Plastic Types 1 to 7: A Packaging Buyer's Guide to Resin Codes

Turn over a plastic bottle, tub or tray and you will often find a small triangle with a number inside. Most people read it as "recyclable". It does not mean that. It only tells you which plastic the item is made of.

There are seven codes. 1 is PET, 2 is HDPE, 3 is PVC, 4 is LDPE, 5 is PP, 6 is PS and 7 is everything else. In India, the Bureau of Indian Standards lists the same seven codes in IS 14534, its guideline for recycling plastics.

We have been making plastic packaging at JPPL since 1997, so these materials are our daily work. Below is the reference I wish every buyer had: where each plastic turns up in packaging, how to recognise it when there is no code, and what really happens to it after use.

The seven codes at a glance

Why should a packaging buyer care about the number?

Three reasons, and none of them is a chemistry lesson.

1. It decides whether your packaging gets recycled. A clean PET bottle or HDPE can has a buyer in every Indian town. A thermocol block or a mixed laminate usually does not.
2. It decides what the pack can survive. PP takes heat far better than PET. PS is brittle and cracks under a sharp knock. LDPE stretches where PET would split.
3. It shapes your compliance work. Under India's Extended Producer Responsibility (EPR) rules for plastic packaging, brand owners report by category, not by code. Category I is rigid packaging. Category II is flexible packaging, including single-layer and multilayer plastic. Category III is multilayer packaging with at least one non-plastic layer, and Category IV is compostable plastic. Knowing the resin helps you place each pack in the right category.

Code 1: PET (polyethylene terephthalate)

PET is the clear, stiff plastic of water bottles, soft drink bottles, edible oil bottles, clear jars and many thermoformed food trays. It is also used as a thin film in laminates.

How to recognise it: it is glass-clear and rigid, and it crackles when squeezed. It sinks in water. A PET bottle usually has a tiny raised dot at the centre of its base, where the plastic was injected. An HDPE bottle has a thin seam line across the base instead. When you fold PET sharply, the fold turns white.

What happens after use: PET bottles are the most collected plastic in India. Ragpickers and kabadiwalas pick them out first. Much of it becomes polyester fibre for clothing, carpets and fillings.

Code 2: HDPE (high-density polyethylene)

HDPE makes detergent and shampoo bottles, jerry cans, crates, bottle caps, some tarpaulins and the thin, crinkly carry bags that rustle loudly.

How to recognise it: it feels slightly waxy, it is usually opaque or milky, and it floats. HDPE film makes a dry rustling sound, quite unlike the quiet softness of LDPE.

What happens after use: rigid HDPE is valuable to recyclers and comes back as pipes, crates and new bottles for non-food use.

Code 3: PVC (polyvinyl chloride)

PVC turns up in blister packs, some clear clamshells, shrink sleeves on bottles, some cling films and in PVC tapes, including electrical insulation tape. We sell PVC tapes because certain jobs, like insulation and colour coding of cables, need that flexibility.

How to recognise it: it sinks in water. Rigid PVC is stiff. Soft PVC feels rubbery and stretches back.

What happens after use: very little PVC packaging is recycled. We see this clearly in the trade. Worse, a small amount of PVC mixed into a load of PET spoils the recycled PET. My view is simple. If another plastic or paper can do the job, do not use PVC in packaging.

Never burn PVC to test it.

It releases hydrochloric acid fumes.

Code 4: LDPE and LLDPE (low-density polyethylene)

This is the plastic I know best, because most of our film work is in this family. LDPE and its stronger cousin LLDPE make courier bags, stretch film, shrink film, carton liners, plastic bubble wrap, air cushion film and milk pouches.

How to recognise it: it is soft, it stretches a long way before it tears, and it floats. Pull a strip of a courier bag and it thins out like chewing gum before it breaks.

What happens after use: clean, unprinted LDPE film is easy to recycle and has buyers, especially stretch film from warehouses. Dirty, wet or heavily printed film is a different story. Most of it never gets collected. We, as film makers, have to accept our share of that problem.

On PackSmith, our courier bags and our LDPE film rolls are from this family, and we make liners from it too.

Code 5: PP (polypropylene)

PP is everywhere in packaging. The film in BOPP tape is polypropylene, stretched in two directions to make it strong and clear. PP also makes microwave-safe food tubs, bottle caps, woven sacks for cement, grain and sugar, and non-woven shopping bags.

How to recognise it: it floats, like PE, but it is stiffer. A PP tub lid bends again and again without cracking, which is why tiffin lids and flip-top caps use it. BOPP film feels crisp and glossy and is hard to tear until you nick the edge, and after that it splits easily.

What happens after use: rigid PP such as tubs and crates is collected. Printed and laminated PP film usually is not.

We make tape from it, so I will say it plainly. Tape on a carton is a small contaminant in paper recycling, which is one reason we also sell kraft paper tape.

Our brown and transparent packing tapes are BOPP film with an adhesive coat.

Code 6: PS (polystyrene)

PS comes in two forms. Solid PS makes disposable cups, yoghurt cups and the brittle clear boxes used for sweets and hardware. Expanded PS is thermocol, the white beaded blocks that protect televisions and appliances.

How to recognise it: solid PS is brittle and snaps with a sharp edge and a cracking sound. Thermocol crumbles into small white beads.

What happens after use: thermocol is mostly air, so it is bulky to collect and hardly worth a collector's time. Very little gets recycled. For protective packaging, paper does this job well now. Honeycomb paper and kraft paper bubble wrap replace thermocol corners and fillers in many ecommerce boxes.

Code 7: Other

Code 7 is the drawer where everything else goes. It includes polycarbonate (reusable water jars, some lenses), ABS (electronics housings, luggage), nylon, PLA and other bioplastics, and many multilayer pouches made of more than one plastic, like chips packets and shampoo sachets.

How to recognise it: there is no single test.

I would treat any unmarked pouch as code 7 until proven otherwise. If a pouch is shiny on the inside, it likely has a metal layer.

What happens after use: this is the hardest group to recycle, because the layers cannot be separated easily. PLA and other compostable plastics need industrial composting conditions to break down as promised, and most Indian towns do not have such a facility yet.

How can you identify a plastic without a code?

Four simple checks separate the main families. Use all four together.

1. The water test. Drop a small piece into a bucket of water with a drop of dish soap, so it does not ride on the surface. PE and PP float. PET, PVC and solid PS sink.
2. The stretch test. LDPE stretches a long way. HDPE stretches a little and turns white. PET and PS hardly stretch at all.
3. The bend test. PP bends without breaking. PS snaps. PET turns white at the fold.
4. The sound test. HDPE film rustles, BOPP crackles, LDPE is nearly silent.

One limit, and I want to be clear about it. These checks tell you the family, not the grade. They cannot tell virgin from recycled material, or food grade from industrial grade. For that you need the supplier's test certificate, so ask for it on every food-contact order.

And never use a flame test outside a lab. Several of these plastics give off harmful fumes when burnt.

Which plastic should you choose for your packaging?

My own rules, after many years of making and selling it:

1. Keep one plastic per pack where possible. A PE courier bag with a PE liner stays a single material. A pack of three different plastics glued together will not be recycled.
2. Avoid PVC and thermocol where another material works.
3. Use the thinnest film that does the job. Thinner film that holds is still less plastic.
4. Use paper where paper does the job well, such as void fill, wrapping and cushioning.

We make plastic packaging, and we are proud of it. But I would rather you buy the right plastic, and less of it, than the wrong one in bulk.

If you are not sure what your current packaging is made of, send us a photo and a sample. We will tell you which family it is from and whether there is a simpler option.

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