How to maximize post-consumer recycling in plastic production


injection molding How to maximize post-consumer recycling in plastic production

Source: press release

Sustainability is not only driven by government regulations, but consumer demand and environmental awareness around the world are driving more and more companies towards sustainable applications. Mold-Masters offers injection molding solutions for both bioresins and PCR.


Mold Masters’ solution enables injection of high PCR content as a core layer of up to 50 percent of the total part weight without compromising part quality or cycle time.

(Source: Mold Masters)

Utilizing their co-injection multi-layer technology, Mold-Masters is able to combine two separate resins into a single 3-layer melt flow. This allows the company to inject high PCR content as a core layer up to 50 percent of the total part weight without compromising part quality or cycle time. In their recent production application, Mold-Masters implemented a 2-cavity co-injection system to produce 5 gallons. (20L) bucket. Each of these 700g pails contained 50 percent PCR as the core layer. According to the company, this solution has the potential to generate significant savings for the caster (based on current prices) by reducing the use of virgin material and TiO2 (compared to traditional single-layer buckets). Those savings and favorable ROI mean that sustainability initiatives can also make financial sense, Mold-Masters argues.

The company first introduced this feature in 2015 as part of its advanced co-injection technology. Mold-Masters claims to have tip control that allows them to precisely control core layer distribution and thickness. This allows the company to inject a higher percentage of PCR content than competing systems. Many competing systems would be limited to incorporation of up to 35 percent, which could limit sustainability goals and significantly impact the ROI of implementation, the hot runner and injection molding solution maker continues, adding that having unified control allows them to achieve more consistent and achieve more complete core fill that their patented “fold-over” capabilities would provide a technical advantage that allows them to achieve the highest core percentage. This, in turn, allowed them to ensure even distribution and full coverage of the PCR resins (prevents contact of the PCR with the product).

Another key difference pointed out by the manufacturer is the ability to randomly position the core. For example, in packaging applications, customers may prefer to keep any auto-generated PCR core away from the injection point to avoid built-in stresses that can lead to brittleness and unsuccessful drop tests.

The co-injection technology does not sacrifice cycle time and existing tools can be reused. A variety of materials can be combined, although those with similar melting temperatures are ideal for compatibility. Many applications use the same material (e.g. 50% virgin HDPE, 50% PCR-HDPE). Mold-Masters thermally isolated manifolds allow two thermally dissimilar resins to be combined.



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