Foam Biobased open-cell
Foam Biobased open-cell PU foam Achieving sustainability in product design can be challenging when not all biobased materials and sustainable plastic product development processes are created equal. Manufacturers should not have to sacrifice the quality of their products to create more sustainable offerings. When designing components with porous polymers, manufacturers can achieve high-quality material solutions using biobased, recycled, or biodegradable plastics, replacing porous components made from single-use plastics. However, it’s critical to understand the various technical considerations for porous polymers based on technology and functionality in order to explain how best to design with sustainability in mind. Creating a durable, more sustainable product with biobased polyurethanes One of the main technology platforms used to manufacture porous polymers is a two-step open-cell foam manufacturing process. Open-cell foam technology is developed using proprietary or customized blends of raw materials through a clean polyurethane foaming process without the use of catalysts. Different formulations offer wide-ranging densities, porosities, and levels of softness to meet specific customer requirements. This unique technology is made using a highly specialized manufacturing process and can be found in many applications. These porous materials are then assembled into the end product – such as a cosmetic product, a medical-grade foam for wound dressing for burns (see picture), or a patient positioning device used in hospitals. While biobased polyurethane might not be more recyclable than traditional polyurethane, it can be used in open-cell foam to lessen the final product’s dependence on fossil fuels and replace some of the ingredients in the pre-polymer with biobased urethanes to create a largely bioplastic-based solution. Unlike conventional polyurethane foam, open-cell polyurethane foam is hydrophilic and can absorb (e.g.) water up to 15 to 20 times its weight. Open-cell foam is also a hypoallergenic material that is non-crumbling, latex-free, and customizable in color. Additive ingredients can be included to help create product differentiation. In biomedical applications, open-cell foam can be used as an antimicrobial medical foam that better absorbs fluids during use, allowing the wound dressing to last longer and be fully used before disposal. Because of its flexible porous structure, open-cell foam can be used for cosmetics to make applicators more durable and effective to minimize waste in the overall product lifespan. That said, in order to ensure that the open-cell foam component will perform as desired with a product, it must be custom-engineered and manufactured to the right specifications. Not the typical manufacturing process Polyurethane foam can be manufactured in two different ways. The more traditional manufacturing process consists of one step and is used for large-scale manufacturing of foam used in items like seat cushions, bedding, or other similar goods. The one-shot process creates a large bun of foam by simultaneously mixing all ingredients at one time. The one-shot terminology comes from the process of all ingredients being combined into a conveyor or a mold, where the chemicals are simultaneously reacting with each other and immediately creating the foam expansion. This often By: Avi Robbins, Vice President Global Product Development and R&D Porex Fairburn, USA includes the addition of harsh chemicals or catalysts to create the foaming reaction. However, when looking at smaller-scale applications that require more control over pore size, pore structure, and overall foam characteristics, a more unique two-step process is needed. Instead of using chemical agents to create the reaction and catalysts, this process uses a large amount of water to react with the pre-polymer formulation. By taking the proper ratio of pre-polymer and pairing it with a water-based solution, a chemical reaction can begin that creates carbon dioxide gas. The presence of this gas, in turn, spurs foaming action and creates the pore structure of the foam. This process provides the ability to control the chemical reaction and the ingredients to manipulate pore size, pore structure and, finally, the properties of the foam. Ultimately, this control allows resulting open-cell foam structure to better support the end product’s functional specifications. Partnering with an innovative supplier Open-cell foam is custom engineered to the end product’s requirements. For example, a wound dressing manufacturer can specify and develop a foam with pore structure built for high absorption capacity, helping to withdraw the exudate from the wound and provide a more sanitary, comfortable, and effective treatment. In a cosmetics application, manufacturers can take the same approach of tailoring foam pore structure to optimize flowthrough for viscous cosmetics formulations, enabling uniform coverage and consistent product performance. Understanding the nuances between these types of product segments and the pore structures their material components require is critical for achieving a successful product design. When working toward a more sustainable product and involving a supplier to provide biobased polyurethane, it is key that the partner holds material expertise to help guide the manufacturing process and ensure design optimization. Porex, a global leader in porous polymer solutions, can recommend different materials to achieve the ideal open-cell foam component. This collaborative effort enables Porex to pinpoint the proper chemical formulation and manufacturing process to yield a foam equipped with the right properties for the end-product. When consumers invest in a more sustainable product, they expect the same quality as the alternative, traditional product. As more manufacturers venture out to create these eco-friendly goods with biobased polyurethane, seeking the ideal expert partner is essential. By taking a strategic, tested approach to material design and production, manufacturers can enhance their own sustainability credentials while upholding existing performance standards – building customer loyalty and market differentiation. www.porex.com 34 bioplastics MAGAZINE [01/21] Vol. 16
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