Reclaim is the hot new thing. There’s reclaimed barn wood, reclaimed pallets, reclaimed barrels and the list goes on and on. Reclaiming might be the newest “in” thing in the decorating world, but not so much in the rubber industry. There’s more than a subtle difference between reprocessed and reclaim rubber, and the difference could affect your product greatly. So, what are reclaim and reprocessed rubbers, and what’s the big dif?
Reclaiming has been going on since the beginning of the rubber industry. There were several companies that existed solely to produce reclaim and, until the late 20th century, it was common for U.S. rubber companies to have a reclaim facility on site. Reclaiming was especially important to the U.S. during the Second World War when rubber was scarce and critically needed to support the war effort.
Reclaim is derived from rubber products that undergo a composition change when they’re initially formed. These products are collected after they’ve been discarded, then broken down chemically, added to, and reformed into new products. Sounds simple enough, right? Let’s take a closer look at what’s going on under the surface.
When vulcanized rubber products are created, they undergo a crosslinking process that occurs when chemicals such as sulfur, accelerators, filler, process aids and carbon black are mixed with the rubber polymer to create a compound. The compound is then ready to be heated and molded into a thermoset part.
The Reclaim Process
The material for reclaim comes from vulcanized molded rubber products: tire treads, inner tubes, natural rubber gloves, etc. Vulcanization is what gives rubber its toughness and resiliency and why, unlike plastics, rubber parts cannot simply be reground and recycled. When reclaim rubbers are created, the crosslinked carbon chains in the rubber are broken down via de-vulcanization. The process of de-vulcanization starts with grinding the parts. Through heat, pressure, and the introduction of certain chemicals, the crosslinking of the carbon double bonds is reversed. The de-vulcanized rubber is then milled into thin sheets and finished into slabs.
All of the present-day traditional reclaim processing plants in the U.S. have shut down due to the detrimental environmental impact of the chemicals used in the de-vulcanization process, as well as the high cost of reclaiming itself. Reclaim is still readily available but produced in India, Asia and Southeast Asia and exported to the U.S.
Where Reprocessing Comes In
Reprocessing is what Goldsmith & Eggleton does in Wadsworth, Ohio, and it’s entirely different from reclaiming. The rubber used is not cured, post-consumer scrap or de-vulcanized because it isn’t necessary since it has never been crosslinked. Material for this process comes from manufacturers of synthetic rubber and is considered industrial or post-industrial. The polymer may be wet, have variable viscosity, off weight or misshaped packages and so forth. The important thing to understand is that the feedstocks are 100% pure synthetic rubber.
Reprocessing is entirely mechanical in nature, using large internal mixers, pelletizing extruders, mills and balers. The chemical composition of the material is never altered. Instead, it’s cleaned, homogenized and tamed down the variability that is inherent with feeds. The reprocessed product is similar to and compatible with the prime rubber it replaces in the rubber compound formula in chemical composition, physical properties and appearance. Reprocessed products are less expensive than prime products, so they can be used as a viable cost reduction option for purchasers.
So Why Choose Reprocessed Rubber Over Reclaim?
Both reclaim and reprocessed products can be used in a rubber compound formula as a cost reducer, though the approaches to creating them are entirely different.
- Reprocessed products are more environmentally friendly than reclaim.
- Reclaim is much more expensive than reprocessed material.
- Cured parts (like what’s used in reclaim) are typically less than 50% raw rubber—the other 50% is cure chemicals, process oil, carbon black, fillers and process aids. Reprocessed rubber is 100% rubber.
- Since there’s no limit to where reclaim comes from, there’s no control over what’s actually going into reclaim rubber. Inputs are closely controlled and only acquired from known producers when making reprocessed rubber, and it’s unchanged when it goes through reprocessing.
- Reprocessed rubber has essentially the same chemistry and very similar physical and performance properties as prime polymer in a rubber compound.
- The highest concentration of cost in a rubber compound is the rubber itself. Reprocessed rubber that is typically used in conjunction with prime product makes up 20% loading or replacement level. The result is a more cost-effective end product with little to no effect on performance. You get more for your money in a formula with reprocessed rubber than reclaimed rubber.
While both products are routinely used in various industries today, there are clear differences between the reclaim and reprocessed products. The superior attributes of reprocessed rubber, including consistency, technical specifications, repeatable product characteristics, reliability of supply, and ease of use as an effective cost down option make it an easy win over impure and hazardous reclaim.