Our company is Yixing Wencheng Chemical Co., Ltd., a production plant of acrylate series including trimethylolpropane triacrylate (TMPTA). We have been engaged in the production and sales of acrylate series and their derivatives for more than 15 years. TMPTA is a trifunctional acrylate active crosslinking monomer with three polymerizable acrylic double bonds in its molecular structure. During the exposure stage of PCB liquid photosensitive solder resist ink and circuit ink, the photoinitiator generates free radicals, and the three double bonds simultaneously participate in the free radical copolymerization reaction of epoxy acrylic photosensitive resin to build a dense three-dimensional cross-linked network. At the same time, it has medium viscosity and can act as an active diluent to reduce the system viscosity of high viscosity photosensitive resin. It participates in film formation and curing throughout the process and will not evaporate and escape in the later stage like inactive organic solvents, thus avoiding defects such as pinholes, bubbles and VOC residues from the source.
TMPTA plays multiple key roles in electronic photosensitive ink formulations. Because its functionality is higher than that of bifunctional monomers such as DPGDA and TPGDA, its polymerization reaction rate is faster, which can effectively improve the UV photocuring speed, shorten the LED-UV exposure time, adapt to high-speed PCB production line production, and solve problems such as incomplete exposure of large board surfaces and surface stickiness. After curing, it can form a dense three-dimensional cross-linked network, increase the cross-linking density of the coating film, and significantly enhance the hardness, solvent resistance, thermal shock resistance, and chemical corrosion resistance of the solder resist layer. It is a key monomer for achieving high Tg heat resistance in AI servers and new energy vehicle PCB rigid boards. At the same time, it can be used as an active diluent to reduce the viscosity of epoxy acrylic resin systems and optimize the performance of ink screen printing, plate surface leveling, and other construction processes. As it contains no volatile components, it avoids defects like pinholes during pre-baking and mesh clogging often caused by conventional solvents. The cross-linking reaction is sufficient during the exposure stage, which can reduce side etching, residual adhesive and fine line pattern distortion during alkaline water development, and effectively improve the imaging yield of 25-50μm precision lines.
Electronic photosensitive inks have very high requirements for the quality of TMPTA. Ordinary industrial-grade TMPTA has problems such as residual monoesters and diesters, high moisture content, aldehyde impurities, and trace metal ions. These impurities can easily interfere with the photosensitive reaction, so it is not suitable for high-end PCB photosensitive inks. Manufacturers of electronic photosensitive inks must use high-purity electronic TMPTA, with key requirements including purity ≥99.5%, moisture ≤0.03%, color ≤15-20 APHA, low acid value, and strict control of heavy metal ions. This grade features extremely low impurity levels, ensuring no interference with the free-radical reactions of the photosensitive system, thereby maintaining stable exposure sensitivity and eliminating batch-to-batch photosensitivity drift. This grade of raw material has extremely low impurities, which will not interfere with the free radical reaction of the photosensitive system, ensuring stable exposure sensitivity and preventing ink photosensitivity drift between batches; low chromaticity ensures uniform color of solder resist green and white character ink on the board surface, without yellowing differences; low acid value prevents long-term storage of ink from corroding copper foil circuits and maintains stable ink viscosity; and strict control of trace metal ions can eliminate the risk of ion migration and leakage in the later stages of PCB manufacturing, meeting the incoming material inspection standards of electronic cleanrooms. At the same time, it should be noted that TMPTA has a high curing shrinkage rate, strong film rigidity, and weak flexibility. It should not be added alone in large doses. It must be compounded with flexible bifunctional monomers to release curing internal stress and reduce micro-cracks on the board surface. High addition amounts of FPC flexible circuit inks should be used with caution.
Electronic-grade TMPTA is an important tool for ink companies to achieve premium pricing for their products. After adding this monomer, the heat resistance, chemical resistance, and moisture resistance of solder resist inks are significantly upgraded, which helps companies win high-value-added orders such as AI computing motherboards and automotive new energy PCBs, thereby achieving premium pricing for finished ink products and breaking free from the price competition of low-end inks. Furthermore, the excellent batch-to-batch consistency of this high-purity raw material minimizes fluctuations in curing speed and heat resistance during mass production; this significantly lowers defect rates for downstream PCB customers—reducing issues like reflow soldering blisters and solder mask delamination—and cuts after-sales costs. Furthermore, when combined with TMPTA, it can form a differentiated monomer formulation matrix with TPGDA, DPGDA, and PHEA: DPGDA targets the general rigid board market, TPGDA focuses on flexible boards for new energy, and TMPTA focuses on the solder resist field of high heat-resistant server rigid boards, making it easier for ink manufacturers to provide customers with tiered and comprehensive rigid board ink solutions.
Growth in the current PCB industry is primarily driven by sectors such as AI server motherboards, high-performance computing (HPC) substrates, control boards for new energy vehicles, and high-frequency, high-speed rigid PCBs. These high-end products impose stringent requirements regarding thermal shock resistance, chemical resistance, and insulation reliability, thereby fueling a steady rise in demand for electronic-grade TMPTA. In contrast, traditional low-end PCB inks for home appliances can meet performance standards using industrial-grade TMPTA, with market competition centered on high-volume sales at low prices. Driven by the booming AI sector, the consumption of high-purity, low-metal-ion electronic-grade TMPTA is surging, positioning it to become a key growth raw material for rigid PCB photo-imageable inks.
Our Trimethylolpropane Triacrylate (TMPTA) has long been widely used in the production of PCB inks. Characterized by stable performance, superior quality, and reliable supply, our TMPTA products are exported to numerous countries worldwide. With fifteen years of deep industry experience, we remain steadfast in our commitment to quality and production stability, and we warmly welcome customers from all sectors to contact us for inquiries and collaboration.
