About 100 years ago, the invention of plastic was considered to be a boon for human life. It was a decent substitute for glass, metal, rubber, ivory and shellac. Earlier, only commercial sectors, like manufacturing industries, used this plastic. But, as time passed on, it began to permeate practically all facets of our daily life. According to recent statistics, the world’s plastic manufacturing reached 367 million metric tonnes in the year 2020, which is indeed a huge number!
All this plastic revolves around us in one or the other form starting from the pen you write to the clothes you wear. Here, the most intriguing question arises once you are done with the plastic, where does it go? The answer is – it goes to the trash can. Imagine millions of tonnes of plastic getting transformed into the trash every year. Although plastic made life more convenient for humans, it hasn’t been very kind to the earth.
Among the huge heap of plastic rubbish, plastic bottles contribute a significant amount. You may locate plastic bottles anywhere around you, like packaged juices, soft drinks, and even medicinal syrups. This ubiquitous nature makes them the most preferred candidate for packaging purposes.
Since plastic bottles have become an indispensable part of our lives, we need to know where their journey starts and how it ends. With the help of this content, you will get to know how the manufacturing, distribution and disposition of plastic bottle occurs.
Content: Plastic Bottles
What are Plastic Bottles?
It refers to bottles constructed from high or low-density plastic material. We utilize them for various purposes, such as storing carbonated beverages, soft drinks, shampoo, medicines, oils, milk, ink etc. Nowadays, bottles made up of PET, i.e., polyethene terephthalate, are the most common.
Manufacturing Plastic Bottle
The life cycle of plastic bottles contains 5 processes:
- Raw material extraction
- Manufacturing
- Distribution
- Packaging & Transportation
- Usage
- End of the life cycle- Disposal
1. Raw Material Extraction
In order to create plastic for plastic bottles, the first step is the extraction of raw materials. This raw material includes crude oil and natural gas, which are refined to ethane and propane. Around 8 – 10 % of the total extracted crude oil is utilized in plastic making. Different components of crude oil are segregated, known as fractions. Each of the fractions is a distinct mixture of hydrocarbon chains and is separated as light, middle and heavyweight fractions.
Note: As per the estimations, plastic-making industries use about 12 million barrels of oil every year.
The ethane and propane undergo a heat treatment process known as cracking. This transforms them into ethylene and propylene. The monomers of these materials bond together to generate different polymers, such as PET which are used as raw materials for plastic bottle production. Here, the final raw material is tiny pellets of plastic.
2. Manufacturing of Plastic Bottles
The formed pellets are heated and melted together under a shearing action of a feed screw. The melted plastic is then poured into the moulds of small tube cavities to generate preforms. The preforms consist of neck and thread, which will form the future cap and bottle.
During the heating process, the preforms are loaded into the feeder and passed via unscrambler for feeding and orienting them into the blow moulding machine. Inside the machine, a thin steel rod, ‘mandrel’, slides inside the neck of the preform. The air is pumped through this pipe with high pressure, and the preform tube expands axially and radially, the same as that of a balloon. The mould is then quickly cooled to set the internal structure. Either the water stream or cooled air is used for this process.
3. Packaging and Transportation
After the manufacturing process completes in the bottling plant, the bottles are ready for transportation and filling the desired product. The freshly packed bottles are shipped to grocery stores and other marketplaces from where you buy them and take them to your home.
4. Distribution of Plastic Bottle
Freshly packed water bottles dispatch from bottling companies to the grocery store, vendors, and other places. These are stations or venues that sell the packed bottles to the consumer.
5. Usage of Plastic Bottle
Plastic bottles became producers’ and consumers’ first choice for packaging because of their lighter weight, comparatively low production cost, and easy transportation. However, the greatest advantage of plastic bottles is their higher resistance to breakage than glass. Plastic bottles are mainly used to package soft drinks, juices, water etc. As the consumers consume the internal product, they throw the plastic bottle in the trash can.
6. Disposal: End of Lifecycle
From the trash can, the plastic bottle can have three fates:
a. Disposal in Landfill
b. Recycle
c. Reuse
Disposal of Plastic Bottles
Unfortunately, a vast majority (73-90%) of plastic bottles end up straight in dumping yards or landfills. They stay there for hundreds and thousands of years before their decomposition process starts. This plastic debris continues to pollute the environment throughout time.
Recycling Plastic Bottles
Although making a plastic bottle requires a lot of material and hard work, it still ends up as garbage. Even though there are potent chances of their revival, people consider it as waste and rashly throw them away.
But even today, we cannot consider recycling plastic bottles as an ultimate solution because the frequency of recycling is very low.
Most people are not even aware of the fact that they can recycle bottles to make useful products again. For instance, plastic bottles can be transformed into polybags or even new bottles.
How to recycle plastic bottles?
- For recycling, the bottles are firstly segregated from the other waste and brought to the recycling plant. There they are sorted as per their colour.
- Further, they are shredded into flakes of plastic. These flakes are cleaned by continuous washing with water. This help in removing dirt, stuck glue, sand, paper etc.
- Later with the help of a floating sink or washing line method, the plastic flakes are cleaned with water and detergent. This removes labels, caps, germs etc., from the bottle surface.
- These plastic flakes are then subjected to high heat, i.e., (above 160° C) to melt them down. After melting is completed, they are transformed into resin pellets which are sort of plastic beads.
Note: At this stage, these beads are free to get converted into any desirable plastic product like polybags, chairs, tables etc. - The resins are again melted and poured into a mould of preforms to form new bottles. These preforms are easy to transport due to their smaller sizes.
- The preforms are soft enough to expand with hot and pressurized air. It expands the plastic towards the edges of the bottle mould, which gives it the proper shape of a plastic bottle.
- Quickly the blow mould is cooled to set the plastic, and a brand-new recycled bottle is ready for use.
Reusing Plastic Bottles
We can use plastic bottles for gardening or storage purposes, making decorative items like lamps, pen stands, ropes etc.
Plastic Bottles Pollution
The bottles made up of plastic bring convenience and instant refreshment. We often use, throw and forget about them. It is hard to believe that 1.3 billion bottles per day add to the already piling plastic waste.
These bottles make up a sizable portion of this massive mass of plastic waste that may stay around long after we die. This is because plastic waste requires around 450 years to start its decomposition process.
The production of plastic bottles requires a significant investment of resources, time and energy. However, their afterlife brings with it a whole new set of environmental issues. We dispose them off into garbage tins; they either end up in landfills or in the depths of oceans. Both circumstances stimulate the situation of a plastic crisis, or one must say a crisis due to plastic.
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