Our company is Yixing Wencheng Chemical Co., Ltd., a production plant of acrylate series including bis(trimethylolpropane) acrylate (Di-TMPTA). We have been engaged in the production and sales of acrylate series and their derivatives for more than 15 years. Di-TMPTA is a tetrafunctional acrylate monomer with four acrylic double bonds in its molecular structure that can participate in polymerization. During the UV exposure stage of PCB photosensitive ink, the photoinitiator is decomposed by light to generate free radicals. The four double bonds simultaneously undergo free radical copolymerization with the epoxy acrylic photosensitive resin to build a high-density three-dimensional cross-linked network. The macromolecular skeleton has ether bonds and is longer than the TMPTA chain segment, which moderately buffers the brittleness of the paint film while achieving high cross-linking density.
Meanwhile, Di-TMPTA is an active monomer that can reduce viscosity to a certain extent. It participates entirely in the curing and film formation process, with no VOC volatilization, thus avoiding process defects such as pinholes, bubbles, and residues caused by ordinary inactive solvents.
Di-TMPTA, as a high-end tetrafunctional crosslinking monomer, has comprehensive performance advantages in PCB photosensitive solder resist ink systems. Its unique tetrafunctional molecular structure can significantly increase the cross-linking density of the coating film, effectively improve the pencil hardness, resistance to MEK solvent wiping, and resistance to chemical gold etching of the solder resist layer, and simultaneously increase the glass transition temperature (Tg) of the coating film, significantly enhancing the thermal shock resistance of lead-free reflow soldering. It can perfectly adapt to the stringent usage standards of high-reliability high-end boards such as AI computing power carrier boards and automotive power PCBs. Furthermore, the monomer exhibits excellent acrylic double-bond reactivity; when used in formulations, it boosts the overall UV curing rate, resolving process issues like incomplete bottom curing in thick ink layers and surface tackiness, thereby enabling high-speed LED-UV mass production and enhancing line efficiency. Compared to conventional trifunctional TMPTA, Di-TMPTA has a larger molecular weight and a lower curing volume shrinkage rate, which can significantly reduce the internal stress generated by thick film curing, effectively improve defects such as circuit edge shrinkage and board warping, and accurately ensure the imaging quality of fine lines and narrow-pitch precision lines. In addition, the flexible segments of the molecular chain with built-in ether bonds can effectively improve the drawback of the brittleness of the coating film after curing of high-functional monomers. While maintaining the high hardness of the coating film, it optimizes the toughness, greatly reduces the risk of high-temperature cracking of thick solder resist layers on hard boards, and has excellent compatibility with mainstream photosensitive resins such as epoxy acrylic and phenolic epoxy, with extremely strong formula adaptability.
Di-TMPTA has certain performance shortcomings in formulation applications: compared with conventional TMPTA, its bulk viscosity is higher, its system activity viscosity reduction ability is weaker, and because of its extremely high tetrafunctional crosslinking density, its single addition or excessive addition will lead to a significant increase in the brittleness of the paint film, making it prone to cracking under bending and thermal shock in the later stage. Therefore, it is not suitable to be used alone as the main crosslinking monomer. In actual mass production formulations, a gradient compounding system is used to achieve complementary performance: trifunctional TMPTA is used as the basic main crosslinking monomer to ensure the system's rapid curing efficiency and basic heat and solvent resistance; Di-TMPTA is used as a high-end reinforcing and modifying component, with the optimal addition range of 2~6% strictly controlled to specifically improve the Tg point, thick film heat resistance, and resistance to chemical metals and solvents; at the same time, flexible bifunctional monomers such as TEGDA and TEGDMA are combined to effectively neutralize the brittle defects of the coating film caused by high-functionality monomers, and comprehensively improve the bending resistance and long-term damp heat stability of the solder resist layer. For special formulation systems, some polyurethane modified photosensitive resins have limited compatibility with the monomer. Compatibility testing must be carried out in advance before mass production to avoid process risks such as batch gloss loss, delamination, and performance fluctuations.
High-end PCB photosensitive ink production requires strict selection of electronic high-purity Di-TMPTA. Ordinary industrial-grade products contain impurities such as monoester, diester residue, moisture, aldehydes, and trace metal ions, which can easily cause product performance defects and are completely unsuitable for the production requirements of high-end inks. The core quality indicators for electronic grade products must meet the following requirements: purity ≥ 99.0%, moisture ≤ 0.03%, and color 15-20 APHA. At the same time, key impurities such as metal ions, aldehydes, and residual mono- and diesters must be strictly controlled, and the content of MEHQ polymerization inhibitors must be precisely controllable to ensure the stability of the formulation. Various impurities can significantly harm the ink system: residual moisture and monoesters can cause batch drift in ink photosensitivity, leading to unstable curing effects; trace metal ions can cause ion migration and leakage hazards during long-term use of PCB products, reducing the insulation reliability of the products; aldehyde impurities can easily cause ink discoloration and gelation during storage; high acid values can not only corrode PCB copper foil, but also cause ink viscosity drift during storage, seriously affecting the consistency of production batches and the yield of finished products. Yixing Wencheng Chemical Co., Ltd. is a high-quality manufacturer of Di-TMPTA. Its electronic-grade Di-TMPTA has been widely used in various industries such as electronic photosensitive inks.
In the current PCB ink market, traditional general-purpose rigid board formulations mostly use TMPTA as the core crosslinking monomer, which is difficult to meet the stringent performance standards of high-end boards. With the rapid development of high-end tracks such as AI server computing power carrier boards, automotive high-power PCBs, and high-reliability thick film solder resist, the industry's requirements for the core performance of inks, such as high Tg, chemical resistance, and high-temperature reflow soldering resistance, continue to upgrade, driving the steady increase in market demand for high-purity electronic-grade Di-TMPTA. Positioned as a high-end reinforcing and modifying monomer, Di-TMPTA complements TMPTA through synergistic formulation, offering unique properties that conventional monomers cannot replicate; consequently, there is a significant supply gap for low-metal-ion, high-purity electronic-grade Di-TMPTA, presenting substantial growth potential. For ink manufacturers, this monomer has extremely high commercial value: through the classic TMPTA+Di-TMPTA compound system, ultra-high heat-resistant thick-film solder resist inks can be developed, precisely targeting high-value-added end markets such as computing power and automotive, breaking free from price competition in low-end industries and achieving high-end product premiums; relying on the advantages of controllable impurities and strong batch consistency of electronic-grade monomers, reliability issues such as reflow soldering blistering and solder resist layer cracking and damage in downstream PCB products can be effectively reduced, significantly lowering after-sales customer complaints and maintenance costs; at the same time, it can help companies build a tiered product formulation system, using conventional TMPTA formulations for general-purpose boards and compound formulations for high-end, high-heat-resistant thick-film boards, enriching the product matrix and market selection, comprehensively covering the performance needs of customers at different levels, and enhancing overall market competitiveness.
Our company's bis(trimethylolpropane) acrylate (Di-TMPTA) has been widely and long-term used in the PCB ink preparation process. 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 potential collaboration.
