FAQs – Masterbatch

LCR Hallcrest produce and supply a range of additive Masterbatches usually in pellet form, for addition into many polymers. Thermochromic masterbatch is temperature sensitive plastic, that changes colour with exposure to heat or cold. It can be added to many polymers to make a wide range of applications. Photochromic masterbatch reacts to UV and sunlight, and is semi clear when unactivated indoors or out of direct UV light and becomes coloured when activated by UV light or sunlight. Glow-in-the-dark masterbatch glows when in the dark, after first being sufficiently exposed to sunlight.

What plastics can I add colour changing masterbatch to?

Softer polymers are better. Polypropylene, polystyrene, HIPS, EVA, HDPE, ABS, PVC, PU, TPU, TPE.

Can I use it for injection moulding, extrusion or even blow moulding?

Yes.  Injection moulding is the most commonly used process for these masterbatches.

In addition to pellets, we can also supply in free flow powder on request.

Do they change colour many times?

These are reversible masterbatches, which change back to their original colour when the conditions are reversed.  The colour change can then be repeated time and again.

We have also created a special  ‘Quasi-Irreversible’ Thermochromic type, where the colourchange can be ‘locked in’ under certain temperature conditions.

How do I use it ?

Masterbatch pellets can be dosed into the main polymer at around 3% to 5% let down addition rate, depending on the colour strength required.

Also, the thicker the plastic item being moulded, the stronger the colour will be.

Moulding or Extrusion temperatures should be kept under 220°C including during heating in the barrel.   Keep dwell times short, to avoid damaging the masterbatch.

Should I use a clear plastic?

Yes. Always use the clearest plastic possible; this will result in the best final colours.

Can I use a white plastic?

Yes, but it will make the final colours much paler, like adding white paint to a coloured paint.

Can I mix the colour-changing masterbatch with a standard/normal masterbatch colour?

No, not if this is a ‘solid’ colour, because it will overpower the colour changing colour.
Yes you can mix Thermochromic masterbatch with a fluorescent masterbatch because this is semi opaque, and does not overpower the colour changing masterbatch.
Photochromic masterbatch does not mix well with other colours as this partly affects the uv colour change, and is best dosed in on its own.

How does thermochromic masterbatch work?

Thermochromic masterbatch reacts to changes in temperature by changing colour. It is always a darker colour when colder, and a lighter colour when hotter.

What temperatures are availablein Thermochromic masterbatch?

Our standard temperatures are 19°C, 30C/31°C, 38C and 41°C.  Other temperatures from -15C to +69C can also be created, with higher minimum order levels. Please ask for further details.

 

What colours are available in Thermochromic masterbatch?

Standard colours are blue, red, magenta and green. Other colours can be created but with a higher minimum volume and cost per kilo. These could be black, brown, purple, orange, and turquoise for example. Or other colour to colour options.

Does the masterbatch start white or a lighter colour, and then the darker colour appears?

Thermochromic masterbatch is always a darker colour when colder, and a lighter colour when hotter. Available as either a single colour, or colour to colour.

i)                Single colour:

For a cold reaction, this is semi white at room temperature and becomes coloured (ie blue) when the temperature drops below the masterbatch’s activation temperature, and back to semi white when warmed above this temperature.  For a hot reaction, this is a colour at room temperature and becomes semi white when warmed above the masterbatch’s activation temperature, and back to the colour when the temperature drops below this temperature.

ii)               Colour to colour:

For a cold reaction, this is a paler colour at room temperature (ie pale pink) and becomes a darker colour when the temperature drops below the masterbatch’s activation temperature (ie purple), and back to the paler colour when warmed above this temperature. For a hot reaction, this is a darker colour at room temperature and becomes a paler colour when warmed above the masterbatch’s activation temperature, and back to the darker colour when the temperature drops below this temperature.

Can I add more colours into one product?

Yes, we can create a triple colour thermochromic masterbatch, where each colour appears at a different temperature.  Please ask for further details.

Is this masterbatch phthalate-free and BisPhenol-A (BPA) – free?

Yes.

Is it food contact safe?

Thermochromic masterbatches have been frequently used in food contact items such as spoons and drinking straws and have passed EN71-3 independent testing and TUV food contact testing, however we would recommend thorough testing of the particular item containing the colour changing masterbatch.

Can I print onto the products?

Yes, depending on the type of base plastic used. Pad/tampo printing is the most popular method.  PP will need heat treating prior to printing, in the normal way.

Can colour changing masterbatches be used in outdoor products?

We do not recommend thermochromic or photochromic masterbatches for prolonged outdoor applications as U.V. light rapidly affects the colour change if a product is left in continual UV for a period of time.

How can I get hold of some of this masterbatch?

We can supply a 100 gm ‘sample pack’ of a few specific variants (ie blue at 19°C, magenta at 31°C and red at 47°C)

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