We come in contact with plastic products in our everyday activities. Interestingly, not all of these plastics are considered safe for use in health-conscious industries such as food, medicine, and beverages.
It’s no surprise that regulatory bodies such as the FDA have placed a ban on the use of harmful plastics in these industries. So, let’s take a look at the list of “safe” FDA approved plastic filaments to use for 3d printing.
PLA
PLA is one of the most common plastics used in 3d printing. Unlike other filaments, Polylactic acid (PLA) is produced from renewable sources such as starch.
Hence, it’s completely biodegradable, and can be used to produce from already existing plastic manufacturing equipment. Therefore, PLA is cost-effective in addition to its biodegradable nature.
It’s no surprise to see that this bioplastic is a used asset in health-conscious industries such as medicine, food, and beverages. For instance, PLA is utilized in producing biodegradable medical objects such as screws, plates, and rods. It’s also used in making plastic bottles, and food wraps, thanks to its ability to constrict under heat.
Besides, its application in these industries, PLA is majorly used in plastic injection molding, where it is printed in the shape of an interior cavity before being encased with other materials.
Mode of Production
Basically, this plastic filament is made through two processes – polymerization and condensation. The former also referred to as an open ring polymerization, utilizes metal catalysts in conjunction with lactides to create PLA filaments with higher molecular density.
The latter, although similar in process, differs in the temperate range used during production. More so, the products(condensate) are different.
Properties of PLA
Moving on to the characteristics of PLA, let’s examine some of its crucial properties as an FDA-approved plastic filament;
- A sharp contrast to petroleum-based plastic products, PLA is completely produced from the polymerization of starch from carbohydrate-rich sources.
- PLA is considered a carbon-neutral compound. Since it is produced from renewable and sustainable sources, and it’s zero impact on carbon emissions.
- As a thermoplastic, PLA plastic becomes liquid at a temperature above 150 degrees without a significant change in structure. Therefore, users can easily recycle this material, as opposed to thermoset plastics which can only be heated once.
- Mind you, PLA in the liquid or vapor form is considered toxic if inhaled or absorbed into the skin.
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TPU/TPE
Due to the incompatibility of rubber in 3D printers, flexible filaments with the same level of elasticity have been developed for use in these printers.
Flexible filaments such as Thermoplastic elastomers (TPE) and thermoplastic urethane (TPU), made from a cross-link of rubber with plastic, are now utilized in the production of materials such as car tires and rubber bands. More so, these filaments are utilized in sporting goods, footwear, and even medical devices
Due to its inert nature, regulatory bodies such as FDA, have approved the use of these filaments in health-conscious industries. Mind you, the use of TPE in food packaging and beverages is still being closely monitored, as it’s regarded as a Legally Food-Safe Material.
TPE and other types of flexible filaments boast of an impressive resistance to weathering and chemicals. No doubt, this property makes it an excellent food packaging material. In fact, a recent conference on TPE showed the use of this material as a safe alternative to PVC materials in food packaging, medicine, and sportswear.
Mode of Production
Thermoplastic elastomers and other types of flexible filaments undergo a process similar to the vulcanization process used in rubber production. Via polymerization technique which requires the copolymerization of two or more monomers, thermoplastic is able to exhibit more than one characteristic.
In this material, one monomer provides an amorphous or soft segment while the other provides the crystalline solid segment, which also acts as the thermal stable component. Unlike the reversible vulcanization process, flexible filaments transition from a liquid (melt) state to a solid flexible material that’s reversible.
Properties of Flexible Material
- Fungus resistance is a prized asset in the food packaging industry. Due to the clamp-down on the use of most preservatives, flexible filaments are the ideal candidate for sealing medical devices, food, and beverages from fungal attacks in the form of molds and decay.
- Flexible Filaments such as TPE and TPU, have an impressive UV resistance ratio, high heat resistance, and solvent resistance. Therefore, you can use these materials in handling food and other health-sensitive materials.
- Let’s not forget it’s high tensile strength, high versatility, and abrasion resistance in various applications.
Nylon
No doubt, this is one of the most popular and versatile filaments in 3D printing. No doubt, its versatility lies in its ability to mix with different additives to form a variety of materials with different structures.
Nylon materials, known for their tough and flexible nature, offer a high abrasive and impact resistance. Thanks to its diverse physical properties and price affordability, this material can easily replace and mimic the tensile strength of brass, steel, and even rubber at a lesser price.
Besides these properties, nylon materials such as the FDA-Approved Ertalon 6 PLA nylon, are chemical and corrosion-resistant. In addition to this, nylon resins are an important component of food packaging materials where an oxygen barrier is crucial for maintaining the freshness of food products.
Since nylons are high temperature-resistant, they are used for sausage sheaths and meat wrappings. With this material, you can easily machine it and fabricate it to precision via 3D printers and CNC machines. So, let’s take a look at how nylon filaments are produced.
Mode of Production
Polymerization reaction also comes into play in the production of this organic compound. Nylon is manufactured when the appropriate chemical building blocks (monomers) are combined through a rigorous condition to produce long-chain polymers via polymerization or condensation. Sometimes, nylon polymer chains can contain as many as 20,000 monomer units connected via an amide group.
For example, the monomers for the popular FDA-Approved nylon 6-6, are hexamethylene diamine and adipic acid. These monomers are specifically chosen for their high-chemical resistivity and heat resistance. What’s more? Water is released as a by-product and instantly removed since it hinders the continued formation of polymer chains.
