Direct Red 28, widely identified by its scientific nomenclature and molecular formulation (C32H22N6Na2O6S2), is an essential anionic disazo dyestuff. In chemical and diagnostics circles, it is widely recognized under the synonym Congo Red. Featuring a symmetrical biphenyl core coupled with two naphthalene sulfonic acid groups, this complex chemical structure grants Direct Red 28 exceptional binding affinity to cellulosic substrates through non-covalent forces such as hydrogen bonding and van der Waals interactions.
Historically, Direct Red 28 revolutionized the textile and coloring industries as the first direct dye capable of binding directly to cotton without requiring a mordant. In modern chemical manufacturing, its role has transitioned into a highly specialized chemical compound utilized in analytical laboratories, diagnostic medicine (such as identifying amyloidosis in histology), biochemical research, and precise paper and plastic staining processes.
"Understanding the precise molecular orientation and chemical properties of Direct Red 28 is essential for engineering superior coloration consistency, high fastness ratings, and customized pH-sensitive indicators."
The global demand for Direct Red 28 continues to evolve. While traditional textile uses have transitioned toward eco-friendly alternatives in many jurisdictions, industrial demand has surged in fields such as biomedical diagnostics, biochemistry research, analytical chemistry, paper manufacturing, and concrete additives. Due to its intense color and biological affinity, it serves as a crucial diagnostic marker for detecting amyloid proteins in histological sections.
In industrial sectors, it is a key component for manufacturing specialized papers, indicator test strips, and functional plastic compounds. Enterprise procurement teams require a reliable partner who can navigate global regulations. Chemical regulatory frameworks such as Europe's REACH, USA's TSCA, and environmental standards (like ZDHC and GOTS) mandate strict control over amine impurities, making high-purity synthesis of Direct Red 28 a top priority.
At Tianjin Sunrise Chem Group, we combine advanced digital manufacturing with strict eco-compliance, ensuring consistent quality, cost efficiency, and reliable global logistics.
Our integrated chemical sourcing and efficient logistics help reduce costs. By managing both raw material synthesis and shipping logistics, we ensure cost stability even in volatile markets.
Different industries require unique dye specifications. Our R&D team can adjust pH sensitivity, molecular purity levels, and physical delivery formats (liquid or powder) to meet your target applications.
We strictly adhere to zero hazardous chemical discharge standards. With ZDHC Level 3 and GOTS certifications, we support brands in building green, environmentally-responsible supply chains.
Tianjin Sunrise Chem Group, specializes in manufacturing high-quality dyestuffs. Including Direct dyes, Acid dyes, Basic dyes, Sulphur dyes, Solvent dyes, Liquid dyes and Fluorescent dyes.
Backed by decades of industry and export experience, we have built a reputation for reliability and excellence, serving clients from diverse sectors including denim, textile, leather, paper and plastic.
We always highly focus on the goods quality and stability. Each shipment has been tested before sending to the port. ZDHC level 3 and GOTS certificate makes your quality guaranteed.
We pride ourselves on offering customized solutions. Our team of experts works closely with clients to understand their unique needs and delivers tailored products and services. We actively seek strategic partnerships to expand our reach and enhance our offerings. Collaborate with us to explore mutual growth opportunities.
Environmental protection is the cornerstone of our innovation. We dedicate ourselves to provide clients with eco-friendly, high-quality colorants that balance productivity with environmental harmony, driving the industry towards a more sustainable development path while delivering high-performance products—for a greener textile industry and a sustainable future.
Cooperating with textile and paper mills for many years shows that the factory has established a strong and reliable business relationship. This kind of long-term collaboration can bring numerous benefits, such as consistent orders, shared resources, and mutual support. It also indicates that the factory has a good track record of delivering quality products and meeting the needs of its partners. Our mission is to drive business growth by providing reliable and customized products. Our goal is to make a significant contribution to our customers' success by consistently delivering first-class products and exceptional customer service. By building lasting partnerships, we strive to be a catalyst for our clients' success.
With years of experience, we have successfully established strong partnerships in many countries. Our dedication to meeting global demands and exceeding customer expectations has earned us a reputation as a reliable supplier worldwide. If you are looking for reliable, high-quality Dyes, we invite you to choose us as your trusted partner.
Achieving ZDHC Level 3 and GOTS certifications proves that our company has implemented robust chemical management procedures and meets strict requirements for handling, wastewater treatment, and pollution prevention.
We prioritize long-term cooperation, providing high-quality dyes and pigments while ensuring reliable logistics and secure shipping container arrangements.
One of the main reasons why customers choose us is the stable supply of dyes we provide. We have developed efficient manufacturing processes to ensure a continuous supply of our products. Our factories feature state-of-the-art equipment and a knowledgeable workforce, which enables us to fulfill the most demanding orders.
Detailed chemical, mechanical, and logistical guidance to assist chemical engineers, laboratory coordinators, and supply chain managers.
Direct Red 28 (Congo Red) is used in histopathology staining (such as identifying amyloidosis in biological samples) and serves as a pH indicator (turning blue-violet below pH 3.0 and red above pH 5.2). It is also utilized in papermaking, scientific research laboratories, and for coloration of concrete and plastic compounds.
We maintain strict control over chemical synthesis inputs and raw materials to prevent restricted substances from entering the manufacturing process. Our wastewater treatment facilities and in-house testing laboratories analyze each production batch for traces of restricted aromatic amines, heavy metals, and other priority hazardous substances, meeting the strict standards of ZDHC Level 3 and GOTS.
Yes. Sunrise Chem Group provides customized solutions. We can manufacture Direct Red 28 in specialized powder grades, granular forms, or standardized aqueous solutions depending on your laboratory, diagnostic, or industrial process requirements.
Standard packaging includes moisture-proof 25kg fiber drums, multi-layer paper bags, or custom bulk bags, all designed to prevent moisture absorption and chemical degradation. When stored in a cool, dry, and well-ventilated warehouse away from acids, Direct Red 28 maintains its stability and color integrity for up to 36 months.
Our Factory 4.0 production framework utilizes automated monitoring of raw material stock, predictive production scheduling, and direct port connectivity. This ensures that manufacturing runs continuously, minimizing bottleneck periods and helping global procurement teams maintain consistent production lines.
Sunrise
