Blue Oxide Pigment Applications
Blue oxide pigment - from African Pegmatite - is a persistent and long lasting colourant for a wide variety of scenarios, providing a stable depth of colour for the most demanding applications. Combining a wide reach, specialist knowledge and in-house milling capability, African Pegmatite is the preferred industrial partner.
What is Pigment?
Briefly, a pigment is a substance that causes a change in a reflected or transmitted light which results in a selected absorption. This process is known to be physical and completely differs from fluorescence and other substances where the emission of light occurs.
Depending on the type of pigment, certain wavelengths absorb light. And the consisting properties make them useful in coloring materials. The reason behind this is that the coloring power is high compared to the materials used in painting. These materials are insoluble and should not be mixed with binders or carriers. Furthermore, pigments are specially used for art paintings, car finishing and reflective panels. The reason as to why pigments are better than any other product is that they continue to have their color for more than a century. Also, they are highly resistant to heat, light, and weather including chemicals.
What Is Blue Oxide Pigment?
The colour in blue oxide pigment arises from finely milled copper phthalocyanine and is a member of the phthalocyanine dye family. Chemically interesting, copper phthalocyanine is a coordination compound with a central Cu2+ with the conjugate base phthalocyanine. Pure copper phthalocyanine is poorly water soluble. As mined, the blue pigment contains moderate quantities of lithium, calcium and aluminium oxides. As supplied from African Pegmatite, blue oxide pigment is milled to 90 to 95% smaller than 75 µm - rendering it easily dissoluble in a variety of solvents and media. In excess of 25% of modern synthetic dyes are derived from phthalocyanines. The first synthetic phthalocyanine was produced by accident in 1907 as an unidentified blue compound(1). The vivid blue colour is due to a π to π* transition at a wavelength of around λ = 610 nm.
Blue oxide pigment - specifically copper phthalocyanine - goes by several names, including: phthalocyanine blue, monastral blue, helio blue and windsor blue, amongst others. A related dye, ‘phthalocyanine green G’ is readily produced by chlorinating copper phthalocyanine in the presence of aluminium trichloride.
Stability and toxicity
Known for its long term pigmenting ability without fading and weather fastness, blue oxide is an appropriate choice of colourant for a wide range of applications. This is further illustrated by its good levels of resistance to heat, acids and bases. These open up the use of blue oxide pigment to a wide variety of uses, as discussed below, in plastics, cements, paints and more.
In terms of toxicity, neither copper phthalocyanine or any of the other components are harmful to human/animal, marine or plant life. Copper phthalocyanine itself has an LD50 value of 5 g kg-1 and there is no evidence of it being a carcinogen. As will be discussed later, blue oxide is used in such low quantities in most applications, there are no health concerns.
Applications of Blue Oxide Powder
Colored roof tiles bring a unique roofing work. In the usage of roofing, the pigment is important when considering the quality of the final product. Also, the color combination is crucial since it becomes exposed to different climatic changes. To avoid the risks the blue pigment oxide is used to provide color to the tiles since they have high quality when it comes to strength and color consistency and helps in providing UV protection.
In the structural and civil engineering sector, concrete plays an important role because the modern world would not have been the same without concrete. Examples like the yellow-pigmented Antión Bodega in La Rioja, Spain or the Arsta Bridge in Stockholm would not have been recognized around the world, if not for the ideal color combination. The reason behind the success of the construction is the blue oxide pigment which carries high quality in terms of strength and color consistency.
And the product contains a wide variety of colors and shades such as yellow, red, green, glossy and brilliant shades. Pure colors like yellow can be easily made using white cement but producing shades is not easy due to the difficulty in the composition and structure of the concrete.
Moreover, colored paving stones brighten up places like parking lots, bicycle paths, decking slabs in pedestrian zones by breaking the dullness of the surface. After the quality of the products was proven, pigments are widely used in adding color for paving. These products are highly weathered stable thanks to the chemical structure. To get a successful two or multi-color effect, colored concrete must not be mixed. Also when it comes to the choice of pigments, prominence should be given to the quality of the end product. The tests that were run on colored concrete products based on climatic changes, it has been widely accepted that inorganic oxides show good fastness properties. When two or more concrete slabs are mixed, one of the colors gets emphasized. Hence the differing production procedures become possible depending on the availability of machinery.
Paint is a liquefied substance that is used to protect color and texture of objects. It can either be watercolor or synthetic. Generally, paint is stored and sold in a liquefied state but with time most of the types get solidified.
The paints used for the exterior walls should be high in weather stability than the paints used for the interior walls because the exterior walls are more exposed to intense sunlight and should be given protection to save from getting damaged. However, light fastness plays an essential role in interior walls as well since they can also be exposed to intense sunlight. Depending on the binder, emulsion paint uses “water” as the solvent and a small amount of coalescence agent is needed to merge the elements to form a whole.
