When the PVC industry began to move away from lead-based stabilizers, industry experts knew it would be a challenge to find alternatives to the highly effective (but not environmentally friendly) lead salts and soaps. Although it took a lot of work to create effective alternative stabilizer formulations, lead-based stabilisers have successfully been converted to calcium and zinc-based stabilizers across the globe.
Today, the pressure is on to reduce costs. This often happens by lowering the addition rate of stabilizer one-pack in PVC formulations or by using lower-cost raw materials, which tend to be less effective and thus provide lower performance. In turn, lower-performing stabilizers narrow the processing window, making it more difficult for a PVC processor to minimize scrap production while increasing output of quality products.
Here are some tips for choosing a calcium-zinc stabilizer for PVC:
Stabilizers with consistent properties provide a wider processing window and greater cost-efficiency for manufacturers of PVC products.
Choosing a supplier with expertise in creating calcium-zinc formulations that provide comparable heat stability, lubricating properties, and durability as lead-based stabilizers is essential. When looking for a stabilizer supplier, the following factors should be considered:
A supply partner with robust research and development capabilities. Besides needing a stabilizer customized to your product and process, you should partner with a supplier who remains at the forefront of technology and will be able to evolve successfully when faced with market or regulatory changes.
A supply partner who can provide a consistent product. Batch-to-batch variation can be affected by raw material selection, dosing accuracy, contamination, and mixing efficiency. Be sure to choose a supply partner who has invested in systems that eliminate cross-contamination and increase dosing accuracy to ensure even distribution of highly complex recipes.
A supply partner with stringent control over process variables. The way in which the stabiliser one-pack is produced will have an impact on the batch-to-batch consistency of the one-pack. Stringent control over process variables is key to minimizing variability, but the foundation of this control is high quality in the design of the one-pack manufacturing facility. Eliminating the potential for cross-contamination, such as from additives that are not part of a given formula, is particularly important, because these unintended additions disrupt the accuracy of the intended blend, create variation, and can have negative interactions with the intended additives.
A supply partner who can help optimize dosage levels. An optimal dosage level can provide highly consistent products that meet strict quality standards and is key to high productivity rates.
Finally, it's important to consider total costs, not just the cost of the stabilizer.
A processor doesn’t want to pay for more stabilizer than necessary. But choosing an inconsistent stabilizer can end up being more costly because the processing window can narrow resulting in out-of-spec product and increased scrap.
The processing window of the PVC -- the range of variables such as melt temperature, melt pressure, dimensional stability, output rate and physical properties -- determines the output of a quality product. When a higher level of stabilization is used (typically achieved via a higher addition rate OR by using a more effective and often higher-cost raw material), the processing window is wider and can accommodate more variation. In this wide processing window, the natural variation in stabilizer one pack remains within the processing window, and as a result, “in spec” product is made.
Working with a supply-partner who has invested in R&D resources and equipment, and who takes the time to understand your process and output targets is invaluable when determining the total cost to your business of the chosen stabilizer.
About Orbia Polymer Solutions (Alphagary)
Orbia’s Polymer Solutions business Alphagary is a global leader in the design and manufacture of specialty polymer compounds and additives for polyvinyl chloride formulations including stabilizers, plasticizers and colorants. Compounds are generated from a variety of polymers including polyvinyl chloride (PVC), polyolefin (PO), thermoplastic polyurethane (TPU) and thermoplastic elastomer (TPE). With over 60 years of experience, Orbia Alphagary has earned its reputation for providing innovative, functional, durable solutions to a broad marketplace. Orbia Alphagary is committed to offering sustainable products formulated with bio-based and recycled content and actively participates in initiatives that promote a circular economy. Its compounds are trusted for a wide range of applications from data communications and power cables to various building and industrial products, automotive interior parts, a wide variety of consumer goods including food-contact applications and healthcare products. Orbia Alphagary offers standard and custom formulations to meet market-specific requirements and end users’ needs and is committed to health and safety best practices by maintaining ISO 9001, ISO 14001 and OHS ISO 45001 certifications. Orbia Alphagary has 1,000 employees across nine facilities across the U.S., UK, Mexico, Colombia and India, serving 80 countries through a global sales and distribution network.