Industrial grade 99%,Iron oxide brown CAS 1332-37-2

What is iron oxide brown? What are its uses?

1. What is iron oxide brown?

Iron oxide brown, also known as iron brown or brown iron oxide, is a brown inorganic pigment made by blending iron oxide red (Fe2O3), iron oxide yellow (FeOOH), and iron oxide black (Fe3O4) in different proportions. It is one of the most widely used varieties of iron oxide pigments. Its composition can be described as follows:

Fe2O3·FeO (a mixture of iron oxides, CAS No.: 52357-70-7; synthetic iron brown is a mixture of iron red, iron yellow and iron black)

It is a brownish-red powder at room temperature, non-toxic and odorless, with high coloring and hiding power, stable chemical properties, and resistance to light, alkali, heat, and weathering. It can absorb almost all ultraviolet wavelengths, thus exhibiting excellent resistance to ultraviolet aging. Natural iron brown often contains dopants such as carbon and manganese oxide, while synthetic iron brown is a blend of iron black, iron red, and iron yellow, with pure color, stable quality, and good reproducibility.

Structurally, iron oxide brown inherits the characteristics of three iron oxide pigments: iron red (red hue), iron yellow (yellow hue), and iron black (black hue). It has a wide color range, and various brown shades from light brown and reddish brown to dark brown can be obtained by adjusting the proportion of the three components. Its hiding power and tinting strength are superior to those of single iron oxide pigments.

Chemically, iron oxide brown is a stable inorganic pigment with good acid and alkali resistance. It is insoluble in water and organic solvents, does not migrate or bleed, and has good compatibility with cement, paint, plastics, and other base materials. It is gentle on the skin and has good compatibility with cosmetics and other base materials. It is one of the most internationally recognized families of inorganic colorants and has been approved by the US FDA, the EU, and other countries for use in food and cosmetic coloring. It should be stored in a sealed, moisture-proof container.

This product is graded according to its application field, commonly including: industrial grade (for coloring in building materials, coatings, plastics, rubber, etc., commonly specified by iron content and fineness), cosmetic grade (for coloring cosmetics, FDA approved), and food grade (for food coloring, regulatory approved). Different grades of products have different requirements for controlling heavy metals and other impurities, with a focus on the following indicators:

Tinting power and covering power

Tinting strength and hiding power determine the coloring effect and dosage of pigments, and are core indicators of pigment performance, directly affecting formulation costs.

2. Heavy Metal Limits (Lead, Arsenic, Cadmium, Mercury)

The most relevant indicator of safety for cosmetic and food grade products is to keep heavy metals like lead, arsenic, cadmium and mercury below the legal limits.

3. Fineness and residue (325 mesh)

The residue on the sieve is an indication of the fineness and dispersibility of the pigment. Cosmetic-grade products must control particle size for a smooth feel on the skin, whereas industrial-grade products must produce uniform colour without particles.

Water and water-soluble substances

Storage stability and dispersibility are affected by moisture. Water soluble matter is an indication of soluble salt impurities and must be strictly controlled.

5.Oil absorption & pH value

Oil absorption affects the amount of oil used in coating and ink formulations, while pH value affects compatibility with cement and coating base materials. Both require maintaining batch-to-batch stability.

6.Color difference

Colour difference is the key to ensure the stability of product colour, and the colour difference between batches must be controlled within the allowable range.

II. What are the uses of iron oxide brown?

Iron oxide brown, with its unique properties of "high tinting strength, high hiding power, light and weather resistance, and high safety," is used in a wide range of industries, including building materials, coatings, plastics, rubber, ceramics, papermaking, inks, leather, cosmetics, food, and daily necessities. All applications are listed below (without omissions):

1. Building material coloring pigments (in the construction and building materials industry, core industrial applications)

( 1 ) Iron oxide brown is used for coloring cement, cement tiles/tiles, concrete tiles, colored mortar, colored asphalt, terrazzo, mosaic and artificial marble, giving the products a weather-resistant and durable brown color. It is the most important use of iron oxide pigment in the building materials field, and is also suitable for outdoor decorative ground materials such as sidewalk paving bricks.

( 2 ) Iron oxide brown is used as a coloring pigment for interior and exterior wall coatings, anti-rust paints, color paints and wood coatings. It helps the coatings obtain a stable brown hue and improves the service life of the coating film with its excellent light and weather resistance. It is widely used in architectural coatings and industrial coatings.

