Product Systems and Technical Features
I. Fluorine-Modified Acrylate UV Resins and Monomers
This product family introduces fluorine atoms into the acrylate molecular chain, leveraging the low molar refraction of fluorine to significantly reduce the resin's intrinsic refractive index. The incorporation of fluorine also modifies the material's surface properties: the cured coating exhibits low surface energy and shows repellency toward water and common organic solvents, which is of practical significance for anti-fouling and easy-to-clean coatings.
Key performance characteristics of this system include:
Refractive Index: Depending on fluorine content and molecular structure, the refractive index can be adjusted within the range of 1.38–1.45, with certain grades achieving even lower values.
Thermal Stability: The thermal decomposition temperature reaches up to 371 °C, providing good thermal stability in high-temperature operating environments (e.g., high-power optoelectronic devices, automotive displays).
Chemical Stability: The fluorinated structure endows the coating with resistance to acids, bases, and common organic solvents.
Dielectric Properties: The introduction of fluorine reduces the dielectric constant of the material, which helps minimize signal transmission loss in high-frequency communication applications.
In terms of product form, this system offers both resins and monomers. The resins serve as the primary film-forming material, suitable for coating applications requiring a certain film thickness and mechanical strength; the monomers act as reactive diluents or standalone functional materials, suitable for processes requiring low viscosity and high fluidity. This product series complies with the latest environmental regulations, including RoHS, REACH, and PFAS requirements.
II. Cationic-Curable Low Refractive Index UV Resins
The cationic curing system differs in reaction mechanism from conventional free-radical curing systems. Under UV irradiation, the cationic photoinitiator decomposes to generate acid, which then initiates ring-opening polymerization of epoxy or vinyl ether groups. Unlike the chain-growth mechanism of free-radical curing, cationic polymerization continues even after the UV light is turned off (dark reaction), which benefits deep-section curing and crosslinking in shadowed areas.
The advantages of the cationic system are primarily reflected in weatherability and chemical resistance. In 85 °C / 85 % RH (double 85) aging tests, this system can stably pass 2000 hours, with essentially no significant degradation in refractive index, adhesion, or appearance after curing, making it suitable for bonding and protective applications that demand long-term reliability.
In terms of product segmentation, cationic low-refractive-index UV resins are available in multiple grades ranging from flexible to rigid types, accommodating different mechanical requirements in bonding processes (e.g., curved bonding for flexible displays) and protective coatings (e.g., hard coatings for cover glass). Additionally, some grades support a dual photo‑thermal curing approach-post‑UV heating to enhance crosslink density and interfacial adhesion-offering flexibility to meet various process conditions and application scenarios.
III. Acrylate‑Based Low Refractive Index UV Resins
This system employs conventional free‑radical polymerizable acrylate structures and is fluorine‑free, thus offering particular advantages in fluorine‑free application scenarios. Its refractive index is primarily reduced by selecting monomers and resin backbones with low molar refraction, while maintaining the good curing reactivity characteristic of acrylate systems.
The acrylate system exhibits good interlayer adhesion and recoatability in multilayer composite optical film applications. In multilayer film structures, good adhesion between functional layers is essential to prevent delamination failure; meanwhile, when a subsequent layer must be coated onto an already cured surface, recoatability determines whether the upper material can spread uniformly and adhere well. This system has been optimized in this regard to meet the interlayer bonding requirements of multilayer composite films.
Typical Application Areas
The working principle of low‑refractive‑index materials is grounded in fundamental optical physics: when light passes from one medium into another medium with a lower refractive index, the interface reflection loss is significantly reduced. Three typical scenarios are described below.
Anti‑Reflection (AR) Coating
On display screens, optical lenses, and photovoltaic glass surfaces, ambient light is partially reflected at interfaces, reducing the transmitted light intensity. Coating the surface with a low‑refractive‑index material creates interference conditions due to the refractive index differences among the coating, air, and substrate. When the film thickness satisfies the quarter‑wavelength condition, the two reflected beams at the interface are out of phase and undergo destructive interference, thereby reducing reflectance and increasing transmitted light intensity.
Theoretically, a single‑layer AR coating can reduce the interface reflectance from about 4 % (air‑glass interface) to less than 1 %. In high‑end smartphones, automotive displays, and flexible screens, AR coatings have become standard. Moreover, applying AR coatings to photovoltaic module surfaces increases the utilization of incident light, positively contributing to module conversion efficiency.
Optical Fiber Coating (Fiber Cladding)
The basic structure of an optical fiber consists of a core and a cladding, where the cladding material must have a refractive index lower than that of the core to satisfy the total internal reflection condition. As an optical fiber coating, the low‑refractive‑index UV resin's refractive index must be matched to that of the core. For example, with a silica core (refractive index about 1.46), the cladding material needs a refractive index below that value, and fluorine‑modified acrylate systems (approximately 1.38–1.40) meet this requirement. This application demands high transparency and long‑term stability of the material, as well as rapid curing during the fiber‑drawing coating process.
Other Application Directions
The chemical resistance and low surface energy of fluorine‑modified low‑refractive‑index UV resins also find practical use in new energy battery packaging, medical device coatings, and 5G high‑frequency communication components. Methoxy acrylate UV monomers can be used in printing inks, adhesives, and photoresists to adjust adhesion and curing speed in formulation development.