An innovative micro-cellular polyurethane foam based system provides tires with a longer service life and lighter weight. It is a fact that flat tires hinder movement. It takes a considerable effort to move them and they are more difficult to steer. All sorts of external hazards also threaten the tires, such as nails, shards, broken glass, etc. If a wheelbarrow is out of use for a while, for instance, during winter, the first user will often find the tire flattened.
A British company Greentyre has launched tires that are prompt for use at all times and are not affected by sharp objects or long periods of inactivity. To manufacture the tires, the mold is filled with a liquid reaction mix before being rotated during the foaming process. This ensures that the material is distributed very evenly across the whole tire circumference, which means that the tires will run very smoothly. The rotational method for manufacturing tires creates a special integral skin foam structure in which the foam density increases towards the outside of the tire. While the microcellular PU foam is nearly solid at the tire's outer circumference, its even surface makes for enables brilliant rolling properties. Due to its good aging and weathering resistance, it retains its true-running properties in the long term. This resistance does not deter even when it remains in one position under a heavy load for an extended period of time and is compressed on one side. And the high elasticity of the micro-cellular Bayflex® material ensures that the tire's rolling resistance is almost as good as that of an air-filled tire.
The tires are made of microcellular polyurethane foam based on a Bayflex system from Bayer MaterialScience, and are more durable and much lighter than solid rubber tires. However, this tire technology is not just useful for leisure activities and gardening but also ideal for wheelchairs. The company has designed a very special wheelchair for disabled people. One key feature of the sophisticated design concept is its modular structure, which enables users to choose from an array of options to meet individual clinical need and, of course, a range of tires depending on the type of use. If required, the wheels can also be removed at the touch of a button. Additionally, the wheels are equipped with ergonomic handrims also made of polyurethane. The special feature of these handrims is that they do not get sharp edges through wear and are pleasantly warm to the touch. Lastly, the wheelchairs' adjustable armrests are also padded with this polyurethane foam and available with safety lamps as an option - another innovation.
Amerityre Corporation, another leading developer of polyurethane tire technologies and tire products, has embarked on commercial production of solid polyurethane elastomer tires. The tire technology would provide improvements in the durability and performance in agricultural equipments which are supplied globally. The company has developed a tire-wheel combination that would provide enough toughness to replace the steel gage wheels that have previously been used in their products. The company has also demonstrated the capability of making solid polyurethane elastomer forklift tires at the rate of a tire per minute. Other potential commercial applications for the solid polyurethane elastomer tires include forklift and aperture tires used in the construction and material handling industry. The two polyurethane tire technologies used include the ‘ Polyurethane Foam Technology' and ‘Polyurethane Elastomer (Elastothane TM ) Technology.' In the former, the company uses proprietary polyurethane chemical formulations to develop a high density, closed cell foam material that is superior in low speed foam tire and light weight tire fill applications. This foam material gives high abrasion resistance, excellent load carrying capability and longer life. Also, the material does not absorb water due to closed cell technology and high resistance to ozone and UV light. The technology creates materials which exhibit superior temperature, abrasion and elastic properties for use in tire fill, solid tire, composite tire and pneumatic tire applications. In addition to all the above properties, the materials made using the technology show better elastic properties, reduced operating temperatures, increased fuel economy due to lower rolling resistance. All in all, the elastomers are environment friendly as they possess no oils or plasticizers.
Polyurethane products have a number of uses with flexible and rigid variants of polyurethane taking up nearly 75% out of the all the foam products. In both cases, the foam is usually behind other materials: flexible foams are behind upholstery fabrics in commercial and domestic furniture; rigid foams are inside the metal and plastic walls of most refrigerators and freezers, or behind paper, metals and other surface materials in the case of thermal insulation panels in the construction sector. Polyurethane is also used in making solid tires. The relatively recent advancements of polyurethane foam are in form of microcellular foam variants which have found applications in tires on wheelchairs, bicycles and other such uses. Also, microcellular polyurethane foams can be widely encountered in car steering wheels and other interior and exterior automotive parts, including bumpers and fenders.
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