Do you need to protect products from rats? If so, there is an important new tool to add to your specifications arsenal.

PolyOne, a plastics compounder based in Avon Lake, Ohio, is offering a product called OnCap, an anti-termite/anti-rodent additive concentrate. It provides an alternative to metallic armor, glass roving, or special engineering polymers such as polyamide 12, which are often adopted to protect cables from hostile animal or insect environments.

C-Tech, an Indian company that developed the additive technology, says its material is non-toxic. C-Tech will not disclose the active ingredients, however. The most officials will say is that they are based on essential oils.

Christian Gustin, wire and cable product manager for PolyOne Color and Additives Europe, told Design News in an email interview: "We have conducted several field tests with cables jacketed with additive-containing compounds, and placed the cables in rodent-infested and termite-infested areas. These were not lab tests. Multiple trials concluded the formulas were effective in repelling both termites and rodents."

Rats can be a big problem because they are attracted to the smell, color, and texture of plastics. They particularly enjoy the plasticizers that are used to make wire and cable flexible, according to a technical paper delivered recently by Rishali Chaplot, assistant business development manager at C-Tech Corp.

According to British press accounts, rats chewing through power cables have been the cause of significant train delays in London. An article in The New York Times documented the damage rats can do to engine wiring, particularly during the winter months. Chaplot says rats have eaten through gas pipes in England, causing fatal explosions.

The plastic compounds developed by PolyOne using the C-Tech technology work in various ways to protect plastic products from insects and rodents. "Rodrepel" uses smell as a deterrent. Chewing is also discouraged by dermal irritation caused by the active ingredient. The compounds also have an extremely bitter taste, says Chaplot.

Field testing to determine the effectiveness of the chemicals was conducted at the Indian Institute of Chemical Technology, Hyderabad, India. Scientists there set up a large enclosure with at least five rodents for 30 days. Cables with and without the additive were buried in the enclosure. The average weight loss for the sample without the additive was extremely high compared to the average weight loss for the samples containing the additive.

The cost of the additive was not disclosed, but the amount required in a compound is reasonable. "Letdown ratio is different for each type," says Gustin. Masterbatches contain 5 percent of the additive. Compounds for anti-rodent need 3 percent loading and compounds for anti-termite require 1.5 percent loading.

C-Tech says the additives can remain effective for up to 40 years.

Non-toxic solutions are increasingly required in many countries, where additives such as lindane, pyrethroids, copper naphthenate, and other substances are either banned or are being replaced. PolyOne says the active substance is non-hygroscopic, does not migrate within the polymer, and resists leaching under typical application conditions.