Pigment Green 7 (PG7) is one of the most popular phthalocyanine green pigments in the world, and one of the most widely available. However, there’s still plenty of confusion about why it does what it does when exposed to air – this article aims to clear up that confusion!
Colourants Do Not Normally React With Air
If you are a regular on our Facebook page, you would have noticed a very intriguing response we gave to one of our fans. A plastic pigment manufacturer asked us how pigment green 7 changes colour with exposure to air. We left curious about it and decided to do some research and share it with you here. Keep reading! Pigment Green 7 an organic pigment manufactured from petroleum by products such as benzene and cyclohexane. It considered a plastic pigment since it is manufactured in an organic solvent environment using certain chemicals like phthalic anhydride, phthalic acid etc. As mentioned above, Pigment Green 7 contains no metals in its chemical structure which makes it more stable than other pigments like Iron Oxide Red (Fe2O3) or Cobalt Blue (CoCO3).
This means that there is no reason for the green pigment to change colour with exposure to air or moisture. However, if any impurities like water are present during the pigment manufacturing process then it may cause slight discolouration of pigment green 7. For example, if water used as a reaction medium instead of alcohol then slight discolouration occur due to the formation of the OH group in a water molecule. Similarly, a small amount of moisture content found during the pigment manufacturing process due to the presence of reactive solvents like benzene and cyclohexane. But these impurities not affect much due to the use of high purity raw materials by pigment manufacturers in Gujarat India. So why does Pigment Green 7 change colour with exposure to air? There something else at play here!
So Why Does Pigment Green 7 Turn Yellow In The Tube?
Plastic pigments like Pigment Green 7 are made of synthetic organic chemicals that have been designed specifically for industrial use. Organic chemistry deals with carbon and its chemical properties, hence organic means anything with a carbon-containing molecule. Though these plastics used in consumer items like cosmetics, toys and clothing, they generally not made from edible materials or found in food. When you see an image that contains pigment green 7, it is usually safe to assume that it is either a plastic pigment or an acid-base indicator like litmus paper—both of which little effect on human health if exposed occurs.
Pigment Green 7 itself can be toxic if ingested, but only at levels above 100 mg/kg body weight. If pigment green 7 changes colour as soon as it’s exposed to air (as many pigment manufacturers will claim). then it likely because of oxidation reactions between molecules within the paint. The reaction releases hydrogen peroxide (H2O2) into your environment and H2O2 will cause all sorts of colour changes depending on what else is present in your environment. Depending on how much H2O2 released into your paint container, any number of colours could appear depending on what other molecules are around at the time.
What Makes This Pigment Turn Yellow Over Time?
The yellowing occurs in both organic and inorganic plastic pigments (which include pigment green). The chemical compound responsible for turning them yellow is benzoic acid. It exists as white crystals, but it becomes airborne and reacts with other chemicals (even plasticizers from PVC pipes) and/or heat to become oxidized. There are methods of stabilizing pigments which will extend their useful lifespan. Pigment manufacturers in Gujarat may be able to help you here.
However, since Pigment Green 7 is a cheaper alternative to safer pigments like Pigment Blue 15:3 or 19:3, there’s not much incentive for manufacturers to go through all that trouble. To ensure your safety while using these types of products – including paint – make sure you have adequate ventilation or use a respirator mask while working with them. As always, contact your doctor if you experience any health problems after exposure to plastics or paints. We hope that helps!
How To Use Pigment Green 7 Effectively In Products?
One of our pigment manufacturers in gujarat has developed a range of eco-friendly products using pigments. The products processed using an innovative, environmentally friendly process. Our pigment green 7 mixed with other dyes for a variety of uses: for cosmetics and creams, for PVC plastic and printing inks. It also used on its own as a food colourant that is suitable for dairy products and confectionery. For example, it is ideal for colouring jellies and gums such as chewing gum or bubble gum, as well as marshmallows, chocolate and many more sweet treats! By adding our pigments to ice cream or yoghurt, your customers will be able to enjoy attractive shades of green while staying healthy. Why not try some out today?
