Thermoplastic Resins

The Building Blocks of Plastics

Most synthetic polymers and biopolymers converted into thermoplastic resins for injection molding (also extrusion, compression, rotational, and blow molding) are hygroscopic, meaning they will tend to absorb moisture from the air. Exposure to the naturally-occurring water vapor in air will cause these polymers to undergo a chemical reaction called hydrolysis, which breaks the polymer chain's covalent bonds. This process reduces the polymer's molecular weight and can significantly reduce its mechanical properties.

Excessive moisture in a hygroscopic polymer can disrupt the molding process through hydrolysis and result in visual defects like splay, poor surface finish, bubbles, or delamination. Hydrolysis can also significantly alter the physical properties of the polymer, leading to reduced strength, increased brittleness, dimensional instability, poor heat resistance, and a tendency to warp. Typically, hygroscopic polymers require proper material drying, with moisture removed through dehumidifying processes such as desiccant or vacuum dryers.

Preventing Hydrolysis

Clearly, it is important for compounders to keep thermoplastic resin materials free of moisture to avoid hydrolytic degradation. IMPAK is uniquely situated to offer our 30 years of experience and a line of tested and trusted materials to create sorbent systems that will keep hygroscopic polymers safe from moisture. While we do produce high moisture barrier bags and high performance desiccants in volumes sufficient to have inventory on hand for immediate fulfillment, we also regularly create custom packaging, including custom laminate films, to meet the unique demands of a variety of industries.

Products to Protect Plastic Resins

MylarFoil Box Liners / Gaylord Liners

IMPAK produces a variety of large-format pouches that are made from high barrier MylarFoil materials such as our PAKVF4C. When sealed properly with quality equipment, these pouches are guaranteed to protect contents from moisture and other contaminants.

MylarFoil Drum Liners

If you are transporting nurdles in 55 gallon drums, or drums of any size, IMPAK has a variety of options available. Our drum liners, or round bottom bags, are also suitable for packaging and shipment of fluid products such as liquid resins, and high heat tolerance materials are available.

Large Clay Desicant Bags

For maintaining a low RH in large-scale environments, 5 lb bags of Montmorillonite Clay desiccant are frequently the first choice. These bags are commonly used to keep shipping containers free from "cargo sweat" and are relied upon to keep vehicles and large products moisture-free.

Molecular Sieve Desiccants

For industrial-grade applications in which maintaining a moisture-free environment is crucial, we recommend highly effective molecular sieve desiccants. Read more about what makes molecular sieve the best desiccant.