In his March 2008 column, Dr. Dave discusses adhesives produced from latex concentrate and adhesives used for the bonding of precast metal pan stairs.

Question:Our company produces latex concentrate in Malaysia. We intend to diversify our business line into adhesives, but what kind of adhesive can one produce from latex concentrate?

Answer:Because of its high tack, natural latex has been traditionally used for contact adhesives and in pressure-sensitive adhesives. There is a good opportunity for you to look at the contact adhesive market, because it is one that has traditionally used polychloroprene-based adhesives. Polychloroprene is a very high-priced elastomer and has been in short supply in recent years. Pressure-sensitive adhesives use has been growing rapidly in labeling and tape production, and this should give you a potentially large market. In view of the allergy issues associated with natural latex in gloves, it is encouraging to see that producers are looking for alternative markets where this should not be an issue.

Question:I have a typical metal pan stair, except the front edge of the pan is open, not closed. In lieu of filling the pan with concrete, we are using a precast concrete tread. I need an adhesive that will bond the precast stair. Do you have any suggestions?

Answer:I would suggest that you look at both epoxy adhesives and polyurethanes. Epoxies have been used for many years in bonding and coating pre-cast concrete, and they have a great track record in adhering to both dry and wet concrete. Two-part polyurethanes will also work well and will give you a somewhat more flexible bond. Please ensure that the concrete is fully cured before using the polyurethane in order to avoid large amounts of water that might cause excessive foaming or bond delamination.