( 3 ) Iron oxide brown is used for coloring wood coatings, wood-plastic composites (WPC) and wood flooring, helping wood products to obtain a weather-resistant brown hue, and is widely used in wood flooring, outdoor wood-plastic and furniture.

2. Plastic coloring pigments (plastics industry, industrial grade)

Iron oxide brown is used as a coloring pigment in plastic masterbatches and plastic products, helping plastic products obtain a uniform and stable brown hue. With its non-migrating, non-bleeding and heat-resistant properties, it is widely used in injection molding, extrusion and blow molding products.

3. Rubber coloring pigments (for the rubber industry, industrial grade)

Iron oxide brown is used as a coloring pigment for rubber products, helping rubber to obtain a weather-resistant brown hue. It is widely used in products such as tires, shoe soles, seals, and rubber flooring.

4. Ceramic glaze coloring pigments (ceramic industry, industrial grade)

Iron oxide brown is used as a coloring pigment in ceramic glazes, colored glazes, and building ceramics, helping ceramic products obtain a stable brown glaze surface. It is widely used in ceramic tiles, sanitary ware, and daily-use ceramics.

5. Paper coloring pigments (for the paper industry, industrial grade)

Iron oxide brown is used as a coloring pigment for paper and paperboard, helping paper products achieve a brown hue, serving the specialty paper and packaging paper industries.

6. Ink coloring pigments (industrial grade, ink printing industry)

Iron oxide brown is used as a coloring pigment in printing inks to help inks achieve a lightfast brown hue, and is widely used in packaging printing and specialty printing.

7. Leather coloring pigments (industrial grade, for the leather industry)

Iron oxide brown is used as a pigment for leather finishing and coloring, helping leather to achieve a natural brown hue, and is widely used in leather bags, shoes and leather goods.

8. Applications of magnetic materials (electronics industry, industrial grade, containing iron black component)

The iron black (Fe3O4) component in iron oxide brown is magnetic, and the related iron oxides can be used as magnetic raw materials for applications such as soft magnetic ferrite cores in the electronics industry, serving the electronics industry such as communication equipment and electronic transformers.

9. Cosmetic colorants (core application in the cosmetics industry)

Iron oxide brown is a cosmetic colorant approved by the US FDA and other regulations. It is used for brown coloring in makeup products such as lipsticks, eyeshadows, foundations, blushes, eyebrow pencils, and nail polishes . It can also be used for color correction in hair dyes and some personal care products. It helps products achieve a natural mineral brown hue and, due to its non-toxic and non-migrating properties, has become a preferred colorant for makeup formulations.

10. Food coloring agents (food sector, permitted by regulations)

Iron oxide pigments, including iron brown, are used as food colourants within the limits permitted by EU and other regulations (such as E172) to colour certain foods and beverages to achieve a stable brown hue in the products and must comply with the purity limits required by food regulations.

11. Coloring of toys and children's products (daily necessities sector)

Iron oxide brown that meets toy safety standards is used to colour toys, crayons, playdough and children’s stationery. This helps products achieve a bright, stable brown hue that meets safety requirements for children’s products.

12. Art pigments and stationery coloring (cultural products sector)

Iron oxide brown is used as a colour pigment in watercolours, oil paints, crayons, chalks and art supplies. It is used to produce lightfast, permanent brown colours and is much used in painting and art education.

Summary

Iron oxide brown (CAS No. 52357-70-7) (Fe2O3·FeO) is a brown-red coloured inorganic pigment made by mixing iron red, iron yellow and iron black. It is non toxic, resistant to chemicals, light and weather. It has high tinting strength, high hiding power and high safety and has become one of the most widely used iron oxide pigments. It is encountered in coloured floor tiles, wall paints, cosmetics, products of plastics and rubbers, ceramic sanitary ware, wood-plastic flooring, food, stationery and hair dye products in everyday life. Iron oxide brown is widely used in applications for colouring building materials, paints, plastics, rubber, ceramic glazes, papermaking, inks, leather, wood coatings and wood-plastic composites, paving and decorative materials, magnetic materials, cosmetics, food, toys and children products, art pigments and stationery, hair dyes and personal care products. This is a brown pigment for multiple applications, bridging the gap between "iron oxide pigment chemistry" and "building materials, paints, plastics, rubber, ceramics, leather, electronics, cosmetics, food, and daily necessities".