Patent
Removal of free formaldehyde from urea resin particle dispersion
TLDR
In this article, the free formaldehyde is removed from a urea resin particle dispersion by adding sulfurous acid (salt) to the dispersion at a specified molar ratio to the free aldehyde contained therein, reacting them and adjusting the final pH to around a neutral value.Abstract:
PURPOSE:To remove free formaldehyde easily from a urea resin particle dispersion, by adding sulfurous acid (salt) to the dispersion at a specified molar ratio to the free formaldehyde contained therein, reacting them and adjusting the final pH to around a neutral value. CONSTITUTION:Formaldehyde is condensed with urea to form a urea resin particle dispersion containing free formaldehyde. To this dispersion, sulfurous acid (salt) (e.g., sodium sulfite or acid sodium sulfite) in an amount of 0.5-1.5mol per mol of the free aldehyde is added, and the reaction between them is effected. The final pH of this dispersion is adjusted to 5-9 in order to prevent the bisulfite compound as the reaction product from forming free formaldehyde by decomposition during storage. In this way, a urea resin particle dispersion containing no free formaldehyde can be obtained.read more
Citations
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Patent
Method for producing naphthalenesulfonic acid formaldehyde condensate
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TL;DR: In this article, a method for easily producing a naphthalenesulfonic acid formaldehyde condensate water-soluble salt which is decreased in the quantity of unreacted formaldehyde, produces a product stabilized in quality, and is reduced in the load to the environment, and thus is suitably applied to a cement dispersing agent is provided.
Patent
Detection method and detection device for content of formaldehyde in foods
TL;DR: In this article, a detection method and a detection device for the content of formaldehyde in foods are presented, in which a formaldehyde solution is added to the solution and the pH value of the solution rises, and the rising trend of the pH values is in direct proportion to the concentration of the formaldehyde.
Patent
Treatment method for formaldehyde wastewater
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References
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Patent
Production of amino resin containing less unreacted formaldehyde
Katsuo Ebisawa,Osamu Matsudaira +1 more
TL;DR: In this article, an amino-formaldehyde condensate is treated with aqyeous alkali sulfite to give an amino resin containing less unreated formaldehyde and having no odor and high-stability.