Just as some lucky human beings have good DNA that predisposes them to good health, high performance and great longevity, so it is with some engineering thermoplastics that are supplanting metals in many applications.
Ultra High Molecular Weight Polyethylene UHMWPE
One of the thermoplastic family favourites from an engineering point of view is polyethylene, represented in the Dotmar EPP family by the Polystone range of ultra high molecular weight polyethylenes (UHMW-PE).
Properties of Ultra High Molecular Weight Polyethylene
These versatile thermoplastics feature unusually long molecular chains that serve to transfer load more effectively to the polymer’s backbone by strengthening intermolecular interactions. This results in one of the most durable thermoplastic polyethylenes on the market – and one that is odourless, non-toxic, tasteless and can offer considerable weight and cost savings compared with metal alternatives.
Applications of Ultra High Molecular Weight Polyethylene
Applications of Polystone UHMWPE cover a diverse spectrum of applications, including:
- Bulk material handling
- Food processing and beverage machinery
- Mining and mineral processing equipment
- Manufacturing equipment
- Civil engineering and earthmoving equipment
Transport-related applications, including truck trays, bins and hoppers.
Advantages of Polystone UHMWPE
While every thermoplastic stands out with one or two key benefits, Polystone possesses several. Advantages include:
- Excellent resistance to stress and high resistant to cracking (i.e. it has high tensile and compressive strength)
- High operational temperatures with a melting point of 160°C
- Excellent dielectric properties
- It is highly resistant to most alkalis and acid, organic solvents, degreasing agents and electrolytic attack. - Non-toxic
- Easy to produce, assembly and an economic material
When compared with traditional polymers, Polystone is the only thermoplastic that has the highest resistance to abrasion and chemical erosion, while at the same time maintaining product integrity under higher impact/stress situation.
Self-Lubricating and Non-Stick Properties
Additionally, the range’s self-lubricating character yields a non-stick surface comparable with PTFE. Put all these benefits together with low moisture absorption character and low coefficient of friction and you have the most durable plastic available anywhere - and ready to go into service just about anywhere.
Grades of Polystone UHMWPE
However, it is important for the engineer and designer to appreciate that no single product in the Polystone UHMW-PE family exhibits all of the desirable characteristics that a customer looks for in a polymer. In selecting the perfect Polystone for particular applications, it pays to know the difference between the major categories. These include:
- Polystone 7000
- Polystone Ultra
- Polystone 7000SR
- Polystone M Flametec
- Polystone Matrox
Polystone 7000 is the general purpose UHMWPE. It is suited to engineered applications where its unique properties of excellent impact strength, wear and abrasion resistance are required. Like other members of the Polystone family to follow, its key features and benefits include:
- Impact Strength - it is virtually unbreakable
- Light weight - easy to handle without special equipment
- Physiologically inert - approved for food applications
- Electrical insulation - it is a good insulator
- Weatherproof - it doesn't absorb water
- Chemical resistance - resists corrosive chemicals (Sulphuric Acid, Caustic Soda)
- Abrasion resistance - rated better than Carbon Steel for sliding abrasion applications
- Low coefficient of friction - it does not require lubrication
Polystone Ultra is specifically formulated for improved sliding characteristics, enhancing its resistance to wear, abrasion, and environmental stress cracking.
This material is ideally suited to flow promotion and mechanical transmission support products. Sharing the key advantages of general purpose UHMWPE, this material is engineered to deliver top performance in applications such as:
- Bulk storage flow promotion
- Bulk storage wear liners
- Mechanical chain guides
- Mechanical wear strips
Polystone Ultra not only reduces friction, wear, clogging and noise compared with metal, but also never needs lubrication.
Polystone 7000SR is specifically formulated to suit applications where reduced static is required in handling of bulk materials and other high speed sliding applications. These include lining of storage systems and change parts for the beverage industry. It is particularly suited to:
- Bulk storage flow promotion
- Bulk storage wear liners
- Grain industry
- Coal handling
Polystone M Flametec
Polystone M Flametec is the first flame retardant and anti static UHMWPE that has the following specialties:
- Halogen free
- Antimony free
- No strong smoke emission
- Non-toxic smokes/gases
- Technical properties of UHMWPE are not reduced
- Fire Rating - achieved UL94 class V0
Applications for which it is designed include underground mining, scraper blades, hopper liners, liner beds, wear profiles, impact slider blades and chain guides.
Polystone Matrox is a specially formulated premium grade UHMWPE. Its unique combination of properties includes outstanding abrasion resistance, excellent non-stick properties and excellent corrosion resistance.
Polystone Matrox is ideally suited for the lining of hoppers, bins and earth moving equipment to promote flow, reduce hang-up and carry-back.
This new premium grade polymer alloy liner is specifically designed for lining hoppers, chutes, bins, dump truck bodies, dozer blades and many other applications requiring solutions to sliding, abrasion and release of sticky, hard-to-move materials. Polystone Matrox delivers best-case production flow rates at optimum wall angle
Its formulation achieves an extremely low co-efficient of friction. Strict measurement of results during its development ensure an extremely high quality product for use in many demanding bulk solids handling industries, including mining, minerals and concentrate handling, quarrying, chemical, filtration, packaging, timber and marine engineering.
Engineers should consult appropriate technical guidance for which engineering plastics suits particular applications. One advanced resource to determine particular products for particular properties is provided by the Dotmar website. The more detail known on how and where the material will be used, the better chance users have of precisely matching the grade to the application.