The OptiMISER System
Plastic Blend Formulating & Optimizing
Plastic Blending Basics
The plastic blending process allows you to combine properties of multiple components and generate blends for optimized performance. Blending offers the opportunity to utilize lower cost resins while maintaining or improving product performance. Blending can lower costs, improve throughput and tailor material specifications to your products. Blending can also produce a unique set of properties that are not available in a single resin.
Same performance at lower cost
The key to routine output of high-quality products starts with a clear understanding of the product requirements and the material performance properties for each resin. When properly formulated, blends can perform with the same characteristics and reliability as virgin materials, but at lower cost.
How resins behave
In general, all resins are composed of a distribution of polymer chains with a different number of repeat strands or units. Because of this distribution of chain lengths, and thus molecular weights, describing the resin using just MI and density is inadequate for many applications.
But molecular weight and its distribution are critical considerations. Here’s why:
- In the melted state (called “extrudate”), molecular structure determines the processing characteristics
- In the solid state, molecular structure determines the all-important performance properties of the final product
- A wide distribution of molecular weights (a wide range of variations in chain lengths) makes extrudate easier to process
- A narrow distribution of molecular weights (less variation in chain length, more typical with virgin resins) makes extrudate more difficult to process
Polyethylene grades and properties
Polyethylene is available in a wide range of grades. The OptiMISER System works with all grades of polyethylene.
- Wide-specification PE
- Regrinds (post-industrial and post-consumer)
- Reprocessed (post-industrial and post-consumer)
In the 50+ years since plastics became viable materials for many products, experts have determined that there many material properties that affect resin behavior in very important ways. A few of the frequently used properties are below:
- Environmental stress crack resistance (ESCR)
- Flexural modulus of elasticity
- Flexural strength
- Impact strength (determined via the Izod impact test or the Dart impact test)
- Melt index (MI)
- Modulus of elasticity
- Molecular weight
- Molecular weight distribution
- Rheological properties
- Sag resistance
- Slow crack growth
- Tensile modulus of elasticity
- Tensile strength
Plastics behavior is determined by a wider range of specifications than simply melt index and density. Blending for MI and density alone does not ensure good processability or product performance. This is one reason why two different lots of the same polymer may have the same melt index and density but exhibit different behavior during processing.
The need for pre-blend testing
The growing availability and lower cost of recycled polyethylene resins makes them very attractive alternatives to virgin material.
To develop a successful formulation, you must know the key properties of each of the materials for the applications you’re working with. Not only does The OptiMISER System use material characterization, it offers you low-cost, rapid material characterization techniques. Once the materials are tested, the data is used in The OptiMISER System’s advanced formulization software.
Formulating a successful blend with The OptiMISER System
The technology starts with accurate material characterization. With this information, two or more components are brought together in an ideal combination to reshape and optimize key properties.
With The OptiMISER System, all the complex blend calculations are managed by the software, keeping the manufacturing process simple.
The enhanced resin combinations generate substantial material cost savings.