Plastic isn’t perfect; all plastic types come with their natural limitations, and finding the right material that accounts for user considerations is an important step in product development.
However, plastic has also evolved significantly since its early test tube days. Originally fabricated from just a few natural materials, today it is created from a combination of various materials, both raw and synthetic. With this evolution also came the emergence of transformative polymer additives and modifiers, which have continuously changed the face of plastic production.
Additives and modifiers are a substances which are mixed in with plastic materials to create a complex formula. The plastic pellets are melted down before they’re combined with special, altering substances, in a process called compounding. Together, they create a complex ‘polymer formula’. Then, they are turned back into pellet size, before being grinded down into the powdered plastics we use here in our factory. This process changes properties, characteristics and behaviours of plastic materials.
As once said by Jimmy Dean, you can’t change the direction of the wind, but you can adjust your sails to always reach your destination. In plastic manufacturing, we do this with additives and modifiers. Plastic may not be perfect, but when we chase perfection, we can reach excellence. From glasses and helmets to beauty packaging and pharmaceutical goods, each product has a purpose, and additives exist to help a product achieve that purpose. Some of these additives are simply reinforcements, such as increased strength or longer lifespan. Others are essential to ensure usability and safety.
At Rotadyne, our plastics are regularly tested to determine its performance and effectiveness, and we can attribute its success to the influence of additives. Areas of targeted improvement include strength, durability, aesthetic and branding, functionality and production and processing, all which ultimately impact the quality and capabilities of the final product.
PRODUCTION AND PROCESSING
At times, it is during production stages that plastic parts face their greatest threat. Ensuring that the material is properly treated and processed is essential in securing good results, and much effort is placed in maintaining the plastics strength, resistance, aesthetic and functionality. Some additives used for this include flow enhancers, plasticisers, heat stabilisers, anti-static agents and lubricants.
Before the plastic is ever placed into the mould, the casting is covered with an even layer of lubrication which assures the plastic will not adhere to the mould itself and can be easily removed once cooled without damage. Flow enhancers are also commonly added to help improve the flow between individual plastic particles as they melt and combine. They facilitate the creation of more intricate moulding projects as the plastic is able to enter narrow cavities.
Antioxidants prevent the part from oxidizing inside the mould, and protect the material from thermal degradation. Plasticisers also help with the materials mouldability, making it softer and more flexible. In general, plasticisers are also technically the oldest type of additive; water is considered a plasticiser in pottery, where it helps the clay become a pliable, workable material.
Heat stabilisers make sure the plastic is able to melt without decomposing.
When work is tough, we gotta be tougher! Or at least our plastic does. These popular additives work to increase the overall strength of your product. Specifically, they work to target properties such as impact strength, brittleness and bearing strength. These additives include toughening agents, cross-linking agents and impact modifiers.
Toughening agents are elastomeric materials, assisting by distributing applied stress evenly and broadly across the plastic, rather than it being concentrated in one location. This prevents damage from rapidly applied weight and increases its overall strength.
Cross-linking agents, however, are the powerhouse of the strengthening additives category. They work at a molecular level of the part itself, fusing the material into solidified part. This increases the products resistance to warpage and provides it with excellent stress crack resistance.
We see these additives applied in products such as vehicle parts, agricultural and military equipment, and even luggage! The holiday might not last long, but you can ensure your suitcase does!
Meanwhile, some additives are unique from the strength enhancers as they relate less to weight stressors, and instead address environmental factors. Woody Hayes once said we should aim to “paralyse resistance with persistence”. With plastic, however, we’d rather see it persist to resist. These additives also include chemical resistants, which ensure protection from corrosive substances so that your plastic is prepared for contact with toxic chemicals. With UV stabilizers, antimicrobials, and bio stabilisers, your part is perfectly designed for durability.
UV stabilisers are used largely in outdoor applications, as they help to protect the material from the damaging effect of sunlight, especially in harsh Australian climates.
Antimicrobials and bio stabilisers, meanwhile, reinforce protection against discolouration, odours, bacteria, and cross contaminations. They also sustain the materials electrical insulation and aesthetics for an extended product life cycle.
These additives are especially useful for products such as wires, cables, electrical appliances, medical applications and other outdoor equipment. It’s also featured in spandex; they really allow us to stretch our imagination and uncover the possibilities!
AESTHETICS AND BRANDING
They say beauty is on the inside; with plastics, that may literally be the case. Branding is also an often overlooked component of product development and launch, at times the look of your product making the difference between creating something that simply works, and something that’s on our wish list. The addition of certain additives such as pigments and dyes, fragrances, antioxidants, anti counterfeiting, and antifogs address your products beauty needs at a molecular level, so your design can be art.
Perhaps the most common additives are pigments and dyes, which serve to permanently infuse colour into the material. Newer and increasingly popular additives are fragrances, which provide plastics with a lasting pleasant scent, particularly helpful for products which are susceptible to being contaminated with foul smelling odours during or after their use. Both these additives are essential to branding; colour and scent are known as the most powerful associative triggers with the ability to define user experience.
As aforementioned, plastic is not typically the biggest fan of the sun, and can be quickly eroded by its harsh rays, especially in the extreme climates experienced here in Australia. However it can effect more than impact strength; UV stabilizers are commonly used to assist in protecting the material’s aesthetic qualities from thermal degradation, which can cause elongation, surface cracks and discolouration.
Most products can benefit from additives which increase strength, durability, or even to make the final part easy on the eyes with a pop of colour. However, lesser used additives often more prove to be the determining factor to the core function of the product. These additives are not the most popular, however when they are required, they can be incredibly critical for user safety.
Antifog additives are an example of this. As the name suggests, these help to eliminate fogging effects to maintain the materials transparency. When combined with the virgin plastic, this additive reduces surface tension between the humidity’s liquids and the solid plastic, which allows water droplets to be uniformly layered and therefore effectively “defogs” the plastic. For products such as helmets or glasses, this is an understandably essential feature.
In rotational moulding, anti-static agents improve surface conductivity, reducing the likelihood of ‘sparks’ which can cause a variety of issues. Ranging from attracting dust, to causing explosions and damaging electronics, anti-static agents are great for household and furniture industries. Meanwhile, fire retardants are useful for creating fire resistant plastic products which don’t combust when heated up, and helps it to exhibit good burning behaviour by not releasing deadly amounts of toxic smoke and fumes.
Less common are anti-counterfeiting additives; these are an optical brighter which absorb and then reflect UV light with a blue hue. These are useful as they allow manufacturers and brand owners to combat counterfeiting. In certain industries, such as pharmaceuticals or electronics, these also serve as a protective preventative measure when dealing with products which are potentially dangerously when imitated. Finally, they can also contribute to brand security, and helps customers verify that your product is the real deal.
Ultimately, without additives, plastic just wouldn’t work out. Importantly, this process demonstrates how your products design doesn’t end with surface-level features, but instead runs deeper to its molecular design. Essentially, additives allow manufacturers to edit the material to perform better in production, and most importantly make it compatible with the user’s experience, both in commodity and specialty applications. Additives give plastics purpose.
Whatever the practical need of the product, Rotadyne will do our best to accommodate for it. In the words of Helmut Schmidt, the biggest room in the world is the room for improvement. Plastic is used across a wide range of key industries, from automotive to aeronautics, from healthcare to smart devices. When working with an array of unique products we find that perfection becomes a moving target, but one which we can effectively strive for; with just a bit of help from compounded chemicals.