Posted on July 24, 2017
Tinted Sunscreen Manufacturing Is a Difficult, Delicate Process
Sunscreen can be a difficult mix to master. Sunscreen recipes vary1 by color, SPF level, brand, and intended usage. Further, as consumers become more wary of synthetic products, sunscreen manufacturers have needed to alter their recipes with more natural ingredients. Adding to the complexity of the process is the number of ingredients. Sunscreens are made of purified water, emollients, lubricants, emulsifiers, thickeners, perfumes, colorants, preservatives, and UV filters and absorbers.
In order for tinted sunscreen to come out the right color, all these ingredients must be added in a precise order, at the correct ratios, and mixed without error. In the case of tinted sunscreen, mix color homogeneity is linked to brand consistency. As the color of a company’s sunscreen is its major selling point in the high-end consumer cosmetics market, inconsistent mixes and off-color sunscreens can drive away customers. That’s why tinted sunscreen manufacturers need to get it right before their product is ever bottled.
This is easier said than done. Sunscreen is either an oil-in-water or water-in-oil emulsion. Even when properly heated, this blend does not always easily mix, often requiring extended processing times. Powdered ingredients increase this difficulty, as they do not always dissolve entirely, and can stick to the sides of the mixing vat as residue. These process difficulties can result in off-color batches. Without careful attention and stringent quality control, it is entirely possible for sunscreen manufacturers to bottle and ship an inaccurately colored product.
Spectrophotometric Quality Control Allows Manufacturers to Adjust Sunscreen Batch Color
For this reason, sunscreen manufacturers employ spectrophotometers—instruments which objectively analyze color—to determine if their mix meets standards. Manufacturers program a tolerance standardbased on their desired tint into the instrument. Then, by periodically testing samples against this standard, technicians can simply and accurately determine if a batch is the right color. Implementing this process allows manufacturers to make any needed changes to off-color batches, such as prolonging the mixing cycle, before the sunscreen leaves the vat. To test batch homogeneity, the results from many samples from the same vat can be compared to one another.
These instruments are far more effective than relying on human observers for color quality control. Unlike human observers, they have no problem identifying tiny differences between similar shades. By measuring the reflections of a controlled beam of light, they are able to determine the exact shade of opaque liquids or solids with decimal precision. The processors built into these instruments render color as a series of numerical values that can be communicated and replicated. This eliminates the need for printed standards and the fuzzy borders of subjective color standards.
With over six decades of experience developing color measurement instruments for a wide variety of industries, HunterLab has learned how to help manufacturers efficiently, affordably, and easily improve their quality control processes. To learn more about how spectrophotometers help keep sunscreen the right tint,
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