With superior foamability and homogenous cell structure, polypropylene (PP) foam is an ideal choice for applications across packaging, sport, transport, and construction.
As a leader in the polyolefin industry, we are committed to designing advanced foam solutions, which enable circularity and reuse.
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A: It depends on the type of foam you want to produce. Hydrocarbons like iso- or n-butane are typically used to produce very low density foams, whereas inert gases like supercritical CO₂ or N2 are commonly used to produce higher density foams (over 200 kg/m3).
A: Yes, Daploy™ HMS PP can be used with chemical foaming agents, which are often supplied as masterbatches. These are most commonly used to produce high and medium density foams.
A: The most commonly used foaming technology is extrusion foaming. However, Daploy HMS PP is very versatile and can also be used to produce expanded PP beads, for foam blow molding, and occasionally for foam injection molding.
A: Yes, you’ll need to add a foaming agent—either physical or chemical—and a nucleating agent to control the cell structure. You can also include other polymeric and non-polymeric components depending on the required properties of the foam application.
A: You can produce foams as thin as 700-800 µm. At the other end of the scale, thicknesses of up to 10 mm or slightly more are possible, depending on the foam density and the cooling capacity of the line. The main challenge when producing thicker foams is cooling the core quickly enough to prevent the structure from collapsing.
A: Often yes, although minor hardware modifications might be needed. However, if the foaming line wasn’t designed for PP, you may see lower output or reduced foam quality. Because heating and cooling performance can affect foam stability, we recommend testing these systems on your line before running PP foaming trials.
A: Flat dies can be used to produce extruded foams with densities of 200 kg/m3 or more. For lower densities, we recommend annular dies.
A: In many cases, yes. If your line doesn’t have a gas injection unit for physical foaming, you can use chemical foaming agents instead. However, using this method, the reduction in material density is usually limited to about 30%.
A: During production, foam cells tend to align more in either the machine or transverse direction, which affects the mechanical properties. You can improve the balance by adjusting the nucleating agents and production conditions.
A: Yes, simulation software can be used to estimate basic foam properties, which will significantly shorten development cycle times. However, results should be treated as indicative—final performance should always be confirmed in real production trials.
A: At Borealis, we define it as:
A: Daploy HMS PP offers higher melt strength than standard polypropylene, which improves processability, foamability and helps maintain homogeneous foam structure—while retaining the temperature resistance typical of PP. In addition, it supports material efficiency and helps reduce production waste, making it well suited for circular applications.
A: Yes. Daploy HMS PP supports the production of lightweight, monomaterial foam solutions that are fully recyclable and durable enough for reuse. By enhancing material efficiency and significantly reducing production waste, it helps to minimize resource consumption and lower CO₂ emissions. These sustainable properties are instrumental in supporting compliance with the upcoming requirements of the PPWR.
A: Yes. Foamed PP made with Daploy HMS PP can be used on its own or combined with non-foamed PP layers to create 100% PP monomaterial packaging. This supports easier recycling today and helps meet the future design-for-recycling (DfR) criteria under the EU’s PPWR.
It also supports compliance with the End-of-Life Vehicles (ELVs) Directive by enabling recyclable monomaterial solutions that contribute to reuse, recycling, and recovery targets, and by helping to reduce the use of heavier materials in new vehicles.
A: Physical foaming: In physical foaming, gas is injected into the polymer melt to create a foam structure. This method allows for precise control over foam density and cell structure, making it ideal for achieving lower foam densities with superior insulation properties—supporting energy savings in various applications. It also offers sustainability benefits, as it typically uses gases like CO₂ or N2, which have a lower environmental impact than chemical foaming agents. Additionally, physical foaming can reduce material use and production waste, lowering costs.
Chemical foaming: In contrast, chemical foaming uses additives—chemical foaming agents—that release gas during processing. This eliminates the need for a gas injection unit, simplifying equipment requirements. However, it typically limits the achievable density reduction. Chemical foaming is therefore best suited for applications where only moderate density reduction is needed or when retrofitting existing lines. While easier to implement, it may involve the use of chemical agents with a higher environmental impact than the gases used in physical foaming.
In summary, physical foaming offers greater control and more sustainability benefits, while chemical foaming provides simplicity and flexibility—especially when using retrofitted existing equipment.
A: Yes. Expanded polypropylene (EPP) offers recyclability in the existing recycling system and supports compliance with future sustainability regulations such as the EU’s PPWR. These advantages make EPP a great choice for modern packaging needs.
A. Yes. Daploy HMS PP is available based on renewable feedstock or chemically recycled (PCR) using the mass balance approach certified according to ISCC Plus. These materials offer the same performance and regulatory compliance as virgin grades, including food contact approvals, making it easier to meet your sustainability targets.
Our Bornewables™ portfolio offers premium polyolefins made from renewable feedstocks derived entirely from waste and residue streams. One of the key benefits is reduction of the carbon footprint. According to a Life Cycle Assessment (LCA) performed in 2021* to assess the potential environmental impacts of polyolefins made from renewable feedstocks, the partial carbon footprint of PP could be reduced by ca. 2 kg CO2e/kg PP when produced using renewable feedstock compared to its equivalent fossil-based PP.
Borcycle™ C is our portfolio of virgin-equivalent polyolefins created from post-consumer waste using advanced chemical recycling technology. These materials are ideal for high-performance and contact-sensitive applications.
*Critically reviewed LCA performed following the ISO14040/44 standards, using the Ecoinvent 3.6 database