Physical Analysis: Putting Cosmetics Packaging to the Test

The development of cosmetics for release into a competitive market is a high cost endeavour, so it would be inefficient for these high stakes products to be shipped in low quality packaging, or for the container to degrade during its shelf life.

Packaging is the first thing the customer sees in the shop so from this point of view the graphics and physical design are important to make it stand out amongst other similar products; the appearance of packages can directly affect marketing. However, the main purpose of packaging is to ensure the product arrives in a customer’s hands in perfect condition and to prevent any losses caused by shipping, handling or storage.

Will the package protect its intended contents?

This is the first question to be answered during this series of tests. The majority of obstacles faced by a product can be imitated using physical testing with a Texture Analyser. Any given company will have a standard set of tests for new products or for spot checking the quality of products already on the market. Physical testing measures the strength of each component and joint, assessing whether or not the container will continue protecting its contents after shipping or a long storage time.

Shipping can be imitated using force cycle tests to represent the repeated loading the product will face during its journey, whereas storage testing may involve a timed compression with a large platen to mimic the action of stacking many products on a shelf. Bottle tops are widely-used and the strength of the cap itself is an important measure, as this influences the transportation restrictions. Points for consideration include the worst case scenario a package may face, and what the cumulative effects will be of days of shipping or months of storage amongst other packages, or even in a cosmetics drawer in the consumer’s home.

The absolute material strength of a product is an important part of this testing process. For instance, adhesives are widely used in cosmetics packaging, particularly in a seam at the edge of a sachet. These are assessed by performing a T-peel test on a small section of the sachet joint. The customers’ safety must also be considered, and this is relevant when testing a property such as the puncture strength of an aerosol deodorant can.

Packaging tests will cover either the whole assembly (a whole lipstick tube), one part of the packaging (the lid of a hairspray) or a sample of the material itself (a dogbone specimen of a plastic used for a talc bottle).

Is a package still attractive and functional after physical testing?

A customer might have found a lipstick they adore and have carried it around in their coat pocket for months, but the lipstick is nearly out and the plastic has started cracking at the fragile lid opening, causing the brand to appear to have skimped on packaging costs. In this case the fragile lid should have raised a red flag during testing and been reinforced with an alternative material.

Many cosmetics are integrated with their packaging, so the packaging also acts as a dispenser or applicator. For example, the applicator brush in a mascara tube is both a component of the lid and a crucial part of the application process. For these products, their functionality may be tested after the ageing or shipping tests have taken place.

Towards the end of its useful life, what experience will the consumer have of the packaging? Testing can help to predict whether it will still be functional or if it will start falling apart, and this quality assurance goes a long way towards helping the product designers tweak the design.

Is a container easy to use?

The forces involved in using a product must be within a suitable range for any customer ability in the intended market. For any given action (such as pulling, snapping or pressing) an acceptable range of forces can be determined by referring to tabulated results of the forces a child, healthy adult, elderly or infirm customer is capable of. The product container can then be tested in a quantitative way on a texture analyser, and the forces verified. For example, if the lid of a tub requires a high force to remove, it may be too difficult for some customers to use that product without assistance.

Adhesives are widely-used in cosmetic packaging. A pressure sensitive adhesive that may be found on a film lid to seal a face cream could either be tested alone using a ball probe compression-tension cycle, or a peel test could measure the real force required to remove the lid at a 90 or 180° angle.

Another commonly-used packaging method is the polymer-based sachet. In this case the ease of opening is determined by the tearing force, strength of seal (from the hot press process) and friction of the material surface. When a consumer is opening the package, if the friction does not match with the tearing strength, they cannot get enough grip on the package for a high tear force and it will slip in their hands. In this case all of these properties should be tested individually by machine and verified using a sensory panel.

Is the container compatible with its contents?

This question is answered using packaging compatibility tests. These tests are carried out on everything that is destined to go into production, simultaneously with stability tests, which were outlined in a previous blog post. If a formula is not appropriate for the intended container type, if the combination of container and closure is inadequate or if the packaging is poorly made, the compatibility test will catch it out. Occasionally a test as simple as having the formula in containers made of different materials will give very different results of the contents’ stability.

Weathering and ageing tests are often used to speed up the degradation process, especially when the product may be stored in extreme temperature environments. Heated cabinets with temperature control are the standard piece of equipment used in this case. A container is filled with its formula and heated to a specific temperature for a given time period. Once this ageing is over the container is taken back to the Texture Analyser and its physical properties are tested once again, along with an assessment of decolouration, weight loss of the contents and stress cracking.

Summary

Exponent software is extremely valuable to this type of testing as standard projects can be saved to enable each set of test settings to load at the press of a button, along with automatic data analysis and report generation. A wide variety of international standards can also be built into the software. With data appearing graphically on-screen in real time, the suite of Texture Analysers along with their expert software is ideal for use in quality control.

To find out how we can help you improve customer satisfaction and loss reduction with a custom set of packaging tests, talk to Stable Micro Systems today.

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We can design and manufacture probes or fixtures for the TA.XTplus texture analyser that are bespoke to your sample and its specific measurement.

Once your measurement is performed, our expertise in its graphical interpretation is unparalleled. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can also prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

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