The first automatic lawnmower made by Husqvarna AB in Sweden liberates gardeners from the tedious, time-consuming chore of mowing lawns. To keep Auto-mowers continuously operating for years on end, engineers housed them in a highly weather-resistant acrylonitrile-styrene-acrylate (ASA) copolymer. The Luran S copolymer from BASF Corp., Florham Park, N.J., protects mower inner workings while retaining its dark-green shiny surface even after years of extreme heat and rain. "The lawnmower housing was originally a standard plastic coated with fade-resistant paint," explains BASF spokesperson Geoff Nelson. "The switch to UV-resistant Luran S eliminates painting so it's easier and more economical to manufacture the mowers."
A nonpainted body also better resists scratches, says Nelson. The ASA's good weather resistance comes from the addition of acrylate rubber and dark-green pigments that boost durability and colorfastness.
A close relationship between the Husqvarna team in the U.K. and BASF was key, says Gary Blenkinsopp, technical manager at Husqvarna (Aycliffe), a subsidiary of the Swedish electrical appliance manufacturer Electrolux. "BASF's help in optimizing the plastic's flowability convinced us to switch to Luran S Type 757G," he says. "The 757G blend is particularly easy flowing so relatively large, complex parts uniformly fill and exit the mold with high-quality finishes."
The programmable robot's plastic body measures 27.6 in. (70 cm) long and 23.6 in. (60 cm) wide. It acts as a collision sensor and protects the chassis that houses the electric motors, the PIN-coded electronic unit, an alarm system, and several sensors that detect demarcation wires that are placed along the perimeter of the lawn for guidance. The sensors can also recognize obstacles such as trees and pets.