Making an Impact; Sustainable Materials Available at Montrose Molders

By Brendan Wilson

Plastics waste represents one of the greatest environmental issues we face today. At Montrose, we believe that a transition to recycled and bio-based plastics is the first step towards mitigating the effects of this ever-growing challenge. For this reason, we are positioning ourselves as an organization that can both source sustainable materials reliably and process them into parts expertly.

Once difficult to source and of variable quality, the availability and consistency of sustainable plastics has greatly improved in recent years due to increasing demand on the regulatory and corporate levels.

Sustainable plastics materials can be broken down into five main categories:

· Post Industrial Resin (PIR)

· Post Consumer Resin (PCR)

· Biodegradable and Compostable

· Bio-Reinforced and Bio-Filled

· Ocean-bound

In this blog, we’ll discuss each of these categories and the positives and negatives that you should consider before designing one of these materials into your next project.

Post Industrial Resin (PIR)

When industrial plastic parts reach the end of their lifecycles, they are brought to a facility where they are cleaned, grounded, and repalletized for reuse. PIR feedstocks are also derived from the waste generated during the manufacture of industrial goods. This type of recycled plastic represents the most widely available and most economical option of all the sustainable materials that will be discussed in this blog.

Point of Purchase (POP) display produced using HIPS recycled PIR

Historically, PIR was available only in black, but more options for clear and natural materials are hitting the market as more producers are cleaning and sorting waste materials more efficiently prior to reprocessing.

Clear samples produced in recycled GPS PIR

Below is a list of PIR materials available at Montrose:

Material	Colors Available
ABS	White and Black
HIPS	White and Black
GPS	Clear and Black
CoPP	White, Grey, and Black
HDPE	Grey and Black

Below are the pros and cons of using PIR in your next project:

Pros	Cons
Makes use of landfill-bound plastic	Color can be inconsistent from lot to lot
Easy to source large values with minimal forecasting	Natural and clear colors still difficult to find
Relatively low cost	Occasionally difficult to process due to contaminants.
Wide variety of colors available

Post Consumer Resin (PCR)

Like PIR, PCR is produced from discarded plastic parts. Unlike PIR, however, the source is the plastic you bring to the bottom of your driveway on recycling day. Old water bottles, peanut butter jars, and milk jugs are conveyed to a recycling plant, sorted, cleaned, ground, and repalletized for reuse. Because most of this plastic once held perishable food, the cleaning process can be more arduous, rendering contamination more likely.

Below is a list of PCR materials available at Montrose:

Material	Colors Available
R.PET	Clear
HoPP	Clear

Below are the pros and cons of using PCR in your next project:

Pros	Cons
Makes use of land-fill bound plastic	Contamination is common, though cleaning processes are improving
Promotes sustainability and proper recycling practices	Number of sources still limited, but are growing
	More expensive than PIR due to resource-intensive sorting and cleaning process

Biodegradable and Compostable

Commonly labeled “Bioplastics,” these materials are not traditional hydrocarbon derivatives, but rather produced from renewable sources such as sugar or corn. They represent the most significant innovation in the fight against plastics waste because they break down in the environment under certain conditions.

Below are the main types:

• PHA (Polyhydroxyalkanoates) - produced from renewable resources such as sugars and oils. PHA is marine-biodegradable, meaning that the bacteria in the ocean will break it down over time.

• PLA (Polylactic Acid) - produced from renewable resources such as corn starch, cassava roots, or sugarcane. PLA is compostable, but not marine-biodegradable.

• PolyEarthylene – Plant based bio-resin that mimics olefins like PE and PP

While this category is very exciting and holds much future potential, for now, these materials are very difficult to process efficiently and incredibly energy intensive to produce, leading many to question their carbon footprint. Additionally, bioplastics cannot be introduced to conventional recycling streams because their composition differs from traditional plastics.

Hook produced in green Polyearthylene

Below is a list of biodegradable and compostable resins available at Montrose:

Material	Colors Available
PHA	Natural (various colors)
PLA	Natural (various colors)
PolyEarthylene	Natural (various colors)

Below are the pros and cons of using these materials in your next project:

Pros	Cons
Mostly biodegradable	Difficult to process
Not conventional hydrocarbon based thermoplastic	Mechanically weak
Great sustainability impact	Not recyclable

Bio-Reinforced and Bio-Filled

Bio-reinforced and bio-filled materials add natural filler to traditional thermoplastics like PP, PE, HIPS, and ABS. The most common fillers are spent hemp discarded by the CBD industry and wood pulp, or cellulose, generated from lumber production.

Filler in percentages from 10-30% can be added to reach the desired plastic properties required for specific jobs. For example, fillers can add strength to plastics with weaker mechanical properties like PP or PE. Additionally, because these fillers are lighter and carry less heat than plastic, they tend to reduce part cost through reduced density and faster cycle times. For this reason, cellulose filled PP is becoming popular in the design of automotive components.

Tray sample produced in 30% cellulose filled PP

Bear in mind that filled plastics typically have a distinct texture and surface appearance. Another challenge is that not all colors are achievable when a filler is added.

Below is a list of bio-filled materials available at Montrose:

Materials	Colors Available
CoPP - Cellulose filled	Natural (various colors)
CoPP Glass Filled - Cellulose filled	Natural (various colors)
CoPP - Hemp filled	Earth tones
HDPE - Hemp filled	Earth tones
ABS - Hemp filled	Earth tones
HIPS - Hemp filled	Earth tones

Below are the pros and cons of using these materials in your next project:

Pros	Cons
Reduced hydrocarbon content	Filler is visible on part surface
Improved performance (improved mechanical properties from fillers)	Not recyclable through conventional waste streams
Reduced Cost (less weight, faster cycle times)	Limited colors in hemp material

Ocean-bound Plastics

Ocean-bound plastics tackles the twin issues of cleaning up existing waste and reducing future waste. These materials are reprocessed from plastics that have already, or could potentially, reach waterways such as rivers, streams, lakes, and oceans. These plastics are collected, sorted, cleaned, ground, and repalletized.

These materials have been available for years, but until recently were prohibitively expensive. Significant financial backing has led to the scale necessary to increase availability and reduce pricing.

Below is a list of ocean-bound plastic materials available at Montrose:

Materials	Colors Available
HDPE	Natural (various colors)
HoPP	Natural (various colors)

Below are the pros and cons of using these materials in your next project:

Pros	Cons
Great, marketabel story	Limited Supply, but growing
Mechanical properties and processability of conventional recycled plastics like PIR and PCR
Lower Cost

Sustainable materials offer myriad benefits, ranging from reduced environmental impact and improved marketability to, in some cases, reduced costs.

We’re confident that Montrose is the best suited manufacturer to deliver these benefits to you and your company. Please reach out to us today to speak with a technical sales representative about which one of the options is the best solution to making your project a sustainable one.