For most customers. they regard PET is as the same as PETG. But as a PET and PETG manufacturer and supplier, we know well their different details. Here we will table their differences. To let you know what is PET vs PETG?
1. Different definitions
PETG is a transparent, non-crystalline copolyester. The commonly used comonomer of PETG is 1,4-cyclohexanedimethanol (CHDM, Cylclohexylenedimethylene).
PET plastic is the abbreviation of English Polyethylene terephthalate, referred to as PET or PETP.
Compared with PET, the biggest feature of PETG is that PETG complies with the concept of environmental protection and food FDA certification. PETG is currently receiving more and more attention from related products.
2. Different uses
PET is mainly used for the packaging of various beverage containers, such as pure water bottles and cola-like beverage bottles.PETG is used in all kinds of long-lasting daily necessities. Such as cosmetic bottles, perfume bottles, pharmaceutical packaging containers, and so on.
3. Chemistry and performance
PET for beverage bottles is produced from terephthalic acid (TPA) obtained from the oxidation of p-xylene. Terephthalic acid is purified or reacted with methanol to produce dimethyl terephthalate (DMT), or further oxidized to produce pure terephthalic acid (PTA). Another basic raw material of PET is ethane, which is converted into ethylene glycol (EG) by the reaction.
PET is a polycondensate formed by the polymerization reaction of DMT (or PTA) and EG in the continuous molten state. Then in the solid-state polymerization process, large crystal grains, final molecular weight and inherent viscosity are obtained. This solid-state process also keeps the ethanol content of the polymer sufficiently low.
The general commercial PET resin melts at about 480F. However, the melting point of highly crystalline PET is about 520F.
4. Different Features
PETG sheets are easy to produce products with complex shapes and large stretch ratios. Moreover, unlike PC board and impact-modified acrylic. This board does not need to be pre-dried before thermoforming. Compared with PC board or acrylic, its molding cycle is short, the temperature is low, and the yield is higher.
The molecular structure of PET plastic is highly symmetrical and has a certain crystal orientation ability. So it has high film-forming properties and properties.
PET plastic has good optical properties and weather resistance. And amorphous PET plastic has good optical transparency.
5. Identification method
5.1 PET plastic
5.1.1 Smell the taste first. The taste of PET is different from ordinary plastics. Use a lighter to burn it, and then you will smell a very aromatic and comfortable taste (fire a bottle to smell it). If the PET contains other ingredients, the taste will be very pungent. nose. Some kinds of bottles containing SEBS ingredients cannot be used.
5.1.2 Look at the burned part, if the black is distributed or the oil drops. Most of the melting points are abnormal, which is often found in PET film.
5.1.3 Wire drawing. Wire the lighter while it is burning. See if the silk is long or not, and then pull the silk to break. Look at the breakpoint in the middle. Is the silk rolled into a small circle? The more volume, the higher the melting point.
5.2 PETG plastic
PETG plastic is transparent plastic and an amorphous copolyester. The commonly used comonomer of PETG is 1,4-cyclohexane dimethanol (CHDM), which is called polyethylene terephthalate. Alcohol ester-1,4-cyclohexanedimethanol ester.
5.2.1First of all, it is a kind of transparent material, so transparent materials will be chosen for comparison many times below.
PETG/PCTG is first of all a highly transparent plastic. It has excellent optical properties, a high gloss surface, and low turbidity. Its light transmittance is close to 90%. It is very close to acrylic (pmma) and better than polycarbonate (PC).
5.2.2 PETG/PCTG has a wider range of chemical resistance (such as coffee, chocolate, oil, acid, etc.).
It has excellent chemical resistance to the following chemicals. Automotive oils, soap liquids, detergents, detergents, carpet cleaners, toothpaste and peppermint oil, perfumes, cooking oils, 2-propanol, hydrocarbon solvents, etc. ,
5.2.3 It is one of the few environmentally friendly plastic materials so far. The reason why it is said to be an environmentally friendly material. Because it only leaves CO2 and water after being burned, which can protect nature well.
Since 2006, many developed countries such as Europe, America and Japan are vigorously advocating the use of environmentally friendly materials similar to PETG (PETG has SGS, FDA, MSDN certification).
PETG has become one of the preferred alternatives to non-environmentally friendly transparent materials. Such as PVC. Need environmentally-friendly plastics, PETG should be the first choice.
5.2.4 PETG/PCTG is particularly suitable for forming thick transparent products.
PETG products with thick walls can maintain the same excellent light transmittance. PETG/PCTG products have a transparent ice blue background color that caters to the world trend. Their surface is extremely delicate and has a super visual effect.
In addition, their thick walls Or inside the solid product, it is not easy to produce bubbles during processing. (We have a lot of transparent samples for guests to watch, and these samples belong to major brands).
5.2.5 PETG/PCTG has extremely high toughness, excellent tensile properties and good impact resistance.
Among transparent plastics, PC has the best toughness and impact resistance. But its stretchability is not good.
Acrylic has poor tensile properties, toughness and impact resistance.
PETG has extremely high toughness and excellent stretch resistance. Performance, its maximum stretching ratio can reach more than 180%. Its impact strength is several times that of acrylic, but slightly worse than PC.
At the same time PCTG is a wide range of transparent plastics, which is close to the impact strength of PC. One, PCTG has the reputation of being “not bad”, which is derived from its super toughness.
The super toughness greatly reduces the fracture of the finished product during the secondary processing, transportation, installation and use, and greatly reduces the overall cost of the finished product. Another outstanding advantage of PETG/PCTG is: Its physical and mechanical properties hardly change at low temperatures.
5.2.6 They have fun secondary processing performance. Excellent ductility makes a variety of secondary processing methods of PETG/PCTG possible.
You can perform laser cutting, milling, die cutting, drilling, welding, punching, hot bending, cold bending (less than 2.5 mm), screw/rivet/bolt connection or fixing on their products. And the second processing performance of PC is poor. Because PC is more prone to stress concentration during molding.
Once one of the above secondary processing methods is performed, it will break the stress balance of PC products or cause product cracking.
5.2.7 They have excellent printing Performance and coating performance.
That is to say, the surface of PETG/PCTG plastic products can be printed. Such as spraying, silkscreen, pad printing, hot embossing. Even spraying without any special corona treatment. The bonding performance with the surface coating well
Although PETG/PCTG has a wide range of chemical resistance, it cannot be guaranteed to be able to withstand all solvents in the sprayed material. Customers are requested to customize the sprayed material suitable for PETG in advance.