Our company is Yixing Wencheng Chemical Co., Ltd., a production plant of acrylate series including 1,6-hexanediol diacrylate (HDDA). We have been engaged in the production and sales of acrylate series and their derivatives for more than 15 years. 1,6-Hexanediol diacrylate (HDDA) is a bifunctional acrylic acid reactive diluent monomer. The molecule contains acrylic acid double bonds at both ends and a straight-chain saturated C6 alkyl carbon chain in the middle, and has a stable structure. When electronic ink is UV cured, the photoinitiator in the system is excited and decomposed by ultraviolet light to generate free radicals. The acrylic double bonds at both ends of HDDA can undergo free radical copolymerization with photosensitive resins such as epoxy acrylic acid and polyurethane acrylic acid, which are incorporated into the curing system and form a three-dimensional cross-linked network structure. Upon curing, the saturated hexyl chain of the HDDA remains within the coating film. This monomer participates in the film-forming and curing process with virtually no VOC emissions, offering excellent environmental performance; it also reduces ink viscosity and improves coating quality. Its linear aliphatic carbon chain structure imparts both rigidity and toughness to PCB coating films, effectively mitigating the brittleness often associated with high-functionality monomers and enhancing the overall performance of the cured film.
HDDA has comprehensive advantages in formulation applications. It has a stable C6 straight-chain aliphatic hydrocarbon structure, which can balance the hardness and toughness of the coating film and effectively reduce the internal stress during curing. Compared to the PEGDA ether system, this product has superior resistance to hydrolysis and damp heat. Compared to high-functionality monomers such as TMPTA and Di-TMPTA, its crosslinking density is moderate, which can avoid excessive embrittlement of the coating film. The cured coating film has both good surface hardness and excellent bending resistance, which can effectively alleviate the volume shrinkage caused by the curing of high-functionality monomers and reduce defects such as microcracks and film bursting on PCB boards. Meanwhile, its unique aliphatic chain structure has excellent substrate wettability, which can effectively improve the spreading and leveling effect of electronic inks on various commonly used substrates such as FR4 substrates, copper foil, and PET, improve the process problems in screen printing, spraying and other construction processes, reduce appearance defects such as pinholes, craters, and orange peel, stabilize the bonding interface between the paint film and the substrate, and greatly improve the adhesion and long-term stability of the product. As a low-viscosity bifunctional active monomer, HDDA has excellent dilution efficiency, which can significantly reduce the overall viscosity of the photosensitive resin system. It is perfectly compatible with various mainstream electronic ink molding processes such as screen printing, roller coating, and spraying. Moreover, the product can fully participate in UV crosslinking and curing without the need to add non-active solvents, thus eliminating the problem of solvent residue from the source and avoiding the reliability risks of electronic components caused by solvent residue. Furthermore, the molecular structure of this product contains no ether bonds, thereby completely eliminating the inherent drawback of ether bonds being prone to hydrolysis. The cured film exhibits superior resistance to acids and alkalis, MEK rubbing, boiling water, and damp-heat aging compared to PEGDA-series monomers, offering distinct advantages in high-end rigid PCB solder mask ink systems. Additionally, the product features a very low odor; compared to traditional aromatic monomers, it is safer and more environmentally friendly to produce and use, making it well-suited for large-scale industrial production.
HDDA offers outstanding value in terms of formulation differentiation, process optimization, and environmental friendliness. As a high-quality bifunctional crosslinking modified monomer, it can be compounded with high-functional monomers such as TMPTA and Di-TMPTA to precisely balance the hardness, chemical resistance and bending resistance of the coating film. It is suitable for PCB rigid board solder resist inks, character inks and various thin substrate protective inks with moisture and heat resistance requirements, effectively enriching the ink formulation system and greatly improving the reliability of end products. Meanwhile, its controllable curing shrinkage characteristics can effectively improve process defects such as micro-cracks on the board surface and adhesion failure, reduce PCB product rework losses and customer complaint risks, and significantly improve the yield of mass-produced finished products. Additionally, the double bonds in the HDDA molecule participate fully in UV cross-linking and curing with zero VOC emissions, fully complying with the electronics industry's stringent environmental standards for low VOC content.