But certain paints in the modern world that have neutral order and are environmentally friendly, they do not need any coalescing agents to merge the mixture. In designing the living space and coloring of interior walls, beauty and good taste play an important role. Henceforth as a reason to esthetics, pastel colors are favored.
A roof coating is a fluid applied to the roofing membrane to avoid heat waves. And to make it work, the Blue oxide is added. Also, most of the roof coatings show elastic properties that enable them to stretch and return to their original state with zero damage. The reason to consider the roof coating to be important is that it is the topmost layer which protects the membrane avoiding sunlight, infrared and ultraviolet rays, rain, etc.
One of the most prolific deployments of copper phthalocyanine colourants is as the primary choice for locomotive and coaching stock paint from 1965 through to the 1990’s in Great Britain, known as ‘rail blue’ - further providing evidence of blue oxide’s long lasting pigmentation persistence.
In day to day life, commodity articles that can be bought and sold are made from plastic. The pigments that are used to color plastics must meet several demanding technical and qualitative requirements. Due to the short lifetime and low shear forces, the pigments must be good in dispensability. Their thermal stability should be high and must be easier to break down so the final tinting would strengthen quickly. And most importantly light fastness and weather stability need to be adequate and should avoid getting migrated.
Special oxide pigments are developed to fulfill higher requirements. Most of the pigments are micronized and as result agglomerates are reduced. Before demanding the applications, a serious pre-testing should be undertaken to test the quality. Blue oxide pigment is supplied as a fine powder and as a low tendency to agglomerate.
Green pigments have perfect resistance properties such as heat stability, migration resistance, light fastness, and weather stability. Fortunately, these pigments are capable of coloring any type of plastic and should have high inherent hardness when dispersing these pigments. Moreover, this can be significant if used in high- speed mixers like when mixing PVC powders etc. And in such cases, metal elements can be subjected to more damage due to the hardness of the pigment.
To gain a successful saturated green, chromium oxide green pigments can be mixed with bright yellow pigments. And they are used in the technology sector to color engineered plastics for machine components.
When being used for the production of plastics - particularly those intended for use in the medical space - it is crucial that the pigment is easily distributed (which is a product of how easily it is to crush and thus powder into a uniform particle size - something blue oxide achieves easily) and it has good long term stability, particularly to organic solvents, acids and bases.
Research has shown that only as little as 1% by mass of the pigment is needed to sufficiently colour polyethylene a rich blue colour. Authors also subjected the resultant blue plastic to a machine that synthetically weathers materials for over 2,000 hours - finding no degradation of material strength or colour intensity over that time(2). The researchers also reported that the phthalocyanine blue provided more UV protection than ultramarine blue by two to three times.
Since water is a colorless liquid, multiple wavelengths of light that are being absorbed and reflected off the water create color. Electrical signals are formed in the brain with the processing of light wavelengths through the photoreceptors in our eyes. Hence from individual to individual, watercolor is unique and is different from how the color is perceived by the brain.
Blue oxide is used to get the blue color in swimming pools. When designing the swimming pool, it is a must to focus on the finishing of the pool because it needs to stand up to a rough environment underwater. Also, the most used variables that influence the pool watercolor are the depth, size, surroundings of the pool, sunlight and any preconceived idea.
If a material is a pigment, it’s likely a dye too - logic suggests. Although perhaps a niche use, phthalocyanine blue can be used as a textile dye across a broad range of fibres, with a preference for natural ones such as cotton. It has been reported that phthalocyanine blue coloured fabrics have excellent colour intensity and colour fastness - but crucially are highly resistant to attack by acids and bases as well as oxidising and reducing agents(3).
- Blue oxide is a compound pigment based primarily on the copper phthalocyanine chromophore
- Also in the pigment are various oxides of iron, calcium, aluminium and others
- Blue oxide is insoluble in water, but mixes well in acids, bases, oils and cements offering a deep and persistent colouration
- In deployments ranging from paint to concretes to inclusion in plastics, the colouration provided by blue oxide is deep, long lasting and highly stable
Blue oxide pigment is just one of many pigments supplied by African Pegmatite - the leaders in mineral processing. With specialist in-house milling, a broad reach and an unmatched depth of experience, African Pegmatite is the go-to pigmentation partner.
1 J. F. van Staden, Talanta, 2015, 139, 75
2 L. K. Massey, High Density Polyethylene in L. K. Massey The Effects of UV Light and Weather on Plastics and Elastomers, William Andrew Publishing, Norwich, NY, United States, 2007
3 J. N. Chakraborty, Dyeing with phthalocyanine dye in J. N. Chakraborty, Fundamentals and Practices in Colouration of Textiles, Woodhead, New Delhi, 2014