Ask Chemicals Gmbh

Sritama Kar

Christian Priebe

Xianping Wang

Joerg Kroker

A release agent is disclosed for use with an organic binder system used in metal casting. The binder system has a Part I component including an epoxy resin and a free radical initiator and a Part II component having an epoxy resin and an acrylate, where the Part I and Part II components are kept separate until the time of use. The release agent will typically have a molecular weight in the range of 150 to 160, with eight to ten carbon atoms. Two examples of the epoxide are pinene oxide and decene-1 oxide, each of which is effective as an internal release agent when present in the binder for a cold box process in the range of about 0.15% to about 1% of the total weight of the Part I and Part II components.

Mold release agent for metal casting, containing pinene epoxide and/or decene-1 oxide

A no bake process is provided for preparing a foundry shape. A major amount of an appropriate foundry aggregate, especially a sand that has been mechanically-reclaimed, is mixed with an amount of halloysite tubes. A binder system, especially a water-based binder, such as an aqueous alkaline phenolic resole resin, is added to the mixed aggregate and halloysite, and a liquid co-reactant for curing the binder is also added. By intimately mixing the components, a foundry molding compound is formed and it can be placed into a mold or patter to cure into a foundry shape. When removed from the mold or pattern, the foundry shape can be used to cast molten metal.

Halloysite tubes in ester-cured phenolic bonded foundry shapes

Casting of non-ferrous metals, especially aluminum and magnesium, can have problems with erosion, in which molten metal contacts the mold or core surfaces during the pouring process, resulting in the sand being dislodged. Binder systems addressing this issue often use bisphenol F epoxy resin. A binder system is provided in which a major portion of the epoxy resin component is a bisphenol epoxy resin that has been modified by incorporating oxazolidone rings into an epoxy backbone of the bisphenol epoxy resin, especially a bisphenol A epoxy resin. The modification is preferably achieved by reacting the diglycidyl ether of the bisphenol with a methylene diphenyl diisocyanate.

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Sritama Kar