Isobornyl Acrylate (IBOA) and Isobornyl Methacrylate (IBOMA) are both acrylate ester monomers with bridged cyclic structures. They are one of important methacrylic ester monomer products on MMA (methyl methacrylate) business. The double bond in the (methyl) acrylate portion can undergo free radical polymerization and copolymerize with many other unsaturated monomers. Simultaneously, the nonpolar side groups on the polymer chain weaken intermolecular forces, reducing the viscosity of the polymer solution. The bridged cyclic structure of (methyl) acrylate makes it compatible with various resins, solvents, and coatings. On the other hand, the ester alkoxyl groups on the polymer chain contain large nonpolar bicyclic groups, enhancing spatial hindrance to protect the polymer chain. This contributes to strong the UV resistance, water resistance, and chemical resistance of (methyl) acrylate.
In acrylate, the double bond is a simple C=C bond, while in methacrylate, the double bond is a C=C bond with a methyl group attached to the carbon adjacent to the carbonyl group. This subtle structural difference affects the reactivity and performance of the monomers. Generally, the polymerization rate of methacrylates is slower than that of acrylates due to the additional methyl group hindering rotation around the double bond and influencing overall reactivity. The choice between IBOA and IBOMA can impact the performance of the resulting polymer. Generally, IBOMA may have a higher viscosity compared to IBOA, affecting the ease of the preparation process.
Above characteristics make Isobornyl Acrylate (IBOA) and Isobornyl Methacrylate (IBOMA) widely used in the manufacture of high-performance acrylic resins and acrylic emulsions. It is used as a tackifier, binder, reactive diluent, and curing agent in printing ink formulations, solvent-based high-solid clear coatings, and curing coatings. This component can make the coating film harder, while also maintaining and improving its elasticity. This enhances the gloss and adhesion of the coating. Properties such as leveling, friction resistance, aging resistance, and corrosion resistance of inks or coatings can benefit from its inclusion. The nonpolar bicyclic group in IBOMA has a strong spatial hindrance protection effect, and its application in waterborne coating formulations requires adjusting the system’s pH value to stimulate the activity of polymerization ends (CN110128585). IBOMA has good compatibility with various oligomers in UV curable coatings, which effectively lowers the viscosity of the system. It is suitable for high-solid content coating systems and reduces VOC emissions. At the same time, it can improve the adhesion, shrinkage rate, impact resistance and other physical properties of the coating. The majority of coatings used today are solvent-based, but the trend towards high-solid content coatings is on the horizon.
IBOA and IBOMA are active diluent with low volatility, toxicity, and irritation, which is beneficial for improving the production and construction environment of coatings. As this result, IBOMA has great application prospects in automotive coatings, high solid coatings, UV curable coatings, fiber optic coatings, modified powder coatings, adhesives, and other fields. It is suitable for manufacturing acrylic resins with high glass transition temperature (Tg), and its products have high hardness, high resistance to alcohol, and heat resistance. The acrylic polymer monomers have unique structures, providing excellent flexibility, adhesion, moisture resistance, and weather resistance. They are ideal for producing soft plastic film coatings like PET, PE, and PP, as well as decorative protective coatings for engineering plastic parts such as PE, PP, and PC.
Isobornyl (meth)acrylate can also function as an antibacterial, anti-mold, antioxidant, and plasticizer. In the plastic industry, It can improve the oxidation resistance and thermal stability of plastics, and has excellent processing performance. In addition, IBOA and IBOMA can be used as a viscosity improve in dental resins, which can reduce the polymerization shrinkage rate of resin based dental restoratives. When used in bone cement, it can reduce the adverse biological effects during cementation of implants.
Previous preparation methods involved the reaction of (methyl) methacrylate with Camphene in the presence of an acid catalyst, such as using Amberlyst 15 strong acid resin (US5672733) to obtain a reaction mixture. The reaction mixture was then subjected to vacuum distillation and washed with alkaline water to produce a composition containing Isobornyl Methacrylate (JP2006-69944). However, the method mentioned above has several drawbacks. Firstly, unreacted (methyl) methacrylate can negatively impact the color and storage stability. Secondly, a large amount of alkaline water is required for neutralization, resulting in the generation of alkaline wastewater. Currently, many patents focus on optimizing the selection of catalysts and improving the preparation process of IBOMA.
- Using photocatalysis method. Camphene, acrylic acid, polymerization inhibitor, and catalyst are uniformly mixed in a transparent reactor. The mixture is placed under UV light irradiation and stirred for the reaction. After the reaction is complete, rotary evaporation is carried out to obtain bio-based Isobornyl Methacrylate (CN112142593).
- Using molecular sieve as a catalyst. Employing a molecular sieve as the catalyst, (methyl) acrylic acid and Camphene are continuously converted to Isobornyl Methacrylate (IBOMA) in the reactor. (CN104529770)
- Using a solid acid catalyst mixture contains metal halides. The solid acid catalyst is prepared by mixing metal halides with water in a certain ratio. The catalyst is used to catalyze the reaction between acrylic acid and Camphene at temperatures ranging from 30°C to 90°C for 2 to 10 hours to produce Isobornyl Methacrylate (CN104815667).
- Using activated carbon-supported tin tetrachloride as a catalyst. Crude Camphene obtained from the isomerization of α-Pinene is reacted with methyl acrylic acid using activated carbon-supported tin tetrachloride as a catalyst. The reaction is conducted at 40°C to 60°C for 6 to 8 hours to obtain Isobornyl Methacrylate. (CN101863763)
The key players in Isobornyl Methacrylate include Mitsubishi Chemical Corporation, Röhm GmbH, Sumitomo Chemical, Evonik, DOW, and other companies. Mitsubishi Chemical has developed a series of methyl methacrylates based on methyl acrylic acid. Evonik has introduced the VISIOMER® product series. The Alpha, isobutene, and ACH processes are the main technologies used to prepare MMA. Since the disruption of the supply chain by COVID-19, the Alpha-process has had the lowest cost scheme (WANG NING, 2020). According to market data released by Sumitomo Chemical established the MMA division in 2022, the global demand for MMA was about 3 million tons in 2020, and the demand for acrylic resins was 1.3 million tons.