Our company is Yixing Wencheng Chemical Co., Ltd., a production plant of acrylate series including 1,6-hexanediol dimethacrylate (HDDMA). We have been engaged in the production and sales of acrylate series and their derivatives for more than 15 years. 1,6-Hexanediol dimethacrylate (HDDMA) is a bifunctional methacrylic acid active monomer with methacrylic acid double bonds at both ends and a straight-chain saturated C6 alkyl carbon chain in the middle. During the UV curing stage, the photoinitiator is excited and decomposed by ultraviolet light to generate free radicals. The methacrylic acid double bonds at both ends of HDDMA can undergo free radical copolymerization with photosensitive resins such as epoxy acrylic acid and polyurethane acrylic acid, and join the curing system to form a three-dimensional cross-linked network. The saturated hexyl carbon chain in the middle of the molecule remains in the paint film. As a reactive diluent monomer, HDDMA participates fully in film formation and curing with virtually no VOC emissions, effectively reducing the viscosity of the resin system. Compared to standard acrylates, the presence of methyl groups introduces greater steric hindrance; this, combined with the linear aliphatic carbon chain structure, enables the cured film to achieve an optimal balance between rigidity and toughness.
HDDMA has excellent overall performance, which can balance the various properties of the coating film, optimize the coating process and improve the adhesion of the substrate. This monomer possesses a unique ether-free C6 straight-chain aliphatic hydrocarbon molecular structure, coupled with the steric hindrance effect of methyl groups, exhibiting outstanding resistance to hydrolysis, damp heat, and heat aging, outperforming HDDA. Simultaneously, its moderate crosslinking density ensures good surface hardness and heat resistance of the coating film while retaining its toughness and bending resistance. This avoids the embrittlement problems easily caused by high-functionality monomers such as TMPTA and Di-TMPTA, effectively reducing curing internal stress, alleviating curing volume shrinkage, and minimizing microcracks in the coating. With its excellent linear aliphatic wettability, HDDMA can improve the spreading and leveling effect of resin on various substrates such as FR4 substrate, copper foil, and PET, reduce defects such as pinholes and craters, and significantly enhance the adhesion between the cured film and the substrate. Furthermore, as a low-viscosity difunctional monomer, it offers high dilution efficiency, effectively lowering the viscosity of UV resin systems and making it suitable for various application methods, including screen printing, roller coating, and spraying. Its methacrylate double bonds provide moderate reactivity, allowing for flexible control over curing rates; this prevents issues such as rapid surface drying with incomplete underlying cure, ensuring a uniform and stable curing outcome.
HDDMA possesses outstanding comprehensive value in terms of formulation differentiation, process optimization, and environmental protection. As a bifunctional crosslinking modified monomer, it can be compounded with high-functional monomers such as TMPTA and Di-TMPTA to effectively balance the hardness, heat resistance, chemical resistance and bending resistance of the coating film. It is suitable for high heat-resistant PCB solder resist, character ink, high-temperature protective coating, and thin substrate coating scenarios that require resistance to damp heat and long-term aging performance. It can enrich the UV resin formulation system and greatly improve the long-term reliability of the end coating. Meanwhile, the product's curing shrinkage is controllable, which can effectively improve problems such as coating micro-cracks and adhesion failure, reduce the risk of downstream rework and customer complaints, and significantly improve the yield of finished products. In addition, the monomer double bond can fully participate in UV crosslinking and curing, with no VOC volatilization, which fully meets the low VOC environmental protection control standards of the electronics industry.
Standard industrial-grade HDDMA contains impurities such as mono-methacrylates, oligomers, moisture, peroxides, and trace metal ions. These impurities can trigger issues like inconsistent photosensitivity, ion migration, yellowing during storage, and premature gelation, making the material unsuitable for high-reliability electronic UV resin systems. Electronic-grade HDDMA requires strict control over key quality parameters: effective monomer purity ≥98.5%, moisture ≤0.05%, and color ≤20 APHA. It demands precise control of the MEHQ polymerization inhibitor content, as well as rigorous limitation of metal ions (such as copper, iron, sodium, and potassium) and reduction of peroxide and aldehyde impurities. Such impurities pose significant risks to the reliability of electronic systems: metal ions can induce ion migration in PCBs under long-term hot and humid conditions, leading to current leakage and short-circuit failures; moisture and mono-ester impurities cause batch-to-batch fluctuations in photosensitivity and instability in the exposure window; peroxides and aldehydes lead to increased viscosity, yellowing, and premature gelation during storage; and color-related impurities result in dull PCB legend coatings, directly impairing circuit identification. Yixing Wencheng Chemical Co., Ltd. is a premium manufacturer of HDDMA; its products are widely used in industries such as electronic inks.
The reactivity of the double bonds in HDDMA is lower than that in HDDA; therefore, the photoinitiator dosage in the formulation must be adjusted accordingly to ensure thorough deep-curing of the coating. Regarding grade selection, HDDMA features a fixed C6 carbon chain structure without varying molecular weight grades; it is available only in industrial and high-purity electronic grades, with the latter being mandatory for electronic-grade UV resin products. Formulation strategies can be based on three established approaches: for rigid PCB solder mask UV resins, an epoxy acrylate system with TMPTA as the primary crosslinking monomer and 6%–12% HDDMA is used; for PCB legend ink UV resins, a polyurethane acrylate system with 8%–15% HDDMA is employed, with the optional addition of a small amount of TMPTA to enhance surface hardness; and for moisture- and heat-resistant flexible coating resins, an epoxy acrylate system with ≤10% HDDMA is utilized, supplemented by a small amount of PEGDA to adjust film flexibility. Additional notes for mass production: HDDMA cures more slowly than HDDA, so the photoinitiation system may need optimization if rapid curing is required; while its methyl structure enhances the coating's heat resistance, the film is slightly less flexible than that produced with HDDA, necessitating a balanced choice based on the specific temperature resistance and flexibility requirements of the end product.
Our company's 1,6-hexanediol dimethacrylate (HDDMA) has been widely and long-term used in the production of PCB inks. With fifteen years of deep industry experience, we remain committed to quality and production stability, and we warmly welcome customers from all sectors to contact us for inquiries and collaboration.
