of the weight of the modified urea-formaldehyde glue solution. The middle and high density fiber board produced using the three ingredients can completely meet Eo level environmental-friendly requirements, has good compatibility and high bonding strength and greatly reduces production cost of the fiber board.
Owner:ZHEJIANG FORESTRY ACAD +1

Urea-formaldehyde resin coated epoxy acrylic resin microcapsule for resin-base self-repair coating and preparation method thereof

The invention relates to a urea-formaldehyde resin coated epoxy acrylic resin microcapsule for a resin-base self-repair coating and a preparation method thereof. The preparation method is characterized by comprising the following steps: adding capsule core raw materials epoxy acrylic resin and acrylate reactive diluent into a water solution containing an emulsifier and a defoaming agent, dispersing the capsule core with a homogenizer or emulsifying machine to form a stable emulsion; regulating the pH value of the stable emulsion system to 2-3, adding capsule wall raw materials urea, formaldehyde and crosslinking agent, stirring until the capsule is formed, and after the reaction finishes, regulating the pH value of the system to neutral; and repeatedly washing with hot water and acetone, centrifuging, and carrying out vacuum drying to obtain the epoxy acrylic resin microcapsule. The capsule provided by the invention has the advantages of favorable sealability, regular sphericity, controllable grain size and controllable capsule wall thickness, and can be widely used for self-repair of a UV-cured acrylic resin coating or epoxy resin coating at low temperature and room temperature, thereby prolonging the service life of the coating material and widening the application range of the resin-base coating.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Industrial production method and device of urea-formaldehyde slow-release compound fertilizer

The invention relates to an industrial production method and device of a urea-formaldehyde slow-release compound fertilizer and a device thereof. The industrial production method comprises the steps of adding water and oxidized starch to a reaction still and then pasting, adding urea of which the nitrogen content is 46wt% and formalin, stirring, dissolving and then adjusting the pH value to 8.5-8.8 by an alkaline matter, reacting at constant temperature of 60 DEG C to obtain reaction liquid; adjusting the pH value to 5.4-5.1 by the reaction liquid; reacting for 45 minutes at the constant temperature of 65-68 DEG C, then adjusting the pH value to 6.8-7.2, and terminating reaction to obtain the urea formaldehyde condensation product solution; mixing the urea formaldehyde condensation product solution with nitrogen, phosphorus and potassium materials, pelletizing, drying and cooling to below 35 DEG C, and screening to obtain the urea-formaldehyde slow-release compound fertilizer. The industrial production device of the urea-formaldehyde slow-release compound fertilizer is also provided by the invention. Urea formaldehyde is taken as a skeleton; rapid disintegration phenomenon of fertilizer particles caused by water absorption expansion is effectively prevented; the urea-formaldehyde slow-release compound fertilizer has good nutrient slow-release performance, and is high in pelletizing rate in the production process and strong in granule hardness, and the total nutrient content is improved.
Owner:河南豫邮金大地科技服务有限公司

Modified lignin and urea-formaldehyde resin synthesized from same and preparation methods of modified lignin and urea-formaldehyde resin

The invention discloses a modified lignin and a urea-formaldehyde resin synthesized from same and preparation methods of the modified lignin and the urea-formaldehyde resin, belonging to the field of bonding agents used in wood processing. A technological synthetic route with weak base-weak acid-weak base is adopted, the molar ratio of formaldehyde to urea is controlled during an addition stage to generate a reasonable structure, the modified lignin as well as residual hydroxymethyl and free formaldehyde are added at the later stage of reaction in order to accomplish reaction, thus the content of methylene ether link (-CH2-O-CH2-) and the content of hydroxymethyl in the resin are reduced to a certain extent, the formaldehyde emission of the resin is lowered, and simultaneously, higher bonding strength and water resistance are ensured. The urea-formaldehyde resin in the invention is simple and brief in process and low in cost, the formaldehyde emission of the plate prepared by adoptingthe bonding agent reaches the E0-level standard and the plate can maintain high bonding strength after being cooked in hot water. The modified lignin is simple in synthesis method and low in cost andis especially suitable for the modification of the urea-formaldehyde resin with low molar ratio.
Owner:BEIJING UNIV OF CHEM TECH
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