What Is PETG?
Polyethylene terephthalate glycol, commonly known as PETG or PET-G, is a thermoplastic polyester that provides significant chemical resistance, durability, and excellent formability for manufacturing.
PETG can be easily vacuumed and pressure-formed as well as heat-bent thanks to its low forming temperatures.
This makes it exceptionally popular for consumer and commercial applications that involve 3D printing, or other heat-forming manufacturing techniques. Additionally, PETG is well-suited for fabrication techniques like die cutting, routing, and bending.
How is PETG Made?
PETG is produced using a two-step, melt-phase polycondensation process. This relatively simple process joins two different monomers together, accompanied with the release of a small molecule such as water.
PETG can be injection moulded, sheet extruded or extruded as a filament for 3D printing. This clear, amorphous thermoplastic can also be coloured during processing.
In order to understand how polyethylene terephthalate glycol is made, it is important to first understand how PET was discovered and created.
Advances in polymer chemistry in the mid-20th Century saw scientists discover new materials that could be used instead of traditional organic products.
Phthalic acid polymers were in use in paints and varnishes, while glycol-based synthetic fibres were being used in textiles. However, the phthalic acid products were too soft to be used as fibres and the glycol-based materials had melting points too low to allow for their use in textiles.
British scientists, John Whinfield and James Dickson combined these substances in 1941 to create polyethylene terephthalate (PET).
Using the process of esterification to heat glycols with terephthalic acid, they created long-chain molecules of PET that could be turned into fibres with high melting points low dissolvability.
PET became widely used in textiles by 1946 and by 1952 PET was being used as film for food packaging. In 1976, PET was used for the manufacture of rigid bottles that could manage carbonated soft drinks, beer and mineral waters.
Despite being one of the most widely used plastics today, PET does have some disadvantages, including being susceptible to crystallisation at high temperatures. This turns the PET opaque and weakens its structure.
The creation of polyethylene terephthalate glycol-modified, or PETG, replaced the ethylene glycol in the molecular chain with a larger monomer, cyclohexane dimethanol, which stopped the crystallisation associated with PET.
With improved heat resistance, PETG molecules do not collect together as easily as with PET, which lowers the melting point and inhibits crystallisation.
This means that polyethylene terephthalate glycol can be used for thermoforming, 3D printing and other higher temperature applications without losing its properties.
What are Properties of PETG
Easily formed, die-cut and punched, PETG is a solid choice for applications in which complex shapes, details, deep draws and compound curves are featured. This thermoplastic material polyethylene terephthalate glycol can also be painted, silk screened or hot-stamped.
Exceptionally durable, PETG offers engineers great design freedom and is suitable for many applications. With better impact strength than acrylic and lower cost than polycarbonate, PETG is the superior choice for many complex fabrications. Characteristics include:
- Durable and tough
- Good chemical resistancehere to help 200
- High impact strength
- Good clarity
- Easily formed, die-cut and punched
What Are the Benefits of PETG Plastic?
PETG is strong and cost-effective when compared to either acrylic or polycarbonate. Its unique characteristics make it preferable for impact-resistant glazing and high strength display units. Suitable for digital printing, PETG lends itself to product materials, displays, and signage.
In general, PETG is a food-safe plastic that’s commonly used for food containers and bottles for liquid beverages. Like acrylic and many other thermoplastics, PETG is fully recyclable.
PETG is both thermoformable and vacuum-formable, and can tolerate a tremendous amount of pressure without cracking. Although PETG is naturally clear, it takes color easily during processing. It can be injection molded into a variety of shapes, or extruded into sheets.
PETG’s damage resistance is far higher than that of acrylic, to the point that it rivals the impact resistance of polycarbonate. However, PETG fabricates easily, making it an easy material for both practitioners and professional fabricators.
Applications of PETG
Thanks to its easy thermoforming and chemical resistance, PETG has many uses. It is commonly used in single use and reusable drinking bottles, cooking oil containers, and FDA-compliant food storage containers.
However, PETG is also found across the medical field; its rigid structure allows it to survive harsh sterilization processes, making it a perfect material to be used in medical implants, as well as pharmaceutical and medical device packaging.
PETG is an excellent material to use in modern 3D printers, and is quickly becoming a favorite among the community as it becomes more accessible. With the correct print settings, PETG filament prints easily, has excellent layer adhesion, and is odorless while it prints.
It also has very low shrinkage properties, which enables larger prints than materials like PLA or ABS. At the same time, it’s extremely strong and has great chemical resistance. This allows it to print objects that can sustain high temperature, food-safe applications, and exceptional impact.
Diving deeper, PETG plastic is often the material of choice for point-of-sale stands and other retail displays. Since it’s easy to manufacture in a wide range of shapes and colors, businesses often turn to PETG material for eye-catching signage that attracts customers.
Plus, the added benefit of easy printing helps make customized, intricate imagery an affordable option.
The properties of polyethylene terephthalate glycol make it suitable for a wide range of different applications, including:
#1. Food and Drink Containers
Because it has good chemical resistance and is easy to thermoform, PETG is widely used for items such as cooking oil containers, drinking bottles and FDA-compliant food storage containers.
It is also used for cosmetics packaging and the light weight and high strength delivers advantages for distribution costs and effectiveness.
#2. Medical and Pharmaceutical Applications
The rigid structure of PETG means that it can survive harsh sterilisation processes, which makes it an ideal substance for medical implants as well as packaging for pharmaceutical and medical devices.
#3. Retail Stands and Displays
polyethylene terephthalate glycol is widely used for point-of-sale retail stands and displays. Since it can be coloured, it is also ideal for signage.
#4. Machine Guards
PETG is also used to manufacture machine guards. The clear plastic is easy to form while also offering protection for users. PETG guards are often used in food processing as they are easier to form than polycarbonate and more durable than acrylic.
#5. 3D Printing
As mentioned above, PETG has gained popularity for use in modern 3D printers. A polyethylene terephthalate glycol filament prints easily and provides excellent layer adhesion.
Low shrinkage rates allow for larger prints than with PLA or ABS, while PETG is also strong, chemical resistant and odourless while printing.
It is advised that a cooling fan is used while printing with PETG, while problems with printing bed adhesion can be overcome by putting down a layer on the build plate.