Moneide Chemicals
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Direct Red 28
Chemiese naam |
Direct Red 28 |
Sinonieme |
C.I.22120;Disodium3,3'-[[1,1'-biphenyl]-4,4'-diylbis(azo)]bis(4-aminonaphthalene-1-sulphonate) |
CAS No. |
573-58-0 |
Molekulêre formule |
C32H22N6Dit2O6S2 |
EINECS No. |
209-358-4 |
Molekulêre gewig |
696.66 |
Molekulêre struktuur |
|
Besonderhede |
Appearance: brownish red powder pH change range: 3.0(blue)~5.2(red) Water Soluble Test: pass Loss on drying: 5.0% max. Sulfated ash(as SO4): 27% max. |
Hooftoepassing |
Used as pH-indicator, adsorption indicator and biological dye, etc. |
- Cellulose Fiber Dyeing: Direct Red 28 is widely used in the textile industry for dyeing cellulose - based fibers. It can produce a deep and vivid red color on cotton fabrics, which is highly desirable in the production of clothing, home textiles, and industrial fabrics. The dyeing process is relatively simple and cost - effective, making it a popular choice for textile manufacturers. For example, in the production of red - colored cotton T - shirts, Direct Red 28 can provide a consistent and long - lasting color that resists fading even after multiple washes.
- Fabric Printing: It is also used in fabric printing processes. The high solubility of Direct Red 28 allows it to be easily incorporated into printing pastes, enabling the creation of intricate red - colored patterns on fabrics. This is commonly seen in the production of printed curtains, upholstery fabrics, and fashion garments.
- Paper Dyeing: In the paper industry, Direct Red 28 is used to color various types of paper products. It can be added to the pulp during the paper - making process to produce red - colored papers for applications such as stationery, packaging, and decorative papers. The dye evenly distributes in the pulp, resulting in a uniform and attractive red color throughout the paper. For instance, red - colored gift - wrapping papers often use Direct Red 28 to achieve their vibrant appearance.
- Paperboard and Cardstock: It is also suitable for coloring paperboard and cardstock, which are used in the production of boxes, folders, and other packaging materials. The excellent color fastness of Direct Red 28 ensures that the printed or dyed paperboard products maintain their color integrity during storage and transportation.
- Leather Dyeing: Direct Red 28 can be used to dye leather, imparting a rich red color to the leather surface. It penetrates the leather fibers effectively, providing a long - lasting and uniform color. This is useful in the production of leather goods such as handbags, shoes, and furniture upholstery. The dye can enhance the aesthetic appeal of the leather products and make them more visually appealing to consumers.
- Biological Staining: In some biological applications, Direct Red 28 can be used as a staining agent. It can bind to certain biological materials, such as proteins and polysaccharides, allowing for their visualization under a microscope. For example, in histological studies, it can be used to stain tissue sections to highlight specific structures.
- Food Industry (where permitted): In some regions where it is approved for food use, Direct Red 28 can be used as a food colorant. It can be added to certain food products such as confectionery, beverages, and dairy products to enhance their visual appeal. However, strict regulations govern its use in the food industry to ensure safety.
- Direct Red 28 may be harmful if swallowed, inhaled, or absorbed through the skin.
- Prolonged or repeated exposure may have adverse effects on health. Some studies have suggested potential carcinogenicity, although the exact risks are still under investigation.
- Contact with strong oxidizing agents can lead to dangerous reactions.
- When handling this product, always wear appropriate personal protective equipment, including chemical - resistant gloves, safety goggles, and a lab coat or protective apron.
- Work in a well - ventilated area, preferably under a fume hood, to avoid inhalation of dust or fumes.
- In case of contact with skin, immediately wash the affected area with plenty of water for at least 15 minutes and seek medical advice. If the compound gets into the eyes, rinse the eyes thoroughly with water for at least 15 minutes, lifting the eyelids occasionally, and then seek immediate medical attention.
- Do not eat, drink, or smoke in the area where Direct Red 28 is being used.
- Store Direct Red 28 in a cool, dry place, away from direct sunlight and heat sources.
- Keep it in a tightly sealed container to prevent moisture absorption and contact with air, which could potentially affect its chemical properties and color quality.
- Store it separately from incompatible substances such as strong oxidizing agents and acids to avoid dangerous reactions.
Is Direct Red 28 safe for skin?
Direct Red 28 (also known as Congo Red) is not considered safe for direct skin contact or cosmetic use. While it has been historically used as a biological stain and textile dye, studies indicate potential skin irritation and sensitization risks. The compound can penetrate skin barriers and has been linked to allergic reactions in some individuals. Regulatory agencies classify it as a possible carcinogen based on animal studies, restricting its use in products that contact skin. Proper protective equipment (gloves, lab coats) is recommended when handling this dye in industrial or laboratory settings to minimize exposure risks.
What is Direct Red 28 used for?
Direct Red 28, commonly called Congo Red, is primarily used as a histological stain in microscopy to detect amyloid fibrils in tissues, where it exhibits a characteristic red-to-green birefringence under polarized light. Industrially, it serves as a textile dye for cotton and silk due to its vivid red color. In research, it aids in studying protein aggregation diseases like Alzheimer’s. However, its use has declined in consumer textiles due to toxicity concerns, with safer synthetic alternatives now preferred for dyeing applications.
What is another name for Direct Red 28?
The most widely recognized alternative name for Direct Red 28 is Congo Red, derived from its early use in dyeing African cotton. It’s also classified as C.I. 22120 in the Color Index system. In scientific literature, it may be referred to by its chemical name, disodium 3,3′-([1,1′-biphenyl]-4,4′-diyl)bis(4-aminonaphthalene-1-sulfonate). These names are used interchangeably depending on the context—textile industry, biological staining, or chemical research—though "Congo Red" remains the most common colloquial term.