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Colour Match

Can you imagine a life without colour? It would be pretty dull, wouldn’t it. Colour is an essential component of all our visual experiences – it has the ability to represent and evoke certain emotions, and it plays a pivotal role in our ability to recognise brands and familiar objects instantaneously. Without even realising it, colour can affect our behaviour – if we see a green banana, we know it isn’t ripe and choose not to eat it, if we see a red light, we know to be cautious or stop.

But why is colour accuracy important?

  • Colour increases brand recognition by up to 80%, so brands use colour to reinforce their identities. A brand’s choice of colour is a fundamental element that represents both its personality and the qualities of the products and/or services it offers.
  • Colour variance is detrimental to perception of quality. This can be determined from low grade pigments or variance in process and that’s why colour management is so important. We rely heavily on colours to guide us, sometimes unconsciously, so it’s imperative we get it right, every time.

How do you achieve colour accuracy in the plastics industry?

Properly dispersed pigments are crucial to the manufacture of high-quality and accurate colour dispersions. Without the proper dispersion of pigments, the colour will not hold up and maintain the expected colour standards. Pigments are insoluble particles that impart colour to PVC (plastisol) and other materials. The correct selection of specific pigment and additives to specified applications and environments is vital to ensure the finished colour dispersion used to colour the coating effectively is accurate. There are different ways that pigments are dispersed in plastisol materials. Therefore, understanding the properties and chemistry of the pigment is vital for knowing how it will be distributed.

Here are some of the essential properties that are required for good pigment dispersion…

Viscosity

Another significant factor for colour dispersion and coatings additives is consistent thickness of the dispersion. Flowable pastes with a lower viscosity will ensure better distribution of pigment dispersions throughout the plastisol, however the suspension of the pigment particle is critical for shelf life for repeatable results.

Stability

The lightfastness or permanence of a pigment is its resistance to change on exposure to light. This depends on the chemical nature of the pigment, its concentration, and the medium in which it is carried. Pigments need to be chosen that have good lightfastness in order for the plastisol coating to have a resounding and vibrant colour that does not fade with time or in sunlight. High levels of lightfastness stability can be specified from general to high level pigments. Pigments must also be chemically and physically stable and must not break down or change in any way as they age. Pigments must also be selected carefully for weather fastness where long-term colour stability is required.

Brightness of Hue

The pigments used in colour dispersions for plastisol coatings manufacturing are usually chosen for their bright hues. When formulating a gloss finish coloured PVC plastisol, the pigment selection and other additive ingredients in the dispersion must not affect the high glossy finish of the PVC in order to achieve and maintain the greatest vibrancy of colour.

Particle size

A crucial aspect to understand about the dispersion of pigments in a carrier is the size of the pigment particles. Smaller particle size of pigment generally provides better transparency. More importantly, the finer the grind of the pigment the greater the colour strength that can be achieved from a given quantity of pigment. This can either lead to stronger shades or, given that the pigment is usually one of the more expensive components of a plastisol, it can make the formulation more cost effective.

Naturally the newly obtained small particles have a tendency to re-agglomerate, causing phenomena known as “flocculation”. Uncontrolled aggregates and flocculates have poor influence on the colour dispersion quality and can reduce the coatings stability, reduce the colour strength and gloss, or change the plastisol’s rheology. Wetting & dispersing agents will prevent this unwanted effect and provide a long-term stabilisation.

Wetting & dispersing agents

Bright, vivid and durable colours are one of the most important parts of the coatings’ aesthetic definition. In order to achieve a desired colour for the coating, formulators are using more technically advanced pigments. But keeping these solid particles stable in a liquid is a complex mechanism which includes the wetting and dispersing of the pigment to maximise colour strength as well as the stabilising of solid particles in the colour dispersion system. The selection of wetting / dispersing agents (surface active chemical) requires expert selection to ensure compatibility with both organic and inorganic pigments for use in a colour dispersion for various coatings systems and applications.

Polyblend’s collaborative approach to understanding the customer requirements such as by specifying the specific shade, strength and stabilisation needed to suit the application and its environment is key. Our colour matches are designed through a powerful and accurate colour matching software system linked in support to our spectrophotometer. The industry-specific application optimises the quality of the formulation with superior first-shot matches to streamline all our colour process with one complete solution.

If you want to find out more in how to bring your product’s colours to life and add value to your product range then please reach out to me on here for more information on how Polyblend may be of help!

 

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