Development of an Advanced Process for Manufacturing Acetal Resins

An advanced process for manufacturing acetal resins has been developed. First, a new technology for the production of highly concentra ted aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mole of water per mole of formaldehyde, methylal oxidation gives only 1 mole of water for every 3moles of formaldehyde. Thus, industrially, the products of the methylal oxidation is more than 70% concentrated aqueous formaldehyde compared with 55% concentration from methanol oxidation. Secondly, with the highly purified formaldehyde from the concentrated aqueous formaldehyde, an end-capped polymer can be obtained using acetic anhydride as a chain-transfer agent or an end-capping agent during polymerization. Thirdly, the relatively high concentr ation of formaldehyde enhances the formation of 1, 3, 5-trioxane. Purified trioxane is copolymerized with ethylene oxide in the presence of an end-capping agent to get an end-capped polymer with high thermal stability. Two new intermediates in the initiation reaction of the copolymer ization, 1, 3, 5, 7-tetraoxacyclononane (TOCN) and 1, 3, 5, 7, 10-pentaoxacyclododecane (POCD), were isolated and a new initiation mechanism was proposed. Finally, the world's first acet al block copolymer was industrialized by the copolymerization of formaldhyde with lubricant functional polymer which has an active hydrogen atom. This acetal block copolymer exhibits excellent lubrication properties.