Properties of Nylon
There’s a bid for more efficient machines without compromising on the strict hygiene standard prevalent in many industries. In fact, this has spurred the need for materials with both tribological and mechanical properties.
- Nylon-metal composite, for instance, is valued for its high tensile strength, durability, elasticity, and resistance to chemical attacks. This material is also drawn into filaments and utilized for the use of yarns, cordage, and fabric.
- In the fabric and textile industry, resilience and longevity are important in the manufacture of fabrics
- Nylon materials such as polyester are known for the ability to maintain their smooth appearance, and wrinkles are easily removed.
- In addition to this, nylon materials with open construction can help radiate heat from the wearer, while those with closed construction helps to trap-in heat.
- Let’s not omit the low absorbency rate of nylon materials in textiles, food packaging materials.
PETG
Here’s an extra-tough 3d filament that’s not only recyclable but it’s considered safe by the FDA. It has an extremely high tensile strength that’s ideal for creating sturdy prints.
More so, it’s considered a better alternative to PLA and ABS, due to a smoother finish and lower shrinkage during printing. As a variation of Polyethylene Terephthalate (PET), PETG has the ability to withstand moisture, act as thermal insulation material, hence, making it conducive for food packaging.
More so, the glycol addition to PET results in a plastic filament that’s more durable, less brittle, and stronger. In fact, PETG’s inability to become brittle when overheated makes it an excellent material for medical devices.
Mode of Production
As mentioned earlier, this composite plastic filament is a variation of PETG. Thanks to the addition of glycol in the manufacturing process, this material has a lot of advantages over its predecessor, PET.
As an oil-based polymer, this material constitutes 3 main components – terephthalic acid, glycol, and cyclohexane dimethanol. No doubt, this is considered a relatively simple process that involves the combination of two or more monomers in varying concentrations.
Properties of PETG (T-glass)
Properties such as high thermal conductivity, chemical resistance, and moisture resistance, are important criteria for selecting materials in health-sensitive institutions and industries.
PETG meets these criteria, and it’s no surprise to see industries such as Food and beverage packaging industries utilizing this material.
In addition to this, some Red Cross Chapters also utilizing this material for their Vial of Life Program; a container where you can store your medical history in the case of an emergency. As a thermoplastic, it’s recyclable without any form of degradation in structure or properties.
PCL
The PCL or Polycaprolactone, is a popular flexible plastic filament utilized in the production of Thermoplastics such as TPU, and other types of plastics like Polyvinyl chloride (PVC). This polymer helps to improve the end-use properties and processing characteristics of most thermoplastics.
Polycaprolactone’s popularity, no doubt, stems from its biodegradable nature which is considered a positive property in the approval of materials for everyday use. Unlike other types of biodegradable plastic, this material is also bio-absorbable, i.e; the body can easily degrade this material without incurring any harm or hindrance to normal bodily functions.
These characteristics make it an indispensable asset in controlled drug release mechanisms and medical implants. Sadly, this filament is not an ideal candidate for tissue engineering due tt its low mechanical strength and cell adhesion.
Mode of Production
This filament is produced via a ring-opening polymerization reaction. Through the help of a set of catalysts, the ring-opening polymerization reaction yields a semi-crystalline, water-resistant polymer with a low melting point of 63 degrees. Furthermore, PCL has a -60 degrees glass transitional phase.
Properties of PCL
PCL is a homopolymer that has infiltrated into the field of medical implant and drug release mechanisms.
For instance, it is used as a component of dental splints and can also act as a root canal filler in lieu of the gutta-percha, a less effective alternative.
With respect to its biodegrade and bio-absorbable nature, the FDA recently approved the use of this filament as a suture under the brand name; Maxon. More so, researchers recently discovered the collagen-mimicking effect of PCL in removing wrinkles and other signs of aging in seniors.
PEEK
Obtained through step-growth polymerization, PEEK is a semi-crystalline thermoplastic known for its high heat and chemical resistance.
It’s no surprise that this is regarded as the highest performing thermoplastic, and it is commonly used in demanding applications such as oil, automobile, aerospace, and most importantly, medicine.
From piston parts to high-performance chromatography columns to electrical cable insulation to bearings, PEEK materials are specifically built to withstand and bear demanding applications.
Also, PEEK or Polyether ether Ketone is considered as an advanced biomedical material. Its application in this field extends beyond its use as a partial replacement skull in different neuro-related applications. Interestingly, this material is also utilized in spinal fusion devices in the treatment of spine-related injuries.
Mode of Production
These polymers are obtained via a step-growth polymerization by the dialkylation of bisphenolate salts. Another way to achieve a similar result is a reaction between disodium salt of hydroquinone and 4,4′-difluorobenzophenone at a high temperature of 300 degrees in diphenyl sulphone.
Properties of PEEK
As a semi-crystalline thermoplastic, PEEK boasts excellent chemical and mechanical properties that are even retained at high temperatures.
Conclusion
There’s a need for an increased awareness of the use of harmful plastics in our everyday activities. More so, the presence of carcinogens in plastics such as Poly Vinyl Chloride (PVC), has driven manufacturers to search for safe plastics.
By utilizing these FDA-approved plastics for your 3D printing, you will be able to avoid health hazards.