HDDA is a widely used bifunctional reactive diluent monomer in the PCB electronic ink field. It is mainly suitable for rigid PCB solder resist inks, PCB character inks and UV protective coatings for rigid substrates. It can also be used in small quantities in FPC ink formulations that require high water resistance and humidity resistance. The product is positioned as a main crosslinking auxiliary monomer and is usually used in combination with high-functional monomers such as TMPTA and Di-TMPTA. It cannot be used alone as a main film-forming resin. Conventional industrial-grade HDDA has a high content of metal ions, monoesters and various impurities, which can easily lead to problems such as ion migration and poor storage stability under humid and hot conditions. It cannot meet the high reliability standards of high-end PCB products. Therefore, electronic ink manufacturers generally give priority to electronic-grade HDDA with higher purity and lower impurities. Currently, in the high-reliability rigid board ink sector, such as automotive PCBs and computing power carrier boards, the market demand for electronic high-purity HDDA remains stable.
Ordinary industrial-grade HDDA contains impurities such as monoacrylates, oligomers, moisture, peroxides, and trace metal ions, which can easily cause problems such as fluctuations in the photosensitivity of electronic inks, yellowing during storage, gelation, and ion migration, making it unsuitable for high-reliability electronic ink application scenarios. Electronic-grade HDDA requires strict control over core quality indicators: effective monomer purity ≥98.5%, moisture ≤0.05%, color ≤20 APHA, precise and controllable content of polymerization inhibitor MEHQ, strict control of metal ions such as copper, iron, sodium, and potassium, while ensuring low peroxide and low aldehyde impurity content. The hazards of various impurities are clear: metal ions are prone to migration in the humid and hot environment of PCB, leading to leakage and short circuit failure; moisture and monoester impurities can cause batch fluctuations in ink sensitivity and exposure window, affecting the development effect; peroxide and aldehyde impurities can cause ink viscosity to increase, yellowing, and premature gelation during storage; high chromaticity impurities can cause the character ink to darken, affecting circuit recognition. Yixing Wencheng Chemical Co., Ltd. is a high-quality manufacturer of HDDA, and its HDDA products have been widely used in various industries such as electronic inks.
In the practical operation of ink mass production, the amount of HDDA added needs to be strictly controlled, with the normal usage range being 5~18%; among them, the control range for high-reliability solder resist inks for automotive and computing power rigid boards is 5~12%, and the addition amount for FPC flexible inks is ≤10%. Excessive addition will reduce the elongation at break of the paint film, leading to product bending and cracking. HDDA has a single fixed carbon chain structure and no molecular weight distinction. It is only divided into industrial grade and electronic high-purity grade. Electronic ink production must uniformly select the electronic grade. Regarding formulation, rigid PCB solder mask inks utilize epoxy acrylate resin, TMPTA as the primary cross-linking monomer, and 6–12% HDDA. PCB legend inks are based on polyurethane acrylate with 8–15% HDDA and a small amount of TMPTA to enhance film hardness. Moisture- and heat-resistant FPC inks employ epoxy acrylate resin and ≤10% HDDA, combined with a small amount of PEGDA to adjust film toughness. In terms of production and storage, HDDA is a skin irritant, requiring enclosed handling and protective measures during charging; the product must be stored away from light and at controlled temperatures to prevent spontaneous polymerization. The standard charging sequence involves dispersing the resin, adding the monomer, and finally incorporating the photoinitiator. Formulation design must account for the fact that while HDDA-cured films offer superior rigidity compared to PEGDA, pure HDDA systems exhibit poor bending performance; therefore, HDDA should not be used alone or in high dosages within flexible ink systems.
Our company's 1,6-hexanediol diacrylate (HDDA) has been widely and long-term used in the PCB ink preparation process. Our HDDA products are stable in performance and excellent in quality, with a stable supply and are exported to many countries around the world. With 15 years of experience in the industry, we always adhere to quality and stable production capacity. We sincerely welcome customers from all walks of life to consult, negotiate and cooperate with us!
