hemp filler polypropylene

Tips and Tricks To Compounding Hemp Filler with Polypropylene

The challenges associated with compounding hemp filler into polypropylene

Hemp fiber is an incredible crop with a long history of performing in rigorous environments. Plastic compounding is one of those environments in that hemp fillers have an opportunity to thrive. In order to successfully use hemp fillers it is important to be able to overcome the challenges involved with distributing and compounding natural products.

Bonding and Performance

Hemp is one of the strongest natural fibers, but to unlock the performance benefits you need to properly bond the fiber to your polypropylene. The chemistry of hemp filler and polypropylene are different and need to be bonded together at a molecular level.

Handling of Hemp Powder

Hemp filler in a powdered format, which is commonly found on the market, is hard to handle and dangerous. Hemp filler has a low bulk density, which makes it extremely hard to feed into the compounding process. In addition to difficulty compounding, powder introduces a wide range of dust, moisture, and flammability problems that are associated with natural fibers. These need to be accounted for with your supplier of hemp fillers.

Degradation of the Fibers

Hemp is a natural product, which means it will degrade at lower temperatures than other synthetic or mined materials. It is important to make sure that during the compounding process, you do not degrade the fillers by exerting too much heat or pressure.

Palmer Holland Hemp

Tips and Tricks to see success compounding hemp filler with polypropylene on your first try.

Watch Your Temperature During Compounding

The strength of hemp fibers is a crucial performance factor. One of the biggest factors that damage the strength of the hemp filler is too much temperature. For polypropylene, we would recommend using a masterbatch version of hemp filler that is engineered to withstand the temperature of compounding and molding.

The Format of Hemp Filler Is Important For Handling

When looking to source hemp filler, it is important to know the preferred characteristics for your production process. Hemp filler can be delivered in two formats, a powder (standard on the market) and a masterbatch. Powdered materials require on-site drying, and specialized handling equipment to prevent fires and OSHA dust violations. Using a masterbatch solves all the handling problems associated with natural fibers, including flammability, dust, moisture uptake, and bonding.

The logistics costs associated with shipping powder vs masterbatch can determine the viability of hemp fillers in your use case. If the producer is far away from your manufacturing site or requires multiple distribution sites, it is expected to see a major cost increase. Masterbatch will weigh out in a truck and allow you to reduce the cost of your logistics.

Simple Additives Improving Bonding and Performance

Hemp fiber bonds with hemp fiber really well. When you look to bond hemp fiber with polypropylene, they have a much harder time staying together. To functionalize hemp filler, you can utilize the same ingredients that you currently use to improve bonding for talc, calcium carbonate, or glass fiber.

This is important because you will see a significant increase in the performance of the composite by improved bonding with polypropylene.

Palmer Holland Hemp

Determining The Best Hemp Filler For You.

Functionalized For Your Process

Developing a hemp fiber that is easy to handle and process, has been treated to prevent flammability and dust concerns, and will bond with your product is a challenge. Heartland’s imperium masterbatch product is designed to solve all of the standard challenges associated with hemp fiber from distributors or the spot market.

Distance To Your Facility

It is important to understand your hemp fiber producers’ long-term vision for farming, processing, and distributing their hemp. The Heartland team is focused on a local farming empowering local manufacturing model, which intends to place production within 150 miles of our customer’s facilities. This will reduce costs and provide a sustainable supply of materials.

Supplier With Scale

Farming is a fractured business. It is important to be working with a producer that intends to match your global scale, providing you with materials in any region of the world as you grow your business.

Palmer Holland Hemp

Heartland’s Approach to the Industrial Hemp Supply Chain

Heartland’s hemp-based materials can make hundreds of different types of manufactured products stronger, lighter, cheaper, and more sustainable. Even though we have many R&D projects rolling in various industries, the perfect prototype project was plastics, and we’re gaining serious ground.

Highest Performance

Imperium fillers consistently outperform competitive hemp fiber in a 1:1 study. Heartland has a simple approach to processing that improves tensile strength and impact, while other materials can only accommodate one of these metrics. The imperium product line has been functionalized to bond with a wide range of mineral and synthetic product lines.

Lowest Cost

Cost reduction can be done by optimizing a few key aspects: direct access to the producers, improved processing of fibers, and proximity to the farm. All of these factors add pennies to the cost and can determine the viability of hemp fiber.

Heartland has developed unique farming models that reduce production costs by upwards of 50% for hemp fiber. This model enables a robust farming infrastructure that will support our customers in North America, Europe, and Asia between now and 2025.

Our model has been developed to have our facilities within 150 miles of our customer’s manufacturing, eliminating costly logistics that are associated with natural fibers.


Supporting global manufacturing requires a local supply of hemp fiber. It is important for our growth model that we can produce hemp fiber within 150 miles of our customers, reducing logistics and product costs while improving sustainability.

Palmer Holland Hemp

A More Focused Approach to Farming Imperium Filler

By focusing on understanding our customers better, we will build a more reliable industrial hemp supply chain that focuses on solving problems for those businesses who are actively looking for alternatives – and that number increases daily!

A properly executed industrial hemp processing facility requires Big-Ag infrastructure. This includes:

  • Large farming partnerships (10,000+ acres).
  • Large processing capacities (10,000,000+ pounds of hemp per month).
  • A customer base that has demand for hundreds of millions of pounds.

This is the only way to create a stable supply chain that farmers, investors, and manufacturers can trust. At the end of the day, the only way that hemp is valuable to a manufacturer is if it can be applied in mass manufacturing with a reliable, efficient, and consistent product. Our Imperium products hit those targets.

Just a few years ago, most farmers who had committed to industrial hemp were growing small batches (dozens or hundreds of acres tops). The lack of supply did not allow companies to use hemp-based materials regularly. Today, Heartland is leading the charge with thousands of acres (in Michigan alone) and we will represent a full 15% of industrial hemp in the United States!

Join us in creating a carbon negative future!

Heartland Team

Palmer Holland Hemp