Researchers at Oregon State University (OSU) have found that sugar is effective as a non-toxic, renewable binder material for sand moulds.
According to OSU, some technologies use various ‘binders’ to adhere sands and other materials to form moulds, into which molten metals are injected to create products with complex shapes.
Some materials used in the process, including furan resins and phenol formaldehyde resins, can emit toxic fumes during the procedure.
Experts in adhesion science in the OSU College of Forestry have applied for a patent on their use of sugar and other plant materials for this purpose.
In a statement, they said it should cost less than existing binders, is completely renewable and should be environmentally benign.
‘We were surprised that simple sugar could bind sand together so strongly,’ said Kaichang Li, an OSU professor of wood science and engineering. ‘Sugar and other carbohydrates are abundant, inexpensive, food-grade materials.
‘The binder systems we’ve developed should be much less expensive than existing sand binders and not have toxicity concerns,’ Li added.
Sugar is a highly water-soluble food ingredient but the OSU researchers are said to have discovered a novel way to make strong and moisture-resistant sand moulds with the substance. An inaccurate reading of temperature in a baking oven helped lead to the discovery, they said.
Li and an OSU faculty research assistant, Jian Huang, identified combinations of sugar, soy flour and hydrolysed starch — or even just sugar by itself — that should work effectively as a binder in sand moulds for making various types of metal parts.
This novel sand-binder technology is ready for more applied research and testing, they said, and the university is seeking investors and industrial partners to commercialise it.
Sand-based mouldings comprise approximately 70 per cent of all metal castings and are a major part of the automobile industry; they also have applications in plumbing materials, mining and railroads.
Sugar and the other agricultural products used for this purpose should have no environmental drawbacks, since they largely decompose into carbon dioxide and water.
With the techniques developed at OSU, the use of sugar as a binder allows the creation of sand moulds that gain strength rapidly and remain strong in high-humidity environments, which is necessary for their effective use in industrial applications.
Li’s laboratory at OSU has developed other related products in recent years, such as a natural resin made from soy flour that is already being used commercially to replace the use of formaldehyde-based adhesives in the manufacture of some wood products.