Production formula for urea-formaldehyde resin adhesive

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1. Purpose: This adhesive is made by mixing urea, formaldehyde, urethane, and other ingredients, and it is specifically used for bonding wooden materials such as particle board and plywood. At the same time, it also has a strong bonding effect on bonded bamboo products and furniture. 2. Raw materials (1) Urea: also known as carbamide. Colorless crystals. It is present in large quantities in the urine of humans and mammals. Soluble in water, ethanol, and benzene; practically insoluble in ether and chloroform. The aqueous solution is almost neutral. Used in industries such as fertilizers, **, etc. It is used as a raw material for preparing polycondensates in this product. Choose industrial products. (2) Formaldehyde: colorless gas. It has a particularly pungent odor that irritates the eyes, nose, and other parts of the body. Soluble in water and ethanol. The concentration of the aqueous solution can reach up to 55%, with a typical value of 44%; it is known as formalin solution, commonly referred to as formalin. It has a strong reducing effect, especially in alkaline solutions. It is used as a raw material for preparing polycondensates in this product. Choose industrial products. (3) Urotropine: the scientific name is hexamethylenetetramine. White crystalline powder or colorless, shiny crystals. Almost odorless, soluble in water, acetone, ethanol, and chloroform, insoluble in ether. It is used as a curing agent for resins and plastics, as a vulcanization accelerator for rubber, and as an anti-shrinking agent for textiles; it is also employed in the production of drugs, fungicides, and more. Choose industrial products. (4) Sodium hydroxide: also known as caustic soda or lye. A white solid, appearing in granular, flaky, rod-shaped, or lump form. It is a strong base, and it is highly corrosive to skin, fabrics, paper, etc. It has strong hygroscopicity, and it easily absorbs moisture and carbon dioxide from the air to gradually turn into sodium carbonate. It is soluble in water and releases a large amount of heat; it is widely used in the papermaking, rayon, dyeing, soap, petroleum, and other chemical industries. It is used as a pH regulator in this product. (5) Ammonia water: An aqueous solution formed by dissolving gaseous ammonia in water. Ammonia is highly volatile and escapes easily, which gives it a strong, irritating ammonia smell. It is weakly alkaline. It is generally referred to as an ammonium hydroxide (NH4OH) solution. The strongest ammonia solution contains 35.28% ammonia. It is mainly used as a liquid fertilizer. It is used as a pH regulator in this formulation. Choose industrial products. (6) Hydrochloric acid: also known as hydrogen chloride, an aqueous solution of hydrogen chloride. Pure hydrochloric acid is colorless, while industrial grades appear yellow due to impurities. The product is an aqueous solution of hydrogen chloride at a concentration of 37%. It is used as a pH regulator in this formulation. 37% industrial products are selected. (7) Ammonium chloride: commonly known as nitre. A white crystal that is hygroscopic; soluble in water and glycerin, slightly soluble in ethanol; used medically as an expectorant. It is used as a curing agent in this product. Choose industrial products. 3. Formula (by weight): Urea 100, Formaldehyde (37%) 372, Ammonia water (28%) 40, Ammonium chloride 18, Sodium hydroxide (10%) 0.5, Urotropin 5.2, Hydrochloric acid (15%) 0.5. 4. Preparation method: (1) Add formaldehyde and urotropin to the reaction vessel; heat to 30°C while stirring, then add ammonia water to adjust the pH to around 8, continuing to stir. (2) Urine yarn is added under stirring, the temperature is raised to 90°C, then the pH value is adjusted to 5–6 using hydrochloric acid, and the mixture is allowed to reflux for 30 minutes. After the viscosity test shows it is satisfactory, it is neutralized with sodium hydroxide solution to a pH of 7–8; upon cooling, the final product is obtained. 5. Usage Method: When using this agent, a curing agent must be added. Common curing agents include ammonium salts such as ammonium chloride, with the dosage generally ranging from 0.1% to 1.0%. The more curing agent used, the higher the curing temperature, and the faster the curing speed. Conversely, it is slower. China Resin Online is striving to create the largest database in China’s resin industry! To overcome the problem of crack formation, fillers and plasticizers can be added during use, such as starch, wheat flour, soybean gum, casein polyvinyl acetate emulsion, polyvinyl alcohol, etc. The drawback of this agent is its instability in boiling water. This post was last edited by I’m quick on 2009-3-16 14:56]