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1859results about "Aldehyde/ketone condensation polymer adhesives" patented technology

Method of preparing alkali lignin modified phenolic resin

A method for preparing alkali lignin modified phenol-formaldehyde resin comprises the following steps: phenol, a first batch of formaldehyde solution, alkali lignin, metal oxide and dilution water are added into a reactor; a second batch of formaldehyde solution is added into the reactor; and a third batch of formaldehyde solution and a first batch of alkaline solution are added, formaldehyde trapping agent and a second batch of alkaline solution are added, and then material is discharged after cooling. The invention adopts the copolymerization technique to prepare an alkali lignin phenol formaldehyde adhesive, lignin and the phenol are added simultaneously, obtained hydroxymethylated lignin is reacted with hydroxymethyl phenol, a small part of the obtained hydroxymethylated lignin participates in the polycondensation of the hydroxymethyl phenol to form a main chain, and a large part of the obtained hydroxymethylated lignin forms branch chains through graft copolymerization, therefore, the lignin is introduced into a molecular chain and the aim of modifying phenol-formaldehyde resin is achieved. The invention can replace the use of 30-50 percent of the phenol, realizes stable and easy reaction control and easy industrial production; the bonding strength satisfies the requirements of national I-level plates; formaldehyde release reaches E0 level; therefore, the invention provides a new approach to the development of environment-friendly biomass-based wood adhesive and resource utilization of waste materials.
Owner:INST OF CHEM IND OF FOREST PROD CHINESE ACAD OF FORESTRY

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

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

Melamine-urea-formaldehyde copolycondensation resin (MUF) wood adhesive and preparing method thereof

The invention relates to a melamine-urea-formaldehyde copolycondensation resin (MUF) wood adhesive and a preparation method thereof, and belongs to the technical field of wood processing and production. The adhesive is formed through the copolycondensation of melamine (M), urea (U), formaldehyde (F) and amino-terminated hyperbranched polymer PAMAM, and is mainly characterized in that the formaldehyde and melamine are added at one step, urea is added at different times, PAMAM is added at the initial synthesis stage of the MUF resin. The MUF resin related to the invention belongs to resin with high content of melamine, the melamine accounts for 45% above the total amount of urea and melamine, wherein the formaldehyde and urea added for the first time are added at the initial reaction stage at one step, and then the PAMAM is added; after the urea added for the first time is added, the molar ratio of formaldehyde to urea is controlled above 3.0; the melamine is added at the middle and later alkaline stage; urea added for the second time is added at the later reaction stage. The melamine-urea-formaldehyde copolycondensation resin wood adhesive provided by the invention has the remarkable characteristics that the stability and performance are good, more importantly, and the storage period is long (lasting for longer than 5 months), and the adhesive can be applied to production of artificial boards, especially high hydrolytic-resistance artificial boards and laminated wood, and the like.
Owner:SOUTHWEST FORESTRY UNIVERSITY

Environmental-friendly urea-formaldehyde resin adhesive and production method thereof

The invention discloses an environmental-friendly urea-formaldehyde resin adhesive and a production method thereof. The production method comprises the following steps: lowering the traditional mol ratio (F/U) of the formaldehyde to urea into 0.94-1.0 from not less than 1.0; keeping the mol ratio basically unchanged after feeding the urea for the first time and the second time in the traditional process, increasing the urea amount for the third time, and adding a compound adjuvant which accounts for 0.1%-0.3% of the weight of the urea-formaldehyde resin adhesive for producing synergistic effect; in the acidic polycondensation stage, observing until a white vaporous shape appears in water at 40-45 DEG C by a muddy point method; and adjusting the pH value of a reactant into 6.5 from a traditional value of 7.5 so that the added urea for the second time can continuously participate in reaction, then observing until a white vaporous shape appears in water at 60-65 DEG C by the muddy point method for the second time, and finally ending reaction. The production method can obviously lower formaldehyde release of an artificial board and product cost of the adhesive, and ensure product quality of the urea-formaldehyde resin adhesive and physical and mechanical properties of the artificial board.
Owner:南宁市火炬新产品开发有限责任公司
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