Chromium oxide green used as coloring

Cosmetics / Drugs：

FDA Drugs - Approved for use as a coloring agent indrugs for external use only in an amendment to the Food and Drug Regulations, Schedule No. 846, Department of National Health and Welfare, March 11, 1995.

Food Contact：

21CFR 178.3297 - Approved for use as a colorant in all polymers intended to contact food, at a level not to exceed 5% by weight. Listed under 21CFR 178.3297.

Resolution:

AP(89)1 - Council of Europe AP(89)1 Approved Pigments - migration of the elements antimony, arsenic, barium, cadmium, chromium, lead, mercury, and selenium from the following pigments are typically below the limits set forth in the Council of Europe resolution AP(89)1 on the use of colourants in plastic materials coming into contact with food, 13 September 1989.

AS2070-1999 - Australian Standard AS 2070-1999 Approved Pigments - migration of the elements antimony, arsenic, barium, cadmium, chromium, lead, mercury, and selenium from the following pigments are typically below the limits set forth in the Australian Standard AS 2070-1999, Plastics materials for food contact use (4.1.2 Colourants), published 5 March, 1999.

BfR IX - List of the BfR Approved Pigments: Pigments are not regulated by the Bundesinstitut für Risikobewertung (BfR) unless they contain dangerous substances.
FCN-Approved for use as a colorant in all polymers intended to contact food.Listed under FCN 1839.
GB9685 : 2016 - Pigments typically meet the purity requirements set forth in the National Food Safety of the People’s Republic of China, GB9685-2016 Standard for Uses of Additives in Food Contact Materials and Articles. Please see GB9685:2016 document for limitations.

Recycling:

CONEG - The following pigments, when used at a 25% maximum, typically contain a sum total of the regulated metals lead, cadmium, mercury, and hexavalent chromium below the strictest specification of 100 ppm set forth in the Model Toxics in Packaging (CONEG) legislation.
94/62/EC - The following pigments, when used at a 50% maximum, typically contain a sum total of the regulated metals lead, cadmium, mercury, and hexavalent chromium below the strictest specification of 100 ppm set forth in the Council of Europe Directive 94/62/EC, on packaging and packaging waste.
RoHS - The following pigments meet the purity thresholds for lead, cadmium, mercury and hexavalent chromium as specified in European Directives for the End of Restrictions on the use of hazardous substances in electrical and electronic equipment (RoHS).
ELV - The following pigments meet the purity thresholds for lead, cadmium, mercury and hexavalent chromium as specified in European Directives for the End of Restrictions on the use of Life Vehicles (ELV).
WEEE - The following pigments meet the purity thresholds for lead, cadmium, mercury and hexavalent chromium as specified in European Directives for the End of Restrictions on the use of Waste electronic and Electrical Equipment (WEEE) as they are currently written.

Toy Safety:

EN 71-3：2019+A1：2021 - The European Committee for Standardisation (CEN) has introduced an Element Migration Class Act for child contact products. Some of our chromium oxide green can meet this standard.

Imaging spectroscopy can obtain the spectral characteristics of a target while imaging it, and can be used for military reconnaissance to identify the difference between the spectral characteristics of a military target and the background environment. In other words, this technology makes the spectral signal different from the environmental background of the military target is completely exposed to its field of vision. In today's information war background, to be found means to be destroyed, imaging spectroscopy technology makes the military target's survivability is seriously threatened. In order to cope with this threat, military targets need to be close to the background environment in the wavelength range to be detected "the same colour and the same spectrum", that is, not only has a similar colour, but also has similar spectral characteristics. Usually, military targets on the ground mainly use green vegetation as the camouflage background, so it is of great significance to find and study bionic materials that can simulate the spectral characteristics of green vegetation and apply them to military camouflage to enhance the survivability of military targets.

So far, through the unremitting efforts of researchers, the existing high-performance camouflage coatings and devices in terms of colour, pattern, brightness and other aspects can be achieved with the green vegetation background fusion and matching, basically eliminating the military target in the visible wavelength band of the colour and outline characteristics, and basically achieved in a certain wavelength range and the approximation of the spectral characteristics of the green vegetation, which can be effective in deceiving the conventional imaging reconnaissance, but in the visible near-infrared region (visible) and the green vegetation (visible) and the green vegetation (visible) and the green vegetation. However, its fine reflectance spectrum in the visible near-infrared region (400~2,500 nm) still differs greatly from that of green vegetation.

Chromium trioxide Cr2O3, also known as chromium oxide or chromium green (Pigment Green 17, PG17), is available in two crystal types, α-Cr2O3 and γ-Cr2O3, of which α-Cr2O3 is the thermodynamically stable crystal type. α -Cr2O3 is corundum structure, belongs to the hexagonal crystal system, O2- in the crystal lattice is hexagonal dense accumulation, Cr3+ in these hexagonal dense accumulation of octahedral gaps, forming six-coordinated [CrO6]2-, similar to the octahedral field. Due to the overall electroneutrality of the crystal, only 2/3 of all octahedra are occupied by Cr3+. The visible near-infrared spectral reflectance properties of chromium oxide are mainly affected by the electronic orbital energy levels of Cr3+. The electron arrangement of Cr3+ is [Ar]3d3. Ideally, the five d-orbitals in free Cr3+ are merged without taking into account the ligand field effect and d-electron interactions. In fact, due to the mutual exclusion of electrons, the three electrons in the d-orbitals have different energy levels (different spectral terms), and the base spectral term 4F can be obtained for the d3 group state according to the Hund's rule and Pauli's principle. Moreover, the base spectral term splits further in the presence of the ligand field. In the octahedral field, the F term can be split into three spectral terms with different energies, 4A2g, 4T1g, and 4T2g. There are two transitions between the quadruple states of chromium oxide: 4A2g→ 4T2g and 4A2g→ 4T1g, which correspond to the two absorption bands in the UV-visible absorption spectrum of chromium oxide at 430~500 and 580~670 nm, respectively. It is because these two groups of jump absorption bands and chlorophyll porphyrin ring two groups of molecular orbital jump absorption bands in the same location, absorbing the energy of the visible region of the blue light and red light, but almost no absorption of the wavelength region of the green light, resulting in the formation of chromium oxide reflectance spectral curve around 535 nm corresponding to the reflectance peaks, close to the "green peak" position of the green vegetation. " position near the green vegetation.