science

In-mould labelling

In-mould labelling is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand In-mould labelling rather than just read about it. In short: In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item.

Key takeaways

In-mould labelling belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect In-mould labelling to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of In-mould labelling from memory before moving on to harder problems.

Reference excerpt

In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item. Combining the decoration process with the moulding process cuts the total cost, but can increase the manufacturing time. The technology was first developed by Owens-Illinois in cooperation with Procter & Gamble to supply pre-labelled bottles that could be filled on the product filling line. This was first applied to Head & Shoulders shampoo bottles.

Principles In-mould labelling (IML) was initially designed for blow molding, though developments using injection molding or thermoforming with reel-fed systems have increased the efficiency of the labelling process. The original concept involves coating the reverse side of the label with a heat seal layer, followed by a substrate material which heat resistant ink is applied to. A heat resistant coating of lacquer is then applied. This process eliminates the need to flame treat the bottles prior to labelling in order to achieve adequate adhesion. Initially, paper was used as the label substrate to which the heat reactive adhesive was applied. In more recent times polyolefin substrates have been employed, such as Polyart from Arjobex Synthetic Papers. This creates the advantage that scrap polyethylene and polypropylene bottles produced in the molding process can be recycled, without the need for label removal prior to recycling.

Labelling There are several techniques for conducting the in-mould labelling process. Vacuum and compressed air can be used to handle the labels, also static electricity can be used. Electrostatic charging electrodes charge a label while it is being transferred to the moulding machine, so that when the label is placed on the tool and released by the labelling robot, it will wrap itself onto the tool. Most robot systems for placement of labels are not required for specific moulding machines and can be used with up to date presses with fast clamping systems. Labels may be paper or a similar material to the moulded product. Polypropylene or polystyrene is commonly used as label material, with a thickness of 15 to 40 micrometres. Cavitated label material is also used. This is a sandwich material, having a spongy layer bonded between two very thin solid layers. An advantage of cavitated film is better conformance to small-radius curves on a product. Laminated film can be used to decorate products, yielding high wear-resistance. This type of film has the printed surface protected by a second layer of film, with a thickness of 30 or 40 micrometres. Products using this type of label might include picnic-ware, mouse-mats, or internal automotive components.

Use In-mould labelling is a popular method of decorating injection molded parts for consumer electronics and for plastic bottles. Notebook computer and cellphone manufacturers are adopting IML technology for greater wear resistance than spray painting or pad-printing. IML can provide greater decorating options than other methods. Multi-color screen printed and offset lithography printed graphics are used to produce products with higher quality graphics than available with other decorating methods. Most applications in this area use second surface graphics. The decoration is printed on the back side of a clear substrate, typically polycarbonate or acrylic 0.125 to 0.375 mm (0.005 to 0.015 in) thick. In-Mold Labeling can combine with all substance surface after 2025 with the new chemical of pigment and special corona electric static Ref The injection plastic is on the ink side of the film. This encapsulates the decoration between the film layer and the injected plastic resulting in a decoration that cannot be abraded during use. Vision systems can check for accurate label positioning, and can validate label correctness.

See also In-mould decoration Plastic injection molding Case study

References

Worked examples

Example 1 — a first encounter with In-mould labelling

Start with the simplest possible case. Write down what In-mould labelling claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to In-mould labelling before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about In-mould labelling ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of In-mould labelling

In research: In-mould labelling appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses In-mould labelling in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: In-mould labelling is common in secondary-school and first-year university syllabi. It links to neighbouring topics Labels, Packaging, Plastics industry, so understanding it makes those chapters shorter.
In everyday life: Look for In-mould labelling outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study In-mould labelling in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what In-mould labelling means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain In-mould labelling out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is In-mould labelling in simple terms?

Why does In-mould labelling matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study In-mould labelling?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on In-mould labelling.