Plastic is a very versatile material. By slightly modifying its chemical composition, its properties can be changed significantly. And we see the example first hand in the different plastic products that we use on a daily basis.
Consider the plastic bag. They are available in different specifications and sizes. However, the classification can be divided into two – Consumer packaging and Industrial packaging.
Industrial plastic bags are much different than what we get from the grocery store. The plastic bags that we use to carry stuff from stores to our homes are lightweight and thin products that can carry a certain amount of load. However, they are not suitable for carrying heavy loads.
Industrial packaging plastic bags can carry significantly higher load than ordinary plastic bags. But this is just one use case. The types of plastic bags used in industry changes based on the requirements.
Strength – Load Carrying capacity
This is where the density of the plastic comes into effect. High-Density Polyethylene or HDPE is the strongest among plastic bags due to its high density. high-density plastics can hold heavy loads but can tear from sharp objects.
Linear Low-density plastic or LLDPE is very flexible thanks to the molecules being places apart and can withstand tearing or puncturing to a large degree. This makes them the prime choice for carrying sharp objects. They are not as strong as HDPE.
LDPE or Low-Density Polyethylene is the least dense of all plastic. It is not used to carry heavy loads and is not as flexible as LLDPE.
So when strength is the only concern, the choice is high-density plastics. HDPE or High-Density Polyethylene is a high-density plastic that can carry a load much more effectively the LDPE or Low-Density Polythene.
Due to the high density of HDPE (0.93 to 0.97 g/cm³), it is more rigid when compared with low-density plastics. HDPE is used in industries like food, beverage, pharmaceuticals, and consumer goods.
Chemical resistance of plastic bags is critical in industries where load that they are carrying is chemically corrosive. Plastic is generally chemically resistant. However, as the reactivity of the chemical increases, it can damage even plastics.
Hence, HDPE is still the most favored choice for packaging chemically corrosive substances. Industries use HDPE packaging more often than the alternatives.
LPDE plastic bags can get damaged when they are in direct contact with powerful corrosives. However, they are still useful against low to mildly corrosive chemicals, making them suitable for ordinary use.
FDA or Food Drug Administration is the Federal Agency of the US that regulates rules and regulations pertaining to consumables. Since plastic bags are one among the most common type of food and drug packaging material, the FDA has clear guidelines on what to use and what not to use.
Food items in the US can only be packed with FDA approved plastics. Using any other form of plastic is illegal and may lead to adverse events like food poising, consequently a criminal case. Let us review some of the FDA approved plastics that are available for packaging.
HDPE High-Density Polyethylene
Like we discussed before, HDPE or High-Density Polyethylene is one among the prime choices for packaging food because of its chemical stability. The plastic does not absorb much moisture nor does the plastic mix with the food.
It is safe and has excellent heat resistant qualities.
LDPE or Low-Density Polyethylene
LDPE is also approved by the FDA as plastic granted that It is not made from 100% PCR LDPE resin. Food grade LDPE plastic bags are used to pack food or for transportation purposes. It is the more popular option thanks to the low cost of manufacture.
Polypropylene is a very lightweight plastic thanks to its very low density, hence they are ideal for packaging. The inert characteristics of the polypropylene bags have gained them FDA approval to be used for packaging food and drugs.
Clarity or Transparency
You might have noticed that some plastic bags are very transparent, while some are opaque or translucent. Even though dyes can be added to give the plastic color or visual enhancements, the clarity of the plastic mainly depends on its density.
HDPE: High-Density Polyethylene have the polymers closely packed together, this makes the bag opaque. HDPE garbage bags are a prime example where they are either in black or blue showing no signs of transparency.
LDPE: Due to the low density of this plastic, the bags made out of them are either transparent or has mild cloudiness to them. They are often dyed to get a tint. In essence, LDPE has the highest clarity or transparency among packaging plastics.
MDPE: Medium Density Polyethylene bags stay between HDPE and LDPE when it comes to density. And you can see that its properties are a mix of the two extremes. Clarity of MDPE can be defined as partially cloudy or translucent.
Another important difference between plastic bags for general use and industrial use is the gauge size. Basically, gauge size is the thickness of the plastic bag. The higher the thickness, the stronger it becomes.
The plastic bags used for general use and industrial use are different because their requirements are different. Plastic bags in industrial packaging are made to withstand harsher use cases when compared with normal consumer-grade plastic.
And knowing the difference between the two helps you to make the right purchase decision for your packaging needs. Need more helping on choosing the right packaging? Contact BorderPak and have all your packaging questions answered today.