N-Methylol Acrylamide (NMA) is a versatile water-soluble cross-linking monomer with the molecular formula C₄H₇NO₂ and a molecular weight of 101.10. It is characterized by its bifunctional groups, which include a vinyl group capable of polymerization and a reactive hydroxymethyl group that enables cross-linking. This unique structure makes NMA a valuable component in various industrial applications, particularly where enhancing the durability and performance of materials is required.

 Industrial Applications of N-Methylol Acrylamide

 1. Polymers and Copolymers

NMA is widely used as a cross-linking monomer in the synthesis of polymers and copolymers. It undergoes free radical polymerization with other vinyl monomers such as acrylonitrile, acrylamide, acrylic and methacrylic esters, vinyl chloride, and styrene. This reaction leaves the hydroxymethyl group available for further cross-linking, which improves the thermal stability and mechanical properties of the resulting polymers. For example, in situ polymerization of NMA has been shown to enhance the anti-mold properties of bamboo, increasing its mechanical properties by approximately 50% and making it suitable for broader applications in construction and building materials.

 2. Coatings and Paints

NMA is a key ingredient in the formulation of thermosetting resins, light-curing epoxy resin coatings, oil-resistant coatings, and baking-type coatings. Its ability to form cross-linked networks contributes to the durability and resistance of these coatings. NMA is also used in fluorinated acrylate copolymers, which are applied in paints and coatings for various surfaces. The compound’s reactivity allows it to integrate into polymer matrices, enhancing coating performance and longevity.

 3. Adhesives and Binders

NMA is employed in the production of adhesives and binders for textiles, leather, paper, wood, and metal. Its cross-linking functionality improves the adhesion strength and water resistance of these products. For instance, in non-woven fabric binders and printing paste adhesives, NMA provides enhanced bonding properties. When used in acrylic emulsion adhesives, it acts as a cross-linking agent, with typical usage levels ranging from 1% to 5% of the total monomer mass. Exceeding these levels can reduce initial tackiness, so precise formulation is necessary.

 4. Textile, Leather, and Paper Processing

The copolymers of NMA are used in fiber finishing agents, as well as in coatings for fabrics, leather, and paper. These applications leverage NMA’s ability to impart crease resistance, durability, and improved handle to textiles. In paper processing, it enhances the strength and water resistance of paper coatings. The compound’s compatibility with other monomers allows for tailored formulations to meet specific performance requirements in these industries.

 5. Soil Stabilization

NMA has been explored for use in soil stabilization and as a soil conditioner. Its cross-linking properties help in binding soil particles, thereby improving soil structure and stability. This application is particularly valuable in agricultural and construction contexts, where soil integrity is important.

 Regulatory and Safety Considerations

As of June 10, 2022, N-Methylol Acrylamide has been officially included in the SVHC (Substances of Very High Concern) list under the EU REACH regulation (Article 57a and 57b) due to its carcinogenic and mutagenic properties. This classification means that products containing NMA in concentrations above 0.1% require information transmission to downstream importers. If annual exports exceed one ton, notification to ECHA is mandatory. Additionally, since January 5, 2021, SCIP notification is required before placing products containing SVHCs on the EU market.

The World Health Organization’s International Agency for Research on Cancer (IARC) has listed NMA in Group 3 carcinogens. Safety data indicates that NMA is toxic if ingested, with an LD₅₀ of 420 mg/kg for rats, and can cause irritation to the skin, eyes, and respiratory tract. Proper handling and personal protective equipment are advised during its use.

 Global Market and Suppliers

The global market for NMA and its derivatives involves suppliers like Sigma-Aldrich Co LLC, Polysciences, Inc, and TCI. Production facilities exist worldwide, including in China, where companies such as Shenzhen Huaxinrui Biological Technology Co., Ltd. produce NMA and related compounds. NMA is typically available as a white crystalline powder or as a 48% aqueous solution.

 Conclusion

N-Methylol Acrylamide is a multifunctional chemical with significant applications in polymers, coatings, adhesives, and textile processing. Its role as a cross-linking agent enhances the performance and durability of various products. However, users must navigate regulatory requirements and adhere to safety guidelines due to its health and environmental hazards. Ongoing research continues to explore new applications, such as in eco-friendly materials, highlighting its continued relevance in industrial chemistry.