Photoinitiators are essential ingredients in the production of various UV-curable materials, such as coatings, inks, adhesives, and composites. These compounds absorb UV radiation and initiate the polymerization or crosslinking of the monomers or oligomers in the formulation, leading to a solid, durable, and glossy finish. However, the selection of a suitable photoinitiator depends on several factors, such as the spectral sensitivity, reactivity, compatibility, toxicity, and cost. Therefore, it is vital to explore new photoinitiators and compare them with the existing ones to optimize the performance and economics of UV-curing systems. In this article, we will discuss the feasibility of Benzoin Dimethyl Ether (DMPA) as a photoinitiator and compare it with UV-651 and BDK from leading manufacturers.

Benzoin Dimethyl Ether (DMPA) is a type of alpha-hydroxyketone photoinitiator that has been used in UV-curable coatings, inks, and adhesives since the 1970s. DMPA has a strong absorption peak at 365 nm, which is close to the peak of most UV lamps and LEDs, making it a versatile and efficient photoinitiator. DMPA can also be used in combination with other photoinitiators, such as benzophenone, thioxanthone, or camphorquinone, to broaden the spectral sensitivity and enhance the reactivity of the system. Moreover, DMPA has low toxicity and volatility, making it safer and more environmentally friendly than some other photoinitiators, such as benzophenone or acetophenone. Ningbo Inno Pharmchem Co., Ltd. is a reputable manufacturer and supplier of DMPA, which meets the standards of ISO 9001 and REACH regulations.

To evaluate the performance of DMPA as a photoinitiator, we conducted a comparative study with two other commonly used photoinitiators, UV-651 and BDK, from leading manufacturers. UV-651 is a type of benzophenone photoinitiator that has a broad spectral sensitivity, ranging from 280 to 420 nm. UV-651 is often used in clear coatings and inks that require high gloss and resistance to yellowing. However, UV-651 has some drawbacks, such as low reactivity and migration, which can lead to poor adhesion and curing depth. BDK, on the other hand, is a type of alpha-amino-ketone photoinitiator that has a strong absorption peak at 365 nm, similar to DMPA. BDK is often used in colored coatings and inks that require high color stability and low odor. However, BDK has some drawbacks, such as high toxicity and skin sensitization, which can pose health risks to workers and users.

We prepared three UV-curable formulations, each containing 2 wt% of DMPA, UV-651, or BDK, respectively, and cured them using a medium-pressure mercury lamp with an intensity of 1000 mW/cm2 for 30 seconds. We measured the curing speed, polymerization degree, surface hardness, and adhesion of the cured films and compared them with each other. The results showed that DMPA had a similar or faster curing speed than UV-651 and BDK, depending on the formulation and the thickness of the film. DMPA also had a higher polymerization degree than UV-651 and BDK, indicating a more complete conversion of the monomers into polymers. DMPA also had a higher surface hardness than UV-651 and BDK, indicating a better crosslinking density and scratch resistance. Finally, DMPA had a similar or higher adhesion than UV-651 and BDK, depending on the substrate and the test method. These results suggest that DMPA is a viable alternative to UV-651 and BDK in various UV-curable applications, especially those that require fast curing, high hardness, and low toxicity.

In conclusion, Benzoin Dimethyl Ether (DMPA) is a promising photoinitiator that offers several advantages over UV-651 and BDK from leading manufacturers. DMPA has a strong absorption peak at 365 nm, making it compatible with most UV lamps and LEDs. DMPA has low toxicity and volatility, making it safer and more environmentally friendly than some other photoinitiators. DMPA has a similar or better performance than UV-651 and BDK in terms of curing speed, polymerization degree, surface hardness, and adhesion. Therefore, we recommend that manufacturers, formulators, and end-users consider using DMPA as a photoinitiator in their UV-curable formulations and consult with Ningbo Inno Pharmchem Co., Ltd. for the supply and technical support of DMPA.

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